Computed body tomography with MRI correlation. [4th ed.] 9780781745260, 0781745268

Table of contents :
U S E R M A N U A L......Page 1
Basic Principles of Computed Tomography Physics and
Technical Considerations......Page 5
I m a g i n g w i t h X - R a y s......Page 6
B r i e f H i s t o r y o f C o m p u t e d T o m o g r a p h y......Page 8
G e n e r a t i o n o f X - R a y s......Page 11
G a n t r y E l e c t r o m e c h a n i c s......Page 13
H e l i c a l / S p i r a l S c a n n i n g......Page 14
D e t e c t o r C o n f i g u r a t i o n......Page 15
C O M P U T E D T O M O G R A P H Y I M A G E F O R M A T I O N X - R a......Page 17
I m a g e R e c o n s t r u c t i o n F r o m T w o - D i m e n s i o n......Page 19
T o m o g r a p h y : L i n e a r I n t e r p o l a t i o n......Page 20
M u l t i d e t e c t o r R o w S p i r a l C o m p u t e d T o m o g......Page 21
S i g n a l......Page 22
R e s o l u t i o n......Page 23
I n - P l a n e S p a t i a l R e s o l u t i o n......Page 24
L o n g i t u d i n a l S p a t i a l R e s o l u t i o n ( S l i c e......Page 25
C o n t r a s t ( L o w - c o n t r a s t ) R e s o l u t i o n......Page 26
T e m p o r a l R e s o l u t i o n......Page 27
N o i s e......Page 29
I M A G E V I S U A L I Z A T I O N A N D A N A L Y S I S......Page 31
M u l t i p l a n a r R e f o r m a t i o n ( T w o - D i m e n s i o n a......Page 32
S h a d e d - S u r f a c e D i s p l a y a n d V o l u m e - R e n d e......Page 34
P e r s p e c t i v e - R e n d e r i n g D i s p l a y ( T h r e e D i m......Page 36
I m a g e A n a l y s i s a n d C o m p u t e r - A i d e d D i a g n......Page 37
C O M P U T E D T O M O G R A P H Y S C A N P A R A M E T E R S C o l l......Page 39
C o m p u t e d T o m o g r a p h y T a b l e T r a v e l S p e e d......Page 42
T u b e V o l t a g e a n d C u r r e n t......Page 46
R e c o n s t r u c t i o n K e r n e l......Page 47
S e c t i o n T h i c k n e s s......Page 48
R A D I A T I O N D O S E......Page 51
R a d i a t i o n D o s i m e t r y P a r a m e t e r s S p e c i f i c......Page 52
T A B L E 1 - 1 C O M P A R I S O N O F E F F E C T I V E R A D I A......Page 55
E f f e c t i v e D o s e ( m S v )......Page 56
A p p r o a c h e s t o R e d u c e R a d i a t i o n D o s e......Page 57
E M E R G I N G C O M P U T E D T O M O G R A P H Y A P P L I C A T I O N......Page 59
P o s i t r o n E m i s s i o n T o m o g r a p h y в Ђ “ C o m p u t e d......Page 61
R E F E R E N C E S......Page 63
Magnetic Resonance Imaging Principles and Applications......Page 67
P R O D U C T I O N O F N E T M A G N E T I Z A T I O N......Page 68
N e u t r o n s......Page 74
C O N C E P T S O F M A G N E T I C R E S O N A N C E......Page 75
T 1 R e l a x a t i o n a n d S a t u r a t i o n......Page 83
T 2 R e l a x a t i o n , T 2 * R e l a x a t i o n , a n d S p i n......Page 88
P R I N C I P L E S O F M A G N E T I C R E S O N A N C E I M A G I N G......Page 94
S l i c e S e l e c t i o n......Page 95
R e a d o u t o r F r e q u e n c y E n c o d i n g......Page 98
P h a s e E n c o d i n g......Page 101
D a t a A c q u i s i t i o n T e c h n i q u e s......Page 105
R a w D a t a a n d I m a g e D a t a M a t r i c e s......Page 107
D a t a C o l l e c t i o n M e t h o d s......Page 109
P U L S E S E Q U E N C E S......Page 115
S p i n E c h o S e q u e n c e s......Page 116
G r a d i e n t E c h o S e q u e n c e s......Page 120
E c h o P l a n a r I m a g i n g S e q u e n c e s......Page 123
M a g n e t i z a t i o n - P r e p a r e d S e q u e n c e s......Page 125
M E A S U R E M E N T P A R A M E T E R S A N D I M A G E C O N T R A S......Page 133
I n t r i n s i c P a r a m e t e r s......Page 134
E x t r i n s i c P a r a m e t e r s......Page 137
A D D I T I O N A L S E Q U E N C E M O D I F I C A T I O N S......Page 140
F a t S a t u r a t i o n......Page 141
C o m p o s i t e P u l s e s......Page 145
A R T I F A C T S......Page 147
M o t i o n A r t i f a c t s......Page 148
S e q u e n c e - / P r o t o c o l - R e l a t e d A r t i f a c t s......Page 151
A l i a s i n g......Page 152
C h e m i c a l S h i f t A r t i f a c t s......Page 154
P h a s e C a n c e l l a t i o n A r t i f a c t......Page 156
T r u n c a t i o n A r t i f a c t s......Page 157
O u t - o f - p h a s e T E , m s......Page 158
C o h e r e n c e A r t i f a c t s......Page 160
M a g n e t i c S u s c e p t i b i l i t y D i f f e r e n c e A r t i......Page 161
E x t e r n a l A r t i f a c t s......Page 162
M a g n e t i c F i e l d D i s t o r t i o n s......Page 163
M e a s u r e m e n t H a r d w a r e......Page 164
N o i s e......Page 165
M O T I O N A R T I F A C T R E D U C T I O N T E C H N I Q U E S......Page 167
A c q u i s i t i o n P a r a m e t e r M o d i f i c a t i o n......Page 168
T r i g g e r i n g / G a t i n g......Page 169
F l o w C o m p e n s a t i o n......Page 174
M A G N E T I C R E S O N A N C E A N G I O G R A P H Y......Page 175
T i m e - o f - F l i g h t M a g n e t i c R e s o n a n c e A n g i o......Page 178
P h a s e - C o n t r a s t M a g n e t i c R e s o n a n c e A n g i o......Page 179
M a x i m u m - I n t e n s i t y P r o j e c t i o n......Page 181
P e r f u s i o n......Page 183
U l t r a h i g h F i e l d I m a g i n g *......Page 185
I N S T R U M E N T A T I O N......Page 187
C o m p u t e r S y s t e m s......Page 188
M a g n e t S y s t e m......Page 191
G r a d i e n t S y s t e m......Page 194
R a d i o f r e q u e n c y S y s t e m......Page 196
D a t a A c q u i s i t i o n S y s t e m......Page 198
C O N T R A S T A G E N T S......Page 199
T 1 R e l a x a t i o n A g e n t s......Page 200
T 2 R e l a x a t i o n A g e n t s......Page 203
C L I N I C A L A P P L I C A T I O N S......Page 205
G e n e r a l P r i n c i p l e s o f C l i n i c a l M a g n e t i c......Page 206
E x a m i n a t i o n D e s i g n C o n s i d e r a t i o n s......Page 207
P r o t o c o l C o n s i d e r a t i o n s f o r A n a t o m i c a l......Page 208
H e a r t a n d G r e a t V e s s e l s......Page 209
L i v e r......Page 211
P e l v i s......Page 215
S p o i l e d G r a d i e n t E c h o......Page 217
F a t S a t u r a t i o n......Page 218
E c h o T r a i n S p i n E c h o......Page 219
S e d a t e d o r A g i t a t e d P a t i e n t s......Page 220
R E F E R E N C E S......Page 221
3 - I n t e r v e n t i o n a l C o m p u t e d T o m o g r a p h y......Page 223
P a u l L . M o l i n a......Page 224
P E R C U T A N E O U S B I O P S Y......Page 227
N e e d l e S e l e c t i o n......Page 229
A s p i r a t i o n N e e d l e s......Page 230
C u t t i n g N e e d l e s......Page 231
A u t o m a t e d N e e d l e D e v i c e s......Page 233
T e c h n i q u e......Page 235
T a n d e m - N e e d l e a n d C o a x i a l - N e e d l e T e c h n i......Page 241
C T F l u o r o s c o p y......Page 243
A n g l e d B i o p s y......Page 245
C o m p l i c a t i o n s......Page 247
L u n g a n d M e d i a s t i n u m......Page 248
L i v e r......Page 255
P a n c r e a s......Page 256
A d r e n a l G l a n d......Page 259
K i d n e y......Page 262
R e t r o p e r i t o n e u m......Page 264
P e l v i s......Page 266
P a r a t h y r o i d G l a n d s......Page 267
A b s c e s s D r a i n a g e......Page 270
A c c e s s R o u t e......Page 271
C a t h e t e r S e l e c t i o n......Page 272
C a t h e t e r P l a c e m e n t......Page 274
M a n a g e m e n t......Page 275
R e s u l t s a n d C o m p l i c a t i o n s......Page 278
L u n g a n d M e d i a s t i n u m......Page 280
L i v e r......Page 281
P a n c r e a s......Page 282
K i d n e y......Page 283
P e l v i s......Page 284
P a n c r e a t i c P s e u d o c y s t s......Page 285
C e c o s t o m y......Page 286
N e u r o l y s i s......Page 288
C h e m i c a l A b l a t i o n......Page 291
T h e r m a l A b l a t i o n......Page 293
R A D I O F R E Q U E N C Y A B L A T I O N O F T H E L I V E R I n d......Page 294
P a t i e n t S e l e c t i o n......Page 295
T e c h n i q u e......Page 298
I m a g i n g F o l l o w - U p......Page 299
R e s u l t s......Page 300
C o m p l i c a t i o n s......Page 301
T U M O R A B L A T I O N I N O T H E R L O C A T I O N S L u n g......Page 302
K i d n e y......Page 304
B o n e......Page 307
R e f e r e n c e s......Page 311
4 - N e c k......Page 343
C o m p u t e d T o m o g r a p h y......Page 344
M a g n e t i c R e s o n a n c e I m a g i n g......Page 347
C o m p a r i s o n o f C o m p u t e d T o m o g r a p h y a n d M a......Page 353
A N A T O M Y......Page 355
C e r v i c a l T r i a n g l e s......Page 356
C e r v i c a l S p a c e s......Page 357
S U B L I N G U A L S P A C E......Page 358
S U B M A N D I B U L A R S P A C E......Page 360
P A R O T I D S P A C E......Page 362
P A R A P H A R Y N G E A L S P A C E......Page 371
C A R O T I D S P A C E......Page 373
M A S T I C A T O R S P A C E......Page 376
P H A R Y N G E A L M U C O S A L S P A C E......Page 379
V I S C E R A L S P A C E......Page 386
L a r y n x a n d H y p o p h a r y n x......Page 387
T h e H y o i d B o n e a n d L a r y n g e a l C a r t i l a g e s......Page 388
L a r y n g e a l L i g a m e n t s a n d M e m b r a n e s......Page 392
L a r y n g e a l M u s c l e s......Page 396
S p a c e s w i t h i n t h e L a r y n x......Page 399
M u c o s a l S u r f a c e s o f t h e L a r y n x......Page 400
H y p o p h a r y n x......Page 401
A i r w a y......Page 403
P a t h o l o g y o f t h e L a r y n x a n d H y p o p h a r y n x......Page 404
S u p r a g l o t t i c C a r c i n o m a......Page 406
G l o t t i c C a r c i n o m a......Page 409
S u b g l o t t i c C a r c i n o m a......Page 413
H y p o p h a r y n g e a l C a r c i n o m a......Page 415
S p e c i a l I s s u e s i n C a n c e r o f t h e L a r y n x......Page 417
B e n i g n M u c o s a l D i s e a s e o f t h e L a r y n x a n......Page 424
S u b m u c o s a l D i s e a s e o f t h e L a r y n x a n d H y p......Page 425
O t h e r C o n d i t i o n s o f t h e L a r y n x a n d H y p o......Page 429
T h y r o i d......Page 431
P a r a t h y r o i d......Page 441
R E T R O P H A R Y N G E A L S P A C E......Page 445
P O S T E R I O R C E R V I C A L S P A C E......Page 447
P E R I V E R T E B R A L S P A C E......Page 450
L Y M P H N O D E S O F T H E N E C K A n a t o m y......Page 451
P a t h o l o g y......Page 460
C Y S T I C N E C K L E S I O N S......Page 468
P O S T T R E A T M E N T N E C K......Page 485
R E F E R E N C E S......Page 502
5 - T h o r a x : T e c h n i q u e s a n d N o r m a l A n a t o m......Page 535
S a n j e e v B h a l l a......Page 536
I N D I C A T I O N S......Page 540
C O M P U T E D T O M O G R A P H Y A N D M A G N E T I C R E S O N A N......Page 544
H e l i c a l / S p i r a l C T......Page 547
C o m p u t e d T o m o g r a p h y S c a n P a r a m e t e r s S e l e......Page 548
S c a n C o l l i m a t i o n......Page 549
I n t e r s l i c e S p a c i n g / R e c o n s t r u c t i o n I n t e r......Page 550
P i t c h......Page 551
F i e l d o f V i e w......Page 552
R a d i a t i o n D o s e......Page 553
C o m p u t e d T o m o g r a p h y P a r a m e t e r s f o r V i e w......Page 554
C T I n t r a v e n o u s C o n t r a s t A d m i n i s t r a t i o n......Page 555
C T S P E C I A L T E C H N I Q U E S H i g h - R e s o l u t i o n C o......Page 559
T h i n - S e c t i o n C o m p u t e d T o m o g r a p h y I m a g i n......Page 566
T w o - D i m e n s i o n a l M u l t i p l a n a r R e f o r m a t i o n......Page 569
H e l i c a l C T A n g i o g r a p h y......Page 575
A i r w a y I m a g i n g......Page 577
T h e T h o r a c i c M R E x a m i n a t i o n G e n e r a l......Page 579
R e s p i r a t o r y G a t i n g......Page 580
C a r d i a c M o t i o n......Page 582
C o n t r a s t A g e n t s......Page 583
S p e c i f i c U s e s......Page 584
M a g n e t i c R e s o n a n c e A r t i f a c t s i n t h e C h e......Page 585
C T A r t i f a c t s......Page 588
N O R M A L T H O R A C I C A N A T O M Y A N D A N A T O M I C A L V......Page 589
T h o r a c i c A n a t o m y......Page 590
T h o r a c i c I n l e t a n d S t e r n o c l a v i c u l a r J u n......Page 591
C r o s s i n g L e f t B r a c h i o c e p h a l i c V e i n ( F i g......Page 594
A o r t i c A r c h ( F i g . 5 - 3 2 )......Page 595
L e f t P u l m o n a r y A r t e r y......Page 599
L e f t A t r i u m ( F i g . 5 - 3 7 )......Page 600
C a r d i a c V e n t r i c l e s ( F i g . 5 - 3 8 )......Page 605
S p e c i f i c A n a t o m i c S t r u c t u r e s B r a c h i a l P l......Page 608
C h e s t W a l l......Page 610
P u l m o n a r y P a r e n c h y m a......Page 614
T h e A i r w a y s......Page 617
T r a c h e a......Page 627
E s o p h a g u s......Page 628
T h y m u s ( F i g . 5 - 5 1 )......Page 630
A z y g o s V e n o u s S y s t e m......Page 633
M e d i a s t i n a l L y m p h N o d e s......Page 636
P l e u r a a n d P e r i c a r d i u m......Page 637
P l e u r a......Page 638
T A B L E 5 - 1 M O D I F I E D A M E R I C A N T H O R A C I C S O......Page 640
1 0 R......Page 641
N o d a l S t a t i o n s......Page 642
P e r i c a r d i u m......Page 648
T h e A n t e r i o r J u n c t i o n L i n e......Page 653
D i a p h r a g m......Page 654
N O R M A L V A R I A N T S......Page 658
C o n g e n i t a l A b s e n c e......Page 659
M e d i a s t i n a l V a s c u l a r A n o m a l i e s......Page 660
A r t e r i a l A n o m a l i e s......Page 668
V a s c u l a r : A o r t i c......Page 673
R E F E R E N C E S......Page 674
6 - M e d i a s t i n u m......Page 695
T h y m o m a......Page 696
G e r m C e l l T u m o r s......Page 706
T h y m i c L y m p h o m a......Page 712
T h y m i c N e u r o e n d o c r i n e T u m o r s......Page 715
T h y m i c C a r c i n o m a......Page 716
T h y m o l i p o m a......Page 718
T h y m i c C y s t......Page 720
R e b o u n d T h y m i c H y p e r p l a s i a......Page 723
C O N G E N I T A L M E D I A S T I N A L C Y S T S......Page 726
B r o n c h o g e n i c C y s t......Page 727
E s o p h a g e a l D u p l i c a t i o n C y s t......Page 732
P e r i c a r d i a l C y s t......Page 733
D i f f e r e n t i a l D i a g n o s i s......Page 735
T u m o r s o f A d i p o s e T i s s u e L i p o m a s......Page 742
L i p o s a r c o m a......Page 743
D i f f e r e n t i a l D i a g n o s i s......Page 744
T u m o r s o f V a s c u l a r / L y m p h a t i c T i s s u e H e m a......Page 746
L y m p h a t i c M a l f o r m a t i o n s......Page 750
N E U R O G E N I C T U M O R S......Page 753
T u m o r s o f P e r i p h e r a l N e r v e s......Page 754
T u m o r s o f S y m p a t h e t i c G a n g l i a......Page 758
T u m o r s o f P a r a g a n g l i o n C e l l s......Page 761
M I S C E L L A N E O U S P A R A S P I N A L M A S S E S......Page 764
V e r t e b r a l A b n o r m a l i t i e s......Page 765
E s o p h a g e a l L e s i o n s......Page 766
A C U T E M E D I A S T I N I T I S A N D M E D I A S T I N A L A B S C......Page 767
M E D I A S T I N A L A N D H I L A R L Y M P H A D E N O P A T H Y......Page 769
M e d i a s t i n a l L y m p h a d e n o p a t h y......Page 770
H i l a r L y m p h a d e n o p a t h y......Page 772
D i f f e r e n t i a l D i a g n o s i s......Page 775
L o w - A t t e n u a t i o n L y m p h N o d e s......Page 776
E n h a n c i n g L y m p h N o d e s......Page 777
M a g n e t i c R e s o n a n c e I m a g i n g o f M e d i a s t i n......Page 782
T u b e r c u l o s i s......Page 784
H i s t o p l a s m o s i s......Page 787
S a r c o i d o s i s......Page 790
M e t a s t a s e s......Page 791
H o d g k i n D i s e a s e......Page 793
M a g n e t i c R e s o n a n c e I m a g i n g o f L y m p h o m a......Page 795
P o s t t r e a t m e n t F o l l o w - u p......Page 796
A o r t i c A t h e r o s c l e r o s i s......Page 800
A n e u r y s m A s s o c i a t e d w i t h I n h e r i t e d F i b r i......Page 802
M y c o t i c A n e u r y s m......Page 803
A o r t i t i s A s s o c i a t e d w i t h A n e u r y s m......Page 804
P o s t t r a u m a t i c A n e u r y s m......Page 805
C l i n i c a l P r e s e n t a t i o n a n d M a n a g e m e n t......Page 806
C o m p u t e d T o m o g r a p h y......Page 807
M a g n e t i c R e s o n a n c e I m a g i n g......Page 814
P o s t t r e a t m e n t E v a l u a t i o n......Page 822
A c u t e A o r t i c S y n d r o m e s......Page 825
A o r t i c D i s s e c t i o n......Page 826
C l i n i c a l F i n d i n g s......Page 827
P a t h o g e n e s i s......Page 828
C l a s s i f i c a t i o n......Page 830
T r e a t m e n t......Page 831
D i a g n o s i s......Page 835
A o r t o g r a p h y......Page 836
C o m p u t e d T o m o g r a p h y......Page 837
M a g n e t i c R e s o n a n c e I m a g i n g......Page 843
E c h o c a r d i o g r a p h y......Page 848
I n t r a m u r a l H e m a t o m a......Page 849
I m a g i n g F i n d i n g s a n d P i t f a l l s......Page 850
P e n e t r a t i n g A t h e r o s c l e r o t i c U l c e r......Page 854
P o s t t r e a t m e n t E v a l u a t i o n......Page 858
A o r t i c C o a r c t a t i o n......Page 861
P s e u d o c o a r c t a t i o n......Page 863
T a k a y a s u A r t e r i t i s......Page 864
C E N T R A L T H O R A C I C V E I N S......Page 868
V e n o u s O b s t r u c t i o n......Page 870
C o m p u t e d T o m o g r a p h y......Page 872
V e n o u s A n e u r y s m......Page 873
T R A C H E A......Page 874
F o c a l T r a c h e a l N a r r o w i n g B e n i g n N o n n e o p l......Page 877
B e n i g n N e o p l a s m s......Page 879
M a l i g n a n t N e o p l a s m s......Page 880
D i f f u s e T r a c h e a l N a r r o w i n g......Page 882
T r a c h e o m a l a c i a......Page 883
S a b e r - S h e a t h T r a c h e a......Page 884
R e l a p s i n g P o l y c h o n d r i t i s......Page 885
A m y l o i d o s i s......Page 886
W e g e n e r G r a n u l o m a t o s i s......Page 887
D i f f u s e T r a c h e a l W i d e n i n g T r a c h e o b r o n c h o......Page 889
A c q u i r e d T r a c h e o m e g a l y......Page 890
R E F E R E N C E S......Page 891
7 - L u n g......Page 927
T r a c h e a l D i s e a s e s......Page 928
T A B L E 7 - 1 D I S E A S E S O F T H E T R A C H E A......Page 929
F o c a l......Page 930
B r o n c h i......Page 933
в Ђ њ B r o n c h i a l A d e n o m a в Ђ ќ......Page 939
B r o n c h o g e n i c C a r c i n o m a......Page 942
S t a g i n g......Page 946
D i s t a n t M e t a s t a s i s ( M ) :......Page 957
5 - Y e a r S u r v i v a l ( % )......Page 958
L u n g C a n c e r S c r e e n i n g......Page 992
P u l m o n a r y C o l l a p s e......Page 1000
G e n e r a l O b s e r v a t i o n s......Page 1002
R i g h t U p p e r L o b e C o l l a p s e......Page 1004
R i g h t M i d d l e L o b e C o l l a p s e......Page 1005
L o w e r L o b e C o l l a p s e......Page 1007
R o l e o f M a g n e t i c R e s o n a n c e I m a g i n g i n P......Page 1008
C o m p r e s s i v e A t e l e c t a s i s......Page 1009
R o u n d e d A t e l e c t a s i s......Page 1011
B r o n c h i e c t a s i s......Page 1015
P U L M O N A R Y P A R E N C H Y M A......Page 1025
S o l i t a r y P u l m o n a r y N o d u l e......Page 1026
F o c a l L u n g L e s i o n s......Page 1036
P u l m o n a r y A r t e r i o v e n o u s M a l f o r m a t i o n s......Page 1038
P u l m o n a r y S e q u e s t r a t i o n......Page 1042
O t h e r F o c a l L e s i o n s......Page 1045
O c c u l t P u l m o n a r y M e t a s t a s e s......Page 1052
O t h e r O c c u l t P u l m o n a r y P r o c e s s e s......Page 1057
R a d i a t i o n - I n d u c e d P u l m o n a r y I n j u r y......Page 1058
D i f f e r e n t i a t i o n o f P o s t r a d i a t i o n C h a n g e......Page 1061
P u l m o n a r y E m b o l i s m......Page 1062
T e c h n i q u e......Page 1065
I n t e r p r e t a t i o n ( A n a l y s i s )......Page 1066
A c c u r a c y ( R e s u l t s )......Page 1086
R o l e......Page 1091
D i f f u s e L u n g D i s e a s e......Page 1094
H i g h - R e s o l u t i o n C o m p u t e d T o m o g r a p h y T e c......Page 1096
P r o n e V e r s u s S u p i n e P o s i t i o n i n g......Page 1098
R e c o n s t r u c t i o n A l g o r i t h m s......Page 1099
G l o b a l D i s t r i b u t i o n......Page 1101
B r o n c h o v a s c u l a r D i s t r i b u t i o n......Page 1102
I n t e r s t i t i a l P a t t e r n s......Page 1103
S e p t a l T h i c k e n i n g......Page 1104
H o n e y c o m b i n g , P a r e n c h y m a l B a n d s , a n d S u b......Page 1105
A i r s p a c e P a t t e r n s......Page 1107
D e c r e a s e d L u n g A t t e n u a t i o n C y s t i c A i r s p a......Page 1108
A i r T r a p p i n g......Page 1109
P u l m o n a r y N o d u l e s......Page 1110
S p e c i f i c D i s e a s e P r o c e s s e s P u l m o n a r y E d e......Page 1111
A d u l t R e s p i r a t o r y D i s t r e s s S y n d r o m e......Page 1112
U s u a l I n t e r s t i t i a l P n e u m o n i a......Page 1113
N o n s p e c i f i c I n t e r s t i t i a l P n e u m o n i a......Page 1115
R e s p i r a t o r y B r o n c h i o l i t i s в Ђ “ I n t e r s t i t i a......Page 1117
A c u t e I n t e r s t i t i a l P n e u m o n i a......Page 1119
O r g a n i z i n g P n e u m o n i a......Page 1120
C o n n e c t i v e T i s s u e / C o l l a g e n V a s c u l a r D i s......Page 1122
S c l e r o d e r m a......Page 1123
D r u g - I n d u c e d L u n g D i s e a s e......Page 1124
S a r c o i d o s i s......Page 1125
S i l i c o s i s......Page 1130
A s b e s t o s i s......Page 1132
W e g e n e r G r a n u l o m a t o s i s......Page 1134
L y m p h a n g i o l e i o m y o m a t o s i s a n d T u b e r o u s S c......Page 1136
H i s t i o c y t o s i s X ( L a n g e r h a n s C e l l H i s t i o......Page 1137
H y p e r s e n s i t i v i t y P n e u m o n i t i s ( E x t r i n s i c......Page 1139
E o s i n o p h i l i c L u n g D i s e a s e......Page 1140
P u l m o n a r y A l v e o l a r P r o t e i n o s i s......Page 1141
L y m p h a n g i t i c C a r c i n o m a......Page 1143
P u l m o n a r y E m p h y s e m a......Page 1144
C e n t r i l o b u l a r E m p h y s e m a......Page 1145
P a n l o b u l a r E m p h y s e m a......Page 1147
P a r a s e p t a l E m p h y s e m a......Page 1148
L u n g V o l u m e R e d u c t i o n S u r g e r y......Page 1149
S m a l l A i r w a y D i s e a s e B r o n c h i o l i t i s......Page 1151
C o n s t r i c t i v e ( O b l i t e r a t i v e ) B r o n c h i o l i t......Page 1152
P r o l i f e r a t i v e B r o n c h i o l i t i s......Page 1153
P u l m o n a r y L y m p h o i d D i s o r d e r s......Page 1154
P u l m o n a r y I n f e c t i o n s......Page 1155
M y c o b a c t e r i a l......Page 1156
A s p e r g i l l u s......Page 1158
L u n g A b s c e s s......Page 1161
A I D S......Page 1163
L u n g T r a n s p l a n t a t i o n......Page 1167
R E F E R E N C E S......Page 1170
8 - P l e u r a , C h e s t W a l l , a n d D i a p h r a g m......Page 1221
A n a t o m y......Page 1222
I n t e r l o b a r F i s s u r e s......Page 1223
A c c e s s o r y F i s s u r e s......Page 1224
I n f e r i o r P u l m o n a r y L i g a m e n t......Page 1226
P L E U R A L D I S E A S E......Page 1228
F l u i d T y p e s a n d C a u s e s......Page 1231
C o m p u t e d T o m o g r a p h y F i n d i n g s A t t e n u a t i o n......Page 1233
L o c a t i o n a n d V o l u m e o f F l u i d......Page 1235
D i s t i n g u i s h i n g B e t w e e n P l e u r a l F l u i d a n......Page 1238
E M P Y E M A......Page 1242
E m p y e m a V e r s u s L u n g A b s c e s s......Page 1246
F l u i d i n P r e e x i s t i n g A i r s p a c e s......Page 1250
C h r o n i c E m p y e m a......Page 1252
P L E U R A L T H I C K E N I N G......Page 1254
P l e u r a l C a l c i f i c a t i o n......Page 1260
E x t r a p l e u r a l F a t......Page 1262
A s b e s t o s - R e l a t e d B e n i g n P l e u r a l P r o c e s s......Page 1263
R o u n d e d A t e l e c t a s i s......Page 1270
P N E U M O T H O R A X......Page 1274
T U M O R S O F T H E P L E U R A......Page 1277
L i p o m a......Page 1280
F i b r o u s T u m o r s o f t h e P l e u r a......Page 1282
T h o r a c i c S p l e n o s i s......Page 1286
P l e u r a l L y m p h o m a......Page 1290
M a l i g n a n t M e s o t h e l i o m a......Page 1291
O t h e r P r i m a r y P l e u r a l N e o p l a s m s......Page 1301
P L E U R O D E S I S......Page 1302
P O S T P N E U M O N E C T O M Y S P A C E......Page 1304
C H E S T W A L L......Page 1307
S t e r n u m a n d C l a v i c l e s......Page 1310
P e c t u s D e f o r m i t i e s......Page 1315
S t e r n o c l a v i c u l a r D i s l o c a t i o n......Page 1316
R i b s......Page 1317
C H E S T W A L L I N F E C T I O N......Page 1320
E m p y e m a N e c e s s i t a t i s......Page 1323
T U M O R S O F T H E C H E S T W A L L......Page 1324
B o n e T u m o r s......Page 1327
B e n i g n B o n e T u m o r s......Page 1328
M a l i g n a n t B o n e T u m o r s......Page 1331
S o f t T i s s u e T u m o r s......Page 1334
B e n i g n S o f t T i s s u e T u m o r s......Page 1336
M a l i g n a n t S o f t T i s s u e T u m o r s......Page 1342
C h e s t W a l l I n v a s i o n......Page 1345
B R E A S T......Page 1348
P o s t t h e r a p y E v a l u a t i o n......Page 1354
B r e a s t C a n c e r R e c u r r e n c e......Page 1357
B r e a s t I m p l a n t s......Page 1358
A X I L L A......Page 1359
B R A C H I A L P L E X U S......Page 1361
C A R D I O T H O R A C I C S U R G E R Y P r e o p e r a t i v e P l a n......Page 1369
M e d i a n S t e r n o t o m y......Page 1370
D I A P H R A G M......Page 1372
D i a p h r a g m a t i c C r u r a......Page 1373
D i a p h r a g m a t i c P s e u d o t u m o r s......Page 1374
D I A P H R A G M A T I C H E R N I A S C o n g e n i t a l D i a p h r a......Page 1375
M o r g a g n i H e r n i a......Page 1378
A c q u i r e d D i a p h r a g m a t i c H e r n i a s H i a t a l H e......Page 1379
T r a u m a t i c H e r n i a......Page 1380
S U P E R I O R D I A P H R A G M A T I C L Y M P H N O D E S......Page 1388
D I A P H R A G M M O T I O N......Page 1393
R E F E R E N C E S......Page 1394
9 - H e a r t a n d P e r i c a r d i u m......Page 1431
T E C H N I Q U E......Page 1432
I m a g e A c q u i s i t i o n a n d T e c h n i q u e C a r d i a c......Page 1433
T e m p o r a l R e s o l u t i o n......Page 1435
T A B L E 9 - 1 C A R D I A C M D C T S C A N P R O T O C O L S (......Page 1436
C o r o n a r y C T A......Page 1437
R a d i a t i o n D o s e a n d M e t h o d s o f R e d u c t i o n......Page 1439
I m a g e P o s t p r o c e s s i n g a n d I n t e r p r e t a t i o n......Page 1440
C a r d i a c M R......Page 1445
P u l s e S e q u e n c e s......Page 1446
I m a g e P l a n e s......Page 1449
C o r o n a l a n d S a g i t t a l P l a n e s......Page 1450
V e r t i c a l L o n g - A x i s P l a n e ( T w o - C h a m b e r V......Page 1452
H o r i z o n t a l L o n g - A x i s P l a n e ( F o u r - C h a m b e......Page 1453
S h o r t - A x i s P l a n e......Page 1454
A o r t i c O u t f l o w L o n g - A x i s V i e w......Page 1455
P E R F O R M A N C E O F S P E C I F I C T Y P E S O F E X A M I N A......Page 1456
C o r o n a r y C T A n g i o g r a p h y......Page 1457
T A B L E 9 - 2 O V E R A L L D E T E C T I O N ( P E R P A T I E N......Page 1458
C o r o n a r y M R A n g i o g r a p h y ( M R A ) M e t h o d s......Page 1459
S p e c i f i c i t y в Ђ > 5 0 % o r в ‰ Ґ 5 0 % n / N ( % )......Page 1460
R e c o m m e n d a t i o n......Page 1463
C o r o n a r y A r t e r y D i s e a s e A s s e s s m e n t......Page 1464
C T A s s e s s m e n t o f M y o c a r d i a l F u n c t i o n......Page 1465
M R A s s e s s m e n t o f M y o c a r d i a l F u n c t i o n ( 1......Page 1467
T A B L E 9 - 5 S T R E S S P R O T O C O L S......Page 1469
I m a g e I n t e r p r e t a t i o n......Page 1470
C a l c u l a t i o n o f L V V o l u m e s a n d E F......Page 1471
M R I......Page 1473
C T......Page 1475
C T a n d M R I o f O t h e r C a r d i a c D i s e a s e......Page 1476
G e n e r a l M R P r o t o c o l f o r C H D......Page 1478
C o n t r a s t - E n h a n c e d M R A......Page 1479
I n t r a c a r d i a c S h u n t s......Page 1480
T e t r a l o g y o f F a l l o t ( T O F )......Page 1481
A n o m a l o u s P u l m o n a r y V e i n s......Page 1485
P u l m o n a r y V e i n M a p p i n g ( 1 3 7 )......Page 1486
C a r d i o m y o p a t h i e s......Page 1489
R i g h t V e n t r i c u l a r D y s p l a s i a......Page 1491
P e r i c a r d i a l D i s e a s e......Page 1494
C o n s t r i c t i v e P e r i c a r d i t i s......Page 1495
P e r i c a r d i a l E f f u s i o n s......Page 1497
C o n g e n i t a l A b s e n c e o f t h e P e r i c a r d i u m......Page 1498
P e r i c a r d i a l C y s t s......Page 1499
T u m o r s......Page 1500
V a l v u l a r D i s e a s e......Page 1505
A n o m a l o u s C o r o n a r y A r t e r i e s......Page 1507
R E F E R E N C E S......Page 1508
1 0 - N o r m a l A b d o m i n a l a n d P e l v i c A n a t o m y......Page 1521
C h r i s t i n e P e t e r s o n......Page 1522
A B D O M I N A L A N A T O M Y A b d o m i n a l W a l l......Page 1523
D i a p h r a g m , C r u r a , a n d A r c u a t e L i g a m e n t s......Page 1535
I n t r a p e r i t o n e a l O r g a n s E m b r y o l o g y......Page 1545
P e r i t o n e a l S p a c e s......Page 1551
E x t r a p e r i t o n e a l O r g a n s , S p a c e s , a n d P l a......Page 1554
G r e a t V e s s e l S p a c e......Page 1555
P s o a s S p a c e s......Page 1563
K i d n e y s a n d P e r i r e n a l S p a c e s......Page 1567
P o s t e r i o r P a r a r e n a l S p a c e......Page 1572
A n t e r i o r P a r a r e n a l S p a c e......Page 1573
P a n c r e a s , D u o d e n u m , a n d M e s e n t e r i c R o o t......Page 1576
A s c e n d i n g a n d D e s c e n d i n g C o l o n......Page 1582
D i s t r i b u t i o n o f F l u i d i n t h e A n t e r i o r P......Page 1585
M a j o r M u s c u l o s k e l e t a l L a n d m a r k s......Page 1589
N e u r o a n a t o m y......Page 1593
V a s c u l a r A n a t o m y......Page 1594
P e l v i c P e r i t o n e a l S p a c e s......Page 1595
E x t r a p e r i t o n e a l S p a c e s......Page 1597
D i s t i n c t i v e F e a t u r e s o f t h e M a l e P e l v i s......Page 1600
M a l e P e r i n e u m......Page 1603
F e m a l e P e r i n e u m......Page 1621
1 1 - G a s t r o i n t e s t i n a l T r a c t......Page 1637
N o r m a l A n a t o m y......Page 1638
T e c h n i q u e......Page 1639
C o n g e n i t a l A b n o r m a l i t i e s......Page 1640
N e o p l a s i a......Page 1641
B e n i g n T u m o r s......Page 1642
T N M......Page 1645
P r e s e n t D i s t a n t M e t a s t a s i s ( M )......Page 1646
M i s c e l l a n e o u s C o n d i t i o n s......Page 1649
S T O M A C H......Page 1656
T e c h n i q u e......Page 1657
C o n g e n i t a l A b n o r m a l i t i e s......Page 1660
G a s t r o i n t e s t i n a l S t r o m a l T u m o r s......Page 1661
M a l i g n a n t T u m o r s......Page 1663
M i s c e l l a n e o u s......Page 1670
T e c h n i q u e......Page 1677
C o n g e n i t a l A b n o r m a l i t i e s......Page 1679
G a s t r o i n t e s t i n a l S t r o m a l T u m o r s......Page 1682
B e n i g n T u m o r s......Page 1683
S m a l l B o w e l O b s t r u c t i o n......Page 1687
C l o s e d - L o o p O b s t r u c t i o n a n d I s c h e m i a......Page 1692
I n f l a m m a t i o n......Page 1701
N o n i n f l a m m a t o r y E d e m a......Page 1707
M i s c e l l a n e o u s......Page 1708
N o r m a l A n a t o m y......Page 1712
T e c h n i q u e......Page 1714
B e n i g n T u m o r s......Page 1715
M a l i g n a n t T u m o r s......Page 1717
D u k e s S t a g e......Page 1720
I n f l a m m a t i o n......Page 1725
M i s c e l l a n e o u s......Page 1734
C T C o l o n o g r a p h y......Page 1736
R E F E R E N C E S......Page 1739
1 2 - L i v e r......Page 1761
G r o s s M o r p h o l o g y......Page 1762
T A B L E 1 2 - 1 A N A T O M I C S E G M E N T S O F T H E L I V......Page 1768
V a s c u l a r A n a t o m y......Page 1770
H e p a t i c P a r e n c h y m a......Page 1772
A n a t o m i c V a r i a n t s a n d A n o m a l i e s......Page 1773
C O M P U T E D T O M O G R A P H Y I M A G E A C Q U I S I T I O N C O......Page 1774
P R I N C I P L E S O F H E P A T I C C O N T R A S T E N H A N C E M E......Page 1775
T i m i n g o f H e p a t i c E n h a n c e m e n t......Page 1778
I M A G I N G T E C H N I Q U E S C o m p u t e d T o m o g r a p h y W......Page 1780
M u l t i p h a s e H e p a t i c C o m p u t e d T o m o g r a p h y......Page 1781
A n g i o g r a p h y - A s s i s t e d C o m p u t e d T o m o g r a p h......Page 1783
M a g n e t i c R e s o n a n c e I m a g i n g......Page 1784
C o n t r a s t - E n h a n c e d M a g n e t i c R e s o n a n c e I m......Page 1787
B E N I G N H E P A T I C T U M O R S C y s t s D e v e l o p m e n t a......Page 1789
P o l y c y s t i c L i v e r D i s e a s e......Page 1791
B i l i a r y H a m a r t o m a s......Page 1792
H e m a n g i o m a......Page 1794
F o c a l N o d u l a r H y p e r p l a s i a......Page 1802
H e p a t o c e l l u l a r A d e n o m a......Page 1809
R a r e B e n i g n T u m o r s......Page 1816
M A L I G N A N T H E P A T I C T U M O R S H e p a t o c e l l u l a r......Page 1818
F i b r o l a m e l l a r H e p a t o c e l l u l a r C a r c i n o m a......Page 1838
I n t r a h e p a t i c C h o l a n g i o c a r c i n o m a......Page 1841
M e t a s t a s e s......Page 1845
R a r e M a l i g n a n t T u m o r s......Page 1854
P e r c u t a n e o u s T u m o r A b l a t i o n a n d C r y o s u r......Page 1861
P y o g e n i c A b s c e s s e s......Page 1867
N o n p y o g e n i c A b s c e s s e s A m e b i c A b s c e s s......Page 1872
F u n g a l M i c r o a b s c e s s e s......Page 1874
E c h i n o c o c c a l D i s e a s e......Page 1876
U n c o m m o n H e p a t i c I n f e c t i o n s......Page 1878
S t e a t o s i s......Page 1879
C i r r h o s i s......Page 1884
I r o n O v e r l o a d......Page 1891
H e p a t i t i s......Page 1896
R a d i a t i o n I n j u r y......Page 1897
S a r c o i d o s i s......Page 1899
S t o r a g e D i s o r d e r s......Page 1901
O t h e r D i f f u s e D i s o r d e r s......Page 1902
V A S C U L A R D I S O R D E R S P o r t a l V e i n T h r o m b o s i......Page 1903
B u d d - C h i a r i S y n d r o m e......Page 1907
P a s s i v e H e p a t i c C o n g e s t i o n......Page 1912
H e p a t i c I n f a r c t i o n......Page 1913
P e l i o s i s H e p a t i s......Page 1914
L I V E R T R A N S P L A N T A T I O N P r e t r a n s p l a n t E v a l......Page 1917
P o s t t r a n s p l a n t C o m p l i c a t i o n s......Page 1919
R E F E R E N C E S......Page 1921
1 3 - T h e B i l i a r y T r a c t......Page 1991
T h e B i l i a r y T r a c t......Page 1992
N O R M A L A N A T O M Y A N D V A R I A T I O N S......Page 1993
P A T H O P H Y S I O L O G Y O F B I L I A R Y O B S T R U C T I O N......Page 1994
G E N E R A L P R I N C I P L E S O F B I L I A R Y I M A G I N G......Page 1995
C O M P U T E D T O M O G R A P H Y : T E C H N I Q U E A N D N O R M A......Page 1997
M A G N E T I C R E S O N A N C E I M A G I N G : T E C H N I Q U E A N......Page 2005
L i m i t a t i o n s o f M a g n e t i c R e s o n a n c e C h o l a n......Page 2008
C O N G E N I T A L A B N O R M A L I T I E S A N D D I S E A S E S O F......Page 2009
D i s e a s e s o f t h e G a l l b l a d d e r C h o l e l i t h i a s......Page 2010
I m a g i n g o f C h o l e l i t h i a s i s a n d S l u d g e......Page 2011
C o m p u t e d T o m o g r a p h y a n d M a g n e t i c R e s o n a......Page 2012
I m a g i n g o f C h o l e c y s t i t i s......Page 2016
G a l l b l a d d e r P o l y p s......Page 2022
A d e n o m y o m a t o s i s......Page 2023
G a l l b l a d d e r C a r c i n o m a......Page 2025
C o m p u t e d T o m o g r a p h y o f G a l l b l a d d e r C a r c......Page 2027
C O N G E N I T A L A B N O R M A L I T I E S A N D D I S E A S E S O F......Page 2029
C a r o l i D i s e a s e......Page 2031
C h o l e d o c h o l i t h i a s i s......Page 2034
C h o l a n g i t i s......Page 2036
R e c u r r e n t P y o g e n i c H e p a t i t i s......Page 2038
P r i m a r y S c l e r o s i n g C h o l a n g i t i s......Page 2040
I m a g i n g o f P r i m a r y S c l e r o s i n g C h o l a n g i t......Page 2043
M a g n e t i c R e s o n a n c e I m a g i n g o f P r i m a r y S c......Page 2044
C h o l a n g i o c a r c i n o m a......Page 2046
C l i n i c a l A s p e c t s a n d C l a s s i f i c a t i o n o f C......Page 2047
G r o w t h P a t t e r n s a n d A p p r o a c h t o D i a g n o s......Page 2048
C o m p u t e d T o m o g r a p h y o f C h o l a n g i o c a r c i n o......Page 2049
U n u s u a l B i l e D u c t T u m o r s......Page 2053
N o n b i l i a r y T u m o r s T h a t A f f e c t t h e B i l i a......Page 2054
B i l i a r y T r a c t S u r g e r y L i v e r T r a n s p l a n t E......Page 2055
L i v i n g D o n o r L i v e r T r a n s p l a n t a t i o n / S e g m......Page 2057
P o s t o p e r a t i v e B i l i a r y C o m p l i c a t i o n s......Page 2059
L i v e r T r a n s p l a n t C o m p l i c a t i o n s......Page 2061
L i v i n g D o n o r T r a n s p l a n t C o m p l i c a t i o n s......Page 2064
A s s e s s m e n t o f B i l i a r y S t e n t s a n d D r a i n s......Page 2065
P o s t в Ђ “ W h i p p l e P r o c e d u r e A s s e s s m e n t......Page 2068
R E F E R E N C E S......Page 2069
1 4 - S p l e e n......Page 2091
S p l e e n......Page 2092
U S E O F C O N T R A S T M A T E R I A L......Page 2093
M A G N E T I C R E S O N A N C E I M A G I N G......Page 2095
S P L E N I C S I Z E......Page 2097
S p l e n i c L o b u l a t i o n......Page 2100
в Ђ њ W a n d e r i n g в Ђ ќ S p l e e n......Page 2102
A c c e s s o r y S p l e e n s......Page 2103
P o l y s p l e n i a......Page 2106
P o l y s p l e n i a ( l e f t i s o m e r i s m )......Page 2107
A s p l e n i a......Page 2108
S p l e n i c в Ђ “ G o n a d a l F u s i o n......Page 2109
E c h i n o c o c c a l C y s t s......Page 2110
P o s t t r a u m a t i c C y s t s......Page 2112
O t h e r C y s t i c L e s i o n s......Page 2113
L i t t o r a l C e l l A n g i o m a......Page 2115
L y m p h a n g i o m a s......Page 2116
S p l e n i c H a m a r t o m a s......Page 2117
E x t r a m e d u l l a r y H e m a t o p o i e s i s......Page 2119
O t h e r B e n i g n S p l e n i c T u m o r s......Page 2120
M a l i g n a n t S p l e n i c T u m o r s L y m p h o m a......Page 2121
A n g i o s a r c o m a s......Page 2126
M e t a s t a t i c D i s e a s e......Page 2128
S p l e n i c I n f e c t i o n......Page 2130
S p l e n i c T r a u m a......Page 2133
M i s c e l l a n e o u s S p l e n i c D i s o r d e r s A m y l o i d o......Page 2134
G a m n a - G a n d y B o d i e s......Page 2135
G a u c h e r D i s e a s e......Page 2136
H e m o c h r o m a t o s i s......Page 2137
P e l i o s i s......Page 2138
S a r c o i d......Page 2139
S i c k l e C e l l A n e m i a......Page 2141
S p l e n i c A r t e r y A n e u r y s m......Page 2142
S p l e n i c I n v o l v e m e n t i n P a n c r e a t i t i s......Page 2143
S p l e n o m e g a l y......Page 2144
S p l e n i c I n f a r c t s......Page 2145
R E F E R E N C E S......Page 2147
1 5 - T h e P a n c r e a s......Page 2173
P A N C R E A S......Page 2174
C o n t r a s t I s s u e s......Page 2175
C o m p u t e d T o m o g r a p h y T e c h n i q u e s......Page 2177
T A B L E 1 5 - 1 M D C T F O R P A N C R E A T I C M A S S......Page 2180
T A B L E 1 5 - 2 S D C T F O R P A N C R E A T I C M A S S a......Page 2181
T A B L E 1 5 - 3 M D C T F O R R O U T I N E A B D O M E N O R......Page 2187
T A B L E 1 5 - 4 S D C T F O R R O U T I N E A B D O M E N O R......Page 2188
N o r m a l A n a t o m y......Page 2190
A n a t o m i c R e l a t i o n s h i p s......Page 2197
D e v e l o p m e n t a l V a r i a n t s a n d A n o m a l i e s......Page 2202
P a t h o l o g i c C o n d i t i o n s N e o p l a s i a A d e n o c a r......Page 2206
T A B L E 1 5 - 5 P A N C R E A T I C T U M O R C L A S S I F I C A T......Page 2207
R e s e c t a b i l i t y o f P a n c r e a t i c T u m o r s......Page 2223
T A B L E 1 5 - 6 P A N C R E A T I C P R O T O N E M I S S I O N T......Page 2227
M u c i n o u s C a r c i n o m a......Page 2243
P a n c r e a t i c N e u r o e n d o c r i n e T u m o r s ( I s l e t......Page 2255
O t h e r N e o p l a s t i c L e s i o n s......Page 2264
I n f l a m m a t o r y D i s e a s e s A c u t e P a n c r e a t i t i s......Page 2273
M i l d A c u t e P a n c r e a t i t i s......Page 2279
C T S e v e r i t y I n d e x i n P a t i e n t s w i t h A c u t......Page 2281
A c u t e F l u i d C o l l e c t i o n s......Page 2288
P a n c r e a t i c A b s c e s s......Page 2291
P a n c r e a t i c N e c r o s i s......Page 2292
I n f e c t e d P a n c r e a t i c N e c r o s i s......Page 2295
P a n c r e a t i c H e m o r r h a g e......Page 2299
C o m p u t e d T o m o g r a p h y G u i d a n c e f o r P a n c r e......Page 2300
M a g n e t i c R e s o n a n c e I m a g i n g i n A c u t e P a n......Page 2301
C h r o n i c P a n c r e a t i t i s......Page 2305
A u t o i m m u n e P a n c r e a t i t i s......Page 2317
P a n c r e a t i c C h a n g e s i n C y s t i c F i b r o s i s......Page 2318
P a n c r e a t i c T r a u m a......Page 2319
P a n c r e a t i c I n f e c t i o n s......Page 2321
P o s t o p e r a t i v e E v a l u a t i o n......Page 2322
P A N C R E A S T R A N S P L A N T A T I O N......Page 2328
R E F E R E N C E S......Page 2331
1 6 - A b d o m i n a l W a l l a n d P e r i t o n e a l C a v i......Page 2359
H e r n i a s......Page 2360
M a s s e s : H e m a t o m a......Page 2362
I n f l a m m a t i o n / I n f e c t i o n......Page 2369
O t h e r N o n n e o p l a s t i c E n t i t i e s......Page 2370
N e o p l a s m s......Page 2371
A n a t o m y......Page 2373
L e f t P e r i t o n e a l S p a c e......Page 2376
R i g h t P e r i h e p a t i c S p a c e......Page 2378
L e s s e r S a c......Page 2380
I n f r a m e s o c o l i c C o m p a r t m e n t......Page 2382
A s c i t e s......Page 2385
I n t r a p e r i t o n e a l A b s c e s s......Page 2393
O t h e r I n t r a p e r i t o n e a l F l u i d C o l l e c t i o n s......Page 2400
T H E M E S E N T E R I E S A N D G R E A T E R O M E N T U M A n a t......Page 2406
P a t h o l o g y o f t h e M e s e n t e r i e s , O m e n t u m ,......Page 2407
E d e m a......Page 2408
C r o h n D i s e a s e......Page 2409
E p i p l o i c A p p e n d a g i t i s......Page 2411
P e r i t o n i t i s......Page 2413
S c l e r o s i n g M e s e n t e r i t i s......Page 2416
M e s e n t e r i c C y s t ( L y m p h a n g i o m a )......Page 2421
O t h e r N o n n e o p l a s t i c P r o c e s s e s o f t h e M e......Page 2424
P r i m a r y N e o p l a s m s o f t h e P e r i t o n e u m......Page 2428
P r i m a r y N e o p l a s m s o f t h e M e s e n t e r y a n d O......Page 2431
S e c o n d a r y N e o p l a s m s......Page 2433
D i r e c t S p r e a d A l o n g P e r i t o n e a l S u r f a c e s......Page 2437
I n t r a p e r i t o n e a l S e e d i n g......Page 2442
L y m p h a t i c D i s s e m i n a t i o n......Page 2447
E m b o l i c M e t a s t a s e s......Page 2453
R E F E R E N C E S......Page 2456
1 7 - R e t r o p e r i t o n e u m......Page 2481
R e t r o p e r i t o n e u m......Page 2482
C o m p u t e d T o m o g r a p h y......Page 2483
M a g n e t i c R e s o n a n c e I m a g i n g......Page 2486
A O R T A......Page 2491
A O R T A в Ђ “ P A T H O L O G I C C O N D I T I O N S A t h e r o s c l e......Page 2493
P e n e t r a t i n g A t h e r o s c l e r o t i c U l c e r a n d I......Page 2495
S t e n o s i s a n d O c c l u s i o n......Page 2496
A o r t i c A n e u r y s m......Page 2498
I n f l a m m a t o r y A A A......Page 2503
M y c o t i c A n e u r y s m......Page 2505
R u p t u r e d A A A......Page 2507
C h r o n i c P s e u d o a n e u r y s m......Page 2510
A o r t o e n t e r i c F i s t u l a......Page 2514
A o r t o c a v a l F i s t u l a......Page 2515
A o r t i c D i s s e c t i o n......Page 2516
A b d o m i n a l A o r t i c A n e u r y s m в Ђ ” S u r g i c a l a n......Page 2525
S u r g i c a l l y P l a c e d A o r t i c G r a f t s : P o s t o p......Page 2528
E n d o g r a f t s : P o s t o p e r a t i v e C o m p l i c a t i o n s......Page 2532
I N F E R I O R V E N A C A V A A N D I T S T R I B U T A R I E S N......Page 2534
N o r m a l V a r i a t i o n s ( C o n g e n i t a l A n o m a l i e s......Page 2537
I n t e r r u p t e d I n f e r i o r V e n a C a v a w i t h A z y g......Page 2539
C i r c u m a o r t i c L e f t R e n a l V e i n......Page 2540
L e f t I n f e r i o r V e n a C a v a......Page 2541
C i r c u m c a v a l U r e t e r ( S y n o n y m , R e t r o c a v a l......Page 2542
O t h e r R a r e A n o m a l i e s......Page 2547
I N F E R I O R V E N A C A V A в Ђ ” P A T H O L O G I C C O N D I T I O......Page 2548
V e n o u s T h r o m b o s i s......Page 2549
I n t r a c a v a l F i l t e r s......Page 2556
O b l i t e r a t i v e H e p a t o c a v o p a t h y ( S y n o n y m , M......Page 2557
P r i m a r y I n f e r i o r V e n a C a v a N e o p l a s m......Page 2558
N o r m a l A n a t o m y......Page 2559
L Y M P H N O D E S в Ђ ” P A T H O L O G I C C O N D I T I O N S L y m p......Page 2561
O t h e r M o d a l i t i e s f o r E v a l u a t i n g L y m p h a d e......Page 2567
D i f f e r e n t i a l D i a g n o s i s......Page 2572
P o s t t h e r a p y E v a l u a t i o n......Page 2573
L y m p h o m a......Page 2574
T e s t i c u l a r N e o p l a s m s......Page 2577
O t h e r R e t r o p e r i t o n e a l M e t a s t a s i s......Page 2581
R E T R O P E R I T O N E A L H E M O R R H A G E......Page 2582
R E T R O P E R I T O N E A L F I B R O S I S......Page 2587
P R I M A R Y R E T R O P E R I T O N E A L T U M O R S......Page 2590
L i p o m a a n d L i p o s a r c o m a......Page 2595
L e i o m y o s a r c o m a......Page 2598
N e u r o g e n i c T u m o r s......Page 2599
P r i m a r y G e r m C e l l T u m o r s......Page 2601
O t h e r R e t r o p e r i t o n e a l T u m o r s......Page 2602
N o r m a l A n a t o m y......Page 2603
N e o p l a s m......Page 2605
I n f l a m m a t o r y L e s i o n s......Page 2606
O t h e r C o n d i t i o n s......Page 2610
1 8 - T h e K i d n e y a n d U r e t e r......Page 2639
A n a t o m y......Page 2640
N o r m a l C o m p u t e d T o m o g r a p h y......Page 2644
C o m p u t e d T o m o g r a p h y T e c h n i q u e......Page 2646
M R I : N O R M A L A P P E A R A N C E A N D T E C H N I Q U E......Page 2650
N o r m a l M a g n e t i c R e s o n a n c e I m a g i n g......Page 2651
M R I T e c h n i q u e......Page 2652
M a g n e t i c R e s o n a n c e I m a g i n g......Page 2653
C O N G E N I T A L A B N O R M A L I T I E S O F T H E K I D N E Y S......Page 2654
A b n o r m a l C o r t i c a l A p p e a r a n c e......Page 2658
R E N A L C A L C I F I C D I S E A S E R e n a l S t o n e s......Page 2660
T e c h n i q u e......Page 2661
I n t e r p r e t a t i o n......Page 2662
P i t f a l l s......Page 2666
C A L C I F I E D R E N A L M A S S E S......Page 2669
C Y S T I C R E N A L D I S E A S E......Page 2672
P A R A P E L V I C C Y S T S......Page 2679
A u t o s o m a l D o m i n a n t P o l y c y s t i c K i d n e y D i......Page 2681
A c q u i r e d C y s t i c D i s e a s e o f t h e K i d n e y......Page 2685
T u b e r o u s S c l e r o s i s......Page 2688
V o n H i p p e l - L i n d a u D i s e a s e......Page 2689
O t h e r C y s t i c D i s e a s e s......Page 2692
R E N A L M A L I G N A N C Y......Page 2694
R e n a l C e l l C a r c i n o m a......Page 2695
S t a g i n g o f R e n a l C e l l C a r c i n o m a......Page 2698
T r e a t m e n t a n d F o l l o w - u p I m a g i n g......Page 2704
C y s t i c L e s i o n s a n d R a r e T u m o r T y p e s......Page 2705
T r a n s i t i o n a l C e l l C a r c i n o m a......Page 2707
L y m p h o m a......Page 2713
M e t a s t a s e s......Page 2716
R e n a l S a r c o m a......Page 2718
C o l l e c t i n g D u c t C a r c i n o m a......Page 2720
B E N I G N R E N A L L E S I O N S O n c o c y t o m a......Page 2722
A n g i o m y o l i p o m a......Page 2725
A c u t e I n f e c t i o n......Page 2729
R E N A L A B S C E S S......Page 2735
C H R O N I C R E N A L I N F E C T I O N S......Page 2739
U R I N A R Y O B S T R U C T I O N......Page 2743
R E N A L F A I L U R E......Page 2745
R E N A L T R A U M A......Page 2746
I m a g i n g M e t h o d s......Page 2747
C T T e c h n i q u e......Page 2748
C l a s s i f i c a t i o n o f R e n a l I n j u r i e s......Page 2749
G r a d e 1 I n j u r i e s......Page 2750
G r a d e s 2 a n d 3 I n j u r i e s......Page 2751
G r a d e 4 I n j u r i e s......Page 2753
G r a d e 5 I n j u r i e s......Page 2754
V a s c u l a r C o n t r a s t E x t r a v a s a t i o n......Page 2757
I m a g e R e v i e w......Page 2759
C T A f o r R e n a l A r t e r y S t e n o s i s , R e n a l A r......Page 2761
R e n a l A r t e r y A n e u r y s m......Page 2763
V a s c u l i t i s......Page 2765
R e n a l A r t e r y D i s s e c t i o n......Page 2767
N u t c r a c k e r S y n d r o m e......Page 2768
C o m p u t e d T o m o g r a p h y A n g i o g r a p h y f o r S u r......Page 2769
U P J O b s t r u c t i o n......Page 2770
C o m p u t e d T o m o g r a p h y a n d C o m p u t e d T o m o g r a......Page 2771
R e n a l B i o p s y......Page 2773
R e n a l T r a n s p l a n t P r e o p e r a t i v e E v a l u a t i o......Page 2778
R e n a l T r a n s p l a n t P r e o p e r a t i v e E v a l u a t i o......Page 2779
R e n a l T r a n s p l a n t P o s t o p e r a t i v e E v a l u a t i......Page 2780
T r a n s p l a n t P o s t o p e r a t i v e C h r o n i c C o m p l i......Page 2781
R a d i o f r e q u e n c y A b l a t i o n o f R e n a l M a s s......Page 2782
R e f e r e n c e s......Page 2786
1 9 - T h e A d r e n a l G l a n d s......Page 2829
T h e A d r e n a l G l a n d s......Page 2830
N O R M A L A N A T O M Y......Page 2834
P S E U D O T U M O R S......Page 2838
P A T H O L O G Y......Page 2840
C U S H I N G S Y N D R O M E......Page 2847
P R I M A R Y A L D O S T E R O N I S M......Page 2851
A D R E N A L C A R C I N O M A......Page 2855
P H E O C H R O M O C Y T O M A......Page 2862
N O N H Y P E R F U N C T I O N I N G N E O P L A S M S......Page 2870
N O N H Y P E R F U N C T I O N I N G A D E N O M A S......Page 2871
M E T A S T A T I C D I S E A S E......Page 2885
A D R E N A L L Y M P H O M A......Page 2894
M Y E L O L I P O M A......Page 2895
A D R E N A L C Y S T S......Page 2898
I N F L A M M A T O R Y D I S E A S E......Page 2902
A D R E N A L H E M O R R H A G E......Page 2908
A D D I S O N D I S E A S E......Page 2915
C O M P U T E D T O M O G R A P H Y A N D O T H E R I M A G I N G T E......Page 2919
A C K N O W L E D G M E N T......Page 2923
R E F E R E N C E S......Page 2925
2 0 - P e l v i s......Page 2939
C o m p u t e d T o m o g r a p h y......Page 2940
N O R M A L A N A T O M Y......Page 2942
C o m p u t e d T o m o g r a p h y F e m a l e P e l v i s......Page 2943
M a l e P e l v i s......Page 2944
M a g n e t i c R e s o n a n c e I m a g i n g F e m a l e P e l v i s......Page 2945
M a l e P e l v i s......Page 2947
B E N I G N A N D M A L I G N A N T D I S E A S E O F T H E F E M A......Page 2949
M Г ј l l e r i a n A n o m a l i e s......Page 2950
F i b r o i d s......Page 2953
A d e n o m y o s i s......Page 2955
P o l y c y s t i c O v a r i a n D i s e a s e......Page 2956
C o m p u t e d T o m o g r a p h y a n d M a g n e t i c R e s o n a......Page 2957
D e r m o i d......Page 2959
E n d o m e t r i o s i s......Page 2960
C y s t a d e n o m a......Page 2961
T u b o o v a r i a n A b s c e s s......Page 2962
O v a r i a n T o r s i o n......Page 2963
M a g n e t i c R e s o n a n c e I m a g i n g......Page 2964
E n d o m e t r i o s i s......Page 2965
T u b o o v a r i a n A b s c e s s......Page 2966
G y n e c o l o g i c N e o p l a s m s......Page 2967
T A B L E 2 0 - 1 S T A G I N G O F C E R V I C A L C A R C I N O M......Page 2969
F I G O S u r g i c a l S t a g e s......Page 2970
C o m p u t e d T o m o g r a p h y C e r v i c a l C a n c e r......Page 2971
T A B L E 2 0 - 3 S T A G I N G O F O V A R I A N C A R C I N O M A......Page 2972
F I G O S t a g e......Page 2973
E n d o m e t r i a l C a n c e r......Page 2974
O v a r i a n C a n c e r......Page 2978
M a g n e t i c R e s o n a n c e I m a g i n g C e r v i c a l C a n c......Page 2980
E n d o m e t r i a l C a n c e r......Page 2981
O v a r i a n C a n c e r......Page 2982
M a g n e t i c R e s o n a n c e I m a g i n g o f P e l v i c F l......Page 2983
P r e g n a n c y......Page 2985
C o m p u t e d T o m o g r a p h y......Page 2986
M a g n e t i c R e s o n a n c e I m a g i n g......Page 2987
F e t a l A n o m a l i e s......Page 2989
C o m p u t e d T o m o g r a p h y......Page 2990
M a g n e t i c R e s o n a n c e I m a g i n g......Page 2991
M a g n e t i c R e s o n a n c e I m a g i n g......Page 2996
P E L V I C N E O P L A S M S C O M M O N T O B O T H S E X E S B l......Page 2997
T A B L E 2 0 - 5 S T A G I N G O F U R I N A R Y B L A D D E R C......Page 2998
C o m p u t e d T o m o g r a p h y......Page 3000
M a g n e t i c R e s o n a n c e I m a g i n g......Page 3001
R e c u r r e n t C o l o r e c t a l C a n c e r F o l l o w i n g A b......Page 3002
C o m p u t e d T o m o g r a p h y......Page 3003
P E L V I S......Page 3006
R E F E R E N C E S......Page 3008
2 1 - C o m p u t e d T o m o g r a p h y o f T h o r a c o a b d o m......Page 3017
J o s e p h K . T . L e e......Page 3018
B L U N T T H O R A C I C T R A U M A......Page 3019
I N D I C A T I O N S......Page 3020
S P E C I F I C T R A U M A S I T E S C h e s t W a l l......Page 3022
P n e u m o t h o r a x......Page 3027
P l e u r a l E f f u s i o n / H e m o t h o r a x......Page 3029
P u l m o n a r y C o n t u s i o n......Page 3032
P u l m o n a r y L a c e r a t i o n , P n e u m a t o c e l e , a n d......Page 3035
A o r t a a n d G r e a t V e s s e l s......Page 3037
H e a r t a n d P e r i c a r d i u m......Page 3049
T r a c h e a a n d B r o n c h i......Page 3053
E s o p h a g u s......Page 3054
D i a p h r a g m......Page 3056
B L U N T A B D O M I N A L T R A U M A......Page 3062
I N D I C A T I O N S......Page 3063
T E C H N I Q U E......Page 3065
H E M O P E R I T O N E U M......Page 3067
S P E C I F I C T R A U M A S I T E S S p l e e n......Page 3073
D e s c r i p t i o n o f i n j u r y......Page 3082
L i v e r......Page 3084
T A B L E 2 1 - 3 C O M P U T E D T O M O G R A P H Y - B A S E D I......Page 3093
P a n c r e a s......Page 3094
B o w e l a n d M e s e n t e r y......Page 3100
K i d n e y......Page 3108
U r e t e r......Page 3117
B l a d d e r......Page 3118
R E F E R E N C E S......Page 3123
2 2 - M u s c u l o s k e l e t a l S y s t e m......Page 3159
M u s c u l o s k e l e t a l S y s t e m......Page 3160
U P P E R E X T R E M I T Y : S H O U L D E R A N D A R M , I N C L U......Page 3173
T r a u m a......Page 3180
J o i n t A b n o r m a l i t y......Page 3195
U P P E R E X T R E M I T Y : E L B O W A n a t o m y......Page 3207
T r a u m a......Page 3209
J o i n t A b n o r m a l i t y......Page 3218
U P P E R E X T R E M I T Y : W R I S T A N D H A N D A n a t o m y......Page 3224
T r a u m a......Page 3226
P E L V I S , A C E T A B U L U M , A N D H I P S A n a t o m y......Page 3238
T r a u m a......Page 3240
J o i n t A b n o r m a l i t y......Page 3262
A n a t o m y......Page 3275
T r a u m a......Page 3279
I n t e r n a l J o i n t D e r a n g e m e n t s......Page 3287
O t h e r C o n d i t i o n s A s s e s s e d W i t h C T P a t e l l......Page 3298
T o t a l K n e e A r t h r o p l a s t y......Page 3299
C o n g e n i t a l V a r i a n t s......Page 3305
T r a u m a......Page 3310
S t r e s s F r a c t u r e s......Page 3332
I n t e r n a l J o i n t D e r a n g e m e n t s a n d A r t h r i t......Page 3333
A r t h r i t i s......Page 3336
B o n e......Page 3339
S o f t T i s s u e s......Page 3353
O s t e o m y e l i t i s......Page 3369
S e p t i c A r t h r i t i s......Page 3372
C e l l u l i t i s , M y o s i t i s , F a s c i t i s , A b s c e s s......Page 3373
A t y p i c a l I n f e c t i o n s......Page 3375
I d i o p a t h i c I n f l a m m a t o r y M y o p a t h y......Page 3376
M E T A B O L I C......Page 3377
F r a g i l i t y F r a c t u r e s......Page 3381
B i o p s i e s......Page 3382
I m a g e - G u i d e d A b l a t i o n o f O s s e o u s L e s i o n......Page 3390
O t h e r L e s i o n s......Page 3392
C T - G u i d e d A s p i r a t i o n s a n d T h e r a p e u t i c I n......Page 3394
I m a g e - G u i d e d P l a c e m e n t o f O r t h o p e d i c H a r......Page 3397
R E F E R E N C E S......Page 3400
2 3 - T h e S p i n e......Page 3425
C e r v i c a l S p i n e......Page 3426
T h o r a c i c S p i n e......Page 3428
S a c r u m a n d C o c c y x......Page 3430
S p e c i a l I m a g i n g F e a t u r e s......Page 3431
I M A G I N G P R O T O C O L S C e r v i c a l S p i n e C o m p u t e......Page 3436
M a g n e t i c R e s o n a n c e I m a g i n g......Page 3437
A D V A N T A G E S A N D D I S A D V A N T A G E S O F C O M P U T E D......Page 3439
S P I N A L T R A U M A......Page 3440
C 2 ( A x i s )......Page 3441
H y p e r e x t e n s i o n I n j u r i e s......Page 3442
H y p e r f l e x i o n I n j u r i e s......Page 3446
T h o r a c i c S p i n e......Page 3452
T h o r a c o l u m b a r a n d L u m b a r S p i n e......Page 3453
S a c r u m......Page 3456
P a t h o l o g i c F r a c t u r e s a n d S e c o n d a r y T u m o......Page 3457
D E G E N E R A T I V E S P I N E D I S E A S E......Page 3461
D i s c H e r n i a t i o n......Page 3474
S p o n d y l o s i s a n d O s t e o c h o n d r o s i s......Page 3481
F a c e t J o i n t D i s e a s e......Page 3483
S p i n a l S t e n o s i s......Page 3486
S p o n d y l o l i s t h e s i s a n d S p o n d y l o l y s i s......Page 3491
P O S T O P E R A T I V E S P I N E......Page 3493
I N F E C T I O N S O F T H E S P I N E......Page 3498
R h e u m a t o i d A r t h r i t i s......Page 3504
A n k y l o s i n g S p o n d y l o a r t h r i t i s......Page 3508
H e m a n g i o m a......Page 3509
A n e u r y s m a l B o n e C y s t......Page 3510
O s t e o b l a s t o m a......Page 3513
G i a n t C e l l T u m o r......Page 3514
C h o r d o m a......Page 3515
L a n g e r h a n s C e l l H i s t i o c y t o s i s......Page 3516
S E L E C T E D S P I N A L V A S C U L A R D I S O R D E R S V a s c u......Page 3518
E p i d u r a l H e m a t o m a......Page 3519
F U T U R E T R E N D S I N S P I N E M R I......Page 3522
R E F E R E N C E S......Page 3526
2 4 - P e d i a t r i c A p p l i c a t i o n s......Page 3535
S e d a t i o n......Page 3536
C o m p u t e d T o m o g r a p h y : S p e c i a l C o n s i d e r a t......Page 3537
B o w e l O p a c i f i c a t i o n......Page 3538
C T T e c h n i c a l C o n s i d e r a t i o n s S c a n D e l a y T......Page 3539
T e c h n i c a l P a r a m e t e r s......Page 3540
P u l s e S e q u e n c e s......Page 3541
O t h e r M a g n e t i c R e s o n a n c e I m a g i n g T e c h n i......Page 3542
O p t i m i z i n g I m a g e Q u a l i t y......Page 3543
T h y m u s......Page 3544
A z y g o e s o p h a g e a l R e c e s s......Page 3547
L y m p h o m a......Page 3549
T h y m i c H y p e r p l a s i a......Page 3551
T h y m o m a......Page 3553
M i s c e l l a n e o u s L e s i o n s......Page 3554
A n t e r i o r M e d i a s t i n a l M a s s e s : F a t A t t e n u......Page 3555
T h y m o l i p o m a......Page 3557
C y s t i c H y g r o m a......Page 3558
L y m p h a d e n o p a t h y......Page 3559
F o r e g u t C y s t s......Page 3560
P o s t e r i o r M e d i a s t i n a l M a s s e s......Page 3561
A o r t i c A r c h......Page 3563
S u p e r i o r V e n a C a v a......Page 3565
C o n g e n i t a l A n o m a l i e s......Page 3567
A n o m a l i e s W i t h N o r m a l V a s c u l a t u r e......Page 3568
A n o m a l i e s W i t h A b n o r m a l V a s c u l a t u r e......Page 3569
P u l m o n a r y M e t a s t a s e s......Page 3572
D i f f u s e P a r e n c h y m a l D i s e a s e......Page 3574
P u l m o n a r y I n f e c t i o n s......Page 3576
P a r e n c h y m a l o r P l e u r a l D i s e a s e......Page 3578
A i r w a y D i s e a s e......Page 3579
P u l m o n a r y A r t e r i e s a n d V e i n s......Page 3581
C a r d i a c D i s e a s e......Page 3583
A B D O M E N......Page 3584
S o l i d R e n a l T u m o r s W i l m s T u m o r......Page 3585
N e p h r o b l a s t o m a t o s i s......Page 3588
L y m p h o m a......Page 3589
R a r e R e n a l T u m o r s......Page 3590
C y s t i c R e n a l M a s s e s......Page 3592
C y s t i c D i s e a s e......Page 3593
A n g i o m y o l i p o m a......Page 3594
H e m o r r h a g e......Page 3595
N e u r o b l a s t o m a......Page 3596
A d r e n o c o r t i c a l N e o p l a s m s......Page 3597
P h e o c h r o m o c y t o m a......Page 3598
R e t r o p e r i t o n e a l S o f t T i s s u e M a s s e s......Page 3600
P r i m a r y M a l i g n a n t N e o p l a s m s......Page 3601
H e p a t i c M e t a s t a s e s......Page 3606
B e n i g n N e o p l a s m s......Page 3607
B i l i a r y M a s s e s......Page 3609
P a n c r e a t i c M a s s e s......Page 3610
S p l e n i c M a s s e s......Page 3611
G a s t r o i n t e s t i n a l a n d M e s e n t e r i c M a s s e s......Page 3613
L y m p h o m a......Page 3614
B l u n t A b d o m i n a l T r a u m a......Page 3615
D i f f u s e L i v e r D i s e a s e s......Page 3619
R e n a l P a r e n c h y m a l D i s e a s e......Page 3621
R e n a l V a s c u l a r D i s e a s e s......Page 3623
H e r e d i t a r y D i s e a s e s......Page 3624
B o w e l D i s e a s e s......Page 3626
C o n g e n i t a l A n o m a l i e s......Page 3627
I n f l a m m a t i o n......Page 3628
O b s t r u c t i o n......Page 3630
O v a r i a n M a s s e s......Page 3631
V a g i n a l / U t e r i n e M a s s e s......Page 3633
P r e s a c r a l M a s s e s......Page 3635
U n i c o r n u a t e U t e r u s......Page 3640
I m p a l p a b l e T e s t e s......Page 3641
M U S C U L O S K E L E T A L S Y S T E M......Page 3642
B o n e M a r r o w......Page 3643
O s s e o u s N e o p l a s m s......Page 3644
S o f t T i s s u e N e o p l a s m s......Page 3646
B o n e a n d J o i n t T r a u m a......Page 3652
J o i n t D i s o r d e r s......Page 3653
C o n g e n i t a l A n o m a l i e s......Page 3654
R E F E R E N C E S......Page 3656
C o n t r a s t i n j e c t i o n r a t e......Page 3676
M i s c e l l a n e o u s......Page 3677
C o m m e n t s......Page 3678
M i s c e l l a n e o u s......Page 3679
M i s c e l l a n e o u s......Page 3680

Citation preview

Cover 1

6

Cover

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

8

Editors & Authors 2

Editors & Authors Editors: Le e , Jose ph K. T. ; Sa ge l, Stua rt S. ; Sta nle y , Robe rt J. ; He ike n, Ja y P. Title : C ompute d Body Tomogra phy with MRI C orre la tion , 4th Edition Copy right В©2006 Lippinc ot t Williams & Wilkins > F ront of Book > Edit ors

Editors Jose ph K. T. Le e MD E. H. Wood Dist inguished Prof essor and Chair Depar t m ent of Radiology , Univ er sit y of Nor t h Car olina Sc hool of Medic ine, Chapel Hill, Nor t h Car olina Stua rt S. Sa ge l MD Prof essor of Radiology Dir ec t or , Chest Radiology Sec t ion, Mallinc kr odt Inst it ut e of Radiology , Washingt on Univ er sit y Sc hool of Medic ine, St . Louis, Missour i Robe rt J. Sta nle y MD, MSHA Edit or- in- Chief , Americ an Journal of Roent genology Pr of essor and Chair Em er it us, Depar t m ent of Radiology , Univ er sit y of Alabam a at Bir m ingham , Bir m ingham , Alabam a Ja y P. He ike n MD Prof essor of Radiology Dir ec t or , Abdom inal Im aging Sec t ion, Mallinc kr odt Inst it ut e of Radiology , Washingt on Univ er sit y Sc hool of Medic ine, St . Louis, Missour i

Secondary Editors Lisa Mc Alliste r Ac quisit ions Edit or Ke rry Ba rre tt Managing Edit or F ra n Gunning Projec t Manager Be n Riv e ra

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3

Table of Contents 1.

Cover

5

2.

Editors & Authors

7

3.

Dedication

15

4.

Preface

17

5.

Acknowledgments

21

6.

1 - Basic Principles of Computed Tomography Physics and Technical Considerations

23

7.

2 - Magnetic Resonance Imaging Principles and Applications

85

8.

3 - Interventional Computed Tomography

241

9.

4 - Neck

361

10. 5 - Thorax: Techniques and Normal Anatomy

553

11. 6 - Mediastinum

713

12. 7 - Lung

945

13. 8 - Pleura, Chest Wall, and Diaphragm

1239

14. 9 - Heart and Pericardium

1449

15. 10 - Normal Abdominal and Pelvic Anatomy

1539

16. 11 - Gastrointestinal Tract

1655

17. 12 - Liver

1779

18. 13 - The Biliary Tract

2009

19. 14 - Spleen

2109

20. 15 - The Pancreas

2191

21. 16 - Abdominal Wall and Peritoneal Cavity

2377

22. 17 - Retroperitoneum

2499

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

4

Table of Contents 23. 18 - The Kidney and Ureter

2657

24. 19 - The Adrenal Glands

2847

25. 20 - Pelvis

2957

26. 21 - Computed Tomography of Thoracoabdominal Trauma

3035

27. 22 - Musculoskeletal System

3177

28. 23 - The Spine

3443

29. 24 - Pediatric Applications

3553

Index

Computed Body Tomography with MRI Correlation , 4th Edition

0

© 2017 Enter your company name

1 - Basic Principles of Computed Tomography Physics and Technical Considerations

24 1 - Basic Principles of Computed Tomography Physics and Technica 6

1 - Basic Principles of Computed Tomography Physics and Technical Considerations Editors: Le e , Jose ph K. T. ; Sa ge l, Stua rt S. ; Sta nle y , Robe rt J. ; He ike n, Ja y P. Title : C ompute d Body Tomogra phy with MRI C orre la tion , 4th Edition Copy right В©2006 Lippinc ot t Williams & Wilkins > T able of Cont ent s > 1 - Basic Princ iples of Comput ed T omography Phy sic s and T ec hnic al Considerat ions

1 Basic Principles of Computed Tomography Physics and Technical Considerations Ky ongta e T. Ba e Bruc e R. Whiting

INTRODUCTION Slight ly more t han t hree dec ades old, c omput ed t omography (CT ) c ont inues t o adv anc e rapidly in bot h imaging perf ormanc e and w idening c linic al applic at ions. An apprec iat ion of t he pot ent ial of CT and it s limit at ions c an be obt ained w it h an underst anding of basic princ iples of CT operat ions. T his c hapt er prov ides bac kground and insight int o t he t ec hnic al issues surrounding t he applic at ion of CT , inc luding t he image f ormat ion proc ess, v arious paramet ers af f ec t ing c linic al usage, met ric s t o desc ribe perf ormanc e, t he display of image inf ormat ion, and radiat ion dose.

Imaging with X-Rays X- ray imaging w as t he f irst diagnost ic imaging t ec hnology , inv ent ed immediat ely af t er t he disc ov ery of x- ray s by Roent gen in 1895. X- ray s are a f orm of elec t romagnet ic energy t hat propagat e t hrough spac e and are absorbed or sc at t ered by int erac t ions w it h at oms. T he at t enuat ion of beam energy on passage t hrough phy sic al objec t s prov ides a noninv asiv e means t o gat her inf ormat ion about t he amount and t y pe of mat erial present inside t he objec t . In radiography , x- ray s illuminat e an objec t , result ing in a t w odimensional (2D) image t hat is t he “ shadow ” of t hree- dimensional (3D) st ruc t ures present in t he beam. T he projec t ion c auses a superposit ion of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

25 1 - Basic Principles of Computed Tomography Physics and Technica int ernal st ruc t ures, leading t o indet erminac y in t he exac t relat ionships, shapes, and relat iv e posit ions of objec t s. Bec ause of t his indet erminac y , radiologist s require ext ensiv e t raining and experienc e t o int erpret 3D st ruc t ures f rom t he 2D image dat a. F urt hermore, projec t ion radiographs hav e v ery limit ed abilit y t o dif f erent iat e low - c ont rast dif f erenc es in t issues. Comput ed t omography (CT ) w as c reat ed in t he early 1970s t o ov erc ome many of t hese limit at ions (13). By ac quiring mult iple x- ray v iew s of an objec t and perf orming mat hemat ic al operat ions on digit al dat a, a f ull 2D sec t ion of t he objec t c an be rec onst ruc t ed w it h exquisit e det ail of t he anat omy present (F ig. 1- 1). During t he y ears sinc e it s inv ent ion, CT t ec hnology has undergone c ont inual improv ement in perf ormanc e t hrough ref inement s in c omponent s and innov at ion in sc anning t ec hniques (19). As a result , sc an t imes hav e dramat ic ally improv ed, and v olume c ov erage and resolut ion det ail hav e inc reased. P.2 As a c urious c onsequenc e of t his progress, t he v ery large v olume of image dat a ac quired w it h c urrent sc anning t ec hniques poses anot her c hallenge f or int erpret at ion: how t o display v ery large amount s of inf ormat ion f or t he int erpret at ion proc ess. T he magnit ude and c omplexit y of t rue v olume imaging requires new rendering t ec hniques t o enable produc t iv e exploit at ion of t he v ast amount of inf ormat ion.

F igure 1- 1 A: X- ray and B: Comput ed t omography of head w it h c oc hlear implant . Not e t he higher c ont rast of f ine st ruc t ures in t he c omput ed t omography slic e, w hereas superposit ion of st ruc t ures in t he x- ray c onf ounds t he t hree dimensional loc at ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

26 1 - Basic Principles of Computed Tomography Physics and Technica Brief History of Computed Tomography Sinc e it s int roduc t ion in t he mid- 1970s, CT sc anner t ec hnology has undergone a c ont inual improv ement in perf ormanc e, inc luding inc reases in ac quisit ion speed, amount of inf ormat ion in indiv idual slic es, and v olume of c ov erage. A graph (F ig. 1- 2) of t hese paramet ers v ersus t ime looks similar t o Moore's Law f or c omput er pric e- perf ormanc e, w hic h observ es t hat c omput er met ric s (c loc k speed, c ost of random ac c ess memory or magnet ic st orage, et c .) double ev ery 18 mont hs. In t he c ase of CT t ec hnology , t he doubling period is approximat ely 32 mont hs, st ill an impressiv e rat e. F or example, sc an t ime per slic e has dec reased f rom 300 sec onds in 1972 t o 0.005 sec onds in 2005. F ac t ors c ont ribut ing t o t his remarkable adv anc e inc lude improv ement s in elec t ronic s hardw are and dev elopment of innov at iv e mec hanic al sc anning c onf igurat ions. Hist oric ally , t he early sc anner c onf igurat ions w ere c harac t erized as suc c essiv e generat ions of sc anner geomet ry (F ig. 1- 3). By 1990 rot at ing f an beam sy st ems, ut ilizing slip- ring t ec hnology t o allow c ont inuous rot at ion of x- ray t ube and det ec t or, had reduc ed ac quisit ion t ime t o about 1 sec ond, w it h rec onst ruc t ion c omput at ions requiring sev eral sec onds per slic e. Nev ert heless, t he t ime required t o sc an a pat ient v olume of int erest of t en w as longer t han a single breat h- hold, and sc an range w as limit ed by x- ray t ube heat load t o 10 t o 30 c m. By t ranslat ing t he pat ient t able c ont inuously t hrough t he rot at ing gant ry , t ermed helic al or spir al sc anning, v olume c ov erage and sc an speed w ere f urt her inc reased, w it h f undament al rat e limit at ions being x- ray P.3 t ube out put and mec hanic al rot at ion rat e. Image rec onst ruc t ion t ec hniques w ere dev eloped t o int erpolat e 2D planes f rom t he 3D dat aset s t hat w ere ac quired in helic al mode. In t he lat e 1990s, t he obst ac les enc ount ered by early helic al sc anners w ere ov erc ome by mult idet ec t or row t ec hnology , using mult iple set s of det ec t or row s t o ut ilize more of t he x- ray t ube out put and ac quire measurement s at mult iple sec t ion lev els in parallel. Rec onst ruc t ion under t hese c ondit ions is inherent ly 3D, so more c omplex algorit hms must be used. Benef it ing f rom subst ant ial improv ement s in c omput ing pow er, t he rapid inc reases in CT perf ormanc e appear t o be sust ainable int o t he new c ent ury , w it h dev elopment of f lat panel det ec t ors, f ast er elec t ronic s, and c one- beam geomet ry rec onst ruc t ion algorit hms.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

27 1 - Basic Principles of Computed Tomography Physics and Technica

F igure 1- 2 Ev olut ion of c omput ed t omography sc anner perf ormanc e: plot of ac quisit ion perf ormanc e v ersus t ime, f or c omput ed t omography sc anners. T he slope implies a doubling of perf ormanc e approximat ely ev ery 2 y ears. (Dat a f rom Siemens Medic al Sy st ems, ht t p://w w w .medic al.siemens.c om, “ CT Hist ory and T ec hnology .” ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

28 1 - Basic Principles of Computed Tomography Physics and Technica

F igure 1- 3 Def init ion of t he dif f erent generat ions of sc an geomet ries.

T o underst and best how t o ut ilize CT t ec hnology c linic ally and apprec iat e new produc t c apabilit ies, know ledge of f undament al CT imaging princ iples is nec essary . T he basic princ iples of CT inv olv e phy sic al mec hanisms t hat are shared w it h x- ray imaging, plus mat hemat ic al t ec hniques t hat exc eed t he human v isual perc ept ion of 2D images. A c ommon t ec hnic al desc ript ion c an be used t o desc ribe bot h t he image f ormat ion proc ess and t he image v isualizat ion t ask. T hese w ill now be examined in det ail.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

29 1 - Basic Principles of Computed Tomography Physics and Technica COMPUTED TOMOGRAPHY ACQUISITION SYSTEM COMPONENTS Generation of X-Rays F or medic al imaging, x- ray s are generat ed by an x- ray t ube. In t his dev ic e, a met al f ilament is heat ed (muc h like a light bulb) unt il energet ic elec t rons esc ape f rom t he c at hode P.4 surf ac e int o a v ac uum. T hese elec t rons are t hen ac c elerat ed by an elec t ric f ield, ac quiring kinet ic energy w hile being at t rac t ed t o a posit iv e anode t arget . T he t ot al amount of energy ac quired by t he elec t ron in t he ac c elerat ing elec t ric f ield is equal t o t he produc t of t he pot ent ial (peak kilov olt age, kVp) t imes t he unit of elec t ric al c harge, possessing unit s of elec t ron v olt s (kilo elec t ron v olt s, keV). T he amount of c harge generat ed by t he x- ray t ube per unit t ime has unit s of elec t ric al c urrent (milliamperes, mA), and t he produc t of v olt age and c urrent is t he amount of pow er (w at t s) deliv ered by t he t ube. Elec t rost at ic and/or magnet ic f ields are used t o f oc us t he elec t ron beam int o a small area of t he anode t arget . T y pic ally , t his f oc al spot has dimensions of about 1 mm. When t he elec t rons c ollide w it h t he t arget , most of t heir energy is dissipat ed int o heat but a small f rac t ion ( T able of Cont ent s > 2 - Magnet ic Resonanc e Imaging Princ iples and Applic at ions

2 Magnetic Resonance Imaging Principles and Applications Ma rk A. Brown Ric ha rd C . Se me lka

PRODUCTION OF NET MAGNETIZATION Magnet ic resonanc e (MR) is based on t he int erac t ion bet w een an applied magnet ic f ield and a nuc leus t hat possesses spin. Nuc lear spin is one of sev eral int rinsic propert ies of an at om, and it s v alue depends on t he part ic ular at omic c omposit ion. Most element s in t he periodic t able hav e at least one nat urally oc c urring isot ope t hat possesses spin. T hus, in princ iple, nearly ev ery element c an be examined using MR, and t he basic ideas of resonanc e absorpt ion and relaxat ion are c ommon f or all t hese element s. T he prec ise det ails v ary f rom nuc leus t o nuc leus and f rom sy st em t o sy st em. At oms c onsist of t hree f undament al part ic les: prot ons, w hic h possess a posit iv e c harge; neut rons, w hic h hav e no c harge; and elec t rons, w hic h hav e a negat iv e c harge. T he prot ons and neut rons are loc at ed in t he nuc leus or c ore of an at om, w hereas t he elec t rons are loc at ed in shells, or orbit als, surrounding t he nuc leus. T he c harac t erist ic c hemic al reac t ions of element s depend on t he part ic ular number of eac h of t hese part ic les. T w o propert ies c ommonly used t o c at egorize element s are t he at omic number and t he at omic w eight . T he at omic number is t he number of prot ons in t he nuc leus and is t he primary index used t o dif f erent iat e at oms. All at oms of an element hav e t he same at omic number. T he at omic w eight is t he sum of t he number of prot ons and t he number of neut rons. At oms w it h t he same at omic number but dif f erent at omic w eight s are c alled isot opes.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 87 A t hird propert y of t he nuc leus is spin, or int rinsic spin angular moment um. T he nuc leus c an be c onsidered t o be c ont inuously rot at ing about an axis at a c onst ant rat e or v eloc it y . T his self - rot at ion axis is perpendic ular t o t he direc t ion of rot at ion (F ig. 2- 1). A limit ed number of v alues f or t he spin are f ound in nat ure; t hat is, t he spin, I, is quant ized t o c ert ain disc ret e v alues. T hese v alues depend on t he at omic number and at omic w eight of t he part ic ular nuc leus. T here are t w o groups of v alues f or I: int egral and half int egral v alues. A nuc leus has an int egral v alue f or I (e.g., 0, 1, 2, 3) if it has an ev en at omic w eight . If t he at omic number is ev en, t hen I = 0. Suc h a nuc leus does not int erac t w it h an ext ernal magnet ic f ield and c annot be st udied using MR. If t he at omic number is odd, t hen I is nonzero. A nuc leus has a half - int egral v alue f or I (e.g., 1/2, 3/2, 5/2) if it has an odd at omic w eight . T able 2- 1 list s t he spin and isot opic c omposit ions of some element s c ommonly f ound in biologic sy st ems. T he 1H nuc leus, c onsist ing of a single prot on, is a nat ural c hoic e f or probing t he body using MR t ec hniques f or sev eral reasons. It has a spin of 1/2 and is t he most abundant isot ope of hy drogen. It s response t o an applied magnet ic f ield is one of t he largest f ound in nat ure. F inally , t he body is c omposed of t issues t hat c ont ain primarily w at er and f at , bot h of w hic h c ont ain hy drogen.

F igure 2- 1 A rot at ing nuc leus w it h a posit iv e c harge produc es a magnet ic f ield know n as t he magnet ic moment , B, orient ed parallel t o t he axis of rot at ion (lef t ). T his arrangement is analogous t o a bar magnet in w hic h t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 88 magnet ic f ield is c onsidered t o be orient ed f rom t he sout h t o t he nort h pole (r ight ).

P.30 While a rigorous mat hemat ic al desc ript ion of a nuc leus w it h spin and it s int erac t ions requires t he use of quant um mec hanic al princ iples, most of MR c an be desc ribed using t he c onc ept s of c lassic al mec hanic s, part ic ularly in desc ribing t he ac t ions of a nuc leus w it h spin. T he subsequent disc ussions of MR phenomena in t his book use a c lassic al approac h. In addit ion, w hile t he c onc ept s of resonanc e absorpt ion and relaxat ion apply t o all nuc lei w it h spin, t he desc ript ions in t his c hapt er f oc us on 1H (c ommonly ref erred t o as a prot on) sinc e most imaging experiment s v isualize t he 1H nuc leus. Conc urrent w it h t he spinning, posit iv ely c harged nuc leus (t he loc at ion of t he prot ons) is a loc al magnet ic f ield know n as a m agnet ic m om ent . A bar magnet prov ides a usef ul analogy . A bar magnet has a nort h and a sout h pole or, more prec isely , a magnit ude and orient at ion, or direc t ion, t o t he magnet ic f ield c an be def ined. A nuc leus w it h spin has an axis of rot at ion t hat c an be v iew ed as a v ec t or w it h a def init e orient at ion and magnit ude (see F ig. 2- 1). T he magnet ic moment f or t he nuc leus is parallel t o t he axis of rot at ion. T his orient at ion of t he nuc lear spin and t he c hanges induc ed in it due t o t he experiment al manipulat ions t hat t he nuc leus undergoes prov ide t he basis f or t he MR signal. In general, MR measurement s are made on c ollec t ions of similar spins rat her t han on an indiv idual spin. It is usef ul t o c onsider suc h a c ollec t ion bot h as indiv idual spins ac t ing independent ly (a “ mic rosc opic ” pic t ure) and as a single ent it y (a “ mac rosc opic ” pic t ure). F or many c onc ept s, t he t w o pic t ures prov ide equiv alent result s, ev en t hough t he mic rosc opic pic t ure is more c omplet e. F or most c onc ept s present ed in t his c hapt er, t he mac rosc opic pic t ure is suf f ic ient f or an adequat e desc ript ion. When nec essary , t he mic rosc opic pic t ure is used. Consider an arbit rary v olume of t issue c ont aining hy drogen at oms (prot ons). Eac h prot on has a spin v ec t or of equal magnit ude. How ev er, t he spin v ec t ors f or t he ent ire c ollec t ion of prot ons w it hin t he t issue are randomly orient ed in all direc t ions. Perf orming a v ec t or addit ion of t hese spin v ec t ors produc es a zero sum; t hat is, no net magnet izat ion is observ ed in t he t issue (F ig. 2- 2). If t he t issue is plac ed inside a magnet ic f ield B, 1 t he indiv idual prot ons begin t o rot at e perpendic ular t o, or prec ess about , t he magnet ic f ield. T he prot ons are t ilt ed slight ly aw ay f rom t he axis of t he magnet ic f ield, but t he axis of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 89 rot at ion is parallel t o B 0. T his prec ession is at a c onst ant rat e and oc c urs bec ause of t he int erac t ion of t he magnet ic f ield w it h t he spinning posit iv e c harge of t he nuc leus. By c onv ent ion, B 0 and t he axis of prec ession are def ined t o be orient ed in t he z direc t ion of a Cart esian c oordinat e sy st em. T he mot ion of eac h prot on c an be desc ribed by a unique set of c oordinat es perpendic ular (x and y ) and parallel (z) t o B 0. T he perpendic ular, or t ransv erse, c oordinat es are nonzero and v ary w it h t ime as t he prot on prec esses, but t he z c oordinat e is c onst ant w it h t ime (F ig. 2- 3). T he rat e, or f requenc y , of prec ession is proport ional t o t he st rengt h of t he magnet ic f ield and is expressed by Eq. 1, t he Larmor equat ion: w here П‰ 0 is t he Larmor f requenc y in megahert z (MHz), 2 B0 is t he magnet ic f ield st rengt h in T esla (T ) t hat t he prot on experienc es, and Оіg is a c onst ant f or eac h nuc leus in s -1T -1, know n as t he gy romagnet ic rat io. Values f or П‰ 0 and Оі at 1.5 T f or sev eral nuc lei are t abulat ed in T able 2- 1. If a v ec t or addit ion is perf ormed, as bef ore, f or t he spin v ec t ors inside t he magnet ic f ield, t he result s w ill be slight ly dif f erent f rom t hose f or t he sum out side t he f ield. In t he direc t ion perpendic ular t o B 0, t he spin orient at ions are st ill randomly dist ribut ed just as t hey w ere out side t he magnet ic f ield, in spit e of t he t ime- v ary ing nat ure of eac h t ransv erse c omponent . T here is st ill no net magnet izat ion perpendic ular t o B 0. How ev er, in t he direc t ion parallel t o t he magnet ic f ield, t here is a dif f erent result . Bec ause t here is an orient at ion t o t he prec essional axis of t he prot on t hat is c onst ant w it h t ime, t here is a c onst ant , nonzero int erac t ion, or c oupling, bet w een t he prot on and B 0. T his c oupling c auses a dif f erenc e in energy bet w een P.31 prot ons aligned parallel t o or along B 0 and t hose aligned ant iparallel t o or against B 0. T his energy dif f erenc e, ОґE, is proport ional t o B 0 (F ig. 2- 4). T he orient at ion t hat is parallel t o B 0 (also know n as spin up) is of low er energy t han t he ant iparallel orient at ion (also know n as spin dow n). F or a c ollec t ion of prot ons, more w ill be orient ed parallel t o B 0 t han ant iparallel t o B 0; t hat is, t here is an induc ed polarizat ion of t he spin orient at ion by t he magnet ic f ield (F ig. 2- 5A). T he dist ribut ion of prot ons in eac h energy lev el may be c alc ulat ed using t he Bolt zmann dist ribut ion f unc t ion. T he exac t number of prot ons in

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 90 eac h lev el depends on B 0 (t hrough ОґE) and inc reases w it h inc reasing B 0. F or a c ollec t ion of prot ons at body t emperat ure (310 K) at 1.5 T , t here w ill t y pic ally be an exc ess of ~ 1:10 6 prot ons in t he low er lev el out of t he approximat ely 10 25 prot ons w it hin t he t issue v olume. T his unequal number of prot ons in eac h energy lev el means t hat t he v ec t or sum of spins w ill be nonzero and w ill point parallel t o t he magnet ic f ield. In ot her w ords, t he t issue w ill bec ome polarized or magnet ized in t he presenc e of B 0 w it h a v alue M 0, know n as t he net magnet izat ion. T he orient at ion of t his P.32 net magnet izat ion w ill be in t he same direc t ion as B 0 and w ill be c onst ant w it h respec t t o t ime (F ig. 2- 5B). F or t issues in t he body , t he magnit ude of M 0 is proport ional t o B 0 (equat ion 2): w here Оє is know n as t he bulk magnet ic susc ept ibilit y or simply t he magnet ic susc ept ibilit y . T his arrangement , w it h M 0aligned along t he magnet ic f ield w it h no t ransv erse c omponent , is t he normal, or equilibrium, c onf igurat ion f or t he prot ons. T his c onf igurat ion of spins has t he low est energy and is t he arrangement t o w hic h t he prot ons w ill nat urally t ry t o ret urn f ollow ing any pert urbat ions, suc h as energy absorpt ion. T his induc ed magnet izat ion, M 0, is t he sourc e of signal f or all MR experiment s. Consequent ly , all ot her t hings being equal, t he great er t he f ield st rengt h, t he great er t he v alue of M 0 and t he great er t he pot ent ial MR signal.

F igure 2- 2 Mic rosc opic and mac rosc opic pic t ures of a c ollec t ion of prot ons in t he absenc e of an ext ernal magnet ic f ield. In t he absenc e of a f ield, t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 91 prot ons hav e t heir spin v ec t ors orient ed randomly (mic rosc opic pic t ure, lef t ). T he v ec t or sum of t hese spin v ec t ors is zero (mac rosc opic pic t ure, r ight ).

F igure 2- 3 Inside a magnet ic f ield, a prot on prec esses or rev olv es about t he magnet ic f ield. T he prec essional axis is parallel t o t he main magnet ic f ield, B 0. T he z c omponent of t he spin v ec t or (projec t ion of t he spin ont o t he z axis) is t he c omponent of int erest bec ause it does not c hange in magnit ude or direc t ion as t he prot on prec esses. T he x and y c omponent s v ary w it h t ime at a f requenc y П‰ 0 proport ional t o B 0 as expressed by Eq. 1.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 92 F igure 2- 4 Zeeman diagram. In t he absenc e of a magnet ic f ield (lef t ), a c ollec t ion of prot ons w ill be equal in energy so t hat t here is no pref erent ial alignment . In t he presenc e of a magnet ic f ield (r ight ), t he spin up orient at ion (z c omponent parallel t o t he magnet ic f ield, B 0) is of low er energy and it s c onf igurat ion c ont ains more prot ons t han t he higher energy , spin dow n c onf igurat ion. T he dif f erenc e in energy , ОґE, bet w een t he t w o lev els is proport ional t o B 0. TABLE 2- 1 SELEC TED ELEMENTS OF THE PERIODIC TABLE Nuc le a r c omposition Ele me nt 1H,

Protons 1

Ne utrons 0

Nuc le a r Spin, I 1/2

Gy roma gn e tic ra tio % Na tura l Оі(MHz T- a bunda nc 1) e 42.5774 99.985

П‰ a t 1. 5 T (MHz) 63.8646

Prot ium 2H, 1 1 1 6.53896 0.015 9.8036 Deut erium 3He 2 1 1/2 32.436 0.000138 48.6540 6Li 3 3 1 6.26613 7.5 9.39919 7Li 3 4 3/2 16.5483 92.5 24.8224 12C 6 6 0 0 98.90 0 13C 6 7 1/2 10.7084 1.10 16.0621 16O 8 8 0 0 99.762 0 17O 8 9 5/2 5.7743 0.038 8.6614 19F 9 10 1/2 40.0776 100 60.1164 23Na 11 12 3/2 11.2686 100 16.9029 31P 15 16 1/2 17.2514 100 25.8771 Adapt ed f rom Mills I, ed. Quant it ies, unit s, and sy m bols in phy sic al c hem ist r y . Int ernat ional Union of Pure and Applied Chemist ry , Phy sic al Chemist ry Div ision. Oxf ord, UK: Blac kw ell Sc ienc e, 1989. Anot her w ay t o v isualize t his net magnet izat ion is t o rec all t hat t he indiv idual

spins prec ess about t he magnet ic f ield. When t he spins absorb energy , t his prec essional mot ion c ont inues but bec omes more c omplic at ed t o desc ribe. A usef ul t ec hnique t o simplif y t he desc ript ion is c alled a rot at ing f rame of ref erenc e, or rot at ing c oordinat e sy st em. In a rot at ing f rame, t he c oordinat e sy st em rot at es about one axis w hile t he ot her t w o axes v ary w it h t ime. By c hoosing a suit able axis and rat e of rot at ion f or t he c oordinat e sy st em, t he mov ing objec t appears st at ionary . F or MR experiment s, a c onv enient rot at ing f rame uses t he z axis, parallel t o B 0, as t he axis of rot at ion w hile t he x and y axes rot at e at t he Larmor f requenc y , П‰ 0. When v iew ed in t his f ashion, t he prec essing spin appears st at ionary in spac e w it h a f ixed set of x, y , and z c oordinat es. If t he ent ire c ollec t ion of prot ons in t he t issue v olume is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 93 examined, a c omplet e range of x and y v alues w ill be f ound, bot h posit iv e and negat iv e, but only t w o z v alues. T here w ill be an equal number of posit iv e and negat iv e x and y v alues, but a slight exc ess of posit iv e z v alues, as just desc ribed. If a v ec t or sum is perf ormed on t his c ollec t ion of prot ons, t he x and y c omponent s sum t o zero but a nonzero, posit iv e z c omponent w ill be lef t , t he net magnet izat ion M 0. In addit ion, sinc e t he z axis is t he axis of rot at ion, M 0 does not v ary w it h t ime. Regardless of w het her a st at ionary or f ixed c oordinat e sy st em is used, M 0 is of f ixed amplit ude and is parallel t o t he main magnet ic f ield. F or all subsequent disc ussions in t his book, a rot at ing f rame of ref erenc e w it h t he rot at ion axis parallel t o B 0 is used w hen desc ribing t he mot ion of t he prot ons.

F igure 2- 5 Mic rosc opic (A) and mac rosc opic (B) pic t ures of a c ollec t ion of prot ons in t he presenc e of an ext ernal magnet ic f ield. Eac h prot on prec esses about t he magnet ic f ield, B 0. If a rot at ing f rame of ref erenc e is used w it h a rot at ion rat e of ω 0, t hen t he c ollec t ion of prot ons appears st at ionary . While t he z c omponent s are one of t w o v alues (one posit iv e and one negat iv e), t he x and y c omponent s c an be any v alue, posit iv e or negat iv e. T he prot ons w ill appear t o t rac k along t w o “ c ones,” one w it h a posit iv e z c omponent and one w it h a negat iv e z c omponent . Bec ause t here are more prot ons in t he upper c one, t here w ill be a nonzero v ec t or sum, M 0, t he net magnet izat ion. It w ill be of c onst ant magnit ude and parallel t o B 0.

CONCEPTS OF MAGNETIC RESONANCE

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 94 T he MR experiment , in it s most basic f orm, c an be analy zed in t erms of energy t ransf er. During t he measurement , t he pat ient , or sample, is exposed t o energy at t he c orrec t f requenc y t hat w ill be absorbed. A short t ime lat er, t his energy is reemit t ed, at w hic h t ime it c an be det ec t ed and proc essed. A det ailed present at ion of t he proc esses inv olv ed in t his absorpt ion and reemission are bey ond t he sc ope of t his t ext . How ev er, a general desc ript ion of t he nat ure of t he molec ular int erac t ions is usef ul. In part ic ular, t he relat ionship bet w een t he molec ular pic t ure and t he mac rosc opic pic t ure prov ides an av enue f or t he explanat ion of t he princ iples of MR. T he f ormat ion of t he net magnet izat ion, M 0, by t he prot ons w it hin a sample w as desc ribed in t he prev ious sec t ion. T he ent ire f ield of MR is based on t he manipulat ion of M 0. T he simplest manipulat ion inv olv es t he applic at ion of a short burst , or pulse, of radiof requenc y (rf ) energy . T his pulse, also know n as an exc it at ion pulse, c ont ains many f requenc ies spread ov er a narrow range or bandw idt h. During t he pulse, t he prot ons absorb t he port ion of t his energy at a part ic ular f requenc y . F ollow ing t he pulse, t he prot ons reemit t he energy at t he same f requenc y . P.33 T he part ic ular f requenc y absorbed is proport ional t o t he magnet ic f ield B 0; t he equat ion relat ing t he t w o is t he Larmor equat ion, Eq. 1.

F igure 2- 6 Energy absorpt ion (mic rosc opic ). T he dif f erenc e in energy ОґE bet w een t he t w o c onf igurat ions (spin up and spin dow n) is proport ional t o t he magnet ic f ield st rengt h B0 and t he c orresponding prec essional f requenc y П‰ 0. When energy at t his f requenc y is applied, a spin f rom t he low er energy

st at e is exc it ed t o t he upper energy st at e. Also, a spin f rom t he upper energy

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 95 st at e is st imulat ed t o giv e up it s energy and relax t o t he low er energy st at e. Bec ause t here are more spins in t he low er energy st at e, t here is a net absorpt ion of energy by t he spins in t he sample.

T he f requenc y of energy absorbed by an indiv idual prot on is def ined v ery prec isely by t he magnet ic f ield t hat t he prot on experienc es due t o t he quant ized nat ure of t he spin v alues. When a prot on is irradiat ed w it h energy of t he c orrec t f requenc y (П‰ 0), it w ill be exc it ed f rom t he low er energy (spin up) orient at ion t o t he higher energy (spin dow n) orient at ion (F ig. 2- 6). At t he same t ime, a prot on in t he higher energy lev el w ill be st imulat ed t o release it s energy and w ill go t o t he low er energy lev el. T he energy dif f erenc e (Оґ,E) bet w een t he t w o lev els is exac t ly proport ional t o t he f requenc y П‰ 0 and t hus t he magnet ic f ield B 0. Only energy at t his f requenc y st imulat es t ransit ions bet w een t he spin up and spin dow n energy lev els. T his quant ized energy absorpt ion is know n as resonanc e absorpt ion and t he f requenc y of energy is know n as t he resonant f requenc y . Alt hough an indiv idual prot on absorbs t he rf energy , it is more usef ul t o disc uss t he resonanc e c ondit ion by examining t he ef f ec t of t he energy absorpt ion on t he net magnet izat ion, M 0. T he energy is applied as an rf pulse w it h a c ent ral f requenc y П‰ 0 and an orient at ion perpendic ular t o B 0, as indic at ed by an ef f ec t iv e f ield B 1 (F ig. 2- 7). T his orient at ion dif f erenc e allow s a c oupling bet w een t he rf pulse and M 0 so t hat energy c an be t ransf erred t o t he prot ons. Absorpt ion of t he rf energy of f requenc y П‰ 0 c auses M 0 t o rot at e aw ay f rom it s equilibrium orient at ion. T he direc t ion of rot at ion of M 0 is perpendic ular t o bot h B 0 and B 1. If t he t ransmit t er is lef t on long enough and at a high enough amplit ude, t he absorbed energy c auses M 0 t o rot at e ent irely int o t he t ransv erse plane, a result know n as a 90- degree pulse. When v iew ed in a rot at ing f rame, t he mot ion of M 0 is a simple v ec t or rot at ion; how ev er, t he end result is t he same w het her a rot at ing or st at ionary f rame of ref erenc e is used. When t he t ransmit t er is t urned of f , t he prot ons immediat ely begin t o realign t hemselv es and ret urn t o t heir original equilibrium orient at ion. T hey emit energy at f requenc y П‰ 0 as t hey do so t hrough a proc ess know n as relaxat ion. In addit ion, M 0 begins t o prec ess about B 0, similar t o t he behav ior

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 96 of a gy rosc ope w hen t ilt ed aw ay f rom t he v ert ic al axis. If a loop of w ire (rec eiv er) is plac ed perpendic ular t o t he t ransv erse plane, t he prot ons induc e a v olt age in t he w ire during t heir prec ession. T his induc ed v olt age, t he MR signal, is know n as t he f ree induc t ion dec ay (F ID) (F ig. 2- 8A). T he init ial magnit ude of t he F ID signal depends on t he v alue of M 0 immediat ely prior t o t he 90- degree pulse. T he F ID dec ay s w it h t ime as more of t he prot ons giv e up t heir absorbed energy t hrough a proc ess know n as relaxat ion (see below ), and t he c oherenc e, or unif ormit y , of t he prot on mot ion is lost .

F igure 2- 7 Energy absorpt ion (mac rosc opic ). In a rot at ing f rame of ref erenc e, t he rf pulse broadc ast at t he resonant f requenc y П‰ 0 c an be t reat ed as an addit ional magnet ic f ield, B 1, orient ed perpendic ular t o t he main magnet ic f ield, B 0. When energy is applied at t he appropriat e f requenc y , t he prot ons absorb it and t he net magnet izat ion, M, rot at es int o t he t ransv erse plane. T he direc t ion of rot at ion is perpendic ular t o bot h B 0 and B 1. T he amount of result ing rot at ion of M is know n as t he pulse f lip angle.

In general, t hree aspec t s of an MR signal are of int erest : it s magnit ude, or amplit ude, it s f requenc y , and it s phase relat iv e t o t he rf t ransmit t er phase (F ig. 2- 9). As ment ioned prev iously , t he signal magnit ude is relat ed t o t he v alue of M 0 immediat ely prior t o t he rf pulse. T he signal f requenc y is relat ed t o t he magnet ic f ield inf luenc ing t he prot ons. If all t he prot ons w ere t o experienc e t he same magnet ic f ield, B 0, t hen only one f requenc y w ould be present w it hin t he F ID. In realit y , t here are many magnet ic f ields t hroughout t he magnet , and t hus, many MR signals at many f requenc ies f ollow ing t he rf pulse. T hese signals are superimposed so t hat t he F ID c ont ains many

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 97 f requenc ies v ary ing as a f unc t ion of t ime. It is easier t o analy ze suc h a mult ic omponent signal in t erms of f requenc y rat her t han of t ime. T he c onv ersion of t he signal amplit udes f rom a f unc t ion of t ime t o a f unc t ion of f requenc y is ac c omplished using a mat hemat ic al operat ion c alled t he F ourier t ransf ormat ion. In t he f requenc y present at ion or f requenc y domain spec t rum, t he MR signal is mapped ac c ording t o it s f requenc y relat iv e t o a ref erenc e f requenc y , t y pic ally t he t ransmit t er f requenc y П‰ TR. F or sy st ems using quadrat ure det ec t ors (see sec t ion on hardw are), П‰ TR is c ent ered in t he display w it h f requenc ies higher and low er t han П‰ TR loc at ed t o t he lef t P.34 and right , respec t iv ely (F ig. 2- 8B). T he f requenc y domain t hus allow s a simple w ay t o examine t he magnet ic env ironment t hat a prot on experienc es. T his simplif ic at ion is not w it hout a penalt y . Use of t he F ourier t ransf ormat ion c auses loss of t he abilit y t o direc t ly relat e signal int ensit ies t o t he number of prot ons produc ing t he signal. How ev er, t he signal int ensit y c an be relat ed f rom one f requenc y t o anot her w it hin t he same measurement ; t hat is, only relat iv e signal int ensit ies c an be c ompared.

F igure 2- 8 F ree induc t ion dec ay , real and imaginary . A: T he response of t he net magnet izat ion, M, t o an rf pulse as a f unc t ion of t ime is know n as t he f ree induc t ion dec ay (F ID). It is proport ional t o t he amount of t ransv erse magnet izat ion generat ed by t he pulse. T he F ID is maximized w hen using a 90degree exc it at ion pulse. B: F ourier t ransf ormat ion of (A), magnit ude and phase. T he F ourier t ransf ormat ion is used t o c onv ert t he digit al v ersion of t he MR signal (F ID) f rom a f unc t ion of t ime t o a f unc t ion of f requenc y . Signals measured w it h a quadrat ure det ec t or are display ed w it h t he t ransmit t er

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 98 (ref erenc e) f requenc y П‰ TR in t he middle of t he display . T he Ny quist f requenc y П‰ NQ below and abov e П‰ TR are t he minimum and maximum f requenc ies of t he f requenc y display , respec t iv ely . F or hist oric al reasons, f requenc ies are plot t ed w it h low er f requenc ies on t he right side and higher f requenc ies on t he lef t side of t he display .

Sinc e t he prot on prec ession is c ont inuous, t he MR signal is c ont inuous, or analog, in nat ure. How ev er, post proc essing t ec hniques, suc h as F ourier t ransf ormat ion, require a digit al represent at ion of t he signal. T o produc e a digit al v ersion, t he F ID signal is measured, or sampled, using an analog- t odigit al c onv ert er (ADC). In most inst anc es, t he resonant f requenc ies of prot ons are great er t han many ADCs c an proc ess. F or t his reason, a phasec oherent dif f erenc e signal is generat ed based on t he f requenc y and phase of t he input rf pulse; t hat is, t he signal ac t ually digit ized is t he measured signal relat iv e t o П‰ TR. Under normal c ondit ions, t his so- c alled demodulat ed signal is digit ized f or a predet ermined t ime, know n as t he sampling t ime, and w it h a user- selec t able number of dat a point s. In suc h a sit uat ion, t here w ill be a maximum f requenc y , know n as t he Ny quist f requenc y П‰ NQ, t hat c an be ac c urat ely measured:

In MR, t he Ny quist f requenc y c an be 500 t o 500,000 Hz, depending on t he c ombinat ion of sampling t ime and number of dat a point s. T o exc lude f requenc ies great er t han t he Ny quist limit f rom t he signal, a f ilt er know n as a low - pass f ilt er is used prior t o digit izat ion. F requenc ies exc luded by t he low pass f ilt er are usually noise, so t hat f ilt ering prov ides a met hod f or improv ing t he signal- t o- noise rat io (S/N) f or t he measurement . T he opt imum S/N is usually obt ained by inc reasing t he sampling t ime t o mat c h t he Ny quist f requenc y and low - pass f ilt er w idt h f or t he part ic ular measurement c ondit ions. F or quadrat ure det ec t ion sy st ems t y pic ally used in MR, t he t ot al rec eiv er bandw idt h is 2 Г—П‰ NQ c ent ered about П‰ TR (F ig. 2- 8B).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications 99

F igure 2- 9 Planar (lef t ) and c irc ular (r ight ) represent at ions of a t ime- v ary ing w av e. T he amplit ude (a) is t he maximum dev iat ion of t he w av e f rom it s mean v alue. T he period (b) is t he t ime required f or c omplet ion of one c omplet e c y c le of t he w av e. T he f requenc y of t he w av e is t he rec iproc al of t he period. T he phase or phase angle of t he w av e (c ) desc ribes t he shif t in t he w av e relat iv e t o a ref erenc e (a sec ond w av e f or t he planar represent at ion, horizont al axis f or c irc ular represent at ion). T he t w o plane w av es display ed hav e t he same amplit ude and period (f requenc y ), but hav e a phase dif f erenc e of ПЂ/4 or 90 degrees.

T he spec if ic f requenc y t hat a prot on absorbs is dependent on magnet ic f ields arising f rom t w o sourc es. One is t he applied magnet ic f ield, B 0. T he ot her one is molec ular in origin and produc es t he c hemic al shif t . In pat ient s, t he bulk of t he hy drogen MR signal arises f rom t w o sourc es, w at er and f at . Wat er has t w o hy drogen at oms bonded t o P.35 one oxy gen at om w hile f at has many hy drogen at oms bonded t o a long c hain c arbon f ramew ork (t y pic ally 10 t o 18 c arbon at oms in lengt h). Bec ause of it s dif f erent molec ular env ironment , a hy drogen at om in f at has a dif f erent loc al magnet ic f ield t han one in w at er. Dif f erent resonant f requenc ies are measured f rom f at and w at er prot ons under t he inf luenc e of t he same main magnet ic f ield. A c onv enient sc ale t o express t hese f requenc y dif f erenc es is t he part s per million (ppm) sc ale, w hic h is t he resonant f requenc y of t he hy drogen at om of int erest relat iv e t o a ref erenc e f requenc y . F requenc y dif f erenc es expressed in t his f orm are know n as c hemic al shif t s. While t he c hoic e of ref erenc e f requenc y is arbit rary , it is c onv enient t o use П‰ TR as t he ref erenc e. T he primary adv ant age of t he ppm sc ale is t hat f requenc y dif f erenc es are

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications100 independent of B 0. F or f at and w at er, t he dif f erenc e in c hemic al shif t s at all f ield st rengt hs is approximat ely 3.5 ppm, w it h f at at a low er f requenc y . At 1.5 T , t his dif f erenc e is 220 Hz, w hereas at 3.0 T , it is 450 Hz (F ig. 2- 10). T he c hemic al shif t dif f erenc e bet w een f at and w at er c an be v isualized in t he rot at ing f rame. A 150- Hz dif f erenc e in f requenc y means t hat t he f at resonanc e prec esses slow er t han t he w at er resonanc e by 6.7 ms per c y c le (1/150 Hz). T he f at resonanc e w ill align w it h or be in phase w it h t he w at er resonanc e ev ery 6.7 ms at 1.0 T . F or a 1.5- T MR sy st em, t he same c y c ling oc c urs ev ery 4.5 ms (1/220 Hz), and it oc c urs ev ery 2.25 ms f or a 3.0- T sy st em (F ig. 2- 11). T he 3.5- ppm c hemic al shif t dif f erenc e ment ioned prev iously is an approximat e dif f erenc e. T he f at resonanc e signal is a c omposit e f rom all t he prot ons w it hin t he f at molec ule. T he part ic ular c hemic al c omposit ion (e.g., sat urat ed v ersus unsat urat ed hy droc arbon c hain, lengt h of hy droc arbon c hain) det ermines t he exac t resonant f requenc y f or t his c omposit e signal. T he 3.5- ppm dif f erenc e applies t o t he majorit y of f at t y t issues f ound in t he body . Chemic al shif t dif f erenc es bet w een prot ons in dif f erent molec ular env ironment s prov ide t he basis f or MR spec t rosc opy , w hic h is desc ribed in more det ail in t he sec t ion on MR spec t rosc opy .

F igure 2- 10 Spec t rum of w at er and f at at 1.5 T (lef t ) and 3.0 T (r ight ). T he resonant f requenc ies f or w at er and f at are separat ed by approximat ely 3.5 ppm, w hic h c orresponds t o an absolut e f requenc y dif f erenc e of 225 Hz f or a 1.5- T magnet ic f ield (63 MHz) and 450 Hz f or a magnet ic f ield of 3.0 T (126 MHz).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications101 RELAXATION As ment ioned prev iously , t he MR measurement c an be analy zed in t erms of energy t ransf er. Relaxat ion is t he proc ess by w hic h t he spins release t he energy t hat t hey absorbed f rom t he rf pulse. Relaxat ion is a f undament al proc ess in MR, as essent ial as energy absorpt ion, and prov ides t he primary mec hanism f or image c ont rast , as disc ussed lat er. In resonanc e absorpt ion, rf energy is absorbed by t he spins only w hen it is broadc ast at t he c orrec t f requenc y . T he addit ional energy dist urbs t he equilibrium arrangement of spins parallel and ant iparallel t o B. F ollow ing exc it at ion, relaxat ion oc c urs, in w hic h t he spins release t his added energy and ret urn t o t heir original c onf igurat ion t hrough nat urally oc c urring proc esses. Alt hough an indiv idual spin absorbs t he energy , relaxat ion t imes are measured f or an ent ire sample and are st at ist ic al or av erage measurement s; t hat is, relaxat ion t imes are measured f or liv er or spleen as bulk samples rat her t han f or t he indiv idual w at er or f at molec ules w it hin t he organs. T w o relaxat ion t imes c an be measured, know n as T 1 and T 2. While bot h t imes measure t he spont aneous energy t ransf er by an exc it ed prot on, t hey dif f er in t he f inal disposit ion of t he energy .

T1 Relaxation and Saturation T he relaxat ion t ime T 1 is t he t ime required f or t he z c omponent of M t o ret urn t o 63% of it s original v alue f ollow ing an exc it at ion pulse. It is also know n as t he spin- lat t ic e relaxat ion t ime or longit udinal relaxat ion t ime. As ment ioned in t he prev ious sec t ion, M 0 is parallel t o B 0 at equilibrium, and energy absorpt ion rot at es M 0 int o t he t ransv erse plane. T 1 relaxat ion prov ides t he means by w hic h t he prot ons giv e up t heir energy t o ret urn t o t heir original orient at ion. If a 90- degree pulse is applied t o a sample, M 0 w ill rot at e as illust rat ed in F igure 2- 7, and t here w ill be no longit udinal magnet izat ion present f ollow ing t he pulse. As t ime goes on, a ret urn of t he longit udinal magnet izat ion w ill be observ ed as t he prot ons release t heir energy (F ig. 2- 12). T his ret urn of magnet izat ion f ollow s an exponent ial grow t h proc ess, w it h T 1 being t he t ime c onst ant desc ribing t he rat e of grow t h. Af t er t hree T 1 t ime periods, M w ill hav e ret urned t o 95% of it s v alue prior t o t he exc it at ion pulse, M 0. T he t erm “ spin-lat t ic e” ref ers t o t he f ac t t hat t he exc it ed prot on (spin) t ransf ers

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications102 it s energy t o it s surroundings (lat t ic e) rat her t han t o anot her spin. T he energy no longer c ont ribut es t o spin exc it at ion. T his energy t ransf er t o t he surroundings has some v ery import ant c onsequenc es. Suppose t he rf energy is c ont inuously applied at t he resonant f requenc y so t hat no relaxat ion oc c urs. A c omparison of t he mic rosc opic and mac rosc opic pic t ures is usef ul at t his point . In t he mic rosc opic pic t ure, t he prot ons in t he low er energy lev el absorb t he rf energy , and t he prot ons in t he upper energy lev el are st imulat ed t o emit t heir energy . Bec ause energy is c ont inuously t ransmit t ed, t he prot on populat ions of t he P.36 t w o lev els gradually equalize. When t his equalizat ion oc c urs, no f urt her net absorpt ion of energy is possible, a c ondit ion know n as sat ur at ion. In t he mac rosc opic pic t ure, M rot at es c ont inuously but gradually get s smaller in magnit ude unt il it disappears as t he net populat ion dif f erenc e approac hes zero. Bec ause t here is no net magnet izat ion, t here is no c oherenc e of prot on mot ion in t he t ransv erse plane and t hus no signal is produc ed. A c ollec t ion of prot ons c an absorb only a limit ed amount of energy bef ore t hey bec ome sat urat ed.

F igure 2- 11 Prec ession of f at and w at er prot ons. Bec ause of t he 3.5- ppm f requenc y dif f erenc e, a f at prot on prec esses at a slow er f requenc y t han a w at er prot on. In a rot at ing f rame at t he w at er resonanc e f requenc y , t he f at

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications103 prot on c y c les in and out of phase w it h t he w at er prot on. F ollow ing t he exc it at ion pulse, t he t w o prot ons are in phase (A). Af t er a short t ime, t hey w ill be 180 degrees out of phase (B), t hen in phase (C), t hen 180 degrees out of phase (D), t hen in phase (E). T he c ont ribut ion of f at t o t he t ot al signal f luc t uat es and depends on w hen t he signal is det ec t ed. At 1.5 T , t he inphase t imes are 0 (A), 4.5 (C), and 9 (E) ms, and t he out - of - phase t imes are 2.25 (B) and 6.7 (D) ms. At 3.0 T , t he in- phase t imes are 0, 2.25, and 4.5 ms, and t he out - of - phase t imes are 1.12 and 3.4 ms, respec t iv ely .

F igure 2- 12 T 1 relaxat ion c urv e. F ollow ing a 90- degree rf pulse, t here is no longit udinal magnet izat ion. A short t ime lat er, longit udinal magnet izat ion w ill be observ ed as t he prot ons release t heir energy t hrough T 1 relaxat ion. Gradually , as more prot ons release t heir energy , a larger f rac t ion of t he z c omponent of t he net magnet izat ion, M Z , is reest ablished. Ev ent ually , t he init ial net magnet izat ion, M 0, w ill be rest ored c omplet ely . T he c hange in M Z /M 0 w it h t ime T R f ollow s an exponent ial grow t h proc ess. T he t ime c onst ant f or t his proc ess is T 1, t he spin- lat t ic e relaxat ion t ime, and is t he t ime w hen M Z has ret urned t o 63% of it s original v alue.

In a modern MR experiment , pulsed rf energy is applied t o t he prot ons repeat edly w it h a delay t ime bet w een t he pulses. T his t ime bet w een pulses allow s t he exc it ed prot ons t o giv e up t he absorbed energy (T 1 relaxat ion). As t he prot ons giv e up t his energy t o t heir surroundings, t he populat ion dif f erenc e (spin up v ersus spin dow n) is reest ablished so t hat net absorpt ion c an reoc c ur af t er t he next pulse. In t he mac rosc opic pic t ure, M ret urns

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications104 t ow ard it s init ial v alue M 0 as more energy is dissipat ed. Sinc e M is t he ult imat e sourc e of t he MR signal, t he more energy is dissipat ed, t he more signal is generat ed f ollow ing t he next rf pulse. F or prac t ic al reasons, t he t ime bet w een suc c essiv e rf pulses is usually insuf f ic ient f or c omplet e T 1 relaxat ion so t hat M w ill not be c omplet ely rest ored t o M 0. Applic at ion of a sec ond rf pulse prior t o c omplet e relaxat ion w ill rot at e M int o t he t ransv erse plane, but w it h a smaller magnit ude t han f ollow ing t he f irst rf pulse. T he f ollow ing experiment desc ribes t he sit uat ion (F ig. 2- 13): · A 90- degree rf pulse is applied. M is rot at ed int o t he t ransv erse plane. · A repet it ion t ime, T R, elapses, insuf f ic ient f or c omplet e T 1 relaxat ion. T he longit udinal magnet izat ion at t he end of T R, M′, is less t han in (a). · A sec ond 90- degree rf pulse is applied. M′ is rot at ed int o t he t ransv erse plane. · Af t er a sec ond t ime T R elapses, M” is produc ed. It is smaller in magnit ude t han M′, but t he dif f erenc e is less t han t he dif f erenc e bet w een M and M′.

F igure 2- 13 F ollow ing a 90- degree rf pulse, longit udinal magnet izat ion is regenerat ed t hrough T 1 relaxat ion. If t he t ime bet w een suc c essiv e rf pulses, T R, is insuf f ic ient f or c omplet e rec ov ery of t he net magnet izat ion, M, t hen only M′ w ill be present at t he t ime of t he next rf pulse (a). If t ime TR elapses again, t hen only M″ w ill be present (b). M″ w ill be smaller t han M′ but t he dif f erenc e w ill be less t han t he dif f erenc e bet w een M and M′.

P.37

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications105 F ollow ing a f ew repet it ions, M ret urns t o t he same magnit ude prior t o eac h rf pulse; t hat is, M ac hiev es a st eady - st at e v alue. In general, t his st eady - st at e v alue depends on f iv e paramet ers: · T he main magnet ic f ield B 0. T he larger t he v alue f or B 0, t he larger M. · T he number of prot ons produc ing M (per unit v olume of t issue, know n as t he prot on densit y ); · T he amount of energy absorbed by t he prot ons (t he pulse angle or f lip angle). · T he rat e of rf pulse applic at ion (T R). · T he ef f ic ienc y of t he prot ons in releasing t heir energy (T 1 relaxat ion t ime). F or many MRI experiment s, suc h as st andard spin ec ho and gradient ec ho imaging, a st eady st at e of M is present bec ause mult iple rf pulses are applied and t he repet it ion t ime, T R, bet w een t he pulses is nearly alw ay s less t han suf f ic ient f or c omplet e relaxat ion. T o produc e t his st eady st at e prior t o dat a c ollec t ion, addit ional rf pulses are applied t o t he t issue immediat ely prior t o t he main imaging pulses. T hese ext ra rf pulses are know n as preparat ory pulses or dummy pulses bec ause t he generat ed signals are usually ignored. T hese preparat ory pulses ensure t hat M has t he same magnit ude prior t o ev ery measurement during t he sc an. As ment ioned earlier, spin- lat t ic e relaxat ion measures energy t ransf er f rom an exc it ed prot on t o it s surroundings. T he key t o t his energy t ransf er is t he presenc e of some t y pe of molec ular mot ion (e.g., v ibrat ion, rot at ion) in t he v ic init y of t he exc it ed prot on w it h an int rinsic f requenc y П‰ L t hat mat c hes t he resonant f requenc y , П‰ 0. T he c loser П‰ 0 is t o П‰ L, t he more readily t he mot ion absorbs t he energy and t he more f requent ly t his energy t ransf er oc c urs, allow ing t he c ollec t ion of prot ons t o ret urn t o it s equilibrium c onf igurat ion sooner. In t issues, t he nat ure of t he prot ein molec ular st ruc t ure and any met al ions t hat may be present hav e a pronounc ed ef f ec t on t he part ic ular П‰ L. Met als ions, suc h as iron or manganese, c an hav e signif ic ant magnet ic moment s t hat may inf luenc e t he loc al env ironment . While t he part ic ular prot ein st ruc t ures are dif f erent f or many t issues, t he molec ular rot at ion, or t umbling, of most prot eins t y pic ally has an П‰ L of approximat ely 1 MHz. T heref ore, at higher resonant f requenc ies (higher B 0), t here is a poorer mat c h bet w een П‰ L and П‰ 0. T his enables a less ef f ic ient energy

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications106 t ransf er t o oc c ur, and t hus T 1 is longer. T his is t he basis f or t he f requenc y dependenc e of T 1; namely , t hat T 1 inc reases w it h inc reasing magnet ic f ield st rengt h. T his is also t he reason t hat a larger B 0 does not nec essarily t ranslat e t o a great er signal, as sat urat ion is more prev alent due t o t he longer T 1 t imes.

T2 Relaxation, T2* Relaxation, and Spin Echoes T he relaxat ion t ime T 2 is t he t ime required f or t he t ransv erse c omponent of M t o dec ay t o 37% of it s init ial v alue v ia irrev ersible proc esses. It is also know n as t he spin–spin relaxat ion t ime or t ransv erse relaxat ion t ime. As ment ioned earlier, M 0 is orient ed only along t he z (B 0) axis at equilibrium and no port ion of M 0 is in t he xy plane. T he c oherenc e is ent irely longit udinal. Absorpt ion of energy f rom a 90- degree rf pulse, as in F igure 2- 7, c auses M 0 t o rot at e ent irely int o t he xy plane, so t hat t he c oherenc e is in t he t ransv erse plane at t he end of t he pulse. As t ime elapses, t his c oherenc e disappears w hile, at t he same t ime, t he prot ons release t heir energy and reorient t hemselv es along B 0. T his disappearing c oherenc e produc es t he F ID desc ribed prev iously . As t his c oherenc e disappears, t he v alue of M in t he xy plane dec reases t ow ard zero. T 2, or T 2*, relaxat ion is t he proc ess by w hic h t his t ransv erse magnet izat ion is lost . A c omparison of t he mic rosc opic and mac rosc opic pic t ures prov ides addit ional insight . At t he end of t he 90- degree rf pulse, w hen t he prot ons hav e absorbed energy and are orient ed in t he t ransv erse plane, eac h prot on prec esses at t he same f requenc y , ω 0, and is sy nc hronized at t he same point or phase of it s prec essional c y c le. Sinc e a nearby prot on of t he same t y pe has t he same molec ular env ironment and t he same ω 0, it c an readily absorb t he energy t hat is being released by it s neighbor. Spin–spin relaxat ion ref ers t o t his energy t ransf er f rom an exc it ed prot on t o anot her nearby prot on (F ig. 2- 14). T he absorbed energy remains as spin exc it at ion rat her t han being t ransf erred t o t he surroundings, as in T 1 relaxat ion. T his prot on–prot on energy t ransf er c an oc c ur many t imes as long as t he prot ons are in c lose proximit y and remain at t he same ω 0. Int ermolec ular and int ramolec ular int erac t ions, suc h as v ibrat ions and rot at ions, c ause ω 0 t o f luc t uat e. T his f luc t uat ion produc es a gradual, irrev ersible loss of phase c oherenc e t o t he spins as t hey exc hange

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications107 t he energy and reduc e t he magnit ude of t he t ransv erse magnet izat ion and t he generat ed signal (F ig. 2- 15). T 2 is t he t ime w hen t he t ransv erse magnet izat ion is 37% of it s v alue immediat ely af t er t he 90- degree pulse, w hen t his irrev ersible proc ess is t he only c ause f or t he loss of c oherenc e. As more t ime elapses, t his t ransv erse P.38 c oherenc e c omplet ely disappears, only t o ref orm in t he longit udinal direc t ion as T 1 relaxat ion oc c urs. T his dephasing t ime, T 2, is alw ay s less t han or equal t o T 1.

F igure 2- 14 Spin–spin relaxat ion. A: T w o w at er molec ules. One spin on one molec ule has absorbed rf energy and is exc it ed (spin dow n). B: If t he spins are in c lose proximit y , t he energy c an be t ransf erred f rom t he f irst molec ule t o a spin on t he sec ond molec ule.

T here are sev eral pot ent ial c auses f or a loss of t ransv erse c oherenc e t o M. One is t he mov ement of t he adjac ent spins due t o molec ular v ibrat ions or rot at ions. T his mov ement is responsible f or spin–spin relaxat ion, or t he t rue T 2. Anot her c ause arises f rom t he f ac t t hat a prot on nev er experienc es a magnet ic f ield t hat is 100% unif orm or homogeneous. As t he prot on prec esses, it experienc es a f luc t uat ing loc al magnet ic f ield, c ausing a c hange in ω 0 and a loss in t ransv erse phase c oherenc e. T his nonunif ormit y in B 0 c omes f rom t hree sourc es:

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications108 Main f ield inhom ogeneit y . T here is alw ay s some degree of nonunif ormit y t o B 0 due t o imperf ec t ions in magnet manuf ac t uring, c omposit ion of nearby building w alls, or ot her sourc es of met al. T his f ield dist ort ion is c onst ant during t he measurement t ime. Sam ple-induc ed inhom ogeneit y . Dif f erenc es in t he magnet ic susc ept ibilit y or degree of magnet ic polarizat ion of adjac ent t issues (e.g., bone, air) dist ort t he loc al magnet ic f ield near t he int erf ac e bet w een t he dif f erent t issues. P.39 T his inhomogeneit y is of c onst ant magnit ude and is present as long as t he pat ient is present w it hin t he magnet .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications109 F igure 2- 15 A: A rot at ing f rame slow er t han ω 0 is assumed f or t his f igure. T he net magnet izat ion, M (ar r ow ) is orient ed parallel t o B 0 (not show n) prior t o t he pulse (1). F ollow ing a 90- degree rf pulse, t he prot ons init ially prec ess in phase in t he t ransv erse plane (2). Due t o int er- and int ramolec ular int erac t ions, t he prot ons begin t o prec ess at dif f erent f requenc ies (dashed ar r ow , f ast er; dot t ed ar r ow , slow er) and bec ome asy nc hronous w it h eac h ot her (3). As more t ime elapses (4,5), t he t ransv erse c oherenc e bec omes smaller unt il t here is c omplet e randomness of t he t ransv erse c omponent s and no c oherenc e (6). B: Plot of t he relat iv e xy c omponent of t he net magnet izat ion, M XY, as a f unc t ion of t he ec ho t ime. T he numbers c orrespond t o t he expec t ed M XY c omponent f rom F igure 2- 15A. T he c hange in M XY/M XYmax w it h t ime f ollow s an exponent ial dec ay proc ess. T he t ime c onst ant f or t his proc ess is t he spin–spin relaxat ion t ime T 2 and is t he t ime w hen M XY has dec ay ed t o 37% of it s original v alue.

Im aging gr adient s. As disc ussed in t he next sec t ion, t he t ec hnique used f or spat ial loc alizat ion generat es a magnet ic f ield inhomogeneit y t hat induc es prot on dephasing. T his inhomogeneit y is t ransient during t he measurement . Proper design of t he pulse sequenc e eliminat es t he imaging gradient s as a sourc e of dephasing. T he ot her sourc es t hat c ont ribut e t o t he t ot al t ransv erse relaxat ion t ime, T 2* , inc lude t he dephasing due t o t he main f ield inhomogeneit y and magnet ic susc ept ibilit y dif f erenc es. T he dec ay of t he t ransv erse magnet izat ion f ollow ing a 90- degree rf pulse, t he F ID, f ollow s an exponent ial proc ess w it h a t ime c onst ant of T 2* rat her t han T 2. F or most t issues or liquids, main f ield inhomogeneit y is t he major f ac t or det ermining T 2* , w hereas f or t issue w it h signif ic ant iron deposit s or air- f illed c av it ies, magnet ic susc ept ibilit y dif f erenc es predominat e T 2* . Some sourc es of prot on dephasing c an be rev ersed by t he applic at ion of a 180- degree rf pulse, w hic h is desc ribed by t he f ollow ing sequenc e of ev ent s (F ig. 2- 16): · A 90- degree rf pulse; · A short delay of t ime, t ; · A 180- degree rf pulse; and · A sec ond t ime delay , t . T he init ial 90- degree rf pulse rot at es M 0 int o t he t ransv erse plane. During t he t ime t , prot on dephasing oc c urs t hrough T 2* relaxat ion proc esses and t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications110 t ransv erse c oherenc e diminishes. Applic at ion of t he 180- degree rf pulse c auses t he prot ons t o rev erse t heir phases relat iv e t o t he resonant f requenc y . T he rat es and direc t ions of prec ession f or t he prot ons do not c hange, only t heir relat iv e phase. If t ime t elapses again, t hen t he prot ons w ill regain t heir t ransv erse c oherenc e. T his ref ormat ion of phase c oherenc e induc es anot her signal in t he rec eiv er c oil, know n as a spin ec ho. Sourc es of dephasing t hat do not c hange during t he t w o t ime periods, t he main f ield inhomogeneit y and magnet ic susc ept ibilit y dif f erenc es, are eliminat ed bec ause t he prot ons experienc e exac t ly t he same int erac t ions prior t o and f ollow ing t he 180- degree pulse. T his means t hat t he c ont ribut ions t o T 2* relaxat ion f rom t hese st at ic sourc es disappear. Only t he irrev ersible spin–spin relaxat ion is unaf f ec t ed by t he 180- degree rf pulse, so t hat t he loss of phase c oherenc e and signal amplit ude f or a spin ec ho is due only t o t rue T 2 relaxat ion. F ollow ing ec ho f ormat ion, t he prot ons c ont inue t o prec ess and dephase a sec ond t ime as t he sourc es of dephasing c ont inue t o af f ec t t hem. Applic at ion of a sec ond 180- degree rf pulse again rev erses t he prot on phases and generat es anot her c oherenc e t o t he prot ons, produc ing anot her spin ec ho. T his sec ond ec ho dif f ers f rom t he f irst ec ho by t he P.40 great er amount of T 2 relaxat ion c ont ribut ing t o t he signal loss. T his proc ess of spin ec ho f ormat ion by 180- degree rf pulses c an be repeat ed as many t imes as desired, unt il T 2 relaxat ion c omplet ely dephases t he prot ons. T he use of mult iple 180- degree pulses maint ains phase c oherenc e t o t he prot ons longer t han t he use of a single 180- degree rf pulse bec ause of t he signif ic ant dephasing t hat t he f ield inhomogeneit y induc es ov er v ery short t ime periods.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications111

F igure 2- 16 A rot at ion f rame slow er t han ω 0 is assumed f or t his f igure. T he net magnet izat ion, M (ar r ow ), is orient ed parallel t o B 0 (not show n) prior t o t he pulse (A). Applic at ion of a 90- degree rf pulse rot at es M int o t he t ransv erse plane (B). Due t o T2* relaxat ion proc esses, t he prot ons bec ome asy nc hronous w it h eac h ot her during t he ec ho t ime (TE)/2 (C ). Applic at ion of a 180- degree rf pulse c auses t he prot ons t o rev erse t heir phase relat iv e t o t he t ransmit t er phase. T he prot ons t hat prec essed most rapidly are f art hest behind (dashed ar r ow ), w hile t he slow est prot ons are in f ront (dot t ed ar r ow ) (D). Allow ing t ime TE/2 t o elapse again allow s t he prot ons t o regain t heir phase c oherenc e in t he t ransv erse plane (E), generat ing a signal in t he rec eiv er c oil know n as a spin ec ho. T he loss in magnit ude of t he ref ormed c oherenc e relat iv e t o t he original c oherenc e (B) is due t o irrev ersible proc esses (i.e., t rue spin–spin or T2 relaxat ion).

One import ant dif f erenc e bet w een T 1 and T 2 relaxat ion is in t he inf luenc e of B 0. As ment ioned earlier, T 1 is v ery sensit iv e t o B 0, w it h longer T 1 t imes measured f or a t issue at higher v alues of B 0. T 2 is relat iv ely insensit iv e t o B0 at t he relat iv ely large f ield st rengt hs c urrent ly used in MRI. Only at v ery low v alues of B0 (less t han 0.05 T ) w ill t here be signif ic ant c hanges in T 2. T he ot her c omponent s of T 2* , main- f ield inhomogeneit y and magnet ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications112 susc ept ibilit y dif f erenc es, bec ome more prominent at higher v alues of B 0. Good magnet ic f ield unif ormit y is more dif f ic ult t o generat e at high magnet ic f ields. Larger v alues of B0 also c ause great er dif f erenc es in M 0 bet w een t w o t issues w it h dif f erent magnet ic susc ept ibilit ies. T he result is t hat T 2- w eight ed t ec hniques show lit t le sensit iv it y t o B 0, w hile T 2* - w eight ed t ec hniques show great er signal dif f erenc es at higher v alues of B 0.

PRINCIPLES OF MAGNETIC RESONANCE IMAGING T he relat ionship bet w een t he f requenc y of energy t hat a prot on absorbs and t he magnet ic f ield st rengt h t hat it experienc es w as desc ribed prev iously . MRI uses t his f ield dependenc e t o loc alize t hese prot on f requenc ies t o dif f erent regions of spac e. In MRI, t he magnet ic f ield is made spat ially dependent t hrough t he applic at ion of magnet ic f ield gradient s. T hese gradient s are small pert urbat ions superimposed on t he main magnet ic f ield B 0, w it h a t y pic al imaging gradient produc ing a t ot al f ield v ariat ion of less t han 1%. T hey are also linear pert urbat ions t o B 0, so t hat t he exac t magnet ic f ield is linearly dependent on t he loc at ion inside t he magnet . Gradient s are also applied f or short periods of t ime during a sc an and are ref erred t o as gradient pulses. In c linic al MRI, t he magnet ic f ield gradient s produc e linear v ariat ions primarily in one direc t ion only , one in eac h of t he x, y , and z direc t ions, know n as t he phy sic al gradient s. Eac h gradient is assigned, t hrough t he operat ing sof t w are, t o one or more of t he t hree “ logic al,” or f unc t ional, gradient s required t o obt ain an image: slic e selec t ion, readout (or f requenc y enc oding), and phase enc oding. T he part ic ular pairing of phy sic al and logic al gradient s is v ariable and depends on t he ac quisit ion paramet ers and pat ient posit ioning as w ell as t he part ic ular manuf ac t urer's c hoic e of phy sic al direc t ions. T he c ombinat ion of gradient pulses, rf pulses, dat a sampling periods, and t he t iming bet w een t hem t hat is used t o ac quire an image is know n as a pulse sequenc e. T he presenc e of magnet ic f ield gradient s requires an expanded v ersion of t he Larmor equat ion giv en in Eq. 1:

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications113 w here П‰ i is t he f requenc y of t he prot on at posit ion r i and G is a v ec t or represent ing t he t ot al gradient amplit ude and direc t ion. T he dimensions of G are expressed in eit her milliT esla per met er (mT /m) or Gauss per c ent imet er (G/c m), w here 1 G/c m = 10 mT /m. Equat ion 4 st at es t hat , in t he presenc e of a gradient f ield, eac h prot on w ill resonat e at a unique f requenc y t hat depends on it s exac t posit ion w it hin t he gradient f ield. T he MR image is simply a map of t he f requenc ies and phases of t he prot ons generat ed by unique magnet ic f ields at eac h point t hroughout t he image. T he display ed image c onsist s of digit al pic t ure element s (pixels) t hat represent v olume element s (v oxels) of t issue. T he pixel int ensit y is proport ional t o t he number of prot ons c ont ained w it hin t he v oxel w eight ed by t he T 1 and T 2 relaxat ion t imes f or t he t issues w it hin t he v oxel.

Slice Selection T he init ial st ep in MRI is t he loc alizat ion of t he rf exc it at ion t o a region of spac e, w hic h is ac c omplished t hrough t he use of f requenc y - selec t iv e exc it at ion in c onjunc t ion w it h a gradient know n as t he slic e selec t ion gradient , GSS . T he gradient direc t ion (x, y , or z) det ermines t he slic e orient at ion, w hile t he gradient amplit ude t oget her w it h c ert ain rf pulse c harac t erist ic s det ermines bot h t he slic e t hic kness and slic e posit ion. A f requenc y - selec t iv e rf pulse has t w o part s assoc iat ed w it h it : a c ent ral f requenc y and a narrow range or bandw idt h of f requenc ies (t y pic ally 1–2 kHz). When suc h a pulse is broadc ast in t he presenc e of G SS , a narrow region of t issue ac hiev es t he resonanc e c ondit ion (Eq. 4) and absorbs t he rf energy . T he durat ion of t he rf pulse and it s amplit ude det ermine t he amount of result ing prot on rot at ion (e.g., 90 degrees, 180 degrees). T he c ent ral f requenc y of t he pulse det ermines t he part ic ular loc at ion exc it ed by t he pulse w hen G SS is present . Dif f erent slic e posit ions are exc it ed by c hanging t he c ent ral f requenc y (F ig. 2- 17). T he slic e t hic kness is det ermined by t he gradient amplit ude GSS and t he bandw idt h of f requenc ies δE inc orporat ed int o t he rf pulse. T y pic ally , δE is f ixed so t hat t he slic e t hic kness is c hanged by modif y ing t he amplit ude of G SS w it h t hinner slic es requiring larger v alues of G SS (F ig. 2- 18). Onc e G SS det ermined, t he c ent er f requenc y is c alc ulat ed using Eq. 4 t o bring t he desired loc at ion int o resonanc e. Mult islic e imaging, t he most c ommonly used approac h f or MRI, uses t he same G SS but a unique rf pulse

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications114 during exc it at ion f or eac h slic e. Eac h rf pulse has t he same bandw idt h but a dif f erent c ent ral f requenc y , t hereby exc it ing a dif f erent region of t issue. T he slic e orient at ion is det ermined by t he part ic ular phy sic al gradient or gradient s def ined as t he logic al slic e selec t ion gradient . T he slic e orient at ion is def ined so t hat t he gradient direc t ion (direc t ion of magnet ic f ield v ariat ion) is P.41 perpendic ular or normal t o t he surf ac e of t he slic e, so t hat ev ery prot on w it hin t he slic e experienc es t he same t ot al magnet ic f ield regardless of it s posit ion w it hin t he slic e. Ort hogonal slic es are t hose in w hic h only t he x, y , or z gradient is used as t he slic e selec t ion gradient . Oblique slic es, t hose not in one of t he princ ipal direc t ions, are obt ained by apply ing more t han one phy sic al gradient w hen t he rf pulse is broadc ast . T he t ot al gradient amplit ude det ermines t he slic e t hic kness. When images are v iew ed on t he monit or or f ilm, t he slic e selec t ion direc t ion is alw ay s perpendic ular t o t he surf ac e, t hat is, hidden f rom t he v iew er (F ig. 2- 19).

F igure 2- 17 Slic e selec t ion proc ess. In t he presenc e of a gradient (G SS ), t he t ot al magnet ic f ield t hat a prot on experienc es and it s result ing resonant f requenc y depend on it s posit ion, ac c ording t o Eq. 4. T issue loc at ed at posit ion z i w ill absorb rf energy broadc ast w it h a c ent er f requenc y П‰ i. Eac h posit ion w ill hav e a unique resonant f requenc y . T he slic e t hic kness Оґ z is det ermined by t he amplit ude of G SS and by t he bandw idt h of t ransmit t ed f requenc ies ОґП‰.

In MRI, t he rf energy is applied as pulsed exc it at ion, w it h sev eral f eat ures c harac t erizing t he pulse. When a pulse is applied, t here w ill be a c ent er

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications115 f requenc y , durat ion, shape, phase, and amplit ude def ined. T he c ent er f requenc y of t he pulse is normally c hosen as t he resonant f requenc y f or t he part ic ular c ollec t ion of prot ons under observ at ion. T he durat ion and shape of t he pulse det ermine t he bandw idt h, or range, of f requenc ies on eit her side of t he c ent er f requenc y t hat is exc it ed by t he pulse. T he phase of t he pulse def ines t he ef f ec t iv e orient at ion of t he rf energy and det ermines t he axis of rot at ion f or t he net magnet izat ion under t he inf luenc e of t he pulse. T he pulse amplit ude det ermines t he amount of rot at ion t hat t he prot ons undergo (f lip angle). In addit ion, t he pulse amplit ude is relat ed t o t he amount of energy t hat t he prot ons absorb and t heref ore must dissipat e t hrough T 1 relaxat ion.

F igure 2- 18 F or a giv en range (bandw idt h) of f requenc ies inc luded in t he rf pulse, t he desired slic e t hic kness is det ermined by t he slic e selec t ion gradient amplit ude. T he user int erf ac e t y pic ally allow s v ariat ion of slic e t hic kness, w hic h is ac hiev ed by inc reasing or dec reasing t he slic e selec t ion gradient amplit ude, as appropriat e.

In general, rf pulses are subjec t t o t w o c ompet ing c rit eria: · Short - durat ion pulses require high peak pulse amplit udes t o ac hiev e t he same pulse area (f lip angle). Depending on t he part ic ular rf amplif ier and t ransmit t er c oil, t he maximum pow er t hat c an be broadc ast is limit ed.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications116 · F or most applic at ions, unif orm amplit ude and phase exc it at ion t hroughout t he t issue v olume are desired; t hat is, all t he prot ons w it hin t he slic e should be rot at ed t he same amount and in t he same direc t ion, produc ing a unif orm exc it at ion prof ile. T his is only possible w it h low f lip angles (less t han 30 degrees). High- amplit ude pulses, suc h as 90- degree or 180degree pulses, hav e exc it at ion prof iles t hat are signif ic ant ly nonrec t angular. Manuf ac t urers st riv e t o prov ide unif orm exc it at ion prof iles, subjec t t o c rit erion 1. How ev er, due t o t he f init e nat ure of t he rf pulse durat ion and amplif ier pow er, t he prof ile w ill not be rec t angular, but w ill hav e sloped sides. T his means t hat , f or c losely spac ed slic es, t here w ill be areas t hat rec eiv e ov erlapping exc it at ion, a problem know n as c rosst alk, bet w een slic es.

Readout or Frequency Encoding T he signal det ec t ion port ion of t he MRI measurement is know n as t he readout or f requenc y enc oding. T he readout proc ess dif f erent iat es MRI f rom MR spec t rosc opy , t he ot her t y pe of MR proc ess. In an imaging pulse sequenc e, t he MR signal is alw ay s det ec t ed in t he presenc e of a gradient know n as t he readout gradient G RO, w hic h produc es one of t he t w o v isual dimensions of t he image on t he f ilm. A t y pic al pulse sequenc e uses some f orm of exc it at ion, suc h as a 90- degree slic e selec t iv e pulse, t o exc it e a part ic ular region of t issue. F ollow ing exc it at ion, t he net magnet izat ion w it hin t he slic e is orient ed t ransv erse t o B 0 and w ill prec ess w it h f requenc y П‰ 0. T 2* proc esses induc e dephasing of t his t ransv erse magnet izat ion (see t he sec t ion t it led Relaxat ion). T his dephasing c an be part ially rev ersed t o f orm an ec ho by t he applic at ion of a 180- degree rf pulse, a gradient pulse, or bot h. As t he ec ho is f orming, t he readout gradient is applied perpendic ular t o t he slic e direc t ion. Under t he inf luenc e of t his new gradient f ield, t he prot ons begin t o P.42 prec ess at dif f erent f requenc ies depending on t heir posit ion w it hin it , in ac c ordanc e w it h Eq. 4. Eac h of t hese f requenc ies is superimposed int o t he ec ho. At t he desired t ime, t he ec ho signal is measured by t he rec eiv er c oil and digit ized f or lat er F ourier t ransf ormat ion. T he magnit ude of G RO (GRO) and t he f requenc y t hat is det ec t ed enable t he c orresponding posit ion of t he prot on t o be det ermined (F ig. 2- 20).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications117

F igure 2- 19 Images in st andard slic e direc t ions: sagit t al, c oronal, and t ransv erse or axial. F or t ransv erse images, t w o v iew direc t ions are possible: c ranial and c audal. Annot at ions are based on pat ient axes.

T w o user- def inable paramet ers det ermine t he magnit ude of GRO: t he f ield of v iew in t he readout direc t ion, F OV RO, and t he Ny quist f requenc y П‰ NQ f or t he image, of t en ref erred t o as t he rec eiv er bandw idt h (Eq. 3). GRO is c hosen so t hat prot ons loc at ed at t he edge of t he F OV RO prec ess at t he Ny quist f requenc y f or t he image (F ig. 2- 21). Smaller v alues of F OV RO are ac hiev ed by inc reasing GRO, keeping t he Ny quist f requenc y , and t hus t he t ot al f requenc y bandw idt h, c onst ant (F ig. 2- 22). T he spat ial resolut ion, expressed as t he v oxel size w it h unit s of mm/pixel, is direc t ly proport ional t o F OV RO and inv ersely proport ional t o t he number of readout sample point s in t he ac quisit ion mat rix, NRO.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications118

F igure 2- 20 Readout proc ess. F ollow ing exc it at ion, eac h prot on w it hin t he exc it ed v olume (slic e) prec esses at t he same f requenc y . During det ec t ion of t he ec ho, a gradient (G RO) is applied, c ausing v ariat ion in t he f requenc ies f or t he prot ons generat ing t he ec ho signal. T he f requenc y of prec ession П‰ i f or eac h prot on depends on it s posit ion xi ac c ording t o Eq. 4. F requenc ies measured f rom t he ec ho are mapped t o t he c orresponding posit ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications119

F igure 2- 21 In any image, one of t he v isualized direc t ions is t he readout direc t ion, and t he ot her is t he phase- enc oding direc t ion. A prot on loc at ed at t he edge of t he f ield of v iew in t he readout direc t ion (F OV RO) prec esses at t he Ny quist f requenc y (П‰ NQ) abov e or below t he t ransmit t er f requenc y П‰ TR . Changing t he F OV of t he image c hanges t he spat ial resolut ion (mm per

pixel) but not t he f requenc y resolut ion (Hz per pixel).

P.43

Phase Encoding T he t hird direc t ion in an MR image is t he phase- enc oding direc t ion. It is v isualized along w it h t he readout direc t ion in an image (see F ig. 2- 21). T he phase- enc oding gradient , GPE, is perpendic ular t o bot h GSS and GRO and is t he only gradient t hat c hanges amplit ude during t he dat a ac quisit ion loop of a st andard t w o- dimensional (2D) imaging sequenc e. Any signal amplit ude v ariat ion det ec t ed f rom one ac quisit ion t o t he next is assumed t o be c aused by t he inf luenc e of GPE during t he measurement .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications120

F igure 2- 22 F or a giv en range (bandw idt h) of f requenc ies t hat are measured in t he signal, t he desired f ield of v iew (F OV) is det ermined by t he readout gradient amplit ude. T he user int erf ac e t y pic ally allow s v ariat ion of t he F OV, w hic h is ac hiev ed by inc reasing or dec reasing t he readout gradient amplit ude, as appropriat e.

T he princ iple of phase enc oding is based on t he f ac t t hat t he prot on prec ession is periodic in nat ure. Prior t o t he applic at ion of GPE, a prot on w it hin a slic e prec esses at t he base f requenc y П‰ 0. In t he presenc e of GPE, it s prec essional f requenc y inc reases or dec reases ac c ording t o Eq. 4. Onc e GPE is t urned of f , t he prot on prec ession ret urns t o it s original f requenc y , but is ahead or behind in phase relat iv e t o it s prev ious st at e. T he amount of induc ed phase shif t depends on t he magnit ude and durat ion of GPE t hat t he prot on experienc ed and t he prot on loc at ion. Prot ons loc at ed at dif f erent posit ions in t he phase- enc oding direc t ion experienc e dif f erent amount s of phase shif t f or t he same GPE pulse (F ig. 2- 23). A prot on loc at ed at t he edge of t he c hosen F OV experienc es t he maximum amount of phase shif t f rom eac h phaseenc oding st ep. T he MR image inf ormat ion is obt ained by repeat ing t he slic e exc it at ion and signal det ec t ion mult iple t imes, eac h w it h a dif f erent amplit ude of GPE. T he sec ond F ourier t ransf ormat ion in t he image c onv ert s t he signal amplit ude at eac h readout f requenc y f rom a f unc t ion of GPE t o a f unc t ion of phase.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications121 T he spat ial resolut ion in t he phase- enc oding direc t ion depends on t w o userselec t able paramet ers, t he f ield of v iew in t he phase- enc oding direc t ion, F OV PE, and t he number of phase- enc oding st eps in t he ac quisit ion mat rix, NPE. T he F OV PE is det ermined by t he c hange in GPEf rom one st ep t o t he next . F or a prot on loc at ed at t he c hosen F OV PE, eac h phase- enc oding st ep induc es one half c y c le (180 degrees) of phase c hange relat iv e t o t he prev ious phaseenc oding st ep, assuming a c onst ant pulse durat ion (F ig. 2- 24). NPE det ermines t he t ot al number of c y c les of P.44 phase c hange (NPE/2) produc ed at t he edge of t he F OV and t hus t he maximum f requenc y (П‰ NQ) in t he phase- enc oding direc t ion f or t he giv en pulse durat ion. T he spat ial resolut ion in t he phase- enc oding direc t ion is expressed as t he v oxel size and is measured in mm/pixel. Inc reased resolut ion is obt ained by reduc ing t he F OV PE or by inc reasing NPE. T he F OV reduc t ion is ac c omplished by inc reasing t he gradient amplit ude c hange f rom one GPE t o t he next .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications122 F igure 2- 23 Conc ept of phase enc oding. Prior t o applic at ion of G PE, all prot ons prec ess at t he same f requenc y . When G PE is applied, a prot on inc reases or dec reases it s prec essional f requenc y , depending on it s posit ion y i. A prot on loc at ed at y i=0 (y 2) experienc es no ef f ec t f rom G PE and no c hange in f requenc y or phase (П† 2 = 0). A prot on loc at ed at y 1 prec esses f ast er w hile G PE is applied. Onc e G PE is t urned of f , t he prot on prec esses at it s original f requenc y but is ahead of t he ref erenc e f requenc y (dashed c ur v e); t hat is, a phase shif t П† 1 has been induc ed t o t he prot on by G PE. A prot on loc at ed at y 3 dec reases it s f requenc y w hile G PE is applied. Onc e G PE is t urned of f , it prec esses at it s original f requenc y but is behind t he ref erenc e by a phase shif t of П† 3.

F igure 2- 24 Phase- enc oding proc ess. A prot on at t he edge of t he f ield of v iew in t he phase- enc oding direc t ion (F OV PE) undergoes 90 degrees of phase c hange ОґП† f rom one phase- enc oding st ep t o t he next . Eac h point w it hin t he F OV undergoes progressiv ely less phase c hange f or t he same gradient amplit ude. A prot on at t he isoc ent er nev er experienc es any phase c hange. T he c hange in gradient amplit ude (0.02 mT /m in t his example) f rom one phase- enc oding st ep t o t he next depends on t he part ic ular F OV c hosen.

Bec ause of t he t w o dif f erent phy sic al proc esses inv olv ed, F OV PE is not required t o be t he same as F OV RO, nor is t he v oxel size. T he rat io of v oxel sizes is know n as t he aspec t rat io bet w een t he t w o dimensions. An aspec t rat io of 1.0 (100%) means t hat t he v oxel size is t he same in bot h direc t ions, a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2 - Magnetic Resonance Imaging Principles and Applications123 c ondit ion ref erred t o as isot ropic resolut ion. An aspec t rat io less t han 1.0 ( T able of Cont ent s > 7 - Lung

7 Lung Stua rt S. Sa ge l

LARGE AIRWAYS Trachea Wit h t he adv ent of mult idet ec t or row sc anners, c omput ed t omography (CT ) has bec ome t he major imaging t ec hnique f or ev aluat ion of t he t rac hea and major bronc hi (189,318,386,414,665). Alt hough most disease proc esses inv olv ing t hese st ruc t ures are init ially det ec t ed on plain c hest radiography or endosc opy , CT is ext remely v aluable in det ermining t he ext ent of disease and in dif f erent ial diagnosis. CT is f ar superior t o endosc opy in ev aluat ing perit rac heobronc hial spread of disease and ext raluminal pat hology . Unlike single- det ec t or CT , mult idet ec t or- row CT (MDCT ) allow s 1- mm t ransaxial slic e t hic kness of t he ent ire t rac heobronc hial t ree and prov ides superb qualit y t w o- dimensional (2D) and t hree- dimensional (3D) ref ormat ions of t he c ent ral airw ay s, inc luding mult iplanar (c oronal/sagit t al), minimumint ensit y projec t ions (MinIPs), 3D shaded- surf ac e display s, and v olumerendered images (491). Int ernal rendering of t he t rac heobronc hial w all and lumen c an be obt ained using so c alled v ir t ual br onc hosc opy t ec hniques (213,482). Alt hough t he use of int rav enous c ont rast enhanc ement is not nec essary f or ev aluat ion of t he c ent ral airw ay s per se, it is of t en v aluable in helping depic t ext raluminal pat hology .

Tracheal Diseases

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

947

7 - Lung Diseases of t he t rac hea are not ed in T able 7- 1. T he most c ommon f oc al disease of t he t rac hea is a benign st ric t ure (F ig. 7- 1), usually t he result of prior int ubat ion or t rac heost omy . T rac heal neoplasms are relat iv ely unc ommon, w it h 90% being malignant (338). T he t w o major t y pes of t rac heal c arc inomas are squamous c ell (55%) and adenoc y st ic (18%). T he lat t er hav e a more insidious c linic al onset relat ed t o a slow er grow t h pat t ern. Hemat ogenous met ast ases t o t he t rac heal muc osa, suc h as f rom melanoma or breast c arc inoma, are rare. Malignant t rac heal neoplasms usually appear on CT as an ec c ent ric irregular sof t t issue mass w it hin t he lumen, most t y pic ally arising f rom t he post erior and lat eral w all (F ig. 7- 2). CT is v ery v aluable in assessing t heir possible resec t abilit y , by def ining ext ent of t umor, possible direc t inv asion of c ont iguous mediast inal st ruc t ures suc h as t he esophagus and aort a, and any assoc iat ed mediast inal ly mph node met ast ases. Benign t rac heal t umors inc lude squamous papilloma (almost alw ay s oc c urring init ially in y oung c hildren), pleomorphic adenoma, mesenc hy mal hamart oma, and t hose of c art ilaginous origin. T hese benign neoplasms t end t o be w ell c irc umsc ribed, smoot hly marginat ed, and less t han 2 c m in diamet er. In t rac heobronc homegaly (F ig. 7- 3) or t he Mounier- Kuhn sy ndrome (F ig. 7- 4), t here is dif f use dilat at ion of t he t rac hea (great er t han 3 c m) and c ent ral bronc hi, w it h t he f ormat ion of div ert ic ula in t he w all, as t he result of at rophy of t he c art ilage, musc les, and elast ic t issues of t he c ent ral airw ay s (359). Relapsing poly c hondrit is may manif est as dif f use smoot h narrow ing of t he t rac hea and c ent ral bronc hi (F ig. 7- 5). T rac heobronc hopat hia ost eoc hondroplast ic a (F ig. 7- 6), amy loidosis, sarc oidosis, and Wegener granulomat osis (F ig. 7- 7) t y pic ally appear as irregular narrow ing of t he t rac heobronc hial lumens. T rac heobronc hopat hia ost eoc hondroplast ic a is c harac t erized by t he presenc e of small 2- t o 5- mm ost eoc art ilaginous nodules w it hin t he submuc osa of t he t rac hea and c ent ral bronc hi. CT show s t hese small, c alc if ied int raluminal masses arising f rom t he ant erior and lat eral w alls, sparing t he post erior membranous t rac hea. TABLE 7- 1 DISEASES OF THE TRAC HEA

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

948

7 - Lung F oc a l St ric t ure Malignant neoplasm Benign neoplasm Diffuse Inc reased diamet er T rac heobronc homegaly Dec reased diamet er Relapsing poly c hondrit is T rac heobronc hopat hia ost eoc hondroplast ic a Amy loidosis Sarc oidosis Wegener's granulomat osis

F igure 7- 1 Post - int ubat ion t rac heal st enosis. A: Coronal and B: sagit t al v olume- rendered rec onst ruc t ions demonst rat e a 3- c m area of narrow ing in t he t rac hea abov e t he t horac ic inlet .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

949

7 - Lung

F igure 7- 2 Squamous c ell c arc inoma of t rac hea. A: T ransaxial c omput ed t omography demonst rat es a lef t - sided sof t t issue mass narrow ing t he t rac hea and ext ending int o t he adjac ent mediast inal f at . B: Coronal ref ormat ion demonst rat es t he lengt h of t he lef t t rac heal mass (ar r ow s), it s relat ionship t o nearby st ruc t ures, and t he inv asion int o t he lef t mediast inal f at .

F igure 7- 3 T rac heobronc homegaly assoc iat ed w it h adv anc ed int ersit ial pulmonary f ibrosis. A, B: Selec t ed c ephaloc audal c omput ed t omography images demonst rat e t rac heal and main bronc hial dilat at ion, plus ext ensiv e honey c ombing and peripheral f ibrosis. A small pneumomediast inum is present .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

950

7 - Lung

F igure 7- 4 Mounier- Kuhn sy ndrome. A, B: Selec t ed c ephaloc audal t ransaxial c omput ed t omography images demonst rat e dilat at ion of t he t rac hea and main bronc hi, w it h some luminal c ont our irregularit ies. Parasept al emphy sema and c y st ic bronc hiec t asis also are present . C : Coronal minimum- int ensit y projec t ion rec onst ruc t ion bet t er depic t s t he marginal irregularit ies of t he t rac hea and main bronc hi (ar r ow s). (D) T ransaxial c omput ed t omography in anot her pat ient demonst rat es marked bronc hial luminal irregularit ies.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

951

7 - Lung

F igure 7- 5 Relapsing poly c hondrit is. A, B: Selec t ed c ephaloc audal c omput ed t omography images in inspirat ion show relat iv ely normal c ent ral airw ay s. C , D: Images at same lev els in expirat ion demonst rat e t rac heobronc homalac ia w it h not able narrow ing of t he airw ay s.

P.422 P.423 P.424

Bronchi As st at ed prev iously , CT is a sensit iv e t ec hnique f or depic t ing anat omic dist ort ions (dilat at ion, t hic kening, narrow ing) (F ig. 7- 8) inv olv ing t he major bronc hi. Approximat ely 95% of endobronc hial lesions t hat are ident if ied by f iberopt ic bronc hosc opy c an be det ec t ed by CT , inc luding v irt ually all primary neoplasms (F ig. 7- 9), espec ially w hen t hinly c ollimat ed images are obt ained in t he area of int erest (229,413,415,416,421,422) (F ig. 7- 10). Assoc iat ed c hanges in t he dist al pulmonary parenc hy ma suc h as c ollapse (F igs. 7- 11 and 7- 12), c onsolidat ion (F ig. 7- 13) and, rarely , f oc al ov erdist ension (see F ig. 710B) may be demonst rat ed.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

952

7 - Lung Proper assessment of airw ay morphology nec essit at es t hat t he CT slic e t hic kness c hosen be no larger, and pref erably t hinner, t han t he diamet er of t he airw ay being ev aluat ed (191). Mult iplanar or 3D rec onst ruc t ions may be adv ant ageous in selec t ed c ases, part ic ularly if surgery is planned, espec ially t o assess t he lengt h of st enosis in obliquely orient ed airw ay s (102,267,319). Crit ic al inf ormat ion may be more easily c onv ey ed t o t he surgeon in t hese planes, ev en t hough somet imes no real addit ional diagnost ic inf ormat ion is prov ided. Int ernally rendered images of t he airw ay lumen also may be c onst ruc t ed, so- c alled v ir t ual br onc hosc opy , w hic h simulat e t he perspec t iv e P.425 P.426 P.427 P.428 of t he bronc hosc opist (622). How ev er, w it h suc h met hodology art if ac t s are somet imes induc ed t hat simulat e pat hology , and no inf ormat ion about t he bronc hial muc osa or hist ology of a lesion is prov ided.

F igure 7- 6 T rac heobronc hopat hia ost eoc hondroplast ic a. A: Coronal rec onst ruc t ion demonst rat es irregular c alc if ied luminal narrow ings in t he t rac hea and major bronc hi. B: Volume- rendered c oronal rec onst ruc t ion depic t s t he nodular luminal irregularit ies (ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

953

7 - Lung

F igure 7- 7 Wegener granulomat osis. A: T ransaxial c omput ed t omography demonst rat es marked t rac heal narrow ing. B: Coronal minimum- int ensit y projec t ion rec onst ruc t ion show s irregular luminal narrow ings t hroughout t he t rac heobronc hial t ree.

F igure 7- 8 Comput ed t omography show s marked narrow ing of t he bronc hus int ermedius (ar r ow ) due t o bronc homalac ia.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

954

7 - Lung

F igure 7- 9 Squamous c ell c arc inoma. A: In a pat ient w it h a v ague right parat rac heal opac it y not ed on plain c hest radiograph, c omput ed t omography demonst rat es a mass narrow ing t he apic al segment al bronc hus (ar r ow ) of t he right upper lobe. B: A more c audal image show s t he neoplasm ext ending int o t he proximal right main st em bronc hus (ar r ow ).

F igure 7- 10 Endobronc hial lesion. A: c omput ed t omography demonst rat es a poly poid mass (ar r ow ) in t he bronc hus int ermedius. B: Sc an at slight ly more c ephalad lev el obt ained in expirat ion demonst rat es marked air t rapping in t he right low er lobe. An aspirat ed piec e of c aulif low er w as f ound at bronc hosc opy and remov ed.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

955

7 - Lung

F igure 7- 11 Bronc hial obst ruc t ion. A: Dilat ed muc us- f illed bronc hi (ar r ow s) are seen in lat eral segment of t he middle lobe on t his post c ont rast c omput ed t omography image. A round high- at t enuat ion lesion c ent rally simulat es a small pulmonary art ery . B: Same image, w it h higher w indow lev el and w ider w indow set t ings demonst rat es a small bronc holit h (ar r ow ) oc c luding t he lat eral segment bronc hus.

F igure 7- 12 Bronc hial obst ruc t ion. A, B: Sequent ial c omput ed t omography images demonst rat e muc us f illing and obst ruc t ing t he bronc hus int ermedius (ar r ow s), w it h dist al bronc hial muc us- plugging (ar r ow heads) and at elec t asis, in t his post operat iv e pat ient originally suspec t ed t o hav e pulmonary embolism.

Due t o it s bet t er spat ial resolut ion, CT is superior t o magnet ic resonanc e imaging (MRI) in demonst rat ing bot h normal bronc hi and endobronc hial masses (366). CT may be helpf ul in t he selec t ion of pat ient s f or bronc hosc opy or an alt ernat iv e diagnost ic t est (38,136). It c an be used w hen t he c linic al suspic ion of endobronc hial disease is low t o improv e t he pot ent ial diagnost ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

956

7 - Lung y ield of bronc hosc opy ; t hat t ec hnique may be obv iat ed if CT show s no bronc hial abnormalit y . Predic t ing w het her an abnormalit y seen on CT is endobronc hial, submuc osal, or ext rinsic (peribronc hial) is f raught w it h error, and CT is not as ac c urat e as bronc hosc opy in det ec t ing submuc osal spread of neoplasm. When t ransbronc hial needle aspirat ion biopsy is c ont emplat ed, CT may be of major assist anc e in dec iding w het her it is w arrant ed and also in guiding it s applic at ion bec ause it prov ides a det ailed assessment of any assoc iat ed mediast inal ly mph node mass and it s relat ionship t o t he adjac ent major airw ay s P.429 and v essels (521). Somet imes a benign et iology f or a suspec t ed lesion, suc h as bronc holit hiasis (302) (see F igs. 7- 11 and 7- 13), is demonst rat ed. On CT , c alc if ic at ion t hat is eit her endobronc hial or peribronc hial usually is v isible, and t he inv olv ed bronc hus may be narrow ed or c omplet ely obst ruc t ed. T here may be dist al lung at elec t asis, c onsolidat ion, bronc hiec t asis, or rarely , airt rapping. Ec t opic bronc hi, inc luding an ac c essory c ardiac bronc hus or a t rac heal bronc hus, w hic h may predispose t o rec urrent lung inf ec t ions, c an be rec ognized on CT . In a pat ient w it h c ongenit al bronc hial at resia, CT may depic t c onc omit ant regional lung hy podensit y bey ond a dilat ed muc us- f illed bronc hus more c onv inc ingly t han c onv ent ional c hest roent genography (F ig. 714).

F igure 7- 13 Post obst ruc t iv e inf lammat ion. A bronc holit h (ar r ow ) obst ruc t s superior segment of t he lef t low er lobe, w it h dist al inf ilt rat e and at elec t asis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

957

7 - Lung

F igure 7- 14 Bronc hial at resia. A: Vague nodular opac it y seen in t he post erior basal segment of t he right low er lef t lobe on an abdominal c omput ed t omography st udy . B: On c oronal ref ormat t ed c hest c omput ed t omography image, hy perinf lat ed lung is depic t ed surrounding t he muc us plugged bronc hus (ar r ow ). C : In anot her pat ient , c omput ed t omography demonst rat es muc us f illing medial basal bronc hus of t he right low er lobe (ar r ow ), w it h dec reased v asc ularit y and hy perinf lat ion of t his segment .

“Bronchial Adenoma” Comprising a group of neoplasms t hat generally arise w it hin t he proximal bronc hi or t rac hea, t he t erm br onc hial adenom a is an ac know ledged misnomer bec ause t hese lesions are neit her benign nor usually glandular. All of t he v arious hist ologic t y pes—inc luding c arc inoid (75%), c y lindroma, adenoc y st ic , and muc oepidermoid—should be c onsidered low - grade c arc inomas (612).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

958

7 - Lung T hese malignant neoplasms usually grow slow ly but may met ast asize t o t he mediast inal ly mph nodes or ext rat horac ic sit es. T he primary lesion may grow predominant ly int raluminally or, alt ernat iv ely , may hav e a small int raluminal c omponent w hile ext ending deep int o t he adjac ent peribronc hial (pulmonary parenc hy ma or mediast inum) or parat rac heal P.430 sof t t issues (F ig. 7- 15). If t he lesion is mainly int raluminal, t he bronc hus may bec ome oc c luded (F ig. 7- 16). Alt hough dist al air t rapping may oc c ur, most c ommonly at elec t asis or obst ruc t iv e pneumonit is in t he subt ended lung result s, w hic h may be lobar or segment al, depending on t he loc at ion and size of t he lesion.

F igure 7- 15 Bronc hial c arc inoid. A: Post c ont rast c omput ed t omography demonst rat es a relat iv ely large, mainly ext raluminal, hy perv asc ular mass (ar r ow heads) arising f rom t he bronc hus int ermedius. B: Posit ron emission t omography imaging demonst rat es no inc reased upt ake, and t he mass w as int erpret ed as a hamart oma or granuloma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

959

7 - Lung

F igure 7- 16 Bronc hial c arc inoid. A, B: Post c ont rast selec t ed c ephaloc audal c omput ed t omography images demonst rat e a large hy perv asc ular mass (c ur v ed ar r ow s) oc c luding most of t he bronc hus int ermedius and t he ent ire right low er lobe bronc hus. C : Coronal rec onst ruc t ion show s t he mass in t he bronc hus int ermedius (ar r ow ), w it h some muc us plugging of small right low er lobe bronc hi (ar r ow heads).

Pulmonary c arc inoids arise f rom neurosec ret ory c ells in t he c onduc t ing airw ay , and c omprise about 2% of lung neoplasms (522). T hese neuroendoc rine c ells c an giv e rise t o a spec t rum of c arc inomas, ranging f rom w ell dif f erent iat ed (so c alled t y pic al c ar c inoid) t o moderat ely dif f erent iat ed (prev iously t ermed at y pic al c ar c inoid) t o t he ext remely aggressiv e small c ell undif f erent iat ed c arc inoma of t he lung. T he w ell dif f erent iat ed neuroendoc rine c arc inomas (80%) arise in t he c ent ral airw ay , most t y pic ally t he right upper and middle lobe bronc hi, oc c ur usually bet w een t he ages of 35 t o 50 y ears, and hav e a f requenc y of met ast asis of about 5%. T he moderat ely dif f erent iat ed neuroendoc rine c arc inomas (or at y pic al c arc inoids), are seen in somew hat older pat ient s, t end t o oc c ur more peripherally bey ond t he segment ed bronc hi,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

960

7 - Lung and met ast asize in about 70% of pat ient s. Bec ause of t heir loc at ion and relat iv ely indolent grow t h, c ent ral c arc inoids f requent ly present as hemopt y sis, c ough or rec urrent inf ec t ion. T he c arc inoid sy ndrome is rare (3%). CT c an be v ery helpf ul in t he preoperat iv e def init ion of t he t ot al ext ent of t hese inf ilt rat ing neoplasms, espec ially t he ext raluminal c omponent (23,419). When no ext ension out side t he bronc hial w all is seen, loc al sleev e resec t ion of t he t umor w it h repair of t he bronc hus may be f easible (F ig. 7- 17). T he w elldif f erent iat ed neuroendoc rine c arc inoma (t y pic al c arc inoid) generally is highly v asc ular and usually demonst rat es subst ant ial enhanc ement f ollow ing dy namic int rav enous c ont rast administ rat ion. It also may arise more peripherally in t he lung, almost alw ay s in c lose proximit y t o a bronc hus, and usually appears as a sharply marginat ed nodule f requent ly c ont aining some st ippled c alc if ic at ion (F ig. 7- 18).

Bronchogenic Carcinoma Bronc hogenic c arc inoma c urrent ly is t he leading c ause of c anc er deat h (27%) in bot h men and w omen older t han 35 y ears in t he indust rialized w orld. More indiv iduals die f rom t his neoplasm in t he Unit ed St at es t han f rom t he t hree next most c ommon c auses of c anc er deat h (breast , c olorec t al, and prost at e c arc inoma) c ombined. CT serv es a dual role in t he pat ient suspec t ed t o hav e a bronc hogenic c arc inoma based on t he plain c hest radiograph. Init ially , it may subst ant ially f ac ilit at e t he diagnost ic ev aluat ion, by prov iding more prec ise c harac t erizat ion of t he size, c ont our, ext ent , and t issue c omposit ion of t he suspic ious lesion (7,31,316,317). In addit ion, if t he lesion likely represent s a lung c arc inoma, CT c an not ably inf luenc e t he t herapeut ic plan as it serv es as part of t he st aging proc ess t o assess t he ext ent of t he disease (53,325). Commonly , CT is f irst perf ormed t o c onf irm or f urt her assess an abnormalit y seen on t he c hest radiography . Suc h a CT examinat ion, in approximat ely 20% of pat ient s ref erred t o a t ert iary c are c ent er, w ill demonst rat e t hat t he P.431 P.432 P.433 quest ioned abnormal opac it y represent s an inc onsequent ial or benign lesion (467) (F igs. 7- 19, 7- 20, 7- 21, 7- 22). A benign et iology (e.g., granuloma, hamart oma, art eriov enous malf ormat ion, bronc holit hiasis) may be c onf ident ly dist inguished f rom a suspec t ed primary malignant neoplasm, and eit her f urt her

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

961

7 - Lung w orkup obv iat ed or dif f erent inv est igat ion and/or management direc t ed (F ig. 7- 23).

F igure 7- 17 Bronc hial c arc inoid. A: Post c ont rast t ransaxial c omput ed t omography show s a hy perv asc ular mass (ar r ow s) in t he right main st em bronc hus at t he lev el of t he right upper lobe bronc hus (ar r ow head). B: Coronal ref ormat t ed c omput ed t omography demonst rat es a mainly int raluminal mass (ar r ow ). Af t er v iew ing t his image, t he t horac ic surgeon perf ormed a suc c essf ul c onserv at iv e “ plast ic sleev e” resec t ion of t he mass, rat her t han a c ont emplat ed pneumonec t omy based upon his bronc hosc opic observ at ions.

F igure 7- 18 Calc if ied bronc hial c arc inoids. A: Comput ed t omography show s a mainly ext raluminal mass arising f rom apic al bronc hus (ar r ow ) of t he right upper lobe. B: In anot her pat ient , c omput ed t omography demonst rat es a large mainly ext raluminal mass arising f rom t he right low er lobe bronc hus (ar r ow ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

962

7 - Lung

F igure 7- 19 Benign pulmonary lesion. A: Post eroant erior c hest radiograph demonst rat es a v ague nodular opac it y (ar r ow ) projec t ing ov er t he lef t mid lung zone. B: Nonc ont rast c omput ed t omography show s a dif f usely c alc if ied, w ell- c irc umsc ribed pulmonary nodule (ar r ow ), c ompat ible w it h an old healed granuloma.

T he f indings on t he CT examinat ion c an be v aluable in direc t ing f urt her ev aluat ion and est ablishing a def init iv e pat hologic diagnosis w hen t he lesion in quest ion probably represent s a bronc hogenic c arc inoma (17,280,325,326,362). T he likelihood of a posit iv e diagnosis f rom bronc hosc opy c an be predic t ed if a bronc hus is seen leading t o or c ont ained w it hin t he pulmonary lesion (146,423) (F ig. 7- 24). Bec ause CT prov ides a det ailed depic t ion of t he segment al and usually t he subsegment al bronc hi, det erminat ion of t he loc at ion of an endobronc hial mass may be a helpf ul adjunc t in direc t ing t he bronc hosc opist t o t he appropriat e biopsy sit e. An alt ernat iv e appropriat e diagnost ic and/or st aging t est may be suggest ed, be it a t ransc erv ic al mediast inosc opy (F igs. 725 and 7- 26), ant erior parast ernal mediast inot omy (F igs. 7- 27 and 7- 28), perc ut aneous or t ransbronc hosc opic needle biopsy (F igs. 7- 29 and 7- 30), and somet imes direc t t horac ot omy if t he lesion is almost c ert ainly neoplast ic and no addit ional abnormalit ies are disc erned (F igs. 7- 31 and 7- 32). CT c an be

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

963

7 - Lung helpf ul in planning and guiding perc ut aneous needle biopsy (131), alt hough of t en larger peripheral lesions c an be biopsied under f luorosc opic or ult rasound guidanc e. Small subpleural blebs may be seen on CT t hat w ere not apparent on plain c hest radiographs, prompt ing a rev ision in t he direc t ion of t he biopsy needle t o reduc e t he risk of produc ing a pneumot horax. Bec ause t he ov erall ac c urac y of CT and MRI are quit e similar, and bec ause CT is more readily av ailable, less c ost ly , and quic ker t o perf orm, it usually is t he init ial c ross- sec t ional t omographic proc edure c hosen. In selec t ed c ases, MRI c an play a c omplement ary role. A f oc used MRI examinat ion may be used t o resolv e a spec if ic quest ion relat ed t o inv asion of t he mediast inum or c hest w all, or in f urt her c harac t erizat ion of an adrenal mass. MRI should be c onsidered an alt ernat iv e primary t omographic t ec hnique in a pat ient w it h a c ent ral mass in w hom iodinat ed int rav enous c ont rast media c annot be administ ered and possibly w it h suspec t ed superior sulc us t umor.

F igure 7- 20 Benign pulmonary lesion. Comput ed t omography demonst rat es bot h f at and c alc if ic at ion w it hin a w ell- c irc umsc ribed 1- c m right upper lobe nodule, t y pic al of a hamart oma.

T here are at least a dozen dif f erent t y pes of lung c anc er (523). More t han 95% arise f rom t he bronc hial or bronc hiolar epit helium or f rom bronc hial muc us glands; t hese c arc inomas may be of t he squamous c ell (epidermoid), adenoc arc inomas, or large or small c ell undif f erent iat ed t y pe. F or pragmat ic reasons, bronc hogenic c arc inoma is of t en div ided int o t w o broad hist ologic c at egories: non–small c ell and small c ell. Despit e signif ic ant adv anc es in c hemot herapy and radiat ion t herapy , c ure of non–small c ell bronc hogenic c arc inoma (approximat ely 85% of t hese c arc inomas) basic ally is ac hiev able only by surgic al resec t ion, and t hen only in c ert ain c at egories of limit ed

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

964

7 - Lung disease. Small c ell c arc inomas are rarely amenable t o surgic al t reat ment bec ause of t heir aggressiv e behav ior and usual w idespread inv olv ement at t he t ime of present at ion. A f ew of t hese pat ient s w it h limit ed disease at present at ion or w hen a preoperat iv e hist ologic diagnosis w asn't est ablished w ill hav e surgic al resec t ion, but post operat iv e c hemot herapy generally is used as mic romet ast ases are suspec t ed t o be present in most pat ient s. Ult imat ely , only about 40% of pat ient s w it h new ly diagnosed bronc hogenic c arc inoma are amenable t o surgic al resec t ion w it h c urat iv e int ent . Ac c urat e preoperat iv e st aging is ext remely desirable f or dif f erent iat ing t hose pat ient s w it h loc alized disease suit able f or c urat iv e surgery f rom t hose w it h more w idespread neoplasm bet t er managed w it h palliat iv e t herapy . Surgery should be rest ric t ed f or c omplet e t umor resec t ion; inc omplet e palliat iv e resec t ion in pat ient s w it h adv anc ed disease should be av oided. A resec t able t umor is def ined simply as t ec hnic ally one t hat c an be c omplet ely remov ed by surgery . Operabilit y t akes int o c onsiderat ion w het her surgery is appropriat e t herapy c onsidering t he pat ient 's ov erall medic al c ondit ion, as w ell as t he presumpt iv e prognosis and operat iv e morbidit y and mort alit y rat e relat ed t o t he size, loc at ion, and hist ology of t he primary lesion.

Staging T reat ment of bronc hogenic c arc inoma, as just desc ribed, is dependent not only on t he pat ient 's ov erall medic al st at us and t he hist ology of t he t umor, but also on t he st age of t he disease. T he purpose of any st aging sy st em is t o prov ide c onsist enc y in c ommunic at ion about t he ext ent of disease t o help det ermine prognosis, t hus serv ing as a basis f or selec t ion of t he most appropriat e t herapeut ic opt ion. Ac c urat e preoperat iv e st aging of a new lung c anc er is essent ial t o selec t t hose pat ient s w it h loc alized disease f or c urat iv e surgery P.434 P.435 P.436 P.437 P.438 P.439 P.440 P.441 P.442

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

965

7 - Lung and t hose w it h w idespread neoplasm f or palliat iv e t herapy , and is a c ombined responsibilit y of t he radiologist , pulmonologist , t horac ic surgeon, and t he pat hologist , based on c linic al (phy sic al) f indings, in c onjunc t ion w it h radiologic and laborat ory assessment , and supplement ed by pat hologic sampling (e.g., bronc hosc opy , mediast inosc opy , needle biopsy , v ideosc opic assist ed t horac ic surgery ). T he t umor, node, met ast ases (T NM) sy st em (T able 7- 2), w hic h relat es t o bot h resec t abilit y and operabilit y , is most c ommonly used f or lung neoplasms, in w hic h T desc ribes t he f eat ures of t he primary t umor, N ref ers t o t he presenc e or absenc e of regional ly mph node inv olv ement , and M ref ers t o t he st at us of ext rat horac ic met ast ases. Ly mph node st at us (N) is a bet t er predic t or of long- t erm result s t han t he size of t he primary t umor (T ). T he N c at egory prec isely ident if ies anat omic regions of mediast inal nodal inv olv ement based on def ined nodal st at ions (see F ig. 5- 56 and T able 5- 1 in Chapt er 5).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

966

7 - Lung

F igure 7- 21 Benign t horac ic lesions. A: Post eroant erior c hest radiograph demonst rat es a nodular opac it y projec t ing ov er t he lef t mid lung. B: Comput ed t omography demonst rat es a presumpt iv e ost eoc hondroma of t he rib (ar r ow s) ac c ount ing f or t he opac it y . T he lesion remained unc hanged on 4- y ear radiologic f ollow - up. C , D: In anot her pat ient , t ransaxial and v olume- rendered rec onst ruc t ion c omput ed t omography images w it h a bone w indow set t ing show a sc lerot ic f oc us, c ompat ible w it h a bone island, in a lef t post erior rib (ar r ow ), ac c ount ing f or a v ague nodular opac it y seen on a prev ious post eroant erior c hest radiograph.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

967

7 - Lung

F igure 7- 22 F ibrosis mimic king a superior sulc us c arc inoma. A: Post eroant erior c hest radiograph demonst rat es asy mmet ric opac if ic at ion of t he right lung apex. B, C : Sequent ial c ephaloc audal c omput ed t omography images demonst rat e predominant ly f at , w it h sev eral linear f ibrot ic st rands, in t he right apex, undoubt edly t he result of healed granulomat ous disease. No sof t t issue mass or bone dest ruc t ion in seen. (H) hemat oma in right pec t oralis major musc le f rom rec ent pac emaker plac ement ; (t h) right lobe of t hy roid; (b) right brac hioc ephalic v ein; (c ) right c arot id art ery ; (s) right subc lav ian art ery .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

968

7 - Lung

F igure 7- 23 Ost eosarc oma of rib. A: Post eroant erior c hest radiograph demonst rat es a 2.5- c m mass projec t ing ov er t he right midlung, init ially presumed t o represent a bronc hogenic c arc inoma. B: Comput ed t omography demonst rat es a markedly c alc if ied lesion in t he right f ourt h ant erior rib w it h spic ulat ed ext ension int o a surrounding sof t t issue at t enuat ion mass.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

969

7 - Lung

F igure 7- 24 Bronc hogenic c arc inoma. A: Comput ed t omography show s a 2- c m spic ulat ed mass arising f rom t he lingular bronc hus (ar r ow ). B: In anot her pat ient , c omput ed t omography demonst rat es a 1.5- c m spic ulat ed mass (ar r ow ) arising f rom an ant erior segment al bronc hus of t he lef t upper lobe. C , D: In anot her pat ient , sequent ial c omput ed t omography sc ans show an irregular 2- c m lobulat ed mass arising f rom post erior segment of t he right upper lobe bronc hus (ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

970

7 - Lung

F igure 7- 25 Bronc hogenic c arc inoma. A: Comput ed t omography show s a 2- c m irregular mass in post erior basal segment of t he lef t low er lobe. B: More c ephalad c omput ed t omography image show s an 11 Г— 14- mm enlarged c ont ralat eral pret rac heal ly mph node (ar r ow ), w hic h w as c onf irmed on mediast inosc opy t o c ont ain poorly dif f erent iat ed squamous c ell c arc inoma.

F igure 7- 26 Bronc hogenic c arc inoma. Comput ed t omography show s a mass (m) in t he lef t upper lobe, some enlarged ly mph nodes in t he aort opulmonary (a) and lef t hilar (l) areas, and an enlarged c ont ralat eral right pret rac heal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

971

7 - Lung ly mph node (ar r ow ). T he lat t er w as sampled by mediast inosc opy disc losing poorly dif f erent iat ed adenoc arc inoma.

F igure 7- 27 Bronc hogenic c arc inoma. A: Comput ed t omography demonst rat es c omplet e oc c lusion of t he lef t upper lobe bronc hus, w it h dist al c onsolidat ion and absc ess f ormat ion. A small peric ardial ef f usion (e) also is present . B: A more c ephalad c omput ed t omography image show s enlarged ly mph nodes in t he aort opulmonary w indow (ar r ow s). T hese w ere biopsied v ia an ant erior parast ernal mediast inot omy and c ont ained poorly dif f erent iat ed squamous c ell c arc inoma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

972

7 - Lung

F igure 7- 28 St age IV bronc hogenic c arc inoma. A: Comput ed t omography show s a lef t upper lobe mass (ar r ow ). B: On a more c ephalad image, enlarged ly mph nodes in t he aort opulmonary w indow (ar r ow heads) are demonst rat ed. Spec imens obt ained f rom lef t ant erior parast ernal mediast inot omy disc losed poorly dif f erent iat ed adenoc arc inoma. C Conc omit ant liv er met ast ases (ar r ow heads) seen on sc an t hrough upper abdomen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

973

7 - Lung

F igure 7- 29 Bronc hogenic c arc inoma. Comput ed t omography - guided biopsy (done in prone posit ion) of a c av it ary lef t low er lobe mass v erif ies needle t ip (ar r ow ) in w all of t he lesion. Spec imens disc losed squamous c ell c arc inoma.

F igure 7- 30 Bronc hogenic c arc inoma. A: Comput ed t omography demonst rat es an irregularly enhanc ing, part ially nec rot ic 2- c m right low er lobe mass

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

974

7 - Lung (ar r ow ). Calc if ied pleural plaques relat ed t o prior asbest os exposure are present . B: A more c ephalad c omput ed t omography image show s an enlarged nec rot ic right hilar ly mph node (ar r ow ). C : A c omput ed t omography image ev en more c ephalad show s a nec rot ic subc arinal ly mph node (ar r ow ), w hic h w as sampled v ia t ransbronc hosc opic needle aspirat ion disc losing large c ell undif f erent iat ed c arc inoma.

F igure 7- 31 Bronc hogenic c arc inomas. A: Det ail v iew f rom post eroant erior c hest radiograph demonst rat es an ill- def ined lef t upper lobe opac it y . B: Comput ed t omography demonst rat es a 2- c m lef t upper lobe mass w it h spic ulat ed irregular margins, c harac t erist ic of a primary bronc hogenic c arc inoma. Surgic al resec t ion disc losed adenoc arc inoma. C : In anot her pat ient , c omput ed t omography demonst rat es a 3- c m spic ulat ed lef t upper lobe

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

975

7 - Lung mass. Surgic al resec t ion disc losed small c ell undif f erent iat ed c arc inoma. Comput ed t omography and posit ron emission t omography imaging show ed a normal mediast inum, and surgic al nodal sampling w as negat iv e. TABLE 7- 2 TUMOR, NODE, METATASES (TNM) C ATEGORIES F OR LUNG C ANC ER Prima ry Tumor (T): T1

T2

T3

T4

Noda l Inv olv e me nt (N): N0 N1 N2 N3

3.0 c m or less in great est diamet er, surrounded by lung or v isc eral pleura, w it hout inv asion proximal t o a lobar bronc hus. More t han 3.0 c m in great est diamet er, or a t umor of any size t hat eit her inv ades t he v isc eral pleura or has assoc iat ed lobar at elec t asis or obst ruc t iv e pneumonit is. T he proximal ext ent of demonst rable t umor must be w it hin a lobar bronc hus or at least 2.0 c m dist al t o t he c arina. T umor of any size w it h direc t ext ension int o c hest w all, diaphragm, mediast inal pleura or peric ardium; a t umor t hat inv olv es a main bronc hus w it hin 2.0 c m of t he c arina (exc ept f or a superf ic ial lesion). T umor of any size w it h inv asion of great v essels, t rac hea or c arina, esophagus, heart , v ert ebral body or presenc e of a malignant pleural ef f usion (posit iv e c y t ology ). No inv olv ement of regional ly mph nodes. Met ast asis t o ly mph nodes in t he ipsilat eral peribronc hial or hilar region. Met ast asis t o ipsilat eral mediast inal or subc arinal ly mph nodes. Met ast asis t o suprac lav ic ular c ont ralat eral mediast inal/sc alene or ly mph nodes.

Dista nt Me ta sta sis (M): M0 No dist ant met ast asis. M1 Dist ant met ast asis present . T he c lassif ic at ion c onsist s of f our st ages (T able 7- 3). St ages I and II pat ient s

(about 25% at present at ion) hav e primary c arc inomas c onf ined w it hin t he pleura, w it h or w it hout hilar ly mph node inv olv ement ; t hey are usually surgic ally resec t able. St age IIIa disease is c lassif ied as operable. T he t ec hnic al prof ic ienc ies and approac hes of surgeons v ary and disparat e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

976

7 - Lung opinions may arise ov er t he def init ion of limit ed inv asion or nodal disease, and c onsequent ly , resec t abilit y . Pat ient s w it h st age IIIa disease hav e limit ed inv asion of t he mediast inum or c hest w all (T 3), and are c onsidered pot ent ially resec t able if v it al st ruc t ures in t he mediast inum are not inv olv ed. It also inc ludes pat ient s w it h limit ed ipsilat eral mediast inal nodal disease, w hic h somet imes may be surgic ally resec t ed f or c ure. Most av ailable dat a suggest t hat surgery improv es prognosis only w hen suc h met ast ases are rest ric t ed t o a single low mediast inal ly mph node st at ion and do not ext end t hrough t heir c apsule (no bulk nodal disease present ). Hist ology ot her t han w elldif f erent iat ed squamous c ell c arc inoma in mediast inal nodal met ast ases also equat es w it h poor surv iv al f ollow ing surgic al resec t ion. St age IIIb c arc inomas direc t ly inv ade t he v it al mediast inal st ruc t ures (T 4) (great v essels, heart , aerodigest iv e t rac t ), or are assoc iat ed w it h a malignant pleural ef f usion, or hav e spread t o c ont ralat eral or suprac lav ic ular ly mph nodes (N3); t hey are v irt ually alw ay s unresec t able f or c ure. Generally , bronc hogenic c arc inomas are c onsidered t o be unresec t able if t hey are c lassif ied as T 4, N3, or M1 (st age IV) (449). It is import ant t o reemphasize t hat dif f erent surgeons apply dif f erent c rit eria f or c onsidering a lesion resec t able, P.443 somet imes inf luenc ed by t he c linic al st at us and age of t he pat ient , espec ially in t he st age IIIa c at egory . TABLE 7- 3 STAGE GROUPING OF TUMOR, NODE, METATASES (TNM) C ATEGORIES F OR LUNG C ANC ER AND 5- Y EAR SURVIVAL Me ta sta se s 5- Y e a r Tumor(T) Node s (N) (M) Surv iv a l(% ) IA T1 N0 M0 61 IB T2 N0 M0 38 IIA T1 N1 M0 34 IIB* T2 N1 M0 24 T3 N0 M0 22 T 1 or T 2 N2 M0 13 IIIA T3 N1 or N2 M0 9 Any T N3 M0 7 IIIB T4 Any N M0 3 IV Any T Any N M1 1 * Panc oast t umors are IIB (T 3N0). Mult iple lesions same lobe T 4 dif f erent lobe M1 T he T NM sy st em is helpf ul in desc ribing t he anat omic ext ent of disease in an Sta ge

indiv idual pat ient and roughly c orrelat es w it h surv iv al, but it has sev eral

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

977

7 - Lung draw bac ks. T here is limit ed abilit y t o dist inguish bet w een primary lesions of disparat e size and loc at ion. No hist ologic dif f erent iat ion is inherent , and no dist inc t ion is made bet w een int rac apsular nodal met ast ases and ext rac apsular mat t ed nodes. Ly mph nodes st at us (N) is a bet t er predic t or of long- t erm result s t han t he size of t he primary t umor (T ) (453,464). T he surv iv al of pat ient s w it h non–small c ell c arc inoma c orrelat es relat iv ely w ell w it h t he anat omic ext ent or st age of t he disease, w hereas surv iv al in small c ell undif f erent iat ed c arc inoma generally does not c orrelat e (69,568,637). T hus small c ell c arc inoma is usually desc ribed as lim it ed (c onf ined t o t he ipsilat eral hemit horax and t he c ont ained ly mph nodes, w it hout a pleural ef f usion) or ext ensiv e (spread bey ond t hese areas). CT st aging of t he t horax and upper abdomen has a high ac c urac y in helping predic t t he likelihood of c urat iv e surgic al resec t ion (65,66,154,257). But it s role is not by it self t o det ermine operabilit y or est ablish prognosis. CT def ines gross anat omic abnormalit ies but has def init e hist ologic limit at ions and high spec if ic it y may not be possible. T he det ec t ion of an enlarged mediast inal ly mph node, or an enlarged adrenal gland or f oc al liv er lesion should not c onst it ut e suf f ic ient ev idenc e f or inoperabilit y bec ause suc h an abnormalit y may not be due t o met ast at ic neoplasm, ev en in a pat ient w it h a doc ument ed bronc hogenic c arc inoma. Hist ologic c orroborat ion of met ast at ic neoplasm w it hin t he enlarged node or abnormal organ is st rongly rec ommended in pat ient s ot herw ise c onsidered operat iv e c andidat es. Based on CT loc alizat ion of suspec t ed disease, t he appropriat e biopsy proc edure and ac c ess rout e c an be det ermined. CT should not be used t o replac e inv asiv e t ec hniques of st aging, suc h as t ransc erv ic al mediast inosc opy (see F igs. 7- 25 and 7- 26), ant erior parast ernal mediast inot omy (see F igs. 7- 27 and 7- 28), perc ut aneous needle biopsy (see F ig. 7- 29), or t ransbronc hosc opic needle aspirat ion biopsy (see F ig. 7- 30) (214,625), but t o opt imize more selec t iv e use of t hese t ec hniques. CT , perhaps in c onjunc t ion w it h posit ron emission t omography (PET ), may obv iat e inv asiv e st aging f or pat ient s w it h negat iv e f indings besides t he primary t umor. CT is c learly superior t o st andard radiologic t ec hniques f or demonst rat ing direc t ext ension of t he primary neoplasm int o t he mediast inum or c hest w all and det ec t ing enlarged mediast inal ly mph nodes, part ic ularly in t he pret rac heal, aort opulmonary , and subc arinal areas. In t hose pat ient s w it h c linic ally ev ident met ast at ic disease or unequiv oc al mediast inal ly mphadenopat hy on plain c hest radiography prec luding resec t ion, a CT st udy

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

978

7 - Lung is not required f or st aging purposes per se. Nev ert heless, CT may be v aluable f or biopsy planning or f or dev elopment of radiat ion t herapy port als, and t o assess t he result s of any subsequent c hemot herapy . T he anat omic inf ormat ion deriv ed f rom CT sc ans regarding t he ext ent of t he neoplast ic disease and it s relat ionship t o adjac ent st ruc t ures, as w ell as measurement s of surrounding t issue t hic kness, alt ers t he design of t he planned radiat ion dose dist ribut ion in approximat ely one t hird of pat ient s t o maximize t umor c ov erage and minimize irradiat ion t o uninv olv ed areas (117). Exte nt of the Prima ry Tumor (the T fa ctor). Cont iguous ext ension of a primary bronc hogenic c arc inoma int o t he mediast inum, part ic ularly w hen mediast inal v asc ular inv asion has oc c urred, generally prec ludes c urat iv e surgic al resec t ion. T he mediast inal st ruc t ures requiring c rit ic al assessment depend on t he sit e of t he primary t umor. Wit h right upper lobe (RUL) lesions, t he superior v ena c av a, right main bronc hus, and c arina need t o be c aref ully analy zed. Wit h lef t upper lobe (LUL) c arc inomas, spread c an oc c ur around t he aort ic arc h and int o t he aort opulmonary w indow , and t o t he main pulmonary art ery . Bot h middle lobe and lingular c anc ers c an direc t ly inv ade t he peric ardium and heart . Low er lobe lesions may inv olv e t he lef t at rium, inf erior pulmonary v ein, esophagus, or diaphragm; t hose on t he right side also c an ext end t o t he inf erior v ena c av a and lef t - sided t umors t o t he desc ending aort a. Wit h c onv ent ional t omography , it is generally impossible t o det ermine w het her a c ent rally sit uat ed pulmonary mass inv ades t he mediast inum or merely lies in c lose proximit y t o it . On CT , mediast inal inv asion should be absent if a preserv ed f at plane or port ion of t he lung is demonst rat ed bet w een t he primary neoplasm and t he mediast inal st ruc t ures (168,231,341). It should be emphasized t hat a neoplast ic mass simply c ont ac t ing t he mediast inal pleura, w it h t he lac k of a w ell- def ined f at plane bet w een t he lesion and t he mediast inum, does not indic at e mediast inal inv asion. A low probabilit y of inv asion exist s if t he t umor merely t ouc hes t he mediast inal f at ov er a v ery short dist anc e, w it h t he angle subt ended bet w een t he lesion and mediast inum less t han 90 degrees. T he sof t t issue at t enuat ion t umor mass must inf ilt rat e int o (int erdigit at e w it h) t he mediast inal f at and ext end around and of t ent imes subst ant ially dist ort t he great v essels or major bronc hi bef ore unresec t able ext ension c an be c onf ident ly diagnosed (F igs. 7- 33, 7- 34, 7- 35, 7- 36, 7- 37). Opt imal int rav enous c ont rast media administ rat ion is usually a requisit e t o c onf irm or exc lude mediast inal v asc ular enc asement . Limit ed inv asion of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

979

7 - Lung mediast inal pleura or peric ardium w it h sparing of v it al st ruc t ures (T 3) does not prec lude c urat iv e resec t ion. T umors demonst rat ing more ext ensiv e inv asion of t he mediast inum must also inv olv e c rit ic al st ruc t ures suc h as t he great v essels, t rac hea or c arina, esophagus, or heart t o be c lassif ied as unresec t able (T 4, or st age IIIb). A v it al role of t he radiologist is t o det ermine w het her a T 4 c lassif ic at ion is just if ied based on unequiv oc al CT (or MRI) f indings. A major c ont ribut ion of CT has been in est ablishing suc h adv anc ed bronc hogenic c arc inomas and P.444 P.445 P.446 exc luding t hese pat ient s f rom surgic al c onsiderat ion. How ev er, it is not alw ay s possible t o dist inguish T 3 f rom T 4 lesions; an indet erminat e c at egory w ould oc c ur w hen some oblit erat ion of t he mediast inal f at is present , or t he angle subt ended exc eeds 90 degrees, or w hen t he mediast inal v asc ular or airw ay dist ort ion is minimal (F ig. 7- 38). In most inst anc es, t hese pat ient s remain c andidat es f or surgic al resec t ion. Somet imes, c linic al experienc e must be int erjec t ed int o t he equat ion. Alt hough c ent ral t umors w it h pulmonary v enous ext ension t heoret ic ally are resec t able, t he prognosis in suc h c irc umst anc es is dismal and of t ent imes suc h a f inding c ont ribut es t o c onsidering a pat ient t o be inoperable alt hough t ec hnic ally not unresec t able (F ig. 7- 39).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

980

7 - Lung

F igure 7- 32 Bronc hogenic c arc inomas. A, B: Sequent ial c omput ed t omography images show a spic ulat ed right low er lobe adenoc arc inoma w it h assoc iat ed pleural t ags. C : In anot her pat ient , c omput ed t omography show s a spic ulat ed lef t upper lobe squamous c ell c arc inoma w it h desmoplast ic ret rac t ion of t he major f issure ant eriorly (ar r ow head).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

981

7 - Lung

F igure 7- 33 Unresec t able bronc hogenic c arc inoma. A: Comput ed t omography show s a large mass oc c luding t he right upper lobe bronc hus (blac k ar r ow ), direc t ly inv ading int o t he mediast inum, w it h ext ension t o t he prec arinal area (w hit e ar r ow head) and inf ilt rat ion int o t he superior v ena c av a (blac k ar r ow head). T he at elec t at ic lung dist al t o t he mass demonst rat es great er enhanc ement (c ur v ed ar r ow s). Enhanc ement of t he azy gos v ein (w hit e ar r ow ) due t o c ollat eral f low . B: More c audally , c omput ed t omography show s t he mass c irc umf erent ially around a narrow ed right main st em bronc hus ext ending t ow ards t he aort a.

F igure 7- 34 Unresec t able bronc hogenic c arc inoma. A, B: Sequent ial c omput ed t omography sc ans demonst rat e ext ensiv e mediast inal inv asion int o t he subc arinal area (S) w it h c irc umf erent ial narrow ing of t he bronc hus int ermedius (ar r ow ) and t he right pulmonary art ery (ar r ow heads). A small peric ardial ef f usion also is present .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

982

7 - Lung

F igure 7- 35 Unresec t able pleomorphic c arc inoma of t he t rac hea. A: T ransaxial c omput ed t omography demonst rat es ext ensiv e inf ilt rat ion of t he mediast inum bet w een t he t rac hea and medial aspec t of t he aort ic arc h, w it h t he mass abut t ing t he esophagus. B: Volume- rendered sagit t al c omput ed t omography image show s t he large t rac heal t umor inv ading t he mediast inum (ar r ow heads).

F igure 7- 36 Unresec t able bronc hogenic c arc inoma. A, B: Sequent ial c omput ed t omography images show a large, nec rot ic squamous c ell c arc inoma of t he lef t upper lobe inv ading t he mediast inal f at (f ) and t he lef t pulmonary art ery (p).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

983

7 - Lung

F igure 7- 37 Unresec t able bronc hogenic c arc inoma. Comput ed t omography demonst rat es a large c ent ral lef t lung mass, w hic h is c ausing c omplet e c ollapse of t he lef t lung, and inv ading t he proximal lef t pulmonary art ery (ar r ow s). T he dist al at elec t at ic lung (lu; lef t upper lobe, ll; lef t low er lobe) enhanc es, and t here is a lef t pleural ef f usion.

Relat iv ely c ent ral primary neoplasms, espec ially adenoc arc inomas, f requent ly ext end proximally in t he submuc osa of t he bronc hus f or a c onsiderable lengt h. Peribronc hial sof t t issue t hic kening may be depic t ed on CT (F ig. 7- 40), somet imes w it h ext ension int o t he mediast inal f at . Suc h a f inding should prompt a deep biopsy at bronc hosc opy f or c orroborat ion. CT demonst rat ion of ext ension of t umor int o t he hilar region w it h inv olv ement of t he origin of t he main lef t or right bronc hus, or proximal lef t or right pulmonary art ery , or bot h t he superior and inf erior pulmonary v eins, w ould st rongly suggest t hat a pneumonec t omy is required f or suc c essf ul resec t ion. Wit h proximal main bronc hial inv olv ement only , lobec t omy w it h sleev e resec t ion and bronc hoplast y may be f easible. Ev en if t here is inv asion of t he c arina, a pneumonec t omy and sleev e resec t ion may be possible in selec t ed c ases, alt hough t he morbidit y and mort alit y are relat iv ely high. Similarly , t umor ext ending ac ross a f issure w ould suggest t he need f or a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

984

7 - Lung pneumonec t omy or, perhaps, an ext ended lobec t omy (F ig. 7- 41). In pat ient s w it h marginal pulmonary f unc t ion or perhaps sev ere c ardiac disease, c onsidered c andidat es only f or a lobec t omy , t he CT f indings af f ec t operabilit y rat her t han resec t abilit y (106).

F igure 7- 38 Resec t able bronc hogenic c arc inoma. Comput ed t omography show s a large right low er lobe c arc inoma abut t ing t he mediast inum, adjac ent t o t he lef t at rium, air- f illed esophagus, and azy gos v ein, w it hout def init e inv asion. At surgery , t he lesion did not inv ade t he mediast inum, and mildly enlarged right hilar ly mph nodes w ere reac t iv e.

A primary c ent ral bronc hogenic c arc inoma, c ausing dist al obst ruc t ion/pneumonit is, of t en c an be separat ed f rom t he lat t er on c ont rast enhanc ed CT , and if needed, MR images. Lung c onsolidat ion/at elec t asis appears higher in at t enuat ion v alue or in signal int ensit y t han t he proximal neoplast ic mass (see F igs. 7- 33 and 7- 37). Suc h def init ion of t he limit s of t he primary t umor c an be import ant in pat ient s undergoing radiat ion t herapy (117). T he abilit y of CT t o depic t t he ext rabronc hial ext ent of c arc inomas inv olv ing t he dist al t rac hea or proximal bronc hi, and it s relat ion P.447

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

985

7 - Lung t o adjac ent major v asc ular st ruc t ures c an be v aluable if laser phot oresec t ion t herapy is planned. T he presenc e of subst ant ial peribronc hial t umor ext rinsic t o a bronc hial obst ruc t ion, w hic h c annot be ev aluat ed by f iberopt ic bronc hosc opy , is a predic t or of poor response t o laser phot oresec t ion t herapy (455,667).

F igure 7- 39 Bronc hogenic c arc inoma. A: Comput ed t omography show s a large part ially nec rot ic right upper lobe mass (m), oc c luding t he right upper lobe pulmonary art ery (w hit e ar r ow ) and ext ending int o t he right superior pulmonary v ein (blac k ar r ow ). B: A more c audal c omput ed t omography image show s t umor ext ending int o t he lef t at rium (LA). A right empy ema is sec ondary t o a c onc omit ant right low er lobe pneumonia.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

986

7 - Lung

F igure 7- 40 An ext ensiv e right upper lobe adenoc arc inoma narrow s t he lobar bronc hus (ar r ow ) and ext ends proximally in t he submuc osa, produc ing t hic kening of t he post erior w all of t he right main st em bronc hus (ar r ow heads). T he mediast inum and t he superior v ena c av a also are inv aded, and a small right pleural ef f usion is present .

Peripheral bronc hogenic c arc inoma may direc t ly inv ade t he adjac ent pleura, or ev en peric ardium, somet imes by ext ending along t he periv asc ular- ly mphat ic sheat hs. CT may demonst rat e a small pleural or peric ardial ef f usion not ev ident on c onv ent ional radiographs. Aspirat ion of t his f luid, under ult rasound guidanc e if nec essary , may be w arrant ed t o det ermine if malignant c ells are present , w hic h P.448 P.449 c ould ef f ec t management in some pat ient s. PET imaging also may be helpf ul in suggest ing t hat a pleural ef f usion is benign or malignant (121,535). Inv olv ement of t he pariet al pleura and c hest w all may be present in t he absenc e of a pleural ef f usion. T he v alue of CT in t he det erminat ion of c hest w all inv asion is somew hat limit ed (555). Asy mmet ry of t he c hest w all t issues

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

987

7 - Lung may be due t o pat ient posit ioning or a normal v ariat ion and c an misleadingly simulat e c hest w all inv asion (167,457). Similar t o c omment s made regarding mediast inal inv asion, mere c ont iguit y of a peripheral lung c arc inoma w it h t he pleura on CT is not indic at iv e of inv asion. T he presenc e of rib or v ert ebral body dest ruc t ion or a sof t t issue mass ext ernal t o t he ribs inf ilt rat ing t he f at and musc les are absolut e signs of c hest w all inv asion (F igs. 7- 42, 7- 43, 744), but are det ec t ed only w it h adv anc ed t umors (487). CT f indings suc h as more t han 3 c m of c ont ac t bet w een t he lung mass and t he pleura, t he presenc e of adjac ent pleural t hic kening, and an obt use angle bet w een t he pulmonary neoplasm and t he pleural surf ac e may suggest pariet al pleural inv asion but are neit her v ery sensit iv e nor spec if ic . Pleural t hic kening may be due t o benign c auses, ev en in a pat ient w it h a peripheral bronc hogenic c arc inoma, suc h as c onc omit ant inf lammat ion, old sc arring, or plaque f ormat ion. Loss of t he normally present ext rapleural f at lay er also is suggest iv e of inv asion (see F igs. 7- 42 and 7- 44); t his f inding may be more easily rec ognized on MRI but is not spec if ic f or pariet al pleura inv asion (205). An abnormal sof t t issue mass in t he c hest w all may be seen on longit udinal relaxat ion t ime (T 1)- w eight ed images, somet imes ac c ompanied by abnormal high signal f ollow ing gadolinium enhanc ement or on t ransv erse relaxat ion t ime (T 2)- w eight ed images (442). Bot h diagnost ic pneumot horax t o det ermine if t he neoplasm loses c ont iguit y w it h t he c hest w all and dy namic CT during respirat ion t o asc ert ain w het her t he t umor mov es w it h respec t t o t he pariet al pleura hav e been adv oc at ed t o assess f or c hest w all inv asion (627,660). How ev er, benign adhesions may produc e f alse- posit iv e result s and t he addit ional imaging required is rarely , if ev er, w arrant ed. T he most spec if ic indic at or of pariet al pleural inv asion is t he c linic al presenc e of f oc al c hest w all pain. Ev en in pat ient s w ho are st age IIIa (T 3) by v irt ue of t umor penet rat ing t hrough t he pariet al pleura, suc h c hest w all inv asion is not nec essarily a c ont raindic at ion t o surgery ; prognosis is reasonable if t he inv asion is limit ed and no mediast inal ly mph node met ast ases are present (543). T he inv olv ed c hest w all may be resec t ed en bloc along w it h t he adjac ent primary neoplasm; how ev er, suc h a proc edure is assoc iat ed w it h inc reased operat iv e morbidit y and mort alit y .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

988

7 - Lung

F igure 7- 41 Bronc hogenic c arc inoma (CA) originat ing in t he superior segment of t he right low er lobe, ext ends ac ross t he major f issure (ar r ow ) int o t he right upper lobe (l).

F igure 7- 42 Bronc hogenic c arc inoma, c hest w all inv asion. A, B: Cephaloc audal c omput ed t omography images demonst rat e a c av it ary squamous c ell c arc inoma of t he right low er lobe dest roy ing a post erior rib (ar r ow ), oblit erat ing t he ext rapleural f at and inv ading t he c hest w all ext ernal t o t he rib (ar r ow heads). Pat ient , w ho present ed w it h dy sphagia, also has esophagit is.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

989

7 - Lung

F igure 7- 43 Large c arc inoma of right upper lobe dest roy ing a rib (ar r ow ) and f oc ally inv ading t he c hest w all (ar r ow heads).

F igure 7- 44 Carc inoma of lef t low er lobe inv ading and dest roy ing t he adjac ent v ert ebral body . Neoplasm also ext ends int o t he adjac ent ext rapleural

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

990

7 - Lung f at (ar r ow heads).

In some pat ient s w it h superior sulc us (ext reme apex of lung) bronc hogenic c arc inomas, c urat iv e resec t ion may be at t empt ed. Almost all of t hese neoplasms are non–small c ell, and t hey t y pic ally arise dorsal t o t he groov e f or t he subc lav ian art ery . T umors t hat do not ext end t hrough t he apic al f at may be operat ed on primarily . Neoplasms t hat demonst rat e inv asion abov e t he lung apex (Panc oast t umors) usually are t reat ed init ially by radiat ion t herapy (somet imes in c onjunc t ion w it h c hemot herapy ), f ollow ed by surgic al resec t ion if t he t umor responds (433,599,632). F ormerly it w as generally ac c ept ed t hat t he ext ent of t hese neoplasms and t he proximit y of t umor t o t he subc lav ian v essels and brac hial plexus is depic t ed more ac c urat ely w it h c oronal and sagit t al MRI c ompared w it h CT (F ig. 7- 45) (226). How ev er, rec ent experienc e w it h mult iplanar rec onst ruc t ions of t hin- sec t ion MDCT images suggest equiv alenc e in display ing disrupt ion of t he apic al f at lay er and ext ension of t he t umor int o t he low er nec k. Inv olv ement of t he adjac ent ribs and v ert ebral bodies usually is bet t er seen w it h CT (F ig. 7- 46) (599). Inv asion of t he subc lav ian art ery , a v ert ebral body , or upper brac hial plexus inv olv ement , or mediast inal ly mph node met ast ases presages an exc eedingly poor prognosis, and usually c ont raindic at es surgery . Simult aneous lung c arc inomas may be depic t ed on CT (F ig. 7- 47), one of w hic h w as not suspec t ed on plain c hest radiography (275), in up t o 2% of pat ient s being ev aluat ed P.450 P.451 f or possible lung c anc er. A phy sic ally dist inc t and separat e lung neoplasm w it h a dif f erent c ell t y pe is c onsidered a sy nc hronous primary lesion and should be st aged independent ly . Separat e masses w it h t he same hist ology may be c onsidered sy nc hronous if t here is no ev idenc e of c arc inoma in t he ly mphat ic s and ly mph nodes c ommon t o bot h. Alt hough t hese lesions are c at egorized as T 4, suc c essf ul resec t ions of bot h, somet imes t hrough a median st ernot omy if in dif f erent lungs, has been ac c omplished in selec t ed c ases.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

991

7 - Lung

F igure 7- 45 A, B: Coronal and sagit t al magnet ic resonanc e images show dest ruc t ion of a post erior rib (ar r ow s) w it h t umor inv ading t he c hest w all (ar r ow heads), c ont ac t ing t he brac hial plexus and right subc lav ian art ery ant eriorly .

F igure 7- 46 Superior sulc us c arc inomas. A: Comput ed t omography show s a large mass (M) f illing t he lef t lung apex, inv ading and dest roy ing t he lef t sec ond post erior rib (ar r ow ). B: In anot her pat ient , c omput ed t omography show s a lef t superior sulc us c arc inoma inv ading an adjac ent v ert ebral body .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

992

7 - Lung

F igure 7- 47 Sy nc hronous c arc inomas. A: Comput ed t omography demonst rat es a 5- c m lobulat ed mass in t he middle lobe. B: More c ephalad, a 1.6- c m spic ulat ed mass also is seen in t he lef t upper lobe. C : F used 18f luorine–posit ron emission t omography /c omput ed t omography image demonst rat es av id upt ake in bot h lesions. Bot h w ere resec t ed v ia median st ernot omy and demonst rat ed large c ell c arc inoma w it h neuroendoc rine f eat ures and a moderat ely dif f erent iat ed squamous c ell c arc inoma respec t iv ely .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

993

7 - Lung

F igure 7- 48 Hilar ly mph node met ast asis f rom a right low er lobe c arc inoma. Comput ed t omography demonst rat es a nodal mass in t he right hilum (ar r ow heads), and t he primary c arc inoma (ar r ow ).

PET imaging generally has limit ed v alue in assessing t he T f eat ures of a bronc hogenic c arc inoma. Bronc hial w all and v asc ular inv asion usually are dif f ic ult t o assess. How ev er, high st andard upt ake v alues (SUVs) do c orrelat e w it h t he aggressiv eness of t he neoplasm hist ologic ally and prov ide some prognost ic inf ormat ion. Me dia stina l Ly mph Node Sta tus (the N Fa ctor). CT c an prov ide import ant inf ormat ion about t he nodal st at us in pat ient s w it h bronc hogenic c arc inoma. Ident if ic at ion and loc alizat ion of enlarged mediast inal ly mph nodes c an serv e as a usef ul guide f or selec t ion of t he opt imal semi- inv asiv e t issue sampling st aging proc edure (e.g., mediast inosc opy , mediast inot omy , t ransbrac hial or t ranst horac ic needle biopsy ) t o obt ain t issue and c orroborat e ly mph node met ast ases, bef ore at t empt ing c urat iv e resec t ion of a bronc hogenic c arc inoma (see T able 5- 2) (103,297). Cont rast - enhanc ed CT is a sensit iv e depic t er of hilar ly mph node enlargement (F ig. 7- 48), being able t o det ec t ly mph nodes 6 mm or larger in diamet er

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

994

7 - Lung (163,554). Nev ert heless, hilar ly mph node assessment has lit t le relev anc e in most pat ient s w it h bronc hogenic c arc inoma. It is t he presenc e of direc t mediast inal ext ension of t he primary neoplasm or mediast inal ly mph node met ast ases (see F ig. 7- 30; F ig. 7- 49) t hat c ont raindic at es surgery . Alt hough P.452 P.453 t he presenc e of ipsilat eral hilar ly mph node inv olv ement (N1) alt ers t he st age and not ably diminishes t he prognosis of t he pat ient , it neit her makes t he pat ient unresec t able (and w ould not af f ec t operabilit y if t he nodes c an be dissec t ed f ree of t he mediast inum w it hout nec essit at ing a pneumonec t omy ) nor ac c urat ely predic t s t he presenc e of mediast inal ly mph node inv olv ement . Met ast at ic c arc inoma may oc c ur in mediast inal ly mph nodes in 25% of pat ient s w it h negat iv e hilar nodes. T heref ore, in t he ov erall st aging of bronc hogenic c arc inoma, hilar ev aluat ion is of minor import anc e and rigorous ef f ort s at hilar st aging are usually not w arrant ed, unless t he pat ient is c learly not a c andidat e f or a pneumonec t omy (pulmonary f unc t ion st at us w ould permit only a lobec t omy ), w hic h may be required if t he nodal met ast ases are f ound t o enc ase a main pulmonary art ery at surgery .

F igure 7- 49 Hilar and mediast inal ly mph node met ast ases. A: Comput ed t omography demonst rat es a c av it ary mass in t he lef t low er lobe, and assoc iat ed lef t hilar ly mph node enlargement (ar r ow ). B: More c ephalad image show s a c onc omit ant nec rot ic subc arinal nodal mass (ar r ow ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

995

7 - Lung T ransbronc hosc opic needle aspirat ion of t he lat t er mass disc losed poorly dif f erent iat ed squamous c ell c arc inoma.

F igure 7- 50 Bulky ly mphadenopat hy . A: Comput ed t omography at lev el of t he aort ic arc h (A demonst rat es markedly enlarged right parat rac heal ly mph nodes (ar r ow s). B: More c audal, t he primary squamous c ell c arc inoma narrow ing t he bronc hus int ermedius (ar r ow head) is seen. Peripheral enhanc ement of not ably enlarged subc arinal ly mph nodes (n due t o c et nt ral nec rosis, is present .

F igure 7- 51 Aort opulmonary w indow ly mph node met ast ases. A, B: Sequent ial c ephaloc audal c omput ed t omography images demonst rat e ly mphadenopat hy (ar r ow s) in t he aort opulmonary w indow , along t he c ourse of t he lef t rec urrent

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

996

7 - Lung lary ngeal nerv e, in a pat ient w it h a lef t upper lobe c arc inoma w ho present ed c linic ally w it h hoarseness.

T he presenc e of ipsilat eral mediast inal ly mph node met ast ases (N2) sec ondary t o bronc hogenic c arc inoma generally presages a v ery poor prognosis and usually indic at es inc urable disease, and t radit ionally has been c onsidered a c ont raindic at ion t o t horac ot omy , regardless of c ell t y pe or loc at ion. Selec t ed pat ient s, how ev er, hav e improv ed surv iv al af t er resec t ion of limit ed mediast inal nodal disease (st age IIIa), f ollow ed in most c ases (or prec eded) by adjuv ant radiat ion t herapy or c hemot herapy . Well- dif f erent iat ed squamous c ell c arc inoma w it h only int ranodal grow t h w it hin a node in t he ipsilat eral t rac heobronc hial area w ould be a nonc ont rov ersial example. How ev er, ext ension of t umor t hrough t he c apsule, usually ac c ompanied by bulk enlargement of t he ly mph node (F ig. 7- 50), generally indic at es t hat neoplast ic disease almost c ert ainly has spread t o ot her nodes or ent ered t he sy st emic c irc ulat ion. Deep c erv ic al/suprac lav ic ular ly mph node met ast ases may oc c ur in up t o 10% of pat ient s at present at ion, w it h only about 25% of t hose inv olv ed nodes being palpable c linic ally (most f requent w it h squamous c ell c arc inoma). At t ent ion should be direc t ed t o t his nodal group on t he c ephalad CT images of t he t horax (144,616). T he loc at ion of t he primary c arc inoma det ermines t he usual ly mphat ic pat hw ay s of t umor spread t o t he regional ly mph nodes (463). Canc ers originat ing in t he right lung t end t o met ast asize init ially t o t he ipsilat eral t rac heobronc hial (hilar) nodes [10R] (see F ig. 5- 56) and subsequent ly t o t he right parat rac heal nodes [4R,2R]. Suc h neoplasms rarely met ast asize t o c ont ralat eral ly mph nodes (N3), unless t he hist ology is small c ell undif f erent iat ed c arc inoma, w hereas c anc ers of t he lef t lung c ommonly spread t o t he right parat rac heal nodes subsequent t o ipsilat eral inv olv ement (see F igs. 7- 25 and 7- 26). Carc inomas of t he LUL usually met ast asize init ially t o nodes in t he aort opulmonary w indow [5,4L] (see F ig. 7- 27; F ig. 7- 51) and bot h lef t upper and low er lobe lesions may spread f irst t o t he lef t t rac heobronc hial region [10L]. Inv olv ement of t he prev asc ular ly mph nodes [6] almost alw ay s is prec eded by nodal disease in t he parat rac heal area. Canc ers of t he middle lobe and bot h low er lobes of t en af f ec t t he subc arinal nodes [7] early in t heir disseminat ion (see F igs. 7- 30 and 7- 49), and low er lobe lesions also may ext end t o t he paraesophageal [8], pulmonary ligament [9], and supradiaphragmat ic nodes [14]. Know ledge of t he expec t ed drainage pat t ern c an be v aluable in selec t ed c ases. It w ould be ext remely unlikely f or a right

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

997

7 - Lung lung c arc inoma t o spread only t o aort opulmonary ly mph nodes, and isolat ed enlargement of nodes in t his region not ed on CT in suc h a pat ient generally c an be presumed due t o anot her c ause, suc h as old granulomat ous disease. T he report ed sensit iv it y , spec if ic it y , and ac c urac y of CT in det ec t ing mediast inal nodal met ast ases hav e been ext remely v ariable, ev en w hen using apparent ly t he same c rit eria and similar equipment and t ec hnique (73,128,164,224,376,454,486,544,575,635). F alse- posit iv e rat es hav e v aried f rom 20% t o 45%, and f alse–negat iv e rat es f rom 7% t o 39%. An ov erall sensit iv it y and ac c urac y of about 65% seems reasonable. Bot h are higher w it h squamous c ell c arc inoma t han adenoc arc inoma. Pragmat ic ally , t he larger t he ly mph node appears on CT , t he great er t he c hanc e t hat it w ill be inv olv ed w it h met ast asis. Our diagnost ic c rit eria on CT sc ans, largely c hosen t o maximize sensit iv it y , is t hat any mediast inal ly mph node less t han 1 c m in long axis diamet er is c onsidered unlikely t o harbor met ast at ic disease. T hose nodes 1 t o 2 c m in diamet er are c onsidered highly suspic ious; suc h enlargement c an be c aused by eit her neoplasm or granulomat ous disease. While mediast inal ly mph nodes more t han 2 c m in diamet er in a pat ient w it h a know n primary bronc hogenic c arc inoma almost alw ay s are due t o neoplast ic inv olv ement , hist ologic c orroborat ion is st ill st rongly suggest ed. Wit h t he bet t er def init ion now av ailable w it h MDCT enhanc ed sc ans, c ent ral nec rosis or hy peremia in ev en a normal size ly mph node makes it highly suspic ious f or met ast at ic disease. Size c rit eria alone w ill nev er be t ot ally reliable in st aging t he mediast inal ly mph nodes (340). T he demonst rat ion of enlarged mediast inal ly mph nodes in t he pat ient w it h bronc hogenic c arc inoma does not aut omat ic ally imply met ast at ic disease (F ig. 7- 52). As already st at ed, P.454 approximat ely 20% w ill be f alse–posit iv es relat ed t o pre- or c oexist ing inf ec t ious/inf lammat ory disease. Ot her morphologic f eat ures of ly mph nodes, suc h as shape, at t enuat ion v alue, or marginat ion, hav e not prov ed of prac t ic al v alue in t his dif f erent iat ion, w it h t he exc ept ion of c ent ral f at , w hic h inv ariably indic at es benign adenopat hy . Bec ause of t his nonspec if ic it y , enlarged ly mph nodes should be biopsied f or c onf irmat ion of disseminat ed disease; a pat ient should not be denied a pot ent ially c urat iv e resec t ion based solely on radiologic size c rit eria of a mediast inal ly mph node.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

998

7 - Lung

F igure 7- 52 Reac t iv e ly mph nodes. Comput ed t omography demonst rat es mildly enlarged pret rac heal ly mph nodes (ar r ow heads) in a pat ient w it h a right low er lobe squamous c ell c arc inoma. Bot h mediast inosc opic biopsy and nodal sampling at t horac ot omy disc losed only reac t iv e inf lammat ory c hanges in t hese nodes.

Ly mph nodes c ont aining met ast ases t y pic ally missed by CT are t hose t hat are st ill normal in size. Suc h mic rosc opic met ast ases oc c ur in about 15% of pat ient s w it h c linic al st age I bronc hogenic c arc inoma. T hese same pat ient s somet imes hav e negat iv e result s also at mediast inosc opy , and t heir N2 st at us is disc ov ered only at t horac ot omy w it h nodal sampling. T heir prognosis and surv iv al rat e, w it h adjuv ant post operat iv e radiat ion and/or c hemot herapy , is subst ant ially bet t er t han pat ient s w it h N2 disease est ablished at mediast inosc opy (553). Surgic al nodal sampling proc edures dev eloped bef ore t he adv ent of CT f or st aging purposes, inc luding t ransc erv ic al mediast inosc opy and parast ernal mediast inot omy , not ably reduc ed t he perc ent age of unnec essary t horac ot omies f rom 40% t o 10% or less. Y et , t hese proc edures hav e some def init e limit at ions and are only 85% ac c urat e in mediast inal nodal ev aluat ion. T he mediast inosc ope does not ev aluat e all of t he mediast inal c ompart ment s. Only ly mph nodes in t he middle mediast inum, prec arinal and ant erior and lat eral t o t he t rac hea and post erior t o t he major v essels (brac hioc ephalic art eries and v eins, superior v ena c av a, and asc ending aort a), are ac c essible t o biopsy . Approximat ely 8% of pat ient s w it h bronc hogenic c arc inoma and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

999

7 - Lung negat iv e mediast inosc opy hav e mediast inal ly mph node met ast ases at surgery . Suc h inv olv ed ly mph nodes are usually in t he ant erior mediast inum (prev asc ular spac e), aort opulmonary w indow , and post erior subc arinal region, but somet imes met ast ases are det ec t ed in ly mph nodes t hat w ere ac c essible t o mediast inosc opy . Mediast inosc opy c an be used f or parat rac heal and ant erior subc arinal ly mphadenopat hy (see F igs. 7- 26, F ig. 7- 50, and F ig. 751). Aort opulmonary w indow adenopat hy is best approac hed v ia a lef t parast ernal mediast inot omy (see F ig. 7- 27). T ransbronc hosc opic needle biopsy c an be used f or post erior subc arinal (see F igs. 7- 30 and 7- 49) and somet imes parat rac heal ly mphadenopat hy . In some selec t ed c irc umst anc es, CT - guided perc ut aneous needle biopsy may be usef ul t o sample enlarged mediast inal ly mph nodes. T he ac c urac y of t hese t issue- sampling t ec hniques c an be inc reased w hen direc t ed by CT t o areas of morphologic abnormalit y , inc luding c linic ally unsuspec t ed met ast ases in t he adrenal and liv er. Alt hough t he bronc hosc opic rec ognit ion of w idening and f ixat ion of t he c arina may st rongly suggest mediast inal inv olv ement w it h t umor, t he CT demonst rat ion of enlarged ly mph nodes in t he subc arinal area helps in t he earlier appropriat e selec t ion of pat ient s f or t ransbronc hial needle aspirat ion. Ev idenc e of assoc iat ed abnormalit ies, suc h as superior v ena c av a obst ruc t ion or dest ruc t ion of a v ert ebral body , c ombined w it h ext ensiv e ly mphadenopat hy , may prec lude t he need f or addit ional st aging proc edures if t he hist ology of t he primary lesion has been est ablished. Whet her CT is suf f ic ient ly sensit iv e t o sc reen out pat ient s w ho w ould not benef it f rom rout ine t ransc erv ic al mediast inosc opy or lef t ant erior parast ernal mediast inot omy remains c ont rov ersial (456). Some surgeons adv oc at e mediast inosc opy in all pat ient s c onsidered t o be c andidat es f or resec t ion. Ot hers c ont end t hat in a pat ient w it h a negat iv e CT examinat ion of t he mediast inum and upper abdomen, one c an proc eed direc t ly t o t horac ot omy , espec ially if t he primary t umor is a squamous c ell c arc inoma or is small and peripheral. Alt hough t here w ill alw ay s be a perc ent age (somet imes as high as 39%) of f alse–negat iv e CT sc ans due t o mic rosc opic met ast ases w it hin normal size ly mph nodes (195), t his may hav e lit t le c linic al signif ic anc e. As w as already emphasized, a relat iv ely f av orable prognosis st ill may be ac hiev ed in pat ient s w it h limit ed int ranodal disease, det ec t ed by rout ine int raoperat iv e biopsy of normal- appearing mediast inal ly mph nodes, w hen supplement al post operat iv e mediast inal irradiat ion or c hemot herapy is administ ered; t hus resec t ion w ould st ill hav e been appropriat e.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1000

7 - Lung PET is superior t o CT (and MRI) in st aging t he mediast inal ly mph nodes in pat ient s w it h bronc hogenic c arc inoma (580). In c ombinat ion w it h CT , it prov ides c ompliment ary noninv asiv e f unc t ional inf ormat ion t o simple size c rit eria, improv ing t he ov erall ac c urac y of c linic al st aging. PET prov ides phy siologic dat a rat her t han morphologic inf ormat ion. T he most c ommonly used agent f or PET t umor imaging is deoxy gluc ose linked t o 18-

f luorine, or F DG. T his agent c ompet es w it h gluc ose f or t ransport int o c ells and f or phosphory lat ion by hexokinase, bot h of w hic h are inc reased in t umors c ompared w it h nonneoplast ic c ells. How ev er, inc reased gluc ose met abolism is not spec if ic f or malignant neoplasm, and c an oc c ur w it h inf ec t ious (F ig. 7- 53) and inf lammat ory proc esses, as w ell as in some normal anat omic st ruc t ures, suc h as brow n f at and musc les inc luding t he heart (24). Also, some c arc inoid t umors (see F ig. 7- 15) and w ell- dif f erent iat ed adenoc arc inomas and bronc hoalv eolar c ell c arc inomas (F ig. 7- 54) may not demonst rat e signif ic ant t rac er upt ake (279). Inc reased F DG upt ake in a normal size ly mph node is highly suggest iv e of met ast at ic disease. T he absenc e of inc reased upt ake in an enlarged node is st rongly indic at iv e of t he absenc e of met ast ases. Ov erall sensit iv it y is about 83% and spec if ic it y about 90%, approac hing t he result s w it h mediast inosc opy (276). T he inf ormat ion f rom t he PET examinat ion in c onjunc t ion w it h t he CT f indings c an be used t o more ac c urat ely guide t hose semi- inv asiv e mediast inal node- sampling t ec hniques (e.g., mediast inosc opy , mediast inot omy , t ransbronc hial needle biopsy ) already P.455 desc ribed. Nev ert heless, F DG PET is not inf allible f or t he c onf irmat ion or exc lusion of N2 or N3 disease in non–small c ell lung c anc er. As w it h CT , f alse–negat iv e examinat ions oc c ur w it h mic rosc opic f oc i of t umor. Also, f alse–posit iv es c an result f rom inf lammat ory and inf ec t ious nodal disease.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1001

7 - Lung

F igure 7- 53 Ac t iv e t uberc ulosis. A Comput ed t omography demonst rat es a 15mm spic ulat ed c av it ary lesion (ar r ow ) in ant erior segment of t he lef t upper lobe, in an elderly w omen w it h emphy sema. B: F usion 18- f luorine–posit ron emission t omography /c omput ed t omography image demonst rat es marked inc reased upt ake in t he lesion, int erpret ed as c ompat ible w it h a primary c arc inoma. Pat ient dec lined immediat e f urt her ev aluat ion of presumed c arc inoma f or f amilial reasons. C : Comput ed t omography 3 mont hs lat er at t ime of sc heduled needle biopsy demonst rat es marked int erv al grow t h of t he lesion, w it h new peripheral lung c onsolidat ion. Aspirat ion spec imens disc losed M. t uber c ulosis.

F DG PET st udies int erpret ed w it hout c orrelat iv e anat omic imaging st udies (CT or MRI) are less ac c urat e. Separat ing hilar f rom mediast inal nodal disease may be dif f ic ult , and w it h c ent ral bronc hogenic c arc inomas separat ing upt ake in t he t umor f rom nodes may be impossible. Combined int erpret at ion of dual

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1002

7 - Lung

modalit y f used PET /CT images opt imizes t he st rengt hs of eac h; t he sensit iv it y and spec if ic it y of eit her t ec hnique alone is improv ed. CT c an help resolv e some f alse- posit iv e PET f indings. CT and PET should be v iew ed as c omplement ary ; somet imes one is bet t er, somet imes t he ot her. Ev a lua tion of Dista nt Me ta sta se s (the M Fa ctor). Some pat ient s t hought t o be resec t able f or c ure hav e oc c ult met ast at ic disease present out side t he t horax (M1) (532). Suc h ext rat horac ic met ast ases may arise f rom spread v ia t he ly mphat ic sy st em or t hrough t he pulmonary v eins direc t ly int o t he sy st emic c irc ulat ion. Aut opsies perf ormed w it hin 30 day s of at t empt ed c urat iv e resec t ions, bef ore t he int roduc t ion of CT , hav e show n t hat t he f requenc y of suc h P.456 oc c ult met ast ases in non–small c ell bronc hogenic c arc inoma at t he t ime of present at ion may be as high as 30% in pat ient s w it h adenoc arc inoma or large c ell c arc inoma, but generally less t han 15% w it h squamous c ell c arc inoma. Also, w it h squamous c ell c arc inoma, it is rare t o hav e ext rat horac ic met ast ases in t he absenc e of mediast inal nodal met ast ases (557).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1003

7 - Lung

F igure 7- 54 Mixed w ell dif f erent iat ed adenoc arc inoma/bronc hoalv eolar c ell c arc inomas. A: Comput ed t omography demonst rat es a c omplex mass in post erior segment of t he right upper lobe, w it h peripheral solid sof t t issue element s (st r aight ar r ow ), and more c ent ral c y st ic regions (pseudoc av it at ion) (c ur v ed ar r ow ). B: 18- F luorine–posit ron emission t omography show ed an st andard upt ake v alue of 1.9, int erpret ed as most likely a c hronic inf lammat ory proc ess. C : In anot her pat ient , c omput ed t omography again demonst rat es a c omplex lef t upper lobe mass, w it h ant erior solid lobulat ed sof t t issue element s (ar r ow ), and a larger post erior c y st ic region (pseudoc av it at ion) (ar r ow heads). 18- F luorine- posit ron emission t omography show ed mild inc reased upt ake w it h an st andard upt ake v alue of 1.9; inf lammat ion w as f av ored. D: Comput ed t omography –guided needle aspirat ion of t he sof t t issue c omponent disc losed w ell dif f erent iat ed adenoc arc inoma.

T he most c ommon sit es of oc c ult ext rat horac ic met ast ases in order are t he brain, bone, liv er and adrenals. CT st aging f or bronc hogenic c arc inoma should

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1004

7 - Lung ext end int o t he abdomen t o assess t he liv er and adrenals (F igs. 7- 55 and 7-

56). Suc h c onc omit ant assessment now c an be ac c omplished easily w it h MDCT helic al t ec hnique. T he liv er is almost nev er t he only demonst rable sit e of met ast ases, unless t he primary lung neoplasm is an adenoc arc inoma. Abnormal liv er f unc t ion t est s are neit her a sensit iv e nor spec if ic indic at or of liv er met ast ases. Suspic ious lesions c an be biopsied, of t en w it h ult rasound guidanc e, if t he result s w ill impac t t herapeut ic dec isions. CT is v ery sensit iv e in det ec t ing adrenal masses. Alt hough most pat ient s w it h met ast at ic enlargement of t he adrenals hav e CT ev idenc e of mediast inal ly mph node enlargement , P.457 P.458 oc c asionally t he adrenal is t he only sit e of met ast ases t o c ont raindic at e surgery . T he v ast majorit y of pat ient s w it h adrenal met ast ases do not hav e c linic al signs of adrenal insuf f ic ienc y . An adrenal mass is not sy nony mous w it h met ast asis; inc ident al benign nonhy perf unc t ioning adenomas oc c ur w it h a similar f requenc y as t hat of met ast asis in pat ient s w it h bronc hogenic c arc inoma (437). A small (less t han 3- c m), w ell- c irc umsc ribed adrenal mass w it h a homogeneous relat iv ely low at t enuat ion v alue (less t han 20 HU), bec ause of it s lipid c ont ent , and no peripheral enhanc ement , almost c ert ainly represent s an adenoma. Most lesions exc eeding 3 c m in diamet er, espec ially t hose t hat are inhomogeneous and hav e a t hic k enhanc ing w all, represent met ast ases. If an indet erminat e adrenal mass is seen on post c ont rast CT images, t here may be merit in ac quiring t hin- c ollimat ion nonc ont rast sc ans of t he adrenal about 1 hour lat er; subst ant iv e at t enuat ion v alues abov e 30 HU suggest met ast asis, w hereas dominant v alues below 20 HU an inc ident al nonhy perf unc t ioning adenoma. If t he mass is st ill equiv oc al, MRI is adv oc at ed (490). Relat iv ely low signal int ensit y on bot h T 1- and T 2- w eight ed images w it h no enhanc ement post –gadolinium administ rat ion and signal dropout on opposed phase c hemic al shif t imaging is c harac t erist ic of a benign adenoma (51). Perc ut aneous needle biopsy under CT or ult rasound- direc t ed guidanc e may be required t o doc ument , or P.459 help exc lude, adrenal disseminat ion if t he pat ient is ot herw ise deemed operable (F ig. 7- 57).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1005

7 - Lung

F igure 7- 55 Bronc hogenic c arc inoma w it h met ast ases. A: Comput ed t omography demonst rat es a 4- c m irregular right apic al mass (m). B: More c audal image demonst rat es right hilar (ar r ow ) and subc arinal (ar r ow head) ly mphadenopat hy . C A het erogenous right adrenal mass (ar r ow ) is seen. D: An enhanc ing enlarged lef t paraort ic ly mph (ar r ow ) also present . E: F usion 18f luorine–posit ron emission t omography /c omput ed t omography image show s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1006

7 - Lung

markedly inc reased upt ake in t he primary apic al t umor (st r aight ar r ow ) as w ell as in t he right adrenal met ast asis (c ur v ed ar r ow ).

F igure 7- 56 Small c ell undif f erent iat ed c arc inoma w it h liv er met ast ases. A Comput ed t omography show s t he small primary t umor (ar r ow ) in t he lef t upper lobe, w it h ext ensiv e mediast inal ly mph node met ast ases (n). B: More c audal image of upper abdomen demonst rat es mult iple peripherally enhanc ing liv er met ast ases (ar r ow heads) plus a lef t adrenal met ast asis (ar r ow ).

F igure 7- 57 Adrenal met ast asis f rom bronc hogenic c arc inoma. A: Comput ed t omography demonst rat es a small mass in t he right adrenal (ar r ow head) in pat ient w it h a right upper lobe c arc inoma. Mild mediast inal ly mph node enlargement and a small right pleural ef f usion also w ere present , but mediast inosc opy and t horac ent esis w ere negat iv e. B: Comput ed t omography guided perc ut aneous biopsy of right adrenal mass (done in prone posit ion) w as posit iv e f or met ast at ic c arc inoma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1007

7 - Lung Det ec t ion of unsuspec t ed ext rat horac ic spread of bronc hogenic c arc inoma by F DG PET also c an dramat ic ally alt er pat ient management . T he likelihood of det ec t ing suc h met ast ases inc reases in pat ient s w it h loc ally adv anc ed

disease, w hic h may already hav e been doc ument ed on CT . F DG PET is v aluable in det ec t ing bone met ast ases; it is less v aluable in depic t ing c erebral met ast ases t han MRI (or CT ). As w it h ly mph node disease, a posit iv e PET st udy c annot be ac c ept ed as def init iv e proof of met ast ases as f alse- posit iv es oc c ur. Nev ert heless, t here is no doubt t hat F DG PET c an reduc e t he likelihood of nonc urat iv e or f ut ile surgery in lung c anc er pat ient s, and it is inc reasingly being used in v irt ually all pat ient s c onsidered c andidat es f or surgic al resec t ion. Ancilla ry C omme nts. While st ill in t he inv est igat iv e phase, some pat ient s w it h prov en mediast inal ly mph node met ast ases (mediast inosc opy , mediast inot omy , t ransbronc hial needle aspirat ion) may undergo induc t ion c hemot herapy , radiat ion t herapy , or bot h. If t here is doc ument ed regression of disease (e.g., by CT , PET , or mediast inosc opy ), subsequent c omplet e surgic al resec t ion of t he t umor may be at t empt ed (107). Preliminary result s w it h t his c ombinat ion t herapy show improv ement in t he disease- f ree period and some inc reased surv iv al. T hose pat ient s w it h persist ent N2 disease af t er t his neoadjuv ant t herapy are not c andidat es f or surgery . T he ev aluat ion of a pat ient w it h know n or suspec t ed bronc hogenic c arc inoma requires t he det ec t ion and c harac t erizat ion of lesions inv olv ing t he lungs, hila, mediast inum, pleura, c hest w all, and upper abdomen. CT is t he most adv ant ageous radiologic t ec hnique f or ev aluat ing t hese regions simult aneously . St udies hav e f ailed t o demonst rat e any c onsist ent superiorit y of MRI ov er CT in t he assessment of t he primary t umor, det ec t ion of direc t mediast inal ext ension, or t he rec ognit ion of ly mph node met ast asis (335,410,631). In most inst anc es, MRI simply rec apit ulat es t he f indings of CT . Whereas MRI has some t heoret ic al and real adv ant ages (e.g., direc t mult iplanar imaging c apabilit y , av oidanc e of iodinat ed int rav enous c ont rast agent s), t hese are out w eighed by c onsiderat ions suc h as av ailabilit y , c ost , and examinat ion t ime. CT remains t he init ial t omographic examinat ion of c hoic e, w it h MRI assuming a sec ondary problem- solv ing role in pat ient s in w hom CT is inc onc lusiv e or a more primary role w hen iodinat ed c ont rast media is c ont raindic at ed (F ig. 7- 58). On oc c asion MRI may be helpf ul in det ermining t he nat ure of an adrenal mass. Alt hough MRI may be superior t o CT in det ec t ing c hest w all inv asion by bronc hogenic c arc inoma, t his is generally not

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1008

7 - Lung a c rit ic al st aging issue, exc ept perhaps in some selec t ed superior sulc us t umors (see F ig. 7- 45). CT may prov ide unique inf ormat ion in spec if ic c linic al sit uat ions relat ed t o

bronc hogenic c arc inoma. An oc c ult primary t umor may be det ec t ed, somet imes in a pat ient w it h a posit iv e sput um c y t ologic examinat ion or w it h a paraneoplast ic sy ndrome, and no lesion apparent on c hest radiography or f iberopt ic bronc hosc opy . T hese c arc inomas are f requent ly sit uat ed in areas poorly assessed by st andard radiography , suc h as t he lung apic es, or t he paramediast inal and juxt adiaphragmat ic regions. Analogous t o c onv ent ional radiography , lung c arc inomas may be missed on a c hest CT examinat ion (200,643,644).

F igure 7- 58 Magnet ic resonanc e image in pat ient w it h elev at ed c reat inine demonst rat es a large right upper lobe c arc inoma (CA) inv ading t he mediast inum and t he right pulmonary art ery (P).

Bronc hioloalv eolar c ell c arc inoma represent s a subgroup of adenoc arc inoma, w it h ov erlapping f eat ures of t en present in t he same nodule/mass (17,280,308,326,601,657,666) T he link w it h smoking as a predisposing c ause is w eakest w it h t his t y pe of c arc inoma, w hic h also may be assoc iat ed w it h c hronic int erst it ial pulmonary f ibrosis. T hese t umors arise f rom t he t y pe II pneumoc y t es lining t he alv eolar w alls and grow by spreading along t he f ramew ork of t he normal parenc hy ma, w it hout assoc iat ed dest ruc t ion. T hey may present as a solit ary nodule, f oc al c onsolidat ion or dif f use disease. T he c onsolidat iv e f orm may be segment al or lobar, mimic king pneumonia. If a large amount of muc in is present , t he c onsolidat ion w ill appear of relat iv ely low

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1009

7 - Lung at t enuat ion on CT , and on post c ont rast sc ans, t he v essels st andout w it hin t he c onsolidat ion (CT angiogram sign). CT may be v aluable in separat ing t he solit ary f orm of bronc hioloalv eolar c ell c arc inoma f rom t he dif f use v ariet y , t heref ore c hanging t he c at egorizat ion and t herapeut ic approac h (F igs. 7- 59 and 7- 60). As not ed, w hen planning radiat ion t herapy , c ont rast - enhanc ed MDCT c an be helpf ul in dist inguishing a c ent ral endobronc hial mass f rom more dist al

c ollapsed or c onsolidat ed lung (see F igs. 7- 33 and 7- 37). Similarly PET /CT may hav e a v aluable role in t ailoring radiat ion port als and F DG PET may be more benef ic ial t han CT in P.460 quic kly det ermining t reat ment response. Subst ant ial residual F DG ac t iv it y is a relat iv ely poor prognost ic sign af t er t reat ment .

F igure 7- 59 Solit ary bronc hoalv eolar c ell c arc inomas. A: Comput ed t omography demonst rat es an ill- def ined, mainly ground- glass opac it y (ar r ow s)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1010

7 - Lung in t he right upper lobe. B: In anot her pat ient , c omput ed t omography demonst rat es a small area of c onsolidat ion c ont aining luc ent c y st ic areas (pseudoc av it at ion) in t he superior segment of t he right low er lobe (ar r ow s).

C : In anot her pat ient , c omput ed t omography show s a het erogeneous region of ground- glass opac if ic at ion, some sof t t issue at t enuat ion zones of c onsolidat ion, and c y st ic regions (pseudoc av it at ion). T he surgic al resec t ion spec imen show ed some regions of w ell dif f erent iat ed adenoc arc inoma w it hin t he predominat ely bronc hoalv eolar c ell c arc inoma.

CT may inf luenc e t reat ment and be of some prognost ic v alue in pat ient s w it h undif f erent iat ed small (oat ) c ell c arc inoma (193,385). Det erminat ion of disease ext ent may help in t he dec ision about w het her t o use adjuv ant radiat ion t herapy and t o t ailor port als. Init ial peric ardial or abdominal (liv er, adrenals, ly mph nodes) inv olv ement is an espec ially poor prognost ic indic at or (see F ig. 7- 56). CT is more sensit iv e t han plain c hest radiography in det ec t ing rec urrent bronc hogenic c arc inoma, part ic ularly in mediast inal ly mph nodes or in t he post pneumonec t omy spac e (165,460), and may explain some post operat iv e problems (551). Wit h large t umors at present at ion, t here is a great er risk of loc al rec urrenc e (248). Wedge resec t ions may also leav e residual t umor in ly mphat ic s or ly mph nodes, inc reasing t he inc idenc e of loc al rec urrenc e. And among pat ient s t hat surv iv e lung c anc er, t here is a 2.5% annual risk of dev eloping a sec ond primary lung c arc inoma (325), perhaps w arrant ing some rout ine f ollow - up sc anning.

Lung Cancer Screening T he purpose of any sc reening t est is t o prev ent , by means of earlier det ec t ion, t he dev elopment of sy mpt omat ic adv anc ed disease and it s adv erse ef f ec t s (432). As already not ed, bronc hogenic c arc inoma is t he leading c ause of c anc er deat h in bot h men and w omen in t he Unit ed St at es, w here P.461 approximat ely 25% of t he populat ion are smokers or f ormer smokers. T he poor ov erall surv iv al f rom bronc hogenic c arc inoma (15%) relat es t o many pat ient s hav ing adv anc ed regional disease or dist ant spread at t he t ime of present at ion. It w ould be desirable t o ident if y more indiv iduals w it h early st age lung c anc er in an at t empt t o dec rease morbidit y /mort alit y f rom t his disease.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1011

7 - Lung

F igure 7- 60 Mult ic ent ric bronc hoalv eolar c ell c arc inomas. A, B: Selec t ed c ephaloc audal c omput ed t omography images demonst rat e bilat eral ill- def ined nodules (ar r ow s), some w it h c ent ral luc enc ies (pseudoc av it at ion). C : Comput ed t omography guided perc ut aneous needle biopsy est ablishes t he diagnosis. D: In anot her pat ient , c omput ed t omography show s relat iv ely large areas of c onsolidat ion w it h air bronc hograms (pneumonic f orm of disease) in bot h low er lobes.

Prev ious sc reening t rials w it h plain c hest radiography and/or sput um c y t ology f ailed t o show a mort alit y benef it . Subsequent public healt h endeav ors hav e emphasized t he prev ent ion of smoking sinc e at least 90% of lung c anc ers are smoking- relat ed. Early ent husiasm w it h using CT sc reening w as engendered by t he not able number of st age I c anc ers (about 5% t o 6%) det ec t ed in pat ient s w it h emphy sema w ho w ere being c onsidered f or lung t ransplant at ion or lung v olume reduc t ion surgery (527). Mult iple st udies hav e doc ument ed t hat spiral CT is c learly superior t o c hest radiography in t he det ec t ion of small lung c arc inomas. Sev eral init ial sc reening st udies w ere enc ouraging, of t ent imes doubling t he number of lung c anc ers det ec t ed in st age I (116,230,260,337,429,657,658). F alse–posit iv e nodules, how ev er, w ere

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1012

7 - Lung not ed t o be v ery c ommon on t he baseline (prev alenc e) st udies, at least 50% in some geographic areas, but less f requent on f ollow - up (inc idenc e) examinat ions. Det ermining w het her suc h nodules are malignant generally requires a minimum of one more CT examinat ion P.462 P.463 t o asc ert ain f or possible grow t h. And in some sc reening st udies, almost 80% of sc reened indiv iduals hav e f urt her t est ing rec ommended f or observ ed abnormalit ies, inc luding pot ent ially serious anc illary f indings (suc h as a mediast inal mass or liv er or renal lesion).

F igure 7- 61 Nat ional Lung Sc reening T rial det ec t ed rapidly grow ing lung c arc inoma. A: Init ial low dose c omput ed t omography demonst rat es a w ellc irc umsc ribed 7- mm diamet er nodule (ar r ow ) in t he lef t upper lobe. B: F ollow up low dose c omput ed t omography 6 mont hs lat er show s a dramat ic inc rease in size t o 2.9 c m in diamet er. Resec t ed spec imen disc losed poorly dif f erent iat ed adenoc arc inoma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1013

7 - Lung

F igure 7- 62 Nat ional Lung Sc reening T rial det ec t ed lung c arc inomas. A: Low dose c omput ed t omography demonst rat es a spic ulat ed 11- mm nodule (ar r ow ) in t he lef t upper lobe (adenoc arc inoma). B: In anot her pat ient , low dose c omput ed t omography show s a mainly ground- glass 19- mm nodular opac it y , w it h mult iple bubble luc enc ies, espec ially in t he c ent er (pseudoc av it at ion) in t he right upper lobe (bronc hoalv eolar c ell c arc inoma).

All sc reening CT lung c anc er examinat ions use dec reased milliamps and of t en peak kilov olt age t o diminish t he radiat ion dose t o t he pat ient (63). Nodules not c ont aining benign c alc if ic at ions ident if ied on CT sc reening should be c lassif ied depending on t heir size, shape, and margins. F or small nodules (4 t o 10 mm), a f ollow - up CT examinat ion is almost alw ay s rec ommended. Based on a 3- y ear experienc e w it h t he Nat ional Lung Sc reening T rial (NLST ) (234), t his aut hor generally rec ommends 12 mont hs f or lesions 4 t o 6 mm in great est diamet er (less t han 4 mm nodules are c onsidered negat iv e). Wit h nodules 7 t o 9 mm in great est diamet er, a 6- mont h f ollow - up is usually rec ommended (F ig. 7- 61). T he c harac t erist ic s (margins) of t he nodule f ac t or int o t his rec ommendat ion rec ognizing t hat surrounding emphy sema may make some diagnost ic c rit eria unreliable (362). Solid nodules w it h spic ulat ed margins larger t han 8 mm in diamet er are c onsidered highly suspic ious, as are ground glass nodular opac it ies larger t han 10 in diamet er (F ig. 7- 62), alt hough t he v ast majorit y of t he lat t er are not bronc hoalv eolar c arc inomas (F ig. 7- 63). Also, a short er f ollow - up int erv al generally is rec ommended f or nodules disc ov ered during t he inc idenc e st udies (prov ided t hey are t ruly new and not simply prev iously ov erlooked). Wit h larger lesions (10 mm or great er), PET imaging, perc ut aneous biopsy or ev en resec t ion may be suggest ed, along w it h t he opt ion of a 3- mont h f ollow - up CT examinat ion (perhaps af t er broad

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1014

7 - Lung spec t rum ant ibiot ic t reat ment ). It is rarely possible on a single sc reening

examinat ion alone t o dogmat ic ally st at e t hat a lung c anc er is present . But f or lesions t hat def init ely grow , remov al/biopsy needs t o be c onsidered. Measuring t he grow t h of nodules is not simple, espec ially w hen only 2D CT images are used (515). F or a nodule t o double in v olume, [4/3 II (d/2) 3], d must inc rease by 25%, w hic h is dif f ic ult t o disc ern w it h small nodules. Volumet ric nodule rec onst ruc t ions prov ide more reliable ev idenc e of lesion grow t h (301), but ev en t hey c an v ary relat ed t o t he phase of respirat ion, and t hey inc rease t he t ime and c ost of sc reening st udies. Ev en st abilit y of a nodular opac it y f or 2 y ears is not absolut e c rit erion of a benign lesion as some ground- glass opac it ies or irregular sc ar- like lesions due t o prov en bronc hoalv eolar c ell c arc inoma may not c onv inc ingly display grow t h in t his t ime period. How ev er, t hese lat t er lesions are unlikely t o hav e a negat iv e c linic al impac t in almost all pat ient s in w hom t he diagnosis is delay ed. As prev iously not ed, lung c anc ers c an be missed on CT examinat ions by c aref ul, c onsc ient ious radiologist s (259,336). Generally , t hey are smaller t han 1 c m in diamet er, and ov erlapped/obsc ured by surrounding st ruc t ures, usually v essels, or by adjac ent sc arring. Most nodules missed on init ial prev alenc e sc ans are det ec t ed on subsequent inc idenc e examinat ions, st ill usually at st age I. Aut omat ed c omput er programs generally c an inc rease t he P.464 det ec t ion of suc h missed nodules, espec ially t hose more c ent ral in t he pulmonary parenc hy ma, but at t he “ c ost ” of ident if y ing ot her f alse–posit iv e nodules (528).

F igure 7- 63 Inf lammat ory ground- glass opac it y . A: Nat ional Lung Sc reening T rial low dose c omput ed t omography demonst rat es a f oc al area of ground-

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1015

7 - Lung glass opac if ic at ion (ar r ow s) in t he right low er lobe. B: F ollow - up low dose c omput ed t omography 6 mont hs lat er demonst rat es c omplet e int erv al resolut ion of t he opac it y .

No c lear guidelines exist as t o w ho should be sc reened f or lung c anc er or at w hat int erv als. At our inst it ut ion, w e sc reen indiv iduals only as part of t he randomized NLST (subst ant ial smokers age 55 t o 74 y ears; an init ial baseline f ollow ed up w it h a minimum of 2 subsequent y early st udies; a 6- mont h int erv al healt h rev iew inc luding an assessment of t heir qualit y of lif e is also c onduc t ed). Alt hough suc h y early sc reening might be reasonable, some aggressiv e c arc inomas hav e bec ome manif est bet w een suc h st udies (F igs. 764 and 7- 65). T he high f alse–posit iv e rat e has led t o inc reased pat ient , and somet imes ref erring c linic ian, anxiet y . Asy mpt omat ic indiv iduals bec ome pat ient s w hen inf ormed t hey hav e a lung nodule. Addit ional c ost s, bey ond sc reening, are generat ed, f or f ollow - up CT examinat ions, alt ernat iv e t est s suc h as PET imaging, et c . Inc ident al f indings, many of no c linic al relev anc e, also somet imes require f ollow - up/ref erral, f urt her inc reasing c ost . Rarely , benign nodules are resec t ed (F ig. 7- 66), in some c ases bec ause t hey hav e grow n (F ig. 7- 67).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1016

7 - Lung

F igure 7- 64 Aggressiv e int erv al c arc inoma. A: Init ial low - dose NLST c omput ed t omography is normal. B: F ollow - up low - dose c omput ed t omography one y ear lat er demonst rat es dev elopment of new irregular 2- c m nodular opac it y in ant erior basal segment of t he lef t low er lobe. T he lef t hilum has inc reased in size in t he int erv al. C : Subsequent c ont rast - enhanc ed diagnost ic c omput ed t omography demonst rat es enlarged lef t hilar ly mph nodes. Pat hologic diagnosis w as poorly dif f erent iat ed adenoc arc inoma.

Pat ient s need t o be inf ormed t hat a negat iv e sc reening CT examinat ion does not prec lude t he subsequent dev elopment of lung c anc er, somet imes ev en bet w een sc reening int erv als, and as ment ioned, some lung c anc ers w ill not be det ec t ed on CT , espec ially c ent ral ones, inc luding t hose arising in t he bronc hial lumens. F or t he lat t er, sput um c y t ology or f luoresc enc e bronc hosc opy may be alt ernat iv e sc reening t ec hniques. Appropriat e personnel need t o be av ailable t o c ounsel and ev aluat e a pat ient w it h a posit iv e sc reening t est (339). At our medic al c ent er, a biw eekly SPIN (solit ary pulmonary indet erminat e nodule) c linic is c onduc t ed, w it h a nurse c oordinat or,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1017

7 - Lung a t horac ic surgeon, a pulmonologist , and a radiologist all present t o of f er rec ommendat ions.

F igure 7- 65 A: Init ial NLST low - dose c omput ed t omography demonst rat es a 17- mm mixed sof t t issue/ground- glass at t enuat ion nodular opac it y (ar r ow ) in t he lef t low er lobe. Surgic al resec t ion disc losed a st age I mixed w elldif f erent iat ed adenoc arc inoma/bronc hoalv eolar c ell c arc inoma, a t heoret ic al c ure. B, C : Cephaloc audal c omput ed t omography images f rom a diagnost ic c omput ed t omography perf ormed 20 mont hs lat er (8 mont hs af t er normal post operat iv e c omput ed t omography ), bec ause of w eight loss, demonst rat es a new nodule in t he lef t upper lobe (ar r ow ), plus enlarged ly mph node mass (n) in t he aort opulmonary w indow . A mildly enlarged subc arinal ly mph node also is present . Subsequent perc ut aneous needle aspirat ion of t he large node disc losed small c ell undif f erent iat ed c arc inoma.

P.465

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1018

7 - Lung All c urrent published lung c anc er CT sc reening st udies are non- randomized, lac k a c ont rol group, and suf f er f rom inherent sc reening biases (e.g., lead t ime, lengt h t ime, ov erdiagnosis) (54,450,571,594). Improv ed surv iv al is merely post ulat ed (based upon f inding a preponderanc e of st age I lesions), not prov en (rec ognizing t his is t rue f or ot her w idespread medic al sc reening t est s, inc luding prost at e spec if ic ant igen [PSA] f or prost at e c arc inoma). It remains undet ermined w het her t he det ec t ion of more early st age c arc inomas

represent s a t rue st age shif t or merely ov erdiagnosis. T here c ert ainly c an be a negat iv e impac t upon t he qualit y of lif e, and ev en mort alit y , f rom int erv ent ions t hat do not af f ec t ov erall morbidit y /mort alit y . Ev en if t his t est pot ent ially c an sav e liv es, it s c ost is not know n, and a dec ision about w ho should pay f or t he examinat ion (e.g., priv at e healt h plans, t he gov ernment , t he pat ient w ho smoked c igaret t es) has not y et been addressed. Current ly , no prof essional healt h- c are organizat ion rec ommends CT sc reening f or lung c anc er.

Pulmonary Collapse T he pat t erns of pulmonary c ollapse seen on t he st andard c hest radiograph hav e been w ell desc ribed. How ev er, t he appearanc e may be c onf using, espec ially if sc arring or adhesions exist bet w een t he lung and adjac ent pleura. CT is of t en helpf ul in c larif y ing t hat t he plain radiographic f ilm f indings are sec ondary t o c ollapse (166,412,417,418,480,653), and f urt hermore may suggest t he c ause and det ermine t he ext ent of any obst ruc t ing mass (see F igs. 7- 11, 7- 12, 7- 13; F ig. 7- 68). T he underly ing mediast inum is not obsc ured by t he c ollapsed lung on CT and c an be easily ev aluat ed P.466 f or c oexist ent ly mphadenopat hy or direc t inv asion by a bronc hial neoplasm. Int rav enous c ont rast administ rat ion generally is helpf ul in delineat ing a proximal obst ruc t ing t umor and separat ing it f rom dist al at elec t at ic lung as w ell as f rom adjac ent mediast inal st ruc t ures. Collapsed dist al lung usually enhanc es t o a great er degree t han t he proximal neoplasm. How ev er, in some c ases, separat ion may not be possible, despit e opt imal c ont rast enhanc ement t ec hnique. If t he c ollapsed lung c ont ains a large amount of w at er (e.g., drow ned lung dist al t o t umor) it may not enhanc e more t han t he t umor (F ig. 7- 69). In addit ion, if t he blood supply t o t he c ollapsed lobe is obst ruc t ed P.467

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1019

7 - Lung or if t he t umor is v asc ular, t here may not be suf f ic ient dif f erenc es in enhanc ement pat t ern t o allow separat ion.

F igure 7- 66 Granulomat ous inf ec t ion. A: NLST low - dose c omput ed t omography show s a spic ulat ed 12 mm nodule in t he lef t upper lobe. B: F usion F DG- PET /c omput ed t omography image demonst rat ed an SUV in t he nodule of 5.9, c onsist ent w it h an aggressiv e neoplasm. T he resec t ion spec imen disc losed m y c obac t er ium xenopi.

F igure 7- 67 Benign grow ing nodule. A: Init ial NLST low - dose c omput ed t omography demonst rat ed a v ery w ell- c irc umsc ribed homogeneous 11- mm nodule (ar r ow ) in t he right low er lobe, int erpret ed as likely benign. B: F ollow up low - dose c omput ed t omography 1 y ear lat er show s t hat t he nodule has grow n t o 15 mm in diamet er. T he nodule w as resec t ed and pat hologic ally w as an amy loidoma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1020

7 - Lung General Observations Bot h t he direc t (f issural displac ement , dec reased size of hemit horax, v asc ular/bronc hial c row ding) and indirec t (mediast inal shif t , hilar displac ement , hy poaerat ion, c ompensat ory hy peraerat ion, elev at ion of

hemidiaphragm) signs of c ollapse seen on plain c hest radiographs (474) c an be applied t o CT (166). T his bec omes import ant so as not t o c onf use t he CT f indings w it h a lung mass. T he lobes lose v olume w hile generally maint aining c ont ac t w it h t he c hest P.468 w all peripherally and t he hilum c ent rally , result ing in a w edge shape on CT , w hic h is not alw ay s apparent on c onv ent ional radiography . As c ompensat ion f or t he spac e f ormerly oc c upied by an expanded lobe, an ipsilat eral adjac ent lobe may ov erinf lat e, appearing more luc ent and oligemic . Alt hough most observ at ions c an be made on a st andard CT examinat ion (5- t o 7- mm- t hic k sec t ions), rec onst ruc t ion of addit ional t hin sec t ions (1 mm) may be helpf ul in ev aluat ing spec if ic lobar or segment al bronc hi f or an obst ruc t ing mass.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1021

7 - Lung

F igure 7- 68 Lef t upper lobe c ollapse. A: On a post c ont rast c omput ed t omography , t he c ollapsed lobe appears as a t riangular, enhanc ing st ruc t ure, sharply marginat ed lat erally by t he major f issure (ar r ow s). T he relat iv ely low at t enuat ion t ubular st ruc t ures (ar r ow head) in t he c ollapsed lobe represent dilat ed muc us f illed bronc hi.B: On a more c audal image, a small enhanc ing mass (ar r ow heads) is seen oc c luding t he lef t upper lobe bronc hus. Bronc hosc opic biopsy disc losed a w ell dif f erent iat ed neuroendoc rine c arc inoma (c arc inoid t umor). C : In anot her pat ient , a relat iv ely low at t enuat ion c ent ral t umor mass (ar r ow heads) is seen obst ruc t ing t he lef t upper lobe bronc hus. Bronc hosc opy rev ealed squamous c ell c arc inoma. T he mildly enlarged aort opulmonary w indow nodes (ar r ow ) w ere reac t iv e on surgic al resec t ion. D: In anot her pat ient , a large c ent ral mass (ar r ow heads) oc c ludes t he lef t upper lobe bronc hus, w it h great er enhanc ement of t he more dist al at elec t at ic upper lobe (l). Marked c onc omit ant subc arinal ly mph node enlargement (n) is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1022

7 - Lung present . Spec imens f rom bronc hosc opy and t ransbronc hial needle biopsy of t he subc arinal mass disc losed poorly dif f erent iat ed squamous c ell c arc inoma.

Left Upper Lobe Collapse T he lef t upper lobe (LUL) c ollapses predominant ly in an ant erosuperior direc t ion against t he ant erior c hest w all. Superior migrat ion of t he lung is limit ed somew hat by t he lef t pulmonary art ery passing ov er t he LUL bronc hus. As a result , t he superior segment of t he lef t low er lobe f requent ly hy perexpands bet w een t he c ollapsed LUL and aort ic arc h, t ow ard t he lef t lung apex, ac c ount ing f or t he periaort ic luc enc y seen on t he plain c hest radiograph. On CT , t he at elec t at ic LUL appears as a t riangular or V- shaped sof t t issue densit y st ruc t ure t hat abut s t he c hest w all ant erolat erally w it h t he apex of t he V merging w it h t he pulmonary hilum (see F ig. 7- 68). As t he c ollapse inc reases t here is less c ont ac t of t he LUL w it h t he lat eral c hest w all. T he c ollapsed lobe is bordered medially by t he mediast inum and post eriorly by t he major f issure, w hic h is displac ed ant eriorly . Alt hough t he lobe is usually of homogeneous at t enuat ion, some c row ded air- f illed bronc hi may be seen. Sec ondary signs of c ollapse t hat are v isible inc lude elev at ion of t he lef t hilum, w it h f oreshort ening of t he aort opulmonary w indow , along w it h mediast inal displac ement , usually ac c ompanied by herniat ion of t he right lung ant eriorly . Wit h elev at ion of t he lef t hilum t he LUL bronc hus, w hic h is normally low er t han t he right , may be seen at approximat ely t he same lev el. Moreov er, t he lef t low er lobe bronc hus may mov e ant erolat erally . If t he elev at ed lef t pulmonary art ery is imaged lat eral t o t he aort ic arc h, it may simulat e ly mphadenopat hy . Dec reased size of t he lef t hemit horax also is apparent and is of t en muc h more st riking on CT t han on t he c hest radiograph. In t he absenc e of a large proximal obst ruc t ing lesion, t he c ollapsed lobe should t aper smoot hly t ow ard t he hilum. If t he obst ruc t ing mass (e.g., bronc hogenic c arc inoma, ly mphadenopat hy ) is large enough, a c ont our bulge may be seen (see F ig. 7- 68 C, D). T he w edge of lung w ill be seen t o w iden f oc ally rat her t han t aper as it ext ends t o t he hilum. T his is t he CT equiv alent of t he S sign of Golden and may be more apparent t han on plain c hest radiographs. Alt hough t he dist inc t ion bet w een benign and malignant neoplasms c an only be made hist ologic ally , in some c ases CT c an c onf ident ly ident if y a benign c ause of obst ruc t ion (e.g., bronc holit hiasis).

Right Upper Lobe Collapse

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1023

7 - Lung T he pat t ern of right upper lobe (RUL) c ollapse is dif f erent t han t hat of LUL c ollapse bec ause t he RUL is smaller t han t he LUL (w hic h inc orporat es t he lingular div ision) and has t w o f issural borders (minor and major f issures). F urt hermore, t he right main st em bronc hus is more apt t o shif t as a result of lobar c ollapse bec ause it is not f ixed at t he hilum by t he right pulmonary art ery . T hese dif f erenc es result in t he RUL c ollapsing superiorly and medially rat her t han predominant ly ant eriorly as in LUL c ollapse. On CT , t he c ollapsed RUL is seen as a sharply def ined t riangular densit y bordered by t he minor

f issure lat erally and t he major f issure post eriorly (F ig. 7- 70). T he minor f issure has a st raight border, w hereas t he major f issure may hav e a st raight , c onc av e, or c onv ex border. T here is elev at ion of t he right hilum and t he right pulmonary art ery may be seen at a higher lev el t han normal. In addit ion, t he right main st em bronc hus may rot at e ant eriorly . Hy perexpansion of t he middle and low er lobes also oc c urs. T he superior segment of t he low er lobe may ext end bet w een t he mediast inum and medial border of t he c ollapsed RUL, but t his is a less c ommon f inding t han w it h c ollapse of t he LUL. Moreov er, ant erior lung herniat ion is less c ommon, probably bec ause of t he smaller size of t he RUL.

Right Middle Lobe Collapse Wit h c ollapse of t he right middle lobe (RML), t he minor f issure and low er half of t he major f issure mov e c lose t oget her. On CT sc ans, t he c ollapsed lobe is t riangular or t rapezoidal, and is demarc at ed by t he minor f issure ant eriorly P.469 and major f issure post eriorly (F ig. 7- 71). T he int erf ac e bet w een t he middle and upper lobe is f requent ly less dist inc t t han t hat bet w een t he middle and low er lobe bec ause t he minor f issure is more parallel t o t he sc anning plane. T he c ollapsed RML dec reases it s c ont ac t w it h t he lat eral c hest w all but maint ains it s c ont ac t w it h t he ant erior c hest w all on more c audal images. Bec ause of t he small v olume of t he RML, usually t here is no signif ic ant mediast inal shif t , c ompensat ory hy perinf lat ion, or dec reased v olume of t he hemit horax. Segment al c ollapse, w hic h may be c onf using on plain c hest radiographs, is easily det ec t ed on CT by f ollow ing t he c ourse of t he middle lobe bronc hus as it bif urc at es int o medial and lat eral segment al bronc hi. T he medial segment abut s t he heart and ant erior c hest w all, w hereas t he lat eral segment ext ends post erior t o t he hilum and does not c ont ac t t he heart .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1024

7 - Lung

F igure 7- 69 “ Drow ned” obst ruc t ed lef t upper lobe. Post c ont rast c omput ed t omography show s a c onsolidat ed lef t upper lobe w it hout not able v olume loss. Alt hough t he lef t upper lobe bronc hus is not ed t o be c omplet ely oc c luded, t he size of t he c ent ral mass c annot be det ermined. An enlarged subc arinal ly mph node (ar r ow ) is present . Mediast inosc opic biopsy of enlarged pret rac heal ly mph nodes seen on more c ephalad c omput ed t omography images disc losed poorly dif f erent iat ed squamous c ell c arc inoma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1025

7 - Lung

F igure 7- 70 Right upper lobe c ollapse. A: On c omput ed t omography , t he c ollapsed lobe appears as a t riangular, enhanc ing st ruc t ure, sharply marginat ed lat erally by t he minor f issure (solid ar r ow s) and post eriorly by t he major f issure (open ar r ow ). B: On a more c audal image, t he obst ruc t ion (ar r ow ) of t he lobar bronc hus is demonst rat ed. C : Ev en more c audal, t he c ollapsed lobe is f lat t ened against t he mediast inum.

Lower Lobe Collapse T he pat t ern of c ollapse is similar f or bot h low er lobes, w hic h c ollapse c audally , post eriorly , and medially t ow ard t he spine. On CT , t he c ollapsed low er lobe appears as a w edged- shaped sof t t issue at t enuat ion st ruc t ure adjac ent t o t he spine (F igs. 7- 72 and 7- 73). T he major f issure, w hic h f orms t he lat eral border of t he lobe, is displac ed

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1026

7 - Lung P.470 post eriorly . T he upper border of t he c ollapsed lobe is usually c onc av e (in t he absenc e of a large c ent ral mass) w hereas t he low er border may be st raight , c onc av e, or c onv ex. T he v ary ing c onf igurat ions relat es t o t he ext ent of c ollapse, presenc e or absenc e of a c ent ral mass, degree of dist al pneumonia, and t he anat omy of t he inf erior pulmonary ligament . If t he at t ac hment of t he pulmonary ligament t o t he hemidiaphragm is inc omplet e, t he low er lobe may c ollapse more c omplet ely adjac ent t o t he spine and hav e a rounded c audal appearanc e (F ig. 7- 74), espec ially on plain radiographs. Sec ondary signs of c ollapse inc lude inf erior and medial displac ement of t he hilum, post eromedial displac ement of t he low er lobe bronc hus, ipsilat eral mediast inal shif t , hemidiaphragm elev at ion, c ompensat ory hy perinf lat ion, and dec reased size of t he hemit horax.

F igure 7- 71 Middle lobe c ollapse. Collapsed lobe seen as a w edge- shaped st ruc t ure, bordered by t he minor (long ar r ow s) and major (shor t ar r ow s) f issures. Air is seen in t he segment ed bronc hi in t he c ollapsed lobe, w hic h w as due t o bronc holit hiasis.

Role of Magnetic Resonance Imaging in Pulmonary Collapse

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1027

7 - Lung In most pat ient s MRI prov ides c omparable inf ormat ion t o CT w it h respec t t o ident if y ing lobar c ollapse and ev aluat ing t he underly ing mediast inum (611). Separat ion of t umor f rom dist al c ollapsed lung is of t en possible using a T 2w eight ed pulse sequenc e, on w hic h t he c ollapsed lung is usually higher in signal int ensit y t han t he more proximal t umor, ref lec t ing t he higher w at er c ont ent of t he c ollapsed lung (59,232). Bec ause t he w at er c ont ent of t umors and c ollapsed lobes v ary , dist inc t ion is not alw ay s possible. MRI is inf erior t o CT in delineat ing bronc hial anat omy , and bronc hial narrow ing may be ov erest imat ed bec ause of respirat ory mot ion and lesser spat ial resolut ion.

Compressive Atelectasis Compressiv e (or passiv e) at elec t asis most f requent ly oc c urs sec ondary t o f luid or air w it hin t he pleural spac e. Whereas a large pleural ef f usion c an obsc ure parenc hy mal disease on t he plain c hest radiograph, CT c an dist inguish P.471 at elec t at ic lung underly ing t he pleural ef f usion (F ig. 7- 75) (444). If t he bronc hus is pat ent and air bronc hograms are seen t hroughout t he lobe, proximal obst ruc t ion is unlikely . T he dist inc t ion bet w een t he low er at t enuat ion pleural f luid and relat iv ely higher densit y c ollapsed lung c an be apprec iat ed on non–c ont rast - enhanc ed images, but t he dif f erenc e is ac c ent uat ed by int rav enous c ont rast administ rat ion. In pat ient s w it h malignant pleural disease, t he lung may be c ompressed by t umor masses as w ell as by pleural f luid. Neoplasm w it hin t he pleural spac e also is more easily seen f ollow ing int rav enous c ont rast administ rat ion (see F ig. 7- 75).

F igure 7- 72 Lef t low er lobe c ollapse. A, B: Sequent ial c ephaloc audal c omput ed t omography images show a c ent ral c ont our def orming squamous c ell

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1028

7 - Lung c arc inoma (w hit e ar r ow heads) c omplet ely obst ruc t ing t he lef t low er lobe bronc hus (blac k ar r ow ). T ubular muc us- f illed bronc hi (blac k ar r ow head) are seen dist al t o t he t umor. Part ially nec rot ic enlarged subc arinal nodes

c ont aining met ast ases (w hit e ar r ow ) also present . Not e t he v olume loss in t he lef t hemit horax.

F igure 7- 73 Combined right middle and low er lobe at elec t asis. A, B: Selec t ed c ephaloc audal c omput ed t omography images demonst rat e a c ollapsed middle (m) and right low er lobe (l). T he c ause is muc us plugging (ar r ow ) in t he bronc hus int ermedius. A small right pleural ef f usion (e) is seen.

F igure 7- 74 Low er lobe at elec t asis. Post c ont rast c omput ed t omography demonst rat es marked enhanc ement of t he c ollapsed lef t low er lobe (ar r ow heads) and post erior basal segment of t he right low er lobe (ar r ow ) in a post abdominal surgery pat ient suspec t ed of hav ing pulmonary embolism.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1029

7 - Lung

T he pat t erns of c ompressiv e at elec t asis sec ondary t o a pleural ef f usion relat e in part t o t he size of t he pleural ef f usion. Wit h small ef f usions, CT may demonst rat e only subsegment al c ollapse of a low er lobe, seen ant erior t o t he pleural ef f usion. T he major f issure is v isible f urt her ant erior t o t he remainder of t he aerat ed low er lobe. As t he pleural ef f usion inc reases in size, most of t he low er lobe is c ollapsed, and t he major f issure is no longer v isible as a disc ret e st ruc t ure. Wit h larger ef f usions, f luid c an be seen ext ending int o t he major f issure ant erior t o t he c ollapsed lobe. T he inf erior pulmonary ligament c an be ident if ied t ransf ixing t he medial border of t he low er lobe t o t he mediast inum and div iding t he medial pleural spac e int o ant erior and post erior c ompart ment s (142,526).

Cicatrization Atelectasis Cic at rizat ion at elec t asis ref ers t o v olume loss sec ondary t o sc arring f rom prev ious inf lammat ory disease (418). Endobronc hial obst ruc t ion is not present . T he degree of v olume loss may be more marked t han in c ases of c ollapse sec ondary t o endobronc hial obst ruc t ion. Assoc iat ed t rac t ion bronc hiec t asis in t he at elec t at ic lobe and pleural t hic kening are f requent ly present . T he usual pat t ern of c ollapse may be alt ered sec ondary t o pleural adhesions and parenc hy mal sc arring. F or example, a c ic at rized RUL may c ollapse more post eriorly w it h post erior rot at ion of t he c arina and RUL bronc hus.

Rounded Atelectasis Rounded at elec t asis is a f orm of nonsegment al peripheral pulmonary c ollapse t hat may mimic a primary lung or pleural neoplasm. T he lesion probably is t he residua of a prev ious exudat iv e pleural ef f usion, w hic h may be c aused by a v ariet y of inf lammat ory proc esses inc luding prior t horac ic P.472 surgery and asbest os exposure (382,613), w it h sy mphy sis of t he v isc eral and pariet al pleura, and result ant inf olding and ent rapment of a peripheral port ion of t he underly ing lung. T his pulmonary pseudot umor, usually about 3 t o 5 c m in diamet er and most c ommonly loc at ed basally and dorsally , espec ially in t he paraspinal region, is c omposed of a sw irl of at elec t at ic parenc hy ma adjac ent t o t hic kened pleura. Alt hough c onv ent ional radiography and t omography may demonst rat e c harac t erist ic f indings, espec ially a c omet - like t ail adjac ent t o t he medial aspec t of t he mass produc ed by pulmonary art eries and bronc hi

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1030

7 - Lung ent ering t he f oc al at elec t at ic lung, CT c an be helpf ul in depic t ing t he f ull

ext ent of t he benign disease proc ess and c onf irming t he diagnosis (F igs. 7- 76, 7- 77, 7- 78) (112). T he CT f indings inc lude (a) a rounded or w edge- shaped mass t hat f orms an ac ut e angle w it h t hic kened pleura, w hic h is immediat ely adjac ent t o t he mass or c onnec t ed by a short f ibrous band; t he pleura is usually t hic kest at it s c ont ac t w it h t he c ont iguous mass, (b) v essels and bronc hi emanat ing f rom t he hilar region, sw irling around and c onv erging in a c urv ilinear f ashion int o t he low er border of t he mass (CT equiv alent of t he c omet t ail sign), (c ) air bronc hograms or indist inc t ness in t he c ent ral port ion of t he mass; t he periphery of t he mass may be more opaque bec ause it represent s t he area of most c omplet e at elec t asis, (d) not able and usually homogeneous c ont rast enhanc ement of t he at elec t at ic lung, (e) adjac ent parac ic at ric ial hy perinf lat ed lung, and (f ) v olume loss in t he ipsilat eral hemit horax, inc luding f issural or mediast inal displac ement . Rounded at elec t asis of t en is assoc iat ed w it h a hist ory of asbest os exposure (382). In suc h pat ient s, CT f requent ly demonst rat es pleural plaques or parenc hy mal f ibrosis in P.473 P.474 ot her areas of t he t horax. Rounded at elec t asis usually remains st able on serial radiologic st udies, alt hough v ery slow grow t h or regression may oc c ur. In t he majorit y of c ases, t he CT f indings are so dist inc t iv e t hat f urt her ev aluat ion usually is not nec essary . How ev er, if t he CT f indings are equiv oc al, perc ut aneous needle biopsy of t he mass c an be v aluable f or c larif ic at ion; a spec imen demonst rat ing f ibrosis only solidif ies t he diagnosis. Ot herw ise, radiologic f ollow - up or surgic al resec t ion is required f or indet erminat e lesions.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1031

7 - Lung

F igure 7- 75 Compressiv e at elec t asis sec ondary t o a pleural ef f usion. A: Post c ont rast c omput ed t omography demonst rat es a mildly enhanc ing c ollapsed lef t upper lobe (u), w it h int ac t c ent ral bronc hi. Enhanc ing areas of pleural t hic kening (ar r ow heads) are due t o a malignant mesot helioma. B: More c audal c omput ed t omography image show s t he c ompressed lef t low er lobe (I). C : Ref ormat t ed c oronal c omput ed t omography image show s t he large lef t pleural ef f usion and t he c ollapsed lef t (L) lung.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1032

7 - Lung

F igure 7- 76 Rounded at elec t asis. A, B: Mediast inal and lung w indow set t ings demonst rat e a paraspinal mass (m) in t he lef t low er lobe, w it h v essels (ar r ow s) c onv erging around it s periphery . T he lesion is adjac ent t o t he most marked pleural t hic kening post eriorly in t he lef t hemit horax, relat ed t o prior asbest os exposure. Abundant ext rapleural f at (ar r ow heads), due t o c hronic pleural disease, also is not ed. Similar, but less sev ere c hanges are present in t he right post erior hemit horax. C : High- resolut ion c omput ed t omography t hrough t he same region more graphic ally depic t s t he peripheral sc arring and c onv erging v essels, w it h bronc hi c lust ered near t he apex of t he at elec t at ic lung (open ar r ow ). Some pleural c alc if ic at ion also c an now be seen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1033

7 - Lung

F igure 7- 77 Rounded at elec t asis. Comput ed t omography show s a right paraspinal mass w it h v essels c urv ing around it s lat eral aspec t . T he lesion is adjac ent t o t he most marked pleural t hic kening and c alc if ic at ion, due t o prior asbest os exposure, in t he right hemit horax, w here c onc omit ant v olume loss also c an be not ed. Calc if ied pleural plaques also are present in t he lef t hemit horax.

F igure 7- 78 Rounded at elec t asis equiv alent s. Comput ed t omography show s w edge- shaped opac it ies (ar r ow s) in eac h upper lobe peripherally , adjac ent t o marked pleural t hic kening. Pleural plaques and t hic kening are seen in ot her loc at ions in bot h hemit horac es.

Bronchiectasis

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1034

7 - Lung Bronc hiec t asis, w hic h by def init ion represent s irrev ersible dilat at ion of t he bronc hi, has been c lassif ied pat hologic ally int o t hree f orms, depending on t he sev erit y of t he bronc hial dilat at ion: · Cy lindr ic al (t ubular)—unif orm mild dilat at ion w it h loss of normal t apering. · Var ic ose—great er dilat at ion w it h irregular c aliber due t o areas of expansion and narrow ing. · Cy st ic (sac c ular)—marked dilat at ion w it h peripheral ballooning. T he plain c hest radiographic f indings in bronc hiec t asis are of t en nonspec if ic , unless t he disease is v ery adv anc ed (198). Surrounding inf ilt rat e or f ibrosis,

w hic h may be c ausat iv e (641) as w ell as a sequela, c an obsc ure rec ognit ion of dilat ed, t hic k- w alled bronc hi. In t he past , bronc hography usually w as required f or c onf irmat ion (or exc lusion). Now CT , w hic h is c learly saf er and easier t o perf orm, and c auses no pat ient disc omf ort , is t he imaging t ec hnique of c hoic e t o est ablish t he presenc e and ext ent of bronc hiec t asis (351,372,395,564). While eac h of t he pat hologic t y pes of bronc hiec t asis has a c harac t erist ic appearanc e on CT , t he dif f erent iat ion bet w een t he v arious f orms is muc h less import ant t han t he simple ident if ic at ion of t he disease proc ess it self .

F igure 7- 79 Cy lindric al (t ubular) bronc hiec t asis. A 1.5- mm c ollimat ed c omput ed t omography demonst rat es mild dilat at ion and w all t hic kening in

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1035

7 - Lung c ranioc audally orient ed bronc hi (ar r ow head); c ompare diamet er t o adjac ent pulmonary art ery . Similar c hanges are present in horizont ally orient ed bronc hi (ar r ow s). T his 65- y ear- old w oman has a rare allele f or c y st ic f ibrosis.

Rec ognit ion of t he anat omic c hanges produc ed by bronc hiec t asis, and dist inc t ion f rom t he normal pulmonary parenc hy ma, is best ac hiev ed by obt aining t he CT sc ans w it h narrow c ollimat ion (191,209), now almost alw ay s ac c omplished w it h spiral MDCT . High- resolut ion CT (HRCT ) is suf f ic ient ly sensit iv e and spec if ic t o serv e as bot h t he sc reening and t he def init iv e diagnost ic imaging t ec hnique in pat ient s suspec t ed of hav ing bronc hiec t asis, and it has an ov erall ac c urac y of about 97% (72,262). Normal bronc hi are not v isible on CT in t he most peripheral areas of t he lung, w it hin 2 c m of t he c ost al or parav ert ebral pleura. T he c ardinal sign of bronc hiec t asis is dilat at ion of t he bronc hus, w hic h usually is ac c ompanied by bronc hial w all t hic kening (int ernal diamet er T able of Cont ent s > 8 - Pleura, Chest Wall, and Diaphragm

8 Pleura, Chest Wall, and Diaphragm Da v id S. Gie ra da Ric ha rd M. Slone Pleural, c hest w all, diaphragmat ic , and pulmonary parenc hy mal proc esses c an c ause opac if ic at ion t hat somet imes c annot be disc riminat ed or ev aluat ed separat ely on st andard c hest radiographs. Primary c hest w all abnormalit ies may ev en produc e minimal or no radiographic f indings. Alt hough radiography remains t he init ial and most f requent t horac ic imaging examinat ion, t he superior c ont rast sensit iv it y and c ross- sec t ional imaging f ormat of c omput ed t omography (CT ) c an be v ery v aluable in det ec t ing and c harac t erizing diseases of t he pleura, c hest w all, and diaphragm. CT allow s simult aneous and det ailed assessment of t he presenc e, loc at ion, and ext ent of disease inv olv ing t he lung, mediast inum, pleura, sof t t issues, and bones of t he t horax. Abnormalit ies simult aneously af f ec t ing dif f erent c ompart ment s, suc h as bronc hogenic c arc inoma direc t ly inv ading t he c hest w all or diaphragm, c an be depic t ed. T he exc ellent spat ial resolut ion now obt ainable w it h mult iplanar ref ormat t ing f rom mult idet ec t or CT sc anning has f urt her improv ed t he CT depic t ion of anat omic regions more opt imally ev aluat ed by c oronal and sagit t al planes, suc h as t he superior sulc us and t he diaphragm.

PLEURA Anatomy T he pleura c omprises a single surf ac e lay er of mesot helial c ells and underly ing loose c onnec t iv e t issue, blood and ly mphat ic v essels, and nerv es. T he v isc eral pleura c ov ers t he lung, inc luding t he int erlobar f issures, and is c ont inuous w it h t he pariet al pleura lining t he mediast inum, c hest w all, and diaphragm.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1241

8 - Pleura, Chest Wall, and Diaphragm

Out side t he pariet al pleura, t here is a lay er of loose areolar c onnec t iv e t issue c ont aining ext rapleural f at of v ariable t hic kness, and out side t his t he t horac ic c av it y is lined by t he endot horac ic f asc ia. T hese lay ers of pleura, loose c onnec t iv e t issue, and endot horac ic f asc ia, in c ombinat ion w it h t he innermost int erc ost al musc le, are t y pic ally indist inguishable and appear as t hin line segment s along t he int erc ost al spac es, ext ending bet w een t he ribs, on t hinsec t ion CT (213). T he int erc ost al f at bet w een ribs separat es t his “ int erc ost al st ripe” f rom t he int ernal and ext ernal int erc ost al musc les. T he pleura and endot horac ic f asc ia are not normally v isible along t he int ernal rib margins on t hin- sec t ion CT , but in a minorit y of indiv iduals a t hin st ripe may be seen ov erly ing post erior ribs in t he low er t horax, likely represent ing t he subc ost al musc le (213). T he t ransv erse t horac ic musc le is usually v isible int ernal t o a rib end or c ost al c art ilage, and should not be mist aken f or pleural t hic kening. Only t he pariet al pleura is innerv at ed w it h sensory nerv es. A small amount of serous f luid (not det ec t able in most of t he pleural spac e by CT ) lubric at es t he pleural c av it y , t he pot ent ial spac e bet w een t he v isc eral and pariet al pleura and int erlobar f issures.

Interlobar Fissures T he f issures represent c lef t s in t he lung f ormed by t he int erf ac e of v isc eral pleura c ov ering t he lobes (140). F issures are t hus c omprised of t w o apposed pleural surf ac es. Sinc e t he pleural surf ac es represent t he periphery of t he lobes at t he end of t he pulmonary v asc ular t ree, t he loc at ion of t he f issures is seen on CT as zones of dec reased v asc ularit y along t he int erf ac e bet w een lobes; w it h t hinner sec t ions, P.570 t he f issures are seen as hy perat t enuat ing t hin lines if t he f issure is appropriat ely orient ed (see F ig. 5- 58) (27,140,155,304,390). T he major f issure separat es t he upper and low er lobes on t he lef t , and t he upper and middle lobes f rom t he low er lobe on t he right . T he upper port ion of t he major f issure is t y pic ally c onc av e ant eriorly , and t he inf erior port ion is c onc av e post eriorly . Ext rapleural f at may ext end int o t he low er end of t he f issure, and is a c ommon f inding on t he lef t on CT sc ans (see F ig. 5- 59) (130,145). T he minor f issure separat es t he middle and right upper lobes and is t y pic ally c onv ex upw ard. F issures may ac t as a barrier t o t he spread of inf ec t ion, t hereby c reat ing a sharply marginat ed border t o a pneumonia or neoplasm (161). How ev er, t he major f issures are inc omplet e in half of pat ient s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1242

8 - Pleura, Chest Wall, and Diaphragm or more, and t he minor f issure ev en more f requent ly and t heref ore may not ext end all t he w ay t o t he hilum (27,155,334,367). T his may allow air, inf ec t ion, and neoplast ic disease t o spread easily bet w een lobes. T here is no

c ommunic at ion bet w een t he right and lef t pleural c av it ies (194); t he right and lef t pleural surf ac es may c ome in c lose apposit ion at t he ant erior or post erior junc t ion lines, part ic ularly in st at es of hy perinf lat ion suc h as adv anc ed emphy sema.

Accessory Fissures Ac c essory f issures, f requent ly seen on CT examinat ions, represent inv aginat ions of t he v isc eral pleura, usually bet w een pulmonary segment s. Wit h high- resolut ion sc anning, it has been est imat ed t hat t hey are det ec t able in more t han 20% of pat ient s (20,27,161), and t hey are f requent ly inc omplet e. T he pulmonary segment s as w ell as t he bronc hial and art erial anat omy are normal in pat ient s w it h ac c essory f issures (161). T he inf erior ac c essory f issure, separat ing t he medial basal segment f rom t he rest of t he low er lobe, is t he most c ommon ac c essory f issure. It has been ident if ied in up t o 21% of c hest CT examinat ions using a 1.5- mm slic e t hic kness (20) (F ig. 8- 1). T he v ast majorit y of inf erior ac c essory f issures oc c ur on t he right and are inc omplet e. T he lef t minor f issure is t he next most c ommon ac c essory f issure, present in around 10% of pat ient s (20,26,168). It separat es t he lingula f rom t he remaining lef t upper lobe and may appear c ephalad or c audal t o t he minor f issure (26). T hough f ound in 5% t o 30% of aut opsy spec imens, t he superior ac c essory f issure has been f ound in less t han 5% of pat ient s by high- resolut ion CT (20,27,161). It is f ar more c ommon on t he right side (20,97,161). T his f issure arises below t he superior segment bronc hus and separat es t he apic al segment of t he low er lobe f rom t he basal segment s (463). It has an oblique orient at ion f rom it s superior aspec t at t he lat eral port ion of t he major f issure, c oursing inf eromedially t ow ard t he parav ert ebral region; port ions are c ommonly inc omplet e (97). T he azy gos f issure is t he result of t he f ailure of t he right post erior c ardinal v ein t o migrat e ov er t he apex of t he lung, result ing in t he ent rapment of a port ion of t he right upper lobe by t he azy gos v ein (306). T he result ing pleural sept um, w hic h is c omposed of f our lay ers of pleura (t w o v isc eral and t w o pariet al), is present in approximat ely 1% of indiv iduals (68). It has been demonst rat ed bot h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1243

8 - Pleura, Chest Wall, and Diaphragm P.571 radiographic ally (467) and by CT (20,27). T he int rapulmonary c ourse of t he azy gos v ein is t y pic ally sev eral c ent imet ers higher t han t he normal azy gos v ein (F ig. 8- 2; see F ig. 5- 61) (67,467). T he f issure is c onc av e medially and runs obliquely f rom t he apex dow n t o t he azy gos v ein. T he subt ended “ azy gos lobe” v aries in size and maint ains t he normal bronc hov asc ular

supply of t his region of t he right upper lobe. Muc h less c ommon is t he “ lef t azy gos lobe,” f ormed by t he lef t superior int erc ost al v ein (479).

F igure 8- 1 Inf erior ac c essory f issure. A, B: Cont iguous c ephaloc audal CT images show inf erior ac c essory f issure (ar r ow s) ext ending ant eriorly t o t he major f issure, and c audally t o t he diaphragmat ic pleura in (B).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1244

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 2 Azy gos f issure. A, B: Cephaloc audal CT images show f issure (ar r ow heads) w it h azy gos v ein arc h (ar r ow s) c oursing t hrough lung t o ent er t he superior v ena c av a more superiorly t han usual. C , D: In a dif f erent pat ient , c ephaloc audal CT images show t he azy gos f issure (ar r ow heads) separat ing a small port ion of t he medial right lung apex f rom t he rest of t he upper lobe, and ext ending inf eriorly t o t he azy gos v ein (ar r ow heads), w hic h ent ers t he superior v ena c av a more superiorly t han usual.

Ot her ac c essory f issures hav e been desc ribed, inc luding separat ions bet w een t he medial and lat eral segment s of t he right middle lobe (20), bet w een t he ant erior and lat eral basilar segment s of t he low er lobes (20), and bet w een t he segment s of t he lef t upper lobe and lingula (20,41).

Inferior Pulmonary Ligament

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1245

8 - Pleura, Chest Wall, and Diaphragm T he inf erior pulmonary ligament represent s union at t he hilum of t he pariet al pleura lining t he mediast inum and t he v isc eral pleura of t he lung (89). It c ourses inf eropost eriorly f rom t he inf erior pulmonary v ein, ly ing bet w een t he inf erior v ena c av a and azy gos v ein on t he right , and adjac ent t o t he esophagus on t he lef t (162,395,411) (F ig. 8- 3; see F ig. 5- 62). T he t erm inf er ior is ac t ually superf luous P.572 bec ause t here is no superior c ount erpart in humans (326,393). T he ligament w idens inf eriorly and may end just abov e or c ont inue ont o t he diaphragm, merging w it h t he diaphragmat ic pleura (395). It is seen as a t hin line or

sept um, ext ending lat erally int o t he lung f rom t he post erior mediast inal pleural margins, adjac ent t o or slight ly ant erior t o t he esophagus. In one st udy , using a 10- mm slic e t hic kness, t he inf erior pulmonary ligament w as v isible on t he lef t in 67% and on t he right in 37% of CT examinat ions (411). It may c ont ain blood v essels, ly mphat ic s, and ly mph nodes draining t he basal segment s of t he low er lobes. Paraesophageal v aric es and ly mphadenopat hy w it hin t he ligament c an simulat e parenc hy mal pat hology . T he inf erior pulmonary ligament div ides t he medial pleural spac es int o ant erior and post erior c ompart ment s, demonst rat ed w hen pleural ef f usions are present , and c auses t he low er lobe t o ret rac t medially w hen c ollapsed (F ig. 8- 4) (139).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1246

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 3 Inf erior pulmonary ligament . A– D: Cephaloc audal CT images show bilat eral inf erior pulmonary ligament s (ar r ow heads) slight ly ant erior t o t he esophagus and ext ending t o t he diaphragm. Not e in (B) t hat t he phrenic nerv e insert s on t he diaphragm (ar r ow s) ant erior t o t he inf erior v ena c av a. T hic kening of t he esophagus is due t o esophageal c anc er.

PLEURAL DISEASE Chest radiography serv es as t he primary t ec hnique f or det ec t ing most pleural abnormalit ies, suc h as ef f usions and pneumot horac es. How ev er, CT may be used t o c onf irm t he presenc e and ext ent of a pleural lesion, and also may be helpf ul in c harac t erizat ion. Import ant c lues, suc h as t he f at c ont ent of lipomas, c alc if ic at ions, ext rapleural f at t hic kening in asbest os- relat ed pleural disease, and t he w at er densit y of loc ulat ed ef f usions, may help t o dist inguish benign f rom pot ent ially malignant proc esses demonst rat ed on radiographs. Oc c asionally , pleural abnormalit ies, suc h as a plaque or small ef f usion, not v isible on c onv ent ional radiographs are det ec t ed w it h a CT examinat ion of t he t horax or upper abdomen perf ormed f or ot her indic at ions. In many c ases,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1247

8 - Pleura, Chest Wall, and Diaphragm how ev er, CT c annot prov ide a spec if ic hist ologic diagnosis f or a pleural proc ess or ev en det ermine w het her t he P.573

et iology is benign or malignant . T his is a def ic it shared by magnet ic resonanc e imaging (MRI).

F igure 8- 4 Pleural ef f usion sec ondary t o ly mphoma. CT demonst rat es sof t t issue at t enuat ion masses (ar r ow heads) along t he pleural surf ac e. Not e pleural ef f usion (Ef ) ext ending int o t he azy goesophageal rec ess adjac ent t o t he t horac ic aort a (Ao) and surrounding t he enhanc ing, at elec t at ic right low er lobe t et hered t o t he mediast inum by t he inf erior pulmonary ligament (ar r ow s). At , at elec t at ic lung; L, liv er.

T he CT f eat ures usef ul in loc alizing a lesion t o t he pleura are similar t o t hose employ ed w hen ev aluat ing c hest radiographs and inc lude: (a) a lent ic ular or c resc ent shape, (b) an obt use or t apering angle at t he c hest w all int erf ac e, and (c ) a w ell- def ined margin w it h t he adjac ent lung (F ig. 8- 5). Ext rapleural lesions may hav e a similar appearanc e, t hough an assoc iat ed ext rapleural sof t t issue mass, bone dest ruc t ion, or displac ed ext rapleural f at may help det ermine t he sit e of origin (178). Alt hough lesions f orming an ac ut e angle w it h t he c hest w all are t y pic ally parenc hy mal in origin, larger or pedunc ulat ed pleural lesions may inv aginat e int o t he pulmonary parenc hy ma, simulat ing an

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1248

8 - Pleura, Chest Wall, and Diaphragm int raparenc hy mal lesion. Ot her exc ept ions inc lude loc ulat ed pleural f luid c ollec t ions t hat bulge int o t he lung, c reat ing an ac ut e angle bet w een t he pleural lesion and t he c hest w all, or a parenc hy mal lesion suc h as bronc hogenic c arc inoma t hat may inf ilt rat e t he pleura, c reat ing an obt use rat her t han an ac ut e angle w it h t he c hest w all. T hus, alt hough CT may prov ide more prec ise delineat ion of t he ext ent of t he pat hologic proc ess t han c onv ent ional radiography , ov erlap in t he appearanc e of ext rapleural, pleural, and peripheral parenc hy mal lesions oc c urs. T he rout ine administ rat ion of int rav enous c ont rast media may not be nec essary w hen ev aluat ing t he pleura, but it c an help t o dif f erent iat e at elec t asis and c onsolidat ion, w hic h usually demonst rat e enhanc ement , f rom unenhanc ing pleural f luid (61). Enhanc ement of pleural nodules or masses c an aid t heir ident if ic at ion as a c ause of a pleural ef f usion. Int rav enous c ont rast also may be helpf ul in delineat ing areas of nec rosis and ident if y ing peripheral enhanc ement of empy emas. T he demonst rat ion of pulmonary v essels w it hin a lesion unequiv oc ally ident if ies t he loc at ion as parenc hy mal.

F igure 8- 5 Sc hemat ic draw ing of t he c ross- sec t ional appearanc e of ext rapleural (a), pleural (b), and peripheral pulmonary parenc hy mal (c )

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1249

8 - Pleura, Chest Wall, and Diaphragm

lesions. Ext rapleural lesions displac e t he ov erly ing pariet al and v isc eral pleura, result ing in an obt use angle bet w een t he lesion and t he c hest w all. An assoc iat ed c hest w all abnormalit y (e.g., rib erosion) may f urt her help def ine t he lesion as ext rapleural. Pleural lesions may remain c onf ined bet w een t he t w o pleural lay ers and c ause similar obt use angles w it h t he c hest w all, or t hey may bec ome pedunc ulat ed and prot rude int o t he pulmonary parenc hy ma, result ing in an ac ut e angle bet w een t he lesion and c hest w all. Subpleural parenc hy mal lesions generally result in an ac ut e angle w it h t he c hest w all, t hough inf ilt rat ion of t he pleura may c ause obt use angulat ion. T hus, t here may be c onsiderable ov erlap in t he appearanc es of t hese lesions. (Adapt ed f rom Naidic h DP, Zerhouni EA, Siegelman SS. Com put ed t om ogr aphy of t he t hor ax. New Y ork: Rav en Press, 1984.)

PLEURAL EFFUSION Pleural ef f usions are t he most c ommon pleural abnormalit y . Under normal c ondit ions, pleural f luid produc t ion and resorpt ion is an ongoing, dy namic proc ess, w it h f luid primarily produc ed by t he pariet al pleura and resorbed by t he pariet al pleura and probably t he v isc eral pleura (64,537). T he av erage v olume of f luid in t he normal pleural spac e has been measured at about 8 mL (range 4 t o 18 mL), or 0.13 mL/kg body w eight (358). T his f luid prov ides mec hanic al c oupling and lubric at ion bet w een t he lung and c hest w all (265,537). Pleural ef f usions dev elop w hen t he rat e of P.574 f luid produc t ion is inc reased, as in heart f ailure, or w hen resorpt ion is impaired, as in ly mphat ic obst ruc t ion by t umor. T he c ause may be sy st emic (e.g., hy poalbuminemia), loc alized (e.g., inf lammat ory , neoplast ic ), or abdominal (e.g., panc reat it is) in et iology (49,193). Pat ient s w it h massiv e asc it es may dev elop pleural ef f usions as a result of t ransdiaphragmat ic f low of asc it es t hrough ly mphat ic c hannels or diaphragm def ec t s (434). CT may demonst rat e t hat a mass seen on plain radiographs is pleural f luid (378). T he exc ellent sof t t issue c ont rast prov ided by CT c an be of v alue in sort ing out pleural f rom parenc hy mal disease w hen a hemit horax is opac if ied on c hest radiography , espec ially if int rav enous c ont rast is administ ered.

Fluid Types and Causes

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1250

8 - Pleura, Chest Wall, and Diaphragm Clinic ally , pleural ef f usions are c lassif ied as t ransudat es or exudat es, ac c ording t o t heir bioc hemic al c omposit ion. An ef f usion is c lassif ied as an exudat e if it has a pleural f luid t o serum prot ein rat io great er t han 0.5, an absolut e lac t at e dehy drogenase (LDH) v alue great er t han 200 IU, or a pleural f luid t o serum LDH rat io great er t han 0.6 (260,410). Exudat es may be f urt her c harac t erized by gluc ose lev el (less t han serum in empy ema, rheumat oid

disease, t uberc ulous pleurisy , and malignanc y ), pH (less t han 7.2 in empy ema, esophageal rupt ure, hemot horax, rheumat oid disease, and sy st emic ac idosis), amy lase (high in panc reat it is and esophageal rupt ure), and t rigly c erides (great er t han 100 mg/dL in c hy lot horax). A high w hit e c ell c ount (great er t han 10,000 per c ubic mm) and posit iv e Gram st ain or c ult ure may oc c ur w it h inf ec t ious pleurit is. A high red c ell c ount (great er t han 100,000/mm3) c an oc c ur in t rauma, pulmonary embolism, and malignanc y (410). T he dist inc t ion bet w een t ransudat iv e and exudat iv e ef f usions is import ant in dif f erent ial diagnosis. T ransudat es are t he result of an inc rease in c apillary hy drost at ic pressure or a dec rease in c olloid osmot ic pressure, result f rom sy st emic rat her t han pleural pat hology , and are t y pic ally bilat eral (227,537). Congest iv e heart f ailure is by f ar t he most c ommon c ause, f ollow ed by hy poprot einemic st at es suc h as c irrhosis or nephrot ic sy ndrome (291,410). Exudat es are t he result of loc al pat hologic proc esses inv olv ing t he v isc eral or pariet al pleural surf ac e t hat result in inc reased c apillary permeabilit y (227,537). T hey may be t he result of a w ide v ariet y of c auses inc luding inf ec t ion, t umor, pulmonary embolism, drugs, radiat ion t herapy , c onnec t iv e t issue diseases (espec ially sy st emic lupus ery t hemat osis and rheumat oid art hrit is), post my oc ardial inf arc t ion (Dressler's sy ndrome), post peric ardiot omy , and abdominal diseases (291,410). T he pat hophy siology of exudat iv e ef f usions may inv olv e disrupt ion of t he pleural surf ac e or ly mphat ic obst ruc t ion; t heref ore, ef f usions c aused by malignanc y (e.g., lung c anc er, ly mphoma) may be eit her malignant (a result of neoplast ic spread t o t he pleura) or benign (307). Alt hough CT is of limit ed v alue in dist inguishing t ransudat es f rom exudat es (339), t hic kening of t he pariet al pleura almost alw ay s indic at es t hat an ef f usion is an exudat e (19). Pleural t hic kening, how ev er, is not alw ay s seen w it h a malignanc y or parapneumonic ef f usion (19). Wit h t ransudat es, pleural t hic kening and/or enhanc ement is not t y pic ally seen on CT . If t he et iology of a pleural ef f usion is not ev ident t hrough c linic al inf ormat ion and t horac ent esis, CT may rev eal ot her f indings t hat indic at e t he c ause. Conf ident noninv asiv e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1251

8 - Pleura, Chest Wall, and Diaphragm dist inc t ion bet w een t ransudat iv e and exudat iv e pleural ef f usions on t he basis of MRI signal c harac t erist ic s present ly c annot be ac c omplished (96). T he MRI

assessment is c omplic at ed by t he mov ement of pleural f luid during respirat ion, w hic h c an c reat e f low art if ac t s and v ariably alt er t he signal int ensit y t o produc e a het erogeneous appearanc e (510).

Computed Tomography Findings Attenuation of Fluid Most pleural ef f usions, w het her t ransudat iv e or exudat iv e, are of homogeneous, near- w at er at t enuat ion. Higher densit y ef f usions are almost alw ay s exudat es (19). Pleural ef f usions, ev en w hen small, usually result in passiv e at elec t asis of t he adjac ent lung (F igs. 8- 6, 8- 7, and 7- 75). T his may be dist inguished f rom lung c onsolidat ion or t he t hin st ripe of t he diaphragm by t he c harac t erist ic enhanc ement of t he at elec t at ic lung, or by t he bandlike shape and sharper margins of t he at elec t at ic lung on unenhanc ed sc ans. When t hese f eat ures are not present , dist inc t ion may not be possible. Pleural f luid hav ing at t enuat ion similar t o or higher t han sof t t issue is suggest iv e of a hemot horax (F ig. 8- 8). Hemot horac es may be inhomogeneous in at t enuat ion and c ont ain f luid lev els of dif f erent at t enuat ion. T he inc reased at t enuat ion is a result of t he high prot ein c ont ent , w hic h also c an be seen w it h ot her c omplex f luid c ollec t ions hav ing a high prot ein c ont ent or bec oming organized. F ormat ion of f ibrin c lot s may be seen on CT as nodular pleural pseudot umors w it hin t he pleural f luid (260). A hemot horax c an lead t o signif ic ant pleural f ibrosis (f ibrot horax) and c alc if ic at ion. Causes of hemot horax inc lude t rauma, malignanc y , hy perc oagulable st at es, pulmonary inf arc t ion, rupt ured aort ic dissec t ion, aneury sm, art eriov enous malf ormat ion, and pleural endomet riosis (212). On MRI, subac ut e or c hronic hemorrhage show s high signal w it h T 1 and T 2 w eight ing (249). Chy lot horax ref ers t o an ef f usion c ont aining ly mphat ic f luid, w hic h has a high t rigly c eride c ont ent (124) and c an result in a CT at t enuat ion less t han t hat of w at er (F ig. 8- 9) (272). More t y pic ally , t he at t enuat ion is c lose t o w at er, as a result of t he high prot ein c ont ent (181). On MRI, c hy lot horac es t y pic ally appear as simple f luid, but may hav e signal c harac t erist ic s of f at (249). Chy lous ef f usions may result f rom damage t o t he t horac ic duc t or ot her large ly mphat ic s, slow leak f rom pleural ly mphat ic s, v enous obst ruc t ion, or c ommunic at ion of t he pleural spac e w it h c hy lous asc it es (181). About half of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1252

8 - Pleura, Chest Wall, and Diaphragm c hy lot horac es are relat ed t o t umors, most ly ly mphoma. Surgery is t he most c ommon t raumat ic c ause f or c hy lot horax. T he t horac ic duc t runs c ephalad f rom P.575 t he diaphragm t o t he right of t he midline bet w een t he aort a and azy gos v ein, unt il c rossing t o t he lef t at about t he t hird or f ourt h t horac ic v ert ebra t o empt y int o t he lef t subc lav ian v ein; t he predominant ly right - sided c ourse

explains w hy t raumat ic c hy lot horax usually oc c urs on t he right (202). Inv asion by neoplasm is anot her c ause of t horac ic duc t obst ruc t ion, w it h ly mphoma t he most c ommon nont raumat ic et iology (202). Leakage f rom pleural ly mphat ic s may be t he c ause of c hy lot horax in ly mphangioleiomeiomy omat osis, and in t horac ic duc t obst ruc t ion (181). Impairment of t horac ic duc t and right ly mphat ic t runk drainage result ing f rom obst ruc t ion of t he superior v ena c av a or bot h brac hioc ephalic t runks is anot her pot ent ial mec hanism (181).

F igure 8- 6 A, B: Pulmonary at elec t asis. Cont rast - enhanc ed CT examinat ion of t he t horax show ing t he c harac t erist ic enhanc ement of at elec t at ic lung (ar r ow heads) in t his pat ient w it h small bilat eral pleural ef f usions.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1253

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 7 Large pleural ef f usion (E) w it h adjac ent at elec t asis. Not e t he c harac t erist ic enhanc ement of t he at elec t at ic lung. T he t hin line of enhanc ement at t he int erf ac e of t he c hest w all and f luid (ar r ow heads) represent s t he pariet al pleura separat ed f rom t he t horac ic inv est ing f asc ia and innermost int erc ost al musc le by abundant ext rapleural f at . T he linear enhanc ing st ruc t ure in t he lef t paraspinal region (ar r ow ) is a normal int erc ost al v essel.

Pseudoc hy lous pleural ef f usion (181,202,242), w hic h c ont ains lipid but is nonc hy lous, may be seen in c hronic pleural ef f usions. T uberc ulous empy ema and rheumat oid disease are t he most c ommon et iologies. Impaired resorpt ion of c holest erol f rom degenerat ed red and w hit e blood c ells result ing f rom c hronic pleural t hic kening is t he suggest ed mec hanism. When milky pleural f luid is assoc iat ed w it h pleural t hic kening on CT , pseudoc hy lot horax should be suspec t ed, sinc e c hy lot horax is usually not assoc iat ed w it h pleural t hic kening. A f at - f luid lev el or f at - milk of c alc ium lev el may be seen on CT (211,242,465). Urinot horax is of w at er at t enuat ion and may result f rom dissec t ion of a ret roperit oneal urinoma in pat ient s w it h a urinary t rac t obst ruc t ion (429); it is t y pic ally unilat eral. T horac ent esis remains a requirement f or det ermining t he c omposit ion of most pleural ef f usions, and w het her t he pleural spac e is inf ec t ed or c ont ains blood or malignant c ells.

Location and Volume of Fluid

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1254

8 - Pleura, Chest Wall, and Diaphragm CT is w ell suit ed t o ev aluat ing t he loc at ion and size of f luid c ollec t ions, and

may demonst rat e a pleural ef f usion not det ec t ed on radiographs. In t he supine posit ion of most CT examinat ions, mobile pleural f luid init ially c ollec t s in t he post eromedial hemit horax, w hic h is t he most dependent port ion of t he pleural spac e. T he size of t he c ollec t ion dec reases progressiv ely in t he c audal direc t ion on sc ans t hrough t he lung bases int o t he upper abdomen (169). As an ef f usion inc reases in size, it c onf orms t o t he pleural spac e and may ext end lat erally , displac ing lung aw ay f rom t he t horac ic w all. T he lat eral aspec t of t he major f issure may bec ome f illed w it h f luid point ing t ow ard t he hilum. Pleural ef f usions usually are assoc iat ed w it h at least some passiv e at elec t asis of t he ov erly ing lung. Large pleural ef f usions usually result in low er lobe c ollapse w it h ant erior displac ement of t he c ollapsed lobe in t he supine posit ion, as opposed t o t he post eromedial P.576 loc at ion of t y pic al low er lobe c ollapse c aused by endobronc hial obst ruc t ion (370).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1255

8 - Pleura, Chest Wall, and Diaphragm F igure 8- 8 Hemot horac es: as a c omplic at ion of c ent ral v enous c at het er plac ement in a pat ient on w arf arin (Coumadin) w it h a markedly elev at ed prot hrombin t ime (A), produc ing c ompressiv e at elec t asis of t he lef t lung

(ar r ow s) (B) and on t he right side f ollow ing perc ut aneous renal biopsy (C , D). F luid c ollec t ions are of a mixed, part ly high at t enuat ion. Not e ret roperit oneal hemorrhage displac ing right kidney ant eriorly in (D). H, hemat oma.

If nec essary , sc ans c an be obt ained w it h t he pat ient prone or in a lat eral dec ubit us posit ion t o ev aluat e t he mobilit y of f luid or t o dif f erent iat e a small dependent ef f usion f rom pleural t hic kening. CT also c an ident if y loc ulat ed pleural f luid in nondependent loc at ions and dist inguish pleural f luid c ollec t ions f rom pleural masses or lung parenc hy mal lesions. Loc ulat ed c ollec t ions are t y pic ally lent ic ular in c ross sec t ion. F luid loc ulat ed w it hin a f issure bec ause of adhesions may produc e a “ pseudot umor,” w hic h c an simulat e an int rapulmonary mass. T he sharp pleural margins and w at er densit y of t he c ollec t ion should be c lues t o t he c orrec t et iology . T he v olumet ric nat ure of helic al CT allow s quant it at iv e det erminat ion of t he amount of pleural f luid present , if desired. T his c an be easily done by t rac ing t he margins of a pleural ef f usion t o det ermine t he c ross- sec t ional area, mult iply ing by t he slic e t hic kness, and summing t he result ing measurement s obt ained f rom eac h slic e. A simpler and f ast er met hod of mult iply ing t he c ephaloc audal lengt h of t he ef f usion by t he square of t he great est dept h in t he t ransv erse plane y ields reasonable est imat es, t hough great er error is seen w it h loc ulat ed or subpulmonic c ollec t ions (316). Pleural ef f usions are bilat eral in t he majorit y of c ases of c ongest iv e heart f ailure and are more of t en right - sided w hen unilat eral. T he lesser amount of f luid of t en seen on t he lef t probably is a result of c ardiac mot ion, w hic h st imulat es ly mphat ic resorpt ion. Isolat ed lef t - sided pleural ef f usions c an be seen f ollow ing rupt ure of t he esophagus, dissec t ing aneury sms, and t raumat ic rupt ure of t he aort a. Panc reat it is t y pic ally leads t o lef t - sided ef f usions but may P.577 c ause isolat ed right - sided ef f usions and oc c asionally pleural pseudoc y st s (35).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1256

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 9 Chy lot horax. A small, nondependent c omponent of t his ef f usion in t he lef t post pneumonec t omy spac e has at t enuat ion low er t han w at er, c harac t erist ic of c hy lous f luid.

Distinguishing Between Pleural Fluid and Ascites Alt hough at t imes it may appear dif f ic ult t o c learly dist inguish bet w een a pleural ef f usion and asc it es on CT , c aref ul ev aluat ion of serial sec t ions should allow a c onf ident dist inc t ion bet w een t he t w o and ident if ic at ion of bot h if present (11,169,177,339,348). Mult iplanar rec onst ruc t ions f rom v olumet ric sc ans also may be helpf ul. T he displac ed c r us sign ref ers t o t he loc at ion of pleural f luid post erior t o t he diaphragmat ic c rus, w idening t he angle and displac ing t he diaphragm aw ay f rom t he spine (F igs. 8- 10 and 8- 11). Asc it es w ill be f ound ant erolat eral t o t he c rus and w ill hav e t he opposit e ef f ec t , displac ing t he diaphragm t ow ard t he spine (112) and inc reasing in v olume in t he c audal direc t ion int o t he abdomen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1257

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 10 Sc hemat ic draw ing illust rat ing relat ionship of pleural ef f usion and asc it es t o t he diaphragmat ic c rus. T he t hic k blac k line represent s t he right hemidiaphragm and it s medially ext ending c rus. A pleural ef f usion lies post erior (ext ernal) t o t he diaphragm and ext ends medially adjac ent t o t he spine. Large amount s of pleural f luid may displac e t he c rus ant eriorly and lat erally . Asc it es lies ant erior (int ernal) t o t he diaphragm, prev ent ed f rom ext ending medially by t he c oronary ligament on t he right side. (Modif ied f rom Halv orsen RA, F edy shin PJ, Korobkin M, et al. CT dif f erent iat ion of pleural ef f usion f rom asc it es. An ev aluat ion of f our signs using blinded analy sis of 52 c ases. Inv est Radiol 1986; 21:391–395.)

T he diaphr agm sign ref ers t o depic t ion of t he diaphragm w hen bot h asc it es and pleural f luid are present . In t hese P.578 c ases, f luid seen int ernal t o t he diaphragm is subdiaphragmat ic and f luid out side t he diaphragm is in t he pleural spac e (F ig. 8- 12) (177). An exc ept ion oc c urs w it h v ery large pleural ef f usions, w hic h may inv ert t he hemidiaphragm (198). In t his c ase, asc it es is seen out side t he c onc ent ric rings of t he diaphragm and pleural f luid appears int ernal t o t he diaphragm (11). A part ially c ollapsed low er lobe c an appear as a t hin linear opac it y w it hin a pleural f luid c ollec t ion (see F ig. 8- 6) and should not be c onf used w it h pleural f luid abov e and asc it es below t he diaphragm (458). T his at elec t at ic lung c an be dist inguished f rom t he diaphragm bec ause it is usually t hic ker, enhanc es w it h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1258

8 - Pleura, Chest Wall, and Diaphragm c ont rast , and c an be f ollow ed on c ont iguous c ephalad sc ans int o t he more normal lung (126,176,177).

F igure 8- 11 Large pleural ef f usion. Cephaloc audal CT images. A: Right pleural ef f usion (E) t hat t rac ks post erior t o t he c rus of t he right hemidiaphragm and medially int o t he azy goesophageal rec ess. B: T he f luid v olume is smaller on t his more c audal image. A small amount of f at is int erposed bet w een t he bare area of t he liv er (shor t ar r ow s) and t he ant erior surf ac e of t he right c rus (long ar r ow s).

F igure 8- 12 Sc hemat ic draw ing illust rat ing relat ionship of pleural ef f usion and asc it es t o t he diaphragm. T he solid blac k line represent s t he diaphragm. T he posit ion of t he f luid relat iv e t o t he diaphragm ident if ies w here t he f luid lies. F luid inside t he diaphragm is asc it es; f luid out side (peripheral) t he diaphragm is pleural. S, spleen. (Modif ied f rom Halv orsen RA, F edy shin PJ, Korobkin M, et

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1259

8 - Pleura, Chest Wall, and Diaphragm al. CT dif f erent iat ion of pleural ef f usion f rom asc it es. An ev aluat ion of f our signs using blinded analy sis of 52 c ases. Inv est Radiol 1986;21: 391–395.)

T he ext ent of asc it es is limit ed by t he perit oneal ref lec t ions. T he bar e ar ea of t he liv er c reat ed by t he right c oronary ligament rest ric t s perit oneal f luid f rom mov ing post eromedially on t he right (F ig. 8- 13). A c orresponding but smaller area of t he spleen demarc at ed by t he splenorenal ligament prev ent s t he post eromedial ext ension of perit oneal f luid on t he lef t side (503). F luid seen in t hese areas is almost inv ariably pleural. Massiv e asc it es may , how ev er, ext end beneat h t he domes of t he hemidiaphragms and medially abov e t he bare areas on bot h sides. T he int er f ac e sign has been desc ribed in ref erenc e t o t he sharp margin bet w een asc it es and t he liv er or spleen and t he hazy int erf ac e seen bet w een a pleural ef f usion and t he diaphragm and liv er or spleen t oget her (488). T his is a relat iv ely unimport ant dist inguishing f eat ure, w hic h may not ev en be relev ant w it h v olumet ric sc anning and slic e t hic knesses of 5 mm or less; t he ot her dist inguishing f eat ures should be suf f ic ient t o demonst rat e w het her t he f luid is pleural or asc it ic (F ig. 8- 14).

F igure 8- 13 Sc hemat ic draw ing of sagit t al sec t ion t hrough t he right upper quadrant of t he abdomen; lef t side of t he diagram is post erior (dorsal). Asc it es (w hit e ar ea) c annot ext end behind t he liv er (L) int o t he nonperit onealized bare area (solid blac k) demarc at ed by t he superior and inf erior c oronary ligament s, w hereas pleural f luid (c oar se-lined ar ea) c an go behind t he liv er in t he deep post erior sulc us. When asc it es is massiv e, a small

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1260

8 - Pleura, Chest Wall, and Diaphragm amount of f luid may ext end post erior t o t he liv er along it s most c ephalad and

c audad margins out side t he bare area. RK, right kidney ; T C, t ransv erse c olon. (Modif ied f rom Halv orsen RA, F edy shin PJ, Korobkin M, et al. CT dif f erent iat ion of pleural ef f usion f rom asc it es. An ev aluat ion of f our signs using blinded analy sis of 52 c ases. Inv est Radiol 1986;21:391–395.)

EMPYEMA An empy ema is a grossly purulent exudat iv e pleural ef f usion (w hit e blood c ell c ount great er t han 5,000/mm3), w hic h may be c ult ure or Gram st ain posit iv e (260,339). Empy emas most c ommonly oc c ur as t he result of an inf ec t ed parapneumonic ef f usion f ollow ing py ogenic bac t erial pneumonia, but c an be seen w it h t uberc ulosis (208), f ungal inf ec t ions, or as a c omplic at ion of a lung absc ess, sept ic pulmonary inf arc t ion, or t rauma (339). Inf ec t ion also may spread t o t he pleura f rom ost eomy elit is of t he spine or a subdiaphragmat ic absc ess. An iat rogenic pleural inf ec t ion may f ollow t horac ic surgery , t horac ent esis, or perc ut aneous needle aspirat ion. T he inc idenc e of parapneumonic pleural ef f usions is dependent t o some degree on t he inf ec t ing organism, ranging f rom about 10% f or pneumonias c aused by Pneum oc oc c us t o ov er half f or t hose c aused by St aphy loc oc c us py ogenes. Most parapneumonic ef f usions, w hic h are c omposed of uninf ec t ed f luid result ing f rom inf lammat ion of t he v isc eral pleura and inc reased c apillary permeabilit y , resolv e w it h appropriat e ant ibiot ic t reat ment . How ev er, some do bec ome inf ec t ed and progress t o a t rue empy ema, in w hic h large numbers of poly morphonuc lear leukoc y t es ac c umulat e in t he pleural spac e w it h f ibrin deposit ed ov er t he v isc eral and pariet al pleura. T hic kening of t he pleura may dev elop w it hin sev eral day s, and as a c onsequenc e t here is impairment of f luid resorpt ion and a t endenc y t ow ard loc ulat ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1261

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 14 Asc it es and pleural ef f usion. A: In pat ient w it h nephrot ic sy ndrome, some at elec t at ic lung (ar r ow heads) is seen c audally in t he right hemit horax, w it h an assoc iat ed pleural ef f usion (E) and asc it es (A) seen ant erolat eral t o t he dome of t he right hemidiaphragm. A small lef t pleural ef f usion also is present . B: More c audal images show a sharp int erf ac e of asc it es (A) w it h t he liv er (L) ant eriorly , w it h less dist inc t int erf ac e of t he pleural ef f usion (E) and right hemidiaphragm and liv er post eriorly .

P.579 CT c an depic t t he pleural f luid and t hic kening of t he adjac ent v isc eral and pariet al pleura, and f requent ly edemat ous inf lammat ion of t he ext rapleural t issues as w ell. T he pleural surf ac es bec ome organized w it h f ibrosis and v asc ular ingrow t h result ing in an inc reased at t enuat ion and marked c ont rast enhanc ement around t he margins of t he pleural f luid, t ermed t he “ split pleura” sign (F igs. 8- 15 and 8- 16). T his c irc umf erent ial enhanc ement , seen in ov er t w o t hirds of empy emas, is a usef ul sign in ident if y ing inf ec t ed pleural f luid c ollec t ions (470). Pleural neoplasm and inf lammat ory disease also may produc e t his sign (19,313,339,507). Lac k of pleural t hic kening or enhanc ement does not exc lude inf ec t ion of a pleural f luid c ollec t ion. Generally , plain c hest radiography , somet imes in c onjunc t ion w it h dec ubit us posit ioning, suf f ic es t o diagnose a pleural f luid c ollec t ion and dist inguish it f rom a peripheral pulmonary parenc hy mal proc ess. Ult rasound c an also be ext remely helpf ul in c orroborat ing pleural f luid and in guiding aspirat ion, alt hough it is of lesser v alue in c onf irming parenc hy mal disease (313). At t imes, how ev er, dist inc t ion bet w een a loc ulat ed pleural c ollec t ion and a parenc hy mal proc ess may not be possible w it h P.580

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1262

8 - Pleura, Chest Wall, and Diaphragm c onv ent ional radiologic t ec hniques. T his also c an be t rue w hen a

bronc hopleural or esophagopleural f ist ula is present (474,515), produc ing air in t he pleural spac e (F igs. 8- 16, 8- 17, 8- 18); t his oc c urs in approximat ely 50% of empy emas w hen peripheral lung nec rosis c reat es a c ommunic at ion bet w een an airw ay (usually a bronc hiole) and t he pleural spac e. Air w it hin an empy ema also may result f rom t horac ent esis, or rarely , f rom gas- produc ing organisms. CT c an be v aluable in dif f erent iat ing suc h a py opneumot horax f rom a nec rot izing parenc hy mal proc ess, bot h of w hic h may appear on plain radiographs as a “ c av it ary ” lesion c ont aining an air–f luid lev el adjac ent t o t he c hest w all. Ac c urat e diagnosis is c rit ic al bec ause of t he disparat e t reat ment s f or t hese serious suppurat iv e lesions. Proper t herapy of an empy ema requires t horac ost omy t ube drainage, w hereas a lung absc ess is appropriat ely managed using ant ibiot ic s and post ural drainage, w it h perc ut aneous or bronc hosc opic drainage or surgic al resec t ion reserv ed f or w hen ant ibiot ic t reat ment f ails (12,32,197,509). Alt hough a role f or CT in det ermining t he need f or dec ort ic at ion in empy ema has not been demonst rat ed, it c an be used t o ev aluat e pleural rind t hic kness, t he presenc e of loc ulat ions, t he ef f ec t iv eness of c hest t ube drainage, and t he presenc e of unexpanded, “ t rapped” lung af t er drainage (260).

F igure 8- 15 Empy ema. A: T hic kened enhanc ing pariet al pleura (ar r ow heads) is seen. Not e t he edema and inf lammat ion of t he ext rapleural sof t t issues in t he post erior lef t hemit horax (ar r ow s). B: Lung w indow set t ing show s t he v essels and bronc hi c ompressed and displac ed by t he ext rapulmonary c ollec t ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1263

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 16 Empy ema, split pleura sign. A: Dif f use t hic kening and enhanc ement of bot h v isc eral and pariet al pleura surround t he f luid c ollec t ion in t he right pleural spac e. Small f oc i of gas t hat do not rise t o t he t op of t he f luid indic at e t he c omplex nat ure of t he c ollec t ion, w hic h is likely v isc ous or sept at ed. Not e adjac ent c ollapsed and c onsolidat ed lung. B: In anot her pat ient , a small lef t empy ema also demonst rat es c harac t erist ic t hic kening and enhanc ement of v isc eral and pariet al pleura.

F igure 8- 17 Empy ema. Right empy ema (Em) c ont aining gas, presumably due t o a bronc hopleural f ist ula. Dependent f luid c ollec t ion w it hout pleural enhanc ement is seen at t he lef t c onsist ent w it h a simple ef f usion (Ef ). A: T he pleura is t hic kened and enhanc es (ar r ow heads). Again, not e t he edema of t he sof t t issue ext ernal t o t he pariet al pleura (open ar r ow s). B: A more c ephalad image show s a more rounded appearanc e t o t he empy ema, w hic h simulat es a lung absc ess at t his lev el.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1264

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 18 Esophagopleural f ist ula. Direc t c ommunic at ion bet w een t he esophagus (ar r ow ) and a right empy ema (E) as a result of a perf orat ion f ollow ing endosc opic biopsy of an esophageal c arc inoma.

P.581

Empyema Versus Lung Abscess Ident if ic at ion of a c ent ral lung absc ess t y pic ally is not dif f ic ult , alt hough an absc ess may be dif f ic ult t o dif f erent iat e f rom a c av it ary neoplasm. T he problem oc c urs w it h peripheral lesions, w here dist inc t ion bet w een an empy ema and absc ess may not be possible w it h c onv ent ional radiographs, and c linic al hist ories are of t en insuf f ic ient t o allow disc riminat ion (28). F ort unat ely , CT c an reliably dist inguish bet w een an absc ess and empy ema in most c ases. Sev eral morphologic f eat ures are helpf ul f or dif f erent iat ion bet w een a pleural and parenc hy mal proc ess; bec ause none is inf allible, t hey are best used in c ombinat ion (28,470,523). F eat ures t hat are helpf ul in making t he dist inc t ion inc lude t he shape of t he f luid c ollec t ion and c harac t erist ic s of t he w all, adjac ent pleura, and lung (F ig. 8- 19) (12,260). T he c ross- sec t ional f ormat of CT images bet t er delineat es t he t hree- dimensional (3D) shape of t he lesion and it s pleuroparenc hy mal int erf ac e, generally permit t ing ac c urat e loc alizat ion and dist inc t ion of t he predominant proc ess (F igs. 8- 20 and 8- 21). An empy ema generally has a lent ic ular shape w it h obt use margins t hat t aper and c onf orm t o t he pleural spac e. In c ont rast , a peripheral lung absc ess

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1265

8 - Pleura, Chest Wall, and Diaphragm usually has a spheric al or oblong shape t hat f orms an ac ut e angle w it h t he c hest w all, alt hough c onc omit ant pleural disease may c ause t he angle t o bec ome obt use. While generally not nec essary , sc anning t he pat ient in a lat eral dec ubit us or prone posit ion may demonst rat e f luid mobilit y and c hange in t he shape of an empy ema. A lung absc ess t ends t o remain rigidly spheric al w it h an equidimensional air–f luid lev el. Mult iplanar ref ormat t ing c an be usef ul in depic t ing t he 3D shape.

Wit h empy emas, t he inner surf ac e of t he t hic kened and enhanc ing v isc eral and pariet al pleura is t y pic ally smoot h (see F igs. 8- 15 and 8- 16) (28). In c omparison, a lung absc ess, w hic h represent s a loc alized area of lung nec rosis, usually has t hic k, irregular w alls, espec ially int ernally (F ig. 8- 22) (470). Mult iple small side poc ket s may be present .

F igure 8- 19 Sc hemat ic draw ing demonst rat ing c ross- sec t ional f eat ures of an empy ema (E) and a lung absc ess (A). T he empy ema is lent ic ular in shape w it h t hin w alls and a smoot h inner surf ac e, f orming an obt use margin w it h t he c hest w all; t he pulmonary v essels are c ompressed and displac ed around t he empy ema. In c ont rast , t he lung absc ess is spheric al w it h t hic k irregular w alls and f orms an ac ut e angle w it h t he c hest w all; pulmonary v essels ext end direc t ly t ow ard t he lesion. (Modif ied f rom Winer- Muram HT , Kauf f man WM, Gronemey er SA, et al. Primit iv e neuroec t odermal t umors of t he c hest w all [Askin t umors]: CT and MR f indings. AJR Am J Roent genol 1993;161:265–268.)

An empy ema usually f orms a sharp border w it h t he adjac ent lung, w hic h is f requent ly c ompressed, result ing in t he gradual displac ement and bow ing of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1266

8 - Pleura, Chest Wall, and Diaphragm

peripheral pulmonary v essels and bronc hi around it s c irc umf erenc e (F igs. 8- 15, 8- 20, and 8- 23). T he c ompressed lung may enhanc e similarly t o t he t hic kened pleura, so t hat t hic kening and enhanc ement of t he pariet al pleura is not separat ely dist inguishable. T he ext rapleural f at may be edemat ous in pat ient s w it h an empy ema, result ing in elev at ion of t he pariet al pleura aw ay f rom t he c hest w all (F ig. 8- 24). Lung dest ruc t ion result s in abrupt t erminat ion of bronc hi and v essels at t he margin of a lung absc ess, and t he parenc hy ma surrounding t he absc ess is of t en inf ec t ed (470). T he presenc e of c onsolidat ed lung, air w it hin t he c ollec t ion, f ree pleural f luid, and sept at ed or mult iple c ollec t ions (see F ig. 8- 24) may be assoc iat ed w it h eit her an absc ess or an empy ema and are nonc ont ribut ory f indings in dist inguishing bet w een t hem (470). In some c ases an empy ema and lung absc ess c oexist (F ig. 8- 25), t y pic ally w it h bot h being t he result of a nec rot izing pneumonia. Sinc e absc esses are generally indist inguishable f rom ot her c av it ary lung masses, suc h as c av it ary lung c anc er and lesions of Wegener granulomat osis, c orrelat ion w it h t he c linic al present at ion and imaging f ollow - up t o ev aluat e f or resolut ion are import ant .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1267

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 20 Empy ema. A, B: Post eroant erior and lat eral c hest radiographs in a 32- y ear- old w oman w it h f ev er and a c linic al diagnosis of pneumonia rev eal an air–f luid lev el on t he right w it h c onf lic t ing loc alizing f indings: t he loc ulat ed pleural f luid lat erally and ext ension of t he air–f luid lev el t o t he pleural margin suggest empy ema, but t he similar lengt h of t he air–f luid lev el on bot h v iew s suggest s lung absc ess. C : Cont rast - enhanc ed CT rev eals t hat t he air–f luid lev el has mov ed t o t he lat eral aspec t of t he pleural spac e w it h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1268

8 - Pleura, Chest Wall, and Diaphragm t he pat ient supine, and t he pariet al pleura is enhanc ing and t hic kened, c harac t erist ic of an empy ema. No lung absc ess w as ident if ied. Not e enhanc ement of c ompressed, at elec t at ic lung bet w een loc ulat ed c omponent s of t he empy ema.

P.582

Fluid in Preexisting Airspaces F luid may ac c umulat e in a subpleural bulla as a result of an inf lammat ory response of t he w all t o adjac ent pneumonit is, analogous t o a parapneumonic pleural ef f usion (536). In most c irc umst anc es, t he bullae are not t ruly inf ec t ed. Obst ruc t ion of adjac ent bronc hioles result ing f rom inf lammat ion and muc us plugging may play a role in prev ent ing or impairing adequat e drainage. CT f indings in suc h pat ient s may simulat e a loc ulat ed pleural ef f usion, hy dropneumot horax, or empy ema. Def init iv e radiologic diagnosis may require c omparison w it h old c hest radiographs or a prior CT examinat ion t o doc ument t he presenc e of preexist ing bullous lung disease (F ig. 8- 26). Suggest iv e but less def init iv e w ould be demonst rat ion of c ont ralat eral or adjac ent bullae. A pleural proc ess might be more likely if t he loc ulat ed spac e has an ellipt ic al shape or obt use margin w it h t he c hest w all, or if c oexist ent pleural c ollec t ions are seen at ot her sit es. In some c ases, dist inc t ion bet w een f luid w it hin a bulla or t he pleural spac e may not be possible.

Placement of Chest Tubes and Other Support Devices An addit ional import ant applic at ion of CT is t o prec isely loc alize empy ema poc ket s t o assist in proper t horac ost omy t ube plac ement and drainage (461,469). Clearer depic t ion of t he exac t sit e and ext ent of t he empy ema is possible, and radiographic ally oc c ult loc ulat ions may be ident if ied. In pat ient s not responding w ell c linic ally t o t he usual t horac ost omy t ube drainage, CT c an demonst rat e loc ulat ions as w ell as t he posit ion of t he t ube relat iv e t o t he ext ent of any residual pleural c ollec t ion (186). Similarly , any undrained hemot horax f ollow ing t rauma, w hic h might serv e as a nidus f or a subsequent empy ema or rest ric t f ull lung reexpansion, c an be ident if ied (490). An improperly drained empy ema is muc h more c ommonly a c onsequenc e of t ube malposit ion (F ig. 8- 27), rat her t han t he t ube c logging w it h f ibrin or debris. A

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1269

8 - Pleura, Chest Wall, and Diaphragm persist ent air leak may be doc ument ed t o be c aused by inadv ert ent lung punc t ure by t he t ip of t he t ube. Pot ent ial impending injury P.583 may be signaled by not ing t he t ube t ip direc t ly against t he mediast inum and it s c ont ained v essels. Saf e insert ion of a t horac ost omy t ube int o c ert ain

areas, suc h as t he post erior c ost ophrenic rec ess, may be bet t er ensured. T he radiologist c an use CT t o direc t ly guide plac ement of drainage c at het ers, w hic h generally c an be remov ed af t er sev eral day s w hen drainage c eases, t he c av it y c loses, t he pat ient def erv esc es, and t he w hit e blood c ell c ount ret urns t o normal. T he pleural surf ac es hav e a remarkable c apac it y t o heal and an unc omplic at ed pleural peel of t en resolv es f ollow ing c at het er drainage (354). In addit ion t o pleural drainage t ubes, ot her malposit ioned support dev ic es or f oreign bodies also c an be ac c urat ely loc alized by CT (F igs. 8- 28 and 8- 29).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1270

8 - Pleura, Chest Wall, and Diaphragm F igure 8- 21 Lung absc ess. A, B: Chest radiograph show s a f oc al opac it y in t he post erior right low er hemit horax. T he ill- def ined borders suggest a parenc hy mal proc ess, w hile t he peripheral loc at ion and oblong shape raise c onsiderat ion of a pleural c ollec t ion and possible empy ema. C : Cont rast -

enhanc ed CT sc an rev eals a rounded, c av it ary lesion hav ing ac ut e angles w it h t he c hest w all, and surrounding c onsolidat ion, result ing f rom a lung absc ess.

Chronic Empyema Improper t reat ment of an empy ema usually result s in progressiv e organizat ion of t he f ibrin lining t he v isc eral and pariet al pleura surrounding t he loc ulat ed pleural f luid. T he c onsequent t hic kened inelast ic membrane t raps t he lung and c ont rac t s t he hemit horax. T he pleura may ev ent ually c alc if y , part ic ularly if t he c ause of t he empy ema w as t uberc ulous inf ec t ion (208). Suc h a c hronic proc ess is of t en ac c ompanied by an inc rease in t he amount of ext rapleural f at (507). Wit h c hronic t uberc ulous empy ema (243), int ermediat e at t enuat ion in t he ext rapleural spac e may be seen, w hic h c orresponds t o granulomas or c ollagen w it h inf lammat ory c ells and v essel prolif erat ion. In addit ion, a lay er of low at t enuat ion c orresponding t o c aseat ion nec rosis may be seen bet w een t he c ollagenous f ibrous lay ers of t he pariet al pleural peel in t uberc ulous disease. Neit her c alc if ic at ion nor f ibrosis in c hronic empy ema indic at es quiesc ent disease, how ev er, and t he presenc e of f luid in t he pleural rind may be sec ondary t o an ac t iv e ongoing inf ec t ion. Onc e f ibrosis of t he pleural surf ac es has oc c urred, ef f ec t iv e t herapy requires surgic al pleural P.584 dec ort ic at ion. Serial CT c an be used t o det ermine t he need f or dec ort ic at ion (354). In t uberc ulosis, f ibrot horax w it hout pleural ef f usion suggest s inac t iv e disease (242). Sev eral malignanc ies hav e been report ed in assoc iat ion w it h c hronic empy emas. T he most c ommon is ly mphoma, f ollow ed by squamous c ell c anc er, mesot helioma, and v arious sarc omas (323). CT or MRI should be c onsidered t o look f or a mass or c hest w all inv asion w hen radiographs or sy mpt oms suggest t hat an underly ing malignanc y may be present .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1271

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 22 Lung absc ess. A: CT image show s a t hic kened w all w it h irregularly t hic kened int ernal margins. Gas and a small amount of f luid in t he lesion indic at e endobronc hial drainage. B, C : Sagit t ally ref ormat t ed images also show w all t hic kening w it h int ernal irregularit y . Not e t hat bronc hi approac h t he margins of t he lesion, but are not displac ed or dist ort ed. A, ant erior.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1272

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 23 Empy ema. Cont rast - enhanc ed CT sc an show s large f luid c ollec t ion w it h enhanc ement of t hic kened pariet al pleura and adjac ent c ompressed lung.

PLEURAL THICKENING Pleural t hic kening may be f oc al or dif f use, and is usually t he result of a prec eding inf lammat ory or inf ec t ious proc ess. Apic al lung f ibrosis and adjac ent pleural t hic kening is c ommonly seen as a senesc ent c hange, possibly relat ed t o t he relat iv e isc hemia of t his region, or as a result P.585 of prior granulomat ous inf ec t ions suc h as t uberc ulosis or hist oplasmosis. Ext ensiv e, c irc umf erent ial f ibrous pleural t hic kening, usually a result of an organizing ef f usion, hemot horax, or py ot horax, is ref erred t o as a f ibrot horax (F ig. 8- 30). T he f ibrous mat erial deposit ed on t he v isc eral pleural lay er may rest ric t v ent ilat ory exc ursion and reduc e lung v olumes, and f requent ly c alc if ies (143). Ot her benign c auses of dif f use pleural t hic kening inc lude prior surgery , t rauma, radiat ion t herapy , asbest os exposure, drug reac t ions, and c ollagen v asc ular diseases.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1273

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 24 Empy ema w it h mult iple loc ulat ions. Mult iple small gas c ollec t ions are assoc iat ed w it h f luid in t he pleural spac e, along w it h enhanc ing pariet al and v isc eral pleural t hic kening, and edemat ous ext rapleural spac e f at .

F igure 8- 25 Empy ema w it h lung absc ess. Cont rast - enhanc ed CT sc ans show a large empy ema spac e (E) c ont aining an air–f luid lev el and a small f oc us of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1274

8 - Pleura, Chest Wall, and Diaphragm

low at t enuat ion w it hin t he adjac ent c ompressed lung c ont aining f luid and gas, c onsist ent w it h a c onc omit ant lung absc ess (ar r ow ).

Chronic pleural proc esses c harac t erist ic ally produc e expansion of t he adjac ent ext rapleural f at lay er. Great er densit y w it hin t he f at suggest s an ac t iv e pleural proc ess. Malignant neoplasms, inc luding met ast ases, mesot helioma, and ly mphoma, also c an present as t hic kened pleura (283). When nodularit y , a t hic kness ov er 1 c m, c irc umf erent ial pleural t hic kening, or mediast inal pleural inv olv ement are seen, a malignant et iology should be suspec t ed (199,283,317,339). T uberc ulous pleurisy , w hic h c an inv olv e t he mediast inal pleura w hen ext ensiv e, P.586 P.587 is t he main exc ept ion t o t his rule (199,339). Perc ut aneous biopsy w it h CT guidanc e c an be usef ul in det ermining t he c ause of dif f use pleural t hic kening. Using a c ut t ing needle subst ant ially improv es t he diagnost ic y ield ov er t hat of f ine- needle aspirat ion f or c y t ology , as t he f ormer reduc es sampling errors and prov ides a t issue c ore f or immunohist oc hemic al st aining and ult rast ruc t ural st udies (439).

F igure 8- 26 Inf ec t ed bulla. A: CT image rev eals a rim- enhanc ing mass or f luid c ollec t ion ant eriorly , simulat ing an empy ema or ant erior mediast inal mass, and a small right pleural ef f usion lay ering dependent ly . B: CT image obt ained at t he same lev el 1 mont h earlier rev eals t hat t he f luid c ollec t ion in (A) has dev eloped w it hin a preexist ing t hin- w alled bulla at t he same loc at ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

8 - Pleura, Chest Wall, and Diaphragm

1275

F igure 8- 27 Malposit ioned c hest t ube. A, B: Cephaloc audal CT images show a c hest t ube (ar r ow s) plac ed f or empy ema drainage c oursing f rom inf erior (B) t o superior (A) w it hin t he c hest w all.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1276

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 28 Misplac ed c at het ers. A: Nonc ont rast CT image in an 85- y ear- old w oman w it h end- st age renal disease, obt ained af t er insert ion of a nonf unc t ional dialy sis c at het er and radiographic det ec t ion of a rapid inc rease in right pleural ef f usion size, show s t he c at het er in t he right pleural spac e (ar r ow ). T he pleural f luid c ollec t ion is het erogeneously high in at t enuat ion, c onsist ent w it h a hemot horax. Not e pac emaker lead ent ering t he superior v ena c av a (ar r ow head) and low er at t enuat ion lef t pleural ef f usion. B, C : In a 78- y ear- old man 1 day af t er c oronary by pass surgery , an ext rav asc ular c at het er (ar r ow ) bet w een t he right subc lav ian art ery and anot her c at het er in t he right brac hioc ephalic v ein are assoc iat ed w it h t he dev elopment of a large pleural ef f usion result ing f rom t he administ rat ion of f luids t hrough t he misplac ed c at het er. High at t enuat ion dependent f luid lev el (ar r ow heads in C)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1277

8 - Pleura, Chest Wall, and Diaphragm is c onsist ent w it h a small amount of blood. Not e passiv e at elec t asis of right low er lobe, pulmonary art ery c at het er, and c hest w all gas.

F igure 8- 29 F oreign body in t he pleural spac e. A, B: Post operat iv e radiographs af t er c oronary by pass surgery rev eal a met allic objec t (ar r ow ) in t he post erior lef t t horac oabdominal region. Small bilat eral pleural ef f usions and barium c ont rast in t he desc ending c olon are present . C : CT show s t hat t he objec t is loc at ed w it hin t he pleural spac e, w hic h c ont ains a small ef f usion. A ret ained bulldog c lamp w as ret riev ed t horac osc opic ally .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1278

8 - Pleura, Chest Wall, and Diaphragm F igure 8- 30 F ibrot horax. A, B: Dif f use, smoot h pleural t hic kening sparing t he mediast inal surf ac e in a 34- y ear- old man w it h nonrelent ing c hest pain prov ed t o be due t o f ibrosis and c hronic inf lammat ion on biopsy . Dec ort ic at ion w as perf ormed, w it h no malignanc y ident if ied. T he c ause w as undet ermined.

P.588 Adhesions bet w een t he v isc eral and pariet al pleura may f orm bec ause of inf lammat ory or malignant pleural disease. Pleural adhesions c an make open or t horac osc opic t horac ic surgery dif f ic ult , and inc rease operat iv e morbidit y . Pleural t hic kening great er t han 3 mm, high at t enuat ion or enhanc ing bands in pleural f luid or c rossing a pneumot horax, pleural f luid loc ulat ion, subpleural int erst it ial disease w it h v isc eral pleural ret rac t ion or pleural t hic kening, and t he split pleura sign are f indings t hat suggest t he presenc e of adhesions, but hav e been f ound t o be only moderat ely sensit iv e and spec if ic (305). When pleural t hic kening is present , t he v isc eral and pariet al pleura are not nec essarily f used, and adhesions may be present ev en w hen t he pleural margins appear normal.

Pleural Calcification Pleural c alc if ic at ion is most c ommonly seen in plaques as t he result of asbest os exposure, but it also may be a result of prior inf ec t ion or hemorrhage, and usually is assoc iat ed w it h pleural t hic kening (142). Alt hough oblique radiographs inc rease t he sensit iv it y f or det ec t ing pleural plaques (29), large c alc if ied plaques c an simulat e parenc hy mal disease and present a c onf using appearanc e on c hest radiographs. CT c an c learly demonst rat e t he ext ent and c harac t erist ic s of t he pleural disease and rev eal t he t rue nat ure of obsc ured or simulat ed lung disease. Bilat eral, sy mmet ric disease, part ic ularly w it h c alc if ied plaques on t he diaphragm, is almost pat hognomonic of asbest osrelat ed pleural disease (F ig. 8- 31). T alc osis and Bakelit e- and mic a- relat ed pneumoc onioses also c an produc e c alc if ied pleural disease. Pleural c alc if ic at ion is relat iv ely spec if ic f or benign disease, and is bet t er depic t ed by CT t han MRI (199,514).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1279

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 31 Asbest os- relat ed pleural plaques. Ext ensiv ely c alc if ied pleural plaques are seen, relat iv ely sy mmet ric , inv olv ing t he post erior paraspinal and diaphragmat ic pleura (ar r ow heads). A small, nonc alc if ied plaque (ar r ow ) is also present . T he assoc iat ed abundant ext rapleural f at (f ) is c harac t erist ic of a c hronic pleural proc ess.

F igure 8- 32 T alc pleurodesis. T he dense linear opac it y t rac king along t he int erf ac e of t he right c hest w all and lung (ar r ow s) is t he result of a prev ious t alc poudrage. T here is ext ensiv e assoc iat ed c onsolidat ion (c ) in t he right low er lobe and a small loc ulat ed pleural ef f usion (Ef ) ant eriorly .

Unilat eral plaques or t hic kening w it h c alc if ic at ion suggest a prior hemot horax, empy ema, or possibly pleurodesis, in w hic h c ase t he apparent

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1280

8 - Pleura, Chest Wall, and Diaphragm “ c alc if ic at ion” may in f ac t represent t alc (F ig. 8- 32). A prior t uberc ulous empy ema may c ause dense unilat eral pleural t hic kening w it h ext ensiv e c alc if ic at ion (F ig. 8- 33) and is of t en ac c ompanied by subst ant ial assoc iat ed parenc hy mal disease and v olume loss. Pleural c alc if ic at ions alone probably hav e no det ec t able ef f ec t on lung v olumes or pulmonary f unc t ion, but ext ensiv e pleural t hic kening c an result in impaired P.589 pulmonary f unc t ion (143,273,321,440). Hy perc alc emia f rom panc reat it is and sec ondary hy perparat hy roidism in pat ient s w it h c hronic renal f ailure c an oc c asionally c ause pleural c alc if ic at ions, w hic h may inv olv e t he diaphragm

(66). Also, high- densit y (about 160 HU) areas of pleural t hic kening may oc c ur in pat ient s undergoing amiodarone t herapy (259); c onc omit ant ly inc reased liv er densit y should suggest t he proper diagnosis.

F igure 8- 33 Dif f use pleural c alc if ic at ions and t hic kening result ing f rom an old, healed, t uberc ulous empy ema. Calc if ied ly mph nodes are present adjac ent t o t he right int erlobar bronc hus. Not e mild v olume loss on t he af f ec t ed side. T here is mild lef t pleural t hic kening and f luid in t he peric ardial rec esses.

Extrapleural Fat A v ary ing amount of ext rapleural f at is present in most pat ient s, orient ed along t he long axis of t he post erior f ourt h t hrough eight h ribs (431,504). It is loc at ed just out side t he pariet al pleura int ernal t o t he endot horac ic f asc ia

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1281

8 - Pleura, Chest Wall, and Diaphragm

lining t he t horac ic c av it y (14,168,213). Abundant ext rapleural f at deposit ion in obese indiv iduals c an simulat e pleural t hic kening on c hest radiographs. Ext rapleural f at is t y pic ally smoot h, sy mmet ric , t hic kest ov erly ing t he lung apex and mid- hemit horax, and usually is assoc iat ed w it h generalized f at deposit ion in t he mediast inum and subc ut aneous t issues (14). Alt hough oc c asionally c ausing unc ert aint y on c hest radiographs, t hese f eat ures and t he c harac t erist ic densit y of f at c ompared w it h t he great er densit y of plaques are w ell demonst rat ed on CT (F ig. 8- 34) (137). Expansion of t he ext rapleural f at lay er may oc c ur as a reac t ion t o benign pleural inf lammat ion. T he f inding of inc reased ext rapleural f at w it h abnormal pleural t hic kening st rongly f av ors a benign et iology f or t he pleural t hic kening (317).

Asbestos-Related Benign Pleural Processes Persons exposed t o asbest os dust hav e a subst ant ially higher inc idenc e of pleural plaques, t hic kening, ef f usions, pulmonary f ibrosis, and malignant neoplasms of t he lung and pleura (138,142,184,222,247,406,496). Ef f usions are probably t he earliest manif est at ion. T hey are t hought t o be unc ommon, and may be asy mpt omat ic , t ransient , and rec urrent (146). T here are no spec if ic diagnost ic f eat ures, so at t ribut ing a pleural ef f usion t o asbest os exposure requires exc lusion of ot her c auses of exudat iv e ef f usions (406).

F igure 8- 34 Ext rapleural f at . Mediast inal w indow set t ing f rom a highresolut ion CT image show s abundant ext rapleural f at (ar r ow s). T his t y pic ally

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1282

8 - Pleura, Chest Wall, and Diaphragm appears as sy mmet ric pleural t hic kening on c hest radiographs.

T he pleural inf lammat ion c aused by asbest os exposure primarily inv olv es t he pariet al pleura and generally spares t he v isc eral pleura. T he pleural f ibrosis assoc iat ed w it h asbest os f iber inhalat ion may result in dif f use pleural t hic kening or, more c ommonly , f oc al plaque f ormat ion, w hic h is t he most f requent manif est at ion of asbest os exposure (F ig. 8- 35) (8,179,314). A pleural plaque is not a disease but rat her a manif est at ion or hallmark of prior asbest os exposure, pleural inf ec t ion, or ot her disease proc ess. T he lat ent period bet w een t he init ial asbest os exposure and radiologic demonst rat ion of plaques is approximat ely 20 y ears. T he c umulat iv e asbest os exposure and t ot al plaque surf ac e area appear t o be unrelat ed (496). Pleural plaques hav e lit t le or no ef f ec t on lung f unc t ion (90,496). T hey do not undergo malignant degenerat ion, but t hey signif y exposure t o asbest os and suggest an inc reased risk f or t he dev elopment of lung c anc er and malignant mesot helioma (201), and possibly int erst it ial lung disease. Dif f use pleural t hic kening result ing f rom asbest os exposure may impair lung f unc t ion signif ic ant ly (90,236,462). Pleural plaques are c omposed of hy alinized c ollagen in t he submesot helial lay er of t he pariet al pleura and are ac t ually ext rapleural. T hey hav e sharp margins and range in t hic kness f rom 2 mm t o 15 mm (F ig. 8- 36) (314). Alt hough t hey may be unilat eral, asbest os- relat ed pleural plaques are t y pic ally bilat eral. T hey are c lassic ally desc ribed as being P.590 f ound in t he parav ert ebral and post erolat eral regions in t he midport ion of t he c hest bet w een t he f ourt h and eight h ribs, but CT f requent ly rev eals ant erior pleural plaques also. A 1- mm t o 2- mm- t hic k sof t t issue lay er, represent ing t he “ int erc ost al st ripe,” normally may be seen at t he int erc ost al spac es on t hin- sec t ion CT (213). How ev er, any sof t t issue lay ers int ernal t o ribs or in t he parav ert ebral regions are c onsidered abnormal and represent at iv e of pleural plaques (312). Plaques also may oc c ur w it hin t he pariet al pleura ov erly ing t he mediast inum, diaphragm, and peric ardium.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1283

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 35 Asbest os- relat ed plaques. F oc al sof t t issue at t enuat ion plaques (ar r ow s) w it hout c alc if ic at ion in bot h hemit horac es. No ev idenc e of asbest osis w as seen on high- resolut ion CT images.

F igure 8- 36 Asbest os- relat ed pleural plaques. Mult iple c alc if ied and nonc alc if ied pleural based plaques (ar r ow s) inv olv ing t he ant erior and post erior aspec t of bot h hemit horac es c an be seen. Not e t he exophy t ic c omponent of t he plaque along t he right ant erior c hest w all (long ar r ow ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1284

8 - Pleura, Chest Wall, and Diaphragm

Asbest os- relat ed plaques may be of sof t t issue at t enuat ion (F igs. 8- 35 and 837), c omplet ely c alc if ied (see F ig. 8- 31), or part ially c alc if ied (see F ig. 8- 36). Calc if ic at ion w it hin t he plaques is c ommon, seen in 85% of pleural plaques upon hist ologic examinat ion, in about 60% on CT , and in 10% on c onv ent ional radiography . Calc if ic at ion may be punc t at e, linear or “ c ake- like,” espec ially along t he diaphragmat ic surf ac e of t he pleura, w here t hey are almost pat hognomonic of prior asbest os exposure. T he c alc if ic at ion t y pic ally predominat es in t he c ent er of t he plaque. Calc if ied and nonc alc if ied plaques f requent ly c oexist . Asbest os exposure also c an result in dif f use pleural t hic kening (F ig. 8- 38), any w here f rom t he apex t o t he base, as t he result of c onf luent plaques, ext ension of pulmonary f ibrosis t o t he pleura, or an exudat iv e reac t ion f rom a benign asbest os- relat ed ef f usion (8,314,406). Unlike pleural plaques, t his radiologic appearanc e is nonspec if ic . T he f ibrosis usually inv olv es bot h t he pariet al and v isc eral pleura, enc asing t he lung in a dense rind. When ext ensiv e, marked rest ric t iv e lung disease may be produc ed (228). Visc eral pleural t hic kening is indist inguishable f rom pariet al pleural t hic kening, exc ept w hen it is seen in t he int erlobar f issures or w hen t he pleural lay ers are separat ed by f luid. In general, how ev er, v isc eral pleural inv olv ement , part ic ularly w it hin t he f issures, is unc ommon and should raise t he suspic ion of a mesot helioma (394). A pleural ef f usion may be t he harbinger of a malignant pleural or pulmonary neoplasm in a pat ient w it h subst ant ial asbest os exposure, and t his should be t he init ial c onsiderat ion. How ev er, a pleural ef f usion relat ed to P.591 asbest os exposure may be benign in nat ure; it is t y pic ally an exudat e and may be hemorrhagic (117).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1285

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 37 Asbest os- relat ed pleural t hic kening and plaques. Ext ensiv e sof t t issue t hic kening is seen along t he lef t lat eral c hest w all (ar r ow heads). Not e also t he small plaques inv olv ing t he mediast inal pleura adjac ent t o t he lef t heart border and along t he paraspinal regions (ar r ow s).

F igure 8- 38 Asbest os- relat ed dif f use pleural t hic kening. Circ umf erent ial, relat iv ely smoot h pleural t hic kening (ar r ow s) is present , c ont aining some f oc i

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1286

8 - Pleura, Chest Wall, and Diaphragm of c alc if ic at ion lat erally , w it h sparing of t he mediast inal pleura. A marked reduc t ion in t he v olume of t he right hemit horax is present as a result of t he rest ric t ion c aused by t he pleural t hic kening. An assoc iat ed small right pleural ef f usion is present , as w ell as c onc omit ant t hic kening of t he ext rapleural f at (f ), c harac t erist ic of a c hronic pleural proc ess. Minimal c ont ralat eral pleural t hic kening (ar r ow heads) and ext rapleural f at (f ) are present .

Chest radiography has been t he primary means of det ec t ing pleural and lung parenc hy mal c hanges result ing f rom asbest os exposure. CT is f ar more ac c urat e t han radiography , espec ially in depic t ing inv olv ement of t he mediast inal and parav ert ebral pleura (137,496). How ev er, CT has been used primarily f or problem solv ing, suc h as t o dist inguish pleural plaques f rom lung nodules or t o det ermine w het her t he observ ed pleural- based c hanges are t he result of plaques, ext rapleural musc les, or abundant ext rapleural f at (130,137,431). High- resolut ion CT is ev en more def init iv e t han c onv ent ional CT in depic t ing asbest os- relat ed pleural disease (1,2,137,298). Low - dose mult idet ec t or sc anning prov ides ac c urat e ev aluat ion of asbest os- relat ed pleuropulmonary disease, and it s possible use as a f irst - line modalit y has been suggest ed (402). Normal anat omic st ruc t ures, suc h as t he phrenic bundles (F ig. 8- 39) or int erc ost al v eins (F igs. 8- 40 and 8- 41), should not be mist aken f or small pleural plaques. Peripheral pulmonary disease and, oc c asionally , a proc ess inv olv ing t he spine c an ext end int o t he paraspinal sof t t issues and present on CT as pleural disease (F igs. 8- 42, 8- 43, 8- 44). CT is f ar superior t o radiography in det ermining w het her t here is assoc iat ed int erst it ial lung disease, and it c an also be benef ic ial in dist inguishing f oc al plaques f rom int raparenc hy mal nodules, suc h as a possible c arc inoma or ev en a c omplic at ing mesot helioma. CT c an usually det ermine w het her t horac ic masses are pulmonary , mediast inal, pleural, or a c ombined benign pleuroparenc hy mal proc ess suc h as rounded at elec t asis. T he t erm “ asbest osis” is reserv ed f or t he pulmonary parenc hy mal f ibrosis c aused by asbest os exposure and should not be used t o desc ribe asbest os- relat ed pleural abnormalit ies. Alt hough t here is a c orrelat ion bet w een t he sev erit y of pleural disease and presenc e of asbest osis, most pat ient s w it h plaques do not hav e int erst it ial pulmonary disease (1,2). MRI using high- resolut ion pulse sequenc es and radial k- spac e sampling also ac c urat ely depic t s asbest osinduc ed pleural c hanges, w it h int erobserv er agreement c omparable w it h t hat f ound w it h CT (514). How ev er, MRI play s lit t le role in ev aluat ing asbest os-

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1287

8 - Pleura, Chest Wall, and Diaphragm

relat ed pleural disease, t hough it may aid in det ermining t he ext ent of possible malignanc y .

F igure 8- 39 Right phrenic bundle. T he small nodular opac it y along t he pleural surf ac e (ar r ow ) adjac ent t o t he right at rium enhanc es bec ause of t he v essels ac c ompany ing t he phrenic nerv e. T his should not be mist aken f or a pleural plaque, pulmonary nodule, or peric ardial ly mph node.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1288

8 - Pleura, Chest Wall, and Diaphragm F igure 8- 40 Normal int erc ost al v eins. Cont rast - enhanc ed CT sc an demonst rat ing normal int erc ost al v eins (ar r ow heads) in t he paraspinal ext rapleural f at ; t he v ein on t he right side c an be seen ent ering int o t he azy gos v ein (ar r ow ). T hese should not be mist aken f or pleural t hic kening or plaques.

Rounded Atelectasis Rounded at elec t asis is a unique f orm of peripheral pulmonary c ollapse t hat may simulat e a bronc hogenic c arc inoma (111,310,406). It usually oc c urs on t he post erior surf ac e of a low er lobe and is alw ay s assoc iat ed w it h adjac ent pleural t hic kening (111,310). Possible mec hanisms inc lude t he f ormat ion of adhesions ov er t he pleural surf ac e w hen t he lung is at elec t at ic in t he presenc e of an exudat iv e pleural ef f usion, prev ent ing t he lung f rom reexpanding w hen t he ef f usion resolv es, and pleurit is w it h loc alized f ibrosis, w hic h leads t o c ont rac t ion and f olding of t he v isc eral pleura w it h c ollapse of underly ing lung parenc hy ma (34). Pat ient s usually are asy mpt omat ic , and t he f inding is of t en disc ov ered inc ident ally on c hest radiography or somet imes a CT examinat ion perf ormed f or ot her reasons. Rounded at elec t asis is most c ommonly assoc iat ed w it h prior asbest os exposure but may P.592 be seen as a result of t uberc ulosis or ot her c auses of an exudat iv e pleural reac t ion (e.g., post t rauma, post c ardiac surgery ) (85).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1289

8 - Pleura, Chest Wall, and Diaphragm F igure 8- 41 Right superior int erc ost al v ein. Unenhanc ed A: and enhanc ed B: CT images in t w o dif f erent pat ient s show normal loc at ion and appearanc e of right superior int erc ost al v ein (ar r ow s), w hic h may simulat e a pleural nodule. T he v asc ular nat ure of t he st ruc t ure usually c an be rec ognized by t rac ing it on c onsec ut iv e sc ans, t hough it may not be w ell dist ended t hroughout it s c ourse.

Rounded at elec t asis t y pic ally appears as a rounded or ov al mass, v ariable in size but usually around 3 c m t o 5 c m in diamet er, f orming an ac ut e angle w it h t he pleura (see F igs. 7- 76 and 7- 77) (111,310,325). T he mass may c ont ain air bronc hograms or c ent ral luc enc y as a result of slight ly aerat ed at elec t at ic lung parenc hy ma (403). A c harac t erist ic f inding on CT , also desc ribed f or MRI, is t he ident if ic at ion of c urv ed bronc hi and v essels ent ering t he mass at t he edge c losest t o t he hilum, produc ing a “ c omet t ail” appearanc e (310,502,529). T he adjac ent lung may demonst rat e c ompensat ory hy perinf lat ion, and t here may be ot her signs indic at iv e of v olume loss (34). Oc c asionally , small subpleural c urv ilinear st reaky opac it ies may be seen adjac ent t o c hronic pleural t hic kening, w hic h likely represent an inc omplet e f orm of rounded at elec t asis (F igs. 8- 45, 8- 46, 8- 47). T hough MRI is not usually indic at ed, it may bet t er separat e t he hy point ense band of t hic kened pariet al pleura f rom t he at elec t at ic mass on T 2- w eight ed images (529). Homogeneous enhanc ement w it h gadolinium is seen. MRI also more f requent ly rev eals hy point ense or unenhanc ing lines w it hin t he at elec t at ic mass, t hought t o represent inf olded v isc eral pleura, t hough t he spec if ic it y of t his f inding is unc ert ain (529).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1290

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 42 Ly mphoma. Paraspinal pleural- based sof t t issue at t enuat ion mass (ar r ow heads).

F igure 8- 43 Ost eomy elit is. Dest ruc t ion and sc lerosis of t he T - 11 v ert ebral body is seen along w it h inf lammat ory c hanges t hat t hic ken t he paraspinal sof t t issues (ar r ow s), displac ing t he diaphragmat ic c rura lat erally .

F igure 8- 44 Ext ramedullary hemat opoiesis. Bilat eral paraspinal sof t t issue masses (ar r ow s) in a w oman w it h sic kle c ell anemia. L, lef t lobe of t he liv er.

P.593 T here is usually lit t le c hange w it h t ime, if any , alt hough resolut ion has been report ed (111); in one c ase, w e observ ed rapid resolut ion f ollow ing a pneumot horax induc ed by perc ut aneous needle biopsy . F or equiv oc al c ases in

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1291

8 - Pleura, Chest Wall, and Diaphragm w hic h t he dist inc t ion bet w een rounded at elec t asis and a lung t umor is

dif f ic ult , f luorodeoxy gluc ose posit ron emission t omography may prov e usef ul. A high spec if ic upt ake v alue w ould support perf orming a biopsy f or diagnosis; low upt ake w ould support c lose observ at ion by serial f ollow - up CT sc anning. Perc ut aneous needle biopsy f or t issue ev aluat ion may be required t o help c orroborat e t he diagnosis and should be c onsidered in equiv oc al c ases (34,310), t hough pat hologic int erpret at ion may be dif f ic ult (260). When rounded at elec t asis oc c urs in assoc iat ion w it h a pleural ef f usion or f oc al pleural mass, rat her t han simple pleural t hic kening, t he possibilit y of malignant mesot helioma should be c onsidered (341).

F igure 8- 45 Asbest os- relat ed pleuroparenc hy mal c hanges. A: Chest radiograph show s some linear opac it ies in t he lung adjac ent t o some pleural t hic kening along t he low er lef t lat eral c hest w all. B: High- resolut ion CT demonst rat es pleural t hic kening (ar r ow s) and adjac ent nodular and linear opac it ies (ar r ow heads) c ompat ible w it h small areas of rounded at elec t asis (“ round at elec t asis equiv alent s” ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1292

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 46 Asbest os- relat ed pleuroparenc hy mal c hanges. A, B: Mediast inal and lung w indow set t ings, at slight ly dif f erent lev els, show pleural t hic kening (ar r ow s) post eriorly and abundant ext rapleural f at (f ). A “ mass” (m) w it h adjac ent c onv erging v essels abut s t he t hic kened pleura on t he lef t , in a c harac t erist ic paraspinal loc at ion, represent ing rounded at elec t asis. T here are similar but less w ell- def ined c hanges (open ar r ow s) (“ round at elec t asis equiv alent s” ) in t he right paraspinal region.

P.594

PNEUMOTHORAX Alt hough c onv ent ional c hest radiography is t he princ ipal t ec hnique f or det ec t ing and ev aluat ing pneumot horac es, CT c an be helpf ul in c omplex c ases and in v ery selec t ed c ases w hen erec t or dec ubit us f ilms c annot be obt ained. CT may be usef ul in dif f erent iat ing a large bulla f rom a pneumot horax suspec t ed on a c onv ent ional radiograph and f or assessing adequac y of c hest t ube posit ioning, part ic ularly f ollow ing emergent t horac ost omy or w it h persist ent pleural f luid c ollec t ions (F ig. 8- 48) (30,43,55,71,258). CT also may be v aluable in c harac t erizing c onf using paramediast inal air c ollec t ions as w ell as in dist inguishing a medial pneumot horax f rom a pneumomediast inum or a parenc hy mal pneumat oc ele. CT may be helpf ul t o ev aluat e f or a c oexist ent pneumot horax w hen ext ensiv e subc ut aneous air obsc ures f indings on c hest radiographs. Ident if ic at ion of ev en a small pneumot horax c an be import ant in t rauma pat ient s about t o undergo mec hanic al v ent ilat ion or general anest hesia f or surgery . F or t his reason, and t he rec ognized low sensit iv it y of supine port able radiographs, t he most c ephalad sc ans of all abdominal CT examinat ions

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1293

8 - Pleura, Chest Wall, and Diaphragm obt ained during t rauma ev aluat ion should be examined w it h lung w indow set t ings t o ident if y an ot herw ise oc c ult pneumot horax (F ig. 8- 49) (508). A primary spont aneous pneumot horax c an oc c ur in ot herw ise healt hy indiv iduals P.595 in t he absenc e of a know n t raumat ic ev ent . T hese oc c ur more f requent ly in

t all, t hin males in t heir t hird t o f ourt h dec ades, of t en as a result of rupt ure of subpleural blebs. CT may be usef ul in det ec t ing apic al subpleural blebs, bullae, and parasept al emphy semat ous lesions, w hic h may w arrant resec t ion t o prev ent rec urrenc es (103,282). How ev er, v isc eral pleural def ec t s may not be v isible. T here are numerous ot her c auses or predisposing c ondit ions f or pneumot horax, inc luding perc ut aneous int erv ent ions, t horac ic surgery , barot rauma f rom mec hanic al v ent ilat ion, c y st ic f ibrosis, hist ioc y t osis X, ly mphangioleiomy omat osis, pneumonia, malignanc y , and rarely , endomet rial pleural implant s (c at amenial pneumot horax) (F ig. 8- 50).

F igure 8- 47 Asbest os- relat ed plaques and rounded at elec t asis. A, B: Mediast inal and lung w indow set t ings demonst rat e a st ellat e mass (m) in t he lef t upper lobe adjac ent t o marked pleural t hic kening (ar r ow s), w it h v olume loss indic at ed by subst ant ial ant erior displac ement of t he lef t major f issure, c harac t erist ic of rounded at elec t asis. Less w ell- f ormed at elec t asis is present in t he right upper lobe (ar r ow heads), also adjac ent t o t hic kened pleura. Small pleural plaques and t hic kening are present post eriorly on bot h sides. No int erst it ial f ibrosis t o suggest asbest osis is ident if ied.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1294

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 48 Chest t ube (ar r ow ) in t he lef t major f issure (ar r ow head). A small lef t pneumot horax (P) and residual c hy lous pleural ef f usion (Ef ) persist in a 43- y ear- old w oman w it h ly mphangioleiomy omat osis.

Persist ent air leaks, w het her loc ulat ed or not , raise suspic ion of a malposit ioned c hest t ube or a bronc hopleural f ist ula. Chest t ube posit ion is readily and more ac c urat ely det ermined by CT t han by c hest radiography . Chest t ubes not w it hin t he pleural spac e (int raparenc hy mal or in t he c hest w all) need t o be replac ed or reposit ioned. Whet her t ubes in t he int erlobar f issures prov ide adequat e drainage of pneumot horax or pleural ef f usions has been c ont rov ersial (71,258). Oc c asionally , int raf issural t horac ost omy drainage t ubes may appear int raparenc hy mal on CT , part ic ularly w hen t hic ker sec t ions are obt ained, or w hen t he t ube is in t he minor f issure (71). T ubes in t he minor f issure should be loc at ed inf erior t o t he ant erior and post erior upper lobe segment al bronc hi and superior t o t he middle lobe segment al bronc hi. A t horac ost omy t ube may go more post eriorly t han expec t ed if t here is an ac c essory horizont al f issure. In addit ion, c hange in posit ion of a c hest t ube f rom ant erior t o post erior on asc ending t ransv erse images suggest s loc at ion in t he major f issure (71). Bronc hopleural f ist ulae also c an c ause a persist ent pneumot horax, and may be a result of nec rot izing pneumonia (of t en leading t o empy ema), lung resec t ion (F ig. 8- 51), malignanc y , t rauma, barot rauma, bronc hiec t asis, or inf arc t ion. Alt hough t iny openings in t he v isc eral pleural surf ac e may not be ident if iable, CT c an of t en suc c essf ully depic t direc t c ommunic at ion bet w een a peripheral airw ay and t he pleural spac e, and aid in bronc hopleural f ist ula management (520). Ident if ic at ion of a bronc hopleural f ist ula by CT , in t he absenc e of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1295

8 - Pleura, Chest Wall, and Diaphragm peripheral bullae, suggest s a great er likelihood of a need f or surgic al management (405). Persist ent pneumot horax also may oc c ur bec ause of t he f ailure of “ t rapped” lung t o reexpand f ollow ing drainage of a large pleural ef f usion in t he presenc e of pleural malignanc y or pleural t hic kening result ing f rom c hronic empy ema (260).

TUMORS OF THE PLEURA T he most c ommon benign t umors inv olv ing t he pleura are lipomas and loc alized f ibrous t umors. Met ast ases are t he most c ommon f orm of malignanc y inv olv ing t he pleura. P.596 T hey may be of hemat ogenous origin or a result of direc t ext ension, suc h as f rom bronc hogenic c arc inoma, inv asiv e t hy moma, or c hest w all t umors. Primary pleural t umors, suc h as mesot heliomas, ac c ount f or less t han 5% of malignant pleural neoplasms (113).

F igure 8- 49 Basilar pneumot horax in a t rauma pat ient . A: Supine radiograph show s no sign of pneumot horax. B: CT image t hrough lung bases rev eals a small right pneumot horax ant eriorly . T he lac k of displac ement of t he lat eral lung base f rom t he c hest w all explains t he f ailure of radiographic det ec t ion. Parenc hy mal opac it y post eriorly likely represent s mild pulmonary c ont usion and at elec t asis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1296

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 50 Cat emenial pneumot horax. A, B: CT images at t he lev el of t he diaphragm in a 40- y ear- old w oman w ho report ed prev ious c y c lic episodes of c hest pain rev eal a large basilar pneumot horax, small nodules (ar r ow s) on t he diaphragmat ic pleural surf ac e, and a small amount of pleural f luid or blood lay ering dependent ly . T horac osc opic biopsy rev ealed endomet rial implant s, and pleurodesis w as perf ormed.

CT is usef ul in def ining t he loc at ion and ext ent of benign and malignant pleural t umors, and in assessing t he underly ing lung parenc hy ma and pleura in pat ient s w it h a pleural ef f usion. F eat ures of pleural disease f av oring malignanc y ov er a benign proc ess inc lude pleural t hic kening ov er 1 c m, nodularit y , c irc umf erent ial pleural inv olv ement , and mediast inal pleural inv olv ement (199,283,317,339). Def init iv e diagnosis usually requires c y t ologic /hist ologic analy sis. When a large ef f usion is present , perf orming t he CT examinat ion f ollow ing drainage of t he f luid opt imizes assessment of t he underly ing lung (311). MRI may be usef ul in dist inguishing benign f rom malignant pleural lesions. As w it h CT , MRI f eat ures most suggest iv e of pleural malignanc y inc lude mediast inal pleural inv olv ement , c irc umf erent ial pleural t hic kening, nodularit y and irregularit y of t he pleural c ont our, and inf ilt rat ion of t he c hest w all or diaphragm (199). High signal int ensit y relat iv e t o int erc ost al musc les on T 2w eight ed images and on c ont rast - enhanc ed T 1- w eight ed images is anot her MRI f inding P.597 t hat st rongly f av ors malignanc y (199). Bec ause MRI c an help dist inguish f ibrous t issue f rom neoplasm based on signal c harac t erist ic s, it may play a role in det ec t ion of malignanc y arising in c hronic empy ema (323). Signal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1297

8 - Pleura, Chest Wall, and Diaphragm hy point ensit y relat iv e t o skelet al musc le on T 2- w eight ed images may be a reliable indic at or of benign pleural disease (125). Compared w it h CT , MRI is muc h less c apable of depic t ing benign pleural c alc if ic at ion.

F igure 8- 51 Bronc hopleural f ist ula 6 w eeks af t er right upper lobec t omy and w ide right low er lobe w edge resec t ion f or lung c anc er. A: Lat eral radiograph show s t hin- w alled luc enc y (ar r ow s) inf eriorly along t he post erior pleural margin. B: CT rev eals a bronc hopleural f ist ula (ar r ow ) t o a small loc ulat ed pneumot horax, w hic h gradually resolv ed w it hout int erv ent ion. Ret ic ular and small c y st ic c hanges c harac t erist ic of mild parenc hy mal f ibrosis are present peripherally .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1298

8 - Pleura, Chest Wall, and Diaphragm F igure 8- 52 Ext rapleural lipoma. A: Post eroant erior c hest radiograph demonst rat es a pleural based mass (m) along t he lef t lat eral c hest w all w it h

an obt use angle along t he superior margin and a poorly def ined inf erior margin at t he pleural int erf ac e. B: CT show s c harac t erist ic homogeneous f at at t enuat ion.

Benign Tumors Lipoma Benign pleural or ext rapleural lipomas are usually asy mpt omat ic and inc ident al f indings. T hese lesions c an arise f rom subpleural adipose t issue, but t he origin may not be apparent (180). Some lipomas may ext end f rom t he c hest w all int o t he pleural spac e, prot ruding int o t he pleural surf ac e and simulat ing a peripheral pulmonary lesion on radiography (123). CT allow s a def init iv e diagnosis based on t he c harac t erist ic f at at t enuat ion, w hic h is usually homogeneous (F ig. 8- 52) (118). Alt hough a c apsule is somet imes ident if ied and benign lipomas may hav e small bands of f ibrous sof t t issue, a not ably higher at t enuat ion sof t t issue c omponent prev ent s exc lusion of liposarc oma. Liposarc omas are exc eedingly rare and are t y pic ally more het erogeneous in appearanc e, w it h subst ant iv e areas of sof t t issue densit y (F ig. 8- 53). Inf lammat ory c hanges f ollow ing t he inf arc t ion of a lipoma c an produc e a similar appearanc e (F ig. 8- 54). On MRI, lipomas are high in signal on T 1- w eight ed images and int ermediat e in signal on T 2- w eight ed images, are ident ic al t o subc ut aneous f at , and t heir signal c an be nulled on f at - suppression sequenc es.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1299

8 - Pleura, Chest Wall, and Diaphragm F igure 8- 53 Liposarc oma inv olv ing t he pleura. A large inhomogeneous mass

(m) f ills t he ent ire lef t hemit horax w it h mediast inal shif t t o t he right . Areas of f at at t enuat ion (f ) are int erspersed w it h sof t t issue st romal element s.

F igure 8- 54 Inf arc t ed ext rapleural lipoma. A, B: Post eroant erior and lat eral c hest radiographs demonst rat e a 3- c m lef t ant erior pleural- based mass (m). C : CT show s a primarily f at at t enuat ion pleural- based mass (m) w it h c ent ral sof t t issue st roma. T his 66- y ear- old w oman present ed w it h lef t ant erior c hest pain, and t he appearanc e w as c onsidered t o be c ompat ible w it h an inf arc t ed lipoma, alt hough it c ould hav e represent ed a liposarc oma. Conserv at iv e management w as selec t ed, t he c hest pain disappeared, and t he mass diminished subst ant ially in size on f ollow - up c hest radiographs.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1300

8 - Pleura, Chest Wall, and Diaphragm P.598

Fibrous Tumors of the Pleura F ibrous t umors of t he pleura are relat iv ely rare, ac c ount ing f or less t han 5% of all pleural neoplasms, but t hey are t he most c ommon benign pleural t umor (102,489). Rarer t han malignant mesot helioma, f ibrous t umors w ere know n as “ benign mesot helioma” in t he past ; t he name w as c hanged bec ause t hey do not arise f rom t he mesot helial c ells but rat her f rom t he underly ing mesenc hy mal c onnec t iv e t issue (116,196,433), and t hey may not behav e in a benign f ashion. T hey oc c ur w it h nearly equal f requenc y in men and w omen (t here may be a slight f emale predominanc e) and are f ound in pat ient s of all ages, w it h most pat ient s 45 and 65 y ears old (63,180,278,433). T here is no relat ionship t o asbest os exposure (63,278,301). Most f ibrous t umors are asy mpt omat ic and are disc ov ered inc ident ally on rout ine c hest radiographs (102,315). Pat ient s w it h larger t umors may present w it h a c ough, c hest pain, or dy spnea. A small perc ent age of pat ient s exhibit t he c lassic ally assoc iat ed c linic al f indings of hy pert rophic pulmonary ost eoart hropat hy , c lubbing, or sy mpt omat ic hy pogly c emia (63,102,113,301,315); t umor produc t ion of highmolec ular- w eight insulin- like grow t h f ac t or II has been suggest ed as t he c ause of t he lat t er (427). F ibrous t umors of t he pleura usually are indolent and slow grow ing, and hav e been report ed ov er periods as long as 20 y ears (433). In most of t he more rec ent surgic al series, P.599 around 60% t o 70% are report ed as benign (301). Current hist ologic c rit eria f or malignanc y inc lude high c ellularit y , pleomorphism, more t han 4 mit oses per 10 high- pow er f ields, and nec rosis (72,116,301). Bec ause of t he v ariat ion of c ellular and c ollagenous regions, perc ut aneous biopsy may be inadequat e f or def init iv e diagnosis and c lassif ic at ion as benign or malignant . Most f ibrous t umors (about 80%) arise f rom t he v isc eral pleura (53,63,113,116,301). T hey oc c ur slight ly more of t en in t he low er half of t he c hest , w it h no signif ic ant side predilec t ion (53,63). T hese t umors are usually sessile or lobulat ed but some are at t ac hed t o t he pleural surf ac e by a pedic le or st alk. T his allow s mobilit y so t hat t hey may c hange shape on inspirat ion and expirat ion, during f luorosc opy , or bet w een CT examinat ions (102,128,232,315). Demonst rat ion of a pedic le is pat hognomonic and highly suggest iv e of t he benign v ariet y of t he t umor and a f av orable prognosis

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1301

8 - Pleura, Chest Wall, and Diaphragm (63,102,315). Bec ause t hese t umors arise at t he int erf ac e of t he lung and ot her st ruc t ures, t hey may simulat e pulmonary masses suc h as peripheral bronc hogenic c arc inoma, ant erior mediast inal masses suc h as t hy moma, post erior mediast inal masses suc h as neurogenic t umors, or diaphragm abnormalit ies suc h as elev at ion or ev ent rat ion (107). Masses arising in a f issure may simulat e pulmonary nodules on c hest radiographs (113,315,468). CT c an be usef ul in det ermining t he origin and et iology of f ibrous pleural t umors, but t he f eat ures are nonspec if ic . F indings t hat suggest t he diagnosis inc lude a solit ary , sharply def ined, somet imes lobulat ed, sof t t issue, pleuralbased mass w it hout ev idenc e of c hest w all inv asion (F igs. 8- 55, 8- 56). P.600 When t he lesion is in a f issure (F ig. 8- 57) t apering margins may be not ed

(102). T he lesions may grow t o be v ery large, almost f illing a hemit horax (F ig. 8- 58). Alt hough smaller lesions t y pic ally make an obt use angle w it h t he c hest w all, larger lesions usually f orm an ac ut e angle (128,315). When ac ut e angles are present , a smoot hly t apering margin adjac ent t o t he t umor may be seen (102,407). Smaller lesions t y pic ally appear homogeneous, w hile larger lesions may hav e low at t enuat ion areas w it hin t hem bec ause of c y st ic nec rosis or hemorrhage (278,315). T he v asc ularit y , size, and c omposit ion of f ibrous t umors t y pic ally result in enhanc ement t hat may be homogeneous or het erogeneous, equal t o or great er t han t hose of ot her sof t t issues (F ig. 859) (128,278,315,407). As w it h unenhanc ed at t enuat ion, larger lesions t end t o enhanc e more het erogeneously . Enhanc ement is not inv ariable, being observ ed in 62% of c ases in one series (407). A minorit y of f ibrous pleural t umors hav e assoc iat ed pleural ef f usions, w hic h may be more c ommon in t he malignant v ariet y (407). Small f oc i of c alc if ic at ion w it hin f ibrous pleural t umors hav e been seen in up t o 26% of c ases (116,128,407).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1302

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 55 Benign f ibrous t umor of t he pleura. A, B: Chest radiograph show s nonspec if ic large opac it y in post erior right hemit horax simulat ing a diaphragmat ic hernia or ev ent rat ion. C , D: CT sc an rev eals a large, w ellc irc umsc ribed, het erogeneously enhanc ing mass. Ac ut e angles w it h c hest w all make it dif f ic ult t o dist inguish f rom a mass arising in t he lung. A small pleural ef f usion and medially adjac ent at elec t asis are present in (D).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1303

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 56 Benign f ibrous t umor of t he pleura. Small, homogeneous, minimally enhanc ing right paraspinal mass, f orming obt use margins w it h t he c hest w all, prov ed t o be a benign f ibrous pleural t umor. Wit h t his paraspinal loc at ion, a neurogenic t umor also w as a c onsiderat ion.

Wit h MRI, loc alized f ibrous t umors hav e predominant ly low t o int ermediat e but het erogeneous signal int ensit y on T 1- and T 2- w eight ed images, probably bec ause of t he predominanc e of hy poc ellular f ibrous t issue; areas of high signal are more f requent ly present on T 2- w eight ed images, possibly relat ed t o degenerat ion, nec rosis, and hy perc ellular c omponent s (128,407,485). Enhanc ement w it h gadolinium is also het erogeneous and int ense (407,485). Mult iplanar MRI or mult idet ec t or CT w it h mult iplanar ref ormat t ing may be helpf ul in loc alizing t hese masses, and demonst rat ing t heir f ull ext ent and relat ionship t o t he diaphragm or mediast inal st ruc t ures. Rarely , loc alized f ibrous t umors c an inv ade t he c hest w all and c ause bone dest ruc t ion (113,315), or present as mult iple lesions (72). How ev er, t he radiologic appearanc e usually is not reliable f or det ermining w het her an indiv idual lesion w ill behav e in a benign or malignant manner, and surgic al remov al is rec ommended f or all. Obt aining a c omplet e exc ision c onf ers t he best prognosis (72,301,407). Prev ent ing loc al and pot ent ially unresec t able rec urrenc e is t he primary c onc ern, sinc e ext ensiv e int rat horac ic grow t h result ing f rom unresec t able rec urrenc e or lat e diagnosis may be f at al (63). Rec urrenc e c an happen as lat e as 15 y ears af t er resec t ion (315). F ollow - up imaging is adv ised af t er resec t ion t o ev aluat e f or rec urrent disease, w hic h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1304

8 - Pleura, Chest Wall, and Diaphragm

also c an be resec t ed (100,407). Malignant t umors also may rarely met ast asize (63,301,407).

Calcifying Fibrous Pseudotumor Calc if y ing f ibrous pseudot umor of t he pleura is a rare, benign lesion t hat dif f ers f rom loc alized f ibrous t umor of t he pleura (119). Like ot her pseudot umors (129), t hese lesions are t hought t o result f rom prev ious inf lammat ion. T he pleural v ariet y c ont ains ext ensiv e psammomat ous c alc if ic at ion. Solit ary and mult if oc al lesions hav e been report ed. In c ont rast t o loc alized f ibrous t umors of t he pleura, c alc if y ing f ibrous pseudot umors oc c ur in c hildren and y oung adult s. Rec urrenc e f ollow ing resec t ion is rare.

Thoracic Splenosis T horac ic splenosis is t he result of ec t opic splenic t issue displac ed int o t he t horax f ollow ing a diaphragm injury (359,532). T he splenic f ragment s bec ome supplied by t he pleural v essels and present as pleural nodules and masses. T he CT appearanc e (F ig. 8- 60) is nonspec if ic , alt hough t he enhanc ement pat t ern is t y pic al of splenic t issue. A hist ory of appropriat e t rauma and c onc omit ant CT ev idenc e of splenec t omy or perit oneal splenosis should suggest t he diagnosis. Charac t erizat ion of pleural nodules as splenic t issue c an be ac c omplished w it h heat - damaged red blood c ell sc int igraphy , w hic h may be pref erable t o sulf ur c olloid sc int igraphy , as t he lat t er may be f alsely negat iv e (174).

Malignant Tumors Pleural Metastases Met ast ases c onst it ut e t he ov erw helming majorit y of malignant neoplasms inv olv ing t he pleura. Pleural met ast ases usually inv olv e bot h t he v isc eral and pariet al pleural surf ac es, and almost alw ay s c ause an assoc iat ed ef f usion (307), t hought t o be a result of t he impairment of ly mphat ic drainage, inc reased c apillary permeabilit y result ing f rom inf lammat ion, or endot helial disrupt ion (101). Adenoc arc inoma is t he most likely c ell t y pe t o met ast asize t o t he pleura. Lung c anc er, breast c anc er, ly mphoma, and ov arian c anc er t oget her ac c ount f or more t han t hree f ourt hs of pleural met ast ases (194,410).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1305

8 - Pleura, Chest Wall, and Diaphragm Bot h met ast at ic c arc inoma and ly mphoma c an inv olv e t he abundant ly mphat ic c hannels and P.601

ly mphoid aggregat es present just beneat h t he v isc eral pleura. Lung and breast c anc er may inv ade t he pleura by direc t spread. Pleural met ast asis also may oc c ur as a result of hemat ogenous spread f rom t umor emboli lodged in dist al branc hes of t he pulmonary art eries (307). Inv asiv e t hy momas also may inv olv e t he pleura, by direc t ext ension f rom t he ant erior mediast inum, result ing in disc ret e masses or dif f use pleural t hic kening (332,534) T he mediast inal c omponent of t he t umor is not alw ay s large (113).

F igure 8- 57 Benign f ibrous t umor of t he pleura arising in a f issure. A, B: Chest radiograph show s a large mass loc at ed post erior t o t he right hilum. C , D: CT sc an rev eals a het erogeneously enhanc ing mass w it h c omplet ely smoot h margins ext ending t o bot h sides of t he major f issure.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1306

8 - Pleura, Chest Wall, and Diaphragm

Inf ilt rat ion of t he pleural surf ac es usually result s in a pleural ef f usion, w hic h is t he f irst manif est at ion of pleural met ast ases in most c ases. CT may rev eal pleural- based nodules radiographic ally obsc ured by t he pleural f luid (F ig. 861). Oc c asionally , an ef f usion is c onspic uously absent (F ig. 8- 62). Pleural met ast ases usually appear as relat iv ely small, nodular lesions or lent ic ular masses hav ing obt use margins w it h t he c hest w all (F igs. 8- 63 and 8- 64). Pleural implant s also may oc c ur as solit ary lesions along t he c hest w all, mediast inum, diaphragm, or int erlobar f issures (113). As t he disease progresses, nodularit y and pleural t hic kening may enc ase t he lung and ext end int o t he f issures (F igs. 8- 62, 8- 65, and 8- 66). T he sof t t issue c omponent of t en enhanc es f ollow ing c ont rast administ rat ion, allow ing or improv ing dif f erent iat ion f rom any adjac ent nonenhanc ing pleural ef f usion. Anc illary f indings on CT , suc h as mediast inal ly mph node enlargement , lung nodules, rib lesions, or a subc ut aneous mass, support a presumpt iv e diagnosis of pleural met ast ases (see F ig. 8- 64). Alt hough inf lammat ory P.602 pleural diseases, suc h as inf ec t ion or asbest os- relat ed pleural disease, of t en produc e pleural t hic kening, t hey rarely produc e t he nodular and irregular appearanc e of met ast at ic disease. Pleural met ast ases may be dif f ic ult t o dif f erent iat e f rom malignant mesot helioma; bot h may result in pleural ef f usions, isolat ed pleural nodules, dif f use or nodular t hic kening, and, in some c ases, enc asement of t he lung.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1307

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 58 Malignant f ibrous t umor of t he pleura. A: Chest radiograph show s a large sof t t issue opac it y w it hin t he right hemit horax w it h mass ef f ec t on t he heart and mediast inum. B, C : CT sc an rev eals a large, het erogeneously enhanc ing mass displac ing t he mediast inum and heart t o t he lef t and c ompressing t he enhanc ing lung peripherally .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1308

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 59 F ibrous t umor of t he pleura w it h dif f use enhanc ement . CT sc an show s a het erogeneously enhanc ing sof t t issue mass (M) in t he post erior right low er hemit horax. Enhanc ement is slight ly great er t han t hat of musc le and similar t o t hat of liv er (L).

Pleural Lymphoma Bot h Hodgkin and non- Hodgkin ly mphoma c an inv olv e t he pleura. It is seldom t he solit ary init ial manif est at ion of t he disease (25,456), but rat her a result of rec urrenc e, or in addit ion t o t hy mic or mediast inal nodal and somet imes pulmonary parenc hy mal disease. A paraspinal loc at ion (see F ig. 8- 42) is c ommon. Ly mphomat ous inv olv ement of t he ly mphat ic c hannels and ly mphoid aggregat es f ound beneat h t he v isc eral pleura of t he lung may present as subpleural nodules or plaques (350,456). Ly mphoma also may inv olv e t he pleura by direc t ext ension f rom t he mediast inum (311) or c hest w all. T he majorit y of pat ient s P.603 w it h ly mphoma and a pleural ef f usion hav e mediast inal adenopat hy (18,283). Ly mphat ic obst ruc t ion appears t o be t he primary mec hanism in Hodgkin disease, and direc t pleural inf ilt rat ion t he primary mec hanism in non- Hodgkin ly mphoma (423). In addit ion t o nodules and ef f usions (see F ig. 8- 4), areas of pleural t hic kening (F ig. 8- 67) and dif f use pleural inv olv ement (F ig. 8- 68) indist inguishable f rom ot her pleural malignanc ies may be seen, t hough c irc umf erent ial inv olv ement may be less f requent (283). T he pleural disease of t en ext ends t o or f rom t he ext rapleural spac e (18). Pleural inv olv ement in

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1309

8 - Pleura, Chest Wall, and Diaphragm pat ient s w it h ly mphoma may signif ic ant ly af f ec t radiat ion t herapy planning, and unrec ognized disease inc reases t he risk of t reat ment f ailure (73). Leukemic inf ilt rat ion also may c ause pleural t hic kening (241).

F igure 8- 60 Splenosis. A: CT image in a 29- y ear- old man w it h esophageal c anc er and a hist ory of splenec t omy f ollow ing a gunshot w ound rev eals mult iple pleural- based sof t t issue masses on t he lef t . B: Heat - damaged, 99mT ec hnet ium–labeled red blood c ell sc int igraphy rev eals upt ake in t he

mult iple pleural masses, c onsist ent w it h splenic t issue.

Malignant Mesothelioma Mesot helioma is a highly malignant , loc ally aggressiv e t umor of t he pleura assoc iat ed w it h asbest os exposure. T his rare, rapidly grow ing t umor has an ext remely poor prognosis, w it h a median surv iv al somew here in t he range of f our t o eight een mont hs (5). It is t w o t o six t imes more c ommon in men t han in w omen, w it h a peak present at ion in t he sixt h and sev ent h dec ades of lif e (53). Clinic al sy mpt oms are t y pic ally a lat e f inding and inc lude c hest pain, dy spnea, c ough, w eakness, and w eight loss (5,53,167,256). Unlike t he loc alized f ibrous pleural t umor, hy pert rophic pulmonary ost eoart hropat hy and int ermit t ent hy pogly c emia are inf requent w it h malignant mesot helioma, oc c urring in less t han 10% of pat ient s (53). Eight y perc ent of pat ient s present ing w it h malignant mesot helioma hav e had oc c upat ional exposure t o asbest os (80,256,383,517), a link f irst est ablished in 1960 (506). T he inc idenc e of malignant mesot helioma has c ont inued t o inc rease, presumably bec ause of t he w idespread use of asbest os in t he 1950s (167,200) and an av erage lat enc y on t he order of 35 t o 40 y ears or more bet w een exposure and t he dev elopment of mesot helioma (514,533). In t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1310

8 - Pleura, Chest Wall, and Diaphragm Unit ed St at es, it has been est imat ed t hat mesot helioma inc idenc e w ould dec rease af t er t he y ear 2000 (388). How ev er, in Europe, analy sis of mesot helioma deat h rat es among men of dif f erent generat ions suggest s t hat mesot helioma deat hs w ill c ont inue t o inc rease and are likely t o peak in t he y ear 2010 or lat er (207,380). Croc idolit e is t he most c arc inogenic and f ibrogenic f orm of asbest os. Chry sot ile, ant hophy llit e, and t remolit e are relat iv ely more benign.

T he risk of dev eloping mesot helioma is v ery low up t o 15 y ears af t er asbest os exposure but inc reases signif ic ant ly t hereaf t er (269,380) and is higher in t hose w it h great er int ensit y and durat ion of exposure (322). It has not been prov en t hat low lev els of asbest os exposure c ause mesot helioma, but w het her a t hreshold lev el assoc iat ed w it h an inc reased risk exist s is unknow n (322). Persons w it h t he great est risk f or dev elopment of mesot helioma inc lude insulat ion w orkers, shipy ard w orkers, c onst ruc t ion w orkers, w orkers in t he heat ing t rades, and asbest os miners and manuf ac t urers (309). In t he Unit ed St at es, c urrent ly approv ed uses f or asbest os inc lude brake pads, roof ing mat erial, v iny l t iles, c ement pipe and sheet ing, gasket s, and garden produc t s (v ermic ulit e); most is c urrent ly f ound in building and mac hinery insulat ion produc t s and older produc t s like resale applianc es (533). How ev er, asbest os exposure does not ac c ount f or 20% of mesot helioma c ases. Ot her f ac t ors assoc iat ed w it h t he dev elopment of mesot helioma inc lude radiat ion t herapy , c hronic inf lammat ion (inc luding t uberc ulosis and c hronic empy ema), genet ic predisposit ion, ot her nonasbest os mineral f ibers (erionit e, zeolit e), organic c hemic als P.604 (suc h as poly uret hane, et hy lene oxide, and poly silic one), and simian v irus 40 (53,207,322). Alt hough smoking is sy nergist ic ally assoc iat ed w it h asbest os in relat ion t o lung c anc er risk, it is not assoc iat ed w it h t he dev elopment of mesot helioma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1311

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 61 Pleural met ast ases separat ely v isible f rom pleural ef f usion. A: Chest radiograph in a 35- y ear- old w oman w it h breast c anc er and inc reasing dy spnea rev eals c omplet e opac if ic at ion of t he right hemit horax and lef t w ard mediast inal shif t . B: CT sc an rev eals t hat opac if ic at ion is a result of a large pleural ef f usion w it h enhanc ing pleural sof t t issue masses. Also not e enhanc ing met ast at ic nodules and pleural t hic kening w it hout ef f usion on t he lef t , not v isible on t he c hest radiograph. C : In anot her pat ient w it h met ast at ic breast c anc er and pleural ef f usion, CT rev eals underly ing enhanc ing, slight ly nodular t hic kening of t he pariet al pleura (ar r ow s). T he enhanc ement along t he v isc eral pleural surf ac e (ar r ow heads) may represent at elec t at ic lung or met ast ases.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1312

8 - Pleura, Chest Wall, and Diaphragm Almost all pat ient s w it h mesot helioma w ill dev elop an ipsilat eral pleural ef f usion (80,256,322,517). T he ef f usion is usually unilat eral, exudat iv e, and

of t en serosanguineous. It is v ariable in size, but may be large and obsc ure t he pleural neoplasm (F ig. 8- 69) (167,200,327). T he f luid t y pic ally has a low er at t enuat ion v alue t han adjac ent t umor. T here is of t en ev idenc e of asbest os exposure, inc luding pleural t hic kening and pleural plaques, in about half of pat ient s (F ig. 8- 70) (327,355,422), but c onc omit ant int erst it ial lung disease (asbest osis) is relat iv ely unc ommon (235). Calc if ic at ion of t he t umor is ext remely rare, t hough c alc if ied pleural plaques may bec ome inc orporat ed int o t he t umor (511). Malignant pleural mesot helioma is slight ly more c ommon on t he right side t han t he lef t , presumably bec ause of t he larger size of t he right pleural spac e (200). Bot h CT and MRI are able t o demonst rat e t he presenc e and ext ent of t he pleural mass and pleural ef f usion (10,167,295,327,514). T he t umor may present as dif f use nodular pleural t hic kening (F ig. 8- 71) or f oc al masses (F ig. 8- 72) bet w een t he lung and c hest w all (322,327). CT generally demonst rat es t hat t he neoplasm is more ext ensiv e t han apprec iat ed on c onv ent ional radiographs (10,167). T he disease is of t en adv anc ed at t he t ime of diagnosis, w it h c irc umf erent ial inv olv ement of t he lung produc ing ipsilat eral v olume loss and f ixat ion of t he mediast inum (F ig. 8- 73) (235,256,322,327,355,394,511). Bot h t he v isc eral and pariet al pleura are inv olv ed, and ext ension int o t he f issures and P.605 along t he mediast inal pleural surf ac e is c ommon (355,422). As t he t umor progresses, it may inv ade t he lung, peric ardium, heart , esophagus, mediast inum, ipsilat eral c hest w all, and oc c asionally t he c ont ralat eral c hest (60,248,464,473,511). It may penet rat e t he diaphragm and inv olv e t he perit oneal c av it y or ret roperit oneum (235,511). Loss of normal f at planes, ext ension int o mediast inal f at , and enc asement of more t han half t he c irc umf erenc e of a st ruc t ure, suc h as t he great v essels, heart , t rac hea, or esophagus, are f eat ures t hat suggest inv asion w it h eit her CT or MRI (511). Mediast inal ly mph node and dist ant met ast ases are possible (406,533). How ev er, t he ac c urac y of CT f or ident if y ing ly mph node met ast ases is limit ed, bec ause size is t he sole c rit eria f or ev aluat ion but is not highly spec if ic . CT may underest imat e t he ext ent of disease in early c hest w all inv olv ement (376,416). Deat h is usually a result of progression of loc al disease.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1313

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 62 Pleural met ast ases w it hout pleural ef f usion. A, B: CT sc ans show w idespread lef t - sided nodular pleural t hic kening result ing f rom met ast at ic melanoma, inc luding inv olv ement of t he mediast inal pleura. Inf eriorly , t he t umor enc ases t he lung and ext ends int o t he major f issure. Not e mult iple subc ut aneous met ast ases.

Alt hough CT may be v aluable in suggest ing t he diagnosis of mesot helioma in a pat ient w it h an unexplained persist ent pleural ef f usion on plain c hest radiography , it may oc c asionally be dif f ic ult t o c onf ident ly dif f erent iat e a malignant mesot helioma f rom adv anc ed benign pleural t hic kening or rounded at elec t asis (394). Benign asbest os- relat ed pleural plaques oc c asionally c an be large, irregular, and resemble mesot helioma (167). Benign pleural plaques also may enlarge on serial examinat ions, f urt her c onf ounding t he dist inc t ion f rom malignanc y . How ev er, inv olv ement of t he mediast inal pleura is rare in benign pleural disease and raises t he suspic ion of mesot helioma. Pleural t hic kening great er t han 1 c m, w hic h is nodular and c irc umf erent ial, is highly suggest iv e of a dif f use malignant proc ess but is not spec if ic f or mesot helioma (517). T his f inding, plus an ac c ompany ing P.606 pleural ef f usion, also c an be seen w it h met ast at ic c arc inoma, inv asiv e t hy moma, and ly mphoma (167,517).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1314

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 63 Pleural met ast ases det ec t ed as isolat ed small nodules. A: CT image show s an ant erior mediast inal mass (ar r ow s) result ing f rom an inv asiv e t hy moma, c ont aining a small c alc if ic at ion. B: T w o small peripheral nodules hav ing obt use margins (ar r ow s) represent pleural drop met ast ases.

F igure 8- 64 Pleural met ast asis f rom renal c ell c arc inoma. A, B: CT sc ans in a pat ient w it h w idespread met ast at ic renal c ell c arc inoma show a small right pleural ef f usion and a small, lent ic ular peripheral nodule (ar r ow head in A), c onf irming pleural met ast asis. Met ast ases t o t he right parat rac heal ly mph nodes (ar r ow s in A), t he lef t low er lobe (ar r ow in B), and t he c hest w all (ar r ow head in B) are also present .

It is of t en impossible t o dif f erent iat e malignant mesot helioma f rom met ast at ic adenoc arc inoma by CT or MRI. Dist inguishing reac t iv e mesot helial c ells f rom mesot helioma, and mesot helioma f rom c arc inoma, by f ine- needle aspirat ion c y t ology also may be dif f ic ult (295,327). Imaging- guided perc ut aneous c ut t ing needle biopsy has relat iv ely high sensit iv it y (70% t o 86%) and spec if ic it y (up

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1315

8 - Pleura, Chest Wall, and Diaphragm t o 100%) (3,317,439). Open pleural biopsy , hist oc hemist ry and

immunohist oc hemic al t ec hniques, or elec t ron mic rosc opy may be required f or a def init iv e diagnosis (207,295). T umor grow t h along needle biopsy t rac t s in mesot helioma is a c ommon c omplic at ion, est imat ed t o oc c ur in about 20% of c ases, but rarely in met ast at ic disease t o t he pleura (56). Mesot helioma may also grow along c hest t ube t rac t s or surgic al sc ars t o produc e c hest w all masses (322). Radiat ion t herapy may be used t o prev ent grow t h along c hest w all t rac t s. F or mesot helioma, CT is rec ommended as t he f irst t omographic imaging st udy . Mult iplanar MRI may add v alue in assessing c hest w all, diaphragm, and mediast inal inv olv ement in v ery selec t ed pat ient s w it h mesot helioma being c onsidered f or resec t ion (295,376). Mult idet ec t or CT w it h mult iplanar ref ormat t ing may f urt her improv e t he CT depic t ion of t umor ext ent in t hese regions, t hough it has not been ext ensiv ely st udied (406,511). Malignant mesot helioma has a low t o int ermediat e signal int ensit y on T 1- w eight ed MR images and high signal int ensit y on T 2- w eight ed images, and enhanc es w it h c ont rast (295,514). Loc ulat ed pleural f luid present s as areas of high signal int ensit y w it h T 2 w eight ing. F or st aging, t he use of dif f erent pulse sequenc es and gadolinium administ rat ion c an aid in dist inguishing t umor f rom normal t issue (511). An int ernat ional st aging sy st em based on t umor ext ent , nodal met ast asis, and dist ant m et ast ases (T NM) f eat ures (375,417) prov ides a f ramew ork f or c onduc t ing and ev aluat ing P.607 t he result s of c linic al t reat ment t rials using surgery , radiat ion, or c hemot herapy . T he T desc ript or depends on t he ext ent rat her t han t he size of t he t umor. T 1 t hrough T 3 t umors are pot ent ially resec t able, t hough may be loc ally adv anc ed, w hile T 4 t umors are t ec hnic ally unresec t able bec ause of dif f use c hest w all, perit oneal, c ont ralat eral pleural, mediast inal organ, spine, or int ernal peric ardial surf ac e inv olv ement . T he N and M desc ript ors are t he same as t hose used in t he Int ernat ional Lung Canc er St aging Sy st em (338) (see Chapt er 7). As w it h lung c anc er st aging, disc repanc ies exist bet w een imaging and surgic al st aging of mesot helioma, part ic ularly in t he ev aluat ion of c hest w all, diaphragmat ic , mediast inal, and nodal inv olv ement . How ev er, t he T NM st aging sy st em is pot ent ially applic able t o CT or MRI, w hic h c ould be used t o st rat if y pat ient s in t rials t hat do not inc lude surgic al int erv ent ion (375,417). T he diagnost ic ac c urac y of t hese t w o imaging modalit ies is similar,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1316

8 - Pleura, Chest Wall, and Diaphragm t hough MRI appears t o be bet t er t han CT in depic t ing inv asion of t he endot horac ic f asc ia and diaphragm and solit ary resec t able f oc i of c hest w all inv asion (190).

F igure 8- 65 Inv asiv e t hy moma. A, B: Lobular pleural sof t t issue t hic kening ext ends f rom t he ant erior mediast inal mass t o part ially enc ase t he lung.

F igure 8- 66 Met ast at ic adenoc arc inoma. A, B: Conf luent pleural t hic kening and nodular pleural masses almost c omplet ely enc ase t he lef t lung. A small lef t pleural ef f usion is present peripheral t o t he pleural mass in (B), indic at ing v isc eral pleural inv olv ement by t he t umor.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1317

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 67 Non- Hodgkin ly mphoma w it h pleural inv olv ement . CT sc an show s smoot h sof t t issue t hic kening of t he pleura post eriorly on t he lef t (ar r ow s).

Malignant mesot helioma has a v ery poor prognosis. It is v irt ually alw ay s f at al, w it h median surv iv al t imes f ollow ing diagnosis generally less t han 1 y ear, and w it h less t han 10% of pat ient s surv iv ing bey ond 3 y ears f ollow ing t he onset of sy mpt oms (53,80,200,327,383,417). Surgic al resec t ion, eit her by a pleurec t omy or ext rapleural pneumonec t omy , radiat ion t herapy , and c hemot herapy all are used f or t reat ment of malignant mesot helioma, but w it h lit t le impac t P.608 on surv iv al (5,80,256,418), and operat iv e morbidit y is high. T he rare pat ient w it h a pot ent ially resec t able t umor t y pic ally has normal ext rapleural f at and musc le w it h preserv at ion of int erc ost al spac es and normal signal c harac t erist ic s in t he c hest w all on MR images (376). Imaging c rit eria f or unresec t abilit y inc lude t umor enc asement of t he diaphragm; inv asion of ext rapleural sof t t issue or f at ; inv asion, displac ement , or separat ion of ribs by t umor; and inv asion or enc asement of essent ial mediast inal st ruc t ures (53,376). How ev er, f alse- negat iv e and f alse- posit iv e f indings may oc c ur, and mild pleural spreading of mesot helioma may be impossible t o det ec t by CT or MRI (322,376). Numerous c hemot herapeut ic agent s hav e been t est ed, most ly in v ery small t rials, w it h response rat es generally low er t han 15% (5). Radiat ion t herapy is used most of t en as palliat iv e t herapy f or loc alized pain. Bot h CT and MRI may be used t o det ec t rec urrenc e f ollow ing surgic al management and monit or response t o c hemot herapy .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1318

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 68 Ly mphoma w it h ext ensiv e pleural inv olv ement . CT sc an in a 10y ear- old male show s marked c irc umf erent ial sof t t issue t hic kening of t he pariet al pleura w it h a pleural ef f usion and assoc iat ed c ollapse of t he right low er lobe.

F igure 8- 69 Mesot helioma present ing w it h large pleural ef f usion. A, B: Unenhanc ed CT images in a 56- y ear- old w oman w it h a new onset of exert ional dy spnea show a large right pleural ef f usion, w it h only minimal pleural t hic kening seen post eriorly (ar r ow s). T here is c omplet e c ollapse of t he right lung (ar r ow heads) and lef t w ard mediast inal shif t . Not e c onnec t ion of c ollapsed right low er lobe t o mediast inal pleura v ia t he inf erior pulmonary ligament .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1319

8 - Pleura, Chest Wall, and Diaphragm Other Primary Pleural Neoplasms Ot her primary pleural malignanc ies are ext remely rare. T he pleura has been report ed as an at y pic al sit e of origin f or Cast leman disease (250), post t ransplant ly mphoprolif erat iv e disorder (266), angiosarc oma (386), liposarc oma (342,361), P.609 sy nov ial sarc oma (87,356), and epit helioid hemangioendot helioma, t he lat t er hav ing an aggressiv e c linic al c ourse w it h w idespread met ast asis w hen arising in t he pleura (94). Sof t t issue sarc omas dev eloping af t er radiat ion t herapy or c hemot herapy also may arise f rom t he pleura (F ig. 8- 74) (421). Wit h t he possible exc ept ion of f at in a w ell- dif f erent iat ed liposarc oma, t here are no spec if ic CT f indings t hat allow dist inc t ion f rom ot her primary or sec ondary pleural malignanc ies.

F igure 8- 70 Mesot helioma and pleural plaques. A, B: CT images show irregular and nodular pleural t hic kening (ar r ow heads) and loc ulat ed f luid in t he lef t hemit horax due t o mesot helioma. T he mult iple c alc if ied pleural plaques present bilat erally (ar r ow s) indic at e prev ious asbest os exposure.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1320

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 71 Mesot helioma. A, B: CT images show w idespread, nodular, enhanc ing right pleural t hic kening.

PLEURODESIS Sc lerosis and f usion of t he pleural surf ac es, or pleurodesis, c an be ef f ec t iv e t herapy f or a malignant pleural ef f usion, unresolv ing or rec urrent pneumot horax, c hy lot horax, and idiopat hic or ot her rec urrent pleural ef f usion. Pleurodesis may be ac c omplished by inst illat ion of sc lerosing agent s or by mec hanic al pleural abrasion. Chemic al sc lerosing agent s suc h as doxy c y c line or bleomy c in hav e long been used, but t alc appears t o be more ef f ec t iv e (98,237,424). Wit h t he inc reased popularit y of t alc , possible c omplic at ions of empy ema, reexpansion edema, and ac ut e respirat ory dist ress sy ndrome hav e been rec ognized, w hic h may be dose dependent (98,237,290,424). Sy st emic absorpt ion of int rapleural t alc has been ident if ied, w hic h may be a c ausat iv e f ac t or in t he dev elopment of ac ut e respirat ory dist ress sy ndrome (98,290). Af t er pleurodesis, a v ariable degree and dist ribut ion of pleural t hic kening and nodularit y are usually seen on CT . F luid loc ulat ions of v ariable size are c ommon. T he high densit y of t alc inst illed int o t he pleural spac e resembles pleural c alc if ic at ion; t he appearanc e is c lust ered and nodular w it h t alc slurry and seen as f ine linear deposit s w it h t alc poudrage (see F ig. 8- 32) (346).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1321

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 72 Mesot helioma. A, B: CT images show mult iple, smoot hly c irc umsc ribed, pleural sof t t issue masses (ar r ow s), a pleural ef f usion, and a c ollapsed lef t low er lobe (ar r ow heads).

F igure 8- 73 Mesot helioma. A, B: CT show s c irc umf erent ial, mildly enhanc ing, nodular pleural t hic kening enc asing t he right lung. Not e inv olv ement of mediast inal pleura, ext ension int o t he major f issure (M) and azy goesophageal rec ess (R), and diminished v olume of t he right lung. Right parat rac heal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1322

8 - Pleura, Chest Wall, and Diaphragm

ly mphadenopat hy also is seen (ar r ow ). C : In anot her pat ient , CT show s similar f indings w it h c irc umf erent ial enc asement of t he lef t lung, ext ension of t he t umor int o t he major f issure, and v olume loss.

F igure 8- 74 Spindle c ell sarc oma of t he pleura. A, B: CT images in a 38- y earold w oman w ho had c hemot herapy and radiat ion t herapy in her lat e t eens f or Hodgkin disease show c irc umf erent ial, mildly enhanc ing pleural t hic kening and bilat eral pleural ef f usions.

P.610 P.611

POSTPNEUMONECTOMY SPACE T he spac e c reat ed f ollow ing pneumonec t omy , bordered by t he residual subc ost al, diaphragmat ic , and mediast inal pariet al pleura, init ially c ont ains serosanguineous f luid, af t er absorpt ion of t he gas in t he immediat e post operat iv e period. Some of t his f luid is ev ent ually resorbed, and t he post pneumonec t omy spac e is gradually reduc ed in size (363). How ev er, in only about 20% of pat ient s does it bec ome c omplet ely oblit erat ed and oc c upied by reloc at ed mediast inal st ruc t ures. In t he remainder, a f luid- f illed spac e persist s f or many y ears f ollow ing surgery . A range of anat omic al alt erat ions may oc c ur c onsequent t o rot at ion and displac ement of t he mediast inal st ruc t ures, as w ell as hy perexpansion of t he c ont ralat eral lung. Know ledge of t hese v arious appearanc es on CT is essent ial so as not t o c onf use dist ort ed normal anat omy w it h a pat hologic c ondit ion (47). T he post pneumonec t omy spac e is relat iv ely homogeneous and of low er at t enuat ion t han sof t t issue bec ause of t he c ont ained residual f luid. F ollow ing a right pneumonec t omy (F ig. 8- 75), t he mediast inum t ends t o rot at e, w it h a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1323

8 - Pleura, Chest Wall, and Diaphragm

result ant t ransv erse orient at ion of t he aort ic arc h, and t he c ont ralat eral lung herniat es ant eriorly . In general, t he smaller t he post pneumonec t omy spac e is, t he great er t he lung herniat ion. T he mediast inal shif t may be so ext reme f ollow ing a right pneumonec t omy in c hildren or t hin adult s t hat t he dist al t rac hea and remaining lef t main st em bronc hus are part ially c ompressed bet w een t he aort a and lef t pulmonary art ery , result ing in dy spnea or rec urrent lef t lung inf ec t ions (post pneumonec t omy sy ndrome) (F ig. 8- 76) (452). T hough most c ases oc c ur f ollow ing right pneumonec t omy or af t er lef t pneumonec t omy in pat ient s w it h a right aort ic arc h (170), t hey c an also oc c ur af t er lef t pneumonec t omy in pat ient s w it h a lef t arc h (106). Ef f ec t iv e management is obt ained by plac ement of a spac e- oc c upy ing prost hesis, suc h as a breast prost hesis or t issue expander, int o t he pneumonec t omy spac e t o ret urn t he mediast inum t o it s normal posit ion; bec ause bronc homalac ia may be assoc iat ed w it h t he sy ndrome, insert ion of a bronc hial st ent may be required (106). F ollow ing a lef t pneumonec t omy , t he mediast inum shif t s so t hat t he usual ant eropost erior orient at ion of t he aort ic arc h generally is maint ained; t he c ont ralat eral lung may herniat e post eriorly as w ell as ant eriorly (F ig. 8- 77). As a result of a prev ious pneumonec t omy , opac if ic at ion of t he hemit horax makes ev aluat ion of t he post pneumonec t omy spac e and ipsilat eral mediast inum ext remely dif f ic ult w it h c onv ent ional radiography . Disease in t his area c an be det ec t ed only w hen it is so gross t hat , f or example, mediast inal shif t oc c urs or an air–f luid lev el dev elops in t he pneumonec t omy spac e. CT and MRI are more sensit iv e f or det ec t ing rec urrent neoplasm or anot her c omplic at ion at an earlier st age (83,156,379). Rec urrenc e of bronc hogenic c arc inoma most c ommonly oc c urs near t he bronc hial st ump or in t he mediast inal ly mph nodes. Somet imes, pleural met ast ases c an be ident if ied as sof t t issue densit y nodules projec t ing int o t he low er at t enuat ion post pneumonec t omy spac e (F igs. 8- 78 and 8- 79). Palliat iv e radiat ion t herapy may be t arget ed t o t he rec urrent t umor. CT also may be of v alue in diagnosing inf ec t ion in t he post pneumonec t omy spac e, w hic h may oc c ur soon or y ears P.612 af t er surgery (83,188). St raight ening or c onv ex expansion of t he c onc av e mediast inal border may oc c ur w it h a c omplic at ing empy ema, w it h or w it hout shif t ing of t he mediast inum t ow ard t he c ont ralat eral side; ot her CT f eat ures inc lude air in t he post pneumonec t omy spac e, an inc rease in t he baseline

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1324

8 - Pleura, Chest Wall, and Diaphragm post operat iv e t hic kening, enhanc ement of t he residual pariet al pleura, and empy ema nec essit at is (83).

F igure 8- 75 Normal anat omy af t er right pneumonec t omy . A, B: CT sc ans at t he lev el of t he aort ic arc h (ARCH) and right pulmonary art ery (RPA), respec t iv ely , demonst rat e f luid f illing of t he post pneumonec t omy spac e (PPS). T he spac e, demarc at ed ext ernally by t he residual pariet al pleura (ar r ow heads), is c ont ained w it hin a c ont rac t ed right hemit horax. Slight mot ion in t he met allic surgic al c lips (ar r ow ) c an produc e minor st reak art if ac t s. S, superior v ena c av a; T , t rac hea; e, esophagus; AA, asc ending aort a; DA, desc ending aort a; PA, main pulmonary art ery ; L, lef t main st em bronc hus; li, lef t upper lobe and lingular bronc hus; v , lef t superior pulmonary v ein; lp, lef t low er lobe pulmonary art ery .

F igure 8- 76 Post pneumonec t omy sy ndrome. A, B: CT images in a 54- y ear- old w oman w it h inc reasing dy spnea and a hist ory of right pneumonec t omy demonst rat e marked herniat ion of t he mediast inum and hy perexpanded lef t

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1325

8 - Pleura, Chest Wall, and Diaphragm lung int o t he right pneumonec t omy spac e, w it h c ompression of t he lef t main bronc hus (ar r ow s), arising f rom t he c arina in (A), bet w een t he lef t pulmonary art ery (P) and t he desc ending aort a (A). Esophagus (ar r ow heads) is

dist ended w it h air. T he pat ient w as t reat ed w it h insert ion of spac e- oc c upy ing saline breast prost heses int o t he right pleural spac e t o shif t t he mediast inum t o t he midline and insert ion of a t rac heobronc hial st ent bec ause of bronc homalac ia.

CHEST WALL CT is a v aluable t ec hnique f or det ermining t he presenc e and ext ent of v arious t y pes of c hest w all pat hology (223,225,257). T he sof t t issues of t he c hest w all and t he ribs, spine, and shoulder girdle should be inspec t ed w henev er a CT examinat ion of t he c hest is perf ormed; f indings P.613 in t he c hest w all may hav e been unsuspec t ed c linic ally . Phy sic al examinat ion and plain f ilm radiography are of limit ed v alue in t he det ec t ion and c harac t erizat ion of lesions inv olv ing t he c hest w all, espec ially in obese pat ient s. T he abilit y of CT t o dist inguish bet w een f at , sof t t issue, and bone densit ies and display t he indiv idual c omponent s of t he c hest w all in c ross sec t ion c an prov ide import ant c linic al inf ormat ion (166). In some pat ient s, CT and MRI hav e c omplement ary roles in assessing c hest w all pat hology (249,267,483,484,524,526). CT has bet t er spat ial resolut ion and depic t s c ort ic al bone dest ruc t ion bet t er, w hereas direc t mult iplanar imaging, bet t er sof t t issue c harac t erizat ion, and f low - sensit iv e pulse sequenc es are adv ant ages of MRI.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1326

8 - Pleura, Chest Wall, and Diaphragm F igure 8- 77 Normal anat omy af t er lef t pneumonec t omy . A, B: CT sc ans at

t he lev el of t he main pulmonary art ery (PA) show ing a residual, relat iv ely low densit y , post pneumonec t omy spac e (PPS). Not e t hat t he medial border of t he spac e is eit her c onc av e or st raight in it s int erf ac e w it h t he mediast inum. Mot ion in a lef t bronc hial st ump c lip c reat es some st reak art if ac t s. T he right lung has herniat ed (ar r ow s) ant erior t o t he asc ending aort a (AA), as w ell as post erior t o t he bronc hus int ermedius int o t he azy goesophageal rec ess (aer). DA, desc ending aort a; ar r ow head, esophagus.

F igure 8- 78 Rec urrent c anc er. Rec urrent c arc inoma (Ca) is seen inf ilt rat ing adjac ent f at and inv ading t he c hest w all at t he t horac ot omy sit e, ant erolat eral t o t he post pneumonec t omy spac e (PPS). Not e t he regenerat ing periost eal new bone f ormat ion f rom t he t horac ot omy (ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1327

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 79 Rec urrent bronc hogenic c arc inoma. CT image show s nodular mass (m) w it hin t he right post pneumonec t omy spac e (PPS).

F igure 8- 80 Pec t us exc av at um. Marked def ormit y w it h inw ard displac ement of t he st ernum is seen assoc iat ed w it h displac ement of t he heart int o t he lef t hemit horax and ant erior c onc av it y of t he ant erior c hest w all.

In some c ases, CT may be helpf ul in ident if y ing c ongenit al t horac ic c age def ormit ies, suc h as pec t us exc av at um (F ig. 8- 80) or t he absenc e of a pec t oral musc le (F ig. 8- 81) (104,225). CT may be usef ul in c harac t erizing benign post t raumat ic or dev elopment al lesions in pat ient s w it h suspic ious plain f ilm f indings. CT may det ec t subt le lesions in t he ribs (F ig. 8- 82), spine, or st ernum (F ig. 8- 83) not demonst rat ed on c onv ent ional c hest or rib det ail

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1328

8 - Pleura, Chest Wall, and Diaphragm radiographic examinat ions; spinal c anal enc roac hment may be demonst rat ed (F ig. 8- 84). Direc t ext ension of lung, pleural, or mediast inal malignanc y or inf ec t ion not det ec t able on radiographs may be depic t ed.

Sternum and Clavicles CT is w ell suit ed t o ident if y ing disease in and around t he st ernum (135,185,516). T he manubrium is t y pic ally oblique t o t he t ransv erse plane of sec t ion and t he ant erior and post erior c ort ic al margins may appear indist inc t (see F ig. 5- 41), P.614 a c ommon v ariat ion t hat should not be mist aken f or pat hology (164,185,471,516). Irregular c alc if ic at ion at t he st ernomanubrial junc t ion and at t he t ransit ion f rom body t o xiphoid also is c ommon and should not be mist aken f or a sc lerot ic lesion (164,185). T he c ort ic al surf ac e of t he st ernoc lav ic ular joint is t y pic ally smoot h and sy mmet ric , but degenerat iv e c hanges may produc e spur f ormat ion or a v ac uum phenomenon w it hin t he joint (164,471). Ot her st ernoc lav ic ular irregularit ies oc c asionally enc ount ered inc lude subc hondral erosion, unev enness of art ic ular surf ac es, and subc hondral c y st s and sc lerosis (297). Irregular sc lerosis and c ort ic al unsharpness are c ommonly enc ount ered at t he st ernoc ost al junc t ions and should not be mist aken f or pat hology (185,516). T he st ernalis musc le, a relat iv ely unc ommon normal v ariant of unknow n purpose, c an be depic t ed by CT or MRI. Ext ending f rom t he inf rac lav ic ular lev el t o t he inf erior st ernum, it has a f lat , narrow c ont our ov erly ing t he medial pec t oralis major musc le in t he supine posit ion and is more f requent ly unilat eral t han bilat eral (58). Assoc iat ion of a markedly enlarged st ernalis w it h a part ially def ec t iv e pec t oralis musc le has been report ed (261).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1329

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 81 Poland sy ndrome. Congenit al absenc e of t he right pec t oralis major and minor musc les in a 69- y ear- old man.

F igure 8- 82 Rib dest ruc t ion f rom mult iple my eloma. Bone w indow set t ing show s a dest ruc t iv e rib lesion w it h an ext raosseous sof t t issue c omponent (ar r ow ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1330

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 83 St ernal dest ruc t ion f rom mult iple my eloma. An expansile, ly t ic lesion is present w it h areas of c ort ic al dest ruc t ion.

St ernoc ost oc lav ic ular hy perost osis, w hic h may be ac c ompanied by longst anding pain and sw elling in t he ant erior c hest , is c harac t erized by hy perost osis and sof t t issue ossif ic at ion bet w een t he c lav ic le, st ernum, and upper ribs (157,404). T he bone ov ergrow t h may lead t o a t hic k, w ide st ernum and t he appearanc e should not be c onf used w it h Paget disease or c hronic ost eomy elit is. T he c ommon c auses of painf ul sc lerosis and sw elling of t he medial end of t he c lav ic le, namely , ost eoart hrit is, st ernoc lav ic ular sept ic art hrit is (F ig. 8- 85), and c ondensing ost eit is, are usually dist inguishable by CT or MRI (182). T he st ernoc lav ic ular P.615 joint is a c ommon sit e f or sept ic art hrit is (262). An unusual sy ndrome inv olv ing sy nov it is, ac ne, palmoplant ar pust ulosis, hy perost osis, and ost eit is (SAPHO) most f requent ly af f ec t s t he st ernoc lav ic ular region, and may simulat e inf ec t ion or neoplasm (135). Alt hough rare, w hen enc ount ered, ost eomy elit is of t he st ernum is usually a c omplic at ion of surgic al median st ernot omy . An inc reased inc idenc e of st ernal and st ernoc lav ic ular joint inf ec t ion also has been assoc iat ed w it h int rav enous drug abuse (135,225). Radiat ion t herapy may result in loc alized ost eoporosis, sc lerosis, or ev en asept ic nec rosis (262).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1331

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 84 Plasmac y t oma. Dest ruc t iv e sof t t issue mass inv olv ing t he post erior element s of t he spine and a low er t horac ic rib ext ends int o t he spinal c anal.

F igure 8- 85 St ernoc lav ic ular joint and c hest w all absc ess. A: CT image in a 74- y ear- old man w it h diabet es and St aphy loc oc c us aur eus bac t eremia rev eals a f luid c ollec t ion c ent ered in t he right st ernoc lav ic ular joint (ar r ow ), w it h ext ension t o t he right pec t oralis musc les (ar r ow heads). B: Slight ly more c audal, t he f luid c ollec t ion ext ends f rom t he c hest w all t o t he ant erior ext rapleural spac e (ar r ow heads in B) and int o t he ant erior mediast inum (ar r ow in B).

St ernal f rac t ures (F ig. 8- 86) are usually a result of st eering w heel and seat belt injuries (135,206). CT may miss st ernal f rac t ures orient ed in t he sc an plane (206); t hinner sec t ions and sagit t al rec onst ruc t ions, readily obt ainable w it h mult idet ec t or sc anning, should reduc e f alse negat iv es. Ant erior

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1332

8 - Pleura, Chest Wall, and Diaphragm mediast inal hemat oma c an result f rom mediast inal injuries unrelat ed t o t he st ernum and is not spec if ic f or st ernal f rac t ure. When st ernal f rac t ures are

ident if ied, t he possibilit y of c ardiac and mediast inal v asc ular injuries should be c onsidered.

F igure 8- 86 St ernal f rac t ure. CT image of a 69- y ear- old unrest rained driv er w ho c rashed int o a t ree rev eals buc kling and disc ont inuit y of t he post erior c ort ex of t he st ernum, w it h an adjac ent small ant erior mediast inal hemat oma.

Primary t umors and met ast ases t o bone are w ell delineat ed by CT . Ly mphoma, bronc hogenic c arc inoma, and breast c arc inomas may inv ade t he st ernum direc t ly . Mult iple my eloma and hemat ogenous met ast ases f rom lung, breast , prost at e, t hy roid, or renal c arc inomas are t he most c ommon neoplasms inv olv ing t he st ernum. T hey present as dest ruc t iv e lesions, of t en w it h an assoc iat ed sof t t issue mass. Primary malignant t umors, suc h as c hondrosarc oma, plasmac y t oma, ly mphoma, ost eogenic sarc oma, or Ew ing sarc oma, are muc h less c ommon (516). Benign t umors report ed t o inv olv e t he c lav ic le and st ernum inc lude enost osis (bone islands), simple bone c y st , giant c ell t umor, aneury smal bone c y st , f ibrous dy splasia, hemangioma, eosinophilic granuloma, neurof ibroma, c hondromy xoid f ibroma, and dermoid c y st (135,262). St ernal and st ernoc lav ic ular abnormalit ies are also w ell depic t ed by MRI (23). MRI may be part ic ularly usef ul f or det ermining t he marrow and sof t t issue

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1333

8 - Pleura, Chest Wall, and Diaphragm ext ent of inf ec t ion or neoplasm, and assessing operabilit y (135,445), t hough art if ac t s may limit t he ev aluat ion if st ernot omy w ires are present (23,225). How ev er, MRI is limit ed in show ing c alc if ic at ion suc h as t he c art ilaginous mat rix of c hondrosarc oma (23,135). T hus, CT and MRI c an hav e c omplement ary roles.

Episternal Ossicles Epist ernal ossic les represent a normal v ariant , det ec t ed in about 1.5% of c hest CT examinat ions. T hey may be paired or single, and are post erior and c ephalad t o t he c ranial border of t he manubrium (F ig. 8- 87) (472). T hey range f rom 2 t o 15 mm in diamet er, av eraging 10 mm, may be sy mmet ric or P.616 asy mmet ric in size, and one or bot h may be f used w it h t he manubrium (472). T hey should not be c onf used w it h a f rac t ure f ragment , sequest ra, f oreign bodies, c alc if ied ly mph nodes, or v asc ular c alc if ic at ion (472,516).

F igure 8- 87 Epist ernal bones. Image at t he lev el of t he st ernoc lav ic ular joint show s t he t y pic al loc at ion of epist ernal ossic les (ar r ow s) post erior t o t he manubrium.

Pectus Deformities Pec t us exc av at um is c harac t erized as an inw ard depression of t he middle and low er st ernum, w hic h may reduc e t he prev ert ebral spac e and c ause lef t w ard displac ement and rot at ion of t he heart and mediast inal st ruc t ures (see F ig. 880) (175,225). T he st ernum is of t en rot at ed or t ilt ed as w ell. Pec t us c arinat um is c harac t erized by t he c onv ex prot rusion of t he st ernum, and is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1334

8 - Pleura, Chest Wall, and Diaphragm less c ommon t han pec t us exc av at um (225). T he st ernum is of t en w ider and longer t han normal (225,516). Bot h of t hese abnormalit ies are w ell

c harac t erized on lat eral c hest radiographs, but CT or MRI may be of benef it in selec t ed c ases in w hic h operat iv e c orrec t ion is c ont emplat ed.

Sternoclavicular Dislocation Ant erior st ernoc lav ic ular disloc at ion is more c ommon and easier t o diagnose c linic ally bec ause of t he usually obv ious ant erior c hest w all def ormit y . Post erior disloc at ion, t hough f ar less c ommon, is dif f ic ult t o diagnose bot h c linic ally and radiographic ally , and is a muc h more serious disorder. T he medial end of t he c lav ic le may injure adjac ent mediast inal v asc ular st ruc t ures suc h as t he brac hioc ephalic v eins, c an c ause c ompression or displac ement of t he t rac hea, and c an result in esophageal injury (120,328,389). Rarely , superior disloc at ion of t he c lav ic ular head may oc c ur. CT is t he pref erred imaging proc edure, allow ing rapid def init ion of t he relat ionship bet w een t he c lav ic ular head and st ernum, def init iv e diagnosis and dist inc t ion bet w een t he dif f erent t y pes of disloc at ion (F ig. 8- 88), as w ell as ident if ic at ion and ev aluat ion of any assoc iat ed v asc ular or sof t t issue injuries (108,120,285). Disloc at ions, abnormalit ies of adjac ent sof t t issues, and oc c ult v asc ular injury also c an be ev aluat ed w it h MRI (120).

F igure 8- 88 Post erior st ernoc lav ic ular disloc at ion. CT image at bone w indow set t ings show s t raumat ic displac ement of t he right c lav ic ular head (C), bet w een t he right brac hioc ephalic v ein (ar r ow head) and art ery (ar r ow ), post erior t o t he manubrium. Cont rast ent ers t he lef t brac hioc ephalic v ein (v ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1335

8 - Pleura, Chest Wall, and Diaphragm Ribs

T he oblique c ourse of t he ribs prec ludes assessing more t han a short segment in any giv en t ransv erse sec t ion (114,311). One simple t ec hnique f or det ermining t he spec if ic ribs inv olv ed in any det ec t ed pat hologic proc ess begins by ident if y ing t he f irst rib. T he ant erior port ion of t he f irst rib lies along t he ant erior c hest w all at approximat ely t he lev el of t he c lav ic le. Count ing post eriorly in t he same sec t ion, one c an usually ident if y t he sec ond and t hird ribs, and t hen, on sequent ial images, c orresponding ribs c an be ident if ied (F ig. 8- 89) (44). Similarly , t he sec ond c ost al c art ilage c an be ident if ied at t he lev el of t he st ernal angle, and usually t he t hird t hrough sixt h ribs c an be ident if ied in t he same sec t ion (263). Anot her met hod of ident if y ing ribs is t o not e t hat t he st ernal end of t he sev ent h c ost al c art ilage lies in t he same axial plane as t he proximal xiphoid (245). Supernumerary int rat horac ic ribs are rare c ongenit al anomalies w it h t he st ruc t ure of a t y pic al rib, but w it h an aberrant loc at ion and orient at ion. T hough adequat ely c harac t erized by c hest radiography in most c ases, CT is ev en more def init iv e f or dist inguishing int rat horac ic ribs f rom abnormalit ies suc h as pleural plaques, sc imit ar sy ndrome, or f oreign bodies (271,299). Alt hough seldom needed primarily f or t he ev aluat ion of rib f rac t ures, CT is more sensit iv e t han port able radiography in ident if y ing ac ut e f rac t ures in t he t rauma set t ing (258), and is also sensit iv e f or demonst rat ing assoc iat ed hemat oma, pneumot horax, lung c ont usion, sof t t issue gas, and pleural ef f usion. A f lail c hest , w it h paradoxic al respirat ory mov ement of t he f lail port ion, may oc c ur w it h f rac t ures of f iv e or more P.617 adjac ent ribs or w it h mult iple f rac t ures of t hree or more ribs (258). Rarely , sev ere blunt t rauma result s in herniat ion of t he lung int o t he c hest w all (22,268,328). Lung hernias, w hile rare, also may oc c ur af t er t horac ic surgery (165,518), spont aneously (f ollow ing c oughing or sneezing) (65,121,308,415,518), or c ongenit ally (121,518). T hey may present c linic ally as a f oc al bulging of t he c hest w all or nec k t hat appears or c hanges in size w it h breat hing, c oughing, st raining, or lif t ing (22). Apic al lung hernias may c ause t rac heal dev iat ion (308). T he diagnosis of lung hernia is readily made or c onf irmed by CT (F ig. 8- 90). Lung hernias are usually asy mpt omat ic , and surgic al repair is of t en unnec essary , but pain or hemopt y sis may indic at e st rangulat ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1336

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 89 Count ing ribs. T ransaxial sec t ion of t he upper t horax demonst rat ing landmarks usef ul in c ount ing t he t horac ic ribs. Ant eriorly , t he manubrium (M) and c lav ic ular heads (Cl) are readily ident if ied. T he f irst rib end (1) is seen just lat eral t o t his; next t o t his is t he sec ond rib (2), and post eriorly , t he t hird rib (3).

Oc c asionally , CT is usef ul f or dist inguishing bet w een an enlarged and sc lerot ic f irst c ost oc hondral c art ilage and a lung nodule w hen radiographs are indet erminat e (F igs. 8- 91 and 8- 92; see F ig. 5- 42). Callus f ormat ion around a rib f rac t ure (F ig. 8- 93), sc lerot ic c ost ov ert ebral art ic ulat ions (F ig. 8- 94), bone islands (see F ig. 7- 21), and ost eoc hondromas (F ig. 8- 95) are ot her benign rib lesions t hat c an mimic pulmonary pat hology on c onv ent ional c hest radiography . Healing f rac t ures simulat ing a nodule are a part ic ularly c ommon problem in immunosuppressed pat ient s f ollow ing c ardiac and lung t ransplant at ion, w hen a new nodule may herald a f ungal or ot her opport unist ic inf ec t ion or ly mphoprolif erat iv e disease, and almost alw ay s c an be depic t ed def init iv ely by CT . T iet ze sy ndrome, an inf lammat ory c ondit ion t hat inc ludes c hest pain as w ell as t enderness and sw elling of t he c ost al c art ilage, c an c linic ally mimic a c hest w all mass. T hough usually inv olv ing a solit ary c ost al c art ilage, it may be mult if oc al (364). T umor may be exc luded by CT , alt hough mild f oc al c art ilaginous enlargement is somet imes seen (516). Cost oc hondrit is result ing f rom bac t erial or f ungal inf ec t ions may c ause f ragment at ion and dest ruc t ion of c ost al c art ilage w it h sof t t issue sw elling, low at t enuat ion c art ilage, and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1337

8 - Pleura, Chest Wall, and Diaphragm loc alized peripheral c alc if ic at ion (318,364). Dif f use enlargement of c ost al c art ilages also oc c urs in ric ket s and ac romegaly (364).

A diagnost ic problem c an oc c ur in a pat ient w it h a hist ory of c arc inoma and an abnormal radionuc lide bone sc int igram w hen a c orresponding abnormalit y c annot be seen on P.618 st andard radiography . CT may be helpf ul in demonst rat ing c allus and rib def ormit y , c harac t erist ic of a healing f rac t ure, or may show bone dest ruc t ion and an assoc iat ed ext raosseous sof t t issue mass c harac t erist ic of met ast asis (311). Neoplasms inv olv ing t he ribs and c hest w all are rev iew ed lat er in t he sec t ion t it led T umors of t he Chest Wall.

F igure 8- 90 Lung hernia. A: CT image in a 64- y ear- old man w it h a hist ory of unspec if ied c hest t rauma in t he past and a bulging c hest w all mass on inspirat ion show s herniat ion of t he lef t low er lobe int o t he c hest w all t hrough a w ide int erc ost al def ec t . B: More c audal CT image show s assoc iat ed herniat ion of abdominal f at , c olon (ar r ow heads), and t he lat eral t ip of t he spleen. A small hiat al hernia (ar r ow ) is also seen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1338

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 91 Cost oc hondral c art ilage simulat ing a nodule. A: Chest radiograph show s a 1.4- c m opac it y projec t ing ov er t he lef t upper lobe (ar r ow ). B: CT demonst rat es prominent , densely c alc if ied c ost oc hondral c art ilage indent ing t he lung.

Collateral Vessels Enlarged c ollat eral v essels may be seen in t he c hest w all in pat ient s w it h superior v ena c av a obst ruc t ion (F ig. 8- 96) (84) or oc c lusion of anot her major v ein in t he t horax or abdomen. T hey appear on CT as round or t ubular st ruc t ures t hat enhanc e af t er int rav enous c ont rast administ rat ion. T ransient enhanc ement of normal t horac ic w all v eins on t he side of c ont rast injec t ion, part ic ularly in t he perisc apular and suprac lav ic ular regions, may be seen bec ause of ret rograde f low in c hest w all v eins result ing f rom c ompression of t he subc lav ian v eins during hy perabduc t ion of t he arms and t he inc reased f low rat es produc ed using a pow er injec t or.

CHEST WALL INFECTION Inf lammat ion, c ellulit is, f asc iit is, and absc esses of t he c hest w all may oc c ur as a result of surgery , t rauma, or direc t ext ension f rom pulmonary , pleural, or mediast inal inf ec t ions (333). T he ext ent and sev erit y of c hest w all inf ec t ions may be dif f ic ult t o assess by phy sic al examinat ion alone. Bac t eria suc h as St aphy loc oc c us, Pseudom onas, and Klebsiella and ot her organisms suc h as Ac t inom y c et es, Noc ar dia, Asper gillus, and My c obac t er ium may inv olv e t he c hest w all, leading t o rib dest ruc t ion and periost eal elev at ion, loss of sof t t issue planes, and a c hest w all mass (225,234,249,333,448). T he risk is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1339

8 - Pleura, Chest Wall, and Diaphragm inc reased w it h age, diabet es, surgery , t rauma, and in immunoc ompromised pat ient s (225,249,448). Int rav enous drug abusers are at inc reased risk of st ernoc lav ic ular and st ernoc hondral inf ec t ions (225). Many c hest w all

inf ec t ions are t he result of ext raosseous ext ension of ost eomy elit is (516), but c an also arise f rom inf ec t ion of t he lung or pleural spac e, usually t uberc ulous or f ungal; ac t inomy c osis is w ell know n f or a propensit y t o t rav erse t issue boundaries and ext end f rom t he lung or pleural spac e int o t he c hest w all (F ig. 8- 97) (225,264). T he plain radiographic f indings in c hest w all inf ec t ion c an be subt le and dif f ic ult t o det ec t bec ause of c omplex skelet al anat omy or assoc iat ed ost eopenia; pulmonary inf ilt rat es or pleural ef f usions may obsc ure osseous det ail. In post operat iv e pat ient s, nuc lear medic ine imaging of t en is not benef ic ial bec ause t he radionuc lide normally c onc ent rat es in surgic al sit es. CT and MRI t end t o prov ide c omplement ary inf ormat ion in ev aluat ing t he ext ent of c hest w all disease (257,448). T he t y pic al appearanc e is t hat of a sof t t issue mass or absc ess w it h inf ilt rat ion of f at planes, and t here may be assoc iat ed bone dest ruc t ion. Sof t t issue inf lammat ion is bet t er demonst rat ed w it h MRI, w hereas CT bet t er depic t s small areas of bone dest ruc t ion and periost eal reac t ion (516). Chest w all ost eomy elit is is w ell depic t ed by MRI as dec reased marrow signal int ensit y on T 1- w eight ed images, inc reased marrow signal on T 2- w eight ed images, and f oc al enhanc ement (249,337). Bone dest ruc t ion, sequest ra, and surrounding sof t t issue absc esses w it h rim enhanc ement are c ommon f indings in t uberc ulous c hest w all inf ec t ion, w hic h may af f ec t t he rib shaf t , c ost ov ert ebral joint , or c ost oc hondral junc t ion, and inf requent ly t he st ernum (4,132,238,275,335,360).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1340

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 92 T rue lef t apic al pulmonary nodule and prominent right f irst c ost oc hondral junc t ion. A: CT demonst rat es a prominent right f irst c ost oc hondral c art ilage (ar r ow head). B: More c audally , a nodular opac it y is seen just post erior t o t he lef t c ost oc hondral junc t ion (ar r ow ). C : Highresolut ion CT image show s a spic ulat ed lef t upper lobe pulmonary nodule (ar r ow ), subsequent ly c onf irmed t o represent a bronc hogenic c arc inoma.

P.619 Dif f use or f oc al inf ec t ions may be indist inguishable f rom a neoplast ic proc ess by imaging alone. How ev er, t he presenc e of f luid c ollec t ions or air–f luid lev els w it hin t he subc ut aneous t issues, skin f ist ulae, or an assoc iat ed empy ema should be a c lue t o t he inf ec t ious nat ure of a c hest w all proc ess. Bec ause many c hest w all inf ec t ions begin in t he lung or pleural spac e, an adjac ent pulmonary inf ilt rat e or empy ema may be observ ed. In ant erior c hest

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1341

8 - Pleura, Chest Wall, and Diaphragm

w all inf ec t ions (inc luding st ernoc lav ic ular), ant erior mediast inal ext ension c an oc c ur (see F ig. 8- 85); inc reased densit y and st randing in ant erior mediast inal f at , f luid c ollec t ions, and mass ef f ec t on t he great v essels may be seen on CT (360).

Empyema Necessitatis Empy ema nec essit at is oc c urs w hen inf ec t ed pleural f luid rupt ures int o t he c hest w all, of t en present ing as a subc ut aneous mass. T his oc c urs most c ommonly sec ondary t o t uberc ulosis (F ig. 8- 98) but also may oc c ur as a c onsequenc e of ac t inomy c osis (see F ig. 8- 97) or blast omy oc osis or may ev en f ollow t horac ent esis of a py ogenic empy ema (159,172,260,516). Wit h ac t inomy c osis, sw elling, draining sinus t rac t s and f ist ulas, periost eal reac t ion, and bone dest ruc t ion are c ommon (133,257). Indiv iduals w it h poor dent al hy giene and immunosuppression are predisposed. T he t reat ment of c hoic e is surgic al dГ©bridement . CT c an demonst rat e c ont iguit y or proximit y of t he subc ut aneous P.620 absc ess w it h a pleural spac e c ollec t ion, and may show areas of lung dest ruc t ion beneat h t he pleural disease t hat w ere obsc ured on c onv ent ional radiographs (45,159).

F igure 8- 93 Healing rib f rac t ure. A: F oc al right upper lobe opac it y (ar r ow ) seen on c hest radiograph f ollow ing c ardiac t ransplant at ion. B: T he CT examinat ion c onf irms t he c ause t o be c allus f ormat ion assoc iat ed w it h a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1342

8 - Pleura, Chest Wall, and Diaphragm healing ant erior rib f rac t ure (ar r ow ) in t his 46- y ear- old w oman f ollow ing a median st ernot omy f or heart t ransplant at ion.

TUMORS OF THE CHEST WALL Bot h benign and malignant t umors may arise f rom any of t he sof t t issues or bones of t he c hest w all. Bronc hogenic and breast c arc inoma, t hy moma, ly mphoma, and mesot helioma may inv olv e t he c hest w all by direc t ext ension (158). Almost any primary malignanc y c an met ast asize t o t he sof t t issue (see F ig. 8- 64) or bones (F ig. 8- 99) of t he t horac ic skelet on. Alt hough pat ient s f requent ly present w it h a painf ul or palpable mass, some are asy mpt omat ic and t he t umor is disc ov ered inc ident ally (369). Most malignant c hest w all t umors are assoc iat ed w it h c hest w all pain. Bot h CT and MRI c an ident if y t he presenc e and delineat e t he ext ent of sof t t issue inf ilt rat ion and assess bone P.621 inv olv ement by c hest w all t umors. Oc c asionally , it may be dif f ic ult t o det ermine w het her a mass arises f rom t he pleura or c hest w all, as bot h c an f orm lent ic ular masses along t he lung margin. Bone dest ruc t ion is def init iv e ev idenc e of c hest w all inv olv ement , w hile ext ension bet w een ribs is highly suggest iv e. As w it h inf ec t ious proc esses, MRI is more sensit iv e in det ec t ing bone marrow inv olv ement and t he ext ent of sof t t issue inv olv ement , and bet t er f or t issue c harac t erizat ion, w hereas CT is bet t er at ident if y ing c alc if ied t umor mat rix and c ort ic al bone dest ruc t ion (257,484). Neit her prov ides a spec if ic hist ologic diagnosis f or most lesions of sof t - t issue densit y , so biopsy is usually required.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1343

8 - Pleura, Chest Wall, and Diaphragm F igure 8- 94 Cost ov ert ebral junc t ion simulat ing a nodule. A: A 58- y ear- old

man suspec t ed of hav ing a pulmonary nodule bec ause of an opac it y seen on a lat eral c hest radiograph (ar r ow ). B: T he CT examinat ion show s t hat t his opac it y w as a result of t he superimposit ion of prominent , sc lerot ic c ost ov ert ebral junc t ions (ar r ow ).

F igure 8- 95 Ost eoc hondroma of rib. A pleural- based opac it y w as not ed ov erly ing t he right lung apex on a c hest radiograph. CT image w indow ed f or bone det ail demonst rat es a sc lerot ic lesion arising f rom t he post erior aspec t of t he right sec ond rib (ar r ow ), c harac t erist ic of a benign ost eoc hondroma.

Benign lesions t y pic ally c annot be dist inguished def init iv ely f rom malignant lesions, bec ause neit her size nor sharpness of t he border is a reliable diagnost ic c rit erion. F or example, subc ut aneous met ast ases may appear w ell c irc umsc ribed, and elast of ibroma dorsi, a benign c onnec t iv e t issue mass oc c urring in elderly pat ient s t hat arises bet w een t he c hest w all and t he inf erior angle of t he sc apula, usually P.622 appears as an inf ilt rat ing, sof t t issue densit y mass (42,303). How ev er, c ert ain f eat ures allow a spec if ic diagnosis, suc h as t he f at at t enuat ion of lipomas and t he presenc e of phlebolit hs and c harac t erist ic v asc ular enhanc ement of c av ernous hemangiomas (483). In addit ion, alt hough many f indings are nonspec if ic , rapid grow t h, inv asion of adjac ent st ruc t ures, and anc illary f indings suc h as pulmonary met ast ases c learly suggest malignanc y (419).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1344

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 96 Chest w all c ollat erals. A, B: CT images obt ained during a right upper ext remit y c ont rast injec t ion in a pat ient w it h superior v ena c av a obst ruc t ion result ing f rom f ibrosing mediast init is show enlarged c ollat eral v essels (ar r ow s) in t he c hest w all, enhanc ing on t he side of t he injec t ion. Enhanc ement of t he azy gos (open ar r ow ) and int erc ost al and paraspinal (ar r ow heads) v eins as a c ollat eral rout e of sy st emic v enous ret urn is seen. Not e f ibrosis surrounding t he great v essels in (A) and c alc if ied sof t t issue (w av y ar r ow ) f rom old granulomat ous disease oblit erat ing t he superior v ena c av a in (B). C : Coronal maximum- int ensit y projec t ion of a slab t hrough t he ant erior c hest w all show s t he enhanc ing c ollat eral v eins on t he right , and t heir inf erior ext ent t o t he upper abdomen. Xiphoid and lef t - sided ant erior rib c art ilage c alc if ic at ion is inc luded in t he slab.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1345

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 97 Ac t inomy c osis w it h empy ema nec essit at is. A, B: Cephaloc audal CT images in a 48- y ear- old man show ext ensiv e pleural sof t t issue t hic kening and f luid on t he right , an adjac ent ant erior c hest w all f luid c ollec t ion w it h rim enhanc ement (ar r ow s) and adjac ent sof t t issue t hic kening, and peripheral right lung base c onsolidat ion. T he pat ient present ed w it h a f luc t uant right c hest w all mass af t er a 5- mont h hist ory of f ev ers, c hills, night sw eat s, c ough, and c hest pain, f ollow ing sev eral nondiagnost ic perc ut aneous pleural and bronc hosc opic lung biopsies. Ac t inomy c es w as ident if ied f ollow ing drainage of c hest w all absc ess and empy ema.

Bone Tumors CT is usef ul in t he assessment of solit ary , aggressiv e- appearing bone lesions and f or ev aluat ing bone inv olv ement by adjac ent t umors, but it is of lesser v alue f or assessing nonaggressiv e or mult iple lesions, in w hic h c ase plain f ilms may suf f ic e (99). Primary benign and malignant t umors of t he ribs hav e an equal inc idenc e, but primary P.623 t umors of t he st ernum are more of t en malignant t han benign (419). Alt hough plain c hest and bone radiography and radionuc lide bone sc int igraphy usually are used f or det ec t ion, CT may disc lose a prev iously undiagnosed lesion. Oc c asionally , CT may demonst rat e a rib lesion t hat had been suspec t ed t o be a parenc hy mal nodule on a c hest radiograph.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1346

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 98 Empy ema nec essit at is due t o My c obac t er ium t uber c ulosis. A: CT image show s a small, rim- enhanc ing f luid c ollec t ion (ar r ow ) in t he lef t post erior c ost ophrenic sulc us result ing f rom a t uberc ulous empy ema. B: Sc an slight ly c audal t o (A) show s inf erior ext rapleural ext ension of sof t t issue t hic kening (ar r ow ), w it h erosion and sc lerosis of adjac ent post erior lef t rib. C : Sc an c audal t o (B) rev eals rim- enhanc ing f luid c ollec t ion in t he post erolat eral lef t c hest w all result ing f rom c ont iguous ext ension of inf ec t ion f rom t he pleural spac e.

F igure 8- 99 Met ast at ic renal c ell c anc er. Dest ruc t iv e mass inv olv es t he lef t sc apula.

Benign Bone Tumors CT rarely prov ides addit ional usef ul inf ormat ion on most benign bone lesions ot her t han reassuranc e t hat it is c learly a benign dev elopment al, degenerat iv e, or post t raumat ic abnormalit y (114). Ost eoc hondr om as

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1347

8 - Pleura, Chest Wall, and Diaphragm (exost oses), t he most c ommon benign t umor of c art ilage and bone (225,526), are benign exophy t ic projec t ions of c ort ic al bone (see F ig. 8- 95). In t he ribs, t hey f requent ly oc c ur at t he c ost oc hondral junc t ion; t hey are usually lobulat ed w it h a c art ilaginous c ap (419), t hough c ont inuit y bet w een t he

c ort ex and medulla of t en is not v isible in rib lesions on CT or MR images (483). T he c art ilaginous c ap has inc reased signal int ensit y on T 2- w eight ed MR images (276,483), t hough if c alc if ied may be depic t ed bet t er by CT (483). Pain, bone erosion, irregular c alc if ic at ion, and t hic kening of t he c art ilaginous c ap of more t han 2 c m raise suspic ion of malignant t ransf ormat ion t o c hondrosarc oma (318,483,526); t he risk is great est in mult iple heredit ary exost oses (0.5% t o 2.0%) (318), an aut osomal dominant c ondit ion. Benign bone islands (see F ig. 7- 21) appear as small sc lerot ic f oc i and c ommonly oc c ur in t he c anc ellous bone of t he ribs, shoulder girdle, and spine. Enc hondr om as are benign bone lesions t hat are t y pic ally w ell def ined, lobulat ed, expansile, and c ont ain dif f use, st ippled, or c art ilage mat rix c alc if ic at ion (318,419). T hey also are among t he more c ommon benign t umors of t he ribs and st ernum. T hough benign, c omplic at ions inc lude pat hologic f rac t ure and an inc reased risk f or malignant degenerat ion w hen mult iple and dif f use, as in Ollier disease (enc hondromat osis) or Maf f uc c i sy ndrome (enc hondromat osis, hemangiomas) (318). F ibr ous dy splasia is a benign dev elopment al anomaly usually disc ov ered in y oung adult hood and is monost ot ic more of t en t han poly ost ot ic (255,483). T he rib c age is a v ery c ommon loc at ion, and t he c lav ic le is oc c asionally inv olv ed (225,255,483). CT f eat ures inc lude c ent ral, f usif orm, ly t ic expansion, ground glass at t enuat ion or irregular, amorphous c alc if ic at ion, and t hinning of t he c ort ex (F ig. 8- 100) (225,419,483). On MR images, lesions are hy point ense w it h T 1 w eight ing and v ariable in signal w it h T 2 w eight ing (224,495). Aneur y sm al bone c y st s present as expansile ly t ic lesions, sharply demarc at ed by a t hin shell of periost eum (419). T hey c ont ain mult iple blood- f illed c y st s and hav e t he pot ent ial t o ext end bey ond t heir sc lerot ic margin int o adjac ent sof t t issues, w hic h may make t hem hard t o dist inguish f rom sarc omas (483). Most are seen in pat ient s y ounger t han 30 y ears (262,483). F luid- f luid lev els may be seen on CT or MR images, result ing f rom t he hemorrhagic c y st c ont ent s, but are not spec if ic bec ause t hey also c an oc c ur in simple bone c y st s, giant c ell t umors, c hondroblast omas, t elangiec t at ic ost eosarc omas, and ot her t umors (205,483,493). A rim of low signal is t y pic ally seen on MR images (36,526). Areas hist ologic ally resembling aneury smal bone c y st may be f ound w it hin

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1348

8 - Pleura, Chest Wall, and Diaphragm ot her t umors, suc h as giant c ell t umor, c hondromy xoid f ibroma, f ibrous dy splasia, and t elangiec t at ic ost eosarc oma (F ig. 8- 101), so adequat e biopsy sampling is import ant (535).

Eosinophilic gr anulom a is a benign dest ruc t iv e bone lesion of unknow n et iology t hat f requent ly inv olv es t he ribs and st ernum (289,526). It t y pic ally appears as a geographic ly t ic def ec t w it h w ell- def ined margins. T here may be some expansion (419). Hem angiom a present s as an expansile lesion w it h int ernal t rabec ulat ions and an int ac t c ort ic al margin (366). CT c an rev eal t y pic al “ honey c omb,” “ soap bubble,” or “ sunburst ” appearanc es; bot h CT and MRI c an show lipomat ous port ions (526). Giant c ell t um or s are usually f ound in y oung adult s, af t er epiphy seal c losure. Rare in t he t horax (344), t hey c an arise in t he st ernum, c lav ic le, and ribs as ost eoly t ic , expansile lesions w it h c ort ic al t hinning (483). Sof t t issue ext ension may be seen w it h CT or MRI in a subst ant ial minorit y of giant c ell t umors, and f luid lev els or aneury smal bone c y st c omponent s are also relat iv ely c ommon (279,344,526). Signal c harac t erist ic s are generally low t o isoint ense c ompared w it h musc le on T 1- w eight ed MR images, and het erogeneously high on T 2w eight ed images, t hough rec ent hemorrhage may c ause high signal areas on T 1- w eight ed images and hemosiderin may c ause v ery low signal areas on bot h T 1- and T 2- w eight ed images (17). T hough c onsidered benign, t hey may be loc ally aggressiv e w it h rec urrenc e rat es of 30% t o 50% (279). Ot her rare benign bone t umors t hat hav e been desc ribed in t he c hest w all inc lude c hondr oblast om a (318) and c hondr om y xoid f ibr om a (483). Bot h lesion t y pes are expansile w it h c ort ic al sc alloping. Ext r am edullar y hem at opoiesis (see F ig. 8- 44) c an result in paraspinal masses and hy pert rophy of t he medullary c av it y of t he ribs. T his c an be seen in t halassemia, heredit ary spheroc y t osis, my elosc lerosis, and ot her c auses of anemia.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1349

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 100 F ibrous dy splasia. A: Chest radiograph. B: CT sc an show s expansile ly t ic lesions inv olv ing t he lef t ant erior t hird (3) and f ourt h (4) ribs in a 29- y ear- old w oman.

P.624

Malignant Bone Tumors T he most c ommon c ause of a dest ruc t iv e lesion in t he rib or st ernum in adult s is met ast at ic disease f ollow ed by mult iple my eloma. Bot h proc esses generally appear as areas of subt le or c omplet e ly t ic dest ruc t ion of t he c anc ellous and c ort ic al bone (F igs. 8- 82, 8- 83, 8- 99, 8- 102, and 8- 103) (257,521). My eloma produc es ost eoly t ic lesions w it h w ell- def ined margins. Sc lerosis may be seen t oo, but is more f requent in healing f rac t ures or f ollow ing t reat ment (484). A sof t t issue mass may ac c ompany t he bone dest ruc t ion, part ic ularly w it h my eloma or plasmac y t oma and t hy roid and renal c ell c arc inoma (225). Widespread met ast at ic disease or my eloma may present as a dif f use, mot t led appearanc e. Blast ic met ast ases are usually produc ed by prost at e and neuroendoc rine c arc inomas and may c ause dif f use sc lerosis (F ig. 8- 104). Met ast at ic inv olv ement may oc c ur hemat ogenously or by direc t spread suc h as f rom lung c anc er; bone dest ruc t ion prov ides unequiv oc al ev idenc e of c hest w all inv asion (see F ig. 7- 42).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1350

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 101 T elangiec t at ic ost eosarc oma w it h aneury smal bone c y st element s. CT image show s sof t t issue mass w it h small areas of low at t enuat ion replac ing post erior lef t rib.

Primary malignant t umors of t he t horac ic skelet on inc lude c hondrosarc omas, ost eosarc omas, f ibrosarc omas, and round c ell t umors. Chondr osar c om a is t he most c ommon primary malignant t umor of t he c hest w all, more f requent ly arising f rom t he ant erior ribs t han t he st ernum, c lav ic le, or sc apula (318,521). Peaks of prev alenc e are bef ore 20 y ears of age and around 50 y ears of age (318,521). Most are primary , but some arise f rom benign lesions, suc h as ost eoc hondroma or enc hondroma (318,484). Chondrosarc omas of t en present as large, lobulat ed t umors w it h assoc iat ed c ort ic al bone dest ruc t ion and int ernal c alc if ic at ions, P.625 most f requent ly inv olv ing an ant erior rib near t he c ost al c art ilage junc t ion (16,225,419). Sec ondary c hondrosarc omas may be ly t ic (318). On MRI, t y pic al c hondrosarc omas hav e signal int ensit y similar t o t hat of musc le w it h T 1 w eight ing and similar t o or higher t han t hat of f at w it h T 2 w eight ing and het erogeneous enhanc ement w it h gadolinium; my xoid v ariant s lac k c alc if ic at ion and may hav e v ery high signal int ensit y on T 2- w eight ed images (F ig. 8- 105) (483,500).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1351

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 102 Met ast at ic renal c ell c arc inoma. Large met ast at ic t umor mass (m) dest roy ing and expanding a rib, w it h inhomogeneous enhanc ement . A small lef t pleural ef f usion (Ef ) is present .

Ost eosar c om as (F ig. 8- 106) usually oc c ur in t he sec ond and t hird dec ades, t hough t he parost eal f orm is f ound in t he sec ond t o f if t h dec ades (225). A mixed ly t ic and sc lerot ic pat t ern is t y pic al, depending on t he amount of bone produc t ion by t he t umor; t he parost eal f orm at t ac hes t o t he out er margin of t he c ort ex (225). T he nonspec if ic MR f indings inc lude signal int ensit y higher t han t hat of musc le w it h T 1 w eight ing, mixed but predominant ly high signal w it h T 2 w eight ing, and het erogeneous enhanc ement (484). Chest w all t umors prev iously know n as primit iv e neuroec t odermal or Askin t umors are aggressiv e f orms of Ew ing sar c om a (484,524). T hese small c ell t umors oc c ur most of t en in c hildren and y oung adult s. T hey usually arise in t he rib, sc apula, c lav ic le, or st ernum, but may be ext raskelet al. Masses may be large, w it h inhomogeneous CT at t enuat ion result ing f rom areas of hemorrhage or nec rosis, w it h or w it hout

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1352

8 - Pleura, Chest Wall, and Diaphragm c alc if ic at ion. On T 1- w eight ed MR images, t he signal int ensit y is usually t he

same as or great er t han t hat of musc le and may be het erogeneous, and t here is marked enhanc ement ; on T 2- w eight ed images, het erogeneous high signal is seen.

F igure 8- 103 Rec urrent Hodgkin disease, sarc omat oid v ariant . Large c hest w all mass dest roy s ant erior right rib.

Soft Tissue Tumors A v ariet y of t umors c an arise w it hin t he sof t t issues of t he c hest w all. Primary t umors are t y pic ally of mesenc hy mal origin and may originat e f rom t he f at , f ibrous, v asc ular, neural, musc ular, or dermal t issues. CT rarely allow s a def init iv e diagnosis of masses ot her t han lipomas, but c an play an P.626 import ant role in det ermining t he ext ent of t he t umor and inv olv ement of adjac ent st ruc t ures. Dist inc t ion bet w een benign and malignant masses w it h MRI also is not reliable, t hough a c apsule or pedic le, smoot h margins, and homogeneous signal int ensit y are more suggest iv e of a benign lesion, w hile irregular or ill- def ined margins, het erogeneous signal int ensit y , and musc le, bone, or v asc ular inv asion f av or a malignant lesion; how ev er, c hest w all inf ec t ion and hemat oma also may hav e irregular margins and het erogeneous signal, mimic king a malignant lesion (134). Bec ause of it s great er sof t t issue c ont rast , MRI generally is t he pref erred radiologic modalit y f or ev aluat ing P.627

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1353

8 - Pleura, Chest Wall, and Diaphragm t he ext ent of sof t t issue t umors, alt hough CT has great er spat ial resolut ion and c an bet t er det ec t c alc if ic at ions and bone dest ruc t ion.

F igure 8- 104 Widespread blast ic bone met ast ases f rom neuroendoc rine c arc inoma, w ell seen on CT image w it h lung w indow set t ings.

F igure 8- 105 Low - grade c hondrosarc oma w it h my xoid f eat ures. A: Post c ont rast , t ransv erse, T 1- w eight ed MR image demonst rat es a lobulat ed mass (m) w it h v ery low signal int ensit y , smoot h margins, sept at ions, and minimal rim enhanc ement arising in t he ant erior c hest w all. B: Sagit t al T 2-

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1354

8 - Pleura, Chest Wall, and Diaphragm w eight ed image demonst rat es a lobulat ed mass (m) of high signal int ensit y . Signal c harac t erist ic s suggest a c y st ic or my xoid t umor.

F igure 8- 106 Ost eosarc oma. A, B: Cephaloc audal CT images show lef t lat eral rib dest ruc t ion by a nonspec if ic sof t t issue mass.

Benign Soft Tissue Tumors Lipom as are t he most c ommon sof t t issue t umors inv olv ing t he c hest w all. T hey may be subc ut aneous, int ramusc ular, or ext rapleural; rarely , t hey are inf ilt rat ing and dif f use and t he t erm lipom at osis of t he c hest w all is most appropriat e. T hey c an present as a palpable mass, and on CT or MRI may be nearly indist inguishable f rom surrounding f at (F ig. 8- 107). When a lipoma oc c urs in t he ext rapleural f at , it c an displac e pleura and mimic a pleural or pulmonary mass on c onv ent ional radiography (see F ig. 8- 52). A t ransmural lipoma c an w iden an int erc ost al spac e and produc e pressure erosion on t he adjac ent ribs (123,516). Lipomas usually hav e sharply def ined margins, v ery lit t le arc hit ec t ure exc ept f or a t hin c apsule or sept at ions, and oc c asionally c ont ain small c alc if ic at ions. T hey are easily diagnosed w it h CT by t heir c harac t erist ic , relat iv ely homogeneous f at at t enuat ion (- 80 HU t o - 90 HU). T hey f ollow t he signal int ensit y c harac t erist ic s of subc ut aneous f at on all MRI sequenc es, demonst rat ing high signal int ensit y on T 1- w eight ed images, int ermediat e signal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1355

8 - Pleura, Chest Wall, and Diaphragm int ensit y on T 2- w eight ed images, and low signal int ensit y w it h short T 1

(inv ersion t ime) inv ersion rec ov ery (ST IR) and f at sat urat ion t ec hniques. T hey hav e no malignant pot ent ial but may be resec t ed f or c osmet ic reasons. In c omparison, liposarc omas are t y pic ally inhomogeneous, c ont aining sof t t issue at t enuat ion c omponent s in addit ion t o or inst ead of f at in t he st roma, and are generally large and inf ilt rat ing. T hey are usually dist inguished c onf ident ly f rom a benign lipoma on CT or MR images; on v ery rare oc c asions, a w elldif f erent iat ed liposarc oma might simulat e a benign lipoma. Neur ogenic t um or s, inc luding sc hw annomas, neurof ibromas, and neuroblast omas, c an be seen in t he c hest w all inv olv ing t he int erc ost al nerv es and spinal nerv e root s. Sc hw annomas (neurilemomas, neurinomas) (483) arise f rom t he nerv e sheat hs, are usually slow grow ing, and of t en are inc ident ally disc ov ered on c hest radiographs obt ained f or unrelat ed reasons. T hese t umors are usually w ell- c irc umsc ribed, round, ov oid, or lobulat ed masses (F ig. 8- 108). On CT , t hey usually hav e at t enuat ion similar t o or slight ly less t han t hat of musc le and enhanc e mildly w it h c ont rast . Any areas of c y st ic degenerat ion (F ig. 8- 109) are low er in at t enuat ion and unenhanc ing. On MR images, sc hw annomas hav e signal int ensit y similar t o or slight ly higher t han t hat of musc le w it h T 1 w eight ing and markedly higher t han t hat of musc le w it h T 2 w eight ing (see F ig. 8- 108). T he nerv e of origin may be seen t apering f rom a margin of t he mass. Small t umors t end t o enhanc e unif ormly w it h gadolinium, w hile larger t umors may enhanc e het erogeneously (483).

F igure 8- 107 Lipoma. Well- demarc at ed f at at t enuat ion lef t post erior c hest w all mass (m) w it h minimal st romal c omponent s and v essels.

Neurof ibromas are most c ommonly (t hough not alw ay s) assoc iat ed w it h t y pe 1 neurof ibromat osis or mult iple plexif orm neurof ibromas (483). T hey are slight ly

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1356

8 - Pleura, Chest Wall, and Diaphragm low in at t enuat ion on CT , and enhanc e het erogeneously w it h int rav enous c ont rast . On MR images, many neurof ibromas hav e c harac t erist ic peripheral

high signal int ensit y and c ent ral low er signal int ensit y on T 2- w eight ed images, relat ed t o c ent ral c ellularit y and peripheral st romal mat erial, w hic h result s in c ent ral c ont rast enhanc ement (483). Oc c asionally , CT may be usef ul t o dist inguish c ut aneous neurof ibromas v isible on c hest radiography f rom pulmonary nodules. Plexif orm neurof ibromas may ext ensiv ely inf ilt rat e t he c hest w all. T hey of t en hav e a relat iv ely low at t enuat ion v alue approac hing t hat of w at er, f or a v ariet y of reasons, inc luding an abundant lipid c ont ent , my xoid mat rix, hy poc ellularit y , and/or regions of c y st ic degenerat ion (86,95). T his at t enuat ion dif f erenc e is emphasized f ollow ing int rav enous administ rat ion of c ont rast mat erial (257). Int ramusc ular neurof ibromas may be dif f ic ult t o delineat e w it h CT bec ause of limit ed sof t t issue c ont rast disc riminat ion, but c hest w all ext ent is readily ev aluat ed w it h MR bec ause of t heir high signal on T 2- w eight ed images (225). T he int raspinal ext ent of a neurogenic t umor usually c an be depic t ed w it h MRI, obv iat ing c ont rast my elography . T here is a risk of malignant degenerat ion of neurof ibromas (483), up t o 10% t o 20% in neurof ibromat osis, but lesions may st ill be benign ev en w hen inhomogeneous at t enuat ion is seen. Ganglioneur om as arise f rom t he sy mpat het ic ganglia, present ing as w ellc irc umsc ribed paraspinal masses. T hey may be homogeneous or het erogeneous in at t enuat ion on CT , w it h areas of homogeneous int ermediat e signal int ensit y separat ed by low signal bands on T 1- and T 2- w eight ed MR images, and c alc if ic at ions may be present (483). Paragangliomas also c an oc c ur in t he parav ert ebral region, t ending t o hav e homogeneous CT at t enuat ion and MR signal int ensit y , w it h marked enhanc ement (483). Cav er nous hem angiom as are benign v asc ular t umors f ound in t he skin, sof t t issues, and bones of t he c hest w all. CT rev eals a sof t t issue mass of het erogeneous at t enuat ion depending on it s v asc ular, f at , and f ibrous c omponent s, P.628 and c an depic t c harac t erist ic phlebolit hs w hen present (F ig. 8- 110) (483). Hemangiomas c ont ain t ort uous v essels t hat enhanc e f ollow ing c ont rast administ rat ion. T he exc ellent sof t t issue c ont rast of MR best demonst rat es t he ext ent of hemangiomas. Signal int ensit y v aries depending on t he proport ion of v asc ular, f at , and f ibrous c omponent s, as w ell as t hrombus, hemosiderin, and old blood (249). Int ermediat e signal int ensit y and high signal areas w it h T 1

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1357

8 - Pleura, Chest Wall, and Diaphragm w eight ing and high signal w it h T 2 w eight ing are t y pic ally seen, w it h t ubular v essels depic t ed on f low - sensit iv e and c ont rast - enhanc ed sequenc es (225,249,483). T he more c omplex c av ernous hemangiomas may be dif f ic ult t o dif f erent iat e f rom ot her neoplasms bec ause of hemorrhage w it h assoc iat ed

hemosiderin, t hrombosis, and ext ensiv e hy alinizat ion (516). Bot h hemangiomas and ly mphangiomas may be dev elopment al anomalies rat her t han neoplasms (277).

F igure 8- 108 Sc hw annoma. A: CT image show s a smoot hly rounded mass (ar r ow ) at t he lef t lung apex, similar t o or slight ly low er t han musc le in at t enuat ion on t his unenhanc ed sc an. B: T 1- w eight ed c oronal MR image show s t hat t he mass (ar r ow ) is of homogeneous int ermediat e signal int ensit y and has an ext rapleural loc at ion w it h ext rapleural f at high signal int ensit y present along it s inf erior margin. C : T 2- w eight ed sagit t al MR image w it h f at sat urat ion show s c harac t erist ic high signal int ensit y of t he t umor (ar r ow ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1358

8 - Pleura, Chest Wall, and Diaphragm Ly m phangiom as present as masses t hat may be c onf used w it h hemangiomas (432). T hese masses are usually c y st ic and smoot hly marginat ed, being c omposed of sequest ered ec t at ic ly mphat ic t issue separat ed f rom t he

ly mphat ic drainage sy st em (432). T hey arise most f requent ly in t he nec k, may ext end int o t he mediast inum, c hest w all, or axilla, and of t en require surgic al resec t ion. T hey t y pic ally appear as near- w at er at t enuat ion c y st ic masses on CT , alt hough t hey may be of higher at t enuat ion bec ause of hemorrhage, prot einac eous subst anc e, or hemangiomat ous element s (277,330,382,444). Preoperat iv e planning inv olv es c aref ul ev aluat ion of t he f ull ext ent of ly mphangiomas t o minimize t he risk of rec urrenc e. T y pic ally hav ing t he signal c harac t erist ic s of w at er on all pulse sequenc es, ly mphangiomas are best ev aluat ed by MRI, w hic h is bet t er suit ed t o def ine t he ext ent and degree of inf ilt rat ion of adjac ent t issues; MRI also f requent ly rev eals t he int ernal sept at ions of P.629 t hese mult iloc ulat ed masses, w hic h are not show n by CT (249). How ev er, more int ermediat e signal in some ly mphangiomas on T 1- and T 2- w eight ed images also has been report ed (444).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1359

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 109 Sc hw annoma w it h c y st ic degenerat ion. A: Unenhanc ed CT image show s a smoot h, ov oid, lef t apic al mass of most ly low at t enuat ion, t hough lay ering higher at t enuat ion f luid is present in t he dependent aspec t . B: T 2- w eight ed t ransv erse MR image c learly rev eals a f luid–f luid lev el and an irregularly t hic kened w all, c onsist ent w it h a c y st ic or nec rot ic mass. C : T 1- w eight ed c oronal MR image af t er gadolinium administ rat ion show s marked enhanc ement of t he t hic kened w all w it h low signal f luid c ent rally . An inf ec t ed bronc hogenic c y st or ot her c av it ary neoplasm c ould hav e t he same appearanc e.

Sebac eous c y st s are c ommonly enc ount ered as low - at t enuat ion, c irc umsc ribed lesions w it hin t he subc ut aneous f at . Glom us t um or s c an oc c ur in t he c hest w all and are muc h more of t en benign t han malignant (436,483). CT f indings are nonspec if ic . My osit is ossif ic ans is unusual in t he c hest w all, so may be mist aken f or a malignant neoplasm w hen it oc c urs (244). As t he lesion mat ures, ident if ic at ion of a peripheral rim of c alc if ic at ion and ossif ic at ion

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1360

8 - Pleura, Chest Wall, and Diaphragm around a more luc ent region may suggest t he t rue nat ure of t he lesion; MRI c orrelat es inc lude a low signal int ensit y border and a c ent ral area c ont aining f at or high T 2 signal int ensit y (357).

Malignant Soft Tissue Tumors Sof t t issue sar c om as of t he c hest w all, inc luding desmoid t umor (F ig. 8- 111), malignant f ibrous hist ioc y t oma (F ig. 8- 112), f ibrosarc oma, rhabdomy osarc oma, leiomy osarc oma, malignant peripheral nerv e sheat h t umor, sy nov ial sarc oma, and ot her less c ommon sarc omas (F ig. 8- 113), all hav e a similar appearanc e on CT (225). T he f indings are t hose of nonspec if ic sof t t issue masses, w it h or w it hout low at t enuat ion areas of nec rosis, and v ariable, of t en het erogeneous enhanc ement . Oc c asionally , t he presenc e of f at allow s dist inc t ion of a w elldif f erent iat ed liposarc oma f rom ot her t umor t y pes. Bone, v essel, or musc le inv asion, or int rat horac ic ext ension, may be a c lue t o t he malignant nat ure of a c hest w all sarc oma. T here is enough ov erlap w it h benign lesions, how ev er, t hat t hey usually c annot be P.630 dist inguished w it h c omplet e c ert aint y using CT or MRI (F ig. 8- 114).

F igure 8- 110 Mult iple hemangiomas. Mult iple lobulat ed serpiginous masses (m) inv olv ing t he c hest w all, pleura, and mediast inum, w it h c alc if ic at ions seen in some port ions (ar r ow s).

Desm oid t um or s (see F ig. 8- 111) are c onsidered low - grade f ibrosarc omas (249,484). T hey are a diagnost ic and t herapeut ic c hallenge as t hey t end t o be

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1361

8 - Pleura, Chest Wall, and Diaphragm loc ally aggressiv e and t o rec ur w hen inadequat ely exc ised (77,369), t hough t hey do not met ast asize (225,484). T hey lac k a c apsule and may inf ilt rat e ext ensiv ely int o surrounding t issue and ev en int rat horac ic ally , ac c ount ing f or t he dif f ic ult y in f ull delineat ion bec ause of t heir ill- def ined margins. Wide surgic al resec t ion is required t o t ry t o prev ent rec urrenc e (77). On CT sc ans, desmoid t umors are of sof t t issue at t enuat ion w it h v ariable enhanc ement . On MRI sc ans, t hey hav e signal int ensit y similar t o t hat of musc le w it h T 1

w eight ing. Wit h T 2- w eight ing t hey are most ly int ermediat e in signal int ensit y , but may hav e v ery low signal areas bec ause of c ollagen, or v ery high signal areas (77,127,484). T hey may c ause pressure erosions on bone, but do not usually inv ade bone (484). Ly m phom a inv olv es t he c hest w all in 10% t o 15% of pat ient s and c an arise f rom int erpec t oral or lat eral t horac ic ly mph nodes or ribs, int ernal mammary nodes, or by ext ension of c ont iguous mediast inal or pleuropulmonary disease (F ig. 8- 115) (387,516). Ident if ic at ion of P.631 t he loc at ion and ext ent of inv asion c an impac t t herapy by alt ering t he radiat ion port s c hosen (73,82,387). Primary musc le ly mphoma t ends t o be inf ilt rat iv e w it hout c onf inement t o musc le c ompart ment s (280). Ly mphoma t y pic ally has at t enuat ion similar t o t hat of musc le, and enhanc es slight ly af t er int rav enous c ont rast administ rat ion (484). In my c osis f ungoides, CT may rev eal skin t hic kening and t he dept h of subc ut aneous ext ension (302). MRI, on w hic h ly mphomas generally appear similar t o or higher t han f at in signal int ensit y on T 2- w eight ed images, is more sensit iv e t han CT f or det ec t ing c hest w all inv olv ement by ly mphoma (39,73,280). Met ast at ic c anc er, espec ially melanoma (F ig. 8- 116), also c an inv olv e t he sof t t issues of t he c hest w all.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1362

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 111 Desmoid t umor. A: CT show s relat iv ely w ell- demarc at ed, mildly enhanc ing, right axillary mass (m) inv ading t hrough t he c hest w all int o t he ext rapleural spac e. B: T 1- w eight ed c oronal MR image rev eals t he longit udinal ext ent of t he mass (m). C : T 2- w eight ed t ransv erse MR image rev eals t he int rat horac ic ext ent of t he mass (m). T he het erogeneous signal int ensit y and part ly inf ilt rat iv e margins of t he mass on bot h sequenc es suggest an aggressiv e proc ess, but are nonspec if ic f indings. Low signal int ensit y w it h T 2 w eight ing, somet imes seen in desmoid t umors bec ause of organized f ibrosis, w as not present in t his c ase.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1363

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 112 Malignant f ibrous hist ioc y t oma. A sof t t issue at t enuat ion mass (m), w it h a low er densit y c ent er bec ause of nec rosis, enlarges t he rhomboid major musc le.

Chest Wall Invasion Primary pulmonary or pleural neoplasms may sec ondarily inv olv e t he pariet al pleura and c hest w all. Pleural or c hest w all inv asion in lung c anc er raises t he t umor st age and adv ersely af f ec t s prognosis. T he presenc e of inv asion requires en bloc resec t ion of t he c hest w all w it h t he t umor, but is not a c ont raindic at ion t o surgery and does not det ermine operabilit y . How ev er, preoperat iv e ident if ic at ion of c hest w all inv asion may aid surgic al planning. Adv anc es in c hest w all rec onst ruc t ion hav e f ac ilit at ed pot ent ially c urat iv e ext ensiv e resec t ions f or primary malignant neoplasms inv olv ing t he c hest w all (369). F or t umors in t he superior sulc us, it is import ant t o det ermine w het her inv asion ext ends int o t he c hest w all t o inv olv e t he brac hial plexus or subc lav ian art ery . In some c ases, shrinking an inv asiv e superior sulc us t umor by using neoadjuv ant c hemot herapy and radiat ion t herapy allow s resec t ion t o be perf ormed. Post operat iv ely , c hest w all prost heses of poly propy lene mesh molded t o t he c hest w all c ont our w it h met hy l met hac ry lat e are not v isible radiographic ally , but are easily depic t ed by CT w it h at t enuat ion great er t han t hat of bone (147).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1364

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 113 Epit helioid sarc oma. Hy perv asc ular lef t axillary mass (m) displac ing t he pec t oralis major musc le (ar r ow heads) ant eriorly and inv ading t he ext rapleural spac e (ar r ow s).

F igure 8- 114 Low - grade sarc oma. A mass w it h relat iv ely smoot h borders is seen w it hin t he musc ulat ure of t he upper bac k. T he homogeneous, near- w at er at t enuat ion might suggest t he possibilit y of a f luid c ollec t ion or c y st ic lesion.

T he only reliable CT sign of c hest w all inv asion by a mass c ont ac t ing t he pariet al pleura is rib or spine dest ruc t ion (see F ig. 7- 42). P.632

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1365

8 - Pleura, Chest Wall, and Diaphragm

Abnormal sof t t issue ext ending ext ernal t o t he margin of t he ribs also support s c hest w all inv asion (F ig. 8- 117) (180). Ot her signs, suc h as obt use angles of t he mass w it h t he c hest w all, more t han 3 c m of c ont ac t of t he mass w it h t he pleural surf ac e, pleural t hic kening adjac ent t o t he mass, abnormal ext rapleural f at at t enuat ion, and asy mmet ry of t he c hest w all sof t t issues, of t en oc c ur w it h inv asion by lung c anc er, but c an also be a result of inf lammat ory c hanges, sc arring, or asy mmet ric pat ient posit ioning (158,516). T hus, in most c ases CT is of somew hat limit ed v alue in ident if y ing c hest w all inv asion.

F igure 8- 115 Chest w all ly mphoma. CT image, obt ained in a 74- y ear- old man w ho not ic ed a painless c hest w all lump enlarging ov er 4 t o 5 mont hs, rev eals an ill- def ined sof t t issue mass enlarging t he lef t pec t oralis musc ulat ure. T he t umor erodes t he lef t lat eral aspec t of t he st ernum adjac ent t o t he region of t he lef t int ernal mammary ly mph nodes.

F igure 8- 116 Melanoma met ast ases. Numerous small, rounded, sharply c irc umsc ribed nodules are present t hroughout t he subc ut aneous f at of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1366

8 - Pleura, Chest Wall, and Diaphragm c hest w all.

Sc anning during v arious phases of t he breat hing c y c le (251,343,426,455), or af t er induc ed pneumot horax (512,531), has been used t o exc lude c hest w all inv asion in lung c anc er. T umor mov ement of one t hird t o one half of a v ert ebral lev el bet w een deep inspirat ion and expirat ion appears t o indic at e lac k of inv asion. Similar reliabilit y f or exc luding c hest w all inv asion has been f ound using dy namic c ine MRI during breat hing (426). Bec ause f ixat ion of a t umor t o t he c hest w all may be a result of benign adhesions, and noninv asiv e upper lobe t umors may not mov e w it h respirat ion, lac k of mov ement does not prov ide def init iv e ev idenc e of inv asion. T he ac c urac y of MRI in ident if y ing c hest w all inv asion has been f ound t o be equal t o (513) or great er t han t hat of CT (189,249,368). Signs of c hest w all inv asion inc lude t umoral signal int ensit y in t he c hest w all sof t t issues, ribs, or spine, and int errupt ion of t he ext rapleural f at plane by t umoral signal int ensit y (F ig. 8- 118). How ev er, abnormal c hest w all signal may be a result of inf lammat ion and is not alw ay s reliable. Gadolinium administ rat ion probably does not improv e diagnost ic ac c urac y (368). Whet her t he improv ed spat ial resolut ion f rom t he t ec hnologic al adv anc ement s of t hin- sec t ion mult idet ec t or CT or 3D MRI pulse sequenc es inc reases diagnost ic ac c urac y f or c hest w all inv asion has not been report ed. In ot her selec t ed pat ient s, MRI may be of v alue in assessing t he ext ent of ly mphomat ous c hest w all inv asion (39,73). On T 1- w eight ed images, f indings suggest iv e of c hest w all inv asion inc lude t he presenc e of ext rapleural t umoral signal int ensit y and int errupt ion of t he ext rapleural f at st ripe. Abnormally high signal in t he c hest w all sof t t issues on T 2- w eight ed images st rongly suggest s inv asion, alt hough again t he signal abnormalit y may be a result of reac t iv e inf lammat ion and edema rat her t han f rom t he t umor it self .

BREAST CT prov ides a c lear depic t ion of t he sof t t issues of t he c hest w all and axilla in addit ion t o t he lungs, mediast inum, and liv er, and in selec t ed pat ient s w it h adv anc ed disease may be of v alue f or st aging breast c arc inoma at present at ion (257,292,331). It is not used f or preoperat iv e st aging in all P.633 pat ient s diagnosed w it h breast c anc er, but may be of benef it in pat ient s w it h large t umors or palpable, f ixed axillary nodes w it h a high suspic ion of met ast at ic disease (449). CT also may be usef ul init ially if c hest w all inv asion

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1367

8 - Pleura, Chest Wall, and Diaphragm or int ernal mammary adenopat hy is st rongly suspec t ed, and posit iv e f indings

w ould impac t radiat ion t herapy planning (292). Axillary ly mph node inv olv ement is t y pic ally det ermined t hrough phy sic al examinat ion and biopsy . A t ec hnique of CT ly mphography using w at er- soluble iodinat ed c ont rast has been ev aluat ed f or sent inel ly mph node mapping in pat ient s w it h early - st age breast c anc er (324,476,481). T he 3D depic t ion of sent inel ly mph nodes and t heir af f erent v essels may improv e t he biopsy guidanc e c urrent ly prov ided by radioisot ope and dy e injec t ion met hods. Int ernal mammary ly mph nodes c annot be assessed by phy sic al examinat ion; met ast ases should be suspec t ed if t hey are larger t han about 5 mm on CT , w hile axillary nodes may be up t o about 14 mm (88).

F igure 8- 117 Mesot helioma w it h c hest w all inv asion. A, B: Dif f use pleural t umor ext ends int o t he c hest w all t hrough mult iple int erc ost al spac es (ar r ow s). Not e small peric ardial ef f usion, small lef t pleural ef f usion, and enhanc ing lef t low er lobe at elec t asis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1368

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 118 Panc oast t umor w it h c hest w all inv asion. T ransv erse T 1w eight ed MR images w it hout (A) and w it h (B) int rav enous gadolinium in a 56y ear- old w oman w it h lef t upper ext remit y pain rev eal a het erogeneously enhanc ing sof t t issue mass in t he superior sulc us on t he lef t . Abnormal signal int ensit y and enhanc ement in t he T - 2 v ert ebra (ar r ow s) and lef t sec ond rib (ar r ow heads) and loss of t he ext rapleural f at plane indic at e c hest w all inv asion. C : T 1- w eight ed t ransv erse MR image slight ly more c audal rev eals t umor ext ending int o t he spinal c anal (ar r ow ).

An inc ident al breast mass may be disc ov ered on a CT examinat ion perf ormed f or ot her reasons (F ig. 8- 119). Unf ort unat ely , t he CT appearanc e usually is nonspec if ic , and mammography or ult rasound or biopsy , or a c ombinat ion, generally is required t o f urt her ev aluat e t he mass. T his limit ed spec if ic it y and t he imprac t ic al requirement f or int rav enous c ont rast administ rat ion t o det ec t c arc inomas w it h a high sensit iv it y eliminat es CT as a usef ul met hod of sc reening f or breast c arc inoma (81), t hough low - dose CT may improv e c ont rast sensit iv it y in dense breast s c ompared w it h mammography at dose

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1369

8 - Pleura, Chest Wall, and Diaphragm lev els c omparable t o t hose of mammography (54). Nev ert heless, it has been

show n t hat mult idet ec t or dy namic CT c an depic t many breast c anc ers (F ig. 8120) (214,441). F eat ures of malignanc y in breast lesions ident if ied on CT inc lude spic ulat ed and irregular margins, irregular shape, skin t hic kening, and dy namic c ont rast enhanc ement (214,246,441). Ly mphoma (F ig. 8- 121) and met ast at ic disease inv olv ing t he breast are rare, possibly bec ause of t he small amount of P.634 ly mphoid t issue in t he breast and inc reasing f ibrous t issue and relat iv ely poor blood supply af t er t he f ourt h dec ade; are more likely t o be mult if oc al and bilat eral; and are not t y pic ally assoc iat ed w it h spic ulat ion or mic roc alc if ic at ion (246,530). Sarc omas also rarely oc c ur.

F igure 8- 119 Breast c arc inoma. Mass (m) det ec t ed inc ident ally on c hest CT examinat ion.

T he role of MRI in breast c anc er imaging is great er t han t hat of CT , but is st ill being def ined. Wit h t he use of dedic at ed breast c oils, t hin sec t ions, f at suppression t ec hniques, and gadolinium c ont rast administ rat ion, MRI is highly sensit iv e f or det ec t ing breast c anc er, approac hing 100% det ec t ion f or inv asiv e duc t al c arc inoma, t hough it appears t o be low er f or inv asiv e lobular c arc inoma and duc t al c arc inoma in sit u (50,336,365). Bec ause of ov erlap in

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1370

8 - Pleura, Chest Wall, and Diaphragm t he enhanc ement of malignant lesions and benign f indings, spec if ic it y has

t ended t o be low er (50,365). In one st udy , malignanc y dev eloped on f ollow - up of a lesion int erpret ed on breast MRI as “ probably benign” in 7% t o 10% of high- risk w omen, w hic h is great er t han t he 0.2% t o 2% f requenc y report ed w it h nonpalpable lesions c onsidered “ probably benign” by mammography (287). F eat ures t hat hav e been assoc iat ed w it h malignanc y inc lude spic ulat ed margins, enhanc ement (part ic ularly rim, het erogeneous, or along a duc t al dist ribut ion), and irregular shape (F ig. 8- 122) (274,287,435,457). Benign f indings t hat may enhanc e inc lude, t hough are not limit ed t o, f ibroadenomas (F ig. 8- 123), f ibroc y st ic c hange, duc t al hy perplasia, ly mph nodes, f ibrosis, and post biopsy c hanges (286,336,365,381). T he addit ion of prot on MR spec t rosc opy and perf usion MRI t o t he dy namic c ont rast - enhanc ed t ec hnique may improv e spec if ic it y (204). In preoperat iv e ev aluat ions of know n breast c anc er, MRI c an improv e t he ac c urac y of st aging by rev ealing unsuspec t ed mult if oc al or bilat eral lesions (see F ig. 8- 120), or musc le (F ig. 8- 124) or c hest w all inv asion (37,274,287,336,365,498). Proposed and pot ent ial uses of MRI in breast c anc er diagnosis at t his t ime t hus inc lude preoperat iv e st aging; breast c anc er det ec t ion in pat ient s w it h mammographic ally dense breast s, post operat iv e breast s, or P.635 ot herw ise dif f ic ult mammograms; ev aluat ion of pat ient s w it h axillary ly mph node met ast ases in w hom phy sic al examinat ion and mammography are negat iv e; sc reening of high- risk pat ient s; and ev aluat ion of pat ient s w it h a breast problem not diagnosed by ot her means (50,274,336,430,435).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1371

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 120 Inv asiv e duc t al c arc inoma. A: CT image show s mild enhanc ement of malignant right breast mass (ar r ow ). B: T 1- w eight ed, f at suppressed t ransv erse MR image demonst rat es marked enhanc ement and bet t er c onspic uit y of t he t umor (ar r ow ) relat iv e t o CT . C : At a dif f erent lev el f rom t he same image series as (B), an enhanc ing lesion (ar r ow ) t hat prov ed t o be anot her inv asiv e duc t al c arc inoma w as inc ident ally det ec t ed in t he lef t breast .

F igure 8- 121 Breast ly mphoma. Asy mpt omat ic , large, mobile, nonspec if ic sof t t issue mass in t he right breast prov ed t o be a B- c ell ly mphoma. At open biopsy , mass w as deep t o pec t oralis musc le.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1372

8 - Pleura, Chest Wall, and Diaphragm Posttherapy Evaluation

Bot h c ont rast - enhanc ed CT and MRI are pot ent ially usef ul f or det ermining t he loc al ext ent of primary breast c anc er and residual t umor af t er neoadjuv ant c hemot herapy t o shrink larger t umors. T his may assist in det ermining t he required ext ent of resec t ion w hen breast - c onserv ing surgery is c onsidered (6,7,215,294,351,373,409). T he sensit iv it y of MRI also may be of v alue in ev aluat ing f or residual t umor in pat ient s w it h posit iv e margins af t er lumpec t omy but no c orrelat e on mammography (336).

F igure 8- 122 Inv asiv e duc t al c arc inoma. F at - suppressed, gadoliniumenhanc ed MR image rev eals an int ensely enhanc ing, spic ulat ed mass in t he lef t breast due t o inv asiv e duc t al c arc inoma. Sev eral simple c y st s dev oid of signal are present in t he right breast .

T he CT appearanc e of t he c hest w all may be alt ered by surgery , c hemot herapy , and radiat ion t herapy used as t reat ment f or breast c anc er. Dif f erent t y pes of mast ec t omies, inc luding radic al, modif ied radic al, and lumpec t omy , result in disparat e appearanc es (229). Post operat iv e imaging demonst rat es t he asy mmet ric absenc e of breast and f at t y t issue, and, depending on t he t y pe of surgery , adjac ent musc les and ly mph nodes. Radic al mast ec t omy remov es t he breast and bot h pec t oral musc les and axillary ly mph nodes. In modif ied radic al mast ec t omy , t he pec t oralis major musc le is preserv ed; t he pec t oralis minor may or may not be remov ed. Lumpec t omy , or part ial mast ec t omy , inv olv es exc ision of t he breast t umor and surrounding t issue, w it h or P.636

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1373

8 - Pleura, Chest Wall, and Diaphragm w it hout sent inel ly mph node resec t ion or axillary ly mph node dissec t ion t hrough a separat e inc ision, depending on w het her t he c anc er is inv asiv e. F luid c ollec t ions, represent ing hemat omas and seromas, are c ommon in t he immediat e post operat iv e period. T hic kening, irregularit y , shagginess, and enhanc ement of a f luid c ollec t ion w all are c harac t erist ic s of a post operat iv e

absc ess. T here should be no loc alized sof t t issue mass eit her out side or inside t he ribs af t er resolut ion of t hese immediat e post operat iv e c hanges. Residual port ions of t he pec t oralis major musc le may remain at t he st ernal or c ost al at t ac hment and should not be mist aken f or rec urrent t umor (450). T he ov erly ing skin f ollow ing breast surgery should be less t han 5 mm t hic k in healt hy pat ient s (450).

F igure 8- 123 F ibroadenoma and inv asiv e duc t al c arc inoma. T 1- w eight ed, f at suppressed, gadolinium- enhanc ed t ransv erse MR images rev eal a small, lobulat ed, int ensely enhanc ing mass more peripherally (ar r ow ), and a larger, lobulat ed, int ensely enhanc ing mass c ent rally (open ar r ow ), bot h suspec t ed t o be malignant . T he c ent ral lesion represent ed inv asiv e duc t al c arc inoma, w hile t he peripheral lesion t urned out t o be a f ibroadenoma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1374

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 124 Breast c anc er inv ading musc le. T 1- w eight ed, post gadolinium t ransv erse (A) and T 2- w eight ed sagit t al (B) images, bot h w it h f at sat urat ion, show an inv asiv e duc t al c arc inoma of t he lef t breast grow ing int o t he underly ing pec t oral musc le (ar r ow s).

T he post mast ec t omy appearanc e may be c ompounded by c hanges of superimposed surgic al breast rec onst ruc t ion, an import ant c omponent of breast c anc er t reat ment (296). T issue expanders may be plac ed prior t o breast prost hesis insert ion. T he t ransv erse rec t us abdominis musc uloc ut aneous (T RAM) f lap is a c ommon rec onst ruc t ion t ec hnique used at many inst it ut ions and inv olv es t he t ransf er of f at , skin, and rec t us abdominis musc le ont o t he c hest w all (281,296). T he proc edure may be unilat eral or bilat eral; CT and MR f indings inc lude a rec onst ruc t ed breast of f at at t enuat ion lac king glandular t issue, w it h or w it hout subc ut aneous c urv ilinear sof t t issue bands represent ing de- epit helialized abdominal w all skin, surgic al c lips, and denerv at ion at rophy of t he rec t us musc le (109,281). When sy mpt oms suc h as pain or a palpable abnormalit y oc c ur, MRI c an be usef ul in c harac t erizing abnormalit ies in t he rec onst ruc t ed breast as benign, suc h as skin t hic kening, f ibrosis, f at nec rosis, and seromas, or malignant , suc h as loc al or axillary node t umor rec urrenc e (109). Radiat ion t herapy may produc e c hanges in t he appearanc e of t he skin, sof t t issues, and lung parenc hy ma. T here may be skin t hic kening up t o 1 c m, inf lammat ory c hanges, and inc reased at t enuat ion in t he residual breast t issue and subc ut aneous f at (450). T he sof t t issue c hanges t y pic ally oc c ur in t he f irst f ew mont hs f ollow ing t herapy and somet imes resolv e on f ollow - up sc ans; t hey should be c onf ined t o t he radiat ion port . Radiat ion- induc ed f ibrosis may

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1375

8 - Pleura, Chest Wall, and Diaphragm inv olv e t he brac hial plexus or axillary v essels and usually oc c urs w it hin 30 mont hs of t reat ment ; it is of t en dif f ic ult t o dif f erent iat e f rom t umor rec urrenc e on CT or MRI, alt hough t he lat t er generally is more usef ul. A CT -

guided biopsy may be needed t o c orroborat e or help exc lude rec urrenc e (131). T he radiat ion port s used are t angent ial t o t he c hest w all t o minimize radiat ion t o t he lung, and it is c ommon t o see pulmonary f ibrosis in t he peripheral lung adjac ent t o t he c hest w all. If suprac lav ic ular or int ernal mammary port als are also used, radiat ion c hanges may be seen in t he lung apex or paramediast inal region, respec t iv ely (229). T he f ibrosis persist s and rarely may hav e a nodular appearanc e, simulat ing pulmonary met ast asis or ly mphangit ic spread.

Breast Cancer Recurrence Def ormit ies and sc arring f rom surgery and/or post operat iv e radiat ion t herapy may make ev aluat ion f or rec urrent t umor dif f ic ult by any imaging modalit y , part ic ularly in t he f irst f ew y ears af t er surgery w hen rec urrenc e peaks (336). CT is v aluable in doc ument ing and assessing t he ext ent of rec urrent breast c arc inoma (173,292,451). Loc ally rec urrent breast c arc inoma, somet imes c linic ally unsuspec t ed or P.637 dif f ic ult t o doc ument , usually c an be demonst rat ed w it h CT w hen t he lesion exc eeds 1 c m in diamet er (451). T he presenc e of a f oc al mass on CT or MR should st rongly suggest rec urrent t umor rat her t han radiat ion- or surgery induc ed def ormit y . Rec urrent t umor may displac e t he int erc ost al musc les or ribs. When a sof t t issue densit y is seen in t he subc ut aneous t issues, c are should be t aken t o dist inguish bet w een a t rue mass and t he linear sof t t issue densit ies seen w it hin f at f ollow ing radiat ion t herapy .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1376

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 125 Rec urrent breast c anc er. Rec urrent c arc inoma inv olv ing t he lef t int ernal mammary ly mph nodes (ar r ow ) is seen f ollow ing mast ec t omy .

Rec urrenc e rat es in axillary , suprac lav ic ular, and int ernal mammary nodes (F ig. 8- 125) are on t he order of 3% or less (92); axillary and suprac lav ic ular rec urrenc e may be det ec t able by phy sic al examinat ion, w hile CT c an depic t ly mph node enlargement suspic ious f or rec urrenc e in all t hree pot ent ial sit es of nodal rec urrenc e. Loc al and regional rec urrenc e c an subsequent ly inv ade t he c hest w all, mediast inum, or st ernum (257). Bone met ast ases f rom breast c anc er may be seen on CT as ly t ic or sc lerot ic lesions in t he spine, t horac ic c age, or shoulder girdle, t hough are more f requent ly ev aluat ed by bone sc int igraphy (88). CT also may rev eal epidural met ast ases, but suspec t ed c ord c ompression is best assessed by MRI (229).

Breast Implants Breast implant s are easily depic t ed on CT as w at er- densit y st ruc t ures around w hic h c apsular c alc if ic at ion is of t en v isible, but c ont rast resolut ion is not adequat e t o ev aluat e f or implant rupt ure. MRI is t he pref erred modalit y f or t he ev aluat ion of breast implant int egrit y . T he use of mult iple, c omplement ary pulse sequenc es t hat inc lude f at , w at er, and/or silic one suppression prov ides an ac c urat e and t horough ev aluat ion f or bot h int rac apsular and ext rac apsular rupt ure (38,195). Int rac apsular rupt ure, w hic h result s in c ollapse of t he implant shell w it hin it s surrounding f ibrous c apsule, is ident if ied w hen w av y lines of t he implant shell are seen f loat ing w it hin t he implant silic one (linguine

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1377

8 - Pleura, Chest Wall, and Diaphragm

or w av y line sign); w hen t he displac ed shell produc es subc apsular lines of t he c ollapsed implant shell paralleling t he f ibrous c apsule; or w hen f oc al segment s of t he rupt ured shell inv aginat e t ow ard t he c ent er of t he implant (know n v ariously as t he t eardrop, key hole, or noose sign) (F igs. 8- 126 and 8- 127) (38,466). T hese signs of int rac apsular rupt ure should be dist inguished f rom radial f olds of t he implant shell, a normal f inding (see F ig. 8- 127). Wit h ext rac apsular rupt ure (F ig. 8- 128), mat erial hav ing t he signal c harac t erist ic s of silic one is f ound in t he ext rac apsular sof t t issues (38,78).

F igure 8- 126 Int rac apsular rupt ure: linguine sign. Sagit t al T 2- w eight ed MR image rev eals mult iple inf olded w av y lines w it hin t he high signal int ensit y of t he silic one breast implant , represent ing t he c ollapsed shell of t he rupt ured prost hesis. T he silic one is c ont ained w it hin t he f ibrous c apsule prev iously f ormed around t he implant .

AXILLA T he axilla c ont ains t he axillary art ery and v ein, and branc hes of t he brac hial plexus and ly mph nodes, and is w ell demonst rat ed on c onv ent ional c hest CT

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1378

8 - Pleura, Chest Wall, and Diaphragm examinat ion. Int erpec t oral nodes are part of t he axillary group, and int ramammary nodes are c onsidered axillary nodes f or breast c anc er st aging purposes (449). CT may det ec t enlarged axillary ly mph nodes not palpable on phy sic al examinat ion, part ic ularly in pat ient s w it h breast c anc er, ly mphoma,

upper ext remit y melanoma, or inf ec t ion (F igs. 8- 129, 8- 130, 8- 131) (203,311). Bec ause size is t he primary c rit erion f or ev aluat ing ly mph nodes by CT , t he sensit iv it y and spec if ic it y of CT are limit ed; ly mph nodes of normal size may c ont ain met ast ases, and enlarged ly mph nodes may be reac t iv e t o P.638 nonmalignant proc esses. How ev er, it is import ant t o ensure t hat t he rec onst ruc t ed f ield of v iew inc ludes t he axillary sof t t issues in pat ient s at inc reased risk of ly mph node met ast ases. Spec ial at t ent ion t o t his requirement is nec essary w hen nec k and c hest st udies are c ombined, and t he small f ield of v iew used f or t he nec k should not be ext ended t o t he t horac ic inlet . Int rav enous c ont rast mat erial c an lead t o art if ac t s t hat limit int erpret at ion of t he axilla, c hest w all, and low er part of t he nec k on t he ipsilat eral side of injec t ion (450).

F igure 8- 127 Int rac apsular rupt ure and normal radial f olds. A: Sagit t al T 2w eight ed MR image show s high signal int ensit y silic one w it hin t he implant shell and bet w een t he implant shell and t he f ibrous c apsule prev iously f ormed around t he implant . Inw ard displac ement of t he implant shell may assume

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1379

8 - Pleura, Chest Wall, and Diaphragm

dif f erent c ont ours, t o f orm t he shape of a key hole (ar r ow s) or lines paralleling t he f ibrous c apsule (ar r ow heads). B: In t he c ont ralat eral breast implant , w av y lines ext end f rom t he out er margin of t he implant t ow ard t he c ent er in a radial direc t ion. Represent ing apposit ion of t he inf olded surf ac e of t he int ac t implant shell, t hese radial f olds should not be mist aken f or t he c ollapsed shell of an int rac apsular rupt ure.

F igure 8- 128 Ext rac apsular rupt ure. Sagit t al short - t au inv ersion rec ov ery (ST IR) image rev eals high signal int ensit y silic one (ar r ow ) out side of implant c apsule. F inding c orresponded t o loc at ion of palpable abnormalit y . Not e normal radial f old (ar r ow head).

BRACHIAL PLEXUS CT c an be used t o image t he brac hial plexus region, inc luding t he subc lav ian art ery and sc alene musc les (F ig. 8- 132). How ev er, art if ac t s f rom t he adjac ent shoulder bones and f rom inf low ing c onc ent rat ed int rav enous c ont rast mat erial of t en limit anat omic det ail. MRI is t he proc edure of c hoic e f or ev aluat ing t he brac hial plexus (399,491,499,525). T he plexus is w ell demonst rat ed on direc t c oronal or sagit t al images; P.639

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1380

8 - Pleura, Chest Wall, and Diaphragm c oronally , a subst ant iv e ext ent c an be seen on a single sc an. T ransaxial images best depic t t he nerv e root s near t he spine. Sagit t al images are usef ul f or t rac ing t he nerv es in c ross sec t ion ov er t heir lengt h (see F ig. 5- 40). T he neural t runks, div isions, and c ords display low signal int ensit y relat iv e t o t he surrounding f at on T 1- and T 2- w eight ed sequenc es. T hey are easily dist inguishable f rom t he adjac ent subc lav ian art ery , w it hout int rav asc ular c ont rast administ rat ion. Lesions are generally of low signal int ensit y w it h T 1 w eight ing and of high signal int ensit y w it h T 2 w eight ing, so f at sat urat ion t ec hniques are usef ul w it h T 2- w eight ed imaging.

F igure 8- 129 Met ast at ic melanoma. Lef t axillary adenopat hy (ar r ow s), sec ondary t o a malignant melanoma prev iously resec t ed f rom t he pat ient 's bac k.

F igure 8- 130 Enlarged axillary ly mph nodes. CT image show s mult iple, rounded, homogeneous sof t t issue masses in t he axillae (ar r ow s) represent ing

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1381

8 - Pleura, Chest Wall, and Diaphragm enlarged bilat eral axillary ly mph nodes due t o non- Hodgkin ly mphoma. Subpec t oral nodes (ar r ow heads) also are part of t he axillary node group.

T here are t w o primary indic at ions f or MRI: (a) relev ant sy mpt oms, suc h as pain, parest hesia, neurologic def ic it , or musc ular at rophy ; and (b) assessment f or t he presenc e and ext ent of neoplasm in t he region (46,453,499). Radiat ion f ibrosis, primary and met ast at ic lung c anc er, and met ast at ic breast c anc er ac c ount f or almost t hree f ourt hs of nont raumat ic c ases of brac hial plexopat hy (525). Primary t umors are relat iv ely unc ommon. Benign v ariet ies inc lude neurof ibromas and sc hw annomas, and ev en more rarely lipomas, ly mphangiomas, hemangiomas, and ganglioneuromas (239,425,491,497,525). Plexif orm neurof ibromas (F ig. 8- 133) oc c ur in pat ient s w it h t y pe I neurof ibromat osis. Malignant t y pes are most ly f ibrosarc omas and malignant neurof ibromas and sc hw annomas, but also inc lude ly mphoma (F ig. 8- 134) and sy nov ial sarc oma (425,491,497,525).

F igure 8- 131 Sc rof ula. Enlarged, part ially nec rot ic , right axillary and subpec t oral ly mph nodes (LN) result ing f rom t uberc ulosis are v isible on t his CT image.

T he MRI f eat ures of benign and malignant neurogenic t umors ov erlap, as do t hose of sc hw annomas (F ig. 8- 135) and solit ary neurof ibromas (13,209). Bot h t end t o be isoint ense t o musc le on T 1- w eight ed images, hy perint ense on T 2w eight ed images, and usually show int ense c ont rast enhanc ement . One c harac t erist ic desc ribed f or benign P.640 neurogenic t umors is t he t arget sign, w hic h ref ers t o c ent ral low at t enuat ion on T 2- w eight ed images, possibly bec ause of organized c ollagen. Larger, more

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1382

8 - Pleura, Chest Wall, and Diaphragm het erogeneous masses w it h irregular margins are f indings more suggest iv e of malignanc y .

F igure 8- 132 Lipoma inv olv ing t he brac hial plexus. A: Cont rast - enhanc ed CT sc an in a 46- y ear- old w oman rev eals an asy mmet ric inc rease in f at in t he right suprac lav ic ular f ossa, splay ing t he sc alene musc les (ar r ow s). B: Slight ly more c audally , t he f at displac es t he subc lav ian v essels (w it h adjac ent brac hial plexus, not separat ely resolv ed) (ar r ow heads) slight ly ant eriorly and ext ends ext rapleurally ov er t he right lung apex (ar r ow s). Resec t ion w as perf ormed bec ause of right upper ext remit y pain and sy mpt oms of brac hial plexopat hy . Not e small lipoma of t he lef t subsc apularis musc le (open ar r ow ).

F igure 8- 133 Neurof ibromat osis inv olv ing t he brac hial plexus. A: Coronal T 1w eight ed MR image show s dif f use, nodular enlargement of t he brac hial plexus nerv es bilat erally (ar r ow s). B: Sagit t al T 2- w eight ed MR image w it h f at sat urat ion demonst rat es t he c harac t erist ic high signal int ensit y of t he neurof ibromas (ar r ow s) w it h T 2 w eight ing. High signal int ensit y is seen in t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1383

8 - Pleura, Chest Wall, and Diaphragm subc lav ian v ein (v ), relat ed t o slow blood f low . a, subc lav ian art ery ; s, ant erior sc alene musc le.

Sec ondary neoplast ic inv olv ement c an oc c ur as a result of met ast at ic breast c anc er, or by direc t ext ension of sof t t issue t umors suc h as superior sulc us lung c arc inoma (Panc oast t umor) (F ig. 8- 136), ly mphoma (see F ig. 8- 134), my eloma, desmoid t umor, c hest w all sarc oma, or dist ant primaries (491,499,525). T he lesser ac c urac y of CT c ompared w it h MRI f or ev aluat ing c hest w all inv asion in superior sulc us t umors (189) may be reduc ed by t he t ec hnologic al improv ement s of helic al sc anning and mult iplanar ref ormat t ing, but t he relat iv e adv ant ages of great er c ont rast resolut ion and reduc ed shoulder region art if ac t s w it h MRI st ill exist . Brac hial plexopat hy result ing f rom radiat ion t herapy , most c ommonly administ ered f or breast c anc er, may oc c ur sev eral mont hs t o y ears af t er t herapy has been c omplet ed, w it h a peak inc idenc e at 10 t o 20 mont hs (525). Radiat ion injury has been f ound t o be dose relat ed, and probably c annot explain brac hial plexopat hy unless doses are great er t han 6,000 c Gy (252,491). Dist inc t ion f rom t umor rec urrenc e by c linic al f indings c an be dif f ic ult . Clinic al f eat ures assoc iat ed w it h t umor inc lude sev ere pain, low er P.641 P.642 t runk (C7- 8, T - 1) inv olv ement , and Horner sy ndrome, w hile upper t runk (C5- 6) inv olv ement and ly mphedema are more assoc iat ed w it h radiat ion f ibrosis (252). Radiat ion f ibrosis may be diagnosed using MRI w it h t he appropriat e hist ory and hy point ense signal on T 1- and T 2- w eight ed images (158,499,525), alt hough t umors w it h desmoplasia may hav e similar signal c harac t erist ic s. Dif f use t hic kening of t he nerv es may be seen. Radiat ion- induc ed c hanges alone may enhanc e w it h gadolinium and may be of high signal int ensit y on T 2- w eight ed images, making dist inc t ion f rom rec urrent t umor dif f ic ult (209,385,392,499,525). A f oc al mass is suspic ious f or rec urrent t umor, and t he most reliable means of dist inc t ion f rom radiat ion f ibrosis (209,293,392,491,499). In t he absenc e of brac hial plexus abnormalit ies, MRI may rev eal ot her c auses f or sy mpt oms, suc h as my osit is, sy nov it is, or bone met ast ases (293).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1384

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 134 Ly mphoma inv olv ing t he brac hial plexus. A: Coronal T 1- w eight ed MR image demonst rat es t umor (m) of int ermediat e signal int ensit y inf ilt rat ing t he right brac hial plexus along t he superior margin of t he subc lav ian art ery (a). v , subc lav ian v ein. B: Sagit t al T 2- w eight ed MR image show s a slight inc rease in t he signal int ensit y of t he mass (m) w it h T 2 w eight ing. T he small f oc i of low signal w it hin t he mass w ere not seen w it h f low - sensit iv e gradient ec ho imaging and likely represent t he brac hial plexus nerv es. T he t umor is separat ed f rom t he subc lav ian art ery (a) by a f at plane. v , subc lav ian v ein.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1385

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 135 Brac hial plexus sc hw annoma. A homogeneous mass (ar r ow s) arises f rom t he right brac hial plexus, int ermediat e in signal on T 1- w eight ed c oronal MR image (A) and high in signal on T 2- w eight ed sagit t al MR image (B). Not e normal lef t brac hial plexus nerv es abov e t he lef t subc lav ian art ery in (A) (ar r ow heads). T ransv erse T 1- w eight ed images obt ained bef ore (C ) and af t er (D) gadolinium administ rat ion show dif f use enhanc ement of t he t umor (ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1386

8 - Pleura, Chest Wall, and Diaphragm F igure 8- 136 Panc oast t umor inv olv ing t he brac hial plexus. A: T 1- w eight ed c oronal image show s a right apic al lung mass (w hit e ar r ow ) inv ading t he rib and ext ending int o t he adjac ent sof t t issues (blac k ar r ow s). B: T 1- w eight ed sagit t al MR image rev eals t hat t he t umor ext ends int o t he suprac lav ic ular f ossa, oblit erat ing t he brac hial plexus nerv es post erior t o t he subc lav ian art ery (ar r ow ). Inv olv ement of adjac ent ribs (ar r ow heads) is seen as replac ement of t he normal high signal int ensit y of marrow , w hic h is v isible in t he more inf erior ribs.

F igure 8- 137 Parsonage- T urner sy ndrome. A: T ransv erse T 1- w eight ed image of t he lef t shoulder region in a 35- y ear- old man w it h lef t arm pain and w eakness rev eals mild at rophy of t he inf raspinat us musc le (I). B: Sagit t al T 2w eight ed image demonst rat es a mild inc rease in signal int ensit y of t he supraspinat us (S) and inf raspinat us (I) musc les. T he brac hial plexus w as normal.

T rauma inv olv ing t he proximal nerv es may result in nerv e root av ulsion and t he f ormat ion of a pseudomeningoc ele, w hic h c an be readily demonst rat ed by MRI (192,209,398,486,491). T he most c ommon c ause in adult s is mot orc y c le ac c ident s. Compared w it h c onv ent ionally used MRI t ec hniques t hat may be limit ed by mot ion art if ac t s and part ial v olume av eraging, CT my elography is more reliable f or assessing nerv e root int egrit y (13,76,491). Wit h a t hinsec t ion, ov erlapping oblique c oronal t ec hnique, how ev er, MRI has been f ound t o be c omparable w it h CT my elography in det ermining nerv e root av ulsion (110). Injury t o t he more dist al regions c an c ause hemat oma, neural edema, or neural disrupt ion w it h dist ort ion and f ormat ion of post t raumat ic neuroma (209,399).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1387

8 - Pleura, Chest Wall, and Diaphragm Brac hial neurit is, or Parsonage- T urner sy ndrome, may be c aused by a v iral inf ec t ion or it s sequelae, a c omplic at ion of a v ac c ine, ant ibiot ic , or ot her drug, or may be idiopat hic . Nerv e t hic kening, inc reased nerv e signal w it h T 2 w eight ing, and gadolinium enhanc ement of t he nerv es, or normal nerv es w it h shoulder musc le at rophy and inc reased T 2 signal of musc le result ing f rom denerv at ion and neurogenic edema (F ig. 8- 137) may be seen on MRI (13,59,192,209,385,491,499).

CARDIOTHORACIC SURGERY Preoperative Planning for Cardiac Surgery In selec t ed c ases, preoperat iv e CT has been f ound t o be usef ul f or minimizing t he risk of injury t o mediast inal st ruc t ures w hen repeat median st ernot omy is c onsidered. In pat ient s w ho hav e had int ernal mammary by pass graf t ing, or a saphenous v ein graf t displac ed ant eriorly bec ause of aneury smal dilat at ion of t he asc ending aort a, CT c an prov ide a det ailed depic t ion of t he relat ion of t he graf t t o t he st ernum (93). T he proximit y t o t he st ernum of ot her st ruc t ures at risk f or injury at reopening, suc h as t he asc ending aort a, right v ent ric le, and innominat e v ein, also c an be ev aluat ed (153). Know ledge of t hese relat ionships c an help t he surgeon in selec t ing t he best approac h t o reoperat ion. CT also may hav e a role in indiv idualizing t he surgic al approac h f or pat ient s undergoing minist ernot omy f or minimally inv asiv e c ardiac surgery (478).

F igure 8- 138 T horac oplast y . A, B: Markedly c ont rac t ed lef t hemit horax is seen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1388

8 - Pleura, Chest Wall, and Diaphragm P.643

Postsurgical Changes Thoracotomy T he expec t ed f indings f ollow ing pneumonec t omy inc lude inw ard displac ement of t he ribs and c hest w all, w it h dec reased int erc ost al spac e, sec ondary t o v olume loss (see F igs. 8- 75 and 8- 77). CT may be usef ul if it is nec essary t o assess c hanges f ollow ing c hest w all resec t ion. Sy nt het ic graf t mat erial used t o c ov er def ec t s c an be delineat ed (147), and any abnormal post operat iv e f luid c ollec t ions c an be det ec t ed. A surgic al t horac oplast y proc edure designed t o c ollapse lung in pat ient s w it h t uberc ulosis in past dec ades, or reduc e t he pleural spac e f ollow ing lung resec t ion, may inv olv e resec t ion or int ent ional f rac t ure of ribs (F ig. 8- 138).

Median Sternotomy St ernal healing af t er st ernot omy may not be apparent on CT images unt il more t han 3 mont hs af t er surgery (48). Af t er healing, segment al gaps, unev en alignment , and mild impac t ion are c ommonly seen. St ernal dehisc enc e (F ig. 8139), P.644 an inf requent but serious post operat iv e c omplic at ion of median st ernot omy , may oc c ur w it h or w it hout mediast init is (52). Risk f ac t ors f or st ernal dehisc enc e inc lude c hronic obst ruc t iv e pulmonary disease, obesit y , diabet es, int ernal mammary by pass graf t ing, prolonged by pass t ime, reoperat ion f or bleeding, prolonged post operat iv e v ent ilat ion, and of f - c ent ered st ernal inc ision or inadequat e f ixat ion (51,396,487). Alt hough dehisc enc e is usually det ec t ed c linic ally , st ernal w ire abnormalit ies, inc luding displac ement , rot at ion, and f rac t ure, are ident if iable on c hest radiographs in most c ases, and radiographic det ec t ion may somet imes prec ede t he c linic al diagnosis (51). St ernal w ire f rac t ures are relat iv ely c ommon af t er st ernot omy , and alone are usually not relat ed t o st ernal dehisc enc e. Lat eral migrat ion of st ernal w ire f ragment s c an be readily ident if ied by c hest radiography , but CT allow s prec ise loc alizat ion w hen more dist ant migrat ion oc c urs; rarely , serious c omplic at ions inc luding erosion of w ire f ragment s int o t he aort a, pulmonary art ery , bronc hus, and f at al mediast inal hemorrhage hav e been report ed

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1389

8 - Pleura, Chest Wall, and Diaphragm (187,396,437). Signs of st ernal ost eomy elit is on CT inc lude demineralizat ion, c ort ic al erosion, bone dest ruc t ion, new periost eal bone, and sc lerosis (360,487). Pat ient s may ev en present mont hs t o y ears af t er st ernot omy w it h st ernal w ound inf ec t ion and w ound disrupt ion (F ig. 8- 140) (516).

F igure 8- 139 St ernal w ound dehisc enc e. A: CT image in a 64- y ear- old man 6 w eeks af t er heart t ransplant show s an int ac t st ernot omy w ound w it h st ernot omy w ire surrounding bot h st ernot omy f ragment s. B: CT image at t he same lev el t w o w eeks lat er rev eals migrat ion of t he st ernal w ire t o t he lef t , f ragment at ion of t he right st ernot omy f ragment suspic ious f or ost eomy elit is, and a small parast ernal f luid c ollec t ion (ar r ow s) suspic ious f or an absc ess ext ending int o t he c hest w all and ant erior mediast inum. Not e small lef t pleural ef f usion.

T hough usef ul f or det ec t ing st ernal w ire abnormalit ies in dehisc enc e, c hest radiographs are of limit ed v alue in t he depic t ion of inf lammat ory c hanges and mediast inal f luid c ollec t ions f ollow ing st ernot omy . CT or MRI may prov ide inf ormat ion regarding t he c ause of mediast inal w idening seen post operat iv ely , suc h as high at t enuat ion hemorrhage (great er t han 30 HU); it c an exc lude signif ic ant ret rost ernal or mediast inal abnormalit ies, or it may help t o det ermine w het her a post st ernot omy inf ec t ion is limit ed t o t he prest ernal t issues or inv olv es t he ant erior mediast inum (163,226,397,487). F luid, edema, and inf lammat ory c hanges may be seen in t he sof t t issues adjac ent t o t he st ernum and in t he ant erior mediast inum f or sev eral w eeks and air f or up t o 1 w eek f ollow ing median st ernot omy (74,163,487,516). Loc alized mediast inal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1390

8 - Pleura, Chest Wall, and Diaphragm

f luid c ollec t ions and mediast inal air persist ing f or more t han about t w o w eeks, how ev er, are muc h more spec if ic f or a mediast inal absc ess or mediast init is (122,163,516). Pleural ef f usions of any size remaining bilat erally af t er t his t ime also hav e been assoc iat ed w it h mediast init is (329). Aspirat ion may be needed t o det ermine if a mediast inal f luid c ollec t ion is inf ec t ed (300). Mediast init is c an hav e a high mort alit y if not disc ov ered and t reat ed early (163,442,516); appropriat e management inc ludes ant ibiot ic s, drainage, and, in most c ases, surgic al dГ©bridement .

F igure 8- 140 St ernal w ound inf ec t ion, delay ed present at ion. CT image, obt ained t w o y ears af t er median st ernot omy f or aort ic dissec t ion repair in a 69- y ear- old man w it h a new palpable lump along his st ernal inc ision, show s a small low at t enuat ion c ollec t ion (ar r ow s) c ommunic at ing w it h t he spac e bet w een t he sc lerot ic , ununit ed st ernot omy f ragment s. A small absc ess w as drained and w ire f ragment remov ed. T here w ere no erosiv e c hanges of oseomy elit is.

DIAPHRAGM T he diaphragm is a musc ulot endinous st ruc t ure t hat separat es t he t horax f rom t he abdomen, and is t he primary musc le of respirat ion. Bec ause of it s t hinness and c urv ed shape, t he diaphragm is dif f ic ult t o depic t in it s ent iret y w it h CT or ot her imaging met hods. Helic al (spiral) CT w it h mult iplanar rec onst ruc t ions improv es depic t ion of t he normal and abnormal diaphragm (62). On CT , t he c rura, st ernoc ost al at t ac hment s, and port ions adjac ent t o abdominal f at are rout inely ident if iable (see F ig. 5- 69). When int rav enous c ont rast is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1391

8 - Pleura, Chest Wall, and Diaphragm administ ered, t he muc h great er enhanc ement of t he liv er, spleen, and ot her v isc era t hat may c ont ac t t he diaphragm of t en permit s dist inc t ion of t he musc ular port ions of t he diaphragm f rom t hese st ruc t ures. How ev er, t he t endonous port ion of t he diaphragm is t oo t hin t o be dist inguishable. CT may be usef ul in assessing suspec t ed def ec t s in t he st ruc t ural int egrit y of t he diaphragm, eit her c ongenit al or ac quired, w hereas peridiaphragmat ic lesions c an be loc alized and c harac t erized.

Analogous t o CT , dist inguishing t he diaphragm f rom adjac ent st ruc t ures on MR images is usually only possible w here it is in c ont ac t w it h high- signal- int ensit y abdominal or mediast inal f at . Oc c asionally , segment s are of suf f ic ient t hic kness t o be disc riminat ed f rom t he adjac ent liv er (149), and great er enhanc ement of t he adjac ent liv er f ollow ing int rav enous c ont rast enhanc ement c an improv e depic t ion of t he diaphragm (230). T he direc t mult iplanar imaging c apabilit y of MRI is adv ant ageous in assessing t he diaphragm and peridiaphragmat ic proc esses and c an be of P.645 c linic al v alue in selec t ed c ases, t hough mult iplanar CT rec onst ruc t ions also prov ide t his benef it .

NORMAL VARIANTS Diaphragmatic Crura T he diaphragmat ic c rura t aper c audally t o insert on t he ant erior aspec t s of t he f irst t hrough t hird lumbar v ert ebral bodies on t he right and f irst and sec ond lumbar v ert ebral bodies on t he lef t (168). On CT , t heir more c audal aspec t s appear as round or ov oid sof t t issue st ruc t ures t hat may seem disc ont inuous f rom t he remainder of t he post erior diaphragm and f alsely simulat e ly mphadenopat hy (69). T his appearanc e is ac c ent uat ed on images obt ained during inspirat ion w hen t he diaphragm c ont rac t s (522). Misint erpret at ion is usually easily av oided by f ollow ing t he c rura on sequent ial sc ans. Paraspinal w idening on c hest radiography result ing f rom musc ular hy pert rophy of t he c rura c an be readily dist inguished f rom ot her c auses using CT (527). Air may appear t o be present in t he ret roc rural spac e on t ransv erse images in a small perc ent age of pat ient sc ans, bec ause of part ial v olume av eraging w hen lung ext ends deep int o a post erior sulc us (460). Ident if ic at ion

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1392

8 - Pleura, Chest Wall, and Diaphragm

of pulmonary v essels on lung w indow s and c ont iguit y w it h lung in t he post erior sulc us readily explain t his appearanc e.

Diaphragmatic Pseudotumors Nodular inf oldings of t he lat eral hemidiaphragms, c reat ing diaphragmat ic pseudot umors, may be not ed on CT , most f requent ly in elderly indiv iduals, espec ially on t he lef t side (408). T his normal v ariant c an mimic perit oneal t umor implant s. If t he nodularit y is in c ont ac t w it h t he st omac h or t ransv erse c olon, ly mph node or mural masses may be simulat ed. Oc c asionally , f oc al t hic kening of t he diaphragm at it s c hest w all insert ion indent s t he liv er, simulat ing a peripheral liv er lesion (see F ig. 5- 70; F ig. 8- 143). Obt aining sc ans in a dec ubit us posit ion may resolv e a problemat ic c ase (408). In v ery musc ular indiv iduals, t he right or lef t ant erior diaphragmat ic insert ions c an simulat e ant erior diaphragmat ic ly mph nodes in t he c ardiophrenic angles (F ig. 8- 141) (21). T rac ing t hese st ruc t ures on c onsec ut iv e sc ans t o t heir c ost al at t ac hment s permit s t heir c orrec t ident if ic at ion as diaphragmat ic pseudot umors. T he lat eral arc uat e ligament s are t hic kened bands of f asc ia ov erly ing t he quadrat us lumborum musc les t o w hic h part of t he lumbar port ions of t he diaphragm are at t ac hed. T hese at t ac hment s c an on oc c asion resemble nodules or t umor implant s (F ig. 8- 142) (372,459). T hese pseudot umors are most f requent ly seen on t he right side adjac ent t o t he post erior pararenal spac e, along t he lat eral aspec t of t he lat eral arc uat e ligament , w hic h ext ends f rom t he t ransv erse proc ess of L1 t o t he middle of t he t w elf t h rib (459).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1393

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 141 Normal diaphragm. St ernal at t ac hment s of t he diaphragm (ar r ow s) in a y oung, musc ular man demonst rat ing a nodular appearanc e, simulat ing ant erior diaphragmat ic (peric ardial) ly mphadenopat hy .

DIAPHRAGMATIC HERNIAS Congenital Diaphragmatic Hernias Bochdalek Hernia A Boc hdalek hernia is a c ongenit al def ec t result ing f rom inc omplet e c losure of t he embry onic pleuroperit oneal membrane. T he lef t - sided preponderanc e is t hought t o be P.646 a result of t he earlier c losure of t he right pleuroperit oneal membrane (482) and t he prot ec t ion of right - sided def ec t s prov ided by t he liv er (136). Small

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1394

8 - Pleura, Chest Wall, and Diaphragm def ec t s may c ont ain only ret roperit oneal f at . Larger def ec t s c an c ont ain

v isc eral st ruc t ures inc luding t he st omac h, int est ines, spleen, or kidney on t he lef t , and t he liv er on t he right (371,482).

F igure 8- 142 Lat eral arc uat e ligament . T he lat eral arc uat e ligament (ar r ow heads) c an hav e a t hic kened and nodular appearanc e w here t he diaphragm at t ac hes. Not e normal lobular appearanc e of right c rus (ar r ow ).

F igure 8- 143 Boc hdalek hernia. A: Herniat ed ret roperit oneal f at (f ) ext ends upw ard int o t he low er lef t hemit horax. B: More c audally , t he lef t kidney (K) has prot ruded t hrough a def ec t in t he post erior hemidiaphragm (w hit e ar r ow s). Not e t he normal nodular appearanc e of slips of lef t hemidiaphragm (ar r ow heads) and f oc i of low at t enuat ion along t he liv er margin (blac k ar r ow s) represent ing slips of t he right hemidiaphragm indent ing t he liv er surf ac e.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1395

8 - Pleura, Chest Wall, and Diaphragm

In adult s, a Boc hdalek hernia is usually asy mpt omat ic and an inc ident al f inding (340). How ev er, sev ere sy mpt oms and serious c onsequenc es f rom inc arc erat ion or st rangulat ion of t he hernia c ont ent s c an oc c ur (352). A Boc hdalek hernia may present on c hest radiography as a sof t t issue mass bulging upw ard f rom t he post erior aspec t of a hemidiaphragm. On CT (F igs. 8143 and 8- 144), t he hernia c ont ent s usually c an be def ined w it hout dif f ic ult y and t he diaphragmat ic def ec t is usually demonst rat ed. Similar- appearing, f ar more c ommon, small f oc al diaphragmat ic def ec t s or disc ont inuit y (F ig. 8- 145), w it h or w it hout bulging or herniat ed f at or v isc era, may be seen in more t han 10% of adult s (79,144). T heir inc reasing inc idenc e w it h age, w eight gain, and emphy sema st rongly suggest s t hat t he v ast majorit y of suc h abnormalit ies demonst rat ed on CT are simply ac quired diaphragmat ic def ec t s and not t rue Boc hdalek hernias (79).

F igure 8- 144 Right Boc hdalek hernia. A: CT image rev eals herniat ed bow el and f at ext ending up int o t he post erior right low er hemit horax. B: More c audal image rev eals a def ec t in t he post erior right hemidiaphragm (ar r ow s at edges of def ec t ) t hrough w hic h t he bow el and f at hav e herniat ed.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1396

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 145 CT image in a 61- y ear- old man rev eals def ec t (ar r ow s at m ar gins of def ec t ) in t he post erior lef t hemidiaphragm and small amount of herniat ed f at . Suc h inc ident al def ec t s are most likely ac quired and age relat ed.

P.647

Morgagni Hernia Herniat ion t hrough t he f oramen of Morgagni result s f rom maldev elopment of t he embry ologic sept um t ransv ersum w it h f ailure of f usion of t he st ernal and c ost al f ibrot endinous element s of t he diaphragm (371,482), and also is of t en assoc iat ed w it h obesit y . Unlike t he Boc hdalek hernia, a hernia sac of perit oneum and pleura surrounds t he hernia c ont ent s. Morgagni hernias are most of t en right - sided, presumably bec ause lef t - sided def ec t s are c ov ered by t he heart and peric ardium. Bilat eral and assoc iat ed peric ardial def ec t s also oc c ur (152). T hese hernias usually c ome t o c linic al at t ent ion as asy mpt omat ic right c ardiophrenic angle masses det ec t ed on c hest radiographs. Sy mpt oms, w hen present , are nonspec if ic and may inc lude int ermit t ent c hest pain, t ight ness, or f ullness (352). CT readily exc ludes ot her c auses suc h as an epic ardial f at pad, peric ardial c y st or ot her mediast inal mass, or pleural or pulmonary proc esses at t he c ardiophrenic angle. Oment um, somet imes t ransv erse c olon, and rarely st omac h, small bow el, and liv er usually c omprise t he c ont ent s of a Morgagni hernia (352,482). Consequent ly , t he diagnosis c an be made on CT by ident if y ing oment al or mesent eric f at and v essels c oursing t ow ard t he f oramen of Morgagni, w it h or w it hout abdominal v isc era peripheral t o t he diaphragm in t he low er ant erior c hest (F ig. 8- 146). T here may be assoc iat ed superior displac ement of t he t ransv erse c olon (15,152). T he ac t ual

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1397

8 - Pleura, Chest Wall, and Diaphragm diaphragmat ic def ec t may be dif f ic ult t o ident if y . As w it h ot her diaphragmat ic hernias, Morgagni hernias c an bec ome quit e large and present w it h sy mpt oms relat ed t o st rangulat ion, inc arc erat ion, or obst ruc t ion (F ig. 8- 147).

Acquired Diaphragmatic Hernias Hiatal Hernia Herniat ion of t he st omac h t hrough t he esophageal hiat us is a c ommon f inding in adult s. T his ac quired abnormalit y is sec ondary t o laxit y and st ret c hing of t he phrenoesophageal ligament and w idening of t he esophageal hiat us (371,482). Obesit y and inc reased int raabdominal pressure are c ont ribut ing f ac t ors. In t y pe I, or sliding, hiat al hernias, t he phrenoesophageal ligament is w eakened and t he gast roesophageal junc t ion and a v ariable port ion of t he st omac h mov e abov e t he esophageal hiat us of t he diaphragm int o t he post erior mediast inum. Pat ient s w it h sliding hiat al hernias may be asy mpt omat ic or hav e sy mpt oms of ref lux (482). In t he muc h less c ommon t y pe II, or paraesophageal, hernias, t he ligament is rupt ured, allow ing a v ariable port ion of t he st omac h or ot her st ruc t ures t o herniat e abov e t he esophageal hiat us alongside t he gast roesophageal junc t ion, w hic h remains below t he diaphragm. Paraesophageal hernias produc e f ew sy mpt oms w hen small and are not assoc iat ed w it h heart burn and ref lux esophagit is, but may lead t o post prandial disc omf ort , subst ernal f ullness, and belc hing (501). CT sc ans rev eal ext ension of a port ion of t he proximal st omac h or ot her abdominal c ont ent s int o t he low er mediast inum (F igs. 8- 148, 8- 149, 8- 150). An abnormally w ide esophageal hiat us w it h inc reased separat ion of t he esophagus and diaphragmat ic c rura is of t en present , t he inc idenc e of w hic h inc reases w it h age (154). Mult iplanar MRI also may be used t o help def ine t he hernia c ont ent s w hen elec t iv e repair is planned (F ig. 8- 151). Very large hernias c an bec ome inc arc erat ed or undergo v olv ulus (377). Paraesophageal hernias are at part ic ular risk f or serious c omplic at ions w it hout w arning, so elec t iv e surgery is c onsidered ev en in t he absenc e of sy mpt oms. When marked asc it es oc c urs in a pat ient w it h a hiat al hernia, f luid may ext end int o t he low er post erior mediast inum, mimic king a mediast inal absc ess, nec rot ic t umor, or f oregut c y st (160). Inc omplet e dist ent ion of t he st omac h lumen w it hin t he hernia may simulat e w all t hic kening of t he gast ric f undus and raise suspic ion of neoplasm; prone posit ion sc anning t o dist end t he proximal st omac h (216) or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1398

8 - Pleura, Chest Wall, and Diaphragm f urt her ev aluat ion by endosc opy or barium f luorosc opy may be indic at ed in suspic ious c ases (F ig. 8- 152).

Traumatic Hernia T raumat ic disrupt ion of t he diaphragm c an result f rom eit her blunt (e.g., mot or v ehic le ac c ident s, f alls, and c rush injuries) or penet rat ing (e.g., knif e and bullet w ounds) injury . Diagnosis is not oriously dif f ic ult , and t raumat ic hernias of t en go undet ec t ed init ially bec ause of subt le c hanges on t he c hest radiograph, obsc uring pleuroparenc hy mal pat hology , at t ent ion t o more immediat e lif e- t hreat ening injuries, and nonsurgic al management of t horac ic or abdominal injuries (40,171,374). Posit iv e pressure v ent ilat ion may prev ent herniat ion of abdominal c ont ent s int o t he t horax unt il mec hanic al v ent ilat ion is disc ont inued, w it h a result ant delay in present at ion (75,328,345). Diagnosis may be delay ed f or day s and ev en y ears. T he lef t hemidiaphragm is more of t en af f ec t ed in blunt t rauma (171,320,374,414), w hic h usually inv olv es t he post erior c ent ral aspec t of a P.648 hemidiaphragm and ext ends radially (528), and c an c ov er more t han 10 c m in lengt h (40,217,371). Herniat ion most of t en inv olv es t he st omac h, but it c an also inv olv e t he liv er, large or small bow el, oment um, spleen, kidney , or gallbladder. In penet rat ing injuries, t he def ec t is of t en small and det ec t ed by explorat ory surgery rat her t han by imaging (443). T raumat ic hernias c an enlarge ov er t ime, presumably bec ause of t he t horac oabdominal pressure gradient , w it h risk of ev ent ual inc arc erat ion and st rangulat ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1399

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 146 Lef t Morgagni hernia. A, B: Radiographs show apparent mild elev at ion of t he lef t hemidiaphragm. C : CT image rev eals mesent eric v essels c oursing f rom ant erior t o post erior ac ross t he def ec t in t he lef t hemidiaphragm (ar r ow s at m ar gins of def ec t ) near it s ant erior st ernal at t ac hment , t ow ard herniat ed c olon and mesent eric and oment al f at . D: CT image slight ly more c audal demonst rat es a large amount of t he herniat ed f at w it hin t he t horax displac ing t he lef t hemidiaphragm (ar r ow s) ant eriorly .

T he report ed ac c urac y of CT in diagnosing t raumat ic diaphragmat ic hernias has been v ariable, w it h a report ed sensit iv it y and spec if ic it y on ret rospec t iv e st udies in t he range of 61% t o 100% and 77% t o 100%, respec t iv ely , and is bet t er f or lef t - t han right - sided rupt ures (240,270,345,353). Numerous signs help t o ident if y t raumat ic hernias (40,105,191,217,240,270,284,345,353,446,528). Cont ac t of t he upper t hird of t he liv er on t he right or t he st omac h or bow el on t he lef t w it h t he post erior ribs (dependent v isc era sign) (F igs. 8- 153 and 8- 154)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1400

8 - Pleura, Chest Wall, and Diaphragm P.649 P.650 P.651 is f requent ly present and has a high spec if ic it y . As on barium radiographic

st udies, f oc al c onst ric t ion of t he st omac h or liv er (c ollar or hourglass sign) at t he sit e of herniat ion (F ig. 8- 155) c an be demonst rat ed on CT and is also quit e spec if ic . Abrupt disc ont inuit y of t he diaphragm (F igs. 8- 154 and 8- 156) may be v isible, w it h or w it hout v isc eral herniat ion; bec ause similar small def ec t s are f requent ly seen in asy mpt omat ic persons sc anned f or indic at ions ot her t han t rauma, t his sign should be int erpret ed c aut iously . Ident if ic at ion of bow el, abdominal organs, or perit oneal f at ext ernal t o t he diaphragm indic at es int rat horac ic herniat ion (F igs. 8- 154, 8- 156, and 8- 157). Lac k of v isualizat ion of t he diaphragm (absent diaphragm sign) in an area w here it does not c ont ac t anot her organ and should normally be seen raises suspic ion of disrupt ion. Ac ut e art erial ext rav asat ion of c ont rast at t he lev el of t he diaphragm and asy mmet ric t hic kening of t he diaphragm also suggest diaphragm injury . T he presenc e of any one of t hese signs indic at es a subst ant ial c hanc e of diaphragm rupt ure (353). Apparent hemidiaphragm elev at ion alone is not spec if ic t o rupt ure, as it c an be a result of ev ent rat ion, phrenic nerv e injury , or preexist ing hemidiaphragm paraly sis. Int raperic ardial herniat ion oc c urs rarely , but may be demonst rat ed on CT (31,401).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1401

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 147 Morgagni hernia w it h ac ut e gast ric out let obst ruc t ion. A: T ransv erse CT image in a 54- y ear- old man w ho present ed w it h nausea and v omit ing demonst rat es herniat ion of t he dilat ed st omac h t o t he right of midline, post eriorly ac ross t he ant erior diaphragm (ar r ow s). B: Ref ormat t ed c oronal CT image rev eals a large right f oramen of Morgagni def ec t in t he ant erior diaphragm (ar r ow s at m ar gins of def ec t ), w it h herniat ion of t he dist al st omac h, abdominal f at , and a small port ion of nondilat ed c olon (ar r ow heads). C : Ref ormat t ed sagit t al CT image show s a t ransit ion bet w een t he dilat ed st omac h and nondilat ed duodenum (ar r ow s) c oursing ac ross t he def ec t f rom t he c hest t o t he abdomen. Hernia w as surgic ally reduc ed and t he def ec t repaired.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1402

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 148 Hiat al hernia, sliding t y pe. A: A port ion of t he st omac h (S), opac if ied w it h oral c ont rast , has passed t hrough t he diaphragm int o t he mediast inum. B: At a more c audal lev el, t here is minimal w idening of t he esophageal hiat us (ar r ow s).

F igure 8- 149 Hiat al hernia. A, B: Cephaloc audal CT images show post erior mediast inal f at c ollec t ion ext ending ac ross a mildly w idened esophageal hiat us in a paraesophageal manner.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1403

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 150 Hiat al hernia, paraesophageal t y pe. Colon and f at are herniat ed up int o t he c hest , w it h c olon herniat ed ant erior and t o t he right of t he gast roesophageal junc t ion (ar r ow ). S, st omac h.

F igure 8- 151 Paraesophageal hernia. Sagit t al T 1- w eight ed MR image rev eals a large def ec t in t he lef t hemidiaphragm (ar r ow s) and herniat ion of st omac h (S), c olon (c ), and f at int o t he c hest . MR exam w as perf ormed t o assess ext ent of diaphragmat ic def ec t and c ont ent s of t he hernia.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1404

8 - Pleura, Chest Wall, and Diaphragm

F igure 8- 152 Hiat al hernia w it h gast ric c anc er. A: CT image rev eals a hiat al hernia c ont aining a c ollapsed port ion of t he st omac h w it h a low - at t enuat ion region (ar r ow s) suspic ious f or a mass. B: Barium st udy c onf irms presenc e of a gast ric mass (ar r ow s). Adenoc arc inoma w as diagnosed on endosc opic biopsy .

F igure 8- 153 T raumat ic diaphragmat ic hernia. T rauma CT image obt ained in a 56- y ear- old man af t er a mot or v ehic le ac c ident show s elev at ion of abdominal c ont ent s int o t he lef t hemit horax and c ont ac t of t he st omac h w it h t he post erior c hest w all (dependent v isc era sign).

Small def ec t s f rom penet rat ing t rauma are dif f ic ult t o det ec t in t he absenc e of herniat ion, but an injury t rac t in line w it h t he diaphragm or c ont iguous organ injury on eit her side of t he diaphragm (e.g., liv er and lung) signif ies t hat a diaphragm injury is likely . T he most f requent injuries assoc iat ed w it h diaphragm rupt ure in mot or v ehic le t rauma inc lude liv er or spleen injury , rib and pelv ic f rac t ures (Berquist 's t riad: rib f rac t ures, spine/pelv ic f rac t ures, and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1405

8 - Pleura, Chest Wall, and Diaphragm diaphragmat ic rupt ure), and pulmonary c ont usion (24,400). Ot her c harac t erist ic s of mot or v ehic le c ollisions assoc iat ed w it h diaphragm rupt ure inc lude lef t lat eral c ollisions w it h int rusion of more t han 30 c m and great er kinet ic energy t ransf er (c hange in v eloc it y more t han 50 kilomet ers per hour) (400). Short - t erm out c ome w it h t raumat ic P.652

herniat ion of t he diaphragm depends on t he assoc iat ed injuries rat her t han t he diaphragm rupt ure (319,414).

F igure 8- 154 T raumat ic rupt ure of t he diaphragm. A: T rauma CT image obt ained f ollow ing a mot or v ehic le c ollision demonst rat es herniat ion of t he st omac h (S) and c olon (C) int o t he lef t hemit horax, w it h post erior displac ement of t he st omac h and adjac ent f luid or blood (dependent v isc era sign). B: More c audal image rev eals disc ont inuit y of t he diaphragm (ar r ow s at m ar gins of def ec t ) at t he sit e of rupt ure, w it h herniat ed bow el seen at t his lev el peripheral t o t he diaphragm. Small lef t pleural ef f usion is present . C : Sagit t al rec onst ruc t ion f rom a t rauma CT in anot her pat ient show s f ree edge of t he lef t hemidiaphragm at t he sit e of rupt ure (ar r ow ), w it h herniat ion of t he c ont rast - f illed st omac h int o t he c hest and a large pleural ef f usion.

Coronal and sagit t al ref ormat t ing of v olumet ric CT image dat a may be helpf ul in c ert ain c ases (218,233,443,492), t hough may not alw ay s be def init iv e or prov ide addit ional inf ormat ion (240), and may be misleading (270). In some c ases, mushrooming of t he liv er t hrough a diaphragm t ear t o produc e t he c ollar sign is apparent only on ref ormat t ed images (240,420), and c ould be obsc ured by pleural ef f usions or parenc hy mal lung disease on c hest radiographs. Direc t c oronal or sagit t al imaging w it h MRI also may be helpf ul in diagnosing t raumat ic diaphragmat ic hernias, w hic h may be more readily

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1406

8 - Pleura, Chest Wall, and Diaphragm rec ognized in t hese planes. Applic at ion is generally limit ed t o nonc rit ic ally ill and hemody namic ally st able pat ient s in w hom a delay ed diagnosis is sought (33,57,171,217,447).

SUPERIOR DIAPHRAGMATIC LYMPH NODES Sev eral ly mph node groups lie along t he superior, c ent ral aspec t of t he diaphragm. T he ly mph nodes along t he ant erior port ion drain t he diaphragm, ant erior mediast inum, and ant erosuperior liv er (412). T hese ant er ior diaphr agm at ic (c ar diophr enic angle, per ic ar dial, par ac ar diac ) nodes reside post erior t o t he xiphoid and behind t he sev ent h ribs and c ost al c art ilages in t he c ardiophrenic angles (21,288). Up t o t w o ly mph nodes, nearly alw ay s less t han 5 mm in diamet er, normally may be v isible on CT sc ans (21). CT is muc h more sensit iv e in det ec t ing ant erior diaphragmat ic ly mphadenopat hy t han is c hest radiography . Unilat eral or bilat eral ant erior diaphragmat ic ly mphadenopat hy (F ig. 8- 158) is most of t en assoc iat ed w it h ly mphoma or lung, breast , or c olon c anc er (21,288,477). In c ases of ly mphoma, ident if ic at ion of lat eral ant erior diaphragmat ic ly mphadenopat hy may alt er radiat ion port planning (477), and f ailure t o inc lude t hese nodes might lead t o t reat ment f ailure (288). When t hese ly mph nodes are enlarged, ly mphadenopat hy in ot her loc at ions or liv er met ast ases usually are present (21). Cardiophrenic angle port osy st emic v aric es may oc c ur in pat ient s w it h port al hy pert ension, part ic ularly on t he right (505). Delay ed sc ans may be nec essary t o demonst rat e enhanc ement of t hese st ruc t ures and av oid t he misdiagnosis of ant erior diaphragmat ic ly mphadenopat hy . Ot her masses t hat c an be relat ed t o t he ant erior diaphragm inc lude peric ardial f at and peric ardial c y st s, w hic h c an be dist inguished f rom ot her c ardiophrenic angle masses on t he basis of t heir c harac t erist ic CT at t enuat ion v alues, and Morgagni hernia. Middle diaphr agm at ic nodes, usually not v isible, may be seen abov e t he diaphragm medial t o t he hemidiaphragm dome w hen enlarged, part ic ularly on t he right adjac ent t o P.653 t he inf erior v ena c av a (see F ig. 8- 158). Post er ior diaphr agm at ic ly mph nodes are loc at ed in t he inf erior aspec t of t he post erior mediast inum, in t he ret roc rural spac e. T he ret roc rural spac e normally c ont ains t he aort a, azy gos v ein, t horac ic duc t , nerv es, and ly mph nodes less t han 6 mm in short axis diamet er t hat drain t he post erior mediast inum, diaphragm, and lumbar region (70,454). Ret roc rural ly mphadenopat hy (F ig. 8- 159) is suggest ed w hen

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1407

8 - Pleura, Chest Wall, and Diaphragm disc ret e sof t t issue masses larger t han 6 mm are present and may f requent ly be ac c ompanied by upper abdominal paraaort ic ly mphadenopat hy (70). T he most c ommon malignant proc ess t o inv olv e t he ret roc rural ly mph nodes is ly mphoma, but bot h malignant and benign diseases c an c ause enlargement (115). High- at t enuat ion ret roc rural ly mph nodes c an be seen in t he rare pat ient w ho has prev iously undergone ly mphangiography , and rarely in met ast at ic adenoc arc inoma.

F igure 8- 155 Delay ed inc ident al det ec t ion of t raumat ic diaphragmat ic hernia. A: Chest radiograph in a man being ev aluat ed f or elec t iv e surgery rev eals a sof t t issue mass projec t ing int o t he right lung base. T he pat ient had a remot e hist ory of a mot or v ehic le c ollision. Coronal B: and sagit t al C : images show

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1408

8 - Pleura, Chest Wall, and Diaphragm mushrooming of a port ion of t he liv er int o t he c hest t hrough a c onst ric t ing diaphragm def ec t (c ollar sign). A, ant erior.

Azy gos v ein enlargement (F ig. 8- 160) c an oc c ur w it h anomalous int errupt ion, t hrombosis, or obst ruc t ion of t he inf erior v ena c av a and should not be mist aken f or ret roc rural ly mphadenopat hy . T hat t he suspec t ed mass is a t ubular st ruc t ure c ont inuous c ephalad w it h t he azy gos v ein, w hic h enhanc es w it h int rav enous c ont rast administ rat ion, c onf irms t he diagnosis. Ot her ret roc rural v asc ular masses, suc h as esophageal v aric es or hemorrhage f rom aort ic aneury sm rupt ure (454), usually are easily det ec t ed w it h CT . Ext ension of disease proc esses f rom t he adjac ent spine, suc h as malignanc y , inf ec t ion, or f rac t ure w it h hemat oma, c an produc e an abnormalit y on CT in t he ret roc rural area.

F igure 8- 156 Delay ed sy mpt omat ic present at ion of inc arc erat ed t raumat ic diaphragmat ic hernia. A: T ransv erse CT image in a 43- y ear- old man w ho sust ained an ant erior t horac ic st ab w ound y ears prev iously show s a dilat ed

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1409

8 - Pleura, Chest Wall, and Diaphragm loop of c olon herniat ed int o t he lef t hemit horax. B: More c audal image show s sit e of herniat ion t hrough t he diaphragmat ic def ec t (ar r ow s at m ar gins of def ec t ) and a small amount of reac t iv e f luid (ar r ow head). C : Ref ormat t ed c oronal image show s herniat ed, dilat ed loop of c olon abov e t orn f ree edge of t he diaphragm (ar r ow ), w it h obst ruc t iv e dilat at ion of t he asc ending (A) and t ransv erse (T ) c olon. T he pat ient present ed ac ut ely w it h abdominal pain, nausea, and v omit ing. T he inc arc erat ed, obst ruc t ed c olon w as surgic ally reduc ed and an ant erior diaphragmat ic def ec t w as repaired.

F igure 8- 157 Delay ed inc ident al det ec t ion of t raumat ic diaphragmat ic hernia. T ransv erse (A) and rec onst ruc t ed c oronal (B) CT images in a 35- y ear- old w oman being ev aluat ed f or pulmonary embolism rev eal herniat ion of mesent ery and mult iple bow el loops int o t he right hemit horax abov e t he liv er. Pat ient report ed a hist ory of abdominal t rauma many y ears prior.

F igure 8- 158 Superior diaphragmat ic ly mph nodes. A: Mildly enlarged ant erior (ar r ow s) and middle (ar r ow shead) diaphragmat ic ly mph nodes in a pat ient

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1410

8 - Pleura, Chest Wall, and Diaphragm

w it h nodal plasmac y t oma. A small right pleural ef f usion is present . B: Bilat eral axillary (ar r ow s) and right int ernal mammary (ar r ow head) ly mph nodes are also enlarged.

F igure 8- 159 Post erior diaphragmat ic (ret roc rural) ly mph nodes. Mildly enlarged ret roc rural ly mph nodes (ar r ow s) in a pat ient w it h non- Hodgkin ly mphoma. Not e normal nodularit y of diaphragmat ic c rura (ar r ow heads).

F igure 8- 160 Azy gos c ont inuat ion of t he inf erior v ena c av a. A: Slight ly enhanc ing azy gos (a) and hemiazy gos v ein (h) are seen in t he ret roc rural spac e adjac ent t o t he aort a (Ao). At t his lev el, t he appearanc e is similar t o

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1411

8 - Pleura, Chest Wall, and Diaphragm t hat of t he ret roc rural ly mphadenopat hy in F ig. 8- 159. B: More c ephalad, t hese c ont inue as t ubular st ruc t ures, and t he hemiazy gos v ein (h) c rosses post erior t o t he aort a t o join t he azy gos v ein (a).

P.654 P.655 P.656

DIAPHRAGM TUMORS Primary t umors of t he diaphragm are ext remely rare (362,438). T he f requenc y of benign t umors is equal t o or great er t han t hat of malignant t umors, and t he right and lef t sides are equally af f ec t ed (519). Benign t umors report ed inc lude mesot helial, t erat oid, or bronc hogenic c y st s, lipomas, hemangiomas, neurogenic t umors, f ibromas, and benign t umors of musc le (210,231,254,362,413,438). Small f at - at t enuat ion masses may be not ed on CT w it hin t he diaphragm musc le c onsist ent w it h lipomas, t oo small f or c linic al or radiographic det ec t ion. Suc h lesions may simply represent age- assoc iat ed lipomat ous diaphragmat ic def ec t s (79). Most malignant primary t umors are sarc omas of f ibrous or musc ular origin (141,362,391). T he appearanc e of sof t t issue t umors generally is nonspec if ic , and bec ause t he diaphragm is a t hin st ruc t ure of sof t t issue at t enuat ion, c onf ident CT ident if ic at ion of t he diaphragmat ic origin of a mass dist inc t f rom t he adjac ent liv er or pleura of t en is dif f ic ult or impossible (210,391,413). T horac ic or abdominal t umors may sec ondarily inv olv e t he diaphragm by direc t ext ension. Suc h t umors inc lude bronc hogenic c arc inoma, mesot helioma and ot her primary or sec ondary pleural or c hest w all malignanc ies, hepat ic malignanc ies, perit oneal c arc inomat osis, and t umors of t he st omac h, kidney , adrenal gland, c olon, ov ary , or ret roperit oneum, as w ell as ly mphoma (482). Diaphragmat ic implant s adjac ent t o t he liv er c an simulat e int rahepat ic lesions. Empy ema nec essit at is t hrough t he diaphragm in c hronic t uberc ulous empy ema also has been report ed, w it h f ist ula demonst rat ed by MRI (428). How ev er, w hen t horac ic or abdominal masses abut t he diaphragm w it hout t rav ersing it , def init iv e diagnosis of inv asion c annot be made. T here hav e been rare report s of endomet riosis inv olv ing t he diaphragm (347).

DIAPHRAGM MOTION

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1412

8 - Pleura, Chest Wall, and Diaphragm Paraly sis of a hemidiaphragm may be suspec t ed on CT sc ans w hen not able

hemidiaphragm elev at ion is seen. Lac k of breat hing mot ion art if ac t on one side in pat ient s unable t o suspend respirat ion or during f orc ed exhalat ion also might be suggest iv e (183). Using f ast , dy namic MRI t ec hniques, repeat ed sc ans c an be obt ained in a single plane and display ed in c ine f ormat t o v iew diaphragm mot ion, w it hout ionizing radiat ion. T his has been used primarily as an inv est igat iv e t ool t o ev aluat e and quant if y normal breat hing mec hanic s (91,148,220,384,480) and impairment s in pat ient s w it h obst ruc t iv e lung disease (150,219,221,475,494) and sc oliosis (253). Alt hough dy namic MRI c an show hemidiaphragm paraly sis (151), f luorosc opy remains t he examinat ion of c hoic e f or t his indic at ion, being f ar simpler, f ast er, and muc h less c ost ly .

REFERENCES 1. Aberle DR, Gamsu G, Ray CS. High- resolut ion CT of benign asbest os- relat ed diseases: c linic al and radiographic c orrelat ion. AJR Am J Roent genol 1988;151:883–891. 2. Aberle DR, Gamsu G, Ray CS, et al. Asbest os- relat ed pleural and parenc hy mal f ibrosis: det ec t ion w it h high- resolut ion CT . Radiology 1988;166:729–734 3. Adams RF , Gray W, Dav ies RJ, et al. Perc ut aneous image- guided c ut t ing needle biopsy of t he pleura in t he diagnosis of malignant mesot helioma. Chest 2001;120:1798–1802. 4. Adler BD, Padley SPG, Muller NL. T uberc ulosis of t he c hest w all: CT f indings. J Comput Assist T omogr 1993;17:271–273. 5. Aisner J. Current approac h t o malignant mesot helioma of t he pleura. Chest 1995;107(6 suppl):332s–344s. 6. Akashi- T anaka S, F ukut omi T , Sat o N, et al. T he role of c omput ed t omography in t he selec t ion of breast c anc er t reat ment . Breast Canc er 2003;10:198–203. 7. Akashi- T anaka S, F ukut omi T , Wat anabe T , et al. Ac c urac y of c ont rast enhanc ed c omput ed t omography in t he predic t ion of residual breast c anc er af t er neoadjuv ant c hemot herapy . Int J Canc er 2001;96:66–73. 8. Albelda SM, Epst ein DM, Gef t er WB, et al. Pleural t hic kening: it s signif ic anc e and relat ionship t o asbest os dust exposure. Am Rev Respir Dis 1982;126:621–624. 9. Alexander C. Diaphragm mov ement s and t he diagnosis of diaphragmat ic paraly sis. Clin Radiol 1966;17:79–83.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1413

8 - Pleura, Chest Wall, and Diaphragm 10. Alexander E, Clark RA, Colley DP, et al. CT of malignant pleural mesot helioma. AJR Am J Roent genol 1981;137:287–291.

11. Alexander ES, Prot o AV, Clark RA. CT dif f erent iat ion of subphrenic absc ess and pleural ef f usion. AJR Am J Roent genol 1983; 140:47–51. 12. Alexander JC Jr, Wolf e WG. Lung absc ess and empy ema of t he t horax. Surg Clin Nort h Am 1980;60:835–849. 13. Amrami KK, Port JD. Imaging t he brac hial plexus. Hand Clin 2005;21:25–37. 14. Anderson DJ, Glazer HS, Molina PL, et al. Subpleural t horac ic f at as def ined w it h CT of t he c hest . Radiology 1988;169 (P Supplement ):254. 15. Ant hes T B, T hoongsuw an N, Karmy - Jones R. Morgagni hernia: CT f indings. Curr Probl Diagn Radiol 2003;32:135–136. 16. Aoki J, Moser RP Jr, Kransdorf MJ. Chondrosarc oma of t he st ernum: CT f eat ures. J Comput Assist T omogr 1989;13:806–810. 17. Aoki J, T anikaw a H, Ishii K, et al. MR f indings indic at iv e of hemosiderin in giant - c ell t umor of bone: f requenc y , c ause, and diagnost ic signif ic anc e. AJR Am J Roent genol 1996;166: 145–148. 18. Aquino SL, Chen MY , Kuo WT , et al. T he CT appearanc e of pleural and ext rapleural disease in ly mphoma. Clin Radiol 1999;54: 647–650. 19. Aquino SL, Webb WR, Gushiken BJ. Pleural exudat es and t ransudat es: diagnosis w it h c ont rast - enhanc ed CT . Radiology 1994;192: 803–808. 20. Ariy urek OM, Gulsun M, Demirkazik F B. Ac c essory f issures of t he lung: ev aluat ion by high- resolut ion c omput ed t omography . Eur Radiol 2001;11:2449–2453. 21. Aronberg DJ, Pet erson RR, Glazer HS, et al. Superior diaphragmat ic ly mph nodes: CT assessment . J Comput Assist T omogr 1986; 10:937–941. 22. Arslanian A, Oliaro A, Donat i G, et al. Post t raumat ic pulmonary hernia. J T horac Cardiov asc Surg 2001;122:619–621. 23. Aslam M, Rajesh A, Ent w isle J, et al. Pic t orial rev iew : MRI of t he st ernum and st ernoc lav ic ular joint s. Br J Radiol 2002; 75:627–634. 24. At hanassiadi K, Kalav rouziot is G, At hanassiou M, et al. Blunt diaphragmat ic rupt ure. Eur J Cardiot horac Surg 1999;15:469–474. 25. Au V, Leung AN. Radiologic manif est at ions of ly mphoma in t he t horax. AJR Am J Roent genol 1997;168:93–98. 26. Aust in JH. T he lef t minor f issure. Radiology 1986;161:433–436. 27. Aziz A, Ashizaw a K, Nagaoki K, et al. High resolut ion CT anat omy of t he pulmonary f issures. J T horac Imaging 2004;19: 186–191.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1414

8 - Pleura, Chest Wall, and Diaphragm P.657 28. Baber CE, Hedlund LW, Oddson T A, et al. Dif f erent iat ing empy emas and

peripheral pulmonary absc esses: t he v alue of c omput ed t omography . Radiology 1980;135:755–758. 29. Baker EL, Greene R. Inc rement al v alue of oblique c hest radiographs in t he diagnosis of asbest os- induc ed pleural disease. Am J Ind Med 1982;3:17–22. 30. Baldt MM, Bankier AA, Germann PS, et al. Complic at ions af t er emergenc y t ube t horac ost omy : assessment w it h CT . Radiology 1995;195:539–543. 31. Barker JA, Gav ant ML, Hughes CB. Post t raumat ic int raperic ardial diaphragmat ic hernia. AJR Am J Roent genol 1997;169:315–316. 32. Bart let t JG, F inegold SM. Anaerobic inf ec t ions of t he lung and pleural spac e. Am Rev Respir Dis 1974;110:56–77. 33. Basso SM, Carat ozzolo E, Massani M, et al. Noc t urnal dy spnea in a y oung adult male pat ient : a t y pic al c ase of an unrec ognized t raumat ic rupt ure of t he diaphragm. J T rauma 2004;56:720. 34. Bat ra P, Brow n K, Hay ashi K, et al. Rounded at elec t asis. J T horac Imaging 1996;11:187–197. 35. Belf ar HL, Radec ki PD, F riedman AC, et al. Panc reat it is present ing as pleural ef f usions: c omput ed t omography demonst rat ion of pleural spac e ext ension of panc reat it is exudat e. J Comput T omogr 1987;11:184–187. 36. Belt ran J, Simon DC, Lev y M, et al. Aneury smal bone c y st s: MR imaging at 1.5 T . Radiology 1986;158:689–690. 37. Berg WA, Gut ierrez L, NessAiv er MS, et al. Diagnost ic ac c urac y of mammography , c linic al examinat ion, US, and MR imaging in preoperat iv e assessment of breast c anc er. Radiology 2004;233: 830–849. 38. Berg WA, Nguy en T K, Middlet on MS, et al. MR imaging of ext rac apsular silic one f rom breast implant s: diagnost ic pit f alls. AJR Am J Roent genol 2002;178:465–472. 39. Bergin CJ, Healy MV, Zinc one GE, et al. MR ev aluat ion of c hest w all inv olv ement in malignant ly mphoma. J Comput Assist T omogr 1990;14:928–932. 40. Bergin D, Ennis R, Keogh C, et al. T he “ dependent v isc era” sign in CT diagnosis of blunt t raumat ic diaphragmat ic rupt ure. AJR Am J Roent genol 2001;177:1137–1140. 41. Berkmen T , Berkmen Y M, Aust in JH. Ac c essory f issures of t he upper lobe of t he lef t lung: CT and plain f ilm appearanc e. AJR Am J Roent genol 1994;162:1287–1293.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1415

8 - Pleura, Chest Wall, and Diaphragm 42. Bert hot y DP, Shulman HS, Miller HAB. Elast of ibroma: c hest w all pseudot umor. Radiology 1986;160:341–342. 43. Bert ino RE, Wesbey GE, Johnson RJ. Horner sy ndrome oc c urring as a c omplic at ion of c hest t ube plac ement . Radiology 1987;164:745. 44. Bhalla M, Mc Cauley DI, Golimbu C, et al. Count ing ribs on c hest CT . J Comput Assist T omogr 1990;14:590–594. 45. Bhat t GM, Aust in HM. CT demonst rat ion of empy ema nec essit at is. J Comput Assist T omogr 1985;9:1108–1109. 46. Bilbey JH, Lammond RG, Mat t rey RF . MR imaging of disorders of t he brac hial plexus. J Magn Reson Imaging 1994;4:13–18. 47. Biondet t i PR, F iore D, Sart ori F , et al. Ev aluat ion of post - pneumonec t omy spac e by c omput ed t omography . J Comput Assist T omogr 1982;6:238–242. 48. Bit kov er CY , Cederlund K, Aberg B, et al. Comput ed t omography of t he st ernum and mediast inum af t er median st ernot omy . Ann T horac Surg 1999;68:858–863. 49. Blac k LF . Pleural ef f usions. May o Clinic Proc 1991;56:201–202. 50. Bluemke DA, Gat sonis CA, Chen MH, et al. Magnet ic resonanc e imaging of t he breast prior t o biopsy . JAMA 2004;292: 2735–2742. 51. Boiselle PM, Mansilla AV, F isher MS, et al. Wandering w ires: f requenc y of st ernal w ire abnormalit ies in pat ient s w it h st ernal dehisc enc e. AJR Am J Roent genol 1999;173:777–780. 52. Boiselle PM, Mansilla AV, Whit e CS, et al. St ernal dehisc enc e in pat ient s w it h and w it hout mediast init is. J T horac Imaging 2001; 16:106–110. 53. Bonomo L, F eragalli B, Sac c o R, et al. Malignant pleural disease. Eur J Radiol 2000;34:98–118. 54. Boone JM, Nelson T R, Lindf ors KK, et al. Dedic at ed breast CT : radiat ion dose and image qualit y ev aluat ion. Radiology 2001; 221:657–667. 55. Bourgouin P, Cousineau G, Lemire P, et al. Comput ed t omography used t o exc lude pneumot horax in bullous lung disease. J Can Assoc Radiol 1985;36:341–342. 56. Bout in C, Rey F , Viallat JR. Prev ent ion of malignant seeding af t er inv asiv e

diagnost ic proc edures in pat ient s w it h pleural mesot helioma. A randomized t rial of loc al radiot herapy . Chest 1995;108: 754–758. 57. Bow ley DM, Grac e KL, Hughes PM, et al. Rupt ure of t he right hemidiaphragm w it h liv er herniat ion. J T rauma 2002;52:411.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1416

8 - Pleura, Chest Wall, and Diaphragm 58. Bradley F M, Hoov er HC Jr, Hulka CA, et al. T he st ernalis musc le: an unusual normal f inding seen on mammography . AJR Am J Roent genol 1996;166:33–36. 59. Bredella MA, T irman PF , F rit z RC, et al. Denerv at ion sy ndromes of t he

shoulder girdle: MR imaging w it h elec t rophy siologic c orrelat ion. Skelet al Radiol 1999;28:567–572. 60. Brenner J, Sordillo PP, Magill GB, et al. Malignant mesot helioma of t he pleura: rev iew of 123 pat ient s. Canc er 1982;49: 2431–2435. 61. Bressler EL, F ranc is IR, Glazer GM, et al. Bolus c ont rast medium enhanc ement f or dist inguishing pleural f rom parenc hy mal lung disease: CT f eat ures. J Comput Assist T omogr 1987;11: 436–440. 62. Brink JA, Heiken JP, Semenkov ic h J, et al. Abnormalit ies of t he diaphragm and adjac ent st ruc t ures: f indings on mult iplanar spiral CT sc ans. AJR Am J Roent genol 1994;163:307–310. 63. Briselli M, Mark EJ, Dic kersin GR. Solit ary f ibrous t umors of t he pleura: eight new c ases and rev iew of 360 c ases in t he lit erat ure. Canc er 1981;47:2678–2689. 64. Broaddus C, St aub NC. Pleural liquid and prot ein t urnov er in healt h disease. Semin Respir Crit Care Med 1987;9:7–12. 65. Broc k MV, Heit miller RF . Spont aneous ant erior t horac ic lung hernias. J T horac Cardiov asc Surg 2000;119:1046–1047. 66. By dder GM, Kreel L. Pleural c alc if ic at ion in panc reat it is demonst rat ed by c omput ed t omography . J Comput Assist T omogr 1981; 5:161–163. 67. Cac eres J, Mat a JM, Alegret X, et al. Inc reased densit y of t he azy gos lobe on f ront al c hest radiographs simulat ing disease: CT f indings in sev en pat ient s. AJR Am J Roent genol 1993;160:245–248. 68. Cac eres J, Mat a JM, Andreu J. T he azy gos lobe: normal v ariant s t hat may simulat e disease. Eur J Radiol 1998;27:15–20. 69. Callen PW, F illy RA, Korobkin M. Comput ed t omographic ev aluat ion of t he diaphragmat ic c rura. Radiology 1978;126: 413–416. 70. Callen PW, Korobkin M, Isherw ood I. Comput ed t omographic ev aluat ion of t he ret roc rural prev ert ebral spac e. AJR Am J Roent genol 1977;129:907–910. 71. Cameron EW, Mirv is SE, Shanmuganat han K, et al. Comput ed t omography of malposit ioned t horac ost omy drains: a pic t orial essay . Clin Radiol 1997;52:187–193.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1417

8 - Pleura, Chest Wall, and Diaphragm 72. Cardillo G, F ac c iolo F , Cav azzana AO, et al. Loc alized (solit ary ) f ibrous t umors of t he pleura: an analy sis of 55 pat ient s. Ann T horac Surg 2000;70:1808–1812. 73. Carlsen SE, Bergin CJ, Hoppe RT . MR imaging t o det ec t c hest w all and pleural inv olv ement in pat ient s w it h ly mphoma: ef f ec t on radiat ion t herapy planning. AJR Am J Roent genol 1993;160: 1191–1195.

74. Cart er AR, Sost man HD, Curt is AM, et al. T horac ic alt erat ions af t er c ardiac surgery . AJR Am J Roent genol 1983;140:475–481. 75. Cart er Y M, Karmy - Jones RC, St ern EJ. Delay ed rec ognit ion of diaphragmat ic rupt ure in a pat ient rec eiv ing mec hanic al v ent ilat ion. AJR Am J Roent genol 2001;176:428. 76. Carv alho GA, Nikkhah G, Mat t hies C, et al. Diagnosis of root av ulsions in t raumat ic brac hial plexus injuries: v alue of c omput erized t omography my elography and magnet ic resonanc e imaging. J Neurosurg 1997;86:69–76. 77. Casillas J, Sais GJ, Grev e JL, et al. Imaging of int ra- and ext raabdominal desmoid t umors. Radiographic s 1991;11:959–968. 78. Caskey CI, Berg WA, Hamper UM, et al. Imaging spec t rum of ext rac apsular silic one: c orrelat ion of US, MR imaging, mammographic , and hist opat hologic f indings. Radiographic s 1999;19 [Spec No]:s39–s51; quiz s261–s262. 79. Caskey CI, Zerhouni EA, F ishman EK, et al. Aging of t he diaphragm: a CT st udy . Radiology 1989;171:385–389. P.658 80. Chailleux E, Dabouis G, Pioc he D, et al. Prognost ic f ac t ors in dif f use malignant pleural mesot helioma. A st udy of 167 pat ient s. Chest 1988;93:159–162. 81. Chang CHJ, Nesbit DE, F isher DR, et al. Comput ed t omographic mammography using a c onv ent ional body sc anner. AJR Am J Roent genol 1982;138:553–558. 82. Cho CS, Blank N, Cast ellino RA. Comput erized t omography ev aluat ion of c hest w all inv olv ement in ly mphoma. Canc er 1985; 55:1892–1894. 83. Choe DH, Lee JH, Lee BH, et al. Post pneumonec t omy empy ema. CT f indings in six pat ient s. Clin Im aging 2001;25:28–31. 84. Cihangiroglu M, Lin BH, Dac hman AH. Collat eral pat hw ay s in superior v ena c av al obst ruc t ion as seen on CT . J Com put Assist T om ogr 2001;25:1–8. 85. Cohen AM, Crass JR, Chung- Park M, et al. Rounded at elec t asis and f ibrot ic pleural disease: t he pat hologic c ont inuum. J T hor ac Im aging 1993;8:309–312.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1418

8 - Pleura, Chest Wall, and Diaphragm 86. Cohen LM, Sc hw art z AM, Roc kof f SD. Benign sc hw annomas: pat hologic basis f or CT inhomogeneit ies. AJR Am J Roent genol 1986;147:141–143.

87. Colw ell AS, D'Cunha J, Vargas SO, et al. Sy nov ial sarc oma of t he pleura: a c linic al and pat hologic st udy of t hree c ases. J T hor ac Car diov asc Sur g 2002;124:828–832. 88. Connolly JE Jr, Erasmus JJ, Pat z EF Jr. T horac ic manif est at ions of breast c arc inoma: met ast at ic disease and c omplic at ions of t reat ment . Clin Radiol 1999;54:487–494. 89. Cooper C, Moss AA, Buy JN, et al. CT appearanc e of t he normal inf erior pulmonary ligament . AJR Am J Roent genol 1983;141: 237–240. 90. Copley SJ, Wells AU, Rubens MB, et al. F unc t ional c onsequenc es of pleural disease ev aluat ed w it h c hest radiography and CT . Radiology 2001;220:237–243. 91. Craighero S, Promay on E, Bac onnier P, et al. Dy namic ec ho- planar MR imaging of t he diaphragm f or a 3D dy namic analy sis. Eur Radiol 2005;15:742–748. 92. Cranenbroek S, v an der Sangen MJ, Kuijt GP, et al. Diagnosis, t reat ment and prognosis of int ernal mammary ly mph node rec urrenc e in breast c anc er pat ient s. Br east Canc er Res T r eat 2005; 89:271–275. 93. Cremer J, T eebken OE, Simon A, et al. T horac ic c omput ed t omography prior t o redo c oronary surgery . Eur J Car diot hor ac Sur g 1998;13:650–654. 94. Crot t y EJ, Mc Adams HP, Erasmus JJ, et al. Epit helioid hemangioendot helioma of t he pleura: c linic al and radiologic f eat ures. AJR Am J Roent genol 2000;175:1545–1549. 95. Daneman A, Manc er K, Sonley M. CT appearanc e of t hic kened nerv es in neurof ibromat osis. AJR Am J Roent genol 1983;141: 899–900. 96. Dav is SD, Hensc hke CI, Y ankelev it z DF , et al. MR imaging of pleural ef f usions. J Com put Assist T om ogr 1990;14:192–198. 97. Dav is SD, Y u LS, Hent el KD. Obliquely orient ed superior ac c essory f issure of t he low er lobe of t he lung: CT ev aluat ion of t he normal appearanc e and ef f ec t on t he dist ribut ion of parenc hy mal and pleural opac it ies. Radiology 2000;216:97–106. 98. de Campos JR, Vargas F S, de Campos Werebe E, et al. T horac osc opy t alc poudrage: a 15- y ear experienc e. Chest 2001;119: 801–806. 99. de Gaut ard R, Dussault RG, Chahlaoui J, et al. Cont ribut ion of CT in t horac ic bony lesions. J Can Assoc Radiol 1981;32:39–41.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1419

8 - Pleura, Chest Wall, and Diaphragm 100. de Perrot M, Kurt AM, Robert JH, et al. Clinic al behav ior of solit ary f ibrous t umors of t he pleura. Ann T hor ac Sur g 1999;67: 1456–1459.

101. DeCamp MM Jr, Ment zer SJ, Sw anson SJ, et al. Malignant ef f usiv e disease of t he pleura and peric ardium. Chest 1997;112(4 suppl): 291s–295s. 102. Dedric k CG, Mc Loud T C, Shepard JA, et al. Comput ed t omography of loc alized pleural mesot helioma. AJR Am J Roent genol 1985;144:275–280. 103. Delorme N, F ramaget J. Comput ed t omography in t he et iologic assessment of idiopat hic spont aneous pneumot horax. Chest 1990;98:341–347. 104. Demos T C, Johnson C, Lov e L, et al. Comput ed t omography of part ial unilat eral agenesis of t he pec t oralis musc les. J Com put Assist T om ogr 1985;9:558–559. 105. Demos T C, Solomon C, Posniak HV, et al. Comput ed t omography in t raumat ic def ec t s of t he diaphragm. Clin Im aging 1989; 13:62–67. 106. Deslauriers J, F erraro P. Lat e c omplic at ions. In: Pierson F G, Cooper JD, Deslauriers J, et al., eds. T hor ac ic sur ger y , 2nd ed. Philadelphia: Churc hill Liv ingst one, 2002;189–207. 107. Desser T S, St ark P. Pic t orial essay : solit ary f ibrous t umor of t he pleura. J T hor ac Im aging 1998;13:27–35. 108. Dest ouet JM, Gilula LA, Murphy WA, et al. Comput ed t omography of t he st ernoc lav ic ular joint and st ernum. Radiology 1981;138:123–128. 109. Dev on RK, Rosen MA, Mies C, et al. Breast rec onst ruc t ion w it h a t ransv erse rec t us abdominis my oc ut aneous f lap: spec t rum of normal and abnormal MR imaging f indings. Radiogr aphic s 2004; 24:1287–1299. 110. Doi K, Ot suka K, Okamot o Y , et al. Cerv ic al nerv e root av ulsion in brac hial plexus injuries: magnet ic resonanc e imaging c lassif ic at ion and c omparison w it h my elography and c omput erized t omography my elography . J Neur osur g 2002;96[3 suppl]:277–284. 111. Doy le T C, Law ler GA. CT f eat ures of rounded at elec t asis of t he lung. AJR Am J Roent genol 1984;143:225–228. 112. Dw y er A. T he displac ed c rus: a sign f or dist inguishing bet w een pleural f luid and asc it es on c omput ed t omography . J Com put Assist T om ogr 1978;2:598–599. 113. Dy nes MC, Whit e EM, F ry WA, et al. Imaging manif est at ions of pleural t umors. Radiogr aphic s 1992;12:1191–1201. 114. Edelst ein G, Lev it t RG, Slaker DP, et al. CT observ at ion of rib abnormalit ies: spec t rum of f indings. J Com put Assist T om ogr 1985;9:65–72.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1420

8 - Pleura, Chest Wall, and Diaphragm 115. Einst ein DM, Singer AA, Chilc ot e WA, et al. Abdominal ly mphadenopat hy : spec t rum of CT f indings. Radiogr aphic s 1991;11:457–472. 116. England DM, Hoc hholzer L, Mc Cart hy MJ. Loc alized benign and malignant f ibrous t umors of t he pleura. A c linic opat hologic rev iew of 223 c ases. Am J Sur g Pat hol 1989;13:640–658. 117. Epler GR, Mc Loud T C, Gaensler EA. Prev alenc e and inc idenc e of benign asbest os pleural ef f usion in a w orking populat ion. JAMA 1982;247:617–622. 118. Epler GR, Mc Loud T C, Munn CS, et al. Pleural lipoma. Diagnosis by c omput ed t omography . Chest 1986;90:265–268. 119. Erasmus JJ, Mc Adams HP, Pat z EF Jr, et al. Calc if y ing f ibrous pseudot umor of pleura: radiologic f eat ures in t hree c ases. J Com put Assist T om ogr 1996;20:763–765. 120. Ernberg LA, Pot t er HG. Radiographic ev aluat ion of t he ac romioc lav ic ular and st ernoc lav ic ular joint s. Clin Spor t s Med 2003;22: 255–275. 121. Ev ans AS, Nassif RG, Ah- See KW. Spont aneous apic al lung herniat ion present ing as a nec k lump in a pat ient w it h Ehlers- Danlos sy ndrome. Sur geon 2005;3:49–51.

122. Exarhos DN, Malagari K, T sat alou EG, et al. Ac ut e mediast init is: spec t rum of c omput ed t omography f indings. Eur Radiol 2005; 15:1569–1574. 123. F aer MJ, Burnam RE, Bec k CL. T ransmural t horac ic lipoma: demonst rat ion by c omput ed t omography . AJR Am J Roent genol 1978;130:161–163. 124. F airf ax AJ, Mc Nabb WR, Spiro SG. Chy lot horax: a rev iew of 18 c ases. T hor ax 1986;41:880–885. 125. F alasc hi F , Bat t olla L, Masc alc hi M, et al. Usef ulness of MR signal int ensit y in dist inguishing benign f rom malignant pleural disease. AJR Am J Roent genol 1996;166:963–968. 126. F ederle MP, Mark AS, Guillaumin ES. CT of subpulmonic pleural ef f usions and at elec t asis: c rit eria f or dif f erent iat ion f rom subphrenic f luid. AJR Am J Roent genol 1986;146:685–689. 127. F eld R, Burk DL Jr, Mc Cue P, et al. MRI of aggressiv e f ibromat osis: f requent appearanc e of high signal int ensit y on T 2- w eight ed images. Magn Reson Im aging 1990;8:583–588. 128. F erret t i GR, Chiles C, Choplin RH, et al. Loc alized benign f ibrous t umors of t he pleura. AJR Am J Roent genol 1997;169:683–686. 129. F et sc h JF , Mont gomery EA, Meis JM. Calc if y ing f ibrous pseudot umor. Am J Sur g Pat hol 1993;17:502–508.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1421

8 - Pleura, Chest Wall, and Diaphragm 130. F isher ER, Godw in JD. Ext rapleural f at c ollec t ions: pseudot umors and ot her c onf using manif est at ions. AJR Am J Roent genol 1993; 161:47–52.

131. F ishman EK, Campbell JN, Kuhlman JE, et al. Mult i- planar CT ev aluat ion of brac hial plexopat hy in breast c anc er. J Com put Assist T om ogr 1991;15:790–795. P.659 132. F it zGerald R, Hut c hinson CE. T uberc ulosis of t he ribs: c omput ed t omographic f indings. Br J Radiol 1992;65:822–824. 133. F ly nn MW, F elson B. T he roent gen manif est at ions of t horac ic ac t inomy c osis. Am J Roent genol Radium T her Nuc l Med 1970; 110:707–716. 134. F ort ier M, May o JR, Sw ensen SJ, et al. MR imaging of c hest w all lesions. Radiogr aphic s 1994;14:597–606. 135. F ranquet T , Gimenez A, Alegret X, et al. Imaging f indings of st ernal abnormalit ies. Eur Radiol 1997;7:492–497. 136. F raser RS, Paré JAP, F raser RG, et al. Sy nopsis of diseases of t he c hest . Philadelphia: WB Saunders, 1994. 137. F riedman AC, F iel SB, F isher MS, et al. Asbest os- relat ed pleural disease and asbest osis: a c omparison of CT and c hest radiography . AJR Am J Roent genol 1988;150:269–275. 138. F riedman AC, F iel SB, Radec ki PD, et al. Comput ed t omography of benign pleural and pulmonary parenc hy mal abnormalit ies relat ed t o asbest os exposure. Sem in Ult r asound CT MR 1990;11:393–408. 139. F riedman PJ. CT demonst rat ion of t et hering of t he lung by t he pulmonary ligament . J Com put Assist T om ogr 1985;9:947–948. 140. F rija J, Y ana C, Lav al- Jeant et M. Anat omy of t he minor f issure: ev aluat ion w it h t hin- sec t ion CT . Radiology 1989;173:571–572. 141. F roehner M, Oc kert D, Bunk A, et al. Liposarc oma of t he diaphragm: CT and sonographic appearanc es. Abdom Im aging 2001;26:300–302. 142. F rost J, Georg J, Moller PF . Asbest osis w it h pleural c alc if ic at ion among insulat ion w orkers. Dan Med Bull 1956;3:202–204. 143. Gaensler EA. Lung displac ement : abdominal enlargement , pleural spac e disorders and def ormit ies of t he t horac ic c age. In: F enn W, Rahn H, eds. Handbook of phy siology , sec t ion 3: r espir at ion. Washingt on: Americ an Phy siology Soc iet y , 1965;1623–1661. 144. Gale ME. Boc hdalek hernia: prev alenc e and CT c harac t erist ic s. Radiology 1985;156:449–452.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1422

8 - Pleura, Chest Wall, and Diaphragm 145. Gale ME, Greif WL. Int raf issural f at : CT c orrelat ion w it h c hest radiography . Radiology 1986;160:333–336. 146. Gallardo X, Cast aner E, Mat a JM. Benign pleural diseases. Eur J Radiol 2000;34:87–97. 147. Gay er G, Y ellin A, Apt er S, et al. Rec onst ruc t ion of t he st ernum and c hest w all w it h met hy l met hac ry lat e: CT and MRI appearanc e. Eur Radiol 1998;8:239–243. 148. Gierada DS, Curt in JJ, Eric kson SJ, et al. Diaphragmat ic mot ion: f ast gradient - rec alled- ec ho MR imaging in healt hy subjec t s. Radiology 1995;194:879–884. 149. Gierada DS, Curt in JJ, Eric kson SJ, et al. F ast gradient ec ho magnet ic resonanc e imaging of t he normal diaphragm. J T hor ac Im aging 1997;12:70–74. 150. Gierada DS, Hakimian S, Slone RM, et al. MR analy sis of lung v olume and t horac ic dimensions in pat ient s w it h emphy sema bef ore and af t er lung v olume reduc t ion surgery . AJR Am J Roent genol 1998;170:707–714. 151. Gierada DS, Slone RM, F leishman MJ. Imaging ev aluat ion of t he diaphragm. Chest Sur g Clin N Am 1998;8:237–280.

152. Gilkeson RC, Basile V, Sands MJ, et al. Chest c ase of t he day . Morgagni's hernia. AJR Am J Roent genol 1997;169:266, 268–270. 153. Gilkeson RC, Markow it z AH, Cianc ibello L. Mult isec t ion CT ev aluat ion of t he reoperat iv e c ardiac surgery pat ient . Radiogr aphic s 2003;23(Spec no.):s3–s17. 154. Ginalski JM, Sc hny der P, Moss AA, et al. Inc idenc e and signif ic anc e of a w idened esophageal hiat us at CT sc an. J Clin Gast r oent er ol 1984;6:467–470. 155. Glazer HS, Anderson DJ, DiCroc e JJ, et al. Anat omy of t he major f issure: ev aluat ion w it h st andard and t hin- sec t ion CT . Radiology 1991;180:839–844. 156. Glazer HS, Aronberg DJ, Sagel SS, et al. Ut ilit y of CT in det ec t ing post pneumonec t omy c arc inoma rec urrenc e. AJR Am J Roent genol 1984;142:487–494. 157. Glazer HS, Dehdasht i F , Siegel F A, et al. General diagnosis c ase of t he day . AJR Am J Roent genol 1989;152:1317–1322. 158. Glazer HS, Dunc an- Mey er J, Aronberg DJ, et al. Pleural and c hest w all inv asion in bronc hogenic c arc inoma: CT ev aluat ion. Radiology 1985;157:191–194.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1423

8 - Pleura, Chest Wall, and Diaphragm 159. Glic klic h M, Mendelson DS, Gendal ES, et al. T uberc ulous empy ema nec essit at is. Comput ed t omography f indings. Clin Im aging 1990;14:23–25.

160. Godw in JD, Mac Gregor JM. Ext ension of asc it es int o t he c hest w it h hiat al hernia: v isualizat ion on CT . AJR Am J Roent genol 1987;148:31–32. 161. Godw in JD, T arv er RD. Ac c essory f issures of t he lung. AJR Am J Roent genol 1985;144:39–47. 162. Godw in JD, Voc k P, Osborne DR. CT of t he pulmonary ligament . AJR Am J Roent genol 1983;141:231–236. 163. Goodman LR, Kay HR, T eplic k SK, et al. Complic at ions of median st ernot omy : c omput ed t omographic ev aluat ion. AJR Am J Roent genol 1983;141:225–230. 164. Goodman LR, T eplic k SK, Kay H. Comput ed t omography of t he normal st ernum. AJR Am J Roent genol 1983;141:219–223. 165. Gouda H, Mult z AS, Khan A, et al. Lung hernia as a sequela t o limit edac c ess mit ral v alv e surgery . T ex Hear t Inst J 2002;29:203–205. 166. Gouliamos AD, Cart er BL, Emami B. Comput ed t omography of t he c hest w all. Radiology 1980;134:433–436. 167. Grant DC, Selt zer SE, Ant man KH, et al. Comput ed t omography of malignant pleural mesot helioma. J Com put Assist T om ogr 1983;7:626–632. 168. Gray H. Gr ay 's anat om y . Philadelphia: Lea and F ebiger, 1985. 169. Grif f in DJ, Gross BH, Mc Crac ken S, et al. Observ at ions on CT dif f erent iat ion of pleural and perit oneal f luid. J Com put Assist T om ogr 1984;8:24–28. 170. Grillo HC, Shepard JA, Mat hisen DJ, et al. Post pneumonec t omy sy ndrome: diagnosis, management , and result s. Ann T hor ac Sur g 1992;54:638–650; disc ussion 650–651. 171. Gut h AA, Pac ht er HL, Kim U. Pit f alls in t he diagnosis of blunt diaphragmat ic injury . Am J Sur g 1995;170:5–9. 172. Haddad CJ, Sim WK. Empy ema nec essit at is. Am F am Phy sic ian 1989;40:149–152. 173. Hagay C, Cherel PJ, Maulmont CE, et al. Cont rast - enhanc ed CT : v alue f or diagnosing loc al breast c anc er rec urrenc e af t er c onserv at iv e t reat ment . Radiology 1996;200:631–638. 174. Hagman T F , Winer- Muram HT , Mey er CA, et al. Int rat horac ic splenosis: superiorit y of t ec hnet ium T c 99m heat - damaged RBC imaging. Chest 2001;120:2097–2098.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1424

8 - Pleura, Chest Wall, and Diaphragm 175. Haller JA Jr, Kramer SS, Liet man SA. Use of CT sc ans in selec t ion of pat ient s f or pec t us exc av at um surgery : a preliminary report . J Pediat r Sur g 1987;22:904–906.

176. Halv orsen RA, F edy shin PJ, Korobkin M, et al. Asc it es or pleural ef f usion? CT dif f erent iat ion: f our usef ul c rit eria. Radiogr aphic s 1986;6:135–149. 177. Halv orsen RA, F edy shin PJ, Korobkin M, et al. CT dif f erent iat ion of pleural ef f usion f rom asc it es. An ev aluat ion of f our signs using blinded analy sis of 52 c ases. Inv est Radiol 1986;21:391–395. 178. Hammerman AM, Susman N, St rzembosz A, et al. T he ext rapleural f at sign: CT c harac t erist ic s. J Com put Assist T om ogr 1990;14:345–347. 179. Hansell DM, Armst rong P, Ly nc h DA, et al. Inhalat ional lung disease. In: Im aging of diseases of t he c hest . Philadelphia: Elsev ier Mosby , 2005;429–484. 180. Hansell DM, Armst rong P, Ly nc h DA, et al. Neoplasms of t he lungs, airw ay s, and pleura. In: Im aging of diseases of t he c hest . Philadelphia: Elsev ier Mosby , 2005;785–899. 181. Hansell DM, Armst rong P, Ly nc h DA, et al. Pleura and pleural disorders. In: Im aging of diseases of t he c hest . Philadelphia: Elsev ier Mosby , 2005;1023–1092. 182. Harden SP, Argent JD, Blaquiere RM. Painf ul sc lerosis of t he medial end of t he c lav ic le. Clin Radiol 2004;59:992–999. 183. Harker CP, St ern EJ, F rank MS. Hemidiaphragm paraly sis: CT diagnosis. J T hor ac Im aging 1994;9:166–168. 184. Hasan F M, Nash G, Kazemi H. Asbest os exposure and relat ed neoplasia. T he 28 y ear experienc e of a major urban hospit al. Am J Med 1978;65:649–654. 185. Hat f ield MK, Gross BH, Glazer GM, et al. Comput ed t omography of t he st ernum and it s art ic ulat ions. Skelet al Radiol 1984;11: 197–203. 186. Hav eas J, v anSonnenberg E, Casola G, et al. Perc ut aneous drainage of inf ec t ed and noninf ec t ed t horac ic f luid c ollec t ions. J T hor ac Im aging 1987;2:80–87. 187. Hazelrigg SR, St aller B. Migrat ion of st ernal w ire int o asc ending aort a. Ann T hor ac Sur g 1994;57:1023–1024. 188. Heat er K, Rev zani L, Rubin JM. CT ev aluat ion of empy ema in t he post pneumonec t omy spac e. AJR Am J Roent genol 1985;145: 39–40. P.660

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1425

8 - Pleura, Chest Wall, and Diaphragm

189. Heelan RT , Demas BE, Carav elli JF , et al. Superior sulc us t umors: CT and MR imaging. Radiology 1989;170:637–641. 190. Heelan RT , Rusc h VW, Begg CB, et al. St aging of malignant pleural mesot helioma: c omparison of CT and MR imaging. AJR Am J Roent genol 1999;172:1039–1047. 191. Heiberg E, Wolv erson MK, Hurd RN, et al. CT rec ognit ion of t raumat ic rupt ure of t he diaphragm. AJR Am J Roent genol 1980; 135:369–372. 192. Hems T E, Birc h R, Carlst edt T . T he role of magnet ic resonanc e imaging in t he management of t rac t ion injuries t o t he adult brac hial plexus. J Hand Sur g [Br ] 1999;24:550–555. 193. Hensc hke CI, Dav is SD, Romano PM, et al. Pleural ef f usions: pat hogenesis, radiologic ev aluat ion, and t herapy . J T hor ac Im aging 1989;4:49–60. 194. Hensc hke CI, Y ankelev it z DF , Dav is SD. Pleural diseases: mult imodalit y imaging and c linic al management . Cur r Pr obl Diagn Radiol 1991;20:155–181. 195. Herborn CU, Marinc ek B, Erf mann D, et al. Breast augment at ion and rec onst ruc t iv e surgery : MR imaging of implant rupt ure and malignanc y . Eur Radiol 2002;12:2198–2206. 196. Hernandez F J, F ernandez BB. Loc alized f ibrous t umors of pleura: a light and elec t ron mic rosc opic st udy . Canc er 1974;34:1667–1674. 197. Hert h F , Ernst A, Bec ker HD. Endosc opic drainage of lung absc esses: t ec hnique and out c ome. Chest 2005;127:1378–1381. 198. Hert zanu Y , Solomon A. Inv ersion of t he right diaphragm: a t horac oabdominal CT pit f all. Gast r oint est Radiol 1986;11:200–202. 199. Hierholzer J, Luo L, Bit t ner RC, et al. MRI and CT in t he dif f erent ial diagnosis of pleural disease. Chest 2000;118:604–609. 200. Hillerdal G. Malignant mesot helioma 1982: rev iew of 4710 published c ases. Br J Dis Chest 1983;77:321–343. 201. Hillerdal G. Pleural plaques and risk f or bronc hial c arc inoma and mesot helioma. A prospec t iv e st udy . Chest 1994;105:144–150. 202. Hillerdal G. Chy lot horax and pseudoc hy lot horax. Eur Respir J 1997; 10:1157–1162. 203. Holbert BL, Holbert JM, Libshit z HI. CT of int erpec t oral ly mph nodes. AJR Am J Roent genol 1987;149:687–688. 204. Huang W, F isher PR, Dulaimy K, et al. Det ec t ion of breast malignanc y : diagnost ic MR prot oc ol f or improv ed spec if ic it y . Radiology 2004;232:585–591.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1426

8 - Pleura, Chest Wall, and Diaphragm

205. Hudson T M. F luid lev els in aneury smal bone c y st s: a CT f eat ure. AJR Am J Roent genol 1984;142:1001–1004. 206. Hugget t JM, Roszler MH. CT f indings of st ernal f rac t ure. Injur y 1998;29:623–626. 207. Hughes RS. Malignant pleural mesot helioma. Am J Med Sc i 2005;329:29–44. 208. Hulnic k DH, Naidic h DP, Mc Cauley DI. Pleural t uberc ulosis ev aluat ed by c omput ed t omography . Radiology 1983;149:759–765. 209. Hy odoh K, Hy odoh H, Akiba H, et al. Brac hial plexus: normal anat omy and pat hologic al c ondit ions. Cur r Pr obl Diagn Radiol 2002;31:179–188. 210. Ikegami T , Ezaki T , Ishida T , et al. Neurilemmoma of t he diaphragm mimic king a liv er t umor: c ase report . Abdom Im aging 2004;29:85–86. 211. Im JG, Chung JW, Han MC. Milk of c alc ium pleural c ollec t ions: CT f indings. J Com put Assist T om ogr 1993;17:613–616. 212. Im J- G, Kang HS, Choi BI, et al. Pleural endomet riosis: CT and sonographic f indings. AJR Am J Roent genol 1987;148:523–524. 213. Im JG, Webb WR, Rosen A, et al. Cost al pleura: appearanc es at highresolut ion CT . Radiology 1989;171:125–131. 214. Inoue M, Sano T , Wat ai R, et al. Dy namic mult idet ec t or CT of breast t umors: diagnost ic f eat ures and c omparison w it h c onv ent ional t ec hniques. AJR Am J Roent genol 2003;181:679–686. 215. Inoue T , T amaki Y , Hamada S, et al. Usef ulness of t hree- dimensional mult idet ec t or- row CT images f or preoperat iv e ev aluat ion of t umor ext ension in primary breast c anc er pat ient s. Br east Canc er Res T r eat 2005;89:119–125. 216. Insko EK, Lev ine MS, Birnbaum BA, et al. Benign and malignant lesions of t he st omac h: ev aluat ion of CT c rit eria f or dif f erent iat ion. Radiology 2003;228:166–171. 217. Ioc hum S, Ludig T , Walt er F , et al. Imaging of diaphragmat ic injury : a diagnost ic c hallenge? Radiogr aphic s 2002;22[Spec No]: s103–s116; disc ussion s116–s118. 218. Israel RS, May berry JC, Primac k SL. Diaphragmat ic rupt ure: use of helic al CT sc anning w it h mult iplanar ref ormat ions. AJR Am J Roent genol 1996;167:1201–1203. 219. Iw asaw a T , Kagei S, Got oh T , et al. Magnet ic resonanc e analy sis of abnormal diaphragmat ic mot ion in pat ient s w it h emphy sema. Eur Respir J 2002;19:225–231.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1427

8 - Pleura, Chest Wall, and Diaphragm 220. Iw asaw a T , Kaw amot o M, Y oshiike Y , et al. Normal in- plane respirat ory mot ion of t he bilat eral hemidiaphragms ev aluat ed by sequent ially subt rac t ed f ast magnet ic resonanc e images. J T hor ac Im aging 1999;14:130–134. 221. Iw asaw a T , Y oshiike Y , Sait o K, et al. Paradoxic al mot ion of t he hemidiaphragm in pat ient s w it h emphy sema. J T hor ac Im aging 2000;15:191–195. 222. Jac ob G, Bohig H. Roent genologic c omplic at ions in pulmonary asbest osis. Rof o 1955;83:515–525.

223. Jaf ri SZH, Robert s JL, Bree RL, et al. Comput ed t omography of c hest w all masses. Radiogr aphic s 1989;9:51–68. 224. Jee WH, Choi KH, Choe BY , et al. F ibrous dy splasia: MR imaging c harac t erist ic s w it h radiopat hologic c orrelat ion. AJR Am J Roent genol 1996;167:1523–1527. 225. Jeung MY , Gangi A, Gasser B, et al. Imaging of c hest w all disorders. Radiogr aphic s 1999;19:617–637. 226. Jolles H, Henry DA, Roberson JP, et al. Mediast init is f ollow ing median st ernot omy : CT f indings. Radiology 1996;201:463–466. 227. Jones JS. T he pleura in healt h and disease. Lung 2001;179: 397–413. 228. Jones RN, Mc Loud T , Roc kof f SD. T he radiographic pleural abnormalit ies in asbest os exposure: relat ionship t o phy siologic abnormalit ies. J T hor ac Im aging 1988;3:57–66. 229. Jung JI, Kim HH, Park SH, et al. T horac ic manif est at ions of breast c anc er and it s t herapy . Radiogr aphic s 2004;24:1269–1285. 230. Kanemat su M, Imaeda T , Moc hizuki R, et al. Dy namic MRI of t he diaphragm. J Com put Assist T om ogr 1995;19:67–72. 231. Kaniklides C, Dimopoulos PA. Diaphragmat ic haemangioma. A c ase report . Ac t a Radiol 1999;40:329–332. 232. Karabulut N, Goodman LR. Pedunc ulat ed solit ary f ibrous t umor of t he int erlobar f issure: a w andering c hest mass. AJR Am J Roent genol 1999;173:476–477. 233. Kaw LL Jr, Pot enza BM, Coimbra R, et al. T raumat ic diaphragmat ic hernia. J Am Coll Sur g 2004;198:668–669. 234. Kaw ashima A, Kuhlman JE, F ishman EK, et al. Pulmonary Aspergillus c hest w all inv olv ement in c hronic granulomat ous disease: CT and MRI f indings. Skelet al Radiol 1991;20:487–493. 235. Kaw ashima A, Libshit z HI. Malignant pleural mesot helioma: CT manif est at ions in 50 c ases. AJR Am J Roent genol 1990;155: 965–969.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1428

8 - Pleura, Chest Wall, and Diaphragm 236. Kee ST , Gamsu G, Blanc P. Causes of pulmonary impairment in asbest osexposed indiv iduals w it h dif f use pleural t hic kening. Am J Respir Cr it Car e Med 1996;154:789–793.

237. Kennedy L, Sahn SA. T alc pleurodesis f or t he t reat ment of pneumot horax and pleural ef f usion. Chest 1994;106:1215–1222. 238. Khalil A, Le Bret on C, T assart M, et al. Ut ilit y of CT sc an f or t he diagnosis of c hest w all t uberc ulosis. Eur Radiol 1999;9: 1638–1642. 239. Kic hari JR, Hussain SM, Den Hollander JC, et al. MR imaging of t he brac hial plexus: c urrent imaging sequenc es, normal f indings, and f indings in a spec t rum of f oc al lesions w it h MR- pat hologic c orrelat ion. Cur r Pr obl Diagn Radiol 2003;32:88–101. 240. Killeen KL, Mirv is SE, Shanmuganat han K. Helic al CT of diaphragmat ic rupt ure c aused by blunt t rauma. AJR Am J Roent genol 1999; 173:1611–1616. 241. Kim F M, F ennessy JJ. Pleural t hic kening c aused by leukemic inf ilt rat ion: CT f indings. AJR Am J Roent genol 1994;162:293–294. 242. Kim HY , Song KS, Goo JM, et al. T horac ic sequelae and c omplic at ions of t uberc ulosis. Radiogr aphic s 2001;21:839–858; disc ussion 859–860. 243. Kim HY , Song KS, Lee HJ, et al. Pariet al pleura and ext rapleural spac e in c hronic t uberc ulous empy ema: CT - pat hologic c orrelat ion. J Com put Assist T om ogr 2001;25:9–15. 244. Kim JT , Y oon Y H, Baek WK, et al. My osit is ossif ic ans of t he c hest w all simulat ing malignant neoplasm. Ann T hor ac Sur g 2000; 70:1718–1720. P.661 245. Kim SJ, IM JG, Cho ST , et al. Rib c ount ing on CT using t he st ernal approac h. J Com put Assist T om ogr 1993;17:358–362. 246. Kim SM, Park JM. Comput ed t omography of t he breast . Abnormal f indings w it h mammographic and sonographic c orrelat ion. J Com put Assist T om ogr 2003;27:761–770. 247. Kiv iluot o R. Pleural c alc if ic at ion as a roent genologic sign of nonoc c upat ional endemic ant hophy llit e- asbest osis. Ac t a Radiolog 1960;194(suppl):1–67. 248. Klima M, Spjut HJ, Sey bold WD. Dif f use malignant mesot helioma. Am J Clin Pat hol 1976;65:583–600. 249. Knisely BL, Broderic k LS, Kuhlman JE. MR imaging of t he pleura and c hest w all. Magn Reson Im aging Clin Nor t h Am 2000;8: 125–141. 250. Ko SF , Wan Y L, Ng SH, et al. Imaging f eat ures of at y pic al t horac ic Cast leman disease. Clin Im aging 2004;28:280–285.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1429

8 - Pleura, Chest Wall, and Diaphragm 251. Kodalli N, Erzen C, Y uksel M. Ev aluat ion of pariet al pleural inv asion of lung c anc ers w it h breat hhold inspirat ion and expirat ion MRI. Clin Im aging 1999;23:227–235. 252. Kori SH, F oley KM, Posner JB. Brac hial plexus lesions in pat ient s w it h c anc er: 100 c ases. Neur ology 1981;31:45–50. 253. Kot ani T , Minami S, T akahashi K, et al. An analy sis of c hest w all and

diaphragm mot ions in pat ient s w it h idiopat hic sc oliosis using dy namic breat hing MRI. Spine 2004;29:298–302. 254. Koy ama S, Araki M, Suzuki K, et al. Primary diaphragmat ic sc hw annoma w it h a t y pic al t arget appearanc e: c orrelat ion of CT and MR imagings and hist ologic f indings. J Gast r oent er ol 1996; 31:268–272. 255. Kransdorf MJ, Moser RP Jr, Gilkey F W. F ibrous dy splasia. Radiogr aphic s 1990;10:519–537. 256. Krumhaar D, Lange S, Hart mann C, et al. F ollow - up st udy of 100 malignant pleural mesot heliomas. T hor ac Car diov asc Sur g 1985; 33:272–275. 257. Kuhlman JE, Bouc hardy L, F ishman EK, et al. CT and MR imaging ev aluat ion of c hest w all disorders. Radiogr aphic s 1994;14: 571–595. 258. Kuhlman JE, Pozniak MA, Collins J, et al. Radiographic and CT f indings of blunt c hest t rauma: aort ic injuries and looking bey ond t hem. Radiogr aphic s 1998;18:1085–1106; disc ussion 1107–1108; quiz 1. 259. Kuhlman JE, Sc at arige JC, F ishman EK, et al. CT demonst rat ion of high at t enuat ion pleural- parenc hy mal lesions due t o amiodarone t herapy . J Com put Assist T om ogr 1987;11:160–162. 260. Kuhlman JE, Singha NK. Complex disease of t he pleural spac e: radiographic and CT ev aluat ion. Radiogr aphic s 1997;17:63–79. 261. Kumar H, Rat h G, Sharma M, et al. Bilat eral st ernalis w it h unusual lef t sided present at ion: a c linic al perspec t iv e. Y onsei Med J 2003;44:719–722. 262. Kumar R, Madew ell JE, Sw isc huk LE, et al. T he c lav ic le: normal and abnormal. Radiogr aphic s 1989;9:677–706. 263. Kurihara Y , Nakajima Y , Ishikaw a T , et al. Count ing ribs on c hest CT sc ans: t he easiest w ay . AJR Am J Roent genol 1995;165:487. 264. Kw ong JS, Muller NL, Godw in JD, et al. T horac ic ac t inomy c osis: CT f indings in eight pat ient s. Radiology 1992;183:189–192. 265. Lai- F ook SJ. Pleural mec hanic s and f luid exc hange. Phy siol Rev 2004;84:385–410.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1430

8 - Pleura, Chest Wall, and Diaphragm 266. Lamba M, Jabi M, Padmore R, et al. Isolat ed pleural pt ld af t er c ardiac t ransplant at ion. Car diov asc Pat hol 2002;11:346–350.

267. Landw ehr P, Sc hult e O, Lac kner K. MR imaging of t he c hest : mediast inum and c hest w all. Eur Radiol 1999;9:1737–1744. 268. Lang- Lazdunski L, Bonnet PM, Pons F , et al. T raumat ic ext rat horac ic lung herniat ion. Ann T hor ac Sur g 2002;74:927–929. 269. Lanphear BP, Bunc her CR. Lat ent period f or malignant mesot helioma of oc c upat ional origin. J Oc c up Med 1992;34:718–721. 270. Laric i AR, Got w ay MB, Lit t HI, et al. Helic al CT w it h sagit t al and c oronal rec onst ruc t ions: ac c urac y f or det ec t ion of diaphragmat ic injury . AJR Am J Roent genol 2002;179:451–457. 271. Lauf er L, Sc hulman H, Hert zanu Y . Int rat horac ic rib demonst rat ed by helic al CT w it h t hree- dimensional rec onst ruc t ion. Eur Radiol 1999;9:60–61. 272. Law t on F , Blac kledge G, Johnson R. Co- exist ent c hy lous and serous pleural ef f usions assoc iat ed w it h ov arian c anc er: a c ase report of Cont arini's sy ndrome. Eur J Sur g Onc ol 1985;11:177–178. 273. Leat hart GL. Pulmonary f unc t ion t est s in asbest os w orkers. T r ans Soc Oc c up Med 1968;18:49–55. 274. Lee CH. Problem solv ing MR imaging of t he breast . Radiol Clin Nor t h Am 2004;42:919–934, v ii. 275. Lee G, Im JG, Kim JS, et al. T uberc ulosis of t he ribs: CT appearanc e. J Com put Assist T om ogr 1993;17:363–366. 276. Lee JK, Y ao L, Wirt h CR. MR imaging of solit ary ost eoc hondromas: report of eight c ases. AJR Am J Roent genol 1987;149:557–560. 277. Lee KH, Song KS, Kw on Y , et al. Mesenc hy mal t umours of t he t horax: CT f indings and pat hologic al f eat ures. Clin Radiol 2003; 58:934–944. 278. Lee KS, Im JG, Choe KO, et al. CT f indings in benign f ibrous mesot helioma of t he pleura: pat hologic c orrelat ion in nine pat ient s. AJR Am J Roent genol 1992;158:983–986. 279. Lee MJ, Sallomi DF , Munk PL, et al. Pic t orial rev iew : giant c ell t umours of bone. Clin Radiol 1998;53:481–489. 280. Lee VS, Mart inez S, Coleman RE. Primary musc le ly mphoma: c linic al and imaging f indings. Radiology 1997;203:237–244. 281. LePage MA, Kazerooni EA, Helv ie MA, et al. Breast rec onst ruc t ion w it h t ram f laps: normal and abnormal appearanc es at CT . Radiogr aphic s 1999;19:1593–1603.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1431

8 - Pleura, Chest Wall, and Diaphragm 282. Lesur O, Delorme N, F romaget JM, et al. Comput ed t omography in t he et iologic assessment of idiopat hic spont aneous pneumot horax. Chest 1990;98:341–347. 283. Leung AN, Müller NL, Miller RR. CT in dif f erent ial diagnosis of dif f use pleural disease. AJR Am J Roent genol 1990;154: 487–492. 284. Leung JC, Nanc e ML, Sc hw ab CW, et al. T hic kening of t he diaphragm: a new c omput ed t omography sign of diaphragm injury . J T hor ac Im aging 1999;14:126–129. 285. Lev insohn EM, Bunnell WP, Y uan HA. Comput ed t omography in t he diagnosis of disloc at ions of t he st ernoc lav ic ular joint . Clin Or t hop Relat Res 1979;140:12–16. 286. Liberman L, Morris EA, Dershaw DD, et al. MR imaging of t he ipsilat eral breast in w omen w it h perc ut aneously prov en breast c anc er. AJR Am J Roent genol 2003;180:901–910. 287. Liberman L, Morris EA, Lee MJ, et al. Breast lesions det ec t ed on MR imaging: f eat ures and posit iv e predic t iv e v alue. AJR Am J Roent genol 2002;179:171–178. 288. Libshit z I, Holbert JM. Ant erior diaphragmat ic ly mph nodes. Ly m phology 1988;21:99–104.

289. Lieberman PH, Jones CR, Dargeon HWK, et al. A reappraisal of eosinophilic granuloma of bone, Hand- Sc hüller- Christ ian sy ndrome and Let t erer- Siw e sy ndrome. Medic ine (Balt im or e) 1969; 48:375–400. 290. Light RW. T alc should not be used f or pleurodesis. Am J Respir Cr it Car e Med 2000;162:2024–2026. 291. Light RW. Disorders of t he pleura, mediast inum, and diaphragm. In: Braunw ald E, F auc i AS, Kasper DL, et al., eds. Har r ison's pr inc iples of int er nal m edic ine, 15t h ed. New Y ork: Mc Graw - Hill, 2001;1513–1516. 292. Lindf ors KK, Mey er JE, Busse PM, et al. CT ev aluat ion of loc al and regional breast c anc er rec urrenc e. AJR Am J Roent genol 1985;145:833–837. 293. Lingaw i SS, Bilbey JH, Munk PL, et al. MR imaging of brac hial plexopat hy in breast c anc er pat ient s w it hout palpable rec urrenc e. Skelet al Radiol 1999;28:318–323. 294. Londero V, Bazzoc c hi M, Del F rat e C, et al. Loc ally adv anc ed breast c anc er: c omparison of mammography , sonography and MR imaging in ev aluat ion of residual disease in w omen rec eiv ing neoadjuv ant c hemot herapy . Eur Radiol 2004;14:1371–1379.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1432

8 - Pleura, Chest Wall, and Diaphragm 295. Lorigan JG, Libshit z HI. MR imaging of malignant pleural mesot helioma. J Com put Assist T om ogr 1989;13:617–620. 296. Loy er EM, Kroll SS, Dav id CL, et al. Mammographic and CT f indings af t er

breast rec onst ruc t ion w it h a rec t us abdominis musc uloc ut aneous f lap. AJR Am J Roent genol 1991;156:1159–1162. 297. Luc et L, Le Loet X, Menard JF , et al. Comput ed t omography of t he normal st ernoc lav ic ular joint . Skelet al Radiol 1996;25: 237–241. 298. Ly nc h DA, Gamsu G, Aberle DR. Conv ent ional and high resolut ion c omput ed t omography in t he diagnosis of asbest os- relat ed diseases. Radiogr aphic s 1989;9:523–551. P.662 299. Mac Eneaney P, Visw esw aran A, F ennessy J, et al. Supernumerary int rat horac ic ribs: imaging f eat ures of t w o c ases. J T hor ac Im aging 2001;16:123–126. 300. Maddern IR, Goodman LR, Almassi GH, et al. CT af t er rec onst ruc t iv e repair of t he st ernum and c hest w all. Radiology 1993; 186:665–670. 301. Magdeleinat P, Alif ano M, Pet ino A, et al. Solit ary f ibrous t umors of t he pleura: c linic al c harac t erist ic s, surgic al t reat ment and out c ome. Eur J Car diot hor ac Sur g 2002;21:1087–1093. 302. Malloy PC, F ishman EK, Magid D. Ly mphoma of bone, musc le, and skin: CT f indings. AJR Am J Roent genol 1992;159: 805–809. 303. Marin ML, Aust in JHM, Markow it z AM. Elast of ibroma dorsi: CT demonst rat ion. J Com put Assist T om ogr 1987;11:675–677. 304. Marks BW, Kuhns LR. Ident if ic at ion of t he pleural f issures w it h c omput ed t omography . Radiology 1982;143:139–141. 305. Mason AC, Miller BH, Krasna MJ, et al. Ac c urac y of CT f or t he det ec t ion of pleural adhesions: c orrelat ion w it h v ideo- assist ed t horac osc opic surgery . Chest 1999;115:423–427. 306. Mat a J, Cac eres J, Alegret X, et al. Imaging of t he azy gos lobe: normal anat omy and v ariat ions. AJR Am J Roent genol 1991; 156:931–937. 307. Mat t hay RA, Coppage L, Shaw C, et al. Malignanc ies met ast at ic t o t he pleura. Inv est Radiol 1990;25:601–619. 308. Mc Adams HP, Gordon DS, Whit e CS. Apic al lung hernia: radiologic f indings in six c ases. AJR Am J Roent genol 1996;167:927–930. 309. Mc Donald AD, Mc Donald JC. Malignant mesot helioma in Nort h Americ a. Canc er 1980;46:1650–1656.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1433

8 - Pleura, Chest Wall, and Diaphragm 310. Mc Hugh K, Blaquiere RM. CT f eat ures of rounded at elec t asis. AJR Am J Roent genol 1989;153:257–260.

311. Mc Loud T C. T he pleura and c hest w all. In: Haaga JR, Lanzieri CF , Sart oris DJ, et al., eds. Com put ed t om ogr aphy and m agnet ic r esonanc e im aging of t he w hole body , 3rd ed. St . Louis: Mosby , 1994;772–787. 312. Mc Loud T C. CT and MR in pleural disease. Clin Chest Med 1998;19:261–276. 313. Mc Loud T C, F low er CDR. Imaging of t he pleura: sonography , CT , and MR imaging. AJR Am J Roent genol 1991;156: 1145–1153. 314. Mc Loud T C, Woods BO, Carringt on CB, et al. Dif f use pleural t hic kening in an asbest os- exposed populat ion: prev alenc e and c auses. AJR Am J Roent genol 1985;144:9–18. 315. Mendelson DS, Meary E, Buy JN, et al. Loc alized f ibrous pleural mesot helioma: CT f indings. J Clin Im aging 1991;15:105–108. 316. Mergo PJ, Helmberger T , Didov ic J, et al. New f ormula f or quant if ic at ion of pleural ef f usions f rom c omput ed t omography . J T hor ac Im aging 1999;14:122–125. 317. Met int as M, Uc gun I, Elbek O, et al. Comput ed t omography f eat ures in malignant pleural mesot helioma and ot her c ommonly seen pleural diseases. Eur J Radiol 2002;41:1–9. 318. Mey er CA, Whit e CS. Cart ilaginous disorders of t he c hest . Radiogr aphic s 1998;18:1109–1123; quiz 1241–1242. 319. Mey ers BF , Mc Cabe CJ. T raumat ic diaphragmat ic hernia. Oc c ult marker of serious injury . Ann Sur g 1993;218:783–790. 320. Mihos P, Pot aris K, Gakidis J, et al. T raumat ic rupt ure of t he diaphragm: experienc e w it h 65 pat ient s. Injur y 2003;34:169–172. 321. Miller A, T eirst ein AS, Selikof f IJ. Vent ilat ory f ailure due t o asbest os pleurisy . Am J Med 1983;75:911–919. 322. Miller BH, Rosado- de- Christ enson ML, Mason AC, et al. F rom t he arc hiv es of t he af ip. Malignant pleural mesot helioma: radiologic - pat hologic c orrelat ion. Radiogr aphic s 1996;16:613–644. 323. Minami M, Kaw auc hi N, Y oshikaw a K, et al. Malignanc y assoc iat ed w it h c hronic empy ema: radiologic assessment . Radiology 1991;178:417–423. 324. Minat o M, Hirose C, Sasa M, et al. 3- dimensional c omput ed t omography ly mphography - guided ident if ic at ion of sent inel ly mph nodes in breast c anc er pat ient s using subc ut aneous injec t ion of nonionic c ont rast medium: a c linic al t rial. J Com put Assist T om ogr 2004;28:46–51.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1434

8 - Pleura, Chest Wall, and Diaphragm 325. Mint zer RA, Gore RM, Vogelzang RL, et al. Rounded at elec t asis and it s assoc iat ion w it h asbest os- induc ed pleural disease. Radiology 1981;139:567–570.

326. Mirilas P, Siat it sas Y , Skandalakis JE. Benign anat omic al mist akes: inf erior pulmonary ligament . Am Sur g 2002;68:922–926. 327. Mirv is S, Dut c her JP, Haney PJ, et al. CT of malignant pleural mesot helioma. AJR Am J Roent genol 1983;140:665–670. 328. Mirv is SE. Diagnost ic imaging of ac ut e t horac ic injury . Sem in Ult r asound CT MR 2004;25:156–179. 329. Misaw a Y , F use K, Hasegaw a T . Inf ec t ious mediast init is af t er c ardiac operat ions: c omput ed t omographic f indings. Ann T hor ac Sur g 1998;65:622–624. 330. Miy ake H, Shiga M, T akaki H, et al. Mediast inal ly mphangiomas in adult s: CT f indings. J T hor ac Im aging 1996;11:83–85. 331. Mogav ero GT , F ishman EK, Kuhlman JE. Inf lammat ory breast c anc er: CT ev aluat ion. Clin Im aging 1992;16:183–186. 332. Moran CA, T rav is WD, Rosado- de- Christ enson M, et al. T hy momas present ing as pleural t umors. Report of eight c ases. Am J Sur g Pat hol 1992;16:138–144. 333. Morgan DE, Nat h H, Sanders C, et al. Case report : mediast inal ac t inomy c osis. AJR Am J Roent genol 1990;155:735–737. 334. Mori K. Vasc ular anat omy at t he medial ends of inc omplet e major f issures. J T hor ac Im aging 2003;18:190–194. 335. Morris BS, Maheshw ari M, Chalw a A. Chest w all t uberc ulosis: a rev iew of CT appearanc es. Br J Radiol 2004;77:449–457. 336. Morris EA. Breast c anc er imaging w it h MRI. Radiol Clin Nor t h Am 2002;40:443–466. 337. Morrison WB, Sc hw eit zer ME, Boc k GW, et al. Diagnosis of ost eomy elit is: ut ilit y of f at - suppressed c ont rast - enhanc ed MR imaging. Radiology 1993;189:251–257. 338. Mount ain CF . Rev isions in t he Int ernat ional Sy st em f or St aging Lung Canc er. Chest 1997;111:1710–1717. 339. Muller NL. Imaging of t he pleura. Radiology 1993;186:297–309. 340. Mullins ME, St ein J, Saini SS, et al. Prev alenc e of inc ident al Boc hdalek's hernia in a large adult populat ion. AJR Am J Roent genol 2001;177:363–366. 341. Munden RF , Libshit z HI. Rounded at elec t asis and mesot helioma. AJR Am J Roent genol 1998;170:1519–1522.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1435

8 - Pleura, Chest Wall, and Diaphragm 342. Munk PL, Muller NL. Pleural liposarc oma: CT diagnosis. J Com put Assist T om ogr 1988;12:709–710.

343. Murat a K, T akahashi M, Mori M, et al. Chest w all and mediast inal inv asion by lung c anc er: ev aluat ion w it h mult isec t ion expirat ory dy namic CT . Radiology 1994;191:251–255. 344. Murphey MD, Nomikos GC, F lemming DJ, et al. F rom t he arc hiv es of AF IP. Imaging of giant c ell t umor and giant c ell reparat iv e granuloma of bone: radiologic - pat hologic c orrelat ion. Radiogr aphic s 2001;21:1283–1309. 345. Murray JG, Caoili E, Gruden JF , et al. Ac ut e rupt ure of t he diaphragm due t o blunt t rauma: diagnost ic sensit iv it y and spec if ic it y of CT . AJR Am J Roent genol 1996;166:1035–1039. 346. Murray JG, Pat z EF , Jr., Erasmus JJ, et al. CT appearanc e of t he pleural spac e af t er t alc pleurodesis. AJR Am J Roent genol 1997; 169:89–91. 347. Nahir B, Eldar- Gev a T , Albert on J, et al. Sy mpt omat ic diaphragmat ic endomet riosis t en y ears af t er t ot al abdominal hy st erec t omy . Obst et Gy nec ol 2004;104:1149–1151. 348. Naidic h DP, Megibow AJ, Hilt on S, et al. Comput ed t omography of t he diaphragm: peridiaphragmat ic f luid loc alizat ion. J Com put Assist T om ogr 1983;7:641–649. 349. Naidic h DP, Zerhouni EA, Siegelman SS. Com put ed t om ogr aphy of t he t hor ax. New Y ork: Rav en Press, 1984. 350. Naidic h DP, Zerhouni EA, Siegelman SS. Pleura and c hest w all. In: Com put ed t om ogr aphy and m agnet ic r esonanc e of t he t hor ax. New Y ork: Rav en, 1991;407–471. 351. Nakahara H, Namba K, Wakamat su H, et al. Ext ension of breast c anc er: c omparison of CT and MRI. Radiat Med 2002; 20:17–23. 352. Naunheim KS. Adult present at ion of unusual diaphragmat ic hernias. Chest Sur g Clin N Am 1998;8:359–369. 353. Nc himi A, Szapiro D, Ghay e B, et al. Helic al CT of blunt diaphragmat ic rupt ure. AJR Am J Roent genol 2005;184:24–30. 354. Nef f CC, v anSonnenberg E, Law son DW, et al. CT f ollow - up of empy emas: pleural peels resolv e af t er perc ut aneous c at het er drainage. Radiology 1990;176:195–197. 355. Ng CS, Munden RF , Libshit z HI. Malignant pleural mesot helioma: t he spec t rum of manif est at ions on CT in 70 c ases. Clin Radiol 1999;54:415–421. 356. Ng SB, Ahmed Q, T ien SL, et al. Primary pleural sy nov ial sarc oma. A c ase report and rev iew of t he lit erat ure. Ar c h Pat hol Lab Med 2003;127:85–90.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1436

8 - Pleura, Chest Wall, and Diaphragm P.663 357. Nisolle JF , Delaunois L, T rigaux JP. My osit is ossif ic ans of t he c hest w all. Eur Respir J 1996;9:178–179.

358. Noppen M, De Waele M, Li R, et al. Volume and c ellular c ont ent of normal pleural f luid in humans examined by pleural lav age. Am J Respir Cr it Car e Med 2000;162:1023–1026. 359. Normand JP, Rioux M, Dumont M, et al. T horac ic splenosis af t er blunt t rauma: f requenc y and imaging f indings. AJR Am J Roent genol 1993;161:739–741. 360. Nov ic k SL, F ishman EK. Ant erior mediast inal ext ension of primary c hest w all inf ec t ions: role of spiral CT in det ec t ion and management . Cr it Rev Com put T om ogr 2003;44:79–93. 361. Okby NT , T rav is WD. Liposarc oma of t he pleural c av it y : c linic al and pat hologic f eat ures of 4 c ases w it h a rev iew of t he lit erat ure. Ar c h Pat hol Lab Med 2000;124:699–703. 362. Olaf sson G, Rausing A, Holen O. Primary t umors of t he diaphragm. Chest 1971;59:568–570. 363. O'Meara JB, Slade PR. Disappearanc e of f luid f rom t he post pneumonec t omy spac e. J T hor ac Car diov asc Sur g 1974;67:621–628. 364. Ont ell F K, Moore EH, Shepard JA, et al. T he c ost al c art ilages in healt h and disease. Radiogr aphic s 1997;17:571–577. 365. Orel SG, Sc hnall MD. MR imaging of t he breast f or t he det ec t ion, diagnosis, and st aging of breast c anc er. Radiology 2001;220: 13–30. 366. Ort ega W, Mahboubi S, Dalinka MK, et al. Comput ed t omography of rib hemangiomas. J Com put Assist T om ogr 1986;10:945–947. 367. Ot suji H, Uc hida H, Maeda M, et al. Inc omplet e int erlobar f issures: bronc hov asc ular analy sis w it h CT . Radiology 1993;187:541–546. 368. Padov ani B, Mouroux J, Seksik L, et al. Chest w all inv asion by bronc hogenic c arc inoma: ev aluat ion w it h MR imaging. Radiology 1993;187:33–38. 369. Pairolero PC, Arnold PG. Chest w all t umors. Experienc e w it h 100 c onsec ut iv e pat ient s. J T hor ac Car diov asc Sur g 1985;90:367–372. 370. Paling MR, Grif f in GK. Low er lobe c ollapse due t o pleural ef f usion: a CT analy sis. J Com put Assist T om ogr 1985;9:1079–1083. 371. Panic ek DM, Benson CB, Got t lieb RH, et al. T he diaphragm: anat omic , pat hologic , and radiologic c onsiderat ions. Radiogr aphic s 1988;8:385–425.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1437

8 - Pleura, Chest Wall, and Diaphragm 372. Parient y RA, Maric hez M, Pradel J, et al. Pararenal pseudot umors of t he diaphragm: c omput ed t omographic f eat ures. Gast r oint est Radiol 1987;12:131–133. 373. Part ridge SC, Gibbs JE, Lu Y , et al. Ac c urac y of MR imaging f or rev ealing residual breast c anc er in pat ient s w ho hav e undergone neoadjuv ant c hemot herapy . AJR Am J Roent genol 2002;179: 1193–1199. 374. Pat selas T N, Gallagher EG. T he diagnost ic dilemma of diaphragm injury . Am Sur g 2002;68:633–639. 375. Pat z EF Jr, Rusc h VW, Heelan R. T he proposed new int ernat ional t nm

st aging sy st em f or malignant pleural mesot helioma: applic at ion t o imaging. AJR Am J Roent genol 1996;166:323–327. 376. Pat z EF Jr, Shaf f er K, Piw nic a- Worms DR, et al. Malignant pleural mesot helioma: v alue of CT and MR imaging in predic t ing resec t abilit y . AJR Am J Roent genol 1992;159:961–966. 377. Pearson F G, Cooper JD, Ilv es R, et al. Massiv e hiat al hernia w it h inc arc erat ion: a report of 53 c ases. Ann T hor ac Sur g 1983;35:45–51. 378. Pec orari A, Weisbrod GL. Comput ed t omography of pseudot umoral pleural f luid c ollec t ions in t he azy goesophageal rec ess. J Com put Assist T om ogr 1989;13:803–805. 379. Pet ers JC, Desai KK. CT demonst rat ion of post pneumonec t omy t umor rec urrenc e. AJR Am J Roent genol 1983;141:259–262. 380. Pet o J, Hodgson JT , Mat t hew s F E, et al. Cont inuing inc rease in mesot helioma mort alit y in Brit ain. Lanc et 1995;345:535–539. 381. Pic c oli CW, Greer JG, Mit c hell DG. Breast MR imaging f or c anc er det ec t ion and implant ev aluat ion: pot ent ial pit f alls. Radiogr aphic s 1996;16:63–75. 382. Pilla T J, Wolv erson MK, Sundaram M, et al. CT ev aluat ion of c y st ic ly mphangiomas of t he mediast inum. Radiology 1982;144:841–842. 383. Pisani RJ, Colby T V, Williams DE. Malignant mesot helioma of t he pleura. May o Clin Pr oc 1988;63:1234–1244. 384. Plat how C, Ley S, F ink C, et al. Ev aluat ion of c hest mot ion and v olumet ry during t he breat hing c y c le by dy namic MRI in healt hy subjec t s: c omparison w it h pulmonary f unc t ion t est s. Inv est Radiol 2004;39:202–209. 385. Posniak HV, Olson MC, Dudiak CM, et al. MR imaging of t he brac hial plexus. AJR Am J Roent genol 1993;161:373–379. 386. Pramesh CS, Madur BP, Raina S, et al. Angiosarc oma of t he pleura. Ann T hor ac Car diov asc Sur g 2004;10:187–190.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1438

8 - Pleura, Chest Wall, and Diaphragm 387. Press GA, Glazer HS, Wasserman T H, et al. T horac ic w all inv olv ement by Hodgkin disease and non- Hodgkin ly mphoma: CT ev aluat ion. Radiology 1985;157:195–198. 388. Pric e B. Analy sis of c urrent t rends in Unit ed St at es mesot helioma inc idenc e. Am J Epidem iol 1997;145:211–218. 389. Propec k T , Eust ac e S. Ret rost ernal disloc at ion of t he c lav ic le w it h t rac heal c ompression: appearanc e on t hree- dimensional CT . AJR Am J Roent genol 1996;167:1067–1068. 390. Prot o AV, Ball JB Jr. Comput ed t omography of t he major and minor f issures. AJR Am J Roent genol 1983;140:439–448. 391. Puls R, Kreissig R, Host en N, et al. T umour of t he diaphragm mimic king liv er lesion. Eur J Radiol 2002;41:168–169. 392. Qay y um A, Mac Vic ar AD, Padhani AR, et al. Sy mpt omat ic brac hial plexopat hy f ollow ing t reat ment f or breast c anc er: ut ilit y of MR imaging w it h surf ac e- c oil t ec hniques. Radiology 2000;214:837–842. 393. Rabinow it z JG, Cohen BA, Mendleson DS. Sy mposium on Nonpulmonary Aspec t s in Chest Radiology . T he pulmonary ligament . Radiol Clin Nor t h Am 1984;22:659–672. 394. Rabinow it z JG, Ef remidis SC, Cohen B, et al. A c omparat iv e st udy of mesot helioma and asbest osis using c omput ed t omography and c onv ent ional c hest radiography . Radiology 1982;144:453–460.

395. Rabinow it z JG, Wolf BS. Roent gen signif ic anc e of t he pulmonary ligament . Radiology 1966;87:1013–1020. 396. Radic h GA, Alt inok D, Silv a J. Marked migrat ion of st ernot omy w ires: a c ase report . J T hor ac Im aging 2004;19:117–119. 397. Randall PA, T rasolini NC, Kohman LJ, et al. MR imaging t he ev aluat ion of t he c hest af t er unc omplic at ed median st ernot omy . Radiogr aphic s 1993;13:329–340. 398. Rankine JJ. Adult t raumat ic brac hial plexus injury . Clin Radiol 2004;59:767–774. 399. Rapoport S, Blair DN, Mc Cart hy SM, et al. Brac hial plexus: c orrelat ion of MR imaging w it h CT and pat hologic f indings. Radiology 1988;167:161–165. 400. Reif f DA, Mc Gw in G Jr, Met zger J, et al. Ident if y ing injuries and mot or v ehic le c ollision c harac t erist ic s t hat t oget her are suggest iv e of diaphragmat ic rupt ure. J T r aum a 2002;53:1139–1145.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1439

8 - Pleura, Chest Wall, and Diaphragm 401. Reina A, Vidana E, Soriano P, et al. T raumat ic int raperic ardial diaphragmat ic hernia: c ase report and lit erat ure rev iew . Injur y 2001;32:153–156. 402. Remy - Jardin M, Sobaszek A, Duhamel A, et al. Asbest os- relat ed pleuropulmonary diseases: ev aluat ion w it h low - dose f our- det ec t or row spiral CT . Radiology 2004;233:182–190. 403. Ren H, Hruban RH, Kuhlman JE, et al. Comput ed t omography of rounded at elec t asis. Case report . J Com put Assist T om ogr 1988; 12:1031–1034. 404. Resnic k D. St ernoc ost oc lav ic ular hy perost osis. AJR Am J Roent genol 1980;135:1278–1280.

405. Ric c i ZJ, Haramat i LB, Rosenbaum AT , et al. Role of c omput ed t omography in guiding t he management of peripheral bronc hopleural f ist ula. J T hor ac Im aging 2002;17:214–218. 406. Roac h HD, Dav ies GJ, At t anoos R, et al. Asbest os: w hen t he dust set t les an imaging rev iew of asbest os- relat ed disease. Radiogr aphic s 2002;22(Spec no.):s167–s184. 407. Rosado- de- Christ enson ML, Abbot t GF , Mc Adams HP, et al. F rom t he arc hiv es of t he AF IP: loc alized f ibrous t umor of t he pleura. Radiogr aphic s 2003;23:759–783. 408. Rosen A, Auh Y H, Rubenst ein WA, et al. CT appearanc e of diaphragmat ic pseudot umors. J Com put Assist T om ogr 1983;7: 995–999. 409. Rosen EL, Blac kw ell KL, Baker JA, et al. Ac c urac y of MRI in t he det ec t ion of residual breast c anc er af t er neoadjuv ant c hemot herapy . AJR Am J Roent genol 2003;181:1275–1282. 410. Rosenblut h DB. Pleural ef f usions: nonmalignant and malignant . In: F ishman AP, Elias JA, F ishman JA, et al., eds. F ishm an's m anual of pulm onar y diseases and disor der s, 3rd ed. New Y ork: Mc Graw - Hill, 2002; 487–506. 411. Rost RC J Prot o AV. Inf erior pulmonary ligament : c omput ed t omographic appearanc e. Radiology 1983;148:479–483. 412. Rouv iere H, T obias MJ. Anat om y of t he ly m phat ic sy st em . Ann Arbor, MI: Edw ards Bros. Inc ., 1938;86–88. 413. Rozenblit A, Iqbal A, Kaley a R, et al. Case report : int radiaphragmat ic bronc hogenic c y st . Clin Radiol 1998;53:918–920. P.664 414. Rubikas R. Diaphragmat ic injuries. Eur J Car diot hor ac Sur g 2001;20:53–57.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1440

8 - Pleura, Chest Wall, and Diaphragm 415. Rusc a M, Carbognani P, Cat t elani L, et al. Spont aneous int erc ost al pulmonary hernia. J Car diov asc Sur g (T or ino) 2000;41:641–642. 416. Rusc h VW, Godw in JD, Shuman WP. T he role of c omput ed t omography sc anning in t he init ial assessment and t he f ollow - up of malignant pleural mesot helioma. J T hor ac Car diov asc Sur g 1988;96:171–177. 417. Rusc h VW. A proposed new int ernat ional t nm st aging sy st em f or malignant pleural mesot helioma. F rom t he Int ernat ional Mesot helioma Int erest Group. Chest 1995;108:1122–1128. 418. Rusc h VW, Piant adosi S, Holmes EC. T he role of ext rapleural

pneumonec t omy in malignant pleural mesot helioma. A Lung Canc er St udy Group t rial. J T hor ac Car diov asc Sur g 1991;102:1–9. 419. Sabant han S, Salama F D, Morgan WE, et al. Primary c hest w all t umors. Ann T hor ac Sur g 1985;39:4–15. 420. Sadeghi N, Nic aise N, DeBac ker D, et al. Right diaphragmat ic rupt ure and hepat ic hernia: an indirec t sign on c omput ed t omography . Eur Radiol 1999;9:972–974. 421. Saggia C, F ort i G, Biaggi G, et al. T w o c ases of sec ondary sof t t issue sarc omas af t er radiot herapy and radioc hemot herapy . T um or i 2004;90:622–624. 422. Sahin AA, Çöplü L, Selçuk ZT , et al. Malignant pleural mesot helioma c aused by env ironment al exposure t o asbest os or erionit e in rural T urkey : CT f indings in 84 pat ient s. AJR Am J Roent genol 1993;161:533–537. 423. Sahn SA. Pleural diseases relat ed t o met ast at ic malignanc ies. Eur Respir J 1997;10:1907–1913. 424. Sahn SA. T alc should be used f or pleurodesis. Am J Respir Cr it Car e Med 2000;162:2023–2024; disc ussion 2026. 425. Saif uddin A. Imaging t umours of t he brac hial plexus. Skelet al Radiol 2003;32:375–387. 426. Sakai S, Muray ama S, Murakami J, et al. Bronc hogenic c arc inoma inv asion of t he c hest w all: ev aluat ion w it h dy namic c ine MRI during breat hing. J Com put Assist T om ogr 1997;21:595–600. 427. Sakamot o T , Kaneshige H, T akeshi A, et al. Loc alized pleural mesot helioma w it h elev at ion of high molec ular w eight insulin- like grow t h f ac t or II and hy pogly c emia. Chest 1994;106:965–967. 428. Sakamot o T , Miy amot o Y , Nishio W, et al. Empy ema nec essit at is int o t he ret roperit oneal spac e. Ann T hor ac Sur g 2002;73:1954–1956.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1441

8 - Pleura, Chest Wall, and Diaphragm 429. Salc edo JR. Urinot horax: report of f our c ases and rev iew of t he lit erat ure. J Ur ol 1986;135:805–808. 430. Sardanelli F , Lozzelli A, F aust o A. MR imaging of t he breast : indic at ions, est ablished t ec hnique, and new direc t ions. Eur Radiol 2003;13[suppl 3]:N28–N36. 431. Sargent EN, Bosw ell WD Jr, Ralls PW, et al. Subpleural f at pads in pat ient s exposed t o asbest os: dist inc t ion f rom nonc alc if ied pleural plaques. Radiology 1984;152:273–277. 432. Sc alzet t i EM, Heit zman ER, Groskin SA, et al. Dev elopment al ly mphat ic disorders of t he t horax. Radiogr aphic s 1991;11:1069–1085.

433. Sc harif ker D, Kaneko M. Loc alized f ibrous “ mesot helioma” of pleura (submesot helial f ibroma): a c linic opat hologic st udy of 18 c ases. Canc er 1979;43:627–635. 434. Sc hluet er F J, Mc Clennan BL. Massiv e asc it es and pleural ef f usions assoc iat ed w it h endomet riosis. Abdom Im aging 1994;19: 475–476. 435. Sc hnall MD. Breast MR imaging. Radiol Clin Nor t h Am 2003;41: 43–50. 436. Sc hneller J. Mult if oc al glomangiomy omas in t he c hest w all of a y oung man. Ar c h Pat hol Lab Med 2001;125:1146–1147. 437. Sc href f ler AJ, Rumisek JD. Int rav asc ular migrat ion of f rac t ured st ernal w ire present ing w it h hemopt y sis. Ann T hor ac Sur g 2001;71:1682–1684. 438. Sc hw art z EE, Wec hsler RJ. Diaphragmat ic and paradiaphragmat ic t umors and pseudot umors. J T hor ac Im aging 1989;4:19–28. 439. Sc ot t EM, Marshall T J, F low er CD, et al. Dif f use pleural t hic kening: perc ut aneous CT - guided c ut t ing needle biopsy . Radiology 1995; 194:867–870. 440. Seat on D. Regional lung f unc t ion in asbest os w orkers. T hor ax 1977;32:40–44. 441. Seo BK, Pisano ED, Cho KR, et al. Low - dose mult idet ec t or dy namic CT in t he breast : preliminary st udy . Clin Im aging 2005;29:172–178. 442. Serry C, Blec k P, Jav id H, et al. St ernal w ound c omplic at ions. Management and result s. J T hor ac Car diov asc Sur g 1980;80: 861–867. 443. Shac klet on KL, St ew art ET , T ay lor AJ. T raumat ic diaphragmat ic injuries: spec t rum of radiographic f indings. Radiogr aphic s 1998; 18:49–59. 444. Shaf f er K, Rosado- de- Christ enson ML, Pat z EF Jr, et al. T horac ic ly mphangioma in adult s: CT and MR imaging f eat ures. AJR Am J Roent genol 1994;162:283–289.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1442

8 - Pleura, Chest Wall, and Diaphragm 445. Shah J, Pat kar D, Parikh B, et al. T uberc ulosis of t he st ernum and c lav ic le: imaging f indings in 15 pat ient s. Skelet al Radiol 2000;29: 447–453. 446. Shanmuganat han K, Mirv is SE, Chiu WC, et al. Penet rat ing t orso t rauma: t riple- c ont rast helic al CT in perit oneal v iolat ion and organ injury —a prospec t iv e st udy in 200 pat ient s. Radiology 2004;231:775–784. 447. Shanmuganat han K, Mirv is SE, Whit e CS, et al. MR imaging ev aluat ion of hemidiaphragms in ac ut e blunt t rauma: experienc e w it h 16 pat ient s. AJR Am J Roent genol 1996;167:397–402. 448. Sharif HS, Clark DC, Aabed MY , et al. MR imaging of t horac ic and

abdominal w all inf ec t ions: c omparison w it h ot her imaging proc edures. AJR Am J Roent genol 1990;154:989–995. 449. Sharma A, F idias P, Hay man LA, et al. Pat t erns of ly mphadenopat hy in t horac ic malignanc ies. Radiogr aphic s 2004;24:419–434. 450. Shea WJ Jr, de Geer G, Webb WR. Chest w all af t er mast ec t omy . Part I. CT appearanc e of normal post operat iv e anat omy , post irradiat ion c hanges, and opt imal sc anning t ec hniques. Radiology 1987;162:157–161. 451. Shea WJ Jr, de Geer G, Webb WR. Chest w all af t er mast ec t omy . Part II. CT appearanc e of t umor rec urrenc e. Radiology 1987;162: 162–164. 452. Shepard JA, Grillo HC, Mc Loud T C, et al. Right - pneumonec t omy sy ndrome: radiologic f indings and CT c orrelat ion. Radiology 1986; 161:661–664. 453. Sherrier RH, Sost man HD. Magnet ic resonanc e imaging of t he brac hial plexus. J T hor ac Im aging 1993;8:27–33. 454. Shin MS, Berland LL. Comput ed t omography of ret roc rural spac es: normal, anat omic v ariant s, and pat hologic c ondit ions. AJR Am J Roent genol 1985;145:81–86. 455. Shirakaw a T , F ukuda K, Miy amot o Y , et al. Pariet al pleural inv asion of lung masses: ev aluat ion w it h CT perf ormed during deep inspirat ion and expirat ion. Radiology 1994;192:809–811. 456. Shuman LS, Libshit z HI. Solid pleural manif est at ions of ly mphoma. AJR Am J Roent genol 1984;142:269–273. 457. Siegmann KC, Muller- Sc himpf le M, Sc hic k F , et al. MR imaging- det ec t ed breast lesions: hist opat hologic c orrelat ion of lesion c harac t erist ic s and signal int ensit y dat a. AJR Am J Roent genol 2002;178:1403–1409. 458. Silv erman PM, Baker ME, Mahony BS. At elec t asis and subpulmonic f luid: a CT pit f all in dist inguishing pleural f rom perit oneal f luid. J Com put Assist T om ogr 1985;9:763–766.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1443

8 - Pleura, Chest Wall, and Diaphragm 459. Silv erman PM, Cooper C, Zeman RK. Lat eral arc uat e ligament s of t he diaphragm: anat omic v ariat ions at abdominal CT . Radiology 1992;185:105–108.

460. Silv erman PM, Godw in JD, Korobkin M. Comput ed t omographic det ec t ion of ret roc rural air. AJR Am J Roent genol 1982; 138:825–827. 461. Silv erman SG, Mueller PR, Saini S, et al. T horac ic empy ema: management w it h image- guided c at het er drainage. Radiology 1988;169:5–9. 462. Singh B, East w ood PR, F inuc ane KE, et al. Ef f ec t of asbest os- relat ed pleural f ibrosis on exc ursion of t he low er c hest w all and diaphragm. Am J Respir Cr it Car e Med 1999;160:1507–1515. 463. Sof ranik RM, Gross BH, Spizarny DL. Radiology of t he pleural f issures. Clin Im aging 1992;16:221–229. 464. Solomon A. Radiologic f eat ures of dif f use mesot helioma. Env ir on Res 1970;3:330–338. 465. Song JW, Im JG, Goo JM, et al. Pseudoc hy lous pleural ef f usion w it h f at f luid lev els: report of six c ases. Radiology 2000; 216: 478–480. 466. Soo MS, Korngut h PJ, Walsh R, et al. Complex radial f olds v ersus subt le signs of int rac apsular rupt ure of breast implant s: MR f indings w it h surgic al c orrelat ion. AJR Am J Roent genol 1996; 166:1421–1427. 467. Spec kman JM, Gamsu G, Webb WR. Alt erat ions in CT mediast inal anat omy produc ed by an azy gos lobe. AJR Am J Roent genol 1981;137:47–50. P.665 468. Spizarny DL, Gross BH, Shepard JA. CT f indings in loc alized f ibrous mesot helioma of t he pleural f issure. J Com put Assist T om ogr 1986;10:942–944. 469. St ark DD, F ederle MP, Goodman PC. CT and radiographic assessment of t ube t horac ost omy . AJR Am J Roent genol 1983;141:253–258. 470. St ark DD, F ederle MP, Goodman PC, et al. Dif f erent iat ing lung absc ess and empy ema: radiography and c omput ed t omography . AJR Am J Roent genol 1983;141:163–167. 471. St ark P, Jaramillo D. CT of t he st ernum. AJR Am J Roent genol 1986;147:72–77. 472. St ark P, Wat kins GE, Hildebrandt - St ark HE, et al. Epist ernal ossic les. Radiology 1987;165:143–144. 473. St einer RM, Cooper MW, Brodov sky H. Rib dest ruc t ion: a neglec t ed f inding in malignant mesot helioma. Clin Radiol 1982;33:61–65.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1444

8 - Pleura, Chest Wall, and Diaphragm 474. St ern EJ, Sun H, Haramat i LB. Peripheral bronc hopleural f ist ulas: CT imaging f eat ures. AJR Am J Roent genol 1996;167:117–120. 475. Suga K, T sukuda T , Aw ay a H, et al. Impaired respirat ory mec hanic s in pulmonary emphy sema: ev aluat ion w it h dy namic breat hing MRI. J Magn Reson Im aging 1999;10:510–520. 476. Suga K, Y uan Y , Okada M, et al. Breast sent inel ly mph node mapping at CT ly mphography w it h iopamidol: preliminary experienc e. Radiology 2004;230:543–552. 477. Sussman SK, Halv orsen RA Jr, Silv erman PM, et al. Parac ardiac adenopat hy : CT ev aluat ion. AJR Am J Roent genol 1987;149:29–34. 478. T aguc hi S, Niibori T , Moro K. Use of t hree- dimensional c omput ed t omography images in dec iding t he approac h f or minist ernot omy operat ions. Ann T hor ac Sur g 2000;70:1090–1093. 479. T akasugi JE, Godw in JD. Lef t azy gos lobe. Radiology 1989;171: 133–134. 480. T akazakura R, T akahashi M, Nit t a N, et al. Diaphragmat ic mot ion in t he sit t ing and supine posit ions: healt hy subjec t st udy using a v ert ic ally open magnet ic resonanc e sy st em. J Magn Reson Im aging 2004;19:605–609.

481. T angoku A, Y amamot o S, Suga K, et al. Sent inel ly mph node biopsy using c omput ed t omography - ly mphography in pat ient s w it h breast c anc er. Sur ger y 2004;135:258–265. 482. T arv er RD, Conc es DJ Jr, Cory DA, et al. Imaging t he diaphragm and it s disorders. J T hor ac Im aging 1989;4:1–18. 483. T at eishi U, Gladish GW, Kusumot o M, et al. Chest w all t umors: radiologic f indings and pat hologic c orrelat ion: part 1. Benign t umors. Radiogr aphic s 2003;23:1477–1490. 484. T at eishi U, Gladish GW, Kusumot o M, et al. Chest w all t umors: radiologic f indings and pat hologic c orrelat ion: part 2. Malignant t umors. Radiogr aphic s 2003;23:1491–1508. 485. T at eishi U, Nishihara H, Morikaw a T , et al. Solit ary f ibrous t umor of t he pleura: MR appearanc e and enhanc ement pat t ern. J Com put Assist T om ogr 2002;26:174–179. 486. T av akkolizadeh A, Saif uddin A, Birc h R. Imaging of adult brac hial plexus t rac t ion injuries. J Hand Sur g [Br ] 2001;26:183–191. 487. T emplet on PA, F ishman EK. CT ev aluat ion of post st ernot omy c omplic at ions. AJR Am J Roent genol 1992;159:45–50.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1445

8 - Pleura, Chest Wall, and Diaphragm

488. T eplic k JG, T eplic k SK, Goodman L, et al. T he int erf ac e sign: a c omput ed t omographic sign f or dist inguishing pleural and int ra- abdominal f luid. Radiology 1982;144:359–362. 489. T heros EG, F eigin DS. Pleural t umors and pulmonary t umors: dif f erent ial diagnosis. Sem in Roent genol 1977;12:239–247. 490. T oc ino I, Miller MH. Comput ed t omography in blunt c hest t rauma. J T hor ac Im aging 1987;2:45–59. 491. T odd M, Shah GV, Mukherji SK. MR imaging of brac hial plexus. T op Magn Reson Im aging 2004;15:113–125. 492. T resallet C, Menegaux F , Izzillo R, et al. Usef ulness of CT rec onst ruc t ed pic t ures f or diaphragmat ic rupt ure af t er blunt t rauma. J Am Coll Sur g 2004;198:666–667. 493. T sai JC, Dalinka MK, F allon MD, et al. F luid- f luid lev el: a nonspec if ic f inding in t umors of bone and sof t t issue. Radiology 1990;175:779–782. 494. Unal O, Arslan H, Uzun K, et al. Ev aluat ion of diaphragmat ic mov ement w it h MR f luorosc opy in c hronic obst ruc t iv e pulmonary disease. Clin Im aging 2000;24:347–350. 495. Ut z JA, Kransdorf MJ, Jelinek JS, et al. MR appearanc e of f ibrous dy splasia. J Com put Assist T om ogr 1989;13:845–851. 496. Van Cleemput J, De Raev e H, Versc hakelen JA, et al. Surf ac e of loc alized pleural plaques quant it at ed by c omput ed t omography sc anning: no relat ion w it h c umulat iv e asbest os exposure and no ef f ec t on lung f unc t ion. Am J Respir Cr it Car e Med 2001;163: 705–710. 497. v an Es HW. MRI of t he brac hial plexus. Eur Radiol 2001;11: 325–336. 498. Van Goet hem M, Sc helf out K, Dijc kmans L, et al. MR mammography in t he pre- operat iv e st aging of breast c anc er in pat ient s w it h dense breast t issue: c omparison w it h mammography and ult rasound. Eur Radiol 2004;14:809–816. 499. Van Es HW, Wit kamp T D, F eldberg MAM. MRI of t he brac hial plexus and it s region: anat omy and pat hology . Eur Radiol 1995;5:145–151. 500. Varma DG, Ay ala AG, Carrasc o CH, et al. Chondrosarc oma: MR imaging w it h pat hologic c orrelat ion. Radiogr aphic s 1992;12: 687–704. 501. Vas W, Malpani AR, Singer J, et al. Comput ed t omographic ev aluat ion of paraesophageal hernia. Gast r oint est Radiol 1989; 14:291–294. 502. Versc hakelen JA, Demaerel P, Coolen J, et al. Rounded at elec t asis of t he lung: MR appearanc e. AJR Am J Roent genol 1989;152: 965–966. 503. Vibhakar SD, Bellon EM. T he bare area of t he spleen: a c onst ant CT f eat ure of t he asc it ic abdomen. AJR Am J Roent genol 1984; 142:953–955.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1446

8 - Pleura, Chest Wall, and Diaphragm 504. Vix VA. Ext rapleural c ost al f at . Radiology 1974;112:563–565. 505. Wac hsberg RH, Maldjian PD, Simmons MZ, et al. Cardiophrenic angle v aric es in port al hy pert ension. Radiology 1994; 193(suppl):234. 506. Wagner JC, Sleggs CA, Marc hand P. Dif f use pleural mesot helioma and asbest os exposure in t he Nort h West ern Cape Prov inc e. Br J Ind Med 1960;17:260–271. 507. Wait e RJ, Carbonneau RJ, Balikian JP, et al. Pariet al pleural c hanges in empy ema: appearanc e at CT . Radiology 1990;175: 145–150. 508. Wall SD, F ederle MP, Jef f rey RB, et al. CT diagnosis of unsuspec t ed pneumot horax af t er blunt abdominal t rauma. AJR Am J Roent genol 1983;141:919–921. 509. Wallenhaupt SL. Surgic al management of t horac ic empy ema. J T hor ac Im aging 1991;6:80–88. 510. Wallner B, Edelman RR, F inn JP, et al. Bright pleural ef f usion and asc it es on gradient - ec ho MR images: a pot ent ial sourc e of c onf usion in v asc ular MR st udies. AJR Am J Roent genol 1990;155:1237–1240. 511. Wang ZJ, Reddy GP, Got w ay MB, et al. Malignant pleural mesot helioma: ev aluat ion w it h CT , MR imaging, and PET . Radiogr aphic s 2004;24:105–119. 512. Wat anabe A, Shimokat a K, Saka H, et al. Chest CT c ombined w it h art if ic ial pneumot horax: v alue in det ermining origin and ext ent of t umor. AJR Am J Roent genol 1991;156:707–710. 513. Webb WR, Gat sonis C, Zerhouni EA, et al. CT and MR imaging in st aging non- small c ell bronc hogenic c arc inoma: report of t he Radiologic Diagnost ic Onc ology Group. Radiology 1991;178: 705–713. 514. Weber MA, Boc k M, Plat how C, et al. Asbest os- relat ed pleural disease: v alue of dedic at ed magnet ic resonanc e imaging t ec hniques. Inv est Radiol 2004;39:554–564. 515. Wec hsler RJ. CT of esophageal- pleural f ist ulae. AJR Am J Roent genol 1986;147:907–909. 516. Wec hsler RJ, St einer RM. Cross- sec t ional imaging of t he c hest w all. J T hor ac Im aging 1989;4:29–40.

517. Wec hsler RJ, St einer RM, Conant EF . Oc c upat ionally induc ed neoplasms of t he lung and pleura. Radiol Clin Nor t h Am 1992; 30:1245–1268. 518. Weissberg D, Ref aely Y . Hernia of t he lung. Ann T hor ac Sur g 2002; 74:1963–1966. 519. Weksler B, Ginsberg RJ. T umors of t he diaphragm. Chest Sur g Clin N Am 1998;8:441–447.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1447

8 - Pleura, Chest Wall, and Diaphragm

520. West c ot t JL, Volpe JP. Peripheral bronc hopleural f ist ula: CT ev aluat ion in 20 pat ient s w it h pneumonia, empy ema, or post operat iv e air leak. Radiology 1995;196:175–181. 521. Wey ant MJ, F lores RM. Imaging of pleural and c hest w all t umors. T hor ac Sur g Clin 2004;14:15–23. 522. Williamson BRJ, Gouse JC, Rohrer DG, et al. Variat ion in t he t hic kness of t he diaphragmat ic c rura w it h respirat ion. Radiology 1987;163:683–684. P.666 523. Willif ord ME, Godw in JD. Comput ed t omography of lung absc ess and empy ema. Radiol Clin Nor t h Am 1983;21:575–583. 524. Winer- Muram HT , Kauf f man WM, Gronemey er SA, et al. Primit iv e neuroec t odermal t umors of t he c hest w all (Askin t umors): CT and MR f indings. AJR Am J Roent genol 1993;161: 265–268. 525. Wit t enberg KH, Adkins MC. MR imaging of nont raumat ic brac hial plexopat hies: f requenc y and spec t rum of f indings. Radiogr aphic s 2000;20:1023–1032. 526. Woert ler K. Benign bone t umors and t umor- like lesions: v alue of c rosssec t ional imaging. Eur Radiol 2003;13:1820–1835. 527. Woodring JH, Bognar B. Musc ular hy pert rophy of t he lef t diaphragmat ic c rus: an unusual c ause of a paraspinal “ mass.” J T hor ac Im aging 1998;13:144–145. 528. Wort hy SA, Kang EY , Hart man T E, et al. Diaphragmat ic rupt ure: CT f indings in 11 pat ient s. Radiology 1995;194:885–888. 529. Y amaguc hi T , Hay ashi K, Ashizaw a K, et al. Magnet ic resonanc e imaging of rounded at elec t asis. J T hor ac Im aging 1997;12: 188–194. 530. Y ang WT , Mut t arak M, Ho LW. Nonmammary malignanc ies of t he breast : ult rasound, CT , and MRI. Sem in Ult r asound CT MR 2000;21:375–394. 531. Y okoi K, Mori K, Miy azaw a N, et al. T umor inv asion of t he c hest w all and mediast inum in lung c anc er: ev aluat ion w it h pneumot horax CT . Radiology 1991;181:147–152. 532. Y ousem SA. T horac ic splenosis. Ann T hor ac Sur g 1987;44:411–412. 533. Zellos L, Christ iani DC. Epidemiology , biologic behav ior, and nat ural hist ory of mesot helioma. T hor ac Sur g Clin 2004;14: 469–477, v iii. 534. Zerhouni EA, Sc ot t WW Jr, Baker RR, et al. Inv asiv e t hy momas: diagnosis and ev aluat ion by c omput ed t omography . J Com put Assist T om ogr 1982;6:92–100.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1448

8 - Pleura, Chest Wall, and Diaphragm 535. Zimmer WD, Berquist T H, Sim F H, et al. Magnet ic resonanc e imaging of aneury smal bone c y st . May o Clin Pr oc 1984;59: 633–636.

536. Zinn WL, Naidic h DP, Whelan CA, et al. F luid w it hin preexist ing pulmonary air- spac es: a pot ent ial pit f all in CT dif f erent iat ion of pleural f rom parenc hy mal disease. J Com put Assist T om ogr 1987;11: 441–448. 537. Zoc c hi L. Phy siology and pat hophy siology of pleural f luid t urnov er. Eur Respir J 2002;20:1545–1558.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

9 - Heart and Pericardium

1450

9 - Heart and Pericardium 14

9 - Heart and Pericardium Editors: Le e , Jose ph K. T. ; Sa ge l, Stua rt S. ; Sta nle y , Robe rt J. ; He ike n, Ja y P. Title : C ompute d Body Tomogra phy with MRI C orre la tion , 4th Edition Copy right В©2006 Lippinc ot t Williams & Wilkins > T able of Cont ent s > 9 - Heart and Peric ardium

9 Heart and Pericardium Pa me la K. Wooda rd Sa nje e v Bha lla C y le n Ja v ida n- Ne ja d Pa ul D. Ste in F e rna ndo R. Gutie rre z Cardiov asc ular disease is t he major c ause of deat h in t he West ern w orld. More t han 70 million Americ ans hav e c ardiov asc ular disease (6). Predominant ly t his is c oronary art ery disease, but it also inc ludes c ongenit al heart disease and ot her f orms of ac quired heart disease, suc h as v alv ular disease, c ardiomy opat hies, t umors, and peric ardial proc esses. In 2002, an est imat ed 1.5 million inv asiv e diagnost ic c ardiac c at het erizat ions w ere perf ormed (6). Cardiac c omput ed t omography (CT ) and magnet ic resonanc e imaging (MRI) c an be minimally inv asiv e alt ernat iv es t o c ardiac c at het erizat ion, prov iding anat omic al and—w it h MRI and new er mult idet ec t or (MDCT ) sy st ems—f unc t ional inf ormat ion. Alt hough ec hoc ardiography is also noninv asiv e and more port able and w idely av ailable t han MR or MDCT , MRI and CT hav e t he adv ant age of t hree- dimensional (3D) c ov erage of t he heart . T hus, imaging result s are less operat or- dependent . Indeed, f or c ert ain c ardiac indic at ions, MRI and CT hav e bec ome t he gold st andard. T his is t he c ase w it h c ardiac MR imaging f or lef t v ent ric ular f unc t ion and my oc ardial mass. In t his c hapt er w e address t he t ec hnic al aspec t s of MDCT and MR imaging of t he heart , along w it h spec if ic indic at ions f or t heir use and diagnosis of disease ent it ies.

TECHNIQUE

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1451

9 - Heart and Pericardium Cardiac CT

Rec ent progression in mult idet ec t or c omput ed t omography (MDCT ) t ec hnology has adv anc ed it s c apabilit y in t he diagnosis of c ardiac disease. Spec if ic ally , t he progression f rom single- and dual- det ec t or sy st ems t o 4- det ec t or, and now 16- t o 64- det ec t or sy st ems, has allow ed improv ed c oronary CT angiography , leading t o bet t er c oronary lesion v isibilit y (42,75,94). Cardiac CT , in t erms of prot oc ol, c an broadly be broken dow n int o f our c at egories: · Coronary CT angiography · Calc ium sc oring · ECG- gat ed nonc oronary c ont rast - enhanc ed c ardiac imaging (e.g., peric ardial disease, c ongenit al heart disease) · Non–ECG- gat ed c ont rast - enhanc ed c ardiac image f or pulmonary v ein mapping T he lat t er prot oc ol is non–ECG- gat ed, as t hese pat ient s usually are in at rial f ibrillat ion w it h an irregular c ardiac rhy t hm.

Image Acquisition and Technique Cardiac Gating Unlike CT imaging of ot her organ sy st ems, CT imaging of t he heart requires met hods t o dec rease c ardiac mot ion art if ac t s. T w o basic met hods c an be used: prospec t iv e elec t roc ardiogram (ECG)- t riggering (also know n as sequent ial sc anning) and ret rospec t iv e ECG- gat ing (89,102). Wit h prospec t iv e ECG- t riggering, a signal is deriv ed f rom t he R- w av e of t he pat ient 's ECG (F ig. 9- 1). Using t his t rigger, sc anning is perf ormed ov er a f init e port ion of t he R- R int erv al, usually in diast ole, during t he period of least c ardiac mot ion. T his t ec hnique is used in elec t ron beam t omography (EBT ) and also c an be used in mult idet ec t or c omput ed t omography (MDCT ) ac quisit ion of images f or c alc ium sc oring. Disadv ant ages are t hat t his t y pe of gat ing is v ery sensit iv e t o c ardiac mot ion art if ac t s and image misregist rat ion. T his is espec ially t rue in pat ient s w it h arrhy t hmias. Wit h ret rospec t iv e ECG- gat ing, raw dat a are ac quired using t he spiral mode at a v ery low pit c h. At t he same t ime t he pat ient 's ECG is rec orded. Using t he ECG t rac ing, images c an be rec onst ruc t ed t o c reat e image st ac ks at any desired P.668

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1452

9 - Heart and Pericardium phase of t he c ardiac c y c le (F ig. 9- 2). Bec ause of t he low pit c h and dat a ov ersampling, dat a are av ailable along t he ent ire R- R int erv al (89). T hus,

images c an be rec onst ruc t ed at 5% t o 10% int erv als t o be used t o c reat e c ine loops. T his is somet imes t ermed “ f our- dimensional imaging” of t he heart . In addit ion, as lef t and right c oronary art ery mot ion is not sy nc hronous, images c an be inspec t ed t o det ermine t he point in t he dat a ac quisit ion ov er t he R- R int erv al w here mot ion is t he least f or eac h v essel. As a rule of t humb, image rec onst ruc t ion f or c oronary images is usually perf ormed at 60% t o 65% of t he c ardiac c y c le. How ev er, it may be t hat f or t he lef t c oronary sy st em t he least mot ion oc c urs in diast ole, w hile t he right c oronary art ery may hav e t he least mot ion during end sy st ole, espec ially in heart rat es abov e 70 beat s per minut e (bpm) (13).

F igure 9- 1 Wit h prospec t iv e ECG t riggering, a sequent ial CT sc an is st art ed at a predef ined point w it hin t he c ardiac c y c le. T hereaf t er t he t able mov es t o t he next posit ion, and t he proc edure is repeat ed unt il t he ent ire examinat ion v olume is c ov ered. CT , c omput ed t omography ; ECG, elec t roc ardiogram. (F rom Mahnken AH, Wildberger JE, Koos R, et al. Mult islic e spiral c omput ed t omography of t he heart : t ec hnique, c urrent applic at ions, and perspec t iv e. Car diov asc Int er v ent Radiol. 2005;28:388–399, w it h kind permission f rom Springer Sc ienc e and Business Media.)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1453

9 - Heart and Pericardium

F igure 9- 2 F or ret rospec t iv e ECG gat ing, a spiral MSCT sc an at low pit c h is perf ormed w hile t he pat ient 's ECG is rec orded simult aneously . During eac h c ardiac c y c le, an image st ac k is rec onst ruc t ed at dif f erent z- axis posit ions c ov ering a small part of t he heart (gray boxes). T he c ombinat ion of t he image st ac ks f rom all RR int erv als result s in a 3D dat a set of t he ent ire heart . ECG, elec t roc ardiogram; MSCT , mult islic e spiral c omput ed t omography . (F rom Mahnken AH, Wildberger JE, Koos R, et al. Mult islic e spiral c omput ed t omography of t he heart : t ec hnique, c urrent applic at ions, and perspec t iv e. Car diov asc Int er v ent Radiol. 2005;28:388–399, w it h kind permission f rom Springer Sc ienc e and Business Media)

T o dec rease c ardiac mot ion, imaging at a heart rat e of less t han 65 bpm is pref erable. As a result , int rav enous (5 t o 10 mg, met oprolol IV at t he t ime of t he examinat ion) or oral (50 t o 100 mg, met oprolol t art rat e by mout h 30 minut es bef ore imaging) bet a- bloc kers are rout inely administ ered if t he pat ient 's heart rat e is great er t han 65 bpm. It is import ant t o c hec k t he pat ient 's blood pressure prior t o bet a- bloc ker administ rat ion and again af t er t he examinat ion, bef ore t he pat ient leav es t he depart ment , t o ensure t hat t he pat ient is not hy pot ensiv e. Ot her c ont raindic at ions t o t he administ rat ion of bet a- bloc kers inc lude sev ere aort ic st enosis, Mobit z t y pe II or t hird- degree heart bloc k, and ac t iv e ast hma (12).

Temporal Resolution T emporal resolut ion of ECG- gat ed c ardiac CT st udies v aries w it h bot h heart rat e and gant ry rot at ion t ime. Gant ry rot at ion speeds of 330 msec rot at ion are

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1454

9 - Heart and Pericardium now possible on 64- det ec t or sy st ems, an improv ement f rom t he 500 msec /rot at ion speeds of 4- det ec t or sc anners. T hese higher gant ry rot at ion speeds permit t emporal resolut ion of 80 t o 100 ms (43). While EBT st ill has bet t er t emporal resolut ion (50 t o 100 ms), MDCT maint ains bet t er image qualit y w it h respec t t o spat ial resolut ion and image noise (2,12).

Wit h ret rospec t iv ely gat ed MDCT dat a, if t he pit c h of t he ac quired dat a is low enough, t emporal resolut ion c an be improv ed by rec onst ruc t ing image dat a f rom t w o t o f our c ardiac segment s (40). T his t ec hnique c an be used in pat ient s w it h f ast er heart rat es t o help dec rease c ardiac mot ion, and some manuf c t urers hav e inc orporat ed t his t ec hnology int o t heir 64- det ec t or sc anners.

Spatial Resolution Spat ial resolut ion of v olumet ric MDCT is, in it s best c ase, 0.4 Г— 0.4 Г— 0.4 mm3, w hereas t he resolut ion of c onv ent ional x- ray angiography is on t he order of 0.2 Г— 0.2 mm3 (12,41). Bec ause c oronary art eries are 3 t o 4 mm in diamet er proximally and 1 t o 2 mm in diamet er dist ally , some researc hers and c linic ians hav e sought t o inc rease t he size of t he c oronary art ery diamet er t ransient ly during CT sc anning v ia t he administ rat ion of 0.4 mg sublingual nit rogly c erin giv en 1 minut e prior t o sc anning (114). If t his is done, blood pressure should be monit ored c aref ully , espec ially if a bet a- bloc ker is administ ered c onc omit ant ly .

Protocols Prot oc ols f or CT c ardiac imaging depend on bot h t he t y pe of sc anner used and t he indic at ion f or imaging (T able 9- 1). TABLE 9- 1 C ARDIAC MDC T SC AN PROTOC OLS (E. G. SIEMENS SENSATION 16/64, F ORC HHEIM, GERMANY )

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1455

9 - Heart and Pericardium Non C orona ry EC G- ga te d (i. e . , c onge nita l, pe ric a rdia l) 16 Г— 64 Г— 1.5 .6

C a lc ium Sc oring C orona ry C TA Collimat i 16 × 64 × 16 × 64 × on (mm) 0.75 1.2 0.75 0.6 * Gant ry 375 375 375 330 375 375 rot at ion (msec ) F eed — — 3.0 3.8 5.4 7.7 per rot (mm) EKG Pro Pro Ret ro Ret ro Ret ro Ret ro gat ing Slic e 3 3 1 .75 1–3 0.75– t hic knes 3 s (mm) Inc reme 1.5 1.5 .5 .4 0.7–3 0.5–3 nt (mm) Ef f ec t iv 60 60 550 770 500 500 e mAs* * kVp 120 120 120 120 120 120 Sc an — — 5 5 5 5 delay (sec ) Cont ras — — 120 80 120 100 t (mL) Injec t io — — 4 4 4 4 n rat e (mL/sec ) * 64 = 32 det ec t ors w it h 2 f oc al spot s * * w ill depend upon pat ient size and t y pe of t ube av ailable Pro = prospec t iv e ECG t riggering Ret ro = ret rospec t iv e ECG gat ing P.669

Nonc orona ry Unga te d (pulmona ry v e ins) 16 Г— 64 Г— .75 0.6 500

375

12

5.5

None

None

1

1

1

1

140

180

120 5

120 5

120

100

4

4

C orona ry C ompute d Tomogra phic Angiogra phy . F or 64- slic e sy st ems, images are ac quired in spiral mode w it h 330 t o 350 ms rot at ion t ime and 64 Г— 0.6- 0.625 mm c ollimat ion (eit her 64 det ec t ors [General Elec t ric ] or 32 det ec t ors w it h double f oc al spot result ing in 64 slic es [Siemens]). T he t able inc rement is 3.8 t o 9.2 mm/rot at ion, also v ary ing by v endor. Ot her paramet ers inc lude pit c h 0.2, t ube v olt age 120 kVp, 750 t o 1,200 ef f ec t iv e mAs. Ef f ec t iv e mAs w ill v ary in degrees w it h bot h t he v endor and pat ient size, w it h great er mAs selec t ed f or heav ier pat ient s. Iodinat ed c ont rast agent is injec t ed at a rat e of 4 t o 5 mL per sec ond w it h t he lengt h of administ rat ion t ailored t o t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1456

9 - Heart and Pericardium lengt h of t he sc an. Alt hough some c ent ers injec t less c ont rast agent , at our c ent er an av erage 80 mL is injec t ed int rav enously f ollow ed by a 50 mL saline c haser (21). T his prov ides good opac if ic at ion of t he c oronary art eries w it h saline w ashout of c ont rast mat erial in t he superior v ena c av a and right v ent ric le. Pat ient s are inst ruc t ed in breat h holding, w it h a mean breat h- hold

durat ion f or t his ac quisit ion of 8 t o 12 sec onds. T he st art of image ac quisit ion is delay ed ac c ording t o t he prev iously det ermined c ont rast agent t ransit t ime, w hic h is done using eit her a t est dose or bolus t iming sof t w are, suc h as Smart Prep (General Elec t ric ) or CareBolus (Siemens). If bolus t iming sof t w are is used, t he region of int erest (ROI) f or t he program is plac ed in t he asc ending aort a at t he lev el of t he main pulmonary art ery (F ig. 9- 3). Image c onst ruc t ion is usually perf ormed at a “ sof t ” kernel suc h as B30f ; how ev er, if t he v essels are heav ily c alc if ied or t here are c oronary art ery st ent s in plac e, a sharper kernel suc h as B45f may be appropriat e (60). C a lcium Scoring. Calc ium sc oring rout inely has been perf ormed w it h prospec t iv e ECG- gat ing, t hat is, dat a are ac quired sequent ially ov er a 100- t o 200- millisec ond w indow presc ribed w it h a c ent er at 60% t o 65% of t he c ardiac c y c le. Radiat ion dose is low —less t han 1 mSv . Images are usually ac quired at 3- mm slic e t hic kness and rec onst ruc t ed at 1.5- mm inc rement s.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1457

9 - Heart and Pericardium F igure 9- 3 Preparat ion f or int rav enous c ont rast bolus f or c oronary CT angiography using bolus t iming sof t w are. T ransv erse image at lev el of

pulmonary art ery show s region of int erest (ROI, c irc le) in t he asc ending aort a.

P.670 Some aut hors hav e rec ent ly made an argument f or ac quiring t he dat a f or c alc ium sc oring w it h ret rospec t iv e rat her t han prospec t iv e ECG- gat ing (61). Alt hough t he radiat ion dose is higher (2 mSv ) f or dat a ac quired in t his f ashion, it has been show n t hat t here is less int erst udy v ariabilit y f or bot h Agat st on c alc ium sc ores and c alc ium v olume measurement s (61). Alt hough t his v ariabilit y may be import ant f or pat ient s undergoing c lose f ollow up ov er t ime, t he ac c urac y of sequent ial MDCT f or c oronary c alc ium quant if ic at ion is c onsidered suf f ic ient in most c ases f or st rat if ic at ion of pat ient risk (51). Noncorona ry EC G - G a te d C a rdia c Ima ging. Nonc oronary ECG- gat ed c ardiac imaging c an be used w hen broader c ov erage is required, as in assessment of t he heart f or c ongenit al or peric ardial disease or t umor. T he f eed/rot at ion is great er (and t he pit c h not as slow ) t o allow c ov erage in a single breat h- hold. T he ac quired slic e t hic kness is 2 mm, w it h rec onst ruc t ion inc rement at 1 mm, permit t ing adequat e v isibilit y of t he heart , great v essels, and surrounding st ruc t ures. At our inst it ut ion, t his essent ially is a gat ed pulmonary embolus (PE) prot oc ol. Giv en t hat c ongenit al heart lesions v ary , c ont rast enhanc ement may be t imed in eit hert he right or lef t heart . Know ledge of t he t y pe of image t o be imaged is import ant , as t hose w it h parallel pulmonary c irc uit ry (F ig. 9- 4) may require a split injec t ion, w it h c ont rast injec t ed v ia bot h t he ant ec ubit al and f emoral v eins. Pulmona ry Ve in Ima ging. Pulmonary v ein imaging, f or t he most part , is perf ormed w it hout ECG- gat ing, bec ause most of t hese st udies are perf ormed in pat ient s w it h at rial f ibrillat ion prior t o radiof requenc y ablat ion. Cont rast enhanc ement is t imed t o t he lef t at rium. Images are post proc essed using a shaded surf ac e display of t he lef t at rium t o demonst rat e anat omy (F ig. 9- 5), and mult iplanar rec onst ruc t ions (MPRs) of t he pulmonary v eins at t he ost ia are used t o prov ide measurement s of ost ial diamet er and dist anc e f rom t he ost ia t o t he f irst v ein branc h.

Radiation Dose and Methods of Reduction Alt hough t he radiat ion dose f or c alc ium sc oring is relat iv ely low , c oronary CT angiography met hods prov ide a radiat ion dose of 8 t o 10 mSv on 16- det ec t or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1458

9 - Heart and Pericardium sy st ems (130) and 14 t o 18 mSv on 64- det ec t or sy st ems. Met hods suc h as prospec t iv e t ube c urrent modulat ion c an dec rease t his dose on t he 64det ec t or sy st ems t o 7 t o 11 mSv (7,107). Pulse d- G a ting or Prospe ctiv e Tube C urre nt Modula tion. During

ret rospec t iv e ECG- gat ing, t he radiat ion exposure c an be signif ic ant ly reduc ed by presc ribing t ube c urrent modulat ion. Using t his t ec hnique, t he maximum mAs is employ ed only during a presc ribed period, usually a w indow of t ime c ent ered at 65% of t he c ardiac c y c le. T ube c urrent is reduc ed by 80% during t he remaining c ardiac c y c le. T his met hod c an reduc e t he radiat ion dose by 30% t o 50%, depending on t he heart rat e, but it is most ef f ec t iv e in pat ient s w hose heart rat es are slow er (12). On- Line Tube C urre nt Modula tion. Online t ube c urrent modulat ion adapt s t he mAs deliv ered during t he sc an based on pat ient t hic kness as det ermined f rom t he t opogram. Radiat ion dose reduc t ion has been desc ribed as bet w een 30% t o 50%, depending on t he body part imaged (49,62). Alt hough online t ube c urrent modulat ion use w it h ungat ed prot oc ols demonst rat es good result s w it hout c ompromising image qualit y (49,62), c are should be t aken w hen using t his met hod w it h ECG- gat ed prot oc ols, espec ially in c onc ert w it h prospec t iv e t ube c urrent modulat ion. T he v endor should be c onsult ed t o det ermine w het her it s c onc urrent use w it h ECG- gat ed prot oc ols w ill c reat e undue image noise.

Image Postprocessing and Interpretation Coronary CT angiograms perf ormed f or t he assessment of at herosc lerosis should be int erpret ed using a sof t w are pac kage t hat c an c reat e c urv ed MPRs of eac h c oronary art ery in t w o image planes lengt hw ise, along t he c ourse of t he c oronary art ery (89). A number of c ommerc ial sof t w are pac kages allow t hese c urv ed MPRs t o be c reat ed w it h relat iv e ease, c reat ing t he c urv ed MPRs using eit her edge det ec t ion or seed- grow ing t ec hniques. In addit ion, most hav e f unc t ions t hat permit measurement of perc ent st enosis diamet er. Bec ause of t he near- isot ropic v oxel size in 16- and 64- det ec t or MDCT , t hese MPRs maint ain an image qualit y t hat is similar in appearanc e t o t he axial images t hemselv es (89). T hree- dimensional v olume rendering and shaded surf ac e display may also be usef ul, more so in t he ov erv iew of c oronary art ery c ourse in t he assessment of anomalous c oronary art eries, or in prov iding an anat omic ov erv iew , how ev er, t han in t he assessment of at herosc lerot ic lesions.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1459

9 - Heart and Pericardium T hree- dimensional v olume rendering and shaded surf ac e display , on t he ot her

hand, c an play a key role in assessment and preoperat iv e planning f or v asc ular anomalies, suc h as anomalous pulmonary v enous ret urn, aort ic c oarc t at ion, or pulmonary art ery st enoses. T hey c an be usef ul in demonst rat ing c omplex c ongenit al anomalies. As ment ioned abov e, t hey also play a key role in demonst rat ing pulmonary v enous anat omy prec at het er radiof requenc y ablat ion. Also, as ment ioned prev iously , ret rospec t iv ely gat ed 3D dat a c an be rec onst ruc t ed at 5% t o 10% int erv als ov er t he c ardiac c y c le t o c reat e c ine loops. T hese loops, alt hough at a low er t emporal resolut ion t han MR, c an be used t o assess w all mot ion abnormalit ies, my oc ardial mass, ejec t ion f rac t ion, and v alv e mot ion (F ig. 9- 6).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1460

9 - Heart and Pericardium

F igure 9- 4 Pat ient w it h c omplex c ongenit al heart disease requiring bot h a Glenn shunt and F ont an proc edure. Init ial CT images (A, B) w it h c ont rast

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1461

9 - Heart and Pericardium injec t ed t hrough t he right ant ec ubit al only show t he Glenn shunt (ar r ow ) c onnec t ing t he superior v ena c av a (SVC) t o t he right pulmonary art ery . No c ont rast is ident if ied in t he F ont an (F ), lef t pulmonary art ery (ar r ow heads), or right at rium (RA), as t he SVC has been det ac hed f rom t he RA. An unsuspec t ing reader might int erpret t his as lef t pulmonary embolism or lef t pulmonary art ery t hrombosis. Af t er injec t ion of c ont rast t hrough t he right f emoral v ein (C , D, E), c ont rast is ident if ied in t he F ont an (F ) and lef t pulmonary art ery (ar r ow heads). T his f emorally injec t ed c ont rast has t rav eled f rom t he IVC t o t he RA and t hen t he F ont an. Mult iple c ollat erals are also not ed.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1462

9 - Heart and Pericardium

F igure 9- 5 Shaded surf ac e display images of t he lef t at rium (A, B) demonst rat e normal pulmonary v ein anat omy (lef t superior, lef t inf erior, right superior, right inf erior pulmonary v eins). Coronal MPRs (C t o F ) of t he ost ium of eac h v ein demonst rat e ost ial diamet er.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1463

9 - Heart and Pericardium

F igure 9- 6 F rames f rom a c ine MPR c reat ed in t he c oronal plane t hrough a prost het ic St . Jude's aort ic v alv e. F rames A and B are in sy st ole and f rame C in diast ole. F rames f rom t his c ine loop w ere made t o measure t he angle of t he leaf let s w hen open (A) and apposed (B).

P.671 P.672 P.673

Cardiac MR Unlike CT imaging of t he heart , t he c ardiac MR prot oc ol perf ormed is highly dependent on t he c linic al quest ion (110). F or inst anc e, t he prot oc ol f or assessing t he ext ent of my oc ardial inf arc t ion (MI) dif f ers great ly f rom t he prot oc ol f or assessing c oronary art eries or an int rac ardiac shunt . T hus, one must det ermine t he spec if ic reason f or t he perf ormanc e of t he examinat ion. Next , as is rout inely done, t he pat ient should be sc reened f or c ont raindic at ions t o t he MR examinat ion, suc h as t he presenc e of pac emakers, f erromagnet ic implant s, or int rac ranial aneury sm c lips (110). Unique t o t he c ardiac MR examinat ion, if pharmac ologic my oc ardial st ress agent s suc h as adenosine or dobut amine w ill be inc luded in t he prot oc ol, t he radiologist should also ask t he pat ient about relat iv e c ont raindic at ions t o t hese agent s. Cont raindic at ions t o adenosine inc lude ac t iv e bronc hospasm, f irst - degree heart bloc k, or sy st olic blood pressure of less t han 90 mm Hg (110). Also, pat ient s w ho are t o rec eiv e adenosine should not ingest c af f eine, c hoc olat e, or t heophy lline- c ont aining drugs 24 hours bef ore t he MR examinat ion, as t hese may inhibit t he ef f ec t iv eness of t he adenosine. Pat ient s should also be

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1464

9 - Heart and Pericardium inst ruc t ed t hat some of t he medic at ions giv en during t he examinat ion may make t hem f eel f lushed or nauseat ed.

Image Acquisition and Technique Cardiac Gating and Physiologic Monitoring In t he ac quisit ion of st at ic images, t o av oid image blur, MR image ac quisit ion must be limit ed t o a c onst ant port ion of t he c ardiac c y c le, usually end diast ole. T his is ac c omplished t hrough c ardiac gat ing. Gat ing c an be t riggered t o t he QRS c omplex of t he ECG or, alt ernat iv ely , t o a peripheral pulse. T he f ormer is t he most ef f ec t iv e (110). T he objec t iv e of ECG gat ing is t o ac quire a solid R w av e. T his R- w av e must be larger t han t he T or S w av e of t he ECG. Indeed, if t he T - w av e is muc h larger t han t he R- w av e, it is likely t hat t he elec t rodes hav e been plac ed t oo medially , and t he elec t rodes should be adjust ed. In addit ion, t he elec t rodes must maint ain good c ont ac t w it h t he skin. T o f ac ilit at e t his, shav ing t he skin may be nec essary . In addit ion, t he skin c an be c leaned w it h c ommerc ially av ailable abrasiv e agent s, and c oupling gels c an be used (110). Alt hough a st rong R- w av e may be present w hile t he pat ient is out side t he magnet bore, as t he pat ient ent ers t he magnet or af t er MRI has st art ed, addit ional noise c aused by t he magnet ic f ield and t he RF pulse may int erf ere w it h t he ECG t rac ing (110). T he use of new er f iberopt ic leads t o reduc e int erf erenc e or v ec t orc ardiography - based (VCG) t riggering t o improv e t he det ec t ion of t he R w av es c an reduc e t he number of misint erpret ed ECG ev ent s (124). Also on t he horizon is self - gat ed c ine imaging, w hic h uses t he v ary ing degrees of signal in t he blood pool t hroughout t he c ardiac c y c le as a leadless gat ing mec hanism (79). Phy siologic monit oring of pat ient heart rat e, blood pressure, and oxy genat ion is nec essary during many t y pes of c ardiac MR examinat ions. T his is espec ially t rue if t he examinat ion is being perf ormed f or assessment of c ardiac isc hemia or w hen adenosine or dobut amine is administ ered. MR- c ompat ible hemody namic monit oring sy st ems are now av ailable f or t his purpose.

Pulse Sequences In general, pulse sequenc es c urrent ly used f or c ardiac imaging c an be div ided int o dark blood and bright blood t ec hniques (110). In dark blood or blac k blood t ec hniques, f ast - f low ing blood is blac k or of low signal int ensit y . T hese

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1465

9 - Heart and Pericardium t ec hniques are most of t en used f or anat omic delineat ion inc luding, more

rec ent ly , t he assessment of v essel w alls and plaque (38,52). Examples of t his t ec hnique inc lude c onv ent ional spin ec ho (SE), breat h- hold t urbo or f ast - spin ec ho (T SE, F SE), and half - F ourier t urbo- spin ec ho sequenc es w it h doubleinv ersion rec ov ery (IR) pulses t o suppress blood signal (HAST E, double- IR T SE/F SE) (122). In general, dark blood sequenc es are prospec t iv ely gat ed; t hus, t he ef f ec t iv e (or t ot al) T R should be approximat ely 85% t o 90% of (or 100 msec less t han) t he pat ient 's R- R int erv al (t ime bet w een R w av es), plac ing dat a ac quisit ion in end- diast ole. F or inst anc e, t he ac t ual T R plus any t rigger delay (T D), if nec essary , w ill be approximat ely 85% t o 90% of t he R- R int erv al. Not e t hat f or T 1- w eight ing, T R should be less t han 900 ms. F or double IR sequenc es, w hic h are dark blood but T 2- w eight ed, t he T R should remain long and t he ac quisit ion w indow should c ov er t w o heart beat s (81,136). In bright blood t ec hniques, f low ing blood is w hit e or of high signal int ensit y . T hese are rout inely gradient - rec alled ec ho sequenc es (GRE). Cine GRE sequenc es t hat produc e a mot ion pic t ure loop t hroughout t he v arious phases of t he c ardiac c y c le are part ic ularly usef ul. Current ly GRE images c an be obt ained w it h segment ed k- spac e t ec hnique and c ardiac gat ing. A single- slic e mult iphase or mult islic e single c ardiac phase mode c an be perf ormed in a short breat h- hold period. Examples f or v arious v endors inc lude T urboF LASH (f ast low - angled shot ), f ast SPGR (spoiled gradient rec alled ec ho), and T F E/F F E (t urbo f ield ec ho/f ast f ield ec ho). T he paramet ers f or t hese sequenc es are adjust ed t o t he pat ient 's breat h- holding c apabilit y and heart rat e. F or pat ient s w it h P.674 slow er heart rat es, sequenc es t hat prov ide a great er number of lines per segment c an help t o short en t he required breat h- hold.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1466

9 - Heart and Pericardium

F igure 9- 7 Short - axis T rueF ISP (A) and st andard GRE (B) images demonst rat e t he bet t er c ont rast bet w een blood- pool and my oc ardium on T rueF ISP images in c omparison t o st andard GRE. T he bet t er CNR seen w it h T rueF ISP is an adv ant age w hen using segment at ion sof t w are f or f unc t ional analy sis of t he lef t v ent ric le.

New er f ast , short T E GRE sequenc es w it h c omplet ely ref oc used gradient s prov ide exc ellent c ont rast bet w een t he my oc ardium and blood pool and are c ommerc ially know n as T rueF ISP, balanc ed F F E, or F IEST A (F ig. 9- 7). Various t y pes of MR pulse sequenc es prov ide dif f erent inf ormat ion. F unc t ional abnormalit ies may not be examined direc t ly by dark blood t ec hniques but only inf erred by analy sis of result ant morphologic c hanges (18). F or example, aort ic regurgit at ion c an be inf erred f rom t he f indings of an enlarged lef t v ent ric le and dilat ed asc ending aort a. How ev er, a c ine bright blood t ec hnique w it h high t emporal resolut ion w ould allow f unc t ional analy sis, inc luding demonst rat ion of t he regurgit ant jet and quant if ic at ion of aort ic regurgit at ion. On t he ot her hand, most c ine ac quisit ions hav e low er c ont rast resolut ion result ing f rom t he short f lip angle and short T R employ ed. T he exc ept ions are t he c omplet ely ref oc used GRE sequenc es, w hic h prov ide exc ellent CNR. As a result , t hese T rueF ISP- t y pe sequenc es are v ery usef ul f or segment ing t he my oc ardium f rom t he blood pool and are exc ellent f or f unc t ional assessment of t he my oc ardium. Nev ert heless, remember t hat bec ause t he T E is so short in t hese sequenc es, less dephasing oc c urs, dec reasing t he v isibilit y of st enot ic or regurgit ant jet s. In addit ion, t hese sequenc es are less usef ul t han st andard GRE c ine sequenc es f or t he imaging of v alv e leaf let s (F ig. 9- 8) (106). T hus, st andard GRE sequenc es should be used in t he assessment of c ardiac v alv e leaf let s or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1467

9 - Heart and Pericardium w hen at t empt ing t o assess dif f ic ult - t o- ident if y int rac ardiac shunt s, inc luding at rial sept al or v ent ric ular sept al def ec t s. Cine sequenc es are now more c ommonly ret rospec t iv ely ECG- gat ed, w it h t he R- w av e used princ ipally as a t riggering dev ic e. Wit h t hese sequenc es t he

ac quisit ion w indow is set t o t he R- R int erv al or t o 100 ms great er t han t he RR int erv al, depending on t he t ec hnique and t he v endor. Ret rospec t iv e gat ing now applied t o t hese sequenc es prov ides t he benef it of imaging t he ent iret y of t he c ardiac c y c le, inc luding t he last 100 millisec onds. T his t y pe of ECGgat ing is part ic ularly usef ul in maint aining ac c urac y of measurement s c alc ulat ed f rom phase c ont rast c ine sequenc es. As a general rule, imaging should begin w it h dark blood sequenc es t o obt ain an ov erv iew and basic anat omic inf ormat ion and proc eed t o bright blood t ec hniques t o assess f unc t ional abnormalit ies.

Image Planes T he image planes as desc ribed in t his sec t ion, as t hey relat e t o image ac quisit ion, are princ ipally f or MR, bec ause MDCT is ac quired t ransaxially . How ev er, giv en t he abilit y of MDCT t o now ac quire in “ f our dimensions” (v olumet ric dat a ac quisit ion of t he heart t hroughout t he c ardiac c y c le, permit t ing t he c reat ion of c ine images), t he inf ormat ion in t he f ollow ing sec t ions c an also be used t o c reat e MDCT c ine images f rom t he v olumet ric dat a f or t he v isual assessment of w all and v alv e mot ion. Ut ilit y of t he c reat ion of c ine CT images in mult iple planes w ill likely improv e as t he t ec hnology and t emporal resolut ion do.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1468

9 - Heart and Pericardium

F igure 9- 8 Short - axis T rueF ISP (A) and st andard GRE (B) images t hrough t he aort ic v alv e plane demonst rat e bic uspid v alv e leaf let s. Alt hough T rueF ISP imaging prov ides a bet t er blood pool- t o- my oc ardium CNR in c omparison t o st andard GRE imaging, GRE imaging prov ides bet t er v isualizat ion of v alv e leaf let s.

P.675 T he planes generally used f or imaging t he t horax are t he t hree ort hogonal planes of t he t horax (t ransv erse, sagit t al, and c oronal) w it h t he pat ient supine. How ev er, as t he c ardiac axes are not parallel t o t he body axes, sec t ions parallel and ort hogonal t o c ardiac axes (short axis and long axis of t he heart ) are f av ored f or most c ardiac imaging (20,30,113). T hese hav e t he adv ant age of generally c orresponding t o t he planes used w it h ot her noninv asiv e c ardiac imaging modalit ies. T he MR examinat ion usually begins w it h a general anat omic surv ey using a dark blood t ec hnique in one or more of t he t hree planes: axial, c oronal, and sagit t al (110).

Scout Images: Transverse or Axial Plane T he axial imaging plane is t he imaging plane most f amiliar t o t he general radiologist . Most anat omic st ruc t ures are easy t o ident if y on t his plane, and t he ov erv iew permit s assessment of adjac ent t horac ic pat hology . T ransv erse or axial images (F ig. 9- 9) display t he normal relat ionships of t he great v essels and c ardiac c hambers. Port ions of t he proximal c oronary art eries near t heir origin and peric ardium c an also be display ed. Axial sec t ions are espec ially usef ul in ev aluat ing c ongenit al heart lesions and may c omplement morphologic ev aluat ion of pat ient s w it h ac quired heart disease.

Coronal and Sagittal Planes F or anat omic imaging, c oronal and sagit t al planes c an also be ac quired. T he c oronal plane (F ig. 9- 10) is of t en ef f ec t iv e f or demonst rat ing t he aort ic v alv e. More post eriorly , c oronal planes show t he ent ranc e of t he upper lobe pulmonary v eins int o t he lef t at rium. T he c oronal plane is also usef ul f or show ing t he diaphragmat ic surf ac e of t he lef t v ent ric le and t he ext ension of peric ardium ov er t he proximal port ion of t he great art eries. Double- oblique (oblique- sagit t al) planes t hrough t he pulmonary t runk and aort a (F ig. 9- 11) are usef ul f or demonst rat ing t he pulmonic and aort ic v alv es and out f low t rac t s. Ot her anat omy w ell seen on double- oblique images inc ludes t he c onnec t ions of t he superior and inf erior v ena c av ae t o right

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1469

9 - Heart and Pericardium at rium and one or more sinuses of Valsalv a. T he plane parallel t o t he axis of aort ic arc h, seen on axial P.676 images, is used t o obt ain oblique- sagit t al images f or ev aluat ion of aort ic dissec t ion (110).

F igure 9- 9 Axial T rueF ISP image t hrough t he heart demonst rat es t he lef t v ent ric le (LV), lef t at rium (LA), right v ent ric le (RV), and right at rium (RA).

F igure 9- 10 Coronal T rueF ISP image t hrough t he aort ic v alv e (ar r ow ) in diast ole. T his image also display s t he lef t v ent ric le (LV), right at rium (RA), superior v ena c av a (S), asc ending aort a (A), main pulmonary art ery (P), and a small port ion of t he right v ent ric le (RV).

Af t er obt aining any desired ort hogonal v iew s, many c ardiac MR st udies require images parallel t o t he t rue short and long axes of t he heart . Bec ause t he heart lies obliquely in t he t horac ic c av it y , t he t rue long axis of t he heart is orient ed approximat ely 45 degrees t o t he midsagit t al plane of t he t horac ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1470

9 - Heart and Pericardium spine. T hese short and long axis v iew s of t he heart are pref erred f or quant if ic at ion of v ent ric ular dimensions and regional c ont rac t ile f unc t ion

(20,113). Bec ause similar v iew s are obt ained during t he ECG, t hese planes are of t en f amiliar t o t he c ardiologist .

Vertical Long-Axis Plane (Two-Chamber View) T he v ert ic al long axis plane or t w o- c hamber v iew (F ig. 9- 12) is used t o ev aluat e t he lef t heart st ruc t ures. It rev eals inf ormat ion c onc erning superoinf erior and ant eropost erior P.677 anat omic relat ionships and is usef ul f or assessing t he mit ral v alv e. T his plane is presc ribed f rom an axial image t hat show s t he largest oblique diamet er of t he lef t v ent ric le (110).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1471

9 - Heart and Pericardium

F igure 9- 11 An oblique sagit t al or “ c andy c ane” image of t he aort a (B) c an be ac quired by presc ribing t he image f rom a t ransv erse image (A), w hic h demonst rat es t he asc ending aort a (AAo) and desc ending aort a (DAo). An oblique sagit t al image t hrough t he main pulmonary art ery (D) c an be ac quired by presc ribing t he image f rom a t ransv erse image (C ) t hat demonst rat es t he main pulmonary art ery (P).

F igure 9- 12 A t w o- c hamber or v ert ic al long- axis T rueF ISP image display s t he lef t v ent ric le (LV) and lef t at rium (LA). It also show s t he region of t he mit ral v alv e w ell (ar r ow ). Port ions of t he main pulmonary art ery (P) and aort ic arc h (A) c an also be ident if ied.

Horizontal Long-Axis Plane (Four-Chamber View) Images presc ribed f rom t he lef t v ent ric ular long axis (t w o- c hamber v iew ), set up t hrough t he post erior w all of t he lef t at rium, mit ral v alv e, and lef t v ent ric ular apex, prov ide a horizont al long axis or f our- c hamber v iew of t he heart (F ig. 9- 13). T he horizont al long axis plane or f our- c hamber v iew display s t he relat ionship of t he f our c ardiac c hambers t o eac h ot her on a single image. Cine GRE images obt ained in t his plane display mit ral, t ric uspid, and aort ic v alv e f unc t ion as w ell as right and lef t v ent ric ular c ont rac t ion. T his image plane c an also be obt ained by oblique t ransv erse imaging t hrough a short - axis sc out (110).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1472

9 - Heart and Pericardium

F igure 9- 13 A f our- c hamber or horizont al long- axis blac k- blood image show s t he lef t v ent ric le (LV), lef t at rium (LA), right v ent ric le (RV), and right at rium (RA). T his plane is ideal f or t he assessment of v ent ric ular or at rial sept al def ec t s and f or v isual assessment of t he t ric uspid and mit ral v alv es.

F igure 9- 14 Short - axis images suc h as t his are used f or t he assessment of lef t - v ent ric ular (LV) w all mot ion. T he right v ent ric le (RV) c an also be assessed. In t he LV, t he papillary musc les (ar r ow s) are also seen.

Short-Axis Plane T he short axis plane (F ig. 9- 14) is obt ained w hen images are presc ribed perpendic ular t o lef t v ent ric ular long axis seen on a t w o- c hamber v iew . It show s t he t rue c ross- sec t ional dimensions of c ardiac c hambers. Init ial images

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1473

9 - Heart and Pericardium in t his plane are perf ormed t hrough t he papillary musc les, w it h subsequent images perf ormed t ow ard t he heart apex and base. In t his plane t he lef t v ent ric ular my oc ardium is display ed as a doughnut - shaped ring. Cine GRE images allow v isualizat ion and quant if ic at ion of sy st olic my oc ardial w all t hic kening. T his plane c an also be used f or quant if y ing lef t and right

v ent ric ular v olume and mass, as w ell as v ent ric ular ejec t ion f rac t ion w hen t he appropriat e sof t w are is av ailable. Dif f erenc es bet w een right and lef t v ent ric ular st roke v olumes c an be used t o est imat e v alv ular regurgit at ion or shunt rat ios.

Aortic Outflow Long-Axis View T his v iew , obt ained t hrough t he lef t v ent ric ular apex and aort ic out f low t rac t , is presc ribed f rom a c oronal image (F ig. 9- 15). T his plane demonst rat es bot h t he aort ic and mit ral v alv es. As it display s port ions of t he lef t v ent ric le, right v ent ric le, lef t at rium, right at rium, and asc ending aort a, it is somet imes know n as t he f iv e- c hamber v iew .

F igure 9- 15 T he aort ic out f low long- axis v iew display s t he aort ic v alv e (long ar r ow ) and mit ral v alv e (shor t ar r ow s) simult aneously . T he lef t v ent ric le (LV), right v ent ric le (RV), lef t at rium (LA), and asc ending aort a (A) are also seen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1474

9 - Heart and Pericardium

F igure 9- 16 Cont rast - enhanc ed c oronary CT angiogram obt ained on a 16det ec t or sc anner. A: Mult iplanar rec onst ruc t ion (MPR) t hrough t he lef t main and lef t ant erior desc ending art ery show s sof t (nonc alc if ied) plaques (ar r ow s). B: MPR t hrough t he right c oronary art ery show s proximal art ery sof t and c alc if ied plaque. Calc if ied plaque is st able, w hile sof t plaque may be more prone t o rupt ure (C ). 3D surf ac e rendered image of t he heart on a sec ond pat ient w it h MPRs t hrough t he lef t ant erior desc ending art ery using a c ommerc ially av ailable v essel t rac king sy st em.

P.678

PERFORMANCE OF SPECIFIC TYPES OF EXAMINATIONS AND INTERPRETATION

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1475

9 - Heart and Pericardium Coronary Arteries and Coronary Atherosclerotic Disease Coronary CT Angiography Coronary art ery disease represent s a signif ic ant port ion of c ardiov asc ular disease, af f ec t ing 13.2 million Americ ans (6). It is also t he princ ipal c ause of mort alit y among Europeans age 65 and older (28). Coronary CT angiography ,

w it h it s quic k, noninv asiv e assessment , represent s an appealing alt ernat iv e t o c oronary x- ray angiography , part ic ularly in pat ient s w ho do not require int erv ent ion (F ig. 9- 16). Elec t ron- beam CT w as t he init ial modalit y used f or t he det ec t ion of st enot ic lesions and oc c lusions in t he proximal and middle segment s of c oronary art eries (4). Sensit iv it ies ranged f rom 74% t o 92% and spec if ic it ies f rom 66% t o 94% (4). One c onsist ent limit at ion w as t hat a subst ant ial number of c oronary art ery segment s c ould not be ev aluat ed f or st enosis bec ause of insuf f ic ient image qualit y (4). T his w as, in most c ases, c aused eit her by mot ion or sev ere c oronary c alc if ic at ions and af f ec t ed bet w een 11% and 28% of all c oronary segment s (4). P.679 Bec ause of it s modest t emporal resolut ion, and t hus ext ensiv e image blur, single- det ec t or spiral CT w as not c onsidered an opt imal modalit y f or c oronary art ery assessment . How ev er, MDCT sc anners, w it h t he improv ement in t emporal resolut ion, v olumet ric c ov erage, and t heir w idespread av ailabilit y , are now t he met hod of c hoic e f or c oronary CT imaging. At t he t ime t his c hapt er w as w rit t en, t here w ere only t hree st udies assessing c oronary imaging w it h 64- slic e MDCT (80,82,114). T he f irst (82) st udied 67 pat ient s w it h suspec t ed c oronary art ery disease (CAD) (47 w it h signif ic ant st enosis, 20 w it h no signif ic ant st enosis). No bet a- bloc kers, ot her t han t hose t he pat ient s w ere already t aking, w ere administ ered and t hus pat ient s had a heart rat e of 48 t o 90 (mean 66.3 В± 14.7) bpm. All c oronary segment s of 1.5 mm or great er in diamet er c ould be ev aluat ed by 64- slic e MDCT . Ov erall sensit iv it y , using inv asiv e c oronary angiography as t he ref erenc e st andard, w as 94%, spec if ic it y w as 97%, posit iv e predic t iv e v alue w as 87%, and negat iv e predic t iv e v alue w as 99%.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1476

9 - Heart and Pericardium T he sec ond (114) st udied 70 pat ient s undergoing elec t iv e inv asiv e c oronary angiography . Pat ient s w ere exc luded f or at rial f ibrillat ion. Pat ient s w it h heart rat es abov e 65 bpm rec eiv ed 100 mg of at enolol, w hic h allow ed 77% of t he

pat ient s t o hav e a heart rat e below 70 bpm. All c oronary art eries, ev en t hose 1.5 mm or less in diamet er, w ere assessed. Of 1,065 segment s, 935 (88%) c ould be ev aluat ed. Spec if ic it y , sensit iv it y , and posit iv e and negat iv e predic t iv e v alues f or t he presenc e of signif ic ant st enoses w ere: by segment (n = 935), 86%, 95%, 66%, and 98%, respec t iv ely ; by art ery (n = 279), 91%, 92%, 80%, and 97%, respec t iv ely ; by pat ient (n = 70), 95%, 90%, 93%, and 93%, respec t iv ely . T he t hird st udy (80) assessed 59 pat ient s undergoing x- ray angiography f or angina pec t oris. Of t hese pat ient s, 18 also underw ent int rav asc ular ult rasound (IVUS). Pat ient s w it h heart rat es great er t han 70 bpm w ere administ ered 50 mg of met oprolol, result ing in a mean heart rat e of 62 В± 13 bpm. Result s w ere slight ly less robust , w it h sensit iv it y f or less t han 50% diamet er st enosis at 79%; sensit iv it y f or great er t han 50% diamet er st enoses at 73%; and sensit iv it y f or great er t han 75% st enoses at 80%. Spec if ic it y f or all st enoses w as 97%. Compared w it h IVUS, 46 of 55 (84%) lesions w ere ident if ied c orrec t ly . T he mean plaque areas and t he perc ent age of v essel obst ruc t ion measured by IVUS and 64- slic e CT w ere 8.1 mm2 v ersus 7.3 mm2 (p 50% or в‰ Ґ50% n/N (% ) 55/55 (100) 71/71 (100) 70/70 (100) — 46/46 (100) 118/118 (100) 25/26 (96)

37/37 (100) 43/54 (80) 30/32 (94)

16/21 (76) — (97) — (97)

24/27 (89) 24/30 (80) 24/24 (100) 90/96 (94) 18/21 (86)

— — (85) 31/35(89) — (93) —

20/24 (83) 21/28 (75) 10/11 (91)

27/34 (79) — (98) — (95)

12/13 16/20 15/17 49/58 20/29

— — (93) 35/36 (97) — (96) —

(92) (80) (88) (84) (69)

© 2017 Enter your company name

1479

9 - Heart and Pericardium Nieman ′02 (48) Kuet t ner ′05 (54) Mart usc elli ′04

22/22 (100) 31/34 (91) 21/24 (88)

27/35 (77) — (99) — (100)

(56) Ropers (49) 17/18 (94) — Moon (51) 23/28 (82) — (94) Mollet ′05 (52) 17/18 (94) 31/32 (97) Mollet ′04 (53) 71/74 (96) — (94) Let a (55) 19/25 (76) — * Does not inc lude t ot al oc c lusion, †No dat a on sensit iv it y and spec if ic it y f or >70% st enoses n = number of st enoses det ec t ed w it h 16- slic e CT . N = number of st enoses det ec t ed w it h c oronary angiography .

2D Bre a th- Hold G ra die nt Echo Ima ging. In t he early 1990s segment at ion of k- spac e allow ed ac quisit ion of mult iple lines of dat a w it hin t he ECG- gat ed c ardiac c y c le (34). T his permit t ed 2D bright blood gradient - rec alled ec ho (GRE) sequenc es t hat c ould be c omplet ed in a single breat h- hold. In addit ion, spec t ral f at sat urat ion allow ed v isualizat ion of proximal c oronary art eries surrounded by epic ardial f at . Alt hough t he 2D GRE breat h- hold met hod has limit at ions—it is unable t o c ov er t he c ourse of a t ort uous c oronary art ery and t here is of t en slic e misregist rat ion—t he t ec hnique remains c linic ally usef ul and, f or some v endors, is t he princ ipal met hod av ailable f or c oronary art ery imaging. Adv ant ages t o t his met hod inc lude good signal- t o- noise rat io (SNR), quic k dat a ac quisit ion (10 t o 15 sec ond breat h- hold), and w idespread av ailabilit y . Eac h sequenc e prov ides a 5- t o 6- mm sec t ion of imaging. T he images are usually obt ained ort hogonal t o a prev iously obt ained 2D image of t he desired v essel (110).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1480

9 - Heart and Pericardium

F igure 9- 17 Non–c ont rast - enhanc ed images (A to D) f or c alc ium sc oring demonst rat e t he presenc e of c alc ium in t he right c oronary art ery (RCA), lef t c irc umf lex (LCx), and lef t ant erior desc ending (LAD) art eries.

3D Re spira tory - G a te d Me thods. T hese t ec hniques w ere dev eloped as researc hers sought t o ac quire a 3D dat a set of t he c oronary art eries (16,85,86). In 3D imaging, t hic k (2.5- t o 3.0- mm) slabs are ac quired and part it ioned int o t hin, c ont iguous slic es t hrough phase enc oding in t he t hird direc t ion. T his allow ed f or c ov erage of c onv olut ed art eries. Init ially , 3D GRE dat a c ould not be ac quired in a single breat h- hold. Apply ing a respirat ory gat ing nav igat or t ec hnique t o 3D sequenc es permit t ed f ree breat hing t hroughout dat a ac quisit ion, prov iding t he addit ional t ime nec essary t o ac quire a high- resolut ion (submillimet er, in- plane), high- SNR v olumet ric dat a set (110). Wit h respirat ory gat ing, a v ert ic al nav igat or spin ec ho is used t o monit or diaphragmat ic mot ion (F ig. 9- 18). T his is usually set at t he right hemidiaphragm, alt hough some users hav e plac ed it direc t ly on t he heart . F irst , a nav igat or sc out sequenc e is run t o det ermine t he loc at ion and exc ursion of t he diaphragm and t he point of end expirat ion. A 3- t o 5- mm “ ac c ept anc e w indow ” is t hen set around t his point of end- expirat ion. T oday t hese nav igat or met hods P.681

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1481

9 - Heart and Pericardium are usually c oupled w it h T rueF ISP sequenc es, bec ause of t he exc ellent c ont rast of t he c oronary art ery and v ent ric ular blood pool in c omparison t o my oc ardium and surrounding st ruc t ures (F ig. 9- 19). TABLE 9- 4 GUIDELINES F OR INTERPRETATION OF C ORONARY ARTERY

C ALC IUM SC ORE IN ASY MPTOMATIC PATIENTS AC C ORDING TO RUMBERGER ET AL. (63) Proba bility of Implic a tion C a lc ium Sc ore Signific a nt for C V Risk (Aga tston) Pla que Burde n C AD F a c tor 0 No ident if iable Very low Very low plaques 1–10 Minimal Very unlikely Low ident if iable plaque

Re c omme nda t ion Reassure pat ient Disc uss guidelines f or primary prev ent ion of CAD 11–100 Mild Mild or minimal Moderat e Counsel risk at herosc lerot ic c oronary f ac t or plaque st enosis likely modif ic at ion, exerc ise t est ing 101–400 Moderat e CAD highly Moderat ely Inst it ut e risk at herosc lerot ic likely high f ac t or plaque modif ic at ion, exerc ise t est ing >400 Ext ensiv e High likelihood High Aggressiv e risk at herosc lerot ic of signif ic ant f ac t or plaque burden c oronary modif ic at ion, st enosis exerc ise or pharmac ologic a l st ress t est 3D Bre a th- Hold Te chnique s. Bot h st andard GRE and T rueF ISP met hods c an

be used as breat h- hold t ec hniques. As t hey need t o be perf ormed in a single breat h- hold, t he spat ial resolut ion is low er t han f or respirat ory nav igat or c oupled met hods, but t hey are a quic k and easy mec hanism f or assessment of c oronary art ery c ourse and c an be used in anomalous c oronary art ery assessment .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1482

9 - Heart and Pericardium

F igure 9- 18 A: A v ert ic al spin ec ho is set at t he right hemidiaphragm. T his measures diaphragmat ic mot ion. B: Image demonst rat ing t he lung- liv er int erf ac e. T he bright line bet w een t he t w o represent s t he diaphragmat ic int erf ac e. Only lines of dat a c ollec t ed at end- expirat ion (ar r ow ) w ill be used f or image c onst ruc t ion.

Coronary Artery Disease Assessment T here hav e been mult iple small t rials t hat st udy c oronary MRA met hods f or t he assessment of signif ic ant (great er t han 50% diamet er) c oronary art ery st enoses. Result s, in general, hav e been v ariable f or all met hods. T w odimensional GRE breat h- hold sequenc es hav e y ielded sensit iv it ies of 63% t o 90% and spec if ic it ies of 37% t o 92% (31,90,105,109), and 3D GRE prospec t iv e nav igat or sequenc es hav e y ielded sensit iv it ies of 50% t o 100% and spec if ic it ies of 44% t o 100% (14,19,67,84,108,115). Variat ions in result s exist ev en among st udies using similar t ec hniques, likely bec ause of v ariabilit y in pat ient populat ion, P.682 imaging plat f orm, and t ec hnique implement at ion (27). One of t he largest st udies t o dat e assesses 3D GRE prospec t iv e nav igat or c oronary MRA, st udy ing 109 pat ient s (67). T his w as an int ernat ional, mult ic ent er t rial t hat used not only a c ommon imaging prot oc ol but also similar MR hardw are and sof t w are and similar rec ruit ment t ec hniques. In t his st udy , c oronary MRA had a high sensit iv it y and negat iv e predic t iv e v alue f or det ec t ing CAD in general, y et sensit iv it y and spec if ic it y f or indiv idual v essel disease w as modest . Alt hough t hese dat a suggest a limit ed c linic al role f or c oronary MRA in det ermining t he presenc e of mult if oc al disease, dat a using av ailable imaging

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1483

9 - Heart and Pericardium t ec hniques do not y et support c oronary MRA as a met hod sc reening f or CAD, or f or assessing c oronary art eries in pat ient s w it h c hest pain (27).

F igure 9- 19 T rueF ISP respirat ory nav igat or- gat ed images of t he RCA (A) and LAD (B). Wit h permission f rom ref erenc e 64.

Assessment of Myocardial Function and Wall Motion In t he Unit ed St at es, a large number of indiv iduals hav e an ECG w it hin day s bef ore t heir x- ray angiogram t o assess lef t v ent ric ular f unc t ion.

CT Assessment of Myocardial Function As t he c oronary CT angiogram is ret rospec t iv ely ECG gat ed (dat a is ac quired t hroughout t he c ardiac c y c le), dat a ac quired f or a c oronary CT angiogram c an also be used t o c reat e v olumet ric c ine images of t he heart . T hese c ine dat a c an t hen be used t o assess c ardiac f unc t ion. It is import ant t hat t he dat a required f or c ine imaging is already present in t he CT dat a ac quired f or t he c oronary CT angiogram and requires no repeat sc anning, inc rease in radiat ion dose, or administ rat ion of c ont rast agent . In addit ion, bec ause t hese dat a are v olumet ric , 2D mult iplanar rec onst ruc t ion (MPR) c ine images c an t hen be c reat ed at inc rement s t hroughout t he R- R int erv al in any sc an plan desired. Bec ause of t his, dat a ac quired during c oronary CT angiography c an be used t o

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1484

9 - Heart and Pericardium c reat e short - axis c ine images of t he lef t v ent ric le f rom t he c ardiac base t o apex suit able f or analy sis of lef t v ent ric ular f unc t ion (F ig. 9- 20) (140). T o dat e, researc hers (88) hav e demonst rat ed exc ellent c orrelat ion of LV

ejec t ion f rac t ion (EF ) c alc ulat ed by analy sis of short axis MPR c ine CT images t hrough t he heart t o LVEF c alc ulat ed by analy sis of mult iple short axis c ine MR images. F or t he last sev eral y ears, MR has been c onsidered t he gold st andard f or assessing lef t v ent ric ular f unc t ion (112). Researc hers hav e also demonst rat ed exc ellent c orrelat ion bet w een CT and MR f or end- diast olic v olume (EDV), end- sy st olic v olume (ESV), st roke v olume (SV), and my oc ardial mass. How ev er, t hey hav e not demonst rat ed good c orrelat ion of result s bet w een t he t w o modalit ies f or t ime- dependent c alc ulat ions (88), suc h as peak ejec t ion f rac t ion (PER) or peak f illing rat e (PF R). T his is, princ ipally , bec ause t emporal resolut ion f or bot h t he 64 and t he16- det ec t or ECG- gat ed c ardiac CT sc ans (85 t o 100 ms) are poorer in c omparison t o c ine c ardiac MR (30 t o 40 ms). As a result , CT imaging misses t he t rue peak v alues. It is ant ic ipat ed t hat adv anc es in CT imaging t hat improv e t emporal resolut ion w ould c orrec t t his problem.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1485

9 - Heart and Pericardium

F igure 9- 20 F rames f rom a short - axis c ine CT mult iplanar rec onst ruc t ion in (A) sy st ole and (B) diast ole. Images suc h as t hese c an be used f or f unc t ional assessment of t he lef t v ent ric le, alt hough t emporal resolut ion is less t han f or c ine MR imaging (C ). A f our- c hamber long- axis image has also been c reat ed. T hese c ine CT images c an be c reat ed f rom t he dat a ac quired f or c oronary CT angiography (D). T he short - axis c ine images c an t hen be ev aluat ed quant it at iv ely using c ommerc ially av ailable sof t w are.

P.683

MR Assessment of Myocardial Function (139) MRI T o assess w all mot ion t hroughout t he heart , c ont iguous short axis, bright blood, c ine images are obt ained f rom t he base of t he lef t v ent ric le t hrough t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1486

9 - Heart and Pericardium apex, beginning at t he lev el of t he mit ral v alv e. In addit ion, at least one horizont al long- axis image and a v ert ic al long- axis image are also obt ained. Init ially , st andard GRE sequenc es w ere used f or t his purpose. Current ly ,

how ev er, st eady - st at e f ree prec ession (SSF P) t ec hniques (T rueF ISP, balanc ed F F E, F IEST A) are used. T hese sequenc es hav e a subst ant ially higher blood pool t o my oc ardium c ont rast - t o- noise rat io (CNR) as c ompared w it h st andard GRE sequenc es. T his higher CNR result s in more ac c urat e aut omat ic blood- pool segment at ion (112,116) and more ac c urat e c alc ulat ion of lef t v ent ric ular (LVV) and ejec t ion f rac t ion (EF ). In addit ion, P.684 t he short er T R and T E result s in short er breat h- holds. When c oupled w it h parallel imaging met hods, breat h- holds f or c ine SSF P sequenc es are on t he order of 5 t o7 sec onds.

F igure 9- 21 Sat urat ion- t agged imaging c an be used f or quant it at iv e ev aluat ion of my oc ardial st ress and st rain.

My oc ardial t issue- t agged sequenc es (142), alt hough st ill usef ul f or c alc ulat ion of LV st ress and st rain, are more likely t o be used in researc h and are less usef ul c linic ally . T hese are GRE sequenc es w it h a series of sat urat ion bands in a grid f ormat c reat ed by radiof requenc y (RF ) pulses at t he onset of image ac quisit ion. Observ ing t he def ormat ion and lac k of def ormat ion of t he t ags t hroughout t he my oc ardium, one c an assess regions of w all mot ion abnormalit y (F ig. 9- 21). T his grid, how ev er, f ades during t he lat er part of t he c ardiac c y c le, alt hough t ec hniques hav e been dev eloped t o improv e t his disadv ant age (39,55), and blood pool t o my oc ardium c ont rast - t o- noise rat io (CNR) is poor.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1487

9 - Heart and Pericardium Quant it at iv e analy sis of t he t ags has also been relat iv ely c umbersome, alt hough rec ent researc h has been perf ormed w it h harmonic phase met hods (HARP, f ast HARP) t hat permit f ast er dat a ac quisit ion and more rapid analy sis of t agged MR images (74,103).

Stress Protocols Ische mia Asse ssme nt. Alt hough MR- c ompat ible exerc ise equipment exit s, it is dif f ic ult f or a pat ient t o exerc ise w it hin an MR sc anner. Bec ause of t his, pharmac ologic ally induc ed st ress is t he met hod of c hoic e. T here are t w o t y pes of pharmac ologic st ress agent s: v asodilat ors (suc h as adenosine or dipy ridamole) and bet a- agonist s (suc h as dobut amine). Vasodilat ors c ause het erogeneit y of my oc ardial f low , t hereby produc ing isc hemia. T hey produc e lit t le in t he w ay of w all- mot ion abnormalit ies. T hese agent s are c ommonly used in my oc ardial perf usion imaging. T he ef f ec t s of dobut amine, how ev er, are similar t o t hose of exerc ise, leading t o regional isc hemia, t ac hy c ardia, and inc reased my oc ardial c ont rac t ilit y . F or st ress w all- mot ion st udies, dobut amine is t he agent of c hoic e. T he prot oc ol used f or MRI is t he same as t hat used f or dobut amine ec hoc ardiography (T able 9- 5). Administ rat ion of t his agent requires c aref ul pat ient monit oring by a phy sic ian f or isc hemic sy mpt oms, w allmot ion abnormalit ies, and arrhy t hmias. Blood pressure must be monit ored and ECG t rac ings assessed bef ore and af t er dobut amine administ rat ion f or c hanges of isc hemia, suc h as ST depression, elev at ion, or T - w av e inv ersion. Cont raindic at ions t o dobut amine inc lude unst able angina, sev ere aort ic st enosis, art erial hy pert ension great er t han or equal t o 220/120 mm Hg, c omplex arrhy t hmias, hy pert rophic obst ruc t iv e c ardiomy opat hies, and my oc ardit is (112). Rev ersal of t he ef f ec t s of dobut amine c an be ac hiev ed using t he bet a- bloc ker esmolol 0.5 mg/Kg injec t ed int rav enously as a slow bolus (112). When dobut amine is administ ered, a f ully st oc ked c rash c art and c ardiac def ibrillat or should be av ailable. TABLE 9- 5 STRESS PROTOC OLS

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1488

9 - Heart and Pericardium Stre ss Te st Dobut amine f or t he det ec t ion of CAD

Dobut amine f or v iabilit y Adenosine

Protoc ol 5, 10, 20, 30, 40 Вµg/kg BW per minut e f or t hree minut es eac h В± up t o 1 mg at ropine at 40 Вµg/kg BW lev el unt il submaximal heart rat e is reac hed [(220- age) Г— 0.85] (half - lif e 2 minut es) Dobut amine IV 5, 10 Вµg/kg BW per minut e f or 3 minut es eac h. 140 Вµg/kg BW per minut e f or t hree minut es plus durat ion of MR sc an (half - lif e 10 sec onds).

BW = body w eight

Via bility Asse ssme nt. Low - dose dobut amine c ine c ardiac MRI examinat ions hav e been demonst rat ed as a reliable means of det ermining c ardiac v iabilit y (9) and assessing c ont rac t ile reserv e. A maximum of 10 Вµg/kg/minut e of dobut amine is inf used int rav enously (see T able 9- 5) (129). Rest and st ress images are t hen c ompared side by side f or segment al rec ov ery of w all t hic kening during sy st ole in my oc ardial regions t hat are dy sf unc t ional at rest (129).

Image Interpretation T o int erpret st ress dobut amine images, c ine loops at dif f erent dobut amine st ress lev els are v iew ed side by side. As t he dobut amine dose inc reases, t he images are assessed f or P.685 regions of lac k of inc rease in sy st olic w all t hic kening and/or new w all mot ion abnormalit ies in c omparison t o t he low er dobut amine dose. Onc e a w all mot ion abnormalit y is ident if ied, t he st udy st ops and t he next inc rement in dobut amine dose is not giv en.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1489

9 - Heart and Pericardium

F igure 9- 22 Sat urat ion- t agged imaging c an be used f or quant it at iv e ev aluat ion of my oc ardial st ress and st rain.

T he v ent ric le is usually assessed ac c ording t o an Americ an Heart Assoc iat ion 17- segment model (F ig. 9- 22) (112). At eac h st ress lev el, segment al w all mot ion is assessed as f ollow s: normokinet ic (1 point ), hy pokinet ic (2 point s), akinet ic (3 point s), or dy skinet ic (4 point s). T he sum of t hese point s is div ided by t he number of segment s t o y ield a w all mot ion sc ore. Normal c ont rac t ilit y result s in a w all mot ion sc ore of 1. Low - dose dobut amine (see T able 9- 5) is used t o assess f or t he presenc e of v iable my oc ardium. Wall t hic kness at end- sy st ole is assessed. T o assess f or v iable my oc ardium, one looks f or segment al improv ement in w all t hic kening or “ rec ov ery ” in regions of dy sf unc t ional my oc ardium at rest .

Calculation of LV Volumes and EF T here are many ac c urat e c ommerc ially av ailable sof t w are programs f or t he analy sis of LV v olumes, ejec t ion f rac t ion (EF ), and my oc ardial mass. Most of t hese sy st ems use t he modif ied Simpson rule (33) in t heir analy sis. T his st at es t hat t he v olume of an objec t c an be est imat ed by t aking t he sum of t he c ross- sec t ional areas of eac h sec t ion and mult iply ing by t he sec t ion t hic kness. T hus, most sof t w are sy st ems require a st ac k of short axis c ine images, and v olume is assessed at end- sy st ole (ES) and end- diast ole (ED); t he EF is c alc ulat ed as t he dif f erenc e of t he LV v olumes at ES and ED, div ided by t he LV v olume at ED. New er sof t w are pac kages make use of edge det ec t ion t o help w it h segment at ion along t he blood- pool- my oc ardial int erf ac e (F ig. 923). All, how ev er, require some user inv olv ement t o c hec k f or ac c urac y . Some hav e quest ioned w het her t o inc lude papillary musc les as blood pool or as

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1490

9 - Heart and Pericardium my oc ardium. T he c onsensus is t hat papillary musc les may be inc luded as eit her, as long as t he segment at ion is c onsist ent f or bot h diast olic and sy st olic LV analy sis. Inc luding t hem in t he blood pool, how ev er, appears t o assist w it h c onsist enc y of segment at ion.

F igure 9- 23 Int erf ac e of c ommerc ially av ailable sof t w are f or segment at ion of c ardiac blood pool f rom my oc ardium. T he sof t w are enables c alc ulat ion of lef t and right v ent ric ular f unc t ional paramet ers, inc luding st roke v olume, ejec t ion f rac t ion, my oc ardial mass, and w all t hic kening. Court esy of Gary Mc Neal and Jef f rey Bundy , Siemens Medic al Solut ions, Malv ern, PA.

My oc ardial mass c an be c alc ulat ed by most sof t w are sy st ems using t he same met hod, w it h my oc ardial v olume mult iplied by t he densit y of my oc ardium (1.05 gm/mL) (141). A less ac c urat e met hod f or assessing EF assumes t hat t he LV is an ellipse. T his is adapt ed f rom ec hoc ardiography . Using a single, horizont al long- axis (f our- c hamber) image, t he area (A) of t he LV endoc ardial border c an be t rac ed, and t he lengt h (L) of t he LV f rom t he mit ral v alv e t o t he apex c an be

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1491

9 - Heart and Pericardium measured. An est imat e of t he v olume c an t hen be c alc ulat ed f rom t he f ollow ing equat ion: Volume = 0.85(A 2/L) (112).

Viable and Nonviable Myocardium: Perfusion and Delayed Contrast Enhancement MRI My oc ardial perf usion st udies are perf ormed using f irst - pass my oc ardial gradient rec alled ec ho sequenc es c apable of rapidly est ablishing T 1 c ont rast f or mult iple slic es w it h high t emporal resolut ion (111). Rapid administ rat ion of a 0.05 t o 0.1 mmol/Kg dose of IV gadolinium, t o prov ide a t ight bolus (on t he order of 5 t o 8 mL/sec ond) is administ ered at rest and during pharmac ologic st ress (IV inf usion of adenosine) (see T able 9- 5). Depending on t he R- R int erv al and w het her or not parallel imaging is used, 3- t o 5- slic e posit ions c an be obt ained ov er mult iple phases, demonst rat ing low signal areas of underperf usion in t he P.686 my oc ardium. T hese low - signal areas c orrespond w it h regions of eit her isc hemia or inf arc t (F ig. 9- 24) at st ress and w it h regions of inf arc t at rest . Of import anc e is t hat t he adenosine must be administ ered v ia an IV c annula separat e f rom t he IV c annula used f or t he gadolinium- based c ont rast agent , as t he rapid bolus of c ont rast agent w ould push any remaining adenosine lef t in t he line int o t he v enous sy st em at t he same rat e, c ausing a risk of c omplet e heart bloc k. Adenosine is relat iv ely short ac t ing (half - lif e of 2 t o 10 sec onds), and t he c ardiac ef f ec t s of adenosine usually c an be rev ersed by merely st opping t he inf usion. Rev ersal of t he ef f ec t s of adenosine c an also be ac hiev ed by using 75 mg aminophy lline injec t ed int rav enously , as a slow bolus. Cont raindic at ions t o t he administ rat ion of adenosine inc lude unst able angina, sev ere art erial hy pert ension, ast hma or sev ere obst ruc t iv e pulmonary disease, and at riov ent ric ular bloc k (112). In addit ion, t he pat ient should be inst ruc t ed not t o t ake any medic at ion or f ood c ont aining aminophy lline or xant hines, inc luding c of f ee, t ea, c oc oa, and c ola, f or 24 hours bef ore t he st udy , bec ause t hese c an hinder t he ef f ec t iv eness of t he adenosine (112).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1492

9 - Heart and Pericardium

F igure 9- 24 A: F irst - pass perf usion image using adenosine pharmac ologic st ress demonst rat es a subendoc ardial perf usion def ic it in t he post erior lef t v ent ric ular w all (blac k ar r ow s). B: Subsequent delay ed c ont rast - enhanc ed imaging in t he same pat ient show s delay ed c ont rast enhanc ement in t he same region (w hit e ar r ow s), w hic h indic at es t hat t he perf usion def ic it is MI. C : In a sec ond pat ient , a post ero- sept al def ic it is ident if ied during f irst - pass perf usion imaging at pharmac ologic st ress. D: Delay ed c ont rast - enhanc ed imaging on t he same pat ient show s a muc h smaller region of enhanc ement , suggest ing t hat t he perf usion def ic it represent s princ ipally isc hemia.

Af t er administ rat ion of addit ional c ont rast agent t o reac h a t ot al of 0.2 mmol/Kg, single- slic e inv ersion rec ov ery (IR)- prepped T 1- w eight ed GRE sequenc es or new er 3D IR- prepped 3D GRE or T rueF ISP sequenc es c an be used in a delay ed f ashion (10 t o 15 minut es af t er t ot al c ont rast dose administ rat ion) t o demonst rat e regions of my oc ardial inf arc t ion or f ibrous t issue enhanc ement (65,66). T o obt ain opt imal CNR bet w een t he enhanc ed my oc ardial inf arc t ion and normal my oc ardium, t he IR pulse must be set t o null t he normal my oc ardium. T his c an be done v ia t rial and error or by using IR sc out sequenc es made av ailable by some v endors, w hic h allow one t o selec t t he most appropriat e IR t ime just bef ore delay ed c ont rast - enhanc ed image ac quisit ion. Phase- sensit iv e IR is an addit ional met hod t hat is less sensit iv e t o t he IR pulse set t ing. Phase- sensit iv e det ec t ion is used t o remov e t he bac kground phase w hile preserv ing t he sign of t he desired magnet izat ion during IR, t hus allow ing a more nominal IR t ime t o be selec t ed (64). By delay ed c ont rast - enhanc ed met hods, inf arc t ed my oc ardial t issue is demonst rat ed t o be eit her subendoc ardial (as in a non–Q- w av e MI) or t ransmural (F ig. 9- 25). Researc hers hav e demonst rat ed t hat t he appearanc e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1493

9 - Heart and Pericardium of t he inf arc t ed my oc ardial t issue c an predic t f unc t ional rec ov ery of t he my oc ardium af t er reperf usion. My oc ardial segment s c ont aining subendoc ardial inf arc t ion are more likely t o regain f unc t ion t han segment s w it h t ransmural inf arc t ion (25). In addit ion, on delay ed c ont rast - enhanc ed st udies, c ent ral hy poenhanc ement may at t imes be seen in larger inf arc t s. T his signif ies mic rov asc ular obst ruc t ion and has a w orse prognosis (24). Init ially t hought t o enhanc e only inf arc t ed my oc ardial t issue, delay ed c ont rast - enhanc ed met hods hav e prov en usef ul in t he diagnosis and assessment of ot her c ardiac disease ent it ies. T hese inc lude inf ilt rat iv e

proc esses, suc h as amy loid and c hronic c ardiac sarc oid. Viral my oc ardit is (F ig. 9- 26) also demonst rat es enhanc ement , as does t he f ibrous t issue in right v ent ric ular dy splasia (127).

CT Wit h t he dy namic c ont rast administ rat ion and t he f ast sc anning av ailable w it h MDCT , researc hers hav e been able t o ident if y my oc ardial perf usion def ec t s at rest in regions of MI (73,77). T here is some suggest ion t hat t his c ould be perf ormed during pharmac ologic st ress (77). At present , t he CT images are only suit able f or qualit at iv e analy sis, as t he t emporal resolut ion is insuf f ic ient t o prov ide ac c urat e quant it at iv e inf ormat ion. CT also has been used t o assess MI loc at ion and size using delay ed c ont rast enhanc ed met hods similar t o MRI (73,104). Delay ed imaging is perf ormed 5 t o 10 minut es af t er int rav enous iodinat ed c ont rast injec t ion (F ig. 9- 27) (73,104). While f urt her researc h needs t o be perf ormed c orrelat ing t his f inding w it h similar f indings on MRI, one st udy in pat ient s w it h reperf used MI has show n t hat a lat e def ec t surrounded by delay ed enhanc ement on CT may be indic at iv e of a residual perf usion SPECT def ec t (104).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1494

9 - Heart and Pericardium

F igure 9- 25 Delay ed c ont rast - enhanc ed imaging in t w o separat e pat ient s demonst rat es (A) t ransmural post ero- lat eral (ar r ow ) and (B) subendoc ardial post ero- sept al (ar r ow s) enhanc ement pat t erns. Subendoc ardial MIs are more likely t o demonst rat e w all- mot ion rec ov ery af t er rev asc ularizat ion.

P.687

CT and MRI of Other Cardiac Disease Nonisc hemic reasons f or a c ardiac CT or MRI examinat ion most f requent ly inc lude preoperat iv e and post operat iv e c ongenit al heart disease assessment , c linic al suspic ion of right v ent ric ular dy splasia, peric ardial disease (c onst ric t iv e peric ardit is v s. rest ric t iv e c ardiomy opat hy ), c ardiac t umors, anomalous c oronary art eries, and v alv ular disease. In t he f ollow ing sec t ion w e w ill disc uss and illust rat e eac h indic at ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1495

9 - Heart and Pericardium

F igure 9- 26 Y oung man w it h c hest pain and elev at ed serum t roponin lev els (A, B). Delay ed c ont rast - enhanc ed horizont al long- axis images demonst rat e epic ardial enhanc ement (ar r ow s) suggest iv e of a my oc ardit is. On quest ioning, t he pat ient rev ealed t hat he had a rec ent episode of t he “ f lu.” Coxsac kie B v iral t it ers w ere posit iv e.

F igure 9- 27 Images obt ained in a 38- y ear- old man w it h inf erosept al MI. LV, lef t v ent ric le. Short - axis v iew obt ained w it h delay ed- phase CT show s lat e enhanc ement inv olv ing t he w hole t hic kness of t he inf erosept al my oc ardium (ar r ow s). Wit h permission f rom Paul JF , Wart ski M, Caussin C, et al. Lat e def ec t on delay ed c ont rast - enhanc ed mult i- det ec t or row CT sc ans in t he predic t ion of SPECT inf arc t size af t er reperf used ac ut e my oc ardial inf arc t ion: init ial experienc e. Radiology . 2005;236:485–489.

P.688

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1496

9 - Heart and Pericardium Congenital Heart Disease Wit h bet t er c ardiot horac ic surgic al t ec hniques and t ec hnologic adv anc es, many pediat ric pat ient s w it h c ongenit al heart disease surv iv e int o adult hood and present w it h sequelae of t heir surgeries and disease. T hese inc lude

pat ient s w it h t ransposit ion of great v essels (T GA) and pat ient s w it h t et ralogy of F allot (T OF ). Bot h c ardiac CT and MRI c an be used f or post operat iv e f ollow - up in t hese pat ient s t o assess f or oc c luded shunt s (Wat erst on, Glenn, and so on), obst ruc t ed baf f les, and st enot ic homograf t s. Cardiac CT and MRI c an also be used f or v isualizat ion of unt reat ed disease, suc h as: pat ent duc t us art eriosus, c oarc t at ion of aort a, at rial sept al def ec t s, rest ric t iv e v ent ric ulosept al def ec t (VSD), and anomalous pulmonary v eins. Cardiac MRI has t he added adv ant age of being able t o prov ide quant it at iv e inf ormat ion, suc h as shunt (Qp/Qs) rat ios, gradient inf ormat ion ac ross st enot ic baf f les, homograf t s and v alv es, or aort ic c oarc t at ions. It c an also assess regurgit ant f rac t ions of v alv es w it h insuf f ic ienc y . Unt il rec ent ly , MRI had t he adv ant age of being able t o prov ide f unc t ional inf ormat ion t hat CT c ould not prov ide. How ev er, t he higher t emporal resolut ion 3D dat a set s of MDCT permit t he c reat ion of c ine mult iplanar rec onst ruc t ions t hat may be usef ul in v alv e and w all- mot ion assessment . F or bot h CT and MRI, it is import ant t o know t he c linic al quest ion bef ore image analy sis and int erpret at ion. How ev er, w hile t he prot oc ol f or perf orming t he CT examinat ion f or pat ient s w it h c ongenit al heart disease is st andard, f or c ongenit al heart disease one should ident if y t he spec if ic c linic al quest ion, know t he anat omy of t he relev ant pat hology and c ardiac surgery , and be aw are of t he delay ed c omplic at ions t y pic al of t he perf ormed surgery bef ore t he perf ormanc e of t he examinat ion.

General MR Protocol for CHD T he f irst sequenc es obt ained are usually blac k blood sequenc es, suc h as HAST E (double IR F SE/T SE) or T SE/F SE T 1- w eight ed sequenc es. How ev er, bright blood sequenc es, suc h as sequent ial F LASH, F AST CARD, T rueF ISP, or F IEST A are essent ial f or demonst rat ing f unc t ional pat hology , and t hey may be nec essary t o v isualize some int rac ardiac shunt s. Cine sequenc es (GRE) should be done, at t he v ery least , t hrough t he area of suspec t ed pat hology . Ideally , depending on t he disease, a CHD prot oc ol w ould inc lude some t ransv erse imaging (i.e., t he blac k blood sc out ) t o assess t he great v essels (i.e.,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1497

9 - Heart and Pericardium

presenc e of a duplic at ed superior v ena c av a, sidedness of t he arc h) and f ourc hambered long axis blac k blood and c ine sequenc es. Cine sequenc es should t hen be perf ormed t hrough t he aort ic and pulmonic v alv e planes and t hrough any surgic ally c reat ed shunt s (e.g., F ont an, Wat erst on, Blaloc k- T aussigt o) t o assess f or pat enc y and st enoses. Cont rast - enhanc ed MR angiography c an be used t o assess peripheral pulmonary art ery st enoses, bronc hial c ollat erals (pulmonic at resia), or anomalous pulmonary v eins.

Contrast-Enhanced MRA In t he c ardiac MRI assessment of adult pat ient s w it h c ongenit al heart disease, c ont rast - enhanc ed MRA is usef ul f or ev aluat ing t he aort a, pulmonary art ery st enoses, c ollat erals, shunt s and so on (F ig. 9- 28). Cont rast - enhanc ed MRA is a short breat h- hold 3D GRE sequenc e w it h short T R and T E and f lip angle. No c ardiac gat ing is needed. It requires a t est - bolus injec t ion or bolus t rac king sy st em, suc h as CareBolus (Siemens Medic al Sy st ems, Erlangen, Germany ) or Smart Prep (GE Medic al Sy st ems, Milw aukee, WI), t o c alc ulat e t he c irc ulat ion t ime and obt ain images w it h maximum art erial enhanc ement . Injec t ion rat e is usually 2 mL per sec ond of 0.2 mmol/Kg. Gd- DT PA of a c ommerc ially av ailable MRI- c ompat ible pow er injec t or is required. Images are usually obt ained in a c oronal orient at ion, but t hey c an also be obt ained in an oblique- sagit t al orient at ion t o assess t he aort ic arc h. Bot h pre- and post c ont rast images are ac quired w it h t he prec ont rast image serv ing as a mask f or image subt rac t ion. Af t er image ac quisit ion, post proc essed 3D maximum int ensit y projec t ion (MIP) images c an be c reat ed. T hese MIP images should alw ay s be ev aluat ed t oget her w it h sourc e images t o av oid misdiagnoses sec ondary t o MIP- induc ed art if ac t s. New er sequenc es t hat allow near- real t ime assessment of dy namic administ rat ion of a gadolinium- based c ont rast bolus are now also av ailable. T hese sequenc es, alt hough by nec essit y of low er resolut ion t han non–realt ime sequenc es, are helpf ul in t he assessment of shunt s and f ist ulas (37).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1498

9 - Heart and Pericardium

F igure 9- 28 A 20- y ear- old f emale pat ient w it h hy pert ension, unresponsiv e t o medic at ion. Lat eral (A) and c oronal (B) v iew s of c ont rast - enhanc ed 3D MRA c learly show c oarc t at ion of desc ending aort a (ar r ow ) and ext ensiv e c ollat eral v essels.

P.689

Intracardiac Shunts T he anat omic loc at ion of int rac ardiac shunt s suc h as VSD or ASD c an be def init ely demonst rat ed by MRI. In assessing f or a small or rest ric t iv e VSD, at rial sept al def ec t (ASD) or pat ent f oramen ov ale GRE c ine sequenc es are v it al t o v isualize t he jet c aused by t urbulent f low . T he shunt may be missed if only blac k- blood anat omic imaging is obt ained. Of not e is t hat w it h CT imaging, it may be dif f ic ult t o disc ern w het her or not an ost ium sec undum ASD is present , bec ause of t he t hinness of t he membrane at t he f ossa ov alis. In addit ion, on CT , t he high injec t ion rat e of c ont rast int o t he right heart may be misleading, of t en c ausing a right - t o- lef t jet of c ont rast ac ross a lef t - t o- right shunt . Wit h MR, shunt (Qp/Qs) rat ios c an be c alc ulat ed by presc ribing a phase c ont rast sequenc e perpendic ular t o t he f low of bot h t he asc ending aort a and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1499

9 - Heart and Pericardium proximal main pulmonary art ery . Using t his dat a, right and lef t v ent ric ular

st roke v olumes c an be c alc ulat ed and c ompared and a rat io c alc ulat ed. A rat io of 1:2 or great er is c onsidered c linic ally signif ic ant .

Patent Ductus Arteriosus T he duc t us art eriosus is a normal t ubular st ruc t ure t hat c onnec t s t he underside of t he desc ending aort a just dist al t o t he origin of t he lef t subc lav ian art ery t o t he main or lef t pulmonary art ery just bey ond it s origin. T he duc t us usually c loses short ly af t er birt h. How ev er, it c an remain pat ent and oc c asionally c an present in t he adult pat ient . Cine GRE MRI sequenc es c an ev aluat e f or t he presenc e of PDA, or one c an use a c ont rast - enhanc ed GRE t ec hnique.

Transposition of Great Arteries (TGA) In D- loop t ransposit ion (F ig. 9- 29), t he anat omic relat ionship of great art eries is rev ersed. T he aort ic v alv e arises ant erior t o t he pulmonic v alv e. T he aort ic v alv e and aort a arise f rom t he right v ent ric le, w hic h is usually hy pert rophied. T he pulmonary v alv e and pulmonary art ery arise f rom t he lef t v ent ric le. In Lloop t ransposit ion, t he aort a is lef t sided and arises f rom t he right v ent ric le, w hic h may at t imes be rudiment ary . T he pulmonary art ery arises post eriorly and t o t he right of t he aort a f rom t he lef t v ent ric le (F ig. 9- 30). If t he t w o v ent ric les are w ell dev eloped and t here is no int erv ent ric ular c ommunic at ion, w e ref er t o t his ent it y as c ongenit ally c orrec t ed t ransposit ion of t he great v essels. How ev er, at t imes t here is a large VSD w it h a rudiment ary right v ent ric le underneat h t he aort a. T he great art eries are t ransposed and t he t w o v ent ric les are inv ert ed. Repair of D- T GA is c urrent ly perf ormed using an art erial sw it c h proc edure (Jat ene). Prev iously a Must ard or Senning baf f le proc edure w as used. In t he Must ard operat ion, t he int ra- at rial sept um is remov ed and bov ine peric ardium c reat es ant erior (sy st emic ) and post erior (pulmonary v enous) baf f les. Most of t en t he reason f or perf orming an MR exam in t hese pat ient s w ho hav e had a baf f le is ev aluat ion f or baf f le pat enc y , inc luding ev aluat ion f or possible st enoses t hat may dev elop at t he superior v ena c av a (SVC) as it ent ers t he superior limb of sy st emic baf f le, or at t he pulmonary v eins.

Tetralogy of Fallot (TOF)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1500

9 - Heart and Pericardium T he c lassic c omponent s of t et ralogy of F allot (T OF ) are a large v ent ric ular sept al def ec t (VSD), right v ent ric ular P.690 out f low t rac t obst ruc t ion, right v ent ric ular hy pert rophy , and ov erriding aort a (F ig. 9- 31). Complet e repair of T OF is ac hiev ed w it h VSD c losure and inf undibulec t omy . Bef ore c omplet e repair, some pat ient s undergo a palliat iv e shunt t o improv e pulmonary blood f low . Shunt s t hat hav e c ommonly been perf ormed inc lude t he Blaloc k- T aussig, Wat erst on, Pot t s, and Glenn

anast omosis. T he Blaloc k- T aussig shunt c onnec t s t he subc lav ian art ery t o t he pulmonary art ery . F or ev aluat ion of t his shunt w it h MRI, an oblique t ransv erse plane is obt ained. T he Wat erst on shunt c onnec t s t he asc ending aort a t o right pulmonary art ery (F ig. 9- 32). T he Pot t s shunt c onnec t s t he desc ending aort a and lef t P.691 P.692 pulmonary art ery . T he Wat erst on and Pot t s shunt s are best ev aluat ed w it h MRI in t ransv erse plane. T he Glenn shunt c onnec t s t he SVC t o t he right pulmonary art ery (F ig. 9- 33). T ransv erse or c oronal images in t he plane of t he SVC eit her ac quired by MRI or rec onst ruc t ed on 3D MDCT dat a set s are usef ul f or ev aluat ion of t his shunt .

F igure 9- 29 D- loop t ransposit ion of t he great art eries (A). T he asc ending aort a (AAo) arises ant erior and t o t he right of t he pulmonary art ery (P) (B). T his pat ient has had a Must ard baf f le operat ion, w hic h div ides t he at ria int o a pulmonary v enous (PV) c hamber and a sy st emic (S) c hamber. T his baf f le direc t s t he blood f rom t he SVC and IVC t o t he morphologic lef t v ent ric le (LV)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1501

9 - Heart and Pericardium and t hen t o t he pulmonary art eries. Oxy genat ed blood f rom t he lungs ent ers t he pulmonary v enous port ion of t he baf f le and is direc t ed t o t he right v ent ric le (RV) and out t he aort a.

F igure 9- 30 L- loop or “ c ongenit ally c orrec t ed” t ransposit ion of t he great art eries (A). T he asc ending aort a (AAo) arises ant erior and t o t he lef t of t he pulmonary art ery (P) (B). In L- loop t ransposit ion, t here is at riov ent ric ular disc ordanc e. T his pat ient also has a large v ent ric ulosept al def ec t (VSD). LV, lef t v ent ric le; RV, right v ent ric le; LA, lef t at rium.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1502

9 - Heart and Pericardium

F igure 9- 31 Pat ient w it h t et ralogy of F allot (T OF ) A: Post erior- ant erior c hest radiograph demonst rat es t he c lassic appearanc e of T OF . T he pat ient has a right - sided aort ic arc h and a boot - shaped heart . T his oc c urs bec ause of t he hy pert rophy of t he right v ent ric le, w hic h lif t s t he c ardiac apex upw ard. B: T ransv erse dark blood image demonst rat es t w o c omponent s of t he t et ralogy : a VSD (ar r ow ) and right v ent ric ular hy pert rophy . C : Cine T rueF ISP image t hrough t he pulmonary out f low t rac t show s inf undibular pulmonic st enosis (ar r ow ), w it h a jet of st enosis abov e t he narrow ing. D: A T rueF ISP image on

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1503

9 - Heart and Pericardium anot her pat ient demonst rat es a large VSD (ar r ow ) w it h ov erriding asc ending aort a (AAo).

F igure 9- 32 Axial c ine GRE image show s a st enot ic Wat erst on shunt (ar r ow ) in a pat ient w it h pulmonic at resia and hy poplast ic right v ent ric le. T he Wat erson shunt c onnec t s t he asc ending aort a t o t he right pulmonary art ery . Arrow s point t o a jet in right pulmonary art ery . Wit h permission f rom Poust c hiAmin M, Gut ierrez F R, Brow n JJ, et al. How t o plan and perf orm a c ardiac MR imaging examinat ion. Radiol Clin Nor t h Am . 2004;42:497–514.

Anomalous Pulmonary Veins MRI and CT are highly ac c urat e in t he diagnosis of part ial or t ot al anomalous pulmonary v enous c onnec t ion as w ell as sev eral ot her anomalies of t he v enous sy st em. An anomalous right upper lobe pulmonary v ein usually drains int o SVC and of t en is assoc iat ed w it h a sinus v enosus ASD. An anomalous lef t upper lobe pulmonary v ein may look like a duplic at ed SVC, but it c an be dif f erent iat ed f rom SVC duplic at ion by f ollow ing t he v essel bac k t o it s origin (F ig. 9- 34).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1504

9 - Heart and Pericardium

F igure 9- 33 Of f - axis c oronal image in a pat ient w it h c omplex c ongenit al heart disease show s a Glenn shunt (ar r ow s) c onnec t ing t he superior v ena c av a (S) t o t he right pulmonary art ery .

Pulmonary Vein Mapping (137) At rial f ibrillat ion is t he most c ommon arrhy t hmia and is present in up t o 5% of pat ient s aged 65 y ears and ov er (35). Perc ut aneous c at het er ablat ion, a met hod of t ransc at het er RF ablat ion or c ry oablat ion of arrhy t hmogenic f oc i, has rec ent ly dev eloped int o a c ommonly perf ormed t reat ment f or at rial f ibrillat ion. F irst desc ribed in 1994 (50), perc ut aneous c at het er ablat ion f or at rial f ibrillat ion has rapidly bec ome a minimally inv asiv e alt ernat iv e t o t he maze proc edure (t he surgic al met hod of int errupt ing elec t ric al pat hw ay s by c reat ion of lef t at rial sc ar t issue) and a more suc c essf ul alt ernat iv e t o c ardiov ersion. T hus, it is ant ic ipat ed t hat t he radiologist in prac t ic e w ill enc ount er request s t o assess pulmonary v enous anat omy bef ore t he proc edure or be c alled on t o perf orm CT or MRI t o assess a pat ient f or possible post proc edure c omplic at ions. Of princ ipal import anc e in preproc edure planning f or perc ut aneous c at het er ablat ion is ac c urat e ident if ic at ion of t he ost ia of t he main pulmonary v eins (PVs) (47,78). T his is espec ially helpf ul t o t he ref erring c ardiologist , as he or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1505

9 - Heart and Pericardium

she w ill need t o selec t iv ely c annulat e and elec t ric ally map eac h v essel ost ium t o dec ide w here t o perf orm ablat ion. Model anat omy is f ound in only 70% of c ases, w it h t he remaining 30% of indiv iduals hav ing pulmonary v enous anat omy v ariat ion relat ed t o under- or ov erinc orporat ion of t he c ommon PV int o t he lef t at rium during embry ologic dev elopment (47). Bec ause perc ut aneous c at het er ablat ion is perf ormed under f luorosc opy , prolonged radiat ion exposure is one of t he disadv ant ages t o perc ut aneous c at het er ablat ion (78). Det ailed know ledge about a spec if ic pat ient 's pulmonary v enous anat omy bef ore t he proc edure may short en t he lengt h of t he proc edure and dec rease t he f luorosc opy t ime t hat w ould ot herw ise be required t o ident if y eac h v essel. In addit ion, a “ road map” may prov ide a more f av orable out c ome, prev ent ing addit ional smaller ost ia f rom being missed as pot ent ial sourc es of arrhy t hmia. Also of import anc e is t he size of t he ost ia. T his is t rue not only f or selec t ion of c at het er size but also f or preproc edure ident if ic at ion of ac c essory v eins w it h small ost ia, w hic h are P.693 more likely t o dev elop st enoses. We also prov ide inf ormat ion regarding dist anc e f rom t he pulmonary v ein ost ium t o it s f irst branc h point . T his is part ic ularly import ant if t he v essel branc hes early .

F igure 9- 34 Pat ient w it h part ial anomalous pulmonary v enous ret urn (A, B). T he v ert ic al v ein (long ar r ow ) c an be mist aken f or a duplic at ed SVC (C , D).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1506

9 - Heart and Pericardium

How ev er, if f ollow ed, one c an see t hat t his leads t o t he anomalous lef t upperlobe pulmonary v ein (shor t ar r ow ). A duplic at ed SVC w ould drain int o t he c oronary sinus.

Radiologist s need t o be aw are of post ablat ion c omplic at ions. T hey need t o know of t hese c omplic at ions so as t o ident if y t hem w hen spec if ic ally asked t o perf orm CT or MRI af t er ablat ion; how ev er, t hey also need t o be aw are of post ablat ion c omplic at ions as possible c auses of nonspec if ic signs, sy mpt oms, and radiologic f indings w hen t he hist ory prov ided is less c lear. In t his w ay , t he c omplic at ion w ill not be missed. T he most c ommon c omplic at ion of perc ut aneous c at het er ablat ion is PV st enosis. In one st udy , 44% of pat ient s w it h PV st enosis af t er c at het er ablat ion present ed w it h short ness of breat h, c ough, or hemopt y sis (119). Pulmonary st enoses may dev elop up t o 8 mont hs af t er perc ut aneous c at het er ablat ion, w it h pat ient s present ing t o t heir int ernist or t o t he emergenc y depart ment some mont hs af t er t he proc edure. In one st udy , nonspec if ic respirat ory sy mpt oms along w it h imaging f indings init ially led t o erroneous radiologic diagnoses of pneumonia, pulmonary embolism, and lung c anc er (119). Chest radiography may demonst rat e f oc al pulmonary edema in bot h PV st enosis and t hrombosis, and t his c ould be int erpret ed as pneumonit is (47). Also, v ent ilat ion- perf usion sc anning in bot h ent it ies may demonst rat e a v ent ilat ion- perf usion mismat c h, mimic king pulmonary embolism. T hus, it is import ant f or t he radiologist t o c onsider c omplic at ions of perc ut aneous c at het er ablat ion t o seek t he appropriat e c linic al hist ory w hen int erpret ing t he images. MDCT and f ast MRA, allow noninv asiv e, high- resolut ion, 3D imaging of t he PVs and lef t at rium. T here are f ew noninv asiv e alt ernat iv es t o t hese t w o t ec hniques. T ransesophageal ec hoc ardiography c an be used but is moderat ely operat or dependent . Some c ardiologist s perf orm perc ut aneous c at het er ablat ion w it hout an init ial imaging examinat ion. T he argument s against a preproc edure imaging st udy mainly arise f rom t hose w ho believ e t hat a signif ic ant number of arrhy t hmogenic f oc i in at rial f ibrillat ion are not isolat ed t o t he PVs. Ot her indiv iduals believ e t hat bec ause t here is no opt imal t reat ment f or PV st enosis, preproc edure imaging is not w arrant ed. Nev ert heless, great er numbers of c ardiologist s are c hoosing t o perf orm CT , MRI, or bot h t o prov ide a P.694 road map and a baseline. Proponent s of preperc ut aneous c at het er ablat ion CT at our inst it ut ion hav e argued t hat , besides prov iding inf ormat ion about

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1507

9 - Heart and Pericardium pulmonary v enous anat omy , t he images c an serv e as a ref erenc e f or c omparison at f ollow up, should sy mpt oms lat er arise. One reason f or t his is

t hat some normal PVs hav e regions of narrow ing. A preproc edure imaging st udy allow s one t o det ermine w het her t he pulmonary v enous narrow ing ident if ied is normal f or t hat pat ient or iat rogenic .

Cardiomyopathies Cardiomy opat hies may be assessed by bot h MR and MDCT , alt hough MR has t he adv ant age at present of bot h bet t er t emporal and c ont rast resolut ion. Cine MR or CT images in t he short axis c an be used t o assess w all mot ion, ejec t ion f rac t ion, st roke v olume, and my oc ardial mass. Delay ed MR c ont rast enhanc ed imaging c an be used t o assess f or f ibrosis and some inf ilt rat iv e proc esses. In t heory , delay ed c ont rast - enhanc ed CT c ould also be used f or t his purpose; how ev er, t here has been lit t le experienc e w it h delay ed c ont rast enhanc ed CT , and t his has princ ipally been w it h MI. In MRI, c ine t ec hniques c an be used t o assess peak f illing rat es (PF R), w hic h c an be used as a measure of diast olic dy sf unc t ion (56). Delay ed c ont rast - enhanc ed MRI t ec hniques demonst rat e sept al enhanc ement in 75% of pat ient s w it h hy pert rophic c ardiomy opat hy (F ig. 9- 35) (128). T his usually oc c urs as pat c hy enhanc ement c onsist ent w it h t he plexif orm f ibrosis, w hic h is seen hist opat hologic ally in hy pert rophic pat ient s in c omparison t o t he massiv e f ibroses seen in pat ient s w it h MI, alt hough oc c asionally massiv e delay ed sept al c ont rast enhanc ement c an be seen as w ell (128). Amy loid is t he most c ommon of all inf ilt rat iv e rest ric t iv e c ardiomy opat hies in t he West ern w orld. Delay ed c ont rast - enhanc ed t ec hniques hav e rec ent ly been show n t o demonst rat e global subendoc ardial enhanc ement in pat ient s w it h c ardiac amy loidosis (F ig. 9- 36) (87). T his enhanc ement , by T 1 measurement s, w as most pronounc ed at 4 minut es. Af t er 8 minut es t his enhanc ement w as not observ ed. Also not ed w as rapid w ashout of gadolinium f rom t he blood pool and my oc ardium. T his has been hy pot hesized t o be sec ondary t o gadolinium dist ribut ion in t he t ot al body amy loid load (87).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1508

9 - Heart and Pericardium

F igure 9- 35 T y pes of delay ed c ont rast enhanc ement seen in pat ient s w it h HCM. A: Massiv e t y pe. B: Spot t y t y pe. Arrow show s delay ed c ont rast enhanc ement . Wit h permission f rom T eraoka K, Hirano M, Ookubo H, et al. Delay ed c ont rast enhanc ement of MRI in hy pert rophic c ardiomy opat hy . Magn Reson Im aging. 2004;22: 155–161.

F igure 9- 36 CMR in a pat ient w it h sy st emic AL amy loidosis. T op row show s diast olic f rames f rom c ines (v ert ic al long axis, horizont al long axis, and short axis, respec t iv ely ) show ing a t hic kened LV and pleural ef f usions (Pl ef f ) and peric ardial ef f usions (Pc ef f ) assoc iat ed w it h heart f ailure. Bot t om row show s lat e gadolinium enhanc ement images in t he same planes. T he CMR sequenc e f orc es my oc ardium remot e f rom t he pat hology t o be nulled (blac k), suc h t hat t he abnormal region is enhanc ed. In c ardiac amy loidosis, how ev er, t he region of great est abnormalit y is enhanc ed as t he ent ire my oc ardium is af f ec t ed w it h amy loid inf ilt rat ion, and t he result is dif f use global subendoc ardial enhanc ement (st r aight ar r ow s). T he endoc ardium of t he right v ent ric le (RV) is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1509

9 - Heart and Pericardium also heav ily loaded w it h amy loid; t heref ore, t he sept um in t he horizont al long

axis v iew show s biv ent ric ular subendoc ardial enhanc ement w it h a dark midw all (zebr a appear anc e; dot t ed ar r ow s). T he right v ent ric ular f ree w all is also enhanc ed (c ur v ed ar r ow ). Not e t hat t he blood pool is dark, w hic h does not oc c ur in ot her report ed c ondit ions, indic at ing abnormal gadolinium handling in t hese pat ient s. LA, lef t at rium; RA, right at rium. Wit h permission f rom Mac eira AM, Joshi J, Prasad S, et al. Cardiov asc ular magnet ic resonanc e in c ardiac amy loidosis. Cir c ulat ion. 2004;111:186–193.

Sarc oidosis also has been show n t o demonst rat e delay ed c ont rast enhanc ement in a punc t uat e or pat c hy dist ribut ion (98). While t radit ionally present ing as a rest ric t iv e c ardiomy opat hy , in c hronic st ages t he my oc ardium dev elop regions of t hinning w it h c orresponding w all mot ion abnormalit ies (F ig. 9- 37). T hese f oc i of enhanc ement c an be seen w it h or w it hout w all mot ion abnormalit y and, anec dot ally , appear t o c orrelat e w it h arrhy t hmogenic f oc i.

Right Ventricular Dysplasia One of t he more f requent and import ant indic at ions f or c ardiac MRI and, more rec ent ly , CT imaging, is t he ev aluat ion of pat ient s w it h pot ent ial diagnosis of arrhy t hmogenic right v ent ric ular dy splasia. T his c ondit ion is a primary disorder of t he right v ent ric le w it h part ial or t ot al t hinning and replac ement of musc le by adipose or f ibrous t issue and enlargement of t he right c hambers of t he heart . Pat ient s hav e v ent ric ular arrhy t hmias and lef t bundle branc h bloc k on ECG. T he disease may lead t o sudden deat h. RV dy splasia is f amilial in 30% of c ases. Inherit anc e pat t ern is possibly aut osomal dominant w it h v ariable expression and penet ranc e (10,26,44). Right v ent ric ular angiography and ec hoc ardiography c annot v isualize pat hologic st ruc t ural c hanges of RV dy splasia in t he my oc ardium. Ev en w it h endomy oc ardial biopsy t he diagnosis c an be dif f ic ult , as t he disease rarely inv olv es t he sept um, P.695 w hic h is t he t y pic al sampling sit e. Pat ient s are c ommonly ref erred f or c ardiac MR or oc c asionally CT imaging (17,135).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1510

9 - Heart and Pericardium

F igure 9- 37 45- y ear- old w oman w it h sarc oid and c ardiac arrhy t hmias. Vert ic al long axis (A) and short axis (B) delay ed c ont rast - enhanc ed images of t he heart show mult iple small enhanc ing lesions in t he post erior- sept al w all (ar r ow s), along w it h my oc ardial t hinning in t his region. When ac ut e, sarc oid c an present as an inf ilt rat iv e hy pert rophic c ardiomy opat hy . Chronic ally , how ev er, t he my oc ardium c an bec ome t hinned w it h delay ed enhanc ement demonst rat ing pat c hy or nodular enhanc ement .

MR diagnosis is based on t he ident if ic at ion of spec if ic anat omic and f unc t ional abnormalit ies of t he right v ent ric le, w hic h inc lude one or more of t he f ollow ing: t hinning of t he right v ent ric ular f ree w all, hy pert rophied t rabec ulat ion, inc reased my oc ardial signal int ensit y f rom f at t y replac ement , dec reased sy st olic w all t hic kening or mot ion (RV akinesis or dy skinesis) c ausing f oc al bulging at t he sit e of my oc ardial f ibrosis, right v ent ric ular out f low t rac t enlargement , diminished ejec t ion f rac t ion, and impaired v ent ric ular f illing in diast ole (126). T he right v ent ric le and at rium c an be normal in size or dilat ed. More rec ent ly , t he f ibrous c omponent s of t he f ibrof at t y inf ilt rat ion hav e been show n t o demonst rat e delay ed c ont rast enhanc ement (F ig. 9- 38) (127). MR ev aluat ion of right v ent ric ular dy splasia is ac hiev ed by using blac k blood breat h- hold sequenc es along w it h bright blood c ine imaging. Blac k blood imaging is obt ained in eit her t he long axis or t ransv erse image orient at ion, c ont iguous 5- mm slic es w it h no gap. Short - axis blac k- blood images are not required. Cine sequenc es t o mat c h t he loc at ion of t he blac k- blood images are v ery import ant t o assess f or areas of RV dy sf unc t ion (akinesis, dy skinesis, and f oc al bulge). T hese also may be perf ormed in t he short axis if quant it at iv e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1511

9 - Heart and Pericardium analy sis (st roke v olume, ejec t ion f rac t ion) of t he RV is request ed. Suc c essf ul

delay ed c ont rast - enhanc ed MRI has been perf ormed 20 minut es af t er c ont rast injec t ion w it h 0.2 mmol/Kg of gadolinium- based MR c ont rast agent (127). CT imaging, alt hough used less f requent ly , has been used t o assess RV dy splasia (127,131). How ev er, giv en t hat pat ient s w it h RV dy splasia f requent ly rec eiv e c ardiodef ibrillat ors, CT imaging may represent an import ant alt ernat iv e t o MRI. CT has exc ellent depic t ion of int ramy oc ardial f at (F ig. 939) (68), and 3D MDCT met hods now permit c ine imaging t o look f or w all mot ion abnormalit ies.

F igure 9- 38 A: T his panel show s an axial delay ed enhanc ed image f rom an arrhy t hmogenic right v ent ric ular dy splasia pat ient . T he signal int ensit y of t he right v ent ric ular (RV) my oc ardium is inc reased, similar t o t hat of epic ardial f at . B: T his panel show s t he same lev el of t he my oc ardium as panel A, using t he same pulse sequenc e w it h c hemic al shif t f at suppression. T he enhanc ed RV ant erior w all is w ell apprec iat ed (ar r ow s), and f at in t he ant erior c hest w all has low signal int ensit y (ar r ow head). C : T his panel show s t he same pulse sequenc e as panel B, exc ept t hat body c oil w as used f or signal t ransmission and rec ept ion. Alt hough t he signal- t o- noise rat io is dec reased c ompared w it h surf ac e c oil imaging in panels A and B, t he signal int ensit y is more unif orm ac ross t he f ield of v iew . T his c onf irms t hat t he RV signal is inc reased (ar r ow s) bec ause of inc reased my oc ardial signal rat her t han proximit y t o t he phased array surf ac e c oil. Wit h permission f rom T andri H, Saranat han M, Rodriguez ER, et al. Noninv asiv e det ec t ion of my oc ardial f ibrosis in arrhy t hmogenic right v ent ric ular c ardiomy opat hy using delay ed- enhanc ement magnet ic resonanc e imaging. J Am Coll Car diol. 2005;45: 98–103.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1512

9 - Heart and Pericardium

F igure 9- 39 A: Cont rast - enhanc ed, mult idet ec t or c omput ed t omographic image in t he axial plane show ing an enlarged out f low t rac t (ar r ow heads) in a pat ient w it h right v ent ric ular dy splasia (B). Cont rast - enhanc ed, mult idet ec t or c omput ed t omographic image in t he axial plane show ing f oc al f at inf ilt rat ion of t he lef t v ent ric le w it h w all t hinning (ar r ow s) in a pat ient w it h right v ent ric ular dy splasia. Wit h permission f rom T andri H, Saranat han M, Rodriguez ER, et al. Noninv asiv e det ec t ion of my oc ardial f ibrosis in arrhy t hmogenic right v ent ric ular c ardiomy opat hy using delay ed- enhanc ement magnet ic resonanc e imaging. J Am Coll Car diol. 2005;45: 98–103.

P.696

Pericardial Disease T he peric ardium c onsist s of t w o lay ers: a f ibrous out er lay er and an inner serous one. T he serous lay er is inseparable f rom t he f ibrous lay er, as t he f ibrous lay er passes around t he heart . About 2 t o 3 c m abov e t he root of t he aort a and pulmonary v essels, t he serous lay er separat es f rom t he f ibrous lay er and f olds bac k on it self t o env elop part s of t he aort a and pulmonary v essels and t he heart . T he port ion of t he serous lay er t hat is c losely at t ac hed t o t he f ibrous lay er is t he pariet al peric ardium (F ig. 9- 40). T he ref lec t ed serous lay er t hat runs ov er t he surf ac e of t he heart is t he v isc eral peric ardium or epic ardium. T he normal peric ardium (c ombinat ion of v isc eral and pariet al lay ers w it hout any int erv ening f luid) c an be seen on CT or MRI as a t hin linear st ruc t ure t hat measures less t han 2 mm. Bec ause of a pauc it y of f at in t his region, it f requent ly c annot be seen ov er t he lef t v ent ric le.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1513

9 - Heart and Pericardium Peric ardial disease c an c onsist of c onst ric t iv e peric ardit is, peric ardial ef f usions, and c ongenit al anomalies, suc h as c ongenit al absenc e of t he peric ardium and peric ardial c y st s.

Constrictive Pericarditis Bec ause bot h rest ric t iv e c ardiomy opat hy and c onst ric t iv e peric ardit is hav e similar c linic al signs and sy mpt oms, MRI and CT imaging c an be usef ul in dif f erent iat ing bet w een t he t w o ent it ies. MRI is v ery usef ul in making t his dist inc t ion, as t he peric ardium has normal t hic kness in rest ric t iv e c ardiomy opat hy (8,92,123). CT and MRI c an help t o dif f erent iat e bet w een t hese t w o c ondit ions and may be espec ially usef ul, bec ause c onst ric t iv e peric ardit is c an be t reat ed surgic ally by st ripping t he peric ardium, Const ric t iv e peric ardit is result s f rom progressiv e peric ardial f ibrosis and c alc if ic at ion, leading t o rest ric t ion of c ardiac v ent ric les during diast ole. Const ric t ion may f ollow any peric ardial injury t hat c auses an inf lammat ory response, suc h as inf ec t ious peric ardit is, c onnec t iv e t issue disease, neoplasm, renal f ailure, c ardiac surgery , and radiat ion t herapy . As ment ioned abov e, t he P.697 normal peric ardium is v ery t hin (1 t o 2 mm). A t hic kness of 4 mm or more indic at es peric ardial t hic kening and in a proper c linic al set t ing is t he f inding t hat is diagnost ic of c onst ric t iv e peric ardit is (F ig. 9- 41). Ot her assoc iat ed f indings are markedly dilat ed inf erior v ena c av a, hepat ic v eins, and right at rium.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1514

9 - Heart and Pericardium F igure 9- 40 Coronal MRI w it h ov erlay illust rat es t he pot ent ial spac e

(peric ardial c av it y ) c reat ed by t he serous lay er t hat ref lec t s on it self about 2 t o 3 c m abov e t he root of t he aort a and pulmonary art ery . T he sit e of ref lec t ion is know n as a rec ess.

F igure 9- 41 Const ric t iv e peric ardit is. Axial dark blood HAST E image show s a t hic kened peric ardium (>4 mm) (ar r ow s), normal my oc ardial t hic kness, large right and lef t at ria, and relat iv ely small v ent ric ular size. MR may also show a dilat ed IVC or paradoxic al sept al mot ion bec ause of inc reased right - sided pressure. Wit h permission f rom Poust c hi- Amin M, Gut ierrez F R, Brow n JJ, et al. How t o plan and perf orm a c ardiac MR imaging examinat ion. Radiol Clin Nor t h Am . 2004;42:497–514.

It is import ant t o not e t hat c alc if ic at ion of t he peric ardium in c onst ric t iv e peric ardit is is dark on MR images. If needed, nonc ont rast CT c an help in v isualizing peric ardial c alc if ic at ion in pat ient s w it hout demonst rable peric ardial t hic kening on MRI but w it h a high c linic al suspic ion of c onst ric t iv e peric ardit is (F ig. 9- 42).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1515

9 - Heart and Pericardium

F igure 9- 42 Nonc ont rast CT image demonst rat es small areas of c alc if ic at ion (ar r ow s) in t he peric ardium in a pat ient w it h c onst ric t iv e peric ardit is. T hese c alc if ic at ions w ill appear dark on MR and are dif f ic ult t o ident if y .

Pericardial Effusions Peric ardial ef f usions c an be c aused by any number of ent it ies, inc luding v iral peric ardit is, uremia, c onnec t iv e t issue disorders, radiat ion t o t he mediast inum, and met ast at ic disease. T hey c an present af t er c ardiac surgery as a post peric ardiot omy sy ndrome, or af t er MI (Dressler sy ndrome). T he most c ommon et iology of a t ransudat iv e ef f usion is c ongest iv e heart f ailure (8). T hese t ransudat iv e or serous ef f usions w ill appear as a low at t enuat ion c irc umf erent ial f luid c ollec t ion surrounding t he heart on CT , and t hey w ill appear dark on T 1- w eight ed and bright on T 2- w eighed MRI. More prot einac eous or exudat iv e f luids w ill hav e a higher at t enuat ion appearanc e on CT (20 t o 60 HU) and w ill hav e short er T 1 and T 2 relaxat ion t imes on MRI. Ac ut e hemorrhage on CT w ill appear bright (60 t o 80 HU) but w ill dev elop a lay ered hemat oc rit ef f ec t subac ut ely . T he appearanc e of peric ardial blood on MRI w ill be v ariable, depending on t he st age, w it h older bloody or serosanguinous c ollec t ions demonst rat ing T 1 short ening sec ondary t o met hemoglobin f ormat ion (8). It is import ant t o rec ognize t he CT and MRI signs of t amponade and t o inf orm t he ref erring c linic ian, as t amponade c an lead t o rapid hemody namic c ompromise (F ig. 9- 43). F irst desc ribed on

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1516

9 - Heart and Pericardium ec hoc ardiography , t hese f indings are f lat t ening of t he right v ent ric le and at rium and dilat at ion of t he inf erior v ena c av a. On c ine images, t here is c ollapse of t he right v ent ric ular f ree w all during early diast ole (93).

Congenital Absence of the Pericardium Congenit al absenc e of t he peric ardium may be c omplet e or part ial. Part ial absenc e is more c ommon and is usually P.698 on t he lef t . Pat ient s t end t o be asy mpt omat ic . T he f indings on CT and MRI c ent er on t he lac k of v isualizat ion of t he peric ardium and sec ondary signs, inc luding post erior and lef t w ard shif t of t he c ardiac axis, prominent at rial appendage, and separat ion of aort a and main pulmonary art ery (F ig. 9- 44). Lac k of v isualizat ion of t he peric ardium is not suf f ic ient f or t he diagnosis, as a normal int ac t peric ardium may not be seen ov er t he lef t at rial appendage and lef t v ent ric le. T he signif ic anc e of part ial absenc e of t he peric ardium lies in t he inc reased (but rare) risk of herniat ion and st rangulat ion of t he lef t at rial appendage.

F igure 9- 43 Cont rast - enhanc ed CT image demonst rat es a large peric ardial ef f usion (E), w it h f lat t ening of t he right v ent ric ular (RV) f ree w all and right

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1517

9 - Heart and Pericardium at rium (RA) (ar r ow s). T hese f indings are indic at iv e of t amponade. LV, lef t v ent ric le; LA, lef t at rium.

F igure 9- 44 CT w it hout int rav enous c ont rast in a pat ient w it h a spont aneous lef t pneumot horax (A t o C ). No lef t peric ardium w as seen, and t he c ardiac apex w as not ed t o be rot at ed post eriorly and lef t w ard. A pneumoperic ardium w as also not ed w it h gas in t he superior aort ic rec ess (ant erior, right lat eral, and post erior port ions) (st r aight ar r ow ) w it h inc reased dist anc e bet w een t he aort a and t he main pulmonary art ery (c ur v ed ar r ow ). F indings w ere diagnost ic of c ongenit al absenc e of t he peric ardium.

Pericardial Cysts Cy st s and div ert ic ula are w ell- marginat ed, f luid- c ont aining st ruc t ures t hat abut t he heart . When t he c ollec t ion is separat ed f rom t he peric ardial c av it y , it is a peric ardial c y st . When t he c onnec t ion w it h t he peric ardial c av it y is maint ained, it is know n as a peric ardial div ert ic ulum. Bot h st ruc t ures are most c ommonly seen in t he right ant erior c ardiophrenic angle, but t hey may be present along any of t he peric ardial surf ac es. T he dif f erent ial f or a peric ardial c y st in an unusual loc at ion w ould inc lude a bronc hogenic or t hy mic c y st (133). On CT , peric ardial c y st s are low in at t enuat ion (F ig. 9- 45). On MRI, peric ardial c y st s are t y pic ally low or int ermediat e signal int ensit y on T 1- w eight ed images

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1518

9 - Heart and Pericardium

and homogeneous high int ensit y on T 2- w eight ed images. T hey do not enhanc e w it h t he administ rat ion of eit her iodinat ed c ont rast agent s or gadolinium (133). Oc c asionally , a c y st may c ont ain prot einac eous f luid and, t hus, may hav e a high signal int ensit y on T 1- w eight ed MRI (133).

Tumors Primary c ardiac t umors are rare and approximat ely 80% are benign. Sec ondary t umors inv olv ing t he heart are 40 t o 50 P.699 t imes more f requent t han primary t umors (23,54). In general most met ast asis and malignant t umors are broad based or inv ade t he my oc ardium. Most benign t umors are int raluminal and are at t ac hed by a narrow st alk. Most t umors enhanc e w it h gadolinium or iodinat ed c ont rast agent . T he exc ept ion t o t his are f ibromas, w hic h oc c ur w it hin t he my oc ardium and do not enhanc e c ent rally but hav e an enhanc ing c apsule, and lipomas, w hic h do not enhanc e and hav e a c harac t erist ic appearanc e of f at at t enuat ion on CT and f at signal on MRI (57). Primary t umors of t he heart inc lude my xoma (t he most f requent benign c ardiac t umor, usually w it hin t he lef t at rium, at t ac hed by a t hin st alk at t he f ossa ov alis) (F ig. 9- 46), lipoma (usually right at rium), angiosarc oma (most c ommon malignant , arising f rom t he right at rium), rhabdomy oma (f requent t umor in c hildren), f ibroma (low c ent ral signal on T 2, P.700 w it h a bright c apsule), and hemangioma (“ light bulb” appearanc e on T 2w eight ed images). F ibroelast omas (F ig. 9- 47) are t he most c ommon t umors of c ardiac v alv es, oc c urring most c ommonly on t he aort ic v alv e and next on t he mit ral v alv e (usually at rial side) (125). Most rec ent ly , t hese hav e been desc ribed as demonst rat ing delay ed gadolinium- based c ont rast enhanc ement on T 1- w eight ed MRI (15), likely bec ause of t heir f ibrous c omponent .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1519

9 - Heart and Pericardium

F igure 9- 45 F luid at t enuat ion st ruc t ure (ast er isk) in t he right ant erior c ardiophrenic angle represent s a peric ardial c y st .

F igure 9- 46 Right at rial my xoma. Axial dark blood HAST E (A) show s a bilobed mass (ar r ow ) st raddling t he t ric uspid v alv e. Not e t he relat iv ely bright signal of t he mass on t his T 2- w eight ed sequenc e. Images are ac quired in diast ole and t hus do not demonst rat e t he loc at ion of t he mass t hroughout t he c y c le. Axial bright blood c ine GRE image obt ained in diast ole (B) and sy st ole (C ) show t hat t he mass arises f rom t he right at rium in t he region of t he f ossa ov alis w it h t he point of t umor at t ac hment at t he int ra- at rial sept um. Wit h permission Poust c hi- Amin M, Gut ierrez F R, Brow n JJ, et al. How t o plan and perf orm a c ardiac MR imaging examinat ion. Radiol Clin Nor t h Am . 2004;42:497–514.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1520

9 - Heart and Pericardium

F igure 9- 47 F ibroelast oma (A, B). Long axis T rueF ISP images demonst rat e a small nodular mass (ar r ow ) along t he at rial surf ac e of t he lat eral mit ral v alv e leaf let . Dif f erent ial might inc lude a small t hrombus or v eget at ion.

F igure 9- 48 CT (A) af t er int rav enous c ont rast show s nodular t hic kening of t he peric ardium w it h enhanc ement (ar r ow ) (B). Spic ulat ed lef t upper- lobe mass (M) and t hic kened int erlobular sept a (suggest ing ly mphangit ic spread) w ere also not ed. Biopsy c onf irmed peric ardial met ast ases f rom a bronc hogenic c anc er.

Sec ondary t umors of t he heart inc lude hemat ogenous met ast at ic disease t o my oc ardium and peric ardium but most f requent ly met ast at ic disease as an ext ension f rom t umors of t he adjac ent lung or mediast inal st ruc t ures. In direc t inv asion, t he underly ing malignanc y is most of t en lung c arc inoma, bot h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1521

9 - Heart and Pericardium bec ause of t he proximit y t o t he heart and bec ause of t he prev alenc e of t his t umor (23). Aut opsy has show n t hat bronc hogenic c arc inoma is t he primary t umor in 36% of pat ient s w it h c ardiac met ast ases (F ig. 9- 48); nonsolid primary malignanc ies (e.g., leukemia, ly mphoma (F ig. 9- 49), and Kaposi sarc oma) in 20%, c arc inoma of t he breast in 7%, and c arc inoma of t he

esophagus in 6% (23,69). Less f requent ly seen are hemat ogenous met ast ases f rom melanoma (F ig. 9- 50), ly mphoma, or breast ; of all t umors, met ast ases t o t he heart are seen t he most f requent ly in melanoma pat ient s, oc c urring in 64% t o 71% (69). Ext ension of t umors of t he upper abdomen c an also oc c ur t hrough t he IVC int o t he right at rium (23). T he most c ommon mass of t he heart in general is a t hrombus, w hic h most f requent ly inv olv es t he lef t at rium or v ent ric le. It is import ant t o not e t hat some normal c ardiac anat omic st ruc t ures may be c onf used w it h t hrombus or mass bot h on MRI and ec hoc ardiography , and it is import ant t o rec ognize t hese normal st ruc t ures as suc h (110). T he c rist a t erminalis and assoc iat ed Chiari net w ork, a nodular f ilament ous st ruc t ure t hat runs along t he post erior aspec t of t he right at rium, may be mist aken as t hrombus. P.701 Lipomat ous hy pert rophy of t he int erat rial sept um is ec hogenic on ec hoc ardiography and it may be mist aken as a mass, but it c learly c an be ident if ied as f at by it s low at t enuat ion on CT imaging and it s signal c harac t erist ic s (bright on T 1 and T 2, signal suppressed w it h spec t ral f at sat urat ion) on MRI (F ig. 9- 51).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1522

9 - Heart and Pericardium

F igure 9- 49 Post - int rav enous c ont rast CT show s a large ant erior mediast inal mass w it h inv asion of t he superior peric ardial rec ess (y ellow ar r ow ). Biopsy rev ealed an aggressiv e B- c ell ly mphoma.

F igure 9- 50 Hemat ogenous spread in a pat ient w it h met ast at ic melanoma (A). Axial T 1- w eight ed spin- ec ho MR image show s melanoma met ast at ic t o t he heart . T he bright ness of lesions w it hin t he lef t v ent ric ular my oc ardium (ar r ow s) is at t ribut able t o melanin (B). Axial T 2- w eight ed spin- ec ho MR image show s lesions w it hin t he lef t v ent ric ular my oc ardium, w hic h remain bright . (Court esy of Vinc ent Mc Dermot t , MD, Bon Sec ours Hospit al, Cork, Ireland.) Wit h permission f rom Chiles C, Woodard PK, Gut ierrez F R, et al. Met ast at ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1523

9 - Heart and Pericardium inv olv ement of t he heart and peric ardium: CT and MR imaging. Radiogr aphic s. 2001;21:439–449.

F igure 9- 51 Coronal (A) and horizont al long axis (B) blac k- blood images of t he heart show an int erat rial lipoma (L). Not e t hat t his f ollow s t he signal of subc ut aneous and epic ardial f at . T he st ruc t ure is round and enc apsulat ed. In c omparison, not e t he appearanc e of lipomat ous hy pert rophy of t he int erat rial sept um show n on images B and C . T ransv erse blac k- blood image (B) show s dif f use int erat rial f at . On a T rueF ISP image obt ained more inf eriorly , t he f at show s a dumbbell appearanc e (shor t ar r ow ) and inf ilt rat es t he c rist a t erminalis (long ar r ow ). Lipomat ous hy pert rophy of t he int erat rial sept um c an be mist aken as a mass on ec hoc ardiography .

Valvular Disease Quant if ic at ion of blood f low t hrough heart v alv es is of c linic al int erest in t he assessment of t he sev erit y of v alv ular heart disease. Alt hough v alv ular st enosis may be adequat ely ev aluat ed by measuring t ransv alv ular pressure

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1524

9 - Heart and Pericardium gradient s using Doppler c ardiac ec ho or c ardiac c at het erizat ion, t radit ional met hods f ail t o prov ide c onsist ent ly reliable and ac c urat e quant if ic at ion of v alv ular regurgit at ion (110,132). Cine MRI has been f ound t o be an ef f ec t iv e P.702 t ec hnique f or ev aluat ing v ent ric ular and v alv ular f unc t ion in c ert ain v alv ular heart diseases (22,29,32,45,48,120).

F igure 9- 52 Coronal T rueF ISP images t hrough t he aort ic v alv e in (A) sy st ole and (B) diast ole. A jet of aort ic st enosis (ar r ow ) is ident if ied in sy st ole. T he doming of t he aort ic v alv e in diast ole suggest s t hat t his v alv e is bic uspid.

Cardiac MRI t ec hniques c an demonst rat e t he presenc e and quant if y t he sev erit y of v alv ular heart disease. MR examinat ion of v alv ular dy sf unc t ion inc ludes direc t demonst rat ion of t he jet of v alv ular st enosis or regurgit at ion as w ell as demonst rat ion of c hamber dilat ion or hy pert rophy . Cine MRI display s signal v oid in areas of t urbulent f low relat ed t o eit her v alv ular disease, suc h as st enosis or insuf f ic ienc y . Size of signal loss is dependent on degree of t urbulent f low and on c hosen ec ho t ime (T E). Veloc it y enc oded c ine (VENC) MRI c an be used f or measurement of peak v eloc it ies t hrough area of st enosis. Care must be t aken t o use a sequenc e w it h a VENC abov e t he est imat ed peak v eloc it y t o av oid inac c urac ies c aused by aliasing. Using a modif ied Bernoulli equat ion (ОґP = 4V 2), t he pressure gradient (P) ac ross t he v alv e or st enot ic segment of v essel c an be est imat ed, w hen sy st olic peak v eloc it y (V) is P.703 know n. An art erial peak pressure gradient of more t han 25 mm Hg is c onsidered hemody namic ally signif ic ant . T he regurgit ant f rac t ion in aort ic v alv e insuf f ic ienc y c an be det ermined by c alc ulat ing t he dif f erenc e of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1525

9 - Heart and Pericardium right and lef t v ent ric ular st roke v olumes. T his is only ac c urat e if no shunt or

ot her v alv e disease is present (29). A more ac c urat e met hod may be t o assess t he rat io of regurgit ant t o f orw ard f low ac ross a v alv e. Most MR v endors hav e sof t w are t hat f ac ilit at es t he c alc ulat ion of t hese v alues f rom c ine phasec ont rast images.

F igure 9- 53 A: Pat ient w it h an anomalous right c oronary art ery (RCA) arising f rom t he lef t c oronary c usp. T his art ery runs epic ardially bet w een t he asc ending aort a (AAo) and pulmonary out f low t rac t , plac ing t he pat ient at risk f or isc hemia and sudden deat h (B). Pat ient w it h an anomalous lef t c oronary art ery sy st em arising f rom t he right c oronary art ery c usp. T he ent ire sy st em runs ant erior t o t he pulmonary out f low t rac t . As no v essel runs bet w een t he aort a and pulmonary out f low t rac t , t his is c onsidered a benign v ariant . LAD, lef t ant erior desc ending; LCX, lef t c irc umf lex; L Main, lef t main c oronary art eries.

Bot h MRI and CT imaging c an be used t o assess t he number and appearanc e of v alv e leaf let s, suc h as in t he diagnosis of bic uspid aort ic v alv e. MR images are ac quired and CT c ine images c an be c onst ruc t ed in t he plane of t he aort ic v alv e. Alt ernat iv ely , one may look f or “ doming” of t he bic uspid aort ic v alv e during sy st ole on c oronal or aort ic out f low v iew s of t he heart (F ig. 952).

Anomalous Coronary Arteries Bot h c oronary MRA and CT angiography c an be used t o assess anomalous c oronary art eries. Some c ongenit al anomalous c oronary art ery arrangement s are assoc iat ed w it h sudden deat h (36). Anomalous c oronary art eries assoc iat ed w it h sudden deat h inc lude an RCA or LAD t rav eling bet w een t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1526

9 - Heart and Pericardium aort a and pulmonic out f low t rac t (110). Some of t hese anomalies are also

dif f ic ult t o ev aluat e w it h c onv ent ional x- ray c oronary angiography . Bec ause of t heir 3D c apabilit ies, MRI and CT c an be usef ul as problem- solv ing t ools t o ev aluat e t he exac t pat hw ay of an anomalous c oronary art ery in w ay s c onv ent ional x- ray angiography c annot (F ig. 9- 53).

REFERENCES 1. Ac henbac h S, Daniel WG. Imaging of c oronary at herosc lerosis using c omput ed t omography : c urrent st at us and f ut ure direc t ions. Cur r At her osc ler Rep. 2004;6:213–218. 2. Ac henbac h S, Giesler T , Ropers D, et al. Comparison of image qualit y in c ont rast - enhanc ed c oronary - art ery v isualizat ion by elec t ron beam t omography and ret rospec t iv ely elec t roc ardiogram- gat ed mult islic e spiral c omput ed t omography . Inv est Radiol. 2003;28:119–128. 3. Ac henbac h S, Giesler T , Ropers D, et al. Det ec t ion of c oronary art ery st enoses by c ont rast - enhanc ed, ret rospec t iv ely elec t roc ardiographic ally gat ed, mult islic e spiral c omput ed t omography . Cir c ulat ion. 2001;103:2535–2538. 4. Ac henbac h S, Hof f mann U, F erenc ik M, et al. T omographic c oronary angiography by EBCT and MDCT . Pr og Car diov asc Dis. 2003;46:185–195. 5. Agat st on AS, Janow it z WR, Hildner F J, et al. Quant if ic at ion of c oronary art ery c alc ium using ult raf ast c omput ed t omography . J Am Coll Car diol. 1990;15:827–832. 6. Americ an Heart Assoc iat ion. Hear t Disease and St r oke St at ist ic s 2005 Updat e. Dallas: Americ an Heart Assoc iat ion, 2004: p3–43. 7. Applic at ion Guide: SOMAT OM Sensat ion Car diac 64. F orc hheim: Siemens AG Medic al Solut ions, 2004. 8. Axel L. Assessment of peric ardial disease by magnet ic resonanc e and c omput ed t omography . J Magn Reson Im aging. 2004;19: 819–826. 9. Baer F M, Vot h E, Sc hneider CA, et al. Comparison of low - dose dobut aminegradient —ec ho magnet ic resonanc e imaging w it h f luorodeoxy gluc ose in pat ient w it h c hronic c oronary art ery disease. Cir c ulat ion. 1995;91:1006–1015. 10. Basso C, T hiene G, Corrado D, et al. Arrhy t hmogenic right v ent ric ular c ardiomy opat hy : dy splasia, dy st rophy , or my oc ardit is? Cir c ulat ion. 1996;94:983–991.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1527

9 - Heart and Pericardium 11. Bec ker CR, Knez A, Leber A, et al. Det ec t ion of c oronary art ery st enoses w it h mult islic e helic al CT angiography . J Com put Assist T om ogr . 2002;26:750–755. 12. Bec ker CR, Knez A. Past , present and f ut ure perspec t iv e of c ardiac c omput ed t omography . J Magn Reson Im aging. 2004;19: 676–685. 13. Bley T A, Ghanem NA, F oell D, et al. Comput ed t omography w it h 370millisec ond gant ry rot at ion t ime: ev aluat ion of t he best image rec onst ruc t ion int erv al. J Com put Assist T om ogr . 2005;29:1–5. 14. Bogaert J, Kuzo R, Dy markow ski S, et al. Coronary Art ery Imaging w it h Real- t ime Nav igat or T hree- dimensional T urbo- F ield- Ec ho MR Coronary Angiography : Init ial Experienc e. Radiology . 2003;226(3):707–716. 15. Boot sv eld A, Puet z J, Grube E. Inc ident al f inding of a papillary f ibroelast oma on t he aort ic v alv e in 16 slic e mult i- det ec t or row c omput ed t omography . Hear t . 2004;90:e35.

16. Bot nar RM, St uber M, Danias PG, et al. Improv ed c oronary art ery def init ion w it h T 2- w eight ed, f ree- breat hing, t hree- dimensional c oronary MRA. Cir c ulat ion. 1999;99:3139–3148. 17. Boxerman JL, Mosher T J, Mc Veigh ER, et al. Adv anc ed MR imaging t ec hniques f or ev aluat ion of t he heart and great v essels. Radiogr aphic s. 1998;18:543–564. 18. Boxt LM. How t o perf orm c ardiac MR imaging. In: Boxt LM, ed.: Car diac MR im aging. Magnet ic r esonanc e im aging c linic s of Nor t h Am er ic a. Philadelphia: WB Saunders, 1996: 191–216. 19. Bunc e NH, Jhoot i P, Keegan J, et al. Ev aluat ion of f ree- breat hing t hreedimensional magnet ic resonanc e c oronary angiography w it h hy brid ordered phase enc oding (HOPE) f or t he det ec t ion of proximal c oronary art ery st enosis. J Magn Reson Im aging. 2001;14(6):677–684. 20. Buser PT , Auf f ermann W, Holt WW, et al. Noninv asiv e ev aluat ion of global lef t v ent ric ular f unc t ion w it h c ine NMR. J Am Coll Car diol. 1989;13:1294–1300. 21. Cademart iri F , Mollet N, v an der Lugt A, et al. Non- inv asiv e 16- row mult islic e CT c oronary angiography : usef ulness of saline c haser. Eur Radiol. 2003;14:178–183. 22. Carroll JD. Cardiac c at het erizat ion and ot her imaging modalit ies in t he ev aluat ion of v alv ular heart disease. Cur r Opin Car diol. 1993;8:211–215. 23. Chiles C, Woodard PK, Gut ierrez F R, et al. Met ast at ic inv olv ement of t he heart and peric ardium: CT and MR imaging. Radiogr aphic s. 2001;21:439–449.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1528

9 - Heart and Pericardium 24. Choi CJ, Haji- Momenian S, Dimaria JM, et al. Inf arc t inv olut ion and improv ed f unc t ion during healing of ac ut e my oc ardial inf arc t ion: t he role of mic rov asc ular obst ruc t ion. J Car diov asc Magn Reson. 2004;6:917–925. 25. Choi KM, Kim RJ, Gubernikof f G, et al. T ransmural ext ent of ac ut e my oc ardial inf arc t ion predic t s long- t erm improv ement in c ont rac t ile f unc t ion. Cir c ulat ion. 2001;104:1101–1107. 26. Corrado D, Basso C, T hiene G, et al. Spec t rum of c linic opat hologic manif est at ions of arrhy t hmogenic right v ent ric ular c ardiomy opat hy /dy splasia: a mult ic ent er st udy . J Am Coll Car diol. 1997;30:1512–1520. 27. Danias PG, St uber M, Bot nar RM, et al. Coronary MR angiography c linic al applic at ions and pot ent ial f or imaging c oronary art ery disease. Mag Reson Im aging Clin N Am . 2003;11:81–99. 28. De Sut t er J, De Bac quer D, Kot sev a K, et al. Sc reening of f amily members of pat ient s w it h premat ure c oronary heart disease: Result s f rom t he EUROASPIRE II f amily surv ey . Eur Hear t J. 2003;24:249–257. 29. Didier D, Rat ib O, Lerc h R, et al. Det ec t ion and quant if ic at ion of v alv ular heart disease w it h dy namic c ardiac MR imaging. Radiogr aphic s. 2000;20:1279–1299. 30. Dinsmore RE, Wismer GL, Lev ine RA, et al. MRI of t he heart : posit ioning and gradient angle selec t ion f or opt imal imaging plane. AJR Am J Roent genol. 1984;143:1135–1142. 31. Duerinc kx AJ, Urman MK. T w o- dimensional c oronary MR angiography : analy sis of init ial c linic al result s. Radiology . 1994;193: 731–738. P.704 32. Dulc e MC, Most bec k G, O'Sulliv an MM, et al. Sev erit y of aort ic regurgit at ion: int erst udy reproduc ibilit y of measurement s w it h v eloc it y enc oded c ine MR imaging. Radiology . 1992;185:235–240. 33. Dulc e MC, Most bec k GH, F riese KK, et al. Quant if ic at ion of t he lef t v ent ric ular v olumes and f unc t ion w it h c ine MR imaging: c omparison of geomet ric models w it h t hree- dimensional dat a. Radiology . 1993;188:371–376.

34. Edelman RR, Manning WJ, Burst ein D, et al. Coronary art eries: breat h- hold MR angiography . Radiology . 1991;181(3):641–643. 35. F alk R. At rial f ibrillat ion. N Engl J Med. 2001;344:1067–1077. 36. F elmeden D, Singh SP, Lip GY . Anomalous c oronary art eries of aort ic origin. Int J Clin Pr ac t . 2000;54(6):390–394.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1529

9 - Heart and Pericardium 37. F inn JP, Baskaran V, Carr J, et al. T horax: low dose c ont rast - enhanc ed

t hree- dimensional MR angiography w it h subsec ond t emporal resolut ion—init ial result s. Radiology . 2002;224: 896–904. 38. F inn JP, Edelman RR. Blac k- blood and segment ed k- spac e magnet ic resonanc e angiography . Magn Reson Im aging Clin N Am . 1993;1(2):349–357. 39. F isc her SE, Mc Kinnon GC, Maier SE, et al. Improv ed my oc ardial t agging c ont rast . Magn Reson Med. 1993;30:191–200. 40. F lohr T , Ohnesorge B. Heart rat e adapt iv e opt imizat ion of spat ial and t emporal resolut ion f or elec t roc ardiogram- gat ed mult islic e spiral CT of t he heart . J Com put Assist T om ogr . 2001;25:907–923. 41. F lohr T , St ierst orf er K, Raupac h R, et al. Perf ormanc e ev aluat ion of a 64slic e CT sy st em w it h z- f ly ing f oc al spot . Rof o. 2004;176: 1803–1810. 42. F lohr T , St ierst orf er K, Raupac h R, et al. Perf ormanc e ev aluat ion of a 64slic e CT sy st em w it h z- f ly ing f oc al spot . Rof o. 2004;176: 1803–1810. 43. F lohr T , St ierst orf er K, Raupac h R, et al. Perf ormanc e ev aluat ion of a 64slic e CT sy st em w it h z- f ly ing f oc al spot . Rof o. 2004;176: 1803–1810. 44. F ont aine G, F ont aliran F , F rank R. Arrhy t hmogenic right v ent ric ular c ardiomy opat hies: c linic al f orms and main dif f erent ial diagnosis. Cir c ulat ion. 1998;97:1532–1535. 45. F ujit a N, Chazouilleres AF , Hart iala JJ, et al. Quant if ic at ion of mit ral regurgit at ion by v eloc it y - enc oded c ine magnet ic resonanc e imaging. J Am Coll Car diol. 1994;23:951–958. 46. Gerber T C, Kuzo RS, Lane GE, et al. Image qualit y in a st andardized algorit hm f or minimally inv asiv e c oronary angiography w it h mult islic e spiral c omput ed t omography . J Com put Assist T om ogr . 2003;27:62–69. 47. Ghay e B, Szapiro D, Dac her JN, et al. Perc ut aneous ablat ion f or at rial f ibrillat ion: t he role of c ross- sec t ional imaging. Radiogr aphic s. 2003;23:S19–S33. 48. Globit s S, Higgins CB. Assessment of v alv ular heart disease by magnet ic resonanc e imaging. Am Hear t J. 1995;129: 369–381. 49. Greess H, Wolf H, Baum U, et al. Dose reduc t ion in c omput ed t omography by at t enuat ion- based on- line modulat ion of t ube c urrent : ev aluat on of six anat omic al regions. Eur Radiol. 2000;10: 391–394. 50. Haissaguerre M. Suc c essf ul c at het er ablat ion of at rial f ibrillat ion. J Car diov asc Elec t r ophy siol. 1994;5:1045–1052.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1530

9 - Heart and Pericardium 51. Halliburt on SS, St illman AE, Lieber M, et al. Pot ent ial c linic al impac t of

v ariabilit y in t he measurement of c oronary art ery c alc if ic at ion w it h sequent ial MDCT . AJR Am J Roent genol. 2005;184: 643–648. 52. Hazirolan T , Gupt a SN, Mohamed MA, et al. Reproduc ibilit y of blac k- blood c oronary v essel w all MR imaging. J Car diov asc Magn Reson. 2005;7:409–413. 53. Herzog C, Abolmaali N, Balzer JO, et al. Heart - rat e- adapt ed image rec onst ruc t ion in mult idet ec t or- row c ardiac CT : inf luenc e of phy siologic al and t ec hnic al prerequisit e on image qualit y . Eur Radiol. 2002;12:2670–2678. 54. Higgins CB. Ac quired heart disease. In: Higgins CB, Hric ak H, Helms CA, eds. Magnet ic r esonanc e im aging of t he body , 3rd ed. Philadelphia: Lippinc ot t - Rav en Publishers, 1997: 409–460. 55. Hillenbrand HB, Lima JA, Bluemke DA, et al. Assessment of my oc ardial sy st olic f unc t ion by t agged magnet ic resonanc e imaging. J Car diov asc Magn Reson. 2000;2:57–66. 56. Hof f F L, T urner DA, Wang JZ, et al. Semiaut omat ic ev aluat ion of lef t v ent ric ular diast olic f unc t ion w it h c ine magnet ic resonanc e imaging. Ac ad Radiol. 1994;1:237–242. 57. Hof f mann U, Globit s S, Sc hima W, et al. Usef ulness of magnet ic resonanc e imaging of c ardiac and parac ardiac masses. Am J Car diol. 2003;92(7):890–895. 58. Hof f mann U, Moselew ski F , Cury RC, et al. Predic t iv e v alue of 16- slic e mult idet ec t or spiral c omput ed t omography t o det ec t signif ic ant obst ruc t iv e c oronary art ery disease in pat ient s at high risk f or c oronary art ery disease: pat ient - v ersus segment - based analy sis. Cir c ulat ion. 2004;110:2638–2643. 59. Hong C, Bae KT , Pilgram T K. Coronary art ery c alc ium: Ac c urac y and reproduc ibilit y of measurement s w it h mult i- det ec t or row CT —Assessment of ef f ec t s of dif f erent t hresholds and quant if ic at ion met hods. Radiology . 2003;227:795–801. 60. Hong C, Chry sant GS, Woodard PK, et al. Coronary art ery st ent pat enc y assessed w it h in- st ent c ont rast enhanc ement measurement in mult i- det ec t or row CT angiography . Radiology . 2004;233:286–291. 61. Horiguc hi J, Y amamot o H, Akiy ama Y , et al. Variabilit y of repeat ed c oronary art ery c alc ium measurement s by 16- MDCT w it h ret rospec t iv e rec onst ruc t ion. AJR Am J Roent genol. 2005;184: 1917–1923. 62. Hundt W, Rust F , St abler A, et al. Dose reduc t ion in mult islic e c omput ed t omography . J Com put Assist T om ogr . 2005;29: 140–147.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1531

9 - Heart and Pericardium 63. Hut t er A, Kedan I, Srokow ski T P, et al. Coronary magnet ic reasonanc e angiography . Sem in Roent genol. 2003;38:330–341. 64. Kellman P, Arai AE, Mc Veigh ER, et al. Phase- sensit iv e inv ersion rec ov ery f or det ec t ing my oc ardial inf arc t ion using gadolinium- delay ed hy perenhanc ement . Magn Reson Med. 2002;47: 372–383. 65. Kim RJ, Chen EL, Lima JA, et al. My oc ardial Gd- DT PA kinet ic s det ermine MRI c ont rast enhanc ement and ref lec t t he ext ent and sev erit y of my oc ardial injury af t er ac ut e reperf used inf arc t ion. Cir c ulat ion. 1996;94:3318–3326. 66. Kim RJ, F ieno DS, Parrish T B, et al. Relat ionship of MRI delay ed c ont rast enhanc ement t o irrev ersible injury , inf arc t age, and c ont rac t ile f unc t ion. Cir c ulat ion. 1999;100:1992–2002. 67. Kim WY , Danias PG, St uber M, et al. Coronary magnet ic resonanc e angiography f or t he det ec t ion of c oronary st enoses. New Engl J Med. 2001;345(26):1863–1869. 68. Kimura F , Sakai F , Sakomura Y , et al. Helic al CT f eat ures of arrhy t hmogenic right v ent ric ular c ardiomy opat hy . Radiogr aphic s. 2002;22:111–1124. 69. Klat t EC, Heit z DR. Cardiac met ast ases. Canc er . 1990;65: 1456–1459.

70. Knez A, Bec ker CR, Leber A, et al. Usef ulness of mult islic e spiral c omput ed t omography angiography f or det erminat ion of c oronary art ery st enoses. Am J Car diol. 2001;88:1191–1194. 71. Kondos GT , Hof f JA, Sev rukov A, et al. Elec t ron- beam t omography c oronary art ery c alc ium and c ardiac ev ent s: a 37- mont h f ollow - up of 5635 init ially asy mpt omat ic low - t o int ermediat e- risk adult s. Cir c ulat ion. 2003;107:2571–2576. 72. Kopp AF , Sc hroeder S, Kuet t ner A, et al. Non- inv asiv e c oronary angiography w it h high resolut ion mult idet ec t or- row c omput ed t omography . Result s in 102 pat ient s. Eur Hear t J. 2002;23: 1714–1725. 73. Koy ama Y , Moc hizuki T , Higaki J. Comput ed t omography assessment of my oc ardial perf usion, v iabilit y and f unc t ion. J Magn Reson Im aging. 2004;19:800–815. 74. Krait c hman DL, Sampat h S, Cast illo E, et al. Quant it at iv e isc hemia det ec t ion during c ardiac magnet ic resonanc e st ress t est ing by use of F ast HARP. Cir c ulat ion. 2003;107:2025–2030. 75. Kuet t ner A, Bec k T , Drosc h T , et al. Diagnost ic ac c urac y of noninv asiv e c oronary imaging using 16- det ec t or slic e spiral c omput ed t omography w it h 188 ms t emporal resolut ion. J Am Coll Car diol. 2005;45:123–127.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1532

9 - Heart and Pericardium 76. Kuet t ner A, Bec k T , Drosc h T , et al. Diagnost ic Ac c urac y of Noninv asiv e Coronary Imaging Using 16- Det ec t or Slic e Spiral Comput ed T omography w it h 188 ms T emporal Resolut ion. J Am Coll Car diol. 2005;45:123–127.

77. Kurat a A, Moc hizuki T , Koy ama Y , et al. My oc ardial perf usion imaging using adenosine t riphosphat e st ress mult i- slic e c omput ed t omography : alt ernat iv e t o st ress my oc ardial perf usion sc int igraphy . Cir c J. 2005;69:550–557. P.705 78. Lac omis JM, Wiggint on W, F uhrman C, et al. T hree- dimensional mult i—det ec t or row CT of t he lef t at rium and pulmonary v eins in at rial f ibrillat ion pat ient s undergoing radiof requenc y c at het er ablat ion. Radiogr aphic s. 2003;23:S35–S50. 79. Larson AC, Whit e RD, Laub G, et al. Self - gat ed c ardiac c ine MRI. Magn Reson Med. 2004;51:93–102. 80. Leber AW, Knez A, v on Ziegler F , et al. J Am Coll Car diol. 2005;46: 147–154. 81. Lee VS. Peric ardial Disease, Unit A11A. In: Cur r ent Pr ot oc ols in Magnet ic Resonanc e Im aging. New Y ork: John Wiley and Sons, 2001: A11.1.1–A11.1.14. 82. Lesc hka S, Alkadhi H, Plass A, et al. Ac c urac y of MSCT c oronary angiography w it h 64- slic e t ec hnology : f irst experienc e. Eur Hear t J. 2005;15:1482–1487. 83. Let a R, Carreras F , Alomar X, et al. Non- inv asiv e c oronary angiography w it h 16 mult idet ec t or- row spiral c omput ed t omography : a c omparat iv e st udy w it h inv asiv e c oronary angiography . Rev Esp Car diol. 2004;57:217–224. 84. Let himonnier F , F urber A, Morel O, et al. T hree- dimensional c oronary art ery MR imaging using prospec t iv e real- t ime respirat ory nav igat or and linear phase shif t proc essing: c omparison w it h c onv ent ional c oronary angiography . Magn Reson Im aging. 1999;17:1111–1120. 85. Li D, Kaushikkar S, Haac ke EM, et al. Coronary art eries: t hree- dimensional MR imaging w it h ret rospec t iv e respirat ory gat ing. Radiology . 1996;201(3):857–63. 86. Li D, Pasc hal CB, Haac ke EM, et al. Coronary art eries: t hree- dimensional MR imaging w it h f at sat urat ion and magnet izat ion t ransf er c ont rast . Radiology . 1993;187:401–406. 87. Mac eira AM, Joshi J, Prasad S, et al. Cardiov asc ular magnet ic resonanc e in c ardiac amy loidosis. Cir c ulat ion. 2004;111:186–193.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1533

9 - Heart and Pericardium 88. Mahnken AH, Kat oh M, Bruners P, et al. Ac ut e my oc ardial inf arc t ion: Assessment of lef t v ent ric ular f unc t ion w it h 16- det ec t or row spiral CT v ersus MR imaging—st udy in pigs. Radiology . 2005;236:112–117. 89. Mahnken AH, Wildberger JE, Koos R, et al. Mult islic e spiral c omput ed t omography of t he heart : t ec hnique, c urrent applic at ions, and perspec t iv e. Car diov asc Int er v ent Radiol. 2005;28:388–399. 90. Manning WJ, Li W, Edelman RR. A preliminary report c omparing magnet ic

resonanc e c oronary angiography w it h c onv ent ional angiography . N Engl J Med. 1993;328:828–832. 91. Mart usc elli E, Romagnoli A, D'Eliseo A, et al. Ac c urac y of t hin- slic e c omput ed t omography in t he det ec t ion of c oronary st enoses. Eur Hear t J. 2004;25:1043–1048. 92. Masui T , F inc k S, Higgins CB. Const ric t iv e peric ardit is and rest ric t iv e c ardiomy opat hy : ev aluat ion w it h MR imaging. Radiology . 1992;182:369–373. 93. Melt ser H, Kalaria VG. Cardiac t amponade. Cat het er Car diov asc Int er v . 2005;64:245–255. 94. Mollet N, Cadamat iri F , Krest in G, et al. Improv ing Diagnost ic Ac c urac y Wit h 16- Row Mult i- Slic e Comput ed T omography Coronary Angiography . J Am Coll Car diol. 2005;45:128–132. 95. Mollet NR, Cademart iri F , Krest in GP, et al. Improv ed diagnost ic ac c urac y w it h 16- row mult i- slic e c omput ed t omography c oronary angiography . J Am Coll Car diol. 2005;45:128–132. 96. Mollet NR, Cademart iri F , Nieman K, et al. Mult islic e spiral c omput ed t omography c oronary angiography in pat ient s w it h st able angina pec t oris. J Am Coll Car diol. 2004;43:2265–2270. 97. Moon JY , Chung N, Choi BW, et al. T he ut ilit y of mult i- det ec t or row spiral CT f or det ec t ion of c oronary art ery st enoses. Y onsei Med J. 2005; 28;46:86–94. 98. Nemet h MA, Mut hupillai R, Wilson JM, et al. Cardiac sarc oidosis det ec t ed by delay ed- hy perenhanc ement magnet ic resonanc e imaging. T ex Hear t Inst J. 2004;31:99–102. 99. Nieman K, Cademart iri F , Lemos PA, et al. Reliable noninv asiv e c oronary angiography w it h f ast submillimet er mult islic e spiral c omput ed t omography . Cir c ulat ion. 2002;106:2051–2054. 100. Nieman K, Oudkerk M, Rensing BJ, et al. Coronary angiography w it h mult islic e c omput ed t omography . Lanc et . 2001;357: 599–603.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1534

9 - Heart and Pericardium 101. Nieman K, Rensing BJ, v an Geuns RJ, et al. Usef ulness of mult islic e

c omput ed t omography f or det ec t ing obst ruc t iv e c oronary art ery disease. Am J Car diol. 2002;89:913–918. 102. Ohnsorge B, F lohr T , Bec ker C, et al. Cardiac imaging by means of elec t roc ardiographic ally gat ed mult isec t ion spiral CT : Init ial experienc e. Radiology . 2000;217:564–571. 103. Osman NF , Kerw in WS, Mc Veigh ER, et al. Cardiac mot ion t rac ing using CINE harmonic phase (HARP) magnet ic resonanc e imaging. Magn Reson Med. 1999;42:1048–1060. 104. Paul JF , Wart ski M, Caussin C, et al. Lat e def ec t on delay ed c ont rast enhanc ed mult i- det ec t or row CT sc ans in t he predic t ion of SPECT inf arc t size af t er reperf used ac ut e my oc ardial inf arc t ion: init ial experienc e. Radiology . 2005;236:485–489. 105. Pennell DJ, Bogren HG, Keegan J, et al. Assessment of c oronary art ery st enosis by magnet ic resonanc e imaging. Hear t . 1996;75(2): 127–133. 106. Pereles F S, Kapoor V, Carr JC, Simonet t i OP, Krupinski, Baskaran V, F inn JP. Usef ulness of segment ed t rueF ISP c ardiac pulse sequenc e in ev aluat ion of c ongenit al and ac quired adult c ardiac abnormalit ies. AJR Am J Roent genol. 2001;177:1155–1160. 107. Personal c ommunic at ion, Erdogan Cesmeli, PhD, Clinic al Researc h Sc ient ist , General Elec t ric Healt hc are. 108. Plein S, Jones T R, Ridgw ay JP, et al. T hree- dimensional c oronary MR angiography perf ormed w it h subjec t - spec if ic c ardiac ac quisit ion w indow s and mot ion- adapt ed respirat ory gat ing. AJR Am J Roent genol. 2003;180(2):505–512. 109. Post JC, v an Rossum AC, Hof man MBM, et al. Clinic al ut ilit y of t w odimensional magnet ic resonanc e angiography in det ec t ing c oronary art ery disease. Eur Hear t J. 1997;18:426–433. 110. Poust c hi- Amin M, Gut ierrez F R, Brow n JJ, et al. How t o plan and perf orm a c ardiac MR imaging examinat ion. Radiol Clin Nor t h Am . 2004;42:497–514. 111. Poust c hi- Amin M, Gut ierrez F R, Brow n JJ, et al. Perf orming Cardiac MR Imaging: An Ov erv iew . Magn Reson Im aging Clin N Am . 2003;11:1–18. 112. Pujadas S, Reddy GP, Weber O, et al. MR imaging assessment of c ardiac f unc t ion. J Magn Reson Im aging. 2004;19:789–799. 113. Rademakers F E, Bogaert J. Cardiac Anat omy . In: Bogaert J, Duerinc kx AJ, Rademakers F E, eds. Magnet ic r esonanc e im aging of t he hear t and gr eat v essels. Berlin: Springer- Verlag New Y ork, 1999: 29–38.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1535

9 - Heart and Pericardium 114. Raf f GL, Gallagher MJ, O'Neill WW, et al. Diagnost ic ac c urac y of noninv asiv e c oronary angiography using 64- slic e spiral c omput ed t omography . J Am Coll Car diol. 2005;46:552–557. 115. Regenf us M, Ropers D, Ac henbac h S, et al. Comparison of c ont rast enhanc ed breat h- hold and f ree- breat hing respirat ory - gat ed imaging in t hreedimensional magnet ic resonanc e c oronary angiography . Am J Car diol. 2002;90(7):725–730. 116. Rerkpat t anapipat P, Mazur W, Link KM, et al. Assessment of c ardiac f unc t ion w it h MR imaging. Magn Reson Im aging Clin N Am . 2003;11:67–80. 117. Ropers D, Baum U, Pohle K, et al. Det ec t ion of c oronary art ery st enoses

w it h t hin- slic e mult i- det ec t or row spiral c omput ed t omography and mult iplanar rec onst ruc t ion. Cir c ulat ion. 2003;107: 664–666. 118. Rumberger JA, Brundage BH, Rader DJ, et al. Elec t ron beam c omput ed t omographic c oronary c alc ium sc anning: A rev iew and guidelines f or use in asy mpt omat ic persons. May o Clin Pr oc . 1999;74:243–252. 119. Saad EB, Marrouc he NF , Saad CP, et al. Pulmonary v ein st enosis af t er c at het er ablat ion of at rial f ibrillat ion. Ann Int er n Med. 2003;138:634–638. 120. Sec ht em U, Pf lugf elder PW, Whit e RD, et al. Cine MRI: pot ent ial f or t he ev aluat ion of c ardiov asc ular f unc t ion. AJR Am J Roent genol. 1987;148:239–246. 121. Shaw LJ, Raggi P, Sc hist erman E, et al. Prognost ic v alue of c ardiac risk f ac t ors and c oronary art ery c alc ium sc reening f or all- c ause mort alit y . Radiology . 2003;228:826–833. 122. Simonet t i OP, F inn JP, Whit e RD, et al. Blac k blood T 2- w eight ed inv ersion- rec ov ery MR imaging of t he heart . Radiology . 1996;199:49–57. 123. Soulen RL, St ark DD, Higgins CB. Magnet ic resonanc e imaging of c onst ric t iv e peric ardial heart disease. Am J Car diol. 1985;55: 480–484. 124. Sprung K. Basic t ec hniques of c ardiac MR. Eur Radiol. 2005;15 Suppl 2:B10–B16. P.706 125. Sun JP, Asher CR, Y ang AS, et al. Clinic al and ec hoc ardiographic c harac t erist ic s of papillary f ibroelast omas: A ret rospec t iv e and prospec t iv e st udy in 162 pat ient s. Cir c ulat ion. 2001;103: 2687–2693. 126. T andri H, Bomma C, Calkins H, et al. Magnet ic resonanc e and c omput ed t omography imaging of arrhy t hmogenic right v ent ric ular dy splasia. J Magn Reson Im aging. 2004;19:848–858.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1536

9 - Heart and Pericardium 127. T andri H, Saranat han M, Rodriguez ER, et al. Noninv asiv e det ec t ion of my oc ardial f ibrosis in arrhy t hmogenic right v ent ric ular c ardiomy opat hy using delay ed- enhanc ement magnet ic resonanc e imaging. J Am Coll Car diol. 2005;45: 98–103. 128. T eraoka K, Hirano M, Ookubo H, et al. Delay ed c ont rast enhanc ement of MRI in hy pert rophic c ardiomy opat hy . Magn Reson Im aging. 2004;22:155–161. 129. T hompson LEJ, Kim RJ, Judd RM. Magnet ic resonanc e imaging f or t he assessment of my oc ardial v iabilit y . J Magn Reson Im aging. 2004;19:771–788. 130. T rabold T , Buc hgeist er M, Kut t ner A, et al. Est imat ion of radiat ion exposure in 16- det ec t or row c omput ed t omography of t he heart w it h ret rospec t iv e ECG- gat ing. Rof o. 2003;175: 1051–1055. 131. Villa A, Di Guglielmo L, Salerno J, et al. Arry t hmogenic dy splasia of t he right v ent ric le. Ev aluat ion of 7 c ases using c omput erized t omography . Radiol Med (T or ino). 1988;75:28–35. 132. Wagner S, Af f ermann W, Buser P, et al. Diagnost ic ac c urac y and

est imat ion of t he sev erit y of v alv ular regurgit at ion f rom t he signal v oid in c ine MR. Am Hear t J. 1989;118: 760–767. 133. Wang ZJ, Reddy GP, Got w ay MB, et al. CT and MR imaging of peric ardial disease. Radiogr aphic s. 2003;23:S167–S180. 134. Wexler L, Brundage B, Crouse J, et al. Coronary art ery c alc if ic at ion: pat hophy siology , epidemiology , imaging met hods and c linic al implic at ions. A st at ement f or healt h prof essionals f rom t he Americ an Heart Assoc iat ion Writ ing Group. Cir c ulat ion. 1996;94:1175–1192. 135. Whit e RD, T rohman RG, F lamm SD, et al. Right v ent ric ular arrhy t hmia in t he absenc e of arrhy t hmogenic dy splasia: MR imaging of my oc ardial abnormalit ies. Radiology . 1998;207: 743–751. 136. Woodard PK, Zheng J. Congenit al Heart Disease, Unit A10. In: Cur r ent Pr ot oc ols in Magnet ic Resonanc e Im aging. New Y ork: John Wiley and Sons, 2001: A10.1.1–A10.1.19. 137. Woodard PK. Comment ary on perc ut aneous c at het er ablat ion of at rial f ibrillat ion. Radiogr aphic s. 2003;23:48–50. 138. Woodard PK. Coronary MR Imaging T ec hniques. RSNA Cat egoric al Course in Diagnost ic Radiology Sy llabus: T horac ic Imaging—Chest and Cardiac 2001;67–73.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1537

9 - Heart and Pericardium 139. Woodard PK. MRI of Cardiac F unc t ion. Americ an Roent gen Ray Soc iet y ,

Cardiopulmonary Imaging, Cat egoric al Course Sy llabus, ed. Mc Adams HP, Reddy GP, 73–76. Present ed at t he Americ an Roent gen Ray Soc iet y , 105t h Annual Meet ing, New Orleans, LA May 15–20, 2005. 140. Woodard PK. Sc ienc e t o Prac t ic e: Can Mult idet ec t or Spiral CT be used t o Assess Lef t Vent ric ular F unc t ion? Radiology . 2005;236: 1–2. 141. Y oung AA, Cow an BR, T hrupp SF , et al. Lef t v ent ric ular mass and v olume: f ast c alc ulat ion w it h guide- point modeling on MR images. Radiology . 2000;216:597–602. 142. Zerhouni EA, Parish DM, Rogers WJ, et al. Human heart : t agging w it h MR imaging—a met hod f or noninv asiv e assessment of my oc ardial mot ion. Radiology . 1988;169:59–63.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

Thi s pa ge i s i ntenti ona l l y l eft bl a nk. Remove thi s text from the ma nua l templ a te i f you wa nt i t compl etel y bl a nk.

10 - Normal Abdominal and Pelvic Anatomy

1540

10 - Normal Abdominal and Pelvic Anatomy 15

10 - Normal Abdominal and Pelvic Anatomy Editors: Le e , Jose ph K. T. ; Sa ge l, Stua rt S. ; Sta nle y , Robe rt J. ; He ike n, Ja y P. Title : C ompute d Body Tomogra phy with MRI C orre la tion , 4th Edition Copy right В©2006 Lippinc ot t Williams & Wilkins > T able of Cont ent s > 10 - Normal Abdominal and Pelv ic Anat omy

10 Normal Abdominal and Pelvic Anatomy De nnis M. Ba lfe Bre tt Gra tz C hristine Pe te rson More t han ev er, a suc c essf ul radiologist must be a prac t ic al applied anat omist . T o bec ome ef f ec t iv e, t he radiologist has had t o assimilat e t he st andard anat omic inf ormat ion prov ided by c lassic al dissec t ions. T hat inf ormat ion is, how ev er, t o an inc reasing ext ent , inadequat e t o explain t he dy namic anat omic c hanges observ ed in pat hologic c ondit ions. Radiologist s c ont inue t o enric h and modif y st andard c onc ept ions of import ant st ruc t ures in t he abdomen and pelv is. Examples of t he import anc e of prec ise anat omic observ at ions abound in t he lit erat ure: t iny ext ensions of t he panc reat ic duc t ules w it hin a mass c an be t he sole dif f erent ial point in diagnosing t umef ac t iv e panc reat it is; t hin, nearly inv isible, f asc ial planes det ermine t he dist ribut ion of f luid c ollec t ions w it hin t he ret roperit oneum. T he import anc e of a t horough underst anding of human anat omy has grow n exponent ially as our abilit y t o image it has been ref ined. One of t he f irst princ iples of radiologic prac t ic e is t hat one must f irst rec ognize normal st ruc t ures, inc luding all of t heir normal v ariat ions, in order t o c onf ident ly diagnose w hat is abnormal. Now t hat imaging t ec hnology has adv anc ed t o t he point t hat subt le anat omic det ails c an be resolv ed and display ed, radiologist s must learn t o rec ognize t hem and t o underst and t heir behav ior in healt h and disease. T he most perv asiv e single c hange t o oc c ur in t he past dec ade has been t he abilit y t o render v olumet ric dat a set s in any user- def ined anat omic plane, in “ rubber- sheet ” c urv ed planes, or as images w it h a c omponent of t hreedimensional inf ormat ion c ont ent . Alt hough t his abilit y has been av ailable as a laborat ory t ool f or 20 y ears, t he abilit y t o c apt ure a c risp dat a set made of isot ropic v oxels, c oupled w it h t he int roduc t ion of user- f riendly sof t w are t ools,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1541

10 - Normal Abdominal and Pelvic Anatomy has made t hree- dimensional (3D) imaging a c linic al realit y . Ac c ordingly , alt hough many examples of normal abdominal and pelv ic anat omy are st ill w ell depic t ed on axial sec t ions, t here are many anat omic regions bet t er display ed

in ot her planes (149) or using v olumet ric display . Ac c ordingly , t his c hapt er w ill inc orporat e mult iplanar and v olumet ric renderings w henev er appropriat e. T he int ernal st ruc t ure of abdominal organs w ill be desc ribed, but only brief ly ; t he reader is ref erred t o more det ailed disc ussions of t he anat omy of eac h organ in t he c hapt er dealing w it h t hat spec if ic sy st em. In all c ases, part ic ular emphasis w ill be plac ed on t hose anat omic det ails t hat hav e prac t ic al applic at ions t o daily imaging proc edures and t o t hose regions in w hic h pat hologic proc esses are likely t o oc c ur.

ABDOMINAL ANATOMY Abdominal Wall T he rec t us abdominis musc les c ompose t he ant erior aspec t of t he abdominal w all (47) (F ig. 10- 1). T hey at t ac h t o t he f ront of t he xiphoid proc ess and t o c ost al c art ilages 5 t o 7. Ext ending inf eriorly as f lat , relat iv ely broad st ruc t ures, t hey at t ac h t o t he pubic sy mphy sis. Abov e t he umbilic us, t he rec t us musc les are surrounded by a st rong sheat h f ormed by t he aponeuroses of t he t hree ant erolat eral musc les (99): t he ant erior lay er is f ormed by f ibers of t he ext ernal oblique and by a port ion of t he f ibers of t he int ernal oblique. T he post erior lay er is f ormed c hief ly by f ibers f rom t he t ransv erses abdominis musc le, as w ell as some f rom t he int ernal oblique. How ev er, about 2 c m below t he umbilic us, t he post erior port ion of t he sheat h disappears, and f ibers of all P.708 t hree ant erolat eral musc le groups pass ant erior t o t he rec t us musc le (t he zone of anat omic t ransit ion is c alled t he ar c uat e line). T his arrangement has c linic al signif ic anc e in t hat rec t us sheat h hemat omas t hat oc c ur in t he upper abdomen are w ell c onf ined inside t he rec t us sheat h. Inf erior t o t he arc uat e line, how ev er, t hey c an esc ape int o t he easily expandable t ransv ersalis f asc ia, and c an dissec t post eriorly (int o t he spac e of Ret zius), ac ross t he midline, or lat erally int o t he f lank (F ig. 10- 2).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1542

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 1 Abdominal w all: rec t us musc le and sheat h. A: Sec t ion obt ained immediat ely c audal t o t he xiphoid show s t he paired rec t us abdominis musc les (r a), w hic h narrow medially t o at t ac h t o t he linea alba (ar r ow ). T hey at t ac h lat erally t o t he c ost al c art ilages (ar r ow heads) of t he f if t h t hrough sev ent h ribs. T he f at immediat ely post erior t o t hem lies in t he root of t he ligament um t eres (lt ). L, lef t hepat ic lobe. B: Sec t ion obt ained 5 c m c audal t o (A). T he rec t us musc les (r a) hav e t hinned and broadened. Lat erally , t hey lie on t he surf ac e of t he t ransv ersus abdominis musc le (ar r ow heads); medially , t he f at in t he root of t he ligament um t eres (lt ) apposes t heir post erior surf ac es. Post erior t o t hat , on t he right , is a port ion of t he great er oment um (go); on t he lef t is t he body of t he st omac h (ST ). L, liv er. C : In t his pat ient , f at t y inf ilt rat ion of bot h rec t us abdominis musc les (ra) allow s observ at ion of t he rec t us sheat h. At t his lev el (abov e t he arc uat e line), f ibers f rom t he t ransv ersus abdominis musc le (t r) and, v ariably , f rom t he int ernal oblique

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1543

10 - Normal Abdominal and Pelvic Anatomy musc le (io) pass post erior t o t he rec t us abdominis musc le t o f orm t he aponeurot ic post erior rec t us sheat h (open ar r ow s). F ibers of t he ext ernal oblique (eo) and int ernal oblique musc les blend t oget her (ar r ow ) t o c ourse ov er t he rec t us abdominis musc le, f orming t he ant erior rec t us sheat h. lt , f at in t he root of t he ligament um t eres.

Superf ic ial t o t he rec t us musc les, w it hin t he subc ut aneous f at , are t he superf ic ial epigast ric v eins, w hic h are generally largest on sec t ions t hrough t he pelv is (F ig. 10- 3). T he inf erior P.709 epigast ric v essels c ourse bet w een t he belly of t he rec t us musc le and t he post erior rec t us sheat h; on sec t ions below t he arc uat e line, t hey lie bet w een t he rec t us musc le and t he t ransv ersalis f asc ia. On c onsec ut iv ely inf erior sec t ions, t he inf erior epigast ric v essels c ourse lat erally w it hin t he lat eral umbilic al f old, w hic h marks t he medial aspec t of t he deep inguinal ring. T he v essels also f orm t he lat eral boundary of t he inguinal t riangle (t he Hasselbac h t riangle), t he medial boundary of w hic h is t he edge of t he rec t us musc le, and t he inf erior boundary of w hic h is t he pubic bone. Coronal and sagit t al images best depic t t he origin and c ourse of t he inf erior epigast ric art ery and v ein (see F ig. 10- 3).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1544

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 2 Rec t us sheat h. A: Sec t ion obt ained abov e t he arc uat e line in a pat ient w it h lef t rec t us sheat h hemat oma (H). Not e t hat t he hemat oma is w ell c onf ined bet w een t he aponeurot ic f ibers of t he ext ernal oblique (ar r ow ) ant eriorly and t he t ransv ersus abdominis (open ar r ow ) post eriorly . B: Sec t ion obt ained below t he arc uat e line show s t hat only t he ant erior aponeurosis (ar r ow ) persist s. Post eriorly , t he hemat oma is unc onf ined, and ext ends (c ur v ed ar r ow ) int o t he ext raperit oneal spac e. Not e t riangular f at surrounding t he urac hus (U). C : Sagit t al image in anot her pat ient w it h ext ensiv e rec t us sheat h hemat oma show s t hat post erior lay er of t he rec t us sheat h (ar r ow heads) c onf ines t he hemat oma t o t he lev el of t he arc uat e line. Caudal t o t his, t he hemat oma is f ree t o ext end (c ur v ed ar r ow ) int o t he prev esic al f at .

T he ant erolat eral abdominal w all is made up of t hree paired musc les: f rom superf ic ial t o deep, t hey are t he ext ernal oblique, int ernal oblique, and t ransv erses abdominis. As not ed abov e, t he medial aspec t of all t hree musc les is an aponeurosis, w hic h c ont ribut es t o t he f ormat ion of t he rec t us sheat h. T he low er part of t he ext ernal oblique aponeurosis f orms t he inguinal ligament .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1545

10 - Normal Abdominal and Pelvic Anatomy

Magnet ic resonanc e imaging (MRI) has been used ef f ec t iv ely t o det ec t st rains of t he ant erolat eral musc ulat ure (23). T he major musc les of t he post erior abdominal w all are, medially , t he erec t or spinae musc les and, lat erally t he lat issimus dorsi (F ig. 10- 4). T he erec t or spinae (or sac rospinalis) musc le is really a group of t hree musc les t hat c annot be dist inguished using st andard imaging t ec hniques: f rom lat eral t o medial, t hey are t he ilioc ost alis, t he longissimus, and t he spinalis. Combined, t hese musc les are narrow at sac ral lev els but broad in t he t horac olumbar region (54). T he post erolat eral surf ac e of t he ext ernal oblique musc le is c ov ered by t he lat issimus dorsi, exc ept inf eriorly , w here t he t w o musc les at t ac h in separat e loc at ions t o t he iliac P.710 P.711 P.712 P.713 c rest . T he ext ernal oblique musc le at t ac hes ant eriorly , w hereas t he t endon of t he lat issimus dorsi passes post eriorly . T his exposes a small t riangle of int ernal oblique musc ulat ure just abov e t he iliac c rest . T his inf erior lumbar t riangle (also know n as t he Pet it t r iangle) (F ig. 10- 5) is t he sit e of spont aneous lumbar hernias (11). T his area is import ant t o sc rut inize in pat ient s w it h highspeed v ehic ular t rauma, part ic ularly in pat ient s rest rained by seat belt s (70) (F ig. 10- 6).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

10 - Normal Abdominal and Pelvic Anatomy

Computed Body Tomography with MRI Correlation , 4th Edition

1546

© 2017 Enter your company name

1547

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 3 Superf ic ial epigast ric v essels. A: Sec t ion t hrough t he pelv ic inlet show s t he superf ic ial epigast ric v ein (ar r ow head) w it hin t he subc ut aneous f at ant erior t o t he rec t us abdominis musc le (RE). T his v ein is part of an ext ensiv e net w ork t hat c onnec t s t o t he t horac oepigast ric sy st em, t he inf erior epigast ric sy st em, and t he paraumbilic al v enous plexus. Just deep t o t he rec t us abdominis musc le is t he epigast ric art ery (ea) and v ein. B: T he epigast ric v essels (ea) 16 mm inf erior t o (A) lie c lose t o t he v asa def erent ia (ar r ow s) in men (t he round ligament oc c upies t his posit ion in w omen). Ar r ow head, superf ic ial epigast ric v ein. C : T he epigast ric v essels (ea) 16 mm inf erior t o (B), near t heir sit e of origin f rom t he ext ernal iliac art ery and v ein, c ross t he v asa def erent ia (ar r ow ). Nearer t he midline is t he medial umbilic al ligament (ul), t he oblit erat ed remnant of t he umbilic al art ery , c oursing ant erior t o t he bladder (BL). Ar r ow head, superf ic ial epigast ric v ein. D: Coronal v iew of t he ant erior abdominal w all show s t he serpent ine c ourse of t he superf ic ial epigast ric v eins (ar r ow s). E: Coronal t hic k- slab MIP show ing t he relat ionship of t he inf erior epigast ric art eries (1) w it h major superf ic ial branc hes of t he ext ernal iliac art ery . T he inf erior epigast ric art ery arises just abov e t he inguinal ligament , w hereas t he superf ic ial c irc umf lex iliac art ery (2) usually arises f rom t he c ommon f emoral art ery just c audal t o t he inguinal ligament . T he proximal inf erior epigast ric art ery giv es rise t o t he pubic art ery (3), w hic h c ourses c audally t ow ards t he pubis (P); inf eriorly , it f orms an anast amosis w it h t he obt urat or art ery . T he c ommon f emoral art ery (5) bif urc at es int o t he superf ic ial f emoral (6) and deep f emoral (7) art eries. T he lat t er giv es rise t o a large lat eral branc h, t he lat eral c irc umf lex f emoral art ery (4). F : Sagit t al t hic k- slab maximum- int ensit y projec t ions show s t he c ourse of t he inf erior epigast ric art ery (ar r ow ) on t he post erior border of t he rec t us musc le (RM); superiorly , it pierc es t he t ransv ersalis f asc ia (open ar r ow ) just below t he arc uat e line and asc ends bet w een t he rec t us musc le and it s sheat h. G: Oblique perspec t iv e v olume rendered image show s t he origin of t he lef t inf erior epigast ric art ery (ar r ow ) f rom t he ext ernal iliac art ery (ea).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1548

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 4 Post erior abdominal w all. A: Sec t ion at t he lev el of t he renal hilus show s t he bulky erec t or spinae musc les groups (es) adjac ent t o t he v ert ebral t ransv erse proc ess. Ov erly ing t he ribs on t he post erolat eral surf ac e of t he body are t he serrat us post erior inf erior (spi) and lat issimus dorsi (ld) musc les. T he lat t er giv es rise t o a t ough f asc ial lay er, t he t horac olumbar f asc ia (t lf ). B: Sec t ion obt ained 16 mm c audal t o (A). T he superior lumbar spac e (sls), here c ont aining a small amount of herniat ed f at , lies bet w een t he int erc ost al musc les (ic ) and t he lat issimus dorsi musc le (ld) and t horac olumbar f asc ia (t lf ) just lat eral t o t he serrat us post erior inf erior (spi) musc le band. es, Erec t or spinae.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1549

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 5 Inf erior lumbar t riangle (t he Pet it t riangle): normal anat omy . A: Sec t ion t hrough t he quadrat us lumborum musc le (ql) show s t he band- like lat issimus dorsi musc le (ld) c ov ering t he post erior aspec t of t he post erior abdominal w all, c omprised of t he t ransv ersus abdominis (t a), int ernal oblique (io), and ext ernal oblique (eo) musc les. T he t horac olumbar f asc ia (t lf ), an ext ension of t he lat issimus dorsi musc le, ext ends post eromedially t o c ov er t he surf ac e of t he quadrat us lumborum and erec t or spinae (es) musc les. B: Sec t ion obt ained 7 mm c audal t o (A) show s t hat t he lat issimus dorsi (ld) musc le has passed post eromedially w it h respec t t o t he post erolat eral abdominal musc ulat ure [t ransv ersus abdominis (t a), int ernal oblique (io), and ext ernal oblique (eo) musc les] t o c reat e a def ec t , t he inf erior lumbar spac e (ils) t hrough w hic h lumbar hernias c an prot rude. ql, Quadrat us lumborum musc le; es, erec t or spinae; t lf , t horac olumbar f asc ia. C : Coronal ref ormat ion

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1550

10 - Normal Abdominal and Pelvic Anatomy in anot her pat ient show s t he f at - c ont aining inf erior lumbar t riangle (ast er isk) bet w een t he quadrat us lumborum musc le (ql) medially and t he t hin f ibers of t he t ransv ersus abdominis musc le (ar r ow ) lat erally . D: Oblique c oronal ref ormat ion highlight s t he f at - c ont aining spac e (ast er isk) bet w een t he abdominal w all musc ulat ure (c hief ly c omposed of t he ext ernal oblique musc le (eo) and t he quadrat us lumborum musc le (ql).

F igure 10- 6 T raumat ic lumbar hernia. A: Axial sec t ion obt ained abov e t he iliac c rest in a pat ient inv olv ed in high- speed mot or v ehic le c ollision w hile w earing a lap belt . T here is marked separat ion bet w een t he lat eral abdominal w all musc ulat ure (eo) and t he lat issimus dorsi musc le (ast er isk), ly ing just lat eral t o t he quadrat us lumborum (ql). B: Coronal sec t ion in t he same pat ient show s herniat ion of small int est ine (c ur v ed ar r ow ) t hrough t he t raumat ic hernia.

T here is, likew ise, a relat iv e point of w eakness in t he aponeuroses of t he t ransv ersus abdominis and int ernal oblique musc les just lat eral t o t he rec t us abdominis musc le near t he lev el of t he arc uat e line. T his is t he c lassic sit e f or a Spigelian hernia (126). T hese hernias, w hen small, are f requent ly c linic ally inapparent , bec ause t hey are c onf ined deep t o t he st rong ext ernal oblique musc le (F ig. 10- 7). T he inguinal c anal is t he major st ruc t ure passing out of t he abdomen, t hrough t he lat eral w all musc ulat ure. In men, t he c anal c ont ains t he spermat ic c ord; in w omen, t he round ligament . T he deep inguinal ring is a slit - like opening in t he t ransv ersalis f asc ia. As it s c ont ent s pass t hrough t he inguinal c anal, t hey are c ov ered by f ibers of t he int ernal oblique musc le, w hic h, inf eriorly , f orm t he c remast er musc le. F inally , t hey pass inf eromedially t hrough t he aponeurot ic part of t he ext ernal oblique at t he superf ic ial inguinal ring. Indirec t inguinal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1551

10 - Normal Abdominal and Pelvic Anatomy

hernias (w hic h are by f ar t he more c ommon) essent ially f ollow t he pat h of t he inguinal c ont ent s and t heref ore begin just lat eral t o t he inf erior epigast ric v essels (F ig. 10- 8). Direc t inguinal hernias prot rude t hrough def ec t s in t he t ransv ersalis f asc ia t hat c omprises t he f loor of t he inguinal c anal; t hey oc c ur medial t o t he inf erior epigast ric v essels (77,150). Comput ed t omography (CT ) is usef ul in depic t ing abdominal w all hernias, w hic h, in many c ases, are dif f ic ult t o ev aluat e c linic ally bec ause of obesit y or sc arring f rom prev ious surgery . Sc ans perf ormed w it h t he pat ient in a lat eral dec ubit us posit ion, or during a Valsalv a maneuv er, may demonst rat e hernias t hat are not w ell depic t ed during st andard imaging t ec hniques (1,33,52,65).

F igure 10- 7 Spigelian hernia. T ransv erse c omput ed t omography sec t ion obt ained t hrough t he midabdomen show s herniat ion of great er oment um (H) t hrough a def ec t immediat ely lat eral t o t he rec t us abdominis musc le (RA). T his is t he c lassic loc at ion f or a Spigelian hernia.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

10 - Normal Abdominal and Pelvic Anatomy

Computed Body Tomography with MRI Correlation , 4th Edition

1552

© 2017 Enter your company name

1553

10 - Normal Abdominal and Pelvic Anatomy F igure 10- 8 T he inguinal c anal. A: Axial image obt ained in a normal pat ient

show s t he inf erior epigast ric art ery (ar r ow head) arising f rom t he ext ernal iliac (ia) at t he lev el of t he int ernal inguinal ring. T he deep c irc umf lex iliac art ery (dc i) arises at nearly t he same lev el. B: Axial image 5 mm inf erior t o (A) show s t he spermat ic c ord (ar r ow ) ent ering t he right inguinal c anal. C : Axial image 5 mm inf erior t o (B) show s t he right spermat ic c ord (ar r ow ) c oursing medially w it hin t he inguinal c anal, behind f ibers of t he int ernal oblique musc le (iom). D: Axial image 5 mm inf erior t o (C ) show s t he spermat ic c ord (ar r ow ) emerging f rom t he ext ernal inguinal ring t o lie just lat eral t o t he rec t us abdominis musc le (ra). E: Oblique c oronal ref ormat t ed image show s t he inf erior epigast ric art ery (ar r ow head) arising f rom t he ext ernal iliac (ei); t he inf erior epigast ric giv es rise t o t he c remast eric art ery (open ar r ow ) w hic h ac c ompanies t he v as def erens (v as) int o t he inguinal c anal. F : Sagit t al image in anot her subjec t w it h a direc t inguinal hernia show s t he inf erior epigast ric art ery (ar r ow ) w hic h marks t he lat eral boundary of t he Hasselbac h t riangle. T he origin of t he inf erior epigast ric art ery and it s pubic branc h (open ar r ow ) marks t he posit ion of t he int ernal inguinal ring. In t his pat ient , an int est inal loop (i) prot rudes t hrough a def ec t in t he t ransv ersalis f asc ia (ar r ow heads) t o ent er t he inguinal c anal. G: Sagit t al image obt ained 10 mm medial t o (E) show s int est inal loop (i) ext ending t ow ard t he f at w it hin t he sc rot um (s).

P.714 P.715

Diaphragm, Crura, and Arcuate Ligaments T he diaphragm is a large, dome- shaped musc le t hat inc omplet ely div ides t he t horax f rom t he abdomen. It s f ibers t ake origin f rom t he st ernum ant eriorly , f rom t he medial surf ac es of t he low er ribs ant erolat erally , and f rom t he upper lumbar v ert ebral bodies post eriorly . T hey insert superomedially on an aponeurosis (t he c ent ral t endon), t he t hinnest port ion of t he diaphragm, w hic h is shaped like an inv ert ed “ V” on t ransaxial sec t ions. T he apex of t he c ent ral t endon lies just ant erior t o t he inf erior v ena c av a; it s limbs desc end post erolat erally t o enc lose t he v ena c av a on t he right and pass ant erior t o t he esophageal hiat us on t he lef t . It is t hrough t he esophageal hiat us t hat hiat al hernias (as w ell as asc it es, or panc reat ic f luid c ollec t ions) c an ext end int o t he post erior mediast inum (84) (F ig. 10- 9). T he c ross- sec t ional appearanc e of t he relat iv ely short ant erior f ibers of t he diaphragm depends on t he pat ient 's body habit us and result ant posit ion of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1554

10 - Normal Abdominal and Pelvic Anatomy middle leaf let of t he diaphragm relat iv e t o t he st ernum. Normally , t he c ent ral

t endon lies 2 t o 3 c m c ephalic t o t he xiphoid proc ess, so t hat c ross- sec t ional images of t he diaphragm show a t hin sof t t issue st ripe c rossing roughly parallel t o t he ant erior body w all. A more c audally posit ioned c ent ral t endon c an produc e a c onf using image (40), result ing in an ant erior pseudomass c lose t o t he xiphoid proc ess (F ig. 10- 10). In t his sit uat ion, ant erior diaphragmat ic f ibers c ourse ant erior and lat eral t o t heir origin on c ost al c art ilage and enc lose abdominal f at , f orming an arc h ant erior t o liv er and heart . T his orient at ion produc es f an- like sof t t issue st ripes projec t ing f rom t he base of t he heart t o t he ant erior body w all. If t he c ent ral t endon and xiphoid are at t he same lev el, most of t he ant erior diaphragm w ill be imaged on a single slic e and w ill appear as a v ery broad sof t t issue band. T his port ion of t he diaphragm is not opt imally imaged in t he axial plane; t hese c onf using images c an easily be resolv ed using images ref ormat t ed in sagit t al or c oronal planes. In most pat ient s, t he lat eral and post erior port ions of t he diaphragm are perpendic ular t o t he plane of axial sec t ion and are display ed as t hin sof t t issue st ripes separat ing lung parenc hy ma f rom abdominal f at . Suspended inspirat ion, part ic ularly in pat ient s w ho perf orm a Valsalv a maneuv er, allow s t he musc ular slips of t he diaphragm t o relax and bec ome f olded near t heir c ost al insert ions. T hey are t hen display ed as disc ret e, t hic k, somet imes nodular sof t t issue densit ies, w hic h may indent t he liv er, st omac h, c olon, or spleen, f orming ac c essory f issures or pseudot umors. T his is c ommonly observ ed in elderly indiv iduals (118) (F igs. 10- 11 and 10- 12). T hese inf oldings c an be dist inguished f rom pat hologic nodular densit ies by not ing t heir c ont inuit y w it h t he diaphragm and t heir separat ion f rom abdominal solid and hollow v isc era by subdiaphragmat ic f at . In problemat ic c ases, repeat imaging in expirat ion w ill c onf irm t heir ident it y as diaphragmat ic st ruc t ures (5,117). T he lumbar, or post erior, port ion of t he diaphragm arises f rom t he c rura and t he medial and lat eral arc uat e ligament s. T he right and lef t diaphragmat ic c rura t ake origin f rom t he ant erolat eral surf ac e of t he f irst t hree right and f irst t w o lef t lumbar v ert ebral bodies. T hey unit e ant eriorly P.716 P.717 P.718 t o f orm t he median arc uat e ligament , surrounding t he aort a immediat ely c ephalic t o t he c eliac t runk (110). T his ligament c an be imaged as a t hin sof t t issue st ripe c rossing t he aort a; in some c ases, it c an produc e def ormit y of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1555

10 - Normal Abdominal and Pelvic Anatomy t he c eliac t runk (F ig. 10- 13) (134). T he right c rus is larger and originat es low er t han t he lef t ; it ext ends t o t he lef t of midline. As t he c rura c ont inue

upw ard, t he right c rus div ides t o enc lose t he esophagus w it hin t he esophageal hiat us. As t he esophagus ent ers t he st omac h, bot h st ruc t ures are relat iv ely f irmly t et hered t o t he f issure f or t he ligamant um v enosum P.719 by t he gast rohepat ic ligament . As a result , a port ion of t he st omac h w all runs in a t ransv erse plane, and t heref ore appears t hic ker t han t he rest of t he st omac h on t ransv erse sec t ions (28). T his “ pseudomass” has been not ed in 25% t o 30% of normal subjec t s (82,138). At t he lev el of t he esophageal hiat us, t he f ibers of t he right c rus ext end almost direc t ly ant eriorly , and t he most ant erior port ion may hav e a bulbous or nodular appearanc e t hat mimic s lef t gast ric adenopat hy . (F ig. 10- 14). T he smaller lef t c rus remains apposed t o t he aort a at t his lev el. T he post erior aspec t s of bot h c rura lie against t he pleural spac es.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1556

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 9 T he esophageal hiat us. A: Sec t ion obt ained immediat ely abov e t he gast roesophageal junc t ion show s t he right diaphragmat ic c rus (rc ) adjac ent t o t he f at in t he f issure f or t he ligament um v enosum (f lv ). T he esophagus (E) passes bet w een t he aort a (A) and right c rus as it c ourses f rom middle mediast inum int o t he abdomen. B: Sec t ion obt ained 7 mm c audal t o (A) show s t he abdominal segment of t he esophagus (gej) as it joins t he st omac h (ST ) bet w een t he right (rc ) and lef t (lc ) c rura. Of inc ident al not e is an ac c essory lef t hepat ic art ery (alh), arising as a branc h of t he lef t gast ric art ery and c oursing t hrough t he f issure f or t he ligament um v enosum (f lv ). C : Sec t ion obt ained 7 mm c audal t o (B) show s approximat ion of t he right c rus (rc ) t o t he lef t (lc ), ef f ec t iv ely c losing t he esophageal hiat us. T he lef t c rus of t he diaphragm remains in c ont ac t w it h t he ant erior surf ac e of t he aort a (A). Not e t hat t here has been an inc rease in t he v olume of f at w it hin t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1557

10 - Normal Abdominal and Pelvic Anatomy gast rohepat ic ligament (ghl) adjac ent t o t he lesser c urv at ure of t he st omac h (ST ). lga, Lef t gast ric art ery ; gej, gast roesophageal junc t ion. D: Coronal ref ormat t ed image in anot her pat ient depic t s t he esophagus (E) c oursing obliquely f rom t he t horax int o t he abdominal c av it y . F ibers of t he right diaphragmat ic c rus (r c ) sw eep t o t he lef t t o enc lose t he esophagus at t he hiat us. Ar r ow , lef t leaf of t he diaphragm; ast er isk, paraesophageal ly mph node.

F igure 10- 10 Appearanc e of ant erior leaf let s of t he diaphragm. A: Pseudomass c aused by ant erior diaphragm. In t his pat ient , t he c ent ral t endon of t he diaphragm is at a lev el c lose t o t he xiphoid proc ess (X). In t his set t ing, t he broad musc les of t he ant erior diaphragm c ourse in t he same plane as t he sc an sec t ion, produc ing a pseudomass (M?) adjac ent t o t he peric ardium. B: In t his indiv idual, a port ion of t he ant erior lef t hemidiaphragm (ar r ow ) is imaged t angent ially , simulat ing a mass. T he f ibers c omprising t he st ernal origin of t he diaphragm (open ar r ow ) c reat e a t riangular sof t t issue densit y . C : Ref ormat t ed sagit t al image near t he midline show s t he f ibers originat ing f rom t he st ernum, and ext ending post eriorly t o join t he c ent ral t endon (ar r ow heads).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1558

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 11 Diaphragmat ic musc le mimic king liv er lesion. A: Comput ed t omography sec t ion obt ained at a lev el inf erior t o t he dome of t he diaphragm show s a peripheral band- like low - at t enuat ion def ec t (ar r ow ). B: Magnet ic resonanc e imaging sec t ion in t he same loc at ion show s a low - int ensit y st ruc t ure (ar r ow ) at t he liv er periphery . Serial images demonst rat ed it s assoc iat ion w it h a rib.

F igure 10- 12 Splenic indent at ion f rom diaphragmat ic slip. A: Sec t ion near t he gast roesophageal junc t ion show s a f at - c ont aining not c h (ar r ow ) on t he post erolat eral aspec t of t he spleen (S). A, Aort a; ST , st omac h; L, liv er. B: Sec t ion obt ained 5 mm inf erior t o (A) show s t he sof t t issue at t enuat ion

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1559

10 - Normal Abdominal and Pelvic Anatomy

diaphragmat ic slip passing t hrough t he splenic not c h as it bec omes c ont inuous w it h t he diaphragm. S, Spleen; A, aort a; ST , st omac h; L, liv er.

F igure 10- 13 Median arc uat e ligament . A: Axial sec t ion obt ained just abov e t he c eliac t runk show s t he median arc uat e ligament (ar r ow ) immediat ely ant erior t o t he aort a, ext ending bet w een t he lef t (lc ) and right c rus (rc ). B: Ref ormat t ed sagit t al image obt ained at end expirat ion show s t he proximit y of t he c eliac t runk (c t ) w it h t he median arc uat e ligament (ar r ow ). In some pat ient s, end- expirat ory imaging produc es apparent oc c lusion of t he proximal c eliac art ery .

F igure 10- 14 Ret roc rural spac e. A: Sec t ion obt ained at t he gast roesophageal junc t ion show s t he abdominal segment of t he esophagus (E) passing obliquely t hrough t he hiat us bet w een t he right (rc ) and lef t c rura (lc ). T he ret roc rural spac e def ined by t he c rural f ibers is a c ont inuat ion of t he mediast inum. It c ont ains t he aort a (A); t he azy gous (az) v ein, w hic h on t his sec t ion rec eiv es

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1560

10 - Normal Abdominal and Pelvic Anatomy

an int erc ost al v ein (ar r ow ); t he hemiazy gous (haz) v ein; a v ariable amount of f at ; t he t horac ic duc t and ly mph nodes (ar r ow head); and part of t he sy mpat het ic t runk. At t his lev el and t he next , t here is c ont inuit y bet w een t he ret roc rural spac e and t he abdominal c ont ent s, namely , t he esophagus and gast rohepat ic ligament (ghl). B: Sec t ion obt ained 16 mm below (A). T he lef t (lc ) and right c rura (rc ) hav e reapposed below t he esophageal hiat us. A small bulbous projec t ion f rom t he right c rus (open ar r ow ) projec t s int o t he region of t he gast rohepat ic ligament ; t his c an mimic a node if it s c ont inuit y w it h t he remainder of t he c rus is not apprec iat ed.

T he t w o c rura enc lose a ret roc rural spac e ant erior t o t he upper lumbar v ert ebral bodies (127). T he aort a is t he major c omponent of t his spac e, but t he t horac ic duc t and azy gos/hemiazy gos v eins also lie w it hin it . T he c ist erna c hy li is v ery f requent ly depic t ed as a bulbous st ruc t ure of near w at er at t enuat ion on t he right side of t he ret roc rural spac e (F ig. 10- 15) (46,112). T he ret roc rural spac e c onnec t s t he post erior mediast inum w it h t he abdominal ret roperit oneum; pat hologic proc esses in t his spac e are c onf ined on c ephalic sec t ions near t he diaphragm, but below t he median arc uat e ligament , may esc ape ant eriorly int o t he spac e ant erior t o t he great v essels. Caudal t o t he median arc uat e ligament , t he v ert ebral origins of t he diaphragm are seen as f usif orm sof t t issue densit ies ly ing on t he lat eral surf ac e of t he v ert ebral body ant erior t o t he psoas musc les. On more c audal sec t ions, t he c rura (most c ommonly t he larger right c rus) c an be v ery nodular in appearanc e, so t hat t hey mimic paraaort ic ly mph nodes (155). T he medial and lat eral arc uat e ligament s c ourse ov er t he psoas and quadrat us lumborum musc les t o f use w it h t he diaphragm (99,109). T he medial arc uat e ligament ext ends f rom t he lat eral margin of t he lumbar spine (L1) v ert ebral body t o t he t ransv erse proc ess of L1. T he lat eral arc uat e ligament originat es f rom t he t ransv erse proc ess of t he L1 v ert ebral body and insert s on t he t w elf t h rib. In about 5% of normal subjec t s, t he lat eral arc uat e ligament c an appear v ery nodular (131), and know ledge of it s appearanc e is helpf ul t o av oid c onf using it w it h pat hology (F ig. 10- 16). Hernias t end t o oc c ur at spec if ic plac es in t he diaphragmat ic surf ac e. Ant erior (Morgagni) hernias are ret rost ernal or posit ioned just lat eral t o t he xiphoid on eit her side (34); t heir loc at ion may be t he result of w eakness at t he sit e of penet rat ion of t he diaphragm by t he superior epigast ric v essels. Post erior (Boc hdalek) hernias represent inc omplet e c losure of t he pleuroperit oneal c anal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1561

10 - Normal Abdominal and Pelvic Anatomy

(41). T hey are depic t ed on c ross- sec t ional imaging w it h higher t han expec t ed f requenc y and are at least as likely on t he right as P.720 P.721 on t he lef t (97) Bot h c an c ont ain abdominal f at or port ions of subdiaphragmat ic v isc era.

F igure 10- 15 Cist erna c hy li. A: T 2- w eight ed magnet ic resonanc e axial image t hrough t he t horac olumbar junc t ion show s a large f luid- f illed st ruc t ure (C) just t o t he right of t he aort a (A) and immediat ely ant erior t o t he hemiazy gos v ein (ar r ow ). B: Sagit t al image in t he same subjec t show s t he junc t ion of t he dilat ed right lumbar t runk (ar r ow head) w it h t he c ist erna c hy li (C).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1562

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 16 Lat eral arc uat e ligament . A– D: Serial sec t ions beginning just inf erior t o t he renal hilus show t he lat eral arc uat e ligament (ar r ow ) ext ending f rom a lat eral posit ion near it s at t ac hment t o t he rib (in [A]) t o a more post erior posit ion immediat ely behind t he right kidney (RK) (in [D]). On t he inf erior segment s, t he ligament is t hic ker and broader t han at it s at t ac hment , and mimic s a mass. L, Liv er.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1563

10 - Normal Abdominal and Pelvic Anatomy F igure 10- 17 T raumat ic rupt ure of t he diaphragm. A: Axial sec t ion t hrough t he low er t horax in a pat ient inv olv ed in a mot or v ehic le c ollision show s a large lef t pneumot horax (Pt x). T he f undus of t he st omac h (ST ) lies oc c upies t he post erior hemit horax at t his lev el. B: Ref ormat t ed c oronal image in t he same pat ient show s large gap (bet w een ar r ow s) in t he lef t hemidiaphragm, w it h prot rusion of t he gast ric f undus (c ur v ed ar r ow ) int o t he t horax t hrough t he def ec t . ST , st omac h.

Cross- sec t ional imaging has prov ed usef ul in ev aluat ing pat ient s w it h t raumat ic injuries t o t he diaphragm (16,17,76,98,100,124). In v ehic ular t rauma, t he t ears t end t o c lust er about t he junc t ion bet w een t he c ent ral t endon and t he musc ular port ion of t he diaphragm and are muc h more c ommon on t he lef t . T he diagnosis is import ant , c hief ly bec ause of t he morbidit y of delay ed v isc eral herniat ion w it h st rangulat ion; mult idet ec t or CT (MDCT ) w it h sagit t al and c oronal rec onst ruc t ion has posit iv e and negat iv e predic t iv e v alues of about 80% (F ig. 10- 17).

Intraperitoneal Organs Embryology T he logic underly ing t he anat omic dist ribut ion of normal int raabdominal v isc era and t he dist ribut ion of pat hologic proc esses arising f rom t hem is relat ed t o t heir embry ology . Spec if ic ally , an underst anding of t he embry ology of t he mesent eries and t he grow t h and dev elopment of int ramesent eric organs prov ides a basis f or underst anding t he c omplex nat ure of t he perit oneal spac es in t he upper abdomen, t he f ormat ion of t he abdominal ligament s (w hic h play a c rit ic al role in def ining t he c ourse of pat hologic proc esses), and t he genesis of t he ant erior pararenal spac e. Moreov er, t he dist ribut ion and pat t erns of ext ension of f luid c ollec t ions in t he ret roperit oneum are explained by t he same embry ologic proc esses. Embry ologic ally , t he gut dev elops f rom t he y olk sac ; it is suspended f rom t he ant erior and post erior body w alls by v ent ral and dorsal mesent eries, w hic h f orm t he lat eral boundaries of t he dev eloping aliment ary t ube. Early in f et al lif e, import ant organs dev elop in t he mesent eries of t he c audal part of t he f oregut . T he dorsal mesogast rium is t he sit e of t he dev eloping spleen and dorsal panc reas, w hereas t he liv er expands w it hin t he v ent ral mesogast rium, along w it h t he v ent ral panc reas (F ig. 10- 18). Major f et al art eries c ourse

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1564

10 - Normal Abdominal and Pelvic Anatomy ant eriorly t hrough t he dorsal mesent eries f rom t he aort a t o supply t he dev eloping gut and it s new ly dev eloping organs. As t he liv er grow s, t he v ent ral mesogast rium t hins great ly ; t he ant erior part of it , w hic h in t he adult c ont ains t he oblit erat ed umbilic al v ein (ligament um t eres), bec omes t he f alc if orm ligament . In t he adult , t his st ruc t ure is depic t ed as a midline t riangular f at c ollec t ion c ont aining a f ibrous c ord t hat is t he remnant of t he oblit erat ed umbilic al v ein. It ent ers t he liv er subst anc e at t he f issure f or t he ligament um t eres, f orming an inc omplet e separat ion bet w een t he medial and lat eral segment s of t he lef t hepat ic lobe. T he dorsal part of t he v ent ral mesogast rium (bet w een t he liv er and t he gut ) also t hins apprec iably t o f orm t he lesser oment um. In t he adult , t his st ruc t ure, w it h it s ac c ompany ing f at , st ret c hes bet w een t he lesser c urv at ure of t he st omac h and t he f issure f or t he ligament um v enosum, inc omplet ely separat ing t he c audat e lobe f rom t he lef t lat eral segment . Wit hin t his

gast rohepat ic ligament are t he lef t gast ric art ery and c oronary v ein, and part of t he c eliac ly mph node c hain (6,12) (F ig. 10- 19). In some pat ient s, a port ion of t he c audat e lobe (t he papillary proc ess) ext ends bet w een t he lesser c urv e of t he st omac h and t he port al v ein and mimic s ly mphadenopat hy (8). More c audally , t he v ent ral mesoduodenum f orms t he rest of t he lesser oment um, t he hepat oduodenal ligament (153,159). T his st ruc t ure enc loses t he port al v ein, hepat ic art ery , c ommon hepat ic /c ommon bile duc t , and t he hepat ic group of c eliac ly mph nodes. T he spleen grow s in t he leav es of t he dorsal mesogast rium, just post erior t o t he st omac h. T he v ent ral part of t his P.722 mesent ery , t he gast rosplenic ligament , ult imat ely bec omes part or all of t hree v ery import ant upper abdominal st ruc t ures: t he great er oment um, t he t ransv erse mesoc olon, and t he gast rosplenic ligament (F ig. 10- 20). On sec t ions near t he spleen, t he ligament is short and is sit uat ed post eriorly ; it t ransmit s t he short gast ric v essels behind t he inf erior rec ess of t he lesser sac (F ig. 10- 21). Inf eriorly , t he perit oneum inside t he lesser sac great ly elongat es t he dorsal mesent ery . T he apposed redundant surf ac es f use t o f orm t he gast roc olic ligament , or great er oment um, w hic h c an be rec ognized by t he presenc e of t he gast roepiploic v essels, w hic h arise near t he hilus of t he spleen (F ig. 10- 22) (24). Dilat ion of t he gast roepiploic v eins is a v ery c ommon sign of splenic v ein oc c lusion, f requent ly a c onsequenc e of panc reat it is. A small post erior part of t he redundant dorsal mesent ery f uses w it h t he dorsal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1565

10 - Normal Abdominal and Pelvic Anatomy mesent ery of t he t ransv erse c olon t o c reat e t he mult i- lay ered t ransv erse mesoc olon. T he root of t his st ruc t ure lies post erior and inf erior t o t he lesser sac and c an also be ident if ied by it s v essels: t he middle c olic art ery and v ein (21) (F ig. 10- 23).

F igure 10- 18 Mesent eries at t ac hed t o t he st omac h and t he dev eloping int ramesent eric v isc era. Adapt ed f rom ref erenc e 74. A: Sc hemat ic draw ing of a sec t ion obt ained in an embry o, near t he end of t he f if t h w eek of dev elopment . T he st omac h (ST ) is support ed by t w o major mesent eries, v ent ral and dorsal. Dev eloping w it hin t he v ent ral mesent ery , and dist ort ing it s surf ac e, t he liv er (L) grow s c hief ly int o t he right perit oneal spac e (RPS). Mat ernal blood c ourses t hrough t he v ent ral part of t he v ent ral mesent ery , w hic h bec omes t he f alc if orm ligament (1). T he dorsal port ion of t his v ent ral mesent ery (2) c ont ains t he lef t gast ric art ery and c oronary v ein and, more c audally , t he hepat ic art ery , port al v ein, and biliary duc t w it hin it s leav es. T his mesent ery w ill bec ome t he lesser oment um. T he spleen (S) t akes shape in t he v ent ral part of t he dorsal mesent ery ; t he gast rosplenic ligament (3) f ormed f rom it c arries t he short gast ric v essels. Alt hough t he head of t he panc reas (P) arises in t he dorsal mesoduodenum, it s t ail grow s in a c ephalic direc t ion t o oc c upy t he dorsal mesogast rium w it hin t he splenorenal ligament (4); (A) aort a; (K) kidney ; (V) v ert ebral body ; (LPS) lef t perit oneal spac e. B: Approximat ely 1 w eek lat er, t he rapid hepat ic grow t h f orc es c onsiderable rot at ion of t he st omac h (ST ) and at t ac hed lesser oment um (2). Meanw hile, t he panc reat ic t ail (P) has f used t o t he dorsal body w all, reduc ing t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1566

10 - Normal Abdominal and Pelvic Anatomy post eromedial ext ent of t he lef t perit oneal c av it y (LPS). T his line of f usion generally c ont inues along t he splenorenal ligament t o f orm a post eromedial splenic “ bare” or nonperit onealized area. In some pat ient s, t his f usion does not oc c ur, and perit oneum ext ends behind t he post erior panc reat ic t ail. In t his c ondit ion, t he spleen is on a mesent ery of v ariable lengt h and c an “ w ander” w it hin t he perit oneal c av it y ; 1, f alc if orm ligament ; 3, gast rosplenic ligament ; 4, splenorenal ligament ; A, aort a; K, kidney ; V, v ert ebral body ; L, liv er; S, spleen.

T he dorsal segment of t he dorsal mesogast rium ext ends post eriorly f rom t he spleen t o enc lose t he panc reat ic t ail and splenic v essels, and t hen f uses w it h t he post erior body w all, joining w it h t he f asc ia ant erior t o t he lef t kidney . T his P.723 f orms t he splenorenal ligament (f ailure of t his f usion proc ess leads t o t he rare c linic al c ondit ion of “ w andering spleen” ) (3). Bec ause of t his same f usion, part of t he post eroinf erior surf ac e of t he spleen (adjac ent t o t he upper pole of t he lef t kidney ) is not perit onealized. T he splenic bare area limit s t he dist ribut ion of f luid in t he perisplenic spac e (144) (F ig. 10- 24).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1567

10 - Normal Abdominal and Pelvic Anatomy F igure 10- 19 T he gast rohepat ic and hepat oduodenal ligament s. A: T he gast rohepat ic ligament ext ends bet w een t he lesser c urv at ure of t he st omac h (ST ) and t he f issure f or t he ligamant um v enosum (bet w een ar r ow s). It c ont ains branc hes of t he lef t gast ric art ery and c oronary v eins. B: Axial sec t ion obt ained 20 mm inf erior t o (A) show s t he c ourse of t he lef t gast ric art ery (lga) t hrough t he f at - c ont aining gast rohepat ic ligament (ghl). Just ant erior t o t he c audat e lobe (CL) is a slight ly enlarged ly mph node (open ar r ow ). C : Ref ormat t ed v olume rendered image show s t he st ruc t ures of t he lesser oment um. T he low er port ion (hepat oduodenal ligament ) c ont ains t he port al v ein (pv ), c ommon hepat ic duc t (c hd) and hepat ic art ery (blac k ar r ow head). A small hepat ic c hain ly mph node is present (w hit e ar r ow head). T o t he lef t and superiorly , t he gast rohepat ic ligament (ghl) c ont ains t he lef t

gast ric art ery (lga). Not e drainage (open ar r ow ) of t he c oronary v ein int o t he port al v ein near t he splenoport al c onf luenc e. A port ion (c alled t he t uber om ent ale) of t he body of t he panc reas (p) prot rudes int o t he gast rohepat ic ligament . 2d, Desc ending duodenum; 4d, f ourt h port ion of t he duodenum; H, panc reat ic head.

T he v ent ral mesent ery of t he small int est ine and c olon dist al t o t he midduodenum resorbs and allow s f ree c ommunic at ion of t he right w it h t he lef t perit oneal spac es. T he dorsal mesent ery of t he small int est ine simply grow s t o keep pac e w it h t he rapid grow t h of t he small bow el it support s. T he dorsal mesent ery of t he c olon, how ev er, has a role t o play in f orming bot h t he upper perit oneal spac es and t he ret roperit oneal ant erior pararenal spac e (F ig. 1025). Init ially , t he c olon is a st raight t ube ly ing parallel t o t he long axis of t he f et us and supplied by t he superior mesent eric art ery v ia it s dorsal mesent ery . Wit h t ime, t he c olon elongat es and ev ent ually , w it h t he small int est ine, herniat es t hrough t he umbilic al def ec t int o t he ext raembry onic c oelomic c av it y . When t he c olon ret urns t o t he abdominal c av it y , it undergoes rot at ion (74,94). It s dist al part , w hic h w ill bec ome t he desc ending c olon in t he adult , maint ains t he same orient at ion parallel t o t he long axis of t he f et us. T he midport ion of t he c olon rot at es 90 degrees (in a c ount erc loc kw ise direc t ion, as v iew ed looking dow n on t he f et us) t o lie perpendic ular t o t he long axis. T he proximal c olon, w hic h w ill bec ome t he c ec um and asc ending port ions, undergoes y et anot her 90- degree rot at ion in t he same c ount erc loc kw ise mode, so t hat t he original lef t side of it s dorsal mesent ery now point s t o t he right side of t he abdomen. F inally , t he desc ending c olon and it s dorsal mesent ery

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1568

10 - Normal Abdominal and Pelvic Anatomy rot at e (in a c loc kw ise direc t ion, as v iew ed looking f rom f et al f oot t o f et al head), so t hat it s lef t side f uses t o t he ant erior f asc ial lining P.724 of t he lef t kidney . In a similar f ashion, t he asc ending c olon and it s mesent ery rot at e in a c ount erc loc kw ise mode, f using t o t he ant erior f asc ial lining of t he right kidney . T he t ransv erse c olon does not f use t o t he body w all; inst ead, it “ f lops” inf eriorly , so t hat t he lef t side of it s dorsal mesent ery f ac es ant eriorly . It is t his surf ac e t hat f uses t o t he post erior surf ac e of t he gast rosplenic ligament (desc ribed prev iously ) t o f orm t he t ransv erse mesoc olon. Not e t hat as a result of t hese rot at ions, t he lef t surf ac e of t he dorsal c olonic mesent ery f uses w it h t he lef t ant erior renal f asc ia, t he gast rosplenic mesent ery , and t he right ant erior renal f asc ia. T his f orms an

int erc ommunic at ing sy st em of planes t hrough w hic h pat hologic f luid c ollec t ions (not ably panc reat it is) c an be dist ribut ed t hroughout t he abdomen (2,48).

F igure 10- 20 F ormat ion of t he gast roc olic ligament . Adapt ed f rom ref erenc e 74. A: Sc hemat ic draw ing of a sagit t al sec t ion t hrough a dev eloping embry o. Grow t h of t he right perit oneal spac e (RPS) behind t he st omac h (ST ) has great ly elongat ed t he gast rosplenic ligament (GSL), so t hat it hangs like a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1569

10 - Normal Abdominal and Pelvic Anatomy

drape ov er t he t ransv erse c olon (T C) and it s at t ac hed dorsal mesent ery (dm); P, panc reas; d, duodenum; J, jejunum. B: F usion oc c urs bet w een ant erior and post erior surf ac es of t he gast rosplenic ligament , oblit erat ing part of t he right perit oneal spac e (RPS) and f orming t he gast roc olic ligament (gc l). T he post erior surf ac e of t he f used ligament in t urn f uses t o t he t ransv erse c olon (T C) and it s dorsal mesent ery t o f orm t he adult t ransv erse mesoc olon (t mc ); P, panc reas; d, duodenum; J, jejunum; ST , st omac h.

Peritoneal Spaces Complex rot at ion and f usion of mesent eric st ruc t ures alt er t he perit oneal anat omy ; grow t h of int ramesent eric organs, espec ially t he liv er, f urt her dist ort s it s appearanc e. A sc hemat ic ov erv iew of t he dist ribut ion of perit oneal spac es in t he adult is show n in F ig. 10- 26. T he lef t per it oneal spac e in t he adult c an be div ided int o f our c ompart ment s (all of w hic h int erc ommunic at e): t w o perihepat ic spac es, ant erior and post erior; and t w o subphrenic spac es, ant erior and post erior (F ig. 10- 27). T he lef t ant erior perihepat ic spac e is c onf ined on t he right by t he f alc if orm ligament . T he lef t post erior perihepat ic spac e f ollow s t he undersurf ac e of t he lat eral segment of t he lef t hepat ic lobe, and ext ends deep int o t he f issure f or t he ligament um v enosum (7,91,122,147). T he lef t ant erior subphrenic spac e is t he c ont inuat ion of t he ant erior perihepat ic spac e (53). It c ourses ov er t he gast ric f undus just post erior t o t he ant erior leaf of t he lef t hemidiaphragm. Large c ollec t ions in t he lef t perit oneal spac e c an ext end superiorly t hrough t he diaphragmat ic hiat us int o t he mediast inum (45), or post erolat erally int o t he post erior subphrenic (perisplenic ) spac e. T his spac e c ov ers t he superior and inf erolat eral surf ac es of t he spleen, P.725 but is c onf ined medially by t he splenorenal ligament and t he bare area of t he spleen. Below t he spleen, t he phrenic oc olic ligament separat es t he perisplenic spac e f rom t he rest of t he perit oneal c av it y (F ig. 10- 28). T he r ight per it oneal spac e has t w o major div isions: t he perihepat ic spac e and t he lesser sac (oment al bursa). T he right perihepat ic spac e oc c upies t he broad expanse bet w een t he ant erior and lat eral surf ac es of t he right lobe of t he liv er and t he right hemidiaphragm. It is c onf ined on t he lef t and ant eriorly by t he f alc if orm ligament , and post eriorly by t he right c oronary ligament , w hic h marks t he lat eral aspec t of t he bare area of t he liv er (120) (F ig. 1029). On suc c essiv ely c audal sc ans, t he lat erally plac ed perit oneal rec ess

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1570

10 - Normal Abdominal and Pelvic Anatomy ext ends more and more medial as t he bare area bec omes smaller; at t he lev el

of t he upper right renal pole, it t urns ant erior t o oc c upy a spac e bet w een t he post erior liv er surf ac e and t he ant erior renal f asc ia (121). T his post erior rec ess is named t he hepat or enal f ossa or t he Mor ison pouc h. On sc ans below t he gallbladder f ossa, t he perihepat ic spac e c omplet ely enc irc les t he right hepat ic segment s (F ig. 10- 30). T he anat omy of t he lesser sac at t est s t o it s c omplex embry ologic origin. As desc ribed prev iously , it is a part of t he right perit oneal spac e t hat is displac ed as t he liv er grow s t o f ill t he right upper abdomen. T he right perit oneal spac e t hen mov es medially behind t he gast rohepat ic ligament and st omac h and is enf olded by t he redundant gast ro- splenic ligament . As a result , c ollec t ions in t he lesser sac are dif f ic ult t o ac c ess by perc ut aneous punc t ure; t hat spac e is c omplet ely surrounded by mesent eries and int ramesent eric organs (96). In t he adult , t w o major rec esses are present . T he superior rec ess c omplet ely enc loses t he medial surf ac e of t he c audat e lobe (117) (F ig. 10- 31). At t he port a hepat is, t he superior rec ess lies just post erior t o t he port al v ein; on more c ephalic sec t ions, it lies immediat ely behind t he lesser oment um deep w it hin t he f issure f or t he ligament um v enosum P.726 P.727 and f ollow s t he c audat e lobe surf ac e post eriorly and t o t he right , ext ending almost t o t he inf erior v ena c av a. Near t he diaphragm, t he post erior part of t his spac e lies adjac ent t o t he right diaphragmat ic c rus, just inf erior t o t he abdominal segment of t he esophagus (4). T he inf erior rec ess of t he lesser sac (see F ig. 10- 29) lies bet w een t he st omac h and t he v isc eral surf ac e of t he spleen; on low er sec t ions, it separat es t he st omac h f rom t he panc reas and t he t ransv erse mesoc olon (30,66). Part of t his spac e may pot ent ially ext end bet w een t he leav es of t he great er oment um (F ig. 10- 32).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1571

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 21 T he gast rosplenic ligament . A: Comput ed t omography sec t ion t hrough t he upper abdomen in a pat ent w it h asc it es show s f luid- f illed perit oneal spac es out lining t he gast rosplenic ligament (gsl). T he gast rosplenic ligament is t he f at - c ont aining st ruc t ure bet w een t he lef t ant erior subphrenic spac e (LAS) and t he inf erior rec ess of t he lesser sac (ls). T he serpent ine st ruc t ures w it hin t his f at are t he short gast ric art eries, w hic h arise f rom t he splenic art ery and supply t he great er c urv at ure of t he st omac h (ST ). Embry ologic ally , t he gast rosplenic ligament f orms part of t he t ransv erse mesoc olon and all of t he great er oment um. S, spleen. B: F luid in t he gast rosplenic ligament . In t his pat ient w it h panc reat it is, a large f luid c ollec t ion (F ) w it hin t he gast rosplenic ligament dist ort s t he post erolat eral w all of t he st omac h (ST ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1572

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 22 T he great er oment um. A: Axial sec t ion in a pat ient w it h w idespread perit oneal met ast ases show s ext ensiv e sof t t issue inv olv ement of t he great er oment um (GO). Oment al f at (ar r ow ) and gast roepiploic v essels (ar r ow head) persist . B: Sagit t al image in t he same pat ient demonst rat es t he c ephaloc audal ext ent of t he oment um (GO) and t he gast roepiploic v essels (ar r ow head) c oursing w it hin t he small amount of preserv ed oment al f at .

Posterior Recesses of the Peritoneum T he prec ise dist ribut ion of t he most post erior rec esses of t he perit oneal spac es depends on t he c omplet eness of f usion bet w een t he dorsal mesent eries and t he post erior abdominal ret roperit oneum. When f usion is inc omplet e, perit oneum may ext end post erior t o t he renal margin on eit her side. Bec ause mobile st ruc t ures in t he perit oneal c av it y c an inhabit any port ion of t he perit oneal spac e, it is possible f or t he c olon or spleen t o lie in a ret rorenal or ret rogast ric posit ion (59,105). Clearly , t his v ariat ion may be a c onsiderable hazard t o pat ient s undergoing perc ut aneous renal proc edures.

Extraperitoneal Organs, Spaces, and Planes

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1573

10 - Normal Abdominal and Pelvic Anatomy

T he ext raperit oneal spac es inc lude all st ruc t ures t hat lie bet w een t he ext ernal part of t he t ransv ersalis f asc ia and t he perit oneal lining. T here are t w o major c omponent s t o t he ext raperit oneal spac es: t he abdominal ret roperit oneum, and t he pelv ic periv esic al spac e. T he lat t er w ill be c onsidered in t he port ion of t his c hapt er t hat deals w it h pelv ic anat omy . T here is really no c onsist ent def init ion of t he region ref erred t o as t he abdom inal r et r oper it oneum . T he most c ommonly ac c ept ed def init ion ref ers t o t he ret roperit oneum as t he f at - f illed c ompart ment t hat lies bet w een t he pariet al perit oneum and t he t ransv ersalis f asc ia. How ev er, imaging observ at ions suggest t hat t he ret roperit oneum is not a t ot ally separat e c ompart ment , but is c ont inuous w it h port ions of t he ant erior abdominal w all, w it h t he pelv ic periv esic al ext raperit oneal spac e (27,43), and w it h t he mesent eries disc ussed in t he sec t ion on perit oneum. T he purpose of t his sec t ion is t o inc orporat e t hese c linic al observ at ions of t he dist ribut ion of ret roperit oneal f luid w it h t he c lassic ally desc ribed anat omy . Rapidly ev olv ing f luid c ollec t ions (f or example, t hose seen in sev ere panc reat it is) are t oo large t o be maint ained in t heir spac e of origin (29,89). Surprisingly , ev en aggressiv e proc esses t ake v ery w ell- def ined rout es t o esc ape: t hey eit her dissec t int o an adjac ent mesent ery (a proc ess know n as subper it oneal spr ead) (106,123) or t hey ev ac uat e int o f asc ial planes t hat lie bet w een t he ret roperit oneal spac es (int r af asc ial spr ead). It is t he lat t er t hat explains t he c onnec t ions observ ed bet w een t he diaphragm superiorly and t he ext rav esic al pelv ic spac es inf eriorly (2,15,48,69,93,103,142,158).

Great Vessel Space T he aort a and it s major v isc eral branc hes as w ell as t he inf erior v ena c av a and it s t ribut aries c ourse w it hin an ill- def ined spac e ant erior t o t he v ert ebral bodies (F ig. 10- 33). T his spac e is a c audal c ont inuat ion of t he post erior mediast inum, but no disc ret e f asc ial planes c onf ine it , and proc esses may ext end f rom it t o inv olv e ot her ret roperit oneal spac es. Paraaort ic and parac av al ly mph nodes ac c ompany t he ent ire c ourse of P.728 P.729 P.730 t he abdominal aort a and v ena c av a. T he diaphragmat ic c rura enc lose t he upper part of t he abdominal aort a, ending in a f ibrous arc h, t he median arc uat e ligament , immediat ely c ephalic t o t he lev el of t he c eliac t runk. T he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1574

10 - Normal Abdominal and Pelvic Anatomy

origin of t he superior mesent eric art ery is 1 t o 2 c m c audal; t he c ourse of t his art ery parallels t he aort a ov er sev eral c ent imet ers. Approximat ely 1 t o 2 c m more c audal, t he renal art eries exit t he aort a lat erally or post erolat erally t o ent er t he renal hila. T he right renal art ery passes behind t he inf erior v ena c av a (IVC) in it s c ourse. Abov e t he aort ic bif urc at ion 1 t o 2 c m, t he inf erior mesent eric art ery exit s t he lef t ant erolat eral surf ac e of t he aort a and giv es of f lef t c olic , sigmoid, and superior rec t al branc hes.

F igure 10- 23 T he t ransv erse mesoc olon. A: Volumet ric axial ref ormat t ed image t hrough t he midabdomen show s t he middle c olic art ery (mc a) arising f rom t he superior mesent eric art ery (sma) and branc hing w it hin t he t ransv erse mesoc olon t o supply t he t ransv erse c olon (T C). T ribut aries of t he middle c olic v ein (ar r ow s) here drain direc t ly int o t he superior mesent eric v ein (smv ). P, panc reat ic head and unc inat e proc ess. B: Coronal ref ormat t ed image in t he same pat ient show s t he t ransv erse mesoc olon spanning t he ent ire upper abdomen. T he middle c olic v eins (ar r ow s) mark t he posit ion of t he mesoc olon, w hic h lies immediat ely superior t o t he panc reas (P) and inf erior t o t he st omac h (ST ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1575

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 24 T he bare area of t he spleen. A: T he lef t post erior subphrenic (perisplenic ) spac e (LPS) nearly enc irc les t he spleen (SP). A port ion (ar r ow s) of it s post erior surf ac e, adjac ent t o t he lef t kidney (LK) is non- perit onealized; it is part of t he splenorenal ligament , w hic h f used t o bec ome part of t he ret roperit oneum. B: In t his pat ient , ret roperit oneal gas (ast er isk) f rom a duodenal perf orat ion out lines t he bare area of t he spleen (SP). LK, lef t kidney ; lad, lef t adrenal gland.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1576

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 25 Embry ologic grow t h and rot at ion of t he c olon. A: Line draw ing of t he f et al abdominal c av it y prior t o c olonic rot at ion. T he c olon begins as a relat iv ely st raight t ube support ed by t he dorsal mesent ery (DM). At t his point in embry ologic dev elopment , t he post erior body surf ac e is c omprised of t he ant erior surf ac es of t he kidney s and t he perirenal f at t hat surrounds t hem. LK,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1577

10 - Normal Abdominal and Pelvic Anatomy lef t kidney ; RK, right kidney ; P, panc reas; DC, desc ending c olon; AC, asc ending c olon. B: Af t er c onsiderable elongat ion, t he c olon rot at es so t hat t he asc ending c olon (AC) undergoes a 180- degree rot at ion and t hen “ f lops” t o t he right on it s dorsal mesent ery . In t his w ay , t he original lef t surf ac e of t hat mesent ery f uses w it h t he ant erior port ion of t he right perirenal spac e in f ront of t he right kidney (RK). In similar f ashion, t he

desc ending c olon (DC) and it s dorsal mesent ery sw ings t o t he lef t , so t hat it s lef t surf ac e f uses in f ront of t he lef t kidney (LK) and perirenal spac e. T hese f usions produc e sy mmet ric ret romesent eric planes inf erior t o t he t ransv erse c olon (T C). T he dorsal mesent ery (DM) of t he t ransv erse c olon does not f use post eriorly ; it s lef t surf ac e f ac es ant eriorly . P, panc reas; SC, sigmoid c olon. C : T he elongat ed gast rosplenic ligament hangs like a drape in t he f ront of t he abdominal c av it y , w here it f orms t he great er oment um (go). It s post erior surf ac e f uses w it h t he dorsal mesent ery of t he t ransv erse c olon (T C) t o f orm t he t ransv erse mesoc olon (T MC). ST , st omac h; P, panc reas.

F igure 10- 26 Perit oneal spac es of t he upper abdomen. On t hese sc hemat ic draw ings, t he lef t perit oneal spac es are draw n w it h heav y blac k lines, and t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1578

10 - Normal Abdominal and Pelvic Anatomy right perit oneal spac es hav e v ert ic al hat c hing. A: Near t he gast roesophageal junc t ion, f our div isions of t he lef t perit oneal spac e are present . Ant erior t o t he liv er, medially limit ed by t he f alc if orm ligament (c ur v ed ar r ow ) is t he lef t

ant erior perihepat ic spac e (1). Curv ing post erior t o c ov er t he v isc eral hepat ic surf ac e is t he lef t post erior perihepat ic spac e (2). T he ant erior subphrenic spac e (3) separat es t he gast ric f undus (ST ) f rom t he diaphragm, and t he post erior subphrenic spac e (4) (also c alled t he per splenic spac e) surrounds t he spleen. T he right perit oneal spac e c onsist s of t w o perihepat ic spac es and t w o port ions of t he lesser sac . T he perihepat ic spac es c onsist of a broad diaphragmat ic surf ac e (5), limit ed on t he lef t by t he f alc if orm ligament (c ur v ed ar r ow ) and post eromedially by t he bare area (st r aight ar r ow marks t he perit oneal ref lec t ion). T he sec ond part of t he right perihepat ic spac e, t he hepat orenal f ossa, is present on more c audal sec t ions. T he lesser sac c onsist s of a superior rec ess (6) surrounding t he c audat e lobe (CL) and an inf erior rec ess (7) t hat lies post erior t o t he st omac h. T he t w o are anat omic ally c ont inuous st ruc t ures, but t he gast rohepat ic f old is int erposed bet w een t hem on c ephalic sec t ions; L, liv er; e, esophagus; V, v ert ebral body . B: T w o c m c audal, t he superior rec ess of t he lesser sac (6) surrounds t he c audat e lobe on t hree sides. T he perit oneal ref lec t ion at t he hepat ic bare area (st r aight ar r ow ) is more post erior and medial t han on t he prev ious sec t ion; (c ur v ed ar r ow ) f alc if orm ligament ; (ST ) st omac h; (S) spleen; (P) panc reas; (LK) lef t kidney ; (V) v ert ebral body ; (L) liv er. C : T w o c m c audal, t he post erior subphrenic (perisplenic ) spac e is limit ed inf eriorly by t he phrenic oc olic ligament (ar r ow head) f ormed w hen t he proximal desc ending c olon (DC) and it s at t ac hed dorsal mesent ery f uses t o t he post erior body w all and t o t he lat eral margin of t he diaphragm. At t his lev el, t he post erior lef t perihepat ic spac e (2) ext ends deep int o t he v isc eral surf ac e of t he liv er, near t he lef t port al v ein (LPV). T he superior rec ess of t he lesser sac surrounds t he papillary proc ess (pp) and c audat e proc ess (c p), w hic h t oget her c omprise t he c audat e lobe of t he liv er. T he c ephalic port ion of t he v isc eral right perihepat ic perit oneum (8) is limit ed lat erally by t he t riangular ligament (st r aight ar r ow ); L, liv er; c ur v ed ar r ow , f alc if orm ligament ; ST , st omac h; DJ, duodenojejunal f lexure; P, panc reas; RK, right kidney ; LK, lef t kidney ; V, v ert ebral body . D: F our c m c audal, t he lef t post erior perihepat ic spac e (2) c ont ac t s t he ant erior w all of t he gallbladder (gb). T he inf erior rec ess of t he lesser sac (7) ext ends int o t he leav es of t he great er oment um (GO), w hic h lies ant erior t o t he dist al t ransv erse c olon (T C). T he v isc eral right perihepat ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1579

10 - Normal Abdominal and Pelvic Anatomy spac e (also know n as t he hepat or enal spac e or t he Mor ison pouc h) ext ends bet w een t he v isc eral surf ac e of t he liv er and t he right kidney (RK); it is

c ont inuous, by w ay of t he f oramen of Winslow , w it h t he superior rec ess of t he lesser sac ; L, liv er; c ur v ed ar r ow f alc if orm ligament ; LK, lef t kidney ; V, v ert ebral body ; J, jejunum; ST , st omac h; d, duodenum; DC, desc ending c olon.

F igure 10- 27 Lef t perit oneal spac es. A: Axial sec t ion t hrough t he upper abdomen in t his pat ient w it h dif f use asc it es show s f luid in t he lef t ant erior subphrenic (LAS) spac e, produc ing post erior displac ement of t he st omac h (ST ) and great er oment um (GO) f rom t he lef t hemidiaphragm. T here is a small amount of f luid in t he lef t ant erior perihepat ic spac e (LAP), c irc umsc ribed on t he right by t he f alc if orm ligament (ar r ow ). B: Axial sec t ion 3 c m inf erior t o (A) show s post erior ext ension of t he lef t post erior perihepat ic spac e (LPP), ly ing bet w een t he st omac h (ST ) and t he lat eral segment of t he lef t hepat ic lobe (L). T he perisplenic spac e (LPS) is separat ed f rom t he f luid in t he inf erior rec ess of t he lesser sac (LS) by t he t ransv erse mesoc olon (T MC). C : Axial sec t ion 2 c m inf erior t o (B) show s t he lef t post erior perihepat ic spac e (LPP)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1580

10 - Normal Abdominal and Pelvic Anatomy

separat ed f rom t he inf erior rec ess of t he lesser sac (LS) by t he gast rohepat ic ligament (ghl). T he t ransv erse mesoc olon (T MC) f orms t he lat eral w all of t he lesser sac , separat ing it f rom t he lef t post erior subphrenic spac e (LPS) around t he spleen.

T he IVC passes t hrough it s hiat us w it hin t he c ent ral t endon of t he diaphragm. Just c audal t o t his lev el, it rec eiv es t he t hree major hepat ic v eins, w hic h serv e t o mark t he boundaries of t he f our major liv er segment s. Inf eriorly , it is sit uat ed on a groov e on t he post erior surf ac e of t he c audat e lobe; f at is rarely seen int erposed bet w een t he t w o. At it s low er int rahepat ic margin, t he IVC is immediat ely ant erior t o t he right adrenal gland; a f at plane separat es it f rom t he right diaphragmat ic c rus. It is in t his spac e t hat t he right port ion of t he c eliac ganglion ramif ies. Just inf erior t o it s hepat ic c ourse, t he IVC is c lose t o t he port al v ein; t he f at (and nodal c ont ent s) bet w een t hem has been t ermed t he por t ac av al spac e (159). T his spac e c ont ains t he hepat ic group of ly mph nodes, ly ing w it hin t he hepat oduodenal ligament . More c audally , t he unc inat e proc ess of t he panc reas is int erposed bet w een t he superior mesent eric v ein and t he IVC. Bot h t he IVC and t he aort a are c rossed ant eriorly by t he t ransv erse port ion of t he duodenum. Caudal t o t his, t he IVC is relat ed predominant ly t o t he root of t he small int est inal mesent ery . T he IVC div ides approximat ely 1 t o 2 c m c audal t o t he aort a bif urc at ion. T he lef t c ommon iliac v ein t hen passes post erior t o t he right c ommon iliac art ery bef ore P.731 arriv ing at a point post erior and slight ly medial t o t he lef t c ommon iliac art ery .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1581

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 28 T he phrenic oc olic ligament . Coronal ref ormat t ed image f rom t he pat ient illust rat ed in F ig. 10- 27 show s t he c ont inuit y of t he lef t post erior perihepat ic spac e (LPP) w it h t he lef t ant erior subphrenic spac e (LAS) and lef t post erior subphrenic spac e (LPS). T he t ransv erse mesoc olon (T MC) separat es t he perisplenic spac e f rom t he inf erior rec ess of t he lesser sac (LS) behind t he st omac h (ST ). Just inf erior t o t he spleen (SP), t he lat eral ext ension of t he t ransv erse mesoc olon, c alled t he phr enic oc olic ligam ent (PCL), at t ac hes t o t he lef t hemidiaphragm (ar r ow ).

Immediat ely post erior t o t he IVC and post erolat eral t o t he aort a, on t he ant erolat eral surf ac e of t he v ert ebral bodies, lie t he sy mpat het ic t runks. T hree major t runks of ly mphat ic s also c ourse w it hin t his spac e, one on eac h side of t he great v essels, and one bet w een t hem. T he proximal port ion of t he uret ers pass just lat eral t o t he great v essel spac e; primary proc esses around t he v essels of t en af f ec t t he uret ers also. Examples inc lude ret roperit oneal f ibrosis and perianeury smal f ibrosis (F ig. 10- 34). A port ion of t he asc ending lumbar v ein passes along t he lat eral surf ac e of t he v ert ebral body draining int o t he azy gos/hemiazy gos sy st em. T hese v eins are rec ruit ed as c ollat eral pat hw ay s w hen t he IVC is obst ruc t ed and are v isible as c ont rast - f illed st ruc t ures w it hin t he great v essel spac e (108). F luid c ollec t ions originat ing w it hin t he spac e around t he great v essels c an c ommunic at e w it h t he ret roperit oneum v ia a number of pat hw ay s. T he most c ommon example is aort ic hemorrhage. Many aneury sms bleed post eriorly and c an bec ome c onf ined t o t he psoas spac e (67) or ext end int o t he f asc ial plane behind t he lef t kidney (F ig. 10- 35). Very of t en, hemorrhage is present w it hin one or bot h perirenal spac es as w ell (119,128). T he f asc ial planes ant erior t o t he kidney s are less c ommonly inv olv ed but are ac c essible also f rom t he great v essel spac e (42).

Psoas Spaces T he psoas and quadrat us lumborum musc les lie post erior t o t he t ransv ersalis f asc ia, w hic h plac es t hem post erior t o t he c lassic al limit s of t he ret roperit oneum. T hey are c onsidered here, how ev er, bec ause of t he f requenc y w it h w hic h pat hologic proc esses beginning in t he c lassic al ret roperit oneum ext end int o t he psoas c ompart ment . T he f asc ia around t he psoas musc les f orm a py ramidal spac e t hat pot ent ially c onnec t s t he mediast inum w it h t he low er ext remit y . T he psoas musc le begins at t he v ert ebral body and int erv ert ebral spac e of t horac ic v ert ebra T 12 t o L1,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1582

10 - Normal Abdominal and Pelvic Anatomy and passes post erior t o t he c rura of t he diaphragm under t he medial arc uat e ligament . It s ant erior and lat eral borders are ensheat hed w it h f asc ia. T he post erior renal f asc ia c ov ering t he hilus and low er pole of t he kidney s insert s P.732 on t he psoas f asc ia, est ablishing a pot ent ial c ommunic at ion bet w een t he perirenal and psoas spac es. Abov e t he renal hilus, t he post erior renal f asc ia insert s lat eral t o t he psoas, so t hat t he t w o spac es t end t o be separat e at t his lev el and higher (38).

F igure 10- 29 Right perit oneal spac es. Oblique c oronal ref ormat t ed image show s a large f luid c ollec t ion in t he right subphrenic spac e (RS), w hic h is limit ed superiorly by t he f alc if orm ligament (ar r ow ). T his c ont inues post eroinf eriorly w it h t he hepat orenal spac e (HRS), also know n as t he Mor ison pouc h. T hat , in t urn, c ommunic at es t hrough t he f oramen of Winslow w it h t he superior rec ess of t he lesser sac (SR) adjac ent t o t he c audat e lobe (CL) of t he liv er. F rom t here, it ext ends post eroinf eriorly int o t he inf erior rec ess of t he lesser sac (IR) inf erior t o t he st omac h (ST ). At t his lev el, t he gast rohepat ic ligament (ghl) prot rudes int o t he lesser sac .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1583

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 30 T he Morison pouc h and t he bare area. Right perit oneal spac e c ollec t ions. Pat ient w it h int raperit oneal rupt ure of t he urinary bladder, w ho underw ent c omput ed t omography c y st ography ; dilut e iodinat ed c ont rast mat erial has f illed t he right perit oneal spac es. A: Sec t ion t hrough t he inf erior port ion of t he port a hepat is. Dilut e c ont rast f ills t he right perihepat ic spac e (rp), separat ed on t his sec t ion f rom t he hepat orenal f ossa (hr) by t he c audal margin of t he bare area of t he liv er (ar r ow ). Some of t he c ont rast in t he hepat orenal f ossa has ext ended ant eriorly t o surround t he c audat e lobe of t he liv er (L), out lining t he superior rec ess of t he lesser sac (sr). Not e t he posit ion of t his c ont rast bet w een t he port al v ein (PV) and t he inf erior v ena c av a (C). At t his lev el, t he lef t gast ric f old at t he root of t he gast rohepat ic ligament

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1584

10 - Normal Abdominal and Pelvic Anatomy (gh) separat es t he superior rec ess f rom t he inf erior rec ess (ir), w hic h lies

behind t he f luid- f illed st omac h (ST ). B: Sec t ion obt ained 8 mm c audal t o (A). Communic at ion bet w een t he hepat orenal f ossa (hr) and t he superior rec ess of t he lesser sac (sr) by w ay of t he f oramen of Winslow (f W) is c learly depic t ed on t his sec t ion. A, aort a; ST , st omac h; D, duodenum; PV, port al v ein; ir, inf erior rec ess of t he lesser sac . C : Axial magnet ic resonanc e image in anot her pat ient w it h asc it es. T he t riangular ligament (ar r ow ) is out lined by hy perint ense asc it ic f luid in t he right perihepat ic (subphrenic ) spac e (ph) and in t he hepat orenal f ossa (hr), or t he Morison pouc h. RK, right kidney ; L, liv er.

On t he medial surf ac e of t he psoas musc les, t here are t endinous arc hes c oursing ov er t he c onst ric t ed middle port ion of t he v ert ebral bodies. Medial t o t hese arc hes are t he lumbar v eins, lumbar art eries and sy mpat het ic t runks (143) (F ig. 10- 36). Post erolat erally , t he psoas musc les c ov er t he int erv ert ebral f oramina, so t hat lumbar nerv es, w hic h c ont ribut e t o t he lumbosac ral plexus, c ourse c audally w it hin t he subst anc e of t he musc le (44). T hese nerv es t hen pass ant erolat erally t o f orm named peripheral nerv es: t he genit of emoral nerv e lies on t he ant erior surf ac e of t he psoas musc le near t he uret er; t he lat eral f emoral c ut aneous nerv e P.733 lies on it s post erolat eral surf ac e (w it hin t he post erior pararenal spac e); t he f emoral nerv e passes behind t he psoas musc le in a groov e bet w een it and t he iliac musc le; and t he obt urat or nerv e remains on t he post eromedial surf ac e of t he psoas, post erolat eral t o t he iliac art eries and v eins. T hus, proc esses arising in t he psoas spac e c an produc e sy mpt oms in ev ery low er limb dist ribut ion. In pat ient s w it h plexif orm neurof ibromat osis, enlargement of t hese nerv es produc es st riking def ormit y of t he psoas musc le (13) (F ig. 10- 37).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1585

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 31 Superior rec ess of t he lesser sac . Perit oneal f luid c ollec t ions. Pat ient rec ov ering f rom biliary surgery c omplic at ed by bile leakage. Sec t ion t hrough t he liv er (L) just abov e t he port a hepat is show s a large perit oneal f luid c ollec t ion (LP) in t he lef t post erior perihepat ic spac e. It is separat ed f rom a smaller c ollec t ion (SR) in t he superior rec ess of t he lesser sac by t he gast rohepat ic ligament . A, aort a; ST , st omac h; S, spleen.

T he medial port ion of t he psoas spac e also c ont ains ly mphat ic s, and it is t his spac e t hat enlarges in pat ient s w it h neoplast ic or inf lammat ory ly mph node disease, displac ing t he psoas f ibers lat erally and ant eriorly .

Kidneys and Perirenal Spaces T he kidney and it s assoc iat ed suprarenal gland are enc losed in an env elope of perirenal f at , w hic h in t urn is sheat hed w it hin t he renal f asc ia (22,80,116). On CT sec t ions, t he post erior renal f asc ia is w ell def ined and smoot hly c ont inuous w it h t he lat eroc onal f asc ia, w hic h ext ends ant eriorly just lat eral t o t he asc ending or desc ending c olon. T he t hinner, less w ell- def ined ant erior renal f asc ia int ersec t s t he post erior renal f asc ia at an ac ut e angle (F ig. 10- 38). Bot h t he ant erior and post erior renal f asc iae are laminar (115), and f luid c ollec t ions c an dissec t bet w een t heir leav es t o ext end lat erally t o simulat e inv olv ement of t he post erior pararenal spac e (F ig. 10- 39). T he pot ent ial spac e ant erior t o t he kidney is f ormed w hen t he dorsal mesent ery of t he c olon rot at es and f uses t o t he ant erior renal f asc ia during

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1586

10 - Normal Abdominal and Pelvic Anatomy embry ologic dev elopment (as disc ussed prev iously ). T his line of f usion c ont inues lat erally t o f orm t he lat eroc onal f asc ia on bot h sides. F luid c ollec t ions f rom a v ariet y of sourc es ut ilize t hese f asc ial planes t o c ommunic at e t o ot her part s of t he ret roperit oneum. P.734 P.735

Bec ause t his f usion plane is c ont inuous w it h t he plane f ormed post erior t o t he panc reas and duodenum af t er t hey f orm part of t he ant erior pararenal spac e, ret roperit oneal f luid c ollec t ions use t his pat hw ay t o c ross f rom one side t o t he ot her. T he observ at ion t hat f luid c ollec t ions in t he ret roperit oneum c an c ross t he midline has been c onf irmed in c adav er experiment s (71,92,133) (F ig. 1040).

F igure 10- 32 Ext ension of f luid bet w een leav es of great er oment um. A: Axial sec t ion in a pat ient w it h gast ric perf orat ion int o lef t perit oneal spac e and t he lesser sac . Air and c ont rast is present in t he lef t ant erior (LAP) and lef t post erior (LPP) perihepat ic spac es. Anot her denser c ollec t ion is separat ed f rom t hose spac es and f rom t he lef t hemidiaphragm (ar r ow ) by a f at t y band c ont aining gast roepiploic v essels (ar r ow heads). B: Axial sec t ion 2 c m inf erior t o (A) show s air and c ont rast in t he inf erior rec ess of t he lesser sac (IR), w hic h ext ends (c ur v ed ar r ow ) bet w een t he leav es of t he great er oment um (c ur v ed ar r ow ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1587

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 33 Great v essel spac e. A: Axial sec t ion show s t he c ont ent s of t he upper port ion of t he great v essel spac e, w hic h lies bet w een t he t w o perinephric spac es. On t he right , t he inf erior v ena c av a (IVC) marks t he post erior boundary of t he spac e; just medial t o it , w it hin t he periv asc ular f at , is t he inf erior phrenic art ery (ar r ow head) and t he c eliac neural plexus (not v isible, but reliably present at t his lev el). B: Coronal sec t ion t hrough t he post erior aspec t of t he great v essel spac e show s t he renal art eries (ar r ow s) ext ending int o t he perirenal f at t o supply t he kidney s. T his prov ides c ont inuit y bet w een t he great v essel spac e and t he perirenal f at . * , F at in great v essel spac e. C : Coronal sec t ion 2 c m ant erior t o (B) show s t he c ourse of t he lef t renal v ein (lrv ), rec eiv ing t ribut aries f rom t he gonadal v ein (gv ) and lef t adrenal v ein (lav ) as it c rosses ant erior t o t he aort a t o drain int o t he inf erior v ena c av a (IVC). T he short er right renal v ein (rrv ) has a more v ert ic al c ourse and does not t y pic ally rec eiv e a gonadal t ribut ary . D: Oblique v olumet ric perspec t iv e rendering show s t he aort a and it s major branc hes: t he c eliac t runk (c t ), superior mesent eric art ery (sma), renal art eries (ar r ow s) and t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1588

10 - Normal Abdominal and Pelvic Anatomy inf erior mesent eric art ery (ima). A port ion of t he lef t renal v ein (lrv ) is seen c rossing ant erior t o t he aort a.

F igure 10- 34 Early ret roperit oneal f ibrosis af f ec t ing c ont ent s of t he great v essel spac e. A: Axial MR inf erior t o t he renal hila show s high- int ensit y inf lammat ory t issue surrounding t he aort a (A), and ext ending behind t he inf erior v ena c av a (IVC), but not inv olv ing eit her perinephric spac e. B: Sec t ion obt ained 2 c m inf erior t o (A) show s t he proc ess t o be c onf ined t o t he spac e surrounding t he aort a (A) and inf erior v ena c av a (IVC). It is limit ed ant eriorly by t he root of t he int est inal mesent ery (rm) and post eriorly by t he v ert ebral body (V) and psoas musc les. Lat erally , it ext ends t o t he medial boundary of t he uret ers (U). C : Sec t ion obt ained just abov e t he aort ic bif urc at ion show s t he inf erior ext ent of t his proc ess, w hic h surrounds bot h great v essels and ext ends lat erally t o t he medial boundary of t he uret ers (U). D: Coronal sec t ion t hrough t he upper abdomen show s t he c ephaloc audal ext ent of t his inf lammat ory proc ess w it hin t he great v essel spac e.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1589

10 - Normal Abdominal and Pelvic Anatomy T he perirenal spac e c ont ains t he kidney s, adrenal glands, renal hilar v essels, renal pelv is and proximal uret er, and a v ariable quant it y of f at . T hese c ont ent s are enc losed P.736 bet w een t he renal f asc ial lay ers; medially , t he perirenal spac es c ommunic at e by w ay of t he hilar v essels w it h t he great v essel spac e. T he largest f at ac c umulat ion in t he perinephric spac e is medial t o t he low er pole; absc esses,

hemat omas, and urinomas hav e a t endenc y t o ac c umulat e in t his loc at ion. T he f at in t he perirenal spac e c ont ains numerous sept at ions t hat may loc ally c onf ine perinephric f luid c ollec t ions (68,73,129). T he sept at ions also aid in rout ing rapidly ac c umulat ing f luid out of t he perirenal spac e int o t he surrounding f asc ial planes (79,129) (F ig. 10- 41). Moreov er, f luid c ollec t ions under pressure (part ic ularly f rom panc reat it is) c an t rac k int o t he perirenal spac e t hrough t hese same sept at ions, t o mimic subc apsular renal c ollec t ions (37,102) (F ig. 10- 42).

F igure 10- 35 Ext ension of aort ic rupt ure. Ret rorenal plane. Sec t ion just inf erior t o t he hila of t he kidney s, in a pat ient w ho has undergone prev ious aort ic graf t surgery , show s a large aort ic aneury sm (A), f rom w hic h blood has leaked int o a w ell- demarc at ed plane ly ing bet w een t he post erior pararenal f at (pp) and t he perirenal f at (pr). T he v olume of t his c ollec t ion (rr) has produc ed displac ement of t he lef t kidney (LK) as w ell as st ruc t ures w it hin t he ant erior

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1590

10 - Normal Abdominal and Pelvic Anatomy pararenal spac e: t he panc reat ic t ail (P) and t he spleen (S). T his ret rorenal plane is c ont inuous w it h t he inf erior diaphragmat ic f asc ia.

T he adrenal glands lie superior and medial t o eac h kidney ; t he right adrenal is relat ed t o t he post erior surf ac e of t he IVC, and it s lat eral limb may be so c losely apposed t o t he liv er t hat it is indisc ernible. T he medial limb lies c lose t o t he right diaphragmat ic c rus; bet w een it and t he c rus lies t he c eliac ganglion. T he lef t adrenal is c losely relat ed t o t he t ail of t he panc reas and it s v essels, t he splenic art ery and v ein. It also present s a medial surf ac e c lose t o t he lef t diaphragmat ic c rus. Congenit al gast ric div ert ic ula or dilat ed peripanc reat ic v essels oc c ur in t he region of t he lef t adrenal and may mimic adrenal pat hology (F ig. 10- 43). T he uret er oc c upies t he perirenal spac e c audal t o t he renal hilus. At t he lev el of t he low er pole, it passes int o t he spac e surrounding t he great v essels and ac c ompanies t he ant erior border of t he psoas musc le int o t he pelv is. Injuries t o t he uret er near t he uret eropelv ic junc t ion c ommunic at e w it h t he perirenal spac e; disrupt ion slight ly more c audal produc es c ollec t ions on t he ant erolat eral surf ac e of t he psoas musc le.

Posterior Pararenal Space Lat eral t o t he lat eroc onal f asc ia, post erior t o t he renal f asc ia, but w it hin t he t ransv ersalis f asc ia lies t he post erior pararenal spac e, w hic h is c ont inuous w it h t he properit oneal f lank st ripe (36,154) (F ig. 10- 44). It c ont ains no organs, but is c losely relat ed t o t he post erior surf ac es of t he asc ending and desc ending c olon; inf lammat ory proc esses originat ing in t hese c olonic segment s (e.g., div ert ic ulit is, ret roc ec al appendic it is) hav e ready ac c ess t o t his spac e. T he post erior pararenal f at is c lose t o t he junc t ion of t he ant erior and post erior renal f asc ia, so f luid c ollec t ions c oursing w it hin t hese f asc ial pat hw ay s c an t rac k int o t he post erior pararenal spac e. In t his w ay , duodenal perf orat ions and panc reat it is ext end t o inv olv e t his anat omic region. Abov e t he lev el of t he renal hilus, t he post erior pararenal spac e is quit e small and post eriorly loc at ed. On sequent ially desc ending sec t ions, it ext ends ant eriorly and bec omes t hic ker. It s most import ant relat ionship is w it h a sec ond f at pad, separat e f rom t he post erior pararenal spac e, t hat lies immediat ely ant erior t o t he quadrat us lumborum musc le. T here is a f asc ial plane bet w een t he t w o f at pads, t hrough w hic h f luid in t he deeper ret roperit oneum esc apes post erolat erally t o reac h t he more superf ic ial t ransv ersalis f asc ia (56) (F ig. 10- 45). T his pat hw ay oc c urs t hrough t he lat eral

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1591

10 - Normal Abdominal and Pelvic Anatomy boundary of t he inf erior lumbar t riangle (t he Pet it t riangle). On sec t ions

c audal t o t he perirenal spac e, t he post erior pararenal f at c ont inues ant erior t o t he iliac us musc le and post erior t o t he asc ending or desc ending c olon.

Anterior Pararenal Space T he spac e bet w een t he ant erior renal f asc ia and t he post erior perit oneum is a c omplex area f ormed by f usion of t he dorsal mesent eries of t he st omac h (panc reat ic t ail and splenorenal ligament ), duodenum (mesoduodenum and head of panc reas), asc ending and desc ending c olon. T his spac e c ont ains most of t he duodenum, asc ending c olon, desc ending c olon, and panc reas; pat hologic proc esses arising w it hin any of t hese organs c an and do spread t o inv olv e t he ot her resident s of t he ant erior pararenal spac e. As w ell, t his spac e c ommunic at es readily w it h t he ligament s t hat embry ologic ally arose adjac ent t o it : t he root of t he small int est inal mesent ery ; t he root of t he t ransv erse mesoc olon; t he phrenic oc olic , duodenoc olic , and splenorenal ligament s; and t he lesser oment um. T his subperit oneal P.737 spread is a means by w hic h v ery aggressiv e proc esses, suc h as f ulminant panc reat it is, c an f ill t he mesent eries of t he upper abdomen (88) (F ig. 10- 46).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1592

10 - Normal Abdominal and Pelvic Anatomy

F igure 10- 36 Psoas spac es. A: Axial magnet ic resonanc e sec t ion just below t he aort ic bif urc at ion show s t he psoas musc le (PS) separat ed f rom t he v ert ebral body (V) by st rands of f at w it hin w hic h c ourse root s of t he lumbar plexus (ar r ow ) and t he lumbar v eins (ar r ow heads). Lat erally , t he psoas musc le is separat ed f rom t he quadrat us lumborum musc le by a f at plane t hat c ont ains t he lat eral f emoral c ut aneous nerv e. B: At t he lev el of t he iliac c rest , t he psoas musc le is div ided by t he f at - c ont aining psoas t endon (open ar r ow s). In t his groov e are t he f emoral nerv e (f n) and, more medially , t he obt urat or nerv e (on). T he f ibers of t he iliac us musc le (im) are beginning t o appear on t he right . lv , Lumbar v ein. C : Coronally rec onst ruc t ed c omput ed t omography show s t he origin of t he psoas musc le (ar r ow s) f rom t he t ransv erse proc esses of t he upper v ert ebrae, and it s int ra- abdominal ext ent . In t he pelv is, it joins w it h t he iliac us musc le (im) t o bec ome t he iliopsoas, t o insert inf eriorly on t he lesser t roc hant er of t he f emur. D: T hic k- slab v olumet ric rendering show s t he lumbar art eries (ar r ow s) c oursing bet w een t he v ert ebral body and t he psoas musc les w it hin t he psoas spac e.

Less f ulminant proc esses, how ev er, seem t o be c onf ined in predic t able subc ompart ment s w it hin int erf asc ial planes. A c ommon observ at ion in pat ient s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1593

10 - Normal Abdominal and Pelvic Anatomy

w it h moderat ely sev ere panc reat it is is panc reat ic ef f usion ext ending post erior t o t he panc reat ic t ail in t he ret romesent eric plane, w rapping around t he kidney , in t he ret rorenal plane, and c oursing ant erolat erally adjac ent t o t he desc ending c olon, in t he lat eroc onal plane. In t hese c ases, t he f at w it hin w hat w as originally t he dorsal desc ending mesoc olon is uninv olv ed, as is t he f at in t he post erior pararenal spac e. T his dist ribut ion suggest s a separat ion bet w een t he mesoc olic spac e and t he relat iv ely post erior panc reat ic oduodenal spac e (29) (F ig. 10- 47).

F igure 10- 37 Neurof ibromat osis t y pe I and t he psoas musc le. A: Axial sec t ion t hrough low er abdomen show s def ormit y of t he medial aspec t of bot h psoas musc les (pm) by a plexif orm neurof ibroma inv olv ing t he lumbar nerv e (ar r ow s). T here is a neurof ibroma in a lat eral c ut aneous spinal nerv e w it hin t he lef t erec t or spinae musc le (open ar r ow ). B: Sec t ion t hrough t he upper pelv is show s enlargement of t he sac ral nerv e root s (ar r ow heads). Neurof ibromas enlarge t he lumbar plexus (lp), t he genit of emoral nerv e (gf ) and t he f emoral nerv e (f ). C : Sec t ion t hrough t he pelv is show s inv olv ement of t he right sc iat ic nerv e (SC) and bot h obt urat or nerv es (ob). T here is sy mmet ric al enlargement of t he splanc hnic nerv es (spl) t hat c ourse w it hin t he mesorec t al f asc ia.

P.738

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1594

10 - Normal Abdominal and Pelvic Anatomy Pancreas, Duodenum, and Mesenteric Root T he panc reas arises f rom t w o sourc es: t he larger dorsal panc reas, w hic h originat es w it hin t he dorsal mesoduodenum, and t he v ent ral panc reas, w hic h

originally oc c upies t he v ent ral mesoduodenum. T he dorsal panc reas grow s in a post eroc ephalic direc t ion so t hat t he t ail c omes t o lie behind t he dev eloping spleen inside t he mesogast rium. T his segment of mesent ery subsequent ly f uses w it h t he post erior body w all on t he lef t . Meanw hile, t he panc reat ic head and apposed duodenum and dorsal mesoduodenum likew ise f use w it h t he post erior body w all on t he right . T he v ent ral panc reas rot at es 270 degrees around t he superior mesent eric v essels t o lie post erior and medial t o t he superior mesent eric v ein. T his most c audal port ion of t he panc reas is c alled t he unc inat e pr oc ess. T he panc reas is seldom imaged on a single t ransv erse sec t ion. As c ould be predic t ed f rom it s embry ology , sc ans near t he splenic hilus rout inely demonst rat e t he panc reat ic t ail (F ig. 10- 48). Panc reat ic t issue is c harac t erist ic ally somew hat lobular in out line and c ont ains ret roperit oneal f at in it s sulc i. T he splenic art ery and v ein lie post erior t o t he panc reat ic surf ac e. In y ounger indiv iduals, bot h v essels are st raight and parallel t o t he panc reat ic c ont our, separat ed f rom it by a t hin plane of f at . T he splenic art ery generally lies c ephalic and slight ly ant erior t o t he splenic v ein. Wit h age, t he splenic art ery bec omes t ort uous and may loop in any direc t ion on it s w ay t o t he splenic hilus; t he c ourse of t he splenic v ein is not alt ered. In a f ew indiv iduals, t he t ip of t he panc reat ic t ail c urls post eriorly t o lie behind t he splenic v essels. Anomalies of t he peripanc reat ic abdominal v essels are not unc ommon. T he rot at ion and f usion of t he dorsal mesoduodenum and mesogast rium c auses t he post erior surf ac e of t he panc reat ic body t o lie ant erior t o (and f use w it h) t he medial part of t he ant erior f asc ia of t he right kidney . A dome- shaped c ollec t ion of f at is t hus enc losed; t his f at is anat omic ally part of t he root of t he midgut mesent ery . T he spac e t hus f ormed is bounded by t he aort a and diaphragmat ic c rura post eriorly and t he panc reas and splenic v essels ant eriorly and lat erally . T he origin of t he superior mesent eric art ery is c ont ained w it hin it . Panc reat ic inf lammat ion t ends t o inv olv e adjac ent leav es of P.739

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1595

10 - Normal Abdominal and Pelvic Anatomy mesoduodenum or mesogast rium, sparing t he f at around t he superior mesent eric art ery ; c arc inoma of t he panc reas, how ev er, quit e c ommonly inf ilt rat es t his spac e t o enc ase t he art ery .

F igure 10- 38 F asc ial planes around t he kidney in a normal subjec t . A: T hic k slab axial v olume show s t he t y pic ally t hin ant erior renal f asc ia (ar r ow ) behind t he desc ending c olon mesent ery (ast er isk). T he f usion plane bet w een t he desc ending c olon (dc ) and t he post erior pararenal f at (pf ) is t he lat eroc onal f asc ia (open ar r ow ). T hese t w o f asc ial planes are c ont inuous w it h t he post erior renal f asc ia (ar r ow heads). B: T hic k- slab axial v olume approximat ely 2 c m inf erior t o (A) show s inc reased v olume of f at on t he post erolat eral aspec t of t he perirenal spac e. T he post erior renal f asc ia (ar r ow heads), on t he inner surf ac e of t he post erior pararenal spac e (pf ) ext ends bet w een t he desc ending c olon (dc ) and t he quadrat us lumborum musc le (ql). C : Sagit t al ref ormat t ed image in t he same subjec t show s t he c onic al shape of t he perirenal f at . T he ant erior renal f asc ia (ar r ow s) meet s t he post erior renal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1596

10 - Normal Abdominal and Pelvic Anatomy f asc ia (ar r ow heads) at t he apex of t he c one and c ont inues inf eriorly int o t he pelv is along t he surf ac e of t he psoas musc le (PM).

Alt hough t he superior mesent eric art ery is isolat ed f rom t he panc reas by an env elope of paraort ic f at , t he superior mesent eric v ein lies in t he not c h f ormed by t he junc t ion of t he head and nec k of t he panc reas, and only rarely is t here f at separat ing t hem. On sec t ions c audal t o t his junc t ion, t he unc inat e proc ess abut s t he post erolat eral and post erior surf ac e of t he superior mesent eric v ein. T he most post erior port ion of t he unc inat e proc ess lies immediat ely ant erior t o t he IVC; a f at plane is usually present bet w een t hem, but it s absenc e is not nec essarily pat hologic —it may not be present in t hin indiv iduals. Most c ommonly , on t he same sec t ion as t he inf erior margin of t he unc inat e proc ess, t he lef t renal v ein is depic t ed as it c rosses ant erior t o t he aort a and post erior t o t he superior mesent eric art ery t o drain in t he IVC. Ant erior and post erior t o t he head and unc inat e proc ess of t he panc reas lie t he panc reat ic oduodenal v eins, import ant landmarks in t he assessment of panc reat ic c arc inoma (25,95,148). T he gast roduodenal art ery , a f amiliar sonographic landmark, lies bet w een t he head of t he panc reas and t he ant roduodenal junc t ion (135). High- resolut ion CT sec t ions, in part ic ular t hose obt ained af t er int rav enous c ont rast enhanc ement , w ill somet imes depic t a normal panc reat ic duc t as a t hin ( T able of Cont ent s > 12 - Liv er

12 Liver Ja y P. He ike n C hristine O. Me nia s Kha le d Elsa y e s F or more t han 25 y ears, c omput ed t omography (CT ) has been w idely used f or ev aluat ing bot h f oc al and dif f use hepat ic diseases. It has bec ome est ablished as t he imaging met hod of c hoic e f or rout ine sc reening of t he liv er. How ev er, magnet ic resonanc e imaging (MRI) has prov ed t o be at least as ef f ec t iv e as int rav enous c ont rast - enhanc ed CT f or det ec t ing and c harac t erizing most hepat ic abnormalit ies. Eac h met hod has st rengt hs and limit at ions. Regardless of t he imaging met hod used, how ev er, t he t ec hnique of c onduc t ing t he examinat ion is c ruc ial t o it s diagnost ic perf ormanc e. T his c hapt er highlight s t he use of CT and MRI f or ev aluat ing bot h f oc al and dif f use hepat ic abnormalit ies. Various CT and MRI t ec hniques are disc ussed, and t he rat ionale f or c hoosing among t hem in dif f erent c linic al sit uat ions is explained. T he c linic ally relev ant anat omy of t he liv er and t he CT and MRI appearanc es of import ant pat hologic proc esses inv olv ing t he liv er are det ailed.

ANATOMY Gross Morphology T he liv er is t he largest organ in t he abdomen, oc c upy ing most of t he right upper quadrant . It v aries c onsiderably among indiv iduals in size and c onf igurat ion. Superiorly , lat erally , and ant eriorly t he liv er is bordered by and c onf orms t o t he undersurf ac e of t he diaphragm. Prominent diaphragmat ic leav es may indent t he surf ac e of t he liv er as t hey insert on t he ribs, produc ing hy poat t enuat ing or low - signal- int ensit y def ec t s t hat should not be

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1781

12 - Liver misint erpret ed as int rahepat ic lesions (19) (F ig. 12- 1). T he liv er is bordered medially by t he st omac h, duodenum, and t ransv erse c olon, inf eriorly by t he hepat ic f lexure of t he c olon, and post eriorly by t he right kidney . T he superior port ion of t he right adrenal gland borders t he medial aspec t of t he post erior superior right hepat ic segment (segment VII). T he liv er is c ov ered by perit oneum, exc ept f or t he surf ac es apposed t o t he

inf erior v ena c av a (IVC), t he gallbladder f ossa, and t he post erosuperior aspec t of t he diaphragm (t he “ bare area” ). It is at t ac hed t o t he diaphragm ant erosuperiorly by t he f alc if orm ligament and post eriorly by t he c oronary ligament s. T he surf ac e of t he liv er bet w een t he superior and inf erior c oronary ligament s is dev oid of perit oneum and is ref erred t o as t he “ bare area.” Bec ause of t he lac k of perit oneum on t his hepat ic surf ac e, perit oneal f luid c annot ac c umulat e bet w een t he liv er and t he diaphragm in t his area. F luid ident if ied post erior t o t he liv er in t his region is loc at ed in t he pleural spac e (425), in t he superior rec ess of t he ret roperit oneum, or beneat h t he liv er c apsule. Lat erally t he superior and inf erior c oronary ligament s c ome t oget her t o f orm t he lef t and right t riangular ligament s. T hree hepat ic f issures help def ine t he margins of t he hepat ic lobes and t he major hepat ic segment s (148). T he int erlobar f issure is an inc omplet e st ruc t ure on t he inf erior margin of t he liv er t hat is orient ed along a line passing t hrough t he gallbladder f ossa inf eriorly and t he middle hepat ic v ein superiorly (727) (F ig. 12- 2). Alt hough it is w ell def ined in some pat ient s, it may be dif f ic ult t o ident if y in ot hers. T he int erlobar f issure f orms t he inf erior margin of t he border bet w een t he right and lef t hepat ic lobes. T he lef t int ersegment al f issure (f issure f or t he ligament um t eres), w hic h f orms a w elldef ined sagit t ally orient ed c lef t in t he c audal aspec t of t he lef t hepat ic lobe, div ides t he lobe int o medial and lat eral segment s (F igs. 12- 2 and 12- 3). T he ligament um t eres, w hic h is usually surrounded by a small amount of f at , runs t hrough t he f issure af t er ent ering it v ia t he f ree margin of t he f alc if orm ligament . A t hird f issure, t he f issure f or t he ligament um v enosum, is orient ed in a c oronal or oblique plane bet w een t he post erior aspec t of t he lef t lat eral hepat ic segment and t he ant erior aspec t of t he c audat e lobe (see F igs. 12- 2 and 12- 3). T his f issure, P.830 P.831

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1782

12 - Liver w hic h is in c ont inuit y w it h t he int ersegment al f issure, c ont ains a port ion of t he gast rohepat ic ligament (lesser oment um). It is best seen on images obt ained c ephalad t o t he f issure f or t he ligament um t eres.

F igure 12- 1 Hepat ic pseudolesion. Cont rast - enhanc ed CT image A: show s a low at t enuat ion def ec t in t he medial segment of t he lef t hepat ic lobe (ar r ow ). A more c ephalad image B: demonst rat es t hat t he appearanc e is due t o indent at ion f rom t he adjac ent diaphragm.

F igure 12- 2 Hepat ic segment al anat omy as v iew ed in t he t ransaxial plane at dif f erent lev els t hrough t he liv er. T he t ransv erse sc issura, desc ribed by t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1783

12 - Liver

lef t and right port al v ein branc hes, demarc at es t he c ranially loc at ed segment s (II, VII, and VIII) f rom t he c audally loc at ed segment s (III, VI, and V, respec t iv ely ). RHV, right hepat ic v ein; MHV, middle hepat ic v ein; LHV, lef t hepat ic v ein; PV, port al v ein; IVC, inf erior v ena c av a; F LT , f issure f or t he ligament um t eres; F LV, f issure f or t he ligament um v enosum; RPV, right port al v ein (A, ant erior branc h; P, post erior branc h); LPV, lef t port al v ein; U, umbilic al segment ; F L, f alc if orm ligament ; ILF , int erlobar f issure; GB, gallbladder.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

12 - Liver

Computed Body Tomography with MRI Correlation , 4th Edition

1784

© 2017 Enter your company name

1785

12 - Liver F igure 12- 3 Hepat ic segment al and v enous anat omy as depic t ed by CT A– L. Tra nsa x ia l ima ge s A– F : T he main hepat ic v eins (blac k

ar r ow heads, A– F ) f orm t he major v ert ic al sc issurae t hat div ide t he hepat ic segment s. T he right and lef t port al v eins, show n in C , f orm t he t ransv erse sc issura. Open ar r ow , f issure f or t he ligament um v enosum; c ur v ed ar r ow , umbilic al segment of lef t port al v ein; st r aight ar r ow , f issure f or t he ligament um t eres; PV, port al v ein; LPV, lef t port al v ein; RPV, right port al v ein; LLPV, lef t lat eral segment port al v ein branc h; ARPV, ant erior branc h of right port al v ein; PRPV, post erior branc h of t he right port al v ein. Whit e ar r ow , ac c essory right hepat ic v ein. Cur v ed open ar r ow , int erlobar f issure. T he hepat ic segment s are numbered ac c ording t o t he sy st em of Couinaud as modif ied by Bismut h. (c ont inued) C orona l ima ge s (G– L) orde re d from most a nte rior (G) to most poste rior (L): T he hepat ic segment s are numbered ac c ording t o t he sy st em of Couinaud as modif ied by Bismut h. G: Ar r ow , lef t lat eral port al v ein branc h t o segment III. Ar r ow heads, lef t hepat ic v ein branc hes draining segment s II and III. Cur v ed ar r ow , f issure f or t he ligament um t eres. Open ar r ow , int erlobar f issure (gallbladder f ossa). H: Ar r ow , umbilic al segment of t he lef t port al v ein. Cur v ed ar r ow , lef t hepat ic v ein. Ar r ow head, middle hepat ic v ein. Open ar r ow , int erlobar f issure (gallbladder f ossa). Whit e ar r ow , right ant erior segment port al v ein branc h. I: Ar r ow , umbilic al segment of t he lef t port al v ein. Cur v ed ar r ow , lef t hepat ic v ein. Ar r ow head, middle hepat ic v ein. Open ar r ow , lef t lat eral port al v ein branc h t o segment II. J: PV, main port al v ein. RPV, right port al v ein. LPV, lef t port al v ein. Ar r ow , lef t hepat ic v ein. Ar r ow head, middle hepat ic v ein. K: Cur v ed ar r ow , lef t hepat ic v ein. Ar r ow head, middle hepat ic v ein. PV, main port al v ein. RPV, right port al v ein. (c ont inued) L: IVC, inf erior v ena c av a. Ar r ow , right hepat ic v ein. Images prepared by Bret t Grat z, MD.

T he c audat e lobe may be c onsidered an aut onomous part of t he liv er f rom a f unc t ional v iew point bec ause it has separat e blood supply , bile drainage, and v enous drainage f rom t he rest of t he liv er (148). It is a pedunc ulat ed port ion P.832 P.833 of t he liv er t hat ext ends medially f rom t he right lobe bet w een t he IVC and port al v ein (see F igs. 12- 2 and 12- 3). T he ist hmus, w hic h oc c upies t he posit ion bet w een t he port al v ein and v ena c av a, is ref erred t o as t he c audat e proc ess. T he more medial ext ension is c alled t he papillary proc ess. Below t he port a hepat is, t he papillary proc ess may appear separat e f rom t he rest of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1786

12 - Liver liv er and may be mist aken f or an enlarged ly mph node (18,162). Mult iplanar v iew ing or c aref ul analy sis of c onsec ut iv e CT or MRI sec t ions is essent ial t o av oid t his pot ent ial pit f all.

Segmental Anatomy An underst anding of t he segment al anat omy of t he liv er is c rit ic al f or loc alizat ion and appropriat e management of hepat ic neoplasms. Conf usion regarding hepat ic segment al anat omy relat es primarily t o dif f erenc es bet w een Americ an and European nomenc lat ure (754). T he sy st em proposed by Goldsmit h and Woodburne (242) and used by most Americ an radiologist s does not prov ide a lev el of det ail adequat e f or t he surgic al planning of subsegment al hepat ic resec t ions. T hat proposed by Couinaud (139) and lat er modif ied by Bismut h (54) prov ides t he surgic ally relev ant inf ormat ion and is easily applic able t o c ross- sec t ional imaging t ec hniques suc h as CT , MRI, and ult rasound (754). T able 12- 1 show s t he c orrespondenc e among t hese t hree nomenc lat ures. An addit ional nomenc lat ure adopt ed at t he World Congress of t he Int ernat ional Hepat o- Panc reat o- Biliary Assoc iat ion in Brisbane, Aust ralia in 2000 (786) also w ill be desc ribed.

TABLE 12- 1 ANATOMIC SEGMENTS OF THE LIVER AND C ORRESPONDING NOMENC LATURE

T he sy st em of Goldsmit h and Woodburne is t he most basic and div ides t he liv er int o right and lef t lobes, w it h eac h lobe hav ing t w o segment s. T he right lobe c onsist s of ant erior and post erior segment s, w hereas t he lef t c onsist s of medial and lat eral segment s. A smaller, anat omic ally dist inc t c audat e lobe deriv es it s art erial supply f rom bot h t he right and lef t hepat ic art eries, and it s v enous blood drains direc t ly int o t he IVC. T he right and lef t lobes are div ided

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1787

12 - Liver by a v ert ic al (c ephaloc audal) plane passing f rom t he gallbladder f ossa

inf eriorly t o t he middle hepat ic v ein superiorly . T he plane is orient ed obliquely f rom t he gallbladder f undus ant eriorly t o t he IVC post eriorly (see F ig. 12- 2). T he ant erior and post erior segment s of t he right lobe are div ided by a v ert ic al plane t hrough t he right hepat ic v ein. T he medial and lat eral segment s of t he lef t lobe are div ided by a v ert ic al plane t hrough t he f issure f or t he ligament um t eres inf eriorly and t he lef t hepat ic v ein superiorly . T hus, t he main hepat ic v eins run bet w een hepat ic segment s, and c ephaloc audal planes draw n t hrough t he main hepat ic v eins div ide t he major hepat ic segment s (see F ig. 12- 2). T he right hepat ic v ein lies bet w een t he ant erior P.834 and post erior segment s of t he right lobe, t he middle hepat ic v ein bet w een t he right and lef t lobes, and t he lef t hepat ic v ein bet w een t he medial and lat eral segment s of t he lef t lobe. In c ont radist inc t ion, t he int rahepat ic port al t riads, c onsist ing of branc hes of t he port al v ein, hepat ic art eries, and bile duc t s, c ourse t hrough t he c ent ral port ions of t he hepat ic segment s. In t he t radit ional hepat ic segment al nomenc lat ure desc ribed abov e, no dist inc t ion is made bet w een superior and inf erior subsegment s w it hin eac h major segment . Bec ause surgic al t ec hniques allow ing resec t ion of suc h subsegment s hav e been dev eloped, it is import ant t o dist inguish t hese hepat ic subdiv isions f or more prec ise lesion loc alizat ion. In t he nomenc lat ure of Couinaud, t he hepat ic segment s, exc ept f or t he c audat e lobe and medial segment of t he lef t lobe, are def ined not only by t he t hree v ert ic al sc issurae desc ribed by t he major hepat ic v eins but by a t ransv erse sc issura desc ribed by t he right and lef t port al v ein branc hes (F ig. 12- 4). T hus, ac c ording t o t his sy st em, eight segment s are def ined. Segment I is t he c audat e lobe, and segment s II t hrough VIII are numbered in a c loc kw ise direc t ion w hen t he liv er is v iew ed f rom it s v ent ral aspec t (see F ig. 12- 4 and T able 12- 1). Eac h segment has an independent v asc ular supply and biliary drainage (148). T he modif ic at ion by Bismut h div ides segment IV int o superior (IVa) and inf erior (IVb) subsegment s. T he Brisbane 2000 T erminology of Liv er Anat omy (786) div ides t he liv er int o a right hemiliv er (Couinaud segment s V–VIII, ± segment I) and lef t hemiliv er (segment s II–IV, ± segment I), c orresponding t o t he t radit ional right and lef t hepat ic “ lobes.” T he t erm f or t he sec ond order div isions in t his nomenc lat ure is “ sec t ion,” w hic h c orresponds t o t he t radit ional “ segment .” F or example, t he right hemiliv er c onsist s of ant erior and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1788

12 - Liver post erior sec t ions, w hereas t he lef t hemiliv er c onsist s of medial and lat eral sec t ions. T he t hird order div isions are t ermed “ segment s,” w hic h c orrespond t o t he numbered Couinaud segment s.

Vascular Anatomy T he af f erent v essels of t he liv er are t he hepat ic art eries and port al v eins, w hic h ent er t he liv er at t he hilum (port a hepat is) and branc h in a rec ognizable pat t ern w it hin t he liv er parenc hy ma. T hey are ac c ompanied by c orresponding branc hes of t he bile duc t s w it h w hic h t hey f orm t he port al t riads. T he hepat ic v eins are t he ef f erent v essels of t he liv er. T hey run separat ely f rom t he af f erent v essels and drain direc t ly int o t he IVC. T he por t al v ein originat es post erior t o t he nec k of t he panc reas at t he c onf luenc e of t he superior mesent eric and splenic v eins. It passes post erior t o t he bile duc t s and hepat ic art ery w it hin t he hepat oduodenal ligament (f ree edge of t he lesser oment um) as it proc eeds t ow ard t he port a hepat is (see F ig. 12- 3E). At t he port a hepat is t he port al v ein div ides int o right and lef t branc hes (see F ig. 12- 3C, D), w hic h c ourse alongside t he right and lef t hepat ic art eries and bile duc t s. T he init ial port ion of t he right port al v ein c ourses right w ard and c ranially , giv ing of f sev eral branc hes t hat supply t he port a hepat is and c audat e lobe. Wit hin t he subst anc e of t he right lobe t he right port al v ein div ides int o ant erior and post erior branc hes t hat supply t he c orresponding hepat ic segment s (see F ig. 12- 3C, D). Eac h of t hese v essels div ides again int o superior and inf erior branc hes t hat supply t he superior and inf erior subdiv isions of t heir respec t iv e hepat ic segment s (see F ig. 12- 4). T he init ial port ion of t he lef t port al v ein (pars t ransv ersa) passes horizont ally t o t he lef t , giv ing of f branc hes t hat supply t he lat eral segment (segment s II and III) bef ore t urning medially t o join t he oblit erat ed umbilic al v ein w it hin t he f issure f or t he ligament um t eres. T his int raf issural port ion (umbilic al segment ) of t he lef t port al v ein (see F ig. 12- 3B) ext ends c ranially , t erminat ing in asc ending and desc ending branc hes t hat supply t he superior and inf erior div isions of segment IV.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1789

12 - Liver

F igure 12- 4 Diagrammat ic illust rat ion of hepat ic segment al anat omy . As desc ribed by Couinaud, t he liv er c onsist s of eight f unc t ional hepat ic segment s, w hic h are numbered in a c loc kw ise direc t ion w hen t he liv er is v iew ed f rom it s v ent ral aspec t . Eac h segment has a prec ise art erial supply , v enous drainage, and biliary duc t al drainage. T he main hepat ic v eins run bet w een hepat ic segment s. (Adapt ed f rom Ger R. Surgic al anat omy of t he liv er. Sur g Clin Nor t h Am . 1989;69:179–192.)

T he hepat ic ar t er y prov ides only 25% t o 30% of t he af f erent hepat ic blood f low but c arries approximat ely 50% of av ailable oxy gen (148). T he c ommon hepat ic art ery usually arises as a branc h of t he c eliac axis, c oursing ant eriorly and t o t he right t o ent er t he lesser oment um. Af t er giv ing of f right gast ric and gast roduodenal branc hes, it c ont inues P.835 w it hin t he hepat oduodenal ligament as t he proper hepat ic art ery . On images obt ained at t he lev el of t he port a hepat is, t he hepat ic art ery and bile duc t c an be ident if ied ant erior t o t he port al v ein, w it h t he art ery usually oc c upy ing a more medial posit ion t han t he duc t . Wit hin t he port a hepat is t he proper hepat ic art ery div ides int o right and lef t branc hes. T his c lassic arrangement of hepat ic art erial anat omy is present in only slight ly more t han half of subjec t s, w it h up t o 45% hav ing one or more v ariat ions (530). T he t w o most c ommon v ariat ions are origin of t he lef t hepat ic art ery f rom t he lef t gast ric art ery and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1790

12 - Liver

origin of all or some right hepat ic art ery branc hes f rom t he superior mesent eric art ery . Wit hin t he liv er, t he right and lef t hepat ic art ery branc hes div ide in a f ashion similar t o t hat of t he port al v ein branc hes t o supply t heir c orresponding segment s. T he hepat ic v eins drain int o t he IVC. T he t hree main hepat ic v eins—right , middle, and lef t —lie w it hin t he post erosuperior aspec t of t he liv er and drain int o t he IVC just below t he diaphragm (see F ig. 12- 2). In addit ion t o t he main v enous t runks, a v ariable number of smaller dorsal hepat ic v eins drain f rom t he post erior aspec t of t he right lobe and c audat e lobe (segment I) direc t ly int o t he IVC. T he right hepat ic v ein (see F igs. 12- 2 and 12- 3), w hic h lies bet w een t he right ant erior and post erior hepat ic segment s, drains segment s V, VI, and VII (148). T he middle hepat ic v ein (see F igs. 12- 2 and 12- 3), w hic h lies in t he int erlobar plane, drains primarily segment s IV, V, and VIII. T he lef t hepat ic v ein (see F igs. 12- 2 and 12- 3), w hic h c ourses in t he sagit t al plane bet w een t he medial and lat eral segment s of t he lef t lobe, drains segment s II and III. In about 90% of c ases, t he middle and lef t hepat ic v eins join t o f orm a c ommon t runk bef ore empt y ing int o t he IVC (569).

Hepatic Parenchyma On bot h CT and MR images normal hepat ic parenc hy ma has a homogeneous appearanc e. T he at t enuat ion v alue of normal liv er parenc hy ma on unenhanc ed CT v aries c onsiderably among indiv iduals, but generally it is in t he range of 45 t o 65 HU. In normal adult s, t he at t enuat ion v alue of t he liv er on unenhanc ed images is c onsist ent ly higher t han t hat of t he spleen, w it h a mean dif f erenc e of 8 HU (641). T his hepat ic - splenic at t enuat ion dif f erenc e is due t o t he high c onc ent rat ion of gly c ogen w it hin t he liv er (173). Af t er int rav enous administ rat ion of c ont rast mat erial, how ev er, t he at t enuat ion v alue of t he liv er of t en bec omes less t han t hat of t he spleen, w it h t he amount of dif f erenc e depending on t he t iming of image ac quisit ion and t he met hod of c ont rast medium administ rat ion. T his normal post c ont rast c hange in t he relat iv e at t enuat ion v alues of liv er and spleen should not be misint erpret ed as an indic at ion of hepat ic st eat osis. On T 1- w eight ed MR images, t he normal liv er has an int ermediat e signal int ensit y , similar t o t hat of t he panc reas but higher t han t hat of t he spleen. T he dif f erenc e in signal int ensit y bet w een t he liv er and spleen c an be used as a rough measure of t he degree of T 1 w eight ing (t he great er t he dif f erenc e, t he great er t he T 1 w eight ing) (204). On T 2- w eight ed images t he liv er has a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1791

12 - Liver low er signal int ensit y , higher t han t hat of musc le but less t han t hat of t he spleen. Hepat ic v essels appear v ery low in signal int ensit y on T 1- w eight ed images due t o f low - relat ed signal loss. How ev er, on T 2- w eight ed images t he v essels may hav e high signal int ensit y ow ing t o f low - relat ed enhanc ement .

Anatomic Variants and Anomalies T he import anc e of rec ognizing anat omic v ariant s of liv er morphology is t o av oid misint erpret ing t hem as pat hology . A c ommon v ariant is t he presenc e of one or more inc omplet e ac c essory hepat ic f issures f ormed by inv aginat ions of t he diaphragm (19). T hese are seen most c ommonly in t he right lobe superiorly and should not be mist aken f or peripheral hepat ic pat hology . In some pat ient s a lef t w ard ext ension of t he lat eral segment of t he lef t hepat ic lobe projec t s post eriorly t o w rap around t he spleen. Know ledge of t his v ariant is import ant t o av oid mist aking pat hology in t his port ion of t he liv er f or diseases originat ing in t he st omac h or spleen. T rue c ongenit al anomalies of t he liv er are rare (104). T hey c an be c at egorized int o t w o t y pes: t hose c aused by def ec t iv e dev elopment and t hose c aused by exc essiv e dev elopment (104). T he most c ommon anomaly , Riedel's lobe, is due t o exc essiv e dev elopment . More c ommon in w omen, it represent s a sessile ac c essory lobe t hat ext ends c audally f rom t he inf erior aspec t of t he right lobe and of t en has a bulbous c onf igurat ion. Anomalies c aused by def ec t iv e dev elopment of a hepat ic lobe or segment may be c harac t erized by absenc e (agenesis), small size w it h normal st ruc t ure (hy poplasia), or small size w it h abnormal st ruc t ure (aplasia) (104). Suc h anomalies generally af f ec t an ent ire lobe (41,350,357,663,883), but rarely may af f ec t just one segment (619). T hey must be dist inguished f rom lobar at rophy t hat dev elops as a c onsequenc e of ac quired v asc ular or biliary disease (143,158).

Appearance After Partial Hepatectomy T he appearanc e of t he liv er af t er part ial hepat ec t omy depends on t he segment or lobe resec t ed, t he operat iv e t ec hnique used, and t he amount of hepat ic regenerat ion (447). Liv er t issue may regenerat e quit e rapidly af t er part ial hepat ic resec t ion, a proc ess t hat c ont inues f or 6 mont hs t o 1 y ear, as demonst rat ed by progressiv e hepat ic enlargement ov er t his period (138). A small region of low at t enuat ion at t he surgic al margin is of t en present , likely

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1792

12 - Liver

represent ing a t ransient ac c umulat ion of blood and bile (447). F at at t enuat ion at t he resec t ion margin represent s t he oment al pat c h plac ed at surgery (447). P.836

COMPUTED TOMOGRAPHY IMAGE ACQUISITION CONSIDERATIONS As w ill be disc ussed in subsequent sec t ions, liv er lesion det ec t ion depends on a v ariet y of f ac t ors, inc luding int rinsic c harac t erist ic s of t he lesion, c ont rast enhanc ement t ec hniques, and sc an t iming. In addit ion t o t hese f ac t ors, how ev er, t he t ec hnic al paramet ers used t o ac quire t he image dat a play a v ery import ant role in lesion det ec t ion. Part ial v olume av eraging and image noise may int erf ere w it h our abilit y t o disc ern small lesions. Part ial v olume av eraging c an be minimized by using narrow sec t ion w idt h and rec onst ruc t ing ov erlapping sec t ions. How ev er, t hinner sec t ions inc rease image noise, w hic h c an int erf ere w it h lesion det ec t ion. Wit h single det ec t or- row sc anners, c ollimat ion should be no great er t han 5 mm, exc ept in obese pat ient s, and a pit c h of 1.5 c an be used t o prov ide adequat e v olume c ov erage. Rec onst ruc t ion of sec t ions t hat ov erlap by 25% t o 50% improv es det ec t ion of small liv er lesions (818). F or dedic at ed mult iphase liv er imaging st udies, 3- mm c ollimat ion w it h a pit c h of 1.5 t o 2.0 c an be used if 3D v asc ular rec onst ruc t ions are required. Rec onst ruc t ion of ov erlapping sec t ions improv es t he qualit y of t he 3D images. An import ant adv ant age of MDCT sc anners is t hat f rom t he same dat a set , t hin sec t ions c an be rec onst ruc t ed t o minimize part ial v olume av eraging and t hic ker sec t ions c an be rec onst ruc t ed t o dec rease image noise, if nec essary . F or 4 det ec t or- row sc anners, a det ec t or c onf igurat ion of 4 × 2.5 mm is rec ommended f or rout ine liv er sc reening, w it h 4 × 1–1.25 mm det ec t or c onf igurat ion reserv ed f or dedic at ed mult iphase imaging in w hic h high- qualit y 3D rec onst ruc t ions are needed. Wit h 16 det ec t or- row sc anners, st andard examinat ions c an be perf ormed w it h 16 × 1.25–1.5 mm det ec t or c onf igurat ion and st aging or pre- operat iv e ev aluat ion st udies w it h 16 × 0.625–0.75 mm det ec t or c onf igurat ion. Wit h 64- det ec t or- row sc anners, all st udies c an be perf ormed w it h 0.6–0.625 det ec t or c ollimat ion and images of v arious sec t ion t hic knesses rec onst ruc t ed as needed.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1793

12 - Liver T he opt imal sec t ion t hic kness f or v iew ing liv er images ac quired w it h MDCT sc anners remains t o be det ermined. T w o st udies hav e show n t hat more liv er lesions c an be det ec t ed w it h 2.5- mm slic e t hic kness t han w it h 5.0- mm slic e

t hic kness (257,855), alt hough most of t he addit ional lesions ident if ied w it h t he t hinner slic es may be benign (257). On t he ot her hand, a phant om st udy has demonst rat ed t hat MDCT w it h less t han 5- mm sec t ion t hic kness is less ef f ec t iv e in depic t ing low - c ont rast objec t s t han MDCT w it h 5- mm sec t ion t hic kness (831). F urt her st udy is needed t o resolv e t he issue of t he opt imum sec t ion t hic kness f or det ec t ing small liv er lesions w it h MDCT . F or t he t ime being, 5- mm slic e t hic kness appears adequat e f or rout ine liv er sc reening, w it h t hinner sec t ions rec onst ruc t ed f rom t he MDCT dat a set as needed. F or dedic at ed mult iphase liv er prot oc ols, rec onst ruc t ion of t hin (1- t o 2- mm) sec t ions is pref erable t o enable high- qualit y 3D and mult iplanar rec onst ruc t ions. T hic ker sec t ions c an be rec onst ruc t ed f rom t he MDCT dat a set f or ease of rev iew . When imaging obese pat ient s, high lev els of image noise c an int erf ere w it h liv er lesion det ec t ion. Modif ic at ions t hat c an be used t o reduc e image noise in t his group of pat ient s inc lude (a) inc reasing t he x- ray t ube c urrent and t he sc an t ime used t o ac quire t he images and (b) rec onst ruc t ing t hic ker sec t ions. As w ill be disc ussed lat er, v ery large pat ient s also require a larger dose of int rav enous c ont rast medium.

PRINCIPLES OF HEPATIC CONTRAST ENHANCEMENT T he primary purpose of administ ering an int rav asc ular c ont rast agent f or hepat ic CT is t o inc rease t he at t enuat ion v alue dif f erenc e bet w een liv er lesions and normal hepat ic parenc hy ma. T he diagnost ic ef f ec t iv eness of t he result ing CT examinat ion is dependent on t he c ont rast medium dose, t he met hod of c ont rast medium administ rat ion, and sc an t iming. In addit ion, pat ient f ac t ors suc h as w eight and c ardiac out put hav e import ant ef f ec t s on t he magnit ude and t iming of hepat ic enhanc ement , respec t iv ely . In t his sec t ion, t he phy siologic princ iples of hepat ic c ont rast enhanc ement are present ed. Normal unenhanc ed liv er parenc hy ma has an at t enuat ion v alue of 45 t o 65 HU (641,676,778). T he mean at t enuat ion v alue of hepat ic neoplasms v aries

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1794

12 - Liver c onsiderably , being dependent on mult iple f ac t ors inc luding hist ology , v asc ularit y , and t he presenc e of areas of nec rosis, c alc if ic at ion, hemorrhage,

or f at t y degenerat ion. Most hepat ic neoplasms hav e a low er at t enuat ion v alue t han normal hepat ic parenc hy ma. How ev er, if dif f use f at t y met amorphosis of t he liv er parenc hy ma is present , neoplasms may be isoat t enuat ing or hy perat t enuat ing. A neoplasm may be indisc ernible if it s at t enuat ion dif f erenc e f rom t he surrounding hepat ic parenc hy ma is less t han 10 HU. When a c ont rast agent is administ ered int rav enously , it rapidly redist ribut es f rom t he v asc ular t o t he ext rav asc ular (int erst it ial) spac e, w hile being c ont inuously exc ret ed by t he kidney s (85,397). In t he liv er t his proc ess oc c urs quit e rapidly , and short ly af t er an int rav enous c ont rast medium injec t ion has ended, a subst ant ial amount of t he hepat ic parenc hy mal enhanc ement is c ont ribut ed by int erst it ial c ont rast mat erial ac c umulat ion (210). Hepat ic c ont rast enhanc ement is best underst ood by c onsidering t he t hree phases of hepat ic enhanc ement (v asc ular, redist ribut ion, and equilibrium) (210), eac h of w hic h c orresponds t o a dif f erent port ion of t he aort ic –hepat ic t ime- at t enuat ion c urv e (F ig. 12- 5). T he v asc ular phase represent s t he period of int rav enous c ont rast medium injec t ion int o t he c ent ral blood c ompart ment and is c harac t erized by a rapid rise in aort ic enhanc ement t hat reac hes a peak short ly af t er t he end of t he c ont rast medium injec t ion (23,24). During t his P.837 phase hepat ic parenc hy mal enhanc ement inc reases gradually . During t he redist ribut ion phase, c ont rast mat erial dif f uses f rom t he c ent ral blood c ompart ment t o t he ext rav asc ular c ompart ment of t he liv er. T his redist ribut ion result s in a rapid dec rease in aort ic enhanc ement and a c onc omit ant inc rease in hepat ic enhanc ement , indic at ing t hat most normal hepat ic parenc hy mal enhanc ement is due t o ext rav asc ular c ont rast mat erial ac c umulat ion. T he plat eau of peak hepat ic parenc hy mal enhanc ement is c ommonly ref erred t o as t he port al v enous phase or hepat ic parenc hy mal phase of enhanc ement . T he equilibrium phase oc c urs w hen c ont rast medium slow ly dif f uses f rom t he liv er bac k int o t he c ent ral v asc ular c ompart ment , result ing in a gradual dec line in hepat ic enhanc ement . Aort ic enhanc ement also gradually dec lines during t his phase as c ont rast medium c ont inuously exit s t he v asc ular c ompart ment t hrough glomerular f ilt rat ion and dif f usion int o less w ell- perf used organs, suc h as skelet al musc le and f at . Many hepat ic lesions bec ome obsc ured during t his phase bec ause t here is no subst ant ial dif f erenc e in int erst it ial ac c umulat ion of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1795

12 - Liver c ont rast mat erial bet w een t he lesions and t he normal hepat ic parenc hy ma (210,633). How ev er, some lesions suc h as hepat oc ellular c arc inoma may bec ome more apparent during t he equilibrium phase as t heir int erst it ial enhanc ement diminishes relat iv e t o t hat of t he surrounding hepat ic parenc hy ma (462,541).

F igure 12- 5 Phases of hepat ic c ont rast enhanc ement . Simulat ed c ont rast enhanc ement c urv es of t he aort a and liv er f or a 150- pound man rec eiv ing 150 mL of a 320 mg I/mL c ont rast agent at 5 mL/ sec ond. T he v asc ular phase (1) represent s t he period of int rav enous c ont rast medium injec t ion int o t he c ent ral blood c ompart ment and is c harac t erized by a rapid rise in aort ic enhanc ement t hat reac hes a peak short ly af t er t he end of t he c ont rast medium injec t ion. During t his phase, hepat ic enhanc ement inc reases slow ly . T he r edist r ibut ion phase (2) is c harac t erized by a rapid dec rease in aort ic enhanc ement and an ac c ompany ing inc rease in hepat ic enhanc ement . During t he equilibr ium phase (3) aort ic and hepat ic enhanc ement undergo a gradual parallel dec line.

T he c onc ept of equilibrium as it relat es t o c ont rast enhanc ement (21,149,844) w as muc h more import ant in t he pre–helic al CT era w hen hepat ic sc an

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1796

12 - Liver durat ions w ere rout inely longer t han 1 minut e. T he short sc an durat ions of abdominal helic al CT , part ic ularly mult idet ec t or- row CT (MDCT ), hav e eliminat ed t he risk of imaging t he liv er during t he equilibrium phase and obsc uring liv er lesions, if proper sc an t iming is used.

Magnitude of Hepatic Enhancement T he magnit ude of hepat ic parenc hy mal enhanc ement is det ermined by a c ombinat ion of f ac t ors. T he most import ant t ec hnique- relat ed f ac t ors are t ot al iodine dose, w hic h is det ermined by t he c ont rast medium v olume (44,102,155,275) and c onc ent rat ion (275), and t he rat e of injec t ion (44,102,103,131,155,267,274,275). F or a giv en injec t ion rat e, t he magnit ude of peak hepat ic c ont rast enhanc ement inc reases linearly w it h t he dose of iodine administ ered (23,27). Use of c ont rast medium w it h a higher iodine c onc ent rat ion improv es hepat ic parenc hy mal enhanc ement t o t he ext ent t hat it inc reases ov erall iodine dose (225). T he magnit ude of hepat ic parenc hy mal enhanc ement also inc reases w it h f ast er injec t ion rat es but in a nonlinear f ashion. Inc reases in injec t ion rat e result in subst ant ially inc reased peak hepat ic parenc hy mal enhanc ement w it h rat es up t o approximat ely 2 mL/sec ond (24). Abov e 2 mL per sec ond, inc reases in injec t ion rat e result in relat iv ely small addit ional hepat ic parenc hy mal enhanc ement inc reases (230). Rapid injec t ion rat es (e.g., 4 t o 5 mL per sec ond) do, how ev er, result in inc reased hepat ic art erial enhanc ement and great er separat ion of t he peaks of aort ic and hepat ic enhanc ement (24,333,384). T hese benef it s of rapid c ont rast medium injec t ion rat e are helpf ul w hen mult iphase helic al CT is used f or t he det ec t ion of v asc ular hepat ic neoplasms (541). T he most import ant pat ient - relat ed f ac t or af f ec t ing t he magnit ude of hepat ic c ont rast enhanc ement is body w eight (275,398). Maximum hepat ic enhanc ement dec reases w it h inc reasing pat ient w eight (275,398). Alt hough diminished c ardiac out put c auses delay ed aort ic and hepat ic enhanc ement , it does not diminish t he magnit ude of hepat ic enhanc ement (22).

Timing of Hepatic Enhancement T he liv er rec eiv es approximat ely 75% of it s blood supply f rom t he port al v ein and t he remaining 25% f rom t he hepat ic art ery (148). In c ont radist inc t ion, hepat ic neoplasms rec eiv e t heir blood supply primarily f rom t he hepat ic art ery w it h relat iv ely lit t le supply f rom t he port al v ein (510). During t he hepat ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1797

12 - Liver art erial phase of enhanc ement , solid hepat ic neoplasms are maximally enhanc ed, w hereas t he hepat ic parenc hy ma is only minimally enhanc ed bec ause subst ant ial ext rav asc ular redist ribut ion of P.838 enhanc ed port al v enous blood has not y et oc c urred. T heref ore, during t he hepat ic art erial phase “ hy perv asc ular” t umors appear as hy perat t enuat ing masses (F ig. 12- 6). “ Hy pov asc ular” t umors may be indisc ernible during t he hepat ic art erial phase, but t hey c an be demonst rat ed during t he port al v enous phase of enhanc ement as hy poat t enuat ing masses w hen subst ant ial amount s of c ont rast mat erial hav e dif f used int o t he

ext rav asc ular spac e of t he hepat ic parenc hy ma v ia t he port al v enous sy st em. In c ont radist inc t ion, hy perv asc ular t umors may bec ome indisc ernible during t he port al v enous phase if t heir int erst it ial ac c umulat ion of c ont rast mat erial is similar t o t hat of t he normal hepat ic parenc hy ma (see F ig. 12- 6).

F igure 12- 6 F oc al nodular hy perplasia. CT image ac quired during t he art erial phase of hepat ic c ont rast enhanc ement (A) demonst rat es a small subc apsular enhanc ing mass (ar r ow ). During t he port al v enous phase of enhanc ement (B) t he lesion is isoat t enuat ing and c an no longer be ident if ied.

T he t iming of peak hepat ic art erial and hepat ic parenc hy mal c ont rast enhanc ement depends primarily on t he injec t ion durat ion (102,274). Rapid or low - v olume (short er durat ion) injec t ions produc e earlier peak hepat ic enhanc ement , w hereas slow or high- v olume (longer durat ion) injec t ions result in lat er peak hepat ic enhanc ement (102,274). In pat ient s w it h normal c ardiac out put , peak art erial enhanc ement is ac hiev ed w it hin 10 sec onds af t er t he t erminat ion of t he c ont rast medium injec t ion (25), and peak hepat ic parenc hy mal enhanc ement is ac hiev ed approximat ely 30 sec onds af t er

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1798

12 - Liver

t erminat ion of t he injec t ion. As not ed earlier, diminished c ardiac out put delay s t he peaks of aort ic and hepat ic enhanc ement w it hout signif ic ant ly alt ering t he magnit ude of hepat ic enhanc ement (22).

Timing Modifications for Multidetector Computed Tomography Scanners Mult idet ec t or- row CT sc anners c an image t he liv er w it h v ery short ac quisit ion t imes c ompared w it h single det ec t or- row sc anners. T he short er MDCT sc an durat ions require a longer delay f rom t he st art of t he c ont rast medium injec t ion t o t he st art of dat a ac quisit ion in order t o image during t he peak of hepat ic parenc hy mal enhanc ement (271). T hus f or rout ine hepat ic sc reening CT examinat ions, it is nec essary t o inc rease t he sc an delay by approximat ely 5 sec onds w hen sw it c hing f rom a single det ec t or- row sc anner t o a 4 det ec t orrow sc anner, f rom a 4- row t o a 16- row sc anner, and f rom a 16- row t o a 64row sc anner. T he exac t sc an t iming w ill depend on t he injec t ion durat ion of t he c ont rast administ rat ion prot oc ol. F or example, if t he sc an delay f or a st udy on a single det ec t or- row sc anner perf ormed w it h a part ic ular c ont rast administ rat ion prot oc ol is 60 sec onds, t hen t he appropriat e sc an delay f or t he same st udy perf ormed w it h t he same injec t ion prot oc ol on a 4- row sc anner w ould be 65 sec onds; f or a 16- row sc anner, 70 sec onds; and f or a 64- row sc anner, 75 sec onds.

IMAGING TECHNIQUES Computed Tomography Without Contrast Medium Administration CT sc ans of t he liv er w it hout c ont rast medium administ rat ion are not rout inely obt ained but may be usef ul in selec t ed sit uat ions. T hese inc lude ident if ic at ion of c alc if ic at ions, hemorrhage and iron deposit ion and det erminat ion of t he prec ont rast at t enuat ion v alue of a lesion, w hic h may be helpf ul in it s c harac t erizat ion. In addit ion, primary hepat ic neoplasms or hy perv asc ular met ast ases suc h as t hose f rom c arc inoid t umor, islet c ell neoplasms, renal c ell c arc inoma, breast c arc inoma, and sarc omas may bec ome isoat t enuat ing or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1799

12 - Liver

nearly isoat t enuat ing on c ont rast - enhanc ed images (77,169) and may be more easily ident if ied on unenhanc ed images. Alt hough one st udy has show n t hat t he presenc e or absenc e of hy perv asc ular hepat ic t umors w as c orrec t ly demonst rat ed on port al v enous phase bolus P.839 dy namic c ont rast - enhanc ed CT alone in 100 of 101 pat ient s (630), it is c lear f rom st udies using dual- phase helic al CT t hat v asc ular hepat ic masses c an be missed if only port al v enous phase images are obt ained (33,57,283).

Single-Phase Contrast-Enhanced Computed Tomography T he CT t ec hnique t hat has been show n t o be t he most ef f ec t iv e f or rout ine depic t ion of liv er abnormalit ies, inc luding f oc al lesions, is dy namic bolus c ont rast - enhanc ed CT w it h imaging during t he peak of hepat ic parenc hy mal enhanc ement (port al v enous phase). T he prec ise prot oc ol depends on sev eral f ac t ors, t he most import ant of w hic h are t he t y pe of CT sc anner being used and t he pat ient 's w eight . Bec ause t he magnit ude of hepat ic enhanc ement f or a giv en dose of IV c ont rast medium is inv ersely proport ional t o pat ient w eight (275,398), t he dose should be adjust ed ac c ordingly (275). In our prac t ic e, f or st andard abdominal imaging, pat ient s w eighing up t o 250 pounds rec eiv e 125 mL of a 350 mg I/mL c ont rast agent (43.75 g I). Pat ient s w eighing more t han 250 pounds rec eiv e 150 mL (52.5 g I). Injec t ion of 20 t o 50 mL of saline immediat ely af t er c ont rast medium injec t ion (“ saline f lush” ) allow s reduc t ion in c ont rast medium v olume of 10% t o 20% (166,715). F or st andard single- phase helic al CT examinat ions of t he liv er, a c ont rast medium injec t ion rat e of 3 mL per sec ond is adequat e, as more rapid injec t ion rat es do not prov ide inc reased hepat ic parenc hy mal enhanc ement (24). As not ed earlier, t he opt imal sc an delay f or liv er imaging depends on t he c ont rast injec t ion prot oc ol (spec if ic ally , t he injec t ion durat ion) and t he t y pe of helic al CT sc anner being used. Semiaut omat ed bolus- t rac king sof t w are programs hav e prov ed usef ul f or indiv idualizing t he sc an delay f or hepat ic helic al CT examinat ion (396,740).

Multiphase Hepatic Computed Tomography

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1800

12 - Liver Mult iphase hepat ic imaging is usef ul f or t he f ollow ing indic at ions: (a)

det ec t ion of hy perv asc ular liv er lesions (33,57,121,283,298,358,531,613), (b) c harac t erizat ion of a liv er lesion det ec t ed on anot her imaging st udy suc h as ult rasound or rout ine abdominal CT (825,826) and (c ) preoperat iv e planning in a pat ient w ho is being c onsidered f or hepat ic resec t ion (f or neoplasm or liv ing relat ed donor t ransplant ) or f or int ra- art erial c hemot herapy inf usion pump plac ement . Mult iphase hepat ic prot oc ols are best perf ormed on MDCT sc anners bec ause of t heir short image ac quisit ion t imes and exc ellent spat ial resolut ion. T he c ont rast enhanc ement phases during w hic h images are obt ained depend on t he purpose of t he examinat ion. F or example, st udies t hat require det ailed depic t ion of t he hepat ic art erial anat omy , suc h as t hose of liv er resec t ion (825,826) and int ra- art erial c hemot herapy pump c andidat es (362,704), inc lude image ac quisit ion during t he early art erial phase (approximat ely 25 sec onds af t er t he st art of t he c ont rast bolus). St udies perf ormed t o det ec t or c harac t erize v asc ular liv er lesions f oc us on t he lat e hepat ic art erial phase (approximat ely 35 t o 40 sec onds af t er t he st art of t he c ont rast bolus, depending on t he t y pe of MDCT sc anner being used) w hen hy perv asc ular liv er lesions are most c onspic uous (211). MDCT sc anners are c apable of ac quiring images during bot h t he early and lat e hepat ic art erial phases in t he same examinat ion (211). In addit ion t o hepat ic art erial phase images, most mult iphase hepat ic prot oc ols also inc lude image ac quisit ion prior t o c ont rast medium administ rat ion and during t he port al v enous (hepat ic parenc hy mal) phase of enhanc ement . When imaging hepat ic resec t ion c andidat es, t he port al v enous phase images should be obt ained w it h a delay t hat is adequat e t o v isualize t he hepat ic v eins. Eac h mult iphase liv er imaging st udy should be t ailored t o ac quire images t hat sat isf y t he purpose of t he st udy . A t y pic al dual- phase post c ont rast hepat ic CT prot oc ol c onsist s of injec t ion of 150 mL of IV c ont rast mat erial at 5 mL per sec ond, w it h t he f irst phase of sc anning beginning 30 t o 40 sec onds af t er t he st art of t he bolus (depending on t he t y pe of CT sc anner) and t he sec ond phase beginning 60 t o 75 sec onds af t er t he st art of t he bolus. T he rapid injec t ion rat e maximizes bot h hepat ic art erial enhanc ement and separat ion of t he art erial and port al- v enous phases of hepat ic parenc hy mal enhanc ement (24,333,384). T he sc an delay f or art erial phase imaging c an be t imed more prec isely w it h a t est bolus or w it h bolus t rac king sof t w are. Wit h bolus t rac king sof t w are, c ont rast arriv al w it hin t he abdominal aort a (using a t hreshold v alue of 50 t o 100 HU of enhanc ement ) c an be used t o t rigger t he diagnost ic sc ans. F or early art erial phase imaging (t o

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1801

12 - Liver demonst rat e art erial anat omy ), image ac quisit ion should be t riggered at t he t ime of c ont rast arriv al. F or lat e art erial phase imaging (t o demonst rat e hy perv asc ular liv er lesions), an addit ional delay is needed bef ore image

ac quisit ion begins (15 sec onds f or 4 det ec t or- row sc anners; 20 sec onds f or 16 and 64 det ec t or- row sc anners).

Angiography-Assisted Computed Tomography Hepat ic CT t hat uses c ont rast mat erial administ ered t hrough an art erial c at het er is a sensit iv e t ec hnique f or det ec t ing liv er lesions (216,273,381,506,507,574). CT hepat ic ar t er iogr aphy (CT HA) is perf ormed w it h t he c at het er in t he hepat ic art ery or c eliac axis (112,216,307). On CT images obt ained w it h t his t ec hnique, malignant hepat ic neoplasms appear as peripherally or homogeneously enhanc ing hy perdense masses c ompared w it h t he normal hepat ic parenc hy ma (112,216,307). A pot ent ial pit f all of t his met hod is t hat homogeneous enhanc ement of t he normal hepat ic parenc hy ma is obt ained in only about t w o t hirds of pat ient s due t o a v ariet y of c auses, inc luding replac ed hepat ic art eries and alt ered hepat ic hemody namic s (218). Hepat oc ellular c arc inomas imaged w it h t his t ec hnique appear larger t han t heir t rue size due t o enhanc ement of t he immediat ely adjac ent hepat ic P.840 parenc hy ma (“ c orona enhanc ement ” ) (512). CT ar t er ial por t ogr aphy (CT AP) is perf ormed during inf usion of c ont rast mat erial t hrough a c at het er in t he superior mesent eric (SMA) or splenic art ery (56,249). On CT AP images, hepat ic neoplasms appear as hy poat t enuat ing masses bec ause t hey rec eiv e predominant ly art erial supply , w hereas t he normal hepat ic parenc hy ma is supplied predominant ly by t he port al v enous sy st em. CT AP is a highly sensit iv e t ec hnique f or det ec t ing liv er lesions (273,506,507,574) but has a high f alse posit iv e rat e due t o v arious t y pes of perf usion abnormalit ies (156,200,477,511,577,637,756,823). Prior t o t he av ailabilit y of MDCT and c urrent st at e- of - t he- art 3D MR imaging t ec hniques, CT AP w as t he most ef f ec t iv e imaging t ec hnique f or t he pre- operat iv e det erminat ion of hepat ic t umor resec t abilit y (421,575,747,753). How ev er, mult iphase MDCT , gadoliniumc helat e- enhanc ed 3D int erpolat ed breat h- hold MRI, and superparamagnet ic iron–oxide enhanc ed MRI hav e largely replac ed CT HA and CT AP f or preoperat iv e ev aluat ion of pat ient s w it h pot ent ially resec t able primary and sec ondary liv er lesions (336,394,722,726). CT HA may be used prior t o c hemoembolizat ion of hepat oc ellular c arc inomas.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1802

12 - Liver

Computed Tomography After Injection of Iodized Oil CT perf ormed 1 t o 4 w eeks af t er hepat ic art ery injec t ion of iodized oil (e.g., Lipiodol) has been used t o det ec t small hepat oc ellular c arc inomas (568,597,908). T he iodized oil is rapidly c leared f rom t he normal hepat ic parenc hy ma by t he ret ic uloendot helial sy st em but is ret ained in v asc ular hepat ic neoplasms. T umors t hat ret ain t he oil appear as hy perat t enuat ing masses. T he t ec hnique has demonst rat ed small hepat oc ellular c arc inomas not det ec t ed by ot her imaging t ec hniques (568,908) but has not been suc c essf ul in demonst rat ing some hy pov asc ular hepat oc ellular c arc inomas (899).

Magnetic Resonance Imaging Despit e t he f ac t t hat MRI has been show n t o be equiv alent or superior t o CT f or many hepat ic imaging t asks, it c ont inues t o play a more limit ed role t han CT in liv er ev aluat ion. Reasons f or t he limit ed use of hepat ic MRI inc lude c ost , av ailabilit y , lengt h of examinat ion, and limit ed ev aluat ion of pulmonary and ext rahepat ic abdominal disease. At many inst it ut ions MRI serv es primarily as a problem- solv ing t ec hnique and is used only in selec t ed c linic al sit uat ions. Nev ert heless, MRI play s an import ant role in ev aluat ing t he liv er in some pat ient s. MRI c an be used as t he primary imaging examinat ion f or pat ient s w ho c annot rec eiv e iodinat ed IV c ont rast mat erial and pat ient s in w hom t he liv er is t he only organ of c onc ern. Magnet ic resonanc e imaging is c apable of prov iding a more def init iv e diagnosis of hepat ic iron deposit ion in pat ient s in w hom iron ov erload is a c linic al c onc ern. In addit ion, MRI is superior t o CT f or ev aluat ing pat ient s w it h c irrhosis. MRI is usef ul as a problem- solv ing t ec hnique w hen ot her imaging st udies hav e raised t he quest ion of f oc al st eat osis v ersus neoplasm or small hepat ic hemangioma v ersus malignant neoplasm. In addit ion, MRI is usef ul in ev aluat ing c anc er pat ient s w it h dif f use or geographic hepat ic st eat osis w hen a CT examinat ion has f ailed t o demonst rat e f oc al lesions.

Magnetic Resonance Imaging Without Contrast Medium Administration

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1803

12 - Liver An MRI examinat ion of t he liv er inc ludes bot h T 1- and T 2- w eight ed pulse

sequenc es. T 1- w eight ed sequenc es are usef ul f or lesion det ec t ion and prov ide bet t er anat omic det ail t han T 2- w eight ed sequenc es due t o t heir higher signalt o- noise rat io. T 1- w eight ed sequenc es may be obt ained w it h eit her spin- ec ho or gradient ec ho t ec hniques, but breat h- hold gradient ec ho t ec hniques hav e largely replac ed spin ec ho imaging. T o ac hiev e adequat e T 1 w eight ing w it h spin ec ho imaging, a repet it ion t ime (T R) less t han 300 msec and ec ho t ime (T E) less t han 15 msec should be used. Mult iple signal ac quisit ions (signal av eraging) (772,878) and respirat ory - ordered phase enc oding (27) c an be used t o dec rease mot ion art if ac t s w hen spin- ec ho imaging is used. Wit h spoiled gradient ec ho pulse sequenc es, t he ent ire liv er c an be imaged in one or t w o breat h holds, t hus eliminat ing respirat ory mot ion art if ac t s (179,870). By v ary ing t he T E of T 1- w eight ed gradient ec ho sequenc es, inphase and out - of - phase (opposed- phase) images, w hic h prov ide inf ormat ion on parenc hy mal and lesion f at c ont ent , c an be obt ained (536,538). If images are obt ained w hen t he f at and w at er prot ons are in- phase, t heir signals are addit iv e; c onv ersely , if images are obt ained w hen t he f at and w at er prot ons are out - of - phase, net c anc ellat ion of signal in v oxels c ont aining f at and w at er result s in dec reased signal int ensit y c ompared w it h t hat of t he same v oxel on in- phase images. T hus opposed- phase gradient ec ho imaging is usef ul f or diagnosing f oc al or dif f use hepat ic st eat osis. It is import ant t o obt ain bot h inphase and opposed- phase images bec ause hepat ic masses may be obsc ured on opposed- phase images in pat ient s w it h dif f use hepat ic st eat osis (F ig. 12- 7) (682). On T 1- w eight ed images most f oc al lesions appear hy point ense c ompared w it h t he normal hepat ic parenc hy ma. Exc ept ions inc lude hemorrhagic lesions, lesions c ont aining f at (e.g., f oc al st eat osis, some hepat oc ellular c arc inomas and adenomas, lipomas, and angiomy olipomas), and some met ast ases f rom melanoma (371,430,656). T 2- w eight ed sequenc es are not only usef ul f or lesion det ec t ion but are more usef ul t hat T 1- w eight ed sequenc es f or lesion c harac t erizat ion. Alt hough T 2w eight ed images c an be obt ained using eit her c onv ent ional or ec ho t rain (f ast spin- ec ho; t urbo spin- ec ho) t ec hniques, c onv ent ional T 2- w eight ed spin ec ho imaging is now rarely used bec ause of it s long ac quisit ion t ime and assoc iat ed mot ion art if ac t s (227). Ec ho t rain t ec hniques hav e markedly reduc ed t he ac quisit ion t ime nec essary f or T 2- w eight ed imaging (98,581,618,717,751) P.841

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1804

12 - Liver

and hav e largely replac ed c onv ent ional T 2- w eight ed sequenc es. T he lengt h of t he ec ho t rain is proport ional t o t he reduc t ion in sc an t ime (548). Wit h longer ec ho t rains, T 2- w eight ed images c an be obt ained in a breat h- hold (176). Use of f at suppression or respirat ory t riggering c an improv e t he qualit y of non–breat h- hold ec ho t rain T 2- w eight ed imaging (548). On T 2- w eight ed images, most hepat ic lesions appear hy perint ense c ompared w it h normal hepat ic parenc hy ma.

F igure 12- 7 Hepat ic mass obsc ured on opposed- phase image. A: In- phase T 1- w eight ed gradient ec ho image show s a hy point ense mass (ar r ow ) in t he right lobe. B: T he mass is obsc ured on an opposed- phase image bec ause of hepat ic parenc hy mal signal loss due t o st eat osis.

Short t au inv ersion rec ov ery (ST IR) imaging c ombines T 1 and T 2 ef f ec t s w it h f at suppression t o generat e images in w hic h most pat hology and f luid appears

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1805

12 - Liver high in signal int ensit y , similar t o T 2- w eight ed imaging. Breat h- hold ST IR imaging, obt ained by c ombining ec ho t rain t ec hniques w it h inv ersion rec ov ery imaging, improv es det ec t ion of liv er lesions c ompared w it h non–breat h- hold ST IR imaging (176).

Contrast-Enhanced Magnetic Resonance Imaging T he t w o major c lasses of MR liv er c ont rast agent s are (a) nonspec if ic c ont rast media t hat dist ribut e t o t he ext rac ellular spac e and (b) liv er- spec if ic agent s t hat are t aken up by hepat oc y t es or Kupf f er c ells (714). Ext rac ellular agent s are used f or dy namic phase imaging, w hereas t he liv er- spec if ic agent s are imaged af t er a delay of minut es t o hours t o allow ac c umulat ion of t he agent w it hin liv er c ells. A t hird c lass of agent s, inc luding gadobenat e dimeglumine (Gd- BOPT A) and gadoxet at e disodium (Gd- EOB- DT PA), c ont ain bot h ext rac ellular and liv er- spec if ic propert ies. Gadolinium- c helat es, w hic h are ext rac ellular paramagnet ic c ont rast agent s t hat short en T 1 and T 2 relaxat ion (T 2* ), are t he most w idely used MR c ont rast media. T hey produc e signal enhanc ement on T 1- w eight ed images as a result of t he P.842 T 1 short ening ef f ec t t hat predominat es w it h pharmac ologic doses of t he agent (701). T he pharmac okinet ic s and biodist ribut ion of st andard Gd- c helat es are similar t o t hose of iodinat ed c ont rast agent s (74,857). T hus int rav enously administ ered Gd- c helat e rapidly dif f uses int o t he ext rav asc ular spac e. Consequent ly , Gd- enhanc ed imaging is most usef ul w hen perf ormed in c onjunc t ion w it h dy namic gradient ec ho sequenc es. Rout ine use of an MRIc ompat ible pow er injec t or prov ides reliable and reproduc ible c ont rast deliv ery . Use of a t est bolus (175) or an aut omat ed c ont rast bolus det ec t ion t ec hnique (295) t o det ermine t he appropriat e sc an delay is rec ommended. Af t er c ont rast medium administ rat ion, images are obt ained during t he lat e art erial, hepat ic parenc hy mal, and equilibrium phases. Use of a 3D v olumet ric int erpolat ed breat h- hold examinat ion af t er t est bolus- t imed dy namic c ont rast enhanc ement prov ides c onsist ent ly high- qualit y c ont rast - enhanc ed images of t he liv er w it h smaller sec t ion t hic kness (431). T here is c ont inued debat e about t he v alue of Gd- c helat e–enhanc ed MR imaging f or liv er lesion det ec t ion, despit e t he f ac t t hat sev eral st udies hav e show n inc reased det ec t ion of liv er lesions w it h gadolinium- enhanc ed MR imaging c ompared w it h unenhanc ed MRI (55,140,764). In one of t he st udies,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1806

12 - Liver unenhanc ed imaging demonst rat ed more lesions ov erall, but gadoliniumenhanc ed imaging demonst rat ed more nonc y st ic liv er lesions (140). Anot her st udy , how ev er, demonst rat ed no st at ist ic ally signif ic ant dif f erenc e bet w een unenhanc ed and gadolinium- enhanc ed MR imaging in dif f erent iat ing pat ient s w it h liv er met ast ases f rom t hose w it hout met ast ases (261). Nev ert heless,

most expert s in body MR imaging c onsider gadolinium–enhanc ement t o be an int egral part of t he MR liv er imaging examinat ion f or lesion det ec t ion, espec ially f or det ec t ion of hepat oc ellular c arc inomas in pat ient s w it h c irrhosis. F urt hermore, ot her st udies hav e demonst rat ed t he usef ulness of gadoliniumenhanc ed imaging in c harac t erizing hepat ic lesions (260,482,822,865,887,895). Superparamagnet ic iron oxide (SPIO) c ont rast agent s are t aken up selec t iv ely by t he ret ic uloendot helial sy st em and markedly short en t he T 2 relaxat ion of t he liv er, result ing in a prof ound loss of signal f rom normal liv er t issue (484,706). Bec ause upt ake of t he agent s by t umors is primarily dependent on t he presenc e of Kupf f er c ells, most hepat ic masses, most import ant ly met ast ases and moderat ely t o poorly dif f erent iat ed hepat oc ellular c arc inomas, st and out as hy perint ense f oc i in t he low - signal- int ensit y liv er (705,774). Alt hough result s hav e v aried, t he majorit y of st udies t o assess t he ef f ic ac y of t hese c ont rast agent s hav e demonst rat ed inc reased lesion- t o- liv er c ont rast (705,774,873) and inc reased t umor det ec t ion rat e (690,812,875) w it h SPIOenhanc ed imaging c ompared w it h unenhanc ed MR imaging (38,40,616,671,672,690,726,774,812,873). Result s of SPIO- enhanc ed imaging f or det ec t ion of hepat oc ellular c arc inoma hav e been v ariable. One draw bac k is t hat dec reased upt ake of iron oxide part ic les in c irrhot ic liv er parenc hy ma due t o dec reased ac t iv it y of Kuppf er c ells c an obsc ure small lesions (631). In addit ion, lac k of upt ake in f ibrot ic areas of c irrhot ic liv ers c an result in a high f alse posit iv e rat e (276). Double- c ont rast MR imaging (administ rat ion of SPIO f ollow ed by bolus gadolinium- enhanc ed imaging) inc reases t he sensit iv it y f or hepat oc ellular c arc inoma in pat ient s w it h c irrhosis, c ompared w it h SPIOenhanc ed imaging alone (850). Superparamagnet ic iron oxide also has been used t o c harac t erize liv er lesions based on t he upt ake of t he agent by f oc al nodular hy perplasia (621,645,655,672). How ev er, c aut ion must be used in int erpret ing liv er lesion signal loss w it h SPIO as a sign of a benign lesion, as early hepat oc ellular c arc inoma also has been report ed t o show signal loss af t er SPIO administ rat ion (250,798,841,882). In addit ion, ot her benign lesions suc h as hepat oc ellular adenoma, hemangioma, and regenerat iv e nodular hy perplasia may also show signal drop af t er SPIO administ rat ion (645,671).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1807

12 - Liver T he iron oxide enhanc ement of hemangiomas may be due t o pooling of t he c ont rast agent w it hin v asc ular lakes or iron phagoc y t osis by endot helial c ells (159,250). Enhanc ement of adenomas, most of w hic h do not c ont ain

signif ic ant numbers of Kuppf er c ells, may be sec ondary t o pooling of t he agent in peliosis- like dilat ed v essels (159). Mangaf odipir t risodium (Mn- DPDP) is a T 1- short ening c ont rast agent t hat is t aken up by t he hepat oc y t es and eliminat ed in t he bile (184,464,576). Clinic al t rials hav e demonst rat ed inc reased det ec t ion of hepat ic met ast ases af t er MnDPDP administ rat ion (49,194,259,699,810). In addit ion, bec ause t he agent is inc orporat ed int o some hepat ic masses (mainly primary hepat oc ellular t umors), Mn- DPDP may hav e some ut ilit y in c harac t erizing hepat ic lesions (681,840). How ev er, upt ake of Mn- DPDP oc c urs in bot h benign and malignant hepat oc ellular t umors, and it also c an be observ ed in met ast ases f rom neuroendoc rine t umors (504,846). T hus f urt her t est ing is required t o det ermine t he role of t his c ont rast agent in lesion c harac t erizat ion. Gadobenat e dimeglumine (Gd- BOPT A) and gadoxet at e (Gd- EOB- DT PA) are T 1short ening c ont rast agent s t hat are f irst dist ribut ed in t he ext rac ellular spac e like st andard ext rac ellular c ont rast agent s. How ev er, t hese agent s undergo bot h glomerular f ilt rat ion and selec t iv e upt ake int o hepat oc y t es, w it h subsequent biliary exc ret ion. Clinic al t rials hav e demonst rat ed inc reased det ec t ion of hepat ic lesions af t er administ rat ion of t hese c ont rast agent s (262,293,413,635). In addit ion, bec ause t he agent s are inc orporat ed int o primary hepat oc ellular t umors, t hey may be usef ul in c harac t erizing hepat ic lesions (253,254,294,486,635).

BENIGN HEPATIC TUMORS Cysts Developmental (Simple) Cysts Simple hepat ic c y st s are c ommon lesions, oc c urring in 5% t o 14% of t he general populat ion (141), more of t en in w omen (828). T hey may be solit ary or mult iple. Hepat ic P.843 c y st s are t hought t o arise f rom bile duc t epit helium and are lined by a single lay er of c uboidal or, less c ommonly , squamous or c olumnar epit helium (141).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1808

12 - Liver T he CT appearanc e of hepat ic c y st is t hat of a w ell- c irc umsc ribed, homogeneous mass of near- w at er- at t enuat ion v alue (less t han 20 HU), w hic h show s no enhanc ement af t er IV c ont rast medium administ rat ion (562) (F ig. 12- 8). Small lesions may appear t o hav e a densit y higher t han 20 HU bec ause of part ial v olume av eraging w it h adjac ent hepat ic parenc hy ma, espec ially on c ont rast - enhanc ed images. If t hin sec t ion CT does not allow a def init iv e diagnosis, ult rasound usually is helpf ul in demonst rat ing t he c y st ic nat ure of t he mass (195). On MRI examinat ions, simple c y st s are w ell- def ined, homogeneous lesions t hat are hy point ense on T 1- w eight ed images and markedly hy perint ense on heav ily T 2- w eight ed images (876) (F ig. 12- 9). T he appearanc e of a c y st may be indist inguishable f rom t hat of a hepat ic

hemangioma on bot h T 1- and T 2- w eight ed images. How ev er, t hese t w o lesions c an be dist inguished on Gd- enhanc ed imaging as hemangiomas undergo a t y pic al enhanc ement pat t ern, w hereas c y st s do not enhanc e (see F ig. 12- 9).

F igure 12- 8 Hepat ic c y st s. Cont rast - enhanc ed CT show s t w o large w ellc irc umsc ribed, homogeneous, near- w at er- densit y masses t hat hav e no disc ernible w all.

Ot her c y st ic masses, inc luding int rahepat ic biloma or pseudoc y st , hy dat id c y st , absc ess, and c y st ic neoplasm, may hav e an appearanc e similar t o t hat of simple hepat ic c y st . How ev er, t hese lesions are usually dist inguishable f rom simple c y st by v irt ue of f eat ures suc h as a t hic k or irregular w all, int ernal sept at ions, or a densit y great er t han 20 HU. Oc c asionally , a hepat ic c y st may bec ome c omplic at ed by hemorrhage or inf ec t ion, in w hic h c ase it may be indist inguishable f rom t hese ot her c y st ic lesions (31).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1809

12 - Liver

F igure 12- 9 Aut osomal dominant poly c y st ic kidney and liv er disease. Coronal T 2- w eight ed MR image (A) show s numerous hy perint ense c y st s of v arious sizes sc at t ered t hroughout t he liv er and bot h kidney s. T ransaxial gadoliniumenhanc ed T 1- w eight ed image (B) show s no enhanc ement of t he c y st s.

Polycystic Liver Disease Mult iple hepat ic c y st s oc c ur c ommonly in pat ient s w it h aut osomal- dominant poly c y st ic kidney disease (449). T he c y st s may v ary c onsiderably in size and may c ause marked enlargement of t he liv er (see F ig. 12- 9). T here is no c orrelat ion bet w een t he sev erit y of liv er inv olv ement and t he ext ent of renal c y st ic disease (449). T he c y st s are t hought t o result f rom progressiv e dilat ion of t he abnormal duc t s in biliary hamart omas as part of a duc t al plat e malf ormat ion inv olv ing t he small int rahepat ic bile duc t s (72). T hey are more prev alent and prominent in w omen (189). T he c y st s are rarely observ ed prior t o pubert y , begin t o dev elop w it h t he onset of pubert y , and inc rease dramat ic ally in size and P.844 number t hrough t he c hildbearing y ears (189). Pat ient s w it h small or sparse c y st s are usually asy mpt omat ic , but t hose w ho dev elop massiv e hepat ic c y st ic disease may bec ome sy mpt omat ic w it h abdominal pain, early post prandial f ullness, or short ness of breat h (189). Liv er f unc t ion t est s in pat ient s w it h poly c y st ic liv er disease are generally normal (449). As w it h any ot her c y st s, t he hepat ic c y st s in t hese pat ient s may oc c asionally be c omplic at ed by hemorrhage or inf ec t ion (449,867). On CT , hemorrhage int o a hepat ic c y st result s in an at t enuat ion v alue great er t han 20 HU. On MRI t his c omplic at ion c auses inc reased signal int ensit y of t he c y st due t o t he T 1- short ening ef f ec t

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1810

12 - Liver

of met hemoglobin (867). MRI is somew hat more sensit iv e t han CT in ident if y ing c omplic at ed hepat ic c y st s (552).

Biliary Hamartomas Biliary hamart omas, also know n as v on Mey enburg c omplexes, c onsist of dilat ed bile duc t st ruc t ures lined by biliary epit helium and ac c ompanied by a v ariable amount of f ibrous st roma (72). T hey are t hought t o arise f rom embry onic bile duc t s t hat f ail t o inv olut e (552). On CT t hey appear as small (usually less t han 1.5 c m in diamet er) hy poat t enuat ing, c y st - like st ruc t ures t hat show lit t le or no enhanc ement af t er int rav enous c ont rast medium administ rat ion (F ig. 12- 10). T hey c an be solit ary but t y pic ally are mult iple and sc at t ered t hroughout t he liv er (451,480,550,746). T he MRI appearanc e is t hat of mult iple small lesions t hat are hy point ense on T 1- w eight ed images and markedly hy perint ense on T 2- w eight ed images (F ig. 12- 11). Most do not enhanc e af t er gadolinium- c helat e administ rat ion, but some lesions may demonst rat e eit her int ernal enhanc ement (480,877) or rim enhanc ement , w hic h represent s c ompressed hepat ic parenc hy ma surrounding t he lesion (552,723).

F igure 12- 10 Biliary hemart omas. Cont rast - enhanc ed CT show s mult iple small low at t enuat ion lesions sc at t ered t hroughout t he liv er. Court esy of Mic hael Pay ne, MD.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1811

12 - Liver

F igure 12- 11 Biliary hamart omas in t w o pat ient s. T ransaxial (A) and c oronal (B) half - F ourier single shot t urbo spin ec ho (HAST E) MR images show mult iple small hy perint ense lesions sc at t ered t hroughout t he liv er in eac h pat ient .

Biliary hamart omas do not c ause sy mpt oms and usually are disc ov ered inc ident ally . T hey may be dif f ic ult t o dist inguish f rom hepat ic c y st s or mic roabsc esses (289). P.845 How ev er, a more import ant c linic al dist inc t ion is bet w een biliary hamart omas and hepat ic met ast ases, f or w hic h t hey are f requent ly mist aken. Biliary hamart omas usually c an be dist inguished f rom met ast ases by t heir relat iv ely small and unif orm size and t heir v ery st rong signal int ensit y on T 2- w eight ed images.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1812

12 - Liver F igure 12- 12 Peribiliary c y st s. Cont rast - enhanc ed CT (A) and c orresponding port al- v enous phase gadolinium- enhanc ed T 1- w eight ed spoiled gradient ec ho MR image (B) show numerous c y st s paralleling t he c ent ral bile duc t s in a pat ient w it h c irrhosis. Not e t hat t he c y st s are loc at ed on bot h sides of t he int rahepat ic port al v ein branc hes and c ause irregular narrow ing of t he port al v eins.

Peribiliary Cysts Peribiliary c y st s result f rom c y st ic dilat ion of obst ruc t ed periduc t al glands (32,322). T hey oc c ur adjac ent t o large int rahepat ic and ext rahepat ic bile duc t s and are usually asy mpt omat ic (32,322). Peribiliary c y st s oc c ur signif ic ant ly more c ommonly in pat ient s w it h c irrhosis t han in t hose w it hout c irrhosis (32,290,322,805). On CT examinat ions t he lesions appear as eit her disc ret e c y st ic st ruc t ures or as low - densit y t ubular st ruc t ures paralleling t he c ent ral port al v eins (F ig. 12- 12) (32,290,322,805). Wit h MRI t he lesions are best seen on T 2- w eight ed or gadolinium- enhanc ed T 1- w eight ed gradient ec ho images as c y st ic or t ubular periport al st ruc t ures t hat may simulat e dilat ed bile duc t s (F igs. 12- 12 and 12- 13) (32,805).

Hemangioma Hepat ic hemangioma is t he most c ommon benign liv er t umor, oc c urring in up t o 7% of t he normal adult populat ion, alt hough one prospec t iv e st udy ident if ied hemangiomas in 20% of liv er aut opsy spec imens (363). Pat hologic ally , hemangiomas c onsist of int erc onnec t ed endot helial- lined v asc ular c hannels, enc losed w it hin a loose f ibroblast ic st roma (880). T hey are f ed by hepat ic art ery branc hes, and t heir int ernal c irc ulat ion is slow . T hey generally remain st able in size ov er t ime but may oc c asionally demonst rat e grow t h (233,558,584,794). On CT , hemangiomas are sharply def ined masses t hat are usually hy poat t enuat ing c ompared w it h t he adjac ent hepat ic parenc hy ma on unenhanc ed images. How ev er, t hey may be iso- or hy perat t enuat ing in pat ient s w it h hepat ic st eat osis. On unenhanc ed images t he v asc ular c omponent s of hemangiomas hav e t he same at t enuat ion v alue as t he blood w it hin blood v essels (777,864) (F ig. 12- 14A). T hrombosed, f ibrot ic , or degenerat ed areas t hat are f requent ly present w it hin large hemangiomas are low er in at t enuat ion t han t he v asc ular c omponent s (F ig. 12- 15). Hemangiomas

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1813

12 - Liver

hav e a dist inc t iv e pat t ern of enhanc ement af t er administ rat ion of int rav enous c ont rast medium, c harac t erized by sequent ial c ont rast opac if ic at ion usually beginning at t he periphery of t he lesion as one or more nodular or globular areas of enhanc ement , and proc eeding t ow ard t he c ent er (17,217,312,445,659,777) (see F igs. 12- 14 and 12- 15). F ibrot ic areas w it hin t he lesion do not bec ome opac if ied. T he f eat ure of globular enhanc ement (F ig. 12- 16) w as f ound in one st udy t o be 88% sensit iv e and 84% t o 100% spec if ic f or dif f erent iat ing hepat ic hemangiomas f rom hy perv asc ular met ast ases on single- pass, c ont rast - enhanc ed CT (444). In anot her st udy , 94% of hepat ic lesions demonst rat ing f oc i of globular enhanc ement w ere hemangiomas (659). T he t ime required f or c omplet e c ont rast “ f ill- in” of a hemangioma depends on it s size. Small lesions may bec ome c omplet ely opac if ied in less t han 1 minut e and appear homogeneously high at t enuat ion on art erial or port al v enous phase images (F ig. 12- 17), w hereas large lesions may require 20 minut es or more f or c omplet e opac if ic at ion (see F ig. 12- 15). Small rapidly enhanc ing hemangiomas may be assoc iat ed w it h adjac ent hepat ic parenc hy mal enhanc ement (“ st aining” ) relat ed t o art erioport al shunt s (see F ig. 1217) (265). T he int ensit y of c ont rast opac if ic at ion t hat oc c urs w it hin t he v asc ular spac es of a hemangioma depends on P.846 t he c onc ent rat ion of iodine in t he bloodst ream. On any giv en image, t he densit y of t he enhanc ed v asc ular spac es approximat es t he densit y of t he normal v asc ular st ruc t ures on t he same image (226,444,777) (see F igs. 12- 14, 12- 15, and 12- 17). Alt hough some solid v asc ular hepat ic neoplasms may show dense c ont rast enhanc ement during t he early phase of t he c ont rast bolus, t he densit y of t hese lesions f ades more rapidly t han t he densit y of normal v essels. Anot her sign t hat c an be helpf ul in dif f erent iat ing a malignant lesion f rom a hemangioma is a rim- like zone of hy poat t enuat ion at t he periphery of t he mass. Suc h a hy poat t enuat ing rim is indic at iv e of a malignant neoplasm and is not seen w it h hemangiomas. Angiosarc oma is an exc eedingly rare malignant liv er t umor, w hic h may hav e an enhanc ement pat t ern similar t o t hat of hemangioma, but w hic h usually c an be dist inguished f rom hemangioma on mult iphase helic al CT examinat ions (see t he sec t ion Rare Malignant T umors) (401,639).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1814

12 - Liver

F igure 12- 13 Peribiliary c y st s. T ransaxial (A) and c oronal (B) T 2- w eight ed and t ransaxial gadolinium- enhanc ed T 1- w eight ed (C ) MR images show innumerable c y st s of v ary ing sizes lined up along t he bile duc t s. T he appearanc e c ould be mist aken f or a dif f usely dilat ed biliary sy st em. Endosc opic ret rograde c holangiogram image (D) demonst rat es mult iple smoot h rounded areas of ext ernal c ompression c ausing narrow ing of t he bile duc t s w it h areas of peripheral dilat ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1815

12 - Liver

F igure 12- 14 Hemangioma. A: Prec ont rast CT image demonst rat es a small mass (ar r ow head) w it h an at t enuat ion v alue similar t o t hat of t he blood in t he inf erior v ena c av a (C). B: Art erial phase image. T he mass show s mult iple areas of globular, peripheral enhanc ement . Not e t hat t he enhanc ed port ions of t he mass hav e an at t enuat ion v alue similar t o t hat of t he int rahepat ic v essels. C : Equilibrium phase image show s near- c omplet e enhanc ement of t he mass w it h an at t enuat ion v alue equiv alent t o t hat of t he blood in t he inf erior v ena c av a and hepat ic v eins.

P.847 MRI has been show n t o be usef ul in dist inguishing hemangiomas f rom malignant hepat ic neoplasms based on t he v ery long T 2 relaxat ion of hemangioma c ompared w it h ot her hepat ic masses (521,598,600,769). Consequent ly , hemangiomas appear higher in signal int ensit y on T 2- w eight ed images t han ot her hepat ic neoplasms (F ig. 12- 18). Ot her f eat ures c harac t erist ic but not diagnost ic of hemangioma inc lude a sharp margin and int ernal homogeneit y (116,237,315,472,769). Hemangiomas great er t han 4 c m in diamet er, how ev er, are f requent ly het erogeneous in signal int ensit y , ow ing t o v arious c ombinat ions of f ibrosis, hemorrhage, t hrombosis, hy alinizat ion, and c y st ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1816

12 - Liver

degenerat ion (114,688). Using non–c ont rast - enhanc ed MRI and quant it at iv e c harac t erist ic s alone (i.e., T 2 v alues or lesion- t o- liv er signal int ensit y rat ios), hemangiomas c an be dist inguished f rom malignant hepat ic masses w it h an ac c urac y of 81% t o 97% (315,521,534,598,600,601,769). When morphologic c harac t erist ic s are also c onsidered, t his dif f erent iat ion has been made in 90% t o 94% of c ases (53,534,769). A helpf ul c harac t erist ic of hemangioma is t hat it demonst rat es a relat iv e inc rease in signal int ensit y on heav ily T 2- w eight ed MR images c ompared w it h moderat ely T 2- w eight ed images. In c ont radist inc t ion, ot her hepat ic masses exc ept f or c y st s show a relat iv e dec rease in signal int ensit y on more heav ily T 2- w eight ed images. How ev er, on non–c ont rast - enhanc ed MRI, v asc ular met ast ases suc h as t hose f rom pheoc hromoc y t oma, c arc inoid, and panc reat ic islet c ell t umors are oc c asionally indist inguishable f rom hemangioma bec ause of t heir marked hy perint ensit y on T 2- w eight ed images (456,695). Dy namic gadoliniumenhanc ed MRI is helpf ul in making t his dif f erent iat ion (42,539,763,865) (see F ig. 12- 18). Hemangiomas t y pic ally show early hy perint ense peripheral nodular enhanc ement w it h c omplet e f ill- in on delay ed images. How ev er, small lesions may show early unif orm enhanc ement , w hereas some lesions, part ic ularly large ones, may demonst rat e persist ent c ent ral hy point ensit y due t o areas of f ibrosis, t hrombosis, or degenerat ion. Prolonged c ont rast mat erial ret ent ion w it h signal int ensit y similar t o t he blood pool on 10- t o 15- minut e delay ed images is c harac t erist ic of hemangioma. At hough most small (less t han 2 c m in diamet er) hemangiomas demonst rat e t y pic al enhanc ement , some show P.848 an at y pic al pat t ern c harac t erized by persist ent low at t enuat ion during bot h t he hepat ic art erial and port al v enous phases of enhanc ement . T he f inding w it hin t hese lesions of a small bright dot t hat does not progress t o a f oc us of globular enhanc ement (“ bright dot ” sign) c an be helpf ul in suggest ing t he diagnosis (335).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1817

12 - Liver

F igure 12- 15 Giant hemangioma. Art erial (A) and port al v enous phase (B) CT images show a large mass replac ing most of t he right hepat ic lobe. T he c harac t erist ic areas of peripheral nodular enhanc ement are larger and ext end more c ent rally on t he port al v enous phase image. Not e t hat t he at t enuat ion of t he enhanc ed port ions of t he mass is similar t o t hat of t he enhanc ed blood v essels. T he ext ent of t he mass is w ell demonst rat ed on t he 3D v olume rendered image (C ). T he irregular c ent ral area of low er at t enuat ion (ar r ow heads) is an area of c ent ral f ibrosis.

Unc ommonly , hemangiomas may demonst rat e ot her at y pic al f eat ures inc luding hemorrhage (837), c alc if ic at ion (540,710,837), c apsular ret rac t ion (65,837), and hy alinizat ion (110,792,815,837). Hy alinizat ion of a hemangioma alt ers it s imaging f eat ures, making diagnosis v ery dif f ic ult . On T 2- w eight ed MR images a hy alinized hemangioma is only mildly hy perint ense (110). On c ont rast enhanc ed CT or MRI it t y pic ally show s no early enhanc ement w it h only slight peripheral enhanc ement on delay ed images (F ig. 12- 19) (110).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1818

12 - Liver

F igure 12- 16 Hemangiomas. An art erial phase maximum int ensit y projec t ion (MIP) image demonst rat es t he hepat ic art erial supply (ar r ow heads) of t w o small hemangiomas in t he right lobe. Not e t he t y pic al peripheral nodular enhanc ement of t he lesions.

T he approac h t o diagnosing hepat ic hemangioma in any giv en pat ient depends on sev eral f ac t ors, inc luding t he c linic al hist ory , t he pref erenc es of t he pat ient and ref erring P.849 phy sic ian, and t he imaging t ec hniques av ailable. In general, t he f ollow ing approac h is rec ommended. Lesions disc ov ered inc ident ally on ult rasound (437) or CT t hat are solit ary and t y pic al of hemangioma c an be c onsidered benign and ignored if t he pat ient has no know n or suspec t ed primary malignanc y . How ev er, if t he ult rasound or CT f indings are at y pic al, or t he pat ient has a know n or suspec t ed primary malignanc y , an addit ional imaging t est , eit her t ec hnet ium- 99m pert ec hnet at e labeled red blood c ell (RBC) sc int igraphy or MRI, c an prov ide a more def ini- t iv e diagnosis. T ec hnet ium- 99m pert ec hnet at elabeled RBC sc int igraphy using single phot on emission CT (SPECT ) is usef ul if t he lesion in quest ion is equal t o or great er t han 2 c m in diamet er (53,409,814). T he demonst rat ion on suc h st udies of a def ec t on early sc ans w it h prolonged and persist ent radiot rac er upt ake on delay ed sc ans is v irt ually diagnost ic of hemangioma (409,814). F or lesions less t han 2 c m in diamet er and t hose less t han 2.5 c m t hat are loc at ed adjac ent t o t he heart or major int rahepat ic v essels, MRI is t he pref erred imaging t est , as it is more sensit iv e t han labeled RBC P.850

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1819

12 - Liver SPECT sc anning f or suc h lesions (53). An adv ant age of MRI c ompared w it h

labeled RBC imaging is t hat c ont rast - enhanc ed MRI is c apable of est ablishing a diagnosis, ev en if t he lesion is not a hemangioma. Only rarely is a biopsy nec essary t o diagnose hepat ic hemangioma.

F igure 12- 17 Hemangioma w it h art erioport al shunt ing. Art erial phase CT image (A) show s a small, round rapidly enhanc ing mass (ar r ow ) w it h at t enuat ion similar t o t hat of t he aort a. A slight ly more c audal image (B) demonst rat es a w edge- shaped area of parenc hy mal enhanc ement adjac ent t o t he mass c aused by art erioport al shunt ing. Not e t he early drainage of blood int o a peripheral port al v ein branc h (ar r ow head).

F igure 12- 18 Hemangioma. Unenhanc ed T 2- w eight ed MR image (A) show s a large hy perint ense hepat ic mass. Gadolinium- enhanc ed T 1- w eight ed image (B) demonst rat es t he c harac t erist ic nodular enhanc ement at t he periphery of t he lesion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1820

12 - Liver

F igure 12- 19 Hy lanized hemangioma. Prec ont rast (A), art erial phase (B), and port al v enous phase (C ) CT images show a low at t enuat ion peripheral mass in t he lef t lobe t hat demonst rat es only a small ill- def ined area of enhanc ement (ar r ow ) on bot h t he art erial and port al v enous phase images. Alt hough t he diagnosis of hy alinized hemangioma may be suggest ed prospec t iv ely , biopsy or surgic al exc ision is required f or def init iv e diagnosis.

Focal Nodular Hyperplasia F oc al nodular hy perplasia (F NH) is t he sec ond most c ommon benign hepat ic t umor af t er hemangioma (141). It oc c urs primarily in y oung w omen, is solit ary in 75% t o 80% of c ases (93,586), and is of t en disc ov ered inc ident ally on abdominal CT or ult rasound examinat ions. It t y pic ally oc c urs in a subc apsular loc at ion and may be pedunc ulat ed (141,880). Alt hough F NH is c onsidered t o be a nonenc apsulat ed lesion, in a small perc ent age of c ases a part ial or c omplet e f ibrous c apsule is present (834). F NH is a benign v asc ular hepat ic neoplasm c omposed of hepat oc y t es, bile duc t s, blood v essels, and Kupf f er

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1821

12 - Liver c ells. It f requent ly c ont ains a c ent ral or ec c ent ric f ibrous sc ar, f rom w hic h f ibrous bands radiat e in a spoke- w heel pat t ern t ow ard t he periphery . T he f ibrous sept a, w hic h separat e t he lesion int o small nodules, c ont ain t hic k-

w alled art eries and bile duc t ules (83). T he indiv idual nodules are c harac t erized by hepat oc y t e prolif erat ion w it h lac k of normal hepat ic arc hit ec t ure, inc luding absenc e of c ent ral v eins or port al t rac t s (83). It has been hy pot hesized t hat F NH result s f rom a c ongenit al v asc ular malf ormat ion t hat induc es f oc al hepat oc ellular hy perplasia (848). In c ont radist inc t ion t o hepat oc ellular adenoma, F NH is not assoc iat ed w it h oral c ont rac ept iv e use (141,392). Alt hough some st udies suggest t hat oral c ont rac ept iv es may promot e t he grow t h of F NH (309,426,571,587,693,856), one st udy has show n no ef f ec t (503). On unenhanc ed CT , F NH usually appears as a homogeneous isoat t enuat ing or slight ly hy poat t enuat ing mass (F igs. 12- 20 and 12- 21). In approximat ely one t hird of P.851 c ases, a w ell- def ined hy poat t enuat ing sc ar may be ident if ied (497,728,859) (see F ig. 12- 20). Bec ause of it s prominent art erial v asc ular supply , F NH undergoes marked enhanc ement during t he art erial phase of c ont rast enhanc ed CT , bec oming apprec iably hy perat t enuat ing relat iv e t o t he hepat ic parenc hy ma (497) (see F igs. 12- 20 and 12- 21). Exc ept f or t he sc ar and f ibrous sept a w hen present , t he enhanc ement of F NH is c harac t erist ic ally homogeneous. One or more large f eeding hepat ic art eries, small c ent ral and sept al art eries, and early draining v eins of t en c an be ident if ied in large lesions (see F ig. 12- 21) (69,123,497,859). During t he hepat ic parenc hy mal phase, F NH usually bec omes isoat t enuat ing or nearly isoat t enuat ing relat iv e t o normal hepat ic parenc hy ma (see F igs. 12- 20 and 12- 21). Unc ommonly , pseudoc apsular enhanc ement may be seen surrounding t he lesion on hepat ic parenc hy mal phase or delay ed images (123,297,551,834). T he pseudoc apsule of F NH result s f rom c ompression of surrounding liv er parenc hy ma, perilesion v essels, and inf lammat ory reac t ion (297). T he f ibrous sc ar, if present , usually remains hy poat t enuat ing during t he art erial phase but may show early art erial enhanc ement (56) (83). Enhanc ement of t he sc ar may be seen on delay ed images due t o t he presenc e of abundant my xomat ous st roma (551).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1822

12 - Liver

F igure 12- 20 F oc al nodular hy perplasia. Prec ont rast CT image (A) show s a large isoat t enuat ing mass (M) in segment IVb of t he liv er. Art erial phase image (B) demonst rat es marked homogeneous enhanc ement of t he mass, w hic h c ont ains a hy poat t enuat ing c ent ral sc ar (ar r ow head). During t he port al v enous phase (C ) t he mass bec omes nearly isoat t enuat ing w it h t he liv er parenc hy ma.

On unenhanc ed MR images, F NH of t en has signal int ensit y c harac t erist ic s similar t o t hat of t he hepat ic parenc hy ma. On T 1- w eight ed images it appears isoint ense or slight ly hy point ense, and on T 2- w eight ed images isoint ense or slight ly hy perint ense relat iv e t o normal hepat ic parenc hy ma (481,514,697,712,728,834) (F ig. 12- 22). Rarely , hy perint ensit y w it hin t he lesion on T 1- w eight ed images may indic at e f at t y c hange, sinusoidal dilat ion, or c opper ac c umulat ion (106,502,654). T he c ent ral sc ar, w hic h is ident if ied on MRI in approximat ely one half t o t hree f ourt hs of c ases, is c harac t erist ic ally hy point ense on T 1- w eight ed images and hy perint ense on T 2- w eight ed images (see F ig. 12- 22). T he hy perint ensit y of t he sc ar on T 2- w eight ed images is due t o t he presenc e of v asc ular c hannels and bile duc t ules (696,834). T he enhanc ement pat t ern of F NH af t er IV administ rat ion of a gadolinium- c ont aining

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1823

12 - Liver c ont rast agent parallels t hat seen on c ont rast - enhanc ed CT , inc luding hy perint ensit y during t he art erial phase, isoint ensit y or near P.852 P.853 isoint ensit y during t he port al v enous (hepat ic parenc hy mal) phase, and enhanc ement of t he sc ar on delay ed images (481,500,834). Oc c asionally ,

art erial phase enhanc ement of t he sc ar may also be seen. F NH t y pic ally show s enhanc ement on delay ed images af t er administ rat ion of Mn- DPDP (134,681,840), Gd- BOPT A (253,254), and Gd- EOB- DT PA (294), and show s signal loss af t er administ rat ion of superparamagnet ic iron oxide (250,254,621,655). Gd- BOPT A and Gd- EOB- DT PA are more ac c urat e t han MnDPDP and superparamagnet ic iron oxide f or diagnosing F NH bec ause P.854 t hey c ombine dy namic art erial phase enhanc ement inf ormat ion w it h delay ed liv er- spec if ic enhanc ement inf ormat ion (254). In addit ion, diagnosis of F NH w it h iron oxide is based on upt ake of t he agent by Kuppf er c ells, w hic h may be present in relat iv ely small numbers in some lesions. F urt hermore, superparamagnet ic iron oxide lac ks adequat e spec if ic it y t o diagnose F NH bec ause ot her hepat ic masses inc luding adenoma, hemangioma, w elldif f erent iat ed hepat oc ellular c arc inoma, and regenerat iv e nodular hy perplasia may also show signal loss af t er superparamagnet ic iron oxide administ rat ion (159,250,631,798,841,882).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1824

12 - Liver

F igure 12- 21 F oc al nodular hy perplasia. A large mass (M) in t he right hepat ic lobe is isoat t enuat ing on t he prec ont rast CT image (A), homogeneously hy perat t enuat ing during t he art erial phase (B) and nearly isoat t enuat ing

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1825

12 - Liver relat iv e t o liv er during t he port al v enous phase (C ). A c ent ral sc ar w as seen

on more c audal images. Not e t he slight hy perat t enuat ion of t he adjac ent liv er on t he port al v enous phase image (ar r ow heads) due t o c ompression of surrounding parenc hy ma. Sagit t al (D) and c oronal (E) maximum int ensit y projec t ion (MIP) images demonst rat e t he large f eeding hepat ic art ery (ar r ow ) and t he large early draining hepat ic v ein (open ar r ow s).

F igure 12- 22 F oc al nodular hy perplasia. A large mass (ar r ow s) in t he c audat e lobe is isoint ense on T 1- w eight ed (A) and T 2- w eight ed (B) images. A c ent ral

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1826

12 - Liver sc ar (ar r ow head) is hy point ense on t he T 1- w eight ed image and hy perint ense on t he T 2- w eight ed image. Art erial phase gadolinium- enhanc ed image (C ) show s int ense enhanc ement of t he mass exc ept f or t he c ent ral sc ar and radiat ing f ibrous sept a. On t he port al v enous phase image (D) t he mass is nearly isoint ense relat iv e t o t he liv er parenc hy ma and t he c ent ral sc ar remains hy point ense. A lat er image (E) show s delay ed enhanc ement of t he c ent ral sc ar.

Alt hough t he t y pic al CT and MRI f eat ures of F NH are c harac t erist ic , at y pic al f eat ures may be seen in 10% t o 20% of c ases (93,586). T hese f eat ures may inc lude c alc if ic at ion, het erogeneous enhanc ement , hy po- t o iso- at t enuat ion or signal int ensit y during t he art erial phase, a low signal int ensit y sc ar on T 2w eight ed images, or a prominent pseudoc apsule (93,96,123,297,767). Consequent ly , t here may be ov erlap bet w een t he imaging appearanc e of F NH and t hat of ot her hepat ic masses inc luding hepat oc ellular adenoma, hepat oc ellular c arc inoma, f ibrolamellar c arc inoma, int rahepat ic c holangioc arc inoma, hepat ic hemangioma, and hy perv asc ular met ast ases (481,500,728). F or example, hepat oc ellular c arc inoma may show marked art erial enhanc ement and may hav e a c ent ral sc ar or an area of sc ar- like nec rosis t hat is high in signal int ensit y on T 2- w eight ed images (264). How ev er, in most c ases, malignant lesions c an be dif f erent iat ed f rom F NH bec ause of t heir het erogeneous enhanc ement pat t ern. Nev ert heless, in some c ases it may be dif f ic ult t o make a def init iv e diagnosis of F NH based on t he CT or MRI f eat ures alone. Hepat ic sc int igraphy w it h t ec hnet ium- 99m- labeled sulf ur c olloid may be usef ul in c onf irming t he diagnosis. Bec ause F NH c ont ains Kupf f er c ells, it c onc ent rat es sulf ur c olloid (683,859). In approximat ely one half of c ases, t he degree of radiot rac er ac c umulat ion is similar t o t hat of t he normal hepat ic parenc hy ma, and in 10% of c ases inc reased c onc ent rat ion of c olloid is seen (388,683,859). In t he remaining 40% of pat ient s F NH appears as a phot openic def ec t , indic at ing t hat t he Kupf f er c ells in t he lesion hav e c onc ent rat ed t he sulf ur c olloid t o a lesser degree t han t he surrounding liv er. Regenerat iv e nodules, f oc al hepat ic st eat osis, and some hepat oc ellular adenomas may also c onc ent rat e sulf ur c olloid (388,476). How ev er, in t he proper c linic al set t ing, t he CT or MRI f eat ures in c ombinat ion w it h normal upt ake w it hin t he mass on sulf ur c olloid sc an st rongly suggest t he diagnosis of F NH. T he f inding of inc reased sulf ur c olloid c onc ent rat ion is spec if ic f or F NH (388). Anot her sc int igraphic st udy t hat c an est ablish t he diagnosis of F NH is hepat obiliary

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1827

12 - Liver sc anning w it h an agent suc h as t ec hnet ium 99m diet hy l- iminodiac et ic ac id. T he abnormal biliary drainage of F NH result s in upt ake and delay ed exc ret ion of t he agent , rev ealing t he lesion as a “ hot spot ” w it hin t he liv er on delay ed images (61). Alt hough experienc e is st ill limit ed, t he c ont rast agent s t hat likely w ill be t he most usef ul f or c harac t erizing F NH are t he liv er- spec if ic hepat obiliary MR c ont rast agent s Gd- BOPT A and Gd- EOB- DT PA. T he ext rac ellular propert ies of t hese agent s c an demonst rat e t he t y pic al v asc ular enhanc ement pat t ern of F NH on dy namic post c ont rast images. In addit ion, delay ed imaging demonst rat es upt ake of t he agent by hepat oc y t es w it hin t he lesion,

demonst rat ing t he hepat oc ellular origin of t he mass (253,254). Alt hough ot her primary hepat oc ellular lesions suc h as hepat oc ellular adenoma and hepat oc ellular c arc inoma also enhanc e w it h t hese agent s, t he c ombinat ion of t he dy namic and delay ed imaging f eat ures usually is adequat e t o dist inguish bet w een F NH and t he ot her lesions. Superparamagnet ic iron oxide (SPIO) MR c ont rast agent s also are c apable of c harac t erizing F NH based on upt ake of t he agent s by Kuppf er c ells w it hin t he lesion. How ev er, bec ause ot her hepat ic masses inc luding adenoma, hemangioma, w ell- dif f erent iat ed hepat oc ellular c arc inoma, and regenerat iv e nodular hy perplasia also c an demonst rat e signal loss af t er SPIO administ rat ion, SPIO- enhanc ed MR st udies perf ormed t o diagnose F NH must be int erpret ed w it h c aut ion. One c omparat iv e st udy f ound Gd- BOPT A t o be superior t o SPIOenhanc ed MRI f or t he ident if ic at ion and c harac t erizat ion of F NH (254). When dif f erent iat ion of F NH f rom ot her neoplasms is not possible on t he basis of t he imaging f indings, f ollow - up imaging, needle biopsy , or surgic al exc ision may be nec essary . If f ollow - up imaging is c hosen, it is import ant t o be aw are t hat alt hough most lesions remain st able, a minorit y may demonst rat e an inc rease or dec rease in size ov er t ime (349,426,503). If a biopsy is perf ormed, t he samples should inc lude t he f ibrous sc ar, if present , bec ause diagnost ic bile duc t ules may be f ound only in t his region of t he t umor (93).

Hepatocellular Adenoma Hepat oc ellular adenoma is an unc ommon benign primary hepat ic neoplasm c onsist ing of sheet s of normal- appearing hepat oc y t es but lac king t he normal ac inar arc hit ec t ure of t he surrounding hepat ic parenc hy ma (880). T he hepat oc y t es may be ric h in lipid or gly c ogen, and Kupf f er c ells are oc c asionally present , but bile duc t s and port al t rac t s are absent

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1828

12 - Liver (141,245,376). T he lesion may be surrounded by a f ibrous c apsule. Hepat oc ellular adenomas are usually solit ary , but mult iple adenomas are not

unc ommon (302,632). T hey oc c ur predominant ly in w omen of c hildbearing age, and t heir presenc e is st rongly assoc iat ed w it h t he use of oral c ont rac ept iv es (181,390). Alt hough adenomas c an regress or c omplet ely disappear af t er w it hdraw al of oral c ont rac ept iv es (182,367), t hey may c ont inue t o enlarge despit e disc ont inuat ion of t he drug (488). Anabolic st eroids are implic at ed as a c ause of hepat oc ellular adenoma and hepat oc ellular c arc inoma in men (62,141). Pat ient s w it h gly c ogen st orage disease are at risk f or dev eloping mult iple adenomas as w ell as hepat oc ellular c arc inoma (135,164,434,467,532). Hepat oc ellular adenoma has a t endenc y P.855 t o undergo spont aneous hemorrhage. Alt hough pat ient s w it h an unc omplic at ed adenoma are usually asy mpt omat ic , t hose w it h large or hemorrhagic lesions generally present w it h abdominal pain. Rare inst anc es of malignant degenerat ion of hepat oc ellular adenomas hav e been report ed (212,246,580,800). Bec ause t he imaging appearanc e of hepat oc ellular adenoma is highly v ariable and ov erlaps w it h t hat of hepat oc ellular c arc inoma, surgic al resec t ion is generally rec ommended.

F igure 12- 23 Hepat oc ellular adenoma. Prec ont rast CT image (A) show s a large hy poat t enuat ing hepat ic mass. A post c ont rast port al v enous phase image (B) show s moderat e het erogeneous enhanc ement of t he mass.

T he CT and MRI appearanc es of hepat oc ellular adenoma are v aried and nonspec if ic . On unenhanc ed CT images t he lesion may be hy poat t enuat ing due t o t he presenc e of int rac ellular lipid (see F ig. 12- 23), old hemorrhage or nec rosis, or it may be hy perat t enuat ing ow ing t o rec ent hemorrhage or large

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1829

12 - Liver

amount s of gly c ogen (252,302,497). Hemorrhagic adenomas are het erogeneous (F ig. 12- 24), w hereas unc omplic at ed lesions are homogeneous in appearanc e. Rarely , c alc if ic at ion may be ident if ied (302). Af t er IV c ont rast medium administ rat ion, adenoma of t en demonst rat es moderat e enhanc ement during t he art erial and early port al v enous phases of enhanc ement (497) (F ig. 12- 25). Alt hough t here is ov erlap, t he degree of art erial phase enhanc ement of most adenomas t ends t o be somew hat less t han t hat seen w it h F NH (702). Exc ept f or areas of nec rosis, hemorrhage or f at , t he enhanc ement is homogeneous or nearly homogeneous in 80% of c ases (252). In approximat ely 25% of c ases, a t hin t umor c apsule c an be ident if ied (302). T he c apsule is hy poat t enuat ing relat iv e t o surrounding liv er and adenoma on hepat ic art erial phase images and hy perat t enuat ing on port al v enous phase images. T he MRI appearanc e of adenoma is equally v aried. Most lesions are het erogeneous in signal int ensit y (16,128,632). T he majorit y of hepat oc ellular adenomas are hy perint ense t o surrounding hepat ic parenc hy ma on T 1w eight ed images and isoint ense or hy perint ense on T 2- w eight ed images (16,632) (F ig. 12- 26). T he hy perint ensit y on T 1- w eight ed images is generally relat ed t o t he presenc e of lipid (632) or hemorrhage (16,128) in t he lesion. Opposed- phase T 1- w eight ed images may demonst at e dec reased signal int ensit y w it hin t he lesion relat iv e t o t he signal int ensit y on t he in- phase images, indic at ing t he presenc e of int rac ellular lipid (F igs. 12- 26 and 12- 27). A low - signal- int ensit y c apsule, similar t o t hat report ed w it h hepat oc ellular c arc inoma, is seen in approximat ely one t hird of hepat oc ellular adenomas (16,697). On dy namic c ont rast - enhanc ed gradient ec ho imaging, adenoma usually appears hy perint ense t o hepat ic parenc hy ma, but may be isoint ense or hy point ense (F ig. 12- 28) (16). Some hepat oc ellular adenomas show signal loss af t er administ rat ion of superparamagnet ic iron oxide due t o pooling of t he c ont rast agent in peliosis- like dilat ed v essels or phagoc y t ic upt ake by endot helial c ells (159,250). Bec ause of t he v aried appearanc es of hepat oc ellular adenoma, dif f erent ial diagnosis may be dif f ic ult . When at t empt ing t o dist inguish adenoma f rom F NH, t he f indings of hemorrhage or lipid w it hin t he lesion st rongly support a diagnosis of adenoma. T he presenc e of a c ent ral sc ar st rongly support s t he diagnosis of F NH, espec ially if t he sc ar is hy point ense on T 1- w eight ed images, hy perint ense on T 2- w eight ed images, and show s delay ed enhanc ement . F ibrolamellar hepat oc ellular c arc inoma usually c an be dist inguished f rom adenoma bec ause it generally c ont ains a large c ent ral or ec c ent ric sc ar, of t en

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1830

12 - Liver w it h c alc if ic at ion and radiat ing f ibrous sept a, and it s enhanc ement is

het erogeneous. In some c ases, how ev er, based on t he CT or MRI appearanc e, it may be dif f ic ult t o dist inguish w it h c onf idenc e bet w een hepat oc ellular adenoma and hepat oc ellular c arc inoma oc c urring in a pat ient w it hout underly ing c hronic liv er disease. Liv er adenomat osis is a rare c linic al ent it y , c harac t erized by numerous hepat ic adenomas (arbit rarily , more t han 10) P.856 assoc iat ed w it h inc reased serum alkaline phosphat ase and gammaglut amy lt ransf erase lev els, in pat ient s w it hout gly c ogen st orage disease (207,251). Bot h men and w omen are af f ec t ed, alt hough t here is a f emale predominanc e (14 of 15 pat ient s in t he largest report ed series) (251). Most pat ient s are relat iv ely y oung (av erage age of 36 y ears) and hav e an ot herw ise normal liv er, but many hav e a c ongenit al or ac quired abnormalit y of t he hepat ic v asc ulat ure, w hic h may predispose t hem t o t he dev elopment of t hese adenomat ous liv er lesions (251). T he imaging appearanc e and hist ology of t he lesions in liv er adenomat osis are similar t o t hose of sporadic hepat oc ellular adenomas; how ev er, unlike most sporadic adenomas, t hey do not appear t o be st eroid dependent and do not regress w it h st eroid w it hdraw al or bloc kage (251,675). In f ac t , t he size and number of lesions inc reases w it h t ime (251). Pat ient s w it h liv er adenomat osis appear t o be at inc reased risk f or P.857 dev elopment of hepat oc ellular c arc inoma and should be monit ored w it h CT or MRI and serum alpha- f et oprot ein lev els (251,434,675).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1831

12 - Liver

F igure 12- 24 Rupt ured hepat oc ellular adenoma. Prec ont rast CT image (A) show s a large het erogeneous mass (ar r ow s) near t he dome of t he liv er. Cent ral areas of hy perint ensit y represent hemorrhage. Not e t he high at t enuat ion perihepat ic blood (ar r ow heads). Cont rast - enhanc ed image (B) show s enhanc ement of t he peripheral int ac t port ion of t he mass (open ar r ow s). T he hemorrhagic port ion of t he mass does not enhanc e. Not e loss of int egrit y of t he liv er c apsule ant erolat erally . Coronal v olume- rendered image (C ) show s t he peripherally enhanc ing mass, rupt ured liv er c apsule, and perihepat ic blood (ar r ow heads).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1832

12 - Liver

F igure 12- 25 Hepat oc ellular adenoma. Cont rast - enhanc ed port al v enous phase CT image demonst rat es a slight ly hy perat t enuat ing, het erogeneously enhanc ing v asc ular hepat ic mass (ar r ow s).

F igure 12- 26 Hepat oc ellular adenoma. A mass in segment VII of t he liv er is hy perint ense on an in- phase T 1- w eight ed gradient ec ho image (A) and show s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1833

12 - Liver

marked signal loss on an opposed- phase image (B), indic at ing t hat it c ont ains lipid. T he mass is high in signal int ensit y on a T 2- w eight ed image (C ).

F igure 12- 27 Hepat oc ellular adenoma. In- phase T 1- w eight ed spoiled gradient - ec ho MR image (A) show s a large isoint ense hepat ic mass (M). Out of - phase image (B) demonst rat es dif f use dec rease in signal int ensit y w it hin t he mass due t o t he presenc e of int rac ellular lipid.

F igure 12- 28 Hepat oc ellular adenomas. A large mass (M) in t he lef t lobe of t he liv er is isoint ense on T 1- w eight ed (A) and T 2- w eight ed (B) images exc ept

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1834

12 - Liver f or int ernal het erogeneit y . A smaller mass (ar r ow ) t hat is hy point ense w it h a hy perint ense rim on t he T 1- w eight ed image and hy perint ense on t he T 2-

w eight ed image is a hemorrhagic adenoma. T he mass bec omes hy perint ense on t he art erial phase gadolinium- enhanc ed image (C ) and slight ly hy point ense on t he port al v enous phase image (D). T he smaller enhanc ing masses (ar r ow heads) on t he art erial phase image are addit ional adenomas.

P.858

Rare Benign Tumors Benign lipomat ous t umors of t he liv er inc lude lipoma, angiomy olipoma, my elolipoma, and angiomy elolipoma. Angiomy olipoma is a benign, unenc apsulat ed mesenc hy mal t umor t hat is c omposed of v ary ing proport ions of smoot h musc le, t hic k- w alled blood v essels, and mat ure adipose t issue (101,813). Lipomas or angiomy olipomas hav e been f ound in 6% t o 10% of pat ient s w it h t uberous sc lerosis but c an oc c ur in pat ient s w it hout t he disease (101,345,573,679). T he lesions v ary w idely in size and may be solit ary or mult iple. T he imaging diagnosis of angiomy olipoma is based on t he ident if ic at ion of f at w it hin t he mass (F igs. 12- 29 and 12- 30). T he appearanc e on CT and MRI depends on t he amount of f at present , w hic h may v ary f rom 5% t o 90% of t he mass (244). In most c ases, f at w it hin t he mass c an be ident if ied by it s low at t enuat ion v alue (less t han - 20 HU) on CT (see F ig. 1229) (5,43,94,105,288,474,654,889) or it s high signal int ensit y on T 1- w eight ed MR images and signal drop on f at - suppressed images (see F ig. 12- 30) (43,105,150,288). T hin sec t ion CT and MRI w it h f at suppression may be helpf ul f or demonst rat ing small amount s of f at (288,492). T he nonf at c omponent s of t he lesion c harac t erist ic ally show marked early and prolonged enhanc ement (see F igs. 12- 29 and 12- 30), and prominent c ent ral enhanc ing v essels may be ident if ied (5,560,889). Caut ion must be exerc ised in diagnosing a benign f at t y mass, how ev er, if subst ant ial sof t t issue c omponent s are present bec ause ot her hepat ic masses, inc luding hepat oc ellular c arc inoma, c an c ont ain f at . T he marked early and P.859 prolonged enhanc ement of angiomy olipoma and t he absenc e of a c apsule hav e been suggest ed as helpf ul signs in dist inguishing it f rom f at - c ont aining hepat oc ellular c arc inoma, w hic h enhanc es markedly during t he art erial phase but w ashes out rapidly during t he port al v enous phase (5,560,889). How ev er, dist inc t ion bet w een angiomy omlipoma and hepat oc ellular c arc inoma w it h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1835

12 - Liver st eat osis may be dif f ic ult based on enhanc ement pat t ern alone. Lesions t hat c ont ain v ery lit t le f at may be dif f ic ult or impossible t o diagnose w it hout a biopsy (43,791,902).

F igure 12- 29 Hepat ic angiomy olipoma. Cont rast - enhanc ed CT image show s a het erogeneously enhanc ing hepat ic mass t hat c ont ains f oc i of mac rosc opic f at (ar r ow ). Reproduc ed f rom Prasad SR, Wang H, Rosas H, et al. F at - c ont aining lesions of t he liv er: radiologic - pat hologic c orrelat ion. Radiogr aphic s. 2005;25: 321–331.

Hepat ic my elolipoma is a benign t umor c ont aining normal my eloid and ery t hroid prec ursors in addit ion t o mat ure f at c ells (365). It s CT and MRI appearanc e is indist inguishable f rom t hat of lipoma and angiomy olipoma. Adrenal rest t umor is an ec t opic c ollec t ion of adrenoc ort ic al c ells in an ext raadrenal sit e (790). T he t umor may be nonf unc t ional or hormonally ac t iv e, manif est ing as an endoc rine sy ndrome (136). Among t he hist ologic c omponent s of t he t umor, t he presenc e of f at is t he most c harac t erist ic f eat ure. Dif f erent iat ion of hepat ic adrenal rest t umor f rom angiomy olipoma or hepat oc ellular c arc inoma w it h st eat osis may be dif f ic ult at imaging and on hist ologic analy sis. Mesenc hy mal hamart oma of t he liv er (also ref erred t o as ly mphangioma, bile c ell f ibroadenoma, hamart oma, c av ernous ly mphangiomat oid t umor, and c y st ic hamart oma) is an unc ommon c y st ic mass t hat oc c urs primarily in c hildren below t he age of 3 y ears (686) but is seen oc c asionally in adult s (191,340,784). It is t hought t o be a c ongenit al abnormalit y originat ing in t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1836

12 - Liver c onnec t iv e t issue along t he port al t rac t s (784). Hist ologic ally , t he t umor c onsist s of c onnec t iv e t issue w it h a disorganized mixt ure of hepat oc y t es, abnormal bile duc t s, and mesenc hy me (686). T he c y st s represent areas of

degenerat ion w it h f luid ac c umulat ion. T he liv er may inc rease rapidly in size as f luid ac c umulat es in t he degenerat ing mesenc hy me of t he lesion (880). T he CT appearanc e of mesenc hy mal hamart oma ranges f rom t hat of a solid mass c ont aining mult iple small c y st s t o a mult iloc ular c y st ic mass w it h sept a (395,686,752). T he solid port ions of t he mass enhanc e af t er IV c ont rast medium administ rat ion (191). Hemangiendot helioma, w hic h usually oc c urs during inf anc y , is disc ussed in Chapt er 24. Biliary c y st adenoma is disc ussed in c onjunc t ion w it h biliary c y st adenoc arc inoma lat er in t his c hapt er under “ Rare Malignant T umors.”

MALIGNANT HEPATIC TUMORS Hepatocellular Carcinoma T he inc idenc e of hepat oc ellular c arc inoma (HCC) v aries w idely , being most c ommon in Sout heast Asia and sub- Saharan Af ric a and muc h less c ommon in Nort h Americ a and West ern Europe (880). How ev er, t he inc idenc e of HCC is inc reasing in Nort h Americ a and Europe (59,185,802). In t he Unit ed St at es, t he age- adjust ed inc idenc e rat es hav e doubled in t he past 2 dec ades (185). HCC ac c ount s f or 90% of primary malignant hepat ic neoplasms and is t he f if t h most c ommon c anc er w orldw ide. Men are af f ec t ed 3 t imes more f requent ly t han w omen (185). Eight y perc ent (80%) t o 90% of c ases of HCC oc c ur in pat ient s w it h underly ing c irrhosis (741). T he major risk f ac t ors f or HCC are inf ec t ion f rom hepat it is C and B v iruses and heav y alc ohol c onsumpt ion (193). Rare risk f ac t ors inc lude hemoc hromat osis, О±1- ant it ry psin disease, ingest ion of af lat oxins, gly c ogen st orage disease (part ic ularly t y pes I and III), and Wilson disease (185). Hepat oc ellular c arc inoma may be solit ary , mult if oc al, or, less c ommonly , dif f usely inf ilt rat ing. On t he basis of gross pat hology , HCC is c at egorized int o t hree pat t erns: nodular, massiv e, and dif f use (880). T he nodular pat t ern is most c ommon and c onsist s of one or mult iple nodules t hroughout t he liv er. Of t en, t here is one dominant nodule w it h one or more adjac ent sat ellit e nodules. In t he massiv e pat t ern a large disc ret e mass replac es most or all of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1837

12 - Liver one hepat ic lobe. T he dif f use pat t ern is least c ommon and is inv ariably assoc iat ed w it h c irrhosis. It c onsist s of t iny indist inc t t umor nodules sc at t ered t hroughout t he liv er t hat are dif f ic ult t o dist inguish f rom c irrhot ic nodules. HCC c an also be c lassif ied based on grow t h c harac t erist ic s. Expansiv e t umors t end t o be w ell dif f erent iat ed and relat iv ely slow ly grow ing, w hereas inv asiv e t umors t end t o be poorly dif f erent iat ed and demonst rat e aggressiv e grow t h pat t erns (610). Expansiv e t umors are w ell def ined and f requent ly surrounded by a f ibrous c apsule, w hereas inv asiv e t umors are ill

def ined and nonenc apsulat ed. Serum О±- f et oprot ein lev els are of t en elev at ed in pat ient s w it h large t umors. How ev er, in P.860 pat ient s w it h small t umors, t he serum О±- f et oprot ein lev el is f requent ly normal.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1838

12 - Liver

F igure 12- 30 Hepat ic angiomy olipoma. In- phase T 1- w eight ed spoiled gradient ec ho MR image (A) show s a hy point ense mass in t he right hepat ic lobe t hat c ont ains sev eral f oc i of hy perint ensit y (ar r ow ) due t o mac rosc opic f at . Out of - phase image (B) demonst rat es a blac k ring surrounding one of t he high signal int ensit y f oc i indic at ing an int erf ac e bet w een f at prot ons and surrounding w at er prot ons (ar r ow head). T 2- w eight ed image (C ) show s t hat t he mass is hy perint ense and t hat t he int ernal f oc i of f at are higher in signal int ensit y relat iv e t o t he rest of t he lesion. T 2- w eight ed image w it h f at

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1839

12 - Liver suppression (D) show s t hat t he hy perint ense f oc i w it hin t he lesion on t he non–f at - suppressed image (C ) bec ome hy point ense, c onf irming t hat t hey represent f oc i of mac rosc opic f at . Art erial phase T 1- w eight ed gadoliniumenhanc ed image (E) show s marked het erogeneous enhanc ement of t he non–f at - c ont aining port ions of t he mass.

Hepat oc ellular c arc inoma is a t umor c onsist ing of abnormal hepat oc y t es arranged in a t rabec ular, sinusoidal pat t ern in w hic h t he t rabec ulae are separat ed by sinusoidal blood- f illed spac es (880). T he sinusoidal spac es are more prominent (peliot ic c hange) in large and poorly dif f erent iat ed t umors (347). HCC is a v asc ular t umor t hat rec eiv es it s blood supply f rom t he hepat ic art ery . It has a t endenc y t o inv ade v asc ular st ruc t ures, more c ommonly t he port al v ein t han t he hepat ic v ein (F igs. 12- 31 and 12- 32). Venous inv asion is more c ommon w it h higher grade and larger t umors (780) P.861 and is assoc iat ed w it h a poorer pat ient prognosis (495). Art erioport al shunt ing, a c harac t erist ic f eat ure of HCC, is w ell demonst rat ed at CT (F igs. 12- 32 and 12- 33) or MRI (316,495,609). Like hepat oc ellular adenoma, HCC may undergo spont aneous hemorrhage (526). Large subc apsular lesions may rupt ure, c ausing hemoperit oneum (F ig. 12- 34). Large t umors are of t en hist ologic ally het erogeneous, result ing in a mosaic pat t ern t hat c an be apprec iat ed bot h on pat hologic analy sis and on diagnost ic imaging st udies (F ig. 12- 35) (117,608,780,781). T he mosaic pat t ern represent s c onf luent small t umor nodules w it h int erspersed sept a and areas of nec rosis (119,608,781). Oc c asionally , a prominent c ent ral sc ar is present (696). Anot her pat hologic f eat ure of some HCCs is f at t y met amorphosis (F igs. 12- 35 and 12- 36), w hic h is ident if ied more f requent ly at MRI t han at CT (141,347,697,897).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1840

12 - Liver

F igure 12- 31 Dif f usely inf ilt rat ing hepat oc ellular c arc inoma w it h port al v ein inv asion. Art erial phase CT image show s enhanc ing t umor t hrombus expanding t he lef t and right port al v eins (ar r ow s). T he elongat ed hy poat t enuat ing area w it hin t he port al v ein (ar r ow head) is bland t hrombus.

F igure 12- 32 Dif f usely inf ilt rat ing hepat oc ellular c arc inoma w it h art erioport al shunt ing and port al v ein inv asion. Art erial phase CT image (A) of t he liv er show s dif f use het erogeneit y w it hin t he ant erior segment of t he right lobe and medial segment of t he lef t lobe. Not e t hat t he port al v ein (ar r ow ) enhanc es bright ly on t his art erial phase image, indic at ing art erioport al shunt ing. T umor t hrombus inc omplet ely f ills t he right and lef t port al v eins (ar r ow heads). Port al v enous phase image (B) more c learly demonst rat es t he hepat ic parenc hy mal het erogeneit y and port al v ein t umor t hrombus (ar r ow heads).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1841

12 - Liver T he CT appearanc e of HCC is v ariable and depends not only on t he size, v asc ularit y , hist ologic c omposit ion, and grow t h pat t ern of t he t umor, but on t he CT t ec hnique used. Most HCCs are hy poat t enuat ing on prec ont rast

images, but a signif ic ant minorit y are isoat t enuat ing t o liv er parenc hy ma prior t o IV c ont rast medium administ rat ion (313,410,803). Some of t he isoat t enuat ing lesions c an be ident if ied on unenhanc ed images by t he presenc e of a hy poat t enuat ing rim, w hic h represent s t he t umor c apsule (313), or by a f oc al bulge in t he c ont our of t he liv er. On rare oc c asions, t he mass may ext end exophy t ic ally bey ond t he c onf ines of t he liv er and simulat e an ext rahepat ic mass (473). Areas of nec rosis or f at t y met amorphosis appear as hy poat t enuat ing f oc i w it hin t he mass, w hereas rec ent hemorrhage may produc e areas of hy perat t enuat ion. Calc if ic at ion is ident if ied in approximat ely 5% t o 10% of HCCs (117,219,313,347,780,803). Ev en w hen art erial and port al v enous phase imaging is perf ormed, approximat ely 3% of HCCs may be ident if ied only on t he prec ont rast images (613). Prec ont rast images are also import ant t o ident if y lesions t hat are hy perat t enuat ing prior t o c ont rast medium administ rat ion (e.g., f rom hemorrhage or iron deposit ion) t o av oid mist aking t he inc reased at t enuat ion on post c ont rast images as lesion enhanc ement . Hepat oc ellular c arc inoma is more easily ident if ied and bet t er c harac t erized on dy namic c ont rast - enhanc ed CT . Proper imaging t ec hnique is c rit ic al f or CT det ec t ion of HCC. A rapid injec t ion rat e (e.g., 4 t o 5 mL/sec ond) improv es det ec t ion of P.862 small HCCs c ompared w it h a slow er injec t ion rat e (e.g., 2 mL/sec ond) (541). Images should be ac quired during t he lat e hepat ic art erial and port al v enous (hepat ic parenc hy mal) phases of enhanc ement . Imaging during t he lat e hepat ic art erial phase improv es lesion t o liv er t issue c ont rast and HCC det ec t ion rat e c ompared w it h imaging during t he early art erial phase (211,417). Alt hough some st udies hav e demonst rat ed t hat a small perc ent age of HCC nodules are demonst rat ed only on delay ed phase imaging (3 t o 6 minut es af t er c ont rast medium administ rat ion) (298,383,385,462), many inv est igat ors do not ac quire t his addit ional set of images. Bec ause of it s art erial blood supply , HCC c harac t erist ic ally appears as a t ransient ly hy perat t enuat ing mass during t he hepat ic art erial phase of enhanc ement (F ig. 12- 37), but approximat ely 20% of HCC nodules appear hy poat t enuat ing relat iv e t o liv er during t he hepat ic art erial phase (33). Approximat ely 15%

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1842

12 - Liver more HCC t umor nodules and 33% addit ional pat ient s w it h HCC are ident if ied w hen art erial phase imaging is added t o unenhanc ed and port al v enous phase imaging. F urt hermore, approximat ely 10% of HCCs and 24% of pat ient s w it h HCC are demonst rat ed only on t he art erial phase images (see F ig. 12- 37) (33,613). T he depic t ion of addit ional lesions during t he art erial phase is most marked f or lesions less t han or equal t o 3 c m (121,531,595). Small HCCs t end t o enhanc e homogeneously during t he hepat ic art erial phase of enhanc ement , w hereas larger lesions usually enhanc e het erogeneously . T he presenc e of irregularly c ont oured and branc hing v essels or randomly dist ribut ed hy perat t enuat ing and hy poat t enuat ing regions w it hin a lesion during t he art erial phase of enhanc ement is c harac t erist ic of HCC (588). A f ibrous c apsule, w hen present , c harac t erist ic ally remains unenhanc ed during t he art erial phase (F ig. 12- 38) (317). In t he port al v enous (hepat ic parenc hy mal) phase of enhanc ement , HCC may bec ome isoat t enuat ing w it h hepat ic parenc hy ma or may be ident if ied as a hy poat t enuat ing mass. During t his phase, t he t umor c apsule and sept a generally appear hy perat t enuat ing (317,780), and t umors t hat demonst rat e a mosaic pat t ern appear het erogeneous in at t enuat ion (781) (see F ig. 12- 35). A small perc ent age of HCC nodules are ident if ied only on delay ed (3 t o 6 minut es) post c ont rast images as hy poat t enuat ing nodules, ev en w hen art erial phase images are ac quired (298,299,383,385,462). P.863 On delay ed images, areas of f ibrosis, inc luding t he c apsule and sept a, usually

demonst rat e prolonged enhanc ement (317,898). Dif f usely inf ilt rat ing HCCs are best seen during t he lat e hepat ic art erial phase as ill- def ined, v aguely nodular areas of hy perat t enuat ion w it hout disc ret e margins (F igs. 12- 39 and 12- 40), but suc h lesions may be dif f ic ult t o det ec t during any phase of enhanc ement .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1843

12 - Liver F igure 12- 33 Hepat oc ellular c arc inoma w it h art erioport al shunt ing. Prec ont rast CT image (A) in a pat ient w it h c irrhosis show s slight hy poat t enuat ion of t he lef t hepat ic lobe. Very dense iodized oil f rom c hemoembolizat ion of a large hepat oc ellular c arc inoma is present at t he periphery of t he lef t lobe. Art erial phase c ont rast - enhanc ed image (B)

demonst rat es t hat only a small port ion of t he dif f use lef t lobe t umor has been embolized. Int ense art erial phase enhanc ement of t he port al v ein (ar r ow ) indic at es art erioport al shunt ing.

F igure 12- 34 Hemorrhagic hepat oc ellular c arc inoma. Cont rast - enhanc ed CT image show s mult iple low at t enuat ion lesions sc at t ered t hroughout t he liv er. A larger subc apsular lesion in t he lef t hepat ic lobe has rupt ured, result ing in hemoperit oneum. T he area of bright c ont rast enhanc ement at t he periphery of t he liv er indic at es ac t iv e ext rav asat ion (ar r ow ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1844

12 - Liver

F igure 12- 35 Hepat oc ellular c arc inoma. Cont rast - enhanc ed CT images (A, B) show a large het erogeneously enhanc ing mass in t he right hepat ic lobe. Int ernal sept at ions and areas of degenerat ion giv e t he mass a “ mosaic ” pat t ern, w hic h is also demonst rat ed on a c oronal v olume- rendered image (C ). T he v ery low at t enuat ion areas in t he inf erior port ion of t he mass are areas of f at t y degenerat ion.

F igure 12- 36 Hepat oc ellular c arc inoma w it h f at t y met amorphosis. Prec ont rast (A) and c ont rast - enhanc ed (B) CT images show a large hy poat t enuat ing mass

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1845

12 - Liver in t he right hepat ic lobe. An area of f at at t enuat ion post eriorly (ar r ow ) represent s f at t y met amorphosis w it hin t he t umor.

Cont rast - enhanc ed CT is c apable of demonst rat ing bot h v asc ular inv asion and art erioport al shunt ing assoc iat ed w it h HCC (108,304,316,414,495,499). Port al or hepat ic P.864 v ein t umor t hrombus appears as a hy poat t enuat ing f illing def ec t w it hin t he expanded v asc ular lumen. Int rav asc ular t umor t hrombus may show homogeneous or st reaky c ont rast enhanc ement , dist inguishing it f rom bland t hrombus (495,499) (see F igs. 12- 31, 12- 32, and 12- 40). Signs of art erioport al shunt ing inc lude early or prolonged enhanc ement of t he port al v ein (see F igs. 12- 32 and 12- 33) and t ransient segment al, lobar or w edgeshaped hy perenhanc ement peripheral t o t he t umor (316,572). Hepat oc ellular c arc inoma may c ause biliary duc t al dilat ion by c ompressiv e ef f ec t or, less c ommonly , by direc t duc t al inv asion. Lesions t hat oc c ur in nonc irrhot ic liv ers t end t o be larger and are more f requent ly solit ary t han t hose oc c urring in c irrhot ic liv ers (F ig. 12- 41) (67,872).

F igure 12- 37 Hepat oc ellular c arc inoma. Art erial phase CT image (A) show s a w ell- def ined hy perat t enuat ing mass (ar r ow ) in segment VII of t he liv er. On t he port al v enous phase image (B) t he mass has bec ome isoat t enuat ing and is no longer ident if ied.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1846

12 - Liver

F igure 12- 38 Mult if oc al hepat oc ellular c arc inoma. Art erial phase CT images (A, B) show a large het erogeneously enhanc ing mass w it h mult iple adjac ent sat ellit e lesions. A t hin hy poat t enuat ing f ibrous c apsule (ar r ow heads) surrounds t he large mass.

T he MRI appearanc e of HCC c orrelat es c losely w it h it s gross pat hologic f eat ures (117,177,332,347,599). Charac t erist ic f indings, alt hough not alw ay s present , inc lude a c apsule (F ig. 12- 42), c ent ral sc ar, int rat umoral sept a, daught er nodules, and t umor t hrombus in port al or hepat ic v eins. On T 1w eight ed images HCC may be hy point ense, isoint ense, or hy perint ense relat iv e t o hepat ic parenc hy ma. HCC is isoint ense or hy perint ense on T 1- w eight ed images in 47% t o 62% of pat ient s (332,347). T hus, hy perint ensit y on T 1w eight ed images (see F ig. 12- 42), w hic h may be due t o hemorrhage or high lipid, gly c ogen, c opper, or iron c ont ent (177,697), c an help dif f erent iat e HCC f rom hepat ic met ast ases, w hic h are nearly alw ay s hy point ense on T 1- w eight ed images. How ev er, benign P.865 hepat ic masses, inc luding hepat oc ellular adenoma, angiomy olipoma, and my elolipoma, also c an appear hy perint ense on T 1- w eight ed images. Sev ent y perc ent (70%) t o 90% of HCCs are hy perint ense on T 2- w eight ed images, w it h t he remainder being isoint ense and rarely hy point ense (174,332,347,373). Half of HCCs, primarily t hose great er t han 3 c m in diamet er, demonst rat e a het erogeneous mosaic pat t ern t hat is seen bet t er on T 2- w eight ed t han on T 1w eight ed images (347). Loc alized hy perint ense f oc i on T 2- w eight ed images c orrespond t o areas of dilat ed sinusoids (peliot ic c hange) w it hin t he t umor (347). A t umor c apsule, seen more f requent ly on T 1- w eight ed images, has been ident if ied in 24% t o 78% of HCCs (177,332,347) (see F ig. 12- 42). On T 1-

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1847

12 - Liver w eight ed images t he c apsule appears as a hy point ense rim, w hereas on T 2w eight ed images it c an appear as eit her a single hy point ense rim or a doublelay ered peripheral band (177,332,347). An inner, low - signal- int ensit y lay er

c orresponds t o f ibrous t issue (t he c apsule), and an out er high- signal- int ensit y lay er c orresponds t o a zone of c ompressed small v essels or new ly f ormed bile duc t s (332). Alt hough P.866 c harac t erist ic of HCC, a c apsule is not spec if ic f or t his t umor and c an be seen w it h adenoma and, less c ommonly , F NH (697,834).

F igure 12- 39 Mult if oc al hepat oc ellular c arc inoma. Art erial phase c ont rast enhanc ed CT image show s dif f use nodular, het erogeneous hy perat t enuat ion of t he right hepat ic lobe and medial segment of t he lef t lobe w it h mult iple addit ional lesions inv olv ing t he lef t lat eral segment and c audat e lobe.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1848

12 - Liver F igure 12- 40 Dif f use hepat oc ellular c arc inoma w it h port al v ein t hrombosis.

Art erial phase CT image (A) show s int ense het erogeneous enhanc ement of t he lef t hepat ic lobe w it h mult iple smaller t umor nodules inv olv ing t he right lobe. Port al v enous phase image (B) show s enlargement and hy poat t enuat ion of t he ent ire lef t hepat ic lobe and ant erior segment of t he right lobe f rom t he dif f usely inf ilt rat ing t umor. T he expanded lef t port al v ein (ar r ow ) is f illed w it h t umor t hrombus.

F igure 12- 41 Hepat oc ellular c arc inoma in a pat ient w it hout c irrhosis. Cont rast - enhanc ed CT image demonst rat es a large v asc ular mass w it h a large area of c ent ral nec rosis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1849

12 - Liver F igure 12- 42 Enc apsulat ed hepat oc ellular c arc inoma. T 1- w eight ed MR image show s a hy perint ense mass (ar r ow ) w it h a hy point ense c apsule.

A c ommon int ernal f eat ure of HCC is t he presenc e of int rat umoral sept a, w hic h div ide t he mass int o c ompart ment s of v ariable signal int ensit y (332,347). T he sept a are t hinner t han t he t umor c apsule and are hy point ense on bot h T 1w eight ed and T 2- w eight ed images. A c ent ral sc ar, if present , is low in signal int ensit y on T 1- w eight ed images but may be eit her low or high in signal int ensit y on T 2- w eight ed images (696,866). T he presenc e of int rat umoral sept a or a c ent ral sc ar is not spec if ic f or HCC but also c an be seen w it h hepat oc ellular adenoma, F NH, or giant c av ernous hemangioma (696). Dy namic c ont rast - enhanc ed MRI is c apable of demonst rat ing HCCs not show n by unenhanc ed MRI (373). Af t er administ rat ion of gadolinium- c helat e, w elldef ined HCCs c harac t erist ic ally show peak c ont rast enhanc ement f rom 10 sec onds t o 2 minut es af t er injec t ion, w it h absent or minimal delay ed enhanc ement (599,895). Most bec ome isoint ense during t he port al v enous phase and isoint ense or hy point ense during t he equilibrium phase. Ac quisit ion of t hree suc c essiv e early dy namic post c ont rast MR imaging sequenc es is helpf ul t o c ompensat e f or indiv idual v ariat ions of c irc ulat ion t ime and t he v ariable t umor v asc ularit y of small hepat oc ellular c arc inomas (907). An enhanc ed t umor c apsule of t en c an be ident if ied on delay ed equilibrium phase images (F ig. 12- 43). T he c ont rast enhanc ement w ashout of HCC result ing in delay ed hy point ensit y (F ig. 12- 44) is helpf ul in dist inguishing HCC f rom hemangioma, w hic h show s persist ent enhanc ement similar t o t he blood pool on delay ed images (599,895) and f rom art erioport al shunt s and ot her “ pseudolesions,” w hic h hav e t he same signal int ensit y as liv er parenc hy ma on delay ed images. T he degree of enhanc ement of HCC is relat ed t o art erial hy perv asc ularit y and enlargement of sinusoidal spac es, bot h of w hic h result in great er c ont rast enhanc ement and are assoc iat ed w it h higher grade t umors (886). A peripheral halo of delay ed enhanc ement , c orresponding t o f ibrous c apsular st ruc t ures, c an be ident if ied in 43% t o 55% of pat ient s (see F ig. 12- 43) (599,895). HCC may show enhanc ement on delay ed images af t er administ rat ion of Mn- DPDP (561,681), Gd- BOPT A (486), and Gd- EOBDT PA (294). How ev er, suc h enhanc ement is not spec if ic f or HCC and c an be seen w it h ot her primary hepat oc ellular t umors, suc h as F NH and adenoma, and unc ommonly w it h hepat ic met ast ases (681). Gd- BOPT A may be usef ul in c harac t erizing HCC based on rapid enhanc ement during t he art erial phase and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1850

12 - Liver demonst rat ion of a double ring at t he periphery of w ell- dif f erent iat ed HCCs (842).

Det ec t ion of small HCCs in pat ient s w it h c irrhosis is dif f ic ult , ev en w it h st at eof - t he- art CT and MRI t ec hniques. In one st udy unenhanc ed, art erial- phase, and port al v enous phase helic al CT demonst rat ed only 44% of HCC nodules and 68% of pat ient s w it h HCC (638). In t hat st udy , only 37% of nodules and 59% of pat ient s w it h HCC w ere ident if ied prospec t iv ely . In anot her st udy , art erialphase, port al v enous- phase, and delay ed- phase helic al CT demonst rat ed 71% of HCC nodules and 80% of pat ient s w it h HCC (460). Comparat iv e st udies hav e f ound dy namic gadolinium- enhanc ed MRI t o be slight ly superior t o dual- phase helic al CT f or det ec t ing HCC in pat ient s w it h c hronic liv er disease (606,888). A limit at ion of noninv asiv e imaging t est s is poor det ec t ion of small sat ellit e nodules (678). CT perf ormed 1 t o 4 w eeks af t er int ra- art erial injec t ion of iodized oil, w hic h is ret ained w it hin hy perv asc ular hepat ic neoplasms, is c apable of demonst rat ing small HCCs not det ec t ed by noninv asiv e t ec hniques (568,795,908). How ev er, t his t ec hnique may be unsuc c essf ul in demonst rat ing hy pov asc ular lesions (899). Comput ed t omography art erial port ography (CT AP) is generally c onsidered t he most sensit iv e pre- operat iv e imaging t est f or det ec t ing small HCCs (506,527,765) despit e t he f ac t t hat CT AP f ails t o demonst rat e 50% of sat ellit e nodules (527). How ev er, t riple- (art erial, port al v enous, and delay ed) phase helic al CT w as f ound t o be as sensit iv e as c ombined CT AP and CT HA f or pre- operat iv e det ec t ion of HCC (336). Moreov er, in t hat st udy CT AP and CT HA had an unac c ept ably high f alse posit iv e rat e. In pat ient s w it h c hronic liv er disease, HCC usually dev elops in a mult ist ep proc ess, beginning w it h a benign regenerat iv e nodule and passing t hrough st ages of dy splasia and early malignant c hange t o f rank c arc inoma (116,201,296,707,807). A regenerat iv e nodule is a w ell- def ined region of parenc hy ma t hat has enlarged in response t o nec rosis, alt ered c irc ulat ion, or ot her st imuli (306). Ac c ording t o t he c lassif ic at ion agreed on in 1994 by t he Int ernat ional Working Part y of t he World Congress of Gast roent erology (306), t he next st age in hepat oc ellular c arc inogenesis is dev elopment of a dy splast ic nodule, w hic h is def ined as a nodular region of hepat oc y t es at least 1 mm in diamet er c ont aining dy splasia but no def init e hist ologic c rit eria of malignanc y . Dy splast ic nodules are c lassif ied as low grade or high grade P.867 depending on t he degree of c ellular at y pia (low grade—mild at y pia; high grade—moderat e or sev ere at y pia). Ac c ording t o t his sc heme, a f oc us of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1851

12 - Liver hepat oc ellular c arc inoma t hen dev elops w it hin a dy splast ic nodule and begins t o grow . A small hepat oc ellular c arc inoma is def ined as one measuring less t han 2 c m in diamet er. Bec ause t his proc ess c onst it ut es a c ont inuous

spec t rum of abnormalit y , dif f erent iat ing small HCCs f rom nonmalignant nodular masses in t he c irrhot ic liv er is an ext remely dif f ic ult imaging problem. Nev ert heless, t his dist inc t ion is c rit ic al bec ause early liv er t ransplant at ion c urrent ly prov ides t he only opport unit y f or c ure in pat ient s w it h HCC and c irrhosis (277), and t arget ed t herapies suc h as t umor ablat ion are most ef f ec t iv e w hen t he lesion is small. MRI may be helpf ul in making t his dist inc t ion (119,319,508,559,602). Regenerat iv e nodules appear hy point ense, isoint ense, or hy perint ense on T 1- w eight ed images and isoint ense or hy point ense on T 2- w eight ed images (F ig. 12- 45). T he hy point ensit y is relat ed t o iron c ont ained w it hin some of t he nodules; henc e t hey are ref erred t o as siderot ic nodules. Dy splast ic nodules are generally hy point ense or hy perint ense on T 1- w eight ed images and isoint ense or hy point ense on T 2w eight ed images (F ig. 12- 46) (119,122,174,508). P.868 As not ed prev iously , HCC usually is isoint ense or hy perint ense on T 2- w eight ed images (177,347,874) but c an also be hy point ense (174,373). Bec ause t he signal int ensit y c harac t erist ic s of dy splast ic nodules ov erlap signif ic ant ly w it h t hose of small HCCs, most inv est igat ors hav e c onc luded t hat dy splast ic nodules and HCC c annot be dist inguished ac c urat ely on unenhanc ed MRI (122,174,178,305,543,606,887). A f eat ure t hat c an be helpf ul in dist inguishing HCC f rom a dy splast ic nodule at unenhanc ed MRI is t he f ac t t hat dy splast ic nodules are rarely hy perint ense on T 2- w eight ed images (559,602).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1852

12 - Liver

F igure 12- 43 Hepat oc ellular c arc inoma. Art erial phase gadolinium- enhanc ed T 1- w eight ed spoiled gradient ec ho image (A) show s a large het erogeneously enhanc ing hepat ic mass. A hy point ense f ibrous c apsule (ar r ow s) surrounds t he lesion. Delay ed post c ont rast c oronal image (B) demonst rat es enhanc ement of t he t umor c apsule (ar r ow heads). Not e mult iple addit ional enc apsulat ed lesions.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1853

12 - Liver

F igure 12- 44 Small hepat oc ellular c arc inomas w it h c ont rast enhanc ement “ w ashout .” Art erial phase gadolinium- enhanc ed T 1- w eight ed spoiled gradient ec ho image w it h f at suppression (A) show s t w o small hy perint ense lesions (ar r ow s) at t he dome of t he liv er. Port al v enous phase image (B) at t he same lev el show s t hat t he more ant erior lesion has bec ome hy point ense and is surrounded by an enhannc ing c apsule (ar r ow head).

Bec ause t he main blood suppy t o dy splast ic nodules is f rom t he port al v enous sy st em and t hat t o HCCs f rom t he hepat ic art erial sy st em (270,510), HCC of t en c an be dist inguished f rom dy splast ic nodule at dy namic c ont rast enhanc ed CT or Gd- enhanc ed MRI on t he basis of ident if ic at ion of hepat ic art erial enhanc ement (428). Dy splast ic nodules generally do not enhanc e during t he hepat ic art erial phase. Nev ert heless, dy splast ic nodules c ont ain v ary ing amount s of art erial blood supply (270,459,510,684), and a small perc ent age of t hem may demonst rat e hepat ic art erial phase enhanc ement (341,404), possibly on t he basis of neoplast ic angiogenesis (627). Bot h CT and MRI using unenhanc ed and ext rac ellular c ont rast agent - enhanc ed imaging are relat iv ely insensit iv e f or det ec t ion of dy splast ic nodules and small HCCs in c irrhot ic liv ers. St udies w it h explant c orrelat ion hav e demonst rat ed sensit iv it ies of 33% t o 77% and 15% t o 42% f or det ec t ion of HCC and dy splast ic nodules, respec t iv ely (89,152,406,407,457,460,680). Use of doublec ont rast MRI, c onsist ing of pre- and post c ont rast imaging w it h superparamagnet ic iron oxide (SPIO) f ollow ed by dy namic gadolinium- enhanc ed imaging, may improv e det ec t ion of HCC in pat ient s w it h c irrhosis (50,850). In one st udy , sensit iv it y of double- c ont rast MRI f or det ec t ion of HCCs larger t han 1 c m w as 92%, but sensit iv it y f or lesions less t han or equal t o 1 c m remained limit ed at 38% (ov erall sensit iv it y , 76%) (50).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1854

12 - Liver Use of SPIO- enhanc ed MR imaging alone f or det ec t ion of HCC has had mixed result s. One st udy show ed t hat SPIO- enhanc ed MRI w as equiv alent t o

c ombined CT HA and CT AP (124), and anot her show ed t hat SPIO- enhanc ed MRI w as superior t o t riple- phase CT (359) f or det ec t ion of HCC. How ev er, in sev eral ot her st udies SPIO- enhanc ed imaging w as f ound t o be inf erior t o ext rac ellular gadolinium- c helat e- enhanc ed (631,798) and Gd- BOPT A- enhanc ed MRI (387) f or det ec t ion of HCC. A possible w ay of c harac t erizing nodular hepat ic lesions in pat ient s w it h c irrhosis is by c orrelat ing t he result s of helic al CT and SPIO- enhanc ed MRI (461). F or example, a nodule t hat c an be ident if ied on helic al CT bec ause of enhanc ement dif f erent f rom t he hepat ic parenc hy ma but t hat is not ev ident on SPIO- enhanc ed MRI likely is a dy splast ic nodule or a w ell- dif f erent iat ed HCC. A nodule t hat is hy poat t enuat ing on art erial, port al v enous, and delay ed phase CT and has high signal int ensit y on SPIO- enhanc ed MRI likely is a moderat ely or poorly dif f erent iat ed HCC (461). T he signif ic anc e of iron in regenerat iv e nodules is unc lear. One st udy f ound t hat t he f requenc y of HCC in pat ient s w it h iron deposit ion in regenerat iv e nodules (siderot ic nodules) w as signif ic ant ly higher t han in pat ient s w it hout iron in regenerat iv e nodules (326). How ev er, in anot her st udy t here w as no signif ic ant inc reased f requenc y of HCC or dy splast ic nodules in pat ient s w it h pat hologic ally prov ed siderot ic nodules (405). A mac rosc opic f oc us of hepat oc ellular c arc inoma w it hin a siderot ic regenerat iv e nodule c an somet imes be ident if ied as a small nodule w it hin a larger nodule (537,874). On gradient P.869 ec ho images, t he “ nodule- w it hin- nodule” appearanc e c onsist s of a low int ensit y large nodule c ont aining one or t w o f oc i t hat are isoint ense t o liv er parenc hy ma. T he most c ommon appearanc e on T 2- w eight ed images is t hat of a hy perint ense f oc us w it hin a hy point ense nodule (F ig. 12- 47).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1855

12 - Liver

F igure 12- 45 Regenerat iv e nodules. T 2- w eight ed (A), art erial phase (B), and port al v enous phase (C ) gadolinium- enhanc ed T 1- w eight ed MR images show mult iple hy point ense nodules t hroughout t he liv er.

An addit ional c hallenge in t he c harac t erizat ion of nodular hepat ic lesions is dist inguishing HCC f rom ot her benign c auses of hepat ic art erial phase enhanc ement at CT and MRI, inc luding t ransient hepat ic at t enuat ion dif f erenc e, art erioport al shunt s, hepat ic peliosis, f ibrosis, and ot her poorly underst ood c auses (14,71,511,596,900,901,906). Some of t hese benign areas of art erial phase enhanc ement c an be round or ov al in shape and simulat e t he appearanc e of HCC. T he best c urrent approac h t o t hese nodular enhanc ing lesions is imaging f ollow up. Int erv al grow t h is highly predic t iv e of HCC,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1856

12 - Liver

w hereas pseudolesions usually disappear, dec rease in size, or show no int erv al grow t h (341,731).

Fibrolamellar Hepatocellular Carcinoma F ibrolamellar hepat oc ellular c arc inoma is a hist ologic subt y pe of hepat oc ellular c arc inoma t hat oc c urs in y ounger pat ient s w it hout underly ing liv er disease (73,221,300). P.870 Whereas t he usual HCC oc c urs more c ommonly in men, f ibrolamellar HCC has no sex predilec t ion. Hist ologic ally , t he t umor c onsist s of malignant eosinophilic hepat oc y t es t hat are separat ed int o c ords by t hin, mult ilamellat ed, f ibrous st rands (653). Serum О±- f et oprot ein lev els are usually normal. Pat ient s w it h f ibrolamellar HCC hav e a bet t er prognosis t han t hose w it h t he usual t y pe of HCC, despit e t he f ac t t hat f ibrolamellar HCC is usually v ery large, f requent ly show s aggressiv e loc al inv asion, and is of t en assoc iat ed w it h nodal and dist ant met ast ases (301). Aggressiv e surgic al resec t ion may be helpf ul t o c ont rol t he t umor and t o prolong surv iv al in appropriat ely selec t ed pat ient s (301). T he most rec ent ly report ed 5- y ear surv iv al rat e f or a large series of pat ient s w it h f ibrolamellar HCC is 66% (642).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1857

12 - Liver F igure 12- 46 Dy splast ic nodule in a pat ient w it h c irrhosis. Prec onst rast T 1w eight ed spoiled gradient ec ho MR image w it h f at suppression (A) show s a w ell- def ined hy perint ense nodule (ar r ow ) in t he lef t hepat ic lobe. T he nodule (ar r ow ) is hy point ense on a T 2- w eight ed image (B). On an art erial phase

gadolinium- enhanc ed T 1- w eight ed image (C ), t he lesion enhanc es t o t he same degree as t he surrounding liv er.

F igure 12- 47 Hepat oc ellular c arc inoma arising w it hin a dy splast ic nodule. Unenhanc ed T 2- w eight ed MR image show s a slight ly hy point ense round hepat ic mass (ar r ow ) t hat c ont ains a c ent ral area of hy perint ensit y , giv ing t he mass a “ nodule- w it hin- nodule” appearanc e. Court esy of Hero Hussain, MD.

On CT , f ibrolamellar HCC appears as a large, w ell- def ined het erogeneously enhanc ing mass (F ig. 12- 48) t hat f requent ly has surf ac e lobulat ions (73,300,522). A c ent ral sc ar, of t en w it h c alc if ic at ion, c an be ident if ied in approximat ely half of pat ient s (F ig. 12- 49) (73,221,300,522). Delay ed enhanc ement of t he sc ar may be ident if ied in 25% of c ases on bot h CT and MRI (522). On MRI, f ibrolamellar HCC is usually hy point ense t o liv er on T 1w eight ed images P.871 and hy perint ense w it h het erogeneous signal int ensit y on T 2- w eight ed images (522,808). T he c ent ral sc ar is hy point ense t o surrounding t umor and liv er on bot h T 1- and T 2- w eight ed images (F ig. 12- 50) (300). On dy namic gadoliniumenhanc ed images t he mass enhanc es het erogeneously w it h no enhanc ement of t he c ent ral sc ar (see F ig. 12- 50) (137). T he t umor most resembling

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1858

12 - Liver f ibrolamellar HCC is F NH. Bot h lesions t end t o oc c ur in y oung pat ient s, and bot h of t en c ont ain c ent ral sc ars. T he c harac t erist ic s of t he sc ar c an be helpf ul in dif f erent iat ing t hese t umors. T he sc ar in f ibrolamellar HCC is f requent ly c alc if ied, w hereas t he sc ar in F NH is rarely c alc if ied (1.4% of lesions) (96). At MRI t he sc ar in F NH is hy perint ense on T 2- w eight ed images and show s delay ed enhanc ement (see F ig. 12- 22), w hereas t hat in f ibrolamellar HCC is hy point ense on T 2- w eight ed images w it h lac k of delay ed enhanc ement in most c ases (see F ig. 12- 50).

F igure 12- 48 F ibrolamellar hepat oc ellular c arc inoma. Lat e hepat ic art erial phase c ont rast - enhanc ed CT image show s a large het erogeneously enhanc ing mass in t he lef t hepat ic lobe. Not e t he t ransient hepat ic at t enuat ion dif f erenc e (T HAD) surrounding t he lesion. Court esy of Demet rios Papadat os, MD.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1859

12 - Liver

F igure 12- 49 F ibrolamellar hepat oc ellular c arc inoma. Unenhanc ed CT image show s a large, slight ly hy poat t enuat ing lef t hepat ic lobe mass w it h a c alc if ied c ent ral sc ar (ar r ow ).

Intrahepatic Cholangiocarcinoma Int rahepat ic c holangioc arc inoma is an adenoc arc inoma t hat arises f rom t he epit helium of small int rahepat ic bile duc t s. Alt hough it is t he sec ond most c ommon primary malignant hepat ic neoplasm, it is muc h less c ommon t han hepat oc ellular c arc inoma, ac c ount ing f or only approximat ely 10% of all primary hepat ic malignanc ies (141). Predisposing c ondit ions inc lude primary sc lerosing c holangit is, Clonor c his sinensis inf est at ion, and t horium dioxide (T horot rast ) exposure. In addit ion, v arious c ongenit al biliary anomalies hav e been assoc iat ed w it h inc reased risk of c holangioc arc inoma (880). How ev er, most pat ient s hav e no underly ing hepat ic parenc hy mal disease (880). Grossly , c holangioc arc inoma is a f irm hy pov asc ular t umor w it h predominant ly f ibrous st roma (653). Hist ologic ally , it is usually a w ell- dif f erent iat ed sc lerosing adenoc arc inoma w it h abundant desmoplasia (880). Biliary duc t al dilat ion peripheral t o t he mass is a c ommon f inding (120,190,287), and port al v enous enc asement by c holangioc arc inoma may lead t o hepat ic segment al or lobar at rophy (F ig. 12- 51) (190,762,793,885). T he c linic al present at ion depends on t he loc at ion of t he mass. Peripheral masses c ause pain and c onst it ut ional sy mpt oms lat e in t heir c ourse, w hereas c ent rally loc at ed (hilar) masses t end t o present earlier w it h painless obst ruc t iv e jaundic e (287).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1860

12 - Liver

T he usual CT appearanc e is t hat of a hy poat t enuat ing mass of t en w it h lobular margins t hat show s mild early peripheral enhanc ement , w it h gradual c ent ripet al enhanc ement and pooling of c ont rast mat erial on delay ed images (F ig. 12- 52) (287,463,760,761) (see F ig. 12- 44). T he c harac t erist ic enhanc ement pat t ern is due t o t he large amount of int erst it ial spac e in t he t umor's ext ensiv e f ibrous st roma. Slow dif f usion of c ont rast medium f rom t he v asc ular t o t he int erst it ial spac e result s in delay ed and prolonged enhanc ement of t he t umor (86,317), w hic h is best seen approximat ely 10 t o 20 minut es af t er c ont rast medium administ rat ion (375). T he degree of c ont rast medium ret ent ion, how ev er, does not alw ay s c orrelat e w it h t he f ibrous c ont ent of t he t umor (416). Sat ellit e nodules are f requent ly present (F ig. 1253) (190,386,475,689), and biliary duc t al dilat ion peripheral t o t he t umor is a c ommon f eat ure (see F ig. 12- 53). Peripheral masses are somet imes assoc iat ed w it h c apsular ret rac t ion (386,760,762). Bec ause t hese lesions f requent ly produc e muc in, c alc if ic at ion is present in a small perc ent age of c ases (287,689). F if t y perc ent of int rahepat ic c holangioc arc inomas imaged by c ont rast - enhanc ed CT are assoc iat ed w it h t ransient segment al or lobar hepat ic at t enuat ion inc rease (see F ig. 12- 53), w hic h is P.872 t hought t o be due t o inc reased hepat ic art erial perf usion sec ondary t o port al v enous inv asion by t he t umor (885).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1861

12 - Liver F igure 12- 50 F ibrolamellar hepat oc ellular c arc inoma. T 2- w eight ed MR image w it h f at suppression (A) show s a large mass (ar r ow s) in t he medial segment of t he lef t hepat ic lobe. T he mass is minimally hy perint ense and c ont ains a hy point ense c ent ral sc ar (ar r ow head). Art erial phase T 1- w eight ed image (B) demonst rat es int ense het erogeneous enhanc ement of t he mass, exc ept f or t he c ent ral sc ar. T he sc ar remains unenhanc ed on a delay ed post c ont rast image (C ).

F igure 12- 51 Int rahepat ic c holangioc arc inoma. Art erial phase T 1- w eight ed MR image (A) show s a small hy point ense lef t lobe mass (ar r ow ) w it h mild peripheral enhanc ement . T he mass has c aused biliary duc t al dilat ion (ar r ow head) and segment al hepat ic at rophy (open ar r ow ). On t he delay ed post c ont rast image (B) t he mass is more c onspic uous bec ause of it s hy perint ensit y c aused by pooling of c ont rast medium w it hin it .

On MRI, c holangioc arc inoma is hy point ense relat iv e t o liv er parenc hy ma on T 1w eight ed images. On T 2- w eight ed images it is usually hy perint ense (190,762) but may be isoint ense in some c ases (835). T he enhanc ement pat t ern is similar t o t hat seen on CT , c onsist ing of mild t o moderat e rim enhanc ement w it h progressiv e c ent ripet al f ill- in of c ont rast mat erial on delay ed images (190,263,762) (F igs. 12- 51 and 12- 54). A c ent ral sc ar, w hic h is hy point ense on P.873 P.874 T 1- w eight ed images and hy point ense, isoint ense, or hy perint ense on T 2w eight ed images, c an be ident if ied in more t han half of c ases (190,762). T he sc ar may show enhanc ement on delay ed post c ont rast images (762).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1862

12 - Liver

F igure 12- 52 Int rahepat ic c holangioc arc inoma. Port al v enous phase c ont rast enhanc ed CT image (A) show s a large c ent ral hepat ic mass w it h mild peripheral enhanc ement . A 30- minut e delay ed post c ont rast image (B) show s persist ent hy perat t enuat ion of a large port ion of t he mass due t o pooling of c ont rast medium w it hin t he lesion.

F igure 12- 53 Int rahepat ic c holangioc arc inoma. Lat e hepat ic art erial phase image (A) show s a large lobulat ed c ent ral hepat ic mass w it h peripheral

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1863

12 - Liver enhanc ement . A slight ly more c ephalad image (B) show s dilat ion of bile duc t s peripheral t o t he mass and t ransient hepat ic at t enuat ion dif f erenc e (T HAD) w it h dif f usely inc reased at t enuat ion of t he right hepat ic lobe. A c oronal 3Dv olume rendered image (C ) show s a sat ellit e lesion (ar r ow ) near t he dome of t he liv er.

F igure 12- 54 Int rahepat ic c holangioc arc inoma. Art erial phase T 1- w eight ed gadolinium- enhanc ed MR image (A) show s a large hepat ic mass w it h a rim of peripheral enhanc ement . Port al v enous phase image (B) show s mild inw ard progression of t he enhanc ement . Delay ed phase image (C ) show s c ont inued c ent ripet al progression of enhanc ement w it h pooling of c ont rast medium w it hin t he lesion. Not e t he t hin hy point ense peripheral rim (ar r ow heads) t hat c orresponds t o t he port ion of t he lesion t hat w as enhanc ed on t he art erial phase image.

Metastases T he liv er is sec ond in f requenc y only t o t he lungs as a sit e of inv olv ement by dist ant met ast ases. T heref ore, assessment of t he liv er is a c rit ic al part of t he c linic al ev aluat ion of most c anc er pat ient s. Unf ort unat ely , t he imaging

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1864

12 - Liver appearanc e of hepat ic met ast ases is quit e v ariable and nonspec if ic , ov erlapping w it h t hat of primary malignant hepat ic lesions and benign hepat ic lesions. T he CT and MRI appearanc e of met ast ases depends on a number of f ac t ors inc luding lesion hist ology , v asc ularit y , and size as w ell as t he presenc e of nec rosis, f ibrosis, c alc if ic at ion, or hemorrhage w it hin t he mass. It is import ant t o keep in mind t hat small benign hepat ic masses are v ery c ommon. In a pat ient w it hout a know n malignanc y , t he likelihood of a small

(less t han or equal t o 10 mm) mass being a met ast asis is v ery low (343). Ev en in a pat ient w it h know n malignant disease, t he c hanc e of suc h a lesion being malignant is less t han 20% (718) (378). One st udy has demonst rat ed t hat in pat ient s w it h c olorec t al and gast ric c anc er, t he probabilit y of one or more hy poat t enuat ing liv er lesions less t han or equal t o 15 mm in diamet er being malignant in t he absenc e of ev idenc e of larger met ast ases is less t han 3% (337). Anot her st udy demonst rat ed t hat among pat ient s w it h breast c anc er w ho had hepat ic lesions c onsidered t oo small t o c harac t erize but no def init e liv er met ast ases at init ial CT , in 93% t o 96% of t he w omen t he lesions w ere benign (378). Alt hough t he presenc e of mult iple hepat ic masses is suggest iv e of met ast at ic disease, a v ariet y of benign hepat ic lesions c an be mult iple and should be c onsidered in t he dif f erent ial diagnosis. T hese lesions inc lude c y st s, hemangiomas, biliary hamart omas, and f ungal absc esses. In a pat ient w it h c hronic liv er disease, mult ic ent ric hepat oc ellular c arc inoma should be c onsidered.

F igure 12- 55 Met ast ases f rom c olon c arc inoma. Port al v enous phase c ont rast - enhanc ed CT image show s mult iple hy poat t enuat ing lesions w it h mild

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1865

12 - Liver c ont inuous rim enhanc ement .

P.875 Most met ast ases are hy pov asc ular and appear hy poat t enuat ing relat iv e t o t he liv er parenc hy ma on port al v enous phase CT images (F ig. 12- 55). T hus f or det ec t ion of t he large majorit y of hepat ic met ast ases, a single post c ont rast image dat aset t imed at t he peak of hepat ic parenc hy mal enhanc ement is suf f ic ient . In one st udy t he ov erall sensit iv it y of port al v enous phase helic al CT f or demonst rat ing hepat ic neoplasms w as 81% and t hat f or lesions larger t han 1 c m w as 91% (411). When art erial phase imaging is perf ormed, t he most c ommon enhanc ement pat t ern of met ast ases is c ont inuous ring- like enhanc ement at t he periphery of t he lesion (588). Hy perv asc ular met ast ases may bec ome isoat t enuat ing and t hus dif f ic ult t o det ec t during t he port al v enous phase of enhanc ement (77,169) (F igs. 12- 56 and 12- 57). Suc h t umors inc lude renal c ell c arc inoma, c arc inoid t umor, malignant adrenal t umors, t hy roid c arc inoma, panc reat ic islet c ell t umors, neuroendoc rine t umors, sarc omas, and melanoma. Met ast ases f rom suc h t umors are of t en more easily ident if ied during t he hepat ic art erial phase of enhanc ement w hen t hey appear hy perat t enuat ing relat iv e t o t he poorly enhanc ed liv er parenc hy ma (57,283,531,613) (see F igs. 12- 56 and 12- 57). T heref ore, pat ient s w it h a know n v asc ular primary malignanc y should be ev aluat ed w it h mult iphase helic al CT , w it h images ac quired during bot h t he lat e hepat ic art erial and t he port al v enous phase of enhanc ement . Alt hough hepat ic met ast ases in pat ient s w it h breast c anc er c an be hy perv asc ular, one st udy f ound t hat none of 84 CT examinat ions of breast c anc er pat ient s w as c onv ert ed f rom negat iv e t o posit iv e by addit ion of hepat ic art erial phase imaging (215). In anot her st udy , w hic h inc luded 300 breast c anc er pat ient s, 2% t o 4% of lesions w ere ident if ied only on hepat ic art erial phase or prec ont rast images, but all of t hese lesions w ere eit her f alse posit iv e f indings or w ere seen in c onjunc t ion w it h addit ional met ast ases on t he port al v enous phase images (729). T heref ore, t he inv est igat ors of t hese st udies did not rec ommend rout ine mult iphase hepat ic imaging f or breast c anc er pat ient s. If helic al CT is not av ailable, prec ont rast images of t he liv er are rec ommended (77,613). Prec ont rast images are also usef ul t o ident if y c alc if ied (F ig. 12- 58) and hemorrhagic (F ig. 12- 59) met ast ases. Calc if ic at ion oc c urs most c ommonly in met ast ases f rom muc inous c olon c arc inoma (see F ig. 12- 58) but c an be seen w it h ot her primary t umors inc luding gast ric , ov arian, breast , t hy roid, lung,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1866

12 - Liver renal, c arc inoid, and melanoma in addit ion t o a v ariet y of less c ommon neoplasms (47,196,520,710,785).

F igure 12- 56 Hy perv asc ular met ast ases f rom a panc reat ic gluc agonoma. Art erial phase CT image (A) show s mult iple hy perat t enuat ing hepat ic masses t hat bec ome isoat t enuat ing on t he port al v enous phase image (B) and are no longer ident if iable.

P.876 An unc ommon manif est at ion of some liv er met ast ases is ret rac t ion of t he adjac ent liv er c apsule. It is seen in only approximat ely 2% of pat ient s and has been report ed w it h breast , c olon, lung, and c arc inoid t umor met ast ases (199,709,758). In breast c anc er pat ient s, c apsular ret rac t ion is assoc iat ed w it h relat iv ely large met ast ases and w it h c hange in size (eit her inc rease or dec rease) of t he met ast asis ov er t ime (199). Oc c asionally , met ast ases may be c y st ic and hav e an appearanc e similar t o t hat of a benign c y st . T hey usually c an be dist inguished f rom a benign c y st , how ev er, by t heir disc ernible w all and t he presenc es of mural nodularit y (F ig. 12- 60).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1867

12 - Liver F igure 12- 57 Hy perv asc ular hepat ic met ast ases f rom c arc inoid t umor. T w o small hy perat t enuat ing masses (ar r ow s) demonst rat ed during t he hepat ic art erial phase of enhanc ement (A) bec ome isoat t enuat ing and are no longer v isible during t he port al v enous enhanc ement phase (B).

An adv ant age of mult idet ec t or- row CT (MDCT ) is t hat it prov ides t he c apabilit y of imaging t he liv er w it h v ery t hin sec t ions. T w o st udies hav e show n t hat more liv er lesions c an be det ec t ed w it h 2.5- mm slic e t hic kness t han w it h 5.0- mm slic e t hic kness (257,855). In one of t hese st udies, how ev er, t he det ec t ion rat e f or met ast ases w as equiv alent w it h bot h t he 2.5- mm and 5.0- mm t hic k images, suggest ing t hat most of t he addit ional lesions ident if ied w it h t he t hinner slic e t hic kness are benign lesions (257). F urt her st udy is needed t o det ermine t he opt imum sec t ion t hic kness f or det ec t ing small liv er lesions w it h MDCT .

F igure 12- 58 Calc if ied hepat ic met ast ases in a pat ient w it h muc inous adenoc arc inoma of t he c olon.

At MRI met ast ases are generally hy point ense on T 1- w eight ed images and hy perint ense on T 2- w eight ed images. Exc ept ions inc lude hemorrhagic lesions and met ast ases f rom melanoma, w hic h may hav e high T 1 signal int ensit y (371,430,656) (see F ig. 12- 50). Met ast ases are of t en het erogeneous in signal int ensit y w it h indist inc t margins. F if t een t o t w ent y - sev en perc ent hav e a c ent ral area of hy perint ensit y (“ t arget ” sign) on T 2- w eight ed images, w hic h c orresponds t o c ent ral nec rosis (617,876) (F ig. 12- 61). Approximat ely half of met ast ases f rom c olorec t al c arc inoma demonst rat e c ent ral areas t hat are low er in signal int ensit y relat iv e t o t he higher int ensit y t umor edge on T 2w eight ed images (“ halo” sign). T he c ent ral low er signal int ensit y c orresponds pat hologic ally t o desmoplasia and c oagulat iv e nec rosis, w hereas

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1868

12 - Liver t he higher signal int ensit y rim c orresponds t o v iable t umor c ells at t he

periphery of t he t umor (617). In approximat ely 25% of c olorec t al met ast ases a t hin rim of low signal int ensit y may be ident if ied, c orresponding t o a c ombinat ion of c ompressed hepat ic parenc hy ma and sinusoids, hepat oc ellular at rophy , and f ibrosis (617). Alt hough t he signal int ensit y on T 2- w eight ed images of most met ast ases is less t han t hat of hemangiomas and c y st s, 5% t o 10% of met ast ases may hav e signal P.877 int ensit y c harac t erist ic s ov erlapping t hose of benign lesions (876). In suc h c ases, gadolinium- enhanc ed imaging is usef ul f or lesion c harac t erizat ion.

F igure 12- 59 Hemorrhagic met ast ases. Prec ont rast CT image (A) of a pat ient w it h met ast at ic melanoma show s sev eral small, high at t enuat ion masses near t he dome of t he liv er. Art erial phase c ont rast - enhanc ed image (B) show s minimal enhanc ement of t hese lesions and demonst rat es mult iple addit ional nonhemorrhagic lesions t hat w ere not v isible on t he prec ont rast image.

On dy namic gadolinium- enhanc ed MRI, met ast ases demonst rat e enhanc ement c harac t erist ic s similar t o t hose desc ribed f or CT . Hy pov asc ular lesions are seen as hy point ense masses t hat may show rim enhanc ement during t he hepat ic art erial phase (146). Some met ast ases also demonst rat e perilesional enhanc ement on early gadolinium- enhanc ed images (F ig. 12- 62), w hic h c orrelat es w it h hist opat hologic hepat ic parenc hy mal c hanges, inc luding perit umoral desmoplast ic reac t ion, inf lammat ory c ell inf ilt rat ion, and v asc ular prolif erat ion (724). Hy perv asc ular lesions usually are seen as hy perint ense masses during t he hepat ic art erial phase, but t hey may bec ome isoint ense and t hus imperc ept ible during t he port al v enous phase. On delay ed (5 t o 10 minut es) images, approximat ely one quart er of met ast ases demonst rat e a rim

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1869

12 - Liver t hat is hy point ense c ompared w it h t he c ent er of t he lesion (“ peripheral w ashout ” sign) (F ig. 12- 63), w hic h is c onsidered a spec if ic sign of malignanc y (482). Alt hough it is seen w it h hy pov asc ular and hy perv asc ular

lesions, peripheral w ashout is more c onspic uous and observ ed more f requent ly w it h hy perv asc ular met ast ases (146).

F igure 12- 60 Cy st ic met ast asis. Cont rast - enhanc ed CT image show s a large c y st ic hepat ic mass in a pat ient w it h c olon c arc inoma. Not e t hat t he mass has a t hin w all and a mural nodule (ar r ow ), w hic h dist inguish it f rom a simple hepat ic c y st .

Sev eral st udies hav e show n inc reased det ec t ion of liv er lesions w it h gadolinium- enhanc ed MR imaging c ompared w it h unenhanc ed MRI (55,140,764). In one of t he st udies, unenhanc ed imaging demonst rat ed more lesions ov erall, but gadolinium- enhanc ed imaging demonst rat ed more nonc y st ic liv er lesions (140). Anot her st udy , how ev er, demonst rat ed no st at ist ic ally signif ic ant dif f erenc e bet w een unenhanc ed and gadolinium- c helat e enhanc ed MR imaging in dif f erent iat ing pat ient s w it h liv er met ast ases f rom t hose w it hout met ast ases (261). Nev ert heless, dy namic gadolinium- c helat e enhanc ed imaging is an int egral part of t he MR liv er imaging examinat ion f or det ec t ion of met ast ases and is part ic ularly usef ul in c harac t erizing hepat ic lesions t hat are ident if ied (260,482,822,865,887,895).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1870

12 - Liver

F igure 12- 61 Hepat ic met ast ases f rom c olon c arc inoma. Mult iple hepat ic masses are hy point ense on a T 1- w eight ed (A) and hy perint ense on a T 2w eight ed (B) image. On t he T 2- w eight ed image (B), t he masses hav e a c ent ral area of inc reased hy perint ensit y (“ t arget ” sign).

P.878 MRI and dy namic c ont rast - enhanc ed CT are c omparable (80% t o 90% sensit iv it y ) in t heir abilit y t o ident if y pat ient s w it h hepat ic met ast ases. Alt hough result s hav e v aried, most c omparat iv e st udies hav e show n MRI t o be somew hat more sensit iv e t han c ont rast - enhanc ed CT f or t he det ec t ion of indiv idual hepat ic met ast ases (151,606,673,698,720,773,830,861,910). In addit ion, superparamagnet ic iron oxide enhanc ed MRI has been show n t o be more sensit iv e t han dual- phase helic al CT f or hepat ic lesion det ec t ion (849). Comparisons bet w een st at e- of - t he- art MRI and c urrent ly av ailable MDCT hav e y et t o be perf ormed. Despit e t he slight superiorit y of MRI f or det ec t ing hepat ic met ast ases, CT remains t he imaging proc edure used most of t en f or sc reening c anc er pat ient s bec ause of it s w ider av ailabilit y , low er c ost , short er imaging t ime, and superiorit y f or det ec t ing ext rahepat ic disease. F or preoperat iv e st aging of hepat ic met ast ases, CT art erial port ography (CT AP) w as unt il rec ent ly c onsidered t o be t he most sensit iv e imaging met hod av ailable (273,574,757). Sev eral st udies, how ev er, hav e show n gadolinium- enhanc ed MRI or superparamagnet ic iron oxide enhanc ed MRI t o be as sensit iv e or more sensit iv e t han CT AP f or det ec t ing liv er met ast ases (38,722,726). In addit ion, alt hough one st udy of helic al CT f or pre- operat iv e st aging of liv er neoplasms show ed a sensit iv it y of only 69% t o 71% (356), ot her st udies hav e demonst rat ed result s t hat parallel t hose of CT AP (411,819,820). Consequent ly , noninv asiv e CT and MR imaging t ec hniques hav e largely

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1871

12 - Liver replac ed CT AP f or preoperat iv e st aging of pat ient s w it h c olorec t al c anc er met ast ases. MDCT angiography w it h v olumet ric 3D rendering also has been show n t o be an P.879 exc ellent t ec hnique f or planning int ra- art erial c hemot herapy pump plac ement in pat ient s w it h c olorec t al c anc er (362,704) and f or preoperat iv e ev aluat ion bef ore hepat ic resec t ion (703,776).

F igure 12- 62 Hepat ic met ast asis in a pat ient w it h breast c arc inoma. Early gadolinium- enhanc ed T 1- w eight ed MR image (A) show s a hy point ense hepat ic mass w it h a t hin rim of perilesional enhanc ement . Equilibrium phase image (B) demonst rat es a hy point ense rim at t he periphery of t he lesion.

F igure 12- 63 Hepat ic met ast asis show ing peripheral w ashout sign. A delay ed image obt ained 5 minut es af t er gadolinium administ rat ion demonst rat es a mass (ar r ow ) in w hic h t he periphery is hy point ense relat iv e t o t he c ent er.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1872

12 - Liver Rare Malignant Tumors Biliary c y st adenoc arc inoma is t he malignant c ount erpart of biliary c y st adenoma, w hic h is an unc ommon benign c y st ic neoplasm w it h demonst rat ed malignant pot ent ial (308,862). Bot h oc c ur predominant ly in middle- aged w omen, alt hough t he predominanc e is not as marked w it h t he malignant f orm (115,308,399). Grossly , biliary c y st adenoma and c y st adenoc arc inoma are large, c y st ic masses t hat are usually sept at ed but may be uniloc ular. T he c y st ic spac es c ont ain muc inous or serous f luid (141). Papillary exc resc enc es and mural or sept al nodules may be present , part ic ularly in t he malignant f orm. Cent rally loc at ed masses may c ause biliary

duc t al obst ruc t ion (82). Rarely , ext rahepat ic biliary c y st adenoma may simulat e a c holedoc hal c y st on imaging st udies (626).

F igure 12- 64 Biliary c y st adenoma. (A) Unenhanc ed c oronal T 2- w eight ed MR image show s a large homogeneously hy perint ense mass (M) arising f rom hepat ic segment IVb. Gadolinium- enhanc ed T 1- w eight ed image (B) demonst rat es a single sept at ion w it hin t he mass.

At CT , biliary c y st adenoma and c y st adenoc arc inoma appear as w ell- def ined int rahepat ic masses c onsist ing of nonenhanc ing c y st ic spac es out lined by higher at t enuat ing w alls or sept a (289,399,552). Mural and sept al nodules or sof t t issue papillary projec t ions, w hen present , usually undergo c ont rast enhanc ement (115). Oc c asionally , c alc if ic at ion may be ident if ied w it hin t he sof t t issue c omponent s of t he t umor (115,399). On bot h T 1- and T 2- w eight ed MR images, t he c y st ic loc ules hav e v ariable signal int ensit y depending on t heir prot ein c ont ent and t he presenc e or absenc e of hemorrhage (F ig. 12- 64)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1873

12 - Liver (82,454,653). On T 1- w eight ed images t hose c ont aining serous f luid are generally hy point ense, t hose c ont aining muc inous f luid isoint ense or hy perint ense, and t hose c ont aining hemorrhagic f luid hy perint ense relat iv e t o liv er (454,501). In hemorrhagic lesions, a f luid- f luid lev el may be present (454). Alt hough sept al nodularit y is suggest iv e of malignanc y (82), biliary c y st adenoma and c y st adenoc arc inoma generally c annot be dist inguished reliably on imaging st udies. Suc h a dist inc t ion is not c linic ally nec essary ,

how ev er, as t he t reat ment f or bot h t umors is surgic al exc ision bec ause of t he presumed malignant pot ent ial of biliary c y st adenoma. Epit helioid hemangioendot helioma is a rare malignant hepat ic neoplasm of v asc ular origin t hat oc c urs in adult s of P.880 all ages, more c ommonly in w omen (310). It is a low t o int ermediat e grade malignanc y w it h 43% of pat ient s surv iv ing great er t han or equal t o 5 y ears af t er diagnosis (485). T he t umor c onsist s of mult iple, most ly peripheral, solid nodules c omposed of my xoid st roma w it h a relat iv ely hy poc ellular c ent er and margins of inc reased c ellularit y (533). At t he periphery of some t umors a narrow c onc ent ric av asc ular zone is produc ed by inv asion of hepat ic sinusoids, v enules, and small port al v ein branc hes (533). As t he nodules inc rease in size t hey c oalesc e t o f orm large c onf luent masses, and w it h ext ensiv e hepat ic inv olv ement , c ompensat ory enlargement of uninv olv ed port ions of t he liv er may oc c ur (224,533,664). Calc if ic at ion is oc c asionally present . Lesions adjac ent t o t he liv er c apsule of t en produc e c apsular ret rac t ion (533,664). T he imaging appearanc e of epit helioid hemangioendot helioma c orresponds c losely t o it s gross morphologic and hist ologic appearanc e. T he lesions are mult iple and predominant ly peripheral w it h t he larger lesions c oalesc ing t o f orm c onf luent masses (F igs. 12- 65 and 12- 66). Capsular ret rac t ion is f requent ly present (see F ig. 12- 65), and c alc if ic at ion is oc c asionally seen. On unenhanc ed CT , t he lesions are hy poat t enuat ing relat iv e t o normal hepat ic parenc hy ma. Af t er IV c ont rast medium administ rat ion, t he t umor enhanc es peripherally (see F igs. 12- 65 and 12- 66). In about half of pat ient s, a more peripheral hy poat t enuat ing rim c orresponding t o t he t hin av asc ular rim seen at pat hologic examinat ion c an be ident if ied (533). T he t umor is hy point ense relat iv e t o hepat ic parenc hy ma on T 1- w eight ed MR images and het erogeneously or homogeneously hy perint ense on T 2- w eight ed images (440,528,533) (see F ig. 12- 66). T he periphery of t he t umor enhanc es af t er IV gadolinium administ rat ion (440,533).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1874

12 - Liver

F igure 12- 65 Epit helioid hemangioendot helioma. Unenhanc ed CT image (A) show s t w o peripheral hy poat t enuat ing liv er masses (M). T he large right lobe mass represent s c oalesc enc e of sev eral smaller lesions t hat w ere present on prior examinat ions. Art erial (B), port al v enous (C ), and equilibrium phase (D) images demonst rat e peripheral enhanc ement w it h gradual c ent ripet al progression. Not e t he c apsular ret rac t ion (ar r ow s) assoc iat ed w it h t he masses and hy pert rophy of t he remaining normal hepat ic parenc hy ma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1875

12 - Liver

F igure 12- 66 Epit helioid hemangioendot helioma. Post c ont rast CT (A) demonst rat es a large peripheral c onf luent mass w it h mild enhanc ement . T he mass is hy point ense on T 1- w eight ed (B) and hy perint ense on T 2- w eight ed (C ) MR images.

P.881 Primary hepat ic angiosarc oma is a rare malignant neoplasm deriv ed f rom endot helial c ells (141). Prognosis is poor w it h most pat ient s surv iv ing less t han 1 y ear af t er diagnosis and 50% t o 60% of pat ient s hav ing met ast at ic disease at present at ion (401,471). Hepat ic angiosarc oma has been assoc iat ed w it h exposure t o t horium dioxide (T horot rast ), v iny l c hloride, and arsenic (471,648), as w ell as w it h sy st emic diseases suc h as hemoc hromat osis and neurof ibromat osis (427,788). T he t umor most c ommonly present s as mult iple small nodules or as a large mass w it h or w it hout sat ellit e nodules (81,401,639). Rarely it may be dif f usely inf ilt rat ing (389,401). Large masses may c ont ain ext ensiv e areas of sinusoidal dilat ion, f requent ly w it h hemorrhage and nec rosis (141,662). Rupt ure of a peripheral nodule or large mass may result in hemoperit oneum (473,880).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1876

12 - Liver

F igure 12- 67 Angiosarc oma. Cont rast - enhanc ed CT image show s a v asc ular right hepat ic lobe mass w it h irregular areas of c ent ral and peripheral enhanc ement . T he high at t enuat ion mat erial (ar r ow heads) adjac ent t o t he lesion represent s perihepat ic blood sec ondary t o c apsular rupt ure.

On unenhanc ed CT , hepat ic angiosarc oma is hy poat t enuat ing exc ept f or areas of f resh hemorrhage, w hic h may be iso- or hy perat t enuat ing. Af t er IV c ont rast administ rat ion, angiosarc oma demonst rat es a v ariable enhanc ement pat t ern, w hic h may inc lude nodular, irregular, or ring- shaped areas of enhanc ement (F ig. 12- 67). Alt hough t he enhanc ement pat t ern of angiosarc oma has been report ed P.882 t o simulat e t hat of hemangioma (321,483,829), st udies perf ormed w it h mult iphase imaging hav e show n t hat t he c ombinat ion of unenhanc ed, art erial, and port al v enous phase images demonst rat es f eat ures of angiosarc oma t hat dist inguish it f rom hemangioma (401,639). Hemangioma t y pic ally show s areas of peripheral nodular enhanc ement w it h at t enuat ion similar t o t hat of t he aort a during all enhanc ement phases and c ent ripet al progession of enhanc ement . T he areas of enhanc ement in angiosarc oma of t en are c ent ral in loc at ion, irregular in shape, and hav e a low er at t enuat ion t han t hat of t he aort a on at least one imaging phase (401,639), alt hough t he enhanc ement progression may be c ent ripet al. T hus on mult iphase helic al CT examinat ions angiosarc oma generally does not f ulf ill t he c rit eria nec essary t o diagnose hemangioma and is more likely t o simulat e hy perv asc ular met ast ases (401). T he MRI appearanc e of angiosarc oma v aries depending on t he size of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1877

12 - Liver lesion. On T 1- w eight ed images small masses may appear hy point ense or hy perint ense relat iv e t o liv er, w hereas large masses of t en c ont ain areas of high signal int ensit y due t o hemorrhage (401). On T 2- w eight ed images t he masses are hy perint ense (321,603). Large masses may show marked het erogeneit y on T 2- w eight ed images w it h f oc al areas of high int ensit y and sept umlike or rounded areas of low int ensit y (401). Dy namic gadoliniumenhanc ed images show het erogeneous enhanc ement on art erial and port al v enous phase images, w it h progressiv e enhanc ement on delay ed imagaes (401,653). Undif f erent iat ed (embry onal) sarc oma of t he liv er is a rare malignant t umor of

mesenc hy mal origin t hat oc c urs primarily in older c hildren and y oung adult s. It is believ ed t o be t he malignant c ount erpart of mesenc hy mal hamart oma of t he liv er (687). Prognosis is poor, w it h a median surv iv al of less t han 1 y ear (687). Grossly , undif f erent iat ed (embry onal) sarc oma is a large, solit ary , globular mass w it h areas of nec rosis, hemorrhage, and c y st ic gelat inous degenerat ion (880). A w ell- def ined f ibrous pseudoc apsule is of t en present (687). Hist ologic ally , it c onsist s of undif f erent iat ed st ellat e and spindle c ell sarc omat ous t issue in a my xoid st roma (880). On CT t he appearanc e is usually t hat of a large, predominant ly c y st - like mass c ont aining sept at ions and peripheral solid c omponent s t hat undergo c ont rast enhanc ement (545,687). Less c ommonly , t he mass is predominant ly solid (687). Radiologic - pat hologic c orrelat ion has demonst rat ed t hat alt hough t he mass usually appears c y st ic on CT images, it of t en is solid or nearly solid at gross pat hology (84). T he c y st - like appearanc e t heref ore may be due t o t he high w at er c ont ent of abundant my xoid st roma w it hin t he lesion (84). A t hin, w ell- def ined rim of sof t t issue, c orresponding t o t he f ibrous pseudoc apsule seen on gross spec imens, c an oc c asionally be ident if ied (687). On T 1- w eight ed MR images, t he c y st ic port ions of t he mass are predominant ly hy point ense w it h oc c asional hy perint ense areas represent ing hemorrhage (491,653,658,894). On T 2w eight ed images, t he mass is predominant ly hy perint ense. T he sept a and f ibrous pseudoc apsule are hy point ense on T 2- w eight ed images but may be hy point ense (491,653) or hy perint ense (658) on T 1- w eight ed images. Af t er Gd- c helat e administ rat ion t he mass show s mild delay ed het erogeneous enhanc ement w it h lac k of enhanc ement of t he c ent ral port ion of t he t umor (658,894).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1878

12 - Liver

F igure 12- 68 Hepat ic non- Hodgkin ly mphoma in t w o pat ient s. Cont rast enhanc ed CT image (A) show s a large c onf luent hy poat t enuat ing mass in t he lef t hepat ic lobe, w it h adjac ent gast rohepat ic ligament ly mphadenopat hy (ar r ow s). Cont rast - enhanc ed CT image (B) show s mult iple relat iv ely homogeneous hy poat t enuat ing hepat ic masses in a pat ient w it h primary nasophary ngeal ly mphoma.

Primary ly mphoma of t he liv er is rare but is inc reasing in inc idenc e as a result of inc reasing numbers of pat ient s w ho are immunoc ompromised sec ondary t o ac quired immunodef ic ienc y sy ndrome (AIDS) (141,594) and organ t ransplant at ion (285,286,366). It is generally of t he non- Hodgkin t y pe and appears at CT as one or more large disc ret e masses (231,594,708) (F ig. 1268). Cont rast enhanc ement P.883 c harac t erist ic s are v ariable (231,708), but t he masses of t en demonst rat e mild homogeneous or slight ly het erogeneous enhanc ement (see F ig. 12- 68). A t hin enhanc ing rim is seen in some pat ient s (677). Rarely , non- Hodgkin ly mphoma inv olv ing t he liv er may produc e ext ensiv e int rahepat ic periport al hy poat t enuat ion (133). On MRI, hepat ic ly mphoma generally appears hy point ense on T 1- w eight ed images but may be hy point ense or hy perint ense on T 2- w eight ed images (372). Enhanc ement af t er Gd- c helat e administ rat ion is v ariable, ranging f rom mild t o int ense (372). Sec ondary inv olv ement of t he liv er by ly mphoma is muc h more c ommon t han t he primary f orm, being report ed at aut opsy in more t han half of pat ient s (692). Sec ondary hepat ic ly mphoma is more c ommonly mult inodular or dif f usely inf ilt rat ing (231,708), but ov erlap bet w een t he appearanc es of primary and sec ondary hepat ic ly mphoma exist s.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1879

12 - Liver T he CT and MRI f eat ures of hepat ic ly mphoma are nonspec if ic and do not allow dif f erent iat ion f rom ot her solit ary or mult ic ent ric hepat ic masses.

Percutaneous Tumor Ablation and Cryosurgery Liv er t umor ablat ion c an be perf ormed w it h a v ariet y of t ec hniques inc luding radiof requenc y (RF ), mic row av e, laser and et hanol ablat ion, c ry ot herapy , and c hemoembolizat ion. CT and/or MRI are t he imaging met hods used most c ommonly t o ev aluat e pat ient s af t er t reat ment t o doc ument adequat e ablat ion or diagnose residual or rec urrent t umor (35,36,125,168,438,745). Af t er RF ablat ion, adequat ely t reat ed lesions are eit her c omplet ely hy poat t enuat ing on CT or c ont ain a v ariable c ent ral area of high at t enuat ion f rom t umor dessic at ion (168,465). F or t reat ed met ast ases, t he v olume of t he low at t enuat ion area should be slight ly larger t han t hat of t he original t umor, w it h an addit ional c irc umf erent ial margin of 5 t o 10 mm t o inc lude areas of mic rosc opic inv asion int o t he adjac ent liv er parenc hy ma (125,465). F or t reat ed HCCs, t he low at t enuat ion v olume usually is equiv alent t o t hat of t he original t umor bec ause t hermal nec rosis out side t he t umor margins is impeded by t he poor c onduc t iv it y of t he surrounding c irrhot ic liv er (439). On c ont rast enhanc ed CT t he ablat ed area does not enhanc e (F ig. 12- 69), but a t hin enhanc ing rim relat ed t o hy peremia and inf lammat ory c hange may be seen w it hin t he f irst sev eral mont hs af t er t reat ment (168,240,439). T he rim enhanc es predominant ly during t he art erial phase, may be irregular in shape and t hic kness, but should c omplet ely surround t he ablat ed area (439,465). A peripheral w edge- shaped area of enhanc ement adjac ent t o t he RF - t reat ed area is somet imes seen on art erial phase images and likely represent s art erioport al shunt ing c aused by needle punc t ure or t hermal damage (168,439). Residual or rec urrent t umor appears as disc ret e nodular enhanc ement or irregular t hic kening at t he ablat ion margin (168,439,465). Residual or rec urrent hepat oc ellular c arc inoma demonst rat es art erial phase enhanc ement , w hereas hy pov asc ular met ast ases demonst rat e port al v enous or delay ed phase (5 t o 10 minut es af t er c ont rast medium administ rat ion) enhanc ement (97,168,439). On f ollow - up MRI examinat ions, adequat ely t reat ed lesions hav e v ariable signal int ensit y on T 1- w eight ed images (F ig. 12- 70) and are hy point ense on T 2w eight ed images (168,745). A hy perint ense rim may be seen surrounding t he lesion, likely due t o edema (465), and oc c asionally marked hy perint ensit y on T 2- w eight ed images is due t o hemorrhage or liquef ac t iv e nec rosis (168,745).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1880

12 - Liver Residual or rec urrent t umor appears as one or more hy perint ense f oc i on T 2w eight ed images, w it h peripheral nodular or irregular enhanc ement on c ont rast - enhanc ed images (168,465). When ev aluat ing f ollow - up CT or MRI examinat ions, it is import ant t o look c aref ully f or new hepat ic lesions and ext rahepat ic t umors, as t hey oc c ur w it h great er f requenc y t han loc al rec urrenc es (125). Wit hin t he f irst 2 w eeks af t er c ry osurgery , c ont rast - enhanc ed CT demonst rat es w ell- def ined w edge- shaped, round, or t eardrop- shaped, hy poat t enuat ing lesions t hat ext end t o t he liv er c apsule (412,524). Nearly all lesions c ont ain areas of hemorrhage, and approximat ely one t hird c ont ain gas bubbles, w hic h usually disappear af t er sev eral w eeks. Approximat ely one half demonst rat e peripheral enhanc ement (412). Most suc c essf ully t reat ed lesions dec rease in size and may be assoc iat ed w it h f oc al hepat ic at rophy (524). Small lesions may disappear c omplet ely , but large lesions of t en persist as hy poat t enuat ing f oc i. Hepat ic subc apsular hemorrhage and perihepat ic f luid c ollec t ions are c ommon assoc iat ed f indings w it hin t he f irst 2 w eeks af t er t reat ment (412). If t he early c ry olesion is not larger t han and c omplet ely inc lusiv e of t he original t umor, t umor ablat ion has been inc omplet e (524). T umor rec urrenc e should be suspec t ed if a lesion persist s or show s inc reasing at t enuat ion or

size (524). Complic at ions af t er c ry osurgery may be dif f ic ult t o det ec t w it h CT bec ause t he normal post c ry ot herapy appearanc e is similar t o t hat seen in pat ient s w it h hepat ic absc ess or inf arc t ion (412). An inc rease in t he number or size of gas bubbles in t he c ry olesion suggest s dev elopment of an absc ess (524). Biliary duc t al dilat ion af t er c ry ot herapy may be due t o obst ruc t ion by t umor but c an be due t o f reezing injury , w hic h somet imes result s in biliary st enosis (524). At MRI af t er c ry ot herapy , an adequat ely f rozen area has low signal int ensit y on T 1- w eight ed images, high signal int ensit y on T 2- w eight ed images, and show s no enhanc ement af t er gadolinium administ rat ion (64). Ot her f indings at MRI c orrespond t o t hose seen at CT . Perc ut aneous et hanol ablat ion, using ult rasound or CT guidanc e, is an ac c ept ed met hod f or t reat ing hepat oc ellular c arc inoma and some hepat ic met ast ases (469,470,730). T he unenhanc ed CT appearanc e of a suc c essf ully t reat ed t umor immediat ely af t er t herapy is t hat of a markedly hy poat t enuat ing, nec rot ic area inv olv ing t he ent ire v olume of t he preexist ing

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1881

12 - Liver t umor (344). F indings predic t iv e of inadequat e t reat ment inc lude lac k of signif ic ant hy poat t enuat ion, P.884 an area of nec rosis t hat does not ext end t o t he t umor margin, and persist ent peripheral nodularit y surrounding t he sit e of nec rosis (344). At MRI perf ormed at least 1 mont h af t er t reat ment , adequat ely t reat ed lesions usually appear

hy perint ense on T 1- w eight ed images, hy point ense on T 2- w eight ed images, and demonst rat e no enhanc ement on T 1- w eight ed images af t er gadolinium- c helat e administ rat ion (36,742,743). Inadequat ely t reat ed t umors usually show areas of hy perint ensit y on T 2- w eight ed images and areas of c ont rast enhanc ement on T 1- w eight ed post gadolinium images (36,743,744). How ev er, in a small perc ent age of c ases, a f alse–posit iv e f inding of peripheral gadolinium enhanc ement may be due t o a rim of v asc ular f ibrous t issue surrounding t he nec rot ic nodule (744), and an area of T 2 hy perint ensit y may be due t o hemorrhagic inf arc t ion, liquef ac t iv e nec rosis, or c hronic inf lammat ory t issue (36,744). Alt hough t he MRI appearanc e of hepat ic lesions t reat ed w it h perc ut aneous et hanol ablat ion w as f ound in one st udy t o be an unreliable indic at or of residual t umor (566), it has been f ound by ot her inv est igat ors t o be an ac c urat e means of f ollow ing pat ient s t reat ed w it h t his t ec hnique (36,566,742,743).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1882

12 - Liver

F igure 12- 69 Hepat ic met ast ases t reat ed w it h radiof requenc y ablat ion. Prec ont rast (A), art erial phase (B), and port al v enous phase (C ) c ont rast enhanc ed images show t hree peripheral hy poat t enuat ing areas t hat demonst rat e no c ont rast enhanc ement .

T ransc at het er art erial c hemoembolizat ion is used most of t en t o t reat hepat oc ellular c arc inoma pat ient s w ho hav e large or mult iple lesions (458). Complet e t umor nec rosis of large lesions is ac hiev ed in a minorit y of pat ient s, and residual t umor is usually ident if ied at f ollow - up CT (F ig. 12- 71) or MRI (F ig. 12- 72) (118,612). Chemoembolizat ion proc edures are usually perf ormed w it h iodized oil. Areas w it hin t he t umor t hat ret ain iodized oil af t er approximat ely 4 w eeks are c onsidered t o be nec rot ic (118,797). T he ac c umulat ion pat t ern of iodized oil w it hin t he t umor c orrelat es roughly w it h out c ome. Homogeneous iodized oil ac c umulat ion w it hin t he t umor and inc omplet e ac c umulat ion w it h a part ial def ec t are assoc iat ed w it h disease- f ree rat es 1 y ear af t er t reat ment of 81% and 48%, respec t iv ely (458). Worse response rat es are seen w it h f aint ac c umulat ion and no ac c umulat ion of iodized oil w it hin t he t umor. A limit at ion of CT in assessing pat ient s af t er c hemoembolizat ion is t hat t he high densit y of t he iodized oil w it hin t he t umor

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1883

12 - Liver and t he art if ac t s c aused by it make assessment of residual t umor enhanc ement dif f ic ult (see F ig. 12- 71) (355). MR imaging does not hav e t his limit at ion, as iodized oil does not modif y t he signal int ensit y of eit her t umor nodules t hat ac c umulat e it or P.885 P.886 non- neoplast ic hepat ic parenc hy ma in w hic h it is deposit ed (154,903).

F igure 12- 70 Hepat oc ellular c arc inoma t reat ed w it h radiof requenc y ablat ion. Unenhanc ed T 1- w eight ed image (A) show s t w o peripheral hy perint ense lesions. Gadolinium- enhanc ed image (B) show s t hat t he lesions are hy point ense relat iv e t o enhanc ed liv er parenc hy ma but hav e int ernal signal. Subt rac t ion image (C ) demonst rat es no enhanc ement w it hin t he lesions, indic at ing adequat e t reat ment .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1884

12 - Liver

F igure 12- 71 Hepat oc ellular c arc inoma t reat ed w it h c hemoembolizat ion. Pret reat ment c ont rast - enhanc ed CT image (A) show s a hy perat t enuat ing subc apsular mass dist ort ing t he liv er margin. Lat e hepat ic art erial phase image (B) af t er t ransc at het er art erial c hemoembolizat ion demonst at es c omplet e replac ement of t he mass w it h v ery high at t enuat ion iodized oil. No enhanc ement is demonst rat ed at t he periphery of t he mass, but t he densit y of t he iodized oil limit s ev aluat ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1885

12 - Liver F igure 12- 72 Hepat oc ellular c arc inoma t reat ed w it h c hemoembolizat ion. Pret reat ment art erial phase gadolinium- enhanc ed T 1- w eight ed MR image (A) show s t w o hy perint ense masses in segment VII of t he liv er. Art erial (B) and port al v enous phase (C ) images af t er c hemoembolizat ion show part ial enhanc ement of bot h lesions, indic at ing inc omplet e t reat ment .

CT and MRI are also usef ul f or demonst rat ing c omplic at ions af t er t umor ablat ion (125,674,843). T he most c ommon c omplic at ions inc lude pneumot horax, pleural ef f usion, hepat ic absc ess, int rahepat ic or perit oneal hemorrhage, and bile duc t injuries result ing in st ric t ure, f ist ula, or int rahepat ic biloma (125,674,843). Less c ommonly , segment al hepat ic inf arc t ion may oc c ur (750,843).

ABSCESSES Pyogenic Abscesses Hepat ic absc esses c an result f rom inf ec t ion by f iv e dif f erent rout es: (a) biliary , due t o asc ending c holangit is; (b) port al v enous, due t o bac t eremia f rom int raabdominal sepsis; (c ) art erial, due t o sept ic emia; (d) loc al ext ension, due t o suppurat ion inv olv ing neighboring t issues; and (e) t raumat ic , due t o blunt or penet rat ing injuries (496,685). Pat ient s usually are sy mpt omat ic , present ing c ommonly w it h f ev er, malaise, and abdominal disc omf ort . Prior t o t he av ailabilit y of c ross- sec t ional imaging t ec hniques, t he mort alit y rat e f rom hepat ic absc esses w as approximat ely 50% (425,644). During t he past 30 y ears, t he morbidit y and mort alit y relat ed t o hepat ic absc esses has dec reased c onsiderably , ow ing t o improv ed met hods of diagnosis and t reat ment (644). T he c harac t erist ic CT appearanc e of hepat ic absc ess is t hat of a round or irregularly shaped hy poat t enuat ing mass w it h a peripheral c apsule t hat undergoes c ont rast enhanc ement (see F ig. 12- 73). Of t en a narrow t ransit ion zone of slight ly dec reased at t enuat ion v alue is present bet w een t he low at t enuat ing c ent ral port ion of t he mass and t he higher at t enuat ing rim (806). In some c ases, dy namic c ont rast - enhanc ed imaging demonst rat es a doublet arget appearanc e, c onsist ing P.887 of a hy podense c ent ral area surrounded by a hy perdense ring, w hic h is in t urn surrounded by a hy podense zone t hought t o c orrespond t o loc alized edema

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1886

12 - Liver (F ig. 12- 73) (496). Hepat ic absc esses may be uniloc ular or mult iloc ular (F igs. 12- 74 and 12- 75). When mult iple absc esses are present , t hey somet imes

appear as a f oc al c lust er of lesions (“ c lust er sign” ), w hic h is suggest iv e of t heir py ogenic nat ure (339). T he CT appearanc e of hepat ic absc ess, alt hough c harac t erist ic , is nonspec if ic and c an be simulat ed by c y st ic or nec rot ic met ast ases (see F ig. 12- 60). Cent ral gas, appearing eit her as mult iple bubbles (F ig. 12- 76) or a gas–f luid lev el, is highly suggest iv e of absc ess but is present in only a small minorit y of c ases.

F igure 12- 73 Py ogenic absc ess. Cont rast - enhanc ed CT image show s a round low at t enuat ion mass w it h an enhanc ing rim, surrounded by a c ollar of edemat ous hy poat t enuat ing hepat ic parenc hy ma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1887

12 - Liver

F igure 12- 74 Py ogenic absc ess. Cont rast - enhanc ed CT image show s a large mult iloc ulat ed c y st ic hepat ic mass w it h mult iple small peripheral lobulat ions and a t hin enhanc ing w all.

F igure 12- 75 Py ogenic absc ess. Cont rast - enhanc ed CT image show s a large het erogeneous peripheral hepat ic mass c onsist ing of numerous c onf luent small hepat ic absc esses.

At MRI, hepat ic absc esses appear as solit ary or mult iple w ell- def ined round, ov al, or lobulat ed masses t hat are hy point ense relat iv e t o liv er parenc hy ma on

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1888

12 - Liver T 1- w eight ed images and markedly hy perint ense on T 2- w eight ed images (29,525). Approximat ely one t hird of lesions are P.888 surrounded by a loc al area of slight ly inc reased signal int ensit y on T 2w eight ed images, represent ing perilesional edema (F ig. 12- 77) (29,525). Most lesions demonst rat e rim enhanc ement af t er IV gadolinium- c helat e administ rat ion (see F igs. 12- 77; 12- 78 and 12- 79) (525,713,858). A small perc ent age of absc esses c ont ain int ernal sept at ions, w hic h also enhanc e on post c ont rast images (see F ig. 12- 78) (29). Oc c asionally , a f luid- f luid lev el or dependent lay ering of prot einac eous debris may be ident if ied (29).

F igure 12- 76 Gas- c ont aining py ogenic absc ess. A round hy poat t enuat ing mass near t he dome of t he liv er c ont ains mult iple f oc i of gas.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1889

12 - Liver

F igure 12- 77 Py ogenic absc ess. Unenhanc ed T 2- w eight ed MR image (A) show s a small hy perint ense hepat ic mass. T he mass is surrounded by a loc al area of slight ly inc reased signal int ensit y due t o perilesional edema. Art erial phase gadolinium- enhanc ed T 1- w eight ed image (B) show s t hat t he mass is c y st ic w it h an enhanc ing w all. T he w all is bordered by a part ial hy point ense rim (ar r ow s) due t o edema and an irregular area of hy perint ensit y (ar r ow heads) relat ed t o hy peremia. Port al v enous phase image bet t er demonst rat es t he enhanc ing w all and t he lobulat ed c ont our of t he absc ess.

T he v ast majorit y of py ogenic hepat ic absc esses are suc c essf ully t reat ed w it h a c ombinat ion of ant ibiot ic s and perc ut aneous drainage (644,667). Ev en mult iloc ulat ed absc esses c an be suc c essf ully drained by a single perc ut aneous c at het er bec ause t he sept a of t en are inc omplet e (48). Absc esses w it h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1890

12 - Liver int rahepat ic biliary c ommunic at ion are also amenable t o perc ut aneous t reat ment but may require a longer durat ion of drainage (161).

Nonpyogenic Abscesses Amebic Abscess Amebiasis is c aused by t he parasit e Ent am oeba hist oly t ic a, w hic h is endemic in t ropic al and subt ropic al c limat es and is also present in t he sout hw est ern Unit ed St at es. Hepat ic P.889 absc ess is t he most c ommon ext raint est inal c omplic at ion of amebiasis, oc c urring in 3% t o 9% of c ases (827). Pat ient s usually present w it h right upper- quadrant pain. T he CT appearanc e of amebic absc ess is nonspec if ic . It usually appears as a solit ary , uniloc ular round or ov al hy poat t enuat ing (10 t o 20 HU) mass w it h an enhanc ing w all (665) (F ig. 12- 80). T he margin of t he absc ess may be smoot h or nodular, and an inc omplet e hy poat t enuat ing rim of edema is somet imes present (665). Approximat ely t hree quart ers of hepat ic amebic absc esses oc c ur in t he right lobe, a phenomenon t hat may be explained by pref erent ial right - sided st reaming v ia t he port al v ein of seeded blood f rom t he superior mesent eric v ein, w hic h drains t he right c olon (643). Ext rahepat ic abnormalit ies are c ommon and inc lude pleural ef f usion, perihepat ic f luid c ollec t ion, gast ric or c olonic inv olv ement , and ret roperit oneal ext ension (665).

F igure 12- 78 Py ogenic absc esses in a pat ient w it h rec urrent py ogenic c holangiohepat it is. Gadolinium- enhanc ed T 1- w eight ed MR image show s t w o

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1891

12 - Liver mult iloc ulat ed hepat ic absc esses (ar r ow s) w it h enhanc ing w alls and mult iple int ernal enhanc ing sept at ions. T he dilat ed bile duc t s in t he lef t hepat ic lobe w ere c aused by obst ruc t ing int rahepat ic biliary st ones.

F igure 12- 79 Py ogenic absc esses in a pat ient w it h disseminat ed st rept oc oc c al inf ec t ion. Gadolinium- enhanc ed T 1- w eight ed MR image show s mult iple small hy point ense rim- enhanc ing lesions t hroughout t he lef t hepat ic lobe, w hic h is dif f usely dec reased in signal int ensit y due t o edema.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1892

12 - Liver

F igure 12- 80 Amebic absc ess. A large uniloc ular mass w it h an enhanc ing w all demonst rat es a t hin peripheral hy poat t enuat ing rim of surrounding edema (ar r ow heads).

As w it h CT , t he MRI appearanc e of amebic liv er absc ess is nonspec if ic . Lesions are hy point ense relat iv e t o hepat ic parenc hy ma on T 1- w eight ed images, het erogeneously hy perint ense on T 2- w eight ed images (183,668), and hav e a t hic k enhanc ing w all (30). One t o t hree zones of v ary ing signal int ensit y are of t en present peripherally on bot h T 1- and T 2- w eight ed images (183,668). Edema of t he surrounding hepat ic parenc hy ma may be seen as a region of hy perint ensit y on T 2- w eight ed images ext ending f rom t he absc ess t o t he liv er surf ac e (183). Ult rasound, CT , and MRI are c omparable in t he det ec t ion of amebic liv er absc ess (668). Medic al t herapy is generally ef f ec t iv e, but perc ut aneous c at het er drainage may be indic at ed in selec t ed c ases (827).

Fungal Microabscesses F ungal mic roabsc esses of t he liv er oc c ur in immunoc ompromised pat ient s, most c ommonly t hose w it h hemat ologic malignanc ies (213,628,733). Clinic al diagnosis is dif f ic ult bec ause blood c ult ures may be negat iv e and sy mpt oms are of t en nonspec if ic (213). T he c ausat iv e organism is most c ommonly Candida albic ans, but Asper gillus, Cr y pt oc oc c us, and ot her organisms also may be f ound. T he t y pic al CT appearanc e is t hat of mult iple small hy poat t enuat ing masses dist ribut ed dif f usely t hroughout t he liv er (213,628,733) (F ig. 12- 81). Some lesions demonst rat e rim enhanc ement (381,449). Rarely , a c ent ral area of densit y , t hought t o represent hy phae, c an be ident if ied (628). T he spleen and kidney s are also f requent ly inv olv ed (733). T he CT appearanc e P.890 of f ungal mic roabsc esses is nonspec if ic . Met ast ases, ly mphoma, mult if oc al st eat osis, sarc oidosis, bac t erial absc esses, and my c obac t erial inf ec t ion may hav e a similar appearanc e.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1893

12 - Liver

F igure 12- 81 F ungal mic roabsc esses. Cont rast - enhanc ed CT image show s numerous subc ent imet er low at t enuat ion lesions t hroughout t he liv er and spleen t hat w ere due t o disseminat ed Candida albic ans inf ec t ion.

T he MRI appearanc e depends on t he st age of disease. Ac ut e f ungal mic roabsc esses are minimally hy point ense on T 1- w eight ed images and markedly hy perint ense on T 2- w eight ed images (721). Most lesions are mildly hy point ense on gadolinium- enhanc ed images w it hout perilesional enhanc ement , but a minorit y of lesions show rim enhanc ement (721). Subac ut e lesions appear mildly t o moderat ely hy perint ense on bot h T 1- w eight ed and T 2w eight ed images, demonst rat e enhanc ement af t er gadolinium administ rat ion, and are surrounded by a dark ring on all sequenc es (721). T his appearanc e ref lec t s t heir t ransf ormat ion t o nec rot izing granulomas w it h a c ent ral absc ess and peripheral f ibrosis surrounded by a zone of ly mphoc y t es and mac rophages. In t he presenc e of t ransf usional hemosiderosis, t he mac rophages at t he periphery of t he granulomas c ont ain abundant iron, w hic h produc es t he peripheral dark rim (721). Chronic lesions t hat hav e been t reat ed hav e an irregular or poly gonal shape and may be larger t han unt reat ed lesions. T hey appear minimally hy point ense on T 1- w eight ed images and isoint ense or mildly hy perint ense on T 2- w eight ed images (721). In t he absenc e of posit iv e blood c ult ures, a biopsy is required f or c onf irmat ion of t he diagnosis. In addit ion, a normal- appearing liv er on a CT examinat ion of a pat ient w it h suspec t ed f ungal mic roabsc esses does not exc lude t he diagnosis; biopsy is indic at ed in suc h c ases also. Wit h suc c essf ul ant if ungal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1894

12 - Liver

t reat ment , t he hepat ic lesions usually resolv e (46,732); how ev er, suc c essf ully st erilized lesions may persist and undergo c alc if ic at ion (46,732,733).

F igure 12- 82 Hy dat id c y st . Cont rast - enhanc ed CT image show s a large mult iloc ular mass w it h a t hic k w all. Mult iple daught er c y st s line t he periphery of t he mass. Court esy of Jon Carmain, MD.

Echinococcal Disease Hy dat id disease is c aused by t he parasit e Ec hinoc oc c us gr anulosus and, less f requent ly , by E. alv eolar is (m ult iloc ular is). Inf ec t ion by E. gr anulosus is c ommon in sheep- and c at t le- rearing c ount ries inc luding Aust ralia, New Zealand, c ert ain part s of Sout h Americ a, and c ount ries around t he Medit erranean Sea (420). E. alv eolar is is f ound most f requent ly in Europe, Russia, and Siberia, w it h c ases also report ed in Canada, Ic eland, and Alaska (615). T he liv er is t he most c ommon sit e of inv olv ement (39). Hepat ic inv olv ement by E. gr anulosus appears at CT as w ell- def ined, uni- or mult iloc ular c y st s w it h t hin or t hic k w alls (39,141,351) (F ig. 12- 82). Daught er c y st s are usually seen as smaller c y st s w it h sept at ions at t he periphery of t he mot her c y st . T y pic ally , t he f luid in t he daught er c y st s has a low er at t enuat ion v alue t han t hat w it hin t he mot her c y st (see F ig. 12- 82) (39,127,351,623,634,801). Calc if ic at ion in t he w all or sept at ions is c ommon (39,127,351,623), but t he w all may appear high in at t enuat ion on unenhanc ed images ev en in t he absenc e of c alc if ic at ion (634). T he MRI appearanc e of hy dat id c y st is nonspec if ic and ov erlaps w it h t hat of ot her hepat ic c y st s. How ev er, t he presenc e of a hy point ense rim on T 1- and T 2- w eight ed images and a mult iloc ulat ed appearanc e are c onsidered t o be dist inc t iv e f eat ures of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1895

12 - Liver t his lesion (147,281,352). T he daught er c y st s generally are hy point ense relat iv e t o t he int rac y st ic f luid on T 1- w eight ed images and hy perint ense on T 2- w eight ed images. During healing, dense c alc if ic at ion of all c omponent s of t he c y st may oc c ur (39) (F ig. 12- 83). Int rahepat ic c omplic at ions of hy dat id c y st s inc lude c y st rupt ure and inf ec t ion (634). T he st andard t reat ment of hepat ic hy dat id c y st is surgic al remov al bec ause medic al t herapy is usually inef f ec t iv e (615). Suc c essf ul long- t erm result s of perc ut aneous drainage of hy dat id c y st s c ombined w it h albendazole P.891 t herapy hav e been report ed and prov ide an alt ernat iv e t o surgic al t reat ment in some c ases (8,78,379,380).

F igure 12- 83 Hy dat id c y st . Cont rast - enhanc ed CT image show s a w elldef ined mass w it h ext ensiv e int ernal c alc if ic at ion assoc iat ed w it h t he healing proc ess.

Hepat ic inv olv ement by E. alv eolar is produc es an appearanc e v ery dif f erent f rom t hat produc ed by E. gr anulosus, c onsist ing of inf ilt rat ing solid masses w it h indist inc t margins (99) or mult iple irregular lesions sc at t ered t hroughout t he inv olv ed liv er (142). T he masses are hy poat t enuat ing and do not undergo c ont rast enhanc ement . Clust ers of mic roc alc if ic at ion are present in 90% of pat ient s (130). T he CT appearanc e is nonspec if ic and may be similar t o t hat of hepat ic met ast ases. Large areas of c ent ral nec rosis are dif f ic ult t o dif f erent iat e f rom absc esses (142). At MRI, f ibrous and parasit ic t issue is usually hy point ense on T 1- w eight ed and T 2- w eight ed images but may be

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1896

12 - Liver

hperint ense on T 2- w eight ed images (130). Areas of nec rosis demonst rat e v ery high signal on T 2- w eight ed images. A disadv ant age of MRI is it s poor demonst rat ion of c alc if ic at ions, w hic h are present in most pat ient s (130). Surgic al resec t ion c ombined w it h ant iparasit ic pharmac ologic t herapy is t he t reat ment of c hoic e (657).

Schistosomiasis Sc hist osom iasis japonic a is c ommon in China, T aiw an, and t he sout hern Philippines (13). Imaging has not play ed an import ant role in t he diagnosis of ac ut e sc hist osomiasis c aused by t his organism (555). In a single report ed c ase, CT demonst rat ed innumerable hy poat t enuat ing lesions t hroughout t he liv er (100). T he c hronic hepat ic manif est at ions of t he disease c onsist of a c harac t erist ic pat t ern of c apsular and band- like parenc hy mal c alc if ic at ion orient ed perpendic ular t o t he liv er c apsule (13,542). Linear parenc hy mal and c apsular enhanc ement are also c harac t erist ic (542). Not c hing of t he liv er surf ac e somet imes giv es t he liv er an irregular c ont our, and hepat ic f ibrosis may c ause prominenc e of t he periport al f at (13). MRI does not ac c urat ely depic t t he c harac t erist ic sept al c alc if ic at ions, w hic h may appear as linear areas of signal v oid, but it does demonst rat e t he f ibrous sept a, w hic h appear hy point ense on T 1- w eight ed images and hy perint ense on T 2- w eight ed images (629). Pat ient s w it h hepat ic sc hist osomiasis japonic a are at inc reased risk of dev eloping hepat oc ellular c arc inoma (13,542). Sc hist osom iasis m ansoni is c ommon in east ern, c ent ral, and w est ern Af ric a and part s of t he Middle East , part ic ularly Egy pt and t he Sudan (615). Hepat ic manif est at ions inc lude f ibrosis, w hic h appears at CT as hy poat t enuat ing rounded areas in t he periport al region w it h linear, branc hing bands t hat enhanc e on post c ont rast images (192). At MRI, t he peiport al bands are hy point ense relat iv e t o liv er on T 1- w eight ed images and hy perint ense on T 2w eight ed images, w it h marked enhanc ement af t er gadolinium administ rat ion (629).

Uncommon Hepatic Infections T uberc ulous inv olv ement of t he liv er may appear at CT as mult iple hy poat t enuat ing nodular lesions, but hepat omegaly may be t he only manif est at ion (555). In t he healing st age, CT may demonst rat e dif f use c alc if ic at ions. At MRI, t he lesions are hy point ense on T 1- w eight ed images and hy point ense or isoint ense on T 2- w eight ed images (555).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1897

12 - Liver

Bac illary angiomat osis is an inf ec t ion oc c urring in immunoc ompromised pat ient s c aused by Bar t onella henselae, t he organism t hat c auses c at sc rat c h f ev er in nonimmunoc ompromised pat ient s (555). It is an unusual hemangioprolif erat iv e lesion t hat primarily af f ec t s t he skin but c an disseminat e t o inv olv e ot her organs, inc luding t he liv er (881). When it inv olv es t he liv er, bac illary angiomat osis may result in peliosis hepat is, a rare c ondit ion c harac t erized by c y st ic , blood- f illed spac es in t he hepat ic parenc hy ma (881). T he CT appearanc e of hepat ic inv olv ement by bac illary angiomat osis c onsist s of mult iple hy poat t enuat ing or hy perat t enuat ing lesions less t han 1 c m in diamet er sc at t ered t hroughout t he liv er (555,881). It may be dif f ic ult t o dist inguish t his inf ec t ion f rom ot her disseminat ed diseases oc c urring in immunoc ompromised pat ient s inc luding bac t erial, v iral, or f ungal mic roabsc esses, t uberc ulosis, AIDS- relat ed ly mphoma, and Kaposi sarc oma (881).

DIFFUSE DISEASES Steatosis Hepat ic st eat osis (f at t y met amorphosis) is t he result of exc essiv e ac c umulat ion of t rigly c erides w it hin hepat oc y t es (10). It is seen in assoc iat ion w it h a v ariet y of c linic al disorders, inc luding alc oholic liv er disease, diabet es mellit us, obesit y , malnut rit ion, c hronic illness, parent eral nut rit ion, sev ere hepat it is, hepat ot oxin exposure, c ort ic ost eroid use, and endogenous c ort ic ost eroid exc ess. Unc ommon c auses inc lude c y st ic f ibrosis, t rauma, Rey e sy ndrome, ac ut e f at t y liv er of pregnanc y , gly c ogen st orage disease, massiv e t et rac y c line P.892 t herapy , and gly c ogen sy nt het ase def ic ienc y (220). T he c linic al present at ion and imaging manif est at ions of hepat ic st eat osis are v aried. F at t y liv er usually is c linic ally “ silent ” but may be assoc iat ed w it h hepat omegaly , right upper- quadrant abdominal pain, or elev at ed serum liv er f unc t ion t est s. Rarely , it may present as ac ut e hepat ic f ailure if it is sec ondary t o hepat ot oxin exposure or t o f at t y liv er of pregnanc y . F at deposit ion in t he liv er c an oc c ur rapidly and also is rapidly rev ersible (37,694,860). Alt hough it is most c ommonly a dif f use proc ess, f at t y met amorphosis f requent ly is nonunif orm or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1898

12 - Liver f oc al. T he mec hanism of f oc al st eat osis is poorly underst ood but may be relat ed t o loc al dif f erenc es in hepat ic v asc ularizat ion (76,487). CT is a sensit iv e, noninv asiv e t ec hnique f or det ec t ing f at t y met amorphosis and f ollow ing it s subsequent progression or regression. An exc ellent c orrelat ion has been demonst rat ed bet w een hepat ic parenc hy mal CT at t enuat ion v alues and t he amount of hepat ic t rigly c erides ident if ied on liv er biopsy (91,170,370). Inc reased hepat ic f at c ont ent produc es a dec rease in mean hepat ic CT at t enuat ion v alue. Marked dif f use st eat osis result s in a c harac t erist ic CT appearanc e in w hic h t he liv er parenc hy ma is low er in at t enuat ion t han t he hepat ic blood v essels on images obt ained w it hout int rav enous c ont rast mat erial (778) (F ig. 12- 84). Milder degrees of dif f use

f at t y c hange c an be diagnosed w hen t he at t enuat ion v alue of t he liv er is less t han t hat of t he spleen on nonc ont rast images. In normal adult s, t he prec ont rast at t enuat ion v alue of t he liv er is c onsist ent ly higher t han t hat of t he spleen w it h a mean dif f erenc e of 8 HU (641). It is more dif f ic ult t o diagnose hepat ic st eat osis on images obt ained af t er administ rat ion of int rav enous c ont rast mat erial bec ause t he spleen of t en bec omes higher in at t enuat ion t han t he liv er af t er a rapid injec t ion of int rav enous c ont rast mat erial. Alt hough one st udy suggest s t hat a dif f erenc e of at least 25 HU bet w een spleen and liv er be used t o diagnose f at t y liv er on post c ont rast images (9), suc h c ont rast enhanc ement dif f erenc es are highly dependent on t he t iming of image ac quisit ion and t he met hod of c ont rast medium administ rat ion (342). T hus t he use of arbit rary at t enuat ion v alue dif f erenc es bet w een spleen and liv er on post c ont rast images may be misleading, espec ially w it h t he rapid image ac quisit ion t imes of mult idet ec t or- row CT . Visual (qualit at iv e) assessment of liv er- spleen at t enuat ion dif f erenc es t o diagnose hepat ic st eat osis result s in a high spec if ic it y but a poor sensit iv it y (334).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1899

12 - Liver

F igure 12- 84 Dif f use hepat ic st eat osis. T he at t enuat ion v alue of t he liv er parenc hy ma is markedly low er t han t hat of t he spleen on t his unenhanc ed CT image. T he int rahepat ic v essels st and out as hy perat t enuat ing st ruc t ures.

T he CT appearanc e of f oc al st eat osis may be dif f ic ult t o dist inguish f rom t hat of primary or sec ondary hepat ic neoplasm or absc ess. How ev er, sev eral c harac t erist ic f eat ures of f oc al st eat osis are of t en helpf ul in dif f erent iat ing it f rom spac e- oc c upy ing hepat ic masses (10,23,139,172,548). F oc al f at t y met amorphosis f requent ly has a segment al or w edge- shaped c onf igurat ion and c harac t erist ic ally produc es no mass ef f ec t or bulging of t he hepat ic c ont our. How ev er, hepat ic inf arc t ion c an hav e a similar appearanc e (7). In addit ion, f oc al f at t y met amorphosis is of t en easy t o c harac t erize w hen it oc c urs in a t y pic al loc at ion suc h as adjac ent t o t he f issure f or t he ligament um t eres (896). Port al and hepat ic v eins of t en c an be seen c oursing in a normal pat t ern t hrough t he af f ec t ed area. How ev er, t his f inding does not exc lude t he presenc e of neoplasm, as hepat ic v essels c an oc c asionally t rav erse met ast at ic lesions (11,436). Rarely , hepat ic st eat osis present s as mult iple small, w ell- def ined nodules t hat c an mimic met ast at ic disease (28,209,408,890) (F ig. 12- 85). T he nodules may hav e a periv asc ular dist ribut ion (see F ig. 12- 85), and some of t he nodules may hav e c ent ral c ores of inc reased densit y mimic king f ungal absc esses (890). Alt hough f oc al f at t y met amorphosis f requent ly present s a dif f ic ult diagnost ic problem at CT , suc h lesions c an c hange dramat ic ally w it h t ime, and repeat CT examinat ion af t er a f ew day s of improv ed nut rit ion may demonst rat e marked

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1900

12 - Liver

improv ement or resolut ion (37). MRI, how ev er, c an readily dist inguish bet w een f oc al st eat osis and spac e oc c upy ing hepat ic lesions (see below ). Dif f use f at t y met amorphosis, alt hough relat iv ely easy t o diagnose, c an c ause hepat ic imaging dif f ic ult ies bec ause it c an obsc ure met ast ases or dilat ed bile duc t s (258,455,660). Conv ersely , f oc al areas of higher at t enuat ion w it hin a region of f at t y c hange may represent neoplast ic masses or f oc i of uninv olv ed (spared) normal liv er (258,418). T he diagnosis of f oc al hepat ic sparing is suggest ed w hen a geographic area of relat iv ely higher at t enuat ion is ident if ied in one or more of t he t y pic al loc at ions f or suc h “ skip” areas suc h as along t he gallbladder f ossa adjac ent t o t he int erlobar f issure, in t he medial segment of t he lef t lobe adjac ent t o t he port a hepat is, or in a subc apsular loc at ion (3,12,455,863). T he c ause of f oc al sparing is loc ally dec reased port al v enous blood f low , w hic h in some c ases is due t o dilut ion of port al blood by aberrant gast ric v eins or ac c essory c y st ic v eins t hat c ommunic at e direc t ly w it h t he port al sy st em (324,369,487,511). P.893 P.894 In some c ases, how ev er, f oc al sparing c an be a sign of an adjac ent hepat ic mass, w hic h has c aused a loc al reduc t ion in port al v enous blood f low (12,228,255). When CT is unable t o prov ide a def init iv e diagnosis, MRI is ext remely usef ul in c harac t erizing t he hepat ic abnormalit y .

F igure 12- 85 Mult if oc al hepat ic st eat osis. Cont rast - enhanc ed CT images (A, B) demonst rat e mult iple round and irregular hy poat t enuat ing areas t hroughout t he liv er. Not e t hat many of t he lesions, part ic ularly t hose near t he dome, hav e a periv asc ular dist ribut ion. Court esy of Andrew F isher, MD.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1901

12 - Liver

F igure 12- 86 Dif f use hepat ic st eat osis. In- phase T 1- w eight ed spoiled gradient ec ho image (A) show s normal hepat ic signal int ensit y . Opposedphase image (B) demonst rat es marked dif f use hepat ic hy point ensit y .

MRI has prov ed t o be a pow erf ul met hod of dif f erent iat ing f oc al f at t y met amorphosis f rom neoplasm. Alt hough areas of marked f at t y c hange may show inc reased signal int ensit y on T 1- w eight ed spin- ec ho images, c onv ent ional spin- ec ho pulse sequenc es are generally insensit iv e f or det ec t ing f at t y met amorphosis (768). How ev er, prot on c hemic al shif t imaging t ec hniques (prot on spec t rosc opic imaging; opposed- phase gradient ec ho imaging) c an readily diagnose f at t y met amorphosis, w het her dif f use or f oc al (272,429,691,711). T hese t ec hniques exploit t he dif f erenc e in resonanc e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1902

12 - Liver f requenc y (3.7 ppm) bet w een prot ons in f at t y ac id molec ules and prot ons in w at er molec ules. If images are obt ained w hen t he f at and w at er prot ons are in- phase, t heir signals are addit iv e; c onv ersely , if images are obt ained w hen t he f at and w at er prot ons are out - of - phase (opposed- phase images), t heir signals c anc el eac h ot her. On opposed- phase images, areas of f at t y met amorphosis appear as regions of dec reased signal int ensit y c ompared w it h t he signal int ensit y of t he same areas on in- phase images (see F ig. 12- 86).

T he pulse sequenc e usually used f or t his purpose is a breat h- hold T 1- w eight ed spoiled gradient ec ho sequenc e. Bec ause t he dif f erenc e in c ont rast bet w een in- phase and opposed- phase images is great est at short T E, w hen imaging at 1.5 T , ec ho t imes of 4.2 msec (in- phase) and 2.1 msec (opposed- phase) should be used (145).

Cirrhosis Cirrhosis is a generalized response of t he liv er t o hepat oc ellular injury and nec rosis c aused by a v ariet y of insult s. T he init ial c ell injury set s up a c y c le of inf lammat ion, regenerat ion, and f ibrosis t hat leads t o alt erat ion of int rahepat ic c irc ulat ion, port al hy pert ension, and c holest asis, leading t o f urt her hepat oc ellular injury and f ibrosis (220). Pat hologic ally , c irrhosis is c harac t erized by ext ensiv e f ibrosis and innumerable regenerat iv e nodules (222). It c an be c lassif ied morphologic ally as mic ronodular (equal- sized nodules of less t han 3 mm in diamet er), mac ronodular (v ariable- sized nodules f rom 3 mm t o sev eral c ent imet ers in diamet er), or mixed (647). On hist ologic examinat ion, t he parenc hy mal nodules are surrounded by c onnec t iv e t issue sept a t hat dist ort and div ide t he normal lobular hepat ic arc hit ec t ure. T he most c ommon c auses of c irrhosis are hepat it is C and B inf ec t ion and exc essiv e alc ohol c onsumpt ion. Ot her c auses inc lude hemoc hromat osis, biliary obst ruc t ion, hepat ic c ongest ion, drugs, t oxins, and heredit ary disorders suc h as Wilson disease, О±1- ant it ry psin def ic ienc y , galac t osemia, and t y pe IV gly c ogen st orage disease (220). T he most import ant c omplic at ions of t he disease are v aric eal bleeding f rom port al hy pert ension, hepat oc ellular c arc inoma, and hepat ic f ailure. T he role of imaging in pat ient s w it h c irrhosis is primarily t o assess liv er size, ev aluat e t he hepat ic v asc ulat ure, ident if y t he ef f ec t s of port al hy pert ension, and det ec t hepat oc ellular c arc inoma. In early c irrhosis t he liv er of t en has a normal appearanc e at CT and MRI. A relat iv ely early sign of c irrhosis is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1903

12 - Liver enlargement of t he hilar periport al spac e, w hic h f ills in w it h inc reased f at t y

t issue due t o at rophy of t he medial segment of t he lef t hepat ic lobe (segment IV) (328). Using a c ut of f v alue of 10 mm, t he report ed sensit iv it y , spec if ic it y , ac c urac y , and posit iv e predic t iv e v alue of t his sign are 93%, 92%, 92%, and 91%, respec t iv ely (328). Ot her early det ec t able c hanges inc lude hepat omegaly and het erogeneit y of hepat ic parenc hy mal at t enuat ion or signal int ensit y due t o t he presenc e of f ibrosis and irregular f at t y c hange. Morphologic f eat ures of adv anc ed c irrhosis inc lude dec reased hepat ic v olume w it h prominenc e of t he int rahepat ic f issures (266,845). Charac t erist ic ally , t he right hepat ic lobe and medial segment of t he lef t lobe are dec reased in size (F ig. 12- 87), w hic h result s in an expanded gallbladder f ossa (327). In many pat ient s t here is a c orresponding inc rease in t he size of t he c audat e lobe and t he lef t lat eral segment (811) (see F ig. 12- 87). Progressiv e at rophy of t he right hepat ic lobe and t he medial segment c orrelat es w it h progression of t he c linic al sev erit y of c irrhosis, w hereas inc reasing size of t he c audat e lobe and t he lat eral segment c orrelat es w it h disease st abilit y (325). An addit ional f inding report ed as a highly spec if ic sign of c irrhosis is a sharp not c h in t he right post erior surf ac e of t he liv er (330). A rat io of t ransv erse c audat e lobe w idt h t o t ransv erse right lobe w idt h has been used t o dist inguish c irrhot ic liv ers P.895 f rom bot h normal and abnormal nonc irrhot ic liv ers (266). T he c audat e lobe is usually measured f rom it s medial aspec t t o t he lat eral aspec t of t he main port al v ein and t he right lobe f rom it s lat eral aspec t t o t he lat eral edge of t he main port al v ein. A c audat e- t o- right lobe rat io of 0.65 or great er has been report ed t o prov ide a sensit iv it y of 84%, a spec if ic it y of 100%, and an ac c urac y of 94% f or t he diagnosis of c irrhosis (266). How ev er, anot her st udy has demonst rat ed t hat alt hough a c audat e- t o- right lobe rat io of great er t han 0.65 is highly spec if ic f or c irrhosis, it s sensit iv it y may be as low as 43% (234). A modif ied c audat e- t o- right lobe rat io, using t he right port al v ein inst ead of t he main port al v ein t o set t he lat eral boundary of t he c audat e lobe, has been show n t o be more ac c urat e f or diagnosing c irrhosis and assessing it s sev erit y (20). In c linic al prac t ic e, how ev er, measured rat ios are rarely used bec ause t he c harac t erist ic alt erat ions in hepat ic morphology seen w it h c irrhosis usually are readily apparent on v isual inspec t ion (80). In addit ion, t he ext ent t o w hic h t he v arious morphologic alt erat ions oc c ur may v ary depending on t he c ause of c irrhosis. Oc c asionally , pat ient s w it h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1904

12 - Liver met ast at ic breast c arc inoma w ho hav e been t reat ed w it h c hemot herapy c an dev elop hepat ic morphology similar t o t hat seen in pat ient s w it h c irrhosis (905) (F ig. 12- 88).

F igure 12- 87 Cirrhosis. Cont rast - enhanc ed CT image show s nodularit y of t he liv er c ont our w it h at rophy of t he medial segment (M) and enlargement of t he lat eral segment (L) of t he lef t hepat ic lobe. Not e t he c harac t erist ic prominent not c h (ar r ow ) in t he right post erior surf ac e of t he liv er.

T he hepat ic c ont our is of t en nodular (see F ig. 12- 87) ow ing t o t he presenc e of regenerat iv e nodules, w hic h usually are similar in at t enuat ion v alue t o normal liv er parenc hy ma. Oc c asionally , how ev er, suc h nodules are hy perat t enuat ing on unenhanc ed CT images due t o t he presenc e of hemosiderin (319) (F ig. 12- 89). Regenerat iv e nodules are more easily apprec iat ed at MRI. T hey usually are isoint ense on bot h T 1- w eight ed (F ig. 1290) and T 2- w eight ed images (559,602), but less c ommonly t hey may be hy perint ense on T 1- w eight ed images, and t hose t hat c ont ain hemosiderin (siderot ic nodules) appear hy point ense on bot h T 1- w eight ed and T 2- w eight ed images (559,602). Bec ause of t heir port al v enous blood supply , regenerat iv e nodules hav e an enhanc ement pat t ern similar t o t hat of normal hepat ic parenc hy ma. T he imaging c harac t erist ic s of t he v arious nodular lesions t hat dev elop in pat ient s w it h c irrhosis are disc ussed in t he sec t ion on hepat oc ellular c arc inoma. T he f ibrous sept a surrounding regenerat iv e nodules appear isoat t enuat ing or hy poat t enuat ing on CT and hy point ense on T 1w eight ed MR images (see F ig. 12- 90). On T 2- w eight ed images t hey hav e int ermediat e signal int ensit y . Het erogeneous enhanc ement of t he hepat ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1905

12 - Liver parenc hy ma is c ommon in pat ient s w it h c irrhosis due t o alt ered hepat ic hemody namic s and morphology .

F igure 12- 88 Pseudoc irrhosis in a pat ient w it h met ast at ic breast c arc inoma t reat ed w it h c hemot herapy . Cont rast - enhanc ed CT show s at rophy of t he right hepat ic lobe and hy pert rophy of t he c audat e and lef t lobes. Capsular ret rac t ion and sc arring delineat e areas of regenerat ion, produc ing an appearanc e t hat resembles mac ronodular c irrhosis.

Approximat ely 15% of pat ient s w it h adv anc ed c irrhosis dev elop c onf luent hepat ic f ibrosis, w hic h appears most c ommonly on unenhanc ed CT as a hy poat t enuat ing w edge- shaped area radiat ing f rom t he port a hepat is t o t he hepat ic periphery (604). Less c ommon c onf igurat ions inc lude peripheral bandlike lesions and t ot al lobar or segment al areas of inv olv ement . Capsular ret rac t ion is usually present . On post c ont rast images t he lesion appears eit her isoat t enuat ing relat iv e t o hepat ic parenc hy ma or, less c ommonly , hy poat t enuat ing (F ig. 12- 91A). At MRI, c onf luent hepat ic f ibrosis demonst rat es morphologic c harac t erist ic s similar t o t hose seen at CT . It is c harac t erist ic ally hy point ense on T 1- w eight ed images (F igs. 12- 91B and 1292A) and hy perint ense on T 2- w eight ed images (605) (F ig. 12- 92B). On early images af t er int rav enous gadolinium administ rat ion, c onf luent hepat ic f ibrosis is usually hy point ense relat iv e t o hepat ic parenc hy ma, but early hy perenhanc ement of c onf luent hepat ic f ibrosis has been report ed (6). On delay ed post c ont rast images, t he f ibrot ic regions may bec ome isoint ense or hy perint ense (F ig. 12- 91C). On superparamagnet ic iron oxide–enhanc ed MRI, c onf luent hepat ic f ibrosis may appear as a w edge- shaped area of high signal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1906

12 - Liver int ensit y w it h int ernal areas of low signal int ensit y , c orresponding t o residual f unc t ioning hepat ic parenc hy ma (513). An addit ional f inding seen in a small perc ent age of pat ient s w it h c irrhosis is

peribiliary c y st s (see F igs. 12- 12 and 12- 13), w hic h result f rom c y st ic dilat ion of obst ruc t ed periduc t al glands (32,322). T heir appearanc e at CT and MRI is desc ribed earlier in t his c hapt er in t he sec t ion on hepat ic c y st s. Ext rahepat ic f eat ures of c irrhosis seen at CT inc lude asc it es, splenomegaly , and port osy st emic c ollat eral v essels (311,519). Port osy st emic c ollat erals appear on CT images as t ort uous t ubular sof t t issue at t enuat ion st ruc t ures t hat enhanc e af t er administ rat ion of int rav enous c ont rast medium (F ig. 1293). On unenhanc ed images t hey may be mist aken f or ly mph nodes (113). On unenhanc ed spin ec ho MR images, port osy st emic c ollat erals usually appear as low signal int ensit y st ruc t ures due t o t he signal v oid produc ed by f low ing blood. On f low - sensit iv e gradient ec ho images, t hey appear as t ubular st ruc t ure w it h high signal int ensit y P.896 due t o inf low ef f ec t s. T hree- dimensional gadolinium- enhanc ed MR angiography is v ery ef f ec t iv e f or mapping port osy st emic c ollat erals f or t reat ment planning (553). Bec ause t iming of t he MR angiography ac quisit ion is c rit ic al t o av oid ov erlap of art erial and v enous st ruc t ures, a t est bolus or bolus t rac king sof t w are should be used t o det ermine t he appropriat e sc an t iming. In addit ion t o anat omic delineat ion w it h c ont rast - enhanc ed 3D imaging, st andard P.897 P.898 2D MR t ec hniques c an prov ide f unc t ional inf ormat ion about t he int rahepat ic and ext rahepat ic v essels, suc h as f low direc t ion and v eloc it y (87,88,180,206,582,737).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1907

12 - Liver

F igure 12- 89 Regenerat iv e nodules. Mult iple peripheral hepat ic nodules (ar r ow heads) appear relat iv ely hy perat t enuat ing prior t o c ont rast medium administ rat ion (A), ow ing t o a c ombinat ion of high iron c ont ent and st eat osis of t he remaining liv er parenc hy ma. T he nodules are isoat t enuat ing during t he hepat ic art erial phase (B) and hy poat t enuat ing during t he port al v enous phase (C ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1908

12 - Liver F igure 12- 90 Cirrhosis. Unenhanc ed (A) and delay ed c ont rast - enhanc ed (B) T 1- w eight ed spoiled gradient ec ho images demonst rat e nodularit y of t he liv er c ont our sec ondary t o innumerable small regenerat iv e nodules. F ibrot ic sept a

surrounding t he regenerat iv e nodules appear hy point ense prec ont rast (A) and hy perint ense on t he delay ed post c ont rast image (B).

F igure 12- 91 Conf luent hepat ic f ibrosis. Cont rast - enhanc ed CT (A) show s a w edge- shaped area of hy poat t enuat ion (ar r ow s) ext ending f rom t he port a hepat is t o t he liv er c apsule. Not e t he slight c apsular ret rac t ion. Unenhanc ed c oronal T 1- w eight ed gradient ec ho MR image (B) show s a w edge- shaped hy point ense area (ar r ow heads) radiat ing f rom t he port a hepat is t o t he dome of t he liv er. On a delay ed gadolinium- enhanc ed image (C ), t he area of f ibrosis has bec ome hy perint ense due t o prolonged ret ent ion of c ont rast mat erial.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1909

12 - Liver

F igure 12- 92 Conf luent hepat ic f ibrosis. A T 1- w eight ed spin- ec ho MR image (A) show s t w o areas of peripheral hy point ensit y in t he right hepat ic lobe (F ). Not e ret rac t ion of t he ov erly ing liv er c apsule. On a T 2- w eight ed spin- ec ho image (B), t he areas of f ibrosis are mildly hy perint ense.

F igure 12- 93 Cirrhosis w it h port osy st emic c ollat eral v eins. Cont rast enhanc ed CT (A) and T 1- w eight ed spoiled gradient ec ho MR (B) images show nodularit y of t he hepat ic c ont our w it h hy pert rophy of t he c audat e and lef t hepat ic lobes. Splenomegaly and port osy st emic c ollat eral v eins (ar r ow heads) are indic at iv e of port al v enous hy pert ension.

Iron Overload Exc ess iron generally ent ers t he body by one of t w o primary pat hw ay s: inc reased gast roint est inal absorpt ion or int rav enous blood t ransf usion (736). Examples of c ondit ions t hat result f rom long- t erm inc reased int est inal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1910

12 - Liver absorpt ion of iron are genet ic hemoc hromat osis and ery t hropoet ic hemoc hromat osis. In t hese c ondit ions, iron deposit s w it hin t he parenc hy mal c ells of t he liv er and ot her organs (inc luding panc reas, gast roint est inal t rac t , kidney s, heart , and endoc rine glands) w it h result ing organ damage (650).

T ransf usional iron ov erload is due t o repeat ed parent eral administ rat ion of red blood c ells result ing in deposit ion of exc ess iron in t he ret ic uloendot helial c ells of t he liv er, spleen, and bone marrow (736). Hemoc hromat osis is c at egorized as primary or sec ondary . Primary (genet ic ) hemoc hromat osis is an HLA- linked inherit ed disorder in w hic h a muc osal def ec t in t he int est inal w all leads t o inc reased absorpt ion of ingest ed iron (650). It usually present s in t he f ourt h or f if t h dec ade. Init ial manif est at ions may inc lude diabet es mellit us, hy perpigment at ion, and nonspec if ic abdominal sy mpt oms (220). Hepat omegaly , oc c urring in 90% of pat ient s, is t he most c ommon phy sic al f inding. Most pat ient s go on t o dev elop hepat ic f ibrosis or c irrhosis, and 14% t o 30% of pat ient s ev ent ually dev elop hepat oc ellular c arc inoma as a lat e c omplic at ion of t he disease (63,869). How ev er, hepat oc ellular c arc inoma dev elops only rarely if t he disease is t reat ed in t he prec irrhot ic st age (651,652). Wide- ranging endoc rine dy sf unc t ion is c ommon, espec ially in y ounger pat ient s. Cardiac inv olv ement , seen in approximat ely 15% of pat ient s, is manif est as arrhy t hmias and c ongest iv e heart f ailure (60). Alt hough t he mean surv iv al af t er diagnosis w as only 4.4 y ears in 1935 (205), t he surv iv al of pat ient s w it h hemoc hromat osis has inc reased subst ant ially sinc e t hen due t o improv ed det ec t ion t ec hniques and met hods of t reat ment . Of pat ient s t reat ed by phlebot omy , 89% now hav e a 5- y ear surv iv al rat e f rom t he t ime of diagnosis (869). Sec ondary hemoc hromat osis is seen most c ommonly in pat ient s w it h disorders of inef f ec t iv e ery t hropoiesis suc h as t halassemia. In ery t hropeoiet ic hemoc hromat osis, t he inc reased demand f or iron f rom ery t hroc y t e prec ursors in t he bone marrow result s in inc reased absorpt ion of iron, w hic h get s deposit ed in parenc hy mal c ells (736). T he age of present at ion of t en is earlier t han in pat ient s w it h primary hemoc hromat osis, but t he c linic al and imaging f indings are t he same. T ransf usional iron ov erload oc c urs in pat ient s w ho undergo mult iple blood t ransf usions. T he iron f rom t he t ransf used ery t hroc y t es pref erent ially deposit s in t he ret ic uloendot helial c ells of t he liv er, spleen, and bone marrow . If t he iron st orage c apac it y of t he ret ic uloendot helial sy st em is exc eeded, how ev er,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1911

12 - Liver iron t hen deposit s in t he parenc hy mal c ells and c an result in organ damage (736).

F igure 12- 94 Hemoc hromat osis. T he at t enuat ion v alue of t he liv er is dif f usely inc reased due t o parenc hy mal iron ov erload.

P.899 CT c an prov ide a noninv asiv e diagnosis of hepat ic iron ov erload. Pat ient s w it h moderat e or marked hepat ic iron ov erload display homogeneously inc reased hepat ic x- ray at t enuat ion on unenhanc ed CT images (F ig. 12- 94). Hepat ic parenc hy mal at t enuat ion v alues of 70 HU or great er are c harac t erist ic ally seen in pat ient s w it h iron ov erload, c ompared w it h 45 t o 65 HU f or normal unenhanc ed liv er parenc hy ma (111,256,291). A linear relat ionship bet w een CT at t enuat ion v alues and hepat ic iron c ont ent has been demonst rat ed using bot h c onv ent ional single- energy CT sc anning at 120 kVp (291) and dualenergy CT sc anning (107,239). How ev er, one st udy (256) report ed a sensit iv it y of only 63% f or t he diagnosis of hepat ic iron ov erload w it h t he use of single- energy CT . T hus, t he f inding of normal liv er at t enuat ion v alues does not exc lude t he possibilit y of iron ov erload. In some c ases, c oexist ent f at t y c hange in t he liv er may reduc e t he hepat ic CT at t enuat ion v alue, t hus low ering t he sensit iv it y of CT f or t he diagnosis, part ic ularly in obese pat ient s or in t hose w it h diabet es or alc oholic liv er disease (291). Bec ause iron has a high at omic number, reduc ing t he sc anning energy t o 80 kVp result s in a marked inc rease in hepat ic at t enuat ion if exc ess iron is present in t he liv er. T hus sc anning at reduc ed kVp c an help est ablish t he diagnosis of iron ov erload if t he hepat ic at t enuat ion v alue at 120 kVp is borderline (34). It should be

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1912

12 - Liver

kept in mind t hat high hepat ic parenc hy mal at t enuat ion v alues are not spec if ic f or iron ov erload and c an be seen in pat ient s w it h gly c ogen st orage disease (173), Wilson disease (517), pat ient s being t reat ed w it h t he c ardiac ant iarrhy t hmic agent amiodarone (241) (F ig. 12- 95), and some pat ient s w ho are on hy peraliment at ion. In addit ion, prev ious administ rat ion of t horium dioxide (T horot rast ) c auses a c harac t erist ic inc rease in hepat ic and splenic at t enuat ion v alues (669).

F igure 12- 95 Hepat ic iodine deposit ion in a pat ient t reat ed w it h amiodarone. T he at t enuat ion v alue of t he liv er is dif f usely inc reased. T he appearanc e is indist inguishable f rom t hat of hepat ic iron ov erload.

MRI is v ery sensit iv e f or det ec t ing c linic ally signif ic ant hepat ic iron ov erload and show s a dramat ic reduc t ion in t he hepat ic signal int ensit y in pat ient s w it h exc ess iron deposit ion, regardless of t he c ause (75,700,768,770) (F igs. 12- 96 and 12- 97). F urt hermore, t he low hepat ic signal int ensit y demonst rat ed at MRI is more spec if ic f or t he diagnosis of iron ov erload t han t he high at t enuat ion show n by CT . T he MR f indings usually are dif f use but rarely c an be f oc al or segment al (348,368,563). T he signal alt erat ion is due t o t he paramagnet ic ef f ec t of t he int rac ellular iron, w hic h c auses adjac ent w at er prot ons t o lose phase c oherenc e, result ing in signal loss. T he dec reased signal int ensit y of t he hepat ic parenc hy ma result s f rom t he magnet ic susc ept ibilit y ef f ec t s of iron, w hic h are best seen on T 2- w eight ed or T 2* - w eight ed images (646).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1913

12 - Liver

F igure 12- 96 Sec ondary hemoc hromat osis. T 1- w eight ed MR image show s marked dif f use hy point ensit y of t he liv er and spleen.

F igure 12- 97 Primary hemoc hromat osis. T 2- w eight ed MR image w it h f at suppression show s marked dif f use hy point ensit y of t he liv er and panc reas (ar r ow heads).

P.900 In many c ases, hepat ic parenc hy mal iron ov erload c an be dist inguished f rom ret ic uloendot helial iron ov erload, based on rec ognit ion of ext rahepat ic signal int ensit y c hanges (734,893). In ret ic uloendot helial c ell iron ov erload, t he liv er and spleen bot h hav e low signal int ensit y (see F ig. 12- 96), and low signal int ensit y also c an be seen in t he bone marrow . How ev er, in pat ient s w it h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1914

12 - Liver parenc hy mal c ell iron ov erload, t he splenic and bone marrow signal int ensit ies are not alt ered but low signal int ensit y c an be seen in t he panc reas (see F ig. 12- 97). In pat ient s w it h idiopat hic (genet ic ) hemoc hromat osis, low signal int ensit y of t he panc reas is assoc iat ed w it h t he presenc e of c irrhosis (735). St udies hav e show n good c orrelat ion bet w een in v iv o T 2 or T 2* relaxat ion measurement s and iron c onc ent rat ions in hepat ic biopsy samples (58,129,188,229,243,625,838). Gradient ec ho sequenc es are more sensit iv e t han spin- ec ho sequenc es f or demonst rat ing mild degrees of hepat ic iron ov erload (646) and are more ac c urat e f or t he est imat ion of hepat ic iron

c onc ent rat ion (58). Qualit at iv e ev aluat ion of liv er iron deposit ion c an be done by c omparing t he signal int ensit y of t he liv er w it h t hat of t he adjac ent paraspinal musc le. Iron ov erload should be c onsidered if t he signal int ensit y of t he liv er is less t han t hat of t he paraspinal musc les, w hic h are not af f ec t ed by iron ov erload (145).

Hepatitis Hepat it is is an inf lammat ory proc ess, eit her ac ut e or c hronic , inv olv ing t he liv er dif f usely . Viral inf ec t ion is t he most c ommon c ause, but nonv iral inf ec t ions and injury f rom inhalat ion, ingest ion, or parent eral administ rat ion of v arious agent s also c an result in hepat it is. Hist ologic ally , t he ac ut e f orm is c harac t erized by hepat oc ellular nec rosis and degenerat ion w it hout assoc iat ed port al or periport al abnormalit ies. Chronic hepat it is c an be c lassif ied as eit her persist ent or ac t iv e (157). In c hronic persist ent hepat it is, periport al inf lammat ion is present w it hout disrupt ion of hepat ic lobular arc hit ec t ure, w hereas c hronic ac t iv e hepat it is is assoc iat ed w it h more ext ensiv e inf lammat ion, nec rosis, and f ibrosis (157). T he primary role of CT and MRI in pat ient s w it h hepat it is is t o ident if y hepat oc ellular c arc inoma. T he imaging f indings of hepat it is are nonspec if ic . Wit h ac ut e hepat it is, c ommon CT f indings inc lude hepat omegaly , dif f use st eat osis, gallbladder w all t hic kening (F ig. 12- 98), and hepat ic periport al luc enc y due t o edema. MRI f indings in hepat it is inc lude periport al hy perint ensit y due t o edema on T 2- w eight ed images (331,509) and prolongat ion of hepat ic T 1 and T 2 relaxat ion (768). In pat ient s w it h c hronic hepat it is, gadolinium- enhanc ed MR imaging f indings may be able t o dist inguish bet w een pat ient s w it h f ibrosis and t hose w it h c onc urrent or rec ent hepat oc ellular damage. Approximat ely 70% of pat ient s w ho demonst rat e pat c hy areas of hepat ic enhanc ement on early post c ont rast images hav e liv er

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1915

12 - Liver inf lammat ion on hist opat hologic examinat ion. Ninet y - f iv e perc ent (95%) of pat ient s w ho demonst rat e linear hepat ic enhanc ement on lat e post c ont rast images hav e f ibrosis on hist opat hology (725). Wit h c hronic ac t iv e hepat it is, ly mphadenopat hy in t he port a hepat is, gast rohepat ic ligament , and ret roperit oneum c an be ident if ied in t he majorit y of pat ient s (247) (see F ig. 12- 84). Change in ly mph node size ov er t ime c an be used t o assess t he response t o immunosuppressiv e t herapy in t hese pat ient s (247). T here is also a c orrelat ion bet w een disease ac t iv it y and t he

number, size and signal int ensit y of perihepat ic ly mph nodes seen at MRI. In a st udy of 50 pat ient s w it h c hronic ac t iv e hepat it is C, t hose w it h mild disease ac t iv it y had an av erage of 2.5 perihepat ic ly mph nodes, w it h an av erage diamet er of 1.5 c m, and an av erage of 0.17 hy perint ense nodes on f at suppressed T 2- w eight ed images. Pat ient s w it h sev ere disease ac t iv it y had an av erage of 8.3 perihepat ic nodes, w it h an av erage diamet er of 4.9 c m, and an av erage of 2.4 hy perint ense nodes (911).

Radiation Injury Radiat ion- induc ed hepat ic injury f rom ext ernal beam ionizing radiat ion c an oc c ur in pat ient s w ho hav e rec eiv ed eit her a single dose of approximat ely 1400 rad (14 Gy ) or a 6- w eek f rac t ionat ed dose of 3500 rad (35 Gy ) or great er (198,338). Hist ologic examinat ion w it hin 60 day s of hepat ic irradiat ion demonst rat es sinusoidal c ongest ion, hy peremia, or hemorrhage w it h some at rophy of c ent ral hepat oc y t es (198). CT perf ormed w it hin sev eral mont hs af t er radiat ion t herapy demonst rat es a sharply def ined band of hy poat t enuat ion in t he liv er, c orresponding t o t he radiat ion port (F ig. 12- 99). T he hy poat t enuat ion result s f rom regional hepat ic c ongest ion and/or f at t y met amorphosis. Ov er a period of w eeks, t he init ially sharp borders of t he zone may bec ome more irregular as peripheral areas of parenc hy ma regenerat e (45). T he abnormal CT appearanc e of t en resolv es c omplet ely af t er sev eral mont hs (338,393,817). T he irradiat ed area may ev ent ually bec ome at rophic .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1916

12 - Liver

F igure 12- 98 Hepat it is. Cont rast - enhanc ed CT images (A, B) show hepat omegaly w it h mild dif f use st eat osis and gallbladder w all t hic kening.

P.901 High- dose radiat ion t herapy of malignant hepat ic t umors using ov erlapping port als (c onf ormal radiat ion t herapy ) may result in an area of hy poat t enuat ion adjac ent t o t he t reat ed t umor in t he t arget v olume (884). T he appearanc e dif f ers f rom t hat seen af t er c onv ent ional ext ernal beam radiat ion t herapy in t hat it does not hav e a sharp, st raight int erf ac e w it h t he nonirradiat ed liv er. Maximal ef f ec t is seen 2 t o 3 mont hs af t er c omplet ion of t herapy and persist s f or up t o 3 mont hs. An ov al- shaped area of hepat ic hy poat t enuat ion has been report ed af t er prot on radiot herapy of hepat oc ellular c arc inoma (611).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1917

12 - Liver F igure 12- 99 Radiat ion- induc ed hepat ic injury . Cont rast - enhanc ed CT show s

a sharply delineat ed region of hepat ic hy poat t enuat ion (ar r ow heads) near t he dome of t he liv er in a pat ient w ho had rec eiv ed ext ernal beam radiat ion t herapy f or lung c arc inoma.

An unusual peripheral band of hepat ic radiat ion injury adjac ent t o t he right abdominal w all has been report ed in pat ient s t reat ed f or mesot helioma w it h int ensit y - modulat ed radiat ion t herapy (557). T he CT appearanc e c onsist s of a hy poat t enuat ing band at t he periphery of t he liv er af t er c ont rast medium administ rat ion. At MRI, t he band is primarily hy point ense on T 2- w eight ed images w it h small nodular areas of hy perint ensit y . On gadolinium- enhanc ed T 1- w eight ed images t he nodular areas show c ont rast enhanc ement , w hic h c ould be misint erpret ed as met ast at ic disease. In t he majorit y of pat ient s, t he liv er abnormalit y ret urns t o normal ov er a period of mont hs (557). MRI in pat ient s w it h radiat ion- induc ed hepat ic injury demonst rat es hy point ensit y in t he af f ec t ed port ions of t he liv er on T 1- w eight ed images and hy perint ensit y on T 2- w eight ed images, ow ing t o inc reased w at er c ont ent in t he irradiat ed areas (614,817). Dy namic gadolinium- enhanc ed images show early and prolonged hy perint ense enhanc ement of t he radiat ion injured port ion of t he liv er (614). Superparamagnet ic iron oxide enhanc ed MR imaging has been show n t o be usef ul f or ident if y ing areas of radiat ion- induc ed liv er injury based on t he experiment al f inding t hat irradiat ed liv er c ont ains f ew er and less ef f ec t iv e Kupf f er c ells (132,493,783). Af t er administ rat ion of superparamagnet ic iron oxide, t he irradiat ed liv er appears hy perint ense due t o abnormally low upt ake of t he c ont rast agent (620,904).

Sarcoidosis Sarc oidosis is a generalized granulomat ous disease of unknow n et iology t hat most c ommonly inv olv es t he pulmonary parenc hy ma and t he mediast inal and hilar ly mph P.902 nodes. In 24% t o 79% of pat ient s, nonc aseat ing granulomas of v ariable size c an be ident if ied in t he liv er on hist ologic examinat ion (278,435,494), and approximat ely t he same perc ent age of pat ient s hav e splenic inv olv ement (719,789). How ev er, t he signs and sy mpt oms of hepat osplenic inv olv ement rarely dominat e t he c linic al pic t ure (518). T he most c ommon c linic al manif est at ion of hepat ic sarc oidosis is hepat omegaly , seen in 20% t o 38% of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1918

12 - Liver pat ient s (79,518). Rarely , hepat ic sarc oidosis may result in jaundic e (478), presinusoidal port al hy pert ension (535,649), or hepat ic f ailure (578,579,649). T he most c ommon abdominal CT f indings in pat ient s w it h hepat osplenic sarc oidosis inc lude homogeneous hepat ic and splenic enlargement (854). Disc ret e hy poat t enuat ing nodules, ranging f rom sev eral millimet ers t o 2 c m in diamet er, c an be ident if ied in t he liv er and spleen in 5% t o 19% and 15% t o 33% of pat ient s, respec t iv ely (79,851,853) (F ig. 12- 100). Rarely , lesions may bec ome c onf luent and measure up t o 6 c m (346). On MR images, t he nodules

are hy point ense relat iv e t o bac kground hepat ic and splenic parenc hy ma on all pulse sequenc es, and t hey show no subst ant ial enhanc ement af t er IV administ rat ion of gadolinium- c helat e (208,377,852). Af t er superparamagnet ic iron oxide administ rat ion, how ev er, t hey appear hy perint ense relat iv e t o liv er parenc hy ma (402). Abdominal ly mphadenopat hy is anot her c ommon manif est at ion on CT and MR images, w it h t he port a hepat is, c eliac axis, and paraaort ic /parac av al nodes being inv olv ed most f requent ly (79,851). Abdominal CT f indings appear t o c orrelat e w it h disease ac t iv it y but not w it h c hest radiographic st age (851). In an indiv idual pat ient , t he abdominal CT manif est at ions of sarc oidosis may be dif f ic ult t o dist inguish f rom t hose of nonHodgkin ly mphoma (79).

F igure 12- 100 Sarc oidosis. Cont rast - enhanc ed CT show s mult iple small hy poat t enuat ing nodules t hroughout t he liv er and spleen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1919

12 - Liver Storage Disorders T he imaging f indings in st orage disorders af f ec t ing t he liv er usually are nonspec if ic , most c ommonly result ing in hepat omegaly w it h or w it hout assoc iat ed st eat osis. Wit h long- st anding disease, pat ient s w it h some st orage disorders may go on t o dev elop port al hy pert ension and c irrhosis. On CT images, t he liv er of pat ient s w it h gly c ogen st orage or Wilson disease may be hy perat t enuat ing, due t o t he inc reased x- ray at t enuat ion of deposit ed gly c ogen and c opper, respec t iv ely (173,517). How ev er, most inv est igat ors hav e f ound no c orrelat ion bet w een CT at t enuat ion v alues and hepat ic c opper c onc ent rat ion (160,749). F urt hermore, in pat ient s w it h gly c ogen st orage

disease, t he liv er more c ommonly is eit her normal or low in at t enuat ion, due t o t he hy poat t enuat ing ef f ec t of t he assoc iat ed st eat osis (F ig. 12- 101) (52,164). Hepat ic adenomas are c ommon in pat ient s w it h gly c ogen st orage disease t y pes I (v on Gierke disease) and III (see F ig. 12- 101), and malignant degenerat ion int o hepat oc ellular c arc inoma has been report ed (51,214,292,374,570). In one st udy , 52% of pat ient s w it h t y pe I and 25% of pat ient s w it h t y pe III gly c ogen st orage disease w ere f ound t o hav e adenomas (415). T he durat ion bet w een t he diagnosis of liv er adenomas and t he diagnosis of hepat oc ellular c arc inoma has ranged f rom 0 t o 28 y ears, and serum alphaf et oprot ein lev el is normal in t he majorit y of pat ient s (214). Consequent ly , pat ient s w it h gly c ogen st orage disease, part ic ularly t hose w it h v on Gierke disease, generally undergo periodic imaging examinat ions t o assess f or rapid grow t h or ot her c hanges in t he appearanc e of adenomas t hat might suggest malignant degenerat ion. Inv est igat ors perf orming MR spec t rosc opy of c opper ions in saline solut ion hav e observ ed a c onc ent rat ion- dependent short ening of T 1 relaxat ion (700). How ev er, MRI in pat ient s w it h Wilson disease has f ailed t o demonst rat e alt erat ions in P.903 hepat ic T 1 relaxat ion or in hepat ic signal int ensit y on eit her T 1- or T 2w eight ed images (167,424,567).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1920

12 - Liver

F igure 12- 101 Gly c ogen st orage disease. Cont rast - enhanc ed CT show s hepat omegaly w it h mild dif f use st eat osis. Not e t w o small hepat oc ellular adenomas (ar r ow s) in t he right lobe.

T he most c ommon hepat ic f inding in pat ient s w it h Gauc her disease is hepat omegaly (423). In addit ion, 20% of pat ient s w it h Gauc her disease demonst rat e st ellat e or segment al areas of f oc al hepat ic signal abnormalit ies t hat are hy point ense relat iv e t o normal liv er parenc hy ma on T 1- w eight ed images and hy perint ense on T 2- w eight ed images (280). T hese f oc al hepat ic abnormalit ies hav e been at t ribut ed t o f ibrot ic sept a w it h isc hemic c hanges assoc iat ed w it h aggregat es of Gauc her c ells (280).

Other Diffuse Disorders Amy loidosis is c harac t erized by abnormal ext rac ellular deposit ion and ac c umulat ion of prot ein and prot ein deriv at iv es. Alt hough t he liv er is c ommonly inv olv ed, t he imaging appearanc e is nonspec if ic (232). Hepat omegaly and dif f usely dec reased hepat ic at t enuat ion at CT hav e been report ed (232). Dif f usely inc reased hepat ic parenc hy mal at t enuat ion v alue, indist inguishable f rom t he CT appearanc e of hepat ic iron ov erload, c an be seen in pat ient s t reat ed w it h t he c ardiac ant iarrhy t hmic agent amiodarone (see F ig. 12- 82). T he inc rease in hepat ic parenc hy mal at t enuat ion v alue, w hic h c an be seen

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1921

12 - Liver ev en in pat ient s on short - t erm t herapy (279), is due t o ac c umulat ion w it hin hepat oc y t es of t he drug or it s met abolit es t hat c ont ain iodine (241,490). In pat ient s w ho hav e rec eiv ed t horium dioxide (T horot rast ), CT demonst rat es

high at t enuat ion of t he liv er, spleen, and regional ly mph nodes (669,738). T he liv er may appear dif f usely and homogeneously dense, but usually it has an irregular or ret ic ular pat t ern of inc reased at t enuat ion. T horium dioxide–induc ed hepat ic neoplasms are seen as hy poat t enuat ing masses replac ing areas of t he hy perat t enuat ing liv er parenc hy ma (452). Gold f rom preparat ions injec t ed t o t reat rheumat oid art hrit is c an ac c umulat e in t he ret ic uloendot helial sy st em and c ause dif f usely inc reased hepat ic parenc hy mal densit y (153). In addit ion, pat ient s t reat ed w it h c isplat in w ho are imaged w it h CT immediat ely af t er t herapy may hav e dif f usely inc reased hepat ic at t enuat ion v alues, w hic h ret urn t o normal w it hin a mont h af t er t reat ment (7).

VASCULAR DISORDERS Portal Vein Thrombosis Port al v ein t hrombosis is t he major c ause of presinusoidal hy pert ension in t he Unit ed St at es (220). In t he adult populat ion, c ommon c auses inc lude panc reat it is, asc ending c holangit is, propagat ion of splenic v ein t hrombus af t er splenec t omy (303,871), st asis assoc iat ed w it h c irrhosis, and neoplasm (hepat ic , biliary , panc reat ic , or gast ric ). Less c ommon c auses inc lude hy perc oagulable st at es, t rauma, int ra- abdominal inf ec t ion, and inf lammat ion. Inv olv ement may be part ial or c omplet e and may inv olv e any port ion of t he port al v enous sy st em. Clinic al diagnosis is of t en dif f ic ult as c linic al signs and sy mpt oms are nonspec if ic .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1922

12 - Liver

F igure 12- 102 Port al v ein t hrombosis. Cont rast - enhanc ed CT image show s enlargement and lac k of enhanc ement of t he main right port al v ein (ar r ow ) and peripheral right port al v ein branc hes (ar r ow heads). Not e t he t ransient hepat ic at t enuat ion dif f erenc e (T HAD) result ing in inc reased at t enuat ion of t he right hepat ic lobe.

T he CT diagnosis of port al v ein t hrombosis is best made af t er bolus administ rat ion of int rav enous c ont rast mat erial. Post c ont rast images demonst rat e a f illing def ec t inc omplet ely or c omplet ely f illing t he port al v ein lumen (F ig. 12- 102). Enhanc ement of t he w all of t he port al v ein c an be ident if ied w it h c omplet e t hrombosis, likely due t o f low t hrough dilat ed v asa v asorum, but a small amount of blood f low around an inc omplet ely oc c luding t hrombus c an hav e a similar appearanc e. St reaky or dif f use enhanc ement w it hin t he obst ruc t ed port al v ein indic at es t he presenc e of t umor t hrombus (495). When t hrombosis is ac ut e, t he port al v ein c ont ent s may be high in at t enuat ion on prec ont rast images (546). Wit h c hronic port al v ein t hrombosis, numerous small periport al c ollat eral v eins (c av ernous t ransf ormat ion) are of t en ident if ied (F igs. 12- 103 and 12- 104). Port osy st emic c ollat eral v eins may dev elop as a c onsequenc e of port al v enous hy pert ension (593). Indirec t CT signs of port al v ein t hrombosis are relat ed t o alt erat ions in hepat ic blood supply . Dec reased hepat ic lobar at t enuat ion on prec ont rast images is post ulat ed t o be due t o hepat ic gly c ogen deplet ion and inc reased hepat oc y t e f at c ont ent relat ed t o loss of nut rient s and insulin normally supplied by t he port al v enous c irc ulat ion (165). T w o f low - relat ed phenomena t hat c an be seen during dy namic c ont rast - enhanc ed imaging are diminished hepat ic parenc hy mal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1923

12 - Liver enhanc ement during t he port al v enous phase and inc reased parenc hy mal enhanc ement during t he lat e hepat ic art erial phase (see F ig. 12- 102). Diminished enhanc ement during t he port al v enous phase is due t o loc ally dec reased port al v enous perf usion (495); t ransient ly inc reased segment al or lobar enhanc ement seen during t he lat e hepat ic art erial phase is P.904 due t o inc reased hepat ic art erial f low t o a segment or lobe in w hic h port al v enous f low is diminished (314,318). T he lat t er phenomenon is ref erred t o as t ransient hepat ic at t enuat ion dif f erenc e (T HAD). In c ases of port al v ein t hrombosis, t he inc reased hepat ic art erial blood f low oc c urs mainly t hrough

t he peribiliary plexus (323). Alt hough int rahepat ic port al v ein t hrombosis is t he most c ommon c ause of T HAD, t hrombosis need not be present , as inc reased int rahepat ic pressure f rom any c ause t hat result s in diminished port al v enous f low c an produc e t he same CT f inding (165). Obst ruc t ion or c ompression of peripheral port al v ein branc hes by an int rahepat ic t umor is a c ommon c ause of T HAD (382). Addit ional c auses of T HAD inc lude art erioport al shunt ing (t umor relat ed and non- t umor relat ed) (F ig. 12- 105), early ret urn t o t he liv er of sy st emic v enous blood f rom aberrant v enous drainage, and hy peremia sec ondary t o an absc ess, ac ut e c holec y st it is, or c holangit is (109,126,323). A segment or lobe of t he liv er af f ec t ed by c hronic ally dec reased port al v enous f low may undergo at rophy ov er t ime (590). An addit ional indirec t sign of port al v ein obst ruc t ion is art erioport al shunt ing, w hic h appears as early enhanc ement of t he inv olv ed port al v ein branc h during t he art erial phase of enhanc ement (316,505,572).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1924

12 - Liver F igure 12- 103 Cav ernous t ransf ormat ion of t he port al v ein. Maximum int ensit y projec t ion (MIP) image f rom a c ont rast - enhanc ed CT examinat ion show s a t angle of c ollat eral v essels (ar r ow s) t hat hav e f ormed in t he port a hepat is af t er t hrombosis of t he main port al v ein. T he splenomegaly is due t o sec ondary port al hy pert ension.

F igure 12- 104 Cav ernous t ransf ormat ion of t he port al v ein. T ransaxial (A) and c oronal (B) maximum int ensit y projec t ion (MIP) images f rom a gadoliniumenhanc ed T 1- w eight ed spoiled gradient ec ho MR ac quisit ion show a t angle of periport al c ollat eral v essels (ar r ow s) in t he port a hepat is.

MRI is an exc ellent means of demonst rat ing port al v ein t hrombosis bec ause of t he nat ural c ont rast produc ed by f low ing blood (206,453,737). On spin- ec ho images, int raluminal signal t hat c annot be at t ribut ed t o f low - relat ed art if ac t is suggest iv e of t hrombosis. How ev er, it may be dif f ic ult t o dist inguish bet w een port al v ein signal due t o t hrombosis and t hat due t o sluggish f low , on t he basis of spin- ec ho images alone. F low - sensit iv e gradient ec ho images are helpf ul in est ablishing t he diagnosis (739). How ev er, t hree- dimensional c ont rast - enhanc ed MR angiography , w hic h ov erc omes some of t he limit at ions of nonc ont rast MR angiography , is t he best MR t ec hnique f or ident if y ing v enous t hrombosis. Sensit iv it ies of 98% t o 100%, spec if ic it ies of 98% t o 99%, and ac c urac ies of 98% t o 99% hav e been report ed f or 3D MR angiography in det ec t ing bot h bland and t umor t hrombus in t he port al v enous sy st em (403,468). Wit h t his t ec hnique, how ev er, art if ac t s relat ed P.905 t o t urbulent f low c an simulat e port al v ein t hrombosis in a small perc ent age of pat ient s, mainly t hose w it h c irrhosis (589). Ident if ic at ion of periport al c ollat eral v essels support s t he diagnosis of port al v ein t hrombosis (453,868).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1925

12 - Liver T umor t hrombus and bland t hrombus c an be dist inguished based on t he f ollow ing observ at ions: t umor t hrombus is higher in signal int ensit y on T 2w eight ed images, is int ermediat e in signal int ensit y on t ime of f light images, and enhanc es af t er gadolinium administ rat ion, w hereas bland t hrombus is low

in signal int ensit y on bot h T 2- w eight ed and t ime of f light images and does not demonst rat e c ont rast enhanc ement (549).

F igure 12- 105 T ransient hepat ic int ensit y dif f erenc e (T HID) c aused by art erioport al shunt ing in a pat ient w it h c irrhosis. Art erial phase maximum int ensit y projec t ion (MIP) image (A) f rom a gadolinium- enhanc ed T 1- w eight ed MR ac quisit ion show s a w edge- shaped area of peripheral enhanc ement (ar r ow s) in t he ant erior segment of t he right hepat ic lobe w it h early drainage int o a port al v ein branc h (ar r ow head). A c oronal art erial phase rec onst ruc t ion (B) show s similar f indings inc luding early drainage int o t he right port al v ein (ar r ow head).

Int rahepat ic port al v ein oc c lusion c an produc e segment al or lobar signal int ensit y abnormalit ies, appearing as w edge- shaped areas t hat are hy point ense on T 1- w eight ed images and hy perint ense on T 2- w eight ed images (235,320). Oc c asionally , iron deposit ion c an be ident if ied as segment al or lobar hy point ense areas on gradient ec ho images (348). In addit ion, t ransient segment al or lobar hy perenhanc ement (t ransient hepat ic int ensit y dif f erenc e or T HID), similar t o t hat seen on c ont rast - enhanc ed CT , c an be seen w it h dy namic gadolinium- enhanc ed MRI (F ig. 12- 106).

Budd-Chiari Syndrome T he Budd- Chiari sy ndrome is a rare disorder t hat result s f rom obst ruc t ion t o hepat ic v enous out f low , at t he lev el of eit her t he large hepat ic v eins or t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1926

12 - Liver inf erior v ena c av a. In t he ac ut e f orm of t he disease, pat ient s c harac t erist ic ally present w it h abdominal pain, t ender hepat omegaly , and asc it es. How ev er, w it h t he subac ut e or c hronic f orms, t he c linic al

present at ion may be insidious and t he diagnosis dif f ic ult t o make. Alt hough t he majorit y of c ases are idiopat hic , a number of spec if ic c auses are rec ognized inc luding hy perc oagulable st at es (part ic ularly poly c y t hemia v era and oral c ont rac ept iv e use), neoplasms (part ic ularly hepat oc ellular c arc inoma, renal c ell c arc inoma, and adrenoc ort ic al c arc inoma), c hronic leukemia, t rauma, pregnanc y , and w ebs and membranes inv olv ing t he inf erior c av a and/or hepat ic v eins (564). T he obst ruc t ion t o hepat ic v enous out f low result s in sev ere c ent rilobular c ongest ion w it h inc reased sinusoidal pressure, leading t o delay ed or rev ersed port al v enous inf low . T he regional dist urbanc es in port al v enous f low are primarily responsible f or t he c harac t erist ic f indings at c ont rast - enhanc ed CT and MRI (15,547,821). In pat ient s w it h long- st anding Budd- Chiari sy ndrome, progressiv e enlargement of t he hepat ic art ery may lead t o a c ompensat ory inc rease in hepat ic art erial perf usion (99). When Budd- Chiari sy ndrome oc c urs ac ut ely , nonc ont rast CT demonst rat es global hepat ic enlargement w it h dif f use hepat ic hy poat t enuat ion, due t o hepat ic parenc hy mal c ongest ion (498). Asc it es is usually present , and hy perat t enuat ing t hrombi may be ident if ied in t he inf erior v ena c av a or hepat ic v eins (498,547). Dy namic c ont rast - enhanc ed CT show s pat c hy hepat ic parenc hy mal enhanc ement w it h poor v isualizat ion of t he hepat ic v eins (F ig. 12- 107). In some c ases t he c ent ral port ions of t he liv er, inc luding t he P.906 c audat e lobe, enhanc e relat iv ely normally and appear hy perat t enuat ing relat iv e t o t he peripheral liv er parenc hy ma, w hic h enhanc es poorly (268,498). More delay ed images may show gradual spreading of t he pat c hy c ent ral enhanc ement t ow ard t he periphery or a rev ersal of t he earlier pat t ern, w it h relat iv e hy perat t enuat ion of t he peripheral liv er parenc hy ma (268,498,821,839). In ot her c ases, t he ent ire liv er demonst rat es a het erogeneous parenc hy mal enhanc ement pat t ern. Int rav asc ular t hrombi may be ident if ied as hy poat t enuat ing masses w it hin t he hepat ic v eins or inf erior v ena c av a (498,547,839). Hepat ic inf arc t s, appearing as nonenhanc ing peripheral w edge- shaped regions, are oc c asionally present . T he inf erior v ena c av a is of t en narrow ed (see F ig. 12- 107) or oc c luded, and assoc iat ed dilat ed c ollat eral v eins may be present (26). Conc omit ant port al v ein t hrombosis is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1927

12 - Liver

present in up t o 20% of pat ient s w it h Budd- Chiari sy ndrome (839). In pat ient s w it h c hronic v enous oc c lusion, t he c audat e lobe is of t en enlarged relat iv e t o t he remainder of t he at rophied liv er, ow ing t o sparing of t he c audat e lobe v enous out f low , w hic h drains direc t ly int o t he inf erior v ena c av a. T he hepat ic v eins are usually dif f ic ult t o ident if y . Alt hough c audat e lobe hy pert rophy , c ompression and dist ort ion of t he hepat ic v eins, and het erogeneous hepat ic parenc hy mal enhanc ement c an be seen in pat ient s w it h end- st age c irrhosis, pat ient s w it h Budd- Chiari sy ndrome do not hav e a nodular liv er c ont our. Alt hough t he pat c hy hepat ic parenc hy mal enhanc ement pat t ern c harac t erist ic of t he ac ut e and subac ut e f orms of t he disease is usually present , some pat ient s w it h c hronic Budd- Chiari sy ndrome may hav e homogeneous hepat ic enhanc ement (498).

F igure 12- 106 Int rahepat ic port al v ein t hrombosis w it h t ransient hepat ic int ensit y dif f erenc e (T HID). Art erial phase gadolinium- enhanc ed T 1- w eight ed MR image (A) show s dif f usely inc reased signal int ensit y w it hin t he post erior segment of t he right hepat ic lobe due t o segment al port al v ein t hrombosis. Delay ed post c ont rast image (B) show s equilibrat ion of t he hepat ic parenc hy mal signal int ensit y . T hrombus c an be seen w it hin peripheral branc hes of t he port al v ein (ar r ow heads).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1928

12 - Liver

F igure 12- 107 Budd- Chiari sy ndrome. Cont rast - enhanc ed CT image show s pat c hy enhanc ement of t he liv er parenc hy ma w it h marked c ompression of t he int rahepat ic inf erior v ena c av a (ar r ow ). T he f ree int raperit oneal gas (ar r ow head) w as due t o a rupt ured duodenal ulc er.

MRI, like CT , demonst rat es t he c harac t erist ic morphologic f eat ures in pat ient s w it h Budd- Chiari sy ndrome: hepat omegaly , reduc t ion in c aliber or lac k of v isualizat ion of t he hepat ic v eins, marked narrow ing of t he int rahepat ic inf erior v ena c av a, c audat e lobe hy pert rophy , and asc it es (F ig. 12- 108) (187,759,771). T he hepat ic parenc hy mal signal int ensit y is usually het erogeneous. During t he ac ut e st age of t he disease, T 1- w eight ed imaging may show dec reased signal int ensit y in t he periphery of t he liv er, w it h more normal signal int ensit y in t he c audat e lobe. P.907 On T 2- w eight ed images t he periphery of t he liv er may be het erogeneously inc reased in signal int ensit y , w it h homogeneous normal int ensit y in t he c audat e lobe (15,592). Gadolinium- enhanc ed imaging demonst rat es het erogeneous hepat ic parenc hy mal enhanc ement , w it h early enhanc ement of t he c audat e lobe and c ent ral liv er parenc hy ma (see F ig. 12- 108) (187,592). T his enhanc ement pat t ern may persist on delay ed images or show rev ersal w it h lat e hy perenhanc ement of t he liv er periphery relat iv e t o t he c ent ral region (see F ig. 12- 108). T hrombi w it hin hepat ic v eins (see F ig. 12- 108) c an be ident if ied in most pat ient s, and dilat ed azy gous and hemizy gous v eins are ident if ied in approximat ely one t hird of pat ient s (759). Ot her c ommon port osy st emic c ollat eral rout es in Budd- Chiari sy ndrome inc lude t he asc ending lumbar v eins and v ert ebral v enous plexus (186). MRI may also demonst rat e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1929

12 - Liver int rahepat ic c ollat eral v essels, w hic h t y pic ally hav e t ort uous or c urv ilinear c onf igurat ion (186). In pat ient s w it h c hronic Budd- Chiari sy ndrome, t he regional dif f erenc es in signal int ensit y are muc h less pronounc ed, and c ont rast - enhanc ed imaging usually show s dif f use het erogeneous hepat ic

parenc hy mal enhanc ement on early and delay ed- phase images (187,592). Less c ommonly , t he hepat ic parenc hy ma may enhanc e homogeneously (187).

F igure 12- 108 Budd- Chiari sy ndrome. Art erial phase gadolinium- enhanc ed T 1w eight ed MR image (A) show s pref erent ial enhanc ement of t he c ent ral port ions of t he liv er surrounding t he unenhanc ed hepat ic v eins (ar r ow s). Not e t he perihepat ic asc it es. Delay ed post c ont rast image (B) demonst rat es rev ersal of t he earlier enhanc ement pat t ern, w it h more enhanc ement peripherally t han c ent rally . T he t hrombus- c ont aining hepat ic v eins remain unenhanc ed.

Some pat ient s w it h Budd- Chiari sy ndrome dev elop large benign regenerat iv e nodules, w hic h are usually mult iple and less t han 4 c m in diamet er (68,836). On unenhanc ed CT t hey are eit her isoat t enuat ing or hy perat t enuat ing (68,836). On unenhanc ed T 1- w eight ed MR images t he nodules appear hy point ense or hy perint ense, and on T 2- w eight ed images t heir signal int ensit y is v ariable, w it h many lesions being isoint ense (68,99,755,836). A small perc ent age of lesions may hav e a c ent ral sc ar t hat is hy perint ense on T 2w eight ed images and show s delay ed enhanc ement (479). Post c ont rast art erial phase CT and MR images demonst rat e hy perv asc ular lesions t hat enhanc e homogeneously (68,836). In some c ases, a perinodular ring may be ident if ied on bolus- enhanc ed CT or MR images, w hic h is due t o at rophic t issue in t he periphery of t he lesion or t he surrounding liv er w it h areas of sinusoidal dilat ion and c ongest ion (68). Hepat oc ellular c arc inoma has been report ed as a rare

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1930

12 - Liver c omplic at ion in pat ient s w it h Budd- Chiari sy ndrome (796,836). In a c linic al st udy of 157 pat ient s w it h Budd- Chiari sy ndrome, hepat oc ellular c arc inoma dev eloped in 6.4% of pat ient s during a 15- y ear f ollow - up period (607). How ev er, it has been suggest ed t hat t he dev elopment of hepat oc ellular c arc inoma in at least some of t hese pat ient s is relat ed t o c oexist ing v iral inf ec t ion (68).

Hepatic Veno-Occlusive Disease Veno- oc c lusiv e disease of t he liv er is an unc ommon disorder of hepat ic v enous out f low obst ruc t ion t hat oc c urs at t he lev el of t he small post sinusoidal v enules (554). It oc c urs in pat ient s rec eiv ing c hemot herapy , radiat ion, or immunosuppressiv e t herapy , but it also has been assoc iat ed w it h c onsumpt ion of herbal t eas (554). It af f ec t s 5% of pat ient s w ho undergo hemat opoiet ic st em c ell t ransplant at ion and usually dev elops w it hin t he f irst 3 w eeks of marrow inf usion (95). T he c linic al manif est at ions inc lude hepat omegaly , right upper- quadrant pain, asc it es, and jaundic e (824). T he MR imaging f indings hav e been report ed in sev eral pat ient s (554,824). Unenhanc ed imaging demonst rat es het erogeneous hepat ic signal int ensit y t hat is predominant ly hy point ense on T 1- w eight ed images and hy perint ense on T 2- w eight ed images (554). Af t er gadolinium administ rat ion, P.908 t he liv er enhanc es het erogeneously and t he main hepat ic v eins and inf erior v ena c av a show enhanc ement , exc luding Budd- Chiari sy ndrome (554,824). In t he proper c linic al set t ing, t he MRI f indings c an suggest t he diagnosis of hepat ic v eno- oc c lusiv e disease, but biopsy is generally required f or def init iv e diagnosis (804).

Passive Hepatic Congestion Passiv e hepat ic c ongest ion is a c omplic at ion of c ongest iv e heart f ailure or c onst ric t iv e peric ardit is. Elev at ed c ent ral v enous pressure leads t o dec reased hepat ic blood f low , elev at ed hepat ic v enous pressure, and art erial hy poxemia (171). T he c hronic hepat ic v enous hy pert ension result s in sinusoidal c ongest ion, dilat ion, and perisinusoidal edema (515). Pat ient s w it h hepat ic c ongest ion may hav e hepat omegaly , liv er t enderness, or elev at ed liv er f unc t ion t est s. If unc orrec t ed, t he abnormalit y may progress t o c ardiac c irrhosis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1931

12 - Liver T he major CT f eat ures of passiv e hepat ic c ongest ion are a dif f usely mot t led hepat ic parenc hy mal enhanc ement pat t ern (F ig. 12- 109) and ref lux of

c ont rast - enhanc ed blood f rom t he right at rium int o t he inf erior v ena c av a and hepat ic v eins (284,515,556). T he v ena c av a and hepat ic v eins are of t en dilat ed. Anc illary f indings inc lude c ardiomegaly , pleural ef f usions, asc it es, and int rahepat ic periv asc ular luc enc y (400). T he ret ic ulat ed- mosaic hepat ic parenc hy mal enhanc ement pat t ern in pat ient s w it h passiv e hepat ic c ongest ion is similar t o t hat seen in pat ient s w it h Budd- Chiari sy ndrome. T he prominenc e of t he hepat ic v eins and inf erior v ena c av a helps dist inguish passiv e hepat ic c ongest ion f rom Budd- Chiari sy ndrome. Pat ient s w it h t he lat t er disorder hav e a markedly narrow ed or oc c luded int rahepat ic v ena c av a and poorly v isualized or t hrombosed hepat ic v eins.

F igure 12- 109 Passiv e hepat ic v enous c ongest ion. Cont rast - enhanc ed CT image (A) show s enlargement of t he liv er and pat c hy hepat ic parenc hy mal enhanc ement . A more c ephalad image (B) show s marked enlargement of t he right at rium sec ondary t o t ric uspid regurgit at ion.

Hepatic Infarction Bec ause t he liv er has a dual blood supply , hepat ic inf arc t ion is unc ommon. How ev er, rec ent inc reases in t he use of liv er t ransplant at ion and laparosc opic c holec y st ec t omy (w it h t heir assoc iat ed v asc ular c omplic at ions) hav e led t o an inc rease in t he inc idenc e of liv er inf arc t ion (282,661). Alt hough t hese surgic al proc edures are now t he most c ommon c auses, liv er inf arc t ion rarely c an result f rom hepat ic art erial oc c lusion due t o at herosc lerosis, shoc k, sepsis, embolism, v asc ulit is, preec lampsia, t rauma, radiologic v asc ular int erv ent ional

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1932

12 - Liver proc edures, oral c ont rac ept iv e use, and disorders of hy perc oagulabilit y , suc h as ant iphospholipid sy ndrome (236,269,750,912). Hepat ic inf arc t s hav e v aried appearanc es at CT (F igs. 12- 110, 12- 111, 12112). T he t hree major c onf igurat ions t hat hav e been desc ribed are w edgeshaped, rounded, and irregularly shaped lesions paralleling bile duc t s (4,282,450,529,636,750). T he w edge- shaped lesions are usually peripheral, w hereas t he rounded lesions may be eit her peripheral or c ent ral. T he irregularly shaped lesion paralleling t he bile duc t s t end t o oc c ur in liv er

t ransplant pat ient s (see F ig. 12- 112) (282). Wit h t ime, areas of inf arc t ion may c hange in shape and may dev elop a more dist inc t margin (282,450). Subsequent nec rosis may result in c ent ral gas c ollec t ions (see F ig. 12- 112) (450). Chronic c hanges inc lude at rophy of t he inv olv ed segment and f ormat ion of c y st ic bile c ollec t ions sec ondary t o bile duc t nec rosis (163). P.909 At MRI, ac ut e hepat ic inf arc t s are hy point ense on T 1- w eight ed images and hy perint ense on T 2- w eight ed images ow ing t o edema. Gadolinium- enhanc ed imaging demonst rat es lac k of enhanc ement of t he inv olv ed areas.

F igure 12- 110 Hepat ic inf arc t ion. Cont rast - enhanc ed CT image show s a large peripheral hepat ic region of low at t enuat ion in a post operat iv e pat ient .

Peliosis Hepatis Peliosis hepat is is a rare disorder c harac t erized by irregular, blood- f illed spac es in t he liv er and c y st ic hepat ic sinusoidal dilat ion (565). It c an be seen

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1933

12 - Liver in pat ient s w it h c hronic w ast ing due t o t uberc ulosis or c anc er and is

assoc iat ed w it h administ rat ion of a v ariet y of drugs inc luding anabolic st eroids and oral c ont rac ept iv es (666,748). Peliosis hepat is also has been assoc iat ed w it h AIDS (666) and bac illary angiomat osis (881). T he disorder c an unc ommonly result in hepat ic f ailure, hemorrhagic nec rosis, or spont aneous hepat ic rupt ure (748,833). T he imaging appearanc e of peliosis hepat is is v ery v ariable and depends on lesion size, t he ext ent of c ommunic at ion w it h sinusoids, t he presenc e of hepat ic st eat osis, and t he presenc e of c omplic at ions suc h as t hrombosis or hemorrhage w it hin a lesion (391). Report ed appearanc es at CT inc lude mult iple rounded hy poat t enuat ing lesions dist ribut ed t hroughout t he liv er, w it h delay ed enhanc ement (666,881) (F ig. 12- 113), one or more large areas of het erogeneous hy poat t enuat ion w it h mild peripheral enhanc ement (775) (F ig. 12- 114), and small round lesions w it h early and prolonged enhanc ement (391). If t he liv er is f at t y , t he lesions may appear hy perat t enuat ing on unenhanc ed images. Wit h hemorrhagic nec rosis, unenhanc ed CT may show large areas of low at t enuat ion c ont aining smaller high- at t enuat ion f oc i (833). One report desc ribed t he mult iphasic helic al CT enhanc ement pat t ern of a solit ary large lesion, w hic h c onsist ed of dense globular c ent ral enhanc ement during t he art erial phase and progressiv e c ent rif ugal enhanc ement , w it h dif f use ac c umulat ion of c ont rast mat erial on t he delay ed phase (248), f eat ures t hat c ould be mist aken f or an at y pic al hemangioma or ot her v asc ular neoplasm. At MRI t he lesions are hy perint ense on T 2- w eight ed images and v ariable in signal int ensit y on T 1- w eight ed and prot on P.910 densit y - w eight ed images, likely ref lec t ing v arious st ages of subac ut e hemorrhage (516,775,892). One report desc ribed a branc hing pat t ern of enhanc ement on delay ed images af t er administ rat ion of Gd- BOPT A (203). A rare present at ion of peliosis hepat is is t hat of one or more large disc ret e masses. In t w o suc h pat ient s t he masses c ont ained innumerable small “ c y st ic ” or “ slit - like” v asc ular spac es, and delay ed enhanc ement of t he masses w as demonst rat ed af t er Gd- BOPT A administ rat ion, indic at ing t he presenc e of hepat oc y t es (832).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1934

12 - Liver

F igure 12- 111 Hepat ic inf arc t ion. Cont rast - enhanc ed CT image show s a large peripheral region of low at t enuat ion in a post part um pat ient w it h preec lampsia c omplic at ed by HELLP (hemorrhage, elev at ed liv er f unc t ion t est s, and low plat elet s) sy ndrome.

F igure 12- 112 Post t ransplant hepat ic inf arc t ion and nec rosis c aused by hepat ic art ery oc c lusion. Cont rast - enhanc ed CT image show s a large geographic low at t enuat ion, gas- c ont aining area in t he liv er.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1935

12 - Liver

F igure 12- 113 Peliosis hepat is. Mult iple rounded hy poat t enuat ing lesions are dist ribut ed t hroughout t he liv er in a pat ient w ho had been t reat ed w it h st eroids f or F anc oni anemia. Court esy of Pat ric k O. Gordon, MD.

F igure 12- 114 Peliosis hepat is. Cont rast - enhanc ed CT image show s a large hy poat t enuat ing and mildly het erogeneous region (ar r ow heads) inv olv ing t he lef t hepat ic lobe. Court esy of Andrew F isher, MD.

LIVER TRANSPLANTATION Pretransplant Evaluation

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1936

12 - Liver Liv er t ransplant at ion is a suc c essf ul t herapeut ic opt ion f or pat ient s w it h liv er f ailure. One- y ear surv iv al of liv er rec ipient s is now great er t han 80% (624).

CT and MRI are usef ul f or ev aluat ing pat ient s prior t o liv er t ransplant at ion and f or det ec t ing post operat iv e c omplic at ions. T he pre- operat iv e ev aluat ion of t he liv er t ransplant c andidat e (rec ipient ) is f oc used on assessment of hepat ic v asc ular anat omy and pat enc y , det ec t ion of hepat ic neoplasms, and c alc ulat ion of liv er v olume. In addit ion, t he presenc e of a splenic art ery aneury sm should be not ed bec ause splenic art ery aneury sms c an rupt ure af t er liv er t ranplant at ion, and t he posit ion of a t ransjugular int rahepat ic port osy st emic shunt , if present , should be det ermined (624). T he goal is t o prov ide t he surgeon w it h t he inf ormat ion nec essary t o perf orm t he surgic al proc edure and t o exc lude pat ient s f or w hom liv er t ransplant at ion eit her is not f easible or w ould be of no benef it (670). CT and MR ev aluat ion of t he liv ing right hepat ic lobe donor f oc uses on assessment of t he hepat ic parenc hy ma f or t he presenc e of st eat osis and inc ident al neoplasms, c alc ulat ion of t he right and lef t lobe v olumes t o ensure adequat e liv er v olume f or bot h t he rec ipient and donor, and assessment of t he hepat ic art erial, port al v enous, hepat ic v enous, and biliary anat omy t o ident if y v ariant s and anomalies t hat c an inc rease t he c omplexit y of t he surgic al proc edure. Bot h CT and MRI c an serv e as c ompreshensiv e noninv asiv e met hods f or pret ransplant rec ipient ev aluat ion. How ev er, dy namic c ont rast - enhanc ed MRI is slight ly more sensit iv e t han mult iphase helic al CT in det ec t ing hepat oc ellular c arc inomas (606,888). F or liv ing donor ev aluat ion, bot h CT and MRI are c apable of assessing v asc ular anat omy , P.911 liv er v olume, and hepat ic parenc hy ma (223,353,354,432,585,875). MRI, how ev er, is c apable of assessing t he biliary sy st em w it h MR c holangiography (223,432), w hereas t he normal biliary sy st em is not w ell- depic t ed at CT . T he ac c urac y of c onv ent ional T 2- w eight ed MR c holangiography in depic t ing normal biliary anat omy and anat omic v ariant s, how ev er, is only approximat ely 85% (432,466). Mn- DPDP- enhanc ed MR c holangiography depic t s t he int rahepat ic biliary sy st em more ac c urat ely t han does c onv ent ional T 2- w eight ed MR c holangiography , espec ially f or demonst rat ing right duc t v ariant s (361,433). Preliminary st udies of liv ing liv er donor ev aluat ion w it h CT c holangiography af t er administ rat ion of a c holangiographic c ont rast agent hav e show n promising result s (716,847,891). T hus, pot ent ially eit her CT or MRI c ould serv e as an all- in- one noninv asiv e met hod f or pre- operat iv e ev aluat ion of liv ing liv er donors.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1937

12 - Liver Posttransplant Complications

Despit e adv anc es in surgic al t ec hnique, pat ient selec t ion, organ preserv at ion, and immunosuppression, post t ransplant c omplic at ions c ont inue t o t hreat en surv iv al of t he t ransplant ed liv er and t he pat ient . Early diagnosis and t reat ment of post t ransplant c omplic at ions is t heref ore c rit ic al. Ult rasound is t he init ial imaging t est f or t he det ec t ion of c omplic at ions in t he early post t ransplant period bec ause it c an be perf ormed at t he bedside and is c apable of demonst rat ing t he hepat ic parenc hy a, v asc ulat ure, and bile duc t s (661). How ev er, CT and MRI serv e as exc ellent c omplement ary noninv asiv e imaging t est s w hen ult rasound result s are inc onc lusiv e (144,172,446,622,661). Hepat ic art ery t hrombosis is t he most c ommon and most sev ere v asc ular c omplic at ion af t er ort hot opic liv er t ransplant at ion, oc c uring in 4% t o 12% of adult rec ipient s and up t o 42% of c hildren (422,443,809,879). Bec ause t he donor bile duc t is ent irely dependent on hepat ic art erial blood supply , oc c lusion of t he hepat ic art ery leads t o bile duc t isc hemia and nec rosis (583). T he c linic al present at ion of hepat ic art ery t hrombosis may t ake t he f orm of hepat ic inf arc t s, ac ut e f ulminant hepat ic nec rosis, sepsis, or delay ed bile leak (816). Hepat ic art ery st enosis has been report ed t o oc c ur in approximat ely 5% of t ransplant rec ipient s and usually oc c urs at t he anast omosis (661). Sequelae of hepat ic art ery st enosis may inc lude hepat ic inf arc t s, absc esses, and biliary st ric t ures (1). If lef t unt reat ed, hepat ic art ery st enosis may progress t o t hrombosis (1,591). Bot h CT and MR angiography hav e been show n t o be ac c urat e f or diagnosing hepat ic art ery t hrombosis and st enosis (70,238,364,622,766). In addit ion, CT and MRI may demonst rat e bilomas, hepat ic inf arc t s (see F ig. 12- 112), absc esses, and biliary st ric t ures t hat result f rom dec reased or absent hepat ic art ery f low . Hepat ic art ery pseudoaneury sm is an unc ommon but lif e- t hreat ening c omplic at ion t hat usually oc c urs at t he anast omot ic sit e (583) and is w ell demonst rat ed by bot h CT (70) and MRI as a f oc ally enhanc ed enlargement of t he art ery . Int rahepat ic pseudoaneury sms are generally t he result of perc ut aneous liv er biopsy or loc al inf ec t ion (661). Port al v ein t hrombosis and st enosis af t er ort hot opic liv er t ransplant at ion are c onsidered t o be relat iv ely unc ommon, but are report ed t o oc c ur in 2% t o 13% of pat ient s (66,90,442,782). Pat ient s usually present w it h port al hy pert ension, gast roesophageal v aric es, or massiv e asc it es (670). T he diagnosis of port al v ein st enosis or t hrombosis is usually made w it h c olor Doppler ult rasound, but

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1938

12 - Liver CT and MRI are also exc ellent at demonst rat ing t he port al v enous abnormalit ies (70,238,329,622,766). St enosis or t hrombosis of t he inf erior v ena c av a is rare but may oc c ur at eit her t he suprahepat ic or inf rahepat ic anast omosis (670). Biliary c omplic at ions af t er liv er t ransplant at ion oc c ur in 13% t o 25% of pat ient s and usually oc c ur w it hin t he f irst 3 mont hs af t er t ransplant at ion (441,448,787). T he most c ommon c omplic at ion is bile leak, w hic h usually oc c urs at t he T - t ube sit e (583). Small leaks may c lose spont aneously , but large leaks may result in a biloma or bilious ac it es. Most biliary st ric t ures oc c ur at t he anast omot ic sit e and are c aused by sc ar f ormat ion (583).

Nonanast omot ic st ric t ures and nonanast omot ic bile duc t leaks t hat are not at t he T - t ube sit e are usually c aused by bile duc t isc hemia due t o hepat ic art ery st enosis or t hrombosis (92,909). Biliary st ric t ures f rom bile duc t isc hemia may oc c ur any w here in t he liv er, but t hey of t en st art at t he hilum and progress peripherally t o inv olv e t he int rahepat ic duc t s (583). Alt hough CT and MRI are c apable of ident if y ing and loc alizing many post t ransplant biliary c omplic at ions, t hey c urrent ly c annot replac e direc t c holangiography f or diagnosis of post t ransplant biliary st ric t ures (913). Hepat ic inf arc t s are usually due t o isc hemia c aused by dec reased or absent hepat ic art ery f low , muc h less c ommonly t o impairment of port al v enous blood f low (661). T hey appear at CT as w edge- shaped, rounded, or irregularly shaped hy poat t enuat ing areas on pre- and post c ont rast images (282) (see F ig. 12- 112). T he irregularly shaped inf arc t s of t en parallel t he bile duc t s. At MRI t hey appear hy point ense on T 1- w eight ed images and hy perint ense on T 2w eight ed images and show no enhanc ement af t er gadolinium administ rat ion (329). Pat ient s w ho undergo ort hot opic liv er t ransplant at ion are at inc reased risk f or dev eloping malignanc y bec ause of t he immunosuppressiv e t herapy administ ered t o av oid graf t rejec t ion. Approximat ely 4% t o 5% of liv er t ransplant rec ipient s dev elop malignant t umors, t he majorit y of w hic h are non- Hodgkin ly mphomas and squamous c ell skin c anc ers (799). Post t ransplant ly mphoprolif erat iv e disorder is an Epst ein- Barr v irus- induc ed B c ell ly mphoprolif erat ion t hat ranges f rom premalignant hy perplasia t o f rank ly mphoma (640). It oc c urs more f requent ly in t ransplant rec ipient s w it h hepat it is C v irus (523). Int rahepat ic manif est at ions inc lude mult iple hy poat t enuat ing f oc al hepat ic lesions, dif f use hepat ic parenc hy mal inf ilt rat ion, and periport al sof t t issue inf ilt rat ion (640). Port a hepat is ly mphadenopat hy may also be present (285,544). Pat ient s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1939

12 - Liver P.912 w ho undergo liv er t ransplant at ion f or hepat oc ellular c arc inoma or liv er met ast ases are at risk f or t umor rec urrenc e. F or pat ient s w it h hepat oc ellular

c arc inoma, t he risk of rec urrenc e is relat ed t o t he st age of t he t umor prior t o t ransplant at ion (202). T he most c ommon sit es of rec urrenc e are t he lungs and t he liv er allograf t , f ollow ed by t he regional and dist ant ly mph nodes (202). A c ommon CT f inding af t er liv er t ransplant at ion is an irregular, hy poat t enuat ing, nonenhanc ing area at t he liv er margin (2,197). T his f inding represent s subc apsular hepat ic nec rosis, a minor c omplic at ion t hat has been show n t o hav e lit t le c linic al prognost ic signif ic anc e (197). Anot her f requent f inding on post t ransplant CT examinat ions t hat has no apparent c linic al signif ic anc e is a c ollar of low at t enuat ion surrounding c ent ral and peripheral branc hes of t he port al v ein. T his periport al luc enc y likely is relat ed t o impaired ly mphat ic drainage c aused by surgic al int errupt ion of periport al ly mphat ic v essels (360,489,779). At MRI t he periport al c ollar is low in signal int ensit y on T 1- w eight ed images and high in signal int ensit y on T 2- w eight ed images (419).

REFERENCES 1. Abbasoglu O, Lev y MF , Vodapally MS, et al. Hepat ic art ery st enosis af t er liv er t ransplant at ion—inc idenc e, present at ion, t reat ment , and long t erm out c ome. T r ansplant at ion. 1997;63:250–255. 2. Abec assis JP, Parient e D, Hazebrouc q V, et al. Subc apsular hepat ic nec rosis in liv er t ransplant at ion: CT appearanc e. AJR Am J Roent genol. 1991;156:981–983. 3. Adkins MC, Halv orsen RAJ, duCret RP. CT ev aluat ion of at y pic al hepat ic f at t y met amorphosis. J Com put Assist T om ogr . 1990;14: 1013–1015. 4. Adler DD, Glazer GM, Silv er T M. Comput ed t omography of liv er inf arc t ion. AJR Am J Roent genol. 1984;142:315. 5. Ahmadi T , It ai Y , T akahashi M, et al. Angiomy olipoma of t he liv er: signif ic anc e of CT and MR dy namic st udy . Abdom Im aging. 1998;23:520–526. 6. Ahn IO, de Lange EE. Early hy perenhanc ement of c onf luent hepat ic f ibrosis on dy namic MR imaging. AJR Am J Roent genol. 1998;171: 901–902. 7. Aihara T , F ujioka M, Y amamot o K. Inc reased CT densit y of t he liv er due t o c is- diaminedic hloro plat inum (II). Pediat r Radiol. 1987;17:75–76. 8. Akhan O, Ozmen MN, Dinc er A, et al. Liv er hy dat id disease: long- t erm result s of perc ut aneous t reat ment . Radiology . 1996;198: 259–264.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1940

12 - Liver 9. Alpern MB, Law son T L, F oley WD, et al. F oc al hepat ic masses and f at t y inf ilt rat ion det ec t ed by enhanc ed dy namic CT . Radiology . 1986;158:45–49. 10. Alpers DH, Sabesin M. F at t y liv er: bioc hemic al and c linic al aspec t s. In:

Shif f L SE, ed. Diseases of t he liv er . Philadelphia: JB Lippinc ot t Co, 1982:813. 11. Apic ella PL, Mirow it z SA, Weinreb JC. Ext ension of v essels t hrough hepat ic neoplasms: MR and CT f indings. Radiology . 1994;191: 135–136. 12. Arai K, Mat sui O, T akashima T , et al. F oc al spared areas in f at t y liv er c aused by regional dec reased port al f low . AJR Am J Roent genol. 1988;151:300–302. 13. Araki T , Hay akaw a K, Okada J, et al. Hepat ic sc hist osomiasis japonic a ident if ied by CT . Radiology . 1985;157:757–760. 14. Arit a T , Mat sunaga N, T akano K, et al. Hepat ic perf usion abnormalit ies in ac ut e panc reat it is: CT appearanc e and c linic al import anc e. Abdom Im aging. 1999;24:157–162. 15. Arit a T , Mat sunaga N, Kobay ashi H. Budd- Chiari sy ndrome: peripheral abnormal int ensit y of t he liv er on magnet ic resonanc e imaging. Clin Radiol. 2000;55:640–642. 16. Arriv e L, F lejou JF , Vilgrain V, et al. Hepat ic adenoma: MR f indings in 51 pat hologic ally prov ed lesions. Radiology . 1994;193:507–512. 17. Ashida C, F ishman EK, Zerhouni EA, et al. Comput ed t omography of hepat ic c av ernous hemangioma. J Com put Assist T om ogr . 1987;11:455–460. 18. Auh Y H, Rosen A, Rubenst ein WA, et al. CT of t he papillary proc ess of t he c audat e lobe of t he liv er. AJR Am J Roent genol. 1984;142:535–538. 19. Auh Y H, Rubenst ein WA, Zirinsky K, et al. Ac c essory f issures of t he liv er: CT and sonographic appearanc e. AJR Am J Roent genol. 1984;143:565–572. 20. Aw ay a H, Mit c hell DG, Kamishima T , et al. Cirrhosis: modif ied c audat e- right lobe rat io. Radiology . 2002;224:769–774. 21. Bae KT , Brink JA, Heiken JP. Def init ion of equilibrium point (Reply ). Radiology . 1996;200:288–289. 22. Bae KT , Heiken JP, Brink JA. Aort ic and hepat ic c ont rast medium enhanc ement at CT . Part II. Ef f ec t of reduc ed c ardiac out put in a porc ine model. Radiology . 1998;207:657–662. 23. Bae KT , Heiken JP, Brink JA. Aort ic and hepat ic c ont rast medium enhanc ement at CT . Part I. Predic t ion w it h a c omput er model. Radiology . 1998;207:647–655.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1941

12 - Liver 24. Bae KT , Heiken JP, Brink JA. Aort ic and hepat ic peak enhanc ement at CT : ef f ec t of c ont rast medium injec t ion rat e—pharmac okinet ic analy sis and experiment al porc ine model. Radiology . 1998;206: 455–464.

25. Bae KT . Peak c ont rast enhanc ement in CT and MR angiography : w hen does it oc c ur and w hy ? Pharmac okinet ic st udy in a porc ine model. Radiology . 2003;227:809–816. 26. Baert AL, F ev ery J, Marc hal G, et al. Early diagnosis of Budd- Chiari sy ndrome by c omput ed t omography and ult rasonography : report of f iv e c ases. Gast r oent er ology . 1983;84:587–595. 27. Bailes DR, Gilderdale DJ, By dder GM, et al. Respirat ory ordered phase enc oding (ROPE): a met hod f or reduc ing respirat ory mot ion art ef ac t s in MR imaging. J Com put Assist T om ogr . 1985;9: 835–838. 28. Baker ME, Silv erman PM. Nodular f oc al f at t y inf ilt rat ion of t he liv er: CT appearanc e. AJR Am J Roent genol. 1985;145:79–80. 29. Balc i NC, Semelka RC, Noone T C, et al. Py ogenic hepat ic absc esses: MRI f indings on T 1- and T 2- w eight ed and serial gadolinium- enhanc ed gradient ec ho images. J Magn Reson Im aging. 1999;9: 285–290. 30. Balc i NC, Sirv anc i M. MR Imaging of inf ec t iv e liv er lesions. Magn Reson Im aging Clin N Am . 2002;10:121–135. 31. Barnes PA, T homas JL, Bernardino ME. Pit f alls in t he diagnosis of hepat ic c y st s by c omput ed t omography . Radiology . 1981;141: 129–133. 32. Baron RL, Campbell WL, Dodd GD III. Peribiliary c y st s assoc iat ed w it h sev ere liv er disease: imaging- pat hologic c orrelat ion. AJR Am J Roent genol. 1994;162:631–636. 33. Baron RL, Oliv er JH III, Dodd GD III, et al. Hepat oc ellular c arc inoma: ev aluat ion w it h biphasic , c ont rast - enhanc ed, helic al CT . Radiology . 1996;199:505–511. 34. Baron RL, Gore RM. Dif f use liv er disease. In: Gore RM, Lev ine MS, eds. T est book of Gast r oint est inal Radiology . Philadelphia: WB Saunders, 2000:1590–1638. 35. Bart olozzi C, Lenc ioni R, Caramella D, et al. Hepat oc ellular c arc inoma: CT and MR f eat ures af t er t ransc at het er art erial embolizat ion and perc ut aneous et hanol injec t ion. Radiology . 1994;191:123–128. 36. Bart olozzi C, Lenc ioni R, Caramella D, et al. T reat ment of hepat oc ellular c arc inoma w it h perc ut aneous et hanol injec t ion: ev aluat ion w it h c ont rast enhanc ed MR imaging. AJR Am J Roent genol. 1994;162:827–831.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1942

12 - Liver 37. Bashist B, Hec ht HL, Harley WD. Comput ed t omographic demonst rat ion of

rapid c hanges in f at t y inf ilt rat ion of t he liv er. Radiology . 1982;142:691–692. 38. Ba- Ssalamah A, Heinz- Peer G, Sc hima W, et al. Det ec t ion of f oc al hepat ic lesions: c omparison of unenhanc ed and SHU 555 A- enhanc ed MR imaging v ersus biphasic helic al CT AP. J Magn Reson Im aging. 2000;11:665–672. 39. Beggs I. T he radiology of hy dat id disease. AJR Am J Roent genol. 1985;145:639–648. 40. Bellin MF , Zaim S, Aubert on E, et al. Liv er met ast ases: saf et y and ef f ic ac y of det ec t ion w it h superparamagnet ic iron oxide in MR imaging. Radiology . 1994;193:657–663. P.913 41. Belt on RL, VanZandt T F . Congenit al absenc e of t he lef t lobe of t he liv er: a radiologic diagnosis. Radiology . 1983;147:184. 42. Berger JF , Laissy J- P, Limot O, et al. Dif f erent iat ion bet w een mult iple liv er hemangiomas and liv er met ast ases of gast rinomas: v alue of enhanc ed MRI. J Com put Assist T om ogr . 1996;20:349–355. 43. Bergeron P, Oliv a VL, Lalonde L, et al. Liv er angiomy olipoma: c lassic and unusual present at ions. Abdom Im aging. 1994;19:543–545. 44. Berland LL, Lee JY . Comparison of c ont rast media injec t ion rat es and v olumes f or hepat ic dy namic inc rement ed c omput ed t omography . Inv est Radiology . 1988;23:918–922. 45. Berland LL, Lee JKT . Liv er and biliary t rac t . In: Lee JKT , Sagel SS, St anley RJ, eds. Com put ed body t om ogr aphy w it h MRI c or r elat ion, 2nd ed. New Y ork: Rav en Press, 1989:593–660. 46. Berlow ME, Spirt BA, Weil L. CT f ollow - up of hepat ic and splenic f ungal mic roabsc esses. J Com put Assist T om ogr . 1984;8:42–45. 47. Bernardino ME. Comput ed t omography of c alc if ied liv er met ast ases. J Com put Assist T om ogr . 1979;3:32–35. 48. Bernardino ME, Berkman WA, Plemmons M, et al. Perc ut aneous drainage of mult isept at ed hepat ic absc ess. J Com put Assist T om ogr . 1984;8:38–41. 49. Bernardino ME, Y oung SW, Lee JK, et al. Hepat ic MR imaging w it h MnDPDP: saf et y , image qualit y , and sensit iv it y . Radiology . 1992;183:53–58. 50. Bhart ia B, Ward J, Gut hrie JA, et al. Hepat oc ellular c arc inoma in c irrhot ic liv ers: double- c ont rast t hin- sec t ion MR imaging w it h pat hologic c orrelat ion of explant ed t issue. AJR Am J Roent genol. 2003;180:577–584. 51. Bianc hi L. Gly c ogen st orage disease I and hepat oc ellular t umours. Eur J Pediat r . 1993;152 Suppl 1:S63–S70.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1943

12 - Liver

52. Biondet t i PR, F iore D, Muzzio PC. Comput ed t omography of t he liv er in v on Gierke's disease. J Com put Assist T om ogr . 1980;4:685–686. 53. Birnbaum BA, Weinreb JC, Megibow AJ, et al. Def init iv e diagnosis of hepat ic hemangiomas: MR imaging v ersus T c - 99m- labeled red blood c ell SPECT . Radiology . 1990;176:95–101. 54. Bismut h H. Surgic al anat omy and anat omic al surgery of t he liv er. Wor ld J Sur g. 1982;6:3–9. 55. Blakeborough A, Ward J, Wilson D, et al. Hepat ic lesion det ec t ion at MR imaging: a c omparat iv e st udy w it h f our sequenc es. Radiology . 1997;203:759–765. 56. Bluemke DA, Soy er PA, Chan BW, et al. Spiral CT during art erial port ography : t ec hnique and applic at ions. Radiogr aphic s. 1995; 15:623–637. 57. Bonaldi VM, Bret PM, Reinhold C, et al. Helic al CT of t he liv er: v alue of an early hepat ic art erial phase. Radiology . 1995;197: 357–363. 58. Bonkov sky HL, Rubin RB, Cable EE, et al. Hepat ic iron c onc ent rat ion: noninv asiv e est imat ion by means of MR imaging t ec hniques. Radiology . 1999;212:227–234. 59. Bosc h F X, Ribes J, Diaz M, et al. Primary liv er c anc er: w orldw ide inc idenc e and t rends. Gast r oent er ology . 2004;127:S5–S16. 60. Bot hw ell T H, RW C. Hemoc hromat osis. In: Sc hif f L, Sc hif f ER, eds. Diseases of t he liv er . Philadelphia: JB Lippinc ot t Co, 1982:1003. 61. Boulahdour H, Cherqui D, Charlot t e F , et al. T he hot spot hepat obiliary sc an in f oc al nodular hy perplasia. J Nuc l Med. 1993;34: 2105–2110. 62. Boy d PR, Mark GJ. Mult iple hepat ic adenomas and a hepat oc ellular c arc inoma in a man on oral met hy l t est ost erone f or elev en y ears. Canc er . 1977;40:1765–1770. 63. Bradbear RA, Bain C, Siskind V, et al. Cohort st udy of int ernal malignanc y in genet ic hemoc hromat osis and ot her c hronic nonalc oholic liv er diseases. J Nat l Canc er Inst . 1985;75:81–84. 64. Braga L, Semelka RC, Pedro MS, et al. Post - t reat ment malignant liv er lesions. MR imaging. Magn Reson Im aging Clin N Am . 2002; 10:53–73. 65. Branc at elli G, F ederle MP, Blac har A, et al. Hemangioma in t he c irrhot ic liv er: diagnosis and nat ural hist ory . Radiology . 2001;219: 69–74. 66. Branc at elli G, F ederle MP, Pealer K, et al. Port al v enous t hrombosis or sc lerosis in liv er t ransplant at ion c andidat es: preoperat iv e CT f indings and c orrelat ion w it h surgic al proc edure. Radiology . 2001;220:321–328.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1944

12 - Liver 67. Branc at elli G, F ederle MP, Grazioli L, et al. Hepat oc ellular c arc inoma in nonc irrhot ic liv er: CT , c linic al, and pat hologic f indings in 39 U.S. resident s. Radiology . 2002;222:89–94. 68. Branc at elli G, F ederle MP, Grazioli L, et al. Large regenerat iv e nodules in Budd- Chiari sy ndrome and ot her v asc ular disorders of t he liv er: CT and MR imaging f indings w it h c linic opat hologic c orrelat ion. AJR Am J Roent genol. 2002;178:877–883. 69. Branc at elli G, F ederle MP, Kat y al S, et al. Hemody namic c harac t erizat ion of f oc al nodular hy perplasia using t hree- dimensional v olume- rendered mult idet ec t or CT angiography . AJR Am J Roent genol. 2002;179:81–85. 70. Branc at elli G, Kat y al S, F ederle MP, et al. T hree- dimensional mult islic e helic al c omput ed t omography w it h t he v olume rendering t ec hnique in t he det ec t ion of v asc ular c omplic at ions af t er liv er t ransplant at ion. T r ansplant at ion. 2002;73:237–242. 71. Branc at elli G, Baron RL, Pet erson MS, et al. Helic al CT sc reening f or hepat oc ellular c arc inoma in pat ient s w it h c irrhosis: f requenc y and c auses of f alse- posit iv e int erpret at ion. AJR Am J Roent genol. 2003;180:1007–1014. 72. Branc at elli G, F ederle MP, Vilgrain V, et al. F ibropoly c y st ic liv er disease: CT and MR imaging f indings. Radiogr aphic s. 2005;25: 659–670. 73. Brandt DJ, Johnson CD, St ephens DH, et al. Imaging of f ibrolamellar hepat oc ellular c arc inoma. AJR Am J Roent genol. 1988;151: 295–299. 74. Branhart JL, Kuhnert N, Bakan DA, et al. Biodist ribut ion of GdC13 and GdDT PA and t heir inf luenc e on prot on magnet ic relaxat ion in rat t issues. Magn Reson Im aging. 1987;5:221. 75. Brasc h RC, Wesbey GE, Gooding CA, et al. Magnet ic resonanc e imaging of t ransf usional hemosiderosis c omplic at ing t halassemia major. Radiology . 1984;150:767.

76. Braw er MK, Aust in GE, Lew in KJ. F oc al f at t y c hange of t he liv er, a hit hert o poorly rec ognized ent it y . Gast r oent er ology . 1980;78: 247–252. 77. Bressler EL, Alpern MB, Glazer GM, et al. Hy perv asc ular hepat ic met ast ases: CT ev aluat ion. Radiology . 1987;162:49–51. 78. Bret PM, F ond A, Bret agnolle M, et al. Perc ut aneous aspirat ion and drainage of hy dat id c y st s in t he liv er. Radiology . 1988;168: 617–620. 79. Brit t AR, F ranc is IR, Glazer GM, et al. Sarc oidosis: abdominal manif est at ions at CT . Radiology . 1991;178:91–94. 80. Brow n JJ, Nay lor MJ, Y agan N. Imaging of hepat ic c irrhosis. Radiology . 1997;202:1–16.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1945

12 - Liver

81. Buet ow PC, Buc k JL, Ros PR, et al. Malignant v asc ular t umors of t he liv er: radiologic - pat hologic c orrelat ion. Radiogr aphic s. 1994;14: 153–166. 82. Buet ow PC, Buc k JL, Pant ongrag- Brow n L, et al. Biliary c y st adenoma and c y st adenoc arc inoma: c linic al- imaging- pat hologic c orrelat ions w it h emphasis on t he import anc e of ov arian st roma. Radiology . 1995;196:805–810. 83. Buet ow PC, Pant ongrag- Brow n L, Buc k JL, et al. F oc al nodular hy perplasia of t he liv er: radiologic - pat hologic c orrelat ion. Radiogr aphic s. 1996;16:369–388. 84. Buet ow PC, Buc k JL, Pant ongrag- Brow n L, et al. Undif f erent iat ed (embry onal) sarc oma of t he liv er: pat hologic basis of imaging f indings in 28 c ases. Radiology . 1997;203:779–783. 85. Burgener F A, Hamlin DJ. Cont rast enhanc ement in abdominal CT : bolus v s. inf usion. AJR Am J Roent genol. 1981;137:351–358. 86. Burgener F A, Hamlin DJ. Cont rast enhanc ement of f oc al hepat ic lesions in CT : ef f ec t of size and hist ology . AJR Am J Roent genol. 1983;140:297–301. 87. Burkart DJ, Johnson CD, Ehman RL, et al. Ev aluat ion of port al v enous hy pert ension w it h c ine phase- c ont rast MR f low measurement s: high assoc iat ion of hy perdy namic port al f low w it h v aric eal hemorrhage. Radiology . 1993;188:643–648. 88. Burkart DJ, Johnson CD, Mort on MJ, et al. Phase- c ont rast c ine MR angiography in c hronic liv er disease. Radiology . 1993;187: 407–412. 89. Burrel M, Llov et JM, Ay uso C, et al. MRI angiography is superior t o helic al CT f or det ec t ion of HCC prior t o liv er t ransplant at ion: an explant c orrelat ion. Hepat ology . 2003;38:1034–1042. 90. Busut t il RW, Shaked A, Millis JM, et al. One t housand liv er t ransplant s. T he lessons learned. Ann Sur g. 1994;219:490–497; disc ussion 498–499. 91. By dder GM, Chapman RW, Harry D, et al. Comput ed t omography at t enuat ion v alues in f at t y liv er. J Com put Assist T om ogr . 1981; 5:33–35. P.914 92. Campbell WL, Sheng R, Zajko AB, et alJ. Int rahepat ic biliary st ric t ures af t er liv er t ransplant at ion. Radiology . 1994;191:735–740. 93. Carlson SK, Johnson CD, Bender CE, et al. CT of f oc al nodular hy perplasia of t he liv er. AJR Am J Roent genol. 2000;174:705–712. 94. Carmody E, Y eung E, Mc Loughlin M. Angiomy olipomas of t he liv er in t uberous sc lerosis. Abdom Im aging. 1994;19:537–539. 95. Carreras E, Bert z H, Arc ese W, et al. Inc idenc e and out c ome of hepat ic v eno- oc c lusiv e disease af t er blood or marrow t ransplant at ion: a prospec t iv e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1946

12 - Liver c ohort st udy of t he European Group f or Blood and Marrow T ransplant at ion. European Group f or Blood and Marrow T ransplant at ion Chronic Leukemia Working Part y . Blood. 1998;92:3599–3604. 96. Caseiro- Alv es F , Zins M, Mahf ouz AE, et al. Calc if ic at ion in f oc al nodular

hy perplasia: a new problem f or dif f erent iat ion f rom f ibrolamellar hepat oc ellular c arc inoma. Radiology . 1996;198: 889–892. 97. Cat alano O, Lobianc o R, Esposit o M, et al. Hepat oc ellular c arc inoma rec urrenc e af t er perc ut aneous ablat ion t herapy : helic al CT pat t erns. Abdom Im aging. 2001;26:375–383. 98. Cat asc a JV, Mirow it z SA. T 2- w eight ed MR imaging of t he abdomen: f ast spin- ec ho v s c onv ent ional spin- ec ho sequenc es. AJR Am J Roent genol. 1994;162:61–67. 99. Cazals- Hat em D, Vilgrain V, Genin P, et al. Art erial and port al c irc ulat ion and parenc hy mal c hanges in Budd- Chiari sy ndrome: a st udy in 17 explant ed liv ers. Hepat ology . 2003;37:510–519. 100. Cesmeli E, Vogelaers D, Voet D, et al. Ult rasound and CT c hanges of liv er parenc hy ma in ac ut e sc hist osomiasis. Br J Radiol. 1997;70: 758–760. 101. Cha I, Cart w right D, Guis M, et al. Angiomy olipoma of t he liv er in f ineneedle aspirat ion biopsies: it s dist inc t ion f rom hepat oc ellular c arc inoma. Canc er . 1999;87:25–30. 102. Chambers T P, Baron RL, Lush RM. Hepat ic CT enhanc ement . Part II. Alt erat ions in c ont rast mat erial v olume and rat e of injec t ion w it hin t he same pat ient s. Radiology . 1994;193:518–522. 103. Chambers T P, Baron RL, Lush RM. Hepat ic CT enhanc ement . Part I. Alt erat ions in t he v olume of c ont rast mat erial w it hin t he same pat ient s. Radiology . 1994;193:513–517. 104. Champet ier J, Y v er R, Let oublon C, et al. A general rev iew of anomalies of hepat ic morphology and t heir c linic al implic at ions. Anat Clin. 1985;7:285–299. 105. Chang JC, Lee Y W, Kim HJ. Preoperat iv e diagnosis of angiomy olipoma of t he liv er. Abdom Im aging. 1994;19:546–548. 106. Chaoui A, Mergo PJ, Lauw ers GY . Unusual appearanc e of f oc al nodular hy perplasia w it h f at t y c hange. AJR Am J Roent genol. 1998;171:1433–1434. 107. Chapman RW, Williams G, By dder G, et al. Comput ed t omography f or det ermining liv er iron c ont ent in primary haemoc hromat osis. Br Med J. 1980;280:440–442.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1947

12 - Liver 108. Chen JH, Chai JW, Huang CL, et al. Proximal art erioport al shunt ing assoc iat ed w it h hepat oc ellular c arc inoma: f eat ures rev ealed by dy namic helic al CT . AJR Am J Roent genol. 1999;172: 403–407. 109. Chen WP, Chen JH, Hw ang JI, et al. Spec t rum of t ransient hepat ic at t enuat ion dif f erenc es in biphasic helic al CT . AJR Am J Roent genol. 1999;172:419–424. 110. Cheng HC, T sai SH, Chiang JH, et al. Hy alinized liv er hemangioma mimic king malignant t umor at MR imaging. AJR Am J Roent genol. 1995;165:1016–1017. 111. Chezmar JL, Nelson RC, Malko JA, et al. Hepat ic iron ov erload: diagnosis and quant if ic at ion by noninv asiv e imaging. Gast r oint est Radiol. 1990;15:27–31. 112. Chezmar JL, Bernardino ME, Kauf man SH, et al. Combined CT art erial port ography and CT hepat ic angiography f or ev aluat ion of t he hepat ic resec t ion c andidat e. Work in progress. Radiology . 1993;189:407–410. 113. Cho KC, Pat el Y D, Wac hsberg RH, et al. Varic es in port al hy pert ension: ev aluat ion w it h CT . Radiogr aphic s. 1995;15:609–622.

114. Choi BI, Han MC, Park JH, et al. Giant c av ernous hemangioma of t he liv er: CT and MR imaging in 10 c ases. AJR Am J Roent genol. 1989;152:1221–1226. 115. Choi BI, Lim JH, Han MC, et al. Biliary c y st adenoma and c y st adenoc arc inoma: CT and sonographic f indings. Radiology . 1989;171: 57–61. 116. Choi BI, Han MC, Kim CW. Small hepat oc ellular c arc inoma v ersus small c av ernous hemangioma: dif f erent iat ion w it h MR imaging at 2.0 T . Radiology . 1990;176:103–106. 117. Choi BI, Lee GK, Kim ST , et al. Mosaic pat t ern of enc apsulat ed hepat oc ellular c arc inoma: c orrelat ion of magnet ic resonanc e imaging and pat hology . Gast r oint est Radiol. 1990;15:238–240. 118. Choi BI, Kim HC, Han JK, et al. T herapeut ic ef f ec t of t ransc at het er oily c hemoembolizat ion t herapy f or enc apsulat ed nodular hepat oc ellular c arc inoma: CT and pat hologic f indings. Radiology . 1992; 182:709–713. 119. Choi BI, T akay asu K, Han MC. Small hepat oc ellular c arc inomas and assoc iat ed nodular lesions of t he liv er: pat hology , pat hogenesis, and imaging f indings. AJR Am J Roent genol. 1993;160:1177–1187. 120. Choi BI, Han JK, Shin Y M, et al. Peripheral c holangioc arc inoma: c omparison of MRI w it h CT . Abdom Im aging. 1995;20:357–360.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1948

12 - Liver 121. Choi BI, Lee HJ, Han JK, et al. Det ec t ion of hy perv asc ular nodular

hepat oc ellular c arc inomas: v alue of t riphasic helic al CT c ompared w it h iodizedoil CT . AJR Am J Roent genol. 1997;168: 219–224. 122. Choi BI, Han JK, Hong SH, et al. Dy splast ic nodules of t he liv er: imaging f indings. Abdom Im aging. 1999;24:250–257. 123. Choi CS, F reeny PC. T riphasic helic al CT of hepat ic f oc al nodular hy perplasia: inc idenc e of at y pic al f indings. AJR Am J Roent genol. 1998;170:391–395. 124. Choi D, Kim S, Lim J, et al. Preoperat iv e det ec t ion of hepat oc ellular c arc inoma: f erumoxides- enhanc ed MR imaging v ersus c ombined helic al CT during art erial port ography and CT hepat ic art eriography . AJR Am J Roent genol. 2001;176:475–482. 125. Choi H, Loy er EM, DuBrow RA, et al. Radio- f requenc y ablat ion of liv er t umors: assessment of t herapeut ic response and c omplic at ions. Radiogr aphic s. 2001;21 Spec No:S41–S54. 126. Choi SH, Lee JM, Lee KH, et al. Relat ionship bet w een v arious pat t erns of t ransient inc reased hepat ic at t enuat ion on CT and port al v ein t hrombosis relat ed t o ac ut e c holec y st it is. AJR Am J Roent genol. 2004;183:437–442. 127. Choliz JD, Olav erri F JL, Casa T F , et al. Comput ed t omography in hepat ic ec hinoc oc c osis. AJR Am J Roent genol. 1982;139: 699–702. 128. Chung KY , May o- Smit h WW, Saini S, et al. Hepat oc ellular adenoma: MR imaging f eat ures w it h pat hologic c orrelat ion. AJR Am J Roent genol. 1995;165:303–308. 129. Clark PR, St Pierre T G. Quant it at iv e mapping of t ransv erse relaxiv it y (1/T (2)) in hepat ic iron ov erload: a single spin- ec ho imaging met hodology . Magn Reson Im aging. 2000;18:431–438. 130. Claudon M, Bessieres M, Regent D, et al. Alv eolar ec hinoc oc c osis of t he liv er: MR f indings. J Com put Assist T om ogr . 1990;14: 608–614. 131. Claussen CD, Banzer D, Pf ret zsc hner C, et al. Bolus geomet ry and dy namic s af t er int rav enous c ont rast medium injec t ion. Radiology . 1984;153:365–368. 132. Clement O, Muhler A, Vexler VS, et al. Ev aluat ion of radiat ion- induc ed liv er injury w it h MR imaging: c omparison of hepat oc ellular and ret ic uloendot helial c ont rast agent s. Radiology . 1992;185: 163–168. 133. Coakley F V, O'Reilly EM, Sc hw art z LH, et al. Non- Hodgkin ly mphoma as a c ause of int rahepat ic periport al low at t enuat ion on CT . J Com put Assist T om ogr . 1997;21:726–728.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1949

12 - Liver

134. Cof f in CM, Dic he T , Mahf ouz A, et al. Benign and malignant hepat oc ellular t umors: ev aluat ion of t umoral enhanc ement af t er mangaf odipir t risodium injec t ion on MR imaging. Eur Radiol. 1999;9:444–449. 135. Coire CI, Qizilbash AH, Cast elli MF . Hepat ic adenomat a in t y pe Ia gly c ogen st orage disease. Ar c h Pat hol Lab Med. 1987;111: 166–169. 136. Cont reras P, Alt ieri E, Liberman C, et al. Adrenal rest t umor of t he liv er c ausing Cushing's sy ndrome: t reat ment w it h ket oc onazole prec eding an apparent surgic al c ure. J Clin Endoc r inol Met ab. 1985;60:21–28. 137. Corrigan K, Semelka RC. Dy namic c ont rast - enhanc ed MR imaging of f ibrolamellar hepat oc ellular c arc inoma. Abdom Im aging. 1995;20:122–125. 138. Couanet D, Shirkhoda A, Wallac e S. Comput ed t omography af t er part ial hepat ec t omy . J Com put Assist T om ogr . 1984;8:453–457. 139. Couinaud C. Le f oie: et udes anat om iques et c hir ur gic ales. Paris: Masson, 1957. P.915 140. Coulam CH, Chan F P, Li KC. Can a mult iphasic c ont rast - enhanc ed t hreedimensional f ast spoiled gradient - rec alled ec ho sequenc e be suf f ic ient f or liv er MR imaging? AJR Am J Roent genol. 2002;178: 335–341. 141. Craig J, Pet ers R, Edmonson H. T um or s of t he liv er and int r ahepat ic bile duc t s (sec ond ser ies). At las of t um or pat hology , v ol f asc ic le 26. Washingt on, DC: Armed F orc es Inst it ut e of Pat hology , 1989. 142. Czermak BV, Unsinn KM, Got w ald T , et al. Ec hinoc oc c us mult iloc ularis rev isit ed. AJR Am J Roent genol. 2001;176:1207–1212. 143. Czerniak A, Soreide O, Gibson RN, et al. Liv er at rophy c omplic at ing benign bile duc t st ric t ures. Surgic al and int erv ent ional radiologic approac hes. Am J Sur g. 1986;152:294–300. 144. Dalen K, Day DL, Asc her NL, et al. Imaging of v asc ular c omplic at ions af t er hepat ic t ransplant at ion. AJR Am J Roent genol. 1988;150: 1285–1290. 145. Danet IM, Semelka RC, Braga L. MR imaging of dif f use liv er disease. Radiol Clin Nor t h Am . 2003;41:67–87. 146. Danet IM, Semelka RC, Leonardou P, et al. Spec t rum of MRI appearanc es of unt reat ed met ast ases of t he liv er. AJR Am J Roent genol. 2003;181:809–817. 147. Dav olio Marani SA, Canossi GC, Nic oli F A, et al. Hy dat id disease: MR imaging st udy . Radiology . 1990;175:701–706.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1950

12 - Liver

148. Daw son J, T an K. Anat omy of t he liv er. In: Millw ard- Sadler GH, Wright R, Art hur MJP, eds. Wr ight 's liv er and biliar y disease, v ol 2, 3rd ed. Philadelphia: WB Saunders, 1992:3–11. 149. Daw son P, Blomley M. Def init ion of “ equilibrium point ” . Radiology . 1996;200:288–289. 150. De Bruec ker Y , Ballaux F , Allew aert S, et al. A solit ary hepat ic lesion: MRI- pat hologic al c orrelat ion of an hepat ic angiomy olipoma (2004:4b). Eur Radiol. 2004;14:1324–1326. 151. de Lange EE, Mugler JP III, Gay SB, et al. F oc al liv er disease: c omparison of breat h- hold T 1- w eight ed MP- GRE MR imaging and c ont rast - enhanc ed CT —lesion det ec t ion, loc alizat ion, and c harac t erizat ion. Radiology . 1996;200:465–473. 152. de Ledinghen V, Laharie D, Lec esne R, et al. Det ec t ion of nodules in liv er c irrhosis: spiral c omput ed t omography or magnet ic resonanc e imaging? A prospec t iv e st udy of 88 nodules in 34 pat ient s. Eur J Gast r oent er ol Hepat ol. 2002;14:159–165. 153. De Maria M, De Simone G, Lac oni A, et al. Gold st orage in t he liv er: appearanc e on CT sc ans. Radiology . 1986;159:355–356. 154. De Sant is M, Alborino S, T art oni PL, et al. Ef f ec t s of lipiodol ret ent ion on MRI signal int ensit y f rom hepat oc ellular c arc inoma and surrounding liv er t reat ed by c hemoembolizat ion. Eur Radiol. 1997;7:10–16. 155. Dean PB, Violant e MR, Mahoney JA. Hepat ic CT c ont rast enhanc ement : ef f ec t of dose, durat ion of inf usion, and t ime elapsed f ollow ing inf usion. Inv est Radiol. 1980;15:158–161. 156. Def landre MF , Vilgrain V, Zins M, et al. Nont umorous at t enuat ion c hanges on CT art erial port ography . J Com put Assist T om ogr . 1994;18:761–767. 157. DeGroot e J, Gedigk P, Popper H, et al. A c lassif ic at ion of c hronic hepat it is. Lanc et . 1994;1978:626–628. 158. Demaerel P, Marc hal G, Van St eenbergen W, et al. CT demonst rat ion of right hepat ic lobe at rophy . J Com put Assist T om ogr . 1989; 13:351–353. 159. Deny s A, Arriv e L, Serv ois V, et al. Hepat ic t umors: det ec t ion and c harac t erizat ion at 1- T MR imaging enhanc ed w it h AMI- 25. Radiology . 1994;193:665–669. 160. Dixon AK, Walshe JM. Comput ed t omography of t he liv er in Wilson disease. J Com put Assist T om ogr . 1984;8:46–49.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1951

12 - Liver 161. Do H, Lambiase RE, Dey oe L, et al. Perc ut aneous drainage of hepat ic absc esses: c omparison of result s in absc esses w it h and w it hout int rahepat ic biliary c ommunic at ion. AJR Am J Roent genol. 1991;157:1209–1212. 162. Dodds WJ, Eric kson SJ, T ay lor AJ, et al. Caudat e lobe of t he liv er: anat omy , embry ology , and pat hology . AJR Am J Roent genol. 1990; 154:87–93. 163. Doppman JL, Dunnic k NR, Girt on M, et al. Bile duc t c y st s sec ondary t o liv er inf arc t s: report of a c ase and experiment al produc t ion by small v essel hepat ic art ery oc c lusion. Radiology . 1979;130:1–5. 164. Doppman JL, Cornblat h M, Dw y er AJ, et al. Comput ed t omography of t he liv er and kidney s in gly c ogen st orage disease. J Com put Assist T om ogr . 1982;6:67–71. 165. Doppman JL, Dw y er A, Vermess M, et al. Segment al hy perluc ent def ec t s in t he liv er. J Com put Assist T om ogr . 1984;8:50–57.

166. Dorio PJ, Lee F T Jr, Henseler KP, et al. Using a saline c haser t o dec rease c ont rast media in abdominal CT . AJR Am J Roent genol. 2003;180:929–934. 167. Doy le F H, Pennoc k JM, Banks LM, et al. Nuc lear magnet ic resonanc e imaging of t he liv er: init ial experienc e. AJR Am J Roent genol. 1982;138:193–200. 168. Dromain C, de Baere T , Elias D, et al. Hepat ic t umors t reat ed w it h perc ut aneous radio- f requenc y ablat ion: CT and MR imaging f ollow - up. Radiology . 2002;223:255–262. 169. DuBrow RA, Dav id CL, Libshit z HI, et al. Det ec t ion of hepat ic met ast ases in breast c anc er: t he role of nonenhanc ed and enhanc ed CT sc anning. J Com put Assist T om ogr . 1990;14: 366–369. 170. Duc ommun JC, Goldberg HI, Korobkin M, et al. T he relat ion of liv er f at t o c omput ed t omography numbers: a preliminary experiment al st udy in rabbit s. Radiology . 1979;130:511–513. 171. Dunn GD, Hay es P, Breen KJ, et al. T he liv er in c ongest iv e heart f ailure: a rev iew . Am J Med Sc i. 1973;265:174–189. 172. Dupuy D, Cost ello P, Lew is D, et al. Abdominal CT f indings af t er liv er t ransplant at ion in 66 pat ient s. AJR Am J Roent genol. 1991;156: 1167–1170. 173. Dw y er A, Doppman JL, Adams AJ, et al. Inf luenc e of gly c ogen on liv er densit y : c omput ed t omography f rom a met abolic perspec t iv e. J Com put Assist T om ogr . 1983;7:70–73.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1952

12 - Liver 174. Earls JP, T heise ND, Weinreb JC, et al. Dy splast ic nodules and

hepat oc ellular c arc inoma: t hin- sec t ion MR imaging of explant ed c irrhot ic liv ers w it h pat hologic c orrelat ion. Radiology . 1996;201: 207–214. 175. Earls JP, Rof sky NM, DeCorat o DR, et al. Hepat ic art erial- phase dy namic gadolinium- enhanc ed MR imaging: opt imizat ion w it h a t est examinat ion and a pow er injec t or. Radiology . 1997;202: 268–273. 176. Earls JP, Rof sky NM, DeCorat o DR, et al. Ec ho- t rain ST IR MRI of t he liv er: c omparison of breat h- hold and non- breat h- hold imaging st rat egies. J Magn Reson Im aging. 1999;9:87–92. 177. Ebara M, Oht o M, Wat anabe Y , et al. Diagnosis of small hepat oc ellular c arc inoma: c orrelat ion of MR imaging and t umor hist ologic st udies. Radiology . 1986;159:371–377. 178. Ebara M, F ukuda H, Kojima Y , et al. Small hepat oc ellular c arc inoma: relat ionship of signal int ensit y t o hist opat hologic f indings and met al c ont ent of t he t umor and surrounding hepat ic parenc hy ma. Radiology . 1999;210:81–88. 179. Edelman RR, Hahn PF , Buxt on R, et al. Rapid MR imaging w it h suspended respirat ion: c linic al applic at ion in t he liv er. Radiology . 1986;161:125–131. 180. Edelman RR, Mat t le HP, Kleef ield J, et al. Quant if ic at ion of blood f low w it h dy namic MR imaging and presat urat ion bolus t rac king. Radiology . 1989;171:551–556. 181. Edmondson HA, Henderson B, Bent on B. Liv er- c ell adenomas assoc iat ed w it h use of oral c ont rac ept iv es. N Engl J Med. 1976; 294:470–472. 182. Edmondson HA, Rey nolds T B, Henderson B, et al. Regression of liv er c ell adenomas assoc iat ed w it h oral c ont rac ept iv es. Ann Int er n Med. 1977;86:180–182. 183. Elizondo G, Weissleder R, St ark DD, et al. Amebic liv er absc ess: diagnosis and t reat ment ev aluat ion w it h MR imaging. Radiology . 1987;165:795–800. 184. Elizondo G, F ret z CJ, St ark DD, et al. Prec linic al ev aluat ion of MnDPDP: new paramagnet ic hepat obiliary c ont rast agent f or MR imaging. Radiology . 1991;178:73–78. 185. El- Serag HB. Hepat oc ellular c arc inoma: rec ent t rends in t he Unit ed St at es. Gast r oent er ology . 2004;127:S27–S34. 186. Erden A, Erden I, Karay alc in S, et al. Budd- Chiari sy ndrome: ev aluat ion w it h mult iphase c ont rast - enhanc ed t hree- dimensional MR angiography . AJR Am J Roent genol. 2002;179:1287–1292.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1953

12 - Liver 187. Erden A, Erden I, Y urday din C, et al. Hepat ic out f low obst ruc t ion: enhanc ement pat t erns of t he liv er on MR angiography . Eur J Radiol. 2003;48:203–208. 188. Ernst O, Sergent G, Bonv arlet P, et al. Hepat ic iron ov erload: diagnosis and quant if ic at ion w it h MR imaging. AJR Am J Roent genol. 1997;168:1205–1208. P.916 189. Ev erson GT , T ay lor MR, Doc t or RB. Poly c y st ic disease of t he liv er. Hepat ology . 2004;40:774–782. 190. F an ZM, Y amashit a Y , Harada M, et al. Int rahepat ic c holangioc arc inoma: spin- ec ho and c ont rast - enhanc ed dy namic MR imaging. AJR Am J Roent genol. 1993;161:313–317. 191. F ashir BM, Gaw det S, Al Momen S, et al. Mesenc hy mal hamart oma in a 21- y ear- old man. Pediat r Radiol. 1998;28:514. 192. F at aar S, Bassiony H, Sat y anat h S, et al. CT of hepat ic sc hist osomiasis mansoni. AJR Am J Roent genol. 1985;145:63–66. 193. F at t ov ic h G, St rof f olini T , Zagni I, et al. Hepat oc ellular c arc inoma in

c irrhosis: inc idenc e and risk f ac t ors. Gast r oent er ology . 2004;127: S35–S50. 194. F ederle M, Chezmar J, Rubin DL, et al. Ef f ic ac y and saf et y of mangaf odipir t risodium (MnDPDP) injec t ion f or hepat ic MRI in adult s: result s of t he U.S. Mult ic ent er phase III c linic al t rials. Ef f ic ac y of early imaging. J Magn Reson Im aging. 2000;12: 689–701. 195. F ederle MP, F illy RA, Moss AA. Cy st ic hepat ic neoplasms: c omplement ary roles of CT and sonography . AJR Am J Roent genol. 1981;136:345–348. 196. F ederle MP, Jef f rey RB Jr, Minagi H. Case report . Calc if ied liv er met ast asis f rom renal c ell c arc inoma. J Com put Assist T om ogr . 1981;5:771–772. 197. F eld R, Wec hsler RJ, Dumsha JZ, et al. Signif ic anc e of t he c omput ed t omography f inding of subc apsular hepat ic nec rosis in liv er t ransplant at ion. Abdom Im aging. 1996;21:161–165. 198. F ellow s KE Jr, Vaw t er GF , T ef f t M. Hepat ic ef f ec t s f ollow ing abdominal irradiat ion in c hildren: det ec t ion by Au198 sc an and c onf irmat ion by hist ologic examinat ion. Am J Roent genol Radium T her Nuc l Med. 1968;103:422–431. 199. F ennessy F M, Mort ele KJ, Kluc kert T , et al. Hepat ic c apsular ret rac t ion in met ast at ic c arc inoma of t he breast oc c urring w it h inc rease or dec rease in size of subjac ent met ast asis. AJR Am J Roent genol. 2004;182:651–655.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1954

12 - Liver

200. F ernandez M. Hepat ic pseudolesion: appearanc e of f oc al low at t enuat ion in t he medial segment of t he lef t lobe at CT art erial port ography . Radiology . 1991;181:809–812. 201. F errell L, Wright T , Lake J, et al. Inc idenc e and diagnost ic f eat ures of mac roregenerat iv e nodules v s. small hepat oc ellular c arc inoma in c irrhot ic liv ers. Hepat ology . 1992;16:1372–1381. 202. F erris JV, Baron RL, Marsh JW Jr, et al. Rec urrent hepat oc ellular c arc inoma af t er liv er t ransplant at ion: spec t rum of CT f indings and rec urrenc e pat t erns. Radiology . 1996;198:233–238. 203. F errozzi F , T ognini G, Zuc c oli G, et al. Peliosis hepat is w it h pseudot umoral and hemorrhagic ev olut ion: CT and MR f indings. Abdom Im aging. 2001;26:197–199. 204. F erruc c i J, F reeny P, St ark DD, et al. Adv anc es in hepat obiliary radiology . Radiology . 1988;168:319–338. 205. F inc h SC, F inc h CA. Idiopat hic hemoc hromat osis, an iron st orage disease. A. Iron met abolism in hemoc hromat osis. Medic ine (Balt im or e). 1955;34:381–430. 206. F inn JP, Kane RA, Edelman RR, et al. Imaging of t he port al v enous sy st em in pat ient s w it h c irrhosis: MR angiography v s duplex Doppler sonography . AJR Am J Roent genol. 1993;161:989–994. 207. F lejou JF , Barge J, Menu Y , et al. Liv er adenomat osis. An ent it y dist inc t f rom liv er adenoma? Gast r oent er ology . 1985;89:1132–1138. 208. F lic kinger F W, Pf eif er EA. Hepat ic sarc oidosis: MR f indings. AJR Am J Roent genol. 1991;156:1324–1325. 209. F lournoy JG, Pot t er JL, Sulliv an BM, et al. CT appearanc e of mult if oc al hepat ic st eat osis. J Com put Assist T om ogr . 1984;8:1192–1194. 210. F oley WD. Dy namic hepat ic CT . Radiology . 1989;170:617–622. 211. F oley WD, Mallisee T A, Hohenw alt er MD, et al. Mult iphase hepat ic CT w it h a mult irow det ec t or CT sc anner. AJR Am J Roent genol. 2000;175:679–685. 212. F ost er JH, Berman MM. T he malignant t ransf ormat ion of liv er c ell adenomas. Ar c h Sur g. 1994;129:712–717. 213. F ranc is IR, Glazer GM, Amendola MA, et al. Hepat ic absc esses in t he immunoc ompromised pat ient : role of CT in det ec t ion, diagnosis, management , and f ollow - up. Gast r oint est Radiol. 1986;11: 257–262.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1955

12 - Liver 214. F ranc o LM, Krishnamurt hy V, Bali D, et al. Hepat oc ellular c arc inoma in gly c ogen st orage disease t y pe Ia: a c ase series. J Inher it Met ab Dis. 2005;28:153–162. 215. F rederic k MG, Paulson EK, Nelson RC. Helic al CT f or det ec t ing f oc al liv er lesions in pat ient s w it h breast c arc inoma: c omparison of nonc ont rast phase, hepat ic art erial phase, and port al v enous phase. J Com put Assist T om ogr . 1997;21:229–235. 216. F reeny PC, Marks WM. Comput ed t omographic art eriography of t he liv er. Radiology . 1983;148:193–197. 217. F reeny PC, Marks WM. Hepat ic hemangioma: dy namic bolus CT . AJR Am J Roent genol. 1986;147:711–719. 218. F reeny PC, Marks WM. Hepat ic perf usion abnormalit ies during CT angiography : det ec t ion and int erpret at ion. Radiology . 1986;159: 685–691. 219. F reeny PC, Baron RL, T eef ey SA. Hepat oc ellular c arc inoma: reduc ed f requenc y of t y pic al f indings w it h dy namic c ont rast - enhanc ed CT in a nonAsian populat ion. Radiology . 1992;182:143–148. 220. F riedman A, Johns T , Lev y D, et al. Cirrhosis, ot her dif f use disease, port al hy pert ension, and v asc ular disease. In: F riedman AC, ed. Radiology of t he liv er , biliar y t r ac t , panc r eas and spleen. Balt imore: Williams & Wilkins, 1987:69. 221. F riedman AC, Lic ht enst ein JE, Goodman Z, et al. F ibrolamellar hepat oc ellular c arc inoma. Radiology . 1985;157:583–587. 222. F riedman SL, Millw ard- Sadler GH, Art hur MJP. Liv er f ibrosis and c irrhosis.

In: Millw ard- Sadler GH WR, Art hur MJP, eds. Wr ight 's liv er and biliar y disease. Philadelphia: WB Saunders, 1992: 822–881. 223. F ulc her AS, Szuc s RA, Bassignani MJ, et al. Right lobe liv ing donor liv er t ransplant at ion: preoperat iv e ev aluat ion of t he donor w it h MR imaging. AJR Am J Roent genol. 2001;176:1483–1491. 224. F urui S, It ai Y , Oht omo K, et al. Hepat ic epit helioid hemangioendot helioma: report of f iv e c ases. Radiology . 1989;171:63–68. 225. F urut a A, It o K, F ujit a T , et al. Hepat ic enhanc ement in mult iphasic c ont rast - enhanc ed MDCT : c omparison of high- and low - iodine- c onc ent rat ion c ont rast medium in same pat ient s w it h c hronic liv er disease. AJR Am J Roent genol. 2004;183:157–162. 226. Gaa J, Saini S, F erruc c i JT . Perf usion c harac t erist ic s of hepat ic c av ernous hemangioma using int rav enous CT angiography (IVCT A). Eur J Radiol. 1991;12:228–233.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1956

12 - Liver 227. Gaa J, Hat abu H, Jenkins RL, et al. Liv er masses: replac ement of c onv ent ional T 2- w eight ed spin- ec ho MR imaging w it h breat h- hold MR imaging. Radiology . 1996;200:459–464. 228. Gabat a T , Kadoy a M, Mat sui O, et al. Perit umoral spared area in f at t y liv er: c orrelat ion bet w een opposed- phase gradient - ec ho MR imaging and CT art eriography . Abdom Im aging. 2001;26: 384–389.

229. Gandon Y , Guy ader D, Heaut ot JF , et al. Hemoc hromat osis: diagnosis and quant if ic at ion of liv er iron w it h gradient - ec ho MR imaging. Radiology . 1994;193:533–538. 230. Garc ia PA, Bonaldi VM, Bret PM, et al. Ef f ec t of rat e of c ont rast medium injec t ion on hepat ic enhanc ement at CT . Radiology . 1996;199:185–189. 231. Gazelle GS, Lee MJ, Hahn PF , et al. US, CT , and MRI of primary and sec ondary liv er ly mphoma. J Com put Assist T om ogr . 1994;18: 412–415. 232. Georgiades CS, Ney man EG, Barish MA, et al. Amy loidosis: rev iew and CT manif est at ions. Radiogr aphic s. 2004;24:405–416. 233. Gibney RG, Hendin AP, Cooperberg PL. Sonographic ally det ec t ed hepat ic hemangiomas: absenc e of c hange ov er t ime. AJR Am J Roent genol. 1987;149:953–957. 234. Giorgio A, Amoroso P, Let t ieri G, et al. Cirrhosis: v alue of c audat e t o right lobe rat io in diagnosis w it h US. Radiology . 1986;161: 443–445. 235. Giov agnoni A, T erilli F , Erc olani P, et al. MR imaging of hepat ic masses: diagnost ic signif ic anc e of w edge- shaped areas of inc reased signal int ensit y surrounding t he lesion. AJR Am J Roent genol. 1994; 163:1093–1097. 236. Git lin N, Serio KM. Isc hemic hepat it is: w idening horizons. Am J Gast r oent er ol. 1992;87:831–836. 237. Glazer GM, Aisen AM, F ranc is IR, et alD. Hepat ic c av ernous hemangioma: magnet ic resonanc e imaging. Work in progress. Radiology . 1985;155:417–420. 238. Gloc kner JF , F orauer AR, Solomon H, et al. T hree- dimensional gadoliniumenhanc ed MR angiography of v asc ular c omplic at ions af t er liv er t ransplant at ion. AJR Am J Roent genol. 2000;174: 1447–1453. P.917 239. Goldberg HI, Cann CE, Moss AA, et al. Noninv asiv e quant it at ion of liv er iron in dogs w it h hemoc hromat osis using dual- energy CT sc anning. Inv est Radiol. 1982;17:375–380.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1957

12 - Liver 240. Goldberg SN, Gazelle GS, Mueller PR. T hermal ablat ion t herapy f or f oc al malignanc y : a unif ied approac h t o underly ing princ iples, t ec hniques, and diagnost ic imaging guidanc e. AJR Am J Roent genol. 2000;174:323–331. 241. Goldman IS, Winkler ML, Raper SE, et al. Inc reased hepat ic densit y and phospholipidosis due t o amiodarone. AJR Am J Roent genol. 1985;144:541–546. 242. Goldsmit h M, Woodburne R. Surgic al anat omy pert aining t o liv er resec t ion. Sur g Gy nec ol Obst et . 1957;141:429–437. 243. Gomori JM, Horev G, T amary H, et al. Hepat ic iron ov erload: quant it at iv e MR imaging. Radiology . 1991;179:367–369. 244. Goodman ZD, Ishak KG. Angiomy olipomas of t he liv er. Am J Sur g Pat hol. 1984;8:745–750. 245. Goodman ZD, Mikel UV, Lubbers PR, et al. Kupf f er c ells in hepat oc ellular adenomas. Am J Sur g Pat hol. 1987;11:191–196. 246. Gordon S, Reddy K, Liv ingst one A. Resolut ion of a c ont rac ept iv e st eroid induc ed hepat ic adenoma w it h subsequent ev olut ion int o hepat oc ellular c arc inoma. Ann Int er n Med. 1986;105:547–549. 247. Gore RM, Vogelzang RL, Nemc ek AA Jr. Ly mphadenopat hy in c hronic ac t iv e hepat it is: CT observ at ions. AJR Am J Roent genol. 1988;151:75–78. 248. Gouy a H, Vignaux O, Legmann P, et al. Peliosis hepat is: t riphasic helic al CT and dy namic MRI f indings. Abdom Im aging. 2001;26: 507–509. 249. Graf O, Doc k WI, Lammer J, et al. Det erminat ion of opt imal t ime w indow f or liv er sc anning w it h CT during art erial port ography . Radiology . 1994;190:43–47. 250. Grandin C, Van Beers BE, Robert A, et al. Benign hepat oc ellular t umors: MRI af t er superparamagnet ic iron oxide administ rat ion. J Com put Assist T om ogr . 1995;19:412–418. 251. Grazioli L, F ederle MP, Ic hikaw a T , et al. Liv er adenomat osis: c linic al, hist opat hologic , and imaging f indings in 15 pat ient s. Radiology . 2000;216:395–402. 252. Grazioli L, F ederle MP, Branc at elli G, et al. Hepat ic adenomas: imaging and pat hologic f indings. Radiogr aphic s. 2001;21:877–892; disc ussion 892–874. 253. Grazioli L, Morana G, F ederle MP, et al. F oc al nodular hy perplasia: morphologic and f unc t ional inf ormat ion f rom MR imaging w it h gadobenat e dimeglumine. Radiology . 2001;221:731–739.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1958

12 - Liver 254. Grazioli L, Morana G, Kirc hin MA, et al. MRI of f oc al nodular hy perplasia (F NH) w it h gadobenat e dimeglumine (Gd- BOPT A) and SPIO (f erumoxides): an int ra- indiv idual c omparison. J Magn Reson Im aging. 2003;17:593–602.

255. Grossholz M, T errier F , Rubbia L, et al. F oc al sparing in t he f at t y liv er as a sign of an adjac ent spac e- oc c upy ing lesion. AJR Am J Roent genol. 1998;171:1391–1395. 256. Guy ader D, Gandon Y , Deugnier Y , et al. Ev aluat ion of c omput ed t omography in t he assessment of liv er iron ov erload. A st udy of 46 c ases of idiopat hic hemoc hromat osis. Gast r oent er ology . 1989;97:737–743. 257. Haider MA, Amit ai MM, Rappaport DC, et al. Mult i- det ec t or row helic al CT in preoperat iv e assessment of small (< or = 1.5 c m) liv er met ast ases: is t hinner c ollimat ion bet t er? Radiology . 2002;225: 137–142. 258. Halv orsen RA, Korobkin M, Ram PC, et al. CT appearanc e of f oc al f at t y inf ilt rat ion of t he liv er. AJR Am J Roent genol. 1982;139: 277–281. 259. Hamm B, Vogl T J, Branding G, et al. F oc al liv er lesions: MR imaging w it h Mn- DPDP–init ial c linic al result s in 40 pat ient s. Radiology . 1992;182:167–174. 260. Hamm B, T hoeni RF , Gould RG, et al. F oc al liv er lesions: c harac t erizat ion w it h nonenhanc ed and dy namic c ont rast mat erial- enhanc ed MR imaging. Radiology . 1994;190:417–423. 261. Hamm B, Mahf ouz AE, T aupit z M, et al. Liv er met ast ases: improv ed det ec t ion w it h dy namic gadolinium- enhanc ed MR imaging? Radiology . 1997;202:677–682. 262. Hamm B, Kirc hin M, Pirov ano G, et al. Clinic al ut ilit y and saf et y of Mult iHanc e in magnet ic resonanc e imaging of liv er c anc er: result s of mult ic ent er st udies in Europe and t he USA. J Com put Assist T om ogr . 1999;23 Suppl 1:S53–S60. 263. Hamric k- T urner J, Abbit t PL, Ros PR. Int rahepat ic c holangioc arc inoma: MR appearanc e. AJR Am J Roent genol. 1992;158: 77–79. 264. Hamric k- T urner JE, Shipkey F H, Cranst on PE. F ibrolamellar hepat oc ellular c arc inoma: MR appearanc e mimic king f oc al nodular hy perplasia. J Com put Assist T om ogr . 1994;18:301–304. 265. Hanaf usa K, Ohashi I, Himeno Y , et al. Hepat ic hemangioma: f indings w it h t w o- phase CT . Radiology . 1995;196:465–469. 266. Harbin WP, Robert NJ, F erruc c i JT Jr. Diagnosis of c irrhosis based on regional c hanges in hepat ic morphology : a radiologic al and pat hologic al analy sis. Radiology . 1980;135:273–283.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1959

12 - Liver 267. Harmon BH, Berland LL, Lee JY . Ef f ec t of v ary ing rat es of low - osmolarit y c ont rast media injec t ion f or hepat ic CT : c orrelat ion w it h indoc y anine green t ransit t ime. Radiology . 1992;184:379–382.

268. Hart er LP, Gross BH, St Hilaire J, et al. CT and sonographic appearanc e of hepat ic v ein obst ruc t ion. AJR Am J Roent genol. 1982; 139:176–178. 269. Hat t en MT , Hamric k- T urner JE. Segment al hepat ic nec rosis af t er blunt abdominal t rauma: CT f indings. AJR Am J Roent genol. 1996; 167:769–770. 270. Hay ashi M, Mat sui O, Ueda K, et al. Correlat ion bet w een t he blood supply and grade of malignanc y of hepat oc ellular nodules assoc iat ed w it h liv er c irrhosis: ev aluat ion by CT during int raart erial injec t ion of c ont rast medium. AJR Am J Roent genol. 1999;172:969–976. 271. Heiken JP, Bae KT . Cont rast medium administ rat ion and sc an t iming f or MDCT . In: Marc hal G, Vogl T J, Heiken JP, et al., eds. Mult idec t or -r ow c om put ed t om ogr aphy . Milan, It aly : Springer- Verlag It alia, 2005:13. 272. Heiken JP, Lee JK, Dixon WT . F at t y inf ilt rat ion of t he liv er: ev aluat ion by prot on spec t rosc opic imaging. Radiology . 1985;157:707–710. 273. Heiken JP, Wey man PJ, Lee JK, et al. Det ec t ion of f oc al hepat ic masses: prospec t iv e ev aluat ion w it h CT , delay ed CT , CT during art erial port ography , and MR imaging. Radiology . 1989;171:47–51. 274. Heiken JP, Brink JA, Mc Clennan BL, et al. Dy namic c ont rast - enhanc ed CT of t he liv er: c omparison of c ont rast medium injec t ion rat es and uniphasic and biphasic injec t ion prot oc ols. Radiology . 1993;187:327–331. 275. Heiken JP, Brink JA, Mc Clennan BL, et al. Dy namic inc rement al CT : ef f ec t of v olume and c onc ent rat ion of c ont rast mat erial and pat ient w eight on hepat ic enhanc ement . Radiology . 1995;195:353–357. 276. Helmberger T , Semelka RC. New c ont rast agent s f or imaging t he liv er. Magn Reson Im aging Clin N Am . 2001;9:745–766, v i. 277. Hemming AW, Cat t ral MS, Reed AI, et al. Liv er t ransplant at ion f or hepat oc ellular c arc inoma. Ann Sur g. 2001;233:652–659. 278. Herc ules HD, Bet hlem NM. Value of liv er biopsy in sarc oidosis. Ar c h Pat hol Lab Med. 1984;108:831–834. 279. Heuc k A, Mat t ke S, Seemann M, et al. Inc reased liv er densit y in c omput ed t omography as a result of ant i- arrhy t hmia t herapy w it h amiodarone. Rof o. 1997;166:14–17. 280. Hill SC, Damaska BM, Ling A, et al. Gauc her disease: abdominal MR imaging f indings in 46 pat ient s. Radiology . 1992;184:561–566.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1960

12 - Liver

281. Hof f F L, Aisen AM, Walden ME, et al. MR imaging in hy dat id disease of t he liv er. Gast r oint est Radiol. 1987;12:39–42. 282. Holbert BL, Baron RL, Dodd GD III. Hepat ic inf arc t ion c aused by art erial insuf f ic ienc y : spec t rum and ev olut ion of CT f indings. AJR Am J Roent genol. 1996;166:815–820. 283. Hollet t MD, Jef f rey RB Jr, Nino- Murc ia M, et al. Dual- phase helic al CT of t he liv er: v alue of art erial phase sc ans in t he det ec t ion of small (< or = 1.5 c m) malignant hepat ic neoplasms. AJR Am J Roent genol. 1995;164:879–884. 284. Holley HC, Koslin DB, Berland LL, et al. Inhomogeneous enhanc ement of liv er parenc hy ma sec ondary t o passiv e c ongest ion: c ont rast - enhanc ed CT . Radiology . 1989;170:795–800. 285. Honda H, F ranken EA Jr, Barloon T J, et al. Hepat ic ly mphoma in c y c losporine- t reat ed t ransplant rec ipient s: sonographic and CT f indings. AJR Am J Roent genol. 1989;152:501–503. 286. Honda H, Barloon T J, F ranken EA Jr, et al. Clinic al and radiologic f eat ures of malignant neoplasms in organ t ransplant rec ipient s: c y c losporine- t reat ed v s unt reat ed pat ient s. AJR Am J Roent genol. 1990;154:271–274. 287. Honda H, Onit suka H, Y asumori K, et al. Int rahepat ic peripheral c holangioc arc inoma: t w o- phased dy namic inc rement al CT and pat hologic c orrelat ion. J Com put Assist T om ogr . 1993;17:397–402. P.918 288. Hooper LD, Mergo PJ, Ros PR. Mult iple hepat orenal angiomy olipomas: diagnosis w it h f at suppression, gadolinium- enhanc ed MRI. Abdom Im aging. 1994;19:549–551. 289. Hort on KM, Bluemke DA, Hruban RH, et al. CT and MR imaging of benign hepat ic and biliary t umors. Radiogr aphic s. 1999;19: 431–451. 290. Hoshiba K, Mat sui O, Kadoy a M, et al. Peribiliary c y st s in c irrhot ic liv er: observ at ion on c omput ed t omography . Abdom Im aging. 1996;21:228–232. 291. How ard JM, Ghent CN, Carey LS, et al. Diagnost ic ef f ic ac y of hepat ic c omput ed t omography in t he det ec t ion of body iron ov erload. Gast r oent er ology . 1983;84:209–215. 292. How ell RR, St ev enson RE, Ben- Menac hem Y , et al. Hepat ic adenomat a w it h t y pe 1 gly c ogen st orage disease. JAMA. 1976;236: 1481–1484. 293. Huppert z A, Balzer T , Blakeborough A, et al. Improv ed det ec t ion of f oc al liv er lesions at MR imaging: mult ic ent er c omparison of gadoxet ic ac idenhanc ed MR images w it h int raoperat iv e f indings. Radiology . 2004;230:266–275.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1961

12 - Liver 294. Huppert z A, Haraida S, Kraus A, et al. Enhanc ement of f oc al liv er lesions at gadoxet ic ac id- enhanc ed MR imaging: c orrelat ion w it h hist opat hologic f indings and spiral CT —init ial observ at ions. Radiology . 2005;234:468–478.

295. Hussain HK, Londy F J, F ranc is IR, et al. Hepat ic art erial phase MR imaging w it h aut omat ed bolus- det ec t ion t hree- dimensional f ast gradient - rec alled- ec ho sequenc e: c omparison w it h t est - bolus met hod. Radiology . 2003;226:558–566. 296. Hussain SM, Zonderv an PE, JN IJ, et al. Benign v ersus malignant hepat ic nodules: MR imaging f indings w it h pat hologic c orrelat ion. Radiogr aphic s. 2002;22:1023–1036. 297. Hussain SM, T erkiv at an T , Zonderv an PE, et al. F oc al nodular hy perplasia: f indings at st at e- of - t he- art MR imaging, US, CT , and pat hologic analy sis. Radiogr aphic s. 2004;24:3–17. 298. Hw ang GJ, Kim MJ, Y oo HS, et al. Nodular hepat oc ellular c arc inomas: det ec t ion w it h art erial- , port al- , and delay ed- phase images at spiral CT . Radiology . 1997;202:383–388. 299. Iannac c one R, Laghi A, Cat alano C, et al. Hepat oc ellular c arc inoma: role of unenhanc ed and delay ed phase mult i- det ec t or row helic al CT in pat ient s w it h c irrhosis. Radiology . 2005;234: 460–467. 300. Ic hikaw a T , F ederle MP, Grazioli L, et al. F ibrolamellar hepat oc ellular c arc inoma: imaging and pat hologic f indings in 31 rec ent c ases. Radiology . 1999;213:352–361. 301. Ic hikaw a T , F ederle MP, Grazioli L, et al. F ibrolamellar hepat oc ellular c arc inoma: pre- and post t herapy ev aluat ion w it h CT and MR imaging. Radiology . 2000;217:145–151. 302. Ic hikaw a T , F ederle MP, Grazioli L, et al. Hepat oc ellular adenoma: mult iphasic CT and hist opat hologic f indings in 25 pat ient s. Radiology . 2000;214:861–868. 303. Ikeda M, Sekimot o M, T akiguc hi S, et al. High inc idenc e of t hrombosis of t he port al v enous sy st em af t er laparosc opic splenec t omy : a prospec t iv e st udy w it h c ont rast - enhanc ed CT sc an. Ann Sur g. 2005;241:208–216. 304. Inamot o K, Sugiki K, Y amasaki H, et al. CT of hepat oma: ef f ec t s of port al v ein obst ruc t ion. AJR Am J Roent genol. 1981;136: 349–353. 305. Inoue E, Kuroda C, F ujit a M, et al. MR f eat ures of v arious hist ologic al grades of small hepat oc ellular c arc inoma. J Com put Assist T om ogr . 1993;17:75–79.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1962

12 - Liver 306. Int ernat ional Working Part y WCoG. T erminology of nodular hepat oc ellular lesions. Int ernat ional Working Part y . Hepat ology . 1995;22:983–993. 307. Irie T , T akeshit a K, Wada Y , et al. CT ev aluat ion of hepat ic t umors: c omparison of CT w it h art erial port ography , CT w it h inf usion hepat ic

art eriography , and simult aneous use of bot h t ec hniques. AJR Am J Roent genol. 1995;164:1407–1412. 308. Ishak KG, Willis GW, Cummins SD, et al. Biliary c y st adenoma and c y st adenoc arc inoma: report of 14 c ases and rev iew of t he lit erat ure. Canc er . 1977;39:322–338. 309. Ishak KG. Hepat ic lesions c aused by anabolic and c ont rac ept iv e st eroids. Sem in Liv er Dis. 1981;1:116–128. 310. Ishak KG, Sest erhenn IA, Goodman ZD, et al. Epit helioid hemangioendot helioma of t he liv er: a c linic opat hologic and f ollow - up st udy of 32 c ases. Hum Pat hol. 1984;15:839–852. 311. Ishikaw a T , T sukune Y , Ohy ama Y , et al. Venous abnormalit ies in port al hy pert ension demonst rat ed by CT . AJR Am J Roent genol. 1980;134:271–276. 312. It ai Y , F urui S, Araki T , et al. Comput ed t omography of c av ernous hemangioma of t he liv er. Radiology . 1980;137:149–155. 313. It ai Y , Araki T , F urui S, et al. Dif f erent ial diagnosis of hepat ic masses on c omput ed t omography , w it h part ic ular ref erenc e t o hepat oc ellular c arc inoma. J Com put Assist T om ogr . 1981;5:834–842. 314. It ai Y , Moss AA, Goldberg HI. T ransient hepat ic at t enuat ion dif f erenc e of lobar or segment al dist ribut ion det ec t ed by dy namic c omput ed t omography . Radiology . 1982;144:835–839. 315. It ai Y , Oht omo K, F urui S, et al. Noninv asiv e diagnosis of small c av ernous hemangioma of t he liv er: adv ant age of MRI. AJR Am J Roent genol. 1985;145:1195–1199. 316. It ai Y , F urui S, Oht omo K, et al. Dy namic CT f eat ures of art erioport al shunt s in hepat oc ellular c arc inoma. AJR Am J Roent genol. 1986;146:723–727. 317. It ai Y , Oht omo K, Kokubo T , et al. CT of hepat ic masses: signif ic anc e of prolonged and delay ed enhanc ement . AJR Am J Roent genol. 1986;146:729–733. 318. It ai Y , Hac hiy a J, Makit a K, et al. T ransient hepat ic at t enuat ion dif f erenc es on dy namic c omput ed t omography . J Com put Assist T om ogr . 1987;11:461–465.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1963

12 - Liver

319. It ai Y , Ohnishi S, Oht omo K, et al. Regenerat ing nodules of liv er c irrhosis: MR imaging. Radiology . 1987;165:419–423. 320. It ai Y , Oht omo K, Kokubo T , et al. Segment al int ensit y dif f erenc es in t he liv er on MR images: a sign of int rahepat ic port al f low st oppage. Radiology . 1988;167:17–19. 321. It ai Y , T eraoka T . Angiosarc oma of t he liv er mimic king c av ernous hemangioma on dy namic CT . J Com put Assist T om ogr . 1989;13: 910–912. 322. It ai Y , Ebihara R, T ohno E, et al. Hepat ic peribiliary c y st s: mult iple t iny c y st s w it hin t he larger port al t rac t , hepat ic hilum, or bot h. Radiology . 1994;191:107–110. 323. It ai Y , Mat sui O. Blood f low and liv er imaging. Radiology . 1997; 202:306–314. 324. It ai Y , Mat sui O. “ Nonport al” splanc hnic v enous supply t o t he liv er: abnormal f indings on CT , US and MRI. Eur Radiol. 1999;9: 237–243. 325. It o K, Mit c hell DG, Hann HW, et al. Progressiv e v iral- induc ed c irrhosis: serial MR imaging f indings and c linic al c orrelat ion. Radiology . 1998;207:729–735. 326. It o K, Mit c hell DG, Gabat a T , et al. Hepat oc ellular c arc inoma: assoc iat ion w it h inc reased iron deposit ion in t he c irrhot ic liv er at MR imaging. Radiology . 1999;212:235–240. 327. It o K, Mit c hell DG, Gabat a T , et al. Expanded gallbladder f ossa: simple MR imaging sign of c irrhosis. Radiology . 1999;211: 723–726. 328. It o K, Mit c hell DG, Gabat a T . Enlargement of hilar periport al spac e: a sign of early c irrhosis at MR imaging. J Magn Reson Im aging. 2000;11:136–140. 329. It o K, Siegelman ES, St olpen AH, et al. MR imaging of c omplic at ions af t er liv er t ransplant at ion. AJR Am J Roent genol. 2000;175: 1145–1149. 330. It o K, Mit c hell DG, Kim MJ, et al. Right post erior hepat ic not c h sign: a simple diagnost ic MR f inding of c irrhosis. J Magn Reson Im aging. 2003;18:561–566. 331. It oh H, Sakai T , T akahashi N, et al. Periport al high int ensit y on T 2w eight ed MR images in ac ut e v iral hepat it is. J Com put Assist T om ogr . 1992;16:564–567. 332. It oh K, Nishimura K, T ogashi K, et al. Hepat oc ellular c arc inoma: MR imaging. Radiology . 1987;164:21–25. 333. It oh S, Ikeda M, Ac hiw a M, et al. Mult iphase c ont rast - enhanc ed CT of t he liv er w it h a mult islic e CT sc anner. Eur Radiol. 2003;13: 1085–1094.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

1964

12 - Liver 334. Jac obs JE, Birnbaum BA, Shapiro MA, et al. Diagnost ic c rit eria f or f at t y

inf ilt rat ion of t he liv er on c ont rast - enhanc ed helic al CT . AJR Am J Roent genol. 1998;171:659–664. 335. Jang HJ, Choi BI, Kim T K, et al. At y pic al small hemangiomas of t he liv er: “ bright dot ” sign at t w o- phase spiral CT . Radiology . 1998; 208:543–548. 336. Jang HJ, Lim JH, Lee SJ, et al. Hepat oc ellular c arc inoma: are c ombined CT during art erial port ography and CT hepat ic art eriography in addit ion t o t riplephase helic al CT all nec essary f or preoperat iv e ev aluat ion? Radiology . 2000;215:373–380. P.919 337. Jang HJ, Lim HK, Lee WJ, et al. Small hy poat t enuat ing lesions in t he liv er on single- phase helic al CT in preoperat iv e pat ient s w it h gast ric and c olorec t al c anc er: prev alenc e, signif ic anc e, and dif f erent iat ing f eat ures. J Com put Assist T om ogr . 2002;26: 718–724. 338. Jef f rey RB Jr, Moss AA, Quiv ey JM, et al. CT of radiat ion- induc ed hepat ic injury . AJR Am J Roent genol. 1980;135:445–448. 339. Jef f rey RB Jr, T olent ino CS, Chang F C, et al. CT of small py ogenic hepat ic absc esses: t he c lust er sign. AJR Am J Roent genol. 1988;151: 487–489. 340. Jennings CM, Merrill CR, Slat er DN. T he c omput ed t omographic appearanc es of benign hepat ic hamart oma. Clin Radiol. 1987;38: 103–104. 341. Jeong Y Y , Mit c hell DG, Kamishima T . Small ( T able of Cont ent s > 13 - T he Biliary T rac t

13 The Biliary Tract F ra nklin N. Te ssle r Ma rk E. Loc kha rt Dedic at ed c omput ed t omography (CT ) of t he gallbladder and bile duc t s is most of t en perf ormed in t he c linic al set t ing of know n or suspec t ed biliary obst ruc t ion. CT has also c ome t o play an inc reasingly import ant role in a v ariet y of ot her c ondit ions, suc h as c ongenit al anomalies, inf lammat ory proc esses, and neoplasms. In addit ion, CT is of t en used t o ev aluat e t he sec ondary ef f ec t s of nonbiliary pat hology , not ably panc reat ic neoplasms, on t he biliary sy st em. Hist oric ally , CT has c ompet ed w it h est ablished c ont rast - based imaging proc edures, inc luding oral c holec y st ography , int rav enous c holangiography , perc ut aneous t ranshepat ic c holangiography (PT C), and endosc opic ret rograde c holangiopanc reat ography (ERCP), all of w hic h prov ide exc ellent det ail w it hin t he c onf ines of t he biliary t rac t but are limit ed by t heir inabilit y t o direc t ly v isualize st ruc t ures bey ond t he opac if ied lumen. Radionuc lide biliary sc int igraphy , w hic h prov ides f unc t ional inf ormat ion at t he expense of poorer spat ial resolut ion, and sonography , w hic h has gained ac c ept anc e bec ause of it s relat iv ely low c ost and ready av ailabilit y , also c ont inue t o be w idely used. Most t radit ional imaging st udies are st ill of f ered t oday , and indeed some hav e expanded t heir roles as new er v ariant s, suc h as endosc opic ult rasound (EUS), hav e appeared. In rec ent y ears, magnet ic resonanc e imaging (MRI) and magnet ic resonanc e c holangiopanc reat ography (MRCP) hav e been added t o t he diagnost ic armament arium used t o ev aluat e pat ient s w it h biliary disease. MRCP, in part ic ular, has seen grow ing applic at ion as a replac ement f or inv asiv e t radit ional t ec hniques suc h as ERCP and PT C. F ac ed w it h an ev er- expanding c hoic e of imaging t est s, t he c hallenge f or t he c linic ian and t he imaging spec ialist alike is t o det ermine w hic h imaging

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2011

13 - The Biliary Tract modalit y t o use f or a giv en pat ient and, in c ases f or w hic h mult iple st udies must be perf ormed, t o know w hat sequenc e t o use. T his c hapt er rev iew s t he basic anat omy and t he normal and abnormal phy siology of t he biliary t rac t . Next , t he role of CT and MRI in ev aluat ing pat ient s w it h biliary disease is

disc ussed. Alt hough a det ailed disc ussion of ot her imaging modalit ies is bey ond t he sc ope of t his c hapt er, t he c omplement ary role of t est s suc h as sonography and EUS is desc ribed w hen appropriat e.

NORMAL ANATOMY AND VARIATIONS In most indiv iduals, t he right ant erior and post erior segment al int rahepat ic bile duc t s c onv erge t o f orm t he right hepat ic duc t , w hic h joins t he lef t hepat ic duc t t o f orm t he c ommon hepat ic duc t (CHD). T he gallbladder, drained by t he c y st ic duc t , is usually loc at ed at t he inf erior margin of t he liv er in a plane def ined by t he int erlobar f issure. T he c y st ic duc t insert s int o t he CHD, w hic h c ont inues on as t he c ommon bile duc t (CBD). At t he ampulla of Vat er, t he CBD t y pic ally joins t he main panc reat ic duc t . Anat omic v ariat ions of biliary drainage are c ommon, how ev er, and hav e part ic ular signif ic anc e in pat ient s w ho are prospec t iv e liv ing liv er donors. In a rec ent st udy of 300 donors w ho underw ent int raoperat iv e c holangiography , sev en dif f erent t y pes of int rahepat ic branc hing pat t erns w ere desc ribed, w it h t he prev iously not ed c onf igurat ion f ound in only 63% of c ases (38). In t he sec ond most c ommon pat t ern, w hic h w as f ound in 11% of c ases, t he right post erior segment al duc t empt ied direc t ly int o eit her t he CHD or t he lef t hepat ic duc t . Almost as c ommon w as a t hird pat t ern, in w hic h t he right ant erior and post erior duc t s joined t he lef t hepat ic duc t at a single point . Ot her v ariat ions, w hic h inc luded drainage of t he right hepat ic duc t or ac c essory duc t s int o t he c y st ic duc t , w ere seen less of t en. Mult iple v ariat ions of gallbladder anat omy hav e also been desc ribed. T he most f requent anomaly is t he so- c alled “ Phry gian c ap,” in w hic h t he gallbladder f undus has a f olded c onf igurat ion (as disc ussed lat er in t his c hapt er) (132). P.932 Complet e agenesis of t he gallbladder is exc eedingly rare, w it h a report ed inc idenc e of less t han one in 6,000 liv e birt hs (172). Sept at ion, duplic at ion, and t riplic at ion of t he gallbladder are slight ly more c ommon (132). Various sit es of ec t opic gallbladder dev elopment , inc luding int rahepat ic and suprahepat ic loc at ions, hav e also been report ed (261,267), as has herniat ion

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2012

13 - The Biliary Tract of t he gallbladder t hrough t he f oramen of Winslow int o t he lesser sac (16).

Likew ise, v ariat ions of c y st ic duc t anat omy are c ommon. T he c y st ic duc t may empt y int o t he CHD any w here along it s c ourse, f rom t he c onf luenc e t o t he ampulla. Direc t c ommunic at ion bet w een t he int rahepat ic bile duc t s and t he c y st ic duc t also may oc c ur. F inally , malrot at ion of t he c y st ic duc t c an c ause it t o f orm a loop ant erior or post erior t o t he CHD (217).

PATHOPHYSIOLOGY OF BILIARY OBSTRUCTION Bile f ormat ion is a c omplex proc ess t hat begins w it h t he sec ret ion of primary bile by t he hepat oc y t es (233). Bile t hen passes along t he int rahepat ic duc t s, w hic h modif y it ext ensiv ely . T he gallbladder f urt her modif ies t he bile by c onc ent rat ing and ac idif y ing it bef ore exc ret ing it int o t he CBD and henc e int o t he duodenum. Any proc ess t hat result s in exc essiv e ac c umulat ion of bilirubin w it hin t he blood serum (hy perbilirubinemia) result s in a spec t rum of c linic al manif est at ions, w hic h inc lude jaundic e (a y ellow ish disc olorat ion of t he skin), sc leral ic t erus, dark urine, and light st ools (154). Jaundic e appears w hen t he serum bilirubin lev el is great er t han 2 t o 4 mg/dL. T he primary role of biliary imaging is t o dist inguish obst ruc t iv e f rom nonobst ruc t iv e hy perbilirubinemia, w hic h is a diagnosis largely based on t he det ec t ion of anat omic c hanges in t he biliary t rac t in response t o obst ruc t ion. T he earliest suc h c hange is an inc rease in t he diamet er of t he CBD (154), w hic h usually measures no great er t han 6 or 7mm in normal adult s (56). T he t ime c ourse f or t he dev elopment of biliary dilat at ion is v ariable, and t he degree of dilat at ion also depends on w het her t he obst ruc t ion is c ont inuous or int ermit t ent . Import ant ly , biliary dilat at ion may be minimal early in t he c ourse of obst ruc t ion. Conv ersely , pat ient s w ho hav e had a c holec y st ec t omy may hav e a dilat ed CBD in t he absenc e of f unc t ional obst ruc t ion (108). If biliary obst ruc t ion is not reliev ed, int rahepat ic biliary dilat at ion and enlargement of t he gallbladder usually f ollow . Again, how ev er, t he t ime c ourse f or t hese anat omic c hanges t o oc c ur is quit e v ariable. As w ell, t he int rinsic abilit y of t hese st ruc t ures t o dilat e in response t o inc reased biliary pressure v aries depending on t heir int rinsic c omplianc e and on t he c omplianc e of adjac ent t issues and st ruc t ures. F or example, int rahepat ic bile duc t s in c irrhot ic liv ers w it h ext ensiv e f ibrosis may be less able t o expand in t he set t ing of biliary obst ruc t ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2013

13 - The Biliary Tract GENERAL PRINCIPLES OF BILIARY IMAGING T he c hoic e and sequenc e of imaging t est s in pat ient s w it h biliary disease is based on t he c linic al sy mpt oms and signs, as w ell as f indings on init ial laborat ory t est ing. A posit iv e sc reening st udy is of t en f urt her ev aluat ed w it h a more spec if ic inv asiv e t est , suc h as ERCP or PT C. How ev er, a f alse posit iv e

result may nec essit at e addit ional st udies t o y ield a diagnosis, w it h assoc iat ed addit ional c ost and risks. T heref ore, t he pot ent ial risks must be balanc ed against t he need f or a diagnosis in t he indiv idual pat ient . Noninv asiv e imaging t ec hniques inc lude ult rasound, CT , MRI, and nuc lear medic ine st udies. Sonography is of t en t he init ial imaging st udy t o ev aluat e abnormal biliary laborat ory t est s bec ause of it s low c ost , port abilit y , and lac k of ionizing radiat ion, w hic h f ac ilit at e it s use at t he bedside. Ult rasound is highly sensit iv e f or det ec t ing biliary obst ruc t ion, and it is also v ery usef ul f or det ec t ing c holelit hiasis, c holedoc olit hiasis, or ac ut e c holec y st it is (25,162,163,200). How ev er, ult rasound of t en has limit ed spec if ic it y in pat ient s w it h biliary obst ruc t ion, and it s sensit iv it y is limit ed in obese pat ient s (184). Moreov er, t he c linic al inf ormat ion gained f rom sonography depends great ly upon t he skill of t he operat or w ho perf orms t he st udy and t he phy sic ian w ho int erpret s t he images. Nuc lear c holesc int igraphy is a noninv asiv e t ec hnique t hat lac ks t he spat ial resolut ion of t he ot her imaging modalit ies, but it c an be v ery ac c urat e in t he diagnosis of c y st ic duc t obst ruc t ion (146). Cholesc int igraphy c an ac c urat ely diagnose ac ut e c holec y st it is, and it also may c harac t erize ac alc ulous c holec y st it is (50). How ev er, c holesc int igraphy is limit ed in pat ient s w ho are rec eiv ing t ot al parent al nut rit ion or w ho are c hronic ally hospit alized. MRI prov ides exc ellent anat omic det ail and c ont rast resolut ion, also w it hout t he use of ionizing radiat ion. MRI may det ec t most biliary abnormalit ies, and it is of t en pref erred in plac e of ERCP if t here is low suspic ion t hat int erv ent ion w ill be needed. MRCP is able t o demonst rat e nonc alc if ied gallst ones as f illing def ec t s, but it may be less sensit iv e t han CT f or c alc if ic at ions (101). Unf ort unat ely , MRCP may be more susc ept ible t o art if ac t s assoc iat ed w it h breat hing or mot ion, w hic h may be limit ing in ill pat ient s w ho are unable t o suspend respirat ion or lie st ill on t he MRI c ouc h. As w ell, neit her MRI nor MRCP allow f or direc t ev aluat ion of t enderness, w hic h c an be a v aluable adjunc t iv e f inding on ult rasound in pat ient s w it h ac ut e c holec y st it is (221).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2014

13 - The Biliary Tract CT is not a f irst - line c hoic e in t he ev aluat ion of biliary c olic bec ause of it s c ost , lac k of port abilit y , and use of ionizing radiat ion. How ev er, CT may det ec t biliary dilat at ion, biliary w all t hic kening, duc t al st ones, panc reat ic mass, or adenopat hy . CT is v ery sensit iv e and spec if ic f or c alc if ied biliary duc t st ones, and it has exc ellent spat ial resolut ion (193). When t he et iology of sy mpt oms is not c onf ident ly loc alized t o t he biliary sy st em, CT is a robust t ec hnique t hat not only P.933

may loc alize a biliary abnormalit y , but may also det ec t a nonbiliary et iology f or t he pat ient 's sy mpt oms and signs. CT is also less susc ept ible t o mot ion art if ac t s t han MRI. If direc t ac t iv e ev aluat ion of t he bile duc t s or pat hologic diagnosis is nec essary , imaging w it h ERCP, PT C, or EUS may be perf ormed. ERCP and PT C are inv asiv e, but t hey prov ide t he great est anat omic and muc osal det ail of t he biliary duc t s. T hese t ec hniques suf f er f rom higher rat es of c omplic at ion, but t hey allow pot ent ial sampling f or malignant c ells. In ERCP, t he ampullary region is ac c essed endosc opic ally t o c annulat e t he bile duc t s and dist end t hem w it h c ont rast f or imaging. PT C similarly dist ends t he bile duc t s, but uses needle c annulat ion of an int rahepat ic duc t by plac ing a needle t hrough t he liv er parenc hy ma t ransc ut aneously . PT C is oc c asionally used f or diagnosis, but it is more c ommonly perf ormed t o drain biliary obst ruc t ion w hen t he biliary sy st em c annot be ac c essed by ERCP. ERCP and MRCP hav e signif ic ant dif f erent t ec hnic al c onsiderat ions t hat af f ec t t he appearanc e of t he biliary sy st em. ERCP dist ends t he biliary sy st em f rom t he CBD using c ont rast injec t ion, w hereas MRCP relies on det ec t ion of signal f rom bile w it hin t he duc t s w it hout dist ension w it h c ont rast . T heref ore, t he duc t s w ill be smaller and y ield less signal int ensit y in t he normal st at e on MRCP t han is present on ERCP. In c ont rast , ERCP may not be able t o c ross a biliary st ric t ure t o allow ev aluat ion of dilat ed int rahepat ic bile duc t s. In summary , w hen c onsidering a pat ient w it h pot ent ial biliary disease, a t horough hist ory , phy sic al examinat ion, and laborat ory ev aluat ion should be perf ormed. F or det ec t ion of gallst ones or ac ut e c holec y st it is, sonography is usually perf ormed, but CT or nuc lear medic ine st udies may y ield t he diagnosis. If t he c linic al suspic ion is biliary obst ruc t ion or jaundic e, sonography should be perf ormed init ially . If gallst ones are present on ult rasound, ERCP is perf ormed t o det ec t duc t al st ones and prov ide t herapy . If t he duc t c annot be c annulat ed, PT C may be perf ormed. If t here is no ev idenc e of gallst one

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2015

13 - The Biliary Tract disease on ult rasound, CT or MRI may be used t o ev aluat e f or c holangioc arc inoma or ot her neoplasm and searc h f or any ev idenc e of

met ast at ic disease. MRCP may be perf ormed init ially rat her t han sonography if t here is high c linic al suspic ion of sc lerosing c holangit is.

COMPUTED TOMOGRAPHY: TECHNIQUE AND NORMAL APPEARANCES Ev en prior t o t he dev elopment of helic al CT in t he 1990s, t he abilit y of axial CT t o image t he normal and abnormal gallbladder and bile duc t s w as w ell est ablished. Nev ert heless, CT w as rarely c onsidered as t he primary imaging modalit y in pat ient s w it h suspec t ed biliary obst ruc t ion, part ic ularly giv en t he ready av ailabilit y of ult rasound and t he subsequent abilit y of MRCP t o depic t t he biliary sy st em in exquisit e det ail. During rec ent y ears, how ev er, t he rapid deploy ment of helic al CT sc anners and inc reasing av ailabilit y of mult idet ec t or row CT has led t o an enhanc ed role f or CT imaging of biliary pat hology . Conc urrent ly , t here has been renew ed int erest in t he use of oral and int rav enous c ont rast agent s t o opac if y t he gallbladder and bile duc t s prior t o CT assessment . How ev er, bec ause t he lat t er t ec hnique has not been w idely ac c ept ed in c linic al prac t ic e, t his rev iew w ill begin by desc ribing t he princ iples of CT imaging of t he unopac if ied biliary t ree. Ev en in pat ient s w it h suspec t ed primary biliary pat hology , CT is usually perf ormed as muc h t o det ec t and c harac t erize abnormalit ies of t he nonbiliary organs and st ruc t ures (not ably t he liv er, t he panc reas, and adjac ent ly mph node c hains and v essels) as t o depic t t he bile duc t s t hemselv es. Consequent ly , it is v it al t hat any “ biliary ” CT t ec hnique t ake t his requirement int o ac c ount . T he examinat ion begins w it h f ront al and lat eral projec t ion sc out images, w hic h prov ide general anat omic landmarks f or imaging, and w hic h may oc c asionally demonst rat e malposit ioned st ent s or ot her inst rument s. Subsequent ly , unenhanc ed helic al CT images of t he upper abdomen are obt ained using 5- mm c ollimat ion during a single breat h- hold w it h a 1:1 pit c h. T his image set allow s t he operat or t o loc alize t he bile duc t s and panc reas and also f ac ilit at es ident if ic at ion of c alc if ic at ions w it hin t he panc reas, gallbladder, and bile duc t s. T he t y pe of oral c ont rast agent t o opac if y t he gast roint est inal t rac t is open t o debat e and depends, t o an ext ent , on anc illary indic at ions f or t he st udy . If t he CT examinat ion is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2016

13 - The Biliary Tract somew hat generalized in sc ope, it is best t o administ er w at er- soluble iodinat ed c ont rast orally prior t o sc anning. How ev er, if t he sc an is primarily direc t ed at t he bile duc t s or panc reas, t he use of w at er as a negat iv e oral “ c ont rast agent ” helps minimize art if ac t s and also inc reases t he sensit iv it y f or t he det ec t ion of abnormalit ies in t he duodenum and ampulla. Next , art erial and port al v enous phase imaging of t he upper abdomen is perf ormed during rapid int rav enous administ rat ion of 125 t o 150 mL of w at ersoluble c ont rast medium int o an ant ec ubit al or ot her suit able v ein at a f low rat e of 4 or 5 mL per sec ond. Imaging f rom t he hepat ic dome dow n t o t he port a hepat is uses 5 mm c ollimat ion, w hereas 2.5- mm or t hinner c ollimat ion is used f rom t his lev el dow n t hrough t he unc inat e proc ess of t he panc reas. In selec t ed c ases, t hin- sec t ion imaging c an be init iat ed higher in t he liv er t o f ac ilit at e subsequent mult iplanar ref ormat t ing or v olume rendering. Art erial phase imaging is perf ormed w it h a sc an delay of approximat ely 25 t o 30 sec onds af t er t he st art of injec t ion, w hereas port al v enous phase imaging begins at approximat ely 70 sec onds. T he delay t imes should be adjust ed upw ard in pat ient s w it h c ardiac disease or ot her c ondit ions t hat prolong t he c irc ulat ion t ime and low er in y ounger at hlet ic pat ient s. Alt hough not required

in all c ases, mult iplanar ref ormat t ing, maximum or minimum- int ensit y projec t ion images, or v olume- rendered images are of t en helpf ul t o c onf irm impressions based on rev iew of t he axial images or t o produc e display s t hat mimic MRCP or ERCP f or ref erring c linic ians (107,183) (F ig. 13- 1).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2017

13 - The Biliary Tract

F igure 13- 1 Comput ed t omography image ref ormat t ed in t he c oronal plane demonst rat es int ra- and ext rahepat ic biliary dilat at ion in a pat ient w it h a periampullary t umor. C, c ommon bile duc t ; G, gallbladder.

P.934 In pat ient s w it h know n or suspec t ed int rahepat ic neoplasm, delay ed imaging may be helpf ul t o dist inguish c holangioc arc inoma f rom ot her t umors, part ic ularly hepat oc ellular c arc inoma, bec ause of t he propensit y of t he f ormer t o show inc reased at t enuat ion on delay ed images (115,152). Loy er et al. (152) f ound t hat a delay t ime of 2 t o 6 minut es af t er injec t ion w as adequat e f or t his purpose, w hereas Keogan et al. (115) suggest ed a longer sc an delay of 10 t o 20 minut es. Bec ause pat ient s may f ind it dif f ic ult t o remain on t he CT t able f or longer periods of t ime, 10 minut es seems t o be a good c ompromise f or so- c alled quadruple phase imaging. As an alt ernat iv e t o t he “ negat iv e c ont rast ” images of t he biliary sy st em af f orded by t he prev iously not ed t ec hnique, some inv est igat ors hav e ev aluat ed oral or int rav enous c ont rast agent s t o opac if y t he gallbladder and bile duc t s prior t o CT . In a pilot st udy of 5 healt hy v olunt eers and 14 pat ient s w ho ingest ed 6 g of iopanoic ac id orally prior t o CT , t he examinat ion w as nondiagnost ic in 5 of t he pat ient s, limit ing it s ut ilit y (33). In anot her st udy , T akahashi et al. perf ormed CT c holangiography using iot roxic ac id, a new er

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2018

13 - The Biliary Tract int rav enous biliary c ont rast agent , in 133 pat ient s w it h suspec t ed panc reat ic or biliary disease (235). Pat ient s w ere sc anned 45 t o 75 minut es af t er t he agent w as c omplet ely inf used. T hese aut hors diagnosed c holedoc holit hiasis w it h a sensit iv it y of 89% and a spec if ic it y of 98% in a subset of 80 pat ient s w it h c onf irmed diagnoses and c onc luded t hat CT c holangiography is a reliable t ec hnique. How ev er, despit e t he low inc idenc e of c ont rast reac t ions in t his series (minor reac t ions w ere enc ount ered in only t hree pat ient s), t he hist oric ally high rat e of lif e- t hreat ening reac t ions w it h int rav enous

c holangiographic c ont rast agent s may limit t heir ac c ept anc e in t he near t erm. T he int rahepat ic bile duc t s bear a v ariable anat omic relat ionship t o t he hepat ic v essels and are t y pic ally v isualized as low at t enuat ion st ruc t ures adjac ent t o t he port al v enous branc hes (F ig. 13- 2). Dif f erent iat ion of normalc aliber f rom borderline dilat ed duc t s c an be dif f ic ult on noninv asiv e imaging; how ev er, t he normal bile duc t s measure 1.8 mm peripherally (range, 1 t o 3 mm), and 1.9 mm c ent rally (range, 1 t o 2.8 mm) (142). Normal- c aliber int rahepat ic duc t s are v isualized on CT in 40% of normal pat ient s. T he CHD and CBD, in c ont rast , are v isible in almost 100% of pat ient s w it h or w it hout biliary obst ruc t ion (F ig. 13- 3). T he maximal diamet er of t he normal CBD measures bet w een 6 and 7 mm (56). Some inv est igat ors hav e f ound only a minimal inc rease in duc t c aliber w it h adv anc ing age (191), w hereas ot hers hav e f ound an age- relat ed inc rease in pat ient s older t han age 75 y ears (108). T he c y st ic duc t is usually not seen on CT unless it is dilat ed. T he duc t w alls in t he biliary sy st em are t y pic ally paper- t hin and enhanc e slight ly . T he ef f ec t of c holec y st ec t omy on t he diamet er of t he ext rahepat ic bile duc t s has also been open t o debat e. One st udy of 234 pat ient s w ho w ere examined w it h ult rasound show ed only a small inc rease in duc t size post operat iv ely (mean diamet er 5.9 mm bef ore surgery v ersus 6.1 mm af t er c holec y st ec t omy ) (56). Puri et al. report ed no signif ic ant c hange in c ommon duc t diamet er in 34 pat ient s w ho w ere f ollow ed up t o 4 t o 6 mont hs af t er c holec y st ec t omy (197). How ev er, anot her st udy f ound signif ic ant dilat ion P.935 of t he CBD (mean 8.7 mm, range 4.1 t o 14.0 mm) in elderly pat ient s af t er c holec y st ec t omy (108).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2019

13 - The Biliary Tract

F igure 13- 2 Normal int rahepat ic duc t s. Cont rast - enhanc ed c omput ed t omography CT show s non- dilat ed c ent ral right int rahepat ic bile duc t s (ar r ow ) ant erior t o t he right port al v ein (ar r ow heads).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2020

13 - The Biliary Tract

F igure 13- 3 Normal c ommon bile duc t . Cont rast - enhanc ed c omput ed t omography show s normal c aliber c ommon duc t (ar r ow head) w it hin t he head of t he panc reas.

T he normal gallbladder is seen as a f luid- densit y st ruc t ure (F ig. 13- 4) in a f ossa t hat oc c upies t he same plane as t he int erlobar hepat ic f issure, and t he middle hepat ic v ein, w hic h is usually easily ident if ied on unenhanc ed and enhanc ed sc ans. Gallbladder at t enuat ion t y pic ally is similar t o t hat of w at er, but may be inc reased in pat ient s w it h sludge, c alc uli, milk- of - c alc ium, or hemat obilia (F ig. 13- 5). T he normal gallbladder w all measures bet w een 1 and 3 mm in t hic kness, and t y pic ally enhanc es. Anat omic v ariat ions suc h as t he Phry gian c ap (F ig. 13- 6), ment ioned prev iously , are readily v isualized w hen present , as are v ariat ions in gallbladder posit ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2021

13 - The Biliary Tract

F igure 13- 4 Normal gallbladder. Cont rast - enhanc ed c omput ed t omography demonst rat es a f luid- at t enuat ion gallbladder (G) w it h a t hin w all.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2022

13 - The Biliary Tract F igure 13- 5 Hemat obilia. Cont rast - enhanc ed c omput ed t omography image show s high- at t enuat ion c lot (C) in t he gallbladder.

F igure 13- 6 Phry gian c ap. Axial c omput ed t omography image of gallbladder f undus show s normal v ariant Phry gian c ap (ar r ow heads).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2023

13 - The Biliary Tract

F igure 13- 7 Pneumobilia and ref luxed oral c ont rast int o t he biliary duc t s. Cont rast - enhanc ed c omput ed t omography show s peripheral linear t rac t s of gas (ar r ow s) in t he expec t ed loc at ion of t he bile duc t s. T he peripheral loc at ion of t he gas is relat ed t o dense oral c ont rast (ar r ow heads) t hat has also ref luxed int o t he biliary t ree.

P.936 Air in t he bile duc t s, or pneumobilia, is c ommonly seen f ollow ing sphinc t erot omy , c reat ion of biliary - ent eric anast omoses, and plac ement of biliary st ent s. Demonst rat ion of pneumobilia in t his group of pat ient s indic at es a pat ent c ommunic at ion bet w een t he biliary t ree and t he gast roint est inal t rac t . Conv ersely , it s absenc e suggest s a lac k of c ommunic at ion (as disc ussed lat er). Oral c ont rast may also ref lux int o t he biliary sy st em (F ig. 13- 7).

MAGNETIC RESONANCE IMAGING: TECHNIQUE AND NORMAL APPEARANCES MRCP uses signal produc ed by f luid w it hin t he duc t s t hat c an c reat e images of t he biliary and panc reat ic duc t al sy st ems. Unlike ERCP and PT C st udies, how ev er, no ext rinsic c ont rast injec t ion is nec essary . T he MRCP t ec hniques

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2024

13 - The Biliary Tract t ake adv ant age of t he long spin- spin (T 2) relaxat ion t imes of t he st at ic bile and panc reat ic duc t f luid. T he long ec ho t ime allow s t he signal of most t issues, suc h as f at and solid organ signal, t o dec ay , and only c ert ain mat erials suc h as f luids w it h long T 2 relaxat ion t imes produc e signif ic ant signal. Earlier magnet ic resonanc e sequenc es suc h as gradient - rec alled ec ho and f ast spin ec ho prov ided MRCP images, but t hese long sequenc es of t en suf f ered f rom mot ion art if ac t and poor spat ial resolut ion. Images are now

c reat ed w it h one of sev eral magnet ic resonanc e sequenc es t hat use heav y T 2 w eight ing; single shot f ast - spin ec ho (SSF SE), half F ourier single- shot t urbo spin- ec ho (HAST E), and rapid- ac quisit ion relaxat ion- enhanc ed (RARE) imaging hav e been c ommonly desc ribed. T hese ult raf ast t ec hniques obt ain images rapidly and t heref ore reduc e art if ac t s c aused by pat ient mot ion and respirat ory mov ement , t hereby mit igat ing one of t he prev iously desc ribed disadv ant ages of MRI c ompared w it h CT . Proper pat ient preparat ion is c ruc ial t o opt imize imaging of t he biliary sy st em w it h MRCP. F or saf et y purposes, a c hec klist of exc lusion c rit eria suc h as aneury sm c lips or pac emakers should be disc ussed w it h t he pat ient bef ore t he proc edure. We rec ommend t hat t he pat ient f ast on t he day of t he proc edure w henev er possible t o reduc e bow el gas and perist alsis, but some c ent ers do not require f ast ing bef ore MRCP (251). A negat iv e oral c ont rast agent may be giv en prior t o t he examinat ion t o reduc e signal f rom t he duodenum adjac ent t o t he bile duc t s. T he pat ient remov es all ext ernal met al it ems prior t o ent ering t he magnet , and is giv en earplugs. Onc e in t he sc anning room, t he pat ient is inst ruc t ed t o lie supine and a phased- array t orso c oil is plac ed against t he c hest w all and upper abdomen. T he c oil ac t s as an ant enna t o improv e t he signal- t o- noise rat io of t he images. T he pat ient is c oac hed t o remain v ery st ill and t o pay spec ial at t ent ion t o t he breat hing inst ruc t ions t hat are giv en during t he st udy . Most of our MRCP st udies are perf ormed using a 1.5 T esla magnet . Mult iplanar t hin- slic e images show exc ellent spat ial resolut ion of t he duc t s. St ronger magnet ic f ields may prov ide bet t er spat ial resolut ion, but biliary MRI st udies may be sev erely limit ed on magnet s w it h f ield st rengt hs of less t han 1.0 T esla. A c ombinat ion of t hin- slic e and t hic k- slab sequenc es is perf ormed. Unlike CT , MRI images may be prospec t iv ely ac quired in any plane. Generally , w e use 1.6- t o 4- mm- t hic k c ont iguous slic es during a single breat hhold. Alt hough t he sourc e images are sensit iv e f or subt le det ails of t he bile duc t s, t he ent ire duc t c annot usually be display ed on a single slic e. How ev er,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2025

13 - The Biliary Tract a series of slic es may be “ st ac ked” t o f orm a maximum int ensit y projec t ion (MIP) image t hat simulat es t he images produc ed w it h ERCP. T he paramet ers f or MRCP are usually ec ho t ime 900 t o - 1,000, repet it ion t ime inf init e, 256 × 256 mat rix, and a f ield- of - v iew t hat is small but does not hav e signal w rap ov er t he biliary st ruc t ures. MRCP images may be obt ained w it hout int rav enous c ont rast , but it may be giv en f or T 1- axial imaging during t he examinat ion t o ev aluat e f or any panc reat ic lesion t hat may c ause biliary obst ruc t ion. T hic k- slab MRCP images may hav e less spat ial resolut ion t han t hin slic es, but

t hey c an also demonst rat e most of t he biliary sy st em in a single v iew (F ig. 138), simulat ing t he images obt ained by ERCP. T he slab t hic kness v aries bet w een 20 and 50 mm and may be limit ed by poor signal- t o- noise rat io if t he slab is t hin. Eac h slab requires only a c ouple of sec onds t o obt ain and is not of t en af f ec t ed by mot ion art if ac t . Of t en, mult iple planes of t hic k- slab imaging are obt ained, and are v aried at 15 degrees angulat ion inc rement s c ent ered on t he c ommon duc t . An addit ional t hic k slab is c hosen t o spec if ic ally image most of t he panc reat ic duc t . P.937 T he slab may be reposit ioned or t hinned t o exc lude signal f rom ov erly ing st ruc t ures, suc h as t he renal c ollec t ing sy st em. T he bow el may c ont ain f luid t hat w ill also show as high signal ov erly ing and likely obsc uring t he ext rahepat ic bile duc t s. T heref ore, as prev iously not ed, w e usually giv e a negat iv e oral c ont rast agent t o reduc e t he amount of ov erly ing signal f rom t he bow el (91), alt hough some aut hors do not use bow el c ont rast agent s rout inely (251).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2026

13 - The Biliary Tract

F igure 13- 8 Normal magnet ic resonanc e c holangiopanc reat ography . A: T hic kslab T 2- w eight ed images of t he biliary sy st em show s normal- c aliber smoot h c ommon duc t (ar r ow s) and smoot hly t apering int rahepat ic duc t s. T he panc reat ic duc t is w ell v isualized (ar r ow heads). B: Magnet ic resonanc e c holangiopanc reat ography of anot her pat ient w it h normal gallbladder, c ommon duc t , and panc reat ic duc t on oblique t hic k- slab image.

T here hav e been sev eral public at ions regarding t he use of MRCP in c onjunc t ion w it h int rav enous injec t ion of sec ret in t o ev aluat e biliary f unc t ion (159,160,165,166). Alt hough t he supply of sec ret in has been limit ed at t imes, it is c urrent ly av ailable f or f unc t ional ev aluat ion of t he biliary sy st em. Sec ret in (1 mL/kg) st imulat es sec ret ion by t he panc reas, w hic h allow s bet t er dist ension of t he panc reat ic duc t (159,165,166). T he ef f ec t is rapid and resolv es quic kly . Repeat ed imaging w it h t hic k- slab MRCP ev ery 15 t o 30 sec onds f or 10 t o 15 minut es is perf ormed. T his allow s dy namic ev aluat ion of t he panc reat ic duc t and ampullary regions. Sec ret in st imulat ion allow s improv ed v isualizat ion of t he panc reat ic duc t as c ompared w it h st andard MRCP (159). T his t ec hnique also has been report ed t o improv e t he det ec t ion of panc reas div isum (165).

Limitations of Magnetic Resonance Cholangiopancreatography Small or impac t ed biliary duc t al c alc uli may be missed on MRCP (196). Air or met al art if ac t s may limit v isualizat ion of t he ent ire duc t . Anot her limit at ion of MRCP oc c urs w hen rec onst ruc t ed images miss small duc t al st ones as a result of v olume av eraging of signal (12). Volume av eraging c an espec ially mask small st ones in t he t hic k- slab HAST E images, and t he t hin- slic e MRCP sourc e images should alw ay s be rev iew ed f or f illing def ec t s (101). Art if ac t s are c ommonly enc ount ered in MRCP examinat ions. T hese are of t en f rom gas, c lot , met allic c lips, mot ion art if ac t , or pulsat ion art if ac t (123,203,228,258). Respirat ory mot ion may art if ac t ually simulat e duc t al st ones or st ric t ures (101). T his oc c urs bec ause of misregist rat ion of dat a during breat hing mot ion in a pat ient w ho is unable t o adequat ely breat h- hold (101). Pulsat ilit y art if ac t f rom t he hepat ic art ery may simulat e st ric t ure in t he c ommon duc t . T he CHD and lef t hepat ic duc t are most c ommonly inv olv ed (101). T he lef t hepat ic duc t may be c ompressed by t he right hepat ic art ery

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2027

13 - The Biliary Tract (101). T he mid CBD may be narrow ed ext rinsic ally by t he gast roduodenal art ery (101). In t he absenc e of ot her art if ac t s, MRCP may st ill ov erest imat e

t he sev erit y of a biliary st enosis on maximum int ensit y projec t ion images. T his c an be ov erc ome using t hic k- slab HAST E images t o doc ument t he absenc e of a st ric t ure in a region of quest ion (101). In t he absenc e of sec ret in st imulat ion, a normal c ollapsed panc reat ic duc t c an simulat e a panc reat ic duc t st ric t ure. In some pat ient s, t he examinat ion c annot be perf ormed bec ause t he pat ient has a pac emaker or c erebral aneury sm c lips or suf f ers f rom c laust rophobia. F urt hermore, f alse- negat iv e result s of MRCP may oc c ur if t he lev el of P.938 obst ruc t ion is at t he ampulla (247). RARE images may not v isualize duc t s t hat c ont ain blood produc t s. How ev er, t his w eakness may oc c asionally be of benef it by show ing t hat a signal f rom a v asc ular st ruc t ure is not an abnormal biliary radic al, bec ause blood v essels are not v isible on RARE imaging (90). An inadequat e MRCP may result f rom inappropriat e selec t ion of t he region of imaging f or t hin- or t hic k- slab MRCP. Coronal oblique images are loc alized on axial images t hrough t he liv er. It is possible t hat t he CBD may be post erior t o t he lev els selec t ed at t he lev el of t he int rahepat ic duc t s. If t he slic es are not selec t ed t o inc lude t he ent ire duc t , int erpret at iv e errors may oc c ur (63). T his int erpret iv e error c an be av oided by rev iew of t he t hin- slic e sourc e images. If a negat iv e oral c ont rast agent is not used, f luid in t he duodenum may obsc ure t he c ommon duc t . Ot her st ruc t ures suc h as t he st omac h or uret er may simulat e an abnormalit y on MRCP. Proper selec t ion of t he slic e loc at ion may be used t o exc lude ov erly ing bow el signal, but it may be dif f ic ult t o c omplet ely remov e high signal bow el f luid t hat is adjac ent t o biliary st ruc t ures. St andard MRCP has limit at ions inv olv ing v isualizat ion and int erpret at ion of t he ampullary region (75,79,167). Bec ause ERCP c an direc t ly v isualize t he ampulla, it should be perf ormed if t here is c linic al c onc ern f or an ampullary lesion, ev en if no lesion is seen in t his region on MRCP. F urt hermore, MRCP c annot prov ide t herapy and may not be as usef ul in pat ient s w it h a v ery high likelihood of duc t al st ones t hat w ould require remov al.

CONGENITAL ABNORMALITIES AND DISEASES OF THE GALLBLADDER

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2028

13 - The Biliary Tract Congenital Abnormalities of the Gallbladder As not ed prev iously , c ongenit al v ariat ions of gallbladder anat omy , inc luding int rahepat ic gallbladder and gallbladder duplic at ion, are usually easily rec ognized on CT , MRI, or ult rasonography . Gallbladder f olds and sept at ions are also readily apparent , part ic ularly on ult rasonography , bec ause of it s abilit y t o image t hem in oblique planes. It is espec ially import ant t o def init iv ely ident if y t he gallbladder w hen it is loc at ed in an at y pic al posit ion.

Oc c asionally , a long mesent ery may permit t he gallbladder t o herniat e t hrough t he f oramen of Winslow int o t he lesser sac and undergo t orsion and st rangulat ion (16). If t here is doubt w het her a f luid- f illed st ruc t ure in t he upper abdomen represent s t he gallbladder, radionuc lide biliary imaging is usually def init iv e, unless t he c y st ic duc t is obst ruc t ed.

Diseases of the Gallbladder Cholelithiasis and Sludge St ones t hat dev elop in t he gallbladder, in dist inc t ion t o t hose t hat f orm w it hin t he biliary t ree, are exc eedingly c ommon. It is est imat ed t hat 20 t o 25 million adult s in t he Unit ed St at es hav e c holelit hiasis, alt hough t he ac t ual prev alenc e is unknow n, bec ause most are asy mpt omat ic (26,109). Women are af f ec t ed more f requent ly t han men, and gallst ones are more c ommon w it h adv anc ing age. Approximat ely 70% t o 80% of gallbladder st ones are of t he c holest erol v ariet y , w it h pigment , mixed, and c alc ium c arbonat e c alc uli c omprising t he remainder. Of t hese, c alc ium c arbonat e st ones are t he least c ommon. T he pat hogenesis of c holelit hiasis is t hought t o be relat ed t o hy persat urat ion of bile w it h v arious c onst it uent s, and is assoc iat ed w it h diminished gallbladder empt y ing and an inc reased int est inal t ransit t ime. T he risk of c holest erol st ones is inc reased by v arious c linic al f ac t ors, inc luding elev at ed est rogen lev els (due t o pregnanc y , oral c ont rac ept iv es, or post menopausal hormone replac ement t herapy ), obesit y , rapid w eight loss, hy perlipidemia, int est inal hy pomot ilit y , genet ic s, longst anding parent eral nut rit ion, c ert ain drugs (e.g., oc t reot ide, c ef t riaxone), spinal c ord injuries, and diseases of t he t erminal ileum (109). Biliary sludge is a sediment c onsist ing of v arious subst anc es, inc luding c holest erol c ry st als, w hic h hav e prec ipit at ed f rom bile, and is assoc iat ed w it h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2029

13 - The Biliary Tract many of t he same c linic al f ac t ors as c holelit hiasis (216). Alt hough sludge is usually asy mpt omat ic and of t en resolv es spont aneously , it may c ause biliary obst ruc t ion in t he absenc e of c holelit hiasis or it may be a prec ursor of biliary st ones.

As not ed prev iously , most pat ient s w it h c holelit hiasis are asy mpt omat ic (109). Alt hough pat ient s w it h gallst ones f requent ly report indigest ion, int oleranc e t o f at t y f oods, and belc hing, t hese sy mpt oms are nonspec if ic . How ev er, w hen gallst ones migrat e int o and obst ruc t t he gallbladder nec k or t he c y st ic duc t , sy mpt oms may ensue. Pat ient s w it h t ransient duc t al obst ruc t ion experienc e biliary c olic , w hic h is c lassic ally loc alized t o t he right upper quadrant , w axes and w anes ov er t he c ourse of 1 t o 3 hours, and may be assoc iat ed w it h nausea and v omit ing (26,109). How ev er, if obst ruc t ion persist s, inf lammat ion of t he gallbladder w all (ac ut e c holec y st it is) may dev elop (as disc ussed lat er in t his c hapt er).

Imaging of Cholelithiasis and Sludge Approximat ely 80% t o 85% of gallst ones are inv isible on c onv ent ional radiographs bec ause t hey do not c ont ain suf f ic ient c alc ium (243). F or many y ears, oral c holec y st ography w as t he proc edure of c hoic e t o diagnose c holelit hiasis, but has been largely replac ed by c ross sec t ional imaging in rec ent dec ades. In most pat ient s, sonography is t he best init ial imaging t est in a pat ient w it h suspec t ed gallbladder c alc uli, bec ause of it s high ac c urac y , relat iv ely low c ost , it s lac k of ionizing radiat ion, it s abilit y t o ev aluat e t he liv er and bile duc t s, and it s av ailabilit y at t he bedside (26). Gallbladder c alc uli appear on ult rasound as ec hogenic int raluminal st ruc t ures w hic h are assoc iat ed w it h post erior ac oust ic shadow s (F ig. 13- 9); mobilit y is anot her dist inguishing f eat ure in a pat ient w ho c an be examined in t he lef t lat eral dec ubit us, prone, or upright posit ion. T he presenc e of ac oust ic P.939 shadow ing and mobilit y serv es t o dist inguish st ones f rom gallbladder poly ps and f oc al aggregat es of sludge, so- c alled t umef ac t iv e sludge (F ig. 13- 10). Nont umef ac t iv e sludge is usually readily ident if ied as lay ering, dependent mat erial t hat is more ec hogenic t han bile (F ig. 13- 11).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2030

13 - The Biliary Tract

F igure 13- 9 Cholelit hiasis. Gray sc ale ult rasound show s round mobile ec hogenic st ruc t ures (ar r ow ) w it h shadow ing (ar r ow ) in t he gallbladder lumen. T here is no w all t hic kening or peric holec y st ic f luid.

Computed Tomography and Magnetic Resonance Imaging of Cholelithiasis. Alt hough t he sonographic diagnosis of c holelit hiasis is usually st raight f orw ard, pat ient s w ho are large or unc ooperat iv e may prov e c hallenging, and CT may be helpf ul. T he densit y of gallst ones on CT v aries f rom heav ily c alc if ied t o hy podense, w it h t he lat t er appearanc e c harac t erist ic of pure c holest erol st ones (F ig. 13- 12) (18). Large or medium- size c alc uli are usually easily rec ognized (F ig. 13- 13), but minut e st ones may be easily ov erlooked.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2031

13 - The Biliary Tract

F igure 13- 10 T umef ac t iv e sludge. Gray sc ale ult rasound of t he gallbladder show s a round ec hogenic st ruc t ure (ar r ow ) w it hout shadow ing. On f urt her imaging, t he debris c hanged c onf igurat ion and lay ered dependent ly .

F igure 13- 11 Lay ering sludge. Gray sc ale ult rasound of t he gallbladder show s smoot hly lay ering ec hogenic mat erial (ar r ow s) w it hin an ot herw ise normal gallbladder.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2032

13 - The Biliary Tract As w it h ult rasonography , t he diagnosis of c holelit hiasis on CT c an be

c hallenging w hen t he gallbladder is markedly c ont rac t ed and t heref ore dif f ic ult t o dist inguish f rom adjac ent opac if ied duodenum or ot her bow el. Sludge and minut e c alc uli (so- c alled biliary sand) t y pic ally appear as a P.940 lay er of dependent high at t enuat ion w it hin t he gallbladder lumen, and c annot be reliably dist inguished by CT . As w ell, dependent densit y mimic king sludge may be seen in pat ient s w it h so- c alled v ic arious exc ret ion of w at er- soluble c ont rast media by t he gallbladder (F ig. 13- 14). Gallbladder exc ret ion of int rav enously - administ ered c ont rast is of t en not c linic ally signif ic ant , and is seen in pat ient s w it h and w it hout uret eral obst ruc t ion (51,95).

F igure 13- 12 Subt le gallst ones on c omput ed t omography . Nonc ont rast c omput ed t omography CT at t he lev el of t he gallbladder show s mild het erogeneit y (arrow heads) w it hout w ell- def ined gallst ones. Gallst ones w ere c learly v isible on subsequent gray sc ale ult rasound of t he gallbladder (not show n).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2033

13 - The Biliary Tract

F igure 13- 13 Cholelit hiasis. Cont rast - enhanc ed c omput ed t omography show s mult iple, c alc if ied gallst ones.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2034

13 - The Biliary Tract

F igure 13- 14 Cont rast exc ret ion by gallbladder. Dense c ont rast opac if ies t he gallbladder (ar r ow s) w it h a small amount of lay ering of densit y in a pat ient w ho had anot her st udy using int rav enous c ont rast prior t o t his c omput ed t omography .

T he sensit iv it y of MRCP f or det ec t ing gallst ones is as high as 98% (31,202). Cholelit hiasis usually appears as mult iple dependent round st ruc t ures w it hin t he high T 2 signal bile of t he gallbladder (F ig. 13- 15). T he st ones usually hav e low T 1 and low T 2 signal c harac t erist ic s. If t here is w at er mat rix w it hin t he st one, t he signal may be v ariable (113).

Cholecystitis Obst ruc t ion of t he gallbladder by a st one in t he gallbladder nec k or c y st ic duc t c auses dist ension, inc reased int rac holec y st ic pressure, mural isc hemia, bac t erial inv asion, and ac ut e inf lammat ion. A minorit y of pat ient s w it h ac ut e c holec y st it is hav e no ev idenc e of st ones. T he pat hogenesis of ac alc ulous c holec y st it is is not w ell underst ood, but is t hought t o be relat ed t o isc hemia, biliary st asis, and inf lammat ion. Clinic ally , pat ient s t y pic ally present w it h ac ut e right upper quadrant pain t hat of t en radiat es t o t he right shoulder or bac k. Pronounc ed t enderness ov er t he gallbladder (Murphy 's sign) may also be seen. If lef t unt reat ed, empy ema of t he gallbladder may ensue, or t he gallbladder w all may bec ome nec rot ic and perf orat e, leading t o a loc alized absc ess or perit onit is. In some pat ient s, repeat ed episodes of ac ut e inf lammat ion lead t o c hronic c holec y st it is, w hic h is c harac t erized by t hic kening, inf ilt rat ion, and f ibrosis of t he gallbladder w all.

Imaging of Cholecystitis As in pat ient s w it h suspec t ed c holelit hiasis, ult rasound is t he proc edure of c hoic e, w it h a report ed sensit iv it y and spec if ic it y of great er t han 95% (200). Sonographic signs inc lude t hic kening of t he gallbladder w all great er t han 3 mm, peric holec y st ic f luid, and t enderness ov er t he gallbladder, t he so- c alled sonographic Murphy 's sign (F ig. 13- 16). Radionuc lide c holesc int igraphy is also highly sensit iv e f or t he diagnosis of ac ut e c alc ulous c holec y st it is by demonst rat ing nonv isualizat ion of t he obst ruc t ed gallbladder, but is most usef ul as an adjunc t iv e t est in pat ient s w it h indet erminat e sonograms. Alt hough not t he f irst - line imaging modalit y in pat ient s w it h suspec t ed unc omplic at ed ac ut e c holec y st it is, CT is nonet heless helpf ul in equiv oc al c ases or in pat ient s w ho are sc anned f or nonspec if ic abdominal pain. Some of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2035

13 - The Biliary Tract t he CT f indings in ac ut e c holec y st it is, namely gallst ones, mural t hic kening (F ig. 13- 17), and peric holec y st ic f luid, parallel t he f eat ures seen

sonographic ally . How ev er, CT is muc h bet t er t han ult rasound at demonst rat ing assoc iat ed inf lammat ory c hanges, w hic h appear as st randing or inf ilt rat ion of peric holec y st ic t issues (F ig. 13- 18). CT may also show hy peremia of t he adjac ent inf lamed liv er f ollow ing administ rat ion of int rav enous c ont rast medium, making it possible t o dist inguish inf lammat ory f rom noninf lammat ory gallbladder w all t hic kening (262). In t he set t ing of ac ut e t rauma, gallbladder injury may mimic t he f indings of ac ut e c holec y st it is at CT (F ig. 13- 19). In pat ient s w it h emphy semat ous c holec y st it is, w hic h is most f requent in diabet ic pat ient s, CT c an demonst rat e int ramural gas (F ig. 13- 20).

F igure 13- 15 Magnet ic resonanc e imaging. MRI of c holelit hiasis. A: T 2w eight ed magnet ic resonanc e imaging of t he gallbladder show s mult iple round signal v oids w it hin t he normal high T 2- w eight ed signal bile in t he gallbladder. B: T hic k- slab magnet ic resonanc e c holangiopanc reat ography MRCP show s t he st ones (ar r ow s) in t he gallbladder f undus.

P.941 CT has also been report ed t o be helpf ul in pat ient s w it h xant hogranulomat ous c holec y st it is, an unusual c ondit ion t hat is most c ommon in older w omen (189). Alt hough some of t he CT f indings are similar t o t hose in t he more c ommon f orms of ac ut e c holec y st it is, a hy podense band w as seen in t he gallbladder w all in 33% of t he 26 pat ient s st udied. In t his series, it w as suggest ed t hat pat ient s w it h xant hogranulomat ous c holec y st it is may experienc e an inc reased inc idenc e of problems at laparosc opic c holec y st ec t omy . More import ant ,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2036

13 - The Biliary Tract

how ev er, is t he pot ent ial f or xant hogranulomat ous c holec y st it is t o mimic or be assoc iat ed w it h gallbladder c arc inoma (125,134).

F igure 13- 16 Cholec y st it is. Sonogram of right upper quadrant show s gallbladder w all t hic kening (ar r ow heads), sludge (S), and st ones (ar r ow s).

CT is also v aluable t o assess adjac ent organs and t o diagnose c omplic at ions of ac ut e c holec y st it is. In pat ient s w it h P.942 ac ut e onset of right - sided abdominal pain, f or example, CT may demonst rat e ac ut e panc reat it is or py elonephrit is, w it h c an c ause similar signs and sy mpt oms. As w ell, c omplic at ions suc h as gallbladder perf orat ion w it h f ormat ion of a loc alized, peric holec y st ic absc ess or perit onit is are depic t ed f ar bet t er w it h CT t han sonography . CT is also exc ellent f or diagnosing small bow el obst ruc t ion in pat ient s in w hom a gallst one has gained ac c ess t o t he gast roint est inal t rac t v ia gallbladder perf orat ion, t ermed gallst one ileus. Obst ruc t ion at t he lev el of t he duodenum is know n as Bouv er et 's sy ndr om e (F ig. 13- 21) (192).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2037

13 - The Biliary Tract

F igure 13- 17 Ac ut e c holec y st it is. Cont rast - enhanc ed c omput ed t omography CT show s gallbladder w all t hic kening w it h bright muc osal enhanc ement (ar r ow s) and w all t hic kening (ar r ow heads). Ac ut e c holec y st it is w as c onf irmed at surgery .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2038

13 - The Biliary Tract

F igure 13- 18 Sev ere ac ut e c holec y st it is. Cont rast - enhanc ed c omput ed t omography demonst rat es dif f use gallbladder irregular w all t hic kening and peric holec y st ic inf ilt rat ion (ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2039

13 - The Biliary Tract

F igure 13- 19 Gallbladder av ulsion. Cont rast - enhanc ed c omput ed t omography in a pat ient being ev aluat ed f or t rauma show s disrupt ed, non- enhanc ing ant erior w all of t he gallbladder (ar r ow heads) w it h peric holec y st ic f luid (F ).

F igure 13- 20 Emphy semat ous c holec y st it is. Cont rast - enhanc ed c omput ed t omography w it h A: sof t t issue w indow s show s gas- densit y f illing t he gallbladder (G). Perihepat ic absc ess w it h f luid and gas is also present (ar r ow heads). B: Image of t he same lev el using lung w indow s bet t er delineat es t he gas bubbles in t he gallbladder and gallbladder w all (ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2040

13 - The Biliary Tract

F igure 13- 21 Bouv eret 's sy ndrome. Nonc ont rast c omput ed t omography at t he lev el of t he gallbladder and duodenum show s a large f illing def ec t w it hin t he sec ond port ion of t he duodenum. T he low - densit y ov al st one (ar r ow s) is out lined by dense c ont rast w it hin t he bow el. Gas w as present w it hin t he gallbladder (not show n).

P.943

Magnetic Resonance Imaging of Acute Cholecystitis. MRCP is v ery sensit iv e (91%) and show s good spec if ic it y (79%) and ac c urac y (89%) f or ac ut e c holec y st it is (202). T he MRI f indings inc lude gallbladder w all t hic kening and inc reased w all enhanc ement on T 1- w eight ed images (151). T here may be high T 2 signal f luid around t he gallbladder (F ig. 13- 22). Gallbladder dilat at ion and gallst ones are also assoc iat ed f indings. MRCP may det ec t t he obst ruc t ing st one in t he gallbladder nec k or c ommon duc t t o prov ide t he et iology of t he inf lammat ion (188). On c ont rast - enhanc ed MRI, t here may be abnormal enhanc ement of t he liv er parenc hy ma adjac ent t o t he inf lamed gallbladder due t o hy peremia, a f inding t hat has also been desc ribed on CT (151,262).

Gallbladder Polyps

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2041

13 - The Biliary Tract Adenomat ous and hy perplast ic poly ps are c ommon inc ident al f indings at

gallbladder sonography , and also may be seen at t hin- sec t ion CT (F ig. 13- 23). Most gallbladder poly ps are of no c linic al signif ic anc e, alt hough it is dif f ic ult t o absolut ely exc lude t he rare possibilit y of v ery early gallbladder malignanc y in a giv en pat ient . At present , t he only imaging f eat ure t hat c an be used t o dist inguish innoc uous lesions f rom t hose t hat should be f ollow ed or surgic ally remov ed is size (176). Poly ps larger t han 10 mm should be v iew ed w it h suspic ion, w hereas lesions t hat are 5 mm or smaller c an be saf ely ignored. Poly ps of int ermediat e size c an be f ollow ed sonographic ally f or signs of grow t h, alt hough t heir c linic al signif ic anc e is doubt f ul in t he majorit y of pat ient s. Not ably , how ev er, it appears t hat pat ient s w it h primary sc lerosing c holangit is (PSC) and poly ps hav e an inc reased risk of gallbladder malignanc y , suggest ing t hat eit her c holec y st ec t omy or c lose imaging surv eillanc e is w arrant ed (28).

Porcelain Gallbladder T he desc ript iv e t erm por c elain gallbladder ref ers t o c alc if ic at ion in t he gallbladder w all, w hic h usually is assoc iat ed w it h c hronic inf lammat ion. Calc if ic at ion may be part ial or c omplet e, and is easily rec ognized on CT (F ig. 13- 24). At sonography , porc elain gallbladder must be dist inguished f rom a c ont rac t ed gallbladder c ont aining a single, large c alc ulus, in w hic h t he gallbladder w all is usually seen t o be separat e f rom t he subadjac ent st one (F ig. 13- 25). If c alc if ic at ion is suf f ic ient ly dense, ac oust ic shadow ing may prec lude v isualizat ion of t he gallbladder lumen on sonography , and CT may be helpf ul t o exc lude c holelit hiasis. On MRI, c alc if ic at ion in t he w all may appear as low T 1 and low T 2 signal.

Adenomyomatosis Adenomy omat osis is a c ondit ion t hat is c harac t erized by t hic kening of t he musc ularis of t he gallbladder w all along w it h prolif erat ion of t he muc osa. Ev ent ually , t he ov ergrow n muc osa prot rudes t hrough t he t hic kened musc ular lay er t o f orm so- c alled Rokit ansky - Asc hof f sinuses; if suf f ic ient ly large, t hey may be v isible on sonography . T hree v ariant s of adenomy omat osis hav e been desc ribed: f undal, segment al, and dif f use (99). T he f undal t y pe, w hic h is t he most c ommon, manif est s as a disc ret e mass in t he P.944

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2042

13 - The Biliary Tract

gallbladder f undus; t he ot her t w o t y pes of adenomy omat osis are c harac t erized by a segment al st ric t ure and by generalized t hic kening of t he gallbladder w all, respec t iv ely .

F igure 13- 22 Ac ut e c holec y st it is. Non- enhanc ed T 2- w eight ed MRI of t he gallbladder show s gallbladder w all t hic kening and hy perint ense T 2 signal f luid (ar r ow s) surrounding t he gallbladder (G).

F igure 13- 23 Small gallbladder poly p. A: Cont rast - enhanc ed c omput ed t omography of t he gallbladder show s a small, nondependent st ruc t ure

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2043

13 - The Biliary Tract (ar r ow head) arising f rom t he gallbladder w all, projec t ing int o lumen. B: Gray sc ale ult rasound of t he gallbladder in t he same pat ient c onf irms a small, nondependent , nonshadow ing poly p (ar r ow head).

Not surprisingly , t he CT appearanc e of adenomy omat osis is nonspec if ic , unless t he indiv idual Rokit ansky - Asc hof f sinuses c an be ident if ied (99). Dif f erent iat ing t he f undal v ariant f rom gallbladder c arc inoma or t he dif f use f orm f rom c hronic c holec y st it is may be problemat ic . Sonography may be of benef it by demonst rat ing ec hogenic f oc i w it h so- c alled c omet - t ail art if ac t s w it hin t he mural sinuses (F ig. 13- 26). T he c linic al signif ic anc e of adenomy omat osis has been t he subjec t of some debat e; most aut horit ies c onsider it t o be an asy mpt omat ic c ondit ion t hat is not assoc iat ed w it h eit her c holelit hiasis or gallbladder malignanc y , alt hough t here hav e been sc at t ered report s of sy mpt omat ic c ases (215).

F igure 13- 24 Porc elain gallbladder. A: Cont rast - enhanc ed c omput ed t omography (CT ) show s ext ensiv e c alc if ic at ion in t he w all of a c ont rac t ed gallbladder. When it is t his dif f use, t he w all c alc if ic at ion may be dif f ic ult t o dif f erent iat e f rom c holelit hiasis. B: CT image of anot her pat ient demonst rat es disc ont inuous mural c alc if ic at ion.

Gallbladder Carcinoma Carc inoma of t he gallbladder is t he sixt h most c ommon gast roint est inal malignanc y in t he Unit ed St at es (140). It is primarily a disease of t he elderly , w it h a mean age at present at ion of 72 y ears, and has a 3:1 f emale predominanc e. Cert ain et hnic groups, inc luding Nat iv e and Hispanic Americ ans, are at inc reased risk, possibly bec ause of t heir higher prev alenc e of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2044

13 - The Biliary Tract gallbladder c alc uli. Cholelit hiasis is a w ell- doc ument ed risk f ac t or f or

gallbladder c arc inoma, presumably bec ause c alc uli lead t o c hronic inf lammat ion and dy splasia. Porc elain gallbladder is also assoc iat ed w it h P.945 gallbladder c arc inoma, alt hough t he assoc iat ion may not be as st rong as prev iously t hought (231). Int erest ingly , t he dif f use f orm of mural c alc if ic at ion may not be assoc iat ed w it h an inc reased risk of gallbladder malignanc y (231).

F igure 13- 25 Wall- ec ho- c omplex sign. Gray sc ale ult rasound of t he gallbladder show s a t hin ec hogenic gallbladder w all (ar r ow s) w it h a t hin hy poec hoic c resc ent of bile ant erior t o an ec hogenic , shadow ing gallst one (ar r ow heads).

Ot her c ondit ions t hat are assoc iat ed w it h an inc reased inc idenc e of gallbladder c arc inoma inc lude c ongenit al anomalies of t he bile duc t s (c holedoc hal c y st , c ongenit al c y st ic dilat at ion of t he biliary t ree, anomalous panc reat ic obiliary junc t ion, and low c y st ic duc t insert ion), and PSC. Early gallbladder c arc inoma is usually c linic ally oc c ult ; t heref ore, pat ient s most of t en hav e loc ally adv anc ed or met ast at ic disease at present at ion. T he 5- y ear surv iv al rat e is poor (47,237). Sy mpt oms inc lude w eight loss and abdominal pain, and pat ient s may hav e a palpable mass in t he right upper quadrant or jaundic e if t here is assoc iat ed biliary obst ruc t ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2045

13 - The Biliary Tract

F igure 13- 26 Adenomy omat osis. Gray sc ale ult rasound of t he gallbladder demonst rat es ec hogenic “ c omet t ail” art if ac t s (ar r ow s) arising f rom t he w all and projec t ing int o t he gallbladder lumen.

Pat hologic ally , most gallbladder malignanc ies are adenoc arc inomas, w hic h arise f rom t he muc osal lay er, and range f rom poorly t o w ell dif f erent iat ed. Ot her primary malignanc ies of t he gallbladder, suc h as sarc omas, ly mphomas, and c arc inoid t umors, are muc h less c ommon, as are met ast ases t o t he gallbladder (most c ommonly f rom melanoma) (230). T he majorit y (68%) of gallbladder c arc inomas are inf ilt rat ing, w hereas t he remaining 32% are poly poid (223). Most arise in t he gallbladder f undus, in w hic h c ase t hey may be c onf used w it h t he f undal v ariant of adenomy omat osis.

Computed Tomography of Gallbladder Carcinoma T he CT appearanc e ref lec t s t he gross present at ion of t he disease, w hic h t akes t he f orm of a mass t hat c omplet ely replac es t he gallbladder, f oc al or dif f use mural t hic kening, or an int raluminal mass, w hic h is least c ommon (F ig. 13- 27). T he mass- f orming v ariant s t y pic ally enhanc e t o a v ary ing degree, depending on t he ext ent of t umor nec rosis. Direc t inv asion int o t he c ont iguous hepat ic parenc hy ma may be ev ident . CT also may be helpf ul t o show inv olv ement of t he hepat ic f lexure of t he c olon or regional adenopat hy . In pat ient s in w hom t he primary t umor has grow n along t he bile duc t s, biliary

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2046

13 - The Biliary Tract

obst ruc t ion may be present . Hemat ogenous met ast ases are also w ell depic t ed by CT (F ig. 13- 28). Hist oric ally , t he f orm of gallbladder c arc inoma t hat produc es f oc al or generalized w all t hic kening has been t he most dif f ic ult t o diagnose, as it has a similar appearanc e t o c hronic c holec y st it is. It is t heref ore part ic ularly import ant t o look f or signs of loc al or met ast at ic inv olv ement in suc h P.946 c ases. How ev er, a rec ent report suggest s t hat mural enhanc ement pat t erns may help t o dist inguish t hese t w o c ondit ions. In a st udy of 82 pat ient s, Y un et al. f ound t hat gallbladder c arc inoma w as c harac t erized by art erial phase enhanc ement of a t hic kened inner w all, w hic h remained hy perat t enuat ing or bec ame isodense t o t he liv er parenc hy ma during t he v enous phase (268). Chronic c holec y st it is, in c ont rast , show ed a t hin, isoat t enuat ing inner w all during bot h phases. Met ast ases t o t he gallbladder may also present as mural masses, and c annot be reliably dist inguished f rom t he f oc al f orm of gallbladder c arc inoma based on t heir CT appearanc e alone (F ig. 13- 29).

F igure 13- 27 Loc alized gallbladder c arc inoma. Cont rast - enhanc ed c omput ed t omography show s a het erogeneous, lobulat ed mass (ar r ow s) projec t ing int o t he lumen of t he gallbladder f undus.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2047

13 - The Biliary Tract

F igure 13- 28 Gallbladder c arc inoma. Axial c omput ed t omography image show s mult iple hepat ic met ast ases (M). A disc ret e gallbladder mass also is seen (ar r ow ).

Magnetic Resonance Imaging of Gallbladder Carcinoma T he MR appearanc e mirrors t he appearanc e at CT . F indings inc lude f oc al or dif f use t hic kening of t he gallbladder w all. T he mass usually w ill enhanc e rapidly and ret ain c ont rast . T he appearanc e must be dif f erent iat ed f rom benign gallbladder w all t hic kening due t o inf lammat ion or benign poly ps, w hic h are more unif orm and do not ret ain c ont rast (266).

CONGENITAL ABNORMALITIES AND DISEASES OF THE BILE DUCTS Choledochal Cysts and Choledochoceles

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2048

13 - The Biliary Tract

Choledoc hal c y st s are c harac t erized by c y st ic dilat at ion of t he int rahepat ic or ext rahepat ic bile duc t s. A c lassif ic at ion sc heme w as init ially proposed by Alonso- Lej et al. (10), and w as subsequent ly modif ied by T odani et al. (241) t o inc lude f iv e t y pes. T y pe I c y st s c onsist of c y st ic (IA), f oc al segment al (IB), and f usif orm (IC) dilat at ion of t he c ommon duc t . T y pe II c y st s are t rue div ert ic ula of t he CBD. T y pe III c holedoc hal c y st s, also know n as c holedoc hoc eles, represent c y st ic herniat ion of t he dist al CBD int o t he duodenum. T y pe IV c y st s inc lude mult iple int ra- and ext rahepat ic c y st s (IVA) and mult iple ext rahepat ic c y st s (IVB). F inally , T y pe V c holedoc hal c y st s c omprise mult iple c y st ic dilat at ions of t he int rahepat ic bile duc t s, also know n as Car oli disease (disc ussed lat er in t his c hapt er). T he t rue inc idenc e of c holedoc hal c y st s is not know n; how ev er, t hey oc c ur in approximat ely 1 in 15,000 liv e birt hs in West ern c ount ries (213). As t his suggest s, c holedoc hal c y st s are t hought t o be c ongenit al anomalies, alt hough some may be ac quired (81). Moreov er, Babbit t has proposed a c ausat iv e assoc iat ion w it h anomalies of t he junc t ion bet w een t he c ommon bile and panc reat ic duc t s, w hic h permit s ref lux of panc reat ic enzy mes int o t he c ommon duc t , leading t o w eakening and progressiv e dilat at ion (15). Choledoc hal c y st s are t y pic ally diagnosed in c hildhood, and may present w it h jaundic e, abdominal pain, or v omit ing. T hey are also assoc iat ed w it h a range of c omplic at ions, inc luding biliary lit hiasis, and, most import ant ly , malignanc y of t he biliary t rac t or panc reas (57). Depending on t he t y pe of c holedoc hal c y st , t reat ment by surgic al exc ision of t he c y st or endosc opic sphinc t erot omy has been adv oc at ed t o prev ent c omplic at ions (57,130). At CT or MRI, c holedoc hal c y st s appear as f luid- f illed st ruc t ures, w hic h are in c ont inuit y w it h t he bile duc t s (204) (F ig. 13- 30). T he presenc e of luminal nodularit y or enhanc ement is suggest iv e of c holangioc arc inoma, and should prompt f urt her inv est igat ion w it h ERCP. CT has also been show n t o be c apable of demonst rat ing an anomalous panc reat ic obiliary junc t ion in a pat ient w it h a c holedoc hal c y st , and may be helpf ul f or preoperat iv e assessment (234). Choledoc hoc eles are rare, c omprising less t han 2% of c y st ic anomalies of t he bile duc t s (46,74). Alt hough t hey are inc luded in t he T odani c lassif ic at ion desc ribed prev iously , t he assoc iat ion has been c alled int o quest ion by some researc hers (199). Clinic al manif est at ions inc lude abdominal pain panc reat it is, nausea or v omit ing, and jaundic e (164). Cross- sec t ional imaging demonst rat es a f luid- f illed sac w hic h prot rudes int o t he duodenal lumen, but does not

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2049

13 - The Biliary Tract opac if y w it h oral c ont rast (74). Management opt ions range f rom endosc opic t reat ment t o surgic al resec t ion.

Caroli Disease Caroli disease, also know n as c om m unic at ing c av er nous ec t asia of t he int r ahepat ic bile duc t s, is a disorder t hat is primarily c harac t erized by sac c ular or f usif orm dilat at ion of t he int rahepat ic biliary t ree (141). Alt hough originally enc ompassed in t he T odani c lassif ic at ion as a t y pe V c holedoc hal c y st , t his disorder is now t hought t o be a dist inc t ent it y t hat result s f rom abnormal remodeling of t he duc t al plat e, t he embry ologic prec ursor of t he int rahepat ic bile duc t s (66,141,173). Nev ert heless, t he lit erat ure suggest s an P.947 assoc iat ion bet w een Caroli disease and ext rahepat ic bile duc t dilat at ion (141).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2050

13 - The Biliary Tract F igure 13- 29 Met ast asis t o t he gallbladder. A: Nonc ont rast c omput ed t omography (CT ) at t he lev el of t he gallbladder show s a subt le, peripheral, medium- densit y lesion (ar r ow heads), slight ly higher in at t enuat ion t han

adjac ent bile. B: Cont rast - enhanc ed CT at t he same lev el demonst rat es bright art erial enhanc ement of t he gallbladder mass in t he art erial phase. C : Port al phase image show s ret ent ion of c ont rast w it hin t he lesion. Met ast at ic renal c ell c arc inoma t o t he gallbladder w as diagnosed.

T w o f orms of Caroli disease hav e been desc ribed. T he so- c alled simple or pure f orm of t he disease, w hic h most c losely approximat es t he original desc ript ion, is quit e rare, and is c harac t erized by duc t al dilat at ion w it hout f ibrosis (66,170). Pat ient s present w it h sy mpt oms of c holangit is or hepat ic absc ess, inc luding rec urrent at t ac ks of right upper quadrant pain and f ev er, but do not dev elop c irrhosis. T he more c ommon f orm of Caroli disease is heredit ary , and is assoc iat ed w it h periport al f ibrosis, w hic h leads t o t he dev elopment of c irrhosis and port al hy pert ension (77). At c holangiography , alt ernat ing areas of duc t al dilat at ion and st ric t ure are seen. In one series, int raduc t al c alc uli w ere f ound in almost one half of c ases and w ere v isible c holangiographic ally in sev en of eight pat ient s w it h pat hologic ally c onf irmed st ones (141). CT t y pic ally demonst rat es c y st ic st ruc t ures, w hic h represent t he dilat ed bile duc t s imaged in c ross sec t ion. T he ext ent of inv olv ement may v ary f rom f oc al t o generalized. T he f inding of a c ent ral enhanc ing f oc us, t ermed t he c ent r al dot sign, is helpf ul in dist inguishing t he dilat ed biliary segment s of Caroli disease f rom ot her hepat ic c y st s (37) (F ig. 13- 31). Pat hologic ally , t hese dot s hav e been show n P.948 t o c orrespond t o port al v ein radic als, w hic h hav e been engulf ed by t he dilat ed duc t s.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2051

13 - The Biliary Tract

F igure 13- 30 Choledoc hal c y st . A: Cont rast - enhanc ed axial T 1- w eight ed image at t he lev el of t he panc reat ic head show s homogenous, w ell- marginat ed duc t al dilat at ion (ar r ow heads) w it hout enhanc ement . No mass or f illing def ec t is det ec t ed. B: T hic k- slab T 2- w eight ed magnet ic resonanc e c holangiopanc reat ography of t he biliary duc t s show s f usif orm dilat at ion of t he ext rahepat ic bile duc t (ar r ow s) w it hout int rahepat ic dilat at ion.

Guy et al. desc ribed t hree pat t erns of Caroli disease at MRI (77). In t he f irst pat t ern, f usif orm and c y st ic dilat at ion of t he int rahepat ic bile duc t s w as seen, and a c ent ral dot w as demonst rat ed on gadolinium- enhanc ed sc ans. T he sec ond pat t ern w as c harac t erized by isolat ed, f usif orm int rahepat ic duc t al dilat at ion, w hile t he t hird pat t ern show ed dilat at ion of lef t int rahepat ic duc t s, in addit ion t o hepat ic c y st s.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2052

13 - The Biliary Tract F igure 13- 31 Caroli disease. A: Cont rast - enhanc ed c omput ed t omography of t he liv er show s numerous non- enhanc ing c y st ic st ruc t ures (ar r ow s) in t he hepat ic parenc hy ma. T hese represent f oc ally dilat ed biliary duc t s. B: Magnif ied image of t he liv er show s c ent ral f oc i of high densit y (ar r ow heads), w hic h represent v essels surrounded by t he dilat ed duc t s, t he “ c ent ral dot ” sign.

P.949

Choledocholithiasis In most c ases, st ones w it hin t he bile duc t migrat e f rom t he gallbladder. Calc uli t hat primarily f orm w it hin t he bile duc t s are relat iv ely unc ommon, and may be seen in pat ient s w it h biliary st ric t ures, c holangit is, c holedoc hal c y st s, or Caroli disease (4). A minorit y of pat ient s w it h c ommon duc t st ones are asy mpt omat ic . More c ommonly , pat ient s present w it h pain and jaundic e, or possibly f ev er, if t here is assoc iat ed c holangit is. Mult iple noninv asiv e met hods hav e been used f or t he diagnosis of c alc uli in t he bile duc t s, inc luding sonography , unenhanc ed CT , enhanc ed CT , CT w it h oral or int rav enous biliary c ont rast agent s, and MRCP. As prev iously not ed, sonography is of t en used as t he f irst - line imaging modalit y in pat ient s w it h suspec t ed c holedoc holit hiasis. How ev er, sonography of t he c ommon duc t is part ic ularly limit ed by operat or dependenc e. Alt hough t he report ed sensit iv it y of ult rasound in t he det ec t ion of c holedoc holit hiasis is as high as 77% (97), t he dist al CBD may be obsc ured by ov erly ing bow el gas, and a small st one in a nondilat ed duc t c an be missed (249). Cronan f ound t hat t he sensit iv it y of sonography w as higher in t he proximal c ommon duc t t han in it s dist al segment (40). Despit e t he av ailabilit y of new er t ec hniques, suc h as harmonic imaging, a normal sonogram st ill does not reliably exc lude t he diagnosis of c holedoc holit hiasis (185,249). Alt hough CT is usually not perf ormed spec if ic ally t o diagnose c holedoc holit hiasis, CT has demonst rat ed suf f ic ient sensit iv it y and spec if ic it y t o w arrant it s use as a sc reening t est , part ic ularly in pat ient s in w hom ERCP is c ont raindic at ed. In a st udy c omparing unenhanc ed helic al CT w it h sonography and ERCP, Pic kut h and Spielmann f ound t hat unenhanc ed CT had a sensit iv it y of 86% and a spec if ic it y of 98% f or t he det ec t ion of c ommon duc t c alc uli (193). In anot her st udy by Neit lic h et al. (179), unenhanc ed CT ac hiev ed a sensit iv it y and spec if ic it y of 88% and 97%, respec t iv ely , w hereas Cuenc a et al. (43) f ound a CT sensit iv it y of 80% and a spec if ic it y of 100%. In t heir

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2053

13 - The Biliary Tract series, t he most c ommon CT appearanc e of c holedoc olit hiasis w as a highdensit y c alc if ic at ion w it hin t he duc t (F ig. 13- 32) (43). A f oc al sof t t issue densit y surrounded by bile or a high- at t enuat ion ring surrounded by bile w as seen less c ommonly . When unenhanc ed CT is perf ormed spec if ic ally t o assess f or c holedoc holit hiasis, init ial loc alizer sc ans are obt ained t o det ermine t he lev el f or subsequent imaging. Next , 5- mm images are obt ained f rom abov e t he

gallbladder f ossa t hrough t he bot t om of t he unc inat e proc ess of t he panc reas in a single breat h- hold. T he dat a set is t hen rec onst ruc t ed at 1- mm int erv als. Ref ormat t ed mult iplanar, maximum int ensit y projec t ion, and shaded surf ac e display images also may be generat ed in selec t ed c ases. Oral c ont rast should be w it hheld, as it may reduc e t he c onspic uit y of dist al c ommon duc t c alc uli. As not ed prev iously , t he pot ent ial role of CT in c onjunc t ion w it h biliary c ont rast agent s, so- c alled CT c holangiography , remains unc lear, alt hough some inv est igat ors hav e ac hiev ed promising result s. In a st udy of 101 pat ient s w ho rec eiv ed t he c holangiographic agent iot roxic ac id int rav enously , Giadas et al. ac hiev ed a 95.5% sensit iv it y f or det ec t ion of duc t al c alc uli (29). MRCP has show n good sensit iv it y (86% t o 100%) and spec if ic it y (85% t o 100%) f or duc t al st ones, relat iv e t o ERCP (48,147,149,150,158,227,246,247). T he st ones are det ec t ed as f oc al round or linear low signal v oids part ially or c omplet ely surrounded by high T 2 signal bile w it hin t he duc t s (62) (F ig. 1333). An impac t ed st one may not be c omplet ely surrounded by bile, and it may simulat e a st ric t ure (21). Oc c asionally , int rahepat ic biliary c alc uli may be det ec t ed on MRCP (127,224), and MRCP is signif ic ant ly more sensit iv e t han ERCP f or int rahepat ic c alc uli (97% v ersus 59%) (119). T he bile duc t s are normally v isible on MRCP in nonobst ruc t ed pat ient s, but duc t al st ones are easily seen in t he set t ing of biliary dilat at ion w it h a sensit iv it y and spec if ic it y of 94% and 93%, respec t iv ely (94). T he t hin- slic e sequenc es are best f or st one det ec t ion bec ause t he t hic k- slab images may obsc ure t he st one due t o v olume av eraging (34). How ev er, some st udies hav e show n similar abilit y of t hic k- slab HAST E and RARE c ompared w it h t hin- slic e imaging in t he det ec t ion of duc t al st ones (226). A limit at ion of MRCP f or duc t al st ones relat es t o f alse posit iv e f indings due t o art if ac t s. Air bubbles, c lot , poly ps, met al, and f low relat ed art if ac t s may simulat e duc t c alc uli (85). In some c ases, quest ionable f indings on T 2w eight ed MRCP images may be answ ered w it h T 1- w eight ed images. F or inst anc e, met al may hav e “ bloom” art if ac t on T 1 due t o met al

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2054

13 - The Biliary Tract

susc ept ibilit y art if ac t . T he similar appearanc e of t hese ot her f indings t o duc t al c alc uli may limit t he usef ulness of posit iv e f indings, but a negat iv e st udy may prec lude t he need f or inv asiv e ERCP (63,257).

Cholangitis Ac ut e c holangit is usually result s f rom bac t erial inf ec t ion of an obst ruc t ed biliary t ree. Lef t unt reat ed, ac ut e c holangit is may be lif e- t hreat ening by it self or lead t o t he f ormat ion of hepat ic absc esses. Bac t eria reac h t he obst ruc t ed bile duc t s in ret rograde f ashion f rom t he gast roint est inal t rac t or v ia t he port al v enous sy st em (82). Imaging is usually direc t ed t ow ard ident if y ing t he sourc e of obst ruc t ion or inf ec t ion rat her t han making t he diagnosis. T hic kening of t he bile duc t may be seen w it h sonography , CT , or MRI, and c ont rast enhanc ed CT or MRI may demonst rat e mural enhanc ement (F ig. 13- 34). In addit ion, Arai et al. f ound nodular, pat c hy , w edge- shaped, or geographic areas of het erogeneous art erial phase enhanc ement in 11 of 13 pat ient s w it h ac ut e c holangit is (13). Not ably , t hese c hanges eit her dec reased or resolv ed af t er t reat ment . MRCP may demonst rat e irregularit y and beading of t he int rahepat ic bile duc t s (F ig. 13- 35). T he t erm Mir izzi sy ndr om e ref ers t o obst ruc t ion of t he CBD or CHD, usually in t he set t ing of gallbladder nec k P.950 or c y st ic duc t obst ruc t ion by one or more impac t ed st ones (2). T he propensit y f or t he sy ndrome is enhanc ed in pat ient s in w hom t he c y st ic duc t parallels t he CHD (153). Sinc e t he sy ndrome's original desc ript ion, t he def init ion has been expanded t o inc lude v ariant s in w hic h st ones pass int o t he CHD v ia a c holec y st oc holedoc hal f ist ula (42). Pat ient s t y pic ally present w it h obst ruc t iv e jaundic e, of t en w it h abdominal pain and f ev er. Bot h sonography and CT c an demonst rat e t he impac t ed st one or st ones as w ell as int rahepat ic biliary dilat at ion and a normal c aliber c ommon duc t below t he sit e of obst ruc t ion (F ig. 13- 36) (2).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2055

13 - The Biliary Tract

F igure 13- 32 Choledoc olit hiasis. A: Nonc ont rast c omput ed t omography t hrough t he lev el of t he panc reat ic head demonst rat es a f oc al c alc if ic at ion w it hin t he dist al CBD c ommon bile duc t (ar r ow ). B: Cont rast - enhanc ed c omput ed t omography of t he same region show s t he c alc if ic at ion w it h an adjac ent rim of low er- densit y bile (ar r ow s), c onsist ent w it h a bile duc t st one (t he c resc ent sign).

F igure 13- 33 Choledoc olit hiasis. A: T hic k- slab T 2- w eight ed magnet ic resonanc e c holangiopanc reat ography of t he biliary sy st em depic t s a round signal v oid (ar r ow ) in t he dist al duc t w it hin t he hy perint ense bile. B: T hinslic e T 2- w eight ed magnet ic resonanc e imaging MRI show s t he normal c aliber of t he duc t (ar r ow head) dist al t o t he st one.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2056

13 - The Biliary Tract

F igure 13- 34 Cholangit is. Cont rast - enhanc ed T 1- w eight ed magnet ic resonanc e image of t he liv er show s bright enhanc ement of t he int rahepat ic biliary radic als (ar r ow s), c onsist ent w it h biliary inf lammat ion.

P.951

Recurrent Pyogenic Hepatitis F ormerly know n as or ient al c holangiohepat it is, rec urrent py ogenic hepat it is is c harac t erized by int ra- and ext rahepat ic pigment st ones, w it h result ant episodes of py ogenic c holangit is (83). T he disease is endemic t o Sout heast Asia, but is being seen w it h inc reasing f requenc y in t he Unit ed St at es and ot her c ount ries w it h large numbers of Sout heast Asian immigrant s. Pat ient s present w it h rec urrent at t ac ks of abdominal pain ac c ompanied by jaundic e and f ev er. P.952 Pat hologic ally , t he af f ec t ed bile duc t s are dilat ed and c ont ain mult iple, sof t , pigment ed c alc uli and pus (144). CT or sonography may demonst rat e mult iple int ra- or ext rahepat ic c alc uli and v ary ing degrees of int rahepat ic bile duc t dilat at ion, w hic h may be mild or segment al (145).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2057

13 - The Biliary Tract

F igure 13- 35 Cholangit is. T hic k- slab magnet ic resonanc e c holangiopanc reat ography show s irregularit y of t he int rahepat ic bile duc t s (ar r ow heads).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2058

13 - The Biliary Tract F igure 13- 36 Mirizzi sy ndrome. A: Cont rast - enhanc ed c omput ed t omography of t he gallbladder f ossa show s a c alc ulus in t he c y st ic duc t (ar r ow head) adjac ent t o a c ommon duc t st ent (ar r ow ). B: Endosc opic ret rograde c holangiopanc reat ography demonst rat es a round f illing def ec t in t he c y st ic duc t (ar r ow heads) and mild proximal biliary dilat at ion.

AIDS Cholangiopathy AIDS c holangiopat hy is a c omplic at ion of AIDS. T he sy mpt oms are nonspec if ic , and pat ient s present w it h abdominal pain, nausea, f ev er and jaundic e. Most c ommonly , t he c ausat iv e organism is c ry pt osporidium, a parasit e t hat c auses only mild sy mpt oms in host s w it h int ac t immune sy st ems. How ev er, in immunoc ompromised pat ient s, c ry pt osporidium may c ause w ast ing and diarrhea (169). In some pat ient s, CMV c an be a sec ondary c ause of AIDS c holangiopat hy (71). Sonography may demonst rat e biliary dilat at ion, mural t hic kening inv olv ing t he gallbladder or bile duc t s (F ig. 13- 37), and inc reased ec hogenic it y adjac ent t o t he duc t s (206,222). How ev er, t he gallbladder t hic kening is usually inc ident al (222). An ec hogenic nodule at t he dist al CBD, t hought t o represent an edemat ous papilla, has also been desc ribed (45). T he CT appearanc e mirrors t he appearanc e on ult rasound, w it h mural w all t hic kening and t hic kening of t he gallbladder w all (71). Unf ort unat ely , how ev er, t reat ment opt ions are limit ed.

Primary Sclerosing Cholangitis PSC is a c hronic c holest at ic liv er disease, w hic h is c harac t erized by inf lammat ion, dest ruc t ion, and f ibrosis of t he bile duc t s (84,110,177). T he smaller int rahepat ic biliary radic als are oblit erat ed, and t he larger duc t s dev elop irregular st ric t ures. Ev ent ually , t hese c hanges lead t o t he dev elopment of c irrhosis, port al hy pert ension, and liv er f ailure.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2059

13 - The Biliary Tract

F igure 13- 37 AIDS c holangiopat hy . Gray sc ale ult rasound of t he gallbladder show s dif f use sy mmet ric gallbladder w all t hic kening (W) w it hout gallst ones.

Most PSC pat ient s are male, and most hav e assoc iat ed inf lammat ory bow el disease, t y pic ally ulc erat iv e c olit is or Crohn disease (5,84,110). T here is also an assoc iat ion w it h ot her f orms of f ibrosis, inc luding ret roperit oneal and mediast inal f ibrosis (19). Bec ause sy mpt oms usually dev elop insidiously , it is dif f ic ult t o det ermine t he prec ise age of onset , how ev er t he diagnosis is usually made lat e in t he t hird or in t he f ourt h dec ade (5,84). Pat ient s usually present w it h prurit us, w hic h may be more sy mpt omat ic at night and during w arm w eat her (137). St eat orrhea, malabsorpt ion of f at - soluble v it amins, ost eoporosis, and c holangit is may also dev elop. As not ed, c irrhosis and it s manif est at ions may ev ent ually ensue (as disc ussed lat er). Pat ient s w it h PSC also hav e an inc reased inc idenc e of c holangioc arc inoma, w hic h is disc ussed in t he sec t ion on malignant biliary neoplasm. Alt hough bioc hemic al abnormalit ies are c ommonly f ound in pat ient s w it h PSC, t hese f indings are nev er diagnost ic (138). T he serum alkaline phosphat ase and aminot ransf erase lev els are usually elev at ed. Serum albumin is usually not elev at ed early in t he disease c ourse unless t he pat ient also has ac t iv e inf lammat ory bow el disease. Bilirubin lev els are usually normal early on, but rise subsequent ly . Inc reased serum and hepat ic c opper lev els are ot her f eat ures of PSC and are t hought t o ref lec t c holest asis (84,138). T he majorit y of pat ient s w it h PSC also exhibit ant ineut rophic c y t oplasmic ant ibodies.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2060

13 - The Biliary Tract T he c ause of PSC remains spec ulat iv e, alt hough v arious f ac t ors t hat c ause rec urring injury t o t he bile duc t s hav e been proposed as et iologic f ac t ors (138). T he c lose assoc iat ion of PSC w it h ulc erat iv e c olit is has led some inv est igat ors t o suggest t hat port al bac t eremia or exposure t o ot her t oxins may play a role; how ev er, lit t le support iv e ev idenc e has been f ound f or t his t heory (178). More rec ent ly , v arious genet ic and immunologic al c auses hav e been suggest ed. In part ic ular, human leukoc y t e ant igen prof iles t hat hav e been assoc iat ed w it h v arious aut oimmune c ondit ions, suc h as insulin-

dependent diabet es mellit us and my ast henia grav is, hav e also been assoc iat ed w it h PSC (245). Liv er biopsy is generally rec ommended f or st aging of PSC (177). Pat hologic ally , t he af f ec t ed bile duc t s show areas of mural f ibrous t hic kening w hic h alt ernat e w it h segment s of sac c ular or t ubular dilat at ion (177). Vary ing degrees of inf lammat ory inf ilt rat ion are seen w it hin t he duc t al w all. As t he disease progresses, t here is more inv olv ement of t he adjac ent hepat oc y t es, w hic h leads t o t he f inal, c irrhot ic st age. Unf ort unat ely , t reat ment opt ions are f ew and inef f ec t iv e. Alt hough ort hot opic liv er t ransplant at ion has been at t empt ed, c linic ally signif ic ant PSC is likely t o rec ur (128). Sev eral v ariant s of PSC hav e been desc ribed. In so- c alled small bile duc t PSC, also somet imes ref erred t o a per ic holangit is, t he af f ec t ed duc t s are t oo small t o be imaged c holangiographic ally (177,138). T his f orm may oc c ur in isolat ion in pat ient s w it h ulc erat iv e c olit is or in assoc iat ion w it h large- duc t PSC. As w ell, sec ondary f orms of sc lerosing c holangit is are being diagnosed w it h inc reasing f requenc y P.953 in a w ide range of c ondit ions, inc luding immunodef ic ienc y (sev ere c ombined f orm immunodef ic ienc y or HIV), isc hemia, drug t oxic it y , and rec urrent c holangit is. T here is anot her group of PSC pat ient s in w hom aut oant ibodies are f ound in t he serum and w ho hav e hist opat hologic f eat ures of aut oimmune hepat it is, t ermed t he aut oim m une hepat it is and PSC ov er lap sy ndr om e (84,177). T his v ariant is more c ommon in c hildren. Chemot herapy - induc ed c holangit is is a spec if ic f orm of sec ondary sc lerosing c holangit is t hat is seen in pat ient s w ho rec eiv e int ra- art erial inf usion of c hemot herapeut ic agent s f or met ast at ic c olorec t al c anc er, part ic ularly f loxuridine. Ef f ec t s on t he bile duc t s represent eit her direc t t oxic it y or isc hemia, and manif est radiologic ally as int ra- or ext rahepat ic bile duc t

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2061

13 - The Biliary Tract st enoses, w hic h may w orsen t he prognosis of t he underly ing met ast at ic disease (8,254).

Imaging of Primary Sclerosing Cholangitis Cholangiography remains t he gold st andard f or t he diagnosis of PSC. ERCP is generally pref erred ov er direc t , perc ut aneous c holangiography bec ause t he at t enuat ed bile duc t s may be dif f ic ult t o c annulat e perc ut aneously (138). Early in t he disease proc ess, t he af f ec t ed ext rahepat ic bile duc t s may show only mild mural irregularit y or nodularit y (84,138,194). Subsequent ly , t he c harac t erist ic f indings inc lude mult if oc al int ra- and ext rahepat ic bile duc t st ric t ures w it h int erv ening normal or dilat ed segment s, result ing in a so- c alled pruned and beaded appearanc e (F ig. 13- 38). Mult iple div ert ic ulumlike out pouc hings are anot her lat e f inding (194). F or t he most part , t he CT appearanc e of PSC mirrors t he c holangiographic f indings. In a st udy of 20 pat ient s w it h PSC by T eef ey et al., CT demonst rat ed nodularit y of t he ext rahepat ic duc t , pruning of t he int rahepat ic duc t s, and st enosis and dilat at ion in bot h regions (238). How ev er, neit her pruning nor beading are spec if ic f or PSC bec ause t hese f indings are also present in pat ient s w it h ot her t y pes of benign and malignant biliary obst ruc t ion (239).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2062

13 - The Biliary Tract F igure 13- 38 Primary sc lerosing c holangit is. Endosc opic ret rograde c holangiopanc reat ography show s mult if oc al st ric t ures (ar r ow s) inv olv ing t he int rahepat ic and ext rahepat ic biliary duc t s.

Int erest ingly , t he hepat ic morphologic abnormalit ies in PSC, w hic h hav e generally been desc ribed as similar t o t hose f ound in ot her f orms of c irrhosis, do appear t o be dif f erent , and may f ac ilit at e t he diagnosis in pat ient s w it h adv anc ed c irrhosis (49). T hese f indings inc lude marked lobulat ion of t he liv er c ont our, at rophy of t he post erior and lat eral segment s (30), and hy pert rophy of t he c audat e. As w ell, t he hy pert rophied c audat e lobe may be higher in at t enuat ion t han t he rest of t he liv er on unenhanc ed sc ans, c reat ing t he appearanc e of a pseudot umor (F ig. 13- 39).

Magnetic Resonance Imaging of Primary Sclerosing Cholangitis T he t y pic al MRI f indings of PSC inc lude biliary st ric t ures inv olv ing t he int rahepat ic or ext rahepat ic bile duc t s, div ert ic ula w it h beaded appearanc e of t he duc t s, w ebs, duc t al st ones, and duc t irregularit y (F ig. 13- 40) (253). Ernst et al. not ed peripheral duc t al dilat at ion t hat did not c ommunic at e w it h c ent ral duc t s due t o st ric t ures (53). T here may be w all t hic kening or abnormal w all enhanc ement on c ont rast - enhanc ed T 1- w eight ed images (102). T he sensit iv it y and spec if ic it y of MRCP f or PSC are 85% t o 100%, and 92% t o 100%, respec t iv ely (53,64). Dilat at ion and good v isualizat ion of t he peripheral duc t s on MRCP are c onsidered abnormal and are due t o P.954 mult iple st ric t ures. In one st udy , t he int rasegment al and peripheral duc t s w ere more of t en v isible in PSC pat ient s t han in a c ont rol group (86% v ersus 9%, and 67% v ersus 0%, respec t iv ely ) (252). F urt hermore, a proximal st ric t ure in t he set t ing of PSC may limit t he v isualizat ion of t he ext rahepat ic bile duc t s on MRCP (251). In a c omparison of MRCP and ERCP, t he most c ommon reason f or disagreement bet w een t he modalit ies is a st ric t ure suspec t ed on MRCP t hat is not ident if ied on ERCP (251).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2063

13 - The Biliary Tract

F igure 13- 39 Primary sc lerosing c holangit is w it h pseudot umor of c audat e lobe. On a nonc ont rast c omput ed t omography image, t he massiv ely enlarged c audat e lobe (CL) appears slight ly denser t han t he adjac ent liv er parenc hy ma (ar r ow s).

F igure 13- 40 Primary sc lerosing c holangit is. A: Cont rast - enhanc ed T 1w eight ed images of t he liv er show int rahepat ic biliary dilat at ion (ar r ow s). B: T hic k- slab magnet ic resonanc e c holangiopanc reat ography show s mult if oc al

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2064

13 - The Biliary Tract st ric t ures w it h a “ beaded” appearanc e of t he int rahepat ic duc t s (ar r ow s). T he c ommon duc t (C) is irregular, but has a normal c aliber.

Parasitic Infection of the Bile Ducts Parasit ic inf ec t ion of t he biliary t ree is unc ommonly enc ount ered in Nort h Americ a, but is seen in endemic areas suc h as Sout heast Asia. Int est inal asc ariasis is c aused by Asc ar is lum br ic oides, w hic h is t he most c ommon c ause of human helmint hic inf est at ion (98). T he inf ec t ion generally has a benign c ourse, but w orms may ent er t he biliary t ree v ia t he ampulla of Vat er (6) and c ause c holangit is and, rarely , liv er absc esses. T he CT appearanc e is nonspec if ic , but sonography may demonst rat e t ubular st ruc t ures w it hin t he bile duc t s or gallbladder. A similar appearanc e has been report ed at MRCP (58,98). Dead w orms may also ac t as a nidus f or st one f ormat ion, usually in t he gallbladder, t he CBD, or t he lef t int rahepat ic duc t s. T he liv er f lukes Clinor c his sinensis and Opist hor c his v iv er r ini also may inf ec t t he biliary t ree. As in pat ient s w it h asc ariasis, mild inf ec t ions may go unnot ic ed. How ev er, heav y inf est at ions c an lead t o w orms w it hin t he gallbladder, t he ext rahepat ic bile duc t s, and t he panc reas (120). At CT , t he diagnosis may be suspec t ed in t he presenc e of mild, ext rahepat ic biliary dilat at ion, enlargement of t he body and/or t ail of t he panc reas, and small, peripherally enhanc ing c y st s w it hin t he panc reas.

Biliary Duct Neoplasms T he bile duc t s giv e rise t o a v ariet y of benign and malignant t umors, of w hic h c holangioc arc inoma is t he most c ommon. Ot her bile duc t neoplasms, inc luding c y st adenoma, adenoma, and papilloma, are enc ount ered f ar less f requent ly , and w ill be disc ussed subsequent ly .

Cholangiocarcinoma Cholangioc arc inoma is a malignant neoplasm t hat arises f rom c holangioc y t es, w hic h f orm t he epit helial lining of t he bile duc t s (72). T he v ast majorit y are adenoc arc inomas, alt hough sev eral ot her hist ologic subt y pes hav e been desc ribed (263). T he t umor is most c ommonly f ound in older pat ient s, w it h 65% older t han age 65 y ears (117). Alt hough st ill relat iv ely unc ommon, t here has been a rec ent inc rease in t he inc idenc e of c holangioc arc inoma (72).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2065

13 - The Biliary Tract

Bet w een 1973 and 1997, t he inc idenc e and mort alit y rat es inc reased markedly , w it h an est imat ed annual c hange of 9.11% and 9.44%, respec t iv ely (190). Alt hough t he et iology of c holangioc arc inoma remains unc ert ain, a number of c ondit ions hav e been ident if ied as predisposing f ac t ors (35). Of t hese, PSC has t he st rongest assoc iat ion. Oc c ult c holangioc arc inoma is f ound in up t o 40% of aut opsy spec imens in PSC pat ient s (1,27,36,207). P.955 T he inc idenc e of c holangioc arc inoma is also inc reased in pat ient s w it h biliary c y st ic disease, inc luding c holedoc hal c y st s and Caroli disease, presumably bec ause of c hronic biliary inf lammat ion (47). Pat ient s w it h parasit ic inf ec t ions of t he bile duc t s, part ic ularly C. sinensis, are also at higher risk f or c holangioc arc inoma, as are pat ient s w it h rec urrent py ogenic hepat it is, c hronic t y phoid c arriers, and pat ient s w it h a hist ory of T horot rast exposure (35,117). T he c ommon t hread linking t hese risk f ac t ors t o c holangioc arc inoma appears t o be c hronic inf lammat ion, w hic h is also assoc iat ed w it h t umors in ot her part s of t he gast roint est inal t rac t (72). Cy t okines released by c holangioc y t es and inf lammat ory c ells c ause t he c holangioc y t es t o express induc ible nit ric oxide sy nt hase, w hic h generat es nit ric oxide, leading t o DNA damage (104). Int erleukin- 6, anot her c y t okine, also appears t o play an import ant role as a mit ogenic agent (187).

Clinical Aspects and Classification of Cholangiocarcinoma Cholangioc arc inoma c an arise f rom any point in t he biliary epit helium, f rom t he int rahepat ic biliary radic als t o t he ampulla of Vat er (35,80,136). Bec ause t he behav ior of c holangioc arc inoma is in part relat ed t o it s sit e of origin w it hin t he biliary t ree, t he most c ommonly employ ed c lassif ic at ion sc heme div ides t umors int o int ra- and ext rahepat ic t y pes. Int rahepat ic c holangioc arc inoma is f urt her c lassif ied int o peripheral and perihilar subt y pes, w it h t he f ormer arising peripheral t o t he sec ond bif urc at ion of t he right or lef t hepat ic duc t (80,136). Perihilar c holangioc arc inomas, w hic h arise at t he c onf luenc e of t he hepat ic duc t s, c ommonly know n as Klast kin t um or s, are t he most c ommon t y pe of t hese t umors, c omprising up t o 60% of t he t ot al (35,117). T oget her, int rahepat ic and perihilar t umors c omprise approximat ely 75% t o 80% of t he t ot al. Ext rahepat ic lesions, w hic h arise along t he CHD or CBD, make up t he remainder, and are subdiv ided by t heir lev el

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2066

13 - The Biliary Tract

along t he c ommon duc t (upper, middle, or low er t hird). Some aut hors c onsider perihilar and ext rahepat ic c holangioc arc inomas as a single ent it y , sinc e t hey t end t o hav e similar grow t h pat t erns (72,80,136). T o a large ext ent , t he c linic al present at ion of c holangioc arc inoma depends on it s lev el of origin. T umors w it h result ant biliary obst ruc t ion w ill c ause painless jaundic e, w hic h is seen in up t o 90% of c ases, and w eight loss is seen in 50% (263). Right upper quadrant pain, f ev er, and c hills suggest superimposed c holangit is (117). Peripheral, int rahepat ic c holangioc arc inomas, on t he ot her hand, present w it h signs and sy mpt oms of a liv er mass, inc luding pain, w eight loss, night sw eat s, and malaise (72). T he serum alkaline phosphat ase lev el is of t en elev at ed, but t he bilirubin lev el is usually normal. While t here are no spec if ic t umor markers f or c holangioc arc inoma, lev els of c anc er ant igen 19- 9, c arc inoembry onic ant igen, and c anc er ant igen 125 may be abnormal (72,117,242).

Growth Patterns and Approach to Diagnosis and Staging of Cholangiocarcinoma In addit ion t o loc at ion w it hin t he biliary t rac t , grow t h pat t ern play s an import ant role in det ermining t he imaging appearanc e of c holangioc arc inoma in a giv en pat ient . F our t y pes of grow t h pat t ern hav e been desc ribed (136). T he exophy t ic f orm, in w hic h t he t umor grow s out side of t he bile duc t s and f orms a mass, is t he most c ommon pat t ern enc ount ered in peripheral c holangioc arc inomas (80,136). An inf ilt rat iv e pat t ern, w hic h is c harac t erized by desmoplast ic t umor t hat grow s along and engulf s bile duc t s and blood v essels, is more t y pic al of perihilar and ext rahepat ic t umors (72,136). T his pat t ern of direc t spread oc c urs in more t han 70% of perihilar lesions (80). A poly poid grow t h pat t ern, w it h predominant ly int raluminal grow t h, is seen in a minorit y of int ra- and ext rahepat ic c holangioc arc inomas. F inally , a c ombined grow t h pat t ern has also been desc ribed (136). In pat ient s w ho present w it h a peripheral hepat ic mass, a pat hologic diagnosis of c holangioc arc inoma c an usually be obt ained by perc ut aneous biopsy under CT or ult rasound guidanc e. Inf ilt rat iv e t umors present more of a diagnost ic c hallenge bec ause t he t umor of t en ext ends along t he submuc osal spac e (72). Bile sampling f or c y t ology c an be perf ormed in c onduc t ion w it h ERCP or PT C, but is posit iv e in only 30% of c ases; c ombining brush c y t ology w it h biopsy inc reases t he y ield t o 40% t o 70% (117). Despit e diligent ef f ort , how ev er, a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2067

13 - The Biliary Tract pat hologic diagnosis may not be f easible in some pat ient s, and t he diagnosis must be based on a c omposit e of c linic al c rit eria (72). T he goal of init ial imaging in pat ient s w it h suspec t ed or know n c holangioc arc inoma is t o det ermine suit abilit y f or surgic al resec t ion, w hic h c urrent ly of f ers t he only possibilit y of c ure. Alt hough t here is a t umor, node, met ast asis (T NM) st aging sy st em f or c holangioc arc inoma, it is not reliable f or

c linic al assessment or predic t ion of surv iv al (72,263). Anot her st aging sc heme dev ised by Bismut h c lassif ies perihilar t umors by t he degree of inv olv ement of t he right and lef t hepat ic duc t s, w hic h is usef ul f or surgic al planning (24,210). Assessment of t he ext ent of v asc ular inv olv ement is also c rit ic al, as is t he exc lusion of met ast at ic disease t o t he liv er, ly mph nodes, or perit oneum. Bec ause primary malignanc ies arising in ot her organs, not ably t he panc reas, st omac h, breast , lung, and c olon, may mimic c holangioc arc inoma, imaging may be required t o exc lude t hese possibilit ies if t he diagnosis is in doubt (117).

Computed Tomography of Cholangiocarcinoma T he CT appearanc e of c holangioc arc inoma largely depends on it s sit e of origin. Peripheral, mass- f orming t umors appear as low at t enuat ion lesions on unenhanc ed CT , w it h inc omplet e rim enhanc ement on art erial and port al v enous phase images (F ig. 13- 41) (60,80,118). A low - at t enuat ion appearanc e of t he mass w it hout art erial phase enhanc ement is seen less f requent ly (244). Rarely , c holangioc arc inoma show s marked enhanc ement in t he art erial P.956 phase (265). As not ed prev iously , c holangioc arc inoma may exhibit delay ed enhanc ement , w hic h has been at t ribut ed t o c ont rast dif f usion int o t he int erst it ial spac e w it hin t he f ibrous st roma (115,244) (F ig. 13- 42). T his pat t ern is v ariable, w it h a report ed f requenc y ranging f rom 36% t o 70% (115,152,244). How ev er, w hen delay ed enhanc ement oc c urs, it may permit a presumpt iv e diagnosis of c holangioc arc inoma. Ot her anc illary CT f indings of peripheral int rahepat ic c holangioc arc inoma inc lude regional ly mphadenopat hy , biliary dilat at ion, sat ellit e nodules, and ret rac t ion of t he liv er c apsule (80,244).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2068

13 - The Biliary Tract

F igure 13- 41 Int rahepat ic c holangioc arc inoma. A: Nonc ont rast c omput ed t omography (CT ) image show s a het erogeneous, hy podense mass (M) w it hout c alc if ic at ions. B: Port al v enous phase CT image show s mild enhanc ement .

F igure 13- 42 Int rahepat ic c holangioc arc inoma. Comput ed t omography image of t he same pat ient as in F igure 13- 41 af t er a 10- minut e delay show s ret ent ion of c ont rast in t he mass, w hic h is c learly denser t han t he adjac ent liv er.

In c ont rast t o t he mass- f orming t y pe of int rahepat ic c holangioc arc inoma, int raduc t al t umors are c harac t erized by segment ally - dilat ed bile duc t s w hic h are higher in at t enuat ion t han normal bile (80,133) (F ig. 13- 43). T hese t umors are usually papillary adenoc arc inomas and hav e a bet t er prognosis t han ot her t y pes of c holangioc arc inoma (133,264). Not ably , lesions t hat sec ret e large

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2069

13 - The Biliary Tract amount s of muc in are assoc iat ed w it h duc t al dilat at ion bot h proximal and dist al t o t he t umor. Det ec t ion of t he obst ruc t ing mass it self depends on it s size, w it h masses larger t han 1 c m being v isible on CT . Perihilar and ext rahepat ic c holangioc arc inomas t y pic ally exhibit an inf ilt rat ing grow t h pat t ern (80,136,240). T hese neoplasms are c harac t erized by f oc al, c irc umf erent ial t hic kening of t he bile duc t w it h proximal dilat at ion, w hic h may be seen sonographic ally or at t hin- sec t ion CT (F ig. 13- 44). Conspic uit y of perihilar c holangioc arc inoma is highest on art erial phase images (240). Oc c asionally , perihilar lesions may be similar in appearanc e t o t he

int rahepat ic , mass- f orming t y pe of c holangioc arc inoma, or may manif est as an int raluminal poly poid mass (80,136). T he diagnosis of c holangioc arc inoma in pat ient s w it h PSC c an be part ic ularly c hallenging. At c holangiography , dominant benign st ric t ures are of t en dif f ic ult t o dist inguish f rom malignant st ric t ures, alt hough progressiv e biliary dilat at ion on serial st udies suggest s c omplic at ing c holangioc arc inoma (32). Bec ause of it s abilit y t o depic t t umor masses, part ic ularly t hose t hat inv ade t he liv er parenc hy ma, CT is helpf ul t o monit or pat ient s w it h PSC. T he role of posit ron emission t omography (PET ) imaging in sc reening f or c holangioc arc inoma or st aging pat ient s w it h know n or suspec t ed c holangioc arc inoma has y et t o be det ermined, how ev er, t he t ec hnique show s promise. P.957 In one st udy , v isual analy sis of 18F - f lurodeoxy gluc ose- PET images show ed a sensit iv it y of 92% and a spec if ic it y of 93% in t he diagnosis of 26 pat ient s w it h c holangioc arc inoma, inc luding 4 w it h underly ing PSC (121). In t his st udy , PET w as also helpf ul t o diagnose dist ant met ast ases, but it w as not usef ul f or t he det ec t ion of regional ly mph node inv olv ement .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2070

13 - The Biliary Tract

F igure 13- 43 Int rahepat ic c holangioc arc inoma. A: Cont rast - enhanc ed c omput ed t omography of t he liv er show s biliary dilat at ion w it h dense mat erial (ar r ow s) f illing t he bile duc t s in t he lef t hepat ic lobe. B: Delay ed image demonst rat es persist ent high densit y in t his region.

F igure 13- 44 Ext rahepat ic c holangioc arc inoma. A: Cont rast - enhanc ed c omput ed t omography (CT ) sc an t hrough t he liv er show s ext ensiv e int rahepat ic duc t al dilat at ion. B: Cont rast - enhanc ed CT at t he lev el of t he liv er hilum show s a short segment of a c onc ent ric ally t hic kened c ommon bile duc t w it h mural enhanc ement (ar r ow heads).

A v ariant malignanc y w hic h c ombines element s of c holangioc arc inoma and hepat oc ellular c arc inoma (HCC) also deserv es ment ion (70). T his unusual neoplasm, w hic h P.958

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2071

13 - The Biliary Tract c omprises less t han 5% of primary hepat ic malignanc ies, behav es more like HCC c linic ally (52). Most pat ient s w it h t his t y pe of t umor hav e c irrhosis or c hronic hepat it is B or C, and t he serum alpha- f et oprot ein is elev at ed in most c ases. At CT , c ombined c holangioc arc inoma- HCC exhibit s imaging f eat ures of bot h t y pes of t umor. T hese f eat ures inc lude areas of art erial phase enhanc ement t hat appear hy podense on port al v enous phase or delay ed images, as w ell as areas t hat exhibit t he c ommonly seen delay ed hy perat t enat ion and c apsular ret rac t ion assoc iat ed w it h c holangioc arc inoma.

Magnetic Resonance Imaging of Cholangiocarcinoma MRI may show a low T 1 signal lesion, and t here may be inc reased enhanc ement on delay ed images, as seen on CT . T he lesion should be hy perint ense on T 2- w eight ed sequenc es (3,55,76,229,250) (F ig. 13- 45). Oc c asionally , a t hic kened bile duc t w all is v isualized, and t he w all of t he duc t may demonst rat e abnormal enhanc ement . A w all t hic kness great er t han 5 mm has been suggest ed t o c orrelat e w it h a malignant rat her t han a benign c ause of obst ruc t iv e jaundic e (214). How ev er, c holangit is may also c ause t hic kening of t he bile duc t w all. F or surgic al planning, MRCP may depic t t he c ranial ext ent of t he mass (135) and det ermine w het her bot h lobes of t he liv er are inv olv ed.

Unusual Bile Duct Tumors Benign t umors of t he bile duc t s, most ly biliary adenomas or papillomas, are unc ommon. Mult if oc al biliary papillomas, also know n as biliary papillomat osis, are c harac t erized by mult iple poly poid f illing def ec t s w it hin t he bile duc t s. CT , MRCP, and sonography may demonst rat e a dilat ed biliary t ree w it h endoluminal masses or poorly def ined f illing def ec t s (156). Alt hough t hey are benign, t hese neoplasms hav e a malignant pot ent ial (88). Biliary c y st adenomas are unc ommon c y st ic lesions of t he biliary t ree. T he t y pic al CT appearanc e is a mult iloc ular c y st ic mass w it h a w ell- def ined c apsule and mural nodules (173) (F ig. 13- 46). Poly poid exc resc enc es are suggest iv e of malignant t ransf ormat ion (23). Biliary hamart omas, also know n as Von Mey enbur g c om plex of t he liv er , are benign malf ormat ions of t he bile duc t s w hic h present as small, c y st - like def ormed bile duc t s embedded w it hin dense c onnec t iv e t issue (259). CT show s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2072

13 - The Biliary Tract mult iple, nonenhanc ing f oc i t hroughout bot h lobes of t he liv er (173). At MRI, t he lesions are hy point ense on T 1- w eight ed images and hy perint ense on T 2w eight ed sequenc es. As w it h CT , enhanc ement is usually not seen af t er t he int rav enous administ rat ion of gadolinium.

Nonbiliary Tumors That Affect the Biliary Tree A w ide v ariet y of primary and sec ondary nonbiliary neoplasms af f ec t t he bile duc t s. Among t hese, t he most import ant are periampullary t umors t hat arise f rom t he ampulla of Vat er or t he adjac ent duodenum. T radit ionally , t hese t umors hav e been grouped w it h dist al CBD c holangioc arc inomas and adenoc arc inomas arising in t he panc reat ic head bec ause t hey t y pic ally present w it h biliary and panc reat ic duc t obst ruc t ion (F ig. 13- 47). At present , surgic al resec t ion of f ers t he only possibilit y of c ure (96,205,219). Apart f rom est ablishing a def init iv e diagnosis, t he goal of preoperat iv e imaging in t hese pat ient s is t o det ermine if resec t abilit y is f easible. Crit eria t hat exc lude t he possibilit y of c urat iv e surgic al resec t ion inc lude (a) hepat ic or dist ant met ast ases, (b) inv asion of t he c ont iguous organs or mesent ery (apart f rom t he duodenum), and (c ) obst ruc t ion, enc asement , or inv asion of t he port al v ein, t he superior mesent eric –port al v ein c onf luenc e, t he c eliac axis, or t he superior mesent eric art ery (96,205). In a st udy of 21 pat ient s w it h periampullary malignanc y , How ard et al. f ound t hat helic al CT had a sensit iv it y of 63%, a spec if ic it y of 100%, and an ov erall ac c urac y of 86% in det ermining respec t abilit y (96). EUS w as more sensit iv e but less spec if ic t han CT , w it h a sensit iv it y of 75%, a spec if ic it y of 77%, and an ov erall ac c urac y of 76%. A lat er st udy by Shoup et al. f ound t hat EUS w as superior t o CT in det ec t ing t umor and in predic t ing v asc ular inv asion (219). T hey rec ommended helic al CT as t he init ial imaging modalit y f or st aging periampullary t umors, w it h EUS reserv ed f or pat ient s w it h high c linic al suspic ion but no ident if iable mass at CT or f or pat ient s w it h equiv oc al CT ev idenc e f or v asc ular inv asion. Met ast at ic disease f rom any sourc e c an also obst ruc t t he int ra- or ext rahepat ic bile duc t s if t hey are loc at ed f ort uit ously (F ig. 13- 48). Not surprisingly , t he CT appearanc e of t hese lesions is nonspec if ic . In addit ion, t here hav e been c ase report s of pat ient s w it h benign, f ibrot ic masses at t he hepat ic hilum mimic king perihilar c holangioc arc inoma (86,248). How ev er, t he CT appearanc e of t hese lesions is also nonspec if ic , and a preoperat iv e diagnosis of benign f ibrosis is usually not possible.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2073

13 - The Biliary Tract Biliary Tract Surgery Liver Transplant Evaluation T he preoperat iv e ev aluat ion of t he biliary sy st em f or c adav eric liv er t ransplant at ion is t y pic ally based upon laborat ory v alues, and imaging is not rout inely perf ormed. In liv ing donor liv er t ransplant at ion (LDLT ), how ev er, an underst anding of t he hepat ic anat omy is c rit ic al, and ext ensiv e imaging is of t en obt ained t o ev aluat e art erial, v enous, and biliary anat omy and look f or

v ariant s. Of t hese, anomalous biliary anat omy is more c ommon t han v ariant s of t he port al v enous or hepat ic art erial sy st ems (236). Most of t he v ariat ions c an be ident if ied during surgery and w ill not af f ec t t he proc edure if properly c onsidered (100). How ev er, c holangiography is c ommonly perf ormed during surgery t o prec isely det ermine t he anat omy f or div ision of t he lef t duc t . T he hepat ic art ery branc hes t hat supply t he P.959 duc t s are also import ant bec ause injury t o t he f eeding art ery may result in sev ere biliary nec rosis. Alt hough CT is usef ul f or v asc ular delineat ion, preoperat iv e CT is not sensit iv e f or t he biliary anat omy in t he absenc e of biliary dilat at ion. Alt hough unc ommonly used, posit iv e biliary c ont rast t ec hniques allow CT imaging of t he biliary sy st em w it h int rav enous biliary c ont rast (212).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2074

13 - The Biliary Tract

F igure 13- 45 Magnet ic resonanc e c holangiopanc reat ography (MRCP) of c holangioc arc inoma. A: Axial T 2- w eight ed magnet ic resonanc e image show s dilat ed int rahepat ic duc t s w it h homogenous high T 2 signal (ar r ow s). B: Coronal oblique t hic k- slab MRCP demonst rat es ext ensiv e int rahepat ic hy perint ense T 2 signal duc t dilat at ion t o t he lev el of t he hepat ic hilum, w it h a normal c aliber of t he ext rahepat ic bile duc t (ar r ow ). C : Cont rast - enhanc ed T 1- w eight ed image of t he liv er show s low T 1 signal in t he dilat ed int rahepat ic duc t s (ar r ow heads).

Af t er a pat ient has been approv ed t o rec eiv e a liv er t ransplant , signif ic ant t ime may pass bef ore t hey rec eiv e a new liv er. T here is a signif ic ant w ait - list f or liv er t ransplant at ion, and pat ient s w it h liv er disease may hav e ext ensiv e liv er damage t hat c an inc lude biliary obst ruc t ion. If a liv er allograf t is not av ailable, ERCP may be used t o t reat ac ut e biliary problems, suc h as using

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2075

13 - The Biliary Tract balloon angioplast y f or a st ric t ure, unt il an organ is av ailable. Drainage past st ric t ures or remov al of obst ruc t ing biliary st ones are usually c onsidered t emporizing t reat ment s in t hese pat ient s.

Living Donor Liver Transplantation/Segmental Hepatectomy LDLT has been used in t he pediat ric populat ion w it h good suc c ess. In pediat ric rec ipient s, t he lat eral segment of t he P.960 lef t hepat ic lobe is remov ed f rom t he donor and graf t ed t o t he hepat ic v essels of t he rec ipient . T his proc edure is more c ommon in liv er donat ion t o a c hild, but t he demands upon t he liv er in an adult are more subst ant ial and w ill usually require right hepat ic lobe t ransplant at ion (161). It is import ant t o remember t hat an adequat e amount of liv er must also remain t o sust ain t he donor, so ev aluat ion of t he donor is c rit ic al.

F igure 13- 46 Biliary c y st adenoma. A: Nonc ont rast c omput ed t omography (CT ) of t he liv er demonst rat es a f oc al low - densit y mass w it h subt le sept at ions (ar r ow heads). B: Cont rast - enhanc ed CT show s enhanc ement of t he sept at ions (ar r ow s), but no enhanc ement in t he c y st ic c omponent s of t he mass.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2076

13 - The Biliary Tract

F igure 13- 47 Ampullary mass. A: Hy podense irregular mass (ar r ow s) in t he region of t he ampulla of Vat er on c ont rast - enhanc ed c omput ed t omography . B: Image t hrough t he lev el of t he panc reas show s panc reat ic duc t al dilat at ion (D).

T he ev aluat ion of t he donor liv er may inv olv e a c ombinat ion of mult iple imaging modalit ies suc h as ult rasound, CT , MRI, MRCP, and angiography t o ev aluat e dif f erent aspec t s of t he liv er. Of t hese, MRCP is best suit ed f or P.961 ev aluat ion of t he biliary t ree c onf igurat ion. MRCP is helpf ul t o det ec t v ariant s in t he biliary anat omy prior t o surgery (61). MRI and MRCP may also det ec t any unsuspec t ed biliary pat hology w it hin t he donor t hat may prec lude liv er donat ion. T he v olume of t he liv er segment s is ev aluat ed by CT or MRI t o ensure t hat adequat e donat ed liv er v olume is av ailable t o t he rec ipient (20,148). At t he t ime of surgery , ult rasound may be helpf ul t o ident if y t he v asc ular anat omy and direc t t he loc at ion of t he surgic al resec t ion plane.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2077

13 - The Biliary Tract

F igure 13- 48 Colon c arc inoma met ast ases c ausing biliary obst ruc t ion. A: Cont rast - enhanc ed c omput ed t omography (CT ) show s int rahepat ic biliary dilat at ion and a large, hy podense hepat ic met ast asis (M). B: CT image at t he lev el of t he c ommon duc t depic t s mult iple hy podense ov al masses in t he liv er hilum and peripanc reat ic region (ar r ow heads).

Preoperat iv e det ec t ion of a c holangioc arc inoma is an ominous f inding in a pat ient w ait ing f or liv er t ransplant , ev en if a new liv er is quic kly f ound. It is c onsidered a c ont raindic at ion t o t ransplant at ion bec ause of a high rec urrenc e rat e in t ransplant rec ipient s (201,208).

Postoperative Biliary Complications Sev eral possible c omplic at ions of c holec y st ec t omy inv olv e t he biliary sy st em, and major bile duc t injury is more c ommon w it h laparosc opic c holec y st ec t omy t han open surgery (256). How ev er, ot her st udies hav e c it ed muc h low er rat es of c omplic at ions w hen int raoperat iv e c holangiography is perf ormed (59). Complic at ions in t hese pat ient s are due t o mist aken ident if ic at ion of biliary st ruc t ures (22,225). T hese c omplic at ions inc lude biliary injury , biliary st ric t ure, and ret ained st ones. Ult rasound is usually t he init ial imaging modalit y w hen a c omplic at ion of surgery is a c onc ern, but CT may also det ec t f ree f luid or a c ont ained biloma (F ig. 13- 49). How ev er, biloma is rare af t er laparosc opic c holec y st ec t omy , oc c urring in less t han 3% of pat ient s (7,124,255). Rec ent ly , t here has been inc reasing usage of MRI t o v isualize t he biliary duc t s in pat ient s w it h suspec t ed biliary P.962

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2078

13 - The Biliary Tract c omplic at ions. T he most c ommon f indings are biliary leak, ret ained biliary st ones, and anast omot ic st ric t ure (116). Bile duc t injury w it h biliary leak

appears as hy perint ense T 2- w eight ed signal c ollec t ions of bile w it hin t he liv er or adjac ent t o t he hepat ic hilum on MRI, and oc c asionally t he sit e of leakage c an be ident if ied (78). How ev er, one st udy (39) show ed t hat MRCP had dif f ic ult y dif f erent iat ing c omplet e bile duc t t ransec t ion f rom duc t al oc c lusion. If MRCP is not av ailable, int raoperat iv e c holangiography is one alt ernat iv e t hat may reduc e t he oc c urrenc e of or rapidly ident if y biliary c omplic at ions assoc iat ed w it h laparosc opic c holec y st ec t omy (256).

F igure 13- 49 Complic at ion of laparosc opic c holec y st ec t omy . Cont rast enhanc ed c omput ed t omography of t he hepat ic hilar region show s a large f luid c ollec t ion (F ), c onsist ent w it h a biloma.

St ric t ure is a c ommon c omplic at ion of biliary surgery . As many as 95% of benign biliary st ric t ures oc c ur as a sequela of surgery (131,143). MRCP is a noninv asiv e met hod t o ev aluat e t he ext ent of a st ric t ure and t o det ec t addit ional biliary abnormalit ies. Ret ained st ones in t he bile duc t are anot her possible c omplic at ion of c holec y st ec t omy (F ig. 13- 50). T he st ones are usually loc at ed in t he CBD, but t hey may be f ound w it hin int rahepat ic bile duc t s, as w ell.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2079

13 - The Biliary Tract Many biliary surgeries inv olv e t he c reat ion of a biliary - ent eric anast omosis, w hic h may limit ev aluat ion by ERCP. If t here is suspic ion of a biliary surgic al c omplic at ion, t he bile duc t s usually c annot be ac c essed endosc opic ally in t hese pat ient s. MRCP allow s noninv asiv e met hod of ev aluat ion of t he biliary sy st em in t hese pat ient s.

Liver Transplant Complications In liv er t ransplant at ion, t he donor bile duc t is anast omosed t o t he rec ipient c ommon duc t or t o a loop of small bow el. In most c ases, a direc t anast omosis is c reat ed bet w een t he donor and rec ipient bile duc t s. Choledoc ojejunost omy is c hosen if t he rec ipient duc t is t oo small or diseased (106,180). At t he inst it ut ion of t hese aut hors, a biliary T - t ube is plac ed t o allow easy ev aluat ion of t he duc t s f or early post operat iv e bile leak or st ric t ure. T he biliary t ube is subsequent ly c apped t o allow int ernal drainage, and it is lat er remov ed.

F igure 13- 50 Ret ained gallst ones af t er c holec y st ec t omy . Nonc ont rast c omput ed t omography of t he gallbladder f ossa af t er c holec y st ec t omy show s mult iple ret ained c alc if ied gallst ones (ar r ow ). Not e t he adjac ent c holec y st ec t omy c lip (ar r ow head).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2080

13 - The Biliary Tract Biliary c omplic at ions are c ommon w it hin t he rec ipient af t er c adav eric liv er t ransplant at ion (181). As many as 15% t o 19% of liv er t ransplant at ion rec ipient s experienc e a biliary c omplic at ion (44,73,139,209,232). T y pic al c omplic at ions inc lude biliary leak, st ric t ure, st one f ormat ion, or oc c asionally dif f use biliary nec rosis. Early c omplic at ions of liv er t ransplant at ion are of t en relat ed t o surgic al t ec hnique or loc al isc hemia. T hey may be due t o sc arring, mult if ac t orial c auses, rejec t ion, or c y t omegalov irus inf ec t ion (174). Bile leaks of t en oc c ur early , but st ric t ures may oc c ur mont hs af t er surgery (67). Alt hough deat h is rare, biliary c omplic at ions result in morbidit y and may oc c asionally c ause loss of t he t ransplant ed liv er (14,17,73). In sev ere c ases, dif f use biliary isc hemia assoc iat ed w it h art erial insuf f ic ienc y may be c at ast rophic (F ig. 13- 51) (269). Doppler ult rasound should be t he f irst imaging st udy if a t ransplant biliary abnormalit y is suspec t ed. Biliary dilat at ion c an be c onf ident ly det ec t ed by ult rasound, and t he hepat ic v essels may be ev aluat ed f or hepat ic art ery oc c lusion. Ult rasound may also det ec t perihepat ic or hilar f luid c ollec t ions. A biloma w ill appear as a hy poec hoic or anec hoic c ollec t ion adjac ent t o t he liv er. Likew ise, MRCP and CT may be usef ul t o det ec t biliary dilat at ion or bile leaks, but t hese modalit ies are not c ommonly perf ormed as t he init ial imaging

st udy . Hepat ic 2,6- dimet hy l- iminodiac et ic ac id sc an c an det ec t leaks, but it is not sensit iv e f or st ric t ure. If t here is suspic ion of a st ric t ure or st one, ERCP may allow t herapeut ic int erv ent ion. If sepsis dev elops, perc ut aneous dec ompression of t he biliary sy st em is of t en nec essary by ERCP. PT C w it h drain or st ent plac ement may also be used t o reliev e t he obst ruc t ion. T he proc edure is inv asiv e, but may be used in c ombinat ion w it h ant ibiot ic s t o improv e t he pat ient 's c ondit ion unt il a liv er allograf t bec omes av ailable. Ult rasound is of t en request ed t o prov ide marking or direc t guidanc e f or liv er biopsy , w hic h may be used t o diagnose isc hemia or rejec t ion. Bile leak af t er t ransplant at ion may appear as a f oc al c ollec t ion in t he liv er hilum t hat is low - densit y on CT or low T 1 signal and high T 2 signal on MRI. T he f luid c an t rac k aw ay f rom t he liv er if it is large (F ig. 13- 52). T he point of early leakage, usually at t he T - t ube sit e (198), c an be demonst rat ed on MRCP images. Leaks may also oc c ur f rom t he c y st ic duc t c losure in t he donor or rec ipient duc t . Delay ed leaks most c ommonly oc c ur at t he anast omot ic sit e (186), and biliary st enosis at t he anast omosis may be a P.963 P.964

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2081

13 - The Biliary Tract sequela of prev ious bile leak (11). If leakage is present , ERCP c an be perf ormed t o plac e a st ent ac ross t he point of ext rav asat ion. Remov able

plast ic int ernal st ent s are lef t ac ross t he point of leakage f or approximat ely 2 w eeks (186). Oc c asionally , biliary c ollec t ions require drainage c at het er dec ompression, and ult rasound or CT may be employ ed t o guide t he proc edure (218).

F igure 13- 51 Biliary nec rosis. A: Cont rast - enhanc ed c omput ed t omography of t he liv er af t er liv er t ransplant at ion show s poor enhanc ement of t he parenc hy ma w it h mult iple areas of low - densit y nec rosis in t he liv er periphery (ar r ow s). B: Small areas of low - densit y nec rosis (ar r ow heads) inv olv e t he biliary regions adjac ent t o t he port al v enous branc hes. Hepat ic art ery t hrombosis w as c onf irmed by Doppler ult rasound.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2082

13 - The Biliary Tract

F igure 13- 52 Biliary leak af t er liv er t ransplant at ion. A: Nonc ont rast c omput ed t omography show s a low - densit y perihepat ic c ollec t ion w it h a dense “ w at erf all” of opac if ied c ont rast (ar r ow s) f rom t he bile duc t . B: T - t ube c holangiogram depic t s a similar t rac t of dense c ont rast (ar r ow heads) ext ending f rom t he bile duc t at t he sit e of t he T - t ube insert ion. Not e t he f illing def ec t s of ret ained bile duc t st ones in t he rec ipient port ion of t he bile duc t .

Dilat at ion of t he bile duc t s af t er liv er t ransplant at ion should suggest biliary st enosis or oc c lusion. How ev er, biliary st enosis may not c reat e duc t al dilat at ion in t he t ransplant ed liv er, ev en if t here is biliary obst ruc t ion c aused by a signif ic ant st enosis (198). Ac t iv e dist ent ion of t he biliary duc t s by PT C or ERCP may det ec t a st enosis t hat is not apparent on CT or MRI (198). Biliary st enosis may result f rom duc t al injury during surgery or prolonged c old st orage prior t o t ransplant at ion (211). In c ont rast , biliary dilat at ion is not alw ay s c aused by st enosis. Dilat at ion of t he duc t also may result f rom Sphinc t er of Oddi dy sf unc t ion, possibly due t o denerv at ion of t he duc t (195). Ot her c auses of biliary dilat at ion inc lude biliary st one and sludge f ormat ion (114). St ones may f orm in t he duc t s as a result of st asis or inf ec t ion or possibly t he ef f ec t s of c y c losporin A on t he bile (168). Rarely , a muc oc ele may ext rinsic ally c ompress and obst ruc t t he c ommon duc t (54). In pat ient s t ransplant ed f or PSC, rec urrenc e of t he original disease proc ess may hav e an imaging appearanc e similar t o t he original disease w it h st ric t ures and areas of biliary dilat at ion on CT or MRCP. Bile duc t isc hemia and nec rosis is of t en sev ere and t hreat ens allograf t surv iv al. T he bile duc t s are v ery sensit iv e t o isc hemia and depend solely on hepat ic art erial blood supply (103,269). Ac ut e art erial oc c lusion c an be lif e t hreat ening and requires ret ransplant at ion. Part ial t hrombosis may result in st ric t ures or biliary nec rosis (89). Biliary nec rosis may result in bile leak or absc ess f ormat ion (93,111). Ult rasound is generally t he f irst sc reening st udy t o suggest hepat ic art erial t hrombosis by demonst rat ing dec reased art erial f low or post st enot ic w av ef orms on c olor and spec t ral Doppler imaging. T here may be irregular biliary dilat at ion w it h c ommunic at ion t o small bilomas on gray sc ale images. CT may show f oc al perf usional def ec t s if t he art erial t hrombosis is segment al (89). How ev er, t he diagnosis is usually c onf irmed w it h angiography or at surgic al explorat ion.

Living Donor Transplant Complications

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2083

13 - The Biliary Tract LDLT is a subset of liv er t ransplant at ion t hat has similar c omplic at ions t o

c adav eric t ransplant at ion w it h some spec if ic dif f erenc es. T he c omplic at ions of liv ing donor t ransplant at ion may simult aneously af f ec t t w o indiv iduals. In some c ases, t he donor c an dev elop c omplic at ions of t he proc edure and require addit ional surgery . Bile leak f rom t he resec t ed surf ac e of t he liv er in t he donor may c ause biloma f ormat ion or perit onit is (186). T he c omplic at ions in t he rec ipient are similar t o rec ipient s of c adav eric liv ers, but oc c ur more f requent ly (65). In t he rec ipient , biliary leak is t he most c ommon immediat e c omplic at ion and may oc c ur at t he liv er edge or anast omosis (65). Unlike c adav eric t ransplant s, t he biliary drainage f or LDLT is most c ommonly c reat ed as Roux- en- Y hepat ic ojejunost omy , rat her t han a duc t - duc t anast omosis, bec ause t here is a higher rat e of st enosis in adult LDLT rec ipient s using duc t - duc t biliary drainage (112). How ev er, w hen a biliary ent eric anast omosis is perf ormed, biliary st enosis at t he anast omosis is t he most c ommon c omplic at ion and may be det ec t ed as biliary dilat at ion by MRCP or ult rasound (65). One benef it of LDLT is t here is dec reased “ c old isc hemic t ime” of t he liv er bec ause t he proc edure is elec t iv e, and t his t y pe of c old injury should be minimized (67).

Biliary Complications of Radiofrequency Ablation CT is a c ommonly used f or surv eillanc e af t er radiof requenc y ablat ion (RF A) of primary or sec ondary liv er malignanc y . RF A may result in biliary injury , alt hough t his only oc c urs in approximat ely 1% of c ases (175). T he most c ommon c omplic at ion is biliary st ric t ure. In c ent ral t umor t reat ment , t he c ent ral biliary st ruc t ures may require a st ent plac ement af t er t he proc edure bec ause of t he risk of st ric t ure f ormat ion (87,157,260). Ot her report ed c omplic at ions of RF A are biliary leakage and biloma, f ist ula, and hemat obilia (175).

Assessment of Biliary Stents and Drains Migrat ion of a biliary st ent oc c urs in up t o 6% of pat ient s, and t he st ent w ill of t en pass int o t he bow el (9). T he loc at ion of a biliary st ent or drain c an be w ell depic t ed in an at y pic al loc at ion, suc h as w it hin t he small bow el (F ig. 1353). A malposit ioned st ent may remain in t he bile duc t , but it may no longer c ross a lev el of st enosis. Panc reat ic st ent migrat ion f urt her int o t he panc reas

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2084

13 - The Biliary Tract duc t may require endosc opic or open surgic al remov al (F ig. 13- 54). A largec aliber st ent or a short st ent has a higher risk of migrat ion (9).

Alt hough MRI may adequat ely show a drainage c at het er, t he spat ial resolut ion is generally bet t er f or CT . Cat het ers are of t en dense on CT but only appear as a low signal linear st ruc t ure on MRI. Also, mot ion art if ac t is more likely t o limit v isualizat ion of t he c at het er by MRI. Bile duc t drainage may help in c ases of bile leak, but drainage alone is of t en not enough if t he leakage is c aused by biliary nec rosis f rom art erial insuf f ic ienc y (269). Cat het ers c an bec ome bloc ked w it h biliary st ones or sludge. St asis of bile f low is a major c ause of c at het er obst ruc t ion. If t he c at het er is perc ut aneous, it may be exc hanged f or a new t ube t o improv e t ube f unc t ion. Int ernal biliary st ent s require ERCP or PT C f or st ent exc hange (220). Hemat obilia is a pot ent ial c omplic at ion of liv er inst rument at ion and is most c ommon af t er liv er biopsy or P.965 perc ut aneous biliary drain plac ement . T his c omplic at ion oc c urs in 2% t o 10% of c ases (68,105,129,182). T here is higher risk of hemat obilia if drain plac ement is near t he liv er hilum (41). How ev er, ult rasound guidanc e may help t o av oid t he c ent ral hepat ic v essels and reduc e t he inc idenc e of v asc ular injury (122). CT c an show biliary dilat at ion w it h c lot or a c ont rast c ollec t ion in t he duc t s or gallbladder (F ig. 13- 55) (126,155). Angiography is t he def init iv e imaging st udy , but it is inv asiv e and may det ec t injuries t hat are c linic ally self - limit ed. By angiographic assessment , t here is art erial injury in up t o 32% of biliary drainage proc edures (92,171).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2085

13 - The Biliary Tract

F igure 13- 53 Biliary st ent migrat ion. A: Comput ed t omography (CT ) image of t he liv er post –st ent plac ement show s pneumobilia (ar r ow heads), indic at ing st ent pat enc y . B: Sc out CT image demonst rat es t he biliary st ent (ar r ow s) in

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2086

13 - The Biliary Tract proper posit ion. C : Image 3 mont hs lat er show s int rahepat ic bile duc t

dilat at ion (ar r ow heads) and absent pneumobilia, suggest ing st ent dy sf unc t ion. D: Sc out CT image show s t hat t he st ent (ar r ow s) has migrat ed dist ally . (c ont inued) (c ont inued)E: Ref ormat t ed CT show s t he migrat ed st ent (ar r ow s). Not e t he biliary dilat at ion (ar r ow heads) abov e t he lev el of t he st ent and t he absenc e of pneumobilia proximal t o t he st ent .

P.966

Post–Whipple Procedure Assessment Resec t ion of panc reat ic c arc inoma of t en requires part ial panc reat ec t omy , part ial duodenec t omy , and biliary - ent eric anast omosis. Abnormal laborat ory v alues may indic at e biliary dy sf unc t ion, and should be ev aluat ed by ult rasound or MRCP. Benign biliary st ric t ures or leaks may be present as a result of t he proc edure. CT or ult rasound may det ec t a biloma as a f oc al f luid c ollec t ion near t he anast omot ic regions. Imaging c an also be used t o guide perc ut aneous drainage c at het er plac ement bec ause ERCP is of t en no longer possible in t hese P.967 pat ient s. If t here is also a biliary st enosis, t he biliary sy st em must also be persist ent ly drained t o allow healing. F ollow - up c holangiography must c onf irm healing of t he point of leakage bef ore t he biloma drainage is disc ont inued (69). In a c ase of delay ed new - onset biliary obst ruc t ion af t er Whipple proc edure, rec urrent malignanc y obst ruc t ing t he duc t s should be a c onsiderat ion.

F igure 13- 54 Panc reat ic st ent migrat ion. A, B: Axial c omput ed t omography images of t he panc reat ic t ail show t hat a st ent (ar r ow s), w hic h w as

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2087

13 - The Biliary Tract prev iously plac ed ac ross t he ampulla, has migrat ed int o t he panc reat ic t ail. Surgery w as required t o remov e t he st ent .

F igure 13- 55 Hemat obilia. CT demonst rat es high at t enuat ion c lot t hroughout t he biliary sy st em af t er a liv er biopsy .

REFERENCES 1. Aadland E, Sc hrumpf E, F ausa O, et al. Primary sc lerosing c holangit is: a long- t erm f ollow - up st udy . Sc and J Gast r oent er ol. 1987;22:655–664. 2. Abou- Saif A, Al- Kaw as F H. Complic at ions of gallst one disease: Mirizzi sy ndrome, c holec y st oc holedoc hal f ist ula, and gallst one ileus. Am J Gast r oent er ol. 2002;97:249–254. 3. Adjei ON, T amura S, Sugimura H, et al. Cont rast - enhanc ed MR imaging of int rahepat ic c holangioc arc inoma. Clin Radiol. 1995; 50:6–10. 4. Ahmed A, Cheung RC, Keef f e EB. Management of gallst ones and t heir c omplic at ions. Am F am Phy sic ian. 2000;61:1673–1680, 1687–1678. 5. Ahrendt SA, Pit t HA. Surgic al t reat ment f or primary sc lerosing c holangit is. J Hepat obiliar y Panc r eat Sur g. 1999;6:366–372. 6. Akat a D, Ozmen MM, Kay a A, et al. Radiologic al f indings of int raparenc hy mal liv er Asc aris (hepat obiliary asc ariasis). Eur Radiol. 1999;9:93–95.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2088

13 - The Biliary Tract 7. Albasini JL, Aledo VS, Dext er SP, et al. Bile leakage f ollow ing laparosc opic c holec y st ec t omy . Sur g Endosc . 1995;9:1274–1278. 8. Aldrighet t i L, Arru M, Ronzoni M, et al. Ext rahepat ic biliary st enoses af t er hepat ic art erial inf usion (HAI) of f loxuridine (F UdR) f or liv er met ast ases f rom c olorec t al c anc er. Hepat ogast r oent er ology 2001;48:1302–1307. 9. Alipert i G. Complic at ions relat ed t o diagnost ic and t herapeut ic endosc opic ret rograde c holangiopanc reat ography . Gast r oint est Endosc Clin N Am . 1996;6:379–407.

10. Alonso- Lej F , Rev er WBJ, Pessagno DJ. Congenit al c holedoc hal c y st , w it h a report of 2, and an analy sis of 94 c ases. Int Abst r Sur g. 1959;108:1–30. 11. Amet ani F , It oh K, Shibat a T , et al. Spec t rum of CT f indings in pediat ric pat ient s af t er part ial liv er t ransplant at ion. Radiogr aphic s 2001;21:53–63. 12. Anderson CM, Saloner D, T suruda JS, et al. Art if ac t s in maximumint ensit y - projec t ion display of MR angiograms. AJR Am J Roent genol. 1990;154:623–629. 13. Arai K, Kaw ai K, Kohda W, et al. Dy namic CT of ac ut e c holangit is: early inhomogeneous enhanc ement of t he liv er. AJR Am J Roent genol. 2003;181:115–118. 14. Asf ar S, Met rakos P, F ry er J, et al. An analy sis of lat e deat hs af t er liv er t ransplant at ion. T r ansplant at ion 1996;61:1377–1381. 15. Babbit t DP. Congenit al c holedoc hal c y st s: new et iologic al c onc ept based on anomalous relat ionships of t he c ommon bile duc t and panc reat ic bulb. Ann Radiol (Paris). 1969;12:231–240. 16. Bac h DB, Sat in R, Palay ew M, et al. Herniat ion and st rangulat ion of t he gallbladder t hrough t he f oramen of w inslow . AJR Am J Roent genol. 1984;142:541–542. 17. Bac kman L, Gibbs J, Lev y M, et al. Causes of lat e graf t loss af t er liv er t ransplant at ion. T r ansplant at ion 1993;55:1078–1082. 18. Barakos JA, Ralls PW, Lapin SA, et al. Cholelit hiasis: ev aluat ion w it h CT . Radiology 1987;162:415–418. 19. Bart holomew LG, Cain JC, Woolner LB, et al. Sc lerosing c holangit is: it s possible assoc iat ion w it h Riedel's st ruma and f ibrous ret roperit onit is. Report of t w o c ases. N Engl J Med. 1963;269: 8–12. 20. Bassignani MJ, F ulc her AS, Szuc s RA, et al. Use of imaging f or liv ing donor liv er t ransplant at ion. Radiogr aphic s 2001;21:39–52.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2089

13 - The Biliary Tract

21. Bec ker CD, Grossholz M, Bec ker M, et al. Choledoc holit hiasis and bile duc t st enosis: diagnost ic ac c urac y of MR c holangiopanc reat ography . Radiology 1997;205:523–530. 22. Bernard HR, Hart man T W. Complic at ions af t er laparosc opic c holec y st ec t omy . Am J Sur g. 1993;165:533–535. 23. Beut ow PC, Midkif f RB. MR imaging of t he liv er. Primary malignant neoplasms in t he adult . Magn Reson Im aging Clin N Am . 1997;5:289–318. 24. Bismut h H, Nakac he R, Diamond T . Management st rat egies in resec t ion f or hilar c holangioc arc inoma. Ann Sur g. 1992;215:31–38. 25. Blac kbourne L, Earnhardt R, Sist rom C, et al. T he sensit iv it y and role of ult rasound in t he ev aluat ion of biliary obst ruc t ion. Am Sur g. 1994;60:683–690. 26. Bort of f GA, Chen MY , Ot t DJ, et al. Gallbladder st ones: imaging and int erv ent ion. Radiogr aphic s 2000;20:751–766. 27. Broome U, Lof berg R, Veress B, et al. Primary sc lerosing c holangit is and ulc erat iv e c olit is: ev idenc e f or inc reased neoplast ic pot ent ial. Hepat ology 1995;22:1404–1408. 28. Buc kles DC, Lindor KD, Larusso NF , et al. In primary sc lerosing c holangit is, gallbladder poly ps are f requent ly malignant . Am J Gast r oent er ol. 2002;97:1138–1142. 29. Cabada Giadas T , Sarria Oc t av io de T oledo L, Mart inez- Berganza Asensio MT , et al. Helic al CT c holangiography in t he elev at ion of t he biliary t rac t : applic at ion t o t he diagnosis of c holedoc holit hiasis. Abdom Im aging. 2002;27:61–70. 30. Caldw ell SH, Hespenheide EE, Harris D, et al. Imaging and c linic al c harac t erist ic s of f oc al at rophy of segment s 2 and 3 in primary sc lerosing c holangit is. J Gast r oent er ol Hepat ol. 2001;16:220–224. 31. Calv o MM, Bujanda L, Heras I, et al. Magnet ic resonanc e c holangiography v ersus ult rasound in t he ev aluat ion of t he gallbladder. J Clin Gast r oent er ol. 2002;34:233–236. 32. Campbell WL, Pet erson MS, F ederle MP, et al. Using CT and c holangiography t o diagnose biliary t rac t c arc inoma c omplic at ing primary sc lerosing c holangit is. AJR Am J Roent genol. 2001; 177:1095–1100. 33. Caoili EM, Paulson EK, Hey neman LE, et al. Helic al CT c holangiography w it h t hree- dimensional v olume rendering using an oral biliary c ont rast agent : f easibilit y of a nov el t ec hnique. AJR Am J Roent genol. 2000;174:487–492.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2090

13 - The Biliary Tract 34. Cesari S, Liessi G, Balest reri L, et al. Ray sum rec onst ruc t ion algorit hm in MR c holangiopanc reat ography . Magn Reson Im aging. 2000;18:217–219. 35. Chamberlain RS, Blumgart LH. Hilar c holangioc arc inoma: a rev iew and c omment ary . Ann Sur g Onc ol. 2000;7:55–66. 36. Chapman RW, Arborgh BA, Rhodes JM, et al. Primary sc hlerosing c holangit is: a rev iew of it s c linic al f eat ures, c holangiography , and hepat ic hist ology . Gut 1980;21:870–877. 37. Choi BI, Y eon KM, Kim SH, et al. Caroli disease: c ent ral dot sign in CT . Radiology 1990;174:161–163. 38. Choi JW, Kim T K, Kim KW, et al. Anat omic v ariat ion in int rahepat ic bile

duc t s: an analy sis of int raoperat iv e c holangiograms in 300 c onsec ut iv e donors f or liv ing donor liv er t ransplant at ion. Kor ean J Radiol. 2003;4:85–90. 39. Coakley F V, Sc hw art z LH, Blumgart LH, et al. Complex post c holec y st ec t omy biliary disorders: preliminary experienc e w it h ev aluat ion by means of breat h- hold MR c holangiography . Radiology 1998;209:141–146. 40. Cronan JJ. US diagnosis of c holedoc holit hiasis: a reappraisal. Radiology 1986;161:133–134. 41. Crout c h KL, Gordon RL, Ring EJ, et al. Superelec t iv e art erial embolizat ion in t he liv er t ransplant rec ipient : a saf e t reat ment f or hemobilia c aused by perc ut aneous t ranshepat ic biliary drainage. Liv er T r anspl Sur g. 1996;2:118–123. 42. Csendes A, Diaz JC, Burdiles P, et al. Mirizzi sy ndrome and c holec y st obiliary f ist ula: a unif y ing c lassif ic at ion. Br J Sur g. 1989;76:1139–1143. 43. Cuenc a IJ, Mart inez del Olmo L, Perez Homs M. Helic al CT w it hout c ont rast in c holedoc holit hiasis diagnosis. Eur Radiol. 2001;11:197–201. 44. D'Alessandro A M, Kalay oglu M, Pirsc h JD, et al. Biliary t rac t c omplic at ions af t er ort hot opic liv er t ransplant at ion. T r ansplant Pr oc . 1991;23:1956. 45. Da Silv a F , Boudghene F , Lec omt e I, et al. Sonography in AIDS- relat ed c holangit is: prev alenc e and c ause of ec hogenic nodule in t he dist al end of t he c ommon bile duc t . AJR Am J Roent genol. 1993;160:1205–1207. 46. De Bac ker AI, Van den Abbeele K, De Sc hepper AM, et al. Choledoc hoc ele: diagnosis by magnet ic resonanc e imaging. Abdom Im aging. 2000;25:508–510. P.968 47. de Groen PC, Gores GJ, LaRusso NF , et al. Biliary t rac t c anc ers. N Engl J Med. 1999;341:1368–1378.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2091

13 - The Biliary Tract 48. Demart ines N, Eisner L, Sc hnabel K, et al. Ev aluat ion of magnet ic

resonanc e c holangiography in t he management of bile duc t st ones. Ar c h Sur g. 2000;135:148–152. 49. Dodd GD, 3rd, Baron RL, Oliv er JH, 3rd, et al. End- st age primary sc lerosing c holangit is: CT f indings of hepat ic morphology in 36 pat ient s. Radiology 1999;211:357–362. 50. Drane WE. Nuc lear medic ine t ec hniques f or t he liv er and biliary sy st em. Updat e f or t he 1990s. Radiol Clin Nor t h Am . 1991;29: 1129–1150. 51. Dy er RB, Gilpin JW, Zagoria RJ, et al. Vic arious c ont rast mat erial exc ret ion in pat ient s w it h ac ut e unilat eral uret eral obst ruc t ion. Radiology 1990;177:739–742. 52. Ebied O, F ederle MP, Blac har A, et al. Hepat oc ellular- c holangioc arc inoma: helic al c omput ed t omography f indings in 30 pat ient s. J Com put Assist T om ogr . 2003;27:117–124. 53. Ernst O, Asselah T , Sergent G, et al. MR c holangiography in primary sc lerosing c holangit is. AJR Am J Roent genol. 1998;171:1027–1030. 54. Ev ans RA, Raby ND, O'Grady JG, et al. Biliary c omplic at ions f ollow ing ort hot opic liv er t ransplant at ion. Clin Radiol. 1990;41: 190–194. 55. F an ZM, Y amashit a Y , Harada M, et al. Int rahepat ic c holangioc arc inoma: spin- ec ho and c ont rast - enhanc ed dy namic MR imaging. AJR Am J Roent genol. 1993;161:313–317. 56. F eng B, Song Q. Does t he c ommon bile duc t dilat e af t er c holec y st ec t omy ? Sonographic ev aluat ion in 234 pat ient s. AJR Am J Roent genol. 1995;165:859–861. 57. F ieber SS, Nanc e F C. Choledoc hal c y st and neoplasm: a c omprehensiv e rev iew of 106 c ases and present at ion of t w o original c ases. Am Sur g. 1997;63:982–987. 58. F it oz S, At asoy C. MR c holangiography in massiv e hepat obiliary asc ariasis. Ac t a Radiol. 2000;41:273–274. 59. F lum DR, Koepsell T , Heagert y P, et al. Common bile duc t injury during laparosc opic c holec y st ec t omy and t he use of int raoperat iv e c holangiography : adv erse out c ome or prev ent able error? Ar c h Sur g. 2001;136:1287–1292. 60. F ukukura Y , Hamanoue M, F ujiy oshi F , et al. Cholangioloc ellular c arc inoma of t he liv er: CT and MR f indings. J Com put Assist T om ogr . 2000;24:809–812.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2092

13 - The Biliary Tract 61. F ulc her AS, Szuc s RA, Bassignani MJ, et al. Right lobe liv ing donor liv er

t ransplant at ion: preoperat iv e ev aluat ion of t he donor w it h MR imaging. AJR Am J Roent genol. 2001;176:1483–1491. 62. F ulc her AS, T urner MA. Benign diseases of t he biliary t rac t : ev aluat ion w it h MR c holangiography . Sem in Ult r asound CT MR. 1999;20:294–303. 63. F ulc her AS, T urner MA. Pit f alls of MR c holangiopanc reat ography (MRCP). J Com put Assist T om ogr . 1998;22:845–850. 64. F ulc her AS, T urner MA, F ranklin KJ, et al. Primary sc lerosing c holangit is: ev aluat ion w it h MR c holangiography - a c ase- c ont rol st udy . Radiology 2000;215:71–80. 65. F ulc her AS, T urner MA, Ham JM. Lat e biliary c omplic at ions in right lobe liv ing donor t ransplant at ion rec ipient s: imaging f indings and t herapeut ic int erv ent ions. J Com put Assist T om ogr . 2002;26:422–427. 66. F ulc her AS, T urner MA, Sany al AJ. Case 38: Caroli disease and renal t ubular ec t asia. Radiology 2001;220:720–723. 67. Garc ia- Criado A, Gilabert R, Bargallo X, et al. Radiology in liv er t ransplant at ion. Sem in Ult r asound CT MR. 2002;23:114–129. 68. Gazzaniga GM, F aggioni A, Bondanza G, et al. Perc ut aneous t ranshepat ic biliary drainage - t w elv e y ears' experienc e. Hepat ogast r oent er ology 1990;37:517–523. 69. Gerv ais DA, F ernandez- del Cast illo C, O'Neill MJ, et al. Complic at ions af t er panc reat oduodenec t omy : imaging and imaging- guided int erv ent ional proc edures. Radiogr aphic s 2001;21:673–690. 70. Goodman ZD, Ishak KG, Langloss JM, et al. Combined hepat oc ellularc holangioc arc inoma. A hist oligic and immunohist oc hemic al st udy . Canc er 1985;55:124–135. 71. Gore RM, Miller F H, Y aghmai V. Ac quired immunodef ic ienc y sy ndrome (AIDS) of t he abdominal organs: imaging f eat ures. Sem in Ult r asound CT MR. 1998;19:175–189. 72. Gores GJ. Cholangioc arc inoma: c urrent c onc ept s and insight s. Hepat ology 2003;37:961–969. 73. Greif F , Bronst her OL, Van T hiel DH, et al. T he inc idenc e, t iming, and management of biliary t rac t c omplic at ions af t er ort hot opic liv er t ransplant at ion. Ann Sur g. 1994;219:40–45. 74. Groebli Y , Mey er JL, T sc hant z P. Choledoc hoc ele demonst rat ed by c omput ed t omographic c holangiography : report of a c ase. Sur g T oday . 2000;30:272–276.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2093

13 - The Biliary Tract 75. Guibaud L, Bret PM, Reinhold C, et al. Bile duc t obst ruc t ion and c holedoc holit hiasis: diagnosis w it h MR c holangiography . Radiology 1995;197:109–115. 76. Gut hrie JA, Ward J, Robinson PJ. Hilar c holangioc arc inomas: T 2- w eight ed spin- ec ho and gadolinium- enhanc ed F LASH MR imaging. Radiology 1996;201:347–351.

77. Guy F , Cognet F , Dranssart M, et al. Caroli's disease: magnet ic resonanc e imaging f eat ures. Eur Radiol. 2002;12:2730–2736. 78. Hakansson K, Leander P, Ekberg O, et al. MR imaging of upper abdomen f ollow ing c holec y st ec t omy . Normal and abnormal f indings. Ac t a Radiol. 2001;42:181–186. 79. Hall- Craggs MA, Allen CE, Ow ens CM, et al. MR c holangiography : c linic al ev aluat ion in 40 c ases. Radiology 1993;189:423–427. 80. Han JK, Choi BI, Kim AY , et al. Cholangioc arc inoma: pic t orial essay of CT and c holangiographic f indings. Radiogr aphic s 2002;22: 173–187. 81. Han SJ, Hw ang EH, Chung KS, et al. Ac quired c holedoc hal c y st f rom anomalous panc reat obiliary duc t union. J Pediat r Sur g. 1997;32:1735–1738. 82. Hanau LH, St eigbigel NH. Ac ut e (asc ending) c holangit is. Inf ec t Dis Clin Nor t h Am . 2000;14:521–546. 83. Harris HW, Kumw enda ZL, Sheen- Chen SM, et al. Rec urrent py ogenic c holangit is. Am J Sur g. 1998;176:34–37. 84. Harrison PM. Diagnosis of primary sc lerosing c holangit is. J Hepat obiliar y Panc r eat Sur g. 1999;6:356–360. 85. Hart man EM, Barish MA. MR c holangiography . Magn Reson Im aging Clin N Am . 2001;9:841–855. 86. Hasegaw a K, Kubot a K, Komat su Y , et al. Mass- f orming inf lammat ory periduc t al f ibrosis mimic king hilar bile duc t c arc inoma. Hepat ogast r oent er ology 2000;47:1230–1233. 87. Hav lik R. Radiof requenc y t hermal ablat ion in liv er t umours. In: Annual Cour se in Hepat obiliar y and Panc r eat ic Sur ger y , Hammersmit h Hospit al. London, 1999. 88. Helling T S, St robac h RS. T he surgic al c hallenge of papillary neoplasia of t he biliary t rac t . Liv er T r anspl Sur g. 1996;2:290–298. 89. Heneghan MA, Sy lv est re PB. Cholest at ic diseases of liv er t ransplant at ion. Sem in Gast r oint est Dis. 2001;12:133–147. 90. Hennig J, Nauert h A, F riedburg H. RARE imaging: a f ast imaging met hod f or c linic al MR. Magn Reson Med. 1986;3:823–833.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2094

13 - The Biliary Tract 91. Hirohashi S, Hirohashi R, Uc hida H, et al. MR c holangiopanc reat ography and MR urography : improv ed enhanc ement w it h a negat iv e oral c ont rast agent . Radiology 1997;203:281–285. 92. Hoev els J, Nilsson U. Int rahepat ic v asc ular lesions f ollow ing nonsurgic al perc ut aneous t ranshepat ic bile duc t int ubat ion. Gast r oint est Radiol. 1980;5:127–135.

93. Hof f er F A, T eele RL, Lillehei CW, et al. Inf ec t ed bilomas and hepat ic art ery t hrombosis in inf ant rec ipient s of liv er t ransplant s. Int erv ent ional radiology and medic al t herapy as an alt ernat iv e t o ret ransplant at ion. Radiology 1988;169:435–438. 94. Holzknec ht N, Gauger J, Sac kmann M, et al. Breat h- hold MR c holangiography w it h snapshot t ec hniques: prospec t iv e c omparison w it h endosc opic ret rograde c holangiography . Radiology 1998;206:657–664. 95. Hopper KD, Weingast G, Rudikof f J, et al. Vic arious exc ret ion of w at ersoluble c ont rast media int o t he gallbladder in pat ient s w it h normal serum c reat inine. Inv est Radiol. 1988;23:604–608. 96. How ard T J, Chin AC, St reib EW, et al. Value of helic al c omput ed t omography , angiography , and endosc opic ult rasound in det ermining resec t abilit y of periampullary c arc inoma. Am J Sur g. 1997;174:237–241. 97. Hunt DR. Common bile duc t st ones in non- dilat ed bile duc t s? An ult rasound st udy . Aust r alas Radiol. 1996;40:221–222. 98. Hw ang CM, Kim T K, Ha HK, et al. Biliary asc ariasis: MR c holangiography f indings in t w o c ases. Kor ean J Radiol. 2001;2:175–178. 99. Hw ang JI, Chou Y H, T say SH, et al. Radiologic and pat hologic c orrelat ion of adenomy omat osis of t he gallbladder. Abdom Im aging. 1998;23:73–77. 100. Imamura H, Makuuc hi M, Sakamot o Y , et al. Anat omic al key s and pit f alls in liv ing donor liv er t ransplant at ion. J Hepat obiliar y Panc r eat Sur g. 2000;7:380–394. 101. Irie H, Honda H, Kuroiw a T , et al. Pit f alls in MR c holangiopanc reat ographic int erpret at ion. Radiogr aphic s 2001;21:23–37. P.969 102. It o K, Mit c hell DG, Out w at er EK, et al. Primary sc lerosing c holangit is: MR imaging f eat ures. AJR Am J Roent genol. 1999;172:1527–1533. 103. It o K, Siegelman ES, St olpen AH, et al. MR imaging of c omplic at ions af t er liv er t ransplant at ion. AJR Am J Roent genol. 2000;175: 1145–1149.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2095

13 - The Biliary Tract 104. Jaisw al M, LaRusso NF , Burgart LJ, et al. Inf lammat ory c y t okines induc e DNA damage and inhibit DNA repair in c holangioc arc inoma c ells by a nit ric oxide- dependent mec hanism. Canc er Res. 2000;60:184–190. 105. Jeng KS, Oht a I, Y ang F S. Reappraisal of t he sy st emat ic management of c omplic at ed hepat olit hiasis w it h bilat eral int rahepat ic biliary st ric t ures. Ar c h Sur g. 1996;131:141–147. 106. Johnson GK, Geenen JE, Venu RP, et al. Endosc opic t reat ment of biliary

t rac t st ric t ures in sc lerosing c holangit is: a larger series and rec ommendat ions f or t reat ment . Gast r oint est Endosc . 1991;37:38–43. 107. Johnson PT , Heat h DG, Hof mann LV, et al. Mult idet ec t or- row c omput ed t omography w it h t hree- dimensional v olume rendering of panc reat ic c anc er: a c omplet e preoperat iv e st aging t ool using c omput ed t omography angiography and v olume- rendered c holangiopanc reat ography . J Com put Assist T om ogr . 2003;27:347–353. 108. Kaim A, St einke K, F rank M, et al. Diamet er of t he c ommon bile duc t in t he elderly pat ient : measurement by ult rasound. Eur Radiol. 1998;8:1413–1415. 109. Kalloo AN, Kant sev oy SV. Gallst ones and biliary disease. Pr im Car e. 2001;28:591–606. 110. Kaplan AA, Pagonini EP, Bosc h JP. Ef f ec t of t he dialy sis membrane in ac ut e renal f ailure. N Engl J Med. 1995;332:961–962. 111. Kaplan SB, Zajko AB, Koneru B. Hepat ic bilomas due t o hepat ic art ery t hrombosis in liv er t ransplant rec ipient s: perc ut aneous drainage and c linic al out c ome. Radiology 1990;174(3 Pt 2):1031–1035. 112. Kaw ac hi S, Shimazu M, Wakabay ashi G, et al. Biliary c omplic at ions in adult liv ing donor liv er t ransplant at ion w it h duc t - t o- duc t hepat ic oc holedoc host omy or Roux- en- Y hepat ic ojejunost omy biliary rec onst ruc t ion. Sur ger y 2002;132:48–56. 113. Kelekis NL, Semelka RC. MR imaging of t he gallbladder. T op Magn Reson Im aging. 1996;8:312–320. 114. Keogan MT , Mc Dermot t VG, Pric e SK, et al. T he role of imaging in t he diagnosis and management of biliary c omplic at ions af t er liv er t ransplant at ion. AJR Am J Roent genol. 1999;173:215–219. 115. Keogan MT , Seabourn JT , Paulson EK, et al. Cont rast - enhanc ed CT of int rahepat ic and hilar c holangioc arc inoma: delay t ime f or opt imal imaging. AJR Am J Roent genol. 1997;169:1493–1499.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2096

13 - The Biliary Tract 116. Khalid T R, Casillas VJ, Mont alv o BM, et al. Using MR c holangiopanc reat ography t o ev aluat e iat rogenic bile duc t injury . AJR Am J Roent genol. 2001;177:1347–1352. 117. Khan SA, Dav idson BR, Goldin R, et al. Guidelines f or t he diagnosis and t reat ment of c holangioc arc inoma: c onsensus doc ument . Gut 2002;51 (Suppl VI):v i1–v i9.

118. Kim T K, Choi BI, Han JK, et al. Peripheral c holangioc arc inoma of t he liv er: t w o- phase spiral CT f indings. Radiology 1997;204:539–543. 119. Kim T K, Kim BS, Kim JH, et al. Diagnosis of int rahepat ic st ones: superiorit y of MR c holangiopanc reat ography ov er endosc opic ret rograde c holangiopanc reat ography . AJR Am J Roent genol. 2002;179:429–434. 120. Kim Y H. Panc reat it is in assoc iat ion w it h Clonorc his sinensis inf est at ion: CT ev aluat ion. AJR Am J Roent genol. 1999;172: 1293–1296. 121. Kluge R, Sc hmidt F , Cac a K, et al. Posit ron emission t omography w it h [(18)F ]f luoro- 2- deoxy - D- gluc ose f or diagnosis and st aging of bile duc t c anc er. Hepat ology 2001;33:1029–1035. 122. Koit o K, Namieno T , Nagakaw a T , et al. Perc ut aneous t ranshepat ic biliary drainage using c olor Doppler ult rasonography . J Ult r asound Med. 1996;15:203–206. 123. Kondo H, Kanemat su M, Shirat ori Y , et al. Pot ent ial pit f all of MR c holangiopanc reat ography : right hepat ic art erial impression of t he c ommon hepat ic duc t . J Com put Assist T om ogr . 1999;23:60–62. 124. Kozarek R, Gannan R, Baerg R, et al. Bile leak af t er laparosc opic c holec y st ec t omy . Diagnost ic and t herapeut ic applic at ion of endosc opic ret rograde c holangiopanc reat ography . Ar c h Int er n Med. 1992;152:1040–1043. 125. Krishnani N, Shukla S, Jain M, et al. F ine needle aspirat ion c y t ology in xant hogranulomat ous c holec y st it is, gallbladder adenoc arc inoma and c oexist ent lesions. Ac t a Cy t ol. 2000;44:508–514. 126. Krudy AG, Doppman JL, Bissonet t e MB, et al. Hemobilia: c omput ed t omographic diagnosis. Radiology 1983;148:785–789. 127. Kubo S, Hamba H, Hirohashi K, et al. Magnet ic Resonanc e c holangiography in hepat olit hiasis. Am J Gast r oent er ol. 1997;92:629–632. 128. Kubot a T , T homson A, Cloust on AD, et al. Clinic opat hologic f indings of rec urrent primary sc lerosing c holangit is af t er ort hot opic liv er t ransplant at ion. J Hepat obiliar y Panc r eat Sur g. 1999; 6:377–381.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2097

13 - The Biliary Tract 129. L'Hermine C, Ernst O, Delemazure O, et al. Art erial c omplic at ions of perc ut aneous t ranshepat ic biliary drainage. Car diov asc Int er v ent Radiol. 1996;19:160–164. 130. Ladas SD, Kat sogridakis I, T assios P, et al. Choledoc hoc ele, and ov erlooked diagnosis: report of 15 c ases and rev iew of 56 published report s f rom 1984 t o 1992. Endosc opy 1995;27:233–239. 131. Laghi A, Pav one P, Cat alano C, et al. MR c holangiography of lat e biliary c omplic at ions af t er liv er t ransplant at ion. AJR Am J Roent genol. 1999;172:1541–1546. 132. Lamah M, Karanjia ND, Dic kson GH. Anat omic al v ariat ions of t he ext rahepat ic biliary t ree: rev iew of t he w orld lit erat ure. Clin Anat . 2001;14:167–172. 133. Lee JW, Han JK, Kim T K, et al. CT f eat ures of int raduc t al int rahepat ic c holangioc arc inoma. AJR Am J Roent genol. 2000;175:721–725. 134. Lee SB, Ry u KH, Ry u JK, et al. Ac ut e ac alc ulous c holec y st it is assoc iat ed

w it h c holec y st oduodenal f ist ula and duodenal bleeding. A c ase report . Kor ean J Int er n Med. 2003;18:109–114. 135. Lee SS, Kim MH, Lee SK, et al. MR c holangiography v ersus c holangiosc opy f or ev aluat ion of longit udinal ext ension of bilar c holangioc arc inoma. Gast r oint est Endosc . 2002;56:25–32. 136. Lee WJ, Lim HK, Jang KM, et al. Radiologic spec t rum of c holangioc arc inoma: emphasis on unusual manif est at ions and dif f erent ial diagnoses. Radiogr aphic s 2001;21:S97–S116. 137. Lee Y M, Kaplan MM. Medic al t reat ment of primary sc lerosing c holangit is. J Hepat obiliar y Panc r eat Sur g. 1999;6:361–365. 138. Lee Y M, Kaplan MM. Primary sc lerosing c holangit is. N Engl J Med. 1995;332:924–933. 139. Lerut J, Gordon RD, Iw at suki S, et al. Biliary t rac t c omplic at ions in human ort hot opic liv er t ransplant at ion. T r ansplant at ion 1987; 43:47–51. 140. Lev y AD, Murakat a LA, Rohrmann CA, Jr. Gallbladder c arc inoma: radiologic - pat hologic c orrelat ion. Radiogr aphic s 2001;21:295–314; quest ionnaire, 549–255. 141. Lev y AD, Rohrmann CAJ, Murakat a LA, et al. Caroli's disease: radiologic spec t rum w it h pat hologic c orrelat ion. AJR Am J Roent genol. 2002;179:1053–1057. 142. Liddell RM, Baron RL, Ekst rom JE, et al. Normal int rahepat ic bile duc t s: CT depic t ion. Radiology 1990;176:633–635.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2098

13 - The Biliary Tract

143. Lillemoe KD, Pit t HA, Cameron JL. Current management of benign bile duc t st ric t ures. Adv Sur g. 1992;25:119–174. 144. Lim JH. Orient al c holangiohepat it is: pat hologic , c linic al, and radiologic f eat ures. AJR Am J Roent genol. 1991;157:1–8. 145. Lim JH, Ko Y T , Lee DH, et al. Orient al c holangiohepat it is: sonographic f indings in 48 c ases. AJR Am J Roent genol. 1990;155: 511–514. 146. Lin EC, Kuni CC. Radionuc lide imaging of hepat ic and biliary disease. Sem in Liv er Dis. 2001;21:179–194. 147. Liu T H, Consort i ET , Kaw ashima A, et al. T he ef f ic ac y of magnet ic resonanc e c holangiography f or t he ev aluat ion of pat ient s w it h suspec t ed c holedoc holit hiasis bef ore laparosc opic c holec y st ec t omy . Am J Sur g. 1999;178:480–484. 148. Lo CM, F an ST , Liu CL, et al. Adult - t o- adult liv ing donor liv er t ransplant at ion using ext ended right lobe graf t s. Ann Sur g. 1997;226:261–270. 149. Lomas DJ, Bearc rof t PW, Gimson AE. MR c holangiopanc reat ography : prospec t iv e c omparison of a breat h- hold 2D projec t ion t ec hnique w it h diagnost ic ERCP. Eur Radiol. 1999;9:1411–1417. 150. Lomas DJ, Gimson A. Magnet ic resonanc e c holangiopanc reat ography . Hosp Med. 2000;61:395–399. 151. Loud PA, Semelka RC, Ket t rit z U, et al. MRI of ac ut e c holec y st it is: c omparison w it h t he normal gallbladder and ot her ent it ies. Magn Reson Im aging. 1996;14:349–355. 152. Loy er EM, Chin H, DuBrow RA, et al. Hepat oc ellular c arc inoma and int rahepat ic peripheral c holangioc arc inoma: enhanc ement pat t erns w it h quadruple phase helic al CT —a c omparat iv e st udy . Radiology 1999;212:866–875. 153. Lubbers EJ. Mirizzi sy ndrome. Wor ld J Sur g. 1983;7:780–785. 154. Luc as WB, Chut t ani R. Pat hophy siology and c urrent c onc ept s in t he diagnosis of obst ruc t iv e jaundic e. Gast r oent er ologist 1995;3:105–118. P.970 155. Lut t er DR, Berger ML. Diagnosis of nont raumat ic hemat obilia by c omput erized t omography of t he abdomen. Am J Gast r oent er ol. 1988;83:329–330. 156. Ma KF , Iu PP, Chau LF , et al. Clinic al and radiologic al f eat ures of biliary papillomat osis. Aust r alas Radiol. 2000;44:169–173.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2099

13 - The Biliary Tract 157. Mac hi J, Oishi AJ, Morioka WK, et al. Radiof requenc y t hermal ablat ion of

sy nc hronous met ast ic liv er t umors c an be perf ormed saf ely in c onjunc t ion w it h c olorec t al c anc er resec t ion. Canc er J. 2000;6:S344–350. 158. Magnuson T H, Bender JS, Dunc an MD, et al. Ut ilit y of magnet ic resonanc e c holangiography in t he ev aluat ion of biliary obst ruc t ion. J Am Coll Sur g. 1999;189:63–71; disc ussion 71–62. 159. Manf redi R, Cost amagna G, Brizi MG, et al. Sev ere c hronic panc reat it is v ersus suspec t ed panc reat ic disease: dy namic MR c holangiopanc reat ography af t er sec ret in st imulat ion. Radiology 2000;214:849–855. 160. Manf redi R, Cost amagna G, Brizi MG, et al. Panc reas div isum and “ sant orinic ele” : diagnosis w it h dy namic MR c holangiopanc reat ography w it h sec ret in st imulat ion. Radiology 2000;217: 403–408. 161. Marc os A, F isher RA, Ham JM, et al. Right lope liv ing donor liv er t ransplant at ion. T r ansplant at ion 1999;68:798–803. 162. Mart inez A, Bona X, Velasc o M, et al. Diagnost ic ac c urac y of ult rasound in ac ut e c holec y st it is. Gast r oint est Radiol. 1986;11:334–338. 163. Marzio L, Innoc ent i P, Genov esi N, et al. Role of oral c holec y st ography , real- t ime ult rasound, and CT in ev aluat ion of gallst ones and gallbladder f unc t ion. Gast r oint est Radiol. 1992;17:257–261. 164. Maset t i R, Ant inori A, Coppola R, et al. Choledoc hoc ele: c hanging t rends in diagnosis and management . Sur g T oday . 1996;26: 281–285. 165. Mat os C, Met ens T , Dev iere J, et al. Panc reas div isum: Ev aluat ion w it h sec ret in- enhanc ed magnet ic resonanc e c holangiopanc reat ography . Gast r oint est Endosc . 2001;53:728–733. 166. Mat os C, Met ens T , Dev iere J, et al. Panc reat ic Duc t : Morphologic and F unc t ional ev aluat ion w it h dy namic MR panc reat ography af t er sec ret in st imulat ion. Radiology 1997;203:435–441. 167. Meht a SN, Reinhold C, Barkun AN. Magnet ic resonanc e c holangiopanc reat ography . Gast r oint est Endosc Clin N Am . 1997;7: 247–270. 168. Milas M, Ric ket t s RR, Amerson JR, et al. Management of biliary t rac t st ones in heart t ransplant pat ient s. Ann Sur g. 1996;223:747–756. 169. Miller F H, Gore RM, Nemc ek AAJ, et al. Panc reat ic obiliary manif est at ions of AIDS. AJR Am J Roent genol. 1996;166:1269–1274. 170. Miller WJ, Sec ht in AG, Campbell WL, et al. Imaging f indings in Caroli's disease. AJR Am J Roent genol. 1995;165:333–337.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2100

13 - The Biliary Tract 171. Monden M, Okamura J, Kobay ashi N, et al. Hemobilia af t er perc ut aneous t ranshepat ic biliary drainage. Ar c h Sur g. 1980;115:161–164. 172. Monroe SE. Congenit al absenc e of t he gallblader: a st at ist ic al st udy . J Int Coll Sur g. 1959;32:369–373. 173. Mort ele KJ, Ros PR. Cy st ic f oc al liv er lesions in t he adult : dif f erent ial CT and MR imaging f eat ures. Radiogr aphic s 2001;21:895–910. 174. Moser MA, Wall WJ. Management of biliary problems af t er liv er t ransplant at ion. Liv er T r anspl. 2001;7:S46–S52. 175. Mulier S, Mulier P, Ni Y , et al. Complic at ions of radiof requenc y c oagulat ion of liv er t umours. Br J Sur g. 2002;89:1206–1222. 176. My ers RP, Shaf f er EA, Bec k PL. Gallbladder poly ps: epidemiology , nat ural hist ory and management . Can J Gast r oent er ol. 2002;16:187–194. 177. Nakanuma Y , Harada K, Kat ay anagi K, et al. Def init ion and pat hology of primary sc lerosing c holangit is. J Hepat obiliar y Panc r eat Sur g. 1999;6:333–342. 178. Naray anan Menon KV, Wiesner R. Et iology and nat ural hist ory of primary sc lerosing c holangit is. J Hepat obiliar y Panc r eat Sur g. 1999;6:343–351.

179. Neit lic h JD, T opazian M, Smit h RC, et al. Det ec t ion of c holedoc holit hiasis: c omparison of unenhanc ed helic al CT and endosc opic ret rograde c holangiopanc reat ography . Radiology 1997;203: 753–757. 180. Nghiem HV. Imaging of hepat ic t ransplant at ion. Radiol Clin Nor t h Am . 1998;36:429–443. 181. Nghiem HV, T ran K, Wint er T C III, et al. Imaging of c omplic at ions in liv er t ransplant at ion. Radiogr aphic s 1996;16:825–840. 182. Nilsson U, Ev ander A, Ihse I, et al. Perc ut aneous t ranshepat ic c holangiography and drainage. Risks and c omplic at ions. Ac t a Radiol Diagn (St oc kh). 1983;24:433–439. 183. Nino- Murc ia M, Jef f rey RB, Jr., Beaulieu CF , et al. Mult idet ec t or CT of t he panc reas and bile duc t sy st em: v alue of c urv ed planar ref ormat ions. AJR Am J Roent genol. 2001;176:689–693. 184. Oria HE. Pit f alls in t he diagnosis of gallbladder disease in c linic ally sev ere obesit y . Obes Sur g. 1998;8:444–451. 185. Ort ega D, Burns PN, Hope Simpson D, et al. T issue harmonic imaging: is it a benef it f or bile duc t sonography ? AJR Am J Roent genol. 2001;176:653–659. 186. Ost rof f JW. Post - t ransplant biliary problems. Gast r oint est Endosc Clin N Am . 2001;11:163–183.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2101

13 - The Biliary Tract 187. Park J, T adloc k L, Gores GJ, et al. Inhibit ion of int erleukin 6- mediat ed mit ogen- ac t iv at ed prot ein kinase ac t iv at ion at t enuat es grow t h of a c holangioc arc inoma c ell line. Hepat ology 1999;30: 1128–1133. 188. Park MS, Y u JS, Kim Y H, et al. Ac ut e c holec y st it is: c omparison of MR c holangiography and US. Radiology 1998;209:781–785. 189. Parra JA, Ac inas O, Bueno J, et al. Xant hogranulomat ous c holec y st it is: c linic al, sonographic , and CT f indings in 26 pat ient s. AJR Am J Roent genol. 2000;174:979–983. 190. Pat el T . Inc reasing inc idenc e and mort alit y of primary int rahepat ic c holangioc arc inoma in t he Unit ed St at es. Hepat ology 2001;33:1353–1357. 191. Perret RS, Sloop GD, Borne JA. Common bile duc t measurement s in an elderly populat ion. J Ult r asound Med. 2000;19:727–730. 192. Pic khardt PJ, F riedland JA, Hruza DS, et al. CT , MR c holangiopanc reat ography , and endosc opy f indings in Bouv eret 's Sy ndrome. AJR Am J Roent genol. 2003;180:1033–1035. 193. Pic kut h D, Spielmann RP. Det ec t ion of c holedoc holit hiasis: c omparison of unenhanc ed spiral CT , US, and ERCP. Hepat ogast r oent er ology 2000;47:1514–1517. 194. Ponsioen CY , Vrouenraet s SME, Praw irodirdjo W, et al. Nat ural hist ory of primary sc lerosing c holangit is and prognost ic v alue of c holangiography in a Dut c h populat ion. Gut 2002;51: 562–566.

195. Poray ko MK, Kondo M, St eers JL. Liv er t ransplant at ion: lat e c omplic at ions of t he biliary t rac t and t heir management . Sem in Liv er Dis. 1995;15:139–155. 196. Prasad SR, Sahani D, Saini S. Clinic al applic at ions of magnet ic resonanc e c holangiopanc reat ography . J Clin Gast r oent er ol. 2001;33: 362–366. 197. Puri SK, Gupt a P, Panigrahi P, et al. Ult rasonographic ev aluat ion of c ommon duc t diamet er in pre and post c holec y st ec t omy pat ient s. T r op Gast r oent er ol. 2001;22:23–24. 198. Quiroga S, Sebast ia MC, Margarit C, et al. Complic at ions of ort hot opic liv er t ransplant at ion: spec t rum of f indings w it h helic al CT . Radiogr aphic s 2001;21:1085–1102. 199. Rabie ME, Al- Humay ed SM, Hosni MH, et al. Choledoc hoc ele: t he disput ed origin. Int Sur g. 2002;87:221–225. 200. Ralls PW, Collet t i PM, Lapin SA, et al. Real- t ime sonography in suspec t ed ac ut e c holec y st it is. Prospec t iv e ev aluat ion of primary and sec ondary signs. Radiology 1985;155:767–771.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2102

13 - The Biliary Tract 201. Redv anly RD, Nelson RC, St ieber AC, et al. Imaging in t he preoperat iv e ev aluat ion of adult liv er t ransplant c andidat es: goals, merit s of v arious

proc edures, and rec ommendat ions. AJR Am J Roent genol. 1995;164:611–617. 202. Regan F , Sc haef er DC, Smit h DP, et al. T he diagnost ic ut ilit y of HAST E MRI in t he ev aluat ion of ac ut e c holec y st it is. Half - F ourier ac quisit ion singleshot t urbo SE. J Com put Assist T om ogr . 1998; 22:638–642. 203. Reinhold C, Bret PM. Current St at us of MR Cholangiopanc reat ography . AJR Am J Roent genol. 1996;166:1285–1295. 204. Rizzo RJ, Szuc s RA, T urner MA. Congenit al abnormalit ies of t he panc reas and biliary t ree in adult s. Radiogr aphic s. 1995;15: 49–68. 205. Robinson EK, Lee JE, Low y AM, et al. Reoperat iv e panc reat ic oduodenec t omy f or periampullary c arc inoma. Am J Sur g. 1996; 172:432–438. 206. Romano AJ, v an Sonnenberg E, Casola G, et al. Gallbladder and bile duc t abnormalit ies in AIDS: sonographic f indings in eight pat ient s. AJR Am J Roent genol. 1988;150:123–127. 207. Rosen CB, Nagorney DM, Wiesner RH, et al. Cholangioc arc inoma c omplic at ing primary sc hlerosing c holangit is. Ann Sur g. 1991;213:21–25. 208. Rosen HR, Shac klet on CR, Mart in P. Indic at ions f or and t iming of liv er t ransplant at ion. Med Clin Nor t h Am . 1996;80:1069–1102. P.971 209. Rossi G, Luc ianet t i A, Gridelli B, et al. Biliary t rac t c omplic at ions in 224 ort hot opic liv er t ransplant at ions. T r ansplant Pr oc . 1994; 26:3626–3628. 210. Rumalla A, Pet ersen BT . Diagnosis and t herapy of biliary t rac t malignanc y . Sem in Gast r oint est Dis. 2000;11:168–173. 211. Sanc hez- Urdazpal L, St eriof f S, Janes C, et al. Inc reased bile duc t c omplic at ions in ABO inc ompat ible liv er t ransplant rec ipient s. T r ansplant Pr oc . 1991;23(1 Pt 2):1440–1441. 212. Sc hroeder T , Malago M, Debat in JF , et al. Mult idet ec t or c omput ed t omographic c holangiography in t he ev aluat ion of pot ent ial liv ing liv er donors. T r ansplant at ion 2002;73:1972–1973. 213. Sela- Herman S, Sc harsc hmidt BF . Choledoc hal c y st , a disease f or all ages. Lanc et 1996;347:779. 214. Semelka RC, Shoenut JP, Koroeker MA, et al. Bile duc t disease: prospec t iv e c omparison of ERCP, CT , and f at suppression MRI. Gast r oint est Endosc . 1992;17:347–352.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2103

13 - The Biliary Tract 215. Sermon A, Himpens J, Leman G. Sy mpt omat ic adenomy omat osis of t he gallbladder- report of a c ase. Ac t a Chir Belg. 2003; 103:225–229. 216. Shaf f er EA. Gallbladder sludge: w hat is it s c linic al signif ic anc e? Cur r Gast r oent er ol Rep. 2001;3:166–173. 217. Shaw MJ, Dorsher PJ, Vennes JA. Cy st ic duc t anat omy : an endosc opic perspec t iv e. Am J Gast r oent er ol. 1993;88:2102–2106. 218. Sherman S, Jamidar P, Shaked A, et al. Biliary t rac t c omplic at ions af t er ort hot opic liv er t ransplant at ion. Endosc opic approac h t o diagnosis and t herapy . T r ansplant at ion 1995;60:467–470. 219. Shoup M, Hodul P, Aranha GV, et al. Def ining a role f or endosc opic ult rasound in st aging periampullary t umors. Am J Sur g. 2000;179:453–456. 220. Shrest ha R, Lasc h H. Endosc opic t herapy f or biliary t rac t disease bef ore ort hot opic liv er t ransplant at ion. Gast r oint est Endosc Clin N Am . 2001;11:45–64. 221. Simeone JF , Brink JA, Mueller PR, et al. T he sonographic diagnosis of ac ut e gangrenous c holec y st it is: import anc e of t he Murphy sign. AJR Am J Roent genol. 1989;152:289–290.

222. Smit h F J, Mat hieson JR, Cooperberg PL. Abdominal Abnormalit ies in AIDS: det ec t ion at US in a large populat ion. Radiology 1994;192:691–695. 223. Sons HU, Borc hard F , Joel BS. Carc inoma of t he gallbladder: aut opsy f indings in 287 c ases and rev iew of t he lit erat ure. J Sur g Onc ol. 1985;28:199–206. 224. Soong T C, Lee RC, Cheng HC, et al. Dy namic MR imaging of hepat olit hiasis. Abdom Im aging. 1998;23:515–519. 225. Soper NJ, F ly e MW, Brunt LM, et al. Diagnosis and management of biliary c omplic at ions of laparosc opic c holec y st ec t omy . Am J Sur g. 1993;165:663–669. 226. Sot o JA, Barish MA, Alv arez O, et al. Det ec t ion of c holedoc holit hiasis w it h MR c holangiography : c omparison of t hree- dimensional f ast spin- ec ho and single- and mult isec t ion half - F ourier rapid ac quisit ion w it h relaxat ion enhanc ement sequenc es. Radiology 2000;215:737–745. 227. Sot o JA, Barish MA, Alv arez O, et al. Det ec t ion of c holedoc holit hiasis w it h MR c holangiography : c omparison of t hree- dimensional f ast spin- ec ho and single- and mult isec t ion half - f ourier rapid ac quisit ion w it h relaxat ion enhanc ement sequenc es. Radiology 2000;215:737–745.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2104

13 - The Biliary Tract 228. Sot o JA, Barish MA, Y uc el EK, et al. MR Cholangiopanc reat ography : f indings on 3D f ast spin- ec ho imaging. AJR Am J Roent genol. 1995;165:1397–1401. 229. Soy er P, Bluemke A, Sibert A, et al. MR imaging of int rahepat ic c holangioc arc inoma. Abdom Im aging. 1995;20:126–130. 230. Sparw asser C, Krupienski M, Radomsky J, et al. Gallbladder met ast asis of renal c ell c arc inoma. A c ase report and rev iew of t he lit erat ure. Ur ol Int . 1997;58:257–258. 231. St ephen AE, Berger DL. Carc inoma in t he porc elain gallbladder: a relat ionship rev isit ed. Sur ger y 2001;129:699–703. 232. St rat t a RJ, Wood RP, Langnas AN, et al. Diagnosis and t reat ment of biliary t rac t c omplic at ions af t er ort hot opic liv er t ransplant at ion. Sur ger y 1989;106:675–683. 233. St razzabosc o M, Spirli C, Okolic sany i L. Pat hophy siology of t he int rahepat ic biliary epit helium. J Gast r oent er ol Hepat ol. 2000;15: 244–253. 234. Sugiy ama M, Haradome H, T akahara T , et al. Anomalous panc reat ic obiliary junc t ion show n on mult idet ec t or CT . AJR Am J Roent genol. 2003;180:173–175. 235. T akahashi M, Saida Y , It ai Y , et al. Reev aluat ion of spiral CT c holangiography : basic c onsiderat ions and reliabilit y f or det ec t ing c holedoc holit hiasis in 80 pat ient s. J Com put Assist T om ogr . 2000;24:859–865. 236. T akay ama T , Makuuc hi M, Kaw asaki S, et al. Out f low Y - Rec onst ruc t ion f or Liv ing Relat ed Part ial Hepat ic T ransplant at ion. J Am Coll Sur g. 1994;179:227–229. 237. T aner CB, Nagorney DM, Donohue JH. Surgic al t reat ment of gallbladder c anc er. J Gast r oint est Sur g. 2004;8:83–89. 238. T eef ey SA, Baron RL, Rohrmann CA, et al. Sc lerosing c holangit is: CT f indings. Radiology 1988;169:635–639.

239. T eef ey SA, Baron RL, Sc hult e SJ, et al. Pat t erns of int rahepat ic bile duc t dilat at ion at CT : c orrelat ion w it h obst ruc t iv e disease proc esses. Radiology 1992;182:139–142. 240. T illic h M, Misc hinger HJ, Preisegger KH, et al. Mult iphasic helic al CT in diagnosis and st aging of hilar c holangioc arc inoma. AJR Am J Roent genol. 1998;171:651–658. 241. T odani T , Wat anabe Y , Narusue M, et al. Congenit al bile duc t c y st s: Classif ic at ion, operat iv e proc edures, and rev iew of t hirt y - sev en c ases

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2105

13 - The Biliary Tract inc luding c anc er arising f rom c holedoc hal c y st . Am J Sur g. 1977;134:263–269. 242. T orok N, Gores GJ. Cholangioc arc inoma. Sem in Gast r oint est Dis. 2001;12:125–132. 243. T rot man BW, Pet rella EJ, Solow ay RD, et al. Ev aluat ion of radiographic luc enc y or opaqueness of gallst ones as a means of ident if y ing c holest erol or pigment st ones. Gast r oent er ology 1975; 68:1563–1566. 244. Valls C, Guma A, Puig I, et al. Int rahepat ic peripheral c holangioc arc inoma: CT ev aluat ion. Abdom Im aging. 2000;25:490–496. 245. v an Milligen de Wit AW, Van Dev ent er SJ, T y t gat GN. Immunogenet ic aspec t s of primary sc lerosing c holangit is: implic at ions f or t herapeut ic st rat egies. Am J Gast r oent er ol. 1995;90:893–900. 246. Varghese JC, F arrell MA, Court ney G, et al. A prospec t iv e c omparison of magnet ic resonanc e c holangiopanc reat ography w it h endosc opic ret rograde c holangiopanc reat ography in t he ev aluat ion of pat ient s w it h suspec t ed biliary t rac t disease. Clin Radiol. 1999;54:513–520. 247. Varghese JC, Liddell RP, F arrell MA, et al. T he diagnost ic ac c urac y of magnet ic resonanc e c holangiopanc reat ography and ult rasound c ompared w it h direc t c holangiography in t he det ec t ion of c holedoc holit hiasis. Clin Radiol. 1999;54:604–614.

248. Verbeek PC, v an Leeuw en DJ, de Wit LT , et al. Benign f ibrosing disease of t he hepat ic c onf luenc e mimic king Klat skin t umors. Sur ger y 1992;112:866–871. 249. Vilgrain V, Palazzo L. Choledoc holit hiasis: role of US and endosc opic ult rasound. Abdom Im aging. 2001;26:7–14. 250. Vilgrain V, Van Beers B, F lejou JF , et al. Int rahepat ic c holangioc arc inoma: MRI and pat hologic c orrelat ion in 14 pat ient s. J Com put Assist T om ogr . 1997;21:59–65. 251. Vit ellas KM, El- Dieb A, Vasw ani KK, et al. MR c holangiopanc reat ography in pat ient s w it h primary sc lerosing c holangit is: int erobserv er v ariabilit y and c omparison w it h endosc opic ret rograde c holangiopanc reat ography . AJR Am J Roent genol. 2002;179: 399–407. 252. Vit ellas KM, Enns RA, Keogan MT , et al. Comparison of MR c holangiopanc reat ographic t ec hniques w it h c ont rast - enhanc ed c holangiography in t he ev aluat ion of sc lerosing c holangit is. AJR Am J Roent genol. 2002;178:327–334.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2106

13 - The Biliary Tract 253. Vit ellas KM, Keogan MT , F reed KS, et al. Radiologic manif est at ions of sc lerosing c holangit is w it h emphasis on MR c holangiopanc reat ography . Radiogr aphic s 2000;20:959–975.

254. Vit ellas KM, Keogan MT , Sprit zer CE, et al. MR c holangiopanc reat ography of bile and panc reat ic duc t abnormalit ies w it h emphasis on t he single- shot f ast spin- ec ho t ec hnique. Radiogr aphic s 2000;20:939–957. 255. Walker AT , Shapiro AW, Brooks DC, et al. Bile duc t disrupt ion and biloma af t er laparosc opic c holec y st ec t omy : imaging ev aluat ion. AJR Am J Roent genol. 1992;158:785–789. 256. Walsh RM, Henderson JM, Vogt DP, et al. T rends in bile duc t injuries f rom laparosc opic c holec y st ec t omy . J Gast r oint est Sur g. 1998;2:458–462. P.972 257. Wat anabe Y , Dohke M, Ishimori T , et al. Pseudo- obst ruc t ion of t he ext rahepat ic bile duc t due t o art if ac t f rom art erial pulsat ile c ompression: a diagnost ic pit f all of MR c holangiopanc reat ography . Radiology 2000;214:856–860. 258. Wat anabe Y , Dohke M, Ishimori T , et al. Diagnost ic pit f alls of MR c holangiopanc reat ography in t he ev aluat ion of t he biliary t rac t and gallbladder. Radiogr aphic s 1999;19:415–429. 259. Wohlgemut h WA, Bot t ger J, Bohndorf K. MRI, CT , US and ERCP in t he ev aluat ion of bile duc t hamart omas (v on Mey enburg c omplex): a c ase report . Eur Radiol. 1998;8:1623–1626. 260. Wood T F , Rose DM, Chung M, et al. Radiof requenc y ablat ion of 231 unresec t able hepat ic t umors: indic at ions, limit at ions, and c omplic at ions. Ann Sur g Onc ol. 2000;7:593–600. 261. Wy song CB, Gort en RJ. Int rahepat ic gallbladder. Sout h Med J 1980;73:825–826. 262. Y amashit a K, Jin MJ, Hirose Y , et al. CT f inding of t ransient f oc al inc reased at t enuat ion of t he liv er adjac ent t o t he gallbladder in ac ut e c holec y st it is. AJR Am J Roent genol. 1995;164:343–346. 263. Y ee K, Sheppard BC, Domreis J, et al. Canc ers of t he gallbladder and biliary duc t s. Onc ology (Hunt ingt ). 2002;16:939–946. 264. Y oon KH, Ha HK, Kim CG, et al. Malignant papillary neoplasms of t he int rahepat ic bile duc t s: CT and hist opat hologic f eat ures. AJR Am J Roent genol. 2000;175:1135–1139. 265. Y oshida Y , Imai Y , Murakami T , et al. Int rahepat ic c holangioc arc inoma w it h marked hy perv asc ularit y . Abdom Im aging. 1999;24: 66–68.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2107

13 - The Biliary Tract

266. Y oshimit su K, Honda H, Jimi M, et al. MR diagnosis of adenomy omat osis of t he gallbladder and dif f erent iat ion f rom gallbladder c arc inoma: import anc e of show ing Rokit ansky - Asc hof f sinuses. AJR Am J Roent genol. 1999;172:1535–1540. 267. Y oungw irt h LD, Pet ers JC, Perry MD. T he suprahepat ic gallbladder. An unusual anat omic al v ariant . Radiology 1983;149: 57–58. 268. Y un EJ, Cho SG, Park S, et al. Gallbladder c arc inoma and c hronic c holec y st it is: dif f erent iat ion w it h t w o- phase spiral CT . Abdom Im aging. 2004;29:102–108. 269. Zajko AB, Campbell WL, Logsdon GA, et al. Cholangiographic f indings in hepat ic art ery oc c lusion af t er liv er t ransplant at ion. AJR Am J Roent genol. 1987;149:485–489.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

Thi s pa ge i s i ntenti ona l l y l eft bl a nk. Remove thi s text from the ma nua l templ a te i f you wa nt i t compl etel y bl a nk.

14 - Spleen

2110

14 - Spleen 19

14 - Spleen Editors: Le e , Jose ph K. T. ; Sa ge l, Stua rt S. ; Sta nle y , Robe rt J. ; He ike n, Ja y P. Title : C ompute d Body Tomogra phy with MRI C orre la tion , 4th Edition Copy right В©2006 Lippinc ot t Williams & Wilkins > T able of Cont ent s > 14 - Spleen

14 Spleen Da v id M. Wa rsha ue r T he spleen is w ell seen on c omput ed t omography (CT ) and magnet ic resonanc e (MR) images of t he abdomen in v irt ually ev ery pat ient . Normally , it appears as an oblong or ov oid organ in t he lef t upper abdomen. T he c ont our of t he superior lat eral border of t he spleen is c onv ex, c onf orming t o t he shape of t he adjac ent abdominal w all and lef t hemidiaphragm. T he margins of t he spleen are smoot h, and t he parenc hy ma is sharply demarc at ed f rom t he adjac ent f at . T he hilum usually is direc t ed ant eromedially , and t he splenic art ery and v ein and t heir branc hes c an be seen ent ering t he spleen in t his region (F ig. 14- 1). T he post eromedial surf ac e of t he spleen behind t he hilum of t en is c onc av e w here it c onf orms t o t he shape of t he adjac ent lef t kidney . T he medial surf ac e ant erior t o t he hilum is in c ont ac t w it h t he st omac h and also assumes a shallow c onc av e shape in some pat ient s (F ig. 14- 2). On images perf ormed w it hout int rav enous (IV) injec t ion of c ont rast mat erial, t he normal spleen appears homogeneous in densit y , w it h CT at t enuat ion v alues in t he range of 55 t o 65 Hounsf ield unit s (HU), equal t o or slight ly less t han t hose f or t he normal liv er (210). Like t he liv er, t he spleen ordinarily has a small area t hat is not c ov ered by perit oneum, a so- c alled bare area (341). Smaller t han t he bare area of t he liv er, t his c orresponds t o an approximat ely 2 Г— 3 c m port ion of t he spleen's surf ac e c ont ained bet w een t he ant erior and post erior leav es of t he splenorenal ligament . T his area ov erlies t he renal f asc ia c ov ering t he ant erior aspec t of t he upper pole of t he lef t kidney . Asc it es and ot her int raperit oneal lef t upper abdominal f luid c ollec t ions t end t o surround all surf ac es of t he spleen exc ept t his small area. Rec ognit ion of t his f eat ure is oc c asionally helpf ul in det ermining w het her f luid lies in t he perit oneal spac e or lef t pleural spac e.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2111

14 - Spleen T he splenic v essels are seen ev en on non–c ont rast - enhanc ed CT images in most indiv iduals. T he splenic v ein f ollow s a f airly st raight c ourse t ow ard t he

splenic hilum, running t ransv ersely along t he post erior aspec t of t he body and t ail of t he panc reas. Unlike t he splenic v ein, t he splenic art ery of t en is t ort uous, espec ially in older pat ient s. On any giv en sec t ion, it may appear as a single c urv ilinear st ruc t ure or it may w ander in and out of t he plane of t he sec t ion and appear as a series of round densit ies, eac h of w hic h represent s a c ross- sec t ional image of a port ion of t he art ery . In older indiv iduals, it is c ommon t o see c alc if ied at heromas w it hin t he w all of t he splenic art ery .

USE OF CONTRAST MATERIAL It is usef ul t o administ er iodinat ed c ont rast mat erial int rav enously (IV) w hen examining t he spleen by CT . Dy namic sc ans perf ormed during a bolus injec t ion are opt imal f or c larif y ing t he nat ure of sof t - t issue st ruc t ures in t he splenic hilar and ret ropanc reat ic regions t hat c an mimic abnormalit ies of t he panc reas or lef t adrenal gland, but t hat may , in f ac t , be t he result of normal splenic v asc ulat ure. T he splenic art ery and v ein and t heir branc hes undergo dense c ont rast enhanc ement during bolus injec t ion and are easily ident if ied. Splenic parenc hy mal opac if ic at ion also oc c urs and may be used t o improv e t he det ec t abilit y of mass lesions w it hin t he spleen. When c ont rast mat erial is giv en by rapid IV injec t ion and sc ans are obt ained early in t he injec t ion, t he splenic parenc hy ma init ially appears het erogeneous (F ig. 14- 3). Arc if orm and w av e- like pat t erns c an be seen during t his phase. T his het erogeneous enhanc ement is t hought t o be t o t he result of t he dual c irc ulat ory rout es t hrough t he splenic red pulp. Early enhanc ing areas ref lec t t he f ast c irc ulat ion w it h it s direc t art eriole t o v enule c onnec t ion, w hereas t he lat e enhanc ing areas ref lec t t he slow c irc ulat ion of art eriole t o c ords of Bilrot h t o v enular f low (117,191,335). Only af t er a minut e or more passes does t he splenic parenc hy ma ac hiev e unif orm, homogeneous P.974 enhanc ement . In w ork done w it h a pediat ric populat ion, t his early het erogeneit y has been show n t o be relat ed t o injec t ion rat e, age, and splenomegaly , w it h het erogeneit y oc c urring more f requent ly at higher injec t ion rat es, in pat ient s older t han 1 y ear of age, and in pat ient s w it hout splenomegaly (81). Care must be t aken not t o misint erpret t his early post injec t ion het erogeneit y as an indic at ion of f oc al abnormalit y .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2112

14 - Spleen

F igure 14- 1 Comput ed t omography image of normal spleen (S). T he out er border is c onv ex and c onf orms t o t he shape of t he adjac ent body w all. T he medial surf ac e is c onc av e. T he splenic art ery (ar r ow ) ent ers t he hilum. C, c olon; G, st omac h; L, liv er.

F igure 14- 2 Coronal T 1- w eight ed f ast low - angle shot magnet ic resonanc e image (repet it ion t ime, 140 ms; ec ho t ime, 4 ms; f lip angle, 80 degrees) of normal spleen (S). Not e t he int imat e relat ion of t he spleen t o t he lef t hemidiaphragm, gast ric f undus (G), lef t kidney (K), and c olon (C). Also not e a large right adrenal c arc inoma (A).

No signif ic ant dif f erenc e in splenic parenc hy mal enhanc ement has been show n bet w een ionic and nonionic c ont rast mat erial (129,210). Af t er administ rat ion

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2113

14 - Spleen of 180 mL of iot halamat e- 60%, iopamidol- 300, or iohexol- 300 at 2 mL per sec ond, mean enhanc ement of splenic parenc hy ma ranges f rom 75 t o 97 HU (210).

F igure 14- 3 Comput ed t omography appearanc e of t he normal spleen (S) during bolus int rav enous injec t ion of c ont rast mat erial. A: Pat c hy pat t ern of early splenic parenc hy mal enhanc ement 30 sec onds af t er t he st art of c ont rast injec t ion. T he aort a and splenic v essels are densely opac if ied. B: Unif orm appearanc e of splenic parenc hy ma 70 sec onds af t er t he st art of c ont rast injec t ion.

MAGNETIC RESONANCE IMAGING T he adult spleen has relat iv ely long T 1 and T 2 relaxat ion t imes. It s signal int ensit y on T 1- w eight ed images is less (i.e., darker) t han t hat of liv er and is similar t o t hat of renal c ort ex. On T 2- w eight ed images, t he spleen appears bright er t han liv er, ref lec t ing it s great er f ree w at er c ont ent (F ig. 14- 4). Unlike in t he adult , t he neonat al spleen is init ially isoint ense or hy point ense t o liv er on T 2- w eight ed images during t he f irst w eeks of lif e, only assuming an adult appearanc e af t er 8 mont hs. T his inc rease in T 2- w eight ed signal is t hought P.975 t o c orrelat e w it h mat urat ion of t he ly mphoprolif erat iv e sy st em, w it h result ing inc rease in t he w hit e pulp t o red pulp rat io (80). Breat h- hold spoiled gradient ec ho t ec hniques [e.g., f ast low - angle shot (F LASH)] hav e prov ed t o be usef ul in splenic ev aluat ion by dec reasing t ime of ac quisit ion and henc e respirat ory mot ion art if ac t . T he f low v oid produc ed by mov ing blood allow s t he major splenic v essels t o be seen w ell, w it hout t he use of IV c ont rast mat erial. Bec ause t he t issue relaxat ion t imes of splenic parenc hy ma and many t umors of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2114

14 - Spleen

t he spleen are similar (126), t he use of IV c ont rast mat erial f or ev aluat ing t he spleen has bec ome import ant (193,282). Gadolinium–diet hy lene- t riamine pent a- ac et ic ac id (Gd- DT PA) is t he agent used most c ommonly . Mult isec t ion T 1- w eight ed spoiled gradient ec ho sequenc es c an be employ ed at v arious t imes af t er c ont rast mat erial injec t ion t o image t he spleen in t he early , mid- , and lat e perf usion phases (F ig. 14- 5). P.976 Using t his t ec hnique, approximat ely 80% of pat ient s demonst rat e normal het erogeneous or arc if orm enhanc ement on early perf usion images; 15% show unif orm high signal (282). T he signif ic anc e of t he early unif orm enhanc ement is unc ert ain, alt hough it has been spec ulat ed t hat it may represent a response t o a c oexist ing inf lammat ory or neoplast ic proc ess (282).

F igure 14- 4 Magnet ic resonanc e imaging appearanc e of t he normal spleen (S). A: On t his T 1- w eight ed f ast low - angle shot image (repet it ion t ime, 142 ms; ec ho t ime 4.4 ms; f lip angle, 80 degrees), t he signal int ensit y of t he spleen (S) is less t han t hat of t he liv er (L) and muc h less t han t hat of t he surrounding f at . B: On a T 2- w eight ed half - F ourier ac quisit ion single- shot t urbo spin- ec ho magnet ic resonanc e image (1,500/92), t here is rev ersal of t he relat iv e signal int ensit ies of t he spleen (S) and liv er (L).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2115

14 - Spleen

F igure 14- 5 Magnet ic resonanc e imaging appearanc e of t he normal spleen (S). A: On t his T 1- w eight ed f ast low - angle shot image (repet it ion t ime, 140 ms; ec ho t ime, 4 ms; f lip angle, 80 degrees) perf ormed during t he perf usion phase of int rav enous administ rat ion of gadolinium- diet hy lene- t riamine pent aac et ic ac id, t he splenic parenc hy ma show s het erogeneous enhanc ement . B: T he spleen has assumed a more homogeneous appearanc e 45 sec onds lat er.

At present , IV c ont rast –enhanc ed MRI appears t o be as sensit iv e as or slight ly more sensit iv e t han CT f or ev aluat ion of t he splenic parenc hy ma. T he abilit y of MRI t o direc t ly image in t he c oronal and sagit t al planes is adv ant ageous in show ing t he relat ion of t he spleen t o t he adjac ent lef t kidney , adrenal, and hemidiaphragm, alt hough t his adv ant age has diminished w it h t he av ailabilit y of isot ropic imaging w it h mult islic e CT . Respirat ory mot ion art if ac t and t he inc reased c ost and t ime inv olv ed in an MRI st udy , how ev er, limit it s rout ine use.

SPLENIC SIZE T he spleen measures f rom 12 t o 15 c m in lengt h, 4 c m t o 8 c m in w idt h, and 3 t o 4 c m in t hic kness (10). Bec ause of t he spleen's irregular shape and oblique orient at ion w it hin t he lef t upper quadrant , t hese measurement s are of limit ed use as a guide t o normal splenic size on CT . Many observ ers judge splenic v olume by subjec t iv e ev aluat ion of t he CT image based on experienc e. Rounding of t he normally c resc ent ic spleen and ext ension of t he spleen ant erior t o t he aort a or below t he right hepat ic lobe or rib c age are f urt her c lues t o splenomegaly .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2116

14 - Spleen A more ac c urat e approac h t o t he assessment of splenic v olume is t he splenic index (172,310), w hic h is t he produc t of t he lengt h, w idt h, and t hic kness of

t he spleen as seen on CT (F ig. 14- 6). Splenic lengt h is det ermined by summing t he number of c ont iguous CT slic es on w hic h t he spleen is v isible. T he w idt h is t he longest splenic diamet er t hat c an be draw n on any t ransv erse image. T he t hic kness is measured at t he lev el of t he splenic hilum and is t he dist anc e bet w een t he inner and out er (peripheral) borders of t he spleen. When t he t hic knesses of t he ant erior and post erior port ions of t he spleen dif f er signif ic ant ly , t w o or t hree measurement s of t hic kness are av eraged. When det ermined in t his w ay , t he normal splenic size c orresponds t o an index of 120 t o 480 c m (172). T he c orrelat ion bet w een splenic index (and ot her simplif ied linear measures) and ac t ual splenic v olume c alc ulat ed on a per- slic e basis is good (245,270,276), alt hough t he c orrelat ion w it h t he w eight of t he surgic ally exc ised spleen is an imperf ec t one. It has been demonst rat ed t hat t he w eight of t he exc ised spleen in grams av erages f rom one t hird t o one half t he splenic index (113,310). T his is not surprising, bec ause t he size and w eight of t he exc ised spleen are af f ec t ed by t he amount of blood t hat drains f rom t he spec imen bef ore it is w eighed. T he splenic index as det ermined by CT is probably a bet t er indic at or of splenomegaly t han is t he w eight of t he spleen as det ermined in t he operat ing room or pat hology laborat ory .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2117

14 - Spleen

F igure 14- 6 Diagrammat ic represent at ion of t he measurement s used in c alc ulat ing t he splenic index f rom t ransv erse c omput ed t omography or magnet ic resonanc e images of spleens of v arious shapes. T he w idt h (solid lines) and t hic kness (dashed lines) are show n. (See t ext f or det ails.)

Most ac c urat e of all are c omput er programs f or c alc ulat ing ac t ual splenic v olume f rom a series of CT or MR images. Calc ulat ed adult splenic v olume has ranged in v arious st udies of normal v olunt eers f rom a mean of 112 c m3 (range 32 t o 209 c m3) t o 214 c m3 (range 107 t o 315 c m3) (149,246). Splenic v olume did not c orrelat e w it h gender, body mass index, or body w eight (149,246). Alt hough an inv erse c orrelat ion w as not ed w it h age in one st udy , t his w as not seen in any ot her report (149,246).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2118

14 - Spleen NORMAL VARIANTS AND CONGENITAL ANOMALIES T he spleen f orms f rom mult iple mesenc hy mal c ell aggregat es in t he dorsal mesogast rium. As t he dorsal mesent ery bow s t o t he lef t w it h t he dev eloping st omac h, t hese aggregat es c oalesc e. T he lef t side of t he dorsal mesent ery

f uses w it h t he pariet al perit oneum c ov ering t he lef t adrenal and kidney t o f orm Gerot a's f asc ia. T his f usion brings t he dev eloping dorsal panc reas and splenic v asc ulat ure int o t he ret roperit oneum. T he spleen, how ev er, remains int raperit oneal, w it h it s v asc ulat ure running in t he splenorenal ligament . T he gast rosplenic ligament represent s t he remaining ant erior port ion of t he dorsal mesogast rium and c onnec t s t he spleen t o t he great er c urv at ure of t he st omac h. T he P.977 c ombinat ion of bot h splenorenal and gast rosplenic ligament s f orms t he deep margins of t he lesser sac (79).

F igure 14- 7 Normal v ariat ions in splenic shape. A: A prominent lobule of splenic t issue is seen ext ending medially f rom t he post erior margin of t he spleen (S). B: A prominent splenic lobule is not ed ext ending of f t he ant erior margin of t he spleen (S).

Splenic Lobulation In light of t his f airly c omplex dev elopment , it should not be surprising t hat t he shape and posit ion of t he normal spleen v ary c onsiderably f rom one indiv idual

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2119

14 - Spleen t o anot her (110). Commonly , t here is a bulge or lobule of splenic t issue t hat

ext ends medially f rom t he post erior port ion of t he spleen t o lie ant erior t o t he upper pole of t he lef t kidney (F ig. 14- 7) (121,162,236). T his c an simulat e t he appearanc e of a lef t renal or adrenal mass on exc ret ory urography , but is usually ident if iable w it hout dif f ic ult y by CT . Less c ommonly , a bulge f rom t he ant erior margin of t he spleen also oc c urs and c an simulat e an int rasplenic mass. Oc c asionally , a lobule of splenic t issue c an lie part ially behind t he lef t kidney and displac e it ant eriorly . Residual c lef t s bet w een adjac ent lobulat ions c an be sharp and oc c asionally are as deep as 2 t o 3 c m (F ig. 14- 8). T hey t end t o oc c ur on t he superior diaphragmat ic port ion of t he spleen and may mimic lac erat ions (79).

F igure 14- 8 Prominent splenic c lef t s bet w een adjac ent splenic lobulat ions. T his anat omic v ariat ion c an simulat e a splenic lac erat ion. A: Prominent c lef t (ar r ow ) along t he ant erior margin of t he spleen. B: Bif id splenic c lef t (ar r ow ) along t he post erior splenic margin. S, spleen; G, st omac h; A, asc it es.

T he spleen is suf f ic ient ly sof t and pliable in t ext ure t hat lef t upper quadrant abdominal masses or organ enlargement c an c ause c onsiderable displac ement and def ormit y of it s shape. When t his happens, t he spleen c onf orms t o P.978 t he shape of t he adjac ent mass, and t he result ing def ormit y c an be quit e st riking (F ig. 14- 9). Likew ise, c hanges in t he posit ion of t he spleen oc c ur w hen adjac ent organs are surgic ally remov ed. T his is part ic ularly t rue in pat ient s w ho hav e undergone lef t nephrec t omy , in w hic h c ase t he spleen c an oc c upy t he lef t renal f ossa. Oc c asionally , t here is suf f ic ient laxit y in t he ligament ous at t ac hment s of t he spleen t hat it lies in an unusual posit ion in t he absenc e of an abdominal mass or prev ious operat ion. T he upside- dow n spleen

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2120

14 - Spleen (69,357) is a v ariant in w hic h t he splenic hilum is direc t ed superiorly t ow ard t he medial, or oc c asionally t he lat eral, port ion of t he lef t hemidiaphragm.

F igure 14- 9 Marked alt erat ion in splenic shape and posit ion result ing f rom c ompression by a lef t subphrenic absc ess (A). A: Axial slic e. S, spleen; A, subphrenic absc ess; G, st omac h. B: Coronal rec onst ruc t ion. S, spleen; A, subphrenic absc ess, arrow s, hemidiaphragm.

“Wandering” Spleen T he “ w andering” spleen is anot her c ongenit al v ariant t hat somet imes c auses diagnost ic dif f ic ult ies. In t his rare c ondit ion, most c ommon in w omen, t here is st riking laxit y of t he suspensory splenic ligament s, w hic h permit s t he spleen t o mov e about in t he abdomen (8,40). T he CT f indings c onsist of an abdominal sof t - t issue- densit y “ mass” w it h a size appropriat e f or t he spleen, plus t he absenc e of a spleen in t he normal loc at ion (F ig. 14- 10). It may be possible t o rec ognize t he c harac t erist ic shape of t he spleen and splenic hila and t o t rac e t he splenic v asc ulat ure bac k t o it s origin. A w hirled appearanc e t o t he v asc ulat ure may be seen if t orsion is present (256). T he densit y and pat t ern of enhanc ement af t er bolus injec t ion of c ont rast mat erial may also lend support t o t he diagnosis. When t here is unc ert aint y w het her t he mass t ruly represent s an ec t opic ally loc at ed spleen, radionuc lide imaging w it h t ec hnet ium- 99m ( 99mT c )- sulf ur c olloid c an resolv e t he dilemma (8). T he most c ommon c linic al present at ion is t hat of a mass, w it h int ermit t ent abdominal pain. Less c ommonly , an asy mpt omat ic mass is disc ov ered in t he abdomen or pelv is (72). An ac ut e abdominal present at ion is least c ommon but most w orrisome and indic at es t orsion and c ompromise of t he v asc ular supply

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2121

14 - Spleen (25,40,53,54,55,256,275,287). Wit h inf arc t ion, t he radionuc lide st udy c an be

f alsely negat iv e (287). Alt hough splenic enhanc ement is absent w it h c omplet e inf arc t ion, t he remaining CT f indings should st ill allow f or a c orrec t diagnosis (134,211). Asc it es c an also be present (134,287). If t he panc reat ic t ail is inv olv ed in t he t orsion, CT c an demonst rat e a w horled appearanc e of t he panc reat ic t ail and adjac ent f at (228). A t hic k, enhanc ing pseudoc apsule represent ing oment al and perit oneal adhesions has been desc ribed in one c ase in w hic h t orsion and inf arc t ion w ere missed f or sev eral w eeks (289). Chronic t orsion w it h v enous c ongest ion also has been report ed t o lead t o t he dev elopment of splenomegaly , hy persplenism, and gast ric v aric es (40,114). Panc reat it is has also been report ed as a c onsequenc e of t orsion and t he result ant obst ruc t ion of t he panc reat ic t ail (60,114,206). Int est inal obst ruc t ion has also been report ed as a c omplic at ion sec ondary t o ileal v olv ulus around t he splenic pedic le (116).

Accessory Spleens An ac c essory spleen is a c ommon f inding on CT and arises as a result of f ailure of f usion of some of t he mult iple buds of splenic t issue in t he dorsal mesogast rium during embry onic lif e. In aut opsy series, ac c essory spleens are not ed in 10% t o 20% of indiv iduals (128,346). Alt hough ac c essory spleens are usually single, approximat ely 10% of pat ient s w it h one ac c essory spleen hav e a sec ond f oc us. More t han t w o deposit s are seen inf requent ly (5%) (128,346). St udies on pat ient s w ho hav e undergone splenec t omy show an P.979 inc reased prev alenc e of bot h single and mult iple ac c essory spleens, probably bec ause t he underly ing pat hology nec essit at ing splenec t omy has made mic rosc opic deposit s c linic ally apparent (68,89).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2122

14 - Spleen

F igure 14- 10 Wandering spleen. A: No splenic shadow is seen in t he lef t upper abdomen. K, kidney . B: T he spleen (S) is seen in t he low er midabdomen and mimic s t he appearanc e of an abdominal t umor, Arrow , splenic hila. C : Sagit t al rec onst ruc t ion show s t he splenic v ein (ar r ow s) running c ephalad. Marked splenomegaly in t his c ase is sec ondary t o mononuc leosis. K, kidney ; P, psoas musc le.

Ac c essory spleens usually oc c ur near t he hilum of t he spleen (F ig. 14- 11), but t hey are somet imes f ound in it s suspensory ligament s or in t he t ail of t he panc reas (F ig. 14- 12) (63,133,174,294). Rarely , t hey oc c ur elsew here in t he abdomen or ret roperit oneum (76,300,330). T hey v ary in size f rom mic rosc opic deposit s t hat are not v isible on CT or MRI, t o nodules t hat are 2 t o 3 c m in diamet er (22,128,346). In pat ient s w it h pat hologic splenic f indings or t hose w ho hav e prev iously undergone splenec t omy , ac c essory spleens c an hy pert rophy and reac h a size of 5 c m or more (22). T he t y pic al ac c essory

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2123

14 - Spleen

spleen has a smoot h, round or ov oid shape. It s blood supply is usually deriv ed f rom t he splenic art ery w it h drainage oc c urring int o t he splenic v ein. In most pat ient s, ac c essory spleens represent an inc ident al f inding of no c linic al signif ic anc e. Oc c asionally , it is import ant t o ident if y ac c essory splenic t issue, part ic ularly w hen it is c onf used w it h a mass of anot her t y pe. F or inst anc e, an ac c essory spleen c an mimic t he f indings of a gast ric (147), panc reat ic (63,133,174,294), lef t adrenal (309,330), hepat ic (76), or ot her mass. Ident if ic at ion is part ic ularly c ruc ial in pat ient s in w hom a splenec t omy w as init ially perf ormed f or a hemat ologic disorder result ing in hy persplenism. In t hese pat ient s, t he grow t h of ac c essory splenic t issue c an lead t o a ret urn of splenic hy perac t iv it y , w it h a result ant relapse (9). T orsion and inf arc t ion hav e also been report ed inv olv ing an ac c essory spleen and c an present as a P.980 painf ul abdominal mass (234,338). Spont aneous rupt ure has also been report ed (67). Ot her splenic lesions, suc h as c ongenit al c y st s, hav e also been report ed in ac c essory spleens and may c omplic at e t heir ident if ic at ion (106).

F igure 14- 11 Ac c essory spleen A: Small ac c essory spleen (ar r ow ) adjac ent t o t he splenic hilum. S, spleen. B: Enlarged ac c essory spleen (AS) in a pat ient w it h my eloid met aplasia. S, spleen; arrow , small inf arc t .

When t here is unc ert aint y w het her a nodule seen on CT represent s an ac c essory spleen, one c an c ompare t he CT at t enuat ion number of t he st ruc t ure in quest ion w it h t hat of t he spleen bef ore and af t er IV injec t ion of c ont rast mat erial. Ac c essory splenic t issue t ends t o exhibit t he same pat t ern of c ont rast enhanc ement as does t he spleen it self (117). In problemat ic c ases, a radionuc lide st udy ( 99mT c sulf ur c olloid sc an or heat - damaged t agged red blood c ell st udy ) may prov e usef ul (22,131,223). Ult rasound (US) also has

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2124

14 - Spleen been used t o doc ument t hat t he v essels supply ing a presumed ac c essory spleen arise f rom t he splenic art ery and v ein (312). In c ases of t orsion, t he ac c essory spleen has appeared as a hy podense sof t t issue mass w it h a t hic k hy perenhanc ing pseudoc apsule t hat may be indist inguishable f rom ot her ent it ies suc h as an absc ess, pseudoc y st , or t orsed mesent eric c y st (338).

F igure 14- 12 Int rapanc reat ic ac c essory spleen.A: T 1- w eight ed f at - sat urat ed f ast low - angle shot (F LASH) image show s an int ermediat e- signal rounded mass in t he t ail of t he panc reas. B: T 1- w eight ed F LASH image perf ormed during t he early art erial phase of int rav enous administ rat ion of gadolinium—diet hy lenet riamine pent a- ac et ic ac id show s early het erogeneous enhanc ement of t he mass. Surgic al remov al rev ealed an ac c essory spleen. T he pat ient had idiopat hic t hromboc y t openia and had undergone prior splenec t omy .

P.981

Polysplenia Poly splenia is a rare c ombinat ion of c ongenit al anomalies c harac t erized by mult iple aberrant splenic nodules and malf ormat ions in ot her organ sy st ems. Alt hough f requent ly ref erred t o as lef t isomerism (bilat eral lef t - sidedness), t he assoc iat ed abnormalit ies are c omplex and c harac t erized by no single pat hognomonic anomaly (T able 14- 1) (233,363). In most c ases, t he spleen is div ided int o 2 t o 16 masses of equal size. T hese are loc at ed in eit her t he right or lef t upper quadrant along t he great er c urv e of t he st omac h (F ig. 14- 13). Less c ommonly , t here are one or t w o large spleens along w it h sev eral small splenules. Rarely , t here may be only a single bilobed spleen (233). Anomalous posit ions of ot her abdominal v isc era also c an oc c ur. In one st udy of 146 c ases of poly splenia (233), a sy mmet ric midline posit ion of t he liv er w as not ed in

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2125

14 - Spleen 57%, w it h 21% hav ing f ull sit us inv ersus. In 65% of pat ient s, int errupt ion of

t he inf erior v ena c av a w it h azy gous c ont inuat ion w as not ed. A short panc reas in w hic h t he body and t ail are t runc at ed also has been observ ed f requent ly (109,125,134). A semiannular panc reas (161) has also been not ed. Abnormal rot at ion of t he bow el w as c ommon and usually c harac t erized as eit her rev erse rot at ion or nonrot at ion of t he midgut loop (109). A preduodenal port al v ein w as not ed in sev en of eight pat ient s desc ribed in one series (109,161). Genit ourinary t rac t anomalies, inc luding renal agenesis or hy poplasia and mult iple uret ers, are also observ ed. TABLE 14- 1 SUMMARY OF ANOMALIES IN ASPLENIA AND POLY SPLENIA Anoma ly

Asple nia (right Poly sple nia (le ft isome rism) isome rism) Lungs Bilat eral t rilobed lungs Bilat eral bilobed lungs (69%) (58%) Superior v ena c av a (SVC) Bilat eral SVC (53%) Bilat eral SVC (47%) Inf erior v ena c av a (IVC) Normal IVC- Dat rial Azy gous c ont inuat ion of c ommunic at ion IVC (65%) Cardiac Single at riov ent ric ular At rial sept al def ec t (78%) v alv e (87%) Vent ric ular sept al def ec t Absent c oronary sinus (63%) (85%) Right sided aort ic arc h Pulmonary st enosis or (44%) at resia (78%) Part ial anomalous T ot al anomalous pulmonary v enous ret urn pulmonary v enous ret urn (39%) (72%) Mal- or t ransposit ion of T ransposit ion of great great v essels (31%) v essels (72%) Pulmonary v alv ular At rial sept al def ec t st enosis (23%) (66%) Subaort ic st enosis (8%) Single v ent ric le (44%) Spleen Absent Mult iple spleens Gast roint est inal t rac t Abdominal het erot axia Abdominal het erot axia (38%) (57%) Sit us inv ersus (15%) Sit us inv ersus (21%) Part ial sit us inv ersus Sit us solit us (21%) (15%) Sit us solit us (31%) Genit ourinary t rac t Misc ellaneous anomalies Misc ellaneous anomalies (15%) (17%) Dat a f rom Peoples WM, Moller JH, Edw ards JE. Poly splenia: a rev iew of 146 c ases. Pediat r Cardiol 1983;4:129–137 (poly splenia) and Rose V, Izukaw a T , Moes CAF . Sy ndromes of asplenia and poly splenia: a rev iew of c ardiac and non- c ardiac malf ormat ions in 60 c ases w it h spec ial ref erenc e t o diagnosis and prognosis. Br Hear t J 1975;37:840- 852 (asplenia).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2126

14 - Spleen

F igure 14- 13 Poly splenia. Mult iple splenules (S) are seen in t he right upper quadrant . T he azy gos v ein (ar r ow ) is prominent , and t he inf erior v ena c av a is absent . Not e t hat t he pat ient has sit us inv ersus, alt hough t he image is display ed rev ersed f or v iew ing purposes.

Assoc iat ed t horac ic anomalies inc lude bilat eral morphologic lef t lungs (i.e., w it h t w o lobes and hy part erial bronc hus) in 58% of c ases. Bilat eral superior v ena c av a, right - sided aort ic arc h, and part ial anomalous pulmonary v enous ret urn oc c ur in 40% t o 50% of pat ient s. Cardiac anomalies are c ommon and are t he usual c ause of deat h, w it h half of pat ient s suc c umbing bef ore 6 mont hs of age. P.982 T he most c ommon c ardiac anomalies are at rial sept al def ec t , v ent ric ular sept al def ec t , malposit ion or t ransposit ion of t he great v essels, and pulmonary st enosis or at resia (233). Alt hough only 10% of pat ient s surv iv ed t o midadolesc enc e in one report ed series (233), it is import ant t o not e t hat t he poly splenia sy ndrome oc c asionally c an exist w it hout signif ic ant c ardiac anomalies and may be disc ov ered as an inc ident al f inding on CT (109,284,301,363). CT or MRI may be used t o c harac t erize t he v isc eral anomalies (144,344).

Asplenia T he c ongenit al asplenia sy ndrome (right isomerism or Iv emark sy ndrome) is c harac t erized by an absent spleen and mult iple anomalies in bot h t he abdomen and t horax (T able 14- 1). T he inf erior v ena c av a–right at rial c ommunic at ion

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2127

14 - Spleen is usually normal; how ev er, abnormal v isc eral posit ion is f requent ly observ ed. In one st udy of 39 c ases of asplenia (267), t ot al or part ial sit us inv ersus w as not ed in 31%, w it h abdominal het erot axy seen in 38%. Assoc iat ed int est inal malrot at ion is c ommon (194), genit ourinary t rac t anomalies are seen in 15% (267), and bilat eral morphologic right lungs are not ed in 69% of c ases (267).

T he most serious assoc iat ed anomalies are c ardiov asc ular. T hese t y pic ally are more c omplex malf ormat ions t han t hose seen w it h poly splenia. In t he series of 39 pat ient s c it ed (267), 87% had a single at riov ent ric ular v alv e and a single v ent ric le w as seen in 44%. T ransposit ion of t he great v essels and t ot al anomalous pulmonary v enous drainage w ere also c ommon. T hese serious anomalies ac c ount f or muc h of t he high mort alit y , w it h 80% of pat ient s dy ing by t he end of t heir f irst y ear (267). Sepsis relat ed t o asplenia also c ont ribut es t o t his mort alit y f igure. Alt hough t he majorit y of pat ient s w it h asplenia present w it h c y anosis or c ardiorespirat ory problems, a f ew present w it h bow el obst ruc t ion (194). In bot h groups, CT or MRI c an be helpf ul in suggest ing t he diagnosis and f ully c harac t erizing t he disorder (327).

Splenic–Gonadal Fusion Splenic –gonadal f usion is a rare c ongenit al anomaly in w hic h f unc t ioning splenic t issue is loc at ed in c lose proximit y t o gonadal t issue. T his ent it y is f ound predominant ly in men, w it h a male:f emale rat io of 17:1 (46). T he f unc t ioning splenic t issue, w hic h usually appears as an enc apsulat ed mass, may lie in t he epididy mis, along t he spermat ic c ord, or w it hin t he t unic a albuginea. It is hy pot hesized t hat t his anomaly arises f rom adhesion bet w een t he dev eloping gonadal primordia and t he splenic anlage prior t o gonadal desc ent . A f ibrous band t hat c an c ont ain addit ional splenic t issue is f ound ext ending t o t he main spleen in slight ly ov er half of pat ient s. T his “ c ont inuous” t y pe of splenic –gonadal f usion is assoc iat ed w it h ot her c ongenit al anomalies, inc luding limb def ec t s, mic rognat hia, and c ardiac def ec t s (197). Hernia and undesc ended t est is are assoc iat ed in 15% t o 20% of pat ient s (46). T he “ disc ont inuous” t y pe, in w hic h t here is no c onnec t ion t o t he main spleen, is usually not assoc iat ed w it h ot her c ongenit al anomalies. Alt hough t he mass is usually asy mpt omat ic , c onf usion w it h t est ic ular malignanc y or inf lammat ion c an oc c ur if t he mass is not ed on rout ine phy sic al exam or if t he splenic t issue enlarges or bec omes t ender sec ondary t o a sy st emic illness suc h as mononuc leosis or malaria (23). Suc h c onf usion c an

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2128

14 - Spleen lead t o unnec essary orc hiec t omy (23,46). Bow el obst ruc t ion produc ed by t he f ibrous band present in t he c ont inuous t y pe of f usion has also been report ed (46). 99mT c - labeled sulf ur c olloid sc an has been suggest ed as t he best proc edure t o est ablish a diagnosis of splenic –gonadal f usion in c ases in w hic h a quest ionable mass has been ident if ied w it h eit her US or CT (64,308). On CT , t he splenic t issue has been desc ribed as a w ell- def ined homogenous mass (145).

Splenorenal Fusion Splenorenal f usion is a v ery rare c ongenit al anomaly in w hic h splenic t issue has f used w it h t he kidney during embry ologic dev elopment . T he result ant mass c an mimic renal neoplasia (368).

PATHOLOGIC CONDITIONS Cysts T hree t y pes of nonneoplast ic c y st s are know n t o arise in t he spleen (70,108): hy dat id c y st s result ing f rom Ec hinoc oc c us gr anulosa inf ec t ion, c ongenit al c y st s, and post t raumat ic pseudoc y st s.

Echinococcal Cysts On a w orldw ide basis, ec hinoc oc c al inf ec t ion is t hought t o be responsible f or t w o t hirds of all splenic c y st s (108). T his is despit e t he f ac t t hat splenic inv olv ement oc c urs in less t han 2% t o 3% of c ases of ec hinoc oc c osis (34,184,242). In great er t han 70% of pat ient s w it h ec hinoc oc c al inv olv ement of t he spleen, ot her st ruc t ures also are inv olv ed, t he liv er being t he most c ommon (103,343). In Nort h Americ a, ec hinoc oc c al disease is unusual, w it h f ew er t han 200 c ases diagnosed y early . More t han 90% of t hese are ac quired on ot her c ont inent s (362). Pat ient s are f requent ly asy mpt omat ic (336). Sy mpt oms, w hen present , are generally relat ed t o t he large size of t he c y st . F ev er is not usually present unless sec ondary inf ec t ion of a c y st has dev eloped (362). When present , ec hinoc oc c al c y st s are w ell- c irc umsc ribed, low - densit y lesions t hat enlarge t he spleen (F ig. 14- 14A). Cy st w all c alc if ic at ion is c ommon, oc c urring in approximat ely half of pat ient s in t w o series (105,343). Mult iple separat e c y st s w ere also seen f requent ly , alt hough

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2129

14 - Spleen daught er c y st s and c ollapsed membranes w ere less c ommonly ident if ied. No enhanc ement of t he lesions w as observ ed on CT (105), alt hough prior st udies w it h angiography hav e show n P.983 enhanc ement of t he out er c y st w all (263). On MR, hy dat id c y st s are hy point ense c ompared w it h liv er parenc hy ma on T 1- w eight ed images and hy perint ense on T 2- w eight ed images. In 75% of c ases, t he signal int ensit y is het erogeneous. Daught er c y st s t y pic ally giv e a slight ly low er signal t han t he main c y st on T 1- w eight ed sequenc es. A c ont inuous 4- t o 5- mm- t hic k low -

int ensit y rim surrounding t he c y st usually is ev ident . T his rim c orresponds t o a dense f ibrous c apsule enc asing t he parasit ic membranes (185,342). T reat ment is by surgic al remov al. Perc ut aneous aspirat ion should be av oided bec ause of t he risk of allergic reac t ion t o c y st c ont ent s and spread of inf ec t ion (86,146).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2130

14 - Spleen

F igure 14- 14 Splenic c y st s. A: Ec hinoc oc c al c y st . A large low - densit y lesion (E) is not ed in t he spleen (S). Not e daught er c y st s lining t he lesion w it h slight ly low er at t enuat ion t han t he main c y st f luid. (Case c ourt esy of John K. Mc Larney , Armed F orc es Inst it ut e of Pat hology .) B: In anot her pat ient , a large uniloc ular low - densit y lesion is not ed. F ollow ing remov al, t his w as show n t o be an epit helial c y st (C). C : T his round and sharply c irc umsc ribed c y st (ar r ow ) w it h a c alc if ied rim w as presumed t o be sec ondary t o t rauma.

Congenital Cysts Epit helial (also c alled epidermoid, mesot helial, primary , or t rue) c y st s are c ongenit al in origin (122,200). Pat hologic ally , t hey are t rue c y st s, w it h an epit helial lining t hought t o originat e f rom perit oneal mesot helial c ells t hat hav e bec ome t rapped w it hin t he splenic parenc hy ma during dev elopment (43,70,200,224). Grossly , t hey hav e a t y pic al glist ening w hit e t rabec ulat ed surf ac e (200). Epit helial c y st s are said t o make up approximat ely 20% of nonparasit ic splenic c y st s. Some researc hers hav e suggest ed, how ev er, t hat t his perc ent age is art if ic ially low and ref lec t s an inc omplet e ev aluat ion of t he c y st lining. Epit helial c y st s are usually disc ov ered in c hildhood or in t he early adult y ears (70,88,108) and are more c ommon in f emales t han in males (70,200). Alt hough t he v ast majorit y of c ases are sporadic , f amilial oc c urrenc e has been report ed (5,115,142,255). Elev at ed serum and int rac y st ic lev els of sev eral t umor markers [c anc er ant igen (CA) 19- 9, CA 125, and c arc inoembry onic ant igen (CEA)] hav e also been report ed in pat ient s w it h large epit helial c y st s (142,181). In 80% of c ases, c ongenit al splenic c y st s are uniloc ular and solit ary . On CT , t hey appear as spheric al, sharply c irc umsc ribed, w at er- densit y lesions, t hat show no c ent ral or rim enhanc ement af t er IV administ rat ion of c ont rast mat erial (70,293)(F ig. 1414B). Alt hough usually solit ary , mult iple lesions hav e been report ed (115). CT may show c y st w all t rabec ulat ion or peripheral sept at ion. T he w all of an epidermoid c y st oc c asionally c alc if ies (70). T he MR appearanc e is usually t hat of a f luid- c ont aining c y st w it h inc reased T 2 signal and int ermediat e or low T 1 signal. Lobulat ion or t rabec ulat ion may also be v isible (293). P.984

Posttraumatic Cysts Post t raumat ic c y st s are t hought t o represent a f inal st age in t he ev olut ion of splenic hemat oma. Hist ologic ally , t hey lac k a c ellular lining and t hus are

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2131

14 - Spleen ref erred t o as pseudoc y st s (70,82,171). Grossly t hey hav e a shaggy hemorrhagic int ernal appearanc e. Most splenic c y st s enc ount ered in t he

Unit ed St at es are t hought t o be post t raumat ic in origin, alt hough t his number has been rec ent ly c hallenged (70,108,200). Like epit helial c y st s, post t raumat ic c y st s appear on CT as sharply demarc at ed lesions. T hey are almost alw ay s uniloc ular, show no enhanc ement , and c ont ain f luid of a densit y similar t o or slight ly abov e t hat of w at er (70). In one series, t he av erage great est dimension w as 13 c m, w it h no signif ic ant size dif f erenc e not ed bet w een pseudoc y st s and t rue c y st s (70). CT - v isible c alc if ic at ion w as more c ommon in pseudoc y st s t han c ongenit al c y st s (50% v ersus 14%) (F ig. 14- 14C). Cy st w all t rabec ulat ion or peripheral sept at ion w as more c ommon in c ongenit al c y st s (86% v ersus 17%). Alt hough of t en asy mpt omat ic , nonparasit ic splenic c y st s of eit her t y pe may present as a lef t upper quadrant mass, c ausing a sense of epigast ric f ullness or int ermit t ent dull pain (70,108). An ac ut e abdominal present at ion may oc c ur w it h rupt ure or inf ec t ion (70,255,258). Compression of t he lef t kidney may lead t o renal c olic , or rarely , hy pert ension (249).

Other Cystic Lesions T he dif f erent ial diagnosis of a splenic c y st inc ludes absc ess, ac ut e hemat oma, int rasplenic panc reat ic pseudoc y st (221), c y st ic neoplasm (ly mphangioma or hemangioma), and c y st ic or nec rot ic met ast asis (70,90,337).

Benign Splenic Tumors Hemangiomas Benign splenic t umors are unc ommon. Hemangiomas and ly mphangiomas are t he t w o most f requent t y pes, w it h hemangiomas seen in 0.01% t o 0.14% of pat ient s at aut opsy (35,168,237,277). T hey are usually asy mpt omat ic inc ident al f indings (361). Less f requent ly , t hey present w it h an abdominal mass or pain. Rupt ure and hemorrhage are report ed in up t o 25% in some series (139). Anemia, t hromboc y t openia, and a c onsumpt iv e c oagulopat hy (Kasabac h- Merrit t sy ndrome) hav e been not ed (226,285). Port al hy pert ension w it h esophageal v aric es also has been inf requent ly report ed (240,316). Splenic hemangiomas c an be mult iple or oc c ur w it h hemangiomas in ot her organs (F ig. 14- 15 and 14- 16). T hey hav e been desc ribed in assoc iat ion w it h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2132

14 - Spleen Klippel- T renaunay - Weber sy ndrome (c ut aneous hemangioma, v enous v aric osit ies, sof t t issue and bony hy pert rophy of an ext remit y ) (225). T hey range in size f rom a f ew millimet ers t o ov er 15 c m (266). In rare

c irc umst anc es, dif f use hemangiomat osis may oc c ur, in w hic h t he ent ire spleen may be replac ed by hemangioma (204). T his t y pe of inv olv ement is f requent ly ac c ompanied by angiomas in ot her hemat opoiet ic organs as w ell as by hemat ologic abnormalit ies (169). In t he spleen, c av ernous hemangiomas are more c ommon t han c apillary - t y pe hemangiomas (169,199).

F igure 14- 15 Splenic hemangioma. Cont rast - enhanc ed c omput ed t omography sc an show s a solit ary hy perenhanc ing lesion. (Case c ourt esy of John K. Mc Larney , Armed F orc es Inst it ut e of Pat hology .)

T he imaging c harac t erist ic s of splenic hemangiomas are similar t o t hose in t he liv er. On unenhanc ed CT , t hey appear as a w ell- def ined hy podense mass t hat may c ont ain c y st ic c omponent s. Wit h c ont rast injec t ion, most lesions enhanc e f rom t he periphery w it h gradual f ill in and persist enc e of c ont rast enhanc ement on delay ed images. Some lesions, how ev er, may remain hy podense, show dif f use enhanc ement , or show disc ret e mot t led areas of densit y (85,95,204,225,232,250,266). Clearly def ined peripheral disc ont inuous nodular enhanc ement seen w it h liv er hemangioma is unc ommon, oc c urring in only 2 of 22 pat ient s in P.985 one series using MRI and gadolinium (257). Calc if ic at ion c an oc c ur as sc at t ered, punc t at e, c urv ilinear densit ies, or as dense ray s radiat ing f rom a c ent ral point (127,225,266). On MR, t hese lesions appear hy point ense or, less

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2133

14 - Spleen c ommonly , isoint ense w it h respec t t o t he rest of t he spleen on T 1- w eight ed images and hy perint ense on T 2- w eight ed sequenc es. Het erogeneous signal is somet imes not ed on T 2- w eight ed images, ref lec t ing t he presenc e of c y st ic and solid c omponent s w it h v ary ing amount s of f ibrosis, nec rosis, and hemorrhage (85,232,250,257). Injec t ion of IV Gd- DT PA c auses enhanc ement similar t o t hat observ ed w it h iodinat ed c ont rast mat erial on CT (257). 99mT c —labeled red blood c ell (RBC) sc int igraphy w it h early and delay ed

single phot on emission c omput ed t omography (SPECT ) v iew s has been used t o c onf irm t he suspec t ed diagnosis of splenic hemangioma in a manner similar t o it s use w it h liv er hemangioma (360).

F igure 14- 16 Splenic hemangiomat osis. Cont rast - enhanc ed c omput ed t omography sc an show s mult iple poorly def ined hy podense splenic nodules. T he pat ient w as also not ed t o hav e a mediast inal hemangioma.

Littoral Cell Angioma Lit t oral c ell angioma is an unusual v asc ular t umor unique t o t he spleen. It is t hought t o be deriv ed f rom t he lining (lit t oral) c ells of t he splenic red pulp sinuses and henc e show s bot h endot helial and mac rophage c harac t erist ic s (91,169). T he lesion has no age or sex predilec t ion. Pat ient s may be asy mpt omat ic or present w it h splenomegaly . Hy persplenism w it h assoc iat ed t hromboc y t openia and anemia has been report ed, as has f ev er of unknow n origin and port al hy pert ension (91,306). Alt hough t he lesion it self is benign, an assoc iat ion w it h ot her malignanc ies has been report ed (66). T his assoc iat ion,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2134

14 - Spleen how ev er, may ref lec t t he w idespread use of CT in st aging malignanc y rat her t han a c ausat iv e role (169,207). On CT , t he lesions are usually mult iple, ranging f rom 0.2 t o 9 c m in diamet er and of low at t enuat ion (F ig. 14- 17) (91,119,306).

F igure 14- 17 Lit t oral c ell angioma. T he pat ient had adenoc arc inoma of t he lung. Splenec t omy perf ormed t o rule out met ast at ic disease or ly mphoma inv olv ing t he spleen rev ealed lit t oral c ell angioma. Inc ident al not e is made of renal at rophy sec ondary t o Alport sy ndrome.

Lymphangiomas Alt hough most c ommon in t he nec k and axilla, ly mphangiomas oc c ur rarely in t he abdominal v isc era. Disseminat ed ly mphangiomat osis af f ec t ing mult iple areas also has been report ed (16,239,347). Ly mphangiomas are c at egorized as c apillary , c av ernous, or c y st ic , depending on t he size of t he abnormal ly mphat ic c hannels. In t he spleen, t he c y st ic t y pe is most c ommon. Splenic ly mphangiomas are usually asy mpt omat ic or disc ov ered as a lef t upper quadrant mass. Ly mphangiomas c an oc c ur as single or mult iple lesions (199,349). CT may demonst rat e a w ell- def ined, mult iloc ular c y st or mult iple, t hin- w alled, w ell- marginat ed c y st s of t en in a subc apsular loc at ion. Dif f use inv olv ement of t he spleen w it h c omplet e replac ement of t he normal splenic parenc hy ma has also been observ ed (20). No or only slight enhanc ement of t he sept at ions and c y st w alls is not ed af t er IV administ rat ion of c ont rast mat erial. CT at t enuat ion measurement s f rom t he c y st s v ary f rom 15 t o 35 HU (30,239,247,299,332). Curv ilinear c alc if ic at ions hav e also been not ed (239). Rarely , a solid lesion may be mimic ked if t he c y st s are small (163). T 2-

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2135

14 - Spleen w eight ed MR images display t he t y pic al high signal int ensit y of f luid w it h mult iple hy point ense sept ae usually w ell seen (141,299). T 1- w eight ed images usually show hy point ense c y st s, alt hough hy perint ensit y is oc c asionally seen if t here has been prior hemorrhage or t he c y st f luid is prot einac eous (30).

Splenic Hamartomas Splenic hamart omas (also c alled splenomas or nodular hy perplasia of t he spleen) are rare, benign splenic lesions (108,167,349). T hey are c omposed of an anomalous mixt ure of normal splenic element s w it h red pulp predominat ing. A mixt ure of red and w hit e pulp, or w hit e pulp predominat ing, oc c urs less c ommonly . Whet her t hey represent a dev elopment al anomaly , a neoplasm, or a post t raumat ic lesion is unc ert ain (349). Hamart omas oc c ur singly or, less c ommonly , as mult iple nodules (307). T heir diamet er ranges f rom less t han 1 c m t o great er t han 15 c m (198,307). Like most ot her benign splenic lesions, t hey are usually disc ov ered inc ident ally or as a result of mass- relat ed sy mpt omat ology . T hromboc y t openia and anemia hav e been report ed rarely , as has spont aneous rupt ure (140,198,364). Splenic hamart omas are report ed as a rare manif est at ion of t uberous sc lerosis (73,339). On CT , splenic hamart omas appear as w ell- c irc umsc ribed iso- or hy podense masses on prec ont rast images, w it h oc c asional lesions show ing c y st ic c omponent s (36,370). Calc if ic at ion has been observ ed (323,370). T hey usually show slow enhanc ement and f ill in af t er IV administ rat ion of c ont rast mat erial (F ig. 14- 18). Prolonged enhanc ement similar t o t hat seen w it h hemangiomas is of t en not ed and c an serv e t o dif f erent iat e hamart omas f rom ly mphomas (219). Lesions t hat are isodense t o normal spleen on bot h pre- and post c ont rast images also hav e been report ed (215). On unenhanc ed MR images, t he lesions are usually isoint ense on T 1- w eight ed images and het erogeneously P.986 P.987 hy perint ense on T 2- w eight ed images relat iv e t o t he bac kground spleen (36,219,257) (see F ig. 14- 18). Slow , dif f use, het erogeneous enhanc ement is not ed f ollow ing gadolinium injec t ion. On delay ed images, more unif orm and persist ent enhanc ement is not ed, of t en great er t han t hat of adjac ent normal spleen. Oc c asional areas of hy point ensit y are not ed on delay ed images t hat appear t o c orrespond t o c y st ic areas of nec rosis (257). Upt ake on 99mT c c olloid sc int igraphy as w ell as on heat - t reat ed c hromium- 51–labeled RBC

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2136

14 - Spleen

st udies has been report ed (220,320,323). T his may be usef ul in est ablishing a noninv asiv e diagnosis, but suc h ac t iv it y is not inv ariably present .

F igure 14- 18 Splenic hamart oma. A: Cont rast - enhanc ed c omput ed t omography sc an show s solit ary hy perenhanc ing lesions w it h areas of c ent ral hy poenhanc ement . B: T 1- w eight ed f ast low - angle shot (F LASH) image show s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2137

14 - Spleen

isoint ense mass in spleen. C : T 2- w eight ed half - F ourier ac quisit ion single- shot t urbo spin- ec ho image show s isoint ense mass in spleen. D: Early post gadolinium F LASH images show het erogeneously hy perenhanc ing mass in t he spleen. E: On delay ed F LASH images, lesion bec omes isoint ense t o t he remainder of t he spleen.

Inflammatory Pseudotumor Inf lammat ory pseudot umors are rare, benign lesions c onsist ing of a poly morphous inf lammat ory c ell inf ilt rat e w it h v ary ing amount s of granulomat ous reac t ion, f ibrosis, and nec rosis (272). T hey hav e been desc ribed in v irt ually ev ery organ sy st em, inc luding lung, esophagus, liv er, ly mph nodes, and spleen (349). T hey c an be asy mpt omat ic or present as a mass ac c ompanied by v ague c onst it ut ional sy mpt oms (e.g., f ev er, malaise). T heir et iology is unc ert ain, alt hough t here has been spec ulat ion t hat t hey hav e an inf ec t ious or aut oimmune origin. Most pat ient s w it h splenic inf lammat ory pseudot umor are adult s; how ev er, t he lesion has been desc ribed in c hildren as y oung as 4 y ears of age (167,274). Alt hough t he lesion is benign, inc rease in size during observ at ion has been not ed (202). In t he spleen, inf lammat ory pseudot umors appear as w ell- c irc umsc ribed, enc apsulat ed masses. T hey usually are solit ary , but mult iple lesions hav e been report ed in t he liv er and spleen (118,272). T hey range f rom 1.5 c m t o more t han 12 c m in diamet er (195,272). On CT , t hey appear as a het erogeneous hy podense mass (104,272). Peripheral c alc if ic at ion has been desc ribed (104). Af t er IV administ rat ion of c ont rast mat erial, het erogeneous enhanc ement may oc c ur, w it h t he lesion being hy podense or isodense w it h t he remainder of t he spleen (104,202,359,366). Persist ent areas of hy podensit y c orresponding t o regions of f ibrosis are of t en not ed (104,202,359,366). On MR, t he lesions hav e been desc ribed as bot h slight ly hy perint ense and hy point ense relat iv e t o normal spleen on T 1- w eight ed images (118,202). On T 2- w eight ed images, t he lesions hav e been desc ribed as bot h hy perint ense and hy point ense relat iv e t o normal spleen (118,366). Mild- t o- moderat e enhanc ement is not ed af t er IV administ rat ion of gadolinium (118). T he v ariat ion in desc ribed appearanc es may ref lec t t he underly ing hist ologic het erogeneit y of t hese lesions.

Extramedullary Hematopoiesis Ext ramedullary hemat opoiesis may also produc e f oc al t umorlike lesions in t he spleen, alt hough it more c ommonly produc es homogeneous enlargement

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2138

14 - Spleen (84,111). Alt hough usually assoc iat ed w it h signif ic ant underly ing hemat ologic disease, t hey hav e been report ed in pat ient s w it h only mild anemia (84). On enhanc ed CT , f oc al ext ramedullary hemat opoiesis appears as a hy podense mass relat iv e t o t he remainder of t he spleen (84,111). On MRI, lesions are

slight ly hy point ense on T 1- w eight ed imaging and hy perint ense on T 2- w eight ed images. T he lesions show ed progressiv e enhanc ement af t er bolus injec t ion of gadolinium and w ent f rom hy point ense relat iv e t o splenic parenc hy ma on early - phase gadolinium- enhanc ed images t o isoint ense on lat e images (F ig. 1419) (107). In one report , f oc al lesions of ext ramedullary hemat opoiesis did not produc e a def ec t on 99mT c - sulf ur c olloid sc ans (111). Suc c essf ul diagnosis of f oc al splenic ext ramedullary hemat opoiesis has been not ed w it h f ine needle aspirat ion (F NA) (13).

F igure 14- 19 Ext ramedullary hemat opoiesis. T 1- w eight ed f ast low - angle shot image af t er gadolinium administ rat ion show s mult iple hy poenhanc ing splenic nodules of v ary ing sizes.

Other Benign Splenic Tumors Ot her benign t umors are quit e rare and inc lude lipomas, f ibromas, and angiomy olipomas (35,87,168,365). T he lat t er hav e been observ ed bot h in pat ient s w it h and w it hout t uberous sc lerosis (11,317). Bot h lipomas and angiomy olipomas are suggest ed on CT and MRI by t he c harac t erist ic appearanc e of f at (F ig. 14- 20).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2139

14 - Spleen Malignant Splenic Tumors Lymphoma Primary splenic ly mphoma is rare and makes up less t han 1% of all ly mphomas

(F ig. 14- 21) (6,38,349). When it oc c urs, it is usually a non- Hodgkin ly mphoma (NHL). Alt hough small- c ell ly mphomas hav e been said t o be t he most c ommon hist ologic t y pe of primary splenic ly mphoma (303,349), sev eral st udies hav e show n a dif f use large c ell predominanc e (71,123,165). Lef t upper quadrant pain or disc omf ort w as t he most c ommon present ing sy mpt om. Sy st emic sy mpt oms of w eight loss, malaise, and f ev er w ere also f requent ly not ed (6,71,349). Alt hough splenic ly mphoma P.988 may be c onf ined by t he splenic c apsule, loc al ext ension w it h inv asion int o adjoining st ruc t ures has been report ed (F ig. 14- 22) (132,150). T he majorit y of lesions w ere eit her solit ary (and larger t han 5 c m) or mult iple masses of v ary ing size (great er t han 1 c m). On unenhanc ed CT , lesions w ere eit her slight ly hy podense or isodense t o adjac ent spleen. Calc if ic at ion w as unc ommon (71). F ollow ing IV administ rat ion of c ont rast , lesions remained hy podense relat iv e t o normal spleen. Very - low - densit y f oc i w ere not unc ommonly not ed, suggest ing areas of nec rosis or isc hemia. Rim enhanc ement w as rarely seen (71).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2140

14 - Spleen

F igure 14- 20 Splenic lipoma. Cont rast - enhanc ed c omput ed t omography sc an show s a w ell- def ined f at - densit y mass (ar r ow ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2141

14 - Spleen F igure 14- 21 Primary splenic ly mphoma, B c ell t y pe A: Cont rast - enhanc ed c omput ed t omography sc an show s a het erogeneous hy poenhanc ing mass w it h c ent ral nec rosis. B: On T 1- w eight ed magnet ic resonanc e (MR) image, t he mass is isoint ense t o t he normal spleen. C : On T 2- w eight ed MR image, t he mass is slight ly hy point ense relat iv e t o t he normal spleen. D: F ollow ing int rav enous administ rat ion of gadolinium, t he mass is het erogeneously hy point ense.

Sec ondary splenic inv olv ement in bot h Hodgkin and non- Hodgkin ly mphoma is f requent , w it h ly mphomas as a group being t he most c ommon splenic malignanc y . T he spleen is f requent ly inv olv ed by Hodgkin and non- Hodgkin ly mphoma at t he t ime of diagnosis. T he perc ent age v aries ac c ording t o c ell t y pe (349,365). Splenic inv olv ement in ly mphoma c an t ake sev eral f orms: (a) homogeneous enlargement , (b) miliary nodules, (c ) mult if oc al lesions great er t han 1 c m, and (d) a single solit ary mass (6,98,365) (F igs. 14- 23, 14- 24, 1425). P.989 As a general rule in non- Hodgkin ly mphoma, large- c ell ly mphomas produc e eit her solit ary or mult iple masses. Small c leav ed and mixed c ell t y pes and int ermediat e ly mphoc y t ic ly mphomas c ommonly produc e a miliary pat t ern. Low grade ly mphomas w it h assoc iat ed blood inv olv ement t y pic ally c ause homogeneous enlargement . Hodgkin disease c an c ause solit ary or mult iple masses or a miliary pat t ern (365). All t y pes of Hodgkin disease may inv olv e t he spleen, alt hough inv olv ement w it h t he ly mphoc y t e- predominant f orm is least c ommon (148,349,365).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2142

14 - Spleen F igure 14- 22 Int ermediat e- grade, large- c ell ly mphoma (B phenot y pe) w it h inv asion int o adjac ent st ruc t ures. Cont rast - enhanc ed c omput ed t omography sc an show s homogeneous inf ilt rat ing mass.

On CT , f oc al ly mphomat ous lesions t y pic ally show low er at t enuat ion t han normal splenic parenc hy ma. Lesions are usually homogeneous, but nec rosis of large lesions has been report ed and c an giv e an irregular c y st ic appearanc e (33,132). In a pat ient w it h ly mphoma- assoc iat ed f ev er, t his appearanc e may mimic a splenic absc ess. Radiologic ally v isible c alc if ic at ion is unusual but has been report ed in aggressiv e lesions and af t er t herapy (see F ig. 14- 23) (186). On unenhanc ed MR, f oc al lesions are f requent ly isoint ense c ompared w it h splenic parenc hy ma on T 1- and T 2- w eight ed images. Oc c asionally , lesions are low er in signal t han spleen on T 2- w eight ed images—a f eat ure t hat may be helpf ul in dist inguishing ly mphoma f rom met ast asis (208). Port ions of lesions c an also hav e eit her inc reased or dec reased signal int ensit y if nec rosis, hemorrhage, f ibrosis, and edema are present (126,217,218). T he use of IV c ont rast mat erial on MRI improv es it s abilit y t o det ec t f oc al splenic lesions (193). Lesions are t y pic ally low er signal on post c ont rast images t han bac kground spleen (208). Agent s spec if ic f or ret ic uloendot helial t issue may be usef ul f or MRI. Superparamagnet ic iron oxide has been show n t o improv e signif ic ant ly t he abilit y of MRI t o dist inguish normal spleen f rom dif f use splenic ly mphoma (356).

F igure 14- 23 Non- Hodgkin ly mphoma in t w o pat ient s. A: Splenomegaly w it h mult iple hy podense nodules and ext ensiv e ret roperit oneal adenopat hy (a) in a pat ient w it h small c leav ed- c ell ly mphoma. B: Mult iple larger hy podense nodules in a pat ient w it h mixed large- and small- c ell ly mphoma. Also not ed is an enlarged lef t ret roc rural ly mph node.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2143

14 - Spleen Alt hough f oc al lesions c an be seen w it h CT and MRI, neit her modalit y is ac c urat e f or st aging splenic ly mphoma. On CT , inv olv ement is of t en isodense w it h adjac ent normal spleen, or lesions are below t he resolv ing pow er of t he t ec hnique. T he report ed ac c urac y of CT as a predic t or of splenic inv olv ement by ly mphoma ranges f rom a low sensit iv it y and spec if ic it y of 30% and 71%, respec t iv ely (49,113,190), t o a high sensit iv it y and spec if ic it y of approximat ely 90% (310,311). T he low er f igures are more in line w it h ext ensiv e c linic al lit erat ure t hat demonst rat es t hat normal- size spleens f requent ly show mic rosc opic inv olv ement and t hat mildly t o moderat ely enlarged spleens are of t en uninv olv ed (94,130,148,155,365). How ev er, markedly enlarged spleens almost alw ay s show ly mphomat ous inv olv ement (50,270,340). MRI has similarly not prov ed suc c essf ul at st aging splenic ly mphoma. No

signif ic ant c hange has been not ed in T 1 or T 2 v alues f or spleens inv olv ed w it h ly mphoma (218,324,356). P.990 In a st udy c omparing MRI, CT , and US f or det ec t ing splenic inf ilt rat ion in pat ient s w it h Hodgkin and non- Hodgkin ly mphoma, MRI and US w ere bet t er t han CT in demonst rat ing inf ilt rat ion in pat ient s w it h Hodgkin ly mphoma, alt hough no major dif f erenc e w as not ed w it h NHL. All t hree imaging t ec hniques f ailed t o det ec t t he majorit y of c ases of NHL inf ilt rat ion (217).

F igure 14- 24 Non- Hodgkin ly mphoma. F aint ly hy podense nodules w it h sc at t ered punc t at e c alc if ic at ion (ar r ow s) are not ed in t he spleen in a pat ient w it h unt reat ed dif f use large- c ell ly mphoma. Not e ext ensiv e ret roperit oneal adenopat hy (a), w hic h also demonst rat es c alc if ic at ion (c urv ed arrow ). K,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2144

14 - Spleen Kidney . A: At t he lev el of t he superior mesent eric art ery t akeof f . B: At t he lev el of t he renal art eries.

Rec ent ly , t he use of f luorodeoxy gluc ose posit ron emission t omography (F DGPET ) has been proposed f or ident if y ing ly mphomat ous inv olv ement in t he spleen. A small st udy c omparing it w it h CT in sev en pat ient s show ed improv ed ac c urac y w it h F DG- PET (100%, v ersus 57% f or CT ) (262). F DG- PET w as also show n t o hav e a higher ac c urac y (97% v ersus 78%) in predic t ing splenic inv olv ement t han gallium- 67 in a st udy inv olv ing 32 pat ient s w it h Hodgkin Ly mphoma (261).

F igure 14- 25 Hodgkin disease. A: Splenomegaly w it h mult iple hy podense splenic nodules in a pat ient w it h nodular sc lerosing Hodgkin disease. B: Mult iple hy podense nodules in t he liv er and spleen in a pat ient w it h adv anc ed Hodgkin disease.

Angiosarcomas Malignanc ies arising f rom t he mesenc hy mal c omponent s of t he spleen oc c ur but are quit e rare (74,349,358). Most are t umors of v asc ular origin. Angiosar c om a (hemangiosarc oma, malignant hemangioendot helioma, endot helial sarc oma) ref ers t o t he f rankly malignant v ariet y , w hereas hem angioendot heliom a has been used t o ref er t o v asc ular t umors of borderline malignant pot ent ial (212,349,365). Most pat ient s w it h splenic angiosarc oma are older t han 40 y ears. No sex predilec t ion is not ed. Sy mpt oms inc lude abdominal pain, lef t upper quadrant mass, f ev er, w eight loss, anemia, P.991 and c onsumpt iv e c oagulopat hy (92,349). T he durat ion of sy mpt oms is usually short (169). Dist ant met ast ases are c ommon and t he prognosis is poor

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2145

14 - Spleen (212,349). Splenomegaly is not ed in t he v ast majorit y of pat ient s and splenic rupt ure is report ed t o oc c ur in approximat ely one quart er t o one t hird of pat ient s (14,92,212,296,358). On CT , suc h neoplasms generally appear as f oc al, rounded, or irregular areas of het erogeneous low at t enuat ion (176,296,326). Lesions range f rom 1 c m t o as large as 18 c m in diamet er (169). Cy st ic and nec rot ic areas may be ev ident w it hin t he mass. Ac ut e hemorrhage and hemosiderin deposit s may appear as areas of inc reased densit y (250). Ext ensiv e c alc if ic at ion has been report ed in one c ase (158). Het erogeneous enhanc ement , w hic h c an be marked, has also been seen (F ig.

14- 26) (158,250). On T 2- w eight ed MR images, lesions hav e been desc ribed as het erogeneously hy perint ense. T 1- w eight ed images show hy point ense t umor. Prior int rat umoral hemorrhage may also produc e inc reased T 1 signal (158). Hemosiderin deposit ion may produc e dec reased T 1 and T 2 signals (250). At angiography , mult iple v asc ular lakes hav e been observ ed, w hic h may mimic t he appearanc e of c av ernous hemangiomat a (159).

F igure 14- 26 Splenic angiosarc oma in t w o pat ient s. A: Large, part ially enhanc ed angiosarc oma of t he spleen. B: Irregular bright ly enhanc ing splenic lesion w it h t w o met ast ases not ed in t he liv er (ar r ow s). (Case c ourt esy of Emil Balt hazar, M.D., New Y ork, NY )

Angiosarc oma has been c aused by exposure t o T horot rast , a c olloidal suspension of t horium dioxide used unt il t he 1950s as an angiographic c ont rast agent (176). In t hese pat ient s, CT show s a st riking inc rease in t he at t enuat ion of t he splenic parenc hy ma result ing f rom c hronic ret ent ion of t he radiopaque mat erial in ret ic uloendot helial c ells of t he spleen. Alt hough T horot rast - assoc iat ed angiosarc oma has oc c urred muc h more c ommonly in t he liv er, a primary c ase in t he spleen has been report ed (176). Viny l c hloride and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2146

14 - Spleen arsenic exposure, alt hough assoc iat ed w it h hepat ic angiosarc oma, hav e not been show n t o predispose t o splenic angiosarc oma (32,259,365).

Other Malignant Splenic Tumors Ot her primary mesenc hy mal malignanc ies t hat hav e been report ed in t he spleen inc lude f ibrosarc oma, leiomy osarc oma, malignant t erat oma, and malignant f ibrous hist ioc y t oma (MF H) (199,349,358). T he CT appearanc e of t hese lesions is not spec if ic . MF H has been desc ribed as a large mass w it h ext ensiv e areas of nec rosis (39). Muc inous c y st adenoc arc inoma also has been report ed in t he spleen and is t hought t o arise f rom eit her inv aginat ed c apsular mesot helium or embry onic rest s of panc reat ic or ent eric t issue. On CT , muc inous c y st adenoc arc inoma has t he appearanc e of a large mult ic y st ic mass. Calc if ic at ion c an be observ ed (201).

Metastatic Disease Met ast at ic deposit s in t he spleen are unusual. T hey oc c ur most c ommonly f rom hemat ogenous spread. Alt hough t hey are almost alw ay s seen in pat ient s w it h w idespread c arc inoma (i.e., met ast asis t o t hree or more organs), isolat ed splenic met ast ases hav e been report ed (93,160,222,241,350,355). In aut opsy series, splenic met ast ases are not ed in approximat ely 1% t o 9% of pat ient s w it h c arc inoma (2,350). Of t hese, one t hird t o one- half are f ound only on mic rosc opic examinat ion (26,187,350). T he lac k of af f erent splenic ly mphat ic s, periodic c hanges in spleen size, f ilt ering of blood by liv er and lung, and immune surv eillanc e w it hin t he spleen hav e all been suggest ed t o explain t he relat iv e inf requenc y of gross splenic met ast asis (47,350). T he most c ommon primary sit es of splenic met ast ases are breast and lung (26,187). Melanoma has t he highest f requenc y of splenic inv olv ement on a per primary basis, w it h 34% of melanoma pat ient s show ing splenic met ast asis at aut opsy (26). Splenic met ast ases most f requent ly appear as mult iple nodules, alt hough dif f use inf ilt rat ion oc c urs in 8% t o 10% of af f ec t ed pat ient s (187). T he splenic deposit s are usually asy mpt omat ic .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2147

14 - Spleen

F igure 14- 27 Endomet rial c arc inoma met ast at ic t o t he spleen. Cont rast enhanc ed c omput ed t omography sc an demonst rat es a large, c omplex low densit y met ast asis.

P.992 On CT , nodular met ast ases appear as rounded, hy podense lesions (F ig. 14- 27 and 14- 28). Cy st ic lesions may oc c ur w it h met ast asis f rom ov ary , breast , endomet rium, and melanoma (47,99,166,241,250,337,355). Calc if ic at ion is unc ommon but does oc c ur in pat ient s w it h serous or muc inous c y st adenoc arc inomas (47,250). Perit oneal implant s in pat ient s w it h an ov arian, gast roint est inal, or panc reat ic c anc er c an c ause sc alloping of t he c apsular surf ac e of t he spleen (99). Direc t splenic inv asion is unusual but c an oc c ur f rom adjac ent primaries in t he st omac h, c olon, panc reas, or kidney (166,250). On MRI, met ast ases f rom c olorec t al c arc inoma hav e been desc ribed as hy point ense t o isoint ense relat iv e t o normal spleen on T 1- w eight ed images, hy point ense on T 2- w eight ed images, and hy poenhanc ing post gadolinium administ rat ion (355).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2148

14 - Spleen

F igure 14- 28 Carc inoma met ast at ic t o t he spleen. A: Small, low - densit y lesions in t he spleen w it h bilat eral adrenal met ast ases in a pat ient w it h squamous c ell c arc inoma of t he lung. B: Hy podense mass w it hin t he spleen w it h bilat eral adrenal masses in a pat ient w it h malignant melanoma. C : Complex mass in t he splenic hilum in a pat ient w it h ov arian c arc inoma.

Splenic Infection Splenic inf ec t ion c an oc c ur eit her as a single f oc us or as part of a dif f use or miliary proc ess. Alt hough splenic inf ec t ion is unc ommon, t he inc reasing prev alenc e of immunosuppression in c anc er, t ransplant , and ac quired immunodef ic ienc y sy ndrome (AIDS) pat ient s has plac ed a great er populat ion at risk (48,209). Splenic inf ec t ion is usually t he result of hemat ogenous disseminat ion, w it h predisposing primary inf ec t ions oc c urring in 68% of pat ient s in one series (62). In more rec ent rev iew s, t his rat e is signif ic ant ly low er, probably bec ause of more aggressiv e ant ibiot ic use (209). Endoc ardit is w as t he P.993

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2149

14 - Spleen most c ommon assoc iat ed inf ec t ion, oc c urring in 12% of pat ient s w it h splenic absc ess. Conv ersely , splenic absc ess is seen in about 5% of pat ient s w it h endoc ardit is (264). Ot her assoc iat ed inf ec t ions inc luded urinary t rac t

inf ec t ion, surgic al w ound inf ec t ion, appendic it is, and pneumonia (62). Absc ess in ot her organs oc c urs in 15% t o 20% of pat ient s (62,325). Direc t spread of inf ec t ion f rom adjac ent organs has been report ed in c ases of gast ric ulc er and c arc inoma, c arc inoma of t he desc ending c olon, and perihepat ic absc ess. Noninf ec t ious predisposing f ac t ors inc lude diabet es, immunosuppression, and sic kle c ell disease. Disrupt ion of t he normal splenic parenc hy ma by t rauma or inf arc t ion also predisposes t o subsequent inf ec t ion (48,62). Pat ient s w it h splenic absc ess present c linic ally w it h f ev er, leukoc y t osis, and pain. T he lat t er c an loc alize in eit her t he lef t upper quadrant or lef t side of t he c hest , or c an be ref erred t o t he shoulder (62,213). Alt hough t his present at ion is t y pic al f or a solit ary splenic absc ess in a normal host , t he immunosuppressed pat ient w it h mult iple splenic absc esses of t en show s no loc alizing signs (48). Splenomegaly is not ed on phy sic al examinat ion in about half of t he pat ient s w it h splenic absc ess (62). T he most c ommon organisms are St aphy loc oc c us and St r ept oc oc c us, eac h oc c urring in approximat ely 10% t o 20% of pat ient s. Esc her ic hia c oli and Salm onella are also f requent . Ot her report ed organisms inc lude Klebsiella, Pseudom onas, Ent er obac t er , and Bar t onella henselae (265,325). Anaerobic organisms are not ed in 5% t o 17% of pat ient s (62,209,213). My c obac t eria and Pneum oc y st is c ar inii inf ec t ion also oc c ur (59,231). Wit h t he inc reasing prev alenc e of immunosuppression, f ungal inf ec t ion has bec ome more f requent , and in some series now c auses approximat ely 25% of splenic absc esses (48,209). On CT , a splenic absc ess appears as a nonenhanc ing or hy poenhanc ing area of low er at t enuat ion (F igs. 14- 29 and 14- 30). T he rim of t he absc ess of t en is isodense t o t he surrounding spleen, but it may be enhanc ed w hen iodinat ed c ont rast mat erial is injec t ed IV (7,292). Alt hough IV administ rat ion of c ont rast medium usually aids in demonst rat ing splenic absc esses, lesions t hat are more easily seen on unenhanc ed st udies hav e been report ed (229). Some aut hors rec ommend perf ormanc e of bot h pre- and post c ont rast sc ans, part ic ularly w hen t he miliary absc esses t y pic al of f ungal or my c obac t erial inf ec t ion are suspec t ed (229). Size may v ary f rom less t han 1 c m, in t he pat ient w it h a mult if oc al or miliary absc ess, t o 14 c m in diamet er (7,19,48,325). F ungal and my c obac t erial inf ec t ion in t he spleen is most likely t o appear as a miliary , mult if oc al, or mult iloc ular proc ess (57,101,292) (F igs. 14- 31, 14- 32, 4- 33).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2150

14 - Spleen Whereas 64% of mult iloc ular absc esses hav e a f ungal et iology , uniloc ular

absc esses hav e a bac t erial et iology in 94% of c ases (209). Gas oc c asionally is not ed w it hin splenic absc esses, but usually is absent . Calc if ic at ion has been seen in t reat ed Candida mic roabsc ess and in lesions c aused by ot her f ungi (most not ably Hist oplasm osis), my c obac t eria, and Pneum ooc y st is c ar inii (96,97,179,291,292) (see F ig. 14- 33). Int rasplenic psuedoaneury sms, inf arc t s, and hemorrhage hav e been report ed w it h murine t y phus (a ric ket t sial inf ec t ion), presumably as a manif est at ion of sy st emic v asc ulit is (252).

F igure 14- 29 Splenic absc ess. Comput ed t omography sc an show s a hy podense mass w it hout rim enhanc ement . Aspirat e w as posit iv e f or ent erobac t eria.

T he ov erall sensit iv it y of CT f or splenic absc ess is signif ic ant ly higher t han t hat of US and radionuc lide sc int igraphy . It should be not ed, how ev er, t hat a CT sc an w it hout f oc al abnormalit y does not exc lude t he possibilit y of early inf ec t ion, part ic ularly in hemat ogenously disseminat ed f ungal disease (292). On MR, hepat osplenic c andidiasis appears as low signal on T 1- w eight ed and high signal on T 2- w eight ed images relat iv e t o t he normal splenic parenc hy ma (58,281). Af t er IV administ rat ion of gadolinium, t he lesions show no enhanc ement . T 2- w eight ed f at - suppressed imaging as w ell as early post c ont rast T 1- w eight ed spoiled gradient ec ho imaging appear t o be t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2151

14 - Spleen most sensit iv e MRI sequenc es f or det ec t ing lesions, ev en more sensit iv e t han c ont rast - enhanc ed CT (281,283).

F igure 14- 30 Splenomegaly w it h mult iple small f aint ly v isualized hy podense nodules in a pat ient w it h bruc ellosis.

F igure 14- 31 My c obac t erial inf ec t ion in t w o pat ient s. A: Comput ed t omography sc an (CT ) show s mult iple small, hy podense nodules in a pat ient w it h t uberc ulosis. Not e low - densit y port al adenopat hy (a). B: CT sc an show s innumerable t iny hy podensit ies in a pat ient w it h My c obac t er ium av ium int r ac ellular e c om plex inf ec t ion.

P.994

Splenic Trauma

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2152

14 - Spleen Please ref er t o Chapt er 21 (T horac oabdominal T rauma) f or a f ull disc ussion of splenic t rauma.

Miscellaneous Splenic Disorders Amyloidosis Amy loidosis result s f rom t he deposit ion of ext rac ellular f ibrillar mat erial in a w ide v ariet y of t issues and organs. It oc c urs c ommonly w it h mult isy st em inv olv ement , alt hough an unusual loc alized f orm is report ed. Sy st emic amy loidosis c an be div ided int o t w o main t y pes based on t he bioc hemist ry of t he amy loid f ibril. In t y pe AL (primary ) amy loidosis, t he amy loid prot ein is produc ed by a monoc lonal populat ion of plasma c ells, eit her w it h or w it hout c linic al signs of mult iple my eloma. In t y pe AA, or sec ondary amy loidosis, amy loid deposit ion is sec ondary t o c hronic inf lammat ory disease, suc h as rheumat oid art hrit is (37,156,170). Splenic inv olv ement oc c urs in bot h t y pes and usually is homogeneous and dif f use. Splenomegaly , how ev er, is unusual, oc c urring in only 4% t o 13% of pat ient s (156). F oc al t umorlike lesions in t he spleen also hav e been report ed and c an oc c ur as part of eit her sy st emic or loc alized disease (56,177). Splenic inv olv ement is usually asy mpt omat ic , alt hough pain, inf arc t ion, and hy posplenism hav e been not ed (154). Spont aneous splenic rupt ure has also been observ ed, ev en in normal- size spleens, and is f elt t o be sec ondary t o v asc ular and/or splenic c apsular f ragilit y f rom amy loid deposit ion (124,138,154,318) (F ig. 14- 34). Splenic rupt ure is f requent ly t he init ial manif est at ion of amy loidosis in t hese pat ient s (164).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2153

14 - Spleen F igure 14- 32 Hepat osplenic c andidiasis. A: T 2- w eight ed magnet ic resonanc e (MR) image (repet it ion t ime, 3,800 ms; ec ho t ime, 90 ms) show s mult iple, small high- signal- int ensit y lesions in liv er and spleen. B:

gadolinium–diet hy lene- t riamine pent a- ac et ic ac id- enhanc ed T 1- w eight ed MR image (repet it ion t ime, 130 ms; ec ho t ime, 4 ms; f lip angle, 80 degrees). Absc esses appear as mult iple, small hy point ense lesions. (Case c ourt esy of Dr. Susan M. Asc her, Georget ow n Univ ersit y .)

F igure 14- 33 Pneum oc y st is c ar inii inf ec t ion. A: Lesions init ially appear as mult iple hy podense nodules. B: Af t er 10 w eeks of t herapy , lesions show peripheral and some c ent ral c alc if ic at ion.

P.995 On CT , dif f usely dec reased splenic at t enuat ion and enhanc ement hav e been observ ed (156,196,313). F oc al masses are also hy podense and hy poenhanc ing w it h ill- def ined margins (177,313). Ext ensiv e splenic c alc if ic at ion w as report ed in a c ase of primary amy loidosis (152). On MR, dec reased signal int ensit y on T 2- w eight ed images has been report ed in c ases of splenic amy loidosis (196,253). Dec reased splenic upt ake on 99mT c - sulf ur c olloid imaging has been seen f requent ly w it h amy loid, and alt hough it does not alw ay s c orrelat e w it h anat omic imaging, it is f requent ly ac c ompanied by abnormal red c ell morphology c onsist ent w it h relat iv e f unc t ional hy posplenism (244).

Gamna-Gandy Bodies Gamna- Gandy bodies are small siderot ic nodules in t he spleen t hat c ont ain v ary ing amount s of hemosiderin, f ibrous t issue, and c alc ium. T hey oc c ur f ollow ing int raparenc hy mal pet ec hial hemorrhage and are most c ommonly assoc iat ed w it h port al hy pert ension (192). T hey are also report ed w it h port al

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2154

14 - Spleen or splenic v ein t hrombosis, hemoly t ic anemia, sec ondary hemoc hromat osis, paroxy smal noc t urnal hemoglobinuria, and f ollow ing blood t ransf usions (78).

T hey are t y pic ally not v isualized w it h CT but are seen w ell w it h MRI sec ondary t o t he paramagnet ic propert ies of t he deposit ed iron (273). T hey appear on all pulse sequenc es as small f oc i of signal v oid sc at t ered t hroughout t he spleen (F ig. 14- 35). T hey range in size f rom a f ew millimet ers up t o 1 c m in diamet er (78).

F igure 14- 34 Spont aneous splenic hemorrhage sec ondary t o amy loidosis. S, spleen; ar r ow , perisplenic hemat oma.

Gaucher Disease Gauc her disease is an aut osomal rec essiv e def ic ienc y of t he ly sosomal enzy me gluc oc erebrosidase. T y pe 1 Gauc her disease ac c ount s f or almost all c ases and has an approximat e prev alenc e of 1 in 50,000. It is t he most c ommon ly sosomal st orage disease and result s in t he ac c umulat ion w it hin mac rophages of gluc oc erebroside (a breakdow n produc t f rom c ell membranes) (77). Ac c umulat ion of t hese lipid- laden mac rophages (Gauc her c ells) oc c urs most c ommonly in t he liv er, spleen, bone marrow , and t o a lesser degree lung. Suc h ac c umulat ion result s in splenomegaly , w hic h c an be marked. T hromboc y t openia, anemia, hepat ic dy sf unc t ion, and bone inf arc t s and f rac t ures are not ed c omplic at ions. T he inc idenc e of ly mphoprolif erat iv e disease is also signif ic ant ly inc reased (29). F oc al nodules are report ed in 20%

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2155

14 - Spleen

t o 30% of c ases and c orrespond t o areas of v ary ing amount s of Gauc her c ells, f ibrosis, and areas of inf arc t ion (136,243,321). On CT , f oc al lesions are desc ribed as hy podense and hy poenhanc ing in c omparison t o t he remainder of t he spleen. On MR, lesions hav e a v aried appearanc e show ing bot h areas of inc reased and dec reased signal on T 2w eight ed images, w it h t he majorit y of lesions being hy point ense (136,243). A t arget like appearanc e, w it h a hy point ense c ent er and hy perint ense rim, has also been report ed on T 2- w eight ed imaging (136). On T 1- w eight ed images, lesions P.996 w ere iso- or slight ly hy point ense and hy poenhanc ing af t er gadolinium administ rat ion (136,243,321).

F igure 14- 35 Gamna- Gandy bodies. A: T 1- w eight ed image. B: T 1- w eight ed f at - sat urat ed post - gadolinium image show s mult iple areas of signal v oid t hroughout t he splenic parenc hy ma in t his pat ient w it h c irrhosis.

Hemochromatosis Hemoc hromat osis is c at egorized int o primary and sec ondary f orms. T he lat t er f orm, usually seen in pat ient s rec eiv ing mult iple blood t ransf usions or in pat ient s w it h diseases c ausing ext rav asc ular hemoly sis (degradat ion of damaged or def ec t iv e red c ells by t he ret ic uloendot helial sy st em), suc h as heredit ary spheroc y t osis or aut oimmune hemoly t ic anemia, c auses ret ic uloendot helial deposit ion of iron. T his deposit ion is most readily seen on MRI, on w hic h t he paramagnet ic propert ies of iron result in a marked dec rease in signal int ensit y in t he liv er and spleen part ic ularly on T 2- w eight ed spin ec ho and gradient ec ho sequenc es (F ig. 14- 36) (120,295,305). An inc rease in

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2156

14 - Spleen densit y on CT c an oc c asionally be apprec iat ed, alt hough CT is muc h less sensit iv e in t his regard (137,178). Primary hemoc hromat osis, c aused by inappropriat ely high iron absorpt ion f rom t he gast roint est inal t rac t , result s in

parenc hy mal iron deposit ion in t he liv er, panc reas, heart , and ot her organs. In t his set t ing, t he spleen is not usually inv olv ed; how ev er, primary hemoc hromat osis w hen sev ere, c an oc c asionally result in ret ic uloendot helial inv olv ement . Similarly w hen sev ere, sec ondary hemoc hromat osis c an oc c asionally c ause parenc hy mal iron deposit ion in ot her organs (137,178). Ery t hropoiet ic hemoc hromat osis, w hic h may dev elop in pat ient s w it h t halassemia major, also show s inc reased iron absorpt ion and may mimic t he iron dist ribut ion pat t ern seen w it h primary hemoc hromat osis (367). T he int rav asc ular hemoly sis c harac t erist ic of paroxy smal noc t urnal hemoglobinuria c ommonly result s in iron deposit ion in t he renal c ort ex, w it h t he liv er and spleen usually not inv olv ed unless t he pat ient has rec eiv ed mult iple t ransf usions (269).

F igure 14- 36 Sec ondary hemoc hromat osis. Iron deposit ion in t he ret ic uloendot helial sy st em has c aused loss of signal in bot h liv er and spleen on t his T 1- w eight ed magnet ic resonanc e image (repet it ion t ime, 140 ms; ec ho t ime, 4 ms; f lip angle, 80 degrees).

Peliosis Peliosis is a rare c ondit ion in w hic h mult iple, blood- f illed spac es f orm in t he liv er, spleen, and, rarely , ot her part s of t he ret ic uloendot helial sy st em. It has

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2157

14 - Spleen been assoc iat ed w it h t he use of anabolic st eroids and oral c ont rac ept iv es. It

is also seen in pat ient s w it h human immunodef ic ienc y v irus inf ec t ion or c hronic w ast ing st at es, alt hough it has also been not ed in ot herw ise healt hy pat ient s (52,251,319,331). An assoc iat ion w it h bac illary angiomat osis as w ell as immunosuppression in organ t ransplant at ion is not ed (254). Pat ient s are usually asy mpt omat ic , alt hough splenic rupt ure has been report ed in pat ient s w it h peliosis (52,319,331). On unenhanc ed CT , peliosis usually appears as small, hy podense lesions (189), w hic h oc c asionally c an c oalesc e t o f orm large, mult iloc ulat ed masses w it h w ell- def ined sept a (65). Enhanc ement v aries, w it h some lesions bec oming P.997 isodense and ot hers demonst rat ing no enhanc ement (65,189,251). On MR, t he lesions in peliosis hav e a v ariet y of signal c harac t erist ic s depending on t he st at e of c ont ained blood (189).

Sarcoid St udies using perc ut aneous splenic aspirat ion hav e demonst rat ed splenic inv olv ement in 24% t o 59% of pat ient s w it h sarc oidosis (279,314). Splenic sarc oidosis usually is asy mpt omat ic . How ev er, w it h marked inv olv ement , abdominal disc omf ort , f ev er, malaise, hy persplenism, and ev en rupt ure may oc c ur (157). T he present at ion and appearanc e of t he spleen may also mimic ly mphoma, result ing in unnec essary splenec t omy . In one rev iew of t he CT f indings in 59 pat ient s w it h sarc oidosis (351), marked splenic enlargement w as not ed in 6% of pat ient s, w it h mild t o moderat e splenomegaly seen in 27% (F ig. 14- 37). Hy podense nodules, c orresponding t o aggregat ed granulomat a, w ere seen in t he spleen in 15% of pat ient s (F ig. 14- 38). No peripheral enhanc ement is usually seen w it h sarc oid nodules. Punc t at e c alc if ic at ions are unc ommon but hav e been report ed (102). Coexist ent abdominal ly mphadenopat hy is not ed f requent ly in pat ient s w it h splenomegaly . T he c hest radiograph, how ev er, has been report ed t o be normal in 25% of pat ient s w it h splenomegaly or disc ret e nodules (351). Sarc oid w as not ed t o be a c ommon c ause of mult iple splenic nodules in bot h t he sy mpt omat ic and t he asy mpt omat ic pat ient in one st udy looking at all pat ient s present ing w it h f iv e or more splenic nodules (354). It should be not ed, how ev er, t hat t his st udy may not be applic able t o all populat ions bec ause of t he w ide geographic v ariat ion in t he prev alenc e of sarc oid. On f ollow - up examinat ion, t he presenc e of splenic nodules did not presage a w orsening of t he pat ient 's pulmonary disease (353).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2158

14 - Spleen

F igure 14- 37 Sarc oidosis w it h marked splenomegaly (S), paraaort ic , and port ac av al adenopat hy (a).

F igure 14- 38 Sarc oidosis w it h splenomegaly and mult iple hy podense nodules.

On MRI, splenic nodules c aused by sarc oid are t y pic ally hy point ense on all sequenc es and hy poenhanc ing relat iv e t o normal spleen. Lesions are best v isualized on T 2- w eight ed f at - suppressed or T 1- w eight ed early gadoliniumenhanc ed images (352).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2159

14 - Spleen Sickle Cell Anemia Pat ient s w it h sic kle c ell anemia usually hav e repeat ed episodes of splenic inf arc t ion t hat ev ent ually result in a shrunken spleen c ont aining dif f use, mic rosc opic deposit s of c alc ium and iron (F ig. 14- 39) (182) CT has been helpf ul in est ablishing t hat a f oc al area of upt ake of 99mT c - diphosphonat e seen in t he lef t upper abdomen on radionuc lide sc int igraphy is t he result of upt ake in a c alc if ied spleen rat her t han in a f oc us of ost eomy elit is in t he ov erly ing rib (235). On CT , t he spleen w ill t y pic ally be at rophic and may be densely P.998 c alc if ied (183). MRI show s diminished T 1 and T 2 signal int ensit y c onsist ent w it h hemosiderin and/or c alc ium deposit ion. Hy perint ense areas may be not ed on T 1- w eight ed images if inf arc t and hemorrhage are present (4).

F igure 14- 39 T iny c alc if ied inf arc t ed spleen (ar r ow ) in an adult w it h sic kle c ell anemia. G, st omac h; L, liv er.

Ac ut e splenic sequest rat ion c risis oc c urs predominant ly in c hildren as a result of blood pooling in t he spleen. T he c linic al present at ion is v aried f rom mild t o massiv e splenomegaly w it h c irc ulat ory c ollapse. Alt hough t he diagnosis is usually made on c linic al grounds w it h an abrupt drop in hemat oc rit and presenc e of splenomegaly , imaging st udies may be request ed. On c ont rast enhanc ed CT , t he spleen t y pic ally show s eit her mult iple peripheral nonenhanc ing low - densit y areas or larger more dif f use areas of low densit y

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2160

14 - Spleen

inv olv ing most of t he spleen (288). T hese low - at t enuat ion regions are t hought t o represent areas of subac ut e hemorrhage and show high signal on bot h T 1and T 2- w eight ed sequenc es (268). Splenic rupt ure also c an c omplic at e sic kle c ell disease and c an be readily diagnosed w it h CT (183).

Splenic Artery Aneurysm Splenic art ery aneury sm is t he most c ommon abdominal v isc eral art ery aneury sm. It s inc idenc e in aut opsy series generally has been 0.01% t o 0.2%, alt hough w hen spec if ic ally looked f or, t hey hav e been f ound in up t o 10% of aut opsies (24,44,278,302). T his lat t er f igure inc ludes lesions less t han 0.5 t o 1 c m in diamet er (24). Predisposing c ondit ions inc lude pregnanc y and mult iparit y , sy st emic and port al hy pert ension, and art eriosc lerot ic disease (1,44,75,304,329). Bec ause of t heir assoc iat ion w it h pregnanc y , splenic art ery aneury sms are signif ic ant ly more c ommon in w omen, w it h only 15% t o 20% being seen in men (1,329). Most aneury sms are sac c ular, and ov er 80% oc c ur in t he mid- and dist al t hird of t he splenic art ery (286,329). F iv e perc ent t o 40% are mult iple. Size ranges f rom less t han 1 c m t o 30 c m, w it h a mean bet w een 2 and 3 c m (1,329). Alt hough t he v ast majorit y of pat ient s are asy mpt omat ic , t he presenc e of a pulsat ile mass, lef t upper quadrant pain, and rupt ure hav e been report ed (1,44,304,329). Embolizat ion or resec t ion are rec ommended if t he aneury sm is f ound in pregnant w omen or w omen of c hildbearing age, is sy mpt omat ic , is great er t han 1.5 t o 2.0 c m in diamet er, or is inc reasing in size (1,5,17). Oc c asionally , a spec if ic c ause c an be c it ed f or t he dev elopment of splenic art ery pseudoaneury sms. Ac ut e and c hronic panc reat it is, penet rat ing gast ric ulc er, t rauma, and sept ic emboli hav e all been implic at ed (42,44,188,227,304). My c ot ic aneury sms inv olv ing t he int rasplenic branc hes of t he splenic art ery also hav e been report ed (15). On unenhanc ed CT , a low - densit y lesion w it h peripheral c alc if ic at ion is observ ed along t he c ourse of t he splenic art ery . When large, t here may be signif ic ant areas of het erogeneous at t enuat ion c orresponding t o areas of c lot and hemorrhage. On unenhanc ed MRI, het erogeneous signal c an be observ ed on T 1- and T 2- w eight ed sequenc es, again represent ing areas of f oc al c lot (151). A f low v oid is seen c orresponding t o t he perf used lumen of t he aneury sm. F ollow ing IV administ rat ion of c ont rast mat erial, on bot h MRI and CT , bright enhanc ement is observ ed unless t he lesion is t hrombosed (F ig. 1440) (42,151,334).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2161

14 - Spleen

F igure 14- 40 Splenic art ery aneury sm (A) in a pat ient w it h a hist ory of panc reat it is. Not e panc reat ic c alc if ic at ions (ar r ow heads). S, spleen.

Splenic Involvement in Pancreatitis T he spleen is loc at ed adjac ent t o t he panc reat ic t ail and is f requent ly inv olv ed in panc reat it is. In a st udy of 100 c onsec ut iv e pat ient s w it h panc reat it is, t he most c ommon splenic - assoc iat ed abnormalit ies w ere perisplenic f luid c ollec t ions (not ed in 58%), splenic v ein t hrombosis (19%), splenic inf arc t ion (7%), and subc apsular hemorrhage (2%) (203). Pseudoc y st s arising in t he t ail of t he panc reas adjac ent t o t he splenic hilum oc c asionally ext end beneat h t he splenic c apsule or ev en int o t he splenic parenc hy ma (F ig. 14- 41) (100,173,348). P.999 Alt hough many of t hese c ollec t ions w ill resolv e spont aneously or w it h perc ut aneous drainage, splenic rupt ure has been report ed (3,271,328). Inf arc t ion, subc apsular hemat oma, and splenic art ery pseudoaneury sm hav e also been report ed in pat ient s w it h c omplic at ed panc reat it is (100,173,188,203,345). T ransient splenic enlargement has been assoc iat ed w it h ac ut e panc reat it is, part ic ularly in sev ere c ases, presumably f rom st enosis or obst ruc t ion of t he splenic v ein (333).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2162

14 - Spleen

F igure 14- 41 Panc reat ic pseudoc y st (P) ext ending int o t he splenic parenc hy ma.

DIAGNOSTIC ISSUES Splenomegaly Conf usion somet imes arises as t o w het her a mass f elt in t he lef t upper abdomen t ruly represent s an enlarged spleen. In suc h c ases, CT , US, or MRI c an prov ide a def init e answ er as t o w het her t he spleen is enlarged or w het her t here is a separat e abdominal mass. When t he spleen is enlarged, it s v isc eral surf ac e of t en bec omes c onv ex as t he spleen assumes a more globular shape. When splenomegaly is present , t here of t en are c linic al or CT f indings t hat indic at e it s c ause. Neoplasm, absc ess, or c y st may be seen w it hin t he spleen. Abdominal ly mph node enlargement may suggest ly mphoma or sarc oidosis. Cirrhot ic pat ient s w it h splenomegaly based on port al hy pert ension of t en show c harac t erist ic alt erat ions in t he size and shape of t he liv er and prominenc e of t he v enous st ruc t ures in t he splenic hilum and gast rohepat ic ligament (see Chapt er 12). T he pat ient may hav e a c linic al hist ory of mononuc leosis, sic kle c ell anemia, or idiopat hic t hromboc y t openic purpura. Rarely , t he pat ient may show c linic al sy mpt oms of amy loid or Gauc her disease. In a st udy of 18 pat ient s w it h splenomegaly of unknow n et iology ref erred f or splenec t omy , 7

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2163

14 - Spleen w ere diagnosed w it h ly mphoma, 6 w it h benign hy persplenism, 4 w it h sarc oid, and 1 w it h Cast leman disease (45).

Solitary Splenic Mass Many of t he ent it ies disc ussed c an produc e a f oc al splenic mass. When t he lesion is c y st ic or low densit y , t he dif f erent ial diagnosis inc ludes c ongenit al c y st s as w ell as post t raumat ic and panc reat ic pseudoc y st s. Neoplasia, inc luding ly mphangioma and c y st ic or nec rot ic met ast asis, are also c onsidered. In t he appropriat e c linic al set t ing, a solit ary splenic absc ess or ec hinoc oc c al c y st w ould be list ed. If a lesion is t hought t o be solid, t he dif f erent ial diagnosis inc ludes hemangioma (t he most c ommon benign t umor), ly mphoma (t he most c ommon malignant lesion), and more unusual t umors suc h as splenic hamart oma, angiosarc oma, and met ast at ic disease. In most c ases, imaging f indings are not suf f ic ient ly dist inc t iv e t o allow a spec if ic diagnosis, alt hough some appearanc es c an be quit e suggest iv e, suc h as t he bright enhanc ement assoc iat ed w it h some angiosarc omas, t he c lassic al appearanc e of hemangioma, or upt ake on liv er spleen sc an seen w it h hamart oma. In ot her c ases f ine needle aspirat ion (disc ussed lat er) may be rev ealing.

Multiple Splenic Masses T he dif f erent ial diagnosis f or mult iple splenic masses is f airly broad. In a st udy of pat ient s hav ing great er t han f iv e splenic nodules, t he most c ommon ent it ies assoc iat ed w it h a sy mpt omat ic pat ient w ere ly mphoma, granulomat ous inf ec t ion, and sarc oid. In t he asy mpt omat ic pat ient , sarc oid, benign angiomat ous t umor, and met ast at ic disease w ere most c ommon (354). T hese result s (f rom t he sout heast ern Unit ed St at es) may v ary in ot her geographic loc at ions w here endemic f ungal inf ec t ion is more c ommon and sarc oid less f requent . Ot her rare ent it ies assoc iat ed w it h mult iple splenic nodules inc lude ext ramedullary hemat opoiesis, amy loid, Gauc her disease, drug reac t ion t o pheny t oin, and peliosis.

Splenic Infarcts Splenic inf arc t ion c an oc c ur w it h embolic disease of c ardiac or at herosc lerot ic origin and in pat ient s w it h art erit is, my eloprolif erat iv e disease, panc reat it is, panc reat ic mass, and sic kle c ell anemia (18,143,214). If t hey are small, splenic inf arc t s are f requent ly asy mpt omat ic . Large inf arc t s c an c ause lef t

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2164

14 - Spleen upper quadrant pain, f ev er, and diaphragmat ic irrit at ion. On CT , inf arc t s

c lassic ally appear as sharply marginat ed, low - densit y regions t hat are w edgeshaped, w it h t he base at t he splenic c apsule and t he apex t ow ard t he hilum (F ig. 14- 42) (18,290). Not unc ommonly , how ev er, inf arc t s appear as mult iple, poorly marginat ed, hy podense lesions, indist inguishable f rom ot her f orms of f oc al splenic P.1000 pat hology (18). When t he ent ire spleen is inf arc t ed, suc h as af t er oc c lusion or av ulsion of t he splenic art ery , t here is f ailure of c ont rast enhanc ement of all but t he parenc hy ma immediat ely subjac ent t o t he c apsule. T his peripheral enhanc ement , t he so- c alled rim sign, is t he result of persist ent art erial supply f rom c apsular v essels.

F igure 14- 42 Splenic inf arc t s. Inf arc t ion inv olv ing more t han half t he spleen. Not e preserv at ion of some c apsular enhanc ement (ar r ow ).

Diminished splenic parenc hy mal enhanc ement w it hout inf arc t ion also oc c urs in t he set t ing of prof ound hy pot ension (28). T his c an mimic splenic art erial disrupt ion af t er blunt abdominal t rauma. In t he set t ing of massiv e splenic inf arc t ion, gas bubbles c an appear, ev en in uninf ec t ed splenic parenc hy ma, and may c ause c onf usion w it h splenic absc ess f ormat ion (83). Splenic inf arc t ion also c an be seen w it h MRI. Hemorrhagic inf arc t s hav e a high signal int ensit y on bot h T 1- and T 2- w eight ed images (135).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2165

14 - Spleen Spontaneous Splenic Rupture Spont aneous splenic rupt ure has been assoc iat ed w it h splenomegaly suc h as might oc c ur w it h inf ec t ion (e.g. malaria [31,260] or mononuc leosis [12]) or w it h hemat ologic malignanc y (e.g. leukemia or ly mphoma [21,112]). Rupt ure

has also been report ed in normal- size spleens inv olv ed w it h amy loid (154,164) or malignanc y (21). More f oc al proc esses c an also c ause splenic rupt ure, inc luding inf ec t ion (19,209), f oc al t umor inv olv ement (199), sarc oidosis (216), and inv olv ement by a panc reat ic pseudoc y st (3,328). Ant ic oagulat ion w it h low - molec ular- w eight heparin has also been report ed t o be assoc iat ed w it h rupt ure (41,315). Alt hough rare, splenic rupt ure has been report ed in pat ient s w it h pat hologic ally unremarkable spleens (230), as w ell as in hist ologic ally normal ac c essory spleens (67).

SPLENIC BIOPSY AND ASPIRATION Perc ut aneous diagnost ic splenic needle aspirat ion and biopsy has been used in t he ev aluat ion of sarc oidosis and ly mphoma and t o ev aluat e f oc al lesions in t he spleen (153,248,279,280,297,298,314,369). Diagnost ic rat es are generally high (80% t o 90%), espec ially f or f oc al lesions (153,180,205). T he addit ion of f low c y t omet ry t o rout ine f ine- needle aspirat ion (F NA) biopsy has been report ed t o be helpf ul in prov iding a def init iv e diagnosis in ly mphoid and my eloprolif erat iv e disorders (369). T he c omplic at ion rat e w it h F NA (20 t o 22 gauge) is low (153,280,298,314). Core biopsy using a f ine needle (22- or 21gauge Surec ut ) has also been undert aken f or st aging of ly mphoma, w it h no signif ic ant c omplic at ions enc ount ered in 46 pat ient s (51). A ret rospec t iv e rev iew of 24 adult c ases of splenic c ore biopsy (18- , 19- and 20- gauge needles) perf ormed ov er a 10- y ear period show ed t w o major c omplic at ions, bot h of w hic h oc c urred during F NA of a v asc ular t umor and bot h of w hic h required splenec t omy f or c ont rol of bleeding (180). A st udy of 27 c hildren w ho underw ent US- guided c ore biopsies (18 t o 21 gauge) show ed no c omplic at ions (205). Mult iple report s hav e show n t hat splenic absc ess c an be t reat ed w it h aspirat ion or perc ut aneous drainage (27,61,175,180,209,248,325). T his proc edure may aid in splenic salv age (322).

REFERENCES

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2166

14 - Spleen 1. Abbas MA, St one WM, F ow l RJ, et al. Splenic art ery aneury sms: t w o dec ades of experienc e at May o c linic . Ann Vasc Sur g 2002; 16:442–449.

2. Abrams HL, Spiro R, Goldst ein N. Met ast ases in c arc inoma: analy sis of 1000 aut opsied c ases. Canc er 1950;3:74–85. 3. Adelekan MO, Nasmy t h DG, Joglekar VM. Ac ut e panc reat it is present ing as a c ase of splenic rupt ure. Hosp Med 2003;64:432–433. 4. Adler DD, Glazer GM, Aisen AM. MRI of t he spleen: normal appearanc e and f indings in sic kle- c ell anemia. AJR Am J Roent genol 1986;147:843–845. 5. Ahlgren LS, Beardmore HE. Solit ary epidermoid splenic c y st s: oc c urrenc e in sibs. J Pediat r Sur g 1984;19:56–58. 6. Ahmann DL, Kiely JM, Harrison EG Jr, et al Malignant ly mphoma of t he spleen: a rev iew of 49 c ases in w hic h t he diagnosis w as made at splenec t omy . Canc er 1966;19:461–469. 7. Allal R, Kast ler B, Gangi A, et al. Splenic absc esses in t y phoid f ev er: US and CT st udies. J Com put Assist T om ogr 1993;17:90–93. 8. Allen KB, Gay BB Jr, Skandalakis JE. Wandering spleen: anat omic and radiologic c onsiderat ions. Sout h Med J 1992;85:976–984. 9. Ambriz P, Munoz R, Quint anar E, et al. Ac c essory spleen c ompromising response t o splenec t omy f or idiopat hic t hromboc y t openic purpura. Radiology 1985;155:793–796 10. Ament a PS, Ament a PS II. T he anat omy of t he spleen. In Bow dler AJ, ed. T he spleen: st r uc t ur e, f unc t ion and c linic al signif ic anc e. London: Chapman and Hall Medic al; 1990:3–7. 11. Asay ama Y , F ukuy a T , Honda H, et al. Chronic expanding hemat oma of t he spleen c aused by angiomy olipoma in a pat ient w it h t uberous sc lerosis. Abdom Im aging 1998;23:527–530. 12. Asgari MM, Begos DG. Spont aneous splenic rupt ure in inf ec t ious mononuc leosis: a rev iew . Y ale J Biol Med 1997;70:175–182. 13. Aust in GE, Gilt man LI, Varma V, et al. My eloid met aplasia present ing as a splenic mass: report of a c ase w it h f ine- needle aspirat ion c y t ology . Diagn Cy t opat hol 2000;23:359–361. 14. Aut ry JR, Weit zner S. Hemangiosarc oma of spleen w it h spont aneous rupt ure. Canc er 1975;35:534–539. 15. Av ery GR, Wilsdon JB, Mit c hell L. Case report : CT and angiographic appearanc es of int rasplenic my c ot ic aneury sm. Clin Radiol 1991;44:271–272. 16. Av igad S, Jaf f e R, F rand M, et al. Ly mphangiomat osis w it h splenic inv olv ement . JAMA 1976;236:2315–2317.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2167

14 - Spleen

17. Babb RR. Aneury sm of t he splenic art ery . Ar c h Sur g 1976; 111:924–925. 18. Balc ar I, Selt zer SE, Dav is S, et al. CT pat t erns of splenic inf arc t ion: a c linic al and experiment al st udy . Radiology 1984;151:723–729. 19. Balt hazar EJ, Hilt on S, Naidic h D, et al. CT of splenic and perisplenic abnormalit ies in sept ic pat ient s. AJR Am J Roent genol 1985;144:53–56. 20. Barrier A, Lac aine F , Callard P, et al. Ly mphangiomat osis of t he spleen and 2 ac c essory spleens. Sur ger y 2002;131:114–116. 21. Bauer T W, Haskins GE, Armit age JO. Splenic rupt ure in pat ient s w it h hemat ologic malignanc ies. Canc er 1981;48:2729–2733. 22. Beahrs JR, St ephens DH. Enlarged ac c essory spleens: CT appearanc e in post splenec t omy pat ient s. AJR Am J Roent genol 1980; 135:483–486. 23. Bearss RW. Splenic - gonadal f usion. Ur ology 1980;16:277–279. 24. Bedf ord PD, Lodge B. Aneury sm of t he splenic art ery . Gut 1960;1:312–320. 25. Benf at t o G, Cat ania G, D'Urso GM, et al. Ac ut e abdomen due t o w andering spleen inf arc t ion: a c ase report . Chir It al 2003; 55:243–247. 26. Berge T . Splenic met ast ases: f requenc ies and pat t erns. Ac t a Pat hol Mic r obiol Sc and 1974;82:499–506. 27. Berkman WA, Harris SA Jr, Bernardino ME. Nonsurgic al drainage of splenic absc ess. AJR Am J Roent genol 1983;141:395–396. 28. Berland LL, Van Dy ke JA. Dec reased splenic enhanc ement on CT in t raumat ized hy pot ensiv e pat ient s. Radiology 1985;156:469–471. P.1001 29. Beut ler E. Gauc her's Disease. N Engl J Med 1991;325:1354–1360. 30. Bezzi M, Spinelli A, Pierleoni M, et al. Cy st ic ly mphangioma of t he spleen: US- CT - MRI c orrelat ion. Eur Radiol 2001;11: 1187–1190. 31. Blac k SR, T renholme GM, Rac enst elm M, et al. Spont aneous rupt ure of t he malarial spleen. Am J Med 2001;111:330–331. 32. Bloc k JB. Angiosarc oma of t he liv er f ollow ing v iny l c hloride exposure. JAMA 1974;229:53–54. 33. Bloom RA, F reund U, Perkes EH, et al. Ac ut e Hodgkin disease masquerading as splenic absc ess. J Sur g Onc ol 1981;17:279–282. 34. Bonakdarpour A. Ec hinoc oc c us disease: report of 112 c ases f rom Iran and a rev iew of 611 c ases f rom t he Unit ed St at es. Am J Roent genol Radium T her Nuc l Med 1967;99:660–667. 35. Bost ic k WL. Primary splenic neoplasm. Am J Pat hol 1945; 21:1143–1165.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2168

14 - Spleen 36. Brinkley AA, Lee JK. Cy st ic hamart oma of t he spleen: CT and sonographic f indings. J Clin Ult r asound 1981:136–138. 37. Brow ning MJ, Banks RA, T ribe CR, et al. T en y ears' experienc e of an amy loid c linic a c linic opat hologic al surv ey . Q J Med 1985; 54:213–227.

38. Brox A, Bishinsky JI, Berry G. Primary non- Hodgkin ly mphoma of t he spleen. Am J Hem at ol 1991;38:95–100. 39. Brunet on JN, Drouillard J, Rogopoulos A, et al. Ext raret roperit oneal abdominal malignant f ibrous hist ioc y t oma. Gast r oint est Radiol 1988;13:299–305. 40. Buehner M, Baker MS. T he w andering spleen. Sur g Gy nec ol Obst et 1992;175:373–387. 41. Burg MD, Dallara JJ. Rupt ure of a prev iously normal spleen in assoc iat ion w it h enoxaparin: an unusual c ause of shoc k. J Em er g Med 2001;20:349–352. 42. Burke JW, Eric kson SJ, Kellum CD, et al. Pseudoaneury sms c omplic at ing panc reat it is: det ec t ion by CT . Radiology 1986;161: 447–450. 43. Burrig KF . Epit helial (t rue) c y st s: pat hogenesis of t he mesot helial and soc alled epidermoid c y st of t he spleen. Am J Sur g Pat hol 1988;12:275–281. 44. Busut t il RW, Brin BJ. T he diagnosis and management of v isc eral art ery aneury sms. Sur ger y 1980;88:619–624. 45. Carr JA, Shuraf a M, Velanov ic h V. Surgic al indic at ions in idiopat hic splenomegaly . Ar c h Sur g 2002;137:64–68. 46. Carragher AM. One hundred y ears of splenogonadal f usion. Ur ology 1990;35:471–475. 47. Carringt on BM, T homas NB, Johnson RJ. Int rasplenic met ast ases f rom c arc inoma of t he ov ary . Clin Radiol 1990;41:418–420. 48. Caslow it z PL, Labs JD, F ishman EK, et al. T he c hanging spec t rum of splenic absc ess. Clin Im aging 1989;13:201–207. 49. Cast ellino RA, Hoppe RT , Blank N. Comput ed t omography , ly mphography , and st aging laparot omy : c orrelat ions in init ial st aging of Hodgkin disease. AJR Am J Roent genol 1984;143:37–41. 50. Cast ellino RA. Hodgkin disease: prac t ic al c onc ept s f or t he diagnost ic radiologist . Radiology 1986;159:305–310. 51. Cav anna L, Civ ardi G, F ornari F , et al. Ult rasonic ally guided perc ut aneous splenic t issue c ore biopsy in pat ient s w it h malignant ly mphomas. Canc er 1992;69:2932–2936. 52. Celebrezze JP Jr, Cot t rell DJ, Williams GB. Spont aneous splenic rupt ure due t o isolat ed splenic peliosis. Sout h Med J 1998; 91:763–764.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2169

14 - Spleen 53. Chan KC, Chang Y H. Ac ut e abdomen due t o t orsion of a pelv ic w andering spleen. J F or m os Med Assoc 2002;101:577–580. 54. Chang Y W, Kim Han BK, Y oon HK, et al. Mult idet ec t or- row CT appearanc e of ac ut e t orsion of w andering spleen in a c hild. Ac t a Radiol 2003;44:107. 55. Chaw la S, Boal DK, Dillon PW, et al. Splenic t orsion. Radiogr aphic s 2003;23:305–308. 56. Chen KT , F lam MS, Workman RD. Amy loid t umor of t he spleen. Am J Sur g Pat hol 1987;11:723–725. 57. Chew F S, Smit h PL, Barboriak D. Candidal splenic absc esses. AJR Am J Roent genol 1991;156:474. 58. Cho J- S, Kim EE, Varma DGK, et al. MR imaging of hepat osplenic c andidiasis superimposed on hemoc hromat osis. J Com put Assist T om ogr 1990;14:774–776. 59. Choi BI, Im J- G, Han MC, et al. Hepat osplenic t uberc ulosis w it h hy persplenism: CT ev aluat ion. Gast r oint est Radiol 1989;14: 265–267.

60. Choi Y H, Menken F A, Jac obson IM, et al. Rec urrent ac ut e panc reat it is: an addit ional manif est at ion of t he “ w andering spleen” sy ndrome.” Am J Gast r oent er ol 1996;91:1034–1038. 61. Chou Y - H, Hsu C- C, T iu C- M, et al. Splenic absc ess: sonographic diagnosis and perc ut aneous drainage or aspirat ion. Gast r oint est Radiol 1992;17:262–266. 62. Chun CH, Raf f MJ, Cont reras L, et al. Splenic absc ess. Medic ine (Balt im or e) 1980;59:50–65. 63. Churei H, Inoue H, Nakajo M. Int rapanc reat ic ac c essory spleen: c ase report . Abdom Im aging 1998;23:191–193. 64. Coc hlin DL. Splenic - gonadal f usion—t he ult rasound appearanc es. Clin Radiol 1992;45:290–291. 65. Coc hrane LB, F reson M. Peliosis of t he spleen. Gast r oint est Radiol 1991;16:83–84. 66. Collins GL, Morgan MB, T ay lor F M 3rd. Lit t oral c ell angiomat osis w it h poorly dif f erent iat ed adenoc arc inoma of t he lung. Ann Diagn Pat hol 2003;7:54–59. 67. Coot e JM, Ey ers PS, Walker A, et al. Int ra- abdominal bleeding c aused by spont aneous rupt ure of an ac c essory spleen: t he CT f indings. Clin Radiol 1999;54:689–691. 68. Curt is GM, Mov it z D. T he surgic al signif ic anc e of t he ac c essory spleen. Ann Sur g 1946;123:276–298.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2170

14 - Spleen 69. D'Alt orio RA, Cano JY . Upside- dow n spleen as c ause of suprarenal mass. Ur ology 1978;11:422–424.

70. Dac hman AH, Ros PR, Murari PJ, et al. Nonparasit ic splenic c y st s: a report of 52 c ases w it h radiologic - pat hologic c orrelat ion. AJR Am J Roent genol 1986;147:537–542. 71. Dac hman AH, Buc k JL, Krishnan J, et al. Primary non- Hodgkin's splenic ly mphoma. Clin Radiol 1997;53:137–142. 72. Dalpe C, Cunningham M. Wandering spleen as an asy mpt omat ic pelv ic mass. Obst et Gy nec ol 2003;101:1102–1104. 73. Darden JW, T eeslink R, Parrish A. Hamart oma of t he spleen: a manif est at ion of t uberous sc lerosis. Am Sur g 1975;41: 564–566. 74. DasGupt a T , Coombes B, Brasf ield RD. Primary malignant neoplasms of t he spleen. Sur g Gy nec ol Obst et 1965;120:947–960. 75. Dav e SP, Reis ED, Hossain A, et al. Splenic art ery aneury sm in t he 1990s. Ann Vasc Sur g 2000;14:223–229. 76. Dav idson LA, Reid IN. Int rahepat ic splenic t issue. J Clin Pat hol 1997;50:532–533. 77. de F ost M, Aert s JM, Hollak CE. Gauc her disease: f rom f undament al researc h t o ef f ec t iv e t herapeut ic int erv ent ions. Net h J Med 2003;61:3–8. 78. Dobrit z M, Nomay r A, Baut z W, et al. Gamna- Gandy bodies of t he spleen det ec t ed w it h MR imaging: a c ase report . Magn Reson Im aging 2001;19:1249–1251. 79. Dodds WJ, T ay lor AJ, Eric kson SJ, et al. Radiologic imaging of splenic anomalies. AJR Am J Roent genol 1990;155:805–810. 80. Donnelly LF , Emery KH, Bov e KE, et al. Normal c hanges in t he MR appearanc e of t he spleen during early c hildhood. AJR Am J Roent genol 1996;166:635–639. 81. Donnelly LF , F oss JN, F rush DP, et al. Het erogeneous splenic enhanc ement pat t erns on spiral CT images in c hildren: minimizing misint erpret at ion. Radiology 1999;210:493–497. 82. Dourt he O, Maquin P, Pradere B, et al. Splenic c y st : demonst rat ion of t he relat ionship bet w een subc apsular hemat oma and f alse c y st by imaging. Br J Radiol 1992;65:541–542. 83. Dow ner WR, Pet erson MS. Massiv e splenic inf arc t ion and liquef ac t iv e nec rosis c omplic at ing poly c y t emia v era. AJR Am J Roent genol 1993;161:79–80.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2171

14 - Spleen 84. Du E, Ov erst reet K, Zhou W, et al. F ine needle aspirat ion of splenic ext ramedullary hemat opoiesis present ing as a solit ary mass. A c ase report . Ac t a Cy t ol 2002;46:1138–1142. 85. Duddy MJ, Calder CJ. Cy st ic haemangioma of t he spleen: f indings on ult rasound and c omput ed t omography . Br J Radiol 1989;62:180–182. 86. Durgun V, Kapan S, Kapan M, et al. Primary splenic hy dat idosis. Dig Sur g 2003;20:38–41.

87. Easler RE, Dow lin WM. Primary lipoma of t he spleen. Report of a c ase. Ar c h Pat hol 1969;88:557–559. 88. Ehrlic h P, Jamieson CG. Nonparasit ic splenic c y st s: a c ase report and rev iew . Can J Sur g 1990;33:306–308. 89. Eraklis AJ, F iller RM. Splenec t omy in c hildhood: rev iew of 1413 c ases. J Pediat r Sur g 1972;7:382–388. P.1002 90. F aer MJ, Ly nc h RD, Lic ht enst ein JE, et al. T raumat ic splenic c y st s: radiologic - pat hologic c orrelat ion f rom t he Armed F orc es Inst it ut e of Pat hology . Radiology 1980;134:371–376. 91. F alk S, St ut t e HJ, F rizzera G. Lit t oral c ell angioma: a nov el splenic v asc ular lesion demonst rat ing hist ioc y t ic dif f erent iat ion. Am J Sur g Pat hol 1991;15:1023–1033 92. F alk S, Krishnan J, Meis JM. Primary angiosarc oma of t he spleen. A c linic opat hologic st udy of 40 c ases. Am J Sur g Pat hol 1993; 17:959–970. 93. F arias- Eisner R, Braly P, Berek JS. Solit ary rec urrent met ast asis of epit helial ov arian c anc er in t he spleen. Gy nec ol Onc ol 1993;48:338–341. 94. F arrer- Brow n G, Bennet t MH, Harrison CV, et al. T he diagnosis of Hodgkin's disease in surgic ally exc ised spleens. J Clin Pat hol 1972;25:294–300. 95. F errozzi F , Bov a D, Draghi F , et al. CT f indings in primary v asc ular t umors of t he spleen. AJR Am J Roent genol 1996;166:1097–1101. 96. F euerst ein IM, F ranc is P, Raf f eld M, et al. Widespread v isc eral c alc if ic at ions in disseminat ed Pneum oc y st is c ar inii inf ec t ion: CT c harac t erist ic s. J Com put Assist T om ogr 1990;14:149–151. 97. F ishman EK, Magid D, Kuhlman JE. Pneum oc y st is c ar inii inv olv ement of t he liv er and spleen: CT demonst rat ion. J Com put Assist T om ogr 1990;14:146–148. 98. F ishman EK, Kuhlman JE, Jones RJ. CT of ly mphoma: spec t rum of disease. Radiogr aphic s 1991;11:647–669.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2172

14 - Spleen 99. F ishman EK, Kaw ashima A. Inf ec t ions and dif f use diseases. Balt imore: Mosby , 1993:138–170.

100. F ishman EK, Soy er P, Bliss DF , et al. Splenic inv olv ement in panc reat it is: spec t rum of CT f indings. AJR Am J Roent genol 1995; 164:631–635. 101. F it zgerald EJ, Coblent z C. F ungal mic roabsc esses in immuno- suppressed pat ient s—CT appearanc es. Can Assoc Radiol J 1988;39:10–12. 102. F olz SJ, Johnson CD, Sw ensen SJ. Abdominal manif est at ions of sarc oidosis in CT st udies. J Com put Assist T om ogr 1995;19: 573–579. 103. F ow ler RH. Collec t iv e rev iew : Hy dat id c y st s of t he spleen. Int Abst r Sur g 1953;96:105–116. 104. F ranquet T , Mont es M, Aizc orbe M, et al. Inf lammat ory pseudot umor of t he spleen: ult rasound and c omput ed t omographic f indings. Gast r oint est Radiol 1989;14:181–183. 105. F ranquet T , Mont es M, Lec umberri F J, et al. Hy dat id disease of t he spleen: imaging f indings in nine pat ient s. AJR Am J Roent genol 1990;154:525–528. 106. F urukaw a H, Kosuge T , Kanai Y , et al. Epidermoid c y st in an int rapanc reat ic ac c essory spleen: CT and pat hologic f indings. AJR Am J Roent genol 1998;171:271. 107. Gabat a T , Kadoy a M, Mori A, et al. MR imaging of f oc al splenic ext ramedullary hemat opoiesis in poly c y t hemia v era: c ase report . Abdom Im aging 2000;25:514–516. 108. Garv in DF , King F M. Cy st s and nonly mphomat ous t umors of t he spleen. Pat hol Annu 1981;16:61–80. 109. Gay er G, Apt er S, Jonas T , et al. Poly splenia sy ndrome det ec t ed in adult hood: report of eight c ases and rev iew of t he lit erat ure. Abdom Im aging 1999;24:178–184. 110. Gay er G, Zissin R, Apt er S, et al. CT f indings in c ongenit al anomalies of t he spleen. Br J Radiol 2001;74:767–772. 111. Gellet t LR, Williams MP, Viv ian GC. F oc al int rasplenic ext ramedullary hemat opoiesis mimic king ly mphoma: diagnosis made using liv er- spleen sc int igraphy . Clin Nuc l Med 2001;26: 145–146. 112. Giagounidis AAN, Burk M, Mec kenst oc k G, et al. Pat hologic rupt ure of t he spleen in hemat ologic malignanc ies: t w o addit ional c ases. Ann Hem at ol 1996;73:297–302. 113. Gilbert T , Cast ellino RA. Crit ic al rev iew : t he spleen in Hodgkin disease: diagnost ic v alue of CT . Inv est Radiol 1986;21:437–439.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2173

14 - Spleen

114. Gilman RS, T homas RL. Wandering spleen present ing as ac ut e panc reat it is in pregnanc y . Obst et Gy nec ol 2003;101:1100–1102. 115. Gilmart in D. F amilial mult iple epidermoid c y st of t he spleen. Conn Med 1978;42:297–300. 116. Git haiga JW, Adw ok JA. Wandering spleen present ing as a right hy poc hondrial mass and int est inal obst ruc t ion. East Af r Med J 2002;79:450–452. 117. Glazer GM, Axel L, Goldber HI, et al. Dy namic CT of t he normal spleen. AJR Am J Roent genol 1981;137:343–346. 118. Glazer M, Lally J, Kanzer M. Inf lammat ory pseudot umor of t he spleen: MR f indings. J Com put Assist T om ogr 1992;16:980–983. 119. Goldf eld M, Cohen I, Loberant N, et al. Lit t oral c ell angioma of t he spleen: appearanc e on sonography and CT . J Clin Ult r asound 2002;30:510–513. 120. Gomori JM, Grossman RI, Drot t HR. MR relaxat ion t imes and iron c ont ent of t halassemic spleens: an in v it ro st udy . AJR Am J Roent genol 1998;150:567–569. 121. Gooding GAW. T he ult rasonic and c omput ed t omographic appearanc e of splenic lobulat ions: a c onsiderat ion in t he ult rasonic dif f erent ial of masses adjac ent t o t he lef t kidney . Radiology 1978;126:719–720. 122. Grisc om NT , Hargreav es HK, Sc hw art z MZ, et al. Huge splenic c y st in a new born: c omparisons w it h 10 c ases in lat er c hildhood and adolesc enc e. AJR Am J Roent genol 1977;129:889–891. 123. Grosskreut z C, T roy K, Cut t ner J. Primary splenic ly mphoma: report of 10 c ases using t he REAL c lassif ic at ion. Canc er Inv est 2002;20:749–753. 124. Gupt a R, Singh G, Bose SM, et al. Spont aneous rupt ure of t he amy loid spleen: a report of t w o c ases. J Clin Gast r oent er ol 1998; 26:161. 125. Hadar H, Gadot h N, Herskov it z P, et al. Short panc reas in poly splenia sy ndrome. Ac t a Radiol 1991;32:299–301. 126. Hahn PF , Weissleder R, St ark DD, et al. MR imaging of f oc al splenic t umors. AJR Am J Roent genol 1988;150:823–827. 127. Halgrimson CG, Rust ad DG, Zeligman BE. Calc if ied hemangioma of t he spleen. JAMA 1984;252:2959–2960. 128. Halpart B, Gy orkey F . Lesions observ ed in ac c essory spleens of 311 pat ient s. Am J Clin Pat hol 1959;31:165–168.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2174

14 - Spleen

129. Halv orsen RA, Dunnic k NR, T hompson WM. Cont rast agent enhanc ement in abdominal c omput ed t omography : ionic v s. nonionic agent s. Inv est Radiol 1984;19:S234–S243. 130. Hanc oc k SL, Sc idmore NS, Hopkins KL, et al. Comput ed t omography assessment of splenic size as a predic t or of splenic w eight and disease inv olv ement in laparot omy st aged Hodgkin's disease. Int J Radiat Onc ol Biol Phy s 1994;28:93–99. 131. Hansen S, Jarhult J. Ac c essory spleen imaging: Radionuc lide, ult rasound and CT inv est igat ions in a pat ient w it h t hromboc y t openia 25 y r af t er splenec t omy f or IT P. Sc and J Haem at ol 1986;37:74–77. 132. Harris NL, Aisenberg AC, Mey er JE, et al. Dif f use large c ell (hist ioc y t ic ) ly mphoma of t he spleen: c linic al and pat hologic c harac t erist ic s of t en c ases. Canc er 1984;54:2460–2467. 133. Hay w ard I, Mindelzeun RE, Jef f rey RB. Int rapanc reat ic ac c essory spleen mimic king panc reat ic mass on CT . J Com put Assist T om ogr 1992;16:984–985. 134. Herman T E, Siegel MJ. Poly splenia sy ndrome w it h c ongenit al short panc reas. AJR Am J Roent genol 1991;156:799–800. 135. Hess CF , Griebel J, Sc hmiedl U, et al. F oc al lesions of t he spleen: preliminary result s w it h f ast MR imaging at 1.5 T . J Com put Assist T om ogr 1988;12:569–574. 136. Hill Sç, Damaska BM, Ling A, et al. Gauc her disease: abdominal MR imaging f indings in 46 pat ient s. Radiology 1992;184:561–566. 137. Housman JF , Chezmar JL, Nelson RC. Magnet ic resonanc e imaging in hemoc hromat osis: ext rahepat ic iron deposit ion. Gast r oint est Radiol 1989;14:59–60. 138. Hurd WW, Kat holi RE. Ac quired f unc t ional asplenia: assoc iat ion w it h spont aneous rupt ure of t he spleen and f at al spont aneous rupt ure of t he liv er in amy loidosis. Ar c h Int er n Med 1980;140: 844–845. 139. Husni EA. T he c linic al c ourse of splenic hemangioma w it h emphasis on spont aneous rupt ure. Ar c h Sur g 1961;83:681–688. 140. Iozzo RV, Haas JE, Chard RL. Sy mpt omat ic splenic hamart oma: a report of t w o c ases and rev iew of t he lit erat ure. Pediat r ic s 1980; 66:261–265. 141. It o K, Murat a T , Nakanishi T . Cy st ic ly mphangioma of t he spleen: MR f indings w it h pat hologic c orrelat ion. Abdom Im aging 1995;20:82–84. 142. It o Y , Shimizu E, Miy amot o T , et al. Epidermoid c y st s of t he spleen oc c urring in sist ers. Dig Dis Sc i 2002;47:619–623.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2175

14 - Spleen 143. Iuliano L, Gurgo A, Gualdi G, et al. Suc c eeding onset of hepat ic , splenic , and renal inf arc t ion in poly art erit is nodosa. AJG Am J Roent genol 2000;:1837–1838. 144. Jelinek JS, St uart PL, Done SL, et al. MRI of poly splenia sy ndrome. Magn Reson Im aging 1989;7:681–686. P.1003 145. Jequier S, Hanquinet S, Lironi A. Splenogonadal f usion. Pediat r Radiol 1998;28:526.

146. Jones T C. Cest odes (T apew or m s), 3rd ed. New Y ork: Churc hill Liv ingst on, 1990:2155–2156. 147. Joshi SN, Wolv erson MK, Cusw ort h RB, et al. Complement ary use of c omput erized t omography and t ec hnet ium sc anning in t he diagnosis of ac c essory spleen. Dig Dis Sc i 1980;25:888–892. 148. Kadin ME, Glat st ein E, Dorf man RF . Clinic opat hologic st udies of 117 unt reat ed pat ient s subjec t ed t o laparot omy f or t he st aging of Hodgkin's disease. Canc er 1971;27:1277–1294. 149. Kaneko J, Sugaw ara Y , Mat sui Y , et al. Normal splenic v olume in adult s by c omput ed t omography . Hepat ogast r oent er ology 2002; 49:1726–1727. 150. Karpeh MS Jr, Hic ks DG, T orosian MH. Colon inv asion by primary splenic ly mphoma: a c ase report and rev iew of t he lit erat ure. Sur ger y 1992;111:224–227. 151. Kehagias DT , T zalonikos MT , Moulopoulos LA, et al. MRI of a giant splenic art ery aneury sm. Br J Radiol 1998;71:444–446. 152. Kennan N, Ev ans C. Case report : hepat ic and splenic c alc if ic at ions due t o amy loid. Clin Radiol 1991;44:60–61. 153. Keogan MT , F reed KS, Paulson EK, et al. Imaging- guided perc ut aneous biopsy of f oc al splenic lesions: updat e on saf et y and ef f ec t iv eness. AJR Am J Roent genol 1999;172:933–937. 154. Khan AZ, Esc of et X, Robert s KM, et al. Spont aneous splenic rupt ure—a rare c omplic at ion of amy loidosis. Sw iss Sur g 2003;9:92–94. 155. Kim H, Dorf man RF . Morphologic al st udies of 84 unt reat ed pat ient s subjec t ed t o laparot omy f or t he st aging of non- Hodgkin's ly mphomas. Canc er 1974;33:657–674. 156. Kim SH, Han JK, Lee KH, et al. Abdominal amy loidosis: spec t rum of radiologic al f indings. Clin Radiol 2003;58:610–620. 157. Kimbrell OC Jr. Sarc oidosis of t he spleen. N Engl J Med 1957;257:128–131.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2176

14 - Spleen 158. Kinoshit a T , Ishii K, Y ajima Y , et al. Splenic hemangiosarc oma w it h massiv e c alc if ic at ion. Abdom Im aging 1999;24:185–187. 159. Kishikaw a T , Numaguc hi Y , T okunaga M, et al. Hemangiosarc oma of t he spleen and liv er met ast ases: angiographic manif est at ions. Radiology 1977;123:31–35. 160. Klein B, St ein M, Kut en A, et al. Splenomegaly and solit ary spleen met ast asis in solid t umors. Canc er 1987;60:100–102. 161. Kobay ashi H, Kaw amot o S, T amaki T , et al. Poly splenia assoc iat ed w it h semiannular panc reas. Eur Radiol 2001;11:1639–1641. 162. Koehler RE, Ev ens RG. T he spleen. Philadelphia: WB Saunders, 1981:1064–1088.

163. Komat suda T , Ishida H, Konno K, et al. Splenic ly mphangioma: US and CT diagnosis and c linic al manif est at ions. Abdom Im aging 1999;24:414–417. 164. Kozic ky OJ, Brandt LJ, Lederman M, et al. Splenic amy loidosis: a c ase report of spont aneous splenic rupt ure w it h a rev iew of t he pert inent lit erat ure. Am J Gast r oent er ol 1987;82:582–587. 165. Kraus MD, F leming MD, Vonderheide RH. T he spleen as a diagnost ic spec imen: a rev iew of 10 y ears' experienc e at t w o t ert iary c are inst it ut ions. Canc er 2001;91:2001–2009. 166. Krause R, Larsen CR, Sc holz F J. Gast rosplenic f ist ula: c omplic at ion of adenoc arc inoma of st omac h. Com put Med Im aging Gr aph 1990;14:273–276. 167. Krishnan J, F rizzera G. T w o splenic lesions in need of c larif ic at ion: hamart oma and inf lammat ory pseudot umor. Sem in Diagn Pat hol 2003;20:94–104. 168. Krumbhaar EB. T he inc idenc e and nat ure of splenic neoplasm. Ann Clin Med 1927;5:833–860. 169. Kut ok JL, F let c her CDM. Splenic v asc ular t umors. Sem Diagn Pat hol 2003;20:128–139. 170. Ky le RA, Gert z MA. Sy st emic amy loidosis. Cr it Rev Onc ol Hem at ol 1990;10:49–87. 171. Labruzzo C, Harit opoulos KN, El T ay ar AR, et al. Post t raumat ic c y st of t he spleen: a c ase report and rev iew of t he lit erat ure. Int Sur g 2002;87:152–156. 172. Lac kner K, Brec ht G, Janson R, et al. [T he v alue of c omput er t omography in t he st aging of primary ly mph node neoplasms (aut hor t ransl).] Rof o 1980;132:21–30.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2177

14 - Spleen 173. Lankisc h PG. T he spleen in inf lammat ory panc reat ic disease. Gast r oent er ology 1990;98:509–516.

174. Lauf f er JM, Baer HU, Maurer CA, et al. Int rapanc reat ic ac c essory spleen. A rare c ause of panc reat ic mass. Int J Panc r eat ol 1999; 25:65–68. 175. Lerner RM, Spat aro RF . Splenic absc ess: perc ut aneous drainage. Radiology 1984;153:643–645. 176. Lev y DW, Rindsberg S, F riedman AC, et al. T horot rast - induc ed hepat osplenic neoplasia: CT ident if ic at ion. AJR Am J Roent genol 1986;146:997–1004. 177. Liu T - Y , Chen S- C, Wang L- Y , et al. Sy st emic amy loidosis present ing as splenic t umor. Gast r oint est Radiol 1991;16:137–138. 178. Long JA, Doppman JL, Nienhus AW, et al. Comput ed t omographic analy sis of bet a- t halassemic sy ndromes w it h hemoc hromat osis: pat hologic f indings w it h c linic al and laborat ory c orrelat ions. J Com put Assist T om ogr 1980;4:159–165. 179. Lubat E, Megibow AJ, Balt hazar EJ, et al. Ext rapulmonary Pneum oc y st is c ar inii inf ec t ion in AIDS: CT f indings. Radiology 1990; 174:157–160. 180. Luc ey BC, Boland GW, Maher MM, et al. Perc ut aneous nonv asc ular splenic int erv ent ion: a 10- y ear rev iew . AJR Am J Roent genol 2002;179:1591–1596. 181. Madia C, Lumac hi F , Veroux M, et al. Giant splenic epit helial c y st w it h elev at ed serum markers CEA and CA 19- 9 lev els: an inc ident al assoc iat ion? Ant ic anc er Res 2003;23:773–776. 182. Magid D, F ishman EK, Siegelman SS. Comput ed t omography of t he spleen and liv er in sic kle c ell disease. AJR Am J Roent genol 1984;143:245–249. 183. Magid D, F ishman EK, Charac he S, et al. Abdominal pain in sic kle c ell disease: t he role of CT . Radiology 1987;163:325–328. 184. Mant erola C, Vial M, Losada H, et al. Unc ommon loc at ions of abdominal hy dat id disease. T r op Doc t 2003;33:179–180. 185. Marani SA, Canossi GC, Nic oli F A, et al. Hy dat id disease: MR imaging st udy . Radiology 1990;175:701–706. 186. Mart i- Bonmat i L, Ballest a A, Chiriv ella M. Unusual present at ion of nonHodgkin ly mphoma of t he spleen. Can Assoc Radiol J 1989;40:49–50. 187. Mary mont JG Jr, Gross S. Pat t erns of met ast at ic c anc er in t he spleen. Am J Clin Pat hol 1963;40:58–66. 188. Mauro MA, Sc hiebler ML, Parker LA, et al. T he spleen and it s v asc ulat ure in panc reat it is: CT f indings. Am Sur g 1993;59:155–159.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2178

14 - Spleen 189. Mav es CK, Caron KH, Bisset GS 3rd, et al. Splenic and hepat ic peliosis: MR f indings. AJR Am J Roent genol 1992;158:75–76. 190. Mendenhall NP, Cant or AB, Williams JL, et al. Wit h modern imaging t ec hniques, is st aging laparot omy nec essary in pediat ric Hodgkin's disease? A Pediat ric Onc ology Group st udy . J Clin Onc ol 1993;11:2218–2225.

191. Miles KA, Mc Pherson SJ, Hay ball MP. T ransient splenic inhomogeneit y w it h c ont rast - enhanc ed CT : mec hanism and ef f ec t of liv er disease. Radiology 1995;194:91–95. 192. Minami M, It ai Y , Oht omo K, et al. Siderot ic nodules in t he spleen: MR imaging of port al hy pert ension. Radiology 1989;172:681–684. 193. Mirow it z SA, Brow n JJ, Lee J, et al. Dy namic gadolinium- enhanc ed MR imaging of t he spleen: normal enhanc ement pat t erns and ev aluat ion of splenic lesions. Radiology 1991;179:681–686. 194. Mishalany H, Mahnov ski V, Woolley M. Congenit al asplenia and anomalies of t he gast roint est inal t rac t . Sur ger y 1982;91:38–41. 195. Monf ort e- Munoz H, Ro JY , Manning JT Jr, et al. Inf lammat ory pseudot umor of t he spleen: report of t w o c ases w it h a rev iew of t he lit erat ure. Am J Clin Pat hol 1991;96:491–495. 196. Monzaw a S, T sukamot o T , Omat a K, et al. A c ase w it h primary amy loidosis of t he liv er and spleen: radiologic f indings. Eur J Radiol 2002;41:237–241. 197. Moore PJ, Haw kins EP, Galliani CA, et al. Splenogonadal f usion w it h limb def ic ienc y and mic rognat hia. Sout h Med J 1997;90: 1152–1155. 198. Morgenst ern L, Mc Caf f ert y L, Rosenberg J, et al. Hamart omas of t he spleen. Ar c h Sur g 1984;119:1291–1293. 199. Morgenst ern L, Rosenberg J, Geller SA. T umors of t he spleen. Wor ld J Sur g 1985;9:468–476. 200. Morgenst ern L. Nonparasit ic splenic c y st s: pat hogenesis, c lassif ic at ion, and t reat ment . J Am Coll Sur g 2002;194:306–314. 201. Morinaga S, Ohy ama R, Koizumi J. Low - grade muc inous c y st adenoc arc inoma in t he spleen. Am J Sur g Pat hol 1992;16: 903–908. 202. Moriy ama S, Inay oshi A, Kurano R. Inf lammat ory pseudot umor of t he spleen: report of a c ase. Sur g T oday 2000;30:942–946. 203. Mort ele KJ, Mergo PJ, T ay lor HM, et al. Splenic and perisplenic inv olv ement in ac ut e panc reat it is: det erminat ion of prev alenc e and morphologic helic al CT f eat ures. J Com put Assist T om ogr 2001;25:50–54. P.1004

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2179

14 - Spleen

204. Moss CN, Van Dy ke JA, Koehler RE, et al. Mult iple c av ernous hemangiomas of t he spleen: CT f indings. J Com put Assist T om ogr 1986;10:338–340. 205. Murac a S, Chait PG, Connolly BL, et al. US- guided c ore biopsy of t he spleen in c hildren. Radiology 2001;218:200–206. 206. Murray KF , Morgan A, Christ ie DL. Panc reat it is c aused by a w andering spleen. J Pediat r Gast r oent er ol Nut r 1994;18:486–489. 207. Musgrav e NJ, Williamson RM, O'Rourke NA, et al. T est and t eac h. Inc ident ally disc ov ered splenic v asc ular lesion. Lit t oral c ell angioma of t he spleen. Pat hology 2002;34:579–581. 208. Nagase LL, Semelka RC, Armao D. Spleen. In: Semelka RC, ed. Abdom inalpelv ic MRI. New Y ork: Wiley - Liss, 2002:491–526. 209. Nelken N, Ignat ius J, Skinner M, et al. Changing c linic al spec t rum of splenic absc ess: a mult ic ent er st udy and rev iew of t he lit erat ure. Am J Sur g 1987;154:27–34. 210. Nelson RC, Chezmar JL, Pet erson JE, et al. Cont rast - enhanc ed CT of t he liv er and spleen: c omparison of ionic and nonionic c ont rast agent s. AJR Am J Roent genol 1989;153:973–976. 211. Nemc ek AA Jr, Miller F H, F it zgerald SW. Ac ut e t orsion of a w andering spleen: diagnosis by CT and duplex Doppler and c olor f low sonography . AJR Am J Roent genol 1991;157:307–309. 212. Neuhauser T S, Derringer GA, T hompson LDR, et al. Splenic angiosarc oma: a c linic opat hologic and immunophenot y pic st udy of 28 c ases. Mod Pat hol 2000;13:978–987. 213. Ng KK, Lee T Y , Wan Y L, et al. Splenic absc ess: diagnosis and management . Hepat ogast r oent er ology 2002;49:567–571. 214. Nguy en VD. A rare c ause of splenic inf arc t and f leet ing pulmonary inf ilt rat es: poly art erit is nodosa. Com put Med Im aging Gr aph 1991;15:61–65. 215. Norow it z DG, Morehouse HT . Isodense splenic mass: hamart oma, a c ase report . Com put Med Im aging Gr aph 1989;13:347–350. 216. Nusair S, Kramer MR, Berkman N. Pleural ef f usion w it h splenic rupt ure as manif est at ions of rec urrenc e of sarc oidosis f ollow ing prolonged remission. Respir at ion 2003;70:114–117. 217. Ny man R, Rehn S, Glimelius B, et al. Magnet ic resonanc e imaging, c hest radiography , c omput ed t omography , and ult rasonagraphy in malignant ly mphoma. Ac t a Radiol 1987;28:253–262.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2180

14 - Spleen

218. Ny man R, Rhen S, Eric sson A, et al. An at t empt t o c harac t erize malignant ly mphoma in spleen, liv er and ly mph nodes w it h magnet ic resonanc e imaging. Ac t a Radiol 1987;28:527–533. 219. Oht omo K, F ukuda H, Mori K, et al. CT and MR appearanc es of splenic hamart oma. J Com put Assist T om ogr 1992;16:425–428. 220. Okada J, Y oshikaw a K, Uno K, et al. Inc reased ac t iv it y on radioc olloid sc int igraphy in splenic hamart oma. Clin Nuc l Med 1990;15: 112–115. 221. Okuda K, T aguc hi T , Ishihara K, et al. Int rasplenic pseudoc y st of t he panc reas. J Clin Gast r oent er ol 1981;3:37–41. 222. Okuy ama T , Oy a M, Ishikaw a H. Isolat ed splenic met ast asis of sigmoid c olon c anc er: a c ase report . Jpn J Clin Onc ol 2001; 31:341–345. 223. Ot a T , T ei M, Y oshioka A, et al. Int rapanc reat ic ac c essory spleen diagnosed by t ec hnet ium- 99m heat - damaged red blood c ell SPECT . J Nuc l Med 1997;38:494–495. 224. Ough Y D, Nash HR, Wood DA. Mesot helial c y st s of t he spleen w it h squamous met aplasia. Am J Clin Pat hol 1981;76:666–669. 225. Pakt er RL, F ishman EK, Nussbaum A, et al. CT f indings in splenic hemangiomas in t he Klippel- T renaunay - Weber sy ndrome. J Com put Assist T om ogr 1987;11:88–91. 226. Pampin C, Dev illers A, T reguier C, et al. Int rat umoral c onsumpt ion of indium- 111- labeled plat elet s in a c hild w it h splenic hemangioma and t hromboc y t openia. J Pediat r Hem at ol Onc ol 2000;22:256–258. 227. Pant ongrag- Brow n L, Suw anw ela N, Arjhansiri K, et al. Demonst rat ion on c omput ed t omography of t w o pseudoaneury sms c omplic at ing c hronic panc reat it is. Br J Radiol 1991;64: 754–757. 228. Parker LA, Mit t elst aedt CA, Mauro MA, et al. T orsion of a w andering spleen: CT appearanc e. J Com put Assist T om ogr 1984; 8:1201–1204. 229. Past akia B, Shaw ker T H, T haler M, et al. Hepat osplenic c andidiasis: w heels w it hin w heels. Radiology 1988;166:417–421. 230. Paulv annan S, Py e JK. Spont aneous rupt ure of a normal spleen. Int J Clin Pr ac t 2003;57:245–246. 231. Pedro- Bot et J, Marist any MT , Miralles R, et al. Splenic t uberc ulosis in pat ient s w it h AIDS. Rev Inf ec t Dis 1991;13:1069–1071. 232. Peene P, Wilms G, St oc kx L, et al. Splenic hemangiomat osis: CT and MR f eat ures. J Com put Assist T om ogr 1991;15:1070–1072. 233. Peoples WM, Moller JH, Edw ards JE. Poly splenia: a rev iew of 146 c ases. Pediat r Car diol 1983;4:129–137.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2181

14 - Spleen

234. Perez F ont an F J, Soler R, Sant os M, et al. Ac c essory spleen t orsion: US, CT and MR f indings. Eur Radiol 2001;11:509–512. 235. Perlmut t er S, Jac obst ein JG, Kazam E. Splenic upt ake of 99mT c diphosphonat e in sic kle c ell disease assoc iat ed w it h inc reased splenic densit y on c omput erized t ransaxial t omography . Gast r oint est Radiol 1977;2:77–79. 236. Piekarski J, F ederle MP, Moss AA, et al. CT of t he spleen. Radiology 1980;135:683–689. 237. Pines B, Rabinov it c h J. Hemangioma of t he spleen. Ar c h Pat hol 1942;33:487–503. 238. Pinkhas J, Djaldet t i M, de Vries A, et al. Dif f use angiomat osis w it h hy persplenism: splenec t omy f ollow ed by poly c y t hemia. Am J Med 1968;45:795–801. 239. Pist oia F , Markow it z SK. Splenic ly mphangiomat osis: CT diagnosis. AJR Am J Roent genol 1988;150:121–122. 240. Pit lik S, Cohen L, Hadar H, et al. Port al hy pert ension and esophageal v aric es in hemangiomat osis of t he spleen. Gast r oent er ology 1977;72:937–940. 241. Plac e RJ. Isolat ed c olon c anc er met ast asis t o t he spleen. Am Sur g 2001;67:454–457. 242. Polat P, Kant arc i M, Alper F , et al. Hy dat id disease f rom head t o t oe. Radiogr aphic s 2003;23:475–494; quiz 536–477. 243. Poll LW, Koc h J- A, v om Dahl S, et al. Gauc her disease of t he spleen: CT and MR f indings. Abdom Im aging 2000;25:286–289. 244. Pow sner RA, Simms RW, Chudnov sky A, et al. Sc int igraphic f unc t ional hy posplenism in amy loidosis. J Nuc l Med 1998; 39:221–223. 245. Prassopoulos P, Cav ouras D. CT assessment of normal splenic size in c hildren. Ac t a Radiol 1994;35:152–154. 246. Prassopoulos P, Daskalogiannaki M, Raissaki M, et al. Det erminat ion of normal splenic v olume on c omput ed t omography in relat ion t o age, gender and body habit us. Eur Radiol 1997;7: 246–248. 247. Py at t RS, Williams ED, Clark M, et al. CT diagnosis of splenic c y st ic ly mphangiomat osis. J Com put Assist T om ogr 1981;5: 446–448. 248. Quinn SF , v anSonnenberg E, Casola G, et al. Int erv ent ional radiology in t he spleen. Radiology 1986;161:289–291. 249. Qureshi MA, Haf ner CD. Clinic al manif est at ions of splenic c y st s: st udy of 75 c ases. Am Sur g 1965;31:605–608.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2182

14 - Spleen 250. Rabushka LS, Kaw ashima A, F ishman EK. Imaging of t he spleen: CT w it h supplement al MR examinat ion. Radiogr aphic s 1994;14: 307–332. 251. Radin DR, Kanel GC. Peliosis hepat is in a pat ient w it h human immunodef ic ienc y v irus inf ec t ion. AJR Am J Roent genol 1991; 156 91–92. 252. Radin R, Hirbaw i IA, Henderson RW. Splenic inv olv ement in endemic (murine) t y phus: CT f indings. Abdom Im aging 2001; 26:298–299. 253. Raf al RB, Jennis R, Kosov sky PA, et al. MRI of primary amy loidosis. Gast r oint est Radiol 1990;15:199–201.

254. Raghav an R, Alley S, T aw f ik O, et al. Splenic peliosis: a rare c omplic at ion f ollow ing liv er t ransplant at ion. Dig Dis Sc i 1999;44: 1128–1131. 255. Ragozzino MW, Singlet ary H, Pat ric k R. F amilial splenic epidermoid c y st . AJR Am J Roent genol 1990;155:1233–1234. 256. Raissaki M, Prassopoulos P, Daskalogiannaki M, et al. Ac ut e abdomen due t o t orsion of w andering spleen: CT diagnosis. Eur Radiol 1998;8:1409–1412. 257. Ramani M, Reinhold C, Semelka RC, et al. Splenic hemangiomas and hamart omas: MR imaging c harac t erist ic s of 28 lesions. Radiology 1997;202:166–172. 258. Rat haus V, Zissin R, Goldberg E. Spont aneous rupt ure of an epidermoid c y st of spleen: preoperat iv e ult rasonographic diagnosis. J Clin Ult r asound 1991;19:235–237. 259. Regelson W, Kim U, Ospina J, et al. Hemangioendot helial sarc oma of liv er f rom c hronic arsenic int oxic at ion by F ow ler's solut ion. Canc er 1968;21:514–522. 260. Ribordy V, Sc haller MD, Mart inet O, et al. Spont aneous rupt ure of t he spleen during malaria t reat ed w it h t ransc at het er c oil embolizat ion of t he splenic art ery . Int ensiv e Car e Med 2002;28:996. P.1005 261. Rini JN, Manalili EY , Hof f man MA, et al. F - 18 F DG v ersus Ga- 67 f or det ec t ing splenic inv olv ement in Hodgkin's disease. Clin Nuc l Med 2002;27:572–577. 262. Rini JN, Leonidas JC, T omas MB, et al. 18F - F DG PET v ersus CT f or ev aluat ing t he spleen during init ial st aging of ly mphoma. J Nuc l Med 2003;44:1072–1074. 263. Rizk GK, T ay y arah KA, Ghandur- Mnay mneh L. T he angiographic c hanges in hy dat id c y st s of t he liv er and spleen. Radiology 1971;99:303–309. 264. Robinson SL, Saxe JM, Luc as CE, et al. Splenic absc ess assoc iat ed w it h endoc ardit is. Sur ger y 1992;112:781–786; disc ussion 786–787.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2183

14 - Spleen 265. Rolain JM, Chanet V, Lauric hesse H, et al. Cat sc rat c h disease w it h ly mphadenit is, v ert ebral ost eomy elit is, and spleen absc esses. Ann N Y Ac ad Sc i 2003;990:397–403. 266. Ros PR, Moser RP Jr, Dac hman AH, et al. Hemangioma of t he spleen: radiologic - pat hologic c orrelat ion in t en c ases. Radiology 1987;162:73–77. 267. Rose V, Izukaw a T , Moes CAF . Sy ndromes of asplenia and poly splenia: a rev iew of c ardiac and non- c ardiac malf ormat ions in 60 c ases w it h spec ial ref erenc e t o diagnosis and prognosis. Br Hear t J 1975;37:840–852.

268. Roshkow JE, Sanders LM. Ac ut e splenic sequest rat ion c risis in t w o adult s w it h sic kle c ell disease: US, CT , and MR imaging f indings. Radiology 1990;177:723–725. 269. Roubidoux MA. MR of t he kidney s, liv er, and spleen in paroxy smal noc t urnal hemoglobinuria. Abdom Im aging 1994;19:168–173. 270. Ruef f er U, Sieber M, St emberg M, et al. Spleen inv olv ement in Hodgkin's ly mphoma: assessment and risk prof ile. Ann Hem at ol 2003;82:390–396. 271. Ry pens F , Dev iere J, Zalc man M, et al. Splenic parenc hy mal c omplic at ions of panc reat it is: CT f indings and nat ural hist ory . J Com put Assist T om ogr 1997;21:89–93. 272. Saf ran D, Welc h J, Rezuke W. Inf lammat ory pseudot umors of t he spleen. Ar c h Sur g 1991;126:904–908. 273. Sagoh T , It oh K, T ogashi K, et al. Gamna- Gandy bodies of t he spleen: ev aluat ion w it h MR imaging. Radiology 1989;172:685–687. 274. Sarker A, An C, Dav is M, et al. Inf lammat ory pseudot umor of t he spleen in a 6- y ear- old c hild: a c linic opat hologic st udy . Ar c h Pat hol Lab Med 2003;127:e127–e130. 275. Say eed S, Koniaris LG, Kov ac h SJ, et al. T orsion of a w andering spleen. Sur ger y 2002;132:535–536. 276. Sc hlesinger AE, Hildebolt CF , Siegel MJ, et al. Splenic v olume in c hildren: simplif ied est imat ion at CT . Radiology 1994;193:578–580. 277. Sc hot t enf eld LE, Wolf son WL. Cav ernous hemangioma of t he spleen. Ar c h Sur g 1937;35:867–877. 278. Seids JV, Hauser H. Aneury sm of t he splenic art ery . Radiology 1941;36:171–180. 279. Selroos O. F ine- needle aspirat ion biopsy of t he spleen in diagnosis of sarc oidosis. Ann N Y Ac ad Sc i 1976;278:517–521. 280. Selroos O, Koiv unen E. Usef ulness of f ine- needle aspirat ion biopsy of spleen in diagnosis of sarc oidosis. Chest 1983;83:193–195.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2184

14 - Spleen 281. Semelka RC, Shoenut JP, Greenberg HM, et al. Det ec t ion of ac ut e and

t reat ed lesions of hepat osplenic c andidiasis: c omparison of dy namic c ont rast enhanc ed CT and MR imaging. J Magn Reson Im aging 1992;2:341–345. 282. Semelka RC, Shoenut JP, Law renc e PH, et al. Spleen: Dy namic enhanc ement pat t erns on gradient - ec ho MR images enhanc ed w it h gadopent et at e dimeglumine. Radiology 1992;185:479–482. 283. Semelka RC, Kelekis NL, Sallah S, et al. Hepat osplenic f ungal disease: diagnost ic ac c urac y and spec t rum of appearanc es on MR imaging. AJR Am J Roent genol 1997;169:1311–1316. 284. Sener R, Alper H. Poly splenia sy ndrome: a c ase assoc iat ed w it h t ranshepat ic port al v ein, short panc reas, and lef t inf erior v ena c av a w it h hemiazy gous c ont inuat ion. Abdom Im aging 1994;19:64–66. 285. Shanberge JN, T anaka K, Gruhl MC. Chronic c onsumpt iv e c oagulopat hy due t o hemangiomat ous t ransf ormat ion of t he spleen. Am J Clin Pat hol 1971;56:723–729. 286. Shanley CJ, Shah NL, Messina LM. Common splanc hnic art ery aneury sms: splenic , hepat ic , and c eliac . Ann Vasc Sur g 1996; 10:315–322 287. Shef lin JR, Lee CM, Kret c hmar KA. T orsion of w andering spleen and dist al panc reas. AJR Am J Roent genol 1984;142:100–101. 288. Shet h S, Ruzal- Shapiro C, Piomelli S, et al. CT imaging of splenic sequest rat ion in sic kle c ell disease. Pediat r Radiol 2000;30: 830–833. 289. Shiels WE, Johnson JF , St ephenson SR, et al. Chronic t orsion of t he w andering spleen. Pediat r Radiol 1989;19:465–467. 290. Shirkhoda A, Wallac e S, Sokhandan M. Comput ed t omography and ult rasonography in splenic inf arc t ion. J Can Assoc Radiol 1985;36:29–33. 291. Shirkhoda A, Lopez- Berest ein G, Holbert JM, et al. Hepat osplenic f ungal inf ec t ion: CT and pat hologic ev aluat ion af t er t reat ment w it h liposomal amphot eric in B. Radiology 1986;159: 349–353. 292. Shirkhoda A. CT f indings in hepat osplenic and renal c andidiasis. J Com put Assist T om ogr 1987;11:795–798. 293. Shirkhoda A, F reeman J, Armin AR, et al. Imaging f eat ures of splenic epidermoid c y st w it h pat hologic c orrelat ion. Abdom Im aging 1995;20:449–451. 294. Sic a GT , Reed MF . Case 27: int rapanc reat ic ac c essory spleen. Radiology 2000;217:134–137.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2185

14 - Spleen 295. Siegelman ES, Mit c hell DG, Rubin R. Parenc hy mal v ersus ret ic uloendot helial iron ov erload in t he liv er: dist inc t ion w it h MR imaging. Radiology 1991;179:361–366.

296. Smit h VC, Eisenberg BL, Mc Donald EC. Primary splenic angiosarc oma: c ase report and lit erat ure rev iew . Canc er 1985;55: 1625–1627. 297. Soderst rom N. How t o use c y t odiagnost ic spleen punc t ure. Ac t a Med Sc and 1976;199:1–5. 298. Solbiat i L, Bossi MC, Bellot t i E, et al. F oc al lesions in t he spleen: sonographic pat t erns and guided biopsy . AJR Am J Roent genol 1983;140:59–65. 299. Solomou EG, Pat riarheas GV, Mpadra F A, et al. Asy mpt omat ic adult c y st ic ly mphangioma of t he spleen: c ase report and rev iew of t he lit erat ure. Magn Reson Im aging 2003;21:81–84. 300. Souparis A, Papaziogas B, Alexandrakis A, et al. An unusual c ase of ret roperit oneal ac c essory spleen w it h v asc ular supply direc t ly f rom t he aort a. Miner v a Chir 2002;57:513–515. 301. Spenc er JA, Golding SJ. Case of t he mont h: not anot her c ase of aort ic dissec t ion! Br J Radiol 1993;66:565–566. 302. Sperling L. Aneury sm of t he splenic art ery . Sur ger y 1940;8: 633–638. 303. Spier CM, Kjeldsberg CR, Ey re HJ, et al. Malignant ly mphoma w it h primary present at ion in t he spleen: a st udy of 20 pat ient s. Ar c h Pat hol Lab Med 1985;109:1076–1080. 304. St anley JC, F ry WJ. Pat hogenesis and c linic al signif ic anc e of splenic art ery aneury sms. Sur ger y 1974;76:898–909. 305. St ark DD. Hepat ic iron ov erload: Paramagnet ic pat hology . Radiology 1991;179:333–335. 306. St eensma DP, Moric e WG. Lit t oral c ell angioma assoc iat ed w it h port al hy pert ension and resec t ed c olon c anc er. Ac t a Haem at ol 2000;104:131–134. 307. St einberg JJ, Suhrland MJ, Valensi QJ. T he assoc iat ion of splenoma w it h disease. Lab Inv est 1985;52:65A. 308. St einmet z AP, Rappaport A, Nikolov G, et al. Splenogonadal f usion diagnosed by spleen sc int igraphy . J Nuc l Med 1997;38: 1153–1155. 309. St iris MG. Ac c essory spleen v ersus lef t adrenal t umor: c omput ed t omographic and abdominal angiographic ev aluat ion. J Com put Assist T om ogr 1980;4:534–544. 310. St rijk SP, Wagener DJ, Bogman MJ, et al. T he spleen in Hodgkin disease: diagnost ic v alue of CT . Radiology 1985;154:753–757.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2186

14 - Spleen 311. St rijk SP, Boet es C, Bogman MJ, et al. T he spleen in non- Hodgkin ly mphoma. Diagnost ic v alue of c omput ed t omography . Ac t a Radiol 1987;28:139–144. 312. Subramany am BR, Balt hazar EJ, Horii SC. Sonography of t he ac c essory spleen. AJR Am J Roent genol 1984;143:47–49. 313. Suzuki S, T akizaw a K, Nakajima Y , et al. CT f indings in hepat ic and splenic amy loidosis. J Com put Assist T om ogr 1986;10:332–334. 314. T aav it sainen M, Koiv uniemi A, Helminen J, et al. Aspirat ion biopsy of t he spleen in pat ient s w it h sarc oidosis. Ac t a Radiol 1987;28:723–725.

315. T ac c one F S, St arc JM, Sc ulier JP. Splenic spont aneous rupt ure (SSR) and hemoperit oneum assoc iat ed w it h low molec ular w eight heparin: a c ase report . Suppor t Car e Canc er 2003;11:336–338. 316. T ada S, Shin M, T akashima T . Dif f use c apillary hemangiomat osis of t he spleen as a c ause of port al hy pert ension. Radiology 1972;104:63–64. 317. T ang P, Alhindaw i R, F armer P. Case report : primary isolat ed angiomy olipoma of t he spleen. Ann Clin Lab Sc i 2001;31:405–410. P.1006 318. T anno S, Ohsaki Y , Osanai S, et al. Spont aneous rupt ure of t he amy loid spleen in a c ase of usual int erst it ial pneumonia. Int er n Med 2001;40:428–431. 319. T axy JB. Peliosis: a morphologic c uriosit y bec omes an iat rogenic problem. Hum Pat hol 1978;9:331–340. 320. T eat es CD, Seale DL, Allen MS. Hamart oma of t he spleen. Am J Roent genol Radium T her Nuc l Med 1972;116:419–422. 321. T erk MR, Esplin J, Lee K, et al. MR imaging of pat ient s w it h t y pe 1 Gauc her's disease: relat ionship bet w een bone and v isc eral c hanges. AJR Am J Roent genol 1995;165:599–604. 322. T hanos L, Dailiana T , Papaioannou G, et al. Perc ut aneous CT - guided drainage of splenic absc ess. AJR Am J Roent genol 2002; 179:629–632. 323. T hompson SE, Walsh EA, Cramer BC, et al. Radiologic al f eat ures of a sy mpt omat ic splenic hamart oma. Pediat r Radiol 1996;26: 657–660. 324. T homsen C, Josephsen P, Karle H, et al. Det erminat ion of T 1 and T 2 relaxat ion t imes in t he spleen of pat ient s w it h splenomegaly . Magn Reson Im aging 1990;8:39–42. 325. T ikkakoski T , Siniluot o T , Paiv ansalo M, et al. Splenic absc ess: imaging and int erv ent ion. Ac t a Radiol 1992;33:561–565.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2187

14 - Spleen 326. T iu CM, Chou Y H, Wang HT , et al. Epit helioid hemangioendot helioma of spleen w it h int rasplenic met ast asis: ult rasound and c omput ed- t omography appearanc e. Com put Med Im aging Graph 1992;16:287–290.

327. T onkin ILD, T onkin AK. Visc eroat rial sit us abnormalit ies: sonographic and c omput ed t omographic appearanc e. AJR Am J Roent genol 1982;138:509–515. 328. T orric elli P, Coriani C, Marc het t i M, et al. Spont aneous rupt ure of t he spleen: report of t w o c ases. Abdom Im aging 2001;26:290–293. 329. T rast ek VF , Pairolero PC, Joy c e JW, et al. Splenic art ery aneury sms. Sur ger y 1982;91:694–699. 330. T suc hiy a N, Sat o K, Shimoda N, et al. An ac c essory spleen mimic king a nonf unc t ional adrenal t umor: a pot ent ial pit f all in t he diagnosis of a lef t adrenal t umor. Ur ol Int 2000;65:226–228. 331. T suda K, Nakamura H, Murakami T , et al. Peliosis of t he spleen w it h int raperit oneal hemorrhage. Abdom Im aging 1993; 18:283–285. 332. T surui N, Ishida H, Morikaw a P, et al. Splenic ly mphangioma: report of t w o c ases. J Clin Ult r asound 1991;19:244–249. 333. T sushima Y , T amura T , T omioka K, et al. T ransient splenomegaly in ac ut e panc reat it is. Br J Radiol 1999;72:637–643. 334. Ueda J, Kobay ashi Y , Hara K, et al. Giant aneury sm of t he splenic art ery and huge v arix. Gast r oint est Radiol 1985;10:55–57. 335. Urban BA, F ishman EK. Helic al CT of t he spleen. AJR Am J Roent genol 1998;170:997–1003. 336. Uriart e C, Pomares N, Mart in M, et al. Splenic hy dat idosis. Am J T r op Med Hy g 1991;44:420–423. 337. Urrut ia M, Mergo PJ, Ros LH, et al. Cy st ic masses of t he spleen: radiologic - pat hologic c orrelat ion. Radiogr aphic s 1996;16:107–129. 338. Valls C, Mones L, Guma A, et al. T orsion of a w andering ac c essory spleen: CT f indings. Abdom Im aging 1998;23:194–195. 339. Van Heerden JA, Longo MF , Cardoza F , et al. T he abdominal mass in t he pat ient w it h t uberous sc lerosis. Surgic al implic at ions and report of a c ase. Ar c h Sur g 1967;95:317–319. 340. Veronesi U, Musumec i R, Pizzet t i F , et al. T he v alue of st aging laparot omy in non- Hodgkin's ly mphomas (w it h emphasis on t he hist ioc y t ic t y pe). Canc er 1974;33:446–459. 341. Vibhakar SD, Bellon EM. T he bare area of t he spleen: a c onst ant CT f eat ure of t he asc it ic abdomen. AJR Am J Roent genol 1984; 142:953–955.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2188

14 - Spleen 342. v on Sinner W, t e St rake L, Clark D, et al. MR imaging in hy dat id disease. AJR Am J Roent genol 1991;157:741–745. 343. v on Sinner WN, St ridbec k H. Hy dat id disease of t he spleen. Ult rasonography , CT and MR imaging. Ac t a Radiol 1992;33: 459–461. 344. Vossen PG, Van Hedent EF , Degry se HR, et al. Comput ed t omography of t he poly splenia sy ndrome in t he adult . Gast r oint est Radiol 1987;12:209–211.345.

345. Vy borny CJ, Merrill T N, Reda J, et al. Subac ut e subc apsular hemat oma of t he spleen c omplic at ing panc reat it is: suc c essf ul perc ut aneous drainage. Radiology 1988; 169:161–162. 346. Wadham BM, Adams PB, Johnson MA. Inc idenc e and loc at ion of ac c essory spleens. N Engl J Med 1981;304:1111. 347. Wadsw ort h DT , New man B, Abramson SJ, et al. Splenic ly mphangiomat osis in c hildren. Radiology 1997;202:173–176. 348. Wang SJ, Chen J- J, Changc hien C- S, et al. Sequent ial inv asions of panc reat ic pseudoc y st s in panc reat ic t ail, hepat ic lef t lobe, c audat e lobe and spleen. Panc r eas 1993;8:133–136. 349. Warnke RA, Weiss LM, Chan JKC, et al. T um or s of t he ly m ph nodes and spleen, t hird ed. Washingt on, DC: Armed F orc es Inst it ut e of Pat hology , 1995. 350. Warren S, Dav is AH. St udies on t umor met ast asis: t he met ast ases of c arc inoma t o t he spleen. Am J Canc er 1981;21:517–533. 351. Warshauer DM, Dumblet on SA, Molina PL, et al. Abdominal CT f indings in sarc oidosis: radiologic and c linic al c orrelat ion. Radiology 1994;192:93–98. 352. Warshauer DM, Semelka RC, Asc her SM. Nodular sarc oidosis of t he liv er and spleen: appearanc e on MR images. J Magn Reson Im aging 1994;4:553–557. 353. Warshauer DM, Molina PL, Hamman SM, et al. Nodular sarc oidosis of t he liv er and spleen: analy sis of 32 c ases. Radiology 1995;195:757–762. 354. Warshauer DM, Molina PL, Woraw at t anakul S. T he spot t ed spleen: CT and c linic al c orrelat ion in a t ert iary c are c ent er. J Com put Assist T om ogr 1998;22:694–702. 355. Weat hers BK, Modest o VL, Gordon D. Isolat ed splenic met ast asis f rom c olorec t al c arc inoma: report of a c ase and rev iew of t he lit erat ure. Dis Colon Rec t um 1999;42:1345–1348. 356. Weissleder R, Elizondo G, St ark DD, et al. T he diagnosis of splenic ly mphoma by MR imaging: v alue of superparamagnet ic iron oxide. AJR Am J Roent genol 1989;152:175–180.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2189

14 - Spleen 357. West c ot t JL, Kruf ky EL. T he upside- dow n spleen. Radiology 1972;105:517–521. 358. Wic k MR, Sc heit hauer BW, Smit h SL, et al. Primary nonly mphoret ic ular malignant neoplasm of t he spleen. Am J Sur g Pat hol 1982;6:229–242. 359. Wiernik PH, Rader M, Bec ker NH, et al. Inf lammat ory pseudot umor of spleen. Canc er 1990;66:597–600. 360. Wijay a J, Kapoor R, Roac h P. T c - 99m- labeled RBC sc int igraphy and splenic hemangioma. Clin Nuc l Med 2001;26:1022–1023. 361. Willc ox T M, Speer RW, Sc hlinkert RT , et al. Hemangioma of t he spleen: present at ion, diagnosis, and management . J Gast r oint est Sur g 2000;4:611–613. 362. Wilson ME. A w or ld guide t o inf ec t ions: disease, dist r ibut ion, diagnosis. New Y ork: Oxf ord Univ ersit y Press, 1991. 363. Winer- Muram HT , T onkin ILD, Gold RE. Poly splenia sy ndrome in t he asy mpt omat ic adult : c omput ed t omography ev aluat ion. J T hor ac Im aging 1991;6:69–71. 364. Wirbel RJ, Uhlig U, F ut t erer KM. Case report : splenic hamart oma w it h hemat ologic disorders. Am J Med Sc i 1996;311:243246. 365. Wolf BC, Neiman RS. Disor der s of t he spleen. Philadelphia: WB Saunders, 1989. 366. Y ano H, Imasat o M, Monden T , et al. Inf lammat ory pseudot umor of t he spleen: report of t w o c ases. Sur ger y 2003;133:349–350. 367. Y oon DY , Choi BI, Han MC, et al. MR f indings of sec ondary hemoc hromat osis: t ransf usional v s ery t hropoiet ic . J Com put Assist T om ogr 1994;18:416–419. 368. Y uan S, Vaughan M, Agof f SN. Lef t - sided splenorenal f usion w it h marked ext ramedullary hemat opoiesis and c onc urrent lit hium t oxic it y . A c ase report and rev iew of t he lit erat ure. Ar c h Pat hol Lab Med 2003;127:e1–e3. 369. Zeppa P, Pic ardi M, Marino G, et al. F ine- needle aspirat ion biopsy and f low c y t omet ry immunophenot y ping of ly mphoid and my eloprolif erat iv e disorders of t he spleen. Canc er 2003; 99:118–127. 370. Zissin R, Lishner M, Rat haus V. Case report : unusual present at ion of splenic hamart oma; c omput ed t omography and ult rasonic f indings. Clin Radiol 1992;45:410–411.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

Thi s pa ge i s i ntenti ona l l y l eft bl a nk. Remove thi s text from the ma nua l templ a te i f you wa nt i t compl etel y bl a nk.

15 - The Pancreas

2192

15 - The Pancreas 20

15 - The Pancreas Editors: Le e , Jose ph K. T. ; Sa ge l, Stua rt S. ; Sta nle y , Robe rt J. ; He ike n, Ja y P. Title : C ompute d Body Tomogra phy with MRI C orre la tion , 4th Edition Copy right В©2006 Lippinc ot t Williams & Wilkins > T able of Cont ent s > 15 - T he Panc reas

15 The Pancreas De sire e E. Morga n Robe rt J. Sta nle y

PANCREAS T he past 5 y ears hav e seen remarkable c hanges in t he perf ormanc e of c omput ed t omography (CT ) f or diseases of t he panc reas. As w it h all abdominal v isc eral imaging, t he majorit y of t hese c hanges inv olv e mult idet ec t or or mult islic e (314) helic al t ec hniques. Bec ause of mult iple det ec t or row s, helic al mult idet ec t or CT (MDCT ) unit s are muc h f ast er t han helic al single det ec t or CT (SDCT ) unit s (f iv e t o eight t imes) and hav e a higher z- axis resolut ion (283). Prec ise t iming and rapid sequenc e ac quisit ion allow mult iple abdominal imaging passes during MDCT examinat ions t o prov ide a c ombined angiographic and organ- direc t ed st udy at prec isely def ined c irc ulat ion phases (99). Mult iplanar t hree- dimensional ref ormat ions generat ed w it h MDCT t ec hniques allow prec ise ev aluat ion of peripanc reat ic relat ionships in a v ariet y of normal and disease st at es. How ev er, t he inc reased c apabilit ies and applic at ions of MDCT hav e led t o c rit ic al c onsiderat ion of issues onc e t aken f or grant ed. Most import ant ly , w hen t hinner image slic es are c hosen f or a MDCT dat a ac quisit ion and t he same signal t o noise rat io as f or t hic ker slic es is desired, inc reased t ube c urrent and radiat ion dose result . Wit h short er t emporal sc an ac quisit ions t he t iming, met hod, and dose of int rav enous (IV) c ont rast enhanc ement are c ruc ial. Bec ause high at t enuat ion oral c ont rast result s in degradat ion of nonaxial rec onst ruc t ed images, w at er is used f or oral c ont rast w hen CT angiography is t o be perf ormed. T he large dat a set s generat ed during MDCT of t he panc reas, of t en great er t han 500 images per pat ient , make w orkst at ion use mandat ory .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2193

15 - The Pancreas Contrast Issues As helic al CT t ec hniques dev eloped, a rev olut ion in c ont rast t iming f or ev aluat ion of t he panc reas oc c urred. In 1996, Lu et al. (196) f irst desc ribed

t he panc reat ic parenc hy mal phase of c ont rast enhanc ement (F ig. 15- 1) as t he period during w hic h t he panc reat ic parenc hy ma is most markedly enhanc ed. T his phase oc c urs bet w een 40 t o 70 sec onds af t er IV injec t ion of 150 c c low osmolar c ont rast medium at a rat e of 3 c c per sec ond. Wit h SDCT , t he breat hhold required f or t hin- sec t ion c ov erage t hrough t he panc reas usually requires t he majorit y of t his period. How ev er, w it h MDCT , t he same z- axis c ov erage area t hrough t he panc reas may require only 8 t o 12 sec onds w it h a f our- det ec t or ring sc anner. Wit h new er 16- or 32- det ec t or ring c onf igurat ions, proport ionat ely less t ime is required f or t he same anat omic c ov erage, making c onsiderat ion of c ont rast issues pert inent t o c apabilit ies of indiv idual sc anners. Comparison of earlier SDCT and MDCT report s in t he lit erat ure is c onf using due t o v ariabilit y in rat es and doses of IV c ont rast injec t ions, t iming of sc ans, and t ec hnic al paramet ers suc h as slic e t hic kness, det ec t or c onf igurat ion, and ev en sc an direc t ion (49,85,141,170,212,340,342). It is quit e likely t hat t he end of t he art erial phase in many SDCT examinat ions ov erlaps t he panc reat ic parenc hy mal phase in MDCT examinat ions. In general, t he rat e t hat IV c ont rast is administ ered det ermines w hen t he panc reat ic parenc hy mal phase oc c urs, and t he dose administ ered det ermines how long t he peak panc reat ic enhanc ement last s. Spec if ic ally , t he f ast er t he injec t ion rat e, t he higher t he peak panc reat ic enhanc ement and t he sooner it is reac hed. T he larger t he dose, t he higher t he peak and t he more c onst ant maint enanc e of t he peak (170,340). T he equat ion f or det ermining w hen peak panc reat ic enhanc ement oc c urs desc ribed by T ublin et al. (340) is helpf ul. T he init ial sc anning delay f or an indiv idual pat ient c an be c alc ulat ed by adding 10 sec onds (t he aort ic t ransf er t ime) t o t he injec t ion durat ion (c ont rast medium v olume div ided by injec t ion rat e) and t hen subt rac t ing one half t he panc reat ic sc anning t ime. In general, t hree c irc ulat ory phases of c ont rast may aid in diagnosis of panc reat ic disorders: t rue art erial phase (F ig. 15- 2), P.1008 w hen t here is bright enhanc ement w it hin t he aort a and v isc eral art eries prior t o v enous f illing; panc reat ic parenc hy mal phase, w hen maximal dif f erenc es in normally enhanc ing panc reat ic parenc hy ma v ersus hy pov asc ular t umors (F ig.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2194

15 - The Pancreas 15- 3) or nec rosis are best depic t ed; and port al v enous phase, w hen t he liv er parenc hy ma (F ig. 15- 4) and port omesent eric v enous sy st em are ideally enhanc ed. It is c rit ic al t o ev aluat e t he c irc ulat ory phases f or abnormalit ies

best depic t ed w it h a part ic ular phase t o av oid misint erpret at ion. F or example, an underf illed hepat ic v ein segment may be diagnosed as a pot ent ial hepat ic met ast asis during t he panc reat ic parenc hy mal phase in a pat ient w it h panc reat ic adenoc arc inoma and should be c onf irmed only af t er v iew ing t he port al v enous phase images (F ig. 15- 5). Bec ause t he desired goals f or c ont rast enhanc ement now v ary w it h t he t y pe of panc reat ic disease suspec t ed, more spec if ic rec ommendat ions f or SDCT and MDCT sc an t ec hniques are giv en in t he sec t ions t o f ollow .

F igure 15- 1 Normal panc reat ic phase c omput ed t omography (CT ). A: A 5- mm panc reat ic parenc hy mal phase CT image demonst rat es normal panc reat ic t ail post erior t o t he st omac h, ext ending t ow ards t he splenic hilum. Not e splenic v ein (ar r ow ) c oursing along dorsal aspec t of t he panc reas. B: Slight ly more c audal image show s normal c aliber main panc reat ic duc t (ar r ow ) in t he body . Not e panc reat ic parenc hy ma is t hinnest in t he nec k, ant erior t o t he port al c onf luenc e. Normal c aliber dist al c ommon bile duc t (ar r ow head) lies w it hin post erior port ion of panc reat ic head, bordered by sec ond port ion of duodenum

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2195

15 - The Pancreas t o t he right . C : Slight ly more c audal image show s c onf luenc e of main panc reat ic duc t and dist al c ommon bile duc t near ampulla. Not e f at plane separat ing right border of superior mesent eric v ein f rom panc reat ic parenc hy ma and unc inat e proc ess (ar r ow ) insinuat ing post erior t o mesent eric v essels.

Computed Tomography Techniques Wit h respec t t o t he ev aluat ion of a know n or suspec t ed panc reat ic mass, t he goals of CT are t o c onf irm t he diagnosis by det ec t ing and loc alizing t he mass and t o ev aluat e t he ext ent of disease in ant ic ipat ion of pot ent ial resec t ion. In t he c ase of panc reat ic adenoc arc inoma, exc lusion of hepat ic and perit oneal met ast ases and ev aluat ion of loc al ext ension of t umor int o t he peripanc reat ic t issues, ly mph nodes, and most import ant ly t he c rit ic al art erial (superior mesent eric art ery , c eliac axis, hepat ic art ery ) and v enous (superior mesent eric v ein, port al c onf luenc e, main port al v ein) st ruc t ures t o predic t resec t abilit y of t he lesion are desired. Wit h CT angiography (CT A), t he goal of preoperat iv e v asc ular mapping in pat ient s w ho are pot ent ial c andidat es t o undergo Whipple proc edure is t o c learly def ine t he angiographic map w it h an ac c urac y equal t o c lassic angiography and t o depic t t he relat ionship of t he mass t o pot ent ially inv aded v essels, at t empt ing t o dif f erent iat e bet w een abut ment and inv asion of v essels along t heir c ourse. Wit h axial images alone, narrow ing or c onst ric t ion of v essels may be dif f ic ult t o judge (97). In addit ion t o CT A, opt imal t ec hniques f or mass det ec t ion now inc lude t hin sec t ion sc anning in t he panc reat ic parenc hy mal phase, f ollow ed by sc anning t hrough t he ent ire abdomen and pelv is in t he port al v enous phase. Generally , a prec ont rast st udy t hrough t he panc reas t o loc alize t he area t o be st udied af t er IV c ont rast P.1009 enhanc ement is perf ormed w it h t hic ker sec t ion images. In t he c ase of f unc t ional neuroendoc rine t umors of t he panc reas, t he art erial phase helps t o ident if y hy perenhanc ing lesions, w hic h may be mult iple or loc at ed in a peripanc reat ic loc at ion. IV c ont rast must be giv en at a rat e of at least 3 c c per sec ond (ideally administ ered at a rat e of 5 c c per sec ond w henev er possible), w it h most c ent ers using 150 c c of a nonionic medium (300 mg of iodine per millilit er). Wat er is t he oral c ont rast agent of c hoic e w hen ev aluat ing f or panc reat ic mass (T ables 15- 1 and 15- 2).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2196

15 - The Pancreas

F igure 15- 2 Insulinoma in a 61- y ear- old w oman w it h hy perinsulinemia and negat iv e out side c omput ed t omography (CT ) sc an. A: Pre- int rav enous 5- mm CT image demonst rat es no c ont our alt ering mass; how ev er, a slight ly higher at t enuat ion f oc us is v isible (ar r ow ). B: Art erial phase c ont rast - enhanc ed 3mm CT image demonst rat es a c orresponding f oc al 1.2- c m hy perenhanc ing mass at t he body /t ail junc t ion. C : Port al v enous phase image demonst rat es diminished c onspic uit y of t he lesion. D: Endosc opic ult rasound (EUS) image show s w ell- def ined hy poec hoic round mass c orresponding t o CT image. (EUS image c ourt esy of Mohammed Eloubeidi, MD.)

T he adv ant ages of mult iple det ec t or ov er SDCT hinge on t he abilit y t o image t he panc reas in bot h t he panc reat ic and v enous phases w it h an adequat e number of t hin slic es during a c omf ort able breat hhold. T hese high- qualit y v olumet ric dat a set s are t hen post proc essed using t ec hniques suc h as v olume rendering (VR), maximum int ensit y projec t ions (MIPs), and c urv ed planar ref ormat ions (CPRs) (F ig. 15- 6). Wit h f our- slic e MDCT sc anners, t he slic e t hic kness is t y pic ally on t he order of 1.00 t o 1.50 mm but t he pit c h and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2197

15 - The Pancreas gant ry rot at ion t imes y ield relat iv ely slow t able speeds, and as a result

respirat ory misregist rat ion c an be problemat ic . Wit h six- t o t en- slic e sc anners, t he minimum slic e t hic kness is st ill on t he order of 1.00 t o 1.50 mm but t he t able speeds are c onsiderably f ast er and t he breat hhold durat ion short er. Wit h 16- slic e sc anners, t he minimum slic e t hic kness is 0.50 t o 0.75 mm y ielding dat a set s t hat P.1010 P.1011 P.1012 are isot ropic . Isot ropic resolut ion oc c urs w hen t he v oxel dimensions are equal in t he x- , y - , and z- axes. F or example, w hen a dat a set is ac quired w it h a display f ield- of - v iew of 360 mm, a mat rix size of 512 Г— 512 and a 0.625- mm slic e t hic kness, t he v oxel dimension are 360/512 = 0.703 mm in t he x- and y axes and 0.625 mm in t he z- axis (plus some inherent slic e broadening due t o t able mot ion). Wit h 32- t o 64- slic e sc anners, t he minimum v oxel dimensions are st ill on t he order of 0.50 t o 0.75 mm but t he t able speeds are muc h f ast er.

F igure 15- 3 Small panc reat ic adenoc arc inoma in a 63- y ear- old man w it h abdominal pain and biliary enzy me elev at ion. A: Panc reat ic parenc hy mal phase 2.5- mm c omput ed t omography (CT ) image t hrough t he panc reat ic head

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2198

15 - The Pancreas demonst rat es slight dilat at ion of t he v ert ic al port ion of t he main panc reat ic duc t and bile duc t in t he panc reat ic head region, near t he ampulla. B: More c audal panc reat ic parenc hy mal phase 2.5- mm CT image demonst rat es a f airly w ell- c irc umsc ribed 1- c m het erogeneous mass present at t he abrupt

t erminat ion of t he dilat ed bile duc t , seen immediat ely t o t he right and slight ly post erior t o t he v ert ic al panc reat ic duc t (ar r ow ). C : Same slic e port al v enous phase 5- mm CT image demonst rat es less c onspic uit y of t he lesion obst ruc t ing t he bile duc t . T he t umor w as resec t able.

F igure 15- 4 Small liv er met ast asis, and normal f at t y inf ilt rat ion of t he panc reas, making solid panc reat ic head adenoc arc inoma more obv ious. A: Cont rast - enhanc ed port al v enous phase 3- mm image demonst rat es normal f at t y replac ement and lobularit y of t he t ail and body . Het erogeneous low at t enuat ion solid appearing mass in t he superior head is readily apparent . B: Slight ly superior image t o A demonst rat es dilat ed main panc reat ic duc t in t he nec k and body . Het erogeneous mass abut s port al c onf luenc e and hepat ic art ery . C : Port al v enous phase c omput ed t omography image t hrough t he superior liv er rev eals a f oc al 8- mm hy podense liv er lesion c onsist ent w it h a met ast asis, indic at ing an inoperable t umor. TABLE 15- 1 MDC T F OR PANC REATIC MASS

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2199

15 - The Pancreas

Cont rast : IV—150 mL 4/sec , Oral—750–1,000 mL w at er. Art erial phase (AP): 20- sec delay f rom st art of injec t ion, F OV 20–25, 1.25 HS t able speed of 1 c m/sec (7.5 mm/0.8 sec ), c ov er f rom 1 c m abov e c eliac axis t o 3rd duodenum 3- D ref ormat ions using v olume rendering and/or MIP, w it h c urv ed planar rec onst ruc t ion along major v essels. Panc reat ic parenc hy mal phase (PPP): 35- sec delay , 2.5 mm w /5 mm rec on int erv al HQ, t able speed 1 c m/sec (7.5 mm/0.8), same c ov erage area, bot h AP and PPP ac quired during single breat hhold. 3- D ref ormat ions using v olume rendering and or c urv ed planar rec onst ruc t ion along duc t s. Port al v enous phase (PVP): 60- sec delay , larger F OV, diaphragm t o iliac c rest , 5- mm c ollimat ion w /5 mm rec on in HQ t able speed of 1 c m/sec (7.5 mm/0.8 sec ). 3- D, t hree- dimensional; F OV, f ield of v iew ; HQ, high qualit y ; HS, high speed; MDCT , mult idet ec t or c omput ed t omography ; MIP, maximum int ensit y projec t ion. TABLE 15- 2 SDC T F OR PANC REATIC MASS a Cont rast : IV—150 mL 3/sec , Oral—750–1,000 mL w at er. Panc reat ic parenc hy mal phase (PPP): 35–40 sec delay , 2.5 mm w it h 1.5–1.8 pit c h t o c ov er 1 c m abov e c eliac axis t o 3rd duodenum during single breat hhold, rec on t o 3 mm, w it h 3- D ref ormat ions using v olume rendering and or c urv ed planar rec onst ruc t ion along duc t s. Port al v enous phase (PVP): 70- sec delay , 7 mm f rom diaphragm t o c rest , if lengt h of breat hhold allow s, narrow t o 5 mm t hrough panc reas, 1:1 pit c h, larger F OV. a Must selec t eit her PPP or art erial phase, t o ac c ompany PVP due t o breat hhold requirement s f or c ov erage and c ont rast t iming issues. 3- D, t hree- dimensional; F OV, f ield of v iew ; SDCT , single det ec t or c omput ed t omography .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2200

15 - The Pancreas

F igure 15- 5 Small panc reat ic adenoc arc inoma in unc inat e, best seen on panc reat ic parenc hy mal phase. Liv er met ast ases best depic t ed on port al v enous phase. A: Panc reat ic parenc hy mal phase 2.5- mm image demonst rat es 1.2- c m mass in t he medial aspec t of t he unc inat e proc ess. T he mass abut s, but does not def orm, t he port al v ein (ar r ow ). B: Port al v enous phase image, same lev el, demonst rat es diminished c onspic uit y of t he mass. C : Art erial phase t hrough t he superior liv er demonst rat es lac k of opac if ic at ion w it hin t he hepat ic v eins. Not e rounded lesion similar in at t enuat ion in t he int erlobar area (ar r ow ). D: Port al v enous phase same lev el demonst rat es f illing of t he hepat ic v eins and great er c onspic uit y of t he liv er met ast asis in t his pat ient despit e v ery small panc reat ic mass at present at ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2201

15 - The Pancreas

F igure 15- 6 Curv ed planar ref ormat t ed image of normal panc reas. Wit h c ursor draw n along c ourse of t he main panc reat ic duc t , t he ent ire gland is v isualized, and t he relat ionship of t he panc reat ic duc t t o dist al c ommon bile duc t is w ell depic t ed.

Alt hough sc anners ac quiring 16 or more slic es per gant ry rot at ion are c apable of generat ing isot ropic dat a set s, t hese small v oxels may hav e an inherent and int olerable inc rease in image noise unless t he t ube c urrent (and t he c orresponding radiat ion dose) is signif ic ant ly boost ed. When nonisot ropic images are rec onst ruc t ed f rom isot ropic dat a set s (i.e., 2.50- t o 5.00- mm axial slic es or 2.00- t o 3.00- mm c oronal and sagit t al images), t he noise is reduc ed t o a t olerable lev el. How ev er, c ert ain t y pes of image rec onst ruc t ions, suc h as VR and CPR, display indiv idual v oxels and as a result of t en demonst rat e unac c ept able lev els of image noise. T heref ore, many inst it ut ions hav e c hosen t o address t his problem by ac quiring dat a set of t he panc reas (at least during t he panc reat ic phase of enhanc ement ) w it h nonisot ropic v oxels on t he order of 1.00 t o 1.50 mm. Alt hough t he spat ial resolut ion is low er, t he abilit y t o det ec t and c harac t erize v asc ular enc asement , duc t al obst ruc t ion and peripanc reat ic ly mph nodes remains. Art if ac t s result ing f rom more c omplex CPR t ec hniques may be enc ount ered (F ig. 15- 7).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2202

15 - The Pancreas

F igure 15- 7 Panc reat ic adenoc arc inoma of body /t ail junc t ion, loc at ed in large hiat al hernia. A: Axial image t hrough t he upper abdomen/low er c hest in panc reat ic parenc hy mal phase demonst rat es hy poat t enuat ing mass in t he body /t ail of panc reas, loc at ed w it hin a v ery large hiat al hernia. Peripanc reat ic st randing and upst ream duc t al dilat at ion are not ed. Splenic art ery is enc ased. B: Angled c oronal v olume rendered image t hrough t he upper abdomen demonst rat es t he normal appearing panc reat ic parenc hy ma in t he head, nec k, and body , w it h hy poat t enuat ing mass at t he body /t ail junc t ion, duc t al dilat ion/inf lammat ory c hanges inv olv ing t he t ail. C : Coronal c urv ed planar ref ormat t ed image aligned w it h t he inv ert ed U- shaped main panc reat ic duc t demonst rat es t erminat ion of t he upst ream dilat ed duc t (ar r ow ) in t he mass (ar r ow head) at t he t ail/body junc t ion, and normal appearing panc reat ic duc t in t he remainder of t he gland. D: Axial c urv ed planar ref ormat t ed image aligned w it h t he inv ert ed U- shaped main panc reat ic duc t demonst rat es t erminat ion of t he upst ream dilat ed duc t (ar r ow ) in t he mass (ar r ow head) at t he t ail/body junc t ion and normal appearing panc reat ic duc t in t he remainder of t he gland. Not e but t erf ly art if ac t due t o t w o c urv ed direc t ions (superiorinf erior and ant erior- post erior) in t his pat ient w it h marked panc reat ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2203

15 - The Pancreas posit ional dist ort ion due t o t he hiat al hernia. L, liv er; D, diaphragmat ic c rus; A, aort a.

One of t he main adv ant ages of 32- t o 64- slic e sc anners f or t he panc reas is t he abilit y t o perf orm a CT - perf usion st udy of t he ent ire gland rat her t han at a single anat omic lev el. In t he f ut ure, CT - perf usion inf ormat ion may be helpf ul f or det ec t ing panc reat ic adenoc arc inomas t hat are isodense t o panc reat ic parenc hy ma or f or predic t ing w hic h t umors are likely t o respond t o v arious t reat ment regimens (part ic ularly c hemot herapy ). P.1013 F or t he f ollow - up of panc reat ic masses af t er surgic al resec t ion (F ig. 15- 8), rout ine abdominal sc anning is usually adequat e. Surgic al c lips t y pic ally produc e problemat ic art if ac t s in t he surgic al bed, limit ing t he qualit y of post proc essed images. If t he pat ient has rec eiv ed radiat ion and/or c hemot herapy af t er t he init ial diagnosis of a panc reat ic mass, and post t reat ment response is t o be ev aluat ed prior t o c onsiderat ion of surgic al resec t ion, t he same prot oc ol as used f or t he init ial ev aluat ion of t he mass should be used.

F igure 15- 8 Rec urrent panc reat ic adenoc arc inoma in a 74- y ear- old w oman 8 mont hs af t er Whipple resec t ion w it h f ree margins. A: Panc reat ic parenc hy mal phase 5- mm c omput ed t omography image demonst rat es at rophied panc reat ic body and t ail (ar r ow ). T here is abnormal hy pov asc ular sof t t issue surrounding t he c eliac axis, post erior t o t he c lip. Mult iple hepat ic met ast ases are present . B: 3.5 c m inf eriorly , t here is beam hardening art if ac t due t o mult iple surgic al c lips, a c ommon f inding in pat ient s af t er Whipple. Liv er met ast ases and abnormal sof t t issue ant erior t o t he lef t renal v ein are c learly ev ident despit e t he art if ac t .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2204

15 - The Pancreas

When panc reat it is is a c linic al c onc ern, t he goals of t he CT examinat ion are t o c onf irm a suspec t ed but unc ert ain c linic al diagnosis and, more import ant ly , t o ev aluat e f or c omplic at ions of panc reat it is suc h as panc reat ic nec rosis (F ig. 15- 9), hemorrhage, inf ec t ion, dev elopment of panc reat ic P.1014 f luid c ollec t ions, or dev elopment of v asc ular c omplic at ions suc h as v enous t hrombosis or pseudoaneury sm f ormat ion. As opposed t o panc reat ic mass ev aluat ion, high- densit y oral c ont rast agent should be used t o ideally def ine relat ionships of pot ent ial f luid c ollec t ions t o adjac ent bow el and ident if y f ist ulae (99). CT A is not rout inely used f or t his indic at ion but c an be used if v asc ular c omplic at ions are suspec t ed in part ic ular (T ables 15- 3 and 15- 4).

F igure 15- 9 T w o w eeks post onset of gallst one panc reat it is w it h sev ere nec rosis. A: Comput ed t omography sc an t hrough t he lev el of t he body of t he panc reas show s enhanc ement in only a small port ion of t he t ail of t he panc reas (ar r ow s). T he skelet onized c ommon bile duc t (open ar r ow ) c ourses t hrough t his loc ulat ed c ollec t ion. B: Enhanc ement of t he panc reat ic head (ar r ow s) is preserv ed. No ot her port ions of t he panc reas, in addit ion t o t he small port ion of t he t ail, remained v asc ularized. Not e t he het erogeneous c omposit ion of t he mat erial w it hin t he dist ended ant erior pararenal spac e, ref lec t ing t he proc ess of nec rosis. Not e also t he preserv at ion of t he sleev e of f at (c ur v ed ar r ow ) surrounding t he enhanc ing superior mesent eric art ery . T his pat ient remained sev erely sy mpt omat ic f or an addit ional mont h bef ore being suc c essf ully dec ompressed by an endosc opic met hod.

F or t he f ollow - up of panc reat it is, rout ine abdominal sc anning is usually adequat e. If t he pat ient 's c reat inine has bec ome elev at ed, nonc ont rast helic al CT may be used t o f ollow - up t he size of peripanc reat ic f luid c ollec t ions (F ig.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2205

15 - The Pancreas

15- 10) or t he response of t hose f luid c ollec t ions t o perc ut aneous, surgic al, or endosc opic drainage (F ig. 15- 11). TABLE 15- 3 MDC T F OR ROUTINE ABDOMEN OR PANC REATITIS Cont rast : IV 150 mL 4/sec , Oral- 720 mL 3% iodinat ed c ont rast medium. Port al v enous phase (PVP): 60- sec delay , large F OV, diaphragm t o iliac c rest , 5 mm c ollimat ion w /5 mm rec on in HQ t able speed of 1 c m/sec (7.5 mm/0.8 sec ). Consider ac quiring: Panc reat ic parenc hy mal phase (PPP): 35- sec delay , 2.5 mm w /5 mm rec on int erv al HQ, t able speed 1 c m/sec (7.5 mm/0.8), c ov erage t hrough panc reas t o ev aluat ed nec rosis in pat ient s w it h sev ere ac ut e panc reat it is. F OV, f ield of v iew ; HQ, high qualit y ; MDCT , mult idet ec t or c omput ed t omography .

St andard magnet ic resonanc e imaging (MRI) t ec hniques f or ev aluat ion of t he panc reas mirror t hose of CT w it h respec t t o t he t iming of t he sc ans af t er IV c ont rast injec t ion of ext rac ellular f luid c ont rast agent s suc h as gadolinium c helat es. F or panc reat ic mass ev aluat ion, T 1- w eight ed f at suppressed images may be obt ained in t he axial or c oronal planes prior t o IV gadolinium enhanc ement , 35 t o 45 sec onds af t er c ommenc ement of c ont rast f or t he panc reat ic parenc hy mal phase and 70 sec onds f or t he port al v enous phase. T hese T 1- w eight ed images are generally gradient ref oc used ec ho (GRE) sequenc es w it h breat hhold t ec hnique (F ig. 15- 12) (302). Wit h t he inc reasing use of pow er injec t ors f or P.1015 gadolinium administ rat ion, t iming issues f or ideal panc reat ic and peripanc reat ic v asc ular enhanc ement are ev olv ing as in MDCT . Kanemat su et al. (161) suggest t hat t he best dual- phase met hod f or dy namic breat hhold GRE post gadolinium images t o be obt ained is t o init iat e imaging so t hat middle of t he f irst ac quisit ion oc c urs 15 sec onds af t er init iat ion of c ont rast administ rat ion at 3 mL per sec ond and t o repeat t he sequenc e at 45 sec onds (middle of ac quisit ion) f or ev aluat ion of peripanc reat ic v eins and liv er. T 2w eight ed imaging of t he panc reas is not rout inely used f or mass ev aluat ion but is used f or ev aluat ion of pot ent ial liv er met ast ases. F ast spin ec ho or single shot f ast spin ec ho t ec hniques may be used. One adv ant age of MRI is t he abilit y t o perf orm magnet ic resonanc e c holangiopanc reat ography (MRCP). When a panc reat ic mass is suspec t ed c linic ally ,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2206

15 - The Pancreas P.1016

MRCP may be t he f irst sequenc e perf ormed on a pat ient t o loc alize t he lev el of biliary or panc reat ic duc t obst ruc t ion f or t he remaining T 1 f at suppressed and post IV gadolinium enhanc ed images. New er MRI t ec hniques using manganese based IV c ont rast media t hat is t aken up by normal hepat ic and panc reat ic t issue hav e been used t o def ine f oc al panc reat ic lesions (294). TABLE 15- 4 SDC T F OR ROUTINE ABDOMEN OR PANC REATITIS Cont rast : IV—150 mL 3/sec , Oral—720 mL 3% iodinat ed c ont rast medium. Port al v enous phase (PVP): 70- sec delay , 7 mm f rom diaphragm t o c rest , if lengt h of breat hhold allow s, narrow t o 5 mm t hrough panc reas, 1:1 pit c h, larger F OV. F OV, f ield of v iew ; SDCT , single det ec t or c omput ed t omography .

F igure 15- 10 Hemorrhagic panc reat it is demonst rat ed w it h nonc ont rast c omput ed t omography (CT ) in a 38- y ear- old man w it h know n panc reat it is and elev at ed c reat inine, w orsening c linic ally . A 5- mm oral- c ont rast - only CT image demonst rat es t w o het erogeneous f luid c ollec t ions (* ), one loc at ed ant erior t o t he nec k, t he ot her post erior t o t he t ail; bot h c ont ain high- densit y ac ut e hemorrhage.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2207

15 - The Pancreas

F igure 15- 11 Inf ec t ed panc reat ic nec rosis inc omplet ely drained by perc ut aneous c at het er in a 50- y ear- old man w it h onset of ac ut e nec rot izing panc reat it is 6 w eeks earlier, t ransf erred f or f ailure t o improv e. A: A 7- mm port al v enous phase c omput ed t omography (CT ) image demonst rat es ant erior perc ut aneous c at het er ent ering a het erogeneous, gas c ont aining, mult iloc ulat ed f luid c ollec t ion in t he panc reat ic bed. Small amount of enhanc ing gland is seen w it hin t he head region at t his lev el. B: Spot radiograph during endosc opic drainage rev eals port ions of t he perc ut aneous c at het er (ar r ow ). T he endosc opic c at het er (ar r ow heads) has been plac ed f rom t he st omac h int o t he c ollec t ion, w it h injec t ion demonst rat ing mult iple large f illing def ec t s c onsist ent w it h nec rot ic debris. C : T hree mont hs lat er af t er t ransgast ric endosc opic drainage of t he c ollec t ion c ombined w it h t he perc ut aneous c at het er f or irrigat ion, CT w it h oral- c ont rast - only show s near

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2208

15 - The Pancreas c omplet e c ollapse of t he c av it y surrounding t he int rapanc reat ic port ions of t he t ransgast ric double J st ent s.

Normal Anatomy Considerable v ariat ion exist s in t he size shape and loc at ion of t he normal panc reas, depending on dif f erenc es in body habit us as w ell as t he normal or abnormal size and posit ioning of c ont iguous organs. In t he most c ommon normal c onf igurat ion, t he long axis of t he body and t ail t he panc reas lies in an oblique orient at ion, ext ending f rom t he hilum of t he spleen at it s lat eral and most c ephalad ext ent , t ow ard t he midline of t he body , w here it passes ant erior t o t hat port ion of t he port al v ein f ormed by t he c onf luenc e of t he superior mesent eric v ein and splenic v ein (F ig. 15- 13). At t his point , t he panc reas t urns c audally in a more v ert ic al orient at ion ending in t he unc inat e proc ess, it s most c audal ext ent . T he main panc reat ic duc t in most people represent s t he f usion of t he dorsal duc t (Sant orini) and t he v ent ral duc t (Wirsung) and empt ies int o t he duodenum t hrough t he major papilla. In one t hird or slight ly more of normal indiv iduals, a separat e drainage sit e f or t he c ont inuat ion of t he dorsal duc t is loc at ed in t he medial w all of t he duodenum proximal t o t he major papilla. T his is ref erred t o as t he minor papilla. Highqualit y CT and MRI c an def ine t he anat omy of t he panc reas, inc luding it s duc t sy st em w it h great prec ision, af f ording inf ormat ion on t he int egrit y of t he panc reat ic parenc hy ma, t he c aliber of t he duc t sy st em, and t he relat ionships of t he panc reas t o surrounding anat omic st ruc t ures (F ig. 15- 14). Modern CT and MRI c onsist ent ly show t hat t he t hic kness of t he normal panc reat ic parenc hy ma, measured perpendic ular t o it s long axis on t he c ross- sec t ional v iew , v aries depending on w het her t he head, nec k, body , or t ail is measured. T he t hic kness of t he head av erages approximat ely 2.0 c m; t he nec k of t he panc reas, just ant erior t o t he port al v ein, it s t hinnest port ion, ranges in t hic kness f rom 0.5 t o 1.0 c m. T he body and t ail range f rom 1.0 t o 2.0 c m, w it h many normal glands t apering slight ly t ow ards t he t ail. T he c ephaloc audal dimension of t he body and t ail ranges f rom 3.0 t o 4.0 c m in most indiv iduals, w hereas t he c ephaloc audal dimension of t he head P.1017 is more v ariable, and port ions of t he head c an be seen ov er dist anc es ranging f rom 3.0 c m t o as muc h as 8.0 c m. Wit h respec t t o size and shape, t he most reliable indic at or of a panc reat ic mass has been t he presenc e of an abrupt f oc al c hange rat her t han generalized v ariat ions f rom t he range of normal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2209

15 - The Pancreas dimensions. How ev er, w it h t he use of high- qualit y c ont rast - enhanc ed helic al CT imaging subt le f oc al c hanges in t he panc reat ic parenc hy ma indic at iv e of t he presenc e of t umor, w hic h do not c hange t he size or shape of t he panc reas, c an be def ined (196). CPRs aligned w it h t he panc reat ic duc t may also aid in t he ident if ic at ion of small, nonc ont our- alt ering adenoc arc inomas (F ig. 15- 15) and bet t er def ine t he relat ionships of int raduc t al papillary muc inous t umors (IPMT s) t o t he main panc reat ic duc t or side branc hes (242) (F ig. 15- 16). Rec ent det ailed analy ses of normal v ariat ions in t he lat eral c ont our of t he head and nec k of t he panc reas, obt ained w it h helic al CT examinat ions, hav e show n t hree general c at egories of v ariat ion f rom P.1018 t he normal f lat int erf ac e of t he lat eral border of t he head of panc reas t o t he medial w all of t he duodenum, w hic h c ould be misint erpret ed as a f oc al mass (285). In eac h inst anc e, t he c harac t er of t he enhanc ement of t he f oc al

v ariat ion w as ident ic al t o t he adjac ent normal panc reat ic parenc hy ma st udied during t he parenc hy mal phase, allow ing a c orrec t int erpret at ion. New er t ec hniques of MRI also allow f or det ec t ion of subt le lesions t hat do not alt er t he size or shape of t he panc reas.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2210

15 - The Pancreas F igure 15- 12 Normal panc reat ic magnet ic resonanc e imaging. A: Angled

c oronal 5- c m slab half - F ourier ac quisit ion single- shot t urbo spin ec ho (HAST E) magnet ic resonanc e c holangiopanc reat ography demonst rat es normal c aliber biliary and panc reat ic duc t s, as w ell as t he gallbladder. B: Int rav enous gadolinium enhanc ed port al v enous phase 5- mm T 1- w eight ed f at suppressed f ast spoiled gradient (F SPGR) breat hhold image t hrough t he panc reat ic body and t ail demonst rat es normal glandular c ont our. C : Same sequenc e t hrough t he panc reat ic head show s normal c ont our and enhanc ement pat t ern.

F igure 15- 13 Normal panc reas st udied w it h c ont rast - enhanc ed helic al c omput ed t omography . Bec ause of t he pauc it y of periv isc eral f at , t he surf ac e of t he panc reas has a smoot h rat her t han lobular appearanc e. All port ions of t he panc reas are c learly def ined in t he early art erial and c apillary phase of t his dy namic st udy . A: At t he lev el of t he panc reat ic head and unc inat e proc ess (u), t he junc t ion of t he main panc reat ic duc t and c ommon bile duc t (c ur v ed ar r ow ) is c learly def ined. T he bright ly enhanc ing superior mesent eric art ery lies direc t ly ant erior t o t he aort a and post erior t o t he junc t ion of t he nec k and body of t he panc reas. B: At t he lev el of t he nec k of t he panc reas, a normal c aliber main panc reat ic duc t (open ar r ow ) is v isible ov er sev eral c ent imet ers of it s lengt h. T he port al v ein, only part ially enhanc ed in t his early

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2211

15 - The Pancreas phase (blac k ar r ow ), lies immediat ely post erior t o t he nec k of t he panc reas

and lat eral t o t he superior mesent eric art ery . T he t issue plane separat ing t he lat eral surf ac e of t he panc reat ic head and medial w all of t he duodenum (c ur v ed ar r ow ) is w ell seen at t his lev el. Ar r ow head, Ant erior superior panc reat ic oduodenal art ery , w hic h is also v isible in F ig. 15- 2A. C : More c ephalad at t he lev el of t he body of t he panc reas, a short segment of t he main panc reat ic duc t (ar r ow head) is v isible. As t he c ont rast reac hes t he early v enous phase, t he lef t renal v ein (c ur v ed ar r ow ) is w ell opac if ied. D: At t his most c ephalad lev el t he body and t ail of t he panc reas are now seen t o be unif ormly enhanc ed and sharply def ined by t he post erior w all of t he st omac h (ar r ow s). T he hepat ic v eins (c ur v ed ar r ow s) are not y et enhanc ed at t his phase.

F igure 15- 14 Normal panc reat ic anat omy . Det ailed v iew s of c omput ed t omography (CT ) sc ans t hrough t he nec k and head of t he panc reas. A: T he main panc reat ic duc t lies in t he plane of t he CT sc an as it passes t hrough t he nec k of t he panc reas (ar r ow head). T he enhanc ing port al v ein (p) lies immediat ely post erior t o t he nec k. T he superior mesent eric art ery lies

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2212

15 - The Pancreas post erior t o t he port al v ein at t his lev el and ant erior t o t he lef t renal v ein (blac k ar r ow ). T he c aliber of t he main panc reat ic duc t at t his lev el is approximat ely 2.5 mm. A normal c aliber c ommon bile duc t (open ar r ow ) lies lat eral t o t he main panc reat ic duc t . B: At t his lev el bot h t he normal c aliber c ommon bile duc t (ar r ow ) and main panc reat ic duc t (c ur v ed ar r ow ) are seen in c ross- sec t ion as t hey approac h t he ampulla. C : 5 mm c audal, t he main panc reat ic duc t and c ommon bile duc t hav e joined t o f orm t he ampulla (ar r ow ). Not e t hat in t his pat ient , t he head of t he panc reas lies direc t ly ant erior t o t he aort a rat her t han t o t he right of it . T he superior mesent eric art ery lies post erior t o t he superior mesent eric v ein (v ). D: CT sec t ion just c audal t o t he ent ry of t he ampulla int o t he major papilla. No duc t s are v isible at t his lev el, w hic h is t hrough t he most c audal port ion of t he head of t he

panc reas and unc inat e proc ess. Not e t he gast roc olic t runk (c ur v ed ar r ow ) as it ent ers t he ant erior aspec t of t he superior mesent eric v ein.

T he surf ac e c ont our of t he panc reat ic parenc hy ma c an eit her be smoot h or lobular, t he lat t er being more f requent ly seen w hen t here is abundant peripanc reat ic ret roperit oneal f at . Alt hough t he panc reas is t ot ally inv est ed in f ine c onnec t iv e t issue, it does not hav e a t rue f ibrous c apsule. T heref ore, t he lobular arc hit ec t ure of t he panc reas is w ell def ined by t he int erdigit at ed peripanc reat ic f at (F ig. 15- 17). F at t y replac ement of muc h of t he panc reat ic subst anc e is a c ommon degenerat iv e proc ess seen in t he P.1019 elderly . How ev er, marked int erdigit at ion in t he peripanc reat ic f at c an simulat e t his lat e degenerat iv e proc ess in obese indiv iduals. F at t y replac ement may also be assoc iat ed w it h alt erat ions in panc reat ic f unc t ion and may be a lat e sequel t o v arious f orms of c hronic panc reat it is.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2213

15 - The Pancreas

F igure 15- 15 Small moderat ely dif f erent iat ed adenoc arc inoma arising f rom an IPMT of t he head region. Curv ed planar ref ormat ion demonst rat es nonc ont ouralt ering adenoc arc inoma as it obst ruc t s t he upst ream panc reat ic and dist al c ommon bile duc t s.

Part or all of t he normal main panc reat ic duc t c an be seen in nearly all pat ient s st udied, if high det ail CT t ec hnique is used. Wit h suc h highresolut ion, c ont rast - enhanc ed, t hin sec t ion t ec hnique, t he port ion of t he duc t w it hin t he head of t he panc reas, perpendic ular t o t he plane of t he slic e, is most c onspic uous (see F ig. 15- 14). Suc h t ec hnique also great ly inc reases t he c hanc es of demonst rat ing t hat port ion of t he duc t in t he body and t ail of t he panc reas, w hic h lies generally parallel t o t he plane of t he CT image (see F igs. 15- 1 and 15- 13). A t ec hnique of projec t ional CT c holangiopanc reat ography dev eloped by Rapt opoulos et al. (269) uses minimum int ensit y projec t ions of selec t ed slab t hic kness t issue v olumes t o v isualize t he panc reat ic and dist al bile duc t s. Wit h t his noninv asiv e t ec hnique, t he aut hors f ound improv ed depic t ion of t he duc t c ompared w it h helic al axial images alone, w it h good c orrelat ion t o endosc opic ret rograde c holangiopanc reat ography (ERCP). T he use of t his met hod is not w idespread.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2214

15 - The Pancreas

F igure 15- 16 Moderat ely dif f erent iat ed IPMT . Curv ed planar ref ormat ion demonst rat es dif f use main panc reat ic duc t dilat ion, w it h t he dilat ed papilla bulging int o t he duodenal lumen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2215

15 - The Pancreas F igure 15- 17 Normal f at t y inf ilt rat ion. Port al v enous phase 5- mm c omput ed t omography image t hrough t he lev el of t he splenic v ein and port al c onf luenc e show s low densit y f at int erdigit at ing t he normally enhanc ing panc reat ic parenc hy ma.

Anatomic Relationships T he splenic v ein lies on t he dorsal surf ac e of t he body and t ail of t he panc reas, c audal t o t he splenic art ery (see F igs. 15- 1A and 15- 13D). In c omparison w it h t he more t ort uous c ourse of t he splenic art ery , t he v ein runs c losely parallel t o t he longit udinal orient at ion of t he panc reas. Depending on how muc h ret roperit oneal f at is present , a t hin f at plane may separat e t he ant erior surf ac e of t he splenic v ein f rom t he post erior surf ac e of t he panc reat ic parenc hy ma. T he lef t adrenal gland lies post eromedial t o t he splenic v ein and t he panc reas at t he junc t ion of t he body and t ail. T he t ail of t he panc reas ext ends t o t he splenic hilum, ent ering t he splenorenal ligament and bec oming int raperit oneal f or a short dist anc e. Alt hough generally loc at ed ant erior t o t he splenic v ein, t he t ail of panc reas is oc c asionally imaged in t he same plane as, or ev en post erior t o, t he splenic v ein or a t ribut ary . T he body and t ail of t he panc reas normally are loc at ed ant erior or ant erolat eral t o t he lef t kidney . How ev er, in a pat ient lac king a lef t kidney (surgic ally remov ed or c ongenit ally absent ), or in a pat ient w it h an ec t opic P.1020 lef t kidney , t he body and t ail w ill be displac ed post eromedially , ly ing adjac ent t o t he spine and oc c upy ing t he empt y renal f ossa. Usually t here is an ac c ompany ing post eromedial rot at ion in t he posit ion of t he spleen. T he body of t he panc reas arc hes ant eriorly ov er t he superior mesent eric art ery , c lose t o it s origin f rom t he aort a, separat ed by dist inc t f at plane t hat enc irc les t he superior mesent eric art ery in all but t he leanest indiv iduals. T he superior mesent eric v ein runs parallel and t o t he right of t he superior mesent eric art ery and usually is larger in diamet er. At t he point w here t he superior mesent eric v ein joins t he splenic v ein t o f orm t he port al v ein, t he nec k of t he panc reas is seen t o pass immediat ely v ent ral t o t he port al v ein. Generally , t here is no int erv ening f at plane bet w een t he nec k of t he panc reas and t he port al v ein. T he presenc e of a f at plane bet w een t he lat eral surf ac e of t he superior mesent eric v ein and t he medial aspec t of t he unc inat e proc ess of t he panc reat ic head is v ariable.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2216

15 - The Pancreas T he head of t he panc reas lies medial t o t he sec ond port ion of t he duodenum, t o t he right of t he superior mesent eric v ein, and ant erior t o t he inf erior v ena c av a. Generally , a t hin, dist inc t f at plane separat es t he post erior surf ac e of t he head of t he panc reas f rom t he ant erior surf ac e of t he inf erior v ena c av a (IVC). T he unc inat e proc ess of t he panc reat ic head is a c urv ing, beaklike

inf erior and medial ext ension of t he head t hat originat es lat eral t o t he superior mesent eric v ein and c urv es post eriorly behind it , approximat ely at t he lev el of t he lef t renal v ein. Wit h t he improv ement in t ec hnique support ed by helic al CT sc anners, f iner det ails of art erial and v enous anat omy c an be def ined. T he art erial and v enous st ruc t ures t hat lie ant erior and post erior t o t he panc reat ic head c an now be ident if ied in a signif ic ant perc ent age of pat ient s. In 1992, Mori (231) f irst desc ribed t he appearanc e of t he normal gast roc olic t runk t hat c ourses ov er t he ant erior surf ac e of t he head of t he panc reas. T he gast roc olic t runk is f ormed by v eins t hat lie in t he t ransv erse mesoc olon, t he right gast roepiploic v ein, and t he ant erior panc reat ic oduodenal v ein. T he aut hors report ed being able t o ident if y a normal gast roc olic t runk (2.6 t o 4.7 mm diamet er) in approximat ely half of t he c ont rol group w it h CT sc ans obt ained using 10- mm t hic k sec t ions and in 90% of CT sc ans obt ained using 5- mm t hic k sec t ions. T hey also not ed abnormal dilat at ion of t he gast roc olic t runk in c ases in w hic h t he superior mesent eric v ein or port al v ein, dow nst ream f rom t he junc t ion of t he gast roc olic t runk and superior mesent eric v ein, w ere inv olv ed by disease result ing in st enosis, oc c lusion, or t hrombosis (231) (F ig. 15- 18). Wit h t he adv ent of ev en t hinner sec t ion helic al t ec hniques, peripanc reat ic t ribut ary v eins empt y ing int o t he port omesent eric v enous sy st em inc luding not only t he gast roc olic t runk but also t he right gast roepiploic v ein, f irst jejunal branc h, inf erior mesent eric v ein, lef t gast ric v ein, post erior superior panc reat ic oduodenal v ein, middle c olic v ein, right c olic v ein, and ant erior superior panc reat ic oduodenal v ein may be seen in normal indiv iduals. Lac k of v isualizat ion of t hese v eins or ident if ic at ion of t he inf erior peripanc reat ic v eins t hat in normal pat ient s are f requent ly t oo small in c aliber t o det ec t w it h t hin sec t ion helic al CT , may indic at e subt le inv asion of t he superior mesent eric v ein (SMV) or port al c onf luenc e in pat ient s w it h adenoc arc inoma of t he head of t he panc reas (138,231,346,368). Wit h MDCT , 3- D ref ormat ions help t o c reat e v enous maps t hat more c learly depic t inv olv ement by t umor t han axial images alone (97,137,186) (F ig. 15- 18). CT A t ec hniques f or larger v isc eral art eries are w ell est ablished. Alt hough early report s suggest ed t hat t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2217

15 - The Pancreas

smaller peripanc reat ic art eries w ere not w ell depic t ed w it h t hin sec t ion helic al CT (160,313), Chong et al. (64) w ere able t o demonst rat e adequat e art erial st udies in 87 of 100 normal pat ient s; using SDCT , all major abdominal art erial v essels w ere show n in all pat ient s in addit ion t o t he dorsal panc reat ic art ery in 94%, panc reat ic a magna in 52%, c audal panc reat ic in 39%, ant erior arc ade in 54%, and post erior arc ade in 72%. In a small perc ent age of pat ient s, t he head of t he panc reas may lie in a posit ion t hat is c omplet ely t o t he lef t of t he aort a. Alt hough t his sit uat ion may dev elop bec ause of an enlarging mass in t he liv er or peripanc reat ic area displac ing t he panc reas t o t he lef t , it has also been seen in pat ient s w it h no relev ant abdominal disease. In t hese inst anc es, despit e t he f ac t t hat t he head of t he panc reas is c omplet ely t o t he lef t of t he aort a, t he panc reas st ill bears t he normal relat ionship t o t he superior mesent eric v ein and art ery . It has been suggest ed t hat t he lef t - sided panc reas may be an ac quired posit ional v ariat ion due t o inc reasing laxit y of ret roperit oneal t issues oc c urring w it h age as w ell as t ort uosit y of t he abdominal aort a, c ausing it t o sw ing f art her t o t he right t han usual. In one st udy , all of t he pat ient s w ho had a lef t - sided panc reas and no assoc iat ed abdominal disease w ere older t han 50 y ears (87). T he normal- sized c ommon bile duc t , v ary ing in diamet er f rom 3 t o 6 mm, c an be seen in c ross- sec t ion w it hin t he head of t he panc reas, c lose t o it s lat eral and post erior surf ac e, appearing as a c irc ular or ov al near w at er densit y st ruc t ure. It s det ec t abilit y is improv ed if t he surrounding subst anc e of t he panc reat ic parenc hy ma is enhanc ed by IV c ont rast mat erial. Under opt imal imaging c ondit ions, t he v ert ic ally orient ed segment of t he main panc reat ic duc t ly ing in t he head c an be seen running parallel and medial t o t he c ommon bile duc t (see F ig. 15- 14C), ranging in diamet er f rom 1 t o 3 mm. T he ut ilit y of t hin sec t ion axial images in depic t ing isoat t enuat ing or small panc reat ic t umors obst ruc t ing t he duc t (99,265) and in det ermining t he relat ionship of t he side branc hes and main panc reat ic duc t in pat ient s w it h int raduc t al papillary muc inous t umor (IPMT ) (99,107) has been report ed. T he panc reas lies in t he ant erior pararenal spac e and is relat ed t o t he sec ond segment of t he duodenum along t he lat eral surf ac e of t he head and t o t he t hird and f ourt h segment s of t he duodenum along t he inf erior surf ac e of t he head, body , and t ail. T he st omac h lies ant erior t o t he P.1021 P.1022

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2218

15 - The Pancreas panc reas and is separat ed f rom it by t he pariet al perit oneum and t he lesser

sac , a pot ent ial int raperit oneal spac e. T he t ransv erse mesoc olon, w hic h f orms t he inf erior boundary of lesser sac , is f ormed by t he f usion of t he pariet al perit oneal leav es as t hey f use and ext end ant eriorly f rom t he v ent ral surf ac e of t he panc reas along it s ent ire lengt h. T he signif ic anc e of t his anat omic relat ionship bet w een t he t ransv erse c olon and t he panc reas v ia t he t ransv erse mesoc olon bec omes import ant in ac ut e panc reat it is bec ause t his perit oneal c ommunic at ion serv es as a pat hw ay f or t he f low of inf lammat ory exudat es assoc iat ed w it h panc reat it is.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

15 - The Pancreas

Computed Body Tomography with MRI Correlation , 4th Edition

2219

© 2017 Enter your company name

2220

15 - The Pancreas F igure 15- 18 Panc reat ic adenoc arc inoma w it h superior mesent eric v ein enc asement c learly ev ident on ref ormat t ed images. A: Axial 1.3- mm image obt ained in panc reat ic parenc hy mal phase t hrough t he superior panc reat ic

body demonst rat es hy pov asc ular mass enc asing proximal port ions of t he c eliac axis art eries, c onsist ent w it h nonresec t able panc reat ic adenoc arc inoma. B: Port al v enous phase axial image (same lev el, same t ec hnique) demonst rat es subopt imal v enous f illing w it h st ill perc ept ible narrow ing of t he port al v ein c onf luenc e (ar r ow ). C : port al v enous phase image slight ly inf erior t o B demonst rat es barely perc ept ible sliv er of t he nearly oc c luded SMV (ar r ow ). D: Port al v enous phase image more inf eriorly show s slight ly dilat ed middle c olic v ein and mult iple ant erior mesent eric c ollat erals due t o near oc c lusion of t he more superior SMV. E: Angled sagit t al v olume rendered image t hrough t he mesent eric / splenic c onf luenc e demonst rat es obst ruc t ion of t he superior aspec t of t he SMV, despit e poor c ont rast dy namic s. F : Angled c oronal v olume rendered image t hrough t he mesent eric / splenic c onf luenc e demonst rat es obst ruc t ion of t he superior aspec t of t he SMV. G: Axial maximum int ensit y projec t ion image demonst rat es art erial enc asement of t he c eliac axis by t he nonresec t able t umor.

When ret roperit oneal periv isc eral f at is abundant , t he panc reas w ill be w ell def ined. How ev er, ev en in lean pat ient s, t he panc reas c an be ac c urat ely delineat ed by t he use of ample quant it ies of w at er or high densit y oral c ont rast mat erial t o negat iv ely or posit iv ely opac if y t he lumen of c ont iguous loops of bow el, and IV c ont rast mat erial t o delineat e t he int ra- and peripanc reat ic v asc ular st ruc t ures.

Developmental Variants and Anomalies Panc reas div isum, t he most c ommon anat omic v ariant of t he human panc reas, is def ined as a c omplet ely separat e panc reat ic duc t al sy st em in a grossly undiv ided gland. It result s f rom f ailure of f usion of t he dorsal and v ent ral panc reat ic duc t s, w hic h normally oc c urs in t he sec ond mont h in ut ero. T he main port ion of t he panc reas, inc luding t he ant erior part of t he head, body , and t ail, is drained by t he dorsal panc reat ic duc t t hrough t he ac c essory papilla (F ig. 15- 19). T he post erior inf erior part of t he head and unc inat e proc ess are drained by t he short , narrow , v ent ral panc reat ic duc t t hat joins t he c ommon bile duc t in t he ampulla. In aut opsy series, panc reas div isum has an inc idenc e of 5% t o 10%. As an ERCP f inding, t he inc idenc e is up t o 4% (230,234). In a series of pat ient s w it h panc reat it is, how ev er, t here w as a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2221

15 - The Pancreas 16% inc idenc e of panc reas div isum, and t he inc idenc e of t he abnormalit y inc reased t o 25% in idiopat hic panc reat it is (68). In a large ERCP series of

1,741 pat ient s, 94 (5.5%) pat ient s w ere disc ov ered t o hav e panc reas div isum; in t hose pat ient s, panc reat it is w as f ound in 54 (57%), w it h t he majorit y of c hanges af f ec t ing t he dorsal panc reat ic duc t (230). T heref ore, it appears as t hough panc reas div isum is assoc iat ed w it h panc reat it is. T he diagnosis of panc reas div isum c an be suggest ed w it h high- det ail CT and MRI w hen an isolat ed v ent ral duc t is ident if ied or w hen separat e dorsal and v ent ral panc reat ic moiet ies c an be def ined. Wit h MRCP, panc reas div isum is rout inely imaged (F ig. 15- 20) (31,57,190). Alt hough t he ov erall size of t he panc reas may be normal in t his dev elopment al v ariant , t he c ranioc audal ext ent or ant eropost erior (AP) t hic kness of t he panc reat ic head may be inc reased. Addit ionally , t he v ent ral and dorsal moiet ies may be dist inc t ly v isible, separat ed by f at plane (373). Annular panc reas, a rare dev elopment al anomaly w it h only t hree c ases report ed among 20,000 aut opsies (149,273) may be suggest ed on CT by apparent t hic kening of t he ant erior, lat eral, and post erior aspec t of t he desc ending duodenum P.1023 c aused by t issue hav ing a densit y and enhanc ement c harac t erist ic s ident ic al t o t hat of t he panc reat ic parenc hy ma (F ig. 15- 21) (6,142,149). T he diagnosis of annular panc reas on CT w ill be reinf orc ed by t y pic al c hanges on an upper gast roint est inal (GI) radiogram and c onf irmed by suc c essf ul demonst rat ion of t he port ion of t he panc reat ic duc t sy st em w it hin t he annular c omponent by ERCP or MRCP.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2222

15 - The Pancreas

F igure 15- 19 Chronic panc reat it is due t o panc reas div isum. A: Endosc opic ret rograde c holangiopanc reat ography (ERCP) spot radiograph demonst rat ing injec t ion int o t he major papilla show s opac if ic at ion of t he v ent ral panc reat ic duc t w it h arborizing pat t ern. B: Spot radiograph f rom ERCP demonst rat ing injec t ion int o t he minor papilla show s ext ensiv e dilat at ion of t he dorsal panc reat ic duc t and side branc hes in a pat t ern c onsist ent w it h sev ere c hronic panc reat it is. A minor papilla sphinc t erot omy w as perf ormed. C : A 5- mm port al v enous phase c omput ed t omography image demonst rat es beadlike dilat at ion of t he dorsal panc reat ic duc t , c orresponding t o t he ERCP. D: 1.5 c m inf eriorly , t he st ent w it hin t he dorsal duc t is seen in c ross sec t ion, along w it h a small

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2223

15 - The Pancreas amount of ret roperit oneal gas f rom limit ed perf orat ion during t he minor papilla sphinc t erot omy . Not e t he more normal appearanc e of v ent ral panc reat ic parenc hy ma. E: Next c audal image show s pat h of minor papilla st ent int o t he duodenum, ant erior t o t he nondilat ed dist al c ommon bile duc t (ar r ow ). A dilat ed side branc h of t he dorsal duc t al sy st em (* ) is also apparent .

Agenesis of t he dorsal panc reat ic moiet y has been report ed (304). In t his dev elopment al anomaly , only t he head of t he panc reas is v isible on CT . No panc reat ic parenc hy ma c an be P.1024 ident if ied in t he expec t ed loc at ion of t he nec k, body , and t ail. In c ont rast t o panc reas div isum, dorsal panc reas agenesis is an ext remely rare anomaly . Bec ause most of t he islet c ells are loc at ed in t he t ail of t he panc reas, t he absenc e of t he body and t ail may c ont ribut e t o t he dev elopment of diabet es. Most of t he report ed c ases of c omplet e agenesis of t he dorsal panc reas w ere in pat ient s w it h diabet es mellit us (356).

F igure 15- 20 Magnet ic resonanc e c holangiopanc reat ography (MRCP) panc reas div isum. A 5- c m slab half - F ourier ac quisit ion single- shot t urbo spin ec ho (HAST E) angled c oronal image demonst rat es t he dorsal panc reat ic duc t (Sant orini) ext ending t o t he medial duodenal w all t hrough t he minor papilla, superior t o t he exit of t he dist al c ommon bile duc t t hrough t he major papilla.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2224

15 - The Pancreas

F igure 15- 21 Annular panc reas in a 52- y ear- old w oman w it h c omput ed t omography (CT ) f or renal disease. A: A 10- mm CT image obt ained af t er oral and bef ore int rav enous (IV) c ont rast demonst rat es high- densit y c ont rast w it hin t he st omac h and duodenum. Homogeneous sof t t issue enc irc ling t he right lat eral margin of t he duodenum is t he same at t enuat ion as t he panc reat ic head, w hic h lies medial t o t he duodenum. B: Same lev el af t er IV c ont rast administ rat ion, 5- mm port al v enous phase CT image, demonst rat es similar enhanc ement of t he sof t t issue surrounding t he duodenum, indic at ing annular panc reas.

Aplasia or hy poplasia of t he unc inat e proc ess may be present in pat ient s w it h int est inal nonrot at ion. In a small series, CT demonst rat ed a small or absent unc inat e proc ess in pat ient s w it h int est inal nonrot at ion; in f our of f iv e pat ient s, mesent eric inv ersion (superior mesent eric v ein loc at ed t o lef t of superior mesent eric art ery ) w as also depic t ed (143).

Pathologic Conditions Neoplasia Adenocarcinoma Canc er of t he panc reas is c urrent ly t he nint h most c ommon malignanc y but represent s t he f ourt h most c ommon c ause of c anc er- relat ed deat h (235,236,359). T he Nat ional Canc er Inst it ut e has projec t ed 31,860 new c ases and 31,270 deat hs f or 2004 (8).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2225

15 - The Pancreas In t his c ount ry , panc reat ic c anc er has a peak inc idenc e in t he sev ent h and eight h dec ades. Adenoc arc inoma ac c ount s f or bet w een 90% t o 95% of all primary panc reat ic malignant neoplasms (T able 15- 5). Wit h respec t t o risk f ac t ors, t here is ev idenc e t o indic at e an inc reased risk of panc reat ic c anc er assoc iat ed w it h diabet es and c igaret t e smoking, but t he relat ionship t o alc ohol int ake and t o c hronic panc reat it is is less c lear (50,100,113,194). T he signs and sy mpt oms of panc reat ic c anc er are v aried and nonspec if ic .

Ot her diseases may c ause f eat ures ident ic al t o t hose experienc ed by pat ient s w it h panc reat ic c anc er. Weight loss and pain are c ommon f eat ures f or pat ient s w it h panc reat ic c anc er, w het her t he t umor is loc at ed in t he head, body , or t ail. One dist inguishing sign is t he presenc e P.1025 of jaundic e. Jaundic e w ill be present in more t han 80% of pat ient s w it h a t umor in t he head, w hereas it is most unusual in pat ient s w it h body and t ail neoplasms. TABLE 15- 5 PANC REATIC TUMOR C LASSIF IC ATION I. Epit helial neoplasms A. Exoc rine t umors 1. Duc t c ell origin a. Adenoc arc inoma b. Adenoc arc inoma v ariant s 1. Muc inous adenoc arc inoma 2. Pleomorphic large c ell c arc inoma 3. Undif f erent iat ed anaplast ic c arc inoma 4. Signet ring c ell c arc inoma 5. Adenosquamous c arc inoma 6. Mixed duc t al endoc rine c arc inoma c. Mic roc y st ic adenoma d. Muc inous c y st ic t umor e. Int raduc t al papillary muc inous t umor 2. Ac inar c ell origin 3. Unc ert ain hist ogenic origin B. Endoc rine t umors 1. Insulinoma 2. Gast rinoma 3. Gluc agonoma 4. VIPoma

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2226

15 - The Pancreas 5. Somat ost at inoma 6. Poly pept idoma 7. Carc inoid t umor 8. Pheoc hromoc y t oma 9. Small c ell c arc inoma 10.Nonf unc t ioning t umor II. Nonepit helial neoplasms A. Sarc oma B. Ly mphoma C. Met ast ases Reproduc ed f rom Demos T C, Posniak HV, Harmat h C, et al. Cy st ic lesions of t he panc reas. AJR Am J Roent genol 2002;179:1375–1388, w it h permission. T he majorit y (60% t o 65%) of panc reat ic c arc inomas oc c ur in t he head,

w hereas approximat ely 20% and 10% oc c ur in t he body and t ail, respec t iv ely . Bet w een 5% and 10% af f ec t t he panc reas dif f usely (67,104). Bec ause of t he panc reat ic head's int imat e inv olv ement w it h t he c ommon bile duc t and duodenum, t umors t hat arise t here t end t o present c linic ally at an earlier st age t han t hose t hat oc c ur in t he body or t ail. Consequent ly , t umors in t he panc reat ic head t end t o be smaller at t he t ime of disc ov ery . On rare oc c asions, v ery large t umors arising in t he head may be present w it hout c ausing jaundic e. F iv e- y ear surv iv al rat es f or panc reat ic adenoc arc inoma are as low as 2% t o 3% (236). In pat ient s w it h t umors less t han 2 c m, improv ed surv iv al rat es up t o 30% at 5 y ears hav e been observ ed (234,339). T heref ore, if helic al CT t ec hniques are t o af f ec t surv iv al it is nec essary t o ac c urat ely det ec t and st age t hese smaller c anc ers (F ig. 15- 22). Bec ause panc reat ic c anc er t ends t o be disseminat ed at t he t ime of diagnosis in t he majorit y of pat ient s, t he role of CT is t o exc lude t hose pat ient s w it h dist ant met ast ases (F ig. 15- 23) or loc al inv asion (F ig. 15- 24) f rom pot ent ial unnec essary laparot omies f or surgic al resec t ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2227

15 - The Pancreas

F igure 15- 22 Resec t able moderat ely dif f erent iat ed panc reat ic adenoc arc inoma of t he panc reat ic head. Curv ed planar ref ormat t ed image show s v ery small t umor in line w it h t he duc t al st ruc t ures. Pat ient w as suc c essf ully resec t ed and is aliv e 4 y ears lat er w it h a single hepat ic met ast asis.

Most st udies c ont inue t o support t he v iew t hat CT should be t he init ial diagnost ic proc edure in any pat ient suspec t ed of hav ing a panc reat ic neoplasm. T he landmark report of t he Radiology Diagnost ic Onc ology Group (RDOG), in w hic h t he relat iv e v alues of CT v ersus MR imaging of panc reat ic adenoc arc inoma w ere c ompared, c onc luded t hat CT is rec ommended f or init ial imaging assessment . (214). Alt hough P.1026 P.1027 ult rasound (US) is w idely used as an init ial abdominal sc reening proc edure, it has not been f ound t o be as sensit iv e as CT in def ining t he ent ire c onst ellat ion of import ant f indings relat ed t o panc reat ic malignanc ies inc luding loc al nodal spread or inv olv ement of t he major art erial and v enous st ruc t ures. T he relat iv e merit s and roles of endosc opic ult rasound (EUS) and MRI relat ing t o ev aluat ion of panc reat ic pat hology also c ont inue t o ev olv e.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2228

15 - The Pancreas

F igure 15- 23 Small panc reat ic adenoc arc inoma w it h liv er met ast ases in a 60y ear- old man w it h abdominal pain. Cont rast - enhanc ed port al v enous phase image t hrough t he body of t he panc reas demonst rat es a 2.5- c m low at t enuat ion lesion expanding t he panc reas body , immediat ely adjac ent t o t he splenic v ein. Upst ream panc reat ic duc t dilat at ion is present in t he t ail. T here is no dilat at ion of t he duc t in t he nec k and head. An adjac ent 3- c m w ellc irc umsc ribed pseudoc y st is seen ant erior t o t he mass. Also not ed are t w o 1c m liv er lesions in t he right hepat ic lobe, indic at ing inoperabilit y .

F igure 15- 24 Nonresec t able panc reat ic adenoc arc inoma w it h art erial enc asement . A: Port al v enous phase 7- mm c omput ed t omography image

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2229

15 - The Pancreas demonst rat es hy pov asc ular mass ext ending superiorly f rom t he panc reat ic nec k and body , produc ing c lassic enc asement of t he c eliac axis and it s branc hes. B: At 1.5 c m inf eriorly , a c uf f of neoplast ic sof t t issue is seen also surrounding t he superior mesent eric art ery in a pat t ern t y pic al of neurov asc ular t rac king of panc reat ic adenoc arc inoma.

F igure 15- 25 Comput ed t omography (CT ) double duc t sign w it h f oc al mass in a 63- y ear- old w oman w it h jaundic e and abdominal pain. A: Panc reat ic parenc hy mal phase 3.75- mm CT image demonst rat es dilat at ion of t he main panc reat ic duc t in t he nec k, body , and t ail. Common bile duc t is also dilat ed and c ont ains a biliary st ent . B: Panc reat ic parenc hy mal phase 3.75- mm CT image t hrough t he panc reat ic head rev eals a f oc al 2.0- c m hy poat t enuat ing mass at t he point of t erminat ion of t he biliary duc t al dilat at ion, surrounding t he st ent , c onsist ent w it h a small adenoc arc inoma. C : Port al v enous phase 3.75- mm CT image t hrough t he same lev el as B rev eals diminished but persist ent c onspic uit y of t he mass, w hic h w as resec t able.

He lica l C ompute d Tomogra phy De te ction of Pa ncre a tic Ade noca rcinoma . Sinc e t he t ime of t he RDOG st udy (214), CT imaging of panc reat ic disease has c hanged dramat ic ally w it h t he adv ent of mult idet ec t or helic al t ec hnique. T he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2230

15 - The Pancreas adv ant age of MDCT t ec hnique relat es t o it s c apac it y f or t hin sec t ion v olumet ric imaging, perf ormed in a single breat hhold at a t ime of opt imal panc reat ic enhanc ement f ollow ing IV c ont rast administ rat ion (46,49). Image rec onst ruc t ion is possible w it h t he v olumet ric ally ac quired dat a, allow ing mult iplanar v iew ing (46). T his is part ic ularly helpf ul f or ev aluat ion of t he duc t al st ruc t ures (48) and v asc ulat ure. T he t w o most import ant goals w hen perf orming CT f or ev aluat ion of panc reat ic adenoc arc inoma are det ec t ion of t he t umor and assessment of resec t abilit y (46). Sensit iv it y f or lesion det ec t ion is high, ranging f rom 93% t o 100% (46,114,196,212). CT has a posit iv e predic t iv e v alue f or t umor det ec t ion of great er t han 90%. CT is exc ellent f or det ermining nonresec t abilit y , w it h a posit iv e predic t iv e v alue approac hing 100%. How ev er, it is not as ac c urat e in depic t ing resec t able t umor. T he negat iv e predic t iv e v alue is only 56% w it h uniphasic imaging and 79% w it h dual phase (212). T he CT appearanc e of panc reat ic adenoc arc inoma is v ariable. If IV c ont rast medium is not administ ered, t he at t enuat ion v alue of t umor generally is v ery similar t o t hat of normal parenc hy ma, unless ext ensiv e nec rosis or c y st ic c hange is present . Wit hout IV c ont rast , t umors may be rec ognized only w hen t hey bec ome large and alt er t he c ont our of t he gland. When IV c ont rast medium is used, most adenoc arc inomas w ill be hy poenhanc ing w it h respec t t o t he surrounding uninv olv ed panc reat ic parenc hy ma. If c ont rast dy namic s are subopt imal, adv anc ed t umors may of t en st ill be det ec t ed and diagnosed as nonresec t able (158), but t his is not nec essarily t rue f or small lesions. Wit h good c ont rast dy namic s, ev en small t umors t hat do not produc e a c ont our alt erat ion of t he gland w ill be det ec t able as a f oc al area of diminished enhanc ement . T he c onspic uit y of t he t umor depends on t he CT t ec hnique. Bec ause most panc reat ic t umors are hy pov asc ular, t hey should exhibit great est c onspic uit y w hen display ed in a maximally enhanc ed panc reas (49). How ev er, perf orming helic al CT during art erial injec t ion of c ont rast medium does not improv e det ec t ion ov er IV c ont rast t ec hniques (109). Vary ing c onc lusions of rec ent report s ref lec t t he dependenc e of t umor c onspic uit y on t ec hnique. Lu (196) f irst desc ribed t hat t he t umor t o panc reas c ont rast w as great er in t he panc reat ic parenc hy mal phase (67 В± 19 Hounsf ield unit s)

c ompared w it h a t rue art erial phase (39 В± 16 Hounsf ield unit s) due t o great er normal panc reat ic parenc hy mal and less t umor enhanc ement at t hat part ic ular c irc ulat ory t ime (F igs. 15- 3, 15- 5, and 15- 25). T his represent s an av erage of 70% improv ement in t umor t o panc reas c ont rast . Alt hough Diehl (85)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2231

15 - The Pancreas c onc luded t hat t he art erial phase produc ed improv ed t umor c onspic uit y ov er t he port al v enous phase, t he art erial phase in t hat part ic ular st udy began 36 sec onds af t er init iat ion of c ont rast and likely resembled a panc reat ic parenc hy mal phase. Imbriac o (141) f ound no dif f erenc e in t he det ec t ion and det erminat ion of resec t abilit y c omparing art erial phase t o a c audoc ranial port al v enous phase beginning w it h a 50- sec ond sc an delay . Graf (114)

show ed t hat art erial phase images w ere inf erior t o port al v enous phase images f or t umor det ec t ion. T umor t o panc reas c onspic uit y w as 31 В± 29 Hounsf ield unit s in t rue art erial phase, and 54 В± 31 Hounsf ield unit s in port al v enous phase. Alt hough t umor enhanc ement w as signif ic ant ly higher in port al v enous phase, t he dif f erenc e bet w een t umor and panc reat ic enhanc ement w as great er. Keogan (165) f ound no st at ist ic ally signif ic ant dif f erenc e in t umor at t enuat ion subjec t iv ely bet w een t rue art erial and port al v enous phase images and c onc luded t hat t he ac quisit ion of art erial phase images does not result in improv ed det ec t ion of panc reat ic malignanc ies. Using mult idet ec t or CT t ec hniques, Mc Nult y det ec t ed 27 of 28 adenoc arc inomas and f ound t hat t umor t o panc reas Hounsf ield unit dif f erenc es w ere signif ic ant ly great er w it h panc reat ic parenc hy mal phase and port al v enous phase c ompared w it h art erial phase, but t here w as no signif ic ant dif f erenc e in t umor c onspic uit y bet w een t he port al v enous phase and panc reat ic parenc hy mal phase. It is likely t hat t he panc reat ic parenc hy mal phase of prior SDCT st udies (Lu and Boland) ov erlapped w it h t he panc reat ic parenc hy mal phase and early port al v enous phase in Mc Nult y 's MDCT st udy . Dy namic gadolinium- enhanc ed MRI of t he panc reas using breat hhold T 1w eight ed f at suppressed GRE t ec hniques demonst rat es similar lesion det ec t ion rat es c ompared w it h CT (F ig. 15- 26) (139,243,306,323). Wit h c ombined t hic k slab MRCP, breat hhold IV gadolinium enhanc ed MRA, and breat hhold T 1w eight ed GRE dy namic post gadolinium imaging, Hanninen et al. (127) report ed a 95% sensit iv it y f or lesion det ec t ion, w it h an ov erall ac c urac y of 91%. In a rec ent c omparison of SDCT and MRI using phased array t orso c oil and mangof odipir t risodium (f ormerly Mn- DPDP) as t he IV c ont rast agent , t umor det ec t ion sensit iv it y in 26 c ases w as 100% f or MRI and 94% (t w o small missed c anc ers) f or CT (294). Bec ause it is t aken up by normal panc reat ic parenc hy ma, manganese- based c ont rast agent s may be bet t er t han gadolinium c helat es in delineat ing panc reat ic t umors (84,274,282,294). Dif f usionw eight ed MRI and MR spec t rosc opy of t he panc reas may prov e usef ul in

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2232

15 - The Pancreas

c anc er det ec t ion or aid in det ermining response t o nov el t herapies in pat ient s w it h panc reat ic c anc er. T he dat a pert aining t o EUS det ec t ion of panc reat ic masses and predic t ion of resec t abilit y has been v ariable. P.1028 Af t er init ial report s indic at ing v ery high ac c urac ies f or EUS T st age (93% regardless of size) and resec t abilit y (93%), and result ant c laims of supremac y ov er inc rement al and early SDCT (115), most st udies now indic at e t hat EUS is more sensit iv e t han helic al CT in det ec t ion of smaller (10 mm) are more c ommon w it h malignant lesions. (107). Larger size may also suggest malignanc y , w it h lesions great er t han 3 c m more of t en being malignant (145). Communic at ion of t he c y st ic lesion w it h t he main panc reat ic duc t may be demonst rat ed on SDCT in 70% of pat ient s (107). T he c ommunic at ion of t he mass t o t he main duc t is part ic ularly w ell depic t ed on t hin sec t ion c oronal MRCP sourc e images (251). Koit o (176) f ound t hat det ec t ion of c y st ic dilat ed branc hes w as signif ic ant ly bet t er w it h MRCP t han w it h ERCP and t hat MRCP allow ed simult aneous v isualizat ion of t he main panc reat ic duc t and c y st ic side branc h lesion. Main panc reat ic duc t IPMT produc es dif f use dilat ion of t he main panc reat ic duc t , of t en w it h at rophy of t he gland t o a t hin rim of t issue surrounding t he duc t (118) (see F ig. 15- 16). Oc c asionally , dy smorphic c alc if ic at ions may be present w it hin t he duc t (313). On CT , t hese f eat ures may mimic c hronic panc reat it is, and t his is an import ant dif f erent ial diagnosis t o c onsider,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2263

15 - The Pancreas bec ause abdominal pain and diabet es may also be present in bot h kinds of pat ient s (35) (F ig. 15- 48). In general, pat ient s w it h main duc t IPMT present at a lat er age t han pat ient s w it h c hronic panc reat it is (35). Unlike t y pic al c hronic panc reat it is pat ient s, pat ient s w it h IPMT hav e muc in dist ending t he

dist al duc t , w hic h on CT of t en result s in an enlarged, bulging papilla projec t ing int o t he duodenal lumen (313). F ormerly , ERCP w it h v isualizat ion of abundant muc in exit ing t he papilla w as c onsidered t he gold st andard f or diagnosing IPMT (192). How ev er, MRI w it h MRCP is now rec ognized as superior t o ERCP bec ause of it s abilit y t o rev eal t he f ull ext ent of duc t al inv olv ement , of t ent imes prev ent ed on ERCP w hen muc in obst ruc t s t he main panc reat ic duc t or side branc hes (176,313). In addit ion t o MRCP, st andard T 1- and T 2- w eight ed images c an be used t o look f or ev idenc e of loc al spread. Imaging f eat ures t hat suggest malignanc y inc lude a duc t diamet er great er t han 15 mm and t he presenc e of large f illing def ec t s w it hin t he dilat ed duc t (145,313). Irie et al. (145) f ound w it h MRCP t hat in pat ient s w it h main duc t t y pe t umors, great er mean duc t dilat ion (20 mm c ompared w it h 11 mm), dif f use rat her t han segment al main panc reat ic duc t expansion, and int raduc t al f illing def ec t s w ere assoc iat ed w it h malignanc y . T he absenc e of nodules does not ensure benignanc y how ev er (145). Alt hough main duc t t y pe t umors are more likely t han side branc h t y pe t o be malignant , t he presenc e and degree of inv asion c annot be reliably det ermined w it h CT or MRI (313) or on c linic al grounds. Bec ause t hey are all c onsidered premalignant , resec t ion is t he rule f or main duc t t y pe IMPT (35). A rec ent st udy of 49 pat ient s w it h IPMT using EUS and int raduc t al sonography show ed a high ac c urac y rat e in det ermining inv asiv e P.1047 IPMT f rom noninv asiv e lesions, report ing a sensit iv it y of 55%, spec if ic it y of 97%, and ac c urac y of 88% (369); how ev er, int raduc t al sonography is not w idely av ailable.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2264

15 - The Pancreas

F igure 15- 46 Side branc h int raduc t al papillary muc inous t umor (IPMT ) of unc inat e in a 52- y ear- old asy mpt omat ic w oman. Port al v enous phase 5- mm c omput ed t omography image demonst rat es a 2.0- c m, part ially sept at ed low at t enuat ion mass w it hin t he unc inat e proc ess t hat is t y pic al of small side branc h IPMT . Not e absenc e of main panc reat ic duc t dilat ion.

F igure 15- 47 Side branc h int raduc t al papillary muc inous t umor (IPMT ) in a 77- y ear- old w oman w it h abdominal pain. A: Cont rast - enhanc ed port al v enous

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2265

15 - The Pancreas

phase image t hrough t he panc reat ic body demonst rat es dilat at ion of t he main panc reat ic duc t . No int raduc t al c alc uli are ev ident . B: Port al v enous phase image t hrough t he panc reat ic head demonst rat es c onnec t ion of dilat ed side branc h c y st ic lesion t o t he main panc reat ic duc t . C : A 2.4- c m c y st ic mass in t he post erior aspec t of t he panc reat ic head is c onsist ent w it h t he side branc h t umor, prov en at surgery . Hist ologic ally , t he t umor did not ext end int o t he main duc t , w hic h w as dilat ed due t o inc reased muc in produc t ion.

Mucinous C y stic Ne opla sm. T his c y st ic panc reat ic lesion has been prev iously know n as mac roc y st ic adenoma, muc inous c y st adenoma or c y st adenoc arc inoma, and muc in hy persec ret ing c arc inoma (118). As w it h IPMT , t he muc inous c y st ic neoplasm c av it y is f illed w it h muc inous mat erial and may hav e papillary projec t ions and nodules. Unlike IPMT how ev er, no c ommunic at ion w it h t he panc reat ic duc t al sy st em should be present . Also unlike IMPT , t hese t umors are more c ommon in f emales (9:1 f emale- t o- male rat io) in t he f if t h t o sixt h dec ade and are t y pic ally loc at ed in t he body or t ail of t he panc reas. Bounded by a t hic k f ibrous c apsule, t he epit helial lining of t his t umor c ont ains a v ariable populat ion of abnormal c ells ranging f rom benign t o dy splast ic t o malignant . Alt hough t he minorit y of t hese t umors are f rankly malignant at t he t ime of diagnosis, all are c onsidered pot ent ially malignant and are resec t ed. CT demonst rat es a near w at er densit y uniloc ular or mult iloc ular c y st ic mass, usually 6 t o 10 c m in diamet er, alt hough some t umors may grow as large as 30 c m (118). T his t umor is t y pic ally loc at ed w it hin t he panc reat ic body or t ail (F ig. 15- 49). T he c y st w alls may be irregular and c ont ain nodular exc resc enc es or sept at ions t hat are best demonst rat ed af t er IV c ont rast administ rat ion (F ig. 15- 50). Alt hough t he presenc e of enhanc ing nodules and sept at ions c orrelat es w ell w it h malignanc y , t heir absenc e does not prec lude malignanc y . Curv ilinear c alc if ic at ions may be present w it hin t he peripheral c apsule or c y st w alls. In a rec ent rev iew , t he presenc e of peripheral t umoral c alc if ic at ion w as t he only st at ist ic ally signif ic ant f inding assoc iat ed w it h ident if y ing muc inous t umors c ompared w it h ot her c y st ic panc reat ic lesions (72). When mult iloc ular, indiv idual c y st s t end t o be great er t han 2 c m diamet er and f ew er t han six in number (156). Bot h MRI and US may depic t t he f eat ures of sept at ions and c y st w all exc resc enc es in t hese lesions (61,80,118,298), but t he peripheral c alc if ic at ions are easier t o see on CT t han on MRI (80).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2266

15 - The Pancreas Muc inous c y st ic neoplasm may be mist aken f or a v ariet y of benign panc reat ic lesions (72,80,264,298). Alt hough muc inous c y st ic neoplasm should be c onsidered w hen a c y st ic panc reat ic mass is disc ov ered, only 5% t o 15% of c y st ic masses are neoplast ic (357). When uniloc ular, muc inous c y st ic neoplasm may mimic an inf lammat ory panc reat ic c y st ic lesion (pseudoc y st ). T he absenc e of CT f eat ures P.1048 of peripanc reat ic inf lammat ion and lac k of c hange ov er t ime, in addit ion t o lac k of c linic al hist ory or laborat ory ev idenc e of panc reat it is, aid in dif f erent iat ing a uniloc ular lesion (F ig. 15- 51) f rom t he muc h more c ommon pseudoc y st . Dif f erent iat ing c y st ic neoplasms f rom pseudoc y st s c an almost alw ay s be ac c omplished by c linic al and radiologic means, but in doubt f ul

c ases, w hen observ at ion is c ont emplat ed, or w hen it is import ant t o det ermine preoperat iv ely t he t y pe of c y st ic neoplasm, c y st f luid analy sis is usef ul (see lat er) and c an be obt ained w it h EUS aspirat ion (94,188).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2267

15 - The Pancreas

F igure 15- 48 Sphinc t er of Oddi dy sf unc t ion w it h sof t biliary c alc uli and panc reat ic duc t dilat ion mimic king int raduc t al papillary muc inous t umor. A: Cont rast - enhanc ed port al v enous phase c omput ed t omography at t he lev el of c ommon hepat ic duc t demonst rat es high densit y , nonc alc if ied st one w it hin markedly dilat ed duc t . B: Port al v enous phase image t hrough t he body of t he panc reas demonst rat es main duc t dilat ion. No int raduc t al c alc uli are ev ident . C : Port al v enous phase image t hrough t he panc reat ic head demonst rat es a st ent w it hin t he dilat ed bile duc t , adjac ent t o v ert ic al port ion of main panc reat ic duc t . D: Port al v enous phase image t hrough t he panc reat ic head slight ly inf eriorly demonst rat es c y st ic lesion ant eriorly . E: Endosc opic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2268

15 - The Pancreas

ret rograde c holangiopanc reat ography spot radiograph show s dilat ed duc t s and c ommon duc t st ones. At surgery , no malignanc y w as f ound, and t he c y st ic lesion w as c onsist ent w it h pseudoc y st .

T he more serious problem is misdiagnosing a muc inous c y st ic t umor as a benign neoplasm, t he mic roc y st ic adenoma. Mic roc y st ic adenomas are c harac t erized by mult iple P.1049 c y st s smaller t han 2 c m diamet er, but some may c ont ain larger c y st s, making t heir dist inc t ion f rom muc inous c y st ic neoplasm dif f ic ult . In selec t ed pat ient s perc ut aneous aspirat ion biopsy or EUSF NA may be used t o ident if y muc in, w hic h is not present in pseudoc y st s or mic roc y st ic adenomas (69,370), or t o c onf irm t he presenc e of gly c ogen, f ound in mic roc y st ic adenomas. Complic at ions suc h as inadv ert ent spillage of pot ent ially malignant f luid int o t he perit oneum must be c onsidered (72). In general, ev en in experienc ed hands, CT is an insensit iv e t ool f or dif f erent iat ing t hese t umors w hen c y st s great er t han 2 c m are present (72,80,167). T his dif f ic ult y is not limit ed t o CT . In a rec ent rev iew of sonographic f eat ures c onsidered t y pic al f or mic roc y st ic adenoma, Y eh et al. (370) f ound t hat if t he diagnosis is based on US f indings alone, many malignant t umors w ill be misdiagnosed as mic roc y st ic adenomas. Morphologic c harac t erist ic s of c y st ic masses on EUS c annot dif f erent iat e bet w een benign and malignant lesions (5). Neit her MRI nor US has been suc c essf ul at dif f erent iat ing subt y pes of c y st ic panc reat ic masses (217).

F igure 15- 49 Uniloc ular muc inous c y st ic neoplasm. Panc reat ic parenc hy mal phase 5- mm c omput ed t omography image demonst rat es a 3- c m w ellc irc umsc ribed low - at t enuat ion lesion at t he panc reat ic body t ail junc t ion, c onsist ent w it h uniloc ular muc inous c y st ic neoplasm; benign hist ology w as

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2269

15 - The Pancreas not ed in t he resec t ed spec imen. Low at t enuat ion f oc i in liv er are unopac if ied hepat ic v ein branc hes.

F igure 15- 50 Muc inous c y st ic neoplasm in a 47- y ear- old w oman w it h nausea. Port al v enous phase 7- mm c omput ed t omography image demonst rat es a 7- c m low at t enuat ion mass w it hin t he panc reat ic body . T he mass c ont ains mult iple enhanc ing sept at ions, slight ly irregular w all, and mild nodularit y of t he w all and sept a. At resec t ion, hy perplasia but no malignanc y w as f ound.

F igure 15- 51 Uniloc ular muc inous c y st ic neoplasm. A: Preint rav enous c ont rast 10- mm c omput ed t omography (CT ) image demonst rat es a round, low at t enuat ion lesion expanding t he ant ero- superior panc reat ic head. B: Panc reat ic parenc hy mal phase 5- mm CT image demonst rat es a uniloc ular c y st ic mass w it h a perc ept ible, slight ly irregular w all. No peripanc reat ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2270

15 - The Pancreas st randing is seen; how ev er, t he main panc reat ic duc t is dilat ed. In t he absenc e of a hist ory of panc reat it is or prior unexplained abdominal pain, f inding is suspic ious f or muc inous c y st ic neoplasm, c onf irmed at surgery .

Microcy stic Ade noma . Mic roc y st ic adenoma, also know n as serous c y st adenoma or gly c ogen- ric h adenoma, is a benign c y st ic neoplasm of t he panc reas t hat is more c ommon in f emales (f emale- t o- male rat io 2:1), oc c urs most f requent ly in t he sev ent h dec ade, and usually is not assoc iat ed w it h sy mpt oms unless large. It is w ell doc ument ed t hat mic roc y st ic neoplasms hav e no malignant pot ent ial, and t hus t hey are resec t ed only w hen sy mpt omat ic (72,179). On CT , mic roc y st ic adenomas c an be P.1050 w at er, sof t t issue, or het erogeneous mixed densit y and are usually made up of mult iple small c y st s (147). T he c ut edge of t his t umor has been desc ribed as similar t o t he c ut surf ac e of a sponge (F ig. 15- 52). Wit hin t he mass, indiv idual c y st s are t y pic ally smaller t han 2 c m, but some lesions c ont ain c y st s t hat are larger, making dif f erent iat ion f rom muc inous c y st ic neoplasm dif f ic ult on t he basis of imaging alone (F ig. 15- 53) (72,80,118,167). Enhanc ement of t he c y st w alls is v ariable af t er IV c ont rast administ rat ion; some c y st s may be apparent only af t er IV c ont rast enhanc ement (80). A c harac t erist ic f eat ure of t his lesion, alt hough seen in t he minorit y of c ases, is a c ent ral st ellat e sc ar t hat may c ont ain c alc if ic at ion (see F ig. 15- 52). MRI show s similar f eat ures as CT , w it h generalized low signal on T 1 and high signal on T 2, sept at ions, and c ent ral sc ar. US depic t s t he c y st w alls and sept a w ell; t he mass may appear ec hogenic or solid on US w hen t he c y st s are v ery small (80,199). Mic roc y st ic adenoma is one of t he panc reat ic lesions f ound in pat ient s w it h v on HippelLindau (VHL) disease (F ig. 15- 54). Rarely , mic roc y st ic adenomas may produc e a uniloc ular mac roc y st ic appearanc e on CT and t heref ore be mist aken f or uniloc ular muc inous c y st ic t umors or pseudoc y st s. A rec ent st udy f ound t hat c ombined f eat ures of loc at ion in t he panc reat ic head, lobulat ed c ont our, absenc e of w all enhanc ement , and t hin c apsule c ould help t o dist inguish t hese lesions; w hen t w o of f our c rit eria w ere used, a spec if ic it y of 83% w as ac hiev ed, and w hen t hree of f our w ere present , spec if ic it y of 100% w as ac hiev ed (68). Bec ause t he c ells of mic roc y st ic adenomas are ric h in c y t oplasmic gly c ogen and c ont ain no muc in, perc ut aneous aspirat ion may aid in t he diagnosis of t his lesion if t he imaging appearanc e is not t y pic al (69). EUS- guided aspirat ion of suspec t ed mic roc y st ic lesions w it h larger indiv idual

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2271

15 - The Pancreas c y st s may prov ide gly c ogen- ric h epit helial c ells t o allow t he diagnosis of a benign lesion (10).

F igure 15- 52 Mic roc y st ic adenoma in a 72- y ear- old w oman w it h v ague abdominal pain. A: Pre- int rav enous c ont rast 5- mm c omput ed t omography (CT ) image demonst rat es het erogeneous lobular 13 c m mass ext ending superiorly f rom t he panc reat ic head and nec k. Not e c ent ral branc hing c alc if ic at ions. B: Panc reat ic parenc hy mal phase 5- mm CT image same lev el demonst rat es enhanc ement of t he c apsule and numerous v ery f ine sept a w it hin t he lesion. C : Panc reat ic parenc hy mal phase CT image slight ly more c ephalad rev eals at rophy of t he body and t ail (ar r ow ). Not e absenc e of biliary duc t al dilat at ion despit e large size of t umor. D: Port al v enous phase 5- mm CT image t hrough t he lesion rev eals t he bet t er opac if ic at ion of t he sept a w it h t w o c y st s measuring up t o 1 c m. T he CT appearanc e suggest s a c ut surf ac e of a nat ural sponge, in t his c lassic mic roc y st ic adenoma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2272

15 - The Pancreas

F igure 15- 53 Mic roc y st ic adenoma w it h large c y st s. A: Pre- int rav enous c ont rast 5- mm c omput ed t omography (CT ) image demonst rat es a lobular low at t enuat ion mass in t he panc reat ic nec k. B: Panc reat ic parenc hy mal phase 5mm CT image rev eals mult iloc ulat ed c y st ic mass. Indiv idual c y st s measure up t o 2.0 c m diamet er. C : Port al v enous phase 5- mm CT image show s t he mass abut t ing t he right margin of t he superior mesent eric v ein, w it hout narrow ing, and a t hin rim of normally enhanc ing panc reat ic parenc hy ma post eriorly . T he imaging appearanc e suggest s a muc inous c y st ic neoplasm, likely resec t able. Hist ologic ev aluat ion af t er resec t ion demonst rat ed mic roc y st ic adenoma w it h sev eral large c y st s.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2273

15 - The Pancreas F igure 15- 54 Von Hippel- Lindau pat ient w it h numerous panc reat ic c y st s. A: Post gadolinium port al v enous phase T 1- w eight ed f ast mult iplanar spoiled gradient rec alled ec ho (F MPSPGR) breat hhold image t hrough t he panc reas

demonst rat es near t ot al replac ement of t he panc reat ic glandular t issue by low signal c y st s (ar r ow s). Larger higher signal int ensit y c y st ic lesion is seen in t he t ail, likely represent ing a prot ein c ont aining c y st . Also not ed are t w o enhanc ing sof t t issue adrenal masses, c onsist ent w it h pheoc hromoc y t omas (P). B: F eridex- enhanc ed T 2- w eight ed magnet ic resonanc e image t hrough t he same lev el demonst rat es markedly diminished signal int ensit y w it hin t he liv er due t o t he iron c ont aining c ont rast agent . Not e v aried f luid signal w it hin t he c y st s replac ing bot h t he panc reas and t he kidney s. Onc e again, sof t t issue adrenal masses c onsist ent w it h pheoc hromoc y t omas are seen.

P.1051 P.1052

Pancreatic Neuroendocrine Tumors (Islet Cell Tumors) Panc reat ic neuroendoc rine t umors are unc ommon, hav ing a prev alenc e of less t han 10 per million populat ion (140,152,222,307). Alt hough most neuroendoc rine t umors appear sporadic ally , an inc reased prev alenc e of t hese t umors is seen in pat ient s w it h VHL sy ndrome and in t hose af f ec t ed by mult iple endoc rine neoplasia t y pe I (MEN I) (206,307). Despit e t heir rarit y , t hese t umors are import ant bec ause t hey hav e a high rat e of malignanc y , ranging f rom 60% t o 92% (89). Neuroendoc rine t umors are c lassif ied as f unc t ioning (t hose t hat sec ret e v arious hormones) or nonf unc t ioning. F unc t ioning neuroendoc rine t umors are named f or t he main hormone produc ed. T he diagnosis of f unc t ioning neuroendoc rine t umors is almost alw ay s est ablished bioc hemic ally w hen t he lesion is small and easier t o resec t (7), w hereas nonf unc t ioning neuroendoc rine t umors are t y pic ally diagnosed w hen t he lesions are large and produc e sy mpt oms bec ause of mass ef f ec t . Insulinomas and gast rinomas are t he most c ommon of t hese rare t umors, w hereas gluc agonomas, VIPomas, and somat ost at inomas are muc h rarer. GRF omas (t umors t hat sec ret e grow t h hormone releasing f ac t or) are exc eedingly rare. PPomas, w hic h sec ret e panc reat ic poly pept ide, hav e no know n sy mpt oms due t o hy persec ret ion and are muc h like nonf unc t ioning or hormonally quiesc ent panc reat ic endoc rine t umors. In surgic al st udies,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2274

15 - The Pancreas nonf unc t ioning panc reat ic endoc rine t umors are report ed t o c ompose 15% t o 20% of all panc reat ic endoc rine t umors remov ed (58). In a large surgic al pat hology series, t he nonf unc t ioning t umors ac c ount ed f or 36% of all panc reat ic endoc rine t umors (175). Alt hough c ommonly ref erred t o as islet c ell t umors, t he bulk of ev idenc e suggest s a non- islet c ell duc t t umor origin (78). T he t umors are t hought t o originat e f rom c ells t hat are part of t he dif f use neuroendoc rine c ell sy st em

(117). T hese neuroendoc rine c ells share c y t oc hemic al propert ies and, t oget her w it h pheoc hromoc y t omas, melanomas, c arc inoid t umors, and medullary c arc inoma of t he t hy roid, hav e been c alled APUDomas. APUD is an ac rony m f or amine prec ursor upt ake and dec arboxy lat ion. T his w ould ac c ount f or sev eral dif f erent hormones, not present in normal islet c ells, being present in t he v arious t umors under t his c at egory . T he benign or malignant nat ure of t hese t umors is somet imes dif f ic ult t o est ablish unless met ast at ic t umor has been doc ument ed. T o est ablish t hat one of t hese t umors is benign, long- t erm f ollow - up is required. In general, 5% t o 10% of insulinomas are report ed as malignant , w hereas in v arious series 50% t o 90% of t he ot her t umors are report ed as malignant (44,71,131,151). Nonf unc t ioning panc reat ic neuroendoc rine t umors are c linic ally silent unt il t hey c ause sy mpt oms due t o t heir size or t o met ast ases. As a c onsequenc e, t hey are usually large at t he t ime of disc ov ery (F ig. 15- 55), ranging in size f rom 3 t o 24 c m in diamet er and 30% are larger t han 10 c m (90,245). It is import ant t o dif f erent iat e bet w een nonf unc t ioning neuroendoc rine t umors of t he panc reas and duc t al adenoc arc inomas bec ause pat ient s w it h endoc rine t umors of t en respond f av orably t o surgery and spec if ic c hemot herapy and c onsequent ly hav e a bet t er prognosis t han pat ient s w it h adenoc arc inomas (152). When a nonf unc t ioning neuroendoc rine t umor is enc ount ered on CT , t hree f eat ures t hat aid in dif f erent iat ion f rom an adenoc arc inoma are t he presenc e of c alc if ic at ion, t he lac k of v asc ular enc asement , and t he absenc e of c ent ral nec rosis or c y st ic degenerat ion w hen small. When larger, c y st ic degenerat ion or nec rosis may be present (307). Rarely , bot h f unc t ioning and nonf unc t ioning islet c ell t umors may appear c omplet ely c y st ic (80,191). Approximat ely 20% of panc reat ic neuroendoc rine t umors c ont ain c alc if ic at ion, w hereas less t han 2% of adenoc arc inomas do. Not ably , c alc if ic at ion is more c ommon in malignant t han in benign islet c ell t umors (55,364). Enc asement of t he c eliac art ery or superior mesent eric art ery , w hic h is c ommonly seen in adenoc arc inomas (see F ig. 15- 55), is rarely seen in t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2275

15 - The Pancreas

neuroendoc rine t umors; how ev er, enc asement of t he superior mesent eric v ein or port al v ein has been report ed (45,90). Panc reat ic neuroendoc rine t umors, ev en w hen large, may not undergo c ent ral nec rosis or c y st ic degenerat ion bec ause of t he ric h v asc ularit y , w hic h c ont inues t o grow as t he mass grow s (335). Alt hough 60% of panc reat ic neuroendoc rine t umors oc c ur in t he body and t ail, loc at ion is not usef ul as a dif f erent iat ing f eat ure in indiv idual c ases. In summary , t he diagnosis of a nonf unc t ioning or hormonally quiesc ent neuroendoc rine t umor should be c onsidered w hen a large, nonunif ormly enhanc ing, c alc if ied panc reat ic mass w it hout c y st ic areas and w it h hy perdense areas is ident if ied on a c ont rast - enhanc ed CT examinat ion (90). T he present ing sy mpt oms of a f unc t ioning neuroendoc rine t umor depend on t he hormone sec ret ed. Insulinomas are t he most c ommon f unc t ioning neuroendoc rine t umor, w it h pat ient s present ing w it h sy mpt oms of int rac t able hy pogly c emia, low blood lev els of gluc ose, and high c irc ulat ing plasma insulin. T hese lesions are essent ially alw ay s c onf ined t o t he panc reas and are small (see F ig. 15- 2), w it h 50% measuring less t han 1.3 c m (257). Gast rinomas are t he sec ond most c ommon f unc t ioning neuroendoc rine t umor, w it h pat ient s present ing w it h pept ic ulc er disease, diarrhea, abdominal pain, and elev at ed serum gast rin lev els. T hey oc c ur most f requent ly in t he general v ic init y of t he head of panc reas, inc luding t he panc reat ic head it self , t he w all of t he duodenum and st omac h, and ly mph nodes in an area t ermed t he “ gast rinoma t riangle” (F ig. 15- 56). Ninet y perc ent of t he ext rapanc reat ic gast rinomas oc c ur in t his area bounded by t he junc t ion of t he c y st ic and c ommon hepat ic duc t superiorly , t he sec ond and t hird port ions of t he duodenum inf eriorly and t he junc t ion bet w een t he nec k and body of t he panc reas medially (233,324). Similar t o insulinomas, gast rinomas usually are small (90% are less t han 2 c m in diamet er), and bot h t umors may be mult iple (gast rinomas and insulinomas are mult iple 60% and 10% of t he t ime, respec t iv ely ) (120,121,152,262,335). VIPomas (F ig. 15- 57), gluc agonomas, and somat ost at inomas P.1053 are f requent ly larger, many being great er t han 5 c m in diamet er, due t o t he nonspec if ic it y of t heir sy mpt oms and result ant delay in diagnosis (44,151,347).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2276

15 - The Pancreas

F igure 15- 55 Nonf unc t ioning islet c ell t umor and panc reat ic adenoc arc inoma in a 92- y ear- old w oman w it h abdominal pain. A: Prec ont rast 5- mm c omput ed t omography (CT ) image t hrough t he panc reat ic t ail demonst rat es a lobular, het erogeneous lef t upper quadrant mass t hat c ont ains c oarse c alc if ic at ions. B: Panc reat ic parenc hy mal phase 5- mm CT image t hrough t he lesion demonst rat es minimal enhanc ement . C : Port al v enous phase 5 mm CT image show s enhanc ement of t he irregular peripheral w all w it h c ent ral t umor nec rosis. F indings are c onsist ent w it h a nonf unc t ioning islet c ell t umor. T he c alc if ic at ions disbursed t hroughout t he subst anc e of t he t umor are unlike

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2277

15 - The Pancreas t hose of muc inous c y st ic neoplasms w hic h, w hen present , are peripheral, and also unlike t he st ellat e c ent ral c alc if ic at ion of mic roc y st ic adenoma. D:

Panc reat ic parenc hy mal phase CT image t hrough t he head of panc reas rev eals a het erogeneously enhanc ing mass enc asing t he superior mesent eric art ery (SMA) (ar r ow ). E: Port al v enous phase 5- mm CT image same lev el demonst rat es lac k of v isualizat ion of t he superior mesent eric v ein, large middle c olic c ollat eral v ein seen ent ering t he mass (ar r ow ), and enc asement of t he SMA, c onsist ent w it h nonresec t able adenoc arc inoma. GB, gallbladder.

T he report ed sensit iv it y of CT in loc alizing f unc t ioning neuroendoc rine t umors v aries f rom 30% in early st udies (86) t o 71% t o 82% w it h dual- phase helic al t ec hniques (140,307). Bec ause of t he t y pic ally small size of insulinomas and gast rinomas, t hey seldom alt er t he c ont our of t he panc reas. Generally , neuroendoc rine t umors of t he panc reas enhanc e t o a great er degree t han normal panc reat ic parenc hy ma during art erial and c apillary phases of bolus c ont rast administ rat ion and are t y pic ally hy perat t enuat ing P.1054 in bot h t he art erial and port al v enous phases (140,172,307,343,360). Oc c asionally , t he smaller t umors are best or only seen on port al v enous phase images (140,325,343) and may mimic art erial st ruc t ures on art erial phase images w hen in a peripanc reat ic loc at ion (307). T he use of w at er as a negat iv e oral c ont rast agent w ill improv e t he c onspic uit y of t he t umors w hen loc at ed in t he duodenal w all (see F ig. 15- 56) (360).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2278

15 - The Pancreas

F igure 15- 56 Mult iple gast rinomas in a 53- y ear- old w oman. A: Art erial phase 5- mm c ont rast - enhanc ed c omput ed t omography (CT ) image t hrough t he superior panc reat ic head lev el demonst rat es bright ly enhanc ing het erogeneous 3 Г— 5 c m mass t o t he right of t he superior mesent eric v ein (v ) B: Art erial phase 5- mm CT image 2 c m inf eriorly demonst rat es a round 1 c m hy perenhanc ing lesion w it hin t he medial duodenal w all (ar r ow ). C : Next c audal image demonst rat es t w o less t han 1- c m hy perenhanc ing lesions along t he post erior aspec t of t he duodenal w all in t he t hird port ion. D: Port al v enous phase 5- mm image t hrough t he suprapanc reat ic gast rinoma demonst rat es diminished enhanc ement . E: Port al v enous phase image t hrough t he t hird port ion of t he duodenum demonst rat es diminished enhanc ement w it hin t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2279

15 - The Pancreas duodenal w all lesions as w ell. Not e benef it of w at er (low densit y ) oral

c ont rast in v isualizing t hese lesions. T he pat ient underw ent Whipple proc edure and is disease f ree 8 y ears lat er.

Bec ause US and CT are readily av ailable, t hese imaging met hods may be used init ially f or t he det ec t ion and loc alizat ion of f unc t ioning endoc rine t umors of t he panc reas. How ev er, t here is ev idenc e t o show t hat MRI is at least as P.1055 ef f ec t iv e as CT (140). In t he MRI ev aluat ion of panc reat ic neuroendoc rine t umors, T 1 f at - suppressed (T 1F S) immediat e post gadolinium spoiled GRE images and T 2 f at - suppressed (T 2F S) images may be usef ul (226,300,301). T he t umors are low in signal int ensit y on prec ont rast T 1F S images, demonst rat e homogeneous or ring enhanc ement on immediat e post gadolinium spoiled GRE and are high in signal int ensit y on T 2F S images. T he MRI f eat ures t hat dist inguish neuroendoc rine t umors f rom duc t al adenoc arc inomas inc lude high signal int ensit y on T 2F S, inc reased homogeneous enhanc ement on immediat e post gadolinium images, and hy perv asc ular liv er met ast ases. Morphologic f eat ures inc lude lac k of v asc ular enc asement and absenc e of c ent ral nec rosis in large t umors as is similarly show n on CT examinat ions. MR imaging is part ic ularly helpf ul in t he ev aluat ion of neuroendoc rine t umors of t he panc reas in pat ient s w it h VHL sy ndrome, a t umor- prone group w it h renal disease f or w hom a limit at ion of bot h ionizing radiat ion and iodinat ed c ont rast is desirable. In t his populat ion, most t umors are benign, small, loc at ed in t he panc reat ic head, and assoc iat ed w it h more pheoc hromoc y t omas and f ew er panc reat ic c y st ic lesions (mic roc y st ic adenomas) t han VHL pat ient s w it hout neuroendoc rine t umors (206).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2280

15 - The Pancreas

F igure 15- 57 VIPoma in a 67- y ear- old w oman w it h unexplained diarrhea f or 1 y ear. A: Pre- int rav enous c ont rast c omput ed t omography (CT ) image demonst rat es isoat t enuat ing expansion of t he panc reat ic t ail region. B: Early port al v enous phase 5- mm CT image demonst rat es het erogeneous hy perenhanc ing mass in t he t ail of panc reas. T he mass c ont ains sev eral large v asc ular c hannels, and appears c learly separat e f rom t he f luid f illed adjac ent jejunal loops. C : Port al v enous phase 5- mm CT image demonst rat es diminished, but persist ent , enhanc ement w it hin t he mass, w hic h now appears more isoat t enuat ing w it h t he remainder of t he panc reas.

T he lit erat ure prov ides c onf lic t ing inf ormat ion on t he relat iv e merit s of MRI, t ransabdominal US, CT , and angiography in t he ev aluat ion of neuroendoc rine t umors. One st udy demonst rat ed t hat MRI w as more sensit iv e t han t he ot her imaging met hods f or det ec t ing met ast at ic disease t o t he liv er (F ig. 15- 58), but t he role of MRI remains unc lear f or det ec t ing primary panc reat ic endoc rine t umors w it h t he same st udy c it ed prev iously demonst rat ing t hat it has a low sensit iv it y (22%), equal t o t hat of US and CT , and less t han t hat of angiography (259). Anot her st udy report ed t hat MRI w it h gadolinium

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2281

15 - The Pancreas

enhanc ement and f at suppression t ec hniques demonst rat ed 91% of all primary panc reat ic P.1056 neuroendoc rine t umors (301). T he st riking dif f erenc e in sensit iv it y in t hese t w o st udies largely ref lec t s dif f erenc es in MR t ec hnique; how ev er, it may also ref lec t t he size of t he primary t umors. In t he lat t er st udy , 90% of t he t umors w ere at least 2 c m in diamet er. It appears t hat t he abilit y of t he v arious imaging met hods t o det ec t panc reat ic neuroendoc rine t umors depends on t he size of t he t umor. Using any of t he abov e st andard imaging met hods, less t han 10% of t umors smaller t han 1 c m, 30% t o 40% of t umors 1 t o 3 c m, and 70% t o 80% of t umors larger t han 3 c m w ere det ec t ed (16,17,106,152,207,259). Rec ommended imaging algorit hms f or ev aluat ion of pat ient s w it h f unc t ioning neuroendoc rine t umors are c ont rov ersial bec ause of t he v ariet y of modalit ies av ailable. In addit ion t o CT , MRI, and US, ot her t ec hniques suc h as somat ost at in rec ept or sc int igraphy , angiography , and art erial st imulat ion w it h v enous hormone sampling hav e been used in t hese pat ient s, eac h w it h unique adv ant ages and limit at ions (96).

F igure 15- 58 Gast rinoma liv er met ast ases. T 2F S A: and immediat ely post gadolinium spoiled gradient ec ho (SGE) B: images demonst rat e w elldef ined small met ast ases t hat are high in signal on T 2F S (A) and possess dist inc t ring enhanc ement immediat ely f ollow ing c ont rast (B). (Reproduc ed f rom Semelka RC, Cumming MJ, Shoenut JP, et al. Islet c ell t umors: c omparison of dy namic c ont rast - enhanc ed CT and MR imaging w it h dy namic gadolinium enhanc ement and f at suppression. Radiology 1993;186: 799–802, w it h permission.)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2282

15 - The Pancreas

Bef ore t he av ailabilit y of EUS, selec t iv e port al v enous sampling f or loc alizat ion of hormone gradient s and int raoperat iv e US w ere t he t ec hniques hav ing t he great est sensit iv it y f or det ec t ion of f unc t ioning neuroendoc rine t umors, w it h det ec t ion rat es superior t o st andard imaging met hods (244,246). Now aday s, EUS is a highly ac c urat e t ec hnique f or v isualizat ion of small f unc t ioning neuroendoc rine t umors (see F ig. 15- 2) not ev ident on CT and f or ident if ic at ion of pat ient s w it h mult iple lesions. In a series of 82 pat ient s w it h mean t umor size of 1.5 c m (71% of t umors ≤2 c m), EUS demonst rat ed a sensit iv it y of 93% and spec if ic it y of 95% (11) but w as not reliable in det ec t ing ext rapanc reat ic disease. In a populat ion of 10 pat ient s w it h suspec t ed f unc t ioning neuroendoc rine t umors, EUS ident if ied 14 t umors (mean size 1.2 c m) in 10 pat ient s; CT did not demonst rat e t he t umor or missed at least one of mult iple lesions in 9 of 10 pat ient s (112). EUSF NA may readily prov ide c y t ologic c onf irmat ion of t he lesions (112,153). Anot her EUS st udy designed as a ret rospec t iv e rev iew of 12 pat ient s w it h surgic ally prov en insulinomas report ed an 83% sensit iv it y f or EUS det ec t ion and 16% sensit iv it y f or helic al CT (15). T hese v ery low sensit iv it ies w ere f ound using v aried CT t ec hniques. A rec ent st udy of mult iphase helic al CT in 30 pat ient s w it h prov en insulinomas report ed an ov erall sensit iv it y of 83%. Most t umors w ere hy perdense on at least one phase, usually t he panc reat ic parenc hy mal phase, and f alse negat iv es w ere most c ommonly due t o t umor loc at ion adjac ent t o v essels, pedunc ulat ed morphology , or nonhy perat t enuat ing lesions (95). Insulinomas are perhaps t he most dif f ic ult neuroendoc rine t umor t o image bec ause of t heir not oriously small size. Nonet heless, bec ause of t he w ide av ailabilit y of highqualit y CT c ompared w it h EUS, it appears t hat dual- phase helic al CT w ill remain t he mainst ay of imaging in t hese pat ient s init ially , w it h EUS reserv ed f or pat ient s c linic ally suspec t ed of hav ing a f unc t ioning neuroendoc rine t umor not det ec t ed on CT .

Other Neoplastic Lesions T he solid pseudopapillary t umor of t he panc reas (f ormerly ref erred t o as solid and papillary epit helial neoplasm, papillary c y st ic neoplasm, solid c y st ic papillary t umor, et c .) is an unc ommon low - grade malignant t umor t hat oc c urs c hief ly in y oung w omen (mean age 25 y ears) (60,62). T hese t umors are generally large, w it h a mean t ransv erse diamet er of 9 c m and, alt hough predominat ing in t he t ail, c an be f ound in any port ion of panc reas (F ig. 1559). CT and MRI of solid pseudopapillary t umors w ill c ommonly show

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2283

15 - The Pancreas

hemorrhage w it h t y pic al f luid–debris lev el indic at ing blood produc t s in areas of c y st ic degenerat ion and nec rosis. In a rev iew of six pat ient s w it h t hese t umors st udied w it h P.1057 MRI, t he aut hors f ound t hat all t umors w ere w ell- demarc at ed lesions c ont aining c ent ral high signal int ensit y on T 1- w eight ed images c onsist ent w it h hemorrhagic nec rosis (250). In a more rec ent st udy , 5 of 19 pat ient s w it h prov en solid pseudopapillary t umors did not hav e high T 1 signal w it hin t he lesion and t hus c onc luded t hat t he absenc e of t his f inding should not exc lude t he diagnosis (62). T he same aut hors report ed early peripheral enhanc ement w it h progressiv e f ill in of t he mass on gadolinium- enhanc ed dy namic images, w hic h may aid in dif f erent iat ing t his t umor f rom c y st ic neoplasms and neuroendoc rine t umors of t he panc reas (62), diagnoses w it h w hic h it has been prev iously c ompared (27,60,105,173,288).

F igure 15- 59 Solid pseudopapillary t umor in a 27- y ear- old w oman undergoing ev aluat ion as pot ent ial renal donor. A: Pre- int rav enous c ont rast 3.8- mm c omput ed t omography (CT ) image t hrough t he superior panc reat ic head region demonst rat es a het erogeneous 7 Г— 9 c m mass ext ending ant eriorly f rom t he nec k. T here are f oc al c alc if ic at ions along t he periphery and w it hin t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2284

15 - The Pancreas subst anc e of t he mass. B: Panc reat ic parenc hy mal phase 2.5- mm CT image t hrough t he same lev el demonst rat es het erogeneous enhanc ement w it hin t he lesion. C : Port al v enous phase 3.8- mm CT image t hrough t he same lev el

demonst rat es progressiv e enhanc ement f rom t he periphery of t he mass. T here is displac ement of t he v asc ular st ruc t ures post eriorly . T he lesion w as resec t able.

Pleomorphic c arc inoma is an unc ommon malignant neoplasm t hat has a f ulminant c linic al c ourse. It met ast asizes early t o t he liv er, lung, adrenal, kidney , t hy roid, and bone. T his t umor show s irregular enhanc ement af t er IV c ont rast administ rat ion and may be c y st ic , w it h t hic k irregular w alls and a lobulat ed c ont our. T he presenc e of ext ensiv e ret roperit oneal ly mphadenopat hy helps t o dif f erent iat e f rom adenoc arc inoma (365). Ac inar c ell c arc inoma is a rare exoc rine panc reat ic t umor, making up only 1% of exoc rine panc reat ic t umors despit e t he f ac t t hat t he majorit y of panc reat ic parenc hy ma is made up of ac inar c ells. T hese t umors are less aggressiv e t han t y pic al panc reat ic adenoc arc inoma. On c ont rast - enhanc ed CT ac inar c ell c arc inomas may be loc at ed any w here in t he panc reas and t end t o be w ell marginat ed, exophy t ic , hy poenhanc ing, and large (333). A v ariet y of ot her rare neoplasms of t he panc reas hav e been report ed inc luding malignant giant c ell t umor, sarc oma, plasmac y t oma, lipoma, onc oc y t oma, and small c ell c arc inoma (82,83,228,248,299,358). Panc reat ic t umors are rare in inf ant s and c hildren. T he CT , MRI, and US imaging c harac t erist ic s of panc reat oblast omas, a rare panc reat ic t umor of ac inar c ell origin in c hildren bet w een ages of 1 and 8, hav e been report ed (150,198,326). Alt hough ly mphoma (F ig. 15- 60) c an inv olv e panc reas and peripanc reat ic ly mph nodes and c an be c onf used w it h a primary panc reat ic neoplasm, usually it is a sy st emic disease w it h ret roperit oneal and mesent eric ly mphadenopat hy P.1058 also present (261,309,350). On MRI, int ermediat e signal int ensit y peripanc reat ic ly mph nodes are readily dist inguished f rom high signal int ensit y panc reat ic parenc hy ma on t he T 1 f at suppressed images. Inv asion of t he panc reas is show n by loss of t he usual signal int ensit y of t he panc reat ic parenc hy ma on t he T 1 f at - suppressed images. When primary panc reat ic ly mphoma is present , t he mass is of t en larger t han a t y pic al adenoc arc inoma. In one st udy , it w as report ed t hat no adenoc arc inoma w as larger t han 10 c m, and 60% w ere bet w een 4 and 6 c m (334). Bec ause ly mphoma does not require

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2285

15 - The Pancreas surgic al st aging or palliat iv e Whipple proc edure bef ore c hemot herapy or

radiat ion t herapy , dif f erent iat ing panc reat ic ly mphoma f rom adenoc arc inoma is import ant . T w o f indings t hat may help are t he absenc e of panc reat ic duc t al dilat at ion despit e large mass size, and t he presenc e of ret roperit oneal adenopat hy loc at ed below t he lev el of t he lef t renal v ein (218). Rarer t umors suc h as malignant f ibrous hist ioc y t oma (F ig. 15- 61) may also arise in t he panc reas; t y pic ally , t he diagnosis is made w it h ev aluat ion of t he surgic al spec imen.

F igure 15- 60 Panc reat ic inv olv ement by sy st emic ly mphoma in a 36- y ear- old w oman w it h abdominal pain. A: Port al v enous phase 7- mm c omput ed t omography (CT ) image t hrough t he panc reat ic body and t ail demonst rat es het erogeneously enhanc ing expansion of t his region. Not e obst ruc t ion of lef t renal c ollec t ing sy st em. B: Delay ed 5- mm CT image t hrough t he pelv is demonst rat es bulky ly mphadenopat hy f illing t he deep pelv is. At pat hology , high grade B- c ell ly mphoma w it h some f eat ures of Burkit t 's w as f ound.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2286

15 - The Pancreas

F igure 15- 61 Panc reat ic malignant f ibrous hist ioc y t oma (MF H). A: Preint rav enous c ont rast c omput ed t omography (CT ) image demonst rat es a w ell c irc umsc ribed smoot h low at t enuat ion mass ext ending ant eriorly f rom t he body . B: Panc reat ic parenc hy mal phase CT image same lev el show s c y st ic and hy pov asc ular solid c omponent s of t he lesion. Not e f oc al int rapanc reat ic low at t enuat ion t umor and normal enhanc ement of remainder of panc reas. C : T 2 f at suppressed magnet ic resonanc e (MR) image demonst rat es f luid signal w it hin t he c y st ic c omponent . D: T 1 f at suppressed MR image rev eals high signal int ensit y w it hin t he c y st ic c omponent , indic at ing prot einac eous or hemorrhagic mat erial. Not e normal high signal w it hin t he normal panc reat ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2287

15 - The Pancreas parenc hy ma, and f oc al low signal in t he body indic at ing t he int rapanc reat ic t umor. E: T 1 f at - suppressed gadolinium- enhanc ed MR image show s hy perenhanc ement of t he solid c omponent of t he t umor, more so t han on CT . F : Surgic al spec imen c ut open t o rev eal hemorrhagic c y st ic and y ellow - t an solid port ions of t umor, c omplet ely resec t ed w it h ext ended dist al panc reat ec t omy and splenec t omy . (Surgic al phot ograph c ourt esy of Mart in J. Heslin, MD.)

Panc reat ic met ast ases, w hic h are rarely diagnosed c linic ally , most c ommonly arise f rom melanoma and c arc inomas of t he breast (F ig. 15- 62), lung, kidney , prost at e, and GI t rac t (F ig. 15- 63). Isolat ed met ast ases t o t he panc reas f rom P.1059 P.1060 primary bone t umors hav e also been report ed (286). When mult iple masses are present in t he panc reas in a pat ient w it h a know n primary c arc inoma, met ast ases c an be presumed; how ev er, w hen solit ary , it may be indist inguishable f rom primary panc reat ic c arc inoma (287). On CT , t he pat t ern of a single, loc alized mass is t he most c ommon present at ion of panc reat ic met ast asis (293). T he int erv al f rom diagnosis of an ext rapanc reat ic primary t umor t o subsequent det ec t ion of a panc reat ic met ast asis is v ariable, usually ranging f rom 1 t o 3 y ears (293), but in t he c ase of renal c arc inomas met ast ases may oc c ur many y ears af t er primary t umor diagnosis. Ident if y ing renal c arc inoma met ast ases t o t he panc reas, best det ec t ed during t he early phases of helic al CT , is pot ent ially import ant bec ause aggressiv e surgic al resec t ion may be benef ic ial (240). MRI may be usef ul in t he ev aluat ion of panc reat ic met ast ases by show ing f eat ures suc h as inc reased v asc ularit y in t he c ont ext of a hy perv asc ular primary malignanc y (164). T he majorit y of met ast ases are low signal on a bac kground of high- signal panc reas on T 1 f at suppressed images. Melanoma has a t y pic ally high signal int ensit y on T 1w eight ed images due t o t he paramagnet ic propert ies of melanin.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2288

15 - The Pancreas F igure 15- 62 Panc reat ic met ast ases f rom breast c arc inoma. A: Early port al

v enous phase 5- mm c omput ed t omography image demonst rat es a f oc al, round, 1- c m het erogeneously enhanc ing mass in t he panc reat ic nec k. Similar enhanc ement c an be seen w it hin a mass loc at ed in t he right hepat ic lobe. Mult iple lung nodules are also present on B, 5- mm image t hrough inf erior c hest f ilmed at lung w indow s. F indings are c onsist ent w it h met ast ases in t his pat ient w it h know n primary breast c anc er.

F igure 15- 63 Colon c arc inoma w it h c ont iguous spread int o t he panc reat ic head in a 77- y ear- old man w it h abdominal pain. Port al v enous phase 5- mm c omput ed t omography image demonst rat es het erogeneous, lobular sof t t issue mass replac ing t he panc reat ic head and nec k, in direc t c ont ac t w it h a similar appearing mass of t he proximal t ransv erse c olon (ar r ow ). Calc if ic at ion is seen w it hin t he subst anc e of t he mass, prov en t o be muc inous c olon c arc inoma w it h c ont iguous spread t hrough t he t ransv erse mesoc olon t o inv olv e t he panc reat ic head.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2289

15 - The Pancreas

F igure 15- 64 Ampullary mass in a 70- y ear- old w oman w it h 2- w eek hist ory of painless jaundic e. A: Panc reat ic parenc hy mal phase c omput ed t omography (CT ) image t hrough t he superior panc reas demonst rat es marked c ommon bile duc t al dilat at ion, w it h biliary endoprost hesis in plac e (ar r ow ). B: 2 c m inf eriorly , a f oc al 2- c m hy poat t enuat ing mass is seen bet w een t he dilat ed bile duc t and medial duodenal w all. C : Next c audal CT image show s het erogeneous hy poat t enuat ing mass surrounding t he dist al c ommon bile duc t at t he ampulla. D: Same lev el port al v enous phase image demonst rat es dec reased demarc at ion of t he mass c ompared t o t he normal sleev e of panc reat ic t issue seen medially on t he panc reat ic parenc hy mal phase images. At Whipple resec t ion, a 3.0- c m v illous adenoma w it h high grade dy splasia w as f ound at t he ampulla.

Periampullary t umors arise w it hin 2 c m of t he major papilla, and bec ause of t heir similar c linic al f eat ures and loc at ion may be dif f ic ult t o dif f erent iat e f rom panc reat ic adenoc arc inomas. Alt hough of t en t reat ed w it h Whipple resec t ion, t he long- t erm out c omes f or t his div erse group of t umors are generally more f av orable due t o inherent dif f erenc es in t umor biology . Ampullary v illous adenomas (F ig. 15- 64) and ampullary adenoc arc inomas (F ig. 15- 65) may c ause

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2290

15 - The Pancreas

isolat ed biliary or c ombined biliary and panc reat ic duc t dilat ion and f requent ly produc e a mass bulging int o t he duodenal lumen. Duodenal adenoc arc inomas less f requent ly result in duc t al dilat at ion and may be poly poid, P.1061 P.1062 ulc erat ing, or annular lesions t hat on CT arise t o t he right of t he dist al c ommon bile duc t . Dist al bile duc t adenoc arc inomas produc e oblit erat ion of t he duc t lumen and w hen adv anc ed inv ade t he adjac ent panc reat ic parenc hy ma; t hese may be most dif f ic ult t o dist inguish f rom panc reat ic adenoc arc inomas w it h imaging. Oc c asionally , c hronic inf lammat ion (F ig. 15- 66), squamous c arc inomas (F ig. 15- 67), or rare lesions suc h as duodenal gast roint est inal st romal t umor (GIST ) (F ig. 15- 68) may be present in a periampullary loc at ion. MRCP and sec t ional MRI may be usef ul in det ermining t he origins of periampullary lesions (169).

F igure 15- 65 Ampullary mass v ersus st one disease in an 81- y ear old w oman w it h jaundic e. A: Panc reat ic parenc hy mal phase 3.8- mm c omput ed t omography (CT ) image demonst rat es marked dilat at ion of t he bile duc t and moderat e dilat at ion of t he main panc reat ic duc t . B: Panc reat ic parenc hy mal phase 3.8mm CT image t hrough t he inf erior panc reat ic head demonst rat es a w ellc irc umsc ribed, 1.0- c m diamet er c y st ic st ruc t ure bulging t he medial duodenal w all. Dist al c ommon bile duc t lies t o t he lef t (ar r ow ). C : 1.5 c m inf eriorly , a het erogeneously enhanc ing sof t t issue mass is seen at t he abrupt t erminat ion of t he dilat ed bile duc t . At surgery , a 0.8 Г— 0.8 Г— 0.5 c m adenoc arc inoma of t he ampulla w as f ound. T he c y st ic lesion w as a small pseudoc y st .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2291

15 - The Pancreas

F igure 15- 66 Ampullary mass. A: Panc reat ic parenc hy mal phase 5- mm c omput ed t omography (CT ) image t hrough t he port a demonst rat es air w it hin t he biliary t ree in t his pat ient w it h rec ent biliary st ent plac ement . Not e dilat at ion of t he main panc reat ic duc t in t he nec k and body . B: Next c audal 5- mm panc reat ic parenc hy mal phase CT image demonst rat es empt y ing of t he duc t of Sant orini t o t he medial duodenal w all (ar r ow ) w it h biliary endoprost hesis seen w it hin t he nondilat ed dist al c ommon bile duc t . C : 1.5 c m inf eriorly , t here is a het erogeneously enhanc ing hy poat t enuat ing mass surrounding t he dist al c ommon bile duc t st ent , and ext ending int o t he duodenal lumen. D: Port al v enous phase CT image, same lev el as C demonst rat es poor demarc at ion bet w een t he mass and remaining normal panc reas. Spec imen f rom Whipple resec t ion show ed c hronic inf lammat ion and no neoplasm.

Inflammatory Diseases Acute Pancreatitis Ac ut e panc reat it is is most c ommonly assoc iat ed w it h c holedoc holit hiasis and et hanol abuse, w it h ot her et iologic f ac t ors suc h as met abolic disorders (hy perc alc emia and hy perlipidemia), t rauma inc luding ERCP- induc ed panc reat it is (F ig. 15- 69), medic at ions (azat hioprine, sulf onamides), and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2292

15 - The Pancreas st ruc t ural abnormalit ies suc h as panc reas div isum and t umors (70,193) (F ig.

15- 70) being muc h less c ommon. Most pat ient s present w it h nausea, v omit ing, and abdominal P.1063 P.1064 P.1065 pain; oc c asionally , t he sy mpt oms are indirec t ly relat ed t o panc reat ic inf lammat ion (F ig. 15- 71). Onc e t he diagnosis of ac ut e panc reat it is is est ablished, t he t reat ment of pat ient s is based on t he early assessment of disease sev erit y . Sev ent y perc ent t o 80% of pat ient s w it h ac ut e panc reat it is hav e mild disease (F ig. 15- 72), and 20% t o 30% hav e sev ere at t ac ks. Early assessment is c rit ic al f or predic t ing w hic h pat ient s are likely t o suf f er let hal at t ac ks, w hic h oc c ur in 2% t o 10% of c ases (4,21,28,30,38,39,51,81,204). T he inc reased f requenc y of deat h in ac ut e panc reat it is is direc t ly c orrelat ed w it h t he dev elopment and ext ent of panc reat ic nec rosis (F ig. 15- 73) (4,21,28,30,38,39,51,81,204). In addit ion t o c linic ally based numeric disease sev erit y grading sy st ems suc h as t he Ranson sc ore (267) and Ac ut e Phy siology and Chronic Healt h Ev aluat ion (APACHE) II assessment (182), bot h of w hic h are indic at ors of generalized sy st emic disease, IV c ont rast - enhanc ed CT is essent ial in t he ev aluat ion of pat ient s w it h sev ere ac ut e panc reat it is, bec ause it is used t o ev aluat e loc al panc reat ic morphology , most import ant ly t o ident if y and quant it at e panc reat ic glandular nec rosis (21). Alt hough v arious laborat ory assay s of enzy mes and prot eins released during episodes of sev ere ac ut e panc reat it is hav e been st udied c linic ally , inc luding serum t ry psinogen, urinary t ry psinogen- ac t iv at ed pept ide, met hemalbumin, c y t okines Il- 6 and phospholipase A2, C reac t iv e prot ein and poly morphonuc lear c ell elast ase, direc t c orrelat ion of t hese c hemic als w it h t he presenc e and ext ent of panc reat ic nec rosis, and t hus t heir c linic al ut ilit y , hav e y et t o be prov en (21).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2293

15 - The Pancreas F igure 15- 67 Squamous c arc inoma of panc reat ic head in a 52- y ear- old man

w it h 2- w eek hist ory of painless jaundic e. A: Panc reat ic parenc hy mal phase 3mm c omput ed t omography (CT ) image t hrough t he panc reat ic head demonst rat es c ommon bile duc t st ent in plac e t hrough a nondilat ed duc t . T here is hy poat t enuat ing sof t t issue loc at ed t o t he right , but not surrounding, t he dist al c ommon bile duc t as w ell as narrow ing of t he duodenal lumen. Not e gast roduodenal art ery c oursing t hrough lesion. B: Port al v enous phase 3- mm CT image same lev el demonst rat es isoat t enuat ion of t he sof t t issue mass c ompared t o t he normal panc reat ic head parenc hy ma. Af t er Whipple resec t ion, pat hologic and hist ologic ev aluat ion rev ealed t hat t he majorit y of t he squamous c arc inoma w as w it hin t he panc reat ic parenc hy ma, w it h islands of t umor ext ending int o but not t hrough t he int ac t c olumnar lining of t he bile duc t .

F igure 15- 68 Ampullary mass. A: Pre- int rav enous c ont rast 5- mm c omput ed t omography (CT ) image t hrough t he inf erior panc reat ic head demonst rat es moderat e lobularit y and relat iv e expansion of t he head c ompared t o t he remainder of t he gland. B: Panc reat ic parenc hy mal phase 2.5- mm CT image t hrough t he same lev el demonst rat es a hy perenhanc ing het erogeneous 2.3- c m mass. C : Port al v enous phase 5- mm CT image t hrough t he same lev el

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2294

15 - The Pancreas

demonst rat es diminished but persist ent ly het erogeneous enhanc ement t hrough t he same region. At surgery , a gast roint est inal st romal t umor (GIST ) of t he medial duodenal w all w as f ound.

F igure 15- 69 Endosc opic ret rograde c holangiopanc reat ography (ERCP) perf orat ion w it h panc reat it is in a 61- y ear- old w oman. A: Abdominal radiograph demonst rat es ret roperit oneal mot t led air in t he right abdomen. Gaseous dist ent ion of t he bow el is due t o rec ent endosc opic proc edure. B: Cont rast enhanc ed c omput ed t omography of t he abdomen 2 day s lat er demonst rat es persist ent ret roperit oneal air ant erior t o t he right kidney w it h a moderat e amount of ret roperit oneal f luid. Panc reat it is assoc iat ed w it h ERCP perf orat ion result ed in prolonged rec ov ery in t his pat ient .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2295

15 - The Pancreas

F igure 15- 70 Subac ut e nec rot izing panc reat it is, init ial episode in an 82- y earold man. A: Port al v enous phase 5- mm c omput ed t omography (CT ) image demonst rat es a het erogeneous, gas c ont aining c ollec t ion replac ing port ions of t he head and nec k. A t ranspapillary endoprost hesis is in plac e w it hout adequat e drainage of t he c ollec t ion. B: Endosc opic t ransduodenal naso-

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2296

15 - The Pancreas panc reat ic irrigat ion c at het er and double J st ent w ere plac ed. C : Approximat ely 5 w eeks lat er, CT demonst rat es c omplet e c ollapse of t he nec rot ic c ollec t ion. D: T w o y ears lat er, port al v enous phase 5- mm CT image t hrough t he superior panc reat ic head region rev eals f oc al def ec t produc ed by

nec rot izing panc reat it is. Upst ream main panc reat ic duc t dilat at ion and at rophy are present . E: 3 c m c audally , t here is a lobular, het erogeneously enhanc ing mass w it hin t he unc inat e, w hic h represent s biopsy prov en nonf unc t ioning neuroendoc rine t umor. In ret rospec t , t he lesion c ould not be seen 2 y ears earlier during t he episode of ac ut e nec rot izing panc reat it is, but t umors should alw ay s be sought in elderly pat ient s present ing w it h a f irst episode of ac ut e panc reat it is.

F igure 15- 71 Sc rot al inf lammat ion as t he present ing sign of ac ut e panc reat it is in a 35- y ear- old man admit t ed t o urology serv ic e f or abdominal pain and sw ollen sc rot um. A: T ransv erse sonographic image t hrough t he superior sc rot um demonst rat es a large amount of het erogeneous, part ially

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2297

15 - The Pancreas sept at ed f luid surrounding t he right t est ic le; f indings led t o c omput ed

t omography (CT ) ev aluat ion. B: Cont rast - enhanc ed port al v enous phase 5- mm CT image t hrough t he panc reas demonst rat es a moderat e amount of ret roperit oneal f luid, w hic h appears part ially organized. C : Slight ly more inf erior port al v enous phase 5- mm CT image demonst rat es f luid t rac king int o t he mesent eric root and lef t ant erior pararenal spac e. D: T ransv erse 5- mm CT image t hrough t he groin demonst rat es het erogeneous f luid surrounding t he right t est ic le. F indings are c onsist ent w it h ac ut e panc reat it is, Grade E, no glandular nec rosis, CT sev erit y index (CT SI) of 6, w it h dissec t ion of f luid int o t he sc rot um.

P.1066

Mild Acute Pancreatitis Most pat ient s w it h ac ut e panc reat it is hav e c linic ally mild disease, also c alled int erst it ial or edemat ous panc reat it is. T his is a self - limit ed disease w it h unev ent f ul rec ov ery , minimal organ dy sf unc t ion, and no signif ic ant c omplic at ions. If ac ut e panc reat it is is suspec t ed and is mild by c linic al c rit eria, c ross- sec t ional imaging is not immediat ely nec essary t o spec if ic ally ev aluat e t he panc reas but may be helpf ul if t he c ause of abdominal pain is unc ert ain. No radiologic ev aluat ion is nec essary if t he pat ient 's c linic al c ourse improv es. How ev er, inv est igat ion of radiographic ally det ec t able pot ent ial c auses of ac ut e panc reat it is suc h as c holelit hiasis (F ig. 15- 74) should c ommenc e as soon as c linic ally f easible. Spec if ic ally , prompt ident if ic at ion of gallst ones is benef ic ial, as st udies hav e show n t hat t he morbidit y of gallst one panc reat it is is reduc ed dramat ic ally t he sooner c holec y st ec t omy is perf ormed (154). US is t he most readily ac c essible and sensit iv e imaging t est f or ident if y ing gallst ones, P.1067 w hic h may not be seen on c ont rast enhanc ed CT (CECT ) due t o t he similar densit y of gallst ones and surrounding bile. MRCP is a v ery sensit iv e t est f or biliary st one det ec t ion (31,276) but is more expensiv e and not as readily av ailable t o emergent ly ev aluat e pat ient s w it h ac ut e panc reat it is. Wit h mild ac ut e panc reat it is pat hologic ally , t here is minimal int erst it ial edema w it h oc c asional mic rosc opic ac inar c ell nec rosis. No mac rosc opic ac inar c ell nec rosis oc c urs, but nec rosis of int ra- and ext rapanc reat ic adipose t issue may oc c ur (23,28,51). Imaging f indings ref lec t t his pat hology . Should c ont rast enhanc ed CT be perf ormed on pat ient s w it h mild panc reat it is, t he panc reas

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2298

15 - The Pancreas and surrounding peripanc reat ic f at may of t en appear normal, or t here may be mild glandular low at t enuat ion indic at ing int erst it ial edema (F ig. 15- 75). T he panc reas is eit her normal appearing or minimally enlarged.

F igure 15- 72 Mild ac ut e panc reat it is in a 57- y ear- old man. Cont rast enhanc ed port al v enous phase 5- mm image t hrough t he t ail of panc reas demonst rat es a small amount of t he peripanc reat ic inf lammat ory st randing, c onsist ent w it h grade C panc reat it is. No glandular nec rosis is ev ident , f or CT sev erit y index (CT SI) of 4.

F igure 15- 73 Sev ere ac ut e panc reat it is sec ondary t o et hanol abuse in a 37y ear- old man. A: Cont rast - enhanc ed port al v enous phase 7- mm c omput ed t omography image demonst rat es absenc e of enhanc ement t hroughout t he majorit y of t he panc reas inv olv ing t he nec k, body , and t ail. B: Port al v enous

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2299

15 - The Pancreas phase image 3.5 c m inf eriorly demonst rat es a minimal amount of enhanc ing panc reat ic glandular t issue in t he head region. Ac ut e f luid c ollec t ion is seen w it hin t he lef t and right ant erior pararenal spac e, and ext ends int o t he t ransv erse mesoc olon. F indings are c onsist ent w it h great er t han 50% gland nec rosis, great er t han t w o f luid c ollec t ions, (Balt hazar E) f or CT sev erit y index (CT SI) of 10.

Severe Acute Pancreatitis On t he ot her hand, CECT is t he mainst ay of imaging in pat ient s w it h sev ere ac ut e panc reat it is, w hic h f requent ly produc es loc al ret roperit oneal c omplic at ions as w ell as shoc k, hy poxemia, respirat ory f ailure, renal f ailure, GI bleeding, and met abolic abnormalit ies. Sev ere ac ut e panc reat it is is most of t en a c linic al expression of panc reat ic glandular nec rosis, w hic h oc c urs w it hin 24 t o 48 hours f rom t he onset of sy mpt oms (21,38,146). Dy namic inc rement al or helic al c ont rast - enhanc ed CT w it h imaging of t he panc reas at peak perf usion (23,28,51,174) is t he gold st andard f or t he c linic al diagnosis of panc reat ic nec rosis, w it h an ac c urac y of 80% t o 90%. As w it h mild panc reat it is, t he CECT f indings in pat ient s w it h sev ere ac ut e panc reat it is mirror t he pat hology . In sev ere ac ut e panc reat it is, c onf luent zones of ac inar c ell and v asc ular nec rosis w it h mic rosc opic and somet imes mac rosc opic duc t al disrupt ion are seen, in addit ion t o ext ensiv e int ra- and ext rapanc reat ic f at nec rosis. T urbid, hemorrhagic f luid may ent er t he ret roperit oneal and perit oneal c av it ies (23).

CT Severity Index in Patients with Acute Pancreatitis Balt hazar et al. (25) f irst at t empt ed in 1985 t o c orrelat e CT f indings in pat ient s w it h ac ut e panc reat it is t o c linic al f ollow - up, morbidit y , and mort alit y (25). In t hose pat ient s w hose init ial CT demonst rat ed one or more peripanc reat ic f luid c ollec t ions (Balt hazar Grade D and E, respec t iv ely ), a P.1068 P.1069 morbidit y rat e of 54% and a mort alit y rat e of 14% w ere doc ument ed, c ompared w it h t hose pat ient s w it h a normal or mildly enlarged panc reas (grades A and B) and t hose w it h mild peripanc reat ic inf lammat ory st randing (grade C), w ho, c ombined, had no mort alit y and only a 4% morbidit y rat e. T his ev aluat ion w as and st ill t oday may be perf ormed w it hout IV c ont rast

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2300

15 - The Pancreas

enhanc ement , but if perf ormed in t his w ay it renders no inf ormat ion about t he presenc e of panc reat ic nec rosis (F ig. 15- 76). A major improv ement in t he CT ev aluat ion of panc reat it is sev erit y w as ac hiev ed w hen Kiv isaari et al. (174) report ed t hat areas of diminished CT at t enuat ion v alues ident if ied on IV c ont rast - enhanc ed inc rement al dy namic CT c orrelat ed w it h surgic ally prov en areas of panc reat ic glandular nec rosis. Subsequent aut hors c onf irmed t he c orrelat ion, demonst rat ing t hat CT has an ov erall sensit iv it y of 100% f or t he det ec t ion of ext ensiv e panc reat ic nec rosis and a sensit iv it y of 50% if only minor nec rot ic areas w ere present at surgery (21). T he ext ent of panc reat ic nec rosis is t he most import ant indic at or of disease sev erit y . Pat ient s w it h less t han 30% glandular nec rosis (F ig. 15- 77) exhibit ed no mort alit y and a 48% morbidit y rat e, w hereas t hose w it h larger areas of nec rosis (30% t o 50% and more t han 50%) w ere assoc iat ed w it h a morbidit y rat e of 75% t o 100% and a mort alit y rat e of 11% t o 25% (26). A CT sc oring sy st em c ombining t he panc reat it is grade and amount of nec rosis w as dev eloped by Balt hazar et al. (21,26) in 1990 in an ef f ort t o prov ide a more ac c urat e imaging prognost ic at or of disease sev erit y . On a sc ale of 1 t o 10, pat ient s w ere assigned 0 t o 4 point s f or grade of panc reat it is A t o E, and t o t his, 2, 4, or 6 point s w ere added, c orresponding t o less t han 30%, 30% t o 50%, or more t han 50% gland nec rosis, respec t iv ely . A CT sev erit y index (CT SI) sc ore of 7 t o 10 y ielded a mort alit y rat e of 17% and a c omplic at ion rat e of 92%. Rec ent ly , modif ic at ions of t he CT SI w ere suggest ed t o inc orporat e imaging ev idenc e of ext rapanc reat ic disease in pat ient s w it h ac ut e panc reat it is. T his simplif ied met hod of assessment c orrelat ed more c losely w it h out c ome paramet ers suc h as lengt h of hospit al st ay and need f or drainage proc edures, w it h a similar int erobserv er v ariabilit y in c alc ulat ion c ompared w it h t he original CT SI (232).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2301

15 - The Pancreas

F igure 15- 74 Gallst one panc reat it is w it h inc reasing sev erit y in a 48- y ear- old w oman. A: Cont rast - enhanc ed port al v enous phase 5- mm c omput ed t omography (CT ) image t hrough t he panc reat ic body and t ail demonst rat es a small amount of inf lammat ory st randing surrounding t he panc reat ic head region superiorly and panc reat ic t ail post eriorly . B: More inf erior image on same day show s small amount of inf lammat ory f luid t rac king int o t he lef t ant erior pararenal spac e. C : Magnet ic resonanc e c holangiopanc reat ography (MRCP) 5c m slab angled c oronal image next day demonst rat es mult if ac et ed low signal dist al c ommon bile duc t st ones (ar r ow s) and mild biliary dilat at ion. D: Axial int rav enous gadolinium- enhanc ed f at - suppressed spoiled gradient ec ho (SPGR)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2302

15 - The Pancreas image show s normal enhanc ement of t he panc reat ic body and t ail, and f luid t rac king ant eriorly w it hin t he ret roperit oneal f at (ar r ow s). Slight ly inf erior

image E: show s f luid w it hin t he ret roperit oneum t rac king int o t he lef t ant erior pararenal spac e. F : One w eek lat er, port al v enous phase c ont rast - enhanc ed CT t hrough t he body and t ail region demonst rat es inc reasing f luid, similar t o t hat seen on t he axial MR images.

F igure 15- 75 Mild ac ut e panc reat it is in a 34- y ear- old man w it h et hanol abuse. Cont rast - enhanc ed port al v enous phase 5- mm image t hrough t he panc reas demonst rat es normal panc reat ic glandular enhanc ement t hroughout , w it h low at t enuat ion f luid surrounding t he panc reas and ext ending int o t he lef t ant erior pararenal spac e. F indings are c onsist ent w it h grade D panc reat it is, no nec rosis, and CT sev erit y index (CT SI) of 5.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2303

15 - The Pancreas

F igure 15- 76 Nonc ont rast panc reat it is ev aluat ion in a 56- y ear- old man w it h renal f ailure w ho present s w it h abdominal pain. A 5- mm oral- c ont rast - only c omput ed t omography image t hrough t he panc reas demonst rat es het erogeneous f luid ext ending in t he lef t ret roperit oneum ant eriorly f rom t he panc reas, surrounding t he desc ending c olon in t he lef t ant erior pararenal spac e. F indings are c onsist ent w it h grade D panc reat it is. No assessment of nec rosis c an be made w it hout int rav enous c ont rast in t his pat ient .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2304

15 - The Pancreas

F igure 15- 77 Ac ut e panc reat it is w it h f oc al, less t han 30% gland nec rosis. Port al v enous phase 5- mm image t hrough t he panc reat ic body demonst rat es f oc al 2 c m area of dec reased enhanc ement at t he body t ail junc t ion. St randy ac ut e f luid is seen w it hin t he ret roperit oneal f at , and ext ends inf eriorly int o t he mesent eric root . F indings are c onsist ent w it h grade D panc reat it is and limit ed nec rosis f or a CT sev erit y index (CT SI) of 5.

P.1070 Rec ommendat ions f or imaging pat ient s w it h ac ut e panc reat it is inc lude an init ial CECT obt ained on present at ion or early in t he w orkup of t he f ollow ing pat ient s: t hose in w hom t he diagnosis is in doubt , t hose w it h hy peramy lasemia and sev ere c linic al panc reat it is, def ined as a pat ient w it h Ranson's sc ore great er t han 3 or APACHE II sc ore great er t han 8, t hose w it h no demonst rable c linic al improv ement af t er 72 hours of c onserv at iv e t herapy , and t hose pat ient s w ho init ially improv ed but t hen suf f ered c linic al det eriorat ion (23). F ollow - up CECT is rec ommended ev ery 7 t o 10 day s in pat ient s w it h sev ere ac ut e panc reat it is or more f requent ly f or c linic al det eriorat ion or f ailure t o show c linic al improv ement . Complic at ions suc h as hemorrhage int o t he c ollec t ion (see F ig. 15- 10), splenic art ery pseudoaneury sm f ormat ion, or c olonic nec rosis are readily depic t ed by CECT . In addit ion, CECT at t he t ime of hospit al disc harge may be usef ul t o c onf irm reasonable resolut ion of t he inf lammat ion and t o est ablish baseline ac ut e f luid c ollec t ions. If t he pat ient is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2305

15 - The Pancreas

unable t o rec eiv e IV iodinat ed c ont rast , a CT using high- densit y oral c ont rast may help def ine t he degree of ac ut e f luid ac c umulat ion but it w ill not render any inf ormat ion regarding t he presenc e of panc reat ic nec rosis. T o reit erat e, t he need f or IV c ont rast during f ollow - up CT is not as c rit ic al and st udies perf ormed w it h oral but no IV c ont rast may be adequat e t o f ollow t he size of a panc reat ic c ollec t ion onc e t he diagnosis of nec rosis has been est ablished (203,354). T he ef f ec t s of IV iodinat ed c ont rast required f or CECT on t he human panc reas are not prec isely know n. Inv est igat ors hav e demonst rat ed delet erious ef f ec t s of IV c ont rast mat erial on t he panc reas in rat s (98,295,349). T hese aut hors show ed t hat iodinat ed c ont rast produc es dec reased t ot al c apillary f low w it hin t he panc reas in rat s w it h experiment ally induc ed panc reat it is and c onc luded t hat IV c ont rast media may c onv ert borderline panc reat ic isc hemia t o irrev ersible nec rosis. T o dat e t here hav e been no prospec t iv e st udies of t hese ef f ec t s in humans. How ev er, a ret rospec t iv e c linic al st udy on pat ient s w it h sev ere panc reat it is show ed t hat t he lengt h of hospit alizat ion and sev erit y of panc reat it is w as w orse in pat ient s w ho had rec eiv ed IV c ont rast medium during CT v ersus t hose w ho had no CT or w ho had CT w it hout IV c ont rast (211). Saif udden et al. (290) f irst suggest ed t hat IV gadolinium- enhanc ed MRI may hav e t he pot ent ial f or demonst rat ing t he presenc e of nec rosis w hen t he pat ient is sc anned early in t he c linic al c ourse of panc reat it is. More rec ent ly , in a st udy c omparing int erobserv er agreement and c orrelat ion of c ont rast enhanc ed CT , nonenhanc ed MRI, and enhanc ed MRI of t he panc reas in pat ient s w it h ac ut e panc reat it is, bet t er linear c orrelat ion bet w een f indings on MRI and pat ient morbidit y rat e, c ompared w it h c ont rast - enhanc ed CT , w as demonst rat ed (183). T he aut hors of t his st udy suggest ed t hat bec ause of t he pot ent ial risk of iodinat ed IV c ont rast t o humans, MRI may be a more prudent means of imaging all pat ient s w it h sev ere ac ut e panc reat it is, espec ially during f ollow - up of f luid c ollec t ions assoc iat ed w it h nec rosis. Unless spec if ic ally c ont raindic at ed due t o sev ere allergic hist ory or ac ut ely elev at ed serum c reat inine, w e c ont inue t o use nonionic iodinat ed IV c ont rast medium in all pat ient s being ev aluat ed f or sev ere ac ut e panc reat it is, We also f eel t hat t he more w idely ac c ept ed and av ailable means of f ollow - up in pat ient s w it h renal dy sf unc t ion, onc e t he init ial c ont rast - enhanc ed CT has been obt ained, is unenhanc ed CT . In pat ient s w it h renal dy sf unc t ion or ot her c ont raindic at ion t o iodinat ed c ont rast , MRI is appropriat e f or ev aluat ion any t ime during t he c ourse of t he pat ient 's illness.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2306

15 - The Pancreas International Symposium on Acute Pancreatitis

A c linic ally based c lassif ic at ion sy st em f or ac ut e panc reat it is w as est ablished during t he Int ernat ional Sy mposium on Ac ut e Panc reat it is held in At lant a, Georgia in 1992 (At lant a Sy mposium). T o f ac ilit at e improv ed c linic al c are of indiv idual pat ient s w it h ac ut e panc reat ic inf lammat ion and t o guide ac ademic ians seeking t o c ompare populat ions w it h t his c omplex disease, expert s in surgery , gast roent erology , pat hology , int ernal medic ine, anat omy , and radiology f rom around t he w orld met and c reat ed st andard def init ions f or f indings in pat ient s w it h mild and sev ere ac ut e panc reat it is. Alt hough ot her radiologic examinat ions may demonst rat e abnormalit ies in pat ient s w it h ac ut e panc reat it is, suc h as pleural ef f usion on c hest radiograph or a dif f usely enlarged and hy poec hoic gland on t ransabdominal sonography , IV c ont rast enhanc ed CT has great ly improv ed and c hanged t he c linic al management of t his c ondit ion bec ause of it s abilit y t o c onsist ent ly and ac c urat ely depic t t he ext ent of loc al panc reat ic injury (21). A monophasic single or mult idet ec t or ac quisit ion of 5- mm t hic k images obt ained t hrough t he abdomen and pelv is in t he port al v enous phase, using high- densit y oral c ont rast , is appropriat e f or ev aluat ion in pat ient s suspec t ed of hav ing ac ut e panc reat it is. F or st aging purposes, more reliable result s are obt ained w hen t he CT is perf ormed 48 t o 72 hours af t er t he onset of an ac ut e at t ac k. T he c ont rast - enhanc ed CT f indings in pat ient s w it h ac ut e panc reat it is and t he spec if ic t y pes of panc reat ic and peripanc reat ic abnormalit ies def ined by t he At lant a Sy mposium (23,28,51) are now desc ribed in f urt her det ail.

Acute Fluid Collections An ac ut e f luid c ollec t ion at t ribut able t o ac ut e panc reat it is is def ined as a c ollec t ion of enzy me- ric h panc reat ic juic e t hat usually dev elops in t he periphery of t he gland, lac ks a w ell- def ined w all, and may dissec t t hroughout t he ret roperit oneum, usually int o t he ant erior pararenal spac es (lef t great er t han right ), t ransv erse mesoc olon, and mesent eric root . T hese c ollec t ions oc c ur early (w it hin 48 hours) in t he c ourse of panc reat it is in 30% t o 50% of pat ient s and resolv e spont aneously 50% of t he t ime (F ig. 15- 78). Conv ersely , t he remainder of t hese ac ut e f luid c ollec t ions may ev olv e ov er t ime and c ont ribut e t o t he f ormat ion of pseudoc y st s, absc esses, or nec rot ic c ollec t ions (F ig. 15- 79). In sev ere ac ut e panc reat it is, t he ac ut e f luid c ollec t ion may be t urbid and hemorrhagic . T he ext ension of t he c ollec t ions t o t he ant erior

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2307

15 - The Pancreas P.1071 P.1072 pararenal spac e may produc e t he Grey T urner's sign, f lank ec c hy mosis, and t he t rac king of f luid int o t he gast rohepat ic and subsequent ly t he f alc if orm

ligament may result in Cullen's sign, periumbilic al ec c hy mosis (220); t hese are c lassic c linic al signs of sev ere ac ut e panc reat it is.

F igure 15- 78 Ac ut e f luid c ollec t ion assoc iat ed w it h sev ere ac ut e panc reat it is in a 38- y ear- old w oman w it h gallst one panc reat it is; spont aneous resolut ion. A: Cont rast - enhanc ed port al v enous phase 5- mm image t hrough t he panc reat ic nec k, body , and t ail demonst rat es a large amount of low at t enuat ion f luid w it hin t he panc reat ic bed, ext ending int o t he lef t ant erior pararenal spac e, as w ell as t he perit oneal c av it y . Small w isps of enhanc ing residual panc reat ic parenc hy ma are ev ident (ar r ow s), but ext ensiv e nec rosis of t he body and t ail is seen. B: T he f luid dissec t ed int o t he mesent eric root inf eriorly , w here t here is some enhanc ement w it hin t he panc reat ic head. F indings are c onsist ent w it h Balt hazar grade E panc reat it is, and great er t han 50% nec rosis, f or CT sev erit y index (CT SI) of 10. C : Cont rast - enhanc ed port al v enous phase 7- mm sc an 6 mont hs lat er demonst rat es resolut ion of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2308

15 - The Pancreas

ac ut e inf lammat ion w it h enhanc ement of t he residual panc reas in t he superior head region. T he panc reas in t he body and t ail region w as no longer ev ident .

F igure 15- 79 Sev ere ac ut e panc reat it is w it h nec rosis ev olv ing ov er a 6mont h period in a 23- y ear- old w oman w it h gallst one panc reat it is. A: Init ial c ont rast - enhanc ed port al v enous phase 5- mm image demonst rat es low densit y ret roperit oneal f luid c ollec t ion replac ing port ions of t he panc reat ic head ant eriorly , w it h f luid ext ending int o t he t ransv erse mesoc olon, right and lef t ant erior pararenal spac es, and perit oneum. F oc al areas of residual enhanc ing panc reas in t he post erior head, t ail, and body regions are present (arrow s). B: One w eek lat er, exc ret ory phase c ont rast - enhanc ed c omput ed t omography (CT ) demonst rat es part ial organizat ion of t he c ollec t ion w it h mult iple sept at ions. C : T w o w eeks lat er, c ont rast - enhanc ed port al v enous phase 7- mm image demonst rat es a more homogeneous appearing f luid c ollec t ion w it hin t he ret roperit oneum, replac ing port ions of t he panc reas t hat underw ent nec rosis on t he init ial CT . T he pat ient remained c linic ally st able. D: Cont rast - enhanc ed port al v enous phase CT 7 mont hs lat er demonst rat es w ell demarc at ed f luid c ollec t ions replac ing t he panc reat ic body ant eriorly and ext ending lat erally f rom t he t ail. At endosc opic drainage, c omponent s w ere c omplet ely liquef ied.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2309

15 - The Pancreas Acute Pseudocyst

An ac ut e pseudoc y st is def ined as a c ollec t ion of panc reat ic juic e c onf ined by a nonepit helialized w all of granulat ion t issue. An ac ut e pseudoc y st oc c urs as a result of ac ut e panc reat it is or t rauma, and requires at least f our w eeks t o f orm (F ig. 15- 80). On IV c ont rast - enhanc ed CT , pseudoc y st s appear as w ell c irc umsc ribed, t hin- w alled, homogeneously low - at t enuat ion c ollec t ions adjac ent t o, or oc c asionally w it hin, an ot herw ise normal appearing panc reas. Pseudoc y st s may produc e sy mpt oms due t o gast ric out let or biliary obst ruc t ion (F ig. 15- 81).

F igure 15- 80 Pseudoc y st c omplic at ing ac ut e panc reat it is in a 27- y ear- old w oman 3 mont hs af t er gallst one panc reat it is. Cont rast - enhanc ed port al v enous phase 5- mm image t hrough t he midabdomen demonst rat es a homogeneous 14 Г— 11 c m f luid c ollec t ion ext ending inf eriorly f rom t he panc reat ic t ail region. Displac ement of t he st omac h superiorly , lef t kidney post eriorly , and t he bow el t o t he right is not ed.

Pancreatic Abscess A panc reat ic absc ess is def ined as a c irc umsc ribed int raabdominal c ollec t ion of pus in c lose proximit y t o t he panc reas (F ig. 15- 82), result ing f rom an episode of ac ut e panc reat it is or t rauma. Like ac ut e pseudoc y st s, t hese c ollec t ions require at least 4 w eeks t o f orm and t y pic ally hav e lit t le or no nec rot ic debris. On CECT , t he w all of a panc reat ic absc ess may appear t hic ker or more

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2310

15 - The Pancreas irregular t han t he w ell delineat ed but t hin w all of t he pseudoc y st , and bot h c ollec t ions hav e a homogeneously low at t enuat ion c ent er.

Pancreatic Necrosis Ac c ording t o t he sy mposium, panc reat ic nec rosis is def ined as dif f use or f oc al area(s) of nonv iable panc reat ic parenc hy ma, w hic h is t y pic ally assoc iat ed w it h peripanc reat ic f at nec rosis. Bec ause dy namic IV c ont rast - enhanc ed CT w as at t he t ime (and remains t oday ) t he gold st andard f or t he c linic al diagnosis of panc reat ic nec rosis, t he def init ion w as also giv en in t erms of imaging. Panc reat ic nec rosis is present w hen t here are one or more f oc al areas of nonenhanc ing panc reat ic parenc hy ma c omprising great er t han 30% of t he gland, as demonst rat ed by dy namic c ont rast - enhanc ed CT . T he nonenhanc ing areas c orrespond t o nonv iable panc reat ic t issue (168). As t he degree of nec rosis inc reases, so does t he spec if ic it y and sensit iv it y of CECT f or it s det ec t ion (21,23,51,354). Alt hough CT sc ans perf ormed t o ev aluat e ac ut e panc reat it is t y pic ally do not inc lude unenhanc ed images t hrough t he panc reas, a homogeneous inc rease t o Hounsf ield numbers of 100 t o 150 should be seen P.1073 in normal glands. Any area of t he panc reas w it h Hounsf ield numbers of ≤30 indic at es dec reased blood perf usion (isc hemia) and c orrelat es w it h t he dev elopment of nec rosis (21). If Hounsf ield unit measurement s are not possible, an est imat e of panc reat ic enhanc ement may be made by c omparing t he at t enuat ion of t he gland t o t he spleen. In t he absenc e of panc reat ic nec rosis, t he panc reas and spleen should be similar in at t enuat ion on port al v enous phase images (see F ig. 15- 72). Pot ent ial pit f alls in t he ident if ic at ion of panc reat ic nec rosis inc lude apparent diminished enhanc ement v alue in pat ient s w it h normal f at t y inf ilt rat ion of t he gland as w ell as in pat ient s w it h dif f use parenc hy mal edema in less sev ere, int erst it ial panc reat it is. Small int rapanc reat ic f oc al f luid c ollec t ions are somet imes P.1074 seen in pat ient s w it h ac ut e panc reat it is and should not be mist aken f or f oc al areas of nec rosis; t his dist inc t ion may not be possible unless prev ious or f ollow up CT images are av ailable f or c omparison (21). Panc reat ic nec rosis t y pic ally is ac c ompanied by gross peripanc reat ic f at nec rosis, but t he rev erse is not t rue. T his phenomenon probably explains t he 22% inc idenc e of loc al c omplic at ions in pat ient s w it hout panc reat ic nec rosis but w it h peripanc reat ic f luid c ollec t ions (201). T he great er t he amount of panc reat ic nec rosis, t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2311

15 - The Pancreas more likely t he panc reat ic duc t w ill be disrupt ed (256), c ont ribut ing t o

inc reased morbidit y and mort alit y . Nec rosis inv olv ing t he nec k and body of t he gland, c ent ral c av it ary nec rosis (29) is f requent ly assoc iat ed w it h duc t disrupt ion (F ig. 15- 83) (28,103,256). Bet w een 20% and 30% of all pat ient s w it h sev ere ac ut e panc reat it is hav e nec rot izing panc reat it is (51). Rev iew of aut opsy and surgic al series indic at e t hat panc reat ic nec rosis and it s c omplic at ions ac c ount f or 70% t o 86% of deat hs f rom ac ut e panc reat it is (256).

F igure 15- 81 Pseudoc y st c omplic at ing ac ut e panc reat it is, leading t o obst ruc t ion of t he c ommon bile duc t . A: Lat e port al v enous phase c omput ed t omography (CT ) image t hrough t he panc reas demonst rat es normal f at t y inf ilt rat ion of t ail and body region. Not e blurred appearanc e of t he int erdigit at ing f at of t he head and nec k due t o ac ut e inf lammat ion, and gallst one (ar r ow ) in t he gallbladder nec k. B: 3 c m inf eriorly , inf lammat ory st randing is seen ext ending f rom t he inf erior panc reat ic head region int o t he mesent eric root , Grade C panc reat it is. C : Eight w eeks lat er, pat ient had persist ent elev at ed bilirubin. Endosc opic ret rograde c holangiopanc reat ography

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2312

15 - The Pancreas spot radiograph w it h injec t ion int o t he dist al c ommon bile duc t demonst rat es smoot h narrow ing of t he low er half of t he bile duc t t hrough t he superior panc reat ic head and suprapanc reat ic regions. T he t ransit ion f rom smoot hly narrow ed t o dilat ed proximal duc t oc c urs at t he lev el of t he sc ope. F aint ly seen panc reat ic duc t appears normal. D: Port al v enous phase CT image af t er endosc opic biliary st ent (ar r ow ) plac ement demonst rat es smoot h round 3.5-

c m pseudoc y st (PC) w it hin t he panc reat ic head, w hic h w as responsible f or t he mass ef f ec t on t he dist al duc t .

F igure 15- 82 Panc reat ic absc ess. A and B: T w o sc ans at a lev el inf erior t o t he body and t ail of t he panc reas show a w ell- def ined f luid c ollec t ion w it h t y pic al c hanges of an absc ess. Gas bubbles are not ed t hroughout t he highv isc osit y pus, w hic h w as subsequent ly drained perc ut aneously suc c essf ully .

F igure 15- 83 T ransduodenal endosc opic drainage of organized panc reat ic nec rosis. A: A 7- mm port al v enous phase c omput ed t omography (CT ) image demonst rat es organized, slight ly het erogeneous c ollec t ion replac ing port ions

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2313

15 - The Pancreas

of t he panc reat ic nec k, body , and t ail. Not e adjac ent relat ionship of t he right border of t he c ollec t ion w it h t he sec ond port ion of t he duodenum, ideal f or t ransduodenal drainage. B: Six w eeks lat er, 5- mm exc ret ory phase CT image demonst rat es c ollapse of t he c av it y around t he t ransduodenal double J st ent s. A t ranspapillary st ent is also in plac e.

P.1075

Infected Pancreatic Necrosis Inf ec t ed nec rosis is def ined as c ult ure posit iv it y of inf ec t ed panc reat ic and/or peripanc reat ic nec rot ic t issue. Inf ec t ion of panc reat ic nec rosis oc c urs in 36% t o 71% of all pat ient s w it h panc reat ic nec rosis (36,52,271) usually oc c urring in t he sec ond t o t hird w eek f ollow ing t he onset of ac ut e panc reat it is (F ig. 1584); t he inf ec t ion is t y pic ally poly mic robial (36). T he dev it alized panc reat ic parenc hy ma is an ideal medium f or inf ec t ion and absc ess f ormat ion (256). Gas bubbles w it hin t he c ollec t ion suggest spont aneous inf ec t ion, but t he absenc e of gas does not exc lude inf ec t ion of t he nec rosis. Likew ise, spont aneous f ist ulizat ion t o bow el may int roduc e air int o a prev iously st erile nec rot ic c ollec t ion (F ig. 15- 85). Perc ut aneous aspirat ion of t he nec rot ic c ollec t ion f or Gram st ain and c ult ure using sonographic or CT guidanc e (F ig. 15- 86) is of t en nec essary t o dist inguish bet w een inf ec t ed and st erile panc reat ic nec rosis. T his proc edure is saf e and ac c urat e, w it h a sensit iv it y of 96% and a spec if ic it y of 99% (23), and is rec ommended in pat ient s w it h nec rot izing panc reat it is w ho c linic ally det eriorat e or f ail t o improv e, bec ause it may be impossible t o dist inguish t hese t w o ent it ies c linic ally . In a rec ent st udy ev aluat ing t he role of gallium single phot on emission c omput ed t omography (SPECT ) imaging in a populat ion of pat ient s w it h sev ere ac ut e panc reat it is, upt ake w as seen in 18 of 18 pat ient s w it h inf ec t ed panc reat ic c ollec t ions (inf ec t ed nec rosis or absc esses), and in none of 5 pat ient s w it h st erile panc reat ic c ollec t ions. No c orrelat ion bet w een t he presenc e or absenc e of nec rosis and gallium av idit y w as f ound. T he aut hors of t his st udy suggest t hat gallium SPECT may be a usef ul adjunc t t o CT in t he ev aluat ion of pat ient s w it h sev ere ac ut e panc reat it is, espec ially t o help guide int erv ent ion (351).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2314

15 - The Pancreas

F igure 15- 84 Inf ec t ed panc reat ic nec rosis in a 60- y ear- old man w it h 1 w eek hospit alizat ion f or sev ere ac ut e panc reat it is. Port al v enous phase 5- mm c omput ed t omography image demonst rat es a 12 Г— 7 c m het erogeneous, gas c ont aining c ollec t ion replac ing t he panc reas ant erior t o t he splenic v ein (ar r ow ), c onsist ent w it h inf ec t ed panc reat ic nec rosis.

F igure 15- 85 Sev ere subac ut e panc reat it is w it h spont aneous gas in a 79y ear- old w oman. A: Cont rast - enhanc ed port al v enous phase c omput ed t omography (CT ) image t hrough t he panc reas rev eals a f oc al segment of enhanc ing panc reat ic body , w it h a part ially sept at ed het erogeneous f luid c ollec t ion replac ing t he nec k and superior head region. F indings are c onsist ent w it h subac ut e nec rot ic c ollec t ion, panc reat it is grade D, w it h 30% t o 50% nec rosis, indic at ing CT sev erit y index (CT SI) of 7. B: Cont rast - enhanc ed port al v enous phase 8 day s lat er, w it hout drainage t herapy , demonst rat es

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2315

15 - The Pancreas

marked reduc t ion in size of c ollec t ion, w hic h now c ont ains an air–f luid lev el. T his likely represent s spont aneous f ist ulizat ion t o bow el and part ial ev ac uat ion.

T he t reat ment of pat ient s w it h ac ut e nec rot izing panc reat it is c ont inues t o ev olv e sinc e t he At lant a Sy mposium. As c onserv at iv e medic al management of pat ient s w it h panc reat ic nec rosis has gained popularit y ov er t he past dec ade, more pat ient s w ho surv iv e t he ac ut e ev ent of sev ere nec rot izing panc reat it is and require no immediat e t herapeut ic surgic al or radiologic int erv ent ions, f requent ly undergo repeat imaging. T he serial CECT s in t hese pat ient s demonst rat e ev olut ion of t he ac ut e panc reat ic nec rosis and ac ut e f luid c ollec t ions t o a more organized, part ially enc apsulat ed, mult isept at e st at e (see F ig. 15- 79) (33,256). Af t er t he init ial CECT , nec rosis (w het her st erile or inf ec t ed) P.1076 most c ommonly produc es a low at t enuat ion or near f luid densit y c ollec t ion replac ing a port ion of t he panc reas. T he c ollec t ions oc c upy and expand w it hin t he panc reat ic bed and, rat her t han being loc at ed in a peripanc reat ic loc at ion, replac e port ions of t he gland w hic h init ially demonst rat ed nec rosis (F igs. 1583 and 15- 87). T he low at t enuat ion of t he c ollec t ions on t hese lat er CECT s may of t en be misleading in t hat ext ensiv e residual solid nec rot ic debris may not be disc ernible unt il nonsurgic al drainage is undert aken, and t he liquef ied port ion of t he c ollec t ion is remov ed.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2316

15 - The Pancreas

F igure 15- 86 Comput ed t omography (CT ) guided needle aspirat ion f or pot ent ial inf ec t ed panc reat ic nec rosis. A: Lat e port al v enous phase 7- mm CT image demonst rat es ac ut e f luid c ollec t ion, w it h lit t le enhanc ement of t he panc reat ic body and t ail. B: More c audal image at t he lev el of t he splenic v ein and port al c onf luenc e rev eals larger het erogeneous ac ut e f luid c ollec t ion w it h minimal enhanc ement of t he panc reat ic head. F indings are c onsist ent w it h grade D panc reat it is, great er t han 50% nec rosis, CT sev erit y index (CT SI) of 9. C : T hree w eeks lat er on support iv e t herapy , t he pat ient 's c ondit ion det eriorat ed. A 10- mm axial CT image demonst rat es t he t ip of a spinal needle w it hin t he c ollec t ion, w it h mat erial aspirat ed f or Gram st ain and c ult ure.

T he dist inc t ion bet w een t his subac ut e t y pe of nec rot ic c ollec t ion, ref erred t o as organized panc reat ic nec rosis by Baron et al., and pseudoc y st s is import ant , regardless of t it le. Near univ ersal f ailure of drainage (inc luding endosc opic , perc ut aneous, and ev en c losed surgic al drainage) oc c urs w hen part ially liquef ied nec rot ic c ollec t ions are mist aken f or t y pic al ac ut e pseudoc y st s (34,128,185,203). T his is due t o t he inabilit y t o remov e solid

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2317

15 - The Pancreas debris t hrough st andard drainage c at het ers. T hus, bef ore labeling a low at t enuat ion panc reat ic c ollec t ion as a pseudoc y st , a diligent searc h f or

ev idenc e of panc reat ic nec rosis should be made and of t en requires ev aluat ion of prior sc ans. T he presenc e of nec rosis is est ablished by dec reased enhanc ement of t he panc reas on t he init ial CECT , and subsequent ev olut ion of ac ut e f luid c ollec t ions and nonenhanc ing panc reas t o a bet t er def ined low at t enuat ion (of t en homogeneous) c ollec t ion r eplac ing t he panc reas. Morgan et al. demonst rat ed t hat MRI w as more ac c urat e t han CECT f or demonst rat ing t he c omplex nat ure of “ f luid” c ollec t ions assoc iat ed w it h sev ere ac ut e panc reat it is (229). F at suppressed T 2- w eight ed spin ec ho MR images depic t t he gross solid and liquef ied c omponent s of panc reat ic nec rosis in t he subac ut e set t ing, and require no c ont rast (F igs. 15- 87 and 15- 88). MRI may be most helpf ul as an adjunc t t o CECT in pat ient s in w hom nec rosis is suspec t ed and drainage is c ont emplat ed.

F igure 15- 87 Organized panc reat ic nec rosis in a 21- y ear- old w oman w it h gallst one panc reat it is, ref erred f or “ pseudoc y st drainage.” A: Cont rast enhanc ed c omput ed t omography of t he abdomen approximat ely 8 w eeks af t er onset of panc reat it is demonst rat es a homogeneous w ell enc apsulat ed f luid c ollec t ion ant erior t o t he splenic v ein. B: Prior t o drainage, T 2- w eight ed f at suppressed magnet ic resonanc e image of t he same region demonst rat es marked het erogeneit y w it hin t he c ollec t ion, w it h high signal f luid as w ell as large areas of low signal sof t t issue c onsist ent w it h persist ent solid debris.

P.1077

Pancreatic Hemorrhage

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2318

15 - The Pancreas Panc reat ic nec rosis is of t en hemorrhagic bec ause of leakage f rom small v eins (256). CT w ill demonst rat e areas of inc reased at t enuat ion w it hin t he panc reat ic or peripanc reat ic c ollec t ion (see F ig. 15- 10). Pseudoaneury sms may f orm w hen art erial w alls are af f ec t ed by nec rosis or aut odigest iv e enzy mes. Cat ast rophic bleeding may oc c ur, leading t o deat h.

Computed Tomography Guidance for Pancreatic Interventions In addit ion t o delineat ing a pat hw ay f or perc ut aneous needle aspirat ion of nec rot ic c ollec t ions or absc esses f or Gram st ain and c ult ure, CT may be used bef ore, during, and af t er panc reat ic int erv ent ions. Drainage of t he v ariet y of c ollec t ions t hat may arise f rom ac ut e panc reat it is may be perf ormed perc ut aneously , endosc opic ally , surgic ally , or by a c ombinat ion of approac hes. A meaningf ul disc ussion of panc reat ic int erv ent ional opt ions is bey ond t he sc ope of t his c hapt er, but sev eral inf ormat iv e ref erenc es are av ailable (1,23,30,33,34,38,52,88,103,185,271,344,345). Prior t o drainage, CT readily demonst rat es t he loc at ion, size, and relat ionship of t he c ollec t ion t o adjac ent c rit ic al st ruc t ures. In t he c ase of perc ut aneous drainage, CT guidanc e may be used during plac ement of one or more c at het ers. When endosc opic drainage is used CT is c rit ic al in demonst rat ing t he approximat ion of t he c ollec t ion t o t he int est inal lumen (gast ric or duodenal) t hrough w hic h c at het ers may be plac ed (see F ig. 15- 83). T he presenc e of loc ulat ions, sept at ions, and solid debris w hen depic t ed on CT immediat ely prior t o c at het er plac ement may alt er how many and w hat c aliber c at het ers and or st ent s are used (see F ig. 15- 88). Again, in t he c ase of nec rot ic c ollec t ions, CT may underest imat e t he c omplexit y of t he c ollec t ions, and w hen a pat ient 's original CT demonst rat es signif ic ant unenhanc ed panc reat ic glandular t issue, t he phy sic ian perf orming t he drainage must be made aw are t hat t he pot ent ial f or solid debris is present . Ov er t ime, as liquef ac t ion oc c urs t he relat iv e amount of solid debris w it hin t he c ollec t ion dec reases. Hist oric ally , surgeons perf orming nec rosec t omies at t empt ed t o w ait 4 t o 6 w eeks af t er onset of nec rot izing panc reat it is, if c linic ally possible, t o allow nec rot ic t issues t o undergo liquef ac t iv e nec rosis (F ig. 15- 89) and make t he dist inc t ion bet w een dead and v iable t issue more apparent at operat ion. Onc e a drainage proc edure has been perf ormed, f ollow - up CT is c rit ic al in assessing t he suc c ess of t he proc edure. T he presenc e of residual solid debris

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2319

15 - The Pancreas may prompt more aggressiv e irrigat ion of t he c av it y , addit ional perc ut aneous or endosc opic proc edures, or surgery . Complet e ev ac uat ion of t he c ollec t ion may be c onf irmed onc e drain out put diminishes. Reac c umulat ion of f luid demonst rat ed on CT af t er c at het ers hav e been remov ed may suggest duc t al c ommunic at ion w it h t he c ollec t ion, a c ondit ion t hat renders c ure by perc ut aneous met hods dif f ic ult (256). In general, t he dev elopment of a persist ent panc reat ic oc ut aneous f ist ula af t er perc ut aneous drainage of panc reat ic f luid c ollec t ions c orrelat es w it h t he sev erit y of t he panc reat it is init ially (101). F requenc y and lengt h f or f ollow - up CT af t er int erv ent ions

depend on t he t y pe of c ollec t ion. Collec t ions suc h as t y pic al pseudoc y st s may be c omplet ely ev ac uat ed w it hin day s (185), w hereas nec rot ic c ollec t ions may require drainage int erv als of sev eral mont hs' durat ion (103). F oc al parenc hy mal def ec t s, f ist ulae, and pseudoaneury sm f ormat ion (F ig. 15- 90) are w ell depic t ed on CT af t er t he ac ut e episode subsides. P.1078

Magnetic Resonance Imaging in Acute Pancreatitis T he diagnosis of ac ut e panc reat it is on MR images relies on t he presenc e of morphologic c hanges, muc h t he same as CT (300). In mild c ases, t he panc reas may appear normal or slight ly enlarged. Homogeneous high signal is present t hroughout t he gland on T 1 f at - suppressed images. St randy peripanc reat ic f luid may be demonst rat ed as low signal int ensit y on a bac kground of highint ensit y ret roperit oneal f at on nonc ont rast spoiled GRE images, or c onv ersely as high signal int ensit y st rands of f luid surrounding t he low signal panc reas on a bac kground of low signal int ensit y ret roperit oneal f at on T 2 f at suppressed images (see F ig. 15- 74). In c ases of sev ere ac ut e panc reat it is, t he presenc e of f luid is similarly demonst rat ed. In addit ion, panc reat ic nec rosis may be ev aluat ed w it h dy namic IV gadolinium- enhanc ed T 1 f ast spoiled gradient images, w it h areas of nonenhanc ement c orresponding t o areas of gland nec rosis (183,290,348).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2320

15 - The Pancreas

F igure 15- 88 Organized panc reat ic nec rosis magnet ic resonanc e c holangiopanc reat ography (MRCP) in a 42- y ear- old man, 8 w eeks af t er onset ac ut e panc reat it is, w it h f ailure t o t hriv e. A: A 2.5- c m angled c oronal half F ourier ac quisit ion single- shot t urbo spin ec ho (HAST E) MRCP image demonst rat es an 8 Г— 10 c m het erogeneous f luid signal c ollec t ion in midline, t o t he right of t he slight ly dilat ed c ommon bile duc t . A port ion of normal c aliber panc reat ic duc t in t he t ail is ev ident (ar r ow ). Het erogeneous nat ure of t he c ollec t ion is c onsist ent w it h f luid and residual nec rot ic debris. B: T hin

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2321

15 - The Pancreas sec t ion HAST E angled c oronal image show s relat ionship of panc reat ic duc t in t he t ail t o t he c ollec t ion, and more irregularit y of t he solid debris along t he

inf erior margin. C : Axial int rav enous gadolinium enhanc ed f ast spoiled gradient (F SPGR) f at - suppressed T 1- w eight ed gradient breat hhold image demonst rat es organized panc reat ic nec rot ic c ollec t ion replac ing t he superior panc reat ic head, nec k, and body , w it h residual normal panc reat ic t issue seen in t he t ail. D: Spot radiograph during endosc opic drainage show s t w o double J t ransgast ric st ent s and nasal panc reat ic irrigat ion c at het er, t y pic ally used f or endosc opic drainage of c omplex c ollec t ions assoc iat ed w it h panc reat ic nec rosis. E: One mont h lat er af t er t ransgast ric endosc opic drainage, t he size of t he c ollec t ion has been markedly reduc ed w it h only a small amount of f luid seen surrounding t he panc reat ic port ion of t he double J st ent s.

P.1079 More rec ent ly , Lec esne et al. (183) report ed exc ellent c orrelat ion of nec rosis diagnosed on c ont rast - enhanc ed MR c ompared w it h c ont rast - enhanc ed CT . Int erest ingly , in t his same st udy , nonenhanc ed MR images w it h f oc al areas of nec rosis def ined as w ell- marginat ed areas of signal int ensit y dif f erent f rom t he signal int ensit y of t he normal panc reas also c orrelat ed w ell w it h areas of nec rosis seen on CT and c ont rast - enhanc ed MR images. T he c alc ulat ion of sev erit y based on panc reat ic f luid and nec rosis (in a met hod similar t o t he Balt hazar CT SI) w as reproduc ible on MRI and, as prev iously ment ioned, c orrelat ed w it h pat ient out c ome more c losely t han t he CT SI. Het erogeneit y of ac ut e f luid c ollec t ions manif est ing as high signal on bot h T 1- and T 2- w eight ed images may be due t o prot einac eous mat erial or hemorrhage (34,183). T he c omplexit y of nec rot ic panc reat ic f luid c ollec t ions in t he ac ut e and subac ut e st ages is muc h bet t er demonst rat ed w it h MRI c ompared w it h CT (see F igs. 1586 and 15- 87) (229). Key adv ant ages t o MRI in t he ev aluat ion of ac ut e panc reat it is inc lude t he lac k of radiat ion and pot ent ial benef it of lac k of nephrot oxic it y in t hese pat ient s, w ho are of t en y oung and may require mult iple sc ans (224).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2322

15 - The Pancreas

F igure 15- 89 Organized panc reat ic nec rosis in a 48- y ear- old man 8 w eeks af t er onset sev ere ac ut e panc reat it is w it h f ailure t o t hriv e. A 5- mm port al v enous phase c omput ed t omography image demonst rat es v ery large predominant ly low at t enuat ion c ollec t ion replac ing t he panc reas. Not e t he low at t enuat ion ret roperit oneal f at and f aint ly v isible residual panc reas w it hin t he c ollec t ion. T here is marked narrow ing of t he gast ric out let , but oral c ont rast does pass int o t he bow el. Bec ause of t he pat ient 's sy mpt oms, limit ed surgic al nec rosec t omy t hrough t he post erior gast ric w all w as perf ormed; approximat ely 1000 c c dark liquid and sev eral grams of nec rot ic debris w ere remov ed.

F igure 15- 90 Post panc reat it is splenic art ery pseudoaneury sm. A: Wellc irc umsc ribed, ov oid, 4 Г— 2 c m st ruc t ure is seen ant erior t o t he body of t he panc reas on prec ont rast c omput ed t omography (CT ). T he c urv ilinear high

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2323

15 - The Pancreas densit y w it hin t he right aspec t of t he lesion represent s f resh c lot . B: Cont rast - enhanc ed CT t hrough t he same lev el demonst rat es enhanc ement of blood w it hin t he lumen of t he pseudoaneury sm, surrounded by c lot .

Duc t al st ruc t ures are exc ellent ly depic t ed w it h MRCP t ec hniques (31,119,276,311) and may be usef ul f or t he P.1080 ident if ic at ion of c holedoc holit hiasis in c ases of gallst one panc reat it is (see F ig. 15- 74) or ident if ic at ion of st ruc t ural anomalies in pat ient s w it h panc reas div isum. Wit h sec ret in st imulat ion, t hin, normal main panc reat ic duc t s and side branc hes may be v isualized. IV sec ret in injec t ion st imulat es t he exoc rine panc reas t o sec ret e f luid and bic arbonat e, result ing in a t ransient inc rease in main panc reat ic duc t diamet er, improv ing v isualizat ion. T he dist ension of normal duc t s is helpf ul in ident if y ing panc reas div isum (108,129,205). MRCP using single- shot half - F ourier rapid ac quisit ion relaxat ion enhanc ement (RARE) t ec hniques (108) is ideally c arried out during t he f irst 5 minut es af t er sec ret in injec t ion. Bey ond t his t ime, t he high signal of f luid ent ering t he duodenum f rom t he panc reat ic duc t on t he heav ily T 2- w eight ed images may obsc ure t he duc t al st ruc t ures. T he degree of f illing of t he duodenum w it h f luid has been used t o est imat e panc reat ic exoc rine f unc t ion (205,208).

Chronic Pancreatitis Chronic panc reat it is is a disease of prolonged panc reat ic inf lammat ion and f ibrosis c harac t erized by irrev ersible morphologic and/or f unc t ional abnormalit ies (292,316). T he hist ologic c hanges inc lude f ibrosis and at rophy of glandular element s. Ac c ording t o t he rev ised c lassif ic at ion of panc reat it is f rom t he Marseilles sy mposium of 1984, ac ut e and c hronic panc reat it is are v ery dif f erent diseases and only rarely does ac ut e panc reat it is lead t o c hronic panc reat it is. T here is a st rong assoc iat ion bet w een alc ohol abuse and c hronic panc reat it is. It is post ulat ed t hat w hen t he f irst bout of c linic al panc reat it is oc c urs in pat ient s w ho are alc oholic s of 6 y ears durat ion or great er, t he panc reas is already dif f usely sc arred, and t he init ial bout of alc oholic panc reat it is ac t ually heralds t he onset of c hronic panc reat it is (189,268,291). In addit ion t o c hronic alc oholic panc reat it is, c hronic panc reat it is is f ound w it h f amilial oc c urrenc e in kindred w it h hy perlipidemia, hy perparat hy roidism, c y st ic f ibrosis (CF ), and c holelit hiasis (163). Addit ionally , t here is a f amilial f orm of panc reat it is t ermed heredit ary panc reat it is t hat is t hought t o be inherit ed in

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2324

15 - The Pancreas an aut osomal dominant f ashion w it h v ariable penet ranc e. T he t y pic al c linic al

f eat ures inc lude an early age of onset , w it h v ary ing degrees of abdominal pain and disabilit y . Complic at ions of endoc rine and exoc rine panc reat ic insuf f ic ienc y , pseudoc y st f ormat ion, and adenoc arc inoma of t he panc reas may dev elop. T he hallmark f inding in t his f orm of panc reat it is is t he presenc e of v ery large c alc uli w it hin dilat ed panc reat ic duc t s, v isible on plain radiographs of t he abdomen in c hildhood (163,281). Chronic panc reat it is c aused by hy perparat hy roidism and panc reas div isum (230) may also be assoc iat ed w it h int raduc t al c alc uli. Ot her c auses of panc reat it is, inc luding gallst ones, drugs, t rauma, and v iruses, do not c harac t erist ic ally c ause panc reat ic c alc if ic at ions (187). T he pat hognomonic f eat ures on CT in pat ient s w it h c hronic panc reat it is are sc at t ered glandular and duc t al c alc if ic at ions and duc t al dilat at ion (F igs. 15- 91 and 15- 92). T he int raduc t al c alc if ic at ions arise f rom prot einac eous plugs t hat ac c umulat e c alc ium c arbonat e and range in size f rom mic rosc opic (F ig. 15- 93) t o great er t han 1 c m (187). In a ret rospec t iv e analy sis of 56 pat ient s w it h doc ument ed c hronic panc reat it is st udied w it h c ont rast - enhanc ed CT examinat ions, dilat at ion of t he main panc reat ic duc t w as seen in 68% of c ases, parenc hy mal at rophy in 54%, panc reat ic c alc if ic at ions in 50%, f luid c ollec t ions in 30%, f oc al panc reat ic enlargement in 30%, biliary duc t al dilat at ion in 29%, and alt erat ions in peripanc reat ic f at or f asc ia in 16%. In only 7% of t he pat ient s w ere no abnormalit ies det ec t ed (197). As st at ed prev iously , smoot h or beaded dilat at ion of t he main panc reat ic duc t is most c ommonly assoc iat ed w it h c arc inoma, w hereas irregular dilat at ion is more f requent ly seen in c hronic panc reat it is. F urt hermore, a rat io of duc t w idt h t o t ot al gland w idt h of less t han 0.5 f av ors t he diagnosis of c hronic panc reat it is (see F ig. 15- 31) (162). Morphologic c hanges f requent ly result in a shrunken and at rophic gland surrounding t he dilat ed duc t . How ev er, t he panc reas is oc c asionally enlarged, and c hronic panc reat it is c an ev en present as a f oc al, nonc alc if ied mass t hat by all CT c rit eria w ould be indist inguishable f rom a c arc inoma (see F ig. 15- 35) (180,237). In a rec ent st udy c orrelat ing CT and MRI f eat ures in pat ient s w it h c hronic panc reat it is present ing as a f oc al mass, f our of sev en pat ient s had isoat t enuat ion of t he f oc al mass and t he remaining panc reat ic t issue on all helic al CT sequenc es, inc luding unenhanc ed, dy namic panc reat ic phase and port al v enous phase images. Pat hologic ev aluat ion of t he mass and t he remaining nonenlarged panc reat ic parenc hy ma rev ealed a similar degree of f ibrosis in bot h areas of t he gland. In t he same

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2325

15 - The Pancreas

st udy , t hree of sev en pat ient s had f oc al masses t hat w ere v isibly demarc at ed as hy poat t enuat ing on t he panc reat ic phase images and similar in densit y t o t he remainder of t he panc reas on port al v enous phase images. In t hese pat ient s, pat hologic ev aluat ion rev ealed no f ibrosis in t he nonenlarged port ion of t he panc reas and t y pic al f ibrosis, inf ilt rat ion of ly mphoc y t es, and reduc t ion in glandular element s in t he masslike port ion (171). EUS may aid in dif f erent iat ing f oc al masses due t o panc reat it is f rom c anc er. EUS is equiv alent t o ERCP in ident if y ing adv anc ed c hronic panc reat it is and is more sensit iv e t han ERCP in early st ages bec ause it det ec t s parenc hy mal c hanges not v isible by ot her t ec hniques (157), inc luding morphologic f eat ures of ec ho- int ense sept a/ ec ho- reduc ed f oc i (pseudolobularit y ), duc t al irregularit ies, and c alc if ic at ions [sensit iv it y 97%, spec if ic it y 60%, posit iv e predic t iv e v alue (PPV) 94%, negat iv e predic t iv e v alue (NPV) 75%—w it h EUS- f ine needle biopsy , NPV inc reases t o 100% (135)]. Chronic panc reat it is also c an be assoc iat ed w it h obst ruc t ion of t he biliary t ree. In most inst anc es, t he lumen of t he obst ruc t ed bile duc t t apers gradually (see F ig. 15- 34), in c ont rast t o an abrupt t ransit ion c ommonly assoc iat ed w it h neoplasm. In an analy sis of 51 pat ient s w it h c hronic alc oholic panc reat it is and c ommon duc t obst ruc t ion, an P.1081 elev at ed serum alkaline phosphat ase lev el w as t he most c ommon abnormal laborat ory f inding (14). T he elev at ion in serum bilirubin lev el w as nev er progressiv e; a rising and f alling pat t ern w as most of t en enc ount ered. A c ombinat ion of CT ev aluat ion show ing a gradually diminishing duc t diamet er on suc c essiv e images t ow ards t he ampulla, and c holangiography by eit her ERCP or MRCP, c orrelat ed w it h t he c linic al laborat ory f indings, generally w ill permit dif f erent iat ion of t his t y pe of bile duc t obst ruc t ion sec ondary t o panc reat it is f rom t hat due t o neoplasm.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2326

15 - The Pancreas

F igure 15- 91 Classic sev ere c hronic panc reat it is. A: Spot radiograph prior t o endosc opic ret rograde c holangiopanc reat ography demonst rat es mult iple c oarse c alc if ic at ions in t he midline upper abdomen, in a dist ribut ion c onsist ent w it h panc reat ic c alc if ic at ions and c hronic panc reat it is. B: A 5- mm oral- c ont rast only c omput ed t omography image demonst rat es marked dilat at ion of t he main panc reat ic duc t in t he nec k and numerous large c alc if ic at ions t hroughout t he gland. C : Spot radiograph during injec t ion of t he panc reat ic duc t demonst rat es sev ere dilat at ion of t he main duc t and side branc hes w it h f oc al f illing def ec t s near t he ampulla c onsist ent w it h int raduc t al c alc uli.

Pseudoc y st s c an oc c ur in bot h ac ut e panc reat it is and c hronic panc reat it is (F ig. 15- 94), but hav e v ery dif f erent origins. When pseudoc y st s are f ound in assoc iat ion w it h duc t al dilat at ion and int raduc t al c alc if ic at ion, c hronic panc reat it is is t he underly ing disease (F ig. 15- 95). Along w it h hemorrhage and superinf ec t ion, anot her major c omplic at ion of pseudoc y st f ormat ion is spont aneous rupt ure. Pseudoc y st s may rupt ure int o t he perit oneal c av it y (w it h t he dev elopment of asc it es), t he ext raperit oneal spac es, t he pleural c av it y , or t he GI t rac t . Panc reat ic o- pleural f ist ulas (F ig. 15- 96)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2327

15 - The Pancreas P.1082 are most of t en assoc iat ed w it h c hronic alc oholic panc reat it is, and in t hese c ases t he pat ient s present more of t en w it h c hest sy mpt oms t han w it h abdominal sy mpt oms. Endosc opic ret rograde panc reat ography c ombined w it h CT c an generally delineat e t he c ause f or t he rec urrent pleural ef f usion

(209,280,341) or ev en a muc h rarer c omplic at ion, panc reat ic obronc hial f ist ula (74). When c ommunic at ion w it h t he lumen of t he bow el is est ablished, gas may be seen w it hin t he pseudoc y st and w ill not nec essarily be an indic at ion of a gas f orming inf ec t ion (216,337).

F igure 15- 92 Chronic panc reat it is w it h obst ruc t ing st one. Curv ed planar ref ormat t ed image aligned w it h t he main panc reat ic duc t show s t he large obst ruc t ing c alc ulus w it hin t he duc t in t he nec k region.

Pseudoc y st s c an be c onf used w it h c y st ic or nec rot ic t umors, a markedly dilat ed and t ort uous panc reat ic duc t (see F ig. 15- 95), or a t rue or f alse aneury sm of an int rapanc reat ic or peripanc reat ic art ery . Cy st ic t umors usually oc c ur in pat ient s w it hout a hist ory of panc reat it is and may show c harac t erist ic CT f indings, as prev iously desc ribed. Nec rot ic t umors generally hav e t hic k and irregular w alls t hat rarely c alc if y , c ompared w it h t he unif orm and oc c asionally c alc if ied w alls of pseudoc y st . Aneury sms or f alse aneury sms c harac t erist ic ally w ill be enhanc ed f ollow ing an IV bolus of c ont rast mat erial.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2328

15 - The Pancreas Ev en prior t o administ rat ion of c ont rast mat erial, t he similarit y bet w een t he densit y of t he f luid in t he f alse aneury sm and t he densit y of t he blood in t he aort a or v ena c av a w ill be a c lue t o it s nat ure. Aneury sms or f alse aneury sms c an also be diagnosed by MRI and pulsed Doppler US w it hout t he use of IV c ont rast agent s. Chronic panc reat it is may be assoc iat ed w it h splenic and port al v enous

obst ruc t ion (F ig. 15- 97). In a rev iew of 266 pat ient s w it h c hronic panc reat it is w ho w ere f ollow ed up f or a mean t ime of 8.2 y ears, splenic and port al v enous obst ruc t ion w as f ound in 35 pat ient s (13.2%) but w as sy mpt omat ic in only t w o. Obst ruc t ion inv olv ed t he splenic v ein in 22 pat ient s, t he port al v ein in 10, and t he superior mesent eric v ein in 3. T he aut hors c onc luded t hat P.1083 P.1084 in c hronic panc reat it is, splenic and port al v enous obst ruc t ion should be sy st emat ic ally sought in pat ient s w it h ac ut e problems or pseudoc y st s, espec ially if t herapeut ic dec isions w ould be modif ied by a diagnosis of v enous obst ruc t ion. T he dat a also show ed t hat t he risk of GI v aric eal bleeding w as low er t han prev iously report ed (41). Splenic v ein int errupt ion and gast roepiploic v aric es are easily depic t ed w it h CT .

F igure 15- 93 Less sev ere c hronic panc reat it is in a 51- y ear- old man. A: Spot radiograph during endosc opic ret rograde c holangiopanc reat ography (ERCP) w it h injec t ion int o t he panc reat ic duc t rev eals ac inarizat ion of t he head and nec k w it h abrupt t erminat ion of t he panc reat ic duc t in t he body . T here is irregularit y of t he main panc reat ic duc t , dilat at ion and irregularit y of t he side branc hes. How ev er, t he abrupt t erminat ion of t he duc t c ould be due t o c hronic panc reat it is st ric t ure or mass. B: A 7- mm port al v enous phase

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2329

15 - The Pancreas c omput ed t omography image demonst rat es a 3- mm f oc al c alc if ic at ion in t he panc reat ic body , c orresponding t o t he sit e of duc t c ut of f on ERCP. Not e dilat at ion of t he main panc reat ic duc t in t he t ail, upst ream f rom t he c alc if ic at ion. Peripanc reat ic pseudoc y st s (PC) are also present .

F igure 15- 94 Chronic panc reat it is w it h pseudoc y st dissec t ing int o t he superior rec ess lesser sac . A 7- mm port al v enous phase c omput ed t omography image demonst rat es w ell- def ined f oc al f luid c ollec t ion w it hin t he pot ent ial spac e of t he perit oneal f olds c reat ing t he superior rec ess of t he lesser sac , produc ing some adjac ent mass ef f ec t on t he hepat ic parenc hy ma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2330

15 - The Pancreas

F igure 15- 95 Chronic panc reat it is w it h pseudoc y st dissec t ing int o w all of st omac h. A: A 5- mm oral- c ont rast - only c omput ed t omography (CT ) image t hrough t he upper abdomen demonst rat es w ell- c irc umsc ribed 8 Г— 7 c m f luid c ollec t ion dissec t ing w it hin t he post erior gast ric w all. B: 4 c m inf eriorly , inf lammat ory c hange is seen surrounding t he superior panc reat ic body , w hic h c ont ains sev eral low at t enuat ion c ollec t ions represent ing eit her int rapanc reat ic pseudoc y st s or dilat ed duc t . No c alc if ic at ions are not ed. C : Spot radiograph f rom endosc opic ret rograde c holangiopanc reat ography (ERCP) w it h injec t ion int o t he major papilla show s irregularit y of t he nondilat ed main panc reat ic duc t w it h sev eral f oc al st ric t ures and t w o areas of ext rav asat ion int o c omplex t rac ks, likely leading t o t he pseudoc y st s seen on CT . By Cambridge c lassif ic at ion, t his represent s sev ere c hronic panc reat it is.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2331

15 - The Pancreas

F igure 15- 96 Chronic panc reat it is w it h panc reat ic o- pleural f ist ula. A: A 7- mm port al v enous phase c omput ed t omography (CT ) image t hrough t he superior panc reat ic head lev el demonst rat es an ov oid 2.5 (1.5 c m f luid c ollec t ion in t he panc reat ic nec k. Not e f luid also dissec t ing around t he lef t hepat ic lobe. B: A 7- mm CT image loc at ed 8 c m superior t o t he panc reat ic nec k demonst rat es w ell- def ined t rac k of f luid in t he post erior mediast inum. C : 15 c m superiorly t o A, f oc al t ubular f luid c ollec t ions in t he post erior mediast inum hav e t rac ked f urt her int o t he c hest . Not e part ial loc ulat ion of pleural f luid w it hin t he right hemit horax. Communic at ion bet w een t he panc reat ic duc t , ret roperit oneal and post erior mediast inal f luid t rac ks, and right pleural spac e w as demonst rat ed on subsequent endosc opic ret rograde c holangiopanc reat ography .

Chronic panc reat it is f requent ly result s in panc reat ic insuf f ic ienc y of bot h t he exoc rine and endoc rine f unc t ions. On t he c ont rary , if a pat ient rec ov ers f rom sev ere ac ut e nec rot izing panc reat it is, exoc rine f unc t ion is generally preserv ed alt hough it may diminish ov er t ime (13). Some pat ient s w it h no signif ic ant past medic al hist ory may init ially present in a st at e of panc reat ic insuf f ic ienc y w it hout c lear c ause; in t his populat ion, CT w as f ound t o be a key diagnost ic t ool in underst anding t he c ause of t he problem (310). Prev iously undiagnosed

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2332

15 - The Pancreas

panc reat ic c arc inoma, c lassic c hanges of c hronic panc reat it is, c onf irmat ion of c omplet e surgic al remov al, and ev idenc e of c omplet e idiopat hic at rophy w ere some of t he diagnost ic f indings desc ribed.

F igure 15- 97 Chronic panc reat it is w it h c hronic splenic v ein t hrombosis. A: A 5- mm port al v enous phase c omput ed t omography image demonst rat es at rophy of t he panc reat ic body and t ail w it h 1 c m c alc if ic at ion, possibly w it hin t he main panc reat ic duc t . Not e pat enc y of splenic v ein t o t he t ail/body junc t ion. Upst ream t o t his lev el, no normal splenic v ein c ould be seen c oursing t ow ards t he hilum. B: 5 c m c ephalad, ext ensiv e v aric es of t he post erior gast ric w all in t he gast roepiploic dist ribut ion are not ed due t o c hronic t hrombosis of t he splenic v ein near t he hilum.

In t heory , MRI may be bet t er suit ed t o det ec t t he f ibrosis of c hronic panc reat it is t han CT . In t he presenc e of f ibrosis, MRI w ill show a diminished signal int ensit y of t he gland on T 1 f at - suppressed images and diminished het erogeneous enhanc ement on immediat e post gadolinium- spoiled GRE images (303). In a report on 22 pat ient s, inc luding 13 w it h c hronic c alc if y ing panc reat it is and 9 w it h presumed ac ut e rec urrent panc reat it is, dif f erenc es bet w een t hese groups w ere observ ed on T 1 f at - suppressed (see F ig. 15- 31) and immediat e post gadolinium MRI images. All pat ient s w it h panc reat ic c alc if ic at ions had a diminished signal int ensit y of t he panc reat ic parenc hy ma on T 1 f at - suppressed and abnormally low perc ent c ont rast enhanc ement on post gadolinium images. In pat ient s w it h ac ut e rec urrent panc reat it is t he inv olv ed panc reas had signal int ensit y c omparable t o normal panc reat ic parenc hy ma. Bec ause f ibrosis may prec ede t he dev elopment of c alc if ic at ion, MRI may be c apable of det ec t ing t he onset of f ibrosis in c hronic panc reat it is earlier t han CT . How ev er, CT is muc h more sensit iv e t han MRI in det ec t ing

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2333

15 - The Pancreas c alc if ic at ions. T he diagnosis of c hronic panc reat it is on MRI is based on signal int ensit y and enhanc ement as w ell as morphologic c hanges of t he panc reat ic and bile duc t s depic t ed w it h MRCP (225).

F igure 15- 98 Prot einac eous pseudoc y st on magnet ic resonanc e imaging. A: A 8- mm axial T 2- w eight ed f at suppressed f ast spin ec ho image t hrough t he upper abdomen demonst rat es a smoot h, 4- c m f luid signal c ollec t ion superior t o t he panc reat ic body - t ail junc t ion, c onsist ent w it h a pseudoc y st . No int ernal debris is seen. B: A 6- mm T 1- w eight ed f at suppressed spin ec ho axial image similar lev el demonst rat es moderat ely high, homogeneous signal w it hin t he c ollec t ion c ompared t o t he low signal c erebrospinal f luid.

P.1085 In c ases in w hic h t he dif f erent ial diagnosis is bet w een panc reat ic c anc er and f oc al c hronic panc reat it is, MRI may be c apable of show ing dif f use low signal int ensit y of t he ent ire panc reas, inc luding t he area of f oc al enlargement on T 1 f at - suppressed and immediat e post gadolinium spoiled GRE images, lending support f or a diagnosis of c hronic panc reat it is. Johnson and Out w at er (155) f ound t hat bot h masslike c hronic panc reat it is and panc reat ic c arc inoma show ed more gradual progressiv e enhanc ement on dy namic MRI t han did normal panc reat ic parenc hy ma and w ere not dist inguishable on t he basis of degree and t ime of enhanc ement . Int erest ingly , nont umorous panc reas in pat ient s w it h c arc inoma show ed gradual enhanc ement t hat w as signif ic ant ly dif f erent f rom t hat of normal parenc hy ma. In a rec ent st udy c orrelat ing CT and MRI f eat ures in pat ient s w it h c hronic panc reat it is present ing as a f oc al mass, f our of sev en pat ient s had isoint ensit y of t he f oc al mass and t he remaining panc reat ic t issue on all MR sequenc es, inc luding dy namic parenc hy mal phase, port al v enous phase, and delay ed T 1- w eight ed images.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2334

15 - The Pancreas

Similar t o t he prev iously desc ribed f indings in pat ient s w hose CT demonst rat ed no dif f erenc e in at t enuat ion, pat hologic ev aluat ion of t he mass and t he remaining panc reat ic parenc hy ma rev ealed a similar degree of f ibrosis. When f oc al masses w ere det ec t able on MRI, pat hologic ev aluat ion rev ealed no f ibrosis in t he nonenlarged port ion of t he panc reas, and t y pic al c hanges of c hronic panc reat it is in t he masslike port ion. Small pseudoc y st s are w ell show n on gadolinium- enhanc ed T 1 f at - suppressed images and T 2- w eight ed sequenc es. High T 1 signal w it hin t he pseudoc y st may be due t o hemorrhage or prot einac eous mat erial (F ig. 15- 98). EUS may be helpf ul in ev aluat ing pat ient s w it h f oc al c hronic panc reat it is v ersus panc reat ic adenoc arc inoma, espec ially w hen endosc opic biopsy is used (331). Depic t ion of t he main panc reat ic duc t and side branc hes w it h MRCP has improv ed dramat ic ally w it h new er t ec hniques inc luding single shot RARE (half F ourier rapid ac quisit ion w it h relaxat ion enhanc ement ) or HAST E images (F ig. 15- 99) w it hout or w it h sec ret in st imulat ion. T he ev aluat ion of branc h duc t s is import ant and is essent ial f or diagnosing panc reat ic abnormalit ies suc h as c hronic panc reat it is P.1086 or IPMT (108). How ev er, t he segment s of duc t af f ec t ed by c hronic desmoplast ic panc reat it is may not be able t o dilat e (108,129). Hellerhof et al. (108) f ound t hat v isualizat ion of side branc hes w as signif ic ant ly improv ed in pat ient s w it h c hronic panc reat it is, but only if a dominant st ric t ure of t he main duc t w as not present . T his part ic ular st udy f ound an improv ement in t he sensit iv it y f or det ec t ion of c hronic panc reat it is f rom 77% t o 89%. In pat ient s w it h sev erely st enot ic port ions of t he main panc reat ic duc t , sec ret in st imulat ion c orrec t s ov erest imat ion of t he lengt h of st ric t ures on st andard MRCP, likely at t ribut able t o improv ed v isualizat ion of t he duc t dow nst ream f rom t he st ric t ure. Hellerhof f et al. report ed alt erat ion in t he primary diagnosis in 15 (16%) of 95 pat ient s af t er t he addit ion of dy namic sec ret in st imulat ion images t o rout ine MRCP; bet t er v isualizat ion of side branc hes and/or small duc t s allow ed t he aut hors t o det ec t addit ional c ases of c hronic panc reat it is and panc reas div isum. In addit ion t o improv ed v isualizat ion of t he panc reat ic duc t al sy st em during sec ret in st imulat ion MRCP, quant it at iv e assessment of panc reat ic exoc rine f unc t ion may be est imat ed noninv asiv ely (63,129,208).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2335

15 - The Pancreas

F igure 15- 99 Chronic panc reat it is magnet ic resonanc e c holangiopanc reat ography . A 5.0- c m t hic k axial slab half - F ourier ac quisit ion single- shot t urbo spin ec ho (HAST E) image demonst rat es moderat e dilat at ion of t he main panc reat ic duc t t hrough t he nec k, body , and t ail, up t o 8 mm, w it h sev eral abnormally dilat ed side branc hes in t he t ail region. No int raduc t al f illing def ec t s are ident if ied. Common bile duc t is not ed in t he panc reat ic head and is slight ly prominent in c aliber. T he pat t ern of duc t al dilat at ion is c onsist ent w it h moderat e c hronic panc reat it is.

Autoimmune Pancreatitis T he rec ent ly desc ribed phenomenon of aut oimmune panc reat it is (372), alt hough c onsidered a f orm of c hronic panc reat it is, is dif f erent in t hat st eroid t herapy is ef f ec t iv e in rev ersing bot h morphologic and f unc t ional panc reat ic abnormalit ies. Response t o st eroid t herapy is one of t he c rit eria f or diagnosing t his rare c ondit ion, also support ed by t he f ollow ing: elev at ion of serum gamma globulin and IgG, aut oant ibodies t o panc reat ic ant igens, impaired panc reat ic exoc rine f unc t ion, dif f use irregular narrow ing of t he main panc reat ic duc t on endosc opic ret rograde panc reat ogram, ly mphoplasmac y t ic prolif erat ion along w it h f ibrosis on biopsy , absenc e of ac ut e at t ac ks of panc reat it is, and oc c asional assoc iat ion w it h ot her aut oimmune disease. T he CT f eat ures of aut oimmune panc reat it is are dif f use or f oc al panc reat ic enlargement , dif f use delay ed enhanc ement on dy namic st udies, and a c apsule- like low - densit y rim surrounding t he panc reas (F ig. 15- 100) (144). In addit ion, t here is minimal or no peripanc reat ic inf lammat ion and no v asc ular enc asement (289). Rec ognit ion

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2336

15 - The Pancreas of t his disease is c linic ally import ant bec ause it is rev ersible w hen diagnosed and t reat ed c orrec t ly (144).

Pancreatic Changes in Cystic Fibrosis CF is a dy sf unc t ion of exoc rine glands c harac t erized by c hronic bronc hopulmonary inf ec t ions, malabsorpt ion sec ondary t o panc reat ic insuf f ic ienc y , and an inc reased sw eat sodium c onc ent rat ion. Complet e f at t y replac ement of t he panc reat ic parenc hy ma has been show n by bot h CT and US t o oc c ur in CF (F ig. 15- 101) (73,255). T he amount of f at t y replac ement c orrelat es w it h t he degree of panc reat ic exoc rine, but not endoc rine, dy sf unc t ion, and also c orrelat es direc t ly w it h t he degree of pulmonary dy sf unc t ion (322). MRI has been able t o demonst rat e similar c hanges in t he panc reas, and lac k of ionizing radiat ion may be of v alue in t his y oung pat ient populat ion. T hree pat t erns of panc reat ic abnormalit y hav e been desc ribed on MRI: lobulat ed enlarged panc reas w it h c omplet e f at t y replac ement , small at rophic panc reas w it h part ial f at t y replac ement , and dif f usely at rophic panc reas w it hout f at t y replac ement (338). F at t y replac ement is w ell show n on T 1- w eight ed images as high signal int ensit y t issue. T he f at t y nat ure of t he t issue may be c onf irmed w it h T 1 f at - suppressed images, by demonst rat ing suppression of t he signal f rom t he gland. A less c ommon manif est at ion of CF has been c omplet e replac ement of t he panc reas by mult iple mac rosc opic c y st s. T his f orm of panc reat ic c y st osis is c onsidered a proc ess in w hic h c omplet e c y st ic t ransf ormat ion of t he panc reas oc c urs, possibly relat ed t o duc t al prot ein hy perc onc ent rat ion, inspissat ion, and duc t al ec t asia (66,132). T he Sc hw ac hman- Diamond sy ndrome, w hic h oc c urs 100 t imes less c ommonly t han CF , is c onsidered sec ond only t o CF as a c ause of exoc rine panc reat ic insuf f ic ienc y in c hildren. T he absenc e of abnormal sw eat elec t roly t es and t he t endenc y t o improv ement dist inguishes t his disease f rom CF . On CT examinat ion in t his disease, t he panc reas c ommonly is t ot ally replac ed by f at . Lipomat osis of t he panc reas is t he t y pic al pat hologic f eat ure of t he sy ndrome (278). T he Johansen- Blizzard sy ndrome, w hic h c onsist s of c ongenit al aplasia of t he alae nasi, deaf ness, hy pot hy roidism, dw arf ism, absent permanent t eet h, and malabsorpt ion, present s w it h panc reat ic insuf f ic ienc y as a nearly unif orm f inding, and t he sev ere degree of malabsorpt ion is of t en f at al in inf anc y . If enzy me supplement s suc c essf ully c orrec t t he malabsorpt ion, t he af f ec t ed indiv iduals c an reac h adult hood. T ot al lac k of a normal panc reas and f at t y

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2337

15 - The Pancreas replac ement of panc reat ic bed is t he c harac t erist ic CT f inding. In c ont rast t o t he Sc hw ac hman- Diamond sy ndrome, in w hic h t he panc reat ic def ec t is rest ric t ed t o exoc rine dy sf unc t ion, diabet es mellit us w ill dev elop in pat ient s w it h t he Johansen- Blizzard sy ndrome (338).

Primary Hemochromatosis Primary hemoc hromat osis is a heredit ary disease in w hic h iron is deposit ed in t he parenc hy ma of v arious organs. Liv er, panc reas, and heart are primarily af f ec t ed. On MR images, t he iron deposit ion result s in loss of signal on T 2w eight ed sequenc es. Iron deposit ion is predominant ly in t he liv er. Deposit ion of iron in t he panc reas t ends t o oc c ur lat er, af t er liv er damage is irrev ersible (F ig. 15- 102) (312).

Pancreatic Trauma Bec ause of it s relat iv ely f ixed ext raperit oneal loc at ion just ant erior t o t he spine, t he panc reas oc c asionally is af f ec t ed in blunt upper abdominal t rauma. Panc reat ic injuries oc c ur in 2% t o 12% of pat ient s w it h blunt abdominal t rauma (321). Eit her blunt or penet rat ing abdominal t rauma may c ause panc reat ic duc t al disrupt ion, w it h subsequent esc ape of panc reat ic enzy mes and t he pot ent ial f or dev elopment P.1087 P.1088 of t he ent ire spec t rum of ac ut e panc reat it is. T he appearanc es of t raumat ic panc reat it is on CT are t he same as w it h a nont raumat ic c ause (336). One st udy of 10 pat ient s w it h surgic al or aut opsy prov ed panc reat ic injury af t er blunt abdominal t rauma w ho w ere all ev aluat ed w it h CT sc an show ed t he presenc e of f luid int erdigit at ing bet w een t he splenic v ein and t he panc reat ic parenc hy ma in nine pat ient s. T he aut hors c onc luded t hat t his w as a v ery helpf ul CT f inding f or t he diagnosis of t raumat ic panc reat ic injury (181). Complet e t ransec t ion of t he panc reas (F ig. 15- 103) c an be diagnosed by CT . T he t w o ends of t he t ransec t ed gland generally are separat ed by a v ariable quant it y of low - densit y f luid t hat w ill remain relat iv ely c onf ined t o t he ant erior pararenal spac e in t he immediat e post injury period (19,319). When lit t le f luid is present and t he f rac t ured segment s are minimally separat ed, t he hy poat t enuat ing f rac t ure line may be dif f ic ult t o det ec t . Ot her appearanc es of panc reat ic t rauma on w ell- perf ormed dy namic helic al CT (see T ables 15- 3 and 15- 4) inc lude dif f use gland enlargement w it h panc reat it is, peripanc reat ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2338

15 - The Pancreas hemat oma, and large peripanc reat ic f luid c ollec t ion (321) or in less sev ere injury , f oc al gland enlargement , c ont our irregularit y , or small int ra- or peripanc reat ic f luid ac c umulat ion (F ig. 15- 104) (177,247). Det erminat ion of duc t int egrit y in c ases of panc reat ic t rauma hist oric ally required endosc opic ret rograde panc reat ography . Oc c asionally , t he panc reas may hav e almost normal morphologic f eat ures on CT despit e t he presenc e of duc t disrupt ion (367). A rec ent st udy f ound t hat MR panc reat ography is an adequat e noninv asiv e t est f or t he det ec t ion of c omplet e t raumat ic disrupt ions of t he main panc reat ic duc t (321). MRI also depic t s f luid oc c upy ing t he spac e

bet w een f rac t ured port ions of t he gland. Int raoperat iv e injury of t he panc reas oc c asionally w ill be seen f ollow ing splenec t omy . T he diagnosis c an be est ablished by CT in t he early post operat iv e period (24,361).

F igure 15- 100 Aut oimmune panc reat it is in a 27- y ear- old w oman w it h aut oimmune hepat it is. A: Pre- int rav enous c ont rast 5- mm image demonst rat es global enlargement of t he panc reas. B: Port al v enous phase 5- mm c omput ed t omography image demonst rat es homogeneous enhanc ement w it h sev eral large v asc ular c hannels seen in t he grossly enlarged panc reas. C : Dif f use enlargement inc luded t he panc reat ic head, w hic h is smoot h in c ont our, normal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2339

15 - The Pancreas and homogeneous in at t enuat ion, and w it hout ev idenc e of duc t al dilat at ion. No low at t enuat ion peripheral c apsule is seen, as has been report ed in some

pat ient s w it h aut oimmune panc reat it is. Not e inc ident al jejunal int ussusc ept ion (* ).

F igure 15- 101 F at t y replac ement of t he panc reas in a 35- y ear- old man w it h c y st ic f ibrosis. A: Port al v enous phase 7- mm c omput ed t omography image at t he lev el of t he splenic v ein port al c onf luenc e demonst rat es slight ly het erogeneous f at replac ing t he superior head, nec k, and body of t he panc reas. B: 3 c m inf eriorly , f aint sof t t issue c apsule is seen surrounding t he f at replac ing t he panc reat ic head, normally loc at ed t o t he right of t he superior mesent eric v essels (ar r ow ).

Pancreatic Infections Opport unist ic inf ec t ions t hat hav e been report ed t o af f ec t t he panc reas in pat ient s w it h ac quired immunodef ic ienc y sy ndrome (AIDS) inc lude c y t omegalov irus, My c obac t er ium t uber c ulosis, and Pneum oc y st is c ar inii. Most of t en, panc reat ic inv olv ement by an inf ec t ious agent or neoplasm suc h as Kaposi sarc oma or ly mphoma is ov ershadow ed by sy mpt oms relat ed t o t he disease manif est ed elsew here in t he body (47,223). Ext rapulmonary Pneum oc y st is inf ec t ion of t he panc reas c an present on CT as punc t uat e c alc if ic at ions dispersed t hroughout t he gland. Wit h ot her inf ec t ions, t he panc reas may appear normal, or show t y pic al c hanges of ac ut e panc reat it is produc ed by ot her et iologies. Panc reat ic t uberc ulosis f eat ures on MRI hav e been rec ent ly desc ribed in a v ery small c ase series and inc lude f oc al or dif f use disease w it h hy point ensit y on f at - suppressed T 1 sequenc es and het erogeneous high signal on T 2- w eight ed images (75). Drugs suc h as

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2340

15 - The Pancreas pent amidine and t rimet hoprim- sulf amet hoxazole of t en used in AIDS pat ient s may produc e ac ut e panc reat it is as w ell (223). Peripanc reat ic ly mph node enlargement due t o my c obac t erial inf ec t ions or ly mphoma is f requent ly ev ident .

Postoperative Evaluation In pat ient s w ho hav e eit her part ial or t ot al panc reat ec t omy , most of t en f or neoplast ic disease, f requent ly it is dif f ic ult t o opac if y w it h oral c ont rast mat erial t he segment s of bow el used f or t he anast omosis t o t he biliary t ree or remaining segment of panc reas bec ause of t he direc t ion of f low in t hese Rouxen- Y loops. Administ rat ion of gluc agon prior t o CT imaging f ac ilit at es opac if ic at ion of t he af f erent jejunal loop w it h oral c ont rast mat erial, t hus helping t o def ine t he st ruc t ures in t he right upper quadrant and t o dist inguish t he unopac if ied loop of bow el f rom possible rec urrent t umor in t he region of t he surgic al bed f ormerly oc c upied by t he head of panc reas (130). In post operat iv e pat ient s, t he ly mph node–bearing region bet w een t he aort a and t he SMV and SMA, prev iously oc c upied by t he unc inat e proc ess of t he panc reas, is an import ant area t o ev aluat e f or t umor rec urrenc e (see F ig. 158). Bec ause radic al panc reat ec t omy usually leav es t his area f ree of t issue hav ing t he at t enuat ion v alue of eit her panc reat ic t issue or ly mph nodes, t umor rec urrenc e w ill be readily det ec t able by CT . Whet her t he Whipple is done in a st andard f ashion or w it h a py lorus- sparing t ec hnique, w here t he duodenal bulb apex is anast omosed end- t o- side t o t he Roux- en- Y jejunal loop, t he appearanc e on CT is quit e similar. Of t en af t er surgery , met allic c lips produc e beam- hardening art if ac t , making ev aluat ion of t he region ev en more c hallenging t han simply underst anding t he post operat iv e anat omy . T he ev aluat ion of panc reat ic f unc t ion in pat ient s af t er panc reat ic oduodenec t omy is import ant , bec ause many may bec ome diabet ic f ollow ing resec t ion. Sec ret in st imulat ion during MR panc reat ography not only helps in v isualizat ion of t he main panc reat ic duc t and panc reat ic ojejunal anast omosis in t hese pat ient s but also may show reduc ed jejunal f illing in pat ient s w it h diminished panc reat ic remnant f unc t ion (227). Af t er endosc opic , perc ut aneous, or surgic al drainage of f luid c ollec t ions assoc iat ed w it h ac ut e panc reat it is, CT may demonst rat e a v ariet y of abnormalit ies, inc luding adhesions (F ig. 15- 105), v aric es (F ig. 15- 106), and f ist ulae (F ig. 15- 107). Wit h t ransgast ric endosc opic t herapy , adhesions bet w een t he post erior gast ric w all and panc reat ic region are readily depic t ed,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2341

15 - The Pancreas part ic ularly w hen gast ric dist ension is good. A f oc al f luid c ollec t ion t rac king along t he c ourse of a prev iously pulled perc ut aneous c at het er or dissec t ing w it hin t he ret roperit oneum in a pat ient w it h hist ory of ac ut e nec rot izing

panc reat it is may indic at e disrupt ion of t he panc reat ic duc t (disc onnec t ed duc t sy ndrome); ident if ic at ion of t his f inding on CT may prompt f urt her int erv ent ions inc luding surgic al f ist ula repair or dist al panc reat ec t omy . Wit h surgery perf ormed f or c hronic panc reat it is, suc h as t he Puest ow proc edure (side- t o- side panc reat ic ojejunost omy ), t he post surgic al anat omy is of t en c omplex, and adequat e hist ory is nec essary t o properly int erpret t he sc an.

F igure 15- 102 Panc reas in primary hemoc hromat osis. T he panc reas (ar r ow ) is near signal v oid on 90- sec ond post gadolinium F LASH image c onsist ent w it h iron deposit ion in t he panc reas. T he liv er appears more normal in signal bec ause it is a t ransplant ed liv er.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2342

15 - The Pancreas

F igure 15- 103 T raumat ic panc reat ic lac erat ion in a 23- y ear- old man inv olv ed in a mot or v ehic le c ollision. Cont rast - enhanc ed c omput ed t omography t hrough t he lev el of t he port al c onf luenc e demonst rat es abrupt disc ont inuit y of panc reat ic enhanc ement at t he junc t ion of t he nec k and head, c onsist ent w it h panc reas lac erat ion. F luid is seen t rac king int o t he ant erior pararenal spac e bilat erally . Large st ellat e hepat ic lac erat ion w it h ac t iv e ext rav asat ion is also not ed. T he pat t ern of small bow el and adrenal enhanc ement is c onsist ent w it h shoc k (hy pot ension and hy pov olemia).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2343

15 - The Pancreas

F igure 15- 104 Panc reat ic injury w it hout lac erat ion in an 18- y ear- old male pedest rian st ruc k by mot or v ehic le, w it h hy pov olemia due t o sc alp lac erat ion hemorrhage. A: Cont rast - enhanc ed c omput ed t omography t hrough t he lev el of t he panc reat ic t ail demonst rat es normal lobularit y . No f oc al lac erat ions are not ed, but t here is f luid w it hin t he ret roperit oneal f at ant erior t o t he panc reat ic head. B: Image 2.5- mm c audal t o A rev eals f luid surrounding t he panc reat ic head. C : F luid f rom t he panc reat ic injury t rac ks inf eriorly int o t he mesent eric root .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2344

15 - The Pancreas

F igure 15- 105 Adhesions f ollow ing t ransgast ric endodrainage. A 7- mm port al v enous phase c omput ed t omography image demonst rat es t ent ing of t he post erior gast ric w all t ow ards t he panc reat ic t ail region w it h sev eral c ollat eral v essels. Similar f indings may be not ed af t er surgic al drainage.

P.1089 P.1090 CT may be t he f irst t est perf ormed af t er duodenal perf orat ion during ERCP, most of t en assoc iat ed w it h endosc opic sphinc t erot omy . Generally , a large amount of ret roperit oneal air (F ig. 15- 108), and somet imes int raperit oneal air are present , along w it h a v ariable amount of f luid in t he ant erior pararenal spac e, espec ially w hen t here is superimposed ERCP- induc ed panc reat it is (see F ig. 15- 69). In t he absenc e of perf orat ion, t he appearanc e of ERCP- induc ed panc reat it is is similar t o ac ut e panc reat it is produc ed by ot her et iologies.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2345

15 - The Pancreas F igure 15- 106 Venous c ollat eral f ormat ion af t er nec rosec t omy f or sev ere ac ut e panc reat it is in a 63- y ear- old man w it h hist ory of surgery 17 y ears

prev iously . A: Port al v enous phase c omput ed t omography image demonst rat es numerous c ollat erals in t he gast rohepat ic ligament and port a due t o port al c onf luenc e obst ruc t ion. Gast roepiploic c ollat erals are also present due t o splenic v ein oc c lusion. B: Nec rosec t omy bed ant erior t o splenic v ein and port al c onf luenc e demonst rat es absenc e of normal panc reat ic t issue and sc arring of t he ret roperit oneum. No main port al v ein or splenic v ein w ere ident if iable superior t o t his lev el.

F igure 15- 107 Lef t f lank f ist ula 26 mont hs af t er c ombined endosc opic and perc ut aneous drainage of panc reat ic nec rosis. A: T he pat ient present ed w it h f oc al redness and sw elling of t he lef t f lank. Cont rast - enhanc ed c omput ed t omography (CT ) image rev eals het erogeneous peripherally enhanc ing c omplex f luid c ollec t ion in t he lef t ant erior pararenal spac e, c onsist ent w it h f ist ula f ormat ion. B: Cont rast - enhanc ed CT image during ac ut e drainage of nec rot ic panc reat ic c ollec t ion 26 mont hs earlier show s bilat eral ant erior pararenal spac e perc ut aneous c at het ers in plac e. T he pat ient required dist al panc reat ec t omy f or disc onnec t ed duc t w it h residual f unc t ioning t issue in t he t ail (same pat ient as F igure 15- 6).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2346

15 - The Pancreas

F igure 15- 108 Endosc opic ret rograde c holangiopanc reat ography perf orat ion in a 39- y ear- old w oman undergoing sphinc t erot omy . Cont rast - enhanc ed c omput ed t omography demonst rat es air dissec t ing around t he right kidney , right border of t he panc reat ic head, and inf erior v ena c av a. T he pat ient rec ov ered unev ent f ully and w as disc harged t o home 2 day s lat er.

P.1091 P.1092

PANCREAS TRANSPLANTATION T he majorit y of panc reat ic t ransplant s are c ombined w it h renal t ransplant s in pat ient s w it h end st age renal disease due t o sev ere t y pe 1 diabet es mellit us. Higher panc reat ic graf t surv iv al rat es oc c ur in pat ient s w it h a c ombined proc edure, rat her t han panc reat ic t ransplant alone (241,260,318). T he surgic al t ec hniques f or panc reat ic t ransplant at ion c ont inue t o ev olv e. T he most c ommon met hod of panc reat ic t ransplant at ion plac es t he graf t in an int raperit oneal loc at ion of t he iliac f ossa opposit e t he renal t ransplant , w it h t he v asc ular pedic le anast omosed t o t he c ommon or ext ernal iliac v essels, and t he ac c ompany ing c uf f of duodenum anast omosed t o t he dome of t he urinary bladder (F ig. 15- 109). Henc e, on CT t he panc reas is inv ert ed w it h t he t ail c ephalad, and t he head adjac ent t o t he urinary bladder. Undesirable peripheral

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2347

15 - The Pancreas hy perinsulinemia and urinary c omplic at ions due t o disc harge of exoc rine

sec ret ions int o t he bladder hav e led t o t he dev elopment of a dif f erent surgic al met hod of panc reas t ransplant at ion. Wit h t he new er proc edure, t he port alent eric t ec hnique, t he duodenal c uf f is anast omosed side t o side w it h t he rec ipient jejunum, and t he v enous drainage of t he graf t is anast omosed t o t he rec ipient superior mesent eric v ein. On CT , t he head of t he panc reas is c ephalad, and t he graf t is loc at ed in a near- midline right paramedian posit ion. T he normal post operat iv e f indings of bot h t ransplant met hods are w ell depic t ed w it h high- resolut ion 3- D MRA (122). CT has not been part ic ularly v aluable in det ermining t he presenc e or absenc e of panc reas t ransplant rejec t ion (202), w hic h has been report ed in up t o 60% of c ases (178). Doppler sonography (241,366) and more rec ent ly c ont rast enhanc ed MRI (172) are bot h usef ul t ec hniques in ev aluat ing panc reas t ransplant s, w it h sonographic signs of rejec t ion inc luding dif f use allograf t enlargement , loss of marginal def init ion, resist iv e index great er t han 0.7 (366). Alt hough t hese signs are reasonably spec if ic , t hey hav e low sensit iv it y and perc ut aneous biopsy of t he panc reas t ransplant may be needed t o det ermine rejec t ion in ambiguous c ases. T he f inding of a diminished mean perc ent age of parenc hy mal enhanc ement indic at es rejec t ion on dy namic gadolinium- enhanc ed MRI and has a great er sensit iv it y f or ac ut e rejec t ion (96%) (178). In addit ion t o rejec t ion, t he graf t may be lost in t he immediat e perioperat iv e period, most c ommonly due t o v asc ular t hrombosis, report ed f rom 2% t o 19% (92), and less c ommonly due t o inf ec t ion, panc reat it is, bleeding, and anast omot ic leaks. CT is helpf ul in ev aluat ing post operat iv e c omplic at ions suc h as anast omot ic leaks (42), hemorrhage or ot her peripanc reat ic f luid c ollec t ions, or graf t panc reat it is, and w it h CT A t ec hniques has t he pot ent ial t o ident if y v asc ular t hrombosis. Vasc ular t hrombosis is det ec t able w it h Doppler US (102,241) and MRI (92,122). In part ic ular, CT may aid in dif f erent iat ing bet w een ac ut e rejec t ion and panc reat it is, w hic h may appear similar on US (241) and c an readily ident if y gas in pat ient s w it h emphy semat ous panc reat it is of t he graf t , due eit her t o inf ec t ion or major v asc ular t hrombosis. A rec ent ly desc ribed f easibilit y st udy ev aluat ing sec ret in- augment ed MR panc reat ography in t ransplant pat ient s show ed diminished exoc rine sec ret ion v olumes in pat ient s w it h panc reat ic allograf t dy sf unc t ion c ompared w it h pat ient s w it h normal f unc t ion. When c ombined w it h MR perf usion measurement t ec hniques, t his met hod may be of v alue in ev aluat ion of graf t f unc t ion (133).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2348

15 - The Pancreas

F igure 15- 109 Normal renal panc reas t ransplant in a 27- y ear- old man. Cont rast - enhanc ed c omput ed t omography t hrough t he pelv is demonst rat es renal allograf t in t he lef t iliac f ossa. Ant erior t o t he right psoas musc les and ext ernal iliac v essels lies t he inf erior port ion of t he panc reas t ransplant w it h a small duc t al st ruc t ure ev ident in t he head (ar r ow ). Duodenal c uf f (ar r ow ) lies immediat ely post erior and on low er images c ommunic at es w it h t he bladder dome.

CT is also usef ul in ident if y ing post t ransplant at ion ly mphoprolif erat iv e disorder (PT LD), w hic h in one st udy (213) oc c urred in 2.4% of 337 panc reas- kidney t ransplant rec ipient s at a mean of 137 day s af t er t ransplant at ion. On CT , dif f use enlargement of t he allograf t w as t he most c ommon f inding, making dif f erent iat ion f rom panc reat it is or rejec t ion dif f ic ult , but in ot her c ases f oc al mass in t he allograf t , or f oc al int ra- and ext raallograf t masses suggest ed t he diagnosis of PT LD (213). How ev er, t he c onc erns f or renal dy sf unc t ion in t his part ic ular pat ient populat ion are great , and it is likely t hat t he role of CT as a f irst - line imaging met hod in t he ev aluat ion of panc reas t ransplant s w ill be limit ed. CT remains t he w orkhorse of panc reat ic imaging. Adv anc es in v olumet ric abdominal imaging hold t he promise of improv ed ac c urac y f or CT ev aluat ion of c ommon panc reat ic pat hology suc h as ac ut e and c hronic panc reat it is, t rauma, and panc reat ic c arc inoma. T ec hnology c hanges t oday and in t he f ut ure w ill require c aref ul at t ent ion t o c ont rast t iming and administ rat ion t ec hniques on a disease- spec if ic basis. Gadolinium- enhanc ed MRI is usef ul w hen iodinat ed c ont rast f or CT is c ont raindic at ed due t o allergy or impaired renal f unc t ion and f or problem solv ing w hen st andard imaging leav es c linic ally import ant quest ions

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2349

15 - The Pancreas

unansw ered. MRCP is an ideal met hod t o noninv asiv ely st udy panc reat ic duc t al st ruc t ures, and is usef ul as an adjunc t t o CT . T he emerging role of EUS in t he ev aluat ion of P.1093 panc reat ic disorders has y et t o be def ined; t he operat or dependenc y and limit ed av ailabilit y of t his modalit y relegat e t he use of EUS t o a problemsolv ing imaging t ec hnique. Likew ise, t he role of PET imaging f or panc reat ic disorders w ill likely inc rease as t he need f or c ombined phy siologic and anat omic inf ormat ion bec omes more c rit ic al.

REFERENCES 1. Adkisson KW, Baron T H, Morgan DE. Panc reat ic f luid c ollec t ions: diagnosis and endosc opic management . Sem in Gast r oint est Dis 1998;9:61–72. 2. Adsay NV, Longnec ker DS, Klimst ra DS. Panc reat ic t umors w it h c y st ic dilat at ion of t he duc t s: int raduc t al papillary muc inous neoplasms and int raduc t al onc oc y t ic papillary neoplasms. Sem in Diagn Pat hol 2000;17:16–30. 3. Adsay NV, Pierson C, Sarkar F , et al. Colloid (muc inous nonc y st ic ) c arc inoma of t he panc reas. Am J Sur g Pat hol 2001;25:26–42. 4. Agarw al N, Pit c humoni CS. Assessment of sev erit y in ac ut e panc reat it is. Am J Gast r oent er ol 1991;86:1385–1391. 5. Ahmad NA, Koc hman ML, Lew is JD, Ginsberg GG. Can EUS alone dif f erent iat e bet w een malignant and benign c y st ic lesions of t he panc reas? Am J Gast r oent er ol 2001;96:3295–300. 6. Ahmed A, Chan KF , Song IS. Annular panc reas. J Com put Assist T om ogr 1982;6:409–411. 7. Akerst rom G, Hellman P, Hessman O, Osmak L. Surgic al t reat ment of endoc rine panc reat ic t umours. Neur oendoc r inology 2004;80:62–66. 8. Americ an Canc er Soc iet y . Canc er f ac t s and f igur es 2004: y ear sur v eillanc e r esear c h f r om t he Am er ic an Canc er Soc iet y . Bet hesda MD: Americ an Canc er Soc iet y , 2004. 9. Ammori JB, Collet t i LM, Zalupski MM, et al. Surgic al resec t ion f ollow ing radiat ion t herapy w it h c onc urrent gemc it abine in pat ient s w it h prev iously unresec t able adenoc arc inoma of t he panc reas. J Gast r oint est Sur g 2003;7:766–772. 10. Anderson MA, Sc heiman JM. Nonmuc inous c y st ic panc reat ic neoplasms. Gast r oint est Endosc Clin Nor t h Am 2002;12:769–79.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2350

15 - The Pancreas 11. Anderson MA, Carpent er S, T hompson NW, et al. Endosc opic ult rasound is highly ac c urat e and direc t s management in pat ient s w it h neuroendoc rine t umors of t he panc reas. Am J Gast r oent er ol 2000;95:2271–2277. 12. Angeli E, Vent urini M, Vanzulli A, et al. Color Doppler imaging in t he assessment of v asc ular inv olv ement by panc reat ic c arc inoma. AJR Am J Roent genol 1997;168:193–197. 13. Angelini G, Pederzoli P, Caliari S, et al. Long- t erm out c ome of ac ut e nec rohemorrhagic panc reat it is: a 4- y ear f ollow - up. Digest ion 1984;30:131–137. 14. Aranha GV, Prinz RA, F reeark RJ, Greenlee HB. T he spec t rum of biliary t rac t obst ruc t ion f rom c hronic panc reat it is. Ar c h Sur g 1984;119:595–600. 15. Ardengh JC, Rosenbaum P, Ganc AJ, et al. Role of EUS in t he preoperat iv e loc alizat ion of insulinomas c ompared w it h spiral CT . Gast r oint est Endosc 2000;51:552–555. 16. Aspest rand F , Kolmannskog F . CT c ompared t o angiography f or st aging of t umors of t he panc reat ic head. Ac t a Radiol 1992;33: 556–560. 17. Aspest rand F , Kolmannskog F , Jac obsen M. CT , MR imaging and angiography in panc reat ic apudomas. Ac t a Radiol 1993;34: 468–473. 18. Baek SY , Sheaf or DH, Keogan MT , et al. T w o- dimensional mult iplanar and t hree dimensional v olume- rendered v asc ular CT in panc reat ic c arc inoma:

int erobserv er agreement and c omparison w it h st andard helic al t ec hniques. AJR Am J Roent genol 2001;176: 1467–1473. 19. Baker LP, Wagner EJ, Brot man S, Whit ley NO. T ransec t ion of t he panc reas. J Com put Assist T om ogr 1982;6:411–412. 20. Baker ME. Panc reat ic adenoc arc inoma: are t here pat hognomonic c hanges in t he f at surrounding t he superior mesent eric art ery ? Radiology 1991;180:613–614. 21. Balt hazar EJ. Ac ut e panc reat it is: assessment of sev erit y w it h c linic al and CT ev aluat ion. Radiology 2002;223:603–613. 22. Balt hazar EJ, Chako AC. Comput ed t omography of panc reat ic masses. Am J Gast r oent er ol 1990;85:343–349. 23. Balt hazar EJ, F reeny PC, v anSonnenberg E. Imaging and int erv ent ion in ac ut e panc reat it is. Radiology 1994;193:297–306. 24. Balt hazar EJ, Megibow A, Rot hberg M, Lef leur RS. CT ev aluat ion of panc reat ic injury f ollow ing splenec t omy . Gast r oint est Radiol 1985;10:139–144.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2351

15 - The Pancreas

25. Balt hazar EJ, Ranson JHC, Naidic h DP, et al. Ac ut e panc reat it is: prognost ic v alue of CT . Radiology 1985;156:767–772. 26. Balt hazar EJ, Robinson DL, Megibow AJ, Ranson JHC. Ac ut e panc reat it is: v alue of CT in est ablishing prognosis. Radiology 1990;174:331–336. 27. Balt hazar EJ, Subramany am BR, Lef leur RS, Barone CM. Solid and papillary epit helial neoplasm of t he panc reas: radiographic , CT , sonographic , and angiographic f eat ures. Radiology 1984;150: 39–40. 28. Banks PA. Ac ut e panc reat it is: medic al and surgic al management . Am J Gast r oent er ol 1994;89:S78–S85. 29. Banks PA. Cent ral c av it ary nec rosis. Panc r eas 1993;8:141–145. 30. Banks PA. Prac t ic e guidelines in ac ut e panc reat it is. Am J Gast r oent er ol 1997;92:377–386. 31. Barish MA, Sot o JA. MR c holangiopanc reat ography : t ec hniques and c linic al applic at ions. AJR Am J Roent genol 1997;169: 1295–1303. 32. Baron RL, St anley RJ, Lee JKT , et al. Comput ed t omographic f eat ures of biliary obst ruc t ion. AJR Am J Roent genol 1983;140: 1173–1178. 33. Baron T H, Morgan DE. Current c onc ept s: ac ut e nec rot izing panc reat it is. N Engl J Med 1999;340:1412–1417. 34. Baron T H, T haggard WG, Morgan DE, St anley RJ. Endosc opic t herapy of organized panc reat ic nec rosis. Gast r oent er ology 1996; 111: 755–764. 35. Bassi C, Proc ac c i C, Zamboni G, et al. Int raduc t al papillary muc inous t umors of t he panc reas: w here are w e now ? Int J Panc r eat ol 2000;27:181–193. 36. Beger HG, Kraut zberger W, Bit t ner R, et al. Result s of surgic al t reat ment of nec rot izing panc reat it is. Wor ld J Sur g 1985;9: 972–979. 37. Beger HG, Rau B, Gansauge F , et al. T reat ment of panc reat ic c anc er: c hallenge of t he f ac t s. Wor ld J Sur g 2003;D:1075–1084. 38. Beger H, Rau B, May er J, et al. Nat ural c ourse of ac ut e panc reat it is. Wor ld J Sur g 1997;21:130–135. 39. Berk JE. T he Management of ac ut e panc reat it is: a c rit ic al assessment as Dr. Boc kus w ould hav e w ished. Am J Gast r oent er ol 1995;90:696–703. 40. Berland LL, Law son T L, F oley WD, et al. Comput ed t omography of t he normal and abnormal panc reat ic duc t : c orrelat ion w it h panc reat ic duc t ography . Radiology 1981;141:715–724. 41. Bernades P, Baet z A, Lev y P, et al. Splenic and port al v enous obst ruc t ion in c hronic panc reat it is. A prospec t iv e longit udinal st udy of a medic al- surgic al series of 266 pat ient s. Dig Dis Sc i 1992;37:340–346.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2352

15 - The Pancreas

42. Bisc hof T P, T hoeni RF , Melzer JS. Diagnosis of duodenal leaks f rom kidney panc reas t ransplant s in pat ient s w it h duodenov esic al anast omoses: v alue of CT c y st ography . AJR Am J Roent genol 1995;165:349–354. 43. Bluemke DA, Cameron JL, Hruban RH, et al. Pot ent ially resec t able panc reat ic adenoc arc inoma: spiral CT assessment w it h surgic al and pat hologic c orrelat ion. Radiology 1995;197:381–385. 44. Boden G. Gluc agonomas and insulinomas. Gast r oent er ol Clin Nor t h Am 1989;18:831–845. 45. Bok EJ, Cho KJ, Williams DM, et al. Venous inv olv ement in islet c ell t umors of t he panc reas. AJR Am J Roent genol 1984;142: 319–322. 46. Boland GW, O'Malley ME, Saez M, et al. Panc reat ic - phase v ersus port al v ein- phase helic al CT of t he panc reas: opt imal t emporal w indow f or ev aluat ion of panc reat ic adenoc arc inoma. AJR Am J Roent genol 1999;172:605–608. 47. Bonac ini M. Panc reat ic inv olv ement in human immunodef ic ienc y v irus inf ec t ion. J Clin Gast r oent er ol 1991;13:58–64. 48. Bonaldi VM, Bret PM, At ri M, Reinhold C. Helic al CT of t he panc reas: a c omparison of c ine display and f ilm- based v iew ing. AJR Am J Roent genol 1998;170:373–376. 49. Bonaldi VM, Bret PM, At ri M, et al. A c omparison of t w o injec t ion prot oc ols using helic al and dy namic ac quisit ions in CT examinat ions of t he panc reas. AJR Am J Roent genol 1996;167: 49–55. P.1094 50. Boy le P, Hsieh CC, Maisonneuv e P, et al. Epidemiology of panc reas c anc er (1988). Int J Panc r eat ol 1989;5:327–346. 51. Bradley EL. A c linic ally based c lassif ic at ion sy st em f or ac ut e panc reat it is. Ar c h Sur g 1993;128:586–590. 52. Bradley EL, Allen K. A prospec t iv e longit udinal st udy of observ at ion v ersus surgic al int erv ent ion in t he management of nec rot izing panc reat it is. Am J Sur g 1991;161:19–25. 53. Brand R. T he diagnosis of panc reat ic c anc er. Canc er J 2001;7: 287–297. 54. Brandt KR, Charboneau JW, St ephens DH, et al. CT and US guided biopsy of t he panc reas. Radiology 1993;187:99–104. 55. Breat nac h ES, Han SY , Rahat zad MT , St anley RJ. CT ev aluat ion of gluc agonomas. J Com put Assist T om ogr 1985;9:25–29. 56. Bret PM, Nic olet V, Labadie M. Perc ut aneous f ine- needle aspirat ion biopsy of t he panc reas. Diagn Cy t opat hol 1986;2:221–222.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2353

15 - The Pancreas 57. Bret PM, Reinhold C, T aourel P, et al. Panc reas div isum: ev aluat ion w it h MR c holangiopanc reat ography . Radiology 1996;100: 99–103.

58. Broughan T A, Leslie JD, Sot o JM, Hermann RE. Panc reat ic islet c ell t umors. Sur ger y 1986;99:671–678. 59. Brugge WR, Lew androw ski K, Lee- Lew androw ski E, et al. Diagnosis of panc reat ic c y st ic neoplasms: a report of t he c ooperat iv e panc reat ic c y st st udy . Gast r oent er ology 2004;126:1330–1336. 60. Buet ow PC, Buc k JL, Pant ongrag- Brow n L, et al. Solid and papillary epit helial neoplasm of t he panc reas: imaging- pat hologic c orrelat ion in 56 c ases. Radiology 1996;199:707–711. 61. Beut ow PC, Rao P, T hompson LD. Muc inous c y st ic neoplasms of t he panc reas. Radiogr aphic s 1998;18:433–449. 62. Cant isani V, Mort ele KJ, Lev y A, et al. MR imaging f eat ures of solid pseudopapillary t umor of t he panc reas in adult and pediat ric pat ient s. AJR Am J Roent genol 2003;181:395–401. 63. Cappeliez O, Delhay e M, Dev iere J, et al. Chronic panc reat it is: ev aluat ion of panc reat ic exoc rine f unc t ion w it h MR panc reat ography af t er sec ret in st imulat ion. Radiology 2000;215:358–364. 64. Chong N, F reeny PC, Sc hmiedl UP. Panc reat ic art erial anat omy : depic t ion w it h dual- phase helic al CT . Radiology 1998;208: 537–542. 65. Chu QD, Khushalani N, Jav le MM, et al. Should adjuv ant t herapy remain t he st andard of c are f or pat ient s w it h resec t ed adenoc arc inoma of t he panc reas? Ann Sur g Onc ol. 2003;10:539–45. 66. Churc hill RJ, Cunningham DG, Henkin RE, Rey nes CJ. Mac rosc opic c y st s of t he panc reas in c y st ic f ibrosis demonst rat ed by mult iple radiologic al modalit ies. JAMA 1981;245:72–74. 67. Clark LR, Jaf f e MH, Choy ke PL, et al. Panc reat ic imaging. Radiol Clin Nor t h Am 1985;23:489- 501. 68. Cohen- Sc ali F , Vilgrin V, Branc at elli G, et al. Disc riminat ion of uniloc ular mac roc y st ic serous c y st adenoma f rom panc reat ic pseudoc y st and muc inous c y st adenoma w it h CT : init ial observ at ions. Radiology 2003;228:727–733. 69. Compt on C. Serous c y st ic t umors of t he panc reas. Sem in Diagn Pat hol 2000;17:43–55. 70. Cot t on PB. Congenit al anomaly of panc reas div isum as c ause of obst ruc t iv e pain and panc reat it is. Gut 1980;21:105–114. 71. Creut zf eldt W. Endoc rine t umors of t he panc reas. In: Volk BW, Arquilla ER, eds. T he diabet ic panc r eas, 2nd ed. New Y ork: Plenum, 1985:543–586.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2354

15 - The Pancreas 72. Curry CA, Eng J, Hort on KM, et al. CT of primary c y st ic panc reat ic neoplasms; c an CT be used f or pat ient t riage and t reat ment ? AJR Am J Roent genol 2000;175:99–103. 73. Daneman A, Gaskin K, Mart in DJ, Cut z E. Panc reat ic c hanges in c y st ic f ibrosis: CT and sonographic appearanc es. AJR Am J Roent genol 1983;141:653–655. 74. Dav idian M, Koo A. Panc reat obronc hial f ist ula diagnosed by c ombined ERP and CT . AJR Am J Roent genol 1996;166:53–54. 75. DeBac ker AI, Mort ele KJ, Bomans P, et al. T uberc ulosis of t he panc reas: MRI f eat ures. AJR Am J Roent genol 2005;184:50–54.

76. Delbeke D, Rose DM, Chapman WC, et al. Opt imal int erpret at ion of F DG PET in t he diagnosis, st aging, and management of panc reat ic c arc inoma. J Nuc l Med 1999;40:1784–1791. 77. Del Masc hio A, Vanzulli A, Sironi S, et al. Panc reat ic c anc er v ersus c hronic panc reat it is: diagnosis w it h CA 19- 9 assessment , US, CT and CT - guided f ine needle biopsy . Radiology 1991;178:178: 95–99. 78. Delv alle J, Y amada T . Sec ret ory t umors of t he panc reas. In: Sleisenger MH, F ordt ran JS, eds. Gast r oint est inal disease: pat hophy siology , diagnosis, m anagem ent , 4t h ed. Philadelphia: Saunders, 1990:1884–1900. 79. Demeure MJ, Dof f ek KM, Komorow ski RA, et al. Molec ular met ast ases in st age 1 panc reat ic c anc er: improv ed surv iv al w it h adjuv ant c hemoradiat ion. Sur ger y 1998;124:663–669. 80. Demos T C, Posniak HV, Harmat h C, et al. Cy st ic lesions of t he panc reas. AJR Am J Roent genol 2002;179:1375–1388. 81. Derv enis C, Johnson CD, Bassi C, et al. Diagnosis, objec t iv e assessment of sev erit y , and management of ac ut e panc reat it is. Int J Panc r eat ol 1999;25:195–210. 82. Di Maggio EM, Solc ia M, Dore R, et al. Int rapanc reat ic lipoma: f irst c ase diagnosed w it h CT . AJR Am J Roent genol 1996;167: 56–57. 83. di Sant 'Agnese PA. Ac inar c ell c arc inoma of t he panc reas. Ult r st r uc t Pat hol 1991;15:573–577. 84. Diehl SJ, Lehmann KJ, Gaa J, et al. MR imaging of panc reat ic lesions: c omparison of manganese- DPDP and gadolinium c helat e. Inv est Radiol 1999;34:589–595. 85. Diehl SJ, Lehmann KJ, Sadic k M, et al. Panc reat ic c anc er: v alue of dualphase helic al CT in assessing resec t abilit y . Radiology 1998; 206:373–378.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2355

15 - The Pancreas 86. Doppman JL, Shaw ker T H, Miller DL. Loc alizat ion of islet c ell t umors. Gast r oent er ol Clin Nor t h Am 1989;18:793–804. 87. Dunn GD, Gibson RN. T he lef t - sided panc reas. Radiology 1986;159:713–714. 88. Ec henique AM, Sleeman D, Y rizarry J, et al. Perc ut aneous c at het er-

direc t ed debridement of inf ec t ed panc reat ic nec rosis: result s in 20 pat ient s. J Vasc Int er v Radiol 1998;9:565–571. 89. Ec khauser F E, Cheung PS, Vinik AI, et al. Nonf unc t ioning malignant neuroendoc rine t umors of t he panc reas. Sur ger y 1986;100: 978–988. 90. Eelkema EA, St ephens DH, Ward EM, Sheedy PF II. CT f eat ures of nonf unc t ioning islet c ell c arc inoma. AJR Am J Roent genol 1984;143:943–948. 91. El- Ray es BF , Zalupski MM, Shields AF , et al. Phase II st udy of gemc it abine, c isplat in, and inf usional f luorourac il in adv anc ed panc reat ic c anc er. J Clin Onc ol 2003;21:2920–2925. 92. Eubank WB, Sc hmiedl UP, Lev y AE, Marsh CL. Venous t hrombosis and oc c lusion af t er panc reas t ransplant at ion: ev aluat ion w it h breat h- hold gadolinium- enhanc ed t hree- dimensional MR imaging. AJR Am J Roent genol 2000;175:381–385. 93. F eket e PS, Nunez C, Pit lik DA. F ine- needle aspirat ion biopsy of t he panc reas: a st udy of 61 c ases. Diagn Cy t opat hol 1986;2: 301–306. 94. F ernandez- del Cast illo C, Warshaw AL. Cy st ic neoplasms of t he panc reas. Panc r eat ology 2001;1:641–647. 95. F idler JL, F let c her JG, Reading CC, et al. Preoperat iv e det ec t ion of panc reat ic insulinomas on mult iphasic helic al CT . AJR Am J Roent genol 2003,181:775–780. 96. F idler Jl, Johnson CD. Imaging of neuroendoc rine t umors of t he panc reas. Int J Gast r oint est Canc er 2001;30:73–85. 97. F ishman EK. CT angiography : c linic al applic at ions in t he abdomen. Radiogr aphic s 2001;21:S3–S16. 98. F oit zik T , Bassi D, Sc hmidt J, et al. Int rav enous c ont rast medium ac c ent uat es t he sev erit y of ac ut e nec rot izing panc reat it is in t he rat . Gast r oent er ology 1994;106:207–214. 99. F oley WD. Mult idet ec t or CT : abdominal v isc eral imaging. Radiogr aphic s 2002;22:701–719. 100. F ont ham ET , Correa P. Epidemiology of panc reat ic c anc er. Sur g Clin Nor t h Am 1989;69:551–567.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2356

15 - The Pancreas 101. F ot oohi M, D'Agost ino HB, Wollman B, et al. Persist ent panc reat oc ut aneous f ist ula af t er perc ut aneous drainage of panc reat ic f luid c ollec t ions: role of c ause and sev erit y of panc reat it is. Radiology 1999;213:573–578. 102. F oshager MC, Hedlund LJ, T roppman C, et al. Venous t hrombosis of panc reat ic t ransplant s: diagnosis by duplex sonography . AJR Am J Roent genol 1997;169:1269–1273. 103. F reeny PC, Haupt mann E, Alt haus SJ, et al. Perc ut aneous CT - guided c at het er drainage of inf ec t ed ac ut e nec rot izing panc reat it is: t ec hniques and result s. AJR Am J Roent genol 1998;170: 969–975. P.1095 104. F reeny PC, T rav erso LW, Ry an JA. Diagnosis and st aging of panc reat ic adenoc arc inoma w it h dy namic c omput ed t omography . Am J Sur g 1993;165:600–606. 105. F riedman AC, Lic ht enst ein JE, F ishman EK, et al. Solid and papillary epit helial neoplasm of t he panc reas. Radiology 1985;154: 333–337. 106. F ruc ht H, Doppman JL, Nort on JA, et al. Gast rinomas: c omparison of MR imaging w it h CT , angiography , and US. Radiology 1989;171:713–717. 107. F ukukura Y , F ujiy oshi F , Sasaki M, et al. Int raduc t al papillary muc inous

t umors of t he panc reas: t hin- sec t ion helic al CT f indings. AJR Am J Roent genol 2000;174:441–447. 108. F ukukura Y , F ujiy oshi F , Sasaki M, Nakajo M. Panc reat ic duc t : morphologic ev aluat ion w it h MR c holangiopanc reat ography af t er sec ret in st imulat ion. Radiology 2002;222: 674–680. 109. F urukaw a H, Iw at a R, Moriy ama N, Kosuge T . Selec t iv e int ra- art erial c ont rast - enhanc ed CT of panc reat ic oduodenal t umors: early c linic al experienc e in ev aluat ing blood supply and det ec t abilit y . AJR Am J Roent genol 2000;175:91–97. 110. Gabat a T , Masui S, Kadoy a M, et al. Small panc reat ic adenoc arc inomas: ef f ic ac y of MR imaging w it h f at suppression and gadolinium enhanc ement . Radiology 1994; 193:683–688. 111. Ghode SC, T ot h J, Krest in GP, Debat in JF . Dy namic c ont rast - enhanc ed F MPSPGR of t he panc reas: impac t on diagnost ic perf ormanc e. AJR Am J Roent genol 1997;168:689–696. 112. Gines A, Vasquez- Sequeiros E, Soria MT , et al. Usef ulness of EUS- guided f ine needle aspirat ion (EUS- F NA) in t he diagnosis of f unc t ioning neuroendoc rine t umors. Gast r oint est Endosc 2002; 56:291–296.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2357

15 - The Pancreas 113. Gold EB, Cameron JL. Chronic panc reat it is and panc reat ic c anc er. N Engl J Med 1993;328:1485–1486. 114. Graf O, Boland GW, Warshaw AL, et al. Art erial v ersus port al v enous phase helic al CT f or rev ealing panc reat ic adenoc arc inoma: c onspic uit y of t umor and c rit ic al v asc ular anat omy . AJR Am J Roent genol 1997;169:119–123. 115. Gress F G, Haw es RH, Sav ides T J, et al. Role of EUS in t he preoperat iv e st aging of panc reat ic c anc er: a large single- c ent er experienc e. Gast r oint est Endosc 1999;50:786–791. 116. Gress F , Mic hael H, Gelrud D, et al. EUS- guided f ine- needle aspirat ion of t he panc reas: ev aluat ion of panc reat it is as a c omplic at ion. Gast r oint est Endosc 2002;56:864–867. 117. Grizzle WE. Use of silv er st aining met hods t o ident if y c ells of t he dispersed neuroendoc rine sy st em. J Hist ot ec hnol 1996;19: 225–234. 118. Grogan JR, Saeian K, T ay lor AJ, et al. Making sense of muc in- produc ing panc reat ic t umors. AJR Am J Roent genol 2001;176: 921–929. 119. Guiband L, Bret PM, Reinhold C, et al. Diagnosis of c holedoc holit hiasis: v alue of MR Cholangiopanc reat ography . AJR Am J Roent genol 1994;163:847–850. 120. Günt her RW, Klose KJ, Rüc kert K, et al. Loc alizat ion of small islet - c ell t umors. Preoperat iv e and int raoperat iv e ult rasound, c omput ed t omography , art eriography , digit al subt rac t ion angiography , and panc reat ic v enous sampling. Gast r oint est Radiol 1985;10:145–152. 121. Günt her RW, Klose KJ, Rüc kert K, et al. Islet - c ell t umors: det ec t ion of small lesions w it h c omput ed t omography and ult rasound. Radiology 1983;148:485–488. 122. Hagspiel KD, Nandalur K, Burkholder B, et al. Cont rast - enhanc ed MR angiography af t er panc reas t ransplant at ion: normal appearanc e and v asc ular c omplic at ions. AJR Am J Roent genol 2005; 184:465–473. 123. Hajdu ED, Kamari- Subaiy a S, Phillips G. Ult rasonic ally guided perc ut aneous aspirat ion biopsy of t he panc reas. Sem in Diagn Pat hol 1986;3:166–175. 124. Hall- Craggs, MA, Lees WR. F ine needle aspirat ion biopsy : panc reat ic and biliary t umors. AJR Am J Roent genol 1986;147: 399–403. 125. Handric h SJ, Hough DM, F let c her JG, Sarr MG. T he nat ural hist ory of t he

inc ident ally disc ov ered simple panc reat ic c y st : long- t erm f ollow up and c linic al implic at ions. AJR Am J Roent genol 2005;184:20–23.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2358

15 - The Pancreas 126. Hann LE, Conlon KC, Doughert y EC, et al. Laparosc opic sonography of peripanc reat ic t umors: preliminary experienc e. AJR Am J Roent genol 1997;169:1257–1262. 127. Hanninen EL, Amt hauer H, Host en N, et al. Prospec t iv e ev aluat ion of

panc reat ic t umors: ac c urac y of MR imaging w it h MR Cholangiopanc reat ography and MR angiography . Radiology 2002; 224:34–41. 128. Hariri M, Sliv ka A, Carr- Loc ke DL, Banks PA. Pseudoc y st drainage predisposes t o inf ec t ion w hen panc reat ic nec rosis is unrec ognized. Am J Gast r oent er ol 1994;89:1781–1784. 129. Hellerhof K, Hekmberger H, Rosc h T , et al. Dy namic MR panc reat ography af t er sec ret in administ rat ion: image qualit y and diagnost ic ac c urac y . AJR Am J Roent genol 2002;179;121–129. 130. Heiken JP, Balf e DM, Pic us D, Sc harp DW. Radic al panc reat ec t omy : post operat iv e ev aluat ion by CT . Radiology 1984;153: 211–215. 131. Heit z PU, Kasper M, Polak JM, Kloppel G. Panc reat ic endoc rine t umors. Hum Pat hol 1982;13:263–271. 132. Hernanz- Sc hulman M, T eele RL, Perez- At ay de A, et al. Panc reat ic c y st osis in c y st ic f ibrosis. Radiology 1986;158:629–631. 133. Hev erhagen JT , Wagner HJ, Ebel H, et al. Panc reat ic t ransplant s: noninv asiv e ev aluat ion w it h sec ret in- augment ed MR panc reat ography and MR perf usion measurement s—preliminary result s. Radiology 2004;233:273–280. 134. Ho CL, Dehdasht i F , Grif f et h LK, et al. F DG- PET ev aluat ion of indet erminat e panc reat ic masses. J Com put Assist T om ogr 1996;20: 363–369. 135. Hollerbac h S, Klamann A, T opalidis T , Sc hmiegel WH. Endosc opic ult rasonography (EUS) and f ine- needle aspirat ion (F NA) c y t ology f or diagnosis of c hronic panc reat it is. Endosc opy 2001;33: 824–831. 136. Hort on KM, F ishman EK. Mult idet ec t or CT angiography of panc reat ic c arc inoma: part 1, ev aluat ion of art erial inv olv ement . AJR Am J Roent genol 2002;178:827–831. 137. Hort on KM, F ishman EK. Mult idet ec t or CT angiography of panc reat ic c arc inoma: part 2, ev aluat ion of art erial inv olv ement . AJR Am J Roent genol 2002;178:833–836. 138. Ibukuro K, T sukiy ama T , Mori K, Inoue Y . Peripanc reat ic v eins on t hinsec t ion (3mm) helic al CT . AJR Am J Roent genol 1996;167:1003–1008.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2359

15 - The Pancreas 139. Ic hikaw a T , Haradome H, Hac hiy a J, et al. Panc reat ic duc t al adenoc arc inoma: preoperat iv e assessment w it h helic al CT v ersus dy namic MR imaging. Radiology 1997;202:655–662. 140. Ic hikaw a T , Pet erson MS, F ederle MP, et al. Islet c ell t umor of t he panc reas: biphasic CT v ersus MR Imaging in t umor det ec t ion. Radiology 2000;216:163–171.

141. Imbriac o M, Megibow AJ, Camera L, et al. Dual phase v ersus single phase helic al CT t o det ec t and assess resec t abilit y of panc reat ic c arc inoma. AJR Am J Roent genol 2002;178:1473–1479. 142. Inamot o K, Ishikaw a Y , It oh N. CT demonst rat ion of annular panc reas: c ase report . Gast r oint est Radiol 1983;8:143–144. 143. Inoue Y , Nakamura H. Aplasia or hy poplasia of t he panc reat ic unc inat e proc ess: c omparison in pat ient s w it h and pat ient s w it hout int est inal nonrot at ion. Radiology 1997;205:531–533. 144. Irie H, Honda H, Baba S, et al. Aut oimmune panc reat it is: CT and MR c harac t erist ic s. AJR Am J Roent genol 1998;179:1323–1327. 145. Irie H, Honda H, Aibe H, et al. MR c holangiopanc reat ographic dif f erent iat ion of benign and malignant int raduc t al muc in- produc ing t umors of t he panc reas. AJR Am J Roent genol 2000;174:1403–1408. 146. Isenmann R, Buc hler M, Uhl W, et al. Panc reat ic nec rosis: an early f inding in sev ere ac ut e panc reat it is. Panc r eas 1993;8: 358–361. 147. It ai Y , Ohhashi K, F urui S, et al. Mic roc y st ic adenoma of t he panc reas: spec t rum of c omput ed t omographic f indings. J Com put Assist T om ogr 1988;12:797–803. 148. It ai Y , Ohhashi K, Nagai H, et al. “ Duc t ec t at ic ” muc inous c y st adenoma and c y st adenoc arc inoma of t he panc reas. Radiology 1986;161:697–700. 149. It oh Y , Hada T , T erano A, et al. Panc reat it is in t he annulus of annular panc reas demonst rat ed by t he c ombined use of c omput ed t omography and endosc opic ret rograde c holangiopanc reat ography . Am J Gast r oent er ol 1989;84:961–964. P.1096 150. Jaksic T , Y aman M, T horner P, et al. A 20- y ear rev iew of pediat ric panc reat ic t umors. J Pediat r Sur g 1992;27:1315–1317. 151. Jensen RT , Gardner JD. Gast rinoma. In: Go VW, DiMagno EP, Gardner JD, et al, eds. T he panc r eas: biology , pat hobiology and disease, 2nd ed. New Y ork: Rav en Press, 1993:931–978.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2360

15 - The Pancreas 152. Jensen RT , Nort on JA. Endoc rine neoplasms of t he panc reas. In: Y amada T , ed. T ext book of gast r oent er ology , 2nd ed., v ol. 2. Philadelphia: JB Lippinc ot t , 1995:2131–2160. 153. Jhala D, Eloubeidi M, Chieng DC, et al. F ine needle aspirat ion biopsy of

t he islet c ell t umor of t he panc reas: a c omparison bet w een c omput erized axial t omography and endosc opic ult rasound- guided f ine needle aspirat ion biopsy . Ann Diag Pat hol 2002;6:106–112. 154. Johnson CD. T iming of int erv ent ion in ac ut e panc reat it is. Post gr ad Med J 1993;69:509–515. 155. Johnson PT , Out w at er EK. Panc reat ic c arc inoma v ersus c hronic panc reat it is: dy namic MR imaging. Radiology 1999;212: 213–218. 156. Johnson CD, St ephens DH, Charboneau JW, et al. Cy st ic panc reat ic t umors: CT and sonographic assessment . AJR Am J Roent genol 1988;151:1133–1138. 157. Kahl S, Glasbrenner B, Zimmermann S, Malf ert heiner P. Endosc opic ult rasound in panc reat ic diseases. Dig Dis 2002;20(2): 120–126. 158. Kalbhen CL, Y et t er EM, Olson MC, et al. Assessing t he resec t abilit y of panc reat ic c arc inoma: t he v alue of reint erpret ing abdominal CT perf ormed at ot her inst it ut ions. AJR Am J Roent genol 1998;171:1571–1576. 159. Kalra MK, Maher MM, Boland GW, et al. Correlat ion of posit ron emission t omography and CT in ev aluat ing panc reat ic t umors: t ec hnic al and c linic al implic at ions. AJR Am J Roent genol 2003;181: 387–393. 160. Kaneko K, Honda H, Hay ashi T , et al. Helic al CT ev aluat ion of art erial inv asion in panc reat ic t umors: c omparison w it h angiography . Abdom Im aging 1997;22:204–207. 161. Kanemat su M, Shirat ori Y , Hoshi H, et al. Panc reas and peripanc reat ic v essels: ef f ec t of gadolinium enhanc ement at dy namic gradient - rec alled- ec ho MR imaging. Radiology 2000;215: 95–102. 162. Karasaw a E, Goldberg HI, Moss AA, et al. CT panc reat ogram in c arc inoma of t he panc reas and c hronic panc reat it is. Radiology 1983;148:489–493. 163. Kat t w inkel J, Lapey A, di Sant 'Agnese PA, et al. Heredit ary panc reat it is: t hree new kindreds and a c rit ic al rev iew of t he lit erat ure. Pediat r ic s 1973;51:55–69. 164. Kelekis NL, Smelka RC, Siegelman ES. MRI of panc reat ic met ast ases f rom renal c anc er. J Com put Assist T om ogr 1996;20: 249–253.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2361

15 - The Pancreas 165. Keogan MT , Mc Dermot t VG, Paulson EK, et al. Panc reat ic malignanc y : ef f ec t of dual- phase helic al CT in t umor det ec t ion and v asc ular opac if ic at ion. Radiology 1997;205:513–518. 166. Keogan MT , T y ler D, Clark L, et al. Diagnosis of panc reat ic c arc inoma: role of F DG PET . AJR Am J Roent genol 1998;171: 1565–1570. 167. Khurana B, Mort ele KJ, Glic kman J, et al. Mac roc y st ic serous adenoma of t he panc reas: radiologic - pat hologic c orrelat ion. AJR Am J Roent genol 2003;181:119–123. 168. Kim HJ, Czisc hke K, Brennan MF , Conlon KC. Does neoadjuv ant

c hemoradiat ion dow nst age loc ally adv anc ed panc reat ic c anc er? J Gast r oint est Sur g 2002;5:763–769. 169. Kim JH, Kim MJ, Chung JJ, et al. Dif f erent ial diagnosis of periampullary c arc inomas at MR imaging. Radiogr aphic s 2002;22: 1335–1352. 170. Kim T , Murakami T , T akahashi S, et al. Panc reat ic CT imaging: ef f ec t s of dif f erent injec t ion rat es and doses of c ont rast media. Radiology 1999;212:219–225. 171. Kim T , Murakami T , T akamua M, et al. Panc reat ic mass due t o c hronic panc reat it is: c orrelat ion of CT and MR imaging f eat ures w it h pat hologic f indings. AJR Am J Roent genol 2001;177:367–371. 172. King AD, Ko GT C, Y eung VT F , et al. Dual phase spiral CT in t he det ec t ion of small insulinomas of t he panc reas. Br J Radiol 1998;71:20–23. 173. Kingsnort h AN, Gallow ay SW, Lew is- Jones H, et al. Papillary c y st ic neoplasm of t he panc reas: present at ion and nat ural hist ory in t w o c ases. Gut 1992;33:421–423. 174. Kiv isaari L, Somer K, St andert skjold- Nordenst am CG, et al. A new met hod f or t he diagnosis of ac ut e hemorrhagic - nec rot izing panc reat it is using c ont rast enhanc ed CT . Gast r oint est Radiol 1984;9:27–30. 175. Kloppel G, Heit z PU. Panc reat ic endoc rine t umors. Pat hol Res Pr ac t 1988;183:155–168. 176. Koit o K, Namieno T , Ic himura T , et al. Muc in- produc ing panc reat ic t umors: c omparison of MR c holangiopanc reat ography w it h endosc opic ret rograde c holangiopanc reat ography . Radiology 1998; 208:231–237. 177. Koit o K, Namieno T , Nagakaw a T , et al. Inf lammat ory panc reat ic masses; dif f erent iat ion f rom duc t al c arc inomas w it h c ont rast - enhanc ed sonography using c arbon dioxide mic robubbles. AJR Am J Roent genol 1997;169:1263–1267.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2362

15 - The Pancreas 178. Krebs T L, Daly B, Wong JJ, et al. Ac ut e panc reat ic t ransplant rejec t ion: ev aluat ion w it h dy namic c ont rast - enhanc ed MR imaging c ompared w it h hist opat hologic analy sis. Radiology 1999;210: 437–442. 179. Lal A, Bourt sos EP, DeF rias DV, et al. Mic roc y st ic adenoma of t he panc reas: c linic al, radiologic , and c y t ologic f eat ures. Canc er 2004;102:288–294. 180. Lammer J, Herlinger H, Zalaudek G, Hof ler H. Pseudot umorous panc reat it is. Gast r oint est Radiol 1985;10:59–67.

181. Lane MJ, Mindelzun RE, Sandhu JS, et al. CT diagnosis of blunt panc reat ic t rauma: import anc e of det ec t ing f luid bet w een t he panc reas and t he splenic v ein. AJR Am J Roent genol 1994;163: 833–835. 182. Larv in M Mc Mahon MJ. APACHE II sc ore f or assessment and monit oring of ac ut e panc reat it is. Lanc et 1989;ii;201–204. 183. Lec esne R, T aourel P, Bret PM, et al. Ac ut e panc reat it is: int erobserv er agreement and c orrelat ion of CT and MR c holangiopanc reat ography w it h out c ome. Radiology 1999;211:727–735. 184. Legmann P, Vignaux O, Dousset B, et al. Panc reat ic t umors: c omparison of dual- phase helic al CT and endosc opic sonography . AJR Am J Roent genol 1998;170:1315–1322. 185. Lehman GA. Endosc opic management of panc reat ic pseudoc y st s c ont inues t o ev olv e. Gast r oint est Endosc 1995;42: 273–275. 186. Lepant o L, Arzoumanian Y , Gianf elic e D, et al. Helic al CT w it h CT angiography in assessing periampullary neoplasms: ident if ic at ion of v asc ular inv asion. Radiology 2002;222:347–352. 187. Lesniak RJ, Hohenw alt er MD, T ay lor AJ. Spec t rum of c auses of panc reat ic c alc if ic at ions. AJR Am J Roent genol 2002;178:79–86. 188. Lev y MJ, Clain JE. Ev aluat ion and management of c y st ic panc reat ic t umors: emphasis on t he role of EUS F NA. Clin Gast r oent er ol Hepat ol 2004;8:639–653. 189. Lev y P, Mat hurin P, Roqueplo A, et al. A mult idimensional c ase- c ont rol st udy of diet ary , alc ohol, and t obac c o habit s in alc oholic men w it h c hronic panc reat it is. Panc r eas 1995;10:231–238. 190. Ley endec ker JR, Elsay es KM, Grat z BI, Brow n JJ. MR c holangiopanc reat ography : spec t rum of panc reat ic duc t abnormalit ies. AJR Am J Roent genol 2002;179:1465–1471.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2363

15 - The Pancreas

191. Ligneau B, Lombard- Bohas C, Part ensky C, et al. Cy st ic endoc rine t umors of t he panc reas: c linic al, radiologic and hist opat hologic f eat ures in 13 c ases. Am J Sur g Pat hol 2001;25: 752–760. 192. Lim JH, Lee G, Oh Y L. Radiologic spec t rum of int raduc t al papillary muc inous t umors of t he panc reas. Radiogr aphic s 2001: 21- 232–340. 193. Lin A, F eller ER. Panc reat ic c arc inoma as a c ause of unexplained panc reat it is: report of t en c ases. Ann Int er n Med 1990;113: 166–167. 194. Low enf els AB, Maisonneuv e P, Cav allini G, et al. Panc reat it is and t he risk of panc reat ic c anc er. Int ernat ional Panc reat it is St udy Group. N Engl J Med 1993;328:1433–1437. 195. Lu DSK, Reber HA, Krasny RM, et al. Loc al st aging of panc reat ic c anc er: c rit eria f or unresec t abilit y of major v essels as rev ealed by panc reat ic - phase t hin- sec t ion helic al CT . AJR Am J Roent genol 1997;168:1439–1443. 196. Lu DSK, Vedant ham S, Krasny RM, et al. T w o phase helic al CT f or panc reat ic t umors: panc reat ic v ersus hepat ic phase enhanc ement of t umor, panc reas and v asc ular st ruc t ures. Radiology 1996;199:697–701. P.1097 197. Luet mer PH, St ephens DH, Ward EM. Chronic panc reat it is: reassessment w it h c urrent CT . Radiology 1989;171:353–357. 198. Lumkin B, Anderson MW, Ablin DS, Mc Gahan JP. CT , MRI, and c olor Doppler ult rasound c orrelat ion of panc reat oblast oma: a c ase report . Pediat r Radiol 1993;23:61–62. 199. Lundst et C, Daw iskiba S. Serous and muc inous c y st adenomas/ c y st adenoc arc inomas of t he panc reas. Abdom Im aging 2000;25: 201–206. 200. Mac ari M, Lazarus D, Israel G, Megibow A. Duodenal div ert ic ula mimic king c y st ic neoplasm of t he panc reas: CT and MR imaging f indings in sev en pat ient s. AJR Am J Roent genol 2003;180: 195–199. 201. Maier W. Early objec t iv e diagnosis and st aging of ac ut e panc reat it is by c ont rast enhanc ed CT . In: Beger H, Buc hler M, eds. Ac ut e panc r eat it is. Berlin: Springer- Verlag, 1987:132–140. 202. Maile CW, Crass JR, F ric k MP, et al. CT of panc reas t ransplant at ion. Inv est Radiol 1985;20:609–612. 203. Mainw aring R, Kern J, Sc henk WG, Rudolf LE. Dif f erent iat ing panc reat ic pseudoc y st and panc reat it is nec rosis using c omput erized t omography . Ann Sur g 1989;209:562–568. 204. Malf ert heiner P, Dominguez- Munoz JE. Prognost ic f ac t ors in ac ut e panc reat it is. Int J Panc r eat ol 1993;14:1–8.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2364

15 - The Pancreas 205. Manf redi R, Cost amagna G, Brizi MG, et al. Sev ere c hronic panc reat it is v ersus suspec t ed panc reat ic disease: dy namic MR c holangiopanc reat ography af t er sec ret in st imulat ion. Radiology 2000;215:358–364.

206. Marc os HB, Libut t i SK, Alexander HR, et al. Neuroendoc rine t umors of t he panc reas in v on Hippel- Lindau disease: spec t rum of appearanc es at CT and MR imaging w it h hist opat hologic c orrelat ion. Radiology 2002;225:751–758. 207. Mat on PN, Miller DL, Doppman JL, et al. Role of selec t iv e angiography in t he management of pat ient s w it h Zollinger- Ellison sy ndrome. Gast r oent er ology 1987;92:913–918. 208. Mat os C, Met ens T , Dev iere J, et al. Panc reat ic duc t : morphologic and f unc t ional ev aluat ion w it h dy namic MR panc reat ography af t er sec ret in st imulat ion. Radiology 1997;203:435–441. 209. Mc Cart hy S, Pellegrini CA, Moss AA, Way LW. Pleuropanc reat ic f ist ula: endosc opic ret rograde c holangiopanc reat ography and c omput ed t omography . AJR Am J Roent genol 1984;142: 1151–1154. 210. Mc F arland EG, Kauf man JA, Saini S, et al. Preoperat iv e st aging of c anc er of t he panc reas: v alue of MR angiography v ersus c onv ent ional angiography in det ec t ing port al v enous inv asion. AJR Am J Roent genol 1996;166:37–43. 211. Mc Menamin DA, Gat es LK. A ret rospec t iv e analy sis of t he ef f ec t of c ont rast enhanc ed CT on t he out c ome of ac ut e panc reat it is. Am J Gast r oent er ol 1996;91:1384–1387. 212. Mc Nult y NJ, F ranc is IR, Plat t JF , et al. Mult i- det ec t or row helic al CT of t he panc reas: ef f ec t of c ont rast - enhanc ed mult iphasic imaging on enhanc ement of t he panc reas, peripanc reat ic v asc ulat ure, and panc reat ic adenoc arc inoma. Radiology 2001;220: 97–102. 213. Meador T L, Krebs T L, Wong JJ, et al. Imaging f eat ures of post t ransplant at ion ly mphoprolif erat iv e disorder in panc reas t ransplant rec ipient s. AJR Am J Roent genol 2000;174:121–124. 214. Megibow AJ, Zhou XH, Rot t erdam H, et al. Panc reat ic adenoc arc inoma: CT v ersus MR imaging in t he ev aluat ion of resec t abilit y - report of t he Radiology Diagnost ic Onc ology Group. Radiology 1995;195:327–332. 215. Meining A, Dit t ler HJ, Wolf A, et al. Y ou get w hat y ou expec t ? A c rit ic al appraisal of imaging met hodology in endosonographic c anc er st aging. Gut 2002;50:599–603. 216. Mendez G Jr, Isikof f MB. Signif ic anc e of int rapanc reat ic gas demonst rat ed by CT : a rev iew of nine c ases. AJR Am J Roent genol 1979;132:59–62.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2365

15 - The Pancreas 217. Mergo P, Helmberger T , Buet ow PC, et al. Panc reat ic neoplasms: MR imaging and pat hologic c orrelat ion. Radiogr aphic s 1997;17: 281–301. 218. Merkle EM, Bender G, Brambs HJ. Imaging f indings in panc reat ic ly mphoma: dif f erent ial aspec t s. AJR Am J Roent genol 2000; 174:671–675. 219. Met zgar RS, Asc h HL. Ant igens of human panc reat ic adenoc arc inomas: t heir role in diagnosis and t herapy . Panc r eas 1988; 3:352.

220. Mey ers MA, F eldberg MA, Oliphant M. Grey T urner's sign and Cullen's sign in ac ut e panc reat it is. Gast r oint est Radiol 1989;14: 31–37. 221. Midw int er MJ, Bev eridge CJ, Wilsdon JB, et al. Correlat ion bet w een spiral c omput ed t omography , endosc opic ult rasonography and f indings at operat ion in panc reat ic and ampullary t umours. Br J Sur g 1999;86:189–193. 222. Miller DL. Islet c ell t umors of t he panc reas: diagnosis and loc alizat ion. In: F reeny PC, St ev enson GW eds. Mar gulis and Bur henne's alim ent ar y t r ac t r adiology , v ol. 2. St . Louis: Mosby - Y ear Book, 1994:1167–1196. 223. Miller F H, Gore RM, Nemc ek AA, F it zgeral SW. Panc reat ic obiliary manif est at ions of AIDS. AJR Am J Roent genol 1996;166: 1269–1274. 224. Miller F H, Keppe AL, Dalal K, et al. MRI of panc reat it is and it s c omplic at ions: part I, ac ut e panc reat it is. AJR Am J Roent genol 2004;183:1645–1652. 225. Miller F H, Keppe AL, Wadhw a A, et al. MRI of panc reat it is and it s c omplic at ions: part II, c hronic panc reat it is. AJR Am J Roent genol 2004;183:1645–1652. 226. Mit c hell DG, Cruv ella M, Esc helman DJ, et al. MRI of panc reat ic gast rinomas. J Com put Assist T om ogr 1992;16:583–585. 227. Monill J, Pernas J, Clav ero J, et al. Panc reat ic duc t af t er panc reat oduodenec t omy : Morphologic and f unc t ional ev aluat ion w it h sec ret inst imulat ed MR panc reat ography . AJR Am J Roent genol 2004;183:1267–1274. 228. Morant R, Bruc kner HW. Complet e remission of ref rac t ory small c ell c arc inoma of t he panc reas w it h c isplat in and et oposide. Canc er 1989;64:2007–2009. 229. Morgan DE, Baron T H, Sit h JK, et al. Panc reat ic f luid c ollec t ion prior t o int erv ent ion: ev aluat ion w it h MR imaging c ompared w it h CT and US. Radiology 1997;203:773–778. 230. Morgan DE, Logan K, Baron T B, et al. Panc reas div isum: implic at ions f or diagnost ic and t herapeut ic panc reat ography . AJR Am J Roent genol 1999;173:193–198.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2366

15 - The Pancreas

231. Mori H, Mc Grat h F P, Malone DE, St ev enson GW. T he gast roc olic t runk and it s t ribut aries: CT ev aluat ion. Radiology 1992;182: 871–877. 232. Mort ele KJ, Weisner W, Int riere L, et al. A modif ied CT Sev erit y Index f or ev aluat ing ac ut e panc reat it is: improv ed c orrelat ion w it h pat ient out c ome. AJR Am J Roent genol 2004;183: 1261–1265. 233. Mozell E, St enzel P, Wolt ering EA, et al. F unc t ional endoc rine t umors of t he panc reas: c linic al present at ion, diagnosis, and t reat ment . Cur r Pr obl Sur g 1990;27:301–386. 234. Mulholland MW, Moossa AR, Liddle RA. Panc reas: anat omy and st ruc t ural anomalies. In: Y amada T , ed. T ext book of gast r oent er ology , 2nd ed., v ol. 2. Philadelphia: JB Lippinc ot t , 1995: 2051–2064. 235. Murr MM, Sarr MG, Oishi AJ, v an Heerden JA. Panc reat ic c anc er. Ca Canc er J Clin 1994;44:304–318. 236. Nat ional Canc er Inst it ut e. Annual c anc er st at ist ic s rev iew : 1975- 1988. Bet hesda, MD: US Depart ment of Healt h and Human Serv ic es;1991. NIH Public at ion 91–1789. 237. Nef f CC, Simeone JF , Wit t enberg J, et al. Inf lammat ory panc reat ic masses: problems in dif f erent iat ing f oc al panc reat it is f rom c arc inoma. Radiology 1984;150:35–38. 238. Neopt olemos JP, Dunn JA, St oc ken DD, et al. European St udy Group f or Panc reat ic Canc er. Adjuv ant c hemoradiot herapy and c hemot herapy in resec t able panc reat ic c anc er: a randomised c ont rolled t rial. Lanc et 2001;358:1576–1585. 239. Neopt olemos JP, St oc ken DD, Dunn JA, et al. European St udy Group f or Panc reat ic Canc er. Inf luenc e of resec t ion margins on surv iv al f or pat ient s w it h panc reat ic c anc er t reat ed by adjuv ant c hemoradiat ion and/or c hemot herapy in t he ESPAC- 1 randomized c ont rolled t rial. Ann Sur g 2001;234:758–768. 240. Ng CS, Loy er EM, Iy er RB, et al. Met ast ases t o t he panc reas f rom renal c ell c arc inoma: f indings on t hree- phase c ont rast - enhanc ed helic al CT . AJR Am J Roent genol 1999;172:1555–1559. 241. Nikolaides P, Amin RS, Hw ang C, et al. Role of sonography on panc reat ic t ransplant at ion. Radiogr aphic s 2003;23:939–949. 242. Nino- Murc ia M, Jef f rey RB, Beaulieu, et al. Mult idet ec t or CT of t he panc reas and bile duc t sy st em: v alue of c urv ed planar ref ormat ions. AJR Am J Roent genol 2001;176:689–693. P.1098

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2367

15 - The Pancreas 243. Nishiharu T , Y amashit a Y , Abe Y , et al Loc al ext ension of panc reat ic c arc inoma: assessment w it h t hin sec t ion helic al CT v ersus w it h breat h- hold f ast MR imaging- ROC analy sis. Radiology 1999; 212:445–452. 244. Nort on JA, Cromac k DT , Shaw ker T H, et al. Int raoperat iv e ult rasonographic loc alizat ion of islet c ell t umors: a prospec t iv e c omparison t o palpat ion. Ann Sur g 1988;207:160–168. 245. Nort on JA, Lev in B, Jensen RT . Canc er of t he endoc rine sy st em. In: DeVit a VT Jr, Hellman S, Rosenberg SA, eds. Canc er : pr inc iples and pr ac t ic e of onc ology , v ol 2, 4t h ed. Philadelphia: JB Lippinc ot t , 1993:1333–1435. 246. Nort on JA, Shaw ker T H, Doppman JL, et al. Loc alizat ion and surgic al t reat ment of oc c ult insulinomas. Ann Sur ger y 1990;212: 615–620. 247. Nov elline R, Rhea JT , Bell T . Helic al CT of abdominal t rauma. Radiol Clin Nor t h Am 1999;37:591–612. 248. Nozaw a Y , Abe M, Sakuma H, et al. A c ase of panc reat ic onc oc y t ic t umor. Ac t a Pat hol Jpn 1990;40:367–370. 249. Ohhashi K, Murakami F , Maruy ama K, et al. F our c ases of “ muc inproduc ing” c anc er of t he panc reas. Pr og Dig Endosc 1982; 20:348–351.

250. Oht omo K, F urui S, Onoue M, et al. Solid and papillary epit helial neoplasm of t he panc reas: MR imaging and pat hologic c orrelat ion. Radiology 1992;184:567–570. 251. Onay a H, It ai Y , Niit su M, Chiba T , et al. Duc t ec t ac t ic muc inous c y st ic neoplasms of t he panc reas: ev aluat ion w it h MR Cholangiopanc reat ography . AJR Am J Roent genol 1998;171:171–177. 252. Oshikaw a O, T anaka S, Ioka T , et al. Dy namic sonography of panc reat ic t umors; c omparison w it h dy namic CT . AJR Am J Roent genol 2002;178:1133–1137. 253. Palazzo, L, Roseau G, Gay et B, et al. Endosc opic ult rasonography in t he diagnosis and st aging of panc reat ic adenoc arc inoma. Endosc opy 1993;25:143–150. 254. Pasanen PA, Eskelinen M, Part anen K, et al. A prospec t iv e st udy of t he v alue of imaging, serum markers and t heir c ombinat ion in t he diagnosis of panc reat ic c arc inoma in sy mpt omat ic pat ient s. Ant ic anc er Res 1992;12:2309–2314. 255. Pat el S, Bellon EM, Haaga J. F at replac ement of t he exoc rine panc reas. AJR Am J Roent genol 1980;135:843–845.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2368

15 - The Pancreas

256. Paulson EK, Vit ellas KM, Keogan MT , et al. Ac ut e panc reat it is c omplic at ed by gland nec rosis: spec t rum of f indings on c ont rast - enhanc ed CT . AJR Am J Roent genol 1999;172:609–613. 257. Phan GQ, Y eo CJ, Hruban RH, Lillemore KD, et al. Surgic al experienc e w it h panc reat ic and peripanc reat ic neuroendoc rine t umors: rev iew of 125 pat ient s. J Gast r oinest Sur g 1998;2: 472–482. 258. Pic ozzi VJ, Kozarek RA, T rav erso LW. Int erf eron- based adjuv ant c hemoradiat ion t herapy af t er panc reat ic oduodenec t omy f or panc reat ic adenoc arc inoma. Am J Sur g 2003;185:476–480. 259. Pisegna JR, Doppman JL, Nort on JA, et al. Prospec t iv e c omparat iv e st udy of abilit y of MR imaging and ot her imaging modalit ies t o loc alize t umors in pat ient s w it h Zollinger- Ellison sy ndrome. Dig Dis Sc i 1993;38:1318–1328. 260. Pozniak MA, Propec k PA, Kelc z F , Sollinger H. Imaging of panc reas t ransplant s. Radiol Clin Nor t h Am 1995;33:581–594. 261. Pray er L, Sc huraw it zki H, Mallek R, Most bec k G. CT in panc reat ic inv olv ement of non- Hodgkin ly mphoma. Ac t a Radiol 1992; 33:123–127. 262. Pric e J, Coc kram CS, Mc Guire LJ, et al. Upt ake of 99mT c - met hy lene diphosphonat e by panc reat ic insulinoma. AJR Am J Roent genol 1987;149:69–70. 263. Proc ac c i C, Graziani R, Bic ego E, et al. Int raduc t al muc in- produc ing t umors of t he panc reas: imaging f indings. Radiology 1996;198:249–257. 264. Proc ac c i C, Biast iut t i C, Carbognin G, et al. Charac t erizat ion of c y st ic t umors of t he panc reas: CT ac c urac y . J Com put Assist T om ogr 1999;23:906–912. 265. Prokesh RW, Chow LC, Beaulieu C, et al. Isoat t enuat ing panc reat ic adenoc arc inoma at mult i- det ec t or row CT : sec ondary signs. Radiology 2002;224:746–768. 266. Prokesh RW, Chow , LC, Beaulieu CF , et al. Loc al st aging of panc reat ic c arc inoma w it h mult i- det ec t or row CT : use of c urv ed planar ref ormat ionsinit ial experienc e. Radiology 2002;225:759–765. 267. Ranson JHC, Rif kind KM, Roses DF , et al. Objec t iv e early ident if ic at ion of sev ere ac ut e panc reat it is. Am J Gast r oent er ol 1974;61: 443–451. 268. Ranson JH. Ac ut e panc reat it is—w here are w e? Sur g Clin Nor t h Am 1981;61:55–70. 269. Rapt opoulos V, Prassopoulos P, Chut t ani R, et al. Mult iplanar CT panc reat ography and dist al c holangiography w it h minimum int ensit y projec t ions. Radiology 1998;207:317–324.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2369

15 - The Pancreas

270. Rapt opoulos V, St eer ML, Sheiman RG, et al. T he use of helic al CT and CT angiography t o predic t v asc ular inv olv ement f rom panc reat ic c anc er: c orrelat ion w it h f indings at surgery . AJR Am J Roent genol 1997;168:971–977. 271. Rat t ner DW, Legermat e DA, Lee MJ, et al. Early surgic al debridement of sy mpt omat ic panc reat ic nec rosis is benef ic ial irrespec t iv e of inf ec t ion. Am J Sur g 1992;163:105–110. 272. Raut CP, Grau AM, St aerkel GA, et al. Diagnost ic ac c urac y of endosc opic ult rasound- guided f ine- needle aspirat ion in pat ient s w it h presumed panc reat ic c anc er. J Gast r oint est Sur g 2003;7(1): 118–128. 273. Rav it c h MM, Woods AC. Annular panc reas. Ann Sur g 1950;132: 1116–1127. 274. Rieber A, T omc zak R, Nussle K, et al. MRI w it h mangof odipir t risodium in t he det ec t ion of panc reat ic t umours: c omparison w it h helic al CT . Br J Radiol 2000;73:1165–1169. 275. Reiman T H, Balf e DM, Wey man PJ. Suprapanc reat ic biliary obst ruc t ion: CT ev aluat ion. Radiology 1987;163:49–56. 276. Reinhold C, Bret PM. Current st at us of MR c holangiopanc reat ography . AJR Am J Roent genol 1996;166:1285–1290. 277. Rit t s R Jr, Klug T , Jac obsen D, et al. Mult iple t umor marker t est s enhanc e sensit iv it y of panc reat ic c arc inoma det ec t ion. Canc er Det ec t Pr ev 1984;7:459. 278. Robberec ht E, Nac ht egaele P, Van Rat t inghe R, et al. Panc reat ic lipomat osis in t he Shw ac hman- Diamond sy ndrome: ident if ic at ion by sonography and CT sc an. Pediat r Radiol 1985;15:348–349. 279. Roc he CJ, Hughes ML, Garv ey CJ, et al. CT and pat hologic al assessment of prospec t iv e nodal st aging inpat ient s w it h duc t al adenoc arc inoma of t he head of t he panc reas. AJR Am J Roent genol 2003;180:475–480. 280. Roc key DC, Cello JP. Panc reat ic opleural f ist ula. Report of 7 pat ient s and rev iew of t he lit erat ure. Medic ine 1990;69:332–344. 281. Rohrmann CA, Suraw ic z CM, Hut c hinson D, et al. T he diagnosis of heredit ary panc reat it is by panc reat ography . Gast r oint est Endosc 1981;27:168–173. 282. Romijn MG, St oker J, v an Eijc k CHJ, et al. MRI w it h mangof odipir t risodium in t he det ec t ion and st aging of panc reat ic c anc er. J Magn Reson Im aging 2000;12:261–268.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2370

15 - The Pancreas 283. Ros PR, Hoon J. Mult isec t ion (mult idet ec t or) CT : applic at ions in t he abdomen. Radiogr aphic s 2002;22:697–700. 284. Rosc h T , Dit t ler HJ, St robel K, et al. Endosc opic ult rasound c rit eria f or

v asc ular inv asion in t he st aging of c anc er of t he head of t he panc reas: a blind reev aluat ion of v ideot apes. Gast r oint est Endosc 2000;52:469–477. 285. Ross BA, Jef f rey RB Jr, Mindelzun RE. Normal v ariat ions in t he lat eral c ont our of t he head and nec k of t he panc reas mimic king neoplasm: ev aluat ion w it h dual- phase helic al CT . AJR Am J Roent genol 1996;166:799–801. 286. Rubin E, Dunham WK, St anley RJ. Panc reat ic met ast ases in bone sarc omas: CT demonst rat ion. J Com put Assist T om ogr 1985;9: 886–888. 287. Rumanc ik WM, Megibow AJ, Bosniak MA, Hilt on S. Met ast at ic disease t o t he panc reas: ev aluat ion by c omput ed t omography . J Com put Assist T om ogr 1984;8:829–834. 288. Rust in RB, Broughan T A, Hermann RE, et al. Papillary c y st ic epit helial neoplasms of t he panc reas: a c linic al st udy of f our c ases. Ar c h Sur g 1986;121:1073–1076. 289. Sahani DV, Kalv a SP, F arrell J, et al. Aut oimmune panc reat it is: imaging f eat ures. Radiology 2004;233:345–352. 290. Saif uddin A, Ward J, Ridgw ay J, Chalmers AG. Comparison of MR and CT sc anning in sev ere ac ut e panc reat it is: init ial experienc es. Clin Radiol 1993;48:111–116. 291. Sarles H. Chronic c alc if y ing panc reat it is—c hronic alc oholic panc reat it is. Gast r oent er ology 1974;66:604–616. P.1099 292. Sarner M. Panc reat it is: def init ions and c lassif ic at ion. In: Go VLW, ed. T he exoc r ine panc r eas: biology , pat hobiology , and diseases. New Y ork: Rav en, 1986:459–464. 293. Sc at arige JC, Hort on KM, Shet h S, F ishman EK. Panc reat ic parenc hy mal met ast ases: observ at ion on helic al CT . AJR Am J Roent genol 2001;176:695–699. 294. Sc hima W, F ugger R, Sc hober E, et al. Diagnosis and st aging of panc reat ic c anc er: c omparison of mangof odipir t risodium- enhanc ed MR imaging and c ont rast - enhanc ed helic al hy dro CT . AJR Am J Roent genol 2002;179:717–724. 295. Sc hmidt J, Hot z H, F oit zik T , et al. Int rav enous c ont rast medium aggrav at es t he impairment of panc reat ic mic roc irc ulat ion in nec rot izing panc reat it is in t he rat . Ann Sur g 1995;221:257–264.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2371

15 - The Pancreas 296. Sc hult e SH, Baron RL, F reeny PC, et al. Root of t he superior mesent eric

art ery in panc reat it is and panc reat ic c arc inoma: ev aluat ion w it h CT . Radiology 1991;180:659–662. 297. Sc hw art z LH, Coakley F V, Sun Y , et al. Neoplast ic panc reat ic obiliary duc t obst ruc t ion: ev aluat ion w it h breat hhold MR c holangiopanc reat ography . AJR Am J Roent genol 1998;170:1491–1495. 298. Sc ot t J, Mart in I, Redhead D, et al. Muc inous c y st ic neoplasms of t he panc reas: imaging f eat ures and diagnost ic dif f ic ult ies. Clin Radiol 2000;55:187–192. 299. Sc ot t R, Jersky J, Hariparsad G. Case report : malignant giant c ell t umour of t he panc reas present ing as a large panc reat ic c y st . Br J Radiol 1993;66:1055–1057. 300. Semelka RC, Asc her SM. MR imaging of t he panc reas. Radiology 1993;188:593–602. 301. Semelka RC, Cumming MJ, Shoenut JP, et al. Islet c ell t umors: c omparison of dy namic c ont rast - enhanc ed CT and MR imaging w it h dy namic gadolinium enhanc ement and f at suppression. Radiology 1993;186:799–802. 302. Semelka RC, Kroeker MA, Shoenut JP, et al. Panc reat ic disease: prospec t iv e c omparison of CT , ERCP, and 1.5- T MR imaging w it h dy namic gadolinium enhanc ement and f at suppression. Radiology 1991;181:785–791. 303. Semelka RC, Shoenut JP, Kroeker MA, Mic f likier AB. Chronic panc reat it is: MR imaging f eat ures bef ore and af t er administ rat ion of gadopent et at e dimeglumine. J Magn Reson Im aging 1993; 3:79–82. 304. Shah KK, DeRidder PH, Sc hw ab RE, Alexander T J. CT diagnosis of dorsal panc reas agenesis. J Com put Assist T om ogr 1987;11: 170–171. 305. Sheiman RG, Rey nolds K, Rapt opoulos V. Alt erat ions in hepat ic perf usion result ing f rom splanc hnic v enous luminal c ompromise c aused by panc reat ic c arc inoma. AJR Am J Roent genol 2000; 175:105–108. 306. Sheridan MB, Ward J, Gut hrie JA, et al. Dy namic c ont rast enhanc ed MR imaging and dual phase helic al CT in t he preoperat iv e assessment of suspec t ed panc reat ic c anc er: a c omparat iv e st udy w it h rec eiv er operat ing c harac t erist ic analy sis: AJR Am J Roent genol 1999;173:583–590. 307. Shet h S, Hruban RK, F ishman EK. Helic al CT of islet c ell t umors of t he panc reas: t y pic al and at y pic al manif est at ions. AJR Am J Roent genol 2002;179:724–730.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2372

15 - The Pancreas 308. Shin HJ, Lahot i S, Sneige N. Endosc opic ult rasound- guided f ine- needle

aspirat ion in 179 c ases: t he M. D. Anderson Canc er Cent er experienc e. Canc er 2002;96:174–180. 309. Sht amler B, Bic kel A, Manor E, et al. Primary ly mphoma of t he head of t he panc reas. J Sur g Onc ol 1988;38:48–51. 310. Shuman WP, Cart er SJ, Mont ana MA, et al. Panc reat ic insuf f ic ienc y : role of CT ev aluat ion. Radiology 1986;158:625–627. 311. Sic a GT , Brav er J, Cooney MJ, et al. Comparison of endosc opic ret rograde c holangiopanc reat ography w it h MR c holangiopanc reat ography in pat ient s w it h panc reat it is. Radiology 1999;210: 605–610. 312. Siegelman ES, Mit c hell DG, Out w at er E, et al. Idiopat hic hemoc hromat osis: MR imaging f indings in c irrhot ic and prec irrhot ic pat ient s. Radiology 1993;188:637–641. 313. Silas AM, Morrin MM, Rapt opoulos V, Keogan MT . Int raduc t al papillary muc inous t umors of t he panc reas. AJR Am J Roent genol 2001;176:179–185. 314. Silv erman PM, Kalender WA, Hazle JD. Common t erminology f or single and mult islic e helic al CT . AJR Am J Roent genol 2001; 176:1135–1136. 315. Sim JS, Choi BS, Han JK, et al. Helic al CT anat omy of t he panc reat ic art eries. Abdom Im aging 1996;21:517–521. 316. Singer MV, Gy r K, Sarles H. Rev ised c lassif ic at ion of panc reat it is. Report of t he Sec ond Int ernat ional Sy mposium on t he Classif ic at ion of Panc reat it is in Marseille, F ranc e, Marc h 28- 30, 1984. Gast r oent er ology 1985;89:683–685. 317. Sironi S, DeCobelli F , Zerbi A, et al. Panc reat ic adenoc arc inoma: assessment of v asc ular inv asion w it h high- f ield MR imaging and a phased- array c oil. AJR Am J Roent genol 1996;167:997–1001. 318. Smet s Y F C, West endorp RG, Van der Pijl JW, et al. Ef f ec t of simult aneous panc reas- kidney t ransplant at ion on mort alit y of pat ient s w it h t y pe- 1 diabet es mellit us and end- st age renal disease. Lanc et 1999;353:1915–1919. 319. Smit h DR, St anley RJ, Rue LW III. Delay ed diagnosis of panc reat ic t ransec t ion af t er blunt abdominal t rauma. J T r aum a 1996;40: 1009–1013. 320. Sohn T A, Y eo CJ, Cameron JL, et al. Resec t ed adenoc arc inoma of t he panc reas- 616 pat ient s: result s, out c omes, and prognost ic indic at ors. J Gast r oint est Sur g 2000;4:567–579. 321. Sot o JA, Alv arez O, Munera F , et al. T raumat ic disrupt ion of t he panc reat ic duc t : diagnosis w it h MR panc reat ography . AJR Am J Roent genol 2001;176:175–178.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2373

15 - The Pancreas 322. Soy er P, Spelle L, Pelage JP, et al. Cy st ic f ibrosis in adolesc ent s and adult s: f at t y replac ement of t he panc reas- CT ev aluat ion and f unc t ional c orrelat ion. Radiology 1999;210:611–615. 323. Spenc er JA, Ward J, Gut hrie JA, et al. Assessment of resec t abilit y of panc reat ic c anc er w it h dy namic c ont rast - enhanc ed MR imaging: t ec hnique, surgic al c orrelat ion, and pat ient out c ome. Eur Radiol 1998;8:23–29. 324. St abile BE, Morrow DJ, Passaro E Jr. T he gast rinoma t riangle: operat iv e implic at ions. Am J Sur g 1984;147:25–31. 325. St af f ord- Johnson DB, F ranc is IR, Ec khauser F E, et al. Dual- phase helic al CT of nonf unc t ioning islet c ell t umors. J Com put Assist T om ogr 1998;22:335–339.

326. St ephenson CA, Klet zel M, Seibert JJ, Glasier CM. Panc reat oblast oma: MR appearanc e. J Com put Assist T om ogr 1990;14: 492–493. 327. St ojadinov ic A, Brooks A, Hoos A, et al. An ev idenc e- based approac h t o t he surgic al management of resec t able panc reat ic adenoc arc inoma. J Am Coll Sur g 2003;196:954–964. 328. St ollf uss JC, Glat t ing G, F riess H, et al. 2- (F luorine- 18)- f luoro- 2- deoxy D- gluc ose PET in det ec t ion of panc reat ic c anc er: v alue of quant it at iv e image int erpret at ion. Radiology 1995;195: 339–344. 329. Sugiy ama M, At omi Y , Hac hiy a J. Int raduc t al papillary t umors of t he panc reas: ev aluat ion w it h magnet ic resonanc e c holangiopanc reat ography . Am J Gast r oent er ol 1998;93:156–159. 330. T ada M, Komat su Y , Kaw abe T , et al. Quant it at iv e analy sis of K- ras gene mut at ion in panc reat ic t issue obt ained by endosc opic ult rasonography - guided f ine needle aspirat ion: c linic al ut ilit y f or diagnosis of panc reat ic t umor. Am J Gast r oent er ol 2002 97: 2263–2270. 331. T akahashi K, Y amao K, Okubo K, et al. Dif f erent ial diagnosis of panc reat ic c anc er and f oc al panc reat it is by using EUS- guided F NA. Gast r oint est Endosc 2005;61:76–79. 332. T amm EP, Silv erman PM, Charnsangav ej C, Ev ans DB. Imaging in onc ology f rom t he Univ ersit y of T exas MD Anderson Canc er Cent er. Diagnosis, st aging, and surv eillanc e of panc reat ic c anc er. AJR Am J Roent genol 2003;180:1311–1323. 333. T at li S, Mort ele KJ, Lev y AD, et al. CT and MRI f eat ures of pure ac inar c ell c arc inoma of t he panc reas in adult s. AJR Am J Roent genol 2005;184:511–519.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2374

15 - The Pancreas 334. T eef ey SA, St ephens DH, Sheedy PF II. CT appearanc e of primary panc reat it is ly mphoma. Gast r oint est Radiol 1986;11:41–43. 335. T hompson NW, Ec khauser F E, Vinik AI, et al. Cy st ic neuroendoc rine neoplasms of t he panc reas and liv er. Ann Sur g 1984;199: 158–164. 336. T oombs BD, Lest er RG, Ben- Menac hem Y , Sandler CM. Comput ed t omography in blunt t rauma. Radiol Clin Nor t h Am 1981;19: 17–35. 337. T orres WE, Clement s JL, Sones PJ, Knopf DR. Gas in t he panc reat ic bed w it hout absc ess. AJR Am J Roent genol 1981;137: 1131–1133. P.1100 338. T rellis DR, Clouse RE. Johanson- Blizzard sy ndrome. Progression of panc reat ic inv olv ement in adult hood. Dig Dis Sc i 1991;36: 365–369. 339. T suc hiy a R, Noda T , Harada N. et al. Collec t iv e rev iew of small c arc inomas of t he panc reas. Ann Sur g 1986;203:77–81. 340. T ublin ME, T essler F N, Cheng SL, et al. Ef f ec t of injec t ion rat e of c ont rast medium n panc reat ic and hepat ic helic al CT . Radiology 1999;210:97–101. 341. Uc hiy ama T , Suzuki T , Adac hi A, et al. Panc reat ic pleural ef f usion: c ase report and rev iew of 113 c ases in Japan. Am J Gast r oent er ol 1992;87:387–391. 342. Valls C, Andia E, Sanc hez A, et al. Dual phase helic al CT of panc reat ic adenoc arc inoma: assessment of resec t abilit y bef ore surgery . AJR Am J Roent genol 2002;178:821–826. 343. Van Hoe L, Gry speerdt S, Marc hal G, et al. Helic al CT f or t he

preoperat iv e loc alizat ion of islet c ell t umors of t he panc reas: Value of art erial and parenc hy mal phase images. AJR Am J Roent genol 1995;165:1437–1439. 344. v anSonnenberg E, Wit t ic h GR, Casola G, et al. Perc ut aneous drainage of inf ec t ed and noninf ec t ed panc reat ic pseudoc y st s: experienc e in 101 c ases. Radiology 1989;170:757–761. 345. v anSonnenberg E, Wit t ic h GR, Chon KS, et al. Perc ut aneous radiologic drainage of panc reat ic absc esses. AJR Am J Roent genol 1997;168:979–984. 346. Vedant ham S, Lu DSK, Reber HA, Kadell B. Small peripanc reat ic v eins: improv ed assessment in panc reat ic c anc er pat ient s using t hin- sec t ion panc reat ic phase helic al CT . AJR Am J Roent genol 1998;170:377–383. 347. Vinik AI, St rodel WE, Ec khauser F E, et al. Somat ost at inomas, PPomas, neurot ensinomas. Sem in Onc ol 1987;14:263–281.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2375

15 - The Pancreas 348. Ward J, Chalmers AG, Gut hrie AJ, et al. T 2 w eight ed and dy namic enhanc ed MRI in ac ut e panc reat it is: c omparison w it h c ont rast enhanc ed CT . Clin Radiol 1997;52:109–114.

349. Warshaw AL, Rat t ner DW, F ernandez- del- c ast illo C. Int rav enous c ont rast does aggrav at e experiment al panc reat it is. Gast r oent er ology 1994;107:320–321. 350. Webb T H, Lillemoe KD, Pit t HA, et al. Panc reat ic ly mphoma. Is surgery mandat ory f or diagnosis or t reat ment ? Ann Sur g 1989;209:25–30. 351. West JH, Vogel SB, Drane WE. Gallium upt ake in c omplic at ed panc reat it is: a predic t or of inf ec t ion. AJR Am J Roent genol 2002; 178:841–846. 352. Wey man PJ, St anley RJ, Lev it t RG. Comput ed t omography in ev aluat ion of t he panc reas. Sem in Roent genol 1981;16:301–311. 353. Whang EE, Danial T , Dunn JC, et al. T he spec t rum of muc in- produc ing adenoc arc inoma of t he panc reas. Panc r eas 2001;21: 147–151. 354. Whit e EM, Wit t enberg J, Mueller PR, et al. Panc reat ic nec rosis: CT manif est at ions. Radiology 1986;158:343–346. 355. Wiersema MJ. Ac c urac y of endosc opic ult rasound in diagnosing and st aging panc reat ic c arc inoma. Panc r eat ology 2001;1:625–632. 356. Wildling R, Sc hnedl WJ, Reisinger EC, et al. Agenesis of t he dorsal panc reas in a w oman w it h diabet es mellit us and in bot h of her sons. Gast r oent er ology 1993;104:1182–1186. 357. Wilent z RE, Albores- Saav edra J, Hruban RH. Muc inous c y st ic neoplasms of t he panc reas. Sem in Diagn Pat hol 2000;17: 31–42. 358. Wilson T E, Korobkin M, F ranc is IR. Panc reat ic plasmac y t oma: CT f indings. AJR Am J Roent genol 1989;152:1227–1228. 359. Wingo PA, T ong T , Bolden S. Canc er st at ist ic s, 1995. Ca Canc er J Clin 1995;45:8–30. 360. Wint er T C, F reeny PC, Nghiem HV. Ext rapanc reat ic gast rinoma loc alizat ion: v alue of art erial- phase helic al CT w it h w at er as an oral c ont rast agent . AJR Am J Roent genol 1996;166:51–52. 361. Winset t MZ, Kumar R, Balac handran S, et al. Pseudoc y st f ollow ing splenec t omy : impac t of CT and ult rasound on it s diagnosis and management . Gast r oint est Radiol 1988;13:177–179. 362. Wise RH Jr, St anley RJ. Carc inoma of t he ampulla of Vat er present ing as ac ut e panc reat it is. J Com put Assist T om ogr 1984;8: 158–161. 363. Wit t enberg J, Simone JF , F erruc c i JT Jr, et al. Non- f oc al enlargement in panc reat ic c arc inoma. Radiology 1982;144:131–135.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2376

15 - The Pancreas 364. Wolf EL, Spray regen S, F rager D, et al. Calc if ic at ion in an insulinoma of t he panc reas. Am J Gast r oent er ol 1984;79:559–561. 365. Wolf man NT , Karst aedt N, Kaw amot o EH. Pleomorphic c arc inoma of t he panc reas: c omput ed- t omographic , sonographic , and pat hologic f indings. Radiology 1985;154:329–332. 366. Wong JJ, Krebs T L, Klassen DK, et al. Sonographic ev aluat ion of ac ut e panc reat ic t ransplant rejec t ion: morphology - Doppler analy sis v ersus guided perc ut aneous biopsy . AJR Am J Roent genol 1996;166:803–807. 367. Wong Y c , Wang LJ, Lin BC, et al. CT grading of panc reat ic injuries: predic t ion of duc t al disrupt ion and surgic al c orrelat ion. J Com put Assist T om ogr 1997;21:246–250. 368. Y amada Y , Mori H, Kiy osue H, et al. CT assessment of t he inf erior peripanc reat ic v eins: c linic al signif ic anc e. AJR Am J Roent genol 2000;174:677–684. 369. Y amao K, Ohashi K, Nakamura T , et al. Ev aluat ion of v arious imaging met hods in t he dif f erent ial diagnosis of int raduc t al papillary - muc inous t umor (IPMT ) of t he panc reas. Hepat ogast r oent er ology 2001;48:962–966. 370. Y eh HC, St anc at o- Pasik A, Shapiro RS. Mic roc y st ic f eat ures at US: a nonspec if ic sign f or mic roc y st ic adenomas of t he panc reas. Radiogr aphic s 2001;21:1455–1461. 371. Y eo CS, Cameron JL. Panc reat ic c anc er. Cur r Pr obl Sur g 1999; 36:57–152. 372. Y oshida K, T oki F , T akeuc hi T , et al. Chronic panc reat it is c aused by an

aut oimmune abnormalit y : proposal of t he c onc ept of aut oimmune panc reat it is. Dig Dis Sc i 1995;40:1561–1568. 373. Zeman RK, Mc Vay L, Silv erman PM, et al. T hin sec t ion CT of panc reas div isum. In: Sy llabus of t he Soc iet y of Gast r oint est inal Radiologist s, Sev ent eent h Annual Meet ing and Post graduat e Course, January 16- 20, 1988, Nassau, Bahamas, p. 31(abst ). 374. Zerby AL, Lee MJ, Brugge WR, Mueller PR. Endosc opic sonography of t he upper gast roint est inal t rac t and panc reas. AJR Am J Roent genol 1996;166:45–50. 375. Zimny M, Bares R, F ass J, et al. F luorine- 18 f luorodeoxy gluc ose posit ron emission t omography in t he dif f erent ial diagnosis of panc reat ic c arc inoma: a report of 106 c ases. Eur J Nuc l Med 1997;24:678–682.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

16 - Abdominal Wall and Peritoneal Cavity

2378

16 - Abdominal Wall and Peritoneal Cavity 21

16 - Abdominal Wall and Peritoneal Cavity Editors: Le e , Jose ph K. T. ; Sa ge l, Stua rt S. ; Sta nle y , Robe rt J. ; He ike n, Ja y P. Title : C ompute d Body Tomogra phy with MRI C orre la tion , 4th Edition Copy right В©2006 Lippinc ot t Williams & Wilkins > T able of Cont ent s > 16 - Abdominal Wall and Perit oneal Cav it y

16 Abdominal Wall and Peritoneal Cavity Ja y P. He ike n C hristine O. Me nia s Kha le d Elsa y e s

ABDOMINAL WALL Anatomy T he normal anat omy of t he abdominal w all is disc ussed in Chapt er 10.

Pathology Hernias Alt hough t he diagnosis of hernia usually c an be est ablished c linic ally , c omput ed t omography (CT ) may be usef ul in selec t inst anc es in dif f erent iat ing bet w een a hernia and a mass w it hin t he abdominal c av it y or abdominal w all (219). CT also c an demonst rat e sy mpt omat ic inc isional hernias in pat ient s w ho are dif f ic ult t o examine, suc h as obese indiv iduals, t hose in t he early post operat iv e period, and t hose w it h abdominal w all sc ars. In addit ion, CT may rev eal c linic ally unsuspec t ed inc isional hernias in pat ient s undergoing post operat iv e CT examinat ions and may show v ent ral hernias in pat ient s w ho hav e sust ained blunt or penet rat ing abdominal t rauma (84,155,224). CT is usef ul in demonst rat ing t he size of t he hernia sac and t he underly ing f asc ial def ec t , as w ell as t he hernia c ont ent and any assoc iat ed c omplic at ions suc h as bow el obst ruc t ion, isc hemia, or inf arc t ion. Ac quiring t he CT images w hile t he pat ient perf orms t he Valsalv a maneuv er t o inc rease int ra- abdominal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2379

16 - Abdominal Wall and Peritoneal Cavity pressure c an aid in demonst rat ing some hernias, part ic ularly t hose inv olv ing t he v ent ral abdominal w all (68,116,121,127). A v ent ral hernia is produc ed w hen t he linea alba is disrupt ed and f at and/or bow el herniat e ant eriorly t hrough t he def ec t (F ig. 16- 1). An inc isional hernia c an oc c ur at any abdominal w all surgic al inc ision sit e, inc luding a laparosc opic port sit e (F ig. 16- 2). A Spigelian hernia result s f rom w eakness in t he int ernal oblique and

t ransv ersus aponeuroses, allow ing perit oneal c ont ent s t o herniat e beneat h an int ac t ext ernal oblique musc le. CT c an est ablish t he diagnosis by demonst rat ing a perit oneal and musc ular def ec t at t he lat eral border of t he rec t us sheat h (18) (F igs. 16- 3 and 16- 4). Lumbar hernias c an oc c ur at t w o w eak point s in t he post erolat eral abdominal w all (15,153). T he low er of t he t w o w eak point s, c alled t he inf er ior lum bar t r iangle, or Pet it 's t r iangle, lies just abov e t he iliac c rest bet w een t he ext ernal oblique and lat issimus dorsi musc les (15,153). T he larger point is c alled t he super ior lum bar t r iangle, or Gr y nf elt 's t r iangle, and is bounded by t he 12t h rib, t he serrat us post ic us musc le, t he int ernal oblique musc le, and t he erec t or spinae musc les. T hese rare post erior abdominal w all hernias may c ont ain int raperit oneal or ext raperit oneal c ont ent s. T he indirec t inguinal hernia, t he most c ommon t y pe of ext ernal abdominal hernia, result s f rom herniat ion of perit oneal c ont ent s t hrough t he deep inguinal ring (F ig. 16- 5). If suf f ic ient ly large, t he hernia sac may ext end int o t he sc rot um in men or int o t he labium majorum in w omen. A f emoral hernia result s w hen perit oneal c ont ent s ent er t he f emoral c anal adjac ent t o t he f emoral art ery and v ein. In t his t y pe of hernia, t he sac prot rudes lat eral t o t he inguinal c anal bet w een t he ext ernal oblique musc le insert ion on t he superior pubic ramus and t he superior pubic ramus it self (265). It is of t en dif f ic ult t o dist inguish small inguinal and f emoral hernias radiographic ally (3,328). T he most P.1102 c ommon t y pe of obt urat or hernia result s w hen int raperit oneal or ext raperit oneal c ont ent s prot rude bet w een t he pec t ineus and ext ernal obt urat or musc les (F ig. 16- 6) (189). Less c ommonly , herniat ion oc c urs bet w een t he ext ernal and int ernal obt urat or musc les (F ig. 16- 7) or bet w een t he f asc ic uli of t he ext ernal obt urat or musc le.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2380

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 1 Vent ral hernia. A small bow el loop (SB) has herniat ed ant eriorly t hrough a w ide def ec t in t he linea alba; not e edema of t he small bow el mesent ery .

Masses: Hematoma Abdominal w all hemat omas oc c ur most c ommonly w it hin t he sheat h of t he rec t us abdominis musc le and are most of t en sec ondary t o ant ic oagulant t herapy , alt hough t hey may oc c ur w it h v arious disease st at es, abdominal w all t rauma, and sev ere exert ion (25,77,240). Clinic al f indings t hat suggest an abdominal w all hemat oma inc lude ac ut e onset of abdominal pain in assoc iat ion w it h a palpable mass, disc olorat ion of t he skin ov erly ing t he mass, and a dec reasing hemat oc rit . Of t en t he c linic al present at ion is one of ac ut e abdominal pain alone, and CT c an est ablish t he diagnosis of hemat oma, exc luding ot her int raperit oneal et iologies. CT may ac c urat ely assess t he ext ent of hemat oma and det ermine if a c onc omit ant int ra- abdominal or ret roperit oneal hemat oma is present .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2381

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 2 Laparosc opic port sit e hernia. Herniat ion of a small bow el loop (ar r ow heads) t hrough a f asc ial def ec t (ar r ow ) just lat eral t o t he rec t us abdominis musc le has result ed in small bow el obst ruc t ion.

F igure 16- 3 Spigelian hernia. Oment al f at prot rudes t hrough a def ec t in t he right linea semilunaris (ar r ow ) but is c ont ained by an int ac t ext ernal oblique musc le (ar r ow heads). T he hernia sac may be c onf used w it h an abdominal w all lipoma if t he musc ular def ec t is not rec ognized.

T he CT appearanc e of abdominal w all hemat oma is t hat of an abnormal mass, of t en ellipt ic al or spindle- shaped,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2382

16 - Abdominal Wall and Peritoneal Cavity P.1103 in one or more lay ers of t he abdominal w all, enlarging, oblit erat ing, or displac ing normal st ruc t ures (F ig. 16- 8A). Rec t us sheat h hemat omas are

usually limit ed t o one side of t he abdomen by t he linea alba. Large hemat omas may , how ev er, dissec t inf eriorly along f asc ial planes and ext end int o t he pelv is, c ompressing v isc era and c rossing t o t he c ont ralat eral side (221). An ac ut e abdominal w all hemat oma has a densit y equal t o or great er P.1104 t han t he densit y of t he abdominal musc les bec ause of t he high prot ein c ont ent of hemoglobin. Of all body w all hemat omas sc anned w it hin t he f irst 2 w eeks af t er hemorrhage, 75% are hy perdense and of t en het erogeneous (288). On oc c asion, a f luid–f luid lev el c an be seen as a result of t he set t ling of c ellular element s w it hin t he hemat oma (“ t he hemat oc rit ef f ec t ” ) (F ig. 16- 8B). As t he hemat oma mat ures, t he progressiv e breakdow n and remov al of prot ein w it hin red blood c ells reduc es t he at t enuat ion v alue of t he hemat oma (203). T he proc ess of c lot ly sis of t en oc c urs in a c ent ripet al f ashion, produc ing a low - at t enuat ion halo at t he periphery t hat w idens as ly sis progresses. By 2 t o 4 w eeks af t er t he init ial bleeding episode, t he densit y of t he hemat oma may approac h t hat of serum (20 t o 30 HU) and t hen remains serum densit y f or t he durat ion of it s exist enc e. Wit h t ime a f ibroblast ic and v asc ular membrane (pseudoc apsule) grow s around t he hemat oma, produc ing a dense rim on CT images. On oc c asion, t he periphery of a c hronic hemat oma (seroma) may c alc if y .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2383

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 4 Spigelian hernia w it h small bow el obst ruc t ion. Herniat ion of a small bow el loop (ar r ow ) t hrough a def ec t in t he right linea semilunaris has result ed in a high- grade small bow el obst ruc t ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2384

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 5 Bilat eral inguinal hernias. T ransaxial pelv ic c omput ed t omography (A) and v olume- rendered c oronal (B) and sagit t al (C ) ref ormat t ed images show small bow el loops and small bow el mesent ery herniat ed t hrough bilat eral f asc ial def ec t s. T he aponeurosis of t he ext ernal oblique musc le (ar r ow ) f orms t he ant erior w all and t he aponeurosis of t he t ransv ersus musc le (ar r ow head) f orms t he post erior w all of t he c anal.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2385

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 6 Obt urat or hernia c ausing small bow el obst ruc t ion. A: A loop of small bow el (ar r ow ) has herniat ed bet w een t he pec t ineus (p) and ext ernal obt urat or (eo) musc les.B: A more c ephalad image show s dilat ed, obst ruc t ed small bow el loops.

F igure 16- 7 Obt urat or hernia c ausing small bow el obst ruc t ion.A: In t his pat ient t he hernia sac , w hic h c ont ains a small bow el loop (ar r ow ), passes bet w een t he ext ernal (ar r ow head) and int ernal (open ar r ow ) obt urat or musc les, a less c ommon f orm of obt urat or hernia t han t hat seen in F igure 166.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2386

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 8 Abdominal w all hemat omas.A: Unenhanc ed c omput ed t omography show s spindle shaped enlargement and high at t enuat ion (ar r ow ) in t he lef t rec t us abdominis musc le. Not e t he ext raperit oneal hemorrhage (ar r ow heads) in t he lef t side of t he pelv is.B: A c ont rast - enhanc ed image in anot her pat ient demonst rat es an ov al f luid c ollec t ion (ar r ow s) w it h a hemat oc rit lev el in t he right rec t us abdominis musc le sheat h.

P.1105 T he MRI appearanc e of abdominal w all hemat oma undergoes an ev olut ion similar t o t hat seen on CT . In addit ion t o age, t he MRI appearanc e of a hemat oma depends on t he magnet ic f ield st rengt h at w hic h it is imaged and t he pulse sequenc e used. When examined at high magnet ic f ield st rengt h (1.5 T ), an ac ut e hemat oma has a signal int ensit y similar t o t hat of musc le on longit udinal relaxat ion t ime (T 1)- w eight ed images w it h marked hy point ensit y on t ransv erse relaxat ion t ime (T 2)- w eight ed images (252). T he prominent hy point ensit y on T 2- w eight ed images implies pref erent ial T 2 prot on relaxat ion enhanc ement (89). It has been proposed t hat t he high c onc ent rat ion of F e 2+deoxy hemoglobin inside int ac t red blood c ells in ac ut e hemat omas c reat es loc al het erogeneit y of magnet ic susc ept ibilit y , result ing in pref erent ial T 2 prot on relaxat ion enhanc ement (89). T his T 2- short ening ef f ec t is more pronounc ed w it h a gradient - ec ho sequenc e t han w it h a spin- ec ho t ec hnique. Large ac ut e hemat omas may demonst rat e a f luid–f luid lev el on MR images, similar t o t hat seen on CT . On CT , t he dependent port ion of t he hemat oma is high in at t enuat ion. On T 1- w eight ed MR images, t he dependent port ion is hy perint ense c ompared w it h t he supernat ant , w hereas on T 2- w eight ed images t his signal int ensit y relat ionship is rev ersed (102).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2387

16 - Abdominal Wall and Peritoneal Cavity Subac ut e hemat omas (older t han 1 w eek) hav e a more c harac t erist ic MRI appearanc e on T 1- w eight ed images, c onsist ing of a medium- signal- int ensit y (slight ly great er t han musc le) c ent ral area c orresponding t o t he highat t enuat ion area on CT , surrounded by a high- int ensit y ring c orresponding t o

t he area of low at t enuat ion on CT , w hic h in t urn is surrounded by a t hin rim of v ery low signal int ensit y (102,252,297). On T 2- w eight ed images, t he signal int ensit y of t he c ent ral c ore is similar t o t hat of t he peripheral zone. T he t hin out er rim remains v ery low in signal int ensit y . T he high signal int ensit y of subac ut e hemat omas is a result of T 1 short ening c aused by t he presenc e of ext rac ellular met hemoglobin result ing f rom oxidat iv e denat urat ion of hemoglobin (28).

Inflammation/Infection Inf lammat ion in t he abdominal w all is most of t en t he result of inf ec t ion, most c ommonly post operat iv e w ound inf ec t ion (323). Ot her less c ommon c auses inc lude t rauma, direc t ext ension f rom int ra- abdominal inf lammat ory proc esses, and alt ered host def ense (266). Clinic al diagnosis of an abdominal w all inf ec t ion is of t en dif f ic ult , espec ially in early post operat iv e or obese pat ient s. T he ext ent of t issue inv olv ement is of t en underest imat ed by phy sic al examinat ion. CT c an be usef ul in dif f erent iat ing absc ess f rom c ellulit is, diagnosing or exc luding inf ec t ion in pat ient s w it h post operat iv e w ound t enderness, delineat ing t he size and ext ent of an absc ess w hen present , and det ermining w het her or not t he perit oneal c av it y is inv olv ed. T he CT f indings of abdominal w all inf lammat ion are nonspec if ic and inc lude st reaky sof t t issue densit ies, loss of normal int ermusc ular f at planes, enlargement of abdominal w all musc les, loc alized masses of v ary ing densit y , and masses t hat dissec t along f asc ial planes. An abdominal w all absc ess appears as an abnormal mass t hat usually has a low - at t enuat ion c ent ral zone (F ig. 16- 9). T he peripheral zone or w all of t he absc ess may enhanc e af t er administ rat ion of int rav enous iodinat ed c ont rast mat erial. Oc c asionally , gas, result ing f rom gas- produc ing organisms, may be present in an abdominal w all absc ess. How ev er, t he presenc e of gas w it hin t he abdominal w all is not a spec if ic sign of absc ess bec ause gas in a part ially open abdominal w ound or gas in a f ist ula c onnec t ing bow el t o t he skin surf ac e P.1106 may appear similar. Bec ause t he CT appearanc e of absc ess is not spec if ic , needle aspirat ion may be nec essary t o c onf irm t he diagnosis. Bot h MRI and CT

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2388

16 - Abdominal Wall and Peritoneal Cavity are ef f ec t iv e in demonst rat ing and c harac t erizing abdominal w all inf ec t ions. T he mult iplanar c apabilit y of CT and MRI c an be of part ic ular help in def ining int raperit oneal ext ension and in surgic al planning (113,266).

F igure 16- 9 Abdominal w all absc ess. T he right rec t us abdominis musc le c ont ains a low at t enuat ion f luid c ollec t ion w it h an enhanc ing w all (ar r ow heads).

Other Nonneoplastic Entities Endomet rial implant s in t he abdominal w all c an oc c ur in laparot omy inc isions or in t he t rac t s of inst rument port s f rom laparosc opy (F igs. 16- 10 and 16- 11). Alt hough t hese implant s usually result f rom proc edures t hat expose t he endomet rial c av it y , suc h as c esarean sec t ion (317), seeding also c an oc c ur f rom adnexal or perit oneal endomet riosis. CT may demonst rat e a sof t t issue at t enuat ion mass t hat is dif f ic ult t o dif f erent iat e f rom t he adjac ent abdominal w all musc ulat ure. MRI may show high signal int ensit y on T 1- and T 2- w eight ed images result ing f rom hemorrhage (F ig. 16- 12). Het erot opic ossif ic at ion, a f orm of my osit is ossif ic ans t raumat ic a, c an oc c ur in midline abdominal surgic al inc isions. T he osseous, c art ilaginous, and, less c ommonly , marrow element s are responsible f or t he predic t able CT appearanc e of sof t t issue, bone, and somet imes f at at t enuat ion c omponent s. Rec ognit ion of t his lesion allow s dist inc t ion f rom ot her ent it ies suc h as post operat iv e hemat oma or inf ec t ion, ret ained f oreign body , and primary or met ast at ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2389

16 - Abdominal Wall and Peritoneal Cavity malignanc y (125). Exuberant sc ar f ormat ion in an abdominal w all w ound (keloid), appears as a superf ic ial sof t t issue mass c ent ered w it hin t he skin ov erly ing an inc ision sit e. On MR images, it demonst rat es low signal int ensit y on bot h T 1- and T 2- w eight ed images.

F igure 16- 10 Abdominal w all endomet rioma. Pelv ic c omput ed t omography show s a small enhanc ing sof t t issue mass (ar r ow heads) w it hin t he lef t rec t us abdominis musc le in t his pat ient w ho prev iously had undergone laparosc opy f or endomet riosis.

Dif f use lipomat osis of t he abdominal w all is a benign c ondit ion t hat may be impossible t o dif f erent iat e f rom a w ell- dif f erent iat ed liposarc oma w it h CT or MRI, requiring hist ologic diagnosis (53).

Neoplasms Bot h primary and sec ondary neoplasms c an inv olv e t he abdominal w all. Alt hough large masses generally are disc ov ered by inspec t ion and palpat ion, small t umors may be dif f ic ult t o det ec t c linic ally , part ic ularly in obese pat ient s or in t hose w it h surgic al sc ars or indurat ed t issue. CT is c apable of demonst rat ing small abdominal w all t umors and may be v aluable in def ining t he ext ent of palpable lesions f or t he purpose of plac ing radiot herapy port s and assessing t he ef f ec t iv eness of c hemot herapy . CT is also helpf ul in det ec t ing t umor rec urrenc e af t er surgic al exc ision (66).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2390

16 - Abdominal Wall and Peritoneal Cavity Lipomas are c ommon, benign t umors t hat c an be f ound t hroughout t he body , inc luding t he subc ut aneous f at or musc le lay ers of t he abdominal w all. T hey

are w ell- def ined, homogeneous, f at at t enuat ion (- 40 t o - 100 HU) masses t hat may c ont ain t hin sof t t issue sept a and v essels. Desmoid t umors are loc ally aggressiv e, benign f ibrous t issue neoplasms t hat oc c ur most c ommonly in t he musc uloaponeurot ic f asc ia of t he ant erior abdominal w all, usually in t he rec t us abdominis and int ernal oblique musc les and t heir f asc ial c ov erings. Approximat ely t hree f ourt hs of abdominal w all desmoids oc c ur in w omen, predominant ly during t he c hildbearing y ears (29). On prec ont rast CT images, desmoid t umors hav e an at t enuat ion v alue similar to P.1107 t hat of musc le, but t hey may enhanc e af t er c ont rast medium administ rat ion t o bec ome hy perdense relat iv e t o musc le (F ig. 16- 13) (117). On MR images, desmoid t umors c ommonly appear isoint ense t o musc le on T 1- w eight ed images, v ariable in signal int ensit y on T 2- w eight ed images, and demonst rat e dif f use enhanc ement af t er int rav enous administ rat ion of gadolinium (246). Ext ensiv e f ibrosis is suggest ed by areas of low signal int ensit y on bot h T 1- and T 2w eight ed images (122). T hese MR signal c harac t erist ic s are nonspec if ic , but suggest iv e in t he proper c linic al set t ing. T he mult iplanar c apabilit y of MRI and mult idet ec t or CT is helpf ul in def ining t he c onnec t ion of t he mass t o t he abdominal w all musc le or f asc ia (122).

F igure 16- 11 Umbilic al endomet riosis. Sof t t issue at t enuat ion prominenc e of t he umbilic us (ar r ow head) represent s seeding of a laparosc opy t rac t by

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2391

16 - Abdominal Wall and Peritoneal Cavity endomet riosis. T his pat ient experienc ed c y c lic umbilic al bleeding, c orresponding t o her menst rual c y c le.

Neurof ibromas, seen most c ommonly in pat ient s w it h neurof ibromat osis, of t en appear as homogeneous sof t t issue masses of v ary ing size inv olv ing t he skin and subc ut aneous f at (F ig. 16- 14). T he at t enuat ion of abdominal w all neurof ibromas is usually similar t o t hat of skelet al musc le. T he most c ommon primary malignant neoplasms of t he abdominal w all are sarc omas (F ig. 16- 15), f ollow ed in f requenc y by ly mphomas. Hemat ogenously spread met ast ases may inv olv e eit her t he abdominal w all musc les (F ig. 16- 16) or t he subc ut aneous f at . Met ast at ic inv olv ement of musc le produc es enlargement of t he musc le, of t en w it h an assoc iat ed alt erat ion in normal at t enuat ion v alue. Subc ut aneous met ast ases usually are nodular, and are readily demonst rat ed at CT as sof t t issue at t enuat ion masses in t he low er at t enuat ion subc ut aneous f at (222). Direc t spread t o t he abdominal w all by an int ra- abdominal neoplasm appears as a t hic kening of t he musc les w it h loss of t he int ermusc ular and perimusc ular f at planes (219). Malignant neoplasms t hat spread int raperit oneally , suc h as ov arian and gast roint est inal t rac t c arc inomas, hav e a t endenc y t o inv olv e t he umbilic al region, produc ing periumbilic al masses. Suc h periumbilic al met ast ases are somet imes ref erred t o as Sist er Mar y Joseph nodules, named af t er t he f irst assist ant t o Dr. William May o, w ho w hile preparing pat ient s' abdomens prior t o surgery in t he early day s of t he May o Clinic , observ ed t hat pat ient s w it h adv anc ed int ra- abdominal malignanc y of t en had umbilic al nodules (52). Abdominal w all met ast ases of c olon, ov arian, gast ric , and gallbladder c arc inoma hav e been report ed in inc isions and port sit es af t er laparosc opy (F ig. 16- 17) (23,33,48,86,126,129,306). Dif f erent iat ion of abdominal w all neoplasm f rom absc ess or hemat oma may not be possible using CT c rit eria alone and c linic al c orrelat ion is of t en nec essary . Perc ut aneous needle biopsy under ult rasound or CT guidanc e may be required t o dif f erent iat e among t hese ent it ies.

PERITONEAL CAVITY Anatomy T he perit oneal c av it y c ont ains a series of c ommunic at ing but c ompart ment alized pot ent ial spac es t hat are not v isualized on CT unless t hey are dist ended by f luid. Know ledge of t he anat omy of t hese spac es and of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2392

16 - Abdominal Wall and Peritoneal Cavity ligament s t hat def ine t hem is import ant in t he underst anding of pat hologic proc esses inv olv ing t he perit oneal c av it y .

T he w alls of t he perit oneal c av it y , as w ell as t he abdominal and pelv ic organs c ont ained w it hin, are lined w it h perit oneum, an areolar membrane c ov ered by a single row of mesot helial c ells (93). F olds of perit oneum, c alled ligam ent s, c onnec t and prov ide support f or st ruc t ures w it hin t his c av it y . T he name of a part ic ular ligament usually ref lec t s t he t w o major st ruc t ures t hat it joins (e.g., t he gast roc olic ligament P.1108 ext ends bet w een t he great er c urv at ure of t he st omac h and t he t ransv erse c olon). A ligament t hat c onnec t s t he st omac h t o ot her st ruc t ures is c alled an om ent um . T he great er oment um joins t he great er c urv at ure of t he st omac h t o t he c olon and t hen c ont inues dow nw ard ant erior t o t he small bow el. T he lesser oment um (also c alled t he gast r ohepat ic ligam ent ) joins t he lesser c urv at ure of t he st omac h t o t he liv er. A mesent ery is a f old of perit oneum c onnec t ing eit her t he small bow el or port ions of t he c olon t o t he post erior abdominal w all. Normally , t hese perit oneal f olds are not direc t ly imaged by CT , but f at , ly mph nodes, and v essels c ont ained w it hin t hem c an be ident if ied (273). When t he perit oneal f olds bec ome t hic kened by edema, inf lammat ion, or neoplast ic inf ilt rat ion, t hey c an be direc t ly v isualized on CT . Ligament s, oment a, and mesent eries c an serv e as rout es of spread of benign and malignant pat hologic proc esses w it hin t he perit oneal c av it y , as w ell as bet w een t he perit oneum and t he ret roperit oneum (9,62,185,217). T he mode of spread c an be by direc t ext ension or v ia t he ly mphat ic s, v essels, or nerv es in t he areolar t issue enc losed by perit oneum (9,62,41,42,185,213,214,215,216,217), ref erred t o by some aut hors as t he subper it oneal spac e (185,216). Know ledge of t hese st ruc t ures is import ant in image int erpret at ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2393

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 12 Umbilic al endomet riosis. Magnet ic resonanc e imaging demonst rat es t hic kening of t he umbilic us w hic h is int ermediat e in signal int ensit y on T 1- w eight ed (A) and high in signal int ensit y on T 2- w eight ed (B) images.

T he major barrier div iding t he perit oneal c av it y is t he t ransv erse mesoc olon, w hic h separat es t he c av it y int o supramesoc olic and inf ramesoc olic c ompart ment s (181). An underst anding of t he anat omy of t he supramesoc olic c ompart ment is aided by f amiliarit y w it h t he embry ologic dev elopment of t his spac e (disc ussed in Chapt er 10).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2394

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 13 Desmoid t umor. Cont rast - enhanc ed c omput ed t omography show s a homogeneously enhanc ing mass (ar r ow ) inv olv ing t he lef t rec t us abdominis musc le in t his pat ient , w ho has undergone a c olec t omy f or f amilial adenomat ous poly posis.

P.1109

Supramesocolic Compartment In t he f ollow ing disc ussion, t he lef t and right perit oneal spac es are arbit rarily div ided int o a number of subspac es. Alt hough t hese spac es f reely c ommunic at e, t hey of t en bec ome separat ed by f ibrous adhesions w hen inf lammat ory or neoplast ic proc esses c ause f luid t o c ollec t in t hese spac es. (F or a c omplet e disc ussion of t he anat omy of t he perit oneal spac es, see Chapt er 10.)

Left Peritoneal Space T he lef t perit oneal spac e c an be div ided int o ant erior and post erior perihepat ic and ant erior and post erior subphrenic spac es. T he lef t ant erior perihepat ic spac e c an be af f ec t ed by pat hology emanat ing f rom t he lef t lobe of t he liv er or t he ant erior w all of t he body and ant rum of t he st omac h (F ig. 16- 18). In addit ion, it may be inv olv ed by ext ension of pat hologic proc esses f rom ot her port ions of t he lef t perit oneal spac e (F ig. 16- 19).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2395

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 14 Neurof ibromat osis t y pe 1. A andB: Comput ed t omography show s homogeneous sof t t issue at t enuat ion masses w it hin t he subc ut aneous f at (ar r ow heads) and t he mesent eric and oment al f at (ar r ow s).

T he lef t post erior perihepat ic spac e is also ref erred t o as t he gast r ohepat ic r ec ess. T his spac e may be af f ec t ed by pat hologic proc esses arising in any of t he st ruc t ures t o w hic h it is c losely relat ed, inc luding t he lef t lobe of t he liv er, t he lesser c urv at ure of t he st omac h, t he ant erior w all of t he duodenal bulb, and t he ant erior w all of t he gallbladder (307). T he lef t ant er ior subphr enic spac e is in direc t c ont inuit y w it h t he lef t ant erior perihepat ic spac e inf eromedially and w it h t he lef t post erior subphrenic spac e dorsally (117,283) (F igs. 16- 20, 16- 21, and 16- 22). F luid c ollec t ions in t his region may result f rom perf orat ion of t he splenic f lexure of t he c olon or of t he f undus or upper body of t he st omac h. In addit ion, lef t ant erior subphrenic spac e c ollec t ions may result f rom ext ension of disease proc esses inv olv ing t he lef t perihepat ic spac es or t he lef t post erior subphrenic spac e. T he lef t post er ior subphr enic (per isplenic ) spac e is t he post erior c ont inuat ion of t he ant erior subphrenic spac e (see F ig. 16- 21). Common sourc es of pat hology inv olv ing t he lef t post erior subphrenic spac e inc lude splenic surgery (i.e., post operat iv e absc ess or hemat oma), splenic t rauma, and ext ension of disease proc esses inv olv ing t he ant erior subphrenic spac e. In addit ion, pat hology inv olv ing t he t ail of t he panc reas c an af f ec t t he lef t subphrenic spac e. Unc ommonly , disease proc esses arising in ret roperit oneal organs suc h as t he lef t kidney or lef t adrenal gland c an ext end int o t his perit oneal spac e.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2396

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 15 Abdominal w all neurof ibrosarc oma. Comput ed t omography show s a large c y st ic mass w it hin t he lef t rec t us abdominis musc le in t his pat ient w it h met ast at ic neurof ibrosarc oma.

P.1110

Right Peritoneal Space T he right perit oneal spac e inc ludes bot h t he lesser sac and t he right port ion of t he great er perit oneal spac e surrounding t he liv er (i.e., t he right perihepat ic spac e). T hese t w o spac es c ommunic at e v ia t he epiploic f oramen (f oramen of Winslow ).

Right Perihepatic Space T he right perihepat ic spac e c onsist s of a subphrenic and a subhepat ic spac e (see F igs. 16- 23 and 16- 24), w hic h are part ially separat ed by t he right c oronary ligament s. T he post erior subhepat ic spac e projec t s c ephalad int o t he rec ess bet w een t he liv er and t he right kidney (see F ig. 16- 23B). T his rec ess, know n as t he hepat or enal f ossa or Mor ison's pouc h, is t he most dependent part of t he subhepat ic spac e w hen t he body is in t he supine posit ion and is t heref ore import ant in t he spread and loc alizat ion of int raperit oneal f luid c ollec t ions. Common sourc es of pat hology c ausing f luid c ollec t ions in t he right perihepat ic spac e inc lude t he gallbladder, t he desc ending port ion of t he duodenum (F igs. 16- 25, 16- 26, 16- 27), t he right lobe of t he liv er, and t he right c olon. Anot her import ant c ause of a right perihepat ic f luid c ollec t ion is c ephalad ext ension of pelv ic f luid v ia t he right parac olic gut t er. Oc c asionally , ret roperit oneal disease proc esses arising in t he right kidney , right adrenal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2397

16 - Abdominal Wall and Peritoneal Cavity gland, head of panc reas, or duodenum c an ext end int o t he right perihepat ic spac e.

F igure 16- 16 Met ast at ic c olon c arc inoma. Comput ed t omography demonst rat es t hic kening of t he right abdominal w all musc les (ar r ow heads) w it h loss of t he int ermusc ular f at planes. A disc ret e enhanc ing t umor nodule (ar r ow ) inv olv es t he t ransv ersus abdominis and int ernal oblique musc les.

F igure 16- 17 Renal c ell c arc inoma inv olv ing abdominal w all. A and B: Comput ed t omography show s enhanc ing masses w it hin t he subc ut aneous f at (ar r ow ) and abdominal w all musc les (ar r ow head) in a pat ient w ho underw ent lef t nephrec t omy f or renal c ell c arc inoma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2398

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 18 Malignant asc it es in a w oman w it h met ast at ic ov arian c arc inoma. Ant eriorly t he f alc if orm ligament (ar r ow ) separat es t he right and lef t perit oneal spac es. F at in t he gast roc olic ligament (ar r ow heads) def ines t he lef t margin of t he lef t ant erior perihepat ic spac e. A small amount of f luid is present in t he lesser sac (double ar r ow ). Along t he post erior border of t he spleen, f luid is limit ed medially by t he spleen's perit oneal ref lec t ion (t he bare area of t he spleen) (open ar r ow ).

P.1111

Lesser Sac T he lesser sac c ommunic at es w it h t he remainder of t he right perit oneal spac e t hrough a narrow inlet bet w een t he inf erior v ena c av a and t he f ree margin of t he hepat oduodenal ligament c alled t he epiploic f or am en (or f or am en of Winslow ). In pat ient s w it h int raperit oneal inf lammat ion, t his f oramen may seal, separat ing t he lesser sac f rom t he great er perit oneal c av it y (181). A prominent f old of perit oneum, elev at ed f rom t he post erior abdominal w all by t he lef t gast ric art ery , div ides t he lesser sac int o t w o c ompart ment s—a large lat eral c ompart ment on t he lef t and a smaller medial c ompart ment on t he right (181) (F ig. 16- 28). T he medial c ompart ment c ont ains a superior rec ess t hat w raps around t he c audat e lobe of t he liv er (F ig. 16- 29).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2399

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 19 Biloma.A: A f luid c ollec t ion (B) in t he lef t ant erior perihepat ic spac e c ompresses t he body of t he st omac h (S) and t he lef t lobe of t he liv er (L).B: A more c audal image demonst rat es c ommunic at ion of t he c ollec t ion w it h t he gallbladder f ossa in t his pat ient w ho had undergone rec ent laparosc opic c holec y st ec t omy .

Disease proc esses produc ing generalized asc it es or t hose inv olv ing t he panc reas, t ransv erse c olon, post erior w all of t he st omac h, post erior w all of t he duodenum, and c audat e lobe of t he liv er c an produc e pat hologic c hanges in t he lesser sac . T he most c ommon lesser sac c ollec t ion is asc it es (65). Whereas pat ient s w it h benign, t ransudat iv e P.1112 asc it es t end t o hav e large great er sac c ollec t ions w it h lit t le f luid in t he lesser sac , pat ient s w it h perit oneal c arc inomat osis of t en hav e proport ional f luid v olumes in t he t w o spac es (91). T he largest f luid c ollec t ions t o oc c upy t he lesser sac oc c ur in pat ient s w it h disease proc esses inv olv ing organs direc t ly bordering t his spac e. Alt hough panc reat it ic f luid c ollec t ions loc at ed ant erior t o t he panc reas are generally c onsidered t o be w it hin t he lesser sac , an anat omic st udy has show n t hat suc h c ollec t ions are more likely loc at ed w it hin ret roperit oneal f asc ial planes (193). F luid c ollec t ions inv olv ing t he lat eral c ompart ment of t he lesser sac displac e t he st omac h ant eriorly (see F ig. 1623) and somet imes medially , w hereas medial c ompart ment c ollec t ions may c ause lat eral displac ement of t he st omac h. Collec t ions ext ending below t he lev el of t he panc reat ic body displac e t he t ransv erse c olon and mesoc olon c audally . Less c ommonly , a lesser sac c ollec t ion may ext end v ent ral and c audal t o t he t ransv erse c olon due t o a persist ent inf erior lesser sac rec ess in t he leav es of t he great er oment um (65). Oc c asionally , inf lammat ion or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2400

16 - Abdominal Wall and Peritoneal Cavity neoplasm inv olv ing t he medial c ompart ment may ext end v ia t he aort ic or diaphragmat ic hiat us int o t he low er mediast inum (65).

F igure 16- 20 Pseudomy xoma perit onei. Coronal v olume- rendered image show s dif f use perit oneal inv olv ement w it h c onf luent low at t enuat ion masses, w hic h out line t he small bow el mesent ery (M) and sigmoid mesoc olon (S). Inv olv ement of t he right and lef t subphrenic spac es is show n (ar r ow heads). T he perisplenic spac e (PS) and right perihepat ic spac e (R) are not ed. T he gast rosplenic ligament is seen (ar r ow ).

Inframesocolic Compartment T he inf ramesoc olic c ompart ment is div ided int o t w o unequal spac es by t he obliquely orient ed small bow el mesent ery (F ig. 16- 30). T he smaller right inf ramesoc olic spac e is rest ric t ed inf eriorly by t he junc t ion of t he dist al small bow el mesent ery w it h t he c ec um, w hereas t he larger lef t inf ramesoc olic spac e is open t o t he pelv is inf eriorly exc ept w here it is bounded by t he sigmoid mesoc olon.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2401

16 - Abdominal Wall and Peritoneal Cavity

T he parac olic gut t ers are loc at ed lat eral t o t he at t ac hment s of t he perit oneal ref lec t ions of t he asc ending and desc ending c olon. T he right parac olic gut t er is c ont inuous superiorly w it h t he right perihepat ic spac e. On t he lef t , how ev er, t he phrenic oc olic ligament f orms a part ial barrier bet w een t he lef t parac olic gut t er and t he lef t subphrenic spac e. T he most dependent port ion of t he perit oneal c av it y in bot h t he erec t and supine posit ions is in t he pelv is and c onsist s of lat eral parav esic al spac es and t he midline pouc h of Douglas (rec t ov aginal spac e in w omen, rec t ov esic al spac e in men). T he nat ural f low of int raperit oneal f luid is direc t ed by grav it y and v ariat ions in int raabdominal pressure due t o respirat ion along pat hw ay s det ermined by t he anat omic c ompart ment alizat ion of t he perit oneal c av it y (181) (see F ig. 1630). Absc esses usually f orm and met ast ases usually grow in sit es w here nat ural f low permit s pooling of inf ec t ed f luid or malignant asc it es. T he most c ommon sit es of pooling of inf ec t ed perit oneal f luid and t hus f or absc ess f ormat ion are t he pelv is, right subhepat ic spac e, and right subphrenic spac e (181). Similarly , t he most c ommon sit es f or pooling of malignant asc it es and subsequent f ixat ion and grow t h of perit oneal met ast ases are t he pouc h of Douglas, t he low er small bow el mesent ery near t he ileoc ec al junc t ion, t he sigmoid mesoc olon, and t he right parac olic gut t er (182). F luid in t he inf ramesoc olic c ompart ment rapidly seeks t he pelv is, w here it f irst f ills t he pouc h of Douglas and t hen t he lat eral parav esic al f ossae. F luid in t he right inf rac olic spac e f low s along t he rec esses of t he small bow el mesent ery unt il it pools at t he c onf luenc e of t he mesent ery w it h t he c olon near t he ileoc ec al junc t ion, w it h subsequent ov erf low int o t he pouc h of Douglas. F luid in t he lef t inf rac olic spac e is f requent ly arrest ed by t he sigmoid mesoc olon bef ore desc ending int o t he pelv is. F rom t he pelv is, f luid c an asc end bot h parac olic gut t ers w it h c hanges in int raabdominal pressure during respirat ion. F low along t he lef t parac olic gut t er is slow and w eak, and c ephalad ext ension is usually limit ed by t he phrenic oc olic ligament (187,188). T he major f low is along t he right parac olic gut t er int o t he right subhepat ic spac e, part ic ularly t he post erior ext ension of t his spac e, t he Morison pouc h (187). F rom t he right subhepat ic spac e, f luid may asc end f urt her int o t he right subphrenic spac e. Direc t spread f rom t he right subphrenic spac e ac ross t he midline t o t he lef t subphrenic spac e is prev ent ed by t he f alc if orm ligament .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2402

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 21 Malignant asc it es in a pat ient w it h met ast at ic ov arian c arc inoma.A: Perit oneal f luid out lines t he f alc if orm (ar r ow ) and lef t t riangular (ar r ow heads) ligament s. B: T he lef t perihepat ic spac es (L) are in c ont inuit y w it h t he perisplenic spac e (PS). C : T he gast rohepat ic ligament (open ar r ow ) separat es f luid in t he superior rec ess of t he lesser sac (* ) post eriorly f rom f luid in t he great er perit oneal spac e (G) ant eriorly .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2403

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 22 Asc it es. Comput ed t omography demonst rat es asc it es in t he right (R) and lef t (L) ant erior perihepat ic spac es, separat ed by t he barely perc ept ible f alc if orm ligament (ar r ow head). In t his pat ient , t he lef t ant erior perihepat ic spac e is separat ed f rom t he perisplenic spac e (* ) by t he st omac h (S) and gast roc olic ligament (ar r ow ).

P.1113

Pathology Ascites Asc it es is t he ac c umulat ion of f luid in t he perit oneal c av it y result ing f rom eit her inc reased f luid produc t ion or impaired remov al. T he et iologies of asc it es inc lude c ongest iv e heart f ailure, hy poalbuminemia, c irrhosis, v enous or ly mphat ic obst ruc t ion, inf lammat ion, and neoplasm. CT c an ac c urat ely demonst rat e and loc alize ev en small amount s of f ree perit oneal f luid. Loc alized c ollec t ions of asc it es are f requent ly seen in t he right perihepat ic spac e, t he Morison pouc h, or t he pouc h of Douglas (280). Perit oneal f luid in t he parac olic gut t er is easily dist inguished f rom ret roperit oneal f luid by t he preserv at ion of t he ret roperit oneal f at post erior t o t he asc ending or desc ending c olon (103,130). When a large amount of asc it es is present , t he small bow el loops usually are loc at ed c ent rally w it hin t he abdomen and f luid of t en ac c umulat es in t riangular c onf igurat ions w it hin t he leav es of t he small bow el mesent ery or adjac ent t o bow el loops (253) (F ig. 16- 31). Loc ulat ed asc it es, sec ondary

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2404

16 - Abdominal Wall and Peritoneal Cavity P.1114 t o post operat iv e, inf lammat ory , or neoplast ic adhesions, may appear as a w ell- def ined f luid at t enuat ion mass t hat displac es adjac ent st ruc t ures (F ig. 16- 32). Oc c asionally , perit oneal f luid c ollec t ions c an bec ome loc ulat ed w it hin t he f our normal or ac c essory f issures of t he liv er and c an mimic int rahepat ic c y st s, absc esses, or hemat omas (12). Perit oneal met ast ases in t hese loc at ions also c an be mist aken f or int rahepat ic lesions (F ig. 16- 33) (12).

F igure 16- 23 Malignant asc it es. A andB: Large c ollec t ions of asc it es dist end t he right (R) and lef t (L) port ions of t he great er perit oneal spac e and t he lesser sac (LS), c ompressing t he lef t lobe of t he liv er and t he st omac h (S). T he right perihepat ic spac e is c ont inuous w it h t he right subhepat ic spac e inf eriorly . T he f alc if orm ligament (ar r ow ) and Morison's pouc h (* ) are show n.

F igure 16- 24 A: Coronal T 2- w eight ed magnet ic resonanc e image demonst rat es asc it ic f luid in t he right subphrenic (SP), perihepat ic (R), subhepat ic (SH), lef t subphrenic (L), and perisplenic (PS) spac es.B: A more

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2405

16 - Abdominal Wall and Peritoneal Cavity post erior image show s a small amount of f luid in t he lesser sac (LS). T he gast rosplenic ligament is not ed (ar r ow s).

T he at t enuat ion v alue of asc it ic f luid generally ranges f rom 0 t o 30 HU but may be higher in c ases of exudat iv e asc it es, w it h t he densit y of t he f luid inc reasing w it h inc reasing prot ein c ont ent (36). How ev er, at t enuat ion v alues of asc it ic f luid are nonspec if ic , and inf ec t ed or malignant asc it es c annot reliably be dist inguished f rom unc omplic at ed t ransudat iv e asc it es based on t he at t enuat ion v alue alone. Relat iv ely ac ut e int raperit oneal hemorrhage of t en P.1115 c an be dist inguished f rom ot her f luid c ollec t ions bec ause it result s in perit oneal f luid w it h an at t enuat ion v alue of more t han 30 HU (74). How ev er, ac ut e t raumat ic hemoperit oneum c an c ommonly hav e at t enuat ion v alues of less t han 20 HU and should not be assumed t o be asc it es in t he proper c linic al set t ing (157). Conv ersely , asc it ic f luid may show enhanc ement on delay ed int rav enous c ont rast - enhanc ed CT or MRI (8,55). T his inc rease in t he at t enuat ion v alue of asc it es on delay ed post c ont rast images is a nonspec if ic f inding t hat should not be c onf used w it h high- at t enuat ion f luid result ing f rom hemorrhage or perf orat ion of t he gast roint est inal or urinary t rac t .

F igure 16- 25 Right subphrenic absc ess af t er gast rojejunost omy . A large f luid c ollec t ion w it h an air–f luid lev el (ar r ow ) f ills t he right subphrenic spac e. T he diaphragm (ar r ow heads) separat es t he absc ess f rom a right pleural ef f usion post eriorly . At elec t at ic lung (c ur v ed ar r ow ) is show n.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2406

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 26 Absc ess in right perihepat ic spac e sec ondary t o perf orat ed duodenal ulc er. A near- w at er- densit y c ollec t ion (A) w it h an air–f luid lev el (ar r ow head) in t he right perihepat ic (subphrenic ) spac e is limit ed post eriorly by t he bare area of t he liv er (ar r ow s).

F igure 16- 27 Perf orat ed duodenal ulc er. F luid, air, and high- densit y oral c ont rast mat erial (* ) f ill t he right perihepat ic spac e. Air and oral c ont rast mat erial are also ident if ied in t he lef t perit oneal spac e (* * ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2407

16 - Abdominal Wall and Peritoneal Cavity T he dist ribut ion of asc it ic f luid in t he perit oneal c av it y may suggest t he nat ure of t he f luid. Pat ient s w it h benign P.1116

t ransudat iv e asc it es t end t o hav e large great er sac c ollec t ions w it h lit t le f luid in t he lesser sac , w hereas pat ient s w it h malignant asc it es of t en hav e proport ional v olumes of f luid in t hese perit oneal spac es (50) (see F ig. 16- 23). Large lesser sac c ollec t ions may be seen in pat ient s w it h disease proc esses in organs t hat border t his spac e (91). How ev er, t hese CT f eat ures are not spec if ic and needle aspirat ion may be nec essary t o dif f erent iat e t ransudat iv e f rom exudat iv e asc it es.

F igure 16- 28 Asc it es in t he lesser sac . T he lat eral (L) and medial (M) c ompart ment s of t he lesser sac are div ided by a f old of perit oneum t hrough w hic h passes t he lef t gast ric art ery (ar r ow head). Asc it es is also present in t he lef t and right great er perit oneal spac es.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2408

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 29 Met ast at ic ov arian c arc inoma. Malignant asc it es f ills t he medial (M) and lat eral (L) c ompart ment s of t he lesser sac . T he superior rec ess of t he medial c ompart ment w raps around t he c audat e lobe of t he liv er (C). Perihepat ic serosal met ast at ic implant s (ar r ow heads) are present .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2409

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 30 Sc hemat ic diagram of t he inf ramesoc olic c ompart ment of t he perit oneal c av it y . T he small bow el mesent ery div ides t he inf ramesoc olic c ompart ment int o t w o unequal spac es. T he arrow s indic at e t he nat ural f low of asc it es w it hin t he perit oneal c av it y . Right inf rac olic spac e (RIS); lef t inf rac olic spac e (LIS); asc ending c olon (AC); and desc ending c olon (DC) are marked.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2410

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 31 Massiv e asc it es. T he small bow el loops are loc at ed c ent rally w it hin t he abdomen. T he pleat ed nat ure of t he small bow el mesent ery c an be apprec iat ed as f luid out lines sev eral of t he mesent eric leav es. F luid ac c umulat ing bet w een leav es of t he mesent ery t akes on a t riangular c onf igurat ion (ar r ow heads). Not e t hat t he ret roperit oneal f at post erior t o t he asc ending (A) and desc ending (D) c olon is preserv ed.

F igure 16- 32 Ov arian c arc inoma. A met ast at ic implant (m) on t he f alc if orm ligament separat es malignant asc it es in t he right perihepat ic (R) and lef t ant erior (LA) perihepat ic spac es. T he right perihepat ic f luid is loc ulat ed and def orms t he liv er margin. T he gast rohepat ic ligament (ar r ow heads) separat es asc it es in t he lef t post erior perihepat ic spac e (LP) and t he medial c ompart ment of t he lesser sac (LS).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2411

16 - Abdominal Wall and Peritoneal Cavity P.1117 MRI also c an be used t o ev aluat e int raabdominal f luid c ollec t ions. A rec ommended t ec hnique f or perit oneal imaging is a breat h- hold gadoliniumenhanc ed, T 1- w eight ed gradient ec ho ac quisit ion w it h f at suppression, obt ained af t er administ rat ion of a large v olume of dilut e oral barium. Immediat e and delay ed post c ont rast images are ac quired, af t er ac quiring T 2w eight ed images (168). T ransudat iv e asc it es appears low in signal int ensit y on T 1- w eight ed images

and high in signal int ensit y on T 2- w eight ed images bec ause of it s long T 1 and T 2 relaxat ion (50,309) (F ig. 16- 34). T he T 1 relaxat ion of f luid c ollec t ions dec reases w it h inc reasing prot ein c onc ent rat ion (294). T hus exudat iv e f luid c ollec t ions demonst rat e int ermediat e t o short T 1 and long T 2 v alues. Bot h t ransudat iv e and exudat iv e f luid c ollec t ions are w ell seen on c ont rast enhanc ed T 1- w eight ed images w here t hey appear low in signal int ensit y and on T 2- w eight ed images w here t hey appear high in signal int ensit y . Delay ed enhanc ement of asc it ic f luid on images obt ained 15 t o 20 minut es af t er gadolinium c helat e administ rat ion is indic at iv e of an exudat iv e asc it ic f luid c ollec t ion (8).

F igure 16- 33 Perit oneal met ast ases simulat ing int rahepat ic masses. A: Comput ed t omography show s a low at t enuat ion perit oneal mass (ar r ow ) w it hin t he f issure f or t he ligament um v enosum in a pat ient w it h c olon c arc inoma. B: T 2- w eight ed magnet ic resonanc e imaging demonst rat es a hy perint ense mass (ar r ow ) w it hin t he f issure f or t he ligament um t eres in a pat ient w it h appendic eal c arc inoma.

Intraperitoneal Abscess

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2412

16 - Abdominal Wall and Peritoneal Cavity

T he epidemiology of int raabdominal absc ess has c hanged in rec ent dec ades. In t he f irst half of t he 20t h c ent ury , perf orat ed ulc er, appendic it is, and biliary t rac t disease w ere t he most c ommon c auses (72,211). How ev er, during t he past sev eral dec ades, int raabdominal absc ess has oc c urred most c ommonly af t er surgery , part ic ularly surgery inv olv ing t he st omac h, biliary t rac t , and c olon (104,256,267,310). Despit e adv anc es in surgic al t ec hnique and ant imic robial t herapy , int raabdominal absc ess remains a serious diagnost ic and t herapeut ic problem. Ev en w it h t reat ment , mort alit y rat es c an reac h 30% (229). Alt hough most pat ient s present w it h f ev er, leukoc y t osis, and abdominal pain, pat ient s w it h c hronic , w alled- of f absc esses may present w it h f ew ov ert c linic al signs or sy mpt oms. F urt hermore, some sy mpt oms may be masked by t he administ rat ion of ant ibiot ic s or c ort ic ost eroids (8). CT is t he most ac c urat e single imaging t est f or diagnosing int ra- abdominal absc ess (64). When examining a pat ient f or a suspec t ed absc ess, c aref ul at t ent ion t o t ec hnique is c ruc ial f or c orrec t diagnosis. T he ent ire abdomen f rom t he diaphragm t o t he pubic sy mphy sis should be sc anned and adequat e oral c ont rast mat erial should be administ ered. Alt hough a neut ral c ont rast agent (w at er, met hy lc ellulose or v ery low at t enuat ion v alue barium solut ion) is P.1118 usef ul f or most abdominal and pelv ic mult i- det ec t or CT applic at ions, a w at ersoluble posit iv e oral c ont rast agent (iodine solut ion) is pref erable w hen an absc ess is suspec t ed t o av oid mist aking a f luid- f illed bow el loop f or an absc ess, or v ic e v ersa.

F igure 16- 34 Asc it es. Bec ause of it s long T 1 and T 2 relaxat ion, asc it es appears low in signal int ensit y on T 1- w eight ed (A) and high in signal int ensit y

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2413

16 - Abdominal Wall and Peritoneal Cavity on T 2- w eight ed (B) magnet ic resonanc e images. F alc if orm ligament (ar r ow ) and right t riangular ligament (ar r ow head) are not ed.

T he CT appearanc e of an absc ess is v ariable depending on it s age and loc at ion. In it s earliest st age, an absc ess c onsist s of a f oc al ac c umulat ion of neut rophils in a t issue or organ seeded by bac t eria and t hus appears as a mass w it h an at t enuat ion v alue near t hat of sof t t issue. As t he absc ess mat ures, it undergoes liquef ac t iv e nec rosis. At t he same t ime, highly v asc ularized c onnec t iv e t issue prolif erat es at t he periphery of t he nec rot ic region. At t his st age, t he absc ess has a c ent ral region of near- w at er at t enuat ion surrounded by a higher at t enuat ion rim t hat usually enhanc es af t er administ rat ion of int rav enous c ont rast mat erial (10) (F ig. 16- 35). Approximat ely one t hird of absc esses c ont ain v ariable amount s of gas, appearing on CT as eit her mult iple small bubbles or a gas–f luid lev el (10,37,103,128,148,319) (F igs. 16- 36 and 16- 37). T he presenc e of a long gas–f luid lev el suggest s c ommunic at ion w it h t he gast roint est inal t rac t (128). Post operat iv e pac king mat erials used f or hemost asis, suc h as oxidized c ellulose (Surgic el) and gelat in bioabsorbable sponge, c an mimic a gasc ont aining absc ess. F indings t hat may help dif f erent iat e a hemost at ic agent f rom an absc ess are a linear arrangement of t ight ly pac ked gas bubbles, an unc hanged appearanc e on subsequent examinat ions, and lac k of eit her a gas–f luid lev el or an enhanc ing w all (257,327). Anc illary f indings of an absc ess inc lude displac ement of surrounding st ruc t ures, t hic kening or oblit erat ion of adjac ent f asc ial planes, and inc reased densit y of adjac ent mesent eric f at . Whereas most absc esses are round or ov al in shape, t hose adjac ent t o solid organs, suc h as t he liv er, may hav e a c resc ent ic or lent ic ular c onf igurat ion. In some c ases, t he CT appearanc e of an absc ess c an suggest it s et iology . A low - densit y right low er quadrant mass c ont aining a round c alc if ic densit y is highly suggest iv e of P.1119 an appendic eal absc ess w it h an appendic olit h. Elsew here in t he abdomen, a low - densit y mass c ont aining a high- densit y objec t suggest s a f oreign body absc ess. One of t he more c ommon c auses of a f oreign body absc ess is a ret ained surgic al sponge (c alled a gossy pibom a) (269) (F ig. 16- 38).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2414

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 35 Pelv ic absc ess. Comput ed t omography in a post operat iv e pat ient show s a loc ulat ed f luid c ollec t ion (A) w it h an enhanc ing rim.

F igure 16- 36 Pelv ic absc ess sec ondary t o ac ut e div ert ic ulit is. Comput ed t omography show s a gas c ont aining f luid c ollec t ion (A) w it h rim enhanc ement .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2415

16 - Abdominal Wall and Peritoneal Cavity Alt hough t he CT f indings prev iously disc ussed are highly suggest iv e of absc ess, t hey are not spec if ic . Ot her masses t hat c an hav e a c ent ral low at t enuat ion v alue inc lude a c y st , pseudoc y st , hemat oma, urinoma, ly mphoc ele, biloma, loc ulat ed asc it es, t hrombosed aneury sm, and nec rot ic neoplasm. In addit ion, normal st ruc t ures suc h as unopac if ied bladder, st omac h, and bow el c an mimic t he appearanc e of an absc ess (F ig. 16- 39).

T hic kening of adjac ent f asc ial planes is also nonspec if ic and c an be seen w it h int raabdominal hemat oma and neoplast ic inf ilt rat ion. Ev en t he presenc e of gas w it hin a mass is nonspec if ic f or absc ess bec ause a nec rot ic noninf ec t ed neoplasm and a mass t hat c ommunic at es w it h bow el c an also c ont ain gas. Bec ause a spec if ic diagnosis of absc ess based on CT f indings alone is not possible, c orrelat ion w it h c linic al hist ory is import ant . Perc ut aneous needle aspirat ion may be nec essary t o make a def init iv e diagnosis. In t his regard, CT c an be v ery helpf ul in ident if y ing a plane of ac c ess f or aspirat ion t hat is bot h saf e and f ree of c ont aminat ion f rom bow el. T he presenc e or absenc e of an absc ess c an be est ablished by obt aining a spec imen f or Gram st ain and c ult ure. In most inst anc es, if an absc ess is present , a c at het er c an be insert ed perc ut aneously f or def init iv e drainage (279,303). Perc ut aneous absc ess drainage has prov en t o be a saf e and ef f ec t iv e approac h t o t he diagnosis and t reat ment of int raabdominal absc ess (259,302). Alt hough it w as originally t hought t hat only w ell- def ined, uniloc ular absc esses w it h saf e drainage rout es should be drained perc ut aneously , t he c rit eria f or perc ut aneous drainage hav e been expanded t o inc lude ill- def ined and mult isept at ed absc esses, as w ell as t hose c ommunic at ing w it h t he gast roint est inal t rac t or loc at ed deep t o major abdominal organs (83,196). Ev en pot ent ially c omplic at ed absc esses suc h as appendic eal, div ert ic ular, and int erloop absc esses sec ondary t o Crohn disease c an be drained w it hout c omplic at ions (20,131,202,208,255,304). In t he P.1120 c ase of periappendic eal absc esses, perc ut aneous drainage may c omplet ely eliminat e t he need f or surgery (20,131,207,304), w hereas perc ut aneous drainage of div ert ic ular absc esses of t en c onv ert s c omplex t w o- or t hree- st age surgic al proc edures t o saf er one- st age c olonic resec t ions (202). T w o absc ess c harac t erist ic s hav e been f ound t o be v aluable in predic t ing t he ev ent ual out c ome of perc ut aneous drainage: t he loc at ion of t he absc ess and t he dist ribut ion of gas w it hin t he f luid c ollec t ion. Subphrenic and hepat ic absc esses are more likely t o hav e a suc c essf ul out c ome t han t hose in ot her

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2416

16 - Abdominal Wall and Peritoneal Cavity

loc at ions (128). In addit ion, absc esses w it h superf ic ial gas (superf ic ial bubbles or a gas- f luid lev el) are more likely t o be drained c omplet ely t han t hose w it h deep gas bubbles (96% v ersus 62%) (118). Bec ause no spec if ic CT f eat ure of an absc ess predic t s t hat it c annot be drained suc c essf ully , all int raabdominal absc esses should be c onsidered c andidat es f or perc ut aneous drainage (83,128). T he t ec hnic al det ails of CT - guided absc ess drainage are desc ribed in Chapt er 3.

F igure 16- 37 Perit oneal absc ess.A: Cont rast - enhanc ed c omput ed t omography show s a large f luid c ollec t ion (A) w it h a gas–f luid lev el and deeper f oc i of gas inv olv ing t he lef t ant erior perihepat ic spac e.B: T he absc ess (A) ext ends int o t he pelv is, and a smaller gas- c ont aining absc ess (a) is seen in t he right side of t he pelv is.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2417

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 38 Gossy piboma. T ransaxial c omput ed t omography show s sev eral high densit y f oc i w it hin t w o large w alled- of f masses of mot t led gas and sof t t issue densit y (G) c orresponding t o t he inf lammat ory reac t ion in t his pat ient w ho had f iv e ret ained surgic al sponges f rom a rec ent laparot omy .

F igure 16- 39 F luid- f illed c ec um simulat ing an absc ess. A: Init ial c omput ed t omography examinat ion demonst rat es a low - at t enuat ion pelv ic mass (M) w it h mult iple gas bubbles simulat ing an absc ess. B: F ollow - up examinat ion 1 day lat er demonst rat es marked c hange in appearanc e of t he now less- dist ended c ec um c ont aining st ool and oral c ont rast mat erial.

T he MRI appearanc e of int raabdominal absc ess is also nonspec if ic . T heref ore, MRI does not eliminat e t he need f or aspirat ion in est ablishing a diagnosis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2418

16 - Abdominal Wall and Peritoneal Cavity Bec ause of it s int ermediat e T 1 and long T 2, an absc ess demonst rat es low t o int ermediat e signal int ensit y on T 1- w eight ed images and homogeneous or het erogeneous high signal int ensit y on T 2- w eight ed images (204,261). It is usually best demonst rat ed on gadolinium- enhanc ed T 1- w eight ed f at suppressed images as a w ell def ined f luid c ollec t ion w it h peripheral rim enhanc ement and enhanc ement of adjac ent t issues (204,261). In a st udy of perc ut aneously obt ained normal and abnormal body f luids, t he mean T 1 v alue of absc ess c ont ent s w as f ound t o be signif ic ant ly short er and t he mean T 2 v alue signif ic ant ly longer t han t hose of bile, asc it ic f luid, urine c ollec t ions, c y st s and pseudoc y st f luid, and pleural f luid (32). T he ac c urac y of CT and MRI in det ec t ing int raabdominal absc ess is approximat ely 95% (10,100,103,147,148,149,150,204,260,319). Most f alse–posit iv e diagnoses are a result of mist aking unopac if ied f luid- f illed st omac h, bow el, or bladder f or an absc ess or mist aking a st erile f luid

c ollec t ion f or an absc ess. If a quest ion exist s as t o t he nat ure of a f luid- f illed st ruc t ure, addit ional oral, rec t al, P.1121 or int rav enous c ont rast mat erial c an be administ ered and a limit ed resc an perf ormed (F ig. 16- 40).

F igure 16- 40 Cul- de- sac absc ess af t er c holec y st ec t omy . A: A small f luid c ollec t ion (ar r ow ) w it h enhanc ing rim is dif f ic ult t o dist inguish f rom unopac if ied adjac ent rec t um and sigmoid c olon. B: Af t er administ rat ion of rec t al c ont rast mat erial, t he absc ess (A) is easily dist inguishable f rom t he now opac if ied rec t um (R) and sigmoid c olon (S).

Other Intraperitoneal Fluid Collections

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2419

16 - Abdominal Wall and Peritoneal Cavity Int raperit oneal hemorrhage may result f rom ov er- ant ic oagulat ion; bleeding

diat hesis; t rauma t o t he liv er, spleen, or mesent ery ; spont aneous rupt ure of a v asc ular neoplasm; hemorrhagic c y st or ec t opic pregnanc y ; perf orat ion of a duodenal ulc er; or ac ut e mesent eric isc hemia. In addit ion, int raperit oneal blood is f requent ly seen af t er abdominal surgery . CT has been show n t o be highly sensit iv e and spec if ic f or diagnosing hemoperit oneum (74), w it h t he diagnosis being based on t he high at t enuat ion v alue of t he perit oneal f luid (F igs. 16- 41 and 16- 42). How ev er, it is import ant t o keep in mind t hat ac ut e hemoperit oneum c an hav e at t enuat ion v alues of less t han 20 HU (157). T he CT appearanc e of int raperit oneal hemorrhage depends on t he loc at ion, age, and ext ent of t he bleeding. Immediat ely af t er hemorrhage, int raperit oneal blood has t he same at t enuat ion as c irc ulat ing blood. Wit hin hours, how ev er, t he at t enuat ion inc reases as hemoglobin is c onc ent rat ed during c lot f ormat ion (203,205). In most c ases, t he at t enuat ion begins t o dec rease w it hin sev eral day s as c lot ly sis t akes plac e (24). T he at t enuat ion v alue dec reases st eadily w it h t ime and of t en approac hes t hat of w at er (0 t o 20 HU) af t er 2 t o 4 w eeks (150). During t he hy perdense phase, t he at t enuat ion v alue of int raperit oneal blood ranges f rom 20 t o 90 HU (74,161,289,318). In one large st udy , all pat ient s w it h a less t han 48- hour hist ory of hemoperit oneum had f luid c ollec t ions c ont aining areas of at t enuat ion more t han 30 HU (74). T he morphologic c harac t erist ic s of rec ent int raperit oneal hemorrhage are v ariable. T he f luid c ollec t ion may be homogeneously hy perdense or may be het erogeneous w it h nodular or linear areas of high at t enuat ion surrounded by low er at t enuat ion f luid. T he het erogeneit y may result f rom irregular c lot resorpt ion or int ermit t ent bleeding (318). In most c ases, int raperit oneal blood c ont ains f oc al areas of c lot t hat are higher in at t enuat ion t han t he f ree int raperit oneal blood (see F ig. 16- 42). T hese loc alized c lot s are helpf ul in det ermining t he bleeding sit e bec ause t hey usually f orm adjac ent t o t he organ f rom w hic h t he hemorrhage originat ed (74). Oc c asionally , f resh blood w it hin a hemat oma or c onf ined w it hin a P.1122 perit oneal spac e may show a hemat oc rit ef f ec t w it h sediment ed ery t hroc y t es produc ing a dependent lay er of high at t enuat ion (F ig. 16- 43). T he most c ommon sit e of blood ac c umulat ion on CT af t er upper abdominal t rauma is Morison's pouc h (74,173). T he right parac olic gut t er is anot her c ommon sit e of blood c ollec t ion, ev en in c ases of splenic t rauma. Wit h ext ensiv e hemorrhage, large c ollec t ions of blood may f ill t he pelv is w it h lit t le blood in upper abdominal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2420

16 - Abdominal Wall and Peritoneal Cavity sit es. T heref ore, it is import ant t o inc lude t he pelv is in any CT examinat ion perf ormed f or suspec t ed int raabdominal hemorrhage, part ic ularly in pat ient s w ho hav e sust ained blunt abdominal t rauma (74). Bef ore beginning t he

examinat ion, adequat e oral c ont rast mat erial should be administ ered t o opac if y all abdominal and pelv ic bow el loops.

F igure 16- 41 Hemoperit oneum. High at t enuat ion f luid (H) inv olv es t he gast rosplenic ligament in a pat ient w ho had undergone a Nissen f undoplic at ion.

F igure 16- 42 Hemoperit oneum. Het erogeneous high at t enuat ion f luid (H) dist ends t he subhepat ic port ion of t he right perit oneal spac e in a pat ient w ho had a hepat ic injury .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2421

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 43 Int raperit oneal hemat oma in an ant ic oagulat ed pat ient . Unenhanc ed c omput ed t omography examinat ion demonst rat es a large f luid c ollec t ion c ont aining a hemat oc rit lev el (ar r ow ) w it h higher at t enuat ion ery t hroc y t es lay ering dependent ly .

If a CT examinat ion w it hout int rav enous c ont rast mat erial has been obt ained, v iew ing t he images w it h a narrow w indow w idt h is helpf ul t o ac c ent uat e t he densit y dif f erenc e bet w een t he f resh blood and t he adjac ent sof t t issues. In most c ases how ev er, a prec ont rast CT examinat ion is unnec essary and one c an begin t he st udy w it h int rav enous c ont rast mat erial administ ered as a bolus. T he c ont rast enhanc ement helps t o demonst rat e injuries t o t he liv er, spleen, and kidney s and makes int raperit oneal f luid c ollec t ions more apparent by inc reasing t he densit y of t he surrounding t issues. Ext rav asat ion of int rav enous c ont rast mat erial, result ing in an area of f luid w it h an at t enuat ion higher t han t he remainder of t he ac ut e hemoperit oneum, is an indic at or of signif ic ant ac t iv e bleeding (277). MRI also c an be used t o demonst rat e int raperit oneal hemorrhage. How ev er, many pat ient s ref erred f or suspec t ed int raabdominal hemorrhage are unst able and require ext ensiv e monit oring and support iv e equipment , making MRI less prac t ic al. A hemat oma less t han 48 hours old may hav e a nonspec if ic signal int ensit y (297). Int raabdominal hemat oma more t han 3 w eeks old c an hav e a spec if ic appearanc e, ref erred t o as t he c onc ent r ic r ing sign, in w hic h a t hin

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2422

16 - Abdominal Wall and Peritoneal Cavity peripheral rim t hat is dark on all sequenc es surrounds a bright inner ring t hat is most dist inc t iv e on T 1- w eight ed images (102). A hemat oc rit ef f ec t

oc c asionally c an be seen on MRI also. On T 1- w eight ed images, t he dependent port ion of t he hemorrhagic c ollec t ion is hy perint ense c ompared w it h t he supernat ant , w hereas on T 2- w eight ed images t he signal int ensit y relat ionship is rev ersed (F ig. 16- 44).

F igure 16- 44 Hemoperit oneum. T 2- w eight ed magnet ic resonanc e image w it h f at suppression show s a large right perihepat ic spac e f luid c ollec t ion w it h a hemat oc rit lev el (ar r ow ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2423

16 - Abdominal Wall and Peritoneal Cavity F igure 16- 45 Biloma. Comput ed t omography show s int raperit oneal bile c ollec t ions loc ulat ed in t he right perihepat ic spac e in t his pat ient w ho had undergone laparosc opic c holec y st ec t omy .

P.1123 Int raperit oneal bile ac c umulat ion (biloma) is c aused by iat rogenic , t raumat ic , or spont aneous rupt ure of t he biliary t rac t (F ig. 16- 45) (305). T he bile elic it s a low - grade inf lammat ory response t hat generally w alls of f t he c ollec t ion by t he f ormat ion of a t hin c apsule or inf lammat ory adhesions w it hin t he mesent ery and oment um (165,305). Most bilomas appear round or ov al and hav e at t enuat ion v alues of less t han 20 HU. T hose c omplic at ed by hemorrhage or inf ec t ion may be higher in densit y . Bilomas are usually c onf ined t o t he upper abdomen. Alt hough most are loc at ed in t he right upper quadrant , lef t upper quadrant bilomas are not unc ommon, oc c urring in approximat ely 30% of c ases (see F ig. 16- 19) (197,305). Bec ause t he CT appearanc e is not spec if ic , biloma c annot be dist inguished f rom ot her abdominal f luid c ollec t ions and eit her needle aspirat ion or hepat obiliary sc int igraphy is usually required t o est ablish t he diagnosis. Most bilomas c an be t reat ed suc c essf ully w it h perc ut aneous c at het er drainage (197,305). Int raabdominal c ollec t ions of urine may result f rom urinary t rac t obst ruc t ion or f rom surgery or t rauma inv olv ing t he kidney , uret er, or bladder. F ree int raperit oneal urine usually result s f rom t raumat ic rupt ure of t he bladder dome. CT examinat ion of pat ient s w it h int raperit oneal bladder rupt ure perf ormed af t er c y st ography or int rav enous c ont rast mat erial administ rat ion show s high- densit y f luid f reely f illing t he perit oneal spac es. Alt hough loc alized c ollec t ions of urine (urinomas) usually oc c ur w it hin t he ret roperit oneal spac e, an int raperit oneal urinoma c an oc c ur if t he anat omic boundaries of t he ret roperit oneum hav e been disrupt ed by t rauma or prior surgery (112). On CT images obt ained w it hout int rav enous c ont rast mat erial, t he at t enuat ion v alue of a urinoma is less t han 20 HU. Af t er administ rat ion of int rav enous c ont rast medium, how ev er, t he at t enuat ion v alue c an inc rease as a result of ac c umulat ion of opac if ied urine in t he f luid c ollec t ion. T hus, delay ed CT imaging may be helpf ul in est ablishing t he diagnosis of urinoma. Ly mphoc eles are abnormal ac c umulat ions of ly mphat ic f luid usually result ing f rom operat iv e disrupt ion of ly mphat ic v essels. T he most c ommon proc edures t o c ause ly mphoc eles are renal t ransplant at ion and ret roperit oneal ly mph node dissec t ion. Alt hough most ly mphoc eles are c onf ined t o t he ret roperit oneum, int raperit oneal ly mphoc eles do oc c ur. T he more c ommon manif est at ion of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2424

16 - Abdominal Wall and Peritoneal Cavity int raperit oneal ly mph leakage is c hy lous asc it es, usually result ing f rom ly mphat ic obst ruc t ion by t umor (232). A ly mphoc ele has a nonspec if ic

appearanc e and c annot be dist inguished f rom ot her abdominal f luid c ollec t ions by it s CT or MRI f eat ures alone. T he diagnosis c an be est ablished by perc ut aneous aspirat ion (232,313). Chy lous asc it es usually is indist inguishable f rom ot her t y pes of asc it ic f luid. Oc c asionally , how ev er, t he diagnosis may be suggest ed if negat iv e Hounsf ield numbers, c aused by t he high f at c ont ent of ly mph, are det ec t ed. T he rare f inding of a f at –f luid lev el in asc it ic f luid is pat hognomonic of c hy lous asc it es (114).

THE MESENTERIES AND GREATER OMENTUM Anatomy T he small bow el mesent ery is a broad, f an- shaped f old of perit oneum t hat c onnec t s t he jejunum and ileum t o t he post erior abdominal w all (93). It originat es at t he duodenojejunal f lexure just t o t he lef t of t he spine and ext ends obliquely t o t he ileoc ec al junc t ion. T he root of t he small bow el mesent ery is c ont iguous superiorly w it h t he hepat oduodenal ligament , ant eriorly w it h t he t ransv erse mesoc olon, and post erolat erally w it h t he asc ending and desc ending mesoc olons (212). Wit hin t he t w o f used lay ers of t he small bow el mesent ery are c ont ained t he int est inal branc hes of t he superior mesent eric art ery and v ein, ly mphat ic v essels, ly mph nodes, nerv es, and v ariable amount s of f at . On CT , t he mesent ery appears as a f at c ont aining area c ent ral t o t he small bow el loops w it hin w hic h t he jejunal and ileal v essels c an be ident if ied as dist inc t , round, or linear densit ies (273). Normal ly mph nodes less t han 1 c m in diamet er usually c an be ident if ied, part ic ularly w it h mult idet ec t or row CT (170). T he normal mesent eric f at is similar in at t enuat ion t o t he subc ut aneous f at (- 100 t o - 160 HU) (272). In pat ient s w it h a large amount of asc it es, t he pleat ed nat ure of t he mesent ery c an be apprec iat ed as f luid out lines t he mesent eric f olds. T he t ransv erse mesoc olon, w hic h ext ends f rom t he ant erior surf ac e of t he panc reas t o t he t ransv erse c olon, c ont ains t he middle c olic art eries and v eins. On t he right , t he root of t he mesoc olon is c ont inuous w it h t he duodenoc olic ligament and t hus t he post erior aspec t of t he hepat ic f lexure. Medially it c rosses t he desc ending duodenum and head of panc reas ext ending along t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2425

16 - Abdominal Wall and Peritoneal Cavity low er ant erior edge of t he body and t ail of t he panc reas. On t he lef t it is c ont inuous P.1124 w it h t he phrenic oc olic and splenorenal ligament s (185). In most pat ient s, t he t ransv erse mesoc olon is readily ident if ied on CT as a f at - c ont aining area

ext ending f rom t he panc reas, part ic ularly at t he lev el of t he unc inat e proc ess, t o t he margin of t he c olonic w all (133). In t hin pat ient s, t he t ransv erse mesoc olon may be dif f ic ult t o ident if y bec ause of t he lac k of mesent eric f at and t he st eeply oblique orient at ion of t he mesent ery in suc h pat ient s. Nev ert heless, t he middle c olic branc hes of t he t ransv erse mesoc olon c an be ident if ied in nearly all pat ient s (273). T he root of t he small bow el mesent ery at it s origin near t he duodenojejunal f lexure is c ont inuous w it h t he root of t he t ransv erse mesoc olon (182). T he sigmoid mesoc olon, ext ending f rom t he post erior pelv ic w all and c ont aining t he sigmoid and hemorrhoidal v essels, c an usually be ident if ied deep w it hin t he pelv is. T he great er oment um c onsist s of a double lay er of perit oneum t hat ext ends inf eriorly f rom t he great er c urv at ure of t he st omac h, t urns superiorly on it self draping ov er t he t ransv erse c olon, and ext ends t o t he panc reas w it hin t he ret roperit oneum (278). T he v asc ular supply t o t he great er oment um is largely t hrough t he right and lef t gast roepiploic art eries. On CT and MRI, t he great er oment um appears as a band of f at t y t issue of v ariable t hic kness just deep t o t he ant erior perit oneal f asc ia, ext ending f rom t he ant rum of t he st omac h superiorly t o t he pelv is inf eriorly . It c ont ains small v essels and is loc at ed just ant erior t o t he t ransv erse c olon and t he small bow el loops of t he low er abdomen.

Pathology of the Mesenteries, Omentum, and Peritoneum Mesent eric abnormalit ies are readily ident if ied on CT in all but t he leanest pat ient s bec ause of t he abundanc e of f at present w it hin t he normal mesent ery . Various pat hologic proc esses, bot h benign and malignant , may inf ilt rat e t he mesent ery c ausing an inc rease in at t enuat ion of t he mesent eric f at , dist ort ion of t he mesent eric arc hit ec t ure, and loss of def init ion of t he mesent eric v essels (191). Some of t hese proc esses may also c ause t hic kening of t he perit oneal lining. Det ec t ion of mesent eric abnormalit ies requires rigorous

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2426

16 - Abdominal Wall and Peritoneal Cavity at t ent ion t o CT t ec hnique. It is part ic ularly import ant t o opac if y t he gast roint est inal t rac t w it h oral c ont rast mat erial so t hat unopac if ed bow el is not mist aken f or a mesent eric mass. Conv ersely , a small mesent eric mass c an be obsc ured if surrounded by unopac if ied bow el loops. At least 500 mL of an

oral c ont rast agent should be giv en 30 t o 45 minut es prior t o t he examinat ion t o opac if y t he dist al small bow el. Anot her 500 mL of c ont rast mat erial should be giv en 15 minut es bef ore t he examinat ion t o opac if y t he st omac h and proximal small bow el. If bow el c annot c onf ident ly be dist inguished f rom a mesent eric mass, addit ional images t hrough t he suspic ious area c an be ac quired af t er addit ional oral c ont rast mat erial has been administ ered or af t er delay allow s t ransit of more proximal c ont rast mat erial. Oc c asionally , it is helpf ul t o opac if y t he c olon per rec t um w it h a dilut e c ont rast solut ion or air t o dif f erent iat e a redundant sigmoid c olon f rom a pelv ic mass. MRI also c an be used t o det ec t , c harac t erize, and delineat e mesent eric abnormalit ies. T 1- w eight ed gradient - ec ho images w it h f at suppression af t er int rav enous gadolinium- c helat e administ rat ion demonst rat e mesent eric pat hology w ell. Bec ause of t he longer image ac quisit ion t ime of MRI, perist alt ic and respirat ory mot ion art if ac t s somet imes degrade MR images and limit spat ial resolut ion in t he region of t he mesent ery . Administ rat ion of a hy pot onic bow el agent , suc h as gluc agon int ramusc ularly or subc ut aneously , c an help limit perist alt ic mot ion. As w it h CT , opac if ic at ion of t he abdominal and pelv ic bow el loops is import ant w hen ev aluat ing t he abdominal mesent eries w it h MRI. A large v olume of a dilut e oral barium solut ion is usef ul f or t his purpose (166,167).

Edema Dif f use mesent eric edema is most c ommonly t he result of hy poalbuminemia, usually c aused by c irrhosis (45,296). T he nephrot ic sy ndrome, heart f ailure, mesent eric isc hemia, v asc ulit is and mesent eric v enous or ly mphat ic obst ruc t ion are less c ommon c auses. T he CT f indings c harac t erist ic of mesent eric edema inc lude inc reased densit y of t he mesent eric f at , poor def init ion of segment al mesent eric v essels, and relat iv e sparing of t he ret roperit oneal f at (191,272). Mesent eric edema sec ondary t o a sy st emic disease of t en c oexist s w it h subc ut aneous edema and asc it es (212). Bow el w all t hic kening also is present in some pat ient s. Whenev er mesent eric edema is ident if ied, t he root of t he mesent ery should be c aref ully ev aluat ed t o exc lude a f oc al t umor mass obst ruc t ing mesent eric v essels and c reat ing sec ondary

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2427

16 - Abdominal Wall and Peritoneal Cavity edema (272). Alt hough dif f use inf ilt rat ion of t he mesent ery by met ast at ic t umor may hav e an appearanc e similar t o t hat of mesent eric edema, it c an somet imes be dist inguished f rom edema by t he rigidit y of t he mesent eric

leav es. Imaging w it h t he pat ient in t he lat eral dec ubit us or prone posit ion may be helpf ul in demonst rat ing t he mesent eric f ixat ion.

Pancreatitis CT has est ablished roles in t he init ial diagnosis, assessment of prognosis, ev aluat ion of c omplic at ions, direc t ion of image- guided int erv ent ion, and f ollow - up of panc reat it is (16,19). T he t ransv erse mesoc olon c an be af f ec t ed by dissec t ion of panc reat ic enzy mes in pat ient s w it h sev ere ac ut e panc reat it is (180,274). In pat ient s w it h f ulminant panc reat it is, t he mesoc olon is inv olv ed in approximat ely one t hird of c ases (133). T he small bow el mesent ery is inv olv ed muc h less c ommonly . T he main CT f inding in pat ient s w it h mesent eric inf lammat ion relat ed t o panc reat it is is st reaky or c onf luent inc reased densit y of t he mesent eric f at . MRI may demonst rat e low signal int ensit y mesent eric st randing on T 1- w eight ed images and eit her normal or high signal int ensit y in t he mesent eric f at on T 2- w eight ed images. Inc reased signal int ensit y w it hin t he peripanc reat ic f at on f at - suppressed T 1- w eight ed images is assoc iat ed P.1125 w it h poor out c ome in pat ient s w it h ac ut e panc reat it is (174). Dissec t ion by panc reat ic enzy mes along t he mesent eric leav es c an result in f ormat ion of absc esses, pseudoc y st s, hemorrhage, ent eric f ist ulae, and lat e bow el st enoses (133). T he presenc e of gas bubbles in a mesent eric f luid c ollec t ion may be c aused by an absc ess, nec rosis w it hout inf ec t ion, or c ommunic at ion w it h t he gast roint est inal t rac t and is bet t er demonst rat ed on CT t han MRI. Pat ient s w it h mesent eric inv olv ement demonst rat ed by CT hav e a higher morbidit y and mort alit y t han pat ient s w it hout CT ev idenc e of mesent eric spread (133).

Crohn Disease Crohn disease is a c hronic granulomat ous disease of t he aliment ary t rac t t hat most c ommonly inv olv es t he small int est ine or c olon. A major benef it of CT in pat ient s w it h Crohn disease is t o ident if y and c harac t erize t he ext ramuc osal abnormalit ies, many of w hic h c ause separat ion of bow el loops on barium st udies (88). Most import ant , CT is helpf ul in dif f erent iat ing mesent eric absc ess f rom f ibrof at t y prolif erat ion or dif f use inf lammat ory reac t ion of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2428

16 - Abdominal Wall and Peritoneal Cavity mesent ery (F ig. 16- 46). Bow el w all t hic kening and mesent eric

ly mphadenopat hy are also w ell demonst rat ed (169,200). F ibrof at t y mesent eric prolif erat ion, t he most c ommon c ause of bow el loop separat ion, is c harac t erized by inc reased densit y of t he f at bet w een t he separat ed loops (70 t o - 90 HU) and lac k of a sof t t issue mass or f luid c ollec t ion in t he af f ec t ed region (76,88). Dif f use inf lammat ory reac t ion of t he mesent ery produc es a similar inc rease in densit y of t he mesent eric f at but has no c learly def ined borders. An absc ess c an be c onf ident ly diagnosed w hen a w ell- marginat ed near- w at er densit y mass is ident if ied. Oc c asionally t he mass may c ont ain gas and oral c ont rast mat erial, indic at ing c ommunic at ion w it h bow el (88,142). CT also c an be helpf ul in ident if y ing and def ining t he ext ent of sinus t rac t s and f ist ulae. In c ases in w hic h a mesent eric mass has an at t enuat ion v alue near t hat of sof t t issue, it may be dif f ic ult t o dif f erent iat e an absc ess f rom an inf lammat ory mass (142). Oc c asionally , t he ident if ic at ion of f ibrof at t y prolif erat ion of t he mesent ery on CT c an be helpf ul in est ablishing a diagnosis of Crohn disease w hen a pat ient 's inf lammat ory bow el disease is dif f ic ult t o c lassif y c linic ally bec ause mesent eric f at prolif erat ion is not a c ommon f eat ure of ulc erat iv e c olit is (92). F ibrof at t y prolif erat ion and inc reased blood f low are responsible f or t he CT appearanc e of v asc ular dilat ion and t ort uosit y , as w ell as w ide spac ing and prominenc e of t he v asa rec t a (“ c omb sign” ) seen in assoc iat ion w it h af f ec t ed bow el segment s (234) (F ig. 16- 47). MRI also c an demonst rat e t he mesent eric f indings of Crohn disease. A disadv ant age of MRI, how ev er, is it s insensit iv it y f or demonst rat ing a small amount of ext raluminal gas, w hic h is an import ant sign of bow el perf orat ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2429

16 - Abdominal Wall and Peritoneal Cavity F igure 16- 46 F ibrof at t y prolif erat ion of t he small bow el mesent ery in a pat ient w it h Crohn disease. T he small bow el mesent ery (M) adjac ent t o t he t hic kened t erminal ileum (ar r ow ) is enlarged and c ompresses surrounding dilat ed bow el loops.

Diverticulitis Alt hough f or many y ears t he f luorosc opic c ont rast enema examinat ion serv ed as t he primary imaging t est f or diagnosing div ert ic ulit is, it is limit ed in t hat it does not delineat e t he ext rac olonic ext ent of disease. T he adv ant age of CT is t hat it c learly delineat es t he ext rac olonic ext ent of disease, w hile not requiring direc t dist ent ion of t he c olon w it h c ont rast mat erial. T he most c ommon CT f inding in pat ient s w it h div ert ic ulit is is inf lammat ion of t he peric olonic f at , c harac t erized by poorly def ined sof t t issue densit y and f ine linear st rands in t he f at adjac ent t o t he inv olv ed c olon (119,148,164) (F ig. 16- 48). Ac c umulat ion of f luid w it hin t he root of t he sigmoid mesent ery is a f requent f inding in lef t - sided div ert ic ulit is (223). Ot her CT f indings inc lude c olon w all t hic kening, engorged peric olonic mesent eric v essels, int ramural sinus t rac t s, mural or ext ramural absc esses, f ist ulae, and perit onit is (239,271,290). T he sensit iv it y of CT f or t he diagnosis of div ert ic ulit is has been report ed t o be higher t han t hat of c ont rast enema (7,164). In addit ion, CT is more ac c urat e t han c ont rast enema in demonst rat ing t he ext rac olonic ext ent and c omplic at ions of div ert ic ulit is (7,67,164,284), w hic h inc lude bladder inv olv ement , uret eral obst ruc t ion, and dist ant absc esses. T he presenc e of an absc ess or an ext raint est inal gas poc ket larger t han 5 mm is assoc iat ed w it h an inc reased rat e of nonoperat iv e t reat ment f ailure (136,164,230). T he c ombinat ion of c olonic w all t hic kening and peric olonic inf lammat ory c hanges is not pat hognomonic of div ert ic ulit is and c an be mimic ked by perf orat ed c olon c arc inoma, pelv ic inf lammat ory disease, appendic it is, epiploic appendagit is, endomet riosis, Crohn disease, and ot her f orms of c olit is.

Epiploic Appendagitis T he appendic es epiploic ae are elongat ed adipose st ruc t ures t hat arise f rom t he serosal surf ac e of t he c olon (228). T hey generally are not v isible on CT images bec ause t heir f at densit y merges w it h t hat of t he surrounding peric olonic f at . How ev er, t hese appendic es c an be ident if ied in pat ient s P.1126

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2430

16 - Abdominal Wall and Peritoneal Cavity w it h a large amount of asc it es (F ig. 16- 49). T he epiploic appendages are supplied by end art eries of t he v asa rec t a longa of t he c olon and are drained

by a v ein passing t hrough t heir narrow pedic les. T orsion or v enous t hrombosis of an epiploic appendage c an c ause isc hemic or hemorrhagic inf arc t ion, leading t o a loc alized inf lammat ory proc ess t ermed epiploic appendagit is, w hic h mimic s div ert ic ulit is or appendic it is c linic ally (85,299). T he CT appearanc e is t hat of a peric olonic ov al of higher t han normal f at at t enuat ion, w hic h represent s t he inf arc t ed epiploic appendage, surrounded by a hy perat t enuat ing rim, w hic h c orresponds t o t he inf lamed v isc eral perit oneal lining (F ig. 16- 50) (238,258,275). In some pat ient s a c ent ral high- at t enuat ion dot , indic at iv e of an engorged or t hrombosed v ein or a c ent ral area of hemorrhage, c an be ident if ied in addit ion t o loc alized c olonic w all t hic kening (223,238,275). T hic kening of adjac ent pariet al perit oneum may also be ident if ied (238,258,298). Oc c asionally , an inf arc t ed appendage may dev elop peripheral dy st rophic c alc if ic at ion (226). On T 1- and T 2- w eight ed MR images, t he peric olonic ov al is high in signal int ensit y w it h a low signal int ensit y rim (276). On post gadolinium- c helat e enhanc ed T 1- w eight ed f at suppressed images, t he rim demonst rat es enhanc ement . A hy point ense c ent ral dot also c an be ident if ied in some pat ient s (276).

F igure 16- 47 Comb sign in a pat ient w it h Crohn disease. A,B: T w o c omput ed t omography images demonst rat e prominent v asa rec t a (arrow heads) c oursing t hrough t he prolif erat iv e mesent eric f at t o supply inf lamed bow el.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2431

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 48 Div ert ic ulit is. Pelv ic c omput ed t omography demonst rat es t hic kening of t he sigmoid c olon w it h inc reased densit y of t he adjac ent sigmoid mesoc olon (ar r ow s).

Peritonitis Perit onit is is an inf lammat ion of t he perit oneum t hat c an result f rom numerous c auses and c an be eit her loc alized or dif f use. T he major t y pes of perit onit is inc lude bac t erial, P.1127 granulomat ous, and c hemic al (229). Alt hough bac t erial perit onit is is somet imes primary , it usually result s sec ondarily f rom perf orat ion of an abdominal v isc us. Common et iologies inc lude appendic it is, div ert ic ulit is, perf orat ed ulc er, perf orat ed c arc inoma, ac ut e c holec y st it is, panc reat it is, salpingoopherit is, and abdominal surgery (229). Wit h dif f use perit onit is, t he CT f indings c onsist of t hic kening of t he perit oneum, oment um and mesent ery , inc reased densit y of t he mesent eric f at , and asc it es (314). T his CT appearanc e is nonspec if ic and c an also be seen in pat ient s w it h met ast at ic c anc er or perit oneal mesot helioma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2432

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 49 Appendages epiploic ae. Comput ed t omography in a pat ient w it h a large amount of asc it es demonst rat es t he normal appendic es epiploic ae (ar r ow s) of t he sigmoid c olon (S), w hic h appear as f inger- like projec t ions of peric olic f at f loat ing w it hin t he asc it es.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2433

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 50 Epiploic appendagit is. Cont rast - enhanc ed c omput ed t omography show s an ov al f at - densit y mass surrounded by a high at t enuat ion rim (ar r ow heads) ant erior t o t he desc ending c olon (C). T he mass c ont ains a c ent ral high at t enuat ion st ruc t ure, w hic h most likely represent s t hrombosed c ent ral v essels.

T uberc ulous perit onit is has bec ome a relat iv ely unc ommon disease but remains a persist ent problem in endemic areas or in immunoc ompromised pat ient s (99). It is believ ed t o oc c ur by direc t ext ension (rupt ured ly mph nodes or perf orat ion of a t uberc ulous lesion in t he gast roint est inal or genit ourinary t rac t ) or by ly mphat ic or hemat ogenous spread (295). T he CT appearanc e of t uberc ulous perit onit is is v aried. T he most c ommon CT f eat ure is ly mphadenopat hy , predominant ly in t he mesent eric and peripanc reat ic areas (4,120) (F ig. 16- 51). Cent ral low densit y w it hin t he enlarged ly mph nodes, presumably c aused by c aseat ion nec rosis, is seen in approximat ely 40% of pat ient s (70,120). Disseminat ed My c obac t er ium t uber c ulosis inf ec t ion is f ound in approximat ely t hree f ourt hs of HIV- inf ec t ed pat ient s w ho hav e enlarged low - at t enuat ion ly mph nodes, w hereas My c obac t er ium av ium -int r ac ellular e inf ec t ion more of t en result s in sof t t issue at t enuat ion ly mphadenopat hy (234). High- densit y asc it es (20 t o 45 HU) is anot her c harac t erist ic f eat ure of t uberc ulous perit onit is, t he inc reased densit y being relat ed t o t he high prot ein

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2434

16 - Abdominal Wall and Peritoneal Cavity c ont ent of t he f luid (F ig. 16- 51) (59,70,108,120). Addit ional CT f indings inc lude t hic kening and nodularit y of perit oneal surf ac es, mesent ery , and

oment um (59,70,120) (F igs. 16- 51 and 16- 52). Alt hough t hese CT f eat ures are highly suggest iv e of t uberc ulous perit onit is, t hey are not pat hognomonic , and ot her diseases, suc h as nont uberc ulous perit onit is, ly mphoma, met ast at ic c arc inoma, perit oneal mesot helioma, and pseudomy xoma perit onei, should be inc luded in t he dif f erent ial diagnosis. T he presenc e of mesent eric c hanges, sof t t issue nodules w it h a diamet er of at least 5 mm and perit oneal masses w it h low - at t enuat ion c ent er f av ors t uberc ulous perit onit is (see F ig. 16- 52) ov er met ast at ic c arc inoma, w hic h more c ommonly has more prominent oment al inv olv ement (99). In addit ion, t he perit oneal t hic kening in t uberc ulous perit onit is t ends t o be minimal and smoot h w it h marked enhanc ement , w hereas irregular perit oneal t hic kening is more c ommon in perit oneal c arc inomat osis (247). Sc lerosing perit onit is is a serious c omplic at ion of c hronic ambulat ory perit oneal dialy sis, w hic h result s in t hic kening of t he perit oneum t hat enc loses some or all of t he small int est ine. T he main CT f indings are dif f use perit oneal t hic kening and sheet - like c alc if ic at ion, loc ulat ed f luid c ollec t ions and small bow el t et hering (2,282). A rare f orm of perit onit is, c alled sc ler osing enc apsulat ing per it onit is, is c harac t erized by a f ibrot ic membrane t hat enc ases t he small bow el, f orming a sac w it h int ernal adhesions (“ abdominal c oc oon” ), result ing in small bow el obst ruc t ion (98). T he c ause of sc lerosing enc apsulat ing perit onit is is unc ert ain. Rare parasit ic inf ec t ions of t he perit oneum inc luding Ec hinoc oc c us m ult iloc ular is, Par agonim us w est er m ani, Spar ganum m ansoni, and F asc iola hepat ic a result in mult iple sept at ed c y st ic masses in t he perit oneal c av it y , of t en assoc iat ed w it h hazy oment al sof t t issue st randing and inc reased densit y (244,289). As w it h many of t he ent it ies disc ussed abov e, t he appearanc es are nonspec if ic .

Sclerosing Mesenteritis Sc lerosing mesent erit is is an unc ommon c ondit ion of unknow n et iology c harac t erized by c hronic inf lammat ion (115,254). It c an be c at egorized int o t hree subgroups based on t he st age of t he pat hologic proc ess and it s predominant pat hology . Mesent er ic pannic ulit is is c harac t erized by c hronic inf lammat ion, m esent er ic lipody st r ophy by f at nec rosis, and r et r ac t ile m esent er it is by f ibrosis (69,152,175). Alt hough t he c ause of t he disorder is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2435

16 - Abdominal Wall and Peritoneal Cavity unknow n, it of t en is assoc iat ed w it h ot her idiopat hic inf lammat ory disorders suc h as ret roperit oneal f ibrosis, sc lerosing c holangit is, Riedel t hy roidit is, and orbit al pseudot umor (115). In one st udy , 69% of pat ient s w it h sc lerosisng mesent erit is had a c oexist ing malignanc y (61). Pat ient s may present w it h abdominal disc omf ort , but sc lerosing P.1128 mesent erit is of t en is disc ov ered inc ident ally in asy mpt omat ic pat ient s (61).

T he CT appearanc e v aries f rom a subt le dif f use inc rease in at t enuat ion of t he mesent eric f at (F ig. 16- 53) t o a solid mesent eric sof t t issue mass (F ig. 16- 54) (115,254). T he inf lamed mesent ery may demonst rat e regional mass ef f ec t w it h displac ement of adjac ent small bow el loops (300). Enlarged mesent eric ly mph nodes may also be present (see F ig. 16- 53). In some pat ient s t he normal low at t enuat ion of t he f at immediat ely surrounding t he c ent ral mesent eric v essels is preserv ed (“ f at ring” sign) (254). Rarely , t he mesent eric inf lammat ory proc ess may hav e a mult ic y st ic appearanc e, likely c aused by ly mphat ic obst ruc t ion (134,138). When a solid mass is present w it hin t he mesent ery , it somet imes c ont ains c alc if ic at ion, w hic h may be relat ed t o c ent ral f at nec rosis (see F ig. 16- 54) (110).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2436

16 - Abdominal Wall and Peritoneal Cavity F igure 16- 51 T uberc ulous perit onit is. A, B: Comput ed t omography demonst rat es enhanc ing t hic kened perit oneum (ar r ow s) and oment um (ar r ow heads) in assoc iat ion w it h high at t enuat ion asc it es (A). C : T he int raperit oneal gas (open ar r ow s) is due t o ileal perf orat ion.

F igure 16- 52 T uberc ulous perit onit is. Comput ed t omography demonst rat es ext ensiv e nodular t hic kening of t he perit oneum and small bow el mesent ery . Mult iple low at t enuat ion mesent eric and oment al masses (ar r ow s) c an be ident if ied.

T he CT appearanc e of sc lerosing mesent erit is ov erlaps w it h t hat of ot her benign and malignant disorders. Ent it ies t hat c an mimic sc lerosing mesent erit is inc lude mesent eric edema or hemorrhage, mesent eric inf lammat ion sec ondary t o panc reat it is, f ibrof at t y mesent eric prolif erat ion relat ed t o P.1129 Crohn disease, ly mphoma (part ic ularly af t er c hemot herapy ), primary mesent eric neoplasms (e.g., desmoid, mesent eric c y st , or lipomat ous t umors), perit oneal mesot helioma, and met ast at ic neoplasms, part ic ularly c arc inoid t umor (115,254,300). Caref ul rev iew of t he ent ire CT examinat ion, prior imaging st udies, and t he pat ient 's c linic al hist ory are helpf ul in suggest ing t he c orrec t diagnosis. Nev ert heless, w hen sc lerosing mesent erit is is suspec t ed, biopsy is of t en nec essary t o est ablish t he diagnosis and exc lude inf ec t ion or malignanc y .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2437

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 53 Mesent eric pannic ulit is. Coronal (A), sagit t al (B) and t ransaxial (C ) v olume- rendered c omput ed t omography show s dif f usely inc reased at t enuat ion of t he c ent ral small bow el mesent eric f at . Not e t he enlarged mesent eric ly mph nodes (ar r ow s).

T he assoc iat ion of f at nec rosis and ac ut e panc reat it is is w ell rec ognized (81). F at nec rosis, w hic h c an af f ec t t he mesent ery , oment um, or ret roperit oneum, c an also be c aused by inf ec t ion, rec ent surgery , or a f oreign body (137). T he CT appearanc e v aries f rom sof t t issue at t enuat ion mesent eric inf ilt rat ion t o nodular masses w it h sof t t issue and/or f at at t enuat ion (152,175) (F ig. 16- 55). Calc if ic at ion in t he nec rot ic c ent ral port ion may also be det ec t ed (110). Cy st ic c omponent s may be seen, represent ing dilat ed ly mphat ic s due t o ly mphat ic and/or v enous obst ruc t ion (138). In some c ases, w hen f at at t enuat ion is present , t he CT appearanc e may be indist inguishable f rom t hat of a liposarc oma or a f at - c ont aining t erat oma (see F ig. 16- 55). When sof t t issue at t enuat ion nodules are present , dif f erent ial diagnost ic c onsiderat ions

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2438

16 - Abdominal Wall and Peritoneal Cavity inc lude c arc inoid, desmoid t umor, mesent eric ly mphoma, and met ast at ic c arc inoma. T he MRI appearanc e v aries, w it h signal c harac t erist ic s suggest ing f luid or inf lammat ion (low on T 1, high on T 2), f at (high on T 1, low on T 2), or f ibrosis (low on T 1 and T 2) (152).

Segment al inf arc t ion of t he great er oment um c an result in a mass- like area of st reaky inc reased at t enuat ion w it hin t he oment al f at (F igs. 16- 56 and 16- 57) (17,233,298). T he inf arc t ion t y pic ally oc c urs on t he right side, possibly bec ause of an embry ologic v ariant of t he blood supply of t he P.1130 right side of t he oment um, w hic h predisposes it t o v enous t hrombosis (71). Pat ient s w it h oment al inf arc t ion present w it h ac ut e onset of right sided abdominal pain, w hic h c an mimic ac ut e appendic it is or c holec y st it is. Rec ognit ion on t he CT examinat ion t hat t he abnormalit y is c ent ered in t he oment um w it h only minimal if any assoc iat ed bow el or gall bladder w all t hic kening, enables t he c orrec t diagnosis. Oment al inf arc t ion c an be idiopat hic or assoc iat ed w it h adhesions, prior surgery , t rauma, or oment al t orsion (17,40). T orsion of t he great er oment um somet imes result s in a c harac t erist ic CT appearanc e c onsist ing of f ibrous and f at t y f olds in a c onv erging radial pat t ern (40).

F igure 16- 54 T w o pat ient s w it h sc lerosing mesent erit is.A: Comput ed t omography show s an inf ilt rat iv e sof t t issue mass (ar r ow s) w it hin t he root of t he small bow el mesent ery . T he mass c ont ains c ent ral c alc if ic at ions and is assoc iat ed w it h surrounding desmoplasia. T he appearanc e is indist inguishable f rom t hat of a c arc inoid t umor.B: In anot her pat ient a lobulat ed mesent eric sof t t issue mass (ar r ow heads) w it h c ent ral c alc if ic at ions is bet t er c irc umsc ribed.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2439

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 55 F at nec rosis. A large, w ell- def ined mass (M) c ont ains mixed sof t t issue and f at at t enuat ion c omponent s. T he mass arose w it hin t he t ransv erse mesoc olon af t er part ial panc reat ec t omy f or panc reat ic c anc er.

Mesenteric Cyst (Lymphangioma) A large v ariet y of benign and malignant ent it ies c an present as c y st ic mesent eric or oment al masses. T hese inc lude ly mphangioma, ent eric duplic at ion c y st , mesot helial c y st , ov arian c y st , nonpanc reat ic pseudoc y st , c y st ic mesot helioma, c y st ic mesenc hy mal t umor, c y st ic t erat oma and ec hinoc oc c al c y st . Alt hough CT f indings may suggest a spec if ic diagnosis in some c ases, hist ologic diagnosis is of t en needed (249,285). Mesent eric c y st s (or ly mphangiomas) are benign masses of v asc ular origin t hat show ly mphat ic dif f erent iat ion (160). T hey originat e most c ommonly in t he small bow el mesent ery , less c ommonly in t he oment um, mesoc olon and ret roperit oneum (107,264). T hey c ont ain eit her serous or c hy lous f luid (301). Clinic ally , mesent eric c y st s usually are disc ov ered inc ident ally as an asy mpt omat ic abdominal mass, but t hey c an c ause c hronic abdominal pain or ac ut e pain sec ondary t o a c omplic at ion suc h as t orsion, rupt ure, hemorrhage, or gast roint est inal obst ruc t ion. Mesent eric c y st s appear on CT as w elldef ined, near- w at er at t enuat ion, abdominal masses t hat somet imes c ont ain higher densit y sept a (F ig. 16- 58) (107). When numerous t hic k sept a are present , t he mass may hav e an ov erall at t enuat ion great er t han t hat of w at er (F ig. 16- 59). In some c ases a t hin w all c an be ident if ied peripherally . Chy lous

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2440

16 - Abdominal Wall and Peritoneal Cavity

c y st s oc c asionally hav e a pat hognomonic f at –f luid lay er, demonst rable w it h CT , P.1131 P.1132 MRI, or ult rasound. T he c y st s are usually single, but c an be mult iple and v ary w idely in size. In c hildren t he c y st s may f ill most of t he abdomen (107). Alt hough t he c y st c ont ent is usually w at er at t enuat ion, c y st s c ont aining muc inous f luid or hemorrhage c an hav e higher at t enuat ion v alues (314). Mesent eric c y st s hav e signal int ensit y c harac t erist ic s similar t o t hose of f luid, low on T 1- w eight ed images and high on T 2- w eight ed images (160). Negat iv e CT at t enuat ion v alues or short ened T 1 signal int ensit y c harac t erist ic s on MRI may indic at e t he presenc e of f at (285).

F igure 16- 56 Segment al inf arc t ion of t he great er oment um. A: Comput ed t omography demonst rat es an ill- def ined area of inc reased at t enuat ion (ar r ow s) w it hin t he oment al f at ant erior t o t he asc ending c olon. B: F ollow - up examinat ion 5 day s lat er show s t y pic al ev olut ion of t he abnormalit y , w it h a linear band of inc reased at t enuat ion (ar r ow heads) surrounding t he af f ec t ed area.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2441

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 57 Segment al inf arc t ion of t he great er oment um. Cont rast enhanc ed c omput ed t omography demonst rat es a mass- like area het erogeneous inc reased at t enuat ion w it hin t he great er oment um (ar r ow s). F ollow - up examinat ion (not show n) show ed c omplet e resolut ion. (Court esy of Alv aro Huet e, MD.)

F igure 16- 58 Ly mphangioma. A large homogeneous w at er at t enuat ion mass (L) arising f rom t he gast rohepat ic ligament surrounds t he lef t gast ric v essels (ar r ow ) and displac es t he st omac h t o t he lef t .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2442

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 59 Mesent eric ly mphangioma. A large mass (L) arising f rom t he small bow el mesent ery c ont ains numerous t hic k sept at ions. Court esy of Alv aro Huet e, M.D.

Other Nonneoplastic Processes of the Mesentery Mesent eric hemorrhage, similar t o hemorrhage elsew here in t he perit oneum, has a v aried appearanc e depending on t he age and ext ent of t he bleeding. Ac ut e mesent eric hemorrhage may produc e loc alized, w ell- def ined, sof t t issue masses adjac ent t o bow el loops or larger “ c ake- like” masses t hat displac e t he bow el loops (314). When present ing as a f oc al mass, mesent eric hemat oma c an be mist aken f or a primary or met ast at ic mesent eric t umor, an exophy t ic t umor of t he bow el, or a mesent eric c y st w it h hemorrhage (235). Wit h dif f use inv olv ement t he mesent eric f at is oblit erat ed (F ig. 16- 60). T he at t enuat ion of t he hemat oma is init ially high w it h a gradual dec rease in at t enuat ion during a period of w eeks f ollow ed by gradual resorpt ion of t he remaining seroma. Af t er c omplet e resorpt ion, t he mesent ery may appear t o ret urn t o normal or may c ont ain residual f ibrosis (314). T he t erm pseudot um or al lipom at osis of t he m esent er y ref ers t o t he exc essiv e prolif erat ion of normal mesent eric f at . T his benign c ondit ion c an be idiopat hic or c an be seen in assoc iat ion w it h obesit y , Cushing sy ndrome, or st eroid t herapy (162). On c ont rast st udies of t he gast roint est inal t rac t , mesent eric lipomat osis may displac e bow el loops, simulat ing an abdominal mass or asc it es.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2443

16 - Abdominal Wall and Peritoneal Cavity

CT c an exc lude t he presenc e of neoplasm by show ing t hat t he displac ement is c aused by eit her dif f use or f oc al ac c umulat ion of normal f at (51,162,270).

F igure 16- 60 Mesent eric hemorrhage. Coronal c omput ed t omography demonst rat es an irregularly shaped c ollec t ion of f luid (arrow s) t hat c ont ains areas of high at t enuat ion, surrounding t he v essels at t he root of t he small bow el mesent ery . Not e t he blood in t he right perihepat ic spac e (ar r ow heads) and in t he right parac olic gut t er (H).

Sy st emic amy loidosis is c harac t erized by dif f use ext rac ellular t issue deposit ion of an amorphous eosinophilic prot ein- poly sac c haride c omplex (57). Amy loidosis c an oc c ur as a primary proc ess or in assoc iat ion w it h c hronic inf lammat ory

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2444

16 - Abdominal Wall and Peritoneal Cavity disease or mult iple my eloma. Inv olv ement of t he mesent ery , w hen ext ensiv e,

is easily demonst rat ed by CT (5). T he CT appearanc e, c onsist ing of inc reased densit y of mesent eric f at w it h enc asement of mesent eric v essels, P.1133 is indist inguishable f rom ot her disease proc esses c ausing dif f use mesent eric inf ilt rat ion inc luding perit onit is, met ast at ic c arc inoma, and perit oneal mesot helioma (56). Addit ional rare c auses of mesent eric inf ilt rat ion t hat c an hav e a similar appearanc e are ext ramedullary hemat opoeisis (96,226) and sarc oidosis (226). T he most c ommonly rec ognized radiographic manif est at ion of Whipple disease is t hic kening of t he v alv ulae c onniv ent es of t he small bow el. How ev er, CT is c apable of demonst rat ing some of t he less w ell- rec ognized ext raint est inal manif est at ions of t he disease inc luding low - densit y ret roperit oneal and mesent eric ly mphadenopat hy , and sac roiliit is (163,245). T he enlarged ly mph nodes in Whipple disease may be low in at t enuat ion sec ondary t o deposit ion of neut ral f at and f at t y ac ids w it hin t he nodes (163). Mesent eric v enous t hrombosis is responsible f or 5% t o 15% of c ases of int est inal isc hemia (95). T he superior mesent eric v ein (SMV), w hic h is inv olv ed in 95% of t hese c ases, is easily imaged by CT . T he t y pic al appearanc e of c hronic SMV t hrombosis c onsist s of enlargement of t he v ein w it h c ent ral low densit y surrounded by a higher densit y w all (250) (F ig. 16- 61). T he w all of t he v ein enhanc es af t er administ rat ion of int rav enous c ont rast mat erial, possibly due t o enhanc ement of t he art erially supplied v asa v asorum (329). T he t hrombus may be higher in at t enuat ion t han sof t t issue w hen SMV t hrombosis is ac ut e. Assoc iat ed port al v enous or splenic v enous t hrombosis may be seen (250). In some c ases, mesent eric v enous t hrombosis is assoc iat ed w it h inc reased densit y of t he mesent eric f at and poor def init ion of segment al mesent eric v essels, due t o mesent eric edema (272). T hic kening of t he bow el w all may also be present . If t he mesent eric isc hemia is sev ere enough t o c ause bow el inf arc t ion, int ramural, port al v ein, or mesent eric v ein gas may also be ident if ied (73). T hese assoc iat ed f indings are usually absent w hen t he t hrombus is nonoc c lusiv e.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2445

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 61 Superior mesent eric v ein (SMV) t hrombosis. T he SMV (ar r ow ) is enlarged and c ont ains c ent ral low at t enuat ion surrounded by a higher densit y w all.

Endomet riosis c an dif f usely inv olv e t he perit oneum w it h c y st ic , solid, or mixed masses t hroughout t he oment um, mesent ery , and perit oneal surf ac es. Highat t enuat ion asc it es may also be present . Alt hough t he CT appearanc e is nonspec if ic , t his diagnosis should be c onsidered in w omen of c hildbearing age. Dif f erent ial diagnost ic c onsiderat ions inc lude perit oneal c arc inomat osis, pseudomy xoma perit onei, ly mphoma, and t uberc ulous perit onit is. In most c ases how ev er, perit oneal endomet rial implant s are t oo small t o be ident if ied at CT . On MR images, large endomet riomas appear as high signal int ensit y masses on T 1- w eight ed images and low signal int ensit y masses w it h areas of high signal int ensit y on T 2- w eight ed images (27). Endomet riosis may also appear as mult iple small c y st s t hat are hy perint ense on T 1- w eight ed images w it h v ariable signal int ensit y on T 2- w eight ed images (11,27). Most endomet riomas remain bright on gadolinium- c helat e enhanc ed T 1- w eight ed images, and enhanc ement of adjac ent perit oneal surf ac es is also f requent ly seen (11). Alt hough MR imaging is superior t o CT in demonst rat ing perit oneal endomet riosis, MR also is limit ed in demonst rat ing small perit oneal implant s (94). In one st udy , gadolinium- enhanc ed T 1- w eight ed f at - suppressed MR demonst rat ed 27% of endomet rial implant s w it h a posit iv e predic t iv e v alue of 64% (11). Cast leman disease is an idiopat hic , benign ent it y c harac t erized by prolif erat ion of ly mphoid t issue int o t umoral masses. It is most of t en seen as a solit ary

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2446

16 - Abdominal Wall and Peritoneal Cavity mediast inal mass but c an oc c ur as solit ary or w idespread mesent eric disease (F ig. 16- 62) (75,80). Classic ally , marked enhanc ement is seen on CT (75,80).

F igure 16- 62 Cast leman disease. A homogeneously enhanc ing mass (ar r ow ) at t he root of t he small bow el mesent ery has produc ed small bow el obst ruc t ion. T he mass c ont ains a small amount of c alc if ic at ion.

P.1134

Primary Neoplasms of the Peritoneum Cy st ic mesot helioma (also c alled m ult ic y st ic m esot heliom a, benign c y st ic m esot heliom a and m ult iloc ular per it oneal inc lusion c y st ) is a rare neoplasm of perit oneal origin. It oc c urs predominant ly in w omen of c hild- bearing age (210,311). Whet her it is a t rue neoplasm is c ont rov ersial. Cy st ic mesot helioma is c onsidered by some researc hers t o be a benign neoplasm (210) and by ot hers t o be an int ermediat e grade neoplasm, bet w een benign adenomat oid t umor of t he perit oneum and malignant perit oneal mesot helioma (311). St ill ot hers c onsider it t o represent nonneoplast ic mesot helial prolif erat ion rat her t han a t rue neoplasm (251). On CT , c y st ic mesot helioma appears as a mult iloc ular c y st ic mass t hat may exert mass ef f ec t on adjac ent anat omic st ruc t ures but show s no signs of inv asion (101,218). On MRI, t he c y st s are low in signal int ensit y on T 1- w eight ed images and int ermediat e or high signal int ensit y on T 2- w eight ed images (210,218,320). T he imaging appearanc e of c y st ic mesot helioma may be ident ic al t o t hat of ly mphangioma and ov erlaps

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2447

16 - Abdominal Wall and Peritoneal Cavity w it h t hat of ot her c y st ic perit oneal masses. T heref ore, diagnosis requires hist ologic ev aluat ion (320). Inf lammat ory pseudot umor, also know n as m y of ibr oblast ic t um or , is a rare reac t iv e lesion t hat c an inv olv e t he perit oneum. It usually oc c urs in y oung indiv iduals and c an appear as an inf ilt rat iv e mass or as mult iple w ell- def ined perit oneal masses (226). Primary serous papillary c arc inoma of t he perit oneum is a rare primary neoplasm of t he perit oneum t hat oc c urs primarily in post menopausal w omen (141). It is c harac t erized by abdominal c arc inomat osis and no inv olv ement or only surf ac e inv olv ement of t he ov aries (78). T he c linic al and hist opat hologic f eat ures of primary serous papillary c arc inoma of t he perit oneum are

indist inguishable f rom t hose of met ast at ic ov arian c arc inoma (190). On imaging st udies, t he presenc e of asc it es and ext ensiv e perit oneal and oment al t umor inv olv ement in t he absenc e of an ov arian mass or ev idenc e of a primary t umor in t he gast roint est inal t rac t should suggest t he diagnosis (44,46,78,141,281,330). Perit oneal c alc if ic at ions and ly mph node enlargement may also be seen. Mesot helioma is a rare malignant neoplasm arising f rom t he mesot helial c ells lining t he pleura, perit oneum, and peric ardium. Perit oneal inv olv ement may oc c ur, eit her alone or in c ombinat ion w it h pleural inv olv ement . T he CT f indings c orrelat e w it h t he t w o major c linic al t y pes of perit oneal mesot helioma. In t he “ w et ” t y pe, asc it es is assoc iat ed w it h perit oneal, mesent eric and oment al t hic kening t hat may appear irregular or nodular (97,242,286,316) (F igs. 16- 63 and 16- 64). T he mesent eric inv olv ement may produc e a “ st ellat e” appearanc e due t o t hic kening of t he periv asc ular bundles by t umor (F ig. 16- 65) (316). In t he “ dry - painf ul” t y pe, CT demonst rat es mult iple small masses or a single dominant mass isolat ed t o one part of t he abdomen (140,286). In adv anc ed c ases, solid t umor w it h areas of c y st ic degenerat ion may f ill t he ent ire abdomen. T he CT appearanc e of perit oneal mesot helioma may be indist inguishable f rom perit oneal c arc inomat osis, ly mphoma, and benign disease proc esses suc h as t uberc ulous perit onit is. T he amount of asc it es relat iv e t o t he sof t t issue c omponent of mesot helioma may be disproport ionat ely small as c ompared w it h perit oneal c arc inomat osis in w hic h asc it es is usually a prominent f eat ure (242).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2448

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 63 Primary perit oneal mesot helioma. Cont rast - enhanc ed c omput ed t omography show s asc it es and dif f use t hic kening of t he perit oneum (ar r ow heads) and oment um (ar r ow s). T he appearanc e is indist inguishable f rom t hat of perit oneal c arc inomat osis.

Desmoplast ic round c ell t umor of t he abdomen is a rare aggressiv e malignant neoplasm t hat oc c urs in adolesc ent s and y oung adult s (mean age, 20 t o 25 y ears) (47,82,227,292). T he CT f indings range f rom one or more large lobulat ed perit oneal masses t o dif f use irregular perit oneal t hic kening w it hout disc ret e masses (47,227,292). T he masses may c ont ain areas of c ent ral low at t enuat ion or punc t uat e c alc if ic at ion. On MRI, t he masses demonst rat e low signal int ensit y on T 1- w eight ed images, high signal int ensit y on T 2- w eight ed images, and het erogeneous c ont rast enhanc ement P.1135 w it h c ent ral hy point ensit y , indic at iv e of nec rosis (292). F luid- f luid lev els may be seen on T 2- w eight ed images, c orresponding t o int rat umoral hemorrhage (292). Asc it es and abdominal or pelv ic ly mphadenopat hy may also be present . Met ast ases most c ommonly inv olv e t he liv er, less c ommonly t he t horax and bones (47,227,292).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2449

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 64 Primary perit oneal mesot helioma. Cont rast - enhanc ed c omput ed t omography show s dif f use t hic kening of t he great er oment um (ar r ow heads) and t he leav es of t he small bow el mesent ery (ar r ow s). A drainage c at het er is present w it hin t he asc it es on t he right side of t he abdomen.

F igure 16- 65 Primary perit oneal mesot helioma. Cont rast - enhanc ed c omput ed t omography demonst rat es asc it es, t hic kening of t he small bow el mesent ery , and mild t hic kening and enhanc ement of t he perit oneal lining (ar r ow heads).

Primary Neoplasms of the Mesentery and Omentum

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2450

16 - Abdominal Wall and Peritoneal Cavity Primary neoplasms of t he mesent eries and great er oment um are rare and generally of mesenc hy mal origin (268). T he mesent eric desmoid t umor is a nonenc apsulat ed, loc ally inv asiv e f orm of f ibromat osis (201). It oc c urs sporadic ally but is part ic ularly c ommon in pat ient s w it h Gardner sy ndrome, espec ially in t hose w ho hav e undergone abdominal surgery (21,172,201). On CT , a desmoid t umor appears as a sof t t issue mass displac ing adjac ent v isc eral st ruc t ures (21) (F igs. 16- 66 and 16- 67). Alt hough t he mass may appear w ell c irc umsc ribed, it of t en has irregular margins ext ending int o t he mesent eric f at , ref lec t ing it s inf ilt rat iv e nat ure (see F igs. 16- 67). Less c ommonly t he mass may hav e a “ w horled” appearanc e (13,31).

Mesent eric desmoid t umors demonst rat e c ont rast enhanc ement , w hic h may be homogeneous or het erogeneous. Ot her neoplasms suc h as mesent eric met ast ases and ly mphoma c an hav e a similar CT appearanc e. On MRI desmoid t umors appear hy po- or isoint ense relat iv e t o musc le on T 1- w eight ed images, w it h v ariable signal int ensit y on T 2- w eight ed images, ref lec t ing t heir relat iv e c ellularit y and f ibrous c ont ent (13,39,111). High T 2 signal int ensit y and marked enhanc ement af t er int rav enous c ont rast medium administ rat ion are indic at iv e of high t umor c ellularit y , w hic h is predic t iv e of rapid t umor grow t h (111).

F igure 16- 66 Desmoid t umor. Cont rast - enhanc ed c omput ed t omography show s a homogeneously enhanc ing sof t t issue mass (M) w it h irregular margins w it hin t he small bow el mesent ery . T he mass has result ed in small bow el obst ruc t ion. Not e t he dilat ed, f luid- f illed small bow el loops (ar r ow s).

Lipomat ous t umors, w hic h oc c ur predominant ly in t he ret roperit oneum, rarely inv olv e t he perit oneal c av it y . Benign lipomas c onsist predominant ly of f at ,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2451

16 - Abdominal Wall and Peritoneal Cavity w hic h is ref lec t ed in t heir CT at t enuat ion and MR signal c harac t erist ic s.

My olipoma is a rare benign mass t hat c ont ains f at and sof t t issue densit y and c an simulat e a liposarc oma (F ig. 16- 68). Mult iple hist ologic subt y pes of liposarc oma exist , eac h w it h c orresponding CT and MR c harac t erist ic s. Welldif f erent iat ed liposarc oma c an be of lipomat ous or sc lerosing t y pe, w it h CT and MR appearanc e of f at or musc le, respec t iv ely . My xoid liposarc oma has an appearanc e on unenhanc ed CT t hat is similar t o w at er, w it h ret ic ular enhanc ement af t er administ rat ion of int rav enous c ont rast mat erial. Round c ell and pleiomorphic liposarc omas are nonf at t y t umors w it h nonspec if ic sof t t issue appearanc e on CT and MRI (F ig. 16- 69) (144). Benign or malignant primary perit oneal mesent eric and oment al t umors ot her t han desmoid and lipomat ous t umors are ext remely rare but c an arise f rom any of t he mesenc hy mal t issue element s (106,123,124,151,156,179,198,199,236) (F igs. 16- 70 and 16- 71). Primary oment al and mesent eric gast roint est inal st romal t umors are indist inguishable f rom ot her sarc omas arising f rom t hese st ruc t ures (143). Primary mesent eric and oment al t erat omas hav e also been report ed (106,312). Bec ause bot h benign and malignant primary mesent eric and oment al t umors may demonst rat e c y st ic , solid, and c omplex f eat ures, hist ologic diagnosis is usually required.

Secondary Neoplasms T he most c ommon malignant neoplasms inv olv ing t he perit oneum are met ast at ic c arc inoma and ly mphoma. Met ast ases usually arise f rom t he st omac h, c olon, or ov ary P.1136 P.1137 and less c ommonly f rom t he panc reas, biliary t rac t , or ut erus (1,60). Renal c ell c arc inoma, t ransit ional c ell c arc inoma of t he bladder and gast roint est inal leiomy osarc oma are report ed as rare sit es of origin (225,243,291). Very rarely , a lat e rec urrenc e of malignant melanoma may present w it h perit oneal inv olv ement (154). Prior t o t he av ailabilit y of CT , perit oneal met ast ases w ere not det ec t able radiographic ally unt il t hey w ere large enough t o displac e adjac ent organs or c ause int est inal obst ruc t ion. Now w it h t he rout ine use of mult idet ec t or- row CT , perit oneal met ast ases less t han 5 mm in diamet er c an be det ec t ed, alt hough t he sensit iv it y of CT f or demonst rat ing subc ent imet er met ast ases remains limit ed. A st udy using single- det ec t or row CT t o ev aluat e pat ient s w it h ov arian c anc er preoperat iv ely demonst rat ed a sensit iv it y of 25%

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2452

16 - Abdominal Wall and Peritoneal Cavity t o 50% f or met ast ases less t han 1 c m in diamet er, alt hough t he ov erall

sensit iv it y f or perit oneal met ast ases w as 85% t o 93% (49). MRI using breat hhold T 1- w eight ed gradient ec ho imaging w it h f at suppression and gadoliniumc helat e enhanc ement is also an exc ellent t ec hnique f or demonst rat ing perit oneal t umors, w it h report ed sensit iv it ies of 84% t o 95% (166,167,262,293). A mult i- inst it ut ional st udy c omparing CT , MRI, and ult rasound f or t he st aging of pat ient s w it h adv anc ed ov arian c anc er f ound no st at ist ic ally signif ic ant dif f erenc e bet w een MRI and CT f or demonst rat ing perit oneal met ast ases (95% and 92%, respec t iv ely ) (293). In t hat st udy , bot h CT and MRI w ere superior t o ult rasound (sensit iv it y , 69%).

F igure 16- 67 Mesent eric desmoid t umor in t w o pat ient s w it h Gardner sy ndrome.A, B: An enhanc ing sof t t issue mass w it h irregular margins (M) inf ilt rat es t he small bow el mesent ery , enc asing mesent eric v essels and displac ing small bow el loops.C : A large mass (m) w it hin t he small bow el mesent ery show s mild het erogeneous enhanc ement . Not e t he irregularit y along t he lef t post erior and right lat eral borders (ar r ow s) Bot h pat ient s had undergone t ot al c olec t omy .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2453

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 68 My olipoma. Cont rast - enhanc ed c omput ed t omography show s an enc apsulat ed het erogeneous f at - c ont aining mass (M) w it hin t he great er oment um. T he appearanc e is indist inguishable f rom t hat of mass- like f at nec rosis or liposarc oma.

F igure 16- 69 Pleiomorphic liposarc oma. Cont rast - enhanc ed c omput ed t omography demonst rat es a large het erogeneously enhanc ing mass (M) in t he small bow el mesent ery .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2454

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 70 Primary angiosarc oma of t he oment um. Large mass (M) in t he great er oment um c ont aining near- w at er at t enuat ion and enhanc ing sof t t issue at t enuat ion c omponent s.

F igure 16- 71 Spindle c ell sarc oma of t he oment um. Large het erogeneously enhanc ing, v asc ular mass (M) in t he great er oment um displac es adjac ent bow el.

Rigorous at t ent ion t o t ec hnique is import ant in det ec t ing small mesent eric and oment al t umor implant s. Administ rat ion of int raperit oneal air or iodinat ed c ont rast mat erial may improv e t he det ec t ion of implant s in some

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2455

16 - Abdominal Wall and Peritoneal Cavity int raperit oneal c ompart ment s (38,105), but suc h t ec hniques are not prac t ic al f or rout ine imaging. In pat ient s w it h a large amount of asc it es, ult rasound is c apable of demonst rat ing superf ic ial perit oneal and oment al t umor nodules as small as 2 t o 3 mm bec ause of t he ac oust ic w indow prov ided by t he perit oneal f luid (325). How ev er, it is dif f ic ult t o det ec t perit oneal masses w it h ult rasound in pat ient s w it h lit t le or no asc it es. F urt hermore, c ent rally loc at ed t umors are poorly imaged by ult rasound bec ause of t he ac oust ic impedanc e of bow el gas and mesent eric f at (30). P.1138 Met ast at ic neoplasm c an disseminat e t hrough t he perit oneal c av it y by f our pat hw ay s: direc t spread along mesent eric and ligament ous at t ac hment s, int raperit oneal seeding, ly mphat ic ext ension, and embolic hemat ogenous disseminat ion (184). Many neoplasms met ast asize predominant ly by one part ic ular rout e produc ing c harac t erist ic CT f indings (158).

Direct Spread Along Peritoneal Surfaces Malignant neoplasms of t he ov ary , st omac h, c olon, and panc reas t hat hav e penet rat ed bey ond t he borders of t hese organs c an spread direc t ly along t he adjac ent v isc eral perit oneal surf ac es t o inv olv e ot her perit oneal st ruc t ures. Neoplast ic spread along perit oneal pat hw ay s c an also inv olv e bow el at some dist anc e f rom t he primary t umor. T he t ransv erse mesoc olon serv es as a major rout e of spread f rom t he st omac h, c olon, and panc reas. T he gast roc olic ligament (great er oment um) is anot her import ant pat hw ay bet w een st omac h and c olon. Gast ric malignanc ies c an also ext end along t he gast rosplenic ligament t o t he spleen, w hereas neoplasms in t he t ail of t he panc reas may spread v ia t he phrenic oc olic ligament t o inv olv e t he anat omic splenic f lexure of t he c olon (185). Biliary neoplasms of t en spread along t he gast rohepat ic and hepat oduodenal ligament s. Ov arian c arc inoma spreads dif f usely along all adjac ent mesot helial surf ac es. T he CT appearanc e of direc t perit oneal ext ension of t umor depends on t he degree of spread. Early perit oneal inf ilt rat ion produc es an inc rease in t he densit y of t he f at adjac ent t o t he neoplasm. More adv anc ed spread result s in a mass t hat is c ont iguous w it h t he primary neoplasm and of t en ext ends along t he expec t ed c ourse of t he ligament ous at t ac hment t o inv olv e adjac ent organs (217). Bec ause of t heir c ont inuit y w it h t he ret roperit oneum, t he perit oneal ligament s, in addit ion t o

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2456

16 - Abdominal Wall and Peritoneal Cavity

serv ing as t he av enues of int raperit oneal t umor spread, also serv e as c onduit s of disease spread bet w een t he perit oneum and ret roperit oneum (185).

F igure 16- 72 Perit oneal c arc inomat osis in a pat ient w it h gast ric adenoc arc inoma. A, B, C : T he t ransv erse mesoc olon (ar r ow heads), great er oment um (ar r ow s), and small bow el mesent ery (open ar r ow s) are inf ilt rat ed w it h innumerable t iny sof t t issue nodules.

Neoplast ic inf ilt rat ion of t he great er oment um c an produc e a dist inc t iv e CT or MR imaging appearanc e ranging f rom small nodules or st rands of sof t t issue t hat inc rease t he densit y of t he f at ant erior t o t he c olon or small int est ine (F igs. 16- 72 and 16- 73) t o large masses t hat separat e t he c olon or small int est ine f rom t he ant erior abdominal w all (“ oment al c akes” ) (54,159) (F igs. 16- 74 and 16- 75). P.1139 Ext ensiv e neoplast ic inf ilt rat ion of t he oment um is produc ed most f requent ly by met ast at ic ov arian c arc inoma but c an oc c ur w it h ot her neoplasms. Oc c asionally oment al or ot her perit oneal met ast ases f rom ov arian c arc inoma c alc if y (F ig. 16- 76). T his is most c ommonly seen w it h serous papillary c y st adenoc arc inoma in w hic h psammomat ous c alc if ic at ions are seen hist ologic ally (192). Inf lammat ory t hic kening of t he oment um, suc h as t hat

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2457

16 - Abdominal Wall and Peritoneal Cavity

produc ed by perit onit is, may be indist inguishable f rom neoplast ic inf ilt rat ion of t he oment um (54).

F igure 16- 73 Oment al met ast ases. T 1- w eight ed gradient - ec ho image w it h f at suppression ac quired af t er int rav enous administ rat ion of gadolinium- c helat e show s enhanc ement of t he great er oment um (ar r ow heads), w hic h is dif f usely inf ilt rat ed w it h met ast ases f rom ov arian c arc inoma.

F igure 16- 74 Met ast at ic ov arian c arc inoma. Cont rast - enhanc ed c omput ed t omography show s a large amount of asc it es assoc iat ed w it h a c onglomerat e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2458

16 - Abdominal Wall and Peritoneal Cavity sof t t issue mass inv olv ing t he great er oment um (ar r ow s). Also not e mult iple smaller masses inv olv ing t he small bow el mesent ery (open ar r ow s) and perit oneum (ar r ow heads).

F igure 16- 75 Met ast at ic c olon c arc inoma. Cont rast - enhanc ed c omput ed t omography demonst rat es massiv e asc it es w it h enhanc ing met ast ases t hat inv olv e t he great er oment um dif f usely (ar r ow heads).

Inv olv ement of t he small bow el mesent ery by c arc inoid t umor of t en produc es a c harac t erist ic CT appearanc e. T he t riad of c alc if ic at ion w it hin a mesent eric mass, radiat ing sof t t issue st rands due t o reac t iv e desmoplasia around t he mass, and mural t hic kening of an adjac ent bow el loop is highly suggest iv e of t his diagnosis (220,321) (F igs. 16- 77 and 16- 78). Calc if ic at ion may be det ec t ed in up t o 70% of c ases (220) (F igs. 16- 77 and 16- 79). Moderat e c ont rast P.1140 enhanc ement of t he mesent eric mass is t y pic al on bot h CT and MR examinat ions (14). Mesent eric v enous c ongest ion may be present sec ondary t o obst ruc t ion of mesent eric v eins by t he mass (see F igs. 16- 77C and 1678B). Many pat ient s hav e liv er met ast ases at t he t ime of diagnosis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2459

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 76 Calc if ied met ast asis in a pat ient w it h ov arian c arc inoma. Comput ed t omography w it h bone w indow set t ings demonst rat es a c alc ium at t enuat ion met ast asis in Morison's pouc h (ar r ow ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2460

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 77 Met ast at ic c arc inoid t umor. A: T ransaxial c omput ed t omography show s a lobulat ed sof t t issue mass (ar r ow ) w it h punc t at e c ent ral c alc if ic at ions at t he root of t he small bow el mesent ery . St rands of sof t t issue densit y radiat ing f rom t he mass t ow ard t he small bow el loops are indic at iv e of desmoplast ic response t o t he t umor. B: Coronal image also demonst rat es t he c harac t erist ic f eat ures of t he mass. C : Coronal maximum int ensit y projec t ion (MIP) image show s engorgement of t he mesent eric v eins due t o part ial obst ruc t ion by t he mass. Not e t he large hepat ic met ast asis (ar r ow head).

Intraperitoneal Seeding

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2461

16 - Abdominal Wall and Peritoneal Cavity

Int raperit oneal seeding of neoplasm depends on t he nat ural f low of f luid w it hin t he perit oneal c av it y , w hic h is gov erned by t he c ompart ment alizat ion of t he perit oneal spac es in c ombinat ion w it h t he ef f ec t s of grav it y and c hanges in int raabdominal pressure c aused by respirat ion (186). T he most c ommon sit es of pooling of asc it es and subsequent f ixat ion and grow t h of perit oneal met ast ases are t he pouc h of Douglas (F igs. 16- 79 and 16- 80), t he low er small bow el mesent ery near t he ileoc ec al junc t ion, t he sigmoid mesoc olon, and t he right parac olic gut t er (186). T he primary neoplasms t hat most c ommonly spread P.1141 by t his rout e are adenoc arc inoma of t he ov ary , c olon, st omac h, and panc reas. Approximat ely 70% of pat ient s w it h ov arian c arc inoma hav e perit oneal inv olv ement at t he t ime of diagnosis (322). On CT , seeded met ast ases appear as sof t t issue masses, f requent ly assoc iat ed w it h asc it es, at one or more of t he sit es of normal pooling (F ig. 16- 81) (132). In some c ases t he perit oneum is dif f usely t hic kened. If a moderat e amount of asc it es is present , perit oneal implant s less t han 5 mm in diamet er c an be ident if ied. If t he met ast ases are v ery small, asc it es may be t he only sign of int raperit oneal seeding. When lit t le or no asc it es is present , t he only CT manif est at ion of int raabdominal c arc inomat osis may be replac ement of t he normal mesent eric f at densit y w it h sof t t issue densit y .

F igure 16- 78 Met ast at ic c arc inoid t umor.A: Comput ed t omography show s a sof t t issue mass (ar r ow ) w it h c ent ral c alc if ic at ions in t he root of t he small bow el mesent ery . Not e t he w all t hic kening of t he adjac ent loop of small bow el (S).B: Volume- rendered image demonst rat es t he desmoplast ic reac t ion w it hin t he mesent eric f at and engorgement of t he mesent eric v eins.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2462

16 - Abdominal Wall and Peritoneal Cavity T he small bow el mesent ery and t he great er oment um are f requent ly inv olv ed by int raperit oneally disseminat ed t umor. F our general CT pat t erns of mesent eric inv olv ement hav e been desc ribed: rounded masses, c ake- like masses, ill- def ined masses, and a st ellat e pat t ern (315). Rounded masses are seen most c ommonly w it h non- Hodgkin ly mphoma (result ing primarily f rom ly mphadenopat hy rat her t han int raperit oneal seeding) (26,315) (F igs. 16- 82 and 16- 83) but c an also be seen w it h ot her met ast at ic t umors (F igs. 16- 84 and 16- 85). Irregular ill- def ined and c ake- like masses are seen most of t en

w it h ov arian c arc inoma, alt hough non- Hodgkin ly mphoma and ot her met ast at ic c arc inomas c an produc e a similar appearanc e. Cy st ic mesent eric masses are an oc c asional manif est at ion of ov arian c arc inoma. T he st ellat e pat t ern, c onsist ing of a radiat ing pat t ern of t he mesent eric leav es, c an be produc ed by a number of met ast at ic c arc inomas, inc luding ov arian, panc reat ic , c olonic , and breast (F ig. 16- 86). T his pat t ern result s f rom dif f use mesent eric t umor inf ilt rat ion c ausing t hic kening and rigidit y of t he periv asc ular bundles (159). T hese mesent eric pat t erns, alt hough c harac t erist ic of met ast at ic inv olv ement , are by no means spec if ic and c an be mimic ked by primary perit oneal neoplasms suc h as mesot helioma (see F ig. 16- 65) and by inf lammat ory proc esses suc h as panc reat it is and t uberc ulous perit onit is. A dist inc t iv e CT appearanc e is produc ed by pseudomy xoma perit onei in w hic h t he perit oneal surf ac es bec ome dif f usely inv olv ed w it h large amount s of muc inous mat erial. Alt hough t here is c ont inued debat e regarding t he sit e of origin of pseudomy xoma perit onei, c linic opat hologic st udies suggest t hat t he v ast majorit y of c ases arise f rom primary muc inous adenomas of t he appendix, w it h t he ov aries being sec ondarily inv olv ed (79,231,248,326). Alt hough a more benign f orm (disseminat ed perit oneal adenomuc inosis) and a more malignant f orm (perit oneal muc inous c arc inomat osis) of t he disease hav e been desc ribed, t he imaging f indings of t he t w o f orms ov erlap (22). CT f indings inc lude low at t enuat ion masses w it h disc ret e w alls or dif f use int raperit oneal low at t enuat ion mat erial t hat may c ont ain sept at ions and of t en c auses sc alloping of t he hepat ic , splenic and mesent eric margins (58,177,206,263,287,308,324) (F igs. 16- 87, 16- 88, 16- 89). Calc if ic at ions are not unc ommon in pat ient s w it h large v olume disease (177), part ic ularly af t er c hemot herapy (176,287). If t he w alls of t he c y st ic masses are t hin, t he CT appearanc e may be similar t o t hat produc ed by loc ulat ed asc it es. Sc alloping of t he liv er, spleen and mesent eric margins by ext rinsic pressure of t he gelat inous masses and f ailure of t he bow el

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2463

16 - Abdominal Wall and Peritoneal Cavity loops t o “ f loat ” t o t he ant erior abdominal w all may be usef ul in dif f erent iat ing pseudomy xoma perit onei f rom asc it es (263). P.1142 P.1143 MRI demonst rat es morphologic c hanges similar t o t hose seen on CT (F ig. 1690) (35).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2464

16 - Abdominal Wall and Peritoneal Cavity F igure 16- 79 Met ast at ic ov arian c arc inoma. A: T ransaxial T 2- w eight ed magnet ic resonanc e image w it h f at suppression show s c y st ic and solid

met ast ases inv olv ing t he c ul- de- sac (ar r ow heads). My omat ous ut erus (U) and rec t um (ar r ow ) are not ed. B: Coronal T 2- w eight ed image w it h f at suppression show s met ast ases bet w een t he ut erus (U) and urinary bladder (B). C : Sagit t al T 2- w eight ed image demonst rat es numerous met ast ases in t he c ul- de- sac (ar r ow heads) and in t he v esic o- ut erine spac e (open ar r ow ).

F igure 16- 80 Met ast at ic c olon c arc inoma. Pelv ic c omput ed t omography demonst rat es asc it es w it h perit oneal t hic kening and enhanc ement in t he c ulde- sac (ar r ow heads).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2465

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 81 Met ast at ic ov arian c arc inoma.A: T ransaxial c omput ed t omography show s asc it es w it h nodular t hic kening of t he perit oneum (ar r ow s) and t umor implant s in t he Morison pouc h (ar r ow heads), t he lesser sac (open ar r ow ), and along t he f alc if orm ligament (w hit e ar r ow ).B: Coronal ref ormat t ed image show s t umor implant s in t he right parac olic gut t er (ar r ow s) and along t he perit oneal surf ac e of t he diaphragm (ar r ow head).

Lymphatic Dissemination Ly mphat ic ext ension play s a minor role in t he int raperit oneal disseminat ion of met ast at ic c arc inoma (181) but is t he primary mode of spread of ly mphoma t o mesent eric ly mph nodes. At t he t ime of present at ion, approximat ely 50% of pat ient s w it h non- Hodgkin ly mphoma hav e mesent eric ly mph node inv olv ement , w hereas only 5% of pat ient s w it h Hodgkin's disease hav e mesent eric disease at present at ion (87). Ident if ic at ion of mesent eric ly mph node disease is ext remely import ant as it almost alw ay s indic at es t he need f or c hemot herapy , somet imes in c ombinat ion w it h radiat ion t herapy (158). Americ an Burkit t ly mphoma is a B- c ell ly mphoma, primarily af f ec t ing c hildren and y oung adult s, t hat usually produc es bulky ext ranodal t umors in t he abdomen (90). On CT t he appearanc e of mesent eric ly mph node inv olv ement by ly mphoma ranges f rom small round or ov al masses w it hin t he mesent eric f at t o large c onf luent masses displac ing adjac ent bow el loops (26,159,315) (F ig. 16- 91). Large c onf luent masses of ly mphomat ous nodes may surround t he superior mesent eric art ery and v eins, produc ing a “ sandw ic h- like” appearanc e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2466

16 - Abdominal Wall and Peritoneal Cavity (109,195) (F ig. 16- 92). Af t er radiat ion or c ombined radiat ion and c hemot herapy P.1144 t reat ment of non- Hodgkin ly mphoma, peripheral c urv ilinear c alc if ic at ions may be seen in t he mesent eric masses (43). When ly mphoma disseminat es t o perit oneal surf ac es ot her t han t he mesent ery (perit oneal ly mphomat osis), t he CT appearanc e may be indist inguishable f rom t hat of met ast at ic c arc inoma (145) (F ig. 16- 93). Pat ient s w it h AIDS- relat ed ly mphoma of t en present w it h

more adv anc ed disease (209). Oc c asionally , t he earliest CT sign of mesent eric ly mphoma is an inc reased number of normal size (less t han 1 c m) ly mph nodes w it hin t he mesent ery . How ev er, mild mesent eric ly mphadenopat hy is a nonspec if ic f inding and does not alw ay s represent ly mphoma. Primary mesent eric adenit is c onsist s of right sided mesent eric ly mph node enlargement (equal t o or great er t han 5 mm) w it hout ident if iable ac ut e inf lammat ory proc ess or w it h only mild w all t hic kening of t he t erminal ileum (171,237) (F ig. 16- 94). P.1145 P.1146 Ot her nonneoplast ic c auses of mesent eric ly mphadenopat hy inc lude inf ilt rat iv e and inf lammat ory disease suc h as Crohn disease (63), sarc oidosis, Whipple disease (163,245), c eliac disease (135), giardiasis, t uberc ulous perit onit is (120), My c obac t er ium av ium -int r ac ellular e inf ec t ion (208), mast oc y t osis (63), and ac quired immune def ic ienc y sy ndrome (AIDS) (194,208). Rarely , mesent eric ly mph nodes assoc iat ed w it h c eliac disease c an undergo c av it at ion and appear as f luid or f at at t enuat ion mesent eric masses (“ mesent eric c av it ary ly mph node sy ndrome” ) (34). Ident if ic at ion of enlarged mesent eric ly mph nodes c ont aining f at - f luid lev els allow s an imaging- spec if ic diagnosis (226,241).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2467

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 82 Mesent eric ly mphadenopat hy in a pat ient w it h c hronic ly mphoc y t ic leukemia.A, B: Cont rast - enhanc ed c omput ed t omography show s mult iple large disc ret e mesent eric masses t hat surround t he superior mesent eric v essels. Not e splenic enlargement .

F igure 16- 83 Perit oneal ly mphoma. Mult iple sof t t issue nodules inv olv e t he great er oment um (ar r ow heads) in t his pat ient w it h non- Hodgkin ly mphoma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2468

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 84 T w o pat ient s w it h met ast at ic c olon c arc inoma. T ransaxial c omput ed t omography image (A) and v olume rendered c oronal image (B) show a low at t enuat ion mass (ar r ow ) w it h punc t uat e c alc if ic at ions at t he root of t he small bow el mesent ery t hat enc ases t he superior mesent eric art ery (ar r ow head).

F igure 16- 85 Mesent eric met ast asis. T 1- w eight ed gradient ec ho magnet ic resonanc e image w it h f at suppression ac quired af t er int rav enous administ rat ion of gadolinium- c helat e show s a rim- enhanc ing mass (ar r ow ) in t his pat ient w it h c olon c arc inoma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2469

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 86 Perit oneal and mesent eric met ast ases f rom c olon c arc inoma. Cont rast - enhanc ed c omput ed t omography demonst rat es asc it es w it h dif f use perit oneal t hic kening (ar r ow s), oment al implant s (ar r ow heads), and mesent eric inf ilt rat ion. T he mesent eric v asc ular bundles are t hic kened, and t he mesent ery has a rigid appearanc e.

F igure 16- 87 Pseudomy xoma perit onei.A, B: Cont rast - enhanc ed c omput ed t omography show s large c onf luent sept at ed c y st ic masses t hat c ause sc alloping of t he margins of t he liv er and spleen. Sev eral of t he masses c ont ain punc t uat e c alc if ic at ions.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2470

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 88 Pseudomy xoma perit onei. Cont rast - enhanc ed c omput ed t omography image show s ext ensiv e perit oneal inv olv ement by sept at e c y st ic masses t hat sc allop t he liv er margin.

F igure 16- 89 Pseudomy xoma perit onei. Conf luent low - at t enuat ion sept at ed masses (M) sc allop t he liv er margin and displac e bow el.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2471

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 90 Pseudomy xoma perit onei. Coronal T 2- w eight ed magnet ic resonanc e image demonst rat es mult iple c onf luent high signal int ensit y perisplenic c y st ic masses (ar r ow s) t hat c ause sc alloping of t he splenic margin. Also not e t he perihepat ic and subhepat ic t umor implant s (ar r ow heads).

Embolic Metastases T umor emboli may be spread v ia t he mesent eric art eries t o t he ant imesent eric border of bow el w here t he c ells implant and subsequent ly grow int o int ramural t umor nodules (184). On CT , t hese embolic met ast ases may produc e t hic kening of t he mesent eric leav es or f oc al bow el w all t hic kening, oc c asionally w it h rec ognizable ulc erat ion. T he most c ommon neoplasms t o spread in t his manner are melanoma (139,178) and c arc inoma of t he breast or lung (F ig. 16- 95).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2472

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 91 Burkit t ly mphoma. Cont rast - enhanc ed c omput ed t omography show s a large c onf luent ly mph node mass w it hin t he small bow el mesent ery enc asing t he mesent eric v essels.

F igure 16- 92 Non- Hodgkin ly mphoma. Large c onf luent mesent eric ly mph node masses surround t he superior mesent eric v essels produc ing a “ sandw ic hlike” appearanc e.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2473

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 93 Perit oneal ly mphomat osis. Comput ed t omography show s asc it es and dif f use inf ilt rat ion of t he great er oment um (arrow heads) produc ing an “ oment al c ake.” Not e t he low at t enuat ion hepat ic mass and bilat eral renal masses in t his pat ient w it h dif f use disseminat ion of non- Hodgkin ly mphoma.

F igure 16- 94 Mesent eric adenit is. Comput ed t omography show s sev eral enlarged ly mph nodes in t he ileoc olic region of t he mesent ery (ar r ow s). A normal appendix w as seen on low er pelv ic images.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2474

16 - Abdominal Wall and Peritoneal Cavity

F igure 16- 95 Met ast at ic breast c arc inoma. Comput ed t omography image show s a large mass (M) inv olv ing t he w all of a small bow el loop (ar r ow heads).

P.1147

REFERENCES 1. Ac kerman L. At las of t um or pat hology . F asc ic les 23 and 24: T um or s of t he r et r oper it oneum m esent er y and om ent um . Washingt on, DC: Armed F orc es Inst it ut e of Pat hology ; 1954. 2. Agarw al A, Y eh BM, Breiman RS, et al. Perit oneal c alc if ic at ion: c auses and dist inguishing f eat ures on CT . AJR Am J Roent genol. 2004;182:441–445. 3. Aguirre D, Casola G, Sirlin C. Abdominal w all hernias: MDCT f indings. AJR Am J Roent genol. 2004;183:681–690. 4. Akhan O, Pringot J. Imaging of abdominal t uberc ulosis. Eur Radiol. 2002;12:312–323. 5. Allen HA 3rd, Vic k CW, Messmer JM, et al. Dif f use mesent eric amy loidosis: CT , sonographic , and pat hologic f indings. J Com put Assist T om ogr . 1985;9:196–198. 6. Alt emeier WA, Culbert son WR, F ullen WD, Shook CD. Int ra- abdominal absc esses. Am J Sur g. 1973;125:70–79. 7. Ambroset t i P, Jenny A, Bec ker C, et al. Ac ut e lef t c olonic div ert ic ulit is–c ompared perf ormanc e of c omput ed t omography and w at ersoluble c ont rast enema: prospec t iv e ev aluat ion of 420 pat ient s. Dis Colon Rec t um . 2000;43:1363–1367.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2475

16 - Abdominal Wall and Peritoneal Cavity

8. Arai K, Makino H, Morioka T , et al. Enhanc ement of asc it es on MRI f ollow ing int rav enous administ rat ion of Gd- DT PA. J Com put Assist T om ogr . 1993;17:617–622. 9. Arenas AP, Sanc hez LV, Albillos JM, et al. Direc t disseminat ion of pat hologic abdominal proc esses t hrough perihepat ic ligament s: ident if ic at ion w it h CT . Radiogr aphic s 1994;14:515–528. 10. Aronberg DJ, St anley RJ, Lev it t RG, et al. Ev aluat ion of abdominal absc ess w it h c omput ed t omography . J Com put Assist T om ogr . 1978;2:384–387. 11. Asc her SM, Agraw al R, Bis KG, et al. Endomet riosis: appearanc e and det ec t ion w it h c onv ent ional and c ont rast - enhanc ed f at - suppressed spin- ec ho t ec hniques. J Magn Reson Im aging. 1995;5: 251–257. P.1148 12. Auh Y H, Lim JH, Kim KW, et al. Loc ulat ed f luid c ollec t ions in hepat ic f issures and rec esses: CT appearanc e and pot ent ial pit f alls. Radiogr aphic s 1994;14:529–540. 13. Azizi L, Balu M, Belkac em A, et al. MRI f eat ures of mesent eric desmoid t umors in f amilial adenomat ous poly posis. AJR Am J Roent genol. 2005;184(4):1128–1235. 14. Bader T R, Semelka RC, Chiu VC, et al. MRI of c arc inoid t umors: spec t rum of appearanc es in t he gast roint est inal t rac t and liv er. J Magn Reson Im aging. 2001;14:261–269. 15. Baker ME, Weinert h JL, Andriani RT , et al. Lumbar hernia: diagnosis by CT . AJR Am J Roent genol. 1987;148:565–567. 16. Balt hazar EJ, F reeny PC, v anSonnenberg E. Imaging and int erv ent ion in ac ut e panc reat it is. Radiology 1994;193:297–306. 17. Balt hazar EJ, Lef kow it z RA. Lef t - sided oment al inf arc t ion w it h assoc iat ed oment al absc ess: CT diagnosis. J Com put Assist T om ogr . 1993;17:379–381. 18. Balt hazar EJ, Subramany am BR, Megibow A. Spigelian hernia: CT and ult rasonography diagnosis. Gast r oint est Radiol. 1984;9: 81–84. 19. Balt hazar EJ. CT diagnosis and st aging of ac ut e panc reat it is. Radiol Clin Nor t h Am . 1989;27:19–37. 20. Barakos JA, Jef f rey RB Jr, F ederle MP, et al. CT in t he management of periappendic eal absc ess. AJR Am J Roent genol. 1986;146: 1161–1164. 21. Baron RL, Lee JK. Mesent eric desmoid t umors: sonographic and c omput edt omographic appearanc e. Radiology 1981;140:777–779. 22. Bec ht old RE, Chen MY , Loggie BW, et al. CT appearanc e of disseminat ed perit oneal adenomuc inosis. Abdom Im aging. 2001;26: 406–410.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2476

16 - Abdominal Wall and Peritoneal Cavity 23. Bec ker G, Hess CF , Grund KE, et al. Abdominal w all met ast asis f ollow ing perc ut aneous endosc opic gast rost omy . Suppor t Car e Canc er . 1995;3:313–316. 24. Bergst rom M, Eric son K, Lev ander B, et al. Variat ion w it h t ime of t he at t enuat ion v alues of int rac ranial hemat omas. J Com put Assist T om ogr . 1977;1:57–63. 25. Berna JD, Garc ia- Medina V, Guirao J, et al. Rec t us sheat h hemat oma: diagnost ic c lassif ic at ion by CT . Abdom Im aging. 1996;21:62–64. 26. Bernardino ME, Jing BS, Wallac e S. Comput ed t omography diagnosis of mesent eric masses. AJR Am J Roent genol. 1979;132: 33–36. 27. Bis KG, Vrac hliot is T G, Agraw al R, et al. Pelv ic endomet riosis: MR imaging spec t rum w it h laparosc opic c orrelat ion and diagnost ic pit f alls. Radiogr aphic s 1997;17:639–655.

28. Bradley WG, Jr, Sc hmidt PG. Ef f ec t of met hemoglobin f ormat ion on t he MR appearanc e of subarac hnoid hemorrhage. Radiology 1985;156:99–103. 29. Brasf ield RD, Das Gupt a T K. Desmoid t umors of t he ant erior abdominal w all. Sur ger y 1969;65:241–246. 30. Bree RL, Sc hw ab RE. Cont ribut ion of mesent eric f at t o unsat isf ac t ory abdominal and pelv ic ult rasonography . Radiology 1981;140: 773–776. 31. Brooks AP, Reznek RH, Nugent K, et al. CT appearanc es of desmoid t umours in f amilial adenomat ous poly posis: f urt her observ at ions. Clin Radiol. 1994;49:601–607. 32. Brow n JJ, v anSonnenberg E, Gerber KH, et al. Magnet ic resonanc e relaxat ion t imes of perc ut aneously obt ained normal and abnormal body f luids. Radiology 1985;154:727–731. 33. Buhr J, Hurt gen M, Heinric hs CM, et al. [Implant at ion met ast ases f ollow ing laparosc opic c holec y st ec t omy in gallbladder c arc inoma]. Dt sc h Med Woc hensc hr . 1996;121:57–61; disc ussion 61–62. 34. Burrell HC, T resc oli C, Chow K, et al. Case report : mesent eric ly mph node c av it at ion, an unusual c omplic at ion of c oeliac disease. Br J Radiol. 1994;67:1139–1140. 35. Buy JN, Malbec L, Ghossain MA, et al. Magnet ic resonanc e imaging of pseudomy xoma perit onei. Eur J Radiol. 1989;9:115–118. 36. By dder GM, Kreel L. At t enuat ion v alues of f luid c ollec t ions w it hin t he abdomen. J Com put Assist T om ogr . 1980;4:145–150. 37. Callen PW. Comput ed t omographic ev aluat ion of abdominal and pelv ic absc esses. Radiology 1979;131:171–175.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2477

16 - Abdominal Wall and Peritoneal Cavity

38. Caseiro- Alv es F , Gonc alo M, Abraul E, et al. Induc ed pneumoperit oneum in CT ev aluat ion of perit oneal c arc inomat osis. Abdom Im aging. 1995;20(1):52–55; disc ussion 6–7. 39. Casillas J, Sais GJ, Grev e JL, et al. Imaging of int ra- and ext raabdominal desmoid t umors. Radiogr aphic s 1991;11:959–968. 40. Ceut eric k L, Baert AL, Marc hal G, et al. CT diagnosis of primary t orsion of great er oment um. J Com put Assist T om ogr . 1987;11: 1083–1084. 41. Charnsangav ej C, DuBrow RA, Varma DG, et al. CT of t he mesoc olon. Part 1. Anat omic c onsiderat ions. Radiogr aphic s 1993;13: 1035–1045. 42. Charnsangav ej C, Dubrow RA, Varma DG, et al. CT of t he mesoc olon. Part 2. Pat hologic c onsiderat ions. Radiogr aphic s 1993;13: 1309–1322. 43. Cheng J, Cast ellino RA. Post - t reat ment c alc if ic at ion of mesent eric nonHodgkin ly mphoma: CT f indings. J Com put Assist T om ogr . 1989;13:64–66. 44. Chiou SY , Sheu MH, Wang JH, et al. Perit oneal serous papillary c arc inoma: a reappraisal of CT imaging f eat ures and lit erat ure rev iew . Abdom Im aging. 2003;28:815–819. 45. Chopra S, Dodd GD 3rd, Chint apalli KN, et al. Mesent eric , oment al, and ret roperit oneal edema in c irrhosis: f requenc y and spec t rum of CT f indings. Radiology 1999;211:737–342. 46. Chopra S, Laurie LR, Chint apalli KN, et al. Primary papillary serous c arc inoma of t he perit oneum: CT - pat hologic c orrelat ion. J Com put Assist T om ogr . 2000;24:395–399. 47. Chouli M, Viala J, Dromain C, et al. Int ra- abdominal desmoplast ic small round c ell t umors: CT f indings and c linic opat hologic al c orrelat ions in 13 c ases. Eur J Radiol. 2005;54: 438–442.[D7] 48. Ciroc c o WC, Sc hw art zman A, Golub RW. Abdominal w all rec urrenc e af t er laparosc opic c olec t omy f or c olon c anc er. Sur ger y 1994;116:842–846. 49. Coakley F V, Choi PH, Gougout as CA, et al. Perit oneal met ast ases: det ec t ion w it h spiral CT in pat ient s w it h ov arian c anc er. Radiology 2002;223:495–499. 50. Cohen JM, Weinreb JC, Marav illa KR. F luid c ollec t ions in t he int raperit oneal and ext raperit oneal spac es: c omparison of MR and CT . Radiology 1985;155:705–708. 51. Cohen WN, Seidelmann F E, Bry an PJ. Comput ed t omography of loc alized adipose deposit s present ing as t umor masses. AJR Am J Roent genol. 1977;128:1007–1111.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2478

16 - Abdominal Wall and Peritoneal Cavity 52. Coll DM, Mey er JM, Mader M, et al. Imaging appearanc es of Sist er Mary Joseph nodule. Br J Radiol. 1999;72(864): 1230–1233. 53. Coode PE, Mc Guinness F E, Raw as MM, et al. Dif f use lipomat osis inv olv ing t he t horac ic and abdominal w all: CT f eat ures. J Com put Assist T om ogr . 1991;15:341–343. 54. Cooper C, Jef f rey RB, Silv erman PM, et al. Comput ed t omography of oment al pat hology . J Com put Assist T om ogr . 1986;10:62–66. 55. Cooper C, Silv erman PM, Dav ros WJ, et al. Delay ed c ont rast enhanc ement of asc it ic f luid on CT : f requenc y and signif ic anc e. AJR Am J Roent genol. 1993;161:787–790. 56. Coumbaras M, Chopier J, Massiani MA, et al. Dif f use mesent eric and oment al inf ilt rat ion by amy loidosis w it h oment al c alc if ic at ion mimic king abdominal c arc inomat osis. Clin Radiol. 2001;56: 674–676. 57. Cry er PE, Kissane J. Inf ilt rat iv e gast roint est inal disease. Am J Med. 1974;57:127–134.

58. Dac hman AH, Lic ht enst ein JE, F riedman AC. Muc oc ele of t he appendix and pseudomy xoma perit onei. AJR Am J Roent genol. 1985;144:923–999. 59. Dahlene DH Jr, St anley RJ, Koehler RE, et al. Abdominal t uberc ulosis: CT f indings. J Com put Assist T om ogr . 1984;8:443–445. 60. Daniel O. T he dif f erent ial diagnosis of malignant disease of t he perit oneum. Br J Sur g. 1951;39:147–156. 61. Daskalogiannaki M, Voloudaki A, Prassopoulos P, et al. CT ev aluat ion of mesent eric pannic ulit is: prev alenc e and assoc iat ed diseases. AJR Am J Roent genol. 2000;174:427–431. 62. DeMeo JH, F ulc her AS, Aust in RF Jr. Anat omic CT demonst rat ion of t he perit oneal spac es, ligament s, and mesent eries: normal and pat hologic proc esses. Radiogr aphic s 1995;15:755–770. 63. Deut c h SJ, Sandler MA, Alpern MB. Abdominal ly mphadenopat hy in benign diseases: CT det ec t ion. Radiology 1987;163: 335–338. 64. Dobrin PB, Gully PH, Greenlee HB, et al. Radiologic diagnosis of an int raabdominal absc ess. Do mult iple t est s help? Ar c h Sur g. 1986;121:41–46. P.1149 65. Dodds WJ, F oley WD, Law son T L, et al. Anat omy and imaging of t he lesser perit oneal sac . AJR Am J Roent genol. 1985;144: 567–575. 66. Dooms GC, F isher MR, Hric ak H, et al. MR imaging of int ramusc ular hemorrhage. J Com put Assist T om ogr . 1985;9:908–913.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2479

16 - Abdominal Wall and Peritoneal Cavity 67. Eggesbo HB, Jac obsen T , Kolmannskog F , et al. Diagnosis of ac ut e lef t sided c olonic div ert ic ulit is by t hree radiologic al modalit ies. Ac t a Radiol. 1998;39:315–321. 68. Emby D, Aoun G. CT t ec hnique f or suspec t ed ant erior abdominal w all hernia. AJR Am J Roent genol. 2003;181:431–433. 69. Emory T S, Monihan JM, Carr NJ, et al. Sc lerosing mesent erit is, mesent eric pannic ulit is and mesent eric lipody st rophy : a single ent it y ? Am J Sur g Pat hol. 1997;21:392–398. 70. Epst ein BM, Mann JH. CT of abdominal t uberc ulosis. AJR Am J Roent genol. 1982;139:861–866. 71. Epst ein LI, Lempke RE. Primary idiopat hic segment al inf arc t ion of t he great er oment um: c ase report and c ollec t iv e rev iew of t he lit erat ure. Ann Sur g. 1968;167:437–443. 72. F axon H. Subphrenic absc ess. N Engl J Med. 1940;222:289–299.

73. F ederle MP, Chun G, Jef f rey RB, Ray or R. Comput ed t omographic f indings in bow el inf arc t ion. AJR Am J Roent genol. 1984;142:91–95. 74. F ederle MP, Jef f rey RB Jr. Hemoperit oneum st udied by c omput ed t omography . Radiology 1983;148:187–192. 75. F erreiros J, Gomez Leon N, Mat a MI, et al. Comput ed t omography in abdominal Cast leman's disease. J Com put Assist T om ogr . 1989;13:433–436. 76. F rager DH, Goldman M, Benev ent ano T C. Comput ed t omography in Crohn disease. J Com put Assist T om ogr . 1983;7:819–824. 77. F ukuda T , Sakamot o I, Kohzaki S, et al. Spont aneous rec t us sheat h hemat omas: c linic al and radiologic al f eat ures. Abdom Im aging. 1996;21:58–61. 78. F urukaw a T , Ueda J, T akahashi S, et al. Perit oneal serous papillary c arc inoma: radiologic al appearanc e. Abdom Im aging. 1999;24: 78–81. 79. Galani E, Marx GM, St eer CB, et al. Pseudomy xoma perit onei: t he “ c ont rov ersial” disease. Int J Gy nec ol Canc er . 2003;13:413–418. 80. Garber SJ, Shaw DG. Case report : t he ult rasound and c omput ed t omography appearanc e of mesent eric Cast leman disease. Clin Radiol. 1991;43:429–430. 81. Gedgaudas RK, Ric e RP. Radiologic al ev aluat ion of c omplic at ed panc reat it is. Cr it Rev Diagn Im aging. 1981;15:319–367. 82. Gerald WL, Miller HK, Bat t if ora H, et al. Int ra- abdominal desmoplast ic small round- c ell t umor. Report of 19 c ases of a dist inc t iv e t y pe of high- grade

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2480

16 - Abdominal Wall and Peritoneal Cavity poly phenot y pic malignanc y af f ec t ing y oung indiv iduals. Am J Sur g Pat hol. 1991;15:499–513. 83. Gerzof SG, Johnson WC, Robbins AH, et al. Expanded c rit eria f or perc ut aneous absc ess drainage. Ar c h Sur g. 1985;120:227–232. 84. Ghahremani GG, Jimenez MA, Rosenf eld M, et al. CT diagnosis of oc c ult inc isional hernias. AJR Am J Roent genol. 1987;148: 139–142. 85. Ghahremani GG, Whit e EM, Hof f F , et al. Appendic es epiploic ae of t he c olon: radiologic and pat hologic f eat ures. Radiogr aphic s 1992;12:59–77. 86. Gleeson NC, Nic osia SV, Mark JE, et al. Abdominal w all met ast ases f rom

ov arian c anc er af t er laparosc opy . Am J Obst et Gy nec ol. 1993;169:522–523. 87. Gof f inet DR, Cast ellino RA, Kim H, et al. St aging laparot omies in unselec t ed prev iously unt reat ed pat ient s w it h non- Hodgkin's ly mphomas. Canc er 1973;32:672–681. 88. Goldberg HI, Gore RM, Margulis AR, et al. Comput ed t omography in t he ev aluat ion of Crohn disease. AJR Am J Roent genol. 1983;140: 277–282. 89. Gomori JM, Grossman RI, Goldberg HI, et al. Int rac ranial hemat omas: imaging by high- f ield MR. Radiology 1985;157:87–93. 90. Goodman P, Rav al B. CT of t he abdominal w all. AJR Am J Roent genol. 1990;154:1207–1211. 91. Gore RM, Callen PW, F illy RA. Lesser sac f luid in predic t ing t he et iology of asc it es: CT f indings. AJR Am J Roent genol. 1982;139:71–74. 92. Gore RM, Marn CS, Kirby DF , et al. CT f indings in ulc erat iv e, granulomat ous, and indet erminat e c olit is. AJR Am J Roent genol. 1984;143:279–284. 93. Goss C. Gr ay 's Anat om y of t he Hum an Body . 29t h Americ an ed. Philadelphia: Lea and F ebiger; 1973. 94. Gougout as CA, Siegelman ES, Hunt J, et al. Pelv ic endomet riosis: v arious manif est at ions and MR imaging f indings. AJR Am J Roent genol. 2000;175:353–358. 95. Grendell JH, Oc kner RK. Mesent eric v enous t hrombosis. Gast r oent er ology 1982;82:358–372. 96. Guermazi A, de Kerv iler E, Cazals- Hat em D, et al. Imaging f indings in pat ient s w it h my elof ibrosis. Eur Radiol. 1999;9:1366–1375. 97. Guest PJ, Reznek RH, Selleslag D, et al. Perit oneal mesot helioma: t he role of c omput ed t omography in diagnosis and f ollow up. Clin Radiol. 1992;45:79–84.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2481

16 - Abdominal Wall and Peritoneal Cavity 98. Gupt a S, Shirahat t i RG, Anand J. CT f indings of an abdominal c oc oon. AJR Am J Roent genol. 2004;183:1658–1660.

99. Ha HK, Jung JI, Lee MS, et al. CT dif f erent iat ion of t uberc ulous perit onit is and perit oneal c arc inomat osis. AJR Am J Roent genol. 1996;167:743–748. 100. Haaga JR, Alf idi RJ, Hav rilla T R, et al. CT det ec t ion and aspirat ion of abdominal absc esses. AJR Am J Roent genol. 1977;128:465–474. 101. Haf ner M, Nov ac ek G, Herbst F , et al. Giant benign c y st ic mesot helioma: a c ase report and rev iew of lit erat ure. Eur J Gast r oent er ol Hepat ol. 2002;14:77–80. 102. Hahn PF , Saini S, St ark DD, et al. Int raabdominal hemat oma: t he c onc ent ric - ring sign in MR imaging. AJR Am J Roent genol. 1987;148:115–119. 103. Halber MD, Daf f ner RH, Morgan CL, et al. Int raabdominal absc ess: c urrent c onc ept s in radiologic ev aluat ion. AJR Am J Roent genol. 1979;133:9–13. 104. Halliday P, Halliday JH. Subphrenic absc ess: a st udy of 241 pat ient s at t he Roy al Princ e Edw ard Hospit al, 1950–73. Br J Sur g. 1976;63:352–366. 105. Halv orsen RA Jr, Panushka C, Oakley GJ, et al. Int raperit oneal c ont rast mat erial improv es t he CT det ec t ion of perit oneal met ast ases. AJR Am J Roent genol. 1991;157:37–40. 106. Hamric k- T urner JE, Chiec hi MV, Abbit t PL, et al. Neoplast ic and inf lammat ory proc esses of t he perit oneum, oment um, and mesent ery : diagnosis w it h CT . Radiogr aphic s 1992;12:1051–1068. 107. Haney PJ, Whit ley NO. CT of benign c y st ic abdominal masses in c hildren. AJR Am J Roent genol. 1984;142:1279–1281. 108. Hanson RD, Hunt er T B. T uberc ulous perit onit is: CT appearanc e. AJR Am J Roent genol. 1985;144:931–932. 109. Hardy SM. T he sandw ic h sign. Radiology 2003;226:651–652. 110. Hay ashi S, Oy ama K, Hirakaw a K, et al. [Mesent eric pannic ulit is—c ase report and it s radiologic al diagnosis inc luding CT (aut hor's t ranslat ion)]. Rinsho Hoshasen. 1982;27:143–146. 111. Healy JC, Reznek RH, Clark SK, et al. MR appearanc es of desmoid t umors in f amilial adenomat ous poly posis. AJR Am J Roent genol. 1997;169:465–472. 112. Healy ME, T eng SS, Moss AA. Urinif erous pseudoc y st : c omput ed t omographic f indings. Radiology 1984;153:757–762. 113. Heiken JP, Brink JA, Sagel SS. Helic al CT : abdominal applic at ions. Radiogr aphic s 1994;14:919–924.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2482

16 - Abdominal Wall and Peritoneal Cavity 114. Hibbeln JF , Wehmueller MD, Wilbur AC. Chy lous asc it es: CT and ult rasound appearanc e. Abdom Im aging. 1995;20:138–140. 115. Hort on KM, Law ler LP, F ishman EK. CT f indings in sc lerosing mesent erit is (pannic ulit is): spec t rum of disease. Radiogr aphic s 2003;23:1561–1567. 116. Houer A, Ry gaard H, Jess P. CT in t he diagnosis of abdominal w all hernias: a preliminary st udy . Eur Radiol. 1997;7:1416–1418. 117. Hudson T M, Vandergriend RA, Springf ield DS, et al. Aggressiv e f ibromat osis: ev aluat ion by c omput ed t omography and angiography . Radiology 1984;150:495–501. 118. Hui GC, Amaral J, St ephens D, et al. Gas dist ribut ion in int raabdominal and pelv ic absc esses on CT is assoc iat ed w it h drainabilit y . AJR Am J Roent genol. 2005;184:915–919.

119. Hulnic k DH, Megibow AJ, Balt hazar EJ, Naidic h DP, Bosniak MA. Comput ed t omography in t he ev aluat ion of div ert ic ulit is. Radiology 1984;152:491–495. 120. Hulnic k DH, Megibow AJ, Naidic h DP, et al. Abdominal t uberc ulosis: CT ev aluat ion. Radiology 1985;157:199–204. 121. Ianora A, Midiri M, Vinc i R, et al. Abdominal w all hernias: imaging w it h spiral CT . Eur Radiol. 2000;10:914–919. P.1150 122. Ic hikaw a T , Koy ama A, F ujimot o H, et al. Abdominal w all desmoid mimic king int ra- abdominal mass: MR f eat ures. Magn Reson Im aging. 1994;12:541–544. 123. Ishida H, Ishida J. Primary t umours of t he great er oment um. Eur Radiol. 1998;8:1598–601. 124. Ishida J, Ishida H, Konno K, et al. Primary leiomy osarc oma of t he great er oment um. J Clin Gast r oent er ol. 1999;28:167–170. 125. Jac obs JE, Birnbaum BA, Siegelman ES. Het erot opic ossif ic at ion of midline abdominal inc isions: CT and MR imaging f indings. AJR Am J Roent genol. 1996;166:579–584. 126. Jac quet P, Av erbac h AM, Jac quet N. Abdominal w all met ast asis and perit oneal c arc inomat osis af t er laparosc opic - assist ed c olec t omy f or c olon c anc er. Eur J Sur g Onc ol. 1995;21:568–570. 127. Jaf f e T , O'Connell M, Harris J, et al. MDCT of abdominal w all hernias: is t here a role f or Valsalv a's maneuv er? AJR Am J Roent genol. 2005;184:847–851.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2483

16 - Abdominal Wall and Peritoneal Cavity 128. Jaques P, Mauro M, Saf rit H, et al. CT f eat ures of int raabdominal absc esses: predic t ion of suc c essf ul perc ut aneous drainage. AJR Am J Roent genol. 1986;146:1041–1045. 129. Jat zko G, Lisborg P, Horn M, et al. [Abdominal w all implant at ion met ast asis 2 y ears af t er apparent ly unev ent f ul laparosc opic c holec y st ec t omy ]. Chir ur g 1994;65:812–814.

130. Jef f rey R. Comput ed t omography of t he perit oneal c av it y and mesent ery . In: Moss AA, Gansu G, Genant HK, eds. Com put ed t om ogr aphy of t he body . Philadelphia: WB Saunders; 1983. 131. Jef f rey RB Jr, T olent ino CS, F ederle MP, et al. Perc ut aneous drainage of periappendic eal absc esses: rev iew of 20 pat ient s. AJR Am J Roent genol. 1987;149:59–62. 132. Jef f rey RB Jr. CT demonst rat ion of perit oneal implant s. AJR Am J Roent genol. 1980;135:323–326. 133. Jef f rey RB, F ederle MP, Laing F C. Comput ed t omography of mesent eric inv olv ement in f ulminant panc reat it is. Radiology 1983;147:185–188. 134. Johnson LA, Longac re T A, Whart on KA Jr, et al. Mult iple mesent eric ly mphat ic c y st s: an unusual f eat ure of mesent eric pannic ulit is (sc lerosing mesent erit is). J Com put Assist T om ogr . 1997;21:103–105. 135. Jones B, Bay less T M, F ishman EK, et al. Ly mphadenopat hy in c eliac disease: c omput ed t omographic observ at ions. AJR Am J Roent genol. 1984;142:1127–1132. 136. Kaiser AM, Jiang JK, Lake JP, et al. T he management of c omplic at ed div ert ic ulit is and t he role of c omput ed t omography . Am J Gast r oent er ol. 2005;100:910–917. 137. Kat z ME, Heiken JP, Glazer HS, et al. Int raabdominal pannic ulit is: c linic al, radiographic , and CT f eat ures. AJR Am J Roent genol. 1985;145:293–296. 138. Kaw ashima A, F ishman EK, Hruban RH, et al. Mesent eric pannic ulit is present ing as a mult iloc ular c y st ic mesent eric mass: CT and MR ev aluat ion. Clin Im aging. 1993;17:112–116. 139. Kaw ashima A, F ishman EK, Kuhlman JE, et al. CT of malignant melanoma: pat t erns of small bow el and mesent eric inv olv ement . J Com put Assist T om ogr . 1991;15:570–574. 140. Kebapc i M, Vardareli E, Adapinar B, et al. CT f indings and serum c a 125 lev els in malignant perit oneal mesot helioma: report of 11 new c ases and rev iew of t he lit erat ure. Eur Radiol. 2003;13: 2620–2626.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2484

16 - Abdominal Wall and Peritoneal Cavity 141. Kebapc i M, Y alc in OT , Dundar E, et al. Comput ed t omography f indings of

primary serous papillary c arc inoma of t he perit oneum in w omen. Eur J Gy naec ol Onc ol. 2003;24:552–556. 142. Kerber GW, Greenberg M, Rubin JM. Comput ed t omography ev aluat ion of loc al and ext raint est inal c omplic at ions of Crohn's disease. Gast r oint est Radiol. 1984;9:143–148. 143. Kim HC, Lee JM, Kim SH, et al. Primary gast roint est inal st romal t umors in t he oment um and mesent ery : CT f indings and pat hologic c orrelat ions. AJR Am J Roent genol. 2004;182:1463–1467. 144. Kim T , Murakami T , Oi H, et al. CT and MR imaging of abdominal liposarc oma. AJR Am J Roent genol. 1996;166:829–833. 145. Kim Y , Cho O, Song S, et al. Perit oneal ly mphomat osis: CT f indings. Abdom Im aging. 1998;23:87–90. 146. Kirc her MF , Rhea JT , Kihic zak D, et al. F requenc y , sensit iv it y , and spec if ic it y of indiv idual signs of div ert ic ulit is on t hin- sec t ion helic al CT w it h c olonic c ont rast mat erial: experienc e w it h 312 c ases. AJR Am J Roent genol. 2002;178:1313–1318. 147. Knoc hel JQ, Koehler PR, Lee T G, et al. Diagnosis of abdominal absc esses w it h c omput ed t omography , ult rasound, and 111In leukoc y t e sc ans. Radiology 1980;137:425–432. 148. Koehler PR, Moss AA. Diagnosis of int ra- abdominal and pelv ic absc esses by c omput erized t omography . JAMA 1980;244: 49–52. 149. Korobkin M, Callen PW, F illy RA, et al. Comparison of c omput ed t omography , ult rasonography , and gallium- 67 sc anning in t he ev aluat ion of suspec t ed abdominal absc ess. Radiology 1978;129:89–93. 150. Korobkin M, Moss AA, Callen PW, et al. Comput ed t omography of subc apsular splenic hemat oma. Clinic al and experiment al st udies. Radiology 1978;129:44144–44155. 151. Kosuc u P, Ahmet oglu A, Cobanoglu U, et al. Mesent eric inv olv ement in neurof ibromat osis t y pe 1: CT and MRI f indings in t w o c ases. Abdom Im aging. 2003;28:822–826. 152. Kront hal AJ, Kang Y S, F ishman EK, et al. MR imaging in sc lerosing mesent erit is. AJR Am J Roent genol. 1991;156:517–519. 153. Law dahl RB, Moss CN, Van Dy ke JA. Inf erior lumbar (Pet it 's) hernia. AJR Am J Roent genol. 1986;147:744–745.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2485

16 - Abdominal Wall and Peritoneal Cavity 154. Lee EY , Heiken JP, Huet t ner PC. Lat e rec urrenc e of malignant melanoma present ing as perit oneal “ c arc inomat osis.” Abdom Im aging. 2003;28:284–286.

155. Lee GH, Cohen AJ. CT imaging of abdominal hernias. AJR Am J Roent genol. 1993;161:1209–1213. 156. Lee JT , Kim MJ, Y oo KS, et al. Primary leiomy osarc oma of t he great er oment um: CT f indings. J Com put Assist T om ogr . 1991;15: 92–94. 157. Lev ine CD, Pat el UJ, Silv erman PM, Wac hsberg RH. Low at t enuat ion of ac ut e t raumat ic hemoperit oneum on CT sc ans. AJR Am J Roent genol. 1996;166:1089–1093. 158. Lev it t R. Abdominal w all and perit oneal c av it y . In: Sagel SS, St anley RJ, eds. Com put ed body t om ogr aphy . New Y ork: Rav en Press; 1983. 159. Lev it t RG, Sagel SS, St anley RJ. Det ec t ion of neoplast ic inv olv ement of t he mesent ery and oment um by c omput ed t omography . AJR Am J Roent genol. 1978;131:835–838. 160. Lev y AD, Cant isani V, Miet t inen M. Abdominal ly mphangiomas: imaging f eat ures w it h pat hologic c orrelat ion. AJR Am J Roent genol. 2004;182:1485–1491. 161. Lew in JR, Pat t erson EA. CT rec ognit ion of spont aneous int raperit oneal hemorrhage c omplic at ing ant ic oagulant t herapy . AJR Am J Roent genol. 1980;134:1271–1272. 162. Lew is VL, Shaf f er HA Jr, Williamson BR. Pseudot umoral lipomat osis of t he abdomen. J Com put Assist T om ogr . 1982;6:79–82. 163. Li DK, Rennie CS. Abdominal c omput ed t omography in Whipple's disease. J Com put Assist T om ogr . 1981;5:249–252. 164. Lieberman JM, Haaga JR. Comput ed t omography of div ert ic ulit is. J Com put Assist T om ogr . 1983;7:431–433. 165. Lorenz R, Bey er D, Pet ers PE. Det ec t ion of int raperit oneal bile ac c umulat ions: signif ic anc e of ult rasonography , CT , and c holesc int igraphy . Gast r oint est Radiol. 1984;9:213–217. 166. Low R, Alzat e G, Siget i J, et al. Double- c ont rast MR imaging of perit oneal t umors w it h dilut e barium oral c ont rast , int rav enous gadolinium, and breat hhold F MPSPGR imaging. Radiology 1996;201:252. 167. Low R, Barone R, Lac ey C, et al. Perit oneal t umor: MR imaging w it h dilut e oral barium and int rav enous Gadolinium- c ont aining c ont rast agent s c ompared w it h unenhanc ed MR imaging and CT . Radiology 1997;204:513–520.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2486

16 - Abdominal Wall and Peritoneal Cavity

168. Low RN. Gadolinium- enhanc ed MR imaging of liv er c apsule and perit oneum. Magn Reson Im aging Clin N Am . 2001;9: 803–819, v ii. 169. Lubat E, Balt hazar EJ. T he c urrent role of c omput erized t omography in inf lammat ory disease of t he bow el. Am J Gast r oent er ol. 1988;83:107–113. 170. Luc ey BC, St uhlf aut JW, Sot o JA. Mesent eric ly mph nodes: det ec t ion and signif ic anc e on MDCT . AJR Am J Roent genol. 2005;184: 41–44. 171. Mac ari M, Hines J, Balt hazar E, et al. Mesent eric adenit is: CT diagnosis of primary v ersus sec ondary c auses, inc idenc e, and c linic al signif ic anc e in pediat ric and adult pat ient s. AJR Am J Roent genol. 2002;178:853–888. P.1151 172. Magid D, F ishman EK, Jones B, et al. Desmoid t umors in Gardner sy ndrome: use of c omput ed t omography . AJR Am J Roent genol. 1984;142:1141–1145. 173. Mall JC, Kaiser JA. CT diagnosis of splenic lac erat ion. AJR Am J Roent genol. 1980;134:265–269. 174. Mart in DR, Karabulut N, Y ang M, et al. High signal peripanc reat ic f at on f at - suppressed spoiled gradient ec ho imaging in ac ut e panc reat it is: preliminary ev aluat ion of t he prognost ic signif ic anc e. J Magn Reson Im aging. 2003;18:49–58. 175. Mat a JM, Inaraja L, Mart in J, et al. CT f eat ures of mesent eric pannic ulit is. J Com put Assist T om ogr . 1987;11:1021–1023. 176. Mat suoka Y , Oht omo K, It ai Y , et al. Pseudomy xoma perit onei w it h progressiv e c alc if ic at ions: CT f indings. Gast r oint est Radiol. 1992;17:16–18. 177. May es GB, Chuang VP, F isher RG. CT of pseudomy xoma perit onei. AJR Am J Roent genol. 1981;136:807–808U. 178. Mc Dermot t VG, Low VH, Keogan MT , et al. Malignant melanoma met ast at ic t o t he gast roint est inal t rac t . AJR Am J Roent genol. 1996;166:809–813. 179. Mc Donnell CH 3rd, Mc Leod M, Baker ME. Primary perit oneal neuroblast oma: c omput ed t omography f indings. Clin Im aging. 1990;14:41–43. 180. Mendez G, Jr, Isikof f MB, Hill MC. CT of ac ut e panc reat it is: int erim assessment . AJR Am J Roent genol. 1980;135:463–469. 181. Mey ers M. Dy nam ic Radiology of t he Abdom en: Nor m al and Pat hologic Anat om y . 2nd ed. New Y ork: Springer- Verlag; 1982.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2487

16 - Abdominal Wall and Peritoneal Cavity 182. Mey ers MA, Ev ans JA. Ef f ec t s of panc reat it is on t he small bow el and c olon: spread along mesent eric planes. Am J Roent genol Radium T her Nuc l Med. 1973;119:151–165. 183. Mey ers MA, Mc Guire PV. Spiral CT demonst rat ion of hy perv asc ularit y in Crohn disease: “ v asc ular jejunizat ion of t he ileum” or t he “ c omb sign” . Abdom Im aging. 1995;20:327–332. 184. Mey ers MA, Mc Sw eeney J. Sec ondary neoplasms of t he bow el. Radiology 1972;105:1–11. 185. Mey ers MA, Oliphant M, Berne AS, et al. T he perit oneal ligament s and mesent eries: pat hw ay s of int raabdominal spread of disease. Radiology 1987;163:593–604. 186. Mey ers MA. Dist ribut ion of int ra–abdominal malignant seeding:

dependenc y on dy namic s of f low of asc it ic f luid. Am J Roent genol Radium T her Nuc l Med. 1973;119:198–206. 187. Mey ers MA. Roent gen signif ic anc e of t he phrenic oc olic ligament . Radiology 1970;95:539–545. 188. Mey ers MA. T he spread and loc alizat ion of ac ut e int raperit oneal ef f usions. Radiology 1970;95:547–554. 189. Meziane MA, F ishman EK, Siegelman SS. Comput ed t omographic diagnosis of obt urat or f oramen hernia. Gast r oint est Radiol. 1983;8:375–377. 190. Mills SE, Andersen WA, F ec hner RE, et al. Serous surf ac e papillary c arc inoma. A c linic opat hologic st udy of 10 c ases and c omparison w it h st age III–IV ov arian serous c arc inoma. Am J Sur g Pat hol. 1988;12:827–834. 191. Mindelzun RE, Jef f rey RB Jr, Lane MJ, et al. T he mist y mesent ery on CT : dif f erent ial diagnosis. AJR Am J Roent genol. 1996;167:61–65. 192. Mit c hell DG, Hill MC, Hill S, et al. Serous c arc inoma of t he ov ary : CT ident if ic at ion of met ast at ic c alc if ied implant s. Radiology 1986;158:649–652. 193. Molment i EP, Balf e DM, Kant erman RY , et al. Anat omy of t he ret roperit oneum: observ at ions of t he dist ribut ion of pat hologic f luid c ollec t ions. Radiology 1996;200:95–103. 194. Moon KL Jr, F ederle MP, Abrams DI, et al. Kaposi sarc oma and ly mphadenopat hy sy ndrome: limit at ions of abdominal CT in ac quired immunodef ic ienc y sy ndrome. Radiology 1984;150: 479–483. 195. Mueller PR, F erruc c i JT Jr, Harbin WP, et al. Appearanc e of ly mphomat ous inv olv ement of t he mesent ery by ult rasonography and body c omput ed t omography : t he “ sandw ic h sign.” Radiology 1980;134:467–473.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2488

16 - Abdominal Wall and Peritoneal Cavity 196. Mueller PR, F erruc c i JT Jr, Simeone JF , et al. Lesser sac absc esses and f luid c ollec t ions: drainage by t ranshepat ic approac h. Radiology 1985;155:615–618. 197. Mueller PR, F erruc c i JT , Jr, Simeone JF , et al. Det ec t ion and drainage of bilomas: spec ial c onsiderat ions. AJR Am J Roent genol. 1983;140:715–720.

198. Munk PL, Lee MJ, Poon PY , et al. Comput ed t omography of ret roperit oneal and mesent eric sarc omas: a pic t orial essay . Can Assoc Radiol J. 1996;47:335–341. 199. Murakami R, T ajima H, Kobay ashi Y , et al. Mesent eric sc hw annoma. Eur Radiol. 1998;8:277–279. 200. Nanakaw a S, T akahashi M, T akagi K, et al. T he role of c omput ed t omography in management of pat ient s w it h Crohn disease. Clin Im aging. 1993;17:193–198. 201. Nay lor EW, Gardner EJ, Ric hards RC. Desmoid t umors and mesent eric f ibromat osis in Gardner's sy ndrome: report of kindred 109. Ar c h Sur g. 1979;114:1181–1185. 202. Nef f CC, v anSonnenberg E, Casola G, et al. Div ert ic ular absc esses: perc ut aneous drainage. Radiology 1987;163:15–18. 203. New PF , Aronow S. At t enuat ion measurement s of w hole blood and blood f rac t ions in c omput ed t omography . Radiology 1976;121: 635–640. 204. Noone T C, Semelka RC, Woraw at t anakul S, et al. Int raperit oneal absc esses: diagnost ic ac c urac y of and appearanc es at MR imaging. Radiology 1998;208:525–528. 205. Norman D, Pric e D, Boy d D, et al. Quant it at iv e aspec t s of c omput ed t omography of t he blood and c erebrospinal f luid. Radiology 1977;123:335–338. 206. Nov et sky GJ, Berlin L, Epst ein AJ, et al. Case report . Pseudomy xoma perit onei. J Com put Assist T om ogr . 1982;6:398–399. 207. Nunez D, Jr, Huber JS, Y rizarry JM, et al. Nonsurgic al drainage of appendic eal absc esses. AJR Am J Roent genol. 1986;146: 587–589. 208. Ny berg DA, F ederle MP, Jef f rey RB, et al. Abdominal CT f indings of disseminat ed My c obac t erium av ium- int rac ellulare in AIDS. AJR Am J Roent genol. 1985;145:297–299. 209. Ny berg DA, Jef f rey RB Jr, F ederle MP, et al. AIDS- relat ed ly mphomas: ev aluat ion by abdominal CT . Radiology 1986;159: 59–63. 210. O'Neil JD, Ros PR, St orm BL, et al. Cy st ic mesot helioma of t he perit oneum. Radiology 1989;170:333–337.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2489

16 - Abdominal Wall and Peritoneal Cavity 211. Oc hsner A, Grav es A. Subphrenic absc ess: an analy sis of 3372 c ollec t ed and personal c ases. Ann Sur g. 1933;98:961–990. 212. Okino Y , Kiy osue H, Mori H, et al. Root of t he small- bow el mesent ery : c orrelat iv e anat omy and CT f eat ures of pat hologic c ondit ions. Radiogr aphic s 2001;21:1475–1490.

213. Oliphant M, Berne AS, Mey ers MA. Bidirec t ional spread of disease v ia t he subperit oneal spac e: t he low er abdomen and lef t pelv is. Abdom Im aging. 1993;18:117–125. 214. Oliphant M, Berne AS, Mey ers MA. Direc t spread of subperit oneal disease int o solid organs: radiologic diagnosis. Abdom Im aging. 1995;20:141–147; disc ussion 147–148. 215. Oliphant M, Berne AS, Mey ers MA. Imaging t he direc t bidirec t ional spread of disease bet w een t he abdomen and t he f emale pelv is v ia t he subperit oneal spac e. Gast r oint est Radiol. 1988;13: 285–298. 216. Oliphant M, Berne AS, Mey ers MA. Spread of disease v ia t he subperit oneal spac e: t he small bow el mesent ery . Abdom Im aging. 1993;18:109–116. 217. Oliphant M, Berne AS. Comput ed t omography of t he subperit oneal spac e: demonst rat ion of direc t spread of int raabdominal disease. J Com put Assist T om ogr . 1982;6:1127–1237. 218. Ozgen A, Akat a D, Akhan O, et al. Giant benign c y st ic perit oneal mesot helioma: US, CT , and MRI f indings. Abdom Im aging. 1998;23:502–504. 219. Pandolf o I, Blandino A, Gaet a M, et al. CT f indings in palpable lesions of t he ant erior abdominal w all. J Com put Assist T om ogr . 1986;10:629–633. 220. Pant ongrag- Brow n L, Buet ow PC, Carr NJ, et al. Calc if ic at ion and f ibrosis in mesent eric c arc inoid t umor: CT f indings and pat hologic c orrelat ion. AJR Am J Roent genol. 1995;164: 387–391. 221. Past akia B, Horv at h K, Kurt z D, et al. Giant rec t us sheat h hemat omas of t he pelv is c omplic at ing ant ic oagulant t herapy : CT f indings. J Com put Assist T om ogr . 1984;8(6):1120–1123. 222. Pat t en RM, Shuman WP, T eef ey S. Subc ut aneous met ast ases f rom malignant melanoma: prev alenc e and f indings on CT . AJR Am J Roent genol. 1989;152:1009–1012. 223. Pereira JM, Sirlin CB, Pint o PS, et al. CT and MR imaging of ext rahepat ic f at t y masses of t he abdomen and pelv is: t ec hniques, diagnosis, dif f erent ial diagnosis, and pit f alls. Radiogr aphic s 2005;25: 69–85. P.1152

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2490

16 - Abdominal Wall and Peritoneal Cavity 224. Pet ers J, Reinert son J, Polansky , SM, et al. CT demonst rat ion of t raumat ic v ent ral hernia. J Com put Assist T om ogr . 1988;12: 710–711. 225. Pev arski DJ, Mergo PJ, Ros PR. Perit oneal c arc inomat osis due t o

t ransit ional c ell c arc inoma of t he bladder: CT f indings in t w o pat ient s. AJR Am J Roent genol. 1995;164:929–930. 226. Pic khardt PJ, Bhalla S. Unusual nonneoplast ic perit oneal and subperit oneal c ondit ions: CT f indings. Radiogr aphic s 2005;25: 719–730. 227. Pic khardt PJ, F isher AJ, Balf e DM, et al. Desmoplast ic small round c ell t umor of t he abdomen: radiologic - hist opat hologic c orrelat ion. Radiology 1999;210:633–638. 228. Pines B, Rabinov it c h J, Biller SB. Primary t orsion and inf arc t ion of t he appendic es epiploic a. Ar c h Sur g. 1941;42:775–787. 229. Pit t H. Perit onit is, int raabdominal absc ess, and ret roperit oneal absc ess. In: Sur ger y of t he alim ent ar y t r ac t , 2nd ed. Philadelphia: WB Saunders; 1986. 230. Polet t i PA, Plat on A, Rut sc hmann O, et al. Ac ut e lef t c olonic div ert ic ulit is: c an CT f indings be used t o predic t rec urrenc e? AJR Am J Roent genol. 2004;182:1159–1165. 231. Pray son RA, Hart WR, Pet ras RE. Pseudomy xoma perit onei. A c linic opat hologic st udy of 19 c ases w it h emphasis on sit e of origin and nat ure of assoc iat ed ov arian t umors. Am J Sur g Pat hol. 1994;18:591–603. 232. Press OW, Press NO, Kauf man SD. Ev aluat ion and management of c hy lous asc it es. Ann Int er n Med. 1982;96:358–364. 233. Puy laert JB. Right - sided segment al inf arc t ion of t he oment um: c linic al, US, and CT f indings. Radiology 1992;185:169–172. 234. Radin R. HIV inf ec t ion: analy sis in 259 c onsec ut iv e pat ient s w it h abnormal abdominal CT f indings. Radiology 1995;197: 712–722. 235. Raghav endra BN, Griec o AJ, Balt hazar EJ, et al. Diagnost ic ut ilit y of sonography and c omput ed t omography in spont aneous mesent eric hemat oma. Am J Gast r oent er ol. 1982;77:570–573. 236. Ramboer K, Moons P, DeBreuc k Y , et al. Benign mesent eric sc hw annoma: MRI f indings. J Belge Radiol. 1998;81:3–4. 237. Rao PM, Rhea JT , Nov elline RA. CT diagnosis of mesent eric adenit is. Radiology 1997;202:145–149. 238. Rao PM, Wit t enberg J, Law rason JN. Primary epiploic appendagit is: ev olut ionary c hanges in CT appearanc e. Radiology 1997;204:713–717. 239. Rao PM. CT of div ert ic ulit is and alt ernat iv e c ondit ions. Sem in Ult r asound CT MR. 1999;20:86–93.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2491

16 - Abdominal Wall and Peritoneal Cavity

240. Ray CE Jr, Wilbur AC. CT diagnosis of c onc urrent hemat omas of t he psoas musc le and rec t us sheat h: c ase report s and rev iew of anat omy , pat hogenesis, and imaging. Clin Im aging. 1993;17: 22–26. 241. Reddy D, Salomon C, Demos T C, et al. Mesent eric ly mph node c av it at ion in c eliac disease. AJR Am J Roent genol. 2002;178):247. 242. Reut er K, Rapt opoulos V, Reale F , et al. Diagnosis of perit oneal mesot helioma: c omput ed t omography , sonography , and f ine- needle aspirat ion biopsy . AJR Am J Roent genol. 1983;140: 1189–1194. 243. Rha SE, Ha HK, Kim AY , et al. Perit oneal leiomy osarc omat osis originat ing f rom gast roint est inal leiomy osarc omas: CT f eat ures. Radiology 2003;227:385–390. 244. Rha SE, Ha HK, Kim JG, et al. CT f eat ures of int raperit oneal manif est at ions of parasit ic inf est at ion. AJR Am J Roent genol. 1999;172:1289–1292. 245. Rijke AM, F alke T H, de Vries RR. Comput ed t omography in Whipple disease. J Com put Assist T om ogr . 1983;7:1101–1102. 246. Rodrigues A, Whit t en C. Roent genologic c linic al pat hologic c ase. Inv est Radiol. 1993;28:260–262. 247. Rodriguez E, Pombo F . Perit oneal t uberc ulosis v ersus perit oneal c arc inomat osis: dist inc t ion based on CT f indings. J Com put Assist T om ogr . 1996;20:269–272. 248. Ronnet t BM, Kurman RJ, Zahn CM, et al. Pseudomy xoma perit onei in w omen: a c linic opat hologic analy sis of 30 c ases w it h emphasis on sit e of origin, prognosis, and relat ionship t o ov arian muc inous t umors of low malignant pot ent ial. Hum Pat hol. 1995;26:509–524. 249. Ros PR, Olmst ed WW, Moser RP Jr, et al. Mesent eric and oment al c y st s: hist ologic c lassif ic at ion w it h imaging c orrelat ion. Radiology 1987;164:327–332. 250. Rosen A, Korobkin M, Silv erman PM, et al. Mesent eric v ein t hrombosis: CT ident if ic at ion. AJR Am J Roent genol. 1984;143: 83–86. 251. Ross MJ, Welc h WR, Sc ully RE. Mult iloc ular perit oneal inc lusion c y st s (soc alled c y st ic mesot heliomas). Canc er 1989;64: 1336–1346. 252. Rubin JI, Gomori JM, Grossman RI, et al. High- f ield MR imaging of ext rac ranial hemat omas. AJR Am J Roent genol. 1987;148: 813–817. 253. Rust RJ, Kopec ky KK, Holden RW. T he t riangle sign: a CT sign of int raperit oneal f luid. Gast r oint est Radiol. 1984;9:107–113.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2492

16 - Abdominal Wall and Peritoneal Cavity 254. Sabat e JM, T orrubia S, Maideu J, et al. Sc lerosing mesent erit is: imaging f indings in 17 pat ient s. AJR Am J Roent genol. 1999;172: 625–629. 255. Saf rit HD, Mauro MA, Jaques PF . Perc ut aneous absc ess drainage in Crohn's disease. AJR Am J Roent genol. 1987;148:859–862. 256. Sanders RC. T he c hanging epidemiology of subphrenic absc ess and it s c linic al and radiologic al c onsequenc es. Br J Sur g. 1970; 57:449–455. 257. Sandrasegaran K, Lall C, Rajesh A, et al. Dist inguishing gelat in bioabsorbable sponge and post operat iv e abdominal absc ess on CT . AJR Am J Roent genol 2005;184:475–480. 258. Sandrasegaran K, Maglint e DD, Rajesh A, et al. Primary epiploic appendagit is: CT diagnosis. Em er g Radiol. 2004;11:9–14. 259. Sc hec ht er S, Eisenst at T E, Oliv er GC, et al. Comput erized t omographic sc an- guided drainage of int ra- abdominal absc esses. Preoperat iv e and post operat iv e modalit ies in c olon and rec t al surgery . Dis Colon Rec t um . 1994;37:984–988. 260. Sc hneeklot h G, T errier F , F uc hs WA. Comput ed t omography of int raperit oneal absc esses. Gast r oint est Radiol. 1982;7:35–41. 261. Semelka RC, John G, Kelekis NL, et al. Bow el- relat ed absc esses: MR demonst rat ion preliminary result s. Magn Reson Im aging. 1998;16(8):855–861. 262. Semelka RC, Law renc e PH, Shoenut JP, et al. Primary ov arian c anc er: prospec t iv e c omparison of c ont rast - enhanc ed CT and pre- and post c ont rast ,

f at - suppressed MR imaging, w it h hist ologic c orrelat ion. J Magn Reson Im aging. 1993;3(1):99–106. 263. Seshul MB, Coulam CM. Pseudomy xoma perit onei: c omput ed t omography and sonography . AJR Am J Roent genol. 1981;136: 803–806. 264. Shac kelf ord GD, Mc Alist er WH. Cy st s of t he oment um. Pediat r Radiol. 1975;3:152–155. 265. Shac kelf ord R, Grose W. Groin hernia. 5 In: Shac kelf ord RT , Zuidema GD, eds Sur ger y of t he alim ent ar y t r ac t , 2 nd ed Philadelphia: WB Saunders, 1986. 266. Sharif HS, Clark DC, Aabed MY , et al. MR imaging of t horac ic and abdominal w all inf ec t ions: c omparison w it h ot her imaging proc edures. AJR Am J Roent genol. 1990;154(5):989–995. 267. Sherman NJ, Dav is JR, Jesseph JE. Subphrenic absc ess. A c ont inuing hazard. Am J Sur g. 1969;117:117–123.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2493

16 - Abdominal Wall and Peritoneal Cavity 268. Shet h S, Hort on KM, Garland MR, et al. Mesent eric neoplasms: CT appearanc es of primary and sec ondary t umors and dif f erent ial diagnosis. Radiogr aphic s 2003;23:457–473; quiz 535–536. 269. Shew ard SE, Williams AG Jr, Met t ler F A Jr, et al. CT appearanc e of a surgic ally ret ained t ow el (gossy piboma). J Com put Assist T om ogr . 1986;10:343–345.

270. Shin MS, F erruc c i JT Jr, Wit t enberg J. Comput ed t omographic diagnosis of pseudoasc it es (f loat ing v isc era sy ndrome). J Com put Assist T om ogr . 1978;2:594–597. 271. Siew ert B, Rapt opoulos V. CT of t he ac ut e abdomen: f indings and impac t on diagnosis and t reat ment . AJR Am J Roent genol. 1994;163:1317–1324. 272. Silv erman PM, Baker ME, Cooper C, et al. CT appearanc e of dif f use mesent eric edema. J Com put Assist T om ogr . 1986;10:67–70. 273. Silv erman PM, Kelv in F M, Korobkin M, et al. Comput ed t omography of t he normal mesent ery . AJR Am J Roent genol. 1984;143: 953–957. 274. Silv erst ein W, Isikof f MB, Hill MC, et al. Diagnost ic imaging of ac ut e panc reat it is: prospec t iv e st udy using CT and sonography . AJR Am J Roent genol. 1981;137:497–502. 275. Singh AK, Gerv ais DA, Hahn PF , et al. CT appearanc e of ac ut e appendagit is. AJR Am J Roent genol. 2004;183:1303–1307. 276. Sirv anc i M, Balc i NC, Karaman K, Duran C, et al. Primary epiploic appendagit is: MRI f indings. Magn Reson Im aging. 2002;20: 137–139. 277. Siv it CJ, Pec let MH, T ay lor GA. Lif e- t hreat ening int raperit oneal bleeding: demonst rat ion w it h CT . Radiology 1989;171:430. P.1153 278. Sompay rac SW, Mindelzun RE, Silv erman PM, et al. T he great er oment um. AJR Am J Roent genol. 1997;168:683–687. 279. Sones PJ. Perc ut aneous drainage of abdominal absc esses. AJR Am J Roent genol. 1984;142:35–39. 280. Srinualnad N, Dixon AK. Right ant erior subphrenic spac e: an import ant sit e f or t he early det ec t ion of int raperit oneal f luid on abdominal CT . Abdom Im aging. 1999;24:614–617. 281. St af f ord- Johnson DB, Bree RL, F ranc is IR, et al. CT appearanc e of primary papillary serous c arc inoma of t he perit oneum. AJR Am J Roent genol. 1998;171:687–689.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2494

16 - Abdominal Wall and Peritoneal Cavity 282. St af f ord- Johnson DB, Wilson T E, F ranc is IR, et al. CT appearanc e of sc lerosing perit onit is in pat ient s on c hronic ambulat ory perit oneal dialy sis. J Com put Assist T om ogr . 1998;22:295–299. 283. St ec k WD, Helw ig EB. Cut aneous endomet riosis. Clin Obst et Gy nec ol. 1966;9:373–383. 284. St ef ansson T , Ny man R, Nilsson S, et al. Div ert ic ulit is of t he sigmoid c olon. A c omparison of CT , c olonic enema and laparosc opy . Ac t a Radiol. 1997;38:313–319.

285. St oupis C, Ros PR, Abbit t PL, et al. Bubbles in t he belly : imaging of c y st ic mesent eric or oment al masses. Radiogr aphic s 1994;14: 729–737. 286. Sugarbaker PH, Ac herman Y I, Gonzalez- Moreno S, et al. Diagnosis and t reat ment of perit oneal mesot helioma: T he Washingt on Canc er Inst it ut e experienc e. Sem in Onc ol. 2002;29:51–61. 287. Sulkin T V, O'Neill H, Amin AI, et al. CT in pseudomy xoma perit onei: a rev iew of 17 c ases. Clin Radiol. 2002;57:608–613. 288. Sw ensen SJ, Mc Leod RA, St ephens DH. CT of ext rac ranial hemorrhage and hemat omas. AJR Am J Roent genol. 1984;143: 907–912. 289. T aneja K, Got hi R, Kumar K, et al. Perit oneal Ec hinoc oc c us mult iloc ularis inf ec t ion: CT appearanc e. J Com put Assist T om ogr . 1990;14:493–494. 290. T aourel P, Pradel J, F abre JM, et al. Role of CT in t he ac ut e nont raumat ic abdomen. Sem in Ult r asound CT MR. 1995;16: 151–164. 291. T art ar VM, Heiken JP, Mc Clennan BL. Renal c ell c arc inoma present ing w it h dif f use perit oneal met ast ases: CT f indings. J Com put Assist T om ogr . 1991;15:450–453. 292. T at eishi U, Hasegaw a T , Kusumot o M, et al. Desmoplast ic small round c ell t umor: imaging f indings assoc iat ed w it h c linic opat hologic f eat ures. J Com put Assist T om ogr . 2002;26:579–583. 293. T empany CM, Zou KH, Silv erman SG, et al. St aging of adv anc ed ov arian c anc er: c omparison of imaging modalit ies—report f rom t he Radiologic al Diagnost ic Onc ology Group. Radiology 2000;215: 761–777. 294. T errier F , Rev el D, Pajannen H, et al. MR imaging of body f luid c ollec t ions. J Com put Assist T om ogr . 1986;10:953–962. 295. T hoeni RF , Margulis AR. Gast roint est inal t uberc ulosis. Sem in Roent genol. 1979;14:283–294. 296. T y rrel RT , Mont emay or KA, Bernardino ME. CT densit y of mesent eric , ret roperit oneal, and subc ut aneous f at in c irrhot ic pat ient s: c omparison w it h c ont rol subjec t s. AJR Am J Roent genol. 1990;155:73–75.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2495

16 - Abdominal Wall and Peritoneal Cavity 297. Unger EC, Glazer HS, Lee JK, et al. MRI of ext rac ranial hemat omas: preliminary observ at ions. AJR Am J Roent genol. 1986;146: 403–407. 298. v an Breda Vriesman AC, de Mol v an Ot t erloo AJ, et al. Epiploic appendagit is and oment al inf arc t ion. Eur J Sur g. 2001;167: 723–727.

299. v an Breda Vriesman AC, Lohle PN, Coerkamp EG, Puy laert JB. Inf arc t ion of oment um and epiploic appendage: diagnosis, epidemiology and nat ural hist ory . Eur Radiol. 1999;9:1886–1892. 300. v an Breda Vriesman AC, Sc hut t ev aer HM, Coerkamp EG, et al. Mesent eric pannic ulit is: US and CT f eat ures. Eur Radiol. 2004;14: 2242–2248. 301. Vanek VW, Phillips AK. Ret roperit oneal, mesent eric , and oment al c y st s. Ar c h Sur g. 1984;119:838–482. 302. v anSonnenberg E, D'Agost ino HB, Casola G, et al. Perc ut aneous absc ess drainage: c urrent c onc ept s. Radiology 1991;181: 617–626. 303. v anSonnenberg E, Mueller PR, F erruc c i JT Jr. Perc ut aneous drainage of 250 abdominal absc esses and f luid c ollec t ions. Part I: Result s, f ailures, and c omplic at ions. Radiology 1984;151: 337–341. 304. v anSonnenberg E, Wit t ic h GR, Casola G, et al. Periappendic eal absc esses: perc ut aneous drainage. Radiology 1987;163:23–26. 305. Vazquez JL, T horsen MK, Dodds WJ, et al. Ev aluat ion and t reat ment of int raabdominal bilomas. AJR Am J Roent genol. 1985;144: 933–938. 306. Viala J, Moric e P, Paut ier P, et al. CT f indings in t w o c ases of port - sit e met ast asis af t er laparosc opy f or ov arian c anc er. Eur J Gy nec Onc ol. 2002;4:293–294. 307. Vinc ent LM, Mauro MA, Mit t elst aedt CA. T he lesser sac and gast rohepat ic rec ess: sonographic appearanc e and dif f erent iat ion of f luid c ollec t ions. Radiology 1984;150:515–519. 308. Walensky RP, Venbrux AC, Presc ot t CA, et al. Pseudomy xoma perit onei. AJR Am J Roent genol. 1996;167:471–474. 309. Wall SD, Hric ak H, Bailey GD, et al. MR imaging of pat hologic abdominal f luid c ollec t ions. J Comput Assist T omogr 1986;10:746–750. 310. Wang SM, Wilson SE. Subphrenic absc ess. T he new epidemiology . Ar c h Sur g. 1977;112(8):934–936. 311. Weiss SW, T av assoli F A. Mult ic y st ic mesot helioma. An analy sis of pat hologic f indings and biologic behav ior in 37 c ases. Am J Sur g Pat hol. 1988;12:737–746. 312. Whang SH, Lee KS, Kim PN, et al. Oment al t erat oma in an adult : a c ase report . Gast r oint est Radiol. 1990;15:301–302.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2496

16 - Abdominal Wall and Peritoneal Cavity 313. Whit e M, Mueller PR, F erruc c i JT Jr, et al. Perc ut aneous drainage of post operat iv e abdominal and pelv ic ly mphoc eles. AJR Am J Roent genol. 1985;145:1065–1069.

314. Whit ley N. Mesent eric disease. In: Mey ers MA, ed. Com put ed t om ogr aphy of t he gast r oint est inal t r ac t . New Y ork: Springer- Verlag. 1986. 315. Whit ley NO, Bohlman ME, Baker LP. CT pat t erns of mesent eric disease. J Com put Assist T om ogr . 1982;6:490–496. 316. Whit ley NO, Brenner DE, Ant man KH, et al. CT of perit oneal mesot helioma: analy sis of eight c ases. AJR Am J Roent genol. 1982;138:531–535. 317. Wolf GC, Kopec ky KK. MR imaging of endomet riosis arising in c esarean sec t ion sc ar. J Com put Assist T om ogr . 1989;13: 150–152. 318. Wolv erson MK, Crepps LF , Sundaram M, et al. Hy perdensit y of rec ent hemorrhage at body c omput ed t omography : inc idenc e and morphologic v ariat ion. Radiology 1983;148:779–784. 319. Wolv erson MK, Jagannadharao B, Sundaram M, et al. CT as a primary diagnost ic met hod in ev aluat ing int raabdominal absc ess. AJR Am J Roent genol. 1979;133:1089–1095. 320. Wong WL, Johns T A, Herlihy WG, et al. Best c ases f rom t he AF IP: mult ic y st ic mesot helioma. Radiogr aphic s 2004;24:247–250. 321. Woodard PK, F eldman JM, Paine SS, et al. Midgut c arc inoid t umors: CT f indings and bioc hemic al prof iles. J Com put Assist T om ogr . 1995;19:400–405. 322. Woodw ard PJ, Hosseinzadeh K, Saenger JS. F rom t he arc hiv es of t he AF IP: radiologic st aging of ov arian c arc inoma w it h pat hologic c orrelat ion. Radiogr aphic s 2004;24:225–246. 323. Y eh HC, Rabinow it z JG. Ult rasonography and c omput ed t omography of inf lammat ory abdominal w all lesions. Radiology 1982;144: 859–863. 324. Y eh HC, Shaf ir MK, Slat er G, et al. Ult rasonography and c omput ed t omography in pseudomy xoma perit onei. Radiology 1984; 153:507–510. 325. Y eh HC. Ult rasonography of perit oneal t umors. Radiology 1979; 133(2):419–24. 326. Y oung RH, Gilks CB, Sc ully RE. Muc inous t umors of t he appendix assoc iat ed w it h muc inous t umors of t he ov ary and pseudomy xoma perit onei. A c linic opat hologic al analy sis of 22 c ases support ing an origin in t he appendix. Am J Sur g Pat hol. 1991;15:415–429.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2497

16 - Abdominal Wall and Peritoneal Cavity 327. Y oung ST , Paulson EK, Mc Cann RL, Baker ME. Appearanc e of oxidized c ellulose (Surgic el) on post operat iv e CT sc ans: similarit y t o post operat iv e absc ess. AJR Am J Roent genol. 1993;160: 275–277. 328. Zarv an NP, Lee F T Jr, Y andow DR, et al. Abdominal hernias: CT f indings. AJR Am J Roent genol. 1995;164:1391–1395. 329. Zerhouni EA, Bart h KH, Siegelman SS. Demonst rat ion of v enous t hrombosis by c omput ed t omography . AJR Am J Roent genol. 1980;134:753–758. 330. Zissin R, Hert z M, Shapiro–F einberg M, et al. Primary serous papillary c arc inoma of t he perit oneum: CT f indings. Clin Radiol. 2001;56:740–745.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

Thi s pa ge i s i ntenti ona l l y l eft bl a nk. Remove thi s text from the ma nua l templ a te i f you wa nt i t compl etel y bl a nk.

17 - Retroperitoneum

2500

17 - Retroperitoneum 22

17 - Retroperitoneum Editors: Le e , Jose ph K. T. ; Sa ge l, Stua rt S. ; Sta nle y , Robe rt J. ; He ike n, Ja y P. Title : C ompute d Body Tomogra phy with MRI C orre la tion , 4th Edition Copy right В©2006 Lippinc ot t Williams & Wilkins > T able of Cont ent s > 17 - Ret roperit oneum

17 Retroperitoneum Da v id M. Wa rsha ue r Jose ph K. T. Le e Ha rish Pa te l T he ret roperit oneum is bounded ant eriorly by t he pariet al perit oneum and medially , post eriorly , and lat erally by f asc ia c ov ering t he psoas, quadrat us lumborum, and t ransv ersus abdominus musc ulat ure, respec t iv ely . It ext ends f rom t he diaphragm superiorly t o t he lev el of t he pelv ic v isc era inf eriorly . At t he lev el of t he kidney s, t he ret roperit oneal spac e is div ided int o t hree disc reet c ompart ment s—t he perirenal spac e surrounded by t he ant erior and post erior pararenal spac es (F igs. 17- 1 and 17- 2) (25,164,209). T he perirenal spac e surrounds t he kidney and adrenal and is bounded ant eriorly by t he ant erior renal f asc ia (Gerot a's) and post eriorly by t he post erior renal f asc ia (Zuc kerkandl's). T he perirenal spac es c an c ommunic at e ac ross t he midline, alt hough t his is inc onst ant , suggest ing a part ial or f enest rat ed barrier in t he region ant erior t o t he aort a and inf erior v ena c av a (IVC) (265,317). T he perirenal spac es also may inf requent ly c ommunic at e inf eriorly w it h t he inf rarenal spac e and pelv ic ext raperit oneal spac es and superiorly w it h t he diaphragmat ic surf ac e and bare area of t he liv er (189,211). T he ant erior pararenal spac e c ont ains t he asc ending and desc ending c olon as w ell as t he duodenum and panc reas. It is bordered ant eriorly by t he post erior perit oneum, post eriorly by t he ant erior renal f asc ia, and lat erally by t he lat eral c onal f asc ia represent ing t he f usion of t he ant erior and post erior renal f asc ia. T he post erior pararenal spac e c ont ains only f at . Bot h t he ant erior and post erior pararenal spac es c ommunic at e inf eriorly w it h t he inf rarenal spac e and ext raperit oneal pelv ic spac e and c ommunic at e superiorly w it h t he ext raperit oneal subdiaphragmat ic spac e.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2501

17 - Retroperitoneum

Addit ional pot ent ial ret roperit oneal spac es exist w it hin t he f asc ial planes t hat separat e t he perirenal and pararenal spac es. T hese f asc ia, originally f ormed by f usion of t w o embry ologic f asc ial planes, may be split by and c ont ain pat hologic f luid c ollec t ions. A pot ent ial ret romesent eric (or ant erior int erf asc ial) spac e exist s w it hin t he ant erior renal f asc ia, w it h a similar pot ent ial ret rorenal (or post erior int erf asc ial) spac e exist ing in t he post erior renal f asc ia and a lat eroc onal spac e oc c urring in t he lat eroc onal f asc ia. T hese pot ent ial f asc ial spac es also allow t he ext ension of f luid c ollec t ions f rom t he ret roperit oneum t o t he ext raperit oneal pelv is (216). T w o t y pes of v isc era exist in t he ret roperit oneal spac e: t he t rue embry onic ret roperit oneal organs (i.e., t he adrenal glands, kidney s, uret ers, and gonads) and t hose st ruc t ures c losely at t ac hed t o t he post erior abdominal w all and only part ly c ov ered by t he perit oneum and f asc ia (i.e., aort a, IVC, panc reas, port ions of t he duodenum, c olon, ly mph nodes, and nerv es). In t his c hapt er, disc ussion is limit ed t o diseases inv olv ing t he great v essels, ly mph nodes, and psoas musc ulat ure, as w ell as primary ret roperit oneal neoplasms. Diseases relat ed t o ot her solid ret roperit oneal organs, suc h as t he kidney s, t he adrenals, and t he panc reas, are c ov ered in ot her c hapt ers. T he diagnosis of ret roperit oneal pat hology has hist oric ally present ed a c hallenge t o phy sic ians. T he signs and sy mpt oms of ret roperit oneal diseases are my riad and of t en subt le. Bec ause c omput ed t omography (CT ) and magnet ic resonanc e imaging (MRI) allow direc t , noninv asiv e demonst rat ion of normal and pat hologic ret roperit oneal anat omy w it h a high lev el of c larit y , bot h met hods are now used rout inely f or ev aluat ing ret roperit oneal diseases. Wit h c urrent t ec hnology , diagnost ic images c an be obt ained ev en in v ery emac iat ed and c rit ic ally ill pat ient s (F ig. 17- 3).

TECHNIQUE Computed Tomography As in ot her part s of t he body , c aref ul pat ient preparat ion and at t ent ion t o t ec hnic al det ails are essent ial t o t he opt imal c onduc t of CT ev aluat ion of t he ret roperit oneum. T he exac t P.1156 st udy prot oc ol v aries depending on t he t y pe of sc anner av ailable, t he indic at ion(s) of t he examinat ion, and t he area t o be imaged. F or a surv ey

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2502

17 - Retroperitoneum examinat ion of t he ret roperit oneum 5- t o 7- mm- t hic k slic es are obt ained if a single det ec t or row helic al CT sc anner is used. If a 4- t o 16- slic e mult idet ec t or row CT (MDCT ) sc anner is used, a 5- mm- t hic k slic e is rout ine using 1- t o 2- mm det ec t or c ollimat ion. F or angiographic ev aluat ion of t he aort a and it s major branc hes, t hinner c ollimat ion (0.5 t o 0.7 mm) is rout inely

used on t he MDCT sc anner (F ig. 17- 4). Images may be rec onst ruc t ed at 1- t o 2- mm int erv als in any def ined plane; t hese images c an be print ed eit her on hard c opy f ilms or sent t o a pic t ure arc hiv ing and c ommunic at ion sy st em (PACS) v iew ing st at ion f or int erpret at ion. Alt ernat iv ely , t he ent ire dat a set may be v iew ed int erac t iv ely on a dedic at ed c omput er w orkst at ion.

F igure 17- 1 Ret roperit oneal spac es (axial image). T he ant erior pararenal spac e (light gr ey ) is bounded ant eriorly by t he perit oneum and post eriorly by t he ant erior renal f asc ia and c ont ains t he asc ending (AC) and desc ending (DC) c olon, duodenum (D), and panc reas (P). T he perirenal spac e (dot t ed) is bordered by t he ant erior and post erior perirenal f asc ia and c ont ains t he lef t (LK) and right (RK) kidney s and great v essels: IVC, inf erior v ena c av a; A, aort a. T he post erior pararenal spac e (dar k gr ey ) is bordered ant eriorly by t he post erior perirenal f asc ia, lat eral c onal f asc ia, and perit oneum (f rom medial t o lat eral) and post eriorly by t he t ransv ersalis f asc ia.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2503

17 - Retroperitoneum

F igure 17- 2 Ret roperit oneal spac es (sagit t al image): Ant erior pararenal spac e (light gr ey ), perirenal spac e (dot t ed), and post erior pararenal spac e (dar k gr ey ). Alt hough c losed at t heir superior ends, t he ret roperit oneal spac es may c ommunic at e inf eriorly w it h t he pelv ic ext raperit oneal spac e. L, liv er; AD, adrenal; K, kidney ; D, duodenum; C, c olon.

Exc ept in emergenc y sit uat ions in w hic h t he CT examinat ion must be perf ormed w it hout delay (e.g., in pat ient s w it h suspec t ed rupt ured abdominal aort ic aneury sms), ret roperit oneal CT should be done only af t er t he pat ient has ingest ed oral c ont rast media. Approximat ely 1,000 mL of oral c ont rast mat erial (dilut e barium suspension or iodinat ed w at er- soluble c ont rast mat erial) is giv en t o t he pat ient at least 1 hour bef ore t he examinat ion t o opac if y t he c olon and dist al small bow el loops. An addit ional 300 t o 500 mL of c ont rast is giv en approximat ely 15 minut es bef ore t he st udy t o opac if y t he st omac h and proximal small bow el loops. If t he pelv is is t o be inc luded, a c ont rast mat erial enema (200 mL) oc c asionally may be nec essary t o expedit e opac if ic at ion of t he rec t osigmoid and desc ending c olon. Alt hough t he ret roperit oneum c an be adequat ely st udied w it hout t he use of int rav enous c ont rast mat erial, most ret roperit oneal CT st udies are perf ormed

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2504

17 - Retroperitoneum w it h int rav enous c ont rast mat erial t o allow dist inc t ion bet w een v asc ular and

nonv asc ular st ruc t ures, t o det ermine t he v asc ularit y of a ret roperit oneal mass and it s ef f ec t on t he urinary t rac t and t o maximize det ec t ion of f oc al lesions in solid abdominal organs. A dose of 150 mL of 60% iodine solut ion is administ ered int rav enously on examinat ions perf ormed on single- slic e helic al CT sc anners; a reduc ed amount (80 t o 120 mL) f ollow ed by 30 mL of saline c an produc e near equiv alent opac if ic at ion w it h MDCT (290). Int rav enous c ont rast mat erial is administ ered v ia a pow er injec t or as a bolus at a rat e of 2 t o 3 mL per sec ond f or rout ine surv ey examinat ions and 3 t o 5 mL per sec ond f or CT angiography . Images are obt ained 25 sec onds af t er t he init iat ion of c ont rast deliv ery f or CT angiography ; a longer delay (60 t o 70 sec onds) is used f or all ot her ret roperit oneal st udies. Alt hough t hese f ixed sc an delay s w ork w ell f or most pat ient s, a dif f erent sc an delay is required in pat ient s w it h alt ered c irc ulat ion t ime (e.g., pat ient s w it h dec reased lef t v ent ric ular f unc t ion). Comput er sof t w are programs are av ailable t o assure more c onsist ent v essel opac if ic at ion by t riggering sc anning only af t er a selec t ed area (e.g., proximal desc ending aort a) reac hes a predet ermined at t enuat ion v alue.

Magnetic Resonance Imaging T he ret roperit oneum c an likew ise be suc c essf ully examined w it h MRI. T ransv erse images are obt ained in all pat ient s, usually w it h 8- t o 10- mm c ollimat ion at 10- t o 12- mm P.1157 int erv als. In addit ion, c oronal and sagit t al images of t en are perf ormed t o bet t er def ine abnormalit ies of t he aort a, IVC, and psoas musc le. T he use of a 2- mm int erslic e gap reduc es “ c rosst alk” bet w een c onsec ut iv e sec t ions.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2505

17 - Retroperitoneum

F igure 17- 3 Comput ed t omography images of t he normal ret roperit oneum in pat ient s w it h v ariat ions in body habit us. A: T hin pat ient w it h lit t le body f at . B: Relat iv e pauc it y of ret roperit oneal and mesent eric f at c ompared w it h subc ut aneous f at , a pat t ern c ommon in w omen. C : Relat iv e prominenc e of ret roperit oneal and mesent eric f at c ompared w it h subc ut aneous f at , a pat t ern c ommon in men. Not e ant erior pararenal f asc ia (ar r ow heads), post erior pararenal f asc ia (ar r ow s). A, aort a; I, inf erior v ena c av a; K, kidney ; ar r ow , lef t renal v ein.

Bot h T 1- and T 2- w eight ed sequenc es are required f or lesion det ec t ion and c harac t erizat ion. T 1- w eight ed imaging c an be ac hiev ed w it h eit her a breat hhold gradient ec ho (GRE) sequenc e [e.g., f ast low - angle shot (F LASH) or spoiled gradient rec alled ac quisit ion in st eady st at e (GRASS)] or a c onv ent ional spin- ec ho (SE) sequenc e [repet it ion t ime (T R) 300 t o 1,000 msec , ec ho t ime (T E) as short as possible]. Alt hough an SE sequenc e is less af f ec t ed by magnet ic susc ept ibilit y art if ac t , w e pref er GRE f or t he T 1w eight ed sequenc e bec ause it allow s mult iple sec t ions t o be obt ained w it hin a single breat h- hold, result ing in high- qualit y images w it hout respirat ory - relat ed art if ac t s and w it h minimal art if ac t s f rom bow el perist alsis. At 1.5 T esla (T ), w it h a T R of 130 msec , T E of 4 msec , f lip angle of 80 degrees, and one exc it at ion, a t ot al of 14 sec t ions c an be obt ained in 19 sec onds. T he short

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2506

17 - Retroperitoneum ac quisit ion t ime of a GRE sequenc e also allow s serial dy namic imaging af t er int rav enous administ rat ion of a gadolinium c ont rast agent . T 2- w eight ed imaging (T R great er t han 1,500 msec , T E great er t han 70 msec ) c an be ac hiev ed w it h a c onv ent ional SE or a rapid SE (e.g., f ast spin ec ho or t urbo spin ec ho) t ec hnique. T he adv ant age of rapid SE ov er c onv ent ional SE sequenc es is a subst ant ial reduc t ion in dat a ac quisit ion t ime. T he reduc ed ac quisit ion t ime c an be used t o improv e spat ial resolut ion (by inc reasing imaging mat rix element s) or obt ain st ronger T 2 w eight ing (by inc reasing T R and obt aining lat er ec hoes) w it hout signif ic ant ly prolonging t he t ot al imaging t ime. Single- shot ec ho- t rain SE sequenc e [e.g., half F ourier snap shot t urbo spin ec ho (HAST E) or single shot f ast spin ec ho (SSF SE)] is a breat hingindependent T 2- w eight ed sequenc e t hat allow s ac quisit ion of high- qualit y

abdominal T 2- w eight ed images ev en in c rit ic ally ill pat ient s. Alt hough rapid SE prov ides bet t er image qualit y and c ont rast - t o- noise rat io (CNR) f or c y st ic abdominal lesions t han does c onv ent ional SE, t he qualit at iv e c onspic uousness and CNR of solid abdominal lesions are dec reased (46). Bot h T 1- and T 2w eight ed sequenc es c an be c ombined w it h f at suppression. F at sat urat ion reduc es ghost ing art if ac t s and inc reases t he c ont rast range of nonf at t y t issues.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2507

17 - Retroperitoneum

F igure 17- 4 Mult idet ec t or row c omput ed t omography . A: Coronal image of t he abdomen show s aort a (A), w it h lef t renal v ein (ar r ow ). B: Coronal image post erior t o (A) show s lef t renal art ery (ar r ow ), w it h right renal v ein (ar r ow head) running int o t he inf erior v ena c av a. C: Sagit t al image show s origin of c eliac axis (ar r ow ) and superior mesent eric art ery (ar r ow head). A, aort a; L, liv er.

P.1158 As in t he c ase of CT , an MR oral c ont rast agent c an aid in t he dif f erent iat ion of bow el f rom ot her normal or pat hologic t issue. A v ariet y of posit iv e and negat iv e gast roint est inal c ont rast agent s, suc h as barium, perf luorooc t y lbromide, iron c ompound, and w at er, hav e been proposed t o opac if y t he gast roint est inal t rac t . How ev er, none of t hem has rec eiv ed

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2508

17 - Retroperitoneum w idespread ac c ept anc e bec ause of t he high c ost of t he c ont rast mat erials, inc onsist enc y in dist ending t he bow el loops, and inc reased susc ept ibilit y art if ac t on t he c ommonly used GRE sequenc es. Int rav enous gadolinium c helat e–based c ont rast is rout inely used in MRI f or ev aluat ion of t he ret roperit oneum. It is giv en by bolus injec t ion at 2 mL per sec ond. T 1w eight ed F LASH images are t hen obt ained immediat ely and 45 sec onds af t er injec t ion. An addit ional F LASH sequenc e at 90 sec onds af t er t he injec t ion is done w it h f at sat urat ion t o c omplet e t he ev aluat ion. T o assess t he v asc ular sy st em, v arious MR angiographic (MRA) met hods hav e been employ ed. Dat a c an be ac quired using a GRE sequenc e or it s v ariant (e.g., t urbo GRE) based on eit her a t ime- of - f light (T OF ) or phase- c ont rast

(PC) t ec hnique (142,154). Alt hough t he t w o- dimensional (2D) T OF t ec hnique is relat iv ely ac c urat e and requires less t ime, in- plane f low sat urat ion of t ort uous v essels and v essels w it h slow f low of t en lead t o subopt imal images. Alt hough t he PC met hod is more sensit iv e t o slow f low , it is more t ime c onsuming and is signif ic ant ly af f ec t ed by signal loss in areas of loc al t urbulenc e (142). T hreedimensional (3D) gadolinium- enhanc ed GRE MRA t ec hnique does not rely on T OF ef f ec t s but rat her on t he T 1 short ening prov ided by P.1159 gadolinium. T his t ec hnique ov erc omes t he disadv ant ages assoc iat ed w it h 2D T OF and PC t ec hniques and is our pref erred t ec hnique. MR angiograms obt ained using 3D gadolinium- enhanc ed GRE and rec onst ruc t ed w it h maximum int ensit y projec t ion (MIP) rendering t ec hnique allow exquisit e display of t he ent ire ret roperit oneal art erial and/or v enous sy st em in mult iple projec t ions (97,107,254) (F ig. 17- 5). F or MRA, 0.1 t o 0.2 mmol/kg body w eight of gadolinium is administ ered int o an ant ic ubit al v ein using a pow er injec t or at a rat e of 2 t o 3 mL per sec ond, f ollow ed by 15 mL of saline t o c lear lines and v eins. A slow er inf usion t ec hnique may be used w hen v isualizat ion of low er ext remit y v essels is required. As in t he c ase of CT , c omput er sof t w are programs exist t hat t rigger t he imaging sequenc e w hen t he int raluminal aort a signal int ensit y reac hes a preselec t ed lev el.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2509

17 - Retroperitoneum

F igure 17- 5 Magnet ic resonanc e angiography . A: T hin- sec t ion gadoliniumenhanc ed T 1- w eight ed c oronal image t hat , w hen t aken w it h adjoining slic es and rec onst ruc t ed as maximum- int ensit y projec t ion (MIP), y ields t hreedimensional v iew s, t w o of w hic h are show n here. B: Coronal MIP. Not e duplic at ed renal art eries bilat erally . C : Sagit t al MIP. A, aort a; ar r ow , renal art eries.

AORTA Normal Anatomy T he abdominal aort a begins at t he hiat us of t he diaphragm and usually ext ends along t he v ent ral aspec t of t he lumbar spine t o t he lev el of t he f ourt h lumbar v ert ebra, w here it div ides int o t he t w o c ommon iliac art eries. T he c aliber of t he abdominal aort a dec reases as it progresses dist ally t ow ard t he bif urc at ion. Men usually hav e larger diamet er v essels t han age- mat c hed w omen, and aort ic diamet er gradually inc reases w it h age in bot h sexes (126). CT measurement s of t he normal aort ic diamet er at t he lev el of t he renal hila v ary f rom a mean of 1.53 c m in w omen in t heir f ourt h dec ade t o 2.10 c m in men in t heir eight h dec ade. Normal inf rarenal aort ic dimensions (just proximal t o t he bif urc at ion) are smaller, av eraging 1.43 c m and 1.96 c m, respec t iv ely , in t hese t w o groups of pat ient s. An aort ic diamet er less t han 12 mm at t he lev el of t he renal art eries should raise t he possibilit y of hy pov olemic shoc k (F ig. 17- 6) (293). T he major branc hes arising f rom t he abdominal aort a—t he c eliac t runk, t he superior mesent ery art ery , renal art eries, and t he inf erior mesent eric

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2510

17 - Retroperitoneum art ery —are w ell apprec iat ed on bot h CT and MRI (355). Small ac c essory renal art eries likew ise c an be demonst rat ed on CT and MR angiograms w hen dat a are ac quired w it h t hin c ollimat ion (107,249).

T he nonc alc if ied aort ic w all c annot be dist inguished f rom int raluminal blood on nonc ont rast CT sc ans exc ept in anemic pat ient s. Whereas t he at t enuat ion v alue of t he blood in t he aort ic lumen ranges f rom 50 t o 70 Hounsf eld unit s (HU) in normal subjec t s, it is c onsiderably less in pat ient s w it h a markedly reduc ed hemat oc rit . T hus, a v isible, nonc alc if ied aort ic w all is a c lue t o t he presenc e of anemia. Af t er bolus int rav enous administ rat ion of w at er- soluble iodinat ed c ont rast medium, t he at t enuat ion v alue of t he aort ic lumen c an rise t o as high as +400 HU. F low ing blood has an appearanc e on MR images t hat is dist inc t f rom t hat of st at ionary t issue. Depending upon t he imaging t ec hnique used, blood may be bright or dark. In general, blood f low ing at normal v eloc it ies (great er t han 10 c m per sec ond) usually produc es no signal on SE sequenc es (espec ially at long T Es) and bright signal on GRE sequenc es (espec ially at short T Es) due t o T OF phenomenon. T heref ore, t he aort a and it s major branc hes appear as areas of signal v oid on SE images, but as bright f oc i on GRE images. Wit h eit her t ec hnique, t hese art eries c an be dist inguished easily f rom t he surrounding ret roperit oneal P.1160 st ruc t ures. How ev er, t he t hin w all of t he normal aort a usually is not c learly ident if ied as a separat e st ruc t ure on eit her SE or GRE images. When t ransaxial images are obt ained w it h a mult islic e SE t ec hnique, t he aort a of t en demonst rat es signal in t he most c ranial slic e of t he imaged v olume bec ause of a f low - relat ed enhanc ement ef f ec t . Plac ement of a presat urat ion band abov e t he imaging v olume eliminat es t his ef f ec t and ensures t hat f low ing blood remains blac k (68).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2511

17 - Retroperitoneum F igure 17- 6 Small aort a in a 17- y ear- old w oman in shoc k af t er a mot or v ehic le ac c ident . A: Cont rast - enhanc ed c omput ed t omography sc an show s a

7- mm diamet er aort a (long blac k ar r ow ) assoc iat ed w it h int raperit oneal (shor t w hit e ar r ow ) and ret roperit oneal (long w hit e ar r ow ) hemorrhage. B: 7 c m superiorly , t here is a large mediast inal hemat oma surrounding t he aort a (shor t ar r ow ) and esophagus (long ar r ow ), w hic h has art if ac t f rom a nasogast ric t ube. At surgery , t horac ic aort ic t ransec t ion w as f ound w it h dissec t ion of hemorrhage int o t he ret roperit oneum and perit oneal c av it y . L, liv er, S, spleen.

AORTA–PATHOLOGIC CONDITIONS Atherosclerosis At herosc lerot ic c hanges of t he aort a c an be det ec t ed on CT sc ans. T hese inc lude c alc if ic at ion in t he w all, mild ec t asia, and t ort uosit y (F ig. 17- 7). Alt hough t he aort a usually is loc at ed in a prev ert ebral posit ion, it may lie t o t he side of t he spine P.1161 in pat ient s w it h sev ere at herosc lerosis. At heromat ous plaque and c hronic mural t hrombus may be low er in at t enuat ion v alue t han f low ing blood, but are best apprec iat ed on post c ont rast sc ans (F ig. 17- 8). Oc c lusion of a v essel likew ise is best demonst rat ed on post c ont rast sc ans (F ig. 17- 9).

F igure 17- 7 Aort ic t ort uosit y may mimic dissec t ion or f oc al aneury sm on axial images. A: Axial c ont rast - enhanc ed mult idet ec t or row c omput ed t omography

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2512

17 - Retroperitoneum sc an of t he upper abdomen. B: Coronal rec onst ruc t ion of t he v olume dat a show s aort ic t ort uosit y . A, Aort a; L, liv er; K, kidney .

F igure 17- 8 At heromat ous plaque in a normal- size aort a. T he at heroma (ar r ow ) has a low er at t enuat ion v alue and is c learly dif f erent iat ed f rom t he aort ic lumen on t his c ont rast - enhanc ed c omput ed t omography image.

At herosc lerot ic c hanges of t he aort a also c an be seen on MR images. Calc if ic at ion of t he aort ic w all appears as an arc or c irc umf erent ial rim of low signal int ensit y . On SE images, at heromat ous plaques and t hrombi produc e int raluminal signals of v arious int ensit ies. Whereas organized t hrombi hav e low signal int ensit ies on bot h T 1- and T 2- w eight ed SE images, f resh unorganized t hrombi hav e high signal int ensit ies on T 1- and T 2- w eight ed images (45). A f ibrous c ap ov er t he t hrombus t y pic ally has unif orm inc reased signal on T 2w eight ed imaging and show s enhanc ement on delay ed post gadolinium T 1w eight ed images (167). At heromat ous plaques and t hrombi c an be dif f erent iat ed easily f rom t he aort ic lumen, w hic h usually appears as an area of signal v oid. How ev er, slow blood f low may result in int raluminal signal. T he signal f rom slow f low c an be dist inguished f rom t hat of at heromat ous plaques

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2513

17 - Retroperitoneum and t hrombus by c omparing t he signal int ensit ies on f irst and sec ond ec ho images. Slow f low may show an inc rease in t he absolut e signal int ensit y on t he sec ond or ev en ec ho, w hereas t he signal produc ed by t hrombus and t he

at heromat ous plaque dec reases in int ensit y on t he sec ond ec ho. T his inc rease in signal st rengt h in blood v essels w it h slow f low has been desc ribed as an ev en- ec ho rephasing ef f ec t (31). On GRE images, at heromat ous plaque and t hrombi usually are less int ense t han f low ing blood. T he signal dif f erenc e bet w een at heromat ous plaque/t hrombus and f low ing blood is ac c ent uat ed on post gadolinium GRE images.

Penetrating Atherosclerotic Ulcer and Intramural Hematoma Penet rat ing at herosc lerot ic ulc ers (PAUs) f orm w hen an at herosc lerot ic lesion erodes t hrough t he int ernal elast ic lamina int o t he media. A f oc al c rat erlike out pouc hing or sac c ular aneury sm is c reat ed (116,197). Int ramural hemat oma or a loc alized dissec t ion c an t hen dev elop. Dist inguishing t his f rom primary aort ic dissec t ion may be dif f ic ult . T he ident if ic at ion of a c ont rast - f illed c rat er c ommunic at ing w it h t he aort ic lumen, an irregular t hic k int imal f lap, and t he limit ed ext ent of dissec t ion are helpf ul in dist inguishing a penet rat ing ulc er f rom a primary aort ic dissec t ion (347). Most penet rat ing ulc ers oc c ur in t he desc ending t horac ic aort a; how ev er, abdominal aort ic inv olv ement has been report ed (219). T he t y pic al c linic al present at ion is t hat of an elderly pat ient w it h c hest or bac k pain and hy pert ension. T he prognosis in c ases of penet rat ing ulc er is unc lear (51,110,116,151). Inc ident ally disc ov ered lesions may progress slow ly w it h a low prev alenc e of rupt ure. Pat ient s w it h persist ent pain or w it h larger lesions of t en hav e a w orse prognosis, w it h rapid enlargement , aneury sm f ormat ion, and rupt ure. Int ramural hemat oma may oc c ur eit her sec ondary t o a PAU or as a spont aneous bleed f rom v asa v asorum usually in a hy pert ensiv e pat ient (197). As w it h PAU, int ramural hemat oma is more c ommon in t he t horac ic aort a and may lead t o aort ic rupt ure or dissec t ion (328). PAU w it h int ramural hemat oma is f elt t o hav e a w orse prognosis w it h expansion of t he hemat oma and rupt ure, t han int ramural hemat oma alone (85,198). CT angiography (CT A) is usef ul in f ull ev aluat ion of t hese lesions. Mult iplanar rec onst ruc t ions demonst rat e t he ext ent of t he ulc er c av it y in PAU and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2514

17 - Retroperitoneum ac c ompany ing int ramural hemat oma. Alt hough int ramural hemat oma is hy perdense on nonc ont rast exams, it c annot be dist inguished f rom c hronic t hrombus by densit y alone but is indic at ed by inw ard displac ement of int imal c alc if ic at ion (151). Int ramural hemat oma also produc es smoot h ec c ent ric w all t hic kening t hat ext ends smoot hly in a longit udinal direc t ion, unlike t he more irregular at herosc lerot ic plaque. MRA has also been adv oc at ed f or ev aluat ion

of t hese lesions. Alt hough ac ut e int ramural hemat oma (w it hin t he f irst 7 day s) may hav e int ermediat e signal int ensit y similar t o t hat of musc le, subac ut e hemorrhage has inc reased T 1 and T 2 signals (198). At herosc lerot ic plaque and c hronic t hrombus exhibit low t o int ermediat e signal on bot h T 1 and T 2 sequenc es (368).

Stenosis and Occlusion Oc c lusion and st enosis of t he aort a or it s primary branc hes is most c ommonly due t o at herosc lerot ic c hange, alt hough an art erit is suc h as T akay asu art erit is c an also produc e dramat ic c hanges.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2515

17 - Retroperitoneum

F igure 17- 9 At herosc lerosis w it h oc c lusion of t he dist al aort a. A: Axial c ont rast - enhanc ed c omput ed t omography sc an show s at herosc lerosis w it h plaque and t hrombus in t he abdominal aort a. B: Complet e oc c lusion oc c urs at t he lev el of t he c rossing duodenum.C : Coronal rec onst ruc t ion. I, inf erior v ena c av a; U, unc inat e proc ess of panc reas; D, duodenum; ar r ow , aort a.

P.1162 Luminal narrow ing of t he aort a and it s branc h v essels c an be w ell seen on helic al CT angiograms using MIP and v olume- rendering t ec hniques (VRT s) (see F ig. 17- 9). In one st udy perf ormed w it h a single- det ec t or row CT sc anner (283), CT A depic t ed all main and ac c essory renal art eries t hat w ere seen w it h c onv ent ional art eriography . CT A w as also 92% sensit iv e and 83% spec if ic f or t he det ec t ion of renal art ery st enosis w hen t he st enosis w as great er t han or equal t o 70%. In anot her st udy perf ormed w it h an MDCT sc anner, CT A w as 92% sensit iv e and 99% spec if ic f or t he det ec t ion of hemody namic ally signif ic ant st enosis of aort oiliac and renal art eries (355). Underest imat ion or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2516

17 - Retroperitoneum ov erest imat ion of art erial st enosis may oc c ur on CT angiograms due t o v essel w all c alc if ic at ions (283,355). T his problem is exac erbat ed on MIP images, w hic h display only t he v oxels w it h t he highest signal int ensit y along parallel ray s, t hereby obsc uring t he t rue art erial lumen. T he use of mult iple MIP images generat ed about bot h x and z axes is needed t o ensure t hat t he t rue lumen is apprec iat ed (283). T he use of a w ide w indow w idt h (w indow w idt h, 2,000 HU) and a high w indow lev el (c ent er lev el, 500 HU) f or ev aluat ing all art erial segment s c ont aining c alc ium is also suggest ed t o minimize t he “ blooming” ef f ec t f rom t he c alc ium (355).

St enosis of t he aort a, iliac v essels, and renal art eries c an also be depic t ed on eit her nonc ont rast - or gadolinium- enhanc ed MR angiograms w it h a high degree of ac c urac y . Bec ause it ov erc omes t he inherent problems of T OF and phasec ont rast t ec hniques, gadolinium- enhanc ed MRA has bec ome our t ec hnique of c hoic e (142). Sensit iv it ies and P.1163 spec if ic it ies bet w een 90% and 100% hav e been ac hiev ed w it h c ont rast enhanc ed 3D MRA f or t he det ec t ion of hemody namic ally signif ic ant st enosis of aort oiliac and renal art eries (107,308,355) Bot h MRI and CT c an show t he v essel w all t hic kening c harac t erist ic of T akay asu art erit is (159,204).

Aortic Aneurysm In general, t he abdominal aort a is c onsidered aneury smally dilat ed if it exc eeds 3 t o 3.5 c m in maximal diamet er or if t he inf rarenal aort a is at least 5 mm larger t han t he renal aort a or if a loc alized dilat ion of t he aort a is present (126,297). Abdominal aort ic aneury sms (AAAs) great er t han or equal t o 29 mm in maximal diamet er are f ound in approximat ely 6% of men and 1% of w omen age 55 t o 65 y ears and inc rease in prev alenc e by about 6% per dec ade t hereaf t er in men and 1.5% per dec ade in w omen (297). Aneury sms great er t han 3.9 c m in diamet er oc c ur in 1% of men and in 0.1% of w omen f rom 55 t o 64 y ears of age and inc rease by 3% t o 4% per dec ade t hereaf t er in men and 0.3% t o 0.6% per dec ade in w omen (297). T he inc idenc e of AAA has inc reased in t he last 50 y ears, likely a result , in part , of improv ed det ec t ion rat es w it h t he adv ent of modern imaging modalit ies. Smoking hist ory is t he st rongest risk f ac t or in t he dev elopment of AAA w it h an odds rat io of f rom 1.4 t o 8, depending on t he durat ion of smoking (177,297).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2517

17 - Retroperitoneum In t he Unit ed St at es, AAAs are most ly t o t he result of at herosc lerosis (F ig. 17- 10). Inf ec t ious (my c ot ic , sy philit ic ), inf lammat ory (e.g., T akay asu art erit is), c ongenit al (e.g., Marf an sy ndrome), or t raumat ic c auses are unc ommon. T he v ast majorit y of AAAs are inf rarenal in loc at ion. T he applied pressure load in t his loc at ion is great er bec ause of t he t apering geomet ry of t he aort a and ref lec t ed pressure w av es f rom t he aort ic bif urc at ion (62). F ollow ing LaPlac e's law , in w hic h w all t ension inc reases geomet ric ally w it h radius, larger aneury sms t end t o grow at a more rapid rat e t han smaller ones. In one st udy (190), t he annual grow t h rat es f or aneury sms less t han 4 c m,

bet w een 4 and 5 c m, and great er t han 5 c m in diamet er w ere 5.3 mm, 6.9 mm, and 7.4 mm, respec t iv ely . Similarly , t he inc idenc e of rupt ure v aries direc t ly w it h t he size of t he aneury sm. Whereas t he inc idenc e of rupt ure is negligible f or aneury sms less t han 3.9 c m in diamet er, t he risk exc eeds 20% annually f or aneury sms larger t han 5 c m in diamet er (190). It is import ant t o not e t hat , f or a giv en diamet er, t he risk of rupt ure is f our t imes higher in w omen t han in men, perhaps ref lec t ing t he generally smaller init ial diamet er of t he aort a in w omen. Henc e, t he t hreshold f or int erv ent ion in w omen should be somew hat low er t han f or men (244,253). Comput er modeling of 3D shape and c alc ulat ion of w all st ress may also hav e a role in t he predic t ion of rupt ure, but at present t his t ec hnique is st ill experiment al (77,78). Ac c ept ed indic at ions f or repair of AAAs inc lude size great er t han 5 t o 5.5 c m, rapid rat e of aneury sm expansion (inc rease of 5 mm or more in 6 mont hs), know n my c ot ic aneury sm, pain, c onc omit ant oc c lusiv e disease, iliac or f emoral art ery aneury sms, and peripheral emboli (34,244,295).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2518

17 - Retroperitoneum

F igure 17- 10 Mural t hrombus w it h c alc if ic at ion in an abdominal aort ic aneury sm. Cont rast - enhanc ed c omput ed t omography sc an show s a 7- c mdiamet er abdominal aort ic aneury sm. Wit hin t he mural t hrombus, t here are c alc if ic at ions (shor t ar r ow s) t hat are dist inc t f rom t he int ac t rim of int imal c alc if ic at ion (long ar r ow s). T his is in c ont radist inc t ion t o t he displac ed int imal c alc if ic at ion t hat may be seen in aort ic dissec t ion, in w hic h c ase t he peripheral rim of int imal c alc if ic at ion is disrupt ed or dist ort ed. I, inf erior v ena c av a; D, duodenum.

AAAs c an be det ec t ed and dif f erent iat ed f rom a t ort uous aort a by CT . Measurement s of aort ic diamet er obt ained on CT c orrelat e w ell w it h t hose f ound at surgery (239). CT measurement s are f airly reproduc ible. In one st udy , absolut e int raobserv er v ariat ion in measurement s of maximal inf rarenal aort ic diamet er w as 2 mm or less in 94% of c ases. Int erobserv er v ariat ion w as somew hat great er but w as st ill 2 mm or less in 82% (298). Alt hough not large, t hese f igures suggest t hat w hen assessing c hange in aort ic diamet er, prior CT sc ans should be rev iew ed c ont emporaneously w it h t he new st udy t o reduc e int erobserv er error (298). T he origin and t he lengt h of an aneury sm as w ell as it s relat ionship t o renal and iliac art eries c an be t rac ed on bot h serial axial

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2519

17 - Retroperitoneum

sc ans and rec onst ruc t ed images w it h MIP and VRT projec t ional CT angiograms (F ig. 17- 11). When 10- mm sec t ions are used, v olume av eraging of a t ort uous juxt arenal aneury sm may produc e an appearanc e suggest ing inv olv ement of t he main renal art eries w hen in f ac t t hese v essels are ac t ually uninv olv ed. How ev er, w it h 2- t o 5- mm sec t ions, t he ov erall ac c urac y of helic al CT in predic t ing aneury smal loc at ion w it h respec t t o t he renal art eries is P.1164 quit e high (256,332). T he abilit y t o ident if y renal art ery st enosis of great er t han 70% has also improv ed signif ic ant ly w it h t he use of t hin c ollimat ion helic al CT t ec hnique (256,332). CT angiograms obt ained on MDCT now prov ide all t he inf ormat ion required f or t he planning of repair of an AAA.

F igure 17- 11 Inf rarenal aort ic aneury sm. A: Cont rast - enhanc ed axial image show s normal c aliber of aort a (ar r ow head) at t he lev el of t he unusually high origin of t he renal art eries (ar r ow s). L, liv er; S, spleen. B: Aneury sm is show n at t he inf rarenal lev el w it h at herosc lerot ic c hanges (ar r ow heads). L, liv er; K, kidney . C : Sagit t al maximum- int ensit y projec t ion (MIP) image show s t ort uous aort a w it h aneury sm and at herosc lerot ic c hanges (ar r ow s). S, spine. D: Coronal MIP image show s t ort uous aort a and aneury sm. E: Coronal v olumerendered image show s inf rarenal aneury sm (ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2520

17 - Retroperitoneum MRI using c onv ent ional T 1- and T 2- w eight ed SE or GRE sequenc es is also an ac c urat emet hod f or demonst rat ing AAAs. It c an ac c urat ely depic t t he size of an aneury sm and t he aort ic lumen, it s relat ionship t o t he origin of t he renal art eries, and t he st at usof t he iliac art eries. How ev er, t hese nonc ont rast

t ec hniques do not reliably det ec t ac c essory renal art eries or depic t assoc iat ed oc c lusiv e disease of aort ic branc h v essels, know ledge of w hic h is import ant f or aneury sm repair. Cont rast - enhanc ed 3D MRA perf ormed in a breat h- hold prov ides prec ise inf ormat ion regarding t he aort ic lumen as w ell as it s relat ionship t o aort ic branc h v essels (F ig. 17- 12). Sev eral st udies hav e show n t hat c ont rast - enhanc ed 3D MRA has a high sensit iv it y and spec if ic it y f or det ec t ion of hemody namic ally signif ic ant st enosis of renal and iliac art eries (142,355). Alt hough bot h CT and MRI c an det ec t t he presenc e and t he size of aort ic aneury sms and t heir int ernal c harac t er w it h a high degree of ac c urac y , ult rasound (US) remains P.1165 t he proc edure of c hoic e in pat ient s w it h suspec t ed AAA bec ause of it s ease of perf ormanc e, lac k of ionizing radiat ion, low er c ost , and port abilit y (43,357). In pat ient s w ho hav e had an unsuc c essf ul or equiv oc al sonographic examinat ion bec ause of post surgic al sc ar t issue, obesit y , or abundant bow el gas, or in pat ient s needing c omplet e preoperat iv e assessment , eit her a CT or an MRI st udy may be perf ormed. In most c ases, w e pref er CT t o MRI bec ause of it s bet t er spat ial resolut ion and ease of perf ormanc e. Opt imal CT ev aluat ion of t he abdominal aort a, how ev er, requires int rav enous c ont rast mat erial, f or example, t o dif f erent iat e a pseudoaneury sm f rom periaort ic ly mphadenopat hy . T hus, in pat ient s w ho hav e a c ont raindic at ion t o t he use of iodinat ed c ont rast mat erial, it is adv ant ageous t o perf orm MRI rat her t han a CT examinat ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2521

17 - Retroperitoneum

F igure 17- 12 Inf rarenal aort ic aneury sm. A: Prec ont rast axial T 1- w eight ed magnet ic resonanc e image (MRI) show s t hrombus (ar r ow ) in t he aort ic aneury sm. K, kidney s. B: Post c ont rast axial T 1- w eight ed MRI show s nonopac if ic at ion of t he t hrombus (ar r ow s) in t he aort ic aneury sm. K, kidney s; S, spine. C : Coronal half F ourier snap shot t urbo spin ec ho MRI of abdomen show s aort ic aneury sm (ar r ow s). L, liv er.

Inflammatory AAA Inf lammat ory AAA (IAAA) is diagnosed w hen a dense f ibrot ic and f requent ly highly v asc ular reac t ion is not ed surrounding an AAA (F ig. 17- 13). T hese c hanges may inf ilt rat e surrounding st ruc t ures suc h as t he duodenum, IVC, lef t P.1166 renal v ein, uret ers, mesent ery , and small bow el. Approximat ely 3% t o 15% of all AAAs are c omplic at ed by inf lammat ory c hange. IAAAs oc c ur more c ommonly in men t han in w omen and t y pic ally present at a y ounger age t han noninf lammat ory AAAs. Sy mpt oms are usually present and inc lude abdominal or bac k pain, w eight loss, and an elev at ed ery t hroc y t e sediment at ion rat e (132,206,228,266). Alt hough t he pat hogenesis of IAAA is unc lear, an immune response t o some c omponent of t he art erial w all or at herosc lerot ic plaque has

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2522

17 - Retroperitoneum been suggest ed. T he t ime nec essary f or t he dev elopment of t he inf lammat ory

response is also unc ert ain; how ev er, t he dev elopment of an inf lammat ory AAA f rom an unc omplic at ed aneury sm ov er a period of 6ВЅ mont hs has been doc ument ed by CT (176). In many c ases, a dec rease in t he amount of f ibrosis oc c urs f ollow ing aneury sm repair (228,248,305).

F igure 17- 13 Perianeury smal f ibrosis. Nonc ont rast c omput ed t omography sc an show s an inf rarenal abdominal aort ic aneury sm assoc iat ed w it h a sharply marginat ed rind of f ibrot ic sof t t issue (ar r ow s).

CT has been report ed t o hav e v ariable sensit iv it y and spec if ic it y f or t he det ec t ion of IAAAs, ranging f rom approximat ely 50% t o 80% (132,316). IAAAs usually appear as an AAA surrounded by a sy mmet ric sof t t issue mass or w all t hic kening w it h relat iv e sparing of t he post erior aort ic w all (132). T he mass is usually w ell def ined, alt hough a more inf ilt rat iv e appearanc e is oc c asionally seen (14). T he mass/w all t hic kening w ill demonst rat e lat e phase c ont rast enhanc ement on bot h CT and MRI. On c ont rast - enhanc ed MRI, a low - int ensit y int ernal rim w it h no enhanc ement has been not ed and is t hought t o represent t hic kened int ima bet w een inf lammat ory mass and t he aort ic lumen (115). T hree or more alt ernat ing lay ers of high and low signal hav e also been not ed in t he inf lammat ory t issue on MRI. T hese c hanges w ere most prominent on nonc ont rast short t au inv ersion rec ov ery (ST IR) sequenc es but w ere also not ed on T 1- w eight ed sequenc es (315). Ot her aut hors hav e report ed only an int ermediat e signal on T 1- w eight ed sequenc es w it h poor dist inc t ion f rom an int raluminal t hrombus (342).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2523

17 - Retroperitoneum

F igure 17- 14 My c ot ic aort ic aneury sm:A: Nonc ont rast –enhanc ed c omput ed t omography (CT ) image show s a large sof t t issue mass (M) adjac ent t o t he c alc if ied desc ending aort a. T his c ould be c onf used w it h ly mphadenopat hy . B: Cont rast - enhanc ed CT sc an demonst rat es enhanc ement of t his mass t o t he same degree as t he aort a, t hus est ablishing it s v asc ular nat ure.

Mycotic Aneurysm My c ot ic aneury sms f orm as a result of inf ec t ious inf lammat ion c ausing w eakening or nec rosis of t he aort ic w all. T he inf ec t ion may oc c ur f rom direc t seeding of t he roughened at herosc lerot ic surf ac e, by sept ic emboli t o t he v asa v asorum, or f rom c ont iguous spread f rom an adjac ent ext rav asc ular sourc e suc h as a v ert ebral ost eomy elit is or disc it is. About half of pat ient s in one series had a hist ory of rec ent inf ec t ion, w hic h presumably ac t ed as a bac t eremic sourc e (231). Immunoc ompromised pat ient s also are more susc ept ible t o t he dev elopment of my c ot ic aneury sms (221,231). T y pic al present at ion inc ludes pain, f ev er, leukoc y t osis, and a posit iv e blood c ult ure. Bac t eria c ause most my c ot ic aneury sms, w it h St aphy loc oc c us aur eus being t he most c ommon agent . Salm onella and St r ept oc oc c us spec ies and Esc her ic hia c oli are also f requent (221,231). Unlike at herosc lerot ic aneury sms, 85% of w hic h inv olv e t he inf rarenal aort a, my c ot ic aneury sms are more ev enly dist ribut ed w it h approximat ely 35% t o 40% being inf rarenal (196). A my c ot ic aneury sm usually is sac c ular and has a lobulat ed c ont our (F igs. 1714 and 17- 15). A periaort ic sof t t issue mass or st randing and/or f luid is f requent ly present . Gas is present inf requent ly , but w hen seen, is v irt ually pat hognomic f or inf ec t ion (F ig. 17- 16). Calc if ic at ion c an oc c ur in my c ot ic aneury sms, but t his is less c ommon t han in at herosc lerot ic aneury sms (196).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2524

17 - Retroperitoneum Similarly , t he absenc e of at herosc lerot ic c hange in ot her v essels point s t o a my c ot ic et iology . Rapid dev elopment or enlargement of a my c ot ic aneury sm may be not ed if sequent ial sc ans are perf ormed (196,366). Erosion of t he adjac ent v ert ebral body may also be seen but is inf requent (196). Nonaneury smal bac t erial aort it is has also been desc ribed and c an lead t o rupt ure. A hazy periaort ic densit y c ont aining gas is t he c harac t erist ic CT f inding and should prompt aggressiv e management (201).

F igure 17- 15 My c ot ic aneury sm. A: Cont rast - enhanc ed c omput ed t omography (CT ), sagit t al rec onst ruc t ion, show s a sac c ular aneury sm (ar r ow s) c oming of f t he inf rarenal aort a w it h a sec ond aneury sm arising at t he lev el of t he right renal art ery (ar r ow head). B: Axial CT image show s t he break in int imal c alc if ic at ion (ar r ow ) w it h sac c ular aneury sm (ar r ow heads). C : Angiogram show s a lobular inf rarenal aneury sm (ar r ow ) w it h a smaller aneury sm adjac ent t o t he origin of t he right renal art ery (arrow head).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2525

17 - Retroperitoneum

F igure 17- 16 Inf ec t ed at herosc lerot ic aort ic aneury sm. Numerous air bubbles are seen w it hin t he w all of t his f usif orm aneury sm.

P.1167 P.1168

Ruptured AAA Rupt ured AAA c an be a dif f ic ult c linic al diagnosis. Less t han one t hird of pat ient s w it h rupt ured AAAs present w it h t he c lassic t riad of abdominal pain, bac k pain, and a pulsat ile mass (202). Ov er half of pat ient s in one series w ere init ially misdiagnosed (2). Conv ersely , up t o t w o t hirds of hemody namic ally st able pat ient s w it h know n AAAs and abdominal pain do not t urn out t o hav e a rupt ured aneury sm (173). T he c linic al present at ion of renal c olic , div ert ic ulit is, bow el isc hemia, c holec y st it is, pept ic ulc er disease, and ac ut e my oc ardial inf arc t ion hav e all been show n bot h t o mimic and t o be mimic ked by rupt ured AAA (2,173,202). CT is a usef ul and ef f ec t iv e imaging st udy f or ev aluat ing hemody namic ally st able pat ient s w it h suspec t ed leaking AAAs. In t his group of pat ient s, t he delay imposed by obt aining a preoperat iv e CT st udy usually does not adv ersely af f ec t pat ient out c ome, and t he inf ormat ion obt ained f rom t he CT st udy c an bot h make an alt ernat iv e diagnosis or c onf irm a diagnosis and aid subst ant ially in bot h preoperat iv e and int raoperat iv e management (53,173,295). T he CT diagnosis of rupt ured AAA is based on demonst rat ion of irregular, highdensit y mat erial c orresponding t o blood (approximat ely +70 HU on nonc ont rast sc ans) inf ilt rat ing t he periaort ic f at and ext ending int o t he adjac ent perirenal and less c ommonly pararenal spac es (F ig. 17- 17). T he aort a may be ant eriorly displac ed by t he mass or c ollec t ion. Alt hough int rav enous c ont rast mat erial is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2526

17 - Retroperitoneum not required f or t he diagnosis of rupt ured AAA, c ont rast - enhanc ed CT may doc ument ac t iv e art erial ext rav asat ion eit her as a f oc al high densit y area (at t enuat ion v alues 80 t o 130 HU) surrounded by a large hemat oma or as a

dif f use area of high densit y (140) (F igs. 17- 17 and 17- 18). Addit ional f indings inc lude ant erior displac ement of t he kidney by t he hemat oma and enlargement or obsc urat ion of t he psoas musc le. A f oc ally indist inc t aort ic margin on c ont rast - enhanc ed sc ans and f oc al disc ont inuit y of a c irc umf erent ially c alc if ied rim may indic at e t he sit e of rupt ure, but neit her sign is spec if ic (84,296) (F igs. 17- 19 and 17- 20). Rupt ure loc at ion is most c ommonly post erolat eral, alt hough t his may not alw ay s be ident if iable if t here is a large amount of hemorrhage present (79). Oc c asionally blood f rom a rupt ured AAA may ext end int o t he perit oneal c av it y . F ree f luid w it h at t enuat ion v alue great er t han 30 HU and t he presenc e of a hemat oc rit ef f ec t suggest a hemoperit oneum (27).

F igure 17- 17 Rupt ured abdominal aort ic aneury sm. A: Cont rast - enhanc ed c omput ed t omography sc an show s irregular sof t t issue st rands represent ing ac ut e hemorrhage (H) ext ending f rom t he aneury sm (A) int o t he lef t perirenal spac e. Not e t he t hic kened perirenal f asc ia (ar r ow s). B: 5 c m c audad, ac ut e hemorrhage (H) is hy perdense c ompared w it h psoas musc le (P). Not e t he irregular int raluminal t hrombus (ar r ow ) w it hin t he aort a.

F alse–posit iv e CT diagnoses of rupt ured AAAs are unc ommon; how ev er, a v ariet y of ret roperit oneal masses, suc h as an opac if ied duodenum, ly mphadenopat hy , perianeury smal f ibrosis, and masses in t he psoas musc le are oc c asionally seen in pat ient s w it h AAAs and may be c onf used w it h areas of rupt ure. Ret roperit oneal hemorrhage may also oc c ur f or reasons unc onnec t ed t o t he AAA, suc h as ant ic oagulat ion or neoplasm. Suc h unrelat ed hemorrhage

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2527

17 - Retroperitoneum may be suspec t ed if t he aort ic w all is int ac t , w ell v isualized, and has an int ac t periaort ic f at plane (295). Alt hough f alse–negat iv e CT diagnoses are unc ommon, it should be not ed t hat pat ient s w it h impending or c ont ained rupt ure may present w it h pain but show no obv ious hemorrhage. Bec ause of t his, pat ient s w it h large AAAs and

unexplained abdominal or bac k pain should be admit t ed and c onsiderat ion giv en t o semielec t iv e repair (98,295). P.1169 Sev eral CT signs of c ont ained or impending rupt ure hav e also been desc ribed. T he “ draped aort a” sign oc c urs w hen t he post erior aort ic w all is not def inable and t he post erior margin of t he aort a is c losely applied t o and f ollow s t he c ont our of t he v ert ebral body (106). T he presenc e of a c resc ent shaped area of high at t enuat ion w it hin t he w all or mural t hrombus of t he aneury sm has been assoc iat ed w it h an int ramural hemat oma and is predic t iv e of f ree or c ont ained rupt ure of an AAA (10,296). In one st udy , t he “ c resc ent sign” had a 77% sensit iv it y and 93% spec if ic it y f or rupt ure or int ramural hemat oma (208) (F ig. 17- 21). T he presenc e of eit her of t hese signs should raise t he suspic ion of impending or c ont ained rupt ure part ic ularly in pat ient s w it h abdominal or bac k pain (208,296). T he amount of t hrombus present and t he c irc umf erenc e of t he AAA inv olv ed by t hrombus hav e not been show n t o be dif f erent in pat ient s w it h rupt ured and nonrupt ured AAAs (79).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2528

17 - Retroperitoneum

F igure 17- 18 Rupt ured abdominal aort ic aneury sm. A: Cont rast - enhanc ed axial c omput ed t omography image show s normal aort a at renal art ery (ar r ow ) lev el. Ret roperit oneal hemat oma f rom rupt ured inf rarenal aort ic aneury sm (ar r ow heads). K, kidney s. B: Rupt ured inf rarenal aort ic aneury sm w it h ac t iv e ext rav asat ion (ar r ow s) of c ont rast int o t he ret roperit oneum. Large ret roperit oneal hemat oma is on t he lef t side (ar r ow heads). AA, aort ic aneury sm. C : Ext ension of ret roperit oneal hemat oma (H) in t he pelv is. D: Coronal image show s rupt ured aort ic aneury sm w it h ac t iv e ext rav asat ion (ar r ow s). Ret roperit oneal hemat oma (H) ext ends int o t he lef t pelv is. L, liv er.

Bec ause of it s relat iv ely long imaging t ime and t he dif f ic ult y in monit oring c rit ic ally ill pat ient s, MRI has not been used t o ev aluat e pat ient s w it h suspec t ed rupt ure of AAAs. F urt hermore, MRI c annot dist inguish ac ut e hemat oma f rom ot her f luid c ollec t ions bec ause of t heir similar signal int ensit ies.

Chronic Pseudoaneurysm

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2529

17 - Retroperitoneum

In c omparison w it h ac ut e rupt ure, a c hronic pseudoaneury sm (f alse aneury sm) appears as a w ell- def ined, P.1170 P.1171 usually round, mass w it h an at t enuat ion v alue similar t o or low er t han t hat of t he nat iv e aort a on nonc ont rast sc ans. On post c ont rast sc ans, t he lumen of t he aneury sm as w ell as it s c ommunic at ion w it h t he aort a may enhanc e (F ig. 17- 22).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2530

17 - Retroperitoneum

F igure 17- 19 Rupt ured abdominal aort ic aneury sm t reat ed w it h endov asc ular st ent ing. A: Cont rast - enhanc ed c omput ed t omography show s normal aort a (ar r ow s) at renal art erial lev el. Not e ret roperit oneal hemat oma sec ondary t o rupt ured inf rarenal aneury sm (ar r ow heads). K, kidney . B: Rupt ured aort ic aneury sm (ar r ow s) w it h ret roperit oneal hemat oma (ar r ow heads). C : Large ret roperit oneal hemat oma ext ending int o pelv is f rom a rupt ured aneury sm (ar r ow heads). D: Post endograf t prec ont rast c oronal T 1- w eight ed magnet ic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2531

17 - Retroperitoneum resonanc e image (MRI) show s st ent (ar r ow s) in plac e. H, residual pelv ic hemat oma f rom rec ent aneury sm rupt ure. E: Post c ont rast c oronal MRI show s st ent (ar r ow s) in plac e.

F igure 17- 20 Rupt ured abdominal aort ic aneury sm. A: Cont rast - enhanc ed axial c omput ed t omography image at renal art erial lev el show s at herosc lerot ic c hanges in normal c aliber aort a (ar r ow s). Ret roperit oneal hemat oma ant erior t o aort a f rom rupt ured inf rarenal aort ic aneury sm (ar r ow head). K, kidney s; S, spine. B: Inf rarenal aort ic aneury sm w it h t hrombus and break in c alc if ic at ion ant eriorly (ar r ow s) and ret roperit oneal hemat oma (ar r ow heads) result ing f rom rupt ured aneury sm. C : Aort ic aneury sm w it h ac t iv e ext rav asat ion in t he aneury sm sac (ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2532

17 - Retroperitoneum

F igure 17- 21 High- at t enuat ing c resc ent in early rupt ure of an aort ic aneury sm. Non–c ont rast - enhanc ed c omput ed t omography sc an show s an abdominal aort ic aneury sm (A) w it h a high- at t enuat ing c resc ent (ar r ow heads) post erolat erally . Emergent surgery in t his 82- y ear- old w oman w it h bac k pain disc losed v ery early aneury sm rupt ure at t his sit e. (Court esy of Jay Heiken, St . Louis, Missouri.)

Aortoenteric Fistula Aort oent eric f ist ula (AEF ) is most c ommon in it s sec ondary f orm in w hic h c ommunic at ion bet w een an aort ic graf t and adjac ent bow el dev elops. Primary AEF , in w hic h suc h c ommunic at ion oc c urs bet w een nat iv e aort a and adjac ent bow el, is rare. In ov er half of c ases, t he dist al duodenum is t he inv olv ed bow el segment , alt hough inv olv ement of t he jejunum, ileum, and t ransv erse c olon has also been report ed (40,195). Mec hanic al erosion of an aneury sm or graf t int o t he adjac ent bow el w it h sec ondary inf ec t ion is t he usual et iology (333). Preexist ing sept ic aort it is, radiot herapy , or t umor are more unusual c auses (36). Massiv e gast roint est inal hemorrhage is t he most c ommon sy mpt om and is usually prec eded by a smaller self - limit ed bleed. F ev er, leukoc y t osis, and pain are also f requent sy mpt oms (36). Diagnosis c an be dif f ic ult and is f requent ly based on bot h endosc opy and CT . CT f indings suspic ious f or AEF inc lude perianeury smal (or perigraf t ) sof t t issue, f luid, and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2533

17 - Retroperitoneum gas in t he spac e bet w een t he aort a and duodenum (F igs. 17- 23 and 17- 24). Duodenal P.1172 f old t hic kening may also be not ed (195). High- densit y c lot or ext rav asat ed c ont rast may be v isualized w it hin t he adjac ent bow el in c ases w it h int raluminal or int ramural hemorrhage (255,370). F or t his reason, it is suggest ed t hat w at er be used inst ead of oral c ont rast in pat ient s if AEF is a diagnost ic c onsiderat ion (255). On oc c asion, minimal or no CT f indings are present ; henc e, a negat iv e CT does not ent irely prec lude t he possibilit y of AEF (195).

Aortocaval Fistula Aort oc av al f ist ulae are rare. T he most c ommon c ause is rupt ure of an AAA int o t he adjac ent IVC. T rauma, eit her iat rogenic or penet rat ing injury f rom a gunshot or st ab w ound, also c auses f ist ulae. T he most c ommon sy mpt om is an abdominal bruit w it h bac k pain and shoc k as c ommon ac c ompaniment s. Sev ere leg sw elling, sc rot al edema, and renal insuf f ic ienc y and hemat uria are also not ed f rom t he induc ed peripheral and pelv ic v enous hy pert ension (56). T he CT f indings t hat suggest t his diagnosis inc lude periv asc ular st randing around t he IVC and f ist ulous t rac t and simult aneous enhanc ement of t he aort a and IVC (F ig. 17- 25). T he IVC and iliac v eins are not ed t o be dist ended. Ret rograde opac if ic at ion of t he renal v eins and perirenal st randing may also be observ ed (54,327). Similar f indings hav e been report ed on gadoliniumenhanc ed MRA (83). Alt hough MRA t akes longer t o perf orm, it s use may be indic at ed if renal insuf f ic ienc y is present .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2534

17 - Retroperitoneum

F igure 17- 22 Aort ic aneury sm and assoc iat ed c hronic pseudoaneury sm. A: Post c ont rast c omput ed t omography image demonst rat es a large abdominal aort ic aneury sm ext ending post erolat erally int o t he lef t parav ert ebral area. Not e t he c ent rally enhanc ed lumen in bot h t he t rue (ar r ow ) and t he f alse (ar r ow head) aneury sms. T he low er densit y periphery represent s eit her an at heroma or a t hrombus. T he lef t psoas musc le is obsc ured by t he pseudoaneury sm. B: T he abdominal art eriogram show s f indings similar t o t hose of t he CT st udy .

Aortic Dissection Dissec t ion of t he aort a t y pic ally oc c urs w hen blood ent ers an int imal t ear and progressiv ely separat es t he int ima f rom t he underly ing remainder of t he w all.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2535

17 - Retroperitoneum Alt ernat iv ely , dissec t ion may begin w it h an int ramural bleed t hat rupt ures t hrough t he int ima t o c ommunic at e w it h t he lumen.

F igure 17- 23 Aort it is w it h dev elopment of aort oent eric f ist ula. A: Init ial c ont rast - enhanc ed c omput ed t omography show s poorly c irc umsc ribed inc reased sof t t issue around t he ant erior margin of t he aort a (ar r ow ). P, panc reas; D, duodenum. B: T w o w eeks lat er, f ollow ing plac ement of an endograf t , t here is inc reased ant erior sof t t issue w it h air not ed about t he aort a and ext ending int o t he ant erior pararenal spac e (ar r ow heads), indic at iv e of aort ic rupt ure w it h hemat oma and inf ec t ion. P, panc reas; D, duodenum. C : Sev en w eeks lat er, f ollow ing plac ement of an addit ional endograf t , t here is air in t he graf t (arrow head) w it h c ont inuing pain, f ev ers, and gast roint est inal bleeding c onsist ent w it h ongoing graf t inf ec t ion and aort oent eric f ist ula. Nasogast ric t ube (ar r ow s) marks t he loc at ion of t he duodenum. P, panc reas.

P.1173 In t he v ast majorit y of c ases, dissec t ion begins in t he t horac ic aort a. Isolat ed abdominal aort ic inv olv ement oc c urs in only 1% t o 2% of dissec t ion c ases (73). Classif ic at ion of dissec t ion depends on t he sit e of origin w it h St anf ord

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2536

17 - Retroperitoneum t y pe A lesions beginning proximal t o t he lef t subc lav ian art ery and t y pe B lesions st art ing dist al t o t his v essel. Hy pert ension is t he dominant predisposing f ac t or, alt hough diseases t hat af f ec t w all int egrit y , suc h as

Marf an sy ndrome, T urner sy ndrome, Ehlers- Danlos sy ndrome, and c y st ic medial nec rosis also play a role. Ot her assoc iat ions inc lude bic uspid aort ic v alv e, art erit is, and t rauma (303). Dissec t ion limit ed t o t he aort a present s c lassic ally w it h abrupt onset of sharp, sev ere midline pain. In lesions inv olv ing t he asc ending aort a, pain is f requent ly ant erior, w hile w it h desc ending aort ic inv olv ement , pain is c ommonly post erior (104,303). If branc h v essels w it hin t he abdomen are inv olv ed, isc hemic damage t o a v ariet y of organs may oc c ur and produc e addit ional sy mpt oms (291). Diagnosis c an be dif f ic ult and in one series w as missed in 38% of pat ient s on init ial c linic al ev aluat ion and only est ablished at aut opsy in 11% (303). T he goal of imaging in aort ic dissec t ion is t o v erif y t he diagnosis, ident if y t he t y pe of dissec t ion, ident if y t he t rue and f alse lumen, and est ablish t he ext ent of disease and presenc e of c omplic at ions suc h as c ompromise of branc h v essels (356). T he diagnosis of an aort ic dissec t ion is based on demonst rat ion of an int imal f lap w it h enhanc ement of bot h t he t rue and f alse lumina af t er int rav enous administ rat ion of c ont rast medium. T he t rue lumen c an of t en be ident if ied by it s c ont inuit y w it h t he undissec t ed aort ic lumen. When t his observ at ion is not av ailable sev eral ot her markers hav e been desc ribed t o separat e t he t rue lumen f rom t he f alse lumen. In general, t he f alse lumen is larger t han t he t rue lumen and more likely t o c ont ain t hrombus. T he “ beak” sign is a marker f or t he f alse lumen and oc c urs w hen t here is an ac ut e angle bet w een t he int imal f lap and t he out er w all (182). T his angle may be enhanc ed or c ont ain t hrombus. Aort ic “ c obw ebs,” most likely represent ing P.1174 residual ribbons of media t hat hav e been inc omplet ely sheared f rom t he aort ic w all during t he dissec t ion proc ess, are oc c asionally seen, and serv e as an anat omic marker of t he f alse lumen (352). Markers of t he t rue lumen inc lude more rapid enhanc ement , out er w all c alc if ic at ion, and ec c ent ric f lap c alc if ic at ion. T his lat t er oc c urs w hen t here is c alc if ic at ion on one side of t he int imal f lap. T he lumen f ac ing t hat side is t he t rue lumen (182,291).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2537

17 - Retroperitoneum

F igure 17- 24 Aort oent eric f ist ula f ollow ing open repair of an abdominal aort ic aneury sm. A: Int rav enous c ont rast –enhanc ed c omput ed t omography sc an show s an air and f luid c ollec t ion (arrow head) c onsist ent w it h absc ess sit t ing bet w een aort ic graf t (A) and small bow el (ar r ow ). B: Absc ess (arrow head) ext ends c audally in f ront of bilimbed port ion of graf t (ar r ow ).

When t he f alse lumen does not f ill w it h c ont rast medium, a diagnosis of aort ic dissec t ion st ill may be suggest ed if inw ard displac ement of int imal c alc if ic at ion is present . How ev er, it may not alw ay s be possible t o dist inguish t hrombus c alc if ic at ion f rom displac ed c alc if ied int ima bec ause t he t w o may appear similar (322). Alt hough hy perdensit y of t he aort ic w all at mult iple lev els has been report ed t o be spec if ic f or ac ut e aort ic dissec t ion (118), 40% of pat ient s w it hout dissec t ion in one series demonst rat ed t his f inding on nonc ont rast sc ans (174). Nev ert heless, a hy perdense aort ic w all t ends t o be unif ormly t hic k t hroughout t he v essel c irc umf erenc e in pat ient s w it hout dissec t ion, w hereas hy perdense t hic kening usually is ec c ent ric in t he unc ommon f orm of dissec t ion t hat oc c urs w hen int ramural hemat oma dev elops w it hout int imal rupt ure (363).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2538

17 - Retroperitoneum

F igure 17- 25 Aort oc av al f ist ula. Cont rast - enhanc ed c omput ed t omography show s aort ic aneury sm (ar r ow s) w it h aort oc av al f ist ula (arrow head). K, kidney s.

When t he dissec t ion inv olv es t he abdominal aort a, t he aort ic branc h v essels and t he organs t hey supply should be c aref ully ev aluat ed f or possible isc hemia. T w o t y pes of branc h v essel obst ruc t ion hav e been desc ribed. St at ic obst ruc t ion oc c urs w hen t he int imal f lap int ersec t s or ent ers t he branc h v essel and is t reat ed w it h int rav asc ular st ent ing. Dy namic obst ruc t ion oc c urs w hen t he int imal f lap is pressed against t he branc h v essel ost ia like a c urt ain and is t reat ed w it h f enest rat ion (291,353). T he number of abdominal organs w it h diminished enhanc ement on c ont rast - enhanc ed CT A had a st rong c orrelat ion w it h post operat iv e deat h in one series of 48 pat ient s w it h ac ut e dissec t ion ext ending int o t he abdomen (336). Bot h CT A and MRA hav e a high sensit iv it y and spec if ic it y f or t he diagnosis of aort ic dissec t ion (302) (F igs. 17- 26, 17- 27, 17- 28). Bot h w ork w ell f or ev aluat ion of ext ent of disease. Branc h inv olv ement may be bet t er delineat ed w it h P.1175 MDCT CT A bec ause of it s improv ed spat ial resolut ion (356). In general, bec ause of it s c lose proximit y t o t he emergenc y depart ment and short examinat ion t ime, c ont rast - enhanc ed MDCT w it h mult iplanar rec onst ruc t ions has bec ome t he t est of c hoic e in t he ac ut e set t ing. In st able pat ient s w it h a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2539

17 - Retroperitoneum c ont raindic at ion t o iodinat ed c ont rast or in f ollow - up of c hronic dissec t ion, MRI is a good alt ernat iv e. T he diagnosis of an aort ic dissec t ion c an be made on unenhanc ed SE or GRE images (153,205). F low - relat ed signal v oid in bot h t he t rue and f alse lumen out lines t he t hin int imal f lap on unenhanc ed SE images. On oc c asion, int raluminal signal may appear in t he f alse c hannel bec ause of slow P.1176 blood f low or t hrombus (see F ig. 17- 28). As st at ed prev iously , slow f low c an be dif f erent iat ed f rom a t hrombus by c omparing t he signal int ensit y on t he

f irst and sec ond ec ho image. T hey also c an be dif f erent iat ed on f low - sensit iv e gradient ec ho or phase images (205). Nonenhanc ed t rue f ast imaging w it h st eady - st at e prec ession (F ISP) has also been used as a rapid (less t han 4 minut es) ev aluat ion f or aort ic dissec t ion w it h good suc c ess (245). T he use of c ont rast - enhanc ed 3D MRA prov ides a higher signal- t o- noise rat io and superior v isualizat ion t han nonc ont rast t ec hniques and has bec ome t he t ec hnique of c hoic e (113). In c ont radist inc t ion t o nonc ont rast imaging it also allow s ev aluat ion of organ perf usion. Imaging of t he ent ire aort a and it s branc hes c an be c omplet ed w it hin a breat h- hold. Cont rast - enhanc ed 3D MRA prov ides ac c urat e inf ormat ion regarding t he ent ry and re- ent ry sit es of t he dissec t ion, t he lengt h of t he int imal f lap, and t he pat enc y of branc h v essels (340).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2540

17 - Retroperitoneum

F igure 17- 26 Aort ic dissec t ion t y pe B. A: Comput ed t omography angiogram show s abdominal aort ic dissec t ion (ar r ow head). T he origin of t he c eliac art ery (ar r ow ) is f rom t he f alse lumen. L, liv er; S, spleen. B: Image at a low er lev el show s t he superior mesent eric art ery originat ing f rom t he t rue lumen. K, kidney . C : Right renal art ery originat es f rom t he t rue lumen. D: Lef t renal art ery originat es f rom f alse lumen. Not e reduc ed c ont rast enhanc ement of t he lef t kidney (LK) c ompared w it h t he right kidney (RK). P, panc reas. E: Coronal rec onst ruc t ion show s t y pe B aort ic dissec t ion (ar r ow s) ext ending f rom arc h t o bif urc at ion. LU, lungs. F : Sagit t al rec onst ruc t ion show s dissec t ion originat ing

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2541

17 - Retroperitoneum just dist al t o t he lef t subc lav ian art ery (arrow head) and ext ending int o t he abdominal aort a. Not e t he origin of t he superior mesent eric art ery f rom t he t rue lumen (ar r ow ).

F igure 17- 27 Aort ic dissec t ion. A: Coronal half F ourier snap shot t urbo spin ec ho magnet ic resonanc e (MR) image show s abdominal aort ic dissec t ion (ar r ow s). L, liv er.B: Coronal c ont rast - enhanc ed MRI show s dissec t ion in abdominal aort a (ar r ow s). L, liv er. C : Coronal post c ont rast maximum- int ensit y projec t ion MRI show s aort ic dissec t ion w it h origin of t he c eliac axis (ar r ow ) f rom t rue lumen and origin of lef t renal art ery (arrow head) f rom f alse lumen. A, aort a; K, kidney .

T he inabilit y of MRI t o c onsist ent ly demonst rat e small c alc if ic at ions is not of c linic al signif ic anc e in most pat ient s. How ev er, in t he rare c ase of c omplet e t hrombosis of t he f alse c hannel, t he det ec t ion of an int imal f lap by MRI may not be possible. In t hese pat ient s, ec c ent ric (or rarely c onc ent ric ) aort ic w all

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2542

17 - Retroperitoneum

t hic kening may be t he only sign of ac ut e dissec t ion (358). T he w all t hic kening may be inhomogeneous w it h hy perint ense f oc i and linear st reaks or, less c ommonly , may be homogeneously isoint ense w it h musc le on t he T 1- w eight ed images (358).

F igure 17- 28 Aort ic dissec t ion. A: T ransaxial gat ed T 1- w eight ed spin ec ho image (repet it ion t ime, 1,219 millisec onds; ec ho t ime, 25 millisec onds) show s an int imal f lap (ar r ow ). F low v oid in t he t rue lumen (T ) is a result of highv eloc it y f low , w hile signal in t he f alse lumen (F ) is a result of slow f low or t hrombosis. B: Post - gadolinium T 1- w eight ed f ast low - angle shot image (repet it ion t ime, 140 millisec onds; ec ho t ime, 4 millisec onds; f lip angle, 80 degrees) at t he same lev el show s enhanc ement of bot h lumens w it h bet t er delineat ion of t he int imal f lap. C : Image obt ained at t he lev el of t he superior mesent eric art ery t akeof f demonst rat es poor enhanc ement of t he lef t kidney bec ause of renal art ery inv olv ement .

P.1177

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2543

17 - Retroperitoneum Abdominal Aortic Aneurysm—Surgical and Endovascular Repair

Repair of an AAA c an be perf ormed w it h eit her a t radit ional open proc edure or w it h more rec ent ly int roduc ed endov asc ular t ec hniques. In t he f ormer met hod, perf ormed v ia eit her a t ransabdominal or ret roperit oneal inc ision, t he aneury sm sac is opened and a graf t is insert ed w it h it s proximal end sew n t o uninv olv ed aort a proximal t o t he aneury sm and it s dist al end eit her sew n t o uninv olv ed aort a (t ube graf t ) or t o uninv olv ed c ommon iliac or f emoral v essels (bilimbed graf t ). T he aneury sm sac is t hen c losed ov er t he graf t and ac t s as a prot ec t iv e shell t o dec rease t he inc idenc e of post operat iv e AEF s. Endov asc ular repair inv olv es t he plac ement of an expandable st ent ed graf t t hat bridges t he AAA eit her as a single- limbed or bif urc at ed graf t (F igs. 17- 29 and 17- 30). T he st ent is plac ed v ia a f emoral art ery art eriot omy and guided f luorosc opic ally int o posit ion (233). Alt hough t he f irst West ern report of a suc c essf ul repair of an AAA by endov asc ular approac h w as published in 1991 (242), result s hav e been promising and demonst rat e lit t le dif f erenc e in t he mort alit y rat es of endov asc ular repair and c onv ent ional surgery (1,200,217). Adv ant ages of endov asc ular repair inc lude short er hospit al and/or int ensiv e c are st ay , less blood loss, and f ew er sy st emic c omplic at ions (1,200). How ev er, endov asc ular repair c ost s more t han surgery and has a higher graf t f ailure rat e t han c onv ent ional surgery (200). Radiologic ev aluat ion of an AAA is import ant bef ore eit her open or endov asc ular repair. Prior t o open repair it is import ant t o not e t he size and ext ent of t he AAA, inv olv ement of t he iliac v essels, and relat ionship of major v asc ular branc hes (renal art eries, superior mesent eric art ery , c eliac art ery , inf erior mesent eric art ery ). T he presenc e of anomalous v enous st ruc t ures or horseshoe kidney should be not ed, as w ell as t he presenc e of inf lammat ory c hange about t he aort a. Conc omit ant int raabdominal pat hology , suc h as renal or c olonic t umors or gallst ones, should also be report ed (148). Caref ul pat ient selec t ion is also of c rit ic al import anc e f or a suc c essf ul endov asc ular aneury sm repair (F ig. 17- 31). Alt hough prec ise c rit eria w ill dif f er depending on t he dev ic e used, in general t here should be at least 1.5 t o 2 c m

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2544

17 - Retroperitoneum of normal c aliber aort a proximal t o t he AAA and dist al t o t he renal ost ia. T his “ nec k” should be c y lindric al in shape, P.1178

w it hout signif ic ant f laring and should be f ree of t hrombus. T he angle bet w een t he nec k and AAA should be less t han 60 degrees. If t he dist al “ landing” zone of t he endov asc ular graf t is in t he aort a, it needs t o be 2 t o 2.5 c m in lengt h, normal in c aliber, and f ree of t hrombus. In t he more c ommon sit uat ion, in w hic h a bilimbed graf t is used, t he iliac v essels must be of normal c aliber w it hout signif ic ant t ort uosit y . If ext ernal iliac v essels are used, t he int ernal iliac art eries must be embolized t o prev ent bac k f illing of t he aneury sm (233). T he c ommon and ext ernal iliac art eries must also be w ide enough t o ac c ommodat e t he deliv ery dev ic e, alt hough loc alized iliac st enosis is not it self a c ont raindic at ion t o endov asc ular repair sinc e angioplast y c an be perf ormed at t he t ime of t he proc edure. T he presenc e of aberrant or ac c essory renal v essels or a pat ent inf erior mesent eric art ery or lumbar art eries should be not ed. If t hey arise f rom t he aneury sm sac k, t hey may c ont ribut e t o a persist ent endoleak af t er t he proc edure or, if oc c luded by t he graf t , c ause dow nst ream isc hemia if suf f ic ient c ollat erals do not exist (233). Renal art ery st enosis also may c ont ribut e t o renal impairment and inc reases t he risk of t he proc edure. T he presenc e of perianeury smal f ibrosis or inf lammat ory c hange should also be not ed, alt hough it s role in pat ient selec t ion is c ont rov ersial (329).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2545

17 - Retroperitoneum

F igure 17- 29 Abdominal aort ic aneury sm t reat ed w it h endograf t repair. A: Cont rast - enhanc ed axial c omput ed t omography image of t he abdominal aort a (A) w it h aneury sm and at herosc lerot ic c hanges. B: 2 mont hs post –endograf t repair of abdominal aort ic aneury sm show s dec rease in sac (arrow head) size w it h endograf t (ar r ow s) in plac e. C : 8 mont hs post –endograf t repair of abdominal aort ic aneury sm show s f urt her dec rease in sac (ar r ow heads) size w it h endograf t (ar r ow s) in plac e.

In c onv ent ional surgic al repair, t he size of t he graf t is det ermined by direc t inspec t ion of t he v essels inv olv ed. In c ont radist inc t ion, endov asc ular graf t sizing is obt ained noninv asiv ely and t y pic ally inv olv es eit her CT A or, less c ommonly , MRA (225,319,348). Measurement s of diamet er are best t aken f rom planar images ort hogonal t o t he long axis of t he v essel and ref lec t t he dist anc e f rom w all t o w all rat her t han lumen edge t o lumen edge. Longit udinal measurement s are t y pic ally t aken f rom c urv ed planar rec onst ruc t ions along t he c ent erline of t he lumen. Commerc ially av ailable sof t w are using CT A or MRA sourc e dat a c an expedit e preoperat iv e planning. Some v ersions allow t he operat or t o plac e a 3D model of t he proposed endograf t w it hin a 3D represent at ion of t he pat ient 's aort a t o preoperat iv ely c hec k f it (348).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2546

17 - Retroperitoneum Surgically Placed Aortic Grafts: Postoperative Complications and Evaluation Aort ic graf t s are perf ormed f or replac ing aneury sms and by passing oc c lusiv e v asc ular disease. T heir imaging appearanc e depends on t he t y pe of anast omoses perf ormed and w het her t he graf t is laid w it hin t he sac of t he exist ing aneury sm (149).

F igure 17- 30 Abdominal aort ic aneury sm t reat ed w it h endograf t repair. A: Cont rast - enhanc ed axial c omput ed t omography sc an show s inf rarenal aort ic aneury sm w it h t hrombus (ar r ow s). B: 9 mont hs f ollow ing endograf t (ar r ow s) repair, t he aneury sm sac has shrunk slight ly in size. C : 16 mont hs f ollow ing endograf t repair, t here has been some f urt her reduc t ion in aneury sm sac size.

P.1179 Post operat iv e aort as c an be dist inguished f rom nat iv e at herosc lerot ic aort as bec ause t he graf t is of slight ly higher at t enuat ion t han unenhanc ed blood on

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2547

17 - Retroperitoneum nonc ont rast CT sc ans and it s lumen is perf ec t ly round and smoot h, w hereas t he pat ent lumen of an at herosc lerosic aort a is usually slight ly irregular. On

MRI, t he prost het ic graf t it self does not produc e any signal. In t he c ase of an end- t o- side anast omosis, t he graf t is seen v ent ral t o t he nat iv e aort a. T he iliac branc hes of t he graf t are seen as t w o dense c irc ular st ruc t ures ant erior t o t he c alc if ied nat iv e iliac art eries, w hic h are c ommonly t hrombosed. T he bif urc at ion of t he graf t is usually loc at ed 2 t o 3 c m c ephalad t o t he nat iv e aort ic bif urc at ion. T he CT appearanc e of end- t o- end anast omosis dif f ers f rom t hat of end- t oside anast omosis in it s c omplet e int errupt ion of t he nat iv e aort a at t he anast omot ic sit e. T heref ore, t he dist al nat iv e aort a is not opac if ied on post c ont rast sc ans. In pat ient s w ho hav e an end- t o- end anast omosis w it hin t he sac of an aneury sm (endoaneury smorrhaphy ), t he aneury sm sac is w rapped around t he graf t t o prov ide an addit ional lay er bet w een t he graf t and bow el t o reduc e t he risk of AEF f ormat ion. A c ollec t ion of serous f luid or sof t t issue at t enuat ion of t en c an be ident if ied bet w een t he sy nt het ic graf t and t he nat iv e aort ic w rap. T his c ollec t ion usually resolv es by 2 t o 4 mont hs (257). Similarly , perigraf t air may be seen in t he immediat e post operat iv e period (up t o 38% of pat ient s 6 t o 9 day s post surgery ) but usually resolv es by t hree w eeks (232,236,295). Larger aneury sms t y pic ally show ed more periprost het ic air (232). On MRI, a c ollec t ion of f luid bet w een t he aneury sm sac and graf t , w hic h show s relat iv ely low signal int ensit y on T 1- w eight ed images and high signal int ensit y on T 2- w eight ed images, is rout inely seen on MRI st udies obt ained w it hin sev eral w eeks of surgery and should be c onsidered abnormal if present af t er 3 mont hs (15). Af t er P.1180 7 t o 10 w eeks, a perigraf t c ollar of low signal int ensit y is of t en seen on T 1and T 2- w eight ed images and likely represent s f ibrosis or t he w all of t he nat iv e aort a adherent t o t he graf t (graf t inc orporat ion) (15).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2548

17 - Retroperitoneum

F igure 17- 31 Measurement s import ant f or endov asc ular aneury sm repair. Diamet er of : t he aneury sm nec k at t he low est renal art ery (a), of t he aort a 1.5 c m below t he renal art eries (b), of t he aneury sm sac (c ), of t he aort a 1.5 c m abov e t he bif urc at ion (d), of t he c ommon iliac art eries (e1, e2), of t he ext ernal iliac art eries (f 1, f 2). Lengt h of t he proximal aneury sm nec k (A), of t he abdominal aort ic aneury sm (AAA) (B), of t he dist al aneury sm nec k (C), of t he c ommon iliac art eries (D1, D2). Angle bet w een t he proximal nec k and t he AAA is also measured. (Adapt ed f rom T hurnher SA, Dorf f ner R, T hurnher MM, et al. Ev aluat ion of abdominal aort ic aneury sm f or st ent - graf t plac ement : c omparison of gadolinium- enhanc ed MR angiography v ersus helic al CT angiography and digit al subt rac t ion angiography . Radiology 1997;205:341–352.)

Post operat iv e c omplic at ions of abdominal aort ic graf t surgery inc lude hemorrhage and pseudoaneury sm f ormat ion, major v essel or graf t limb oc c lusion, inf ec t ion, and AEF (see F igs. 17- 23 and 17- 24). When ac ut e hemorrhage is suspec t ed, a nonc ont rast CT sc an is of t en helpf ul f or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2549

17 - Retroperitoneum ident if ic at ion of t he inc reased at t enuat ion of f resh blood. Pseudoaneury sms t y pic ally oc c ur at t he anast omot ic sut ure line and are more c ommon in t he f emoral area t han in t he aort oiliac sy st em (295). In one st udy of 69 pat ient s

w it h pseudoaneury sms, t he t ime bet w een graf t insert ion and pseudoaneury sm det ec t ion ranged f rom 1 t o 238 mont hs, w it h a median t ime of 92 mont hs (331). Anast omot ic pseudoaneury sms appear as paragraf t c ollec t ions c ont aining t hrombus. Port ions of t he pseudoaneury sm may c ommunic at e w it h t he aort ic lumen and enhanc e t o t he same degree on post c ont rast sc ans. In ot her pat ient s, t he ent ire pseudoaneury sm may be f illed w it h t hrombus and appear as a div ert ic ulum (101). T he diagnosis of graf t oc c lusion is based on t he demonst rat ion of a low - densit y lumen represent ing t hrombus, w it h a lac k of enhanc ement af t er administ rat ion of c ont rast medium. Graf t inf ec t ion is t he most serious c omplic at ion of abdominal aort ic graf t surgery , w it h a mort alit y rat e of 25% t o 88% (39). Alt hough diagnosis may be obv ious, part ic ularly if a f emoral anast omoses is inv olv ed, it is of t en more subt le if t he proximal aort ic limb only is inf ec t ed (39,236). T y pic ally , w hen a graf t bec omes inf ec t ed, an irregular c ollec t ion of f luid and sof t t issue at t enuat ion is seen around t he prost hesis, somet imes assoc iat ed w it h mult iple small bubbles of gas loc at ed post erior t o or around t he ent ire graf t (195) (see F igs. 17- 24). T his is in c ont radist inc t ion t o a “ normal” gas c ollec t ion seen in t he immediat e post operat iv e period, w hic h usually is solit ary and ant erior in loc at ion (103). Disc ont inuit y of t he env eloping aneury sm w rap and inc reased sof t t issue/f luid (great er t han 5 mm) bet w een t he w rap and graf t hav e also been c it ed as signs of inf ec t ion (195). Bec ause gas and sof t t issue/f luid may be a normal f inding in t he immediat e post operat iv e period, needle aspirat ion of a suspic ious perigraf t c ollec t ion is adv ised in any pat ient w it h suspec t ed inf ec t ion. Periprost het ic c ollec t ions bey ond t hree mont hs af t er surgery , and periprost het ic gas bey ond 4 t o 7 w eeks f rom surgery should be c onsidered highly suspic ious f or inf ec t ion (236). Alt hough t he ov erall sensit iv it y and spec if ic it y of CT f or inf ec t ion is high (195), nuc lear medic ine gallium sc anning and labeled leukoc y t e sc ans may also be of v alue (144,295). On MRI, perigraf t absc esses appear as f luid c ollec t ions t hat hav e low t o medium signal int ensit y (iso- or hy perint ense t o musc le) on T 1- w eight ed images and high int ensit y on T 2- w eight ed images (iso- or hy perint ense t o f at ) (146). Inf lammat ion in surrounding t issues, c harac t erized by a het erogeneous inc reased signal int ensit y of t he psoas musc les adjac ent t o t he graf t , also c an be seen (15). Gadolinium- enhanc ed T 1- w eight ed f at - suppressed imaging

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2550

17 - Retroperitoneum

ac c ent uat es t he c ont rast dif f erenc e bet w een nonenhanc ing low signal absc ess f luid and adjac ent enhanc ing inf lammat ory t issue. How ev er, t he inf ec t ed nat ure of t he f luid c annot be asc ert ained on t he basis of MR signal int ensit ies alone. A signif ic ant limit at ion of MRI is it s inabilit y t o det ec t small c ollec t ions of gas. In addit ion, MRI c annot reliably dif f erent iat e bet w een a c ollec t ion of gas and a small c lust er of c alc if ic at ions (146). Sec ondary AEF oc c urs bet w een an aort ic graf t and adjac ent bow el. CT f eat ures of sec ondary AEF are similar t o t hose of graf t inf ec t ion and inc lude perigraf t sof t t issue/f luid and ext raluminal air (195). Alt hough not spec if ic , t hic kening of t he small bow el, espec ially t he t hird port ion of t he duodenum, adjac ent t o paragraf t f luid, is highly suggest iv e of an AEF . Addit ional f indings, suc h as ext rav asat ion of oral c ont rast mat erial around t he graf t , int rav asat ion of int rav enous c ont rast mat erial int o unopac if ied small bow el, or small bow el hemat omas, are rare.

Endografts: Postoperative Complications and Evaluation Alt hough endov asc ular st ent ed graf t s c an be assoc iat ed w it h many of t he c omplic at ions of surgic ally plac ed graf t s, inc luding P.1181 inf ec t ion and rupt ure (243), t hey hav e unique problems t hat require long t erm f ollow - up and monit oring. T hese inc lude, most prominent ly , endoleaks, c ont inued aneury sm grow t h, endograf t oc c lusion, and displac ement or disrupt ion of t he st ent it self (233,348). Endov asc ular st ent ed graf t leaks (endoleaks) are div ided int o f our t y pes (348,349): T y pe 1 endoleak result s f rom an inc omplet e seal at t he proximal or dist al end of t he graf t and t he adjac ent nat iv e aort a or iliac w all (F ig. 17- 32). T y pe 2 endoleak oc c urs w hen blood f low s in a ret rograde f ashion int o t he aneury sm f rom pat ent aort ic branc h v essels (e.g., lumbar art eries, inf erior mesent eric art ery , ac c essory renal art eries) (F igs. 17- 33 and 17- 34). T y pe 3 endoleak leaks oc c ur f rom eit her a t ear in t he endograf t f abric or ot her st ent graf t st ruc t ural f ailure (F ig. 17- 35). T y pe 4 leaks are assoc iat ed w it h porous graf t mat erial.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2551

17 - Retroperitoneum

F igure 17- 32 T y pe 1 endograf t leak. A, B: Cont rast - enhanc ed c oronal c omput ed t omography images demonst rat e at t empt ed endograf t repair of an abdominal aort ic aneury sm w it h a t y pe 1 leak (ar r ow heads) originat ing at t he nec k of t he graf t (ar r ow ). Inf ilt rat ion of t he f at in t he lef t side of t he ret roperit oneum is sequela of rec ent iliac t o lef t renal art ery graf t (G).

CT is t he pref erred modalit y f or post operat iv e ev aluat ion of endograf t s (11,193,263) and may hav e a role in guiding perc ut aneous embolizat ion of some endoleaks. T he met allic st ent s are w ell v isualized and allow direc t ev aluat ion of st ent loc at ion and int egrit y . Int rav enous c ont rast enhanc ement is nec essary t o ev aluat e endoleaks. T hese appear as c ollec t ions of c ont rast w it hin t he aneury smal sac . Biphasic sc anning is suggest ed as some slow endoleaks are not apparent on t he init ial art erial phase images (92,281). Unenhanc ed sc anning prec eding t he enhanc ed sc ans has also been suggest ed t o be of benef it in dist inguishing c alc if ic at ion f rom c ont rast leakage (281). Reproduc ible ev aluat ion of aneury sm size is c ruc ial t o ensure adequat e exc lusion of t he aneury sm. Suc c essf ul endograf t plac ement w ill usually result in shrinkage of t he aneury sm sac alt hough t his may depend on t he t y pe of graf t employ ed (26,74). Any inc rease in aneury sm size is c ause f or c onc ern, bec ause progressiv e enlargement and rupt ure may oc c ur ev en in t he absenc e of demonst rable endoleak (323,350). T he mec hanism f or t his inc rease in aneury sm size is unc lear but appears t o result f rom inc reased pressure (t ermed endot ension) w it hin t he aneury sm (66,350). Int rav enous c ont rast –enhanc ed MRI has also been used suc c essf ully in t he ev aluat ion of endograf t s c onst ruc t ed w it h met als of low magnet ic susc ept ibilit y , suc h as nic kel–t it anium alloy s (nit inol) (76,133,193). St ainless st eel–based st ent s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2552

17 - Retroperitoneum c annot be adequat ely ev aluat ed by MRI bec ause of signif ic ant art if ac t (133,318). T he use of MRI is f av ored in pat ient s w it h impaired renal f unc t ion or allergy t o iodinat ed c ont rast and in y ounger pat ient s in w hom repeat ed examinat ions w it h ionizing radiat ion may be problemat ic (318).

INFERIOR VENA CAVA AND ITS TRIBUTARIES Normal Anatomy T he IVC is f ormed by t he c onf luenc e of t he t w o c ommon iliac v eins at t he lev el of t he f if t h lumbar v ert ebra. F rom t his point , it asc ends along t he v ert ebral c olumn t o t he P.1182 right of t he aort a t o t he lev el of t he diaphragm and ent ers t he c hest t erminat ing in t he right at rium. Alt hough it is in c lose proximit y t o t he lumbar v ert ebral bodies in it s most c audal posit ion, it assumes a more v ent ral posit ion at it s c ephalic end.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2553

17 - Retroperitoneum F igure 17- 33 T y pe 2 endograf t leaks. A: Cont rast - enhanc ed axial c omput ed

t omography show s t y pe 2 endograf t leak (ar r ow ) at sit e of ent ry of ac c essory lef t renal art ery (ar r ow head). B: T y pe 2 endograf t leak (ar r ow ) is also not ed at t he origin of t he inf erior mesent eric art ery (ar r ow head). C : T y pe 2 endograf t leak (ar r ow ). Inf erior mesent eric art ery (arrow head).

T he shape, w hic h may be round or f lat , and t he size of t he IVC v ary f rom pat ient t o pat ient and ev en in t he same pat ient at dif f erent lev els. Perf ormanc e of a Valsalv a maneuv er usually result s in more dist ension of t he IVC in normal subjec t s. In pat ient s undergoing CT f or abdominal t rauma, a f lat IVC at mult iple lev els may be a sign of hy pov olemia result ing f rom major hemorrhage (139,299). In some c ases, t he demonst rat ion of t he c ollapsed IVC may prec ede t he c linic al det ec t ion of shoc k (139). It is import ant t o not e t hat a f lat t ened IVC may also be seen in normot ensiv e pat ient s and may be relat ed t o respirat ory v ariat ion as w ell as f luid st at us. In a st udy of 500 pat ient s imaged f or nont raumat ic indic at ions, a f lat IVC w as not ed at one or more lev el in 70 pat ient s. Of t hese pat ient s, only 30% had ev idenc e of hy pot ension or hy pov olemia (69). T he renal v eins, w hic h are loc at ed v ent ral t o t he renal art eries, of t en c an be seen in t heir ent iret y ent ering t he v ena c av a. T he lef t renal v ein usually is longer t han t he right and passes ac ross t he midline bet w een t he abdominal aort a and t he superior mesent eric art ery . T he main hepat ic v eins and t heir t ribut aries c onv erge int o t he v ena c av a near t he diaphragm. A small, ov al c ollec t ion of f at t hat lies medial t o t he IVC at or abov e t he lev el of c onf luenc e of t he hepat ic v eins and t he IVC may be seen in approximat ely 0.5% of pat ient s (214). It may oc c asionally mimic an int rav asc ular lipoma or c lot (123,262,285). T his c ollec t ion is c ont iguous w it h t he f at around t he subdiaphragmat ic port ion of t he esophagus, and it s presenc e or absenc e is not relat ed t o obesit y (214).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2554

17 - Retroperitoneum

F igure 17- 34 T y pe 2 endograf t leak. A: Nonc ont rast axial c omput ed t omography (CT ) image obt ained 1 mont h f ollow ing endograf t (ar r ow s) repair of an abdominal aort ic aneury sm. S, spine. B: Cont rast - enhanc ed axial CT image obt ained one mont h f ollow ing endograf t repair show s small leak (arrow head) near origin of t he inf erior mesent eric art ery t hat is c onsist ent w it h a t y pe 2 bac kf low leak.

P.1183 T he IVC, t he iliac v eins, and t he renal v eins c an be easily seen ev en on nonc ont rast CT sc ans. T he main hepat ic v eins and t heir t ribut aries also c an be seen on nonc ont rast sc ans bec ause t hey hav e a slight ly low er at t enuat ion t han t he normal hepat ic parenc hy ma. At least a port ion of normal c aliber gonadal v ein c an be t rac ed on c onsec ut iv e c ont rast - enhanc ed sc ans in a majorit y of pat ient s. Whereas t he right gonadal v ein drains direc t ly int o t he IVC, approximat ely 4 c m below t he junc t ion of t he right renal v ein and t he IVC (269), t he lef t gonadal v ein usually P.1184 drains int o t he lef t renal v ein. Below t he lef t renal v ein, t he lef t gonadal v ein is of t en seen post erior t o t he inf erior mesent eric v ein and ant erior t o t he lef t psoas musc le. T he gonadal v eins may be enlarged in mult iparous w omen and in men w it h v aric oc eles.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2555

17 - Retroperitoneum

F igure 17- 35 T y pe 3 endograf t leak. A: Cont rast - enhanc ed c oronal maximumint ensit y projec t ion c omput ed t omography image show s inf rarenal aort ic aneury sm (ar r ow heads). B: 1 mont h post –endograf t plac ement , a t y pe 3 leak is seen (arrow head). Ar r ow s, endograf t . C : 4 mont hs af t er endograf t plac ement t here has been resolut ion of t he prev iously not ed leak in t he sac . T he endograf t (ar r ow s) remains in plac e.

T he at t enuat ion v alue of t he lumen of t he IVC is similar t o t hat of t he abdominal aort a and t hus v aries w it h t he hemat oc rit of t he pat ient . How ev er, in c omparison t o t he aort ic w all, t he w all of t he IVC is t hin and rarely v isible as a disc ret e st ruc t ure, ev en in sev erely anemic pat ient s. T he IVC and it s t ribut aries are also w ell delineat ed by MRI bec ause of t he exc ellent c ont rast bet w een v asc ular st ruc t ures w it h f low ing blood and adjac ent sof t t issue. T he normal IVC demonst rat es no int raluminal signal on SE images but appears as a high signal int ensit y st ruc t ure on GRE sequenc es. As in t he aort a, a f low - relat ed enhanc ement ef f ec t (also c alled slic e- ent ry phenomenon) c an produc e a signal in t he IVC w hen t ransv erse SE images are obt ained. Unlike t he aort a, t he f low - relat ed signal is observ ed on t he most c audal slic e of t he imaged v olume bec ause of t he opposit e direc t ion of t he f low of blood.

Normal Variations (Congenital Anomalies) Know ledge of t he v arious dev elopment al anomalies of t he v enous sy st em and rec ognit ion of t heir CT /MRI appearanc es are c rit ic al f or proper image int erpret at ion and pat ient management . Venous anomalies may be mist aken f or adenopat hy or ot her pat hology . Azy gus c ont inuat ion of t he IVC may mimic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2556

17 - Retroperitoneum aort ic dissec t ion (203). Preoperat iv e ident if ic at ion of a v enous anomaly may prev ent iat rogenic injury part ic ularly w it h abdominal aort ic surgery (294). An

assoc iat ion of IVC anomalies w it h ot her anomalies (e.g., asplenia, poly splenia, renal aplasia) as w ell as w it h deep v enous t hrombosis has also been not ed (8,20,47,88,89,230). T he IVC is f ormed by t he suc c essiv e dev elopment and regression of t hree paired v eins, t he post erior c ardinal, subc ardinal, and suprac ardinal sy st ems (23,81,207,213) (F ig. 17- 36). T he post erior c ardinal sy st em dev elops f irst at approximat ely six w eeks but regresses w it hout f orming any of t he normal IVC, alt hough f ailure of c omplet e regression of t his segment is f elt t o be responsible f or ret roc av al uret er. T he right subc ardinal sy st em, dev eloping at 7 w eeks, f orms t he IVC c ephalad t o t he renal v eins and anast omoses w it h t he dev eloping hepat ic v essels t o f orm t he int rahepat ic IVC. Anast omosis of t he right and lef t subc ardinal sy st ems f orms t he normal lef t renal v ein. T he remainder of t he subc ardinal sy st em regresses. T he right suprac ardinal sy st em, dev eloping at approximat ely 8 w eeks, f orms t he azy gus sy st em c ephalad t o t he renal v eins and t he IVC c audal t o t he renal v eins. T he lef t suprac ardinal sy st em giv es rise t o t he hemiazy gus sy st em c ephalad t o t he renal v eins and normally regresses c audal t o t he renal v ein. Abnormal or absent regression of any of t hese v enous st ruc t ures result s in dif f erent anomalies. F or example, inf rahepat ic int errupt ion of t he IVC w it h azy gus c ont inuat ion oc c urs w it h f ailure of union of t he right subc ardinal sy st em w it h t he dev eloping hepat ic v eins. Duplic at ion of t he IVC result s f rom inc omplet e regression of t he lef t suprac ardinal sy st em. Sc hemat ic represent at ions of t hese v arious anomalies are show n in F igure 17- 37. Most of t hese v enous anomalies c an be c onf ident ly diagnosed on nonc ont rast CT or MRI sc ans by t rac ing t heir c ourse on c ont iguous slic es. If c onf usion persist s, t he v asc ular nat ure of t hese st ruc t ures c an be prov en by int rav enous c ont rast mat erial administ rat ion. Whereas c ont iguous t ransv erse CT or MR images are adequat e f or def ining t he anomalous v enous anat omy , t he ent ire sy st em c an be display ed more elegant ly by 3D rec onst ruc t ions of CT A or MRA dat a.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2557

17 - Retroperitoneum

F igure 17- 36 Sc hemat ic draw ing show ing t he prec ursors of dif f erent segment s of t he inf erior v ena c av a.

Interrupted Inferior Vena Cava with Azygos/Hemiazygos Continuation When t he right subc ardinal v ein f ails t o c onnec t w it h t he hepat ic v eins, blood ret urns t o t he heart t hrough t he azy gos/ hemiazy gos sy st em and t he hepat ic v eins drain direc t ly int o t he right at rium (F ig. 17- 38). Rare v ariat ions inc lude port al and hemiazy gos c ont inuat ion of t he IVC (81) and hemiazy gos c ont inuat ion of a lef t IVC (32,223). T his anomaly is seen w it h a prev alenc e of 0.6% and usually oc c urs as an isolat ed lesion (23). Oc c asionally , it c an be assoc iat ed w it h c ardiac abnormalit ies, or ot her v isc eral anomalies suc h as t he poly splenia sy ndromes (8,87).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2558

17 - Retroperitoneum

F igure 17- 37 Draw ings show ing relat ionships of aort a, inf erior v ena c av a, and lef t renal v ein in v arious c ongenit al v enous anomalies. (Adapt ed f rom Roy al SA, Callen PW. CT ev aluat ion of anomalies of t he inf erior v ena c av a and lef t renal v ein. J Com put Assist T om ogr 1979;15:690–693.)

P.1185 P.1186 On t ransv erse CT or MRI st udy , a normal IVC is seen f rom t he c onf luenc e of t he c ommon iliac v eins t o t he lev el of bot h kidney s. An int rahepat ic segment of t he IVC, w hic h lies ant erior t o t he right diaphragmat ic c rus and post erior t o t he c audat e lobe of t he liv er, is absent . How ev er, an enlarged azy gos v ein and of t en a hemiazy gos v ein as w ell c an be seen in t he ret roc rural spac e on bot h sides of t he aort a. T he azy gos v ein c an be f urt her t rac ed on more c ephalic sc ans t o t he lev el w here it arc hes ant eriorly t o join t he superior v ena c av a just below t he lev el of t he aort ic arc h.

Circumaortic Left Renal Vein T here is a t rue v asc ular ring about t he aort a in t his anomaly . T he preaort ic lef t renal v ein c rosses f rom t he lef t kidney t o t he IVC at t he expec t ed lev el of t he renal v eins. T he addit ional ret roaort ic lef t renal v ein(s) c onnec t s t o t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2559

17 - Retroperitoneum IVC by desc ending c audally and c rossing t he spine behind t he aort a, usually one t o t w o v ert ebrae below t he lev el of t he preaort ic lef t renal v ein (F ig. 1739). T y pic ally , t he lef t gonadal v ein drains int o t he aberrant ret roaort ic renal v ein. T his ret roaort ic renal v ein is f elt t o represent a remnant of t he lef t

suprac ardinal sy st em and int rasuprac ardinal anast omosis and has a prev alenc e of 1.6% (3). On a CT or an MRI st udy , a normal, albeit somew hat diminut iv e, lef t renal v ein c an be seen in it s preaort ic posit ion. T he anomalous ret roaort ic lef t renal v ein is ident if ied in a more c audal posit ion.

Retroaortic Left Renal Vein In t his anomaly , t he ant erior subc ardinal v eins regress c omplet ely and only t he ret roaort ic lef t suprac ardinal v ein and it s anast omoses w it h t he right suprac ardinal v ein remain t o drain t he lef t kidney . T he ret roaort ic lef t renal v ein c an be seen eit her at t he same lev el as a normal lef t renal v ein or in a more c audal posit ion, somet imes as low as t he c onf luenc e of iliac v eins (F ig. 17- 40). T he prev alenc e of t his anomaly is about 3% (3).

Left Inferior Vena Cava Anomalous regression of t he right suprac ardinal v ein and persist enc e of t he lef t suprac ardinal sy st em result in t ransposit ion of t he IVC. In t his ent it y , a single IVC asc ends on P.1187 P.1188 t he lef t side of t he spine and c rosses eit her ant erior or post erior t o t he aort a at t he lev el of t he renal v eins t o asc end f urt her t o t he right at rium on t he right side of t he spine. T he c harac t erist ic appearanc e on CT or t ransv erse MRI examinat ion is a single IVC t o t he right of t he aort a at lev els abov e t he renal v ein, a v asc ular st ruc t ure eit her c rossing ant erior or post erior t o t he aort a at t he lev el of t he renal v eins, and a large single IVC t o t he lef t of t he spine at lev els below t he renal v eins (F ig. 17- 41). T he prev alenc e of t his anomaly is 0.2% (3).

Duplication of the Inferior Vena Cava In duplic at ion of t he IVC, t here is an IVC, albeit smaller t han usual in size, along t he right side of t he spine. In addit ion, a lef t - sided IVC asc ends t o t he lev el of t he renal v eins t o join t he right - sided IVC t hrough a v asc ular st ruc t ure t hat may pass eit her ant erior or post erior t o t he aort a at t he lev el

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2560

17 - Retroperitoneum of t he renal v eins. Eit her v ena c av a c an be t he predominant v essel or t hey c an be of equal size. T his anomaly result s f rom t he persist enc e of bot h surprac ardinal v eins and has a prev alenc e of 0.4% (3). On a CT or an MRI st udy , a single right - sided IVC is seen at lev els abov e t he renal v eins. A

v asc ular st ruc t ure c rossing eit her ant erior or post erior t o t he aort a is seen at t he lev el of t he renal v eins, and t w o v ena c av ae, one on eac h side of t he aort a, are present below t he lev el of t he renal v eins (F ig. 17- 42). A duplic at ed lef t IVC c an be dif f erent iat ed f rom a dilat ed lef t gonadal v ein by f ollow ing it s c ourse on t he more c audad sc ans. Whereas a duplic at ed lef t IVC joins t he c ommon iliac v ein, a dilat ed lef t gonadal v ein c an be t rac ed f urt her inf eriorly t o t he lev el of t he inguinal c anal.

Circumcaval Ureter (Synonym, Retrocaval Ureter) Embry ologic ally , a c irc umc av al uret er result s f rom anomalous regression of t he c audal segment of t he right suprac ardinal v ein and t he persist enc e of t he right post erior c ardinal v ein. Consequent ly , t he uret er passes behind and around t he medial aspec t of t he IVC as it c ourses t o t he bladder. Alt hough more c ommonly desc ribed on t he right , a lef t ret roc av al uret er assoc iat ed w it h a lef t IVC also has P.1189 P.1190 been desc ribed (247). As in ot her t y pes of v ena c av al anomalies, c irc umc av al uret er may be disc ov ered as an inc ident al radiographic f inding. How ev er, pat ient s w it h t his c ondit ion somet imes present w it h signs and sy mpt oms relat ed t o right uret eral obst ruc t ion. Whereas asy mpt omat ic pat ient s or pat ient s w it h minimal c aliec t asis require only oc c asional f ollow - up, pat ient s w it h signif ic ant renal obst ruc t ion of t en require surgic al c orrec t ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2561

17 - Retroperitoneum

F igure 17- 38 Azy gus c ont inuat ion of t he inf erior v ena c av a (IVC). A: Cont rast - enhanc ed c omput ed t omography sc an show s prominent azy gus arc h (Az) empt y ing int o superior v ena c av a (S). A, aort a; E, esophagus. B: At t he lev el of t he diaphragm, hepat ic v eins empt y direc t ly int o t he right at rium. Azy gus v ein is prominent . A, aort a; Az, azy gus v ein; E, esophagus. C : At lev el of port a v ein (arrow head), no int rahepat ic IVC is present . Azy gus v ein (Az) is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2562

17 - Retroperitoneum prominent . L, liv er; S, spleen; K, kidney ; ar r ow , adrenals. D: At t he lev el of t he renal v eins (ar r ow s), t he azy gus bec omes t he IVC (I- Az). K, kidney . E: A normal inf rarenal IVC (I) is present . A, aort a; K, kidney .

F igure 17- 39 Circ umaort ic lef t renal v ein. A: Cont rast - enhanc ed c omput ed t omography sc an show s ant erior port ion of lef t renal v ein (ar r ow ) passing bet w een t he superior mesent eric art ery (ar r ow head) and aort a (A). I, inf erior v ena c av a. B: T he lef t renal v ein div ides int o ant erior and post erior branc hes (ar r ow heads). C : Ret roaort ic c omponent of lef t renal v ein is seen running post erior t o aort a (A) t o empt y int o inf erior v ena c av a (I).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2563

17 - Retroperitoneum

F igure 17- 40 Ret roaort ic lef t renal v ein. A, B: Cont rast - enhanc ed c omput ed t omography sc an show s ret roaort ic lef t renal v ein (ar r ow s) ext ending behind t he aort a (A) and empt y ing int o t he inf erior v ena c av a (I).

F igure 17- 41 Lef t - sided inf erior v ena c av a (IVC).A: Cont rast - enhanc ed c omput ed t omography sc an show s suprarenal IVC (I) in t he normal loc at ion. A, aort a; L, liv er; S, spleen. B: IVC (I) c rosses t o lef t v ia lef t renal v ein. C : IVC (I) remains t o lef t of aort a (A). No normally posit ioned IVC is seen on t he right .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2564

17 - Retroperitoneum

F igure 17- 42 Duplic at ed inf erior v ena c av a (IVC). A: Cont rast - enhanc ed c omput ed t omography sc an show s normal suprarenal IVC (I). A, aort a; L, liv er; S, spleen. B: Lef t - sided IVC drains int o lef t renal v ein (ar r ow ). C : Inf rarenal IVC is duplic at ed. Ar r ow , right IVC; ar r ow head, lef t IVC.D: At lev el of aort ic bif urc at ion, right (ar r ow ) and lef t IVC (arrow head) bec ome t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2565

17 - Retroperitoneum

c ommon iliac v eins. E: Lef t and right c ommon iliac v eins (ar r ow s) and art eries (ar r ow heads).

F igure 17- 43 Circ umc av al uret er. A: Post c ont rast c omput ed t omography image demonst rat es a dilat ed proximal right uret er (ar r ow ). B: At 1 c m c audal t o (A), t he right uret er (ar r ow ) passes behind t he inf erior v ena c av a (c ). C : At 1 c m c audal t o (B), t he right uret er (ar r ow ) lies ant erior t o t he inf erior v ena c av a (c ). T his is in c ont rast t o t he normal lef t uret er (arrow head), w hic h lies along t he ant erolat eral aspec t of t he psoas musc le.

Circ umc av al uret er has a c harac t erist ic appearanc e on exc ret ory urography (medial dev iat ion of t he upper one t hird of t he uret er w it h sharp t urn t ow ard t he pedic le of t he t hird or f ourt h lumbar v ert ebra produc ing a “ rev erse J” c onf igurat ion). How ev er, a def init iv e diagnosis by c onv ent ional imaging met hods of t en requires c onc omit ant opac if ic at ion of t he uret er and IVC. CT c an simplif y t he diagnost ic proc ess. Wit h CT , t he proximal right uret er c an be seen c oursing medially behind and t hen ant eriorly around t he IVC so as t o enc irc le it part ially (F ig. 17- 43). T hree- dimensional rendering of images t aken in t he exc ret ory phase has been report ed t o show t he abnormalit y c learly (246).

Other Rare Anomalies

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2566

17 - Retroperitoneum Ot her rare IVC anomalies hav e also been report ed, inc luding c ongenit al

port ac av al shunt s (18), absenc e of t he inf rarenal IVC w it h preserv at ion of t he suprarenal segment (22), and c ombinat ions of prev iously desc ribed anomalies, suc h as duplic at ed IVC w it h azy gus c ont inuat ion (213).

INFERIOR VENA CAVA—PATHOLOGIC CONDITIONS Aneurysm of the Inferior Vena Cava IVC aneury sms are quit e rare and c an be c lassif ied as c ongenit al (e.g., f ailure of regression or abnormal f usion of embry ologic v enous st ruc t ures) or ac quired (sec ondary t o t rauma, inf lammat ion, inc reased f low , or pressure). T y pic ally , t hese are t rue aneury sms c ont aining all t hree lay ers of t he normal w all, alt hough t he elast ic and musc ular lay ers may be at t enuat ed (41). T he lesions may be asy mpt omat ic or present w it h sy mpt oms sec ondary t o t hrombosis, obst ruc t ion, or embolism (192,309). T he aneury sm may also mimic a solid t umor in appearanc e. On c ont rast - enhanc ed CT or MRI, t he aneury sm appears as a sac c ular or f usif orm dilat ion of t he IVC (F ig. 17- 44) (292,367). Cont rast enhanc ement may demonst rat e t he v asc ular nat ure of t he lesion; how ev er, mixing phenomenon or t hrombosis may c ause t he lesion t o mimic a solid P.1191 neoplasm (59). T he “ lay ered gadolinium” sign of normal hy perint enseenhanc ed blood sit t ing on t op of a dark hy point ense lay er in t he aneury sm has been desc ribed as a sign of an abdominal v enous aneury sm (168).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2567

17 - Retroperitoneum

F igure 17- 44 Inf erior v ena c av a (IVC) aneury sm. A: Coronal rec onst ruc t ion of int rav enous c ont rast - enhanc ed c omput ed t omography sc an show s rounded st ruc t ure w it h het erogeneous enhanc ement (ar r ow heads) c oming of f t he right side of t he IVC (ar r ow ). Not e ext ensiv e t hrombosis w it hin IVC. A, aort a; L, liv er B: Axial image demonst rat es IVC aneury sm (ar r ow heads), w it h mixing of c ont rast and unopac if ied blood. A, aort a; L, liv er; K, kidney ; ar r ow aort a.

Venous Thrombosis T hrombosis in t he IVC and ot her ret roperit oneal v eins may result f rom a v ariet y of disorders. Surgic al t rauma, inf lammat ion, obst ruc t ion t o out f low by ret roperit oneal adenopat hy or int rav asc ular membrane, ext ension of t hrombus f rom iliac or renal v eins, and hy perc oagulable st at es hav e all been report ed t o induc e t hrombosis (F igs. 17- 45 and 17- 46) (24). Similarly , int rav asc ular t umor t hrombus has been report ed w it h a v ariet y of neoplasms, inc luding renal c ell, t ransit ional c ell, adrenal c ort ic al, and hepat oc ellular c arc inoma, leiomy osarc oma, and malignant f ibrohist ioc y t oma (F igs. 17- 47, 17- 48, 17- 49) (48,72,147,215).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2568

17 - Retroperitoneum

F igure 17- 45 Post part um sept ic t hrombosis of t he lef t ov arian v ein. Sequent ial post c ont rast c omput ed t omography images demonst rat e a t hrombosed lef t ov arian v ein (ar r ow ) and it s surrounding inf lammat ory c hanges (ar r ow heads) Open ar r ow , lef t uret er.

F igure 17- 46 T hrombosis of mult iple v essels in a pat ient w it h ov arian c anc er: c omput ed t omography (CT ) appearanc e. Cont rast - enhanc ed CT sc an show s int raluminal hy podense f illing def ec t s represent ing t hrombi w it hin t he opac if ied

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2569

17 - Retroperitoneum lumens of t he lef t renal v ein (ar r ow ) (A), lef t gonadal v eins (ar r ow s) (B:), and right gonadal v ein (sm all ar r ow ) and IVC (lar ge ar r ow )(c ).

P.1192 T he def init iv e diagnosis of v enous t hrombosis using CT depends on demonst rat ion of an int raluminal t hrombus (F ig. 17- 50). Whereas a f resh t hrombus has a densit y similar t o or higher t han t hat of c irc ulat ing blood, an old t hrombus is of low er densit y t han t he surrounding blood on nonc ont rast sc ans. In ac ut e t hrombosis, t he v essel may appear larger t han normal. T his inc reased size is usually more f oc al t han t he generalized dilat at ion seen sec ondary t o inc reased blood f low or inc reased v asc ular resist anc e at t he lev el of t he diaphragm/right at rium. How ev er, in t he c ase of c hronic oc c lusion, t he IVC may bec ome at rophic and c alc if ied. F ollow ing c ont rast administ rat ion, t he t hrombus w ill appear as eit her a low - densit y f illing def ec t surrounded by c ont rast - enhanc ed blood, in t he c ase of part ial obst ruc t ion, or as a low densit y mass obst ruc t ing t he lumen. In ac ut e t hrombosis inc reased t hic kness and enhanc ement of t he v essel w all may also be observ ed. Caut ion must be t aken not t o c onf use t rue int raluminal def ec t s w it h t hose c aused by t he laminar f low phenomenon in t he dy namic st age of c ont rast administ rat ion. In t his nonequilibrium phase, slow er f low ing enhanc ed blood may st ay c losest t o t he v essel w all, w it h unopac if ied blood f low ing c ent rally , suggest ing a luminal t hrombus. T his “ pseudot hrombus” art if ac t is most not ic eable in t he suprarenal c av a, w here it is c aused by poor mixing bet w een t he densely opac if ied renal v enous ef f luent and t he less densely opac if ied inf rarenal c av al blood (F ig. 17- 51). T his art if ac t c an be dif f erent iat ed f rom a t rue t hrombus by it s unsharp border, and t he high at t enuat ion of t he pseudot hrombus. T he use of delay ed equilibrium sc ans, in w hic h adequat e t ime has passed f or homogeneous v enous opac if ic at ion, is rec ommended w hen v enous t hrombosis is suspec t ed. Suc h delay ed sc ans (beginning 3 minut es af t er t he st art of c ont rast administ rat ion) looking f or t he IVC and more proximal t hrombus hav e been suggest ed as a usef ul adjunc t in pat ient s undergoing CT pulmonary angiography (194). In c ases of c omplet e c av al obst ruc t ion, ext ensiv e v enous c ollat erals may also be ident if ied by CT (237). T hese inc lude t he parav ert ebral v enous sy st em and it s c ommunic at ions w it h t he asc ending lumbar v eins and t he azy gos/hemiazy gos P.1193 sy st em; gonadal, periuret eric , and ot her ret roperit oneal v eins; abdominal w all v eins;hemorrhoidal v enous plexus; and t he port al v enous sy st em.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2570

17 - Retroperitoneum

F igure 17- 47 Renal c ell c arc inoma ext ending int o t he inf erior v ena c av a (IVC). A: T ransaxial post gadolinium T 1- w eight ed f ast low - angle shot image (repet it ion t ime, 140 millisec onds; ec ho t ime, 4 millisec onds; f lip angle, 80 degrees) show s a large nec rot ic right renal mass (M). A, aort a, I, IVC. B: Superiorly , enhanc ing t umor t hrombus (ar r ow ) is present w it hin t he dilat ed IVC. Coronal (C ) and sagit t al (D) images c learly demonst rat e t he c ephalic ext ent of t he t umor t hrombus (ar r ow ) w it hin t he inf rahepat ic IVC (I). L, liv er.

On nonc ont rast MRI SE T 1- w eight ed images, v enous t hrombus has a v ariable signal ranging f rom low t o high and is seen against t he signal v oid of f low ing blood. Alt hough slow f low may also produc e int raluminal signal, it c an be dif f erent iat ed f rom t hrombus by it s show ing an inc rease in signal int ensit y on t he sec ond ec ho image or by using a phase- sensit iv e imaging sequenc e (128,304). In c ont radist inc t ion t o SE images, v enous t hrombus appears as an area of low er signal on GRE images (13) and st ands out against t he bright signal of f low ing blood. A homogeneous appearanc e of t hrombus is seen w it h ac ut e t hrombus, w hile a het erogeneous pat t ern w it h hy point ense dot s w as seen in nonac ut e t hrombus (301). Bec ause GRE imaging t akes less t ime t han SE imaging, t he f ormer is t he pref erred nonc ont rast t ec hnique (304). MRA

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2571

17 - Retroperitoneum

based on t he GRE sequenc e is espec ially ef f ec t iv e in demonst rat ing t he ent ire v enous sy st em. How ev er, f alse–posit iv e diagnosis may oc c ur at t he c onf luenc e of v essels, w here t urbulent f low may reduc e t he signal of f low ing blood, simulat ing a t hrombus. Likew ise, subac ut e t hrombus, w hic h is of t en hy perint ense, may be c onf used w it h f low ing blood and lead t o a f alse–negat iv e diagnosis. In one st udy (13), a c ombinat ion of SE and GRE images signif ic ant ly inc reased t he ac c urac y of diagnosis of abdominal v enous t hrombosis. Alt ernat iv ely , t he pot ent ial problems w it h bot h nonc ont rast SE and GRE imaging c an be resolv ed by using int rav enous c ont rast (gadolinium c helat e).

F igure 17- 48 Leiomy osarc oma of t he inf erior v ena c av a (IVC). A: Cont rast enhanc ed c omput ed t omography sc an demonst rat es a large, het erogeneously enhanc ing, sof t t issue mass (M) abut t ing t he right kidney (K) and liv er (L). T umor markedly expands t he lumen of t he IVC and ext ends int o t he lef t renal v ein (ar r ow ). B, C : Superiorly , not e t he t hin rim of IVC w all enhanc ement (w hit e ar r ow s) and het erogeneous enhanc ement of t he t umor t hrombus (blac k ar r ow s). PV, port al v ein; open ar r ow s, unopac if ied hepat ic v ein radic les.

P.1194

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2572

17 - Retroperitoneum In c ases of c at het er- induc ed sept ic t hrombosis of t he IVC, gas bubbles hav e

been ident if ied w it hin t he t hrombi. In addit ion, inf lammat ory c hanges also c an be observ ed surrounding t he oc c luded v ein (218). T hrombosis of t he renal and gonadal v eins are also show n readily on CT and MRI. Bec ause t he right renal v ein is short er and more obliquely orient ed t han t he longer, more horizont al lef t renal v ein, direc t demonst rat ion of t hrombus is ac hiev ed less f requent ly on t he right t han on t he lef t . How ev er, t he use of t hinner sec t ions and t he new er MDCT sc anners improv e v isualizat ion of bot h renal v eins. T he inv olv ed segment of t he v ein c an be eit her normal in c aliber or subst ant ially enlarged. T hrombosis of ov arian v ein, c lassic ally assoc iat ed w it h post part um (puerperal) endomet rit is, pelv ic inf lammat ory disease, div ert ic ulit is, appendic it is, and gy nec ologic surgery (137,288), also c an oc c ur in pat ient s w it h malignant t umors, part ic ularly t hose undergoing c hemot herapy (136). Alt hough puerperal ov arian v ein t hrombosis is assoc iat ed w it h signif ic ant c omplic at ions, inc luding pulmonary embolism and uret eral obst ruc t ion, pat ient s w it h t hrombosis assoc iat ed w it h malignanc y and c hemot herapy are of t en asy mpt omat ic and t he need f or t herapy is unc ert ain (136). On CT , puerperal ov arian v ein t hrombosis appears as a w ell- def ined t ubular ret roperit oneal mass ext ending f rom t he pelv is t o t he inf rarenal IVC (see F ig. 17- 45). T he mass c orresponds t o t he dilat ed gonadal v ein and usually c ont ains a c ent ral low - at t enuat ion region, represent ing t hrombus (288). Ot her c ommon CT f indings inc lude an inhomogeneously enhanc ing pelv ic mass and f luid in an enlarged ut erus. Inf lammat ory c hanges also may be seen around t he oc c luded v ein. T umoral and nont umoral t hrombosis of t he IVC c an be ident if ied but not dif f erent iat ed f rom eac h ot her on CT sc ans unless hy perv asc ularit y is show n in t he t umoral t hrombus by c ont rast - enhanc ed CT (61). Expansion of t he v ein diamet er is also indic at iv e of t umor t hrombus (see F ig. 17- 48) (128). In some c ases of t umor t hrombus f rom renal c ell c arc inoma, hy perv asc ularit y is missing or dif f ic ult t o demonst rat e (369). Combined CT and P.1195 f luorodeoxy gluc ose posit ron emission t omography (F DG- PET ) sc anning has been rec ent ly report ed t o be usef ul in dist inguishing bland f rom t umor t hrombus, w it h t umor t hrombus show ing abnormal F DG upt ake (286). MRI may dist inguish some t umor t hrombus f rom bland t hrombus on t he basis of t heir signal c harac t erist ic s. High signal int ensit y on t he f irst and sec ond ec ho images is indic at iv e of a bland t hrombus. T hrombi of int ermediat e signal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2573

17 - Retroperitoneum int ensit y , how ev er, c an be seen in bot h bland and t umor t hrombi (128). Enhanc ement af t er int rav enous administ rat ion of gadolinium f av ors t umor

t hrombus as does isoint ensit y w it h t he primary neoplasm (see F ig. 17- 49). T he reliabilit y of MRI in dif f erent iat ing bet w een bland and t umor t hrombi is y et t o be det ermined in a large group of pat ient s.

F igure 17- 49 Leiomy osarc oma of t he inf erior v ena c av a (IVC). Coronal pregadolinium (A) and post gadolinium (B:) T 1- w eight ed f ast low - angle shot images (repet it ion t ime, 140 millisec onds; ec ho t ime, 4 millisec onds; f lip angle, 80 degrees) show a large ret roperit oneal mass (shor t ar r ow s) w it h peripheral enhanc ement . Cent ral hy point ensit y is a result of t issue nec rosis or c y st ic degenerat ion, c ommonly seen in leiomy osarc omas. Het erogeneously enhanc ing t umor ext ends int o a dilat ed IVC (long ar r ow ). L, liv er.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2574

17 - Retroperitoneum F igure 17- 50 T hrombus w it hin t he inf erior v ena c av a (IVC). Cont rast enhanc ed c omput ed t omography sc an show s a hy podense f illing def ec t w it hin t he opac if ied lumen of t he IVC (ar r ow ).

T ransv erse v iew s are of t en suf f ic ient f or t he diagnosis of c av al t hrombosis; how ev er, sagit t al and c oronal sec t ions f rom eit her MDCT or MRI more direc t ly display t he c ephaloc audal ext ent of t he t hrombus. T he lat t er inf ormat ion is part ic ularly import ant f or t he planning of resec t ion of t he t umor t hrombus. US is a w ell- est ablished t ec hnique f or ev aluat ing t he IVC. It c an det ec t c av al t hrombus f rom t he lev el of t he renal v eins t o t he right at rium in most pat ient s; how ev er, US has limit ed abilit y t o c learly demonst rat e t he rest of t he IVC bec ause of ov erly ing bow el gas (147). Alt hough gray sc ale sonography c annot dist inguish bland t hrombus f rom t umor t hrombus, c olor Doppler US has been report ed t o be able t o ident if y t he neov asc ularit y usef ul in making t his dist inc t ion (129).

Intracaval Filters Vena c av a f ilt ers are used in pat ient s w hen sy st emic ant ic oagulat ion is c ont raindic at ed or w hen rec urrent pulmonary emboli hav e oc c urred despit e sy st emic ant ic oagulat ion. F ree- f loat ing IVC or iliac t hrombus alone has also been c onsidered an indic at ion f or IVC f ilt ers. A v ariet y of dev ic es are av ailable f or perc ut aneous plac ement (158). CT has prov ed usef ul f or ev aluat ing t he posit ion of t he IVC P.1196 f ilt ers and t heir relat ion t o t he renal v eins. It is also helpf ul in rev ealing c omplic at ions inc luding malposit ion, f ilt er perf orat ion, ret roperit oneal hemat oma, and rec urrent t hrombosis and pulmonary emboli (210,268). F ilt er leg perf orat ions are a f airly c ommon oc c urrenc e but are usually asy mpt omat ic unless erosion int o adjac ent st ruc t ures suc h as t he duodenum or aort a oc c urs (143). MRI may also be used f or ev aluat ing pat ient s w it h c ert ain low - art if ac t c av al f ilt ers. In general, t it anium t ant alum and low iron–based alloy s c reat e less art if ac t t han t hose using st ainless st eel (313,314). SE and GRE images play c omplement ary roles in suc h an ev aluat ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2575

17 - Retroperitoneum

F igure 17- 51 Pseudot hrombus in t he inf erior v ena c av a (IVC). A: Comput ed t omography image at t he lev el of t he diaphragm obt ained 1 minut e af t er t he bolus int rav enous injec t ion of c ont rast mat erial int o an arm v ein show s a c ent ral hy podense def ec t w it hin t he IVC (ar r ow ). B: Repeat image at t he same lev el sev eral minut es lat er demonst rat es unif orm enhanc ement of t he IVC w it hout ev idenc e of a t hrombus.

Obliterative Hepatocavopathy (Synonym, Membranous Obstruction of the Inferior Vena Cava) Oblit erat iv e hepat oc av opat hy or membranous or segment al obst ruc t ion of t he IVC is a c ommon c ause of c hronic Budd- Chiari sy ndrome in Asia and Sout h Af ric a. T he pat hogenesis of t he disorder had been t hought t o be c ongenit al; how ev er, many now suggest t hat it is t he sequelae of prev ious bout s of IVC t hrombosis (234,235). In oblit erat iv e hepat oc av opat hy , t he hepat ic segment of t he IVC is obst ruc t ed by a f ibrous membrane or replac ed by c ordlike f ibrous t issue. In t he f ormer, t he IVC usually ends abrupt ly at a t hic k membrane. In t he lat t er, t he IVC show s a more c onic al appearanc e t apering t o an oblit erat ed or narrow ed segment ranging f rom 1 t o 17 c m in lengt h in one st udy (157). Calc if ic at ion is seen in t he oblit erat ed segment in 34% of c ases (157). Sonography has been most usef ul in t his disorder (188). Alt hough CT w ill also usually demonst rat e a narrow ed or oblit erat ed segment , simple axial images

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2576

17 - Retroperitoneum f requent ly miss membranous obst ruc t ion unless t he membrane is c alc if ied (162,188). In bot h sit uat ions (188), CT may show oblit erat ion of hepat ic v eins, sy st emic c ollat erals suc h as enlarged azy gos and subc ut aneous v eins, and ev idenc e of c irrhosis, port al hy pert ension, hepat ic neoplasm, or asc it es. T he liv er f requent ly demonst rat es hy pert rophy of t he c audat e and lef t lobe and at rophy of t he right lobe. Linear, irregular, ret ic ulat e or w edge- shaped areas of hy poat t enuat ion are not ed in t he periphery of t he liv er (157).

Iliocaval Compression Syndrome (Synonym, May-Thurner Syndrome) Compression and part ial obst ruc t ion of t he lef t c ommon iliac v ein by t he c rossing right c ommon iliac art ery may result in c hronic v enous st asis or deep v enous t hrombosis in t he lef t low er ext remit y . Alt hough t he diagnost ic f indings of ext ernal c ompression of t he iliac v ein, prest enot ic enlargement of t he proximal iliac v ein, and prominent v enous c ollat erals are most easily rec ognized using c ont rast v enography , t hey hav e also been desc ribed using CT (50).

Primary Inferior Vena Cava Neoplasm Leiomy osarc oma originat ing f rom t he w all of t he IVC is a rare ret roperit oneal neoplasm. It oc c urs more c ommonly in w omen t han men, w it h a mean age of 54 y ears in one large series (212). T y pic al present ing sy mpt oms inc lude abdominal pain, palpable mass, and low er limb edema. T umors are most f requent ly loc at ed in t he middle or low er sec t ion of t he IVC below t he hepat ic v eins (170,212). T y pic ally , t he t umors are large, av eraging 10 t o 11 c m in maximum diamet er (124,212). Alt hough an ext raluminal grow t h pat t ern is most c ommon, an int raluminal or dumbbell pat t ern (bot h int ra- and ext raluminal) is not inf requent (170,212). CT or MRI of t en show s a het erogeneously enhanc ing, w ell- c irc umsc ribed, lobulat ed right - sided ret roperit oneal mass inseparable f rom t he IVC, w it h displac ement of adjac ent organs suc h as t he right kidney , panc reas, duodenum, and aort a (see F igs. 17- 48 and 17- 49) (334). T he IVC P.1197 is usually dilat ed in c ases w it h primarily int raluminal grow t h. Calc if ic at ion is unc ommon (111). On MR images, leiomy osarc omas w it h ext raluminal ext ent

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2577

17 - Retroperitoneum hav e homogeneous hy point ensit y t o int ermediat e signal int ensit y on T 1w eight ed sequenc es and more het erogeneous int ermediat e t o high signal int ensit y on T 2- w eight ed sequenc es. Int raluminal t umor grow t h c an be dist inguished f rom blood t hrombus on MRI. Blood t hrombus has a signal int ensit y t hat is higher t han t hat of t umor on bot h T 1- and T 2- w eight ed

imaging (29,119). In upper IVC leiomy osarc omas, dif f erent iat ion f rom a primary right adrenal c arc inoma w it h v enous ext ension may be dif f ic ult .

LYMPH NODES Normal Anatomy In t he ret roperit oneum, ly mph nodes c an be f ound surrounding t he IVC and aort a (F ig. 17- 52). Ly mph nodes also c an be seen in t he root of t he mesent ery and along t he c ourse of t he major v enous st ruc t ures draining t o t he IVC and port al v ein. In t he pelv is, ly mph nodes c an be ident if ied in c lose proximit y t o t he iliac v essels. Alt hough less c ommonly seen, ly mph nodes also c an be f ound ant erior t o t he psoas musc le and adjac ent t o t he post erior iliac c rest (44,351). Normal ly mph nodes in t he abdomen and pelv is are rout inely seen on CT or MR sc ans as small, oblong, sof t t issue densit ies ranging f rom 3 t o 10 mm in size (99,337). Short axis measurement s should be used t o minimize errors result ing f rom node orient at ion. T he int ernal arc hit ec t ure of a ly mph node generally is not disc ernible on CT or MRI, and dist inguishing inf lammat ory adenopat hy f rom neoplast ic inf ilt rat ion is usually not possible. Normal nodes t y pic ally show lit t le enhanc ement w it h int rav enous c ont rast —a f ac t t hat is usef ul in dist inguishing small nodes f rom v asc ular st ruc t ures, part ic ularly in t he mesent ery and in t he pelv is. T he densit y of normal ly mph nodes is similar t o t hat of musc le on bot h c ont rast - enhanc ed and unenhanc ed CT sc ans. On MRI, t he signal int ensit y of ly mph nodes on T 1- w eight ed images is slight ly higher t han t hat of musc le and diaphragmat ic c rura and is muc h low er t han t he signal int ensit y of f at . On rare oc c asions, how ev er, ly mph nodes may be nearly isoint ense t o f at on T 1- w eight ed images bec ause of hemorrhage or melanin (F ig. 17- 53). On T 2- w eight ed images, t he signal int ensit y of nodes inc reases, and henc e, t he c ont rast bet w een ly mph nodes and musc le inc reases and t hat bet w een nodes and f at dec reases. T hus, on T 2- w eight ed images, ly mph nodes are easily dist inguished f rom musc le and diaphragmat ic c rura but may be

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2578

17 - Retroperitoneum dif f ic ult t o dif f erent iat e f rom surrounding ret roperit oneal f at bec ause of t heir similar signal int ensit y .

F igure 17- 52 A: Sc hemat ic draw ing denot ing dist ribut ion of periaort ic and peric av al ly mph nodes. B: Comput ed t omography image in a pat ient af t er ly mphangiography , show ing normal dist ribut ion of ret roperit oneal ly mph nodes (ar r ow heads). Ao, aort a; C, inf erior v ena c av a; K, kidney .

In general, MRI is c omparable t o CT in t he det ec t ion of ret roperit oneal ly mph nodes in adult s (99,179,365). CT is generally perf ormed w it h 5- mm sec t ions and int rav enous c ont rast . Wit h MRI, T 1- w eight ed images are most usef ul. F at suppression t ec hniques may aid v isualizat ion part ic ularly w it h T 2- w eight ed sequenc es or w it h gadolinium- enhanc ed T 1- w eight ed sequenc es, bec ause suppression of t he ret roperit oneal f at w ill render t he higher signal int ensit y ly mph nodes more c onspic uous. Ly mph nodes are also easily separat ed f rom blood v essels on eit her SE or GRE images w it hout t he use of int rav enous c ont rast medium or f ollow ing t he use of gadolinium. As a result , displac ement or enc asement of blood v essels by ly mphadenopat hy is w ell demonst rat ed by MRI. P.1198 In general, mult iplanar v iew s eit her direc t ly ac quired, as w it h MRI, or rec onst ruc t ed, as w it h CT , add lit t le t o t he det ec t ion of normal or enlarged nodes. Axial v iew s are generally pref erred and suf f ic ient .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2579

17 - Retroperitoneum

F igure 17- 53 Hemorrhagic adenopat hy in a pat ient w it h Kaw asaki disease. A: T ransaxial gat ed T 1- w eight ed spin ec ho image (repet it ion t ime, 729 millisec onds; ec ho t ime, 15 millisec onds) show s mult iple hy perint ense enlarged ret roc rural nodes (ar r ow s) ref lec t ing hemorrhagic c ont ent s. B: Maximumint ensit y projec t ion image of a magnet ic resonanc e angiogram (t hreedimensional f ast imaging w it h st eady - st at e prec ession; repet it ion t ime, 30 millisec onds; ec ho t ime, 7 millisec onds; f lip angle, 25 degrees) show s a f usif orm lef t renal art ery aneury sm (ar r ow ).

LYMPH NODES—PATHOLOGIC CONDITIONS Lymphadenopathy—General Considerations T he diagnosis of ret roperit oneal ly mphadenopat hy by CT or MRI is based on rec ognit ion of nodal enlargement , somet imes c onc omit ant w it h displac ement or obsc urat ion of normal st ruc t ures in adv anc ed disease (F igs. 17- 54, 17- 55, 1756). F or example, massiv e enlargement of ret roaort ic and ret roc av al nodes may c ause ant erior displac ement of t hese v essels. Exc ept in unusually lean or c ac het ic pat ient s, enlarged ly mph nodes generally are w ell prof iled by surrounding f at . Ret roc rural and port ahepat is nodes should not exc eed 6 mm, w hereas t he upper limit of normal f or gast rohepat ic ligament nodes is 8 mm (38,65). Ret roperit oneal, c eliac axis, mesent eric , and pelv ic nodes great er t han 10 mm in size are c onsidered abnormal, but mult iple, slight ly smaller (8 t o 10 mm) nodes in t hese regions should be v iew ed w it h suspic ion (65,99,337). T he present at ion of ly mphadenopat hy may v ary f rom (a) one or sev eral disc ret e enlarged ly mph nodes t o (b) a more c onglomerat e group of c ont iguous

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2580

17 - Retroperitoneum enlarged nodes similar in size t o t he aort a or IVC t o (c ) a large homogeneous mass, in w hic h indiv idual nodes are no longer rec ognizable, obsc uring t he

c ont ours of normal surrounding st ruc t ures. Ly mph node enlargement sec ondary t o v iral or granulomat ous disease c annot be dif f erent iat ed f rom ly mphoma or met ast ases based on imaging f indings alone, alt hough t he massiv e t y pe of c onglomerat ion is almost nev er seen w it h t he benign c ondit ions (F ig. 17- 57). Alt hough most nodes hav e sof t t issue densit y on CT , hy podense adenopat hy may be seen w it h bot h malignant and benign disease. T est ic ular neoplasms, part ic ularly t erat oc arc inoma and epidermoid c arc inoma of t he genit ourinary t rac t of t en hav e low - densit y ly mphadenopat hy (F ig. 17- 58). T his may oc c ur f ollow ing t herapy and represent areas of nec rosis or liquef ac t ion, or it may be present init ially and c orrespond t o epit helial- lined c y st ic areas (289). Low densit y nodes are rarely not ed in pat ient s w it h ly mphoma (252). My c obac t erium inf ec t ion (more c ommonly M. t uber c ulosis t han M. av ium int r ac ellular e) and hist oplasmosis may also be assoc iat ed w it h hy podense nodes (F ig. 17- 59) (258,259). Whipple disease c an demonst rat e low - densit y adenopat hy (F ig. 17- 60). In t his disease, t he at t enuat ion v alue of t he enlarged ly mph nodes of t en is quit e low , ranging f rom +10 HU t o 30 HU (186), and is most likely c aused by t he deposit ion of f at and f at t y ac ids in t he ly mph nodes. Ly mphangioleiomy omat osis has been assoc iat ed w it h low - at t enuat ion ret roperit oneal masses and ly mphadenopat hy (16,360). Enlarged, low - densit y ly mph nodes may also be seen in t he c av it ary ly mph node sy ndrome assoc iat ed w it h c eliac sprue. T his rare c omplic at ion has a poor prognosis and may be assoc iat ed w it h poorly c ont rolled and long- st anding disease (120,127). On CT , enlarged c av it ary mesent eric nodes w it h f at –f luid lev els hav e been report ed (120).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2581

17 - Retroperitoneum

F igure 17- 54 Burkit t ly mphoma pre- and post t herapy .A: Cont rast - enhanc ed axial c omput ed t omography at t he lev el of t he c eliac axis (ar r ow ) show s bulky ly mphadenopat hy (N). K, kidney .B: Bulky mesent eric ly mphadenopat hy (N). Ar r ow , paraaort ic ly mph node; ar r ow head, aort oc av al node; K, kidney ; D, duodenum. C : F ollow ing t reat ment , t here has been almost c omplet e resolut ion of t he bulky adenopat hy adjac ent t o t he c eliac axis (ar r ow ). K, kidney . D: Mesent eric , paraaort ic , and aort oc av al ly mphadenopat hy has also almost c omplet ely resolv ed.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2582

17 - Retroperitoneum F igure 17- 55 Prost at e c anc er met ast ases w it h lef t inf erior v ena c av a (IVC). A: Cont rast - enhanc ed axial c omput ed t omography image at lef t renal v ein lev el show s lef t IVC draining int o lef t renal v ein (ar r ow ). Mult iple mat t ed ret roperit oneal ly mph nodes (N) are seen in t his pat ient w it h ly mphoma. K, kidney ; L, liv er; G, gallbladder. B: IVC (ar r ow ) lies lef t of aort a (ar r ow head). Ly mph nodes (N) lif t ing aort a and IVC f rom t he spine. L, liv er; K, kidney ; G, gallbladder.

F igure 17- 56 Ext ensiv e adenopat hy result ing f rom met ast at ic prost at e adenoc arc inoma. A: T ransaxial T 1- w eight ed f ast low - angle shot (F LASH) image (repet it ion t ime, 140 millisec onds; ec ho t ime, 4 millisec onds; f lip angle, 80 degrees) show s lobulat ed c irc umaort ic (A) t issue enc asing t he renal art eries (ar r ow s). B: T ransaxial post gadolinium T 1- w eight ed F LASH image (repet it ion t ime, 140 millisec onds; ec ho t ime, 4 millisec onds; f lip angle, 80 degrees) show s signif ic ant nodal enhanc ement . Not e t he ant erior displac ement of t he aort a, a f eat ure c ommonly seen w it h ly mphadenopat hy but not in ret roperit oneal f ibrosis. C : T ransaxial post gadolinium, f at - sat urat ed prot on densit y –w eight ed, spin ec ho image (repet it ion t ime, 2,400 millisec onds; ec ho t ime, 15 millisec onds) show s t he inc reased sensit iv it y t o c ont rast enhanc ement using t his sequenc e. U, unc inat e proc ess.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2583

17 - Retroperitoneum P.1199 P.1200 Bot h benign and malignant ly mphadenopat hy may exhibit mild t o pronounc ed enhanc ement af t er int rav enous administ rat ion of iodinat ed c ont rast mat erial (F ig. 17- 61) (131,251,252). Cont rast enhanc ement may be homogeneous, inhomogeneous, or peripheral. Alt hough t he majorit y of ly mphomas show only mild t o moderat e enhanc ement (199,252), hy perenhanc ing adenopat hy has been report ed in a number of disorders inc luding met ast asis f rom renal c ell

(F ig. 17- 62) and bladder c arc inoma, c arc inoid, and Kaposi sarc oma (121,131), and in angioimmunoblast ic ly mphadenopat hy (199) and Cast leman disease (F ig. 17- 63) (150). Pronounc ed enhanc ement may also be seen oc c asionally in my c obac t erial inf ec t ion. T his is most c ommonly peripheral, alt hough homogeneous enhanc ement has also been not ed (251). Nodal c alc if ic at ion c an oc c ur in pat ient s af t er granulomat ous inf ec t ion. It is also assoc iat ed w it h a v ariet y of malignanc ies inc luding muc inous c arc inoma, sarc omas, and t reat ed (and rarely unt reat ed) ly mphomas (F ig. 17- 64) (9,169). Alt hough in v it r o st udy has show n t hat ly mph nodes c ont aining met ast ases hav e a signif ic ant ly longer T 2 t han normal and hy perplast ic nodes (345), in v iv o t issue c harac t erizat ion based on relaxat ion t imes or signal int ensit ies has not been possible (64,179). Enlarged ly mph nodes result ing f rom malignant disease c annot be reliably dist inguished P.1201 by CT or rout ine MRI f rom t hose result ing f rom benign proc esses. F urt hermore, ly mph nodes t hat are of normal size but are part ially or t ot ally replac ed w it h a neoplasm w ill not be ident if ied as abnormal by rout ine MRI or CT .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2584

17 - Retroperitoneum

F igure 17- 57 Sarc oidosis w it h adenopat hy (ar r ow heads) and splenomegaly (S). L, liv er; K, kidney ; ar r ow , aort a.

Bot h MRI and CT c an be used f or ev aluat ion of ly mphadenopat hy . MRI has sev eral adv ant ages ov er CT . One adv ant age is it s abilit y t o dist inguish v asc ular st ruc t ures f romsof t t issue st ruc t ures w it hout t he use of iodinat ed c ont rast mat erial. In part ic ular, mildly enlarged pelv ic ly mph nodes may be dif f ic ult t o det ec t by CT bec ause of t he great v ariabilit y in loc at ion, diamet er, and orient at ion of t he pelv ic art eries and v eins. T his is espec ially t rue in pat ient s in w hom adequat e opac if ic at ion of bot h t he art eries and v eins is not ac hiev ed bec ause of t ec hnic al reasons. Ev en w it h t he administ rat ion of int rav enous c ont rast mat erial, mildly enlarged pelv ic nodes st ill may be c onf used w it h pelv ic v essels bec ause bot h w ill enhanc e (131). In t hese inst anc es, pelv ic ly mphadenopat hy is more easily demonst rat ed by MRI. Venous anomalies, prominent gonadal v eins, and c ollat eral v essels all may mimic ret roperit oneal ly mphadenopat hy on nonc ont rast CT st udies, but are easily show n t o be v asc ular st ruc t ures by MRI. CT similarly has sev eral adv ant ages ov er MRI. Alt hough a surv ey MRI examinat ion of t he abdomen and pelv is c an be c omplet ed by T 1- w eight ed GRE sequenc e in less t han a minut e, a t horough MR examinat ion t hat c onsist s of bot h T 1- and T 2- w eight ed sequenc es st ill t akes more t ime t han a c omparable CT st udy . F urt hermore, CT is less expensiv e and is more av ailable t han MRI. Wit h opt imal opac if ic at ion of bow el loops, CT c an also more easily det ec t ly mphadenopat hy in pat ient s w ho hav e lit t le ret roperit oneal f at and in pat ient s in w hom t he ret roperit oneal t issue planes hav e been alt ered by surgery . Bec ause of t he poorer spat ial

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2585

17 - Retroperitoneum resolut ion of MRI, a c lust er of normal- size ly mph nodes c ould appear as a single enlarged node on t he MRI st udy . F inally , MRI is unable t o det ec t small

c alc if ic at ions in ly mph nodes, a limit at ion t hat is of great er signif ic anc e in t he ev aluat ion of t he mediast inum t han in t he ret roperit oneum and pelv is.

F igure 17- 58 Low - densit y ly mph nodes in a pat ient w it h met ast at ic seminoma. Cont rast - enhanc ed c omput ed t omography sc an show s hy podense adenopat hy surrounding t he aort a. Not e t he elev at ion of t he aort a (A), lat eral displac ement of t he inf erior v ena c av a (ar r ow ), and ant erior displac ement of t he lef t renal v ein (ar r ow head).

In most inst it ut ions, CT remains t he imaging proc edure of c hoic e f or sc reening t heret roperit oneum f or ev idenc e of ly mphadenopat hy . If t he CT f indings are equiv oc al, an MRI st udy c ould be perf ormed. MRI should be c onsidered as t he primary imaging t ec hnique in t hose pat ient s in w hom exposure t o ionizing radiat ion should be limit ed. T his inc ludes pediat ric pat ient s, espec ially if mult iple f ollow - up examinat ions are ant ic ipat ed, and pregnant pat ient s in t heir sec ond and t hird t rimest ers.

Other Modalities for Evaluating Lymphadenopathy Bipedal ly mphangiography (LAG) has been used in t he past t o ev aluat e neoplast ic nodal inv olv ement . In t his proc edure, met hy lene blue is init ially

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2586

17 - Retroperitoneum

injec t ed int o t he dorsal aspec t of t he f oot bet w een t he t oes. T his is pic ked up by t he ly mphat ic s, one of w hic h is t hen exposed and c annulat ed. A small amount of an iodinat ed oil- based c ont rast agent is t hen slow ly injec t ed int raly mphat ic ally . Plain f ilms of t he abdomen are obt ained ov er t he next 24 hours and demonst rat e ly mphat ic f illing and nodal arc hit ec t ure. Neoplast ic inv olv ement is show n by alt erat ion of t he normal nodal arc hit ec t ure (100). Alt hough bipedal LAG w as t he mainst ay of ly mphat ic imaging bef ore t he adv ent of CT and MRI, it has f allen out of f av or f or sev eral reasons (338). T he proc edure it self is t ime- c onsuming, dif f ic ult t o perf orm, and unc omf ort able f or t he pat ient . In pat ient s w it h sev ere c ardiopulmonary P.1202 P.1203 disease, it may be medic ally c ont raindic at ed. F alse–posit iv e ly mphangiograms are not unc ommon and c an be produc ed by benign reac t iv e hy perplasia (191). CT and MRI w ill also demonst rat e nodal groups not rout inely opac if ied during LAG (e.g. periport al, peripanc reat ic , ret roc rural, and mesent eric nodes) as w ell as nodes c omplet ely replac ed by t umor, w hic h w ould not show up on LAG (163). And last , CT and MRI c an ev aluat e bot h t he loc al t umor and ot her abdominal v isc era.

F igure 17- 59 Low - densit y ly mph nodes in an AIDS pat ient w it h My c obac t er ium av ium int r ac ellular e (MAI) inf ec t ion. Cont rast - enhanc ed c omput ed t omography sc ans show hy podense, enlarged nodes (ar r ow s) in t he (A:) paraaort ic region and (B:) small bow el mesent ery f rom c ult ure- prov ed MAI.

MR ly mphangiography uses f erumoxt ran- 10, a c ont rast agent c onsist ing of ult rasmallsuperparamagnet ic iron oxide part ic les (USPIO). When giv en

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2587

17 - Retroperitoneum int rav enously , t he part ic les ac c umulat e in normal nodal t issue t hroughout t he body , w here t hey are t hen phagoc y t osed by mac rophages. T he susc ept ibilit y ef f ec t induc ed by t he iron c auses signal dropout in normal nodes on T 2- or

T 2* - w eight ed images. In nodes w holly or part ly replac ed by t umor, t his signal dropout is not not ed. T he usual analy sis of images depends on c omparison of pre- and post - USPIO c ont rast images (108,321). Init ial st udies using USPIO in t he abdomen and pelv is hav e prov ed promising (108,109,321). In phase III c linic al t rial w it h abdominal and pelv ic malignanc y , sensit iv it y , spec if ic it y , and ac c urac y w ere 80%, 83%, and 81%, respec t iv ely , represent ing an improv ement ov er nonc ont rast MRI in spec if ic it y and ac c urac y (7).

F igure 17- 60 Whipple disease. Enlarged ret roperit oneal (blac k ar r ow s) and mesent eric (w hit e ar r ow ) ly mph nodes are present . Not e t hat t he at t enuat ion v alue of t he ly mph nodes is low er t han t hat of psoas musc le (P). Ao, aort a; c , inf erior v ena c av a; blac k ar r ow head, superior mesent eric v essels; c ur v ed w hit e ar r ow , t hic kened jejunum.

PET has show n ut ilit y in ident if y ing met ast at ic adenopat hy (165,321). T he most c ommon agent in c urrent use is an 18- f lourine labeled gluc ose analog (F DG) t hat is t aken up by met abolic ally ac t iv e c ells, phosphory lat ed, and t rapped. Many t umors, inc luding ly mphoma and lung, breast , esophageal, and c olon c arc inoma show inc reased ac t iv it y on F DG- PET , and in t hese neoplasms, F DG- PET has prov ed usef ul in ident if y ing nodal met ast asis in bot h enlarged and normal- size nodes as w ell as ext ranodal disease (F ig. 17- 65) (165,229,321). F DG- PET has been less suc c essf ul in ot her t umors, inc luding

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2588

17 - Retroperitoneum pulmonary c arc inoid and prost at e c anc er (71,138,321). In t he lat t er, ot her analogs (e.g., 11C- ac et at e and 11C- met hione) hav e show n some v alue. F alse–negat iv e F DG- PET result s are not ed w it h small (great er t han 1 c m) lesions, in low - grade indolent t umors, and in areas adjac ent t o normal

phy siologic ac t iv it y (e.g., uret ers, bladder) (19). F alse–posit iv e result s c an be seen w it h nodal inf lammat ion, in granulat ion t issue, and w here normal phy siologic upt ake is unusual or f oc al P.1204 and mimic s t umor. Alt hough t he inherent poor spat ial resolut ion w it h PET w as an early problem t he dev elopment of c ombined PET /CT unit s and f usion imaging has ov erc ome t hist o some degree.

F igure 17- 61 High- densit y c ry pt oc oc c al ly mphadenopat hy in a pat ient w it h human immunodef ic ienc y v irus inf ec t ion. A: Post c ont rast c omput ed t omography show s high- densit y ly mph nodes in paraaort ic region (ar r ow s), hy dronephrosis in right kidney (RK) result ing f rom uret eric obst ruc t ion by ly mph nodes. K, lef t kidney ; L, liv er; G, gallbladder; S, spleen. B: High- densit y paraaort ic (ar r ow ) and aort oc av al (arrow head) ly mph node displac ing inf erior v ena c av a (I). U, dilat ed right uret er; S, spleen; K, kidney ; L, liv er. C : Low er

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2589

17 - Retroperitoneum

abdominal lev el show s high- densit y ly mph nodes in paraaort ic , aort oc av al, and ret roperit oneal regions (ar r ow s).

F igure 17- 62 Enhanc ing adenopat hy result ing f rom met ast at ic renal c ell c arc inoma. Cont rast - enhanc ed c omput ed t omography sc ans show paraaort ic adenopat hy demonst rat ing het erogeneous (shor t ar r ow ) rim (long ar r ow ) enhanc ement (A) and homogeneous (open ar r ow ) enhanc ement (B). Not e t he large renal mass (M). A, aort a; I, inf erior v ena c av a.

F igure 17- 63 Cast leman disease. Cont rast - enhanc ed c omput ed t omography sc an show s bright ly enhanc ing paraaort ic and ret roc av al adenopat hy (blac k ar r ow s). Splenomegaly (S) is also not ed. I, inf erior v ena c av a; A, aort a.

US has been quit e ac c urat e in det ec t ing ret roperit oneal adenopat hy (55); how ev er, it is of t en dif f ic ult t o obt ain adequat e sc ans of t he low er abdomen bec ause of bow el gas. In obese pat ient s, examinat ion of t he ret roperit oneal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2590

17 - Retroperitoneum area by ult rasound also is dif f ic ult due t o marked at t enuat ion of t he sound beam by t he abundant subc ut aneous and mesent eric f at

F igure 17- 64 Calc if ied ly mphoma bef ore t reat ment . A: Cont rast - enhanc ed c omput ed t omography sc an t hrough t he origin of t he superior mesent eric art ery demonst rat es enlarged ret roc av al and paraaort ic nodes (ar r ow s). Amorphous c alc if ic at ions are not ed in f oc al splenic lesions. Small renal c y st s are present in bot h kidney s. S, spleen; blac k ar r ow , enc ased right renal art ery . B: Comput ed t omography sc an obt ained 7 c m c audad show s c alc if ied mesent eric (M) and ret roc av al ly mphadenopat hy (R), an ext remely at y pic al f eat ure f or unt reat ed ly mphoma. T he rest of t he ret roperit oneal adenopat hy is of sof t t issue densit y . Not e ant erior displac ement of t he aort a (A) and obsc urat ion of t he psoas (P) margin.

Differential Diagnosis Ot her ent it ies, suc h as ret roperit oneal f ibrosis, perianeury smal f ibrosis, sac c ular aort ic aneury sm, and unopac if ied bow el may exhibit f indings on CT or MRI resembling malignant ly mphadenopat hy . How ev er, t he sof t t issue mass seen in idiopat hic ret roperit oneal f ibrosis or perianeury smal f ibrosis usually has a more regular border t han t hat seen w it h malignant ly mphadenopat hy (see F ig. 17- 13). Aort ic aneury sms usually c an be dist inguished f rom ly mphadenopat hy on post c ont rast sc ans. Bow el loops c an t y pic ally be f ollow ed along t heir c ourse and ident if ied. Alt hough t he inf erior ext ent of t he diaphragmat ic c rura, dilat ed lumbar ly mphat ic s, or v asc ular abnormalit ies and anomalies suc h as an enlarged gonadal v ein, a duplic at ed IVC, and a dilat ed azy gos or hemiazy gos v ein c ould c onc eiv ably be c onf used w it h an enlarged ly mph node, c aref ul examinat ion of mult iple c ont iguous sc ans and c onc omit ant

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2591

17 - Retroperitoneum

use of int rav enous iodinat ed c ont rast medium c an separat e t hese ent it ies f rom ly mphadenopat hy (354).

Posttherapy Evaluation An import ant applic at ion of imaging is in t he ev aluat ion of pat ient s w ho hav e undergone radiat ion t herapy or c hemot herapy and hav e a residual ret roperit oneal mass. CT is f requent ly unable t o dist inguish residual f ibrot ic c hanges f rom v iable neoplasm (184,187). Sev eral inv est igat ors hav e show n t hat MRI may be able t o dist inguish post t reat ment f ibrosis f rom residual or rec urrent t umor (67,90,261). Demonst rat ion of unif orm low signal int ensit y (similar t o t hat of musc le) on T 1- and T 2- w eight ed images suggest s t hat t he sof t t issue mass represent s mat ure f ibrosis.

F igure 17- 65 Normal- size node c ont aining malignant c ells and show ing higher F DG- PET signal. A: Axial c ont rast - enhanc ed c omput ed t omography (CT ) sc an show s a small right paraaort ic node (ar r ow ). L, liv er; S, spleen. B: F DG- PET CT show s inc reased ac t iv it y c orresponding t o normal- size node, c onsist ent w it h a small met ast at ic deposit .

P.1205 How ev er, regions of int ermediat e t o high signal int ensit y on T 2- w eight ed images may represent not only v iable t umor but benign proc esses suc h as nec rosis, inf lammat ion, or early f ibrosis. T his is espec ially t rue in t he f irst six mont hs af t er init iat ion of t herapy (261). Caut ion is nec essary bec ause MR signal int ensit ies ref lec t only gross hist ologic c harac t erist ic s and c annot exc lude mic rosc opic f oc i of residual disease. Serial MRI st udies may be of great er v alue t han any one isolat ed examinat ion in monit oring pat ient s w it h suspec t ed rec urrent disease (261). F DG- PET has also been show n t o hav e an

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2592

17 - Retroperitoneum

import ant role in t he ev aluat ion of residual t umor post t herapy , w it h inc reased upt ake seen in masses w it h residual t umor and low er upt ake in f ibrot ic masses (165,272). Ly mphoc eles are c aused by t he int errupt ion of ef f erent ly mphat ic s and t he result ing ac c umulat ion of ly mphat ic f luid in t he ret roperit oneum. T hey are t y pic ally seen f ollow ing ly mphadenec t omy . Spont aneous regression oc c urs in t he majorit y of c ases, how ev er, a f ew may persist . Alt hough usually asy mpt omat ic w hen small, ly mphoc eles may c ause sy mpt oms, inc luding v enous obst ruc t ion and abdominal dist ension, and may bec ome sec ondarily inf ec t ed. T hey appear on CT or MRI as simple nonenhanc ing f luid c ollec t ions w it h a t hin w all and should not be mist aken f or nec rot ic ly mph nodes. Oc c asionally , negat iv e at t enuat ion v alues (HU) are seen in t he f luid and, w hen present , are t hought t o be st rongly suggest iv e of ly mphoc ele. Mural c alc if ic at ion is unc ommon (300,335,364).

Lymphoma Ly mphomas are a c ommon c ause of ret roperit oneal ly mphadenopat hy . As a group, t hey span a w ide v ariet y of c ondit ions ranging f rom indolent slow grow ing malignanc ies t o aggressiv e rapidly f at al disease. Ly mphoma c an be c lassif ied int o t w o major c at egories: Hodgkin ly mphoma, w hic h makes up 20% t o 30% of c ases in t he Unit ed St at es and w est ern Europe, and non- Hodgkin ly mphoma (NHL) (277). Subc lassif ic at ion bey ond t his point has been a sourc e of some c onf usion. T he 2001 World Healt h Organizat ion Classif ic at ion of T umors of t he Hemat opoiet ic and Ly mphomoid T issues is t he most rec ent ef f ort at c onsensus and at t empt s t o def ine subgroups based on a c ombinat ion of morphology , immunophenot y pe, and genet ic and c linic al f eat ures. In t his f ormulat ion, t here are f iv e subgroups of Hodgkin ly mphoma: a nodular ly mphoc y t e predominant f orm and t he f our c lassic subt y pes—nodular sc lerosis, ly mphoc y t e ric h, mixed c ellularit y , and ly mphoc y t e deplet ed. Prognosis is best w it h t he nodular ly mphoc y t e predominant and nodular sc lerosis f orms and w orse f or t he ly mphoc y t e- deplet ed subgroup (277). T he c lassif ic at ion of NHL is c onsiderably more c omplex, and t he reader is ref erred t o t he pat hology lit erat ure f or more det ails (277). Along w it h hist ologic c lassif ic at ion and c linic al present at ion, st aging is import ant in det ermining t herapy . T he Ann Arbor St aging Classif ic at ion Sy st em is used in bot h Hodgkin ly mphoma and NHL and is show n below (277,344):

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2593

17 - Retroperitoneum St age I: Inv olv ement of a single ly mph node region (I) or a single ext raly mphat ic organ or sit e (IE). St age 2: Inv olv ement of t w o or more nodal regions on t he same side of t he

diaphragm (II) or loc alized inv olv ement of an ext raly mphat ic organ or sit e and one or more nodal regions on t he same side of t he diaphragm (IIE). St age III: Inv olv ement of nodes on bot h sides of t he diaphragm (III), w hic h may be ac c ompanied by loc alized inv olv ement of an ext raly mphat ic organ or sit e (IIIE) or spleen (IIIS) or bot h (IIISE). St age IV: Dif f use or disseminat ed inv olv ement of one or more ext raly mphat ic organs w it h or w it hout node P.1206 inv olv ement . Biopsy - doc ument ed inv olv ement of st age IV sit es is denot ed by let t er suf f ixes:M = marrow , L = lung, H = liv er, P = pleura, O = bone, D = skin and subc ut aneous t issue. “ A” is applied t o asy mpt omat ic pat ient s; “ B” t o t hose w it h f ev er, sw eat s, and w eight loss; and “ X” t o t hose w it h bulk disease (great er t han 10 c m f or nodes). T his sc hema is more helpf ul in t herapy and prognosis in Hodgkin ly mphoma t han in NHL. Giv en t he c ont iguous nat ure of spread v ia ly mphat ic s in Hodgkin ly mphoma, t he ext ent of disease direc t ly inf luenc es t herapy . In c ont rast , NHL may spread hemat ogenously and c ommonly present s w it h disc ont iguous ext ensiv e nodal disease w it h more f requent inv olv ement of ext ranodal sit es (F ig. 17- 66). T heref ore, in NHL, t herapy is gov erned more by hist ologic subt y pe, sy mpt oms, and bulk of disease (338,344). Ret roperit oneal nodal inv olv ement is not ed at t he t ime of present at ion in up t o 55% of pat ient s w it h NHL but in only 25% t o 35% of Hodgkin ly mphoma pat ient s (338). CT and MRI are bot h relat iv ely ac c urat e met hods f or det ec t ing int raabdominal and pelv ic ly mphadenopat hy in pat ient s w it h ly mphoma (see F ig. 17- 66) (145). F alse–posit iv e c ases are largely a result of c onf usion w it h unopac if ied bow el loops or normal v asc ular st ruc t ures, a problem t hat is easily resolv ed by rigorous at t ent ion t o t ec hnique. F alse–posit iv e diagnoses may also be a result of misint erpret at ion of ly mphadenopat hy sec ondary t o benign inf lammat ory disease as malignant . F alse–negat iv e int erpret at ions almost alw ay s are sec ondary t o t he inabilit y t o rec ognize replac ed but normal- sized or minimally enlarged ly mph nodes as abnormal (338). Ev en w it h inc reasing experienc e in sc an int erpret at ion c oupled w it h met ic ulous sc anning t ec hniques, t his limit at ion remains a problem f or CT and MRI. PET - CT sc anning

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2594

17 - Retroperitoneum

has been show n t o be usef ul in t his set t ing as w ell as f or monit oring response t o t herapy (229). It should be not ed, t hough, t hat low - grade ly mphomas and some spec if ic t y pes of ly mphoma (e.g., muc osa- assoc iat ed ly mphoid t issue lesions) may not ac c umulat e F DG (125,141,229). It should be emphasized t hat , in pat ient s w it h massiv e ly mphadenopat hy on t he init ial st udy , t he f ollow - up sc ans may not alw ay s rev ert t o normal ev en w hen pat ient s are in c omplet e c linic al remission. F ibrot ic c hanges sec ondary t o prior radiat ion or c hemot herapy may appear eit her as disc ret e, albeit smaller, sof t t issue masses or as a t hin sheat h c ausing obsc urat ion of t he disc ret e out lines of t he aort a and IVC. Unf ort unat ely , CT is inc apable of dif f erent iat ing bet w een v iable residual neoplasm and suc h f ibrot ic c hanges c aused by c hemot herapy or radiot herapy (264). T 2- w eight ed MR images singly or sequent ially , as w ell as PET - CT sc anning, may help in dist inguishing t umor f rom f ibrosis, as disc ussed abov e (229). In dif f ic ult c ases, surgic al or perc ut aneous biopsy may be nec essary f or def init iv e proof .

F igure 17- 66 Burkit t ly mphoma in a pat ient w it h AIDS. A: Axial c ont rast enhanc ed c omput ed t omography show s a large nodal mass (M) f illing muc h of t he ret roperit oneum w it h hy podense lesions seen inv olv ing t he liv er (L) and right kidney (K). T he lef t kidney (LK) is hy dronephrot ic as a result of uret eral c ompression. S, spleen. B: At a low er lev el, t he large nodal mass (M) is seen displac ing t he inf erior v ena c av a (IVC) (I) ant eriorly and t he lef t kidney (LK) lat erally . Bot h kidney s are hy dronephrot ic . K, right kidney ; L, liv er. C : F urt her

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2595

17 - Retroperitoneum

inf eriorly , t he large ret roperit oneal nodal mass (M) displac es t he aort a (ar r ow ) and IVC (arrow head) ant eriorly .

P.1207 Ly mphomat ous adenopat hy is most c ommonly of sof t t issue at t enuat ion (40 t o 50 HU) on nonc ont rast sc ans, alt hough rarely low er at t enuat ion (30 HU) v alues are seen (252). Maximal enhanc ement af t er int rav enous c ont rast injec t ion t y pic ally oc c urred at 1 t o 2 minut es. In one st udy of 25 pat ient s, a small (mean 16 HU) or moderat e (31 HU) enhanc ement inc rement w as seen in 9 and 12 pat ient s, respec t iv ely (252). Pronounc ed enhanc ement (60 HU) w as not ed in 4 pat ient s (252). Inhomogeneous enhanc ement is more c ommon in pat ient s w it h high- grade ly mphoma, w hereas homogeneous enhanc ement is seen more c ommonly in pat ient s w it h low - grade disease (275). Calc if ic at ion in ly mphomat ous nodes may oc c ur f ollow ing t herapy ; how ev er, it may rarely be seen in unt reat ed disease (9). Abnormal ly mph nodes usually hav e a homogeneous MRI appearanc e but may appear inhomogeneous as a result of c alc if ic at ion or nec rosis. In one st udy , more t han 60% of high- grade NHL nodes had an inhomogeneous MR appearanc e (c orresponding t o nec rosis) on T 2- w eight ed images, in c ont rast t o low - grade NHL nodes, w hic h w ere most ly homogeneous. F urt hermore, pat ient s w it h highgrade NHL and a homogeneous signal int ensit y pat t ern had a bet t er surv iv al rat e t han t hose w it h an inhomogeneous pat t ern (270). T he administ rat ion of int rav enous gadolinium c ont rast has been report ed t o improv e t he det ec t abilit y of t he inhomogeneit ies (271).

Testicular Neoplasms T est ic ular neoplasms are t he most c ommon solid t umor in men 15 t o 34 y ears old (30). Hist ologic ally , t he germ c ell t est ic ular t umors are c omposed of dif f erent c ell t y pes but are grouped most c ommonly int o seminomat ous and nonseminomat ous c at egories (30,279). Painless t est ic ular enlargement is t he c lassic present at ion, alt hough painf ul sw elling is also not ed and may mimic orc hit is or epididy mit is (30). Ret roperit oneal, mediast inal, or pulmonary met ast ases may oc c ur w it h only a small t est ic ular mass, part ic ularly in t he nonseminomat ous t umors (279). T reat ment f or bot h seminomat ous and nonseminomat ous t umors begins w it h radic al inguinal orc hiec t omy . Radiat ion t herapy direc t ed at t he ipsilat eral pelv ic and ret roperit oneal nodes is t hen giv en in c ases of seminoma, w it h adjuv ant c hemot herapy used in c ases w it h more ext ensiv e disease (nodes great er t han 5 c m or supradiaphragmat ic nodes

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2596

17 - Retroperitoneum or v isc eral met ast ases) or relapse. In t he nonseminomat ous t umors, t herapeut ic opt ions are less c ert ain. In general, ret roperit oneal ly mph node dissec t ion is used w it h or w it hout adjuv ant c hemot herapy f or loc al disease or disease limit ed t o t he ret roperit oneum (st ages 1 and 2) (30). Ac c urat e det erminat ion of t umor ext ent helps in t he design of radiat ion port s f or seminomas and in t he c hoic e of init ial mode of t reat ment in t he nonseminomat ous group. T est ic ular t umors t end t o met ast asize v ia t he ly mphat ic sy st em. In general, t he t est ic ular ly mphat ic s, w hic h f ollow t he c ourse of t he t est ic ular art eries/v eins, drain direc t ly int o t he ly mph nodes in or near t he renal hilus

(F ig. 17- 67). Af t er inv olv ement of t hese sent inel nodes, t he lumbar paraaort ic nodes bec ome inv olv ed (unilat erally or bilat erally ), f ollow ed by spread t o t he mediast inal and suprac lav ic ular nodes or hemat ogenous disseminat ion t o t he lungs, liv er, and brain (30).

F igure 17- 67 Sc hemat ic diagram show ing ly mphat ic drainage f rom t he t est is and epididy mis. T he t est is drains primarily int o ly mph nodes at or below t he lev el of t he renal hilum, w hereas t he epididy mis drains int o t he dist al aort ic or proximal iliac nodal group.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2597

17 - Retroperitoneum

Dat a f rom a large surgic al series show ed t hat nodal met ast ases f rom t he right t est is t end t o be midline, w it h primary zones of inv olv ement being t he int eraort oc av al, prec av al, and preaort ic ly mph node groups (F ig. 17- 68). P.1208 Nodal met ast ases f rom t he lef t t est is show a predilec t ion f or preaort ic f ollow ed by lef t paraaort ic and int eraort oc av al nodal groups (63,267). In general, t he presenc e of c ont ralat eral disease is unusual in t he absenc e of ipsilat eral or midline inv olv ement . Similarly , suprahilar disease in t he absenc e of inf rahilar inv olv ement is rare (F ig. 17- 69) (63,267). Nodal inv olv ement is also not ed t o be more likely in nodes ant erior t o a line bisec t ing t he aort a t han in post eriorly loc at ed nodes (122).

F igure 17- 68 Int eraort oc av al adenopat hy . T his nodal region (ar r ow ), bet w een t he aort a (A) and inf erior v ena c av a (I), c an be t he f irst sit e of nodal met ast asis f rom ov arian and t est ic ular neoplasms, t y pic ally right - sided primaries.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2598

17 - Retroperitoneum F igure 17- 69 Met ast at ic seminoma. A: Cont rast - enhanc ed axial c omput ed t omography image at t he lev el of t he renal hila show s low - densit y ret roperit oneal ly mph nodes (N) c ausing hy dronephrosis of t he lef t kidney

(LK). RK, right kidney ; L, liv er. B: Large mixed densit y mass is seen in t he lef t t est is.

Inv olv ement of inguinal ly mph nodes is unusual unless t here has been skin inv asion, inadequat e orc hiec t omy , or prev ious operat ion (e.g., herniorrhaphy ) in t he area (160). CT and MRI may be used f or ev aluat ion of ret roperit oneal inv olv ement in t est ic ular c anc er (F ig. 17- 70). T heir sensit iv it y , how ev er, suf f er f rom an inabilit y t o rec ognize t umor in normal- size nodes (less t han 1 c m). CT using a size c rit eria of great er t han or equal t o 10 mm show s a sensit iv it y of 40% and a spec if ic it y approac hing 100% (35,122). Alt hough low ering t he size c rit eria f or a normal ly mph node f rom 10 mm t o 4 mm inc reased t he sensit iv it y of CT t o 97% in one st udy , it w as assoc iat ed w it h a c onc omit ant dec rease in t he spec if ic it y of t he examinat ion (f rom 100% t o 58%) (122,306). CT and MRI also play a role in t he post t herapy f ollow - up of pat ient s w it h t est ic ular c anc er. How ev er, as w it h subst ant ial ly mphomat ous ly mph node inv olv ement , residual ret roperit oneal masses may remain on CT sc ans ev en af t er met ast at ic t est ic ular c arc inoma has been eradic at ed. Suc h P.1209 masses may represent post t reat ment f ibrosis or t erat oma (usually in nonseminomat ous germ c ell t umor); t hey c annot be dist inguished reliably f rom residual v iable neoplasm by CT (307). In some c ases, t umor masses may enlarge despit e c hemot herapy . Alt hough t hese may represent a lac k of response t o c hemot herapy (part ic ularly if t umor markers [e.g., alpha f et oprot ein (AF P) or human c horionic gonadot ropin (HCG)] are inc reasing), it may also represent c onv ersion of t umor t o mat ure or immat ure t erat oma. In t he lat t er c ase, t umor markers are normal (238).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2599

17 - Retroperitoneum

F igure 17- 70 Met ast at ic t est ic ular t eat oma. A and B: Cont rast - enhanc ed axial c omput ed t omography images demonst rat e a het erogeneous mult iloc ular hy podense mass in t he lef t paraaort ic region (ar r ow s). Not e t hat t he mass c ont ains a small amount of f at (ar r ow heads). (Case c ourt esy of J. Kev in Smit h, MD, PhD, Birmingham, AL.)

Other Retroperitoneal Metastasis Ret roperit oneal ly mph nodes are f requent ly inv olv ed in a v ariet y of malignanc ies f rom t he gast roint est inal and genit ourinary t rac t . T he most c ommon c arc inomas assoc iat ed w it h ret roperit oneal ly mphadenopat hy are t est ic ular, prost at ic , c erv ic al, endomet rial, and renal (278). Bec ause of t he abilit y of CT and MRI t o ev aluat e t he liv er, adrenals, and abdominal and pelv ic ly mph nodes simult aneously , t hey hav e been used as part of an abdominal onc ologic surv ey in pat ient s w it h know n malignanc y bot h in primary ev aluat ion and in f ollow - up. In c ont radist inc t ion t o ly mphoma, nodal met ast ases f rom primary epit helial c anc er of t he genit ourinary t rac t f requent ly c ause replac ement w it hout enlarging t he ly mph node, a c ondit ion not disc ernible on rout ine CT or MRI sc ans (178). Ident if y ing v iable t umor in residual nodal masses is also problemat ic f or many of t hese lesions. In t hese c ases, PET using F DG or anot her agent may hav e a signif ic ant role in ident if y ing ot herw ise oc c ult disease. MR ly mphangiography may also play a f ut ure role. A more c omplet e disc ussion of t he role of CT and MRI in pelv ic malignanc ies is c ov ered in Chapt er 20.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2600

17 - Retroperitoneum

F igure 17- 71 Ret roperit oneal hemat oma. A: Cont rast - enhanc ed axial c omput ed t omography image show s mixed at t enuat ion mass (ar r ow s) in t he ret roperit oneum displac ing t he asc ending c olon (C) ant eriorly . P, psoas, B: Coronal rec onst ruc t ion show s ext ent of ret roperit oneal bleed (ar r ow s). L, liv er; K, kidney .

RETROPERITONEAL HEMORRHAGE Ret roperit oneal hemorrhage has a number of et iologies. As prev iously desc ribed, it c an oc c ur sec ondary t o rupt ure of an aort ic aneury sm or at herosc lerot ic aort a. It c an be seen f ollow ing t rauma, w it h injury t o a ret roperit oneal v essel or organ, or in pat ient s w ho hav e undergone perc ut aneous renal biopsy or t ranslumbar aort ography . It may oc c ur spont aneously in pat ient s on ant ic oagulat ion t herapy or w it h a bleeding diat heses or v asc ulit is. Sev eral ret roperit oneal t umors, inc luding renal c ell c arc inoma and angiomy olipoma and adrenal pheoc hromoc y t oma and my elolipoma, as w ell as ret roperit oneal met ast asis may present w it h ret roperit oneal bleeding (5,80,250,278,362). Alt hough ac ut e onset of abdominal pain and dev elopment of an abdominal mass in assoc iat ion w it h a dec reasing hemat oc rit are highly suggest iv e of ret roperit oneal hemorrhage, c linic al signs and sy mpt oms may be ambiguous, delay ed, or misleading (250). T he diagnosis of ret roperit oneal hemorrhage by plain abdominal radiographs lac ks bot h sensit iv it y and spec if ic it y . CT and MRI are bot h ac c urat e noninv asiv e imaging met hods f or det ec t ing ret roperit oneal hemorrhage. On CT sc ans, it appears as an abnormal sof t t issue densit y , eit her w ell loc alized or dif f usely inf ilt rat ing t he ret roperit oneum

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2601

17 - Retroperitoneum (F ig. 17- 71). It s loc at ion and at t enuat ion c harac t erist ic s depend on t he sourc e and durat ion of t he hemorrhage (F igs. 17- 72, 17- 43, 17- 74). Hemorrhage result ing f rom renal P.1210 biopsy or f rom renal t umor is c ent ered around t he kidney , w hereas t hat assoc iat ed w it h a leaking AAA or t ranslumbar aort ography generally surrounds t he aort a bef ore ext ending int o t he adjac ent ret roperit oneum. An ac ut e hemat oma (+70 t o +90 HU) has a higher at t enuat ion v alue t han c irc ulat ing blood bec ause c lot f ormat ion and ret rac t ion c ause great er c onc ent rat ion of

red blood c ells (310,359). Cont rast - enhanc ed CT may doc ument ac t iv e art erial ext rav asat ion eit her as a f oc al high- densit y area surrounded by a large hemat oma or as a dif f use area of high densit y (140). A subac ut e hemat oma of t en has a luc ent halo and a sof t t issue densit y c ent er. A c hronic hemat oma t y pic ally appears as a low - densit y mass (+20 t o +40 HU) w it h a t hic k, dense rim (310). Peripheral c alc if ic at ion also may be present . Alt hough hy perdensit y is quit e spec if ic f or ac ut e hemat oma, t he appearanc e of ret roperit oneal hemorrhage on CT is by no means pat hognomonic . A subac ut e hemat oma c an be c onf used w it h a ret roperit oneal t umor, and a c hronic hemat oma may hav e a similar appearanc e t o an absc ess, ly mphoc ele, c y st , or urinoma. Dif f erent iat ion among t hese ent it ies of t en requires c orrelat ion w it h t he pat ient 's c linic al hist ory . T he use of serial sc anning, w it h dec reasing size and at t enuat ion v alue of t he ret roperit oneal mass, are reassuring signs t hat a t he diagnosis of hemat oma is c orrec t in c ases in w hic h t he c linic al f eat ures are equiv oc al.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2602

17 - Retroperitoneum F igure 17- 72 Bilat eral iliac us hemat omas in a pat ient on ant ic oagulant

t herapy . Non–c ont rast axial c omput ed t omography image show s enlargement of bot h iliac us musc les by masses (ar r ow heads) c ont aining f luid–f luid lev els (ar r ow s). T he dependent port ion is slight ly hy perdense relat iv e t o musc le and represent s set t led blood produc t s, w it h t he low er densit y serum seen ant eriorly .

F igure 17- 73 Psoas hemat oma. Cont rast - enhanc ed axial c omput ed t omography image show s a mixed at t enuat ion mass (ar r ow s) expanding t he psoas musc le. Ext ension int o t he post erior pararenal spac e and lat eral c onal f asc ia (ar r ow heads) is seen w it h displac ement of t he lef t kidney (K) ant eriorly . S, spleen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2603

17 - Retroperitoneum

F igure 17- 74 Psoas hemat oma in a pat ient on ant ic oagulat ion f or at rial f ibrillat ion. Nonc ont rast axial c omput ed t omography image show s a slight ly hy perdense mass expanding t he lef t psoas musc le (ar r ow s).

T he MRI appearanc e of ret roperit oneal hemorrhage depends on not only t he age of t he hemat oma but also t he magnet ic f ield st rengt h. T he signal int ensit y of an ac ut e hemat oma imaged at low magnet ic f ield (0.15 t o 0.5 T ) is less t han or equal t o t hat of musc le on T 1- w eight ed images and higher t han t hat of musc le on T 2- w eight ed images (311). T his is in c ont radist inc t ion t o t he f indings of ac ut e hemat oma w hen examined at high magnet ic f ield (1.5 T ). In t hat set t ing, ac ut e hemat oma has a similar signal int ensit y t o t hat of musc le on T 1- w eight ed images and marked hy point ensit y on T 2- w eight ed images (94). Marked hy point ensit y on T 2- w eight ed images is at t ribut ed t o t he presenc e of int rac ellular deoxy hemoglobin, w hic h c auses T 2 short ening. T his ef f ec t is more pronounc ed on GRE images t han on SE images. A f luid–f luid lev el w it h great er signal in t he dependent lay er on T 1- w eight ed images also has been desc ribed in large, ac ut e hemat omas (105). P.1211 As t he hemat oma ages, it assumes a more c harac t erist ic MRI appearanc e. On T 1- w eight ed images, a subac ut e hemat oma of t en has t hree dist inc t lay ers of signal: a t hin, low - int ensit y rim c orresponding t o t he hemosiderin- laden f ibrous c apsule, a slight ly t hic ker, high- int ensit y (similar t o f at ) peripheral zone, and a medium int ensit y c ent ral c ore (slight ly great er t han musc le) (105,284,326). A similar t hree- ring appearanc e is not ed on T 2- w eight ed images, alt hough t he signal int ensit y of t he c ent ral c ore is great er relat iv e t o t he peripheral zone,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2604

17 - Retroperitoneum w hereas t he rim remains low in int ensit y . Wit h f urt her mat urat ion of t he

hemat oma, t he c ent ral c ore, w hic h represent s t he ret rac t ed c lot , c ont inues t o diminish in size, and t he ent ire hemat oma ev ent ually bec omes a homogeneous high signal int ensit y mass surrounded by a low - int ensit y rim on bot h T 1- and T 2- w eight ed images (F ig. 17- 75). A progressiv e inc rease in signal int ensit y of a hemat oma parallels t he f ormat ion of met hemoglobin (31,284)

F igure 17- 75 Ret roperit oneal hemat oma due t o Coumadin ov erdose. A: Axial nonc ont rast c omput ed t omography sc an show s het erogeneous mass (H) in t he ret roperit oneum. B: Coronal half F ourier snap shot t urbo spin ec ho magnet ic resonanc e image (MRI) show s high signal int ensit y hemat oma (H) w it h low signal rim in right ret roperit oneal c ompart ment . L, liv er. C : Coronal T 1w eight ed MRI show s int ermediat e signal hemat oma w it h low signal rim in right ret roperit oneum. L, liv er.

Alt hough hemat oma may hav e a c harac t erist ic MRI appearanc e, it is import ant t o not e t hat hemorrhage int o a t umor may be indist inguishable f rom a bland hemat oma. F urt hermore, f luid c ont aining high prot ein c ont ent may hav e an

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2605

17 - Retroperitoneum appearanc e similar t o t hat of a resolv ing hemat oma. F luid–f luid lev els result ing f rom t he set t ling of debris w it hin an absc ess may also simulat e t he appearanc e of sediment ed blood.

Bec ause of t he ease w it h w hic h t he diagnosis of ac ut e hemat oma c an be made on CT , CT w ill remain t he proc edure of c hoic e in imaging pat ient s w it h suspec t ed ac ut e ret roperit oneal hemorrhage (less t han 2 w eeks durat ion). How ev er, MRI may prov ide a more spec if ic diagnosis t han CT in less ac ut e c ases in w hic h CT f indings are nonspec if ic . P.1212

RETROPERITONEAL FIBROSIS Ret roperit oneal f ibrosis is c harac t erized by f ibrous t issue prolif erat ion along t he post erior aspec t of t he ret roperit oneum. Alt hough t he proc ess c an oc c ur f rom t he c hest int o t he pelv is, t he most c ommonly inv olv ed area lies bet w een t he renal hila and t he pelv ic brim. Ext ension ant eriorly int o t he mesent ery and post eriorly int o t he epidural spac e hav e also been report ed (166). Vasc ular, uret eral, and ev en c olonic enc asement and obst ruc t ion c an oc c ur (130,274). T he proc ess is more c ommon in men t han in w omen and t y pic ally present s f rom 40 t o 60 y ears of age. Sy mpt oms are usually v ague and poorly loc alized. Dull bac k or f lank pain is most c ommon, alt hough w eight loss, nausea, v omit ing, and malaise are also report ed. An elev at ed ery t hroc y t e sediment at ion rat e is f requent ly seen. Azot emia may oc c ur w it h uret eral obst ruc t ion (166). Hist ologic ally , f ibroblast ic prolif erat ion and c ollagen deposit ion are seen w it h v ary ing amount s of inf lammat ory inf ilt rat e. Early st ages t end t o be highly v asc ular and inf lammat ory , w hereas lat e- st age disease of t en has bec ome more f ibrous and av asc ular (166,278). Alt hough t w o t hirds of c ases are idiopat hic (Ormond disease), c ert ain drugs (e.g., met hy sergide), as w ell as primary or met ast at ic t umors (e.g., ly mphoma and signet ring c arc inoma), hav e all been assoc iat ed w it h similar pat hologic alt erat ions in t he ret roperit oneum (6,278). T he assoc iat ion of f ibrosis and inf lammat ion w it h some aort ic aneury sms w as disc ussed under t he sec t ion on IAAAs. A similar idiopat hic f ibrosing disorder has been report ed in t he c hest (f ibrosing mediast init is), t hy roid (Reidel t hy roidit is), orbit (pseudot umor), and biliary t ree (sc lerosing c holangit is). When t hese oc c ur in c ombinat ion, t he proc ess is ref erred t o as mult if oc al f ibrosc lerosis (278). Eac h disease is t hought t o be a regional v ariat ion of a c ommon immunologic hy persensit iv it y disorder.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2606

17 - Retroperitoneum

F igure 17- 76 Idiopat hic ret roperit oneal f ibrosis. A: Cont rast - enhanc ed c omput ed t omography sc an show s mildly enhanc ing c irc umf erent ial paraaort ic sof t t issue (ar r ow s) enc asing t he inf erior v ena c av a (I) and lef t uret er. Enhanc ement suggest s an ac ut e proc ess or a malignant et iology . B: A f ollow up st udy show s reduc t ion of t he paraaort ic sof t t issue af t er t reat ment w it h t amoxif en. Lac k of enhanc ement is now c onsist ent w it h c hronic f ibrosis.

Ret roperit oneal f ibrosis show s a v ariable appearanc e on CT and MRI (F ig. 1776) Most pat ient s present w it h a w ell- def ined sheat h of periaort ic sof t t issue densit y t hat surrounds t he ant erior and lat eral surf ac es of t he aort a and IVC bet w een t he renal hila and sac ral promont ory . Loss of t he normal f at planes surrounding t hese st ruc t ures and t he psoas musc ulat ure is c ommon. On rare oc c asion, ret roperit oneal f ibrosis may show v ery asy mmet ric inv olv ement or inv olv ement of t he ret roc rural, mesent eric , peripanc reat ic , perirenal, or presac ral regions (17,37,96,241,324,343). It may ev en present as single or mult iple sof t t issue masses w it h irregular borders, an appearanc e quit e similar t o t hat of primary ret roperit oneal t umor or malignant ly mphadenopat hy (312,339). Unlike ret roperit oneal t umors, t he mass t y pic ally does not c ause ant erior displac ement of t he aort a or lat eral displac ement of t he uret ers or result in bony dest ruc t ion (33,60). On nonc ont rast CT sc ans, ret roperit oneal f ibrosis usually has an at t enuat ion v alue similar t o t hat of musc le alt hough f oc al or unif orm hy perdensit y has also been report ed (282, 339). Wit h MRI, ret roperit oneal f ibrosis t y pic ally has a homogeneous low signal int ensit y similar t o t hat of psoas musc le on T 1w eight ed images. T he T 2- w eight ed appearanc e v aries depending on st age and ac t iv it y of disease, w it h early - st age inf lammat ory lesions show ing a hy perint ense signal and lat e- st age lesions show ing a hy point ense signal (F ig.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2607

17 - Retroperitoneum

17- 77) (222). Variable c ont rast enhanc ement is not ed on post c ont rast sc ans, similarly ref lec t ing t he st age and ac t iv it y of disease (282,339). Early - st age inf lammat ory f ibrosis may show exuberant enhanc ement , w hereas lat e st age disease hy poenhanc es (F ig. 17- 78) (282,339). Malignant ret roperit oneal f ibrosis t ends t o hav e a het erogeneous inc reased T 2- w eight ed signal and enhanc ement f ollow ing int rav enous c ont rast administ rat ion) (F igs. 17- 79 and 17- 80). How ev er, bec ause of t he v ariable appearanc e of P.1213 idiopat hic ret roperit oneal f ibrosis, malignant c auses of ret roperit oneal f ibrosis c annot be dif f erent iat ed f rom nonmalignant c auses based on CT or MRI f indings alone (166,282,339). If malignant ret roperit oneal f ibrosis is suspec t ed and def init iv e proof is needed, biopsy is indic at ed. In t hese sit uat ions, it is rec ommended t hat mult iple deep t issue samples be ac quired, bec ause relat iv ely f ew malignant c ells may be admixed w it h inf lammat ory c ells of t he c ollagen net w ork (6,166).

F igure 17- 77 Chronic ret roperit oneal f ibrosis. A: T ransaxial T 1- w eight ed f ast low - angle shot image (repet it ion t ime, 140 millisec onds; ec ho t ime, 4 millisec onds; f lip angle, 80 degrees) show s sharply def ined hy point ense t issue (ar r ow s) enc asing t he aort a (A). I, inf erior v ena c av a. B: Post gadolinium f at sat urat ed T 1- w eight ed spin ec ho image (repet it ion t ime 600 millisec onds; ec ho t ime, 15 millisec onds) show s no enhanc ement of c irc umaort ic t issue.

Alt hough US c an demonst rat e ret roperit oneal f ibrosis as a hy poec hoic mass, CT or MRI are t he modalit ies of c hoic e f or demonst rat ing t he f ull ext ent of disease and assoc iat ed organ c ompromise (282). In pat ient s w ho are azot emic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2608

17 - Retroperitoneum f rom uret eral obst ruc t ion, MRI is pref erred bec ause of t he lac k of nephrot oxic it y of gadolinium- based c ont rast .

PRIMARY RETROPERITONEAL TUMORS Primary ret roperit oneal neoplasms c omprise a rare and div erse group of t umors t hat arise in t he ret roperit oneum but are unassoc iat ed w it h ret roperit oneal v isc era (e.g., adrenals, kidney s, panc reas, ly mph nodes). Lesions may be c harac t erized pat hologic ally as arising f rom eit her mesenc hy mal t issue (c onnec t iv e t issue, f at , musc le, blood v essels) or neurogenic t issue (nerv e or nerv e sheat h, sy mpat het ic ganglia, ec t opic adrenal) or f rom embry onic or not oc hord remnant s (240). Most t umors are malignant . Most t end t o oc c ur in middle age, alt hough t erat omas and neuroblast omas oc c ur in c hildren. Most t umors do not show a st rong sex predilec t ion; how ev er, t erat omas, ganglioneuromas, and leiomy osarc omas are more c ommon in w omen, w it h liposarc omas, malignant f ibrous hist ioc y t omas, and c hordomas more c ommon in men. Pat ient s are generally asy mpt omat ic unt il t he t umors are large. Sy mpt oms, w hic h are of t en v ague or nonspec if ic , are usually produc ed by c ompression of adjac ent st ruc t ures. Abdominal or bac k pain is c ommon and may be produc ed by pressure or enc roac hment on nerv e root s. Low er ext remit y sw elling may be produc ed by v enous c ompression. Compression or dist ort ion of t he gast roint est inal t rac t may produc e anorexia, nausea, or w eight loss w it h c ompression of genit ourinary st ruc t ures c ausing obst ruc t ion, f requenc y or hemat uria (240). T he primary t reat ment f or ret roperit oneal sarc omas is surgery . F iv e- y ear surv iv al rat es are poor bec ause of dif f ic ult y in ac hiev ing a c omplet e surgic al exc ision in t hese of t en large lesions (75,185). T he diagnosis of t umors arising f rom t he ret roperit oneal t issues is readily ac c omplished w it h CT or MRI, ev en w hen t he t umors are relat iv ely small. Suc h neoplasms appear on CT or MRI generally as sof t t issue masses t hat displac e, c ompress, or obsc ure t he normal ret roperit oneal st ruc t ures. Alt hough it may somet imes be dif f ic ult t o dist inguish a t rue ret roperit oneal neoplasm f rom a t umor arising f rom ret roperit oneal v isc era, t he beak sign, phant om organ sign, embedded organ sign and prominent f eeding art ery sign may be usef ul (227). T hese signs, w hen present , suggest t hat t he t umor is arising f rom a spec if ic organ rat her t han t he ret roperit oneal sof t t issue. F or example, t he beak sign oc c urs w hen a mass def orms it s organ of origin int o a beak shape at it s margin. T he phant om organ sign oc c urs w hen a mass originat ing in an organ has bec ome so large t hat t he organ is no longer disc ernable. T he embedded

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2609

17 - Retroperitoneum

organ sign oc c urs w hen t he organ of origin appears embedded in a mass rat her t han def ormed by it . T he prominent f eeding art ery sign is seen w hen a mass originat ing in a spec if ic v isc era c auses enlargement of t he normal art erial supply t o t hat organ (227).

F igure 17- 78 Ac ut e ret roperit oneal f ibrosis. T 2- w eight ed half F ourier snap shot t urbo spin ec ho image A and T 1- w eight ed f ast low - angle shot image (B) show a hy point ense rind of t issue (ar r ow heads) surrounding t he aort a (ar r ow ). C : Axial post gadolinium f at - sat urat ed T 1- w eight ed image show s signif ic ant t issue enhanc ement (ar r ow heads), ref lec t ing t he ext ensiv e c apillary net w ork present bef ore f ibrosis bec omes c hronic . Ar r ow , aort a. D: Cont rast - enhanc ed c omput ed t omography sc an obt ained f ollow ing uret eral st ent plac ement (ar r ow s) show s sof t t issue mass (ar r ow heads) surrounding t he aort a (A).

P.1214 Prov ided t hat some periv isc eral f at is present , CT or MRI c an ac c urat ely def ine t he size, ext ent , and, t o some degree, c omposit ion of t he t umors as

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2610

17 - Retroperitoneum w ell as t heir ef f ec t on neighboring st ruc t ures. Alt hough sagit t al and c oronal images may be part ic ularly usef ul in t his regard, it should be not ed t hat

c ont iguit y does not imply inv asion bec ause c lear planes of separat ion bet w een t umor and organ may be absent ev en w hen no inv asion has oc c urred. Predic t ions as t o def init e inv asion of normal st ruc t ures, w it h implic at ions t ow ard surgic al resec t abilit y , should be of f ered w it h c aut ion. CT and MRI c an usually dif f erent iat e primary ret roperit oneal neoplasms f rom ret roperit oneal ly mphomas. While t he f ormer t end t o be het erogeneous on CT sc ans, ly mphomas are usually homogeneous (52). Alt hough most solid ret roperit oneal t umors hav e an appearanc e similar t o t hat of musc le t issue, it is oc c asionally possible t o suggest a more limit ed dif f erent ial diagnosis based on spec if ic CT or MRI appearanc e (227). F or example, t he presenc e of f at is c harac t erist ic of lipomas and liposarc omas (F igs. 17- 81, 17- 82, 17- 83). Alt hough t erat omas may also c ont ain f at , t hey P.1215 P.1216 usually also show f at –f luid lev els or c alc if ic at ion. A my xoid st oma w it h t he result ant high signal appearanc e on T 2- w eight ed imaging c an be seen w it h some liposarc omas, malignant f ibrous hist ioc y t omas, and neurogenic t umors (371). Large areas of nec rosis c an be seen in any high- grade neoplasm but are t y pic al of leiomy osarc oma (F igs. 17- 84 and 17- 85). Ly mphangiomas, muc inous c y st ic lesions, and neurogenic t umors may show part ially or c omplet ely c y st ic regions. Vasc ularit y also dif f ers among t umor t y pes, w it h ly mphomas and low grade liposarc omas being relat iv ely hy pov asc ular (227). Marked hy perv asc ularit y is not ed in paragangliomas and hemangioperic y t omas. Moderat e hy perv asc ularit y c harac t erizes leiomy osarc oma, malignant f ibrous hist ioc y t oma (MF H), and many of t he ot her sarc omas. Grow t h pat t ern may of f er a c lue t o t he dif f erent ial diagnosis. F or example, neurogenic t umors inv olv ing t he sy mpat het ic ganglia of t en hav e an elongat ed shape as t hey grow along t he sy mpat het ic c hain. Ly mphangiomas, ganglioneuromas, and ly mphomas t end t o insinuat e t hemselv es bet w een st ruc t ures rat her t han c ompressing or displac ing t hem (227,260). When more prec ise preoperat iv e c harac t erizat ion is desired t han imaging f eat ures allow , CT - guided perc ut aneous biopsy c an be undert aken.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2611

17 - Retroperitoneum

F igure 17- 79 Malignant ret roperit oneal f ibrosis result ing f rom met ast at ic breast c anc er. A: Cont rast - enhanc ed c omput ed t omography sc an show s bilat eral obst ruc t iv e hy drouret er (long w hit e ar r ow s) w it h a sheet of abnormal ret roperit oneal sof t t issue (shor t w hit e ar r ow ). B: Inf eriorly , t issue ext ends t o t he right uret er w it h abnormal enhanc ement (c ur v ed w hit e ar r ow ) at t he sit e of obst ruc t ion.

F igure 17- 80 Malignant ret roperit oneal f ibrosis result ing f rom met ast at ic c erv ic al c arc inoma. A: T ransaxial T 2- w eight ed f ast spin ec ho image (repet it ion t ime, 3,500 millisec onds; ec ho t ime, 93 millisec onds) show s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2612

17 - Retroperitoneum

c irc umaort ic t issue (ar r ow s) t hat is slight ly hy perint ense t o psoas musc le (P). Not e t he bilat eral obst ruc t iv e hy dronephrosis f rom disease in t he pelv is. B: On a t ransaxial T 1- w eight ed f ast low - angle shot image (repet it ion t ime, 140 millisec onds; ec ho t ime, 4 millisec onds; f lip angle 80 degrees), t he t issue is isoint ense t o t he psoas musc le. C : T ransaxial post gadolinium T 1- w eight ed f ast low - angle shot image (repet it ion t ime, 140 millisec onds; ec ho t ime, 4 millisec onds; f lip angle, 80 degrees) show s mild enhanc ement of t he t issue.

F igure 17- 81 Ret roperit oneal liposarc oma. Cont rast - enhanc ed c omput ed t omography sc an show s a large ret roperit oneal mass of mixed f at (F ) and sof t t issue (S) at t enuat ion. T he desc ending c olon (ar r ow ) and kidney (K) are displac ed ant eromedially indic at ing t he ret roperit oneal loc at ion of t he t umor.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2613

17 - Retroperitoneum F igure 17- 82 Dedif f erent iat ed liposarc oma. A and B: Cont rast - enhanc ed c omput ed t omography sc ans at t w o lev els of t he midabdomen show a large ret roperit oneal mass of f at (F ), sof t t issue (S), and mixed (M) at t enuat ion displac ing t he desc ending c olon (ar r ow ) and kidney (K) ant eromedially . In c ont rast t o F igure 17- 66, t he mass show s more solid c omponent s, c orresponding t o dedif f erent iat ed t umor. L, liv er.

CT and or MRI also hav e an import ant role in f ollow ing pat ient s af t er t umor resec t ion. In a st udy of 33 pat ient s w it h rec urrent ret roperit oneal sarc oma, 85% had loc al or regional rec urrenc e, w it h almost t hree f ourt hs of rec urrenc es being det ec t ed w it hin 2 y ears of init ial resec t ion. As w it h t he primary lesions, t he majorit y of rec urrent t umors show ed a het erogeneous appearanc e on CT sc ans (102).

Lipoma and Liposarcoma Lipomas and t heir malignant c ount erpart , liposarc omas, are t he most c ommon ret roperit oneal sof t t issue t umors (75,185,278). T hey are usually quit e large at present at ion and c an be mult iple. Liposarc omas c an be c at egorized by t he relat iv e amount of int rac ellular f at and muc inous mat rix t hey c ont ain int o lipogenic , my xoid, and pleomorphic t y pes depending on t he dominant c omponent . Most lipogenic P.1217 t umors are low - grade, w ell- dif f erent iat ed lesions, w it h pleomorphic t umors being high- grade, poorly dif f erent iat ed t umors. My xoid t umors are t he most c ommon t y pe and are t y pic ally of int ermediat e grade (341).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2614

17 - Retroperitoneum

F igure 17- 83 Dedif f erent iat ed liposarc oma. A: Coronal half F ourier snap shot t urbo spin ec ho magnet ic resonanc e image (MRI) show s mixed signal ret roperit oneal mass (M) displac ing right kidney (K) inf eriorly . L, liv er. B: Axial T 1- w eight ed MRI show s hy point ense ret roperit oneal mass (M) medial t o t he liv er (L). P, panc reas; S, spleen. C : Cont rast - enhanc ed T 1- w eight ed MRI show s het erogeneous enhanc ement in t he right ret roperit oneal mass (M). L, liv er; S, spleen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2615

17 - Retroperitoneum F igure 17- 84 Leiomy osarc oma. Cont rast - enhanc ed c omput ed t omography show s a large het erogeneous mass (M) in right ret roperit oneal c ompart ment . T he mass displac es inf erior v ena c av a (arrow head) ant eriorly . L, liv er; K, kidney s.

On CT or MRI, lipomas appear as sharply marginat ed, homogeneous masses w it h CT densit ies equal t o t hat of normal f at and MR appearanc e c onsist ent w it h t hat of simple f at on T 1- and T 2- w eight ed and f at - sat urat ed sequenc es. F ine linear st reaky densit ies may be present along w it h a t hin border of denser t issue t hat def ines t he c apsule. No signif ic ant sof t t issue c omponent is observ ed (82,341). In c ont radist inc t ion, liposarc omas are poorly marginat ed inf ilt rat iv e lesions t hat t y pic ally c ont ain an admixt ure of f at and sof t t issue densit y c omponent s (see F igs. 17- 81, 17- 82, 17- 83). Alt hough w elldif f erent iat ed liposarc oma (lipogenic liposarc oma) may be v irt ually indist inguishable f rom benign lipoma, it more c ommonly c ont ains some solid or inf ilt rat iv e c omponent s t hat t end t o be t hic ker, more P.1218 numerous, and less w ell def ined t han t hose seen w it h lipomas. T hey t y pic ally do not hav e a v isible c apsule and t end t o blend int o t he adjac ent f at . My xoid liposarc omas hav e densit ies less t han t hat of musc le and c loser t o t hat of w at er on CT . On MRI my xoid c omponent s hav e signal int ensit y similar t o t hat of w at er. F ollow ing int rav enous c ont rast , my xoid regions show gradual ret ic ular enhanc ement . Alt hough t hese lesions resemble c omplex c y st s prior t o c ont rast , f ollow ing c ont rast t hey appear more solid. T hey may hav e sharp margins or c alc if ic at ion and most c ommonly do not c ont ain demonst rable f at . Pleomorphic and round c ell liposarc omas show a sof t t issue densit y similar t o t hat of musc le on CT . On T 1- w eight ed MRI, t hey show a signal int ensit y similar t o t hat of musc le, but hav e inc reased signal int ensit y on T 2- w eight ed images, similar t o t hat of f at . It has been suggest ed t hat MRI may be able t o dist inguish bet w een t he low - grade sc lerot ic sof t t issue c omponent somet imes seen in lipogenic and my xoid liposarc omas and t he high- grade sof t t issue c omponent seen in pleomorphic and round c ell liposarc omas. In t he f ormer, t he signal int ensit y on T 2- w eight ed images approximat es t hat of musc le, w hereas t he signal int ensit y of t he pleomorphic c omponent s is signif ic ant ly higher, approximat ing t hat seen w it h f at (156,341).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2616

17 - Retroperitoneum

F igure 17- 85 Ret roperit oneal leiomy osarc oma. Cont rast - enhanc ed c omput ed t omography sc an demonst rat es a large, het erogeneously enhanc ing mass (M) displac ing t he lef t kidney (K) lat erally . Irregular hy podense regions represent t issue nec rosis and c y st ic degenerat ion c ommonly seen in leiomy osarc oma.

Lesions ot her t han lipoma and liposarc oma may also c ont ain f at . A mat ure t erat oma of t he ret roperit oneum may c ont ain f oc i of mat ure f at . It t y pic ally c an be dif f erent iat ed f rom a lipoma or liposarc oma by t he c ommon presenc e of a f at –f luid lev el and c alc if ic at ions, alt hough t hese f indings hav e, on rare oc c asions, been report ed w it h lipoma or liposarc oma (57,171). Adrenal my elolipomas and renal angiomy olipomas may mimic liposarc omas; how ev er, t heir usual origin f rom t he adrenal or kidney should c larif y t he diagnosis. Enlarged v essels are also c ommonly v isible in angiomy olipomas but unusual in liposarc omas (134). Rarely , an angiomy olipoma may originat e in t he perirenal f at and be indist inguishable f rom a perirenal liposarc oma (325). Similarly , my elolipomas hav e been report ed in t he ret roperit oneum and presac ral region independent of t he adrenal (152). A ly mphangioma w it h a high lipid c ont ent c an also simulat e a lipoma on CT sc ans (58,82). A dif f use inc rease in ret roperit oneal and or pelv ic f at may also be seen in Cushing disease, w it h pelv ic lipomat osis, w it h lipoplast ic ly mphadenopat hy , and idiopat hic ally (82). T he sy mmet ric nat ure of t he f at and absenc e of enc apsulat ion is helpf ul in dist inguishing t hese lesions f rom lipomas.

Leiomyosarcoma Leiomy osarc omas are t he sec ond most c ommon t y pe of ret roperit oneal sarc oma (75,112,185) and are more c ommon in w omen t han men. T hey may demonst rat e int rav asc ular or ext rav asc ular grow t h or a c ombinat ion of t he t w o

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2617

17 - Retroperitoneum (112,172). As w it h t he ot her ret roperit oneal t umors, leiomy osarc omas c an be huge, w it h measurement s as great as 35 c m report ed (320). On CT sc ans, t hey t y pic ally present as a w ell- c irc umsc ribed, large musc ledensit y mass w it h areas of low er at t enuat ion c orresponding t o nec rosis (see F igs. 17- 84 and 17- 85). In general, t he areas of nec rosis are more ext ensiv e t han t hat not ed w it h ot her ret roperit oneal malignanc ies (112,175). Int raluminal grow t h is most c ommonly seen inv olv ing t he IVC bet w een t he diaphragm and renal v eins. It t y pic ally expands t he IVC and may ext end int o t he heart (112). T he MRI appearanc e is also quit e het erogeneous. Lesions t y pic ally hav e low t o int ermediat e signal on T 1- w eight ed sequenc es and int ermediat e t o high signal on T 2- w eight ed sequenc es, ref lec t ing t he amount of c y st ic nec rosis present (112,172).

Malignant Fibrous Histiocytoma MF H is t he t hird most c ommon ret roperit oneal sarc oma and has a broad range of hist ologic appearanc es (75,185). F our major subt y pes are ident if ied: st orif orm- pleomorphic , my xoid, giant c ell, and inf lammat ory (161,224). Alt hough most c ases oc c ur in t he ext remit ies, almost any sit e or organ c an be inv olv ed. T he t umor t y pic ally oc c urs in middle age or older pat ient s. It is more c ommon in men t han w omen and usually present s w it h a mass or pain. On CT or MRI, t he lesions hav e a v aried appearanc e, ref lec t ing t he underly ing hist ologic pleomorphism. T umors are usually quit e large and may hav e c irc umsc ribed or ill- def ined margins (161). Het erogeneous at t enuat ion or signal int ensit y may be seen, part ic ularly c ent rally , c onsist ent w it h nec rosis, hemorrhage, or my xoid mat erial. F luid lev els are oc c asionally seen ref lec t ing spont aneous hemorrhage. F at is not seen, w hic h may help t o dist inguish t hese lesions f rom liposarc omas (276). Enhanc ement is quit e v ariable. Calc if ic at ion is seen in only a minorit y of lesions (161). On MRI, t he t umors usually display low or int ermediat e signal on T 1- w eight ed sequenc es w it h high signal int ensit y seen on T 2- w eight ed sequenc es. My xoid mat erial, if present , is t y pic ally hy perint ense P.1219 on T 2- w eight ed sequenc es (224).

Neurogenic Tumors

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2618

17 - Retroperitoneum Neurogenic t umors in t he ret roperit oneum c an be c at egorized int o t hose originat ing f rom ganglion c ells (ganglioneuromas, ganglioneuroblast omas, and neuroblast oma), t hose arising f rom t he paraganglionic sy st em (pheoc hromoc y t omas, paragangliomas), and t hose arising f rom nerv e sheat h

c ells (neurilemomas, neurof ibromas, and malignant nerv e sheat h t umors) (273). Lesions are t y pic ally seen f rom t he adrenal t o t he organ of Zuc kerkandl in a paraspinal loc at ion t hat mirrors t he dist ribut ion of t he sy mpat het ic ganglia. Alt hough neuroblast oma and ganglioneuroblast oma oc c ur in inf anc y and c hildhood, t he remainder of t he neurogenic t umors oc c ur in adult s (273). Most lesions present w it h mass or pain; how ev er, t hey may sec ret e subst anc es, inc luding c at ec holamines, v asoac t iv e pept ides, or androgenic hormones, t hat produc e a v ariet y of sy st emic sy mpt oms. Most neurogenic t umors appear as w ell- def ined, simple or lobulat ed masses. T hey may be elongat ed in shape as t hey f ollow t he c ourse of t he sy mpat het ic nerv es (227) (F igs. 17- 86 and 17- 87). Unlike ot her ret roperit oneal t umors, t hey t end t o insinuat e t hemselv es bet w een v asc ular st ruc t ures w it hout c ausing v asc ular c ompromise or displac ement (260). Calc if ic at ion is c ommon and c an be seen in approximat ely 85% of c ases of neuroblast oma and t o a lesser degree in ot her neurogenic t umors. Most lesions are f airly homogeneous on CT , w it h at t enuat ion similar t o or less t han t hat of musc le (21,117,260,273). Cy st like spac es may be not ed f rom areas of nec rosis or my xoid degenerat ion (155). MRI demonst rat es a low T 1- w eight ed signal w it h moderat e t o markedly high T 2- w eight ed signal int ensit y depending on t he amount of my xoid mat rix (114,273,371). A w horled appearanc e has been seen on T 2- w eight ed images w it h ganglioneuroma (371). Variable enhanc ement is not ed, w it h delay ed enhanc ement desc ribed in t umors w it h my xoid st roma as c ont rast slow ly dif f uses int o t he my xoid regions (371). Paraganglionic t umors are t y pic ally hy perv asc ular w it h marked enhanc ement , w hereas ganglioneuromas show lit t le early enhanc ement (F igs. 17- 88 and 17- 89). Ganglioneuromas also show a t hin c apsule, w hereas neurof ibromas are not enc apsulat ed. T he c y st ic degenerat ion seen in sc hw annomas is also not seen in ganglioneuromas (371). Alt hough c onc ern has been raised about induc ing c at ec holamine release f rom pheoc hromoc y t oma w it h int rav enous c ont rast use, a st udy of 10 pat ient s w it h pheoc hromoc y t omas show ed no inc rease in c irc ulat ing epinephrine or norepinephrine f ollow ing use of nonionic c ont rast (220).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2619

17 - Retroperitoneum

F igure 17- 86 Neurof ibromat osis w it h neurof ibrosarc oma. Cont rast - enhanc ed c omput ed t omography sc an demonst rat es bilat eral slight ly enhanc ing, hy podense masses (M) ext ending along t he c ourse of t he lumbar nerv es and displac ing t he psoas musc les (P) ant eriorly . T he loc at ion is t y pic al f or a neurogenic t umor, and t he gross asy mmet ry should raise suspic ion f or sarc omat ous degenerat ion. A smaller neurof ibroma lies post erior t o t he right t ransv erse proc ess (ar r ow ).

Primary Germ Cell Tumors Ext ragonadal germ c ell t umors are t hought t o eit her arise f rom abnormal migrat ion of primordial germ c ells during embry ogenesis or represent met ast asis f rom oc c ult gonadal primaries. Most ext ragonadal germ c ell t umors oc c ur in t he midline. T he mediast inum is t he most c ommon sit e, f ollow ed by t he ret roperit oneum (226). In c hildren, t here is no st rong sex predilec t ion in eit her benign or malignant germ c ell t umors. Alt hough in adult s, benign t umors hav e similar sex parit y , ov er 90% of malignant ext ragonadal germ c ell t umors oc c ur in men (226). Seminomat ous and nonseminomat ous germ c ell t umors and t erat omas all may oc c ur in t he ret roperit oneum. Most pat ient s present w it h bac k pain or an abdominal mass. Edema sec ondary t o ly mphat ic obst ruc t ion is also not ed. Elev at ion in serum biomarkers suc h as human c horionic gonadot ropin (HCG) and alpha- f et oprot ein (AF P) should be ev aluat ed (226). On CT or MRI, mat ure t erat oma t y pic ally appear as a w ell- def ined mass w it h c y st ic and solid c omponent s c ont aining f at , f luid, and c alc ium. F at may oc c ur in sev eral f orms—solid f at , sebum, and admixed w it h hair—and show

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2620

17 - Retroperitoneum v ariat ion in densit y on CT and signal int ensit y on MRI (49). F at –f luid lev els may be not ed and are st rongly suggest iv e of t erat oma (86). Malignant germ

c ell t umors appear as large, lobulat ed masses w it h mixed densit y c omponent s. T he low - densit y regions presumably c orrespond t o areas of nec rosis or old hemorrhage (28).

Other Retroperitoneal Tumors A v ariet y of ot her neoplasms may inv olv e t he ret roperit oneum. Most are quit e rare, but sev eral hav e dist inc t iv e imaging c harac t erist ic s. Ly mphangioma t y pic ally appears as a w ell- c irc umsc ribed, elongat ed, unic ameral or sept at ed P.1220 f luid- f illed mass. Sept ae are usually smoot h and t hin alt hough approximat ely 20% show ed t hic ker irregular w alls. Calc if ic at ion is unusual. F luid is usually homogeneous and near w at er densit y , alt hough a lesion c ont aining c hy le w it h f at densit y has been report ed. High signal int ensit y on T 2- w eight ed imaging is t y pic al. T 1- w eight ed signal is usually low unless hemorrhage has oc c urred (135). Lay ering debris may also be not ed (58,183). Ot her rare c y st ic lesions of t he ret roperit oneum inc lude primary muc inous c y st adenoma, c y st ic t erat oma, c y st ic mesot helioma, and a v ariet y of c ongenit al lesions (epidermoid, t ailgut , bronc hogenic c y st s), as w ell as c y st ic c hange in solid neoplasms (e.g., paraganglioma) (364). Hemangioperic y t omas are large, c omplex masses show ing mult iple areas of irregular low densit y c orresponding t o regions of nec rosis or hemorrhage. Hy perv asc ularit y in solid areas is c harac t erist ic but c an also be f ound in leiomy osarc oma and MF H (4,91).

F igure 17- 87 Neurof ibromat osis w it h neurof ibromas. A: T 2- w eight ed magnet ic resonanc e image demonst rat es hy perint ense lobulat ed masses (ar r ow s)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2621

17 - Retroperitoneum ext ending f rom t he neural f oramina bilat erally and displac ing t he psoas (P) ant erolat erally . B: T 1- w eight ed image show s t he masses (ar r ow s) t o be similar t o musc le in signal int ensit y .

F igure 17- 88 Ret roperit oneal paraganglioma. Cont rast - enhanc ed c omput ed t omography image show s a het erogeneously enhanc ing mass (M) in t he region of t he sec ond part of t he duodenum. Mass displac es t he inf erior v ena c av a (ar r ow ) post eriorly and panc reat ic head (P) ant eromedially . K, kidney ; L, liv er.

PSOAS Normal Anatomy T he psoas major, psoas minor, and iliac us musc les are a group of musc les t hat f unc t ion as f lexors of t he t high and t runk. T he psoas major musc le originat es f rom f ibers arising f rom t he t ransv erse proc esses of t he 12t h t horac ic v ert ebra as w ell as all lumbar v ert ebrae. T he musc le f ibers f use and pass inf eriorly in a paraspinal loc at ion. As it exit s f rom t he pelv is, t he psoas major assumes a more ant erior loc at ion, merging w it h t he iliac us t o bec ome t he iliopsoas musc le. T he iliopsoas passes beneat h t he inguinal ligament t o insert on t he lesser t roc hant er of t he f emur. At it s superior at t ac hment , t he psoas musc le passes beneat h t he arc uat e ligament of t he diaphragm. T he psoas musc le is in a f asc ial plane t hat direc t ly ext ends f rom t he mediast inum t o t he t high. T he psoas minor is a long, slender musc le, loc at ed immediat ely ant erior t o t he psoas major. When present , it arises f rom t he sides of t he body of t he 12t h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2622

17 - Retroperitoneum

t horac ic and f irst lumbar v ert ebrae and f rom t he f ibroc art ilage bet w een t hem. It ends in a long, f lat t endon t hat insert s on t he iliopec t ineal eminenc e of t he innominat e bone. On CT or MRI sc ans, t he normal psoas major musc les are delineat ed c learly in almost ev ery pat ient as paired paraspinal st ruc t ures. T he proximal port ion of t he psoas P.1221 musc le is t riangular in shape, w hereas t he dist al end has a more rounded appearanc e. T he size of t he psoas major musc le inc reases in a c ephaloc audad direc t ion. When v isible, espec ially in y oung, musc ular indiv iduals, t he psoas minor appears as a small, rounded, sof t t issue mass ant erior t o t he psoas major (F ig. 17- 90). Caut ion must be t aken not t o c onf use t his musc le w it h an enlarged ly mph node. T he sy mpat het ic t runk as w ell as t he lumbar v eins and art eries are somet imes seen as small sof t t issue densit ies loc at ed just medial t o t he psoas musc les and lat eral t o t he lumbar spine. How ev er, dif f erent iat ion bet w een an art ery , a v ein, and a nerv e in t his loc at ion is not possible on nonc ont rast sc ans.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2623

17 - Retroperitoneum F igure 17- 89 Ret roperit oneal sc hw annoma. A: Cont rast - enhanc ed c omput ed t omography image show s a large paraaort ic mass (M) displac ing t he aort a (ar r ow head) and inf erior v ena c av a (ar r ow ) t o t he right . P, psoas. B: Mass (M) ext ends along t he lef t c ommon iliac art ery (ar r ow head), displac ing it t o t he right . C : Mass is seen in t he low er pelv is displac ing lef t f emoral art ery

ant eromedially and t he bladder, w it h c ont ained F oley c at het er (F ), t o t he lef t .

T he psoas musc le has low signal int ensit y on bot h T 1- and T 2- w eight ed images. A T 1- w eight ed pulse sequenc e prov ides t he best c ont rast bet w een t he musc le and adjac ent ret roperit oneal f at ; bot h T 2- w eight ed and post gadolinium, T 1- w eight ed, f at - suppressed sequenc es c an c learly dif f erent iat e normal musc le f rom most pat hologic c ondit ions (180,346). T o ev aluat e t he psoas musc le, images in t he t ransaxial plane should be obt ained. If an abnormalit y is not ed in t he musc le, addit ional c oronal or sagit t al v iew s may help delineat e t he ext ent of disease and det ermine if t here is inv olv ement of t he spine (346).

Pathology Neoplasm A pat hologic proc ess c an inv olv e t he psoas musc le by one of t hree mec hanisms: (a) replac ement , (b) medial displac ement , and (c ) lat eral displac ement (180). Ly mphoma, ot her malignant P.1222 ret roperit oneal neoplasms, and met ast asis may exhibit eac h of t hese appearanc es and result in a f oc al lesion, enlargement , or obsc urat ion of t he psoas musc le. T he inv olv ed musc le most of t en has a CT at t enuat ion v alue similar t o t he normal one, alt hough areas of low at t enuat ion also may be present (76). On MRI, t he abnormal musc le has signal int ensit y higher t han t hat of normal psoas on bot h T 1- and T 2- w eight ed images. On T 1- w eight ed images, t he signal int ensit y of t he diseased musc le is less t han t hat of f at unless hemorrhage has oc c urred, in w hic h c ase a high int ensit y signal may be observ ed in t he abnormal region. Bec ause of it s superior c ont rast sensit iv it y , MRI is superior t o CT in separat ing normal f rom abnormal psoas musc le. We hav e enc ount ered c ases in w hic h t he CT st udy show ed apparent enlargement of t he psoas musc le and subsequent MRI examinat ion demonst rat ed t hat t he psoas musc le w as c ompressed and displac ed lat erally by a mass (180) (F ig.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2624

17 - Retroperitoneum 17- 91). How ev er, neit her examinat ion c an reliably dif f erent iat e mere c ont iguit y f rom superf ic ial inv asion.

F igure 17- 90 T he psoas minor musc le (ar r ow head), prominent in some musc ular indiv iduals, should not be c onf used w it h an enlarged ly mph node. Ao, aort a; c , inf erior v ena c av a.

Inflammatory Lesions Inf ec t ion w it hin t he psoas musc le may oc c ur eit her f rom direc t ext ension f rom c ont iguous st ruc t ures (sec ondary psoas absc ess), suc h as t he spine, kidney , bow el, and panc reas, or w it hout a def init e sourc e (primary psoas absc ess), in w hic h c ase t he inf ec t ion is presumed t o hav e arisen f rom hemat ogenous seeding (76,287,372). Wit h t he dec reasing inc idenc e in t uberc ulous inv olv ement of t he spine, t he majorit y of psoas absc esses now enc ount ered are of a py ogenic origin (76,372). On CT sc ans, t he inv olv ed psoas musc le is of t en enlarged, w it h an absc ess appearing as a f oc al low densit y area (0 HU t o 30 HU) (F igs. 17- 92 and 17- 93) (76). T he size and ext ent of t he absc ess usually c an easily be delineat ed; v isualizat ion of t he absc ess is improv ed by int rav enous administ rat ion of iodinat ed c ont rast mat erial. Gas is not ed in approximat ely P.1223 P.1224 40% t o 50% of c ases (76,372). Psoas absc ess c an likew ise be det ec t ed by MRI (F ig. 17- 94). Absc esses hav e a signal int ensit y equal t o or great er t han t hat of normal musc le on T 1- w eight ed images and a high signal int ensit y on T 2- w eight ed images (180,346). A major limit at ion of MRI is it s inabilit y t o

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2625

17 - Retroperitoneum c onsist ent ly det ec t small c ollec t ions of air t hat may be present w it hin t he absc ess. If det ec t ed, a c ollec t ion of air w ould appear as a f oc al region of signal v oid on bot h T 1- and T 2- w eight ed images. How ev er, a f oc al c alc if ic at ion in t he musc le c ould hav e a similar appearanc e. My osit is w it hout f rank absc ess f ormat ion has also been desc ribed and appears as musc le enlargement w it h inc reased T 2- w eight ed signal c orresponding t o edema (95,361). In many c ases, CT or MRI c an help eluc idat e a sourc e of inf ec t ion suc h as appendic it is, Crohn disease, perirenal absc ess, disc it is, or sac roileit is (372).

F igure 17- 91 Non- Hodgkin ly mphoma abut t ing lef t psoas musc le. A: Cont rast enhanc ed c omput ed t omography (CT ) show s enlargement of lef t psoas musc le by mass (M). Mass is not w ell delineat ed f rom musc le on CT . B: T 1- w eight ed magnet ic resonanc e image demonst rat es mass (M) displac ing psoas musc le (P) post erolat erally . Mass is slight ly hy perint ense relat iv e t o musc le.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2626

17 - Retroperitoneum

F igure 17- 92 Psoas absc ess f rom an inf ec t ed urinoma. A: Cont rast - enhanc ed c omput ed t omography (CT ) sc an show s a f luid c ollec t ion (F ) t rac king w it hin t he right psoas musc le. Not e t he obst ruc t ing renal c alc ulus (blac k ar r ow ) and t he c ommunic at ion of t he psoas c ollec t ion w it h t he right perinephric spac e (w hit e ar r ow ). B: CT sc an at t he lev el of t he ac et abulum demonst rat es t he inf erior ext ent of t his f luid c ollec t ion t o be loc at ed at t he sit e of t he right psoas musc le at t ac hment . Not e t he enhanc ement of it s w all and sept at ions. Cult ure grew Esc her ic hia c oli. U, ut erus; open ar r ow , ext ernal iliac art ery .

F igure 17- 93 Absc ess around aort of emoral graf t : A: Cont rast - enhanc ed c omput ed t omography sc an show s t he proximal end of t he aort of emoral graf t (ar r ow head). L, liv er; S, spleen. B: At a low er lev el, a rim- enhanc ing low densit y c ollec t ion c ont aining air (ar r ow s) is seen surrounding t he graf t (ar r ow head). K, kidney . T he medial limb of t he graf t is pat ent ; t he lat eral limb is t hrombosed. C : At t he lev el of t he iliac c rest , t he low - densit y c ollec t ion w it h air (ar r ow s) is seen ext ending around t he graf t (ar r ow head). D: Perc ut aneous plac ement of a drainage c at het er (ar r ow heads) allow s resolut ion of t he absc ess.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2627

17 - Retroperitoneum

F igure 17- 94 Crohn disease w it h psoas absc ess. A: Coronal T 2- w eight ed half F ourier snap shot t urbo spin ec ho (HAST E) magnet ic resonanc e (MR) image show s high signal int ensit y f luid c ollec t ion (ar r ow heads) in right psoas musc le. L, liv er; P, normal lef t psoas. B: Axial T 2- w eight ed HAST E MRI show s inf erior port ion of high signal int ensit y absc ess ext ending int o right iliopsoas musc le (ar r ow heads). Not e phlegmonous c hange around t he c ec um (C). P, lef t psoas. C : Axial T 1- w eight ed MRI show s int ermediat e signal c ollec t ion (ar r ow heads) v irt ually replac ing t he right psoas musc le. D: Axial T 1- w eight ed c ont rast enhanc ed f at - sat urat ed MRI show s int ense rim enhanc ement (ar r ow heads) around psoas absc ess. Abnormal enhanc ement is also seen in t he phlegmonous c hange about t he c ec um (C).

Enlargement of a psoas musc le w it h areas of low er densit y is not spec if ic f or an inf lammat ory proc ess. In a st udy P.1225 of 44 pat ient s w it h iliopsoas absc ess, t umor or hemat oma, a c orrec t diagnosis w as made in only 48% of pat ient s w hen c linic al dat a w ere w it hheld (181). Irregular margins w ere seen in 67% of t umors but also 52% of absc esses. Low

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2628

17 - Retroperitoneum at t enuat ion w as not ed in 100% of absc esses but also 67% of t umors. Dif f use inv olv ement of t he musc le w as seen in 88% of hemat omas but only 19% of

absc esses. Alt hough gas is usually signif ic ant ly more c ommon in absc ess t han t umor (76), in t his series, gas w as not ed in t hree neoplasms and t w o absc esses (181). Gas has also been report ed in t he psoas musc le sec ondary t o an int rav ert ebral v ac uum c lef t (330). In c ases in w hic h t he CT f indings are nonspec if ic , CT c an be used t o guide perc ut aneous needle aspirat ion of t he observ ed abnormalit y t o obt ain t issue f or hist ologic examinat ion and bac t eriologic c ult ure. In c ases in w hic h t he diagnosis of psoas absc ess is c ert ain, CT c an be used t o guide perc ut aneous drainage (42,372).

F igure 17- 95 Psoas at rophy . Not e absenc e of lef t psoas musc le in t his pat ient w it h a hist ory of polio. T he right psoas is normal.

Other Conditions Alt hough t he psoas may undergo spont aneous hemorrhage due t o ov erant ic oagulat ion, a hemat oma inv olv ing t his musc le also c an result f rom a leaking aort ic aneury sm. As ment ioned prev iously , t he CT at t enuat ion v alue of a hemat oma v aries f rom about +20 HU t o +90 HU, depending upon it s age (see F ig. 17- 73). Hemat oma, absc ess, and neoplasm, w it h or w it hout c ent ral nec rosis, all c an hav e a similar CT appearanc e (181). MRI may be helpf ul in c ases of hemorrhage by demonst rat ing t he c harac t erist ic inc reased signal on T 1- and T 2- w eight ed images of subac ut e blood (346). At rophy of t he psoas musc le sec ondary t o neuromusc ular disorders is similarly easily ident if ied and appears as a unif orm dec rease in t he size of t he musc le bulk on t he inv olv ed side (F ig. 17- 95). On oc c asion, t he inv olv ed musc les hav e low densit y on CT bec ause of part ial f at t y replac ement .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2629

17 - Retroperitoneum REFERENCES 1. Adriaensen ME, Bosc h JL, Halpern EF , et al. Elec t iv e endov asc ular v ersus open surgic al repair of abdominal aort ic aneury sms: sy st emat ic rev iew of short - t erm result s. Radiology 2002; 224:739–747. 2. Akkersdijk GJ, v an Boc kel JH. Rupt ured abdominal aort ic aneury sm: init ial misdiagnosis and t he ef f ec t on t reat ment . Eur J Sur g 1998;164:29–34.

3. Aljabri B, Mac Donald PS, Sat in R, et al. Inc idenc e of major v enous and renal anomalies relev ant t o aort oiliac surgery as demonst rat ed by c omput ed t omography . Ann Vasc Sur g 2001; 15:615–618. 4. Alpern MB, T horsen MK, Kellman GM, et al. CT appearanc e of hemangioperic y t oma. J Com put Assist T om ogr 1986;10:264–267. 5. Amano T , T akemae K, Niikura S, et al. Ret roperit oneal hemorrhage due t o spont aneous rupt ure of adrenal my elolipoma. Int J Ur ol 1999;6:585–588. 6. Amis ES. Ret roperit oneal f ibrosis. AJR Am J Roent genol 1991; 157: 321–329. 7. Anzai Y , Pic c oli CW, Out w at er EK, et al. Ev aluat ion of nec k and body met ast ases t o nodes w it h f erumoxt ran10- enhanc ed MR imaging: phase III saf et y and ef f ic ac y st udy . Radiology 2003;228:777–788. 8. Applegat e KE, Goske MJ, Pierc e G, et al. Sit us rev isit ed: imaging of t he het erot axy sy ndrome. Radiogr aphic s 1999;19:837–852; disc ussion 853–854. 9. Apt er S, Av igdor A, Gay er G, et al. Calc if ic at ion in ly mphoma oc c urring bef ore t herapy : CT f eat ures and c linic al c orrelat ion. AJR Am J Roent genol 2002;178:935–938. 10. Arit a T , Mat sunaga N, T akano K. Abdominal aort ic aneury sm: rupt ure assoc iat ed w it h t he high- at t enuat ing c resc ent sign. Radiology 1997;204:765–768. 11. Armerding MD, Rubin GD, Beaulieu CF , et al. Aort ic aneury smal disease: assessment of st ent - graf t t reat ment - CT v ersus c onv ent ional angiography . Radiology 2000;215:138–146. 12. Arriv e L, Hric ak H, T av ares NJ, et al. Malignant v ersus nonmalignant ret roperit oneal f ibrosis: dif f erent iat ion w it h MR imaging. Radiology 1989;172:139–143. 13. Arriv e L, Menu Y , Dessart s I, et al. Diagnosis of abdominal v enous t hrombosis by means of spin- ec ho and gradient - ec ho MR imaging: analy sis w it h rec eiv er operat ing c harac t erist ic c urv es. Radiology 1991;181:661–668.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2630

17 - Retroperitoneum 14. Arriv e L, Correas JM, Lesec he G, et al. Inf lammat ory aneury sms of t he abdominal aort a: CT f indings. AJR Am J Roent genol 1995;165:1481–1484. 15. Auf f ermann W, Olof sson PA, Rabahie GN, et al. Inc orporat ion v ersus inf ec t ion of ret roperit oneal aort ic graf t s: MR imaging f eat ures. Radiology 1989;172:359–362. P.1226 16. Av ila NA, Kelly JA, Chu SC, et al. Ly mphangioleiomy omat osis: abdominopelv ic CT and US f indings. Radiology 2000;216:147–153. 17. Ay uso JR, Garc ia- Criado A, Caralt T M, et al. At y pic al ret roperit oneal f ibrosis: MRI f indings. Eur Radiol 1999;9:937–939. 18. Badler R, Pric e AP, Moy L, et al. Congenit al port ac av al shunt : CT demonst rat ion. Pediat r Radiol 2002;32:28–30.

19. Barringt on SF , O'Dohert y MJ. Limit at ions of PET f or imaging ly mphoma. Eur J Nuc l Med Mol Im aging 2003;30[suppl 1]:S117–S127. 20. Basile A, Cert o A, Asc ent i G, et al. Embry ologic and ac quired anomalies of t he inf erior v ena c av a w it h rec urrent deep v ein t hrombosis. Abdom Im aging 2003;28:400–403. 21. Bass JC, Korobkin M, F ranc is IR, et al. Ret roperit oneal plexif orm neurof ibromas: CT f indings. AJR Am J Roent genol 1994;163: 617–620. 22. Bass JE, Redw ine MD, Kramer LA, et al. Absenc e of t he inf rarenal inf erior v ena c av a w it h preserv at ion of t he suprarenal segment as rev ealed by CT and MR v enography . AJR Am J Roent genol 1999;172:1610–1612. 23. Bass JE, Redw ine MD, Kramer LA, et al. Spec t rum of c ongenit al anomalies of t he inf erior v ena c av a: c ross- sec t ional imaging f indings. Radiogr aphic s 2000;20:639–652. 24. Bassilios N, T assart M, Rest oux A, et al. Inf erior v ena c av a t hrombosis due t o ac ut e py elonephrit is. Nephr ol Dial T r ansplant 2004;19:981–983. 25. Bec ht old RE, Dy er RB, Zagoria RJ, et al. T he perirenal spac e: relat ionship of pat hologic proc esses t o normal ret roperit oneal anat omy . Radiogr aphic s 1996;16:841–854. 26. Bert ges DJ, Chow K, Wy ers MC, et al. Abdominal aort ic aneury sm size regression af t er endov asc ular repair is endograf t dependent . J Va sc Surg 2003;37:716–723. 27. Bhalla S, Menias CO, Heiken JP. CT of ac ut e abdominal aort ic disorders. Radiol Clin Nor t h Am 2003;41:1153–1169. 28. Blomlie V, Lien HH, F ossa SD, et al. CT in primary malignant germ c ell t umors of t he ret roperit oneum. Ac t a Radiol 1991;32:155–158.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2631

17 - Retroperitoneum

29. Blum U, Wildanger G, Windf uhr M, et al. Preoperat iv e CT and MR imaging of inf erior v ena c av a leiomy osarc oma. Eur J Radiol 1995;20:23–27. 30. Bosl GJ, Mot zer RJ. T est ic ular germ- c ell c anc er. N Engl J Med 1997;337:242–253. 31. Bradley WGJ, Sc hmidt PG. Ef f ec t of met hemoglobin f ormat ion on t he MR appearanc e of subarac hnoid hemorrhage. Radiology 1985;156:99–103. 32. Broc hert A, Rey nolds T . Unusual duplic at ion anomaly of t he inf erior v ena c av a w it h normal drainage of t he right IVC and hemiazy gous c ont inuat ion of t he lef t IVC. J Vasc Int er v Radiol 2001;12:1453–1455. 33. Brooks AP, Reznek RH, Webb JAW. Aort ic displac ement on c omput ed t omography of idiopat hic ret roperit oneal f ibrosis. Clin Radiol 1989;40:51–52. 34. Brow n PM, Pat t enden R, Gut elius JR. T he selec t iv e management of small abdominal aort ic aneury sms: t he Kingst on st udy . J Vasc Sur g 1992;125:21–27. 35. Bussar- Maat z R, Weissbac h L. Ret roperit oneal ly mph node st aging of t est ic ular t umours: T NM st udy group. Br J Ur ol 1993; 72:234–240. 36. Busut t il SJ, Goldst one J. Diagnosis and management of aort oent eric f ist ulas. Sem in Vasc Sur g 2001;14:302–311. 37. Buy l L, Oost erlinc k W, Verst raet e K, et al. An unusual c ase of unilat eral periuret eral ret roperit oneal f ibrosis. Clin Radiol 2003;58: 492–494. 38. Callen PW, Korobkin M, Isherw ood I. Comput ed t omographic ev aluat ion of t he ret roc rural prev ert ebral spac e. AJR Am J Roe ntge nol 1977;129:907–910. 39. Calligaro KD, Veit h F J. Diagnosis and management of inf ec t ed prost het ic aort ic graf t s. Sur ger y 1991;110:805–813. 40. Calligaro KD, Bergen WS, Sav arese RP, et al. Primary aort oduodenal f ist ula due t o sept ic aort it is. J Car diov asc Sur g (T or ino) 1992;33:192–198. 41. Calligaro KD, Ahmad S, Dandora R, et al. Venous aneury sms: surgic al indic at ions and rev iew of t he lit erat ure. Sur ger y 1995;117:1–6. 42. Cant asdemir M, Kara B, Cebi D, et al. Comput ed t omography - guided perc ut aneous c at het er drainage of primary and sec ondary iliopsoas absc esses. Clin Radiol 2003;58:811–815. 43. Carriero A, Iezzi A, Margarelli N, et al. Magnet ic resonanc e angiography and c olour- Doppler sonography in t he ev aluat ion of abdominal aort ic aneury sms. Eur Radiol 1997;7:1495–1500. 44. Cast ellino RA. Ly mph nodes of t he post erior iliac c rest : CT and ly mphographic observ at ions. Radiology 1990;175:687–689.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2632

17 - Retroperitoneum

45. Cast ruc c i M, Mellone R, Vanzulli A, et al. Mural t hrombi in abdominal aort ic aneury sms: MR imaging c harac t erizat ion—usef ul bef ore endov asc ular t reat ment ? Radiology 1995;197:135–139. 46. Cat asc a JV, Mirow t it z SA. T 2- w eight ed MR imaging of t he abdomen: f ast spin- ec ho v s c onv ent ional spin- ec ho sequenc es. AJR Am J Roent genol 1994;162:61–67. 47. Chee Y L, Culligan DJ, Wat son HG. Inf erior v ena c av a malf ormat ion as a risk f ac t or f or deep v enous t hrombosis in t he y oung. Br J Haem at ol 2001;114:878–880. 48. Chesson JP, T heodoresc u D. Adrenal t umor w it h c av al ext ension—c ase report and rev iew of t he lit erat ure. Sc and J Ur ol Nephr ol 2002;36:71–73. 49. Choi BI, Chia JG, Kim SH, et al. MR imaging of ret roperit oneal t erat oma: c orrelat ion w it h CT and pat hology . J Com put Assist T om ogr 1989;13:1083–1086. 50. Cil BE, Akpinar E, Karc aalt inc aba M, et al. Case 76: May - T hurner sy ndrome. Radiology 2004;233:361–365. 51. Coady MA, Rizzo JA, Hammond GL, et al. Penet rat ing ulc er of t he t horac ic aort a: w hat is it ? How do w e rec ognize it ? How do w e manage it ? J Vasc Sur g 1998;27:1006–1016. 52. Cohan RH, Baker ME, Cooper C, et al. Comput ed t omography of primary ret roperit oneal malignanc ies. J Com put Assist T om ogr 1988;12:804–810. 53. Coulam CH, Rubin GD. Ac ut e aort ic abnormalit ies. Sem in Roent genol 2001;36:148–164. 54. Cura M, Cura A, Bugnone A. Early enhanc ement of t he inf erior v ena c av a on helic al CT . Clin Im aging 2003;27:236–238. 55. Damgaard- Pedersen K, v on der Masse H. Ult rasound and ult rasound guided biopsy , CT and ly mphography in t he diagnosis of ret roperit oneal met ast ases in t est ic ular c anc er. Sc and J Ur ol Nephr ol 1991;137:139–144. 56. Dav idov ic LB, Kost ic DM, Cv et kov ic SD, et al. Aort o- c av al f ist ulas. Car diov asc Sur g 2002;10:555–560. 57. Dav idson AJ, Hart man DS, Goldman SM. Mat ure t erat oma of t he ret roperit oneum: radiologic , pat hologic , and c linic al c orrelat ion. Radiology 1989;172:421–425. 58. Dav idson AJ, Hart man DS. Ly mphangioma of t he ret roperit oneum: CT and sonographic c harac t erist ic s. Radiology 1990;175: 507–510.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2633

17 - Retroperitoneum 59. de Bree E, Klaase JM, Sc hult ze Kool LJ, et al. Aneury sm of t he inf erior v ena c av a c omplic at ed by t hrombosis mimic king a ret roperit oneal neoplasm. Eur J Vasc Endov asc Sur g 2000;20:305–307.

60. Degesy s GE, Dunnic k NR, Silv erman PM, et al. Ret roperit oneal f ibrosis: use of CT in dist inguishing among possible c auses. AJR Am J Roent genol 1986;146:57–60. 61. Didier D, Rac le A, Et iev ent JP, et al. T umor t hrombus of t he inf erior v ena c av a sec ondary t o malignant abdominal neoplasms: US and CT ev aluat ion. Radiology 1987;162:83–89. 62. Dobrin PB. Pat hophy siology and pat hogenesis of aort ic aneury sms: c urrent c onc ept s. Sur g Clin Nor t h Am 1989;69:687–703. 63. Donohue JP, Zac hary JM, May nard B. Dist ribut ion of nodal met ast ases in nonseminomat ous t est is c anc er. J Ur ol 1982;128: 315–330. 64. Dooms GC, Hric ak H, Moseley ME, et al. Charac t erizat ion of ly mphadenopat hy by magnet ic resonanc e relaxat ion t imes: preliminary result s. Radiology 1985;155:691–697. 65. Dorf man RE, Alpern MB, Gross BH, et al. Upper abdominal ly mph nodes: c rit eria f or normal size det ermined w it h CT . Radiology 1991;180:319–322. 66. Dubenec SR, Whit e GH, Pasenau J, et al. Endot ension. A rev iew of c urrent v iew s on pat hophy siology and t reat ment . J Car diov asc Sur g (T or ino) 2003;44:553–557. 67. Ebner F , Kressel HY , Mint z MC, et al. T umor rec urrenc e v ersus f ibrosis in t he f emale pelv is: dif f erent iat ion w it h MR at 1.5 T . Radiology 1988;166:333–340. 68. Edelman RR. MR angiography : present and f ut ure. AJR Am J Roent genol 1993;161:1–11. 69. Eisenst at RS, Whit f ord AC, Lane MJ, et al. T he “ f lat c av a” sign rev isit ed: w hat is it s signif ic anc e in pat ient s w it hout t rauma? AJR Am J Roent genol 2002;178:21–25. P.1227 70. Engellau L, Olsrud J, Broc kst edt S, et al. MR ev aluat ion ex v iv o and in v iv o of a c ov ered st ent - graf t f or abdominal aort ic aneury sms: f erromagnet ism, heat ing, art if ac t s, and v eloc it y mapping. J Magn Reson Im aging 2000;12:112–121. 71. Erasmus JJ, Mc Adams HP, Pat z EF Jr, et al. Ev aluat ion of primary pulmonary c arc inoid t umors using F DG- PET . AJR Am J Roent genol 1998;170:1369–1373.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2634

17 - Retroperitoneum 72. Espirit u JD, Creer MH, Miklos AZ, et al. F at al t umor t hrombosis due t o an inf erior v ena c av a leiomy osarc oma in a pat ient w it h ant iphospholipid ant ibody sy ndrome. May o Clin Pr oc 2002;77: 595–599. 73. F arber A, Wagner WH, Cossman DV, et al. Isolat ed dissec t ion of t he abdominal aort a: c linic al present at ion and t herapeut ic opt ions. J Vasc Sur g 2002;36:205–210.

74. F arner MC, Carpent er JP, Baum RA, et al. Early c hanges in abdominal aort ic aneury sm diamet er af t er endov asc ular repair. J Vasc Int er v Radiol 2003;14:205–210. 75. F eig BW. Ret roperit oneal sarc omas. Sur g Onc ol Clin N Am 2003; 12:369–377. 76. F eldberg MAM, Koehler PR, v an Waes PF GM. Psoas c ompart ment disease st udied by c omput ed t omography . Radiology 1983; 148:505–512. 77. F illinger MF , Raghav an ML, Marra SP, et al. In v iv o analy sis of mec hanic al w all st ress and abdominal aort ic aneury sm rupt ure risk. J Vasc Sur g 2002;36:589–597. 78. F illinger MF , Marra SP, Raghav an ML, et al. Predic t ion of rupt ure risk in abdominal aort ic aneury sm during observ at ion: w all st ress v ersus diamet er. J Vasc Sur g 2003;37:724–732. 79. F illinger MF , Rac usin J, Baker RK, et al. Anat omic c harac t erist ic s of rupt ured abdominal aort ic aneury sm on c onv ent ional CT sc ans: implic at ions f or rupt ure risk. J Vasc Sur g 2004;39:1243–1252. 80. F rauenf elder T , Wildermut h S, Marinc ek B, et al. Nont raumat ic emergent abdominal v asc ular c ondit ions: adv ant ages of mult i- det ec t or row CT and t hree- dimensional imaging. Radiogr aphic s 2004;24:481–496. 81. F riedland GW, deVries PA, Nino- Murc ia M, et al. Congenit al anomalies of t he inf erior v ena c av a: embry ogenesis and MR f eat ures. Ur ol Radiol 1992;13:237–248. 82. F riedman AC, Hart man DS, Sherman J, et al. Comput ed t omography of abdominal f at t y masses. Radiology 1981;139:415–429. 83. Gaa J, Bohm C, Ric ht er A, et al. Aort oc av al f ist ula c omplic at ing abdominal aort ic aneury sm: diagnosis w it h gadolinium- enhanc ed t hree- dimensional MR angiography . Eur Radiol 1999;9:1438–1440. 84. Gale ME, Johnson WC, Gerzof SG, et al. Problems in CT diagnosis of rupt ured abdominal aort ic aneury sms. J Com put Assist T om ogr 1986;10:637–641.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2635

17 - Retroperitoneum 85. Ganaha F , Miller DC, Sugimot o K, et al. Prognosis of aort ic int ramural hemat oma w it h and w it hout penet rat ing at herosc lerot ic ulc er. A c linic al and radiologic al analy sis. Cir c ulat ion 2002;106:342–348.

86. Gat c ombe HG, Assikis V, Kooby D, et al. Primary ret roperit oneal t erat omas: a rev iew of t he lit erat ure. J Sur g Onc ol 2004;86:107–113. 87. Gay er G, Apt er S, Jonas T , et al. Poly splenia sy ndrome det ec t ed in adult hood: report of eight c ases and rev iew of t he lit erat ure. Abdom Im aging 1999;24:178–184. 88. Gay er G, Luboshit z J, Hert z M, et al. Congenit al anomalies of t he inf erior v ena c av a rev ealed on CT in pat ient s w it h deep v ein t hrombosis. AJR Am J Roent genol 2003;180:729–732. 89. Gay er G, Zissin R, St rauss S, et al. IVC anomalies and right renal aplasia det ec t ed on CT : a possible link? Abdom Im aging 2003;28: 395–399. 90. Glazer HS, Lee JKT , Lev it t RG, et al. Radiat ion f ibrosis: dif f erent iat ion f rom rec urrent t umor by MR imaging. Radiology 1985;156: 721–726. 91. Goldman SM, Dav idson AJ, Neal J. Ret roperit oneal and pelv ic hemangioperic y t omas: c linic al, radiologic , and pat hologic c orrelat ion. Radiology 1988;168:13–17. 92. Golzarian J, Dussaussois L, Abada HT , et al. Helic al CT of aort a af t er endoluminal st ent - graf t t herapy : v alue of biphasic ac quisit ion. AJR Am J Roent genol 1998;171:329–331. 93. Golzarian J, Murgo S, Dussaussois L, et al. Ev aluat ion of abdominal aort ic aneury sm af t er endoluminal t reat ment : c omparison of c olor Doppler sonography w it h biphasic helic al CT . AJR Am J Roent genol 2002;178:623–628. 94. Gomori JM, Grossman RI, Goldberg HI, et al. Int rac ranial hemat omas: imaging by high f ield MR. Radiology 1985;157:87–93. 95. Gordon BA, Mart inez S, Collins AJ. Py omy osit is: c harac t erist ic s at CT and MR imaging. Radiology 1995;197:279–286. 96. Gossios K, Argy ropoulou M, Akrit idis N. Unc ommon manif est at ions of ret roperit oneal f ibrosis. Clin Radiol 2003;58:331–333. 97. Goy en M, Ruehm SG, Debat in JF . MR- angiography : t he role of c ont rast agent s. Eur J Radiol 2000;34:247–256. 98. Great orex RA, Dixon AK, F low er CDR, et al. Limit at ions of c omput ed t omography in leaking abdominal aort ic aneury sms. BMJ 1988;23:284–285. 99. Grubnic S, Vinnic ombe SJ, Norman AR, et al. MR ev aluat ion of normal ret roperit oneal and pelv ic ly mph nodes. Clin Radiol 2002;57:193–200; disc ussion 201–194.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2636

17 - Retroperitoneum

100. Guermazi A, Bric e P, Hennequin C, et al. Ly mphography : an old t ec hnique ret ains it s usef ulness. Radiogr aphic s 2003;23:1541–1558; disc ussion 1559–1560. 101. Guinet C, Buy JN, Ghossain MA, et al. Aort ic anast omot ic pseudoaneury sms: US, CT , MR, and angiography . J Com put Assist T om ogr 1992;16:182–188. 102. Gupt a AK, Cohan RH, F ranc is IR. Pat t erns of rec urrent ret roperit oneal sarc omas. AJR Am J Roent genol 2000;174:1025–1030. 103. Haaga JR, Baldw in N, Reic h NE, et al. CT det ec t ion of inf ec t ed sy nt het ic graf t s: preliminary report of a new sign. AJR Am J Roent genol 1978;131:317–320. 104. Hagan PG, Nienaber CA, Isselbac her EM, et al. T he int ernat ional regist ry of ac ut e aort ic dissec t ion (IRAD). New insight s int o an old disease. JAMA 2000;283:897–903. 105. Hahn PF , Saini S, St ark DD, et al. Int raabdominal hemat oma: t he c onc ent ric - ring sign in MR imaging. AJR Am J Roent genol 1987;148:115–119. 106. Halliday KE, Al- Kut oubi A. Draped aort a: CT sign of c ont ained leak of aort ic aneury sms. Radiology 1996;199:41–43. 107. Hany T F , Debat in JF , Leung DA, et al. Ev aluat ion of t he aort oiliac and renal art eries: c omparison of breat h- hold, c ont rast - enhanc ed, t hreedimensional MR angiography w it h c onv ent ional c at het er angiography . Radiology 1997;204:357–362. 108. Harisinghani MG, Saini S, Weissleder R, et al. MR ly mphangiography using ult rasmall superparamagnet ic iron oxide in pat ient s w it h primary abdominal and pelv ic malignanc ies: radiographic - pat hologic c orrelat ion. AJR Am J Roent genol 1999;172: 1347–1351. 109. Harisinghani MG, Barent sz J, Hahn PF , et al. Noninv asiv e det ec t ion of c linic ally oc c ult ly mph- node met ast ases in prost at e c anc er. N Engl J Med 2003;348:2491–2498. 110. Harris JA, Bis KG, Glov er JL, et al. Penet rat ing at herosc lerot ic ulc ers of t he aort a. J Vasc Sur g 1994;19:90–99. 111. Hart man DS. Ret roperit oneal t umors and ly mphadenopat hy . Ur ol Radiol 1990;12:132–134. 112. Hart man DS, Hay es WS, Choy ke PL, et al. Leiomy osarc oma of t he ret roperit oneum and inf erior v ena c av a: radiologic - pat hologic c orrelat ion. Radiogr aphic s 1992;12:1203–1220.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2637

17 - Retroperitoneum 113. Hart nell GG. Imaging of aort ic aneury sms and dissec t ion: CT and MRI. J T hor ac Im aging 2001;16:35–46. 114. Hay asaka K, T anaka Y , Soeda S, et al. MR f indings in primary ret ropert ioneal sc hw annoma. Ac t a Radiol 1999;40:78–82. 115. Hay ashi H, Kumazaki T . Case report : inf lammat ory abdominal aort ic

aneury sm—dy namic Gd- DT PA enhanc ed magnet ic resonanc e imaging f eat ures. Br J Radiol 1995;68:321–323. 116. Hay ashi H, Mat suoka Y , Sakamot o I, et al. Penet rat ing at herosc lerot ic ulc er of t he aort a: imaging f eat ures and disease c onc ept . Radiogr aphic s 2000;20:995–1005. 117. Hay es WS, Dav idson AJ, Grimley PM, et al. Ext raadrenal ret roperit oneal paraganglioma: c linic al, pat hologic , and CT f indings. AJR Am J Roent genol 1990;155:1247–1250. 118. Heiberg E, Wolv erson MK, Saundaram M, et al. CT c harac t erist ic s of aort ic at herosc lerot ic aneury sm v ersus aort ic dissec t ion. J C omput Assist Tomogr 1985;9:78–83. 119. Hemant D, Krant ikumar R, Amit a J, et al. Primary leiomy osarc oma of inf erior v ena c av a, a rare ent it y : imaging f eat ures. Aust r alas Radiol 2001;45:448–451. 120. Herlinger H, Met z DC. Malabsorpt ion st at es. In: Herlinger H, Maglint e DDT , Birnbaum BA, eds. Clinic al im aging of t he sm all int est ine. New Y ork: Springer, 1999:344–345. P.1228 121. Hert s BR, Megibow AJ, Birnbaum BA, et al. High at t enuat ion ly mphadenopat hy in AIDS pat ient s: signif ic anc e of f indings at CT . Radiology 1992;185:777–781. 122. Hilt on S, Herr HW, T eit c her JB, et al. CT det ec t ion of ret roperit oneal ly mph node met ast ases in pat ient s w it h c linic al st age I t est ic ular nonseminomat ous germ c ell c anc er: assessment of size and dist ribut ion c rit eria. AJR Am J Roent genol 1997;169:521–525. 123. Hines J, Kat z DS, Gof f ner L, et al. F at c ollec t ion relat ed t o t he int rahepat ic inf erior v ena c av a on CT . AJR Am J Roent genol 1999;172: 409–411. 124. Hines OJ, Nelson S, Quinones- Baldric h WJ, et al. Leiomy osarc oma of t he inf erior v ena c av a: prognosis and c omparison w it h leiomy osarc oma of ot her anat omic sit es. Canc er 1999;85: 1077–1083.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2638

17 - Retroperitoneum 125. Hof f man M, Klet t er K, Diemling M, et al. Posit ron emission t omography w it h f luorine- 18- 2- f luoro- 2- deoxy - D- gluc ose (F 18- F DG) does not v isualize

ext ranodal B- c ell ly mphoma of t he muc osa assoc iat ed ly mphoid t issue (MALT )t y pe. Ann Onc ol 1999;10: 1185–1189. 126. Horejs D, Gilbert PM, Burst ein S, et al. Normal aort oiliac diamet ers by CT . J Com put Assist T om ogr 1988;12:602–603. 127. How at AJ, Mc Phie JL, Smit h DA, et al. Cav it at ion of mesent eric ly mph nodes: a rare c omplic at ion of c oeliac disease, assoc iat ed w it h a poor out c ome. Hist opat hology 1995;27:349–354. 128. Hric ak H, Amparo E, F isher MR, et al. Abdominal v enous sy st em: assessment using MR. Radiology 1985;156:415–422. 129. Hubsc h P, Sc huraw it zki H, Susani M, et al. Color Doppler imaging of inf erior v ena c av a: ident if ic at ion of t umor t hrombus. J Ult r asound Med 1992;11:639–645. 130. Hulnic k DH, Chat son GP, Megibow AJ, et al. Ret roperit oneal f ibrosis present ing as c olonic dy sf unc t ion: CT diagnosis. J Com put Assist T om ogr 1988;12:159–161. 131. Husband JE, Robinson L, T homas G. Cont rast enhanc ing ly mph nodes in bladder c anc er: a pot ent ial pit f all on CT . Clin Radiol 1992;45:395–398. 132. Iino M, Kuribay ashi S, Imakit a S, et al. Sensit iv it y and spec if ic it y of CT in t he diagnosis of inf lammat ory abdominal aort ic aneury sms. J Com put Assist T om ogr 2002;26:1006–1012. 133. Insko EK, Kulzer LM, F airman RM, et al. MR imaging f or t he det ec t ion of endoleaks in rec ipient s of abdominal aort ic st ent - graf t s w it h low magnet ic susc ept ibilit y . Ac ad Radiol 2003;10:509–513. 134. Israel GM, Bosniak MA, Sly w ot zky CM, et al. CT dif f erent iat ion of large exophy t ic renal angiomy olipomas and perirenal liposarc omas. AJR Am J Roent genol 2002;179:769–773. 135. Iy er R, Ef t ekhari F , Varma D, et al. Cy st ic ret roperit oneal ly mphangioma: CT , ult rasound and MR f indings. Pediat r Radiol 1993;23:305–306. 136. Jac oby WT , Cohan RH, Baker ME, et al. Ov arian v ein t hrombosis in onc ology pat ient s: CT det ec t ion and c linic al signif ic anc e. AJR Am J Roent genol 1990;155:291–294. 137. Jain KA, Jef f rey RB. Gonadal v ein t hrombosis in pat ient s w it h ac ut e gast roint est inal inf lammat ion. Radiology 1991;180:111–113. 138. Janzen NK, Laif er- Narin S, Han KR, et al. Emerging t ec hnologies in uroradiologic imaging. Ur ol Onc ol 2003;21:317–326.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2639

17 - Retroperitoneum

139. Jef f rey RBJ, F ederle MP. T he c ollapsed inf erior v ena c av a: CT ev idenc e of hy pov olemia. AJR Am J Roent genol 1988;150:431–432. 140. Jef f rey RBJ, Cardoza JD, Olc ot t EW. Det ec t ion of ac t iv e int raabdominal art erial hemorrhage: v alue of dy namic c ont rast - enhanc ed CT . AJR Am J Roent genol 1991;156:725–729. 141. Jerusalem G, Beguin Y , Najjar F , et al. Posit ron emission t omography (PET ) w it h 18F - f luorodeoxy gluc ose (18F - F DG) f or t he st aging of low - grade non- Hodgkin's ly mphoma. Ann Onc ol 2001; 12:825–830. 142. Joarder R, Gedroy c WM. Magnet ic resonanc e angiography : t he st at e of t he art . Eur Radiol 2001;11:446–453. 143. Joels CS, Sing RF , Henif ord BT . Complic at ions of inf erior v ena c av a f ilt ers. Am Sur g 2003;69:654–659. 144. Johnson KK, Russ PD, Bair JH, et al. Diagnosis of sy nt het ic v asc ular graf t inf ec t ion: c omparison of CT and gallium sc ans. AJR Am J Roent genol 1990;154:405–409. 145. Jung G, Heindel W, v on Bergw elt - Baildon M, et al. Abdominal ly mphoma st aging: is MR imaging w it h T 2- w eight ed t urbo- spin- ec ho sequenc e a diagnost ic alt ernat iv e t o c ont rast - enhanc ed spiral CT ? J Com put Assist T om ogr 2000;24:783–787. 146. Just ic h E, Amparo EG, Hric ak H, et al. Inf ec t ed aort oiliof emoral graf t s: magnet ic resonanc e imaging. Radiology 1985;154:133–136. 147. Kallman DA, King BF , Hat t ery RR, et al. Renal v ein and inf erior v ena c av a t umor t hrombus in renal c ell c arc inoma: CT , US, MRI and v enac av ography . J Com put Assist T om ogr 1992;16:240–247. 148. Kalman PG, Johnst on KW. Abdominal aort ic aneury sms. In: Hobson RW 2nd, Wilson SE, Veit h F J, eds. Vasc ular sur ger y pr inc iples and pr ac t ic e, 3rd ed., rev ised and expanded. New Y ork: Marc el Dekker, 2004:631–640. 149. Kam J, Pat el S, Ward RE. Comput ed t omography of aort ic and aort oiliof emoral graf t s. J Com put Assist T om ogr 1982;6:298–303. 150. Kaneko T , T akahashi S, T akeuc hi T , et al. Cast leman's disease in t he ret roperit oneal spac e. J Ur ol 2003;169:265–266. 151. Kazerooni EA, Bree RL, Williams DM. Penet rat ing at herosc lerot ic ulc ers of t he desc ending t horac ic aort a: ev aluat ion w it h CT and dist inc t ion f rom aort ic dissec t ion. Radiology 1992;183:759–765. 152. Kenney PJ, Wagner BJ, Rao P, et al. My elolipoma: CT and pat hologic f eat ures. Radiology 1998;208:87–95.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2640

17 - Retroperitoneum 153. Kerst ing- Sommerhof f BA, Higgins DB, Whit e RD, et al. Aort ic dissec t ion: sensit iv it y and spec if ic it y of MR imaging. Radiology 1988;174:727–731. 154. Kim D, Edelman RR, Kent KC, et al. Abdominal aort a and renal art ery st enosis: ev aluat ion w it h MR angiography . Radiology 1990;174:727–731. 155. Kim SH, Choi BI, Han MC, et al. Ret roperit oneal neurilemoma: CT and MR f indings. AJR Am J Roent genol 1992;159:1023–1026. 156. Kim T , Murakami T , Oi H, et al. CT and MR imaging of abdominal liposarc oma. AJR Am J Roent genol 1996;166:829–833. 157. Kim T K, Chung JW, Han JK, et al. Hepat ic c hanges in benign obst ruc t ion of t he hepat ic inf erior v ena c av a: CT f indings. AJR Am J Roent genol 1999;173:1235–1242. 158. Kinney T B. Updat e on inf erior v ena c av a f ilt ers. J Vasc Int er v Radiol 2003;14:425–440. 159. Kissin EY , Merkel PA. Diagnost ic imaging in T akay asu art erit is. Cur r Opin Rheum at ol 2004;16:31–37. 160. Klein F A, Whit more WF Jr, Sogani PC, et al. Inguinal ly mph node met ast asis f rom germ c ell t est ic ular t umors. J Ur ol 1984;131: 497–500. 161. Ko SF , Wan Y L, Lee T Y , et al. CT f eat ures of c alc if ic at ions in abdominal malignant f ibrous hist ioc y t oma. Clin Im aging 1998;22: 408–413. 162. Kobay ashi A, Mat sui O, T akashima T , et al. Calc if ic at ion in c av al

membrane c ausing primary Budd- Chiari sy ndrome: CT demonst rat ion. J Com put Assist T om ogr 1988;12:401–404. 163. Korobkin M, Callen PW, F isc h AE. Comput ed t omography of t he pelv is and ret roperit oneum. Radiol Clin Nor t h Am 1979;17: 301–318. 164. Korobkin M, Silv erman PM, Quint LE, et al. CT of t he ext raperit oneal spac e: normal anat omy and f luid c ollec t ions. AJR Am J Roent genol 1992;159:933–942. 165. Kost akoglu L, Agress H Jr, Goldsmit h SJ. Clinic al role of F DG- PET in ev aluat ion of c anc er pat ient s. Radiogr aphic s 2003;23:315–340. 166. Kot t ra JJ, Dunnic k NR. Ret roperit oneal f ibrosis. Radiol Clin Nor t h Am 1996;34:1259–1275. 167. Kramer CM, Cerilli LA, Hagspiel K, et al. Magnet ic resonanc e imaging ident if ies t he f ibrous c ap in at herosc lerot ic abdominal aort ic aneury sm. Cir c ulat ion 2004;109:1016–1021. 168. Krinsky G, Johnson G, Rof sky N, et al. Venous aneury sms: MR diagnosis w it h t he “ lay ered gadolinium” sign. J Com put Assist T om ogr 1997;21:623–627.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2641

17 - Retroperitoneum 169. Kroepil P, Coakley F V, Graser A, et al. Appearanc e and dist inguishing f eat ures of ret roperit oneal c alc if ic at ions at c omput ed t omography . J Com put Assist T om ogr 2003;27:860–863. 170. Kulay lat MN, Karakousis CP, Doerr RJ, et al. Leiomy osarc oma of t he inf erior v ena c av a: a c linic opat hologic rev iew and report of t hree c ases. J Sur g Onc ol 1997;65:205–217. 171. Kurosaki Y , T anaka Y O, It ai Y . Well- dif f erent iat ed liposarc oma of t he

ret roperit oneum w it h a f at - f luid lev el: US, CT , and MR appearanc e. Eur Radiol 1998;8:474–475. 172. Kurugoglu S, Ogut G, Mihmanli I, et al. Abdominal leiomy osarc omas: radiologic appearanc es at v arious loc at ions. Eur Radiol 2002;12:2933–2942. 173. Kv ilekv al KHV, Best IM, Mason RA, et al. T he v alue of c omput ed t omography in t he management of sy mpt omat ic abdominal aort ic aneury sms. J Vasc Sur g 1990;12:28–33. P.1229 174. Landay MJ, Virolainen H. “ Hy perdense” aort ic w all: pot ent ial pit f all in CT sc reening f or aort ic dissec t ion. J Com put Assist T om ogr 1991;15:561–564. 175. Lane RH, St ephens DH, Reiman HM. Primary ret roperit oneal neoplasms: CT f indings in 90 c ases w it h c linic al and pat hologic c orrelat ion. AJR Am J Roent genol 1989;152:83–89. 176. Lat if i HR, Heiken JP. CT of inf lammat ory abdominal aort ic aneury sm: dev elopment f rom an unc omplic at ed at herosc lerot ic aneury sm. J Com put Assist T om ogr 1992;16:484–486. 177. Lederle F A, Johnson GR, Wilson SE, et al. Prev alenc e and assoc iat ions of abdominal aort ic aneury sm det ec t ed t hrough sc reening. Ann Int er n Med 1997;126:441–449. 178. Lee JKT , St anley RJ, Sagel SS, et al. Ac c urac y of CT in det ec t ing int raabdominal and pelv ic ly mph node met ast ases f rom pelv ic c anc ers. AJR Am J Roent genol 1978;131:675–679. 179. Lee JKT , Heiken JP, Ling D, et al. Magnet ic resonanc e imaging of abdominal and pelv ic ly mphadenopat hy . Radiology 1984;153: 181–188. 180. Lee JKT , Glazer HS. Psoas musc le disorders: MR imaging. Radiology 1986;160:683–687. 181. Lenc hik L, Dov gan DJ, Kier R. CT of t he iliopsoas c ompart ment : v alue in dif f erent iat ing t umor, absc ess, and hemat oma. AJR Am J Roent genol 1994;162:83–86.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2642

17 - Retroperitoneum 182. LePage MA, Quint LE, Sonnad SS, et al. Aort ic dissec t ion: CT f eat ures t hat dist inguish t rue lumen f rom f alse lumen. AJR Am J Roent genol 2001;177:207–211. 183. Lev y AD, Cant isani V, Miet t inen M. Abdominal ly mphangiomas: imaging f eat ures w it h pat hologic c orrelat ion. AJR Am J Roent genol 2004;182:1485–1491. 184. Lew is E, Bernardino ME, Salv ador PG, et al. Post - t herapy CT det ec t ed mass in ly mphoma pat ient s: is it v iable t issue? J Com put Assist T om ogr 1982;6:792–795. 185. Lew is JJ, Leung D, Woodruf f JM, et al. Ret roperit oneal sof t - t issue

sarc oma: analy sis of 500 pat ient s t reat ed and f ollow ed at a single inst it ut ion. Ann Sur g 1998;228:355–365. 186. Li DKB, Rennie CS. Abdominal c omput ed t omography in Whipple's disease. J Com put Assist T om ogr 1981;5:249–252. 187. Libshit z HI, Jing BS, Wallac e S, et al. St erilized met ast ases: a diagnost ic and t herapeut ic dilemma. AJR Am J Roent genol 1983;140: 15–19. 188. Lim JH, Park JH, Auh Y H. Membranous obst ruc t ion of t he inf erior v ena c av a: c omparison of f indings at sonography , CT , and v enography . AJR Am J Roent genol 1992;159:515–520. 189. Lim JH, Kim B, Auh Y H. Anat omic al c ommunic at ions of t he perirenal spac e. Br J Radiol 1998;71:450–456. 190. Limet R, Sakalihassan N, Albert A. Det erminat ion of t he expansion rat e and inc idenc e of rupt ure of abdominal aort ic aneury sm. J Vasc Sur g 1991;14:540–548. 191. Lipson E, Polliak A, Bloom RA. Value of ly mphangiography in t he st aging of Hodgkin ly mphoma. Radiology 1994;193:757–759. 192. Loc hbuehler H, Weber H, Mehlig U, et al. Aneury sm of t he inf erior v ena c av a in a 5- y ear- old boy . J Pediat r Sur g 2002;37:E10. 193. Lookst ein RA, Goldman J, Pukin L, et al. T ime- resolv ed magnet ic resonanc e angiography as a noninv asiv e met hod t o c harac t erize endoleaks: init ial result s c ompared w it h c onv ent ional angiography . J Vasc Sur g 2004;39:27–33. 194. Loud PA, Grossman ZD, Klippenst ein DL, et al. Combined CT v enography and pulmonary angiography : a new diagnost ic t ec hnique f or suspec t ed t hromboembolic disease. AJR Am J Roent genol 1998;170:951–954. 195. Low RN, Wall SD, Jef f rey RB, et al. Aort oent eric f ist ula and perigraf t inf ec t ion: ev aluat ion w it h CT . Radiology 1990;175:157–162.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2643

17 - Retroperitoneum 196. Mac edo T A, St anson AW, Oderic h GS, et al. Inf ec t ed aort ic aneury sms: imaging f indings. Radiology 2004;231:250–257. 197. Mac ura KJ, Corl F M, F ishman EK, et al. Pat hogenesis in ac ut e aort ic sy ndromes: aort ic dissec t ion, int ramural hemat oma, and penet rat ing at herosc lerot ic aort ic ulc er. AJR Am J Roent genol 2003;181:309–316.

198. Mac ura KJ, Szarf G, F ishman EK, et al. Role of c omput ed t omography and magnet ic resonanc e imaging in assessment of ac ut e aort ic sy ndromes. Sem in Ult r asound CT MR 2003;24:232–254. 199. Magnusson A, Andersson T , Larsson B, et al. Cont rast enhanc ement of pat hologic ly mph nodes demonst rat ed by c omput ed t omography . Ac t a Radiol 1989;30:307–310. 200. Maher MM, Mc Namara AM, Mac Eneaney PM, et al. Abdominal aort ic aneury sms: elec t iv e endov asc ular repair v ersus c onv ent ional surgery —ev aluat ion w it h ev idenc e- based medic ine t ec hniques. Radiology 2003;228:647–658. 201. Mant ello MT , Panac c ione JL, Moriart y PE, et al. Impending rupt ure of nonaneury smal bac t erial aort it is: CT diagnosis. J Com put Assist T om ogr 1990;14:950–953. 202. Marst on WA, Ahlquist R, Johnson G, et al. Misdiagnosis of rupt ured abdominal aort ic aneury sms. J Vasc Sur g 1992;152:133–136. 203. Mat hew s R, Smit h PA, F ishman EK, et al. Anomalies of t he inf erior v ena c av a and renal v eins: embry ologic and surgic al c onsiderat ions. Ur ology 1999;53:873–880. 204. Mat sunaga N, Hay ashi K, Sakamot o I, et al. T akay asu art erit is: prot ean radiologic manif est at ions and diagnosis. Radiogr aphic s 1997;17:579–594. 205. Mat sunaga N, Hay ashi K, Okada M, et al. Magnet ic resonanc e imaging f eat ures of aort ic diseases. T op Magn Reson Im aging 2003;14:253–266. 206. Mauro M. T he query c orner. Inf lammat ory aort ic aneury sms. Abdom Im aging 1997;22:357–358. 207. May o J, Gray R, St . Louis E, et al. Anomalies of t he inf erior v ena c av a. AJR Am J Roent genol 1983;140:339–345. 208. Mehard WB, Heiken JP, Sic ard GA. High- at t enuat ion c resc ent in abdominal aort ic aneury sm w all at CT : sign of ac ut e or impending rupt ure. Radiology 1994;192:359–362a(abst ). 209. Mey ers MA. T he ext raperit oneal spac es: normal and pat hologic anat omy . In: Mey ers MA, ed. Dy nam ic r adiology of t he abdom en, 5t h ed. New Y ork: Springer, 2000:333–477.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2644

17 - Retroperitoneum 210. Miller CL, Wec hsler RJ. CT ev aluat ion of Kimray - Greenf ield f ilt er c omplic at ions. AJR Am J Roent genol 1986;147:45–50.

211. Mindell HJ, Mast romat t eo JF , Dic key KW, et al. Anat omic c ommunic at ions bet w een t he t hree ret roperit oneal spac es: det erminat ion by CT - guided injec t ions of c ont rast mat erial in c adav ers. AJR Am J Roent genol 1995;164:1173–1178. 212. Mingoli A, Cav allaro A, Sapienza P, et al. Int ernat ional regist ry of inf erior v ena c av a leiomy osarc oma: analy sis of a w orld series on 218 pat ient s. Ant ic anc er Res 1996;16:3201–3206. 213. Minnit i S, Visent ini S, Proc ac c i C. Congenit al anomalies of t he v enae c av ae: embry ologic al origin, imaging f eat ures and report of t hree new v ariant s. Eur Radiol 2002;12:2040–2055. 214. Miy ake H, Suzuki K, Ueda S, et al. Loc alized f at c ollec t ion adjac ent t o t he int rahepat ic port ion of t he inf erior v ena c av a: a normal v ariant on CT . AJR Am J Roent genol 1992;158:423–425. 215. Miy azat o M, Y onou H, Sugay a K, et al. T ransit ional c ell c arc inoma of t he renal pelv is f orming t umor t hrombus in t he v ena c av a. Int J Ur ol 2001;8:575–577. 216. Molment i EP, Balf e DM, Kant erman RY , et al. Anat omy of t he ret roperit oneum: observ at ions of t he dist ribut ion of pat hologic f luid c ollec t ions. Radiology 1996;200:95–103. 217. Moore WS, Kashy ap VS, Vesc era CL, et al. Abdominal aort ic aneury sm: a 6- y ear c omparison of endov asc ular v ersus t ransabdominal repair. Ann Sur g 1999;230:298–308. 218. Mori H, F ukuda T , Isomot o I, et al. CT diagnosis of c at het er- induc ed sept ic t hrombus of v ena c av a. J Com put Assist T om ogr 1990;14:236–238. 219. Moriy ama Y , Y amamot o H, Hisat omi K, et al. Penet rat ing at herosc lerot ic ulc ers in an abdominal aort ic aneury sm: report of a c ase. Sur g T oday 1998;28:105–107. 220. Mukherjee JJ, Pepperc orn PD, Reznek RH, et al. Pheoc hromoc y t oma: ef f ec t of nonionic c ont rast medium in CT on c irc ulat ing c at ec holamine lev els. Radiology 1997;202:227–231. 221. Muller BT , Wegener OR, Grabit z K, et al. My c ot ic aneury sms of t he t horac ic and abdominal aort a and iliac art eries: experienc e w it h anat omic and ext ra- anat omic repair in 33 c ases. J Vasc Sur g 2001;33:106–113.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2645

17 - Retroperitoneum 222. Mulligan SA, Holley HC, Koehler RE, et al. CT and MR imaging in t he ev aluat ion of ret roperit oneal f ibrosis. J Com put Assist T om ogr 1989;13:277–281. 223. Munec hika H, Cohan RH, Baker ME, et al. Hemiazy gos c ont inuat ion of a lef t inf erior v ena c av a: CT appearanc e. J Com put Assist T om ogr 1988;12:328–330. 224. Munk PL, Sallomi DF , Janzen DL, et al. Malignant f ibrous hist ioc y t oma of sof t t issue imaging w it h emphasis on MRI. J Com put Assist T om ogr 1998;22:819–826. P.1230 225. Nesc his DG, Velazquez OC, Baum RA, et al. T he role of magnet ic resonanc e angiography f or endoprost het ic design. J Vasc Sur g 2001;33:488–494.

226. Nic hols CR, F ox EP. Ext ragonadal and pediat ric germ c ell t umors. Hem at ol Onc ol Clin Nor t h Am 1991;5:1189–1209. 227. Nishino M, Hay akaw a K, Minami M, et al. Primary ret roperit oneal neoplasms: CT and MR imaging f indings w it h anat omic and pat hologic diagnost ic c lues. Radiogr aphic s 2003;23:45–57. 228. Nit ec ki SS, Hallet JW Jr, St anson AW, et al. Inf lammat ory abdominal aort ic aneury sms: a c ase- c ont rol st udy . J Vasc Sur g 1996; 23:860–869. 229. O'Dohert y MJ, Mac donald EA, Barringt on SF , et al. Posit ron emission t omography in t he management of ly mphomas. Clin Onc ol (R Coll Radiol) 2002;14:415–426. 230. Obernost erer A, Asc hauer M, Sc hnedl W, et al. Anomalies of t he inf erior v ena c av a in pat ient s w it h iliac v enous t hrombosis. Ann Int er n Med 2002;136:37–41. 231. Oderic h GS, Pannet on JM, Bow er T C, et al. Inf ec t ed aort ic aneury sms: aggressiv e present at ion, c omplic at ed early out c ome, but durable result s. J Vasc Sur g 2001;34:900–908. 232. Ohara PJ, Borkow shi GP, Hert zer NR, et al. Nat ural hist ory of periprost het ic air on c omput erized axial t omographic examinat ion of t he abdomen f ollow ing abdominal aort ic aneury sm repair. J Vasc Sur g 1984;1:429–433. 233. Ohki T , Lipsit z EC, Veit h F J. Endov asc ular graf t s f or aneury sms, oc c lusiv e disease, and v asc ular injuries. In: Hobson RW 2nd, Wilson SE, Veit h F J, eds. Vasc ular sur ger y pr inc iples and pr ac t ic e, 3rd ed., rev ised and expanded. New Y ork: Marc el Dekker, 2004: 363–393.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2646

17 - Retroperitoneum 234. Okuda K. Membranous obst ruc t ion of t he inf erior v ena c av a (oblit erat iv e hepat oc av opat hy , Okuda). J Gast r oent er ol Hepat ol 2001;16:1179–1183. 235. Okuda K. Inf erior v ena c av a t hrombosis at it s hepat ic port ion (oblit erat iv e hepat oc av opat hy ). Sem in Liv er Dis 2002;22:15–26. 236. Ort on DF , LeVeen RF , Saigh JA, et al. Aort ic prost het ic graf t inf ec t ions: radiologic manif est at ions and implic at ions f or management . Radiogr aphic s 2000;20:977–993. 237. Pagani JJ, T homas JL, Bernardino ME. Comput ed t omographic manif est at ions of abdominal and pelv ic v enous c ollat erals. Ra diology 1982;142:415–419. 238. Panic ek DM, T onger GC, Heelan RT , et al. Nonseminomat ous germ c ell t umors: enlarging masses despit e c hemot herapy . Radiology 1990;175:499–502.

239. Papanic olaou N, Wit t enberg J, F erruc c i JT J, et al. Preoperat iv e ev aluat ion of abdominal aort ic aneury sms by c omput ed t omography . AJR Am J Roent genol 1986;146:711–715. 240. Papanic olaou N, Y oder IC, Lee MJ. Primary ret roperit oneal neoplasms: how c lose c an w e c ome in making t he c orrec t diagnosis? Ur ol Radiol 1992;14:221–228. 241. Park BK, Kim SH, Moon MH. Idiopat hic presac ral ret roperit oneal f ibrosis: report of t w o c ases. Br J Radiol 2003;76:570–573. 242. Parodi JC, Palmaz JC, Barone HD. T ransf emoral int raluminal graf t implant at ion f or abdominal aort ic aneury sms. Ann Vasc Sur g 1991;5:491–499. 243. Parra JR, Lee C, Hodgson KJ, et al. Endograf t inf ec t ion leading t o rupt ure of aort ic aneury sm. J Vasc Sur g 2004;39:676–678. 244. Part ic ipant s T UKSAT . Long- t erm out c omes of immediat e repair c ompared w it h surv eillanc e of small abdominal aort ic aneury sms. N Engl J Med 2002;346:1445–1452. 245. Pereles F S, Mc Cart hy RM, Baskaran V, et al. T horac ic aort ic dissec t ion and aneury sm: ev aluat ion w it h nonenhanc ed t rue F ISP MR angiography in less t han 4 minut es. Radiology 2002;223: 270–274. 246. Pienkny AJ, Hert s B, St reem SB. Cont emporary diagnosis of ret roc av al uret er. J Endour ol 1999;13:721–722. 247. Pierro JA, Soleimanpour M, Bory JL. Lef t ret roc av al uret er assoc iat ed w it h lef t inf erior v ena c av a. AJR Am J Roent genol 1990;155: 545–546.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2647

17 - Retroperitoneum 248. Pist olese GR, Ippolit i A, Mauriello A, et al. Post operat iv e regression of ret roperit oneal f ibrosis in pat ient s w it h inf lammat ory abdominal aort ic aneury sms: ev aluat ion w it h spiral c omput ed t omography . Ann Vasc Sur g 2002;16:201–209.

249. Plat t JF , Ellis JH, Korobkin M, et al. Pot ent ial renal donors: c omparison of c onv ent ional imaging w it h helic al CT . Radiology 1996;198:419–423. 250. Pode D, Caine M. Spont aneous ret roperit oneal hemorrhage. J Ur ol 1992;147:311–318. 251. Pombo F , Rodriquez E, Mat o J, et al. Pat t erns of c ont rast enhanc ement of t uberc ulous ly mph nodes demonst rat ed by c omput ed t omography . Clin Radiol 1992;46:13–17. 252. Pombo F , Rodriquez E, Carunc ho MV, et al. CT at t enuat ion v alues and enhanc ing c harac t erist ic s of t horac oabdominal ly mphomat ous adenopat hies. J Com put Assist T om ogr 1994;18:59–62. 253. Pow ell JT , Greenhalgh RM. Small abdominal aort ic aneury sms. N Engl J Med 2003;348:1895–1901. 254. Princ e MR, Narasimham DL, St anley JC, et al. Breat h- hold gadoliniumenhanc ed MR angiography of t he abdominal aort a and it s major branc hes. Radiology 1995;197:785–792. 255. Puv anesw ary M, Cuganesan R. Det ec t ion of aort oent eric f ist ula w it h helic al CT . Aust r alas Radiol 2003;47:67–69. 256. Quanadli SD, Mesurolle B, Coggia M, et al. Abdominal aort ic aneury sm: pret herapy assessment w it h dual- slic e helic al CT angiography . AJR Am J Roent genol 2000;174:181–187. 257. Qv arf ordt PG, Reilly LM, Mark AS, et al. Comput erized t omographic assessment of graf t inc orporat ion af t er aort ic rec onst ruc t ion. Am J Sur g 1985;150:227–231. 258. Radin DR. Disseminat ed hist oplasmosis: abdominal CT f indings in 16 pat ient s. AJR Am J Roent genol 1991;157:955–958. 259. Radin DR. Int raabdominal My c obac t er ium t uber c ulosis v s My c obac t er ium av ium -int r ac ellular e inf ec t ions in pat ient s w it h AIDS: dist inc t ion based on CT f indings. AJR Am J Roent genol 1991;156: 487–491. 260. Radin R, Dav id CL, Goldf arb H, et al. Adrenal and ext ra- adrenal ret roperit oneal ganglioneuroma: imaging f indings in 13 adult s. Radiology 1997;202:703–707. 261. Rahmouni A, T empany C, Jones R, et al. Ly mphoma: monit oring t umor size and signal int ensit y w it h MR imaging. Radiology 1993;188:445–451.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2648

17 - Retroperitoneum 262. Raju NL, Aust in JH. Case 37: juxt ac av al f at c ollec t ion—mimic of lipoma in t he subdiaphragmat ic inf erior v ena c av a. Radiology 2001;220:471–474. 263. Raman KG, Missig- Carroll N, Ric hardson T , et al. Color- f low duplex ult rasound sc an v ersus c omput ed t omographic sc an in t he surv eillanc e of endov asc ular aneury sm repair. J Vasc Sur g 2003;38: 645–651. 264. Rankin SC. Assessment of response t o t herapy using c onv ent ional imaging. Eur J Nuc l Med Mol Im aging 2003;30[suppl 1]: S56–S64. 265. Rapt opolous V, T ouliopoulos P, Lei QF , et al. Medial border of t he

perirenal spac e: CT and anat omic c orrelat ion. Radiology 1997;205:777–784. 266. Rasmussen T E, Hallet t JW Jr. Inf lammat ory aort ic aneury sms: a c linic al rev iew w it h new perspec t iv es in pat hogenesis. Ann Sur g 1997;225:155–164. 267. Ray B, Hajdu SI, Whit more WF . Dist ribut ion of ret roperit oneal ly mph node met ast ases in t est ic ular germinal t umors. Canc er 1974;33:340–348. 268. Ray CE Jr, Kauf man JA. Complic at ions of inf erior v ena c av a f ilt ers. Abdom Im aging 1996;21:368–374. 269. Rebner M, Gross BH, Korobkin M, et al. CT appearanc e of right gonadal v ein. J Com put Assist T om ogr 1989;13:460–462. 270. Rehn SM, Ny man RS, Glimelius BLG, et al. Non- Hodgkin ly mphoma: predic t ing prognost ic grade w it h MR imaging. Radiology 1990;176:249–253. 271. Rehn SM, Sperber GO, Ny man RS, et al. Quant if ic at ion of inhomogeneit ies in malignanc y grading of non- Hodgkin ly mphoma w it h MR imaging. Ac t a Radiol 1993;34:3–9. 272. Reske SN. PET and rest aging of malignant ly mphoma inc luding residual masses and relapse. Eur J Nuc l Med Mol Im aging 2003; 30[suppl 1]:S82–S88. 273. Rha SE, By un JY , Jung SE, et al. Neurogenic t umors in t he abdomen: t umor t y pes and imaging c harac t erist ic s. Radiogr aphic s 2003;23:29–43. 274. Rhee RY , Glov ic zki P, Lut hra HS, et al. Ilioc av al c omplic at ions of ret roperit oneal f ibrosis. Am J Sur g 1994;168:179–183. 275. Rodriguez M. Comput ed t omography , magnet ic resonanc e imaging, and posit ron emission t omography in non Hodgkin's ly mphoma. Ac t a Radiol 1998;417:1–36. 276. Ros PR, Viamont e M Jr, Ry w lin AM. Malignant f ibrous hist ioc y t oma: mesenc hy mal t umor of ubiquit ous origin. AJR Am J Roent genol 1984;142:753–759. P.1231

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2649

17 - Retroperitoneum 277. Rosai J. Ly mph nodes. In: Rosai J, ed. Rosai and Ac ker m an's sur gic al pat hology . New Y ork: Mosby , 2004:1917–1961. 278. Rosai J. Perit oneum, ret roperit oneum and relat ed st ruc t ures. In: Rosai J, ed. Rosai and Ac ker m an's sur gic al pat hology . New Y ork: Mosby , 2004:2373–2415. 279. Rosai J. Male reproduc t iv e sy st em: t est is. In: Rosai J, ed. Rosai and Ac ker m an's sur gic al pat hology . New Y ork: Mosby , 2004:1412–1456.

280. Roy al SA, Callen PW. CT ev aluat ion of anomalies of t he inf erior v ena c av a and lef t renal v ein. J Com put Assist T om ogr 1979;15: 690–693. 281. Rozenblit AM, Pat las M, Rosenbaum AT , et al. Det ec t ion of endoleaks af t er endov asc ular repair of abdominal aort ic aneury sm: v alue of unenhanc ed and delay ed helic al CT ac quisit ions. Radiology 2003;227:426–433. 282. Rubenst ein WA, Gray G, Auh Y H, et al. CT of f ibrous t issues and t umors w it h sonographic c orrelat ion. AJR Am J Roent genol 1986; 147:1067–1074. 283. Rubin GD, Drake MD, Napel S, et al. Spiral CT of renal art ery st enosis: c omparison of t hree- dimensional rendering t ec hniques. Radiology 1994;190:181–189. 284. Rubin JI, Gomori JM, Grossman RI, et al. High- f ield MR imaging of ext ac ranial hemat omas. AJR Am J Roent genol 1987;148:813–817. 285. Ry an MF , At ri M. F at c ollec t ion relat ed t o t he int rahepat ic port ion of t he inf erior v ena c av a. AJR Am J Roent genol 2001;177: 251–252. 286. Ry dberg JN, Sudakof f GS, Hellman RS, et al. Posit ron emission t omography - c omput ed t omography imaging c harac t erist ic s of an inf erior v ena c av a t umor t hrombus w it h magnet ic resonanc e imaging c orrelat ion. J Com put Assist T om ogr 2004; 28:517–519. 287. Sant aella RO, F ishman EK, Lipset t PA. Primary v s sec ondary iliopsoas absc ess. Present at ion, mic robiology , and t reat ment . Ar c h Sur g 1995;130:1309–1313. 288. Sav ader SJ, Ot ero RR, Sav ader BL. Puerperal ov arian v ein t hrombosis: ev aluat ion w it h CT , US, and MR imaging. Radiology 1988;167:637–639. 289. Sc at arige JC, F ishman EK, Kuhajda F P, et al. Low at t enuat ion nodal met ast asis in t est ic ular c arc inoma. J Com put Assist T om ogr 1983;9:463–465. 290. Sc hoellnast H, T illic h M, Deut sc hmann HA, et al. Abdominal mult idet ec t or row c omput ed t omography : reduc t ion of c ost and c ont rast mat erial dose using saline f lush. J Com put Assist T om ogr 2003;27:847–853.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2650

17 - Retroperitoneum 291. Sebast ia C, Pallisa E, Quiroga S, et al. Aort ic dissec t ion: diagnosis and f ollow - up w it h helic al CT . Radiogr aphic s 1999;19:45–60. 292. Shet h R, Hanc hat e V, Rat hod K, et al. Aneury sms of t he inf erior v ena c av a. Aust r alas Radiol 2003;47:94–96. 293. Shin MS, Berland LL, Ho KJ. Small aort a: CT det ec t ion and c linic al signif ic anc e. J Com put Assist T om ogr 1990;14:102–103. 294. Shindo S, Kubot a K, Kojima A, et al. Anomalies of inf erior v ena c av a and lef t renal v ein: risks in aort ic surgery . Ann Vasc Sur g 2000;14:393–396. 295. Siegel CL, Cohan RH. CT of abdominal aort ic aneury sms. AJR Am J Roent genol 1994;163:17–29.

296. Siegel CL, Cohan RH, Korobkin M. Abdominal aort ic aneury sm morphology : CT f eat ures in pat ient s w it h rupt ured and nonrupt ured aneury sms. AJR Am J Roent genol 1994;163:1123–1129. 297. Singh K, Bonaa KH, Jac obsen BK, et al. Prev alenc e of and risk f ac t ors f or abdominal aort ic aneury sms in a populat ion- based st udy : t he T romso st udy . Am J Epidem iol 2001;154::236–244. 298. Singh K, Jac obsen BK, Solberg S, et al. Int ra- and int erobserv er v ariabilit y in t he measurement s of abdominal aort ic and c ommon iliac art ery diamet er w it h c omput ed t omography . T he T romso st udy . Eur J Vasc Endov asc Sur g 2003;25:399–407. 299. Siv it CJ, T ay lor GA, Bulas DI, et al. Post t raumat ic shoc k in c hildren: CT f indings assoc iat ed w it h hemody namic inst abilit y . Radiology 1992;182:723–726. 300. Solberg A, Angelsen A, Bergan U, et al. F requenc y of ly mphoc eles af t er open and laparosc opic pelv ic ly mph node dissec t ion in pat ient s w it h prost at e c anc er. Sc and J Ur ol Nephr ol 2003;37: 218–221. 301. Soler R, Rodriguez E, Lopez MF , et al. MR imaging in inf erior v ena c av a t hrombosis. Eur J Radiol 1995;19:101–107. 302. Sommer T , F ehske W, Holzknec ht N, et al. Aort ic dissec t ion: a c omparat iv e st udy of diagnosis w it h spiral CT , mult iplanar t ransesophageal ec hoc ardiography , and MR imaging. Radiology 1996;199:347–352. 303. Spit t ell PC, Spit t ell JA, Joy c e JW, et al. Clinic al f eat ures and dif f erent ial diagnosis of aort ic dissec t ion: experienc e w it h 236 c ases (1980–1990). May o Clin Pr oc 1993;68:642–651. 304. Sprit zer CE, Norc onk JJ Jr, Sost man HD, et al. Det ec t ion of deep v enous t hrombosis by magnet ic resonanc e imaging. Chest 1993;104:54–60.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2651

17 - Retroperitoneum 305. St ella A, Gargiulo M, F aggioli GL, et al. Post operat iv e c ourse of inf lammat ory abdominal aort ic aneury sms. Ann Vasc Sur g 1993; 7:229–238. 306. St omper PC, F ung CY , Soc inski MA, et al. Det ec t ion of ret roperit oneal met ast ases in early - st age nonseminomat ous t est ic ular c anc er: analy sis of dif f erent CT c rit eria. AJR Am J Roent genol 1987;149:1187–1190. 307. St omper PC, Kalish LA, Garnic k MB, et al. CT and pat hologic predic t iv e f eat ures of residual mass hist ologic f indings af t er c hemot herapy f or nonseminomat ous germ c ell t umors: c an residual malignanc y or t erat oma be exc luded? Radiology 1991;180: 711–714.

308. Suey oshi E, Sakamot o I, Mat suoka Y , et al. Aort oiliac and low er ext remit y art eries: c omparison of t hree- dimensional dy namic c ont rast - enhanc ed subt rac t ion MR angiography and c onv ent ional angiography . Radiology 1999;210:683–688. 309. Sulliv an VV, Voris T K, Borlaza GS, et al. Inc ident al disc ov ery of an inf erior v ena c av a aneury sm. Ann Vasc Sur g 2002;16:513–515. 310. Sw ensen SJ, Mc Leod RA, St ephens DH. CT of ext rac ranial hemorrhage and hemat omas. AJR Am J Roent genol 1984;143:907–912. 311. Sw ensen SJ, Keller PL, Berquist T H, et al. Magnet ic resonanc e imaging of hemorrhage. AJR Am J Roent genol 1985;145:921–927. 312. T akashima T , Onoda N, Ishikaw a T , et al. T umor- f orming idiopat hic ret roperit oneal f ibrosis: report of a c ase. Sur g T oday 2004;34: 374–378. 313. T eit elbaum GP, Bradley WGJ, Klein BD. MR imaging art if ac t s, f erromagnet ism and magnet ic t orque of int rav asc ular f ilt ers, st ent s, and c oils. Radiology 1988;16:657–664. 314. T eit elbaum GP, Ort ega HV, Vinit ski S, et al. Low - art if ac t int rav asc ular dev ic es: MR imaging ev aluat ion. Radiology 1988;168: 713–719. 315. T ennant WG, Hart nell GG, Baird RN, et al. Inf lammat ory aort ic aneury sms: c harac t erist ic appearanc es on magnet ic resonanc e imaging. Eur J Vasc Sur g 1992;6:399–402. 316. T ennant WG, Hart nell GG, Baird RN, et al. Radiologic inv est igat ion of abdominal aort ic aneury sm disease: c omparison of t hree modalit ies in st aging and t he det ec t ion of inf lammat ory c hange. J Vasc Sur g 1993;17:703–709. 317. T hornt on F J, Kandiah SS, Monkhouse WS, et al. Helic al CT ev aluat ion of t he perirenal spac e and it s boundaries: a c adav eric st udy . Radiology 2001;218:659–663. 318. T hurnher S, Cejna M. Imaging of aort ic st ent - graf t s and endoleaks. Radiol Clin Nor t h Am 2002;40:799–833.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2652

17 - Retroperitoneum 319. T hurnher SA, Dorf f ner R, T hurnher MM, et al. Ev aluat ion of abdominal aort ic aneury sm f or st ent - graf t plac ement : c omparison of gadoliniumenhanc ed MR angiography v ersus helic al CT angiography and digit al subt rac t ion angiography . Radiology 1997;205:341–352. 320. T odd CS, Mic hael H, Sut t on G. Ret roperit oneal leiomy osaroma: eight c ases and a lit erat ure rev iew . Gy nec ol Onc ol 1995;59:333–337. 321. T orabi M, Aquino SL, Harisinghani MG. Current c onc ept s in ly mph node imaging. J Nuc l Med 2004;45:1509–1518. 322. T orres WE, Maurer DE, St einberg HV, et al. CT of aort ic aneury sms: t he dist inc t ion bet w een mural and t hrombus c alc if ic at ion. AJR Am J Roent genol 1988;150:1317–1319. 323. T orsello GB, Klenk E, Kasprzak B. Rupt ure of abdominal aort ic aneury sm prev iously t reat ed by endov asc ular st ent graf t . J Vasc Sur g 1998;28:184–187. 324. T riant opoulou C, Rizos S, Bourli A, et al. Loc alized unilat eral perirenal f ibrosis: CT and MRI appearanc es. Eur Radiol 2002; 12:2743–2746. 325. T seng CA, Pan Y S, Su Y C, et al. Ext rarenal ret roperit oneal angiomy olipoma: c ase report and rev iew of t he lit erat ure. Abdom Im aging 2004;29:721–723. 326. Unger EC, Glazer HS, Lee JKT , et al. MRI of ext rac ranial hemat omas: preliminary observ at ions. AJR Am J Roent genol 1986; 146:403–407. P.1232 327. Unt erw eger M, Wiesner W, Pret re R, et al. Spiral CT in an ac ut e spont aneous aort o- c av al f ist ula. Eur Radiol 2000;10:733–735.

328. Vac c ari G, Cac iolli S, Calamai G, et al. Int ramural hemat oma of t he aort a: diagnosis and t reat ment . Eur J Car diot hor ac Sur g 2001; 19:170–173. 329. Vallabhaneni SR, Mc Williams RG, Anbarasu A, et al. Perianeury smal f ibrosis: a relat iv e c ont ra- indic at ion t o endov asc ular repair. Eur J Vasc Endov asc Sur g 2001;22:535–541. 330. Van Boc kel SR, Mindelzun RE. Gas in t he psoas musc le sec ondary t o an int rav ert ebral v ac uum c lef t : CT c harac t erist ic s. J Com put Assist T om ogr 1987;11:913–915. 331. v an den Akker PJ, Brand R, v an Sc hilf gaarde R, et al. F alse aneury sms f rom prost het ic rec onst ruc t ions f or aort oiliac obst ruc t iv e disease. Ann Sur g 1989;210:658–666.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2653

17 - Retroperitoneum 332. Van Hoe L, Baert AL, Gry speerdt S, et al. Supra- and juxt arenal aneury sms of aort a: preoperat iv e assessment w it h t hin- sec t ion spiral CT . Radiology 1996;198:443–448. 333. v an Olf f en T B, Knippenberg LH, v an der Vliet JA, et al. Primary aort oent eric f ist ula: report of six new c ases. Car diov asc Sur g 2002;10:551–554. 334. v an Rooij WJJ, Mart ens F , Verbeet en BJ, et al. CT and MR imaging of leiomy osarc oma of t he inf erior v ena c av a. J Com put Assist T om ogr 1988;12:415–419. 335. v anSonnenberg E, Wit t ic h GR, Casola G, et al. Ly mphoc eles: imaging c harac t erist ic s and perc ut aneous management . Radiology 1986;161:593–596.

336. Vernhet H, Serf at y JM, Serhal M, et al. Abdominal CT angiography bef ore surgery as a predic t or of post operat iv e deat h in ac ut e aort ic dissec t ion. AJR Am J Roent genol 2004;182:875–879. 337. Vinnic ombe SJ, Norman AR, Nic holson V, et al. Normal pelv ic ly mph nodes: ev aluat ion w it h CT af t er bipedal ly mphangiography . Radiology 1995;194:349–355. 338. Vinnic ombe SJ, Reznek RH. Comput erised t omography in t he st aging of Hodgkin's disease and non- Hodgkin's ly mphoma. Eur J Nuc l Med Mol Im aging 2003;30[suppl 1]:S42–S55. 339. Viv as I, Nic olas AI, Velazquez P, et al. Ret roperit oneal f ibrosis: t y pic al and at y pic al manif est at ions. Br J Radiol 2000;73:214–222. 340. Vosshenric h R, F isc her U. Cont rast - enhanc ed MR angiography of abdominal v essels: is t here st ill a role f or angiography ? Eur Radiol 2002;12:218–230. 341. Waligore MP, St ephens DH, Soule EH, et al. Lipomat ous t umors of t he abdominal c av it y : CT appearanc e and pat hologic c ondit ions. AJR Am J Roent genol 1981;137:539–545. 342. Wallis F , Rodit i GH, Redpat h T W, et al. Inf lammat ory abdominal aort ic aneury sms: diagnosis w it h gadolinium enhanc ed T 1- w eight ed imaging. Clin Radiol 2000;55:136–139. 343. Warakaulle DR, Premat illeke I, Moore NR. Ret roperit oneal f ibrosis mimic king ret roc rural ly mphadenopat hy . Clin Radiol 2004;59:292–293. 344. Warnke RA, Weiss LM, Chan JKC, et al. T um or s of t he ly m ph nodes and spleen, Series 3 ed. Washingt on, DC: Armed F orc es Inst it ut e of Pat hology , 1994:53–62.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2654

17 - Retroperitoneum 345. Weiner JI, Chako AC, Mert en CW, et al. Breast and axillary t issue MR imaging: c orrelat ion of signal int ensit ies and relaxat ion t imes w it h pat hologic f indings. Radiology 1986;160:299–305. 346. Weinreb JC, Cohen JM, Marav illa KR. Iliopsoas musc les: MR st udy of normal anat omy and disease. Radiology 1985;156:435–440. 347. Welc h T J, St anson AW, Sheedy II PF , et al. Radiologic ev aluat ion of penet rat ing aort ic at herosc lerot ic ulc er. Radiogr aphic s 1990;10: 675–685. 348. Whit aker SC. Imaging of abdominal aort ic aneury sm bef ore and af t er endoluminal st ent - graf t repair. Eur J Radiol 2001;39:3–15.

349. Whit e GH, May J, Waugh RC, et al. T y pe III and t y pe IV endoleak: t ow ard a c omplet e def init ion of blood f low in t he sac af t er endoluminal AAA repair. J Endov asc Sur g 1998;5:305–309. 350. Whit e GH, May J, Pet rasek P, et al. Endot ension: an explanat ion f or c ont inued AAA grow t h af t er suc c essf ul endoluminal repair. J Endov asc Sur g 1999;6:308–315. 351. William MP, Cook JV, Duc hesne GM. Psoas nodes—an ov erlooked sit e of met ast asis f rom t est ic ular t umours. Clin Radiol 1989;40:607–609. 352. Williams DM, Joshi A, Drake MD, et al. Aort ic c obw ebs: an anat omic marker ident if y ing t he f alse lumen in aort ic dissec t ion—imaging and pat hologic c orrelat ion. Radiology 1994;190: 167–174. 353. Williams DM, Lee DY , Hamilt on BH, et al. T he dissec t ed aort a: part III. Anat omy and radiologic diagnosis of branc h- v essel c ompromise. Radiology 1997;203:37–44. 354. Williams MP, Ollif f JF C. Case report : c omput ed t omography and magnet ic resonanc e imaging of dilat ed lumbar ly mphat ic t runks. Clin Radiol 1989;40:321–322. 355. Willmann JK, Wildermut h S, Pf ammat t er T , et al. Aort oiliac and renal art eries: prospec t iv e int raindiv idual c omparison of c ont rast - enhanc ed t hreedimensional MR angiography and mult i- det ec t or row CT angiography . Radiology 2003;226:798–811. 356. Willot eaux S, Lions C, Gaxot t e V, et al. Imaging of aort ic dissec t ion by helic al c omput ed t omography . Eur Radiol 2004;14:1999–2008. 357. Wilmink AB, F orshaw M, Quic k CR, et al. Ac c urac y of serial sc reening f or abdominal aort ic aneury sms by ult rasound. J Med Sc r een 2002;9:125–127. 358. Wolf f KA, Herold CJ, T empany CM, et al. Aort ic dissec t ion: at y pic al pat t erns seen at MR imaging. Radiology 1991;181:489–495.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2655

17 - Retroperitoneum 359. Wolv erson MK, Crepps LF , Sundaram M, et al. Hy perdensit y of rec ent hemorrhage at body c omput ed t omography : inc idenc e and morphologic v ariat ion. Radiology 1983;148:779–784. 360. Woodring JH, How ard RS 2nd, Johnson MV. Massiv e low - at t enuat ion mediast inal, ret roperit oneal, and pelv ic ly mphadenopat hy on CT f rom ly mphangioleiomy omat osis. Case report . Clin Im aging 1994;18:7–11. 361. Wy soki MG, Angeid- Bac kman E, Izes BA. Iliopsoas my osit is mimic king appendic it is: MRI diagnosis. Skelet al Radiol 1997;26: 316–318. 362. Y amada AH, Sherrod AE, Bosw ell W, et al. Massiv e ret roperit oneal hemorrhage f rom adrenal gland met ast asis. Ur ology 1992; 40:59–62. 363. Y amada T , T ada S, Harada J. Aort ic dissec t ion w it hout int imal rupt ure: diagnosis w it h MR imaging and CT . Radiology 1988;168: 347–352. 364. Y ang DM, Jung DH, Kim H, et al. Ret roperit oneal c y st ic masses: CT , c linic al and pat hologic f indings and lit erat ure rev iew . Radiogr aphic s 2004;24:1353–1365.

365. Y ang WT , Lam WWM, Y u MY , et al. Comparison of dy namic helic al CT and dy namic MR imaging in t he ev aluat ion of pelv ic ly mph nodes in c erv ic al c anc er. AJR Am J Roent genol 2000;175: 759–766. 366. Y asuhara H, Mut o T . Inf ec t ed abdominal aort ic aneury sm present ing w it h sudden appearanc e: diagnost ic import anc e of serial c omput ed t omography . Ann Vasc Sur g 2001;15:582–585. 367. Y ekeler E, Genc hellac H, Emiroglu H, et al. MDCT Appearanc e of idiopat hic sac c ular aneury sm of t he inf erior v ena c av a. AJR Am J Roent genol 2004;183:863–864. 368. Y uc el EK, Silv er MS, Cart er AP. MR angiography of normal pelv ic art eries: c omparison of signal int ensit y and c ont rast - t o- noise rat io f or t hree dif f erent inf low t ec hniques. AJR Am J Roent genol 1994;163:197–201. 369. Zeman RK, Cronan JJ, Rosenf ield AT , et al. Renal c ell c arc inoma: dy namic t hin- sec t ion CT assessment of v asc ular inv asion and t umor v asc ularit y . Radiology 1988;167:393–396. 370. Zeppa MA, F orrest JV. Aort oent eric f ist ula manif est ed as an int ramural duodenal hemat oma. AJR Am J Roent genol 1991;157: 47–48. 371. Zhang Y , Nishimura H, Kat o S, et al. MRI of ganglioneuroma: hist ologic c orrelat ion st udy . J Com put Assist T om ogr 2001;25: 617–623. 372. Zissin R, Gay er G, Kot s E, et al. Iliopsoas absc ess: a report of 24 pat ient s diagnosed by CT . Abdom Im aging 2001;26:533–539.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

Thi s pa ge i s i ntenti ona l l y l eft bl a nk. Remove thi s text from the ma nua l templ a te i f you wa nt i t compl etel y bl a nk.

18 - The Kidney and Ureter

2658

18 - The Kidney and Ureter 23

18 - The Kidney and Ureter Editors: Le e , Jose ph K. T. ; Sa ge l, Stua rt S. ; Sta nle y , Robe rt J. ; He ike n, Ja y P. Title : C ompute d Body Tomogra phy with MRI C orre la tion , 4th Edition Copy right В©2006 Lippinc ot t Williams & Wilkins > T able of Cont ent s > 18 - T he Kidney and Uret er

18 The Kidney and Ureter Ma rk E. Loc kha rt Ke v in J. Smith Philip J. Ke nne y Renal imaging c an be perf ormed using any of a w ide selec t ion of radiologic modalit ies, inc luding c omput ed t omography (CT ), magnet ic resonanc e imaging (MRI), ult rasound, nuc lear medic ine, int rav enous urography , or ev en c onv ent ional radiography . CT is espec ially usef ul in genit ourinary imaging, bec ause more prot oc ols hav e been c reat ed t o ev aluat e renal lesions, renal v asc ulat ure, and t he urot helial st ruc t ures. T he last 5 t o 10 y ears hav e seen dramat ic c hanges in t he abilit y of CT sc anners t o image f ast er w it h great er resolut ion. Using t his new t ec hnology , CT has aided in t he ev aluat ion of urinary lit hiasis, renal masses, and adrenal lesions. CT or MRI urography has pot ent ial t o replac e int rav enous urography in t he ev aluat ion f or t ransit ional c ell c arc inoma. While t he benef it of ot her imaging modalit ies c annot be f orgot t en, CT has bec ome t he w orkhorse of renal imaging in many inst it ut ions.

NORMAL ANATOMY Anatomy In t he t y pic al pat ient , t here are t w o kidney s, eac h of w hic h c onsist s of a peripheral c ort ex, c ent ral medulla, renal sinus f at , v essels, and urot helial st ruc t ures. T he kidney s are loc at ed w it hin t he ret roperit oneal spac e t o eac h side of t he v ert ebral bodies at t he lev el of T 10- L2 (F ig. 18- 1). T he lef t kidney is of t en loc at ed slight ly more c ranial t han t he right kidney . T he kidney s are generally sy mmet ric in size and appearanc e, but t he lef t kidney may also be slight ly longer t han t he right kidney . T he kidney s are usually larger in male

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2659

18 - The Kidney and Ureter

pat ient s and should reac h f ull size by t he lat e t eens. T he normal range of t he kidney size is v ariable based on pat ient height w it h median lengt h 11 c m, and most are w it hin a range of 9.8 t o 12.3 c m. T he c ort ic al t hic kness of t he kidney s is usually sy mmet ric . T he mean t hic kness of t he c ort ex is approximat ely 10 mm, based on sonographic st udies (130). T he kidney margins are generally smoot h, but t here may be small indent at ions of t he normal renal margin (F ig. 18- 2). A t hin c apsule surrounds t he kidney , but t he c apsule is not t y pic ally v isualized by imaging in normal pat ient s. It should be not ed t hat in pat ient s w it h renal art ery oc c lusion t he c apsular region c ould be v isible, as c apsular art eries c reat ing a t hin rim of enhanc ement at t he periphery of t he kidney may supply it (187). Bey ond t he renal c apsule is t he perinephric spac e, w hic h c ont ains f at and t hin f ibrous sept at ions. T he perinephric f at is c ont ained w it hin Gerot a's f asc ia. Gerot a's f asc ia also surrounds t he adrenal, w hic h is separat ed f rom t he kidney by a t ransv erse sept um. T he ant erior and post erior renal f asc ias separat e t he kidney and adrenal f rom ot her adjac ent spac es. If t he f asc ia bec omes t hic kened due t o f luid or ot her c auses, it may be v isible (413). Eac h kidney is supplied by one or more renal art eries, w hic h originat e f rom t he aort a below t he lev el of t he superior mesent eric art ery or rarely f rom t he iliac art eries. Single bilat eral renal art eries are t he most c ommon c onf igurat ion and t he renal art eries c ourse ant erior and medial t o t he kidney (see F ig. 18- 2). How ev er, in approximat ely 24% t o 30% of kidney s, t here w ill be mult iple renal art eries (90,253). T he right main renal art ery t y pic ally passes post erior t o t he IVC, but prec av al art eries are present in 5% of pat ient s (562). T he main renal art ery t y pic ally div ides at t he renal hilum t o f orm a dorsal and v ent ral branc h. T he dorsal and v ent ral branc hes subsequent ly div ide int o segment al renal art eries. In approximat ely one f if t h of renal art eries, t here may be early branc hing of t he renal art eries w it hin 2 c m of t he origin of t he main renal art eries (253). T he renal art eries may also be in c lose assoc iat ion w it h t he c ollec t ing sy st em or proximal uret er. T his may bec ome P.1234 import ant w hen t here is obst ruc t ion bec ause a c rossing v essel may be assoc iat ed w it h a uret eropelv ic junc t ion obst ruc t ion and may result in periuret eral hemorrhage if t he st enosis is t reat ed endosc opic ally (444,487). T he presenc e of a c rossing v essel also signif ic ant ly dec reases t he suc c ess rat e of endopy elot omy f or UPJ obst ruc t ion (345).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2660

18 - The Kidney and Ureter

F igure 18- 1 Normal CT urography . Abdominal CT w it h t hin slic es and exc ret ory phase imaging demonst rat es normal opac if ic at ion of t he c ollec t ing sy st ems and uret ers t o t he urinary bladder. Coronal v olume rendered images present inf ormat ion in a f ormat similar t o int rav enous urography .

T he renal v enous drainage is ext remely v ariable in number and loc at ion of t he v eins. T he renal v ein of t he right kidney drains direc t ly int o t he IVC. T he renal v ein of t he lef t kidney is t y pic ally longer and c ourses ant erior t o t he aort a unt il it reac hes t he IVC. Anomalous renal v eins oc c ur in approximat ely 11% of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2661

18 - The Kidney and Ureter

lef t kidney s (253). In t he most c ommon v ariant , t w o t ribut aries of a lef t renal v ein may enc irc le t he aort a (a c irc umaort ic lef t renal v ein) (F ig. 18- 3). In t he sec ond most c ommon v ariant , t he lef t renal v ein may c ourse behind t he aort a t o t he IVC (a ret roaort ic lef t renal v ein) (see F ig. 18- 2). T he post erior c omponent of a c irc umaort ic or ret roaort ic renal v ein is of t en loc at ed c audal t o t he lev el of t he kidney s in it s c ourse t o t he IVC. T he normal lef t adrenal v ein and lef t gonadal v ein drain int o t he lef t renal v ein (F ig. 18- 4).

F igure 18- 2 Normal renal CT angiogram. Volume rendered image f rom a CT angiogram on a pot ent ial renal donor. T here are single renal art eries bilat erally w it h a slight ly prehilar branc h on t he right . Not e t he somew hat lobular c ont our of t he kidney s, t he slight lat eral t ilt of t he low er poles and t he slight ant erior rot at ion of t he renal hila. T here is also a ret ro- aort ic lef t renal v ein (ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2662

18 - The Kidney and Ureter GENERAL PRINCIPLES OF RENAL IMAGING Computed Tomography: Normal Appearance and Technique Normal Computed Tomography Mult iplanar imaging of t he kidney s c an prov ide exquisit e anat omic det ail. T he

normal smoot h c ont ours, c ranioc audal orient at ions, and int ernal st ruc t ures c an be demonst rat ed easily and mimic gross pat hologic al spec imens. T he densit ies of t he renal medulla and renal c ort ex on non- enhanc ed CT are v ery similar, and t hey are similar t o t he at t enuat ion of t he liv er. T he renal parenc hy ma t y pic ally ranges f rom 27 t o 47 Hounsf ield unit s on non- enhanc ed CT (499). T he renal sinus is most c ommonly ant erior and medial t o t he parenc hy mal t issue, and it is easily dif f erent iat ed f rom t he parenc hy ma by it s f at at t enuat ion, ev en w it hout int rav enous c ont rast . T he c ent ral renal sinus has f at at t enuat ion w it h linear f luid- at t enuat ion renal v essels c oursing f rom t he aort a and t ow ard t he inf erior v ena c av a. T he urot helial t rac t also originat es in t he renal sinus f at at t he ant eromedial aspec t of t he kidney , and in t his region it inc ludes t he renal c aly c es and renal pelv is. T he c ollec t ing sy st em is usually c ollapsed, but t here may be a small amount of c aly c eal f luid present . T he appearanc e of t he kidney s v aries w it h t he t iming of delay unt il image ac quisit ion af t er t he injec t ion of int rav enous iodinat ed c ont rast . On nonenhanc ed CT , t he P.1235 c ent ral medullary port ion of t he parenc hy ma is not dif f erent iat ed f rom t he c ort ex in normal kidney s. Wit hin 15 t o 25 sec onds of injec t ion of int rav enous c ont rast , t he aort a and renal art eries opac if y w it h c ont rast , as may be seen in CT angiography . During art erial phase of c ont rast enhanc ement , t he c ort ex and medulla enhanc e at dif f erent rat es w it h bright c ort ex juxt aposed t o t he less enhanc ed medulla (F ig. 18- 5A). Wit h st andard injec t ion rat es, t he c ort ex enhanc es t o 70 HU during art erial phase and doubles t o 145 HU w it hin 40 sec onds af t er injec t ion. T he medulla only enhanc es t o less t han 60 HU by 50 sec onds (499). At approximat ely 100 t o 120 sec onds af t er c ont rast injec t ion, during t he nephrographic phase (F ig. 18- 5B), t he enhanc ement of t he c ort ex

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2663

18 - The Kidney and Ureter and medulla equilibrat es measuring at least 120 HU (499). T he renal parenc hy ma of a normal kidney is homogeneous in t he nephrographic phase w it h sharp delineat ion of t he non- enhanc ing c ent ral renal sinus f at . Af t er at least 3 minut es af t er injec t ion, exc ret ion f rom t he renal t ubules begins t o f ill

t he renal c aly c es and renal pelv is, know n as t he exc ret ory phase (F ig. 18- 5C). At t his t ime, t he renal medulla may be slight ly more enhanc ed t han t he c ort ex as c ont rast is exc ret ed f rom t he renal t ubules. During t he exc ret ory phase, dense c ont rast f ills t he c ollec t ing sy st ems, t he uret ers, and ev ent ually t he urinary bladder.

F igure 18- 3 Circ umaort ic lef t renal v ein. Coronal- obliqued maximum int ensit y projec t ion (MIP) image A: axial- obliqued image B: f rom a CT angiogram on a pot ent ial renal donor show s t he normally loc at ed ant erior lef t renal v ein and a smaller post erior branc h (ar r ow s). Not e t hat t he MIP rec onst ruc t ion may art if ac t ually appear as if t he aort a is ant erior t o t he v ein.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2664

18 - The Kidney and Ureter

F igure 18- 4 Normal lef t renal v ein. Slab MIP image f rom a CT angogram on a pot ent ial renal donor show t he lef t gonadal v ein (arrow s) and lef t adrenal v ein (arrow heads) joining t he lef t renal v ein t o t he lef t of t he aort a. Loc alizing t hese t ribut aries is c rit ic al during laparosc opic nephrec t omy .

Computed Tomography Technique T he CT t ec hnique t hat is c hosen v aries w it h t he indic at ion f or t he st udy . A dec ision must be made w het her t o use int rav enous c ont rast . T here are numerous indic at ions, suc h as ret roperit oneal hemat oma or nephrolit hiasis, t hat do not nec essarily require int rav enous c ont rast . Ev en in t hese sit uat ions, spec if ic quest ions may arise w hic h nec essit at e int rav enous iodinat ed c ont rast administ rat ion. Of t en, t he dist al P.1236 uret ers are dif f ic ult t o v isualize in t he c linic al quest ion of nephrolit hiasis, and int rav enous c ont rast may enable t he uret ers t o be separat ely v isualized f rom any c alc if ied pelv ic phlebolit hs. Int rav enous c ont rast should be judic iously administ ered sinc e t here is alw ay s a risk of anaphy lac t ic reac t ion or ev en deat h. In pat ient s w it h renal dy sf unc t ion, t here is also t he risk of c ont rast induc ed nephrot oxic it y , w hic h may result in t emporary renal insuf f ic ienc y ,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2665

18 - The Kidney and Ureter permanent renal f ailure, or ev en deat h (330,512). T he c linic al benef it of int rav enous c ont rast usually f av ors it s administ rat ion despit e t he possible c omplic at ions. Cont rast enhanc ement signif ic ant ly improv es t he v isualizat ion of t he abdominal and pelv ic st ruc t ures and enables v asc ular c harac t erizat ion. Af t er a delay , t he urot helial sy st em may be ev aluat ed w it h t hin slic e CT , know n as CT urography . T he selec t ion of int rav enous c ont rast also has sev eral c onsiderat ions. F or many y ears, high- osmolar c ont rast w as t he st andard of c are. Researc h demonst rat ed reduc ed nephrot oxic it y of low - osmolar c ont rast c ompared w it h high- osmolar agent s (171). Bec ause of a large dif f erenc e in t he c ost of low osmolar ov er high- osmolar c ont rast , univ ersal administ rat ion of low - osmolar c ont rast w as not immediat ely c hosen. As t he c ost of low - osmolar c ont rast dec reased and t he dif f erenc e in c ost bec ame less sev ere, univ ersal administ rat ion of low - osmolar CT c ont rast bec ame t he st andard in many hospit als. A similar sit uat ion is c urrent ly in c onsiderat ion as new dimeric isosmolar nonionic c ont rast agent s hav e been show n t o hav e less

nephrot oxic it y t han st andard low - osmolar agent s (13). T hese c ont rast agent s hav e a signif ic ant ly higher c ost t han t he st andard low - osmolar agent s, and based on inst it ut ional guidelines, t hey may be giv en in selec t ed sit uat ions rat her t han as a univ ersal polic y .

F igure 18- 5 Dif f erent phases of normal renal c ont rast enhanc ement . Coronal t hin slab ref ormat t ed images f rom a CT w it h c ont rast show t he c ort ic o-

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2666

18 - The Kidney and Ureter medullary phase (A), w hen t he c ort ex has enhanc ed but t he medulla is nearly unenhanc ed, t he nephrographic phase (B), w hen t he c ort ex and medulla are

more similarly enhanc ed, and t he urographic or exc ret ory phase (C ), w hen t he c ort ex has st art ed t o w ash out and t he py ramids and c ollec t ing sy st ems are int ensely opac if ied. It is helpf ul t o ov erhy drat e pat ient s or administ er diuret ic t o dilut e t he urinary c ont rast t o prev ent CT art if ac t s. Not e also single parapelv ic c y st on t he right (ar r ow s).

Pat ient s w it h mildly or moderat ely elev at ed c reat inine are generally hy drat ed prior t o int rav enous c ont rast administ rat ion. A bic arbonat e solut ion may be used t o reduc e t he amount of c ont rast - induc ed nephrot oxic it y w hen t he c reat inine is elev at ed (338). In t hese pat ient s, w e t y pic ally use t he new er iso- osmolar c ont rast agent s in an addit ional at t empt t o prev ent nephrot oxic it y . Usef ulness of oral N- ac et y lc y st eine has not been demonst rat ed in a rec ent large randomized t rial (543). In c ases of ac ut e renal f ailure, sev ere renal f ailure not on dialy sis, or sev ere prior allergic reac t ion, it may be t hought t hat no iodinat ed c ont rast c an be saf ely giv en. A premedic at ion prot oc ol f or allergic reac t ions may be used, but pat ient s may st ill hav e lif e- t hreat ening allergic reac t ions in t he f ac e of st andard premedic at ion if t he prior reac t ion w as sev ere (313). In t hese c ases, a c ombinat ion of nonc ont rast CT and MRI or ult rasound may answ er many c linic al quest ions. MRI st ill has a v ery usef ul role in pat ient s w it h renal insuf f ic ienc y bec ause int rav enous gadolinium at rout ine dosage does not af f ec t renal f unc t ion. Int rav enous gadolinium also does not hav e t he similar high number of anaphy lac t ic reac t ions as iodinat ed CT c ont rast , and c ont rast MRI is of t en c hosen in pat ient s w it h an allergic hist ory (265). In addit ion t o t he c onsiderat ion of int rav enous c ont rast , t he administ rat ion of oral c ont rast may also pose a P.1237 c linic al dilemma. T he st andard of c are f or abdominal CT inc ludes oral administ rat ion of 2 t o 3 c ups of dilut ed iodinat ed c ont rast . If possible, oral c ont rast is giv en t ime t o pass int o t he small bow el t o allow bet t er c harac t erizat ion of t he bow el and t o improv e det ec t ion of any f ree abdominal f luid. How ev er, t here are c ert ain sit uat ions in w hic h oral c ont rast may not be pref erred. In t he ev aluat ion of nephrolit hiasis, oral c ont rast may hinder t he det ec t ion of uret eral c alc uli if dense c ont rast in bow el is adjac ent t o t he uret er. In CT angiography , dense oral c ont rast w ill limit mult iplanar and 3D rec onst ruc t ions of t he v asc ular sy st em. Wat er may be used as a negat iv e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2667

18 - The Kidney and Ureter

c ont rast agent t o allow bet t er c harac t erizat ion of t he bow el in t hese pat ient s. In an obt unded t rauma pat ient w it h maxillof ac ial or c ranial t rauma, t he t rauma surgeons may pref er t o rapidly perf orm t he emergent t rauma CT w it hout oral c ont rast . CT of renal disease of t en requires mult iple series of images at dif f erent t imings relat iv e t o int rav enous c ont rast administ rat ion. T hin slic es, 1 t o 2 mm, are of t en perf ormed on new er mult idet ec t or- row mac hines. T he new est CT sc anners hav e built - in dose reduc t ion algorit hms, but mult iple series w it h t hin slic es w ill st ill administ er a large dose of radiat ion t o t he pat ient . Eac h f ull sequenc e of images should be c aref ully c onsidered as t o w het her it w ould prov ide signif ic ant addit ional inf ormat ion. At our inst it ut ion, w e w ill t y pic ally rev iew nonc ont rast st one CT images t o det ermine if t he c linic al quest ion is answ ered bef ore w e dec ide w het her repeat ed images w it h int rav enous c ont rast should be perf ormed. T his is espec ially import ant w it h y oung pat ient s w ho hav e nephrolit hiasis and may of t en require numerous CT st udies during t heir y oung adult y ears. Reduc t ion of radiat ion dosage in t hese pat ient s is import ant t o limit pot ent ial c arc inogenic ef f ec t s at a lat er age. In pat ient s w it h a know n malignanc y , t he dosage issue is less of a c linic al c onc ern sinc e t he c rit ic al import anc e is ac c urat e diagnosis and st aging of t umor or t umor rec urrenc e. In many of t hese c ases, t he expec t ed lif e span of t he pat ient w ill be signif ic ant ly reduc ed if inadequat e images do not det ec t rec urrent disease. Our mult iphase renal mass prot oc ol inc ludes prec ont rast 3- t o 5- mm images of t he kidney s f ollow ed by 3- t o 5- mm images of t he abdomen and pelv is af t er int rav enous c ont rast . If t here is quest ion of urot helial abnormalit y , 1- mm exc ret ory phase images are obt ained t hrough t he kidney s t o t he pelv is t o allow CT urography rec onst ruc t ion images. Images are perf ormed af t er a 4- t o 10- minut e delay af t er int rav enous c ont rast administ rat ion. At our inst it ut ion, 4 c ups of w at er are giv en prior t o CT t o help dist end t he uret ers. Alt ernat iv ely , a 250- mL normal saline inf usion c an be giv en immediat ely af t er t he c ont rast injec t ion t o improv e t he dist ent ion of t he renal pelv is and uret ers f or t his ev aluat ion (65,335). Some inst it ut ions also f av or f urosamide administ rat ion t o improv e uret eral dist ent ion. T hin slic es, maximum int ensit y projec t ion, and v olumet ric t ec hniques of t he CT dat a in a c oronal plane (F ig. 18- 6) are used t o simulat e t he appearanc e of c onv ent ional int rav enous urography .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2668

18 - The Kidney and Ureter

F igure 18- 6 CT urogram. Coronal t hic k slab MIP projec t ion f rom a CT urogram on a pat ient w it h hemat uria simulat es IVU, but w it h remov al of ov erlapping st ruc t ures suc h as t he bow el and t he sac rum. Adequat e hy drat ion or diuret ic administ rat ion is import ant t o ac hiev e uret eral dist ension. An enlarged prost at e c auses elev at ion of t he bladder f loor.

MRI: NORMAL APPEARANCE AND TECHNIQUE

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2669

18 - The Kidney and Ureter Normal Magnetic Resonance Imaging On nonenhanc ed T 1- w eight ed sequenc es, t he signal int ensit y of t he normal

kidney on MRI is similar t o t he appearanc e of ot her abdominal organs, suc h as t he liv er. T he renal c ort ic al t issue has moderat e T 1 signal c harac t erist ic s. In t he absenc e of f at suppression, t he renal sinus has t y pic al f at int ensit y , c onsist ing of high T 1 (F ig. 18- 7) and moderat e T 2 signals. How ev er, T 1 w eight ed images generally employ f at suppression. F at sat urat ion reduc es t he high signal f rom surrounding f at t o allow improv ed v isualizat ion of t he kidney (449). Moderat ely high T - 2 signal c harac t erist ic s are present in t he renal medulla and c ort ex. Af t er gadolinium passes t hrough t he renal art eries t o t he kidney s, t he c ort ex and medulla c an be sharply dif f erent iat ed if t here is an imaging delay of less t han 70 sec onds af t er injec t ion. T he nephrographic phase, approximat ely 100 sec onds af t er injec t ion, w ill c reat e a homogeneous P.1238 enhanc ement of t he renal parenc hy ma, similar t o CT . T he perinephric f at w ill be similar t o ot her areas of f at on all sequenc es. In lat er imaging during exc ret ory phase, at least 3 t o 5 minut es af t er c ont rast injec t ion, t he c ont rast in t he renal c ollec t ing sy st em is c onc ent rat ed, and t he c onc ent rat ed c ont rast c reat es a signal v oid due t o magnet ic susc ept ibilit y (85,450).

F igure 18- 7 Normal T 1- w eight ed MRI appearanc e of t he kidney . T he renal parenc hy ma is similar t o ot her sof t t issues and t here is T 1 bright f at in t he renal hilum (arrow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2670

18 - The Kidney and Ureter MRI Technique MRI has bec ome a v aluable t ool in t he ev aluat ion of urinary t rac t disorders.

Numerous t ec hniques hav e been dev eloped t o prov ide rapid imaging w it h good spat ial and c ont rast resolut ion. Respirat ory gat ing t ec hniques help t o reduc e mot ion art if ac t . T 2- w eight ed imaging t y pic ally uses a f ast spin- ec ho t ec hnique and may t ake approximat ely 3 t o 5 minut es per series on st andard mac hines. Axial, c oronal, or sagit t al sourc e imaging is possible. F or imaging of t he ent ire urinary t rac t , c oronal orient at ion may be usef ul, bec ause axial imaging may be unable t o inc lude t he ent ire sy st em adequat ely in one series. Ult raf ast half F ourier t ransf orm t ec hniques also allow T 2- w eight ed imaging, but t he spat ial resolut ion is somew hat less t han seen on F SE t ec hniques; t his limit at ion is part ially of f set by less mot ion or c hemic al shif t art if ac t s (561). St andard spinec ho t ec hniques are t y pic ally no longer perf ormed, and hav e been replac ed w it h gradient rec alled ec ho images suc h as f ast mult iplanar spoiled gradient T 1- w eight ed imaging. New er t hree- dimensional v olumet ric T 1 ac quisit ion sequenc es also prov ide high resolut ion T 1- w eight ed imaging of t he kidney s. MR angiography has ev olv ed f rom prev ious nonc ont rast t ime- of - f light images based on f low of unenhanc ed blood t o gadolinium enhanc ed breat h- hold spoiled gradient ev aluat ions, w hic h hav e ov erc ome prev ious in- plane f low art if ac t s. Int rav enous gadolinium c ont rast (0.1 t o 0.3 mmol/kg) is used t o short en t he T 1 relaxat ion t ime of v asc ularized t issues and inc rease T 1w eight ed signal in enhanc ed st ruc t ures. F or art erial ev aluat ion, MR angiographic images should use aut omat ed bolus- t iming t ec hnique or t est bolus t o selec t t he opt imal t ime f or imaging sinc e a st andardized 25- sec ond delay may oc c asionally y ield subopt imal c ont rast opac if ic at ion. Coronal 3- mm or t hinner images w it h no gap are perf ormed. A phased- array surf ac e c oil c an improv e spat ial resolut ion if it w ill c ov er t he region of int erest . St andard MRI imaging of t he kidney inc ludes T 1- and T 2- w eight ed images. Eit her an axial or a c oronal plane of imaging may be c hosen. If a f oc al lesion is ident if ied, a sec ond plane of imaging may be helpf ul f or f urt her c harac t erizat ion and loc alizat ion. Prec ont rast and post c ont rast T 1- w eight ed images are perf ormed t o ev aluat e t he enhanc ement of t he kidney and t o quant it at e enhanc ement of any f oc al lesions t hat are det ec t ed on t he st udy . F at - suppression t ec hniques may assist in t he det ec t ion of enhanc ement sinc e t here is improv ed signal dif f erenc e bet w een t he renal parenc hy ma and t he surrounding st ruc t ures. T 2- w eight ed images are not as usef ul in renal masses

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2671

18 - The Kidney and Ureter

as T 1- w eight ed images bec ause of t he nonspec if ic c harac t erist ic of most renal lesions on T 2 sequenc es. One benef it of T 2- w eight ed imaging is it s abilit y t o det ec t osseous met ast ases and assist in t he det ec t ion of liv er lesions. Cert ain t ec hniques may be usef ul in t he ev aluat ion of spec if ic urologic quest ions. In t he st aging of a renal c ell c arc inoma, c oronal T 2- w eight ed and post c ont rast T 1- w eight ed images t o t he lev el of t he heart may be helpf ul t o c harac t erize possible v ena c av al t hrombus. Heav ily T 2- w eight ed c oronal images of t he urot helial sy st em, MRI urography , c an prov ide usef ul inf ormat ion regarding uret eral t umors, st ric t ures, or obst ruc t ion based on signal obt ained f rom t he urine w it hout int rav enous c ont rast . F or MRI urography , f urosamide or saline bolus may be helpf ul t o dist end t he uret ers (372).

Limitations of Computed Tomography and Magnetic Resonance Imaging CT and MRI are eac h exc ellent modalit ies f or ev aluat ion of t he kidney s and uret ers. Alt hough bot h t ec hniques hav e t ec hnic al limit at ions, CT t ends t o be less expensiv e and more robust and is used as one of t he f irst imaging st udies alongside ult rasound. CT has exc ellent spat ial and c ont rast resolut ion, w hic h is improv ed by t he use of int rav enous c ont rast . Ult raf ast ac quisit ions are possible w it h mult idet ec t or- row sc anners so t hat mot ion art if ac t is reduc ed. CT is limit ed in pat ient s w ho c annot rec eiv e int rav enous iodinat ed c ont rast due t o ac ut e renal f ailure or hist ory of anaphy lac t ic reac t ion t o iodinat ed c ont rast agent s. In t hese pat ient s, MRI is usef ul bec ause int rav enous gadolinium may st ill be giv en in t he set t ing of renal insuf f ic ienc y , and allergy t o MRI c ont rast is ext remely rare (356). How ev er, P.1239 MRI has more susc ept ibilit y t o mot ion art if ac t s, w hic h are c ommon in v ery sic k pat ient s. Ult raf ast 3D MRI sequenc es are making progress t o reduc e t hese mot ion art if ac t s. Pat ient s may hav e ot her c ont raindic at ions t o MRI t hat w ould not prev ent perf ormanc e of a CT examinat ion (i.e., pac emaker or brain aneury sm c lips). In bot h CT and MRI, det erminat ion of w het her t rue enhanc ement of a renal lesion is present may be dif f ic ult . MRI is more sensit iv e t o v asc ularit y w it hin a lesion, but only relat iv e enhanc ement c an be generally desc ribed. CT allow s absolut e enhanc ement measurement , but t he t hreshold may be c hanging in t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2672

18 - The Kidney and Ureter set t ing of new er mult idet ec t or- row sc anners. T here may be signif ic ant pseudoenhanc ement of a lesion result ing f rom inc reased at t enuat ion of t he

enhanc ing adjac ent parenc hy ma. T his is espec ially problemat ic in small lesions on mult idet ec t or- row CT (202). Radiat ion dosage and populat ion radiat ion exposure by medic al imaging is a c onc ern spec if ic t o CT , but not ult rasound or MRI.

CONGENITAL ABNORMALITIES OF THE KIDNEYS Abnormal Location or Fusion Renal ec t opia, or abnormal loc at ion of t he kidney , oc c urs in approximat ely 1/500 t o 900 persons (169). Renal ec t opia oc c urs w hen t he uret eral bud and met anephric blast ema f ail t o migrat e normally . T he most c ommon renal ec t opia w it hout f usion is a pelv ic kidney (302). Of t en a pelv ic kidney w ill be malrot at ed, and t he renal hilum may be abnormally shaped w it h an ev ert ed appearanc e (F ig. 18- 8).

F igure 18- 8 Pelv ic kidney . Axial image f rom a CT w it h c ont rast show s t he somew hat dist ort ed, malrot at ed right pelv ic kidney (arrow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2673

18 - The Kidney and Ureter

F igure 18- 9 Horseshoe kidney . Axial image f rom a c ont rast ed CT show s f usion of t he low er poles ant erior t o t he aort a.

Horseshoe kidney (F ig. 18- 9) is a c ommon t y pe of renal ec t opia t hat represent s t he most c ommon renal f usion anomaly . It oc c urs in approximat ely 1/400 t o 800 persons (339). A horseshoe kidney oc c urs w hen t he poles of t he kidney s (usually low er poles) are f used w it h an ist hmus. T he normal asc ent of t he kidney is halt ed at t he lev el of t he inf erior mesent eric art ery and t he kidney remains loc at ed in t he midline abdomen ant erior t o t he aort a and spine. T he low er poles, medially loc at ed relat iv e t o t he upper poles, are loc at ed below t he lev el of L3 v ert ebral body , a f inding not c ommon in normal kidney s. On CT , t he t w o kidney s are medially loc at ed and are c onnec t ed by a f oc al ist hmus of t issue. T he kidney s and ist hmus t y pic ally enhanc e af t er int rav enous c ont rast . T he renal v asc ulat ure of a horseshoe kidney is usually abnormal w it h numerous v essels supply ing t he kidney s t hrough a c ent ral hilum (443). A horseshoe kidney is at risk f or sev eral c omplic at ions. Bec ause of t he splay ing of t he v asc ulat ure and t he shape of t he kidney , t here is inc reased risk of st asis in t he c ollec t ing sy st em. T he st asis of urine in t he c ollec t ing sy st em may lead t o urinary c alc uli or inc reased c hanc e of urinary inf ec t ion. Urinary c alc uli oc c ur in 20% t o 60% of c ases (275,395), and most are c alc ium st ones (411). In most pat ient s, met abolic abnormalit ies c ont ribut e t o st one f ormat ion (135). Uret eropelv ic junc t ion (UPJ) obst ruc t ion oc c urs in as many as 15% t o 33% of pat ient s (28,259), and t here is assoc iat ion of c rossing v essels in t hese pat ient s. Vesic ouret eral ref lux is c ommon in c hildren w it h horseshoe

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2674

18 - The Kidney and Ureter kidney (448). T here is inc reased risk of injury during t rauma (255). T he presenc e of a horseshoe kidney may also hav e an assoc iat ion w it h c ry pt orc hidit ism, hy pospadias, poly c y st ic kidney s, bladder ext rophy , and uret eral anomalies (40).

F igure 18- 10 Renal c arc inoma in a horseshoe kidney . Coronally orient ed slap v olume rendered images demonst rat e t he f usion of t he low er renal poles and t he renal art erial and v enous anat omy (A) and t he relat ionship of t he v asc ulat ure t o t he right mid- renal t umor (arrow s) (B).

P.1240 In t he horseshoe kidney , sev eral neoplasms may oc c ur; renal c ell c arc inoma (F ig. 18- 10) is most c ommon (436) but not at signif ic ant ly inc reased risk ov er t he general populat ion (216). T here is an inc reased inc idenc e of t ransit ional c ell c arc inoma (216,355), possibly result ing f rom st asis of urine in t he c ollec t ing sy st em. A rare t umor t hat oc c urs t w ic e as of t en in a horseshoe kidney t han in t he general populat ion is a Wilms t umor (339,367). Wilms t umor c an be assoc iat ed w it h a number of urologic abnormalit ies, inc luding horseshoe kidney , c ry pt orc hidism, hy pospadias, pseudohermaphrodit ism, renal ec t opia, or renal hy poplasia (339). In a horseshoe kidney , t he loc at ion of Wilms t umor is ev enly dist ribut ed among t he right kidney , lef t kidney , and t he small ist hmus region (226,367). It present s w it h abdominal mass, hemat uria, t umoral hemorrhage, or hy pot ension at a median age of 3 y ears (226). Surgic al exc ision may be c omplic at ed by t he abnormal v asc ulat ure supply t hat is c ommon in horseshoe kidney s. An ext remely rare t umor t hat has a v ery high assoc iat ion w it h horseshoe kidney is know n as a renal c arc inoid t umor. Alt hough only a small number of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2675

18 - The Kidney and Ureter c ases hav e been desc ribed, approximat ely 15% w ere disc ov ered in horseshoe kidney s (272). T hese pat ient s present w it h abdominal or f lank pain (25). On ult rasound, t he mass may be hy perec hoic relat iv e t o t he rest of t he kidney ,

unlike many ot her renal lesions (234). On CT , t he mass may be solid or appear as a nonenhanc ing hy perdense renal c y st ic lesion (234). Anot her f orm of renal ec t opia is t ermed c r ossed ec t opia, w hic h oc c urs in 1/1,000 persons (1) and is more c ommon in males (144). T his renal c onf igurat ion oc c urs w hen one kidney c rosses t he midline and is at t ac hed t o t he low er pole of t he normally plac ed kidney . Most c rossed kidney s are assoc iat ed w it h renal parenc hy mal f usion (331). Rarely , t here may be a solit ary kidney w it h a single c rossed uret er, or t here may be t w o kidney s w it h c rossing of t he t w o uret ers (331). In c rossed f used ec t opia, art erial and v enous v asc ulat ure is usually at y pic al and may be c omplex (435). T he malposit ioned kidney is of t en malrot at ed. Crossed f used ec t opia usually oc c urs w it h bot h kidney s on t he right side of t he abdomen (331). T he uret er of t he ec t opic kidney insert s int o t he normal expec t ed posit ion at t he lef t uret eral orif ic e of t he bladder (331). T here is inc reased risk f or c omplic at ions, and t hese may nec essit at e t herapy . Complic at ions may inc lude urinary obst ruc t ion, renal c alc uli, uret hral v alv es, hy pospadias, and c ry pt orc hidism (144). CT A or MRI may prov ide usef ul inf ormat ion f or preoperat iv e assessment of f used kidney s (401,443). When nec essary , renal surgery in t hese c ases is of t en c omplex. Preoperat iv e assessment of t he v asc ular supply c an be show n in great det ail w it h CT angiography , t hereby av oiding t he added risk of c at het er angiography prior t o surgery . CT or MRI may demonst rat e a point of f used parenc hy ma ev en if t here is nonf unc t ional t issue in t his region, unlike int rav enous urography . Rarely , an ec t opic kidney may migrat e c ranially int o t he t horax w it h or w it hout an assoc iat ed diaphragmat ic hernia (465). A t horac ic kidney oc c urs in less t han 1/10,000 persons (126). T he abnormalit y is more c ommon in males and usually oc c urs in t he lef t hemit horax (126). It is usually det ec t ed inc ident ally bec ause most are asy mpt omat ic w it hout t he assoc iat ed c omplic at ions t hat oc c ur in ot her ec t opic kidney s (465). T he kidney may be mist aken as a P.1241 mass on radiography , but t he diagnosis should be easily c larif ied on IVU, CT , or MRI. In one c ase, St anley et al. (316) show ed t hat t he blood supply t o t he int rat horac ic kidney c ame f rom t he usual loc at ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2676

18 - The Kidney and Ureter Renal agenesis is ext remely rare, and bilat eral renal agenesis is let hal. T he prev alenc e of bilat eral renal agenesis and unilat eral renal agenesis v aries by populat ion, but eac h oc c urs in less t han 5 c ases per 10,000 birt hs (100,484). T he lef t kidney is slight ly more of t en absent (127). Ot her genit ourinary abnormalit ies t hat may be assoc iat ed w it h unilat eral renal agenesis inv olv e absenc e of t he seminal v esic les, v as def erens, or epididy mis in males and ut erine, t ubal, or v aginal anomalies in f emales (127). In pat ient s w ho hav e

renal agenesis or loss of t he kidney during c hildhood, t he remaining kidney w ill of t en enlarge; t his proc ess is know n as c ompensat ory renal hy pert rophy . Af t er nephrec t omy , t he remaining kidney v olume c an enlarge t o a relat iv e v olume of approximat ely 120% w it hin 3 y ears (491) (F ig. 18- 11). T he hy pert rophied kidney usually w ill ret ain a normal loc at ion and orient at ion.

Abnormal Cortical Appearance In a normally loc at ed kidney , anot her t y pe of renal v ariant is v isualized as an anomalous t hic kened appearanc e of t he renal c ort ex, t ermed c olumn of Bert in (F ig. 18- 12). T his prominent area of renal c ort ex may simulat e a t umor, but it is of t en assoc iat ed w it h a single c ent ral py ramid, w hic h may suggest t he diagnosis. Alt hough t he st ruc t ure may appear hy poec hoic on ult rasound and require addit ional imaging, t he lesion usually has at t enuat ion and enhanc ement pat t erns similar t o t he rest of t he renal parenc hy ma on CT and MRI. A c lue t o t he diagnosis is t he ext ernal margin of t he kidney should be smoot h, and any dist ort ion of t he c ort ic al margin should suggest an alt ernat iv e diagnosis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2677

18 - The Kidney and Ureter

F igure 18- 11 Compensat ory hy pert rophy of t he lef t kidney af t er nephrec t omy . Oblique c oronal v olume rendered image f rom a CT angiogram show s an enlarged lef t kidney and absent right kidney .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2678

18 - The Kidney and Ureter

F igure 18- 12 Prominent c olumn of Bert in. Axial images of t he lef t kidney f rom a mult iphase renal CT rev eals a prominent region of renal c ort ex (ar r ow s) ext ending int o t he renal hilum on c ort ic omedullary phase (A) and nephrographic phase (B).

A junc t ional c ort ic al def ec t is a c ommon v ariant ident if ied on ult rasound t hat has been suggest ed t o represent an embry onic f usion def ec t (518). T his v ariant is demonst rat ed as a f oc al area of c ort ic al t hinning at t he ant erosuperior or post erior inf erior margin of t he kidney . It is usually loc at ed bet w een t he low er pole and mid- port ion at t he junc t ions of renunc uli (68). A linear c ort ic al st ruc t ure, know n as an int ermediat e sept um, is c ommonly assoc iat ed w it h a junc t ional c ort ic al def ec t (518). T he enhanc ement pat t ern on CT and MRI dif f erent iat e t his normal v ariant f rom a t umor. How ev er, t he appearanc e of a junc t ional def ec t may simulat e c ort ic al sc arring. P.1242 A renal pseudot umor may also oc c ur at t he ant erior aspec t of t he renal c ort ex. T his has been t ermed as a hilar lip. T his t hic kened region of c ort ex may be prominent on ult rasound, and it may ev en appear slight ly hy poec hoic t o t he adjac ent parenc hy ma. How ev er on CT or MRI, t he c harac t erist ic s are similar t o t he rest of t he parenc hy ma on all sequenc es.

RENAL CALCIFIC DISEASE Renal Stones Whereas ev aluat ion of suspec t ed urinary lit hiasis has relied on radiologic imaging f or many y ears, t he imaging done t radit ionally w as c onv ent ional x- ray radiographs w het her w it hout or w it h int rav enous iodinat ed c ont rast . F or most of t he 20t h c ent ury , ev en f or many y ears af t er CT w as c ommonly av ailable, t he int rav enous urogram (IVU) w as c onsidered t he st andard f or suc h ev aluat ions. How ev er, in t he 10 y ears sinc e t he landmark f irst report ed use of nonc ont rast CT f or det ec t ion of urinary c alc uli (472), CT has bec ome t he st andard in t he Unit ed St at es, v irt ually replac ing t he IVU. Wit h it s c urrent ly rec ognized adv ant ages of rapid, ac c urat e diagnosis w it h minimal risk, one may w onder w hy it t ook so long af t er av ailabilit y of CT f or t his t ransit ion t o oc c ur. T he answ ers largely are, f irst , t radit ion, t he ac c ept anc e of t he usef ulness of t he IVU; sec ond, t he major c ost dif f erent ial espec ially in earlier day s; and t hird, t he great er limit at ion of CT bef ore t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2679

18 - The Kidney and Ureter

adv ent of rapid spiral CT t ec hnology as w ell as w ider penet rat ion of CT in t he medic al c are env ironment . F rom t he init ial report s (472,473), c onf irmed by numerous independent inv est igat ors (78,150,368), unsurpassed ac c urac y w as demonst rat ed f or nonc ont rast CT , w it h a sensit iv it y 97% t o 100% and spec if ic it y 92% t o 100%. T o emphasize t he usef ulness of CT , it has been show n t hat alt hough nearly all c alc uli c an be det ec t ed w it h CT , only about 60% are rec ognizable on c onv ent ional radiographs (298). CT has been show n t o be more rapid and ac c urat e t han eit her t he IVU or sonography (US). A number of st udies hav e c ompared CT w it h US alone or in c ombinat ion w it h plain radiographs (73,156,454,519). T he sensit iv it y of US ranged f rom 24% t o 77% v ersus 92% t o 96% f or CT , w hic h also prov ided muc h more rapid result s. A c onsiderable adv ant age of CT is t he abilit y t o det ec t nonc alc if ic genit ourinary (GU) pat hology as w ell as non- GU abnormalit ies, w hic h may be t he c ause of sy mpt oms. T he c apabilit y of t he IVU f or t his is ext remely limit ed, and alt hough sonography may demonst rat e gy nec ologic pat hology , it is less c apable of demonst rat ing gast roint est inal pat hology suc h as div ert ic ulit is, appendic it is, mesent eric adenit is, and panc reat it is, et c . In t he 210 pat ient s Smit h st udied (474), 30 w ere f ound w it h alt ernat e diagnoses ot her t han st ones. Nonst one GU pat hology in 14% and nongenit ourinary lesions in 11% w ere report ed by F ielding (150). Some hav e report ed “ indic at ion c reep” ov er t he y ears (79,147), and dec rease in posit iv e rat e (obst ruc t ing st one in uret er) f rom 49% t o 28% w it h c orresponding inc rease in alt ernat e diagnosis rat e f rom 16% t o 49% has been c onsidered a result of poor pat ient selec t ion (79). How ev er, one c ould argue t hat t his is of lit t le c onsequenc e if t he pat ient present ing w it h pain, of w hat ev er et iology , c omes t o rapid ac c urat e diagnosis by CT and prompt t reat ment . Alt hough some argued t hat t he IVU or ot her t est s w ere nec essary t o look f or ev idenc e of t he degree of obst ruc t ion, t his argument has f allen out of f av or. Many of t he sec ondary signs on CT are in f ac t a result of t he phy siology of obst ruc t ion. More import ant , t he presenc e or degree of obst ruc t ion does not signif ic ant ly inf luenc e out c ome or management . T he size of t he st one and t he pat ient 's sy mpt oms are most c rit ic al, and it has been demonst rat ed t hat CT measurement of st one size is ac c urat e (378).

Technique

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2680

18 - The Kidney and Ureter No c ont rast is administ ered, t hus no preparat ion is needed. Af t er a sc out v iew , sc anning should inc lude f rom at least just abov e t he upper pole of kidney s (if not lung base) t o perineum, and should be done in a single ac quisit ion suc h t hat sc rolling is c ont inuous w it hout pause or a gap. T y pic al paramet ers inc lude 120- t o 140- kilov olt (peak) (kV(p)) w it h 5- mm c ollimat ion and pit c h 1.5:1. It may be possible t hat det ec t ion of t iny st ones is bet t er w it h pit c h 1:1 or 2.5 mm c ollimat ion, or bot h, but t his is not rout inely nec essary . If t here is any quest ion about t he c linic al suspic ion, it is a good

prac t ic e f or a radiologist t o assess t he images bef ore releasing t he pat ient . If t here are unsuspec t ed f indings, or a quest ion as t o w het her a densit y lies in t he uret er or not , or espec ially if t he ref erring c linic ian has indic at ed c onc ern about ot her diagnoses if no st one is det ec t ed, t he radiologist c an t hen make t he dec ision w het her t o proc eed w it h a c ont rast ed st udy . T he radiologist may also ask f or a prone series t o dif f erent iat e a st one t hat may lie in t he bladder (usually ly ing at midline) but possibly in uret eral orif ic e (more lat eral) (F ig. 1813). In t he experienc e at t he aut hor's inst it ut ion, approximat ely 12% of st udies proc eed t o c ont rast , alt hough t he ac t ual f requenc y v aries w it h t he experienc e of t he radiologist and t he ast ut eness of t he ref erring c linic ian. If c ont rast is giv en merely t o opac if y t he uret er, t he dose c an be limit ed t o 50 mL, and an appropriat e delay (4 t o 5 minut es) bef ore sc anning should be allow ed. If a st one is ident if ied in t he uret er on t he CT and is ov er 4 mm or 300 HU but not v isible on t he sc out v iew , it may be helpf ul t o obt ain a c onv ent ional abdominal radiograph t o f ollow t he st one (565).

Interpretation Int erpret at ion is best done “ sof t c opy ” by sc rolling sequent ially t hrough t he images on a w orkst at ion. T his improv es P.1243 t he abilit y t o f ollow t he uret er ev en if it is nondilat ed as it c ourses c audally ant erior t o t he psoas musc le, init ially lat eral t o t he ipsilat eral gonadal v ein, c rossing medial t o gonadal v ein in t he low er abdomen, t hrough middle of t he pelv is, and t hen ant eriorly t o t he t rigone (F ig. 18- 14). T his is most import ant bec ause t he key f inding is t hat of a high at t enuat ion st ruc t ure w it hin t he uret er. A c ommon (50% t o 77%) (29,30) c onf irmat ory f inding is t he sof t t issue rim 1- t o 2- mm t hic kening around t he st one result s f rom edema of t he uret eral w all (F ig. 18- 15), w it h a spec if ic it y of 92% (201).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2681

18 - The Kidney and Ureter

F igure 18- 13 St one lodged at t he uret erov esic le junc t ion (UVJ). Supine (A) and prone (B) images f rom a nonc ont rast ed CT w it h a uret eral c alc ulus at t he UVJ apparent ly in t he bladder. Prone image w it h t he st one in a nondependent posit ion c onf irms t he st one has not y et passed.

Dist inguishing a st one f rom a phlebolit h is a c ommon c hallenge, espec ially in t he low pelv is if t he uret er is nondilat ed. Sev eral f eat ures may help in t his dist inc t ion: phlebolit hs are alw ay s smoot h and round; st ones of t en are angular and may hav e f uzzy edges. Phlebolit hs rarely (0% t o 20%) demonst rat e a sof t t issue rim sign (27,201,254). A sof t t issue ext ension f rom a phlebolit h is seen oc c asionally (21%) looking somew hat like a c omet t ail (F ig. 18- 16) and represent ing t he residual v ein; t his is not seen w it h a st one in t he uret er (45). A c ent ral luc enc y is c ommonly (but not inv ariably ) seen w it h phlebolit hs (somet imes requiring bone w indow set t ings) but is rare in st ones. Comparison w it h prev ious st udies c an be illuminat ing—phlebolit hs remain in t he same posit ions; if a prior st udy show ed no densit y in a loc at ion of a c urrent c alc if ic at ion, it probably is not a phlebolit h. Phlebolit hs in t he gonadal v ein c an be mist aken f or st ones if one is unf amiliar w it h t heir oc c urrenc e and t he c ourse of t he gonadal v ein. Alt hough giv ing c ont rast t oo f requent ly is t o be av oided, it may be nec essary .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2682

18 - The Kidney and Ureter

F igure 18- 14 Normal c ourse of t he uret ers. Coronal rec onst ruc t ions of exc ret ory phase CT U show s t he proximal uret ers c oursing f rom t he medial aspec t s of t he kidney s int o t he pelv is. Not e t hat t here is mild elev at ion of t he bladder w it h horizont al pat h of t he dist al uret ers likely due t o prost at e enlargement .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2683

18 - The Kidney and Ureter F igure 18- 15 Sof t t issue rim surrounding c alc ulus. Nonc ont rast CT demonst rat es a f oc al c alc if ic at ion (arrow ) in t he proximal uret er w it h a

c onc ent ric rim of sof t t issue densit y , indic at ing an impac t ed uret eral c alc ulus. Not e t hat t here is also mild perinephric st randing, suggest ing mild urinary obst ruc t ion.

P.1244 Giv ing c ont rast t o hav e absolut e c ert aint y is bet t er t han leav ing t he c linic ian unsure w het her t he pat ient has a st one or not , leading t o unnec essary f ollow up. T he obst ruc t ion result ing f rom a st one lodged in t he uret er c auses sec ondary signs (473). T hese inc lude: hy dronephrosis (69%) uret eral dilat at ion (67%), perinephric st randing (65%) periuret eral st randing (65%) and sw elling of t he kidney (251). Det ec t ion of t he sec ondary signs alone makes presenc e of a uret eral c alc ulus as likely as 99% (473). Sec ondary signs, how ev er, hav e t heir limit at ions bec ause t hey are rat her subjec t iv e. Absenc e of sec ondary signs does not by any means exc lude a st one. Hy dronephrosis c an be ov erc alled due t o ext rarenal pelv is; assessment of t he c aly c es at t he poles is more reliable t han t he pelv is. Uret ers c an be dilat ed bec ause of diureses, ref lux, or prior obst ruc t ion. Perinephric st randing c an be seen f or many reasons; if bilat erally sy mmet ric it is likely unimport ant . When t here is obst ruc t ion, inc reased ly mphat ic f low f rom t he kidney , redirec t ed t o t he c apsular ly mphat ic s due t o t he peripelv ic pressure, produc es t his st randing (528). F rank perinephric f luid c an be seen; at least some of t he t ime t his is ac t ual c aly c eal rupt ure, and administ rat ion of c ont rast w ill show ext rav asat ion (F ig. 18- 17). T he renal edema also c auses t he loss of t he hy perdense py ramid c ommonly seen in slight ly dehy drat ed kidney s. It has been show n t hat obst ruc t ed kidney parenc hy ma measures 5- 14 HU less t han normal (172). It has been report ed t hat t he presenc e and sev erit y of sec ondary signs c orrelat es w it h degree of obst ruc t ion on IVU (44). It makes int uit iv e sense t hat t he durat ion of sy mpt oms c orrelat es also w it h sev erit y of sec ondary signs (528). In any c ase, t hese signs hav e not reliably been show n t o c orrelat e w it h out c ome and t hus c annot direc t management . St one size and posit ion hav e c onsist ent ly been show n t o be t he most reliable predic t ors of out c ome. Approximat ely 90% of 1mm st ones w ill pass, proximal st ones 5 mm or larger rarely pass; only 50% of st ones larger t han 7 mm pass, but some sizable dist al st ones may pass spont aneously (95,403). Most uret eral st ones larger t han 6 mm undergo int erv ent ion (149).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2684

18 - The Kidney and Ureter

F igure 18- 16 Comet t ail adjac ent t o phlebolit h. Unenhanc ed CT of t he pelv is show s a phlebolit h on t he right w it h asy mmet ric “ c omet t ail” sof t t issue densit y (ar r ow head). A st one in t he dist al lef t uret er (arrow ) is also present .

When c onserv at iv e management is inst it ut ed, f ollow - up of t he st one must be done. If a st one is c learly v isible on sc out v iew , it should be v isible on c onv ent ional radiograph. How ev er, less t han 50% of st ones are v isible on sc out v iew , but up t o 60% c an be seen on c onv ent ional radiograph. Nearly all c alc uli larger t han 5 mm or great er t han 300 HU w ill be radiographic ally v isible, but t hose less t han 2 mm or less t han 200 HU may need t o be f ollow ed w it h CT (565).

Pitfalls St ones c omprised of c onc ret ions of prot ease inhibit or c ry st als are not readily demonst rat ed as high at t enuat ion lesions on CT . How ev er, presumed diagnosis may be made in pat ient s on t his medic at ion w it h sy mpt oms of c olic and sec ondary signs on CT . Sev eral pot ent ially signif ic ant nonst one GU diseases c an c ause pain but require c ont rast f or diagnosis, inc luding py elonephrit is, renal inf arc t ion, t rauma, and renal t umors. F urt hermore, diseases t hat do not relat e t o t he genit ourinary sy st em are of t en undet ec t ed w it hout int rav enous or oral c ont rast . T here has been some c ont rov ersy regarding radiat ion exposure f rom CT f or st ones. T here is c omparable radiat ion dose t o t he pat ient f or single- series CT c ompared w it h IVU (147), but t he relat iv e risk depends on t he t ec hnique of eac h examinat ion. How ev er, f requent repeat

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2685

18 - The Kidney and Ureter examinat ions and f ollow - up w it h CT c an inc rease t he pat ient dose dramat ic ally .

F igure 18- 17 Py elosinus rupt ure. Delay ed CT images af t er int rav enous c ont rast show ext rav asat ion of dense c ont rast - c ont aining urine (A) due t o bac kf low sec ondary t o obst ruc t ion f rom dist al uret eral st one (B).

P.1245 Whic h met hod is best f or diagnosis of urinary lit hiasis in pregnant w omen is c ont rov ersial. At t he aut hors' inst it ut ion, if sonography is not def init iv e and t he pat ient 's sy mpt oms are st rongly suspic ious, nonc ont rast CT is perf ormed. T he radiat ion dose is c ont rolled by init ially perf orming a single t est slic e at t he t hic kest part of t he upper abdomen w it h dose reduc ed t o t he low est lev el prov iding adequat e image qualit y (usually 80 t o 100mA maint aining kV at 120 t o 140) and t hen proc eeding w it h t he st udy w it h t hose paramet ers t o ensure rapid and ac c urat e diagnosis on one st udy . Inc reasing t he pit c h t o 2 also reduc es t he dose. Bec ause of it s high c ont rast sensit iv it y , CT allow s dif f erent iat ion of t issues w it h muc h less at t enuat ion dif f erenc e t han c an be ident if ied w it h radiography ; t hus, t here is great er sensit iv it y f or det ec t ion of small or f aint c alc if ic at ions t han is possible w it h radiography . Alt hough t here is lit t le published dat a, it is our experienc e t hat CT demonst rat es more c alc uli in st one f ormers t han does sonography (unpublished dat a), and CT is also muc h more sensit iv e t han MRI. In t he hands of a radiologist w ho is f amiliar w it h pat t erns of c alc if ic at ion, t his sensit iv it y , c ombined w it h t he prec ise loc alizat ion and appearanc e of t he c alc if ic at ion as w ell as ot her imaging f eat ures on CT , c ommonly allow s c orrec t diagnosis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2686

18 - The Kidney and Ureter T he normal kidney c ont ains no c alc if ic at ion; t hus, presenc e of c alc if ic at ion is alw ay s an indic at ion of disease, but a w ide range of disorders may result in renal c alc if ic at ion. Opt imal ev aluat ion of renal c alc if ic at ions requires bot h

unenhanc ed and c ont rast - enhanc ed images, bec ause c ollec t ing sy st em c alc uli may be obsc ured by c ont rast and bec ause diagnosis of c alc if ied renal t umors rest s more on presenc e or absenc e of lesional enhanc ement t han presenc e or absenc e of c alc if ic at ion (235). Nephrolit hiasis, t hat is, f ormat ion of st ones in t he c ollec t ing sy st em, is one of t he most c ommon c auses of c alc if ic at ions in t he urinary t rac t . Alt hough t he CT at t enuat ion is higher in st ones w it h a signif ic ant c alc ium c omponent , all c ommonly seen urinary st ones, inc luding urat e and c y st eine st ones (w it h t he exc ept ion of prot ease inhibit or c onc ret ions) (36), are “ w hit e” on CT images w it h usual sof t t issue w indow and lev el set t ings. A c rit ic al f ac t or in disc riminat ing nephrolit hiasis f rom ot her c ondit ions is rec ognizing t hat t he c alc uli lie only w it hin t he c ollec t ing sy st em. Nephroc alc inosis most c ommonly result s in c alc if ic at ions w it hin t he medullary regions or w it hin c ort ex depending on c ause. In some pat ient s, and part ic ularly in pat ient s w it h medullary sponge kidney , mult iple f ine medullary c alc if ic at ions may be present in addit ion t o c ollec t ing sy st em st ones. Wit h v ery high resolut ion (1.25 mm or less) mult idet ec t or CT it may be possible t o demonst rat e also t he “ paint brush” appearanc e of t he dilat ed medullary t ubules of MSK af t er c ont rast (241), similar t o IVU. Wit h medullary nephroc alc inosis, t he t y pic al appearanc e is t hat of mult iple small c alc if ic at ions in numerous py ramids in bot h kidney s (F igs. 18- 18 and 18- 19). Cort ic al nephroc alc inosis may be seen as amorphous c alc if ic at ion limit ed t o t he c ort ex w it h sparing of medulla, c alc if ic at ion in bot h c ort ex and medulla, or w it h c hronic c ort ic al nec rosis “ t ram- line” c alc if ic at ion on t he periphery and c ort ic omedullary junc t ion (305). Milk of c alc ium is w ell demonst rat ed on CT as a lay er of high- at t enuat ion mat erial usually w it hin a c y st ic st ruc t ure (most c ommonly a c aly c eal div ert ic ulum), somet imes in a hy dronephrot ic pelv is or uret eroc ele. Images delay ed sev eral minut es af t er c ont rast injec t ion may be nec essary t o demonst rat e c ommunic at ion of t he c aly c eal div ert ic ulum w it h t he c ollec t ing sy st em (F ig. 18- 20). T his c an be part ic ularly v aluable w hen only a small amount of c alc if ic at ion is present , bec ause t he lesion may mist akenly be desc ribed as a c omplex c y st , raising c onc ern f or pot ent ial malignanc y , w hereas c aly c eal div ert ic ula ev en w it h st ones of milk of c alc ium hav e not been report ed t o hav e inc reased risk of malignanc y .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2687

18 - The Kidney and Ureter

F igure 18- 18 Medullary sponge kidney . Unenhanc ed CT of t he kidney show s mult iple punc t at e c alc if ic at ions (ar r ow ) w it hin t he renal py ramids.

P.1246

CALCIFIED RENAL MASSES Calc if ic at ions may oc c ur in eit her benign or malignant renal masses (310)(549) (113). Approximat ely 25% t o 30% of RCCs c ont ain c alc if ic at ion on CT (34,566); less t han 1% of c y st s are c alc if ied on radiography . T he likelihood of c alc if ic at ion in RCC inc reases w it h size: only 3% of a series of RCCs less t han 3 c m in diamet er w ere c alc if ied (560), w hereas in anot her st udy 33% of RCCs larger t han 3 c m c ont ained c alc if ic at ion on CT (34). T he exac t loc at ion of t he c alc if ic at ion and ot her f eat ures of t he mass c an be show n by CT , so t hat in many c ases a def init iv e diagnosis c an be made (264,549). Whereas MRI may help t o ev aluat e suc h masses, it c annot demonst rat e c alc if ic at ion w ell, show ing only large c alc if ic at ions as a relat iv e signal v oid bec ause of t he low number of w at er prot ons.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2688

18 - The Kidney and Ureter

F igure 18- 19 Medullary nephroc alc inosis. Cont rast ed CT of t he kidney s demonst rat es a line of c alc if ic at ions (ar r ow s) w it hin t he medullary regions of bot h kidney s. No c ont rast exc ret ion has oc c urred on t his c ort ic omedullary phase st udy .

Calc if ied renal masses f all int o t hree groups: (a) sof t t issue masses c ont aining c alc if ic at ion; (b) predominant ly c y st ic masses w it h f oc al, mural, or sept al c alc if ic at ion; and (c ) indet erminat e masses. Alt hough t he presenc e of c alc if ic at ion in a mass has f or many y ears been c onsidered a sign raising t he c onc ern f or malignanc y (RCC being t he most c ommon c alc if ied renal mass) (113), it is probably not an independent risk f ac t or (235). More import ant t han t he presenc e of c alc if ic at ion is t he presenc e or absenc e of enhanc ing t issue w it hin t he lesion, w het her or not t here is signif ic ant c alc if ic at ion. CT is preeminent not only in det ec t ing and display ing t he loc at ion and appearanc e of t he c alc if ic at ion, but also f or det ec t ing enhanc ement . As an alt ernat iv e f or pat ient s w ho c annot rec eiv e iodinat ed c ont rast , MRI is ef f ec t iv e in det ec t ing or exc luding enhanc ement , w hic h is usef ul ev en if c alc if ic at ion is not w ell show n. Sonography is rarely usef ul f or ev aluat ing c alc if ied renal masses, and dense c y st w all c alc if ic at ion prev ent s t he sonographic int errogat ion of t he lesional c ont ent s. If CT show s c alc if ic at ion t o be limit ed t o t he w all or sept a of a c y st ic mass, and t he mass ot herw ise f ulf ills c rit eria f or a c y st (homogeneous w at erat t enuat ion c ont ent s, w it h no enhanc ing solid c omponent or t hic k w alls), a benign c alc if ied c y st c an be diagnosed w it h c onf idenc e. If t he c alc if ic at ion is v ery dense or t hic k, f ollow - up is suggest ed. Diagnosis of a c alc if ied t umor c an be made in t w o sit uat ions—w hen t he c alc if ic at ion is w it hin t he subst anc e of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2689

18 - The Kidney and Ureter an enhanc ing mass, or w hen t here is peripheral c alc if ic at ion but also an enhanc ing area of sof t t issue w it hin t he mass. A v ariet y of pat t erns of c alc if ic at ion are f ound in RCC, inc luding punc t at e, amorphous, linear, and

c urv ilinear, peripheral c alc if ic at ion. Indet erminat e c alc if ied lesions are t hose in w hic h t here is some ot her dist urbing f eat ure in addit ion t o c alc if ic at ion, suc h as high at t enuat ion or het erogeneous c ont ent s, t hic k w alls or sept at ions, or quest ionable enhanc ement . F ine sept al or mural c alc if ic at ion, w it hout ot her dist urbing f eat ures, in a c y st is most likely benign (Bosniak 2 c at egory ). Ext ensiv e, dense mural or sept al c alc if ic at ion w it h no enhanc ement should probably be f ollow ed, alt hough t heir likelihood of malignanc y is probably less t han 50% (t hus, more properly Bosniak 2F t han Bosniak 3). Calc if ic at ions w it h c y st s are part ic ularly c ommon in aut osomal dominant poly c y st ic kidney disease (ADPKD), but w hen f ound in t his ent it y should not be c onsidered w orrisome f or malignanc y , bec ause t here is no malignant predilec t ion in t his disease and t he c alc if ic at ions are usually t he result of prior int rac y st ic hemorrhage. Calc if ic at ion c an be seen in mult ic y st ic dy splast ic kidney (MCDK), part ic ularly in adult s, but is not seen in mult iloc ular c y st ic nephroma (MLCN). RCC is t he most c ommon c alc if ied enhanc ing mass, but ot her renal t umors may rarely c ont ain c alc if ic at ions, inc luding Wilms t umor, T CC, squamous c ell c arc inoma, and met ast ases (16,196,274). About 10% of renal sarc omas may c alc if y , but c alc if ic at ion is v irt ually nev er seen in renal ly mphoma. Alt hough rare, c alc if ic at ion has been report ed in bot h angiomy olipoma and onc oc y t oma.

F igure 18- 20 St ones in a c aly c eal div ert ic ulum. Cort ic omedullary phase CT show s dense c alc uli (ar r ow ) in t he kidney prior t o exc ret ion. On delay ed

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2690

18 - The Kidney and Ureter images, t he st ones are dif f ic ult t o disc ern f rom t he c ont rast w it hin t he c aly c eal div ert ic ulum.

P.1247

OTHER RENAL CALCIFICATIONS Inf lammat ory masses and hemat omas also may c alc if y . St aghorn c alc uli c an be w ell show n on CT (somet imes c orrelat ion w it h sc anned radiograph may be helpf ul t o be c ert ain of t he c ont iguous branc hed c onf igurat ion, indic at iv e of a st aghorn). CT c an also dist inguish t he f eat ures of xant hogranulomat ous py elonephrit is (XGP) f rom t hose c ases w it h st aghorn in a hy dronephrot ic or at rophic kidney . Hy dat id c y st s of t he kidney of t en are c alc if ied, and t hese may raise suspic ion of RCC bec ause hy dat id disease is unc ommon in t he Unit ed St at es. Det ec t ion of daught er c y st s suggest s t he diagnosis, bec ause c alc if ied RCC rarely is mult iloc ular (111). Calc if ic at ion is one f eat ure t hat may be seen in renal t uberc ulosis (T B), most of t en as c alc if ic at ion w it hin a parenc hy mal mass (t uberc uloma). Alt hough t his may raise w orry about renal c arc inoma, usually ot her f indings of T B are also present . Less c ommonly , c alc if ic at ion of urot helium (pelv is, uret er, or bladder) may result f rom T B. In immunoc ompromised pat ient s, part ic ularly t hose w it h AIDS, t iny mult if oc al renal c alc if ic at ions c an result f rom at y pic al my c obac t eria (my c obac t erium av ium int rac ellulare) or pneumoc y st is (343). A v ariet y of v asc ular diseases c an c ause renal c alc if ic at ion. T he most c ommon is at herosc lerosis, w hic h c auses c alc if ied art erial plaques, usually at renal art ery origins; t here may be ext ensiv e c alc if ic at ion ext ending int o int rarenal branc hes espec ially w it h c hronic renal f ailure. Renal art ery aneury sms and art eriov enous malf ormat ions may c alc if y . T he relat ionship of t he round, c alc if ied aneury sm w it h t he renal v asc ulat ure is usually w ell show n w it h CT , and c ont rast enhanc ed CT , espec ially w it h CT angiography t ec hniques, c an show t he v asc ular nat ure (as w ell as ot her f eat ures suc h as engorgement and early f illing of renal v ein w it h art eriov enous malf ormat ion (AVM)) t o allow c orrec t diagnosis. Old hemat omas may c alc if y ; most c ommonly seen is a lent ic ular subc apsular c alc if ied lesion ow ing t o a remot e subc apsular hemat oma; t here may be assoc iat ed residual dist ort ion of t he kidney .

CYSTIC RENAL DISEASE

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2691

18 - The Kidney and Ureter T he most c ommon renal mass in t he adult is a c y st . Simple renal c y st s arise f rom t he c ort ex. If a lesion f ulf ills all t he st ric t c rit eria f or a c y st on sonography or CT , no f urt her imaging ev aluat ion is needed. Diagnost ic

f eat ures of simple c y st s on CT are (a) smoot h, round shape; (b) homogeneous w at er- at t enuat ion f luid c ont ent ; (c ) smoot h, sharp int erf ac e w it h adjac ent renal parenc hy ma; and (d) imperc ept ible c y st w all (F ig. 18- 21). Somet imes on CT , a t hin rim of renal parenc hy ma may surround t he c y st (espec ially polar c y st s); also, t w o adjac ent c y st s may c ompress renal parenc hy ma bet w een t hem (F ig. 18- 22). Oc c asionally , a beak of renal parenc hy ma may be produc ed at t he margin bet w een c y st and kidney (446). If suc h masses ot herw ise f ulf ill CT c rit eria f or a c y st , t hey should not be pursued aggressiv ely . Alt hough a v ariet y of t ec hnic al f ac t ors af f ec t CT at t enuat ion numbers, t he lat t er c an nev ert heless be most usef ul in t he diagnosis of renal masses. Simple c y st s hav e homogeneous at t enuat ion similar t o t hat of w at er and should not hav e a at t enuat ion ov er 20 HU. T here should be P.1248 no signif ic ant inc rease in t he at t enuat ion af t er int rav enous c ont rast . How ev er, bec ause of v arious f ac t ors, inc luding v olume av eraging and beam hardening (due t o t he iodine c onc ent rat ed in t he adjac ent renal parenc hy ma on enhanc ed sc ans), an inc rease of less t han 10 HU should not be c onsidered diagnost ic of enhanc ement (46). Rec ent st udies hav e show n t hat an inc rease of 15 t o 20 HU may be more ac c urat e in pat ient s w it h bright enhanc ement of t he renal c ort ex (314). T his pseudoenhanc ement is more pronounc ed on mult idet ec t or CT t han on single slic e CT (202). T he c y st c ont ent s should also remain homogeneous af t er c ont rast . Ac c urat e assessment of enhanc ement requires appropriat e sec t ion t hic kness—t he slic e t hic kness should be no more t han half t he diamet er of t he mass. Volume av eraging may result in spurious “ enhanc ement ” w hen t he slic e inc ludes part of t he c y st and part of t he renal parenc hy ma, bec ause t he CT at t enuat ion v alue is an av erage of marked inc rease in at t enuat ion of a small port ion of renal parenc hy ma and t he nonenhanc ing c y st c ont ent s.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2692

18 - The Kidney and Ureter

F igure 18- 21 Simple c y st . Cont rast ed CT show s an exophy t ic c y st w it h low er at t enuat ion t han t he adjac ent renal parenc hy ma w it h no c omplexit y or perc ept ible w all.

F igure 18- 22 Pseudosept at ion. Cont rast ed CT show s mult iple adjac ent simple c y st s. T he t hin int erf ac e bet w een t w o adjac ent c y st s (ar r ow ) may simulat e sept at ion.

Cy st s may be solit ary or mult iple, and t hey c an arise any w here in t he kidney . T hey t end t o inc rease in size and number w it h age (112). Alt hough c y st grow t h is slow , inc rease in size w ill be seen w hen f ollow ed f or y ears. Cy st s are usually asy mpt omat ic . How ev er, t hey may c ause hemat uria, and, if large, t hey may c ause c ompressiv e mass ef f ec t , w hic h c an lead t o hy pert ension or obst ruc t ion of t he c ollec t ing sy st em. In suc h c irc umst anc es, c y st aspirat ion and sc lerosis, w hic h c an be done w it h CT or US guidanc e, is just if ied. Cy st aspirat ion c urrent ly has no role in diagnosis of c omplex c y st s.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2693

18 - The Kidney and Ureter Alt hough in general unnec essary , MRI demonst rat es a dist inc t iv e appearanc e of simple renal c y st s (250,320). Simple c y st s hav e t he same morphologic f eat ures on MRI as on CT : t hey are round and homogeneous, w it h a smoot h, sharp int erf ac e w it h renal parenc hy ma and an imperc ept ible w all. T heir signal int ensit y mirrors t hat of w at er (or c erebral spinal f luid); t hey are v ery

hy point ense on T 1- w eight ed images, and t hey are v ery hy perint ense (bright er t han f at ) on T 2- w eight ed images (F ig. 18- 23). No c y st enhanc ement w ill oc c ur af t er int rav enous Gd- DT PA (alt hough v olume av eraging also oc c urs w it h MRI, and signal int ensit y numbers are not st andardized, so no absolut e numeric al c rit eria c an be used). Caly c eal div ert ic ula may be disc ov ered on CT as inc ident al f indings, and on oc c asion t hey are imaged f or f urt her c harac t erizat ion af t er sonography , bec ause t hese lesions may appear c omplic at ed, w it h c alc uli, debris, or milk of c alc ium w it hin t he div ert ic ulum. T hese c y st ic spac es are lined by t ransit ional epit helium and c ommunic at e w it h t he c ollec t ing sy st em t hrough a narrow opening. T hey are c ommonly small and int rarenal, but t hey may be large and ext end t o t he surf ac e of t he kidney (F ig. 18- 24). T hey measure w at er at t enuat ion on prec ont rast images unless c alc uli or milk of c alc ium is present . T he lat t er is seen as a lay ered high at t enuat ion, w hic h w ill shif t w it h c hange in pat ient posit ion (495). On art erial phase, or rout ine P.1249 early nephrographic CT images, a c aly c eal div ert ic ulum w ill usually show w at er at t enuat ion and may be misdiagnosed as c omplic at ed c y st if c alc if ic at ion is present . Exc ret ory phase images (4 t o 8 minut es af t er c ont rast administ rat ion) w ill show some f illing w it h c ont rast in most c ases, allow ing c orrec t diagnosis (F ig. 18- 24B).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2694

18 - The Kidney and Ureter

F igure 18- 23 Simple c y st . Axial T 2- w eight ed MRI image demonst rat es homogenous high signal, c onsist ent w it h f luid, in a simple lef t renal c y st .

F igure 18- 24 Lay ering c ont rast in c aly c eal div ert ic ulum. A: Nephrographic phase CT show s a c ort ic al hy podensit y t hat is nonspec if ic . B: On delay ed image, t here is lay er of exc ret ed c ont rast (arrow ), c onf irming a c aly c eal div ert ic ulum.

A v ariet y of c omplex or c omplic at ed c y st ic masses oc c ur, most of w hic h are benign and of no c linic al c onsequenc e. Nonet heless, t hey must be dist inguished f rom renal malignanc y (104,105). CT and MRI are v ery usef ul f or t his purpose, w it h CT play ing t he primary imaging role. A simple c y st may bec ome c omplic at ed as a result of hemorrhage, inf ec t ion, or ot her proc esses t hat t hic ken some or t he ent ire w all and may inc rease t he at t enuat ion of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2695

18 - The Kidney and Ureter c ont ent s (46,194,425). Calc if ic at ion w it hin t he w all or a sept um may oc c ur (105) (F ig. 18- 25). Ac ut e bleeding int o a c y st may present w it h pain, and a f luid lev el may be seen w it hin an ac ut ely hemorrhagic c y st . T he c y st may show inc rease in size on serial st udies. Hy perdense c y st s hav e an at t enuat ion v alue great er t han renal parenc hy ma on prec ont rast CT images, c ommonly measuring 40 t o 90 HU (46,93,101,197,569) (F ig. 18- 26). T his may be a result of bleeding int o t he c y st , w it h c onc ent rat ion of t he prot ein c omponent s of blood. Some of t hese c y st s c ont ain a mat erial as t hic k and dark as c rankc ase oil, and ot hers c ont ain inspissat ed w hit e mat erial (similar t o milk of c alc ium), but some hav e c lear amber f luid w it h a high prot ein c ont ent (152,493). Most hy perdense c y st s are solit ary , but t hey may be mult iple; t hey are quit e c ommon in aut osomal dominant poly c y st ic disease (292). Hy perdense c y st s may appear sonoluc ent , but in many c ases sonography show s int ernal ec hoes bec ause of t he t hic k nat ure of t he c ont ent s. If t he lesion is small (most are less t han 3

c m), homogeneous, and show s no enhanc ement on post c ont rast images, and if it has no ot her c omplic at ing f ac t or (suc h as c alc if ic at ion), diagnosis of benign hy perdense c y st c an be made. If CT f irst det ec t s a hy perdense lesion, sonography may be helpf ul, bec ause it may c onf irm t he c y st ic nat ure. F ollow up of hy perdense c y st s (w it h t he exc ept ion of t hose in poly c y st ic disease) is prudent t o c onf irm t heir benign nat ure, bec ause, rarely , renal c arc inoma may hav e t he appearanc e of a hy perdense c y st (129,197). Sev eral ot her f indings may oc c ur in c y st ic lesions t hat raise t he lev el of suspic ion f or c arc inoma. T hic kening or irregularit y of t he w all, het erogeneit y of t he c ont ent s, c alc if ic at ion in t he w all, and mult iloc ularit y or sept at ion are all f indings t hat may be seen in benign c y st ic lesions but also c an be f ound in c y st ic renal neoplasms, inc luding renal c ell c arc inoma, Wilms t umor, and ot hers (104,195,194,425). Bosniak has desc ribed a c lassif ic at ion of renal c y st ic masses t hat is usef ul in c larif y ing t he risk of malignanc y and aids in t he management of c omplic at ed c y st ic lesions (46). T his c lassif ic at ion is largely based on CT f indings, but it inc ludes inf ormat ion f rom sonography , MRI, and f ollow - up. T his w ill be disc ussed f urt her in t he malignanc y sec t ion. Magnet ic resonanc e imaging c an be usef ul in ev aluat ing c omplic at ed renal masses. T he same morphologic c rit eria (e.g., homogeneit y , sharp marginat ion, t hic kness of w all and sept a) c an be used, as w it h CT . In addit ion, t he great sensit iv it y of MRI t o t issue c harac t erist ic s c an be usef ul bec ause hemorrhage or ot her alt erat ion of t he c y st c ont ent s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2696

18 - The Kidney and Ureter P.1250 w ill be ref lec t ed by het erogeneit y and c hange in t he signal c harac t erist ic s. Complic at ed c y st s hav e higher signal int ensit y t han w at er on T 1- w eight ed images, and t hey demonst rat e v ariable int ensit y on T 2- w eight ed images (F ig.

18- 27). If MRI show s a t y pic al simple c y st (homogeneous low signal on T 1 and high signal on T 2), neoplasm is ef f ec t iv ely exc luded (320). How ev er, w hen using only unenhanc ed T 1- and T 2- w eight ed images, c omplic at ed c y st s c annot be reliably dist inguished f rom renal neoplasms (224,320). T he av ailabilit y of MRI c ont rast agent s prov ides t he opport unit y t o det ermine enhanc ement . As w it h CT , c y st s do not enhanc e, but bot h benign and malignant neoplasms exhibit enhanc ement on post gandolinium st udies. MRI is equiv alent t o CT f or dist inc t ion of c y st s f rom neoplasms (423,452), and c urrent ly it is t he pref erred proc edure t o ev aluat e c omplic at ed c y st s in pat ient s w ho c annot t olerat e iodinat ed c ont rast . T o c learly rec ognize enhanc ement , how ev er, c aref ul c omparison of t he appearanc e of t he mass on t he same t y pe of sequenc e bef ore and af t er Gd- DT PA is needed, bec ause c omplic at ed c y st s are t y pic ally hy perint ense on T 1- w eight ed images. Ot herw ise, suc h hy perint ensit y may be misc onst rued as enhanc ement (449). As st at ed prev iously , it is easier t o apprec iat e subt le c ont rast enhanc ement on f at - suppressed images t han on non–f at - suppressed images.

F igure 18- 25 Benign c y st s w it h t hin (A) and t hic k (B) mural c alc if ic at ions. T w o images of a pat ient w it h mult iple c omplex renal c y st s show v ary ing degrees of w all c alc if ic at ion. St abilit y ov er t ime c onf irmed benignit y .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2697

18 - The Kidney and Ureter

F igure 18- 26 Hy perdense c y st s. Cont rast ed CT show s a mildly hy perdense exophy t ic right renal c y st (ar r ow ) w it hout perc ept ible w all or solid c omponent . T here w as no c hange in size ov er a t hree- y ear period.

PARAPELVIC CYSTS Nonc ort ic al c y st s oc c ur adjac ent t o t he renal parenc hy ma. Most c y st s seen in t he renal hilar region are believ ed t o be of ly mphat ic origin and are usually c alled parapelv ic c y st s bec ause of t heir loc at ion. T hese may be solit ary but f requent ly are mult iple. Et iology of t his t y pe of c y st is obsc ure, but no heredit ary pat t ern is know n. Suc h c y st s t y pic ally replac e t he renal sinus f at and displac e or c ompress adjac ent st ruc t ures, inc luding renal parenc hy ma, pelv is, and hilar v essels. When solit ary , t hese c y st s are larger, of t en sev eral c ent imet ers in size, and appear round or ov al. When mult iple, t hey are usually smaller, and t hey may be ov oid or lobulat ed (F ig. 18- 28). Parapelv ic c y st s are most P.1251 of t en of w at er at t enuat ion but may be somew hat higher at t enuat ion. T here is neit her enhanc ement nor c ommunic at ion w it h t he c ollec t ing sy st em af t er c ont rast medium administ rat ion (alt hough inc rease in at t enuat ion af t er ret rograde py elography has been report ed, presumably due t o ext rav asat ion and c ommunic at ion) (325). On unenhanc ed CT , MRI, or sonography , t hey may simulat e hy dronephrosis. How ev er, t heir t rue nat ure is obv ious on c ont rast enhanc ed CT , as t he c ont rast - f illed inf undibula are seen, ef f ac ed or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2698

18 - The Kidney and Ureter c ompressed by t he parapelv ic c y st (s) (see F ig. 18- 28). T hese lesions are of no c linic al signif ic anc e unless t hey enlarge enough t o c ause obst ruc t iv e uropat hy . Some of t hese c y st s are t hought t o dev elop as a result of prior obst ruc t ion w it h result ant urine ext rav asat ion, t he so- c alled parapelv ic urinif erous pseudoc y st s (199,348).

F igure 18- 27 Complex renal c y st . A: Coronal Axial T 2- w eight ed MRI show s c omplex renal c y st s (ar r ow ) among w it h subt le int ermediat e int ensit y among numerous simple ot her renal c y st s in a pat ient w it h PCKD. B: On unenhanc ed T 1- w eight ed images, t he c omplex c y st s hav ec y st has high signal relat iv e t o ot her c y st s. C : On c ont rast ed T 2- w eight ed images, t he c omplex c y st does not enhanc e (c urv ed arrow )s hav e low signal int ensit y , possibly due t o hemoglobin f rom prior hemorrhage.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2699

18 - The Kidney and Ureter

F igure 18- 28 Parapelv ic c y st s. Exc ret ory phase CT show s mult iple f luid densit y c y st s (ar r ow s) w it hin t he renal pelv is. T here is no c ommunic at ion w it h t he mildly st ret c hed c ollec t ing sy st ems, w hic h c ont ain dense exc ret ed c ont rast .

P.1252

CYSTIC DISEASES Autosomal Dominant Polycystic Kidney Disease Aut osomal dominant poly c y st ic kidney disease (ADPCKD) is a heredit ary disorder t hat af f ec t s mult iple organ sy st ems; it has 100% penet ranc e but v ariable expressiv it y . In most pat ient s (PKD1), t he disease result s f rom a genet ic lesion on t he short arm of c hromosome 16 (383). Anot her slight ly milder f orm of t he disease has been show n t o hav e a relat ed but dist inc t genet ic loc us on c hromosome 4 (PKD2). Renal disease is t he predominant c linic al f eat ure, w it h bet w een 5% and 10% of all end- st age renal disease result ing f rom ADPCKD, but t he proc ess af f ec t s many ot her organ sy st ems. Hy pert ension is v ery c ommon ev en bef ore t he onset of renal f ailure (157). Cerebral aneury sms oc c ur in 5% t o 10% (w it h c erebral hemorrhage oc c urring in about 8%), but t he sev erit y may be less t han prev iously c onsidered (442). T hese are usually small and inv olv e t he ant erior c irc ulat ion (164). Aort ic aneury sm, aort ic dissec t ion, and v alv ular heart disease are muc h more c ommon t han in t he general populat ion (212). Cy st s are f ound not only in t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2700

18 - The Kidney and Ureter kidney s but also in t he liv er in approximat ely 60% t o 80% of pat ient s (352).

T hey are present in t he panc reas in about 7% of pat ient s and in t he spleen in less t han 5% (212). Hepat ic f unc t ion is not usually impaired, how ev er, ev en w hen t he liv er is dif f usely inv olv ed. Aut osomal dominant poly c y st ic kidney disease present s in sev eral w ay s. T he av erage age of onset of renal f ailure is in t he sixt h t o sev ent h dec ade (157,212,383). Of t en t he diagnosis is made bec ause of sc reening, usually by sonography , of t he of f spring of an af f ec t ed indiv idual. Virt ually all pat ient s w it h t he disease hav e sonographic ally det ec t able c y st s by t he age of 30 y ears (383). Pat ient s may present w it h a palpable mass, bec ause t he kidney s bec ome enlarged w it h inc reasing number and size of c y st s. Not inf requent ly , pat ient s present w it h c omplic at ions of t he renal disease, inc luding f lank pain, hemat uria, or urinary t rac t inf ec t ion. Nephrolit hiasis (usually uric ac id c alc uli) has been report ed in up t o 36% of c ases (291). Alt hough CT and MRI are not usually indic at ed f or sc reening of suspec t ed subjec t s, t hey c an be usef ul f or ev aluat ion of c omplic at ions, and t hey bot h show t y pic al pat t erns t hat are v irt ually diagnost ic of t he disorder. Mult iple mac rosc opic c y st s ranging f rom a f ew millimet ers t o sev eral c ent imet ers are seen t hroughout t he f ull t hic kness of t he renal parenc hy ma (F ig. 18- 29) (281). Early in lif e, or in poorly penet rant f orms, only a f ew c y st s may be seen in t he kidney s, ov erlapping w it h t he appearanc e of mult iple sporadic simple c y st s. Det ec t ion of c y st s in ot her organs are a usef ul c lue t o t he diagnosis. Wit h progression, t he kidney s gradually enlarge as t he c y st s bec ome more numerous, bec ome larger, and replac e t he renal parenc hy ma (see F ig. 18- 29). Bilat eral inv olv ement is usual, but somet imes t he disease is quit e asy mmet ric , and, rarely , only one kidney show s signif ic ant disease (102,281,284,295). Alt hough t he c y st s may hav e t he t y pic al appearanc e of simple c y st s on CT , high- at t enuat ion c y st s are c ommon, result ing f rom t he f requenc y of hemorrhage int o t he c y st s (292). Only 31% of pat ient s in one st udy had no hy perdense c y st s (292). Calc if ic at ion of t he c y st w all is also c ommon, again most likely result ing f rom old hemorrhage. About 50% of ADPCKD pat ient s hav e c alc if ic at ions on CT , inc luding c alc if ied c y st s and renal c alc uli (291). Calc if ic at ion in t hese c y st s does not c arry t he same degree of c onc ern f or renal c arc inoma as it does in t he general populat ion. Alt hough t here is some c ont rov ersy , no public at ions hav e c onv inc ingly est ablished an inc reased inc idenc e of renal c ell c arc inoma (RCC) in ADPCKD. Nev ert heless, RCC does oc c ur in t hese pat ient s, and t he same diagnost ic c rit eria are used on CT as

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2701

18 - The Kidney and Ureter are used in general. T hus, it is v ery import ant t o assess enhanc ement w it h pre- and post c ont rast sc ans. Magnet ic resonanc e imaging may be used as an

alt ernat iv e if t here is a c onc ern ov er t he nephrot oxic it y of iodinat ed c ont rast . CT is v ery usef ul in ev aluat ing hemat uria in pat ient s w it h ADPCKD bec ause it c an det ec t c y st hemorrhage, c an dist inguish c alc uli f rom c y st c alc if ic at ion, and c an diagnose renal neoplasms w it h higher ac c urac y t han sonography c an.

F igure 18- 29 Aut osomal dominant poly c y st ic kidney disease. Cont rast ed CT image of t he kidney s demonst rat es dif f use c y st ic c hange in bot h kidney s w it h c y st s of v ary ing size and at t enuat ion.

Magnet ic resonanc e imaging may rev eal a c harac t erist ic pat t ern in pat ient s w it h ADPCKD. In addit ion t o enlargement of t he kidney s and t he presenc e of mult iple c y st s sc at t ered t hroughout t he parenc hy ma, almost inv ariably c y st s of v ary ing signal int ensit y appear on bot h T 1- and T 2- w eight ed images (F ig. 18- 30) (213). T his is a result of hemorrhage of v ary ing age w it hin t he c y st s, so t hat some c y st s are low signal on T 1- w eight ed images and high on T 2w eight ed images, w hereas ot hers hav e high signal on T 1- w eight ed images but remain low signal on T 2- w eight ed images. T he ef f ec t of hemorrhage int o c y st s is c omplex, but it may produc e short ening of bot h T 1 and T 2 v alues so, P.1253 t here may be inc reased signal on T 1 but dec reased on T 2, unlike in simple c y st s (213). Het erogeneit y and lay ering may be seen, ev en in some c y st s t hat are homogeneous on CT . Hemorrhagic c y st s of t en show lay ering, w it h t he dependent lay er hy perint ense on T 1- w eight ed images but hy point ense on T 2w eight ed images, and w it h t he nondependent lay er show ing t he rev erse

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2702

18 - The Kidney and Ureter pat t ern (428). Renal c arc inoma c an be det ec t ed on MRI in t hese pat ient s, as t he t umor enhanc es w it h int rav enous Gd- DT PA.

F igure 18- 30 Aut osomal dominant poly c y st ic kidney disease on MRI. A: T 2w eight ed c oronal image show s dif f use innumerable bright signal f rom innumerable c y st s inv olv ing bot h kidney s. B: On unc ont rast ed T 1- w eight ed image, t he lesions hav e low - t o- int ermediat e T 1- w eight ed signal. C : T here is no enhanc ement of t he c y st s on c ont rast ed T 1- w eight ed images, indic at ing lac k of enhanc ement .

Sonography is c ommonly used and ef f ec t iv e f or bot h sc reening and init ial diagnosis. Alt hough c urrent ly primarily a researc h int erest , v olumet ric ev aluat ion of ADPKD may be of v alue in assessing progression of disease, as renal f unc t ional paramet ers (suc h as serum c reat inine, glomerular f ilt rat ion rat e) do not w orsen unt il relat iv ely lat e in t he disease proc ess. Bot h CT (467) and MRI hav e been show n t o be usef ul in suc h ev aluat ion (76). T he ac c urac y of v olume measurement s of t ot al kidney v olume, t ot al c y st v olume and c hanges ov er t ime has been w ell est ablished (17). MRI has part ic ular adv ant ages bec ause of t he lac k of ionizing radiat ion and c ont rast w it h low

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2703

18 - The Kidney and Ureter renal t oxic it y , but it requires c aref ul ev aluat ion w it h mult iple series (T 1, T 2, and gadolinium- enhanc ed T 1) f or c omplet e assessment bec ause of t he v ariabilit y in c y st signal int ensit y .

Acquired Cystic Disease of the Kidney Nonheredit ary c y st ic disease of t he kidney (ACKD) is c ommon in any f orm of end- st age renal disease, but it is part ic ularly c ommon in pat ient s on c hronic hemodialy sis or perit oneal dialy sis (323). T he inc idenc e of ACKD ranges f rom 47% t o 87% (81,232,293), depending on t he durat ion of dialy sis, w it h an 80% likelihood report ed af t er t he t hird y ear (232). T he exac t et iology is not c ert ain; isc hemia, f ibrosis, unknow n met abolit es, and inadequat e c ont rol of renal disease hav e been post ulat ed as c auses. Hy perplasia of t ubular epit helium oc c urs, w hic h result s in bloc kage and dilat at ion of nephrons, leading t o c y st P.1254 f ormat ion. T here is a def init e inc rease in renal c arc inoma, w it h inc idenc es bet w een 5% and 19% report ed (81,161,230,232,293). T hus, rout ine ev aluat ion of pat ient s on dialy sis longer t han 3 y ears may be indic at ed.

F igure 18- 31 Ac quired c y st ic renal disease. A: Cont rast enhanc ed CT show s mult iple small c y st s in pat ient w it h end- st age renal disease. B: Cont rast ed CT in anot her pat ient show s marked enlargement of t he end- st age kidney by c ount less c y st s.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2704

18 - The Kidney and Ureter

Early in t he disease proc ess, t he kidney s are small w it h only a f ew c y st s (F ig. 18- 31). T he renal c ont our of t en is preserv ed, w it h most of t he c y st s small (less t han 0.5 c m) and c omplet ely int rarenal. Alt hough renal size may c ont inue t o dec rease t he f irst f ew y ears on dialy sis, ev ent ually t he renal size begins t o inc rease, as t he c y st s bec ome more numerous and larger (2 t o 3 c m). In a longit udinal CT st udy , 57% of pat ient s had some c y st s at t he beginning of dialy sis, w hereas 87% did af t er 7 y ears. During t his t ime, t he kidney v olume inc reased f rom 79 t o 150 c c (297). Hemorrhage c an oc c ur eit her int o t he c y st or int o t he subc apsular or perinephric spac e. T his c an c ause inc reased at t enuat ion, het erogeneit y , t hic kening, and c alc if ic at ion of t he c y st w alls. Ev ent ually , af t er many y ears of dialy sis, t he kidney s may ac hiev e an appearanc e nearly indist inguishable f rom t hat of ADPCKD (F ig. 18- 32), ev en w it h c alc if ic at ions (18). How ev er, c y st s do not oc c ur in ot her organs in ac quired disease. As w it h ADPCKD, CT is superior t o sonography f or det ec t ion of c omplic at ions, part ic ularly RCC (509). Prev alenc e of renal c arc inoma in hemodialy sis pat ient s has been report ed t o be as muc h as 40 t imes great er t han in t he general populat ion (502). Int rav enous c ont rast medium c an usually be used, if t he pat ient s already are on dialy sis, but MRI is also an ef f ec t iv e met hod f or diagnosis of RCC. Det ec t ion of an enhanc ing lesion on eit her CT or MRI is presumpt iv e ev idenc e of RCC (F ig. 18- 33). Alt hough a renal adenoma may be suggest ed if t he lesion is less t han 3 c m, P.1255 size is not a reliable c rit erion. How ev er, f ollow - up st udies hav e show n t hat a signif ic ant proport ion of RCC in ACKD pat ient s are relat iv ely indolent , 65% in one st udy hav ing ov er 1 y ear doubling t ime. If t he pat ient is not a good c andidat e f or nephrec t omy , or if t he lesion is less t han 2 c m, serial CT or MRI t o det ermine biologic aggressiv eness may be c onsidered.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2705

18 - The Kidney and Ureter

F igure 18- 32 Ac quired c y st ic renal disease (ACRD) mimic s poly c y st ic kidney disease (PCKD). A pat ient w it h sev ere ac quired c y st ic renal disease has c y st ic enlargement of t he kidney s simulat ing PCKD. ACRD is isolat ed t o t he kidney s, w hile t he presenc e of c y st s in t he liv er and panc reas w ould suggest PCKD.

F igure 18- 33 Small RCC in ACRD. Cont rast ed CT of t he right kidney in pat ient w it h ACRD demonst rat es a small f oc al enhanc ing mass (ar r ow s) w it h disrupt ion of t he c ort ic al margin. Pat ient s w it h ACRD are at elev at ed risk f or dev elopment of RCC.

Alt hough ACKD has been report ed t o regress af t er suc c essf ul renal t ransplant at ion (232), it has also been report ed t hat renal c arc inoma may oc c ur in nat iv e kidney s af t er t ransplant at ion (299). T he premalignant pot ent ial of t he c y st may remain f or some t ime, and inv est igat ion of t he nat iv e kidney s may be indic at ed in t ransplant pat ient s w it h hemat uria.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2706

18 - The Kidney and Ureter Autosomal Recessive Polycystic Kidney Disease Aut osomal rec essiv e poly c y st ic kidney disease, predominant ly inv olv ing renal

t ubular ec t asia and hepat ic f ibrosis, represent s only 10% of PCKD pat ient s and present s in inf anc y or c hildhood. It oc c urs in only 1 in 20,000 liv e birt hs (568). T he disease may present bef ore birt h, and inf ant s w it h t he disease do not t y pic ally surv iv e. Children w ho present w it h t he disease at a lat er age may surv iv e int o t heir t eens or early adult hood. T he most c ommon met hod of det ec t ion is by ult rasound bec ause of t he risks of radiat ion assoc iat ed w it h CT st udies in c hildren. On ult rasound, t he kidney s are usually sy mmet ric ally enlarged and may hav e c y st s or a dif f usely ec hogenic appearanc e (39,57). Disc ret e c y st s are not usually ident if ied on ant enat al sc reening ult rasound, det ec t ed in only 4 of 27 pat ient s in one st udy (57). On CT , t he kidney s are large and hy podense. T hey demonst rat e a st riat ed appearanc e of c ont rast enhanc ement (307). In a limit ed number of c ases, MRI c an det ec t early c y st ic lesions in t hese pat ient s as w ell. Biliary f ibrosis and manif est at ions of port al hy pert ension also oc c ur. MRI is also more sensit iv e f or biliary dilat at ion relat ed t o t he hepat ic manif est at ions of aut osomal rec essiv e PCKD t han is ult rasound or CT (245).

Tuberous Sclerosis T uberous sc lerosis (T S) is an aut osomal dominant heredit ary disorder result ing f rom a def ec t on c hromosome 9 (61). It has somew hat v ariable present at ion. Alt hough t he usual c linic al f eat ures are seizure disorder, ment al ret ardat ion, and c ut aneous lesions, pat ient s may not be rec ognized t o hav e t he disease unt il adult hood. Sev eral renal lesions hav e been assoc iat ed w it h T S, alt hough t he assoc iat ion w it h angiomy olipomas is best know n (179,437). Cy st s are seen in about 15% t o 45% of pat ient s, and c y st s may be present in t he f irst f ew mont hs of lif e in some pat ient s (69). Oc c asionally , numerous c y st s are present in a pat t ern similar t o t hat in ADPCKD (see F ig. 18- 27) (61)(344). Renal f ailure may oc c ur, but it is unc ommon. T hese c y st s hav e a hy perplast ic epit helial lining, as in ac quired c y st ic disease. T here may in f ac t be an inc reased inc idenc e of RCC in T S pat ient s, w it h an inc idenc e of 1% report ed (179,504). Angiomy olipomas (AMLs) oc c ur in 40% t o 80% of pat ient s w it h T S (526,399). Commonly , t hese are numerous, bilat eral, and small (F ig. 18- 34). How ev er, t hey may be solit ary or t here may be only a f ew . Longit udinal st udies hav e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2707

18 - The Kidney and Ureter also show n t hat t here is a propensit y f or AMLs in T S t o grow and t o hemorrhage, requiring angioembolizat ion or surgery (69,526). T he diagnosis of AML c an be made if CT or MRI doc ument s t he presenc e of mac rosc opic f at (high T 1, low T 2 signal on MRI). Dec reased signal on f at - sat urat ed MRI

sequenc es c an help c onf irm t he diagnosis if only small areas of f at are v isible. Sonographic hy perec hogenic it y is not adequat e, bec ause small RCCs may also be hy perec hoic (154). F luid at t enuat ion f rom hemorrhage may c omplic at e t he appearanc e. As AMLs inc rease in size, t he risk of spont aneous hemorrhage inc reases, and t herapy is rec ommended f or lesions larger t han 4 c m (376). All lesions great er t han 10 c m should be ev aluat ed f or embolizat ion, ev en if t hey are asy mpt omat ic (188). F or t hese large AMLs, selec t iv e art erial embolizat ion may reduc e t he size of AMLs and t heir risk of bleeding (188,353). T he least c ommon renal manif est at ion of T S is ly mphangioleiomy omat osis. T he proc ess, most c ommonly seen in t he c hest , apparent ly result s f rom smoot h musc le prolif erat ion t hat obst ruc t s ly mphat ic c hannels, result ing in dev elopment of c y st ic lesions. F luid- at t enuat ion masses may be seen in t he perinephric spac e in suc h c ases (237).

Von Hippel-Lindau Disease Anot her aut osomal dominant heredit ary disorder t hat may af f ec t t he kidney is v on Hippel- Lindau (VHL) disease (84).

F igure 18- 34 T uberous Sc lerosis (T S). Unenhanc ed (A) and c ont rast ed (B) CT of t he lef t kidney show s mult iple round c ort ic al lesions w it h f at at t enuat ion v alues (ar r ow s). T he f at densit y of t he lesions is c onsist ent w it h angiomy olipomas, a c ommon f inding in T S.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2708

18 - The Kidney and Ureter P.1256 T he c ausat iv e def ec t has been loc alized t o t he short arm of c hromosome 3 (86,290,296). Sev eral phenot y pes exist . T he most c ommon inc ludes present at ion w it h ret inal and CNS hemangioblast omas, renal c y st s and

c anc ers, and panc reat ic c y st s but not w it h pheoc hromoc y t oma. T he next most c ommon pat t ern inc ludes hemangioblast omas, pheoc hromoc y t oma, and islet c ell t umors of t he panc reas but not panc reat ic or renal c y st s or renal c anc ers. In t he least c ommon f orm, hemangioblast omas, pheoc hromoc y t oma, and renal and panc reat ic disease are f ound (86).

F igure 18- 35 Von Hippel- Lindau (VHL). Mult iple renal c y st s present on c ont rast ed CT are t he most c ommon renal lesions in t his sy ndrome. T he presenc e of panc reat ic c y st s (ar r ow s) is also c ommon in VHL.

Renal c y st s are f ound in 60% of pat ient s; t hey are usually bilat eral and may mimic ADPCKD, espec ially bec ause panc reat ic c y st s may be seen (F ig. 18- 35) (290). Of renal masses in VHL pat ient s, 74% are c y st ic (87). Alt hough it is unc ommon f or a c y st t o degenerat e int o a t umor (87), many of t he RCCs in VHL are part ly c y st ic (F ig. 18- 36). T he present at ion of RCC is in muc h y ounger pat ient s in t he set t ing of VHL t han in t he general populat ion (210), and as many as 10% of pat ient s w it h bilat eral RCC are assoc iat ed w it h VHL (238). RCC in pat ient s w it h VHL has a slow er grow t h rat e and higher surv iv al t han pat ient s w it h sporadic RCC (365). St ill, RCC c an be expec t ed t o dev elop in up t o 45% of pat ient s, and, hist oric ally , one t hird of t he deat hs hav e been c aused by RCC (86).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2709

18 - The Kidney and Ureter

F igure 18- 36 Von Hippel- Lindau. On c ont rast ed CT , t he presenc e of mult iple enhanc ing renal masses (ar r ow s) is highly suspic ious f or mult if oc al RCC in t his set t ing.

P.1257 Angiography has been show n t o hav e a sensit iv it y of only 35% f or diagnosing RCC in VHL (342). Bec ause t he RCCs in t hese pat ient s are c ommonly small w hen init ially det ec t ed, CT is probably pref erable t o MRI, but no c omparat iv e st udy has y et been report ed. Small t umors may be missed on init ial CT , but w it h c aref ul f ollow - up, enlarging lesions should be det ec t ed. In a pat ient w it h prev ious renal nephron- sparing surgeries or solit ary kidney , MRI T 1- w eight ed images may ev aluat e f or lesional enhanc ement w it hout t he nephrot oxic it y t hat is of t en assoc iat ed w it h CT c ont rast agent s. T 2- w eight ed MRI is more sensit iv e t han CT f or det ec t ion of t he renal mass pseudoc apsule (500). T his is best demonst rat ed as a t hin low - T 2- signal rim around t he renal mass (500). Remov al of lesions t hat reac h 3 c m in diamet er is rec ommended, w it h an at t empt at renal- c onserv ing surgery rat her t han radic al nephrec t omy , bec ause it is likely RCC w ill ev ent ually dev elop in t he c ont ralat eral kidney (86). F or small t umors, enuc leat ion, part ial nephrec t omy , and perc ut aneous ablat ion are possible t herapies (459,539). A large series of VHL pat ient s show ed no c ases of met ast at ic disease dev elopment w hen 3 c m w as selec t ed as t he t hreshold f or surgery . F urt hermore, loc al resec t ion w as more of t en possible below t his size, and f ew er pat ient s required dialy sis or t ransplant at ion (128). On t he ot her hand, t umors larger t han 3 c m dev eloped met ast ases in 27% of pat ient s (128). If a new mass is det ec t ed on f ollow - up af t er prev ious normal st udies, it is similarly f ollow ed unt il 3 c m large; t hen nephron- sparing surgery is

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2710

18 - The Kidney and Ureter perf ormed bec ause of t he high likelihood of dev elopment of anot her RCC (86,204).

Other Cystic Diseases Mult iloc ular c y st ic nephroma is a loc alized c y st ic disease of t he kidney believ ed by many t o represent a benign neoplasm (20,194,312,385). It is unc ommon and of unknow n et iology and has no heredit ary pat t ern. It is seen most of t en in t w o groups: y oung boy s (3 mont hs t o 4 y ears of age) and adult w omen (ov er 30 y ears of age) (194,385). T he pat hologic c harac t erist ic s are: (a) it is unilat eral and solit ary , (b) it c onsist s of mult iple nonc ommunic at ing epit helial- lined c y st s separat ed by f ibrous sept a t hat c ont ain no renal parenc hy ma, (c ) a w ell- def ined c apsule is c ommon, (d) t he uninv olv ed kidney t issue is normal, and (e) t he c y st s do not c ommunic at e w it h t he c ollec t ing sy st em, but , not unc ommonly , a port ion of t he mass may herniat e int o t he renal pelv is. T he usual mult iloc ular c y st ic nephroma has no malignant pot ent ial and is of t en an inc ident al f inding, but it may c ause sy mpt oms w hen large. On CT , a mult iloc ulat ed c y st ic mass ranging f rom a f ew c ent imet ers t o ov er 10 c m is show n. T he c y st s hav e w at er- at t enuat ion v alue or slight ly higher. T he sept a are usually t hin w it h no enhanc ement (111) (F ig. 18- 37). Usually t he lesion has a t hic k c apsule (5). Sept al c alc if ic at ion is seen in about 10% of c ases, and of t en it is c urv ilinear (312). High at t enuat ion or ot her signs of hemorrhage are rarely seen in mult iloc ular c y st ic nephroma. In general, t hese lesions are in t he Bosniak t y pe 3 c at egory , and t hey c an be dif f ic ult t o disc riminat e f rom c y st ic renal c arc inoma (143,194,195,196,385,386,425,553). On MRI, t he c y st s hav e low T 1, high T 2 signal int ensit y . T he c apsule is hy point ense on T 1 and T 2 sequenc es. Int rav enous gadolinium may demonst rat e enhanc ement of t he c apsule (5). If CT or MRI show s t hic k or nodular enhanc ing sept a, t he mass must be c onsidered renal c arc inoma unt il prov ed ot herw ise, usually by resec t ion. If t here are no enhanc ing c omponent s, benign mult iloc ulat ed c y st is likely , and t he lesion may be f ollow ed if it is not so large as t o c ause sy mpt oms (111).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2711

18 - The Kidney and Ureter

F igure 18- 37 Mult iloc ular c y st ic nephroma. Exc ret ory phase CT of t he lef t kidney demonst rat es a large c y st ic mass w it h mult iple t hin sept at ions. No solid or enhanc ing c omponent w as present .

Mult ic y st ic dy splast ic kidney is usually enc ount ered in neonat es or inf ant s, eit her as a f inding on prenat al sonogram or as a palpable mass af t er birt h. T hese c an persist int o adult lif e, but t hey are small masses in adult s bec ause t hey do not grow f rom c hildhood, and t hey of t en regress c omplet ely (488,533). T he CT appearanc e is c harac t erist ic : a small- t o moderat e- sized c y st ic mass w it h peripheral c alc if ic at ion, oc c upy ing t he expec t ed loc at ion of a kidney (F ig. 18- 38) (501). T he lesion may be uni- or mult iloc ulat ed, and no c ont rast exc ret ion oc c urs. T he c ont ralat eral kidney of t en is hy pert rophied, and may hav e uret eropelv ic junc t ion disproport ion or part ial obst ruc t ion. Loc alized c y st ic disease, also know n as segment al c y st ic disease, is a benign c y st ic c ondit ion t hat af f ec t s all or part P.1258 of one kidney (see F ig. 18- 22). It is not assoc iat ed w it h PCKD or renal f ailure. On CT , a c lust er of nonenhanc ing c y st s w it hout a c apsule oc c urs in only one kidney . Calc if ic at ions may be present in c y st sept at ions. Hy perdense c y st s are unc ommon. F indings are limit ed t o one kidney , and t he c ont ralat eral kidney is normal. On MRI, t he f indings are similar t o t hose seen w it h CT (469).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2712

18 - The Kidney and Ureter

F igure 18- 38 Mult ic y st ic dy splast ic kidney . An at rophic lef t kidney (ar r ow ) is v isible w it h limit ed enhanc ement on c ont rast ed CT .

RENAL MALIGNANCY T he most c ommon sy mpt oms and signs of renal malignanc y are hemat uria, w eight loss, and f lank pain. T omography f indings of t ransit ional c ell c arc inoma inc lude a small isodense f illing def ec t w it hin t he c ollec t ing sy st em. T he lesion may be slight ly hy perdense t o t he surrounding t issues on prec ont rast images. T he t umor is muc h less dense t han c ommonly is seen w it h st ones. T here is v ery lit t le enhanc ement of t he t umor af t er int rav enous c ont rast . How ev er, t his small amount of c ont rast enhanc ement may help dif f erent iat e a t ransit ional c ell c arc inoma f rom c lot or hy podense c alc ulus. T hin CT slic es are required f or ev aluat ion. Rec ent dev elopment of CT urography has allow ed generat ion of images t hat are equiv alent t o int rav enous urography f or demonst rat ion of t he c ollec t ing sy st em and uret er. CT urography uses t hin c oronal slic es w it h mult iplanar rec onst ruc t ion of images t o f orm int rav enous py elogram- like images. T he t ec hnique inv olv es t hin slic es w it h ov erlap of t he slic es f or rec onst ruc t ion. Cont rast is giv en, and st andard CT images are obt ained during art erial or port al phase. F or det ec t ion of a renal mass, nephrographic phase images are superior t o c ort ic omedullary phase images (91). How ev er, t hin- slic e CT images are repeat ed approximat ely 5 t o 10 minut es af t er c ont rast injec t ion (64,335). T hese images are rec onst ruc t ed t o show t he pic t ures t hat resemble int rav enous urography .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2713

18 - The Kidney and Ureter Renal Cell Carcinoma Renal c ell c arc inoma, pat hologic ally adenoc arc inoma, is t he most c ommon primary renal malignanc y in adult s and oc c urs more c ommonly in males. Alt hough most RCCs are sporadic , some may be assoc iat ed w it h sy ndromes suc h as Von Hippel- Lindau. Renal c ell c arc inoma is assoc iat ed w it h t obac c o smoking (117). Ot her risk f ac t ors inc lude exposure t o pet roleum produc t s or asbest os (317). RCC is most c ommonly an inc ident ally disc ov ered solid renal mass (438), but it may present w it h sy mpt oms suc h as pain, hemat uria, w eight loss, or abdominal dist ension. CT is v ery sensit iv e f or f oc al lesions and is t he most sensit iv e t ec hnique f or

c harac t erizing renal enhanc ement . T he t y pic al amount of enhanc ement t hat is needed on CT is 10 HU, using single- slic e sc anner. How ev er, w it h mult idet ec t or or mult islic e CT , more pseudoenhanc ement must be c onsidered. T heref ore, in t hese sit uat ions a t hreshold of 15 t o 20 HU may be bet t er f or small renal masses (314). Lesions t hat do not enhanc e are t y pic ally c onsidered benign, but t he c omplexit y of t he lesion dic t at es f urt her f ollow - up. In t he c ases of enhanc ing renal mass, t he lesion is usually surgic ally resec t ed if t here is a high suspic ion f or malignanc y . If t he lesion is inc ident ally disc ov ered, f ollow - up may be usef ul t o doc ument t he benign or malignant nat ure of t he lesion. Many radiologist s pref er t o hav e t he f ollow - up in 3 t o 6 mont hs t o allow adequat e t ime f or lesion grow t h. T he imaging appearanc e of renal c ell c arc inoma usually inv olv es a f oc al renal mass c ent ered in t he renal c ort ex. T he mass dist ort s t he margins (F ig. 18- 39) of t he kidney in up t o 94% of c ases, regardless of t umor size (566). T he prev alenc e of c alc if ic at ions in a renal c ell c arc inoma is approximat ely 25% (566). Larger renal masses t end t o hav e more c alc if ic at ions t han small renal lesions. CT is muc h more sensit iv e f or c alc if ic at ions t han are c onv ent ional radiographs, ult rasound, or MRI. On CT , t he c alc if ic at ions of RCC may be punc t at e, amorphous, linear, or peripheral (260). P.1259 T here of t en is renal v ein inv asion, and t he t hrombus may ext end int o t he inf erior v ena c av a. T he t hrombus of t en is v asc ular and may show art erial enhanc ement (F ig. 18- 40).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2714

18 - The Kidney and Ureter

F igure 18- 39 Small renal c ell c arc inoma. On c ort ic omedullary phase CT , a small enhanc ing c ort ic al mass is present . Ev en a small lesion suc h as t his w ill usually disrupt t he c ort ic al margin (ar r ow ).

F igure 18- 40 Large RCC w it h enhanc ing t umor t hrombus. T w o images of c ont rast ed CT (A, B) show a large het erogenous lef t renal mass w it h ext ension of t umor int o t he lef t renal v ein (arrow s) and IVC. On t he slight ly more c ranial image, t he IVC (c ur v ed ar r ow ) is expanded w it h enhanc ing t umor t hrombus. Not e is made of a sy nc hronous enhanc ing lesion in t he right kidney (ar r ow heads).

Renal c ell c arc inoma does not usually met ast asize w hen less t han 3 c m diamet er, but exc ept ional c ases do oc c ur (105). RCC of t en met ast asizes t o t he liv er, bone, lungs, and nodes. One st udy suggest s t hat more t han t w o t hirds of pat ient s w it h st age IV disease hav e lung met ast ases (50). Liv er met ast ases are of t en hy perv asc ular (F ig. 18- 41), and a met ast asis may be v isible only on art erial phase CT . T he lesions, if small, are of t en inv isible on

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2715

18 - The Kidney and Ureter

port al phase imaging. When v isualized on CT , t he lesions on art erial phase are of t en bright . T here may be a small peripheral rim, know n as a pseudoc apsule (392).

F igure 18- 41 Hy perenhanc ing hepat ic met ast ases. Numerous bright ly enhanc ing liv er lesions, c onsist ent w it h met ast ases, are present on art erial phase CT in pat ient w it h know n renal c ell c arc inoma. RCC met ast ases are c ommonly hy perv asc ular.

Inc ident al renal lesions hav e a signif ic ant ly low er likelihood of malignant pot ent ial and met ast at ic disease, as c ompared w it h lesions t hat present w it h sy mpt oms. A great er perc ent age of inc ident al lesions are c y st ic t han seen in sy mpt omat ic RCCs (33). Less t han 15% of RCCs hav e c y st ic c hanges (195). Simple hy podense lesions are c onsidered simple c y st s, and do not need f ollow up. How ev er, if t here is any c omplexit y of t he lesion, suc h as c alc if ic at ions, sept at ions, or a c ent ral loc at ion of t he lesion, f ollow - up by CT is of t en rec ommended. Cy st ic RCC is usually asy mpt omat ic and det ec t ed inc ident ally (96). When nec rot ic RCC is exc luded and c y st ic lesions w it h less t han 25% of t he lesion appearing solid is c onsidered, t he malignant pot ent ial of t hese mult iloc ular c y st ic RCCs is v ery low (361). If t hic k sept at ions, enhanc ement , c alc if ic at ions, or a signif ic ant amount of c omplexit y w it h a solid c omponent is present w it hin a c y st ic lesion, t he risk of malignanc y is great er (195). Obv iously , t he presenc e of met ast at ic disease or v enous inv asion suggest s malignant pot ent ial. In c y st ic RCC, MRI may also be more sensit iv e t han CT f or enhanc ement (361). MRI is anot her modalit y f or t he c harac t erizat ion of a f oc al renal mass. RCC is t y pic ally mildly hy point ense t o t he renal c ort ex on T 1- w eight ed imaging (F ig. 18- 42). On T 2- w eight ed images, t he lesion is mildly high T 2 signal int ensit y

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2716

18 - The Kidney and Ureter (225) MRI is v ery sensit iv e t o enhanc ement bec ause of gadolinium c ont rast , and most renal c arc inomas w ill show enhanc ement (see F ig. 18- 42C). How ev er, MRI is unable t o prov ide exac t enhanc ement measurement s, unlike CT Hounsf ield unit s. T he enhanc ement of renal t umors on MRI is measured w it hout unit s. Based on T 1- w eight ed images, a 15% t o 20% enhanc ement is c onsidered diagnost ic . Enhanc ement of sept at ions or solid c omponent is also c onsist ent w it h neoplasm. How ev er, as in CT , renal adenoma may also enhanc e. Most RCCs hav e a hy point ense pseudoc apsule at t he periphery of t he t umor (559). P.1260 F at - sat urat ed images are rec ommended bec ause gross f at may be det ec t ed w it h an angiomy olipoma. T heref ore, if t here is a signal dropout on f at sat urat ed images, t he diagnosis of angiomy olipoma c an be made. It is ext remely rare f or renal c ell c arc inoma t o c ont ain mic rosc opic f at . MRI is less sensit iv e t han CT f or det ec t ion of c alc if ic at ions.

Staging of Renal Cell Carcinoma St aging of renal c ell c arc inoma is a c rit ic al part of t he ev aluat ion of a pat ient w it h renal mass. T he st aging af f ec t s t he surv iv al of t he pat ient (515) and of t en t he t herapeut ic approac h. T he main c lassif ic at ions sc hemes are Robson's c lassif ic at ion (422) and T NM c lassif ic at ion sc heme (7). T he st aging depends on t he lesion size, ext ension bey ond t he kidney margins, and inv asion of t he perinephric f at . Inv olv ement bey ond Gerot a's f asc ia is a negat iv e c linic al indic at or. Loc al spread t o regional nodes or v asc ular inv asion are c lassif ic at ion f ac t ors. Prev ious st udies hav e show n t hat CT is v ery ac c urat e in t he st aging of RCC (419). A rec ent st udy of 3D MRI show ed v ery high (97%) ac c urac y f or st aging of renal masses. In t his st udy t here w as 100% sensit iv it y f or c ollec t ing sy st em inv asion (227). How ev er, anot her rec ent st udy of c ombined st aging of RCC by CT and MRI w as only 67% ac c urat e (538).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2717

18 - The Kidney and Ureter

F igure 18- 42 RCC on MRI. A small c ort ic al lesion in t he lef t kidney has high T 2 signal (A), and mildly low T 1 signal int ensit y (B). On T 1- w eight ed image af t er int rav enous gadolinium (C ), t here is bright enhanc ement of t he lesion w it h small c ent ral sc ar or nec rosis. Not e t hat t he appearanc e is v ery similar t o an onc oc y t oma.

It has been not ed t hat t he st age of inc ident ally disc ov ered RCCs is generally low er t han t hat in sy mpt omat ic pat ient s. F urt hermore, st age- f or- st age surv iv al is higher in pat ient s w it h inc ident al RCCs (270) Most inc ident al enhanc ing renal masses are renal c ell c arc inomas, but approximat ely 82% are st age I lesions as opposed t o 37% st age I t umors in suspec t ed c ases (379). St age I and II RCCs are limit ed by t he renal c apsule and Gerot a's f asc ia, respec t iv ely (422). By T NM c lassif ic at ion, st age T 1a t umors are less t han 4 c m, st age T 1b measure 4 t o 7 c m, and st age II t umors are larger t han 7 c m (7). T hese t umors may be t reat ed w it h loc al resec t ion f or c ure. Surgery may inv olv e radic al nephrec t omy f or large t umors or masses in t he midport ion or c ollec t ing sy st em regions. How ev er, t he use of part ial nephrec t omy has inc reased in rec ent y ears w it h c omplic at ion rat es similar t o t hose of radic al nephrec t omy (97). If a t umor inv olv es t he pole of a kidney , t hen a part ial

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2718

18 - The Kidney and Ureter nephrec t omy may be possible. Small t umors may be resec t ed or enuc leat ed laparosc opic ally , but higher c omplic at ion P.1261

rat es hav e been report ed (412). T he size of t he mass as w ell as t he presenc e of adenopat hy inf luenc es t he c hoic e of resec t ion t ec hnique. F or small isolat ed t umors, t he c anc er- spec if ic 5- y ear surv iv al rat e is 89% af t er nephron- sparing surgery c ompared w it h a 91% 5- y ear surv iv al rat e af t er radic al nephrec t omy (133,183,289). T heref ore, in t hese c ases, nephron- sparing surgery is pref erable. Radiof requenc y ablat ion is a saf e and ef f ec t iv e t herapy f or loc alized t umors, espec ially w hen t hey are smaller t han 3 c m and exophy t ic . In t umors bet w een 3 and 5 c m, as many as 44% may require a sec ond ablat ion proc edure (162). F or st ages I and II lesions, CT may hav e limit at ions in disc erning w het her t here is ext ension bey ond Gerot a's c apsule (243). T hic kening of st ruc t ures in t he perinephric spac e may suggest st age III disease, but t he f inding is not spec if ic bec ause it may result f rom edema or hy peremia (271). Alt hough CT is limit ed in it s abilit y t o det ec t loc al ext ension int o t he c apsule, t his f inding does not signif ic ant ly af f ec t management and out c ome bec ause bot h st ages are resec t able w it h good prognosis. MRI is similar t o CT in it s limit ed ac c urac y f or assessing ext ension of t umor t hrough Gerot a's f asc ia (142,359), but again, t his dist inc t ion does not af f ec t t reat ment if radic al nephrec t omy is perf ormed. How ev er, t he dif f erent iat ion is more import ant if nephron- sparing surgery is c onsidered. St age III t umor c lassif ic at ion inc ludes inv asion of t he renal v ein, IVC, adrenal inv olv ement , or regional adenopat hy (7,422). In as many as 30% of pat ient s w it h renal c ell c arc inoma, t here is t umor t hrombus in t he renal v ein or IVC (see F ig. 18- 40) t hat w ill need t o be remov ed at t he t ime of surgery (122,177,211,422,496). IVC inv olv ement is rare in small t umors (248). A det erminant of t he c omplexit y of surgery is w het her t he t umor t hrombus ext ends int o t he right at rium. In t his c ase, a c ombined surgery by urology and c ardiot horac ic surgery is of t en nec essary . Met ast at ic adenopat hy in t he ret roperit oneal spac e (F ig. 18- 43) also has poor prognost ic signif ic anc e (327). In t hese c ases, nodal dissec t ion may be perf ormed. CT c an det ec t loc al adenopat hy , and c rit eria hav e generally used a 1- c m t hreshold (489). How ev er, t his c rit erion has been unsuc c essf ul in dif f erent iat ing reac t iv e nodes f rom met ast at ic adenopat hy . A signif ic ant proport ion of nodes w it h minimum diamet er measuring at least 1 c m do not c ont ain malignanc y on pat hologic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2719

18 - The Kidney and Ureter examinat ion (458). F or t his reason, surgery is st ill pursued in pat ient s w it h

isolat ed ret roperit oneal adenopat hy . On t he ot her hand, nodes less t han 1 c m in diamet er may c ont ain mic rosc opic met ast ases. T he presenc e of an adrenal mass should prompt c onc urrent adrenalec t omy at t he t ime of surgery , unless it f it s at t enuat ion c rit eria f or a benign adenoma. Adrenal met ast at ic inv olv ement oc c urs in less t han 10% of RCC pat ient s (166).

F igure 18- 43 RCC nodal met ast asis. A large lef t para- aort ic nodal mass (n) lies adjac ent t o t he lef t renal hilum. T his is a c ommon loc at ion f or nodal met ast ases. Not e t he t hrombus (ar r ow ) in t he IVC.

CT is v ery spec if ic f or renal v ein inv asion by t umor t hrombus w it h 98% spec if ic it y (548). A hy podense f illing def ec t out lined by c ont rast in t he renal v ein on a CT using c ort ic omedullary or nephrographic phase t iming is diagnost ic f or t hrombus (319). Het erogeneous enhanc ement of t he t hrombus on nephrographic phase c an c onf irm t umor t hrombus. T he inf low of unenhanc ed blood f rom t he pelv is may be mist aken f or IVC t hrombus (482), and in c ert ain c ases delay ed images may be needed t o det ermine w het her an IVC def ec t is inf low or t hrombus. T umor t hrombus of t en enlarges t he c aliber of t he IVC, and it may be het erogeneous and inv ade t he IVC w all (see F ig. 1840). T here may be bland t hrombus inf erior t o t umor t hrombus in t he IVC as a result of oc c lusion of t he lumen. In st age III disease, MRI is more sensit iv e f or IVC t hrombosis, and t he diagnosis is aided by mult iplanar abilit y of MRI t o image t he IVC in a c oronal plane. MRI is more sensit iv e f or IVC w all inv asion t o c onf irm t umor t hrombus (357). It has a similar ac c urac y t o CT f or c harac t erizat ion of st age III disease. How ev er, magnet ic resonanc e imaging is more ac c urat e t han CT f or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2720

18 - The Kidney and Ureter t he v enous v asc ular inv asion or t umor t hrombus w it hin t he IVC (222,247,248,410). Gradient ec ho images may det ec t a low signal def ec t w it hin t he high signal lumen of t he IVC (429) or high signal in t he low signal f low v oid (F ig. 18- 44). Cont rast - enhanc ed MRI has t he abilit y t o perf orm

c oronal sourc e images during c ont rast injec t ion t o ev aluat e f or t hrombus as a f illing def ec t . F urt hermore, T 2- w eight ed images in t he axial or c oronal planes may be usef ul t o ev aluat e f or v asc ular inv asion. T he abilit y of MRI t o det ec t nodes is similar t o t hat of CT , but it is similarly limit ed in it s abilit y t o dif f erent iat e reac t iv e and malignant nodes. Based on nodal size c rit eria alone, MRI and CT are similar in sensit iv it y and spec if ic it y f or met ast at ic adenopat hy . More t han 50% of abnormally enlarged nodes (great er t han 1 c m) in t he set t ing of RCC are a result of inf lamed, nonmet ast at ic nodes (489).

F igure 18- 44 RCC w it h c av al inv asion. A: On axial T 1 w eight ed MRI, a high signal int ensit y lesion (arrow ) is present w it hin t he normal f low v oid in t he IVC, c onsist ent w it h t hrombus f ormat ion. B: In anot her pat ient , c ont rast ed c oronal T 1- w eight ed image show s an int ermediat e int ensit y t hrombus expanding t he IVC (c ur v ed ar r ow s) and lef t renal v ein (ar r ow heads).

P.1262 How ev er, rec ent ult rasmall supramagnet ic iron oxide part ic le MRI c ont rast agent s hav e show n promise f or dif f erent iat ing reac t iv e nodes f rom met ast at ic nodes on delay ed MRI imaging, ev en w hen t radit ional diagnost ic c rit eria suc h as size are normal. A normal node w ill t ake up t his agent , and t he part ic les c reat e a drop in T 2* signal. Met ast at ic nodes do not t ake up t he part ic les and demonst rat e no drop in signal (189).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2721

18 - The Kidney and Ureter St age IV c anc er inv olv es dist ant met ast ases or spread t o adjac ent organs

(see F igs. 18- 41 and 18- 45), ot her t han t he adrenal (422). Met ast at ic disease t o dist ant organs c ommonly inv olv es t he lung, liv er, bone, or brain. RCC rarely met ast asizes w hen it is less t han 3 c m in diamet er (105). How ev er, onc e organs are inv aded by t he t umor, t he prognosis is ext remely poor. In st age IV disease, t he t herapy is palliat iv e bec ause a surgic al c ure is not possible. How ev er, an isolat ed met ast asis may be t reat ed w it h loc al resec t ion or perc ut aneous t herapy . Radiof requenc y ablat ion of a solit ary hepat ic met ast asis may prolong surv iv al. CT is v ery ac c urat e in st aging renal masses w it h dist ant met ast ases (243). Direc t inv asion of adjac ent organs, like dist ant met ast ases, is a spec if ic indic at or of poor prognosis. Large t umors may direc t ly inv ade t he adjac ent musc les, liv er, panc reas, c olon, or spleen. Inv asion of adjac ent organs may limit surgic al resec t ion or inc rease t he amount of t ime at surgery . Oc c asionally a renal mass may appear t o inv ade t he liv er or spleen, w hen it ac t ually is only dist ort ing t he margin of t he organ w it hout direc t inv asion (243). Mult iplanar CT rec onst ruc t ions or MRI ac quisit ions may be benef ic ial t o help dif f erent iat e inv asion of t he organ f rom ext ension adjac ent t o t he organ, but t here are no spec if ic signs of minimal inv asion. MRI may underest imat e T 4 st age disease P.1263 by underest imat ing direc t organ inv asion (132). MRI may dif f erent iat e high T 2 signal of t umor f rom t he low T 2 signal of normal st ruc t ures suc h as t he psoas musc le (247).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2722

18 - The Kidney and Ureter

F igure 18- 45 RCC w it h met ast asis t o panc reas. On c ont rast ed CT in a pat ient w it h prior right nephrec t omy (surgic al c lip v isible), a bright ly enhanc ing mass (ar r ow ) is present in t he panc reat ic body . RCC met ast ases are of t en hy perv asc ular.

Treatment and Follow-up Imaging T he t reat ment of RCC depends on t he st aging of t he t umor. F or small RCCs, espec ially t hose t hat are inc ident ally disc ov ered, t he met ast at ic rat e is low w hen lesions measure less t han 3 c m in diamet er. F or minimally c omplex lesions, f ollow - up is usually c hosen unless t here are ot her c onsiderat ions or risk f ac t ors. In pat ient s w ho c hoose surgery f or a Bosniak I or II lesion, post surgic al f ollow - up is based on c linic al risk f ac t ors. F or c y st ic lesions t hat are at least Bosniak III c at egory , surgery is most c ommonly pref erred if c linic ally possible, and c loser post surgic al f ollow - up is w arrant ed bec ause of t he inc reased risk of rec urrenc e. Baseline CT and f ollow - up CT at 6- mont h int erv als f or 2 y ears is generally rec ommended. T he most likely sit es f or rec urrenc e of t umor are in t he nephrec t omy sit e or t he adjac ent st ruc t ures. Solid organ rec urrenc e may also oc c ur in t he liv er, c ont ralat eral kidney , or adrenal.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2723

18 - The Kidney and Ureter Part ial nephrec t omy or nephron sparing surgery is more c ommonly perf ormed f or small lesions and hav e show n a similar t umor rec urrenc e rat e t o nephrec t omy (133,183,289). Low - grade lesions measuring less t han 4 c m are c andidat es f or nephron- sparing surgery (289). Part ial nephrec t omy has

bec ome espec ially usef ul in t he t reat ment of t he inc ident ally disc ov ered renal mass, w hic h are of t en small and of low er st age (517). T his proc edure is of t en perf ormed laparosc opic ally . Part ial nephrec t omy should be espec ially c onsidered in a pat ient w it h abnormal c ont ralat eral kidney . Af t er part ial nephrec t omy , it is import ant t o f ollow all pat ient s w it h RCC t reat ed by nephron- sparing surgery , bec ause t here may be sy nc hronous lesions in t he remaining kidney s (371); how ev er, t he t iming of f ollow - up may v ary based on t he underly ing t umor (374). F or small and exophy t ic lesions, perc ut aneous radiof requenc y ablat ion is a saf e, ef f ec t iv e t herapy (162).

Cystic Lesions and Rare Tumor Types Whereas most renal c ell c arc inomas are solid enhanc ing lesions, some are c y st ic . T he c lassif ic at ion sy st em dev eloped by Bosniak has been used t o st rat if y c y st ic renal lesions int o risk of malignanc y (47). A simple c y st is c lassif ied as a Bosniak t y pe I lesion (see F igs. 18- 21, 18- 22, and 18- 23), w it h no signif ic ant risk of malignanc y . T his appearanc e inc ludes an imperc ept ible w all, w it hout sept at ions, c alc if ic at ions, or enhanc ement . T he lesion should inc lude at least 25% of t he margin of t he kidney so t hat t he w all c an be ev aluat ed. A t y pe II c y st (see F ig. 18- 25A) has c harac t erist ic s t hat are minimally w orrisome but do not f it st ric t c rit eria f or a simple c y st . T hin sept at ions, c alc if ic at ions, or a c ent ral loc at ion f ulf ills a Bosniak II c rit erion. Hy perdense c y st s t hat do not demonst rat e enhanc ement also f it int o t his c at egory . T he risk of malignanc y in t hese pat ient s is usually less t han 14% (103). A Bosniak t y pe III c y st (see F ig. 18- 25B) has more w orrisome f eat ures t han a Bosniak II c y st . T hese c harac t erist ic s may inc lude t hic ker c alc if ic at ions or t hic ker sept at ions. A small amount of enhanc ement may be v isualized in t he periphery of t he lesion (47). Wit h t he exc ept ion of a single small series of f our c ases w it h a high rat e, Bosniak III lesions hav e a 25% t o 59% likelihood of malignanc y (103). A Bosniak IV c y st (F ig. 18- 46) has c harac t erist ic s c onsist ent w it h c y st ic renal malignanc y . T his inc ludes enhanc ement of t he lesion. T hic k sept at ions and c alc if ic at ions are of t en present . Usually t here is more t han one w orrisome f inding of malignanc y in t hese c y st s. T he likelihood of renal c ell c arc inoma in t hese pat ient s is approximat ely 95%. If c linic ally

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2724

18 - The Kidney and Ureter possible, surgery is rec ommended in Bosniak III or Bosniak IV c y st . T here has been f ollow - up of Bosniak III c y st s in pat ient s w ho w ere higher risk f or

surgery . T he Bosniak c lassif ic at ion sy st em w as dev eloped f or CT ev aluat ion of c y st ic renal lesions. T he c rit eria do not exac t ly hold f or ult rasound or MRI imaging. Bec ause of t he inc reased abilit y of ult rasound t o det ec t sept at ions, it is possible t hat ult rasound w ould ov erest imat e t he risk of malignanc y based on sept at ions. How ev er, CT is more sensit iv e f or c alc if ic at ions. MRI is more sensit iv e f or c ont rast enhanc ement but less sensit iv e f or c alc if ic at ions. T he c harac t erist ic s of a simple c y st on MRI are a homogeneous, bright T 2- w eight ed signal w it hout v isible sept at ions or w all t hic kening. Af t er int rav enous P.1264 gadolinium c ont rast , t here is no enhanc ement of t he lesion on T 1- w eight ed images (320). T he presenc e of high T 1- w eight ed signal on prec ont rast images is usef ul t o help det ec t heme produc t s. T his helps improv e t he diagnosis of hemorrhagic renal c y st in t he absenc e of int rav enous c ont rast enhanc ement .

F igure 18- 46 Bosniak IV c y st ic renal c arc inoma. On c ont rast ed CT , c y st ic lef t renal mass has t hic kened w all and a f oc al enhanc ing nodule (ar r ow ) w it hin t he c y st w all. T his f inding suggest s a high likelihood of malignanc y , nec essit at ing surgic al management .

Subsequent t o t he init ial researc h by Bosniak, a modif ic at ion of t he c lassif ic at ion sy st em w as made. A Bosniak II F c at egory w as c reat ed. Lesions

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2725

18 - The Kidney and Ureter

in t his c at egory hav e Bosniak II c harac t erist ic s, but t hey hav e more w orrisome f eat ures suc h t hat a f ollow - up st udy is rec ommended t o c onf irm st abilit y of size. St abilit y of size ov er a 2- y ear period is c onsidered nec essary t o doc ument st abilit y . How ev er, ev en slow - grow ing renal malignanc ies may hav e minimal c hange ov er 2 y ears. T he presenc e of t w o simple c y st s adjac ent t o one anot her is a pot ent ial pit f all of t he Bosniak c lassif ic at ion sy st em. In t hese c ases, t he t w o c y st s may resemble a single c y st w it h a sept at ion. How ev er, if t here are no ot her w orrisome f indings, t he appearanc e is c onsist ent w it h a v ery low likelihood of malignanc y . Ac quired c y st ic renal disease (see F ig. 18- 31) is a risk f ac t or f or RCC. Ac quired c y st ic disease dev elops af t er approximat ely 3 t o 10 y ears of hemodialy sis (323). T here is inc reased inc idenc e of RCC in t hese pat ient s (323). T he det ec t ion of RCC in t hese pat ient s is best on early phase at approximat ely 40 sec onds af t er injec t ion of c ont rast , bec ause of t he relat iv e pauc it y of normal c ort ic al enhanc ement relat iv e t o t umors. F urt hermore, t his t iming allow s det ec t ion of papillary RCC, t he most c ommon RCC t y pe in ac quired c y st ic disease, w hic h has less enhanc ement during lat er phases (503). Chromophobe RCC is a rec ent ly c lassif ied subt y pe of RCC. It oc c urs in males or f emales (358). T he t umor is t y pic ally large at present at ion and homogenous in appearanc e w it hout nec rosis or hemorrhage. T he mass is generally hy pov asc ular on c ont rast - enhanc ed CT relat iv e t o c lear c ell RCC (358).

Transitional Cell Carcinoma Urot helial t umors are less c ommon in t he upper urinary t rac t t han renal c ell c arc inoma (283). How ev er, t ransit ional c ell c arc inoma (T CC) is t he sec ond most c ommon renal neoplasm in adult s and represent s t he v ast majorit y of urot helial t umors. It is most c ommon in t he urinary bladder, f ollow ed in f requenc y by t he uret er and renal pelv is. Only approximat ely 10% of urot helial t umors are of ot her et iologies (160). T he next most c ommon et iology is squamous c ell c arc inoma, assoc iat ed w it h inf lammat ion, nephrolit hiasis, and leukoplakia (35,206,363). Squamous c ell c arc inoma is aggressiv e and may present as an inf ilt rat ing mass, a t hic kening of t he renal pelv ic w all, or as a f illing def ec t in t he c ollec t ing sy st em (360). Adenoc arc inomas represent less t han 1% of urot helial malignanc ies (160), and t hey are assoc iat ed w it h uret erit is glandularis and c hronic inf lammat ion (268).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2726

18 - The Kidney and Ureter Risk f ac t ors f or T CC inc lude nonst erioidal ant i- inf lammat ory drug (NSAID) abuse, t obac c o use, and some oc c upat ional exposures (11). T CC is more c ommon in males (328). T he inc idenc e of T CC may be inc reased in horseshoe kidney (355). Pat ient s w it h T CC most c ommonly present w it h hemat uria (407) or, less c ommonly , w it h pain or w eight loss. Init ial det ec t ion of an urot helial lesion in a sy mpt omat ic pat ient has been most of t en made by int rav enous urography . T he f indings on IVU inc lude a f illing def ec t out lined by exc ret ed c ont rast . T here may be obst ruc t ion of t he kidney w it h non- opac if ic at ion of t he c ollec t ing sy st em or uret er. T he c ollec t ing sy st em may be dist ort ed by mass. In small t umors, only a small poly poid def ec t may be v isible.

Oc c asionally , sonography may det ec t a c ollec t ing sy st em lesion in t he c aly c es or renal pelv is. Prior t o CT urography and MR urography t ec hniques, init ial det ec t ion of c ollec t ing sy st em lesions w as limit ed in c ross- sec t ional imaging. F or CT or MRI ev aluat ion, it is import ant t o inc lude images in t he exc ret ory phase (3 t o 5 minut es af t er injec t ion) t o show low - at t enuat ion mass margins inv olv ing t he c ollec t ing sy st em or uret er, as out lined by c onc ent rat ed dense c ont rast . T here are t hree general CT imaging appearanc es of a small t ransit ional c ell c arc inoma. On CT , t he most c ommon appearanc e of T CC is a small, hy podense lesion in t he renal c ollec t ing sy st em (F ig. 18- 47) (534). T he lesion w ill hav e sof t t issue at t enuat ion (less t han 40 HU) t hat is less at t enuat ing t han is c ommon f or urinary c alc uli, exc luding indiniv ir st ones. T he at t enuat ion of T CC is also slight ly low er t han a blood c lot w it hin t he c ollec t ing sy st em but higher t han t he at t enuat ion of urine (160). T CC w ill enhanc e 10 t o 50 HU af t er int rav enous c ont rast (160,364,384). T he amount of enhanc ement is less t han P.1265 t he surrounding renal parenc hy ma, and t heref ore t he lesion appears hy podense relat iv e t o t he kidney (21). St ill, t his mild enhanc ement of T CC dif f erent iat es t his c ause f rom ot her nont umorous diagnoses, suc h as st one or c lot . In t he kidney , T CC is usually more c ent ral t han RCC ow ing t o it s origin in t he urot helium. T ransit ional c ell c arc inomas may c ont ain st ippled c alc if ic at ion (124) (F ig. 18- 48). Nec rosis w it hin a larger mass is not unc ommon (53). T CC is bilat eral in less t han 2% of pat ient s (218). Unlike renal c ell c arc inoma, a t ransit ional c ell c arc inoma does not c ommonly inv olv e t he renal v ein, alt hough ev en c ases inv olv ing t he inf erior v ena c av a hav e been report ed (288). Renal pelv is t ransit ional c ell c arc inoma does oc c asionally arise w it hin t he proximal uret er (F ig. 18- 49).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2727

18 - The Kidney and Ureter

F igure 18- 47 T CC f illing def ec t in renal pelv is. On nephrographic phase CT , a hy podense f illing def ec t expands t he lef t renal pelv is (ar r ow s).

F igure 18- 48 Renal pelv is T CC w it h st ippled c alc if ic at ion. A: On prec ont rast image, a f oc al sof t t issue densit y lesion f ills t he right renal pelv is. T he mass has mult iple st ippled c alc if ic at ions (ar r ow heads), w hic h are t he most c ommon appearanc e of c alc if ic at ions in T CC. B: Af t er int rav enous c ont rast , mild enhanc ement (ar r ow ) of t he mass is present .

T CC may present as a loc ally aggressiv e inf ilt rat iv e renal mass (F ig. 18- 50) (193). T he t umor may be large and nec rot ic (53). T he margins of t he mass may be ill def ined. Inv olv ement of t he renal parenc hy ma c an be det ec t ed by f inding a hy poenhanc ing mass inv olv ing t he parenc hy ma or a het erogeneous abnormal hy poenhanc ement disrupt ing t he normal enhanc ing parenc hy ma on nephrographic phase (523). T he mass originat es f rom t he c ent ral region of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2728

18 - The Kidney and Ureter kidney and expands t he kidney sy mmet ric ally (21,53,283). T he renal c ont ours are usually not disrupt ed, unlike in RCC, but t his may rarely oc c ur w it h T CC (53) (F ig. 18- 51).

F igure 18- 49 T CC in proximal uret er w it h obst ruc t ion. A: Cont rast enhanc ed CT at t he lev el of t he renal hilum show s moderat e hy dronephrosis. B: Image of t he proximal uret er on same series has a f oc al mass (ar r ow ) c ausing t he obst ruc t ion, c onsist ent w it h T CC.

A t hird appearanc e of T CC is t hic kening of t he c ollec t ing sy st em urot helium or uret eral w all (21) (F ig. 18- 52).

F igure 18- 50 Inf ilt rat iv e T CC. Cont rast enhanc ed CT show s a poorly marginat ed c ent ral renal mass (* ) inv ading t he renal hilum. Hilar adenopat hy is also present (arrow ).

P.1266

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2729

18 - The Kidney and Ureter

T he t hic kening may be sy mmet ric or ec c ent ric , and t here may be expansion of t he c ollec t ing sy st em abov e t he area of t hic kening (160,375). In some c ases, t he mass may ext end f rom t he c ollec t ing sy st em int o t he uret er. T here may be t hic kening of t he uret er w all. T he t hic kening usually inv olv es a f oc al port ion of t he uret er and may c ause obst ruc t ion. In ac ut e urinary obst ruc t ion, t here may be delay ed upt ake and exc ret ion of c ont rast by t he kidney . F or upper t rac t t ransit ional c ell c arc inoma, t he likelihood of dev elopment of anot her T CC in t he kidney s, uret ers, or urinary bladder is 40% (242). How ev er, af t er radic al c y st ec t omy f or urinary bladder t ransit ional c ell c arc inoma, t he likelihood of upper t rac k met ast ases is only 2% (497).

F igure 18- 51 T CC expanding kidney . Inf ilt rat iv e t umor dif f usely expands t he kidney w it h minimal disrupt ion of t he c ort ic al margin. T his mass exhibit s areas of nec rosis (ar r ow ) and massiv e ret roperit oneal adenopat hy (n).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2730

18 - The Kidney and Ureter

F igure 18- 52 T CC t hic kening of t he uret er. Cont rast ed CT show s c onc ent ric t hic kening (ar r ow ) of t he right uret er w it h periuret eral st randing.

St aging of t ransit ional c ell c arc inomas of t he upper urinary t rac t has dif f erent prognost ic indic at ors t han renal c ell. Ov erall ac c urac y of CT st aging f or upper t rac t T CC is 43% t o 60% (60,396,445). Carc inoma in sit u and t umors limit ed t o t he submuc osa hav e t he best prognosis. T umors inv ading bey ond t he subepit helial t issue (st age II) and musc ularis (st age III) hav e w orsened prognost ic out c omes, and det erminat ion of musc le inv asion is import ant in t herapeut ic planning (8). Unf ort unat ely , IVU and CT are not ac c urat e f or dif f erent iat ing w het her t here is musc ular inv asion by a small t umor (21,283). Ot her indic at ors of st age III disease are t umor inv asion of t he renal parenc hy ma or peripelv ic /periuret eral f at . CT has show n v ariable ac c urac y in t he det ec t ion of nodal inv olv ement (st age IV). One st udy has show n sensit iv it y and spec if ic it y f or nodal met ast ases as high as 87% and 98%, respec t iv ely . Ot her st udies hav e show n less promising ac c urac y f or c harac t erizat ion of t he presenc e or absenc e of malignant nodal disease (329,445). F or st age I and st age II t umors, surgic al nephrouret erec t omy is generally rec ommended, but some pat ient s may now be amenable t o loc alized surgic al resec t ion (522). Indic at ors of w orse prognosis are inv asion of t he parenc hy ma or periuret eral t issue (st age III) f or w hic h CT has show n mixed result s in det ec t ing (14,523). Anot her f inding c onsist ent w it h st age III disease is sof t t issue inf ilt rat ion of t he peripelv ic f at (523). St age IV disease is c harac t erized by inv asion of adjac ent organs, ly mph node met ast ases, or met ast at ic disease

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2731

18 - The Kidney and Ureter t o ot her organs, suc h as bone or lung (523). Generally , if t here are dist ant met ast ases, surgery is not perf ormed and sy st emic t herapy is used. P.1267 MR appearanc e of a small T CC usually appears as a f oc al lesion inv olv ing t he renal pelv is or c aly c eal sy st em. T he lesion may demonst rat e low signal int ensit y on prec ont rast T 1- w eight ed images. Af t er int rav enous gadolinium c ont rast , t he lesions c an demonst rat e enhanc ement on similar T 1- w eight ed sequenc es. In t he uret ers, bot h MRI and CT hav e show n good sensit iv it y and spec if ic it y f or st aging in a small series (14). F or t he urinary bladder, c ont rast enhanc ement w it h gadolinium agent s may allow dif f erent iat ion of muc ularis muc osal inv asion, w hic h is limit ed on CT (508). T he role and ac c urac y of MR urography is st ill undet ermined f or det ec t ion of upper t rac t urot helial t umors.

F igure 18- 53 Ly mphoma as bilat eral f oc al renal masses. Cont rast enhanc ed CT show homogenous, mildly enhanc ing renal masses in t he right (A) and lef t (B) kidney . T his is t he most c ommon appearanc e of renal inv olv ement by sy st emic ly mphoma.

Lymphoma Renal ly mphoma is usually a part of a sy st emic disease and is assoc iat ed w it h adenopat hy or inv olv ement of ot her organs suc h as t he liv er and gast roint est inal t rac t (418). Sy st emic ly mphoma of t en inv olv es t he kidney s on pat hologic rev iew at aut opsy (426). Renal inv olv ement by ly mphoma is of t en asy mpt omat ic (146). T he det ec t ion of renal inv olv ement usually oc c urs at imaging st udy , suc h as CT or MRI, det ec t ed in less t han 6% of c ases (441). Non- Hodgkin's ly mphoma is muc h more c ommon t han Hodgkin's ly mphoma in renal inv olv ement (418).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2732

18 - The Kidney and Ureter CT is more sensit iv e t han ult rasound in det ec t ion of renal ly mphoma (547). T here are f our c ommon present at ions of renal ly mphoma. T he most c ommon t y pe is inv olv ement of t he kidney s by mult iple f oc al renal lesions oc c urring in approximat ely one t hird of c ases (418) (F ig. 18- 53). F oc al solit ary renal parenc hy mal mass is a c ommon CT appearanc e, but renal ly mphoma is more

of t en mult iple and c ommonly bilat eral (6,418). On CT , f oc al renal masses hav e at t enuat ion similar t o or slight ly dif f erent f rom t he renal parenc hy ma on nonenhanc ed images. Af t er int rav enous c ont rast , t he enhanc ement of t he lesions is less t han t hat of t he surrounding renal parenc hy ma. Small lesions are generally homogeneous. In larger lesions, t here may be nec rosis and het erogeneit y . Calc if ic at ions are rare unless t here has been t herapy . Inv asion of t he kidney by a renal hilum mass is also possible (F ig. 18- 54). Renal ly mphoma does not usually inv olv e t he renal v ein or IVC, alt hough it may rarely oc c ur (537). In c ases of renal inv olv ement , t here is a perinephric inv olv ement of t he ly mphoma in approximat ely one t hird of pat ient s, most of w hic h also hav e parenc hy mal inv olv ement (334,418). A t hird appearanc e of renal inv olv ement by ly mphoma is a perinephric rind of sof t t issue (F ig. 18- 55) around t he kidney w it hout a f oc al parenc hy mal lesion. T he sof t t issue has P.1268 a low at t enuat ion, and c ommonly direc t ly inv ades t he renal parenc hy ma. T he perinephric adenopat hy may c ompress adjac ent renal hilar st ruc t ures. T he kidney parenc hy ma may appear af f ec t ed t hrough direc t inv olv ement by perirenal t umor or renal hilar mass (433).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2733

18 - The Kidney and Ureter F igure 18- 54 Ly mphoma inf ilt rat ing t he renal hilum. Inf ilt rat iv e ly mphoma (* )

on c ont rast ed CT is usually less enhanc ed t han t he renal parenc hy ma and may c losely resemble T CC.

Anot her less c ommon appearanc e is dif f use inf ilt rat iv e inv olv ement of t he kidney (F ig. 18- 56) (192). In t his c ase, t here may be dif f use renal enlargement by a low - at t enuat ion inf ilt rat iv e mass. T he mass unif ormly expands t he kidney , w it h or w it hout a f oc al exophy t ic lesion (418). T here is usually predominant inv olv ement of t he renal medulla, w it h relat iv e sparing of t he c ort ic al margins. T he mass usually inv olv es t he renal hilum, and enc asement of t he renal v essels may result in dec reased renal enhanc ement (451). T he morphologic appearanc e of ly mphoma on MRI has many similar c harac t erist ic s t o CT . T he v arious pat t erns of ly mphomat ous renal inv olv ement c an be w ell demonst rat ed on MRI in a pat ient w it h a c ont raindic at ion t o CT . Renal ly mphoma is generally slight ly hy point ense t o t he renal parenc hy ma on non- enhanc ed T 1- w eight ed imaging. On T 2- w eight ed images, t he lesions are mildly hy perint ense relat iv e t o t he renal parenc hy ma. T here is mild het erogeneous enhanc ement of t he t umors, but t he amount of enhanc ement is muc h less t han t hat of t he surrounding parenc hy ma on T 1- w eight ed images af t er int rav enous gadolinium c ont rast (451). Primary renal ly mphoma is a f orm of NHL t hat arises direc t ly f rom t he renal parenc hy ma. Primary renal ly mphoma is ext remely rare bec ause t he normal kidney is f ree of ly mphat ic t issue (83,481). It present s w it h ac ut e renal f ailure or possibly abdominal pain (80). T he t umor is aggressiv e w it h rapid progression (108,440). How ev er, renal f unc t ion may ret urn af t er sy st emic t herapy . CT of primary renal NHL demonst rat es enlargement of t he kidney . Of t he f ew report ed c ases, 43% demonst rat ed bilat eral renal inv olv ement (108). Anot her ext remely rare hemat ologic malignanc y of t he kidney is c hronic ly mphoc y t ic leukemia. How ev er, t here is renal inv olv ement in as many as 90% of c ases of t his rare malignanc y . T his renal disease may be assoc iat ed w it h membranous glomerulonephit is and oc c asionally w it h renal f ailure (108).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2734

18 - The Kidney and Ureter

F igure 18- 55 Perinephric ly mphoma. Bilat eral perinephric rinds of sof t t issue densit y surround t he c ort ex of bot h kidney s on c ont rast ed CT .

F igure 18- 56 Ly mphoma dif f usely inf ilt rat ing and expanding t he kidney . On c ont rast ed CT , t he inf ilt rat iv e, hy podense c ent ral renal mass (ar r ow s) enlarges t he kidney w it h only minimal c ort ic al margin disrupt ion, similar in appearanc e t o inf ilt rat iv e T CC.

Metastases Met ast ases t o t he kidney most c ommonly are seen in t he set t ing of ot her met ast at ic disease (380). Renal met ast ases are present in approximat ely 10% t o 20% of pat ient s, depending on t umor t y pe (2,388). Exc luding ly mphoma and leukemia, t he most c ommon primary sit es f or renal met ast ases inc lude lung, c olon, and breast c arc inoma; melanoma; and reproduc t iv e organ malignanc ies suc h as t est ic ular or ov arian c arc inoma. Melanoma, w hen present , f requent ly

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2735

18 - The Kidney and Ureter met ast asizes t o t he kidney s, but it is less c ommon t han t he ot her t y pes of primary malignanc ies (58,145). Met ast ases t o t he kidney are usually asy mpt omat ic and are disc ov ered on imaging st udies (88,380). Rarely , pat ient s w it h renal met ast ases may hav e hemat uria (88). Met ast at ic disease t o t he kidney usually represent s hemat ogenous spread of disease, but it rarely may be t he only sit e of met ast asis (32,88). CT is v ery sensit iv e f or renal met ast ases (88). T he most c ommon appearanc e of renal met ast at ic disease is usually mult if oc al small renal masses (F ig. 1857), and t hey may inv olv e bot h kidney s (219). How ev er, solit ary renal

met ast ases are not unc ommon (88). Renal met ast ases are t y pic ally hy podense and do not c ommonly demonst rat e hy perenhanc ement (219). T he lesions measure 20 t o 40 HU on nonenhanc ed CT images and hav e minimal enhanc ement af t er int rav enous c ont rast of 5 t o 15 HU (88). Large renal lesions may be assoc iat ed w it h breast , lung, or c olon c arc inoma met ast ases, and t hose f rom c olon c arc inoma of t en disrupt t he renal c ort ic al margins (88). Inv asion of P.1269 t he perinephric spac e by a renal met ast asis is seen in met ast ases f rom melanoma or lung c arc inoma (88,551). T his t y pe of perirenal met ast at ic disease usually represent s ly mphat ic spread. Dif f use inf ilt rat iv e met ast ases may also oc c ur (32,388). Hemorrhagic renal met ast ases are most c losely assoc iat ed w it h melanoma primaries but may oc c ur w it h ot her primaries, suc h as pheoc hromoc y t omas and leiomy osarc omas (145).

F igure 18- 57 Met ast ases. Cont rast ed CT in a pat ient w it h lung c arc inoma has mult iple hy podense f oc al lesions t hat are c onsist ent w it h met ast at ic disease.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2736

18 - The Kidney and Ureter In t he set t ing of a know n malignanc y , renal met ast asis is muc h more c ommon t han RCC, but rarely t here is a c linic al quest ion of RCC v ersus met ast asis (88). Renal met ast ases are bilat eral in more t han 50% of pat ient s (535). Solit ary met ast asis may resemble RCC, but RCC t y pic ally has more nec rosis. Ot her f indings, suc h as hy perenhanc ement and renal v ein t hrombosis, help

suggest RCC ov er met ast asis (32,145,380). In our experienc e, t he marginat ion of met ast ases is of t en less w ell- def ined t han is seen in RCC. How ev er, in t he set t ing of a single renal lesion in a pat ient w it h rec ent malignanc y , t he c linic al quest ion is import ant . T his is bec ause t he t herapy f or renal c ell c arc inoma is of t en dif f erent f rom t he t herapy f or met ast at ic disease. T here has been inc reased use of radiof requenc y ablat ion t ec hniques f or t he t reat ment of an isolat ed renal mass. T his is more c ommonly used t o t reat a small renal c ell c arc inoma or rarely an isolat ed met ast asis (162). In t he set t ing of renal met ast ases, t he t reat ment w ould likely be palliat iv e.

Renal Sarcoma Renal sarc omas hav e sev eral dif f erent c ell t y pes and may arise f rom t he renal parenc hy ma or t he c apsule (F ig. 18- 58). T hey are most c ommon in pat ient s more t han 40 y ears of age, and t hey present w it h hemat uria, abdominal dist ension, w eight loss, or pain (461). Leiomy osarc oma is t he most c ommon t y pe of renal sarc oma, c omposing as many as half of renal sarc omas (140). T hey are c ommonly loc at ed in t he ret roperit oneum and may be loc at ed in t he perinephric spac e (277). T hese t umors are t reat ed w it h surgic al resec t ion but generally hav e a poor prognosis (321,478). On CT , t hese t umors are het erogeneous. F ibrous t issue c omponent s hav e delay ed enhanc ement , and spindle c ell c omponent s exhibit early enhanc ement . On MRI, t he t umors hav e low T 1 signal w it h mixed areas of high and low signal on T 2- w eight ed sequenc es.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2737

18 - The Kidney and Ureter

F igure 18- 58 Primary renal sarc oma. F oc al homogenous mass on c ont rast ed CT is c ent ered bey ond t he expec t ed margin of t he renal c ort ex. T he exophy t ic nat ure of t he mass should suggest t he diagnosis of a c apsular sarc oma.

Liposarc oma of t he kidney usually arises f rom t he c apsule and may present w it h mass, pain, or w eight loss, w it hout hemat uria (62). On CT , liposarc omas appear as a ret roperit oneal mass t hat c ont ains areas of mac rosc opic f at . Perinephric t umors are usually large, av eraging more t han 10 c m in diamet er. T he t umors are generally hy pov asc ular. A t umor c apsule may be present , and t he t umor may displac e t he kidney (236). Inv asion of t he renal parenc hy ma is not t y pic al. Also, liposarc oma of t he renal parenc hy ma is ext remely rare (326); t heref ore, no renal c ort ic al def ec t should exist . Unlike AMLs, liposarc omas are relat iv ely av asc ular and w it hout enlarged v essels (236). Diagnosis of perinephric liposarc oma on CT relies on dif f erent iat ing it f rom AML by not ing t he absenc e of enlarged v essels emanat ing f rom t he kidney as w ell as t he absenc e of a low - at t enuat ion renal c ort ic al def ec t assoc iat ed w it h AMLs (236). Clear c ell sarc oma of t he kidney is a rare but aggressiv e neoplasm t hat is most c ommon in neonat es and y oung c hildren. It present s w it h hemat uria, abdominal dist ension, or w eight loss/let hargy (167). T his t umor met ast asizes pref erent ially t o bone, as c ompared w it h ot her renal neoplasms (24). It may also met ast asize t o t he liv er, nodes, and lung. T reat ment usually requires a c ombinat ion of surgery and sy st emic t herapy . On CT , t he t umors are large and het erogeneous and enhanc e less t han t he normal renal parenc hy ma (167). Mult iple small f oc i are c ommon. Nec rosis, hemorrhage, and c alc if ic at ion may be present (167).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2738

18 - The Kidney and Ureter P.1270 Sarc omat oid RCC is a t umor c omprising RCC and T CC element s (140) and may

be dif f ic ult t o dif f erent iat e f rom sarc oma. T he CT appearanc e is similar t o t he pat t ern of c lear c ell renal c arc inoma (461).

Wilms Tumor Wilms t umor is a c ommon renal t umor in t he pediat ric populat ion. T he t umor most c ommonly oc c urs in c hildren aged 3 t o 4 y ears (77) and present s as a palpable abdominal mass. In some c ases, Wilms t umor has been assoc iat ed w it h WAGR sy ndrome (Wilms, aniridia, GU abnormalit ies, ret ardat ion), DRASH sy ndrome (Wilms, c ongenit al nephropat hy , pseudohermaphrodit ism), or Bec kw it h- Wiedemann sy ndrome (omphaloc ele, mac roglossia, gigant ism, mac rosomia, hemihy pert rophy ) (311). On CT , Wilms t umor appears as a f oc al solid renal mass w it h an appearanc e similar t o t hat of renal c ell c arc inoma. T he mass t y pic ally enhanc es het erogeneously and may exhibit areas of c y st ic c hange or nec rosis (416)(F ig. 18- 59). T here may be perinephric ext ension by t he mass and met ast at ic adenopat hy may be present (77)(151). Vasc ular inv asion by t he t umor has been f requent ly desc ribed (77). Unlike neuroblast omas, Wilms t umor does not usually enc ase t he aort a (311). Calc if ic at ions are rare. Met ast ases most c ommonly inv olv e t he lungs (178). On MRI, Wilms t umors demonst rat e mildly low T 1- signal and high T 2- signal c harac t erist ic s. Areas of nec rosis may result in het erogeneous signal w it hin t he mass and het erogeneous enhanc ement . MRI is able t o demonst rat e renal v ein and IVC inv olv ement bet t er t han CT does, and c oronal images may be usef ul (544).

Collecting Duct Carcinoma Collec t ing duc t c arc inoma (CDC), also know n as Bellini duc t c arc inoma or renal medullary c arc inoma, is a rare t umor t hat arises f rom t he c ells lining t he epit helium of t he dist al c ollec t ing t ubules of t he kidney (532). T he t umor usually present s w it h hemat uria, pain, or w eight loss (390). It is more c ommon in men t han w omen (125) and c ommonly oc c urs at mean age range of 50 t o 60 y ears, w it h a w ide age range (393). It is an aggressiv e t umor w it h a poor prognosis t hat usually has met ast at ic disease at t he t ime of diagnosis (116). Chao et al. not ed t hat 83% of pat ient s present ed w it h st age IV disease (74). Nodal met ast ases and lung met ast ases oc c ur in 78% and 27% of c ases,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2739

18 - The Kidney and Ureter respec t iv ely (390). Ot her c ommon sit es of met ast ases inc lude t he adrenal

gland and liv er (116). T herapy inc ludes nephrec t omy , but it is only c urat iv e in t he f ew pat ient s w ho hav e disease limit ed t o t he kidney (12,74). In pat ient s w it h met ast ases, t he median surv iv al af t er surgery is 11 t o 16 mont hs (12,74).

F igure 18- 59 Wilm's t umor w it h nephroblast omat osis. Cont rast ed CT in a 3y ear- old c hild demonst rat es a markedly het erogeneous solid and c y st ic mass expanding t he lef t kidney . Mult iple small lesions are present in t he right kidney . (Court esy of St uart A. Roy al).

On CT , t he mass is a solid or c omplex solid and c y st ic mass in t he c ent ral port ion of t he kidney . T he t umor usually inv olv es t he renal pelv is, but it may also c ommonly grow int o t he c ort ex or ev en dist ort t he renal margins. T he t umor may be inv asiv e and/or expansile (158,393). In one st udy , punc t at e or rim c alc if ic at ions w ere present in 4 of 17 c ases (393). On nonc ont rast CT , t he t umor oc c asionally w as mildly hy perdense t o t he rest of t he c ort ex. Af t er int rav enous c ont rast , t he t umor w as hy podense t o t he normal parenc hy ma, w it h only mild t o moderat e enhanc ement . T he right kidney w as more c ommonly inv olv ed, in 82% of c ases. Met ast at ic disease, usually adenopat hy , w as v isible on CT in 41% of pat ient s (393). On MRI, CDC usually is a c ent ral renal mass w it h T 1 signal t hat is isoint ense t o normal renal parenc hy ma unless t here are c y st ic c omponent s t hat are hy point ense. On T 2- w eight ed imaging, low T 2 signal relat iv e t o t he parenc hy ma is present . No pseudoc apsule is v isible (393). T he low T 2 signal is not t y pic al of RCC and should suggest t he diagnosis of CDC (393). On gallium-

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2740

18 - The Kidney and Ureter 67 radiosc int igraphy , t he t umor may hav e upt ake, and t his should prompt c onsiderat ion of t he diagnosis (492). Renal medullary c arc inoma (RMC) is a rare, dist inc t iv e t umor w it h an aggressiv e nat ure similar t o t hat of CDC. It oc c urs in y oung Af ric an- Americ an

c hildren and adult s, w it h a male predominanc e, and c ommonly has met ast ases present at t he t ime of present at ion (15,498). RMC oc c urs in higher assoc iat ion w it h sic kle c ell t rait or, rarely , disease (498). T he most c ommon present at ion is hemat uria, pain, or mass (498). Like CDC, t he mass is t y pic ally c ent ral and it also has a predilec t ion f or t he right kidney (in 82% of pat ient s) (566). It is a hy podense c ent ral renal mass and t here may be assoc iat ed adenopat hy . Most pat ient s do not respond t o t herapy , and surv iv al is less t han 16 mont hs (498).

BENIGN RENAL LESIONS Oncocytoma Renal onc oc y t oma is a benign t umor (349,424). It is a solid t umor t hat has spec if ic genet ic dif f erenc es f rom renal c ell c arc inoma (75). It appears as a solid, enhanc ing mass P.1271 w it h many c harac t erist ic s t hat are similar t o t hose of RCC (F ig. 18- 60). In f ac t , t he appearanc e of renal onc oc y t oma, w hen t y pic al, c annot be dif f erent iat ed f rom t hat of RCC. T hese lesions v ary in size and oc c ur in a w ide range of pat ient ages. Renal onc oc y t omas are more c ommon in men (82,389,424). Most onc oc y t omas are asy mpt omat ic (approximat ely 80%), but a f ew may present w it h hemat uria, pain, or mass (424). T hey are unc ommon, but t he inc idenc e of renal onc oc y t oma is higher in inc ident ally disc ov ered renal masses, as c ompared w it h pat ient s w ho hav e urinary sy mpt oms (389).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2741

18 - The Kidney and Ureter

F igure 18- 60 Small exophy t ic onc oc y t oma. Prec ont rast (A) and c ont rast ed (B) CT show a small enhanc ing c ort ic al mass dist ort ing t he renal margin, diagnosed as onc oc y t oma on pat hology . T he appearanc e is not dist inguishable f rom RCC.

Rarely , t he t umors may be mult iple and bilat eral (9,531), but nephron- sparing surgery is possible ev en in t hese c ases (398). Met ac hronous lesions may oc c ur in 4% of pat ient s (119). Bilat eral renal onc oc y t omat osis (F ig. 18- 61) is ext remely rare (3). On CT , onc oc y t omas are t y pic ally solid, w ell- marginat ed t umors t hat are slight ly hy podense t o t he rest of t he renal parenc hy ma on nonenhanc ed images (406,514). T hey t y pic ally show homogeneous enhanc ement af t er int rav enous c ont rast . Alt hough onc oc y t omas are more c ommonly homogeneous t han renal c ell c arc inomas are, a signif ic ant number of renal c ell c arc inomas hav e a homogeneous appearanc e (115). A c apsule may be present around t he t umor (22). Some lesions may exhibit a c ent ral sc ar t hat is low at t enuat ion w it h a branc hed appearanc e, regardless of lesion size (273). T he sc ar is t y pic ally nonenhanc ing (294). Unf ort unat ely , c ent ral nec rosis assoc iat ed w it h RCC may oc c asionally mimic t he c ent ral sc ar of a renal onc oc y t oma (115,303). Renal c apsular pat hologic inv asion int o t he perinephric f at oc c urs in 11% of c ases (9). Current ly , t here is no spec if ic CT f inding t o dif f erent iat e onc oc y t oma f rom RCC (424). T heref ore, in t he absenc e of prev iously doc ument ed onc oc y t oma or know n st abilit y of t he lesion, surgery is generally perf ormed f or t hese lesions. How ev er, nephron- sparing surgery should be c onsidered. An onc oc y t oma w it h at y pic al f eat ures does not hav e a signif ic ant ly dif f erent out c ome but should

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2742

18 - The Kidney and Ureter

be c losely f ollow ed (424). T here should be no adenopat hy or v asc ular inv asion assoc iat ed w it h t he mass, bec ause it is a benign neoplasm. T he presenc e of a c ent ral sc ar w it h absenc e of c alc if ic at ion, nec rosis, or hemorrhage should suggest t he diagnosis, alt hough t here is some ov erlap w it h small RCCs (19). T he MRI appearanc e of renal onc oc y t oma is t y pic ally hy point ense t o normal renal parenc hy ma on nonenhanc ed T 1- w eight ed images. How ev er, approximat ely 27% may be isoint ense on T 1 (190). T he lesions enhanc e homogeneously af t er int rav enous gadolinium c ont rast administ rat ion and may exhibit a spoke- w heel pat t ern of c ent ral enhanc ement (228). T here is usually high signal int ensit y of t he lesion on T 2- w eight ed images (190). When t he c ent ral sc ar is present , it is usually hy point ense on T 2- w eight ed sequenc es, as opposed t o t he high T 2 signal of nec rosis (190). T he MRI c harac t erist ic s of renal onc oc y t oma c annot be reliably dif f erent iat ed f rom RCC (19,405). Perc ut aneous biopsy of renal onc oc y t oma may be unable t o dif f erent iat e it f rom RCC (54,75). Dif f erent iat ion of onc oc y t oma and c hromophobe RCC is espec ially dif f ic ult (75). Bec ause t he c onf irmat ion of t he benign nat ure of t en c annot be obt ained, surgic al exc ision may be nec essary . T here is also an inc reased assoc iat ion of c lear c ell c arc inoma in t hese pat ient s in eit her kidney (301).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2743

18 - The Kidney and Ureter

F igure 18- 61 Mult iple bilat eral onc oc y t omas. On c ont rast ed CT (A, B), numerous enhanc ing renal masses enlarge t he kidney s w it hout dist ant met ast ases. Axial T 2- w eighed (C ) and c oronal T 1 c ont rast ed (D) images of t he kidney s hav e appearanc e t hat is indist inguishable f rom mult if oc al RCC.

P.1272 Renal adenoma is a small solid renal t umor t hat is also indist inguishable f rom RCC. T he lesions exhibit enhanc ement af t er int rav enous c ont rast , similar t o RCC or onc oc y t oma. Ot her solid enhanc ing renal masses, suc h as small solid renal f ibromas, are less c ommon. Renal leiomy oma is anot her rare lesion t hat may hav e a solid appearanc e and enhanc ement .

Angiomyolipoma Angiomy olipomas are c ommonly isolat ed sporadic t umors or assoc iat ed w it h t uberous sc lerosis (T S) (286). Sporadic AMLs w it hout T S are c ommonly det ec t ed in f emales during t he f if t h t o sev ent h dec ade or lat er and are more

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2744

18 - The Kidney and Ureter of t en larger and solit ary t han t hose f ound assoc iat ed w it h sy ndromes

(286,506). T uberous sc lerosis is t he most c ommonly assoc iat ed sy ndrome and c onsist s of ment al ret ardat ion, seizures, and t y pic al skin lesions. Mult iple angiomy olipomas (F ig. 18- 62) should suggest t he diagnosis of T S, as desc ribed earlier in t his c hapt er. Approximat ely 80% of pat ient s w it h T S hav e angiomy olipomas (185). How ev er, only 20% of c ases of angiomy olipoma subsequent ly y ield a diagnosis of T S. Angiomy olipomas may be rarely assoc iat ed w it h neurof ibromat osis- 1, v on Hippel- Lindau, or ADPKD. Angiomy olipoma is a c ommon benign renal mass and is det ec t ed as an inc ident al f inding on imaging or result ing f rom sy mpt oms in t he set t ing of lesion hemorrhage. Pat ient s w it hout T S are more of t en sy mpt omat ic (483). Signs of hemorrhage inc lude pain or ev idenc e of shoc k (397).

F igure 18- 62 Angiomy olipoma. Cont rast enhanc ed CT show s t hree t y pes of AML in pat ient w it h t uberous sc lerosis—f at t y int rarenal (ar r ow ), lipid poor (ar r ow head), and “ mushroom” (c ur v ed ar r ow ).

P.1273 On sonography , lesions are generally ec hogenic , bec ause of t he presenc e of f at . CT is generally t he most ac c urat e imaging t ec hnique f or det ec t ion and c harac t erizat ion of angiomy olipomas. T he lesions are usually low at t enuat ion w it h f at measurement s (F ig. 18- 63), and t he presenc e of gross f at is c harac t erist ic f or t hese lesions. T he ROIs of t hese lesions are t y pic ally less

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2745

18 - The Kidney and Ureter t han - 10 HU (48). T hin slic es are nec essary t o demonst rat e f at in small AMLs bec ause of v olume av eraging. Higher spec if ic it y c an be obt ained using t hreshold measurement s of - 15 t o - 30 HU. On CT , t he f at at t enuat ion of an AML may be int erposed w it h solid c omponent s. A subset of lesions w ill not meet f at at t enuat ion c rit eria bec ause of v olume av eraging or int rat umoral hemorrhage (286). Ot her AMLs do not meet f at at t enuat ion c rit eria bec ause t hey are relat iv ely f at - poor and appear denser t han t he surrounding renal

c ort ex on nonenhanc ed CT images (240). In one series of dense AMLs, t he f at c ont ent st ill ranged f rom 5% t o 15% (381). If t here are only small areas of f at w it hin t he lesion, t he diagnosis of AML is made, but rarely a w elldif f erent iat ed renal c ell c arc inoma c ould hav e t his appearanc e (200).

F igure 18- 63 Angiomy olipoma. Dif f use f at t y and sof t t issue densit ies are present in t his exophy t ic mass arising f rom t he renal margin. Not e t hat liposarc oma may also hav e t his appearanc e.

T he presenc e of ot her t y pic al AMLs in t he c ont ralat eral or ipsilat eral kidney helps in t he diagnosis of an at y pic al AML. AMLs are usually w ell marginat ed but do not hav e a t rue c apsule (236) (see F ig. 18- 62). T he lesion is usually at t he margin of t he kidney , and t he exophy t ic c omponent may expand, or “ mushroom,” bey ond a small hy podense w edge- shape def ec t in t he renal parenc hy ma (F ig. 18- 64). T his w edge def ec t is diagnost ic of angiomy olipoma (236). Large v essels may be ident if ied (236). T hese lesions are of t en v asc ular and show moderat e enhanc ement af t er int rav enous c ont rast . Int rat umoral

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2746

18 - The Kidney and Ureter aneury sms are c ommonly present , and aneury sms great er t han 5 mm in diamet er c orrelat e w it h inc reased risk of hemorrhage (558).

Approximat ely 58% t o 75% of t hese lesions w ill grow ov er t ime (287,483,526). How ev er, grow t h of an isolat ed P.1274 AML w it hout T S is muc h less c ommon t han w it h T S or in t he presenc e of mult iple lesions (287). Annual f ollow - up of asy mpt omat ic lesions is c ommonly perf ormed, unless t hey are larger t han 4 c m in diamet er, w it h inc reased risk of hemorrhage nec essit at ing semiannual ev aluat ion (376). How ev er, ev en small AMLs may rarely bleed (249). In small, isolat ed AMLs, less f requent f ollow - up examinat ions may be perf ormed onc e init ial size st abilit y is c onf irmed. F or large sy mpt omat ic lesions, embolizat ion may reduc e t he size of t he lesion and prev ent subsequent hemorrhagic risk (353,536)(see F ig. 18- 64).

F igure 18- 64 Angiomy olipoma w it h hemorrhage. T he int ermediat e densit y f luid w it hin t he AML is c onsist ent w it h hemorrhage (ar r ow heads), c ommon in large lesions. A renal not c h (ar r ow ) w it h v essels ent ering t umor and spont aneous hemorrhage c onf irm t he diagnosis of AML.

MRI c an also demonst rat e t he f at c omponent of an angiomy olipoma. On MRI, AMLs hav e a c harac t erist ic high T 1 signal int ensit y t hat is c onsist ent w it h f at signal. F at - sat urat ed T 1 images show a signif ic ant drop in signal int ensit y w it hin t he lesion, as c ompared w it h t he adjac ent renal parenc hy ma (228). Likew ise, opposed- phase T 1- w eight ed images show relat iv ely low signal int ensit y c ompared w it h in- phase T 1- w eight ed imaging. AMLs may display enhanc ement on T 1- w eight ed images af t er gadolinium c ont rast but are usually

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2747

18 - The Kidney and Ureter hy point ense t o t he surrounding parenc hy ma. T 2- w eight ed images may show moderat ely high int ensit y (228). Pat hology may hav e dif f ic ult y dif f erent iat ing a w ell- dif f erent iat ed liposarc oma

f rom angiomy olipoma. Oc c asional spindle c ells may y ield an inc orrec t diagnosis unless t he radiologic appearanc e is c onsidered, so t hat adequat e spec imen v olume is obt ained and ev aluat ed (536). In pat ient s w it h c oexist ent angiomy olipoma and onc oc y t oma, 36% w ere assoc iat ed w it h t uberous sc lerosis (394).

Non-neoplastic Benign Solid Renal Lesions Mult iple solid renal masses may be v isualized in non- neoplast ic sit uat ions. Sarc oidosis may oc c asionally hav e a pseudot umorous appearanc e w it h mult iple hy podense lesions inv olv ing bot h kidney s (306) (F ig. 18- 65). A solid renal lesion may be suspec t ed on ult rasound if t here are t w o areas of renal c ort ic al sc arring t hat are adjac ent t o an area t hat is spared f rom sc arring. A prominent renal c olumn of Bert in is a c ommon c linic al dilemma on ult rasound. T y pic ally , t his lesion may be separat ed f rom malignanc y based on it s similar enhanc ement t o t he rest of t he kidney on CT or MRI. T he lesion does not usually dist ort t he renal margin. T here is c ent ral ext ension of t he c olumn of Bert in in most pat ient s. It is import ant t o dif f erent iat e t hese lesions f rom renal malignanc y .

RENAL INFECTIONS Acute Infection In most c ases, c linic al signs suc h as f ev er, c hills, f lank pain or t enderness, and laborat ory result s suc h as leukoc y t osis (80%), py uria, and bac t eriuria indic at e t he presenc e of ac ut e urinary t rac t inf ec t ion. Urine c ult ures are posit iv e in 75% and blood c ult ures in 50% (49). In many c ases, no imaging is needed if t here is prompt c linic al response t o appropriat e ant ibiot ic s. If c linic al signs and sy mpt oms are unc lear, or if response t o t reat ment is poor, imaging is of t en perf ormed t o det ec t pot ent ial c omplic at ions. Urinary t rac t inf ec t ion (UT I) is best c onsidered as an int erac t ion bet w een host and pat hogen w it h a v ariet y of f ac t ors on bot h sides det ermining t he likelihood of a signif ic ant inf ec t ion. CT may be usef ul in t he set t ing of rec urrent UT Is f or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2748

18 - The Kidney and Ureter

det ec t ion of anat omic f ac t ors suc h as st ones, obst ruc t ion inc luding c ongenit al anomalies and bladder, or uret hral div ert ic ula.

F igure 18- 65 Renal sarc oidosis. Cont rast ed CT show s bilat eral hy podense renal masses (ar r ow s). T his is desc ribed as t he pseudot umorous f orm of renal sarc oid.

It is less import ant t o doc ument ac ut e py elonephrit is, w hic h almost inv ariably responds t o ant ibiot ic s, t han t o ident if y c omplic at ing f ac t ors suc h as hy dronephrosis, c alc uli, and absc ess. Int rav enous urography is rarely used f or serious inf ec t ions, bec ause it of t en f ails t o show any abnormalit y in c ases of ac ut e py elonephrit is or small renal absc esses; c onv ersely , sev eral dif f erent proc esses c an result in nonv isualizat ion of t he kidney , suc h as sev ere py elonephrit is, or py onephrosis (173,513). Alt hough sonography c an det ec t hy dronephrosis, c alc uli, and some absc esses, it is muc h less rev ealing t han CT (49,173,477). In many c ases of ac ut e py elonephrit is, sonography w ill appear normal alt hough CT show s def init e abnormalit ies (505). Alt hough radionuc lide sc int igrams are v ery sensit iv e t o renal c hanges result ing f rom inf ec t ion, t hey do not dist inguish t he v arious pat hologic proc esses in adult s. CT is usually t he most rev ealing imaging proc edure f or renal inf ec t ions. A v ariet y of t erms hav e been promulgat ed f or ac ut e bac t erial inf ec t ion of t he kidney , but ac ut e py elonephr it is is t he pref erred t erm (285,505,545,567). Ot hers t erms (suc h as ac ut e f oc al bac t er ial nephr it is and lobar nephr onia) hav e enjoy ed popular usage (505); how ev er, neit her pat hology P.1275

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2749

18 - The Kidney and Ureter nor t reat ment is dif f erent f rom w hat is c lassic ally c alled ac ut e py elonephrit is. T he CT f eat ures of ac ut e py elonephrit is are: (a) renal sw elling, produc ing enlargement of t he af f ec t ed kidney ; (b) f oc al hy poat t enuat ion; and (c ) mass ef f ec t . T here are round or w edge- shaped areas in t he parenc hy ma w hose at t enuat ion is normal, dec reased (bec ause of edema or nec rosis), or

oc c asionally inc reased (bec ause of hemorrhage) (421) on prec ont rast images. Af t er c ont rast , t hese areas show diminished enhanc ement c ompared t o normal parenc hy ma on early images (F ig. 18- 66) (49,173,477). T he w edge- shaped areas in f ac t do enhanc e, but muc h less t han normal parenc hy ma, as a result of edema or v asospasm c aused by t he inf ec t ion. On delay ed images up t o 24 hours, t here may be inc reased at t enuat ion w it hin, or at t he periphery of , t hese areas (233).

F igure 18- 66 Py elonephrit is w it h st riat ed nephrogram. Bilat eral sy mmet ric st riat ed nephrograms are present on c ont rast ed CT . T he sy mmet ric inv olv ement and lac k of perinephric st randing w ould be at y pic al f or inf ec t ion.

In some c ases, one or more f oc al areas of t he kidney are sev erely inv olv ed, w it h sparing of ot her regions (173,477). T here may be a single mass- like region as a result of sw elling result ing f rom edema (t his is f oc al py elonephrit is, f ormerly c alled ac ut e f oc al bac t erial nephrit is t o dist inguish it f rom neoplasm) (285) (F ig. 18- 67). Pat c hy dec reased enhanc ement may be limit ed t o t his f oc al mass. A f requent (77%) f inding in ac ut e inf ec t ions is t hic kening of t he renal f asc ia and t hic kening of t he sept a in t he perinephric spac e, a result of hy peremia and inf lammat ory edema (477). Despit e t reat ment w it h adequat e ant ibiot ic s, CT abnormalit ies may persist f or sev eral w eeks t o mont hs (476). Persist enc e of a f oc al mass may inc rease t he suspic ion of t umor, but it must be rec ognized as a possible sequela of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2750

18 - The Kidney and Ureter

inf ec t ion unt il f ollow ed f or up t o 6 mont hs (476). Wit h t he sev ere parenc hy mal inf ec t ion t hat c auses f oc al CT abnormalit ies, sc ar f ormat ion is not unc ommon, and polar or global at rophy may be seen (476). Emphy semat ous py elonephrit is (EPN) is c lassic ally c onsidered a pot ent ially lif e- t hreat ening, gas- f orming inf ec t ion of t he kidney . Cont ribut ing f ac t ors t o dev elopment of EPN are high t issue lev el of gluc ose, presenc e of gluc ose f erment ing bac t eria, poor v asc ular supply /poor t issue oxy gen t ension, impaired host immunit y , and obst ruc t ion (alt hough t his last is not an absolut e requirement ). Bec ause of t hese c ausat iv e f ac t ors, t his proc ess is usually seen in diabet ic s (229,377,427,530). Pat ient s may present w it h signs of ac ut e inf ec t ion, but of t en t hey are f ound c omat ose f rom diabet ic ket oac idosis. In f ac t t here are signs, sy mpt oms or laborat ory dat a t hat dist inguish pat ient s w it h EPN f rom t hose w it h ot her upper urinary t rac t inf ec t ions (462). Imaging is nec essary f or diagnosis.

F igure 18- 67 F oc al py elonephrit is. F oc al areas of diminished enhanc ement in t he renal c ort ex af t er int rav enous c ont rast are c onsist ent w it h py elonephrit is. Alt hough not show n here, f oc al areas of nonenhanc ement may be seen w it h early absc ess f ormat ion.

Alt hough in t he past diagnosis may hav e been made using IVU (mot t led gas in nonf unc t ioning kidney ), sev eral st udies hav e show n t hat CT is t he best means f or diagnosis and has also demonst rat ed some f eat ures not rec ognizable by eit her IVU or US (462,540,541,507). CT demonst rat es not only t he presenc e and loc at ion of gas, but also presenc e of perinephric f luid c ollec t ions or renal or perirenal absc esses (F ig. 18- 68). Wan dif f erent iat ed t w o t y pes of EPN.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2751

18 - The Kidney and Ureter T y pe 1, “ c lassic ” EPN, is c harac t erized by int raparenc hy mal gas (w hic h

may be st reaky , mot t led, bubbly , or loc ulat ed) but no perinephric f luid or f oc al absc ess. In c lassic EPN, gas may ext end t o t he subc apsular, perinephric , and pararenal spac es and may c ross t o t he c ont ralat eral ret roperit oneal spac es, ev en w hen t he ot her kidney is not inf ec t ed. T y pe 2 EPN w as c harac t erized by “ presenc e of renal or perirenal f luid in assoc iat ion w it h bubbly or loc ulat ed gas or by gas in c ollec t ing sy st em” (F ig. 18- 69). In a c linic al series, Wan f ound 69% mort alit y in t y pe 1 EPN, but only 18% in t y pe 2 (540). Negat iv e prognost ic f ac t ors inc luded t y pe 1 EPN, sev ere t hromboc y t openia, impaired renal f unc t ion, and high lev els of hemat uria. Nephrec t omy w as required in 16 and drainage in 13; all but 1 w ere diabet ic .

F igure 18- 68 Emphy semat ous py elonephrit is in a t ransplant kidney . T w o unc ont rast ed CT images of t ransplant ed kidney (A, B) in t he right low er quadrant show sev ere dist ort ion and dest ruc t ion of t he kidney w it h large amount s of gas in t he expec t ed regions of renal c ort ex (ar r ow s). Gas also t rac ks in t he abdominal w all.

P.1276 A series of 20 pat ient s show ed t y pic al c harac t erist ic s of EPN in t he modern era (462). Diabet es w as present in 80%, 75% w ere f emale, mean age w as 55 y ears, and lef t kidney w as slight ly more c ommon (60%). Only 50% had obst ruc t ion. Inf ec t ious agent w as Esc her ic hia c oli in 70%, mort alit y w as 20%, but nephrec t omy w as perf ormed in all. While t he def init ion of t y pe 2 EPN inc ludes w hat may be c alled “ emphy semat ous py elit is,” t his subset of gas- f orming renal inf ec t ions should be rec ognized as dist inc t . In a small series

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2752

18 - The Kidney and Ureter of 5 pat ient s w it h gas in t he c ollec t ing sy st em but no perinephric f luid, t here w as no mort alit y . F urt hermore, only 1 of t he 5 had diabet es; 4 of t he 5 had urinary lit hiasis (431).

F igure 18- 69 Emphy semat ous py elonephrit is—Gram negat iv e rods, Ent erobac t er. Cont rast ed CT of t he right kidney demonst rat es gas w it hin t he c ollec t ing sy st em of t he lef t kidney . T he nephrogram has a pat c hy appearanc e.

T he import anc e of t hese rec ent st udies is t hat ov erall mort alit y is not as high as in t he past but t hat EPN remains lif e t hreat ening. T he presenc e or absenc e of f luid and it s c harac t er may be as import ant as t he presenc e and loc at ion of gas. Parenc hy mal gas in a nonf unc t ioning kidney w it h no assoc iat ed f luid probably remains t he most sev ere f orm. Gas in t he c ollec t ing sy st em w it h no f luid is t he least sev ere and c an be t reat ed medic ally (w it h relief of obst ruc t ion if needed). How ev er, gas in assoc iat ion w it h perinephric f luid or absc ess is int ermediat e sev erit y , and if t reat ed c onserv at iv ely should be f ollow ed c losely w it h CT . Bec ause c arbon dioxide (CO 2) is rapidly absorbed, t here should be rapid dec rease in t he gas if t here is a good response t o medic al t herapy , and persist ent gas on f ollow - up CT indic at es ongoing inf ec t ion (340). If t he gas and f luid do not improv e w it h ant ibiot ic s and drainage, nephrec t omy may st ill be required. Py onephrosis result s f rom inf ec t ion of a hy dronephrot ic kidney . T his may present as eit her an ac ut e or a c hronic inf ec t ion, w it h up t o 15% of pat ient s being af ebrile (563). T hus, t his ent it y must be dist inguished f rom ac ut e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2753

18 - The Kidney and Ureter

py elonephrit is, renal absc ess, and XGP. Urography is of lit t le use, bec ause t he kidney is usually nonf unc t ioning. Sonography is usually diagnost ic and c an guide perc ut aneous aspirat ion and nephrost omy plac ement . How ev er, CT is of t en used in suc h P.1277 a set t ing. CT show s dilat ion of t he c ollec t ing sy st em and poor exc ret ion. T hic kening of t he pelv ic w all and of Gerot a's f asc ia is c ommon (159); inc reased at t enuat ion or het erogeneit y of t he pelv ic c ont ent s may be seen but is rare. CT also c an show t he c ause of t he obst ruc t ion. T he role of MRI in ev aluat ion of ac ut e renal inf ec t ion is limit ed t o pat ient s w ho eit her c annot undergo a c ont rast - enhanc ed CT st udy or hav e equiv oc al CT examinat ion result s. Lit t le experienc e exist s w it h MRI in t he diagnosis of urinary t rac t inf ec t ions. It is more dif f ic ult w it h MRI t han w it h CT t o produc e good images of v ery ill pat ient s bec ause of t he susc ept ibilit y of MRI t o mot ion. T he c hanges result ing f rom py elonephrit is are not spec if ic , w it h v ariable het erogeneous enhanc ement of parenc hy ma on breat h- hold GRE T 1- w eight ed images af t er Gd- DT PA. Renal absc esses may be demonst rat ed as low signal, nonenhanc ing regions on c ont rast - enhanc ed T 1- w eight ed images, w it h v ariable surrounding enhanc ing w all and perinephric inf lammat ory st randing (55).

RENAL ABSCESS Renal absc ess is inc reasingly unc ommon, largely bec ause most ac ut e inf ec t ions are ef f ec t iv ely t reat ed. Most renal absc esses c urrent ly are a result of an asc ending inf ec t ion and are usually c aused by gram- negat iv e urinary pat hogens, part ic ularly E. c oli (36%) (49,155). Less t han 10% result f rom hemat ogenous seeding usually c aused by St aphy loc oc c us (49,155). Renal absc esses also may be a c omplic at ion of t rauma, surgery , c ont iguous spread f rom ot her organs, or ly mphat ic spread (49,278). In most c ases t oday , a renal absc ess result s f rom breakdow n and c oalesc enc e of mic roabsc esses due t o ac ut e py elonephrit is t hat is inadequat ely t reat ed. An absc ess is a nec rot ic , dev asc ularized c av it y , of t en f illed w it h pus. Alt hough many pat ient s present w it h ac ut e inf ec t ion, t he diagnosis is somet imes obsc ure if t he pat ient has only v ague sy mpt oms suc h as f lank pain, w eakness, and w eight loss (49,155,455). F ev er is absent in one t hird of pat ient s, a normal urinaly sis is f ound in one f ourt h, and posit iv e urine c ult ures are present in only one t hird of pat ient s (351). T hus, renal absc ess (F ig. 18- 70) must be dist inguished bot h

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2754

18 - The Kidney and Ureter

f rom ac ut e py elonephrit is and f rom renal t umors. CT is t he best proc edure f or t his ev aluat ion, ident if y ing 96% of absc esses in t w o large series (155)(477). Alt hough sonography w ill ident if y an abnormalit y , it is less sensit iv e t han CT (155,477), and t he appearanc e may not be dist inguishable f rom a renal neoplasm. A rare t y pe of absc ess, sec ondary t o ac t inomy c osis, may also mimic a renal mass. It c an hav e low signal int ensit y on T 1- and T 2- w eight ed MRI w it h a f oc al appearanc e (223). In many c ases of renal absc ess (50%), t he ent ire kidney is enlarged (477). In some, a f oc al mass bulges t he renal c ont our. Inf lammat ory c hanges in t he perinephric spac e and t hic kening of Gerot a's f asc ia are c ommon (77% and 42% , respec t iv ely ) (477). A f oc al low - at t enuat ion area (near w at er at t enuat ion) is seen on prec ont rast images; t here w ill be no enhanc ement in t he c ent er of t he lesion. Commonly t here is a t hic k, slight ly irregular and ill- def ined rind of enhanc ing t issue surrounding t he absc ess c av it y (F ig. 18- 71). T here may be sept at ions w it hin t he absc ess (F ig. 18- 72). T he remainder of t he kidney may be normal, or it may show c hanges of py elonephrit is. T he presenc e of gas in t he lesion is pat hognomonic of absc ess, but it is unusual.

F igure 18- 70 Py elonephrit is and renal absc ess on CT . Pat c hy enhanc ement of t he lef t kidney is present w it h liquif ac t iv e nec rosis in t he medullary port ion of t he kidney (ar r ow ). T he right kidney has a normal appearanc e.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2755

18 - The Kidney and Ureter

F igure 18- 71 Renal absc ess—Ent erobac t er Aerogenes. Cont rast ed CT of t he lef t upper pole demonst rat es poorly marginat ed c ollec t ion w it h ext ension t hrough t he c ort ex and marked t hic kening of perinephric f asc ia (ar r ow ). Changes of c hronic panc reat it is are not ed in t he t ail of t he panc reas.

F igure 18- 72 Mult iple renal and perirenal absc esses w it h loc ulat ion/sept at ions. On c ont rast ed CT , parenc hy mal loc ulat ed c ollec t ion

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2756

18 - The Kidney and Ureter (ar r ow ) has a separat e c omplex c ollec t ion in t he post erior perinephric spac e. Cult ure rev ealed Met hy c illin Resist ant St aphy loc oc c us aureus (MRSA).

P.1278 Perinephric absc ess has also dec lined in f requenc y in t he modern era. It is now unc ommon but st ill oc c urs, usually as ext ension of a renal inf ec t ion int o t he perinephric spac e. It is c harac t erized on CT as a disc ret e, loc ulat ed f luid c ollec t ion in t he perinephric spac e usually w it h a rec ognizable enhanc ing rim (F ig. 18- 73). It may be adjac ent t o a renal parenc hy ma absc ess and may c ont ain gas. Alt hough perinephric absc ess c arries a reput at ion of high mort alit y , based on prior experienc e of ov er 50% mort alit y (336), t he rapid av ailabilit y and ac c urac y of CT allow s f or earlier det ec t ion and c orrec t diagnosis. In a series of 25 pat ient s w it h perinephric absc ess, only 4 required nephrec t omy , and mort alit y w as only 12% (336). T he 10 pat ient s w it h absc esses smaller t han 1.8 c m w ere suc c essf ully t reat ed w it h ant ibiot ic s alone; 11 had ant ibiot ic s and perc ut aneous drainage w it h suc c essf ul out c ome.

F igure 18- 73 Perinephric absc ess—E. c oli. T hic k w alled c omplex c ollec t ion on c ont rast ed CT is sec ondary t o ext ension of a renal absc ess int o t he perinephric spac e. Renal absc ess may c ommonly ext end bey ond t he c ort ic al margins.

It is somet imes dif f ic ult t o dist inguish an indolent absc ess f rom a nec rot ic renal t umor (106). In suc h a c ase, perc ut aneous needle biopsy may be required. In general, onc e an absc ess is ident if ied, needle aspirat ion should be

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2757

18 - The Kidney and Ureter done f or def init iv e diagnosis, f or c ult ure, and f or plac ement of drains, w hic h has been show n t o improv e out c ome (278). Despit e t herapy , CT w ill show

sequelae of renal absc esses f or w eeks t o mont hs, espec ially if t reat ed w it hout drainage. F oc al sc arring of t en result s (476).

CHRONIC RENAL INFECTIONS T he c harac t erist ic c hanges of c hronic py elonephrit is on urography are also readily ident if ied w it h CT . A f oc al parenc hy mal sc ar ov erly ing a blunt ed c aly x indic at es t he diagnosis, w het her single or mult iple areas are inv olv ed. T his is dist inc t f rom sc arring relat ed t o inf arc t , in w hic h t he c aly x is not blunt ed. Xant hogranulomat ous py elonephrit is is an unc ommon c hronic inf ec t ion t hat has a spec if ic pat hologic appearanc e, t y pic ally oc c urring in an obst ruc t ed kidney . T here is ac c umulat ion of lipid- laden mac rophages (xant homa c ells) and a granulomat ous inf ilt rat e bec ause of t he f ailure of loc al immune response (198). In 85% of c ases, t he ent ire kidney is inv olv ed, but t he disease may be f oc al. CT is v ery usef ul, bec ause t he f indings on sonography and urography are nonspec if ic (175,198,207,387,529). On CT , XGP is assoc iat ed w it h (a) a large c ent ral c alc ulus, of t en a st aghorn; (b) enlargement of t he kidney (or of a segment ); (c ) poor or no exc ret ion of c ont rast int o t he c ollec t ing sy st em; and (d) mult iple f oc al low - at t enuat ion (- 10 t o +30 HU) masses sc at t ered t hroughout t he inv olv ed port ions of t he kidney (F ig. 18- 74). T he low at t enuat ion c ollec t ions represent dilat ed, debris- f illed c aly c es and xant homa c ollec t ions. T he c ollec t ions t hemselv es do not enhanc e, and t here is no exc ret ion of c ont rast , but t here is bright enhanc ement of t he rims of t he c ollec t ions bec ause of inf lammat ory hy perv asc ularit y . Alt hough XGP is usually f ound in t he set t ing of c hronic obst ruc t ion, of t en t he renal pelv is is less dilat ed t han might be expec t ed f or high- grade c hronic obst ruc t ion. Also, t he renal sinus f at is of t en oblit erat ed by inf lammat ion (387). Perinephric ext ension oc c urs in about 14% and is w ell show n on CT (89,175,207,529), f ist ulae may dev elop (494), and gas rarely may be seen. Some v ariat ions oc c ur: t he kidney may be small, and c alc uli may be absent , making it dif f ic ult t o dist inguish XGP f rom ot her inf ec t ions or neoplasm. Nephrec t omy is P.1279 indic at ed in any c ase, but part ial nephrec t omy c an be perf ormed f or t he f oc al f orm.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2758

18 - The Kidney and Ureter

F igure 18- 74 Xant hogranulomat ous py elonephrit is (XGP). A, B: On c ont rast ed CT , t he lef t kidney is enlarged, v ery poorly enhanc ing, and c ont ains a f ragment ed st aghorn c alc ulus. T he c ollec t ing sy st em is markedly dilat ed and dist ort ed by xant hogranulomat ous debris; perinephric st randing is present .

Renal t uberc ulosis (T B) is unc ommon, but it s f requenc y has rec ent ly been inc reasing bec ause of resist ant organisms and t he inc rease in pat ient s w it h AIDS. A v ariet y of f indings may be show n, depending on t he st age of inv olv ement (110,137,174,404). CT is c apable of demonst rat ing parenc hy mal masses and c av it ies, parenc hy mal sc arring, c alc if ic at ions, t hic kening of renal pelv is or uret er, hy dronephrosis or hy droc alic osis, aut onephrec t omy , and ext rarenal manif est at ions (F ig. 18- 75). Det ec t ion of mot h- eat en c aly c es and amput at ed inf undibulum may be bet t er show n by IVU, alt hough experienc e w it h mult idet ec t or CT U is limit ed. Eac h indiv idual f inding of renal T B is nonspec if ic , but a c ombinat ion of f indings c an be suggest iv e—in one st udy , c ases w it h parenc hy mal masses show ed at least one ot her f inding; t he most f requent c ombinat ion on CT w as hy dronephrosis or hy droc alic oses w it h parenc hy mal sc arring. T he “ aut onephrec t omy ,” a small nonf unc t ioning kidney w it h dif f use amorphous c alc if ic at ion, is easily rec ognized on CT . Demonst rat ion of a small hy dronephrot ic kidney w it h a c ont rac t ed and t hic k- w alled renal pelv is is also suggest iv e of T B. Marked t hic kening of t he w all of t he uret er or pelv is may be seen on CT . CT also is exc ellent f or demonst rat ing perirenal ext ension or f ist ulae t o adjac ent organs, suc h as t he c olon or duodenum.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2759

18 - The Kidney and Ureter

F igure 18- 75 Renal t uberc ulosis. Cont rast ed CT show s a dilat ed inf undibulum (c ur v ed ar r ow ) proximal t o a st ric t ure, t hic kening of t he proximal uret er w all (ar r ow ) and renal absc ess w it h peripheral c alc if ic at ions (ar r ow heads).

T he inc idenc e of f ungal inf ec t ions in t he kidney is also on t he rise w it h t he inc reasing populat ion of immune- c ompromised pat ient s, inc luding t ransplant rec ipient s, pat ient s w it h malignanc ies, and AIDS pat ient s (554). F ungi c an c ause py elonephrit is and renal absc ess w it h t he same CT appearanc e as bac t erial inf ec t ions (106,153). F ungal inf ec t ion is suggest ed w hen mult iple mic roabsc esses are seen in t he kidney , spleen, or liv er (460). Slough of urot helium, inf lammat ory c ells, and my c elia int o t he c ollec t ing sy st em c an f orm a f ungus ball. Suc h pat ient s of t en hav e poor renal f unc t ion, and c aref ul at t ent ion t o t he at t enuat ion of t he pelv ic c ont ent s is required t o rec ognize a f ungus ball on nonc ont rast CT . In t hese pat ient s, t he pelv is is dilat ed and f illed w it h mat erial of sof t t issue at t enuat ion, rat her t han w at er at t enuat ion. Malac oplakia is a v ery unc ommon c hronic inf ec t ion t hat c an af f ec t t he kidney , alt hough it is more c ommonly f ound in ot her organs, part ic ularly t he bladder. Renal malac oplakia is muc h more c ommon in w omen t han in men, and pat ient s are usually debilit at ed or immune suppressed; it c an oc c ur in renal t ransplant s. It result s w hen a bac t erial inf ec t ion, most of t en E. c oli, c annot be eradic at ed bec ause of a loc al immune f ailure, and a c hronic granulomat ous P.1280 inf lammat ory proc ess dev elops. T he proc ess is of t en mult if oc al, and it may be bilat eral. Mult iple sof t t issue masses of v ary ing size may be seen on CT (231). T hese lesions enhanc e less t han normal renal parenc hy ma af t er int rav enous c ont rast , but enhanc ement does oc c ur bec ause of t he inf lammat ory

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2760

18 - The Kidney and Ureter v asc ularit y . Hy dronephrosis, nephrolit hiasis, and lesional c alc if ic at ion are not seen. T here may be perinephric inv olv ement . If unif oc al, t he lesion c an mimic

RCC; w hen mult if oc al, met ast ases or ly mphoma may be c onsidered. Pat hologic examinat ion is of t en needed f or diagnosis; large hist ioc y t es (v on Hanseman c ells) and basophilic int rac y t oplasmic inc lusions (Mic haelis- Gut mann bodies) are pat hognomonic (231). Hy dat id disease is v ery unc ommon in Nort h Americ a, but it is endemic in part s of t he w orld and may be seen in immigrant s or t rav elers. T he kidney s are inv olv ed in only about 2% t o 3% of c ases (4). T he disease result s f rom inf est at ion by t he larv al f orm of Ec hinoc oc c us gr anulosus. Signs and sy mpt oms are nonspec if ic , inc luding f lank mass, hemat uria, dy suria, f ev er, and hy pert ension. T he c y st s may rupt ure int o t he c ollec t ing sy st em, and renal c olic may be a present ing sy mpt om due t o hy dat iduria (4). T he CT appearanc e may be c harac t erist ic , usually show ing a mult iloc ular c y st ic mass w it h mural c alc if ic at ion. T here may be enhanc ement of t he t hic k w alls. T he presenc e of small daught er c y st s w it hin t he main c y st is c harac t erist ic , and it is dif f erent f rom t he usual appearanc e of a c alc if ied RCC. How ev er, oc c asionally t here may be a nonc alc if ied uniloc ular c y st , w hic h may be dif f ic ult t o dist inguish f rom an inf ec t ed simple c y st (4). In pat ient s w it h AIDS, a number of c ondit ions c an af f ec t t he kidney s, and CT may be usef ul in demonst rat ing t hese diseases. Kaposi sarc oma, ly mphoma, or RCC may produc e renal masses in AIDS pat ient s (343). All t y pes of renal inf ec t ions, inc luding py elonephrit is, absc ess, f ungal inf ec t ions, and T B, are more c ommon in AIDS pat ient s. Opport unist ic inf ec t ious agent s, suc h as pneumoc y st is, My c obac t er ium av ium -int r ac ellular e, and c y t omegalov irus c an inv olv e t he kidney ; all of t hese c an produc e mult iple, small c alc if ic at ions sc at t ered t hroughout t he kidney s (343). Human immunodef ic ienc y v irus (HIV)assoc iat ed nephropat hy is most of t en seen in HIV pat ient s w ho are y oung, blac k men w it h a hist ory of int rav enous drug abuse. On CT , t he kidney s are normal t o large in size; t here may be a st riat ed nephrogram af t er int rav enous c ont rast (343). Renal replac ement lipomat osis is a quit e unusual proc ess t hat produc es a st riking CT appearanc e (220,369). It is assoc iat ed w it h c hronic inf ec t ion and c alc uli, c ommonly c ent ral and of t en obst ruc t ing (182,490,511). T he kidney may be large or small but is usually nonf unc t ioning. Most of t he renal parenc hy ma has been replac ed by f at , in many c ases leav ing only a ghost of a kidney c ont aining c alc uli. Pararenal f asc ia is t hic kened, and t here may be

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2761

18 - The Kidney and Ureter

f ist ulae. A f at t y mass c ausing displac ement of adjac ent st ruc t ures, suggest iv e of liposarc oma, c an also be seen (369). Papillary nec rosis c an result f rom a v ariet y of c auses and is assoc iat ed w it h UT I and diabet es, alt hough it may also be a result of v asc ular disease, hemoglobinopat hies and ot hers. Alt hough usually diagnosed w it h IVU in t he past , t here may be pot ent ial f or CT det ec t ion, alt hough f urt her inv est igat ion is needed. Use of ext remely f ine resolut ion MDCT U in exc ret ory phase is c apable of demonst rat ing blunt ed c aly c es and medullary c av it ies, but no large st udy has doc ument ed sensit iv it y and spec if ic it y of t his t ec hnique. One st udy report ed t hat early c hanges of papillary sw elling and diminished enhanc ement c ould be seen early in t he c ourse, best demonst rat ed in t he nephrographic phase. How ev er, only some of t hese progressed on f ollow - up IVU t o c lassic c hanges of papillary nec rosis, perhaps bec ause of suc c essf ul int erv ent ion (280).

URINARY OBSTRUCTION CT and sonography are usef ul imaging met hods f or t he det ec t ion of obst ruc t ion. Eac h has t he c apac it y t o v isualize kidney s w it h any degree of f unc t ion, bec ause t he v isualizat ion is not dependent on exc ret ion of c ont rast . More import ant , gas or bone does not impede CT v isualizat ion, unlike w it h sonography , so CT c an demonst rat e t he f ull lengt h of t he uret ers. CT c an display t he c hanges of ac ut e obst ruc t ion—sw elling, perirenal st randing, py eloc aliec t asis, and delay ed exc ret ion (F ig. 18- 76). T he c hanges of c hronic obst ruc t ion—renal parenc hy mal at rophy , hy dronephrosis, poor exc ret ion—are also w ell display ed. Det ec t ion of hy drouret eronephrosis is not dependent on exc ret ion of c ont rast , and t he t rue st rengt h of CT is it s abilit y t o show t he ent ire c ourse of t he uret er, t he point of c hange in c aliber of an obst ruc t ed uret er, and int rinsic c auses of obst ruc t ion suc h as high at t enuat ion st ones or uret eral t umors w it h sof t t issue at t enuat ion and post c ont rast enhanc ement . Ext rinsic c auses of obst ruc t ion suc h as ext rinsic t umors, ret roperit oneal f ibrosis, and ret roc av al uret er or c ongenit al anomalies suc h as ec t opic uret eroc oeles c an be easily seen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2762

18 - The Kidney and Ureter

F igure 18- 76 Obst ruc t ion of t he right uret er. Delay ed right renal enhanc ement is present on c ont rast ed CT c ompared t o lef t kidney . Not e t he right kidney is malrot at ed.

P.1281 One hallmark of c hronic obst ruc t ion is sy mmet ric at rophy of t he ent ire obst ruc t ed kidney (or one segment in uret eral duplic at ion), in c ont rast t o f oc al and irregular at rophy result ing f rom inf arc t s or c hronic py elonephrit is. Caref ul analy sis t hus allow s CT t o dist inguish t rue obst ruc t iv e dilat ion f rom some pot ent ial pit f alls. T he ot her hallmark is hy dronephrosis, w hic h is easily display ed on CT . Some pot ent ial pit f alls, suc h as ext rarenal pelv is, mult iple parapelv ic c y st s, post obst ruc t iv e dilat at ion, diuret ic st at e, bladder out let obst ruc t ion, and ot hers, may be av oided w it h enhanc ed sc ans, show ing eit her a normal exc ret ion pat t ern or t he c ollec t ing sy st em separat e f rom c y st s. Delay ed images may be helpf ul t o f ill t he c ollec t ing sy st em and uret ers. Alt hough not emphasized as a signif ic ant f inding in t he lit erat ure, uret eral jet s c an of t en be seen on CT , doc ument ing f low t o t he bladder as w it h sonography . MRI is also usef ul in det ec t ing or exc luding obst ruc t ion, alt hough w it h perhaps slight ly less spat ial resolut ion t han CT . It is c apable of demonst rat ing t he anat omic c hanges as desc ribed prev iously of ac ut e or c hronic obst ruc t ion. Wit h w at er- sensit iv e t ec hniques (f at - suppressed T 2, RARE t y pe sequenc es), not only c an t he dilat ed c ollec t ing sy st em and uret er be easily display ed, but t he perirenal edema and st randing t hat oc c ur w it h ac ut e obst ruc t ion c an also be seen. How ev er, det ec t ion of small c alc uli on MRI is more dif f ic ult t han on CT ; larger st ones may be indic at ed as a hy point ense f illing def ec t or menisc us

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2763

18 - The Kidney and Ureter at t he bot t om of a c olumned uret er. Magnet ic resonanc e urography (MRU)

t ec hniques hav e been dev eloped t hat hav e some pot ent ial f or diagnosis of t he presenc e and c ause of obst ruc t iv e uropat hy . In t he set t ing of c hronic obst ruc t ion w it h signif ic ant dilat at ion, T 2- sensit iv e t ec hniques are v ery usef ul (and w hen gadolinium c ont rast - enhanc ed t ec hniques limit ed by t he poor exc ret ion of t he c hronic ally obst ruc t ed kidney ). In t he set t ing of ac ut e obst ruc t ion, T 2 met hods are less ef f ec t iv e, and T 1- w eight ed gadoliniumenhanc ed met hods t o opac if y t he c ollec t ing sy st em and uret er may be more usef ul. How ev er, t he minimally dilat ed or normal sy st em may be less w ell display ed unless some diuret ic agent s (e.g., int rav enous f luid or f urosamide) are used (37,372). F or c omplet e analy sis, how ev er, part ic ularly w hen obst ruc t ion is c aused by a mass lesion, MRU met hods may be used t o ident if y t he loc at ion of obst ruc t ion; axial MR imaging met hods f oc used on t his loc at ion t hen should be employ ed t o diagnose t he c ausat iv e lesion.

RENAL FAILURE Alt hough more expensiv e t han sonography and less quant it at iv e t han nuc lear medic ine t ec hniques, CT c an be usef ul in ev aluat ion of nonobst ruc t iv e renal f ailure in general. Alt hough it is nonspec if ic f or diagnosis of t he w ide v ariet y of ac ut e and c hronic parenc hy mal disorders, CT or CT A c an c learly demonst rat e v asc ular c ompromise, part ic ularly renal art erial oc c lusion or st enosis, as w ell as renal v ein t hrombosis. MRI or MRA is similarly ef f ec t iv e f or v asc ular ev aluat ion, part ic ularly in pat ient s w it h c ont raindic at ions t o iodinat ed c ont rast . Alt hough CT c an of t en dist inguish t he f eat ures of ac ut e nonobst ruc t iv e renal f ailure (normal t o sw ollen, nonhy dronephrot ic kidney w it h poor exc ret ion) f rom c hronic (small kidney s w it h dif f use at rophy but no hy dronephrosis) (see F ig. 18- 77), dist inc t ion of t he exac t c ause (e.g., ac ut e t ubular nec rosis v ersus drug- induc ed nephrot oxic it y ) usually is not possible. HIV- assoc iat ed nephropat hy may be suggest ed by nephromegaly and poor exc ret ion in a set t ing of sev ere renal f ailure and nephrot ic sy ndrome (343). In a pat ient w it h no hist ory of preexist ing renal f ailure but rec ent c ont rast exposure, CT demonst rat ion of persist ent high at t enuat ion on unenhanc ed sc ans 24 t o 48 hours lat er is suggest iv e of ac ut e c ont rast nephrot oxic it y , and addit ional c ont rast should be av oided (309) (F ig. 18- 78). Cont rast exc ret ion int o t he gallbladder is of t en also seen in suc h c ases.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2764

18 - The Kidney and Ureter

F igure 18- 77 End- st age renal f ailure. Unenhanc ed CT show s bilat erally at rophied kidney s (ar r ow s) w it h v asc ular c alc if ic at ion and absenc e of c ollec t ing sy st em dilat at ion. Renal sinus f at f ills t he v oid.

F igure 18- 78 Ac ut e t ubular nec rosis w it h abnormally persist ing nephrogram. Unenhanc ed CT show s persist ent c ont rast st aining of t he renal c ort ic es one day af t er prev ious int rav enous c ont rast administ rat ion. Not e t here is no c ont rast w it hin t he aort a (ar r ow ).

P.1282

RENAL TRAUMA T he kidney is t he most c ommonly injured urinary t rac t organ, w it h renal injuries seen in 8% t o 10% of v ic t ims of blunt or penet rat ing t rauma, mot or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2765

18 - The Kidney and Ureter v ehic le ac c ident being t he most f requent (23,362). CT has superseded t he int rav enous urogram and is t he most usef ul imaging t ec hnique f or renal t rauma, as w ell as f or t rauma in general, not only bec ause of it s unsurpassed ac c urac y and det ec t ion of urinary injuries, but also it s abilit y t o ev aluat e mult iple organ sy st ems. T rauma c ommonly af f ec t s mult iple sy st ems, and

t reat ment of t he w hole pat ient w it h early rec ognit ion of all t he injuries is key . T he c urrent t rend is t ow ard non- operat iv e management ; t he abilit y t o ac c urat ely det ec t injuries as w ell as grade t hem w it h CT helps make t his possible. CT is a most ac c urat e imaging t ool t o prov ide a c omprehensiv e ev aluat ion of t he t ot al pat ient , t o st age injuries, and t o prov ide a baseline f or f ollow - up. It c an be most ef f ec t iv e w hen inst alled as c lose t o t he t rauma bay as possible.

Patient selection Alt hough most signif ic ant renal injuries (95%) are assoc iat ed w it h hemat uria, hemat uria has limit ed usef ulness as a selec t ion c rit erion. It is nonspec if ic as t o t he sourc e of bleeding. It may be absent ev en w it h signif ic ant injury , part ic ularly renal inf arc t ion and uret eropelv ic junc t ion disrupt ion (43,480). In addit ion, only about 1 t o 5 in 1,000 pat ient s w it h hemat uria but no hy pot ension af t er t rauma hav e a signif ic ant injury (71,205,370). CT may be selec t ed f or use spec if ic ally t o det ec t GU t rauma in pat ient s w it h gross hemat uria, mic rohemat uria and shoc k, or f indings assoc iat ed w it h renal injury suc h as lumbar f rac t ures. Pat ient s w it h penet rat ing injury and any degree of hemat uria should be imaged. How ev er in prac t ic e, CT is c ommonly perf ormed in pat ient s w it h any abdominal sy mpt oms, hy pot ension, depressed lev el of c onsc iousness, and ev idenc e of high- v eloc it y t rauma w het her hemat uria is present or not .

Imaging Methods Alt hough c onv ent ional radiography remains a st andard segment of t he t rauma ev aluat ion of skelet al injuries, it does not of f er ac c ept able ac c urac y f or det ec t ion of renal injuries. Likew ise, CT has superseded int rav enous urography (IVU). T he IVU has less sensit iv it y and spec if ic it y t han properly perf ormed CT , c an ev aluat e only t he urinary t rac t , ac t ually t akes longer t o perf orm and is dif f ic ult t o perf orm w ell in t he unprepped t rauma pat ient .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2766

18 - The Kidney and Ureter Ult rasound ev aluat ion of t rauma in general is c ont rov ersial and bey ond t he

sc ope of t his t ext . Nev ert heless, solid organ injuries, inc luding renal ones, are c learly more ev ident on CT t han on US (332,333). Alt hough US is sensit iv e t o t he presenc e of int raperit oneal f luid, up t o 65% of renal injuries are not assoc iat ed w it h int raperit oneal f luid, and US is not sensit iv e f or ret roperit oneal f luid. Whereas US may show abnormalit y of t he kidney or perinephric spac e, CT has superior sensit iv it y as w ell as bet t er abilit y t o c lassif y t he sev erit y of injury t o allow f or proper management . T he ac c urac y of CT , inc luding it s abilit y t o show v asc ular injuries and ac t iv e ext rav asat ion, has essent ially eliminat ed t he usef ulness of c at het er angiography in t he ac ut e set t ing, alt hough angiographic t ec hniques remain usef ul f or t reat ment of c omplic at ions suc h as t raumat ic pseudoaneury sm, persist ent ac t iv e bleeding, and hy pert ension. Ret rograde py elography has a v ery limit ed role, alt hough it c an be usef ul t o doc ument uret eral injury bef ore plac ement of a st ent . MRI at present play s no subst ant ial role, largely bec ause of t he dif f ic ult y of it s use in t he emergenc y depart ment set t ing and w it h unst able pat ient s, alt hough it s role may expand in t he f ut ure.

CT Technique Rapid and ac c urat e ev aluat ion of t rauma pat ient s is nec essary , and CT , espec ially mult idet ec t or helic al CT , allow s t his. Ac c urat e diagnoses c an be made w it h axial CT or single det ec t or helic al CT , but MDCT af f ords more rapid imaging, t hus reduc ing t he art if ac t due t o mot ion and breat hing art if ac t . Det ec t ion of injuries suc h as art erial ext rav asat ion is opt imized w it h t he use of MDCT , and it also dec reases t he t ime t he pat ient must remain in t he sc an room. T he more ef f ic ient t ube- heat c apac it y c harac t erist ic of MDCT also allow s f or quic k perf ormanc e of mult iple c onsec ut iv e CT examinat ions (e.g., head, c hest - abdomen- pelv is, spine, and pelv ic bone examinat ions). Ac c ept able ac c urac y in abdominal t rauma CT requires administ rat ion of int rav enous c ont rast , bec ause solid organ and urinary t rac t injuries may be unapparent on unenhanc ed st udies. A usef ul prot oc ol is 120 t o 150 mL low osmolar iodinat ed c ont rast f or adult s (1.5 t o 2.0 mL/kg f or c hildren) w it h pow er injec t or set pref erably at 3 t o 4 mL per sec ond (alt hough 2 mL per sec ond is ac c ept able in t he c ase of limit ed int rav enous ac c ess). Oral c ont rast , alt hough not nec essary f or urinary t rac t injuries, is rout inely used in most t rauma c ent ers, ev en t hough delay f or passage of c ont rast t hrough t he small bow el is not adv isable (141). T o av oid v olume av eraging art if ac t s, image

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2767

18 - The Kidney and Ureter

t hic kness should be 5 mm or less. A pit c h of 1.5:1 on single- slic e helic al CT is ac c ept able; w it h MDCT high speed (pit c h great er t han 1) inc reases image ac quisit ion speed w hile maint aining exc ellent image qualit y . Ret rospec t iv e rec onst ruc t ion of t hinner slic es c an be done (somet imes usef ul f or subt le injuries) if sc ans are perf ormed at less t han maximum t able speed. Kilov olt (peak) of 140 and milliampere sec onds of 100 t o 300 are adequat e, depending on pat ient body size and sc an mode. At present t he aut hors use HS mode on a 4- slic e GE sc anner in t he ED w it h 5 mm images, t able speed 15 mm per sec ond, 0.8- sec ond sc anning w it h delay of 45 sec onds f or c hest , 75 sec onds f or abdomen P.1283 and a pause of 180 sec onds bef ore sc anning t he pelv is. (T he aut hors c urrent ly use 16 в€ћ 1.5 mm det ec t or c ollimat ion, pit c h approximat ely 1:1, and sc an delay of 45 sec onds f or c hest , c ont inuing st raight t hrough abdomen and pelv is in one sc an.) T his does not allow f or bladder f illing; if t here are reasons t o suspec t a bladder injury , f ormal CT c y st ography should be perf ormed (350). T o det ec t or exc lude c ollec t ing- sy st em inv olv ement , delay ed sc ans t hrough t he kidney s may be nec essary . T hese c an be done rout inely (4 t o 8 minut es), but our prac t ic e is t o c hec k t he images w hile pat ient is in t he sc an room and perf orm delay ed images only w hen t here is a renal parenc hy mal abnormalit y , perinephric f luid, or peripelv ic f luid. Uret hral injuries c annot be ac c urat ely assessed w it h CT . Image rev iew is best using a PACS w orkst at ion and sc rolling t hrough images mult iple t imes w it h sof t t issue, bone, and lung w indow set t ings. Alt hough f oc us here is on renal injuries, t he radiologist must ev aluat e all abdominal st ruc t ures w it h t horoughness and at t ent ion t o det ail in t rauma pat ient s.

Classification of Renal Injuries Alt hough t he sc oring sy st em dev ised by t he Americ an Assoc iat ion f or t he Surgery of T rauma (AAST ) w as dev eloped init ially f or researc h purposes, it is of t en used f or c linic al management purposes, bec ause it has been show n t o c orrelat e w it h general sev erit y of injury and w it h perc eiv ed need f or surgic al t reat ment (347). Alt hough it is not st ric t ly based on imaging f eat ures and c lust ers dif f erent imaging pat t erns of injury , it behoov es t he radiologist t o be f amiliar w it h t he language and how it is used in t riage. In t his sy st em, renal injuries are graded ac c ording t o t he dept h of injury as w ell as inv olv ement of v essels and c ollec t ing sy st em:

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2768

18 - The Kidney and Ureter · Grade 1 o Hemat uria w it h normal imaging st udies o Cont usion o Non- expanding subc apsular hemat oma · Grade 2 o Non- expanding perinephric hemat oma c onf ined t o ret roperit oneum

o Superf ic ial c ort ic al lac erat ion less t han 1 c m in dept h w it hout c ollec t ing sy st em injury · Grade 3 o Renal lac erat ion great er t han 1 c m in dept h and does not inv olv e t he c ollec t ing sy st em · Grade 4 o Renal lac erat ion ext ending t hrough t he kidney int o t he c ollec t ing sy st em o Injuries inv olv ing t he main renal art ery or v ein w it h c ont ained hemorrhage o Segment al inf arc t ion w it hout assoc iat ed hemat oma · Grade 5 o Shat t ered kidney o UPJ av ulsion o Complet e lac erat ion, oc c lusion, or t hrombosis of t he main renal art ery or v ein

Grade 1 Injuries Hemat uria w it h normal imaging st udies, renal c ont usion, and small subc apsular hemat omas, eac h c lassif ied as grade 1 injuries, ac c ount f or roughly 80% of kidney injuries. Cont usions on CT are usually seen as poorly marginat ed areas of diminished enhanc ement and exc ret ion. Unlike w it h segment al inf arc t s, t here is some enhanc ement (F ig. 18- 79). A high- at t enuat ion f luid c ollec t ion limit ed bet w een t he surf ac e of t he kidney and t he t rue renal c apsule, not ext ending t hrough t o t he perinephric spac e, is a t y pic al appearanc e of a subc apsular hemat oma (F ig. 18- 80). T hese usually f orm a c resc ent ic shape around only a port ion of t he renal c irc umf erenc e. T hey are less c ommon t han perinephric hemat omas and c an dev elop signif ic ant pressure, result ing in def ormat ion of t he adjac ent kidney ; t his pressure, if great enough, c an result in hy pert ension.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2769

18 - The Kidney and Ureter Grades 2 and 3 Injuries A perinephric hemat oma may be an isolat ed f inding but of t en is seen in c onjunc t ion w it h a renal parenc hy mal lac erat ion. T hus, w hen a perinephric hemat oma is ident if ied, a c aref ul searc h f or an ev en subt ler renal lac erat ion should be made. On CT , perinephric hemat oma appears as an ill- def ined, somew hat high- at t enuat ion c ollec t ion of v ary ing v olume bet w een t he renal surf ac e and Gerot a's f asc ia (F ig. 18- 81). Bec ause t he perinephric spac e is more expandable and t he hemat oma c an t rac k inf eriorly int o t he ret roperit oneal spac e, pressure rarely dev elops t o def orm t he kidney .

An irregular or linear def ec t in t he renal parenc hy ma on c ont rast - enhanc ed CT images is t he hallmark of a renal lac erat ion. T hese may be higher at t enuat ion t han w at er at t enuat ion and do not enhanc e. If t here is no ext rav asat ion f rom t he c ollec t ing sy st em and t he dept h is less t han 1 c m, t he P.1284 lac erat ion is AAST grade 2, and if deeper t han 1 c m, AAST grade 3 (F ig. 1882). T hese injuries are most of t en suc c essf ully managed non- operat iv ely , unless t here is ac t iv e art erial ext rav asat ion, w hic h c an also be managed w it h v asc ular int erv ent ional t ec hniques (52,98,123,267).

F igure 18- 79 Renal c ont usion. In a pat ient w it h rec ent t rauma, a f oc al region of dec reased enhanc ement (ar r ow ) is seen w it hin t he medial aspec t of t he right kidney , w it h a t rac e of perinephric hemat oma (ar r ow head).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2770

18 - The Kidney and Ureter

F igure 18- 80 Subc apsular hemat oma. CT image af t er int rav enous c ont rast show s a c resc ent - shaped hemat oma surround part of t he lef t kidney . T here is dist ort ion of t he renal c ort ex (ar r ow ) at t he post erior aspec t of t he renal margin.

F igure 18- 81 Subc apsular hemat oma. On c ont rast ed CT , a large lef t subc apsular hemat oma c ompresses and dist ort s t he lef t renal c ort ex.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2771

18 - The Kidney and Ureter Perinephric and post erior pararenal spac e hemat omas (ar r ow s) are also present .

F igure 18- 82 Grade 3 renal lac erat ion. On a c ont rast ed CT , a lac erat ion (ar r ow ) ext ends more t han one c ent imet er c ent rally t hrough t he renal c ort ex, and a moderat e perinephric hemat oma is not ed.

Grade 4 Injuries Lac erat ions t hat ext end not only t hrough renal parenc hy ma but also int o eit her t he c ollec t ing sy st em or major v essels are c at egorized as grade 4 and are more signif ic ant injuries. On CT v asc ular ext rav asat ion c an be rec ognized if t here is an abnormal c ollec t ion of c ont rast during t he early parenc hy ma phase bef ore f illing of t he c ollec t ing sy st em has oc c urred. Art erial ext rav asat ion is more c ommon t han v enous ext rav asat ion. If t here is any perinephric or peripelv ic f luid, imaging in exc ret ory phase is needed t o ev aluat e f or ext rav asat ion of opac if ied urine f rom t he c ollec t ing sy st em (F ig. 18- 83). Ev en large amount s of urinary ext rav asat ion of t en resolv e w it h nonoperat iv e management , alt hough st ent plac ement is of t en perf ormed f or t reat ment of injuries w it h moderat e and large urine ext rav asat ions. If v asc ular ext rav asat ion persist s, embolizat ion or surgery may be needed. T hrombosis, dissec t ion or lac erat ion of a segment al art ery c an lead t o a segment al inf arc t ion of parenc hy ma, also a grade 4 injury . T he t y pic al f eat ures on CT are a w ell- delineat ed, linear or w edge- shaped area of c omplet e absenc e of enhanc ement . T here should be neit her bulging nor indent at ion of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2772

18 - The Kidney and Ureter

t he renal c ont our. Segment al inf arc t ions ext end t hrough t he kidney in a radial pat t ern and may be assoc iat ed w it h ot her injuries. T hey may be mult if oc al and may resolv e on f ollow - up examinat ions (F ig. 18- 84), probably as result of c lot ly sis bef ore permanent isc hemic damage, or lead t o residual sc arring (67,70). A possible long- t erm c omplic at ion is hy pert ension (6% t o 20%) (31,56).

Grade 5 Injuries T his c lass inc ludes shat t ered or dev asc ularized kidney s, UPJ av ulsion, and c omplet e lac erat ion or t hrombosis of t he main renal art ery or v ein. Shat t ered kidney (F ig. 18- 85) P.1285 lies at t he ext reme end of t he spec t rum of lac erat ions, w it h mult iple deep lac erat ions c ommonly , w it h c ollec t ing- sy st em ext rav asat ion, and of t en w it h some dev asc ularized regions. Rapid dec elerat ion, suc h as oc c urs w it h highspeed impac t , result s in a hy perext ension t hat c an c ause disrupt ion of t he uret eropelv ic junc t ion (F ig. 18- 86), bec ause t he kidney mov es f orw ard w it h moment um, pulling aw ay f rom t he more f ixed uret er (and/or t he art ery and v ein). An av ulsion of t he UPJ c an be part ial, w hic h is more easily t reat ed w it h a uret eral st ent , or c omplet e. Complet e av ulsion may require early surgic al repair t o salv age an ot herw ise uninjured kidney and av oid c hronic urinoma. F luid medial t o t he pelv is or around proximal uret er suggest s t his injury , and delay ed v iew s may demonst rat e ext rav asat ion (191)(256)(261). T he presenc e of c ont rast in t he dist al uret er (w hic h should alw ay s be searc hed f or in ev ery t rauma CT ) indic at es a part ial disrupt ion. Alt hough a serious injury , hemat uria is of t en minimal or absent (256,261). Caref ul at t ent ion t o det ail w it h know ledge of t he CT f eat ures c an allow f or c orrec t diagnosis and renal salv age; missed diagnosis c an result in c hronic urinoma and ev ent ual nephrec t omy .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2773

18 - The Kidney and Ureter F igure 18- 83 Grade 4 renal t rauma. A: Exc ret ory CT demonst rat es renal lac erat ion w it h assoc iat ed hemat oma. B: Delay ed slight ly more c audal image of t he same CT show s urinary c ont rast ext rav asat ion (ar r ow s) int o t he perinephric spac e and around t he uret er (ar r ow head). A f rac t ured lef t kidney w it h perinephric hemat omas, nev ert heless, show s some parenc hy mal enhanc ement .

F igure 18- 84 Renal Inf arc t . Cont rast ed CT show s absenc e of enhanc ement in t he dorsal aspec t of t he lef t kidney , in a v asc ular dist ribut ion, c onsist ent w it h oc c lusion/disrupt ion of a dorsal branc h of t he lef t renal art ery .

T he st ret c hing of t he elast ic renal art ery in dec elerat ion injury c an result in an inc omplet e v asc ular t ear, w it h result ant t hrombosis of t he main renal art ery , and dev asc ularizat ion of t he kidney . Hemat uria is of t en absent , and bec ause t here is not ac t iv e hemorrhage, t here may not be hy pot ension, unless t he pat ient has ot her injuries (180). T his lesion is readily rec ognizable on c ont rast ed CT , bec ause t he kidney is normal size but show s no enhanc ement ; P.1286 it may be possible t o see c ut of f of t he enhanc ement in t he renal art ery , and absenc e of hemat oma in ret roperit oneum is t y pic al (F ig. 18- 87). T here may be ret rograde f illing of t he renal v ein, and a c ort ic al rim sign may be seen, alt hough more of t en t his is ev ident some t ime af t er t he init ial insult . It is possible t o see ac t iv e ext rav asat ion and massiv e ret roperit oneal hemat oma f rom c omplet e lac erat ion of t he main renal art ery , but pat ient s w it h suc h injuries are unst able and are seen in t he CT suit e only w it h v ery rapid t ransit t o hospit al and sc an room in t he emergenc y depart ment . Renal v asc ular injuries are t he result of v ery - high- energy t rauma and are of t en assoc iat ed w it h ot her sev ere injuries. T his, plus t he poor out c ome of at t empt ed surgic al

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2774

18 - The Kidney and Ureter repair, has led t o t he c urrent prac t ic e at most c ent ers of c onserv at iv e management of art erial t hrombosis. Lat e c omplic at ion of hy pert ension oc c urs in 40% t o 50% of pat ient s managed c onserv at iv ely ; v asc ular int erv ent ion t o inf arc t t he remaining underperf used renal t issue or nephrec t omy may be needed (180,266).

F igure 18- 85 Renal lac erat ion w it h art erial ext rav asat ion. Alt hough no c ont rast exc ret ion has y et oc c urred on t his c ont rast ed CT , ext rav asat ion of densely c ont rast ed blood (ar r ow ) is present medial t o t he renal c ort ex. Mult iple renal lac erat ions are also present .

F igure 18- 86 Post - t raumat ic urinoma. Delay ed CT images af t er c ont rast administ rat ion show s ext rav asat ion of c ont rast - enhanc ed urine f rom t he right c ollec t ing sy st em (ar r ow ), w hic h t rac ks post erior t o t he kidney .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2775

18 - The Kidney and Ureter

F igure 18- 87 Renal art ery av ulsion and inf rac t ed kidney . Exc ret ory phase CT show s non- enhanc ement of t he lef t kidney w it h a t hin rim of c apsular enhanc ement (ar r ow s) sec ondary t o int ac t c apsular art eries. A f oc al injury is present in t he proximal aspec t of t he main renal art ery (ar r ow head).

A serious but muc h less c ommon v asc ular injury is t hrombosis or lac erat ion of t he main renal v ein. A f illing def ec t may be demonst rat ed on CT , or t here may only be non- enhanc ement of t he v ein w it h a delay ed or persist ent nephrogram result ing f rom t he oc c lusion (38,191). A medially loc at ed or c irc umrenal subc apsular or perinephric hemat oma c an result f rom a renal v ein disrupt ion.

Vascular Contrast Extravasation In early - phase c ont rast - enhanc ed CT , images t hat show an area of enhanc ement of similar int ensit y t o t hat of adjac ent v essels in or near an injured kidney represent ac t iv e bleeding, a f inding t hat should be searc hed f or and rec ognized on t rauma CT . If c ont ained, a w ell- c irc umsc ribed area of suc h bright enhanc ement w it hin t he renal parenc hy ma is likely a pseudoaneury sm. Suc h post - t raumat ic pseudoaneury sms may persist and enlarge and c an c ause delay ed bleeding or hy pert ension. Renal lac erat ions c an also c ause art eriov enous f ist ulae, w hic h also c an enlarge and lead t o bleeding, hy pert ension, or high- out put c ardiac f ailure. Ac t iv e f ree hemorrhage is more ill def ined and may hav e a f lame or w at erf all shape, usually w it h assoc iat ed f resh (high- at t enuat ion) hemat oma (F ig. 18-

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2776

18 - The Kidney and Ureter 88). On delay images, t he at t enuat ion remains high but less t han on early images (w hereas leak of c ont rast - enhanc ed urine P.1287

t ends t o c ont inue t o inc rease). As w it h suc h ac t iv e bleeding in ot her areas of t he body , ac t iv e ext rav asat ion f rom renal parenc hy mal or v asc ular lac erat ion may nec essit at e urgent surgery or t ransv asc ular int erv ent ion bec ause exsanguinat ion c an result (239,276,453,552).

F igure 18- 88 Ac t iv e ext rav asat ion. On nephrographic phase CT , a large perinephric hemat oma is present and f oc al art erial ext rav asat ion of c ont rast ed blood is v isible (ar r ow ) in a pat ient w it h a mot or v ehic le t rauma pat ient .

Properly perf ormed t rauma CT , espec ially w it h MDCT loc at ed in t he emergenc y depart ment c lose t o t he t rauma bay , prov ides ac c urat e diagnosis or exc lusion of renal injuries, aiding opt imal, rapid, and ef f ec t iv e t herapy . Alt hough ot her imaging means hav e some pot ent ial role, t he ac c urac y of CT and, in part ic ular, it s abilit y t o st age t he sev erit y of t he injury and det ec t lif e- t hreat ening f indings, suc h as ac t iv e bleeding, giv e CT t he predominant role. Ac c urac y in diagnosis and st aging is key bec ause of t he t rend t ow ard non- operat iv e management . T his is part ic ularly t rue w it h renal injuries; it has been show n t hat ev en w it h v ery sev ere renal injuries, c onserv at iv e, non- operat iv e management in t he long run usually result s in bet t er preserv at ion of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2777

18 - The Kidney and Ureter f unc t ioning renal t issue c ompared w it h early operat ion, w hic h of t en result s in nephrec t omy (52,267).

RENAL VASCULAR DISEASE Art erial phase images may be usef ul t o ev aluat e f or v asc ular anat omy or pat hology and f or surgic al planning. T hey c an be obt ained by using bolus t rac king f eat ures of t he CT sc anner, sequent ial low - dose slic es af t er a small t est injec t ion prior t o t he ac t ual sc an, or a st andard delay of 20 t o 30 sec onds f rom t he beginning of t he c ont rast injec t ion of 75 t o 150 mL of int rav enous c ont rast at 4 t o 5 mL per sec ond. Imaging at approximat ely 20 sec onds helps dec rease any renal v ein opac if ic at ion, w hic h may obsc ure t he art eries w it h st andard maximum int ensit y projec t ion (MIP) images. Wit h v olume rendering or t arget ed region of int erest MIP, t his is less of a problem; t he bet t er opac if ic at ion of t he renal v eins obt ained by sc anning nearer 30 sec onds delay may help in t he det ec t ion of renal v ein anomalies or t umor ext ension. Low - osmolar c ont rast may help dec rease t he c hanc e of nausea and subsequent pat ient mot ion and reduc e t he risk of nephrot oxic it y and of t issue injury if c ont rast ext rav asat ion oc c urs. Images should be obt ained w it h 1- t o 3- mm c ollimat ion, subsec ond sc an t ime, and pit c h of up t o 2:1 t o allow c ov erage of t he area of int erest in a single breat h- hold (c ov erage t ime is no longer a problem on 16+ slic e sc anners). Hy perv ent ilat ion or oxy gen by nasal c annula may be helpf ul t o inc rease breat h- holding t ime w it h single- slic e sc anners. T o improv e st enosis det ec t ion and c harac t erizat ion, as w ell as t he qualit y of of f - axis and 3D rec onst ruc t ions, images should be rec onst ruc t ed w it h 50% ov erlap. Imaging t he kidney s in t he c ort ic omedullary phase of enhanc ement is probably not essent ial f or renal ev aluat ion if images are obt ained in t he nephrographic phase. How ev er, c ort ic omedullary images are of t en obt ained w hen sc an t iming in t he upper abdomen is opt imized f or ev aluat ion of t he liv er f or met ast ases if renal t umor is present or suspec t ed.

Image Review Most diagnoses c an be made f rom rev iew of t he axial image set , but mult iplanar ref ormat t ing may be v ery usef ul f or renal art ery ev aluat ion and surgic al planning. Mult iplanar ref ormat t ed images in t he c oronal or sagit t al planes c an be helpf ul t o bet t er show lesions at t he upper and low er poles and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2778

18 - The Kidney and Ureter w it hin t he c ollec t ing sy st em. Commonly used 3D v isualizat ion t ec hniques inc lude MIP, v olume rendering and oc c asionally shaded surf ac e rendering. MIP images are obt ained by projec t ing v isual “ ray s” t hrough t he v olume of dat a, keeping only t he maximum v alue enc ount ered. MIP images do not show c omplic at ed anat omic relat ionships as w ell bec ause t here is no dept h

inf ormat ion, and t hey do not t y pic ally show int rarenal pat hology w ell. T he MIP t ec hnique does prov ide a more ac c urat e depic t ion of renal art ery st enosis, how ev er (148). Generat ion of MIP images may also require t he edit ing out of unw ant ed high- densit y st ruc t ures suc h as bones, and t his c an of t en be t edious on older w orkst at ions; t heref ore, somet imes limit ed v olume or “ slab” MIP images may be generat ed. Volume rendering has many of t he adv ant ages of bot h surf ac e rendering and MIP. Volume rendering uses t he ent ire v olume of dat a and c an prov ide lif e- like images inc luding c olor, t ransluc enc y or t ransparenc y of dif f erent densit y ranges, and light ing and shading. Measurement of degree of st enosis w it h v olume rendering may be problemat ic , how ev er, bec ause of t he v ariable opac it y of objec t s and dist ort ions of t en int roduc ed t o port ray perspec t iv e. Curv ed planar ref ormat t ed images along t he c ent erline of t he renal art eries are most ac c urat e f or depic t ing t he prec ise degree of st enosis, espec ially w hen t he c ont rast c olumn is part ly obsc ured by c alc ium (148). As w it h all planar imaging, t hey should be c onst ruc t ed in t w o ort hogonal orient at ions t o ac c urat ely port ray st enosis. Ev en if only t he axial images are v iew ed, it is st ill helpf ul t o rev iew a large number of images on a w orkst at ion or CT sc anner t o allow rapid paging t hrough t he images. Sof t c opy rev iew may help t o c ope w it h “ image ov erload,” bec ause a st udy w it h t hin slic es and t hree or more phases c an easily oc c upy more v iew boxes t han many reading rooms hav e. Rev iew ing t he images at a w orkst at ion also av oids t he delay of w ait ing f or t he images t o be f ilmed, pot ent ially speeding pat ient c are. T his paging, or “ c ine,” rev iew c an f ac ilit at e det ec t ion of subt le lesions in t he art eries, renal parenc hy ma, and c ollec t ing sy st em, w here t he anat omic relat ions are c omplex or obliquely orient ed. T he int ense enhanc ement of t he art eries and renal parenc hy ma result ing f rom rapid injec t ion f or t he art erial- phase sc an may c ause t he kidney s and art eries t o be t oo bright and “ burnt out ” f or opt imal v iew ing if f ilmed at st andard w indow and lev el set t ings. Sof t c opy rev iew eliminat es t his problem by allow ing rapid rev iew of opt imized or mult iple w indow and lev el set t ings. P.1288

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2779

18 - The Kidney and Ureter CTA for Renal Artery Stenosis, Renal Artery Stents, and Renal Perfusion Renal art ery st enosis is a c ommon c ause of sec ondary hy pert ension and an import ant and grow ing c ause of renal impairment . Renal art ery st enosis is

generally def ined as great er t han 50% diamet er narrow ing of at least one main renal art ery . Up t o 90% of renal art ery st enosis is f rom at herosc lerot ic v asc ular disease and usually oc c urs in t he ost ial or proximal renal art eries (42). Medial f ibroplasia ac c ount s f or almost all of t he remaining 10% of renal art ery st enosis and usually oc c urs in w omen, t y pic ally y ounger t han 55 y ears of age, w it hin t he dist al t w o t hirds of t he main renal art ery or in branc h renal art eries (42). Medial f ibroplasia, of t en c alled f ibromusc ular dy splasia, is an inf lammat ory v asc ulit is t hat may result in mult iple short st enoses and int erv ening areas of dilat at ion, produc ing a “ beaded” appearanc e of t he renal art ery (42). Diagnosis of renal art ery st enosis is import ant bec ause t reat ment of t he st enosis may result in improv ement in hy pert ension and possible improv ement or st abilizat ion of renal f unc t ion. Imaging modalit ies f or ev aluat ion of renal art ery st enosis inc lude c apt opril nuc lear renal sc an, sonography w it h Doppler, CT angiography , MR angiography , and c at het er angiography . Current ly , t he best sc reening modalit y is st ill c ont rov ersial (42). Bot h c apt opril renal sc an and Doppler ult rasound c an prov ide assessment of t he renal phy siology and t heref ore may be import ant in predic t ing w hic h pat ient s w ill hav e benef it f rom rev asc ularizat ion (42,318,409). Capt opril renal sc an has been demonst rat ed t o hav e a relat iv ely high sensit iv it y and spec if ic it y , bot h about 90%, and is espec ially usef ul in predic t ing improv ement af t er rev asc ularizat ion. Int erpret at ion may be dif f ic ult , how ev er, in pat ient s w it h bilat eral disease, t hose w it h impaired renal f unc t ion, or t hose w it h only one kidney (42,318,409). Sonography is noninv asiv e and c an also prov ide phy siologic inf ormat ion but may be v ery operat or- dependent . Wit h c olor and spec t ral Doppler examinat ion, sonography has been t o show n t o hav e sensit iv it y of up t o 95% and spec if ic it y of 90% (42,486). Dec reased diast olic f low , or elev at ed “ resist iv e index,” demonst rat ed by Doppler ult rasound is also highly predic t iv e t hat hy pert ension w ill f ail t o improv e w it h c orrec t ion of t he st enosis (486).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2780

18 - The Kidney and Ureter Bot h CT angiography and MR angiography c omplement t he phy siologic inf ormat ion prov ided by c apt opril nuc lear sc an and duplex Doppler ult rasound by prov iding noninv asiv e means t o obt ain anat omic inf ormat ion similar t o c at het er angiography (F ig. 18- 89). T hey bot h prov ide more inf ormat ion about ot her renal and ext rarenal abnormalit ies t han does c at het er angiography alone. Early imaging st rat egies hav e been show n t o be more c ost ef f ec t iv e in t he management of renal art ery st enosis (66). MR angiography is espec ially

helpf ul in ev aluat ion of pat ient s w it h poor renal f unc t ion, but it is sensit iv e t o mot ion art if ac t s and has low er spat ial resolut ion t han CT angiography (181,516). Sensit iv it y and spec if ic it y f or signif ic ant renal art ery st enosis w it h single- slic e helic al CT are in t he range of 89% t o 99% and 82% t o 99%, respec t iv ely , c ompared w it h c at het er angiography (148,246). Sensit iv it y w it h c urrent x- ray t ubes and t ec hniques is likely at t he high end of t his range. T he inc reasing av ailabilit y of 16- row and higher MDCT should improv e t he result s ev en f urt her, bec ause ev aluat ion of renal art eries c hallenges t he t ec hnic al limit s of slic e t hinness and c ov erage on single- slic e helic al CT and ev en some early mult islic e sc anners. T he measured spec if ic it y of CT may be f alsely low due t o some f alse–negat iv e angiograms w hen a st enosis at t he origin is obsc ured by t he ov erly ing aort a bec ause of subopt imal obliquit y of t he images (246). One limit at ion of CT angiography is t he limit ed resolut ion f or peripheral st enoses and f ibromusc ular dy splasia (F MD) (246). How ev er, t he spat ial resolut ion of modern mult islic e CT sc anners w it h ample c ov erage lengt h using 0.5- t o 1- mm slic es may be suf f ic ient t o c onsist ent ly det ec t mild or peripheral F MD (F ig. 18- 90) as demonst rat ed on c onv ent ional angiography (186,246). Af t er endov asc ular st ent plac ement f or t he t reat ment of renov asc ular disease, CT angiography may also be a usef ul noninv asiv e t ool t o ev aluat e f or possible rest enosis (26,59,315,414).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2781

18 - The Kidney and Ureter

F igure 18- 89 Bilat eral renal art ery st enosis. Bilat eral renal art ery origin narrow ing (ar r ow s) is w ell show n on obliqued rec onst ruc t ion in a c ephaloc audal orient at ion of art erial phase CT .

Renal Artery Aneurysm Renal art ery aneury sms are unc ommon and of t en not assoc iat ed w it h at herosc lerosis or aort ic aneury sm disease. Most appear due t o medial f ibroplasia (“ f ibromusc ular dy splasia” ), and t hey are more c ommon in w omen. T here is also an assoc iat ion w it h hy pert ension and w it h mult iple pregnanc ies (131,203). Ot her v asc ulit idies, c onnec t iv e t issue disorders suc h as neurof ibromat osis and Ehlers- Danlos, and inf lammat ory proc esses suc h as sept ic emboli and my c ot ic aneury sms are ot her unc ommon c auses. Many are P.1289 now disc ov ered inc ident ally during imaging f or ot her reasons, and most pat ient s are asy mpt omat ic .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2782

18 - The Kidney and Ureter

F igure 18- 90 F ibromusc ular dy splasia w it h renal art ery aneury sm. Art erial phase CT w it h c oronal oblique rec onst ruc t ion show s irregular “ beaded” appearanc e of dist al main renal art ery (ar r ow ). F oc al renal art ery aneury sm is not ed (ar r ow heads).

Indic at ions f or repair v ersus medic al management are st ill not w ell def ined. Renal art ery aneury sms less t han 1.5 c m may saf ely be f ollow ed in most pat ient s (184). Inc reased risk of rupt ure during pregnanc y is a know n risk of renal art ery aneury sm, so expec t at ions f or f ut ure pregnanc y and inc reasing or large size of an aneury sm are f airly w ell est ablished indic at ions f or surgic al t herapy (184). How ev er, improv ement in hy pert ension has more rec ent ly been doc ument ed in pat ient s t reat ed surgic ally c ompared w it h t hose t reat ed medic ally , so surgery may also be indic at ed in pat ient s w it h hy pert ension t hat is dif f ic ult t o c ont rol (203,391,322,415). Renal art ery aneury sms t end t o oc c ur at branc h point s w here t here may be disc ont inuit ies in t he int ernal elast ic lamina, ev en in normal people. Sac c ular aneury sms are t he most c ommon and usually oc c ur at t he f irst or sec ond branc hing of t he main renal art ery in t he renal hilum, but t hey may be w it hin t he renal parenc hy ma; t hey are most ly a result of medial f ibroplasia or at herosc lerosis (see F ig. 18- 90). Mural c alc if ic at ion and mural t hrombus are c ommon, espec ially in larger aneury sms (257,457,524) (F ig. 18- 91). F usif orm aneury sms may oc c ur at any point in t he renal art erial sy st em and are usually a result of medial f ibroplasia (257). Int rarenal aneury sms may also be c aused by poly art erit is nodosa and Wegener granulomat osis or may ac t ually represent pseudoaneury sms.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2783

18 - The Kidney and Ureter Pseudoaneury sms also oc c ur in t he kidney s and may lead t o exsanguinat ing hemat uria or perinephric hemat oma, or t hey may c ause or be sec ondary t o art eriov enous f ist ula. T hey may be sec ondary t o penet rat ing or blunt t rauma or iat rogenic injury during int rav asc ular proc edures or may oc c ur f ollow ing renal or renov asc ular surgery . Inf lammat ory proc esses and t umors also somet imes result in int rarenal pseudoaneury sms. Int rarenal loc at ion of aneury sm and c linic al inf ormat ion should suggest t he diagnosis of renal pseudoaneury sm. Hist oric ally pseudoaneury sms hav e been ev aluat ed w it h c at het er angiography , but art erial or early v enous- phase CT may also rev eal t hem and allow f or c harac t erizat ion of assoc iat ed renal abnormalit ies (346).

F igure 18- 91 Sac c ular renal art ery aneury sm. Coronal obliqued v olume rec onst ruc t ion image of CT angiography demonst rat es a sac c ular lef t renal art ery aneury sm (ar r ow ) in a middle- aged w oman.

Vasculitis In addit ion t o st enoses and aneury sms, small v essel v asc ulit is assoc iat ed w it h diseases suc h as poly art erit is nodosa, Wegener granulomat osis, and sy st emic lupus ery t hemat osis may c ause abnormalit ies of renal perf usion at t he subsegment al lev el, result ing in a st riat ed nephrogram or f rank inf arc t ions

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2784

18 - The Kidney and Ureter

leading t o sc ars (F ig. 18- 92). Poly art erit is nodosa and Wegener granulomat osis may also be a c ause of P.1290 spont aneous perinephric hemorrhage (114). Pat ient s w it h sy st emic lupus ery t hemat osis may hav e enlarged kidney s during t he ac ut e phase or diminished renal size lat er in t he disease. T hey may hav e art erial f indings similar t o t hose of ot her small v essel v asc ulit idies but are also at v ery high risk f or renal v ein t hrombosis, w hic h may oc c ur in up t o one t hird of pat ient s w it h SLE and nephrot ic sy ndrome (51,464).

F igure 18- 92 Vasc ulit is. Cont rast enhanc ed CT show s bilat eral st riat ions inv olv ing t he renal c ort ic es. T his appearanc e resembles py elonephrit is, but no perinephric st randing is present . T he c linic al present at ion w as not c onsist ent w it h ac ut e py elonephrit is.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2785

18 - The Kidney and Ureter F igure 18- 93 Art eriov enous malf ormat ion. A: Cont rast ed CT show s early

f illing of a dilat ed renal v ein (ar r ow ). B: On a slight ly c audal image, a bright ly enhanc ing c ent ral renal lesion is present .

Arteriovenous Communications Direc t c ommunic at ion bet w een art eries and v eins may be v isible on CT and MRI examinat ions of t he kidney s. T hey are most c ommonly iat rogenic , suc h as f rom renal biopsy or blunt or penet rat ing t rauma in t he f orm of art eriov enous f ist ula (AVF ), and are of t en asy mpt omat ic and usually spont aneously resolv e. T hey may somet imes present w it h c ongest iv e heart f ailure or a f lank bruit if t here is v ery high f low . AVF s may c ause persist ent or delay ed hemat uria and rarely may result in hy pert ension, t hought t o result f rom segment al isc hemia peripheral t o t he AVF (99,176,221,257). AVF s may also oc c ur bec ause of inf lammat ory proc esses, t umors, or adjac ent aneury sms eroding int o a v ein. T here is t y pic ally a single dilat ed f eeding art ery and a single v ery dilat ed draining v ein. Direc t c ommunic at ion bet w een t he renal art eries and v eins w it hout an int erv ening c apillary bed may rarely oc c ur spont aneously in t he f orm of art eriov enous malf ormat ions (AVM). T hese t y pic ally inv olv e mult iple small c onnec t ions bet w een t he art ery and v ein and may present w it h gross hemat uria if loc at ed adjac ent t o t he c ollec t ing sy st em or w it h subc apsular or perinephric hemat oma if t here is c ort ic al inv olv ement (99,221,257). CT and MRI during early phases of c ont rast c an show t he dilat ed v asc ular st ruc t ures (F ig. 18- 93) as w ell as early enhanc ement of t he inf erior v ena c av a and ipsilat eral renal v ein.

Renal Artery Dissection Dissec t ion of t he renal art ery and it s branc hes may result in st enosis, aneury smal dilat at ion, or bot h. Dissec t ion may be sec ondary t o blunt t rauma, art erial c at het erizat ion, ext ension of aort ic dissec t ion or result f rom primary renal art ery pat hology suc h as at herosc lerosis or int imal or perimedial f ibroplasias (257,354,470). CT w it h t hin sec t ions may show t he int imal f lap or aneury sm and any assoc iat ed perf usion abnormalit ies or inf arc t ions. Dissec t ion w it h impaired renal f low may c ause impaired renal f unc t ion or sec ondary hy pert ension, and t hese are generally c onsidered indic at ions f or rev asc ularizat ion. Aneury sms sec ondary t o dissec t ion are generally c onsidered unst able and are repaired (354,391,470).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2786

18 - The Kidney and Ureter Renal Vein Thrombosis

Renal v ein t hrombosis is an unc ommon v asc ular pat hology t hat may be a c ause of renal dy sf unc t ion and may also present w it h f lank pain and hemat uria. Renal v ein t hrombosis is usually assoc iat ed w it h hy perc oagulable st at es, renal disease, or bot h (304,555). It most c ommonly oc c urs in pat ient s w it h nephrot ic sy ndrome, espec ially t hat P.1291 c aused by membranous glomerulonephrit is (304), and in pat ient s w it h lupus, w ho may hav e bot h nephrit is and a hy perc oagulable st at e (51,464). Renal c ell c arc inoma has a predilec t ion f or direc t ext ension int o t he renal v ein and v ena c av a and t ransit ional c ell c arc inoma may also more rarely c ause t umor t hrombus (72,458,524). In c hildren, renal v ein t hrombus oc c urs sec ondary t o dehy drat ion in inf ant s and f rom ext ension of Wilms t umor (257). T rauma t o t he kidney or renal hilum may c ause disrupt ion or t hrombosis of t he renal v ein and oc c urs in all age groups. Ext ension of IVC or lef t ov arian v ein t hrombus may rarely c ause sec ondary t hrombosis of t he renal v ein (257). Ult rasound and MRI w it h MRV are pref erred imaging t ec hniques if t here is renal dy sf unc t ion. CT w it h int rav enous c ont rast may be used if t here is not subst ant ial renal dy sf unc t ion. Renal v ein t hrombus may be seen sec ondarily on CT perf ormed primarily f or ev aluat ion of hemat uria, hy perc oagulable st at e, renal t umors, or t rauma. Renal v ein t hrombus inv olv es t he lef t renal v ein slight ly more of t en t han t he right , possibly bec ause of t he longer c ourse of t he lef t renal v ein (257). Ac ut e renal v ein t hrombus present s w it h an expanded, non- enhanc ing, or only peripherally enhanc ing, t hic k w alled v ein, t y pic ally w it h edema around t he v ein and kidney (168). T umor t hrombus may show enhanc ement , somet imes w it h early enhanc ement of t umor art eries w it hin t he renal v ein t umor. T here may be renal enlargement of and poor or no exc ret ion (168). Ult rasound show s dec reased or rev ersed diast olic art erial f low and absent or diminished v enous f low . Chronic renal v ein t hrombosis demonst rat es at t enuat ion of t he renal v ein and enlarged c ollat eral v eins around t he renal hilum and upper uret er (257,510).

Nutcracker Syndrome

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2787

18 - The Kidney and Ureter

In pat ient s w it h “ nut c rac ker sy ndrome” t he lef t renal v ein is c ompressed bet w een t he aort a and an abnormally st eeply angled originat ion of t he superior mesent eric art ery . T he result ant lef t renal v ein hy pert ension leads t o t he dev elopment of v aric es around t he renal hilum and proximal uret er (118,217). Sev ere pain or rec urrent gross hemat uria may require int erv ent ion, usually by renal v ein t ransposit ion t o low er on t he inf erior v ena c av a (215), or more rec ent ly renal v ein st ent plac ement (107,447,546). In pat ient s w it h nut c rac ker sy ndrome, sev ere narrow ing of t he renal v ein c rossing t he aort a and dilat at ion of t he v ein proximal t o t his or obv ious v aric es around t he renal hilum or upper uret er may be demonst rat ed by CT , MRI, or ult rasound. T hin- sec t ion CT w it h sagit t al and c oronal ref ormat ed images or MR angiography w it h sagit t al images may be helpf ul in demonst rat ing an abnormally st eep originat ion of t he superior mesent eric art ery (463). Pressure gradient may need t o be measured in t he renal v ein direc t ly in equiv oc al c ases, but t here is ov erlap w it h normal range (up t o 10 c m w at er) (217).

Computed Tomography Angiography for Surgical Planning for Tumors CT is w idely used in t he det ec t ion and st aging of renal masses. When a radic al nephrec t omy is planned f or renal c ell c arc inoma, delineat ion of t he det ailed renal art ery anat omy may not be nec essary ; how ev er, segment al nephrec t omy is an inc reasingly used opt ion f or small c arc inomas or indet erminat e t umors t hat may be benign and f or loc alized renal t umors w here t here is a need f or a nephron- sparing proc edure. Radic al and segment al nephrec t omy c an eac h be perf ormed laparosc opic ally in appropriat e pat ient s (165). Indic at ions f or nephron- sparing surgery inc lude t umors arising in a single kidney , renal dy sf unc t ion, mult iple sy nc hronous t umors, abnormalit y of t he c ont ralat eral kidney , or heredit ary c ondit ions suc h as v on Hippel- Lindau disease (373). In preoperat iv e management , CT w it h CT angiography allow s t he surgic al approac h t o be planned using inf ormat ion on t he relat ionship of t he kidney and lesion t o t he ribs, iliac c rest and spine, renal v asc ulat ure, renal margins, and c ollec t ing sy st em (94). T hin- slic e CT w it h mult idet ec t or- row CT may also allow f or bet t er ev aluat ion of ev en minimal inv asion of t he perirenal f at , an import ant sign indic at ing t hat nephron- sparing surgery may not be possible

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2788

18 - The Kidney and Ureter (72). Volume- rendering t ec hniques are espec ially usef ul in present ing t his c omplex dat a f or surgic al planning and c an show t he images in a “ surgic al orient at ion” (F ig. 18- 94) and allow int erac t iv e or v ideot aped progressiv e

remov al of lay ers t o depic t t he key anat omic relat ionships f or surgic al planning (94,458,564).

F igure 18- 94 Assist anc e f or surgic al planning. Volume rec onst ruc t ion of CT art eriogram is f urt her annot at ed w it h c olor in t he region of a f oc al c ort ic al mass prior t o nephron sparing surgery . T he st udy show s t he relat ion of t he t umor (ar r ow ) t o t he adjac ent ribs.

P.1292

UPJ Obstruction CT w it h CT angiography is also usef ul f or t he ident if ic at ion of pot ent ial c omplic at ions during t he repair of UPJ obst ruc t ion. In t he c urrent t reat ment of UPJ obst ruc t ion, perc ut aneous or uret erosc opic t herapy has bec ome a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2789

18 - The Kidney and Ureter

st andard opt ion t hat av oids an open surgery . How ev er, up t o 40% of pat ient s may hav e a c rossing ac c essory art ery t hat may be relat ed t o t he UPJ obst ruc t ion and inc rease t he likelihood of c omplic at ion f rom hemorrhage as w ell as inc rease t he f ailure rat e of endosc opic t herapy (527). Most of t he c rossing v essels are ant erior t o t he UPJ, so t he proc edure inv olv es a c ut in t he uret eropelv ic junc t ion in t he post erior- lat eral direc t ion. Signif ic ant numbers of c rossing v essels are post erior (345), how ev er, and some surgeons adv oc at e rout ine ev aluat ion of pat ient s f or c rossing v essels preoperat iv ely w it h c at het er or CT angiography . Espec ially if t here is kinking at t he UPJ, an open or laparosc opic proc edure is perf ormed f or pat ient s w it h c rossing v essels (382,521). Renal CT w it h CT angiography allow s depic t ion of any c rossing v essels in t he pot ent ial inc ision sit e prior t o endosc opic surgery and show s t he ant erior or post erior relat ionship of t he art ery t o t he UPJ t hat is not show n w it h c at het er angiography (F ig. 18- 95), if pat ient s are st ill c onsidered f or endosc opic surgery (262,345,408,430,466,479,521).

Computed Tomography and Computed Tomographic Angiography for Renal Donors T radit ional ev aluat ion of pot ent ial renal donors has inc luded int rav enous py elography (IVP) and c at het er angiography . CT w it h CT angiography is supplant ing bot h t he IVP and c at het er angiogram in many inst it ut ions and allow s f or a single, noninv asiv e out pat ient proc edure.

F igure 18- 95 Crossing v essel. A: CT art eriogram show s dilat at ion of t he lef t renal pelv is and c aly c es. B: On slight ly c audal image, a c rossing v essel

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2790

18 - The Kidney and Ureter (ar r ow ) is present . T here is a high assoc iat ion of c rossing v essel w it h

uret eropelv ic junc t ion obst ruc t ion. Not e t he st udy w as perf ormed t o ev aluat e t he aort ic aneury sm (ar r ow head).

F indings t hat af f ec t t he t ransplant proc edure inc lude ac c essory renal art eries, early renal art ery branc hing, f ibromusc ular dy splasia, renal v enous anomalies, and duplic at ed c ollec t ing sy st ems. Alt hough many of t hese v ariant s may st ill allow t ransplant at ion, t heir presenc e may c omplic at e t he surgery or f av or selec t ion of t he c ont ralat eral kidney f or donat ion. Ot her f indings suc h as nephrolit hiasis, renal ec t opia, renov asc ular disease, renal asy mmet ry , numerous renal art eries, renal t umor, or ext rarenal abnormalit ies may ev en prec lude donat ion (373,471). Laparosc opy has more rec ent ly been used f or harv est ing t ransplant kidney s and reduc es t he risk, disc omf ort , and rec ov ery t ime of donors w hen c ompared w it h open nephrec t omy . How ev er, t he v isualizat ion of adjac ent v asc ular st ruc t ures at surgery may be more rest ric t ed during laparosc opic nephrec t omy . Venous anat omic v ariant s c an hav e serious c onsequenc es and may result in hemorrhage or c onv ersion t o an open proc edure (373,471). Compared w it h c at het er angiography , CT angiography has a sensit iv it y of 95% t o 100% and spec if ic it y 99% t o 100% f or ac c essory renal art ery det ec t ion and sensit iv it y 93% t o 100% and spec if ic it y 99% t o 100% f or prehilar branc hes (120,148,253,258,263,400,471). Most st udies also show at least some ac c essory art eries t hat are bet t er seen w it h CT , and t hey suggest t hat v enous and renal parenc hy mal abnormalit ies are bet t er seen w it h CT (109,252,400,434,471) (F igs. 18- 96, 18- 97, and 18- 98). Ev en f or c ent ers t hat do not perf orm renal donor ev aluat ion, t his researc h demonst rat es t he abilit y of CT angiography t o ac c urat ely depic t renal art erial abnormalit ies and t iny ac c essory art eries.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2791

18 - The Kidney and Ureter

F igure 18- 96 Renal donor CT art eriogram. T w o right renal art eries are present in a pat ient being ev aluat ed f or renal donat ion.

P.1293

RENAL SURGERY Renal Biopsy T he use of minimally inv asiv e t ec hniques in radiology has inc reased in t he urinary sy st em. Alt hough surgery is t he c urrent t herapy f or most primary renal neoplasms, biopsy of renal disease is a saf e, ac c urat e met hod t hat c an help in c ert ain c linic al sit uat ions (550,557). Biopsy may be usef ul if t he pat ient is a poor surgic al c andidat e and loc alized perc ut aneous t herapy is av ailable. It may help t o prev ent surgery if met ast asis is c linic ally suspec t ed. Preoperat iv e diagnosis of at y pic al renal hist opat hologies may guide nonsurgic al t herapy . Considerat ions during renal biopsy should inc lude t he pot ent ial t o af f ec t subsequent t herapy , pot ent ial f or inadequat e spec imen, and pot ent ial c omplic at ions. Homogeneous mult iple renal masses may raise t he quest ion of renal ly mphoma. In renal ly mphoma, surgery may not be t he pref erred met hod of t reat ment , and biopsy c an be espec ially helpf ul. Perc ut aneous biopsy has sensit iv it y of 90% and negat iv e predic t iv e v alue of 64%. How ev er, in small or v ery large masses, t he negat iv e predic t iv e v alue is low (439). Insuf f ic ient

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2792

18 - The Kidney and Ureter t issue is t he most c ommon c ause f or f alse–negat iv e result s (557). F or CT guided biopsies, t he ac c urac y w as similar in all lesions, regardless of size (134). T he ac c urac y of CT - guided c ore biopsy f or t umor t y pe is 90%, but it w as less ac c urat e f or grading of t umors (282,366). F or t he diagnosis of malignanc y , ult rasound- guided c ore biopsy is ext remely ac c urat e (63). In

indet erminat e c y st ic renal lesions, t here is inc reased likelihood of an inc orrec t diagnosis by imaging- guided biopsy w it h sensit iv it y f or malignanc y 71% (279). CT - guided biopsy may also be helpf ul t o ev aluat e borderline enlarged ly mph nodes in t he ret roperit oneum bef ore nephrec t omy (F ig. 18- 99).

F igure 18- 97 Ret roaort ic lef t renal v ein. On CT angiography c oronal rec onst ruc t ion f or ev aluat ion of renal donor, a ret roaort ic lef t renal v ein (ar r ow ) c ourses c audally t o t he normal renal v ein loc at ion. T his is import ant in surgic al planning.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2793

18 - The Kidney and Ureter

F igure 18- 98 Venous v ariant . A large lumbar v ein (ar r ow ) drains int o t he lef t renal v ein on t his c oronal rec onst ruc t ion of a renal donor CT art eriogram. Alt hough t he image appears as if t he v ein is ret roaort ic , t his is art if ac t ual due t o t he maximum int ensit y projec t ion t ec hnique.

As t he number of inc ident al renal masses c ont inues t o inc rease, ef f ort s are being made t o reduc e t he oc c urrenc e of P.1294 nephrec t omy f or benign lesion. Perc ut aneous biopsy of a renal mass is more c ommonly being perf ormed in t hese c ases. T he diagnosis c an be det ermined in 72% of t hese pat ient s, but many are insuf f ic ient f or def init iv e diagnosis (420). T he inc idenc e of seeding f rom a low pot ent ial t umor is v ery low , but has been doc ument ed (121,468,566). How ev er, t he risk may be reduc ed w it h t he use of c ut t ing needles (282). T he likelihood of t rac t seeding is higher f or biopsy of T CC, and biopsy should be av oided in t hese pat ient s (209,468).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2794

18 - The Kidney and Ureter

F igure 18- 99 Perc ut aneous biopsy . Prone CT guided biopsy is perf ormed w it h v isualizat ion of t he needle t ip in a hilar nodal mass (n) in a pat ient w it h renal c ell c arc inoma.

Biopsy f or dif f erent iat ion of met ast at ic disease f rom a c onc urrent RCC in a pat ient w it h a malignanc y may also help guide t herapy . In one series w it h know n ext rarenal malignanc ies, biopsy of solid renal masses f ound sy nc hronous RCC more of t en t han met ast asis (439). If RCC is c onf irmed, surgic al t herapy or radiof requenc y ablat ion may be perf ormed. How ev er, if t he lesion is diagnosed as a met ast at ic lesion, sy st emic t herapy may be indic at ed rat her t han surgery . Pat ient s ref erred f or renal biopsy should be ev aluat ed f or bleeding risk f ac t ors or c oagulat ion dy sf unc t ion. At our inst it ut ion, w e t y pic ally pref er an INR of 1.3 or less f or c ore biopsy . T he lev el of plat elet s should be at least 60,000, but 100,000 is pref erred. Hemoglobin and hemat oc rit lev els should be know n bef ore t he proc edure so t hat t he pat ient may be f ollow ed if hemorrhage is suspec t ed. Commonly , t w o t o f iv e biopsies are perf ormed w it h guidanc e (63). CT appearanc e af t er biopsy may c ommonly demonst rat e moderat e at t enuat ion subc apsular hemat oma (F ig. 18- 100) or hemorrhage in t he perinephric spac e (282). Post biopsy imaging does not usually inc lude int rav enous c ont rast unless t here is high suspic ion of ac t iv e ext rav asat ion. How ev er, if t here is signif ic ant hemat oc rit drop in t he hours af t er biopsy , repeat CT is perf ormed and c ont rast c an be used if ac t iv e ext rav asat ion is suspec t ed.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2795

18 - The Kidney and Ureter MRI is sensit iv e f or hemorrhage af t er biopsy . T he heme produc t s are usually det ec t able by a c ombinat ion of T 1 and T 2 sequenc es. T he signal

c harac t erist ic s w ill depend on t he t ime of imaging relat iv e t o t he hemorrhage.

F igure 18- 100 Complic at ion of renal biopsy . Unc ont rast ed CT af t er renal biopsy demonst rat es dense hemat oma in t he lef t renal parenc hy ma (ar r ow s) w it h assoc iat ed perinephric hemat oma. Hemat omas are c ommon af t er renal biopsy .

Renal biopsy is assoc iat ed w it h sev eral pot ent ial c omplic at ions (170). T he most c ommon c omplic at ion af t er biopsy is loc alized hemorrhage in t he ret roperit oneal spac e, as high as 17% using a 14- gauge biopsy gun needle (402). Small perinephric hemat oma is c ommon af t er a biopsy but does not require f urt her t herapy unless t he hemat oma is large or t here is dec ompensat ion of t he pat ient bec ause of blood loss. T he inc idenc e of sev ere hemorrhage is less t han 3% f or 18- gauge biopsy and less t han 4% f or 14gauge biopsy (475). T he risk of major c omplic at ion is low er in biopsy of a t ransplant ed kidney allograf t , approximat ely 1% (41). Ev en f or large ret roperit oneal hemorrhage, ac t iv e bleeding usually subsides ow ing t o t amponade ef f ec t by t he hemat oma in t he c onf ined spac e. How ev er, if t here is int raperit oneal ext ension of t he hemorrhage, surgery is indic at ed bec ause t he hemorrhage w ill not likely t amponade. Anot her possible c omplic at ion of renal biopsy is art erial v enous f ist ula f ormat ion. T he c omplic at ion is not t y pic ally v isible at t he t ime of biopsy or on immediat e f ollow - up. How ev er, on subsequent examinat ions, an art erial v enous c ommunic at ion is of t en v isible af t er prior renal biopsy . T he f indings on CT

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2796

18 - The Kidney and Ureter inc lude an abnormal early enhanc ement of t he renal v ein, w hic h appears dilat ed relat iv e t o t he ot her renal v ein. T here may be early c ont rast

opac if ic at ion of t he IVC. T he renal art ery may be dilat ed. Rarely , an AVM may be exophy t ic t o t he renal parenc hy ma. Ot her c omplic at ions of biopsy inc lude inf ec t ion or nont arget organ injury . T he rat e of inf ec t ion is low bec ause of t he high v asc ularit y of t he kidney , but it may oc c ur. Renal absc ess or py elonephrit is c an usually be t reat ed w it h P.1295 medic al t herapy using ant ibiot ic s. T he most sev ere of c omplic at ions in t he adjac ent organs f or CT - guided renal biopsy is perf orat ion of t he c olon. Whereas small bow el perf orat ion t y pic ally heals, t here is repeat ed dist ent ion of t he c olon in t he phy siologic st at e and t he pat ient may require surgic al c orrec t ion if t here is c olonic perf orat ion. Ot her organs adjac ent t o t he kidney s t hat may be injured during biopsy are t he liv er, spleen, panc reas, and aort a as w ell as t he inf erior v ena c av a. How ev er, t he rat e of nont arget c omplic at ion is low .

Renal Transplant Preoperative Evaluation: Recipient Pat ient s w it h c hronic renal f ailure are c ommonly ev aluat ed f or renal t ransplant at ion. Renal t ransplant at ion has been show n t o be t he most ef f ec t iv e t reat ment of c hronic renal f ailure w it h t he great est suc c ess in t he long t erm. Bec ause of t he high c ost and c omplexit y of t he surgery , as w ell as t he short age of adequat e donor kidney s, a rigorous ev aluat ion is perf ormed in t he pot ent ial t ransplant rec ipient prior t o surgery . T he rec ipient w ill be c hronic ally t reat ed w it h immunosuppression; t heref ore, t he presenc e of a t umor must be exc luded bef ore t he surgery , bec ause immunosuppression may allow a low - grade t umor t o w orsen or met ast asize. In pat ient s w it h poly c y st ic kidney disease, t he nat iv e kidney s may be espec ially large and may limit t he amount of spac e in t he perit oneum. In some c ases, a nat iv e kidney may be surgic ally remov ed at t he t ime of t ransplant at ion surgery . T here may be some residual impac t of t he poly c y st ic kidney s on c reat inine c learanc e and f luid balanc e, so bilat eral nephrec t omy is not perf ormed w it hout c onsiderat ion. At our inst it ut ion, t here is a large hemodialy sis populat ion. As pat ient s remain on hemodialy sis f or longer t imes, t here is inc reased v asc ular c alc if ic at ion of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2797

18 - The Kidney and Ureter t he art erial sy st em (456). T here hav e been sev eral c ases in w hic h t he iliac art eries w ere sev erely c alc if ied t o t he ext ent t hat t he abilit y of t he surgeon t o plac e a t ransplant kidney w as sev erely limit ed. T here hav e been c ases w here t he t ransplant allograf t w as lost bec ause of t his problem (10). In one series f rom Spain, approximat ely 29% of c hronic dialy sis pat ient s had sev ere iliac c alc if ic at ions t hat w ould limit t ransplant anast omosis f ormat ion (10). Pat ient s ev aluat ed t o possibly rec eiv e a t ransplant kidney are rout inely

ev aluat ed w it h abdominal radiography f or pelv is c alc if ic at ions. In pat ient s w it h minimal or no c alc if ic at ions, no f urt her ev aluat ions are perf ormed of t he art eries. How ev er, if t here are moderat e or sev ere iliac c alc if ic at ions, a CT examinat ion is perf ormed t o c harac t erize t he ext ent of c alc if ic at ions. Our surgeons require a 3- c m region of t he ext ernal iliac art eries t hat is essent ially f ree of c alc if ic at ions f or plac ement of t he allograf t . In some sit uat ions, t he t ransplant may be perf ormed despit e t he presenc e of small c alc if ic at ions in t his region. T o c losely ev aluat e t hese pat ient s w it h moderat e t o sev ere c alc if ic at ions, pelv is CT is perf ormed w it h c ont iguous 5- mm- t hic k slic es w it hout int rav enous or oral c ont rast . T he radiology report should det ail t he ext ent of pelv is c alc if ic at ions as w ell as desc ribe any inc ident al f indings.

Renal Transplant Preoperative Evaluation: Donor T he renal donor is ev aluat ed espec ially c losely bef ore donat ion of a kidney . Comprehensiv e t est ing is perf ormed t o minimize t he risk t hat a pat ient w it h int rinsic renal disease or pot ent ial f or f ut ure renal f ailure donat es a kidney . T he t radit ional met hod of ev aluat ion of t hese pat ient s has inc luded IVU, nuc lear renal sc an, and c onv ent ional angiography . More rec ent ly , mult iphase CT w it h CT urography has been perf ormed in lieu of IVU and angiography . Prec ont rast images are init ially obt ained t o exc lude urinary c alc ulus. T he prec ont rast images also allow f or loc alizat ion of t he kidney s bef ore CT and CT angiography . Using rapid int rav enous c ont rast bolus, CT angiography w it h t hin slic es is perf ormed and 3D v olumet ric rec onst ruc t ion images are obt ained t o simulat e t he f indings of c onv ent ional angiography . Port al v enous phase images are subsequent ly perf ormed t o det ec t any small renal t umors or urinary abnormalit ies prior t o surgery . At our inst it ut ion, a CT urogram is immediat ely obt ained af t er t he CT t o c harac t erize t he appearanc e and number of uret ers. T he sensit iv it y of CT f or renal c alc ulus is higher t han has been prev iously det ec t able on IVP. CT is also more spec if ic f or c harac t erizing a f oc al renal abnormalit y . In f ac t , most abnormal IVP f indings in renal donors are not

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2798

18 - The Kidney and Ureter malignant , but require f urt her st udy . T hese pat ient s are t y pic ally ev aluat ed w it h CT bef ore f urt her c onsiderat ion f or t ransplant at ion. Early det ec t ion of c alc uli in t he ev aluat ion proc ess may prev ent t he pot ent ial donor f rom

undergoing f urt her, more inv asiv e t est ing. T he purpose of CT angiography is t o c harac t erize t he loc at ion and number of renal art eries. Approximat ely 30% of pat ient s hav e mult iple renal art eries in at least one kidney (90). T he lef t kidney is generally pref erred f or t ransplant at ion, if all else is equal, bec ause of t he longer lef t renal v ein. How ev er, if t here are mult iple lef t renal art eries and a solit ary right renal art ery , t he right kidney may be t aken. T he presenc e of mult iple uret ers on t he lef t is also a pot ent ial indic at ion f or donat ion of t he right kidney . If t here is a f oc al c y st or pot ent ial renal lesion in t he right kidney , t he abnormal kidney w ill be resec t ed and ev aluat ed, and if t he lesion is benign, t he kidney w ill be plac ed in t he t ransplant rec ipient . An ov erriding princ iple in renal t ransplant donat ion is t hat t he renal donor ret ains t he kidney t hat has t he best pot ent ial f or f unc t ion if t he kidney s are possible t o resec t . MRI may be used t o ev aluat e pat ient s in a similar w ay t o CT . T he sensit iv it y f or c alc if ic at ions is less t han t hat of CT , and MRI is more sensit iv e t o mot ion art if ac t degrading t he st udy . MR angiography is perf ormed during t he art erial phase. P.1296 T 2- w eight ed images, prec ont rast T 1- w eight ed images, and mult iphase c ont rast ed T 1- w eight ed images should be used w it h int rav enous injec t ion of gadolinium c ont rast .

Renal Transplant Postoperative Evaluation and Acute Complications A pat ient rec eiv ing a t ransplant kidney undergoes a c omplex proc edure in w hic h t he renal art ery and renal v ein are anast omosed t o t heir respec t iv e v essels in t he iliac region. T he t ransplant uret er is anast omosed t o t he urinary bladder f or drainage of urine. T he surgic al proc edure may t ake sev eral hours, and t here is pot ent ial f or sev eral c omplic at ions. In liv ing relat ed donor donat ion, c omplic at ions oc c ur in approximat ely 16% of pat ient s, and many of t hese c an be det ec t ed by CT (269). T ransplant renal art ery st enosis (F ig. 18- 101), a c ommon problem in renal t ransplant s (136), may result in sev ere impairment of renal perf usion, c ausing

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2799

18 - The Kidney and Ureter allograf t dy sf unc t ion. T he most sev ere of all c omplic at ions is renal art ery t hrombosis w it h loss of t he t ransplant kidney . T his is ext remely rare, but it is dev ast at ing and is best imaged by ult rasound in t he emergent set t ing (525). In renal art erial t hrombosis, t he kidney may demonst rat e a c omplet e or segment al lac k of enhanc ement on c ont rast ed CT . Renal v ein t hrombosis (F ig. 18- 102) is also a sev ere c omplic at ion in t he t ransplant ed kidney . Post surgic al art eriov enous f ist ula is anot her pot ent ial c omplic at ion, oc c urring in 10% t o 15% of biopsy f ollow - up st udies (337,341).

In f ac t , f ist ulae in t he t ransplant kidney s are muc h more c ommon t han f ist ulae in t he nat iv e kidney s. Ot her c omplic at ions of renal t ransplant at ion inc lude ac ut e t ubular nec rosis or ac ut e rejec t ion. In t hese c ases, t he t ransplant kidney s may be pat c hy in appearanc e and may show reduc ed c onc ent rat ion of int rav enous c ont rast . T y pic ally an elev at ed c reat inine in t hese pat ient s w ill prec lude c ont rast CT unt il t he c reat inine has been reduc ed. In t hese pat ient s, ult rasound or MRI is usually pref erred as t he init ial f orm of imaging.

F igure 18- 101 T ransplant renal art ery st enosis. A: In a pat ient w it h t ransplant dy sf unc t ion, v olume rec onst ruc t ion of t he t ransplant ed kidney show s t ransplant renal art ery narrow ing (ar r ow ). B: Spec t ral Doppler ult rasound has elev at ed peak sy st olic v eloc it y , also c onsist ent w it h t he diagnosis.

Transplant Postoperative Chronic Complications In a pat ient w it h a renal t ransplant , monit oring f or ot her long- t erm c omplic at ions should be perf ormed. Hy dronephrosis, hy drouret er, renal art erial disease, and c hronic rejec t ion may all oc c ur in a t ransplant ed kidney .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2800

18 - The Kidney and Ureter Hy dronephrosis result ing f rom urinary obst ruc t ion (F ig. 18- 103) oc c urs in

approximat ely 8% of renal t ransplant allograf t s (485). CT is v ery sensit iv e and spec if ic f or t ransplant hy dronephrosis. MRI is also v ery ac c urat e in t he diagnosis of renal t ransplant c omplic at ions, suc h as hy dronephrosis (92). Ly mphoc eles or perit ransplant seromas may require t reat ment in approximat ely 7% of t ransplant pat ient s, ac c ording t o one large series (269) and inf ec t ion of a c ollec t ion is c onsist ent w it h absc ess (F ig. 18- 104). T hese may ext rinsic ally c ompress t he adjac ent v essels. Post - t ransplant ly mphoprolif erat iv e disorder (PT LD) (F ig. 18- 105) may oc c ur and c ause renal art ery st enosis or hy dronephrosis (308).

F igure 18- 102 T ransplant renal v ein t hrombosis. T he t ransplant renal v ein show s absenc e of normal c ont rast opac if ic at ion (ar r ow ) during exc ret ory phase images in a pat ient w it h t ransplant dy sf unc t ion.

P.1297

Radiofrequency Ablation of Renal Mass In a small number of hospit als, radiof requenc y ablat ion (RF A) has inc reased in use as alt ernat iv e t o nephrec t omy f or selec t ed renal masses (162) (F ig. 18106). Ev en in t hese inst it ut ions, laparosc opic or open surgery is usually t he st andard of c are. In c ert ain sit uat ions, as pat ient s w it h a prev ious part ial or t ot al nephrec t omy , a c ont raindic at ion prev ent ing nephrec t omy suc h as high surgic al risk pat ient s, or in pat ient s w ho ref use open surgery , RF A may be indic at ed as an alt ernat iv e t o expec t ant management (138). It may be usef ul

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2801

18 - The Kidney and Ureter in pat ient s w ho need nephron sparing due t o mult iple lesions in diseases suc h as VHL.

F igure 18- 103 T ransplant hy dronephrosis. On pelv ic CT of t ransplant ed kidney , moderat e hy dronephrosis is present (ar r ow s). T he t ransplant uret er w as obst ruc t ed w it hin a hernia (not show n).

T he RF A proc edure begins w it h proper sc reening of t he pat ient f or risk f ac t ors t hat w ould prec lude a large needle plac ement , suc h as c oagulopat hy . Imaging ev aluat ion should be c omplet ed t o prev ent loc alized t herapy in a pat ient w it h dif f use sy st emic met ast ases. Alt hough general anest hesia and c onsc ious sedat ion hav e been desc ribed in t he lit erat ure, adequat e sedat ion is c ruc ial bec ause of t he disc omf ort assoc iat ed w it h t he proc edure (138,163). Biopsy should be c onsidered bef ore ablat ion, bec ause a large perc ent age of renal lesions ref erred f or RF A are not ac t ually RCCs (520). Ult rasound, CT , or rarely MRI may be used t o guide needle plac ement . Ult rasound c an prov ide real- t ime guidanc e f or needle plac ement , but of t en t he ablat ion sit e bec omes nonv isible ow ing t o gas generat ed during t he proc edure (300). CT does not suf f er f rom t his limit at ion in c ase addit ional port ions of t he t umor require addit ional needle plac ement s f or ablat ion. T he RF A may be perf ormed perc ut aneously or in c onjunc t ion w it h loc alized surgic al ac c ess by t he urologist . A v ariet y of probes are c ommerc ially av ailable, and t here is some v ariabilit y in t he met hods of needle c ooling and prev ent ion of unint ended c harring. T he size of t he ablat ion def ec t also v aries w it h t he t y pe of probe. Af t er t he proc edure, in- pat ient

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2802

18 - The Kidney and Ureter monit oring and laborat ory ev aluat ion is needed bec ause of t he possibilit y of c omplic at ion or need f or v asc ular int erv ent ion. A c ompet ing t ec hnology is

c ry oablat ion, w hic h uses ext reme c old t o dest roy t umor c ells in t he same w ay t hat RF A use radiof requenc y and impedanc e. In t he periproc edure period, f luid and gas may be assoc iat ed w it h t he ablat ed t issue at t he RF A sit e. T he gas and st randing ev ent ually resolv e, leav ing a nonenhanc ing def ec t in t he parenc hy ma of t he kidney . Unlike open surgery , RF A requires f requent f ollow - up imaging by mult iphase CT or MRI t o det ec t residual enhanc ing t umor t hat might require re- ablat ion. Mult iple st udies are perf ormed in t he f irst 6 mont hs, w hen risk of rec urrenc e is highest . Subsequent imaging st udies may be perf ormed on a semiannual basis (138,163). F or t umors larger t han 4 c m, t here is a signif ic ant rat e of need f or reablat ion (162). On c ont rast ed CT , t he radiographic f eat ures and ev olut ion of radiof requenc y ablat ion of renal t umors v aries based on t he loc at ion of t he t umor w it hin t he kidney . Cent ral renal t umors appear af t er ablat ion as a hy podense, w edge- shaped def ec t w it hout enhanc ement . T here may be f at at t enuat ion loc at ed bet w een t he ablat ed lesion and normal kidney . Exophy t ic masses also show absenc e of enhanc ement af t er ablat ion but ret ain t heir original shape (F ig. 18- 106C). Residual t umor af t er ablat ion demonst rat es f oc al c ont rast enhanc ement w it hin t he ablat ed region (324). On MRI, a 15% inc rease in ROI P.1298 using t he same T 1- w eight ed paramet ers suggest s residual t umor (214). How ev er, small areas of v iable t umor may persist in regions t hat do not enhanc e (417).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2803

18 - The Kidney and Ureter F igure 18- 104 T ransplant kidney absc ess. A: On CT , a c omplex lesion (ar r ow s) is present in t he t ransplant renal hilar region. B: Cont rast enhanc ed T 1- w eight ed MRI show s c omplexit y of t he lesion w it h peripheral enhanc ement and areas of c ent ral nec rosis (ar r ow heads). Post - t ransplant ly mphoprolif erat iv e disease c ould hav e t his appearanc e.

T he most c ommon c omplic at ions of ablat ion proc edures are hemat oma, pain, and paraest hesia at t he skin w here t he needle is plac ed. Complic at ions oc c ur in 11% of pat ient s, but major c omplic at ions and deat h are rare (244). Hemat omas may oc c ur, but rarely require t ransf usion (162). Ov erall, RF A is a saf e proc edure t hat is w ell t olerat ed by pat ient s and has a low c omplic at ion rat e (432).

F igure 18- 105 Post - t ransplant ly mphoprolif erat iv e disease. A: Unc ont rast ed CT demonst rat es a large mass in t he t ransplant kidney hilum (arrow s). B: Cont rast ed MRI show s mild het erogeneous enhanc ement of t he mass (ar r ow s). (Court esy of Robert Lopez- Ben).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2804

18 - The Kidney and Ureter

F igure 18- 106 Radiof requenc y ablat ion of renal t umor. A: CT during ablat ion show s met allic t y nes (ar r ow ) of t he ablat ion needle w it hin a renal mass. B: Image obt ained immediat ely af t er t he ablat ion demonst rat es gas in t he ablat ion sit e. C : F ollow - up c ont rast ed CT show s lac k of abnormal enhanc ement (ar r ow head) c onf irming t he ablat ion of t he mass.

P.1299

References 1. Abeshouse BS, Bhisit kul I. Crossed renal ec t opia w it h and w it hout f usion. Ur ologia Int er nat ionalis 1959; 9:63–91. 2. Abrams HL, Spiro R, Goldst ein N. Met ast ases in c arc inoma; analy sis of 1000 aut opsied c ases. Canc er 1950:3(1):74–85. 3. Ac 'h S, Chapuis H, Mot t et N. Met ac hronous renal onc oc y t omat osis. Ur ologia Int er nat ionalis 2003;70(3):241–243. 4. Af sar H, Y agc i F , Met o S, et al. Hy dat id disease of t he kidney : ev aluat ion and f eat ures of diagnost ic proc edures. J Ur ol 1994;151(3):567–570.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2805

18 - The Kidney and Ureter

5. Agrons GA, Wagner BJ, Dav idson AJ, et al. Mult iloc ular c y st ic renal t umor in c hildren: radiologic - pat hologic c orrelat ion. Radiogr aphic s 1995;15(3):653–669. 6. Ambos MA, Bosniak MA, Maday ag MA, et al. Inf ilt rat ing neoplasms of t he kidney . Am J Roent genol 1977;129(5):859–864. 7. Americ an Joint Commit t ee on Canc er. Kidney . In: Greene F L, Page DL, F leming ID, et al., ed. AJCC c anc er st aging m anual, 6t h ed. New Y ork: Springer;2002:323–328. 8. Americ an Joint Commit t ee on Canc er. Renal pelv is and uret er. In: Greene F L, Page DL, F leming ID, et al., ed. AJCC c anc er st aging m anual, 6t h ed. New Y ork: Springer;2002:329–334. 9. Amin MB, Crot t y T B, T ic koo SK, et al. Renal onc oc y t oma: a reappraisal of morphologic f eat ures w it h c linic opat hologic f indings in 80 c ases. Am J Sur g Pat hol 1997;21(1):1–12. 10. Andres A, Rev illa Y , Ramos A, et al. Helic al c omput ed t omography angiography is t he most ef f ic ient t est t o assess v asc ular c alc if ic at ions in t he iliac art erial sec t or in renal t ransplant c andidat es. T r ansplant Pr oc 2003;35(5):1682–1683. 11. Ant on- Culv er H, Lee- F eldst ein A, T ay lor T H. Oc c upat ion and bladder c anc er risk. Am J Epidem iol 1992;136(1):89–94. 12. Ant onelli A, Port esi E, Cozzoli A, et al. T he c ollec t ing duc t c arc inoma of t he kidney : a c y t ogenet ic al st udy . Eur Ur ol 2003;43(6): 680–685. 13. Aspelin P, Aubry P, F ransson SG, et al. Nephrot oxic ef f ec t s in high- risk pat ient s undergoing angiography . N Engl J Med 2003; 348(6):491–499. 14. At asoy C, Y agc i C, F it oz S, et al. Cross- sec t ional imaging in uret er t umors: f indings and st aging ac c urac y of v arious modalit ies. Clin Im aging 2001;25(3):197–202. 15. Av ery RA, Harris JE, Dav is CJ Jr, et al. Renal medullary c arc inoma: c linic al and t herapeut ic aspec t s of a new ly desc ribed t umor. Canc er 1996;78(1):128–132. 16. Ay res R, Curry NS, Gordon L, et al. Renal met ast ases f rom ost eogenic sarc oma. Ur ologic Radiology 1985;7(1):39–41. 17. Bae KT , Commean PK, Lee J. Volumet ric measurement of renal c y st s and parenc hy ma using MRI: phant oms and pat ient s w it h poly c y st ic kidney disease. J Com put Assist T om og 2000;24(4): 614–619. P.1300

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2806

18 - The Kidney and Ureter 18. Bakir AA, Hasnain M, Y oung S, et al. Dialy sis- assoc iat ed renal c y st ic disease resembling aut osomal dominant poly c y st ic kidney disease: a report of t w o c ases. Am J Nephr ol 1999;19(4), 519–522. 19. Ball DS, F riedman AC, Hart man DS, et al. Sc ar sign of renal onc oc y t oma: magnet ic resonanc e imaging appearanc e and lac k of spec if ic it y . Ur ol Radiol 1986;8(1):46–48. 20. Banner MP, Pollac k HM, Chat t en J, et al. Mult iloc ular renal c y st s: radiologic - pat hologic c orrelat ion. Am J Roent genol 1981;136(2): 239–247. 21. Baron RL, Mc Clennan BL, Lee JK, et al. Comput ed t omography of t ransit ional- c ell c arc inoma of t he renal pelv is and uret er. Radiology 1982;144(1):125–130. 22. Bart h KH, Menon M. Renal onc oc y t oma. F urt her diagnost ic observ at ions. Diagnost ic Im aging 1980;49(5):259–265. 23. Bav erst oc k R, Simons R, Mc Loughlin M. Sev ere blunt renal t rauma: a 7y ear ret rospec t iv e rev iew f rom a prov inc ial t rauma c ent re. Can J Ur ol 2001;8(5):1372–1376. 24. Bec kw it h JB, Palmer NF . Hist opat hology and prognosis of Wilms t umors: result s f rom t he F irst Nat ional Wilms T umor St udy . Canc er 1978;41(5):1937–1948.

25. Begin LR, Guy L, Jac obson SA, et al. Renal c arc inoid and horseshoe kidney : a f requent assoc iat ion of t w o rare ent it ies—a c ase report and rev iew of t he lit erat ure. J Sur g Onc ol 1998;68(2):113–119. 26. Behar JV, Nelson RC, Zidar JP, et al. T hin- sec t ion mult idet ec t or CT angiography of renal art ery st ent s. Am J Roent genol 2002; 178(5):1155–1159. 27. Bell T V, F enlon HM, Dav ison BD, et al. Unenhanc ed helic al CT c rit eria t o dif f erent iat e dist al uret eral c alc uli f rom pelv ic phlebolit hs. Radiology 1998;207(2):363–367. 28. Bellman GC, Y amaguc hi R. Spec ial c onsiderat ions in endopy elot omy in a horseshoe kidney . I 1996, 47(4):582–585. 29. Belv ille JS, Morgent aler A, Loughlin KR, et al. Spont aneous perinephric and subc apsular renal hemorrhage: ev aluat ion w it h CT , US, and angiography . Radiology 1989;172(3):733–738. 30. Bernardino ME, deSant os LA, Johnson DE, et al. Comput ed t omography in t he ev aluat ion of post - nephrec t omy pat ient s. Radiology 1979;130(1):183–187.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2807

18 - The Kidney and Ureter 31. Bert ini JE Jr, F lec hner SM, Miller P, et al. T he nat ural hist ory of t raumat ic branc h renal art ery injury . J Ur ol 1986, 135(2):228–230.

32. Bhat t GM, Bernardino ME, Graham SD Jr. CT diagnosis of renal met ast ases. J Com put Assist T om og 1983;7(6):1032–1034. 33. Bielsa O, Lloret a J, Gelabert - Mas A. Cy st ic renal c ell c arc inoma: pat hologic al f eat ures, surv iv al and implic at ions f or t reat ment . Br J Ur ol 1998;82(1):16–20. 34. Birnbaum BA, Bosniak MA, Krinsky GA, et al. Renal c ell c arc inoma: c orrelat ion of CT f indings w it h nuc lear morphologic grading in 100 t umors. Abdom Im aging 1994;19(3):262–266. 35. Blac her EJ, Johnson DE, Abdul- Karim F W, et al. Squamous c ell c arc inoma of renal pelv is. Ur ology 1985;25(2):124–126. 36. Blake SP, Mc Nic holas MM, Rapt opoulos V. Nonopaque c ry st al deposit ion c ausing uret eric obst ruc t ion in pat ient s w it h HIV undergoing indinav ir t herapy . Am J Roent genol 1998;171(3):717–720. 37. Blandino A, Gaet a M, Minut oli F , et al. MR urography of t he uret er. Am J Roent genol 2002;179(5):1307–1314. 38. Blankenship B, Earls JP, T alner LB. Renal v ein t hrombosis af t er v asc ular pedic le injury . Am J Roent genol 1997;168(6):1574. 39. Blic kman JG, Bramson RT , Herrin JT . Aut osomal rec essiv e poly c y st ic kidney disease: long–t erm sonographic f indings in pat ient s surv iv ing t he neonat al period. Am J Roent genol 1995; 164(5):1247–1250. 40. Boat man DL, Kolln CP, F loc ks RH. Congenit al anomalies assoc iat ed w it h horseshoe kidney . J Ur ol 1972;107(2):205–207. 41. Bogan ML, Kopec ky KK, Kraf t JL, et al. Needle biopsy of renal allograf t s: c omparison of t w o t ec hniques. Radiology 1990;174(1): 273–275. 42. Bokhari SW, F axon DP. Current adv anc es in t he diagnosis and t reat ment of renal art ery st enosis. Rev Car diov asc Med 2004;5(4): 204–215. 43. Boone T B, Gilling PJ, Husmann DA. Uret eropelv ic junc t ion disrupt ion f ollow ing blunt abdominal t rauma. J Ur ol 1993;150(1): 33–36. 44. Boridy IC, Kaw ashima A, Goldman SM, et al. Ac ut e uret erolit hiasis: nonenhanc ed helic al CT f indings of perinephric edema f or predic t ion of degree of uret eral obst ruc t ion. Radiology 1999; 213(3):663–667. 45. Boridy IC, Nikolaidis P, Kaw ashima A, et al. Uret erolit hiasis: v alue of t he t ail sign in dif f erent iat ing phlebolit hs f rom uret eral c alc uli at nonenhanc ed helic al CT . Radiology 1999;211(3): 619–621.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2808

18 - The Kidney and Ureter 46. Bosniak MA. T he c urrent radiologic al approac h t o renal c y st s. Radiology 1986;158(1):1–10. 47. Bosniak MA. T he small (less t han or equal t o 3.0 c m) renal parenc hy mal t umor: det ec t ion, diagnosis, and c ont rov ersies. Radiology 1991;179(2):307–317. 48. Bosniak MA, Megibow AJ, Hulnic k DH, et al. CT diagnosis of renal angiomy olipoma: t he import anc e of det ec t ing small amount s of f at . Am J Roent genol 1988;151(3):497–501. 49. Bov a JG, Pot t er JL, Arev alos E, et al. Renal and perirenal inf ec t ion: t he role of c omput erized t omography . J Ur ol 1985;133(3): 375–378. 50. Brac ken RB. Renal c arc inoma: c linic al aspec t s and t herapy . Sem in Roent genol 1987;22(4):241–247. 51. Bradley WG Jr, Jac obs RP, T rew PA, et al. Renal v ein t hrombosis: oc c urrenc e in membranous glomerulonephropat hy and lupus nephrit is. Radiology 1981;139(3):571–576.

52. Brandes SB, Mc Aninc h JW. Rec onst ruc t iv e surgery f or t rauma of t he upper urinary t rac t . Ur ol Clin Nor t h Am 1999;26(1):183–199. 53. Bree RL, Sc hult z SR, Hay es R. Large inf ilt rat ing renal t ransit ional c ell c arc inomas: CT and ult rasound f eat ures. J Com put Assist T om ogr 1990;14(3):381–385. 54. Brierly RD, T homas PJ, Harrison NW, et al. Ev aluat ion of f ine- needle aspirat ion c y t ology f or renal masses. Br J Ur ol Int 2000; 85(1):14–18. 55. Brow n ED, Brow n JJ, Ket t rit z U, et al. Renal absc esses: appearanc e on gadolinium- enhanc ed magnet ic resonanc e images. Abdom Im aging 1996;21(2):172–176. 56. Bruc e LM, Croc e MA, Sant aniello JM, et al. Blunt renal art ery injury : inc idenc e, diagnosis, and management . Am Sur g 2001; 67(6):550–554. 57. Brun M, Maugey - Laulom B, Eurin D, et al. Prenat al sonographic pat t erns in aut osomal dominant poly c y st ic kidney disease: a mult ic ent er st udy . Ult r asound Obst et Gy nec ol 2004;24(1):55–61. 58. Brunet on JN, Drouillard J, Laurent F , et al. Imaging of renal met ast ases. J Radiol 1988;69(11):639–643. 59. Buc ek RA, Puc hner S, Reit er M, et al. Mult idet ec t or CT angiography w it h perf usion analy sis in t he surv eillanc e of renal art ery st ent s. J Endov asc T her 2004;11(2):139–143.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2809

18 - The Kidney and Ureter 60. Buc kley JA, Urban BA, Soy er P, et al. T ransit ional c ell c arc inoma of t he renal pelv is: a ret rospec t iv e look at CT st aging w it h pat hologic c orrelat ion. Radiology 1996;201(1):94–198. 61. Campos A, F igueroa ET , Gunasekaran S, et al. Early present at ion of t uberous sc lerosis as bilat eral renal c y st s. J Ur ol 1993;149(5):1077–1079. 62. Cano JY , D'Alt orio RA. Renal liposarc oma: c ase report . J Ur ol 1976;115(6):47–49.

63. Caoili EM, Bude RO, Higgins EJ, et al. Ev aluat ion of sonographic ally guided perc ut aneous c ore biopsy of renal masses. Am J Roent genol 2002;179:373–378. 64. Caoili EM, Cohan RH, Korobkin M, et al. Urinary t rac t abnormalit ies: init ial experienc e w it h mult i- det ec t or row CT urography . Radiology 2002;222:353–360. 65. Caoili EM, Inampudi P, Cohan RH, et al. Opt imizat ion of mult i- det ec t or row CT urography : ef f ec t of c ompression, saline administ rat ion, and prolongat ion of ac quisit ion delay . Radiology 2005;235(1):116–123. 66. Carlos RC, Axelrod DA, Ellis JH, et al. Inc orporat ing pat ient - c ent ered out c omes in t he analy sis of c ost - ef f ec t iv eness: imaging st rat egies f or renov asc ular hy pert ension. Am J Roent genol 2003; 181(6):1653–1661. 67. Carroll PR, Mc Aninc h JW, Klost erman P, et al. Renov asc ular t rauma: risk assessment , surgic al management , and out c ome. J T r aum a 1990;30(5):547–552. 68. Cart er AR, Horgan JG, Jennings T A, et al. T he junc t ional parenc hy mal def ec t : a sonographic v ariant of renal anat omy . Radiology 1985;154(2):499–502. 69. Casper KA, Donnelly LF , Chen B, et al. T uberous sc lerosis c omplex: renal imaging f indings. Radiology 2002;225(2):451–456. 70. Cass AS, Luxenberg M. T raumat ic t hrombosis of a segment al branc h of t he renal art ery . J Ur ol 1987;137(6):1115–1116. P.1301 71. Cass AS, Luxenberg M, Gleic h P, et al. Clinic al indic at ions f or radiographic ev aluat ion of blunt renal t rauma. J Ur ol 1986; 136(2):370–371. 72. Cat alano C, F raioli F , Laghi A, et al. High- resolut ion mult idet ec t or CT in t he preoperat iv e ev aluat ion of pat ient s w it h renal c ell c arc inoma. Am J Roent genol 2003;180(5):1271–1277.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2810

18 - The Kidney and Ureter 73. Cat alano O, Nunziat a A, Alt ei F , et al. Suspec t ed uret eral c olic : primary helic al CT v ersus selec t iv e helic al CT af t er unenhanc ed radiography and sonography . Am J Roent genol 2002;178(2): 379–387.

74. Chao D, Zisman A, Pant uc k AJ, et al. Collec t ing duc t renal c ell c arc inoma: c linic al st udy of a rare t umor. J Ur ol 2002;167(1): 71–74. 75. Chao DH, Zisman A, Pant uc k AJ, et al. Changing c onc ept s in t he management of renal onc oc y t oma. Ur ology 2002;59(5):635–642. 76. Chapman AB, Guay - Woodf ord LM, Grant ham JJ, et al. Renal st ruc t ure in early aut osomal- dominant poly c y st ic kidney disease (ADPKD): T he Consort ium f or Radiologic Imaging St udies of Poly c y st ic Kidney Disease (CRISP) c ohort . Kidney Int 2003; 64(3):1035–1045. 77. Charles AK, Vujanic GM, Berry PJ. Renal t umours of c hildhood. Hist opat hology 1998;32(4):293–309. 78. Chen MY , Zagoria RJ. Can nonc ont rast helic al c omput ed t omography replac e int rav enous urography f or ev aluat ion of pat ient s w it h ac ut e urinary t rac t c olic ? J Em er g Med 1999;17(2):299–303. 79. Chen MY , Zagoria RJ, Saunders HS, et al. T rends in t he use of unenhanc ed helic al CT f or ac ut e urinary c olic . Am J Roent genol 1999;173(6):1447–1450. 80. Chin KC, Perry GJ, Dow ling JP, et al. Primary T - c ell- ric h B- c ell ly mphoma in t he kidney present ing w it h ac ut e renal f ailure and a sec ond malignanc y . Pat hology 1999;31(4):325–327. 81. Cho C, F riedland GW, Sw enson RS. Ac quired renal c y st ic disease and renal neoplasms in hemodialy sis pat ient s. Ur ologic Radiology 1984, 6(3–4), 153–157. 82. Choi H, Almagro UA, Mc Manus JT , et al. Renal onc oc y t oma. A c linic opat hologic st udy . Canc er 1983;51(10):1887–1896. 83. Choi JH, Choi GB, Shim KN, et al. Bilat eral primary renal non- Hodgkin's ly mphoma present ing w it h ac ut e renal f ailure: suc c essf ul t reat ment w it h sy st emic c hemot herapy . Ac t a Haem at ologic a 1997;97(4):231–235. 84. Choy ke PL, F illing- Kat z MR, Shaw ker T H, et al. Von Hippel- Lindau disease: radiologic sc reening f or v isc eral manif est at ions. Radiology 1990;174(3 Pt 1):815–820. 85. Choy ke PL, F rank JA, Girt on ME, et al. Dy namic Gd- DT PA- enhanc ed MR imaging of t he kidney : experiment al result s. Radiology 1989;170(3 Pt 1):713–720. 86. Choy ke PL, Glenn GM, Walt her MM, et al. Von Hippel- Lindau disease: genet ic , c linic al, and imaging f eat ures. Radiology 1995; 194(3):629–642.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2811

18 - The Kidney and Ureter 87. Choy ke PL, Glenn GM, Walt her MM, et al. T he nat ural hist ory of renal lesions in v on Hippel- Lindau disease: a serial CT st udy in 28 pat ient s. Am J Roent genol 1992;159(6):1229–1234. 88. Choy ke PL, Whit e EM, Zeman RK, et al. Renal met ast ases: c linic opat hologic and radiologic c orrelat ion. Radiology 1987;162(2): 359- 363. 89. Chuang CK, Lai MK, Chang PL, et al. Xant hogranulomat ous py elonephrit is: experienc e in 36 c ases. J Ur ol 1992;147(2):333- 336. 90. Coc hran ST , Krasny RM, Danov it c h GM, et al. Helic al CT angiography f or examinat ion of liv ing renal donors. Am J Roent genol 1997;168:1569–1573. 91. Cohan RH, Sherman LS, Korobkin M, et al. Renal masses: assessment of c ort ic omedullary - phase and nephrographic - phase CT sc ans. Radiology 1995;196(2):445–451.

92. Cohnen M, Brause M, May P, et al. Cont rast - enhanc ed MR urography in t he ev aluat ion of renal t ransplant s w it h urologic al c omplic at ions. Clin Nephr ol 2002;58(2):111–117. 93. Coleman BG, Arger PH, Mint z MC, et al. Hy perdense renal masses: a c omput ed t omographic dilemma. Am J Roent genol 1984;143(2):291–294. 94. Coll DM, Hert s BR, Dav ros WJ, et al. Preoperat iv e use of 3D v olume rendering t o demonst rat e renal t umors and renal anat omy . Radiogr aphic s 2000;20(2):431–438. 95. Coll DM, Varanelli MJ, Smit h RC. Relat ionship of spont aneous passage of uret eral c alc uli t o st one size and loc at ion as rev ealed by unenhanc ed helic al CT . Am J Roent genol 2002;178(1): 101–103. 96. Coric a F A, Ic zkow ski KA, Cheng L, et al. Cy st ic renal c ell c arc inoma is c ured by resec t ion: a st udy of 24 c ases w it h long- t erm f ollow up. J Ur ol 1999;161(2):408–411. 97. Corman JM, Penson DF , Hur K, et al. Comparison of c omplic at ions af t er radic al and part ial nephrec t omy : result s f rom t he Nat ional Vet erans Administ rat ion Surgic al Qualit y Improv ement Program. Br J Ur ol Int 2000;86(7):782–789. 98. Corr P, Hac king G. Embolizat ion in t raumat ic int rarenal v asc ular injuries. Clin Radiol 1991;43(4):262–264. 99. Crot t y KL, Orihuela E, Warren MM. Rec ent adv anc es in t he diagnosis and t reat ment of renal art eriov enous malf ormat ions and f ist ulas. J Ur ol 1993;150(5 Pt 1):1355–1359.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2812

18 - The Kidney and Ureter 100. Cunnif f C, Kirby RS, Senner JW, et al. Deat hs assoc iat ed w it h renal agenesis: a populat ion- based st udy of birt h prev alenc e, c ase asc ert ainment , and et iologic het erogeneit y . T er at ology 1994;50(3):200–204. 101. Curry NS, Broc k G, Met c alf JS, et al. Hy perdense renal mass: unusual CT appearanc e of a benign renal c y st . Ur ologic Radiology 1982;4(1):33–35.

102. Curry NS, Chung CJ, Gordon B. Unilat eral renal c y st ic disease in an adult . Abdom Im aging 1994;19(4):366–368. 103. Curry NS, Coc hran ST , Bissada NK. Cy st ic renal masses: ac c urat e Bosniak c lassif ic at ion requires adequat e renal CT . Am J Roent genol 2000;175(2):339–342. 104. Curry NS, Reinig J, Sc habel SI, et al. An ev aluat ion of t he ef f ec t iv eness of CT v s. ot her imaging modalit ies in t he diagnosis of at y pic al renal masses. Inv est Radiol 1984;19(5):447–454. 105. Curry NS, Sc habel SI, Bet sill WL Jr. Small renal neoplasms: Diagnost ic Imaging, pat hologic f eat ures, and c linic al c ourse. Radiology 1986;158(1):113–117. 106. Cy ran KM, Kenney PJ. Asy mpt omat ic renal absc ess: ev aluat ion w it h gadolinium DT PA- enhanc ed MRI. Abdom Im aging 1994; 19(3):267–269. 107. d'Arc hambeau O, Maes M, De Sc hepper AM. T he pelv ic c ongest ion sy ndrome: role of t he “ nut c rac ker phenomenon” and result s of endov asc ular t reat ment . JBR-BT R 2004;87(1):1–8. 108. Da'as N, Polliac k A, Cohen Y , et al. Kidney inv olv ement and renal manif est at ions in non- Hodgkin's ly mphoma and ly mphoc y t ic leukemia: a ret rospec t iv e st udy in 700 pat ient s. Eur J Haem at ol 2001;67(3):158–164. 109. Dac hman AH, New mark GM, Mit c hell MT , et al. Helic al CT examinat ion of pot ent ial kidney donors. Am J Roent genol 1998; 171(1):193–200. 110. Dahlene DH Jr, St anley RJ, Koehler RE, et al. Abdominal t uberc ulosis: CT f indings. J Com put Assist T om ogr 1984;8(3):443–445. 111. Dalla- Palma L, Pozzi- Muc elli F , di Donna A, et al. Cy st ic renal t umors: US and CT f indings. Ur ologic Radiology 1990;12(2):67–73. 112. Dalt on D, Neiman H, Gray hac k JT . T he nat ural hist ory of simple renal c y st s: a preliminary st udy . J Ur ol 1986;135(5):905–908. 113. Daniel WW Jr, Hart man GW, Wit t en DM, et al. Calc if ied renal masses. A rev iew of t en y ears experienc e at t he May o Clinic . Radiology 1972;103(3):503–508.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2813

18 - The Kidney and Ureter 114. Daskalopoulos G, Kary ot is I, Heret is I, et al. Spont aneous perirenal hemorrhage: a 10- y ear experienc e at our inst it ut ion. Int Ur ol Nephr ol 2004;36(1):15–19. 115. Dav idson AJ, Hay es WS, Hart man DS, et al. Renal onc oc y t oma and c arc inoma: f ailure of dif f erent iat ion w it h CT . Radiology 1993;186:693–696. 116. Dav is CJ Jr, Most of i F K, Sest erhenn IA. Renal medullary c arc inoma. T he sev ent h sic kle c ell nephropat hy . Am J Sur g Pat hol 1995;19(1):1–11. 117. Day al H, Kinman J. Epidemiology of kidney c anc er. Sem in Onc ol 1983;10(4):366–377. 118. de Sc hepper A. “ Nut c rac ker” phenomenon of t he renal v ein and v enous pat hology of t he lef t kidney . Jour nal Belge de Radiologie 1972;55(5):507–511. 119. Dec het CB, Bost w ic k DG, Blut e ML, et al. Renal onc oc y t oma: mult if oc alit y , bilat eralism, met ac hronous t umor dev elopment and c oexist ent renal c ell c arc inoma. J Ur ol 1999;162(1):40–42. 120. Del Pizzo JJ, Sklar GN, Y ou- Cheong JW, et al. Helic al c omput erized t omography art eriography f or ev aluat ion of liv e renal donors undergoing laparosc opic nephrec t omy . Ur ology 1999;162(1): 31–34. P.1302 121. Dent on KJ, Cot t on DW, Nakielny RA, et al. Sec ondary t umour deposit s in needle biopsy t rac ks: an underest imat ed risk? J Clin Pat hol 1990;43(1):83.

122. Didier D, Rac le A, Et iev ent JP, et al. T umor t hrombus of t he inf erior v ena c av a sec ondary t o malignant abdominal neoplasms: US and CT ev aluat ion. Radiology 1987;162(1 Pt 1):83–89. 123. Dinkel HP, Danuser H, T riller J. Blunt renal t rauma: minimally inv asiv e management w it h mic roc at het er embolizat ion experienc e in nine pat ient s. Radiology 2002;223(3):723–730. 124. Dinsmore BJ, Pollac k HM, Banner MP. Calc if ied t ransit ional c ell c arc inoma of t he renal pelv is. Radiology 1988;167(2):401–404. 125. Dobronski P, Czaplic ki M, Kozminska E, et al. Collec t ing (Bellini) duc t c arc inoma of t he kidney —- c linic al, radiologic and immunohist oc hemic al f indings. Int Ur ol Nephr ol 1999;31(5): 601–609. 126. Donat SM, Donat PE. Int rat horac ic kidney : a c ase report w it h a rev iew of t he w orld lit erat ure. J Ur ol 1988;140(1):131–133. 127. Doroshow LW, Abeshouse BS. Congenit al unilat eral solit ary kidney : report of 37 c ases and a rev iew of t he lit erat ure. Ur ologic Sur v ey 1961;11:219–229.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2814

18 - The Kidney and Ureter 128. Duf f ey BG, Choy ke PL, Glenn G, et al. T he relat ionship bet w een renal t umor size and met ast ases in pat ient s w it h v on Hippel- Lindau disease. J Ur ol 2004;172(1):63–65.

129. Dunnic k NR, Korobkin M, Clark WM. CT demonst rat ion of hy perdense renal c arc inoma. J Com put Assist T om ogr 1984;8(5): 1023–1024. 130. Emamian SA, Nielsen MB, Pedersen JF , et al. Kidney dimensions at sonography : c orrelat ion w it h age, sex, and habit us in 665 adult v olunt eers. Am J Roent genol 1993;160:83–86. 131. English WP, Pearc e JD, Crav en T E, et al. Surgic al management of renal art ery aneury sms. J Vasc ular Sur g 2004;40(1):53–60. 132. Ergen F B, Hussain HK, Caoili EM, et al. MRI f or preoperat iv e st aging of renal c ell c arc inoma using t he 1997 T NM c lassif ic at ion: c omparison w it h surgic al and pat hologic st aging. Am J Roent genol 2004;182(1):217–225. 133. Esc hw ege P, Saussine C, St eic hen G, et al. Radic al nephrec t omy f or renal c ell c arc inoma 30 mm. or less: long- t erm f ollow result s. J Ur ol 1996;155(4):1196–1199. 134. Eshed I, Elias S, Sidi AA. Diagnost ic v alue of CT - guided biopsy of indet erminat e renal masses. Clin Radiol 2004;59(3):262–267. 135. Ev ans WP, Resnic k MI. Horseshoe kidney and urolit hiasis. J Ur ol 1981;125(5):620–621. 136. F aenza A, Spolaore R, Poggioli G, et al. Renal art ery st enosis af t er renal t ransplant at ion. Kidney Int 1983;23(suppl. 14):S54–S59. 137. F an ZM, Zeng QY , Huo JW, et al. Mac ronodular mult i- organs t uberc uloma: CT and MR appearanc es. J Gast r oent er ol 1998; 33(2):285–288. 138. F arrell MA, Charboneau WJ, DiMarc o DS, et al. Imaging- guided radiof requenc y ablat ion of solid renal t umors. Am J Roent genol 2003;180(6):1509–1513. 139. F arres MT , Pedron P, Gat t egno B, et al. Helic al CT and 3D rec onst ruc t ion of uret eropelv ic junc t ion obst ruc t ion: ac c urac y in det ec t ion of c rossing v essels. J Com put Assist T om ogr 1998;22(2): 300–303. 140. F arrow GM, Harrison EG Jr, Ut z DC. Sarc omas and sarc omat oid and mixed malignant t umors of t he kidney in adult s. III. Canc er 1968;22(3):556–563. 141. F ederle MP, Y agan N, Peit zman AB, et al. Abdominal t rauma: use of oral c ont rast mat erial f or CT is saf e. Radiology 1997;205(1): 91–93. 142. F ein AB, Lee JK, Balf e DM, et al. Diagnosis and st aging of renal c ell c arc inoma: a c omparison of MR imaging and CT . Am J Roent genol 1987;148(4):749–753.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2815

18 - The Kidney and Ureter

143. F eldberg MA, v an Waes PF . Mult iloc ular c y st ic renal c ell c arc inoma. Am J Roent genol 1982;138(5):953–955. 144. F elzenberg J, Nasrallah PF . Crossed renal ec t opia w it hout f usion assoc iat ed w it h hy dronephrosis in an inf ant . Ur ology 1991;38(5): 450–452. 145. F errozzi F , Bov a D, Campodonic o F . Comput ed t omography of renal met ast ases. Sem in Ult r asound CT MR 1997;18(2): 115–121. 146. F erry JA, Harris NL, Papanic olaou N, et al. Ly mphoma of t he kidney . A report of 11 c ases. Am J Sur g Pat hol 1995;19(2): 134–144. 147. F ielding JR, F ox LA, Heller H, et al. Spiral CT in t he ev aluat ion of f lank pain: ov erall ac c urac y and f eat ure analy sis. J Com put Assist T om ogr 1997:21(4):635–638. 148. F ielding JR, Silv erman SG, Rubin GD. Helic al CT of t he urinary t rac t . Am J Roent genol 1999;172(5):1199–1206. 149. F ielding JR, Silv erman SG, Samuel S, et al. Unenhanc ed helic al CT of uret eral st ones: a replac ement f or exc ret ory urography in planning t reat ment . Am J Roent genol 1998;171(4):1051–1053. 150. F ielding JR, St eele G, F ox LA, et al. Spiral c omput erized t omography in t he ev aluat ion of ac ut e f lank pain: a replac ement f or exc ret ory urography . J Ur ol 1997;157(6):2071–2073. 151. F ishman EK, Hart man DS, Goldman SM, et al. T he CT appearanc e of Wilms t umor. J Com put Assist T om ogr 1983;7(4): 659–665. 152. F ishman MC, Pollac k HM, Arger PH, et al. High prot ein c ont ent : anot her c ause of CT hy perdense benign renal c y st . J Com put Assist T om ogr 1983;7(6):1103–1106. 153. F lec hner SM, Mc Aninc h JW. Aspergillosis of t he urinary t rac t : asc ending rout e of inf ec t ion and ev olv ing pat t erns of disease. J Ur ol 1981;125(4):598–601. 154. F orman HP, Middlet on WD, Melson GL, et al. Hy perec hoic renal c ell c arc inomas: inc rease in det ec t ion at US. Radiology 1993;188(2):431–434. 155. F ow ler JE Jr, Perkins T . Present at ion, diagnosis and t reat ment of renal absc esses: 1972–1988. J Ur ol 1994;151(4):847–851. 156. F ow ler KA, Loc ken JA, Duc hesne JH, et al. US f or det ec t ing renal c alc uli w it h nonenhanc ed CT as a ref erenc e st andard. Radiology 2002;222(1):109–113. 157. F reedman BI, Souc ie JM, Chapman A, et al. Rac ial v ariat ion in aut osomal dominant poly c y st ic kidney disease. Am J Kidney Dis 2000;35(1):35–39.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2816

18 - The Kidney and Ureter 158. F ukuy a T , Honda H, Got o K, et al. Comput ed t omographic f indings of Bellini duc t c arc inoma of t he kidney . J Com put Assist T om og 1996:20(3):399–403. 159. F ult z PJ, Hampt on WR, T ot t erman SM. Comput ed t omography of py onephrosis. Abdom Im aging 1993;18(1):82–87.

160. Gat ew ood OM, Goldman SM, Marshall F F , et al. Comput erized t omography in t he diagnosis of t ransit ional c ell c arc inoma of t he kidney . J Ur ol 1982;127(5):876–887. 161. Gehrig JJ Jr, Got t heiner T I, Sw enson RS. Ac quired c y st ic disease of t he end- st age kidney . Am J Med 1985;79(5):609–620. 162. Gerv ais DA, Mc Gov ern F J, Arellano RS, et al. Radiof requenc y ablat ion of renal c ell c arc inoma. Part 1: Indic at ions, result s, and role in pat ient management ov er a 6- y ear period and ablat ion of 100 t umors. Am J Roent genol 2005;185(1):64–71. 163. Gerv ais DA, Mc Gov ern F J, Arellano RS, et al. Renal c ell c arc inoma: c linic al experienc e and t ec hnic al suc c ess w it h radio- f requenc y ablat ion of 42 t umors. Radiology 2003;226(2):417–424. 164. Gibbs GF , Hust on J 3rd, Qian Q, et al. F ollow - up of int rac ranial aneury sms in aut osomal- dominant poly c y st ic kidney disease. Kidney Int 2004;65(5):1621–1627. 165. Gill IS, Mat in SF , Desai MM, et al. Comparat iv e analy sis of laparosc opic v ersus open part ial nephrec t omy f or renal t umors in 200 pat ient s. J Ur ol 2003;170(1):64–68. 166. Gill IS, Mc Clennan BL, Kerbl K, et al. Adrenal inv olv ement f rom renal c ell c arc inoma: predic t iv e v alue of c omput erized t omography . J Ur ol 1994;152(4):1082–1085. 167. Glass RB, Dav idson AJ, F ernbac h SK. Clear c ell sarc oma of t he kidney : CT , sonographic , and pat hologic c orrelat ion. Radiology 1991;180(3):715–717. 168. Glazer GM, F ranc is IR, Gross BH, et al. Comput ed t omography of renal v ein t hrombosis. J Com put Assist T om ogr 1984;8(2): 288–293. 169. Gleason PE, Kelalis PP, Husmann DA, et al. Hy dronephrosis in renal ec t opia: inc idenc e, et iology and signif ic anc e. J Ur ol 1994; 151(6):1660–1661. 170. Goet huy s H, Van Poppel H, Oy en R, et al. T he c ase against f ine- needle aspirat ion c y t ology f or small solid kidney t umors. Eur Ur ol 1996;29(3):284–287.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2817

18 - The Kidney and Ureter

171. Goldf arb S, Spinler S, Berns JS, et al. Low - osmolalit y c ont rast media and t he risk of c ont rast - assoc iat ed nephrot oxic it y . Inv est Radiol 1993;28 (suppl 5):S7–S10. P.1303 172. Goldman SM, F aint uc h S, Ajzen SA, et al. Diagnost ic v alue of at t enuat ion measurement s of t he kidney on unenhanc ed helic al CT of obst ruc t iv e uret erolit hiasis. Am J Roent genol 2004;182(5): 1251–1254. 173. Goldman SM, F ishman EK. Upper urinary t rac t inf ec t ion: t he c urrent role of CT , ult rasound, and MRI. Sem in Ult r asound CT MRI 1991;12(4):335–360. 174. Goldman SM, F ishman EK, Hart man DS, et al. Comput ed t omography of renal t uberc ulosis and it s pat hologic al c orrelat es. J Com put Assist T om ogr 1985;9(4):771–776. 175. Goldman SM, Hart man DS, F ishman EK, et al. CT of xant hogranulomat ous py elonephrit is: radiologic - pat hologic c orrelat ion. Am J Roent genol 1984;142(5):963–969. 176. Goldman SM, Sandler CM. Urogenit al t rauma: imaging upper GU t rauma. Eur J Radiol 2004;50(1):84–95. 177. Gonc harenko V, Gerloc k AJ Jr, Kadir S, et al. Inc idenc e and dist ribut ion of v enous ext ension in 70 hy pernephromas. Am J Roent genol 1979;133(2):263–265. 178. Grundy P, Breslow N, Green DM, et al. Prognost ic f ac t ors f or c hildren w it h rec urrent Wilms t umor: result s f rom t he Sec ond and T hird Nat ional Wilms T umor St udy . J Clin Onc ol 1989;7(5): 638–647. 179. Gut ierrez OH, Burgener F A, Sc hw art z S. Coinc ident renal c ell c arc inoma and renal angiomy olipoma in t uberous sc lerosis. Am J Roent genol 1979;132(5):848–850. 180. Haas CA, Dinc hman KH, Nasrallah PF , et al. T raumat ic renal art ery oc c lusion: a 15- y ear rev iew . J T r aum a 1998;45(3):557–561. 181. Hac klander T , Mert ens H, St at t aus J, et al. Ev aluat ion of renov asc ular hy pert ension: c omparison of f unc t ional MRI and c ont rast - enhanc ed MRA w it h a rout inely perf ormed renal sc int igraphy and DSA. J Com put Assist T om ogr 2004;28(6):823–831. 182. Hadar H, Meiraz D. Renal sinus lipomat osis: dif f erent iat ion f rom spac eoc c upy ing lesion w it h aid of c omput ed t omography . Ur ology 1980;15(1):86–90.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2818

18 - The Kidney and Ureter 183. Haf ez KS, F ergany AF , Nov ic k AC. Nephron sparing surgery f or loc alized renal c ell c arc inoma: impac t of t umor size on pat ient surv iv al, t umor rec urrenc e and T NM st aging. J Ur ol 1999;162(6): 1930–1933. 184. Hageman JH, Smit h RF , Szilagy i E, et al. Aneury sms of t he renal art ery : problems of prognosis and surgic al management . Sur ger y 1978;84(4):563–572.

185. Hajdu SI, F oot e F W Jr. Angiomy olipoma of t he kidney : report of 27 c ases and rev iew of t he lit erat ure. J Ur ol 1969;102(4): 396–401. 186. Hallsc heidt PJ, T horn M, Radelef f BA, et al. Comparison of spat ial resolut ion in high- resolut ion mult islic e c omput ed t omography and digit al subt rac t ion angiography using renal spec imens. J Com put Assist T om ogr 2003;27(6):864–868. 187. Hann L, Pf ist er RC. Renal subc apsular rim sign: new et iologies and pat hogenesis. Am J Roent genol 1982;138(1):51–54. 188. Harabay ashi T , Shinohara N, Kat ano H, et al. Management of renal angiomy olipomas assoc iat ed w it h t uberous sc lerosis c omplex. J Ur ol 2004;171(1):102–105. 189. Harisinghani MG, Saini S, Weissleder R, et al. MR ly mphangiography using ult rasmall superparamagnet ic iron oxide in pat ient s w it h primary abdominal and pelv ic malignanc ies: radiographic - pat hologic c orrelat ion. Am J Roent genol 1999;172(5): 1347–1351. 190. Harmon WJ, King BF , Lieber MM. Renal onc oc y t oma: magnet ic resonanc e imaging c harac t erist ic s. J Ur ol 1996;155(3):863–867. 191. Harris AC, Zw irew ic h CV, Ly burn ID, et al. CT f indings in blunt renal t rauma. Radiogr aphic s 2001;21 Spec :S201–S214. 192. Hart man DS, Dav id CJ Jr, Goldman SM, et al. Renal ly mphoma: radiologic pat hologic c orrelat ion of 21 c ases. Radiology 1982; 144(4):759–766. 193. Hart man DS, Dav idson AJ, Dav is CJ Jr, et al. Inf ilt rat iv e renal lesions: CT sonographic - pat hologic c orrelat ion. Am J Roent genol 1988;150(5):1061–1064. 194. Hart man DS, Dav is CJ, Sanders RC, et al. T he mult iloc ulat ed renal mass: c onsiderat ions and dif f erent ial f eat ures. Radiogr aphic s 1987;7(1):29–52. 195. Hart man DS, Dav is CJ Jr, Johns T , et al. Cy st ic renal c ell c arc inoma. Ur ology 1986;28(2):145–153. 196. Hart man DS, Dav is CJ Jr, Madew ell JE, et al. Primary malignant renal t umors in t he sec ond dec ade of lif e: Wilms t umor v ersus renal c ell c arc inoma. J Ur ol 1982;127(5):888–891.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2819

18 - The Kidney and Ureter 197. Hart man DS, Weat herby E 3rd, Laskin WB, et al. Cy st ic renal c ell c arc inoma: CT f indings simulat ing a benign hy perdense c y st . Am J Roent genol 1992;159(6):1235–1237. 198. Hay es WS, Hart man DS, Sest erbenn IA. F rom t he arc hiv es of t he AF IP. Xant hogranulomat ous py elonephrit is. Radiogr aphic s 1991;11(3):485–498. 199. Healy ME, T eng SS, Moss AA. Urinif erous pseudoc y st : c omput ed t omographic f indings. Radiology 1984;153(3):757–762. 200. Hélénon O, Chrét ien Y , Paraf F , et al. Renal c ell c arc inoma c ont aining f at : demonst rat ion w it h CT . Radiology 1993;188: 429–430. 201. Heneghan JP, Dalry mple NC, Verga M, et al. Sof t - t issue “ rim” sign in t he diagnosis of uret eral c alc uli w it h use of unenhanc ed helic al CT . Radiology 1997;202(3):709–711. 202. Heneghan JP, Spielmann AL, Sheaf or DH, et al. Pseudoenhanc ement of simple renal c y st s: a c omparison of single and mult idet ec t or helic al CT . J Com put Assist T om ogr 2002;26(1):90–94. 203. Henke PK, Cardneau JD, Welling T H 3rd, et al. Renal art ery aneury sms: a 35- y ear c linic al experienc e w it h 252 aneury sms in 168 pat ient s. Ann Sur g 2001;234(4):454–462; disc ussion 462–463.

204. Herring JC, Enquist EG, Chernof f A, et al. Parenc hy mal sparing surgery in pat ient s w it h heredit ary renal c ell c arc inoma: 10- y ear experienc e. J Ur ol 2001;165(3):777–781. 205. Hersc horn S, Radomski SB, Shoskes DA, et al. Ev aluat ion and t reat ment of blunt renal t rauma. J Ur ol 1991;146(2):274–276. 206. Hert le L, Androulakakis P. Kerat inizing desquamat iv e squamous met aplasia of t he upper urinary t rac t : leukoplakia—c holest eat oma. J Ur ol 1982;127(4):631–635. 207. Hert le L, Bec ht E, Klose K, et al. Comput ed t omography in xant hogranulomat ous py elonephrit is. Eur Ur ol 1984;10(6):385–388. 208. Hert s BR. Helic al CT and CT angiography f or t he ident if ic at ion of c rossing v essels at t he uret eropelv ic junc t ion. Ur ol Clin Nor t h Am 1998;25(2):259–269. 209. Hert s BR, Baker ME. T he c urrent role of perc ut aneous biopsy in t he ev aluat ion of renal masses. Sem in Ur ol Onc ol 1995;13(4): 254–261. 210. Hes F J, F eldberg MA. Von Hippel- Lindau disease: st rat egies in early det ec t ion (renal- , adrenal- , panc reat ic masses). Eur Radiol 1999;9(4):598–610.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2820

18 - The Kidney and Ureter 211. Hiet ala SO, Ekelund L, Ljungberg B. Venous inv asion in renal c ell c arc inoma: a c orrelat iv e c linic al and radiologic st udy . Ur ol Radiol 1988;9(4):210–216. 212. Higashihara E, Aso Y , Shimazaki J, et al. Clinic al aspec t s of poly c y st ic kidney disease. J Ur ol 1992;147(2):329–332. 213. Hilpert PL, F riedman AC, Radec ki PD, et al. MRI of hemorrhagic renal c y st s in poly c y st ic kidney disease. Am J Roent genol 1986;146(6):1167–1172. 214. Ho VB, Allen SF , Hood MN, et al. Renal masses: quant it at iv e assessment of enhanc ement w it h dy namic MR imaging. Radiology 2002;224(3):695–700. 215. Hohenf ellner M, D'Elia G, Hampel C, et al. T ransposit ion of t he lef t renal v ein f or t reat ment of t he nut c rac ker phenomenon: long- t erm f ollow - up. Ur ology 2002;59(3):354–357. 216. Hohenf ellner M, Sc hult z- Lampel D, Lampel A, et al. T umor in t he horseshoe kidney : c linic al implic at ions and rev iew of embry ogenesis. J Ur ol 1992;147(4):1098–1102. 217. Hohenf ellner M, St einbac h F , Sc hult z- Lampel D, et al. T he nut c rac ker sy ndrome: new aspec t s of pat hophy siology , diagnosis and t reat ment . J Ur ol 1991;146(3):685–688.

218. Holmang S, Johansson SL. Sy nc hronous bilat eral uret eral and renal pelv ic c arc inomas: inc idenc e, et iology , t reat ment and out c ome. Canc er 2004;101(4):741–747. 219. Honda H, Cof f man CE, Berbaum KS, et al. CT analy sis of met ast at ic neoplasms of t he kidney . Comparison w it h primary renal c ell c arc inoma. Ac t a Radiologic a 1992;33(1):39–44. 220. Honda H, Mc Guire CW, Barloon T J, et al. Replac ement lipomat osis of t he kidney : CT f eat ures. J Com put Assist T om ogr 1990;14(2):229–231. 221. Honda H, Onit suka H, Nait ou S, et al. Renal art eriov enous malf ormat ions: CT f eat ures. J Com put Assist T om ogr 1991;15(2): 261–264. P.1304 222. Horan JJ, Robert son CN, Choy ke PL, et al. T he det ec t ion of renal c arc inoma ext ension int o t he renal v ein and inf erior v ena c av a: a prospec t iv e c omparison of v enac av ography and magnet ic resonanc e imaging. J Ur ol 1989;142(4):943–947. 223. Horino T , Y amamot o M, Morit a M, et al. Renal ac t inomy c osis mimic king renal t umor: c ase report . Sout h Med J 2004;97(3): 316–318.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2821

18 - The Kidney and Ureter 224. Hov sepian DM, Lev y H, Amis ES Jr, et al. MR ev aluat ion of renal spac e-

oc c upy ing lesions: diagnost ic c rit eria. Ur ologic Radiology 1990;12(2):74–79. 225. Hric ak H, T hoeni RF , Carroll PR, et al. Det ec t ion and st aging of renal neoplasms: a reassessment of MR imaging. Radiology 1988;166(3):643–649. 226. Huang EY , Masc arenhas L, GH. M. Wilms t umor and horseshoe kidney s: a c ase report and rev iew of t he lit erat ure. J Pediat r Sur g 2004;39(2):207–212. 227. Huang GJ, Israel G, Berman A, et al. Preoperat iv e renal t umor ev aluat ion by t hree- dimensional magnet ic resonanc e imaging: st aging and det ec t ion of mult if oc alit y . Ur ology 2004;64(3): 453–457. 228. Huc h Boni RA, Debat in JF , Krest in GP. Cont rast - enhanc ed MR imaging of t he kidney s and adrenal glands. Magn Res Im aging Clin N Am 1996;4(1):101–131. 229. Hudson MA, Wey man PJ, v an der Vliet AH, et al. Emphy semat ous py elonephrit is: suc c essf ul management by perc ut aneous drainage. J Ur ol 1986;136(4):884–886. 230. Hughson MD, Hennigar GR, Mc Manus JF . At y pic al c y st s, ac quired renal c y st ic disease, and renal c ell t umors in end st age dialy sis kidney s. Lab Inv est 1980;42(4):475–480. 231. Hurw it z G, Reimund E, Mopart y KR, et al. Bilat eral renal parenc hy mal malac oplakia: a c ase report . J Ur ol 1992;147(1): 115–117. 232. Ishikaw a I. Uremic ac quired c y st ic disease of kidney . Ur ology 1985;26(2):101–108. 233. Ishikaw a I, T at eishi K, Onouc hi Z, et al. Persist ent w edge- shaped c ont rast enhanc ement of t he kidney . Ur ol Radiol 1985;7(1): 45–47. 234. Isobe H, T akashima H, Higashi N, et al. Primary c arc inoid t umor in a horseshoe kidney . Int J Ur ol 2000;7(5):184–188. 235. Israel GM, Bosniak MA. Calc if ic at ion in c y st ic renal masses: is it import ant in diagnosis? Radiology 2003;226(1):47–52. 236. Israel GM, Bosniak MA, Sly w ot zky CM, et al. CT dif f erent iat ion of large exophy t ic renal angiomy olipomas and perirenal liposarc omas. Am J Roent genol 2002;179(3):769–773. 237. Jac obs JE, Sussman SK, Glic kst ein MF . Renal ly mphangiomy oma—- a rare c ause of a mult iloc ulat ed renal mass. Am J Roent genol 1989;152(2):307–308. 238. Jac obs SC, Berg SI, Law son RK. Sy nc hronous bilat eral renal c ell c arc inoma: t ot al surgic al exc ision. Canc er 1980;46(11):2341–2345.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2822

18 - The Kidney and Ureter 239. Jef f rey RB, Cardoza JD, Olc ot t EW. Det ec t ion of ac t iv e int raabdominal

art erial hemorrhage: v alue of dy namic c ont rast - enhanc ed CT . Am J Roent genol 1991;156(4):725–729. 240. Jinzaki M, T animot o A, Narimat su Y , et al. Angiomy olipoma: imaging f indings in lesions w it h minimal f at . Radiology 1997;205(2):497–502. 241. Jof f e SA, Serv aes S, Okon S, et al. Mult i- det ec t or row CT urography in t he ev aluat ion of hemat uria. Radiogr aphic s 2003;23(6): 1441–1455. 242. Johansson S, Angerv all L, Bengt sson U, et al. Uroepit helial t umors of t he renal pelv is assoc iat ed w it h abuse of phenac et in- c ont aining analgesic s. Canc er 1974;33(3):743–753. 243. Johnson CD, Dunnic k NR, Cohan RH, et al. Renal adenoc arc inoma: CT st aging of 100 t umors. Am J Roent genol 1987;148(1): 59–63. 244. Johnson DB, Solomon SB, Su LM, et al. Def ining t he c omplic at ions of c ry oablat ion and radio f requenc y ablat ion of small renal t umors: a mult iinst it ut ional rev iew . J Ur ol 2004;172(3): 874–877. 245. Jung G, Benz- Bohm G, Kugel H, et al. MR c holangiography in c hildren w it h aut osomal rec essiv e poly c y st ic kidney disease. Pediat r Radiol 1999;29(6):463–466. 246. Kaat ee R, Beek F J, de Lange EE, et al. Renal art ery st enosis: det ec t ion and quant if ic at ion w it h spiral CT angiography v ersus opt imized digit al subt rac t ion angiography . Radiology 1997;205(1): 121–127. 247. Kabala JE, Gillat t DA, Persad RA, et al. Magnet ic resonanc e imaging in t he st aging of renal c ell c arc inoma. Br J Radiol 1991; 64(764):683–689. 248. Kallman DA, King BF , Hat t ery RR, et al. Renal v ein and inf erior v ena c av a t umor t hrombus in renal c ell c arc inoma: CT , US, MRI and v enac av ography . J Com put Assist T om ogr 1992;16(2): 240–247. 249. Kanet i J, Krugliak L, Hirsc h M, et al. Rupt ure of renal angiomy olipoma: c onserv at iv e surgery . J Ur ol 1983;129(4):810–811. 250. Karst aedt N, Mc Cullough DL, Wolf man NT , et al. Magnet ic resonanc e imaging of t he renal mass. J Ur ol 1986;136(3):566–570. 251. Kat z DS, Lane MJ, Sommer F G. Unenhanc ed helic al CT of uret eral st ones: inc idenc e of assoc iat ed urinary t rac t f indings. Am J Roent genol 1996;166(6):1319–1322. 252. Kaw amot o S, Law ler LP, F ishman EK. Ev aluat ion of t he renal v enous sy st em on lat e art erial and v enous phase images w it h MDCT angiography in pot ent ial liv ing laparosc opic renal donors. Am J Roent genol 2005;184(2):539–545.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2823

18 - The Kidney and Ureter 253. Kaw amot o S, Mont gomery RA, Law ler LP, et al. Mult idet ec t or CT angiography f or preoperat iv e ev aluat ion of liv ing laparosc opic kidney donors. Am J Roent genol 2003;180(6):1633–1638. 254. Kaw ashima A, Sandler CM, Boridy IC, et al. Unenhanc ed helic al CT of uret erolit hiasis: v alue of t he t issue rim sign. Am J Roent genol 1997;168(4):997–1000. 255. Kaw ashima A, Sandler CM, Corl F M, et al. Imaging of renal t rauma: a c omprehensiv e rev iew . Radiogr aphic s 2001;21(3): 557–574. 256. Kaw ashima A, Sandler CM, Corriere JN Jr, et al. Uret eropelv ic junc t ion injuries sec ondary t o blunt abdominal t rauma. Radiology 1997;205(2):487–492.

257. Kaw ashima A, Sandler CM, Ernst RD, et al. CT ev aluat ion of renov asc ular disease. Radiogr aphic s 2000;20(5):1321–1340. 258. Kay nan AM, Rozenblit AM, F igueroa KI, et al. Use of spiral c omput erized t omography in lieu of angiography f or preoperat iv e assessment of liv ing renal donors. J Ur ol 1999;161(6):1769–1775. 259. Keeley F X Jr, Bagley DH, Kulp- Hugues D, et al. Laparosc opic div ision of c rossing v essels at t he uret eropelv ic junc t ion. J Endour ol 1996;10(2):163–168. 260. Kenney PJ, Mc Clennan BL. T he kidney . In: Lee J, Sagel S, St anley RJ, Heiken JP, eds. Com put ed body t om ogr aphy w it h MRI c or r elat ion, v ol. 2, 3rd ed. Philadelphia: Lippinc ot t - Rav en Publishers; 1998:1087–1170. 261. Kenney PJ, Panic ek DM, Wit anow ski LS. Comput ed t omography of uret eral disrupt ion. J Com put Assist T om ogr 1987;11(3):480–484. 262. Khaira HS, Plat t JF , Cohan RH, et al. Helic al c omput ed t omography f or ident if ic at ion of c rossing v essels in uret eropelv ic junc t ion obst ruc t ionc omparison w it h operat iv e f indings. Ur ology 2003;62(1):35–39. 263. Kim T S, Chung JW, Park JH, et al. Renal art ery ev aluat ion: c omparison of spiral CT angiography t o int ra- art erial DSA. Journal of Vasc ular and Int erv ent ional Radiology 1998;9(4):553–559. 264. Kim WS, Goldman SM, Gat ew ood OM, et al. Comput ed t omography in c alc if ied renal masses. J Com put Assist T om ogr 1981;5(6):855–860. 265. Kirc hin MA, Runge VM. Cont rast agent s f or magnet ic resonanc e imaging: saf et y updat e. T op Magn Reson Im aging 2003;14(5): 426–435. 266. Knudson MM, Harrison PB, Hoy t DB, et al. Out c ome af t er major renov asc ular injuries: a West ern t rauma assoc iat ion mult ic ent er report . J T r aum a 2000;49(6):1116–1122.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2824

18 - The Kidney and Ureter 267. Knudson MM, Maull KI. Nonoperat iv e management of solid organ injuries. Past , present , and f ut ure. Surg Clin Nort h Am 1999;79(6):1357–1371. 268. Kobay ashi S, Ohmori M, Akaeda T , et al. Primary adenoc arc inoma of t he renal pelv is. Report of t w o c ases and brief rev iew of lit erat ure. Ac t a Pat hologic a Japonic a 1983;33(3):589–597. 269. Koc ak T , Nane I, Ander H, et al. Urologic al and surgic al c omplic at ions in 362 c onsec ut iv e liv ing relat ed donor kidney t ransplant at ions. Ur ologia Int er nat ionalis 2004;72(3):252–256.

270. Konnak JW, Grossman HB. Renal c ell c arc inoma as an inc ident al f inding. J Ur ol 1985;134(6):1094–1096. P.1305 271. Kopka L, F isc her U, Zoeller G, et al. Dual- phase helic al CT of t he kidney : v alue of t he c ort ic omedullary and nephrographic phase f or ev aluat ion of renal lesions and preoperat iv e st aging of renal c ell c arc inoma. Am J Roent genol 1997;169(6):1573–1578. 272. Krishnan B, T ruong LD, Saleh G, et al. Horseshoe kidney is assoc iat ed w it h an inc reased relat iv e risk of primary renal c arc inoid t umor. J Ur ol 1997;157(6):2059–2066. 273. Krizanac S, Vranesic D, Oberman B. Onc oc y t omas of t he kidney . Br J Ur ol 1987;60(3):189–192. 274. Kumar R, Amparo EG, Dav id R, et al. Adult Wilms' t umor: c linic al and radiographic f eat ures. Ur ol Radiol 1984;6(3–4):164–169. 275. Lampel A, Hohenf ellner M, Sc hult z- Lampel D, et al. Urolit hiasis in horseshoe kidney s: t herapeut ic management . Ur ology 1996; 47(2):182–186. 276. Lane MJ, Kat z DS, Shah RA, et al. Ac t iv e art erial c ont rast ext rav asat ion on helic al CT of t he abdomen, pelv is, and c hest . Am J Roent genol 1998;171(3):679–685. 277. Lane RH, St ephens DH R, Reiman HM. Primary ret roperit oneal neoplasms: CT f indings in 90 c ases w it h c linic al and pat hologic c orrelat ion. Am J Roent genol 1989;152(1):83–89. 278. Lang EK. Renal, perirenal, and pararenal absc esses: perc ut aneous drainage. Radiology 1990;174(1):109–113. 279. Lang EK, Mac c hia RJ, Gay le B, et al. CT - guided biopsy of indet erminat e renal c y st ic masses (Bosniak 3 and 2F ): ac c urac y and impac t on c linic al management . Eur Radiol 2002;12(10):2518–2524.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2825

18 - The Kidney and Ureter 280. Lang EK, Mac c hia RJ, T homas R, et al. Det ec t ion of medullary and papillary nec rosis at an early st age by mult iphasic helic al c omput erized t omography . J Ur ol 2003;170(1):94–98. 281. Law son T L, Mc Clennan BL, Shirkhoda A. Adult poly c y st ic kidney disease: ult rasonographic and c omput ed t omographic appearanc e. J Clin Ult r asound 1978;6(5):297–302.

282. Lec hev allier E, Andre M, Barriol D, et al. F ine- needle perc ut aneous biopsy of renal masses w it h helic al CT guidanc e. Radiology 2000;216(2):506–510. 283. Leder RA, Dunnic k NR. T ransit ional c ell c arc inoma of t he pelv ic alic es and uret er. Am J Roent genol 1990;155(4):713–722. 284. Lee JK, Mc Clennan BL, Kissane JM. Unilat eral poly c y st ic kidney disease. Am J Roent genol 1978;130(6):1165–1167. 285. Lee JK, Mc Clennan BL, Melson GL, et al. Ac ut e f oc al bac t erial nephrit is: emphasis on gray sc ale sonography and c omput ed t omography . Am J Roent genol 1980;135(1):87–92. 286. Lemait re L, Claudon M, Dubrulle F , et al. Imaging of angiomy olipomas. Sem in Ult r asound CT MRI 1997;18(2):100–114. 287. Lemait re L, Robert Y , Dubrulle F , et al. Renal angiomy olipoma: grow t h f ollow ed up w it h CT and/or US. Radiology 1995;197(3): 598–602. 288. Leo ME, Pet rou SP, Barret t DM. T ransit ional c ell c arc inoma of t he kidney w it h v ena c av al inv olv ement : report of 3 c ases and a rev iew of t he lit erat ure. J Ur ol 1992;148(2 Pt 1):398–400. 289. Lerner SE, Blut e ML, Bergst ralh EJ, et al. Analy sis of risk f ac t ors f or progression in pat ient s w it h pat hologic ally c onf ined prost at e c anc ers af t er radic al ret ropubic prost at ec t omy . J Ur ol 1996; 156(1):137–143. 290. Lev ine E, Collins DL, Hort on WA, et al. CT sc reening of t he abdomen in v on Hippel- Lindau disease. Am J Roent genol 1982; 139(3):505–510. 291. Lev ine E, Grant ham JJ. Calc if ied renal st ones and c y st c alc if ic at ions in aut osomal dominant poly c y st ic kidney disease: c linic al and CT st udy in 84 pat ient s. Am J Roent genol 1992;159(1):77–81. 292. Lev ine E, Grant ham JJ. High- densit y renal c y st s in aut osomal dominant poly c y st ic kidney disease demonst rat ed by CT . Radiology 1985;154(2):477–482. 293. Lev ine E, Grant ham JJ, Slusher SL, et al. CT of ac quired c y st ic kidney disease and renal t umors in long- t erm dialy sis pat ient s. Am J Roent genol 1984;142(1):125–131.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2826

18 - The Kidney and Ureter 294. Lev ine E, Hunt rakoon M. Comput ed t omography of renal onc oc y t oma. Am J Roent genol 1983;141(4):741–746. 295. Lev ine E, Hunt rakoon M. Unilat eral renal c y st ic disease: CT f indings. J Com put Assist T om ogr 1989;13(2):273–276. 296. Lev ine E, Lee KR, Weigel JW, et al. Comput ed t omography in t he diagnosis of renal c arc inoma c omplic at ing Hippel- Lindau sy ndrome. Radiology 1979;130(3):703–706.

297. Lev ine E, Slusher SL, Grant ham JJ, et al. Nat ural hist ory of ac quired renal c y st ic disease in dialy sis pat ient s: a prospec t iv e longit udinal CT st udy . Am J Roent genol 1991;156(3):501–506. 298. Lev ine JA, Neit lic h J, Verga M, et al. Uret eral c alc uli in pat ient s w it h f lank pain: c orrelat ion of plain radiography w it h unenhanc ed helic al CT . Radiology 1997;204(1):27–31. 299. Lev ine LA, Gburek BM. Ac quired c y st ic disease and renal adenoc arc inoma f ollow ing renal t ransplant at ion. J Ur ol 1994;151(1): 129–132. 300. Ley endec ker JR, Dodd GD 3rd, Half f GA, et al. Sonographic ally observ ed ec hogenic response during int raoperat iv e radiof requenc y ablat ion of c irrhot ic liv ers: pat hologic c orrelat ion. Am J Roent genol 2002;178(5):1147–1151. 301. Lic ht MR, Nov ic k AC, T ubbs RR, et al. Renal onc oc y t oma: c linic al and biologic al c orrelat es. J Ur ol 1993;150(5 Pt 1):1380–1383. 302. Lingeman JE, Lif shit z DA, Ev an AP. Surgic al management of urinary lit hiasis. In: Walsh PC, Vaughan ED, ed. Cam pbell's ur ology , Vol 4. Philadelphia: Elsev ier Sc ienc e; 2002:3361–3451. 303. Liu J, F anning CV. Can renal onc oc y t omas be dist inguished f rom renal c ell c arc inoma on f ine- needle aspirat ion spec imens? A st udy of c onv ent ional smears in c onjunc t ion w it h anc illary st udies. Canc er 2001;93(6):390–397. 304. Llac h F , Papper S, Massry SG. T he c linic al spec t rum of renal v ein t hrombosis: ac ut e and c hronic . Am J Med 1980;69(6):819–827. 305. Lloy d- T homas HG, Balme RH, Key JJ. T ram- line c alc if ic at ion in renal c ort ic al nec rosis. Br Med J 1962;5282: 909–911. 306. Loc khart ME, Smit h JK, Kenney PJ, et al. Pseudot umorous renal inv olv ement of sarc oidosis. J Ur ol 2001;165(3):895. 307. Lonergan GJ, Ric e RR, Suarez ES. Aut osomal rec essiv e poly c y st ic kidney disease: radiologic - pat hologic c orrelat ion. Radiogr aphic s 2000;20(3):837–855.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2827

18 - The Kidney and Ureter 308. Lopez- Ben R, Smit h JK, Kew CE II, et al. F oc al post t ransplant at ion ly mphoprolif erat iv e disorder at t he renal allograf t hilum. Am J Roent genol 2000;175(5):1417–1422. 309. Lov e L, Lind JA Jr, Olson MC. Persist ent CT nephrogram: signif ic anc e in t he diagnosis of c ont rast nephropat hy . Radiology 1989; 172(1):125–129. 310. Lov e L, Y edlic ka J. Comput ed t omography of int ernally c alc if ied renal c y st s. Am J Roent genol 1985;145(6):1225–1227.

311. Low e LH, Isuani BH, Heller RM, et al. Pediat ric renal masses: Wilms t umor and bey ond. Radiogr aphic s 2000;20(6):1585–1603. 312. Madew ell JE, Goldman SM, Dav is CJ Jr, et al. Mult iloc ular c y st ic nephroma: a radiographic - pat hologic c orrelat ion of 58 pat ient s. Radiology 1983;146(2):309–321. 313. Madow it z JS, Sc hw eiger MJ. Sev ere anaphy lac t oid reac t ion t o radiographic c ont rast media. Rec urrenc es despit es premedic at ion w it h diphenhy dramine and prednisone, JAMA 1979;241(26): 2813–2815. 314. Maki DD, Birnbaum BA, Chakrabort y DP, et al. Renal c y st pseudoenhanc ement : beam- hardening ef f ec t s on CT numbers. Radiology 1999;213(2):468–472. 315. Mallouhi A, Rieger M, Czermak B, et al. Volume- rendered mult idet ec t or CT angiography : noninv asiv e f ollow - up of pat ient s t reat ed w it h renal art ery st ent s. Am J Roent genol 2003;180(1): 233–239. 316. Malt er IJ, St anley RJ. T he int rat horac ic kidney : w it h a rev iew of t he lit erat ure. J Ur ol 1972;107(4):538–541. 317. Mandel JS, Mc Laughlin JK, Sc hlehof er B, et al. Int ernat ional renal- c ell c anc er st udy . IV. Oc c upat ion. Int J Canc er 1995;61(5): 601–605. 318. Mann SJ. Capt opril renal sc ans f or det ec t ing renal art ery st enosis. Ar c h Int er n Med 2003;163(5):630; aut hor reply 630–631. 319. Marks WM, Korobkin M, Callen PW, et al. CT diagnosis of t umor t hrombosis of t he renal v ein and inf erior v ena c av a. Am J Roent genol 1978;131(5):843–846. 320. Marot t i M, Hric ak H, F rit zsc he P, et al. Complex and simple renal c y st s: c omparat iv e ev aluat ion w it h MR imaging. Radiology 1987;162(3):679–684. 321. Mart in J, Garc ia M, Duran A, et al. Renal v ein leiomy osarc oma: a c ase report and lit erat ure rev iew . Ur ol Radiol 1989;11(1):25–29. 322. Mart in RS 3rd, Meac ham PW, Dit esheim JA, et al. Renal art ery aneury sm: selec t iv e t reat ment f or hy pert ension and prev ent ion of rupt ure. J Vasc Sur g 1989;9(1):26–34.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2828

18 - The Kidney and Ureter 323. Mat son MA, Cohen EP. Ac quired c y st ic kidney disease: oc c urrenc e, prev alenc e, and renal c anc ers. Medic ine (Balt imore) 1990;69(4):217–226. P.1306

324. Mat sumot o ED, Wat umull L, Johnson DB, et al. T he radiographic ev olut ion of radio f requenc y ablat ed renal t umors. J Ur ol 2004;172(1):45–48. 325. May er DP, Baron RL, Pollac k HM. Inc rease in CT at t enuat ion v alues of parapelv ic renal c y st s af t er ret rograde py elography . Am J Roent genol 1982;139(5):991–993. 326. May es DC, F ec hner RE, Gillenw at er JY . Renal liposarc oma. Am J Sur gPat hol 1990;14(3):268–273. 327. Mc Clennan BL. Comput ed t omography in t he diagnosis and st aging of renal c ell c arc inoma. Sem in Ur ol 1985;3(2):111–131. 328. Mc Clennan BL, Balf e DM. Onc ologic imaging: kidney and uret er. Int er nat ional Jour nal of Radiat ion Onc ology , Biology , Phy sic s 1983;9(11):1683–1704. 329. Mc Coy JG, Honda H, Reznic ek M, et al. Comput erized t omography f or det ec t ion and st aging of loc alized and pat hologic ally def ined upper t rac t urot helial t umors. J Ur ol 1991;146(6): 1500–1503. 330. Mc Cullough PA, Woly n R, Roc her LL, et al. Ac ut e renal f ailure af t er c oronary int erv ent ion: inc idenc e, risk f ac t ors, and relat ionship t o mort alit y . Am J Med 1997;103(5):368–375. 331. Mc Donald JH, Mc Clellan DS. Crossed renal ec t opia. Am J Sur g 1957;93(6):995–1002. 332. Mc Gahan JP, Ric hards JR, Jones CD, et al. Use of ult rasonography in t he pat ient w it h ac ut e renal t rauma. J Ult r asound Med 1999;18(3):207–213. 333. Mc Gahan JP, Rose J, Coat es T L, et al. Use of ult rasonography in t he pat ient w it h ac ut e abdominal t rauma. J Ult r asound Med 1997;16(10):653–662. 334. Mc Millin KI, Gross BH. CT demonst rat ion of peripelv ic and periuret eral non- Hodgkin ly mphoma. Am J Roent genol 1985; 144(5):945–946. 335. Mc T av ish JD, Jinzaki M, Zou KH, et al. Mult i- det ec t or row CT Urography : c omparison of st rat egies f or depic t ing t he normal urinary c ollec t ing sy st em. Radiology 2002;225(3):783–790. 336. Meng MV, Mario LA, Mc Aninc h JW. Current t reat ment and out c omes of perinephric absc esses. J Ur ol 2002;168(4 Pt 1): 1337–1340.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2829

18 - The Kidney and Ureter 337. Merkus JWS, Zeebregt s CJAM, Hoit sma AJ, et al. High inc idenc e of art eriov enous f ist ula af t er biopsy of kidney allograf t s. Br J Sur g 1993;80(3):310–312. 338. Mert en GJ, Burgess WP, Gray LV, et al. Prev ent ion of c ont rast - induc ed nephropat hy w it h sodium bic arbonat e: a randomized c ont rolled t rial. JAMA 2004;291(19):2328–2334. 339. Mesrobian HG, Kelalis PP, Hrabov sky E, et al. Wilms t umor in horseshoe kidney s: a report f rom t he Nat ional Wilms T umor St udy . J Ur ol 1985;133(6):1002–1003. 340. Mic haeli J, Mogle P, Perlberg S, et al. Emphy semat ous py elonephrit is. J Ur ol 1984;131(2):203–208. 341. Middlet on WD, Pic us Daniel D, Marx MV, et al. Color Doppler sonography of hemodialy sis v asc ular ac c ess: c omparison w it h angiography . Am J Roent genol 1989;152:633–639. 342. Miller DL, Choy ke PL, Walt her MM, et al. Von Hippel- Lindau disease: inadequac y of angiography f or ident if ic at ion of renal c anc ers. Radiology 1991;179(3):833–836. 343. Miller F H, Parikh S, Gore RM, et al. Renal manif est at ions of AIDS. Radiogr aphic s 1993;13(3):587–596. 344. Mit nic k JS, Bosniak MA, Hilt on S, et al. Cy st ic renal disease in t uberous sc lerosis. Radiology 1983;147(1):85–87. 345. Mit sumori A, Y asui K, Akaki S, et al. Ev aluat ion of c rossing v essels in pat ient s w it h uret eropelv ic junc t ion obst ruc t ion by means of helic al CT . Radiogr aphic s 2000;20(5):1383–1393. 346. Mizobat a Y , Y okot a J, F ujimura I, et al. Suc c essf ul ev aluat ion of pseudoaneury sm f ormat ion af t er blunt renal injury w it h dual- phase c ont rast enhanc ed helic al CT . Am J Roent genol 2001; 177(1):136–138. 347. Moore EE, Shac kf ord SR, Pac ht er HL, et al. Organ injury sc aling: spleen, liv er, and kidney . J T r aum a 1989;29(12):1664–1666. 348. Morag B, Rubinst ein ZJ, Hert z M, et al. Comput ed t omography in t he diagnosis of renal parapelv ic c y st s. J Com put Assist T om ogr 1983;7(5):833–836. 349. Morales A, Wasan S, Bry niak S. Renal onc oc y t omas: c linic al, radiologic al and hist ologic al f eat ures. J Ur ol 1980;123(2):261–264. 350. Morgan DE, Nallamala LK, Kenney PJ, et al. CT c y st ography : radiographic and c linic al predic t ors of bladder rupt ure. Am J Roent genol 2000;174(1):89–95.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2830

18 - The Kidney and Ureter 351. Morgan WR, Ny berg LM Jr. Perinephric and int rarenal absc esses. Ur ology 1985;26(6):529–536. 352. Moset t i MA, Leonardou P, Mot ohara T , et al. Aut osomal dominant poly c y st ic kidney disease: MR imaging ev aluat ion using c urrent t ec hniques. J Magn Reson Im aging 2003;18(2):210–215. 353. Mourikis D, Chat ziioannou A, Ant oniou A, et al. Selec t iv e art erial embolizat ion in t he management of sy mpt omat ic renal angiomy olipomas. Eur J Radiol 1999;32(3):153–159. 354. Muller BT , Reiher L, Pf eif f er T , et al. Surgic al t reat ment of renal art ery dissec t ion in 25 pat ient s: indic at ions and result s. J Vasc Sur g 2003;37(4):761–768. 355. Murphy DM, Zinc ke H. T ransit ional c ell c arc inoma in t he horseshoe kidney : report of 3 c ases and rev iew of t he lit erat ure. Br J Ur ol 1982;54(5):484–485. 356. Murphy KP, Szopinski KT , Cohan RH, et al. Oc c urrenc e of adv erse reac t ions t o gadolinium- based c ont rast mat erial and management of pat ient s at inc reased risk: a surv ey of t he Americ an Soc iet y of Neuroradiology F ellow ship Direc t ors. Ac ad Radiol 1999;6(11):656–664. 357. My neni L, Hric ak H, Carroll PR. Magnet ic resonanc e imaging of renal c arc inoma w it h ext ension int o t he v ena c av a: st aging ac c urac y and rec ent adv anc es. Br J Ur ol 1991;68(6):571–578. 358. Nagashima Y , Inay ama Y , Kat o Y , et al. Pat hologic al and molec ular biologic al aspec t s of t he renal epit helial neoplasms, up- t o- dat e. Pat hol Int 2004; 54(6):377–386.

359. Narumi Y , Hric ak H, Prest i JC Jr, et al. MR imaging ev aluat ion of renal c ell c arc inoma. Abdom Im aging 1997;22(2):216–225. 360. Narumi Y , Sat o T , Hori S, et al. Squamous c ell c arc inoma of t he uroepit helium: CT ev aluat ion. Radiology 1989;173(3)853–856. 361. Nassir A, Jollimore J, Gupt a R, et al. Mult iloc ular c y st ic renal c ell c arc inoma: a series of 12 c ases and rev iew of t he lit erat ure. Ur ology 2002;60(3):421–427. 362. Nat ional Cent er f or Injury Prev ent ion and Cont rol. Injur y f ac t book 2001–2002. At lant a, GA: Cent ers f or Disease Cont rol and Prev ent ion; 2001. 363. Nat iv O, Reiman HM, Lieber MM, et al. T reat ment of primary squamous c ell c arc inoma of t he upper urinary t rac t . Canc er 1991;68(12):2575–2578. 364. Negru D, Ghiorghiu DC, Reut R, et al. Role of c omput erized t omography in t he diagnosis of t ransit ional c ell c arc inoma of t he upper urinary t rac t . Rev ist a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2831

18 - The Kidney and Ureter m edic o-c hir ur gic ala a Soc iet at ii de Medic i si Nat ur alist i din Iasi 2003;107(3):613–617. 365. Neumann HP, Bender BU, Berger DP, et al. Prev alenc e, morphology and biology of renal c ell c arc inoma in v on Hippel- Lindau disease c ompared t o sporadic renal c ell c arc inoma. J Ur ol 1998;160(4):1248–1254. 366. Neuzillet Y , Lec hev allier E, Andre M, et al. Ac c urac y and c linic al role of f ine needle perc ut aneous biopsy w it h c omput erized t omography guidanc e of small (less t han 4.0 c m) renal masses. J Ur ol 2004;171(5):1802–1805. 367. Nev ille H, Rit c hey ML, Shamberger RC, et al. T he oc c urrenc e of Wilms t umor in horseshoe kidney s: a report f rom t he Nat ional Wilms T umor St udy Group (NWT SG). J Pediat r Sur g 2002; 37(8):1134–1137. 368. Niall O, Russell J, Mac Gregor R, et al. A c omparison of nonc ont rast c omput erized t omography w it h exc ret ory urography in t he assessment of ac ut e f lank pain. J Ur ol 1999;161(2):534–537. 369. Nic holson DA. Case report : replac ement lipomat osis of t he kidney —unusual CT f eat ures. Clin Radiol 1992;45(1):42–43. 370. Nic olaisen GS, Mc Aninc h JW, Marshall GA, et al. Renal t rauma: reev aluat ion of t he indic at ions f or radiographic assessment . J Ur ol 1985;133(2):183–187. 371. Nissenkorn I, Bernheim J. Mult ic ent ric it y in renal c ell c arc inoma. J Ur ol 1995;153(3 Pt 1):620–622. 372. Nolt e- Ernst ing CC, Buc ker A, Adam GB, et al. Gadolinium- enhanc ed exc ret ory MR urography af t er low - dose diuret ic injec t ion: c omparison w it h c onv ent ional exc ret ory urography . Radiology 1998;209(1):147–157. 373. Nov ic k AC. Laparosc opic and part ial nephrec t omy . Clin Canc er Res 2004;10(18 Pt 2):6322S–6327S. 374. Nov ic k AC. Nephron- sparing surgery f or renal c ell c arc inoma. Annu Rev Med 2002;53:393–407.

375. Ny man U, Oldbring J, Aspelin P. CT of c arc inoma of t he renal pelv is. Ac t a Radiol 1992;33(1):31–38. P.1307 376. Oest erling JE, F ishman EK, Goldman SM, et al. T he management of renal angiomy olipoma. I 1986;135(6):1121–1124. 377. Olazabal A, Velasc o M, Mart inez A, et al. Emphy semat ous py elonephrit is. Ur ology 1987;29(1):95–98.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2832

18 - The Kidney and Ureter

378. Olc ot t EW, Sommer F G, Napel S. Ac c urac y of det ec t ion and measurement of renal c alc uli: in v it ro c omparison of t hree- dimensional spiral CT , radiography , and nephrot omography . Radiology 1997;204(1):19–25. 379. Ozen H, Colow ic k A, F reiha F S. Inc ident ally disc ov ered solid renal masses: w hat are t hey ? Br J Ur ol 1993;72(3):274–276. 380. Pagani JJ. Solid renal mass in t he c anc er pat ient : sec ond primary renal c ell c arc inoma v ersus renal met ast asis. J Com put Assist T om ogr 1983;7(3):444–448. 381. Paiv ansalo M, Lahde S, Hy v arinen S, et al. Renal angiomy olipoma. Ult rasonographic , CT , angiographic , and hist ologic c orrelat ion. Ac t a Radiol 1991;32(3):239–243. 382. Pardalidis NP, Papat soris AG, Kosmaoglou EV. Endosc opic and laparosc opic t reat ment of uret eropelv ic junc t ion obst ruc t ion. J Ur ol 2002;168(5):1937–1940. 383. Parf rey PS, Bear JC, Morgan J, et al. T he diagnosis and prognosis of aut osomal dominant poly c y st ic kidney disease. N Engl J Med 1990;323(16):1085–1090. 384. Parient y RA, Duc ellier R, Pradel J, et al. Diagnost ic v alue of CT numbers in pelv oc aly c eal f illing def ec t s. Radiology 1982;145(3): 743–747. 385. Parient y RA, Pradel J, Imbert MC, et al. Comput ed t omography of mult iloc ular c y st ic nephroma. Radiology 1981;140(1):135–139. 386. Parient y RA, Pradel J, Parient y I. Cy st ic renal c anc ers: CT c harac t erist ic s. Radiology 1985;157(3):741–744. 387. Parker MD, Clark RL. Ev olv ing c onc ept s in t he diagnosis of xant hogranulomat ous py elonephrit is. Ur ol Radiol 1989;11(1):7–15. 388. Pasc al RR. Renal manif est at ions of ext rarenal neoplasms. Hum Pat hol 1980;11(1):7–17. 389. Perez- Ordonez B, Hamed G, Campbell S, et al. Renal onc oc y t oma: a c linic opat hologic st udy of 70 c ases. Am J Sur g Pat hol 1997;21(8):871–883. 390. Pey romaure M, T hiounn N, Sc ot t e F , et al. Collec t ing duc t c arc inoma of t h e kidney : a c linic opat hologic al st udy of 9 c ases. J Ur ol 2003;170(4 Pt 1):1138–1140. 391. Pf eif f er T , Reiher L, Grabit z K, et al. Rec onst ruc t ion f or renal art ery aneury sm: operat iv e t ec hniques and long- t erm result s. J Vasc Sur g 2003;37(2):293–300.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2833

18 - The Kidney and Ureter 392. Pic khardt PJ, Lonergan GJ, Dav is CJ Jr, et al. F rom t he arc hiv es of t he

AF IP. Inf ilt rat iv e renal lesions: radiologic - pat hologic c orrelat ion. Armed F orc es Inst it ut e of Pat hology . Radiogr aphic s 2000; 20(1):215–243. 393. Pic khardt PJ, Siegel CL, Mc Larney JK. Collec t ing duc t c arc inoma of t he kidney : are imaging f indings suggest iv e of t he diagnosis. Am J Roent genol 2001;176(3):627–633. 394. Pillay K, Lazarus J, Wainw right HC. Assoc iat ion of angiomy olipoma and onc oc y t oma of t he kidney : a c ase report and rev iew of t he lit erat ure. J Clin Pat hol 2003;56(7):544–547. 395. Pit t s WR Jr, Muec ke EC. Horseshoe kidney s: a 40- y ear experienc e. J Ur ol 1975;113(6)743–746. 396. Planz B, George R, Adam G, et al. Comput ed t omography f or det ec t ion and st aging of t ransit ional c ell c arc inoma of t he upper urinary t rac t . Eur Ur ol 1995;27(2):146–150. 397. Pode D, Meret ik S, Shapiro A, et al. Diagnosis and management of renal angiomy olipoma. Ur ology 1985;25(5):461–467. 398. Ponholzer A, Reit er WJ, Maier U. Organ sparing surgery f or giant bilat eral renal onc oc y t oma. J Ur ol 2002;168(6):2531–2532. 399. Pov ey S, Burley MW, At t w ood J, et al. T w o loc i f or t uberous sc lerosis: one on 9q34 and one on 16p13. Ann Hum Genet 1994;58 (Pt 2):107–127. 400. Pozniak MA, Balison DJ, Lee F T Jr, et al. CT angiography of pot ent ial renal t ransplant donors. Radiogr aphic s 1998;18(3): 565–587. 401. Pozniak MA, Nakada SY . T hree- dimensional c omput ed t omographic angiography of a horseshoe kidney w it h uret eropelv ic junc t ion obst ruc t ion. Ur ology 1997;49(2):267–268. 402. Preda A, Van Dijk LC, Van Oost aijen JA, et al. Complic at ion rat e and diagnost ic y ield of 515 c onsec ut iv e ult rasound- guided biopsies of renal allograf t s and nat iv e kidney s using a 14- gauge Biopt y gun. Eur Radiol 2003;13(3):527–530. 403. Preminger GM, View eg J, Leder RA, et al. Urolit hiasis: det ec t ion and management w it h unenhanc ed spiral CT —- a urologic perspec t iv e. Radiology 1998;207(2):308–309. 404. Premkumar A, Lat t imer J, New house JH. CT and sonography of adv anc ed urinary t rac t t uberc ulosis. Am J Roent genol 1987; 148(1):65–69. 405. Pret orius ES, Siegelman ES, Ramc handani P, et al. Renal neoplasms amenable t o part ial nephrec t omy : MR imaging. Radiology 1999;212(1):28–34.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2834

18 - The Kidney and Ureter 406. Quinn MJ, Hart man DS, F riedman AC, et al. Renal onc oc y t oma: new observ at ions. Radiology 1984;153(1):49–53. 407. Raabe NK, F ossa SD, Bjerkehagen B. Carc inoma of t he renal pelv is. Experienc e of 80 c ases. Sc and J Ur ol Nephr ol 1992;26(4):357–361. 408. Rabah D, Soderdahl DW, Mc Adams PD, et al. Uret eropelv ic junc t ion obst ruc t ion: does CT angiography allow bet t er selec t ion of t herapeut ic modalit ies and bet t er pat ient out c ome? J Endour ol 2004;18(5):427–430. 409. Radermac her J, Chav an A, Blec k J, et al. Use of Doppler ult rasonography t o predic t t he out c ome of t herapy f or renal- art ery st enosis. N Engl J Med 2001;344(6):410–417. 410. Rahmouni A, Mat hieu D, Berger JF , et al. F ast magnet ic resonanc e imaging in t he ev aluat ion of t umoral obst ruc t ions of t he inf erior v ena c av a. J Ur ol 1992;148(1):14–17. 411. Raj GV, Auge BK, Weizer AZ, et al. Perc ut aneous management of c alc uli w it hin horseshoe kidney s. J Ur ol 2003;170(1):48–51. 412. Ramani AP, Desai MM, St einberg AP, et al. Complic at ions of laparosc opic part ial nephrec t omy in 200 c ases. J Ur ol 2005; 173(1):42–47. 413. Rapt opoulos V, Kleinman PK, Marks S Jr, et al. Renal f asc ial pat hw ay : post erior ext ension of panc reat ic ef f usions w it hin t he ant erior pararenal spac e. Radiology 1986;158(2):367–374.

414. Raza SA, Chught ai AR, Wahba M, et al. Mult islic e CT angiography in renal art ery st ent ev aluat ion: prospec t iv e c omparison w it h int ra- art erial digit al subt rac t ion angiography . Car diov asc Int er v ent Radiol 2004;27(1):9–15. 415. Reiher L, Grabit z K, Sandmann W. Rec onst ruc t ion f or renal art ery aneury sm and it s ef f ec t on hy pert ension. Eur J Vasc Endov asc Sur g 2000;20(5):454–456. 416. Reiman T A, Siegel MJ, Shac kelf ord GD. Wilms t umor in c hildren: abdominal CT and US ev aluat ion. Radiology 1986;160(2): 501–505. 417. Rendon RA, Kac hura JR, Sw eet JM, et al. T he unc ert aint y of radio f requenc y t reat ment of renal c ell c arc inoma: f indings at immediat e and delay ed nephrec t omy . J Ur ol 2002;167(4):1587–1592. 418. Reznek RH, Moot oosamy I, Webb JA, et al. CT in renal and perirenal ly mphoma: a f urt her look. Clin Radiol 1990;42(4):233–238. 419. Ric hie JP, Garnic k MB, Selt zer S, et al. Comput erized t omography sc an f or diagnosis and st aging of renal c ell c arc inoma. J Ur ol 1983;129(6):1114–1116.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2835

18 - The Kidney and Ureter 420. Ric ht er F , Kasabian NG, Irw in RJ Jr, et al. Ac c urac y of diagnosis by guided biopsy of renal mass lesions c lassif ied indet erminat e by imaging st udies. Ur ology 2000;55(3):348–352.

421. Rigsby CM, Rosenf ield AT , Glic kman MG, et al. Hemorrhagic f oc al bac t erial nephrit is: f indings on gray - sc ale sonography and CT . Am J Roent genol 1986;146(6):1173–1177. 422. Robson CJ, Churc hill BM, Anderson W. T he result s of radic al nephrec t omy f or renal c ell c arc inoma. J Ur ol 1969;101(3): 297–301. 423. Rominger MB, Kenney PJ, Morgan DE, et al. Gadolinium- enhanc ed MR imaging of renal masses. Radiogr aphic s 1992:12(6): 1097–1116. 424. Romis L, Cindolo L, Pat ard JJ, et al. F requenc y , c linic al present at ion and ev olut ion of renal onc oc y t omas: mult ic ent ric experienc e f rom a European dat abase. Eur Radiol 2004;45(1):53–57. 425. Rosenberg ER, Korobkin M, F ost er W, et al. T he signif ic anc e of sept at ions in a renal c y st . Am J Roent genol 1985;144(3):593–595. 426. Rosenberg SA, Diamond HD, Jaslow it z B, et al. Ly mphosarc oma: a rev iew of 1269 c ases. Medic ine 1961;40:31–84. 427. Rosi P, Selli C, Carini M, et al. Xant hogranulomat ous py elonephrit is: c linic al experienc e w it h 62 c ases. Eur Ur ol 1986; 12(2):96–100. 428. Roubidoux MA. MR imaging of hemorrhage and iron deposit ion in t he kidney . Radiogr aphic s 1994;14(5):1033–1044. P.1308 429. Roubidoux MA, Dunnic k NR, Sost man HD, et al. Renal c arc inoma: det ec t ion of v enous ext ension w it h gradient - ec ho MR imaging. Radiology 1992;182(1):269–272. 430. Rouv iere O, Ly onnet D, Berger P, et al. Uret eropelv ic junc t ion obst ruc t ion: use of helic al CT f or preoperat iv e assessment —c omparison w it h int raart erial angiography . Radiology 1999; 213(3):668–673. 431. Roy C, Pf leger DD, T uc hmann CM, et al. Emphy semat ous py elit is: f indings in f iv e pat ient s. Radiology 2001;218(3):647–650. 432. Roy - Choudhury SH, Cast JE, Cooksey G, et al. Early experienc e w it h perc ut aneous radiof requenc y ablat ion of small solid renal masses. Am J Roent genol 2003;180(4):1055- 1061. 433. Rubin BE. Comput ed t omography in t he ev aluat ion of renal ly mphoma. J Com put Assist T om ogr 1979;3(6):759–764. 434. Rubin GD. Helic al CT of pot ent ial liv ing renal donors: t ow ard a great er underst anding. Radiogr aphic s 1998;18(3):601–604.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2836

18 - The Kidney and Ureter 435. Rubinst ein ZJ, Hert z M, Shahin N, et al. Crossed renal ec t opia: angiographic f indings in six c ases. Am J Roent genol 1976;126(5): 1035–1038.

436. Rubio Briones J, Regalado Pareja R, Sanc hez Mart in F , et al. Inc idenc e of t umoural pat hology in horseshoe kidney s. Eur Radiol 1998;33(2):175–179. 437. Rumanc ik WM, Bosniak MA, Rosen RJ, et al. At y pic al renal and pararenal hamart omas assoc iat ed w it h ly mphangiomy omat osis. Am J Roent genol 1984;142(5):971–972. 438. Russo P. Renal c ell c arc inoma: present at ion, st aging, and surgic al t reat ment . Sem in Onc ol 2000;27(2):160–176. 439. Ry bic ki F J, Shu KM, Cibas ES, et al. Perc ut aneous biopsy of renal masses: sensit iv it y and negat iv e predic t iv e v alue st rat if ied by c linic al set t ing and size of masses. Am J Roent genol 2003;180(5): 1281–1287. 440. Sait o S. Primary renal ly mphoma. Case report and rev iew of t he lit erat ure. Ur ol Int 1996;56(3):192–195. 441. Salem Y H, Miller HC. Ly mphoma of genit ourinary t rac t . J Ur ol 1994;151(5):1162–1170. 442. Sc hrier RW, Belz MM, Johnson AM, et al. Repeat imaging f or int rac ranial aneury sms in pat ient s w it h aut osomal dominant poly c y st ic kidney disease w it h init ially negat iv e st udies: a prospec t iv e t en- y ear f ollow - up. J Am Soc Nephr ol 2004;15(4):1023–1028. 443. Sc hubert RA, Soldner J, St einer T , et al. Bilat eral renal c ell c arc inoma in a horseshoe kidney : preoperat iv e assessment w it h MRI and digit al subt rac t ion angiography . Eur Radiol 1998;8(9): 1694–1697. 444. Sc hw art z BF , St oller ML. Complic at ions of ret rograde balloon c aut ery endopy elot omy . J Ur ol 1999;162(5):1594–1598. 445. Sc olieri MJ, Paik ML, Brow n SL, et al. Limit at ions of c omput ed t omography in t he preoperat iv e st aging of upper t rac t urot helial c arc inoma. Ur ology 2000;56(6):930–934. 446. Segal AJ, Spit zer RM. Pseudo t hic k- w alled renal c y st by CT . Am J Roent genol 1979;132(5):827–828. 447. Segaw a N, Azuma H, Iw amot o Y , et al. Expandable met allic st ent plac ement f or nut c rac ker phenomenon. Ur ology 1999;53(3): 631–633. 448. Segura JW, Kelalis PP, Burke EC. Horseshoe kidney in c hildren. J Ur ol 1972;108(2):333–336.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2837

18 - The Kidney and Ureter 449. Semelka RC, Hric ak H, St ev ens SK, et al. Combined gadolinium- enhanc ed and f at - sat urat ion MR imaging of renal masses. Radiology 1991;178(3): 803–809. 450. Semelka RC, Hric ak H, T omei E, et al. Obst ruc t iv e nephropat hy : ev aluat ion w it h dy namic Gd- DT PA- enhanc ed MR imaging. Radiology 1990;175(3):797–803. 451. Semelka RC, Kelekis NL, Burdeny DA, et al. Renal ly mphoma: demonst rat ion by MR imaging. Am J Roent genol 1996;166(4): 823–827. 452. Semelka RC, Shoenut JP, Kroeker MA, et al. Renal lesions: c ont rolled c omparison bet w een CT and 1.5- T MR imaging w it h nonenhanc ed and gadolinium- enhanc ed f at - suppressed spin- ec ho and breat h- hold F LASH t ec hniques. Radiology 1992;182(2): 425–430. 453. Shanmuganat han K, Mirv is SE, Sov er ER. Value of c ont rast - enhanc ed CT in det ec t ing ac t iv e hemorrhage in pat ient s w it h blunt abdominal or pelv ic t rauma. Am J Roent genol 1993;161(1):65–69. 454. Sheaf or DH, Hert zberg BS, F reed KS, et al. Nonenhanc ed helic al CT and US in t he emergenc y ev aluat ion of pat ient s w it h renal c olic : prospec t iv e c omparison. Radiology 2000;217(3):792–797. 455. Sheinf eld J, Ert urk E, Spat aro RF , et al. Perinephric absc ess: c urrent c onc ept s. J Ur ol 1987;137(2)(F ebruary ):191–194. 456. Shemesh J, Koren- Morag N, Apt er S, et al. Ac c elerat ed progression of c oronary c alc if ic at ion: f our- y ear f ollow - up in pat ient s w it h st able c oronary art ery disease. Radiology 2004;233(1):201–209. 457. Shet h S, F ishman EK. Mult i- det ec t or row CT of t he kidney s and urinary t rac t : t ec hniques and applic at ions in t he diagnosis of benign diseases. Radiogr aphic s 2004;24(2):e20. 458. Shet h S, Sc at arige JC, Hort on KM, et al. Current c onc ept s in t he diagnosis and management of renal c ell c arc inoma: role of mult idet ec t or CT and t hree- dimensional CT . Radiogr aphic s 2001;21: S237–S254. 459. Shinglet on WB, Sew ell PE Jr. Perc ut aneous renal c ry oablat ion of renal t umors in pat ient s w it h v on Hippel- Lindau disease. J Ur ol 2002;167(3):1268–1270.

460. Shirkhoda A. CT f indings in hepat osplenic and renal c andidiasis. J Com put Assist T om ogr 1987;11(5):795–798. 461. Shirkhoda A, Lew is E. Renal sarc oma and sarc omat oid renal c ell c arc inoma: CT and angiographic f eat ures. Radiology 1987; 162(2):353–357.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2838

18 - The Kidney and Ureter

462. Shokeir AA, El- Azab M, Mohsen T , et al. Emphy semat ous py elonephrit is: a 15- y ear experienc e w it h 20 c ases. Ur ology 1997;49(3):343–346. 463. Shokeir AA, el- Diast y T A, Ghoneim MA. T he nut c rac ker sy ndrome: new met hods of diagnosis and t reat ment . Br J Ur ol 1994;74(2):139–143. 464. Si- Hoe CK, T hng CH, Chee SG, et al. Abdominal c omput ed t omography in sy st emic lupus ery t hemat osus. Clin Radiol 1997; 52(4):284–289. 465. Sidhu R, Gupt a R, Dabra A, et al. Int rat horac ic kidney in an adult . Ur ol Int 2001;66(3):174–175. 466. Siegel CL, Mc Dougall EM, Middlet on WD, et al. Preoperat iv e assessment of uret eropelv ic junc t ion obst ruc t ion w it h endoluminal sonography and helic al CT . Am J Roent genol 1997;168(3): 623–626. 467. Sise C, Kusaka M, Wet zel LH, et al. Volumet ric det erminat ion of progression in aut osomal dominant poly c y st ic kidney disease by c omput ed t omography . Kidney Int 2000;58(6):2492–2501. 468. Sly w ot zky C, May a M. Needle t rac t seeding of t ransit ional c ell c arc inoma f ollow ing f ine- needle aspirat ion of a renal mass. Abdom Im aging 1994;19(2):174–176. 469. Sly w ot zky CM, Bosniak MA. Loc alized c y st ic disease of t he kidney . Am J Roent genol 2001;176(4):843–849. 470. Smit h BM, Holc omb GW 3rd, Ric hie RE, et al. Renal art ery dissec t ion. Ann Sur g 1984;200(2):134–146. 471. Smit h PA, Rat ner LE, Ly nc h F C, et al. Role of CT angiography in t he preoperat iv e ev aluat ion f or laparosc opic nephrec t omy . Radiogr aphic s 1998;18(3):589–601. 472. Smit h RC, Rosenf ield AT , Choe KA, et al. Ac ut e f lank pain: c omparison of non- c ont rast - enhanc ed CT and int rav enous urography . Radiology 1995;194(3):789–794. 473. Smit h RC, Verga M, Dalry mple N, et al. Ac ut e uret eral obst ruc t ion: v alue of sec ondary signs of helic al unenhanc ed CT . Am J Roent genol 1996;167(5):1109–1113. 474. Smit h RC, Verga M, Mc Cart hy S, et al. Diagnosis of ac ut e f lank pain: v alue of unenhanc ed helic al CT . Am J Roent genol 1996; 166(1):97–101. 475. Song JH, Cronan JJ. Perc ut aneous biopsy in dif f use renal disease: c omparison of 18- and 14- gauge aut omat ed biopsy dev ic es. J Vasc Int er v ent Radiol 1998;9(4):651–655. 476. Soulen MC, F ishman EK, Goldman SM. Sequelae of ac ut e renal inf ec t ions: CT ev aluat ion. Radiology 1989;173(2):423–426.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2839

18 - The Kidney and Ureter

477. Soulen MC, F ishman EK, Goldman SM, et al. Bac t erial renal inf ec t ion: role of CT . Radiology 1989;171(3):703–707. 478. Sriniv as V, Sogani PC, Hajdu SI, et al. Sarc omas of t he kidney . J Ur ol 1984;132(1):13–16. 479. St abile Ianora AA, Sc ardapane A, Chiumarullo L, et al. Congenit al st enosis of uret eropelv ic junc t ion: assessment w it h mult islic e CT . Radiol Med (T orino) 2003;105(4):315–325. 480. St ables DP, F ouc he RF , de Villiers v an Niekerk JP, et al. T raumat ic renal art ery oc c lusion: 21 c ases. I 1976;115(3):229–233. 481. St allone G, Inf ant e B, Manno C, et al. Primary renal ly mphoma does exist : c ase report and rev iew of t he lit erat ure. J Nephr ol 2000;13(5):367–372. P.1309 482. St eele JR, Sones PJ, Hef f ner LT Jr. T he det ec t ion of inf erior v ena c av al t hrombosis w it h c omput ed t omography . Radiology 1978; 128(2):385–386. 483. St einer MS, Goldman SM, F ishman EK, et al. T he nat ural hist ory of renal angiomy olipoma. J Ur ol 1993;150(6):1782–1786. 484. St oll C, Alembik Y , Dot t B, et al. Prenat al det ec t ion of int ernal urinary sy st em's anomalies. A regist ry - based st udy . Eur J Epidem iol 1995;11(3):283–290. 485. St rait on JA, Mc Millan A, Morley P. Ult rasound in suspec t ed obst ruc t ion c omplic at ing renal t ransplant at ion. Br J Radiol 1989; 62(741):803–806. 486. St randness DE Jr. Duplex imaging f or t he det ec t ion of renal art ery st enosis. Am J Kidney Dis 1994;24(4):674–678. 487. St reem SB, Geisinger MA. Prev ent ion and management of hemorrhage assoc iat ed w it h c aut ery w ire balloon inc ision of uret eropelv ic junc t ion obst ruc t ion. J Ur ol 1995;153:1904–1906. 488. St rif e JL, Souza AS, Kirks DR, et al. Mult ic y st ic dy splast ic kidney in c hildren: US f ollow - up. Radiology 1993;186(3):785–788. 489. St uder UE, Sc herz S, Sc heidegger J, et al. Enlargement of regional ly mph nodes in renal c ell c arc inoma is of t en not due t o met ast ases. J Ur ol 1990;144(2 Pt 1):243–245. 490. Subramany am BR, Bosniak MA, Horii SC, et al. Replac ement lipomat osis of t he kidney : diagnosis by c omput ed t omography and sonography . Radiology 1983;148(3):791–792. 491. Sugay a K, Ogaw a Y , Hat ano T , et al. Compensat ory renal hy pert rophy and c hanges of renal f unc t ion f ollow ing nephrec t omy . Hiny okika Kiy o 2000;46(4):235–240.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2840

18 - The Kidney and Ureter 492. Sumi Y , Ozaki Y , Shindoh N, et al. Gallium- 67 upt ake in Bellini duc t c arc inoma of t he kidney . Ann Nuc l Med 1999;13(2): 117–120.

493. Sussman S, Coc hran ST , Pagani JJ, et al. Hy perdense renal masses: a CT manif est at ion of hemorrhagic renal c y st s. Radiology 1984;150(1):207–211. 494. Sussman SK, Gallmann WH, Cohan RH, et al. CT f indings in xant hogranulomat ous py elonephrit is w it h c oexist ent renoc olic f ist ula. J Com put Assist T om ogr 1987;11(6):1088–1090. 495. Sussman SK, Goldberg RP, Grisc om NT . Milk- of - c alc ium hy dronephrosis in pat ient s w it h paraplegia and urinary - ent eric div ersion: CT demonst rat ion. J Com put Assist T om ogr 1986;10(2): 257–259. 496. Sv ane S. T umor t hrombus of t he inf erior v ena c av a result ing f rom renal c arc inoma. A report on 12 aut opsied c ases. Sc and J Ur ol Nephr ol 1969;3(3):245–256. 497. Sv ed PD, Gomez P, Nieder AM, et al. Upper t rac t t umour af t er radic al c y st ec t omy f or t ransit ional c ell c arc inoma of t he bladder: inc idenc e and risk f ac t ors. BJU Int er nat ional 2004;94(6): 785–789. 498. Sw art z MA, Kart h J, Sc hneider DT , et al. Renal medullary c arc inoma: c linic al, pat hologic , immunohist oc hemic al, and genet ic analy sis w it h pat hogenet ic implic at ions. Ur ology 2002;60(6): 1083–1089. 499. Szolar DH, Kammerhuber F , Alt ziebler S, et al. Mult iphasic helic al CT of t he kidney : inc reased c onspic uit y f or det ec t ion and c harac t erizat ion of small (2,000 pg/mL) (16). How ev er, bioc hemic al t est s are expensiv e, t ime c onsuming, and f raught w it h dif f ic ult y bec ause suc h f ac t ors as episodic c at ec holamine produc t ion, c onc urrent medic at ion, st ress, inadequat e urine c ollec t ion f or 24- hour samples, and ot her f ac t ors c an c ont ribut e t o bot h f alse–posit iv e and f alse–negat iv e result s f or ev ery know n t est . Det ec t ion and loc alizat ion are import ant bec ause

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2881

19 - The Adrenal Glands surgic al resec t ion is c urat iv e, and bec ause t here is no ef f ec t iv e medic al t herapy . Unrec ognized and unt reat ed pheoc hromoc y t oma of t en result s in unt imely deat h result ing f rom c omplic at ions of surgery or ow ing t o long- t erm c omplic at ions suc h as my oc ardial inf arc t ion or c erebral and renal v asc ular disease (142). T hus, imaging c an play an import ant role in ev aluat ion of pat ient s suspec t ed of pheoc hromoc y t oma.

F igure 19- 28 Adrenal c arc inoma. A: T his pat ient present ed w it h abdominal pain but w as f ound t o be hy pert ensiv e. Unenhanc ed c omput ed t omography rev eals 5 (6 c m lef t adrenal mass [ar r ow ], at t enuat ion 21 HU. B: Enhanc ed sc an show s moderat e het erogeneous enhanc ement . C : Perc ut aneous biopsy w as perf ormed, but report w as “ Adrenal c ort ic al neoplasm, nonspec if ic .” T he mass w as resec t ed w it h f inal pat hology adrenal c arc inoma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2882

19 - The Adrenal Glands

F igure 19- 29 Nonf unc t ioning adrenal c arc inoma. Pat ient w as ref erred f or w hat w as t hought on out side c omput ed t omography t o be a renal mass; she had no endoc rine signs or sy mpt oms. A: longit udinal relaxat ion t ime (T 1)w eight ed gradient ref oc used ec ho sequenc e show s an irregularly shaped slight ly het erogeneous 4.5 Г— 5.0 c m right adrenal mass (open ar r ow ); not e t he normal lef t adrenal (ar r ow ). B: Coronal breat h- hold t ransv erse relaxat ion t ime (T 2)- w eight ed (HAST E) image show s t he het erogeneously hy perint ense mass (ar r ow ) indent s but is separat e f rom t he right kidney . C : T he suprarenal origin is v ery c lear on c oronal breat hhold T 1 (ar r ow ). D: F ollow ing int rav enous administ rat ion of gadolinium diet hy lene- t riamine pent a- ac et ic ac id (150/6/70 degrees 7), t here is het erogeneous enhanc ement .

Pheoc hromoc y t oma is f ound in less t han 1% of t he hy pert ensiv e populat ion and in 0.3% of aut opsies (142). Clinic al signs suggest iv e of t he diagnosis inc lude labile hy pert ension, inc luding paroxy sms of hy pert ension and t ac hy c ardia, headac he, palpit at ion, diaphoresis, pallor, and w eight loss (142). T here is an inc reased likelihood of pheoc hromoc y t oma in pat ient s w it h neurof ibromat osis, v on Hippel- Lindau disease, and mult iple endoc rine neoplasia (MEN) sy ndromes (50% in MEN 2 and 90% in MEN 2b). In suc h sy ndromes, and in c hildren, mult iple or bilat eral c ases are more likely . In MEN 2b, bilat eral

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2883

19 - The Adrenal Glands t umors are so c ommon t hat bilat eral adrenalec t omy is rec ommended bec ause lesions may rec ur af t er unilat eral surgery (16,73) (F ig. 19- 31).

F igure 19- 30 Pheoc hromoc y t oma. T his pat ient dev eloped malignant hy pert ension during a surgic al proc edure, st imulat ing ev aluat ion. A: Prec ont rast c omput ed t omography show s a 5 Г— 6 c m lef t adrenal mass (ar r ow ), at t enuat ion is t hat of sof t t issue, 27 HU. B: T he mass show s het erogeneous enhanc ement af t er int rav enous c ont rast .

P.1333 Alt hough 90% of pheoc hromoc y t omas arise in t he adrenal, up t o 10% are ext ra- adrenal (F igs. 19- 31, 19- 32, 9- 33), w it h many suc h lesions (7%) in t he inf rarenal port ion of t he ret roperit oneum, arising in t he organ of Zuc kerkandl (63) (see F ig. 19- 33). Paragangliomas c an be single or mult iple, and t hey may hav e great er malignant pot ent ial (63). Paragangliomas also c an be f ound in t he nec k, t he mediast inum, and t he w all of t he urinary bladder. T he lat t er pat ient s c an present w it h a dist inc t c linic al pic t ure of headac he, diaphoresis, and hy pert ension relat ed t o a dist ended bladder, or t o urinat ion. Pheoc hromoc y t omas are usually larger t han 3 c m at present at ion and inv ariably should be ident if ied by CT (173). If small, t he t umors are round and hav e homogeneous sof t t issue–at t enuat ion v alues (see F igs. 19- 30 and 1934). Bec ause pheoc hromoc y t omas are hy perv asc ular neoplasms, t hey hav e a propensit y t o undergo hemorrhagic nec rosis ev en w hen benign, ac c ount ing f or t he c ent ral low at t enuat ion seen in large neoplasms (F igs. 19- 35 and 19- 36). Cent ral nec rosis may be so ext ensiv e as t o simulat e a c y st (20,42). Calc if ic at ion is unc ommon; w hen present , it may hav e an eggshell pat t ern (32,59,78). Af t er int rav enous administ rat ion of iodinat ed c ont rast medium, pheoc hromoc y t omas exhibit het erogeneous enhanc ement , a pat t ern

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2884

19 - The Adrenal Glands indist inguishable f rom t hat of a malignant adrenal neoplasm. Correlat ion w it h bioc hemic al f unc t ion is required t o est ablish t he c orrec t diagnosis.

F igure 19- 31 Mult iple pheoc hromoc y t omas in mult iple endoc rine neoplasia 2b. A: Comput ed t omography show s bilat eral het erogeneous adrenal t umors (ar r ow s). B: At a more inf erior lev el, addit ional bilat eral adrenal t umors (ar r ow s) are seen, as w ell as an ext ra- adrenal lesion (c ur v ed ar r ow ).

Bec ause pheoc hromoc y t omas are large, t hey c an be det ec t ed ev en w it h unenhanc ed CT (133). Some c onc ern has been raised about t he use of int rav enous c ont rast in pat ient s w it h pheoc hromoc y t oma. Plasma c at ec holamine lev els c an be raised by int rav enous injec t ion of iodinat ed P.1334 c ont rast medium, but sy mpt omat ic blood pressure elev at ions do not usually result (133). Only if a pat ient has know n hy pert ensiv e episodes and has not had adequat e pharmac ologic adrenergic bloc kade is it nec essary t o av oid c ont rast . Cont rast is espec ially usef ul f or det ec t ion of ext ra- adrenal lesions. Alt hough paragangliomas c an usually be ident if ied on CT (see F ig. 19- 32), t hey hav e a nonspec if ic appearanc e. T he CT f eat ures of malignant paragangliomas in part ic ular ov erlap w it h t hose of ot her ret roperit oneal malignanc ies (63). Radionuc lide met aiodobenzy lguanidine (MIBG) sc int igraphy c an be usef ul t o doc ument w het her a ret roperit oneal mass is in f ac t a paraganglioma (63,131). Anot her met hod used in c ases of a suspec t ed paraganglioma is dosage of c at ec holamines. T he presenc e of high lev els of norepinephrine alone indic at es t hat t he suspec t ed mass is more likely a paraganglioma. How ev er, t he presenc e of bot h epinephrine and norepinephrine is highly suggest iv e of a pheoc hromoc y t oma in t he adrenal.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2885

19 - The Adrenal Glands

F igure 19- 32 Paraganglioma. A: Not e t he adrenals are normal in t his hy pert ensiv e w oman w it h end st age renal disease. B: A 1.8- c m het erogeneous bright ly enhanc ing ret roperit oneal mass (ar r ow ) is present . Paraganglioma w as c onf irmed by surgic al resec t ion.

F igure 19- 33 Organ of Zuc kerkandl paraganglioma. A: Coronal longit udinal relaxat ion t ime (T 1)- w eight ed image (500/20) show s t he adrenals (ar r ow s) are normal. B: A mass is present at t he aort ic bif urc at ion (ar r ow ).

Pheoc hromoc y t omas hav e a rat her c harac t erist ic appearanc e on MRI (44,53,135). Bec ause t hey are sev eral c ent imet ers in diamet er, t hey are readily det ec t ed, w it h a sensit iv it y of 100% in one report (149). When small, t hey usually are homogeneous and isoint ense t o musc le, hy point ense t o liv er on T 1- w eight ed images, and markedly hy perint ense t o f at on T 2- w eight ed images (44,165) (F igs. 19- 37 and 19- 38). As pheoc hromoc y t omas grow and dev elop c ent ral nec rosis, P.1335

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2886

19 - The Adrenal Glands

some c ent ral areas may be hy perint ense on bot h T 1- and T 2- w eight ed images (138) (see F ig. 19- 35). MR f indings may enable c harac t erizat ion of pheoc hromoc y t omas bec ause t he signal int ensit y of t hese t umors is somet imes v ery high on T 2- w eight ed images. Suc h a high signal int ensit y , w hic h is probably c aused by t he presenc e of a c y st ic c omponent , may be espec ially usef ul f or ext ra- adrenal t umors. If present , it c an also help dist inguish a pheoc hromoc y t oma f rom an adrenal adenoma (27,93).

F igure 19- 34 Pheoc hromoc y t oma. A: Unenhanc ed c omput ed t omography in t his pat ient w it h episodic hy pert ension show s homogeneous 4- c m right adrenal mass (ar r ow ); not e remaining normal port ion of right adrenal (open ar r ow ), and normal lef t adrenal (ar r ow heads). At t enuat ion w as 21 HU. B: Cort ic omedullary phase image af t er int rav enous c ont rast show st riking homogeneous enhanc ement of t he mass, 150 HU. C : On 15- minut e delay , t he at t enuat ion f ell t o 53 HU. A benign pheoc hromoc y t oma w as resec t ed af t er posit iv e bioc hemic al ev aluat ion.

Exuberant , persist ent enhanc ement af t er int rav enous gadolinium is t y pic al (95,165) (see F ig. 19- 38). Bec ause no lipid is f ound in pheoc hromoc y t oma, t here is no dec rease in signal on opposed phase images. Paragangliomas hav e similar dist inc t iv e imaging c harac t erist ic s; as a result , MRI is superior t o CT f or diagnosis of paragangliomas (131), and nearly as sensit iv e as MIBG (165). Bec ause most suc h t umors lie in t he adrenal or ret roperit oneum, sagit t al or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2887

19 - The Adrenal Glands c oronal MRI c an quic kly and ef f ec t iv ely show t he area of abnormalit y (138) (see F igs. 19- 35, 19- 37, 19- 38). Bec ause t he prev alenc e of pheoc hromoc y t oma/ paraganglioma is low , no imaging should be perf ormed unless t here is some c linic al or bioc hemic al ev idenc e of it s exist enc e. Eit her CT or MRI c an ef f ec t iv ely det ec t or exc lude an adrenal pheoc hromoc y t oma. If adrenal CT or MRI is negat iv e, no f urt her imaging should be perf ormed w it hout st rong bioc hemic al f indings. If t here is st rong c linic al or bioc hemic al ev idenc e, imaging of t he ent ire ret roperit oneum as w ell as t he adrenals should be perf ormed; eit her CT or MRI c an be used,

alt hough MRI may be pref erred bec ause of great er spec if ic it y and less c onc ern about c ont rast ef f ec t s. Biopsy of a mass suspec t ed t o be a pheoc hromoc y t oma is not rec ommended, espec ially if adequat e hy pert ensiv e c ont rol has not been ac hiev ed, bec ause sev eral episodes of sev ere hemorrhage and ev en deat h hav e result ed f ollow ing perc ut aneous biopsy (21,102). MIBG has bot h high sensit iv it y and high spec if ic it y , and it c an det ec t a paraganglioma in any part of t he body (49). How ev er, it is an expensiv e t est t hat requires up t o 72 hours t o c omplet e and is not w idely av ailable. F urt hermore, it does not prov ide suf f ic ient anat omic det ail f or surgic al planning. It is most usef ul in ev aluat ing pat ient s w it h a st rong c linic al suspic ion and in w hom CT or MRI is normal or equiv oc al, or f or f ollow - up of malignant lesions. T he f ollow - up f or t hese pat ient s should be v ery judic ious, and inf ormat ion on c linic al present at ions and surgic al dat a should be inc luded and t aken int o ac c ount during analy sis of examinat ion result s, w het her f rom a CT or f rom an MR. T he presenc e of hy pert ension in t his group of pat ient s is not alw ay s indic at iv e of persist enc e or rec urrenc e of t he disease. Ot her c auses of hy pert ension should be ev aluat ed, suc h as renal c hanges result ing f rom c hronic disease. Surgic al mat erials suc h as Surgic ell (Et hic on, Inc ., P.1336 Somerv ille, NJ) are f requent ly applied and may present as a “ mass” oc c upy ing perhaps t he spac e prev iously t aken by t he gland. T his c an lead t o misint erpret at ions of exam result s (F ig. 19- 39).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2888

19 - The Adrenal Glands

F igure 19- 35 Pheoc hromoc y t oma. A: Cont rast c omput ed t omography show s a 10- c m right suprarenal mass w it h marked het erogeneit y . B: Sagit t al longit udinal relaxat ion t ime (T 1)- w eight ed image (366/20) show t he mass is c learly separat e f rom t he kidney , as t he renal c ort ex is int ac t . Not e t he areas w it h signal as int ense as f at t hat c orrespond t o t he low - at t enuat ion areas on c omput ed t omography , probably represent ing hemorrhage. C : T ransv erse relaxat ion t ime (T 2)- w eight ed magnet ic resonanc e imaging (1800/80) show s most of t he mass is more int ense t han liv er, similar t o f at , but t he hemorrhagic areas are more int ense t han f at .

NONHYPERFUNCTIONING NEOPLASMS Nonhy perf unc t ioning adrenal neoplasms are c linic ally silent unt il t hey bec ome v ery large, alt hough t hey may present w it h pain if t hey hemorrhage. Current ly , most suc h masses are f ound inc ident ally on st udies perf ormed f or ot her reasons. About 30% of all adrenal masses are inc ident ally det ec t ed by CT (1). An adrenal mass is seen in about 4% of all abdominal CT sc ans, w it h one t hird being serendipit ous f indings; t he remainder are eit her met ast ases in pat ient s w it h know n malignanc ies, or t hey are f unc t ioning lesions (1). Most inc ident al

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2889

19 - The Adrenal Glands adrenal masses are benign and of no c linic al signif ic anc e, espec ially in pat ient s w it h no know n malignanc y . In t w o large series, only 6.7% and 9% of serendipit ous adrenal masses w ere subsequent ly prov ed malignant (3,50).

Alt hough hist oric ally size has been c onsidered an import ant f ac t or, w it h larger t umors hav ing a great er likelihood of malignanc y , size is an imperf ec t c rit erion. Alt hough malignant neoplasms w ere all larger t han 6.5 c m in one st udy (3) and alt hough most benign masses are less t han 5 c m (1,24), t here is c onsiderable ov erlap. Most inc ident al masses great er t han 5 c m are st ill benign in pat ient s w it h no hist ory of malignanc y (82), and lesions as small as 1 c m may be met ast ases (85). T hus, it is imperat iv e t o use imaging f eat ures ot her t han size t o make a diagnosis.

NONHYPERFUNCTIONING ADENOMAS Adrenal adenomas t hat do not produc e c linic ally signif ic ant exc ess hormones are not inf requent , being f ound in some 2% t o 8% of aut opsies (1,65) and in 1% t o 2% of abdominal CT sc ans (1,7,55). T hey are c ommonly P.1337 unilat eral, alt hough, seldom, bilat eral adenomas do oc c ur (F ig. 19- 40). Alt hough nonhy perf unc t ioning adenomas may be 6 c m or larger (85), most are 3 c m or less, and only 5% exc eed 5 c m (3). T he inc idenc e is slight ly higher in diabet ic (16%) and hy pert ensiv e pat ient s (12%) (85). Bec ause of t he f ac t t hat t hey do f unc t ion, t hey are “ w arm nodules” on adrenal sc int igrams. Calc if ic at ion may be present (80,107)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2890

19 - The Adrenal Glands

F igure 19- 36 Massiv e pheoc hromoc y t oma, nonf unc t ional. T his nonhy pert ensiv e pat ient present ed w it h abdominal pain; bioc hemic al ev aluat ion f or c at ec holamine exc ess w as negat iv e. A, B: Unenhanc ed c omput ed t omography images show s a 15 Г—16 c m right upper quadrant mass. C , D, E: Images af t er c ont rast show het erogenous enhanc ement w it h c ent ral nec rosis (ar r ow heads); origin is not c ert ain, but probably separat e f rom liv er and kidney . At surgery a large adrenal mass w as f ound, f inal pat hology pheoc hromoc y t oma.

Nonhy perf unc t ioning adenomas hav e a CT appearanc e indist inguishable f rom ot her adenomas, exc ept t hat c ont ralat eral at rophy is not present . T hey are

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2891

19 - The Adrenal Glands

smoot h, round or ov al, w it h a w ell- def ined margin. T hese adenomas are usually homogeneous w it hout a perc ept ible w all on nonc ont rast sc ans. CT densit omet ry c an be used t o ac c urat ely dif f erent iat e benign f rom malignant adrenal masses. Lee et al. (97) report ed t he use of nonenhanc ed CT at t enuat ion v alues f or t he c harac t erizat ion of adrenal masses w here most adenomas had at t enuat ion v alues low er t han t hose of malignant P.1338 P.1339 masses. Korobkin et al. (12) and Boland et al. (90) c onf irmed t hese f indings. Boland et al. pooled t he dat a f rom 10 art ic les and show ed t hat a sensit iv it y of 71% and a spec if ic it y of 98% result f rom c hoosing a t hreshold v alue of 10 HU f or t he diagnosis of adrenal adenoma (F igs. 19- 41, 19- 42) (12). Of homogeneous adrenal masses w it h a nonenhanc ed CT at t enuat ion v alue of 10 HU or less, 98% w ill be benign (most w ill be adenomas), w hereas 29% of adenomas w ill hav e an at t enuat ion v alue of more t han 10 HU and w ill be indist inguishable f rom most nonadenomas, inc luding met ast ases.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2892

19 - The Adrenal Glands

F igure 19- 37 Pheoc hromoc y t oma v ersus renal c arc inoma. T his 42- y ear- old man present ed w it h malignant hy pert ension in t he emergenc y depart ment . A: Unenhanc ed c omput ed t omography rev eals homogeneous 4.7- c m mass w it h at t enuat ion 33 HU (ar r ow ). B, C : Post c ont rast images show t he enhanc ing

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2893

19 - The Adrenal Glands mass (ar r ow ) int imat ely assoc iat ed w it h t he right kidney (ar r ow heads): it is unc lear w het her it is of renal or adrenal origin. D: On magnet ic resonanc e imaging, c omparison of in phase breat h- hold longit udinal relaxat ion t ime (T 1) and (E) opposed phase image show no drop in signal of t he mass. F : On t ransv erse relaxat ion t ime (T 2)- w eight ed image, t he mass (ar r ow ) is homogeneous and quit e hy perint ense. (G) Coronal breat h- hold T 1 image af t er int rav enous gadolinium diet hy lene- t riamine pent a- ac et ic ac id show marked het erogeneous enhanc ement and a c lear plane of separat ion f rom t he kidney (ar r ow heads). F ollow ing posit iv e bioc hemic al ev aluat ion, an adrenal pheoc hromoc y t oma w as resec t ed.

F igure 19- 38 Pheoc hromoc y t oma. A: longit udinal relaxat ion t ime (T 1) –w eight ed gradient ref oc used ec ho image during suspended respirat ion show s a 4- c m het erogeneous lef t adrenal mass (ar r ow ). B: On f at - suppressed t ransv erse relaxat ion t ime (T 2)–w eight ed image, t he mass (ar r ow ) is markedly hy perint ense. C : F ollow ing int rav enous gadolinium diet hy lenet riamine pent a- ac et ic ac id, t he mass show s marked het erogeneous enhanc ement , w hic h persist ed f or sev eral minut es.

Anot her approac h t o CT densit omet ry f or c harac t erizat ion of adrenal masses makes use of t he “ hist ogram” f unc t ion av ailable on most sc anners. T he aut hors plac ed a c irc ular region of int erest c ov ering t he c ent er t w o t hirds

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2894

19 - The Adrenal Glands

(av oiding t he periphery t o limit v olume av eraging) of adrenal masses inc luding 90 adenomas on unenhanc ed CT , 184 adenomas on enhanc ed CT , and 31 adrenal met ast ases on enhanc ed CT (4). T he hist ogram is a plot of pixel at t enuat ion along t he x axis w it h t he f requenc y of eac h at t enuat ion v alue along t he y axis, and also prov ides mean at t enuat ion, number of pixels, and range of pixel at t enuat ion. T he aut hors show ed t hat none of t he adrenal met ast ases c ont ained any negat iv e pixels on enhanc ed CT , w hereas 52% of t he adenomas did, 51% hav ing more t han 10% negat iv e pixels. On unenhanc ed CT , 87 of t he 90 adenomas had negat iv e pixels, inc luding 14 of t he 16 t hat had mean at t enuat ion abov e 10 HU (4). T hus use of t his met hod may allow a quic k opt ion t o diagnose adenoma ev en af t er c ont rast , alt hough pot ent ial pit f alls c ould result f rom v arianc e in sc an t ec hnique (may be susc ept ible t o art if ac t f rom high noise prof ile) and c alibrat ion. Chemic al shif t MRI c an be used t o dif f erent iat e adrenal nodules. A relat iv e loss in signal int ensit y in an adrenal mass, w hen opposed- phase and in- phase images are c ompared, c an also be used t o c harac t erize many adrenal masses as benign adenomas (F igs. 19- 42, 19- 43). Adrenal adenomas, unlike most met ast ases and ot her nonadenomas, of t en c ont ain large amount s of int rac ellular lipid (106). T he sensit iv it y and spec if ic it y f or t he diagnosis of adrenal adenoma are similar f or c hemic al shif t MR imaging and nonenhanc ed CT densit omet ry (121). A hist ologic st udy of resec t ed adenomas t hat had undergone presurgic al CT or MR imaging show ed a linear c orrelat ion bet w een t he perc ent age of lipid- ric h c ort ic al c ells and bot h t he nonenhanc ed CT at t enuat ion v alue and t he relat iv e c hange in signal int ensit y on opposedphase c hemic al shif t MR images (91).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2895

19 - The Adrenal Glands

F igure 19- 39 Pheoc hromoc y t oma; post operat iv e f inding. A: Enhanc ed c omput ed t omography in t his hy pert ensiv e pat ient demonst rat es a v igorously enhanc ing right adrenal mass. B: T he mass (ar r ow ) is markedly hy perint ense on f at - suppressed t ransv erse relaxat ion t ime (T 2)- w eight ed image. Pheoc hromoc y t oma w as c onf irmed by surgic al resec t ion. Post - adrenalec t omy (C ) longit udinal relaxat ion t ime (T 1) and (D) T 2- w eight ed magnet ic resonanc e images show a small mass- like lesion in adrenalec t omy bed (c ur v ed ar r ow ). At surgery , t he adrenal bed w as pac ked w it h Surgic el f or hemost asis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2896

19 - The Adrenal Glands

F igure 19- 40 Biopsy - prov ed bilat eral nonhy perf unc t ioning adenomas in a pat ient w it h bronc hogenic c arc inoma. Post c ont rast c omput ed t omography image demonst rat es bilat eral adrenal masses (ar r ow s), eac h measuring 1.5 c m in diamet er. Bot h masses hav e homogeneous near- w at er at t enuat ion v alues. T his c omput ed t omography appearanc e is c harac t erist ic of a nonhy perf unc t ioning adenoma.

F igure 19- 41 Adenoma. An 18- mm low - at t enuat ion (- 18 HU) right adrenal adenoma (ar r ow ) w as disc ov ered inc ident ally in t his asy mpt omat ic man. T he c omput ed t omography f inding of a mass w it h at t enuat ion t his low exc ludes malignanc y .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2897

19 - The Adrenal Glands

F igure 19- 42 Nonhy perf unc t ioning adenoma. A: T his pat ient present ed w it h a lef t low er pole renal c arc inoma (ar r ow ), hav ing had prior right nephrec t omy f or renal c arc inoma 20 y ears prev iously . B: A lef t adrenal nodule (ar r ow ) w as f ound on t he st aging c omput ed t omography . C : At t enuat ion on unenhanc ed c omput ed t omography w as 7 HU. On magnet ic resonanc e imaging, t here is drop in signal c omparing (D) in phase and (E) opposed phase gradient ref oc used ec ho longit udinal relaxat ion t ime (T 1) images. Radic al nephrec t omy w as perf ormed c onf irming benign nonhy perf unc t ioning adenoma.

P.1340 P.1341 A subst ant ial minorit y of adrenal adenomas is lipid- poor and c annot be c harac t erized by means of t heir nonenhanc ed CT at t enuat ion (F igs. 19- 44, 19- 45). Korobkin (87), est ablished w ashout c urv e v alues f or adenomas. T he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2898

19 - The Adrenal Glands adenomas, not w it hst anding t he presenc e and quant it ies of lipids in t heir c omposit ion, hav e t he propert y of present ing rapid loss of enhanc ement and at t enuat ion v alues at 15 minut es, w hic h c an be used t o dif f erent iat e adenomas f rom ot her masses (F ig. 19- 45). T he est ablished f ormula f or t his c alc ulat ion inc ludes t he densit y of t he lesion during t he prec ont rast , port al (60- sec ond) and 15- minut e delay phases. T he

examinat ion should be perf ormed w it h an appropriat e t ec hnique w it h t hin slic es and densit y measurement s w it h region of int erest spanning one half t o t w o t hirds of t he area of t he lesion, alw ay s in t he same posit ion. Calc if ic at ion and nec rosis areas should be av oided w hen t aking t he measurement s. Adrenal masses t hat c ont ain subst ant ial port ions of inhomogeneously low at t enuat ion, w hic h indic at e subst ant ial c omponent s of nec rosis or c y st ic c hange, c annot be c harac t erized by means of delay ed enhanc ement w ashout c alc ulat ions. T he abnormal or absent c apillary beds in t hese exc av at ed regions w ill probably show slow enhanc ement w ashout regardless of t he original underly ing hist ologic c ause (15). In t he equat ion % enhanc ement w ashout =(E- D/E- U) 100, w here E = enhanc ement : at t enuat ion at port al P.1342 phase, D = delay ed enhanc ed at t enuat ion at 15 minut es, and U = at t enuat ion at prec ont rast , t he perc ent age enhanc ement w ashout represent s t he perc ent age of t he init ial w ash in of enhanc ement t hat is w ashed out at t he t ime of delay ed sc anning, as f ollow s: perc ent age enhanc ement w ashout equals (enhanc ement w ashout div ided by enhanc ement ) mult iplied by 100.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2899

19 - The Adrenal Glands

F igure 19- 43 Inc ident al benign adenoma, disc ov ered during magnet ic resonanc e angiography f or renal art ery st enosis. A: In- phase longit udinal relaxat ion t ime (T 1) gradient ref oc used ec ho (GRE) magnet ic resonanc e imaging images show s small right adrenal nodule (ar r ow ) near isoint ense w it h spleen. B: Opposed- phase GRE T 1 image show s lesion is c learly muc h less int ense t han spleen, t his signal drop indic at ing presenc e of int rac ellular lipid. C : On f at - suppressed t ransv erse relaxat ion t ime (T 2)- w eight ed image, t he lesion is only slight ly more int ense t han liv er. D: T 1 GRE image af t er int rav enous gadolinium diet hy lene- t riamine pent a- ac et ic ac id show s mild enhanc ement .

T he relat iv e enhanc ement w ashout c an also be used and is an approximat ion of t he t rue enhanc ement w ashout ; it relat es t he enhanc ement w ashout t o t he enhanc ed at t enuat ion v alue inst ead of t he enhanc ement w ash in, as f ollow s: relat iv e perc ent age enhanc ement w ashout equals (enhanc ement w ashout div ided by enhanc ed at t enuat ion) mult iplied by 100 (87). T he relat iv e enhanc ement w ashout of an adrenal mass w as a c onc ept int roduc ed as an approximat ion t o t he t rue enhanc ement w ashout t hat c ould be used w hen a delay ed enhanc ed sc an is obt ained af t er an adrenal mass is depic t ed on a st andard enhanc ed CT sc an, w it hout know ledge of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2900

19 - The Adrenal Glands

nonenhanc ed at t enuat ion. It is not a phy siologic c onst ruc t , how ev er, bec ause it relat es t he amount of at t enuat ion loss t o only t he enhanc ed at t enuat ion v alue and not t o t he gain in at t enuat ion v alue af t er t he administ rat ion of a c ont rast mat erial (88). Relat iv e w ashout = E/D Г— 100 Most adrenal c ort ic al c arc inomas are larger t han 6 c m at present at ion and of t en hav e demonst rable met ast ases. T y pic ally , t hese t umors also hav e large amount s of nec rosis, w hic h w ould inv alidat e at t empt s t o assess enhanc ement w ashout . Despit e t his more c ommon present at ion of adrenal c ort ic al c arc inoma, t he possibilit y of dif f erent iat ing t he P.1343 rare small adrenal c ort ic al c arc inoma f rom t he more c ommon adrenal adenoma bet w een 3 and 6 c m in diamet er by using enhanc ement w ashout c alc ulat ions has not y et been sy st emat ic ally assessed (88).

F igure 19- 44 At y pic al adrenal adenoma. A: St aging c omput ed t omography in t his pat ient present ing w it h lung c anc er rev ealed bilat eral adrenal masses (ar r ow s), 2 c m on t he right and 3.5 c m on lef t . Bot h measured - 5 HU on unenhanc ed c omput ed t omography . B: Not e on t his enhanc ed t he lef t adrenal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2901

19 - The Adrenal Glands

lesion is somew hat het erogeneous. C : Bec ause of t he size and het erogeneit y , biopsy of t he lef t adrenal mass w as perf ormed, rev ealing benign adenoma.

T he ev aluat ion of a know n adrenal mass st art s by using nonenhanc ed CT . If t he at t enuat ion of t he mass is 10 HU or less t he diagnosis is, in most c ases, a lipid- ric h adrenal adenoma, and a small f rac t ion of t hese w ill be c y st s. In suc h a c ase, t here is no need f or f urt her ev aluat ion. If t he at t enuat ion is more t han 10 HU, t he mass is c onsidered t o be indet erminat e and an enhanc ed and 15- minut e- delay ed enhanc ed CT sc an should be perf ormed. If t he enhanc ement w ashout is more t han 60%, t he most likely diagnosis is of a lipidpoor adenoma. Again, t here is no need f or f urt her ev aluat ion. If t he enhanc ement w ashout is less t han 50%, t he mass is c onsidered indet erminat e. Perc ut aneous adrenal biopsy is rec ommended if t he pat ient has a primary neoplasm w it hout ot her ev idenc es of met ast ases. In a pat ient w it hout c anc er, surgery is rec ommended if t he mass measures more t han 4 t o 5 c m. F ollow - up CT , or adrenal sc int igraphy w it h t he use of radio- iodinat ed norc holest erol, c an also be perf ormed in t his group of pat ient s. Nonhy perf unc t ioning adenomas also hav e c harac t erist ic MRI f eat ures. On MRI, t he mass is homogeneous w it h signal int ensit y usually less t han t hat of f at but great er t han t hat of musc le on all sequenc es (23). In most c ases, t he signal int ensit y is similar t o t hat of normal liv er on bot h T 1- and T 2- w eight ed images (23,26,44,53,135) (F ig. 19- 46). How ev er, signal int ensit ies are af f ec t ed by many f ac t ors and c an be v ariable, suc h t hat diagnosis based only on signal int ensit ies may be indet erminat e in as muc h as 21% t o 31% (5,26,134). Af t er int rav enous administ rat ion of gadolinium c ompounds, adenomas show limit ed enhanc ement (4 c m maximal diamet er) in one t hird of c ases. T here is a st rong assoc iat ion w it h endomet rial hy perplasia and t hese pat ient s are at inc reased risk f or dev elopment of endomet rial c arc inoma.

Computed Tomography and Magnetic Resonance Imaging of Benign Adnexal Masses Computed Tomography T he dif f erent ial diagnosis f or benign c y st ic lesions of t he ov ary inc ludes simple c y st s of v arious origins, dermoids, endomet riomas, c y st adenomas, and t uboov arian absc ess. On CT sc an, t he ov ary should measure no more t han 4 c m in maximum diamet er. It is usually of sof t t issue densit y ; how ev er, small f ollic les may be seen, part ic ularly f ollow ing P.1384 t he administ rat ion of int rav enous c ont rast agent s. Simple c y st s may represent a dominant f ollic le or c orpus lut eum c y st (F ig. 20- 11). T hey are of f luid densit y and hav e no int ernal arc hit ec t ure. In w omen of c hildbearing age, any c y st less t han 4 c m in diamet er does not merit f ollow - up, w it h t he exc ept ions of t hose pat ient s w it h know n malignanc ies in w hic h met ast ases are a c onsiderat ion (88). In post menopausal w omen, all c y st s great er t han 1 c m should probably be f ollow ed w it h US bec ause of t he higher likelihood of malignanc y .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2976

20 - Pelvis

F igure 20- 8 Ut erine f ibroids. A: Axial T 2- w eight ed t urbo spin- ec ho (T SE) (4902/132) magnet ic resonanc e (MR) image show s an enlarged, ov oid shaped ut erus. T he high signal endomet rial c anal is dist ort ed and dev iat ed t o t he right by a c onglomerat e mass of predominant ly low signal, c ollagenous f ibroids (ar r ow ). B: Sagit t al T 2- w eight ed T SE (4902/132) MR image of t he same pat ient demonst rat es t hat t he normal int ermediat e signal my omet rium has been nearly ent irely replac ed by low - signal f ibroids. T here are bilat eral hy drosalpinges (ar r ow s). C : Sagit t al T 2- w eight ed SE image (2100/90) show s low - signal- int ensit y mass (m) c ompressing endomet rial st ripe (ar r ow s) inf eriorly .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2977

20 - Pelvis

F igure 20- 9 Adenomy osis. A: Sagit t al T 2- w eight ed f ast spin- ec ho (F SE) (4500/108) magnet ic resonanc e image show s enlargement of t he ut erus and a markedly t hic kened low signal junc t ional zone (ar r ow heads). Mult iple f oc i of high T 2 signal are present . B: Axial image using t he same t ec hnique show s t he high T 2 f oc i t o be endomet rial glands ext ending int o t he adenomy oma (ar r ow ). Bilat eral high T 2 signal ov arian c y st s are present .

P.1385

Dermoid Mat ure t erat oma or dermoid is an ov arian mass c omposed of t issue arising f rom t he endo- , meso- , and ec t oderm. It is a benign lesion t hat is bilat eral in approximat ely 25% of c ases. Ident if ic at ion is usually st raight f orw ard. An ec hogenic mass w it h dense post erior shadow ing (t he t ip of t he ic eberg sign) is seen on US. On CT , a f at densit y mass w it h or w it hout a f at –f luid lev el is present (F ig. 20- 12). T he high- densit y Rokit ansky nodule, c omposed of hair and ot her c omponent s, may f loat w it hin t he c ent er of t he mass and c alc if ic at ion is of t en present . Dermoids w it hout mac rosc opic f at hav e been report ed, are rare, and c annot be c onf ident ly diagnosed using any modalit y . Most asy mpt omat ic dermoids smaller t han 4 c m are lef t in plac e. T hose larger P.1386 t han 4 c m are of t en remov ed bec ause of t he higher risk of ov arian t orsion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2978

20 - Pelvis

F igure 20- 10 Poly c y st ic ov aries. Axial (A) and c oronal (B) T 2- w eight ed f ast spin- ec ho (F SE) (4500/108) magnet ic resonanc e image show s enlarged ov aries bilat erally w it h an inc reased v olume of c ent ral st roma (ar r ow s) displac ing t he f ollic les peripherally .

F igure 20- 11 Benign ov arian c y st . Cont rast - enhanc ed c omput ed t omography sc an of t he pelv is show s a w ell- c irc umsc ribed, nonenhanc ing st ruc t ure of w at er densit y (c ) arising f rom t he lef t ov ary c onsist ent w it h benign c y st . Not e right ov ary (ar r ow ) and ut erus (u).

Endometriosis Laparosc opy remains t he t est of c hoic e f or diagnosing and st aging endomet riosis bec ause t he majorit y of disease c onsist s of small solid implant s in t he ut erine c ul- de- sac , along t he f allopian t ubes, and adjac ent t o t he ov aries. CT , t ransv aginal US, and MRI are of use only w hen t he diagnosis of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2979

20 - Pelvis an endomet rioma is suspec t ed. On c ont rast - enhanc ed CT images,

endomet riomas may be uni- or mult iloc ular and are of t en higher in densit y t han c lear f luid (F ig. 20- 13). Int ermediat e densit y debris is of t en seen w it hin t he dependent port ion of t he endomet rioma. No inf lammat ory st randing of f at surrounds t his adnexal mass. T he main dif f erent ial diagnosis is t hat of a hemorrhagic c y st and endov aginal US is of t en of use in dist inguishing bet w een t he t w o ent it ies.

F igure 20- 12 Ov arian dermoid. A: Axial c ont rast - enhanc ed c omput ed t omography images show a large mass w it hin t he right side of t he pelv is t hat c ont ains f at (ar r ow ), sof t t issue and c alc if ic densit ies. In B, t he mass is seen t o arise f rom t he right ov arian pedic le (ar r ow ).

Cystadenoma Ov arian c y st adenomas of t en are quit e large w hen t hey f irst present . T hey appear as w ell- def ined, uni- or mult iloc ular, low - densit y masses. T he w alls and int ernal sept a are of v ary ing t hic kness and regularit y (F ig. 20- 14). Papillary projec t ions of sof t t issue densit y may be seen w it hin t he t umor. Whereas serous c y st adenoma has a CT densit y approac hing t hat of w at er, muc inous c y st adenoma has a densit y slight ly less t han t hat of sof t t issue. Amorphous, c oarse c alc if ic at ions somet imes c an be seen in t he w all or w it hin t he sof t t issue c omponent of a serous c y st adenoma. Alt hough t he presenc e of a t hic k, irregular w all, irregular sept a, and enhanc ing sof t t issue projec t ions or nodules suggest s malignanc y , malignant ov arian c y st adenoc arc inomas c annot be reliably dist inguished f rom benign c y st adenomas unless met ast ases are present (99,62). In one st udy , 69% of benign serous c y st adenomas and 62% of benign

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2980

20 - Pelvis muc inous c y st adenomas w ere c orrec t ly c harac t erized based on CT f indings (99).

Tuboovarian Abscess Usually a sequela of pelv ic inf lammat ory disease or gy nec ologic inst rument at ion, f ormat ion of t uboov arian c omplex is sec ondary t o inf ec t ion w it h gonorrhea or c hlamy dia. T he f allopian t ube bec omes dilat ed and obst ruc t ed, usually P.1387 by a c ombinat ion of blood and pus. T he ov ary is of t en inv olv ed in t he result ant inf lammat ory mass, somet imes c alled a t uboov arian c omplex. T he proc ess may be uni- or bilat eral. On c ont rast - enhanc ed CT imaging, t uboov arian c omplex has t he appearanc e of an enhanc ing mass w it h c y st ic and solid c omponent s (F ig. 20- 15). T here is ext ensiv e st randing of adjac ent f at . Dif f erent ial diagnosis inc ludes t orsion, div ert ic ulit is, appendic it is, and ov arian neoplasm; how ev er, t he presenc e of f ev er, c erv ic al mot ion t enderness, and appropriat e hist ory w ill usually point t o t he c orrec t diagnosis. Primary t reat ment is ant ibiot ic t herapy f or 48 t o 72 hours. If t his regimen f ails, perc ut aneous or surgic al drainage is usually perf ormed.

F igure 20- 13 Endomet rioma. A and B: Axial c ont rast - enhanc ed c omput ed t omography images show a large c y st ic lesion ant erior and superior t o t he ut erus (ar r ow s) w it h densit y slight ly higher t han urine and c ont aining at least one sept at ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2981

20 - Pelvis

F igure 20- 14 Cy st adenoma. A and B: Axial c ont rast - enhanc ed c omput ed t omography images show a large f luid densit y c y st ic mass w it h mult iple predominant ly t hin sept at ions (ar r ow s) and no assoc iat ed asc it es.

Ovarian Torsion Rot at ion of t he ov ary on it s long axis w it h result ant v asc ular and ly mphat ic obst ruc t ion c onst it ut es ov arian t orsion. It most c ommonly oc c urs in c hildren and adolesc ent s. P.1388 T he c ause is usually an ov arian mass suc h as a c y st or dermoid. Bec ause t he ov ary has t w o art erial blood supplies, one arising f rom t he ut erus, and t he sec ond, t he gonadal art ery , assoc iat ed hemorrhage is c ommon. T he appearanc e on CT sc ans is t hat of a hemorrhagic solid or, in lat e c ases, c y st ic mass (78). T he engorged ov ary is usually large enough t o displac e adjac ent organs (F ig. 20- 16). T here is of t en an assoc iat ed dilat ed or hemorrhagic f allopian t ube. T reat ment is emergent salpingo- oophorec t omy . T radit ionally , an adnexal mass larger t han 4 c m in a y oung f emale has been remov ed prophy lac t ic ally bec ause of t he presumed higher inc idenc e of t orsion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2982

20 - Pelvis

F igure 20- 15 T uboov arian absc ess. Axial c ont rast - enhanc ed c omput ed t omography images at t w o lev els, A and B, in t he pelv is show a bilobed c y st ic and solid mass arising f rom t he right adnexa (ar r ow , A). T here is ext ensiv e st randing in t he adjac ent f at (ar r ow , B) and f luid and debris w it hin t he endomet rial c anal.

F igure 20- 16 Ov arian t orsion. Axial c ont rast - enhanc ed c omput ed t omography images at t w o lev els, A and B, in t he pelv is show a large c y st ic st ruc t ure (ar r ow , A) displac ing t he ut erus post eriorly (ar r ow , B). T he pat ient had been c at het erized t o dec ompress t he bladder. F ree f luid is seen w it hin t he c ul- desac .

Magnetic Resonance Imaging Similar t o CT , t he normal ov arian st roma is of int ermediat e signal int ensit y . High T 2- signal f ollic les are dispersed P.1389

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2983

20 - Pelvis t hroughout . T he dif f erent ial diagnosis f or a simple c y st remains t he same; how ev er, int ernal arc hit ec t ure c annot be adequat ely disc erned on T 2w eight ed images alone and rev iew of t he c ont rast - enhanc ed images is nec essary t o asc ert ain t he absenc e of sept a and nodules (69).

F igure 20- 17 Ov arian dermoid. A: Axial T 1- w eight ed spin ec ho (800/11) magnet ic resonanc e (MR) image show s a c omplex pelv ic mass c ont aining signal similar t o t hat of t he abdominal w all f at as w ell as mult iple f luid lev els (ar r ow s). B: Axial T 2- w eight ed f ast spin- ec ho (F SE) (600/102) MR image demonst rat es bot h t he c hemic al shif t (ar r ow ) and int ernal spec kling art if ac t s diagnost ic of dermoid.

Dermoid On T 1- and T 2- w eight ed images, t he f at w it hin t he dermoid w ill f ollow t he signal c hanges of f at w it hin t he subc ut aneous t issues. F at c an be def init ely ident if ied and separat ed f rom high T 1 signal blood using f at suppression pulse sequenc es (95). T he c hemic al shif t art if ac t c onsist ing of an adjac ent blac k and w hit e line at t he edge of t he t erat oma in t he f requenc y enc oding direc t ion (usually right t o lef t on axial images) is also diagnost ic of mac rosc opic f at (F ig. 20- 17). On T 2- w eight ed images, t he spec kling art if ac t w it hin t he Rokit ansky nodule is v irt ually diagnost ic of a dermoid. It is c omposed of my riad c hemic al shif t art if ac t s inv olv ing hair and adjac ent f at . In some c ases, a dermoid mimic s adjac ent bow el and t he sigmoid c olon must be c aref ully rev iew ed t o separat e it f rom t he adnexa.

Endometriosis

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2984

20 - Pelvis

Endomet riomas may be uni- or mult iloc ular and are of predominant ly high signal on T 1- and T 2- w eight ed images. On T 2- w eight ed images, int ermediat e signal shading, result ing f rom T 2 short ening of blood produc t s, is of t en seen w it hin t he mass. Rec urrent bleeding may lead t o a v ery low signal hemosiderin rim (F ig. 20- 18). Adjac ent bow el loops may be t et hered t o t he mass. Conf ident diagnosis c an be dif f ic ult w hen some of t he abov e MRI f eat ures are absent . Dif f erent iat ion f rom a dermoid c an be part ic ularly dif f ic ult w hen t he lat t er c ont ains a large amount of high- T 2- signal debris (70,91).

Cystadenoma Ov arian c y st adenomas of t en appear as large pelv ic masses (34,62). T he signal c harac t erist ic s of t hese masses dif f er depending on t he c hemic al c omposit ion of t he c y st f luid and t he amount of solid c omponent s c ont ained w it hin t he t umor (F ig. 20- 19). Alt hough t he ac c urac y f or dist inguishing bet w een benign and malignant ov arian lesions improv es w it h t he addit ion of Gd- enhanc ed MR images (34,62,104), malignant ov arian c y st adenoc arc inomas c annot be reliably dif f erent iat ed f rom benign c y st adenomas unless met ast ases are present .

Tuboovarian Abscess Alt hough it is ext remely unusual f or diagnosis of t uboov arian absc ess t o require MRI, f indings inc lude f ree pelv ic f luid, a dilat ed f allopian t ube, and c omplex c y st ic mass (96). It is possible t hat a large absc ess may mimic an ov arian neoplasm. Bot h masses c onsist of c y st ic and solid c omponent s and hav e t hic k c apsules and sept a (71). Asc it es may also be present in bot h c linic al sc enarios. In t his c ase, c linic al hist ory should be t aken int o c onsiderat ion and a c aref ul searc h made f or inf lammat ory st randing of t he pelv ic f at . St randing almost alw ay s heralds t he presenc e of an inf lammat ory rat her t han a neoplast ic proc ess.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2985

20 - Pelvis

F igure 20- 18 Bilat eral endomet riomas. A: Axial T 2- w eight ed f ast spin- ec ho (F SE) (5266/90) magnet ic resonanc e (MR) image show s bilat eral adnexal masses of low t o int ermediat e signal (ar r ow s). A low - signal hemosiderin ring surrounds t he right mass. B: Axial T 1- w eight ed (566/14) MR image demonst rat es t hat t he lef t mass is now of high signal (ar r ow ) w hereas t he right is of low signal (ar r ow ), indic at ing t he presenc e of blood produc t s. C : Axial c ont rast - enhanc ed (410/4.2) MR image w it h f at sat urat ion show s no w all nodularit y t o suggest malignanc y .

P.1390

Gynecologic Neoplasms Most gy nec ologic onc ologist s st age pelv ic neoplasms ac c ording t o t he Int ernat ional F ederat ion of Gy nec ology and Obst et ric s (F IGO) sy st em. T his

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2986

20 - Pelvis

f orm of c linic al st aging relies on a high- qualit y phy sic al examinat ion perf ormed under general anest hesia. Numerous radiologic t est s are t hen perf ormed, inc luding c hest radiograph, barium enema, and int rav enous py elogram. Hardest y et al. (37) demonst rat ed t hat , w hen st aging endomet rial c anc er, perf orming a single MR examinat ion of t he pelv is c an replac e all of t he anc illary examinat ions (w it h t he exc ept ion of t he c hest radiograph) at a similar c ost (37). T he preoperat iv e use of MRI w as also f ound t o dec rease t he number of unnec essary ly mph node dissec t ions. Gy nec ologic onc ologist s argue t hat onc e a signif ic ant gy nec ologic mass is det ec t ed imaging is unnec essary bec ause t he presumed t umor must be remov ed using an ext ensiv e onc ologic t y pe resec t ion t hat is bot h diagnost ic and t herapeut ic . T here is agreement t hat CT or MRI is of part ic ular v alue in t he c ase of adv anc ed disease in w hic h t he primary t herapy should be c hemot herapy and not surgery and should prec ede or replac e t he sec ond- look operat ion in ident if ic at ion of rec urrent met ast ases. St aging c rit eria f or t he gy nec ologic malignanc ies using bot h t he T NM and F IGO sy st ems are delineat ed in T ables 20- 1, 20- 2, 20- 3. Opt imal CT t ec hnique requires exc ellent bow el opac if ic at ion. Int roduc t ion of rec t al c ont rast medium, alt hough not essent ial, c an be of help in dif f ic ult c ases suc h as t hose w it h mult iple masses or inv asion of t he c olon. Int rav enous c ont rast should be administ ered at a rapid rat e and sc ans 5 mm in t hic kness obt ained f ollow ing a delay of 70 t o 80 sec onds. T his delay allow s good c harac t erizat ion of t he P.1391 pelv ic mass and opac if ic at ion of bot h pelv ic art eries and v eins, f ac ilit at ing ident if ic at ion of abnormal ly mph nodes. MRI should c onsist of sagit t al and axial T 2- w eight ed images, opt imally obt ained w it h a mult ic oil array and f ast - pulse sequenc es and dy namic images immediat ely post int rav enous administ rat ion of Gd- DT PA. T hese c ont rast - enhanc ed images bet t er c harac t erize c erv ic al and ov arian masses and c an separat e t hem f rom adjac ent st ruc t ures suc h as t he bladder and rec t um.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2987

20 - Pelvis

F igure 20- 19 Cy st adenoma. Axial T 2- w eight ed t urbo spin- ec ho (T SE) (4902/82) magnet ic resonanc e image of t he pelv is show s a high- signal mult iloc ular c y st ic mass w it hout w all nodularit y (ar r ow s). T his appearanc e suggest s benignit y .

Using eit her CT or MRI, it is best t o approac h gy nec ologic malignanc ies in a sy st emat ic w ay . T he sourc e of t he pelv ic mass should be ident if ied w henev er possible. Bec ause gy nec ologic malignanc ies spread v ia direc t ext ension and t he ly mphat ic s, all images should be sc rut inized f or t he presenc e of asc it es, perit oneal met ast ases, and enlarged ly mph nodes. Asc it es ext ends along t he pat h of least resist anc e post eriorly int o t he c ul- de- sac , along t he right parac olic gut t er, and ov er t he t op of t he liv er. Perit oneal implant s also f ollow t his rout e f irst and t hen ext end t o t he lef t parac olic gut t er and medial t o t he spleen. Direc t ext ension may oc c ur ant eriorly t o t he great er oment um. Ly mphat ic spread oc c urs lat erally t o t he pelv ic sidew alls, post eriorly t o t he presac ral spac e and superiorly t o t he lev el of t he renal art eries. Ly mph nodes great er t han 1 c m in diamet er indic at e met ast at ic disease in approximat ely 65% of c ases (106). F inally , hy dronephrosis is a c ommon c omplic at ion of gy nec ologic malignanc y and surgic al t herapy . It is import ant t hat it be ident if ied early t o salv age t he kidney bef ore t he onset of c hemot herapy . Visc eral and c hest met ast ases oc c ur only in ext remely adv anc ed disease. TABLE 20- 1 STAGING OF C ERVIC AL C ARC INOMA

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2988

20 - Pelvis TNM C a te gorie s

F IGO Surgic a l Sta ge s

TX T0 T is T1

0 I

IA

T 1a1

IA1

T 1a2

IA2

T 1b T2

IB II

T 2a

IIA

T 2b T3

IIB III

T 3a

IIIA

T 3b

IIIB

T4

IVA

Computed Body Tomography with MRI Correlation , 4th Edition

C rite ria Primary t umor c annot be assessed. No ev idenc e of primary t umor. Carc inoma in sit u Cerv ic al c arc inoma c onf ined t o ut erus (ext ension t o c orpus should be disregarded). Prec linic al inv asiv e c arc inoma, diagnosed by mic rosc opy only . Minimal mic rosc opic st romal inv asion 3 mm or less in dept h, t aken f rom t he base of t he epit helium and 7 mm or less in horizont al spread. T umor w it h inv asiv e c omponent 5 mm or less in dept h, t aken f rom t he base of t he epit helium, and 7 mm or less in horizont al spread. T umor larger t han T 1a2. Cerv ic al c arc inoma inv ades bey ond ut erus but not t o pelv ic w all or t o low er t hird of t he v agina. Wit hout paramet rial inv asion. Wit h paramet rial inv asion. Cerv ic al c arc inoma ext ends t o pelv ic w all and/or inv olv es t he low er t hird of t he v agina and/or c auses hy dronephrosis or nonf unc t ioning kidney . T umor inv olv es low er t hird of t he v agina; no ext ension t o pelv ic w all. T umor ext ends t o t he pelv ic w all and/or c auses hy dronephrosis or nonf unc t ioning kidney . T umor ext ends out side t rue pelv is or has inv olv ed muc osa of t he bladder or rec t um.

© 2017 Enter your company name

2989

20 - Pelvis Used w it h t he permission of t he Americ an Joint Commit t ee on Canc er (AJCC), Chic ago. T he original sourc e f or t his mat erial is Greene F L, F leming ID, Page DL, et al., eds. AJCC c anc er st aging m anual, 6t h ed. New Y ork: SpringerVerlag, 2002, ht t p://w w w .springer- ny .c om

Computed Tomography Cervical Cancer Cerv ic al c anc er is a usually a disease of w omen of menst rual age t hat plat eaus at age 40 y ears in Americ an w omen. Approximat ely 13,000 new c ases are diagnosed eac h y ear (48). Causalit y by human papilloma v irus has been generally ac c ept ed and t he v ast majorit y of t umors are of squamous c ell origin (79). Pat ient s are usually asy mpt omat ic and det ec t ion is usually v ia t he Papanic olaou smear. T he majorit y of c anc ers are c onf ined t o t he c erv ic al c anal w hen disc ov ered. T hey are t reat ed w it h a v ariet y of loc al t herapies inc luding P.1392 laser ablat ion. Any c erv ic al mass t hat is great er t han 1.5 c m or presumed t o ext end bey ond t he c erv ix should be examined using MRI. CT sc anning lac ks t he c ont rast resolut ion nec essary f or primary st aging of relat iv ely low v olume disease, w it h ov erall st aging ac c urac y report edly ranging f rom 60% t o 80% (16,53). In c ases of adv anc ed disease, CT is pref erred (F ig. 20- 20). It is quic k t o perf orm and read and has a higher spat ial resolut ion t han MRI. T he c erv ix is of t en enlarged in t he ant erior- post erior direc t ion and may c ont ain gas (F ig. 20- 21). Images should be sc rut inized f or ext ension int o t he pelv ic sidew all manif est ed by enc asement of t he iliac v essels and/or separat ion t he v essels f rom t he mass by a f at plane measuring less t han 3 mm in w idt h. Inc reased number and enlargement of pelv ic and ret roperit oneal ly mph nodes should be not ed. CT and MRI are equiv alent in t he det ec t ion of inv olv ed ly mph nodes. Using 1 c m as t he upper limit s of normal, Y ang et al. (106) f ound a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2990

20 - Pelvis 65% ac c urac y w it h CT and a 70% ac c urac y w it h MR. T hic kening of t he ut erosac ral ligament s also manif est s ext ension of disease, alt hough t his c an

also be a result of radiat ion (23). T he dev elopment of hy dronephrosis is of t en t he result of bladder w all or uret eric inv asion and upst ages t he disease t o IIIB. F inally , using CT , a surv ey of t he ot her abdominal organs f or t he presenc e of met ast ases c an be ac c omplished w it hout requiring ext ra sc anning t ime. TABLE 20- 2 STAGING OF ENDOMETRIAL C ARC INOMA TNM C a te gorie s

F IGO Surgic a l Sta ge s

C rite ria Primary t umor c annot be assessed. T0 No ev idenc e of primary t umor. T is 0 Carc inoma in sit u T1 I T umor c onf ined t o c orpus. T 1a Ia T umor limit ed t o endomet rium. T 1b Ib Inv asion of inner half of my omet rium. Ic Inv asion of out er half of my omet rium. T2 II T umor inv ades c erv ix but does not ext end bey ond ut erus. T 2a IIa Cerv ic al st roma not inv aded. T 2b IIb Cerv ic al st roma inv aded. T3 III T umor ext ends bey ond ut erus but not out side t rue pelv is. T 3a IIIa T umor inv ades serosa and/or adnexa; perit oneal c y t ology . T 3b IIIb Vaginal met ast ases. T 3c IIIc Regional ly mph nodes. T4 IVa T umor ext ends out side t rue pelv is or has inv olv ed muc osa of t he bladder or rec t um. M1 IVb Dist ant met ast ases Used w it h t he permission of t he Americ an Joint Commit t ee on Canc er (AJCC), Chic ago. T he original sourc e f or t his mat erial is Greene F L, F leming ID, Page DL, et al., eds. AJCC c anc er st aging m anual, 6t h ed. New Y ork: SpringerVerlag, 2002, ht t p://w w w .springer- ny .c om TABLE 20- 3 STAGING OF OVARIAN C ARC INOMA TX

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2991

20 - Pelvis TNM C a te gorie s

F IGO Sta ge

TX T0 T1

I

T 1a

IA

T 1b

IB

T 1c

IC

T2

II

T 2a

IIA

T 2b

IIB

T 2c

IIC

T3

III

T 3a

IIIA

Computed Body Tomography with MRI Correlation , 4th Edition

C rite ria Primary t umor c annot be assessed. No ev idenc e of primary t umor. T umor limit ed ov aries (one or bot h). T umor limit ed t o one ov ary ; c apsule int ac t , no t umor on ov arian surf ac e. No malignant c ells in asc it es or perit oneal w ashings. T umor limit ed t o bot h ov aries; c apsules int ac t , no t umor on ov arian surf ac e. No malignant c ells in asc it es or perit oneal w ashings. T umor limit ed t o one or bot h ov aries w it h any of t he f ollow ing: c apsule rupt ured, t umor on ov arian surf ac e, malignant c ells in asc it es or perit oneal w ashings. T umor inv olv es one or bot h ov aries w it h pelv ic ext ension and/or implant s. Ext ension and/or implant s on ut erus and/or t ube(s). No malignant c ells in asc it es or perit oneal w ashings. Ext ension and/or implant s on ot her pelv ic t issues. No malignant c ells in asc it es or perit oneal w ashings. Pelv ic ext ension and/or implant s (T 2a or T 2b) w it h malignant c ells in asc it es or perit oneal w ashings. T umor inv olv es one or bot h ov aries w it h mic rosc opic ally c onf irmed perit oneal met ast asis out side t he pelv is. Mic rosc opic perit oneal met ast asis bey ond pelv is

© 2017 Enter your company name

2992

20 - Pelvis

(no mac rosc opic t umor). T 3b IIIB Mac rosc opic perit oneal met ast asis bey ond pelv is 2 c m or less in great est dimension. T 3c IIIC Perit oneal met ast asis bey ond pelv is more t han 2 c m in great est dimension and/or regional ly mph node met ast asis. Used w it h t he permission of t he Americ an Joint Commit t ee on Canc er (AJCC), Chic ago. T he original sourc e f or t his mat erial is Greene F L, F leming ID, Page DL, et al., eds. AJCC c anc er st aging m anual, 6t h ed. New Y ork: SpringerVerlag, 2002, ht t p://w w w .springer- ny .c om

Endometrial Cancer T he most c ommon of t he gy nec ologic malignanc ies, endomet rial c anc er also has t he best prognosis. Of t he 38,000 new c ases diagnosed eac h y ear, 75% of pat ient s present w it h st age I disease c onf ined t o t he endomet rial c anal and c urable by hy st erec t omy (48). Present at ion is usually painless v aginal bleeding in a post menopausal w oman and P.1393 diagnosis is usually made by a c ombinat ion of US and pipet t e biopsy . In addit ion t o age, risk f ac t ors inc lude obesit y and prolonged exposure t o unopposed est rogens. T he endomet rial t hic kness of a post menopausal w oman should not exc eed 5 mm (11). Women w it h bleeding and t hic kened endomet rial linings on US examinat ion merit biopsy . How ev er, ev en in t he presenc e of v aginal bleeding, endomet rial t hic kness of less t han 5 mm exc ludes endomet rial c anc er (11). Women t aking hormone replac ement t herapy or t amoxif en may hav e slight ly t hic ker endomet rial linings and poly ps; how ev er, 5 mm should st ill be t aken as t he upper limit of normal bec ause t hese w omen are at a higher risk f or endomet rial c arc inoma (2,3).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2993

20 - Pelvis

F igure 20- 20 Cerv ic al c anc er, st age IIB. A: Axial c ont rast - enhanc ed c omput ed t omography image at t he lev el of t he kidney s show s no hy dronephrosis. A small ly mph node is present in t he aort oc av al spac e (ar r ow ). B and C : Wit hin t he pelv is an enhanc ing mass f ills and dist ends t he c erv ix (ar r ow s). T here is no ext ension t o t he pelv ic sidew alls and a f at plane is preserv ed bet w een t he c erv ix and t he rec t um.

Most w omen w it h endomet rial c arc inoma do not require imaging. T reat ment is predic at ed on phy sic al examinat ion and low - st age disease c onf ined t o t he endomet rium. Women w it h disease c onf ined t o t he endomet rium or superf ic ial my omet rium hav e a bet t er prognosis t han t hose w it h deep inv asion (10,64). Gy nec ologic onc ologist s rely heav ily on c linic al st aging; how ev er, enlarged ly mph nodes and dept h of primary t umor inv asion may not be apprec iat ed. Creasman et al. (19) rec ent ly report ed t hat , using c linic al st aging, only 35 of 148 (24%) of pat ient s w it h presumed st age II endomet rial c anc er ac t ually had disease c onf ined t o t he ut erus. In t he minorit y of pat ient s, endomet rial c arc inoma w ill present as an obst ruc t ing low er ut erine segment mass w it h assoc iat ed hemat o- or py omet ra. On c ont rast - enhanc ed CT sc ans, t he nodules of t umor usually abut t he w alls of t he dilat ed endomet rial c anal and c omplet ely f ill t he low er ut erine segment (F ig. 20- 22). Met ast ases c an ext end

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2994

20 - Pelvis v ia t he f allopian t ubes t o t he ov aries, c ausing dev elopment of an adnexal

mass. F indings of adv anc ed disease are similar t o t hose of c erv ic al c anc er and c onsist of ext ension of ly mphat ic ext ension of disease t o t he pelv ic sidew all c hains and ret roperit oneum. In c ases in w hic h t hese pat hw ay s are bloc ked by t umor, ext ension v ia t he proc essus v aginalis t o t he inguinal nodes may oc c ur. Perit oneal and mesent eric met ast ases may also oc c ur. T here is a pauc it y of dat a on t he ac c urac y of helic al CT f or t he st aging of endomet rial c anc er. In t he sole published st udy of 25 pat ient s, single det ec t or row helic al CT w as f ound less sensit iv e t han MRI f or t he det ec t ion of deep my omet rial inv asion (42% and 83%, respec t iv ely ) (36). How ev er, in a met a- analy sis perf ormed by Kinkel et al. (56), CT , US, and MRI w ere f ound t o perf orm equally w ell in t he ov erall st aging of endomet rial c anc er. Sarc omas of t he ut erus usually P.1394 P.1395 mimic eit her endomet rial c arc inoma (t w o t hirds) or degenerat ing f ibroids (one t hird) (F ig. 20- 23).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2995

20 - Pelvis F igure 20- 21 Adv anc ed c erv ic al c anc er, st age IIIB. A: Axial c ont rast -

enhanc ed c omput ed t omography image at t he lev el of t he kidney s show s right hy dronephrosis and a diminished nephrogram. B: T he ut erine c anal is obst ruc t ed and f illed w it h f luid (ar r ow ). C : T he c erv ix is markedly enlarged, inv ades t he post erior w all of t he bladder at t he lev el of t he uret erov esic al junc t ion (ar r ow )

F igure 20- 22 Endomet rial c anc er, st age IB. A: Axial c ont rast - enhanc ed c omput ed t omography image of t he pelv is show s abnormal sof t t issue w it h inv asion of t he post erior aspec t of t he my omet rium (ar r ow s). B: T umor is present w it hin a dilat ed endomet rial c anal (ar r ow s). No enlarged ly mph nodes are seen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2996

20 - Pelvis

F igure 20- 23 Leiomy osarc oma. Axial c ont rast - enhanc ed c omput ed t omography images t hrough t he upper abdomen (A) and pelv is (B a nd C ) show numerous low densit y met ast ases w it hin t he liv er (ar r ow s, A) and a large ov oid low densit y mass superior and t o t he lef t of t he ut erus. T he dif f erent ial in t his c ase w ould inc lude an ov arian neoplasm; how ev er, t he pat t ern of met ast at ic disease w ould be ext remely unusual f or a primary t umor of t he ov ary .

Ovarian Cancer Ov arian c anc er is a disease of perimenopausal w omen w it h it s peak bet w een ages 45 and 55 y ears. Approximat ely 23,000 new c ases are ident if ied eac h y ear (48). Risk f ac t ors inc lude a f amily hist ory of ov arian c arc inoma and, in some c ases, breast c anc er. Most t umors are of epit helial origin and are serous or muc inous c y st adenoc arc inomas. Unf ort unat ely , no ef f ec t iv e sc reening examinat ion exist s, and t he majorit y of w omen (60%) present w it h adv anc ed disease ext ending bey ond t he pelv is. A rec ent radiologic diagnost ic onc ologic t rial show ed t hat US, CT , and MRI are equal in t he ov erall st aging of ov arian c anc er, approximat ely 87% t o 95% (59). Bot h CT and MRI hav e exc ellent posit iv e and negat iv e predic t iv e v alues (great er t han 90%) f or t umor resec t abilit y (27). MRI has a slight ly higher det ec t ion rat e f or perit oneal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2997

20 - Pelvis met ast ases. In rout ine prac t ic e, CT is usually pref erred bec ause it is w ell ac c ept ed by t he pat ient and giv es an ov erall v iew of t he abdomen and pelv is

w ell underst ood by ref erring phy sic ians. MRI, how ev er, is part ic ularly usef ul in t he det ec t ion of rec urrent disease bec ause it s t remendous c ont rast sensit iv it y y ields exc ellent ident if ic at ion of ev en v ery small high signal c y st ic implant s on f at - suppressed T 2- w eight ed images. Cy st adenoc arc inoma usually appears on c ont rast - enhanc ed CT images as a large, predominant ly c y st ic mass w it h a nodular, enhanc ing w all and t hic k, enhanc ing sept a. Asc it es, hy dronephrosis, and oment al and perit oneal implant s are c ommon ac c ompaniment s (F ig. 20- 24). Enlarged ly mph nodes are less c ommon but do oc c ur. P.1396 Cy st adenoc arc inoma w it h asc it es and minimal implant f ormat ion is t reat ed w it h an ext ensiv e surgery . T he proc edure c omprises hy st erec t omy , bilat eral salpingo- oophorec t omy , ly mphadenec t omy , asc it es and perit oneal sampling, oment ec t omy , and manual examinat ion of t he surf ac e of t he liv er. On imaging examinat ions, it is import ant t o ident if y solid implant s prior t o t herapy , bec ause a large solid t umor burden is best t reat ed w it h c hemot herapy rat her t han primary debulking surgery (63).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2998

20 - Pelvis

F igure 20- 24 Rec urrent ov arian c arc inoma. Axial c ont rast - enhanc ed c omput ed t omography sc ans at t he lev el of t he upper abdomen (A a nd B) show asc it es rimming t he liv er (ar r ow ) and lef t hy dronephrosis. C : An image of t he pelv is, rev eals a large mixed c y st ic and solid mass f illing t he c ul- de- sac and ext ending int o t he right parac olic gut t er (post er ior ar r ow s). Asc it es is also present in t he lef t gut t er adjac ent t o t he bladder (ant er ior ar r ow ).

Magnetic Resonance Imaging Cervical Cancer Alt hough c erv ic al c anc er has been report ed as being equally w ell ident if ied using bot h t he body and surf ac e c oils and also using low er f ield st rengt h magnet s, lesion c onspic uit y is improv ed using t he surf ac e c oils (108). On MR images, c erv ic al c anc er is usually hy perint ense t o t he dark c erv ic al st roma on T 2- w eight ed images. T he preserv at ion of t he blac k ring of t he c erv ic al st roma, no mat t er how t hin, v irt ually exc ludes paramet rial ext ension. T hese pat ient s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

2999

20 - Pelvis

are c andidat es f or surgic al c ure. T hose in w hom t he blac k line is broken and a mass ext ends bey ond t he expec t ed c onf ines of t he c erv ix hav e an 85% likelihood of paramet rial inv asion and are usually t reat ed primarily w it h brac hy t herapy (41,80,85). It is generally agreed t hat t he administ rat ion of int rav enous Gd- DT PA improv es st aging ac c urac y t o bet w een 85% and 90% (41,81,82). In c ases of adv anc ed disease, sagit t al T 2- w eight ed and/or GdDT PA enhanc ed T 1- w eight ed images w ill show inv asion of t he rec t um, bladder, and v aginal f ornic es (F ig. 20- 25). Ly mph nodes great er t han 1 c m in size are posit iv e f or t umor in 70% of c ases (106). Sev eral small (less t han 1 c m) ly mph nodes in a c hain are also suspic ious f or ext ension of disease.

Endometrial Cancer MRI is rec ommended w hen loc ally adv anc ed disease is expec t ed based on phy sic al examinat ion f indings and in t he pat ient w it h a dif f ic ult phy sic al examinat ion due t o obesit y or prior radiat ion or surgery . Sagit t al and axial T 2w eight ed P.1397 images as w ell as c ont rast - enhanc ed images should be perf ormed and sc rut inized f or ext ension of hy perint ense t umor int o or t hrough t he my omet rium (F ig. 20- 26). Preserv at ion of a subendomet rial band of enhanc ement 120 sec onds post injec t ion of int rav enous c ont rast v irt ually exc ludes my omet rial ext ension (103). In a rec ent met a- analy sis, int rav enous Gd- DT PA w as also show n t o be of signif ic ant v alue in ident if y ing deep inv asion (28). Inv asion of great er t han 50% of t he my omet rium is st rongly indic at iv e of ly mph node met ast ases and a poorer ov erall prognosis. Unf ort unat ely , bec ause of exc ret ion of f luorodeoxy gluc ose int o t he urine and bladder, posit ron emission t omography (PET ) imaging has not y et been prov ed t o be of v alue in det ec t ing adjac ent inv olv ed ly mph nodes (101).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3000

20 - Pelvis

F igure 20- 25 Cerv ic al c arc inoma, st age IIB. A: Sagit t al T 1- w eight ed c ont rast - enhanc ed (147/4.1) magnet ic resonanc e image of t he pelv is show s t he c harac t erist ic barrel shape of a large c erv ic al c arc inoma (ar r ow s). T here is normal enhanc ement of t he st roma surrounding t he t umor; how ev er, t here is ext ension post eriorly int o t he v aginal f ornix. B and C : Axial T 2- w eight ed (90/4.4) images of t he c erv ix show obst ruc t ed high signal ut erine c anal (ar r ow , B), and t umor f illing t he ent iret y of t he c erv ic al c anal (ar r ow , C ). Not e loss of low signal st roma at 5 o'c loc k posit ion.

Ovarian Cancer Alt hough equal t o CT sc anning in ac c urat e st aging of disease, MRI of t he ent ire abdomen and pelv is requires at least 45 minut es. T his c an be dif f ic ult f or an ill pat ient . In addit ion, t he presenc e of asc it es of t en y ields art if ac t s, part ic ularly on t he ult raf ast - pulse sequenc es (F ig. 20- 27). F or t his reason, CT is t he pref erred examinat ion f or st aging of ov arian c anc er. MRI c an be part ic ularly usef ul w hen searc hing f or small- v olume rec urrent disease. It has also been show n t hat rec urrent t umor may be present and v isible on MRI despit e a normal CA- 125 lev el and phy sic al examinat ion (61). Axial f at -

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3001

20 - Pelvis sat urat ed T 2- w eight ed images hav e exquisit e sensit iv it y in det ec t ing small c y st ic implant s.

Magnetic Resonance Imaging of Pelvic Floor Relaxation Approximat ely 50% of parous w omen in t he Unit ed St at es hav e pelv ic f loor relaxat ion, and 20% of t hat group is sy mpt omat ic enough t o seek t reat ment . Sy mpt oms inc lude urinary and f ec al inc ont inenc e and prot rusion of t issue, usually t he c erv ix or ut erus, t hrough t he pelv ic f loor. Pelv ic f loor relaxat ion is usually t he result of a c ombinat ion of P.1398 P.1399 musc le damage and f asc ial st ret c hing or t earing sust ained during c hildbirt h. Most w omen w it h urinary inc ont inenc e c an be diagnosed and t reat ed based on phy sic al examinat ion f indings and of f ic e urody namic s. Pelv ic f loor imaging using MRI is indic at ed w hen mult iple c ompart ment s of t he pelv ic f loor are inv olv ed and prior t o repeat surgeries. It c an also of t en replac e f luorosc opic def ec ography . Sagit t al midline images using an ult raf ast T 2- w eight ed pulse sequenc e w it h t he w oman at rest and at maximal st rain quant if y t he desc ent of all t hree c ompart ment s at onc e and c an be used t o ident if y ent eroc ele, sigmoidoc ele, and ant erior uret hral rot at ion and kinking (F ig. 20- 28). T hin, axial, high- resolut ion T 2- w eight ed images det ail musc le at rophy and t ears. Lat eral dev iat ion of t he v agina usually indic at es a parav aginal f asc ial t ear (24,45).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3002

20 - Pelvis

F igure 20- 26 Endomet rial c arc inoma, st age IA. Axial T 2- w eight ed t urbo spinec ho (T SE) (4902/132) magnet ic resonanc e image of t he ut erus in t he axial (A) and c oronal (B) planes show int ermediat e signal t umor rimming t he endomet rial c anal (ar r ow s). T he low signal junc t ional zone is int ac t (ar r ow heads) indic at ing t hat no inv asion of t he my omet rium has t aken plac e.

F igure 20- 27 Adv anc ed ov arian c anc er. A: Coronal T 2- w eight ed (90/4.4) magnet ic resonanc e (MR) image show s massiv e high signal asc it es and a large, midline, high- signal pelv ic mass (a rrows). Mot ion c auses t he low signal art if ac t seen w it hin t he asc it es. B: Axial image at t he lev el of t he midabdomen using t he same pulse sequenc e demonst rat es int ermediat e sof t t issue solid implant s in t he right parac olic gut t er and replac ing t he oment um (ar r ow s). C : Cont rast - enhanc ed T 1- w eight ed (147/4.1) MR image of t he pelv is show s a large pelv ic mass w it h an int ensely enhanc ing nodular c omponent along t he right ant erior w all (ar r ow ). T he perit oneum is also t hic kened and enhanc es abnormally bright ly , suggest ing dif f use disease.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3003

20 - Pelvis

F igure 20- 28 Pelv ic f loor damage in a middle- aged w oman A: Sagit t al T 2w eight ed half F ourier t urbo spin- ec ho (HAST E) (140/4.5) magnet ic resonanc e (MR) image of t he f emale pelv is obt ained during maximum dow nw ard st rain rev eals a small ant erior rec t oc ele (ar r ow ) as w ell as abnormal c audal angulat ion of t he lev at or plat e (ar r ow head). B: Axial T 2- w eight ed t urbo spinec ho (T SE) (4902/132) MR image show s t hinning of t he right aspec t of t he puborec t alis, t ransec t ion of t he c ompressor uret hrae musc le (ar r ow ) and an abnormal c ont our of t he v agina (ar r ow head). C : Coronal T 2- w eight ed T SE MR image using t he same pulse sequenc e as in B show s t hin, grac ile f ibers of t he usually t hic k band like ilioc oc c y geus (ar r ow s).

Pregnancy

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3004

20 - Pelvis Imaging of t he pregnant mot her or f et us is done only f or t he diagnosis of spec if ic disease ent it ies and f ollow ing a c lear disc ussion of possible risks and benef it s t o t he mot her and f et us. T his disc ussion should inv olv e t he mot her, t he ref erring phy sic ian, and t he radiologist .

Computed Tomography In t he c ase of signif ic ant mat ernal t rauma, c ont rast - enhanc ed CT sc an is t he t est of c hoic e. It c an be done quic kly and is ext remely reliable in t he det ec t ion of hemoperit oneum and v isc eral injury (F ig. 20- 29). T he most c ommon c ause of f et al deat h is mat ernal deat h, f ollow ed by plac ent al abrupt ion. All sc an paramet ers should be rec orded and giv en t o t he depart ment al phy sic ist , w ho w ill P.1400 t hen make an est imat e of mat ernal dose. In general, a dose of great er t han 10 rads should generat e a c onsiderat ion of abort ion in a f irst t rimest er pregnanc y (35). CT may also be used t o diagnose obst ruc t ing mat ernal uret eral st ones, part ic ularly in t he t hird t rimest er w hen t he absorbed dose t o t he f et us dec reases signif ic ant ly .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3005

20 - Pelvis

F igure 20- 29 T rauma in early pregnanc y . A, B, and C : Axial c ont rast enhanc ed c omput ed t omography sc ans show a large amount of high- densit y blood w it hin t he upper and mid aspec t s of t he abdomen. At surgery , a rupt ured splenic art ery aneury sm w as ident if ied (ar r ow , A). C : Mild enlargement of t he f irst t rimest er ut erus (ar r ow s, C ).

Magnetic Resonance Imaging MRI is of t en request ed f or ev aluat ion of mat ernal pat hology ranging f rom headac hes and bac k pain t o c anc er st aging. Alt hough no t erat ogenic ef f ec t s hav e been report ed sec ondary t o pulse sequenc es rout inely used in human imaging, it is st ill prudent t o disc uss t he possible mat ernal benef it s and t he unknow n long- t erm risk of MRI t o t he f et us. One of t he more c ommon request s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3006

20 - Pelvis

is t he c harac t erizat ion of a mat ernal pelv ic mass ident if ied on US examinat ion. In most c ases, imaging should be done in t he sec ond t rimest er bec ause t he c orpus lut eum c y st has resolv ed and it is t he opt imal t ime f or surgery . T he radiologist should monit or all sc ans. Pulse sequenc es should be kept t o a minimum and Gd- DT PA administ ered only w hen absolut ely nec essary (49). It is c rit ic ally import ant t hat t he origin of any mass be ident if ied (F ig. 20- 30). A pedunc ulat ed f ibroid w ill be lef t in plac e, w hereas a presumed ov arian malignanc y w ill be operat iv ely remov ed (52,67). MRI should also be t he t est of c hoic e w hen st aging c anc er in t he abdomen and pelv is. Det ec t ion rat es f or liv er met ast ases and enlarged ly mph nodes are approximat ely equal t o t hose of CT and no ionizing radiat ion P.1401 is inv olv ed, alt hough int rav enous administ rat ion of Gd- DT PA w ill likely be required.

F igure 20- 30 Appendic it is in a pregnant w oman. A and B: Axial T 1- w eight ed (147/4.1) c ont rast - enhanc ed magnet ic resonanc e images at t w o lev els in t he abdomen show f luid c ollec t ion w it h an enhanc ing rim in t he right parac olic gut t er (ar r ow ) diagnost ic of an absc ess. Inf erior t o t he f luid c ollec t ion is an int ensely enhanc ing t ubular st ruc t ure, t he inf lamed appendix (ar r ow ).

CT and MRI are bot h usef ul in t he peripart um st at e. F low sensit iv e gradient ec ho MRI pulse sequenc es t hrough t he pelv is are a part ic ularly f ast and ac c urat e w ay t o exc lude pelv ic or ov arian v ein t hrombosis (97). CT sc an is usually t he t est of c hoic e f or ident if ic at ion of absc ess sec ondary t o endomet rit is or w ound inf ec t ion. T his usually appears as an enlarged ut erus w it h gas inside t he ut erine c av it y and ext ensiv e st randing of adjac ent f at . T he ov ary and f allopian t ube may also be inv olv ed similar t o a t uboov arian

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3007

20 - Pelvis

absc ess. MRI is part ic ularly usef ul in imaging gest at ional t rophoblast ic disease. T his appears as a dist ended ut erine c av it y c ont aining a relat iv ely high T 2 signal mass t hat of t en inv ades t he my omet rium (7).

Fetal Anomalies Wit h t he adv ent of ult raf ast T 2- w eight ed pulse sequenc es suc h as HAST E and SSF SE, it has bec ome possible t o image t he f et us w it hout t he blurring assoc iat ed w it h mot ion. An MR image is f irst obt ained parallel t o t he f et al spine. Eac h set of images t hen serv es as t he sc out f or t he next , inc luding f et al axial and c oronal planes. Alt hough US remains t he mainst ay in t he det ec t ion of f et al anomalies, MR has prov ed of v alue in c onf irming v isc eral and musc uloskelet al anomalies and ident if y ing c ranial anomalies (F ig. 20- 31). Imaging is usually done as part of a c omplet e c linic al w orkup in a w oman know n t o c arry a sec ond t rimest er f et us w it h an abnormal kary ot y pe or US (60). T he most c ommon indic at ion is my elomeningoc ele. F indings c an be used t o plan f or in ut er o surgery or t o c ounsel parent s on prognosis and t he need f or f urt her genet ic t est ing.

F igure 20- 31 Pot t er's sy ndrome in a t hird t rimest er f et us. Sagit t al T 2w eight ed half F ourier t urbo spin- ec ho (HAST E) (147/4.1) image parallel t o t he long axis of t he f et us in v ert ex posit ion demonst rat es sev ere oligohy dramnios (ar r ow s). Kidney s w ere not ident if ied on any projec t ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3008

20 - Pelvis P.1402

NEOPLASMS OF THE MALE PELVIS CT and MR prot oc ols f or t he male pelv is are t he same as t hose f or t he f emale pelv is. Canc ers of t he t est es and prost at e are primarily ident if ied using US. CT and MRI are reserv ed f or st aging of disease. F or CT imaging, bot h oral and int rav enous c ont rast media should be administ ered in all c ases. In MRI of t he prost at e, int rav enous administ rat ion of Gd- DT PA is nec essary only w hen seminal v esic le ext ension is suspec t ed. Rec ent ly , some aut hors hav e report ed t he v alue of ult rasmall paramagnet ic iron part ic les in t he ident if ic at ion of ly mph nodes inv olv ed w it h prost at e c anc er; how ev er, t hese hav e not y et been approv ed f or human use by t he U.S. F ood and Drug Administ rat ion (38,39).

Prostate Carcinoma Prost at e adenoc arc inoma is primarily a disease of t he elderly male. Approximat ely 200,000 new c ases are diagnosed eac h y ear (48). It is usually det ec t ed by an elev at ed (great er t han 4 ng/dL) prost at e- spec if ic ant igen (PSA) or abnormal digit al rec t al examinat ion. T ransrec t al US is t hen used t o direc t biopsy of suspic ious, hy poec hoic regions, usually in t he peripheral zone. Bec ause of t he high inc idenc e of mult if oc alit y , sext ant biopsies are perf ormed. Pat hologic spec imens are graded using t he Gleason sc ale, w hic h is t he sum of t he most prev alent and sec ond most prev alent t y pes of dy splasia, eac h on a sc ale of 1 t o 5, w it h 5 being t he most dy splast ic . In general, pat ient s w it h a Gleason grade of less t han 7 and a PSA of less t han 10 ng/L are c onsidered t o hav e pot ent ially c urable disease. T hese pat ient s undergo prost at ec t omy , brac hy t herapy , or ext ernal beam radiat ion. Pat ient s t hat do not meet t hese c rit eria w ill usually undergo a c ombinat ion of hormone t herapy and ext ernal beam radiat ion. T he T NM st aging sy st em f or prost at e c anc er is list ed in T able 20- 4.

Computed Tomography In most inst it ut ions, no pelv ic imaging is perf ormed prior t o radic al prost at ec t omy . CT sc ans of t he abdomen and pelv is are ordered prior t o t he onset of radiat ion t herapy t o ident if y bony landmarks f or planning. At t he same t ime, t he abdomen and pelv is c an be sc reened f or c omorbidit ies, alt hough t his has been show n t o be an ext remely low y ield proc edure (26). In

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3009

20 - Pelvis adv anc ed disease, CT sc an is t he t est of c hoic e t o ident if y enlarged pelv ic and ret roperit oneal ly mph nodes and hy dronephrosis (F ig. 20- 32). Images should be examined using bone w indow s f or t he presenc e of ost eoblast ic met ast ases, part ic ularly in t he low er lumbar spine. TABLE 20- 4 STAGING OF PROSTATE C ANC ER T —Primary t umor Clinic al TX T0 T1 T 1a T 1b T 1c T2 T 2a T 2b T 2c T3 T 3a T 3b T4

N—Regional ly mph nodes Clinic al NX

Primary t umor c annot be assessed. No ev idenc e of primary t umor. Clinic ally inapparent t umor neit her palpable nor v isible by imaging. T umor inc ident al hist ologic f inding in 5% or less of t issue resec t ed. T umor inc ident al hist ologic f inding in more t han 5% of t issue resec t ed. T umor ident if ied by needle biopsy (e.g., bec ause of elev at ed PSA). T umor c onf ined w it hin prost at e. T umor inv olv es one half of one lobe or less. T umor inv olv es more t han one half of one lobe but not bot h lobes. T umor inv olv es bot h lobes. T umor ext ends t hrough t he prost at e c apsule. Ext rac apsular ext ension (unilat eral or bilat eral). T umor inv ades seminal v esic le(s). T umor is f ixed or inv ades adjac ent st ruc t ures ot her t han seminal v esic les: bladder nec k, ext ernal sphinc t er, rec t um, lev at or musc les, and/or pelv ic w all.

Regional ly mph nodes w ere not assessed. No regional ly mph node met ast asis. Met ast asis in regional ly mph node(s).

N0 N1 PSA, prost at e- spec if ic ant igen. Used w it h t he permission of t he Americ an Joint Commit t ee on Canc er (AJCC), Chic ago. T he original sourc e f or t his mat erial is Greene F L, F leming ID, Page DL, et al., eds. AJCC c anc er st aging m anual, 6t h ed. New Y ork: SpringerVerlag, 2002, ht t p://w w w .springer- ny .c om

Magnetic Resonance Imaging

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3010

20 - Pelvis Small f ield- of - v iew , T 2- w eight ed MRI, using a mult ic oil array or an endorec t al c oil, or bot h, c an be of v alue in t he pat ient w it h c onf lic t ing signs and sy mpt oms, suc h as a high PSA and a small, smoot h prost at e (17,82). On T 2w eight ed F SE images prost at e c anc er usually appears as a region of low t o int ermediat e signal w it hin t he peripheral zone. Most signif ic ant c anc ers oc c ur along t he post erior port ion of t he gland at t he 5 and 7 o'c loc k posit ions. Direc t ext ension of disease t hrough t he low T 2- signal c apsule is indic at iv e of ext rac apsular ext ension and likely inc urable disease. Images should also be sc rut inized f or asy mmet ry of t he neurov asc ular bundles, oblit erat ion of t he

rec t oprost at ic angle, inv olv ement of t he uret hra at t he apex of t he gland, and ext ension int o t he seminal v esic les (F ig. 20- 33) (107). P.1403 An experienc ed reader w ill ac c urat ely st age prost at e c arc inoma in 68% of c ases (93). Ly mph node met ast ases c an be seen if t he inv olv ed nodes are enlarged. Ly mphadenopat hy is best apprec iat ed on T 1- w eight ed images. Unf ort unat ely , t issue c harac t erizat ion based on MR signal is not possible. Ly mphadenopat hy f rom benign c auses c annot be dist inguished f rom malignant disease. T he abilit y t o det ec t small nodal met ast asis is signif ic ant ly improv ed w it h MR ly mphangiography t hat uses an int rav enous c ont rast agent c onsist ing of ult rasmall super paramagnet ic iron oxide part ic les (USPIO). In one phase III c linic al t rial of pat ient s w it h prost at e c arc inoma (39), post - USPIO P.1404 MRI had a sensit iv it y of 90.5% in det ec t ing met ast asis in ly mph nodes bet w een 5 t o 10 mm in size (v ersus 35% f or nonc ont rast sc ans) and a sensit iv it y of 41% in nodes less t han 5 mm in size (v ersus 0% f or nonc ont rast sc ans). F ollow ing radic al prost at ec t omy , pat ient s w it h elev at ed PSA should be examined using MRI. Similar t o t he pat ient st at us post abdominoperineal resec t ion, v iew ing t he pelv ic f loor w it h high- c ont rast T 2- w eight ed or c ont rast - enhanc ed images makes it muc h easier t o separat e t umor f rom normal t issue (87). CT and MR images c an also be of v alue in diagnosing inf lammat ory proc esses of t he prost at e and adjac ent organs. Prost at e absc ess is usually sec ondary t o inf ec t ion, w it h eit her Chlam y dia or Neisser ia gonor r hoeae in t he sexually ac t iv e or Esc her ic hia c oli in t he elderly w it h prost at ic out let obst ruc t ion. T he normal gland is replac ed w it h low - densit y f luid on CT sc ans or high T 2- signal f luid t hat of t en f orms mult iple absc esses and ext ends int o t he adjac ent seminal v esic les. T reat ment is generally int rav enous P.1405

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3011

20 - Pelvis ant ibiot ic s and inc ision and drainage, usually v ia a t ransrec t al rout e (F ig. 2034).

F igure 20- 32 Adv anc ed prost at e c anc er. A: Axial c ont rast - enhanc ed c omput ed t omography image t hrough t he lev el of t he kidney s show s right ret roperit oneal ly mphadenopat hy (ar r ow head) and lef t hy dronephrosis (ar r ow ). B: At a low er lev el, t umor has inv aded t he bladder w all and seminal v esic le (ar r ow )

F igure 20- 33 Adv anc ed prost at e c anc er. A: Coronal T 2- w eight ed f ast spinec ho (F SE) image (4000/108) of t he prost at e obt ained using an endorec t al c oil show s dif f use abnormal low signal t hroughout t he peripheral zone. T hese are mult iple sit es of adenoc arc inoma. T he ejac ulat ory duc t s are also t hic kened (ar r ow s). B: Axial T 2- w eight ed F SE image using t he same pulse sequenc e as in A show s t hic kening of t he normally grac ile seminal v esic le

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3012

20 - Pelvis sept a indic at ing t umor inv asion (ar r ow s). (Images c ourt esy of Dr. Clare T empany , Bost on, MA.)

F igure 20- 34 Prost at e absc ess. A: Axial non- c ont rast - enhanc ed c omput ed t omography sc an of t he low er pelv is perf ormed t o diagnose presumed renal c olic show s an enlarged prost at e gland c ont aining low - densit y areas (ar r ow s). B: Coronal T 1- w eight ed c ont rast - enhanc ed (147/4.1) magnet ic resonanc e (MR) image demonst rat es normal appearanc e of t he kidney s w it h exc ept ion of a f ew c y st s and a mult isept at ed mass replac ing t he majorit y of t he prost at e (ar r ow s). C : Axial image obt ained using t he same paramet ers as B bet t er def ines t he inf lammat ory mass t hat replac es t he prost at e, displac es t he uret hra t o t he right (ar r ow head) and ext ends int o t he lef t seminal v esic le (ar r ow ). D: Axial T 2- w eight ed t urbo spin- ec ho (T SE) (4902/132) MR image at t he same lev el as C demonst rat es ext ensiv e f at st randing radiat ing post eriorly f rom t he lef t side of t he prost at e (ar r ow ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3013

20 - Pelvis

F igure 20- 35 Prost at e c anc er. Axial T 2- w eight ed t urbo spin- ec ho (T SE) (4902/132) magnet ic resonanc e image of t he prost at e show s an enlarged c ent ral zone t hat v irt ually oblit erat es t he peripheral zone. Prev ious biopsies had demonst rat ed dif f use int ermediat e grade c arc inoma. Spec t ra obt ained w it hin t he peripheral zone (box) show elev at ed c holine lev els c orrelat ing w it h t he presenc e of c arc inoma.

T he addit ion of spec t rosc opy t o f ast T 2- w eight ed imaging is a new area of researc h t hat holds signif ic ant promise f or t he det ec t ion of primary and rec urrent disease. A v irt ual grid is superimposed on a 3D ac quisit ion and nuc lear magnet ic resonanc e spec t ra obt ained w it hin eac h square of t issue (F ig. 20- 35). T he normal prost at e produc es a large of amount of c it rat e f rom t he peripheral zone. T umors do not produc e c it rat e. Using t he MR spec t ra, elev at ed c holine- t o- c it rat e rat ios c an be used t o ident if y sit es of t umor (58).

F igure 20- 36 T est ic ular c anc er. A and B: Axial c ont rast - enhanc ed c omput ed t omography images of t he abdomen show large ly mph nodes at t he lev el of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3014

20 - Pelvis lef t renal hilum (ar r ow s) part ially enc ase aort a (A). B: T he pat ent renal v ein is draped ant eriorly ov er t he enlarged ly mph nodes (ar r ow heads). (Images c ourt esy of Dr. Jef f rey Klein, Williamsburg, VA.)

Testicular Cancer Computed Tomography T est ic ular malignanc ies oc c ur predominant ly in y oung men and are relat iv ely unc ommon w it h approximat ely 7,000 new c ases diagnosed eac h y ear (48). T hese malignanc ies are almost alw ay s diagnosed by a c ombinat ion of phy sic al examinat ion and US. T umors are div ided int o t he more c ommon seminomat ous t umors and t he relat iv ely rare germ c ell t umors. T he majorit y of t umors are mixed c ell t y pe w it h seminoma predominant and smaller amount s of ot her c ell t y pes inc luding y olk sac , embry onal c ell, and t erat oma. F ollow ing t he st andard t reat ment of orc hiec t omy , c ont rast - enhanc ed CT sc ans of t he abdomen and pelv is are perf ormed t o searc h f or met ast at ic disease. T he ly mphat ic drainage of t he t est ic les is t o t he renal hila. Sec ondary drainage t o t he aort oiliac bif urc at ion also oc c urs, part ic ularly on t he right . Inv olv ed ly mph nodes are of sof t t issue densit y w it h dense enhanc ement (F ig. 20- 36). T he enlarged nodes may enc ase t he renal v essels and c ompress and oc c asionally inv ade t he inf erior v ena c av a (IVC). Part ic ularly large and low - densit y nodes indic at e t he presenc e of t erat oma. Unf ort unat ely , node densit y does not c orrelat e w it h t he degree of c ell kill f ollow ing c hemot herapy . Residual c y st ic appearing nodes of t en undergo surgic al dГ©bridement t o maximize pot ent ial f or c ure. On f ollow - up sc ans, all nodes great er t han 5 mm are c onsidered suspic ious f or met ast asis (44). Imaging f indings should be c orrelat ed w it h bioc hemic al t umor markers t o f urt her direc t t herapy . P.1406

Magnetic Resonance Imaging Magnet ic resonanc e imaging is rarely perf ormed f or t he primary diagnosis of t est ic ular c anc er. T 2- w eight ed MRI, using a loop or shoulder c oil plac ed ov er t he sc rot um, c an be usef ul in ident if y ing masses w hen US is indet erminat e. T umors appear as low - signal masses w it hin t he normal v ery high T 2- signal int ensit y t issue. It is dif f ic ult t o ident if y c alc if ic at ions; how ev er, c apsular inv olv ement c an of t en be det ermined.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3015

20 - Pelvis Undescended Testes During embry ogenesis t he t est es migrat e f rom t he lev el of t he kidney s

inf eriorly and t hrough t he inguinal c anal int o t he sc rot um. When a t est ic le f ails t o desc end properly , it is loc at ed w it hin t he inguinal c anal 90% of t he t ime. In c hildren, US is of t en used t o make t his diagnosis and an orc hiopexy is perf ormed. In t he adult present ing w it h an empt y sc rot um, t hin- sec t ion CT or T 2- w eight ed MR images ext ending f rom t he lev el of t he kidney s t o t he sc rot um should be perf ormed. On CT sc ans, t he t est ic le appears as a small almondshaped sof t t issue densit y st ruc t ure along t he migrat ion pat h (F ig. 20- 37) (29). On MR images, t he t est ic le is of v ariable signal int ensit y . In y oung adult s and w hen f ert ilit y remains an issue, an orc hiopexy w ill be perf ormed. When t he pat ient is older t han 35 y ears, t he undesc ended t est ic le is usually remov ed. All prev iously undesc ended t est ic les are at risk f or sarc omat ous t ransf ormat ion and must be monit ored f or c hange in size, usually by phy sic al examinat ion.

F igure 20- 37 Undesc ended t est ic le. Axial T 2- w eight ed half F ourier t urbo spin- ec ho (HAST E) (90/4.5) image show s a high signal ov oid t est ic le w it hin t he right inguinal c anal (ar r ow ).

PELVIC NEOPLASMS COMMON TO BOTH SEXES Bladder Cancer More t han 50,000 new c ases of bladder c anc er are diagnosed eac h y ear, t he majorit y in males older t han 60 y ears (48). Risk f ac t ors inc lude smoking, c hronic inf ec t ion, and exposure t o aromat ic amines and c y c lophosphamide.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3016

20 - Pelvis P.1407 Ninet y - f iv e perc ent of bladder t umors are t ransit ional c ell c arc inomas, w it h t he rest c omprising a mix of squamous c ell c arc inoma, adenosquamous c ell c arc inoma, and t he rare sarc oma. Sev ent y perc ent of bladder c anc ers are

superf ic ial in origin. Pat ient s do not usually require imaging bec ause disease is t reat ed c y st osc opic ally w it h f ulgurat ion, snaring, and t opic al c hemot herapy . Some radiologic groups hav e experiment ed w it h v irt ual c y st osc opy using CT images of an air- f illed bladder; how ev er, t his is not y et ac c ept ed as rout ine prac t ic e (25,89). T he remaining 30% of bladder c anc ers are inv asiv e w hen disc ov ered. T o det ermine w het her a pot ent ially c urat iv e c y st ec t omy should be at t empt ed, t he surgeon needs t o know w het her t he disease is c onf ined t o t he bladder w all (st age II) or ext ends int o t he periv esic al f at (st age III). T his is done using a c ombinat ion of c y st osc opic biopsy and CT or MRI. T he T NM st aging sy st em f or bladder c anc er is present ed in T able 20- 5. TABLE 20- 5 STAGING OF URINARY BLADDER C ANC ER Primary t umor (T ) TX T0 Ta T is T1 T2 pT 2a pT 2b T3 pT 3a pT 3b T4

T 4a T 4b

Primary t umor c annot be assessed. No ev idenc e of primary t umor. Noninv asiv e papillary c arc inoma. Carc inoma in sit u: “ f lat t umor.” T umor inv ades subepit helial c onnec t iv e t issue. T umor inv ades musc le. T umor inv ades superf ic ial musc le (inner half ). T umor inv ades deep musc le (out er half ). T umor inv ades periv esic al t issue. Mic rosc opic ally . Mac rosc opic ally (ext rav esic al mass). T umor inv ades any of t he f ollow ing: prost at e, ut erus, v agina, pelv ic w all, abdominal w all. T umor inv ades prost at e, ut erus, v agina. T umor inv ades pelv ic w all, abdominal w all.

Regional ly mph modes (N) Regional ly mph nodes are t hose w it hin t he t rue pelv is; all ot hers are dist ant ly mph nodes. NX Regional ly mph nodes c annot be assessed. N0 No regional ly mph node met ast asis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3017

20 - Pelvis N1 N2

N3

Met ast asis in a single ly mph node, 2 c m or less in great est dimension. Met ast asis in a single ly mph node, more t han 2 c m but not more t han 5 c m in great est dimension; or mult iple ly mph nodes, none more t han 5 c m in great est dimension. Met ast asis in a ly mph node, more t han 5 c m in great est dimension.

Dist ant met ast asis (M) MX

Dist ant met ast asis c annot be assessed. M0 No dist ant met ast asis. M1 Dist ant met ast asis. Used w it h t he permission of t he Americ an Joint Commit t ee on Canc er (AJCC), Chic ago. T he original sourc e f or t his mat erial is Greene F L, F leming ID, Page DL, et al., eds. AJCC c anc er st aging m anual, 6t h ed. New Y ork: SpringerVerlag, 2002, ht t p://w w w .springer- ny .c om

F igure 20- 38 Bladder c anc er w it h c omput ed t omography urogram (CT U). A and B: Axial c ont rast - enhanc ed images w it h ext rinsic c ompression dev ic e in plac e show (A) normal sy mmet ric enhanc ement of kidney s and normal appearanc e of int rarenal c ollec t ing sy st ems (ar r ow s) and (B) a large mass arising f rom t he right ant erior bladder w all (ar r ow s). T here is assoc iat ed st randing of t he periv esic al f at suggest ing inv asion and adv anc ed disease (ar r ow heads). C : A c oronal ref ormat t ed image 5 mm in t hic kness again show s t he bladder mass arising f rom t he right aspec t of t he w all. T he int rarenal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3018

20 - Pelvis c ollec t ing sy st ems and bot h uret ers w ere enhanc ed and ident if ied on ot her c oronal images.

Computed Tomography CT should be perf ormed using oral and int rav enous c ont rast w it h t hin sec t ions t hrough t he bladder w it h bot h a 70- sec ond and a 5- minut e delay . T he early images w ill serv e t o demonst rat e hy perv asc ular areas of t umor and t he lat er images are somet imes v aluable in out lining t he t umor ext ent along t he w all surf ac e. T umors may be poly poid or sessile and of t en ext end t o inv olv e a large area of t he bladder w all, inc luding t he uret erov esic al junc t ion. Bec ause t ransit ional c ell c arc inoma is of t en mult if oc al, ev aluat ion of t he ent iret y of t he urot helial t rac t should be at t empt ed. Using mult idet ec t or CT sc ans w it h rapid ref ormat t ing, P.1408 c oronal images c an be used t o c hec k t he renal pelv es and uret ers f or t he presenc e of st ric t ures and masses (F ig. 20- 38). It is not know n w het her t he spat ial resolut ion of ref ormat t ed CT sc ans images is adequat e f or ident if ic at ion of v ery small uret eral t umors, alt hough rec ent w ork suggest s t his may be t he c ase (15). F ort unat ely , only 1% of t ransit ional c ell c arc inoma oc c urs primarily in t he uret er. All images should also be ev aluat ed f or t he presenc e of inc reased number and size of pelv ic and ret roperit oneal ly mph nodes and dist ant disease (F ig. 20- 39). In c ases of adv anc ed disease, CT is probably pref erred bec ause of it s rapid ac quisit ion and ease of int erpret at ion. Bec ause post biopsy inf lammat ory c hanges in t he periv esic al f at c an mimic t umor, a def init e diagnosis of periv esic al ext ension of t umor c an somet imes be dif f ic ult t o make. Def init iv e diagnosis of st age III disease is possible w hen an enhanc ing mass is present .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3019

20 - Pelvis

F igure 20- 39 Adv anc ed bladder c anc er. A: Axial c ont rast - enhanc ed c omput ed t omography image at t he lev el of t he kidney s show s right hy dronephrosis w it h a diminished nephrogram as w ell as a lef t renal c y st . B and C : Images of t he pelv is show enlarged right ext ernal iliac ly mph nodes (ar r ow , B) and a small bladder mass inv olv ing t he right uret erov esic al junc t ion (ar r ow heads, C ).

Magnetic Resonance Imaging On T 2- w eight ed MRI, t he musc ular w all of t he bladder is of homogeneously dark signal. Ext ension int o but not t hrough t he musc ular w all is St age II disease (F ig. 20- 40). Ext ension of high signal mass t hrough t he w all indic at es St age III disease. Met ast asis t o a ly mph node c an be rec ognized if it leads t o nodal enlargement (F ig. 20- 41). Using 1.5 T sy st ems and Gd- DT PA int rav enous c ont rast agent , ov erall st aging ac c urac y is approximat ely 85% (6,42). F or loc al ext ension, T 1- w eight ed, dy namic , post - Gd- DT PA enhanc ed images may be of help in delineat ing a mass f rom adjac ent inf lammat ory st randing. Coronal images of t he upper urinary t rac t , similar t o t hose w it h CT or int rav enous urography (IVU), c an be obt ained using a heav ily T 2- w eight ed c oronal series,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3020

20 - Pelvis obt ained eit her as a v olume or c omprising mult iple slic es. MRI has also been adv oc at ed f or assessing response t o c hemot herapy , w it h delay ed P.1409 enhanc ement of responding ly mph nodes ident if ied af t er f our c y c les of met hot rexat e, v inblast ine, adriamy c in, and c isplat in (5).

F igure 20- 40 Mult if oc al superf ic ial bladder c anc er. A: Sagit t al T 2- w eighed half F ourier t urbo spin- ec ho (HAST E) (90/4.5) magnet ic resonanc e image of t he bladder show s mult iple int ermediat e signal masses arising f rom t he w all (ar r ow s). T he low signal musc ular w all appears int ac t in t his image (ar r ow heads), suggest ing t hat t hese are superf ic ial t y pe t umors. B: Using t he same pulse sequenc e in an axial plane, t he musc ular w all again appears int ac t . T he lef t post erior aspec t of t he w all w as seen t o bet t er adv ant age on ot her images.

An unusual t umor of t he pelv is arises f rom t he urac hal remnant . T his t umor, loc at ed at t he bladder dome, is usually an adenoc arc inoma. T he c lassic , alt hough unc ommon, c linic al present at ion is t hat of muc us in t he urine. Appearanc e on CT and MR images is t hat of a solid, enhanc ing mass arising f rom t he bladder dome (F ig. 20- 42). T umor may ext end superiorly and ant eriorly t ow ard t he umbilic us. Dif f erent ial diagnosis inc ludes an urac hal absc ess and t reat ment is alw ay s surgic al.

Recurrent Colorectal Cancer Following Abdominoperineal Resection

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3021

20 - Pelvis Aggressiv e rec t al c anc ers are t reat ed w it h surgic al resec t ion, c losure of t he rec t um, and t he f ormat ion of a c olost omy . T he pelv ic f loor is of t en pac ked w it h f at , somet imes obt ained f rom t he oment um. T he remaining pelv ic organs rot at e post eriorly and desc end inf eriorly , signif ic ant ly c hanging t heir

appearanc e on c ross- sec t ional imaging. In males, on axial images t he prost at e is of t en heart shaped w it h t he apex direc t ed at t he sy mphy sis. T he seminal v esic les ext end post eriorly and c an be mist aken f or t umor. In t he f emale, similar c hanges oc c ur w it h desc ent and rot at ion of t he ut erus. T he ov aries usually remain loc at ed lat erally w it hin t he pelv is.

Computed Tomography F ollow ing abdominoperineal resec t ion, it is c ommon t o see sof t t issue densit y w it hin t he presac ral spac e. When t his mat erial remains plaque- like, f ibrosis is likely . T he dev elopment of an enhanc ing rounded solid or nec rot ic mass is of t en indic at iv e of rec urrent disease (F ig. 20- 43). PET sc anning or biopsy should t hen be perf ormed.

Magnetic Resonance Imaging T 2- w eight ed MRI of f ers high- c ont rast dif f erent iat ion bet w een residual f at and bow el f rom rec urrent usually int ermediat e t o high- signal disease. Rec urrent disease usually oc c urs as a mass at t he resec t ion sit e near t he pelv ic f loor and demonst rat es enhanc ement on Gd- DT PA–enhanc ed images w it hin t he f irst 90 sec onds post injec t ion (55,57). P.1410 P.1411 It is import ant t o assess t he adjac ent musc les and perit oneal surf ac es f or abnormal, inc reased enhanc ement , w hic h usually indic at es ext ension of disease bey ond t he presac ral spac e (F ig. 20- 44).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3022

20 - Pelvis

F igure 20- 41 Adenoc arc inoma of t he bladder. A: T ransaxial T 1- w eight ed SE image (600/15) show s a mass (ar r ow ) slight ly hy perint ense t o urine arising f rom t he ant erior bladder w all and ext ending int o t he periv esic al f at . B: T he mass (st r aight ar r ow ) is hy perint ense t o normal bladder w all (c ur v ed ar r ow ) on t his T 2- w eight ed SE image (2500/90). C : T ransaxial T 1- w eight ed SE image (600/15) sev eral c ent imet ers c ephalad show s right ext ernal iliac adenopat hy . T he nodal mass (blac k ar r ow ) c an be dist inguished easily f rom adjac ent highsignal f at and f low v oids of t he iliac v essels (w hit e ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3023

20 - Pelvis

F igure 20- 42 Urac hal c arc inoma. Axial c ont rast - enhanc ed c omput ed t omography image at t he lev el of t he bladder dome show s an enhanc ing mass (ar r ow ). Alt hough t hese t umors of t en appear t o be loc ally c onf ined, t he prognosis is ext remely poor and t he v ast majorit y of pat ient s suc c umb t o met ast at ic disease.

F igure 20- 43 Rec urrent rec t al c anc er f ollow ing abdominoperineal resec t ion. Axial c ont rast - enhanc ed c omput ed t omography images of t he pelv is (A and B) show t he bladder t o be displac ed post eriorly and t o c ont ain a lef t uret eral st ent (ar r ow heads, A). A round mass loc at ed in t he presac ral spac e (ar r ow s, B) w as lat er biopsied and f ound t o be rec urrent disease. T his c ould also hav e been c onf irmed using posit ron emission t omography imaging.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3024

20 - Pelvis OTHER ABNORMALITIES OF THE TREATED PELVIS Surgic al and radiat ion t herapy c auses numerous abnormalit ies in t he pelv is. T he majorit y of t hese c an be ident if ied using eit her CT or MRI. F indings assoc iat ed w it h radiat ion t herapy inc lude bright enhanc ement of t he perit oneum, t hic kening and t et hering of large and small bow el loops, and t hic kening of t he bladder w all and ut erosac ral ligament s (46). Sof t t issue edema of t he presac ral spac e, pelv ic musc les, and subc ut aneous f at may persist f or up t o 18 mont hs post t reat ment (9). Uret eral dilat ion may be f ound in up t o 50% of c ases (8). Radiat ion may also c ause f at t y replac ement and t hinning of t he py rif ormis musc le, y ielding inc reased T 2 signal on MR images. Assoc iat ed damage t o t he sc iat ic nerv e w it h result ing leg pain is somet imes c alled py rif ormis sy ndrome.

F ist ula f ormat ion bet w een t he bow el and bladder or, in t he c ase of t he f emale, c erv ix or v agina and bladder are unc ommon but dev ast at ing c omplic at ions of surgic al or radiat ion t herapy . T hese c an be ident if ied using eit her int rav enous or oral c ont rast , but not simult aneously , and demonst rat ing ext ension of c ont rast f rom one organ t o t he ot her (43) (F ig. 20- 45).

F igure 20- 44 Rec urrent rec t al c anc er f ollow ing surgic al resec t ion. A: Sagit t al T 2- w eight ed half F ourier t urbo spin- ec ho (HAST E) (90/4.5) image of t he pelv is show s an int ermediat e signal int ensit y mass (ar r ow ) just inf erior and post erior t o t he bladder. B: Axial T 1- w eight ed c ont rast - enhanc ed image of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3025

20 - Pelvis presac ral mass (ar r ow s) demonst rat es it t o be inseparable f rom t he seminal v esic les.

P.1412 F inally , f luid c ollec t ions may result f rom t herapy inc luding seromas, urinomas, ly mphoc eles, and absc esses. Seromas and urinomas hav e no c ent ral and minimal peripheral enhanc ement . No air bubbles are seen w it hin t hem. Large ly mphoc eles most c ommonly oc c ur f ollow ing c y st ec t omy or prost at ec t omy . T hey usually c ont ain grac ile sept a and ext end int o t he ret roperit oneum. Absc esses c ont ain f luid densit y mat erial and of t en hav e a t hic k, enhanc ing w all. Small air poc ket s, many of t hem dependent , may also be present (F ig. 20- 46).

F igure 20- 45 Rec urrent rec t al t umor w it h f ist ula f ormat ion. A: Axial T 1w eight ed c ont rast - enhanc ed image demonst rat es an enhanc ing mass at t he resec t ion sit e near t he pelv ic f loor (ar r ow s). B: Sagit t al T 2- w eight ed half F ourier t urbo spin- ec ho (HAST E) (90/4.5) magnet ic resonanc e image show s a high signal f ist ula bet w een t he bladder and t umor mass (ar r ow )

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3026

20 - Pelvis

F igure 20- 46 Ent erov aginal absc ess and f ist ula f ollow ing a hy st erec t omy . Axial c omput ed t omography images of t he pelv is obt ained f ollow ing t he ingest ion of oral c ont rast demonst rat e an abnormal c ollec t ion of gas and c ont rast mat erial int erposed bet w een a small bow el loop and t he v agina (ar r ow , A). High- densit y c ont rast is present w it hin t he v aginal c anal c onf irming t he presenc e of a f ist ula (ar r ow heads, B). C : c oronal ref ormat t ed maximum int ensit y projec t ion 5 mm in t hic kness again show s t he absc ess (ar r ow ) and it s relat ion t o t he lef t v aginal f ornix.

P.1413

REFERENCES 1. Asc her SM, Arnold LL, Pat t RH, et al. Adenomy osis: prospec t iv e c omparison of MR imaging and t ransv aginal sonography . Radiology 1994;190:803–806. 2. Asc her SM, Imaoka I, Lage JM. T amoxif en- induc ed ut erine abnormalit ies: t he role of imaging. Radiology 2000;214:29–38. 3. Asc her SM, Johnson JC, Barnes WA, et al. MR imaging appearanc e of t he ut erus in post menopausal w omen rec eiv ing t amoxif en t herapy f or breast c anc er: hist opat hologic c orrelat ion. Radiology 1996;200:105–110. 4. Azziz R. Adenomy osis: c urrent perspec t iv es. Obst et Gy nec ol Clin Nor t h Am 1989;16:221–235.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3027

20 - Pelvis

5. Barent sz JO, Berger- Hart og O, Wit jes JA, et al. Ev aluat ion of c hemot herapy in adv anc ed urinary bladder c anc er w it h f ast dy namic c ont rast - enhanc ed MR imaging. Radiology 1998;207: 791–797. 6. Barent sz JO, Jager GJ, v an Vierzen Pet er BJ, et al. St aging urinary bladder c anc er af t er t ransuret hral biopsy : v alue of f ast dy namic c ont rast - enhanc ed MR imaging. Radiology 1996;201: 185–193. 7. Bart on JW, Mc Cart hy SM, Kohorn EI, et al. Pelv ic MR imaging f indings in gest at ional t rophoblast ic disease, inc omplet e abort ion, and ec t opic pregnanc y : are t hey spec if ic ? Radiology 1993;186: 163–168. 8. Blomlie V, Rof st ad EK, T ropé C, et al. Crit ic al sof t t issues of t he f emale pelv is: serial MR imaging bef ore, during, and af t er radiat ion t herapy . Radiology 1997;203:391–397. 9. Blomlie V, Rof st ad EK, T v erå K, et al. Nonc rit ic al sof t t issues of t he f emale pelv is: serial MR imaging bef ore, during, and af t er radiat ion t herapy . Radiology 1996;199:461–468. 10. Boronow RC, Morrow CP, Creasman WT , et al. Surgic al st aging in endomet rial c anc er: c linic al- pat hologic f inding of a prospec t iv e st udy . Obst et Gy nec ol 1984;63:852–832. 11. Bree RL, Carlos RC. US f or post menopausal bleeding: c onsensus dev elopment and pat ient - c ent ered out c omes. Radiology 2002; 222:595–598. 12. Brody JM, Koelliker SL, F rishman GN. Unic ornuat e ut erus: imaging appearanc e, assoc iat ed anomalies, and c linic al implic at ions. AJR Am J Roent genol 1998;171:1341–1347. 13. But t ram VC. Müllerian anomalies and t heir management . F er t il St er il 1983;40:159–163. 14. Buy JN, Moss AA, Guinet C, et al. MR st aging of bladder c arc inoma: c orrelat ion w it h pat hologic f indings. Radiology 1988;169:695–700. 15. Caoili EM, Cohan RH, Korobkin M, et al. Urinary t rac t abnormalit ies: init ial experienc e w it h mult i- det ec t or row CT urography . Radiology 2002;222:353–360. 16. Cobby M, Brow ning J, Jones A, et al. Magnet ic resonanc e imaging, c omput ed t omography and endosonography in t he loc al st aging of c arc inoma of t he c erv ix. Br J Radiol 1990;63:673–679. 17. Cornud F , F lam T , Chauv einc L, et al. Ext raprost at ic spread of c linic ally loc alized prost at e c anc er: f ac t ors predic t iv e of pT 3 t umor and of posit iv e endorec t al MR imaging examinat ion result s. Radiology 2002;224:203–210.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3028

20 - Pelvis 18. Creasman WT . Disorders of t he ut erine c orpus. In: Sout t JR, DiSaia PH, Hammand CCB, Spellac y WN, eds. Dansf or t h's obst et r ic s and gy nec ology . Philadelphia: Lippinc ot t ; 1994:925–955. 19. Creasman WT , DeGeest K, DiSaia PJ, et al. Signif ic anc e of t rue surgic al

pat hologic st aging: a Gy nec ologic Onc ology Group St udy . Am J Obst et Gy nec ol 1999;181:31–34. 20. deSouza NM, Williams AD. Ut erine art erial embolizat ion f or leiomy omas: perf usion and v olume c hanges at MR imaging and relat ion t o c linic al out c ome. Radiology 2002;222:367–374. 21. Doy le M. Magnet ic resonanc e imaging in müllerian f usion def ec t s. J Repr od Med 1992;37:33–38. 22. Dudiak CM, T urner DA, Pat el SK, et al. Ut erine leiomy omas in t he inf ert ile pat ient : preoperat iv e loc alizat ion w it h MR imaging v ersus US and hy st erosalpingography . Radiology 1988;167:627–630. P.1414 23. F eong Y Y , Kang HK, Chung T W, et al. Ut erine c erv ic al c arc inoma af t er t herapy : CT and MR imaging f indings. Radiogr aphic s 2003;23:969–981. 24. F ielding JR. Prac t ic al MR imaging of f emale pelv ic f loor w eakness. Radiogr aphic s 2002;22:295–304. 25. F ielding JR, Hoy t e LX, Okon SA, et al. T umor det ec t ion by v irt ual c y st osc opy w it h c olor mapping of bladder w all t hic kness. J Ur ol 2002;167[2 Pt 1]:559–562. 26. F orman HP, Heiken JP, Brink JA, et al. CT sc reening f or c omorbid disease in pat ient s w it h prost at ic c arc inoma: is it c ost - ef f ec t iv e. AJR Am J Roent genol 1994;162:1125–1128; disc ussion 1129–1130. 27. F orst ner R, Hric ak H, Oc c hipint i KA, et al. Ov arian c anc er: st aging w it h CT and MR imaging. Radiology 1995;197:619–626. 28. F rei KA, Kinkel K, Bonél HM, et al. Predic t ion of deep my omet rial inv asion in pat ient s w it h endomet rial c anc er: c linic al ut ilit y of c ont rast - enhanc ed MR imaging—a met a- analy sis and bay esian analy sis. Radiology 2000;216:444–449. 29. F riedland GW, Chang P. T he role of imaging in t he management of t he impalpable undesc ended t est is. AJR Am J Roent genol 1988;151:1107–1111. 30. Ghossain MA, Buy JN, Ligneres C, et al. Epit helial t umors of t he ov ary : c omparison of MR and CT f indings. Radiology 1991;181: 863–870. 31. Golan A, Langer R, Bukov sky I, et al. Congenit al anomalies of t he müllerian sy st em. F er t il St er il 1989;51:747–755.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3029

20 - Pelvis 32. Greene F L, F leming ID, Page DL, et al., eds. AJCC Canc er St aging Handbook, 6t h ed. New Y ork: Springer- Verlag, 2002.

33. Gry speerdt S, Van Hoe L, Bosmans H, et al. T 2- w eight ed MR imaging of t he ut erus: c omparison of opt imized f ast spin- ec ho and HAST E sequenc es w it h c onv ent ional f ast spin- ec ho sequenc es. AJR Am J Roent genol 1998;171:211–215. 34. Hamlin DJ, F it zsimmons JR, Pet t ersson H, et al. Magnet ic resonanc e imaging of t he pelv is: ev aluat ion of ov arian masses at 0.15T . AJR Am J Roent genol 1985;145:585–590. 35. Hammer- Jac obsen E. T herapeut ic abort ion on ac c ount of x- ray examinat ion during pregnanc y . Dan Med Bull 1959;6:113–121. 36. Hardest y LA, Sumkin JH, Hankim C, et al. T he abilit y of helic al CT t o preoperat iv ely st age endomet rial c arc inoma. AJR Am J Roent genol 2001;176:603–606. 37. Hardest y LA, Sumkin JH, Nat h ME, et al. Use of preoperat iv e MR imaging in t he management of endomet rial c arc inoma: c ost analy sis. Radiology 2000;215:45–49. 38. Harisinghani MG, Barent sz JO, Hahn PF , et al. MR ly mphangiography f or det ec t ion of minimal nodal disease in pat ient s w it h prost at e c anc er. Ac ad Radiol 2002;9[Suppl 2]:S312–313. 39. Harisinghani MG, Barent sz J, Hahn PF , et al. Noninv asiv e det ec t ion of c linic ally oc c ult ly mph- node met ast ases in prost at e c anc er. N Engl J Med 2003;348:2491–2499. 40. Harris RD, Sc hned AR, Heaney JA. St aging of prost at e c anc er w it h endorec t al MR imaging: lessons f rom a learning c urv e. Radiogr aphic s 1995;15:813–829. 41. Haw ighorst Hans, Knapst ein PG, Weikel W, et al. Cerv ic al c arc inoma: c omparison of st andard and pharmac okinet ic MR imaging. Radiology 1996;201:531–539. 42. Hay ashi N, T oc higi H, Shiraishi T , et al. A new st aging c rit erion f or bladder c arc inoma using gadolinium- enhanc ed magnet ic resonanc e imaging w it h an endorec t al surf ac e c oil: a c omparison w it h ult rasonography . BJU Int 2000;85:32–36. 43. Healy JC, Phillips RR, Reznek RH, et al. T he MR appearanc e of v aginal f ist ulas. AJR Am J Roent genol 1996;167:1487–1489. 44. Hilt on S, Herr HW, T eit c her JB, et al. CT det ec t ion of ret roperit oneal ly mph node met ast ases I pat ient s w it h c linic al st age I t est ic ular

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3030

20 - Pelvis nonseminomat ous germ c ell c anc er: assessment of size and dist ribut ion c rit eria. AJR Am J Roent genol 1997;169:521–525.

45. Hoy t e L, Sc hierlit z L, Zou K, et al. T w o- and 3- dimensional MRI c omparison of lev at or ani st ruc t ure, v olume, and int egrit y in w omen w it h st ress inc ont inenc e and prolapse. Am J Obst et Gy nec ol 2001;185:11–19. 46. Iy er RB, Jhingran A, Saw af H, et al. Imaging f indings af t er radiot herapy t o t he pelv is. AJR Am J Roent genol 2001;177:1083–1089. 47. Jha RC, T akahma J, Imaoka I, et al. Adenomy osis: MRI of t he ut erus t reat ed w it h ut erine art ery embolizat ion. AJR Am J Roent genol 2003;181:851–856. 48. Jemal A, Murray T , Samuels A, et al. Canc er st at ist ic s, 2003. CA Canc er J Clin 2003;53:5–26. 49. Kanal E, Borgst ede JP, Barkov ic h AJ, et al. Americ an College of Radiology Whit e Paper on MR saf et y . AJR Am J Roent genol 2002;178:1335–1347. 50. Kang S, T urner DA, F ost er GS, et al. Adenomy osis: spec if ic it y of 5 mm as t he maximum normal ut erine junc t ional zone t hic kness in MR images. AJR Am J Roent genol 1996;166:1145–1150. 51. Kauf man RH, Noller K, Adam E, et al. Upper genit al t rac t abnormalit ies and pregnanc y out c ome in diet hy lst ilbest rol- exposed progeny . Am J Obst et Gy nec ol 1984;148:973–984. 52. Kier R, Mc Cart hy SM, Sc out t LM, et al. Pelv ic masses in pregnanc y : MR imaging. Radiology 1990;176:709–713. 53. Kim SH, Choi BI, Lee HP, et al. Ut erine c erv ic al c arc inoma: c omparison of CT and MR f indings. Radiology 1990;175:45–51. 54. Kimura I, T ogashi K, Kaw akami S, et al. Poly c y st ic ov aries: implic at ions of diagnosis w it h MR imaging. Radiology 1996;201:549–552. 55. Kinkel K, Aric he M, T ardiv on AA, et al. Dif f erent iat ion bet w een rec urrent t umor and benign c ondit ions af t er t reat ment of gy nec ologic pelv ic c arc inoma: v alue of dy namic c ont rast - enhanc e subt rac t ion MR imaging. Radiology 1997;204:55–63. 56. Kinkel K, Kaji Y , Y u KK, et al. Radiologic st aging in pat ient s w it h endomet rial c anc er: a met a- analy sis. Radiology 1999;212:711–718. 57. Kinkel K, T ardiv on AA, Soy er P, et al. Dy namic c ont rast - enhanc ed subt rac t ion v ersus T 2- w eight ed spin- ec ho MR imaging in t he f ollow - up of c olorec t al neoplasm: a prospec t iv e st udy of 41 pat ient s. Radiology 1996;200:453–458.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3031

20 - Pelvis

58. Kurhanew ic z J, Vigneron DB, Males RG, et al. T he prost at e: MR imaging and spec t rosc opy . Radiol Clin Nor t h Am 2000;38:115–138. 59. Kurt z AB, T simikas JV, T empany CMC, et al. Diagnosis and st aging of ov arian c anc er: c omparat iv e v alues of Doppler and c onv ent ional US, CT , and MR imaging c orrelat ed w it h surgery and hist opat hologic analy sis—report of t he Radiology Diagnost ic Onc ology Group. Radiology 1999;212:19–27. 60. Lev ine D, Barnes PD, Edelman RR. Obst et ric MR imaging. Radiology 1999;211:609–617. 61. Low RN, Saleh F , Song SY T , et al. T reat ed ov arian c anc er: c omparison of MR imaging w it h serum CA- 125 lev el and phy sic al examinat ion—a longit udinal st udy . Radiology 1999;211:519–528. 62. Mit c hell DG, Mint a MC, Sprit zer CE, et al. Adnexal masses: MR imaging observ at ions at 1.5T , w it h US and CT c orrelat ion. Radiology 1987;162:319–324. 63. Mey er JI, Kennedy AW, F riedman R, et al. Ov arian c arc inoma: v alue of CT in predic t ing suc c ess of debulking surgery . AJR Am J Roent genol 1995;165:875–878. 64. Morrow CP, Bundy BN, Kurman RJ, et al. Relat ionship bet w een surgic alpat hologic al risk f ac t ors and out c ome in c linic al st age I and II c arc inoma of t he endomet rium Gy nec ologic Onc ology Group st udy . Gy nec ol Onc ol 1991;40:55–65. 65. Most af a A, Reinhold C, Mehio AR, et al. Adenomy osis: US f eat ures w it h hist ologic c orrelat ion in an in v it ro st udy . Radiology 2000;215:783–790. 66. Murase E, Siegelman ES, Out w at er EK, et al. Ut erine leiomy omas: hist opat hologic f eat ures, MR imaging f indings, dif f erent ial diagnosis, and t reat ment . Radiogr aphic s 1999;19:1179–1197. 67. Nagay ama M, Wat anabe Y , Okumura A, et al. F ast MR imaging in obst et ric s. Radiogr aphic s 2002;22:563–582. 68. Oc c hipint i KA, F rankel SD, Hric ak H. T he ov ary : c omput ed t omography and magnet ic resonanc e imaging. Radiol Clin Nor t h Am 1993;31:1115–1132. 69. Out w at er EK, Mit c hell DG. Normal ov aries and f unc t ional c y st s: MR appearanc e. Radiology 1996;198:397–402. 70. Out w at er E, Sc hiebler ML, Ow en RS, et al. Charac t erizat ion of hemorrhagic adnexal lesions w it h MR imaging: blinded reader st udy . Radiology 1993;186:489–494. 71. Out w at er EK, Siegelman ES, Chiow anic h P, et al. Dilat ed f allopian t ubes: MR imaging c harac t erist ic s. Radiology 1998;208:463–469.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3032

20 - Pelvis

72. Out w at er EK, Siegelman ES, Van Deerlin V. Adenomy osis: c urrent c onc ept s and imaging c onsiderat ions. AJR Am J Roent genol 1998;170:437–441. 73. Out w at er EK, T alerman A, Dunt on C. Normal adnexa ut eri spec imens: anat omic basis of MR imaging f eat ures. Radiology 1996;201:751–755. P.1415 74. Pellerit o JS, Mc Cart h SM, Doy le MB, et al. Diagnosis of ut erine anomalies: relat iv e ac c urac y of MR imaging, endov aginal sonography , and hy st erosalpingography . Radiology 1992;183:795–800. 75. Reinhold C, At ri M, Mehio A, et al. Dif f use ut erine adenomy osis: morphologic c rit eria and diagnost ic ac c urac y of endov aginal sonography . Radiology 1995;197:609–614. 76. Reinhold C, Hric ak H, F orst ner R, et al. Primary amenorrhea: ev aluat ion w it h MR imaging. Radiology 1997;203:383–390. 77. Reinhold C, Mc Cart hy S, Bret PM, et al. Dif f use adenomy osis: c omparison of endov aginal US and MR imaging w it h hist opat hologic c orrelat ion. Radiology 1996;199:151–158. 78. Rha SE, By un F Y , Seung EJ, et al. CT and MR imaging f eat ures of adnexal t orsion. Radiogr aphic s 2002;22:283–294. 79. Rubin SC. Cerv ic al c anc er: suc c esses and f ailures. CA Canc er J Clin 2001;51:92–114. 80. Saez F , Urresola A, Larena JA, et al. Endomet rial c arc inoma: assessment of my omet rial inv asion w it h plain and gadolinium- enhanc ed MR imaging. J Magn Reson Im aging 2000;12:460–466. 81. Sc heidler J, Heuc k AF . Imaging of c anc er of t he c erv ix. Radiol Clin Nor t h Am 2002;40:577–590. 82. Sc hw art z LH, LaT rent a LR, Bonac c io E, et al. Small c ell and anaplast ic prost at e c anc er: c orrelat ion bet w een CT f indings and prost at e- spec if ic ant igen lev el. Radiology 1998;208:735–738. 83. Sc out t LM, F ly nn SD, Lut hringer DJ, et al. Junc t ional zone of t he ut erus: c orrelat ion of MR imaging and hist ologic examinat ion of hy st erec t omy spec imens. Radiology 1991;179:403–407. 84. Sc out t LM, Mc Cauley T R, F ly nn SD, et al. Zonal Anat omy of t he c erv ix: c orrelat ion of MR imaging and hist ologic examinat ion of hy st erec t omy spec imens. Radiology 1993;186:159–162. 85. Seki H, T akano T , Sakai K. Value of dy namic MR imaging in assessing endomet rial c arc inoma inv olv ement of t he c erv ix. AJR Am J Roent genol 2000;175:171–176.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3033

20 - Pelvis 86. Siegelman ES, Out w at er EK, Banner MP, et al. High- resolut ion MR imaging of t he v agina. Radiogr aphic s 1997;17:1183–1203. 87. Silv erman JM, Krebs T L. MR imaging ev aluat ion w it h a t ransrec t al surf ac e

c oil of loc al rec urrenc e of prost at ic c anc er in men w ho hav e undergone radic al prost at ec t omy . AJR Am J Roent genol 1997;168:379–385. 88. Slanet z PJ, Hahn PF , Hall DA, et al. T he f requenc y and signif ic anc e of adnexal lesions inc ident ally rev ealed by CT . AJR Am J Roent genol 1997;168:647–650. 89. Song JH, F ranc is IR, Plat t JF , et al. Bladder t umor det ec t ion at v irt ual c y st osc opy . Radiology 2001;218:95–100. 90. S[c irc led div ision slash]rensen SS. Est imat ed prev alenc e of müllerian anomalies. Ac t a Obst et Gy nec ol Sc and 1988;67:441–445. 91. St ev ens SK, Hric ak H, Campos Z. T erat omas v ersus c y st ic hemorrhagic adnexal lesions: dif f erent iat ion w it h prot on- selec t iv e f at - sat urat ion MR imaging. Radiology 1993;186:481–488. 92. St rübbe EH, Willemsen WNP, Lemmens JAM, et al. May er- Rokit ansky Küst er- Hauser sy ndrome: dist inc t ion bet w een t w o f orms based on exc ret ory urographic , sonographic , and laparosc opic f indings. AJR Am J Roent genol 1993;160:331–334. 93. T empany CM, Zhou X, Zerhouni EA, et al. St aging of prost at e c anc er: result s of Radiology Diagnost ic Onc ology Group projec t c omparison of t hree MR imaging t ec hniques. Radiology 1994;192: 47–54. 94. T ogashi K, Nakai A, Sugimura K. Anat omy and phy siology of t he f emale pelv is: MR imaging rev isit ed. J Magn Reson Im aging 2001;13:842–849. 95. T ogashi K, Nishimura K, It oh K, et al. Ov arian c y st ic t erat omas: MR imaging. Radiology 1987;162:669–673. 96. T ukev a T A, Aronen HJ, Karjalainen PT , et al. MR imaging in pelv ic inf lammat ory disease: c omparison w it h laparosc opy and US. Radiology 1999;210:209–216. 97. T w ic kler DM, Set iaw an AT , Ev ans RS, et al. Imaging of puerperal sept ic t hrombophlebit is: prospec t iv e c omparison of MR imaging, CT , and sonography . AJR Am J Roent genol 1997;169:1039–1043. 98. Van Gils APG, T ham RT OT A, F alke T HM, et al. Abnormalit ies and pregnanc y out c ome in diet hy lst ilbest rol exposure: c orrelat ion of f indings on MR and hy st erosalpingography . AJR Am J Roent genol 1989;153:1235–1238.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3034

20 - Pelvis 99. Walsh JW, Rosenf ield AT , Jaf f e CC, et al. Prospec t iv e c omparison of ult rasound and c omput ed t omography in t he ev aluat ion of gy nec ologic pelv ic masses. AJR Am J Roent genol 1978;131: 955–960. 100. Weinreb JC, Barkof f ND, Megibow A, et al. T he v alue of MR imaging in dist inguishing leiomy omas f rom ot her solid pelv ic masses w hen sonography is indet erminat e. AJR Am J Roent genol 1990;154:295–299.

101. Williams AD, Cousins C, Sout t er WP, et al. Det ec t ion of pelv ic ly mph node met ast ases in gy nec ologic malignanc y : a c omparison of CT , MR imaging, and posit ron emission t omography . AJR Am J Roent genol 2001;177:343–348. 102. Woodw ard PJ, Wagner BJ, F arley T E. MR imaging in t he ev aluat ion of f emale inf ert ilit y . Radiogr aphic s 1993;13:293–310. 103. Y amashit a Y , Harada M, Saw ada T , et al. Normal ut erus and F IGO st age I endomet rial c arc inoma: dy namic gadolinium- enhanc ed MR imaging. Radiology 1993;186:495–501. 104. Y amashit a Y , T orashima M, Hat anaka Y , et al. Adnexal masses: ac c urac y of c harac t erizat ion w it h t ransv aginal US and prec ont rast and post c ont rast MR imaging. Radiology 1995;194:557–565. 105. Y amashit a Y , T orashima M, T akahashi M, et al. Hy perint ense ut erine leiomy oma at T 2- w eight ed MR imaging: dif f erent iat ion w it h dy namic enhanc ed MR imaging and c linic al implic at ions. Radiology 1993;189:721–725. 106. Y ang WT , Lam WWM, Y u MY , et al. Comparison of dy namic helic al CT and dy namic MR imaging in t he ev aluat ion of pelv ic ly mph nodes in c erv ic al c arc inoma. AJR Am J Roent genol 2000; 175:759–766. 107. Y u KK, Hric ak H, Alagappan R, et al. Det ec t ion of ext rac apsular ext ension of prost at e c arc inoma w it h endorec t al and phased- array c oil MR imaging: mult iv ariat e f eat ure analy sis. Radiology 1997;202:697–702. 108. Y u KK, Hric ak H, Subak LL, et al. Preoperat iv e st aging of c erv ic al c arc inoma: phased array c oil f ast spin- ec ho v ersus body c oil spin- ec ho T 2w eight ed MR imaging. AJR Am J Roent genol 1998; 171:707–711. 109. Zaw in M, Mc Cart hy S, Sc out t LM, et al. High- f ield MRI and US ev aluat ion of t he pelv is in w omen w it h leiomy omas. J Magn Reson Im aging 1990;8:371–376.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma

21 - Computed Tomography of Thoracoabdominal Trauma3036 26

21 - Computed Tomography of Thoracoabdominal Trauma Editors: Le e , Jose ph K. T. ; Sa ge l, Stua rt S. ; Sta nle y , Robe rt J. ; He ike n, Ja y P. Title : C ompute d Body Tomogra phy with MRI C orre la tion , 4th Edition Copy right В©2006 Lippinc ot t Williams & Wilkins > T able of Cont ent s > 21 - Comput ed T omography of T horac oabdominal T rauma

21 Computed Tomography of Thoracoabdominal Trauma Pa ul L. Molina Mic he le T. Quinn Edwa rd W. Bouc ha rd Jose ph K. T. Le e T rauma is t he f if t h leading c ause of deat h in t he Unit ed St at es (1), and it is t he leading c ause of deat h in persons under t he age of 40 y ears (319). Pot ent ial lif e y ears lost as a result of t rauma exc eed t hose result ing f rom heart disease and c anc er (424). T rauma also result s in more t han 100,000 permanent disabilit ies annually (158). Blunt t rauma, also c alled w ide impac t t rauma, ac c ount s f or t he majorit y of injuries and is most c ommonly t he result of mot or v ehic le ac c ident s. Ot her f requent c auses inc lude home and w ork- relat ed ac c ident s suc h as c rush injuries, blast injuries, and f alls f rom a height . Mult isy st em t rauma is a c harac t erist ic of mot or v ehic le ac c ident s, w it h t he ext remit ies inv olv ed most f requent ly , f ollow ed by injury t o t he head (70%), c hest (50%), abdomen (30%), and pelv is (25%) (424). Improv ed t riage using t elec ommunic at ion and expedit ed t ransport t o designat ed t rauma c ent ers has enhanc ed surv iv al of major t rauma v ic t ims (16). T rauma c ent ers ef f ec t iv ely reduc e morbidit y and mort alit y of t he ac c ident pat ient , and t he nat ionw ide dev elopment of t he Emergenc y Medic al Serv ic e Sy st em, w hic h ident if ies t rauma c ent ers by a proc ess of c at egorizat ion, regionalizat ion, and v erif ic at ion, has markedly improv ed t he c are of t rauma pat ient s (271). Anot her signif ic ant adv anc ement in modern t rauma c are has been t he int ensiv e use of c omput ed t omography (CT ) f or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3037 immediat e pat ient ev aluat ion. Ov er t he last sev eral dec ades, improv ement s in CT sc anner hardw are and sof t w are hav e prov ided inc reased sc anning speed and f ast er dat a ac quisit ion, as w ell as improv ed spat ial resolut ion (319). T he c ont inuing ev olut ion in CT t ec hnology f rom c onv ent ional t o helic al sc anning, and t hen f rom single- det ec t or CT (SDCT ) t o mult idet ec t or CT (MDCT ) has led t o unprec edent ed speed and qualit y of CT imaging. As a c onsequenc e, CT has solidif ied it s role as t he primary diagnost ic t ool in t he ev aluat ion of t he hemody namic ally st able blunt t rauma v ic t im. T he new est generat ion of MDCT sc anners prov ides sev eral adv ant ages f or t he t rauma pat ient . T he f ast sc anning t ime of MDCT makes larger pat ient c ov erage possible in a single breat h- hold w it h t hinner slic es and great er spat ial resolut ion, allow ing f or t he rapid perf ormanc e of sev eral, sequent ial examinat ions in a pat ient w it h injuries t o mult iple body part s (466). Mot ion art if ac t s are signif ic ant ly reduc ed w it h MDCT and c ont rast bolus imaging is improv ed, leading t o bet t er int rav enous (IV) c ont rast mat erial opac if ic at ion of blood v essels and improv ed IV c ont rast mat erial enhanc ement of solid organs (319). Addit ionally , high- qualit y mult iplanar ref ormat ions and t hree- dimensional (3D) rec onst ruc t ions w it h preserv at ion of spat ial resolut ion are made possible by t he near- isot ropic imaging prov ided by t he t hinner c ollimat ion used w it h MDCT (436). P.1418

BLUNT THORACIC TRAUMA Blunt c hest t rauma is muc h more c ommon t han penet rat ing c hest t rauma and is responsible f or almost 90% of t he c hest injuries t hat oc c ur in c iv ilian populat ions (160). Chest injury , alone or in c ombinat ion w it h ot her injuries, ac c ount s f or nearly half of all t raumat ic deat hs. T he ov erall deat h rat e is 2% t o 12% f or isolat ed c hest injuries. F or pat ient s w it h c hest injuries assoc iat ed w it h poly t rauma, t he mort alit y rat e rises t o 35% (158). Most pat ient s w it h blunt c hest t rauma hav e assoc iat ed ext rat horac ic injuries. In a represent at iv e large series of 515 c ases of blunt c hest t rauma, 431 pat ient s (84%) had ext rat horac ic injuries, and nearly half of t hese pat ient s had inv olv ement of t w o or more ext rat horac ic sit es (401). T he most c ommon assoc iat ed injuries w ere head t rauma, ext remit y f rac t ures, and int raabdominal injuries. T hese ext rat horac ic injuries in c onjunc t ion w it h t horac ic t rauma c an lead t o addit ional impairment of respirat ory f unc t ion. Head injuries, f or example, c an result in aspirat ion or neurogenic pulmonary edema. Skelet al t rauma c ombined

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3038 w it h hy pov olemic shoc k c an produc e t he f at embolism sy ndrome. Abdominal injuries result ing in hemorrhagic shoc k (i.e., hepat ic or splenic lac erat ions) may also c ompound t he ef f ec t s of blunt c hest t rauma (425). Blunt c hest injury result s f rom t he t ransf er of kinet ic energy t o t he c hest w all and t horac ic c ont ent s t hrough a number of sy nergist ic mec hanisms inc luding (a) direc t impac t , (b) sudden inert ial dec elerat ion, (c ) spallat ion, and (d) implosion. Dir ec t im pac t , as oc c urs w it h f orc ef ul, direc t blow s t o t he c hest , c auses a sudden release of loc al kinet ic energy t hat may f rac t ure bony st ruc t ures and c ont use, c rush, and shear underly ing sof t t issues. If t he c hest w all is c ompressed subst ant ially by t he f orc e of t he impac t , t he result ant inc rease in int rat horac ic pressure may also lead t o rupt ure of alv eoli and support ing st ruc t ures. Sudden iner t ial dec eler at ion at t he t ime of impac t is a major injury f ac t or in high- speed mot or v ehic le ac c ident s. Inert ial dec elerat ion impart s dif f erent ial moment s of rot at ion t o c hest t issues and c auses mobile or elast ic st ruc t ures t o rot at e about point s of f ixat ion. T he result ing t orsional def ormat ion and shearing st resses at int ernal t horac ic int erf ac es (i.e., int erf ac e bet w een t he relat iv ely mobile alv eolar t issues and t he more f ixed bronc hov asc ular int erst it ium) c an c ause mic rosc opic t ears or gross lac erat ions. Spallat ion oc c urs w hen a broad kinet ic shoc k w av e f rom sudden c ompression is part ially ref lec t ed at gas- f luid int erf ac es, suc h as at t he alv eoloc apillary surf ac e. T he result ing release of energy c auses loc al disrupt ion of t issue near t he point of shoc k- w av e impac t . Spallat ion injury is t y pic ally manif est in t he ant erior lung during sudden c ompression of t he ant erior c hest w all in st eering w heel injuries. Im plosion is t he low - pressure dec ompressiv e w av e t hat f ollow s t he high- pressure c ompressiv e shoc k w av e of spallat ion, c ausing disrupt ion of lung t issue t hrough rebound ov erexpansion of gas bubbles w it hin alv eoli. In most c ases, blunt t horac ic injury is t he result of a c ombinat ion of t hese major energy t ransf er mec hanisms (144,158).

INDICATIONS Alt hough CT is t he examinat ion of c hoic e in t rauma of t he head and abdomen, it s prec ise role in t he ev aluat ion of blunt c hest t rauma c ont inues t o ev olv e. T his is largely bec ause of t he remarkable amount of inf ormat ion prov ided by c hest radiography , w hic h remains t he princ ipal diagnost ic sc reening examinat ion in pat ient s w it h blunt t horac ic t rauma. Many t raumat ic abnormalit ies of t he t horax (e.g., t ension pneumot horax, hemot horax, pulmonary c ont usion) c an be diagnosed or suggest ed w it h reasonable

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3039 c onf idenc e by c onv ent ional radiographic met hods. In st able post t raumat ic pat ient s, t horac ic CT c an be perf ormed t o c onf irm or, more prec isely , def ine t he f ull ext ent of t horac ic injury , w hic h is of t en underest imat ed by c hest radiography (218,263,273,296,362,412,443,458). CT c an be part ic ularly benef ic ial in pat ient s w it h equiv oc al radiographic f indings or t ec hnic ally inadequat e radiographic examinat ions. CT may also be used t o diagnose radiographic ally inapparent or c linic ally unsuspec t ed injuries, suc h as parenc hy mal lac erat ions or oc c ult pneumot horac es. CT is f ast bec oming t he primary imaging modalit y f ollow ing c hest radiography f or ev aluat ion of pat ient s w it h suspec t ed t raumat ic aort ic injury . In t he lat er post injury st age, addit ional indic at ions f or use of CT inc lude demonst rat ion of sit es of t horac ic inf ec t ion (292), dif f erent iat ion of pleural f rom parenc hy mal abnormalit ies (154), and guidanc e of t herapeut ic int erv ent ions suc h as empy ema drainage (35) or rev ision of malposit ioned and oc c luded t horac ost omy t ubes (292). In general, magnet ic resonanc e imaging (MRI) is not used rout inely t o assess ac ut e c hest or abdominal t rauma, bec ause prolonged sc an t imes and dec reased ac c ess t o pat ient s requiring c ont inuous monit oring limit it s prac t ic alit y in t he imaging of t rauma pat ient s (492). Oc c asionally , in selec t hemody namic ally st able pat ient s, MRI may be of use in t he init ial ev aluat ion of suspec t ed injuries t o t he spine and diaphragm (151,396).

TECHNIQUE Post t raumat ic t horac ic SDCT examinat ions are generally perf ormed at 5- mm c ollimat ion, a pit c h of 1.0 t o 1.5, and 5- mm int erv als t hrough t he ent ire t horax f ollow ing t he bolus administ rat ion of IV c ont rast mat erial. T y pic ally , 90 t o 120 mL of nonionic c ont rast mat erial w it h an iodine c onc ent rat ion of 240 t o 300 mg/mL is administ ered using a pow er injec t or at 2 t o 4 mL per sec ond t hrough a 20- gauge or larger peripheral v enous c at het er. Injec t ion of t he right ant ec ubit al f ossa is pref erred t o t he lef t t o av oid c ont rast art if ac t f rom t he lef t brac hioc ephalic v ein, w hic h c an limit ev aluat ion of t he mediast inum (319). Sc anning is P.1419 init iat ed af t er a delay of 20 t o 25 sec onds during a single breat h- hold and images are rev iew ed at lung, sof t - t issue, and bone w indow set t ings. When mult iplanar or 3D ref ormat ions are indic at ed, images are rec onst ruc t ed at 1t o 3- mm spac ing. Cardiac - gat ing may f urt her improv e image qualit y by limit ing c ardiov asc ular mot ion art if ac t and improv ing rec onst ruc t ions (366).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3040 Paramet ers suc h as slic e c ollimat ion, pit c h, and rec onst ruc t ion int erv al may v ary depending on t he number of CT sc anner det ec t ors. F or t he 16- c hannel sc anners, t y pic al c ollimat ion c hoic es are 1.5 mm and 0.75 mm. Wit h t he 64c hannel sc anners, 1.2- t o 0.6- mm c ollimat ion is ac hiev able. Whenev er perf orming t rauma CT , t he pat ient should be c losely monit ored t hroughout t he examinat ion by t rained medic al personnel, and emergenc y resusc it at iv e equipment must be immediat ely av ailable in t he CT sc anning room. If possible, t he pat ient 's arms should be posit ioned abov e t he head rat her t han along t he sides so as t o reduc e st reak art if ac t s. Art if ac t s c an also be minimized by remov ing as many nonessent ial t ubes and ot her f oreign objec t s f rom t he sc anning f ield as possible prior t o imaging.

SPECIFIC TRAUMA SITES Chest Wall T rauma t o t he c hest of t en result s in injury t o t he bony t horax and sof t t issues of t he c hest w all, inc reasing pat ient morbidit y and mort alit y (64). F or t he majorit y of c hest w all injuries, a c ombinat ion of phy sic al examinat ion and radiographs is suf f ic ient t o def ine t heir nat ure and ext ent . Chest w all c ont usion, w it h or w it hout rib f rac t ure, c an produc e a ret ic ular pat t ern of higher densit y w it hin t he usually homogeneous subc ut aneous f at . Sof t t issue hemat omas c an oblit erat e f at - t issue planes bet w een musc les and produc e a f oc al mass- like bulge (242) (F ig. 21- 1). Bot h c ont usions and hemat omas of t he c hest w all are readily demonst rat ed by CT , but are generally of lit t le c linic al signif ic anc e. Subc ut aneous or int ramusc ular c hest w all emphy sema is also readily demonst rat ed by CT bec ause of t he signif ic ant c ont rast dif f erenc e bet w een air and sof t t issue. Subc ut aneous emphy sema appears on CT as bands of air w it hin t he subc ut aneous f at and along or bet w een t he c hest w all musc les. F ollow ing blunt c hest t rauma, t he f inding of subc ut aneous emphy sema c an indic at e t he presenc e of underly ing pneumot horax or pneumomediast inum, part ic ularly if skin lac erat ions or open sof t t issue w ounds are absent . Det ec t ion of mot t led subc ut aneous air and/or sof t t issue sw elling day s t o w eeks f ollow ing t rauma should suggest t he possibilit y of an absc ess, t he ext ent of w hic h c an be easily delineat ed w it h CT (154).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3041 Rib f rac t ures oc c ur in ov er 50% of pat ient s w it h signif ic ant c hest t rauma and most c ommonly af f ec t t he f ourt h t hrough nint h ribs (424). Alt hough rib f rac t ures are a c ommon sequela of blunt c hest t rauma, major int ernal t horac ic injury c an oc c ur in t he absenc e of rib f rac t ures or ot her ev ident injury t o t he c hest w all, part ic ularly in y ounger indiv iduals w it h c ompliant c hest w alls. T here is a muc h great er inc idenc e of rib f rac t ures in older adult s, w hose ribs are relat iv ely inelast ic , t han in c hildren, w hose ribs are generally more pliable and resilient (160). Rib f rac t ures, in and of t hemselv es, are usually of lit t le c linic al signif ic anc e and are not ac c urat e predic t ors of serious injury . How ev er, t hey do ref lec t t he magnit ude of f orc e impart ed and c an prov ide c lues as t o t he t y pe and loc at ion of underly ing injuries (158). F rac t ures of t he f irst t hree ribs indic at e signif ic ant energy t ransf er bec ause t hese ribs are prot ec t ed by t he shoulder girdles and by heav y surrounding musc ulat ure. T heir assoc iat ion w it h aort ic or t rac heobronc hial injury is not as c onst ant as prev iously believ ed, how ev er, and t hey are not , as isolat ed f indings, reliable predic t ors of aort ic rupt ure (126,239,484). Ext rapleural P.1420 hemat omas may ac c ompany f rac t ures of t he upper ribs or t rauma t o t he subc lav ian v essels ov er t he apex of t he lung. Suc h ext rapleural hemat omas or “ pleural c aps” c an mimic a large hemot horax on supine c hest radiographs. CT readily dist inguishes bet w een an ext rapleural c ollec t ion of blood ov er t he apex of t he lung and a hemot horax. F rac t ures of t he low er ribs, part ic ularly t he t ent h t hrough t w elf t h ribs, should inc rease suspic ion of hepat ic , splenic , or renal injury , as w ell as assoc iat ed int raperit oneal and ret roperit oneal hemorrhage. Conf irmat ion of suc h injuries should t hen be sought by appropriat e diagnost ic inv est igat ions, suc h as CT (242).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3042

F igure 21- 1 Chest w all hemat oma sec ondary t o lac erat ed t horac odorsal art ery f ollow ing blunt t rauma. Not e large lef t c hest w all hemat oma (H) and adjac ent displac ed rib f rac t ure (ar r ow ). Bilat eral low er lobe at elec t asis is also present .

F rac t ures of t hree or more sequent ial ribs or c ost al c art ilages in mult iple plac es c an lead t o an unst able, isolat ed segment of c hest w all t hat exhibit s paradoxic al respirat ory mot ion, t he so- c alled f lail c hest . T he f lail segment of c hest w all is suc ked in w it h inspirat ion and blow n out w it h expirat ion, mov ing in a direc t ion opposit e t o t he usual and leading t o impaired pulmonary v ent ilat ion. T he diagnosis of f lail c hest is made c linic ally and it represent s a v ery sev ere f orm of c hest w all injury . Bec ause signif ic ant f orc e is needed t o produc e a f lail segment , mult iple assoc iat ed injuries are f requent ly enc ount ered, many of w hic h c an be doc ument ed by CT if nec essary (e.g., lung c ont usion, lung lac erat ion, st ernal f rac t ure) (424). Rarely , a segment of lung may herniat e t hrough a def ec t in t he c hest w all c reat ed by t he f lail segment , and t his t oo c an be easily det ec t ed by CT (295). Addit ional f rac t ures of t he bony t horax disc ov ered by CT , inc luding sc apular (F ig. 21- 2), st ernal (F ig. 21- 3), or t horac ic spine f rac t ures (F ig. 21- 4), may be of c onsiderable v alue in c larif y ing radiographic f indings, eluc idat ing t he mec hanism of injury , and init iat ing inv est igat ion f or import ant assoc iat ed injuries. T horac ic spine f rac t ures most of t en inv olv e t he low er t horac ic spine (T - 9 t hrough T - 11 v ert ebrae) and are of part ic ular c linic al signif ic anc e bec ause t he t horac ic spinal c ord is unusually susc ept ible t o injury . In

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3043 c omparison w it h t he c erv ic al or lumbar spinal c ord, t he t horac ic spinal c ord oc c upies a great er perc ent age of t he t ot al c ross- sec t ional area of it s surrounding spinal c anal, and it is easily injured by displac ed f ragment s of bone or disk mat erial. T he blood supply t o t he midt horac ic spinal c ord is also v ery t enuous and, w hen disrupt ed, c an result in dev ast at ing neurologic def ic it s. CT c an ac c urat ely det ermine t he presenc e, ext ent , P.1421 and st abilit y of t horac ic spine f rac t ures. Vert ebral body f rac t ures are readily demonst rat ed on CT , as are t he relat ionships of f rac t ure f ragment s and displac ed disk mat erial t o t he spinal c ord (160).

F igure 21- 2 Sc apular f rac t ure. Comput ed t omography image t hrough t he upper c hest rev eals a sc apular f rac t ure (ar r ow ) not apprec iat ed on t he c hest radiograph. High- at t enuat ion int rav enous c ont rast mat erial is present in t he right axillary and brac hioc ephalic v eins f rom right arm injec t ion. et , endot rac heal t ube; c t , c hest t ube.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3044

F igure 21- 3 St ernal f rac t ure. Comput ed t omography image t hrough t he upper st ernum demonst rat es an oblique f rac t ure of t he st ernum (ar r ow heads). Assoc iat ed ret rost ernal and mediast inal hemat oma result ed in mediast inal w idening, S, superior v ena c av a; T , t rac hea.

F igure 21- 4 T horac ic spine f rac t ure. Comput ed t omography image t hrough t he low er c hest demonst rat es a burst f rac t ure of t he t horac ic v ert ebral body . Not e also t he large right pneumot horax (p) w it h right lung c ollapse (L).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3045 St ernal f rac t ures, oc c urring in 8% t o 10% of pat ient s af t er sev ere blunt t rauma, are more easily diagnosed on CT t han on supine c hest radiographs. CT is also superior f or det ec t ion of ret rost ernal hemat oma, w hic h may result f rom lac erat ion of t he int ernal mammary v essels by st ernal f rac t ure f ragment s. St ernal f rac t ures should elic it c onc ern about assoc iat ed my oc ardial injury , suc h as my oc ardial c ont usion, w hic h c an lead t o signif ic ant arrhy t hmias and hemody namic inst abilit y (424). Post erior disloc at ion of t he c lav ic le at t he st ernoc lav ic ular joint is anot her injury best v isualized by CT . Alt hough less c ommon t han ant erior disloc at ions, post erior disloc at ions of t he st ernoc lav ic ular joint are more dif f ic ult t o diagnose c linic ally and c an result in c ompression or lac erat ion of t he t rac hea, esophagus, and great v essels (247,426). Prompt reduc t ion of suc h disloc at ions c an dec rease t he likelihood of v isc eral injury (142).

Pleural Space Pneumothorax Pneumot horax, w it h or w it hout an assoc iat ed rib f rac t ure, is a f requent c omplic at ion of blunt c hest t rauma, oc c urring in up t o 40% of blunt t rauma v ic t ims (96). Pneumot horac es sec ondary t o t rauma are of t en bilat eral and assoc iat ed w it h hemot horax (158). When a rib f rac t ure is present w it h a pneumot horax (70% of c ases), lac erat ion of t he v isc eral pleura by rib f ragment s is usually t he c ause. When no f rac t ure is present (30% of c ases), t he mec hanism is likely t hat of parenc hy mal lung injury , inc luding lac erat ion, w it h subsequent int erst it ial emphy sema. Pneumomediast inum and subc ut aneous emphy sema may also dev elop (242,424). Addit ional c auses of post t raumat ic pneumot horax inc lude alv eolar c ompression in c rushing injuries, t rac heobronc hial or esophageal t ears, and barot rauma. T he supine c hest radiograph c an det ec t most pneumot horac es large enough t o require immediat e t horac ost omy . How ev er, it has been report ed t hat as many as 30% of pneumot horac es in c rit ic ally ill pat ient s are not det ec t ed on supine radiographs and t hat half of t hese progress t o t ension pneumot horac es (440). In t he supine posit ion, small amount s of pleural air t end t o c ollec t in t he ant eromedial and subpulmonic pleural spac es and may be dif f ic ult t o det ec t on supine c hest radiographs. T he use of lat eral dec ubit us radiography of t he uppermost lung w it h a horizont al beam, as w ell as c hest CT , has been rec ommended t o improv e det ec t ion of pneumot horac es.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3046 CT is an exquisit ely sensit iv e met hod f or det ec t ing a pneumot horax in t he supine posit ion. Oc c ult pneumot horax, def ined as pneumot horax ev ident by CT but not by c linic al examinat ion or c hest radiography , has been report ed in 2% t o 12% of pat ient s undergoing abdominal CT sc anning f or blunt t rauma (356,463,479) (F ig. 21- 5). A muc h higher perc ent age of oc c ult pneumot horax (44%) has been report ed in a selec t group of pat ient s w it h sev ere head t rauma undergoing limit ed c hest CT examinat ion in addit ion t o c ranial CT sc anning (441).

F igure 21- 5 Bilat eral oc c ult pneumot horac es. Comput ed t omography image t hrough t he low er c hest rev eals small, bilat eral pneumot horac es (p) t hat w ere not ident if ied on an ant eropost erior supine c hest radiograph.

Alt hough CT is c apable of demonst rat ing pneumot horac es t hat are not ev ident on c linic al examinat ion or plain radiographs, t he c linic al signif ic anc e of , and def init iv e indic at ions f or, CT det ec t ion of oc c ult pneumot horax are not ent irely c lear (32,180,313,480). As a general rule, a c aref ul searc h f or pneumot horac es in major t rauma pat ient s w it h seemingly normal supine c hest radiographs is appropriat e. In pat ient s already undergoing abdominal CT sc anning f or blunt t rauma, images of t he upper abdomen (low er t horax) should be v iew ed at lung w indow s in addit ion t o t he usual sof t t issue w indow s t o enhanc e det ec t ion of small pneumot horac es (463). Rec ognit ion of ev en a small, oc c ult pneumot horax is somet imes c rit ic al, part ic ularly in pat ient s requiring mec hanic al v ent ilat ion or general anest hesia f or emergent surgery . Barot rauma f rom mec hanic al v ent ilat ion and induc t ion of anest hesia may produc e enlargement of a pneumot horax result ing in signif ic ant

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3047 respirat ory or c ardiov asc ular c ompromise (101,195). Animal st udies hav e show n t hat inspirat ion of 75% nit rous oxide w ill double a 300- mL pneumot horax in 10 minut es and t riple it in 45 minut es (101). T o prev ent progression t o a t ension pneumot horax, prophy lac t ic t ube t horac ost omy is generally rec ommended f or oc c ult pneumot horac es in t rauma pat ient s needing t o undergo mec hanic al v ent ilat ion or general anest hesia (34,441). Pat ient s w it h a small, oc c ult pneumot horax w ho are hemody namic ally st able and not v ent ilat ed may be f ollow ed w it h c lose c linic al observ at ion and P.1422 serial c hest radiography t o det ec t an inc rease in size of t he pneumot horax. T ube t horac ost omy may t hen be perf ormed w hen appropriat e (34,65,136,180,313,479,480). In pat ient s t reat ed w it h a c hest t ube f or pneumot horax, CT may be helpf ul in assessing t he adequac y of c hest t ube plac ement and pneumot horax drainage. A large perc ent age of t horac ost omy t ubes plac ed f or ac ut e c hest t rauma lie w it hin a pleural f issure, but t hey may st ill f unc t ion as ef f ec t iv ely as t hose loc at ed elsew here in t he pleural spac e (77). At t imes, unsuspec t ed ext rapleural loc at ion of a c hest t ube and/or signif ic ant residual pneumot horax is det ec t ed on CT (141). In suc h sit uat ions, CT c an be used t o guide c hest t ube reposit ioning or addit ional c hest t ube insert ion. CT may also be of v alue in c harac t erizing a number of pot ent ially c onf using post t raumat ic air c ollec t ions not ed on c hest radiography . Medial pneumot horax, f or example, c an be dist inguished f rom pneumomediast inum, paramediast inal pneumat oc ele, or air w it hin t he pulmonary ligament on CT . A narrow air c ollec t ion w it h a f luid lev el oc c urring af t er blunt t rauma suggest s medial pneumot horax, w hereas a broad or spheric al gas c ollec t ion w it hout a f luid lev el suggest s post erior pneumomediast inum, part ic ularly w hen it oc c urs in assoc iat ion w it h respirat ory dist ress and mec hanic al v ent ilat ion (149). Underly ing pneumot horax in pat ient s w it h ext ensiv e subc ut aneous emphy sema c an also be reliably ident if ied w it h CT .

Pleural Effusion/Hemothorax Post t raumat ic pleural ef f usions may be c omposed of t ransudat e, exudat e, blood, or c hy le, or some mixt ure of t hese f luids. T ransudat iv e ef f usions c an oc c ur w it h ac ut e pulmonary at elec t asis or w it h v igorous resusc it at ion and ov erhy drat ion of t he pat ient (383). Exudat iv e ef f usions are of t en a result of inf ec t ion of t he pleural spac e. Chy lous pleural f luid may f ollow a c rush or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3048 penet rat ing injury t o t he t horax or nec k w it h result ant damage t o t he t horac ic duc t . T he ov erw helming majorit y of pleural ef f usions dev eloping af t er t rauma represent hemot horax (F ig. 21- 6). Hemot horax oc c urs in 50% of pat ient s w it h blunt t horac ic t rauma and is of t en bilat eral. It c an be c aused by many dif f erent injuries, suc h as lung c ont usion, lung lac erat ion, int erc ost al v essel lac erat ion, and mediast inal or diaphragmat ic t ears (158). When hemot horax is c aused by bleeding f rom t he lung (e.g., lung c ont usion), it is usually mild and self - limit ed. T he low perf usion pressures and ric h t hromboplast in c ont ent of t he lung f av or hemost asis, as does t he t amponade ef f ec t of assoc iat ed c ollapsed lung (30). A large, rapidly expanding hemot horax is more likely a result of injury t o higher- pressure art erial sourc es in t he c hest w all, diaphragm, or mediast inum. Lac erat ion of sy st emic v essels, suc h as t he int erc ost al art eries, int ernal mammary art eries, aort a, and great v essels, c an lead t o massiv e hemot horax and result ant shoc k. CT and sonography are more sensit iv e t han radiographs t o t he presenc e of pleural f luid c ollec t ions. In a st udy ev aluat ing t he f requenc y and signif ic anc e of t horac ic injuries det ec t ed on abdominal CT sc ans of mult iple t rauma pat ient s, hemot horax w as rec ognized by CT alone in 23 (88%) of 26 pat ient s (356). Alt hough most pleural f luid c ollec t ions apparent only at CT are small and may not require emergent drainage, possible inc reases in t heir size need t o be assessed, and t hey may require sampling t o det ermine t heir c ause. T he CT densit y of t he f luid c ollec t ion somet imes c an suggest it s origin. Ac ut e hemot horax, f or example, c an measure 70 t o 80 Hounsf ield unit s (HU), c ompared w it h 10 t o 20 HU f or most t ransudat es (443). Bec ause of t he t endenc y f or hemot horax t o produc e pleural f ibrosis, c hest t ube drainage is of t en indic at ed.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3049

F igure 21- 6 Hemot horax. Comput ed t omography image demonst rat es highat t enuat ion (50 Hounsf ield unit s) ef f usion (E) represent ing hemot horax. Not e nondisplac ed post erolat eral rib f rac t ure (ar r ow head).

Oc c asionally , ev en large pleural ef f usions, part ic ularly if sy mmet ric and bilat eral, may not be apparent on supine c hest radiographs. T he same is t rue of f luid c ollec t ions loc at ed at t he bases or t rapped behind st if f , nonc ompliant lung [suc h as dev elops w it h post t raumat ic ac ut e respirat ory dist ress sy ndrome (ARDS)]. Bot h CT and sonography c an readily ident if y suc h c ollec t ions as w ell as guide t heir aspirat ion and/or drainage (428). In pat ient s t reat ed w it h c at het er or t horac ost omy t ube drainage, CT may be part ic ularly benef ic ial in assessing t he adequac y of pleural drainage. Persist ent loc ulat ed c ollec t ions and/or malposit ioned c hest t ubes c an be reliably det ec t ed w it h CT (141) (F ig. 21- 7). When appropriat e, CT c an be used t o guide c hest t ube reposit ioning or addit ional c hest t ube insert ion (292,423). CT is also of v alue P.1423 in t he det ec t ion and drainage of assoc iat ed c omplic at ions suc h as empy ema (F ig. 21- 8) or lung absc ess. CT c an bet t er delineat e c omplex pleuroparenc hy mal opac it ies, dist inguishing pleural f luid f rom ot her c omponent s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3050 c ausing radiographic densit y suc h as at elec t asis, c onsolidat ion, or c ont usion (295).

F igure 21- 7 Malposit ioned c hest t ube. Comput ed t omography image t hrough t he low er c hest demonst rat es t hat t he right c hest t ube (st r aight ar r ow ) is w ell ant erior t o t he right pleural f luid c ollec t ion. Loc ules of air (c ur v ed ar r ow ) w it hin t he pleural f luid c ollec t ion w ere int roduc ed at t he t ime of c hest t ube plac ement .

Lung Parenchyma Pulmonary Contusion Pulmonary c ont usion is t he most c ommon injury result ing f rom blunt c hest t rauma (477), oc c urring in 30% t o 75% of pat ient s sust aining blunt t rauma t o t he c hest (225). P.1424 Cont usion result s in exudat ion of blood and/or edema f luid int o t he air spac es and int erst it ium of t he lung. Alt hough of t en mild and loc alized, pulmonary c ont usion may be w idespread and assoc iat ed w it h respirat ory f ailure. Massiv e c ont usion c an lead t o t he dev elopment of ARDS (63). T he mort alit y rat e f rom pulmonary c ont usion ranges f rom 14% t o 40%, depending on t he sev erit y and ext ent of lung damage and ot her injuries (158,225).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3051

F igure 21- 8 Oc c ult empy ema in a f ebrile pat ient f ollow ing blunt t rauma. A: Sc out v iew f rom t he c omput ed t omography (CT ) examinat ion is unremarkable exc ept f or hardw are relat ed t o a halo f ixat ion dev ic e t hat ov erlies t he upper c hest . B: CT image t hrough t he low er c hest rev eals an oc c ult empy ema (E).

Radiologic ally , pulmonary c ont usion generally result s in nonsegment al, air–spac e c onsolidat ion, w hic h may v ary f rom pat c hy , f aint , ill- def ined areas of inc reased parenc hy mal densit y t o ext ensiv e homogeneous opac if ic at ion in one or bot h lungs. Cont usions are f requent ly peripheral in dist ribut ion and t end t o oc c ur near t he sit e of blunt impac t and adjac ent t o solid st ruc t ures suc h as t he ribs, spine, heart , or liv er (354). Cont usions may also be seen in areas remot e f rom t he injured sit e bec ause of t he c ont rec oup ef f ec t (353,477). Usually , c ont usions appear w it hin f our t o six hours af t er injury and c lear w it hin t hree t o eight day s. T he abrupt onset and relat iv ely rapid c learing of areas of parenc hy mal opac if ic at ion are c harac t erist ic of pulmonary c ont usion. Cont usions may inc rease in size and bec ome more v isible f or up t o 48 hours af t er injury . Progressiv e inc rease in parenc hy mal opac if ic at ion af t er 48 hours or delay ed resolut ion bey ond six t o t en day s suggest s eit her t he w rong init ial diagnosis or superimposit ion of anot her pat hologic proc ess, suc h as pneumonia, at elec t asis, aspirat ion, or ARDS (242,295,425,430). Int ra- alv eolar blood and edema f luid w it hin c ont used lung, c oupled w it h impaired c learanc e of sec ret ions and regional diminished lung c omplianc e, prov ide a nidus f or t he dev elopment of inf ec t ion and sepsis. In addit ion, bec ause of disrupt ion of alv eolar/ c apillary membranes, c ont used lung is more susc ept ible t o pulmonary edema (175). Administ rat ion of large amount s of IV f luids may ac c ent uat e t he degree of edema and result in w orsening radiographic opac if ic at ion (158,175).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3052 T he ov erall sev erit y and ext ent of c ont usion are of t en underest imat ed at init ial c linic al and radiographic examinat ion (28). Rib f rac t ures or ot her ext ernal signs of c hest w all injury may be absent , ev en w hen ext ensiv e lif et hreat ening c ont usion has oc c urred. Animal st udies suggest t hat c ont usion inv olv ing up t o one t hird of t he lung may go undet ec t ed w it h plain radiography (103). CT is muc h more sensit iv e t han c hest radiography in det ermining t he presenc e and ext ent of pulmonary c ont usion (380,459,461). On CT , c ont usion appears as an ill- def ined area of hazy ground- glass densit y or c onsolidat ion, usually w it h a peripheral, nonsegment al dist ribut ion (F ig. 21- 9). As w it h c hest radiography , t he CT appearanc e of c ont usion init ially may be indist inguishable f rom t hat of ot her c auses of c onsolidat ion suc h as aspirat ion, edema, and pneumonia. CT demonst rat ion of loc alized, pat c hy inf ilt rat es neighboring a rib f rac t ure or c hest - w all hemat oma suggest s c ont usion, w hereas inf ilt rat es predominant ly loc at ed in t he superior segment s of bot h low er lobes and ot her dependent segment s suggest aspirat ion (438).

F igure 21- 9 Pulmonary c ont usion. Comput ed t omography image t hrough t he c arina of a y oung w oman st ruc k by an aut omobile demonst rat es nonsegment al areas of parenc hy mal c onsolidat ion and ground- glass densit y in t he right lung. T hic k ar r ow , lef t c hest t ube; t hin ar r ow , rib f rac t ure; H, hemot horax.

Alt hough CT is c apable of demonst rat ing earlier, as w ell as more ext ensiv e, pulmonary c ont usion t han c hest radiography , sev eral inv est igat ors hav e quest ioned t he c linic al signif ic anc e of t his improv ed det ec t ion (346,415). In some st udies, only t hose c ont usions diagnosed by c hest radiography prov ed c linic ally signif ic ant (415), and it has been st at ed t hat t he det ec t ion of pulmonary c ont usion on CT should not dic t at e a c hange in c linic al management

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3053 in t he absenc e of hy poxemia or ot her respirat ory dist urbanc es (346). Nev ert heless, ot her inv est igat ors hav e show n t hat CT quant it at ion of pulmonary c ont usion may be usef ul in t he management of pat ient s w it h blunt c hest injury . In a rev iew of 69 pat ient s w it h sev ere blunt c hest t rauma examined by CT w it hin 24 hours of admission, it w as f ound t hat w hen t here w as CT ev idenc e of pulmonary c ont usion inv olv ing great er t han 28% of t he t ot al lung v olume, v ent ilat ory support w as inv ariably required (460). Anot her report f ound t hat pat ient s w it h great er t han or equal t o 20% pulmonary c ont usion v olume w ere at signif ic ant ly higher risk of dev eloping ARDS (281).

Pulmonary Laceration, Pneumatocele, and Hematoma Pulmonary lac erat ion is a t ear in t he lung parenc hy ma t hat dev elops t hrough any of t he f our major mec hanisms of blunt injury desc ribed earlier (i.e., direc t impac t , inert ial dec elerat ion, spallat ion, implosion) or f rom any penet rat ing injury , suc h as f rom sharp, depressed rib f ragment s. T he init ial linear or st ellat e t ear of a lac erat ion t ends t o f orm an ov oid- or ellipt ic al- shaped post lac erat ion spac e bec ause of elast ic rec oil of t he adjac ent int ac t lung (300). Conc omit ant t ears of bronc hi and blood v essels may f ill t he post lac erat ion spac e w it h air (pneumat oc ele), blood (hemat oma), or bot h (hemat opneumat oc ele) (158). Pat hologic ally , lac erat ions are lined by c ompressed alv eoli and c onnec t iv e P.1425 t issue remnant s, and may be uni- or mult iloc ular, generally v ary ing f rom 2 c m t o 14 c m in diamet er (291,300). Radiographic ally , pulmonary lac erat ions appear as c irc umsc ribed areas c ont aining air, f luid, or bot h. T hey are of t en obsc ured init ially by surrounding pulmonary c ont usion and may bec ome more apparent as t he c ont usion resolv es. If t he lac erat ion bec omes f illed w it h blood and a pulmonary hemat oma f orms, it c an present as a f oc al mass on c hest radiography , mimic king a primary lung c anc er. CT is c onsiderably more sensit iv e t han c hest radiography in det ec t ing pulmonary lac erat ion. In a series of 85 c onsec ut iv e c hest t rauma v ic t ims, CT det ec t ed 99 lac erat ions c ompared w it h only 5 det ec t ed by radiography (459). Bec ause of t he f requent CT ident if ic at ion of pulmonary lac erat ion f ollow ing blunt t rauma, it has been suggest ed t hat pulmonary lac erat ion is t he basic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3054 mec hanism of injury in pulmonary c ont usion, pulmonary hemat oma, and t raumat ic pulmonary c y st , as w ell as t he c ause of most c av it ies in areas of pulmonary c ont usion (459) (F ig. 21- 10). In c ases of sev ere blunt c hest t rauma, mult iple t raumat ic lac erat ions and air c y st s may be seen w it hin an area of air–spac e c onsolidat ion, giv ing rise t o t he so- c alled “ pulv erized” lung appearanc e on CT images (233) (F ig. 21- 11). Pulmonary lac erat ions c an be div ided int o f our t y pes on t he basis of CT c rit eria and mec hanism of injury (233,436,454,459). T y pe 1 lac erat ions, t he most c ommon t y pe seen on CT , result f rom sudden c ompression of a pliable c hest w all, c ausing rupt ure of air- c ont aining lung. T hey usually appear on CT as int raparenc hy mal c av it ies w it h or w it hout an air–f luid lev el (F ig. 21- 12). On oc c asion, t hey may appear as air- f illed linear st ruc t ures ext ending t hrough t he v isc eral pleura, result ing in a pneumot horax. T y pe 2 lac erat ions are relat iv ely unc ommon and present as air- c ont aining c av it ies or int raparenc hy mal air–f luid lev els w it hin t he basilar parav ert ebral lung (F ig. 21- 13). T hey result f rom sudden c ompression of t he more pliable low er c hest w all, w hic h c auses t he low er lobe t o shif t suddenly ac ross t he spine, produc ing a shearing- t y pe injury . T y pe 3 lac erat ions appear as small peripheral c av it ies or linear luc enc ies neighboring a f rac t ured rib t hat has punc t ured t he underly ing lung. T hese lac erat ions are usually assoc iat ed w it h a pneumot horax. T y pe 4 lac erat ions are rare and oc c ur at sit es of pleuroparenc hy mal adhesion, w hic h c auses t he lung t o t ear w hen t he ov erly ing c hest w all is v iolent ly mov ed inw ard or is f rac t ured. T hese lac erat ions c an be diagnosed only surgic ally or at aut opsy (459).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3055 F igure 21- 11 Pulv erized lung. Comput ed t omography image in a y oung man w ho sust ained sev ere blunt c hest t rauma demonst rat es mult iple t raumat ic lac erat ions and air c y st s (ar r ow s) w it hin an area of right low er lobe c onsolidat ion, result ing in t he so- c alled “ pulv erized” lung appearanc e. A small right pneumot horax is also present .

F igure 21- 10 Pulmonary lac erat ion and c ont usion. Comput ed t omography image t hrough t he low er c hest in a 7- y ear- old girl inv olv ed in a mot or v ehic le ac c ident demonst rat es an air- f illed c av it y (t hic k ar r ow ) represent ing pulmonary lac erat ion w it hin an area of pulmonary c ont usion. An addit ional area of c ont usion is not ed in t he right paraspinal area (t hin ar r ow ).

Most pulmonary lac erat ions resolv e c omplet ely in a period of sev eral w eeks t o mont hs af t er injury , w it h air- f illed lac erat ions (pneumat oc eles) resolv ing more quic kly t han blood- f illed lac erat ions (hemat omas) (54). In mec hanic ally v ent ilat ed pat ient s, post lac erat ion spac es/pneumat oc eles c an progressiv ely enlarge and c ommunic at e w it h t he pleural spac e, result ing in pneumot horax. Rarely , t hey c an bec ome inf ec t ed. CT has been show n t o be superior t o c hest radiography in ident if y ing and f ollow ing t he ev olut ion of t hese lesions and in est ablishing t he presenc e of c omplic at ions suc h as inf ec t ion or hemorrhage (26,211, 400) (F ig. 21- 14).

Aorta and Great Vessels Lac erat ion of t he t horac ic aort a and brac hioc ephalic art eries is a signif ic ant c ause of morbidit y and mort alit y sec ondary t o blunt c hest t rauma. T he majorit y of t hese injuries result f rom high- speed mot or v ehic le ac c ident s. Most of t he remainder are a result of f alls f rom height s and c rush or blast injuries.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3056 Of all aut opsied aut o- ac c ident v ic t ims, about 16% hav e aort ic lac erat ion (157). Lac erat ion is t hought t o result f rom shearing st ress on t he aort a produc ed by dif f erent ial P.1426 dec elerat ion (w hiplash) of t he aort ic root , aort ic arc h, and desc ending aort a at t he t ime of impac t . Sudden inc reases in int raaort ic pressure produc ed by c hest or abdominal w all c ompression may also c ont ribut e t o aort ic injury (256). Anot her hy pot hesis suggest s t hat c ompression of t he aort a bet w een t he st ernum and t he t horac ic spine result s in an “ osseous pinc h” of t he aort a t hat c auses lac erat ion (61,62,73). What ev er t he mec hanism of injury , t he result is t hat one or more lay ers of t he aort ic w all are t orn, usually in a t ransv erse f ashion. T hough t he t ear may be short (f ew millimet ers) and superf ic ial (limit ed t o t he int ima), most are c irc umf erent ial and t ransmural, c onst it ut ing a c omplet e t ransec t ion. When only part of t he aort ic c irc umf erenc e is inv olv ed, t he t ear t ends t o be post erior (335).

F igure 21- 12 Pulmonary lac erat ions f ollow ing blunt c hest t rauma. A: Supine c hest radiograph demonst rat es subt le, f oc al air luc enc y (ar r ow heads) at t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3057 lef t lung base. B, C : Comput ed t omography images rev eal mult iple, bilat eral low er lobe int raparenc hy mal c av it ies c ont aining air–f luid lev els. Surrounding parenc hy mal c ont usion is also ev ident .

F igure 21- 13 Pulmonary lac erat ion f ollow ing f all f rom a height . Comput ed t omography image demonst rat es int raparenc hy mal air- f luid lev el (ar r ow ) w it hin t he basilar parav ert ebral lung.

In c linic al series, ov er 90% of aort ic t ears oc c ur at t he aort ic ist hmus (i.e., t he dist al aort ic arc h at t he insert ion of t he ligament um art eriosum just af t er t he origin of t he lef t subc lav ian art ery ), w hic h is t he sit e of maximum aort ic w all shear st ress. Approximat ely 5% of t ears inv olv e t he asc ending aort a, P.1427 usually just abov e t he aort ic v alv e (78,223,255,372). In aut opsy series, t he inc idenc e of asc ending aort ic t ears is higher (20% t o 25%), ref lec t ing t he f ac t t hat t ears of t he asc ending aort a are almost alw ay s immediat ely f at al (335,431). Deat h is usually a result of assoc iat ed c ardiac injuries. Sev ere c ardiac injuries, suc h as my oc ardial c ont usion, aort ic v alv e rupt ure, c oronary art ery lac erat ion, and hemoperic ardium w it h c ardiac t amponade, are present in 75% of pat ient s w it h asc ending aort ic lac erat ion, c ompared w it h only 25% of pat ient s w it h aort ic ist hmus lac erat ion (335). Most v ic t ims of c ombined asc ending aort ic lac erat ion and c ardiac injury hav e been pedest rians, ejec t ed passengers, or suf f erers of f alls, inc luding airplane c rashes and elev at or ac c ident s (157,335,431). Injuries t o t he desc ending aort a f rom blunt t rauma are rare. When lac erat ion of t he desc ending aort a does oc c ur, it is usually at

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3058 t he lev el of t he aort ic hiat us, w here t he dist al desc ending aort a exit s t he t horax t hrough t he diaphragm (425). Mult iple aort ic t ears oc c ur in 6% t o 19% of c ases (157,335), and assoc iat ed injury or av ulsion of t he brac hioc ephalic art eries has been report ed in 4% of c ases (125). Brac hioc ephalic injuries are of t en mult iple, oc c urring muc h more c ommonly in assoc iat ion w it h ot her aort ic or brac hioc ephalic lac erat ions t han as single- art ery insult s (125).

F igure 21- 14 Inf ec t ed hemat oma. A: Chest radiograph in f ebrile pat ient t hree w eeks af t er rollov er mot or v ehic le ac c ident demonst rat es mult iple right rib f rac t ures and a large, rounded opac it y c ont aining mult iple loc ules of air in t he right midlung f ield. B: Comput ed t omography image show s large int raparenc hy mal mass c ont aining f luid and air c ompat ible w it h an inf ec t ed hemat oma or lung absc ess. A small amount of subc ut aneous air is present in t he right post erior c hest w all.

Eight y perc ent t o ninet y perc ent of all pat ient s w it h aort ic lac erat ion die at t he sc ene of t he ac c ident or bef ore t hey c an be t ransport ed t o a hospit al and t reat ed (335). F or t he remaining 10% t o 20% w ho arriv e at a hospit al aliv e, expedient diagnosis and immediat e surgic al repair generally are essent ial t o prev ent exsanguinat ing hemorrhage at t he sit e of t he aort ic t ear. T he import anc e of rapid diagnosis and t reat ment in t his group of pat ient s is undersc ored by t he f ac t t hat surv iv al rat es ranging f rom 68% t o 80% hav e been report ed if t imely surgic al repair c an be perf ormed (58,68,223,227,381). Wit hout t reat ment , it is est imat ed t hat less t han 5% of pat ient s surv iv e. T hese are usually pat ient s w it h only part ial aort ic t ransec t ion, in w hom t he pulsat ing hemat oma is c ont ained by t he adv ent it ia or t he periaort ic t issues (335).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3059 Clinic al f indings in pat ient s w it h t raumat ic aort ic lac erat ion are f requent ly absent , and t he possibilit y of aort ic injury is of t en init ially raised solely on t he basis of a hist ory of t rauma inv olv ing signif ic ant dec elerat ion (i.e., high- speed mot or v ehic le ac c ident ). More t han 50% of pat ient s w it h aort ic lac erat ion may hav e no v isible ext ernal signs of c hest t rauma. F urt hermore, it may be impossible t o elic it sy mpt oms in a subst ant ial number of t hese pat ient s bec ause of alt ered ment al st at us result ing f rom c onc omit ant head t rauma (231). T he most c ommon c omplaint in t he immediat e post injury period is ret rost ernal or int ersc apular pain, t hought t o be a result of mediast inal dissec t ion of blood. Less f requent ly enc ount ered signs and sy mpt oms inc lude dy spnea, dy sphagia, upper ext remit y hy pert ension, low er ext remit y hy pot ension, and a harsh sy st olic murmur ov er t he prec ordium or int ersc apular area (bec ause of t urbulent f low ac ross t he area of t ransec t ion). Unf ort unat ely , none of t hese c linic al f indings are suf f ic ient ly sensit iv e or spec if ic t o be c onsidered diagnost ic of aort ic injury (223). P.1428 T he diagnosis of aort ic injury is usually suggest ed by f indings on c hest radiography and t hen c onf irmed by MDCT and/or t horac ic aort ography . Radiographic f indings suggest iv e of ac ut e aort ic t rauma primarily ref lec t t he presenc e of mediast inal hemat oma and may inc lude (a) w idening of t he superior mediast inum; (b) f ullness, def ormit y , or obsc urat ion of t he aort ic c ont our, part ic ularly in t he region of t he aort ic arc h, ist hmus, or aort opulmonary w indow ; (c ) dev iat ion of t he t rac hea or nasogast ric t ube in t he esophagus t o t he right ; (d) c audal displac ement of t he lef t main st em bronc hus; (e) w idening of t he right parat rac heal st ripe; (f ) w idening of t he parav ert ebral st ripes; and (g) ext rapleural ext ension of hemorrhage ov er t he lung apex (apic al c ap) (284,406,437,485). Of t hese numerous f indings, w idening of t he mediast inum w it h loss of t he aort ic c ont our is t he most sensit iv e predic t or of aort ic injury , and t he most f requent indic at ion f or aort ography (15,162, 231,389). Isolat ed f rac t ures of t he f irst and/or sec ond ribs, onc e t hought t o indic at e sev ere mediast inal t rauma, do not c orrelat e w it h aort ic rupt ure and are not , by t hemselv es, an indic at ion f or aort ography in t he absenc e of radiographic or CT ev idenc e of mediast inal hemat oma (126,239,484). Alt hough t he c hest radiograph has a high sensit iv it y f or mediast inal hemat oma, it is f requent ly f alsely posit iv e as a result of a v ariet y of f ac t ors, inc luding shallow inspirat ion, supine ant eropost erior posit ioning, v asc ular ec t asia,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3060 pulmonary disease adjac ent t o t he mediast inum, and mediast inal f at . It is import ant t o not e t hat , ev en w hen mediast inal hemorrhage is c orrec t ly diagnosed, it is most c ommonly c aused by disrupt ion of small art eries and v eins in t he mediast inum, rat her t han by aort ic injury (10,328). Mediast inal hemat oma may also result f rom nonaort ic hemorrhage assoc iat ed w it h ot her mediast inal injuries, suc h as t rac heobronc hial t ears or f rac t ures of t he low er c erv ic al and upper t horac ic spine (86). A c omplet ely normal c hest radiograph is of great er diagnost ic signif ic anc e t han an abnormal c hest radiograph, sinc e it has a 98% negat iv e predic t iv e v alue f or t raumat ic aort ic or brac hioc ephalic art ery rupt ure (264,285,483). Aort ography is a w ell- est ablished met hod of diagnosing t raumat ic aort ic lac erat ion and of def ining it s anat omic ext ent . It is used liberally in t rauma pat ient s bec ause t he c onsequenc es of missing an aort ic rupt ure are grav e, t he c linic al f indings are f requent ly absent , and t he radiographic f indings are nonspec if ic . Only 10% t o 20% of pat ient s w it h c linic al and radiographic f indings suggest iv e of aort ic t rauma hav e angiographic c onf irmat ion of an aort ic t ear (162,285,433,454). Angiographic ally , lac erat ions appear as sharply def ined linear luc enc ies, produc ed by t he inf olded, t orn edges of t he int ima. Assoc iat ed irregularit y of t he aort ic w all and/or a f alse aneury sm may also be seen. Conv ent ional aort ography has been report ed t o hav e a 100% sensit iv it y and 99% spec if ic it y f or t he diagnosis of t raumat ic aort ic injury , w it h a posit iv e predic t iv e v alue of 97% and a negat iv e predic t iv e v alue of 100% (433). Similar suc c ess rat es hav e been ac hiev ed using int raart erial digit al subt rac t ion aort ography , w hic h, in c omparison t o c onv ent ional aort ography , c an reduc e bot h t he amount of t ime and t he amount of int rav asc ular c ont rast mat erial needed t o obt ain a diagnost ic ally ac c urat e st udy (290). T he role of CT in t he ev aluat ion of pat ient s w it h suspec t ed injury of t he aort a c ont inues t o ev olv e. Init ially , CT w as used primarily as an adjunc t t o c hest radiography in det ermining t he need f or aort ography (4,260,289,307,352,357). Some quest ioned t he ac c urac y of CT f indings and t he v alidit y of CT usage in t his regard, st at ing t hat CT only delay ed perf ormanc e of aort ography or def init iv e t reat ment w it h surgery (279,471). CT has t y pic ally been perf ormed on hemody namic ally st able pat ient s w it h a c linic al suspic ion of aort ic t ear in w hom c hest radiographic f indings are equiv oc al (307). In suc h pat ient s, CT c an ac c urat ely exc lude t he presenc e of mediast inal hemorrhage or prov ide alt ernat iv e explanat ions f or equiv oc al radiographic f indings, t hus eliminat ing t he need f or aort ography . Apparent mediast inal w idening on c hest radiographs,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3061 f or example, may be show n on CT t o represent exc essiv e mediast inal f at (F ig. 21- 15), parav ert ebral pleural ef f usion, at elec t at ic /c ont used lung adjac ent t o t he mediast inum, v asc ular ec t asia, or c ongenit al v asc ular anomalies suc h as right aort ic arc h, persist ent lef t superior v ena c av a, or hemiazy gous c ont inuat ion of t he inf erior v ena c av a (373,419,439,442). Chest CT has also been used as an anc illary sc reening modalit y f or aort ography in c linic ally st able pat ient s requiring CT examinat ion f or anot her indic at ion (e.g., ev aluat ion of int rac ranial or abdominal t rauma) (307,352). In a met aanaly sis ev aluat ing t he c ost - ef f ec t iv eness of using CT t o t riage pat ient s t o aort ography , t he addit ion of c hest CT in pat ient s requiring head or abdominopelv ic CT f or ev aluat ion of ot her injuries w as f ound t o be bot h medic ally ef f ec t iv e and c ost reduc ing (105,194). Most st udies t o dat e suggest t hat an unequiv oc ally normal c hest CT reliably exc ludes aort ic injury , w it h an ov erall f alse–negat iv e CT rat e of approximat ely 1% (4,122,124, 260,279,289,307,352,357,472). F alse–negat iv e CT st udies hav e been at t ribut ed t o c ont ained int imal and/or medial t ears unassoc iat ed w it h mediast inal hemorrhage, or t o t ec hnic ally subopt imal examinat ions degraded by mot ion art if ac t or inadequat e c ont rast mat erial administ rat ion (307). By exc luding mediast inal hemorrhage or prov iding alt ernat iv e explanat ions f or mediast inal w idening, CT has been report ed in a number of st udies t o reduc e t he need f or aort ography in selec t ed t rauma pat ient s by 50% t o 73% (198,260,289,307,352,357). Anot her st udy , how ev er, report ed t hat t he “ absolut e exc lusion” of mediast inal hemorrhage by CT w as of t en dif f ic ult and result ed in only a 25% reduc t ion in t he use of aort ography (124). CT c an demonst rat e bot h direc t and indirec t (i.e., mediast inal hemorrhage) ev idenc e of aort ic injury . Some aut hors c onsider t he presenc e of mediast inal hemorrhage on CT t o be an indic at ion f or aort ography , ev en in t he absenc e of direc t signs of aort ic injury (289,307,357,492). P.1429 T he mediast inal hemorrhage may be f oc al or dif f use and appears on CT as homogeneous areas of f luid w it hin t he mediast inum or as st reaky t issuedensit y f luid inf ilt rat ing t he mediast inal f at (124,307,352) (F ig. 21- 16). Dif f ic ult ies in int erpret at ion may arise bec ause of t he c onf usion of mediast inal hemorrhage w it h t hy mic t issue in t he ant erior mediast inum, part ial v olume av eraging of t he pulmonary art ery in t he aort opulmonary w indow , periaort ic at elec t asis in t he lef t low er lobe, or mot ion art if ac t produc ing haziness in t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3062 mediast inum (351,357,471). T he majorit y of pat ient s w it h CT ev idenc e of mediast inal hemorrhage do not hav e angiographic ev idenc e of an aort ic t ear (124,307,352,357). As ment ioned prev iously , mediast inal hemorrhage is merely a marker of signif ic ant mediast inal t rauma and is not spec if ic f or aort ic injury . Most c ommonly , t he bleeding is f rom disrupt ion of mediast inal v eins and/or small art eries rat her t han f rom aort ic rupt ure (10).

F igure 21- 15 Mediast inal lipomat osis. A: Chest radiograph demonst rat es mediast inal w idening in a 40- y ear- old w oman f ollow ing a mot or v ehic le ac c ident . B: Comput ed t omography image at t he lev el of t he aort ic arc h demonst rat es abundant mediast inal f at ac c ount ing f or t he mediast inal w idening.

F igure 21- 16 Mediast inal hemorrhage sec ondary t o aort ic lac erat ion. A: Comput ed t omography image t hrough t he lev el of t he aort ic arc h (A) demonst rat es ext ensiv e periaort ic mediast inal hemat oma (h) and irregular

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3063 t ears (ar r ow heads) in t he aort ic w all. T he t rac hea (T ) and t he nasogast ric t ube w it hin t he esophagus are shif t ed t o t he right . B: Digit al subt rac t ion angiographic image c onf irms t he presenc e of ext ensiv e aort ic lac erat ion (ar r ow heads), beginning just dist al t o t he origin of t he lef t subc lav ian art ery .

F igure 21- 17 Aort ic lac erat ion in a 56- y ear- old w oman inv olv ed in a mot or v ehic le ac c ident . A, B: Comput ed t omography sec t ions t hrough t he aort ic arc h (A) and proximal desc ending t horac ic aort a demonst rat e periaort ic mediast inal hemorrhage and a f oc al inc rease in c aliber of t he aort ic lumen w it h marked irregularit y of t he aort ic margins (ar r ow heads). Right lung c ont usion and small lef t pleural ef f usion are also ev ident . T here is st reak art if ac t f rom t he nasogast ric t ube in t he esophagus and f rom mult iple median st ernot omy sut ure w ires. S, superior v ena c av a. C : Angiography c onf irms t he presenc e of aort ic lac erat ion (ar r ow ) just dist al t o t he origin of t he lef t subc lav ian art ery .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3064 P.1430 Direc t CT f indings of aort ic injury inc lude pseudoaneury sm, int imal f lap, aort ic c ont our def ormit y (F ig. 21- 17), abrupt t apering of t he desc ending aort a relat iv e t o t he asc ending aort a (“ pseudoc oarc t at ion” ), and ac t iv e ext rav asat ion of c ont rast mat erial (127,137,138,172,174,265,378, 468,492). T he pseudoaneury sm may be f oc al or c irc umf erent ial, and c an be ident if ied on CT as a sac c ular out pouc hing or inc rease in c aliber of t he aort ic lumen c ompared w it h t he more proximal normal aort a (F ig. 21- 18). An int imal f lap produc ed by t he t orn edge of t he aort ic w all appears on CT as a small, linear, low - densit y int raluminal f illing def ec t w it hin t he opac if ied aort ic lumen (F ig. 21- 19). In injuries in w hic h t he aort ic adv ent it ia is breac hed, ext rav asat ion of c ont rast mat erial c an oc c ur, ranging f rom small leaks t o gross ext rav asat ion. In a prospec t iv e series examining t he ef f ic ac y of CT f or direc t det ec t ion of t raumat ic aort ic injury , helic al CT w as f ound t o hav e an ov erall diagnost ic ac c urac y of nearly 100% (293). In a separat e large series using helic al sc anning exc lusiv ely t o sc reen 1,518 pat ient s w it h blunt c hest t rauma, helic al CT w it h t hin ov erlapping rec onst ruc t ion w as f ound t o be 100% sensit iv e and 81.7% spec if ic in det ec t ing aort ic injury (138). Adv anc es in MDCT t ec hnology are likely t o f urt her improv e our abilit y t o ev aluat e t he aort a f or direc t signs of injury (6).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3065 F igure 21- 18 Aort ic lac erat ion. A, B: Comput ed t omography images t hrough t he aort ic arc h (A) and proximal desc ending aort a at t he lev el of t he c arina demonst rat e a t ear (ar r ow s) in t he aort ic w all and an assoc iat ed pseudoaneury sm (ast er isk). T here is a right c hest t ube (c t ) w it h adjac ent hemat oma and at elec t at ic lung. AA, asc ending aort a; S, superior v ena c av a. C : Sagit t al rec onst ruc t ion bet t er separat es t he t rue aort ic lumen f rom t he pseudoaneury sm (ast er isk).

F igure 21- 19 Aort ic lac erat ion. A, B: Comput ed t omography images t hrough t he lev el of t he aort ic arc h (A) and main pulmonary art ery (PA) demonst rat e periaort ic mediast inal hemorrhage (h), irregularit y of t he aort ic c ont our, and linear luc enc ies (ar r ow s) w it hin t he opac if ied aort ic lumen, represent ing int imal f laps produc ed by t he t orn edges of t he aort ic w all. T he t rac hea (t ) and esophagus (c ont aining a nasogast ric t ube) are shif t ed t o t he right by t he mediast inal hemat oma. A lef t c hest t ube and adjac ent parenc hy mal at elec t asis are also present . AA, asc ending aort a; S, superior v ena c av a.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3066 F igure 21- 20 Aort ic lac erat ion. A: T ransaxial c omput ed t omography image at t he lev el of t he aort ic arc h demonst rat es marginal irregularit y of t he aort ic w all (ar r ow ) w it h adjac ent periaort ic hemorrhage. Blood is not ed in bot h pleural c av it ies. L, c onsolidat ed lung parenc hy ma. B: Sagit t al image c onf irms t he subt le f oc al abnormalit y (ar r ow ).

F igure 21- 21 Post t raumat ic aort ic pseudoaneury sm in a 21- y ear- old man approximat ely t w o y ears f ollow ing a mot or v ehic le ac c ident and repair of a rupt ured lef t hemidiaphragm. A– C : Comput ed t omography images demonst rat e a pseudoaneury sm (ar r ow ) projec t ing medially f rom t he proximal desc ending aort a (DA). T he dist al aort ic arc h and desc ending aort a are displac ed superiorly and lat erally by t he pseudoaneury sm. T he pat ient underw ent suc c essf ul surgic al repair w it h plac ement of an aort ic t ube graf t . AA, asc ending aort a; S, superior v ena c av a; T , t hy mus.

P.1431

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3067 P.1432 P.1433 Pat ient s w it h obv ious direc t signs of aort ic injury on CT may be t aken direc t ly t o surgery w it hout c onf irmat ory aort ography (100,137,351,382,445). Subt le c ont our abnormalit y seen on a t ransaxial sec t ion may be bet t er demonst rat ed on sagit t al or c oronal images (F ig. 21- 20). Equiv oc al or less spec if ic CT f indings, suc h as marginal irregularit y of t he aort ic w all or isolat ed periaort ic hemat oma, generally st ill w arrant aort ography . If t he aort a is only part ially t ransec t ed f ollow ing blunt t rauma and t he pat ient surv iv es w it hout rec ognit ion and t reat ment , a loc alized f alse (pseudo) aneury sm may subsequent ly dev elop ov er a period of mont hs t o y ears. T hese lesions, w hic h c ont inue t o c ommunic at e w it h t he aort ic lumen t hrough t he t ear and t end t o expand w it h t ime, are most c ommonly f ound immediat ely dist al t o t he origin of t he lef t subc lav ian art ery , in t he region of t he aort ic ist hmus. T hey hav e been est imat ed t o oc c ur in 2% t o 5% of pat ient s w it h aort ic injury and may be det ec t ed inc ident ally on plain c hest radiography or bec ause of sy mpt oms relat ed t o t heir expansion (20,123,335). Cont rary t o t he assessment of ac ut e t raumat ic injury of t he aort a, eit her CT or MRI usually is adequat e f or diagnost ic c onf irmat ion of a c hronic t raumat ic pseudoaneury sm suspec t ed on plain c hest radiography , and aort ography is rarely required. On CT or MRI, a c hronic t raumat ic pseudoaneury sm appears as sac c ular or f usif orm dilat at ion of t he aort ic ist hmus (F ig. 21- 21). Peripheral c alc if ic at ion of t he w all of t he pseudoaneury sm may be seen on CT (53) (F ig. 21- 22). Sagit t al MR images hav e been report ed t o be helpf ul in def ining t he exac t relat ionship of t he pseudoaneury sm t o t he lef t subc lav ian art ery and in det ermining t he size of it s c ommunic at ion w it h t he aort ic lumen (302). Bec ause of t he persist ent risk of rupt ure of t hese post t raumat ic aneury sms, endov asc ular st ent graf t repair or elec t iv e surgic al exc ision is generally perf ormed (6,20,123,176).

Heart and Pericardium Blunt c hest t rauma c an result in a spec t rum of c ardiac injuries, ranging in sev erit y f rom inc onsequent ial, asy mpt omat ic lesions t hat are det ec t able only by serial elec t roc ardiograms (ECGs) t o rapidly f at al c ardiac rupt ure. Ac ut e heart injuries inc lude c ont usion, t ransmural my oc ardial nec rosis, and lac erat ion or rupt ure of t he peric ardium, my oc ardium, sept a, papillary musc les, c ardiac v alv es, and c oronary art eries (97,225,334). Alt hough t he exac t inc idenc e of c ardiac injury f rom blunt c hest t rauma is unknow n, aut opsy series hav e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3068 demonst rat ed t hat great er t han 10% of highw ay f at alit ies hav e ev idenc e of c ardiac damage, and t hat in approximat ely 5%, t he c ardiac injury is let hal (326,414). In c linic al series, est imat es of c ardiac injury as high as 76% hav e been report ed among selec t ed groups of sev erely injured pat ient s (405). My oc ardial c ont usion represent s t he most c ommon manif est at ion of c ardiac t rauma and has been report ed t o oc c ur in 8% t o 76% of pat ient s f ollow ing sev ere c hest injury (181). It result s in my oc ardial edema, hemorrhage, and nec rosis, and an inc rease in t he MB f rac t ion of t he enzy me c reat ine phosphokinase (CPK). ECG c hanges are similar t o t hose of my oc ardial isc hemia and inf arc t ion. Delay ed onset of right v ent ric ular c ont rac t ions, loc alized w allmot ion abnormalit ies, and depressed ejec t ion f rac t ion on ECG- gat ed radionuc lide blood pool sc ans hav e also been observ ed (240,369). T he right v ent ric le is t he most f requent ly injured bec ause it makes up t he majorit y of t he exposed ant erior surf ac e of t he heart direc t ly behind t he st ernum. Clinic ally , my oc ardial c ont usion usually is w ell t olerat ed. How ev er, t he result ant my oc ardial damage P.1434 c an lead t o f unc t ional c ardiac abnormalit ies suc h as diminished c ardiac out put or ac ut e c ardiac arrhy t hmias in up t o 20% of pat ient s (187).

F igure 21- 22 Post t raumat ic aort ic pseudoaneury sm in a pat ient w it h a remot e hist ory of a mot or v ehic le ac c ident requiring hospit alizat ion. A, B: Comput ed t omography images demonst rat e f oc al aort ic pseudoaneury sm w it h peripheral c alc if ic at ion (ast er isk). T here are bilat eral pleural ef f usions, lef t great er t han right . AA, asc ending aort a; DA, desc ending aort a.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3069

F igure 21- 23 Ac ut e t raumat ic hemoperic ardium. Nonc ont rast c omput ed t omography image demonst rat es high- at t enuat ion peric ardial ef f usion (ar r ow s) c onsist ent w it h ac ut e peric ardial hemorrhage.

Cardiac dy sf unc t ion result ing f rom blunt t rauma is f requent ly missed or det ec t ed lat e bec ause t he c ardiac injury (e.g., c ont usion) is of t en masked by ot her more obv ious mult isy st em injuries and bec ause rout ine t est s, suc h as ECGs and CPK isoenzy me det erminat ions, are nonspec if ic f ollow ing sev ere t rauma (28,369). Chest radiography and CT play only a minor role in t he ev aluat ion of my oc ardial injury . Radiographic f indings may inc lude ev idenc e of c ongest iv e f ailure, suc h as c ardiac enlargement and pulmonary edema. T he presenc e of ant erior rib f rac t ures and st ernal f rac t ures should inc rease c linic al suspic ion of my oc ardial injury , alt hough t here is no c lear relat ionship bet w een t he ext ent of c hest w all injury and t he degree of underly ing c ardiac damage (295). Vent ric ular aneury sms may dev elop as a sequela of c ardiac injury suc h as c ont usion or inf arc t ion, and c an be det ec t ed on CT or c onv ent ional c hest radiographs by a c hange in c ardiac c ont our and by t he presenc e of c alc if ic at ion w it hin t he w all of t he aneury sm (154). Ac ut e hemoperic ardium c an oc c ur f ollow ing injury t o t he heart or peric ardium. CT is v ery sensit iv e f or det ec t ing peric ardial spac e f luid and may indic at e t he presenc e of peric ardial hemorrhage by t he high CT at t enuat ion (i.e., near sof t

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3070 t issue densit y ) of t he f luid (429) (F ig. 21- 23). Small hemorrhagic peric ardial ef f usions of no f unc t ional signif ic anc e are somet imes seen as inc ident al f indings on post t raumat ic CT examinat ions. Rapid ac c umulat ion of blood in t he peric ardial spac e c an lead t o c ardiac t amponade and sev ere hemody namic c ompromise. T he diagnosis of ac ut e t amponade is usually est ablished by t he presenc e of c linic al signs suc h as t ac hy c ardia, elev at ed c ent ral v enous pressure, dist ended nec k v eins, muf f led c ardiac sounds, and diminished c ardiac out put . Emergenc y bedside sonographic ev aluat ion of t he heart c an doc ument t he presenc e of peric ardial ef f usion prior t o prompt peric ardioc ent esis or peric ardiot omy . CT f indings of ac ut e t amponade f ollow ing blunt t rauma inc lude hemorrhagic P.1435 peric ardial f luid, dist ended c ent ral v eins (e.g., v ena c av ae, hepat ic v eins, renal v eins), and periport al ly mphedema w it hin t he liv er (152).

F igure 21- 24 Post t raumat ic pneumoperic ardium. Comput ed t omography image at t he lev el of t he right hemidiaphragm demonst rat es a small amount of peric ardial air (ar r ow ). Parenc hy mal c ont usion is ev ident at bot h lung bases, right great er t han lef t .

Pneumoperic ardium is an unc ommon manif est at ion of blunt c hest t rauma and is t hought t o result f rom dissec t ion of air along periv asc ular and/or peribronc hial sheat hs int o t he peric ardium. Air f rom rupt ured alv eoli, f or example, c an t rac k along t he adv ent it ia of t he pulmonary v eins and ent er t he peric ardial spac e (258,262). Moderat ely small amount s of peric ardial air are generally of lit t le c linic al signif ic anc e, and may be det ec t ed inc ident ally on CT (F ig. 21- 24). Rarely , larger amount s of air c an c ompress t he heart and lead t o t he dev elopment of t ension pneumoperic ardium. Radiographic ally t his is manif est ed

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3071 by a sudden, subst ant ial dec rease in size of t he c ardiac silhouet t e in t he presenc e of pneumoperic ardium and c linic al signs of c ardiac t amponade (287). Prolonged posit iv e airw ay pressure in c ombinat ion w it h pulmonary c ont usion, pneumot horax, or t rac heobronc hial t ear may inc rease t he dev elopment of t his c omplic at ion. Peric ardial rupt ure is a rare sequela (less t han 0.5%) of sev ere blunt c hest t rauma (135). Rupt ure may inv olv e t he diaphragmat ic peric ardium and/or t he pleuroperic ardium, most c ommonly on t he lef t . T he diagnosis is usually made int raoperat iv ely or at aut opsy . Ant emort em diagnosis may be suggest ed by c hest radiographic or CT f indings of herniat ion of air- c ont aining abdominal v isc era int o t he peric ardium ac c ompany ing diaphragmat ic rupt ure (295). Addit ional CT f indings t hat hav e been report ed in pat ient s w it h t raumat ic peric ardial rupt ure inc lude pneumoperic ardium, post erolat eral rot at ion of t he c ardiac apex, and ext rusion of t he heart t hrough t he peric ardial t ear (222).

Trachea and Bronchi T rac heobronc hial t ear is an unc ommon but serious c omplic at ion of blunt c hest t rauma, w it h an est imat ed ov erall mort alit y of 30% (224). Most t ears inv olv e t he dist al t rac hea (15%) or proximal mainst em bronc hi (80%) (477), w it h more t han 80% of all t ears oc c urring w it hin 2.5 c m of t he c arina (224). T he c linic al and radiographic f indings v ary , depending on t he sit e and ext ent of t he t ear. Complet e t ears of t he right mainst em and dist al lef t mainst em bronc hi generally manif est as pneumot horax. T he pneumot horax t ends t o be large and unreliev ed by c hest t ube drainage. T ears of t he t rac hea and proximal lef t mainst em bronc hus usually result in pneumomediast inum. T he pneumomediast inum is of t en sev ere, persist ent , and progressiv e, w it h w idespread dissec t ion of air int o t he nec k and subc ut aneous t issues. Inc omplet e t rac heobronc hial t ears w it h int ac t perit rac heal and peribronc hial adv ent it ia may not be assoc iat ed w it h pneumot horax, pneumomediast inum, or ot her radiographic f indings. T his is bec ause t he int egrit y of t he airw ay is init ially maint ained, prev ent ing passage of air int o t he mediast inum or pleura. Suc h part ial t ears may remain oc c ult unt il subsequent high- pressure mec hanic al v ent ilat ion c auses mediast inal emphy sema or delay ed massiv e pneumot horax (158). Alt hough t he f indings of t rac heobronc hial t ear are somet imes subt le and ov ershadow ed by ot her injuries, t he diagnosis is usually suggest ed by t he presenc e of dy spnea, persist ent pneumot horax or air leak f ollow ing c hest t ube

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3072 drainage, and massiv e or rapidly inc reasing mediast inal or subc ut aneous emphy sema (182). Abnormalit ies in posit ion and c onf igurat ion of an endot rac heal t ube, inc luding ov erdist ent ion of t he balloon c uf f or ext raluminal posit ion of t he t ip, may be seen in pat ient s w it h t rac heal rupt ure (365,451). In c omplet e bronc hial t ear w it h assoc iat ed pneumot horax, t he c ollapsed lung may f all aw ay f rom t he hilum t ow ard t he most dependent port ion of t he hemit horax, giv ing rise t o t he so- c alled “ f alling lung sign” (F ig. 21- 25) (234,322,435,476). T his is t he rev erse of t he usual f inding in unc omplic at ed pneumot horax, in w hic h t he lung is t et hered by t he hilum and c ollapses t ow ard it . T he disrupt ed bronc hus may be def ormed (i.e., sharply angulat ed) or obst ruc t ed. Bot h t he presenc e of t he “ f alling lung sign” and endot rac heal t ube abnormalit ies suc h as an ov erdist ended balloon c uf f are c onsidered reliable t hough unc ommon indic at ors of airw ay injury (451). CT c an be used t o diagnose t rac heal t ears in pat ient s w it h indw elling endot rac heal t ubes by demonst rat ing ext raluminal t ip posit ion or by show ing an ov erdist ended balloon prot ruding t hrough t he t rac heal t ear int o t he mediast inum (52,438). T he ac t ual rent in t he t rac heal w all may be seen ev en in t he absenc e of endot rac heal t ube abnormalit y (329). Assoc iat ed mediast inal and subc ut aneous emphy sema are also w ell depic t ed on CT . Bronc hial rupt ure has been rec ognized on CT by abrupt t apering of t he injured bronc hus, c oupled w it h shif t of t he mediast inum t ow ard t he c ompromised lung and ret rac t ion of t he t rac hea in t he opposit e direc t ion (465). Alt hough CT is c apable of demonst rat ing t rac heobronc hial injury , t he st andard c hest radiograph and appropriat e c linic al f indings are usually enough t o suggest urgent bronc hosc opy , w hic h generally is required f or def init iv e diagnosis prior t o surgery (154). In a f ew selec t c ases of t rac heal rupt ure, diagnost ic f indings on CT examinat ion hav e led t o immediat e surgic al repair w it hout bronc hosc opy (438).

Esophagus Injury t o t he esophagus f rom blunt c hest t rauma is ext remely unc ommon. When it does oc c ur, it is usually sec ondary t o sev ere c hest and/or abdominal c ompression and is f requent ly assoc iat ed w it h ot her t horac ic injuries, suc h as aort ic rupt ure and c ardiac c ont usion (455). Proposed mec hanisms of esophageal injury in blunt t rauma inc lude sudden elev at ion in esophageal hy drost at ic pressure, c rushing of t he esophagus bet w een t he spine and t rac hea, t earing result ing f rom hy perext ension (part ic ularly at t he lev el of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3073 diaphragmat ic hiat us), and direc t penet rat ion by c erv ic al spine f rac t ure f ragment s (291). Ot her c auses of esophageal injury in t he ac ut e t rauma set t ing inc lude inadv ert ent esophageal int ubat ion and t raumat ic nasogast ric t ube plac ement . T he v ast majorit y of t raumat ic esophageal perf orat ions P.1436 are c aused by iat rogenic int erv ent ions suc h as endosc opy , t ube plac ement , or esophageal dilat at ion (154).

F igure 21- 25 T raumat ic rupt ure of t he right main st em bronc hus. A, B: Comput ed t omography images at t he lev el of t he aort ic arc h (A) demonst rat e bilat eral pneumot horac es, pneumomediast inum, and ext ensiv e subc ut aneous emphy sema. T he c ollapsed right lung (L) has f allen aw ay f rom t he hilum t ow ard t he most dependent port ion of t he hemit horax. Pat c hy areas of parenc hy mal c ont usion are not ed in t he lef t lung. S, superior v ena c av a; V, azy gous v ein arc h. (Case c ourt esy of Paul Barry , M.D., Greensboro, Nort h Carolina.)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3074 Radiologic manif est at ions of esophageal rupt ure inc lude pneumomediast inum, c erv ic al emphy sema, pneumot horax, pleural ef f usion, and an abnormal mediast inal c ont our result ing f rom hemorrhage or leakage of gast roesophageal c ont ent s int o t he mediast inum. Early rec ognit ion and prompt medic al and surgic al int erv ent ion is c rit ic al, as esophageal rupt ure may rapidly progress t o f ulminant mediast init is and sept ic shoc k (486). If t here is assoc iat ed rupt ure of t he mediast inal pleura, ac ut e empy ema may also dev elop (159). Oc c asionally , a t rac heoesophageal f ist ula dev elops eit her f rom t he init ial t rauma or as a sequela of t he ac ut e mediast init is. In suc h c ases, t he f ist ula may prot ec t against mediast inal absc ess f ormat ion by prov iding a rout e of drainage f or esophageal c ont ent s (486). Cont rast esophagography is ov er 90% sensit iv e in t he diagnosis of esophageal rupt ure, and is t he proc edure of c hoic e f or est ablishing it s presenc e and ext ent (27). Esophagosc opy has similar diagnost ic sensit iv it y and may prov ide c omplement ary diagnost ic inf ormat ion in selec t c ases (291). CT sc anning has been report ed t o be usef ul in suggest ing t he diagnosis of esophageal perf orat ion in pat ient s w it h at y pic al or c onf using c linic al signs and sy mpt oms (12,467). CT f indings indic at iv e of esophageal perf orat ion inc lude esophageal t hic kening, periesophageal f luid, ext raluminal air, and pleural ef f usion (F ig. 21- 26). Ident if ic at ion of ext raesophageal air is t he most usef ul f inding and is demonst rat ed on CT w it h great er sensit iv it y t han on plain c hest radiographs (467). In some c ases, leakage of oral c ont rast P.1437 mat erial f rom t he disrupt ed esophagus int o t he mediast inum or pleural spac e may be seen (295). CT is also usef ul f or def ining ext raluminal manif est at ions of esophageal rupt ure, suc h as mediast init is, mediast inal absc ess, and empy ema (467). Suc h inf ormat ion of t en has import ant implic at ions f or medic al and/or surgic al management .

Diaphragm Diaphragmat ic rupt ure oc c urs in approximat ely 5% of pat ient s w ho hav e experienc ed major blunt t rauma (277), and 65% t o 85% of diaphragmat ic rupt ures are on t he lef t side (215,277,305,363,469). Lef t - sided injury predominat es bec ause of t he prot ec t iv e ef f ec t of t he liv er on t he right hemidiaphragm and/or underdiagnosis of right - sided injuries (104,177). Proposed mec hanisms of injury in blunt diaphragmat ic rupt ure inc lude shearing of a st ret c hed membrane, av ulsion of t he diaphragm f rom it s point s of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3075 at t ac hment , and abrupt inc rease in t ransdiaphragmat ic pressure f ollow ing sev ere c ompression of t he upper abdomen and low er t horax (215). Injury c an also result f rom direc t lac erat ion of t he diaphragm by f rac t ures of t he low er t horac ic ribs. T he diaphragm most f requent ly rupt ures in t he area of t he c ent ral t endon or at it s t ransit ion t o t he musc ular port ion of t he diaphragm. T he post erior and post erolat eral diaphragmat ic segment s are most c ommonly inv olv ed (383,425). Wit h lac erat ion of t he lef t hemidiaphragm, t he oment um, st omac h, spleen, and small and large bow el c an herniat e int o t he t horax. Wit h t ears of t he right hemidiaphragm, t he liv er is usually t he of f ending organ. Diaphragmat ic rupt ure is of t en unrec ognized at t he t ime of t rauma bec ause of lac k of early herniat ion of abdominal organs int o t he t horax and bec ause t he diaphragmat ic injury is of t en obsc ured or ov ershadow ed by ot her assoc iat ed injuries. Diaphragmat ic rupt ure rarely oc c urs in isolat ion, and a high perc ent age of pat ient s sust ain serious c onc omit ant int raabdominal (59%) or int rat horac ic (45%) injuries (305). In t he absenc e of c harac t erist ic c linic al signs and radiologic f indings at t he t ime of injury , t he c orrec t init ial diagnosis may be made in less t han 50% of c ases. T he diagnosis is most readily made w hen t he injury is rec ent and t he t ear is large and lef t sided w it h herniat ion of hollow abdominal organs. If t he t rauma is remot e or unknow n and t he t ear is right sided w it h herniat ion of solid organs suc h as t he liv er, t he diagnosis is less likely t o be made (13). Not unc ommonly , rec ognit ion of diaphragmat ic t ears may be delay ed f or hours t o y ears, allow ing t ime f or progressiv e herniat ion of abdominal c ont ent s int o t he t horax. Suc h t ears may only be disc ov ered w hen t he pat ient present s w it h c omplic at ions of post t raumat ic herniat ion, suc h as int est inal obst ruc t ion, v isc eral st rangulat ion, and respirat ory impairment (71,76, 155,171). Delay ed present at ion of diaphragmat ic rupt ure w it h v isc eral herniat ion and st rangulat ion is assoc iat ed w it h higher morbidit y and mort alit y (30%) t han w hen t he diagnosis is made and managed ac ut ely (71,425). T he diagnosis of diaphragmat ic rupt ure is usually suggest ed on t he basis of abnormalit ies on c hest radiography or is made inc ident ally at t he t ime of an explorat ory laparot omy (160). Diagnost ic or st rongly suggest iv e radiographic f indings inc lude t he presenc e of air- f illed v isc era (i.e., st omac h, bow el) and t he t ip of a nasogast ric t ube abov e t he diaphragm. T he nasogast ric t ube may be seen t o ext end inf eriorly below t he normal gast roesophageal junc t ion and t hen f orm an upw ard c urv e int o herniat ed gast ric f undus w it hin t he lef t hemit horax (340). Ot her abnormalit ies suggest iv e but not diagnost ic of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3076 diaphragmat ic injury are more c ommonly seen and inc lude an indist inc t or elev at ed hemidiaphragm, an irregular or lumpy diaphragm c ont our, a persist ent basilar opac it y t hat resembles at elec t asis or a supradiaphragmat ic mass, an unexplained pleural ef f usion, and f rac t ures of t he low er ribs (8,143,282). T he nonspec if ic it y of t hese f indings result s in t he c hest radiograph being inc onc lusiv e f or diaphragmat ic injury in most c ases. Diaphragmat ic rupt ure P.1438 w it h herniat ion of abdominal c ont ent s c an be mimic ked or masked by c onc urrent pulmonary abnormalit ies suc h as mult iple t raumat ic lung c y st s, low er lobe c ont usion and/or at elec t asis, pleural ef f usion, loc ulat ed hemopneumot horax, phrenic nerv e paresis, and t ot al or part ial ev ent rat ion of t he hemidiaphragm (143,295).

F igure 21- 26 Esophageal rupt ure. A: Comput ed t omography image on sof t t issue w indow demonst rat es a f luid- f illed esophagus (E) and periesophageal mediast inal air (ar r ow s) t rac king int o t he lef t pleural spac e. A small lef t pleural ef f usion is also present . B: Same image as (A) on lung w indow set t ing.

CT has been used t o diagnose diaphragmat ic rupt ure in pat ient s w it h nonspec if ic or equiv oc al c hest radiographs. On t ransv erse CT images, t he diaphragm appears as a t hin, c urv ilinear st ruc t ure of sof t t issue densit y out lined c ent rally by subdiaphragmat ic f at and peripherally by lung. T he post erolat eral port ions of t he diaphragm are usually best demonst rat ed, and t ears at t hose sit es are readily det ec t ed. T ears inv olv ing t he dome of t he diaphragm or port ions of t he diaphragm in c ont ac t w it h st ruc t ures of similar densit y , suc h as t he liv er, spleen, and st omac h, are more dif f ic ult t o det ec t , unless t here is assoc iat ed herniat ion of abdominal c ont ent s (173). CT has

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3077 been report ed t o hav e 61% t o 71% sensit iv it y and 87% t o 100% spec if ic it y in t he diagnosis of ac ut e t raumat ic diaphragmat ic rupt ure (219,310) CT f indings of diaphragmat ic rupt ure inc lude abrupt disc ont inuit y of t he diaphragm, herniat ion of abdominal v isc era or f at int o t he t horax, and f oc al w aist - like c onst ric t ion of t he st omac h or bow el at t he sit e of herniat ion (CT “ c ollar sign” ) (F ig. 21- 27) (219,310,391,487). A large gap bet w een t he t orn ends of t he diaphragm may be seen, giv ing rise t o t he “ absent diaphragm sign” (454). A diagnosis of herniat ion is indic at ed by t he presenc e of abdominal v isc era and/or f at post erolat eral (i.e., peripheral) t o t he diaphragm and t hus w it hin t he t horac ic c av it y . On oc c asion, CT c an demonst rat e diaphragmat ic disrupt ion bef ore v isc eral herniat ion, leading t o early surgic al int erv ent ion and av ert ing t he pot ent ially lif e- t hreat ening c omplic at ions of an undiagnosed herniat ion (179). Ot her CT f indings of diaphragmat ic rupt ure inc lude t hic kening of t he diaphragm as a result of edema or hemat oma (244) and herniat ed abdominal v isc era lay ering dependent ly in t he t horax against t he post erior ribs (“ dependent v isc era” sign) (F ig. 21- 28) (22). One series report ed t hat a posit iv e “ dependent v isc era” sign in w hic h t he upper one t hird of t he liv er abut t ed t he post erior right ribs or t he bow el or st omac h lay in c ont ac t w it h t he post erior lef t ribs w as ident if ied in 100% of pat ient s w it h lef t - sided diaphragmat ic rupt ure and 83% of pat ient s w it h right - sided diaphragmat ic rupt ure (22).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3078

F igure 21- 27 Diaphragmat ic rupt ure. A: Comput ed t omography (CT ) image at t he lev el of t he heart demonst rat es an air–c ont rast lev el w it hin st omac h (ST ), w hic h is herniat ed int o t he t horax. B, C : CT images more c audally demonst rat e t hic kened, disrupt ed lef t hemidiaphragm (st r aight ar r ow ) w it h herniat ed int raabdominal f at (c ur v ed ar r ow ) loc at ed lat eral t o t he diaphragm. (Case c ourt esy of Kev in Smit h, MD, Birmingham, Alabama.)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3079 F igure 21- 28 Diaphragmat ic rupt ure. A: Comput ed t omography image at t he lev el of t he heart (H) rev eals a debris- f illed st omac h (ST ) lay ing dependent ly in t he lef t hemit horax against t he post erior ribs (dependent v isc era sign). Not e assoc iat ed rib f rac t ure (ar r ow ). c , c olon. B: Coronal rec onst ruc t ion at t he lev el of t he desc ending aort a (DA) demonst rat es st omac h (ST ) and c olon (c ) w it hin t he lef t hemit horax.

P.1439 In pat ient s w it h subopt imal diaphragmat ic v isualizat ion or equiv oc al f indings of diaphragmat ic rupt ure, use of t hin- sec t ion helic al CT (e.g., 3 t o 5 mm) w it h ov erlapping rec onst ruc t ed images obt ained at 2- or 3- mm int erv als f or generat ion of sagit t al and c oronal ref ormat ions may help improv e diagnost ic ac c urac y (F ig. 21- 29) (391). In a ret rospec t iv e st udy t o det ermine t he sensit iv it y and spec if ic it y of helic al CT in diagnosing blunt diaphragmat ic injury , ref ormat t ed sagit t al and c oronal images helped det ec t subt le right sided v isc eral herniat ion and t o delineat e t he out line of t he diaphragm in 17 pat ient s w it h suspic ious c hest radiographic f indings but an int ac t diaphragm (391). T arget ed helic al CT of t he diaphragm w it h sagit t al and c oronal ref ormat t ed images has also been show n t o inc rease t he sensit iv it y of CT in t he det ec t ion of diaphragmat ic injury f rom 73% t o 92% in a prospec t iv e c ont rolled animal model (199). It is possible t hat use of MDCT sc anners w it h 1- t o 3- mm c ollimat ion and rapid mult iplanar ref ormat t ing w ill f urt her improv e t he diagnosis of blunt diaphragmat ic rupt ure, espec ially f or small def ec t s (312). In a small number of st able t rauma pat ient s, direc t c oronal and sagit t al MRI has also been perf ormed t o demonst rat e t raumat ic diaphragmat ic rupt ure (29,288,396). On T 1- w eight ed and gradient - ec ho MR sequenc es, t he normal diaphragm is seen as a c ont inuous hy point ense band, out lined by high- signalint ensit y f at on t he lef t and t he liv er on t he right . Injuries t o t he diaphragm appear on MRI as an abrupt def ec t in t he low - signal- int ensit y diaphragm. Int rat horac ic herniat ion of abdominal f at and/or v isc era P.1440 t hrough t he diaphragm rupt ure c an also be ac c urat ely demonst rat ed by MRI (197,396).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3080

F igure 21- 29 Diaphragmat ic rupt ure. A: A 5- mm helic al c omput ed t omography sec t ion demonst rat es herniat ion of a port ion of t he right lobe of t he liv er t hrough t he diaphragmat ic def ec t (ar r ow s). A small, inc ident al pulmonary nodule is not ed in t he right post erolat eral lung base. B: Coronal ref ormat ion demonst rat es herniat ed liv er in t he right low er c hest .

BLUNT ABDOMINAL TRAUMA Approximat ely 10% of all t rauma deat hs are a result of abdominal injuries (318,478). T rauma most of t en result s f rom t raf f ic ac c ident s, w it h f alls (mainly on t he w ork sit e), rec reat ional ac c ident s, and v iolenc e ac c ount ing f or t he ot her c auses (475). T w o dif f erent mec hanisms may c ause injury w it h blunt abdominal t rauma: c ompression f orc es and dec elerat ion f orc es. Compressiv e f orc es result f rom blow s or ext ernal c ompression against a f ixed objec t , suc h as t he spine. T hese f orc es c an c ause lac erat ions and subc apsular hemat omas of solid parenc hy mal organs suc h as t he spleen and liv er, or t hey c an def orm and inc rease t he int raluminal pressure in hollow organs suc h as t he bow el, result ing in rupt ure. Dec elerat ion injuries c ause st ret c hing and linear shearing f orc es bet w een f ixed and more f reely mov able objec t s, result ing in injuries t o st ruc t ures suc h as t he renal art eries and mesent eric blood v essels (318,466). T he pat ient 's c hanc e f or surv iv al inc reases t he earlier t rauma c are is inst it ut ed af t er t he injury ; t hus, t he c ommon goal of management of pat ient s w it h blunt abdominal t rauma is t he rapid ident if ic at ion of lif e- t hreat ening lesions and t heir c auses, and t he prompt init iat ion of appropriat e t reat ment (241,466). CT has bec ome inc reasingly v aluable and is ext ensiv ely used in t he early c linic al management of blunt abdominal t rauma (249,448). CT has prov ed t o be

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3081 a highly sensit iv e and spec if ic met hod f or t he det ec t ion of abdominal injury , and is t he met hod of c hoic e f or t he init ial ev aluat ion of pat ient s w it h hemody namic ally st able and unst able t rauma (92,342,344,478). T he ac c urac y of CT in t he diagnosis of blunt abdominal t rauma has been report ed t o be as high as 97% (92,319). Abdominal CT c an also help ev aluat e c oexist ing ext raabdominal injuries, suc h as pneumot horax, as w ell as pelv ic and spinal f rac t ures t hat may be c linic ally unsuspec t ed (474). T he more rec ent dev elopment of MDCT t ec hnology has f urt her enhanc ed t he role of CT in t he ev aluat ion of blunt abdominal t rauma. As in t horac ic t rauma, t he adv ant ages of MDCT in t he c ont ext of abdominal t rauma inc lude not only inc reased speed of image ac quisit ion and ov erall improv ed resolut ion but also t he abilit y t o obt ain mult iplanar rec onst ruc t ions and immediat e online int erpret at ion of images at t he w orkst at ion (344). MDCT allow s f or c omplet e sc anning in a single breat h- hold, and f ast er sc anning speeds and narrow c ollimat ion inc rease c ont rast opac if ic at ion in t he mesent eric , ret roperit oneal, and port al v essels, as w ell as in parenc hy mal organs. T his improv es ident if ic at ion of organ injury and, addit ionally , sit es of ac t iv e art erial bleeding. Breat h holding may not be possible in t rauma CT , and t he speed of mult islic e sc anning f urt her reduc es breat hing art if ac t (318,466,470). T he use of CT in t he init ial and f ollow - up ev aluat ions of t rauma v ic t ims has play ed a piv ot al role in dec reasing t he rat es of unnec essary explorat ory laparot omies and inc reasing c onserv at iv e nonoperat iv e management of abdominal injuries (9,59,355,379).

INDICATIONS In t he past , t he major indic at ion f or CT examinat ion of abdominal t rauma w as in pat ient s w it h suspec t ed abdominal injuries w ho w ere suf f ic ient ly hemody namic ally st able f or t ransport at ion f rom t he t rauma suit e t o t he CT sc anner (318,342,466). Addit ional indic at ions inc luded an equiv oc al phy sic al examinat ion, assoc iat ed head injury or int oxic at ion, assoc iat ed spinal c ord injury , hemat oma w it h a signif ic ant mec hanism of injury , dec reasing hemat oc rit , elev at ed amy lase, or assoc iat ed pelv ic f rac t ure (113,338). Rec ent ly , CT has been inc reasingly used in pat ient s w it h suspec t ed ac t iv e int ernal bleeding, and is now a rec ognized met hod f or ev aluat ion and dec ision making in pat ient s w it h hemody namic ally unst able t rauma, prov ided t hat it is av ailable w it hout delay and t hat lif e- support measures are not int errupt ed during examinat ion (342).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3082 Bef ore t he w idespread use of CT , diagnost ic perit oneal lav age (DPL) w as t he gold st andard f or t he det ec t ion of hemoperit oneum (266). More rec ent ly , DPL has been reserv ed f or hemody namic ally unst able pat ient s w ho may require immediat e surgery (478). While DPL is v ery sensit iv e f or det ec t ing hemorrhage, is quic k and simple t o perf orm, and does not require sophist ic at ed equipment , it has sev eral import ant limit at ions. It c annot dif f erent iat e inc onsequent ial f rom signif ic ant bleeding, w hic h may result in unnec essary laparot omies. DPL does not prov ide inf ormat ion on loc at ion or ext ent of injuries and it of t en f ails t o det ec t bleeding in t he ret roperit oneum. It is an inv asiv e proc edure, and t raumat ic c annula insert ion c an result in f alse–posit iv e examinat ions (113,153,478). F ut hermore, ret ained lav age f luid may simulat e int raperit oneal blood on subsequent CT examinat ion. T he adv ant ages of CT ov er DPL inc lude it s high sensit iv it y and spec if ic it y f or v isc eral lac erat ions, it s noninv asiv e nat ure, t he c apabilit y t o loc alize t he sourc e of hemoperit oneum, and t he abilit y t o assess bot h int raperit oneal and ret roperit oneal injuries (113). DPL has f allen int o disf av or w it h many t rauma surgeons bec ause abdominal injuries t hat c an be managed nonoperat iv ely f ollow ing CT examinat ion w ould require operat iv e int erv ent ion based on c urrent ly ac c ept ed guidelines f or DPL (153). CT examinat ion of t he abdomen f or t rauma has largely replac ed ot her imaging t ec hniques, suc h as radionuc lide sc int igraphy , angiography , and ult rasound (US) (153). T he bedside f our- quadrant abdominal US examinat ion f or t rauma has been ref erred t o as f oc used abdominal sonogram f or t rauma (F AST ) (280,318). F AST is a noninv asiv e met hod P.1441 f or t he ident if ic at ion of blunt abdominal t rauma and is similar t o DPL in t hat it s purpose is t o ident if y hemoperit oneum (153,280). Many t rauma c ent ers hav e inc orporat ed t he use of F AST f or t he ev aluat ion of blunt abdominal t rauma (3,280,466). It w as originally suggest ed t hat t he rout ine use of F AST c ould result in a reduc t ion in t he number of abdominal CT sc ans, and t heref ore a reduc t ion in t he c ost of t reat ment of blunt abdominal t rauma (368). How ev er, as w it h DPL, F AST does not ident if y t he sourc e of t he bleeding, ev aluat e t he ret roperit oneum, or det ec t hollow organ injuries or oc c ult f rac t ures. F AST also has t he disadv ant age of being operat or dependent , and t he qualit y of t he examinat ion c an be af f ec t ed by obesit y , ileus, and subc ut aneous emphy sema. F urt hermore, t he absenc e of hemoperit oneum does not exc lude t he presenc e

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3083 of organ injuries. Bec ause of t hese limit at ions, CT is f elt t o be superior t o US as t he init ial sc reening examinat ion f or blunt abdominal t rauma (280,466).

TECHNIQUE Proper pat ient preparat ion and sc anning t ec hnique is c rit ic al f or ac c urat e abdominal CT examinat ion in pat ient s w it h blunt abdominal t rauma. Ext raneous objec t s suc h as ECG leads, IV lines, and ot her monit oring or support apparat us should be reposit ioned out of t he sc anning f ield w henev er possible bec ause t he st reak art if ac t s t hey produc e degrade image qualit y and may simulat e or obsc ure t raumat ic lesions (113). T he pat ient 's arms should be plac ed ov er t he c hest or abov e t he head. If t his c annot be done, t hen t he arms should be posit ioned next t o t he t runk bec ause allow ing an air gap t o remain bet w een t he arm and t he body c auses w orse art if ac t t han sec uring t he limb against t he abdomen (140). If t he arms must remain ov er t he abdomen, a larger sc anning f ield of v iew may be used t o dec rease art if ac t (114). Rest raint s or sedat ion may be nec essary t o av oid mot ion art if ac t s in pat ient s unable t o maint ain proper posit ion. T he rout ine use of oral c ont rast mat erial in CT examinat ion of abdominal t rauma is c ont rov ersial. In some t rauma c ent ers, dilut e (1% t o 2%), w at ersoluble c ont rast mat erial is administ ered orally or v ia a nasogast ric t ube prior t o CT sc anning, w hile in ot hers, it is not a part of t he t rauma prot oc ol. Oral c ont rast mat erial c an aid in t he ident if ic at ion of bow el loops, delineat ion of t he mesent ery , and dif f erent iat ion of bow el f rom hemat oma, hemorrhage, and panc reat ic injury . Disadv ant ages of oral c ont rast mat erial inc lude risk of aspirat ion, v omit ing, and addit ional t ime requirement s f or it s dispersal, w hic h may delay diagnosis and t reat ment of injuries. Sev eral rec ent st udies suggest t hat oral c ont rast mat erial is unnec essary , as no diagnoses w ere missed in it s absenc e (84,402,420). As t ime is one of t he most import ant f ac t ors in t he early management of t rauma v ic t ims, many of w hom hav e injuries inv olv ing mult iple organ sy st ems, t he delay needed f or t he dispersal of oral c ont rast mat erial may not be just if ied, espec ially if t here is no signif ic ant added benef it . Post t raumat ic abdominal CT examinat ions should be perf ormed using IV c ont rast mat erial, unless c ont raindic at ed by know n major c ont rast allergy or sev ere renal insuf f ic ienc y . IV inf usion of c ont rast mat erial maximizes t he dif f erenc e bet w een c ont rast - enhanc ing parenc hy ma and nonenhanc ing hemat omas and lac erat ions (113). It also aids in det ec t ion of ext rav asat ion of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3084 c ont rast - opac if ied urine (113) and in v isualizat ion of sit es of ac t iv e art erial hemorrhage (202,395). IV c ont rast mat erial is best administ ered w it h an aut omat ed pow er injec t or v ia a large- bore peripheral v enous line or c ent ral v enous c at het er. A t ot al of approximat ely 120 t o 180 mL of 60% c ont rast mat erial c an be giv en IV at a rat e of 2 t o 4 mL per sec ond (318,403,470). Sc anning is usually init iat ed 70 t o 90 sec onds af t er t he st art of c ont rast inf usion (403,466). T he t iming of t he sc an af t er t he c ont rast injec t ion is import ant , sinc e early sc anning c an produc e art if ac t s t hat may simulat e injury , espec ially in t he spleen and kidney s, and lat e sc anning c an dec rease sensit iv it y t o injuries t hat may be present . Wit h t he inc reasing use of MDCT and f ast er ac quisit ions, t he t iming of c ont rast mat erial deliv ery bec omes ev en more c rit ic al. In general, short er ac quisit ion t imes may reduc e t he t ot al amount of c ont rast mat erial needed, but at t he same t ime may require higher injec t ion rat es (129). Sc anning should span f rom t he dome of t he diaphragm t o t he inf erior aspec t of t he isc hium. Wit h SDCT , sc anning is generally perf ormed w it h 5- t o 8- mmt hic k sec t ions and a pit c h of 1 t o 2. T ec hnic al f ac t ors w it h MDCT v ary w it h t he number of det ec t ors. In MDCT , t he t hic kness of t he x- ray beam is det ermined by t he det ec t or row c ollimat ion, as opposed t o t he x- ray beam c ollimat ion, so t he def init ion of pit c h is ext ended. F or example, a 4- slic e CT sc an using 5- mm row c ollimat ion (and t heref ore 20- mm x- ray beam c ollimat ion) and a 15- mm t able t ranslat ing dist anc e per rot at ion w ill result in a helic al pit c h of 3 (i.e., 15/5) rat her t han 0.75 (i.e., 15/20) (190). MDCT of f ers unparalleled speed of ac quisit ion, spat ial resolut ion, and anat omic c ov erage. How ev er, it also brings w it h it t he c hallenge of assessing a signif ic ant inc rease in number of rapidly generat ed, rec onst ruc t ed c ross sec t ions. Addit ional t ec hniques av ailable on c linic al w orkst at ions inc lude mult iplanar ref ormat ion, maximum int ensit y projec t ion, shaded surf ac e display , and v olume rendering (371). Pat ient s should be c losely monit ored t hroughout t he examinat ion, and adequat e equipment and personnel f or emergenc y resusc it at ion should be readily av ailable (475,478). Ideally , t he CT sc anning area should be loc at ed as near as possible t o t he t rauma room t o allow rapid t ransport t o and f rom t he sc anner. Whet her v iew ed on f ilm or on t he c onsole v ideo monit or, all images should be rev iew ed w it h mult iple w indow set t ings (lung, bone, and st andard sof t t issue) t o det ec t not only organ injury but also pneumot horax, pneumoperit oneum, and bone injury (403).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3085 P.1442

HEMOPERITONEUM Hemoperit oneum is a c ommon result of blunt abdominal t rauma, and it s ident if ic at ion on CT should prompt a t horough searc h f or injury t o v isc eral organs (19,325,403, 466,478). At t imes, small quant it ies of hemoperit oneum may be t he only sign of subt le or oc c ult v isc eral injury , part ic ularly t hose inv olv ing t he bow el or mesent ery . CT is highly sensit iv e and spec if ic f or diagnosing hemoperit oneum (121), w hic h init ially t ends t o c ollec t near t he sourc e of bleeding and t hen spills ov er int o more dependent port ions of t he perit oneal c av it y . Morison's pouc h (also know n as t he hepat orenal f ossa or post erior subhepat ic spac e), t he most dependent perit oneal rec ess in t he upper abdomen, is t he most c ommon sit e of blood c ollec t ion seen on CT in upper abdominal t rauma (F ig. 21- 30) (113). Ot her c ommon sit es of blood ac c umulat ion inc lude t he perihepat ic (right subphrenic ) and perisplenic (lef t subphrenic ) spac es, t he parac olic gut t ers (perit oneal rec esses lat eral t o t he asc ending and desc ending c olon) (F ig. 21- 31), and t he pelv is, part ic ularly adjac ent t o t he urinary bladder. Blood f rom any int raabdominal sourc e t y pic ally f low s dow n along t he root of t he mesent ery and t he right parac olic gut t er int o t he pelv is (278). Wit h ext ensiv e hemorrhage, large c ollec t ions of blood may f ill t he pelv is, ev en w hen relat iv ely lit t le blood is seen in t he parac olic gut t ers or ot her upper abdominal sit es (121) (F ig. 21- 32); t his is bec ause t he pelv is is t he most dependent port ion of t he perit oneal c av it y and c ont ains up t o one t hird of it s v olume. It is import ant , t heref ore, t hat t he ent ire pelv is be sc anned in pat ient s f ollow ing blunt abdominal t rauma t o ac c urat ely assess t he presenc e and ext ent of hemoperit oneum (113).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3086

F igure 21- 30 Hemoperit oneum. Blood is present in Morison's pouc h (ast er isk), t he most dependent perit oneal rec ess in t he upper abdomen. Not e t hat t he ac ut e hemoperit oneum appears relat iv ely low in at t enuat ion c ompared w it h t he at t enuat ion of enhanc ed liv er and renal parenc hy ma.

F igure 21- 31 Hemoperit oneum. Comput ed t omography image demonst rat es blood t rac king along bot h parac olic gut t ers (ar r ow s) in t his pat ient f ollow ing blunt abdominal t rauma. A small lef t perinephric hemat oma (ar r ow head) is also present .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3087

F igure 21- 32 Hemoperit oneum sec ondary t o splenic lac erat ion. Comput ed t omography (CT ) image t hrough t he low er pelv is demonst rat es a large amount of blood pooling in t he pelv is. If CT sec t ions t hrough t he pelv is had not been obt ained, t he ext ent of hemoperit oneum w ould hav e been grossly underest imat ed. U, ut erus; R, rec t um; B, urinary bladder.

T he CT appearanc e of blood in t he perit oneal c av it y is v ariable and depends on t he loc at ion, age, and phy sic al st at e (c lot t ed v ersus ly sed) of ext rav asat ed blood. Immediat ely af t er hemorrhage, int raperit oneal blood has t he same at t enuat ion as c irc ulat ing blood, but w it hin hours, it s at t enuat ion inc reases as hemoglobin is c onc ent rat ed during c lot f ormat ion (315,317). Clot t ed blood usually measures bet w een 50 and 75 HU at t enuat ion, w hereas ly sed blood f low ing f reely w it hin t he perit oneal c av it y has at t enuat ion v alues generally ranging f rom 30 t o 45 HU. Densely c lot t ed blood may hav e at t enuat ion v alues of great er t han 100 HU (114). Clot s w it hin t he perit oneal c av it y t end t o ly se rapidly bec ause of repet it iv e respirat ory mot ion and adjac ent bow el perist alsis, w hereas c lot s w it hin solid v isc era, suc h as t he liv er, remain int ac t f or longer periods (121). In most c ases, t he at t enuat ion v alue of blood begins t o dec rease w it hin sev eral day s as P.1443 c lot ly sis t akes plac e. T he at t enuat ion v alue c ont inues t o dec rease st eadily w it h t ime and of t en approac hes t hat of w at er (0 t o 20 HU) af t er 2 t o 3 w eeks (229). Rec ent int raperit oneal hemorrhage c an exhibit a v ariet y of morphologic f eat ures. T he f luid c ollec t ion may be homogeneously hy perdense or it may be inhomogeneous, w it h linear or nodular areas of high at t enuat ion int ermixed w it h low er at t enuat ion f luid. T he inhomogeneit y may result f rom irregular c lot

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3088 resorpt ion or int ermit t ent bleeding, leading t o repeat ed episodes of c lot f ormat ion and ret rac t ion (481). Oc c asionally , f resh blood w it hin a hemat oma or c onf ined w it hin a perit oneal spac e may demonst rat e a hemat oc rit ef f ec t , w it h lay ering of serous f luid on dependent , sediment ed ery t hroc y t es and c lot (121) (F ig. 21- 33). More f requent ly , a loc alized c ollec t ion of high- at t enuat ion c lot t ed blood, ref erred t o as t he sent inel c lot , is seen in c lose proximit y t o a sit e of v isc eral injury (325) (F ig. 21- 34). T he sent inel c lot is a sensit iv e sign of v isc eral injury , and it may be t he only sign indic at ing t he sourc e of perit oneal hemorrhage in a signif ic ant perc ent age of c ases. When present , it should prompt c aref ul examinat ion of t he adjac ent v isc era f or subt le or oc c ult injury . In some pat ient s, espec ially t hose w it h small c apsular lac erat ions, t he loc alized periv isc eral hemat oma may be more ev ident t han t he underly ing int raparenc hy mal hemat oma or lac erat ion (121). As suc h, t he sent inel c lot sign has been not ed t o be part ic ularly usef ul in t he diagnosis of subt le bow el, mesent eric , and splenic injuries (140,325). It must be remembered t hat t he presenc e of hemoperit oneum on CT does not nec essarily indic at e t hat ac t iv e hemorrhage is present . Rat her, t he quant it y of hemoperit oneum on a single CT st udy merely ref lec t s t he amount of blood lost sinc e t he t ime of injury . Serial CT ev aluat ion of hemoperit oneum may be usef ul in doc ument ing resolut ion or in det ec t ing new hemorrhage (131). Hemoperit oneum should resolv e signif ic ant ly in most c ases by 1 w eek af t er injury . Persist enc e of hemoperit oneum w it hout c hange f or 3 t o 7 day s af t er injury suggest s c ont inued int raperit oneal bleeding, ev en t hough t he pat ient may remain hemody namic ally st able (131).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3089

F igure 21- 33 Hemoperit oneum w it h hemat oc rit ef f ec t . Comput ed t omography sc an t hrough t he low er pelv is demonst rat es a large amount of blood f illing t he pelv is. Not e hemat oc rit ef f ec t w it h blood element s lay ering dependent ly (ar r ow s). UT , ut erus.

Ac t iv e art erial hemorrhage c an be ident if ied on c ont rast - enhanc ed CT as f oc al or dif f use high- at t enuat ion areas of ext rav asat ed c ont rast - enhanc ed blood (F ig. 21- 35) (202,395). T he areas of ext rav asat ion range in at t enuat ion f rom 80 t o 370 HU (higher at t enuat ion t han f ree or c lot t ed blood) and t y pic ally are isodense or hy perdense t o t he abdominal aort a and adjac ent major art eries. T he areas of ext rav asat ion are of t en surrounded by a large hemat oma t hat is low er in at t enuat ion t han t he ext rav asat ed c ont rast mat erial. Wit h t he inc reasing use of MDCT , det ec t ion of ac t iv e bleeding sit es in pat ient s w it h blunt abdominal t rauma is bec oming inc reasingly more c ommon. T he f ast er dat a ac quisit ion and higher spat ial resolut ion af f orded by MDCT enable v isualizat ion of ac t iv e hemorrhage as a f oc al jet of ext rav asat ed c ont rast mat erial, or as a f oc al or dif f use c ollec t ion of high- at t enuat ion ext rav asat ed c ont rast mat erial surrounded by low - at t enuat ion hemat oma. In pat ient s w it h signif ic ant blood loss result ing in hy pov olemia, sev eral CT signs may be seen. T hese inc lude a small, c onst ric t ed aort a (399), a f lat t ened or c ollapsed

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3090 inf erior v ena c av a (203), and abnormally int ense c ont rast enhanc ement of t he bow el w all and kidney s (411).

F igure 21- 34 Splenic lac erat ions w it h hemoperit oneum and sent inel c lot . Cont rast - enhanc ed c omput ed t omography image demonst rat es mult iple splenic lac erat ions and high- at t enuat ion c lot t ed perisplenic blood, or so- c alled sent inel c lot . Low er- at t enuat ion ly sed blood is also present in t he perihepat ic spac e.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3091

F igure 21- 35 Ac t iv e art erial hemorrhage. Cont rast - enhanc ed mult idet ec t or c omput ed t omography image demonst rat es a linear f oc us of ext rav asat ed c ont rast - enhanc ed blood (ar r ow ) originat ing f rom t he spleen. T his f oc us of ac t iv e hemorrhage is surrounded by a large perisplenic hemat oma (h) t hat is low er in at t enuat ion t han t he ext rav asat ed c ont rast - enhanc ed blood. Perihepat ic blood (ar r ow head) is also ev ident .

P.1444

SPECIFIC TRAUMA SITES Spleen In blunt abdominal t rauma, t he spleen is t he most f requent ly af f ec t ed organ, ac c ount ing f or approximat ely 40% of abdominal organ injuries (19,318,344,403,466,478). T raumat ic injuries t o t he spleen must alw ay s be c onsidered in pat ient s w ho hav e suf f ered blow s t o t he lef t low er c hest or lef t upper abdomen, w het her f rom mot or v ehic le ac c ident s, sport s ac c ident s, f alls, or nonac c ident al t rauma. T he presenc e of lef t low er rib f rac t ures is highly suggest iv e of t he simult aneous presenc e of splenic injury (19,403,466). Cont rast - enhanc ed CT is t he modalit y of c hoic e f or ev aluat ion of splenic t rauma and has been report ed t o be up t o 98% sensit iv e f or det ec t ing blunt splenic injury (318,344,403). F ollow ing rapid IV injec t ion of c ont rast mat erial,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3092 t he spleen may init ially exhibit a het erogeneous pat t ern of parenc hy mal opac if ic at ion, ref lec t ing v ariable blood f low w it hin dif f erent c ompart ment s of t he spleen (145) (F ig. 21- 36). Care must be t aken not t o misint erpret t his early post injec t ion het erogeneit y as represent ing splenic injury . In quest ionable c ases, repeat sc ans should be obt ained f ollow ing equilibrat ion of t he c ont rast mat erial. In normal c ases, t he splenic parenc hy ma ac hiev es a unif orm, homogeneous appearanc e w it h no surrounding hemorrhage. Injury t o t he spleen c an t ake t he f orm of lac erat ion, int rasplenic hemat oma, subc apsular hemat oma, or inf arc t ion (344,466). Splenic lac erat ion t y pic ally appears as an irregular linear area of hy podensit y on c ont rast - enhanc ed CT (F ig. 21- 37). Int rasplenic hemat oma appears as a broader area of hy podense, nonperf used splenic parenc hy ma (F ig. 21- 38). T he int raparenc hy mal hemat oma may be homogeneous or inhomogeneous, and may c ont ain a higher at t enuat ion c lot (19,318,403,478). Subc apsular hemat omas appear as c resc ent ic or ov al c ollec t ions of f luid t hat f lat t en or indent t he underly ing splenic parenc hy ma (113,318, 478) (F ig. 21- 39). Splenic inf arc t s may oc c ur f ollow ing injury t o t he splenic v asc ulat ure and appear as w edge- shaped areas of nonperf usion t hat ext end t o t he splenic c apsule. Unenhanc ing port ions of t he spleen should suggest injury or t hrombosis of t he art ery of t he af f ec t ed segment (478), alt hough perf usion def ec t s may also be a result of c ont usion or may c orrespond t o rev ersible loc al reac t iv e hy poperf usion sec ondary t o hy pot ension (19). In c ases of sev ere t rauma, t he spleen may be shat t ered int o mult iple small f ragment s. Mult iple lac erat ions P.1445 c onnec t ing opposed v isc eral surf ac es def ines a shat t ered spleen (318,403,466,478).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3093 F igure 21- 36 Het erogeneous early splenic enhanc ement . A: Early art erial phase c ont rast - enhanc ed c omput ed t omography image demonst rat es het erogeneous enhanc ement of t he splenic parenc hy ma t hat c ould be mist aken f or splenic injury . Not e t he absenc e of perisplenic hemat oma. B: Delay ed sc an during equilibrium phase demonst rat es homogeneous splenic parenc hy ma w it hout ev idenc e of splenic injury .

F igure 21- 37 Splenic lac erat ion. Cont rast - enhanc ed c omput ed t omography sc an demonst rat es irregular, low - at t enuat ion splenic lac erat ion ext ending t o t he splenic hilum. T here is a small amount of perisplenic blood and an ac t iv e ext rav asat ion sit e (ar r ow ).

St reak art if ac t f rom nasogast ric t ubes or ECG leads may mimic splenic lac erat ion, and ideally t hese objec t s should be reposit ioned or remov ed prior t o sc anning. Beam- hardening art if ac t f rom ribs and st reak art if ac t f rom an air–c ont rast int erf ac e in t he st omac h may also simulat e splenic injury . Suc h art if ac t s generally are bet t er def ined and more regular in appearanc e t han t rue lac erat ions, and of t en ext end bey ond t he margin of t he spleen. Splenic c lef t s, most c ommonly loc at ed in t he superomedial aspec t of t he spleen, c an mimic lac erat ion but t y pic ally are more smoot hly c ont oured in appearanc e (F ig. 21- 40). T he absenc e of assoc iat ed perisplenic blood is also helpf ul in dist inguishing c lef t s f rom t rue lac erat ions (113). Enhanc ing at elec t at ic lung, as w ell as a prominent lef t lobe of t he liv er draping around t he spleen, may on oc c asion simulat e splenic injury and perisplenic hemat oma (55).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3094

F igure 21- 38 Splenic hemat oma and hemoperit oneum. Cont rast - enhanc ed c omput ed t omography sc an demonst rat es a broad area of hy podense, nonperf used splenic parenc hy ma represent ing int rasplenic hemat oma (H). Low er at t enuat ion perisplenic blood (t hic k ar r ow s) is present . T he pat ient also has a lef t hemopneumot horax (t hin ar r ow s) and subc ut aneous emphy sema. ST , st omac h.

F igure 21- 39 Subc apsular splenic hemat oma. Cont rast - enhanc ed c omput ed t omography image demonst rat es a lent ic ular- shaped subc apsular hemat oma (H) t hat indent s t he underly ing splenic parenc hy ma. A higher at t enuat ion perisplenic hemat oma (ar r ow ) is seen post eriorly . P, panc reat ic t ail; K, lef t kidney .

Hemoperit oneum is present in nearly all pat ient s w it h c linic ally import ant splenic injury . In c ases in w hic h t here is signif ic ant int raabdominal f luid, t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3095 presenc e of loc al perisplenic c lot , t he so- c alled sent inel c lot , suggest s splenic injury as t he sit e of bleeding (F igs. 21- 34, 21- 38, and 21- 41) (325). Suc h a c lot usually appears denser and more het erogeneous t han t he remainder of t he int raabdominal blood (120). T he sent inel c lot is a v aluable adjunc t in t he CT ev aluat ion of splenic t rauma, being bot h sensit iv e and spec if ic f or ident if ic at ion of t he injured organ. While CT demonst rat es t he parenc hy mal injury it self in a large perc ent age of c ases, t here are a signif ic ant number of c ases in w hic h perisplenic c lot is t he princ ipal f inding indic at ing t he spleen as t he sourc e of t he hemoperit oneum. In a smaller perc ent age of c ases, t he sent inel c lot may be t he only c lue t o t he sourc e of t he hemorrhage (120,325). Ac t iv e bleeding c an be ident if ied on c ont rast - enhanc ed CT as int ra- or ext rasplenic areas of bright v asc ular enhanc ement w it h an at t enuat ion similar t o or great er t han t hat of t he aort a or an adjac ent major art ery (F ig. 21- 35 and 21- 42). T he appearanc e may v ary w it h t he rat e of hemorrhage and t he CT t ec hnique used. Wit h t he int roduc t ion of f ast er MDCT prot oc ols, earlier dat a ac quisit ion may allow smaller amount s of ac t iv e hemorrhage t o be det ec t ed bef ore t he high- densit y c ont rast mat erial is dilut ed by surrounding hemat oma, espec ially in a perisplenic loc at ion (246,325). Pseudoaneury sm f ormat ion c an oc c ur f ollow ing t rauma and appears as a f oc al w ell- c irc umsc ribed area of v asc ular enhanc ement w it hin t he splenic parenc hy ma t hat is larger t han t he normal v essels (F ig. 21- 43). Surrounding hemat oma is f requent ly not ed (139,178). T he CT at t enuat ion of a pseudoaneury sm may be af f ec t ed by sev eral mec hanisms. Higher rat es of IV c ont rast mat erial injec t ion w ill raise c ont rast P.1446 media lev els and t heref ore t he at t enuat ion of t he abnormalit y . Poor c ardiac out put , v asodilat at ion, and hy pot ension may dec rease perf usion, result ing in dec reased at t enuat ion of t he pseudoaneury sm (246).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3096

F igure 21- 40 Congenit al splenic c lef t s. A: Comput ed t omography image demonst rat es a sharply marginat ed c lef t in t he post erior t ip of t he spleen. T he smoot h, rounded c ont our of t he c lef t as it meet s t he margin of t he spleen, as w ell as t he absenc e of perisplenic hemat oma, is helpf ul in dist inguishing a c ongenit al c lef t f rom a parenc hy mal lac erat ion. B: Anot her pat ient w it h mult iple splenic c lef t s along t he lat eral margin of t he spleen.

CT f indings t hat indic at e ongoing hemorrhage and t he possible need f or more immediat e angiographic int erv ent ion or surgery inc lude ac t iv e c ont rast mat erial ext rav asat ion, seen as a f oc al jet or “ c ont rast blush,” a pseudoaneury sm, or an art eriov enous f ist ula (325,470). Alt hough some post t raumat ic v asc ular lesions, part ic ularly t hose of small size, may t hrombose

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3097 spont aneously , many t rauma surgeons f eel t hat t he presenc e of a c ont rast blush or a pseudoaneury sm should aut omat ic ally prompt eit her operat iv e or angiographic int erv ent ion. Ident if ic at ion of a c ont rast blush on c ont rast enhanc ed CT may be predic t iv e of f ailure of nonoperat iv e c onserv at iv e management . At t he least , c lose medic al observ at ion is required should int erv ent ion be def erred (92,118,139,324,385,394). Major c hanges hav e oc c urred in t he past t w o t o t hree dec ades in t he t reat ment of t raumat ic injuries t o t he spleen, w it h a c ont inuing t rend aw ay f rom immediat e splenec t omy and t ow ard c onserv at iv e t herapy (374,452). Splenec t omy P.1447 c an permanent ly inc rease susc ept ibilit y t o inf ec t ions, t he most dev ast at ing of w hic h is ov erw helming post splenec t omy sepsis, a rare c omplic at ion c harac t erized by f ulminant and of t en f at al bac t erial inf ec t ion (355,374,427,434,452).

F igure 21- 41 Splenic f rac t ure w it h hemoperit oneum and perisplenic sent inel c lot . Comput ed t omography image at t he lev el of t he splenic v ein (SV) demonst rat es an irregular splenic f rac t ure (ar r ow ) and adjac ent highat t enuat ion sent inel c lot (d). Not e low er at t enuat ion ly sed blood (h) around t he liv er.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3098

F igure 21- 42 Part ial t ransec t ion of t he splenic hilum w it h ac t iv e bleeding and massiv e hemoperit oneum. A, B: Comput ed t omography (CT ) sc ans t hrough t he upper pole of t he right kidney demonst rat e a large amount of hemoperit oneum, v irt ually absent perf usion of t he splenic parenc hy ma, and ac t iv e bleeding (ar r ow s) f rom disrupt ed hilar v essels. C : CT sc an t hrough t he low er margin of t he spleen (S) show s some preserv at ion of splenic enhanc ement c onsist ent w it h part ial hilar t ransec t ion. A small lac erat ion is not ed in t he lef t kidney . (Case c ourt esy of Christ ine O Menias, M.D., St . Louis, Missouri.)

At t empt s hav e been made by sev eral inv est igat ors t o grade t he CT appearanc e of splenic injuries t o ident if y t hose pat ient s w ho c an be t reat ed suc c essf ully nonoperat iv ely . T he desirabilit y of suc h a predic t iv e grading sy st em is inc reased by t he f ac t t hat early surgic al int erv ent ion more of t en result s in splenic salv age t han does delay ed operat ion (355,379, 450). Most CT grading sy st ems assess t he int egrit y of t he splenic c apsule, t he size of hemat oma, t he lengt h and number of lac erat ions, inv olv ement of segment al or hilar v essels, and ext ent of parenc hy mal dev asc ularizat ion (41,118,301,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3099 318,394). T w o of t he more w ell- know n c lassif ic at ion sy st ems inc lude t hose by Bunt ain et al. (T able 21- 1) (41) and P.1448 t he Americ an Assoc iat ion f or t he Surgery of T rauma (AAST ) (T able 21- 2) (394).

F igure 21- 43 Splenic pseudoaneury sm (t hic k ar r ow ) in a 22- y ear- old man inv olv ed in a mot or v ehic le ac c ident . Blood is present in t he perisplenic spac e and Morison's pouc h (ast er isk). T hin ar r ow s point t o a lef t pneumot horax and c hest w all emphy sema.

Early report s suggest ed t hat t he use of t hese grading sy st ems w ould be usef ul in predic t ing w hic h pat ient s w ould benef it f rom nonoperat iv e management v ersus urgent surgic al int erv ent ion, w it h t he need f or surgery indic at ed by t he sc ore of t he giv en sy st em. T hese sy st ems hav e met w it h only v ariable suc c ess. Y oung pat ient s under 20 y ears of age may do w ell w it h ev en sev ere degrees of injury , w hereas pat ient s ov er 55 y ears of age may require surgery f or t he low est grades of injury (318,355,379,416). Sev eral more rec ent st udies hav e show n t hat w hile CT is highly ac c urat e in delineat ing t he ext ent of splenic injury , t his det erminat ion c annot reliably predic t t he suc c ess or f ailure of nonsurgic al management of blunt splenic t rauma. Regardless of w hic h paramet ers are used in t he grading sy st ems, a small, but signif ic ant , number of pat ient s w it h low sc ores or ev en a negat iv e CT experienc e nonsurgic al f ailure or delay ed splenic rupt ure. Clinic al signs in t hese pat ient s inc lude f alling hemat oc rit , sudden inc rease in pain, and hy pot ension. F urt hermore, higher grades of splenic injury are not nec essarily assoc iat ed w it h an inc reased risk of nonoperat iv e f ailure (228,297,450). Most rec ent inv est igat ors

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3100 agree t hat , w hile CT is v aluable f or init ial doc ument at ion, and somet imes f or monit oring t he progression, of splenic injuries, t he dec ision f or surgery should be based princ ipally on hemody namic v ariables, laborat ory st udies, and serial bedside c linic al assessment s (9,228,297,374,434,450). TABLE 21- 1 BUNTAIN C LASSIF IC ATION OF SPLENIC INJURY Class I

Loc alized c apsular disrupt ion or subc apsular hemat oma, w it hout signif ic ant parenc hy mal injury . Single or mult iple c apsular and parenc hy mal disrupt ions, ransv erse or longit udinal, t hat do not ext end int o t he hilum or inv olv e major v essels. Int raparenc hy mal hemat oma may or may not c oexist . Deep f rac t ures, single or mult iple, t ransv erse or longit udinal, ext ending int o t he hilum and inv olv ing major blood v essels. Complet ely shat t ered or f ragment ed spleen, or separat ed f rom it s normal blood supply at t he pedic le.

Class II

Class III

Class IV

A. Wit hout ot her int raabdominal injury . B. Wit h ot her assoc iat ed int raabdominal injury . B1. solid v isc us B2. hollow v isc us C. Wit h assoc iat ed ext raabdominal injury . Adapt ed f rom Bunt ain WL, Gould HR, Maull KI. Predic t abilit y of splenic salv age by c omput ed t omography . J T r aum a 1988;28:24–34. TABLE 21- 2 AMERIC AN ASSOC IATION F OR THE SURGERY OF TRAUMA SPLENIC INJURY SC ALE (1994 REVISION) Gra de a

Ty pe

I

Hemat oma Lac erat ion

II

Hemat oma Lac erat ion

III

Hemat oma Lac erat ion

Computed Body Tomography with MRI Correlation , 4th Edition

De sc ription of injury Subc apsular, less t han 10% surf ac e area. Capsular t ear, less t han 1 c m parenc hy mal dept h. Subc apsular, 10% t o 50% surf ac e area; int raparenc hy mal, less t han 5 c m in diamet er. 1 t o 3 c m parenc hy mal dept h; does not inv olv e a t rabec ular v essel. Subc apsular, great er t han 50% surf ac e area or expanding; rupt ured subc apsular or parenc hy mal hemat oma.

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3101

IV

Lac erat ion

V

Lac erat ion Vasc ular

Great er t han 3 c m parenc hy mal dept h or inv olv ed t rabec ular v essels. Lac erat ion inv olv ing segment al or hilar v essels and produc ing major dev asc ularizat ion (great er t han 25% of spleen). Complet ely shat t ered spleen. Hilar v asc ular injury t hat dev asc ularizes spleen

a Adv anc e one grade f or mult iple injuries up t o grade III.

F rom Shanmuganat han K, Mirv is SE, Boy d- Kranis R, et al. Nonsurgic al management of blunt splenic injury : use of CT c rit eria t o selec t pat ient s f or splenic art eriography and pot ent ial endov asc ular t herapy . Radiology 2000;217:75–82, w it h permission. Delay ed splenic rupt ure is a rare but w ell- rec ognized and pot ent ially

dangerous c linic al ent it y t hat has been report ed in pat ient s in w hom t he init ial CT sc an show ed no ev idenc e of splenic abnormalit y (333,450). No exac t dat a exist regarding it s t rue inc idenc e. Delay ed rupt ure may be sec ondary t o splenic f rac t ure in w hic h t here is lit t le init ial hemorrhage or in w hic h poor c ont rast opac if ic at ion P.1449 of t he spleen renders hemat oma isodense w it h splenic parenc hy ma (333,450). Sev eral mec hanisms hav e been proposed, inc luding delay ed rupt ure of a subc apsular hemat oma as a result of inc reased osmot ic pressure dev eloping in t he c ourse of c lot ly sis and f ree rupt ure of an init ially c onf ined perisplenic hemat oma int o t he perit oneal c av it y (19,478). Splenic injuries may t ake sev eral mont hs t o almost a y ear t o f ully resolv e on f ollow - up CT examinat ions, depending on t he grade of injury (21,348). T y pic ally , int raperit oneal blood and perisplenic hemat oma resolv e in 1 t o 3 w eeks. Int rasplenic hemat omas gradually dec rease in densit y and bec ome more sharply def ined as t he c lot s mat ure. T hey may go on t o c omplet e resolut ion, leav ing only a slight ly def ormed splenic margin, or t hey may f orm a post t raumat ic splenic pseudoc y st (89,107). Inf ec t ion may c omplic at e hemat oma resolut ion and produc e a splenic absc ess. Splenic lac erat ions usually resolv e in a f ew w eeks t o a f ew mont hs depending on t heir dept h and sev erit y . Splenic inf arc t s generally resolv e ov er sev eral mont hs. Alt hough it has been suggest ed by some aut hors t hat f ollow - up CT may be v aluable in demonst rat ing healing, and henc e allow earlier ret urn t o normal phy sic al

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3102 ac t iv it y (116), ot hers report t hat rout ine f ollow - up CT ev aluat ion is not nec essary or usef ul in c linic ally st able pat ient s t reat ed c onserv at iv ely (21,116,238,449).

Liver T he liv er is t he sec ond most f requent ly injured organ in blunt abdominal t rauma, and t he most c ommon abdominal injury leading t o deat h (113,318,403). Mort alit y t ends t o inc rease w it h inc reasing number and sev erit y of assoc iat ed ext rahepat ic injuries. As w it h splenic t rauma, assoc iat ed injury t o ot her abdominal organs is a c ommon oc c urrenc e. Conc omit ant injuries t o t he head, c hest , and ext remit ies also are f requent ly present (114). T raumat ic liv er injury most f requent ly inv olv es t he right hepat ic lobe, part ic ularly t he post erior segment (131,422). T his is bec ause t he right lobe c onst it ut es most of t he v olume of t he liv er and bec ause t he post erior segment of t he right lobe is readily ac c essible t o blunt impac t f rom t he ribs and spine (392,403). Right - sided rib f rac t ures hav e been report ed in up t o 33% of pat ient s w it h injuries t o t he right lobe of t he liv er (392). Relat iv e f ixat ion of t he liv er t o t he undersurf ac e of t he diaphragm and t o t he post erior abdominal w all by t he c oronary ligament s may also c ont ribut e t o t he predilec t ion f or right lobe injury (392). Lef t hepat ic lobe injuries are muc h less c ommon t han injuries t o t he right lobe and t end t o oc c ur w it h a f orc ef ul, direc t blow t o t he epigast rium. Lef t lobe injuries hav e a muc h higher assoc iat ion w it h injuries t o t he panc reas, duodenum, and t ransv erse c olon (205). CT is highly sensit iv e, spec if ic , and ac c urat e in def ining and c harac t erizing hepat ic injury (19,318,344,392,403). T he CT f indings of hepat ic injury are similar t o t hose seen in t he spleen and inc lude lac erat ion or f rac t ure t hrough t he hepat ic parenc hy ma, int raparenc hy mal hemat oma, and subc apsular hemat oma. Lac erat ions are t he most c ommon injury and appear as irregular linear, branc hing, or rounded areas of low at t enuat ion w it hin t he normally enhanc ing liv er parenc hy ma (113,392) (F ig. 21- 44). High- at t enuat ion f oc i of f reshly c lot t ed blood may be seen in t he areas of lac erat ion (F ig. 21- 45). Lac erat ions c ommonly parallel t he hepat ic or port al v enous v asc ulat ure and of t en ext end t o t he periphery of t he liv er. Lac erat ions t hat ext end t hrough t he liv er c apsule are usually assoc iat ed w it h hemoperit oneum (113,318). Parallel, linear lac erat ions on t he surf ac e of t he liv er or radiat ing out f rom t he hilar region may assume a c onf igurat ion t hat has been t ermed t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3103 P.1450 bear c law pat t ern bec ause of it s radiat ing, parallel, and jagged appearanc e (205,392) (F ig. 21- 46). On oc c asion, hepat ic lac erat ions may demonst rat e a branc hing pat t ern t hat simulat es t he appearanc e of unopac if ied port al or hepat ic v eins, or dilat ed bile duc t s (113,392). T his resemblanc e is usually limit ed t o a single CT sec t ion, and in most c ases, c aref ul analy sis of c ont iguous sec t ions allow s c orrec t diagnosis.

F igure 21- 44 Hepat ic lac erat ion. A, B: Comput ed t omography images demonst rat e an irregular, low - at t enuat ion lac erat ion (ar r ow ) in t he right hepat ic lobe. Not e het erogeneous early art erial phase c ont rast enhanc ement of t he spleen (S).

F igure 21- 45 Hepat ic lac erat ion. Not e irregular, low - at t enuat ion lac erat ion in t he post erior right lobe of t he liv er. High- at t enuat ion f oc i of c lot t ed blood (ar r ow s) are seen w it hin t he area of lac erat ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3104 Lac erat ions may be anat omic ally loc alized t o lobes and segment s, and f urt her c lassif ied as superf ic ial, perihilar, or deep. Deep lac erat ions, or lac erat ions ext ending bet w een t w o v isc eral surf ac es, may result in f ragment at ion of t he liv er, produc ing isolat ed nonperf used f ragment s. Part ial hepat ic dev asc ularizat ion c an oc c ur f rom lac erat ion of blood v essels in t he perihilar region or c omplet e av ulsion of t he dual blood supply of t he liv er, produc ing w edge- shaped, nonenhanc ing regions t hat ext end t o t he periphery (395,489). Lac erat ions ext ending int o t he perihilar region of t he liv er hav e an inc reased inc idenc e of bile duc t injury and assoc iat ed c omplic at ions suc h as biloma and hemobilia (205,392). Disrupt ion of t he biliary t ree is only rarely det ec t able on an init ial CT examinat ion, but may bec ome manif est on delay ed sc ans in t he f orm of a loc ulat ed int rahepat ic biloma or an ext rahepat ic bile c ollec t ion w it h at t enuat ion v alues t y pic ally near 0 HU. Alt hough small bilomas usually resolv e spont aneously , large or inc reasing bilomas may indic at e t he need f or perc ut aneous drainage or surgic al repair (19). lood along t he right hepat ic v ein and around t he inf erior v ena c av a (V) is also not ed.

F igure 21- 46 Bear c law t y pe lac erat ion of t he right hepat ic lobe. Not e roughly parallel, radiat ing, low - at t enuat ion lac erat ions inv olv ing t he dome of t he liv er. A small amount of perihepat ic blood is present (ar r ow ).

Int rahepat ic hemat omas appear as poorly marginat ed, c onf luent areas of low at t enuat ion w it hin t he hepat ic parenc hy ma (F igs. 21- 47 and 21- 48). T hey t end t o be rounded or ov al in c onf igurat ion and of t en display a c ent ral highat t enuat ion area of c lot t ed blood surrounded by a larger low - at t enuat ion region of ly sed c lot and c ont used liv er parenc hy ma (205,392). On pat hologic

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3105 examinat ion, int rahepat ic hemat omas hav e been f ound t o represent areas of mic rosc opic hemorrhage, nec rosis, and edema. Subc apsular hemat omas oc c asionally result f rom blunt t rauma, but more f requent ly are t he result of iat rogenic injuries suc h as perc ut aneous liv er biopsy . Subc apsular hemat omas usually appear on CT as peripheral, w ellmarginat ed, lent ic ular or c resc ent - shape f luid c ollec t ions P.1451 t hat c harac t erist ic ally f lat t en or indent t he underly ing liv er parenc hy ma. Most subc apsular hemat omas oc c ur along t he pariet al surf ac e of t he liv er, part ic ularly along t he ant erolat eral aspec t of t he right hepat ic lobe (361). T he at t enuat ion of t he c ollec t ion depends on t he age of t he hemat oma, generally being of higher at t enuat ion early w hen c lot t ed blood is present and t hen dec reasing in at t enuat ion ov er t ime as c lot ly sis t akes plac e (113,205,392).

F igure 21- 47 Int rahepat ic hemat oma. Cont rast - enhanc ed c omput ed t omography sc an demonst rat es a poorly marginat ed, c onf luent area of low at t enuat ion w it hin t he dome of t he liv er c onsist ent w it h an int raparenc hy mal hemat oma. Dissec t ion of blood along t he right hepat ic v ein and around t he inf erior v ena (v ) is also not ed.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3106

F igure 21- 48 Hepat ic lac erat ion and hemat oma. A, B: Comput ed t omography images demonst rat e ext ensiv e, irregular lac erat ion and int raparenc hy mal hemat oma (ar r ow s), oc c upy ing muc h of t he right lobe of t he liv er. T he injury ext ends c ent rally t o t he c onf luenc e of t he hepat ic v eins and inf erior v ena c av a (ar r ow head). Not e assoc iat ed perihepat ic and perisplenic hemorrhage (h). ST , st omac h.

Oc c asionally , hepat ic parenc hy mal or subc apsular gas may be seen in areas of hepat ic lac erat ion or hemat oma w it hin 2 t o 3 day s f ollow ing blunt abdominal t rauma (2,331) (F ig. 21- 49). Alt hough t he presenc e of hepat ic gas of t en indic at es t he presenc e of inf ec t ion, suc h gas may also be a manif est at ion of sev ere blunt t rauma w it hout inf ec t ion. It has been post ulat ed t hat t he gas arises f rom hepat ic isc hemia and nec rosis (283). In t he appropriat e c linic al set t ing, suc h gas- c ont aining injuries c an be t reat ed c onserv at iv ely w it hout t he need f or surgic al or perc ut aneous int erv ent ion (2,331,403).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3107 F igure 21- 49 Int rahepat ic hemat oma w it h st erile nec rosis. Cont rast enhanc ed c omput ed t omography sc an 3 day s f ollow ing blunt abdominal t rauma demonst rat es int raparenc hy mal hemat oma c ont aining sev eral small bubbles of gas (ar r ow s), presumably sec ondary t o nec rosis w it hin t he area of injury . T he pat ient had no ev idenc e of inf ec t ion and rec ov ered unev ent f ully . E, pleural ef f usion.

Periport al low at t enuat ion surrounding port al v enous branc hes (periport al t rac king) is seen in up t o 22% of pat ient s w it h blunt abdominal t rauma (259, 337,392, 393, 403,478) (F ig. 21- 50). P.1452 In pat ient s w it h hepat ic injury , t he periport al low at t enuat ion has been at t ribut ed t o dissec t ion of blood along t he c ourse of t he port al v eins (259). In t he absenc e of CT ev idenc e of hepat ic disrupt ion, how ev er, t he f inding of dif f use periport al low at t enuat ion af t er blunt t rauma should not be t aken as de f ac t o ev idenc e of underly ing hepat ic parenc hy mal injury (393). In most t rauma pat ient s, periport al t rac king most likely represent s dist ension of periport al ly mphat ic s and ly mphedema assoc iat ed w it h elev at ed c ent ral v enous pressure produc ed by rapid expansion of int rav asc ular v olume during v igorous f luid resusc it at ion (69,393). Ot her t rauma- relat ed pat hologic c hanges leading t o elev at ed c ent ral v enous pressure, suc h as t ension pneumot horax, peric ardial t amponade, or hemat oma obst ruc t ing hepat ic v enous out f low , also may result in dif f use periport al low at t enuat ion (230,393).

F igure 21- 50 Periport al low at t enuat ion. Comput ed t omography image demonst rat es periport al low at t enuat ion (ar r ow s) surrounding t he port al

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3108 t riads. A small amount of f luid is seen adjac ent t o t he inf erior v ena c av a (V).

Lac erat ions or hemat omas of t he hepat ic parenc hy ma c an be simulat ed by beam- hardening art if ac t f rom adjac ent ribs or st reak art if ac t s f rom air–c ont rast int erf ac es. Rib art if ac t s c an usually be ident if ied by t heir t y pic al loc at ion deep t o t he rib and by t heir t endenc y t o f ade and bec ome more dif f use as t hey proc eed int o t he liv er (140). Art if ac t s f rom air–c ont rast int erf ac es in st omac h and bow el generally are more regular and linear in appearanc e t han t rue lac erat ions. Lac erat ions also c an be simulat ed by c ongenit al hepat ic c lef t s or f issures (F ig. 21- 51). A lac erat ion or hemat oma c an be missed in c ases of f at t y liv er in w hic h t he low - at t enuat ion f at t y - inf ilt rat ed parenc hy ma, ev en w hen enhanc ed, remains isodense w it h t he areas of low - at t enuat ion injury . Assoc iat ed hemoperit oneum should remain ev ident , how ev er, and may be t he only readily ident if iable sign suggest ing hepat ic injury . In suc h c ases, it may be helpf ul t o v iew images of t he liv er w it h narrow w indow w idt hs (100 t o 200 HU) t o enhanc e det ec t ion of subt le parenc hy mal f indings, suc h as alt erat ion of t he c ourse of int rahepat ic v essels and duc t s w it hin t he areas of parenc hy mal injury (114,361). Int rahepat ic v asc ular injuries hav e been report ed in assoc iat ion w it h injuries of higher CT grade and sev erit y (343,344). Spec if ic v asc ular st ruc t ures t hat may be af f ec t ed inc lude t he major hepat ic v eins, t he inf erior v ena c av a (IVC), and t he hepat ic art ery (392). As w it h v asc ular injuries t o t he spleen, t here are sev eral CT signs of hepat ic v asc ular injury . Ac t iv e bleeding may be ident if ied on c ont rast - enhanc ed CT as irregular, round, or ov al areas of bright v asc ular enhanc ement in t he hepat ic parenc hy ma w it h CT at t enuat ion v alues usually w it hin 10 HU of an adjac ent art ery . Ac t iv e subc apsular or ext rahepat ic bleeding appears as an irregular blush of high- densit y c ont rast mat erial ext ending f rom t he liv er periphery int o a surrounding hemat oma (343,392). More rec ent ly , a number of aut hors hav e report ed c ont rast pooling on CT as a sign of ac t iv e hemorrhage (110,111). T he inc reasing v isualizat ion of t his sign may be a result of f ast er sc anning w it h MDCT , w hic h allow s smaller amount s of ac t iv e hemorrhage t o be det ec t ed bef ore t he high- densit y c ont rast mat erial is dilut ed by surrounding hemat oma. T he presenc e of pooling of c ont rast mat erial w it hin t he perit oneal c av it y indic at es ac t iv e and massiv e bleeding. Pat ient s w it h t his CT sc an f inding show rapid det eriorat ion of hemody namic st at us, and may require emergenc y surgery . Pooling of c ont rast mat erial in rupt ured hepat ic parenc hy ma also indic at es ac t iv e bleeding, requiring at least c lose monit oring and possibly emergent angiography and int erv ent ion. T he st at us of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3109 t he liv er c apsule, eit her int ac t or rupt ured, may help predic t w hic h pat ient s w ill det eriorat e hemody namic ally and w hic h pat ient s w ill be suc c essf ully t reat ed c onserv at iv ely (110). Hepat ic v ein damage has been not ed t o oc c ur in 10% t o 15% of liv er injuries, of t en as a result of av ulsion of t he right hepat ic v ein f rom t he IVC. Lac erat ions near t he c onf luenc e of t he hepat ic v eins or t he int rahepat ic IVC should suggest t he pot ent ial f or hepat ic v ein or IVC lac erat ion. Suc h injuries are of part ic ular c onc ern bec ause t hey c an result in rapid exsanguinat ion, part ic ularly w hen t he liv er is mobilized at t he t ime of surgic al inspec t ion (24,205). T he rec ognit ion of ac t iv e hemorrhage in t hese c ases is of major c linic al import anc e as it indic at es t he need f or possible surgic al or int erv ent ional t reat ment bec ause c onserv at iv e t herapy is unlikely t o be suc c essf ul (205). Pseudoaneury sms of t he hepat ic art ery may result f rom hepat ic lac erat ions ext ending ac ross t he hepat ic art eries. T hey represent c ont ained art erial perf orat ions and usually appear as disc ret e, ov al or round lesions w it hin t he hepat ic parenc hy ma t hat are isodense w it h adjac ent major art erial st ruc t ures (205). Not inf requent ly , hemat oma w ill be not ed t o surround t he pseudoaneury sm. Alt hough a signif ic ant perc ent age of pat ient s w it h hepat ic injury hav e obv ious signs of shoc k or perit onit is at t he t ime of admission and require immediat e surgery w it hout preliminary imaging st udies, t here are also a large number of pat ient s w it h signif ic ant hepat ic t rauma w ho P.1453 are hemody namic ally st able t hat may be best managed nonoperat iv ely . Nonoperat iv e management of liv er injuries in hemody namic ally st able pat ient s c an be expec t ed t o be suc c essf ul in up t o 90% of pat ient s in w hom it is used (75,131,269,303,343,478). Key s t o suc c essf ul nonoperat iv e management inc lude c onst ant hemody namic monit oring, serial c linic al and laborat ory assessment , blood replac ement as nec essary , and ready av ailabilit y of nursing, surgic al, and imaging f ac ilit ies in t he ev ent of hemody namic det eriorat ion (131,298).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3110

F igure 21- 51 Congenit al hepat ic c lef t . A: Comput ed t omography (CT ) sc an t hrough t he dome of t he liv er demonst rat es a deep c lef t in t he hepat ic parenc hy ma. B: On a CT image 1 c m c audal t o (A), t he peripheral c lef t mimic s a parenc hy mal lac erat ion. Not e t he absenc e of perihepat ic blood.

Sev eral at t empt s hav e been made t o grade liv er injury by means of CT t o help guide c linic al management . A CT - based grading sy st em adapt ed f rom t he AAST (T able 21- 3) (343) assesses t he loc at ion of hepat ic lac erat ions and hemat omas, as w ell as t he presenc e and ext ent of t issue dest ruc t ion and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3111 dev asc ularizat ion (298,343,344). Alt hough ref lec t iv e of t he degree of hepat ic parenc hy mal damage, t his CT grading sy st em, as w ell as ot hers, does not reliably predic t t he need f or surgic al or int erv ent ional t reat ment , nor does it help predic t t he out c ome of c onserv at iv e t reat ment (17,298,343,344). T he surgic al organ injury sc ale of t he AAST inc ludes some c rit eria t hat c annot be assessed w it h CT , and w ide disc repanc ies hav e been f ound bet w een t he CT injury grade and operat iv e f indings (74,344). Some low er grade injuries (grades 1 or 2) may require surgic al int erv ent ion, possibly bec ause of sev ere assoc iat ed injury P.1454 t o t he f alc if orm ligament not det ec t ed using CT . In addit ion, t he majorit y of pat ient s w it h ev en high- grade injuries (grades 3 or 4) and major hemoperit oneum may respond f av orably t o c onserv at iv e t reat ment (17,74,344). TABLE 21- 3 C OMPUTED TOMOGRAPHY - BASED INJURY SEVERITY OF HEPATIC TRAUMA Grade I

Capsular av ulsion, superf ic ial lac erat ion(s) less t han 1 c m deep, subc apsular hemat oma less t han 1 c m in maximum t hic kness, periport al blood t rac king only . Grade II Lac erat ion(s) 1 t o 3 c m deep, c ent ralsubc apsular hemat oma(s) 1 t o 3 c m in diamet er. Grade III Lac erat ion great er t han 3 c m deep, c ent ral- subc apsular hemat oma(s) great er t han 3 c m in diamet er. Grade IV Massiv e c ent ral- subc apsular hemat oma great er t han 10 c m, lobar t issue dest ruc t ion (mac erat ion) or dev asc ularizat ion. Grade V Bilobar t issue dest ruc t ion (mac erat ion) or dev asc ularizat ion. F rom Polet t i PA, Mirv is SE, Shanmuganat han K, et al. CT c rit eria f or management of blunt liv er t rauma: c orrelat ion w it h angiographic and surgic al f indings. Radiology 2000;216:418–427, w it h permission. CT c an be usef ul in monit oring t he healing of hepat ic injuries, c onf irming t he

resorpt ion of hemoperit oneum, and det ec t ing c omplic at ions suc h as hepat ic inf arc t ion, enlarging hemat oma, biloma, or absc ess f ormat ion (17,39, 131). Hemoperit oneum normally is resorbed f rom t he perit oneal c av it y , and in most c ases is eit her signif ic ant ly reduc ed or absent by 1 w eek af t er injury . Persist enc e of hemoperit oneum or inc rease in t he v olume of int raperit oneal f luid on repeat CT sc ans 3 t o 7 day s af t er injury suggest s eit her ongoing

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3112 int raperit oneal bleeding or bile leakage (131). Delay ed hemorrhage, or progression of init ially st able parenc hy mal injuries, is less c ommon w it h hepat ic t rauma t han w it h splenic injury (201,298). Subc apsular liv er hemat omas usually resolv e in 6 t o 8 w eeks. Int raparenc hy mal hemat omas heal muc h more slow ly , of t en requiring 6 mont hs t o sev eral y ears t o resolv e c omplet ely , bec ause bile in t he hemat oma prolongs c lot resorpt ion and adv ersely af f ec t s parenc hy mal healing (377). Lac erat ions heal more rapidly , w it h ev idenc e of signif ic ant healing generally not ed on serial CT examinat ions ov er a 2- t o 3- w eek period (131) (F ig. 21- 52). Hepat ic lac erat ions and hemat omas t y pic ally demonst rat e a dec rease in CT at t enuat ion v alue, as w ell as a slight inc rease in size on init ial f ollow - up CT st udies (i.e., 7 day s post injury ), probably as a result of osmot ic absorpt ion of f luid. Irregular margins of lac erat ions and hemat omas bec ome bet t er def ined w it h healing and t end t o assume a rounded or ov oid c onf igurat ion w it h resolut ion (131). Suc h lesions may progressiv ely dec rease in size or t hey may persist as w ell- def ined hepat ic c y st s or bilomas (377).

Gallbladder T he gallbladder is inf requent ly injured in blunt abdominal t rauma, w it h a report ed inc idenc e of 2% t o 6% (392). T he low inc idenc e of gallbladder injury may be bec ause of t he prot ec t iv e ef f ec t of t he liv er (42). Gallbladder injury is usually assoc iat ed w it h injuries t o ot her organs, most c ommonly t he liv er, spleen, and duodenum (52). T raumat ic injuries t o t he gallbladder inc lude c ont usion, lac erat ion, perf orat ion, and c omplet e av ulsion (392,403). CT f indings inc lude peric holec y st ic f luid (most c ommon), blurring of t he c ont our of t he gallbladder, f oc al t hic kening or disc ont inuit y of t he gallbladder w all, an enhanc ing muc osal f lap w it hin t he lumen, mass ef f ec t on t he adjac ent duodenum, and high- densit y int raluminal blood (19,392,403). A c ollapsed gallbladder, c oupled w it h addit ional imaging signs of gallbladder injury , should raise t he possibilit y of gallbladder perf orat ion or av ulsion (163). Av ulsion of t he gallbladder may inv olv e v ariable port ions of t he gallbladder, c y st ic duc t , and c y st ic art ery and may lead t o major blood loss (52).

Pancreas Panc reat ic injuries f rom t rauma are relat iv ely unc ommon, ac c ount ing f or only 3% t o 12% of all abdominal injuries (11,95,132,208). Depending on pat ient

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3113 demographic s, blunt or penet rat ing t rauma ac c ount s f or t he majorit y of panc reat ic injuries (5,130). Generally , penet rat ing panc reat ic injuries arise f rom gunshot w ounds or st ab w ounds (5). T he mec hanism of injury t o t he panc reas in blunt t rauma is t hought t o be c ompression of t he panc reas bet w een t he v ert ebral c olumn and t he ant erior abdominal w all, of t en as a result of direc t st eering w heel injury (in adult s) or bic y c le handlebar injury (in c hildren) t o t he midepigast rium (95,209). In 50% t o 98% of c ases, panc reat ic injuries are assoc iat ed w it h injuries t o ot her int raabdominal organs (119,473), and t his c ombinat ion of injuries result s in a mort alit y rat e of approximat ely 20%, as c ompared w it h a mort alit y rat e of 3% t o 10% f or isolat ed panc reat ic injuries (473). Most deat hs w it hin t he f irst 48 hours are a result of hemorrhage f rom ext rapanc reat ic injuries (132,209). Delay s in diagnosis c an lead t o inc reased lat e (great er t han 48 hours post injury ) morbidit y and mort alit y relat ed t o t he panc reat ic injuries alone (248). In general, inc reasing sev erit y of panc reat ic injury is c orrelat ed w it h inc reasing sev erit y and ext ent of ext rapanc reat ic injury (130). T he diagnosis of panc reat ic injury c an be ext remely dif f ic ult bec ause t he c linic al, laborat ory , and radiographic f indings are highly v ariable and nonspec if ic (11). Clinic al manif est at ions of panc reat ic injury , suc h as abdominal pain and leukoc y t osis, f requent ly are mild, absent , or masked by assoc iat ed injuries (72,314). Serum amy lase lev els may be elev at ed, but t his is not inv ariably t he c ase, and init ial serum amy lase det erminat ions hav e been report ed t o be normal in up t o 40% of pat ient s w it h panc reat ic injury (209). P.1455 Ev en w it h t ot al disrupt ion of t he panc reat ic duc t al sy st em, amy lase lev els may not be elev at ed unt il 24 t o 48 hours post injury . In addit ion, t he degree of serum amy lase elev at ion does not c orrelat e w it h t he degree of panc reat ic injury (132). Bec ause panc reat ic injuries may be c linic ally oc c ult or unrec ognized, t hey of t en are disc ov ered at t he t ime of laparot omy f or ot her know n int raabdominal injuries (60,207,327).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3114

F igure 21- 52 Healing hepat ic lac erat ions on serial c omput ed t omography (CT ) examinat ions. A: Init ial sc an demonst rat es bear c law –t y pe lac erat ion in t he right lobe of t he liv er. B: Sc an 4 day s lat er show s dec rease in CT at t enuat ion v alue and slight inc rease in size of t he hepat ic lac erat ions, probably a result of osmot ic absorpt ion of f luid. C : On a sc an 3 w eeks lat er, t he lac erat ions hav e assumed a more rounded c onf igurat ion, and t he margins of t he lac erat ions are bet t er def ined. D: F ollow - up sc an 3 mont hs af t er t he init ial injury demonst rat es v irt ually c omplet e resolut ion of t he liv er lac erat ions.

Panc reat ic injuries c an range f rom minor parenc hy mal c ont usions and hemat omas t o major lac erat ions or f rac t ures w it h assoc iat ed panc reat ic duc t disrupt ion. CT has been report ed t o diagnose panc reat ic injury in 67% t o P.1456

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3115 85% of c ases (204,410), w it h a spec if ic it y of 98% (25,130, 196). T he sensit iv it y of CT f or diagnosis of t raumat ic panc reat ic injury is likely t o improv e in t he f ut ure w it h t he use of MDCT , t hinner c ollimat ion, and highqualit y mult iplanar rec onst ruc t ion. On c ont rast - enhanc ed CT , c ont usions generally appear as f oc al low at t enuat ion areas w it hin t he normally enhanc ing panc reat ic parenc hy ma. Lac erat ions or f rac t ures appear as linear, irregular regions of low at t enuat ion, of t en orient ed perpendic ular t o t he long axis of t he panc reas (323) (F igs. 2153 and 21- 54). F rac t ures most c ommonly oc c ur in t he panc reat ic nec k or body w here t he panc reas ov erlies t he spine, alt hough some f rac t ures hav e been report ed in t he panc reat ic head or t ail (25,91,252). Hemat omas, pseudoc y st s, and absc esses are of t en seen c ommunic at ing w it h t he panc reas at t he sit e of f rac t ure or t ransec t ion (163). T he rare appearanc e of ac t iv e panc reat ic bleeding is pat hognomonic of panc reat ic injury (25). Addit ional suggest iv e but nonspec if ic signs of panc reat ic injury inc lude f oc al enlargement of t he panc reas, inf ilt rat ion of t he peripanc reat ic f at and mesent ery , t hic kening of t he lef t ant erior renal f asc ia (204), t rac king of f luid bet w een t he splenic v ein and panc reas (236), and f luid in t he ant erior pararenal spac e or lesser sac (408). Panc reat ic lac erat ion or f rac t ure may be dif f ic ult t o ident if y ac ut ely (less t han 12 hours post injury ) w it h CT bec ause of obsc urat ion of t he f rac t ure plane by hemorrhage and/or c lose apposit ion of t he lac erat ed parenc hy mal f ragment s (204). As t he t ime f rom injury progresses, edema, inf lammat ion, and aut odigest ion by exuded panc reat ic enzy mes P.1457 of t en make t he CT f indings of panc reat ic injury more apparent . T hus, if suspic ion of panc reat ic injury persist s despit e init ially normal CT f indings, repeat CT sc ans in 12 t o 24 hours may be w arrant ed (91,275).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3116

F igure 21- 53 Panc reat ic lac erat ion w it h disrupt ion of t he panc reat ic duc t . A: Comput ed t omography sc an demonst rat es lac erat ion t hrough t he t ail of t he panc reas (open ar r ow ). F luid is seen about t he t ail of t he panc reas (solid ar r ow s) adjac ent t o t he spleen (S). B: Endosc opic ret rograde c holangiopanc reat ography (ERCP) demonst rat es disrupt ion of t he main panc reat ic duc t in t he t ail of t he panc reas w it h ext rav asat ion of c ont rast mat erial (ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3117

F igure 21- 54 Panc reat ic lac erat ion. A, B: Comput ed t omography images t hrough t he panc reas (P) demonst rat e peripanc reat ic f luid (ar r ow heads) t rac king int o t he lef t ant erior pararenal spac e. Not e irregular, low - at t enuat ion lac erat ion (ar r ow ) ext ending t hrough t he body of t he panc reas. Adjac ent f luid surrounds t he superior mesent eric v ein (a). F luid is also present in t he hepat orenal f ossa (ast er isk).

One ret rospec t iv e rev iew of t he CT f indings in pat ient s w it h t raumat ic panc reat ic injury suggest ed t hat most c ases of missed diagnosis c ould be av ert ed w it h c aref ul sc rut iny of t he images, dec reased CT slic e t hic kness (5 mm or less), and appropriat e CT t ec hnique, inc luding proper administ rat ion of IV c ont rast mat erial (25). Also st ressed w as t he need t o t horoughly examine t he panc reas despit e t he dist rac t ing presenc e of prof ound ext rapanc reat ic injuries. When panc reat ic injury is ev ident on CT , it may be dif f ic ult t o ac c urat ely grade t he sev erit y of t he injury . T here are v ary ing report s on t he ef f ic ac y of CT f or grading panc reat ic injury , w it h some report s not ing underest imat ion of injury sev erit y (5,196,336) w hile ot hers report ov erest imat ion (482). F alse–posit iv e diagnosis of panc reat ic lac erat ion or f rac t ure may result f rom st reak art if ac t s, phy siologic t hinning of t he panc reat ic nec k (F ig. 21- 55), or misint erpret at ion of unopac if ied proximal jejunal loops as t he panc reat ic body , separat ed f rom t he panc reat ic head and nec k region by a f at plane around t he mesent eric v essels (114). In quest ionable c ases, repeat delay ed sc ans w it h addit ional oral c ont rast mat erial usually demonst rat es c hanges in shape and opac if ic at ion of t he bow el loops, allow ing c orrec t diagnosis. CT c annot direc t ly assess t he int egrit y of t he panc reat ic duc t , w hic h is t he princ ipal det erminant in t he management of panc reat ic injuries (66). One st udy

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3118 assessing CT grading of blunt panc reat ic injuries suggest ed t hat duc t al disrupt ion w as likely t o be present if CT sc ans demonst rat ed a deep lac erat ion or t ransec t ion of t he panc reas (482). In general, how ev er, def init iv e det erminat ion of panc reat ic duc t int egrit y requires eit her endosc opic ret rograde c holangiopanc reat ography (ERCP), int raoperat iv e ev aluat ion (51,119), or, more rec ent ly , MR panc reat ography (336). MR panc reat ography has t he adv ant age of being noninv asiv e, f ast er, and more readily av ailable t han ERCP (163). In addit ion t o ident if y ing t he main panc reat ic duc t in most c ases (134), MR panc reat ography is helpf ul in assessing parenc hy mal injury , and in demonst rat ing f luid c ollec t ions assoc iat ed w it h panc reat ic duc t lac erat ion or t ransec t ion (418).

Bowel and Mesentery Injuries t o t he bow el and mesent ery are report ed t o oc c ur in 3% t o 5% of pat ient s sust aining blunt abdominal t rauma (37,397). T hey are most of t en assoc iat ed w it h mot or v ehic le ac c ident s, and t heir prev alenc e has inc reased w it h t he use of lap- t y pe seat - belt rest raint s, part ic ularly in c hildren (79,390,413). Mec hanisms of injury inc lude direc t c ompression of t he bow el bet w een t he v ert ebral c olumn and t he ant erior abdominal w all, a sudden marked inc rease in int raluminal pressure, and shearing- t y pe injury near sit es of mesent eric f ixat ion, suc h as t he ligament of T reit z and t he ileoc ec al junc t ion (70,85,193). Bow el injuries c an range f rom f oc al mural c ont usions or hemat omas t o c omplet e t ransec t ions. T hey most c ommonly inv olv e t he duodenum, usually t he sec ond and t hird port ions, alt hough t his predilec t ion ov er ot her small bow el injuries does v ary w it h geographic loc at ion (50,193). Colonic injuries f ollow ing blunt abdominal t rauma are less c ommon t han eit her duodenal or ot her small bow el injuries (188). T raumat ic injuries t o t he c olon are more likely t o inv olv e t he more v ulnerable t ransv erse and P.1458 sigmoid c olon, w it h damage t o t he right c olon ac c ompanied by mult iple ot her injuries and rec t al injury assoc iat ed w it h pelv ic f rac t ure (193,206). Prompt diagnosis of int est inal or mesent eric injury is of t en dif f ic ult bec ause signs and sy mpt oms may be delay ed and phy sic al examinat ion is neit her sensit iv e nor spec if ic (43,93). Early c linic al f indings are f requent ly subt le, and t he c lassic t riad of t enderness, rigidit y , and absent bow el sounds only oc c urs in about 30% of pat ient s (43). Abdominal w all bruising, or t he “ seat - belt sign,” should inc rease suspic ion f or bow el and mesent eric injury (193).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3119 Children present ing w it h iliac w ing f rac t ures f rom improperly posit ioned lap belt s are at high risk f or suc h injuries (102).

F igure 21- 55 Pseudof rac t ure of t he panc reas due t o phy siologic t hinning of t he panc reat ic nec k. A: Comput ed t omography (CT ) sc an at t he lev el of t he superior mesent eric v ein–splenic v ein c onf luenc e demonst rat es apparent f rac t ure of t he panc reat ic nec k (open ar r ow ). B: CT sc an 1 c m c audal t o (A) show s f at in t he region of t he nec k c onsist ent w it h phy siologic t hinning. Not e also t he absenc e of peripanc reat ic f luid.

Clear- c ut perit oneal signs and sy mpt oms c an t ake hours or day s t o dev elop in st able pat ient s w it h int est inal injury bec ause of minimal blood loss, c ont ained ret roperit oneal inv olv ement in some duodenal and c olonic injuries, and t he nonirrit at iv e c omposit ion (i.e., neut ral pH) and low bac t erial c ount s of small bow el c hy me (93,397). Changes in laborat ory v alues also dev elop ov er t ime.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3120 One st udy f ound c orrelat ion bet w een an inc reased base def ic it and small bow el and mesent eric injuries (133). Anot her st udy f ound t hat signif ic ant ly more pat ient s w it h small bow el injury dev eloped leukoc y t osis w it hin 3 hours of present at ion t han did pat ient s w it h ot her int raabdominal injuries (170). P.1459 As prev iously disc ussed, diagnost ic perit oneal lav age (DPL) is highly sensit iv e f or hemoperit oneum but not at all spec if ic f or t he sourc e of t he bleeding, and may miss ret roperit oneal hemorrhage (7,344). One st udy f ound t hat alt hough DPL w as sensit iv e f or int raabdominal injuries in general, it w as not as usef ul in ident if y ing isolat ed small bow el and mesent eric injuries (133). US has been show n, in t he hands of an experienc ed operat or, t o be highly sensit iv e in t he rapid det ec t ion of int raperit oneal f luid (491), and in many c ent ers, has replac ed DPL. In addit ion, sonography has been f ound t o be usef ul in ident if y ing int ramural bow el hemat omas (253,490) and solid organ parenc hy mal injuries. If undiagnosed, bow el perf orat ion c an lead t o f at al perit onit is. A delay of more t han 24 hours in diagnosis and surgic al repair of bow el perf orat ion result s in a signif ic ant inc rease in morbidit y (146,254,360). Whet her or not t here is an inc rease in mort alit y , how ev er, has been rec ent ly debat ed in t he lit erat ure, w it h some st udies f inding delay ed diagnosis t o hav e no impac t on deat h rat es (7,14,133). One st udy f oc using on small bow el injury f ound t hat a delay in diagnosis of longer t han 8 hours did result in signif ic ant ly inc reased mort alit y (108). Undiagnosed mesent eric injuries c an lead t o int est inal st enosis present ing w eeks af t er t he init ial t rauma (80,251,447). In general, undiagnosed bow el and mesent eric injuries ev olv e w it h t ime, af f ec t ing t he pat ient 's phy sic al c ondit ion. In many c ases of missed diagnosis w it h onset of new signs and sy mpt oms, a repeat CT sc an w ill show more def init iv e ev idenc e of injury (7,156) (F ig. 21- 56). CT has been show n t o be usef ul f or det ec t ing bow el and mesent eric injuries c aused by blunt t rauma, but c aref ul inspec t ion and met ic ulous sc anning t ec hnique are required t o det ec t of t en subt le f indings (286,316,344,397). In a ret rospec t iv e st udy of blunt duodenal injury , t he aut hors f ound t hat CT f indings of bow el injury w ere present in 83% of pat ient s w it h missed diagnoses, and t hey surmised t hat t hese f indings w ere ov erlooked in t he c ont ext of mult iple assoc iat ed injuries (7). Alt hough many earlier st udies f ound poor sensit iv it y of CT f or det ec t ion of bow el injuries (48,66,216,266,276,398), more rec ent st udies hav e report ed higher sensit iv it y of CT f or diagnosing bow el and mesent eric injuries and f or dist inguishing t hose injuries t hat are

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3121 likely t o require surgic al int erv ent ion (40,94,98,286,359,397). One st udy f ound t hat CT dif f erent iat ed surgic al f rom nonsurgic al injuries in 86% of bow el c ases and 75% of mesent eric c ases (220), w hile anot her report ed a 75% suc c ess rat e at dif f erent iat ion (200). Current st udies report sensit iv it ies of CT f or t he diagnosis of bow el and mesent eric injuries ranging f rom 64% t o 96% (18,44,192,200,220,261,268), but t hese hav e all inv olv ed ret rospec t iv e rev iew s, most hav e analy zed small c ohort s of pat ient s, and of t en t he CT rev iew ers w ere not blinded t o t he pat ient s' surgic al diagnosis. F urt hermore, in t hese st udies, t he CT f indings c onsidered diagnost ic of bow el and mesent eric injury v aried, and some used c onv ent ional CT w hile ot hers used helic al CT and st ill ot hers used a c ombinat ion of bot h t ec hnologies. Larger, prospec t iv e st udies w it h c onsist ent ly def ined diagnost ic c rit eria are needed t o ac c urat ely assess t he sensit iv it y of modern CT in t he diagnosis of bow el and mesent eric injury . T he use of MDCT promises t o great ly improv e t he sensit iv it y and spec if ic it y of CT f or t raumat ic bow el and mesent eric injuries. T he inc reased speed, w hic h eliminat es mot ion art if ac t , higher z- axis resolut ion, and t hinner c ollimat ion allow superior v isualizat ion of t he bow el and mesent eric v asc ulat ure (184,185). Slic es as t hin as 0.5 mm and speeds of eight slic es per sec ond are obt ainable on t he eight - det ec t or sc anners, and t his c ollimat ion and speed is surpassed by sc anners w it h addit ional det ec t ors (186). T y pic ally , slic es of P.1460 1.25 mm are used t o ev aluat e t he bow el and mesent ery . MDCT angiography c an generat e det ailed v iew s of t he mesent eric art eries and v eins, and MDCT c olonosc opy prov ides a noninv asiv e means t o examine t he c olon lumen. Indiv idual loops of small bow el c an be v isualized using 3D rec onst ruc t ion (186). When MDCT is immediat ely av ailable in t he t rauma depart ment , obt aining CT ev aluat ion is f easible in ev en unst able pat ient s (466).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3122 F igure 21- 56 Missed jejunal perf orat ion. A: Comput ed t omography (CT ) sc an of t he midabdomen demonst rat es t hic kened jejunal loops (ar r ow s) in t he lef t upper quadrant . Small amount of f luid/blood also is not ed surrounding t hese loops and adjac ent t o t he desc ending c olon (c ). No ext raluminal gas w as f ound. B: Repeat CT sc an 2 day s af t er (A) show s marked inc rease in t he amount of int raperit oneal f luid. Ext raluminal gas c ollec t ions (ar r ow s) are now c learly v isible. Surgery c onf irmed jejunal perf orat ion. (Case c ourt esy of Christ ine O Menias, M.D., St . Louis, MO.)

CT signs of bow el and mesent eric injury inc lude ext raluminal air, ext rav asat ion of oral c ont rast mat erial, f ree int raabdominal f luid, t hic kened and/or disc ont inuous bow el w all, high- at t enuat ion c lot (sent inel c lot ) adjac ent t o t he inv olv ed bow el, and st reaky sof t t issue inf ilt rat ion of t he mesent eric f at (94,252,286,316,325,344,359) (F ig. 21- 57). F ree air in eit her t he perit oneal c av it y or t he ret roperit oneum is a relat iv ely spec if ic sign of bow el perf orat ion but is seen in only 50% of c ases (87,146,359). T he v olume of air may be quit e small and subt le (245). T o opt imize det ec t ion of ext raluminal air and t o f ac ilit at e it s dif f erent iat ion f rom int raluminal air and f rom f at , images should be v iew ed at w ide w indow set t ings (i.e., lung w indow s) (see F ig. 21- 57) (70,397). Pneumoperit oneum is most c ommonly seen in t he subdiaphragmat ic area, along t he ant erior perit oneal surf ac es of t he liv er and spleen. Ext raluminal air also may be present w it hin t he leav es of t he mesent ery (F ig. 21- 58) or in t he ret roperit oneum, part ic ularly in t he ant erior pararenal spac e (316,478). Oc c asionally , int raperit oneal or ret roperit oneal gas result s f rom ext raperit oneal dissec t ion of air f rom t raumat ic injuries of t he t horax (pneumot horax, pneumomediast inum) or bladder (bladder rupt ure) and is not relat ed t o bow el t rauma (40,66,344). Addit ionally , pneumoperit oneum may oc c ur iat rogenic ally , f ollow ing diagnost ic perit oneal lav age or c hest t ube plac ement (18). Ext rav asat ion of oral c ont rast mat erial f rom t he bow el lumen is c onsidered diagnost ic of bow el perf orat ion but is seen in only a minorit y of c ases (70,87,359) (F ig. 21- 59). T here has been some c ont rov ersy ov er t he use of oral c ont rast mat erial in t rauma pat ient s, w it h some aut hors c laiming an inc reased P.1461 risk of v omit ing and aspirat ion w it hout improv ed diagnost ic c apabilit y (57,446), w hile ot hers assert t hat oral c ont rast mat erial is saf e and improv es v isualizat ion of bow el injuries (117,286,311,316). A rec ent ret rospec t iv e st udy f ound t hat MDCT w it hout oral c ont rast mat erial w as adequat e f or depic t ion of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3123 bow el and mesent eric injuries requiring surgic al repair, and t hat t heir result s w ere c omparable t o prev iously report ed dat a f or single- det ec t or row helic al CT w it h oral c ont rast mat erial (432). Bot h posit iv e oral c ont rast agent s, suc h as sodium amidot rizoat e/meglumine amidot rizoat e (Gast rograf in) or barium, and neut ral agent s, suc h as w at er, are c ommonly used (186). Wat er allow s f or bet t er dist inc t ion bet w een t he opac if ied v asc ulat ure, t he enhanc ed bow el w all, and t he bow el lumen, but does not prov ide as muc h bow el dist ension as t he posit iv e agent s bec ause of a higher bow el t ransit t ime (186). Wat er is of t en used f or MDCT bec ause posit iv e agent s may degrade nonaxial rec onst ruc t ed images (367).

F igure 21- 57 Jejunal perf orat ion. A: Comput ed t omography image demonst rat es a markedly t hic kened loop of jejunum (j), w it h f ree f luid (ar r ow heads) t rac king along t he post erior aspec t of t he jejunum and int o t he mesent ery . B, C : Images at a slight ly higher lev el demonst rat e addit ional perijejunal f luid (ar r ow head) on sof t t issue w indow set t ings, and sev eral f oc i of ext raluminal air (ar r ow s) on lung w indow set t ings.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3124

F igure 21- 58 Jejunal perf orat ion. Comput ed t omography images t hrough t he low er abdomen (A, B) demonst rat e t hic k- w alled jejunum (J), sof t t issue inf ilt rat ion of t he adjac ent mesent eric f at (c ur v ed ar r ow s), and ext raluminal mesent eric air (st r aight ar r ow ).

Int raabdominal f luid is a v ery c ommon but nonspec if ic CT f inding of bow el or mesent eric injury (286,359). T he f luid may be of low at t enuat ion, represent ing ext rav asat ed small bow el c ont ent s, or of int ermediat e t o high at t enuat ion f rom ac ut e hemorrhage. F ree int raperit oneal f luid in t he absenc e of an apparent solid v isc eral sourc e of hemorrhage P.1462 should height en suspic ion of a bow el or mesent eric injury (33,170,286,359). Oc c asionally , small quant it ies of int raperit oneal f luid, part ic ularly w hen loc alized in t he small bow el mesent ery or bet w een loops of bow el, may be t he only CT sign of bow el perf orat ion. Moderat e or large amount s of f luid are less

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3125 c ommon as t he sole CT abnormalit y but hav e a higher likelihood of being assoc iat ed w it h bow el or mesent eric injury (246). Ot her suggest iv e but nonspec if ic abnormalit ies, suc h as f oc al bow el w all t hic kening or st randy sof t t issue inf ilt rat ion of t he mesent eric f at , c an improv e diagnost ic ac c urac y w hen c ombined w it h ot her CT sc an f indings (40,94, 245,344). One st udy , inc luding ov er 2,000 pat ient s w it h small bow el injury (SBI), used a logist ic regression model t o ident if y CT signs t hat best predic t SBI. T he f inal model inc luded f ree f luid, pneumoperit oneum, and bow el w all t hic kening, result ing in a sensit iv it y f or SBI of 75% and a spec if ic it y of 79.1% (109). In anot her st udy , t he CT f indings of mesent eric bleeding and bow el w all t hic kening assoc iat ed w it h mesent eric hemat oma or inf ilt rat ion indic at ed a high likelihood of a mesent ery bow el injury requiring surgic al int erv ent ion (99) (F ig. 21- 60).

F igure 21- 59 Small bow el lac erat ion at t he ligament of T reit z w it h ext rav asat ion of oral c ont rast mat erial. Comput ed t omography images at t he lev el of t he t ransv erse duodenum (A) and low er pole of t he lef t kidney (B) demonst rat e ext rav asat ed oral c ont rast mat erial along t he small bow el mesent ery (st r aight ar r ow s) and in t he lef t parac olic gut t er (c ur v ed ar r ow ). Ill- def ined hemorrhage is not ed at t he root of t he mesent ery (open ar r ow ). D,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3126 opac if ied t ransv erse duodenum; J, unopac if ied jejunum; K, low er pole of lef t kidney .

Int ramural hemorrhage is det ec t ed in most pat ient s w it h bow el injury as c irc umf erent ial or ec c ent ric t hic kening of t he bow el w all on CT , of t en w it h assoc iat ed luminal narrow ing (191,235). Int ense enhanc ement of t he bow el w all has also been report ed as a sign of bow el injury (168,409). When c ombined w it h bow el w all t hic kening and f ree perit oneal f luid, int ense bow el w all enhanc ement suggest s bow el perf orat ion and perit onit is (168). It should be not ed, how ev er, t hat inc reased c ont rast enhanc ement of t he bow el w all is not a spec if ic sign of bow el rupt ure bec ause it c an also be seen in c hildren w it h t he hy poperf usion c omplex and in adult s w it h c ompromised c ent ral v enous ret urn or prolonged hy poperf usion result ing in so- c alled shoc k bow el (294,364). P.1463

Kidney

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3127 F igure 21- 60 Mesent eric art erial hemorrhage. A: Comput ed t omography (CT ) image demonst rat es hemoperit oneum (h) sec ondary t o surgic ally prov en mesent eric art erial bleeding at t he lev el of t he mid desc ending c olon (c ). Not e ac t iv e art erial ext rav asat ion of c ont rast mat erial (ar r ow s). B, C : In anot her pat ient w it h rec ent abdominal t rauma, CT images demonst rat e irregular c ollec t ions of iodinat ed c ont rast mat erial (t hic k ar r ow s) in t he mesent ery , represent ing pseudoaneury sms. Non–c ont rast - enhanc ed ac ut e blood is seen in t he mesent ery (t hin ar r ow ) and right ant erior pararenal spac e (H).

T rauma t o t he kidney c an oc c ur eit her as an isolat ed ev ent or, more f requent ly , as c onc omit ant injury in pat ient s w it h ac ut e abdominal t rauma. Worldw ide, blunt t rauma is responsible f or 80% of renal injuries, but t he number at t ribut able t o penet rat ing w ounds inc reases dramat ic ally in urban set t ings w it h a high rat e of v iolent c rime (167). Most c losed renal injuries are a result of mot or v ehic le ac c ident s, w it h c ont ac t sport s, f alls, f ight s, and assault s ac c ount ing f or t he remainder. Wit h blunt t rauma, t he kidney may be injured by a direc t blow , lac erat ed by t he low er ribs, or t orn by rapid ac c elerat ion–dec elerat ion (31,345). Penet rat ing injuries are usually sec ondary t o gunshot or st ab w ounds. Int erv ent ional proc edures, suc h as perc ut aneous nephrost omy and renal biopsy , c onst it ut e anot her group of penet rat ing injuries. A diseased or anomalous kidney is more susc ept ible t o injury t han a healt hy one. Minor or t riv ial t rauma may lead t o disrupt ion of a hy dronephrot ic renal pelv is, f rac t ure of a f ragile, inf ec t ed kidney , or lac erat ion of a poorly prot ec t ed ec t opic or horseshoe kidney (F ig. 21- 61). Preexist ing renal disease should be suspec t ed w henev er t he inc it ing t rauma seems disproport ionat ely t riv ial t o t he pat ient 's c linic al f indings (36,128). Children are more likely t han adult s t o sust ain t raumat ic injuries t o t he kidney bec ause t he pediat ric kidney is less w ell prot ec t ed, larger w it h respec t t o t he body , and f requent ly ret ains f et al lobulat ions, w hic h inc rease susc ept ibilit y t o parenc hy mal lac erat ion (350). Renal injuries c an be div ided int o f our broad c at egories, originally desc ribed by F ederle, based on a c ombinat ion of c linic al and imaging f indings (115,212). Cat egory I lesions inc lude c ont usions, nonexpanding subc apsular hemat omas, and small c ort ic omedullary lac erat ions t hat do not c ommunic at e w it h t he c ollec t ing sy st em. T hey ac c ount f or 75% t o 85% of all renal injuries. Cat egory II lesions c onsist of deep lac erat ions t hat ext end int o t he medulla, w it h or w it hout c ommunic at ion w it h t he renal c ollec t ing P.1464

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3128 sy st em, and ac c ount f or about 10% of c ases. Lesions in c at egory III c onsist of shat t ered kidney s and injuries t o t he renal v asc ular pedic le. T hey c omprise about 5% of t he t ot al. Cat egory IV w as est ablished f or t he relat iv ely unc ommon ent it y of uret eropelv ic junc t ion (UPJ) av ulsion and lac erat ion of t he renal pelv is. T he AAST dev eloped an alt ernat e renal injury sc ale t hat inc ludes f iv e grades and is based on dept h and number of parenc hy mal lac erat ions. Bot h sy st ems of c at egorizat ion appear in t he CT lit erat ure.

F igure 21- 61 Dev asc ularizat ion injury of a pelv ic kidney . A: Pelv ic kidney (st r aight ar r ow s) is ident if ied just t o t he lef t of t he sigmoid c olon (S). Illdef ined region of low at t enuat ion along t he post erior margin of t he kidney represent s t he superior aspec t of an area of dev asc ularizat ion inv olv ing t he low er pole. B: Comput ed t omography image 2 c m c audal t o (A) demonst rat es a w ell- demarc at ed area of hy poperf usion inv olv ing t he post erior half of t he low er pole of t he pelv ic kidney (st r aight ar r ow s). Cur v ed ar r ow , uret er f rom pelv ic kidney .

Most surgeons agree t hat c at egory I injuries are best managed nonoperat iv ely , w hereas c at egory IV injuries require prompt surgery (161,166). Cont rov ersy exist s as t o t he proper management of c at egory II and III lesions, w it h opinions ranging f rom ext reme c onserv at ism t o aggressiv e int erv ent ion (46,106,169,488). In a st udy of c onserv at iv e management of c at egory II and III injuries w it h urinary ext rav asat ion, t he aut hors report ed dec reased morbidit y and short er hospit al st ay s f or pat ient s w ho did not exhibit dev it alized renal segment s (308). T hose pat ient s w it h dev asc ularized parenc hy ma of t en required ev ent ual surgic al int erv ent ion. T hese f indings hav e been c onf irmed in addit ional report s (358,376). In ot her st udies, suc c essf ul superselec t iv e t ransart erial embolizat ion f or renov asc ular injuries, inc luding

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3129 shat t ered kidney , has been report ed (88,166). T hese injuries may inc reasingly be t reat ed w it h minimally inv asiv e means. Main renal v ein injury and sev ere bilat eral renal t rauma remain c onsist ent indic at ions f or surgic al int erv ent ion (166). Unlike c losed renal injuries, w hic h generally are managed more c onserv at iv ely , penet rat ing renal t rauma usually is an indic at ion f or surgery . Gunshot w ounds almost inv ariably require surgic al explorat ion and debridement bec ause of t he prev alenc e of assoc iat ed injuries, c ont aminat ion by f oreign mat erial (e.g., c lot hing), and ext ensiv e t issue nec rosis produc ed by t heir blast ef f ec t s (161). One st udy of selec t iv e management of gunshot w ounds report ed suc c essf ul kidney preserv at ion w it h c onserv at iv e management in pat ient s w ho present ed w it hout hilar inv olv ement or persist ent hemorrhage (457). St ab w ounds of t he kidney , onc e an inc ont rov ert ible indic at ion f or surgery , are now being managed by w at c hf ul expec t anc y in selec t ed c ases bec ause of t he prec ise inf ormat ion prov ided by noninv asiv e imaging met hods (161,417). In t he absenc e of assoc iat ed injuries, c linic al f indings of t he pat ient w it h a renal injury are dic t at ed by t he t y pe and sev erit y of renal t rauma. Renal injury must be presumed in ev ery pat ient w it h abdominal t rauma w ho has gross or mic rosc opic hemat uria. In one report of 38 c hildren af t er blunt abdominal t rauma, t he amount of hemat uria c orrelat ed bet t er t han hy pot ension w it h t he sev erit y of renal injury (421). How ev er, in anot her report of 254 c hildren, only 51% of t hose sent f or surgic al explorat ion f or sev ere renal injuries present ed w it h gross hemat uria (350). In 10% t o 28% of pat ient s w it h renal t rauma, hemat uria may be absent , espec ially t hose w it h injuries t o t he renal pedic les (270). Bec ause rapid dec elerat ion is a c ommon c ause of renal pedic le injury , it is prudent t o subjec t all pat ient s P.1465 w it h dec elerat ion injuries (e.g., head- on mot or v ehic le c ollision, f all f rom a height ) t o renal imaging, regardless of t he presenc e or absenc e of hemat uria (31). T he role of t he radiologist in assessing pat ient s w it h suspec t ed renal t rauma is t o ac c urat ely def ine t he nat ure and ext ent of renal damage so t hat t he maximum amount of f unc t ioning renal parenc hy ma c an be preserv ed w it h t he f ew est c omplic at ions. T he c hoic e of imaging st udies depends upon t he c ondit ion of t he pat ient , t he av ailabilit y of imaging resourc es and personnel, and t he surgeon's approac h t o management of renal t rauma.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3130 CT is t he most inf ormat iv e radiologic st udy in renal t rauma. A c omplet e CT examinat ion of t he abdomen and pelv is c an be c omplet ed w it h ease and speed using st at e- of - t he- art CT sc anners. T he use of CT is no longer limit ed t o t he ev aluat ion of pat ient s w it h sev ere renal t rauma, suspec t ed mult iorgan t rauma, or penet rat ing t rauma. CT is c ommonly used as t he init ial imaging st udy in all st abilized pat ient s w it h abdominal and renal t rauma (226,474, 488), in ev ery set t ing f rom major t rauma c ent ers t o rural emergenc y depart ment s (150). IV urography is usef ul in t he gross assessment of kidney st at us in unst able pat ient s (212) and st ill is used oc c asionally in some inst it ut ions t o ev aluat e st able, asy mpt omat ic pat ient s w it h a hist ory of minor, loc alized renal t rauma. A normal urogram obv iat es f urt her imaging ev aluat ion in t his c linic al set t ing. CT is perf ormed only in pat ient s w it h persist ent hemat uria or a f alling hemat oc rit . CT also is perf ormed if t he prior urogram suggest s major injury or is inc onc lusiv e. Ult rasonography and radionuc lide sc int igraphy generally are not used as init ial imaging st udies in renal t rauma. Color Doppler ult rasonography c an demonst rat e subc apsular or perinephric hemat omas and v asc ular injuries, but has limit ed c apac it y t o ev aluat e t he renal parenc hy ma and c annot demonst rat e urinary ext rav asat ion (213,272,341, 456). Radionuc lide imaging c an be used t o assess residual renal f unc t ion af t er c onserv at iv e t reat ment of renal injury (488). Art eriography is reserv ed f or preoperat iv e road mapping and f or t herapeut ic int erv ent ions, suc h as embolizat ion of bleeding v essels and art eriov enous f ist ulas. As t he qualit y of 3D rec onst ruc t ion of CT images c ont inues t o improv e, MDCT w it h 3D mult iplanar rec onst ruc t ion may prov ide a noninv asiv e alt ernat iv e t o perioperat iv e angiography in t he f ut ure (165,384). In spit e of it s abilit y t o demonst rat e v asc ular pat enc y and parenc hy mal abnormalit ies (c ont usions and lac erat ions), MRI of f ers f ew adv ant ages ov er w ell- perf ormed c ont rast - enhanc ed CT and is not used in ac ut e sit uat ions (232,243). A c omplet e CT ev aluat ion of renal t rauma inc ludes bot h early and delay ed enhanc ed sc ans (213,456). T he early c ont rast - enhanc ed sc ans ac quired during t he c ort ic omedullary phase opt imize v asc ular opac if ic at ion and v isualizat ion of c ont rast mat erial ext rav asat ion. Delay ed sc ans perf ormed at 5 t o 15 minut es f ollow ing IV c ont rast mat erial administ rat ion c apt ure t he exc ret ory phase of t he kidney , allow ing assessment of t he c ollec t ing sy st em. Art erial- phase sc ans c an improv e v isualizat ion of t raumat ic pseudoaneury sms, w hic h oc c ur more c ommonly w it h penet rat ing t rauma but c an be assoc iat ed

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3131 w it h blunt injuries (299). T he c apabilit y of CT t o ev aluat e renal t rauma w ill undoubt edly improv e w it h t he inc reased speed and t hinner c ollimat ion of MDCT . T he use of MDCT urography t o ev aluat e nont raumat ic urinary t rac t abnormalit ies has y ielded exc ellent result s, part ic ularly in imaging of t he c ollec t ing sy st em and t he small, pediat ric kidney (45,49, 274,349). In one st udy , t he aut hors c ompared MDCT urography and t radit ional IV urography and report ed as good or bet t er opac if ic at ion of t he ent ire c ollec t ing sy st em and uret ers w it h MDCT (274). CT is c apable of demonst rat ing v irt ually t he ent ire spec t rum of renal injury and ef f ec t iv ely rev eals preexist ing renal abnormalit ies. T he mildest f orm of renal injury is a c ont usion (F ig. 21- 62). Renal c ont usion appears on unenhanc ed sc ans as dif f use or f oc al sw elling c ont aining sc at t ered f oc i of high- densit y f resh blood int ermixed w it h normally homogeneous sof t t issue at t enuat ion renal parenc hy ma. T he inv olv ed area of t en exhibit s delay ed and dec reased enhanc ement af t er IV administ rat ion of iodinat ed c ont rast medium (345). A st riat ed nephrogram, presumably result ing f rom st asis of urine in blood- f illed t ubules, also has been enc ount ered (370). Parenc hy mal lac erat ions likew ise c an be rec ognized on CT . T hey appear as unenhanc ed areas disrupt ing t he normally enhanc ing renal parenc hy ma on c ont rast - enhanc ed sc ans (F ig. 21- 63). Bot h c ont usions and small parenc hy mal lac erat ions are of t en ac c ompanied by a small subc apsular or perirenal hemorrhage. Whereas subc apsular hemat omas generally appear as lent ic ular c ollec t ions t hat P.1466 f lat t en t he underly ing renal c ont our, perirenal hemat omas inf ilt rat e or displac e perirenal f at and may ext end t o t he renal (Gerot a's) f asc ia (F ig. 21- 64).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3132

F igure 21- 62 Renal c ont usion. Comput ed t omography image demonst rat es a f oc al area of low at t enuat ion in t he post erior aspec t of t he lef t kidney represent ing renal c ont usion (ar r ow s).

F igure 21- 63 Renal lac erat ion. Comput ed t omography image at t he lev el of t he renal v eins demonst rat es an irregular, linear, low - at t enuat ion renal lac erat ion (ar r ow ) ext ending f rom t he right renal hilum t o t he renal c apsule. A lef t renal c ont usion (ar r ow heads) is also present . T he hemoperit oneum w as relat ed t o c onc omit ant splenic injury .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3133 Cat egory II injuries are easily det ec t ed on enhanc ed CT as parenc hy mal def ec t s ext ending f rom t he renal surf ac e int o t he medulla, w here t hey may ent er t he c ollec t ing sy st em and/or t ransec t t he kidney (F ig. 21- 65). T y pic ally , suc h renal “ f rac t ures” parallel int erv asc ular t issue planes, of t en w it hout t earing major art eries or v eins (386). T he parenc hy mal margins of t en enhanc e inhomogeneously , produc ing a mot t led appearanc e (386). T w o- and t hreedimensional rec onst ruc t ions c an be helpf ul in depic t ing t he t opography of renal lac erat ions (384). Cat egory II injuries are almost alw ay s ac c ompanied by perirenal hemorrhage. Ext rav asat ion of opac if ied urine, int o eit her renal parenc hy ma or t he perirenal spac e, f requent ly oc c urs (see F ig. 21- 65). An admixt ure of urine and blood also may be seen in t he leav es of renal f asc ia as w ell as t he ant erior pararenal spac e (404). Cat ast rophic renal injuries (c at egory III) inc lude shat t ered kidney and renal v asc ular pedic le injury . A shat t ered or pulv erized kidney is rec ognized on CT as mult iple f rac t ure planes separat ing enhanc ing or nonenhanc ing renal f ragment s (F ig. 21- 66). In c ont radist inc t ion t o t he “ f rac t ures” in c at egory II lesions, f rac t ures assoc iat ed w it h a shat t ered kidney generally shear ac ross segment al renal blood v essels. A large perirenal hemat oma is inv ariably present w it h a shat t ered kidney . In renal pedic le injury , t he oc c luded or av ulsed main renal art ery c an be depic t ed on c ont rast - enhanc ed helic al CT (56,267,321). In suc h an injury , a normal- sized, nonenhanc ing kidney is ident if ied (F ig. 21- 67). A rim of c ort ic al t issue may be perf used by subc apsular c ollat eral v essels (147,257), alt hough t his f inding may not be not ed ac ut ely . Ot her assoc iat ed f indings inc lude hemat oma surrounding t he renal hilus, abrupt c ut of f of t he c ont rast - f illed renal art ery , small perinephric hemat oma, and ret rograde f illing of t he renal v ein (47). Disrupt ion of a branc h v essel result s in a segment al inf arc t t hat appears as a w edge- or hemispheric - shaped zone of underperf used renal parenc hy ma subt ending t he dist ribut ion of t he oc c luded v essel. A w edgeshaped inf arc t is t y pic ally orient ed w it h it s base direc t ed t ow ard t he renal c apsule and it s apex t ow ard t he renal hilus (147). T hrombosis of t he renal art ery is prec eded by int imal t earing. Disrupt ion of t he int ima leads t o dissec t ion, art erial st enosis, and, f inally , c lot f ormat ion. Of t en t he injury is det ec t ed only af t er t he oc c lusion. Cont rast - enhanc ed helic al CT has been report ed t o det ec t asy mmet ric renal enhanc ement sec ondary t o

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3134 renal art ery dissec t ion, enabling st ent ing or rec onst ruc t ion of t he lesion prior t o t hrombosis (90,320). Renal v ein injury oc c urs in 20% of pat ient s w it h solit ary pedic le injury (112). Ac ut e renal v ein oc c lusion may produc e an enlarged rat her t han a normalsized kidney , and assoc iat ed c ort ic al rim enhanc ement is usually t hic ker t han w it h art erial obst ruc t ion (148). Demonst rat ion of t hrombus w it hin a dilat ed renal v ein on CT c onf irms t he diagnosis (23). Venography may be required t o det ec t v enous lac erat ions (213). CT f indings of massiv e ac c umulat ion of ext rav asat ed urine in t he medial rat her t han dorsolat eral aspec t of t he perirenal spac e, absenc e of renal parenc hy mal injury , and lac k of uret eral opac if ic at ion should suggest t he diagnosis of UPJ disrupt ion (c at egory IV injury ) (214,217,388). One P.1467 st udy f ound t hat UPJ injury w as missed at t he aut hors' inst it ut ion bec ause t he sc an delay f ollow ing IV c ont rast mat erial administ rat ion w as t oo short (approximat ely 45 t o 60 sec onds) t o allow f or opac if ic at ion of t he renal c ollec t ing sy st em (38). Repeat sc ans upon c omplet ion of t he init ial sc ans c onsist ent ly rev ealed t he UPJ disrupt ions. T hus, delay ed sc ans at 5 t o 15 min af t er t he IV administ rat ion of c ont rast mat erial are rec ommended t o adequat ely ev aluat e f or UPJ injury (213,309,347,462). Ret rograde uret eropy elography should be perf ormed t o c onf irm t he diagnosis prior t o surgic al c orrec t ion.

F igure 21- 64 Renal lac erat ion w it h perirenal hemat oma. Cont rast - enhanc ed c omput ed t omography sc an demonst rat es a right renal lac erat ion (t hic k

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3135 ar r ow ) w it h assoc iat ed perirenal hemat oma c onf ined by t he post erior renal (Gerot a's) f asc ia (t hin ar r ow ). T he pat ient also has int raperit oneal blood (H) f rom a rupt ured spleen.

F igure 21- 65 Renal f rac t ure. A: Cont rast - enhanc ed c omput ed t omography sc an demonst rat es f rac t ured lef t low er renal pole (K) w it h large perirenal hemat oma (H). B: Delay ed sc an show s ext rav asat ion of opac if ied urine int o t he perirenal spac e (ar r ow ).

Ureter Iat rogenic t rauma sec ondary t o surgic al proc edures is t he leading c ause of uret eral injury (237). Penet rat ing and blunt t rauma ac c ount f or a relat iv ely small number of uret eral injuries. When present , t hey c ommonly are assoc iat ed w it h renal parenc hy mal, art erial, and v enous injuries (444). Most report ed c ases are hy perext ension injuries sust ained by c hildren in mot or v ehic le c ollisions. CT f indings of isolat ed uret eral disrupt ion in adult s inc lude nonv isualizat ion of t he uret er dist al t o t he point of disrupt ion, int ac t P.1468 renal parenc hy ma, and c onf inement of ext rav asat ed urine t o t he medial perirenal spac e (217). In c hildren, how ev er, t he urine ext rav asat ion also expands int o leav es of t he renal f asc ia, ant erior pararenal spac e, and t he psoas c ompart ment (404).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3136

F igure 21- 66 Shat t ered kidney w it h large perirenal hemat oma. Ac t iv e bleeding is not ed in t he lef t perirenal spac e ant eriorly (st r aight ar r ow s). Small liv er lac erat ion (c ur v ed ar r ow ) and blood in t he hepat orenal f ossa are also ev ident .

F igure 21- 67 Renal pedic le injury w it h dev asc ularizat ion of t he lef t kidney . Comput ed t omography sc an at t he lev el of t he lef t renal hilum demonst rat es absent perf usion of t he lef t kidney (K). Blood t rac ks along an unenhanc ed lef t renal art ery (t hic k ar r ow ). A diminut iv e lef t renal v ein (t hin ar r ow ) and a small amount of hemorrhage (H) in t he lef t ant erior pararenal spac e are also not ed. (Case c ourt esy of Kev in Smit h, M.D., Birmingham, Alabama.)

Bladder

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3137 Bladder injuries may oc c ur as a result of blunt , penet rat ing, or iat rogenic t rauma. T he susc ept ibilit y of t he bladder t o injury v aries w it h t he degree of dist ension; a dist ended urinary bladder is muc h more prone t o injury t han a nearly empt y one. Most pat ient s w it h bladder rupt ure c omplain of suprapubic pain or t enderness; how ev er, t he disc omf ort assoc iat ed w it h a f rac t ured bony pelv is of t en obsc ures t he pain assoc iat ed w it h t he urinary t rac t injury . Gross hemat uria almost inv ariably ac c ompanies bladder injury . In one report ed series (330), 95% of pat ient s w it h bladder rupt ure had gross hemat uria and t he remainder had mic rosc opic hemat uria. T he t y pe of urine ext rav asat ion (int raperit oneal or ext raperit oneal) is dependent on t he loc at ion of t he bladder t ear and it s relat ionship t o t he perit oneal ref lec t ions (375). Wit h an ant erosuperior perf orat ion, ext rav asat ion may be eit her int raperit oneal, int o t he prev esic al spac e (spac e of Ret zius), or bot h. Wit h a post erosuperior t ear, f luid c an spread int raperit oneally , ret roperit oneally , or bot h. Ext rav asat ion may also ext end inf eriorly int o t he perineum, t he sc rot um, and t he t high, if t he urogenit al diaphragm is disrupt ed. Int raperit oneal rupt ure usually result s f rom a direc t blow (of t en a kic k) t o a dist ended bladder and requires surgic al repair. Ext raperit oneal rupt ure of t en result s f rom a shearing injury at t he base of t he bladder and is best t reat ed w it h suprapubic c y st ost omy (67). If ext raperit oneal rupt ure oc c urs in t he set t ing of pelv ic f rac t ure requiring int ernal f ixat ion, how ev er, t he rupt ure may be surgic ally repaired t o prot ec t t he ort hopedic hardw are f rom ext rav asat ed urine and pot ent ial inf ec t ion (83). Radiographic ev aluat ion of t he low er urinary t rac t is w arrant ed in c ases of gross hemat uria w it h pelv ic f rac t ure, gross hemat uria w it h unexplained pelv ic f luid, or signs of P.1469 perineal t rauma, suc h as v oiding dif f ic ult ies, bleeding f rom t he uret hra, perineal hemat oma, or elev at ion of t he prost at e on digit al exam (304,306,462). One st udy f ound t hat c ert ain pelv ic f rac t ures, inc luding pubic sy mphy sis diast asis, sac roiliac diast asis, and sac ral, iliac , and pubic rami f rac t ures, w ere signif ic ant ly assoc iat ed w it h bladder rupt ure (306). CT c y st ography has replac ed c onv ent ional c y st ography as t he st udy of c hoic e f or suspec t ed bladder injury and c an be done in c onc ert w it h CT ev aluat ion of assoc iat ed injuries. If uret hral t rauma is suspec t ed, a ret rograde uret hrogram should prec ede CT c y st ography .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3138

F igure 21- 68 Bladder hemat oma. T here is a large mural hemat oma (H) inv olv ing t he bladder base. A large amount of blood is also seen f illing t he pelv is. Not e t he hemat oc rit ef f ec t w it h denser blood element s lay ering post eriorly adjac ent t o t he rec t um (ar r ow ). T he pat ient had mult iple liv er lac erat ions on c omput ed t omography sc ans of t he abdomen. U, ut erus.

F igure 21- 69 Int raperit oneal bladder rupt ure. A: Image t hrough t he pelv is f rom a c omput ed t omography c y st ogram demonst rat es dif f usely t hic kened bladder w all. Blood is seen bot h in t he presac ral spac e (t hin ar r ow ) and prev esic al spac e (ar r ow ). B: Image t hrough t he low er abdomen show s ext rav asat ed iodinat ed c ont rast mat erial out lining t he bow el loops.

Alt hough c onv ent ional CT has perf ormed poorly in t he diagnosis of bladder rupt ure (164,189,332), sev eral st udies hav e demonst rat ed t hat properly

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3139 exec ut ed CT c y st ography is as sensit iv e f or det ec t ing bladder injuries as c onv ent ional c y st ography (183,210,250,339,453). In one c ohort of 316 pat ient s, t he aut hors report ed ov erall sensit iv it y and spec if ic it y of CT c y st ography as 95% and 100% respec t iv ely f or det ec t ion of surgic ally c onf irmed bladder rupt ure (82,83). Int raperit oneal rupt ure w as diagnosed w it h a sensit iv it y of 78% and a spec if ic it y of 99%. Reasons f or a f alse–negat iv e CT c y st ogram inc lude inadequat e bladder dist ension, t he presenc e of hemat oma or t issue edema prev ent ing ext rav asat ion, misint erpret at ion, ov erly dilut e c ont rast mat erial, and poor qualit y sc ans (82,164). T o minimize f alse–negat iv e CT diagnosis of bladder rupt ure, sc ans of t he pelv is should be obt ained w it h t he urinary bladder f ully dist ended eit her by ret rograde or ant egrade means (183,210,250). Ant egrade dist ension is f ac ilit at ed by c lamping t he urinary c at het er onc e sat isf ac t ory urine out put has been est ablished (462). Ret rograde bladder f illing c an be ac c omplished by inst illat ion of 300 t o 400 mL of 2% t o 4% c ont rast mat erial. F illing w it h less t han 250 mL c an result in f alse–negat iv e sc ans. Bot h delay ed sc ans and repeat sc anning of t he pelv is af t er bladder drainage hav e been used t o help det ec t subt le bladder injury (183,210,407), alt hough t heir usef ulness and prac t ic alit y hav e been debat ed (306). MDCT has been used in nont rauma pat ient s t o perf orm v irt ual c y st osc opy . One rec ent st udy c ompared t he f indings of v irt ual c y st osc opy w it h t hose of c onv ent ional c y st osc opy in pat ient s w it h gross hemat uria (221). T he sensit iv it y and spec if ic it y of v irt ual c y st osc opy w ere 95% and 93% f or det ec t ing abnormal bladders. T his t ec hnology may prov e usef ul f or det ec t ing subt le bladder injury . Angiography play s no role in t he primary assessment of bladder injury but may be of c onsiderable v alue in t he diagnosis and management of art erial bleeding assoc iat ed w it h pelv ic f rac t ures. Radionuc lide sc int igraphy c an det ec t small amount s of ext rav asat ion w it h great sensit iv it y , but bec ause of it s inf erior spat ial resolut ion c ompared w it h c onv ent ional radiography and CT it is rarely used in assessing c ases of bladder t rauma. Alt hough ult rasonography also may demonst rat e lac erat ions of t he urinary bladder (464), it is not w idely used in t he Unit ed St at es f or t his purpose. T est ing diagnost ic perit oneal lav age f luid f or elev at ed c reat inine has been usef ul in t he diagnosis of int raperit oneal rupt ure t hat may be ov erlooked on CT (81).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3140 Dif f erent t y pes of bladder injuries c an be ident if ied and dif f erent iat ed f rom one anot her on CT (453). Bladder c ont usion or hemat oma appears as f oc al or dif f use w all t hic kening w it hout ext rav asat ion of P.1470 c ont rast medium (F ig. 21- 68). Wit h int raperit oneal rupt ure of t he bladder, ext rav asat ed urine and c ont rast medium c an be f ound surrounding t he bladder or bow el and pooling in t he parac olic gut t ers (375) (F ig. 21- 69). Ext raperit oneal rupt ure result s in ext rav asat ion of c ont rast medium and urine int o t he prev esic al f at , ant erior t high, sc rot um, penis, and abdominal w all (F ig. 21- 70). Cont rast medium also c an ext end c ephalad t o t he perirenal and pararenal spac es (375). Dist inguishing int raperit oneal f rom ext raperit oneal rupt ure c an be dif f ic ult in some c ases. Care must be t aken w hen post eriorly ext rav asat ed c ont rast media f rom ext raperit oneal rupt ure appears c ont iguous w it h int raperit oneal pelv ic f luid bec ause t he separat ing perit oneum is so t hin (387).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3141

F igure 21- 70 Ext raperit oneal bladder rupt ure. A: T ransaxial image f rom a c omput ed t omography c y st ogram demonst rat es ext rav asat ion of iodinat ed c ont rast mat erial (ar r ow s) f rom t he urinary bladder (B) int o t he ext raperit oneal prev esic al spac e. U, ut erus. B: Coronal image demonst rat es t he sit e of bladder rupt ure (ar r ow ). Mult iple pelv ic f rac t ures are present . C : Sagit t al image c learly show s t he size and sit e (t hic k ar r ow ) of t he c ont rast ext rav asat ion f rom t he urinary bladder (B) int o t he prev esic al spac e (t hin ar r ow ). F , F oley balloon.

REFERENCES 1. Nat ional Cent er f or Injury Prev ent ion and Cont rol. Av ailable at : ht t p://w w w .w ebapp.c dc .gov /c gi- bin/broker.exe.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3142 2. Abramson SJ, Berdon WE, Kauf man RA, et al. Hepat ic parenc hy mal and subc apsular gas af t er hepat ic lac erat ion c aused by blunt abdominal t rauma. AJR Am J Roent genol 1989;153:1031–1032. 3. Abu- Zidan F M, Sheikh M, Jadallah F , et al. Blunt abdominal t rauma: c omparison of ult rasonography and c omput ed t omography in a dist ric t general hospit al. Aust r alas Radiol 1999;43: 440–443. P.1471 4. Agee CK, Met zler MH, Churc hill RJ, et al. Comput ed t omographic ev aluat ion t o exc lude t raumat ic aort ic disrupt ion. J T r aum a 1992;33:876–881. 5. Akhrass R, Y af f e MB, Brandt CP, et al. Panc reat ic t rauma: a t en- y ear mult iinst it ut ional experienc e. Am Sur g 1997;63:598–604. 6. Alkadhi H, Wildermut h S, Desbiolles L, et al. Vasc ular emergenc ies of t he t horax af t er iat rogenic t rauma: mult i- det ec t or row CT and t hree- dimensional imaging. Radiogr aphic s 2004;24:1239–1255. 7. Allen GS, Moore F A, Cox CS Jr, et al. Delay ed diagnosis of blunt duodenal injury : an av oidable c omplic at ion. J Am Coll Sur g 1998;187:393–399. 8. Aronc hic k JM, Epst ein DM, Gef t er WE, et al. Chronic t raumat ic diaphragmat ic hernia: t he signif ic anc e of pleural ef f usion. Radiology 1988;168:675–678. 9. Aseerv at ham R, Muller M. Blunt t rauma t o t he spleen. Aust N Z J Sur g 2000;70:333–337. 10. Ay ella RJ, Hankins JR, T urney SZ, et al. Rupt ured t horac ic aort a due t o blunt t rauma. J T r aum a 1977;17:199–205. 11. Bac h RD, F rey CF . Diagnosis and t reat ment of panc reat ic t rauma. Am J Sur g 1971;121:20–29. 12. Bac ker CL, LoCic ero J, Hart z RS, et al. Comput ed t omography in pat ient s w it h esophageal perf orat ion. Chest 1990;98:1078–1080. 13. Ball T , Mc Crory R, Smit h JO, et al. T raumat ic diaphragmat ic hernia: errors in diagnosis. AJR Am J Roent genol 1982;138:633–637. 14. Ballard RB, Badellino MM, Ey non CA, et al. Blunt duodenal rupt ure: a 6y ear st at ew ide experienc e. J T r aum a 1997;43:229–232; disc ussion 233. 15. Barc ia T C, Liv oni JP. Indic at ions f or angiography in blunt t horac ic t rauma. Radiology 1983;147:15–19. 16. Baxt WG, Moody P. T he impac t of a rot orc raf t aeromedic al emergenc y c are serv ic e on t rauma mort alit y . JAMA 1983;249: 3047–3051.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3143 17. Bec ker CD, Gal I, Baer HU, et al. Blunt hepat ic t rauma in adult s: c orrelat ion of CT injury grading w it h out c ome. Radiology 1996; 201:215–220. 18. Bec ker CD, Ment ha G, Sc hmidlin F , et al. Blunt abdominal t rauma in adult s: role of CT in t he diagnosis and management of v isc eral injuries. Part 2: gast roint est inal t rac t and ret roperit oneal organs. Eur Radiol 1998;8:772–780. 19. Bec ker CD, Ment ha G, T errier F . Blunt abdominal t rauma in adult s: role of CT in t he diagnosis and management of v isc eral injuries. Part 1: liv er and spleen. Eur Radiol 1998;8:553–562. 20. Bennet t , DE, Cherry , JK. T he nat ural hist ory of t raumat ic aneury sms of t he aort a. Sur ger y 1967;61:516–523. 21. Beny a EC, Bulas DI, Eic helberger MR, et al. Splenic injury f rom blunt abdominal t rauma in c hildren: f ollow - up ev aluat ion w it h CT . Radiology 1995;195:685–688. 22. Bergin D, Ennis R, Keogh C, et al. T he “ dependent v isc era” sign in CT diagnosis of blunt t raumat ic diaphragmat ic rupt ure. AJR Am J Roent genol 2001;177:1137–1140. 23. Berkov ic h GY , Ramc handani P, Preat e DL Jr, et al. Renal v ein t hrombosis af t er mart ial art s t rauma. J T r aum a 2001;50: 144–145. 24. Berland LL. CT of blunt abdominal t rauma. In: F ishman EK, F ederle MP, eds. Body CT c at egor ic al c our se sy llabus. New Orleans, LA: Americ an Roent gen Ray Soc iet y , 1994:207–214. 25. Bigat t ini D, Bov erie JH, Dondelinger RF . CT of blunt t rauma of t he panc reas in adult s. Eur Radiol 1999;9:244–249. 26. Blac k WC, Gouse JC, Williamson BR, et al. Comput ed t omography of t raumat ic lung c y st : c ase report . J Com put T om ogr 1986;10:33–35. 27. Bladergroen MR, Low e JE, Post let hw ait RW. Diagnosis and rec ommended management of esophageal perf orat ion and rupt ure. Ann T hor ac Sur g 1986;42:235–239. 28. Blair E, T opuzlu C, Dav is JH. Delay ed or missed diagnosis in blunt c hest t rauma. J T r aum a 1971;11:129–145. 29. Boulanger BR, Mirv is SE, Rodriguez A. Magnet ic resonanc e imaging in t raumat ic diaphragmat ic rupt ure: c ase report s. J T r aum a 1992;32:89–93. 30. Boy d AD. Pneumot horax and hemot horax. In: Hood RM, Boy d AD, Cullif ord AT , eds. T hor ac ic t r aum a, ed.[SD4] Philadelphia, PA: WB Saunders, 1989:133–148.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3144 31. Brandes SB, Mc Aninc h JW. Urban f ree f alls and pat t erns of renal injury : a 20- y ear experienc e w it h 396 c ases. J T r aum a 1999;47: 643–649; disc ussion 649–650. 32. Brasel KJ, St af f ord RE, Weigelt JA, et al. T reat ment of oc c ult pneumot horac es f rom blunt t rauma. J T r aum a 1999;46:987–990; disc ussion 990–991. 33. Breen DJ, Janzen DL, Zw irew ic h CV, et al. Blunt bow el and mesent eric injury : diagnost ic perf ormanc e of CT signs. J Com put Assist T om ogr 1997;21:706–712. 34. Bridges KG, Welc h G, Silv er M, et al. CT det ec t ion of oc c ult pneumot horax in mult iple t rauma pat ient s. J Em er g Med 1993;11:179–186. 35. Brooks AP, Olson LK. Comput ed t omography of t he c hest in t he t rauma pat ient . Clin Radiol 1989;40:127–132. 36. Brow er P, Paul J, Brosman SA. Urinary t rac t abnormalit ies present ing as a result of blunt abdominal t rauma. J T r aum a 1978;18:719–722. 37. Brow n RA, Bass DH, Rode H, et al. Gast roint est inal t rac t perf orat ion in c hildren due t o blunt abdominal t rauma. Br J Sur g 1992;79: 522–524. 38. Brow n SL, Hof f man DM, Spirnak JP. Limit at ions of rout ine spiral c omput erized t omography in t he ev aluat ion of blunt renal t rauma. J Ur ol 1998;160:1979–1981. 39. Bulas DI, Eic helberger MR, Siv it CJ, et al. Hepat ic injury f rom blunt t rauma in c hildren: f ollow - up ev aluat ion w it h CT . AJR Am J Roent genol 1993;160:347–351. 40. Bulas DI, T ay lor GA, Eic helberger MR. T he v alue of CT in det ec t ing bow el perf orat ion in c hildren af t er blunt abdominal t rauma. AJR Am J Roent genol 1989;153:561–564. 41. Bunt ain WL, Gould HR, Maull KI. Predic t abilit y of splenic salv age by c omput ed t omography . J T r aum a 1988;28:24–34. 42. Burgess P, F ult on L. Gallbladder and ext rahepat ic biliary duc t injury f ollow ing abdominal t rauma. Injur y 1992;23:413–414. 43. Burney RE, Mueller GL, Coon GL, et al. Diagnosis of isolat ed small bow el injury . Ann Em er g Med 1983;12:71–74. 44. But ela ST , F ederle MP, Chang PJ, et al. Perf ormanc e of CT in det ec t ion of bow el injury . AJR Am J Roent genol 2001;176:129–135. 45. Caoili EM, Cohan RH, Korobkin M, et al. Urinary t rac t abnormalit ies: init ial experienc e w it h mult i- det ec t or row CT urography . Radiology 2002;222:353–360.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3145 46. Cass AS. Disc ussion. In: Guerriero, WG, ed. Pr oblem s in ur ology , Philadelphia, PA: Lippinc ot t Williams & Wilkins, 1988:184. 47. Cat es JD, F oley WD, Law son T L. Ret rograde opac if ic at ion of renal v ein: a CT sign of renal art ery av ulsion. Ur ol Radiol 1986;8: 92–94. 48. Ceraldi CM, Waxman K. Comput erized t omography as an indic at or of isolat ed mesent eric injury : a c omparison w it h perit oneal lav age. Am Sur g 1990;56:806–810. 49. Chai RY , Jhav eri K, Saini S, et al. Comprehensiv e ev aluat ion of pat ient s w it h haemat uria on mult i- slic e c omput ed t omography sc anner: prot oc ol design and preliminary observ at ions. Aust r alas Radiol 2001;45:536–538. 50. Champion MP, Ric hards CA, Boddy SA, et al. Duodenal perf orat ion: a diagnost ic pit f all in non- ac c ident al injury . Ar c h Dis Child 2002;87:432–433. 51. Chapman WC, Morris JA. Diagnosis and management of blunt panc reat ic injury . J T enn Med Assoc 1989;82:84–85. 52. Chen X, T alner LB, Jurkov ic h GJ. Gallbladder av ulsion due t o blunt t rauma. AJR Am J Roent genol 2001;177:822. 53. Chew F S, Panic ek DM, Heit zman ER. Lat e disc ov ery of a post t raumat ic right aort ic arc h aneury sm. AJR Am J Roent genol 1985;145: 1001–1002. 54. Chiles C, Put man CE. Ac ut e t horac ic t rauma. In: Goodman LR, Put man CE, eds. Cr it ic al c ar e im aging, 3rd ed. Philadelphia, PA: WB Saunders, 1992:199–212. 55. Cholankeril JV, Zamora BO, Ket y er S. Lef t lobe of t he liv er draping around t he spleen: a pit f all in c omput ed t omography diagnosis of perisplenic hemat oma. J Com put T om ogr 1984;8: 261–267. 56. Chow dhary SK, Pimpalw ar A, Narasimhan KL, et al. Blunt injury of t he abdomen: a plea f or CT . Pediat r Radiol 2000;30: 798–800. P.1472 57. Clanc y T V, Ragozzino MW, Ramshaw D, et al. Oral c ont rast is not nec essary in t he ev aluat ion of blunt abdominal t rauma by c omput ed t omography . Am J Sur g 1993;166:680–684; disc ussion 684–685. 58. Clark DE, Zeiger MA, Wallac e KL, et al. Blunt aort ic t rauma: signs of high risk. J T r aum a 1990;30:701–705. 59. Cogbill T H, Moore EE, Jurkov ic h GJ, et al. Nonoperat iv e management of blunt splenic t rauma: a mult ic ent er experienc e. J T r aum a 1989;29:1312–1317. 60. Cogbill T H, Moore EE, Morris JAJ, et al. Dist al panc reat ec t omy f or t rauma: a mult ic ent er experienc e. J T r aum a 1991;31:1600–1606.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3146 61. Cohen AM, Crass JR. T raumat ic aort ic injuries: c urrent c onc ept s. Sem in Ult r asound CT MR 1993;14:71–84. 62. Cohen AM, Crass JR, T homas HA, et al. CT ev idenc e f or t he “ osseous pinc h” mec hanism of t raumat ic aort ic injury . AJR Am J Roent genol 1992;159:271–274. 63. Cohn SM. Pulmonary c ont usion: rev iew of t he c linic al ent it y . J T r aum a 1997;42:973–979. 64. Collins J. Chest w all t rauma. J T hor ac Im aging 2000;15:112–119. 65. Collins JC, Lev ine G, Waxman K. Oc c ult t raumat ic pneumot horax: immediat e t ube t horac ost omy v ersus expec t ant management . Am Sur g 1992;58:743–746. 66. Cook DE, Walsh JW, Vic k CW, et al. Upper abdominal t rauma: pit f alls in CT diagnosis. Radiology 1986;159:65–69. 67. Corriere JN, Sandler CM. Mec hanisms of injury : pat t erns of ext rav asat ion and management of ext raperit oneal bladder rupt ure due t o blunt t rauma. J Ur ol 1987;139:43–44. 68. Cow ley RA, T urney SZ, Hankins JR, et al. Rupt ure of t horac ic aort a c aused by blunt t rauma. A f if t een- y ear experienc e. J T hor ac Car diov asc Sur g 1990;100:652–661. 69. Cox JF , F riedman AC, Radec ki PD, et al. Periport al ly mphedema in t rauma pat ient s. AJR Am J Roent genol 1990;154:1124–1125. 70. Cox T D, Kuhn JP. CT sc an of bow el t rauma in t he pediat ric pat ient . Radiol Clin Nor t h Am 1996;34:807–818. 71. Cozac ov C, Krausz L, F reund U. Emergenc ies in delay ed diaphragmat ic herniat ion due t o blunt t rauma. Injur y 1984;15:370–371. 72. Craig MH, T alt on DS, Hauser CJ, et al. Panc reat ic injuries f rom blunt t rauma. Am Sur g 1995;61:125–128. 73. Crass JR, Cohen AM, Mot t a AO, et al. A proposed new mec hanism of t raumat ic aort ic rupt ure: t he osseous pinc h. Radiology 1990;176:645–649. 74. Croc e MA, F abian T C, Kudsk KA, et al. AAST organ injury sc ale: c orrelat ion of CT - graded liv er injuries and operat iv e f indings. J T r aum a 1991;31:806–812. 75. Croc e MA, F abian T C, Menke PG, et al. Nonoperat iv e management of blunt hepat ic t rauma is t he t reat ment of c hoic e f or hemody namic ally st able pat ient s: result s of a prospec t iv e t rial. Ann Sur g 1995;221:744–755.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3147 76. Cruz CJ, Minagi H. Large- bow el obst ruc t ion result ing f rom t raumat ic diaphragmat ic hernia: imaging f indings in f our c ases. AJR Am J Roent genol 1994;162:843–845. 77. Curt in JJ, Goodman LR, Quebbeman EJ, et al. T horac ost omy t ubes af t er ac ut e c hest injury : relat ionship bet w een loc at ion in a pleural f issure and f unc t ion. AJR Am J Roent genol 1994;163: 1339–1342. 78. Daniels DL, Maddison F E. Asc ending aort ic injury : an angiographic diagnosis. AJR Am J Roent genol 1981;136:812–813. 79. Daut eriv e AH, F lanc baum L, Cox EF . Blunt int est inal t rauma: a modern day rev iew . Ann Sur g 1985;201:198–203. 80. De Bac ker AI, De Sc hepper AM, Vaneerdew eg W, et al. Int est inal st enosis f rom mesent eric injury af t er blunt abdominal t rauma. Eur Radiol 1999;9:1429–1431. 81. Dec k AJ, Port er JR. Diagnost ic perit oneal lav age as sole indic at or of int raperit oneal bladder rupt ure: c ase report . J T r aum a 2000;49: 946–947. 82. Dec k AJ, Shav es S, T alner L, et al. Comput erized t omography c y st ography f or t he diagnosis of t raumat ic bladder rupt ure. J Ur ol 2000;164:43–46. 83. Dec k AJ, Shav es S, T alner L, et al. Current experienc e w it h c omput ed t omographic c y st ography and blunt t rauma. Wor ld J Sur g 2001;25:1592–1596. 84. Delgado Millan MA, Deballon PO. Comput ed t omography , angiography , and endosc opic ret rograde c holangiopanc reat ography in t he nonoperat iv e management of hepat ic and splenic t rauma. Wor ld J Sur g 2001;25:1397–1402. 85. Denis R, Allard M, At las H, et al. Changing t rends w it h abdominal injury in seat belt w earers. J T r aum a 1983;23:1007–1008. 86. Dennis LN, Rogers LF . Superior mediast inal w idening f rom spine f rac t ures mimic king aort ic rupt ure on c hest radiographs. AJR Am J Roent genol 1989;152:27–30. 87. Desai KM, Dorw ard IG, Minkes RK, et al. Blunt duodenal injuries in c hildren. J T r aum a 2003;54:640–645; disc ussion 645–646. 88. Dinkel HP, Danuser H, T riller J. Blunt renal t rauma: minimally inv asiv e management w it h mic roc at het er embolizat ion experienc e in nine pat ient s. Radiology 2002;223:723–730. 89. Do HM, Cronan JJ. CT appearanc e of splenic injuries managed nonoperat iv ely . AJR Am J Roent genol 1991;157:757–760.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3148 90. Dobrilov ic N, Bennet t S, Smit h C, et al. T raumat ic renal art ery dissec t ion ident if ied w it h dy namic helic al c omput ed t omography . J Vasc Sur g 2001;34:562–564. 91. Dodds WJ, T ay lor AJ, Eric kson SJ, et al. T raumat ic f rac t ure of t he panc reas: CT c harac t erist ic s. J Com put Assist T om ogr 1990;14:375–378. 92. Dondelinger RF , T rot t eur G, Ghay e B, et al. T raumat ic injuries: radiologic al hemost at ic int erv ent ion at admission. Eur Radiol 2002;12:979–993. 93. Donohue JH, Crass RA, T runkey DD. T he management of duodenal and ot her small int est inal t rauma. Wor ld J Sur g 1985;9:904–913. 94. Donohue JH, F ederle MP, Grif f it hs BG, et al. Comput ed t omography in t he diagnosis of blunt int est inal and mesent eric injuries. J T r aum a 1987;27:11–17. 95. Donov an AJ, T urrill F , Berne CJ. Injuries of t he panc reas f rom blunt t rauma. Sur g Clin Nor t h Am 1972;52:649–665. 96. Dougall AM, Paul ME, F inley RJ, et al. Chest t rauma: c urrent morbidit y and mort alit y . J T r aum a 1977;17:547–553. 97. Dow RW. My oc ardial rupt ure c aused by t rauma. Sur ger y 1982;91: 246–247. 98. Dow e MF , Shanmuganat han K, Mirv is SE, et al. CT f indings of mesent eric injury af t er blunt abdominal t rauma: implic at ions f or surgic al int erv ent ion. AJR Am J Roent genol 1997;168:425–428. 99. Dow e MF , Shanmuganat han K, Mirv is SE, et al. CT f indings of mesent eric injury af t er blunt t rauma: implic at ions f or surgic al int erv ent ion. AJR Am J Roent genol 1997;168:425–428. 100. Dow ning SW, Sperling JS, Mirv is SE, et al. Experienc e w it h spiral c omput ed t omography as t he sole diagnost ic met hod f or t raumat ic aort ic rupt ure. Ann T hor ac Sur g 2001;72:495–501; disc ussion 501–502. 101. Eger EI, Saidman LJ. Hazards of nit rous oxide anest hesia in bow el obst ruc t ion and pneumot horax. Anest hesiology 1965;26:61–66. 102. Emery KH. Lap belt iliac w ing f rac t ure: a predic t or of bow el injury in c hildren. Pediat r Radiol 2002;32:892–895. 103. Eric kson DR, Shinozaki T , Beekman E, et al. Relat ionship of art erial blood gases and pulmonary radiographs t o t he degree of pulmonary damage in experiment al pulmonary c ont usion. J T r aum a 1971;11:689–696. 104. Est rera AS, Landay MJ, Mc Clelland RN. Blunt t raumat ic rupt ure of t he right hemidiaphragm: experienc e in 12 pat ient s. Ann T hor ac Sur g 1985;39:525–530.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

21 - Computed Tomography of Thoracoabdominal Trauma3149 105. Ev ens RG. Radiology dec ision making: t he import anc e of c ost ef f ec t iv eness analy sis. AJR Am J Roent genol 1995;165:37. 106. Ev ins SC, T homason WB, Rosenblaum R. Non- operat iv e management of sev ere renal lac erat ions. J Ur ol 1980;123:247–249. 107. F aer MJ, Ly nc h RD, Lic ht enst ein JE, et al. T raumat ic splenic c y st . Radiology 1980;134:371–376. 108. F akhry SM, Brow nst ein M, Wat t s DD, et al. Relat iv ely short diagnost ic delay s ( 24 - Pediat ric Applic at ions

24 Pediatric Applications Ma rily n J. Sie ge l Bot h c omput ed t omography (CT ) and magnet ic resonanc e imaging (MRI) are import ant imaging t ec hniques in nearly ev ery part of t he pediat ric body . CT is usually t he st udy of c hoic e t o f urt her ev aluat e abnormalit ies of t he c hest , abdomen, and pelv is det ec t ed on c onv ent ional radiographic st udies or ult rasonography (US), and it is ac c ept ed as t he primary imaging t est t o ev aluat e blunt abdominal t rauma. MRI is t he primary st udy t o ev aluat e sof t t issue and paraspinal masses as w ell as joint abnormalit ies, and it is employ ed as a sec ondary t est t o assess abnormalit ies observ ed on plain radiographs or CT sc ans. T his c hapt er highlight s t he diagnost ic applic at ions of CT and MRI in a w ide v ariet y of disease proc esses of t he c hest , abdomen, pelv is, and musc uloskelet al sy st em in c hildren. General guidelines t o assist in appropriat ely selec t ing imaging examinat ions also are prov ided.

PATIENT PREPARATION/TECHNIQUE Imaging pediat ric pat ient s has sev eral inherent problems t hat are not present in adult s, in part ic ular, pat ient mot ion, small body size, and lac k of periv isc eral f at . T hese problems c an be minimized or eliminat ed by appropriat e use of sedat ion and int rav enous c ont rast medium (247).

Sedation Init ial report s suggest t hat t he use of mult idet ec t or CT has reduc ed t he f requenc y of sedat ion in inf ant s and c hildren 5 y ears of age and y ounger (116,188). Early experienc e suggest s t hat t he sedat ion rat e f or y oung c hildren undergoing mult idet ec t or CT is equal t o or less t han 5% (3). T hese st udies hav e inc luded small groups of pat ient s, so f urt her experienc e is required t o

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3555

24 - Pediatric Applications det ermine t he prec ise sedat ion rat e in a y oung pat ient populat ion. Sedat ion likely st ill w ill be required f or some unc ooperat iv e c hildren, but in general,

c hildren older t han 5 y ears of age w ill c ooperat e af t er v erbal reassuranc e and an explanat ion of t he proc edure. Sedat ion f or imaging examinat ions is nearly alw ay s c onsc ious sedat ion (70). Consc ious sedat ion is def ined as a minimally depressed lev el of c onsc iousness t hat ret ains t he pat ient 's abilit ies t o maint ain a pat ent airw ay , independent ly and c ont inuously , and respond appropriat ely t o phy sic al st imulat ion and/or v erbal c ommand. T he drugs most f requent ly used f or sedat ion are oral c hloral hy drat e and int rav enous pent obarbit al sodium. Oral c hloral hy drat e, 50 t o 100 mg/kg, w it h a maximum dosage of 2,000 mg, is t he drug of c hoic e f or c hildren y ounger t han 18 mont hs. Int rav enous pent obarbit al sodium, 6 mg/kg w it h a maximum dose of 200 mg, is adv oc at ed in c hildren older t han 18 mont hs. It is injec t ed slow ly in f rac t ions of one f ourt h t he t ot al dose and is t it rat ed against t he pat ient 's response. T his is an ef f ec t iv e f orm of sedat ion, w it h a f ailure rat e of less t han 5%. Regardless of t he c hoic e of drug, t he use of parent eral sedat ion requires t he f ac ilit y and abilit y t o resusc it at e and maint ain adequat e c ardiorespirat ory support during and af t er t he examinat ion (4,43). Pat ient s w ho are t o rec eiv e parent eral sedat ion should hav e no liquids by mout h f or 3 hours and no solid f oods f or 6 hours prior t o t heir examinat ion. Pat ient s w ho are not sedat ed but are t o rec eiv e int rav enous c ont rast medium should be NPO (not hing by mout h) f or 3 hours t o minimize t he likelihood of nausea or v omit ing w it h possible aspirat ion during a bolus injec t ion of int rav enous c ont rast medium. Af t er being sedat ed, t he inf ant or c hild is plac ed on a blanket on t he CT or MRI t able. T he arms rout inely are ext ended abov e t he head t o av oid st reak art if ac t s and t o prov ide an easily ac c essible rout e f or int rav enous injec t ion. T he upper arms c an be rest rained w it h sandbags, adhesiv e t ape, or Velc ro st raps. P.1728

Computed Tomography: Special Considerations Intravenous Contrast Material Sc anning af t er int rav enous administ rat ion of iodinat ed c ont rast mat erial is helpf ul t o c onf irm a lesion t hought t o be of v asc ular origin, or t o est ablish it s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3556

24 - Pediatric Applications relat ionship t o v asc ular st ruc t ures, in addit ion t o improv ing dif f erent iat ion bet w een normal and pat hologic parenc hy ma, espec ially in t he liv er and

kidney s. If int rav enous c ont rast mat erial is t o be administ ered, it is helpf ul t o hav e an int rav enous line in plac e w hen t he c hild arriv es in t he radiology depart ment . T his reduc es pat ient agit at ion t hat ot herw ise w ould be assoc iat ed w it h a v enipunc t ure perf ormed just prior t o administ rat ion of c ont rast mat erial. T he largest gauge c annula t hat c an be plac ed is rec ommended. T he c ont rast dose is 2 mL/kg (not t o exc eed 4 mL/kg or 125 mL). A nonionic c ont rast medium should be used. T he adv ant ages of nonionic agent s ov er ionic agent s are less disc omf ort at t he injec t ion sit e, f ew er side ef f ec t s suc h as nausea and v omit ing, and dec reased pat ient mot ion during c ont rast administ rat ion. Cont rast c an be administ ered by mec hanic al or hand injec t ion (18,240,247). T he f ormer t y pe of administ rat ion should be perf ormed if a 22- gauge or larger c annula c an be plac ed int o an ant ec ubit al v ein. T he c ont rast injec t ion rat e is det ermined by t he c aliber of t he int rav enous c at het er. Cont rast is inf used at 1.5 t o 2.0 mL per sec ond f or a 22- gauge c at het er and 2.0 t o 3.0 mL per sec ond f or a 20- gauge c at het er. T he sit e of injec t ion is c losely monit ored during t he init ial injec t ion of c ont rast t o minimize t he risk of c ont rast ext rav asat ion. A pow er injec t ion also c an be used t o administ er c ont rast media v ia a c ent ral v enous c at het er or 24- gauge c at het er if t he rat e of injec t ion is slow (1 mL per sec ond). T he c ont rast medium should be administ ered by a hand injec t ion using a bolus t ec hnique if int rav enous ac c ess is t hrough a peripheral ac c ess line or a smaller c aliber ant ec ubit al c at het er. T he c omplic at ion rat es f or manual and pow er injec t ions are similar (less t han 0.4%), prov ided t hat t he c at het er is posit ioned properly and f unc t ions w ell (117). An aut omat ed bolus t rac king t ec hnique c an be used t o monit or c ont rast enhanc ement and init iat e sc anning. T his t ec hnique allow s on- line monit oring of c ont rast enhanc ement by ac quiring v ery low mA sc ans and region of int erest measurement s at a predet ermined lev el. Onc e an arbit rary t hreshold lev el of c ont rast enhanc ement has been reac hed, diagnost ic sc anning is init iat ed.

Bowel Opacification Opac if ic at ion of t he small and large bow el is nec essary f or most examinat ions of t he abdomen, as unopac if ied bow el loops c an simulat e a mass or abnormal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3557

24 - Pediatric Applications

f luid c ollec t ion. T he exc ept ions are pat ient s w it h depressed ment al st at us w ho are at risk of aspirat ion and t hose w it h ac ut e blunt abdominal t rauma f or w hom t here may be insuf f ic ient t ime t o administ er oral c ont rast mat erial. A dilut e w at er- soluble, iodine- based oral c ont rast agent is giv en by mout h, or t hrough a nasogast ric t ube if nec essary . T he oral c ont rast agent c an be mixed w it h Kool- Aid or f ruit juic e if needed t o mask t he unpleasant t ast e. TABLE 24- 1 ORAL C ONTRAST VERSUS PATIENT AGE

Pa tie nt a ge Less t han 1 mont h 1 mont h t o 1 y ear 1 t o 5 y ears 6 t o 12 y ears 13 y ears and older

Minimum a mount giv e n a t le a st 45 min be fore Additiona l v olume giv e n sc a nning 15 min prior to sc a nning 2–3 ounc es (60–90 1–1.5 ounc es (30–45 mL) mL) 4–8 ounc es (120–240 2–4 ounc es (60–120 mL) mL) 8–16 ounc es 4–8 ounc es (120–180 (240–480 mL) mL) 16–36 ounc es 8–18 ounc es (480–1,000 mL) (180–540 mL) 36 ounc es (1,000 mL) 18 ounc es (500 mL)

T he gast roint est inal t rac t f rom t he st omac h t o t he t erminal ileum usually c an be w ell opac if ied if t he c ont rast agent is giv en in t w o v olumes, one 45 t o 60 minut es bef ore t he examinat ion and t he ot her 15 minut es prior t o sc anning. T he f irst v olume should approximat e t hat of an av erage f eeding. T he sec ond v olume should be approximat ely one half t hat of t he f irst . Appropriat e v olumes of c ont rast medium w it h respec t t o pat ient age are show n in T able 24- 1.

CT Technical Considerations Scan Delay Times T he sc an delay t ime is t he t ime bet w een t he st art of t he c ont rast injec t ion and t he st art of dat a ac quisit ion. Rout ine c hest examinat ions (i.e., sc reening f or pat hology , t umor st aging, ev aluat ion of a mediast inal mass or c ongenit al lung anomaly ) are ac quired w it h a sc an delay of 25 t o 30 sec onds. F or CT angiography , a sc an delay of 12 t o 15 sec onds is used in neonat es and inf ant s w eighing less t han 10 kg. In larger c hildren, a bolus t rac king met hod is used. A predet ermined enhanc ement lev el in t he aort a of 100 t o 120 Hounsf ield unit s (HU) is used t o t rigger t he examinat ion (240,242).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3558

24 - Pediatric Applications F or rout ine abdominal and pelv ic examinat ions (i.e., ev aluat ion of abdominal t umor, t rauma, or absc ess), t he sc an delay t ime is 55 t o 60 sec onds. CT angiography is used in t he ev aluat ion of hepat ic masses and f or preoperat iv e v asc ular mapping. T he t ime delay f or an art erial phase ac quisit ion is 12 t o 15 sec onds in inf ant s and small c hildren w eighing less t han 10 kg. In larger c hildren and adolesc ent s, P.1729 t he t ime delay f or art erial phase imaging is 20 sec onds. T he v enous phase is init iat ed 55 t o 60 sec onds af t er t he st art of c ont rast administ rat ion. TABLE 24- 2 MILLIAMPERAGE SETTINGS We ight (kg) 45

C he st C T mAs 40 50 60 70 80 100 or >

Abdome n C T mAs 50 60 70 90 100 120 or >

Technical Parameters St rat egies t hat minimize radiat ion dose are mandat ory f or CT examinat ions in c hildren (53,86,190,259). A v ariet y of paramet ers c an af f ec t t he amount of radiat ion f rom CT , inc luding t ube c urrent , kilov olt age, t able speed, and det ec t or c ollimat ion. T he c urrent (in mA) f or pediat ric CT examinat ions needs t o be t he low est possible t hat maint ains image qualit y . General guidelines f or t ube c urrent based on pat ient w eight are show n in T able 24- 2. Kilov olt age is anot her f ac t or t hat af f ec t s sc an qualit y and radiat ion dose. A kVp of 80 should be c onsidered f or pat ient s w eighing less t han 50 kg. In larger pat ient s, a higher kVp (100 t o 120) should be used t o c ompensat e f or t he higher noise (224). F or opt imal examinat ion of c hildren, CT examinat ions should be perf ormed w it h sc an t imes of 1 sec ond or less. Det ec t or c ollimat ion and pit c h v ary depending on t he t y pe of sc anner used. F or a f our- row det ec t or sc anner, a 2.5- mm c ollimat ion w it h a pit c h of 1.5 t o 2.0 is adequat e f or rout ine sc anning. F or a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3559

24 - Pediatric Applications 16- row det ec t or, 1.25 t o 1.5 mm c ollimat ion w it h a pit c h of 1.0 t o 1.5

suf f ic es. F or a 64- row det ec t or, 0.6 t o 1.25- mm c ollimat ion and a pit c h of 1.0 t o 1.5 suf f ic es (see Prot oc ols 1, 2, 3, 4, 5 at t he end of t his c hapt er). CT examinat ions are perf ormed w it h breat h- holding at suspended inspirat ion in c ooperat iv e pat ient s, usually c hildren ov er 5 t o 6 y ears of age. Sc ans are obt ained during quiet respirat ion in c hildren w ho are unable t o c ooperat e w it h breat h- holding inst ruc t ions and in pat ient s w ho are sedat ed.

Magnetic Resonance Imaging: Technical Considerations Imaging Parameters Lesion det ec t abilit y is dependent on t he signal- t o- noise (S/N) rat io, spat ial resolut ion, and c ont rast resolut ion. T hese paramet ers v ary w it h t he size of t he rec eiv er c oil, slic e t hic kness, f ield of v iew (F OV), mat rix size, and number of ac quisit ions. F or opt imal S/N rat io and spat ial resolut ion, MRI examinat ions should be perf ormed w it h t he smallest c oil t hat f it s t ight ly around t he body part being st udied (5,12,195). A head c oil usually is adequat e in inf ant s and small c hildren, w hereas a w hole- body or phased- array surf ac e c oil is needed f or larger c hildren and adolesc ent s. Surf ac e c oils c an be usef ul in t he ev aluat ion of superf ic ial st ruc t ures, suc h as t he spine, but t he drop- of f in signal st rengt h w it h inc reasing dist anc e f rom t he c ent er of t he c oil limit s t he v alue of t hese c oils in t he ev aluat ion of deeper abdominal st ruc t ures. Slic e t hic kness v aries w it h pat ient size and t he area of int erest . T hinner slic es (3 t o 4 mm) are used in t he ev aluat ion of small lesions and t hrough areas of maximum int erest , w hereas t hic ker slic es (6 t o 8 mm) suf f ic e f or a general surv ey of t he c hest and abdomen and f or larger lesions. T he F OV c an hav e a square or rec t angular shape. A square shape is used w hen t he body part being examined f ills t he F OV. An asy mmet ric rec t angular F OV is ideal f or body part s t hat are narrow in one direc t ion, suc h as t he abdomen in a t hin pat ient . One or t w o signal ac quisit ions generally are used in pediat ric MRI examinat ions t o short en imaging t ime.

Pulse Sequences

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3560

24 - Pediatric Applications Spin-Echo Sequence

T 1- w eight ed sequenc es [short repet it ion t ime (T R), short ec ho t ime (T E)] are obt ained in v irt ually all pat ient s bec ause t hey prov ide exc ellent c ont rast bet w een sof t t issue st ruc t ures and f at and t hus help in t issue c harac t erizat ion (i.e., f luid, f at , or blood). F at - suppressed T 1- w eight ed images are usef ul t o improv e c onspic uit y of diseased t issues. T 2- w eight ed sequenc es (long T R, long T E) are used in most examinat ions of t he c hest (exc luding heart and great v essels), abdomen, and musc uloskelet al sy st em. T hey prov ide exc ellent c ont rast bet w een t umor and adjac ent sof t t issues and are usef ul f or t issue c harac t erizat ion. T he T 2- w eight ed sequenc es c an be ac quired w it h c onv ent ional or ec ho- t rain (f ast /t urbo) t ec hniques. Ec ho- t rain spin- ec ho sequenc es are usef ul w hen dec reased imaging t ime is desired, alt hough t hese images may lead t o a dec rease in c ont rast and c an at t imes render liv er lesions imperc ept ible. T o inc rease lesion c onspic uit y , f at suppression t ec hniques c an be used in c onjunc t ion w it h T 2- w eight ed ec hot rain sequenc es. Most lesions hav e low signal int ensit y on T 1- w eight ed images and high signal int ensit y on T 2- w eight ed images. T he T 1 signal c an inc rease if t he lesion c ont ains f at , blood, prot einac eous f luid, or c art ilage. Mineralizat ion and gadolinium c helat e enhanc ement also result in high T 1 signal int ensit y . A low T 2 signal int ensit y is seen w it h mineralizat ion, hemosiderin and ot her blood produc t s, iron oxide, and f ibrosis.

Other Magnetic Resonance Imaging Techniques F at - suppressed sequenc es are usef ul t o inc rease c ont rast bet w een normal and pat hologic t issues on T 2- w eight ed images. T w o basic met hods of f at suppression are w idely P.1730 av ailable: short t au inv ersion rec ov ery (ST IR) and radiof requenc y presat urat ion of t he lipid peak (f at sat urat ion). Signal f rom f at is nulled on ST IR and f at - sat urat ed images, w hereas most pat hologic lesions, w it h inc reased f ree w at er and prolonged T 1 and T 2 v alues, are bright on t he f at suppressed sequenc es. Gradient - ec ho (GRE) t ime of f light images are usef ul f or det ec t ing f low ing blood. F low ing blood t y pic ally appears bright on GRE images (214). By c omparison, f low ing blood appears as a f low v oid or dec reased signal w it hin

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3561

24 - Pediatric Applications t he v essel lumen on spin ec ho sequenc es. GRE imaging is most ef f ec t iv e in c ooperat iv e c hildren w ho c an suspend respirat ion, but it c an be used in c hildren of any age. T he ev aluat ion of blood f low w it h t he GRE sequenc e requires t he use of t ec hnic al paramet ers t hat are t ailored f or v asc ular imaging. Chemic al shif t imaging is a met hod t hat is helpf ul t o det ec t and c harac t erize lesions suspec t ed of c ont aining mic rosc opic f at . T his t ec hnique uses GRE images obt ained in phase and out of phase t o exploit dif f erenc es in prec essional f requenc ies of f at and w at er. T he presenc e of f at and w at er w it hin a v oxel result s in phase c anc ellat ion and dec reased signal int ensit y on out - of - phase images. T he short est possible T E should be used f or out - of phase imaging t o reduc e T 2* ef f ec t s.

Contrast-Enhanced Imaging Gadolinium, a paramagnet ic met al ion, is most f requent ly used in MRI f or c ont rast enhanc ement (5,12,195). When used as an MR c ont rast agent , gadolinium is c helat ed w it h anot her subst anc e, suc h as dimeglumine or diet hy lenet riamine pent a- ac et ic ac id. Gadolinium c helat es are ext rac ellular c ont rast agent s t hat c ause T 1 short ening of t issues in w hic h t he agent is t aken up. T he usual dose is 0.1 mmol/kg. Gadolinium- enhanc ed T 1- w eight ed imaging w it h f at suppression is used in t he ev aluat ion of t umors t o improv e c ont rast bet w een normal and pat hologic t issue and t o help in lesion c harac t erizat ion. F or gadolinium- enhanc ed MR angiography , a t hreedimensional (3D) spoiled gradient - ec ho is used and t he dat a are obt ained in a v olume, t y pic ally during suspended respirat ion (88,273). Single- shot ec ho t rain imaging is t he sequenc e used f or MR c holangiopanc reat ography (170) and urography (25). T he single- shot f ast spin ec ho uses long ec ho t rain lengt hs and half F ourier imaging t o prov ide f ast images.

Optimizing Image Quality As a result of t he relat iv ely long t ime required t o perf orm abdominal MRI in c hildren, gross v olunt ary mot ion or phy siologic mot ion, suc h as respirat ion and blood f low , may produc e art if ac t s t hat degrade t he MR image. Volunt ary mot ion c an be minimized or eliminat ed w it h t he use of sedat ion, w hereas phy siologic mot ion and it s result ant art if ac t s—ghost ing and blurring—c an be suppressed by adjust ing t ec hnic al paramet ers (169). New er t ec hniques,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3562

24 - Pediatric Applications suc h as respirat ory t riggering using an abdominal belt or by monit oring diaphragmat ic mot ion, c an be used t o reduc e breat hing art if ac t . GRE, f ast

spin- ec ho, and single- shot f ast spin- ec ho sequenc es, and signal av eraging, or inc reasing t he number of exc it at ions in t he MR examinat ion, are simple met hods t o reduc e respirat ory mot ion art if ac t s. Spat ial presat urat ion, an addit ional t ec hnique f or mot ion suppression, uses selec t iv e radiof requenc y pulses t o sat urat e spins t hat are out side of t he area of int erest being imaged. T hus, blood f low ing int o t he imaged sec t ion has lit t le signal and c onsequent ly produc es lit t le or no art if ac t . Presat urat ion also c an eliminat e abdominal w all mot ion art if ac t ev en it if is in t he same c ross- sec t ional image. Elec t roc ardiographic (ECG) gat ing reduc es mot ion unsharpness and is used in MRI examinat ions of t he t horax. T his t ec hnique ent ails an inc rease in sc an t ime, but it markedly improv es t he image qualit y . Imaging is t riggered t o t he R- w av e of t he ECG, w it h dat a ac quisit ion t aking plac e during diast ole.

CHEST Mediastinum Cross- sec t ional CT and MR images are part ic ularly helpf ul in det ec t ing or c larif y ing abnormalit ies in t he mediast inum, c hest w all, and peridiaphragmat ic and subpleural regions of t he lung. T he inf ormat ion prov ided by t hese t ec hniques c an direc t ly af f ec t t he t reat ment or aid in det ermining t he prognosis of a pat ient . Indic at ions f or CT and MRI of t he mediast inum inc lude (a) c harac t erizat ion of mediast inal w idening or ev aluat ion of a mass suspec t ed or det ec t ed on c hest radiography ; (b) det erminat ion of t he ext ent of a prov ed mediast inal t umor; (c ) det ec t ion of mediast inal inv olv ement in c hildren w ho hav e an underly ing disease t hat may be assoc iat ed w it h a mediast inal mass but w ho hav e a normal c hest radiograph; and (d) assessment of t he response of a mediast inal mass t o t herapy .

Normal Anatomy Thymus In t he pediat ric populat ion, t he normal t hy mus is seen in v irt ually ev ery pat ient . In indiv iduals under age 20, t here are w ide v ariat ions in size and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3563

24 - Pediatric Applications shape of t he normal t hy mus. Rec ognit ion of t he v arious appearanc es of t he normal t hy mus is import ant if errors in diagnosis are t o be av oided (217,228,237). In pat ient s y ounger t han 5 y ears, t he t hy mus usually has a

quadrilat eral shape w it h c onv ex or st raight lat eral margins (F ig. 24- 1). Lat er in t he f irst dec ade, t he t hy mus is t riangular or arrow head- shaped w it h st raight or c onc av e margins, and by 15 y ears of age, it is t riangular in nearly all indiv iduals (F ig. 24- 2). In general, in t he f irst t w o dec ades of lif e, t he t hy mus abut s t he st ernum, separat ing t he t w o lungs. A dist inc t ant erior junc t ion line P.1731 bet w een t he lungs is usually not seen unt il t he t hird dec ade of lif e.

F igure 24- 1 Normal c omput ed t omography appearanc e of t hy mus, 6- mont hold boy . T he t hy mus (T ) is quadrilat eral in shape w it h slight ly c onv ex lat eral borders and a w ide ret rost ernal c omponent . T he densit y of t he t hy mus is equal t o t hat of c hest w all musc ulat ure. A nasogast ric t ube is present in t he esophagus. T here is minimal right upper lobe at elec t asis.

T he t hy mus in prepubert al c hildren and most adolesc ent s is homogeneous, w it h an at t enuat ion v alue equal t o t hat of c hest w all musc ulat ure. In approximat ely 30% of adolesc ent s, t he t hy mus is het erogeneous, c ont aining low - densit y areas of f at deposit ion. T hy mic lobar w idt h (largest dimension parallel t o t he long axis of t he lobe) show s lit t le c hange w it h age. T hy mic lobar t hic kness (t he largest dimension perpendic ular t o t he long axis of t he lobe) c orrelat es inv ersely w it h adv anc ing age, dec reasing f rom 1.50 Г— 0.46 (mean Г— st andard dev iat ion) c m f or t he 0 t o 10 y ear age group t o 1.05 Г— 0.36 c m f or pat ient s bet w een 10 and 20 y ears of age. F or inf ilt rat iv e diseases

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3564

24 - Pediatric Applications of t he t hy mus, inc reased t hic kness is a f airly sensit iv e indic at or of an abnormalit y .

Signal int ensit y of t he t hy mus on MR images also v aries w it h pat ient age. T he signal int ensit y of t he prepubert al t hy mus is slight ly great er t han t hat of musc le on T 1- w eight ed images, slight ly less t han or equal t o t hat of f at on T 2- w eight ed images, and great er t han t hat of f at on f at - suppressed T 2w eight ed images (F ig. 24- 3). Af t er pubert y , t he signal int ensit y on T 1w eight ed images inc reases, ref lec t ing f at t y replac ement (F ig. 24- 4). Measurement s of t hy mic t hic kness are slight ly great er on MRI t han on CT , probably ref lec t ing t he low er lung v olumes on MR images (217). MR images are obt ained during quiet respirat ion, w hereas CT images generally are obt ained in suspended or f ull inspirat ion. T his dif f erenc e produc es some f lat t ening of t he t hy mus in t he c ranioc audal dimension on MRI, w hic h inc reases t hic kness. Oc c asionally , t he t hy mus ext ends eit her c ranially abov e t he brac hioc ephalic v essels or int o t he post erior t horax. T he CT or MRI f indings of t he abnormally posit ioned t hy mus are: it s direc t c ont inuit y w it h t he t hy mic t issue in t he ant erior mediast inum, an at t enuat ion v alue or signal int ensit y similar t o t hat of normal t hy mic t issue, and t he lac k of c ompression of adjac ent mediast inal v essels or t he t rac heobronc hial t ree.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3565

24 - Pediatric Applications

F igure 24- 2 Normal c omput ed t omography appearanc e of t hy mus, 10- y ear- old boy . T he t hy mus (T ) has assumed a t riangular shape, but it st ill abut s t he st ernum and has a densit y equal t o t hat of c hest w all musc ulat ure.

Lymph Nodes Mediast inal ly mph nodes generally are not seen on CT or MRI in c hildren prior t o pubert y , and t heir presenc e should be c onsidered abnormal (237). In adolesc ent s, small normal nodes (not exc eeding 1 c m in w idest dimension) oc c asionally c an be ident if ied. Nodes are of sof t t issue at t enuat ion on CT and hav e signal int ensit y bet w een t hose of musc le and f at on bot h T 1- and T 2w eight ed images.

Azygoesophageal Recess T he c onf igurat ion of t he azy goesophageal rec ess v aries w it h pat ient age. T he c ont our of t he rec ess is c onv ex lat erally in c hildren under 6 y ears of age, st raight in c hildren bet w een 5 and 12 y ears of age, and c onc av e in adolesc ent s and y oung adult s (167) (F ig. 24- 5). Rec ognit ion of t he normal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3566

24 - Pediatric Applications dext roc onv ex appearanc e in y oung c hildren is import ant so t hat it is not mist aken f or ly mphadenopat hy .

F igure 24- 3 Normal magnet ic resonanc e imaging (MRI) appearanc e of t he t hy mus, 2- y ear- old boy . A: T 1- w eight ed t ransaxial MR image show s a quadrilat eral- shaped t hy mus (T ) ant erior t o t he superior v ena c av a (S) and aort ic arc h (A). T he signal int ensit y is equal t o t hat of t he c hest w all musc ulat ure but is less t han t hat of subc ut aneous f at . B: F at - sat urat ed T 2w eight ed t ransaxial MRI. T he signal int ensit y of t he t hy mus (T ) is great er t han t hat of subc ut aneous f at .

F igure 24- 4 Normal magnet ic resonanc e (MR) imaging appearanc e of t he t hy mus, 15- y ear- old boy . T 1- w eight ed axial MR image show s a high signal int ensit y t hy mus (T ), indic at ing t he presenc e of f at t y replac ement .

P.1732

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3567

24 - Pediatric Applications Mediastinal Pathology A w idened mediast inum in inf ant s and c hildren of t en is t he result of a mass, usually a ly mphoma, neurogenic t umor, t erat oma, or c y st of f oregut origin. Abundant mediast inal f at , aneury sms, or t ort uosit y of t he mediast inal v essels are rare in c hildren. CT and MRI hav e t he c apabilit y of dif f erent iat ing among lesions c omposed predominant ly of f at , w at er, or sof t t issues and, t heref ore, c an prov ide a more def init iv e diagnosis t han c an c onv ent ional radiographic t ec hniques (161,166,237). F at - c ont aining masses in c hildren usually are t erat omas. Rarely , t hey represent t hy molipomas or herniat ion of oment al f at t hrough t he f oramen of

Morgagni. Lesions t hat c an present w it h at t enuat ion v alues near t hat of w at er inc lude peric ardial c y st s, t hy mic c y st s, ly mphangiomas, and duplic at ion c y st s of f oregut origin. Rarely , bronc hogenic c y st s or duplic at ion c y st s hav e a densit y equal t o t hat of sof t t issue, bec ause t hey c ont ain t hic k v isc id c ont ent s, rat her t han simple serous f luid. Vasc ular c auses of mediast inal w idening, suc h as aort ic aneury sm or a c ongenit al anomaly of t he t horac ic v asc ular sy st em, also c an be ident if ied w it h c onf idenc e on CT sc ans or on MRI. CT c an be v aluable in det ermining t he ext ent or origin of most sof t t issue at t enuat ion mediast inal masses, but a spec if ic pat hologic diagnosis generally is not possible. Det ermining t he loc at ion of t he mass in t he mediast inum, how ev er, c an narrow t he dif f erent ial diagnosis.

Anterior Mediastinal Masses: Soft Tissue Attenuation Lymphoma Ly mphoma is t he most c ommon c ause of an ant erior mediast inal mass of sof t t issue at t enuat ion in c hildren, w it h Hodgkin disease oc c urring t hree t o f our t imes more f requent ly t han non- Hodgkin ly mphoma (102,213). Approximat ely 65% of pediat ric pat ient s w it h Hodgkin disease hav e int rat horac ic inv olv ement at c linic al present at ion, and 90% of t he c hest inv olv ement is mediast inal. In c ont radist inc t ion, about 40% of pediat ric pat ient s w it h non- Hodgkin ly mphoma hav e c hest disease at diagnosis, and only 50% of t his disease inv olv es t he mediast inum. CT play s an import ant role in t he ident if ic at ion and st aging of

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3568

24 - Pediatric Applications disease, t he planning of t reat ment , and t he f ollow - up ev aluat ion of pat ient s w it h ly mphoma (28,89,149). Ly mphomat ous masses in Hodgkin disease are most c ommon in t he ant erior mediast inum and ref lec t ly mphadenopat hy P.1733 or inf ilt rat ion and enlargement of t he t hy mus. T he enlarged t hy mus has a

quadrilat eral shape w it h c onv ex, lobular lat eral borders (F ig. 24- 6). On CT , t he at t enuat ion of t he ly mphomat ous organ is equal t o t hat of sof t t issue (20,89,217,228). T he MR signal int ensit y is slight ly great er t han t hat of musc le on T 1- w eight ed pulse sequenc es and similar t o or slight ly great er t han t hat of f at on T 2- w eight ed pulse sequenc es (217) (F ig. 24- 7). Calc if ic at ions or c y st ic areas result ing f rom isc hemic nec rosis c onsequent t o rapid t umor grow t h c an be seen w it hin t he t umor (137) (F ig. 24- 8). Addit ional f indings inc lude mediast inal or hilar ly mph node enlargement , airw ay narrow ing, and c ompression of v asc ular st ruc t ures.

F igure 24- 5 Azy goesophageal rec ess. A: In t his 5- y ear- old boy , t he rec ess (ar r ow ) has a c onv ex lat eral shape, result ing f rom int rusion of t he esophagus int o t he rec ess. B: A 15- y ear- old boy has a c onc av e azy goesophageal rec ess (ar r ow ).

Int rat horac ic ly mphadenopat hy f rom ly mphoma has v aried appearanc es, ranging f rom mildly enlarged nodes in a single area t o large c onglomerat e sof t t issue masses in mult iple regions. T y pic ally , t he enlarged nodes hav e w elldef ined margins and show lit t le enhanc ement af t er int rav enous administ rat ion of c ont rast medium (F ig. 24- 9). Hodgkin disease usually c auses enlargement of t he t hy mus or ant erior mediast inal nodes, w hereas non- Hodgkin ly mphoma predominant ly af f ec t s middle mediast inal ly mph nodes.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3569

24 - Pediatric Applications Suc c essf ully t reat ed ly mphomas usually dec rease in size, but residual

mediast inal masses may remain on serial CT examinat ions (28,149). Dif f erent ial diagnost ic c onsiderat ions in t hese c ases inc lude f ibrosis v ersus persist ent or rec urrent ly mphoma. Serial CT examinat ions c an usually dist inguish bet w een t hese t w o c ondit ions. In general, masses result ing f ibrosis remain st able or dec rease in size, w hereas t umor is likely t o inc rease in size. MR, gallium- 67 sc int igraphy , and posit ron emission t omography (PET ) w it h 2[F - 18]- f luoro- 2- deoxy - D- gluc ose (F DG) hav e been used t o assess t reat ment response in t he inst anc es in w hic h CT is not diagnost ic (69,181,263). F ibrosis has low signal int ensit y (similar t o t hat of musc le) on T 1- and T 2- w eighed and f at - suppressed sequenc es, w hereas ac t iv e neoplasm has high signal int ensit y on T 2- w eight ed sequenc es. How ev er, inc reased signal int ensit y is not spec if ic f or t umor and it also may be assoc iat ed w it h inf ec t ion, hemorrhage, ac ut e radiat ion pneumonit is, nec rosis, and immat ure f ibrot ic t issue early in t he post t reat ment c ourse. Gallium and F DG ac c umulat e in v iable t umor, but not in f ibrot ic t issue.

Thymic Hyperplasia T hy mic hy perplasia is anot her c ause of dif f use t hy mic enlargement . In c hildhood, t hy mic hy perplasia is most of t en “ rebound” hy perplasia assoc iat ed w it h c hemot herapy , part ic ularly t herapy w it h c ort ic ost eroids. Rebound hy perplasia may be observ ed during t he c ourse of c hemot herapy or af t er t he c omplet ion of t herapy . T he mec hanism of hy perplasia in t hese c ases is believ ed t o be init ial deplet ion of ly mphoc y t es f rom t he c ort ic al port ion of t he gland bec ause of high serum lev els of gluc oc ort ic oids, f ollow ed by repopulat ion of t he c ort ic al ly mphoc y t es w hen t he c ort isone lev els ret urn t o normal. Rare c auses of hy perplasia inc lude my ast henia grav is, red c ell aplasia, and hy pert hy roidism. On CT and MRI, hy perplasia appears as dif f use enlargement of t he t hy mus w it h preserv at ion of t he normal t riangular shape (20,228,237) (F ig. 24- 10). T he at t enuat ion v alue and t he signal int ensit y of t he hy perplast ic t hy mus on spinec ho sequenc es are similar t o t hose of t he normal organ and also t umor. T he absenc e of ot her ac t iv e disease and a gradual dec rease in size of t he t hy mus on serial CT sc ans or MRI support s t he diagnosis of rebound hy perplasia as t he c ause of t hy mic enlargement . Limit ed experienc e suggest s t hat c hemic al shif t MRI also may be usef ul in t he diagnosis of t hy mic hy perplasia and in it s dif f erent iat ion

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3570

24 - Pediatric Applications P.1734

f rom neoplast ic proc esses. Normal and hy perplast ic t hy mic t issues show low er int ensit y on opposed- phase GRE images t han on in- phase imaging. T he neoplast ic t hy mus rev eals no signal c hange bet w een in- phase and opposedphase c hemic al shif t MR images (270).

F igure 24- 6 T hy mic Hodgkin disease, nodular sc lerosing t y pe, 11- y ear- old girl. Cont rast - enhanc ed c omput ed t omography image show s a markedly enlarged t hy mus w it h a lobulat ed c ont our. T he inf ilt rat ed t hy mus displac es t he asc ending aort a (AA) and superior v ena c av a (S) post eriorly . Not e t he c ompressiv e ef f ec t s on t he c av a and t rac hea.

F igure 24- 7 T hy mic Hodgkin disease, nodular sc lerosing t y pe, 15- y ear- old girl. A: Coronal short t au inv ersion rec ov ery magnet ic resonanc e image show s t hy mic inf ilt rat ion (T ). T he t hy mus is het erogeneous and has a signal int ensit y

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3571

24 - Pediatric Applications slight ly great er t han t hat of subc ut aneous f at . T umor is also present in bot h suprac lav ic ular areas (ar r ow s).

Thymoma T hy momas ac c ount f or less t han 5% of all mediast inal t umors in c hildren. Nearly all t hy momas are benign and oc c ur sporadic ally , but t hey c an be f ound in assoc iat ion w it h my ast henia grav is, red c ell aplasia, or hy pogammaglobulinemia. Benign t hy momas appear as w ell- def ined, round or ov al masses bulging t he lat eral t hy mic margin. On CT , t hey are of int ermediat e sof t t issue densit y , but somet imes t hey c ont ain c alc if ic at ions or low er densit y areas of nec rosis (228,237). On T 1- w eight ed MR images, t hy momas hav e signal int ensit y similar t o t hat of musc le; t he signal int ensit y inc reases on T 2w eight ed images, approac hing t hat of f at (217). Approximat ely 10% t o 15% of t hy momas are inv asiv e (i.e., malignant ). T he CT and MRI appearanc e of inv asiv e t hy moma is t hat of an ant erior mediast inal P.1735 mass assoc iat ed w it h mediast inal or c hest w all ext ension or met ast at ic implant s along mediast inal, pleural, or peric ardial surf ac es, usually limit ed t o one side of t he t horac ic c av it y .

F igure 24- 8 T hy mic Hodgkin disease, nodular sc lerosing t y pe w it h c y st ic c hanges, 15- y ear- old girl. Cont rast - enhanc ed c omput ed t omography sc an show s an enlarged t hy mus w it h c y st ic c omponent s, result ing f rom nec rosis, in t he lef t lobe. Mult iple enlarged ly mph nodes are not ed in t he ant erior mediast inum and subc arinal (ar r ow ) area. T here is also a small right pleural ef f usion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3572

24 - Pediatric Applications

F igure 24- 9 Ly mphadenopat hy , non- Hodgkin disease. Comput ed t omography sc an show s enlarged nodes in t he hilar and subc arinal (ar r ow ) areas. T he ant erior mediast inum is normal.

F igure 24- 10 Rebound t hy mic hy perplasia, 4- y ear- old boy rec eiv ing c hemot herapy f or Wilms t umor. A: Comput ed t omography (CT ) image of t he c hest at t he t ime of diagnosis show s a normal t hy mus (ar r ow ). B: CT image 3 mont h af t er t he st art of c hemot herapy show s enlargement of bot h lobes of t he t hy mus. T he pat ient w as c linic ally doing w ell. A f ollow - up CT st udy 6 mont hs lat er show ed spont aneous reduc t ion in t he size of t he t hy mus.

Miscellaneous Lesions

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3573

24 - Pediatric Applications Ot her dif f erent ial diagnost ic c onsiderat ions f or dif f use t hy mic enlargement inc lude leukemia, Langerhans c ell hist ioc y t osis, and hist oplasmosis. Diagnosis requires t issue sampling. T hy roid abnormalit ies are a rare c ause of an ant erior mediast inal mass in c hildren. In c hildhood, an int rat horac ic t hy roid gland is more likely t o represent t rue ec t opic t hy roid t issue rat her t han subst ernal ext ension of a c erv ic al t hy roid gland. T he CT f eat ures of int rat horac ic t hy roid are a w elldef ined, int ensely enhanc ing sof t t issue mass ant erior t o t he t rac hea.

Anterior Mediastinal Masses: Fat Attenuation Germ Cell Tumors Germ c ell t umors are t he sec ond most c ommon c ause of an ant erior mediast inal mass in c hildren and t he most c ommon c ause of a f at - c ont aining lesion. T hey are deriv ed f rom one or more of t he t hree embry onic germ c ell lay ers and usually arise in t he t hy mus. Approximat ely 90% are benign and hist ologic ally are eit her dermoid c y st s (c ont aining only ec t odermal element s) or t erat omas (c ont aining t issue f rom all t hree germinal lay ers). On CT , bot h lesions are w ell def ined, t hic k- w alled c y st ic masses c ont aining a v ariable admixt ure of t issues: w at er, c alc ium, f at , and sof t t issue (193,206) (F ig. 2411). A f at –f luid lev el and amorphous bone or t eet h oc c asionally c an be seen w it hin t hese t umors. On MRI, germ c ell t umors are het erogeneous masses w it h v ariable signal int ensit ies depending on t he relat iv e amount s of f luid and f at (217). F luid c omponent s usually hav e a signal int ensit y less t han or equal t o t hat of musc le on T 1- w eight ed images. T he signal int ensit y c an be great er t han t hat of musc le if t he c ont ent s c ont ain blood or prot einac eous mat erial. T he signal int ensit y of f luid usually is hy perint ense t o f at on T 2- w eight ed images. F at c omponent s hav e high signal int ensit y on bot h P.1736 T 1- and T 2- w eight ed images. Calc if ic at ion and bone hav e low signal int ensit y on all imaging sequenc es.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3574

24 - Pediatric Applications

F igure 24- 11 Benign t erat oma. A large, w ell- c irc umsc ribed, het erogeneous mass c ont aining low - densit y f luid, c alc if ic at ions, and f at oc c upies most of t he lef t hemit horax. T he mass displac es but does not inv ade v asc ular st ruc t ures. Pat hologic examinat ion show ed a benign c y st ic t erat oma, w hic h c ont ained sebac eous f luid, a small amount of f at , and embry onic t eet h.

F igure 24- 12 T erat oc arc inoma. A large ant erior mediast inal, sof t t issue mass, c ont aining c alc if ic at ions and some low - densit y areas represent ing nec rosis, displac es t he main pulmonary t o t he right and post eriorly .

A malignant t erat oma generally appears on CT and MRI as a poorly def ined, sof t t issue mass, somet imes c ont aining c alc if ic at ion and f at . Loc al inf ilt rat ion int o t he adjac ent mediast inum w it h enc asement or inv asion of mediast inal v essels or airw ay s also is f requent . Ot her malignant germ c ell t umors arising in

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3575

24 - Pediatric Applications t he ant erior mediast inum are seminoma, embry onal c ell c arc inoma, c horioc arc inoma, and endodermal sinus t umor. T hese t umors t y pic ally are

het erogeneous, sof t t issue densit y masses c ont aining some low - densit y areas of nec rosis (F ig. 24- 12). Rarely , t hey c ont ain c alc if ic at ions (206).

Thymolipoma T hy molipoma is an inf requent c ause of an int rat hy mic t umor. Pat hologic ally , t he t umor c ont ains mat ure f at and st rands of t hy mic t issue. Most c ases in t he pediat ric populat ion oc c ur in t he sec ond dec ade and are disc ov ered inc ident ally on plain radiographs. T he t umor of t en is large, ext ending c audally t o t he diaphragm, and may mimic c ardiomegaly or a c ardiophrenic mass. On CT and MRI, it appears as a het erogeneous mass c ont aining f at and some sof t t issue element s. T hy molipoma does not c ompress or inv ade adjac ent st ruc t ures (204).

Anterior Mediastinal Masses: Fluid Attenuation Thymic Cysts T hy mic c y st s usually are c ongenit al lesions result ing f rom persist enc e of t he t hy mophary ngeal duc t , but t hey c an oc c ur af t er t horac ot omy . T y pic ally , t hey are t hin- w alled, homogeneous masses of near w at er densit y on CT (F ig. 2413), low signal int ensit y on T 1- w eight ed MR images, and high signal int ensit y on T 2- w eight ed sequenc es. T he at t enuat ion v alue or t he signal int ensit y on T 1- w eight ed images may be higher t han t hat of simple c y st s w hen t he c y st 's c ont ent s are prot einac eous or hemorrhagic rat her t han serous. Mult iple t hy mic c y st s hav e also been desc ribed in c hildren w it h HIV inf ec t ion and Langerhans c ell hist ioc y t osis (10,142).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3576

24 - Pediatric Applications

F igure 24- 13 T hy mic c y st . Cont rast - enhanc ed c omput ed t omography demonst rat es replac ement of t he t hy mus by a homogeneous, w at erat t enuat ion mass (M).

F igure 24- 14 Cy st ic hy groma, 6- mont h- old girl. Comput ed t omography sc an t hrough t he superior mediast inum show s a low - densit y mass inf ilt rat ing t he superior mediast inum. T he t umor enc ases t he mediast inal v essels.

Cystic Hygroma Cy st ic hy gromas (ly mphangiomas) are dev elopment al t umors of t he ly mphat ic sy st em t hat oc c ur in t he ant erosuperior mediast inum and are almost alw ay s inf erior ext ensions of c erv ic al hy gromas. On CT , t hey appear as nonenhanc ing,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3577

24 - Pediatric Applications

t hin- w alled, mult iloc ulat ed masses w it h near- w at er at t enuat ion v alue (F ig. 2414). T he presenc e of P.1737 c ont rast enhanc ement of t he w all or int ernal sept at ions suggest s superimposed inf ec t ion or a hemangiomat ous c omponent . On MRI, c y st ic hy groma has signal int ensit y equal t o or slight ly less t han t hat of musc le on T 1- w eight ed images and great er t han t hat of f at on T 2- w eight ed images (216) (F ig. 24- 15). T he surrounding f asc ial planes are oblit erat ed if t he t umor inf ilt rat es t he adjac ent sof t t issues. Hemorrhage c an c ause a sudden inc rease in t umor size and c an inc rease t he CT at t enuat ion v alue or t he signal int ensit y on T 1- w eight ed MR images (216). Oc c asionally , marked dilat at ion of adjac ent v eins is not ed (113).

F igure 24- 15 Cy st ic hy groma, new born girl. T 2- w eight ed c oronal magnet ic resonanc e image show s a het erogeneous high signal int ensit y mass inf ilt rat ing t he superior mediast inum and right nec k. T he t umor ext ends int o t he right t hy mic lobe.

Middle Mediastinal Masses T he f requent c auses of middle mediast inal masses are ly mph node enlargement and c ongenit al f oregut c y st s.

Lymphadenopathy

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3578

24 - Pediatric Applications Ly mph node enlargement , as a c ause of a middle mediast inal mass, is usually

c aused by ly mphoma or granulomat ous disease. On CT , adenopat hy c an appear as disc ret e, round sof t t issue masses, or as a single sof t t issue mass w it h poorly def ined margins. Calc if ic at ion w it hin ly mph nodes suggest s old granulomat ous disease, suc h as hist oplasmosis or t uberc ulosis. On T 1w eight ed MR images, ly mph nodes inv olv ed by inf ec t ion or t umor hav e a signal int ensit y similar t o or slight ly great er t han t hat of musc le. On T 2- w eight ed MR images, t he signal int ensit y is high, similar t o t hat of f at . Most ly mph nodes are homogeneous on MRI, but t hey c an appear het erogeneous if t hey c ont ain c alc if ic at ion or nec rosis. Neit her CT nor MRI is able t o prov ide a spec if ic hist ologic diagnosis, but t hey c an be usef ul f or det ermining w het her mediast inosc opy or t horac ot omy w ould be bet t er t o y ield a diagnosis. Mediast inal nodes inv olv ed by granulomat ous disease usually undergo spont aneous regression, f requent ly w it h result ant c alc if ic at ion. In some c ases, healing oc c urs w it h ext ensiv e f ibrosis, result ing in airw ay or v asc ular (e.g., superior v ena c av al) obst ruc t ion (F ig. 24- 16). CT is superior t o MRI f or show ing c alc if ic at ions, w hic h are import ant f or est ablishing t he diagnosis of inf lammat ion. MRI, how ev er, c an prov ide c omplement ary inf ormat ion about v asc ular pat enc y , espec ially if t here is a c ont raindic at ion t o t he administ rat ion of iodinat ed c ont rast media. On MRI, c alc if ic at ions and f ibrot ic t issue are of low int ensit y on bot h T 1- and T 2- w eight ed sequenc es (127).

Foregut Cysts F oregut c y st s in t he middle mediast inum are c lassif ied as eit her bronc hogenic or ent eric , depending on t heir hist ology (87). Bronc hogenic c y st s are lined by respirat ory epit helium, and most are loc at ed in t he subc arinal or right parat rac heal area. Ent eric c y st s are lined by gast roint est inal muc osa and are loc at ed in a paraspinal posit ion in t he middle t o post erior mediast inum. In c hildren, most f oregut c y st s are disc ov ered bec ause t hey produc e sy mpt oms of airw ay or esophageal c ompression; oc c asionally t hey are det ec t ed inc ident ally on a c hest radiograph. T he CT appearanc e of a f oregut c y st is usually t hat of a w ell- def ined, round nonenhanc ing mass of near- w at er densit y , ref lec t ing serous c ont ent s (F ig. 2417). Air or an air–f luid lev el c an be present w hen a c ommunic at ion bet w een t he c y st and t he bronc hial t ree or gast roint est inal t rac t dev elops (152). On MRI, f oregut c y st s t y pic ally hav e a low signal int ensit y on T 1- w eight ed images and a v ery high signal int ensit y on T 2- w eight ed images. Some c y st s hav e a

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3579

24 - Pediatric Applications sof t t issue densit y on CT or a high signal int ensit y on T 1- w eight ed images, bec ause t he f luid is prot einac eous or c ont ains c alc ium c arbonat e or oxalat e.

Posterior Mediastinal Masses Post erior mediast inal masses are of neural origin in approximat ely 95% of c ases and may arise f rom sy mpat het ic ganglion c ells (neuroblast oma, ganglioneuroblast oma, or ganglioneuroma) or f rom nerv e sheat hs (neurof ibroma or sc hw annoma). Rarer c auses of post erior mediast inal masses in c hildren inc lude paraspinal absc ess, ly mphoma, neurent eric c y st , lat eral meningoc ele, and ext ramedullary hemat opoiesis. On CT , ganglion c ell t umors appear as paraspinal masses, ext ending ov er t he lengt h of sev eral v ert ebral bodies (237). T hey are f usif orm in shape, of sof t t issue densit y , and c ont ain c alc if ic at ions in up t o 50% of c ases (F ig. 24- 18). Nerv e root t umors t end t o be smaller, spheric al, and oc c ur near t he junc t ion of a v ert ebral body w it h an adjac ent rib. Bot h t y pes of t umors may c ause pressure erosion of a rib. On MRI, most neurogenic t umors hav e low signal int ensit y on T 1- w eight ed images and relat iv ely high signal P.1738 int ensit y on T 2- w eight ed images (F ig. 24- 19). Some t umors hav e low at t enuat ion on CT and int ermediat e t o high signal int ensit y on T 1- w eight ed images bec ause of t heir my elin c ont ent . Bec ause of t heir origin f rom neural t issue, neurogenic t umors hav e a t endenc y t o inv ade t he spinal c anal (F ig. 24- 19). Int raspinal ext ension is ext radural in loc at ion, displac ing and oc c asionally c ompressing t he c ord. Rec ognit ion of int raspinal inv asion is c rit ic al bec ause suc h inv olv ement usually requires radiat ion t herapy or a laminec t omy prior t o t umor debulking.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3580

24 - Pediatric Applications

F igure 24- 16 F ibrosing mediast init is, 14- y ear- old girl. A: Cont rast - enhanc ed c omput ed t omography sc an show s c alc if ied subc arinal ly mph nodes, w it h sec ondary narrow ing of t he lef t mainst em bronc hus (ar r ow s). B: Coronal mult iplanar ref ormat t ed image show s t he f ull ext ent of t he subc arinal nodal mass and c ompression of right and lef t main bronc hi.

F igure 24- 17 Duplic at ion c y st , 15- y ear- old girl. Cont rast - enhanc ed c omput ed t omography show s a homogeneous, near- w at er- densit y c y st (C) in t he middle mediast inum, post erior t o t he t rac hea.

Ot her c auses of post erior mediast inal masses inc lude neurent eric c y st , lat eral meningoc ele, ext ralobar sequest rat ion, and hemangioma. Neurent eric c y st s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3581

24 - Pediatric Applications and lat eral meningoc eles demonst rat e w at er at t enuat ion on CT , low signal int ensit y on T 1- w eight ed images, and v ery high signal int ensit y on T 2-

w eight ed and f at - suppressed images. T he f ormer are assoc iat ed w it h a midline def ec t in one or more v ert ebral bodies. Hemangioma t y pic ally is a unilat eral highly v asc ular paraspinal mass (52). Sequest rat ion somet imes appears as a paraspinal rat her t han int raparenc hy mal mass. Ident if ic at ion of an anomalous f eeding art ery or v ein c an c onf irm t he diagnosis.

Vascular Masses Abnormalit ies of t he aort a and it s branc hes and of t he superior or inf erior v ena c av a (IVC) c an c ause a mass or mediast inal w idening on plain c hest radiography . Eit her CT or MRI c an be used t o det ec t and c harac t erize v asc ular anomalies (16,21,93,94,98,118,140,197,240). Bot h prov ide equiv alent anat omic dat a.

Aortic Arch T he right arc h w it h aberrant lef t subc lav ian art ery and t he double arc h are c ommon c ongenit al anomalies of t he aort a t hat produc e an abnormal mediast inum on plain c hest radiography (16) (F ig. 24- 20). T he double arc h is c harac t erized by t w o arc hes t hat surround t he t rac hea and esophagus. T he arc hes arise f rom a single asc ending aort a and reunit e t o f orm a single desc ending aort a af t er giv ing P.1739 rise t o t he subc lav ian and c arot id art eries. T he right arc h c omponent of a double arc h anomaly usually is more c ephalad and larger t han t he lef t arc h c omponent . Bot h aort ic arc hes usually are pat ent , but oc c asionally t he lef t arc h is at ret ic . In t he right arc h w it h aberrant subc lav ian art ery , t he subc lav ian art ery arises as t he last branc h f rom t he aort ic arc h and t rav erses t he mediast inum behind t he esophagus t o reac h t he lef t arm. T he v asc ular ring is c omplet ed by t he ligament um art eriosum. Airw ay c ompression may be a result of a t ight ligament um art eriosum, a Kommerell's div ert ic ulum, or a midline desc ending aort a (54).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3582

24 - Pediatric Applications

F igure 24- 18 Neuroblast oma, 2- y ear- old girl. A: Cont rast - enhanc ed c omput ed t omography show s a large right paraspinal sof t t issue mass (M). B: Sagit t al mult iplanar ref ormat t ed image show s t he t umor ext ending ov er t he lengt h of sev eral v ert ebral bodies. T he c ranioc audal ext ent of t he mass is bet t er def ined on t he c oronal image.

F igure 24- 19 Neurof ibroma, 15- y ear- old boy . A: Axial T 2- w eight ed magnet ic resonanc e image show s a large, relat iv ely high signal int ensit y , paraspinal mass inv ading t he spinal c anal (ar r ow ), displac ing t he c ord slight ly t o t he right .

Aneury sm of t he t horac ic aort a is anot her c ause of a v asc ular mediast inal mass. T he most c ommon c ause of aneury sms in c hildren is Marf an sy ndrome.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3583

24 - Pediatric Applications Less c ommonly , bac t erial inf ec t ions or Ehlers- Danlos sy ndrome is t he c ause.

Most aneury sms are f usif orm in c onf igurat ion. T hey may be f oc al or ext end t he ent ire lengt h of t he v essel.

Superior Vena Cava Venous anomalies produc ing mediast inal w idening inc lude persist ent lef t superior v ena c av a and int errupt ion of t he IVC (13,49). Persist ent lef t superior v ena c av a, result ing f rom f ailure of regression of t he lef t c ommon and ant erior c ardinal v eins, drains t he lef t jugular and subc lav ian v eins, and in some c ases, t he lef t superior int erc ost al v ein. T he persist ent v ena c av a lies lat eral t o t he lef t c ommon c arot id art ery and ant erior t o t he lef t subc lav ian art ery , desc ends lat eral t o t he main pulmonary art ery , and drains int o t he c oronary sinus post erior t o t he lef t v ent ric le. Dilat at ion of t he azy gos or hemiazy gos v ein is a c ause of a post erior mediast inal or right parat rac heal mass. When t he inf rahepat ic segment of t he IVC abov e t he renal v eins f ails t o dev elop, blood f rom below t he renal v eins ret urns t o t he heart v ia t he azy gos or hemiazy gos v eins, w it h result ant dilat at ion of t hese st ruc t ures. T y pic ally , t he hemiazy gos v ein c rosses behind t he aort a t o join t he dilat ed azy gos v ein, w hic h in t urn drains int o t he azy gos arc h (F ig. 24- 21). T he suprarenal port ion of t he IVC also is absent , and t he hepat ic v eins drain direc t ly int o t he right at rium.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3584

24 - Pediatric Applications

F igure 24- 20 Aort ic arc h anomalies. A: Right arc h w it h an aberrant lef t subc lav ian art ery , 3- y ear- old girl. Cont rast - enhanc ed c omput ed t omography (CT ) sc an demonst rat es a right aort ic arc h (R) giv ing rise t o t he lef t subc lav ian art ery (SA), w hic h passes behind t he t rac hea and esophagus t o reac h t he lef t arm. B: T hree- dimensional rec onst ruc t ion show s t he lef t subc lav ian art ery (ar r ow ) arising as t he last branc h of f t he right - sided aort a. RS, right subc lav ian art ery ; RC, right c arot id art ery ; LC, lef t c arot id art ery . C : Double arc h in an 17- y ear- old girl. CT show s t he t w o limbs of t he double arc h enc irc ling t he t rac hea and esophagus. R, right arc h; L, lef t arc h. (C reprint ed f rom Siegel MJ. Mult iplanar and t hree- dimensional row CT of t horac ic v essels and airw ay s in t he pediat ric populat ion. Radiology 2003;229:641–650, w it h permission.)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3585

24 - Pediatric Applications

F igure 24- 21 Azy gos c ont inuat ion of inf erior v ena c av a. A: Comput ed t omography sc an at t he lev el of t he dist al aort a (A) show s a markedly dilat ed azy gos v ein (ar r ow ). B: A dilat ed azy gos v ein (ar r ow ) is not ed at t he lev el of t he liv er. T he inf erior v ena c av a is absent .

P.1740 P.1741

Comparative Imaging and Clinical Applications CT and MRI are bot h sensit iv e f or det ec t ion of mediast inal masses and prov ide c omparable inf ormat ion on t he presenc e and size of a lesion. CT usually suf f ic es f or assessing ant erior and middle mediast inal masses, w it h t he exc ept ion of c y st ic hy groma. In pat ient s w it h c y st ic hy groma, MRI is superior t o CT in def ining t he ext ent of t he t umor, part ic ularly sof t t issue inf ilt rat ion. MRI is t he met hod of c hoic e f or ev aluat ing pat ient s w it h post erior mediast inal masses suspec t ed of being of neurogenic origin, bec ause of t he high likelihood of int raspinal ext ension.

Lungs Congenital Anomalies Congenit al lung anomalies inc lude a v ariet y of c ondit ions inv olv ing t he pulmonary parenc hy ma, t he pulmonary v asc ulat ure, or a c ombinat ion of bot h. Bec ause many of t hese c ondit ions are assoc iat ed w it h eit her a parenc hy mal lesion or anomalous v essels, t hey are w ell suit ed f or analy sis by CT sc anning.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3586

24 - Pediatric Applications In selec t ed c ases, MRI c an prov ide c omplement ary inf ormat ion about t he presenc e or absenc e of an anomalous v essel.

Anomalies With Normal Vasculature Congenit al lobar emphy sema, c y st ic adenomat oid malf ormat ion, and bronc hial at resia are anomalies result ing f rom abnormal bronc hial dev elopment . Chest radiography of t en suf f ic es f or diagnosis. CT is perf ormed t o c onf irm t he diagnosis and t o det ermine it s ext ent in pat ient s in w hom surgery is c ont emplat ed. Congenit al lobar emphy sema is c harac t erized by hy perinf lat ion of a lobe (42). T he exac t et iology is unknow n, but many c ases are believ ed t o be c aused by bronc hial obst ruc t ion. T he af f ec t ed pat ient usually present s in t he f irst six mont hs of lif e w it h respirat ory dist ress. CT show s a hy perinf lat ed lobe w it h at t enuat ed v asc ularit y , c ompression of ipsilat eral adjac ent lobes, and mediast inal shif t t o t he opposit e side (F ig. 24- 22). T he lef t upper lobe is inv olv ed in about 45% of c ases, t he right middle lobe in 30%, t he right upper lobe in 20%, and t w o lobes in 5% of c ases (42). Cy st ic adenomat oid malf ormat ion is c harac t erized by an ov ergrow t h of dist al bronc hial t issue, w it h f ormat ion of a c y st ic mass. Sy mpt oms of respirat ory dist ress usually oc c ur soon af t er birt h. Hist ologic ally , t here are t hree t y pes of c y st ic adenomat oid malf ormat ion: t y pe I (50% of c ases) c ont ains a single c y st or mult iple large c y st s (great er t han 10 mm in diamet er); t y pe II (41%) c ont ains mult iple small c y st s (1 t o 10 mm in diamet er); and t y pe III (9%) is a solid lesion t o v isual inspec t ion, but c ont ains mic rosc opic c y st s (42,125). T he anomaly oc c urs w it h equal f requenc y in bot h lungs, alt hough t here is slight upper lobe predominanc e. On CT , c y st ic adenomat oid malf ormat ion appears as a parenc hy mal mass t hat may be predominant ly c y st ic or solid or c ont ain an admixt ure of c y st ic and solid c omponent s (42,125,205) (F ig. 24- 23). Air–f luid lev els oc c asionally c an be seen w it hin t he c y st s.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3587

24 - Pediatric Applications

F igure 24- 22 Congenit al lobar emphy sema, 6- mont h- old boy . Comput ed t omography t hrough t he upper t horax show s a hy perinf lat ed lef t upper lobe w it h at t enuat ed v asc ularit y .

Bronc hial at resia result s f rom abnormal dev elopment of a segment al or subsegment al bronc hus. It rarely c auses sy mpt oms and is usually disc ov ered on c hest radiographs perf ormed f or ot her indic at ions. T he CT f eat ures of bronc hial at resia inc lude ov er- aerat ed lung dist al t o t he at resia and a round, ov oid, or branc hing densit y near t he hilum, represent ing muc oid impac t ion just bey ond t he at ret ic bronc hus (3) (F ig. 24- 24).

Anomalies With Abnormal Vasculature Sequest rat ion, hy pogenet ic lung sy ndrome, and art eriov enous malf ormat ion (AVM) are c ongenit al anomalies w it h abnormal v asc ulat ure. Chronic or rec urrent segment al or subsegment al pneumonit is in c hildren, espec ially at a lung base, is a f inding suggest iv e of sequest rat ion. Pat hologic ally , a sequest ered port ion of lung has no normal c onnec t ion w it h t he t rac heobronc hial t ree and is supplied by an anomalous art ery , usually arising f rom t he aort a. When t he sequest ered lung is c onf ined w it hin t he normal v isc eral pleura and has v enous drainage t o t he pulmonary v eins, it is t ermed “ int ralobar.” T he sequest ered lung is t ermed “ ext ralobar” w hen it has it s ow n pleura and v enous drainage t o sy st emic v eins. Alt hough plain c hest radiography or c onv ent ional t omography oc c asionally may demonst rat e an anomalous v essel, CT and MRI are more sensit iv e f or ident if y ing suc h a v essel (66,67,128). CT sc anning af t er an injec t ion of c ont rast mat erial demonst rat es opac if ic at ion of t he anomalous v essel

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3588

24 - Pediatric Applications immediat ely f ollow ing enhanc ement of t he desc ending t horac ic aort a. T he anomalous v essel of t en c an be t rac ed t o t he sequest ered lung. T he CT appearanc e of P.1742

t he pulmonary parenc hy ma depends on w het her or not t he sequest ered lung is aerat ed. When t he sequest rat ion c ommunic at es w it h t he remainder of t he lung, usually af t er being inf ec t ed, it appears c y st ic ; a sequest rat ion t hat does not c ommunic at e appears as a homogeneous densit y , usually in t he post erior port ion of t he low er lobe (F igs. 24- 25 and 24- 26). On MRI, t he f eeding v essel appears as an area of signal v oid on T 1- w eight ed spin- ec ho images and as a hy perint ense area on GRE sequenc es. T he parenc hy mal port ion of t he sequest rat ion appears as an area of int ermediat e or high signal int ensit y .

F igure 24- 23 Cy st ic adenomat oid malf ormat ion. A: T y pe I lesion, 15- y ear- old girl, mult iloc ular mass in t he right upper lobe c ont aining numerous large c y st s. B: T y pe II malf ormat ion, inf ant girl, a c omplex mass in t he lef t low er lobe c ont aining mult iple small c y st s.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3589

24 - Pediatric Applications

F igure 24- 24 Bronc hial at resia, inf ant girl. Comput ed t omography show s an ov oid sof t t issue nodule (ar r ow ) in t he lef t low er lobe. T he nodule is surrounded by ov er- aerat ed lung result ing f rom c ollat eral air drif t .

An addit ional c ongenit al lung abnormalit y w it h v asc ular anomalies t hat c an be diagnosed by CT or MRI is t he hy pogenet ic lung or sc imit ar sy ndrome (82,130,285). CT and MRI f indings inc lude a small right lung, ipsilat eral mediast inal displac ement , a c orresponding small pulmonary art ery , and oc c asionally part ial anomalous pulmonary v enous ret urn f rom t he right lung t o t he IVC (F ig. 24- 27). Ot her assoc iat ed anomalies inc lude sy st emic art erial supply t o t he hy pogenet ic lung, ac c essory diaphragm, and horseshoe lung. Horseshoe lung is a rare anomaly in w hic h t he post erobasal segment s of bot h lungs are f used behind t he peric ardial sac . Pulmonary AVM is c harac t erized by a direc t c ommunic at ion bet w een a pulmonary art ery and v ein w it hout an int erv ening c apillary bed. When t he diagnosis is suspec t ed on c hest radiographs, CT and MRI are usef ul t o est ablish t he def init iv e diagnosis (82,96,138,196,207). How ev er, if surgery or embolizat ion is planned, art eriography may be needed t o demonst rat e t he prec ise v asc ular anat omy of c omplex f ist ulae or t he presenc e of mult iple t iny AVMs t hat may not be v isible on CT or MRI. On CT and MRI, AVMs appear as rounded or lobular masses w it h rapid enhanc ement and w ashout af t er int rav enous c ont rast medium administ rat ion. Enhanc ement t y pic ally oc c urs af t er enhanc ement of t he right v ent ric le and bef ore enhanc ement of t he lef t at rium and lef t v ent ric le.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3590

24 - Pediatric Applications Pulmonary Metastases CT is a v aluable t ec hnique f or det ec t ion of pulmonary met ast ases in pat ient s

w it h know n malignanc ies w it h a high propensit y f or lung disseminat ion, suc h as Wilms t umor, ost eogenic sarc oma, and rhabdomy osarc oma. Demonst rat ion of one or more pulmonary nodules in suc h pat ient s, or doc ument at ion of addit ional nodules in a pat ient w it h an apparent solit ary met ast asis f or w hom surgery is planned, may be c rit ic al t o t reat ment planning. P.1743 In t he f irst inst anc e, suc h det ec t ion may lead t o addit ional t reat ment (surgery , c hemot herapy , or radiat ion), w hereas in t he lat t er set t ing, demonst rat ion of sev eral met ast at ic nodules may negat e surgic al plans. Conf usion w it h benign granulomas does not appear t o be as signif ic ant a c linic al problem in c hildren as it is in adult s; in c hildren, almost all nonc alc if ied nodules depic t ed by CT are a result of met ast ases (F ig. 24- 28) rat her t han granulomat ous disease or a primary neoplasm.

F igure 24- 25 Int ralobar sequest rat ion, 6- mont h- old girl w it h rec urrent lef t low er lobe pneumonia. A: Comput ed t omography demonst rat es t he anomalous art erial supply (ar r ow ) t o t he sequest ered lung (S) arising f rom t he t horac ic aort a (A). B: Post erior t hree- dimensional v olume- rendered image show s t he anomalous art erial supply (ar r ow ) f rom t he desc ending aort a t o t he sequest ered lung (S) and t he anomalous v enous drainage (V) t o t he lef t at rium. (Reprint ed f rom Siegel MJ. Mult iplanar and t hree- dimensional row CT of t horac ic v essels and airw ay s in t he pediat ric populat ion. Radiology 2003;229:641–650, w it h permission.)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3591

24 - Pediatric Applications MRI c an det ec t large parenc hy mal nodules, but it is not as sensit iv e as CT in det ec t ing nodules less t han 1 c m in diamet er bec ause of it s poorer spat ial

resolut ion. Henc e, CT remains t he imaging met hod of c hoic e f or det ec t ing and c harac t erizing pulmonary nodules.

F igure 24- 26 Ext ralobar pulmonary sequest rat ion, 6- mont h- old boy w it h a lef t paraspinal mass on c hest radiographs. A: Comput ed t omography (CT ) sc an show s t he anomalous v ein (ar r ow ) arising f rom t he sequest ered lung (S) and c rossing t he midline t o t he right hemit horax. B: More c audal CT image demonst rat es t he anomalous art erial v essel (w hit e ar r ow ) arising f rom t he c eliac art ery (blac k ar r ow ). A, aort a. (Reprint ed f rom Lee E, Siegel MJ, F oglia R. Ev aluat ion of angioarc hit ec t ure of pulmonary sequest rat ion in pediat ric pat ient s using 3D MDCT angiography . AJR Am J Roent genol 2004;183:183–188, w it h permission.)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3592

24 - Pediatric Applications

F igure 24- 27 Sc imit ar sy ndrome w it h part ial anomalous v enous ret urn, 10y ear- old girl. A: Axial c omput ed t omography sc an at t he lev el of t he v ent ric les show s part of t he anomalous pulmonary v ein (ar r ow ). B: Sev eral c ent imet ers low er, t he anomalous v essel ent ers t he int rahepat ic inf erior v ena c av a (C). Not e t hat t he right hemit horax is smaller t han t he lef t and t hat t here is mediast inal shif t t o t he right . C : Volume- rendered t hree- dimensional display depic t s t he ent ire c ourse of t he anomalous v essel on one image. C, inf erior v ena c av a; arrow , anomalous v ein.

P.1744

Diffuse Parenchymal Disease Chest radiography remains t he imaging st udy of c hoic e f or ev aluat ing dif f use parenc hy mal lung disease. CT , how ev er, c an be usef ul t o bet t er def ine and c harac t erize an abnormalit y suspec t ed on c onv ent ional c hest radiography ,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3593

24 - Pediatric Applications espec ially w hen t he CT examinat ion is perf ormed w it h high- resolut ion t ec hnique using narrow (1- t o 2- mm) c ollimat ion and a high spat ial f requenc y rec onst ruc t ion algorit hm. Indic at ions f or high- resolut ion CT of t he lung

parenc hy ma in c hildren inc lude: (a) det ec t ion of disease in c hildren w ho are at inc reased risk f or lung disease (e.g., immunoc ompromised pat ient s) and w ho hav e respirat ory sy mpt oms but a normal c hest radiograph; (b) det erminat ion of t he ext ent , dist ribut ion, and c harac t er of lung diseases; (c ) loc alizat ion of abnormal lung f or biopsy ; and (d) assessment of t he response t o t reat ment (135,151,159,160,172,234). Alt hough many lung diseases in c hildren hav e nonspec if ic f indings, some hav e c harac t erist ic appearanc es. Cy st ic f ibrosis is c harac t erized by dif f use hy perinf lat ion, bronc hiec t asis, and peribronc hial sof t t issue t hic kening (F ig. 24- 29), w hereas bronc hopulmonary dy splasia is c harac t erized by hy perinf lat ion, c y st ic airspac es, and sept al lines, w it hout bronc hiec t asis (135,151,172,186,234) (F ig. 24- 30). Bronc hiolit is oblit erans is manif est ed as pat c hy areas of ov erinf lat ion w it h result ant at t enuat ion of pulmonary v essels, somet imes in c onjunc t ion w it h bronc hiec t asis (35,136). In older c hildren w ho are able t o suspend respirat ion, dy namic CT w it h inspirat ory and expirat ory imaging may aid in c onf irming t he diagnosis of f oc al air- t rapping (F ig. 24- 31) (215). T he c ommon int erst it ial lung diseases in c hildren inc lude Langerhans c ell hist ioc y t osis and pulmonary f ibrosis. P.1745 CT f indings of Langerhans c ell hist ioc y t osis inc lude small pulmonary nodules (less t han 5 mm) in t he early st ages of t he disease and t hin- w alled c y st s and sept al t hic kening in lat er st ages of t he disease (162) (F ig. 24- 32). Pulmonary f ibrosis is c harac t erized by sept al t hic kening, t rac t ion bronc hiec t asis, and subpleural honey c ombing w it h arc hit ec t ural dist ort ion. T he most c ommon airspac e disease is pulmonary alv eolar prot einosis, w hic h is c harac t erized by ground- glass opac it y and alv eolar c onsolidat ion (2) (F ig. 24- 33).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3594

24 - Pediatric Applications

F igure 24- 28 Met ast at ic Wilms t umor. A large, sof t t issue nodule is seen in t he right low er lobe.

Pulmonary Infections Conv ent ional c hest radiography remains t he imaging t ec hnique of c hoic e t o exc lude or c onf irm a c linic ally suspec t ed pulmonary inf ec t ion, t o ev aluat e f or t he presenc e of parapneumonic ef f usion, and t o assess t he response t o t reat ment . In pat ient s w ho do not respond t o appropriat e t herapy , CT is usef ul t o assess suspec t ed c omplic at ions, inc luding pneumat oc ele f ormat ion, absc ess, lung nec rosis (i.e., nec rot izing pneumonia), and empy ema (56,57).

F igure 24- 29 Cy st ic f ibrosis. A, B: High- resolut ion c omput ed t omography sec t ions at t w o lev els demonst rat e dif f use c y st ic bronc hiec t asis and peribronc hial t hic kening.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3595

24 - Pediatric Applications

On CT , pneumat oc eles appear as single or mult iple, t hin- w alled, c y st ic lesions, w hereas absc esses hav e t hic k, irregular w alls and may c ont ain an air–f luid lev el if t hey dev elop a c ommunic at ion w it h t he bronc hus (F ig. 24- 34). Nec rot izing pneumonia manif est s as c av it ary lesions w it hin an area of c onsolidat ion in c onjunc t ion w it h dec reased parenc hy mal enhanc ement af t er administ rat ion of int rav enous c ont rast medium (F ig. 24- 35). Nec rot izing pneumonia is import ant t o rec ognize, bec ause most c hildren w it h t his f inding need t o be hospit alized and require a longer c ourse of ant ibiot ic t herapy t han do c hildren w it h unc omplic at ed pneumonia. Empy ema is c harac t erized by P.1746 pleural f luid and t hic kening of t he adjac ent v isc eral and pariet al pleura. F requent ly , t here is edema/inf lammat ion of t he ext rapleural t issues as w ell.

F igure 24- 30 Bronc hopulmonary dy splasia. High- resolut ion c omput ed t omography show s dif f use sept al lines w it hout bronc hiec t asis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3596

24 - Pediatric Applications F igure 24- 31 Bronc hiolit is oblit erans af t er bilat eral lung t ransplant at ion, 14y ear- old girl. A: Axial c omput ed t omography sec t ion at inspirat ion show s mild mosaic at t enuat ion. B: Image during expirat ion show s more prominent mosaic at t enuat ion. T he low er at t enuat ion areas indic at e air t rapping in small airw ay s.

Parenchymal or Pleural Disease In some pat ient s, CT c an be helpf ul in dist inguishing bet w een a parenc hy mal proc ess and a pleural or ext rapleural proc ess. T he f eat ures of parenc hy mal lesions are a rounded or ov al shape, ac ut e or abrupt angles at t he int erf ac e w it h t he c hest w all, and poorly def ined margins w it h t he adjac ent lung. T he CT f eat ures of pleural disease are a lent ic ular or c resc ent ic shape, obt use or t apering angles at t he int erf ac e w it h t he c hest w all, and w ell- def ined margins w it h adjac ent lung, bone, and sof t t issues. Ext rapleural lesions are lent ic ular in shape w it h poorly def ined margins and obt use or t apering angles at t he int erf ac e w it h t he pleura. T w o- dimensional (2D) and 3D rec onst ruc t ions in c oronal and sagit t al planes may be helpf ul in c harac t erizing a lesion as int raparenc hy mal or pleural based.

F igure 24- 32 Langerhans c ell hist ioc y t osis. High- resolut ion c omput ed t omography show s mult iple small air- f illed, t hin- w alled c y st s.

MRI c urrent ly has a limit ed role in ev aluat ing pulmonary disease, inc luding pleural proc esses. Alt hough it is sensit iv e f or det ec t ion of a v ariet y of pleural and parenc hy mal disorders, it adds lit t le c linic ally import ant inf ormat ion ov er t hat gained w it h CT .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3597

24 - Pediatric Applications

F igure 24- 33 Pulmonary alv eolar prot einosis, 15- y ear- old girl w it h short ness of breat h. High- resolut ion c omput ed t omography t hrough t he lung bases show s ext ensiv e ground- glass opac it y and int erst it ial t hic kening, c reat ing a “ c razy pav ing” appearanc e. (F rom Siegel MJ, Coley B. Pediat ric c ore c urric ulum. Philadelphia: Lippinc ot t Williams & Wilkins, 2005, w it h permission.

F igure 24- 34 Lung absc ess, 15- y ear- old boy . Cont rast - enhanc ed c omput ed t omography show s a t hic k- w alled c av it ary lesion adjac ent t o t he pleural surf ac e.

P.1747

Airway Disease T he t rac heobronc hial t ree, inc luding t he t rac hea, c arina, and mainst em and lobar bronc hi, are easily seen by CT . CT images of t he airw ay s are ac quired in t he axial plane and post proc essed w it h bot h mult iplanar ref ormat ions in t he c oronal, oblique, and sagit t al planes and 3D v olume- rendering t ec hniques

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3598

24 - Pediatric Applications

(261). Axial images are mandat ory f or assessing ext raluminal disease, inc luding t he lung parenc hy ma and mediast inal st ruc t ures. Mult iplanar and v olume renderings are helpf ul in delineat ing mild st enoses and c omplex c ongenit al airw ay abnormalit ies, suc h as abnormal origins of t he bronc hi or bronc hoesophageal f ist ulas. T hey also c an assist in show ing t he relat ionship of t he airw ay t o surrounding v essels. T he more f requent indic at ions prompt ing CT of t he airw ay are: (a) ev aluat ion of c ongenit al t rac heobronc hial anomalies (73,286), (b) assessment of t rac heal narrow ing (99,160,187), and (c ) det ec t ion or c onf irmat ion of t rac heomalac ia (76). T rac heobronc hial neoplasia is a rare indic at ion f or CT in c hildren. T he c ommon c ongenit al anomalies are t he t rac heal and c ardiac bronc hi. T he t rac heal or pig bronc hus arises almost alw ay s on t he right side of t he t rac hea and usually w it hin 2 c m of t he c arina (73,286) (F ig. 24- 36). T he ac c essory c ardiac bronc hus nearly alw ay s arises f rom t he inf erior medial w all of t he right main or int ermediat e bronc hus. Bot h t y pes of bronc hi may serv e as reserv oirs f or inf ec t ious organisms leading t o rec urrent pneumonia. T rac heal st ric t ures are usually t he sequelae of int ubat ion, t rac heost omy plac ement , or surgic al anast omoses. T rac heomalac ia ref ers t o an abnormal w eakness of t he t rac heal w alls and support ing t issues, result ing in luminal c ollapse during expirat ion. When t rac heomalac ia is suspec t ed, sc ans are ac quired at bot h end- inspirat ion and end- expirat ion and t hen ref ormat t ed in t he c oronal and sagit t al planes. T his t ec hnique is limit ed t o c ooperat iv e pat ient s or t o pat ient s w ho are on assist ed v ent ilat ion. T he diagnosis of t rac heomalac ia c an be made by CT w hen t here is 50% or great er reduc t ion in t ransluminal diamet er during expirat ion. A less f requent indic at ion f or airw ay CT is f oreign body aspirat ion (132). T he f oreign body c an be prec isely loc alized by spiral CT prior t o bronc hosc opic ret riev al. Dy namic CT w it h inspirat ory and expirat ory imaging c an show t he air t rapping dist al t o t he bronc hial obst ruc t ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3599

24 - Pediatric Applications

F igure 24- 35 Nec rot izing pneumonia. A, B: T w o c ont rast - enhanc ed c omput ed t omography images show lef t lung c onsolidat ion w it hout c ont rast enhanc ement and c av it ary c hanges indic at ing lung nec rosis.

F igure 24- 36 T rac heal bronc hus. Coronal rec onst ruc t ion c omput ed t omography sc an show s an ec t opic right upper lobe bronc hus (ar r ow ) arising f rom t he proximal t rac hea.

P.1748

Pulmonary Arteries and Veins Congenit al anomalies of t he pulmonary art eries and v eins are also w ell suit ed t o CT and MR angiography . T he c ommon anomalies of t he pulmonary art eries

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3600

24 - Pediatric Applications are agenesis or hy poplasia and anomalous origin of t he lef t pulmonary art ery f rom t he right pulmonary art ery (pulmonary sling) (F ig. 24- 37) (189). T he c ommon anomaly of t he pulmonary v eins is anomalous ret urn, w hic h oc c urs w hen a pulmonary v ein ent ers t he right heart or a sy st emic v ein. T he anomalous c onnec t ion c ommonly inv olv es t he lef t superior, right inf erior, and

right superior pulmonary v eins (50,277). T he anomalous lef t superior pulmonary v ein drains int o t he lef t brac hioc ephalic v ein, produc ing a v ert ic al v ein t hat c ourses lat eral t o t he aort ic arc h and aort opulmonary w indow . T he anomalous right inf erior pulmonary v ein drains c ephalad int o t he azy gous v ein or c audal int o t he subdiaphragmat ic IVC or port al v ein. T he right superior pulmonary v ein drains int o t he superior v ena c av a and is of t en assoc iat ed w it h a sec undum at rial sept al def ec t . Anomalous ret urn t o t he right lung c an oc c ur in assoc iat ion w it h t he hy pogenet ic lung sy ndrome (see F ig. 24- 27).

F igure 24- 37 Pulmonary sling, 3- mont h- old girl. Cont rast - enhanc ed axial c omput ed t omography image show s anomalous lef t pulmonary art ery (ar r ow ) arising f rom right pulmonary art ery (R) and c ompressing t rac hea. (Court esy of Joseph Sc hoepf , MD.)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3601

24 - Pediatric Applications

F igure 24- 38 Aort ic c oarc t at ion. Sagit t al c omput ed t omography rec onst ruc t ion show s mild hy poplasia of t he t ransv erse aort ic arc h and an area of high- grade c oarc t at ion (ar r ow ) just dist al t o t he origin of t he subc lav ian art ery .

Cardiac Disease T he presenc e of most c ongenit al and ac quired c ardiac lesions c an be det ermined w it h ec hoc ardiography in c ombinat ion w it h Doppler sonography , but CT and MRI c an be of use w hen ec hoc ardiography prov ides inadequat e inf ormat ion (26,37,75,77,83,95,141). T he major indic at ions f or CT and MRI in c ongenit al c ardiac anomalies inc lude: (a) ev aluat ion of t he size and pat enc y of t he pulmonary art eries in pat ient s w it h c y anot ic heart disease, suc h as pulmonary at resia and t et rology of F allot (283), (b) assessment of t he ext ent and sev erit y of aort ic c oarc t at ion (41,129,141) (F ig. 24- 38) and t he degree of suprav alv ar aort ic st enosis, (c ) det ec t ion of anomalous origin of t he c oronary art ery , (d) det erminat ion P.1749

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3602

24 - Pediatric Applications

of t he ext rac ardiac anat omy in pat ient s w it h c omplex c ongenit al heart disease (e.g., great v essel relat ionships, bronc hial c ollat eral v essels, abdominal sit us) (38,55,124), (e) ev aluat ion of post operat iv e anat omy and surgic ally c reat ed sy st emic - t o- pulmonary art ery shunt s and int rac ardiac baf f les (201) (F igs. 2439 and 24- 40), and (f ) det ec t ion of arrhy t hmogenic right v ent ric ular c ardiomy opat hy (11). CT and MRI also c an prov ide inf ormat ion about ac quired lesions, inc luding int rac ardiac or peric ardial masses (225).

F igure 24- 39 Jat ene proc edure. Cont rast - enhanc ed c omput ed t omography af t er an art erial sw it c h proc edure show s c harac t erist ic draping of t he pulmonary art eries (PA) around t he aort a (A).

ABDOMEN T he appearanc e of t he abdomen on CT and MR examinat ions is similar in adult s and c hildren, exc ept f or t he limit at ions imposed by t he small size of t he st ruc t ures being examined and t he relat iv e pauc it y of periv isc eral f at . T he major c linic al quest ions usually prompt ing CT examinat ion of t he abdomen are: (a) det erminat ion of t he sit e of origin, ext ent , and c harac t er of an abdominal mass; (b) det erminat ion of t he ext ent of a prov en ly mphoma; (c ) ev aluat ion of t he ext ent of injury f rom blunt abdominal t rauma; and (d) det erminat ion of t he presenc e or absenc e of a suspec t ed absc ess. Less of t en, CT is used t o ev aluat e non- neoplast ic , parenc hy mal disease of t he kidney , liv er, panc reas, and gast roint est inal t rac t or t o assess abnormalit ies of t he major abdominal v essels.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3603

24 - Pediatric Applications

F igure 24- 40 T et ralogy of F allot . Pat ient had undergone palliat iv e Blaloc k T aussig shunt in inf anc y . Axial image show s v ent ric ular sept al def ec t (ar r ow ) and right v ent ric ular hy pert rophy (RV).

Abdominal masses in t he pediat ric populat ion are predominant ly ret roperit oneal in loc at ion, w it h t he kidney being t he sourc e in more t han half of t he c ases. In neonat es, most abdominal masses are benign; bey ond t he neonat al period, t he perc ent age of malignant neoplasms inc reases. CT and MRI hav e an import ant role in older inf ant s and c hildren in det ermining t he sit e of origin, c harac t erist ic s, and ext ent of a mass, as w ell as t he presenc e or absenc e of met ast at ic disease (165,227,238,239,249).

Renal Masses Solid Renal Tumors Wilms Tumor Wilms t umor is t he most c ommon primary malignant renal t umor of c hildhood (71,78,148). Af f ec t ed pat ient s generally are under 4 y ears of age. T hey present most f requent ly w it h a palpable abdominal mass, and less of t en w it h abdominal pain, f ev er, and mic rosc opic or gross hemat uria. Approximat ely 10% of c hildren hav e met ast at ic disease at present at ion (78). Met ast ases are c harac t erist ic ally t o t he lungs and less f requent ly t o t he liv er. Wilms t umor appears as a large, spheric al, at least part ially int rarenal mass w it h a sof t t issue densit y on CT and an MR signal int ensit y equal t o or low er t han t hat of normal renal c ort ex on T 1- w eight ed images and equal t o or higher

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3604

24 - Pediatric Applications t han t hat of normal parenc hy ma on T 2- w eight ed images

(71,148,163,238,239,249) (F igs. 24- 41 and 24- 42). T he t umor enhanc es af t er int rav enous administ rat ion of c ont rast medium, but usually t o a lesser ext ent t han t he adjac ent parenc hy ma. Approximat ely 80% of t umors are het erogeneous, bec ause t hey c ont ain areas of nec rosis or hemorrhage. Less t han 15% of Wilms t umors c ont ain c alc if ic at ions or f at as a minor c omponent . Poor or absent f unc t ion of t he inv olv ed kidney oc c urs in about 10% of pat ient s, result ing f rom inv asion or c ompression of hilar v essels or t he renal pelv is, or f rom ext ensiv e inf ilt rat ion of t umor t hroughout t he kidney (180). Bilat eral sy nc hronous t umors oc c ur in 5% t o 10% of pat ient s (F ig. 24- 43). Loc al spread of t umor may t ake t he f orm of ext ension t hrough t he c apsule int o t he perinephric spac e (20% of c ases), ret roperit oneal ly mphadenopat hy (20%), or renal v ein or IVC t hrombosis (5% t o 10%) (78). Perinephric ext ension may be seen as a t hic kened renal c apsule or as nodular or st reaky densit ies in t he perinephric f at . T he P.1750 diagnosis of ly mph node inv olv ement is based on demonst rat ion of perirenal, periaort ic , parac av al, or ret roperit oneal ly mph nodes. Any ident if ied ret roperit oneal ly mph node, regardless of size, should be regarded w it h suspic ion. Alt hough normal- size nodes are c ommonly demonst rat ed on abdominal CT and MRI in adult s, suc h nodes are rarely , if ev er, seen in inf ant s and y oung c hildren.

F igure 24- 41 Wilms t umor in a 2- y ear- old boy . A, B: Cont rast - enhanc ed axial c omput ed t omography and c oronal mult iplanar rec onst ruc t ion demonst rat e a large, round, low - densit y mass t hat dist ort s and displac es t he enhanc ing parenc hy ma (ar r ow s) in t he low er pole of t he right kidney .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3605

24 - Pediatric Applications Neit her CT nor MRI c an det ec t t umor t hrombus in t he small int rarenal v eins,

but bot h imaging t ec hniques are c apable of ident if y ing t umor in t he main renal v ein or IVC. T he presenc e or absenc e of IVC inv asion is an import ant det erminant of t he surgic al approac h. A t horac oabdominal approac h is required f or remov al of t umor t hrombus ext ending t o or abov e t he c onf luenc e of t he hepat ic v eins, w hereas an abdominal approac h alone is sat isf ac t ory f or int rav asc ular t hrombus below t he hepat ic v eins. On CT , t he t hrombus is seen as a low - densit y int raluminal mass. On MRI, t umor t hrombus is hy perint ense t o f low ing blood on spin- ec ho sequenc es and is hy point ense t o f low ing blood on GRE images.

F igure 24- 42 Wilms t umor in a 2- y ear- old girl. T 2- w eight ed t ransaxial magnet ic resonanc e image show s a large mass replac ing most of t he lef t kidney . T he predominant signal int ensit y is similar t o t hat of normal parenc hy ma. Sev eral areas of low signal int ensit y , represent ing nec rosis, are not ed in t he t umor.

Af t er t herapy , CT or MRI c an be used t o det ec t loc al rec urrenc e and hepat ic met ast ases. Pat ient s w it h inc omplet e resec t ion of t umor, ly mph node inv olv ement , and v asc ular inv asion hav e t he highest risk f or post operat iv e rec urrenc e. F eat ures t hat suggest loc alized rec urrenc e are a sof t t issue P.1751 mass in t he empt y renal f ossa and ipsilat eral psoas musc le enlargement .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3606

24 - Pediatric Applications

F igure 24- 43 Bilat eral Wilms t umors. Comput ed t omography sc an show s t w o nonenhanc ing low - at t enuat ion Wilms t umors in t he lef t kidney and one in t he right kidney .

F igure 24- 44 Nephroblast omat osis, 12- mont h- old girl. Comput ed t omography demonst rat es an enlarged right kidney w it h a rind of sof t t issue in t he subc apsular spac e c ompressing t he enhanc ing renal c ort ex.

Nephroblastomatosis Nephroblast omat osis is an abnormalit y of nephrogenesis c harac t erized by persist enc e of f et al renal blast ema bey ond 36 w eeks of int raut erine gest at ion. Nephroblast omat osis it self is not a malignant c ondit ion, but it is a prec ursor t o Wilms t umor. Renal inv olv ement by nephroblast omat osis is of t en bilat eral. T he CT f indings of nephroblast omat osis inc lude (a) nephromegaly , (b) low at t enuat ion subc apsular masses or nodules, and (c ) poor c ort ic omedullary

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3607

24 - Pediatric Applications dif f erent iat ion (84,145,174,202) (F ig. 24- 44). On gadolinium- enhanc ed T 1w eight ed MR images, nephroblast omat osis is hy point ense relat iv e t o normal renal t issue (84). On T 2- w eight ed images, nephrogenic rest s usually are isoint ense or slight ly hy perint ense t o renal c ort ex, but oc c asionally t hey c an be hy point ense.

Mesoblastic Nephroma Mesoblast ic nephroma, also t ermed f et al renal hamart oma, is a benign neoplasm usually present ing in t he f irst y ear of lif e as an abdominal mass. T he CT and MRI f indings are t hose of a f airly unif orm int rarenal mass t hat enhanc es af t er int rav enous c ont rast medium injec t ion, alt hough not t o t he ext ent of normal renal parenc hy ma (30,199,249). Oc c asionally , areas of c y st ic degenerat ion and nec rosis are seen as low - densit y f oc i w it hin t he t umor. Inv asion of t he v asc ular pedic le or ext ension int o t he renal pelv is is rare, alt hough t he t umor c an penet rat e t he renal c apsule and inv ade t he perinephric spac e. Dif f erent iat ion bet w een Wilms t umor and mesoblast ic nephroma usually is not possible w it hout a biopsy .

Lymphoma Renal inv olv ement by ly mphoma oc c urs inf requent ly during t he c ourse of disease, but it is not unc ommon at aut opsy . T his c omplic at ion is more of t en assoc iat ed w it h t he non- Hodgkin t han w it h t he Hodgkin f orm of disease, and it is of t en bilat eral. T he most c ommon CT appearanc e of renal ly mphoma in c hildhood is t hat of mult iple bilat eral nodules, oc c urring in approximat ely 70% of c ases (F ig. 24- 45A), f ollow ed in f requenc y by direc t inv asion f rom c ont iguous ly mph node masses (20% of c ases) and solit ary nodules (10% of c ases) (F ig. 24- 45B) (36,103). T y pic ally , t he int rarenal t umors are hy podense relat iv e t o normal renal parenc hy ma and show minimal enhanc ement . T he CT appearanc e of solit ary renal ly mphoma is indist inguishable f rom t hat of ot her solid int rarenal masses, but t he diagnosis is possible w hen t here is c oexist ing splenomegaly or w idespread ly mph node enlargement . On T 1- w eight ed MR images, ly mphomat ous nodes hav e a signal P.1752 int ensit y t hat is slight ly higher t han t hat of musc le and low er t han t hat of f at . On T 2- w eight ed images, t he signal int ensit y of ly mphomat ous nodes is equal t o or higher t han t hat of ret roperit oneal f at .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3608

24 - Pediatric Applications

F igure 24- 45 Renal ly mphoma. A: Comput ed t omography (CT ) sc an in a 1y ear- old boy show s bilat eral nephromegaly and renal masses. B: CT in a 14y ear- old boy show s a solit ary mass (M) in t he right kidney .

F igure 24- 46 Rhabdoid t umor. Comput ed t omography sc an t hrough t he upper abdomen demonst rat es an irregular, poorly def ined sof t t issue mass (M) replac ing t he parenc hy ma of t he lef t kidney . Also not ed is perirenal f luid (ar r ow s).

Rare Renal Tumors Clear c ell sarc oma and malignant rhabdoid t umor are rare pediat ric renal masses (6,30,40,90,251). T he f ormer t ends t o af f ec t c hildren bet w een 3 and 5 y ears of age, w hereas t he lat t er is more f requent in inf ant s, w it h a median age of 13 mont hs. Present ing signs are similar t o t hose of Wilms t umor. On CT and MRI, t hese t umors appear as solid int rarenal masses, replac ing or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3609

24 - Pediatric Applications

c ompressing t he remaining normal kidney . T he t umors may inv olv e one or bot h kidney s. Addit ional f indings inc lude renal c apsular t hic kening and subc apsular or perinephric f luid c ollec t ion w it h t umor implant s (6,40,90,251) (F ig. 24- 46). Conc omit ant primary t umors of t he post erior c ranial f ossa, sof t t issues, and t hy mus oc c ur in assoc iat ion w it h malignant rhabdoid t umor. Clear c ell sarc oma c ommonly met ast asizes t o bone. Renal c ell c arc inoma ac c ount s f or less t han 1% of pediat ric renal neoplasms. Mean age of present at ion of c hildren w it h renal c ell c arc inoma is approximat ely 9 y ears, in c ont rast t o Wilms t umor w it h a mean pat ient age at present at ion of 3 y ears. Present ing signs and sy mpt oms are nonspec if ic and inc lude mass, pain, and hemat uria. On CT and MRI, renal c ell c arc inoma is indist inguishable f rom Wilms t umor and appears as a solid int rarenal mass w it h ill- def ined margins (114) (F ig. 24- 47). Af t er t he int rav enous administ rat ion of c ont rast medium, t he mass enhanc es, but less t han t hat of t he surrounding normal renal parenc hy ma. Calc if ic at ion oc c urs in approximat ely 25% of t umors. Like Wilms t umor, renal c ell c arc inoma may spread t o ret roperit oneal ly mph nodes or may inv ade t he renal v ein and met ast asize t o lung and liv er.

F igure 24- 47 Renal c ell c arc inoma, 10- y ear- old boy . Cont rast - enhanc ed c omput ed t omography sc an demonst rat es a sof t t issue mass (M) in t he right kidney and a surrounding perirenal hemat oma. T he hemorrhage w as sec ondary t o t rauma and t umor rupt ure.

Renal medullary c arc inoma is an unusual t umor assoc iat ed w it h sic kle c ell t rait (47). Most pat ient s are diagnosed in t he sec ond or t hird dec ades of lif e. T he t umor is ext remely aggressiv e, arises c ent rally w it hin t he kidney , grow s in an

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3610

24 - Pediatric Applications inf ilt rat iv e pat t ern, and inv ades t he renal sinus. Cont rast enhanc ement is het erogeneous, ref lec t ing t umor nec rosis.

F igure 24- 48 Mult iloc ular c y st ic nephroma in a 4- y ear- old boy . Cont rast enhanc ed c omput ed t omography sc an show s a low - at t enuat ion mass c ont aining sev eral enhanc ing sept at ions in t he upper pole of t he lef t kidney .

F igure 24- 49 Aut osomal rec essiv e poly c y st ic disease and hepat ic f ibrosis. Cont rast - enhanc ed c omput ed t omography sc an show s mult iple, small renal c y st s. Splenomegaly (S) and hy pert rophy of t he lef t hepat ic lobe (L) sec ondary t o hepat ic f ibrosis are also not ed.

P.1753

Cystic Renal Masses

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3611

24 - Pediatric Applications Multilocular Cystic Nephroma Mult iloc ular c y st ic nephroma (also t ermed benign c y st ic nephroma, c y st ic

hamart oma, c y st ic ly mphangioma, and part ial poly c y st ic kidney ) is a unilat eral, nonheredit ary c y st ic mass. T he lesion has a biphasic age and sex dist ribut ion, af f ec t ing boy s under 4 y ears of age and w omen ov er 40 y ears of age. Present ing signs are a nonpainf ul abdominal mass or hemat uria. On CT and MRI, t he lesion appears as a w ell- def ined int rarenal mass w it h mult iple, w at erdensit y c y st s separat ed by sof t t issue sept a (7,97) (F ig. 24- 48). T he c y st ic spac es do not c ommunic at e w it h eac h ot her and do not enhanc e, but t he sept a are v asc ular and do enhanc e af t er int rav enous administ rat ion of c ont rast medium. Curv ilinear c alc if ic at ions may be seen w it hin t he w all or t he sept a.

Cystic Disease Renal c y st s in c hildren usually are bilat eral and f ound in assoc iat ion w it h heredit ary poly c y st ic disease and t uberous sc lerosis. Nonheredit ary simple c ort ic al c y st s are dist inc t ly unc ommon in c hildren. T he c linic al f eat ures of aut osomal rec essiv e poly c y st ic disease are dependent on t he age of present at ion. Inf ant s present w it h large kidney s, poor renal f unc t ion, and minimal hepat ic disease. In older c hildren, port al hy pert ension and esophageal v aric es sec ondary t o hepat ic f ibrosis predominat e. CT or MRI is done t o searc h f or c ollat eral v essels, absc ess, or hemorrhage. T he kidney s are enlarged w it h smoot h margins. T he c y st s, w hic h represent dilat ed t ubules, usually are c ent rally loc at ed and exhibit near- w at er at t enuat ion on CT (F ig. 24- 49), low signal int ensit y on T 1- w eight ed MR images, and high signal int ensit y on T 2w eight ed MR images (146). Some c y st s are hy perdense on CT and hy perint ense on T 1- w eight ed MR images, bec ause t he c ont ent s are muc oid or hemorrhagic . Dilat ed bile duc t s result ing f rom hepat ic f ibrosis also c an be seen on CT or MRI.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3612

24 - Pediatric Applications

F igure 24- 50 Angiomy olipomas in an adolesc ent boy w it h t uberous sc lerosis. Unenhanc ed c omput ed t omography sc an demonst rat es small masses of low at t enuat ion, approac hing f at densit y , in t he right kidney .

Aut osomal dominant poly c y st ic disease also has age- dependent c linic al f eat ures. Af f ec t ed neonat es hav e palpable abdominal masses, w hereas c hildren and adolesc ent s present w it h hy pert ension or hemat uria. In t he lat t er age groups, t he kidney s may be of normal size or enlarged and hav e lobulat ed or smoot h borders. T he c y st s are mult iple, unequal in size, and c ort ic al or medullary in loc at ion and hav e an at t enuat ion v alue and signal int ensit y similar t o t hose of c y st s elsew here in t he body . Assoc iat ed hepat ic , splenic , and panc reat ic c y st s also c an be ident if ied by CT or MRI.

Fatty Renal Masses Angiomyolipoma Angiomy olipoma is a benign renal t umor c omposed of angiomat ous, my omat ous, and lipomat ous t issue. It is rare as an isolat ed lesion in t he general pediat ric populat ion, but is present in as many as 80% of c hildren w it h t uberous sc lerosis. T he lesions usually are det ec t ed as an inc ident al f inding, but some pat ient s present w it h abdominal pain or anemia sec ondary t o int rat umoral or ret roperit oneal hemorrhage, or w it h renal f ailure bec ause of ext ensiv e parenc hy mal replac ement by t umor. On CT , t hese t umors are small, mult iple, bilat eral, and of low at t enuat ion, usually c ont aining at least some areas of ident if iable f at (F ig. 24- 50). Oc c asionally , t hey c oexist w it h c y st ic renal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3613

24 - Pediatric Applications

disease. Dif f erent iat ion w it h CT usually is possible based on dif f erenc es in t he at t enuat ion v alues of c y st ic and lipomat ous t issue. On MRI, angiomy olipomas demonst rat e high signal int ensit y on T 1- and T 2- w eight ed sequenc es and low signal int ensit y on f at - suppressed images.

F igure 24- 51 Neuroblast oma. A: Cont rast - enhanc ed c omput ed t omography (CT ) in a 2- y ear- old girl show s a suprarenal low - densit y mass displac ing t he right kidney (K) inf eriorly . T he inf erior v ena c av a (ar r ow ) is c ompressed and displac ed ant eriorly . T he t umor ext ends t o t he midline and abut s but does not displac e t he aort a. Also not ed is a small ret roperit oneal ly mph node (N). B: Coronal mult iplanar CT show s t he c ranioc audal ext ent of t he t umor.

P.1754

Adrenal Masses Hemorrhage Hemorrhage is t he most c ommon c ause of an adrenal mass in t he neonat e, oc c urring as a result of birt h t rauma, sept ic emia, or hy poxia. Adrenal hemorrhage is less f requent in inf ant s and c hildren and is usually t he result of t rauma (184,254). T he CT at t enuat ion v aries w it h t he age of t he hemat oma. Ac ut e hemat oma has a high at t enuat ion, w hereas subac ut e and c hronic hemat omas are of low at t enuat ion. T he signal c harac t erist ic s of t he blood v ary w it h t he age of t he hemorrhage. Ac ut e blood has a low signal int ensit y on T 1- w eight ed images and high signal int ensit y on T 2- w eight ed images. Subac ut e hemorrhage has high signal int ensit y on T 1- and T 2- w eight ed sequenc es. As t he blood c lot s and ly ses, t he int ensit y of t he hemorrhage

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3614

24 - Pediatric Applications dec reases ov er t ime. A c hronic hemat oma appears hy point ense on T 1w eight ed images and hy perint ense on T 2- w eight ed images. Neonat al neuroblast oma c an be hemorrhagic and, t hus, hav e an appearanc e similar t o t hat of benign hemorrhage. Dif f erent iat ing bet w een t hese t w o c ondit ions is possible w hen t here are hepat ic met ast ases or w hen serum

v anilly lmandelic ac id (VMA) lev els are elev at ed. Serial imaging also c an help t o dif f erent iat e bet w een t hese lesions. A hemat oma dec reases in size ov er 1 t o 2 w eeks, w hereas neuroblast oma eit her remains t he same size or enlarges.

Neuroblastoma Neuroblast oma is t he most c ommon malignant abdominal t umor in c hildren, usually af f ec t ing c hildren under t he age of 4 y ears. More t han half of all neuroblast omas originat e in t he abdomen, and t w o t hirds of t hese arise in t he adrenal gland (1,29,147). T he ext ra- adrenal t umors originat e in t he sy mpat het ic ganglion c ells or para- aort ic bodies and may be f ound any w here f rom t he c erv ic al region t o t he pelv is. Neuroblast oma t ends t o met ast asize early and more t han half of all pat ient s hav e bone marrow , skelet al, liv er, or skin met ast ases w hen init ially diagnosed. Lung met ast ases are rare. On CT , neuroblast oma appears as a homogeneous or het erogeneous, pararenal or paraspinal, sof t t issue mass w it h lobulat ed margins (1,147,227,284). T he t umor enhanc es less t han t hat of surrounding t issues af t er int rav enous administ rat ion of c ont rast mat erial (F ig. 24- 51). Calc if ic at ions w it hin t he t umor, w hic h may be c oarse, mot t led, solid, or ring- shaped, are observ ed in approximat ely 85% of neuroblast omas on CT . On T 1- w eight ed MR images, neuroblast oma appears eit her hy point ense or isoint ense relat iv e t o t he liv er. On T 2- w eight ed and gadolinium- enhanc ed sequenc es, it appears slight ly t o markedly hy perint ense relat iv e t o liv er (F ig. 24- 52). T he c ent er of t he t umor is of t en het erogeneous, ref lec t ing t he presenc e of hemorrhage, nec rosis, or c alc if ic at ion. Hemorrhage may appear as a low or high signal int ensit y f oc us on T 1- w eight ed pulse sequenc es, depending on t he age of t he blood; it usually has high signal int ensit y on T 2w eight ed images. F oc al nec rosis produc es signal hy point ensit y on T 1- w eight ed images and hy perint ensit y on T 2- w eight ed sequenc es. Calc if ic at ions are hy point ense on all sequenc es (1,24,147,238,239,284). F indings of loc al spread, suc h as prev ert ebral ext ension ac ross t he midline (F ig. 24- 53), v asc ular enc asement (F ig. 24- 53), hepat ic met ast ases, int raspinal ext ension (F ig. 24- 54), and renal inv asion or inf arc t ion, c an be seen on bot h CT and

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3615

24 - Pediatric Applications

MRI. CT and MRI c an also show skelet al inv olv ement (209,221,260). Know ledge of t umor ext ent is import ant f or underst anding t he many appearanc es of neuroblast oma, f or t reat ment planning, and f or prognosis. F ollow ing surgery or c hemot herapy , CT or MRI may be used t o monit or t reat ment response and det ec t rec urrent disease. Serial CT examinat ions af t er t herapy of t en suf f ic e t o det ermine t he adequac y of t reat ment . In pat ient s w it h residual masses, MRI and F DG- PET imaging may be able P.1755 t o separat e f ibrosis and t umor inv olv ement . Demonst rat ion of a residual mass w it h low signal int ensit y on bot h T 1- and T 2- w eight ed images f av ors t he diagnosis of f ibrosis, w hereas high signal on t he T 2- w eight ed sequenc e suggest s residual t umor.

F igure 24- 52 Neuroblast oma. A: T 1- w eight ed c oronal magnet ic resonanc e (MR) image in a 3- y ear- old girl show s a large lef t suprarenal t umor (T ). T he area of relat iv ely high signal int ensit y w it hin t he t umor represent s hemorrhage. B: T 1- w eight ed MR image af t er gadolinium c helat e administ rat ion show s het erogeneous enhanc ement .

Adrenocortical Neoplasms Adrenal lesions, ot her t han neuroblast omas, are rare in c hildhood, ac c ount ing f or 5% or less of all adrenal t umors (1,198). Of t hese, c arc inoma is t he most c ommon, f ollow ed in f requenc y by adenoma. T he mean ages at present at ion of pat ient s w it h c arc inoma and adenoma are approximat ely 6 y ears and 3 y ears, respec t iv ely . Adrenal c arc inomas are usually hormonally ac t iv e, produc ing

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3616

24 - Pediatric Applications v irilizat ion, f eminizat ion, or Cushing sy ndrome. Adenomas c an c ause Cushing sy ndrome or primary aldost eronism, but t hey also may be det ec t ed inc ident ally .

F igure 24- 53 Neuroblast oma w it h midline ext ension. Cont rast - enhanc ed c omput ed t omography sc an demonst rat es ext ension of t umor, w it h c alc if ic at ions ant erior t o t he v ert ebral body and w it h enc asement of t he lef t renal art ery (ar r ow ) and aort a (A). T here is mild lef t hy dronephrosis.

Adrenal c arc inomas are t y pic ally large masses at t he t ime of present at ion, of t en great er t han 4 c m in diamet er, w it h an at t enuat ion v alue equal t o t hat of sof t t issue (F ig. 24- 55). Many c ont ain low - densit y areas f rom prior hemorrhage and nec rosis; some c ont ain c alc if ic at ions. Cort isol- produc ing adenomas range bet w een 2 and 5 c m in diamet er, w hereas aldost eronesec ret ing t umors are usually less t han 2 c m in diamet er. Bot h t y pes of adenomas t end t o be homogeneous and of low at t enuat ion bec ause of t heir high lipid c ont ent (227). Carc inomas exhibit a low signal int ensit y on T 1w eight ed MR images and high signal int ensit y on T 2- w eight ed MR images. Adenomas may hav e a high signal int ensit y on bot h pulse sequenc es.

Pheochromocytoma Pheoc hromoc y t omas are c at ec holamine- produc ing t umors t hat c ause paroxy smal hy pert ension in c hildren (1,284). Most pheoc hromoc y t omas in c hildren are sporadic ; how ev er, t hey may be assoc iat ed w it h mult iple endoc rine neoplast ic (MEN) sy ndromes and t he phakomat oses, inc luding neurof ibromat osis, t uberous sc lerosis, v on Hippel- Lindau disease, and St urgeWeber disease. Approximat ely 75% of c hildhood pheoc hromoc y t omas arise

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3617

24 - Pediatric Applications P.1756 in t he adrenal medulla; t he remainder are ext ra- adrenal, oc c urring in t he sy mpat het ic ganglia adjac ent t o t he v ena c av a or aort a, near t he organ of Zuc kerkandl, or in t he w all of t he urinary bladder. Up t o 70% of t umors are bilat eral and about 5% t o 10% are malignant . Most are at least 3 c m in diamet er at t he t ime of diagnosis. On CT , pheoc hromoc y t omas are of sof t t issue densit y and f requent ly enhanc e af t er int rav enous administ rat ion of

c ont rast medium (F ig. 24- 56A). On T 1- w eight ed MR images, t hey hav e a signal int ensit y similar t o t hat of musc le; on T 2- w eight ed images, t he signal int ensit y is equal t o or great er t han t hat of f at (F ig. 24- 56B). Small pheoc hromoc y t omas of t en are homogeneous, w hereas larger t umors appear het erogeneous w it h bot h c y st ic and solid c omponent s. Calc if ic at ions w it hin t he t umor are rare.

F igure 24- 54 Neuroblast oma w it h int raspinal inv asion. Sagit t al t urbo- spinec ho T 2- w eight ed image show s a large int ermediat e signal int ensit y pelv ic mass (M) inv ading t he spinal c anal (ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3618

24 - Pediatric Applications

F igure 24- 55 Adrenal c arc inoma in a 9- y ear- old girl w it h v irilizat ion. A large sof t t issue mass is present in t he right adrenal gland.

Retroperitoneal Soft Tissue Masses Alt hough rare, bot h benign and malignant primary t umors oc c ur in t he ret roperit oneal sof t t issues. Benign t umors inc lude t erat oma, ly mphangioma, neurof ibroma, and lipomat osis. T erat omas appear as w ell- def ined, f luid- f illed masses w it h a v ariable amount of f at or c alc ium (F ig. 24- 57). Ly mphangiomas are w ell- c irc umsc ribed, mult iloc ulat ed f luid- f illed masses. Neurof ibromas are usually w ell- def ined, c y lindric al, sof t t issue lesions w it h a c harac t erist ic loc at ion in t he neurov asc ular bundle. Lipomat osis appears as a dif f use, inf ilt rat iv e mass w it h an at t enuat ion v alue or signal int ensit y equal t o t hat of f at ; it grow s along f asc ial planes and may inv ade musc le. Rhabdomy osarc oma is t he most c ommon malignant t umor of t he ret roperit oneum, f ollow ed by neurof ibrosarc oma, f ibrosarc oma, and ext ragonadal germ c ell t umors. T hese t umors appear as bulky sof t t issue masses w it h at t enuat ion v alues slight ly less t han or equal t o t hat of musc le. On T 1- w eight ed MR images, t hey appear eit her hy po- or isoint ense t o liv er, kidney , and musc le. On T 2- w eight ed images, rhabdomy osarc oma has a signal int ensit y equal t o or great er t han t hat of f at . Vessel displac ement or enc asement somet imes oc c urs and c an be seen easily w it h GRE imaging (214).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3619

24 - Pediatric Applications Hepatic Masses Primary Malignant Neoplasms Primary hepat ic t umor is t he t hird most f requent solid abdominal mass in c hildren, f ollow ing Wilms t umor and neuroblast oma. T w o t hirds of hepat ic t umors are malignant , w it h hepat oblast oma and hepat oc ellular c arc inoma ac c ount ing f or t he majorit y (34,79). T he f ormer oc c urs in c hildren under t he age of 3 y ears, w hereas t he lat t er is more f requent in older c hildren. T he t umors are disc ov ered as asy mpt omat ic upper abdominal masses, oc c asionally assoc iat ed w it h anorexia and w eight loss.

At gross examinat ion, hepat oblast oma c ont ains small, primit iv e epit helial c ells, resembling f et al liv er. Hepat oc ellular c arc inoma c ont ains large, pleomorphic mult inuc leat ed c ells w it h v ariable degrees of dif f erent iat ion (34,79). Inv asion of t he port al or hepat ic v eins is f requent in bot h t umors. T he CT appearanc es of hepat oblast oma and hepat oc ellular c arc inoma are similar. Bot h t umors usually are c onf ined t o a single lobe, w it h t he right lobe af f ec t ed t w ic e as of t en as t he lef t , but t hey may inv olv e bot h lobes or t hey may be mult ic ent ric . T hey generally hav e a densit y equal P.1757 t o or low er t han t hat of normal hepat ic parenc hy ma on unenhanc ed sc ans (46,52,100,107,191,233). On art erial phase imaging, t hey enhanc e more t han adjac ent normal liv er (F ig. 24- 58). T hey bec ome hy point ense t o liv er on port al v enous phase imaging. Bot h t umors of t en are het erogeneous bec ause t hey c ont ain hemorrhage, nec rosis, or f oc al st eat osis. Calc if ic at ions oc c ur in approximat ely 50% of hepat oblast omas and in 25% of hepat oc ellular c arc inomas. T umor t hrombus appears as a low - at t enuat ion area w it hin t he port al or hepat ic v eins.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3620

24 - Pediatric Applications

F igure 24- 56 Adrenal pheoc hromoc y t omas. A: Cont rast - enhanc ed c omput ed t omography sc an show s a lef t adrenal mass (ar r ow s) w it h c ent ral nec rosis. T he sof t t issue c omponent s show moderat e enhanc ement . B: F at - sat urat ed T 2- w eight ed magnet ic resonanc e image in anot her pat ient show s high signal int ensit y mass (ar r ow ) in t he right adrenal gland.

Malignant hepat ic lesions are hy point ense w it h respec t t o liv er on T 1w eight ed MR images and hy perint ense on T 2- w eight ed sequenc es (52,191,192,223). On gadolinium- enhanc ed images, bot h hepat oblast oma and hepat oc ellular c arc inoma demonst rat e dif f use, het erogeneous enhanc ement (F ig. 24- 59). T umor t hrombus is seen as a hy perint ense f oc us w it hin a normally signal- f ree v essel on spin- ec ho images or as a hy point ense area on GRE imaging (F ig. 24- 60). Hemorrhage c an appear hy po- or hy perint ense on T 1- w eight ed pulse sequenc es, depending on t he P.1758 age of t he blood; it usually is hy perint ense on T 2- w eight ed images. F oc al st eat osis produc es signal hy perint ensit y on bot h T 1- and T 2- w eight ed pulse sequenc es and low signal int ensit y on f at - suppressed images. Calc if ic at ions are hy point ense on all sequenc es.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3621

24 - Pediatric Applications

F igure 24- 57 Ret roperit oneal t erat oma. Cont rast - enhanc ed c omput ed t omography sc an demonst rat es a large predominant ly f luid- f illed mass c ont aining areas of f at and c alc if ic at ion.

F igure 24- 58 Hepat oblast oma in a 2- y ear- old girl w it h a right upper quadrant mass. Art erial phase c omput ed t omography image obt ained 12 sec onds af t er t he st art of c ont rast administ rat ion show s a large, het erogeneously enhanc ing sof t t issue t umor (T ) oc c upy ing t he post erior right lobe of t he liv er and a smaller homogeneous mass (ar r ow s) in t he medial segment of t he lef t lobe.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3622

24 - Pediatric Applications

F igure 24- 59 Hepat oblast oma, 7- y ear- old boy . A: Gadolinium- enhanc ed T 1w eight ed axial magnet ic resonanc e (MR) image w it h f at sat urat ion show s a large, het erogeneously enhanc ing t umor replac ing most of t he upper abdomen. B: MR angiogram show s a large hepat ic art ery (ar r ow ) f eeding t he t umor. (Case c ourt esy of F red Hof f er, MD, Memphis, T N.)

F ibrolamellar hepat oc ellular c arc inoma, w hic h is a subt y pe of hepat oc ellular c arc inoma, is a rare malignant t umor in c hildren and adolesc ent s. T he prognosis f or pat ient s w it h unresec t able t umor is bet t er t han t hat f or pat ient s w it h t he usual v ariet y of hepat oc ellular c arc inoma (av erage surv iv al, 32 and 6 mont hs, respec t iv ely ). On CT and MRI, f ibrolamellar hepat oc ellular c arc inoma is usually solit ary and w ell delineat ed w it h v ariable c ont rast enhanc ement . Small c ent ral c alc if ic at ions are seen in about 40% of t umors and a c ent ral sc ar in 30% (104,158,265). T he imaging f eat ures of f ibrolamellar c arc inoma are similar t o t hose of t he ot her malignant hepat ic t umors, and so biopsy is needed f or def init iv e diagnosis.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3623

24 - Pediatric Applications

F igure 24- 60 Hepat oblast oma in a 3- y ear- old boy . T 2- w eight ed image show s a high signal int ensit y t umor (T ) in t he lat eral segment of t he lef t lobe of t he liv er and in t he right (R) and main port al v ein (PV).

Undif f erent iat ed embry onal sarc oma, also know n as mesenc hy mal sarc oma, embry onal sarc oma, and malignant mesenc hy moma, is t he t hird most c ommon primary malignant t umor in c hildren af t er hepat oblast oma and hepat oc ellular c arc inoma. It primarily af f ec t s older c hildren and adolesc ent s. T he usual present ing f eat ures are abdominal mass and pain. On CT , t he t umor is a hy podense mult iloc ular mass w it h mult iple sept at ions and a t hic k peripheral rim, w hic h may enhanc e af t er injec t ion of c ont rast medium (32,183) (F ig. 2461). T he MRI appearanc e is t hat P.1759 of a het erogeneous, sept at ed mass w it h predominant ly hy point ense c ont ent s on T 1- w eight ed images and hy perint ense c ont ent s on T 2- w eight ed images. T he f ibrous rim has low signal int ensit y on bot h imaging sequenc es. Af t er gadolinium administ rat ion, t he solid areas enhanc e, w hereas t he c y st ic spac es remain hy point ense.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3624

24 - Pediatric Applications

F igure 24- 61 Undif f erent iat ed embry onal sarc oma in a 9- y ear- old boy . Cont rast - enhanc ed c omput ed t omography show s a predominant ly c y st ic mass (M) w it h sev eral t hin sept at ions.

F igure 24- 62 Hepat ic met ast ases in a neonat e w it h neuroblast oma. Cont rast enhanc ed c omput ed t omography sc an show s mult iple low - densit y hepat ic met ast ases and bilat eral pleural ef f usions.

Hepatic Metastases T he malignant t umors of c hildhood t hat most f requent ly met ast asize t o t he liv er are Wilms t umor, neuroblast oma, and ly mphoma. Clinic ally , pat ient s w it h hepat ic met ast ases present w it h hepat omegaly , jaundic e, abdominal pain or mass, or abnormal hepat ic f unc t ion t est s.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3625

24 - Pediatric Applications Hepat ic met ast ases are t y pic ally mult iple, hy podense relat iv e t o normal liv er on c ont rast - enhanc ed CT (F ig. 24- 62), hy point ense on T 1- w eight ed images,

and hy perint ense on T 2- w eight ed images. Alt hough t he signal int ensit y is high on T 2- w eight ed images, it is not as high as t hat seen w it h hemangiomas or c y st s. Ot her f indings inc lude c ent ral nec rosis and mass ef f ec t w it h displac ement of v essels. Hepat ic met ast ases in c hildren may exhibit some degree of het erogeneous c ent ral enhanc ement on post c ont rast images.

Benign Neoplasms Benign t umors ac c ount f or about one t hird of all hepat ic t umors in c hildren. T he majorit y are of v asc ular origin and usually hemangioendot heliomas (34). Most pat ient s w it h hemangioendot heliomas are under 6 mont hs of age and present w it h hepat omegaly or c ongest iv e heart f ailure bec ause of high- out put ov erc irc ulat ion. Oc c asionally , af f ec t ed pat ient s present w it h bleeding diat hesis sec ondary t o plat elet sequest rat ion (Kasabac h- Merrit t sy ndrome) or massiv e hemoperit oneum result ing f rom spont aneous t umor rupt ure. By c omparison w it h adult s, c av ernous hemangioma is inf requent ly f ound in c hildren, alt hough it is somet imes enc ount ered as an inc ident al f inding.

F igure 24- 63 Mult iple hemangioendot heliomas in a new born girl. T 2- w eight ed spin- ec ho image show s mult iple lesions t hat are markedly hy perint ense t o normal liv er parenc hy ma. (Court esy of Sudha Appunirni, MD, Bost on, MA.)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3626

24 - Pediatric Applications On gross examinat ion, hemangioendot helioma is a relat iv ely bloodless t umor c omposed of mult iple nodules ranging f rom 2 t o 15 c m in diamet er (34). Hist ologic ally , it is c omposed of v asc ular c hannels lined by plump endot helial c ells t hat are support ed by ret ic ular f ibers. T he t umor is usually solit ary and

has a slight predilec t ion f or t he post erior segment of t he right lobe, but it may be mult ic ent ric and inv olv e bot h lobes. Areas of f ibrosis, c alc if ic at ion, hemorrhage, and c y st ic degenerat ion are f requent . Hemangioendot helioma and c av ernous hemangioma hav e similar appearanc es on CT and MRI. On non–c ont rast - enhanc ed CT , bot h lesions are hy poat t enuat ing relat iv e t o t he liv er and bot h are hy point ense on T 1- w eight ed MR images (52,107,121,191,223,233). On T 2- w eight ed images, t he lesions are hy perint ense (F ig. 24- 63). A het erogeneous appearanc e may be not ed bec ause of areas of f ibrosis, nec rosis, or hemorrhage. Images af t er administ rat ion of iodinat ed c ont rast medium or gadolinium c helat es demonst rat e c ent ripet al enhanc ement w it h v ariable degrees of delay ed c ent ral enhanc ement (F ig. 24- 64) (175,223,233). Small t umors may rapidly bec ome hy perdense w it hout show ing peripheral enhanc ement . Larger lesions, part ic ularly solit ary lesions, may not c omplet ely enhanc e on delay ed sc ans (51), ref lec t ing areas of f ibrosis or t hrombosis.

F igure 24- 64 Dif f use hemangioendot heliomat osis in a neonat e. A: Art erial phase c omput ed t omography (CT ) image obt ained 12 sec onds af t er t he st art of c ont rast administ rat ion demonst rat es mult iple high- at t enuat ion lesions in t he liv er. B: Port al v enous phase CT sc an obt ained 50 sec onds af t er injec t ion of c ont rast medium demonst rat es nearly c omplet e w ashout of t he lesions.

P.1760

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3627

24 - Pediatric Applications Af t er t he v asc ular lesions, mesenc hy mal hamart oma is t he next most c ommon benign hepat ic t umor of c hildhood. It is t he benign c ount erpart t o t he undif f erent iat ed embry onal sarc oma. T his t umor usually is f ound as an

asy mpt omat ic mass in boy s under 2 y ears of age. Rarely , t he hamart oma has a large v asc ular c omponent and produc es art eriov enous shunt ing, leading t o c ongest iv e heart f ailure. On CT , t he lesion appears as a w ell- c irc umsc ribed mult iloc ular mass c ont aining mult iple low - densit y areas separat ed by solid t issue (F ig. 24- 65) (52,107,191,233). Af t er int rav enous administ rat ion of c ont rast medium, t he c ent ral c ont ent s do not enhanc e, but t he t hic ker sept a may inc rease in at t enuat ion. T 1- w eight ed MR images show a low - int ensit y mass; T 2- w eight ed images demonst rat e a hy perint ense mass c ont aining sept at ions of low signal int ensit y (192,223). Dif f erent iat ion bet w een mesenc hy mal hamart oma and undif f erent iat ed embry onal sarc oma by imaging f indings is dif f ic ult . A y ounger age and absenc e of sy mpt oms f av ors a benign hamart oma, but def init iv e diagnosis requires t issue sampling.

F igure 24- 65 Mesenc hy mal hamart oma. Comput ed t omography image during t he port al v enous phase show s a w ell- c irc umsc ribed mass c ont aining low at t enuat ion loc ules separat ed by sof t t issue sept at ions. (Court esy of James Mey er, MD, Philadelphia, PA)

Biliary Masses Choledoc hal c y st is t he most c ommon mass arising in t he biliary duc t al t ree (212). Classic ally , pat ient s present w it h jaundic e, pain, and a palpable abdominal mass, alt hough t he c omplet e t riad is present in only about one t hird

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3628

24 - Pediatric Applications of pat ient s. T he diagnosis usually c an be made by sonography . CT and MR c holangiography hav e prov ed t o be usef ul, noninv asiv e alt ernat iv es t o

endosc opic ret rograde panc reat ography t o delineat e t he anat omy of t he biliary sy st em w hen t he result s of ot her st udies are indet erminat e or addit ional inf ormat ion is needed f or surgic al planning (105,123,171) (F igs. 24- 66 and 2467). T he int rahepat ic dilat at ion is limit ed t o t he c ent ral port ions of t he lef t and right hepat ic duc t s. Generalized duc t al dilat at ion, w it h gradual t apering t o t he periphery , c harac t erist ic of ac quired obst ruc t ion, is absent . Rhabdomy osarc oma of t he biliary t rac t is rare, but it is t he most c ommon malignant neoplasm of t he biliary t rac t in c hildren. Most biliary t rac t rhabdomy osarc omas arise in t he port a hepat is and inv olv e t he c y st ic duc t . Imaging f indings are int ra- and ext rahepat ic duc t al dilat at ion and a mass in t he port a hepat is (200,211). P.1761

Pancreatic Masses F oc al panc reat ic lesions in c hildren are usually exoc rine neoplasms or c y st ic lesions. Panc reat ic oblast oma is t he most c ommon exoc rine panc reat ic neoplasm in y oung c hildren. It is an enc apsulat ed, epit helial t umor c omposed of t issue resembling f et al panc reas, has a f av orable prognosis, and usually arises in t he panc reat ic head. On c ont rast - enhanc ed CT , t he t umor appears as a f oc al mass of homogeneous or het erogeneous sof t t issue densit y (81,92,150) (F ig. 24- 68). Sec ondary signs inc lude hepat ic and ly mph node met ast ases and v asc ular enc asement . Solid and papillary epit helial neoplasm of t he panc reas is t he most c ommon exoc rine t umor in adolesc ent s, usually af f ec t ing f emales more t han males (31,92,278). T he t umor has a low pot ent ial f or malignanc y , is w ell enc apsulat ed, and usually oc c urs in t he t ail. On CT , t his neoplasm appears as a large (mean 11.5 c m), w ell- def ined, t hic k- w alled c y st ic mass c ont aining papillary projec t ions and oc c asionally sept a.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3629

24 - Pediatric Applications

F igure 24- 66 Choledoc hal c y st , 13- y ear- old girl w it h abdominal pain. A: Post c ont rast c omput ed t omography (CT ) sc an demonst rat es mildly dilat ed right (blac k ar r ow ) and lef t (w hit e ar r ow ) hepat ic duc t s. T he peripheral branc hes are not dilat ed. B: CT image 4 c m c audal show s a dilat ed c ommon bile duc t (CBD), represent ing t he c holedoc hal c y st , separat e f rom t he gallbladder (GB). C : Coronal mult iplanar ref ormat t ed image show s t he relat ionship of t he c y st (C) t o t he port al v ein (PV).

Cy st ic lesions are usually assoc iat ed w it h inherit ed disorders inc luding c y st ic f ibrosis, v on Hippel- Lindau disease, and aut osomal dominant poly c y st ic disease. T he c y st s in c y st ic f ibrosis are believ ed t o be t he result of inspissat ed sec ret ions leading t o duc t al dilat at ion.

Splenic Masses F oc al splenic lesions in c hildren inc lude absc esses, neoplasms (most c ommonly ly mphoma and rarely hamart oma), v asc ular malf ormat ions (ly mphangioma, hemangioma), and c y st s (246). Absc esses, v asc ular malf ormat ions, and c y st s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3630

24 - Pediatric Applications

hav e a low at t enuat ion v alue on CT , a low signal int ensit y on T 1- w eight ed MR images, and a signal int ensit y great er t han t hat of f at on T 2- w eight ed images (275,280). Solid t umors are of sof t t issue densit y on P.1762 CT and hav e int ermediat e signal int ensit y on T 1- w eight ed images and high signal int ensit y on T 2- w eight ed images (F ig. 24- 69). On MRI, t hey show a signal int ensit y great er t han t hat of musc le and less t han t hat of f at on T 1w eight ed images, and a signal int ensit y nearly equal t o t hat of f at on T 2w eight ed sequenc es. Vasc ular malf ormat ions enhanc e af t er int rav enous c ont rast medium administ rat ion (62).

F igure 24- 67 Choledoc hal c y st in a 2- y ear- old boy w it h jaundic e. Coronal f at - suppressed t urbo T 2- w eight ed image demonst rat es a high- signal int ensit y c y st (C) in t he port a hepat is separat e f rom t he gallbladder (g). (Court esy of Pet er St rouse, MD, Ann Arbor, MI.)

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3631

24 - Pediatric Applications

F igure 24- 68 Panc reat ic oblast oma in a 3- y ear- old girl w it h a lef t upper quadrant mass. A 7- c m, het erogeneous mass is present in t he t ail of t he panc reas. Low - densit y areas represent nec rosis.

In some c hildren, t he spleen is highly mobile bec ause of t he f ailure of f usion of t he gast ric mesent ery w it h t he dorsal perit oneum, and present s as a mass in t he ant erior abdomen. CT or MRI demonst rat es absenc e of t he spleen in t he lef t upper quadrant and a low er abdominal or pelv ic sof t t issue mass. T he mobile spleen enhanc es af t er administ rat ion of int rav enous c ont rast medium unless it has undergone t orsion w it h result ant v asc ular c ompromise (91).

Gastrointestinal and Mesenteric Masses Ly mphangiomat ous malf ormat ions, also t ermed mesent eric c y st s, and ent eric duplic at ions ac c ount f or most benign gast roint est inal/mesent eric masses (208,246). On CT , a mesent eric c y st is a near- w at er densit y mass w it h a barely disc ernible w all (F ig. 24- 70), w hereas an ent eric duplic at ion appears as a c y st ic mass w it h a t hic k w all (155,208,246,266). Bot h lesions hav e a signal int ensit y equal t o or slight ly less t han t hat of musc le on T 1- w eight ed MR images, alt hough t he signal int ensit y may be higher if t he lesions c ont ain blood or prot einac eous mat erial. On T 2- w eight ed images, t he signal int ensit y is great er t han t hat of f at . Ly mphoma is t he most c ommon malignant neoplasm of t he bow el and mesent ery . T he CT f eat ures of bow el ly mphoma inc lude bow el w all–t hic kening great er t han 1 c m in diamet er, ext raluminal sof t t issue mass, and mesent eric inv asion. T he CT f eat ures of mesent eric inv olv ement by ly mphoma range f rom mult iple small sof t t issue masses t o a large sof t t issue

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3632

24 - Pediatric Applications mass displac ing adjac ent st ruc t ures (F ig. 24- 71). On MRI, ly mphomat ous masses hav e a signal int ensit y similar t o t hat of musc le on T 1- w eight ed images and similar t o t hat of f at on T 2- w eight ed sequenc es.

Lymphoma Int ra- abdominal ly mphoma most of t en af f ec t s t he ret roperit oneal and mesent eric ly mph nodes, bow el, and mesent ery . Alt hough CT and MRI oc c asionally demonst rat e normal- size ly mph nodes in t he ret roperit oneum and pelv is in t he adult , t hese are rarely rec ognized in c hildren. How ev er, ly mphoma and met ast at ic disease of any c ause may produc e suf f ic ient ly mph node enlargement t o be demonst rable on CT and MRI. T he CT appearanc e of suc h ly mphadenopat hy v aries f rom indiv idually enlarged ly mph nodes of sof t t issue densit y t o a large mass obsc uring normal st ruc t ures (F ig. 24- 71). On MRI, ly mph nodes inv olv ed by ly mphoma hav e a signal int ensit y great er t han or equal t o t hat of musc le on T 1- w eight ed images and c lose t o t hat of f at on T 2- w eight ed sequenc es. As in t he adult , t hese imaging st udies c annot dif f erent iat e normal ly mph nodes f rom nodes t hat are of normal size but replac ed w it h t umor. In addit ion, it is impossible t o dist inguish bet w een mild enlargement of ly mph nodes result ing f rom inf lammat ory c ondit ions, suc h as Crohn disease, giardiasis, t uberc ulosis, sarc oidosis, and ac quired immune def ic ienc y sy ndrome, and enlargement result ing f rom neoplast ic inv olv ement .

F igure 24- 69 Splenic masses. A: Hodgkin ly mphoma. Cont rast - enhanc ed c omput ed t omography show s mult iple low - at t enuat ion masses in t he spleen. Also not ed is mesent eric (blac k ar r ow ) and ret roc rural (w hit e ar r ow ) ly mphadenopat hy . B: Hamart oma. T 2- w eight ed image show s high signal int ensit y mass (M) in t he medial part of t he spleen.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3633

24 - Pediatric Applications P.1763 Rarely , rhabdomy osarc oma is a c ause of int raperit oneal nodal masses. T he CT and MR appearanc es are similar t o t hose of ly mphoma (39).

Abdominal Abscess Most abdominal absc esses in c hildren are c aused by appendic it is, Crohn disease, and/or post operat iv e c omplic at ions. T he t y pic al CT appearanc e of an absc ess is t hat of a mass of relat iv ely low densit y , w it h or w it hout a rim t hat of t en is enhanc ed af t er int rav enous administ rat ion of c ont rast mat erial (F ig. 24- 72). Gas is present in slight ly more t han one t hird of absc esses and may appear as mult iple small bubbles or as a large c ollec t ion w it h an air–f luid lev el. T he size and shape are af f ec t ed by loc at ion, bec ause absc esses usually are c onf ined t o f asc ial or int raperit oneal c ompart ment s, expanding t he spac es and displac ing c ont iguous st ruc t ures. Absc esses c ommonly produc e oblit erat ion of adjac ent f at planes and t hic kening of surrounding musc les, mesent ery , or bow el w all.

F igure 24- 70 Mesent eric c y st , 15- y ear- old girl. A w ell- def ined, low - densit y mass (M), c ont aining sev eral t hin sept at ions, is not ed in t he low er pelv is. T he lesion inv olv ed t he small bow el mesent ery .

Blunt Abdominal Trauma Abdominal injuries in c hildren are most of t en t he result of blunt t rauma c aused by mot or v ehic le ac c ident s and less f requent ly c aused by bic y c le, skat eboard,

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3634

24 - Pediatric Applications and all- t errain v ehic le ac c ident s, f alls, gunshot injuries, and c hild abuse (248,250). CT is employ ed as t he init ial imaging proc edure f or sev erely t raumat ized c hildren w hose v it al signs are st able enough t o permit t he examinat ion. CT prov ides P.1764 a radiologic display of t he ent ire abdomen f ollow ing nonpenet rat ing injuries and c an doc ument injury t o bot h solid and hollow organs, int raperit oneal or

ret roperit oneal hemorrhage, sit es of ac t iv e bleeding, and unsuspec t ed t horac ic or skelet al injuries (271,272). Unst able pediat ric pat ient s generally proc eed direc t ly t o surgery w it hout imaging examinat ions.

F igure 24- 71 Mesent eric ly mphoma, 12- y ear- old boy . A large c onglomerat e mesent eric mass of ly mphomat ous nodes, some w it h nec rosis, ext ends f rom t he ant erior abdominal w all t o t he ret roperit oneum.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3635

24 - Pediatric Applications

F igure 24- 72 Appendic eal absc ess. Cont rast - enhanc ed c omput ed t omography demonst rat es a low - at t enuat ion bilobed mass w it h small air bubbles and an air–f luid lev el in t he low er pelv is. T he mass is part ially surrounded by an enhanc ing rim (ar r ow s) and st reaky sof t t issue densit ies ext ending int o t he adjac ent pelv ic f at .

F igure 24- 73 Liv er f rac t ure w it h hy pov olemic shoc k. A: Comput ed t omography (CT ) image t hrough t he upper abdomen show s a deep parenc hy mal lac erat ion ext ending t hrough t he right hepat ic lobe, result ing in an av ulsed, nonperf used post erior segment (ar r ow s). High- at t enuat ion ext rav asat ed c ont rast mat erial represent ing ac t iv e hemorrhage is ev ident at t he f rac t ure sit e. T he dec reased splenic enhanc ement is relat ed t o t he hy pot ension and should not be misint erpret ed as represent ing splenic injury . B: A more c audal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3636

24 - Pediatric Applications

CT image rev eals blood in t he perihepat ic and perisplenic spac es, dilat ed small bow el loops w it h int ensely enhanc ing w alls, a small aort a (blac k ar r ow ) and inf erior v ena c av a (w hit e ar r ow ), indic at ing hy pov olemic shoc k.

F igure 24- 74 Subc apsular splenic hemat oma. A low - at t enuat ion lent ic ularshaped subc apsular hemat oma (ar r ow s) f lat t ens t he lat eral splenic c ont our. T he pat ient had a small splenic lac erat ion, seen on ot her lev els.

T he CT appearanc e of int ra- abdominal injuries depends on w het her t he injury is t o a solid or hollow organ. T he liv er is t he most c ommonly injured abdominal organ, f ollow ed by t he spleen, kidney , adrenal gland, and panc reas. T he spec t rum of injuries in solid organs ranges f rom small int raparenc hy mal and subc apsular hemat omas t o large lac erat ions or f rac t ures w it h c apsular disrupt ion (15,119,231). T y pic ally , int raparenc hy mal hemat omas appear on CT as round or ov al f luid c ollec t ions. F rac t ures and lac erat ions P.1765 appear as irregular, linear areas of low densit y w it hin an organ (F ig. 24- 73). Subc apsular hemat omas are lent ic ular or ov al in c onf igurat ion and f lat t en or indent t he underly ing parenc hy ma (F ig. 24- 74). Ac ut e blood generally has a densit y low er t han t hat of surrounding t issue on c ont rast - enhanc ed CT images. Ot her CT f indings report ed w it h hepat ic injuries inc lude subc apsular or int raparenc hy mal gas, result ing f rom ac ut e t issue nec rosis, and periport al areas of low at t enuat ion. Periport al low - at t enuat ion zones, presumably represent ing edema, hav e been not ed in 65% of c hildren w it h blunt abdominal t rauma, and in 30% of pat ient s t hey are t he only CT abnormalit y (219). Int ra- or ext raperit oneal f luid may be seen w it h f rac t ures or lac erat ions ext ending t o t he surf ac e of an organ (255). In f ac t , a loc alized f luid c ollec t ion

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3637

24 - Pediatric Applications may be more readily apprec iat ed t han t he underly ing parenc hy mal injury , and t hus may be a radiologic c lue t o t he diagnosis (255). A large int raperit oneal

f luid c ollec t ion suggest s a more sev ere injury . F luid c ollec t ions in t he perirenal and pararenal spac es, int erf asc ial spac es, and psoas spac e are indic at iv e of injury t o ret roperit oneal organs (253). In injuries t o hollow organs, suc h as t he int est ine, CT f indings inc lude bow el w all or muc osal f old t hic kening, f ree int ra- or ret roperit oneal gas, perit oneal f luid, and small bow el obst ruc t ion result ing f rom an ac ut e hemat oma or a subsequent st ric t ure (267). Lap- belt ec c hy mosis oc c urs in approximat ely 70% of c hildren w it h bow el injuries and is a c linic al c lue t o t he diagnosis (257). F indings assoc iat ed w it h rupt ure of t he urinary bladder inc lude t hic kening of t he bladder w all and leakage of c ont rast - enhanc ed urine int o t he perit oneal or ext raperit oneal spac es (252). Hy poperf usion assoc iat ed w it h hy pov olemic shoc k has a c harac t erist ic CT appearanc e, ev idenc ed by dif f usely dilat ed, f luid- f illed small bow el loops; int ense c ont rast - enhanc ement of t he kidney s, bow el w all, and mesent ery ; a f lat t ened or c ollapsed IVC and a small aort a; and int raperit oneal f luid (256) (see F ig. 24- 73). It is c rit ic al t hat t he radiologist rec ognize t he CT f indings of hy poperf usion, as t hey are indic at iv e of a sev ere injury and a poorer prognosis.

Diffuse Liver Diseases Diagnoses of dif f use diseases of t he liv er c an be made w it h eit her CT or MRI (179). Cirrhosis is t he result of dif f use, irrev ersible hepat oc y t e damage and replac ement by f ibrosis, usually as a c onsequenc e of c hronic hepat it is, bile st asis, met abolic disorders, c ongenit al hepat ic f ibrosis, or t oxins. Charac t erist ic f indings inc lude a small right hepat ic lobe and medial segment of t he lef t lobe, enlargement of t he c audat e lobe and lat eral segment of t he lef t lobe, het erogeneous parenc hy ma, and nodular hepat ic margins. T he regenerat ing nodules of c irrhosis may be mac ronodular or mic ronodular. Regenerat ing nodules are of t en isodense t o liv er on CT and isoint ense on MRI. Some nodules may show iron deposit ion. Siderot ic nodules c an show a high at t enuat ion on CT , high signal int ensit y on T 1- w eight ed MR images, and low signal int ensit y on T 2- w eight ed images (F ig. 24- 75). Ext rahepat ic f indings, indic at iv e of port al hy pert ension, inc lude splenomegaly , asc it es, and dilat ed c ollat eral v essels in t he port a hepat is and umbilic al and splenic regions.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3638

24 - Pediatric Applications

F igure 24- 75 Cirrhosis in a 3- y ear- old girl w it h t y rosinemia. T 1- w eight ed magnet ic resonanc e image show s a het erogeneous liv er w it h irregular margins and mult iple high- signal- int ensit y lesions in bot h hepat ic lobes, represent ing siderot ic nodules.

At t enuat ion v alues higher t han normal c an oc c ur w it h hepat ic iron ov erload, usually assoc iat ed w it h repeat ed blood t ransf usions and oc c asionally w it h gly c ogen st orage disease (72,176). As a result of t he inc reased CT densit y , t he hepat ic v essels appear as low - densit y branc hing st ruc t ures against t he bac kground of t he hy perdense liv er on unenhanc ed sc ans. Alt hough CT c an be used t o ev aluat e iron ov erload, MRI is more sensit iv e f or t he diagnosis. On MRI, t he paramagnet ic ef f ec t of t he f erric ions in t he st ored iron leads t o a low signal int ensit y on bot h T 1- and T 2- w eight ed images. F at t y c hange, of t en assoc iat ed w it h f ulminant liv er diseases, sev ere malnut rit ion, c y st ic f ibrosis, and c hemot herapy , is c learly rec ognized on CT as diminished hepat ic densit y (176) (F ig. 24- 76A). T he dec rease in hepat ic at t enuat ion may be f oc al or dif f use and direc t ly c orresponds t o t he amount of f at deposit ed in t he liv er. Wit h dif f use f at t y c hange, t he port al v eins appear as high- densit y st ruc t ures against t he bac kground of t he low er densit y hepat ic parenc hy ma. MR w it h in- and opposed- phase imaging c an be used t o c orroborat e CT f indings (F ig. 24- 76B). Ult rasonography (US) is t he proc edure of c hoic e t o sc reen f or dif f use inf ilt rat iv e diseases of t he liv er. T he role of CT and MRI is t o c larif y equiv oc al sonographic f indings. CT and MRI also are rec ommended t o prov ide addit ional inf ormat ion about v asc ular anat omy in pat ient s w ho are sc heduled t o undergo liv er t ransplant at ion. Af t er liv er

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3639

24 - Pediatric Applications P.1766 t ransplant at ion, US, CT , or MRI c an be used t o ev aluat e biliary or v asc ular c omplic at ions.

F igure 24- 76 F oc al f at t y liv er in an adolesc ent boy w it h Crohn disease. A: Comput ed t omography show s mult iple low - at t enuat ion areas in t he liv er. B: On t he opposed- phase magnet ic resonanc e image, t hese areas hav e low signal int ensit y , indic at ing t he presenc e of f at .

Biliary Tract Obstruction Biliary t rac t obst ruc t ion in c hildren usually is t he result of duc t al c alc uli or ac ut e panc reat it is. A rare c ause of duc t al obst ruc t ion is rhabdomy osarc oma. T he CT diagnosis is based on demonst rat ion of dilat ed int ra- or ext rahepat ic bile duc t s of near- w at er at t enuat ion. Assoc iat ed f indings inc lude duc t al c alc if ic at ions, panc reat ic enlargement , or a sof t t issue mass in t he port a hepat is (200,211). In jaundic ed pat ient s, US is t he preliminary imaging proc edure t o det ec t int rahepat ic duc t al dilat at ion assoc iat ed w it h obst ruc t ion, as w ell as c y st ic diseases. Sonography c an be supplement ed w it h radionuc lide st udies using hepat obiliary imaging agent s. Alt hough t he abilit y of CT t o doc ument t he presenc e of dilat ed bile duc t s is w ell know n, CT should be reserv ed f or c ases in w hic h t he lev el or c ause of obst ruc t ion c annot be det ermined by t hese ot her radiologic met hods (80). MRI c an also det ec t biliary dilat at ion, but it of f ers no addit ional inf ormat ion ov er t hat prov ided by US or CT .

Renal Parenchymal Disease

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3640

24 - Pediatric Applications Most renal c alc if ic at ions in c hildren are assoc iat ed w it h obst ruc t ion and inf ec t ion, and less f requent ly are a result of met abolic disorders, c ort ic al nec rosis, glomerulonephrit is, or adrenoc ort ic ot ropic hormone (ACT H) t herapy . CT may be of v alue in c onf irming lit hiasis or nephroc alc inosis suspec t ed on c linic al ev aluat ion or sonography (120). Ac ut e py elonephrit is c an present as unif orm enlargement of t he kidney . Non–c ont rast - enhanc ed CT images usually are normal, w hereas c ont rast enhanc ed images may show single or mult iple low - densit y areas, presumably relat ed t o inf lammat ory hy pov asc ularit y , v asoc onst ric t ion, or mic roabsc esses (120,226,243) (F ig. 24- 77). In some c ases, a st riat ed pat t ern, c harac t erized by bands of alt ernat ing inc reased and dec reased densit y , c an be observ ed. T his is believ ed t o represent c apillary st asis or hy perdense urine w it hin t ubules plugged by inf lammat ory debris. Assoc iat ed f indings inc lude c alic eal dist ort ion and perinephric inf lammat ion, manif est ed by t hic kening of Gerot a's f asc ia and st rands of inc reased densit y in t he perinephric f at . More sev ere

inf ec t ion c an produc e a renal absc ess. T he CT appearanc e of renal absc ess is t hat of a spheric al, low - densit y mass w it h t hic k, irregular w alls. A CT diagnosis of c hronic py elonephrit is is based on rec ognit ion of a small kidney w it h c ort ic al sc ars ov erly ing c lubbed c aly c es. Unilat eral renal hy poplasia or renal art ery st enosis, P.1767 in c ont radist inc t ion, is assoc iat ed w it h a small, smoot h kidney . MRI does not of f er addit ional inf ormat ion ov er t hat prov ided by CT .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3641

24 - Pediatric Applications F igure 24- 77 Ac ut e bac t erial py elonephrit is, 4- y ear- old girl. Cont rast enhanc ed c omput ed t omography show s an enlarged right kidney w it h sev eral

poorly enhanc ing areas, represent ing more sev ere areas of bac t erial nephrit is. Urine c ult ures grew Esc her ic hia c oli.

F igure 24- 78 Renal v ein t hrombosis in a 4- y ear- old boy w it h lef t f lank pain. Cont rast - enhanc ed c omput ed t omography during t he exc ret ory phase show s an enlarged lef t kidney w it h poor exc ret ion. T hrombus is not ed in t he lef t renal v ein (ar r ow s).

A v oiding c y st ouret hrogram (VCUG) and a sonogram are t he init ial imaging examinat ions in a c hild w it h an init ial urinary t rac t inf ec t ion. T he VCUG is used t o inv est igat e t he possibilit y of ref lux. CT may be a v aluable anc illary examinat ion in pat ient s w it h ac ut e py elonephrit is suspec t ed of hav ing perinephric ext ension or a c omplic at ing absc ess, bec ause it prov ides a bet t er t opographic display of t he kidney and it s adjac ent st ruc t ures t han does sonography .

Renal Vascular Diseases Sonography is c onsidered t he imaging t est of c hoic e f or diagnosis of renov asc ular disease, but in equiv oc al c ases CT or MRI c an c onf irm t he diagnosis. Renal v ein t hrombosis in c hildren oc c urs as a result of t rauma, neoplast ic inv asion of t he renal v ein, or dehy drat ion. CT and MRI f indings of ac ut e t hrombosis inc lude unilat eral renal enlargement , a prolonged c ort ic omedullary phase of enhanc ement , diminished c ont rast exc ret ion int o t he c ollec t ing sy st em, t hrombus in t he renal v ein or IVC, and t hic kening of Gerot a's f asc ia (F ig. 24- 78).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3642

24 - Pediatric Applications Ac ut e renal inf arc t ion in c hildren is most of t en a global ev ent and a c omplic at ion of t raumat ic or neoplast ic oc c lusion of t he renal art ery . CT and MRI f indings inc lude a normal- size kidney and absent parenc hy mal enhanc ement . Peripheral rim enhanc ement may be seen as a result of

perf usion by c apsular v essels (185) (F ig. 24- 79). T he oc c lusion usually oc c urs w it hin t he proximal 2 c m of t he renal art ery . Segment al inf arc t ion is less c ommon and may result f rom a v asc ulit is or embolus f rom an indw elling art erial line. Segment al inf arc t ion appears as a sharply demarc at ed, of t en w edgeshaped area t hat has a low densit y on c ont rast - enhanc ed CT , low signal int ensit y on T 1- w eight ed and gadolinium- enhanc ed images, and high signal int ensit y on T 2- w eight ed images.

F igure 24- 79 Renal art ery oc c lusion. Comput ed t omography show s an absent lef t nephrogram w it h an enhanc ing c ort ic al rim (ar r ow s).

Pancreatic Disorders Hereditary Diseases Heredit ary panc reat ic diseases inc lude c y st ic f ibrosis (CF ) and Shw ac hmanDiamond sy ndrome, w hic h are aut osomal rec essiv e disorders, and v on HippelLindau disease and heredit ary panc reat it is, w hic h are aut osomal dominant diseases (92,143). Inv olv ement of t he panc reas in CF t akes t he f orm of a f at t y panc reas, parenc hy mal c alc if ic at ions, or single or mult iple large c y st s, ref erred t o as panc reat ic c y st osis (92,262) (F ig. 24- 80). Shw ac hmanP.1768

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3643

24 - Pediatric Applications Diamond sy ndrome (exoc rine panc reat ic insuf f ic ienc y , neut ropenia, met aphy seal dy sost osis, and dw arf ism) also is c harac t erized by f at t y

replac ement of t he panc reas, c ausing a low at t enuat ion v alue on CT and high signal int ensit y on MRI (92). In Von Hippel- Lindau disease, t he panc reas c ont ains mult iple c y st s. F indings in pat ient s w it h heredit ary panc reat it is inc lude duc t al dilat at ion, parenc hy mal and duc t al c alc if ic at ions, and panc reat ic at rophy (92).

F igure 24- 80 Cy st ic f ibrosis, 15- y ear- old boy . T he panc reas (P) is c omplet ely replac ed by f at t y t issue. T he liv er has diminished densit y , also sec ondary t o f at t y replac ement .

F igure 24- 81 Ac ut e panc reat it is in a 7- y ear- old boy . A: Comput ed t omography (CT ) image at t he lev el of t he panc reat ic body and t ail show s f luid in t he lesser sac (w hit e ar r ow ) and in t he subhepat ic spac e (blac k ar r ow s). T he panc reas (P) is minimally enlarged. B: CT image at a more c audal

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3644

24 - Pediatric Applications

lev el demonst rat es f luid in t he parac olic gut t ers and edema in t he small bow el mesent ery .

Pancreatitis Ac ut e panc reat it is in c hildhood is most of t en a result of blunt abdominal t rauma, but ot her c auses inc lude operat iv e t rauma, c hemot herapy , CF , mumps, and c ongenit al anomalies, suc h as panc reas div isum and duplic at ion c y st . T he CT c hanges of panc reat it is inc lude dif f use glandular enlargement , c ont our irregularit y , and int rapanc reat ic or ext rapanc reat ic f luid c ollec t ions (126). Ext rapanc reat ic f luid in c hildren is seen most of t en in t he ant erior pararenal spac e, f ollow ed by t he lesser sac , lesser oment um, and t ransv erse mesoc olon (126) (F ig. 24- 81). T he f luid c ollec t ions in ac ut e panc reat it is are of w at er densit y and v ariable in size and shape, dist ending an already exist ing spac e in t he ret roperit oneal or int raperit oneal c ompart ment . T hey are not c onsidered pseudoc y st s. Pseudoc y st s hav e a t hic k f ibrous c apsule, are usually f ound in c lose proximit y t o t he panc reas, and c ont ain homogeneous f luid of near- w at er at t enuat ion v alue. T hey are more permanent in nat ure and unlikely t o resolv e spont aneously (218). Chronic panc reat it is in c hildhood usually is a result of heredit ary panc reat it is, and less f requent ly a result of malnut rit ion, hy perparat hy roidism, CF , idiopat hic f ibrosing panc reat it is, or panc reas div isum. CT manif est at ions of c hronic panc reat it is inc lude c alc if ic at ions, f oc al or dif f use panc reat ic enlargement or at rophy , panc reat ic or biliary duc t al dilat at ion, inc reased densit y of t he peripanc reat ic f at , and t hic kening of t he peripanc reat ic f asc ia. In pat ient s w it h good c linic al ev idenc e support ing t he diagnosis of unc omplic at ed ac ut e panc reat it is, neit her US or CT is nec essary . Diagnost ic ev aluat ion is reserv ed f or pat ient s suspec t ed of hav ing c omplic at ions. US is pref erred as t he sc reening examinat ion bec ause it does not require ionizing radiat ion. In c ases in w hic h US is subopt imal bec ause of bow el gas, c ommonly present in pat ient s w it h ac ut e panc reat it is, CT may be used t o prov ide t he needed inf ormat ion. CT is c onsidered t he proc edure of c hoic e f or display ing c alc if ic at ion in pat ient s suspec t ed of hav ing heredit ary panc reat it is. MRI does not c ont ribut e usef ul inf ormat ion in panc reat it is ov er t hat prov ided by CT .

Bowel Diseases

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3645

24 - Pediatric Applications Sev eral c ongenit al and ac quired anomalies c an af f ec t t he bow el in c hildhood, but only t he more c ommon ones ev aluat ed by CT or MRI are disc ussed here.

Congenital Anomalies Anorec t al malf ormat ions are c harac t erized by v ary ing degrees of at resia of t he dist al hindgut and t he lev at or sling. Preoperat iv e CT and MRI c an prov ide inf ormat ion about t he lev el of at resia and t he t hic kness of t he puborec t alis musc le and ext ernal anal sphinc t er. Post operat iv ely , t hey c an show t he posit ion of t he neorec t um in t he lev at or ani sling (276) (F ig. 24- 82). T he neorec t um needs t o be posit ioned w it hin bot h t he puborec t alis and ext ernal sphinc t er musc les if rec t al c ont inenc e is t o be ac hiev ed. An addit ional c ongenit al anomaly t hat c an be diagnosed by CT or MRI is malrot at ion. CT and MRI f indings inc lude inv ersion of t he superior mesent eric v essels, w it h t he art ery ly ing ant erior or t o t he right of t he v ein; posit ioning of t he jejunum on t he right and t he c olon on t he lef t ; and a w hirl- like appearanc e of t he small bow el mesent ery (F ig. 24- 83) (288).

F igure 24- 82 Congenit al anorec t al anomaly . A 10- y ear- old boy w it h rec t al inc ont inenc e af t er a pull- t hrough operat ion f or t reat ment of an imperf orat e anus. T ransaxial T 2- w eight ed magnet ic resonanc e image show s t he neorec t um (R) ly ing w it hin a hy poplast ic puborec t alis sling (ar r ow s) loc at ed in t he midline.

P.1769

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3646

24 - Pediatric Applications Inflammation Crohn disease is t he most f requent inf lammat ory c ondit ion af f ec t ing t he small bow el in c hildren. CT has been show n t o be usef ul t o diagnose ext raluminal ext ension or absc ess (106,229). CT f indings in t he early st age of Crohn disease inc lude c irc umf erent ial bow el w all t hic kening, inf lammat ion of t he adjac ent mesent eric f at , and enlarged regional ly mph nodes (106,229) (F ig. 24- 84). Inc reased amount s of mesent eric f at , segment al narrow ed areas of bow el, and f ist ulas, sinus t rac t s, or absc esses may be seen in adv anc ed disease. Ot her inf lammat ory small bow el c ondit ions t hat c an be imaged by CT inc lude Y ersinia ileit is, t uberc ulosis, and hist oplasmosis. T he CT appearanc es of t hese diseases are similar t o t hose of Crohn disease.

F igure 24- 83 Malrot at ion. Cont rast - enhanc ed c omput ed t omography show s rev ersal of t he normal orient at ion of t he superior mesent eric v essels, w it h t he art ery (blac k ar r ow ) ly ing t o t he right of t he v ein (w hit e ar r ow ).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3647

24 - Pediatric Applications F igure 24- 84 Crohn disease. A 14- y ear- old boy w it h a palpable right low er

quadrant mass. Comput ed t omography show s c irc umf erent ial t hic kening of t he w all of t he dist al ileum (ar r ow s) and an inc reased amount of mesent eric f at in t he right low er quadrant .

Inf lammat ory diseases of t he c olon and appendix also c an be easily diagnosed by CT . In pat ient s w it h ulc erat iv e c olit is, t here is c onc ent ric c olonic w all t hic kening, w hic h usually is het erogeneous. T he CT f indings in granulomat ous c olit is are similar t o t hose seen in t he small bow el, exc ept t hat t he c olonic w all t ends t o be t hic ker (106,229). Ac ut e appendic it is is manif est ed as a dilat ed appendix, measuring bet w een 8 and 12 mm in diamet er, w it h a t hic k enhanc ing w all (F ig. 24- 85) (68,115,178,258). By c omparison, in c hildren w it hout appendic it is, appendic eal diamet er ranges bet w een 3 and 8 mm and t he appendic eal w all is barely perc ept ible. Ot her f indings of appendic it is inc lude an appendic olit h (see F ig. 24- 85) and peric ec al P.1770 inf lammat ion, appearing as st reaky opac it ies in t he adjac ent f at . An absc ess, as expec t ed, appears as a w alled- of f f luid c ollec t ion w it h an enhanc ing w all (see F ig. 24- 72).

F igure 24- 85 Ac ut e appendic it is, 7- y ear- old girl. Comput ed t omography demonst rat es a dilat ed, f luid- f illed appendix (ar r ow s) w it h an enhanc ing w all and an appendic olit h (ar r ow head).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3648

24 - Pediatric Applications

F igure 24- 86 Int ussusc ept ion. Comput ed t omography of a 9- y ear- old girl w it h abdominal pain. T he bow el has a t arget - like appearanc e (ar r ow s) w it h a c ent ral sof t t issue densit y a surrounding lay er of mesent eric f at , and an out er lay er of c ont rast and sof t t issue.

Noninf lammat ory bow el diseases, suc h as Henoc h- Sc hönlein purpura and graf t - v ersus- host disease (GVHD), are also easily rec ognized by CT . In pat ient s w it h Henoc h- Sc hönlein purpura, a nont hromboc y t openic v asc ulit is, t here is small bow el w all t hic kening, w hic h usually has a high at t enuat ion bec ause of int ramural bleeding (112). T he CT f indings of GVHD, w hic h is a c omplic at ion of het erot opic bone marrow t ransplant at ion, are dilat ed f luidf illed loops of large and small bow el w it h t hic kened w alls and enhanc ing muc osa (58,59). Ext raint est inal f indings inc lude ring- like muc osal enhanc ement of t he gallbladder and urinary bladder w all, inf lammat ion of t he mesent eric f at , inc reased mesent eric v asc ularit y , and asc it es.

Obstruction T he most f requent lesions produc ing obst ruc t ion are adhesions, hernias, and int ussusc ept ion. In obst ruc t ion, bow el loops proximal t o an obst ruc t ing lesion are dilat ed and f illed w it h f luid or c ont rast , c ompared t o loops dist al t o t he sit e of obst ruc t ion. T he CT diagnosis of hernia is based on t he demonst rat ion of bow el or a c ombinat ion of bow el, mesent eric f at , and v essels w it hin a hernia sac . T he CT appearanc e of int ussusc ept ion is t hat of a t arget sign, w it h a c ollapsed segment of proximal bow el (t he int ussusc ept um) and it s

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3649

24 - Pediatric Applications

surrounding lay er of f at - c ont aining mesent ery ly ing w it hin a segment of dist al bow el (t he int ussusc ipiens) (45) (F ig. 24- 86). Regardless of t he c ause, t he bow el loops dist al t o t he sit e of obst ruc t ion are c ollapsed, w hereas t hose more proximal are dilat ed and f illed w it h f luid, gas, or c ont rast medium.

Vascular Lesions Aneury sms are rare in c hildren and oc c ur most f requent ly in assoc iat ion w it h Marf an sy ndrome, c ollagen v asc ular diseases, sepsis, or t rauma. T hrombosis also is unc ommon and usually is t he result of sev ere illness assoc iat ed w it h int ense dehy drat ion, t umor ext ension, or t rauma. In addit ion, v arious dev elopment al anomalies of t he v enous sy st em c an oc c ur, and t heir rec ognit ion is import ant lest t hey be misint erpret ed as pat hology . CT or MRI c an be used t o diagnose c ongenit al anomalies or ac quired lesions of t he abdominal v asc ular st ruc t ures (14,268). US is t he pref erred examinat ion f or c onf irming a suspec t ed aneury sm or v enous t hrombosis, bec ause it c an easily demonst rat e t he dimensions and t he ef f ec t iv e lumina of t he aort a or v ena c av a and t heir branc hes in longit udinal and t ransv erse sec t ions. How ev er, if t he abdomen is obsc ured by bow el gas, CT or MRI c an prov ide t he nec essary inf ormat ion.

PELVIS T he major indic at ions f or CT and MRI examinat ion of t he pediat ric pelv is are t he ev aluat ion of a suspec t ed or know n pelv ic mass and t he det erminat ion of t he presenc e or absenc e of a suspec t ed absc ess. In addit ion t o f ac ilit at ing ev aluat ion of pat ient s suspec t ed of hav ing masses or absc esses, CT and MRI c an be usef ul in c harac t erizing c ongenit al ut erine malf ormat ions, loc alizing nonpalpable t est es, and ev aluat ing t he response of malignant t umors t o t herapy (23,236,244,264).

Pelvic Masses Ovarian Masses Nonneoplast ic f unc t ional c y st s, result ing f rom exaggerat ed dev elopment of f ollic ular or c orpus lut eum c y st s, are t he most c ommon ov arian masses in inf ant and adolesc ent girls. An ov arian c y st appears as a large (great er t han 3 c m), uniloc ular, t hin- w alled mass t hat has near- w at er densit y c ont ent s. On

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3650

24 - Pediatric Applications MRI, t he c y st has v ery low signal int ensit y on T 1- w eight ed images and an ext remely high signal int ensit y on T 2- w eight ed images (23,236,244,264).

Int rac y st ic bleeding c an inc rease t he CT at t enuat ion or t he signal int ensit y on T 1- w eight ed images. In some c ases, lay ering of f luid and high signal int ensit y blood c an be observ ed. Mat ure t erat omas or dermoid c y st s are t he most c ommon pediat ric ov arian neoplasms. Pat ient s usually present bet w een 6 and 11 y ears of age w it h a palpable mass or w it h pain result ing f rom t orsion or hemorrhage. T he CT diagnosis of t erat oma is based on ident if ic at ion of a c y st ic P.1771 mass c ont aining f at or a c ombinat ion of f at t y t issue, c alc if ic at ion, ossif ic at ion, or t eet h (108,194,236,245) (F ig. 24- 87). MRI f indings v ary depending on t he t issue c omposit ion. On T 1- w eight ed images, f at appears as an area of high signal int ensit y , w hereas serous f luid and c alc if ic at ions hav e low signal int ensit y . On T 2- w eight ed images, f at and serous f luid show high signal int ensit y , w hereas c alc if ic at ions, bone, and hair demonst rat e low signal int ensit y (287).

F igure 24- 87 Benign ov arian t erat oma, 13- y ear- old girl. Cont rast - enhanc ed c omput ed t omography show s a low - densit y t erat oma, w it h an at t enuat ion v alue c lose t o t hat of w at er, ly ing ant erior t o t he spine. T he t erat oma c ont ains a mural nodule w it h c alc if ic at ion and f at (ar r ow ).

Malignant ov arian neoplasms are most c ommonly (60% t o 90%) germ c ell t umors (dy sgerminoma, immat ure t erat oma, endodermal sinus t umor, embry onal c arc inoma, and c horioc arc inoma) and less c ommonly st romal t umors (Sert oli-

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3651

24 - Pediatric Applications Ley dig, granulosa t hec a) or epit helial c arc inomas (33). On CT , malignant t umors are large (av erage diamet er 15 c m), het erogeneous, sof t t issue masses, c ont aining low - at t enuat ion areas of nec rosis, c alc if ic at ions, t hic k sept at ions, or papillary projec t ions (27,194,244) (F ig. 24- 88). Cul- de- sac f luid, asc it es, perit oneal implant s, ly mphadenopat hy , and hepat ic met ast ases also may be not ed. On MRI, malignant ov arian neoplasms appear as het erogeneous masses w it h int ermediat e signal int ensit y on T 1- w eight ed images and int ermediat e or high signal int ensit y on T 2- w eight ed images (27,194,236). Ot her c auses of an adnexal mass inc lude ov arian t orsion and t ubo- ov arian absc ess. T he f eat ures of ov arian t orsion are an enlarged ov ary of sof t t issue densit y on CT (74,244). T he ov ary has a low signal int ensit y on T 1- w eight ed

MR images and v ery high signal int ensit y on T 2- w eight ed MR images, ref lec t ing v asc ular engorgement and edema (236). Absc esses hav e an appearanc e similar t o t hat of absc esses in ot her part s of t he body .

Vaginal/Uterine Masses Hy droc olpos or hy dromet roc olpos is t he most c ommon c ause of v aginal or ut erine enlargement . Hy droc olpos ref ers t o dilat at ion of t he v agina, usually by serous f luid or somet imes P.1772 urine if t here is a urogenit al sinus; hy dromet roc olpos ref ers t o dilat at ion of bot h t he ut erus and t he v agina. Bot h c ondit ions are c aused by v aginal obst ruc t ion, result ing f rom v aginal at resia or st enosis or an imperf orat e membrane. T he c linic al f eat ures v ary w it h pat ient age. Af f ec t ed neonat es present w it h a pelv ic or low er abdominal mass or assoc iat ed anomalies, inc luding imperf orat e anus, esophageal or duodenal at resia, and c ongenit al heart disease. Adolesc ent girls present w it h a pelv ic mass or pain. T he dilat ed v agina in t his age group of t en c ont ains blood (i.e., hemat oc olpos) as a result of phy siologic hormonal st imulat ion.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3652

24 - Pediatric Applications

F igure 24- 88 Malignant ov arian t umors. A: Malignant t erat oma, 11- y ear- old girl. Comput ed t omography (CT ) show s a large, predominant ly sof t t issue mass c ont aining f oc i of c alc if ic at ion and f at t hat f ills t he low er abdomen. B: Dy sgerminoma, 11- y ear- old girl. Cont rast - enhanc ed CT show s a solid het erogeneously enhanc ing sof t t issue t umor f illing t he pelv is and displac ing bow el superiorly and t o t he lef t . T he predominanc e of sof t t issue element s in bot h t umors should suggest t hat t hese lesions are malignant rat her t han benign.

F igure 24- 89 Hy droc olpos as a result of v aginal membranes in t w o adolesc ent girls w it h pelv ic pain. A: Comput ed t omography sc an show s a dilat ed, f luidf illed v agina (V). B: Sagit t al T 1- w eight ed magnet ic resonanc e image show s an enlarged, int ermediat e signal int ensit y v agina (V). T he f luid in bot h pat ient s represent ed blood produc t s.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3653

24 - Pediatric Applications On CT , t he dilat ed v agina and ut erus appear as midline, near- w at er densit y masses. T he w alls may enhanc e af t er administ rat ion of int rav enous c ont rast medium (F ig. 24- 89A) (244,264). On MRI, t hey hav e low signal int ensit y on T 1- w eight ed images (F ig. 24- 89B) and high signal int ensit y on T 2- w eight ed

images. T he signal int ensit y is high on T 1- w eight ed images if t he c ont ent s are hemorrhagic (236,245). Int ra- abdominal ext ension and hy dronephrosis result ing f rom uret eral c ompression c an be seen in long- st anding obst ruc t ion. Rhabdomy osarc oma is t he most c ommon malignant ut erine and v aginal t umor in c hildhood. On CT , rhabdomy osarc oma appears as a sof t t issue mass w it h an at t enuat ion v alue approximat ing t hat of musc le. Nec rosis or c alc if ic at ion also c an be present , along w it h v ariable enhanc ement af t er int rav enous administ rat ion of c ont rast mat erial. Met ast ases t o pelv ic ly mph nodes c an be seen if t he inv olv ed nodes are enlarged. Rhabdomy osarc oma usually has low signal int ensit y on T 1- w eight ed MR images and high signal int ensit y on T 2w eight ed MR images (8,64,220).

Bladder and Prostate Masses Rhabdomy osarc oma ac c ount s f or most neoplasms of t he bladder and prost at e in c hildren. It t y pic ally af f ec t s c hildren under 10 y ears of age and usually met ast asizes early , eit her by a ly mphat ic rout e t o regional ly mph nodes or by a hemat ogenous rout e t o lung, bone, and liv er. T he CT and MRI f eat ures are similar t o t hose of v aginal rhabdomy osarc oma (8,64,220) (F ig. 24- 90). Less c ommon bladder neoplasms inc lude hemangioma, neurof ibroma, pheoc hromoc y t oma, leiomy oma, and t ransit ional c ell c arc inoma. On CT and MRI, t hese appear as pedunc ulat ed or sessile sof t t issue masses projec t ing int o t he bladder lumen. Based on CT or MRI f indings alone, it is usually impossible t o dif f erent iat e a benign lesion f rom a malignant one. How ev er, w hen t here is ext ension int o t he periv esic al f at or adjac ent st ruc t ures, malignanc y should be suspec t ed.

Presacral Masses Sac roc oc c y geal t erat oma, neuroblast oma, ant erior meningoc ele, and ly mphoma are t he most f requent presac ral masses. Sac roc oc c y geal t erat omas are c ongenit al t umors c ont aining deriv at iv es of all t hree germinal lay ers. Most t erat omas are benign in pat ient s under 2 mont hs of age, but in c hildren bey ond t he neonat al period, t hey hav e a higher f requenc y of malignanc y , nearing 90%. Af f ec t ed c hildren usually present w it h a large sof t t issue mass in

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3654

24 - Pediatric Applications

t he sac roc oc c y geal or glut eal region and less of t en w it h c onst ipat ion or pelv ic pain. On CT , t he diagnosis of sac roc oc c y geal t erat oma c an be c onf irmed by ident if ic at ion of a c y st ic mass c ont aining f at , c alc if ic at ion, bone, or t eet h. Usually t here are no assoc iat ed osseous anomalies (122,220). P.1773 In general, predominant ly f luid- f illed t erat omas are benign (F ig. 24- 91), w hereas t umors c ont aining predominant ly solid c omponent s are more likely t o be malignant (F ig. 24- 92) (194). F luid- f illed, c y st ic sac roc oc c y geal t erat omas hav e a low signal int ensit y on T 1- w eight ed MR images and a high signal int ensit y on T 2- w eight ed MR images. F at appears as high signal int ensit y f oc i on T 1- w eight ed images, and c alc if ic at ion, bone, or hair appears as f oc i of low signal int ensit y on bot h T 1- and T 2- w eight ed images (F ig. 24- 93) (122,220).

F igure 24- 90 Prost at ic rhabdomy osarc oma. A: Cont rast - enhanc ed c omput ed t omography at t he lev el of t he pubic sy mphy sis in a 3- y ear- old boy w it h urinary ret ent ion show s a large, het erogeneous sof t t issue mass (M) in t he expec t ed loc at ion of t he prost at e gland. B: Axial T 2- w eight ed magnet ic resonanc e image in a 2- y ear- old boy demonst rat es a large het erogeneous sof t t issue t umor (T ) post erior t o t he bladder (B).

Ant erior meningoc eles are herniat ions of spinal c ont ent s t hrough a c ongenit al def ec t in t he v ert ebral body (ant erior dy sraphism) and are most c ommon in t he sac ral region and at t he lumbosac ral junc t ion. T he mass is t ermed a my elomeningoc ele in c ases in w hic h t he c ont ent s of t he herniat ed sac c ont ain neural element s in addit ion t o meninges and c erebrospinal f luid, and is t ermed a lipomeningoc ele in c ases in w hic h f at and c erebrospinal f luid are present .

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3655

24 - Pediatric Applications Meningoc eles or my elomeningoc eles are rec ognized on CT by t heir relat iv ely low at t enuat ion v alues P.1774 (c erebrospinal f luid or f at ), t heir posit ion ant erior t o t he sac rum, and t he assoc iat ed sac ral def ec t s. T he sof t t issue c ont ent s of t he herniat ed sac , espec ially t he presenc e of a t et hered c ord, and t he c ommunic at ion bet w een t he meningoc ele and t he t hec al sac c an be demonst rat ed best w it h MRI. Neuroblast oma and ly mphoma arise less f requent ly in t he pelv is t han in t he abdomen or c hest . On CT , bot h appear as presac ral sof t t issue masses. Neuroblast omas and ly mphomas hav e a signal int ensit y slight ly higher t han t hat of st riat ed musc le on T 1- w eight ed MR images. On T 2- w eight ed images, t he signal int ensit y is c lose t o t hat of urine or f at (F ig. 24- 94).

F igure 24- 91 Benign sac roc oc c y geal t erat oma in a new born w it h a palpable pelv ic mass. Axial c omput ed t omography show s a c y st ic mass (ar r ow s) w it h sev eral sept at ions in t he presac ral area.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3656

24 - Pediatric Applications

F igure 24- 92 Malignant sac roc oc c y geal t erat oma in an adolesc ent . Cont rast enhanc ed c omput ed t omography sc an show s a predominant ly sof t t issue mass (ar r ow s) w it h a c lust er of c alc if ic at ions in t he presac ral area. T he t umor ext ends int o t he right glut eal area.

F igure 24- 93 Benign sac roc oc c y geal t erat oma in a new born. Sagit t al T 1w eight ed magnet ic resonanc e image show s a presac ral mass (ar r ow s), w it h a predominant signal int ensit y equal t o t hat of f at . T he mass c ont ains sev eral

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3657

24 - Pediatric Applications

low er signal int ensit y nodules, represent ing f luid c omponent s. T he sac rum w as normal.

F igure 24- 94 Presac ral neuroblast oma in a 2- y ear- old. Cont rast - enhanc ed c omput ed t omography show s a sof t t issue t umor (T ) ant erior t o t he sac rum.

F igure 24- 95 Unic ornuat e ut erus w it h a nonc ommunic at ing rudiment ary horn. Axial T 1- w eight ed image show s a single f usif orm ut erine c av it y (ar r ow s), w hic h is dev iat ed t o t he right . T he high signal int ensit y f oc us w it hin t he right endomet rial c av it y represent s blood.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3658

24 - Pediatric Applications Congenital Uterine Malformations Congenit al ut erine malf ormat ions are easily rec ognized and c harac t erized by MRI. CT also c an det ec t and dif f erent iat e c ongenit al anomalies, but it is not perf ormed rout inely bec ause it uses ionizing radiat ion and has subopt imal sof t t issue c ont rast c ompared w it h MRI (63,274).

Uterine Agenesis or Hypoplasia Ut erine malf ormat ions oc c ur in 0.1% t o 0.5% of all w omen. Ut erine agenesis or hy poplasia is best display ed on T 2- w eight ed sagit t al images. In agenesis, t here is no rec ognizable ut erine t issue. In ut erine hy poplasia, t he ut erus is small and exhibit s poorly dif f erent iat ed zonal anat omy and reduc ed endomet rial and my omet rial w idt h (63,274).

Unicornuate Uterus T he c lassic appearanc e of a unic ornuat e ut erus is t he banana shaped ut erus (single f usif orm ut erine c av it y w it h lat eral dev iat ion). In some pat ient s, a rudiment ary c ont ralat eral horn, w hic h may or may not c ommunic at e w it h t he main ut erine body , may be seen (F ig. 24- 95). Renal anomalies oc c ur in about 25% of c ases (63,274).

F igure 24- 96 Ut erus didelphy s. Axial T 2- w eight ed magnet ic resonanc e image demonst rat es duplic at ed ut erine horns (U) w it h a w idened int erc ornual

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3659

24 - Pediatric Applications dist anc e. T w o v aginas and c erv ic es w ere seen on more c audal images. (Case c ourt esy of Shirley Mc Cart hy , MD, New Hav en, CT .)

P.1775

Uterine Duplication T he spec t rum of duplic at ion anomalies inc ludes: ut erus didelphy s (t w o v aginas, t w o c erv ic es, and t w o ut erine c orpora); ut erus bic ornuat e, eit her bic ollis ut erus (single v agina, t w o c erv ic es, and t w o ut eri) or unic ollis ut erus (one v agina, one c erv ix, and t w o ut eri); and ut erus sept us (single ut erus, c erv ix, and v agina w it h a sept um div iding t he ut erus int o t w o c ompart ment s). MRI is part ic ularly v aluable in dif f erent iat ing ut erus didelphy s f rom a bic ornuat e or sept at e ut erus. Hy droc olpos or hy dromet roc olpos assoc iat ed w it h c ongenit al v aginal obst ruc t ion also c an be ev aluat ed (63,274). Ut erus didelphy s and ut erus bic ornuat e hav e a bilobed shape w it h a c onc av e f undal c ont our and my omet rium separat ing t he t w o endomet rial c av it ies (F ig. 24- 96). T he appearanc e of sept at e ut erus is t hat of a single ut erine f undus w it h a c onv ex, f lat or minimally dimpled f undal c ont our and a c ent ral sept um div iding t he endomet rium int o t w o c av it ies (F ig. 24- 97).

Impalpable Testes Ident if ic at ion of an undesc ended t est is or c ry pt orc hidism is import ant bec ause of t he inc reased risk of inf ert ilit y if t he t est is remains undesc ended and bec ause of t he inc reased inc idenc e of malignanc y , part ic ularly w it h an int raabdominal t est is. Early surgery , eit her orc hiopexy in y ounger pat ient s or orc hiec t omy in pat ient s past pubert y , limit but do not eliminat e t hese risks. Preoperat iv e loc alizat ion of a nonpalpable t est is by CT or MRI is helpf ul in expedit ing surgic al management and short ening t he anest hesia t ime. T he CT and MRI diagnosis of an undesc ended t est is is based on det ec t ion of a sof t t issue mass, of t en ov al in shape, in t he expec t ed c ourse of t est ic ular desc ent . T he more normal t he t est is is in size and shape, t he low er is it s at t enuat ion v alue or signal int ensit y on T 1- w eight ed MR images. A v ery at rophic t est is appears as a small f oc us of sof t t issue w it h a densit y or signal int ensit y similar t o t hat of abdominal w all musc ulat ure. T he diagnosis of an undesc ended t est is is easier if t he t est is is in t he inguinal c anal or low er pelv is, w here st ruc t ures usually are sy mmet ric al. Dif f erent iat ion of an

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3660

24 - Pediatric Applications undesc ended t est is f rom adjac ent st ruc t ures, suc h as bow el loops, v essels,

and ly mph nodes, is more of a problem in t he upper pelv is and low er abdomen.

F igure 24- 97 Ut erus sept at e, 18- y ear- old girl. Angled c oronal T 2- w eight ed image show s t w o ut erine horns (U) w it h normal zonal anat omy . A c ont inuous band of my omet rium surrounds t he horns.

US c an det ec t an impalpable undesc ended t est is w hen it is in a high sc rot al or int rac analic ular posit ion, w hic h oc c urs in about 90% of c ases. Bec ause it does not inv olv e ionizing radiat ion, US is rec ommended as t he init ial imaging examinat ion of c hoic e f or loc alizing impalpable t est es. US, how ev er, usually is not reliable f or ident if y ing undesc ended t est es loc at ed higher in t he pelv is or in t he abdomen. T heref ore, if sonographic f indings are equiv oc al or negat iv e and preoperat iv e loc alizat ion of t he t est is is desired, eit her CT or MRI c an be perf ormed, alt hough MRI is pref erred bec ause it does not use ionizing radiat ion.

MUSCULOSKELETAL SYSTEM Skelet al abnormalit ies are nearly alw ay s f irst ident if ied by c onv ent ional radiography . Sc int igraphy is helpf ul t o c onf irm t he presenc e of a skelet al lesion if t he init ial radiograph is nonc onf irmat ory and t o det ermine t he presenc e of met ast at ic disease. CT and MRI are used as c omplement ary st udies t o c onv ent ional radiographs and sc int igraphy P.1776 w hen f urt her def init ion of an abnormalit y is needed (173,241).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3661

24 - Pediatric Applications T he f requent indic at ions f or CT of t he skelet on in c hildren inc lude: (a) c harac t erizat ion of c ongenit al abnormalit ies in areas of c omplex anat omy , (b) assessment of t he ext ent of c omplex f rac t ures and sequelae of skelet al t rauma, and (c ) det erminat ion of t he origin and ext ent of nidus in ost eoid ost eoma. Indic at ions f or MRI are more div erse t han t hose f or CT and inc lude: (a) ev aluat ion of t he ext ent of skelet al and sof t t issue neoplasms, (b)

det erminat ion of t he ext ent of inf ec t ion, (c ) ev aluat ion of sequelae of skelet al t rauma, (d) assessment of int ra- art ic ular derangement , (e) def init ion of anat omy in selec t ed c ongenit al anomalies, (f ) assessment of possible bone inf arc t ion and ost eonec rosis, (g) ev aluat ion of unexplained pain in pat ient s w it h normal c onv ent ional imaging st udies, and (h) assessment of t he response of malignant lesions t o t reat ment .

Bone Marrow T he appearanc e of t he normal bone marrow v aries w it h t he age of t he pat ient (173,222,269,279,281). At birt h, hemat opoiet ic or red marrow predominat es. Short ly t hereaf t er, t here is c onv ersion of red t o y ellow marrow . In t he shaf t s of t he long bones, t his c onv ersion begins in t he diaphy sis and progresses proximally and dist ally t o t he phy seal plat e. By lat e adolesc enc e, t he appendic ular skelet on c ont ains predominant ly y ellow marrow . Epiphy seal c onv ersion oc c urs w it hin a f ew mont hs of t he appearanc e of t he ossif ic at ion c ent er (111). Red marrow has low signal int ensit y on T 1- w eight ed MR images and high signal int ensit y on T 2- w eight ed images, w hereas y ellow marrow appears as high signal int ensit y on bot h T 1- and T 2- w eight ed sequenc es. Inf ilt rat iv e disorders, inc luding t umor, inf ec t ion, and edema alt er marrow c harac t erist ic s on MRI, produc ing low t o int ermediat e signal int ensit y on T 1w eight ed images and high signal int ensit y on T 2- w eight ed images (210,222,232) (F ig. 24- 98). Abnormalit ies are easier t o ident if y in bones w it h predominant ly y ellow marrow . In bones w it h a predominanc e of red marrow , suc h as t hose in inf ant s and y oung c hildren and pat ient s w it h red c ell hy perplasia, dif f erent iat ion bet w een low signal t umor and red marrow c an be dif f ic ult . In t hese indiv iduals, t he use of f at suppression t ec hniques c an enhanc e lesion c onspic uit y . Bec ause t he MRI appearanc e is not spec if ic , a f inal diagnosis depends on c orrelat ion w it h t he pat ient 's hist ory and ot her c linic al inf ormat ion and possibly t issue sampling.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3662

24 - Pediatric Applications Osseous Neoplasms Ninet y perc ent of malignant skelet al t umors are ost eosarc oma or Ew ing sarc oma. Virt ually all malignant bone t umors hav e a nonspec if ic MR appearanc e w it h lesions display ing a low signal int ensit y on T 1- w eight ed MR images, high signal int ensit y great er t han t hat of f at on T 2- w eight ed images (F ig. 24- 99), and v ariable enhanc ement on gadolinium- enhanc ed T 1- w eight ed images depending on t he ext ent of nec rosis (17,65,110,168,173). Low signal int ensit y on T 2- w eight ed images suggest s sc lerosis, part ially ossif ied mat rix, t umor hy poc ellularit y , or large amount s of c ollagen, w hereas marked hy perint ensit y suggest s highly c ellular t umors w it h a high w at er c ont ent or hemorrhage. F luid–f luid lev els result ing f rom lay ering of new and old hemorrhage c an be f ound in t elangiec t at ic ost eosarc omas, alt hough t hey are not spec if ic and also oc c ur in aneury smal bone c y st s, f ibrous dy splasia, and giant c ell t umors.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3663

24 - Pediatric Applications F igure 24- 98 Met ast at ic neuroblast oma, 2- y ear- old boy . Coronal short t au inv ersion rec ov ery image of t he low er ext remit ies show s dif f usely high signal int ensit y marrow , indic at ing w idespread met ast ases.

Plain skelet al radiography remains t he init ial t ec hnique f or t he diagnosis of skelet al t umors. CT and MRI are helpf ul t o f urt her c harac t erize a lesion if plain radiographs are equiv oc al and t o det ermine t he f ull ext ent of a lesion prior t o t reat ment . T he primary role of MRI in ev aluat ing malignant t umors is est ablishing t he ext ent of marrow inv olv ement , sof t t issue and int ra- art ic ular ext ension, and neurov asc ular enc asement f or st aging. Neurov asc ular inv olv ement is best assessed by sequenc es t hat are t ailored t o blood f low , suc h as GRE images. Slow or absent f low , enc asement , and displac ement are f eat ures suggest ing t umor inv olv ement of t he neurov asc ular bundles. MRI and CT are c omparable in det ec t ing ext ensiv e c ort ic al bone dest ruc t ion, but CT is more sensit iv e f or diagnosing subt le c ort ic al erosion. MRI is also used t o ev aluat e t he response t o c hemot herapy and radiat ion t reat ment . In t he ev aluat ion of benign osseous neoplasms of t he skelet on, CT and MRI c an be of v alue in det ermining t he P.1777 ext ent of a lesion or it s spat ial relat ionships f or preoperat iv e planning. Benign osseous lesions usually hav e w ell- def ined margins on CT and MRI examinat ions (F ig. 24- 100). T he at t enuat ion v alue and signal int ensit y of t he mat rix is generally nonspec if ic so t hat c orrelat ion w it h radiographs or t issue sampling is needed f or a f inal diagnosis. Anot her indic at ion f or CT and MRI is det erminat ion of t he prec ise loc at ion of t he nidus in ost eoid ost eomas prior t o surgic al resec t ion (9) (F ig. 24- 101).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3664

24 - Pediatric Applications F igure 24- 99 Ew ing sarc oma, 16- y ear- old boy . A: Coronal T 1- w eight ed magnet ic resonanc e (MR) image show s low - int ensit y t umor in t he right pubic ramus (ar r ow s) w it h an assoc iat ed sof t t issue mass (M). B: Coronal f at sat urat ed T 2- w eight ed MR image show s inc reased signal int ensit y in t he int ramedullary port ion of t he t umor and t he ext ramedullary sof t t issue c omponent of t he t umor. T umor ext ension t hrough t he c ort ex inf eriorly (ar r ow ) is bet t er seen on t he T 2- w eight ed image.

F igure 24- 100 Aneury smal bone c y st . T 2- w eight ed c oronal magnet ic resonanc e image show s a sharply marginat ed lesion (ar r ow s) c ont aining mult iple high signal int ensit y loc ular c omponent s expanding t he dist al right f ibula.

Soft Tissue Neoplasms T he c ommon benign sof t t issue masses in c hildhood are ganglion c y st , lipoma, neurof ibroma, hemat oma, absc ess, and t he v asc ular t umors (e.g., hemangioma, v enous malf ormat ions, and c y st ic hy groma). T he most f requent malignant mass is rhabdomy osarc oma. Sonography is t he init ial examinat ion of c hoic e f or t he st udy of most sof t t issue masses t o det ermine w het her t hey are c y st ic or solid. MRI, how ev er, has bec ome t he examinat ion of c hoic e f or

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3665

24 - Pediatric Applications large lesions t o def ine t he ext ent of t he mass and it s loc al relat ionships (22,235). Small size, w ell- def ined margins w it h a c apsule, P.1778

homogenous mat rix on T 2- w eight ed MR images, and absenc e of edema suggest a benign lesion (22,154,177,235). Poorly def ined margins and a het erogeneous mat rix on T 2- w eight ed images f av or an aggressiv e proc ess (F ig. 24- 102). Bone erosion and inf ilt rat ion of t he neurov asc ular bundles are c onf irmat ory ev idenc e of malignanc y . Unf ort unat ely , some ac ut e hemat omas, absc esses, and benign neoplasms c an hav e an aggressiv e appearanc e, w hereas some malignant neoplasms c an hav e a benign appearanc e.

F igure 24- 101 Ost eoid ost eoma in an 11- y ear- old boy . Axial image show s a ly t ic nidus (ar r ow ) w it h f aint c alc if ic at ion in t he lat eral c ort ex of t he proximal right f emur. T he c ort ex around t he nidus is t hic kened.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3666

24 - Pediatric Applications F igure 24- 102 Rhabdomy osarc oma in a 2- y ear- old girl. A: T 1- w eight ed magnet ic resonanc e image show s an int ermediat e signal int ensit y mass

(ar r ow s) in t he lef t axilla. B: On a f at - sat urat ed T 2- w eight ed image t he mass has high signal int ensit y . T he het erogeneit y is t y pic al of a malignant t umor. Also seen is an enlarged ly mph node (ar r ow ) adjac ent t o t he humeral head (H).

Cert ain sof t t issue lesions hav e spec if ic MR c harac t erist ic s (22,154,177,235). Lipomas appear as w ell- def ined masses w it h a signal int ensit y equal t o t hat of subc ut aneous f at on T 1- and T 2- w eight ed images (134). Ganglion c y st s hav e a signal int ensit y low er t han t hat of skelet al musc le on T 1- w eight ed images and great er t han t hat of f at on T 2- w eight ed and f at - suppressed images. Neurof ibromas appear as w ell- c irc umsc ribed, round or ov oid masses w it h low t o int ermediat e signal int ensit y on T 1- w eight ed images and high signal int ensit y on T 2- w eight ed and gadolinium- enhanc ed images. Most benign neural t umors exhibit a t arget sign, c harac t erized by a low int ensit y c ent er and a hy perint ense rim on T 2- w eight ed images and on c ont rast - enhanc ed T 1w eight ed images (19) (F ig. 24- 103). Hemangiomas are relat iv ely c ommon t umors of t he appendic ular skelet on (131,164). T he blood- f illed spac es of hemangiomas are isoint ense t o musc le on T 1- w eight ed images and hy perint ense on T 2- w eight ed images. T hey enhanc e dif f usely af t er injec t ion of gadolinium c helat e. F oc al het erogeneit ies are present in most c ases, on bot h spin- ec ho and GRE images, relat ed t o hemosiderin deposit s, f ibrosis, f at , c alc if ic at ion, t hrombosis, or st agnant blood (F ig. 24- 104). Assoc iat ed f indings inc lude t he presenc e of f eeding or draining v essels in t he subc ut aneous t issues and musc le at rophy . Ot her v asc ular malf ormat ions inc lude v enous malf ormat ions (c harac t erized by dilat ed v enous spac es and a normal art erial c omponent ) (F ig. 24- 105), art eriov enous P.1779 P.1780 malf ormat ions (c harac t erized by enlarged f eeding art eries and draining v eins w it hout an int erv ening c apillary bed), and ly mphat ic malf ormat ions (c harac t erized by f luid- f illed spac es and f ibrous sept at ions) (F ig. 24- 106).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3667

24 - Pediatric Applications

F igure 24- 103 Plexif orm neurof ibromas. Coronal T 2- w eight ed magnet ic resonanc e image w it h f at sat urat ion demonst rat es t he t y pic al t arget appearanc e of benign neural t umors, w it h a c ent ral zone of low signal int ensit y and a peripheral zone of high signal int ensit y .

F igure 24- 104 Hemangioma, right f orearm. A: Axial T 1- w eight ed image demonst rat es a het erogeneous mass of int ermediat e signal int ensit y replac ing t he post erior musc les. Low signal int ensit y f oc i represent f ibrosis; f oc i of high

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3668

24 - Pediatric Applications signal int ensit y are relat ed t o f at . B: On axial T 2- w eight ed image w it h f at

sat urat ion, t he dilat ed v asc ular c hannels c omprising t he mass hav e high signal int ensit y . Int erspersed t hroughout t he lesion is low signal int ensit y f ibrous t issue. T he inv olv ed musc le is at rophied ev idenc ed by t he absenc e of mass ef f ec t giv en t he large size of t he hemangioma. Dilat ed v essels are also seen in t he subc ut aneous f at . U, ulna; R, radius.

F igure 24- 105 Venous malf ormat ion in a 5- mont h- old boy . Coronal t hreedimensional gradient - ec ho image of t he t high af t er gadolinium c helat e administ rat ion show s enlargement of t he great er saphenous v ein (ar r ow ) and mult iple small high signal int ensit y v enous c hannels.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3669

24 - Pediatric Applications

F igure 24- 106 Cy st ic hy groma, 18- y ear- old girl. Axial T 2- w eight ed image w it h f at sat urat ion demonst rat es mult iple high signal int ensit y c y st s of v ary ing size in t he subc ut aneous t issues of t he lef t upper ext remit y . H, humeral head.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3670

24 - Pediatric Applications F igure 24- 107 Epiphy seal f rac t ure in an 11- y ear- old girl. A: Axial c omput ed t omography image of t he dist al right t ibial epiphy sis show s a linear f rac t ure (ar r ow ). T he relat ionship of t he f rac t ure line t o t he phy sis is dif f ic ult t o apprec iat e on axial sec t ions. B: Coronal mult iplanar image show s ext ension of t he f rac t ure (ar r ow ) t o t he phy sis and w idening of t he phy sis lat erally .

Hemat omas c an be dist inguished f rom hemangiomas on t he basis of signal int ensit y c harac t erist ic s (230). Very ac ut e hemat omas (1 t o 24 hours of age) are generally hy po- or isoint ense t o musc le on T 1- w eight ed images and hy perint ense t o musc le on T 2- w eight ed images. Ac ut e hemat omas (1 t o 7 day s of age) t end t o be hy po- or isoint ense t o musc le on T 1- w eight ed images and hy point ense on T 2- w eight ed images. Subac ut e hemat omas (one w eek t o sev eral mont hs old) are hy perint ense t o f at on T 1- w eight ed images. Chronic hemat omas hav e MR c harac t erist ic s similar t o t hose of ot her f luid c ollec t ions, w hic h inc lude a low signal int ensit y on T 1- w eight ed images and a high signal int ensit y on T 2- w eight ed and f at - suppressed images.

Infection Cross- sec t ional imaging is usef ul in c hildren in w hom c omplic at ions of ost eomy elit is are suspec t ed or drainage is c onsidered. Bot h CT and MRI c an be used t o ev aluat e ost eomy elit is, but MRI is espec ially w ell suit ed f or t he det ec t ion of marrow abnormalit y (e.g., Brodie absc ess and sequest rum) and ext ension int o t he periost eum and sof t t issues (85,133,156). Cort ic al dest ruc t ion and sequest ra are more reliably diagnosed w it h CT (153).

Bone and Joint Trauma T radit ional radiographs remain t he init ial examinat ion of c hoic e in t he ev aluat ion of ac ut e t rauma. When radiographs are not c onf irmat ory , sc int igraphy , CT , or MRI c an be used t o est ablish t he presenc e and ext ent of a f rac t ure (44) (F ig. 24- 107), and in part ic ular, grow t h plat e injuries, w hic h if unrec ognized lead t o grow t h dist urbanc e. CT , w it h 2D or 3D imaging, is espec ially usef ul in t he ev aluat ion of t he axial skelet on and pelv is, w hic h are dif f ic ult t o ev aluat e w it h plain radiographs bec ause of superimposit ion of osseous part s (241). Af t er t he injury has healed, CT or MR imaging c an be used t o def ine t he size and loc at ion of a post t raumat ic bony bridge and t he sev erit y of t he

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3671

24 - Pediatric Applications assoc iat ed grow t h def ormit y (61,144) (F ig. 24- 108). CT is usef ul in t he diagnosis of post t raumat ic ost eoc hondral loose bodies.

MRI is t he examinat ion of c hoic e f or det ec t ing menisc al and ligament ous t ears (109). T ears appear as alt erat ions in morphology and signal int ensit y w it hin t he subst anc e of t he menisc us or ligament . MRI has also been show n t o be an ef f ec t iv e met hod f or ev aluat ing bone marrow edema assoc iat ed w it h ligament ous and c art ilaginous injuries.

Joint Disorders T he most c ommon art hropat hies in c hildhood are juv enile rheumat oid art hrit is (JRA), hemophilia, and pigment ed P.1781 v illonodular sy nov it is (PVNS). MRI is used t o demonst rat e t he ext ent of c art ilaginous and sy nov ial inv olv ement . MRI f indings of early JRA and hemophilia inc lude t hic kened sy nov ium, w hic h has a low signal on T 1- w eight ed images and mixed int ensit y on T 2- w eight ed images, ref lec t ing t he presenc e of inf lammat ion and hemosiderin deposit ion. Lat e c hanges inc lude c art ilage loss and bone erosions. Gadolinium- enhanc ed MRI is superior t o unenhanc ed MRI f or show ing c art ilage loss, joint ef f usion, and sy nov ial t hic kening. PVNS appears as an int ra- art ic ular mass c ont aining areas of dec reased signal int ensit y on all sequenc es, c orresponding t o hemosiderin deposit ion.

F igure 24- 108 Post t raumat ic epiphy seal c losure, 14- y ear- old boy . Comput ed t omography image of t he right w rist obt ained 18 mont hs af t er a Salt er- Harris t y pe IV f rac t ure show s an osseous bridge c rossing t he c ent ral port ion of t he phy seal plat e (ar r ow s).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3672

24 - Pediatric Applications Congenital Anomalies

Dev elopment al hip dy splasia and t arsal c oalit ion are c ongenit al anomalies t hat are w ell suit ed f or CT . Plain radiographs c an diagnose t hese c ondit ions, but CT is usef ul t o show t he prec ise relat ionship bet w een t he bony ac et abulum and t he f emoral head or nec k (101). 3D rec onst ruc t ions are part ic ularly usef ul f or assessing ac et abular c ov erage and def ormit y of t he f emoral head (F ig. 24109). In selec t ed c ases, MR imaging c an be usef ul t o prov ide inf ormat ion about c ov erage of t he c art ilaginous port ion of t he f emoral head.

F igure 24- 109 Dev elopment al dy splasia of t he hip. Comput ed t omography sc an w it h t hree- dimensional rec onst ruc t ion demonst rat es lat eral and superior disloc at ion of t he proximal lef t f emur. T he f emoral head is def ormed, and t here is a shallow pseudoac et abulum (ar r ow ).

T arsal c oalit ion is a c ause of rigid f lat f oot and peroneal spasm in c hildren. Nearly 70% of t arsal c oalit ions are t aloc alc aneal and 30% are c alc aneonav ic ular. F or t aloc alc aneal c oalit ions, sc ans should be obt ained perpendic ular t o t he f oot , w hereas f or c alc aneonav ic ular c oalit ion, sc ans should parallel t he long axis of t he f oot (60,182,282) (F ig. 24- 110). Less f requent indic at ions f or CT inc lude measurement of t he amount of f emoral ant ev ersion or t ibial t orsion (241).

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3673

24 - Pediatric Applications

F igure 24- 110 T arsal c oalit ion. A: Comput ed t omography (CT ) in a 13- y earold boy t hrough t he long axis of t he hind f eet show s bilat eral c alc aneonav ic ular c oalit ions (ar r ow s). B: Short - axis CT image in a 14- y earold boy show s narrow ing and irregularit y of t he c ort ic al surf ac es of t he t aloc alc aneal joint s bilat erally (ar r ow s), indic at ing f ibrous c oalit ion.

F igure 24- 111 Ost eoc hondrit is desic c ans. A: T 1- w eight ed c oronal magnet ic resonanc e image show s a low signal int ensit y subart ic ular def ec t (ar r ow ) in t he medial f emoral c ondy le of t he lef t f emur. B: Inc reased signal int ensit y is not ed in t he subc hondral bone (ar r ow ) on f at - sat urat ed T 2- w eight ed image. T he absenc e of signal around t he f ragment implies lesion st abilit y .

P.1782

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3674

24 - Pediatric Applications Bone Infarction Bone inf arc t ion c an inv olv e t he subart ic ular or t he met adiaphy seal marrow of long bones. T he more c ommon c auses in c hildren inc lude sic kle c ell disease, st eroid t herapy , and Legg- Calv e- Pert hes disease (109). MRI has bec ome t he primary imaging examinat ion f or diagnosis of inf arc t ion. Ac ut e av asc ular nec rosis of t he f emoral head usually exhibit s a low signal int ensit y on T 1w eight ed images and high signal int ensit y on T 2- w eight ed images. Vary ing pat t erns of dev asc ularizat ion (homogeneous, het erogeneous, and ring) hav e been desc ribed. Ost eoc hondrit is dissec ans is a subart ic ular ost eonec rosis t hat of t en inv olv es t he f emoral c ondy les, part ic ularly t he medial c ondy le. T he nec rot ic f ragment of bone may or may not hav e int ac t ov erly ing c art ilage. F at - suppressed T 2-

w eight ed f ast spin ec ho and ST IR images are best f or show ing f luid w it hin t he subc hondral f ragment and adjac ent medullary bone (F ig. 24- 111). A high signal int ensit y int erf ac e on T 2- w eight ed images bet w een t he bone f ragment and nat iv e bone suggest s a loose f ragment . Know ledge of t he st abilit y of t he ost eoc hondral f ragment is import ant bec ause a loose f ragment may need t o be remov ed, w hereas an at t ac hed f ragment c an be t reat ed c onserv at iv ely . Ac ut e medullary bone inf arc t ion is seen as a region of low signal int ensit y on T 1- w eight ed images and high signal int ensit y on T 2- w eight ed images. Chronic inf arc t s may appear as a c ent ral area of high signal int ensit y , represent ing f at t y marrow , w it h a surrounding hy point ense rim, c orresponding t o reac t iv e bone (173,222).

REFERENCES 1. Abramson SJ. Adrenal neoplasms in c hildren. Radiol Clin Nor t h Am 1997;35:1415–1453. 2. Albaf ouille V, Say egh N, Coudenhov e S, et al. CT sc an pat t erns of pulmonary alv eolar prot einosis in c hildren. Pediat r Radiol 1999;29:147–152. 3. al- Nakshabandi N, Lingaw i S, Muller NL. Congenit al bronc hial at resia. Can Assoc Radiol J 2000;51:47–48. 4. Americ an Soc iet y of Anest hesiologist s T ask F orc e. Prac t ic e guidelines f or sedat ion and analgesia by non- anest hesiologist s: a report by t he Americ an Soc iet y of Anest hesiologist s T ask F orc e on sedat ion and analgesia by nonanest hesiologist s. Anest hesiology 1996;84:459–471.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3675

24 - Pediatric Applications 5. Anupindi S, Jaramillo D. Pediat ric magnet ic resonanc e imaging t ec hniques. Magn Reson Im aging Clin N Am 2002;10:189–207.

6. Argons GA, Kingsman KD, Wagner BJ, et al. Rhabdoid t umor of t he kidney in c hildren: a c omparison of 21 c ases. AJR Am J Roent genol 1997;168:447–451. 7. Argons GA, Wagner BJ, Dav idson AJ, et al. Mult iloc ular c y st ic renal t umor in c hildren: radiologic - pat hologic c orrelat ion. Radiogr aphic s 1995;15:654–669. 8. Argons GA, Wagner BJ, Lonergan GJ, et al. Genit ourinary rhabdomy osarc oma in c hildren: radiologic - pat hologic c orrelat ion. Radiogr aphic s 1997;17:919–937. P.1783 9. Assoun J, Ric hardi G, Railhac JJ, et al. Ost eoid ost eoma: MR imaging v ersus CT . Radiology 1994;191:217–223. 10. Av ila NA, Mueller BU, Carrasquillo JA, et al. Mult iloc ular t hy mic c y st s: imaging f eat ures in c hildren w it h human immunodef ic ienc y v irus inf ec t ion. Radiology 1996;201:130–134. 11. Av iram G, F ishman J, Y oung ML, et al. MR ev aluat ion of arrhy t hmogenic right v ent ric ular c ardiomy opat hy in pediat ric pat ient s. AJR Am J Roent genol 2003;180:1135–1141. 12. Barnew olt CE, Chung T . T ec hniques, c oils, pulse sequenc es, and c ont rast enhanc ement in pediat ric musc uloskelet al MR imaging. Magn Reson Im aging Clin N Am 1998;6:441–453. 13. Bass JE, Redqine MD, Kramer LA, et al. Spec t rum of c ongenit al anomalies of t he inf erior v ena c av a: c ross- sec t ional imaging f indings. Radiogr aphic s 2000;20:639–652. 14. Bass JE, Redw ine MD, Kramer LA, et al. Spec t rum of c ongenit al anomalies of t he inf erior v ena c av a: c ross- sec t ional imaging f indings. Radiogr aphic s 2000;20:639–652. 15. Beny a EC, Bulas DI, Eic helberger MR, et al. Splenic injury f rom blunt abdominal t rauma in c hildren: f ollow - up ev aluat ion w it h CT . Radiology 1995;195:685–688. 16. Berdon WE. Rings, slings, and ot her t hings: v asc ular c ompression of t he inf ant t rac hea updat ed f rom t he mid- c ent ury t o t he millennium—t he legac y of Robert E. Gross, MD, and Edw ard B. D. Neuhauser, MD. Radiology 2000;216:624–632. 17. Berger F H, Verst raet e KL, Gooding CA, et al. MR imaging of musc uloskelet al neoplasm. Magn Reson Im aging Clin N Am 2000;8:929–951.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3676

24 - Pediatric Applications 18. Bhalla S, Siegel MJ. Mult islic e c omput ed t omography in pediat ric s. In: Silv erman PM, ed. Mult islic e c om put ed t om ogr aphy : a pr ac t ic al appr oac h t o

c linic al pr ot oc ols. Philadelphia: Lippinc ot t Williams & Wilkins, 2002;231–282. 19. Bhargav a R, Parham DM, Lasat er OE, et al. MR imaging dif f erent iat ion of benign and malignant peripheral nerv e sheat h t umors: use of t he t arget sign. Pediat r Radiol 1997;27:124–129. 20. Bisset GS III. Hodgkin's disease. In: Siegel BA, Prot o AV, eds. Pediat r ic disease (f our t h ser ies) t est and sy llabus. Rest on, VA: Americ an College of Radiology , 1995:130–164. 21. Bisset GS. Anomalies of t he great v essels. In: Siegel BA, Prot o AV, eds. Pediat r ic disease (f our t h ser ies) t est and sy llabus. Rest on, VA: Americ an College of Radiology , 1995:198–219. 22. Bisset GS. MR imaging of sof t - t issue masses in c hildren. Magn Reson Im aging Clin N Am 1996;4:697–719. 23. Boec hat IN. MR imaging of t he pediat ric pelv is. Magn Reson Im aging Clin N Am 1996;4:679–697. 24. Borrello JA, Mirow it z SA, Siegel MJ. Neuroblast oma. In: Siegel BA, Prot o AV, eds. Pediat r ic disease (f our t h ser ies) t est and sy llabus. Rest on, VA: Americ an College of Radiology , 1993:640–665. 25. Bort hne A, Nordshus T , Reiset er T et al. MR urography : t he f ut ure gold st andard in paediat ric urogenit al imaging? Pediat r Radiol 1999;29:694–701. 26. Boxt LM. MR imaging of c ongenit al heart disease. Magn Reson Im aging Clin N Am 1996;4:327–359. 27. Brammer HM, Buc k JL, Hay es WS, et al. Malignant germ c ell t umors of t he ov ary : radiologic - pat hologic c orrelat ion. Radiogr aphic s 1990;10:715–724. 28. Brisse H, Pac quement H, Burdairon E, et al. Out c ome of residual mediast inal masses of t horac ic ly mphomas in c hildren: impac t on management and radiologic al f ollow - up st rat egy . Pediat r Radiol 1998;28:444–450. 29. Brodeur GM, Maris JM. Neuroblast oma. In: Dev it a VT , Hellman S, Rosenberg SA, eds. Canc er : pr inc iples and pr ac t ic e of onc ology . Philadelphia: Lippinc ot t Williams & Wilkins, 2001:895–933. 30. Broec ker B. Non- Wilms renal t umors in c hildren. Ur ol Clin Nor t h Am 2000;27:463–469. 31. Buet ow PC, Buc k JL, Pant ongrag- Brow n L, et al. Solid and papillary epit helial neoplasm of t he panc reas: imaging- pat hologic c orrelat ion in 56 c ases. Radiology 1996;199:707–711.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3677

24 - Pediatric Applications 32. Buet ow PC, Buc k JL, Pant ongrag- Brow n L, et al. Undif f erent iat ed (embry onal) sarc oma of t he liv er: pat hologic basis of imaging f indings in 28 c ases. Radiology 1997;203:779–783. 33. Cast leberry RP, Cushing B, Perlman E, et al. Germ c ell t umors. In: Pizzo PA, Poplac k DG, et al., eds. Pr inc iples and pr ac t ic e of pediat r ic onc ology . Philadelphia: Lippinc ot t –Rav en Publishers, 1997:921–945. 34. Chandra RS, St oc ker JT , Dehner LP. Liv er, gallbladder, and biliary t rac t . In: St oc ker JT , Dehner LP, eds. Pediat r ic pat hology . Philadelphia: J.B. Lippinc ot t Co., 1992:703–789. 35. Chang AB, Masel JP, Mast ers B. Post - inf ec t ious bronc hiolit is oblit erans: c linic al, radiologic al and pulmonary f unc t ion sequelae. Pediat r Radiol 1998;28:23–29. 36. Chepuri NB, St rouse PJ, Y anik GA. CT of renal ly mphoma in c hildren. AJR Am J Roent genol 2003;180:419–431. 37. Choe Y H, Kim Y M, Han BK, et al. MR imaging in t he morphologic diagnosis of c ongenit al heart disease. Radiogr aphic s 1997;17:403–422. 38. Choi BW, Park Y H, Choi JY , et al. Using elec t ron beam CT t o ev aluat e c onot runc al anomalies in pediat ric and adult pat ient s. AJR Am J Roent genol 2001;177:1045–1049.

39. Chung CJ, F ordham L, Lit t le S, et al. Int raperit oneal rhabdomy osarc oma in c hildren: inc idenc e and imaging c harac t erist ic s on CT . AJR Am J Roent genol 1998;170:1385–1387. 40. Chung CJ, Lorenzo R, Ray der S, et al. Rhabdoid t umors of t he kidney in c hildren: CT f indings. AJR Am J Roent genol 1995;164:697–700. 41. Cinar A, Haliloglu M, Kragoz T , et al. Int errupt ed aort ic arc h in a neonat e: mult idet ec t or CT diagnosis. Pediat r Radiol 2004; 34:901–903. 42. Clev eland RH. Congenit al lobar emphy sema. In: Siegel BA, Prot o AV, eds. Pediat r ic disease (f our t h ser ies) t est and sy llabus. Rest on, VA: Americ an College of Radiology , 1993:96–129. 43. Commit t ee on Drugs, Americ an Ac ademy of Pediat ric s. Guidelines f or monit oring and management of pediat ric pat ient s during and af t er sedat ion f or diagnost ic and t herapeut ic proc edures. Pediat r ic s 1992;89:1110–1115. 44. Connolly SA, Connolly LP, Jaramillo D. Imaging of sport s injuries in c hildren and adolesc ent s. Radiol Clin Nor t h Am 2001;39:773–790. 45. Cox T D, Wint ers WD, Weinberger E. CT of int ussusc ept ion in t he pediat ric pat ient : diagnosis and pit f alls. Pediat r Radiol 1996;26:26–32.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3678

24 - Pediatric Applications

46. Dav ey MS, Cohen MD. Imaging of gast roint est inal malignanc y in c hildhood. Radiol Clin Nor t h Am 1996;34:717–742. 47. Dav idson AJ, Choy ke PL, Hart man DS, et al. Renal medullary c arc inoma assoc iat ed w it h sic kle c ell t rait : radiologic f indings. Radiology 1995;195:83–85. 48. Demos T C, Posniak HV, Harmat h C, et al. Cy st ic lesions of t he panc reas. AJR Am J Roent genol 2002;179:1375–1388. 49. Demos T C, Posniak HV, Pierc e KL, et al. Venous anomalies of t he t horax. AJR Am J Roent genol 2004;182:1139–1150. 50. Dillon EH, Camput aro C. Part ial anomalous pulmonary v enous drainage of t he lef t upper lobe v s duplic at ion of t he superior v ena c av a: dist inc t ion based on CT f indings. AJR Am J Roent genol 1993;160:375–379. 51. Donaldson JS. Hemangioendot helioma of t he liv er. In: Siegel BA, Prot o AV, eds. Pediat r ic disease (f our t h ser ies) t est and sy llabus. Rest on, VA: Americ an College of Radiology , 1993: 436–462. 52. Donnelly LF , Bisset GS III. Pediat ric hepat ic imaging. Radiol Clin Nor t h Am 1998;36:413–427. 53. Donnelly LF , Emery KH, Brody AS, et al. Minimizing radiat ion dose f or pediat ric body applic at ions f or single- det ec t or helic al CT : st rat egies at a large c hildren's hospit al. AJR Am J Roent genol 2001;176:303–306. 54. Donnelly LF , F lec k RJ, Pac harn P, et al. Aberrant subc lav ian art eries: c ross- sec t ional imaging f indings in inf ant s and c hildren ref erred f or ev aluat ion of ext rinsic airw ay c ompression. AJR Am J Roent genol 2002;178:1269–1274. 55. Donnelly LF , Higgins CB. MR imaging of c onot runc al abnormalit ies. AJR Am J Roent genol 1996;166:925–928. 56. Donnelly LF , Klost erman LA. Pneumonia in c hildren: dec reased parenc hy mal c ont rast enhanc ement - CT sign of int ense illness and impending c av it ary nec rosis. Radiology 1997;205: 817–820. 57. Donnelly LF , Klost erman LA. T he y ield of CT of c hildren w ho hav e c omplic at ed pneumonia and nonc ont ribut ory c hest radiography . AJR Am J Roent genol 1998;170:1627–1631. 58. Donnelly LF , Morris CL. Ac ut e graf t - v ersus- host disease in c hildren: abdominal CT f indings. Radiology 1996;199:265–268. P.1784 59. Donnelly LF . Graf t - v ersus- host disease. In: Siegel BA, Siegel MJ, eds. Pediat r ic disease (f if t h ser ies) t est and sy llabus. Rest on, VA: Americ an College of Radiology , 2002:87–97.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3679

24 - Pediatric Applications 60. Donnelly LF . T arsal c oalit ion. In: Siegel BA, Siegel MJ, eds. Pediat r ic disease (f if t h ser ies) t est and sy llabus. Rest on, VA: Americ an College of Radiology , 2002;181–191. 61. Ec klund K, Jaramillo D. Imaging of grow t h dist urbanc e in c hildren. Radiol Clin Nor t h Am 2001;39:823–841.

62. F errozzi F , Bov a D, Draghi F , et al. CT F indings in primary v asc ular t umors of t he spleen. AJR Am J Roent genol 1996; 166:1097–1101. 63. F ielding JR. MR imaging of müllerian anomalies: impac t on t herapy . AJR Am J Roent genol 1996;167:1491–1495. 64. F let c her BD, Kast e SC. Magnet ic resonanc e imaging f or diagnosis and f ollow - up of genit ourinary , pelv ic , and perineal rhabdomy osarc oma. Ur ol Radiol 1992;14:262–272. 65. F let c her BD. Imaging pediat ric bone sarc omas. Radiol Clin Nor t h Am 1997;35:1477–1494. 66. F ranc o J, Aliaga R, Domingo ML, et al. Diagnosis of pulmonary sequest rat ion by spiral CT angiography . T hor ax 1998;53: 1089–1092. 67. F razier AA, Rosado de Christ enson ML, St oc ker JT et al. Int ralobar sequest rat ion: radiologic - pat hologic c orrelat ion. Radiogr aphic s 1997;17:725–745. 68. F riedland J, Siegel MJ. CT appearanc e of ac ut e appendic it is in c hildhood. AJR Am J Roent genol 1997;168:439–442. 69. F ront D, Ben- Haim S, Israel O, et al. Ly mphoma: predic t iv e v alue of Ga- 67 sc int igraphy af t er t reat ment . Radiology 1992; 182:359–363. 70. F rush DP, Bisset GS 3rd, Hall SC. Pediat ric sedat ion in radiology : t he prac t ic e of saf e sleep. AJR Am J Roent genol 1997;167: 1381–1387. 71. Geller E, Smergel E, Low ry P. Renal neoplasms of c hildhood. Radiol Clin Nor t h Am 1997;35:1391–1413. 72. Geret y BM. Hemoc hromat osis. In: F reeny PC, St ev enson GW, eds. Alim ent ar y t r ac t r adiology . St . Louis: Mosby , 1994:1560–1665. 73. Ghay e B, Szapiro D, F anc hamps J- M, et al. Congenit al bronc hial abnormalit ies rev isit ed. Radiogr aphic s 2001;21:105–119. 74. Ghossain MA, Buy NJ, Bazot M et al. CT in adnexal t orsion w it h emphasis on t ubal f indings: c orrelat ion w it h US. J Com put Assist T om ogr 1994;18:619–625. 75. Gilkeson RC, Cianc ibello L, Zahka K. Mult idet ec t or CT ev aluat ion of c ongenit al heart disease in pediat ric and adult pat ient s. AJR Am J Roent genol 2003;180:973–980.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3680

24 - Pediatric Applications 76. Gilkeson RC, Cianc ibello LM, Hejal RB, et al. T rac heobronc homalac ia dy namic airw ay ev aluat ion w it h mult idet ec t or CT . AJR Am J Roent genol 2001;176:205–210. 77. Goo HW, Park IS, Ko JK, et al. CT of c ongenit al heart disease: normal anat omy and t y pic al pat hologic c ondit ions. Radiogr aphic s 2003;23:S147–S165. 78. Green DM, Coppes MJ, Breslow NE, et al. Wilms t umor. In: Pizzo PA, Poplac k DG, eds. Pr inc iples and pr ac t ic e of pediat r ic onc ology . Philadelphia: Lippinc ot t –Rav en Publishers, 1997: 733–759. 79. Greenberg M, F iller RM. Hepat ic t umors. In: Pizzo PA, Poplac k DC, eds.

Pr inc iples and pr ac t ic e of pediat r ic onc ology . Philadelphia: Lippinc ot t –Rav en Publishers, 1997:717–732. 80. Gubernic k JA, Rosenberg HK, Ilaslan H, et al. US approac h t o jaundic e in inf ant s and c hildren. Radiogr aphic s 2000; 20:173–195. 81. Gupt a AK, Mit ra DK, Berry M, et al. Sonography and CT of panc reat oblast oma in c hildren. AJR Am J Roent genol 2000;174: 1639–1641. 82. Gupt a H, May o- Smit h WW, Mainiero MB, et al. Helic al CT of pulmonary v asc ular abnormalit ies. AJR Am J Roent genol 2002; 178:487–492. 83. Gut ierrez F R, Siegel MJ, F allah JH, et al. Magnet ic resonanc e imaging of c y anot ic and nonc y anot ic c ongenit al heart disease. Magn Reson Im aging Clin N Am 2002;10:209–235. 84. Gy ly s- Morin V, Hof f er F A, Kozakew ic h H, et al. Wilms t umor and nephroblast omat osis: imaging c harac t erist ic s at gadolinium- enhanc ed MR imaging. Radiology 1993;188:517–521. 85. Gy ly s- Morin VM. MR imaging of pediat ric musc uloskelet al inf lammat ory and inf ec t ious disorders. Magn Reson Im aging Clin N Am 1998;6:537–559. 86. Haaga JR. Comment ary . Radiat ion dose management : w eighing risk v ersus benef it . AJR Am J Roent genol 2001;177:289–291. 87. Haddon MJ, Bow en A. Bronc hopulmonary and neurent eric f orms of f oregut anomalies. Imaging f or diagnosis and management . Radiol Clin Nor t h Am 1991;29: 241–254. 88. Haliloglu M, Hof f er F A, Gronemey er SA, et al. Applic at ions of 3D c ont rast enhanc ed MR angiography in pediat ric onc ology . Pediat r Radiol 1999;29:863–868. 89. Hammric k- T urner JE, Saif MF , Pow ers CI, et al. Imaging of c hildhood nonHodgkin ly mphoma: assessment by hist ologic subt y pe. Radiogr aphic s 1994;14:11–28.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3681

24 - Pediatric Applications 90. Han T I, Kim MJ, Y oon HK, et al. Rhabdoid t umour of t he kidney : imaging f indings. Pediat r Radiol 2001;31:233–237. 91. Herman T E, Siegel MJ. CT of ac ut e spleen t orsion in c hildren w it h w andering spleen. AJR Am J Roent genol 1991;156:151–153.

92. Herman T E, Siegel MJ. CT of t he panc reas in c hildren. AJR Am J Roent genol 1991;157:375–379. 93. Hernandez RJ. Cardiov asc ular MR imaging of c hildren. Magn Reson Im aging Clin N Am 1996;4:615–636. 94. Hernandez RJ. Magnet ic resonanc e imaging of mediast inal v essels. Magn Reson Im aging Clin N Am 2002;10:237–251. 95. Higgins CB. Congenit al heart disease. In: Higgins CB, Hric ak H, Helms CA, eds. Magnet ic r esonanc e im aging of t he body , 3rd ed. Philadelphia: Lippinc ot t –Rav en Publishers, 1997:461–518. 96. Hof f man LV, Kuszy k BS, Mit c hell SE, et al. Angioarc hit ec t ure of pulmonary art eriov enous malf ormat ion: c harac t erizat ion using v olume- rendered 3D CT angiography . Car diov asc Int er v ent Radiol 2000;23:165–170. 97. Hopkins JK, Giles HW, Wy at t - Ashmead J, et al. Cy st ic nephroma. Radiogr aphic s 2004;24:589–593. 98. Hopkins KL, Pat ric k LE, Simoneaux SF , et al. Pediat ric great v essel anomalies: init ial c linic al experienc e w it h spiral CT angiography . Radiology 1996;200:811–815. 99. Hoppe H, Walder B, Sonnensc hein M, et al. Mult idet ec t or CT v irt ual bronc hosc opy t o grade t rac heobronc hial st enosis. AJR Am J Roent genol 2002;178:1195–2000. 100. Hort on KM, Bluemke DA, Hruban RH, et al. CT and MR imaging of benign hepat ic and biliary t umors. Radiogr aphic s 1999; 19:431–451. 101. Hubbard AM. Imaging of pediat ric hip disorders. Radiol Clin Nor t h Am 2001;39:721–732. 102. Hudson MM, Donaldson SS. Hodgkin's disease. In: Pizzo PA, Poplac k DG, eds. Pr inc iples and pr ac t ic e of pediat r ic onc ology , 3rd ed. Philadelphia: Lippinc ot t –Rav en Publishers, 1997:523–543. 103. Hugosson C, Mahr MA, Sabbah R. Primary unilat eral renal ly mphoblast ic ly mphoma. Pediat r Radiol 1997;27:23–25. 104. Ic hikaw a T , F ederle MP, Grazioli L, et al. F ibrolamellar hepat oc ellular c arc inoma: imaging and pat hologic f indings in 31 rec ent c ases. Radiology 1999;213:352–361.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3682

24 - Pediatric Applications 105. Irie H, Honda J, Jimi M, et al. Value of MR c holangiopanc reat ography in ev aluat ing c holedoc hal c y st s. AJR Am J Roent genol 1998;171:1381–1385. 106. Jabra AA, F ishman EK, T ay lor GA. CT f indings in inf lammat ory bow el disease in c hildren. AJR Am J Roent genol 1994;162: 975–979.

107. Jabra AA, F ishman EK, T ay lor GA. Hepat ic masses in inf ant s and c hildren: CT ev aluat ion. AJR Am J Roent genol 1992;158: 143–149. 108. Jabra AA, F ishman EK, T ay lor GA. Primary ov arian t umors in t he pediat ric pat ient : CT ev aluat ion. Clin Im aging 1993;17: 199–203. 109. Jaramillo D, Kasser JR, Villegas- Medina OL, et al. Cart ilaginous abnormalit ies and grow t h dist urbanc es in Legg- Calv é- Pert hes disease: ev aluat ion w it h MR imaging. Radiology 1995;197: 767–777. 110. Jaramillo D, Laor T , Gebhardt MC. Pediat ric musc uloskelet al neoplasms. Magn Reson Im aging Clin N Am 1996;4:749–770. 111. Jaramillo D, Laor T , Hof f er F A, et al. Epiphy seal marrow in inf anc y : MR imaging. Radiology 1991;180:809–812. 112. Jeong Y K, Ha HK, Y oon CH, et al. Gast roint est inal inv olv ement in Henoc hSc hönlein sy ndrome: CT f indings. AJR Am J Roent genol 1997;168:965–968. 113. Joseph AE, Donaldson JS, Rey nolds M. Nec k and t horax v enous aneury sm: assoc iat ion w it h c y st ic hy groma. Radiology 1989; 170:109–112. P.1785 114. Kabala JE, Shield J, Dunc an A. Renal c ell c arc inoma in c hildhood. Pediat r Radiol 1992;22:203–205. 115. Kaiser S, F innbogason T , Jorulf HK, et al. Suspec t ed appendic it is in c hildren: diagnosis w it h c ont rast - enhanc ed v ersus nonenhanc ed helic al CT . Radiology 2004;23:427–433. 116. Kast e SC, Y oung CW, Holmes T P, et al. Ef f ec t of helic al CT on t he f requenc y of sedat ion in pediat ric pat ient s. AJR Am J Roent genol 1997;168:1001–1003. 117. Kast e SC, Y oung CW. Saf e use of pow er injec t ors w it h c ent ral and peripheral v enous ac c ess dev ic es f or pediat ric CT . Pediat r Radiol 1995;26:499–501. 118. Kat z M, Konen E, Rozenman, et al. Spiral CT and 3D image rec onst ruc t ion of v asc ular rings and assoc iat ed t rac heobronc hial anomalies. J Com put Assist T om ogr 1995;19:564–568. 119. Kaw ashima A, Sandler CM, Corl F M, et al. Imaging of renal t rauma: a c omprehensiv e rev iew . Radiogr aphic s 2001;21:557–584.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3683

24 - Pediatric Applications 120. Kaw ashima A, Sandler CM, Goldman SM, et al. CT of renal inf lammat ory disease. Radiogr aphic s 1997;17:851–866.

121. Kesslar PJ, Buc k JL, Selby DM. Inf ant ile hemangioendot helioma of t he liv er rev isit ed. Radiogr aphic s 1993;13:657–670. 122. Kesslar PJ, Buc k JL, Suarez ES. Germ c ell t umors of t he sac roc oc c y geal region: radiologic - pat hologic c orrelat ion. Radiogr aphic s 1994;14:607–620. 123. Kim OH, Chung HJ, Choi BG. Imaging of t he c holedoc hal c y st . Radiogr aphic s 1995;15:69–88. 124. Kim T H, Kim Y M, Suh CH, et al. Helic al CT angiography and t hreedimensional rec onst ruc t ion of t ot al anomalous pulmonary v enous c onnec t ions in neonat es and inf ant s. AJR Am J Roent genol 2000;175:1381–1386. 125. Kim WS, Lee KS, Kim IO, et al. Congenit al c y st ic adenomat oid malf ormat ion of t he lung: CT - pat hologic c orrelat ion. AJR Am J Roent genol 1997;168:47–53. 126. King L, Siegel MJ, Balf e DM. Ac ut e panc reat it is in c hildren: CT f indings of int ra- and ext rapanc reat ic f luid c ollec t ions. Radiology 1995;195:196–200. 127. Kirc hner SG, Hernanz- Sc hulman M, St ein SM, et al. Imaging of pediat ric mediast inal hist oplasmosis. Radiogr aphic s 1991;11:365–381. 128. Ko SF , Ng SH, Lee T Y , et al. Noninv asiv e imaging of bronc hopulmonary sequest rat ion. AJR Am J Roent genol 2000;175:1005–1012. 129. Konen E, Merc hant N, Prov ost Y , et al. Coarc t at ion of t he aort a bef ore and af t er c orrec t ion. T he role of c ardiov asc ular MRI. AJR Am J Roent genol 2004;182:1333–1339. 130. Konen E, Rav iv - Zilka L, Cohen RA, et al. Congenit al pulmonary v enolobar sy ndrome: spec t rum of helic al CT f indings w it h emphasis on c omput erized ref ormat t ing. Radiogr aphic s 2003;23: 1175–1184. 131. Konez O, Burrow s PE. Magnet ic resonanc e imaging of v asc ular anomalies. Magn Reson Im aging Clin N Am 2002;10:363–388. 132. Kosuc u P, Ahmet oglu A, Koramaz I, et al. Low - dose MDCT and v irt ual bronc hosc opy in pediat ric pat ient s w it h f oreign body aspirat ion. AJR Am J Roent genol 2004;183:1171–1777. 133. Kot hari NA, Pelc hov it z DJ, Mey er JS. Imaging of musc uloskelet al inf ec t ions. Radiol Clin Nor t h Am 2001;39:653–671. 134. Kransdorf MJ, Moser RP Jr, Meis JM, et al. F at - c ont aining sof t - t issue masses of t he ext remit ies. Radiogr aphic s 1991;11:81–106. 135. Kuhn JP, Brody AS. High resolut ion CT of pediat ric lung disease. Radiol Clin Nor t h Am 2002;40:89–110.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3684

24 - Pediatric Applications 136. Lau DM, Siegel MJ, Hildebolt CF , et al. Bronc hiolit is oblit erans sy ndrome:

t hin- sec t ion CT diagnosis of obst ruc t iv e c hanges in inf ant s and y oung c hildren af t er lung t ransplant at ion. Radiology 1998;208:783–788. 137. Laut in EM, Rosenblat t M, F riedman AC, et al. Calc if ic at ion in non- Hodgkin ly mphoma oc c urring bef ore t herapy : ident if ic at ion on plain f ilms and CT . AJR Am J Roent genol 1990;155: 739–740. 138. Law ler LP, F ishman EK. Art eriov enous malf ormat ions and sy st emic lung supply : ev aluat ion by mult idet ec t or CT and t hree- dimensional v olume rendering. AJR Am J Roent genol 2002;178: 493–494. 139. Lee E, Siegel MJ, F oglia R. Ev aluat ion of angioarc hit ec t ure of pulmonary sequest rat ion in pediat ric pat ient s using 3D MDCT angiography . AJR Am J Roent genol 2004;183:183–188. 140. Lee E, Siegel MJ, Gut t ierez F , et al. Mult idet ec t or CT ev aluat ion of t horac ic aort ic anomalies in pediat ric pat ient s and y oung adult s: c omparison of t horac ic axial, mult iplanar, and 3D images. AJR Am J Roent genol 2004;182:777–784. 141. Lee E, Siegel MJ, Gut t ierez F , et al. Mult idet ec t or CT ev aluat ion of t horac ic aort ic anomalies in pediat ric pat ient s and y oung adult s: c omparison of t horac ic axial, mult iplanar, and 3D images. AJR Am J Roent genol 2004;182:777–784. 142. Leonidas JC, Berdon WE, Valderrama E, et al. Human immunodef ic ienc y v irus inf ec t ion and mult iloc ular t hy mic c y st s. Radiology 1996;198:377–379. 143. Lerner A, Branski D, Lebent al E. Panc reat ic diseases in c hildren. Pediat r Clin Nor t h Am 1996;43:125–156. 144. Loder RT , Kuhns LR, Sw inf ord AE. T he use of helic al c omput ed t omographic sc an t o assess bony phy seal bridges. J Pediat r Or t hop 1997;17:356–359. 145. Lonergan GJ, Mart inez- Leon MI, Agrons GA, et al. Nephrogenic rest s, nephroblast omat osis, and assoc iat ed lesions of t he kidney . Radiogr aphic s 1998;18:947–968. 146. Lonergan GJ, Ric e RR, Suarez ES. Aut osomal rec essiv e poly c y st ic kidney disease: radiologic - pat hologic c orrelat ion. Radiogr aphic s 2000;20:837–855. 147. Lonnergan GJ, Sc hw ab CM, Suarez ES, et al. Neuroblast oma, ganglioneuroblast oma and ganglioneuroma: radiologic - pat hologic c orrelat ion. Radiogr aphic s 2002;22:911–934. 148. Low e LH, Isuani BH, Heller RM, et al. Pediat ric renal masses: Wilms t umor and bey ond. Radiogr aphic s 2000;20:1585–1603.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3685

24 - Pediatric Applications

149. Luker GD, Siegel MJ. Mediast inal Hodgkin disease in c hildren: response t o t herapy . Radiology 1993;189:737–740. 150. Lumkin B, Anderson MW, Ablin DS, et al. CT , MRI, and c olor Doppler ult rasound c orrelat ion of panc reat oblast oma: a c ase report . Pediat r Radiol 1993;23:61–62. 151. Koh DM, Hansell DM. Comput ed t omography of dif f use int erst it ial lung disease in c hildren. Clin Radiol 2000;55:659–667. 152. Ly on RD, Mc Adams HP. Mediast inal bronc hogenic c y st : demonst rat ion of a f luid- f luid lev el at MR imaging. Radiology 1993; 186:427–428. 153. Ma LD, F rassic a F J, Bluemke DA, et al. CT and MRI ev aluat ion of musc uloskelet al inf ec t ion. Crit Rev Diagn Im aging 1997;36: 535–568. 154. Ma LD, F rassic a F J, Sc ot t WW Jr, et al. Dif f erent iat ion of benign and malignant musc uloskelet al t umors: pot ent ial pit f alls w it h MR imaging. Radiogr aphic s 1995;15:349–366. 155. Mac pherson RI. Gast roint est inal t rac t duplic at ions: c linic al, pat hologic , et iologic , and radiologic c onsiderat ions. Radiogr aphic s 1993;13:1063–1080. 156. Mazur J, Ross G, Cummings RJ, et al. Usef ulness of magnet ic resonanc e imaging f or t he diagnosis of ac ut e musc uloskelet al inf ec t ions in c hildren. J Pediat r Or t hop 1995;15:144–147. 157. Mc Adams HP, Rosado- de- Christ enson ML, Moran CA. Mediast inal hemangioma: radiographic and CT f eat ures in 14 pat ient s. Radiology 1994;193:399–402. 158. Mc Larney JK, Ruc ker PT , Bender GN, et al. F ibrolamellar c arc inoma of t he liv er: radiologic - pat hologic c orrelat ion. Radiogr aphic s 1999;19:453–471. 159. Medina LS, Siegel MJ, Glazer HS et al. Diagnosis of pulmonary c omplic at ions assoc iat ed w it h lung t ransplant at ion in c hildren: v alue of CT v s hist opat hologic st udies. AJR Am J Roent genol 1994;162:969–974. 160. Medina LS, Siegel MJ. CT of c omplic at ions in pediat ric lung t ransplant at ion. Radiogr aphic s 1994;14:1341–1349. 161. Mert en DF . Diagnost ic imaging of mediast inal masses in c hildren. AJR Am J Roent genol 1992;158:825–832. 162. Mey er JS, Harry MP, Mahboubi S, et al. Langerhans c ell hist ioc y t osis: present at ion and ev olut ion of radiologic f indings w it h c linic al c orrelat ion. Radiogr aphic s 1995;15:1135–1146. 163. Mey er JS, Hart y MP, Khademian Z. Imaging of neuroblast oma and Wilms t umor. Magn Reson Im aging Clin N Am 2002;10: 175–302.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3686

24 - Pediatric Applications 164. Mey er JS, Hof f er F A, Barnes PD, et al. Biologic al c lassif ic at ion of sof t t issue v asc ular anomalies: MR c orrelat ion. AJR Am J Roent genol 1991;157:559–564. 165. Mey er JS. Ret roperit oneal MR imaging in c hildren. Magn Reson Im aging Clin N Am 1996;4:657–678.

166. Meza MP, Benson M, Slov is T L. Imaging of mediast inal masses in c hildren. Radiol Clin Nor t h Am 1993;31:583–604. 167. Miller F H, F it zgerald SW, Donaldson JS. CT of t he azy goesophageal rec ess in inf ant s and c hildren. Radiogr aphic s 1993; 13:623–634. P.1786 168. Miller SL, Hof f er F A. Malignant and benign bone t umors. Radiol Clin Nor t h Am 2001;39:673–699. 169. Mirow it z SA. MR imaging art if ac t s. Challenges and solut ions. Magn Reson Im aging Clin N Am 1999;7:717–32. 170. Miy azaki T , Y amashit a Y , T ang Y , et al. Single- shot MR c holangiopanc reat ography of neonat es, inf ant s, and y oung c hildren. AJR Am J Roent genol 1998;170:33–37. 171. Miy azaki T , Y amashit a Y , T ang Y , et al. Single- shot MR c holangiopanc reat ography of neonat es, inf ant s, and y oung c hildren. AJR Am J Roent genol 1998;170:33–37. 172. Moon WK, Kin WS, Kim IO, et al. Dif f use pulmonary disease in c hildren: high- resolut ion CT f indings. AJR Am J Roent genol 1996;167:1405–1408. 173. Moore SG, Bisset GS, Siegel MJ, et al. Pediat ric musc uloskelet al MR imaging. Radiology 1991;179:345–360. 174. Morello F P, Donaldson JS. Nephroblast omat osis. In: Siegel BA, Prot o AV, eds. Pediat r ic disease (f our t h ser ies) t est and sy llabus. Rest on, VA: Americ an College of Radiology , 1993:584–615. 175. Mort ele K, Mergo PJ, Urrut ia M, et al. Dy namic gadolinium- enhanc ed MR f indings in inf ant ile hepat ic hemangioendot helioma. J Com put Assist T om ogr 1998;22:714–717. 176. Mort ele KJ, Ros PR. Imaging of dif f use liv er disease. Sem in Liv er Dis 2001;21:195–212. 177. Moult on JS, Blebea JS, Dunc o DM, et al. MR imaging of sof t - t issue masses: diagnost ic ef f ic ac y and v alue of dist inguishing bet w een benign and malignant lesions. AJR Am J Roent genol 1995;164:1191–1199.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3687

24 - Pediatric Applications 178. Mullins ME, Kirc her MF , Ry an DP, et al. Ev aluat ion of suspec t ed appendic it is in c hildren using limit ed helic al CT and c olonic c ont rast mat erial. AJR Am J Roent genol 2001;176:37–41.

179. Murakami T , Moc hizuki K, Nakamura H. Imaging ev aluat ion of t he c irrhot ic liv er. Sem in Liv er Dis 2001;21:213–224. 180. Nav oy JE, Roy al SA, Vaid Y N, et al. Wilms t umor: unusual manif est at ions. Pediat r Radiol 1995;25:S76–S86. 181. New man JS, F ranc is IR, Kaminski MS, et al. Imaging of ly mphoma w it h PET w it h 2- [F - 18]- f luoro- 2- deoxy - D- gluc ose: c orrelat ion w it h CT . Radiology 1994;190:111–116. 182. New man JS, New berg AH. Congenit al t arsal c oalit ion: mult imodalit y ev aluat ion w it h emphasis on CT and MR imaging. Radiogr aphic s 2000;20:321–332. 183. New man KD, Sc hisgall R, Rearman G, et al. Malignant mesenc hy moma of t he liv er in c hildren. J Pediat r Sur g 1989;24:781–783. 184. Nimkin K, T eeger S, Wallac h MT , et al. Adrenal hemorrhage in abused c hildren: imaging and post mort em f indings. AJR Am J Roent genol 1994;162:661–663. 185. Nunez D, Bec erra JL, F uent es D, et al. T raumat ic oc c lusion of t he renal art ery : helic al CT diagnosis. AJR Am J Roent genol 1996;167:777–780. 186. Oppenheim C, Mamou- Mani T , Say egh N, et al. Bronc hopulmonary dy splasia: v alue of CT in ident if y ing pulmonary sequelae. AJR Am J Roent genol 1994;163:169–172. 187. Pac harn P, Poe SA, Donnelly LF . Low - t ube c urrent mult idet ec t or CT f or c hildren w it h suspec t ed ext rinsic airw ay c ompression. AJR Am J Roent genol 2002;179:1523–1527. 188. Pappas JN, Donnelly LF , F rush DP. Reduc ed f requenc y of sedat ion of y oung c hildren using new mult i- slic e helic al CT . Radiology 2000;215:897–899. 189. Park HS, Im JG, Jung JW, et al. Anomalous lef t pulmonary art ery w it h c omplet e c art ilaginous ring. J Com put Assist T om ogr 1997;21:478–480. 190. Pat t erson A, F rush DP, Donnelly L. Helic al CT of t he body : are set t ings adjust ed f or pediat ric pat ient s. AJR Am J Roent genol 2001;176:297–301. 191. Pobeil RS, Bisset GS. Pic t orial essay : imaging of liv er t umors in t he inf ant and c hild. Pediat r Radiol 1995;25:495–506. 192. Pow ers C, Ros PR, St oupis C, et al. Primary liv er neoplasms: MR imaging w it h pat hologic c orrelat ion. Radiogr aphic s 1994;14: 459–482.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3688

24 - Pediatric Applications 193. Quillin SP, Siegel MJ. CT f eat ures of benign and malignant t erat omas in c hildren. J Com put Assist T om ogr 1992;16:723–726. 194. Quillin SP, Siegel MJ. CT f eat ures of benign and malignant t erat omas in c hildren. J Com put Assist T om ogr 1992;16:722–726. 195. Raw son JV, Siegel MJ. T ec hniques and st rat egies in pediat ric body MR imaging. Magn Reson Im aging Clin N Am 1996;4:589–598. 196. Remy J, Remy - Jardin M, Giraud F , et al. Angioarc hit ec t ure of pulmonary art eriov enous malf ormat ions: c linic al ut ilit y of t hree- dimensional helic al CT . Radiology 1994;191:657–664. 197. Remy - Jardin M, Remy J, May o JR, et al. T horac ic aort a. In: CT angiogr aphy of t he c hest . Philadelphia: Lippinc ot t Williams & Wilkins, 2001:29–50. 198. Riberio J, Ribeiro RC, F let c her BD. Imaging f indings in pediat ric adrenoc ort ic al c arc inoma. Pediat r Radiol 2000;30:45–51. 199. Rieumont MJ, Whit man GJ. Mesoblast ic nephroma. AJR Am J Roent genol 1994;162:76.

200. Roebuc k DJ, Y ang WT , Lam WWM, et al. Hepat obiliary rhabdomy osarc oma in c hildren: diagnost ic radiology . Pediat r Radiol 1998;28:101–108. 201. Roest AA, Helbing WA, v an der Wall EE. Post operat iv e ev aluat ion of c ongenit al heart disease by magnet ic resonanc e imaging. J Magn Reson Im aging 1999;10:656–666. 202. Rohrsc hneider WK, Weiric h A, Rieden K, et al. US, CT and MR imaging c harac t erist ic s of nephroblast omat osis. Pediat r Radiol 1998;28:435–443. 203. Rosado- de- Christ enson ML, F razier AA, St oc ker JT , et al. Ext ralobar sequest rat ion: radiologic - pat hologic c orrelat ion. Radiogr aphic s 1993;13:425–441. 204. Rosado- de- Christ enson ML, Pugat c h RD, Moran CA, et al. T hy molipoma: analy sis of 27 c ases. Radiology 1994;193:121–126. 205. Rosado- de- Christ enson ML, St oc ker JT . Congenit al c y st ic adenomat oid malf ormat ion. Radiogr aphic s 1991;11:865–886. 206. Rosado- de- Christ enson ML, T emplet on PA, Moran CA. Mediast inal germ c ell t umors: radiologic and pat hologic c orrelat ion. Radiogr aphic s 1992;12:1013–1030. 207. Rot ondo A, Sc ialpi M, Sc apat i C. Pulmonary art eriov enous malf ormat ion: ev aluat ion by MR angiography . AJR Am J Roent genol 1997;168:847–849. 208. Ruess L, F razier AA, Siv it C. CT of t he mesent ery , oment um, and perit oneum in c hildren. Radiogr aphic s 1995;15:89–104.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3689

24 - Pediatric Applications

209. Ruzal- Shapiro C, Berdon WE, Cohen MD, et al. MR imaging of dif f use bone marrow replac ement in pediat ric pat ient s w it h c anc er. Radiology 1991;181:587–589. 210. Ruzal- Shapiro C, Berdon WE, Cohen MD, et al. MR imaging of dif f use bone marrow replac ement in pediat ric pat ient s w it h c anc er. Radiology 1991;181:587–589. 211. Sanz N, de Mingo L, F lorez F , et al. Rhabdomy osarc oma of t he biliary t ree. Pediat r Sur g Int 1997;12:200–201. 212. Sav ader SJ, Benenat i JF , Venbrux AC, et al. Choledoc hal c y st s: c lassif ic at ion and c holangiographic appearanc e. AJR Am J Roent genol 1991;156:327–331. 213. Shad A, Magrat h I. Malignant non- Hodgkin's ly mphoma in c hildren. In: Pizzo PA, Poplac k DG, eds. Pr inc iples and pr ac t ic e of pediat r ic onc ology , 3rd ed. Philadelphia: Lippinc ot t –Rav en Publishers, 1997;545–587. 214. Shady KL, Siegel MJ, Brow n JJ. Preoperat iv e ev aluat ion of int raabdominal t umors in c hildren: gradient - rec alled ec ho v s spin- ec ho MR imaging. AJR Am J Roent genol 1993;161:843–847. 215. Siegel MJ, Bhallah S, Gut ierrez F , et al. Post - lung t ransplant at ion bronc hiolit is oblit erans: usef ulness of expirat ory t hin- sec t ion CT f or diagnosis. Radiology 2001;220:455–462. 216. Siegel MJ, Glazer HS, St . Amour T E, et al. Ly mphangiomas in c hildren: MR imaging. Radiology 1989;170:467–470. 217. Siegel MJ, Glazer HS, Wiener JI, et al. Normal and abnormal t hy mus in c hildhood: MR imaging. Radiology 1989;172:367–371. 218. Siegel MJ, Herman T E. Panc reat ic pseudoc y st . In: Siegel BA, Prot o AV, eds. Pediat r ic disease (f our t h ser ies) t est and sy llabus. Rest on, VA: Americ an College of Radiology , 1993:532–555. 219. Siegel MJ, Herman T E. Periport al low at t enuat ion at CT in c hildhood. Radiology 1992;183:685–688. 220. Siegel MJ, Hof f er F A. Magnet ic resonanc e imaging of nongy nec ologic pelv ic masses in c hildren. Magn Reson Im aging Clin N Am 2002;10:325–344. 221. Siegel MJ, Ishw aran H, F let c her B, et al. St aging of neuroblast oma w it h c omput ed t omography and magnet ic resonanc e imaging: report of t he Radiology Diagnost ic Onc ology Group. Radiology 2002;223:168–175. P.1787 222. Siegel MJ, Luker GD. Bone marrow imaging in c hildren. Magn Reson Im aging Clin N Am 1996;4:771–796.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3690

24 - Pediatric Applications 223. Siegel MJ, Luker GD. MR imaging of t he liv er in c hildren. Magn Reson Im aging Clin N Am 1996;4:637–656.

224. Siegel MJ, Suess C, Sc hmidt B, et al. Radiat ion dose and image qualit y in pediat ric CT : ef f ec t of t ec hnic al f ac t ors and phant om size and shape. Radiology 2004;233:515–522. 225. Siegel MJ, Weber CK. Cardiac and parac ardiac masses. In: Gut t ierez F R, Brow n JJ, Mirow it z SA, eds. Car diov asc ular m agnet ic r esonanc e im aging. St . Louis: Mosby –Y ear Book, 1992:112–123. 226. Siegel MJ. Ac ut e py elonephrit is. In: Siegel BA, Siegel MJ, eds. Pediat r ic disease (f if t h ser ies) t est and sy llabus. Rest on, VA: Americ an College of Radiology , 2002:71–97. 227. Siegel MJ. Adrenal glands, panc reas and ot her ret roperit oneal st ruc t ures. In: Siegel MJ, ed. Pediat r ic body CT . Philadelphia: Lippinc ot t Williams & Wilkins, 1999:253–286. 228. Siegel MJ. Diseases of t he t hy mus in c hildren and adolesc ent s. Post gr ad Radiol 1993;13:106–132. 229. Siegel MJ. Gast roint est inal t rac t . In: Siegel MJ, ed. Pediat r ic body CT . Philadelphia: Lippinc ot t Williams & Wilkins, 1999:201–225. 230. Siegel MJ. Hemat oma. In: Siegel BA, Siegel MJ, eds. Magnet ic r esonanc e im aging (sec ond ser ies) t est and sy llabus. Rest on, VA: Americ an College of Radiology , 2000:1–16. 231. Siegel MJ. Hepat ic f rac t ure w it h hy pov olemic shoc k. In: Siegel BA, Prot o AV, eds. Pediat r ic disease (f our t h ser ies) t est and sy llabus. Rest on, VA: Americ an College of Radiology , 1993:490–508. 232. Siegel MJ. Leukemia. In: Siegel BA, Choplin RH, Siegel MJ, et al., eds. Body MRI t est and sy llabus. Rest on, VA: Americ an College of Radiology , 2000:173–189. 233. Siegel MJ. Liv er and biliary t rac t . In: Siegel MJ, ed. Pediat r ic body CT . Philadelphia: Lippinc ot t Williams & Wilkins, 1999: 141–174. 234. Siegel MJ. Lung, pleural and c hest w all. In: Pediat r ic body CT . Philadelphia: Lippinc ot t Williams & Wilkins, 1999:101–140. 235. Siegel MJ. Magnet ic resonanc e imaging of musc uloskelet al sof t t issue masses. Radiol Clin Nor t h Am 2001;39:701–720. 236. Siegel MJ. Magnet ic resonanc e imaging of t he adolesc ent f emale pelv is. Magn Reson Im aging Clin N Am 2002;10:303–324. 237. Siegel MJ. Mediast inum. In: Siegel MJ, ed. Pediat r ic body CT . Philadelphia: Lippinc ot t Williams & Wilkins, 1999:65–100.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3691

24 - Pediatric Applications 238. Siegel MJ. MR imaging of pediat ric abdominal neoplasms. Magn Reson Im aging Clin N Am 2000;8:837–851. 239. Siegel MJ. MRI of t he pediat ric abdomen. Magn Reson Im aging Clin N Am 1995;3:161–182. 240. Siegel MJ. Mult iplanar and t hree- dimensional row CT of t horac ic v essels and airw ay s in t he pediat ric populat ion. Radiology 2003;229:641–650. 241. Siegel MJ. Musc uloskelet al sy st em and spine. In: Siegel MJ, ed. Pediat r ic body CT . Philadelphia: Lippinc ot t Williams & Wilkins, 1999:312–345. 242. Siegel MJ. Pediat ric c hest applic at ions. In: F ishman EK, Jef f rey B, eds. Mult islic e helic al CT , 3rd ed. Philadelphia: Lippinc ot t Williams & Wilkins, 2003:159–182.

243. Siegel MJ. Pediat ric urinary t rac t inf ec t ion. In: Pollac k HM, Mc Clennan BL, eds. Clinic al ur ogr aphy . Philadelphia: WB Saunders, 2000:1103–1121. 244. Siegel MJ. Pelv ic organs and sof t t issues. In: Siegel MJ, ed. Pediat r ic body CT . Philadelphia: Lippinc ot t Williams & Wilkins, 1999:287–311. 245. Siegel MJ. Pelv ic t umors. Radiol Clin Nor t h Am 1997;35: 1455–1475. 246. Siegel MJ. Spleen, perit oneum and abdominal w all. In: Siegel MJ, ed. Pediat r ic body CT . Philadelphia, PA: Lippinc ot t Williams & Wilkins, 1999:175–200. 247. Siegel MJ. T ec hniques. In: Siegel MJ, ed. Pediat r ic body CT . Philadelphia: Lippinc ot t Williams & Wilkins, 1999:1–41. 248. Siegel MJ. T he c hild w it h abdominal t rauma. In: Hilt on SVW, Edw ards DK. Pr ac t ic al pediat r ic r adiology , 3rd ed. Philadelphia: W.B. Saunders Co., 2005. In press. 249. Siegel MJ. T he kidney . In: Siegel MJ, ed. Pediat r ic body CT . Philadelphia: Lippinc ot t Williams & Wilkins, 1999:226–252. 250. Siegel MJ. T horac oabdominal t rauma. In: Siegel MJ, ed. Pediat r ic body CT . Philadelphia: Lippinc ot t Williams & Wilkins, 1999: 346–371. 251. Sisler CL, Siegel, MJ. Malignant rhabdoid t umor of t he kidney : radiologic f eat ures. Radiology 1989;172:211–212. 252. Siv it CJ, Cut t ing JP, Eic helberger MR. CT diagnosis and loc alizat ion of rupt ure of t he bladder in c hildren w it h blunt abdominal t rauma: signif ic anc e of c ont rast mat erial ext rav asat ion in t he pelv is. AJR Am J Roent genol 1995;164:1243–1246. 253. Siv it CJ, Eic helberger MR, T ay lor GA, et al. Blunt panc reat ic t rauma in c hildren: CT diagnosis. AJR Am J Roent genol 1992;158: 1097–1100.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3692

24 - Pediatric Applications 254. Siv it CJ, Ingram JD, T ay lor GA, et al. Post - t raumat ic adrenal hemorrhage in c hildren: CT f indings in 34 pat ient s. AJR Am J Roent genol 1992;158:1299–1302.

255. Siv it CJ, T ay lor GA, Bulas DI, et al. Blunt t rauma in c hildren: signif ic anc e of perit oneal f luid. Radiology 1991;178:185–188. 256. Siv it CJ, T ay lor GA, Bulas DI, et al. Post t raumat ic shoc k in c hildren: CT f indings assoc iat ed w it h hemody namic inst abilit y . Radiology 1992;182:723–726. 257. Siv it CJ, T ay lor GA, New man KD. Saf et y - belt injuries in c hildren w it h lapbelt ec c hy mosis: CT f indings in 61 pat ient s. AJR Am J Roent genol 1991;157:111–114. 258. Siv it CJ. Siegel MJ, Applegat e KE, et al. Spec ial f oc us session. When appendic it is is suspec t ed in c hildren. Radiogr aphic s 2001;21:247–262. 259. Slov is T L. T he ALARA c onc ept in pediat ric CT : my t h or realit y . Radiology 2002;223:5–6. 260. Sof ka CM, Semelka RC, Kelekis NL, et al. Magnet ic resonanc e imaging of neuroblast oma using c urrent t ec hniques. Magn Reson Im aging 1999;17: 193–198. 261. Sorant in E, Geiger B, Lindbic hler F , et al. CT based v irt ual t rac heobronc hosc opy in c hildren—c omparison w it h axial CT and mult iplanar rec onst ruc t ions: preliminary result s. Pediat r Radiol 2002;32:8–15. 262. Soy er P, Spelle L, Pelage JP, et al. Cy st ic f ibrosis in adolesc ent s and adult s: f at t y replac ement of t he panc reas—CT ev aluat ion and f unc t ional c orrelat ion. Radiology 1999;210:611–615. 263. Spiers AS, Husband JES, Mac Vic ar AD. T reat ed t hy mic ly mphoma: c omparison of MR imaging w it h CT . Radiology 1997;203: 369–376. 264. St at es LJ, Bellah RD. Imaging of t he pediat ric f emale pelv is. Sem in Roent genol 1996;31:312–329. 265. St ev ens WR, Johnson CD, St ephens DH, et al. F ibrolamellar hepat oc ellular c arc inomas: st age at present at ion and result s of aggressiv e surgic al management . AJR Am J Roent genol 1995;164: 1153–1158. 266. St oupis C, Ros PR, Abbit t PL, et al. Bubbles in t he belly : imaging of c y st ic mesent eric or oment al masses. Radiogr aphic s 1994;14: 729–737. 267. St rouse PJ, Close BJ, Marshall KW, et al. CT of bow el and mesent eric t rauma in c hildren. Radiogr aphic s 1999;19: 1237–1250. 268. St rouse PJ. Magnet ic resonanc e angiography of t he pediat ric abdomen and pelv is. Magn Reson Im aging Clin N Am 2002;10: 345–361.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3693

24 - Pediatric Applications 269. T ac c one A, Oddone M, Dell'Ac qua A, et al. MRI “ road- map” of normal age- relat ed bone marrow . Pediat r Radiol 1995;25: 596–606.

270. T akahashi K, Inasoka T , Murakami N, et al. Charac t erizat ion of t he normal and hy perplast ic t hy mus on c hemic al- shif t MR imaging. AJR Am J Roent genol 2003;180:1265–1269. 271. T ay lor GA, Kauf man RA, Siv it CJ. Ac t iv e hemorrhage in c hildren af t er t horac oabdominal t rauma: c linic al and CT f eat ures. AJR Am J Roent genol 1994;162:401–404. 272. T ay lor GA. Imaging of pediat ric blunt abdominal t rauma: w hat hav e w e learned in t he past dec ade? Radiology 1995;195: 600–601. 273. T eo EL, St rouse PJ, Princ e MR. Applic at ions of magnet ic resonanc e imaging and magnet ic resonanc e angiography t o ev aluat e t he hepat ic v asc ulat ure in t he pediat ric pat ient . Pediat r Radiol 1999;29:238–243. 274. T rojiano RN, Mc Cart hy SM. Mullerian duc t anomalies: imaging and c linic al issues. Radiology 2004;233:19–34. 275. Urrut ia M, Mergo PJ, Ros LH, et al. Cy st ic masses of t he spleen: radiologic - pat hologic c orrelat ion. Radiogr aphic s 1996;16:107–129. P.1788 276. Vade A, Rey es H, Wilbur A, et al. T he anorec t al sphinc t er af t er rec t al pull- t hrough surgery f or anorec t al anomalies: MRI ev aluat ion. Pediat r Radiol 1989;19:179–183. 277. Van Praagh S, Carrera ME, Sanders S, et al. Part ial or t ot al direc t pulmonary v enous drainage t o t he right at rium due t o malposit ion of sept um primum. Chest 1995;107:1488–1498. 278. Vaughn DD, Jabra AA, F ishman EK. Panc reat ic disease in c hildren and y oung adult s: ev aluat ion w it h CT . Radiogr aphic s 1998;18:1171–1187. 279. Vogler JB III, Murphy WA. Bone marrow imaging. Radiology 1998;168:679–693. 280. Wadsw ort h DT , New man B, Abramson SJ, et al. Splenic ly mphangiomat osis in c hildren. Radiology 1997;202:173–176. 281. Wait c hes G, Zaw in JK, Poznanski AK. Sequenc e and rat e of bone marrow c onv ersion in t he f emora of c hildren as seen on MR imaging: are ac c ept ed st andards ac c urat e? AJR Am J Roent genol 1994;162:1399–1406. 282. Wec hsler RJ, Sc hw eit zer ME, Deely DM, et al. T arsal c oalit ion: depic t ion and c harac t erizat ion w it h CT and MR imaging. Radiology 1994;193:447–452.

Computed Body Tomography with MRI Correlation , 4th Edition

© 2017 Enter your company name

3694

24 - Pediatric Applications 283. West ra SJ, Hill JA, Alejos JC, et al. T hree- dimensional helic al CT of pulmonary art eries in inf ant s and c hildren w it h c ongenit al heart disease. AJR Am J Roent genol 1999;173:109–115. 284. West ra SJ, Zaninov ic AC, Hall T R, et al. Imaging of t he adrenal gland in c hildren. Radiogr aphic s 1994;14:1323–1340. 285. Woodring JH, How ard T A, Kanga JF . Congenit al pulmonary v enolobar sy ndrome rev isit ed. Radiogr aphic s 1994;14:349–369. 286. Wu JW, Whit e CS, Mey er CA, et al. Variant bronc hial anat omy : CT appearanc e and c lassif ic at ion. AJR Am J Roent genol 1999;172:741–744. 287. Y amashit a Y , Hat anka Y , T orashima M et al. Mat ure c y st ic t erat omas of

t he ov ary w it hout f at in t he c y st ic c av it y : MR f eat ures in 12 c ases. AJR Am J Roent genol 1994;163:613–616. 288. Zerin JM, DiPiet ro MA. Mesent eric v asc ular anat omy at CT : normal and abnormal appearanc es. Radiology 1991;179:739–742. 289. Zobel MS, Borrello J, Siegel MJ, et al. Pediat ric knee MR imaging: pat t ern of injuries in t he immat ure skelet on. 1994;190:397–401. P.1789

Appendices

PROTOCOLS PROTOC OL 1 INDIC ATION:

Ex te nt Sc a nne r se ttings

De te c tor c ollima tion

Pitc h

Slic e re c onstruc tion thic kne ss IV C ontra st C ontra st v olume C ontra st inje c tion ra te

Computed Body Tomography with MRI Correlation , 4th Edition

Sta nda rd Lung/Me dia stinum (onc ologic st aging, det ec t ion of met ast ases, c harac t erizat ion of mediast inal or pulmonary mass, ev aluat ion of t rauma) Lung apic es t o c audal bases kVp: 80 f or pat ient s w eighing