Diagnostic imaging. Cardiovascular [2 ed.] 9781931884747, 1931884749

Table of contents :
Contents
Editors
Dedication
Foreword
Preface
Acknowledgments
Section 1 - Introduction and Overview
Cardiac CT: Acquisition and Postprocessing Indications and Interpretation
Cardiac MR: Acquisition and Imaging Protocols
Cardiac Anatomy
Section 2 - Congenital
Approach to Congenital Heart Disease
Coarctation of Aorta
Double Aortic Arch
Right Aortic Arch
Persistent Fifth Arch
Pulmonary Sling
D-Transposition of Great Arteries
L-Transposition of Great Arteries
Truncus Arteriosus
Pulmonary Atresia
Hypoplastic Left Heart Syndrome
Heterotaxia Syndromes
Ebstein Anomaly
Cor Triatriatum
Tetralogy of Fallot
Tetralogy of Fallot Palliation: BT Shunt
Tetralogy of Fallot: Definitive Repair
Proximal Interruption of Pulmonary Artery
Section 3 - Shunts
Approach to Shunts
Patent Ductus Arteriosus
Atrial Septal Defects
Ventricular Septal Defects
Endocardial Cushion Defect
Scimitar Syndrome
Total Anomalous Pulmonary Venous Return
Partial Anomalous Pulmonary Venous Return
Section 4 - Valvular
Approach to Valvular Disease
Aortic Stenosis
Transcatheter Aortic Valve Replacement
Aortic Regurgitation
Bicuspid Aortic Valve
Mitral Stenosis
Mitral Valve Prolapse
Mitral Regurgitation
Mitral Annular Calcification
Pulmonary Stenosis
Pulmonary Regurgitation
Tricuspid Stenosis
Tricuspid Regurgitation
Infective Endocarditis
Valvular Prosthesis
Prosthetic Valve Complications
Carcinoid Syndrome
Multivalvular Disease
Rheumatic Heart Disease
Left Ventricular Apical Aortic Conduit
Section 5 - Pericardial
Approach to Pericardial Disease
Pericardial Anatomy
Infectious Pericarditis
Uremic Pericarditis
Neoplastic Pericarditis
Constrictive Pericarditis
Pericardial Cyst
Absent Pericardium
Pericardial Effusion
Pericardial Tamponade
Section 6 - Neoplastic
Approach to Neoplastic Disease
Metastatic Disease
Tumor Extension Into the Atria
Atrial Myxoma
Cardiac Lipoma
Cardiac Thrombus
Cardiac Sarcoma
Tumor Mimics
Hemangioma
Papillary Fibroelastoma
Fibroma
Lipomatous Hypertrophy, Interatrial Septum
Lymphoma
Section 7 - Cardiomyopathy
Imaging of Cardiomyopathies: The Evidence
Hypertrophic Cardiomyopathy
Ischemic Cardiomyopathy
Nonischemic Dilated Cardiomyopathy
Restrictive Cardiomyopathy
Myocarditis
Arrhythmogenic RV Dysplasia/Cardiomyopathy
Endomyocardial Fibrosis
Hypereosinophilic Syndrome
Cardiac Sarcoidosis
Cardiac Amyloidosis
Left Ventricular Noncompaction
Chagas Disease
Iron Overload Syndromes
Takotsubo Cardiomyopathy
Section 8 - Coronary Artery Disease
Approach to Coronary Heart Disease
Coronary Anatomy
Anomalous Left Coronary Artery, Malignant
Anomalous Left Coronary Artery, Benign
Anomalous LCX
Anomalous RCA
Bland-White-Garland Syndrome
Coronary Embolism
Coronary Artery Aneurysm
Coronary Calcification
Coronary Atherosclerotic Plaque
Coronary Thrombosis
Coronary Artery Stenosis
Ischemia RCA Stenosis
Left Main Coronary Stenosis
Coronary Artery Dissection
Acute Myocardial Infarction
Chronic Myocardial Infarction
Infarction LAD Distribution
Papillary Muscle Rupture
Right Ventricular Infarction
Nonatherosclerosis Myocardial Infarction
Nontransmural Myocardial Infarction
Post-Infarction LV Aneurysm
Post-Infarction LV Pseudoaneurysm
Post-Infarction Mitral Regurgitation
Left Ventricular Free Wall Rupture
Ventricular Septal Rupture
Post-Angioplasty Restenosis
In-Stent Restenosis
Post-CABG Thrombosis
Post-CABG Atherosclerosis
Myocardial Bridge
Coronary Fistula
Section 9 - Heart Failure
Approach to Heart Failure
Right Heart Failure
Left Heart Failure
Heart Transplant
Ventricular Assist Devices
Left Ventricular Hypertrophy
Right Ventricular Hypertrophy
PVH/Pulmonary Edema (Cardiogenic)
Cor Pulmonale
Section 10 - Electrophysiology
Imaging Before and After Electrophysiology Procedures
Pulmonary Vein Mapping
Pulmonary Vein Stenosis
Pacemakers/ICDs
Cardiac Vein Mapping
Left Atrial Thrombus
Section 11 - Pulmonary Vasculature
Approach to Pulmonary Vasculature
Pulmonary Arteriovenous Malformation
Pulmonary Artery Pseudoaneurysm
Pulmonary Artery Aneurysm
Acute Pulmonary Embolism
Chronic Pulmonary Embolism
Pulmonary Sequestration
Branch Pulmonary Artery Stenosis
Pulmonary Arterial Hypertension
Pulmonary Venoocclusive Disease
Section 12 - Arterial
Introduction and Overview
Approach to Congenital and Acquired Diseases of the Aorta
Approach to Acute Aortic Syndrome
Thoracic Aorta and Great Vessels
Thoracic Aorta and Great Vessel Anatomy
Thoracic Aortic Aneurysm
Mycotic Aneurysm
Chronic Post-Traumatic Pseudoaneurysm
Aortic Intramural Hematoma
Penetrating Atherosclerotic Ulcer
Aortic Dissection
Takayasu Arteritis
Giant Cell Arteritis
Marfan Syndrome
Pseudocoarctation
Traumatic Aortic Laceration
Ductus Diverticulum
Abdominal Aorta and Visceral Vasculature
Abdominal Aorta and Visceral Vasculature Anatomy
Abdominal Aortic Aneurysm
AAA With Rupture
Aortic Graft Complications
Abdominal Aortic Occlusion
Section 13 - Venous
Approach to Venous Conditions
Venous Anatomy
Superior Vena Cava Syndrome
Inferior Vena Cava Anomalies
Inferior Vena Cava Occlusion
Left Superior Vena Cava
Azygos Continuation of the IVC
May-Thurner Syndrome
Nutcracker Syndrome
Section 14 - Extracranial Cerebral Arteries
Approach to Extracranial Cerebral Arteries
Acute Ischemic Stroke
Atherosclerosis, Extracranial
Carotid Stenosis, Extracranial
Carotid Dissection
Carotid Pseudoaneurysm, Extracranial
Vertebral Dissection
Subclavian Steal Syndrome
Section 15 - Renal Vasculature
Approach to Renal Vasculature
Renal Vasculature Anatomy
Renal Artery Atherosclerosis
Fibromuscular Dysplasia, Renal
Polyarteritis Nodosa
Renal Arteriovenous Fistula
Renal Vein Thrombosis
Section 16 - Peripheral Vasculature
Introduction and Overview
Approach to Peripheral Vasculature
Lower Extremity Vasculature Anatomy
Vasculature of the Trunk
Subclavian Artery Stenosis/Occlusion
Subclavian Vein Thrombosis
Iliac Artery Occlusive Disease
Iliac Artery Aneurysmal Disease
Lower Extremity Vasculature
Lower Extremity Aneurysms
Acute Lower Extremity Ischemia
Femoropopliteal Artery Occlusive Disease
Cystic Adventitial Disease
Persistent Sciatic Artery
Arteriovenous Fistula
Deep Vein Thrombosis
Index
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Citation preview

Diagnostic Imaging Cardiovascular

1

Diagnostic Imaging Cardiovascular

Contents Editors ........................................................................................................................................................................ 6 Dedication .............................................................................................................................................................. 9 Foreword ................................................................................................................................................................ 9 Preface ..................................................................................................................................................................10 Acknowledgments..................................................................................................................................................10 Section 1 - Introduction and Overview........................................................................................................................11 Cardiac CT: Acquisition and Postprocessing Indications and Interpretation .............................................................11 Cardiac MR: Acquisition and Imaging Protocols ......................................................................................................19 Cardiac Anatomy ....................................................................................................................................................28 Section 2 - Congenital ................................................................................................................................................73 Approach to Congenital Heart Disease....................................................................................................................73 Coarctation of Aorta...............................................................................................................................................84 Double Aortic Arch .................................................................................................................................................93 Right Aortic Arch .................................................................................................................................................. 102 Persistent Fifth Arch ............................................................................................................................................. 111 Pulmonary Sling ................................................................................................................................................... 114 D-Transposition of Great Arteries ......................................................................................................................... 123 L-Transposition of Great Arteries .......................................................................................................................... 129 Truncus Arteriosus ............................................................................................................................................... 135 Pulmonary Atresia................................................................................................................................................ 141 Hypoplastic Left Heart Syndrome ......................................................................................................................... 147 Heterotaxia Syndromes ........................................................................................................................................ 153 Ebstein Anomaly .................................................................................................................................................. 162 Cor Triatriatum .................................................................................................................................................... 171 Tetralogy of Fallot ................................................................................................................................................ 174 Tetralogy of Fallot Palliation: BT Shunt ................................................................................................................. 183 Tetralogy of Fallot: Definitive Repair..................................................................................................................... 186 Proximal Interruption of Pulmonary Artery ........................................................................................................... 194 Section 3 - Shunts .................................................................................................................................................... 200 Approach to Shunts .............................................................................................................................................. 200 Patent Ductus Arteriosus ...................................................................................................................................... 203 Atrial Septal Defects ............................................................................................................................................. 212 Ventricular Septal Defects .................................................................................................................................... 221 Endocardial Cushion Defect .................................................................................................................................. 230 Scimitar Syndrome ............................................................................................................................................... 236 Total Anomalous Pulmonary Venous Return ......................................................................................................... 242 Partial Anomalous Pulmonary Venous Return ....................................................................................................... 248 Section 4 - Valvular .................................................................................................................................................. 251 Approach to Valvular Disease ............................................................................................................................... 251 Aortic Stenosis ..................................................................................................................................................... 259 Transcatheter Aortic Valve Replacement .............................................................................................................. 265 Aortic Regurgitation ............................................................................................................................................. 270 Bicuspid Aortic Valve ............................................................................................................................................ 276 Mitral Stenosis ..................................................................................................................................................... 282 Mitral Valve Prolapse ........................................................................................................................................... 288 Mitral Regurgitation ............................................................................................................................................. 294 Mitral Annular Calcification .................................................................................................................................. 300 Pulmonary Stenosis .............................................................................................................................................. 306 Pulmonary Regurgitation...................................................................................................................................... 312 Tricuspid Stenosis................................................................................................................................................. 317 Tricuspid Regurgitation ........................................................................................................................................ 321 Infective Endocarditis ........................................................................................................................................... 326 Valvular Prosthesis ............................................................................................................................................... 332 Prosthetic Valve Complications............................................................................................................................. 341 Carcinoid Syndrome ............................................................................................................................................. 347 Multivalvular Disease ........................................................................................................................................... 353 2

Diagnostic Imaging Cardiovascular Rheumatic Heart Disease ..................................................................................................................................... 361 Left Ventricular Apical Aortic Conduit ................................................................................................................... 367 Section 5 - Pericardial............................................................................................................................................... 372 Approach to Pericardial Disease ........................................................................................................................... 372 Pericardial Anatomy ............................................................................................................................................. 380 Infectious Pericarditis ........................................................................................................................................... 388 Uremic Pericarditis ............................................................................................................................................... 395 Neoplastic Pericarditis .......................................................................................................................................... 398 Constrictive Pericarditis........................................................................................................................................ 404 Pericardial Cyst .................................................................................................................................................... 410 Absent Pericardium .............................................................................................................................................. 416 Pericardial Effusion .............................................................................................................................................. 419 Pericardial Tamponade......................................................................................................................................... 428 Section 6 - Neoplastic............................................................................................................................................... 434 Approach to Neoplastic Disease ........................................................................................................................... 434 Metastatic Disease ............................................................................................................................................... 443 Tumor Extension Into the Atria ............................................................................................................................. 449 Atrial Myxoma ..................................................................................................................................................... 455 Cardiac Lipoma..................................................................................................................................................... 461 Cardiac Thrombus ................................................................................................................................................ 467 Cardiac Sarcoma .................................................................................................................................................. 476 Tumor Mimics ...................................................................................................................................................... 485 Hemangioma........................................................................................................................................................ 490 Papillary Fibroelastoma ........................................................................................................................................ 496 Fibroma ............................................................................................................................................................... 499 Lipomatous Hypertrophy, Interatrial Septum ........................................................................................................ 505 Lymphoma ........................................................................................................................................................... 514 Section 7 - Cardiomyopathy ..................................................................................................................................... 520 Imaging of Cardiomyopathies: The Evidence ......................................................................................................... 520 Hypertrophic Cardiomyopathy ............................................................................................................................. 528 Ischemic Cardiomyopathy .................................................................................................................................... 537 Nonischemic Dilated Cardiomyopathy .................................................................................................................. 543 Restrictive Cardiomyopathy ................................................................................................................................. 549 Myocarditis .......................................................................................................................................................... 555 Arrhythmogenic RV Dysplasia/Cardiomyopathy .................................................................................................... 561 Endomyocardial Fibrosis....................................................................................................................................... 567 Hypereosinophilic Syndrome ................................................................................................................................ 573 Cardiac Sarcoidosis............................................................................................................................................... 579 Cardiac Amyloidosis ............................................................................................................................................. 584 Left Ventricular Noncompaction ........................................................................................................................... 590 Chagas Disease..................................................................................................................................................... 596 Iron Overload Syndromes ..................................................................................................................................... 601 Takotsubo Cardiomyopathy.................................................................................................................................. 607 Section 8 - Coronary Artery Disease.......................................................................................................................... 613 Approach to Coronary Heart Disease .................................................................................................................... 613 Coronary Anatomy ............................................................................................................................................... 615 Anomalous Left Coronary Artery, Malignant ......................................................................................................... 628 Anomalous Left Coronary Artery, Benign .............................................................................................................. 631 Anomalous LCX .................................................................................................................................................... 636 Anomalous RCA.................................................................................................................................................... 639 Bland-White-Garland Syndrome ........................................................................................................................... 642 Coronary Embolism .............................................................................................................................................. 644 Coronary Artery Aneurysm ................................................................................................................................... 647 Coronary Calcification .......................................................................................................................................... 650 Coronary Atherosclerotic Plaque .......................................................................................................................... 655 Coronary Thrombosis ........................................................................................................................................... 664 Coronary Artery Stenosis ...................................................................................................................................... 673 Ischemia RCA Stenosis .......................................................................................................................................... 681 Left Main Coronary Stenosis ................................................................................................................................. 687 3

Diagnostic Imaging Cardiovascular Coronary Artery Dissection ................................................................................................................................... 693 Acute Myocardial Infarction ................................................................................................................................. 699 Chronic Myocardial Infarction .............................................................................................................................. 705 Infarction LAD Distribution ................................................................................................................................... 711 Papillary Muscle Rupture...................................................................................................................................... 717 Right Ventricular Infarction .................................................................................................................................. 723 Nonatherosclerosis Myocardial Infarction ............................................................................................................ 729 Nontransmural Myocardial Infarction ................................................................................................................... 735 Post-Infarction LV Aneurysm ................................................................................................................................ 743 Post-Infarction LV Pseudoaneurysm ..................................................................................................................... 749 Post-Infarction Mitral Regurgitation ..................................................................................................................... 754 Left Ventricular Free Wall Rupture ....................................................................................................................... 757 Ventricular Septal Rupture ................................................................................................................................... 763 Post-Angioplasty Restenosis ................................................................................................................................. 766 In-Stent Restenosis............................................................................................................................................... 769 Post-CABG Thrombosis......................................................................................................................................... 777 Post-CABG Atherosclerosis ................................................................................................................................... 783 Myocardial Bridge ................................................................................................................................................ 789 Coronary Fistula ................................................................................................................................................... 792 Section 9 - Heart Failure ........................................................................................................................................... 797 Approach to Heart Failure .................................................................................................................................... 797 Right Heart Failure ............................................................................................................................................... 803 Left Heart Failure ................................................................................................................................................. 808 Heart Transplant .................................................................................................................................................. 814 Ventricular Assist Devices ..................................................................................................................................... 820 Left Ventricular Hypertrophy ................................................................................................................................ 827 Right Ventricular Hypertrophy .............................................................................................................................. 830 PVH/Pulmonary Edema (Cardiogenic) ................................................................................................................... 833 Cor Pulmonale...................................................................................................................................................... 842 Section 10 - Electrophysiology .................................................................................................................................. 845 Imaging Before and After Electrophysiology Procedures ....................................................................................... 845 Pulmonary Vein Mapping ..................................................................................................................................... 848 Pulmonary Vein Stenosis ...................................................................................................................................... 853 Pacemakers/ICDs ................................................................................................................................................. 859 Cardiac Vein Mapping .......................................................................................................................................... 865 Left Atrial Thrombus............................................................................................................................................. 868 Section 11 - Pulmonary Vasculature ......................................................................................................................... 873 Approach to Pulmonary Vasculature..................................................................................................................... 873 Pulmonary Arteriovenous Malformation .............................................................................................................. 878 Pulmonary Artery Pseudoaneurysm ..................................................................................................................... 881 Pulmonary Artery Aneurysm ................................................................................................................................ 884 Acute Pulmonary Embolism.................................................................................................................................. 890 Chronic Pulmonary Embolism ............................................................................................................................... 896 Pulmonary Sequestration ..................................................................................................................................... 902 Branch Pulmonary Artery Stenosis........................................................................................................................ 908 Pulmonary Arterial Hypertension ......................................................................................................................... 914 Pulmonary Venoocclusive Disease ........................................................................................................................ 921 Section 12 - Arterial ................................................................................................................................................. 924 Introduction and Overview ................................................................................................................................... 924 Approach to Congenital and Acquired Diseases of the Aorta ............................................................................. 924 Approach to Acute Aortic Syndrome ................................................................................................................. 927 Thoracic Aorta and Great Vessels ......................................................................................................................... 935 Thoracic Aorta and Great Vessel Anatomy ........................................................................................................ 935 Thoracic Aortic Aneurysm ................................................................................................................................. 946 Mycotic Aneurysm............................................................................................................................................ 955 Chronic Post-Traumatic Pseudoaneurysm ......................................................................................................... 961 Aortic Intramural Hematoma ............................................................................................................................ 967 Penetrating Atherosclerotic Ulcer ..................................................................................................................... 973 Aortic Dissection .............................................................................................................................................. 979 4

Diagnostic Imaging Cardiovascular Takayasu Arteritis ............................................................................................................................................. 988 Giant Cell Arteritis ............................................................................................................................................ 991 Marfan Syndrome............................................................................................................................................. 997 Pseudocoarctation.......................................................................................................................................... 1002 Traumatic Aortic Laceration ............................................................................................................................ 1008 Ductus Diverticulum ....................................................................................................................................... 1014 Abdominal Aorta and Visceral Vasculature ......................................................................................................... 1020 Abdominal Aorta and Visceral Vasculature Anatomy ....................................................................................... 1020 Abdominal Aortic Aneurysm ........................................................................................................................... 1027 AAA With Rupture .......................................................................................................................................... 1037 Aortic Graft Complications.............................................................................................................................. 1043 Abdominal Aortic Occlusion ............................................................................................................................ 1046 Section 13 - Venous ............................................................................................................................................... 1052 Approach to Venous Conditions ......................................................................................................................... 1052 Venous Anatomy................................................................................................................................................ 1054 Superior Vena Cava Syndrome............................................................................................................................ 1061 Inferior Vena Cava Anomalies ............................................................................................................................. 1068 Inferior Vena Cava Occlusion .............................................................................................................................. 1074 Left Superior Vena Cava ..................................................................................................................................... 1080 Azygos Continuation of the IVC........................................................................................................................... 1085 May-Thurner Syndrome ..................................................................................................................................... 1091 Nutcracker Syndrome......................................................................................................................................... 1097 Section 14 - Extracranial Cerebral Arteries .............................................................................................................. 1103 Approach to Extracranial Cerebral Arteries ......................................................................................................... 1103 Acute Ischemic Stroke ........................................................................................................................................ 1108 Atherosclerosis, Extracranial .............................................................................................................................. 1118 Carotid Stenosis, Extracranial ............................................................................................................................. 1124 Carotid Dissection .............................................................................................................................................. 1129 Carotid Pseudoaneurysm, Extracranial ............................................................................................................... 1135 Vertebral Dissection ........................................................................................................................................... 1140 Subclavian Steal Syndrome ................................................................................................................................. 1146 Section 15 - Renal Vasculature ............................................................................................................................... 1152 Approach to Renal Vasculature........................................................................................................................... 1152 Renal Vasculature Anatomy................................................................................................................................ 1160 Renal Artery Atherosclerosis .............................................................................................................................. 1164 Fibromuscular Dysplasia, Renal .......................................................................................................................... 1170 Polyarteritis Nodosa ........................................................................................................................................... 1176 Renal Arteriovenous Fistula ................................................................................................................................ 1182 Renal Vein Thrombosis ....................................................................................................................................... 1188 Section 16 - Peripheral Vasculature ........................................................................................................................ 1194 Introduction and Overview................................................................................................................................. 1194 Approach to Peripheral Vasculature................................................................................................................ 1194 Lower Extremity Vasculature Anatomy ........................................................................................................... 1196 Vasculature of the Trunk .................................................................................................................................... 1201 Subclavian Artery Stenosis/Occlusion ............................................................................................................. 1201 Subclavian Vein Thrombosis ........................................................................................................................... 1207 Iliac Artery Occlusive Disease .......................................................................................................................... 1213 Iliac Artery Aneurysmal Disease ...................................................................................................................... 1220 Lower Extremity Vasculature .............................................................................................................................. 1226 Lower Extremity Aneurysms ........................................................................................................................... 1226 Acute Lower Extremity Ischemia ..................................................................................................................... 1232 Femoropopliteal Artery Occlusive Disease ...................................................................................................... 1238 Cystic Adventitial Disease ............................................................................................................................... 1244 Persistent Sciatic Artery .................................................................................................................................. 1250 Arteriovenous Fistula...................................................................................................................................... 1253 Deep Vein Thrombosis.................................................................................................................................... 1259 Index ..................................................................................................................................................................... 1266

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Diagnostic Imaging Cardiovascular

Editors Editors Suhny Abbara MD, FSCCT Professor of Radiology Chief, Division of Cardiac and Thoracic Imaging Director, 3D Image Processing Laboratory University of Texas Southwestern Medical Center Dallas, Texas Authors Stephan Achenbach, MD Chairman Department of Cardiology University of Erlangen Erlangen, Germany Brett W. Carter, MD Assistant Professor of Radiology The University of Texas MD Anderson Cancer Center Houston, Texas Christopher M. Walker, MD Assistant Professor of Radiology Saint Luke's Hospital of Kansas City University of Missouri-Kansas City Kansas City, Missouri Jonathan D. Dodd, MD, MSc, MRCPI, FFR(RCSI) Associate Professor of Radiology University College Dublin Director of Radiology St. Vincent's University Hospital Dublin, Ireland Raymond J. Kim, MD Director, Duke Cardiovascular Magnetic Resonance Center Professor of Medicine and Radiology Duke University Medical Center Durham, North Carolina T. Gregory Walker, MD, FSIR Assistant Professor of Radiology Harvard Medical School Associate Director, Fellowship Division of Interventional Radiology Massachusetts General Hospital Boston, Massachusetts Jonathan Hero Chung, MD Associate Professor, Department of Radiology Director of Radiology Professional Quality Assurance Director of Cardiopulmonary Imaging Fellowship National Jewish Health Denver, Colorado John D. Grizzard, MD Associate Professor of Radiology Section Chief, Non-Invasive Cardiovascular Imaging VCU Health Systems Richmond, Virginia Sanjeeva P. Kalva, MBBS, MD, FSIR Associate Professor of Radiology Chief, Division of Interventional Radiology University of Texas Southwestern Medical Center Dallas, Texas 6

Diagnostic Imaging Cardiovascular Santiago Martínez-Jiménez, MD Associate Professor of Radiology University of Missouri-Kansas City Saint Luke's Hospital of Kansas City Kansas City, Missouri Carol C. Wu, MD Instructor of Radiology Harvard Medical School Assistant Radiologist Massachusetts General Hospital Boston, Massachusetts John P. Lichtenberger, III, MD Chief of Cardiothoracic Imaging David Grant Medical Center Travis Air Force Base, California Assistant Professor of Radiology Uniformed Services University of the Health Sciences Bethesda, Maryland Sanjeev A. Francis, MD Director, Cardio-Oncology Program Cardiac MRI/CT Program Instructor in Medicine Harvard Medical School Massachusetts General Hospital Boston, Massachusetts Suvranu “Shoey” Ganguli, MD Assistant Professor of Radiology Harvard Medical School Vascular & Interventional Radiology Massachusetts General Hospital Boston, Massachusetts P.vi

Contributing Authors Bronwyn E. Hamilton, MD Associate Professor of Radiology Associate Director of Neuroradiology Fellowship Neuroradiology Division Oregon Health & Science University Portland, Oregon Carlos A. Rojas, MD Assistant Professor of Radiology University of South Florida Associate Director Cardiothoracic Imaging Fellowship Tampa, Florida C. Douglas Phillips, MD, FACR Professor of Radiology Director of Head and Neck Imaging Weill Cornell Medical College NewYork-Presbyterian Hospital New York, New York Daniel W. Entrikin, MD Associate Professor Departments of Radiology and Internal Medicine Section on Cardiology Wake Forest University School of Medicine Winston-Salem, North Carolina 7

Diagnostic Imaging Cardiovascular Gudrun Feuchtner, MD Associate Professor of Radiology Innsbruck Medical University Innsbruck, Austria Gerald F. Abbott, MD Associate Professor of Radiology Harvard Medical School Massachusetts General Hospital Boston, Massachusetts Darragh Brady, MD, MRCPI Research Fellow University College Dublin Dublin, Ireland Lowie M.R. Van Assche, MD Post Doctoral Research Fellow Duke Cardiovascular Magnetic Resonance Center Duke University Medical Center Durham, North Carolina Kathryn M. Olsen, MD Assistant Professor of Radiology Virginia Commonwealth University School of Medicine VCU Medical Center Richmond, Virginia Michael T. Lu, MD Fellow, Cardiac and Thoracic Imaging Harvard Medical School Massachusetts General Hospital Boston, Massachusetts Naveen M. Kulkarni, MD Fellow, Cardiac and Thoracic Imaging Harvard Medical School Massachusetts General Hospital Boston, Massachusetts P.vii

Roy Bryan, MD, MBA Clinical Fellow, Radiology Harvard Medical School Massachusetts General Hospital Boston, Massachusetts Andrew J. Gunn, MD Clinical Fellow, Radiology Harvard Medical School Massachusetts General Hospital Boston, Massachusetts Cameron Hassani, MD Assistant Professor of Radiology Keck Medical Center of USC University of Southern California Los Angeles, California Rahul Sheth, MD Fellow, Division of Abdominal Imaging and Interventions Department of Radiology Harvard Medical School Massachusetts General Hospital Boston, Massachusetts Ali Devrim Karaosmanoglu, MD

8

Diagnostic Imaging Cardiovascular Clinical Fellow, Cardiac Imaging Department of Radiology Harvard Medical School Massachusetts General Hospital Boston, Massachusetts Terrance T. Healey, MD Director, Thoracic Radiology Assistant Professor of Diagnostic Imaging Department of Diagnostic Imaging Warren Alpert Medical School of Brown University Providence, Rhode Island Jeffrey P. Kanne, MD Associate Professor Chief of Thoracic Imaging Vice Chair of Quality and Safety Department of Radiology University of Wisconsin School of Medicine and Public Health Madison, Wisconsin Melissa L. Rosado-de-Christenson, MD, FACR Section Chief, Thoracic Imaging Saint Luke's Hospital of Kansas City Professor of Radiology University of Missouri-Kansas City Kansas City, Missouri Rebecca S. Cornelius, MD, FACR Professor of Radiology and Otolaryngology— Head and Neck Surgery University of Cincinnati College of Medicine University of Cincinnati Medical Center Cincinnati, Ohio Tyler H. Ternes, MD Chest Imaging Fellow Saint Luke's Hospital of Kansas City University of Missouri-Kansas City Kansas City, Missouri

Dedication Dedication To Amanda, Tyler, Marlene, Yasser, Mona, and Susu. SA

Foreword Cardiovascular imaging continues to evolve. Cardiac computed tomography and cardiac magnetic resonance imaging are widely available and have expanded appropriate use, flexibility and popularity. Traditional imaging modalities such as echocardiography, nuclear cardiology and digital fluoroscopy are also morphing into new technologies, with new applications including preoperative planning of transcatheter valve replacement and transcutaneous treatment of many congenital diseases. Radiologists are challenged today to embrace the complexity of cardiovascular pathologic anatomy and physiology as never before. Conversely, cardiologists have had to reorient their thinking and expand their knowledge to include the entire range of thoracic anatomy and pathology, rather than restrict their attention to the heart alone. For the patient, this more holistic viewpoint can only be beneficial. For the physician, embracing the breadth of our responsibilities can be intimidating, particularly at advanced imaging facilities that receive referrals of the most difficult and unusual cases. As a cardiologist who directs a combined radiology/cardiology advanced cardiovascular imaging teaching program, I found the first edition of Diagnostic Imaging: Cardiovascular to be a uniquely successful resource, both for physiciansin-training and for our attending physicians, due to its lucid organization, fine illustrations, extensive clinical images, and the uniform excellence of its text. The organization and presentation of the material is successful because it is so clear. This derives from the talents of the authors, the publisher, and the artists, who collaborate to present a visually appealing and highly readable style. 9

Diagnostic Imaging Cardiovascular Separate boxes on terminology, imaging findings, differential diagnosis, pathology, and clinical issues all complement the image gallery for each disease entity. The authors go beyond traditional didactic texts by integrating clinical features, alternative diagnoses, and potential diagnostic pitfalls. The result concisely summarizes a vast amount of diagnostic expertise with a clarity that is hard to duplicate. The second edition has incorporated entirely new clinical images, which is a major undertaking but vitally important in such a rapidly changing field. There are expanded sections on diagnostic anatomy, additional material on imaging technique and introductory text on the role of imaging in clinical management. In summary, Diagnostic Imaging: Cardiovascular is a key textbook for our clinical cardiovascular imaging practice and teaching service, with radiologists, cardiologists, residents, and fellows working collaboratively in a high-volume environment. It is an outstanding book and highly recommended. Gilbert L. Raff, MD Director, Advanced Cardiovascular Imaging Florine and J. Peter Ministrelli Endowed Chair in Cardiovascular Research Oakland University William Beaumont School of Medicine Rochester, Michigan

Preface Since the publication of the first edition of Diagnostic Imaging: Cardiovascular, there have been a number of significant advancements in the field of cardiovascular medicine. New treatments have become available, imaging methods have further developed, the published scientific evidence related to cardiovascular imaging has doubled. As a result, new complex guidelines on the management of patients with cardiovascular disorders have been published. The role of cardiovascular imaging is at the heart of many of these guidelines, illuminating the evolution of imaging and its critical role in patient management. In this second edition of Diagnostic Imaging: Cardiovascular, we were fortunate to attract some of the top world experts in cardiac CT and MR as well as several rising stars in the fields of cardiac and vascular imaging, both from radiology and cardiology backgrounds. I am immensely grateful to the many authors who have made this work possible. Several aspects of this edition are new. First, the imaging content is nearly 100% new. Virtually every figure has been replaced with one or several new, high-quality illustrative figures, 2,473 in total. More than 1,000 additional figures from the first edition are made accessible to the reader in the eBook version of this work. The illustrations have been updated, and new tables have been added where useful. Additionally, there are 18 new section introductions that review the “how to” technical aspects of cardiac MR and CT imaging as well as introductions that review the approach to patients with a suspected type of pathology. Eight new detailed anatomy modules with several drawings and illustrative imaging studies have been created. In total, this edition has 203 chapters, of which 32 are new and 171 have been extensively revised and updated from the first edition. Creating this text has been an incredible effort for a large group of wonderful people. I am very grateful for the tremendous support and encouragement from the publishing and art and design teams at Amirsys as well as the senior leadership at Amirsys. The exquisite creative talents of all the authors and the contributions of their associates, trainees, and their patients have made this work possible, and I am most grateful for that. I truly hope you will find this second edition of Diagnostic Imaging: Cardiovascular informative, enjoyable, and useful in everyday practice. Suhny Abbara, MD, FSCCT Professor of Radiology Chief, Division of Cardiac and Thoracic Imaging Director, 3D Image Processing Laboratory University of Texas Southwestern Medical Center Dallas, Texas

Acknowledgments Text Editing Dave L. Chance, MA, ELS Arthur G. Gelsinger, MA Lorna Kennington, MS Rebecca L. Hutchinson, BA Angela M. G. Terry, BA Sarah J. Connor, BA 10

Diagnostic Imaging Cardiovascular Image Editing Jeffrey J. Marmorstone, BS Lisa A. M. Steadman, BS Medical Editing Bobak Heydari, MD, MPH Umesh C. Sharma, MD Illustrations Richard Coombs, MS Laura C. Sesto, MA Lane R. Bennion, MS Art Direction and Design Laura C. Sesto, MA Lisa A. M. Steadman, BS Lead Editor Kalina K. Lowery, MS Production Lead Katherine Riser, MA

Section 1 - Introduction and Overview Cardiac CT: Acquisition and Postprocessing Indications and Interpretation > Table of Contents > Section 1 - Introduction and Overview > Cardiac CT: Acquisition and Postprocessing Indications and Interpretation Cardiac CT: Acquisition and Postprocessing Indications and Interpretation Stephan Achenbach, MD Introduction Due to the rapid technical evolution of computed tomography (CT), cardiac imaging has become reliably possible, and CT has assumed a new clinical role for the work-up of cardiac disease. Noninvasive coronary CT angiography in particular has tremendous clinical potential for detecting or ruling out coronary artery stenoses in some patients. Imaging of cardiac structure and function, potentially even perfusion, can be useful in selected patients. However, the spatial resolution, and especially the temporal resolution of CT imaging, even in the latest scanner generations, still possesses certain restrictions and can lead to artifacts and imaging limitations that must be taken into account during data acquisition and interpretation. Diagnostic accuracy is impaired when image quality is reduced. In turn, image quality is influenced by many factors, such as the patient's heart rate, body weight, ability to cooperate, and, for coronary CT angiography, the extent of coronary calcification. Therefore, the clinical utility of cardiac CT significantly depends both on the specific clinical situation and on the patient under investigation. The specific advantages and disadvantages of cardiac CT and coronary CT angiography must be carefully considered before using either method in the work-up of a patient with known or suspected coronary artery disease or other cardiovascular disorders. Imaging Protocol Currently, 64-slice CT imaging is considered a state-of-the-art modality for coronary artery studies. Newer technologies, such as dual-source CT and scanners that allow simultaneous acquisition of 256 or 320 cross sections, provide further improved image quality and are less susceptible to artifacts. Patient Preparation Even slight respiratory motion during data acquisition will cause substantial artifact on cardiac CT. Therefore, patients must be able to follow breath-hold commands and hold their breath for approximately ten seconds. For most imaging purposes, heart rate should be regular, and if coronary CT angiography is attempted, heart rate should be < 65 beats/min and, optimally, < 60 beats/min. Patients therefore usually receive pre-procedure medication with shortacting β-blockers that can be administered orally approximately one hour prior to scanning or intravenously immediately before the scan. In order to achieve coronary dilatation on CT angiography and thus substantially improve image quality, nitrates should be given to all patients who have no contraindications. Contrast Injection For contrast-enhanced imaging of the heart, 50-100 mL of iodine-based high-concentration contrast agent is injected intravenously. Recommended flow rates are 4-7 mL/s, and the contrast bolus should be followed by saline solution or a mixture of saline and contrast to improve right heart visualization. Synchronization of contrast injection and data 11

Diagnostic Imaging Cardiovascular acquisition can be achieved either through a bolus tracking method or by using a separate “test bolus” acquisition. For visualization of the coronary veins, the delay between contrast injection and the start of image acquisition must be prolonged by about six to ten seconds. Data Acquisition Subsequent data acquisition can follow various principles. Reconstructed images need to be synchronized with the heart beat, and this can be achieved through either retrospective ECG gating or prospective ECG triggering. Retrospectively gated scans are acquired in spiral mode and usually provide for high image quality, flexibility to choose the cardiac phase during which images are reconstructed, as well as ability to reconstruct functional data sets throughout the cardiac cycle in order to analyze cardiac function. To limit radiation exposure, the output of the x-ray tube can be modulated during the acquisition, with lower output in systole and higher output in diastole. The most relevant image reconstructions are usually performed in diastole. Prospectively triggered scans are associated with substantially lower radiation exposure. Less flexibility to reconstruct data at different time instants is the trade-off for the advantage of lower dose. Heart rate must be low so that artifactfree images can be guaranteed at the time instant of radiation exposure. Image Reconstruction and Postprocessing Typical data sets for coronary artery visualization by CT consist of approximately 200-300 thin (0.5-0.75 mm) transaxial cross sections. Useful postprocessing tools include maximum-intensity projections and multiplanar reconstructions. 3D renderings may be impressive but are not accurate for stenosis detection and play no role in data interpretation. Coronary CT Angiography Most cardiac CT investigations are performed to detect or rule out significant coronary artery stenosis. On CT, stenosis severity can appear to be less or more than seen on invasive angiography; the typical limits of agreement are approximately ± 20%. Thus, stenoses that appear to be < 50% on CT can be assumed to be < 70% on invasive angiography with a very high degree of certainty. In most cases, however, there is a tendency to overestimate, rather than underestimate, the degree of luminal stenosis on coronary CT angiography as compared with catheter-based invasive coronary angiography. False-positive findings are frequent when image quality is reduced. Insufficient image quality is most frequently the consequence of motion artifact (secondary to either coronary movement or, less often, respiration), high image noise, or a combination of both. Severe calcification can cause additional problems. In some cases, artifacts render some coronary segments, or even the entire data set, unevaluable. This has become less frequent with modern scanners but can still occur, especially if patients are not adequately prepared or data acquisition is not carefully performed. Coronary CT angiography has a high sensitivity and a very high negative predictive value for the identification of coronary stenosis. Severe coronary lesions are very infrequently missed, and CT angiography is extremely reliable to rule out coronary artery stenosis. Specificity and positive predictive value may be lower because of the tendency to overestimate stenosis because of artifacts and because coronary artery stenosis, even if detected with high image quality, does not always lead to myocardial ischemia. P.1:3

The very high negative predictive value makes coronary CT angiography an especially clinically useful tool in symptomatic patients who have a lower or intermediate likelihood of coronary disease but require further work-up to rule out significant coronary stenoses. This applies both to patients with stable chest pain and to patients with acute chest pain and a suspected acute coronary syndrome. A negative coronary CT angiography scan will render further testing unnecessary. Indeed, several observational trials have clearly demonstrated that when coronary CT angiography was negative, symptomatic patients had a very favorable clinical outcome even without further additional testing and that downstream healthcare costs may be lower than with other diagnostic procedures. Coronary CT Angiography and Ischemia Coronary CT angiography, like invasive angiography, is a purely morphologic imaging modality and cannot demonstrate the functional relevance of stenoses (i.e., ischemia). Especially in the case of lesions with a borderline degree of stenosis, poor correlation of CT findings with myocardial ischemia may limit the clinical application of CT angiography. Several methods are under evaluation to improve the ability of coronary CT angiography to predict ischemia. They include the combination with CT-based myocardial perfusion and specific analysis methods, such as CT-based determination of the fractional flow reserve. Based on the anatomic CT data set, computational fluid dynamics are applied to model the flow and resistance pattern under adenosine stress and to obtain the fractional flow reserve value for all segments of the coronary artery tree. Publications of initial studies show that this is feasible and has potential to improve the specificity of CT to identify ischemia causing lesions over a purely anatomic assessment alone. However, further validation is necessary. Coronary CT angiography, like invasive angiography, should not be performed in an unselected patient population or for “screening” purposes. A positive CT scan taken by itself does not strongly predict the need for revascularization. 12

Diagnostic Imaging Cardiovascular However, a negative coronary CT angiography result is extremely reliable to rule out the presence of coronary artery stenoses and the need for revascularization. Imaging of Patients With Bypass Grafts and Stents Coronary CT angiography has relevant limitations in patients with previous coronary revascularization. In patients who have undergone bypass surgery, the accuracy of the detection of graft stenosis and occlusion is extremely high. However, assessing the native coronary arteries can be extremely difficult because of their often small diameter and severe calcification. Consequently, the accuracy of detecting and ruling out stenoses in nongrafted and runoff vessels is substantially lower. Imaging of Coronary Atherosclerotic Plaque Coronary Calcification Using cardiac CT, calcium in the coronary arteries can be detected and quantified in low-radiation, nonenhanced image acquisition protocols. Tissue within the vessel wall with a CT number of ≥ 130 Hounsfield units is defined as calcified. For qualification, the Agatston score, which takes into account the area and the CT density of calcified lesions, is used. Coronary calcifications, with the possible exception of calcifications in patients with renal failure, are always due to coronary atherosclerotic plaque. The correlation between calcium and stenosis is poor. The lack of calcium therefore does not reliably eliminate the possibility of coronary artery stenosis in symptomatic individuals. On the other hand, even substantial amounts of coronary calcium are not necessarily associated with the presence of hemodynamically relevant luminal narrowing. Therefore, the detection of coronary calcium alone, even when very pronounced, should not prompt invasive coronary angiography in otherwise asymptomatic individuals. Coronary calcium is associated with individual coronary artery disease risk. In asymptomatic individuals, the absence of coronary calcium is associated with very low (< 1% per year) risk of major cardiovascular events over the next three to five years. Note, however, that a significantly increased risk of major cardiac events has been reported in asymptomatic subjects with extensive coronary calcification in numerous trials. For risk stratification, coronary calcium is superior to other measures of risk, such as C-reactive protein or intimamedia thickness tests. A potential clinical role of coronary calcium for further risk stratification is assumed for patients who have an intermediate risk as assessed by traditional risk factors. Coronary calcium imaging therefore can be used when a decision regarding risk-modifying treatment, such as statin therapy, hinges on additional information beyond conventional risk factor analysis. Unselected screening or patient self-referral is not recommended. Plaque in Coronary CT Angiography Coronary CT angiography allows visualization of nonstenotic coronary atherosclerotic plaque if image quality is good. With some limitations, and again under the prerequisite of excellent image quality, plaque quantification and characterization are possible. Some parameters that are readily available from CT might contribute to the detection of vulnerable plaques at an increased risk for near-term rupture. Several studies and data based on large registries have demonstrated a prognostic value of atherosclerotic lesions detected by coronary CT angiography both in symptomatic and asymptomatic individuals. An analysis of a clinical registry including > 23,000 patients confirmed the prognostic value of coronary CT angiography in cases where the presence of coronary stenoses and the presence of nonobstructive plaque were associated with an increased risk of mortality. However, the hazard ratio for nonobstructive plaque was relatively low (i.e., hazard ratio of 1.6 with 95% confidence interval of 1.2-2.2). Furthermore, another analysis of the same registry was unable to demonstrate, for this mostly symptomatic patient group, an incremental prognostic value of contrast-enhanced coronary CT angiography over coronary calcium measurements. Therefore, coronary CT angiography for the identification of coronary atherosclerotic plaque is currently not recommended for risk assessment purposes in asymptomatic individuals. P.1:4

Noncoronary Cardiac CT Cardiac CT permits high-resolution functional and morphologic imaging of the heart. Although cardiac CT is most frequently utilized for coronary artery imaging, it can also be useful for other applications. Cardiac CT is highly accurate in assessing left and right ventricular function. Even parameters of diastolic dysfunction can be derived from CT. Clinically, however, it will only be used if echocardiography and magnetic resonance imaging fail. Morphologic imaging of the heart has applications in congenital heart disease and in the follow-up of cardiac surgery. Again, however, CT will typically be used only when echocardiography and magnetic resonance imaging are unable to yield the desired results. Cardiac CT can be used to assess left-sided cardiac valves (adequate contrast enhancement is often a problem for imaging of right-sided cardiac valves). It has been shown that both the degree of stenosis and the degree of regurgitation can be estimated by CT.

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Diagnostic Imaging Cardiovascular Another application of major importance is the use of CT imaging in the evaluation of patients who are candidates for transcatheter aortic valve replacement. CT imaging permits assessment of the femoral and iliac access vessels, and CT angiography provides detailed measurement of aortic annulus dimensions. In fact, it has been shown that procedure success is increased and complication rates are reduced when CT imaging is incorporated into the pre-transcatheter aortic valve replacement work-up for prosthesis size selection and identification of suitable candidates. Selected References 1. Taylor CA et al: Computational fluid dynamics applied to cardiac computed tomography for noninvasive quantification of fractional flow reserve: scientific basis. J Am Coll Cardiol. 61(22):2233-41, 2013 2. Achenbach S et al: SCCT expert consensus document on computed tomography imaging before transcatheter aortic valve implantation (TAVI)/transcatheter aortic valve replacement (TAVR). J Cardiovasc Comput Tomogr. 6(6):366-80, 2012 3. Hoffmann U et al: Coronary CT angiography versus standard evaluation in acute chest pain. N Engl J Med. 367(4):299-308, 2012 4. Litt HI et al: CT angiography for safe discharge of patients with possible acute coronary syndromes. N Engl J Med. 366(15):1393-403, 2012 5. Min JK et al: Age- and sex-related differences in all-cause mortality risk based on coronary computed tomography angiography findings results from the International Multicenter CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry) of 23,854 patients without known coronary artery disease. J Am Coll Cardiol. 58(8):849-60, 2011 6. Erbel R et al: Coronary risk stratification, discrimination, and reclassification improvement based on quantification of subclinical coronary atherosclerosis: the Heinz Nixdorf Recall study. J Am Coll Cardiol. 56(17):1397-406, 2010 7. Min JK et al: The present state of coronary computed tomography angiography a process in evolution. J Am Coll Cardiol. 55(10):957-65, 2010 8. Pflederer T et al: Aortic valve stenosis: CT contributions to diagnosis and therapy. J Cardiovasc Comput Tomogr. 4(6):355-64, 2010 9. Taylor AJ et al: ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 appropriate use criteria for cardiac computed tomography. A report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. J Am Coll Cardiol. 56(22):1864-94, 2010 10. Abbara S et al: SCCT guidelines for performance of coronary computed tomographic angiography: a report of the Society of Cardiovascular Computed Tomography Guidelines Committee. J Cardiovasc Comput Tomogr. 3(3):190-204, 2009 11. Motoyama S et al: Computed tomographic angiography characteristics of atherosclerotic plaques subsequently resulting in acute coronary syndrome. J Am Coll Cardiol. 54(1):49-57, 2009 12. Raff GL et al: SCCT guidelines for the interpretation and reporting of coronary computed tomographic angiography. J Cardiovasc Comput Tomogr. 3(2):122-36, 2009 13. Sayyed SH et al: Use of multidetector computed tomography for evaluation of global and regional left ventricular function. J Cardiovasc Comput Tomogr. 3(1 Suppl):S23-34, 2009 14. Budoff MJ et al: Diagnostic performance of 64-multidetector row coronary computed tomographic angiography for evaluation of coronary artery stenosis in individuals without known coronary artery disease: results from the prospective multicenter ACCURACY (Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography) trial. J Am Coll Cardiol. 52(21):1724-32, 2008 15. Detrano R et al: Coronary calcium as a predictor of coronary events in four racial or ethnic groups. N Engl J Med. 358(13):1336-45, 2008 16. Meijboom WB et al: Diagnostic accuracy of 64-slice computed tomography coronary angiography: a prospective, multicenter, multivendor study. J Am Coll Cardiol. 52(25):2135-44, 2008 17. Miller JM et al: Diagnostic performance of coronary angiography by 64-row CT. N Engl J Med. 359(22):2324-36, 2008 18. Ferencik M et al: Diagnostic accuracy of image postprocessing methods for the detection of coronary artery stenoses by using multidetector CT. Radiology. 243(3):696-702, 2007 19. Meijboom WB et al: 64-slice computed tomography coronary angiography in patients with high, intermediate, or low pretest probability of significant coronary artery disease. J Am Coll Cardiol. 50(15):1469-75, 2007 20. McClelland RL et al: Distribution of coronary artery calcium by race, gender, and age: results from the Multi-Ethnic Study of Atherosclerosis (MESA). Circulation. 113(1):30-7, 2006 P.1:5

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Diagnostic Imaging Cardiovascular Image Gallery

(Left) Axial cardiac CTA, 5 mm maximum-intensity projection at the level of the left main coronary artery, shows proximal segments of the left anterior descending coronary artery and left circumflex coronary artery . (Right) Axial cardiac CTA maximum-intensity projection image, several millimeters more caudally, shows cross sections of the left anterior descending coronary artery , the diagonal branch , and the left circumflex coronary artery .

(Left) Axial cardiac CTA thin maximum-intensity projection image at the level of the right coronary ostium shows the proximal right coronary artery . Cross sections of the left anterior descending artery, the diagonal branch , and the left circumflex artery end branches are also seen. (Right) Axial cardiac CTA image at the level of the mid right coronary artery shows the right coronary artery in cross section. The end branches of the left anterior descending and left circumflex arteries are also shown.

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Diagnostic Imaging Cardiovascular

(Left) Axial coronary CT maximum-intensity projection image (7 mm thickness) shows the distal right coronary artery , the posterior descending artery , and an acute marginal branch . (Right) Cardiac CT curved multiplanar reconstruction shows the entire course of the right coronary artery . P.1:6

(Left) Invasive coronary angiography shows a high-grade stenosis of the distal left anterior descending coronary artery after the 2nd diagonal branch. (Right) Coronary CT angiography maximum-intensity projection (7 mm thickness) in a curved plane in the same patient shows a corresponding stenosis of the left anterior descending coronary artery. Note absence of calcium at the stenosis site.

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Diagnostic Imaging Cardiovascular

(Left) High-threshold 3D reconstruction in the same patient shows the stenosis . The value of 3D reconstructions for stenosis assessment is extremely limited because the visualization of stenoses depends strongly on manually chosen window and level settings. (Right) As this 3D reconstruction image shows, the stenosis is not detectable with a lower threshold.

(Left) This typical visualization of coronary artery stenoses in a coronary CT angiography maximum-intensity projection (7 mm thickness) of the proximal left anterior descending coronary artery demonstrates a stenosis in the mid left anterior descending coronary artery segment . (Right) Invasive coronary angiogram in the same patient can be used to confirm the stenosis initially detected in cardiac CTA. P.1:7

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Diagnostic Imaging Cardiovascular

(Left) Bypass graft stenosis in coronary CT angiography, curved multiplanar reconstruction, shows a venous bypass graft to the left anterior descending coronary artery with a high-grade stenosis . The inset shows invasive coronary angiography. (Right) 3D model shows simulated fractional flow reserve within the coronary tree. The color coding represents fractional flow reserve values for the respective coronary artery branch.

(Left) Nonenhanced CT demonstrates coronary calcifications of the proximal left anterior descending coronary artery. (Right) Contrast-enhanced CT shows noncalcified plaque components. Here, a partially calcified plaque without significant luminal stenosis in the proximal left anterior descending coronary artery is present. The inset shows a cross-sectional view of the lesion.

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Diagnostic Imaging Cardiovascular

(Left) Functional imaging via contrast-enhanced CT shows (top) left ventricular function with a regional wall motion abnormality in systole and (bottom) normal function of the aortic valve. (Right) Aortic annulus is shown before (left) and after (right) transcatheter aortic valve replacement . Note the oval shape prior to transcatheter aortic valve replacement, which becomes round after a valve prosthesis has been placed.

Cardiac MR: Acquisition and Imaging Protocols Introduction Over the last several years, cardiovascular magnetic resonance (CMR) imaging has undergone rapid evolution, and tremendous advances in pulse sequence design, scanner hardware, and coil technology have resulted in progressive expansion of the clinical applications. In particular, new pulse sequences such as the late gadolinium enhancement (LGE) technique have leveraged the inherently superior soft tissue contrast provided by MR to enable superb in vivo viability imaging. These improvements have led to the recognition of CMR as the reference standard for the assessment of regional and global systolic function, the detection of myocardial infarction and viability, and the evaluation of pericardial disease and cardiac masses. This chapter provides a brief overview of the common techniques used in CMR. Suggested protocols for imaging common disorders will be presented in a tabular format at the end of this section. CMR Techniques A unique characteristic of MR imaging is that a variety of information can be obtained simply by selecting different software sequences to probe the tissue characteristics of the organ in question. Morphologic Images: Dark Blood Imaging Morphologic black blood imaging is performed with single-shot double inversion-recovery fast spin-echo (IR-FSE) and half-Fourier acquisition single-shot turbo spin-echo (HASTE) techniques. These result in still-frame images and are acquired in the standard orthogonal imaging planes (i.e., axial, sagittal, or coronal). The repetition time is typically set at 90% of the R-R interval and adjusted to null the signal from blood. The rapidity of acquisition is such that breath holding is not required. These resulting images produce an excellent depiction of the overall myocardial structure and the relationships of the great vessels. Occasionally, segmented FSE images are acquired when higher spatial resolution &/or improved T1 or T2 weighting is desired, such as when characterizing cardiac masses. These acquisitions take approximately 7-10 seconds per image and require breath holding. They can be performed either with or without fat saturation. T2-weighted images are helpful in demonstrating an edema, a finding useful in determining if an infarct is acute or chronic, and in diagnosing myocarditis. Some evidence suggests that T2-weighted imaging may allow the depiction of the area at risk (but not infarcted) from an acute ischemic injury, but the evidence is controversial. T2* imaging using a multiecho gradient recall echo (GRE) sequence has proven to be an extremely accurate and useful technique for quantifying cardiac iron deposition and is now considered the reference standard for monitoring and managing cardiac iron overload syndromes (including thalassemia). Morphologic Images: Bright Blood Imaging The steady-state free precession (SSFP) sequence is now the standard sequence for bright blood imaging. With this sequence, image contrast is not dependent on inflow effects (as with the older GRE sequences) but rather on the T2/T1 ratio of the tissue being imaged. The result is a bright signal for intracavitary blood and a relatively dark appearance for myocardium. Images can be rapidly acquired (typically in < 300-400 milliseconds per image). These 19

Diagnostic Imaging Cardiovascular sequences do not require breath holding and are also a form of single-shot imaging. One image is typically acquired during each heartbeat (at the same cardiac phase), and a stack of 30 images can be acquired in approximately 30 seconds. SSFP sequences are very useful in the evaluation of disorders producing intraluminal abnormalities (such as aortic dissection). Cine Imaging The SSFP technique can be adapted for cine acquisition in which multiple images are obtained at a single-slice location in rapid succession during different phases of the cardiac cycle and can be displayed as a continuous movie loop. Typically, 20-30 frames per cycle are reconstructed. Cine imaging allows evaluation of ventricular wall motion abnormalities, assessment of dynamic changes in wall thickness, and measurement of chamber sizes. The standard cine sequence is a segmented, retrospectively gated acquisition in which the data are acquired throughout the cardiac cycle and “time stamped” to allow assignment to the proper cardiac phase. The 6-8 mm slices are acquired at 1 cm intervals in the short-axis plane from the mitral valve to the apex, and standard long-axis views (2-, 3-, and 4-chamber views) are also obtained. A matrix of 256 × 200 is typically used, with a resultant spatial resolution of 1-1.6 mm, and with a temporal resolution of < 45 milliseconds. The segmented acquisition indicates that data from several heartbeats are combined to yield the image. Hence, irregularities in the patient's heart rate and rhythm may degrade image quality. In cases of arrhythmia, prospectively triggered acquisitions may be helpful. In this technique, images are acquired beginning with the R wave and for a predetermined length of time (usually up to early or mid diastole). This can remove some of the artifacts that result from irregular cycle lengths, as changes in heart rate predominately affect the length of diastole rather than systole. Unfortunately, prospectively triggered acquisitions often result in the loss of the terminal phase of diastole, and measurements of ventricular ejection fraction and chamber volumes from these acquisitions may be slightly imprecise. If gating is unsuccessful, the arrhythmia is severe, or the patient cannot breathhold adequately, real-time cine acquisitions may be necessary. These acquisitions also employ SSFP sequences in a single-shot rather than segmented fashion. Although these acquisitions have lower spatial and temporal resolution, they may provide sufficient information for diagnosis. In addition, real-time cine acquisitions can be helpful in the detection of dynamic processes because they can be acquired during inspiratory and expiratory maneuvers. Perfusion Imaging Perfusion imaging sequences are designed to demonstrate contrast media passage through the myocardium in a manner that reliably reflects myocardial blood flow. It is desirable to have multiple slices during each heartbeat to ensure sufficient ventricular coverage with high temporal resolution. The sequences used by various manufacturers differ, but the general strategy is to acquire heavily T1-weighted images of the myocardium and to accurately depict the passage of a T1-shortening contrast agent such as gadolinium. Perfusion imaging is most often used for the detection of obstructive coronary artery disease, where P.1:9 it is performed with pharmacological vasodilation (e.g., adenosine or regadenoson). During adenosine infusion, myocardial blood flow increases approximately fourfold downstream of normal coronary arteries but does not normally increase downstream of severely diseased arteries, because the arteriolar beds are already maximally vasodilated. MR perfusion imaging is a first-pass imaging study that directly images the passage of contrast; therefore, it is performed using an abbreviated adenosine protocol (approximately 3 minutes). MR perfusion imaging has higher spatial resolution than nuclear techniques; thus, it can depict small subendocardial perfusion defects that may be inapparent on nuclear techniques. Although research studies often emphasize complex postprocessing of the perfusion data, recent reports using visual analysis demonstrate comparable sensitivity and specificity. Perfusion imaging can also be used in the evaluation of suspected intracardiac shunts as well as in the characterization of cardiac masses. Viability Imaging (LGE Imaging) Normal, infarcted, and scarred myocardia will all demonstrate contrast enhancement. However, they have different contrast kinetics in that contrast will wash out of normal myocardium at a much more rapid rate than it will from infarcted or scarred myocardium. In addition, areas of infarction, whether acute or chronic, will have a larger amount of extracellular space and a greater volume of distribution for gadolinium contrast than will normal myocardium. Accordingly, areas of prior infarction will have higher concentrations of contrast on delayed images (5-10 minutes after intravenous administration). The LGE sequences used for infarct detection are designed to maximize the differential signal intensity between normal myocardium and infarcted myocardium. The standard LGE imaging sequence incorporates a segmented GRE read-out and an inversion prepulse to produce heavy T1 weighting. The inversion pulse serves to flip the magnetization 180 degrees. The recovery of magnetization back to baseline in areas that have a higher gadolinium concentration will be more rapid (as they have a lower T1 value) than in those with a lower concentration of gadolinium, such as normal myocardium. Therefore, the increased concentration of gadolinium in an area of scar will be reflected by more rapid return above the zero-crossing line and back to baseline longitudinal magnetization. The time after the inversion pulse at which normal myocardium is at the 20

Diagnostic Imaging Cardiovascular zero-crossing line will result in maximum suppression of signal from a normal myocardium (the myocardium is said to be “nulled”) and will result in maximum conspicuity of the area of infarction. At this time point, infarcted regions will be well above the zero-crossing line and will therefore appear bright on these images. A phase-sensitive variant may be used that can correct for errors in choosing the inversion time. The standard LGE sequences are segmented acquisitions, acquired at every other heartbeat in order to allow normal myocardial regions to recover longitudinal magnetization before the next inversion pulse is applied. Therefore, they are constructed from the data of multiple heartbeats. Acquisition typically takes approximately 8-12 seconds. For patients with significant arrhythmia or difficulty with breath holding, single-shot LGE images using an SSFP IR sequence can provide a reasonable alternative in a fraction of the imaging time. These images are slightly lower in contrast to noise ratio and have a mildly reduced sensitivity for the detection of infarction. Nevertheless, they provide a satisfactory option in these circumstances. Single-shot LGE sequences may also be obtained with a long inversion time (550-600 milliseconds). These are quite useful in the detection of thrombi. On these images, thrombi will appear dark in contrast to normal myocardium and infarcted myocardium, which will be gray and bright in image intensity, respectively. Although predominately used for assessment of myocardial infarction and viability, the same LGE sequences can also be helpful in a variety of other circumstances, such as the detection of viral myocarditis and cardiac involvement by sarcoidosis. Flow-Sensitive Imaging Using Velocity-Encoded Sequences (Phase-Contrast Imaging) In this form of imaging, velocity-encoding phase shifts result from the sequential application of bipolar magnetic field gradients, which are composed of two lobes with opposite polarities. These opposed gradients will produce a phase shift with the first pulse that will be reversed by the second pulse. Therefore, stationary spins will acquire equal and opposite phases in the two gradients and will have no net phase at the end of the sequence. However, flowing spins passing through the imaging plane will acquire a net phase change, which will be dependent on their velocity in the direction of the flow-encoding gradients. These sequences are typically used in two situations: For quantification of gradients across stenotic valves and for measurement of blood flow. The peak gradient across a stenotic valve can be calculated using the Bernoulli equation, which is ΔP = 4V2, where velocity (V) is in meters per second and the pressure gradient (ΔP) is given in mm Hg. Flow is simply the sum of the velocities through a given area over time. These measurements are typically performed during postprocessing using a dedicated workstation. Standard CMR Examination At a minimum, a standard cardiac MR examination should provide a comprehensive evaluation of the structure and function of the heart. Additionally, in the vast majority of patients, myocardial tissue characterization, with an assessment of infarction, scarring, and viability, provides substantial clinical value at minimal time and cost. Therefore, in most centers, a standard exam includes cine images in the short-axis plane from above the mitral valve through the cardiac apex as well as in the standard orthogonal long-axis views (2-chamber, 4-chamber, and 3-chamber) or left ventricular outflow tract views. LGE images spatially matched to the cine images are also typically obtained. Many centers also obtain a stack of axial morphologic images throughout the chest. Additional sequences are added as needed for specific clinical indications, such as flow studies in cases of suspected valvular disease, T2 sequences for suspected myocarditis, etc. The following pages include suggested acquisition protocols for various indications in a tabular format and images demonstrating how to acquire the proper imaging planes in a step-by-step fashion. P.1:10

Tables Suggested Protocols by Indication

Indication

Left Ventricular Late Morphologi Perfusion Structure/Functio Gadolinium c Images Images n Cines Enhanceme nt Ischemic heart disease Standard Segmented (chronic) IR-FSE with inversion time set to null myocardium

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Other Modification s Single-shot IR-SSFP with long inversion time to exclude thrombus

Diagnostic Imaging Cardiovascular

Ischemic heart disease Standard (acute myocardial infarction)

Ischemic heart disease Standard (may (stress testing) perform after stress perfusion)

Cardiomyopathy Standard (hypertrophic cardiomyopathy, amyloid, Fabry disease)

Myocarditis/sarcoid

As above; Pre-contrast single-shot T2 is IR SSFP mayoptional (to be necessary look for in ill or edema, area arrhythmic at risk) patients Done after rest perfusion images

Segmented IR-FSE with inversion time set to null myocardium

Segmented IR-FSE with inversion time set to null myocardium Arrhythmogenic right Standard + stack Inversion ventricular of 4-chamber time of right dysplasia/cardiomyopat cines through ventricle hy right ventricular may be ˜ 30outflow tract; 40 right ventricular milliseconds 2-chamber view earlier than for left ventricle Iron overload Standard Segmented syndromes IR-FSE with inversion time set to null myocardium Valvular disorders

Standard (postcontrast cines are sometimes helpful)

To look for Single-shot microvascular IR-SSFP with obstruction long inversion time to exclude thrombus 3-4 images/beat during infusion of adenosine (140 µg/kg/min) or regadenoson, with rest images 10 minutes later Hypertrophic Inversion cardiomyopath time scout y patients may series show (modified abnormal Look-Locker) perfusion has despite normal characteristic coronaries abnormal pattern in amyloidosis Pre-contrast Normal (as Early T2 images opposed to in enhancement for edema acute coronary imaging for quantificatio syndrome global n patients) relative enhancement Looking for Fatfat is likely suppressed not useful LGE is sometimes recommende d

Multiecho short-axis GRE images to evaluate T2*

Standard + high- Segmented Aorta should resolution cine IR-FSE with be evaluated images through inversion in patients 22

Postprocessin g allows calculation of T2* from multiecho GRE sequence Velocityencoded images

Diagnostic Imaging Cardiovascular

affected valve

time set to with aortic null valve myocardium pathology

Congenital heart disease Standard + stack of 4-chamber and short-axis cine images through atria

Segmented IR-FSE with inversion time set to null myocardium

Mass

Standard

Tailored to mass

Pericardium

Standard + realtime cine images can show abnormal septal motion during provocative maneuvers

Segmented IR-FSE with inversion time set to null myocardium

through the affected valve to measure gradient Axial, May be helpfulVelocitysagittal, and in encoded coronal demonstrating images images shunts through the throughout proximal chest aorta and pulmonary artery to quantify Qp:Qs T1 and T2 Very helpful inSingle-shot images are assessing IR-SSFP with often lesion long helpful, with vascularity inversion fattime to suppression exclude as needed thrombus FSE images Tagged may show images may pericardial confirm thickening abnormal more clearly adherence of than HASTE pericardial or SSFP layers images

Diagnostic Findings in Specific Cardiomyopathies

Suspected Diagnosis Amyloid

Arrhythmogenic right ventricular dysplasia/cardiomyopathy Fabry disease

Hypertrophic cardiomyopathy

Myocarditis

Structure/Function LGE Module Module Thick ventricles, dilated Diffuse atria subendocardial enhancement Large right ventricle with2/3 of patients poor function, regional show right wall motion ventricular abnormalities enhancement Concentric hypertrophy Midwall enhancement of inferolateral basal wall Asymmetric, concentric, Positive at right or apical forms ventricular insertion sites/thickened areas Focal thickening, wall Lateral epicardial motion abnormality or midseptal patterns common

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Other Difficulty finding null point on inversion time scout series Null point of right ventricle may be slightly earlier than for left ventricle Predominantly men

Extent of LGE correlates with risk factors for sudden death

T2-weighted images may show edema; early relative global hyperenhancement

Diagnostic Imaging Cardiovascular

Sarcoid

Focal thickening, wall motion abnormality

Patchy uptake with Mediastinal/hilar basal/septal adenopathy is often predominance noted

P.1:11

Image Gallery

(Left) Axial low-resolution SSFP scout image is used to begin scan planning. To acquire the scout 2-chamber long-axis view, a line is placed bisecting the left ventricular (LV) apex and the mitral valve. (Right) Vertical long-axis (2-chamber) scout SSFP view is then used to obtain the 4-chamber scout view. The imaging plane is acquired by placing a line paralleling the long axis of the LV through the LV apex and left atrium as shown. This results in the low-resolution 4chamber scout SSFP image.

(Left) Four-chamber view scout SSFP image is used to obtain the short-axis scout image for planning the stack of shortaxis cine images. The imaging plane is placed perpendicular to the septum and lateral wall and parallels the mitral valve as shown. (Right) Short-axis scout SSFP image is then copied using the standard, high-resolution cine SSFP technique after assuring that no wrap artifact has been produced and that the image is appropriately centered.

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Diagnostic Imaging Cardiovascular

(Left) Short-axis stack of SSFP cine images is then acquired from the mitral valve plane through the LV apex using their positions on the 4-chamber view to assure proper coverage. A diastolic image is used as the plane of the mitral valve may move toward the apex in systole. (Right) Short-axis SSFP cine image is used to plan the 3-chamber or left ventricular outflow tract view (LVOT) by placing an imaging plane through the mitral valve and aortic valve as seen on the basilar short-axis view. P.1:12

(Left) Short-axis MR cine image is used to plan the high-resolution 4-chamber cine view by placing a line through the basal septum that is roughly perpendicular to the septum and parallel to the inferior margin of the heart. Care should be taken to avoid the inferior aspect of the aortic valve, which can be confused with a septal defect if included. (Right) Short-axis MR cine is used to plan the 2-chamber view by placing an imaging plane to bisect the anterior and inferior LV walls.

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Diagnostic Imaging Cardiovascular

(Left) Axial double inversion-recovery FSE image (HASTE) of a patient with D-transposition with a systemic right ventricle shows the resultant right ventricular hypertrophy. Note the excellent depiction of the myocardium and vessels. (Right) Axial SSFP single-shot image of a patient with a type A aortic dissection shows the intimal flap in the ascending and descending aorta. Note also the excellent delineation of the right inferior pulmonary vein .

(Left) Short-axis T1WI FSE MR shows an atrial myxoma centered in the fossa ovalis and protruding into both atria. (Right) Short-axis T2WI FSE MR of a biatrial myxoma shows that it is hyperintense on T2 imaging, indicative of its gelatinous composition. Note that this gated technique results in high-resolution motion-free images that provide tissue characterization. P.1:13

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Diagnostic Imaging Cardiovascular

(Left) LV short-axis MR cine SSFP image in diastole shows minimal swelling of the inferior wall due to acute myocardial infarction (MI) . The sequence shows clear contrast between the myocardium and the blood pool, facilitating volumetric analysis. Also note the subtle signal increase of the inferior wall due to edema. (Right) LV short-axis T2WI FSE MR of an acute inferior MI shows increased signal in the area of infarction . Note the area of decreased signal centrally due to intramural hematoma.

(Left) LV short-axis late gadolinium enhancement (LGE) image of a large inferior MI shows that the infarct is demonstrated as an area of increased signal intensity while the normal myocardium has very low signal . The low-signal foci within the area of infarction represent regions of hemorrhagic necrosis and are termed “no-reflow zones” . (Right) LV short-axis MR perfusion image of a large inferior MI shows diminished contrast uptake in the inferior wall due to microvascular obstruction.

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Diagnostic Imaging Cardiovascular

(Left) Four-chamber view LGE image using a long inversion time (600 milliseconds) demonstrates thrombi present in both ventricles. This sequence is often helpful in characterizing thrombi, which can have a confusing “etched” appearance on standard LGE images. (Right) Oblique velocity-encoded phase-contrast images of a bicuspid aortic valve show good delineation of the valve morphology on the magnitude image , while the phase image allows gradient and flow calculation.

Cardiac Anatomy GENERAL ANATOMY AND FUNCTION Anatomy  Cardiac chambers o Right atrium (RA), right ventricle (RV), left atrium (LA), left ventricle (LV)  Cardiac valves o Atrioventricular (AV) valves  Tricuspid, mitral o Semilunar valves  Pulmonic, aortic  Cardiac structure o Epicardium: Serous visceral pericardium o Myocardium: Specialized cardiac muscle that forms atrial and ventricular walls o Endocardium: Thin layer of cells that lines internal surfaces of cardiac chambers and participates in cardiac contraction Function  Pump action o Delivery of deoxygenated blood to alveolar-capillary interface o Delivery of oxygenated blood to tissues  Cardiac conduction system o Sinoatrial node  Cardiac pacemaker; atrial contraction  Superior end of crista terminalis at superior vena cava orifice o Atrioventricular node  In atrial septum, near coronary sinus orifice, close to attachment of septal cusp of tricuspid valve  Receives impulse generated at sinoatrial node and propagates it to ventricles  Produces ventricular contraction o Atrioventricular bundle  Continuation of AV node along interventricular septum; divides into right and left bundle branches o Right bundle branch  Continues along right side of interventricular septum to reach subendocardial Purkinje fibers 28

Diagnostic Imaging Cardiovascular o

Left bundle branch  Continues along left side of interventricular septum to apex to reach subendocardial Purkinje fibers CARDIAC SHAPE AND ORIENTATION Shape  Pyramidal Orientation  Position analogous to pyramid on its side  Apex oriented anteriorly, inferiorly, and to the left CARDIAC SURFACES Posterior Surface (Base)  Quadrilateral shape  Faces posteriorly  Structures: LA, small portion of RA, central great veins Apex  Faces anteriorly, inferiorly, and to the left  Structures: Inferolateral LV Anterior Surface  Faces anteriorly  Structures: RV (anterior free wall), portions of RA and LV Diaphragmatic Surface  Faces inferiorly  Rests on diaphragm  Structures: LV, portion of RV Left Pulmonary Surface  Faces left lung  Structures: LV, portion of LA Right Pulmonary Surface  Faces right lung  Structure: RA CARDIAC BORDERS (MARGINS) Upper Border  Not well appreciated on imaging Inferior (Acute) Border  Edge between anterior and diaphragmatic surfaces  Structures: RV, portion of LV Obtuse (Left) Border  Between anterior and left pulmonary surfaces  Curved morphology  From left atrial appendage to apex  Structures: LV, portion of LA appendage Right Border  Analogous to right pulmonary surface CARDIAC SULCI OR GROOVES General Features  Heart divided into chambers  Internal cardiac partitions demarcate chamber boundaries  Sulci: External grooves related to internal partitions Atrioventricular Sulcus or Groove (Coronary Sulcus)  Surrounds heart, separates atria from ventricles  Structures: Right coronary/circumflex branch of left coronary artery, small cardiac vein, great cardiac vein, coronary sinus Anterior and Posterior Interventricular Sulci or Grooves  Separate ventricles  Anterior interventricular groove or sulcus o Anterior heart surface o Structures: Left anterior descending (LAD) coronary artery, anterior interventricular vein  Posterior interventricular groove or sulcus 29

Diagnostic Imaging Cardiovascular o o

 P.1:15

Diaphragmatic heart surface Structures: Posterior descending (interventricular) coronary artery, middle cardiac vein (posterior interventricular vein), occasionally distal wrap-around LAD Anterior and posterior interventricular sulci continuous inferiorly to left of apex

CARDIAC CHAMBERS Right Atrium  Forms right cardiac border and portion of anterior surface  Receives deoxygenated blood through o Superior vena cava: Superior posterior RA o Inferior vena cava: Inferior posterior RA o Coronary sinus: Inferior posterior RA  Thebesian valve: Prevents reflux of blood back into coronary sinus from RA o Thebesian veins: Small veins that drain subendocardium o Anterior cardiac vein: Venous return from anterior RV  Blood exits through AV tricuspid valve  Structures o Compartmentalized by external sulcus terminalis cordis  From right of superior vena cava to right of inferior vena cava o Compartmentalized by internal crista terminalis  Smooth ridge that begins at roof of atrium anterior to superior vena cava orifice and extends to anterior lip of inferior vena cava orifice o Sinus of venae cavae, posterior to crista terminalis o RA proper  Anterior to crista terminalis  Wall covered by ridges called pectinate muscles  RA appendage (auricle) o Vascular orifices  Orifice of superior vena cava, orifices and valves of inferior vena cava and coronary sinus o Interatrial septum  Fossa ovalis: Depression in septum above orifice of inferior vena cava  Limbus fossa ovalis: Margin of fossa ovalis  Fossa ovalis marks location of primitive foramen ovale, which allows oxygenated blood to enter LA and bypass lungs in utero Right Ventricle  Forms anterior cardiac surface and small portion of diaphragmatic surface  Structures o Conus arteriosus: Smooth-walled RV infundibulum or outflow tract o RV inflow tract, lined by trabeculae carneae, forms ridges and bridges o Papillary muscles are trabeculae carneae attached to ventricular surface and chordae tendineae; connect chordae tendineae to free edges of tricuspid valve  Anterior papillary muscle: Largest, arises from anterior ventricular wall  Posterior papillary muscle: Some chordae tendineae arise directly from ventricular wall  Septal papillary muscle: Most inconsistent o Septomarginal trabecula or moderator band  Forms bridge between lower interventricular septum and base of anterior papillary muscle Left Atrium  Forms base or posterior cardiac surface  Structures o Posterior or inflow portion: Smooth-walled, receives pulmonary veins o Anterior or outflow portion: Continuous with LA appendage, lined by pectinate muscles o Interatrial septum  Contains valve of foramen ovale, prevents blood from passing from LA to RA  Valve of foramen ovale may provide passage between atria during cardiac instrumentation Left Ventricle  Contributions to anterior, diaphragmatic, and left pulmonary cardiac surfaces; forms apex  Thickest myocardium 30

Diagnostic Imaging Cardiovascular 

Structures o Fine, delicate trabeculae carneae o Papillary muscles larger than in RV  Anterior papillary muscle  Posterior papillary muscle o Interventricular septum  Thick muscular portion forms major part of septum  Membranous portion CARDIAC VALVES Tricuspid Valve  3 cusps attached to fibrous ring o Anterior, septal, posterior  Anatomy of right AV valve o Free margins attached to chordae tendineae  Cusps continuous with each other at their bases, forming the commissures o Chordae tendineae from 2 papillary muscles attach to each cusp  Separated from pulmonic valve by muscular ridge (crista supraventricularis) Pulmonic Valve  3 semilunar cusps o Left, right, anterior  Anatomy of semilunar cusps o Free edges project into lumen of pulmonary trunk forming sinuses o Each cusp has thick central focus, the nodule of semilunar cusp o Each cusp has thin lateral portion, the lunule of semilunar cusp Mitral Valve  2 cusps attached to fibrous ring o Anterior and posterior, divided in 3 subdivisions each (A1, A2, A3 and P1, P2, P3; 1 is superior)  Anatomy of left AV valve o Cusps continuous with each other at commissures o Chordae tendineae attach papillary muscles to free borders of cusps  In fibrous continuity with aortic valve Aortic Valve  3 semilunar cusps o Right, left, and noncoronary (or posterior)  3 sinuses of Valsalva o Right coronary artery originates from right sinus o Left coronary artery originates from left sinus o Noncoronary sinus always faces interatrial septum P.1:16

IMAGING THE HEART Radiography  Analysis of cardiac borders and surfaces o Right cardiac border: RA o Left cardiac border: LA appendage and LV o Anterior cardiac surface: RV o Posterior cardiac surface: LA and LV  Variations in cardiac morphology o Infancy: Prominent cardiothymic silhouette o Childhood, adolescence, and young adulthood: Prominent pulmonary trunk o Adulthood: Progressive LV configuration with dominant left-sided structures and concavity of upper left cardiac border  Analysis of cardiac size o Cardiothoracic ratio  Maximum transverse cardiac diameter to transverse thoracic diameter ≤ 0.55  Influenced by rotation, lung volume, projection o Analysis of individual chamber enlargement 31

Diagnostic Imaging Cardiovascular  Analysis of abnormal cardiac density/calcification CT/MR Anatomy  Right atrium o RA appendage (trabeculated) anterior and superior to RV o Crista terminalis: Vertical ridge in RA extending from superior to inferior venae cavae  Left atrium o Most superior and posterior cardiac chamber o LA appendage (trabeculated) anterior and superior to LV o Smooth muscle ridge at junction of LA appendage and central left superior pulmonary vein (a.k.a. Coumadin ridge)  Interatrial septum o Thin structure, difficult identification on CT o Increased visibility with fat deposition  Fat spares fossa ovalis and may allow its identification  Right ventricle o Most anterior cardiac chamber, anterior heart surface o Heavy trabeculations, thin wall  Moderator band: Connects anterior papillary muscle to interventricular septum near RV apex; contains right bundle branch o Anterior, posterior, septal papillary muscles  Left ventricle o Posterior and diaphragmatic cardiac surfaces o Thicker than RV, less trabeculated o Anterior and posterior papillary muscles  Interventricular septum o Thicker than interatrial septum  Valves o Imaging in longitudinal and perpendicular planes  On contrast-enhanced CT and bright-blood cardiac MR: Thin low-attenuation/signal structures o Assessment of function, morphology, calcification CT/MR  Assessment of cardiac chambers, valves, myocardium o Size, morphology, wall thickness, calcification, function  Short-axis view o Cross-section through short axis of LV cavity and bodies of papillary muscles  Paraseptal long-axis (2-chamber) view o Display of LA and LV chambers o Evaluation of mitral (left atrioventricular [AV]) valve o Excellent visualization of anterior and inferior LV myocardium  4-chamber view o Display of 4 cardiac chambers and AV valves  LV outflow tract view o Display of LA, LV, LV outflow tract, and aorta  RV outflow tract view o Display of RA, RV, RV outflow tract, and main pulmonary artery IMAGING CLUES TO IDENTIFY MORPHOLOGIC RIGHT AND LEFT VENTRICLES Anatomic Right Ventricle  Muscular infundibulum separates tricuspid and pulmonic valves  Coarse trabeculae with trabeculations along interventricular septum  Papillary muscles attached to interventricular septum and free wall  Apical moderator band  Septal tricuspid valve leaflet inserts more apically than matching mitral valve leaflet Anatomic Left Ventricle  Fibrous continuity between mitral and aortic valves  Thin and delicate trabeculae with smooth septal surface  Papillary muscles attached only to free walls IMAGING CLUES TO IDENTIFY MORPHOLOGIC RIGHT AND LEFT ATRIA 32

Diagnostic Imaging Cardiovascular Anatomic Right Atrium  RA appendage has broad opening with triangular shape  Rule of venoatrial concordance o Chamber that receives inferior vena caval inflow is almost always the morphologic RA  Generally on same side as morphologic right trilobed lung Anatomic Left Atrium  Finger-like LA appendage with narrow orifice and pointed appearance  Generally on same side as morphologic left bilobed lung  Important to not mistake normal linear pectinate muscle or Coumadin ridge for thrombus RELATED REFERENCES 1. Galea N et al: Right ventricular cardiovascular magnetic resonance imaging: normal anatomy and spectrum of pathological findings. Insights Imaging. 4(2):213-23, 2013 2. Debonnaire P et al: Contemporary imaging of normal mitral valve anatomy and function. Curr Opin Cardiol. 27(5):455-64, 2012 3. Venkatesh V et al: Normal magnetic resonance imaging of the thorax. Magn Reson Imaging Clin N Am. 19(3):489506, viii, 2011 P.1:17

Image Gallery ANTERIOR VIEW OF THE HEART, ANTERIOR CHEST WALL REMOVED

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Diagnostic Imaging Cardiovascular Graphic illustrates the location of the heart with respect to the rest of the structures and organs in the thorax. The heart is surrounded by the pericardium and has a pyramidal shape with its apex oriented inferiorly and towards the left side. The cardiac base faces posteriorly. The 4 heart chambers connect with the great pulmonary and systemic vessels. The heart receives blood from the systemic and pulmonary circulations via the systemic and pulmonary veins, respectively. The blood is then pumped into the pulmonary circulation for delivery to the capillary-alveolar interface and into the systemic circulation for delivery to the tissues and organs of the body. P.1:18

ANATOMY OF HEART SURFACES, MARGINS, AND SULCI

Graphic depicts the surface anatomy of the heart. The heart has a pyramidal shape with a base and an apex. It has anterior, diaphragmatic, posterior, and right and left pulmonary surfaces. The anterior surface is formed by the right and left ventricles with small contributions from the right atrium and left atrial appendage. The obtuse (left) cardiac border separates the anterior and left pulmonary surfaces. The inferior (acute) cardiac border separates the anterior and diaphragmatic surfaces. External sulci correspond to internal partitions that divide the heart into chambers. There are anterior and posterior interventricular sulci and a coronary sulcus (atrioventricular groove). The coronary sulcus is circumferential and separates the atria from the ventricles. The anterior and posterior interventricular grooves separate the ventricles. P.1:19

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Diagnostic Imaging Cardiovascular

(Top) Graphic shows the posterior heart surface, or base of the heart, which is formed by the left atrium, a small portion of the right atrium, the paired superior and inferior pulmonary veins, and the superior and inferior venae cavae, which fix the heart base to the pericardium. The left atrioventricular groove is seen at the junction of the left atrium and ventricle. (Bottom) Graphic shows the diaphragmatic heart surface, which is formed by the right and left ventricles and is separated from the heart base by the coronary sulcus (atrioventricular groove). The inferior (acute) cardiac border separates the diaphragmatic surface from the anterior heart surface. The posterior interventricular sulcus (or groove) marks the location of the interventricular septum. P.1:20

RADIOGRAPHY OF THE HEART

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Diagnostic Imaging Cardiovascular

(Top) Normal PA chest radiograph shows the right and left (or obtuse) cardiac borders. The diaphragmatic cardiac surface is not visible radiographically. The right cardiac border is formed by the right atrium and is analogous to the right pulmonary cardiac surface. The left (or obtuse) cardiac border is formed by the left ventricle and a small portion of the left atrium, the left atrial appendage. (Bottom) Normal left lateral chest radiograph (same patient) shows the anterior and posterior cardiac surfaces. The anterior surface is formed by the right ventricle. The base of the heart (or posterior surface) is formed by the left atrium. P.1:21

CT OF HEART SURFACES, BORDERS, AND SULCI

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Diagnostic Imaging Cardiovascular

(Top) Normal coronal contrast-enhanced chest CT image through the aortic valve demonstrates the cardiac surfaces, borders, and sulci. This image shows the right and obtuse (left) cardiac borders. The right cardiac border is analogous to the right pulmonary cardiac surface. The diaphragmatic cardiac surface is also visible. Fat is present in the right atrioventricular groove, which demarcates the boundary between the atria and ventricles. (Bottom) Normal sagittal contrast-enhanced chest CT image (same patient) demonstrates the base of the heart formed primarily by the left atrium, the diaphragmatic cardiac surface formed by the left and right ventricles, and the anterior cardiac surface formed by the right ventricle. A portion of the coronary sulcus (or atrioventricular groove) is also seen. P.1:22

ANATOMY OF ANTERIOR HEART SURFACE AND RIGHT ATRIUM

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Diagnostic Imaging Cardiovascular

(Top) Graphic demonstrates the anatomy of the right cardiac chambers. Note that the anterior surface of the heart is predominantly formed by the right ventricle and portions of the right atrium and left ventricle. The right atrial appendage is also shown. (Bottom) Graphic of the interior of the right atrium shows trabeculated (pectinate muscles) and smooth regions separated by the crista terminalis. The posterior smooth portion (sinus of the venae cavae) receives the superior vena cava superiorly and the inferior vena cava inferiorly and the coronary sinus. The anterior trabeculated portion is known as the right atrium proper. The interatrial septum contains the fossa ovalis, which marks the location of the embryonic foramen ovale. P.1:23

ANATOMY OF RIGHT VENTRICLE

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Diagnostic Imaging Cardiovascular

Graphic of the interior of the right ventricle shows trabeculated and smooth areas. The proximal (inflow portion) right ventricle is characterized by the trabeculae carneae. Some of these form papillary muscles, which attach to the free edges of the tricuspid (right atrioventricular) valve cusps via chordae tendineae. There are anterior, septal, and posterior papillary muscles. The septal papillary muscle is not seen in all individuals. A thick trabecula carnea connects the interventricular septum to the anterior papillary muscle and is known as the moderator band or septomarginal trabecula. The right ventricular outflow tract leads to the pulmonic valve and is characterized by its smooth walls. P.1:24

CT OF RIGHT HEART CHAMBERS

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Diagnostic Imaging Cardiovascular

(Top) Normal contrast-enhanced cardiac gated axial CT image through the junction of the superior vena cava and right atrium shows the anteriorly oriented triangular right atrial appendage. (Middle) Normal contrast-enhanced cardiac gated axial CT image through the upper heart (same patient) shows the orifice of the superior vena cava as blood enters the right atrium. The right atrium is located anterior and to the right of the left atrium and the ascending aorta. The right ventricle is located anterior and to the left of the ascending aorta. (Bottom) Normal contrast-enhanced cardiac gated axial CT image through the upper heart (same patient) demonstrates the superior aspects of the right atrium and ventricle. These chambers are separated by the coronary sulcus. The crista terminalis courses between the orifices of the venae cavae and separates the atrium proper from the sinus of the venae cavae. P.1:25

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Diagnostic Imaging Cardiovascular

(Top) Normal contrast-enhanced cardiac gated axial CT image through the mid heart (same patient) shows the mid portions of the right atrium and ventricle. The chambers are separated by the coronary sulcus, also known as atrioventricular groove. The crista terminalis is seen along the posterolateral right atrial wall. (Middle) Normal contrast-enhanced cardiac gated axial CT image through the inferior heart (same patient) shows the trabeculae carneae that characterize the internal surface of the wall of the right ventricle. The septomarginal trabecula (or moderator band) courses from the inferior interventricular septum to the base of the anterior papillary muscle. (Bottom) Normal contrast-enhanced cardiac gated axial CT image through the inferior aspect of the heart (same patient) shows the junctions of the inferior vena cava and coronary sinus with the right atrium. Note the fine trabeculations of the right ventricular myocardium produced by the trabeculae carneae. The right ventricular myocardium is very thin when compared with that of the left ventricle. P.1:26

ANATOMY OF POSTERIOR HEART SURFACE AND LEFT ATRIUM

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Diagnostic Imaging Cardiovascular

(Top) Graphic illustrates the anatomy of the left cardiac chambers. This posterior view of the heart shows the heart base formed predominantly by the left atrium and a small portion of the right atrium. The left atrium receives the paired superior and inferior pulmonary veins. (Bottom) Graphic shows the internal anatomy of the left atrium, which has smooth and trabeculated inner surfaces. The left atrial appendage is characterized by its trabeculated inner surface produced by the pectinate muscles. The valve of the fossa ovalis is noted on the interatrial septum and prevents passage of blood between the atria. P.1:27

ANATOMY OF LEFT VENTRICLE

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Diagnostic Imaging Cardiovascular

Graphic shows the internal anatomy of the left ventricle, which has a thicker myocardium but thinner and more delicate trabeculae carneae than the right ventricle. The anterior and posterior papillary muscles attach to the anterior and posterior leaflets of the mitral valve, respectively. P.1:28

CT OF LEFT HEART CHAMBERS

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Diagnostic Imaging Cardiovascular

(Top) Contrast-enhanced axial chest CT image through the superior aspect of the left atrium demonstrates the relationship between the left atrial appendage and left superior pulmonary vein and the smooth or nodular ridge at the junction of these 2 structures. (Middle) Contrast-enhanced axial chest CT image through the right superior pulmonary vein (same patient) demonstrates the trabeculated appearance of the left atrial appendage (pectinate muscles) in contrast to the smooth internal wall of the left atrium proper. The so-called Coumadin ridge is located between the left superior pulmonary vein and the left atrial appendage. It is named so as it can cause an artefact that can be mistaken for left atrial appendage thrombus on transesophageal echocardiography. (Bottom) Contrastenhanced axial chest CT image through the superior left ventricle (same patient) demonstrates the thickness of the normal left ventricular wall. The trabeculae carneae produce an irregular endoluminal ventricular surface. Note the smooth left ventricular outflow tract. P.1:29

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Diagnostic Imaging Cardiovascular

(Top) Contrast-enhanced axial chest CT image through the superior left ventricle (same patient) demonstrates the thickness of the normal left ventricular wall. The mitral valve leaflets are thin and open during ventricular diastole. (Middle) Contrast-enhanced axial chest CT image through the mid portion of the ventricles (same patient) demonstrates internal filling defects produced by the trabeculae carneae. Compare the thickness of the left ventricular myocardium with that of the normal thinner right ventricular myocardium. (Bottom) Contrast-enhanced axial chest CT image through the inferior heart (same patient) demonstrates the inferior portion of the left ventricle and the trabeculated appearance of its lumen. Note the trabeculated appearance of the right ventricular chamber. P.1:30

CORONAL CT OF NORMAL HEART

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Diagnostic Imaging Cardiovascular

(Top) Coronal contrast-enhanced chest CT image through the heart demonstrates the anteriorly located trabeculated right ventricle leading to the superiorly located and relatively smooth right ventricular outflow tract. The left ventricle forms the left cardiac border. (Middle) Coronal contrast-enhanced chest CT image through the pulmonary trunk (same patient) demonstrates the right atrial appendage. The right ventricle is anterior and to the left of the right atrium. The left ventricle forms the left heart border and has a thicker wall than does the right ventricle. (Bottom) Coronal contrast-enhanced chest CT image through the aortic arch (same patient) shows the smooth internal wall of the left ventricular outflow tract compared with the trabeculated inner surface of left ventricle proper. The atrioventricular groove separates the right atrium and right ventricle. The right atrium forms the right heart border on radiography. P.1:31

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Diagnostic Imaging Cardiovascular

(Top) Coronal contrast-enhanced chest CT image through the posterior aspect of the right atrium (same patient) shows the junction of the right atrium with the superior and inferior venae cavae. The left atrial appendage is superior to the left ventricle and forms a portion of the obtuse (left) cardiac border. A prominent papillary muscle is outlined by contrast within the left ventricle. (Middle) Coronal contrast-enhanced chest CT image through the mid portion of the left atrium (same patient) shows the junction of the left atrium with the bilateral superior pulmonary veins. (Bottom) Coronal contrast-enhanced chest CT image through the posterior aspect of the left atrium (same patient) shows the bilateral inferior pulmonary veins coursing obliquely into the left atrium. P.1:32

SAGITTAL CT OF NORMAL HEART

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Diagnostic Imaging Cardiovascular

(Top) Sagittal contrast-enhanced chest CT images show the sagittal anatomy of the heart. The images are presented from left to right. The left ventricle has a thicker myocardium when compared with the right and exhibits well-defined papillary muscles. The right ventricle forms the anterior cardiac surface. (Middle) Sagittal contrast-enhanced chest CT image through the right ventricular outflow tract (same patient) shows the anterior location of the right ventricle and the posterosuperior course of the right ventricular outflow tract and pulmonary trunk. The left ventricle is posterior to the right ventricle. The left atrium is superior to the left ventricle and is separated from it by the coronary sulcus, which is also known as the atrioventricular groove. (Bottom) Sagittal contrast-enhanced chest CT image through the mid heart (same patient) shows the central location of the left ventricular outflow tract and ascending aorta. P.1:33

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Diagnostic Imaging Cardiovascular

(Top) Sagittal contrast-enhanced chest CT image through the aortic valve (same patient) shows the anatomic location of the right ventricle, which forms the anterior cardiac surface and contributes to the diaphragmatic cardiac surface. The left atrium forms the posterior surface (or base) of the heart. (Middle) Sagittal contrast-enhanced chest CT image through the right heart chambers (same patient) shows the posterior location of the right atrium with respect to the right ventricle and its connection with the inferior vena cava. (Bottom) Sagittal contrast-enhanced chest CT image through the right side of the heart (same patient) shows the connection of the venae cavae with the right atrium. The right ventricle is located anteriorly and separated from the right atrium by the coronary sulcus. P.1:34

CT OF RIGHT ATRIUM

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Diagnostic Imaging Cardiovascular

(Top) Nonenhanced chest CT demonstrates mild fatty infiltration of the interatrial septum that spares the fossa ovalis and allows its localization in the axial plane. This appearance may mimic an atrial septal defect. (Middle) Contrastenhanced CTA shows a dilated right atrium. Note unopacified contrast in the coronary sinus. The thebesian valve prevents reflux of blood from the right atrium into the coronary sinus. (Bottom) Four-chamber view from a contrastenhanced cardiac CT shows the linear ridge of tissue called the crista terminalis, which must be differentiated from thrombus. The crista terminalis is a smooth ridge of tissue that begins at the roof of the right atrium anterior to the superior vena cava orifice and extends inferiorly to the anterior lip of the inferior vena cava. P.1:35

CT OF LEFT ATRIUM

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Diagnostic Imaging Cardiovascular

(Top) CT image demonstrates the nodular appearance of the ridge at the junction of the left atrium and left superior pulmonary vein adjacent to the left atrial appendage,which is also known as the Coumadin ridge as it can be mistaken for thrombus at transesophageal echocardiography. Axial image through the superior aspect of the left atrium demonstrates the constant relationship between the left superior pulmonary vein and the adjacent left atrial appendage. The left atrial appendage is always anterior and inferior to the left superior pulmonary vein. (Middle) Coronal CT image through the left atrial appendage (same patient) demonstrates the normal soft tissue ridge that occurs at the junction of the left atrium with the left superior pulmonary vein adjacent to the left atrial appendage. (Bottom) Posterior 3D volume-rendered image from a CTA shows the normal appearance of the pulmonary veins. P.1:36

CT, 4-CHAMBER VIEW

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Diagnostic Imaging Cardiovascular

(Top) Contrast-enhanced gated 4-chamber cardiac CT image allows simultaneous evaluation of the 4 cardiac chambers. The right chambers are projected anterolateral to the left heart chambers and are less opacified with contrast. The mitral valve leaflets manifest as thin linear soft tissue structures between the left atrium and left ventricle. (Bottom) Four-chamber gated cardiac CT image (same patient) demonstrates a normal mitral valve. The 4 cardiac chambers and the coronary (atrioventricular) and interventricular sulci (grooves) are demonstrated. The interventricular groove is located slightly to the right of the cardiac apex. P.1:37

ECHOCARDIOGRAPHY, 4-CHAMBER AND ARCH VIEWS

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Diagnostic Imaging Cardiovascular

(Top) Transthoracic echocardiography apical 4-chamber view in systole shows right atrium, closed tricuspid valve, and right ventricle on the left side of the image, and left atrium (with pulmonary vein inflow), closed mitral valve, and left ventricle with papillary muscles on the right side of the image. The atrial and ventricular walls between the chambers are the atrial and ventricular septa. Note that the insertion of septal tricuspid valve leaflet is more apical compared with the respective mitral leaflet insertion. (Bottom) Transthoracic echocardiography suprasternal notch view of the aortic arch demonstrates the aortic root and arch and the proximal descending thoracic aorta. Note that the right main pulmonary artery and the left main stem bronchus (or rather its shadowing from the contained air) are shown in cross section. P.1:38

CT, 2-CHAMBER VIEW

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(Top) Paraseptal long-axis (2-chamber) contrast-enhanced gated cardiac CT image shows the anatomy of the left ventricle and left atrium. Note the intimate relationship of the left superior pulmonary vein and left atrial appendage with an intervening nodular soft tissue ridge, which is also known as the Coumadin ridge. The left atrial appendage exhibits a trabeculated internal surface produced by the pectinate muscles. The left ventricle, the thickness of its wall, and its papillary muscles are well visualized. (Bottom) Paraseptal long-axis (2-chamber) contrast-enhanced gated cardiac CT image through the mitral valve obtained during systole (same patient) demonstrates coaptation of the thin anterior and posterior valve cusps. The papillary muscles manifest as rounded filling defects within the contrast-filled left ventricular chamber. P.1:39

ECHOCARDIOGRAPHY, 2- AND 3-CHAMBER VIEWS

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(Top) Transthoracic echocardiogram apical 2-chamber view in end-systole shows left ventricular cavity, closed mitral valve, and left atrium. Due to shadowing from interposed lung, only partial visualization of the anterior left ventricular wall is possible. (Middle) Apical 3-chamber view in end-systole shows left atrium, closed mitral valve, left ventricle, left ventricular outflow tract, and open aortic valve. (Bottom) Apical 3-chamber view with Doppler flow superimposed shows normal flow across the aortic valve. Note that Doppler flow is only calculated in the selected triangular section. P.1:40

CT, SHORT-AXIS VIEW

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(Top) Contrast-enhanced cardiac gated short-axis CT image shows the ventricular chambers. The right ventricle is located anteriorly and has a thin wall. The right ventricular outflow tract courses superiorly and posteriorly to give off the pulmonary trunk. The left ventricle is posterior and has a thicker myocardium than the right ventricle. The 2 chambers are separated by the interventricular sulcus (or groove). (Middle) Contrast-enhanced cardiac gated shortaxis CT image through the mid heart (same patient) shows the anatomy of the left ventricular chamber. The papillary muscles manifest as filling defects within the contrast-filled left ventricular lumen. (Bottom) Contrast-enhanced cardiac gated short-axis CT image obtained just medial to the left apex (same patient) demonstrates trabeculations in both ventricular chambers produced by trabeculae carneae. The right ventricle forms the anterior heart surface. P.1:41

ECHOCARDIOGRAPHY, SHORT-AXIS VIEW

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(Top) End-diastolic short-axis transthoracic echocardiography view at the basal left ventricular level shows the left ventricular lumen and walls at the base with the mitral valve apparatus partially visualized. The right ventricle is located anteriorly and is incompletely visualized due to acoustic window restrictions. The right ventricular outflow tract is located near the probe. Note acoustic shadowing at the lung interfaces. (Middle) The midventricular level demonstrates the papillary muscles. Note absence of trabeculation insertions at the left ventricular side of the ventricular septum. The right ventricular septal wall gives rise to several trabeculae. (Bottom) Short-axis view through the apical level shows the most trabeculated portion of the chambers. This area is often difficult to visualize because of acoustic window restrictions due to bone (sternum and ribs) and lung. P.1:42

MR OF NORMAL HEART, SHORT-AXIS VIEW

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(Top) Short-axis T2-weighted double inversion-recovery black blood MR image showing the basal aspect of the heart, which is made up of the right and left atria. (Middle) Short-axis T2-weighted double inversion-recovery black blood MR image slightly more apically (same patient) shows the pulmonic valve and right ventricular outflow tract. (Bottom) Short-axis T2-weighted double inversion-recovery black blood MR image through the mid ventricular level (same patient) shows a papillary muscle of the left ventricle. The midventricular level is best identified on the short-axis view by identifying the papillary muscles. The left ventricular interventricular septum is typically smooth, whereas the right ventricular interventricular septum is trabeculated. P.1:43

MR OF NORMAL HEART, SAGITTAL VIEW

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(Top) Sagittal T1-weighted MR images of the chest are presented from left to right. Image through the ventricles demonstrates the trabeculated internal surfaces of the ventricles. Note the thickness of the left ventricular myocardium relative to that of the right. (Middle) Sagittal T1-weighted MR image through the pulmonary outflow tract (same patient) shows the anterior location of the right ventricle, which forms the anterior cardiac surface. The left atrium is located posterior and superior to the left ventricle and forms the base of the heart. The right ventricle forms the anterior heart surface. The right and left ventricles form the diaphragmatic cardiac surface. (Bottom) Sagittal T1-weighted MR image though the root of the aorta (same patient) shows the aortic root's central location with respect to the vessels and heart chambers and demonstrates the anatomic relationship of the right and left atria. P.1:44

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(Top) Sagittal T1-weighted MR image through the ascending aorta (same patient) demonstrates the posterior location of the atria with respect to the anteriorly located trabeculated right ventricle. The proximal ascending aorta and its root are located in the center of the heart. (Bottom) Sagittal T1-weighted MR image through the right atrium (same patient) demonstrates the posterosuperior and posteroinferior connections of the right atrium with the superior and inferior venae cavae, respectively. There is visualization of a small portion of the anteriorly located right ventricle. The posteriorly located left atrium, which forms a large portion of the base of the heart is also visualized. The coronary sulcus (or atrioventricular groove) is located between the atria and ventricles. P.1:45

ANATOMY OF CARDIAC SKELETON AND HEART VALVES

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Diagnostic Imaging Cardiovascular

Graphic demonstrates the anatomy of the cardiac skeleton located between the atria and ventricles. The cardiac skeleton consists of thick fibrous connective tissue and provides support for the valve orifices and the areas of attachment for the valve cusps. In this graphic, the atria have been “removed” to expose the cardiac skeleton and heart valves seen from above. The 4 fibrous rings that surround the valves are known as the annulus fibrosus. The right fibrous trigone is the connective tissue bridge between the aortic valve and right atrioventricular (tricuspid) valve rings. The left fibrous trigone is the connective tissue bridge between the aortic valve and the left atrioventricular (mitral) valve rings. The yellow dot represents the atrioventricular bundle seen in cross section as it courses caudally from the atria to the ventricles. P.1:46

RADIOGRAPHY OF PROSTHETIC AORTIC AND MITRAL VALVES

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Diagnostic Imaging Cardiovascular

(Top) PA chest radiograph of a 56-year-old woman status post aortic and mitral valve replacement for rheumatic heart disease (Bjork-Shiley mechanical heart valves) shows the close relationship of the aortic and mitral valves and postsurgical changes. The aortic valve prosthesis is located in the center of the heart and is oriented along the long axis of the ascending aorta. The mitral valve prosthesis is located more inferiorly, and its orifice exhibits a more horizontal orientation. (Bottom) Left lateral chest radiograph (same patient) shows the aortic valve prosthesis in the center of the heart and the more posteriorly located mitral valve prosthesis oriented along the long axis of the left atrioventricular orifice. The close relationship of these 2 prosthetic valves is consistent with the fact that they share a common fibrous annulus and the left fibrous trigone. P.1:47

CT OF ATRIOVENTRICULAR VALVE

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(Top) Contrast-enhanced 2-chamber gated cardiac CT demonstrates the anterior and posterior leaflets of the mitral valve at the atrioventricular orifice. The posterior papillary muscle is also demonstrated. (Bottom) Normal contrastenhanced axial cardiac CT shows the mitral valve during ventricular filling (diastole). The valve cusps protrude into the ventricular lumen and are attached to the papillary muscles by thin chordae tendineae. P.1:48

ANATOMY AND MR OF SEMILUNAR VALVES

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Diagnostic Imaging Cardiovascular

(Top) Graphic illustrates the anatomy of the semilunar valves (the pulmonic and aortic valves). These valves are tricuspid (with 3 cusps) and have free edges without tendinous attachments to the ventricle. The free cusp edges project into the vessel lumen during valve closure, forming sinuses. Retrograde blood flow after ventricular contraction forces the valves shut. Antegrade blood flow during ventricular systole forces the valve open. The superior free edge of the valve cusp exhibits a central focus of nodular thickening (the nodule of the semilunar cusp) and a thin lateral free edge (the lunule of the semilunar cusp). (Bottom) Axial SSFP MR image shows a normal appearance of the aortic valve during systole. The aortic valve is composed of 3 cusps and corresponding sinuses of Valsalva. The noncoronary cusp can always be identified as it faces the interatrial septum. P.1:49

ANATOMY OF TRICUSPID AND PULMONIC VALVES

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Graphic illustrates the internal anatomy of the right ventricle and the anatomy of the right heart valves. The right atrioventricular valve is the tricuspid valve. It has 3 cusps that are attached to the fibrous valve ring and are continuous with each other at the valve commissures. The cusps are named according to their positions: Anterior, septal, and posterior. The free edges of the valves attach to chordae tendineae that, in turn, attach to the tips of papillary muscles that are also named according to their location. The pulmonic valve is a tricuspid semilunar valve located just distal to the right ventricular outflow tract. The free edges of the valve project into the pulmonary trunk, forming sinuses, and coapt at the nodules of the semilunar cusps. There are left, right, and anterior pulmonic valve cusps. P.1:50

CT OF RIGHT HEART VALVES

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Diagnostic Imaging Cardiovascular

(Top) Contrast-enhanced chest CT image demonstrates the anatomy and location of the right heart valves. The normal valves are thin and are difficult to visualize on conventional CT. Cardiac gated axial CT image shows the tricuspid valve imaged during ventricular systole. The coapted septal and anterior valve cusps manifest as thin soft tissue linear opacities within the contrast-filled right heart chambers. (Bottom) Oblique sagittal contrast-enhanced CT image through the pulmonary trunk (same patient) shows the anatomy and location of the pulmonic valve. The pulmonic valve is tricuspid and is located at the apex of the right ventricular outflow tract. This image is obtained during ventricular filling (diastole) and shows 2 of the 3 valve cusps coapted within the vessel lumen. The free valve edges protrude into the vascular lumen and form sinuses. P.1:51

ANATOMY OF LEFT HEART VALVES

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Graphic depicts the close relationship between the aortic and mitral valves. These valves are supported by fibrous valve rings connected by the left fibrous trigone. Thus, the anterior cusp of the mitral valve is closely related to the left coronary cusp of the aortic valve. The aortic valve right coronary, left coronary, and noncoronary cusps are shown. The semilunar cusps form sinuses during valve closure, which occurs by coaptation of the free cusp edges. Each valve has a fibrous nodule on the central portion of its free edge that is called the nodulus arantii. The mitral valve cusps are continuous along the left atrioventricular fibrous valve ring and are connected at the valve cusp commissures. The free edges of the mitral valve cusps attach to the anterior and posterior papillary muscles via chordae tendineae. P.1:52

ECHOCARDIOGRAPHY OF AORTIC AND MITRAL VALVES

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Diagnostic Imaging Cardiovascular

(Top) Three-chamber transthoracic echocardiography view in diastole shows left atrium, open mitral valve, left ventricle cavity, left ventricular outflow tract, and aortic root with a closed aortic valve. Note that the “3rd chamber” near the probe is the right ventricle and its outflow tract. (Middle) Transthoracic short-axis view of the closed aortic valve in diastole shows normal coaptation of all 3 cusps without regurgitant orifice. The cusps can be identified by the interatrial septum always pointing to the noncoronary cusp and by the right atrium, right ventricle, and right ventricular outflow tract “wrapping” around the right coronary cusp. (Bottom) Transthoracic short-axis view of the open aortic valve in systole shows unrestricted opening of the cusp and confirms that it has indeed an unobstructed tricuspid configuration. Fusion along cusp edges can lead to bicuspid or unicuspid configuration and obstruction. P.1:53

ANATOMY AND CT OF LEFT HEART VALVES

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(Top) Graphic illustrates a 3-chamber (left ventricular outflow tract) view of the heart and the relationship between the mitral and aortic valves. The fibrous rings that support these valves share a common fibrous bridge called the left fibrous trigone. The fibrous bridge forms a connection between the anterior cusp of the mitral valve and the left coronary cusp of the aortic valve. (Middle) Contrast-enhanced gated cardiac CT image demonstrates the anatomic relationship between the aortic and mitral valves. The left coronary cusp of the aortic valve shares a common fibrous attachment with the anterior cusp of the mitral valve. (Bottom) Four-chamber contrast-enhanced gated cardiac CT image demonstrates the close relationship between the anterior cusp of the mitral valve and the left coronary cusp of the aortic valve. The left coronary cusp is only partially visualized on this image. P.1:54

CT AND MR OF AORTIC VALVE

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(Top) Gated contrast-enhanced cardiac CT images demonstrate the cross-sectional imaging appearance of the aortic valve. Coronal image shows the aortic valve cusps in coaptation. The valve cusps manifest as thin curvilinear soft tissue structures located at the apex of the left ventricular outflow tract. The sinuses of Valsalva are located above the valve cusps and are visible during diastole. (Middle) Axial gated contrast-enhanced CT image through the aortic valve in coaptation shows right coronary, left coronary, and noncoronary sinuses of Valsalva bound by the aortic wall and the corresponding valve cusps. The noncoronary sinus of Valsalva always faces the interatrial septum. (Bottom) Axial SSFP MR image through the aortic valve in coaptation shows right coronary, left coronary, and noncoronary sinuses of Valsalva bound by the aortic wall and the corresponding valve cusps. P.1:55

CT OF MITRAL VALVE

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Diagnostic Imaging Cardiovascular

(Top) Contrast-enhanced 4-chamber gated cardiac CT demonstrates the anatomy of the mitral valve. The anterior and posterior valve cusps manifest as thin linear structures that extend across the atrioventricular orifice. While the trabeculated left ventricular wall is visible, the chordae tendineae are not visualized. (Bottom) Contrast-enhanced 2chamber gated cardiac CT demonstrates the anterior and posterior leaflets of the mitral valve at the atrioventricular orifice. The posterior papillary muscle is also demonstrated. P.1:56

MR, VALVE FUNCTION

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Diagnostic Imaging Cardiovascular

(Top) Gated cardiac SSFP MR image through the heart demonstrates the function of the heart valves. Four-chamber view obtained during ventricular systole shows that the atrioventricular valve cusps are coapted or closed, allowing blood to be pumped in an antegrade direction into the pulmonary and systemic arteries by the contracting myocardium without regurgitation or retrograde flow into the atria. (Bottom) Four-chamber gated cardiac SSFP MR image obtained during diastole (same patient) demonstrates that the cusps of the atrioventricular valves are open, allowing blood to flow in an antegrade direction from the atria to fill the bilateral ventricles. The papillary muscles where the chordae tendineae attach are also visualized. There are small bilateral pleural effusions, larger on the right. P.1:57

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(Top) Gated SSFP cardiac MR images demonstrate the function of the mitral and aortic valves. Three-chamber (left ventricular outflow tract) image obtained during ventricular systole demonstrates that the aortic valve cusps are not visible at the aortic root distal to the right ventricular outflow tract, indicating that the aortic valve is open to allow antegrade flow of blood into the aorta. The mitral valve cusps are closed or coapted to prevent regurgitation of ventricular blood into the left atrium. (Bottom) Three-chamber gated SSFP cardiac MR image obtained during diastole (same patient) shows that the mitral valve cusps are open to allow blood to flow into the left ventricle. The aortic valve cusps are closed, preventing retrograde flow of blood from the aorta. The papillary muscles of the left ventricle and moderator band of the right ventricle are also visualized.

Section 2 - Congenital Approach to Congenital Heart Disease Approach to Congenital Heart Disease Suhny Abbara, MD, FSCCT Christopher M. Walker, MD Introduction There are many different ways to approach congenital heart disease. A systematic approach is the segmental approach developed by Van Praagh more than 30 years ago. This approach uses three segments based on the cardiac embryologic development. Van Praagh used a notation system (three letters separated by commas) to easily convey the findings. The first step determines the visceroatrial situs. The second step identifies the morphologic right and left 73

Diagnostic Imaging Cardiovascular ventricles and their relationship to each other. The third step identifies the great vessels and their origin (ventriculoarterial connection). The final step involves a careful search for associated abnormalities of the septa, ventricular chambers, outflow tracts, veins, and great vessels. This approach allows the imager to dissect even the most complicated case into more manageable parts, which often leads to better interpretation. Van Praagh Segmental Approach First Step: Visceroatrial Situs Visceroatrial situs is determined by defining the relationship between the atria and thoracoabdominal organs. The left and right atria designations can be performed by identifying the shape of the atrial appendage. The left atrial appendage is a finger-like projection with a narrow orifice and pointed appearance whereas the right atrial appendage has a broad opening with a triangular shape. If it is difficult to designate an atrium as either left or right based on the shape of the atrial appendage, the rule of venoatrial concordance should be used. This rule states that the cardiac chamber receiving the inferior vena cava inflow from the liver is almost always the morphologic right atrium. Atrial configuration can also usually be inferred by the bronchial and pulmonary arterial anatomy, which is helpful when only radiographs are available. That is to say that the morphologic right atrium is generally on the side of the trilobed lung, and the morphologic left atrium is generally on the side of the bilobed lung. The morphologic right atrium receives the coronary sinus. After determining the atrial arrangement, one should next determine the position of the liver, spleen, and stomach to identify the type of situs. There are three types of situs. Situs solitus (S, -, -) is the normal configuration. In situs solitus, the right atrium and liver are on the right whereas the left atrium, spleen, and stomach are on the left. There is a normal trilobed right lung with early takeoff of the right upper lobe bronchus from the main bronchus and eparterial bronchial position (i.e., the right pulmonary artery travels immediately anterior to the right main bronchus). There is a bilobed left lung defined by a more distal origin of the left upper lobe bronchus with hyparterial bronchial position (i.e., the left pulmonary artery arches over the left main bronchus). Situs inversus (I, -, -) is the opposite of situs solitus. The left atrium, spleen, and stomach are on the right. The right atrium and liver are on the left. There is a trilobed left lung with eparterial bronchus and a bilobed right lung with hyparterial bronchus. Situs ambiguus (A, -, -), or heterotaxy, is present when the situs is neither solitus nor inversus. There are two generally described subsets of situs ambiguus: Bilateral right-sidedness (asplenia syndrome, right isomerism) and bilateral leftsidedness (polysplenia syndrome, left isomerism). Patients with asplenia syndrome generally have bilateral trilobed lungs, a horizontal position to the liver, splenic agnesis, and severe congenital heart disease. In contrast, patients with polysplenia syndrome have bilateral bilobed lungs, multiple small splenules, interruption of the inferior vena cava with azygos or hemiazygos continuation, and less severe congenital heart disease (e.g., atrial septal defect or ventricular septal defect). After determining visceroatrial situs, it is important to describe the position of the heart in the thorax and the orientation of the cardiac apex as patients with discordant situs and heart position generally harbor more severe congenital heart disease. Three different terms describe the location of the heart in the thorax: Levoposition (heart within the left thorax), dextroposition (heart within the right thorax), and mesoposition (midline position of the heart). It is important to note that specific lung abnormalities (e.g., hypoplasia) may cause cardiac rotation. Second Step: Ventricular Loop Orientation The cardiac loop is defined by the rotation of the right ventricle: D-loop (-, D, -) indicates rotation of the right ventricle to the right, and L-loop (-, L, -) indicates rotation of the right ventricle to the left. The anatomic rotation normally is Dloop. In order to determine the loop orientation, first identify the morphologic right and left ventricles. The morphologic right ventricle has several distinguishing features, including a muscular infundibulum separating the atrioventricular and ventriculoarterial valves, an atrioventricular septal leaflet closer to the ventricular apex, a moderator band, interventricular septal trabeculation, and papillary muscles that attach to both the septum and the free wall. On the other hand, the morphologic left ventricle demonstrates fibrous continuity of the atrioventricular and ventriculoarterial valves, a smooth interventricular septum, and papillary muscles that attach only to the free wall. Occasionally, it might be difficult to decide which ventricle is the morphologic left ventricle and which is the morphologic right ventricle. In this setting, the loop rule can be used. The loop rule states that the rotation is D-loop (i.e., the right ventricle is to the right of the left ventricle) in the presence of a right-sided aortic valve, and the rotation is L-loop (i.e., the right ventricle is to the left of the left ventricle) in the presence of a left-sided aortic valve. Third Step: Identification of the Position and Origin of Great Vessels The position of the great vessels is most easily assessed at a level superior to the aortic and pulmonic valves. Normally, the main pulmonary artery is located anterior to and to the left of the aorta, which is termed the solitus configuration (-, -, S). In situs inversus (-, -, I), the main pulmonary artery is located anterior to and to the right of the aorta. Four other configurations of the great vessels may be seen: D-transposition (-, -, D-TGA), L-transposition (-, -, LTGA), D-malposition (-, -, D-MGA), and L-malposition (-, -, L-MGA).

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Diagnostic Imaging Cardiovascular In D-transposition, the aorta is located anterior to and to the right of the main pulmonary artery. The aorta originates from the morphologic right ventricle, and the P.2:3 pulmonary artery originates from the morphologic left ventricle. In L-transposition, the aorta is located anterior to and to the left of the main pulmonary artery. The aorta originates from the morphologic right ventricle, and the pulmonary artery originates from the morphologic left ventricle. In contrast to D-transposition, there is also atrioventricular discordance (i.e., the ventricular loop has an L-orientation). This creates a situation that has been termed “congenitally corrected transposition” as oxygenated blood still flows to the systemic circulation and deoxygenated blood still flows to the lungs. Two other configurations occur in the setting of a double outlet ventricle and are diagnosed when the great vessels are parallel to each other and originate from a single ventricle. These configurations have been termed malpositions. The final situation, truncus arteriosus, occurs when a single great vessel arises from both ventricles. Atrioventricular Connection There are generally five types of connections that have been described between the atria and ventricles: Concordant, discordant, ambiguous, double inlet, or absent. In concordant connection (normal), the left atrium connects to the left ventricle and the right atrium connects to the right ventricle. In discordant connection (e.g., L-transposition), the right atrium connects to the left ventricle whereas the left atrium connects to the right ventricle. An ambiguous connection occurs in the setting of heterotaxy syndrome (i.e., asplenia or polysplenia). An absent connection occurs with valve atresia. Associated Malformations It is important to search for associated malformations that are not addressed in the segmental approach described above as they often significantly influence the surgical approach and techniques used to correct the congenital heart disease. A systematic approach should be used to avoid satisfaction of search. Start at the level of the heart, and document the size and type of atrial or ventricular septal defects and their effect on ventricular size and function. Search for outflow tract stenoses, and document the degree of narrowing. Evaluate the aorta and pulmonary artery to exclude hypoplasia, interruption, stenosis, coarctation, and patent ductus arteriosus. Next, evaluate systemic and pulmonary venous drainage. You should document the presence of a left superior vena cava and the presence or absence of a connection with a right superior vena cava and the drainage pattern of the left superior vena cava. In the majority of patients (about 90%), the left superior vena cava drains into the right atrium via an enlarged coronary sinus. In 10% of patients, there is an unroofed coronary sinus, and the vein drains abnormally into the left atrium. Look for an interrupted inferior vena cava with azygos or hemiazygos continuation. Finally, identify all pulmonary veins and whether or not they drain normally into the left atrium. Footsteps of the Surgeon It is important for the imager to be familiar not only with the preoperative anatomy of patients with congenital heart disease but also with the appearance following surgical correction. As patients with congenital heart disease survive into the fourth and fifth decades of life, all imagers who interpret cross-sectional imaging should have a basic understanding of the surgeries used and the physiology that results. Knowledge of postoperative anatomy and physiology allows accurate detection of complications that may follow the various surgical procedures. There are also situations in which the surgical procedure is unknown and the imager will be relied on to identify the operation that was performed. A detailed description of all palliative and corrective surgical procedures used in the treatment of congenital heart disease and their known complications is beyond the scope of this introductory chapter. Rather, we will briefly describe the most current and common procedures that will be encountered in clinical practice and the goals of surgery. We will first describe palliative procedures used in the treatment of congenital heart disease, followed by several definitive repairs. Palliative Procedures The modified Blalock-Taussig shunt is a palliative procedure used to augment pulmonary blood flow to decrease cyanosis prior to definitive repair. A synthetic graft is interposed between the subclavian artery and right or left main pulmonary artery. The most common complication of the Blalock-Taussig shunt is thrombosis, which usually occurs months to years following shunt creation. The Blalock-Taussig shunt is typically taken down or ligated at the time of definitive repair. Pulmonary arterial banding is a palliative procedure in which the main pulmonary artery is encircled with synthetic material with the goal of decreasing pulmonary blood flow. This protects the distal pulmonary circulation from excessive blood flow and high pressures. Pulmonary arterial banding is also used to train the left ventricle in the setting of transposition of the great arteries (TGA) without ventricular septal defect prior to a definitive Jatene arterial switch procedure. If the arterial switch procedure is performed without pulmonary arterial banding, the left ventricle

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Diagnostic Imaging Cardiovascular will often fail as it has not been exposed to pressures required to pump blood systemically. The major complication of pulmonary arterial banding is proximal pulmonary arterial dilation with resultant pulmonic valve insufficiency. Definitive Surgeries The bidirectional Glenn shunt is used to augment pulmonary blood flow in the setting of right-sided heart hypoplasia or atresia (e.g., tricuspid atresia, hypoplastic right heart, Ebstein anomaly). It is also a part of the definitive repair for hypoplastic left heart syndrome. The superior vena cava is removed from the right atrium and is connected to the right pulmonary artery, which allows deoxygenated blood from the upper extremity to bypass the heart and directly enter both lungs. The procedure requires a low-pressure system to perfuse the lungs and thus must be performed after pulmonary vascular resistance drops (i.e., about 3-9 months following birth). The bidirectional Glenn shunt is usually followed by a Fontan procedure, which routes deoxygenated blood from the lower extremity around the right heart directly to the pulmonary arteries. The Fontan procedure uses prosthetic material to create a tunnel from the inferior vena cava to the right pulmonary artery either around (conduit) or through (baffle) the right atrium. The major complications that can be detected by imaging include shunt thrombosis or new pulmonary arteriovenous malformations or venovenous collaterals. P.2:4

The Norwood procedure is a three-stage surgery used in patients with hypoplastic left heart syndrome. The goals of the surgery are to convert the right ventricle into the systemic pumping chamber, create unobstructed systemic venous blood flow to the lungs, and divert pulmonary venous return to the right atrium. Stage one is performed shortly after birth and uses the main pulmonary artery to reconstruct the hypoplastic aorta. The atrial septum is excised to create a single atrium and allow oxygenated pulmonary venous return to pass into the right ventricle. Finally, the pulmonary blood flow is reestablished by a modified Blalock-Taussig or Sano shunt (i.e., conduit from the right ventricle to the pulmonary artery). Stage two is performed when pulmonary vascular resistance drops. The goal is to begin separating the pulmonary and systemic vasculature. The previously placed modified Blalock-Taussig shunt is ligated, and a bidirectional Glenn shunt is implemented to divert systemic venous return from the upper extremity to the lungs. During stage three, the Fontan procedure is performed to completely separate the systemic and pulmonary circulations. Surgical repair of transposition of the great arteries has evolved over the years. The initial treatment involved diverting blood flow by the use of intra-atrial baffles (i.e., a pathway made by patient tissue and synthetic graft). The Mustard and Senning procedures were the initial intra-atrial baffles that diverted systemic venous blood to the left ventricle and oxygenated pulmonary venous blood to the systemic-pumping right ventricle. The major complication of these procedures is a baffle stenosis, obstruction, or leak. The intra-atrial baffle procedures have largely been replaced by the Jatene arterial switch procedure with Lecompte maneuver as the right ventricle was not designed to be the systemic pumping chamber. In this latter procedure, the aorta and pulmonary arteries are switched and reanastomosed to their respective ventricles. The Lecompte maneuver places the main pulmonary artery anterior to the aorta to reduce the risk of coronary artery compression. The most common complications seen in the Jatene procedure are late pulmonary stenosis at the anastomosis, aortic enlargement, and coronary artery occlusion or stenosis. Aortic coarctation can be repaired either surgically or percutaneously (stenting and/or angioplasty). The surgical techniques used include direct excision of the coarctation with end-to-end anastomosis, patch aortoplasty with prosthetic material or native subclavian artery patch plasty, and bypass grafts. The major complications associated with surgical repair include recurrent coarctation, aneurysm formation, and impaired growth of the left upper extremity in the setting of subclavian artery patch repair. Endovascular balloon angioplasty and stent placement are used in the setting of recurrent and occasionally native coarctation. The major complications include aneurysm formation at the site of angioplasty, aortic dissection, and aortic rupture. Stenting is usually avoided in small children as the aorta has not yet reached its final size. Septal defects can be repaired surgically by direct closure or with patch augmentation or occluded percutaneously with a prosthetic device in the setting of a secundum type of atrial septal defect. A patent ductus arteriosus is managed medically (with prostaglandin inhibitors), surgically (with ligation), or percutaneously (with coil or occluder device embolization). The main goals of therapy in patients with tetralogy of Fallot include closing the ventricular septal defect and relieving right ventricular outflow tract obstruction. Currently, a ventricular septal defect is closed through a transatrial approach in order to avoid a large ventricular incision. A transannular patch is placed at the time of ventricular septal defect repair to augment the diameter of the right ventricular outflow tract and relieve the obstruction. The major complication associated with tetralogy of Fallot repair is pulmonic regurgitation. The right ventricle responds to valve regurgitation by dilating. At first, the response is adaptive and improves right ventricular output; over time, however, the right ventricle decompensates.

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Diagnostic Imaging Cardiovascular MR is used extensively in patients with tetralogy of Fallot to document the degree of right ventricular dilation and pulmonic regurgitation to allow the surgeon and cardiologist to appropriately time pulmonic valve replacement. MR is also useful in identifying recurrent right ventricular outflow tract narrowing or branch pulmonary artery stenosis. A special situation exists in patients with tetralogy of Fallot and pulmonary atresia. Definitive surgical repair is performed in the neonatal period and involves closure of the ventricular septal defect through a right ventricular incision. Subsequently, a valved conduit is placed between the right ventricle and main pulmonary artery. The conduit is replaced as patients age. Selected References 1. Lu JC et al: Evaluation with cardiovascular MR imaging of baffles and conduits used in palliation or repair of congenital heart disease. Radiographics. 32(3):E107-27, 2012 2. Babar JL et al: Application of MR imaging in assessment and follow-up of congenital heart disease in adults. Radiographics. 30(4):1145, 2010 3. Lapierre C et al: Segmental approach to imaging of congenital heart disease. Radiographics. 30(2):397-411, 2010 4. Gaca AM et al: Repair of congenital heart disease: a primer—part 1. Radiology. 247(3):617-31, 2008 5. Gaca AM et al: Repair of congenital heart disease: a primer—part 2. Radiology. 248(1):44-60, 2008 6. Van Praagh R: The importance of segmental situs in the diagnosis of congenital heart disease. Semin Roentgenol. 20(3):254-71, 1985 7. Van Praagh R: Diagnosis of complex congenital heart disease: morphologic-anatomic method and terminology. Cardiovasc Intervent Radiol. 7(3-4):115-20, 1984 8. Van Praagh R et al: Dextrocardia, mesocardia, and levocardia: the segmental approach to diagnosis in congenital heart disease. In Keith JD et al: Heart Disease in Infancy and Childhood. 3rd ed. New York: Macmillan. 638-95,1978 9. Van Praagh R: Terminology of congenital heart disease. Glossary and commentary. Circulation. 56(2):139-43, 1977 10. Van Praagh R: The segmental approach to diagnosis in congenital heart disease. In Bergsma D: Birth Defects: Original Article Series. Vol. 8, no. 5. The National Foundation—March of Dimes. Baltimore: Williams & Wilkins. 4-23, 1972 P.2:5

Image Gallery

(Left) Coronal CECT shows normal bronchial anatomy in situs solitus. The right main bronchus is short with early takeoff of the right upper lobe bronchus . The left main bronchus is long with late takeoff of the upper lobe bronchus . (Right) Composite image shows that the right atrial appendage (left panel) has a broad opening and triangular shape. The left atrial appendage (right panel) is characterized by a finger-like projection with a narrow orifice.

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(Left) Coronal CECT shows situs inversus, lower lobe bronchiectasis, and tree-in-bud nodules in a patient with Kartagener syndrome. The right bronchus has a late takeoff of the upper lobe bronchi, which is more typical of the left lung, whereas the left bronchus has an early takeoff of the upper lobe bronchus, which is more typical of the right lung. (Right) Composite image from the same patient shows a right descending thoracic aorta, right-sided spleen, and left-sided liver.

(Left) Coronal CTA shows abnormally symmetric short mainstem bronchi with an early takeoff of the upper lobe bronchi bilaterally. Note that neither bronchus has a pulmonary artery arching over it (bilateral eparterial bronchi), indicating right isomerism/asplenia. (Right) 3D reconstruction of multidetector CT tracheobronchial tree shows symmetric long mainstem bronchi with late takeoff of the upper lobe bronchi bilaterally, indicating bilateral leftsidedness or left isomerism. P.2:6

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(Left) Left ventricular outflow tract (3-chamber) view CTA shows fibrous continuity (connection) of the aortic valve and the mitral valve , which is a key feature for identification of the morphologic left ventricle (LV). Aorta= Ao; left atrium = LA. (Right) Short-axis CTA at the midventricular level shows 2 papillary muscles attaching to the left ventricular free wall. No papillary muscles attach to the interventricular septum in the morphologic left ventricle.

(Left) Oblique coronal CECT shows a muscular infundibulum separating the pulmonic valve from the tricuspid valve , which is a key feature of the morphologic right ventricle (RV). Right atrium = RA; main pulmonary artery = PA; aorta = Ao. (Right) Graphic shows the positions of the aortic and pulmonary valves and arteries in the settings of solitus configuration, situs inversus totalis, D-TGA, and L-TGA. Solitus configuration is the orientation seen in the majority of the population.

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(Left) Axial CECT shows multiple spleens in a patient with left isomerism and polysplenia . The patient also had bilateral hyparterial bronchi and left lungs (not shown). (Right) Axial CTA shows a moderator band originating from the interventricular septum, and this feature identifies the ventricle as the morphologic right ventricle. The cardiac loop is “L” in this case because the right ventricle is to the left of the left ventricle. P.2:7

(Left) Composite image shows the relationship of the aorta (Ao) and main pulmonary artery (PA) in a solitus configuration (left panel) and in an inversus configuration (right panel). In solitus, the aorta is located posterior and to the right of the pulmonary artery. In inversus, the aorta is located posterior and to the left of the pulmonary artery. (Right) Four chamber view CTA shows a large atrial septal defect . There is dilation of the right atrium and right ventricle from a chronic left-to-right shunt.

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(Left) Composite image shows the relationship of the aorta (Ao) and main pulmonary artery (PA) in a D-transposition configuration (left panel) and in an L-transposition configuration (right panel). In D-TGA, the aorta is located anterior and to the right of the pulmonary artery. In L-TGA, the aorta is located anterior and to the left of the pulmonary artery. (Right) Oblique MRA shows a large patent ductus arteriosus connecting the aorta (Ao) to the main pulmonary artery (PA).

(Left) Axial CECT shows a small membranous ventricular septal defect . It is important to search for associated malformations that are not addressed in the segmental approach, as they often significantly influence patient prognosis and management. (Right) Axial oblique image from an MRA shows the classic findings of a Jatene arterial switch with the pulmonary artery lying anterior to the aorta , and the left and right pulmonary arteries draping over the aorta. P.2:8

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(Left) Coronal MRA in a patient with tricuspid atresia shows the superior vena cava draining directly into the right pulmonary artery (bidirectional Glenn shunt). (Right) 3D MRA image from the same patient shows the inferior vena cava draining directly into the right pulmonary artery (Fontan shunt). The bidirectional Glenn and Fontan shunts are used in the setting of right-sided heart lesions (e.g., tricuspid atresia, hypoplastic heart, and Ebstein anomaly).

(Left) 3D volume-rendered MRA image in a patient with double inlet left ventricle shows extracardiac Fontan conduit and bidirectional Glenn connecting to the right pulmonary artery. (Right) Lateral radiograph shows an Amplatzer occluder device used to close an atrial septal defect. The device is usually easier to see on the lateral chest radiograph because it overlies the spine on the frontal view. Also seen is the stent at the coarctation site .

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(Left) Axial CTA in a patient with hypoplastic left heart syndrome and Norwood procedure shows a single large neoaorta arising from the right ventricle. The neoaorta is created by utilizing the main pulmonary artery to reconstruct the hypoplastic ascending aorta and aortic arch. (Right) Axial CTA in the same patient shows marked right ventricular hypertrophy and a hypoplastic rudimentary left ventricle . Note unopacified blood in the extracardiac Fontan conduit . P.2:9

(Left) Frontal radiograph in a patient with D-TGA and prior intra-atrial baffle (Senning procedure) shows a dualchamber pacemaker with leads crossing through the baffle to terminate in the left atrium and left ventricle (Right) Lateral radiograph in the same patient shows pacemaker leads terminating posteriorly in the left atrium and in the morphological left ventricle , respectively.

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(Left) Frontal radiograph shows a patent ductus arteriosus ligation clip . This procedure can be performed by a thoracotomy or video-assisted thorascopic surgery. (Right) Cine right ventricular outflow tract SSFP MR image in a patient with repaired tetralogy of Fallot shows a spin-dephasing flow-void artifact of pulmonic regurgitation. MR is used to follow the degree of right ventricular dysfunction and pulmonic regurgitation in order to appropriately time valve replacement.

(Left) Oblique sagittal CTA shows mild narrowing of the proximal aspect of the descending thoracic aorta from previous aortic coarctation repair. Note the elongated arch as indicated by the increased distance between the left common carotid and subclavian arteries. (Right) Sagittal oblique 3D reconstruction from a CTA shows a dilated ascending aorta and aneurysm at the level of a previous coarctation repair .

Coarctation of Aorta Coarctation of Aorta Santiago Martínez-Jiménez, MD Key Facts Terminology  Congenital narrowing of aorta, most commonly occurring just distal to left subclavian artery origin Imaging  Chest radiograph: Inferior rib notching, “figure 3” sign  Esophagram: “Reverse figure 3” sign  CTA: Focal shelf-like narrowing of posterior/lateral aorta just distal to left subclavian origin  MR o Contrast-enhanced 3D MRA for vessel morphology and depiction of enlarged collateral arteries 84

Diagnostic Imaging Cardiovascular o Velocity-encoded cine is used to estimate pressure gradients and flow volumes Angiography o Morphology of coarctation and collateral vessels o Measurement of pressure gradients Top Differential Diagnoses  Pseudocoarctation  Takayasu arteritis Pathology  Associations o Bicuspid aortic valve, ventricular septal defect, patent ductus arteriosus o Turner syndrome Clinical Issues  Surgical correction used for infants  Balloon angioplasty used for children and adults  Stent placement typically for recoarctation Diagnostic Checklist  Search for subtle signs of coarctation in any young patient with hypertension 

(Left) PA radiograph of the chest demonstrates the classic “figure 3” morphology in a patient with aortic coarctation. Note the area of stenosis , dilated subclavian artery , and poststenotic dilatation . (Right) Lateral radiograph of the chest in the same patient reveals an indentation along the aortic isthmus representing the stenosis. While the “figure 3” sign is not frequently seen, its presence suggests the diagnosis and should prompt additional evaluation.

(Left) Axial CTA of the aorta shows a classic coarctation

. Note relatively normal caliber of the aorta proximal and 85

Diagnostic Imaging Cardiovascular distal to the critical stenosis. There are extensive mediastinal collaterals seen as serpiginous vessels around the coarctation and dilated internal mammary arteries, which also reflects collateral flow. (Right) Oblique CTA 3D reformation in the same patient shows the coarctation . Note the intercostal arteries , which appear dilated due to collateralization. P.2:11

TERMINOLOGY Definitions  Congenital narrowing of aorta, most commonly occurring just distal to left subclavian artery origin  Atypical coarctation: Not involving isthmus (usually abdominal aorta) IMAGING Radiographic Findings  Radiography o Inferior rib notching (Roesler sign)  Related to enlargement of intercostal arteries serving as collaterals  Rare before 5 years of age  Affects ribs 3-8; ribs 1 and 2 are not affected, as they arise from costocervical trunk and do not anastomose with distal aorta o “Figure 3” sign in up to 50% of cases  Dilated left subclavian artery produces proximal convexity  Indentation at coarctation  Poststenotic descending aorta produces distal convexity o Ill-defined or obscured aortic arch o Mediastinal widening CT Findings  CTA o Excellent morphologic characterization  Defines location and severity of stenosis  Focal shelf-like narrowing of posterior/lateral aorta just distal to left subclavian origin  Enlarged collateral arteries indicate hemodynamic significant obstruction at coarctation site o Gradient cannot be calculated MR Findings  Allows morphologic and functional assessment  Morphology o Achieved with several MR protocols: HASTE, SSFP (TrueFISP, FIESTA), contrast-enhanced MR angiography (MRA) o HASTE (dark blood) and SSFP (bright blood) o “Gothic” or angulated aortic morphology after coarctation surgery is associated with high risk of arterial hypertension o Useful to assess for complications: Aneurysm, pseudoaneurysm, recoarctation o Contrast-enhanced MRA  Planimetry: Determine orthogonal diameters and areas from proximal to distal to the ductus  Indexed minimal aortic cross-sectional area (cm2/m2)  Best predictor of severity  < 0.33 cm2/m2 indicates severe coarctation (gradient ≥ 20 mm Hg)  Demonstrates enlarged collateral arteries  Velocity-encoded cine MR o Heart rate-corrected deceleration time (cm-0.5)  Adjusted to heart rate  Deceleration time = [(flow at end of deceleration) - (peak systolic flow)]/(deceleration time)  Excellent predictor of severity  ≥ 0.30 cm-0.5 indicates severe coarctation (gradient ≥ 20 mm Hg) o Amount of collateral flow  Percent increase in flow between aorta immediately distal to coarctation and just above diaphragmatic crura due to collateral flow  Normal subjects: 7% ± 6% decrease 86

Diagnostic Imaging Cardiovascular  Coarctation (gradient < 20 mm Hg): No increase  Coarctation (gradient ≥ 20 mm Hg): 83% ± 50% mean increase o May be used to quantify aortic valve stenosis and regurgitation  Combination of indexed minimal cross-sectional area and heart rate-corrected deceleration time best predicts hemodynamically significant coarctation  Cine MR o Gold standard to assess left ventricular hypertrophy (myocardial thickness and mass) o Enables characterization of bicuspid aortic valve Angiographic Findings  Vessel morphology and direct measurement of pressure gradient o < 20 mm Hg: Mild coarctation o ≥ 20 mm Hg: Suggests need for intervention Imaging Recommendations  Best imaging tool o MR and MRA often fully characterize and determine needs of treatment o Angiography remains gold standard; used when MR is inconclusive DIFFERENTIAL DIAGNOSIS Pseudocoarctation  Older adult with elongation and kinking of aorta related to atherosclerosis  No hemodynamically significant stenosis  No collateral vessels Takayasu Arteritis  Inflammatory narrowing of unknown etiology  Narrowing &/or occlusion of aorta and branch vessels, rarely isolated to aortic isthmus Interrupted Aortic Arch  Complete absence of continuity between 2 segments of aorta  Nearly always manifests in neonates Traumatic Pseudoaneurysm  History of trauma, healed rib, and other skeletal fractures  Narrowing of descending thoracic aorta may coexist with pseudoaneurysm Inferior Rib Notching Differential  Neurofibromatosis  Venous collaterals (superior vena cava obstruction)  Decreased pulmonary blood flow (tetralogy of Fallot, pulmonary atresia)  Blalock-Taussig shunt (ribs 1 and 2) P.2:12

PATHOLOGY General Features  Etiology o Muscular theory  Migration of tissue from ductus arteriosus into aortic wall and subsequent contraction o Hemodynamic theory  Decreased aortic blood flow during fetal development may not allow proper aortic growth  Increased incidence of coarctation in disorders in which left ventricular outflow tract obstruction reduces aortic blood flow  Decreased incidence of coarctation in disorders in which decreased ductal flow is present (e.g., tetralogy of Fallot)  Associated abnormalities o Bicuspid aortic valve (reported in 50-85%) o Ventricular septal defect o Patent ductus arteriosus o Cerebral aneurysms o Variable evidence regarding increased risk of coronary artery disease Staging, Grading, & Classification  No agreed-upon classification

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Previously used classifications, including infantile and adult types, are discouraged due to overlapping manifestations  Pathophysiological classification o Preductal o Ductal o Post ductal  Simple coarctation o Occurs in isolation  Complex coarctation o Occurs in presence of other intracardiac anomalies; thus, tends to manifest in infancy o Often preductal Gross Pathologic & Surgical Features  Obstructing membrane or ridge of tissue near aortic isthmus  May develop cystic medial necrosis adjacent to coarctation site; predisposes to aneurysm or dissection CLINICAL ISSUES Presentation  Most common signs/symptoms o Presentation depends on degree of stenosis and associated abnormalities o Neonates  Asymptomatic if coarctation not severe or patent ductus arteriosus  If severe coarctation or closed ductus arteriosus, may have heart failure  Decreased femoral pulses, associated murmurs o Children and adults  May be asymptomatic  Leg claudication  Differential blood pressure between upper and lower extremities, diminished femoral pulses  Angina pectoris  Severe hypertension  Murmur associated with bicuspid aortic valve  Other signs/symptoms o Turner syndrome: Short webbed neck, broad chest, pigmented facial nevi, short 4th metacarpals Demographics  Gender o M:F = 2:1  Ethnicity o White:Asian = 7:1  Epidemiology o Incidence: 2-6 per 10,000 births o Comprises 5-10% of cases of congenital heart disease Natural History & Prognosis  Without repair o 75% mortality rate by age 46  With repair o ˜ 90% survival rate at 20 years; decreased chance of survival with increased age at repair o Recoarctation (2-14%) o Postoperative aneurysms (increased risk after patch aortoplasty) o Long-term survival rate decreased due to hypertension, coronary artery disease, dissection  Pregnancy-related issues o Untreated coarctation: Increased risk of dissection and intracranial hemorrhage o Treated coarctation: Increased rate of miscarriage and preeclampsia Treatment  Indications for treatment o Infant with severe stenosis and heart failure o Longstanding hypertension o Hemodynamically significant stenosis (gradient > 20 mm Hg) o Extensive collateral flow o Female patient contemplating pregnancy 88

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Surgical correction: First-line treatment for infants Balloon angioplasty o First-line treatment for older children and adults for native coarctation or recoarctation  Stent placement DIAGNOSTIC CHECKLIST Consider  Search for subtle signs of coarctation in any young patient with hypertension Image Interpretation Pearls  Enlarged collaterals imply significant stenosis SELECTED REFERENCES 1. Muzzarelli S et al: Usefulness of cardiovascular magnetic resonance imaging to predict the need for intervention in patients with coarctation of the aorta. Am J Cardiol. 109(6):861-5, 2012 2. Kimura-Hayama ET et al: Uncommon congenital and acquired aortic diseases: role of multidetector CT angiography. Radiographics. 30(1):79-98, 2010 3. Hom JJ et al: Velocity-encoded cine MR imaging in aortic coarctation: functional assessment of hemodynamic events. Radiographics. 28(2):407-16, 2008 P.2:13

Image Gallery

(Left) PA chest radiographs in 2 different patients with aortic coarctation show an ill-defined mediastinal widening on the left and mediastinal contour abnormality on the right. Visualization of the classic “figure 3” sign is often obscured by the presence of mediastinal collaterals. (Right) PA chest radiograph shows an inferior rib notching , the socalled Roesler sign, a classic radiographic sign of aortic coarctation produced by dilation of collateral vasculature. (Courtesy L. Heyneman, MD.)

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(Left) Axial CTA images at the prestenotic level (left) and the coarctation site (right) show characteristic focal narrowing due to the coarctation and dilated internal mammary and intercostal arteries that serve as collateral pathways. (Right) Oblique CTA MIP reformation in the same patient better delineates the coarctation , poststenotic dilatation of the descending thoracic aorta, tortuous and dilated internal mammary artery , and intercostal collateral arteries .

(Left) Volume-rendered 3D CTA of a patient with aortic coarctation allows for morphologic assessment of the coarctation and provides an overall appreciation of the extent of collateralization. 3D reformations are most helpful for clinicians/surgeons to get a gestalt of the 3D configuration of the pathology. (Right) DSA of a patient undergoing angiography for subarachnoid hemorrhage shows the catheter tip proximal to an incidentally detected tight aortic coarctation. P.2:14

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(Left) Short-axis SSFP MR through the aortic valve shows a bicuspid aortic valve in a patient with aortic coarctation. Note that the aortic valve has only 2 cusps . This is a common association in patients with aortic coarctation. (Right) Axial SSFP MR images through the area of aortic coarctation show an ascending aorta normal in diameter, a diminutive proximal descending aorta in the area of coarctation , and a relatively normal diameter of the more distal descending aorta .

(Left) Sagittal SSFP MR images in a patient with aortic coarctation show a well-defined long-segment area of stenosis in the the proximal descending aorta . (Right) Oblique aortic MRA MIP reformation in the same patient shows marked stenosis with extensive regional collaterals resulting from a hemodynamically significant obstruction. MRA is useful for determining the minimal aortic cross-sectional area (as is CT).

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(Left) Frontal radiograph of the chest in a patient with aortic coarctation. Note that despite cardiomegaly, the mediastinum does not appear widened but rather has ill-defined borders. Often, the radiographic findings are nonspecific. In this case, the hazy mediastinal borders are due to mediastinal collaterals. (Right) Oblique sagittal SSFP MR in the same patient demonstrates a marked stenosis of the proximal descending aorta in keeping with the coarctation. P.2:15

(Left) Short-axis SSFP cine MR in this patient with coarctation shows concentric thickening of the left ventricular myocardium, consistent with left ventricular hypertrophy. This is a sequelae from longstanding upper body arterial hypertension. (Right) Anterior and posterior MIP views of sagittal aortic MRA demonstrate coarctation and extensive chest wall and mediastinal collaterals. Collateral vessels are better characterized when thin-slice images (e.g., MRA) are reformatted to MIPs.

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(Left) This axial phase-contrast MR is from a patient with Shone complex that includes coarctation. While this sequence does not provide good morphologic correlation, it allows calculation of flow velocities and volumes over time, which may be used to quantify heart rate-corrected deceleration time. (Right) 3D volume-rendered MRA (same patient) shows coarctation with poststenotic dilatation. Shone complex includes coarctation, supravalvular mitral ring, parachute mitral valve, and subaortic stenosis.

(Left) This oblique sagittal CTA of the aorta is from a patient with coarctation who underwent successful endovascular stent placement after a failed treatment with angioplasty. CT and MR allow for follow-up and assessment of stent complications. (Right) Oblique sagittal CTA in a patient with remote history of surgically corrected aortic coarctation shows aneurysmatic dilatation of the left subclavian artery and the proximal descending aorta , a known complication after this type of surgery.

Double Aortic Arch Double Aortic Arch Santiago Martínez-Jiménez, MD Key Facts Terminology  Right and left aortic arches  Variants o Both arches patent and functioning o Right arch patent, left arch atretic Imaging  Radiography 93

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Frontal projection: Bilateral paratracheal nodular opacities, bilateral distal tracheal bilateral indentations Lateral projection: Posterior tracheal indentation of mid trachea

CTA o o

Right aortic arch: Right dominant, more cephalad 4-artery sign: Symmetric take-off of 4 aortic branches on axial image at thoracic inlet (2 ventral carotids and 2 dorsal subclavians) Top Differential Diagnoses  Right aortic arch with aberrant left subclavian artery and Kommerell diverticulum  Right aortic arch with mirror-image branching and aortic diverticulum  Left pulmonary artery sling  Mediastinal mass Pathology  20% associated with congenital heart disease Clinical Issues  Children o Dyspnea, often during during feeding  Adults o May be asymptomatic o Esophageal obstruction (i.e., dysphagia)  Treatment: Surgical division of smaller or atretic aortic arch and ligamentum arteriosus

(Left) Graphic shows a double aortic arch with a complete vascular ring encircling and compressing the trachea and esophagus. (Right) Sagittal 3D reformation of chest CTA shows a patent right aortic arch and smaller left aortic arch . There are 4 major branches (2 ventral carotids and 2 dorsal subclavian arteries), each set arising form each aortic arch. This is known as the 4-artery sign. The trachea and esophagus (not shown) are completely surrounded by the vascular ring.

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(Left) PA chest radiograph in a presurgical asymptomatic woman shows a right aortic arch larger than the left , with narrowing of the distal trachea affecting the right margin more severely. Typically, the right arch tends to be larger. The left arch is often smaller, hypoplastic, or atretic. (Right) Lateral chest radiograph in the same patient shows an indentation of the posterior margin of the distal trachea due to the larger right aortic arch . P.2:17

TERMINOLOGY Abbreviations  Double aortic arch (DAA) Definitions  Right and left aortic arches IMAGING General Features  Best diagnostic clue o Bilateral paratracheal opacities with concentric mid tracheal narrowing Radiographic Findings  Radiography o Frontal projection  Bilateral paratracheal opacities  Bilateral tracheal indentations o Lateral  Posterior tracheal indentation Fluoroscopic Findings  Esophagram o Frontal projection  S-shaped bilateral indentations on contrast-filled esophagus, right higher and larger than left o Lateral view  Large posterior indentation, often oblique CT Findings  CTA o Right aortic arch  Larger in most patients (right dominant)  More cephalad than left  Courses behind esophagus o Left aortic arch  Often smaller than right aortic arch o 4-artery sign: Symmetric take-off of 4 aortic branches on axial image at thoracic inlet (2 ventral carotids and 2 dorsal subclavians) o 1 descending aorta, usually left-sided 95

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Airway CT o Inspiration and expiration CT may help differentiate malacia from stenosis o Tracheomalacia: Tracheal collapse adjacent to vascular ring during expiration o Bronchomalacia: Left main bronchus collapse adjacent to midline descending aorta during expiration MR Findings  As accurate as CT in assessing vascular anatomy and tracheal stenosis  Of value in young individuals due to lack of ionizing radiation Imaging Recommendations  Best imaging tool o MR and CT are equally accurate in assessing vascular and tracheal anatomy  Protocol advice o Multiplanar reformations are helpful in delineating arch anatomy and tracheal abnormalities DIFFERENTIAL DIAGNOSIS Right Aortic Arch With Aberrant Left Subclavian Artery and Kommerell Diverticulum  Kommerell diverticulum may simulate left aortic arch on frontal chest radiograph  Tracheal indentation on lateral chest radiograph  Differentiation usually requires cross-sectional imaging Right Aortic Arch With Mirror-Image Branching and Aortic Diverticulum  Lack of left subclavian artery inferior tethering  Aortic diverticulum is more common in DAA with atretic left aortic arch Left Pulmonary Artery Sling  Anterior esophageal and posterior tracheal indentations  May be associated with tracheomalacia Mediastinal Mass  Mediastinal masses can cause tracheal compression PATHOLOGY General Features  Etiology o Persistence of right and left 4th aortic arches  Associated abnormalities o Typically an isolated lesion (i.e., without congenital heart disease) o Tracheobronchomalacia Gross Pathologic & Surgical Features  Tight vascular ring with tracheal and esophageal compression  Dominant right arch: ˜ 70% CLINICAL ISSUES Presentation  Most common signs/symptoms o Children  Dyspnea, often during feeding  Stridor  Apnea o Adults  May be asymptomatic  Esophageal obstruction (i.e., dysphagia) Demographics  Most common symptomatic vascular ring  Typically manifests in neonates  Affects 0.05-0.3% of general population Treatment  Surgical division of smaller or atretic aortic arch and ligamentum arteriosus SELECTED REFERENCES 1. Dillman JR et al: Common and uncommon vascular rings and slings: a multi-modality review. Pediatr Radiol. 41(11):1440-54; quiz 1489-90, 2011 2. Kellenberger CJ: Aortic arch malformations. Pediatr Radiol. 40(6):876-84, 2010 P.2:18

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(Left) Esophagram in a neonate with stridor shows right and smaller left indentations of the esophagus on the frontal view due to the DAA. There is posterior indentation in the lateral view related to the RAA. (Right) Frontal 3D reformation from chest CT in an asymptomatic patient with DAA shows higher and larger right vs. left tracheal indentations on the AP reformation. Note posterior indentation related to the right aortic arch in the lateral reformation.

(Left) Axial chest CTA in an asymptomatic adult patient with double aortic arch with areas of partially atretic left aortic arch (cephalad to caudad progression) demonstrates a right aortic arch and a left aortic arch . (Right) Axial chest CTA in the same patient shows a right aortic arch . Note the areas of stenosis along the left aortic arch. Note that the trachea has slightly decreased in diameter as it courses caudally.

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(Left) Axial chest CTA in the same patient shows that the right aortic arch and left aortic arch have joined into 1 descending thoracic aorta . The trachea remains slightly narrowed. (Right) Axial chest CTA more inferiorly shows a common left descending thoracic aorta . The trachea now resumes a normal diameter. P.2:19

(Left) Coronal MPR-rendered chest CTA in an asymptomatic adult with DAA shows a mild concentric narrowing of the mid trachea with a more prominent right paratracheal nodular opacity. (Right) Sagittal volume-rendered chest CTA (same patient) shows a mild posterior tracheal indentation , classic in DAA. This narrowing is often related to the distal portion of the right aortic arch as it courses posterior to the esophagus to join the right aortic arch.

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(Left) Axial chest CTA in the same patient shows a right aortic arch and a left aortic arch . Note that both arches are widely patent. (Right) Axial chest CTA in the same patient shows a right aortic arch and a left aortic arch . Classically, the right aortic arch appears larger in diameter as compared to the left. The trachea and esophagus are completely surrounded by the vascular ring. Occasionally, as in this case, patients may be asymptomatic.

(Left) Axial chest CTA in the same patient, more inferiorly, shows the descending aorta coursing to the left of the midline, the most common variation of DAA. (Right) Axial MIP reformation from chest CTA in the same patient better allows the comparison of diameters of the right and left aortic arches and demonstrates the complete vascular ring encasing the trachea and esophagus. P.2:20

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(Left) Sagittal reformation from chest CTA in an adult with a double aortic arch shows the distal right aortic arch causing mild posterior indentation of the trachea. Also note the ascending aorta and the proximal left aortic arch . (Right) Coronal reformation from chest CTA in the same patient shows a more cephalad larger right aortic arch and a more caudal smaller left aortic arch .

(Left) Frontal view 3D volume-rendered reformation of a CTA demonstrates the 4-artery sign with 2 ventral carotid arteries in front of 2 dorsal subclavian arteries . Note the ascending aorta and left-sided descending aorta. (Right) Superior view 3D reformation from chest CTA in the same patient shows a double aortic arch. The right aortic arch and left aortic arch form a complete vascular ring through which the trachea and the esophagus (not seen) course.

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(Left) PA chest radiograph in a patient with mild dysphagia with double aortic arch and atretic left aortic arch shows bilateral paratracheal opacities that represent the right and left aortic arches. Note mild tracheal narrowing . (Right) Lateral chest radiograph in the same patient shows mild indentation of the posterior trachea. Radiographically, this is similar to right aortic arch with aberrant left subclavian artery and Kommerell diverticulum. Cross-sectional imaging is often needed. P.2:21

(Left) Axial chest CTA in the same patient shows mild dysphagia with double aortic arch and atretic left aortic arch. Note the retroesophageal course of the right aortic arch with anterior displacement of the trachea and esophagus. The presence of a double aortic arch and the retroesophageal course often result in dysphagia and stridor. (Right) Axial chest CTA in the same patient with mild dysphagia shows the descending thoracic aorta coursing on the left.

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(Left) Sagittal chest CTA in the same patient shows the distal right aortic arch and its impression on the posterior tracheal margin . Note the esophageal narrowing with mildly dilated proximal esophagus , which causes the patient's dysphagia. (Right) Coronal minimal intensity projection from chest CTA in the same patient shows mild bilateral mid tracheal narrowing .

(Left) Posterior 3D reformation from chest CTA in the same patient shows that the right aortic arch is higher and larger than the left. Note the distal left aortic arch . (Right) Oblique 3D reformatted CTA in the same patient shows inferior tethering of the left subclavian artery , a specific finding to differentiate this variant from a right aortic arch and aberrant left subclavian artery.

Right Aortic Arch Right Aortic Arch Santiago Martínez-Jiménez, MD Key Facts Terminology  Right aortic arch (RAA) o Aortic arch located to the right of trachea  Common variations o RAA with aberrant left subclavian artery (ALSA) ± diverticulum of Kommerell (DK) o RAA with mirror-image branching Imaging  Radiography

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Right paratracheal nodular opacity and indentation of right tracheal margin on frontal chest radiograph DK: Retroesophageal opacity with indentation of posterior tracheal margin on lateral chest radiograph

CT

o RAA with ALSA with retroesophageal course ± DK o RAA with mirror-image branching o RAA with left descending aorta with retroesophageal aortic segment Top Differential Diagnoses  Double aortic arch  Mediastinal mass Clinical Issues  RAA with ALSA o Most patients are asymptomatic o Some patients with DK may have dysphagia or stridor  RAA with mirror-image branching o Cyanotic congenital heart disease  RAA with left descending aorta (circumflex aorta) o Ductus ligament between pulmonary artery and ALSA constitutes vascular ring, often loose, that may be symptomatic (i.e., dysphagia, stridor).  Treatment o Symptomatic RAA with ALSA/DK may require division of ligamentum via left thoracotomy

(Left) PA chest radiograph in a patient with RAA and ALSA without DK shows RAA that appears as a right paratracheal nodular opacity with right tracheal indentation. (Right) Lateral chest radiograph in the same patient shows normal configuration of the trachea . ALSA with DK can be differentiated from ALSA without DK based on the presence of indentation of the posterior margin of the trachea in the former, however differentiation this is not always possible.

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(Left) Axial chest CTA in an asymptomatic patient with RAA , ALSA , and descending thoracic aorta on the right reveals an incidentally noted persistent left superior vena cava draining into the coronary sinus. (Right) Coronal reformation CTA in the same patient shows ALSA arising as the last aortic branch. There is no DK. The lack of DK usually indicates absence of a ductus ligament; therefore, this does not constitutes a vascular ring. P.2:23

TERMINOLOGY Abbreviations  Right aortic arch (RAA) Definitions  Aortic arch located to the right of trachea  Common variations o RAA with aberrant left subclavian artery (ALSA) ± diverticulum of Kommerell (DK)  Diverticulum of Kommerell  Saccular dilatation at level of ALSA  Implies ligamentum arteriosum and vascular ring o RAA with mirror-image branching  Uncommon variations o RAA with left descending aorta (circumflex aorta) o RAA with isolation of left subclavian artery o RAA with aberrant brachiocephalic artery IMAGING General Features  Best diagnostic clue o Indentation of right tracheal margin due to paratracheal mass Radiographic Findings  Radiography o General features for different variations  Right paratracheal nodular opacity  Indentation of right tracheal margin o RAA with ALSA  ± diverticulum of Kommerell  If with diverticulum of Kommerell  Retroesophageal nodular opacity  Indentation of posterior tracheal margin  Can simulate left aortic arch (LAA) on frontal projection o RAA with mirror image branching  ± dextrocardia  Cardiomegaly associated with congenital heart disease o RAA with unilateral absence of pulmonary artery 104

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Hypoplastic ipsilateral hemithorax with contralateral hyperinflation Absent or grossly ↓ pulmonary vascular markings

CT Findings  RAA with ALSA o 4 great vessels in the following order: Left carotid, right carotid, right subclavian, ALSA o ALSA with retroesophageal course o ± DK (bulbous dilatation at origin of ALSA)  RAA with mirror-image branching o 3 great vessels in the following order: Left brachiocephalic, right carotid, right subclavian o Rarely blind aortic diverticulum (similar to DK)  RAA with left descending aorta (circumflex aorta) o Retroesophageal aortic segment  RAA with isolation of left subclavian artery o 3 great vessels in the following order: Left carotid, right carotid, right subclavian o Left subclavian artery connected to aortic arch by ductus ligament MR Findings  MR imaging is similarly accurate compared to CT to assess for variations of vascular anatomy DIFFERENTIAL DIAGNOSIS Double Aortic Arch  Differentiation on radiography may be impossible as DK can simulate LAA  CT and MR are diagnostic o Patent RAA and LAA with larger RAA and smaller LAA o Double aortic arch with atretic LAA  Inferior tethering of left subclavian artery  Blind aortic diverticulum is more common in double aortic arch Mediastinal Mass  Right paratracheal lymphadenopathy and esophageal neoplasm can simulate RAA on chest radiography PATHOLOGY General Features  Etiology o Embryologic considerations  RAA with ALSA develops from interruption between left common carotid and left subclavian arteries  RAA with mirror-image branching develops from interruption distal to left subclavian artery  Associated abnormalities o RAA with ALSA ± DK: Low incidence of congenital heart disease o RAA with mirror-image branching: High incidence of congenital heart disease (˜ 98%)  RAA is present in 25% of patients with tetralogy of Fallot  RAA is present in 25-50% of patients with truncus arteriosus CLINICAL ISSUES Presentation  Most common signs/symptoms o RAA with ALSA  Patients with DK may have dysphagia or stridor Natural History & Prognosis  Determined mostly by coexisting congenital heart disease Treatment  Symptomatic RAA with ALSA/DK o Requires division of ligamentum via left thoracotomy  RAA with mirror-image branching o Treatment of associated congenital heart disease SELECTED REFERENCES 1. Kanne JP et al: Right aortic arch and its variants. J Cardiovasc Comput Tomogr. 4(5):293-300, 2010 2. Türkvatan A et al: Congenital anomalies of the aortic arch: evaluation with the use of multidetector computed tomography. Korean J Radiol. 10(2):176-84, 2009 3. Weinberg PM: Aortic arch anomalies. J Cardiovasc Magn Reson. 8(4):633-43, 2006 P.2:24

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(Left) PA chest radiograph in an asymptomatic patient with RAA, ALSA, and DK shows RAA as a right paratracheal nodular opacity with an indentation of the right tracheal margin. (Right) Lateral chest radiograph in the same patient shows an indentation of the posterior tracheal margin , which relates to the presence of a DK. This suggests that mirror-image branching is not present. Note that DK implies the presence of a vascular ring, which may or may not be symptomatic.

(Left) Composite axial chest CTA image in a patient with RAA, ALSA, and DK demonstrates RAA and ALSA/DK shows mild dilatation of the esophagus proximal to the DK. (Right) Sagittal reformation from chest CTA in the same patient shows posterior tracheal indentation by the DK . DK implies the presence of a ductus ligament and constitutes a vascular ring. While the majority of patients are asymptomatic, DK is an etiology of dysphagia whenever present.

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(Left) Oblique coronal reformation from chest CTA in the same patient shows bulbous configuration of the origin of the ALSA, a classic feature of DK. DK is a consequence of the presence of a ligamentum arteriosum. Pathophysiologically, patients with DK may have symptoms (e.g. dysphagia) related to a vascular ring completed by the ligamentum arteriosum. (Right) Anterior and posterior CTA 3D reformations in the same patient with RAA, ALSA , and DK shows bulbous appearance of the DK. P.2:25

(Left) Coronal reformation from chest CTA in a patient with RAA, ALSA, and DK shows mild normal indentation of the right tracheal margin from the right aortic arch. In this case, there is no significant stenosis of the trachea. (Right) Frontal projection esophagram in a pediatric patient with RAA and ALSA shows an oblique indentation on the esophageal lumen, which is caused by the ALSA. Note that esophagrams are often useful when assessing vascular rings in symptomatic patients.

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(Left) PA chest radiograph in a patient with RAA , ALSA, & DK is shown. Frequently, when a RAA is associated with a DK, the latter can sometimes simulate the presence of a normal LAA thus appearing as a DAA on the frontal chest radiograph. An important clue for differentiation is that the DK does not exert an indentation on the left lateral margin of the trachea as would be expected with a coexistent LAA. (Right) Frontal DSA aortogram in a patient with RAA shows also ALSA and DK .

(Left) Axial chest CTA in a patient with RAA with mirror-image branching and aortic diverticulum with stridor shows a right-sided descending thoracic aorta . (Right) Posterior 3D view from CTA in the same patient is shown. Despite the presence of a blind aortic diverticulum , this case represents a RAA, not double aortic arch with atretic LAA, given the lack of inferior tethering of the left subclavian artery. (Courtesy R. Reina, MD.) P.2:26

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(Left) Axial SSFP MR images of the chest in a patient with RAA with mirror-image branching and tetralogy of Fallot demonstrate the right descending thoracic aorta and the left brachiocephalic artery , arising as the 1st branch of the aortic arch. (Right) Coronal 3D view from thoracic MRA in the same patient shows the RAA . 3D reformation provides an anatomic overview that may aid in communicating findings to surgeons and other clinicians.

(Left) Lateral scout view in a patient with RAA with left descending aorta (a.k.a. circumflex aorta) shows marked indentation of the posterior margin of the trachea due to a large mediastinal mass effect. (Right) AP chest CTA in the same patient shows RAA and left descending thoracic aorta with a retroesophageal aortic arch that displaces the trachea anteriorly. A circumflex aorta implies a vascular ring and can be symptomatic.

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(Left) PA radiograph in a patient with RAA (mirror-image branching type) and unilateral absence of the pulmonary artery (UAPA) presenting with recurrent infection shows RAA with indentation of the right tracheal margin and hypoplastic left hemithorax. (Right) Lateral chest radiograph in the same patient shows a normal right pulmonary artery anterior to the left upper lobe bronchus and absent left pulmonary artery. P.2:27

(Left) Axial chest CTA images in a patient with RAA (mirror-image branching type) and UAPA presenting with recurrent infections reveal only a right pulmonary artery . (Right) Axial SSFP chest MR images in a patient with RAA (with ALSA and DK) and left UAPA show the presence of a right pulmonary artery with an absence of a left pulmonary artery at the level of the pulmonary trunk. DK and ALSA constitute an asymptomatic vascular ring.

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(Left) Axial chest CTA images in a patient with RAA with isolation of the left subclavian artery show a relatively normal in diameter left subclavian artery that more caudally appears punctate . (Right) Coronal MIP reformation from chest CTA in the same patient shows a right aortic arch and an obliterated proximal subclavian artery with distal reconstitution via retrograde flow from the ipsilateral vertebral artery.

(Left) PA chest radiograph in a patient with RAA with mirror-image branching and esophageal cancer shows RAA and left paratracheal mass . On radiographs, this presentation may mimic a DK or double aortic arch. (Right) Axial chest NECT in the same patient shows RAA , proximal esophageal dilatation , and esophageal circumferential mass . Some cases with atypical features on chest radiography may require cross-sectional imaging.

Persistent Fifth Arch Persistent Fifth Arch Suhny Abbara, MD, FSCCT Key Facts Terminology  Rare congenital vascular anomaly  May be isolated or associated with other abnormalities o Complex congenital cardiac heart disease o Vascular anomalies such as coarctation of aorta o Skeletal anomalies  2 distinct forms

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Systemic-to-systemic connection: 5th arch arises at brachiocephalic trunk and reconnects at descending aorta Systemic-to-pulmonary connection: 5th arch connects with embryologic remnant of 6th aortic arch, which is usually left pulmonary artery

Imaging  Contrast-enhanced MRA most appropriate in children with suspected persistent 5th arch  Short segment of “duplication” the aortic arch with 2 parallel distinct lumen in systemic-to-systemic connection  Abnormal vessel connecting aorta with isolated pulmonary artery in systemic-to-pulmonary connection Clinical Issues  Often presents soon after birth due to associated cardiac or vascular defects o Ventricular septal defect o Pulmonic valve stenosis or atresia o Complex congenital heart disease  In case of coarctation/obstruction, surgical patching or conduit interposition may be indicated

(Left) Aortic arch “candy cane” view of CTA shows separation of the aortic arch into 2 distinct vessels (*). The superior is the normal 4th aortic arch giving rise to the arch vessels. The inferior is the persistent 5th aortic arch. (Right) Coronal CTA in the same patient shows the short axis of aortic arches with a double barrel appearance (*). The 4th and persistent 5th arch have a “figure of 8” configuration in short axis, which allows differentiation from dissection.

(Left) Oblique 3D volume-rendered reconstruction shows the relationship of the 4th arch with the arch vessels. Note the abnormal persistent 5th arch arising from aorta at level of brachiocephalic trunk and reentering into descending thoracic aorta at its isthmus. (Right) Oblique 3D reconstruction of skull in the same patient shows cleft palate . Other skeletal anomalies in this patient include fused ribs and hemi vertebra (not shown). 112

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TERMINOLOGY Synonyms  Ipsilateral double aortic arch  Double lumen aortic arch Definitions  Rare congenital vascular anomaly of aortic arch o May be isolated o Often associated with other congenital cardiac, vascular, or skeletal anomalies  2 distinct forms o Systemic-to-systemic connection  5th arch arises at brachiocephalic trunk and reconnects at descending aorta o Systemic-to-pulmonary connection  5th arch connects with embryologic remnant of 6th aortic arch, which is usually left pulmonary artery IMAGING General Features  Best diagnostic clue o Short segment of “duplication” of aortic arch with 2 parallel distinct lumens  May have interrupted arch o Abnormal vessel connecting aorta with pulmonary artery  Location o Aortic arch  Cephalad of arches is 4th arch, which gives rise to arch vessels  Lower arch is persistent 5th arch Radiographic Findings  Radiography o May demonstrate associated findings such as vertebral anomalies CT Findings  CTA o 2 distinct left aortic arches with what may appear as septation separating them o Double barrel appearance on coronal oblique short axis views o May have interrupted arch o May show anomalous connection between aorta and isolated left pulmonary artery o May demonstrate associated cardiovascular and skeletal abnormalities MR Findings  Same as CTA findings  Superior to echocardiography due to acoustic window restrictions near aortic arch Imaging Recommendations  Best imaging tool o CTA or MRA  Protocol advice o Contrast-enhanced MRA most appropriate in children with suspected persistent 5th arch DIFFERENTIAL DIAGNOSIS Aortic Dissection  Easily differentiated by double barrel appearance of persistent 5th arch: 2 round lumens form “figure of 8” on arch short axis views Patent Ductus Arteriosus  Systemic-to-pulmonary connection may mimic large patent ductus arteriosus CLINICAL ISSUES Presentation  Most common signs/symptoms o Often presents soon after birth due to associated cardiac or vascular defects  Ventricular septal defect  Pulmonic valve or artery stenosis/atresia  Interruption of aortic arch 113

Diagnostic Imaging Cardiovascular  Complex congenital heart disease Clinical profile o Association with intrauterine thalidomide exposure and chromosomal disorders o Associated cardiovascular anomalies include  Coarctation  Pulmonary atresia or stenosis  Transposition of great arteries  Truncus arteriosus  Pentalogy of Fallot  Patent ductus arteriosus, ventricular septal defect  Tricuspid atresia Demographics  Epidemiology o Extremely rare congenital malformation Treatment  In case of coarctation/obstruction, surgical patching or conduit interposition may be indicated DIAGNOSTIC CHECKLIST Consider  May have obstruction due to associated coarctation o Check blood pressure (BP) difference between upper and lower extremities (BP in both arms) SELECTED REFERENCES 1. Kligerman S et al: Persistent fifth aortic arch in a patient with a history of intrauterine thalidomide exposure. J Cardiovasc Comput Tomogr. 3(6):412-4, 2009 2. Kirsch J et al: Magnetic resonance angiography of an ipsilateral double aortic arch due to persistent left fourth and fifth aortic arches. Pediatr Radiol. 37(5):501-2, 2007 3. Zhao YH et al: Surgical treatment of persistent fifth aortic arch associated with interrupted aortic arch. Ann Thorac Surg. 84(3):1016-9, 2007 4. Zhong Y et al: Contrast-enhanced magnetic resonance angiography of persistent fifth aortic arch in children. Pediatr Radiol. 37(3):256-63, 2007 5. Hwang MS et al: Isolated persistent fifth aortic arch with systemic-to-pulmonary arterial connection. J Thorac Cardiovasc Surg. 126(5):1643-4, 2003 

Pulmonary Sling Pulmonary Sling Santiago Martínez-Jiménez, MD Key Facts Terminology  Left pulmonary artery sling (LPAS)  Left PA arising from posterior aspect of right PA, forming a “sling” around distal trachea as it courses leftward between trachea and esophagus Imaging  Radiography o Right-sided hyperinflation: LPAS type I o Bilateral hyperinflation: LPAS type II o Long-segment tracheal stenosis: LPAS type II o Leftward, low pseudocarina: LPAS type II  CTA o LPAS arising from proximal right PA o LPAS passes between esophagus and trachea  Low inverted T pseudocarina to the left of midline  Complete tracheal rings: Stenosis with round (rather than oval) appearance Top Differential Diagnoses  Double aortic arch and right aortic arch with aortic diverticulum  Middle mediastinal mass Clinical Issues  Infants: Stridor, recurrent pneumonia  Adults: Often incidental finding  LPAS type II: ↑ morbidity and mortality due to associated anomalies 114

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Treatment o Asymptomatic LPAS type I: No treatment required o LPAS type I with respiratory symptoms: Left PA reimplantation, patent ductus arteriosus, or ductus ligament ligation o LPAS type II: Left PA reimplantation and sliding tracheoplasty

(Left) Graphic depicts left pulmonary artery sling (LPAS) type I (IA = normal tracheal branching; IB = tracheal bronchus) and type II, which has a low-level inverted T-shaped carina (IIA = tracheal bronchus at usual carinal level; IIB = low pseudocarina). (Right) AP chest radiograph in a patient with LPAS type II shows asymmetric lung volumes (left > right) with rightward cardiomediastinal shift. In LPAS type I, right-sided hyperinflation is more common due to bronchial compression or bronchomalacia.

(Left) Axial chest CTA in a pediatric patient with LPAS type I shows the classic distribution of the LPAS, arising from the right PA around the distal trachea and morphologically resembling a sling. (Right) Frontal projection from bronchography in a pediatric patient with LPAS type IIA shows an anomalous tracheobronchial pattern. Note a tracheal bronchus with low, leftward-deviated pseudocarina and right bridging bronchus with lack of filling in left main bronchus. P.2:31

TERMINOLOGY Abbreviations  Left pulmonary artery sling (LPAS) Definitions

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Left pulmonary artery (PA) originates from posterior aspect of right PA, forming a “sling” around distal trachea as it courses toward the left, between trachea and esophagus IMAGING Radiographic Findings  Radiography o LPAS type I  Right-sided hyperinflation (due to bronchomalacia)  Occasional left-sided hyperinflation  Occasional tracheal stenosis  Newborn period  Prolonged opacification of right lung due to retained fluid on frontal radiograph  Type IA: Normal tracheobronchial branching on frontal radiograph  Type IB: Tracheal bronchus may be seen on frontal radiograph  Right-sided indentation of carina and right main stem bronchus on frontal radiograph o LPAS type II  Bilateral hyperinflation  Right-sided volume loss  Long-segment tracheal stenosis  Poorly defined trachea with leftward shifted pseudocarina and horizontal main bronchi o LPAS types I and II: Soft tissue mass between mid trachea and esophagus on lateral radiograph Fluoroscopic Findings  Esophagram o Variable positivity and specificity o Unnecessary if clinical suspicion of LPAS o Anterior and posterior esophageal indentation on lateral projection CT Findings  CTA o LPAS arising from proximal right PA o LPAS passes between esophagus and trachea o Assess arterial diameter and stenosis o Excellent depiction of tracheal anatomy and variations (better on coronal reformations) o LPAS type I  LPAS abutting distal trachea and right main bronchus at T4-T5 level  Airway branching pattern differentiates types IA and IB  LPAS type IA: Normal branching  LPAS type IB: Tracheal bronchus  Tracheal bronchus  Tracheobronchomalacia  Unilateral pulmonary hyperinflation o LPAS type II  LPAS abutting distal trachea at level T5-T6  Long-segment tracheobronchial stenosis  Typically from tracheal bronchus to abnormally low pseudocarina  Segment often referred to as left intermediate left bronchus  Other tracheobronchial branching abnormalities  Right bridging bronchi (i.e., crossing midline from origin in medial left main bronchus)  Low inverted T pseudocarina to the left of midline with bridging and left main bronchi  Complete tracheal rings: Stenosis with round (rather than oval) appearance  Tracheobronchomalacia  Pulmonary abnormalities  Right pulmonary hypoplasia and agenesis with small or absent right PA  Occasional left lung hypoplasia MR Findings  Equally accurate to assess anatomic abnormalities  Main advantage: Lack of ionizing radiation  Disadvantages: Lungs and airways are suboptimally assessed 116

Diagnostic Imaging Cardiovascular o Less readily available o Longer scan times often requiring anesthesia and sedation o Suboptimal assessment of lungs and airways due to intrinsic low signal  Cardiac-gated and respiratory-gated techniques are recommended  Consider multiplanar black blood (e.g., HASTE) and white blood (e.g., SSFP) sequences Echocardiographic Findings  Echocardiogram o Distorted anatomy can make evaluation very limited o Absence of normal PA bifurcation o Anomalous origin of left PA from proximal right PA o Useful in associated congenital heart disease Imaging Recommendations  Best imaging tool o CTA faster and more available, especially in critically ill patients  Protocol advice o Axial and multiplanar reformations better display sling anatomy o Coronal reformations better display tracheobronchial stenosis DIFFERENTIAL DIAGNOSIS Double Aortic Arch and Right Aortic Arch With Aortic Diverticulum  Both can cause obstructive symptoms (e.g., stridor, dyspnea, apnea, recurrent pneumonia)  Paratracheal opacities not typically seen in LPAS on radiography  Cross-sectional imaging demonstrates vascular rings related to aortic arch &/or aortic diverticulum Middle Mediastinal Mass  e.g., lymphadenopathy bronchogenic cyst, esophageal duplication cyst  Cross-sectional imaging exhibits vascular nature of LPAS P.2:32

Congenital Lobar Emphysema (or Hyperinflation)  Hyperlucent (hyperinflated) lung similar to hyperinflation from LPAS on radiography  Cross-sectional imaging exhibits vascular nature of LPAS PATHOLOGY General Features  Etiology o Embryology  Abnormal obliteration or failure of development of left 6th aortic arch  Left postbranchial PA vessels cannot connect with left 6th branchial arch  Secondary connection is acquired to right 6th branchial arch through embryonic peritracheal primitive mesenchymal vessels o Severe stridor  May be associated with tracheobronchomalacia (often LPAS type I)  May be associated with intrinsic airway narrowing (often LPAS type II)  Compression of distal trachea and main stem bronchi may lead to hyperinflation and atelectasis  Genetics o Occasional descriptions in twins raise concern of some genetic influence  Associated abnormalities o Congenital heart disease and vascular  Atrial septal defect (ASD)  Ventricular septal defect  Patent ductus arteriosus (PDA)  Tetralogy of Fallot  Aortic coarctation  Persistent superior vena cava ± coronary sinus ASD  Interrupted aortic arch  Double aortic arch  Scimitar syndrome  Partial anomalous venous return 117

Diagnostic Imaging Cardiovascular  Pulmonary hypertension from severe hypoxia Tracheal  Tracheal stenosis  Right tracheal bronchus  Right bridging bronchus o Lung  Pulmonary sequestration  Horseshoe lung o Gastrointestinal  Imperforate anus  Biliary atresia  Absent gallbladder  Meckel diverticulum  Hirschsprung disease o VACTERL (vertebral anomalies, anal atresia or imperforate anus, cardiac anomalies, tracheoesophageal fistula, renal and limb defect)) Staging, Grading, & Classification  LPAS type I: Sling at T4-T5 (just above usual carina level); occasional tracheal stenosis o LPAS type IA: Without tracheal bronchus o LPAS type IB: With tracheal bronchus  LPAS type II: Sling at T5-T6 (lower than usual carina level) and low T-shaped carina; long segment tracheal stenosis with complete cartilaginous rings o Type IIA: Right tracheal bronchus (at usual carina level) o Type IIB: Low pseudocarina with right bridging bronchus Gross Pathologic & Surgical Features  Left PA forms a “sling” around trachea as it passes leftward between trachea and esophagus  LPAS hilum of left lung posteriorly to left main stem bronchus  Right lung hypoplasia and agenesis  Persistent superior vena cava  Severe compression of distal trachea and right main stem bronchus  Main stem bronchi have abnormal horizontal course (inverted T) with abnormal branching patterns to upper and lower lobes (types IIA and IIB)  Often associated with complete tracheal cartilaginous rings (50%) CLINICAL ISSUES Presentation  Most common signs/symptoms o Infants: Stridor, wheezing, recurrent pneumonia o Adults: Often incidental finding  Other signs/symptoms o Noisy breathing, “seal bark” cough, apnea, recurrent pulmonary infections Demographics  Age o Typically presents clinically in neonatal period  Epidemiology o LPAS type II (especially IIB) more common overall o LPAS type I more common in adults (very rare) Natural History & Prognosis  LPAS type I: ↓ morbidity and mortality  LPAS type II: ↑ morbidity and mortality due to associated anomalies o Intrinsic tracheobronchial anomalies o Congenital heart disease o Pulmonary and systemic anomalies Treatment  Asymptomatic LPAS type I: No treatment required  LPAS type I with respiratory symptoms: Left PA reimplantation, PDA, or ductus ligament ligation  LPAS type II: Left PA reimplantation and sliding tracheoplasty SELECTED REFERENCES o

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Image Gallery

(Left) Posteroanterior chest radiograph from an asymptomatic adult with LPAS type IA is shown. Patient had prior median sternotomy and CABG, but there are no other radiographic clues to suggest LPAS. (Right) Lateral chest radiograph from the same patient also lacks sensitivity to assess the vascular abnormality ( = anomalous left PA posterior to trachea). These radiographs are provided to emphasize the difficulty of establishing this abnormality in asymptomatic patients on chest radiography.

(Left) Axial CTA of the chest in the same patient shows the classic sling around the distal trachea. There is minimal tracheal stenosis that correlates with lack of symptoms. (Right) Sagittal reformation from CTA of the chest in the same asymptomatic adult with LPAS type IA shows that the anomalous left PA coursing between the trachea and the esophagus creates a mild indentation along the posterior tracheal margin without significant tracheal stenosis.

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(Left) Coronal minimum intensity projection reformation from CTA of the chest in the same patient shows unremarkable tracheal branching pattern without evidence of tracheal bronchus, consistent with LPAS type IA. (Right) Posterior 3D reformation from CTA of the chest in the same patient shows the left pulmonary artery arising from the right pulmonary artery. LPAS type IA is the most common variant seen in previously undiagnosed asymptomatic adults. P.2:34

(Left) Axial CECT of the chest in a pediatric patient with LPAS type IIB with symptomatic airway obstruction shows LPAS and hypoplastic (small) right lung with rightward displacement of the heart/mediastinum. (Right) Axial CECT of the chest in the same patient shows low inverted T pseudocarina with horizontalization of the main bronchi (mostly seen on 1 image) and LPAS coursing posterior to the right main stem bronchus.

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(Left) Axial CECT of the chest in the same patient shows normal aspect of the trachea proximal to the vascular abnormality with a somewhat dilated esophagus . (Right) Axial CECT of the chest shows tracheal narrowing above the area of left pulmonary artery sling in the same patient, who has long-segment tracheal stenosis as well as patulous esophagus .

(Left) Axial T1WI MR in a pediatric patient with LPAS type II, symptomatic airway obstruction, and horseshoe lung in the retrocardiac area shows the left pulmonary artery coursing posterior to the pseudocarina. (Right) Axial MR in the same patient with symptomatic airway obstruction and horseshoe lung in the retrocardiac area shows the left pulmonary artery coursing around distal trachea . MR is as accurate as CT to depict vascular and airway anatomy. P.2:35

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(Left) Axial chest CTA in a patient with LPAS type IIB and right aortic arch with mirror-image branching with aortic diverticulum with stridor shows descending thoracic aorta , blind aortic diverticulum , and dilated esophagus . (Courtesy R. Reina, MD.) (Right) Axial chest CTA in the same patient shows LPAS and tracheal stenosis with round configuration from complete tracheal rings. (Courtesy R. Reina, MD.)

(Left) Axial chest CTA in the same patient shows low pseudocarina and bronchial horizontalization . (Courtesy R. Reina, MD.) (Right) Axial MIP reformation from chest CTA in the same patient shows right aortic arch with mirrorimage branching and blind aortic diverticulum . (Courtesy R. Reina, MD.)

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(Left) Posterosuperior 3D reformation from chest CTA in the same patient shows the pulmonary artery sling . (Courtesy R. Reina, MD.) (Right) Posterior 3D reformation from chest CTA in the same patient shows aortic diverticulum ending blindly. LPAS and aortic diverticulum can cause airway obstruction. (Courtesy R. Reina, MD.)

D-Transposition of Great Arteries D-Transposition of Great Arteries Brett W. Carter, MD Key Facts Terminology  Atrioventricular concordance and ventriculoarterial discordance o Aorta arises from right ventricle; pulmonary artery arises from left ventricle  Category: Cyanotic, cardiomegaly, increased pulmonary vascularity Imaging  Chest radiography: May be normal in neonates o “Egg on a string” appearance of heart o Narrow superior mediastinum  CTA and MR o Direct visualization of abnormal anatomy o Identification of postoperative complications  Echocardiogram: Optimal for preoperative diagnosis Top Differential Diagnoses  L-transposition  Hypoplastic left heart syndrome  Total anomalous pulmonary venous return  Truncus arteriosus Pathology  Associated with abnormalities of heart, coronary arteries, and pulmonary arteries Clinical Issues  Symptoms: Peripheral cyanosis; tachypnea, weakness, and fatigue; failure to thrive  Treatment o Prostaglandin E1 keeps ductus arteriosus open o Balloon atrial septostomy (Rashkind) o Surgical (early): Arterial switch with transposition of coronary arteries (Jatene) o Surgical (late): Rerouting of venous flow in atria with pericardial baffle (Mustard) or reorientation of atrial septum (Senning)

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(Left) Graphic shows the atrioventricular concordance and ventriculoarterial discordance of D-transposition. The aorta is anterior and connected via the infundibulum to the right ventricle. The pulmonary trunk is posterior and directly connected to the left ventricle. (Right) Anteroposterior chest radiograph demonstrates the “egg on a string” appearance of the cardiomediastinal silhouette in D-transposition. The superior mediastinum is narrow , and the heart is globular in shape.

(Left) Sagittal MRA demonstrates the anteriorly located aorta and the posteriorly located pulmonary trunk . (Right) Axial CECT following an arterial switch procedure demonstrates that the pulmonary trunk is positioned anterior to the ascending thoracic aorta . Arterial switch procedures, such as the Jatene procedure, are typically performed early in life, before the left ventricle adjusts to the lower pressure of the pulmonary circulation and becomes unable to sustain systemic pressures. P.2:37

TERMINOLOGY Abbreviations  Dextro transposition of great arteries (D-TGA)  D = dextro = right Definitions  Atrioventricular concordance and ventriculoarterial discordance o Aorta arises from right ventricle (RV); pulmonary trunk arises from left ventricle (LV)  Anatomic arrangement represented by the designation “S, D, D” (Van Praagh segmental approach) o S: Visceroatrial situs solitus  Right atrium to the right of left atrium 124

Diagnostic Imaging Cardiovascular  Inferior vena cava to the right of aorta  Liver on the right  Spleen on the left o D: D-loop  Morphologic RV on the right  Morphologic LV on the left o D: D-malposition of aortic valve relative to pulmonary valve  Aortic valve located to the right of and anterior to pulmonic valve  Great vessels parallel instead of crossing  Category: Cyanotic, cardiomegaly, increased pulmonary vascularity  Hemodynamics o RV → systemic circulation: Pressure overload o LV → pulmonary circulation: Volume overload o Incompatible with life without flow admixture  Patent ductus arteriosus (PDA)  Patent foramen ovale (PFO)  Ventricular septal defect (VSD) IMAGING General Features  Best diagnostic clue o Aorta and pulmonary trunk lie parallel o Aortic valve located to the right of and anterior to pulmonic valve Radiographic Findings  Radiography o Chest radiographs may be normal in neonates o “Egg on a string” appearance of heart  Cardiomegaly  Narrow pedicle due to orientation of transposed great arteries o Narrow superior mediastinum with radiographic absence of thymus CT Findings  CTA o Direct visualization of abnormal anatomy  Atrioventricular concordance and ventriculoarterial discordance o Postoperative  Anteriorly positioned pulmonary trunk and posteriorly positioned aorta in same sagittal plane  Traction on both branch pulmonary arteries (PAs) may lead to stenosis  Ascending aorta may compress anterior trachea or left main bronchus o Preferred modality after placement of metallic stents for branch PA stenosis  Cardiac gated CTA o Evaluates ventricular function  Best performed at 80 kVp and low MA setting to minimize radiation dose o Defines coronary anatomy and course MR Findings  T1WI o Cardiac-gated axial images for segmental cardiac analysis  Atrioventricular concordance and ventriculoarterial discordance  Associated cardiac and extracardiac abnormalities  Postoperative assessment of PA stenosis  T1WI C+ o May be used to detect ischemia complicating coronary transposition  Late gadolinium enhancement  MRA o Postoperative  Detect PA stenosis o MR coronary angiography with navigator-echo respiratory gating  Evaluate patency of transposed coronary arteries o Velocity-encoded phase-contrast MRA with flow-velocity measurements  Allows calculation of gradients across stenoses (PAs and baffles) 125

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SSFP cine o Evaluate cardiac function  RV dysfunction may be seen following switch procedures  Calculate ventricular volume o Postoperative  Baffle obstruction after Mustard/Senning procedure Echocardiographic Findings  Echocardiogram o Optimal for preoperative diagnosis and assessment  Identification of atria, ventricles, great arteries, and their connections  Identification of PFO, VSD, and PDA o Proximal coronary artery anatomy Angiographic Findings  Conventional o Cardiac catheterization for Rashkind procedure (balloon atrial septostomy) Imaging Recommendations  Echocardiography allows for complete preoperative diagnosis in majority of cases  CT or MR for postoperative complications of PAs and baffles DIFFERENTIAL DIAGNOSIS L-Transposition  Atrioventricular and ventriculoarterial discordance  Category: Dependent on associated anomalies o LV outflow tract (subpulmonic) obstruction: Cyanotic P.2:38

o VSD: Acyanotic Hypoplastic Left Heart Syndrome  Hypoplasia/atresia of ascending aorta, aortic valve, LV, and mitral valve  Most severe congenital heart lesion; presents in neonatal period with congestive heart failure, cardiogenic shock, and cyanosis  Category: Cyanotic, cardiomegaly, increased pulmonary vascularity  Best diagnostic clue: Hypoplasia of ascending aorta and LV Total Anomalous Pulmonary Venous Return  Abnormal connection of pulmonary veins to right atrium, coronary sinus, and systemic veins (or their tributaries) resulting in left-to-right shunt  Type 1: “Snowman” heart appearance on plain film  Type 2: Indistinguishable from atrial septal defect on plain film  Types 1, 2: Initially asymptomatic, followed by congestive heart failure  Type 3: Small heart, pulmonary edema o Severe cyanosis at birth Truncus Arteriosus  Common arterial vessel giving rise to aorta, pulmonary trunk, and coronaries  Cyanosis, cardiomegaly, increased pulmonary vascularity  Cardiac anomaly most commonly associated with right aortic arch PATHOLOGY General Features  Etiology o Embryology  Faulty separation of aorta and PA from primitive bulbus cordis (conotruncus) o Associated with maternal diabetes  Associated abnormalities o Abnormalities of heart and aorta  VSD present at birth in 50% of cases  Right ventricular hypoplasia  Overriding atrioventricular valves  Aortic coarctation  Interrupted aortic arch 126

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Abnormalities of coronary arteries  Left circumflex originates from right coronary artery  Single coronary ostium o Abnormalities of pulmonary arteries  Pulmonary atresia  Pulmonary stenosis o Isolated abnormality: 90% of cases Staging, Grading, & Classification  Simple o No additional cardiac abnormalities  Complex o Presence of additional cardiac abnormalities Gross Pathologic & Surgical Features  Infundibulum of RV connected to aortic valve, anterior and slightly to the right of midline (D-loop)  LV connected without infundibulum to pulmonary valve, posterior and slightly to the left of aortic valve CLINICAL ISSUES Presentation  Most common signs/symptoms o Peripheral cyanosis  Other signs/symptoms o Tachypnea, weakness, and fatigue o Failure to thrive o Syncope and clubbing may develop if left untreated Demographics  Gender o M>F  Epidemiology o Incidence: 315 in 1,000,000 live births o 5% of congenital heart diseases o 2nd most common cyanotic congenital cardiac disorder diagnosed in 1st year of life Natural History & Prognosis  Early death without communicating shunt  Large VSD: Congestive heart failure in neonatal period  Patients with large VSD and subpulmonic stenosis: Mild symptoms, may survive without treatment  Long-term prognosis determined by potential coronary abnormalities  Transposition with early arterial switch: Good prognosis Treatment  Prostaglandin E1 keeps ductus arteriosus open  Balloon atrial septostomy (Rashkind)  Surgical (early): Arterial switch with transposition of coronary arteries (Jatene) o Complications: Branch PA stenosis, PA hypertension  Surgical (late): Rerouting of venous flow in atria with pericardial baffle (Mustard) or reorientation of atrial septum (Senning) o Complications: RV failure, atrial thrombosis, arrhythmias o Late arterial switch not possible due to low-pressure LV (supplying pulmonary circulation) not being able to sustain systemic pressures SELECTED REFERENCES 1. Frank L et al: Cardiovascular MR imaging of conotruncal anomalies. Radiographics. 30(4):1069-94, 2010 2. Lapierre C et al: Segmental approach to imaging of congenital heart disease. Radiographics. 30(2):397-411, 2010 3. Ferguson EC et al: Classic imaging signs of congenital cardiovascular abnormalities. Radiographics. 27(5):1323-34, 2007 4. Laffon E et al: Quantitative MRI comparison of pulmonary hemodynamics in mustard/senning-repaired patients suffering from transposition of the great arteries and healthy volunteers at rest. Eur Radiol. 16(7):1442-8, 2006 5. Mohrs OK et al: Time-resolved contrast-enhanced MR angiography of the thorax in adults with congenital heart disease. AJR Am J Roentgenol. 187(4):1107-14, 2006 6. Warnes CA: Transposition of the great arteries. Circulation. 114(24):2699-709, 2006 P.2:39

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Image Gallery

(Left) PA chest radiograph demonstrates a narrowing of the superior mediastinum in a patient with Dtransposition. (Right) Three-chamber view from a cardiac-gated CTA shows the atrioventricular concordance and ventriculoarterial discordance characteristic of D-transposition. The morphologic right atrium connects to the morphologic right ventricle , but the aorta arises from the right ventricular outflow tract.

(Left) Coronal balanced SSFP image of a patient following atrial switch procedure shows baffling of the superior vena cava and inferior vena cava to the left atrium/ventricle. The atrial switch, or Senning, procedure may be performed when patients are not candidates for the arterial switch procedure. (Right) Axial reformatted CTA image of a different patient demonstrates pulmonary venous baffling to the right atrium/ventricle following atrial switch procedure.

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(Left) Anteroposterior chest radiograph of a patient with D-transposition treated with arterial switch procedure demonstrates marked enlargement of the pulmonary arteries , consistent with pulmonary arterial hypertension. (Right) Axial T2WI MR of the same patient shows enlargement of the pulmonary trunk and left and right pulmonary arteries. Pulmonary arterial hypertension is an uncommon complication following arterial switch procedure.

L-Transposition of Great Arteries L-Transposition of Great Arteries Jonathan Hero Chung, MD Key Facts Terminology  Synonym: Congenitally corrected transposition of great arteries (misnomer) o Most patients have concomitant congenital abnormalities Imaging  Inversion of ventricles and great arteries: Atrioventricular (AV) and ventriculoarterial discordance  Great vessels lie parallel and almost in same coronal plane; aortic valve anterior and slightly to the left (Lloop) of pulmonary valve  Hemodynamics o Right atrium → mitral valve → right-sided morphologic left ventricle → pulmonary circulation o Left atrium → tricuspid valve → left-sided morphologic right ventricle → systemic circulation  Echocardiography allows for complete preoperative diagnosis in majority of cases  CT or MR are complementary noninvasive cross-sectional tests for more complex abnormalities Pathology  Concomitant ventricular septal defect (VSD): 80% Clinical Issues  Most common presentation o Heart failure (VSD, systemic AV valve dysfunction) o Cyanosis (subpulmonary stenosis)  Incidence: 1 in 13,000 live births, 1% of congenital heart disease, M > F  Prognosis: Determined by presence of AV valve dysfunction  Surgical treatment focuses on associated abnormalities

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(Left) Graphic of levo transposition of great arteries (L-TGA) shows a left-sided aorta that is connected to a leftsided morphological right ventricle. The right-sided pulmonary artery is connected to right-sided left ventricle. There is a high ventricular septal defect (VSD) . (Right) Axial oblique MRA shows the left ventricle pumping blood into the pulmonary arterial system . The right ventricle is recognized by its partially visualized moderator band .

(Left) Axial CTA image shows abnormal location of the ascending aorta , anterior and to the left of the pulmonary artery , consistent with L-TGA. (Right) Axial CTA image from the same patient shows a markedly dilated left-sided morphologic right ventricle (identified by the moderator band and a large amount of trabeculation) and systemic atrium . Dilation of the systemic atrium and ventricle from ventricular failure is not uncommon in L-TGA. P.2:41

TERMINOLOGY Abbreviations  Levo transposition of great arteries (L-TGA)  L = levo = left Synonyms  Congenitally corrected transposition of great arteries (misnomer) o Most patients have concomitant congenital abnormalities  Discordant transposition  Ventricular inversion Definitions  Inversion of ventricles and great arteries: Atrioventricular (AV) and ventriculoarterial discordance 130

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Ebstein anomaly: Displacement of tricuspid valve into right ventricle (RV) Segmental approach to congenital heart disease (3 steps) o Visceroatrial situs: Atria relative to nearby anatomy  Situs solitus (S): Normal  Situs inversus (I): Inverted  Situs ambiguus (A): Ambiguous o Ventricular topology: Orientation of ventricular loop  Dextro-loop (D): Rightward  Levo-loop (L): Leftward o Great arterial position  Solitus (S): Normal  Inversus (I): Inverted  L-transposition (L)  D-transposition (D) IMAGING General Features  Best diagnostic clue o Great vessels lie parallel and almost in same coronal plane; aortic valve anterior and slightly to the left (L-transposed) of pulmonic valve  Location o Hemodynamics  Right atrium → mitral valve → right-sided morphologic left ventricle (LV) → pulmonary circulation  Left atrium → tricuspid valve → left-sided morphologic RV → systemic circulation  Hemodynamics dependent on associated anomalies  Morphology o {S, L, L} heart  Atrial situs solitus, L-loop, L-transposed great arteries  Right-sided morphologic LV characterized by associated mitral valve, smooth wall, and absent outflow chamber to pulmonary valve  Left-sided morphologic RV characterized by tricuspid valve, trabeculated wall, moderator band, and infundibulum below aortic valve o {I, D, D} heart  Atrial situs inversus, D-loop, D-transposed great arteries  Mirror image of {S, L, L} heart  Almost always associated with cardiac malposition: Mesocardia, dextroversion, true dextrocardia (25%) Radiographic Findings  Radiography o Variable o Dextrocardia (25% of cases) o Classic: Straight upper left heart border o Other findings from associated anomalies CT Findings  Best test to evaluate coronary artery morphology and course  Aortic valve is anterior and to the left of pulmonic valve  L-transposition can be imaged in detail with CTA; however, radiation concerns make it 2nd-line alternative to MR  Gated low-dose CTA can be used for ventricular function evaluation  3D and multiplanar reformats depict abnormal atrioventricular and ventriculoarterial relationships MR Findings  T1WI o Multiplanar cardiac-gated T1WI and 3D gadolinium MRA for segmental cardiac analysis and anatomic evaluation o MRA for coronary ostia and course  Dobutamine stress short-axis steady-state free precession cine MR for functional evaluation of RV Echocardiographic Findings  Echocardiogram o Segmental cardiac analysis: Identification of atria, ventricles, great arteries, and their connections 131

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Continuity between right-sided mitral and pulmonary valve annuli Discontinuity between atrioventricular and aortic valve annuli (separated by muscular ring) defines systemic ventricle as the morphological RV and therefore AV valve as tricuspid valve o Abnormally straight, vertical course of interventricular septum o Coronary ostia assessed on short axis imaging of cardiac base Imaging Recommendations  Protocol advice o Echocardiography allows for complete preoperative diagnosis in majority of cases o CT and MR are complementary noninvasive cross-sectional tests for more complex abnormalities  MR: Preferred over CT given radiation risks  CT: Best test to define coronary anatomy DIFFERENTIAL DIAGNOSIS Congestive Heart Failure, Increased Pulmonary Blood Flow  Isolated ventricular septal defect (VSD)  Double inlet ventricle  Tricuspid atresia with increased pulmonary blood flow  Double outlet right ventricle with subaortic VSD P.2:42

Cyanosis, Decreased Pulmonary Blood Flow  Tetralogy of Fallot Atrioventricular Discordance With Ventriculoarterial Concordance  Isolated ventricular inversion, with each ventricle connected to its appropriate great artery, and physiology resembling D-transposition PATHOLOGY General Features  Genetics o No genetic factors or chromosomal abnormalities o Not commonly associated with significant extracardiac malformations  Associated abnormalities o VSD: 80% of cases o LV outflow tract (subpulmonary) obstruction: 30% o Left-sided tricuspid valve dysplasia, Ebstein anomaly, regurgitation: 30% o Can be associated with atrial situs inversus: Dextrocardia {I, D, D} o Rare: Ventricular hypoplasia, AV canal, straddling AV valves, aortic atresia, coarctation, or interruption  Ventricular arrangement is not simply mirror image of normal  Ventricles and great arteries form L-loop  Interventricular septum is more vertical in orientation than normal  Coronary distribution is mirror image of normal distribution (right-sided coronary artery bifurcates into circumflex and anterior descending arteries)  Embryology: Primitive cardiac tube loops to the left (L-loop), leading to ventricular inversion and left-sided position of ascending aorta  Pathophysiology o Determined by associated anomalies: VSD, subpulmonary stenosis, AV valve dysfunction o Late sequel: Left-sided RV is not able to sustain systemic circulation Gross Pathologic & Surgical Features  Right-sided morphologic LV connected without infundibulum to pulmonic valve, which is posterior and to the right of aortic valve  Infundibulum of systemic morphologic RV connected to aortic valve, which is slightly anterior and to the left of pulmonic valve (L-loop)  Pulmonary artery and ascending aorta lie nearly parallel in coronal plane  Interruption of conduction system of heart due to malalignment between atrial and ventricular septa: Disconnection between atrioventricular node and bundle of His → 3rd-degree heart block CLINICAL ISSUES Presentation  Most common signs/symptoms 132

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Heart failure (VSD, systemic AV valve dysfunction) Cyanosis (subpulmonary stenosis) Rarely completely asymptomatic, often presenting as incidental finding on chest radiograph (straight upper left heart border)  Other signs/symptoms o Conduction disturbances: Bradycardia (heart block) and tachydysrhythmia o Decreased exercise tolerance due to dysfunction of systemic ventricle (morphologic RV) Demographics  Epidemiology o Incidence: 1 in 13,000 live births o 1% of congenital heart disease o Males > females Natural History & Prognosis  Determined by presence of AV valve dysfunction  Guarded prognosis due to progressive systemic AV valve and RV dysfunction: 50% mortality rate after 15 years  Patients with true congenitally corrected transposition may have normal life expectancy Treatment  Surgical treatment focuses on associated abnormalities o Congestive heart failure from VSD shunt: PA banding or VSD closure o Cyanosis from subpulmonary stenosis: Systemic to PA shunt (Blalock) or LV to PA conduit (Rastelli) o Pulmonary venous hypertension from tricuspid valve dysfunction: Tricuspid valvuloplasty  Double-switch operation to prevent late systemic ventricular (RV) failure o Venous switch (Senning) reroutes atrial blood into appropriate ventricles o Ventricular (Rastelli) or arterial switch: Morphologic LV becomes systemic ventricle  Pacemaker insertion SELECTED REFERENCES 1. Wallis GA et al: Congenitally corrected transposition. Orphanet J Rare Dis. 6:22, 2011 2. Cohen MD et al: MRI of surgical repair of transposition of the great vessels. AJR Am J Roentgenol. 194(1):250-60, 2010 3. Hornung TS et al: Congenitally corrected transposition of the great arteries. Heart. 96(14):1154-61, 2010 4. Lapierre C et al: Segmental approach to imaging of congenital heart disease. Radiographics. 30(2):397-411, 2010 5. Martins P et al: Transposition of the great arteries. Orphanet J Rare Dis. 3:27, 2008 6. Skinner J et al: Transposition of the great arteries: from fetus to adult. Heart. 94(9):1227-35, 2008 7. Chang DS et al: Congenitally corrected transposition of the great arteries: imaging with 16-MDCT. AJR Am J Roentgenol. 188(5):W428-30, 2007 8. Dorfman AL et al: Magnetic resonance imaging evaluation of congenital heart disease: conotruncal anomalies. J Cardiovasc Magn Reson. 8(4):645-59, 2006 9. Kantarci M et al: Congenitally corrected transposition of the great arteries: MDCT angiography findings and interpretation of complex coronary anatomy. Int J Cardiovasc Imaging. 2006 10. Mohrs OK et al: Time-resolved contrast-enhanced MR angiography of the thorax in adults with congenital heart disease. AJR Am J Roentgenol. 187(4):1107-14, 2006 11. Warnes CA: Transposition of the great arteries. Circulation. 114(24):2699-709, 2006 P.2:43

Image Gallery

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(Left) Axial oblique cardiac CT shows normal anatomy of the superior aspect of the heart. The right ventricle can be identified by a complete muscular infundibulum that separates the atrioventricular and semilunar valves. (Right) Three-chamber cardiac CT image shows continuity of the anterior mitral valve leaflet and the aortic valve apparatus, typical of a normal left ventricle. This finding is especially helpful in distinguishing between the morphologic right and left ventricles.

(Left) Four-chamber cardiac CT image shows a normal left atrium receiving pulmonary venous inflow . However, the left atrium empties into the anatomic right ventricle, which can be recognized by its increased trabeculation and moderator band . (Right) Right ventricular outflow tract view shows the morphologic right ventricle draining into the aorta . The morphologic right ventricle shows separation of the inflow valve plane and outflow tract by an infundibulum .

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(Left) Axial CECT shows the typical location of the ascending aorta in L-TGA (i.e., anterior and to the left of the pulmonary artery ). In normal patients, the ascending aorta should be at relatively the same AP level as the pulmonary artery. (Right) Axial CECT image shows a severely dilated left-sided morphologic right ventricle (as suggested by the large degree of trabeculation ). Failure of the morphologic right ventricle is common in L-TGA given the chronic exposure to systemic arterial pressure.

Truncus Arteriosus Truncus Arteriosus Brett W. Carter, MD Key Facts Terminology  Common arterial vessel arising from heart o Gives rise to aorta, pulmonary arteries (PAs), and coronary arteries  Category: Cyanotic, cardiomegaly, and increased pulmonary vascularity Imaging  Classic radiographic appearance: Cardiomegaly, right aortic arch, narrow mediastinum, and increased pulmonary vascularity  Diagnosis typically made with echocardiography  MR/CTA for preoperative delineation of anatomy  MR/CTA for postoperative assessment of conduit and stents Top Differential Diagnoses  D-transposition; L-transposition  Hypoplastic left heart syndrome Pathology  Strong association with chromosome 22q11.2 (DiGeorge) syndrome Clinical Issues  2% of all congenital cardiac anomalies  Most common congenital heart condition associated with right aortic arch  Symptoms include progressive congestive heart failure and increasing cyanosis  Treatment o Early complete repair (at 2-6 weeks of life) is favored o PAs detached from arterial trunk and conduit placed between PAs and right ventricle; patch closure of VSD o Complications: Conduit stenosis or regurgitation, branch PA stenosis, truncal stenosis or regurgitation o Conduit revisions ± replacement usually necessary

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(Left) Graphic demonstrates a type 1 truncus giving rise to the aorta and main pulmonary artery. Note the common truncal valve and overriding a high ventricular septal defect. A right aortic arch is present. (Right) Anteroposterior chest radiograph of a patient status post repair of truncus arteriosus shows cardiomegaly and a dual-chamber pacemaker. Cardiac arrhythmias, including heart block, may complicate truncus arteriosus and necessitate pacemaker placement.

(Left) Coronal CTA of a patient with truncus arteriosus demonstrates the truncal valve overriding both the right ventricle and left ventricle. Note the right aortic arch. (Right) Coronal CTA shows a common trunk giving rise to a right-sided aortic arch and pulmonary artery . P.2:45

TERMINOLOGY Abbreviations  Truncus arteriosus (TA) Definitions  Common arterial vessel arising from heart o Gives rise to aorta, pulmonary arteries (PAs), and coronary arteries  Category: Cyanotic, cardiomegaly, and increased pulmonary vascularity  Hemodynamics o Both ventricles are connected to pulmonary and systemic circulations o Flow admixture across ventricular septal defect (VSD) and within truncus → cyanosis o Postnatal drop in pulmonary vascular resistance → relative increase in pulmonary blood flow → volume overload of pulmonary circulation 136

Diagnostic Imaging Cardiovascular IMAGING General Features  Best diagnostic clue o Common arterial trunk arising from both ventricles o Classic radiographic appearance: Cardiomegaly, right aortic arch, narrow mediastinum, and increased pulmonary vascularity Radiographic Findings  Radiography o Cardiomegaly o Right aortic arch o Narrow mediastinum due to thymic agenesis o Increased pulmonary vascularity o Atelectasis  Dilated PAs may compress neighboring bronchi CT Findings  CTA o Preoperative  Common arterial trunk arising from both ventricles  Relationship of branch PAs to truncus  Evaluate coronary anatomy o Postoperative  Evaluate conduit, stents  Patency and size  Presence of calcification, stenosis MR Findings  MRA o Evaluate global anatomy, patency of conduit  MR cine o Steady-state free precession (SSFP) cine MR  Truncal valve regurgitation  Ventricular function  General o Common arterial trunk arising from both ventricles o More effective than echocardiography in the evaluation of  Branch PAs  Aortopulmonary collateral vessels  Complex abnormalities involving aortic arch or pulmonary veins o Evaluate for postoperative complications Echocardiographic Findings  Echocardiogram o Typically used for diagnosis and surgical planning o Common arterial trunk originating from both ventricles o High (outlet) VSD immediately below truncal valve o Common truncal valve with 2 (5%), 3 (60%), or 4 (25%) cusps  Color Doppler o Bidirectional flow across VSD o Truncal valve regurgitation Angiographic Findings  Conventional o Cardiac catheterization with angiography  Define truncal anatomy  Evaluate truncal valve insufficiency  Hemodynamic study is gold standard for calculation of pulmonary vascular resistance Imaging Recommendations  Protocol advice o Diagnosis typically made with echocardiography o MR/CTA for preoperative delineation of anatomy o MR/CTA for postoperative assessment of conduit, stents DIFFERENTIAL DIAGNOSIS 137

Diagnostic Imaging Cardiovascular D-Transposition  Atrioventricular concordance and ventriculoarterial discordance  Category: Cyanotic, cardiomegaly, and increased pulmonary vascularity  Best diagnostic clues o Aorta and pulmonary trunk lie parallel o Aortic valve located to the right of and anterior to pulmonary valve L-Transposition  Atrioventricular and ventriculoarterial discordance  Category: Dependent on associated anomalies o Left ventricular outflow tract (subpulmonic) obstruction: Cyanotic o VSD: Acyanotic Hypoplastic Left Heart Syndrome  Hypoplasia/atresia of the ascending aorta, aortic valve, left ventricle (LV), and mitral valve  Most severe congenital heart lesion presenting in neonatal period with congestive heart failure, cardiogenic shock, and cyanosis  Category: Cyanotic, cardiomegaly, and increased pulmonary vascularity  Best diagnostic clue: Hypoplasia of ascending aorta, LV PATHOLOGY General Features  Etiology o Embryology  Lack of separation of primitive bulbus cordis into aorta and main PA  Associated persistence of primitive aortic arches o Pathophysiology P.2:46 

Congestive heart failure vs. cyanosis (degree of cyanosis is determined by balance of pulmonary and systemic resistance)  Marked increase in pulmonary blood flow in early neonatal period due to drop in pulmonary vascular resistance → slight improvement in cyanosis but worsening congestive heart failure  Development of pulmonary vascular obstructive disease leads to improvement in congestive heart failure but worsening cyanosis

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Genetics o Strong association with chromosome 22q11.2 (DiGeorge) syndrome o CATCH-22: Conofacial anomaly, absent thymus, hypocalcemia, heart defect o Velocardiofacial (Shprintzen) syndrome  Associated abnormalities o Malalignment VSD present in almost all cases o Right aortic arch o Interrupted aortic arch (11-14%) o Atrial septal defect o Aberrant subclavian artery o Left superior vena cava o Other  Abnormalities of mitral valve, coronary arteries, pulmonary veins Staging, Grading, & Classification  Collett and Edwards classification system o Type 1: PAs arise from a short pulmonary trunk o Type 2: PAs arise separately from posterior aspect of truncus o Type 3: PAs arise separately from lateral aspect of truncus o Type 4: Pseudotruncus with ventricular septal defect; considered to be form of pulmonary atresia  Van Praagh classification o Type A1: Same as Collett and Edwards type 1 o Type A2: Same as Collett and Edwards type 2 o Type A3: Unilateral pulmonary artery with collateral supply to ipsilateral lung o Type A4: Truncus with interrupted aortic arch Gross Pathologic & Surgical Features 138

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Position of common trunk with respect to VSD o Positioned over right ventricle (RV) (42%) o Positioned over left ventricle (16%) o Equally shared (42%) CLINICAL ISSUES Presentation  Most common signs/symptoms o Progressive congestive heart failure in young infant o Increasing cyanosis  Other signs/symptoms o T-cell immunodeficiency (thymic agenesis in DiGeorge syndrome) o Neonatal tetany (absent parathyroid glands in DiGeorge syndrome) Demographics  Epidemiology o 2% of all congenital cardiac anomalies o 94 per 1,000,000 live births o Most common congenital heart condition associated with right aortic arch Natural History & Prognosis  Mortality if untreated o 6 months: 65%; 12 months: 75%  Intractable congestive heart failure o Marked increase in pulmonary flow after drop in pulmonary vascular resistance o Aggravated by presence of truncal valve regurgitation (in 50% of cases)  Eventual shunt reversal with progressive cyanosis and sudden death o Pulmonary vascular obstructive disease with Eisenmenger physiology can develop as early as 6 months of age  Postoperative course determined by function of conduit and morbidity of conduit replacement Treatment  Palliative: Banding of main PA o Initial palliation with PA banding often unsatisfactory  Early development of pulmonary arterial hypertension  Surgical repair o Patch closure of VSD o Coarctation of the aorta and interruption corrected o Early complete repair (at 2-6 weeks of life) is favored by most surgeons  PAs detached from arterial trunk and conduit placed between PAs and RV  Complications  PA-RV conduit stenosis or regurgitation  Branch PA stenosis  Neoaortic valve (truncal) stenosis or regurgitation  VSD patch leak  Obstruction of aortic arch  Conduit revisions ± replacement usually necessary  Patient outgrows fixed conduit size  Stenosis, neointimal hyperplasia  Anastomotic pseudoaneurysm  Calcification  Conduit valve dysfunction SELECTED REFERENCES 1. Frank L et al: Cardiovascular MR imaging of conotruncal anomalies. Radiographics. 30(4):1069-94, 2010 2. François CJ et al: Unenhanced MR angiography of the thoracic aorta: initial clinical evaluation. AJR Am J Roentgenol. 190(4):902-6, 2008 3. Gaca AM et al: Repair of congenital heart disease: a primer—Part 2. Radiology. 248(1):44-60, 2008 4. Gaca AM et al: Repair of congenital heart disease: a primer—part 1. Radiology. 247(3):617-31, 2008 5. Dorfman AL et al: Magnetic resonance imaging evaluation of congenital heart disease: conotruncal anomalies. J Cardiovasc Magn Reson. 8(4):645-59, 2006 6. Rajasinghe HA et al: Long-term follow-up of truncus arteriosus repaired in infancy: a twenty-year experience. J Thorac Cardiovasc Surg. 113(5):869-78; discussion 878-9, 1997 P.2:47 139

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Image Gallery

(Left) Axial GRE MR image shows a common arterial trunk arising from both ventricles . (Right) Axial GRE MR image of the same patient demonstrates dilation of the truncus secondary to truncal valve dysfunction (regurgitation), which may necessitate valvuloplasty or placement of a prosthesis. Truncus arteriosus represents a lack of separation of the primitive bulbus cordis into the aorta and the main pulmonary artery.

(Left) Posteroanterior chest radiograph of a patient with truncus arteriosus demonstrates a right aortic arch . (Right) Axial CECT of the same patient shows the right aortic arch . Truncus arteriosus is the most common congenital heart condition associated with a right aortic arch. Other anomalies such as atrial septal defect, aberrant subclavian arteries, and left superior vena cava may be present.

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(Left) Posteroanterior chest radiograph demonstrates a calcified PA conduit following truncus repair. Note right aortic arch . Common complications following conduit placement include conduit stenosis or regurgitation, branch PA stenosis, & truncal stenosis or regurgitation. Conduit revisions ± replacement are often necessary. (Right) Posteroanterior chest radiograph post surgical repair of truncus arteriosus shows cardiomegaly & a dual-chamber epicardial pacemaker.

Pulmonary Atresia Pulmonary Atresia Brett W. Carter, MD Key Facts Terminology  Congenital malformation characterized by failed development of pulmonary valve orifice  2 distinct types based upon status of interventricular septum  Category: Cyanotic, cardiomegaly, decreased ± irregular pulmonary vascularity Imaging  Best diagnostic clue: RVOT ± pulmonary valve atresia  Chest radiography: Extreme “boot-shaped” configuration of heart o Right aortic arch is common  Initial diagnosis with echocardiography  CT or MR for assessment of pulmonary artery anatomy, postoperatively for shunt/conduit patency  Cardiac catheterization for hemodynamic assessment, selective injection studies, and catheter-based interventions Top Differential Diagnoses  Ebstein anomaly  Tetralogy of Fallot with pulmonary atresia  Tricuspid atresia with VSD Clinical Issues  Progressive cyanosis after birth with closure of ductus arteriosus  Congestive heart failure with large and unobstructed high-flow multiple aortopulmonary collateral arteries  Prognosis depends on feasibility of surgery  Treatment o Prostaglandin E1 to keep ductus arteriosus open o Management of congestive heart failure o Pulmonary atresia with VSD: Staged complete repair o Pulmonary atresia with intact ventricular septum: Type of repair depends on RV size and RV dependency on coronary circulation

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(Left) Graphic demonstrates pulmonary atresia with intact ventricular septum (PA-IVS). A patent foramen ovale is present. Note right atrial dilation and right ventricular hypertrophy. The pulmonary arteries are perfused via a patent ductus arteriosus. (Right) Posteroanterior chest radiograph of a patient with pulmonary atresia with ventricular septal defect (PA-VSD) shows an extreme “boot-shaped” configuration of the heart. A right aortic arch is present.

(Left) Axial CTA of a patient with PA-VSD shows multiple aortopulmonary collateral arteries (MAPCAs) originating from the descending thoracic aorta. (Right) 3D reconstruction in the same patient demonstrates the MAPCAs . MAPCAs most commonly originate from the descending thoracic aorta but may also arise from the ascending thoracic aorta, subclavian or intercostal arteries, or ductus arteriosus. P.2:49

TERMINOLOGY Abbreviations  Pulmonary atresia with ventricular septal defect (PA-VSD)  Pulmonary atresia with intact ventricular septum (PA-IVS) Synonyms  Pseudotruncus, truncus arteriosus type 4 Definitions  Congenital malformation characterized by failed development of pulmonary valve orifice  2 distinct types based upon status of interventricular septum o PA-VSD, multiple aortopulmonary collateral arteries (MAPCAs): Hypoplastic/absent pulmonary arteries (PAs); MAPCAs supply 1 or both lungs o PA-IVS: Normal-sized PAs supplied by ductus arteriosus, patent foramen ovale (PFO) 142

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Both entities are characterized by underdevelopment of right ventricular outflow tract (RVOT) and pulmonary valve o PA-VSD, MAPCAs: At extreme end of spectrum of RVOT-obstructive (Fallot-type) heart lesions, with complex and highly variable PA anatomy  Category: Cyanotic, cardiomegaly, decreased ± irregular pulmonary vascularity  Hemodynamics o Extreme outflow obstruction of right ventricle (RV) o Majority of cardiac output goes into dilated overriding ascending aorta IMAGING General Features  Best diagnostic clue o Atresia of RVOT ± pulmonary valve Radiographic Findings  Radiography o Extreme “boot-shaped” configuration of heart o PA-IVS: Massive right atrial dilation o Right aortic arch is common o Diminutive hila o Irregular branching patterns of MAPCAs CT Findings  CTA o Better than echocardiography for PA anatomy o Evaluate patency of shunts/conduits postoperatively MR Findings  T1WI o PA-VSD, MAPCAs: Cardiac-gated axial images for preoperative delineation of PA anatomy  T2* GRE o Short- and long-axis steady-state free precession (SSFP) cine MR for functional assessment, tricuspid regurgitation  MRA o Coronal gadolinium-enhanced MRA for detailed analysis of PA anatomy and MAPCAs Echocardiographic Findings  Echocardiogram o PA-VSD, MAPCAs  Characteristics of intracardiac anatomy, position and size of VSD, overriding aortic root  Development of branch PAs, confluence o PA-IVS  Morphology of interatrial septum  Evaluate for restricted flow across PFO  Size of RV and tricuspid annulus (expressed as a “z-score”), degree of tricuspid regurgitation  Important for surgical planning Angiographic Findings  Conventional o PA-VSD, MAPCAs  Selective injection with pressure recordings of all MAPCAs, imaging of true PAs  Pulmonary venous wedge injections for retrograde filling of diminutive PAs o PA-IVS  Suprasystemic pressure recordings in RV  Detailed imaging of coronary anatomy through RV and aortic root injections: RV to coronary artery communications, stenoses, interruptions Imaging Recommendations  Protocol advice o PA-VSD, MAPCAs  Initial diagnosis with echocardiography  CT or MR for assessment of PA anatomy, postoperatively for shunt/conduit patency  Cardiac catheterization for hemodynamic assessment, selective injection studies, and catheter-based interventions DIFFERENTIAL DIAGNOSIS Ebstein Anomaly 143

Diagnostic Imaging Cardiovascular  May mimic PA-IVS with large tricuspid annulus and massive tricuspid regurgitation Tetralogy of Fallot With Pulmonary Atresia  Pseudotruncus arteriosus  Complete RVOT atresia; absence of pulmonary trunk  Blood flow: RV → left ventricle → aorta Tricuspid Atresia With VSD  Muscular or membranous partition between right atrium and RV  Obligatory shunting from right atrium → left atrium → left ventricle → RV  Decreased pulmonary flow → severe cyanosis at birth  When associated with transposition, there is increased pulmonary blood flow PATHOLOGY General Features  Etiology o Embryology  PA-VSD, MAPCAs  Persistence or hypertrophy of primitive arterial connections to lungs  RVOT obstruction → hypoplasia of PAs P.2:50  Hypertrophy of bronchial arteries Pathophysiology of PA-VSD, MAPCAs  Balance between flow though PAs and MAPCAs determines pulmonary perfusion  PA flow at subsystemic pressures, restricted by narrow caliber and eventual closure of ductus arteriosus  Flow through MAPCAs leads to increased lung perfusion at systemic pressures (unless restricted by stenosis)  Degree of cyanosis is determined by intracardiac admixture and amount of pulmonary flow  Large amount of pulmonary blood flow through unrestricted MAPCAs → congestive heart failure o Pathophysiology of PA-IVS  Obligatory right → left shunt through PFO  Pulmonary arteries supplied by PDA  Small heavily trabeculated right ventricle with suprasystemic pressures  Depending on size of tricuspid valve annulus: Severe tricuspid regurgitation, leading to massive right atrial dilatation (comparable to Ebstein)  Transmyocardial sinusoids connecting right ventricular cavity with coronary artery system cause coronary flow reversal during diastole, leading to myocardial ischemia and infarction  Associated abnormalities o Aortic stenosis o Ebstein anomaly o Proximal pulmonary artery atresia o Right aortic arch o Tricuspid atresia Staging, Grading, & Classification  Tchervenkov and Roy classification of PA-VSD o Type A: Only native PAs o Type B: Pulmonary blood flow via both native PAs and MAPCAs o Type C: Only MAPCAs, no native PAs  Classification of PA-IVS o Type I: Pulmonary valvular atresia, tricuspid valve competence, and intact ventricular septum o Type II: Proximal pulmonary artery atresia, tricuspid valve incompetence, and intact ventricular septum Gross Pathologic & Surgical Features  Presence and confluence of central portions of true PAs is important for surgical repair  Possible origins of MAPCAs o Ascending thoracic aorta o

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Diagnostic Imaging Cardiovascular o Descending thoracic aorta (most common) o Ductus arteriosus o Subclavian or intercostal arteries Microscopic Features  Pulmonary vascular disease develops in vascular bed of high-flow MAPCAs → increase in cyanosis CLINICAL ISSUES Presentation  Most common signs/symptoms o Progressive cyanosis after birth with closure of ductus arteriosus o Congestive heart failure with large and unobstructed high-flow MAPCAs  Other signs/symptoms o Failure to thrive, polycythemia, and clubbing Demographics  Epidemiology o PA-VSD: 2.5-3.4% of congenital cardiac anomalies o PA-IVS: 0.7-3.1% of congenital cardiac anomalies  7.1-8.1 per 100,000 live births in United States Natural History & Prognosis  Progressive cyanosis o Development of pulmonary vascular disease → irreversible pulmonary hypertension  Life expectancy < 10 years if untreated  Increased survival into adulthood  Prognosis depends on feasibility of surgery Treatment  Prostaglandin E1 to keep ductus arteriosus open  Management of congestive heart failure  Palliative o Systemic-to-PA shunt (Blalock-Taussig) o Initial banding of high-flow MAPCAs  PA-VSD: Staged complete repair o Unifocalization of MAPCAs and true PAs o Early 1-stage repair in infancy with incorporation of all MAPCAs in PA conduit o Complete repair with incorporation of MAPCAs and PAs in conduit, connected to reconstructed RVOT, closure of VSD  High pressure in pulmonary system from residual stenosis/hypoplasia and pulmonary vascular disease limit feasibility o Catheter-based interventions  Balloon angioplasty with stenting of stenoses, coil embolization of small superfluous &/or bleeding MAPCAs  PA-IVS: Type of repair dependent on RV size and RV dependency on coronary circulation o Restricted flow across PFO: Balloon atrial septostomy o Catheter-based or surgical pulmonary valvotomy o RV too hypoplastic for biventricular repair: Cavopulmonary (Glenn) shunt, staged completion of univentricular repair (Fontan) o Complications  Sudden decompression of RV through valvotomy, RVOT repair, or transannular patch may lead to myocardial ischemia/infarction SELECTED REFERENCES 1. Frank L et al: Cardiovascular MR imaging of conotruncal anomalies. Radiographics. 30(4):1069-94, 2010 2. Rajeshkannan R et al: Role of 64-MDCT in evaluation of pulmonary atresia with ventricular septal defect. AJR Am J Roentgenol. 194(1):110-8, 2010 3. François CJ et al: Unenhanced MR angiography of the thoracic aorta: initial clinical evaluation. AJR Am J Roentgenol. 190(4):902-6, 2008 4. Gaca AM et al: Repair of congenital heart disease: a primer—Part 2. Radiology. 248(1):44-60, 2008 5. Gaca AM et al: Repair of congenital heart disease: a primer—part 1. Radiology. 247(3):617-31, 2008 P.2:51

Image Gallery 145

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(Left) Axial CTA of a patient with PA-VSD shows a right aortic arch . Abnormalities that may be associated with PAVSD include aortic stenosis, Ebstein anomaly, proximal pulmonary artery atresia, right aortic arch, and tricuspid atresia. (Right) Axial CTA of the same patient demonstrates MAPCAs arising from the descending aorta. MAPCAs supplying 1 or both lungs develop as a result of hypoplastic or absent pulmonary arteries. Large, unobstructed MAPCAs may result in congestive heart failure.

(Left) Posteroanterior chest radiograph of a patient with PA-IVS shows cardiomegaly. The marked dilation of the right atrium resembles Ebstein anomaly. PA-IVS is characterized by an obligatory right-to-left shunt through a patent foramen ovale (PFO), and the pulmonary arteries are supplied by a patent ductus arteriosus (PDA). (Right) Coronal CTA shows a right aortic arch and a prominent aortopulmonary collateral artery supplying the left lung.

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(Left) Axial GRE MR demonstrates an aortopulmonary collateral artery originating from the left aspect of the descending thoracic aorta and extending into the left lung. (Right) Coronal GRE MR of the same patient shows the presence of MAPCAs arising from the descending thoracic aorta. Although initial diagnosis of PA-VSD is typically made by echocardiography, MR is beneficial for the delineation of PA anatomy and evaluating the patency of shunts/conduits following surgery.

Hypoplastic Left Heart Syndrome Hypoplastic Left Heart Syndrome Jonathan Hero Chung, MD Key Facts Terminology  Hypoplasia/atresia of ascending aorta, aortic valve, left ventricle (LV), and mitral valve Imaging  Radiography o Cardiomegaly o Pulmonary venous congestion with interstitial fluid  CT or MR o Atresia or hypoplasia of ascending aorta and LV o Severe obstruction of flow to systemic circulation (ductus dependent) o Retrograde flow in hypoplastic aortic arch and ascending aorta for cranial and coronary perfusion o Volume overload in pulmonary circulation o Left-to-right shunting through patent foramen ovale  Echocardiogram or MR o Prenatal diagnosis commonly made Top Differential Diagnoses  Critical aortic stenosis, infantile coarctation, interrupted aortic arch Pathology  Due to abnormal partitioning of primitive conotruncus into left and right ventricular outflow tracts → hypoplasia/atresia of aortic valve Clinical Issues  Cyanosis (flow admixture in right heart)  Cardiogenic shock after closure of patent ductus arteriosus  Congestive heart failure (volume overload pulmonary circulation)  Treatment: Prostaglandin E1 to keep patent ductus arteriosus open, palliative surgical repair, cardiac transplantation

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(Left) Graphic shows hypoplasia of the left atrium, left ventricle, aortic valve, and ascending aorta. The systemic flow depends on the patency of the ductus arteriosus . (Right) Radiograph during the 1st day of life shows cardiomegaly, vascular congestion, and hyperinflation typical in patients with hypoplastic left heart syndrome. Endotracheal tube projects over the thoracic trachea, and the umbilical venous catheter extends into the right atrium.

(Left) Axial image from CTA of the chest shows hypoplastic ascending aorta and a relatively larger descending aorta . (Right) The main pulmonary artery is enlarged with a large patent ductus arteriosus . Again, the descending thoracic aorta is much larger than the hypoplastic ascending aorta . The descending thoracic aorta is perfused by the enlarged patent ductus arteriosus. P.2:53

TERMINOLOGY Abbreviations  Hypoplastic left heart syndrome (HLHS) Synonyms  Aortic atresia Definitions  Hypoplasia/atresia of ascending aorta, aortic valve, left ventricle (LV), and mitral valve o Secondary findings: Patent ductus arteriosus (PDA), juxtaductal coarctation  Most severe congenital heart lesion presenting in neonatal period with congestive heart failure, cardiogenic shock, and cyanosis  Category: Cyanotic, cardiomegaly, increased pulmonary vascularity 148

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Hemodynamics o Severe obstruction of flow to systemic circulation (ductus dependent) o Retrograde flow in hypoplastic aortic arch and ascending aorta for cranial and coronary perfusion o Volume overload in pulmonary circulation o Left-to-right shunting through patent foramen ovale o Flow admixture in right atrium → severe cyanosis IMAGING General Features  Best diagnostic clue o Hypoplasia of ascending aorta and left ventricle Radiographic Findings  Radiography o Cardiomegaly o Pulmonary venous congestion with interstitial fluid o Hyperinflation o Narrow mediastinum due to thymic atrophy CT Findings  CTA o Patency of aortopulmonary (Blalock-Taussig) and cavopulmonary (Glenn) shunts o Seroma associated with Blalock-Taussig shunt o Airway compression by dilated neoaortic arch following Norwood repair MR Findings  T2* GRE o Short-axis steady-state free precession (SSFP) cine MR for functional assessment of univentricular heart to determine suitability for Fontan operation o SSFP cine MR for ventricular volume measurements in marginally hypoplastic left heart to determine feasibility of biventricular repair  MRA o Velocity-encoded phase contrast (PC) MRA for measurements of flow through aortic isthmus, PDA, and foramen ovale  Can predict response to intraoperative test closure of ASD and PDA to determine feasibility of biventricular repair Echocardiographic Findings  Echocardiogram o HLHS increasingly diagnosed prenatally  Retrograde flow in diminutive ascending aorta  LV growth arrest becomes manifest between 18-22 weeks of gestation o Postnatal diagnosis with echo sufficient for treatment planning  Diminutive ascending aorta < 5 mm  Small, thick-walled LV  Mitral valve size is expressed as Z-score: Important parameter to decide whether biventricular repair is possible in marginally hypoplastic LVs  Dilatation of right-sided chambers and pulmonary artery (PA)  Size and location of ductus arteriosus  Patency of foramen ovale or presence of atrial septal defect  Abnormal ventricular wall motion (ischemic damage, fibroelastosis)  Color Doppler o Hemodynamics of aortic root o Left-to-right shunt through foramen ovale o Tricuspid regurgitation Angiographic Findings  Conventional angiography o Cardiac catheterization with angiography  Can be done via umbilical artery catheter  Retrograde flow in hypoplastic ascending aorta, filling of pulmonary arteries via ductus arteriosus Other Modality Findings  CTA, MR: Occasionally performed after staged Norwood or Stansel procedures o Residual stenosis of neoaortic arch, coarctation 149

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Functional assessment of marginally hypoplastic left heart with cine MR and velocity-encoded PCMRA, prior to Fontan operation Imaging Recommendations  Primary diagnosis is made with echocardiography in majority of cases  Postoperative: Functional MR and interventional catheterizations for residua/sequelae of Fontan operation DIFFERENTIAL DIAGNOSIS Critical Aortic Stenosis, Infantile Coarctation, Interrupted Aortic Arch  Pressure overload of normally developed left ventricle Cranial (Vein of Galen) or Hepatic Arteriovenous Malformation  Structurally normal heart, volume overload of all chambers Cardiomyopathy, Endocardial Fibroelastosis  Globally enlarged, structurally normal heart, myocardial dysfunction Bland-White-Garland Syndrome  Left coronary originates from PA, LV infarction Severe Arrhythmias: Paroxysmal Supraventricular Tachycardia  Characteristic electrocardiogram P.2:54

PATHOLOGY General Features  Genetics o No clear genetic defect demonstrated in majority o Not commonly associated with extracardiac malformations  Underdevelopment of left-sided cardiac structures o Hypoplasia or atresia of aortic and mitral valves o Hypoplasia of LV and ascending aorta  Compatible with normal fetal hemodynamics → no fetal compromise  Embryology o Abnormal partitioning of primitive conotruncus into left and right ventricular outflow tracts → hypoplasia/atresia of aortic valve o Diminished prenatal antegrade flow through aorta → underdevelopment of LV and ascending aorta  Pathophysiology o Severe obstruction to outflow of diminutive LV o Pulmonary venous flow shunts through foramen ovale into right atrium o Dilated right-sided cardiac chambers and PA o Systemic perfusion via PDA Gross Pathologic & Surgical Features  Severe hypoplasia of left-sided cardiac chambers and ascending aorta  Large main pulmonary artery, ductus arteriosus  Localized aortic coarctation (80%)  Endocardial fibroelastosis in small, thick-walled LV CLINICAL ISSUES Presentation  Most common signs/symptoms o No circulatory symptoms immediately at birth but rapid deterioration  Congestive heart failure (volume overload pulmonary circulation)  Cardiogenic shock after closure of PDA  Cyanosis (flow admixture in right heart)  Hypoxia → pulmonary hypertension, persistent fetal circulation  Other signs/symptoms o Poor systemic perfusion, metabolic acidosis  Acute tubular necrosis, renal failure  Necrotizing enterocolitis Demographics  Epidemiology o 1-3 per 10,000 live births; M:F = 2:1 o 4th most common congenital heart lesion presenting at < 1 year of age (7-9%) 150

Diagnostic Imaging Cardiovascular Natural History & Prognosis  Death within days/weeks when untreated  Poor prognosis without treatment; has improved substantially in recent years  Determined by complications, residua and sequelae of staged Norwood repair and Fontan operation (right ventricular dysfunction, venous hypertension)  Significant tricuspid regurgitation after surgical palliation correlates with poor outcome Treatment  Medical: Prostaglandin E1 to keep PDA open  Prenatal: US-guided balloon dilatation of aortic valve in mid/late fetal period is now possible o Change in fetal hemodynamics may enhance prenatal growth of left-sided cardiac structures  Rashkind balloon atrial septostomy (in case of flow restriction across foramen ovale)  Palliative repair o Norwood: Atrial septectomy, construction of neoaorta from pulmonary artery, Blalock-Taussig shunt for pulmonary perfusion (3 weeks) o Damus-Kaye-Stansel anastomosis: Variation of Norwood with side-to-side anastomosis between PA and hypoplastic ascending aorta o Conversion to hemi-Fontan: Glenn shunt between superior vena cava and right PA (4-6 months) o Fontan: Fenestrated venous conduit through right atrium of inferior caval flow to right PA (1.5-2 years)  Marginally hypoplastic LV: Biventricular repair may be feasible o LV volume is commonly underestimated with echocardiography o Functional MR (SSPE cine: Ventricular volumes and function; PC-MRA: Flow volumes) is more accurate  In some centers: Cardiac transplantation SELECTED REFERENCES 1. Feinstein JA et al: Hypoplastic left heart syndrome: current considerations and expectations. J Am Coll Cardiol. 2012 Jan 3;59(1 Suppl):S1-42. Review. Erratum in: J Am Coll Cardiol. 59(5):544, 2012 2. Boris JR: Primary care cardiology for patients with hypoplastic left heart syndrome. Cardiol Young. 21 Suppl 2:53-8, 2011 3. Dadlani GH et al: Long-term management of patients with hypoplastic left heart syndrome: the diagnostic approach at All Children's Hospital. Cardiol Young. 21 Suppl 2:80-7, 2011 4. Fuller S et al: Neonatal surgical reconstruction and perioperative care for hypoplastic left heart syndrome: current strategies. Cardiol Young. 21 Suppl 2:38-46, 2011 5. Nguyen T et al: Echocardiography of hypoplastic left heart syndrome. Cardiol Young. 21 Suppl 2:28-37, 2011 6. Sundareswaran KS et al: Impaired power output and cardiac index with hypoplastic left heart syndrome: a magnetic resonance imaging study. Ann Thorac Surg. 82(4):1267-75; discussion 1275-7, 2006 7. Muthurangu V et al: Cardiac magnetic resonance imaging after stage I Norwood operation for hypoplastic left heart syndrome. Circulation. 112(21):3256-63, 2005 8. Oye RG et al. Hypoplastic left heart syndrome. In Mavroudis C et al: Pediatric Cardiac Surgery. 3rd ed. Philadelphia: Mosby. 560-74, 2003 9. Bardo DM et al: Hypoplastic left heart syndrome. Radiographics. 21(3):705-17, 2001 10. Cheatham JP: Intervention in the critically ill neonate and infant with hypoplastic left heart syndrome and intact atrial septum. J Interv Cardiol. 14(3):357-66, 2001 11. Herman TE et al: Special imaging casebook. Hypoplastic left heart, prostaglandin therapy gastric focal foveolar hyperplasia and brown-fat necrosis. J Perinatol. 21(4):263-5, 2001 12. Rosenthal A et al: Hypoplastic left heart syndrome. In Moller JH et al: Pediatric Cardiovascular Medicine. 1st ed. Philadelphia: Churchill Livingstone. 594-605, 2000 P.2:55

Image Gallery

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(Left) Axial CTA shows relative hypoplasia of the left ventricle in a patient with hypoplastic left heart syndrome. There is marked dilatation of the right atrium and ventricle . (Right) Axial image in the same patient shows hypoplastic ascending aorta , a large pulmonary artery serving as cardiac output conduit, and a right-sided cavopulmonary shunt (Glen) .

(Left) Oblique sagittal MRA shows a dilated main pulmonary artery serving as the main cardiac outflow channel after Norwood repair for hypoplastic left heart syndrome. (Right) Axial CTA image in a patient status post Norwood procedure for hypoplastic left heart syndrome shows a connection between the left and right atria from atrial septectomy and a small left ventricle . The right atrium and right ventricle are dilated.

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(Left) Oblique VR sagittal image from CTA shows a markedly dilated pulmonary artery , which provides flow to the systemic circulation status post Norwood surgery. (Right) Coronal oblique VR CTA shows a modified BlalockTaussig shunt perfusing the pulmonary arterial circulation in the same patient. In the Norwood surgery, the main pulmonary artery is used to widen the ascending aorta. Flow to the pulmonary arterial circulation must be surgically created.

Heterotaxia Syndromes Heterotaxia Syndromes Suhny Abbara, MD, FSCCT Christopher M. Walker, MD Key Facts Imaging  Abnormal symmetry in chest and abdomen  Not all characteristic imaging findings of asplenia or polysplenia need to be present to diagnose the syndrome  Bilateral left- or right-sidedness in chest  Findings of congenital heart disease  Transverse liver  Cardiac apex and stomach not on same side  Both asplenia and polysplenia syndromes o Cardiac malposition (40%: Meso/dextrocardia) o Transverse liver o Right-sided stomach with levocardia, left-sided stomach with dextrocardia, or midline stomach  Echocardiogram is often definitive test for characterization of intracardiac anomalies, abnormal systemic &/or pulmonary venous connections  Upper GI study is used to exclude malrotation Pathology  2 major subtypes o Asplenia syndrome = bilateral right-sidedness o Polysplenia syndrome = bilateral left-sidedness Clinical Issues  Asplenia: Often male neonate with severe cyanosis, susceptibility for infections  Polysplenia: More variable, often presents later, equal gender distribution  Associated abnormalities o Malrotation, volvulus, preduodenal portal vein, absent gallbladder, extrahepatic biliary atresia, short pancreas  1st-year mortality: 85% asplenia, 65% polysplenia Diagnostic Checklist  Rigorous application of segmental analysis on cross-sectional study will resolve any complex case 153

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(Left) 3D reconstruction of MDCT tracheobronchial tree shows symmetric long mainstem bronchi with late takeoff of the upper lobe bronchi bilaterally, indicating bilateral left-sidedness or left isomerism. (Right) Axial CTA in the same patient shows enlarged azygos vein due to interrupted inferior vena cava and bilateral pulmonary arteries arching over the mainstem bronchi, indicating bilateral hyparterial bronchi. This latter relationship is often best appreciated on coronal views.

(Left) Sagittal HRCT in the same patient shows the right lung with a major fissure and absence of a minor fissure, indicating bilobed right lung. (Right) Sagittal HRCT of the left lung also shows only a major fissure , indicating bilateral bilobed (left) lungs, consistent with left isomerism or polysplenia. P.2:57

TERMINOLOGY Synonyms  Situs ambiguous, right/left isomerism, cardiosplenic syndromes, Ivemark syndrome Definitions  Disturbance of normal left-right asymmetry in position of thoracic and abdominal organs IMAGING General Features  Best diagnostic clue o Abnormal symmetry in chest and abdomen o All imaging findings need not be present Radiographic Findings  Radiography 154

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o

o

Bilateral left- or right-sidedness in chest; findings of congenital heart disease (CHD); transverse liver; cardiac apex and stomach not on same side Asplenia syndrome  Bilateral minor fissures  Symmetrical short mainstem bronchi with right-sided morphology (narrow carinal angle)  Main bronchi are located superior to main pulmonary arteries (eparterial bronchus)  Cardiomegaly, pulmonary edema Polysplenia syndrome  No minor fissure on either side  Symmetrical long mainstem bronchi with left-sided morphology (wide carinal angle)  Main bronchi are located inferior to main pulmonary arteries (hyparterial bronchus)  Prominent azygos shadow on frontal radiograph from interrupted inferior vena cava (IVC) Both syndromes  Cardiac malposition (40%: Meso-/dextrocardia)  Transverse liver  Right-sided stomach with levocardia, left-sided stomach with dextrocardia, or midline stomach

CT Findings  CTA o o o

Rapid examination of chest and abdomen: Situs abnormalities, systemic and pulmonary venous connections, tracheobronchial anatomy Best for postop patients (metallic clips, coils, stents) Can replace and often provide more anatomic information than diagnostic angiocardiography

MR Findings  T1WI o Multiplanar imaging for segmental analysis of intracardiac connections and defects  T2* GRE o Cine MR for ventricular volumes and function to determine suitability for biventricular vs. univentricular (Fontan) repair  MRA o Gadolinium-enhanced 3D MRA: Comparable to CTA o Ultrafast, time-resolved gadolinium-enhanced MRA with repeated acquisitions allows for dynamic circulation study o Phase contrast MRA for flow/shunt quantification Echocardiographic Findings  Echocardiogram o Often definitive test for characterization of intracardiac anomalies, abnormal systemic &/or pulmonary venous connections Other Modality Findings  Upper GI study: Malrotation is frequently associated Imaging Recommendations  Protocol advice o Echocardiography, followed by MR o CTA for anatomic study in postoperative patients DIFFERENTIAL DIAGNOSIS Situs Inversus Totalis (I, L, L)  Mirror image of normal  Low association with CHD (3-5%); may be associated with immotile cilia syndrome (Kartagener): Sinusitis, bronchiectasis, infertility True Dextrocardia, Abdominal Situs Solitus and Levocardia, Abdominal Situs Inversus  Both have high association with CHD (95-100%) Dextroversion of Heart  Heart is positioned in right chest with apex and stomach still directed toward the left  In right pulmonary hypoplasia (scimitar syndrome), left-sided mass lesions (diaphragmatic hernia, cystic adenomatoid malformation of lung) PATHOLOGY General Features  Genetics o No specific genetic defect in majority, presumed multifactorial inheritance 155

Diagnostic Imaging Cardiovascular 

Heterotaxy syndrome represents a spectrum with overlap between classic asplenia and polysplenia manifestations and other anomalies  Embryology o Early embryological disturbance (5th week of gestation), leading to complex anomalies  Pathophysiology o Determined by complexity of associated CHD o Asplenia syndrome with anomalous pulmonary venous connections  Findings of pulmonary venous outflow obstruction may be masked when there is restriction to pulmonary arterial inflow at the same time (pulmonary atresia) Staging, Grading, & Classification  Segmental approach to analysis of complex cardiac anomalies with cardiac malposition  Segmental analysis summarized by 3-letter code: (S, D, D), (I, L, L), (S, D, L) o Visceroatrial situs designated by S (solitus = normal) or I (inversus = mirror image of normal)  Any arrangement other than situs solitus or inversus is termed situs ambiguous (heterotaxia) P.2:58 

Always associated on same side are  Spleen, stomach, descending aorta, anatomic left atrium, bilobed lung, hyparterial bronchus  Major lobe of liver, IVC, anatomic right atrium, trilobed lung, eparterial bronchus o Ventricular loop: D (normal) or L (inverted) o Orientation of great arteries (presence of transposition) also designated by D or L  Connections: Concordant or discordant  Associated abnormalities: Transposition of great arteries (TGA), double outlet right ventricle (DORV), total anomalous pulmonary venous return (TAPVR)  2 major subtypes o Asplenia syndrome = bilateral right-sidedness  Absence of spleen  IVC and aorta on same side  Bilateral superior vena cava (SVC) (36%), absent coronary sinus  Right isomerism of atrial appendages  Common atrium with band-like remnant of septum crossing atria in anteroposterior direction  Bilateral trilobed lungs  Bilateral eparterial bronchi  Associated with severe cyanotic CHD (atrioventricular septal defect, common atrioventricular valve, DORV, TGA, pulmonary stenosis/atresia)  Abnormalities of pulmonary venous connections: TAPVR (> 80%); often obstructed, below diaphragm (type III) o Polysplenia syndrome = bilateral left-sidedness  Multiple spleens, anisosplenia, multilobed spleen  Abnormalities of systemic venous connections: Azygos or hemiazygos continuation of IVC (> 70%), hepatic veins drain separately into common atrium  Bilateral SVC (41%), connect to coronary sinus  Left isomerism of atrial appendages  Common atrium or large ostium primum atrial septal defect (ASD)  Bilateral bilobed lungs  Bilateral hyparterial bronchi  Associated with less severe CHD and specifically left to right shunts (ASD, partial anomalous pulmonary venous return, and atrioventricular canal) CLINICAL ISSUES Presentation  Most common signs/symptoms o Asplenia: Male neonate with severe cyanosis, susceptibility for infections o Polysplenia: More variable, often presents later  Other signs/symptoms

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Malrotation, volvulus, preduodenal portal vein, absent gallbladder, extrahepatic biliary atresia, short pancreas

Demographics  Epidemiology o Prevalence 1 per 22,000 to 24,000; 1-3% of CHD o Asplenia is more common in boys; equal sex ratio for polysplenia Natural History & Prognosis  1st-year mortality: 85% asplenia, 65% polysplenia Treatment  Supportive, prostaglandins, antibiotic prophylaxis  Asplenia/polysplenia with pulmonary overcirculation: Pulmonary artery banding  Asplenia with obstructed pulmonary flow and TAPVR: Delicate balance between pulmonary arterial inflow and venous outflow o Placement of palliative systemic to pulmonary artery (Blalock-Taussig or central) shunt increases inflow o TAPVR repair needs to be done at the same time to reduce outflow obstruction  Early biventricular repair, if possible  Univentricular repair, initial step is Glenn or hemi-Fontan  Completion of modified Fontan operation if possible o 1 or more hepatic veins may have to be excluded from Fontan shunt → venovenous collaterals o CTA or MRA prior to catheterization as road map for coil embolization of collaterals  Polysplenia: Incorporation of azygos vein to cavopulmonary anastomosis (Kawashima operation) o Postoperative: Development of pulmonary to systemic venous collaterals, arteriovenous malformations, pulmonary vein stenosis DIAGNOSTIC CHECKLIST Image Interpretation Pearls  Rigorous application of segmental analysis on cross-sectional study will resolve any complex case SELECTED REFERENCES 1. Kim SJ: Heterotaxy syndrome. Korean Circ J. 41(5):227-32, 2011 2. Maier M et al: Annular pancreas and agenesis of the dorsal pancreas in a patient with polysplenia syndrome. AJR Am J Roentgenol. 188(2):W150-3, 2007 3. Maldjian PD et al: Approach to dextrocardia in adults: review. AJR Am J Roentgenol. 188(6 Suppl):S39-49; quiz S358, 2007 4. Fulcher AS et al: Abdominal manifestations of situs anomalies in adults. Radiographics. 22(6):1439-56, 2002 5. Hong YK et al: Efficacy of MRI in complicated congenital heart disease with visceral heterotaxy syndrome. J Comput Assist Tomogr. 24(5):671-82, 2000 6. Applegate KE et al: Situs revisited: imaging of the heterotaxy syndrome. Radiographics. 19(4):837-52; discussion 853-4, 1999 7. Gayer G et al: Polysplenia syndrome detected in adulthood: report of eight cases and review of the literature. Abdom Imaging. 24(2):178-84, 1999 8. Chen SJ et al: Usefulness of electron beam computed tomography in children with heterotaxy syndrome. Am J Cardiol. 81(2):188-94, 1998 9. Oleszczuk-Raschke K et al: Abdominal sonography in the evaluation of heterotaxy in children. Pediatr Radiol. 25 Suppl 1:S150-6, 1995 10. Winer-Muram HT: Adult presentation of heterotaxic syndromes and related complexes. J Thorac Imaging. 10(1):43-57, 1995 11. Geva T et al: Role of spin echo and cine magnetic resonance imaging in presurgical planning of heterotaxy syndrome. Comparison with echocardiography and catheterization. Circulation. 90(1):348-56, 1994 12. Winer-Muram HT et al: The spectrum of heterotaxic syndromes. Radiol Clin North Am. 27(6):1147-70, 1989 P.2:59

Image Gallery

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Diagnostic Imaging Cardiovascular

(Left) Axial CTA shows a univentricular heart (single ventricle) with a common atrium and a common atrioventricular valve . Note a remnant of the atrial septum . Note pectus deformity and median sternotomy wires. (Right) Axial CTA through the abdomen in the same patient shows absence of the spleen, consistent with asplenia.

(Left) Coronal MPR of the same CTA shows abnormally symmetric short mainstem bronchi with early takeoff of upper lobe bronchi bilaterally. Note that neither bronchus has a pulmonary artery arching over it (bilateral eparterial bronchi), indicating right isomerism/asplenia. (Right) Coronal CT MPR shows the normal asymmetry with a short right and a long left mainstem bronchi (upper lobe bronchi ). The left PA arches over the (hyparterial) bronchus; the right does not (eparterial bronchus).

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(Left) Coronal CTA shows symmetric long bilateral hyparterial bronchi with bilateral pulmonary arteries arching over their respective bronchi , indicating bilateral left-sidedness. Note the enlarged azygos arch due to azygos continuation of inferior vena cava. Also note the aorta , giving a bilateral double barrel appearance. (Right) Axial CT in the same patient shows multiple spleens, consistent with left isomerism and polysplenia . P.2:60

(Left) Frontal radiograph shows dextrocardia , a right aortic arch , and a bridging or midline liver . The left hemidiaphragm is elevated due to phrenic nerve injury at the time of surgery for tricuspid and pulmonic valve atresia in this patient with heterotaxy and asplenia. (Right) Coronal CECT in the same patient shows dextrocardia ,a bridging liver , and asplenia. Note the Fontan shunt directed from the inferior vena cava to the main pulmonary artery.

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(Left) Axial MR shows dextrocardia , azygos continuation of an interrupted inferior vena cava, and an atrial septal defect . The most common cardiac malformations in polysplenic patients include atrial septal defect, partial anomalous pulmonary venous return, and atrioventricular canal. (Right) Axial MR in the same patient shows polysplenia , bridging liver, and azygos continuation of an interrupted inferior vena cava.

(Left) Axial MR shows hemiazygos continuation of an interrupted inferior vena cava and polysplenia . The liver, stomach, and cardiac apex were in their expected positions. (Right) Axial CECT in the same patient shows a normal-sided stomach and liver. There is an enlarged hemiazygos vein and polysplenia . Cardiac anomalies are usually less severe and present later in polysplenic patients compared to those with asplenia. P.2:61

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Diagnostic Imaging Cardiovascular

(Left) Frontal radiograph shows normal cardiac situs, a right stomach , and a left-sided liver in this infant with asplenia. (Right) Coronal CECT shows bilateral hyparterial bronchi under the right and left pulmonary arteries. Note the enlarged azygos vein from collateral flow due to an interrupted inferior vena cava. Axial CT (not shown) more inferiorly demonstrated polysplenia and a horizontal liver.

(Left) Frontal radiograph shows an enlarged azygos vein from inferior vena cava interruption. The cardiac situs is normal but the gastric bubble is right sided. There is a horizontal liver . (Right) Axial MR in the same patient shows a horizontal liver, polysplenia , a right stomach , and absence of an intrahepatic inferior vena cava.

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Diagnostic Imaging Cardiovascular

(Left) Four-chamber view cine MR in the same patient shows an enlarged right atrium and right ventricle due to a fenestrated atrial septal defect. The Qp:Qs ratio was calculated at 1.6 (normal is 1). Left-to-right shunts are the most common cardiac anomalies associated with polysplenia. (Right) Axial CECT shows an enlarged azygos vein due to an interrupted inferior vena cava. Lower images showed polysplenia.

Ebstein Anomaly Ebstein Anomaly Suhny Abbara, MD, FSCCT Key Facts Imaging  Classic plain film appearance: Massive right-sided cardiomegaly (box-shaped heart)  Small vascular pedicle  Apical displacement of septal tricuspid leaflet (≥ 8 mm/m2 body surface area) o Hemodynamics: Severe tricuspid valve regurgitation o Volume overload to right heart  Right-to-left shunting through patent foramen ovale leads to cyanosis Top Differential Diagnoses  Uhl anomaly and arrhythmogenic right ventricular dysplasia (ARVD) o Similar but distinct entities: Congenital absence (Uhl) or fibrofatty infiltration (ARVD) of right ventricular myocardium  Large atrial septal defect Pathology  Downward displacement of septal and posterior leaflets of tricuspid valve o Although annulus remains in normal position, proximal portions of leaflets are attached to ventricular walls displacing leaflet hingepoints toward apex  3 compartments: Right atrium, atrialized noncontracting inlet portion, and functional outlet portion of right ventricle Clinical Issues  Wide spectrum of findings and ages at 1st presentation; some patients are asymptomatic  Presence of cyanosis depends on balance between right and left atrial pressure  Accessory atrioventricular conduction pathways (pre excitation) → tachyarrhythmias, which can be unexpected and fatal

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(Left) PA radiograph shows markedly enlarged box-shaped heart. Note narrow vascular pedicle and normal to decreased pulmonary vasculature. Pacemaker lead positions demarcate massive right atrial (RA) and ventricular (RV) enlargement. (Right) Lateral radiograph shows enlarged right heart filling retrosternal space. Large distance between pacer leads in SVC and lead tip at anterior RA wall shows degree of RA enlargement. Displaced small left ventricle is posterior to RV lead tip.

(Left) Axial CTA demonstrates congested liver with markedly enlarged inferior vena cava (IVC) and hepatic veins due to tricuspid regurgitation. (Right) Axial CTA in the same patient with Ebstein anomaly shows massively dilated RA , atrialized portion of the RV , and posteriorly displaced small appearing but normal-sized left ventricle . P.2:63

TERMINOLOGY Definitions  Downward displacement of the septal and posterior leaflets of the tricuspid valve o Although annulus remains in normal position, proximal portions of leaflets are attached to ventricular walls, effectively displacing the leaflet hingepoints towards the apex  Classic plain film appearance: Massive right-sided cardiomegaly (box-shaped heart)  Category: Cyanotic, (severe) cardiomegaly, normal or decreased pulmonary vascularity  Hemodynamics: Severe tricuspid valve regurgitation o Volume overload to right heart o Right-to-left shunting through patent foramen ovale (PFO) leads to cyanosis IMAGING General Features 163

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Best diagnostic clue o Apical displacement of septal tricuspid leaflet (≥ 8 mm/m 2 body surface area)  Location o Tricuspid valve Radiographic Findings  Radiography o Severe right-sided cardiomegaly  Heart size can be near normal in the newborn period but can also be massively enlarged at birth  Heart increases gradually in size over time, reaching massive proportions in untreated cases during adulthood  Cardiothoracic ratio used as follow-up parameter o Small vascular pedicle o May mimic large pericardial effusion CT Findings  CTA o Right-chamber enlargement with “atrialized” portion of right ventricle o Normal-sized left atrium and ventricle; latter often displaced into posterior left chest o May demonstrate apical displacement of septal tricuspid valve leaflet and sail-like anterior leaflet  Electron beam or MDCT cine CT has been used for functional analysis of ventricular contraction o Signs of right ventricular (RV) volume overload on cine imaging: Ventricular septal straightening during diastole only MR Findings  T1WI o Right chamber best seen on long-axis imaging  T2* GRE o Cardiac-gated, steady-state free precession cine MR  Ventricular volumes, ejection fraction of each ventricle, tricuspid regurgitation fraction  Left ventricular function affected by RV dilatation, bowing of septum, mitral valve prolapse  MRA o Associated cardiac abnormalities  Phase contrast o Flow/shunt calculations o Degree of tricuspid regurgitation (regurgitant volume) Echocardiographic Findings  Echocardiogram o Right-chamber enlargement, “atrialized” portion of right ventricle o Enlarged tricuspid annulus (expressed in z-score) o Apical displacement of septal tricuspid leaflet (> 15 mm in children < 14 years; > 20 mm in adults, or 2 ≥ 8 mm/m body surface area)  Color Doppler o Tricuspid regurgitation o PFO with right-to-left shunting Angiographic Findings  Conventional o Characteristic notch at inferior RV border at insertion of displaced anterior tricuspid leaflet o Seldom required for primary diagnosis Nuclear Medicine Findings  Radionuclide imaging o Decreased left ventricular ejection fraction in 50% Imaging Recommendations  Protocol advice o Anatomic and functional assessment with echocardiography in infants o Cine MR in (young) adults DIFFERENTIAL DIAGNOSIS Large Atrial Septal Defect  Acyanotic  Increased pulmonary vascularity 164

Diagnostic Imaging Cardiovascular  Left-to-right flow through atrial septal defect Pericardial Effusion  Acyanotic  Easy differentiation with echocardiography Tricuspid Regurgitation  Primary: Due to dysplastic valve  Secondary: Due to pulmonary atresia with intact ventricular septum Uhl Anomaly and Arrhythmogenic Right Ventricular Dysplasia (ARVD)  Similar but distinct entities with congenital absence (Uhl) or fibrofatty infiltration (ARVD) of RV myocardium  May be differentiated from Ebstein anomaly with spin-echo and cine MR Right-Sided Obstructive Cyanotic Heart Lesions With Decreased Pulmonary Vascularity  Tetralogy of Fallot  Pulmonary atresia o With ventricular septal defect and aortopulmonary collaterals o With intact ventricular septum  Ebstein anomaly and pulmonary atresia with intact ventricular septum are the 2 lesions that cause the most severe cardiomegaly  Tricuspid atresia P.2:64  Transposition of the great arteries (TGA) with pulmonary stenosis  Double outlet RV with pulmonary stenosis PATHOLOGY General Features  Genetics o Most often sporadic  Associated abnormalities o PFO, secundum atrial septal defect in 90%  Massive right-sided chamber enlargement  3 compartments: Right atrium, atrialized noncontracting inlet portion, and functional outlet portion of RV  Ebstein anomaly frequently involves left-sided tricuspid valve in congenitally corrected (L) transposition of great arteries  Embryology o Insufficient separation of tricuspid valve leaflets and chordae tendineae from right ventricular endocardium  Pathophysiology o Massive tricuspid regurgitation o Volume overload to right side of heart o Right-to-left shunt through PFO → cyanosis o Left ventricular diastolic dysfunction may result from massive right-sided cardiac enlargement o Arrhythmias due to conduction abnormalities Gross Pathologic & Surgical Features  Thickened valve leaflets, adherent to underlying myocardium  Downward displacement of septal and posterior tricuspid leaflets  Normally placed, redundant, “sail-like” anterior tricuspid leaflet  May occur on left side of heart with congenitally corrected (L) transposition CLINICAL ISSUES Presentation  Most common signs/symptoms o Wide spectrum of findings and ages at 1st presentation; some patients are asymptomatic o Chronic right heart failure  Decreased exercise tolerance (classified as New York Heart Association classes I-IV) o Presence of cyanosis depends on balance between right and left atrial pressure  Physiological drop in pulmonary vascular resistance in neonatal period → decrease in rightto-left shunting through PFO → gradual improvement in cyanosis in first weeks of life  Polycythemia  Other signs/symptoms 165

Diagnostic Imaging Cardiovascular o o o o

Hydrops fetalis in neonatal cases Severe cardiomegaly in fetal life → pulmonary hypoplasia Thrombosis, paradoxical embolus Arrhythmias  Atrial fibrillation, atrial flutter  Accessory atrioventricular conduction pathways (pre excitation) → tachyarrhythmias, which can be unexpected and fatal

Demographics  Age o 1st presentation can range from newborn period through old age (average: 14 years)  Epidemiology o < 1% of congenital cardiac anomalies; incidence 1/210,000 live births o M:F = 1:1 Natural History & Prognosis  Sudden death due to fatal atrial arrhythmias  Uncomplicated pregnancies possible in women with hemodynamically well-balanced lesions  Prognosis is dependent on hemodynamic significance of tricuspid regurgitation, presence of cyanosis Treatment  Supportive treatment in cyanotic neonate: Oxygen, nitric oxide ventilation to lower pulmonary resistance  Systemic to pulmonary (Blalock-Taussig and central) shunts are ineffective  Some patients benefit from total right-sided heart bypass procedures (Glenn → Fontan surgical treatment pathway)  Tricuspid valve replacement &/or reconstruction (valvuloplasty) is definitive repair procedure o Valvuloplasty and bioprosthesis placement are preferable to mechanical valve (allow growth; no need for lifelong anticoagulation) o Valvuloplasty uses tissues from existing valve (redundant anterior tricuspid leaflet) o Bioprosthesis: Homograft or xenograft (porcine valve)  Indications for valve repair o NYHA classes III and IV o NYHA classes I and II with cardiothoracic ratio > 0.65 o Significant cyanosis (arterial saturation < 80%) &/or polycythemia (Hb > 16 g/dL) o History of paradoxical embolus o Arrhythmia due to accessory atrioventricular pathway  Arrhythmia treatments o Radiofrequency ablation o Antiarrhythmic drugs o Permanent pacemaker implantation SELECTED REFERENCES 1. Tobler D et al: Right heart characteristics and exercise parameters in adults with Ebstein anomaly: new perspectives from cardiac magnetic resonance imaging studies. Int J Cardiol. 165(1):146-50, 2013 2. Attenhofer Jost CH et al: Prospective comparison of echocardiography versus cardiac magnetic resonance imaging in patients with Ebstein's anomaly. Int J Cardiovasc Imaging. 28(5):1147-59, 2012 3. Beerepoot JP et al: Case 71: Ebstein anomaly. Radiology. 231(3):747-51, 2004 4. Chauvaud S et al: Ebstein's anomaly: repair based on functional analysis. Eur J Cardiothorac Surg. 23(4):525-31, 2003 5. Dearani JA et al: Ebstein's anomaly of the tricuspid valve. In Mavroudis C et al: Pediatric Cardiac Surgery. 3rd ed. Philadelphia: Mosby. 524-36, 2003 P.2:65

Image Gallery

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(Left) PA radiograph shows mildly enlarged cardiac contour with normal pulmonary vascularity. The right heart border is particularly prominent, suggesting right atrial enlargement. (Right) Lateral radiograph shows increased opacity in the retrosternal clear space , indicating right ventricular enlargement. This patient has a mild form of Ebstein anomaly.

(Left) Coronal oblique SSFP MR in the same patient demonstrates enlarged right atrium and ventricle. The inferior portion of the left heart border seen on the radiograph actually represents enlarged left ventricle . Note also flattening of ventricular septum . (Right) Coronal oblique SSFP MR shows enlarged right ventricle and its outflow tract pasted against sternum , causing the retrosternal clear space opacity on above radiograph. The normal-sized left ventricle is displaced posteriorly.

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(Left) Axial GRE MR shows right atrial dilatation and regurgitant dephasing jet arising from coaptation site of mildly apically displaced septal leaflet with remaining leaflets of tricuspid valve. This mild Ebstein variant was an incidental finding. (Right) Axial NECT in Ebstein patient illustrates that chamber enlargement can be identified without contrast. Posteriorly displaced interventricular groove and right atriventricular groove indicate moderate right ventricular enlargement. P.2:66

(Left) Axial CTA in a patient with Ebstein anomaly shows a markedly enlarged superior vena cava and right atrial appendage , secondary to longstanding tricuspid insufficiency. Note the normal-sized pulmonary trunk and arteries. (Right) Axial CTA in the same patient demonstrates markedly enlarged and leftward displaced right ventricular outflow tract despite normal-sized pulmonary arteries. The left atrium is unremarkable, but there is a giant right atrium .

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(Left) Axial CTA shows apically displaced septal leaflet of tricuspid valve dividing the ventricle into the atrialized portion and functional ventricular portion . Note small posteriorly displaced left atrium and ventricle, and giant right atrium. (Right) 3D volume-rendered reconstruction image of the same patient demonstrates the giant right atrium (RA) and ventricle (RV). Note the relatively small appearance of the normal aortic arch (Ao = aorta).

(Left) Short-axis SSFP in systole shows ventricular septum normally bowed toward the right ventricle. Note the sail-like anterior tricuspid valve leaflet . (Right) Short-axis SSFP in diastole in the same patient shows the ventricular septum now straightened, indicating right ventricular volume overload. P.2:67

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Diagnostic Imaging Cardiovascular

(Left) Axial NECT in patient with Ebstein anomaly shows markedly enlarged right atrium and ventricle. Despite absence of contrast, the RV can be identified by the triangular atrioventricular groove fat and the anterior interventricular groove fat . The left ventricle is normal-sized and posteriorly displaced. (Right) Axial NECT in the same patient shows markedly enlarged hepatic veins and inferior vena cava due to chronic congestions secondary to severe tricuspid regurgitation.

(Left) PA radiograph shows enlarged box-shaped cardiac silhouette . Pulmonary vasculature is decreased and vascular pedicle is narrow. (Right) Four-chamber SSFP image during diastole shows massive enlargement of right atrium and normal-sized displaced left atrium and left ventricle with flattened ventricular septum. Displaced septal tricuspid leaflet divides RV into atrialized portion of the RV and RV proper . Note fenestrated atrial septal defect causing dephasing .

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(Left) Short-axis SSFP MR image during systole shows markedly enlarged right ventricle and a regurgitant jet across the tricuspid valve due to the septal displacement and lack of coaptation of the leaflets. (Right) Short-axis MR SSFP image in diastole shows enlarged right ventricle and normal-sized displaced left ventricle with diastolic flattening of the ventricular septum causing classic D-shaped appearance of the left ventricle, which is indicative of right heart volume overload.

Cor Triatriatum Cor Triatriatum Suhny Abbara, MD, FSCCT Cameron Hassani, MD Key Facts Terminology  Usually refers to cor triatriatum sinister  Cor triatriatum sinister: Congenital anomaly with fibromuscular diaphragm or membrane dividing left atrium into posterior and anterior chambers o Posterior (proximal) chamber receives pulmonary veins o Anterior (distal) chamber gives rise to left atrial appendage and mitral valve o Communication between chambers through defect of varying size  Cor triatriatum dexter: Analogous abnormality in right atrium Imaging  Arterial-phase CT demonstrates membrane of varying size dividing left atrium into posterior and anterior chambers o Cor triatriatum sinister: Membrane attaches between left atrial appendage and pulmonary vein ostia o Distinguished from supravalvular ring by being superior/posterior to left atrial appendage o Paraseptal long-axis reconstructions helpful in visualizing insertion site with respect to left atrial appendage ostium Top Differential Diagnoses  Submitral ring or web o Web connects between left atrial appendage and mitral annulus  Total anomalous pulmonary venous return o Common posterior collecting vein receives pulmonary veins and does not connect to left atrium o Supracardiac, infracardiac, or cardiac right-sided drainage site may be identified

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(Left) Axial oblique cardiac CT shows a thin membrane dividing the left atrium into an anterior and posterior component. The posterior portion of the left atrium receives the pulmonary veins , and the anterior chamber connects to the left atrial appendage . (Right) Vertical long-axis (2-chamber) cardiac CT in the same patient shows the pulmonary vein draining into the posterior chamber . The membrane inserts between the pulmonary vein ostia and left atrial appendage ostium .

(Left) Vertical long-axis (2-chamber) MR cine demonstrates a thin membrane within the left atrium dividing it into an anterior and posterior chambers. Note the incomplete nature of the membrane allowing communication between the chambers. Also note the left atrial enlargement. (Right) Horizontal long-axis (4-chamber) MR cine in a patient with cor triatriatum dexter. Thin membrane divides the right atrium into 2 chambers. P.2:69

TERMINOLOGY Synonyms  Usually refers to cor triatriatum sinister  Cor triatriatum dexter is an analogous abnormality in right atrium Definitions  Cor triatriatum sinister: Fibromuscular diaphragm or membrane dividing left atrium into 2 chambers o Posterior (proximal) chamber receives pulmonary veins o Anterior (distal) chamber gives rise to left atrial appendage (LAA) and mitral valve o Communication between chambers through defect of varying size in membrane  Cor triatriatum dexter: Analogous abnormality in right atrium; due to persistence of right valve of sinus venosus 172

Diagnostic Imaging Cardiovascular o

2 right atrial chambers  Sinus venarum receiving superior vena cava (SVC) and inferior vena cava (IVC)  Trabeculated portion connecting to tricuspid valve May mimic Ebstein anomaly

o IMAGING General Features  Best diagnostic clue o Membrane of varying size dividing left atrium into posterior and anterior chambers  Location o Cor triatriatum sinister: Membrane attaches between LAA and pulmonary vein ostia CT Findings  CECT o Best seen on arterial-phase gated CT  Paraseptal long-axis reconstructions helpful in visualizing insertion site with respect to LAA ostium o Signs of pulmonary venous obstruction due to gradient across membrane (mimics mitral stenosis)  Left atrium and right chambers may be dilated  Pulmonary venous hypertension (PVH) and interstitial edema  May develop main pulmonary artery dilation secondary to chronic PVH MR Findings  Findings on black blood or cine images similar to CT  Cine imaging or phase-contrast images may demonstrate jet across membrane Echocardiographic Findings  Echocardiogram o Transesophageal echocardiography is preferred for membrane visualization o May show high-velocity Doppler flow in distal atrial chamber and at mitral orifice o Diastolic fluttering of mitral valve leaflets o Distinguished from supravalvular ring by being superior/posterior to left atrial appendage Imaging Recommendations  Protocol advice o Include left ventricular long axis planes to include membrane attachment site, mitral valve, and LAA ostium DIFFERENTIAL DIAGNOSIS Submitral Ring or Web  Web connects between left atrial appendage and mitral annulus Total Anomalous Pulmonary Venous Return  Common posterior collecting vein receives pulmonary veins and does not connect to left atrium  Supracardiac, infracardiac, or cardiac right-sided drainage site may be identified Cor Triatriatum Dexter  Membrane dividing right atrium into anterior and posterior (receiving IVC and SVC) chambers PATHOLOGY General Features  Etiology o Congenital malformation due to failure of incorporation of common pulmonary vein into left atrium Staging, Grading, & Classification  Loeffler classification o Group 1: No opening o Group 2: 1 or more small openings o Group 3: Single large opening CLINICAL ISSUES Presentation  Most common signs/symptoms o Dyspnea, palpitations, and orthopnea as a result of obstruction by intraatrial membrane  Symptom severity depends on fenestration size  Larger defects cause no or only mild symptoms o Pulmonary hypertension and right-sided heart failure  Symptoms may mimic mitral valve stenosis  May present with pulmonary venous hypertension 173

Diagnostic Imaging Cardiovascular Treatment  Surgical resection or percutaneous catheter disruption for symptomatic patients SELECTED REFERENCES 1. Barrea C et al: Images in cardiovascular medicine: Cor triatriatum dexter mimicking Ebstein disease. Circulation. 120(11):e86-8, 2009 2. Modi KA et al: Diagnosis and surgical correction of cor triatriatum in an adult: combined use of transesophageal and contrast echocardiography, and a review of literature. Echocardiography. 23(6):506-9, 2006 3. Sarikouch S et al: Adult congenital heart disease: cor triatriatum dextrum. J Thorac Cardiovasc Surg. 132(1):164-5, 2006 4. Slight RD et al: Cor-triatriatum sinister presenting in the adult as mitral stenosis: an analysis of factors which may be relevant in late presentation. Heart Lung Circ. 14(1):8-12, 2005

Tetralogy of Fallot Tetralogy of Fallot Suhny Abbara, MD, FSCCT Christopher M. Walker, MD Key Facts Terminology  Tetralogy of Fallot (TOF, TET)  Underdevelopment of pulmonary infundibulum due to unequal partitioning of conal truncus resulting in subvalvular or valvular right ventricular (RV) outflow tract (RVOT) stenosis, subaortic ventricular septal defect (VSD), overriding aorta, and RV hypertrophy Imaging  Infundibular stenosis of RVOT  Classic radiographic appearance: Boot-shaped heart  Right-sided aortic arch in 25% of cases  Decreased-to-normal pulmonary vascularity (pulmonary oligemia)  Usually no cardiac enlargement Top Differential Diagnoses  Pulmonary atresia with VSD  Tricuspid atresia with VSD  Trilogy of Fallot  Pentalogy of Fallot Pathology  Classic “blue” TET = decreased pulmonary blood flow → greater right-to-left shunting → cyanosis  “Pink” TET = normal or increased pulmonary flow → congestive heart failure  Frequent associations o Absence of pulmonary valve: Severe pulmonary regurgitation → aneurysmal dilatation of pulmonary arteries → tracheobronchial compression o Coronary anomalies: Left anterior descending artery arising from right coronary artery and crossing RVOT, with implications for surgical repair o Down syndrome (trisomy 21) Clinical Issues  Most common cyanotic heart lesion

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(Left) Graphic shows subvalvular and valvular pulmonary stenosis with hypoplastic pulmonary artery, membranous VSD, muscular right ventricular (RV) hypertrophy, and overriding aorta receiving mixed blood from RV and left ventricle (LV), indicating TOF. (Right) Frontal radiograph in a 9-year-old boy with repaired tetralogy of Fallot shows RV hypertrophy indicated by uplifting of the cardiac apex . The pulmonary vascularity shows normal status post repair, and the aortic arch is left sided.

(Left) LVOT SSFP MR shows the typical features of TOF with a highly membranous VSD , aorta (Ao) overriding the interventricular septum, and RV hypertrophy . (Right) Axial SSFP MR shows RV hypertrophy and a membranous VSD . MR is ideally suited to identify the anatomy of the pulmonary arteries and depict other sources of pulmonary arterial blood flow (e.g., aortopulmonary arterial collaterals or PDA) prior to definitive operative repair. P.2:71

TERMINOLOGY Abbreviations  Tetralogy of Fallot (TOF, TET) Definitions  Underdevelopment of pulmonary infundibulum due to unequal partitioning of conal truncus resulting in subvalvular or valvular right ventricular (RV) outflow tract (RVOT) stenosis, subaortic ventricular septal defect (VSD), overriding aorta, and RV hypertrophy IMAGING General Features  Best diagnostic clue o Infundibular stenosis of RVOT Radiographic Findings 175

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Radiography o Classic radiographic appearance: Boot-shaped heart (a.k.a. coeur en sabot) o Normal heart size o Right-sided aortic arch in 25% of cases o RV hypertrophy and concave pulmonary artery segment o Decreased pulmonary vascularity (pulmonary oligemia) o Normal pulmonary vascularity CT Findings  CTA o May demonstrate aortopulmonary systemic collateral arteries o CTA with volume rendition: Depicts pulmonary artery (PA) anatomy o Non-gated CTA: Can usually show RV hypertrophy o Gated CTA: Excellent tool for depicting prior surgical repairs ± potential complications in adults  Blalock-Taussig (BT) shunt: Subclavian artery anastomosed to pulmonary artery or tube graft (modified BT); usually ligated at time of definitive repair  Pott shunt: Left pulmonary artery to descending aorta; no longer performed  Waterston-Cooley shunt: Ascending aorta to right pulmonary artery  Definitive repair: Infundibular patch or tube graft repair + VSD closure MR Findings  Cardiac gated T1WI (axial views) o Preoperative definition of PA anatomy, PA stenosis o Postoperative definition of PA anatomy, patency of BT shunts  Steady-state free precession (SSFP) cine in short axis o RV function, ejection fraction  Phase-contrast MR o RV function, regurgitation fraction, fractional PA flow  3D gadolinium MRA o Depiction of PA anatomy and major aortopulmonary collateral arteries (MAPCAs) Ultrasonographic Findings  Grayscale ultrasound o In utero: Dilated aorta overriding interventricular septum o No RV hypertrophy in 2nd trimester o Perimembranous VSD and RVOT narrowing may be apparent Echocardiographic Findings  Echocardiogram o VSD location, additional muscular VSDs o Degree of aortic override, position of arch o Degree of RVOT obstruction, function of pulmonary valve o Anatomy of branch PAs Angiographic Findings  Conventional  Cardiac catheterization and angiography findings o Coronary anatomy o PA branch stenosis: Balloon angioplasty with stent placement o Anatomy/distribution of MAPCAs Imaging Recommendations  Initial diagnosis with echocardiography (pre- or postnatal)  CTA or MR for PA anatomy  Cardiac catheterization for percutaneous interventions  MR in older child with poor acoustic window for functional assessment of postoperative pulmonary regurgitation and RV dysfunction DIFFERENTIAL DIAGNOSIS Pulmonary Atresia With VSD  Considered a subset of TOF o Type A: Only native PAs o Type B: Pulmonary blood flow via both native PAs and MAPCAs o Type C: Only MAPCAs, no native PAs Tricuspid Atresia With VSD 176

Diagnostic Imaging Cardiovascular  Muscular or membranous partition between right atrium and RV  Obligatory shunting from right atrium → left atrium → LV → RV  Decreased pulmonary flow → severe cyanosis at birth  When associated with transposition of great arteries, there is increased pulmonary blood flow Trilogy of Fallot  Pulmonary valvular stenosis, RV hypertrophy, and atrial septal defect (ASD) with right-to-left shunt due to increased right-sided pressures Pentalogy of Fallot  Tetralogy with additional ASD PATHOLOGY General Features  Genetics o Associated with chromosomal abnormalities in 11% (chromosome 22) o Associated with other congenital anomalies in 16%; syndromic in 8% P.2:72  

TOF is most common heart lesion that is associated with right aortic arch Frequent associations o PA branch stenosis or hypoplasia o Absence of pulmonary valve: Severe pulmonary regurgitation → aneurysmal dilatation of PAs → tracheobronchial compression o Patent foramen ovale o Right-sided aortic arch with mirror-image branching (25%) o Coronary anomalies: Left anterior descending artery arising from right coronary artery and crossing RVOT, with implications for surgical repair o Tracheoesophageal fistula o Down syndrome (trisomy 21) o Scoliosis, forked ribs  Embryology o Abnormal bulbotruncal rotation and septation o Primary hypoplasia of infundibular septum  Hemodynamics: RVOT obstruction → pressure overload  Balance between RVOT obstruction and VSD o Classic “blue” TET = decreased pulmonary blood flow → greater right-to left-shunting → cyanosis o “Pink” TET = normal or increased pulmonary flow → congestive heart failure Staging, Grading, & Classification  Category: Cyanotic, normal heart size, decreased pulmonary vascularity CLINICAL ISSUES Presentation  Varying degrees of cyanosis at birth  Hypercyanotic spells with dyspnea on exertion relieved by typical squatting position when fatigued o Squatting pinches the femoral arteries, resulting in increased systemic resistance, which increases pulmonary flow  Clubbing of fingers and toes  Congestive heart failure (large VSD)  After repair: Decreased exercise tolerance, RV dysfunction, arrhythmias (sudden death)  Bacterial endocarditis, stroke due to paradoxical embolus to brain, hyperviscosity syndrome due to polycythemia Demographics  Epidemiology o Incidence: 3-5 per 10,000 live births o Fourth most common congenital heart anomaly o Most common cyanotic heart lesion Natural History & Prognosis  10% of untreated patients live > 20 years  Short-term: Excellent results after early complete repair  Long-term: Determined by RV diastolic dysfunction, pulmonary regurgitation 177

Diagnostic Imaging Cardiovascular Treatment  Palliative shunt o Classic BT shunt: End-to-side subclavian artery to PA (opposite from aortic arch) o Modified BT shunt: Interposition of Gore-Tex graft o Central shunt: Ductus-like connection between aorta and PA  Complete repair: Enlargement of RVOT, closure of VSD o Transannular patch increases RVOT size: Postoperative pulmonary regurgitation o Transatrial-transpulmonary surgical approach favored to spare RV incision  TOF with pulmonary atresia: Usually requires multiple surgeries as patient ages o Restore antegrade flow from RV to PA often with homograft o Diminish collateral supply to PAs  Percutaneous coil embolization  Unifocalization procedure (i.e., detach collaterals from aorta and implant on reconstructed PAs) o Close cardiac shunts DIAGNOSTIC CHECKLIST Consider  MRA if MAPCAs are suspected in children  CTA to detect treatment complications in adults  MR for RV size and pulmonary regurgitation fraction in adults Reporting Tips  Goals of preoperative imaging o Identify pulmonary vascular anatomy  Pulmonary valve or artery stenosis  Pulmonary valve or artery atresia o Locate alternative sources of pulmonary blood flow  Aortopulmonary collaterals  Patent ductus arteriosus  Goals of postoperative imaging o Assess for postoperative complications  Pulmonic valve regurgitation  RV volume and contractility  RVOT aneurysm  Branch PA stenosis  Scar and fibrosis with delayed-contrast imaging SELECTED REFERENCES 1. Kasar PA et al: Computed tomographic angiography in tetralogy of Fallot. Asian Cardiovasc Thorac Ann. 19(5):32432, 2011 2. Frank L et al: Cardiovascular MR imaging of conotruncal anomalies. Radiographics. 30(4):1069-94, 2010 3. Apitz C et al: Tetralogy of Fallot. Lancet. 374(9699):1462-71, 2009 4. Geva T et al: Magnetic resonance imaging-guided catheter interventions in congenital heart disease. Circulation. 113(8):1051-2, 2006 5. Geva T: Indications and timing of pulmonary valve replacement after tetralogy of Fallot repair. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. :11-22, 2006 6. Prasad SK et al: Role of magnetic resonance angiography in the diagnosis of major aortopulmonary collateral arteries and partial anomalous pulmonary venous drainage. Circulation. 109(2):207-14, 2004 7. Haramati LB et al: MR imaging and CT of vascular anomalies and connections in patients with congenital heart disease: significance in surgical planning. Radiographics. 22(2):337-47; discussion 348-9, 2002 8. Holmqvist C et al: Pre-operative evaluation with MR in tetralogy of fallot and pulmonary atresia with ventricular septal defect. Acta Radiol. 42(1):63-9, 2001 P.2:73

Image Gallery

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(Left) Frontal radiograph in a 51-year-old woman with unrepaired tetralogy of Fallot shows massive enlargement of the right and left pulmonary arteries. (Right) Lateral radiograph in the same patient shows enlargement of the right and left main pulmonary arteries. The pulmonary artery enlargement was secondary to longstanding and massive aortopulmonary artery collaterals.

(Left) Sagittal CTA in the same patient shows large aortopulmonary collaterals . These collaterals develop in patients with atresia or hypoplasia of the central pulmonary arteries and function to bring blood to the lungs. (Right) Axial CTA in the same patient shows the aorta (Ao) overriding the interventricular septum. Note the membranous type VSD and right ventricular hypertrophy due to pulmonary artery infundibular stenosis.

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(Left) Axial oblique CECT shows mild long-segment narrowing of the right main pulmonary artery. The aortic arch is right sided. (Right) Oblique CECT in the same patient shows right ventricular hypertrophy, a membranous ventricular septal defect , and an aorta that overrides the interventricular septum. The combination of these 4 main findings constitutes tetralogy of Fallot. P.2:74

(Left) Axial black blood SE image demonstrates large membranous VSD and markedly thickened RV myocardium , similar in thickness to LV myocardium. Note the enlarged aorta overriding the VSD. (Right) Axial SE image in the same patient demonstrates enlarged aorta and atretic pulmonary artery with tiny pulmonary valve remnant (not shown). Large arterial branches arise from descending thoracic aorta to perfuse lungs, consistent with TOF with pulmonary atresia (pseudotruncus).

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(Left) PA radiograph in an adult with untreated tetralogy of Fallot demonstrates a right aortic arch , a narrow vascular neck due to pulmonary atresia, and an elevated cardiac apex, resulting in the classic coeur en sabot appearance. (Right) RVOT SSFP MR in a different patient post pulmonary valvotomy shows a spin-dephasing flow void jet of pulmonic regurgitation. MR used to guide the timing of pulmonary valve replacement by quantifying pulmonic regurgitant fraction and right ventricular function.

(Left) Frontal radiograph in a cyanotic 2-day-old patient shows decreased pulmonary blood flow. The major differential considerations include tetralogy of Fallot and other lesions with central pulmonary artery stenosis and an unrestricted right-to-left shunt (ASD or VSD). (Right) Coronal CECT in the same patient shows uplifting of the left ventricular apex due to right ventricular hypertrophy. The main pulmonary artery is diminutive . P.2:75

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(Left) Frontal radiograph shows a hypoplastic left lung with ipsilateral mediastinal shift due to an interrupted (absence of proximal) left pulmonary artery. Note the right-sided aortic arch and the left upper lung cavity with mycetoma. (Right) Axial CECT in the same patient shows an interrupted left pulmonary artery, which always occurs contralateral to the aortic arch. The image shows a right-sided descending thoracic aorta and a persistent left superior vena cava .

(Left) Axial CECT in the same patient shows right ventricular outflow tract narrowing and marked right ventricular muscular hypertrophy. Note that the mediastinum is shifted toward the left due to small left lung secondary to an interrupted pulmonary artery. Note the right-sided descending thoracic aorta . (Right) Frontal radiograph in a newborn with tetralogy of Fallot shows decreased-to-normal pulmonary vascularity and an uplifted cardiac apex indicating right ventricular hypertrophy.

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(Left) Axial CECT shows a rare variant of tetralogy of Fallot with absent pulmonic valve leaflets. Note the overriding aorta and right ventricular dilation . (Right) Coronal CECT in the same patient shows marked dilation of the right and left main pulmonary arteries due to absent pulmonary valve leaflets. Patients with this variant have an enlarged right ventricle and main pulmonary arteries due to free pulmonic regurgitation.

Tetralogy of Fallot Palliation: BT Shunt Tetralogy of Fallot Palliation: BT Shunt Jonathan Hero Chung, MD Key Facts Terminology  Palliative procedure to increase pulmonary blood flow  Original shunt sacrifices subclavian artery (distal ligation) o Proximal portion of subclavian artery routed inferiorly to end-to-side anastomosis with ipsilateral branch pulmonary artery  Modified Blalock-Taussig shunt uses synthetic graft, usually polytetrafluoroethylene (Gore-Tex) o Proximal anastomosis is end-to-side between graft (end) and subclavian artery or brachiocephalic trunk (side) o Distal anastomosis is end-to-side between distal graft (end) and ipsilateral pulmonary artery (side) Imaging  CT o Tubular contrast-filled structure connecting subclavian and ipsilateral pulmonary arteries o Occluded shunts are difficult to visualize due to absence of contrast; multiplanar reconstructions are helpful o Excellent tool for detection of aortopulmonary collaterals prior to definitive repair  MR/MRA o Same imaging manifestations as CT o Phase-contrast imaging capability allows quantification of flow dynamics  Complications o Subclavian artery occlusion distal to graft anastomosis o Shunt occlusion in 11% of cases o Perigraft seroma in 2.5-9.5% of cases Top Differential Diagnoses  Other forms of Tetralogy palliation o Waterston-Cooley shunt o Potts shunt

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(Left) Graphic shows a modified Blalock-Taussig (BT) shunt connecting the subclavian artery (SCA) and pulmonary artery. Note the original BT shunt with the distal ligated SCA. Mobilized proximal SCA is anastomosed to the pulmonary artery. (Right) Coronal image from CTA shows stenosis at the pulmonary artery branch confluence and patent right-sided modified BT shunt (proximal anastomosis to brachiocephalic trunk) in a patient with tetralogy of Fallot.

(Left) Coronal MRA shows a BT shunt between the right subclavian artery and the right pulmonary artery in a patient with history of tetralogy of Fallot. The distal aspect of the BT shunt is narrow . (Courtesy J. Kirsch, MD.) (Right) Coronal MIP image from MRA in a patient with tetralogy Fallot and occluded BT shunts shows multiple serpiginous aortopulmonary collateral arteries in the mediastinum. (Courtesy J. Kirsch, MD.) P.2:77

TERMINOLOGY Abbreviations  Blalock-Taussig (BT) Synonyms  Blalock-Taussig shunt, Blalock-Taussig procedure, “blue baby” operation Definitions  Palliative procedure to increase pulmonary blood flow  Original shunt sacrifices subclavian artery (distal ligation) o First performed in November 1944 at Johns Hopkins University Hospital o Proximal portion of subclavian artery routed inferiorly to end-to-side anastomosis with ipsilateral branch pulmonary artery 184

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Alfred Blalock (1899-1964)  1st surgeon to perform procedure o Helen Taussig (1898-1986)  Pediatric cardiologist who designed shunt  Modified BT shunt uses synthetic graft, usually polytetrafluoroethylene (Gore-Tex) o Proximal anastomosis is end-to-side between graft (end) and subclavian artery or brachiocephalic trunk (side) o Distal anastomosis is end-to-side between distal graft (end) and ipsilateral pulmonary artery (side) IMAGING General Features  Complications o Subclavian artery occlusion distal to graft anastomosis o Shunt occlusion in 11% of cases  More common in smaller grafts (4 mm) o Perigraft seroma in 2.5-9.5% of cases  Definitive repair usually follows in early childhood o VSD closure and Dacron patch relieve right ventricular outflow tract obstruction Radiographic Findings  Increased pulmonary blood flow  Rib notching ipsilateral to traditional shunt CT Findings  Tubular contrast-filled structure connecting subclavian and ipsilateral pulmonary arteries o Occluded shunts are difficult to visualize due to absence of contrast; multiplanar reconstructions are helpful  Excellent tool for detection of aortopulmonary collaterals prior to definitive repair MR Findings  Extra tubular flow void structure connecting subclavian and ipsilateral pulmonary artery o Bright signal on gradient echo or SSFP sequences o May contain high signal on spin echo or FSE or low signal on SSFP if occluded  Perigraft seroma: T1 iso- and T2 hyperintense upper mediastinal collection with flow void (if patent shunt)  May demonstrate chest wall collaterals if traditional BT or subclavian occlusion distal to graft anastomosis  Phase-contrast imaging allows quantification of flow dynamics Echocardiographic Findings  May demonstrate graft patency and pressure gradients across graft ± stenosis  Turbulent flow entering right or left pulmonary artery DIFFERENTIAL DIAGNOSIS Other Forms of Tetralogy Palliation  Waterston-Cooley shunt o Ascending aorta to right pulmonary artery  Potts shunt o Descending aorta to left pulmonary artery (no longer performed) DIAGNOSTIC CHECKLIST Consider  Aortopulmonary collateral arteries may develop if otherwise insufficient pulmonary blood flow SELECTED REFERENCES 1. Moszura T et al: Late emergency arterial duct stenting in a patient with tetralogy of Fallot and occluded BlalockTaussig shunt. Cardiol J. 18(1):87-9, 2011 2. Kim SW et al: Tetralogy of fallot patient who underwent a classic Blalock-Taussig shunt in 1962. J Card Surg. 25(6):745-6, 2010 3. Yuan SM et al: The Blalock-Taussig shunt. J Card Surg. 24(2):101-8, 2009 4. Peries A et al: Outcome of the construction of a Blalock-Taussig shunt in adolescents and adults. Cardiol Young. 15(4):368-72, 2005 5. Maghur HA et al: The modified Blalock-Taussig shunt: a 6-year experience from a developing country. Pediatr Cardiol. 23(1):49-52, 2002 6. Quek SC et al: Thrombotic obstruction of modified Blalock-Taussig shunt. Cardiol Young. 12(4):391, 2002 7. Rana JS et al: Blalock-Taussig shunt: experience from the developing world. Heart Lung Circ. 11(3):152-6, 2002 8. van Rijn RR et al: Development of a perigraft seroma around modified Blalock-Taussig shunts: imaging evaluation. AJR Am J Roentgenol. 178(3):629-33, 2002 185

Diagnostic Imaging Cardiovascular 9. Coren ME et al: Complications of modified Blalock-Taussig shunts mimicking pulmonary disease. Arch Dis Child. 79(4):361-2, 1998 10. Hofbeck M et al: Color Doppler imaging of modified Blalock-Taussig shunts during infancy. Pediatr Cardiol. 15(6):163-6, 1994 11. Ichida F et al: [Magnetic resonance imaging: evaluation of the Blalock-Taussig shunts and anatomy of the pulmonary artery] J Cardiol. 22(4):669-78, 1992 12. Kastler B et al: Magnetic resonance imaging in congenital heart disease of newborns: preliminary results in 23 patients. Eur J Radiol. 10(2):109-17, 1990 13. Ullom RL et al: The Blalock-Taussig shunt in infants: standard versus modified. Ann Thorac Surg. 44(5):539-43, 1987 14. Sakuma I et al: [An application of X-ray computed tomography for complex cardiac anomalies] J Cardiogr. 13(3):699-713, 1983 15. Blalock A et al: The surgical treatment of malformation of the heart in which there is pulmonary stenosis or pulmonary atresia. JAMA. 128(3):189-202, 1945

Tetralogy of Fallot: Definitive Repair Tetralogy of Fallot: Definitive Repair Suhny Abbara, MD, FSCCT Cameron Hassani, MD Key Facts Terminology  Closure of ventricular septal defect and repair of right ventricular outflow tract (RVOT) obstruction o Ventricular septal defect repair with prosthetic patch graft o RVOT obstruction repair with transannular patch ± division/resection of obstructing muscle bundles o Occasionally, tube graft from RVOT patch or right atrium to pulmonary artery (Rastelli procedure) o Previous palliative shunts (Blalock-Taussig, Waterston-Cooley, etc.) are usually taken down at time of definitive repair  Imaging is used to evaluate complications related to repair o Pulmonic regurgitation (PR) o Residual ventricular or atrial septal defect Imaging  Right ventricular dilatation + increased myocardial thickness  Dextroposed aorta overriding interventricular septum  Calcified patch spanning malaligned ventricular septal defect from muscular septum to right aspect of aortic annulus  Hyperenhancement usually seen at site of RVOT patch repair  MR is best diagnostic tool for evaluation of PR  MR is best overall tool for serial follow-up post tetralogy of Fallot repair to evaluate for complications when patients reach adolescence  Echocardiography is best for intracardiac assessment of ventricular septal defect  CTA is best for detecting branch pulmonary stenosis and multiple aortopulmonary collateral arteries

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Diagnostic Imaging Cardiovascular (Left) Graphic shows definitive tetralogy of Fallot repair with ventricular septal defect (VSD) patch and right ventricular outflow tract (RVOT) patch plasty . Preexisting palliatively placed Blalock-Taussig shunts are typically ligated at the time of definitive repair. (Right) AP chest scout view in a patient with repaired tetralogy of Fallot shows a unilaterally enlarged left pulmonary artery , a Carpentier-Edwards bioprosthetic pulmonic valve replacement , and a right aortic arch .

(Left) Oblique cardiac CT status post definitive repair of tetralogy of Fallot shows right ventricular (RV) hypertrophy, a VSD repair patch with small calcification , and a dextroposed aorta overriding the ventricular septum. (Right) Axial CECT in the same patient shows a partially calcified RVOT patch extending across the pulmonic valve area. There are multiple weblike stenoses in the main pulmonary artery and its branches. Note right-sided descending thoracic aorta. P.2:79

TERMINOLOGY Abbreviations  Tetralogy of Fallot (TOF) Definitions  Closure of ventricular septal defect (VSD) and repair of right ventricular outflow tract (RVOT) obstruction o VSD repair with prosthetic patch graft  Accomplished via atrial incision ± ventriculotomy o RVOT obstruction repair with transannular patch ± division/resection of obstructing muscle bundles  Occasionally, tube graft from RVOT patch or right atrium (RA) to pulmonary artery (PA) (Rastelli procedure)  Semilunar pericardial allograft pulmonic valve repair or pulmonary valve-sparing approaches may be chosen in some cases o Previous palliative shunts (Blalock-Taussig, Waterston-Cooley, etc.) are usually taken down at time of definitive repair  Imaging is used to evaluate complications related to repair o Pulmonic regurgitation (PR)  Considered most important complication due to treatability and contribution to development of majority of long-term complications  Results in right ventricular (RV) dilatation, dysfunction, arrhythmia, heart failure, and sudden death  Nearly always present; however, can be reversed if treated with pulmonic valve replacement  Imaging is used to assess threshold values of indexed RV size, ejection fraction, and regurgitant fraction as criterion for surgery o Residual VSD or atrial septal defect o Residual pulmonic stenosis  Can involve RVOT to distal branches o Tricuspid regurgitation 187

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RVOT aneurysm RV fibrosis

IMAGING General Features  Best diagnostic clue o Normal appearance status post definitive repair  Calcified, nonenhancing patch between muscular ventricular septum and overriding aortic annulus (VSD repair)  Occasionally hyperdense pledgets may be noted  Thin and relatively deformed RVOT (secondary to surgical resection of muscle bundles) potentially spanning into PA (± calcifications, hyperdense material)  Remainder of RA usually demonstrates thickened myocardium from RV hypertrophy  Occasionally hypoplastic PA with tube graft connecting RA to distal main PA  Right atriotomy scar Radiographic Findings  RV hypertrophy with filling of retrosternal clear space  May demonstrate calcifications along anterior RV wall on lateral radiograph  May show systemic aortopulmonary collaterals CT Findings  CTA o Use CT when MR is contraindicated o High-density material at RVOT corresponds to patch and is potentially transannular, spanning into PA  May have pledgets at suture site  May calcify  Patch is usually much thinner than native RV or RVOT tissue o RV dilatation + increased myocardial thickness o Dextroposed aorta overriding interventricular septum o Calcified patch spanning malaligned VSD from muscular septum to right aspect of aortic annulus  Best seen on oblique left ventricular long-axis view  May demonstrate hyperdense pledgets at suture sites o ± native PA stenoses o ± aortopulmonary systemic collateral arteries o CTA may show tube graft from RVOT patch or RA to distal main PA  Cardiac gated CTA o Preferred in adults because of motion-free imaging of both intra- and extracardiac structures o Allows for calculation of RV function parameters MR Findings  Best modality for serial follow-up post TOF repair complications  Best diagnostic tool for evaluation of PR, RV size, and RV function o Degree of PR increases over time and makes MR best tool for longitudinal follow-up  SSFP cine o Pulmonic regurgitation  Signal void/jet of residual VSD  Report end-diastolic and end-systolic indexed values  Good post-repair results are reported when repair is performed before RV end diastolic volume index (EDVi) ≤ 200  MRA similar to CTA  Perfusion MR shows patches as nonenhancing low-intensity structures  MR is best tool for RV functional assessment o Ejection fraction, end-systolic and end-diastolic volumes, muscle mass, and regional wall motion abnormalities  Phase-contrast cine images o Quantify pulmonic regurgitant fraction  Delayed enhancement o Hyperenhancement usually seen at site of RVOT patch repair o Abnormal hyperenhancement indicates ventricular fibrosis 188

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Fibrosis in adults correlates with markers of adverse clinical outcome, including ventricular dysfunction, exercise intolerance, and neurohormonal activation o Associated with arrhythmias Echocardiographic Findings  Routine imaging tool of choice for TOF repair follow-up  PR of varying degree P.2:80 

Isolated RV restriction late after repair in > 50% of patients o A-wave contributes to PA forward flow and shortens duration of regurgitation, resulting in relatively decreased cardiomegaly and improved exercise performance in patients with restriction o Antegrade pulmonary flow during atrial systole o Augmented during inspiration Angiographic Findings  Invasive but may allow interventions o Balloon angioplasty of branch pulmonary stenoses Imaging Recommendations  Best imaging tool o MR: Overall best modality for serial follow-up to evaluate for complications when patients reach adolescence o Echocardiography: Best for intracardiac assessment of VSD o CTA: Best for detection of branch pulmonary stenosis and multiple aortopulmonary collateral arteries (MAPCAs) CLINICAL ISSUES Presentation  Most common signs/symptoms o Repair of RVOT obstruction results in  Disruption and loss of normal pulmonic valve function resulting in PR Natural History & Prognosis  High survival in 1st 2 decades post repair; however, survival drops considerably in 3rd decade due to longterm complications o Long-term complications include arrhythmias, heart failure, RV function deterioration, PR, and PA stenosis  Arrhythmias may be due to RVOT myotomies or muscle bundle resection or due to severe PR and RV dilatation  Atrial flutter is more common than atrial fibrillation  Ventricular arrhythmias may be self-limited or may require treatment o May lead to sudden cardiac death o Treatment may necessitate radiofrequency ablation o ± implantable cardioverter defibrillator  RV dilatation are functional and exercise deterioration are usually due to PR o Symptoms of RV volume overload may be inapparent until significant RV failure is present o Timing of pulmonic valve replacement is increasingly performed using MR-derived quantitative analysis of RV end-diastolic volumes  Optimal timing for surgical pulmonic valve repair is when normalized RV end-diastolic volume is > 150mL/m2 or 160mL/m2 and < 200mL/m2  Aortic root dilatation is common in adults with remote repair of TOF o In observational study of 109 adults, 21% of aortic roots were ≥ 4.5 cm, 8% were ≥ 5 cm, and 2% were ≥ 5.5 cm o ˜ 2% will require aortic valve or root replacement o Rarely, dissection may occur  Pregnancy may be feasible in some cases with modern TOF repairs Treatment  Pulmonary stenoses may be balloon dilated o MAPCAs are occasionally coiled at same time  Ventricular arrhythmia treatments include medical therapy, device/resynchronization therapy, and percutaneous intervention 189

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Severe PR may be repaired with elective pulmonary valve replacement o Benefit is controversial o Should be performed before irreversible RV dysfunction ensues DIAGNOSTIC CHECKLIST Consider  Volume rendering of CTA or MRA for anatomic PA and RVOT anatomy assessment  Cine MR is best tool for RV and pulmonic valve function assessment  Gated CTA in adults allows for accurate volumetric chamber assessment o Bets performed with low-dose (80 kVp) retrospective gated acquisition  Check for late complications o Branch pulmonary stenosis o Aortopulmonary systemic collaterals o RV dysfunction due to PR o Aortic root aneurysm and dissection Reporting Tips  MR report should include o Quantification of right and left ventricular end-systolic volume, end-diastolic volume, stroke volume, and ejection fraction o Quantification of PR, tricuspid regurgitation, and ratio of pulmonic to systemic flow o Regional wall motion abnormalities SELECTED REFERENCES 1. Nagy CD et al: Tetralogy of fallot and aortic root dilation: a long-term outlook. Pediatr Cardiol. 34(4):809-16, 2013 2. Aboulhosn J et al: Management after childhood repair of tetralogy of fallot. Curr Treat Options Cardiovasc Med. 8(6):474-83, 2006 3. Babu-Narayan SV et al: Ventricular fibrosis suggested by cardiovascular magnetic resonance in adults with repaired tetralogy of fallot and its relationship to adverse markers of clinical outcome. Circulation. 113(3):405-13, 2006 4. Grothoff M et al: Pulmonary regurgitation is a powerful factor influencing QRS duration in patients after surgical repair of tetralogy of Fallot. A magnetic resonance imaging (MRI) study. Clin Res Cardiol. 95(12):643-9, 2006 5. Kleinveld G et al: Hemodynamic and electrocardiographic effects of early pulmonary valve replacement in pediatric patients after transannular complete repair of tetralogy of Fallot. Pediatr Cardiol. 27(3):329-35, 2006 6. Norton KI et al: Cardiac MR imaging assessment following tetralogy of fallot repair. Radiographics. 26(1):197-211, 2006 7. Oosterhof T et al: Corrected tetralogy of Fallot: delayed enhancement in right ventricular outflow tract. Radiology. 237(3):868-71, 2005 8. Therrien J et al: Optimal timing for pulmonary valve replacement in adults after tetralogy of Fallot repair. Am J Cardiol. 95(6):779-82, 2005 P.2:81

Image Gallery

(Left) Axial cardiac CT in a patient with remote definitive repair of tetralogy shows an enlarged aortic root 190

, a right-

Diagnostic Imaging Cardiovascular sided descending thoracic aorta , and a patch plasty repair of pulmonic or subpulmonic stenosis, best identified by the presence of patch calcification. (Right) Axial cardiac CT shows a VSD repair patch . Note noncoronary cusp , right coronary cusp of aorta, left ventricular outflow tract , and enlarged RV due to pulmonic insufficiency.

(Left) Axial cardiac CT in the same patient status post definitive repair of tetralogy of Fallot shows enlarged right ventricle and atrium due to longstanding pulmonic insufficiency/regurgitation. Note that the aorta is overriding the ventricular septum. (Right) Paraseptal long-axis view of the right ventricle shows enlarged right ventricle and atrium. Note the calcified VSD patch separating the right ventricle from the left ventricular outflow tract . Also note the RVOT patch with minimal calcification.

(Left) Axial FSE MR shows enlarged aortic root and right-sided descending thoracic aorta in a patient with definitive repair of tetralogy of Fallot. Note thickened left ventricular outflow tract myocardium (RV hypertrophy), except for an area corresponding to the patch repair . (Right) Axial FSE MR in the same patient shows marked RV hypertrophy , an overriding aorta, and a VSD patch repair . Also note the right-sided descending thoracic aorta and right atrial enlargement. P.2:82

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(Left) Short-axis MR SSFP in diastole in a patient after definitive repair of tetralogy demonstrates typical appearance of RV muscular hypertrophy, with much thinner appearance of the RV wall at the RVOT patch repair site . (Right) Short-axis MR SSFP in systole in the same patient shows straightening of the ventricular septum and thickening of the RV myocardium but also characteristic unchanged thickness and absence of contraction of the RVOT patch .

(Left) Short-axis DE MR in a patient after definitive repair of tetralogy with patch repair of the RVOT demonstrates abnormal delayed enhancement of the thinned RVOT patch repair site . (Right) PA and lateral radiographs show bioprosthetic pulmonic valve replacement (Mitroflow valve). MR may be used to optimize the timing of surgery, and 2 RV end-diastolic normalized volume of 150 mL/m has been used as a cutoff to indicate surgery.

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(Left) Axial SSFP MR in a patient status post definitive repair of TOF and right aortic arch shows right descending thoracic aorta and marked pulmonary arterial enlargement . (Right) Axial SSFP MR demonstrates markedly enlarged right and left central pulmonary arteries and a bioprosthetic pulmonic valve in situ. Also note right descending thoracic aorta. Patient had definitive repair of tetralogy of Fallot with decades of pulmonic insufficiency. P.2:83

(Left) Axial CTA in a patient with definitive repair of tetralogy of Fallot demonstrates an ascending aortic aneurysm with a focal type A aortic dissection. Note true lumen separated by a flap from the false lumen . (Right) Coronal CTA in the same patient demonstrates the overriding aorta with a partially calcified VSD patch repair , ascending aortic aneurysm , and false lumen separated by a focal dissection flap from the true lumen.

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(Left) Axial cardiac CT in a patient with definitive repair of tetralogy of Fallot shows RVOT patch plasty with minimal calcification and a deformed pulmonic valve with a regurgitant orifice visible . Note ascending aortic aneurysm . (Right) PA radiograph in a patient with tetralogy of Fallot shows cardiomegaly and St. Jude bileaflet tilting disc valve repairs of both the aortic valve and the pulmonic valve , respectively.

(Left) Lateral radiograph in the same patient shows normal positions of the aortic and pulmonic mechanical valve prostheses. Note decrease of the retrosternal clear space due to RV enlargement. (Right) Paraseptal RV long-axis view cardiac CT in systole in the same patient demonstrates normal positions and systolic function of the bileaflet tilting disc valves in the aortic and pulmonic positions.

Proximal Interruption of Pulmonary Artery Proximal Interruption of Pulmonary Artery Carol C. Wu, MD Tyler H. Ternes, MD Key Facts Terminology  Proximal interruption of pulmonary artery (PIPA)  Failed development of proximal pulmonary artery Imaging  Radiography o Small ipsilateral lung and hilum o Aortic arch contralateral to interrupted pulmonary artery  CT 194

Diagnostic Imaging Cardiovascular o Absence or early termination of proximal pulmonary artery o Enlarged ipsilateral collateral intercostal, bronchial, internal mammary, and subclavian arteries o Contralateral aortic arch o Normal bronchial branching pattern o Subpleural reticular opacities o Compensatory hyperinflation of contralateral lung Top Differential Diagnoses  Swyer-James-McLeod syndrome  Scimitar syndrome Pathology  Left PIPA: Higher incidence of congenital cardiovascular anomalies Clinical Issues  Symptoms/signs o Recurrent pulmonary infection o Hemoptysis o Pulmonary arterial hypertension o Can be asymptomatic if isolated  Prognosis o Determined by associated cardiac anomalies and pulmonary arterial hypertension

(Left) PA chest radiograph of a patient with proximal interruption of pulmonary artery (PIPA) shows a small right hilum and a small right lung with compensatory hyperinflation of the left lung. As in this case, the aortic arch is typically contralateral to the interrupted pulmonary artery. (Right) Axial CECT of the same patient shows interruption of the right pulmonary artery at its expected origin . Serrated right pleural thickening is produced by enlarged intercostal artery branches supplying the lung.

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(Left) Axial CECT of the same patient shows a hypoplastic right lung with subtle peripheral reticular opacities related to systemic collateral vessels supplying the lung. Bronchiectasis is a frequent finding related to recurrent pulmonary infections. (Right) Axial CECT of the same patient shows bilateral mosaic attenuation. Ipsilateral hypoattenuation is likely due to hypoperfusion. Contralateral areas of hypoattenuation may be due to surrounding overperfusion. P.2:85

TERMINOLOGY Abbreviations  Proximal interruption of pulmonary artery (PIPA) Synonyms  Unilateral absence of pulmonary artery o “Interruption” preferred over “absence”  Intrapulmonary portion of pulmonary artery is intact Definitions  Failed development of proximal pulmonary artery IMAGING General Features  Best diagnostic clue o Small hilum with small ipsilateral lung o Contralateral aortic arch  Location o Right > left Radiographic Findings  Radiography o Affected hemithorax  Volume loss with ipsilateral mediastinal shift and hemidiaphragm elevation  Small or indistinct hilum  Fine subpleural reticular opacities  Systemic collateral vessels along pleura and within lung  Rib notching (intercostal collaterals) o Unaffected hemithorax  Compensatory hyperinflation and relative hyperlucency of contralateral lung  Enlarged hilum from increased blood flow o Aortic arch typically on opposite side of interrupted pulmonary artery o ± cardiomegaly due to associated cardiac anomalies and pulmonary arterial hypertension CT Findings  CECT o Proximal pulmonary artery may be completely absent or terminate within 1 cm of origin o Normal bronchial branching pattern 196

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Signs of collateral circulation  Enlarged ipsilateral collateral arteries  Internal mammary, bronchial, intercostal, subclavian  Serrated pleural thickening: Enlarged intercostal artery branches  Reticular subpleural opacities perpendicular to pleural surface: Anastomoses of transpleural systemic vessels with distal pulmonary arteries  Unilateral rib notching o ± pulmonary arterial hypertension  Dilatation of main and contralateral pulmonary arteries Nuclear Medicine Findings  V/Q scan o No perfusion of affected side  Affected lung exclusively perfused from systemic collateral arteries o Normal ventilation Imaging Recommendations  Best imaging tool o CECT is optimal for evaluation of pulmonary arteries and collaterals DIFFERENTIAL DIAGNOSIS Swyer-James-McLeod Syndrome  Obliterative bronchiolitis in infant or child  Unilateral hyperlucent lung with small ipsilateral pulmonary artery o In PIPA, affected small lung is more opaque than contralateral hyperinflated lung  Expiratory air trapping Scimitar Syndrome  Right lung hypoplasia o Underdevelopment of central airways and vasculature o 1 or more lobes may be absent  Anomalous pulmonary vein descends vertically, usually drains into inferior vena cava PATHOLOGY General Features  Etiology o Involution of proximal 6th primitive arch  Intrapulmonary vessels remain intact  Associated abnormalities o Left PIPA has higher incidence of associated congenital cardiovascular anomalies  Most common: Tetralogy of Fallot CLINICAL ISSUES Presentation  Most common signs/symptoms o Pulmonary infections o Dyspnea o Hemoptysis o Pulmonary arterial hypertension o May be asymptomatic Demographics  Epidemiology o Estimated prevalence of 1 in 200, 000 Natural History & Prognosis  Determined by associated cardiac anomalies or pulmonary arterial hypertension Treatment  Revascularization of interrupted artery in infancy  Embolization of systemic collaterals for hemoptysis SELECTED REFERENCES 1. Dillman JR et al: Expanding upon the unilateral hyperlucent hemithorax in children. Radiographics. 31(3):723-41, 2011 2. Castañer E et al: Congenital and acquired pulmonary artery anomalies in the adult: radiologic overview. Radiographics. 26(2):349-71, 2006 P.2:86 197

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Image Gallery

(Left) PA chest radiograph of an asymptomatic patient with proximal interruption of the left pulmonary artery shows a small left lung, a small left hilum , a right aortic arch , and a shift of the mediastinal structures to the left. (Right) Lateral chest radiograph of the same patient demonstrates absence of the left pulmonary artery . The mediastinum is shifted posteriorly due to rotation of the mediastinum and anterior herniation of the hyperinflated right lung.

(Left) Coronal NECT of the same patient shows that the right pulmonary artery is larger than the aortic arch . This suggests pulmonary hypertension, which is often found in patients with PIPA. (Right) Axial NECT of the same patient shows marked mediastinal shift to the left due to left lung hypoplasia. The left pulmonary artery is interrupted , and the right lung herniates across the midline due to compensatory hyperinflation.

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(Left) Composite image with PA (left) and lateral (right) chest radiographs of a patient with proximal interruption of the left pulmonary artery shows absence of the left pulmonary artery . This case illustrates an uncommon variant in that the aortic arch is ipsilateral to the interrupted artery. (Right) Axial CECT of the same patient shows interruption of the left pulmonary artery and left lung consolidation . Recurrent pneumonia commonly affects the hypoplastic lung. P.2:87

(Left) Axial CECT maximum-intensity projection (MIP) shows asymmetric blood supply to the lungs. The left lung is supplied by bronchial and intercostal collateral vessels. (Right) Coronal CECT MIP of the same patient shows enlarged bronchial arteries supplying the hypoplastic left lung due to proximal interruption of the left pulmonary artery. There is dilatation of the right pulmonary artery . Patients with PIPA may develop pulmonary arterial hypertension.

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(Left) Frontal pulmonary artery angiography of a patient with proximal interruption of the left pulmonary artery shows an enlarged right pulmonary artery and nonvisualization of the left pulmonary artery. (Right) Frontal angiography of a patient with hemoptysis and interrupted right pulmonary artery shows multiple enlarged systemic collateral arteries supplying the right lung. Angiography and embolization may be required to treat recurrent or severe hemoptysis.

(Left) Anterior projection from a perfusion scintigram shows absence of perfusion to the right lung secondary to proximal interruption of the right pulmonary artery. (Right) Axial T2WI MR shows a normal pulmonary trunk, a normal left pulmonary artery, and a proximal interruption of the right pulmonary artery . MR imaging may be obtained in patients with PIPA to evaluate associated congenital cardiac abnormalities.

Section 3 - Shunts Approach to Shunts Approach to Shunts Carlos Rojas, MD Intracardiac Shunts An intracardiac shunt results from an abnormal communication between the pulmonary and systemic circulations at the level of the heart, which results in mixing of venous and arterial blood. Shunting occurs from the higher pressure system to the lower pressure system. Isolated intracardiac communications (atrial septal defects [ASDs] and ventricular septal defects [VSDs]) typically result in left-to-right flow and may elude detection for many years. Conversely, intracardiac communications resulting in right-to-left flow are detected earlier due to the presence of 200

Diagnostic Imaging Cardiovascular cyanosis. Longstanding left-to-right shunts can increase the right-sided pressures and can therefore eventually result in reversal of flow through the shunt and then cause cyanosis (Eisenmenger syndrome). Intracardiac shunts may be congenital or acquired with congenital defects resulting from abnormal morphogenesis of the atrial or ventricular septae. Intracardiac shunts are the most common congenital heart defects. Acquired shunts result from infection or trauma or are iatrogenic. Although shunts are typically detected and characterized by echocardiography, the role of MR and cardiac CT is growing due to their excellent anatomic depiction of the defect and its margins, accurate evaluation of right ventricular volumes and function, and detection of associated anomalies. Cardiac MR with the use of phase-contrast imaging can quantify blood flow in the systemic and pulmonary systems, allowing one to determine the degree of shunting. A pulmonary to systemic flow ratio (Qp:Qs) > 1.5 is considered significant and can result in right heart overload and failure. Of note, cardiac CT does not allow direct flow quantification and exposes the patient to ionizing radiation; therefore, it is used only in cases of inadequate echocardiogram and when MR is contraindicated. Treatment options depend on multiple factors, including the patient's symptoms, ventricular volumes and function, pulmonary arterial pressure, Qp:Qs ratio, location of the defect, size of the defect and surrounding septae, number of defects, associated anomalies, and others. Types of Intracardiac Shunts Arial Septal Defects ASDs result from abnormal communication at the level of the atria. They may be single or multiple and can vary in size and shape. Depending on the location of the interatrial communication, an ASD can be classified as ostium secundum, ostium primum, sinus venosus, or unroofed coronary sinus. ASDs result in enlargement of the right atrium, right ventricle, and pulmonary arteries. Ostium secundum ASD is the most common classification and accounts for 75% of all ASDs. This defect is centered in the fossa ovalis and results from excessive apoptosis of the septum primum or incomplete formation of the septum secundum. Ostium primum ASD accounts for 15-20% of ASDs. This defect is considered the mildest form of an endocardial cushion defect and results from failed fusion between the free edge of the septum primum and the atrioventricular cushions. This defect is located immediately adjacent to the mitral valve annulus. Sinus venosus ASD accounts for 5-10% of all ASDs. This defect is located either in the superior interatrial septum or in the inferior interatrial septum. A superior sinus venosus ASD is typically associated with partial anomalous pulmonary venous return of the right upper &/or right middle lobe into the superior vena cava. An inferior sinus venosus ASD may be associated with partial anomalous pulmonary venous return to the intrapericardial segment of the inferior vena cava or right atrium. Unroofed coronary sinus ASD is the rarest classification of ASD and accounts for < 1% of all ASDs. This defect results from abnormal septation between the left atrium and the adjacent coronary sinus. Although the interatrial septum is intact, this defect results in shunting at the atrial level through the coronary sinus (left atrium to coronary sinus to right atrium) and is therefore considered an ASD. Ventricular Septal Defects VSDs result from abnormal communication at the level of the ventricles. These defects are the most common congenital abnormality found in children and may close spontaneously in a large percentage of patients. VSDs may be single or multiple and can vary in size and shape. Depending on their location, they can be classified as perimembranous, subarterial, muscular, and inflow. VSDs result in enlargement of the right ventricle, pulmonary artery, left atrium, and left ventricle. Perimembranous VSD is the most common classification and accounts for 80% of all VSDs. This type of defect is located below the crista supraventricularis, anterior to the septal leaflet of the tricuspid valve, and is bounded by muscular and membranous septum. This defect may close spontaneously by apposition of the septal leaflet of the tricuspid valve. Subarterial VSD accounts for 5% of all VSDs. This defect is located above the crista supraventricularis and is bounded by the fibrous annulus of the semilunar valve &/or muscular tissue. Because of its location, a subarterial VSD may be associated with aortic valve prolapse and regurgitation. Muscular VSD accounts for 10% of all VSDs. This defect is located in the trabecular portion of the interventricular septum; therefore, the defect is bounded only by muscle. Inflow VSD accounts for 5% of all VSDs and is almost exclusively associated with endocardial cushion defects. This defect is located anterior to the tricuspid valve annulus and extends to the muscular &/or membranous septum. Endocardial Cushion Defects Endocardial cushion defects, also known as atrioventricular canal defects, are secondary to abnormal development of the endocardial cushion, which results in a spectrum of interatrial and interventricular communications associated with atrioventricular valve abnormalities. In turn, endocardial cushion defects result in enlargement of the right atrium, right ventricle, pulmonary artery, left atrium, and left ventricle. 201

Diagnostic Imaging Cardiovascular Partial atrioventricular canal defect results in a defect in the anterior and inferior aspect of the atrial septum (i.e., an ostium primum ASD) associated with a cleft in the anterior leaflet of the mitral valve. Intermediate atrioventricular canal defect results in a defect in the anterior and inferior aspect of the atrial P.3:3 septum (i.e., an ostium primum ASD), a small inlet VSD, and a cleft in the mitral and tricuspid valves. Complete atrioventricular canal defect results in a large defect in the anterior and inferior aspect of the atrial septum, a large VSD, and a common atrioventricular valve. Embryology The development of the interatrial septum starts during the fifth week of gestational life. The common atrium divides into left and right atria through the formation of two separate overlapping septae (i.e., septum primum and septum secundum). Interatrial communication during fetal life is normal through the foramen ovale. However, persistence of interatrial communication beyond the first months of life as a valve mechanism is abnormal and occurs in approximately 30% of the population; this condition is known as a patent foramen ovale. Deficient morphogenesis of the septum primum or septum secundum results in an ASD. The development of the interventricular septum starts during the fifth week of gestational life. The common ventricle divides into left and right ventricles through the fusion of three independent septae (i.e., muscular septa, outlet septa, and inlet septa). Incomplete fusion of these septae results in a VSD. The endocardial cushions are responsible for the formation of the inferior and anterior portion of the interatrial septum, the inlet portion of the ventricular septum, and the atrioventricular valves. Incomplete development of the endocardial cushions results in a spectrum of abnormalities ranging from an ostium primum ASD with a cleft mitral valve (i.e., partial atrioventricular canal defect) to a common atrioventricular valve with a large atrial and ventricular septal defects (i.e., complete atrioventricular canal defect). Clinical Implications Small isolated intracardiac shunts may be asymptomatic for many years and only incidentally detected on physical exam. In contrast, large shunts present early with shortness of breath, exercise intolerance, palpitations, syncope, and heart failure. Shunt complications include pulmonary arterial hypertension, right-sided heart failure, arrhythmias, stroke from paradoxical embolism, and Eisenmenger syndrome. Treatment options depend on many factors and range from medical management to surgical or endovascular closure of the defect. Defects > 36 mm are typically not amenable for endovascular closure. In cases of ASD, a rim size > 3-4 mm is usually required for successful deployment and seating of the closure device, although newer devices and techniques may require less of a rim. Imaging Protocols When evaluating a patient with an intracardiac shunt, it is important to determine the location and size of the defect, identify associated abnormalities, quantify ventricular volumes and function, and calculate the Qp:Qs ratio. All of this information can be obtained with cardiac MR. Cardiac CT is an alternative used when MR is contraindicated or nondiagnostic; however, direct flow quantification (Qp:Qs) cannot be obtained with cardiac CT. Cardiac MR Cardiac MR protocol to assess for intracardiac shunts includes basic localizer images followed by single, balanced steady-state free precession (SSFP) images in the paraseptal long axis and modified four-chamber views. These images are then used to prescribe images covering the entire heart in the short-axis plane. Ideally, thin cuts without spacing should be performed in the regions of concern. These images allow for morphologic assessment of the heart, quantification of ventricular volumes and function, and detection of small dephasing jets. Additional orthogonal balanced SSFP views of the suspected jets can be obtained to confirm, if in doubt. Balanced SSFP images in the three-chamber and orthogonal (left ventricular outflow tract) planes are then performed for the purpose of prescribing phase-contrast images of the aorta. Balanced SSFP images in a right ventricular outflow tract plane and orthogonal plane “driveway” view are also performed for the purpose of prescribing phase-contrast images of the pulmonary artery. The obtained phase-contrast images are used to determine the Qp:Qs ratio using dedicated postprocessing software. Finally, three-dimensional whole-heart images may be obtained for morphologic assessment of the defect and for detection of associated anomalies. Cardiac CT Cardiac CT can be used in cases of intracardiac shunts where MR is contraindicated and echocardiography is inadequate. Cardiac CT allows the detection and sizing of the defects. Particularly, the analysis of the surrounding rim is easily performed in CT due to the high-resolution isovolumetric nature of the datasets. Furthermore, using retrospectively gated image acquisition with contrast bolus followed by 40-50 mL of salinecontrast mix (50% saline, 50% contrast), cardiac CT can be used to assess end-diastolic and end-systolic ventricular volumes and function to assess for right ventricular overload. Overall, cardiac CT has excellent spatial resolution that allows accurate sizing of the defect and visualization of the surrounding structures for the purpose of treatment. Selected References 202

Diagnostic Imaging Cardiovascular 1. Rojas CA et al: Ventricular septal defects: embryology and imaging findings. J Thorac Imaging. 28(2):W28-34, 2013 2. Rojas CA et al: Traumatic ventricular septal defect: characterization with electrocardiogram-gated cardiac computed tomography angiography. J Thorac Imaging. 27(6):W174-6, 2012 3. Johri AM et al: Imaging of atrial septal defects: echocardiography and CT correlation. Heart. 97(17):1441-53, 2011 4. Rojas CA et al: Embryology and developmental defects of the interatrial septum. AJR Am J Roentgenol. 195(5):11004, 2010 5. Jacobs JP et al: Congenital Heart Surgery Nomenclature and Database Project: atrial septal defect. Ann Thorac Surg. 69(4 Suppl):S18-24, 2000 6. Jacobs JP et al: Congenital Heart Surgery Nomenclature and Database Project: atrioventricular canal defect. Ann Thorac Surg. 69(4 Suppl):S36-43, 2000 7. Jacobs JP et al: Congenital Heart Surgery Nomenclature and Database Project: ventricular septal defect. Ann Thorac Surg. 69(4 Suppl):S25-35, 2000

Patent Ductus Arteriosus Patent Ductus Arteriosus Suhny Abbara, MD, FSCCT Christopher M. Walker, MD Key Facts Terminology  Persistent postnatal patency of normal prenatal connection from pulmonary artery to proximal descending aorta  Category: Acyanotic, increased pulmonary blood flow  PDA is frequently an essential part of complex congenital heart disease o Hypoplastic left heart syndrome, preductal coarctation, interrupted aortic arch: Conduit for systemic perfusion (R → L flow) o D-transposition: Necessary for admixture between systemic and pulmonary circuits (L → R flow) o Pulmonary atresia and other severe cyanotic heart diseases with right-sided obstruction: Conduit for pulmonary perfusion (L → R flow) Imaging  Cardiomegaly (left atrium and left ventricle)  Increased pulmonary vascularity  Enlarged proximal aortic arch Top Differential Diagnoses  Other causes of L → R shunting o Septal defects, atrioventricular canal, partial anomalous pulmonary venous return  Persistent fetal circulation syndrome Pathology  Postnatal persistence of normal prenatal ductus arteriosus beyond 3 months of life Clinical Issues  Irreversible pulmonary hypertension (Eisenmenger physiology) results in shunt reversal and development of cyanosis Diagnostic Checklist  Detailed description of PDA influences percutaneous closure technique (coils vs. occluder devices)

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(Left) Graphic shows dilated left ventricle and enlargement of the ascending aorta due to volume overload of the left heart from aortic to pulmonary arterial left-to-right shunt through a PDA . (Right) Oblique coronal MIP MRA shows a large abnormal connection between the pulmonary artery and the distal aortic arch , indicating PDA . Note the higher signal intensity (Gd) blood passing from the aorta into the pulmonary circulation.

(Left) RVOT SSFP MR shows a spin dephasing flow void artifact directed retrograde into the main pulmonary artery that was constant throughout systole and diastole due to a small PDA . (Right) RVOT SSFP MR from the same patient shows an 8 mm PDA connecting the aortic isthmus with the pulmonary arteries. Note the dilation of the right ventricle , which can be seen in adults with longstanding PDA. P.3:5

TERMINOLOGY Abbreviations  Patent ductus arteriosus (PDA) Synonyms  Persistent arterial duct, patent ductus Botalli, patent Botallo's duct Definitions  Persistent postnatal patency of normal prenatal connection from proximal left pulmonary artery (PA) to aortic isthmus  Category: Acyanotic, increased pulmonary blood flow  Hemodynamics: L → R shunt between aorta and PA  PDA is frequently an essential part of complex congenital heart disease

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Hypoplastic left heart syndrome, preductal coarctation, interrupted aortic arch: Conduit for systemic perfusion (R → L flow) o D-transposition: Necessary for admixture between systemic and pulmonary circuits (L → R flow) o Pulmonary atresia and other severe cyanotic heart diseases with right-sided obstruction: Conduit for pulmonary perfusion (L → R flow)  PDA is part of persistent fetal circulation syndrome: R → L flow o Severe lung disease (meconium aspiration, surfactant deficiency disease, neonatal pneumonia) o Primary pulmonary hypertension of neonate IMAGING General Features  Best diagnostic clue o Connection of aorta and PA near normal ductus bump o Flow jet from aorta into PA Radiographic Findings  Radiography o Cardiomegaly (left atrium and left ventricle) o Increased pulmonary vascularity and main PA enlargement o Enlarged proximal aortic arch CT Findings  CTA o Excellent for sizing of ductus prior to cardiac catheterization for placement of occluder device o 3D volume renditions of aortic arch depict PDA o May demonstrate marked dilatation of main pulmonary artery and compression of coronary arteries MR Findings  Cardiac gated T1-weighted (black blood) imaging o Sagittal oblique plane through aortic arch depicts ductus  Cine steady-state free precession (SSFP) MR for right ventricular function in cases with Eisenmenger pulmonary hypertension o May demonstrate flow jet from aorta into pulmonary artery or, if Eisenmenger physiology occurred, bidirectional jets  3D gadolinium MRA with multiplanar reformations and volume-rendered reconstructions for direct visualization and sizing  Phase contrast imaging for quantification of left to right shunt Echocardiographic Findings  Echocardiogram o Suprasternal notch view: Direct visualization of ductus  Pulsed Doppler o Diastolic flow reversal in descending and abdominal aorta (ductus steal) o Flow acceleration across ductus (transductal velocity ratio [TVR]) expresses degree of PDA constriction  TVR = peak velocity at pulmonary / peak velocity at aortic portion of PDA  Color Doppler o Flow direction through ductus o Flow into main PA from aorta through PDA Angiographic Findings  Conventional o Cardiac catheterization only needed for associated complex cyanotic heart disease and to determine reversibility of pulmonary hypertension o Placement of PDA closure device Imaging Recommendations  Protocol advice o Treatment decisions are based only on echocardiographic findings in majority of cases DIFFERENTIAL DIAGNOSIS Other Causes of L → R Shunting  Septal defects, atrioventricular canal, partial anomalous pulmonary venous return Persistent Fetal Circulation Syndrome  Pulmonary hypertension (primary or secondary to severe lung disease)  Patent foramen ovale, PDA secondary to profound irreversible hypoxia 205

Diagnostic Imaging Cardiovascular PATHOLOGY General Features  Etiology o Prematurity: Persistent postnatal hypoxia → failure of ductus constriction o Term infant: Association with maternal rubella o Syndrome: Trisomy 21, 4p, Holt-Oram, incontinentia pigmenti  Genetics o No specific genetic defect identified in most cases of isolated PDA  Normal neonate: Ductus arteriosus closes functionally 18-24 hours after birth and anatomically at 1 month  PDA is postnatal persistence of normal prenatal structure beyond 3 months of life  Embryology o Ductus originates from primitive 6th left aortic arch  Pathophysiology (for simple PDA) o L → R shunt to PA P.3:6

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Volume overload of left atrium and left ventricle with eventual decompensation and pulmonary edema o Eisenmenger physiology: Pulmonary hypertension and right ventricular pressure overload → reversal of shunt (R → L) and cyanosis (late finding) o Diastolic flow reversal in aorta can lead to renal and intestinal hypoperfusion: Renal dysfunction, necrotizing enterocolitis Staging, Grading, & Classification  Morphologic classification by angiography o Type A: Narrowest diameter at pulmonary insertion o Type B: Narrowest diameter at aortic insertion o Type C: Same diameter throughout o Type D: Multiple constrictions o Type E: Bizarre conical configuration and constriction away from PA Gross Pathologic & Surgical Features  Patent arterial duct, most often wider on aortic side o Length: 2-8 mm; diameter 4-12 mm o Makes an acute angle with aorta in simple PDA; blunt angle with associated congenital heart disease  Contractile tissue mainly on pulmonary side, spirally arranged muscle bundles in media o Prostaglandin E1 present in fetal life maintains relaxation o Increased oxygen pressure causes constriction  Thickening of intima with mucoid degeneration  Closed ductus forms ligamentum arteriosum, which often calcifies (calcification in aortopulmonary window on chest x-ray)  Can be right-sided CLINICAL ISSUES Presentation  Most common signs/symptoms o Characteristic continuous machinery-like murmur o Bounding peripheral pulses o Congestive heart failure o Special situation: Premature infant recovering from surfactant deficiency disease  Decrease in hypoxia  Drop in pulmonary vascular resistance  Increase in shunt flow through ductus arteriosus  Clinical and radiographic signs of congestive heart failure (cardiomegaly, pulmonary edema)  Other signs/symptoms o Ductal aneurysm  Can result from premature narrowing of ductus on pulmonary side Demographics  Epidemiology o 10-12% of congenital heart disease cases 206

Diagnostic Imaging Cardiovascular o 1 per 2,500-5,000 live births o Slightly more common in females o Associated with prematurity (21-35%) Natural History & Prognosis  Irreversible pulmonary hypertension (Eisenmenger physiology) → shunt reversal and development of cyanosis  Isolated PDA: Excellent prognosis with early closure  When associated with complex heart disease: Prognosis determined by underlying disorder  Persistent fetal circulation, pulmonary hypertension: Treatment with extracorporeal membrane oxygenation is often necessary to disrupt vicious circle o Hypoxia → pulmonary vasoconstriction → decreased pulmonary flow → more severe hypoxia Treatment  To close ductus in premature infants: Indomethacin (prostaglandin inhibitor) o Side effects: Renal failure, intestinal perforation, intracranial hemorrhage  To keep ductus open (cyanotic heart disease): Prostaglandin E1  Term infants, older children: Surgical clipping or ligation o Can be performed under video-assisted thorascopic &/or robotic guidance o Complications: Inadvertent ligation of aortic isthmus, PA, or recurrent laryngeal nerve  Endovascular closure with duct occluder devices &/or coils o Small ductus (< 4 mm): Gianturco coils o Large ductus (> 4 mm): Ivalon plug, Rashkind and Amplatz duct occluders o Complications: Protrusion of occluder device into left PA orifice (→ decreased left lung perfusion), peripheral embolization o Incomplete closure in 10-20% DIAGNOSTIC CHECKLIST Reporting Tips  Detailed description of PDA influences percutaneous closure technique (coils vs. occluder devices) o Length and diameter at aortic and PA ends; diameter and location of narrowest site; angle ductus makes with descending thoracic aorta; and presence of associated calcification o ± presence of complications (e.g., pulmonary hypertension) SELECTED REFERENCES 1. Kimura-Hayama ET et al: Uncommon congenital and acquired aortic diseases: role of multidetector CT angiography. Radiographics. 30(1):79-98, 2010 2. Goitein O et al: Incidental finding on MDCT of patent ductus arteriosus: use of CT and MRI to assess clinical importance. AJR Am J Roentgenol. 184(6):1924-31, 2005 3. Cannon JW et al: Application of robotics in congenital cardiac surgery. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 6:72-83, 2003 4. Hillman ND et al: Patent ductus arteriosus. In Mavroudis C et al: Pediatric Cardiac Surgery. 3rd ed. Philadelphia: Mosby. 223-33, 2003 5. Morgan-Hughes GJ et al: Morphologic assessment of patent ductus arteriosus in adults using retrospectively ECGgated multidetector CT. AJR Am J Roentgenol. 181(3):749-54, 2003 6. Wang ZJ et al: Cardiovascular shunts: MR imaging evaluation. Radiographics. 23 Spec No:S181-94, 2003 7. Anil SR et al: Coil occlusion of the small patent arterial duct without arterial access. Cardiol Young. 12(1):51-6, 2002 8. Jan SL et al: Isolated neonatal ductus arteriosus aneurysm. J Am Coll Cardiol. 39(2):342-7, 2002 P.3:7

Image Gallery

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(Left) Volume-rendered 3D MRA shows a small PDA connecting the proximal descending aorta to the proximal left main pulmonary artery. Note the enlargement of the main pulmonary artery. (Right) Axial CECT in a patient with a PDA shows the normal post-treatment CT appearance of a percutaneously placed self-expandable Nitinol wire mesh device (Amplatzer duct occluder) .

(Left) Frontal radiograph in an intubated 8-week-old baby shows a surgical clip used to ligate a PDA. The location between the aortic knob and the left pulmonary artery is typical, and so is the orientation. Diffuse increased bilateral pulmonary opacity is secondary to pulmonary edema. (Right) Frontal radiograph in a 22-year-old man shows the size of the surgical clip used to ligate the PDA during infancy.

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(Left) Frontal radiograph shows cardiomegaly and enlargement and convexity of the main pulmonary artery segment indicating presence of pulmonary arterial hypertension. Note the calcification (see also the magnified inset) immediately superior to the main pulmonary artery in the expected location of the ductus arteriosus. (Right) Axial CECT from the same patient shows a widely patent ductus arteriosus. Note the wall calcification corresponding to the chest radiograph finding . P.3:8

(Left) Coronal MRA shows a small PDA between the proximal left pulmonary artery and the proximal descending thoracic aorta. (Right) Frontal radiograph in an acyanotic infant shows increased pulmonary vascularity and mild pulmonary edema. A continuous murmur on auscultation was present, and a PDA was subsequently diagnosed.

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(Left) Oblique coronal CTA shows a predominantly left-to-right shunt with less opacified blood passing from the distal aortic arch into the pulmonary artery, but also some reverse flow. Note the wall calcification of the PDA. (Right) Axial CTA in the same patient shows marked right ventricular hypertrophy and right atrial enlargement due to pulmonary hypertension and tricuspid regurgitation from the longstanding left-to-right shunt.

(Left) Lateral catheter angiography with injection of the distal aortic arch demonstrates a large PDA with a smaller distal opening into the pulmonary artery. Note the contrast filling the main pulmonary artery . (Right) Lateral catheter angiography in the same patient after endovascular treatment shows endovascular coils within the PDA with significant reduction of flow into the main pulmonary artery. P.3:9

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(Left) Frontal radiograph shows marked enlargement of the main , right, and left pulmonary arteries indicating pulmonary arterial hypertension. There is increased vascularity throughout the lungs, which raises the possibility of a shunt. (Right) Axial CECT from the same patient shows a PDA connecting the aortic isthmus and proximal left pulmonary artery. Note the increased pulmonary vascularity in both lungs, which is characteristic of a left-to-right shunt.

(Left) Axial CECT from the same patient shows a large atrial septal defect and marked right-sided chamber enlargement with right ventricular muscular hypertrophy . (Right) Coronal Tc-MAA shunt study in the same patient shows expected uptake within bilateral lungs. Note the bilateral kidney and brain uptake indicating the presence of shunt reversal (now right to left) due to Eisenmenger physiology.

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(Left) Oblique MIP image from MRA shows a small PDA connecting the distal aortic arch and proximal left main pulmonary artery. There is a discrete hemodynamically significant postductal aortic coarctation . (Right) Volumerendered MRA from the same patient demonstrates the small PDA and the focal postductal aortic coarctation .

Atrial Septal Defects Atrial Septal Defects Carlos Rojas, MD Suhny Abbara, MD, FSCCT Brett W. Carter, MD Key Facts Terminology  Atrial septal defect (ASD)  Interatrial septum defects that allow left to right shunt Imaging  Radiography o Enlarged right ventricle and right atrium with shunt vascularity  Cardiac gated CTA o Direct visualization of ASD o Evaluation of right atrial and ventricular volumes o Associated abnormalities  MR o Direct visualization of ASD o Determination of shunt volume and direction o Evaluation of right atrial and ventricular volumes o Associated abnormalities Top Differential Diagnoses  Ventricular septal defect  Patent ductus arteriosus  Pulmonary artery hypertension Clinical Issues  Usually asymptomatic in early life  Becomes symptomatic with advancing age  90% of patients become symptomatic by 40 years o Exertional dyspnea, fatigue, palpitations, congestive heart failure  Surgical repair o Open repair with extracorporeal support most common o Minimally invasive approaches  Percutaneous transcatheter therapy 212

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Small ostium secundum defects most amenable with rim > 5 mm Fewer complications vs. surgical repair

(Left) AP chest radiograph demonstrates increased size and number of pulmonary vessels, enlargement of the left and right pulmonary arteries , and enlargement of the pulmonary trunk . These findings indicate shunt vascularity and pulmonary arterial hypertension in this patient with an ASD. (Right) Lateral radiograph demonstrates enlargement of left and right pulmonary arteries and right ventricle consistent with shunt vascularity due to volume overload in this patient with an ASD.

(Left) Four-chamber view cardiac CT demonstrates a defect in the mid interatrial septum consistent with ostium secundum ASD . There is left-to-right shunt and secondary enlargement of the right atrium and right ventricle due to chronic volume overload. (Right) Short-axis cardiac CT demonstrates a defect in the mid interatrial septum consistent with an ostium secundum ASD . Note the enlarged right ventricle and open tricuspid valve . P.3:11

TERMINOLOGY Abbreviations  Atrial septal defect (ASD) Definitions  Interatrial septum defects allow left to right shunt IMAGING General Features  Best diagnostic clue

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Enlarged right atrium (RA) and right ventricle (RV) and shunt vascularity (overcirculation) on chest radiography

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Location o Ostium primum defect (15-20%)  Anterior/inferior interatrial septum  May involve atrioventricular valves o Ostium secundum defect (75%)  Mid interatrial septum  Oval defect bordered by fossa ovalis o Sinus venosus defect (5-10%)  Superior interatrial septum near superior vena cava (SVC) or inferior interatrial septum near inferior vena cava (IVC)  Superior or inferior to fossa ovalis o Unroofed coronary sinus (< 1%)  Intact interatrial septum with physiologic communication between left and right atria  Communication between left atrium (LA) and coronary sinus Radiographic Findings  Radiography o Enlargement of RA and RV depends on size of ASD  Small defects can have normal cardiac silhouette o LA typically normal in size  Differentiates ASD from ventricular septal defect (VSD) and patent ductus arteriosus (PDA) o Shunt vascularity o Pulmonary artery hypertension (PAH)  Enlarged pulmonary trunk and pulmonary arteries  Enlarged RA and RV  Pruning of peripheral pulmonary artery branches o Pulmonary edema and pleural effusions CT Findings  Cardiac gated CTA o Direct visualization and sizing of ASD o Enlarged RA and RV o Enlarged pulmonary arteries o Associated abnormalities  Partial anomalous pulmonary venous return  Pulmonary vein draining into SVC  Usually involves right upper lobe  Strongest association with sinus venosus ASD MR Findings  Phase-contrast and cine MR o Direct visualization and sizing of ASD o Assessment of shunt volume and direction o Enlarged RA and RV o Enlarged pulmonary arteries o Associated anomalies  Partial anomalous pulmonary venous return Echocardiographic Findings  Echocardiogram o Direct visualization of ASD  2D imaging via subcostal approach o Possible visualization of mitral valve prolapse o Enlarged pulmonary trunk and RV in PAH  Color Doppler o Direct visualization of ASD Angiographic Findings  Cardiac catheterization o Performed when echocardiography is inconclusive or to evaluate associated abnormalities o Extension of catheter across defect Imaging Recommendations 214

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Best imaging tool o Cardiac gated CTA or MR to visualize defect DIFFERENTIAL DIAGNOSIS Ventricular Septal Defect  Defect in interventricular septum (perimembranous, subarterial, muscular, and inflow)  L → R intracardiac shunt  Enlarged cardiac silhouette: LA and left ventricle (LV)  Pulmonary edema  Shunt vascularity Patent Ductus Arteriosus  Persistent connection between descending thoracic aorta and proximal left pulmonary artery  L → R extracardiac shunt  Enlarged cardiac silhouette: LA and LV  Enlarged aortic arch: Distinguishes PDA from VSD  Shunt vascularity  Pulmonary edema Pulmonary Arterial Hypertension  Enlarged pulmonary trunk and central pulmonary arteries  CTA: Enlargement of pulmonary trunk > 30 mm  High-resolution CT o Precapillary etiologies: Emphysema, fibrosis, honeycomb lung o Postcapillary etiologies: Centrilobular ground-glass nodules, pulmonary edema, pleural effusions o Chronic PAH: Patchy, ground-glass opacities  Precapillary etiologies: Chronic pulmonary emboli, congenital L → R shunts, lung disease, idiopathic PAH  Postcapillary etiologies: Left heart failure and mitral stenosis Patent Foramen Ovale  Normal development of interatrial septum without fusion between septum secundum and flap of septum primum  Tunnel configuration of interatrial communication o L → R shunt directed to inferior RA o R → L shunt directed to roof of LA  Present in ≤ 1/3 of population  Considered clinically relevant in patients with cryptogenic stroke and arterial hypoxemia that may require closure P.3:12  Normal communication between LA and RA in fetal life PATHOLOGY General Features  Etiology o Congenital cardiac anomaly characterized by defects within interatrial septum o Ostium secundum  Incomplete adhesion of septum primum or septum secundum at fossa ovalis o Ostium primum  Incomplete fusion of septum primum and septum secundum with endocardial cushion o Sinus venosus  Abnormal fusion of superior or inferior right pulmonary veins with SVC or RA  Genetics o Ellis van Creveld  Skeletal dysplasia with common atrium  Autosomal recessive pattern of inheritance o Holt-Oram syndrome  ASD and upper extremity anomalies  Autosomal dominant pattern of inheritance o Trisomy 21  Associated with ostium primum and endocardial cushion defects o Other syndromes 215

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Familial ASD associated with progressive atrioventricular block  Autosomal dominant pattern of inheritance  Associated abnormalities o Mitral valve abnormalities  Double-orifice mitral valve  2% of ostium primum defects o Partial anomalous pulmonary venous return  Strongest association with sinus venosus ASD CLINICAL ISSUES Presentation  Most common signs/symptoms o Usually asymptomatic in early life  Some patients may be symptomatic  Exertional dyspnea  Fatigue  Recurrent respiratory infections  Congestive heart failure o Typically become symptomatic with advancing age  90% of patients with ASD symptomatic by age 40  Exertional dyspnea, fatigue  Palpitations  Congestive heart failure o Pulmonary arterial hypertension  Dyspnea on exertion, fatigue, syncope, chest pain o Eisenmenger syndrome  May develop in large shunts that lead to pulmonary arterial hypertension and ↑ right heart pressures  Shunt reversal: L → R becomes R → L shunt  Cyanosis, polycythemia, clubbing  Headache, fatigue, marked dyspnea Demographics  Gender o F:M = 2:1  Epidemiology o 10% of all congenital cardiac anomalies o Most common congenital cardiac anomaly in adults Natural History & Prognosis  20% close spontaneously during 1st year of life o Spontaneous closure in adulthood is unlikely  1% become symptomatic during 1st year of life o 0.1% mortality  Defects may result in PAH o May be reversible if treated early o Development of Eisenmenger syndrome  Reversal of L → R shunt  25% lifetime mortality rate if unrepaired Treatment  Medical therapy o Limited to atrial arrhythmias and volume overload  Surgical repair o Indications  Right ventricular overload  Pulmonary flow to systemic flow ratio > 1.5 if reversible pulmonary hypertension o Contraindications  Pulmonary flow to systemic flow ratio < 0.7  Severe PAH o Open repair with extracorporeal support most common  Direct closure and patch repair o Minimally invasive approaches 216

Diagnostic Imaging Cardiovascular  Types: Limited thoracotomy, hemisternotomy, submammary  No difference in morbidity and mortality  Percutaneous transcatheter therapy o Use of atrial septal occluder device for secundum ASDs o Small ostium secundum defects most amenable with rim > 5 mm o Success rates: ˜ 96% o Fewer complications and decreased hospitalization time vs. surgical repair DIAGNOSTIC CHECKLIST Consider  ASD in setting of enlarged right side chambers with normal LA and shunt vascularity on chest radiography SELECTED REFERENCES 1. Johri AM et al: Imaging of atrial septal defects: echocardiography and CT correlation. Heart. 97(17):1441-53, 2011 2. Rojas CA et al: Embryology and developmental defects of the interatrial septum. AJR Am J Roentgenol. 195(5):11004, 2010 3. Kafka H et al: Cardiac MRI and pulmonary MR angiography of sinus venosus defect and partial anomalous pulmonary venous connection in cause of right undiagnosed ventricular enlargement. AJR Am J Roentgenol. 192(1):259-66, 2009 P.3:13

Image Gallery

(Left) Four-chamber view cardiac CT demonstrates a small defect in the interatrial septum immediately posterior to the atrioventricular valves compatible with an ostium primum ASD . (Right) Short-axis cardiac CT in the same patient demonstrates a small defect in the superior and anterior interatrial septum, compatible with an ostium primum ASD . There is no enlargement of the right heart secondary to the small size of the defect.

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(Left) Four-chamber view cardiac CT demonstrates a large defect in the posterior and inferior interatrial septum at the level of the right inferior pulmonary vein insertion , indicating inferior sinus venosus ASD. (Right) Threechamber view cardiac CT shows a defect in the superior interatrial septum at the superior vena cava-right atrial junction, indicating superior sinus venosus ASD . Note the high-density contrast material in the dependent left atrium, the “fallen contrast” sign .

(Left) Axial oblique MR cine image demonstrates a large superior sinus venosus ASD with partial anomalous pulmonary venous return to the superior vena cava . Note the right inferior pulmonary vein entering the left atrium . (Right) Four-chamber view CTA of the chest demonstrates free communication between the 4 cardiac chambers at the crux of the heart , indicating endocardial cushion defect. Note the contrast shunting from the left heart into the right ventricle. P.3:14

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(Left) Three-chamber view cardiac CT demonstrates abnormal communication between the left atrium and the coronary sinus, consistent with unroofed coronary sinus ASD . (Right) Short-axis cardiac CT demonstrates abnormal communication between the left atrium and the coronary sinus, with higher attenuation of blood from the left atrium entering the coronary sinus, consistent with an unroofed coronary sinus ASD .

(Left) Short-axis cardiac CT demonstrates lack of fusion between septum secundum and the flap valve of septum primum , consistent with a patent foramen ovale (PFO) . A high-density blood column extends from the LA into the RA and terminates in a contrast jet entering the RA, indicating L → R shunt. (Right) Four-chamber view cardiac CT demonstrates the interatrial tunnel of a PFO . This is a common finding, and PFO can be called only if contrast enters the RA.

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(Left) Axial oblique PC MR magnitude images above the semilunar valves are used to quantify the flow in the main pulmonary artery and ascending aorta and the ratio of pulmonary (Qp) to systemic (Qs) flow (Qp:Qs). Qp:Qs > 1.5 is considered a significant shunt. (Right) Axial oblique PC MR velocity-encoded images above the semilunar valves are used to measure the flow in the main pulmonary artery and ascending aorta and thus quantify the Qp:Qs ratio. P.3:15

(Left) PA and lateral chest radiographs of a patient following percutaneous closure of an ASD demonstrate an atrial septal occluder projecting over the expected position of the interatrial septum. (Right) Four-chamber view cardiac CT demonstrates a normally seated, self-centering Amplatzer Septal Occluder device (AGA; Plymouth, MN) in place from endovascular closure of an ostium secundum ASD.

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(Left) Graphic shows the placement of an atrial septal occluder introduced into the right atrium via the inferior vena cava approach. The device is placed and expanded within the ASD so that its double-disc morphology secures it within the defect, resulting in closure. (Right) Coronal oblique cardiac CT shows a normally seated, self-centering CardioSEAL STARFlex Septal Occluder device (NMT Medical; Boston, MA) in place from endovascular closure of an ostium secundum ASD.

(Left) Axial oblique cardiac CT in a patient with superior sinus venosus defect after surgical repair (Warden procedure) shows high-density contrast flowing through reconstructed SVC into the RA. The abnormal venous return of the right upper lobe has been baffled back into the LA. (Right) Coronal oblique cardiac CT (same patient) shows highdensity contrast flowing through reconstructed SVC into the RA . The abnormal venous return of the right upper lobe has been baffled back into the LA.

Ventricular Septal Defects Ventricular Septal Defects Carlos Rojas, MD Suhny Abbara, MD, FSCCT Brett W. Carter, MD Key Facts Terminology  Ventricular septal defect (VSD) Imaging  Chest radiographs may be normal with small defects  Cardiac enlargement with larger defects 221

Diagnostic Imaging Cardiovascular o Left atrial enlargement: Distinguishes VSD and patent ductus arteriosus from atrial septal defect Aortic arch normal in size: Distinguishes VSD from patent ductus arteriosus Findings of pulmonary artery hypertension Direct visualization of VSD on echocardiography, CT, and MR o Echocardiography: Identifies and characterizes most VSDs o MR: Ventricular volumes and function; direction and quantification of shunt Top Differential Diagnoses  Atrial septal defect  Patent ductus arteriosus  Pulmonary artery hypertension Pathology  Congenital are most common  4 types depending on location of defect: Perimembranous, subarterial, muscular, and inlet Clinical Issues  Patients with small defects may be asymptomatic  Small VSDs typically close spontaneously  Large VSDs require surgical correction  Defects may result in pulmonary artery hypertension and Eisenmenger syndrome  Treatment can be medical or surgical   

(Left) AP radiograph of the chest demonstrates severe enlargement of the main and central pulmonary arteries, most conspicuous on the right . (Right) Axial oblique cardiac CT in the same patient demonstrates massive enlargement of the pulmonary trunk and main pulmonary arteries with arterialization of the walls secondary to pulmonary arterial hypertension from intracardiac shunt.

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Diagnostic Imaging Cardiovascular (Left) Axial oblique cardiac CT in the same patient demonstrates a large subarterial ventricular septal defect associated with right ventricular muscular hypertrophy and massive enlargement of the pulmonary arteries . Note that there is no enlargement of the cardiac chambers. (Right) Axial image from a cardiac gated CTA demonstrates a perimembranous ventricular septal defect . P.3:17

TERMINOLOGY Abbreviations  Ventricular septal defect (VSD) IMAGING General Features  Best diagnostic clue o Enlargement of right ventricle, pulmonary vasculature, left atrium, and left ventricle on chest radiography  Location o Perimembranous (75%) o Inlet (8-10%) o Muscular (5-10%) o Subarterial (5%)  Morphology o Multiple defects may occur  More common in muscular septum (“Swiss cheese” VSD) Radiographic Findings  Radiography o Chest radiographs may be normal in patients with small defects o Medium-sized defects  Mild enlargement of cardiac silhouette  Enlarged pulmonary vasculature in setting of pulmonary hypertension o Large defects  Enlargement of cardiac silhouette  Left atrial enlargement: Distinguishes VSD and patent ductus arteriosus (PDA) from atrial septal defect (ASD)  Aortic arch normal in size: Distinguishes VSD from PDA  Enlarged pulmonary vasculature  Pulmonary edema and pleural effusions may be present CT Findings  Cardiac gated CTA o Direct visualization of VSD o Determination of location and direction of shunting MR Findings  Phase-contrast and cine MR o Ventricular volume, mass, function o Shunt volume and direction o Valvular function Echocardiographic Findings  Echocardiogram o Most VSDs are identified and sufficiently characterized by echocardiography o Direct visualization of defects and direction and velocity of shunting on Doppler/duplex sonography o Perimembranous defects are best seen on parasternal short axis at 11-o'clock position o Subarterial defects are best seen on parasternal short axis at 1-o'clock position  Color Doppler o Helpful in detecting small defects Angiographic Findings  Small defects o Normal right heart pressures o Normal pulmonary vascular resistance  Large defects o Pulmonary flow > systemic flow (Qp:Qs > 1) 223

Diagnostic Imaging Cardiovascular o Pulmonary and systemic systolic pressures equivalent Eisenmenger syndrome o Elevated systolic and diastolic pulmonary artery pressures o Desaturation of blood in left ventricle o Minimal left-to-right shunting Imaging Recommendations  Best imaging tool o Cardiac gated CTA or MR to visualize defect DIFFERENTIAL DIAGNOSIS Atrial Septal Defect  Left-to-right shunt  Left atrium typically normal in size: Distinguishes ASD from VSD  Enlargement of right ventricle  Enlarged pulmonary vasculature  Pulmonary edema Patent Ductus Arteriosus  Persistent connection between descending thoracic aorta and proximal left pulmonary artery  Left-to-right shunt  Enlargement of cardiac silhouette (left atrium and left ventricle)  Enlargement of aortic arch: Distinguishes PDA from VSD  Enlarged pulmonary vasculature  Pulmonary edema Pulmonary Artery Hypertension  Enlarged pulmonary trunk and central pulmonary arteries  CTA: Enlargement of pulmonary trunk > 30 mm  High-resolution CT o Precapillary etiologies: Emphysema, fibrosis, honeycomb lung o Postcapillary etiologies: Centrilobular ground-glass nodules, pulmonary edema, pleural effusions o Chronic PAH: Patchy ground-glass opacity  Precapillary etiologies: Chronic pulmonary emboli, congenital left-to-right shunts, lung disease, idiopathic PAH  Postcapillary etiologies: Left heart failure and mitral stenosis PATHOLOGY General Features  Etiology o Congenital: Most common etiology o Traumatic: Blunt or penetrating chest trauma o Postmyocardial infarction o Endocarditis  Associated abnormalities P.3:18 

o Tetralogy of Fallot, truncus arteriosus, and double-outlet right ventricle o Coarctation and tricuspid atresia less common Staging, Grading, & Classification  4 types depending on location of defect  Perimembranous o Below crista supraventricularis and anterior to septal leaflet of tricuspid valve o Bound by both membranous and muscular tissue o Can be associated to misalignment of aortopulmonary septum (tetralogy of Fallot and interrupted aortic arch) o 1/3 close spontaneously by apposition of septal leaflet of tricuspid valve o Gerbode defect (left ventricle to right atrium communication) is located at atrioventricular membranous septum  Muscular o Located in trabecular portion of interventricular septum o Bound by muscle 224

Diagnostic Imaging Cardiovascular o 2/3 located in apical region Subarterial o Below semilunar valve and above crista supraventricularis o Bound by fibrous annulus of semilunar valves &/or muscular tissue o Associated with aortic vale prolapse and regurgitation  Inflow o Associated with endocardial cushion defects o Associated with trisomy 18 and trisomy 21 o Bound by tricuspid valve annulus o Extends to muscular septum ± membranous septum CLINICAL ISSUES Presentation  Most common signs/symptoms o Patients with small defects may be asymptomatic  “Maladie de Roger”  Small, asymptomatic VSD o Development of symptoms depends on several factors  Size and location  Pulmonary arterial pressure  Left ventricular outflow resistance o Most common symptoms  Shortness of breath, tachypnea, tachycardia, and failure to thrive o Pulmonary artery hypertension  Dyspnea on exertion, fatigue, syncope, and chest pain o Eisenmenger syndrome  Symptoms related to polycythemia  Headache, fatigue, and marked dyspnea o Physical examination  Holosystolic or pansystolic murmur  Other signs/symptoms o Recurrent respiratory infections Demographics  Gender o M:F = 1:1  Epidemiology o VSD accounts for 20% of all congenital cardiac anomalies o Incidence: 2-6 of every 1,000 live births Natural History & Prognosis  Defects that spontaneously close or decrease in size early in life usually require no treatment  Small VSDs typically close spontaneously o Inlet VSDs rarely close spontaneously  Large VSDs require surgical correction  Defects may result in pulmonary artery hypertension o May be reversible if treated early o Development of Eisenmenger syndrome  Reversal of left-to-right shunt Treatment  Medical management o Treatment of congestive heart failure  Diuretics and afterload reduction o Treatment of Eisenmenger syndrome  Partial exchange transfusion o Endocarditis prophylaxis  Surgical management o Pulmonary artery banding  May enable postponement of surgery  Constriction of VSD may be seen o Surgical closure  Indications 

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Diagnostic Imaging Cardiovascular  Symptomatic patients  Large defects  Elevated pulmonary vascular resistance o Minimally invasive surgical closure  Typically for perimembranous VSD o Percutaneous transcatheter device occlusion  Typically for perimembranous and muscular VSDs  Complications  Complete heart block  Aortic regurgitation  Tricuspid regurgitation DIAGNOSTIC CHECKLIST Consider  VSD in patient with left atrial and ventricular enlargement and prominent pulmonary vasculature on chest radiography Image Interpretation Pearls  Right cardiac enlargement is less common than with ASDs SELECTED REFERENCES 1. Rojas CA et al: Ventricular septal defects: embryology and imaging findings. J Thorac Imaging. 28(2):W28-34, 2013 2. Wang ZJ et al: Cardiovascular shunts: MR imaging evaluation. Radiographics. 23 Spec No:S181-94, 2003 3. Jacobs JP et al: Congenital Heart Surgery Nomenclature and Database Project: ventricular septal defect. Ann Thorac Surg. 69(4 Suppl):S25-35, 2000 P.3:19

Image Gallery

(Left) Coronal oblique MR (3D bSSFP) demonstrates a moderately sized subarterial ventricular septal defect in this patient with tetralogy of Fallot. Also note right ventricular hypertrophy . (Right) Axial oblique MR (3D bSSFP) demonstrates a moderately sized subarterial ventricular septal defect . Note that the enlargement of the right ventricle is only mild.

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(Left) Four-chamber view MR cine single image during systole demonstrates a large apical muscular ventricular septal defect associated with coarse trabeculations in the mid right ventricle. (Right) Three-chamber view MR cine single image in the same patient during systole shows a large, apical muscular ventricular septal defect associated with coarse trabeculations in the mid right ventricle and small intrachamber jet compatible with a dualchamber right ventricle.

(Left) Short-axis cardiac CT in a patient with history of blunt trauma shows a large defect in the basal anterosuperior wall of the left ventricle extending to the right ventricular outflow tract (RVOT) , compatible with a traumatic ventricular septal defect . (Right) Three-chamber view cardiac CT demonstrates a large defect in the anterosuperior wall of the left ventricle extending to the RVOT , compatible with a traumatic ventricular septal defect . P.3:20

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(Left) Sagittal reformatted image from a cardiac gated CTA shows a small subarterial (supracristal) ventricular septal defect . Ventricular septal defects account for approximately 20% of congenital cardiac anomalies. (Right) Axial cardiac gated CTA demonstrates a defect within the high aspect of the interventricular septum near the noncoronary cusp of the aorta, allowing for flow communication between the left and right ventricles.

(Left) Axial oblique PC MR (magnitude) image of the pulmonary artery is routinely performed to assess the pulmonary flow and compare it to the systemic flow to quantify the degree of shunting. (Right) Axial oblique PC MR (velocity) image of the pulmonary artery is routinely performed to assess the pulmonary flow and compare it to the systemic flow to quantify the degree of shunting.

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(Left) Axial oblique PC MR (magnitude) image of aorta is routinely performed to assess the systemic flow and compare it to the pulmonary flow to quantify the degree of shunting. (Right) Axial oblique PC MR (velocity) image of the aorta is routinely performed to assess the systemic flow and compare it to the pulmonary flow to quantify the degree of shunting. P.3:21

(Left) Axial oblique cardiac CT demonstrates a small aneurysm of the interventricular septum secondary to spontaneous closure of perimembranous VSD. No residual shunting was noted. (Right) Portable chest radiograph obtained following percutaneous device closure of a VSD shows an occluder device in the expected position of the interventricular septum. Note is made of the sternotomy wires in this patient with a previous aortic valve replacement .

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(Left) Four-chamber view cardiac CT in patient with history of D-transposition of the great vessels and perimembranous VSD repair shows a small outpouching of contrast in the region of the perimembranous septum , consistent with postsurgical change. (Right) Short-axis cardiac CT (same patient) shows a small outpouching of contrast below the crista supraventricularis , consistent with postsurgical change from prior perimembranous VSD repair. No residual shunting was noted.

(Left) Axial CT image in a patient with history of tetralogy of Fallot demonstrates high-density material in the region of the LVOT and interventricular septum from prior patch repair of a large subarterial VSD. (Right) Short-axis cardiac CT in the same patient demonstrates high-density material in the region of the LVOT and interventricular septum from prior patch repair of a large subarterial VSD. Metallic artifact from ICD wire is noted in the right ventricle.

Endocardial Cushion Defect Endocardial Cushion Defect Carlos Rojas, MD Suhny Abbara, MD, FSCCT Key Facts Terminology  Synonyms: Atrioventricular (AV) septal defect; atrioventricular canal (AVC) defect  Broad spectrum of defects characterized by involvement in atrial septum, ventricular septum, and AV valves Imaging  Echocardiography o Defines lesion in infants and young children 230

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MR

o Direct visualization of defects o Evaluation of chamber size and function o Shunt direction and quantification Top Differential Diagnoses  Atrial septal defect (ASD)  Ventricular septal defect (VSD)  Patent ductus arteriosus  Gerbode defect Pathology  Partial AVC: Ostium primum ASD + varying degrees of left AV valve malformation  Intermediate AVC: Ostium primum ASD + inflow VSD (restrictive) + left AV valve malformation + right AV valve malformation  Complete AVC: Ostium primum ASD + inflow VSD (nonrestrictive) + common AV valve Clinical Issues  Large AVC defects present early in life with tachypnea, tachycardia, failure to thrive  Small partial AVC defect can be asymptomatic early in life  Medical management of congestive heart failure  Surgical closure of atrial- and ventricular-level defects o Surgical correction of AV valve clefts

(Left) AP radiograph in a patient with Down syndrome and known complete atrioventricular canal shows an enlarged cardiac silhouette and increased pulmonary vascularity. Note that only 11 sets of ribs are present. (Right) Fourchamber single MR cine image demonstrates global cardiomegaly in a patient with a complete AVC. Note a single common AV valve and open communication between the right atrium (RA), left atrium (LA), right ventricle (RV), and left ventricle (LV).

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(Left) Double oblique single MR cine image through the valve plane in a patient with complete AVC demonstrates a single common AV valve. Note anterior leaflet . AV = aortic valve; PA = pulmonary artery. (Right) Short-axis PC MR velocity-encoded image at the level of the atria demonstrates black signal at the site of common AV valve (incomplete) coaptation during systole, indicative of AV valve regurgitation . P.3:23

TERMINOLOGY Abbreviations  Endocardial cushion defect (ECD) Synonyms  Atrioventricular (AV) septal defect  Atrioventricular canal (AVC) defect Definitions  Broad spectrum of defects characterized by involvement in atrial septum, ventricular septum, and AV valves IMAGING General Features  Best diagnostic clue o Spectrum of intracardiac shunting ranging between interatrial communication (ostium primum defect) with mitral valve cleft to a single AV valve with atrial septal defect (ASD) and unrestricted ventricular septal defect (VSD) o Associated chamber and pulmonary arterial enlargement depending on degree of shunting  Location o Partial AVC  Defect in anterior inferior aspect of atrial septum  Coexists with cleft in anterior leaflet of mitral valve  5-leaflet AV valve is present with separate valve orifices to right and left ventricles o Intermediate AVC  Defect in anterior inferior aspect of atrial septum  Small defect (restrictive) in ventricular septum immediately anterior to AV valve  Coexists with cleft in mitral and tricuspid leaflets o Complete AVC  Large defect in anterior inferior part of atrial septum  Large defect (unrestricted) in ventricular septum immediately anterior to AV valve  Common atrioventricular valve: If valve opens toward 1 ventricle, hypoplasia of 1 ventricle can be present Radiographic Findings  Chest radiograph o Large heart with shunt vascularity o When mitral insufficiency is severe, left atrium can be large and cause left lower lobe to collapse Echocardiographic Findings 232

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Echocardiogram o Echocardiography in infants and young children defines lesion  Primum defects have echo dropout in lower portion of septum, cleft in mitral valve  Anterior and superior displacement of aorta, with elongation and narrowing of left ventricular outflow tract (LVOT)  Color Doppler o Demonstration of left-to-right shunt, severity of mitral regurgitation, tricuspid regurgitation  LVOT obstruction can be quantified MR Findings  Phase-contrast and cine MR o Location, number, and size of defects o Enlargement of pulmonary vasculature o Associated mitral or tricuspid insufficiency o Atrial and ventricular volumes and function o Shunt volume and direction o Postoperative evaluation to determine residual shunting &/or valvular insufficiency CT Findings  Cardiac gated CTA o Not done for diagnosis, but identifies ASD and VSD and can quantify ventricular volumes and function o Surgical changes of AVC repair can be seen as high-density surgical material (patch) in anteriorinferior aspect of atrial septum, membranous portion of interventricular septum, &/or along AV valves Angiographic Findings  Conventional o Cardiac catheterization is not usually done to characterize anatomy but to measure pulmonary vascular resistance  Left ventriculogram shows cleft in mitral valve, shunts, respective size of ventricles, and also LVOT obstruction o “Gooseneck” deformity  Apical displacement of AV valves  Distance between mitral valve annulus and left ventricle apex > aortic valve annulus to left ventricle apex  Anteriorly located and narrow LVOT Imaging Recommendations  Best imaging tool o Echocardiography easily accessible and more commonly used to define these lesions o MR role is growing due to precise and reproducible quantification of chamber volume and function as well as quantification of shunting DIFFERENTIAL DIAGNOSIS Ventricular Septal Defect  Most common congenital heart disease (CHD) with left-to-right shunt  Most common CHD associated with other lesions  Cardiac enlargement with increased pulmonary flow Atrial Septal Defect  Defect is in atrial septum  Small defects can present later in life Patent Ductus Arteriosus  Communication between high-pressure aorta and lower-pressure pulmonary artery  Left-to-right shunt usually presents in infancy Gerbode Defect  VSD just below (apical) mitral but above tricuspid valve leaflet insertion resulting in high-gradient shunt from left ventricle into right atrium  Normal tricuspid valve annulus is apical in location in relation to mitral valve annulus, resulting in short segment of septum where there is left ventricle on 1 side and right atrium on the other P.3:24

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Diagnostic Imaging Cardiovascular PATHOLOGY General Features  Etiology o Malformation occurring during 5th week of gestation o Abnormal or inadequate fusion of superior and inferior endocardial cushions o Abnormal fusion of ventricular (trabecular) portion of septum  Genetics o Associated with trisomy 21 in 44-48%  Associated abnormalities o Children with trisomy 21 have constellation of clinical and radiographic findings  Chest radiograph may show 11 ribs, double manubrial ossification center in 80%  Many skeletal malformations, spectrum of retardation Staging, Grading, & Classification  Partial AVC (ostium primum ASD + varying degrees of left atrioventricular valve [LAVV] malformation)  Intermediate AVC (ostium primum ASD + inflow VSD [restrictive] + LAVV malformation + right atrioventricular valve malformation)  Complete AVC (ostium primum ASD + inflow VSD [nonrestrictive] + common AV valve) o Rastelli classification: Based on morphology of superior (anterior) bridging leaflet  Type A: Superior (anterior) leaflet split in 2 at septum  Type B (rare): Partially split superior (anterior) leaflet to right of septum  Left leaflet > right leaflet  Anomalous right side papillary muscle attachment to left superior (anterior) leaflet  Type C: Superior (anterior) leaflet is not divided and has no chordal attachments to ventricular septum o Unbalanced canal defect is present when AV valve opens toward 1 ventricle  Unbalanced canal defect refers to hypoplasia of 1 ventricle, resulting resulting in singleventricle physiology  Hypoplasia of inlet and outlet septa results in hypoplasia of chamber with malalignment of ventricular septum CLINICAL ISSUES Presentation  Most common signs/symptoms o Complete AVC  Presents early with tachypnea, tachycardia, and failure to thrive  Mitral insufficiency adds complexity and earlier symptoms o Partial AVC  Small shunts are well-tolerated through 1st decade, and children may be asymptomatic  Mitral insufficiency adds complexity and earlier symptoms  Other signs/symptoms o Pathophysiology of lesions  Degree of left-to-right shunting is determined by size of defect and relative compliance of atria and ventricles  Infants have high pulmonary vascular resistance and therefore rarely have shunts  As pulmonary vascular resistance decreases, left-to-right shunting increases with age  Subsequent enlargement of right atrium, right ventricular enlargement, and increase in pulmonary vascularity  Degree of regurgitation through mitral valve cleft depends on its size Demographics  Age o Infants and children  Gender o M=F  Epidemiology o 4-8 in 1,000 live births have congenital heart defects o 5-8% have AVSD Natural History & Prognosis  Complete AVC presents in infancy with symptoms  Children assessed for surgical repair o Postoperative course may be complicated by mitral insufficiency 234

Diagnostic Imaging Cardiovascular o Pulmonary hypertension occurs in unoperated children Treatment  Medical management until surgery depending on lesion and severity  Surgical management o Partial AVC  Closed by pericardial patch via right atrial approach  Percutaneous closure devices not usually done as inferior attachment may injure AV valves o Complete AVC (3% mortality)  Elective repair in children 2-5 years unless mitral regurgitation is present  Complications include mitral insufficiency, which may require reoperation, valvuloplasty, or replacement  Arrhythmias, such as sinus node dysfunction or heart block  Single-ventricle physiology: Staged single-ventricle repair (Glenn, followed by Fontan) SELECTED REFERENCES 1. Oyama N et al: 64-Slice MDCT imaging of endocardial cushion defect associated with other cardiac and extracardiac abnormalities. J Cardiovasc Comput Tomogr. 4(3):218-20, 2010 2. Rojas CA et al: Embryology and developmental defects of the interatrial septum. AJR Am J Roentgenol. 195(5):11004, 2010 3. Ferguson EC et al: Classic imaging signs of congenital cardiovascular abnormalities. Radiographics. 27(5):1323-34, 2007 4. Colletti PM: Evaluation of intracardiac shunts with cardiac magnetic resonance. Curr Cardiol Rep. 7(1):52-8, 2005 5. Beerbaum P et al: Atrial septal defects in pediatric patients: noninvasive sizing with cardiovascular MR imaging. Radiology. 228(2):361-9, 2003 P.3:25

Image Gallery

(Left) Axial CECT demonstrates large atrial septal defect and ventricular septal defect in this patient with a complete AVC. Note enlargement of the right-sided cardiac chambers . (Right) Four-chamber image from a cardiac CT shows a common atrium , muscular ventricular septal defect , and single atrioventricular valve compatible with complete AVC.

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(Left) Four-chamber view from a cardiac CT demonstrates an intermediate AVC with small ostium primum atrial septal defect and small restrictive inlet VSD . (Right) Four-chamber view cardiac CT demonstrates surgical changes from intermediate AVC surgical repair with patch closure of ostium primum atrial septal defect and repair of anterior mitral valve leaflet cleft . Note residual small inlet VSD .

(Left) Double oblique cardiac CT in a mitral valve short-axis plane demonstrates calcifications due to prior surgical repair of a cleft in the anterior mitral valve leaflet . (Right) Axial image from a cardiac CT demonstrates an unbalanced complete AVC, with a common atrium, common single atrioventricular valve , and hypoplastic right ventricle . Note unopacified lateral tunnel Fontan conduit .

Scimitar Syndrome Scimitar Syndrome Jonathan Hero Chung, MD Key Facts Terminology  Specific subtype of partial anomalous pulmonary venous return  Synonyms: Hypogenetic lung/pulmonary venolobar syndrome Imaging  Scimitar vein = curved anomalous venous trunk resembling Turkish sword, located in right medial costophrenic sulcus near right heart border  Right lung hypoplasia  Dextroversion of heart, no dextrocardia: Apex is still directed toward left  CT or MR is best at showing typical drainage of scimitar vein into inferior vena cava 236

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CT angiography with 3D reconstruction most helpful in showing anomalous systemic arterial supply and right pulmonary and mainstem bronchus hypoplasia  Phase-contrast MR for shunt flow calculation Top Differential Diagnoses  Partial anomalous pulmonary venous return  True dextrocardia with abdominal situs solitus  Isolated right pulmonary hypoplasia  Intralobar sequestration Clinical Issues  Prognosis depends on age at presentation and size of shunt o Older age of presentation, usually milder disease course o Large shunt: Development of irreversible pulmonary hypertension  Treatment o Embolization of systemic arterial supply o Baffling of common right pulmonary vein onto left atrium o Surgical repair when left-to-right shunt > 2:1

(Left) Frontal radiograph shows rightward cardiac shift from right lung hypoplasia. Also present is a curvilinear right retrocardiac opacity that curves toward the junction of the right atrium and inferior vena cava. (Right) Axial NECT shows an abnormal draining vein that eventually drains into the inferior vena cava. Rightward mediastinal shift and rotation from hypoplasia of the right lung are also present, typical of patients with scimitar syndrome.

(Left) Coronal MRA image demonstrates a large abnormal pulmonary vein draining into the inferior vena cava, consistent with partial anomalous pulmonary venous return. (Right) Catheter arteriography in a patient with scimitar syndrome, with contrast injected via pigtail catheter within the descending thoracic aorta, shows systemic arterial 237

Diagnostic Imaging Cardiovascular supply P.3:27

of the medial basal segment of the right lower lobe.

TERMINOLOGY Synonyms  Hypogenetic lung/pulmonary venolobar syndrome Definitions  Right lung hypoplasia with anomalous right pulmonary venous connection to inferior vena cava  Often associated: Anomalous systemic arterial supply  Category: Acyanotic, right-sided cardiac chamber enlargement, increased pulmonary vascularity (partial anomalous pulmonary venous return)  Hemodynamics: Venous flow from right lung returns to right atrium or inferior vena cava → volume overload of right heart (atrial septal defect [ASD] equivalent) IMAGING General Features  Best diagnostic clue o Scimitar vein = curved anomalous venous trunk resembling Turkish sword  Located in right medial costophrenic sulcus near right heart border  Increases in caliber in caudal direction Radiographic Findings  Radiography o Right lung hypoplasia o Dextroversion of heart, not dextrocardia: Apex is still directed toward left o Prominent right atrium, shunt vascularity o Scimitar vein in right medial costophrenic sulcus Fluoroscopic Findings  Normal excursions of both hemidiaphragms  No air trapping CT Findings  Axial images: Show scimitar vein joining inferior vena cava  CT angiography with 3D reconstruction: Best demonstrates anomalous systemic arterial supply and right pulmonary and mainstem bronchus hypoplasia MR Findings  Cardiac gated T1WI: Anomalous pulmonary venous connection is best seen in axial and coronal planes  Phase-contrast MRA: Enables shunt flow calculation (QP/QS ratio)  Gadolinium-enhanced MRA, coronal acquisition with 3D reconstruction: Detects anomalous right pulmonary venous and arterial development Echocardiographic Findings  Echocardiogram o No right pulmonary veins entering left atrium o Scimitar vein connecting to inferior vena cava Angiographic Findings  Conventional angiography o Scimitar vein opacifies during venous phase of pulmonary artery injection o Injection of abdominal aorta: Anomalous systemic arterial supply to right lung base (originating from celiac axis, right phrenic artery, descending aorta)  Road map for embolization of systemic artery Imaging Recommendations  CTA or MRA are better than echocardiography for complete assessment and can replace diagnostic angiocardiography  Angiography is reserved for coil embolization DIFFERENTIAL DIAGNOSIS Other Forms of Partial Anomalous Pulmonary Venous Return  Right pulmonary vein(s) to azygous vein, superior vena cava, right atrium (with sinus venosus ASD) True Dextrocardia With Abdominal Situs Solitus  Other complex cardiac anomalies Isolated Right Pulmonary Hypoplasia 238

Diagnostic Imaging Cardiovascular  Normal right pulmonary venous connection to left atrium Intralobar Sequestration  Mass in right lung base is not connected to bronchial tree with systemic arterial supply and venous drainage to pulmonary (intralobar) or systemic (extralobar) veins PATHOLOGY General Features  Genetics o No specific genetic defect is identified  Associated abnormalities o Major  Absence of right pulmonary artery  Accessory diaphragm (duplication of diaphragm)  Absence or interruption of inferior vena cava o Minor  Bilateral left-sided bronchial branching, diaphragmatic eventration, or (partial) absence  Phrenic cyst  Horseshoe lung (lung segment crossing over midline in posterior mediastinum)  Esophageal or gastric lung  Anomalous superior vena cava  Absent left pericardium o 25% are associated with other anomalies  Sinus venosus ASD (most common)  Ventricular septal defect, tetralogy of Fallot, patent ductus arteriosus  Embryology o Primary abnormality in development of right lung, with secondary anomalous pulmonary venous connection  Pathophysiology o Obligatory left-to-right (L-R) shunt to right atrium: ASD physiology Gross Pathologic & Surgical Features  Right lung (including pulmonary artery and bronchus) hypoplasia or agenesis o Most commonly affects right upper or middle lobes  Systemic arterialization of right lung base (without sequestration) P.3:28 

Anomalous right pulmonary venous drainage to inferior vena cava (most frequent) or right atrium, superior vena cava, azygos vein, portal vein, hepatic vein Microscopic Features  Normal parenchyma in right lung base (as opposed to sequestration)  Systemic artery branches anastomose with right pulmonary artery vascular bed in right lung base  Longstanding shunt: Pulmonary vascular disease leading to irreversible pulmonary hypertension (Eisenmenger physiology) CLINICAL ISSUES Presentation  Most common signs/symptoms o Depend on age at presentation and size of L-R shunt  Newborn: Congestive heart failure, right heart volume overload, pulmonary hypertension  Young child: Recurrent infections in right lung base  Older child and adult: Often asymptomatic (incidental finding on chest radiograph) Natural History & Prognosis  Large shunt: Development of irreversible pulmonary hypertension  Moderate to poor prognosis with neonatal presentation  May be asymptomatic for many years with small shunt Treatment  Embolization of systemic arterial supply  Baffling of common right pulmonary vein onto left atrium  Surgical repair is indicated when L-R shunt > 2:1 DIAGNOSTIC CHECKLIST 239

Diagnostic Imaging Cardiovascular Consider  Preoperative identification of systemic arterial supply followed by embolization is important to avoid bleeding complications Image Interpretation Pearls  Recognize anomalous vessel in medial costophrenic sulcus o Runs perpendicular to expected course of right inferior pulmonary vein o Increases in caliber in caudal direction (as opposed to normal pulmonary vein) SELECTED REFERENCES 1. Wasilewska E et al: Unilateral hyperlucent lung in children. AJR Am J Roentgenol. 198(5):W400-14, 2012 2. Korkmaz AA et al: Scimitar syndrome: a complex form of anomalous pulmonary venous return. J Card Surg. 26(5):529-34, 2011 3. Biyyam DR et al: Congenital lung abnormalities: embryologic features, prenatal diagnosis, and postnatal radiologicpathologic correlation. Radiographics. 30(6):1721-38, 2010 4. Ho ML et al: MDCT of partial anomalous pulmonary venous return (PAPVR) in adults. J Thorac Imaging. 24(2):89-95, 2009 5. Navas Lobato MA et al: Scimitar syndrome. Clin Cardiol. 32(7):E15-6, 2009 6. Gavazzi E et al: Scimitar syndrome: comprehensive, noninvasive assessment with cardiovascular magnetic resonance imaging. Circulation. 118(3):e63-4, 2008 7. Tjang YS et al: Scimitar syndrome presenting in adults. J Card Surg. 23(1):71-2, 2008 8. Wang CC et al: Scimitar syndrome: incidence, treatment, and prognosis. Eur J Pediatr. 167(2):155-60, 2008 9. Tsitouridis I et al: Scimitar syndrome versus meandering pulmonary vein: evaluation with three-dimensional computed tomography. Acta Radiol. 47(9):927-32, 2006 10. Yoo SJ et al: The relationship between scimitar syndrome, so-called scimitar variant, meandering right pulmonary vein, horseshoe lung and pulmonary arterial sling. Cardiol Young. 16(3):300-4, 2006 11. Khan MA et al: Usefulness of magnetic resonance angiography for diagnosis of scimitar syndrome in early infancy. Am J Cardiol. 96(9):1313-6, 2005 12. Berrocal T et al: Congenital anomalies of the tracheobronchial tree, lung, and mediastinum: embryology, radiology, and pathology. Radiographics. 24(1):e17, 2004 13. Sinha R et al: Scimitar syndrome: imaging by magnetic resonance angiography and Doppler echocardiography. Indian J Chest Dis Allied Sci. 46(4):283-6, 2004 14. Konen E et al: Congenital pulmonary venolobar syndrome: spectrum of helical CT findings with emphasis on computerized reformatting. Radiographics. 23(5):1175-84, 2003 15. Kramer U et al: Scimitar syndrome: morphological diagnosis and assessment of hemodynamic significance by magnetic resonance imaging. Eur Radiol. 13 Suppl 4:L147-50, 2003 16. Marco de Lucas E et al: Scimitar syndrome: complete anatomical and functional diagnosis with gadoliniumenhanced and velocity-encoded cine MRI. Pediatr Radiol. 33(10):716-8, 2003 17. Vanderheyden M et al: Partial anomalous pulmonary venous connection or scimitar syndrome. Heart. 89(7):761, 2003 18. Reddy R et al: Scimitar syndrome: a rare cause of haemoptysis. Eur J Cardiothorac Surg. 22(5):821, 2002 19. Vaes MF et al: Scimitar syndrome. JBR-BTR. 85(3):160-1, 2002 20. Zylak CJ et al: Developmental lung anomalies in the adult: radiologic-pathologic correlation. Radiographics. 22 Spec No:S25-43, 2002 21. Do KH et al: Systemic arterial supply to the lungs in adults: spiral CT findings. Radiographics. 21(2):387-402, 2001 22. Gilkeson RC et al: Gadolinium-enhanced magnetic resonance angiography in scimitar syndrome: diagnosis and postoperative evaluation. Tex Heart Inst J. 27(3):309-11, 2000 23. Huddleston CB et al: Scimitar syndrome presenting in infancy. Ann Thorac Surg. 67(1):154-9; discussion 160, 1999 24. Henk CB et al: Scimitar syndrome: MR assessment of hemodynamic significance. J Comput Assist Tomogr. 21(4):628-30, 1997 25. Baran R et al: Scimitar syndrome: confirmation of diagnosis by a noninvasive technique (MRI). Eur Radiol. 6(1):924, 1996 26. Vrachliotis TG et al: Hypogenetic lung syndrome: functional and anatomic evaluation with magnetic resonance imaging and magnetic resonance angiography. J Magn Reson Imaging. 6(5):798-800, 1996 27. Boothroyd AE et al: Shoe, scimitar or sequestration: a shifting spectrum. Pediatr Radiol. 25(8):652-3, 1995 28. Woodring JH et al: Congenital pulmonary venolobar syndrome revisited. Radiographics. 14(2):349-69, 1994 29. Figa FH et al: Horseshoe lung—a case report with unusual bronchial and pleural anomalies and a proposed new classification. Pediatr Radiol. 23(1):44-7, 1993 P.3:29

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(Left) Axial image from SSFP sequence of a cardiac MR shows an anomalous pulmonary vein draining into the inferior vena cava . There is right-sided mediastinal shift, but situs solitus. Note low volume of right lung. (Right) Coronal multiplanar reformat in the same patient shows the anomalous pulmonary vein draining into the inferior vena cava . No right-sided pulmonary veins are seen draining into the left atrium . Findings are indicative for scimitar syndrome.

(Left) Sagittal MR shows a tortuous anomalous vein in the right lower lobe representing partial anomalous pulmonary venous return in the setting of scimitar syndrome. (Right) Coronal thick minimum-intensity projection shows bilateral left-sided branching of the mainstem bronchi (note expected location of right upper lobe bronchus ), which is common in patients with scimitar syndrome. Other associations include atrial septal defects, horseshoe lung, and duplicated diaphragm.

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(Left) Frontal radiograph of the chest shows low right lung volume and rightward mediastinal shift. A tubular density is seen in the right mid and lower chest. (Right) MIP image from contrast-enhanced chest MRA shows an anomalous pulmonary venous return from the right mid and lower lung draining into the inferior vena cava. Anomalous arterial supply to the right lower lobe is also seen arising from the abdominal aorta. The rightward deviation of the heart is from the hypoplastic right lung.

Total Anomalous Pulmonary Venous Return Total Anomalous Pulmonary Venous Return Jonathan Hero Chung, MD Key Facts Terminology  Total anomalous pulmonary venous return (TAPVR)  Embryologic failure of common pulmonary vein to connect to left atrium Imaging  Chest radiograph: Nonspecific appearance  CT o Thickened interlobular septa, peribronchial cuffing, and ground-glass opacity suggest postoperative anastomotic pulmonary venous stenosis o 3D CT angiography: For pre- and postoperative pulmonary vein caliber measurements  MR o Gadolinium-enhanced MRA: Allows for multiplanar reformations and volume-rendered 3D imaging o Cine MR: Used for functional cardiac assessment and visualization of flow jets and valvular regurgitation o Phase-contrast MRA: Used for detection of pulmonary vein anastomotic stenosis Top Differential Diagnoses  Cor triatriatum  Hypoplastic left heart syndrome  Persistent fetal circulation syndrome, primary pulmonary hypertension Pathology  3 types o Supracardiac TAPVR (type I): “Vertical” common pulmonary vein carries blood from both lungs and joins left innominate vein o Cardiac TAPVR (type II): Common pulmonary vein joins coronary sinus or right atrium directly o Infracardiac TAPVR (type III): Common pulmonary vein traverses diaphragm to join portal vein, ductus venosus, or inferior vena cava

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(Left) Graphic shows pulmonary veins forming a retrocardiac common vein that descends below the diaphragm to drain into the inferior vena cava (IVC) (left-to-right shunt). An atrial septal defect (ASD) allows for right-to-left shunting resulting in an admixture lesion. (Right) AP radiograph shows a normal-sized heart but increased perihilar opacity due to pulmonary edema in a patient with infradiaphragmatic TAPVR (type III). As in this case, chest radiographic findings in TAPVR are often nonspecific.

(Left) Coronal CTA image shows multiple pulmonary veins draining into a vertical vein in a patient with supracardiac TAPVR (type I). (Right) Sagittal reformat CTA shows the left-sided pulmonary veins draining into a dominant single large vein , which then extends below the diaphragm and into the IVC , consistent with type III TAPVR. There is absence of the atrial septum . ASDs are common in patients with TAPVR. P.3:31

TERMINOLOGY Abbreviations  Total anomalous pulmonary venous return (TAPVR) Synonyms  Total anomalous pulmonary venous connection Definitions  Embryologic failure of common pulmonary vein to connect to left atrium o Abnormal connection of pulmonary veins to right atrium, coronary sinus, systemic veins, or systemic vein tributaries, resulting in left-to-right shunt o Atrial septal defect (ASD) of varying size (right-to-left shunt), resulting in admixture lesion IMAGING 243

Diagnostic Imaging Cardiovascular General Features  Best diagnostic clue o No pulmonary veins connecting to left atrium Radiographic Findings  Radiography o “Snowman” heart appearance on chest radiograph (type I) o Indistinguishable from ASD on chest radiograph (type II) o Small heart, reticular pattern in lungs; edema on chest radiograph (type III) o Cardiomegaly (types I and II), small heart (type III) o Shunt vascularity (types I and II), pulmonary edema (type III) o Left vertical vein may be visible in type I CT Findings  3D CT angiography o Used for pre- and postoperative pulmonary vein caliber measurements o Excellent for preoperative determination of anatomy and drainage site o May demonstrate ASD o Enlarged right atrium and right ventricle  Thickened interlobular septa, peribronchial cuffing, and ground-glass opacity suggest postoperative anastomotic pulmonary venous stenosis MR Findings  Cardiac gated T1WI o Anomalous connection is best seen in axial plane  Gadolinium-enhanced MRA o Allows for multiplanar reformations and volume-rendered 3D imaging o Best pulse sequence to define anatomy  Cine MR o Used for functional cardiac assessment and visualization of flow jets and valvular regurgitation o May demonstrate ASD and enlarged right atrium and right ventricle  Phase-contrast MRA o Used for detection of pulmonary vein anastomotic stenosis o Flow velocities > 100 cm/s are diagnostic Ultrasonographic Findings  Abdominal ultrasound in type III may demonstrate large infradiaphragmatic vascular channel from thorax with flow towards abdomen o Variable intrahepatic or extrahepatic connection  Blood eventually drains into inferior vena cava, hepatic vein, portal vein, or ductus venosus o May demonstrate area of narrowing with flow acceleration Echocardiographic Findings  Echocardiogram o Lack of connection of pulmonary veins to left atrium o Right-sided chamber enlargement in types I and II o Patent foramen ovale (PFO) o Associated cardiac and abdominal situs abnormalities o Limited assessment of postoperative venous obstruction Angiographic Findings  Conventional o Seldom required for primary diagnosis o After repair: For diagnosis and treatment of anastomotic pulmonary venous stenosis Imaging Recommendations  Echocardiography for primary diagnosis  CT or MR for postoperative pulmonary vein anastomotic stenosis DIFFERENTIAL DIAGNOSIS Cor Triatriatum  Pulmonary venous connection has occurred but remains stenotic  Membrane incompletely divides atrium in posterior and anterior chambers Hypoplastic Left Heart Syndrome  Pulmonary blood returns to left atrium; atretic or hypoplastic mitral valve causes shunting via ASD into right atrium 244

Diagnostic Imaging Cardiovascular  Small left ventricle and ascending aorta  Persistent ductus arteriosus with retrograde aortic flow towards arch vessels Persistent Fetal Circulation Syndrome or Primary Pulmonary Hypertension  Associated with severe hyaline membrane disease, meconium aspiration PATHOLOGY General Features  Genetics o No specific genetic defect is found o Occasionally associated with other complex cyanotic heart disease, asplenia syndrome, or atrioventricular canal  3 types o Type I: Supracardiac TAPVR  “Vertical” common pulmonary vein carries blood from both lungs and joins left innominate vein o Type II: Cardiac TAPVR P.3:32  Common pulmonary vein joins coronary sinus or right atrium directly Type III: Infracardiac TAPVR  Common pulmonary vein traverses diaphragm to join portal vein, ductus venosus, or inferior vena cava  Hemodynamics o All pulmonary venous return is to right heart (extracardiac left-to-right shunt) o Intracardiac right-to-left shunt is through ASD or PFO o All types are admixture lesions  Low systemic blood flow may lead to associated hypoplasia of left-sided cardiac chambers  Embryology o Lack of normal incorporation of primitive common pulmonary vein into posterior wall of left atrium o Persistence and enlargement of embryological pathways for pulmonary venous return via umbilicovitelline and cardinal veins  Pathophysiology o All types have PFO to allow for obligatory right-to-left flow, leading to varying degrees of cyanosis (less severe in types I and II: Pulmonary hypercirculation) o Nonobstructive TAPVR (types I and II): ASD physiology, pulmonary plethora, congestive heart failure o Obstructive TAPVR (type III): Common pulmonary vein enters higher pressure portal system → pulmonary venous congestion and edema Staging, Grading, & Classification  Category: Cyanotic o Heart size and pulmonary vascularity depend on type Gross Pathologic & Surgical Features  Corrective surgery connects common pulmonary vein via window with left atrium, and all other abnormal pulmonary venous connections are ligated CLINICAL ISSUES Presentation  Clinical profile o Symptom severity depends on interatrial connection size and pulmonary resistance  Types I and II: Initially asymptomatic, followed by congestive heart failure  Type III: Severe cyanosis at birth  Patent ductus arteriosus: Persistent fetal circulation Demographics  Epidemiology o 1-3% of congenital heart disease, more frequent in neonatal period  2% of deaths due to congenital heart disease in 1st year of life Natural History & Prognosis  Highly variable  No patients survive without surgical treatment  Types I and II: Initially asymptomatic, with gradual development of congestive heart failure (ASD physiology) o

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Type III, obstructive forms: Death within a month After surgical repair: Determined by associated cardiac anomalies and development of pulmonary vein anastomotic stenosis Treatment  Prostaglandin E1 to improve systemic perfusion in pulmonary hypertension  Early surgical anastomosis of pulmonary venous confluence to left atrium DIAGNOSTIC CHECKLIST Consider  Volume-rendered 3D imaging to define anatomy  Look for anastomotic pulmonary vein stenoses on postoperative CTA or MRA  Look for connection with left atrium to exclude cor triatriatum (if no connection to right atrium) or unroofed coronary sinus (if coronary sinus collects pulmonary veins and drains into right atrium) SELECTED REFERENCES 1. Husain SA et al: Total anomalous pulmonary venous connection: factors associated with mortality and recurrent pulmonary venous obstruction. Ann Thorac Surg. 94(3):825-31; discussion 831-2, 2012 2. Molinari F et al: Total anomalous pulmonary venous return with connection to the supradiaphragmatic inferior vena cava: assessment and diagnosis by multidetector computed tomography. Heart Lung Circ. 20(5):341-2, 2011 3. Seale AN et al: Total anomalous pulmonary venous connection: morphology and outcome from an international population-based study. Circulation. 122(25):2718-26, 2010 4. Lakshminrusimha S et al: Use of CT angiography in the diagnosis of total anomalous venous return. J Perinatol. 29(6):458-61, 2009 5. Oh KH et al: Multidetector CT evaluation of total anomalous pulmonary venous connections: comparison with echocardiography. Pediatr Radiol. 39(9):950-4, 2009 6. Vavas E et al: Total anomalous pulmonary venous connection in an adult: comprehensive multimodality evaluation. Congenit Heart Dis. 4(5):384-6, 2009 7. Ferguson EC et al: Classic imaging signs of congenital cardiovascular abnormalities. Radiographics. 27(5):1323-34, 2007 8. Gallego C et al: Congenital hepatic shunts. Radiographics. 24(3):755-72, 2004 9. Chen SJ et al: Validation of pulmonary venous obstruction by electron beam computed tomography in children with congenital heart disease. Am J Cardiol. 87(5):589-93, 2001 10. Videlefsky N et al: Magnetic resonance phase-shift velocity mapping in pediatric patients with pulmonary venous obstruction. J Am Coll Cardiol. 38(1):262-7, 2001 11. Kim TH et al: Helical CT angiography and three-dimensional reconstruction of total anomalous pulmonary venous connections in neonates and infants. AJR Am J Roentgenol. 175(5):1381-6, 2000 12. Livolsi A et al: MR diagnosis of subdiaphragmatic anomalous pulmonary venous drainage in a newborn. J Comput Assist Tomogr. 15(6):1051-3, 1991 13. Duff DF et al: Infradiaphragmatic total anomalous pulmonary venous return. Review of clinical and pathological findings and results of operation in 28 cases. Br Heart J. 39(6):619-26, 1977 P.3:33

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(Left) AP radiograph shows increased vascularity and a curvilinear density overlying the mediastinum , which may be mistaken for a normal thymus. However, this curvilinear structure can be seen extending into the middle mediastinum . (Right) Coronal maximum-intensity projection image in the same patient shows that the large anomalous draining pulmonary vein empties into an enlarged left brachiocephalic vein , which then drains into the enlarged superior vena cava (SVC) .

(Left) Coronal oblique reformation demonstrates a large vascular structure receiving inflow from the right pulmonary veins and left pulmonary veins . This large anomalous vein courses over the aorta and eventually drain into the superior vena cava in this patient with TAPVR. (Right) 3D reconstruction from a cardiac MR shows confluence of all pulmonary veins into an anomalous vein that courses below the diaphragm and eventually drains into the right atrium.

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(Left) Volume-rendered 3D CTA shows a common vein draining into SVC and the right upper pulmonary vein draining directly into SVC. This is considered “mixed” anomalous pulmonary return. (Right) Oblique coronal MRA shows all 4 pulmonary veins collecting in a common vein posterior to the left atrium in a patient with TAPVR. In the setting of congenital heart disease, it is often advantageous to use nonstandard planes to evaluate the course of vascular and cardiac structures.

Partial Anomalous Pulmonary Venous Return Partial Anomalous Pulmonary Venous Return Jonathan Hero Chung, MD Key Facts Terminology  Partial anomalous pulmonary venous return (PAPVR)  Congenital anomaly in which pulmonary veins drain into systemic veins rather than into left atrium Imaging  Radiography o Rarely identifies abnormal vein o Obstructive venous drainage may cause pulmonary congestion o If significant left-to-right shunt: Cardiomegaly and plethoric pulmonary vasculature  CT o Abnormal drainage of pulmonary veins o Multiplanar capabilities of isovolumetric acquisition are helpful in identifying abnormal vein o Right-sided PAPVR draining into superior vena cava associated with sinus venosus atrial septal defect  MR o Phase-contrast imaging is helpful in determining shunt fraction Top Differential Diagnoses  Left superior vena cava  Pulmonary varix  Left superior intercostal vein Pathology  Persistent embryologic systemic venous connections  Right-sided PAPVR into superior vena cava is associated with sinus venosus atrial septal defect Clinical Issues  Usually incidental radiographic finding  Usually normal life span if shunt < 2:1  Consider surgical or percutaneous closure of atrial septal defect

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(Left) Axial thick volume-rendered image from CTA shows an abnormal vessel along the left lateral margin of the aortic arch. This imaging finding is essentially diagnostic of either a left-sided superior vena cava (SVC) or an anomalous pulmonary vein. (Right) 3D volume-rendered image of the heart and great vessels in the same patient shows that the abnormal vessel extends from the left hilum and drains into the left brachiocephalic vein , diagnostic of partial anomalous pulmonary venous return. Note SVC .

(Left) Axial oblique MIP image shows partial anomalous pulmonary venous drainage of the right upper lobe vein into the SVC rather than into the left atrium. In addition to the normal right SVC, there is also a left SVC . (Right) Cardiac CTA image in the same patient shows a defect within the superior aspect of the interatrial septum , diagnostic of a sinus venosus ASD. There is a strong association between anomalous pulmonary venous drainage into the SVC and sinus venosus ASDs. P.3:35

TERMINOLOGY Abbreviations  Partial anomalous pulmonary venous return (PAPVR) Definitions  Congenital anomaly in which pulmonary veins drain into systemic veins rather than into left atrium o Scimitar syndrome is right-sided PAPVR draining into inferior vena cava (IVC) accompanied by hypoplasia of right lung and dextroposition of heart IMAGING General Features  Best diagnostic clue 249

Diagnostic Imaging Cardiovascular o Demonstration of abnormal pulmonary vein drainage on cross-sectional imaging modality Location o Right side: Drainage to superior vena cava (SVC), azygous vein, right atrium, coronary sinus, and IVC  Scimitar vein courses from right mid lung inferiorly to below diaphragm o Left side: Superior drainage into brachiocephalic vein Radiographic Findings  Radiography o Abnormal vein is rarely identified o Scimitar vein is curvilinear anomalous vein coursing inferiorly from mid right lung usually into IVC  Commonly associated with small right lung, cardiac dextroposition, and bilateral left-sided bronchial branching o Obstructive venous drainage may cause pulmonary congestion o If significant left-to-right shunt: Cardiomegaly (right heart) CT Findings  CECT o Abnormal pulmonary vein drainage o Multiplanar capabilities of isovolumetric acquisition are helpful in identifying abnormal vein o Right-sided PAPVR draining into SVC associated with sinus venosus atrial septal defect (ASD) MR Findings  Double IR FSE can show ASD; phase-contrast imaging can quantify left-to-right shunts  Enlarged right atrium and ventricle in case of concomitant sinus venosus ASD DIFFERENTIAL DIAGNOSIS Left Superior Vena Cava  2 vessels ventral to left upper lobe bronchus: Left SVC and left superior pulmonary vein  Drains into coronary sinus; right SVC may be absent Pulmonary Varix  Acquired or development dilatation of pulmonary vein at its entrance to left atrium Left Superior Intercostal Vein  Aortic “nipple” on chest radiograph PATHOLOGY General Features  Etiology o Persistent embryologic systemic venous connections  Associated abnormalities o Right PAPVR into SVC: Sinus venosus ASD o Scimitar syndrome: ASD, systemic blood supply to lung, extralobar sequestration, horseshoe lung, and pulmonary arteriovenous malformation CLINICAL ISSUES Presentation  Most common signs/symptoms o Usually incidental radiographic finding o Scimitar syndrome  Infants can have severe CHF and pulmonary hypertension  Older children have less severe symptoms Demographics  Epidemiology o Incidence: 0.5-0.7% Natural History & Prognosis  Usually normal life span if shunt < 2:1 Treatment  Options, risks, complications o Inadvertent clipping causes persistent localized pulmonary edema o Contralateral pneumonectomy: PAPVR shunt may now account for majority of cardiac output  May require reimplanting aberrant vein into left atrial appendage o Consider surgical or percutaneous closure of ASD DIAGNOSTIC CHECKLIST Image Interpretation Pearls  If PAPVR is detected, look carefully for ASD 

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Diagnostic Imaging Cardiovascular SELECTED REFERENCES 1. Generali T et al: Partial anomalous pulmonary vein connection. J Card Surg. 27(2):245, 2012 2. Halpin JS et al: Partial anomalous pulmonary venous return through a left subaortic vein. J Thorac Imaging. 27(6):W177-9, 2012 3. Vyas HV et al: MR imaging and CT evaluation of congenital pulmonary vein abnormalities in neonates and infants. Radiographics. 32(1):87-98, 2012 4. Aramendi JI et al: Partial anomalous pulmonary venous connection to the superior vena cava. Ann Thorac Surg. 91(4):e64-6, 2011 5. Harrison LH Jr et al: Partial anomalous pulmonary venous connection in adults: a simplified approach. Ann Thorac Surg. 89(1):283-5, 2010 6. Dillman JR et al: Imaging of pulmonary venous developmental anomalies. AJR Am J Roentgenol. 192(5):1272-85, 2009 7. Ho ML et al: MDCT of partial anomalous pulmonary venous return (PAPVR) in adults. J Thorac Imaging. 24(2):89-95, 2009 8. Pryshchepau M et al: Anomalous partial pulmonary venous drainage. Eur J Cardiothorac Surg. 36(5):933, 2009

Section 4 - Valvular Approach to Valvular Disease Approach to Valvular Disease Christopher M. Walker, MD Suhny Abbara, MD, FSCCT Introduction Valvular heart disease is common, with surgical therapy of valve disease comprising about 10-20% of all cardiac surgical procedures. Aortic stenosis is the third most common cardiovascular disease, trailing only hypertension and coronary artery disease. Echocardiography and chest radiography are the initial modalities used to evaluate patients with suspected valvular dysfunction. Echocardiography is widely available and portable, has excellent temporal resolution, and is relatively cost effective. The major limitations of echocardiography include nondiagnostic examinations secondary to patient body habitus or emphysema and variability among different operators regarding measurements of ejection fraction or degree of valve regurgitation. Computed tomography (CT) and magnetic resonance (MR) imaging are used to characterize valvular dysfunction in select patients. MR is beneficial as it can quantify ventricular mass and function, which aids the surgeon in appropriately timing valve replacement surgery. CT is complementary as it can be used in patients with contraindications to MR (i.e., pacemaker or claustrophobia) but is limited due to its use of ionizing radiation. This chapter describes the role of CT and MR in the evaluation of diseases that affect cardiac valves. Anatomy and Physiology There are two atrioventricular (tricuspid and mitral) and two semilunar (pulmonic and aortic) valves. The pulmonic and aortic valves each have three cusps and open when ventricular pressure exceeds the main pulmonary artery or aortic pressure, respectively. The tricuspid and mitral valves open during ventricular diastole, whereas the pulmonic and aortic valves open during ventricular systole. An important identifying feature of the morphologic right ventricle is that the tricuspid and pulmonic valves are separated from each other by a muscular ridge of tissue called the crista supraventricularis, whereas the mitral and aortic valves are in fibrous continuity. The main function of the cardiac valves is to allow unidirectional blood flow through the cardiac chambers while maintaining a low pressure gradient. If valvular regurgitation or stenosis develops, the ventricle responds with either ventricular dilatation or muscular hypertrophy. Generally, valve regurgitation causes chamber dilatation, whereas valve stenosis causes chamber hypertrophy. Role of MR Steady-state free precession (SSFP) MR with ECG gating has largely replaced gradient-echo sequences for the evaluation of cardiac valve structure and valve morphology and for measuring the orifice area. Images should be acquired in multiple orthogonal planes to the valve of interest in addition to the standard cardiac views (e.g., fourchamber, paraseptal long-axis, and three-chamber). Valvular stenosis and regurgitation cause turbulent blood flow, leading to phase dispersion and signal voids (black jets). A black jet originating from the valve directed forward into the receiving chamber or vessel indicates valvular stenosis, whereas a black jet directed retrograde from the valve indicates valvular regurgitation. Unlike echocardiography, MR cannot use the size and magnitude of the black jet to quantify the degree of valve stenosis or regurgitation; these should be used simply as markers to diagnose the abnormality. MR is widely considered the noninvasive gold standard for determining myocardial mass, ventricular volumes, and ventricular function. Ventricular function and volumes are calculated after tracing the ventricular cavity contour at 251

Diagnostic Imaging Cardiovascular end-systole and end-diastole usually on short-axis images. These measurements are summed to yield end-systolic and end-diastolic volumes, which are then used to calculate ventricular stroke volume and ejection fraction. The myocardial mass is calculated by tracing the endocardial and epicardial borders at end-diastole and summing the measurements. The calculated volumes and myocardial mass are corrected for the patient's body surface area and then compared to a standard table of reference normals. Calculated ventricular function and volumes are used by the surgeon and cardiologist to assess the effect of the valvular abnormality on the heart and may influence the timing of surgery. Several direct and indirect methods are available for quantifying the degree of valve regurgitation or stenosis. Direct quantification of the degree of valve regurgitation or stenosis can be performed with velocity-encoded cine (VEC) phase-contrast techniques. This sequence is usually prescribed perpendicular to the valve of interest. VEC phasecontrast MR produces magnitude and phase images from each data set. The magnitude images comprise a bright blood gradient-echo sequence that is used primarily to define vessel anatomy and prescribe a region of interest (ROI). Flow velocity and direction are encoded in each voxel by gray scale (i.e., different shades of white and black) on the accompanying phase images. The maximum through-plane velocity (v) across the valve of interest can be measured with this technique and is used to estimate the pressure gradient (ΔP) across the valve through the modified Bernoulli equation, where ΔP= 4v2. The pressure gradient can then be compared against a reference table to determine the severity of valve stenosis. Flow-volume curves can be generated by drawing a ROI at each point of the cardiac cycle and multiplying the average flow velocity by the total area of the ROI. The regurgitant volume is then calculated by dividing the amount of regurgitation by the amount of forward flow. Measurements should be corrected with the use of a phantom. Direct measurement of the maximal valve opening area or the size of the regurgitation orifice (so-called valve planimetry) can be performed with SSFP imaging in a plane parallel to the valve of interest. Indirect quantification of valve regurgitation can be performed by comparing ventricular stroke volumes. Under normal circumstances, the right and left ventricular stroke volumes are equal. In the presence of a single regurgitant valve, the stroke volume increases on the abnormal side, and the difference between the stroke volumes of the two ventricles is equal to the regurgitant volume. Importantly, this method is inaccurate when there are cardiac shunts or when more than one valve is abnormal. Role of CT CT is a second-line modality in evaluating patients with suspected valvular disease due to its use of ionizing radiation and intravenous contrast. CT is used in select P.4:3 patients, such as those who have contraindications to MR (e.g., claustrophobia or pacemaker) or those with nondiagnostic or limited echocardiography due to body habitus or emphysema. CT can also help in screening for coronary artery disease prior to valve replacement surgery and in detecting complications following valve surgery. CT has a superior spatial resolution and image acquisition time but inferior temporal resolution when compared with both echocardiography and MR. Ideally, valve evaluation is conducted on a 64-slice (or higher) CT scanner and takes about 8 seconds to perform. Images should be acquired at 0.60-0.75 mm to obtain a data set with isotropic voxels and high spatial resolution. The voltage, pitch, and tube current vary depending on the patient's weight and heart rate. Patients with low body mass index can have diagnostic image quality with voltages of either 80 kV or 100 kV, whereas obese patients may require voltages up to 140 kV. Computer software that allows automated adjustment of many parameters is now available. In absence of contraindications, oral or intravenous β-blocker are used at many institutions to achieve a target heart rate of 60 beats per minute or less in an effort to limit or reduce motion artifact. Oral medication must be administered hours before the examination in order to achieve the appropriate effect. Sublingual nitroglycerin (300600 µg) may be used to maximally dilate vasculature when simultaneous evaluation of coronary arteries is desired. Intravenous contrast is injected as a bolus through an antecubital vein at a rate of 4-7 mL/s using either bolus tracking or test bolus (which triggers acquisition when the contrast arrives in the ascending aorta) software. Contrast is injected using either a biphasic or triphasic protocol. Variable amounts of contrast (50-120 mL) are used and vary depending on scan length, flow rate, and patient size. Images are acquired at mid or end inspiration. Valve assessment typically requires cine imaging through the valve of interest with retrospective gating to visualize leaflet mobility and coaptation. Tube current modulation, limited field of view, and iterative reconstruction are helpful in reducing the radiation dose. Alternatively, newer scanners allow prospective triggered wide window acquisitions to evaluate function. The degree of aortic valve calcification positively correlates with the aortic stenosis severity. The amount of calcification can be quantified using an Agatston score, although this practice has not been widely adopted. Measurement of maximal valve area (valve planimetry) has shown excellent correlation in predicting the severity of aortic stenosis when compared with direct measurement by transesophageal echocardiography or indirect measurement using the continuity equation in transthoracic echocardiography. 252

Diagnostic Imaging Cardiovascular Transcatheter Aortic Valve Replacement Transcatheter aortic valve replacement can be performed via transfemoral/subclavian, transapically, or transaortic access. Preprocedural CTA is increasingly used to assess aortic size (e.g., aortic root, minimal aortic diameter), degree of aortic valve calcification, distance of the coronary arteries to the aortic annulus, and peripheral access suitability (e.g., minimal iliac artery diameter, minimal common femoral artery diameter, and presence of dissection, vascular tortuosity, and vascular calcification). The currently available prosthetic valves can be used if a patient has an aortic annulus diameter of 18-29 mm (ideally measured during systole), an annulus perimeter of 63-87 mm, and an ascending aorta measuring ≤ 43 mm; therefore, accurate annulus and aortic measurements are a necessity prior to transcatheter aortic valve replacement. Special Cases Valvular Masses Most valvular masses are not neoplastic but rather thrombi or vegetations related to endocarditis. Endocarditis occurs in about 6 in 100,000 people per year and is more common in intravenous drug users, patients with poor dental hygiene, and patients with prosthetic valves. Echocardiography is the primary modality used to diagnose vegetations. Gated CT is advantageous as it is able to depict most vegetations measuring > 1 cm and can accurately delineate a perivalvular abscess and important extracardiac findings (e.g., septic emboli). Papillary fibroelastoma is the most common primary valvular neoplasm. It is rare and typically affects left-sided valves (aortic > mitral). Patients are generally asymptomatic but may present with symptoms/signs of peripheral thromboembolism (e.g., stroke or limb ischemia). Most fibroelastomas are < 1 cm in size and generally have low T2 signal on MR. They may be difficult to visualize on CT or MR due to their small size. Larger tumors enhance following administration of a gadolinium chelate contrast agent. Myxoma, sarcoma, hemangioma, or metastatic tumors may rarely involve cardiac valves. Valvular Prostheses Valve replacement surgery is most commonly performed on the aortic and mitral valves. There are two types of artificial valves: Bioprosthetic (tissue) and mechanical. Tissue valves have a shorter lifespan compared to artificial valves but do not require anticoagulation. Annuloplasty with a ring device is most commonly used in the setting of tricuspid or mitral regurgitation. Important Considerations for Reporting Valvular anatomy and morphology  Number of leaflets: Unicuspid, bicuspid, or tricuspid  Morphology of leaflets: Prolapse, rupture, calcification, thickening, or fusion  Presence of perivalvular aneurysm, abscess, etc.  Cross-sectional valvular area Valvular function  Stenosis or regurgitation  Valve opening and closing pattern Valvular affect on cardiac function  Left ventricular ejection fraction, right ventricular ejection fraction, and end-diastolic volumes  Diastolic filling  Regional and global ventricular wall motion  Myocardial mass Associations that may influence surgical approach  Myocardial viability (MR)  Obstructive coronary artery disease (CT)  Thrombus  Aortic coarctation P.4:4

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(Left) Graphic demonstrates the anatomy of the cardiac skeleton between the atria and ventricles. The cardiac skeleton consists of thick fibrous connective tissue and provides support for the valve orifices. Note that the mitral and aortic valves are in fibrous continuity, whereas the tricuspid and pulmonic valves are separated by a muscular infundibulum. Also note anomalous left main coronary artery. (Right) Axial SSFP image shows a normal trileaflet aortic valve during ventricular systole.

(Left) Four-chamber SSFP MR shows normal thin leaflets of the tricuspid and mitral valves, which are closed during ventricular systole. The hingepoint of the septal tricuspid valve leaflet is normally more apical than the septal mitral valve leaflet hingepoint. (Right) Four-chamber SSFP MR in the same patient shows normal thin leaflets of the tricuspid and mitral valves, which are open during ventricular diastole.

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(Left) RVOT SSFP MR shows a normal, thin, closed pulmonic valve situated on top of the right ventricular outflow tract , which connects it to the body of the right ventricle and separates it from the tricuspid valve. (Right) LVOT SSFP MR shows that the aortic valve is open and the mitral valve is closed during ventricular systole. Note that the aortic and mitral valves are directly adjacent to each other (so-called fibrous continuity). Also note intravalvular fibrosa . P.4:5

(Left) RVOT SSFP shows the normal anatomy of the right ventricle and right-sided cardiac valves. Note that the pulmonic valve is separated from the tricuspid valve by a muscular infundibulum known as the crista supraventricularis. (Right) LVOT SSFP MR image shows a black jet originating from the aortic valve directed posteriorly into the left ventricle during ventricular diastole, indicating aortic regurgitation.

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(Left) LVOT systolic SSFP MR shows a black jet originating from the aortic valve directed into the ascending aorta, which indicates aortic stenosis. Importantly, the size and magnitude of the jet cannot be used to quantify the degree of stenosis or regurgitation on MR as it varies depending on the echo time used in acquisition. (Right) Four-chamber SSFP MR during systole shows a regurgitant jet extending retrograde from the mitral valve to the posterior wall of the left atrium.

(Left) Magnitude image from a velocity-encoded cine (VEC) MR sequence obtained during systole shows a fish-mouth appearance of the aortic valve, consistent with a bicuspid aortic valve . (Right) In this phase image from a VEC MR sequence from the same patient, direction is encoded into the signal so that blood flowing toward the head is encoded as bright signal and blood flowing toward the feet, as in the descending aorta , is encoded as dark signal. P.4:6

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(Left) Magnitude image from a VEC MR sequence obtained during diastole shows incomplete coaptation of the aortic valve leading to aortic regurgitation. (Right) Corresponding phase image shows aortic regurgitation . In the magnitude image, blood flowing both in and out of plane is designated as bright signal, whereas the phase image encodes the direction of blood flow, confirming retrograde regurgitant flow. VEC MR is useful in quantitating the degree of regurgitation or valve stenosis.

(Left) Aortic valve short-axis cardiac CT during diastole shows a heavily calcified aortic valve with thickening of all 3 leaflets. Without systolic images, bicuspid or unicuspid valve cannot be excluded, as leaflets may be fused. (Right) Aortic valve short-axis CT obtained at mid-systole in the same patient shows a markedly reduced opening area of the aortic valve, indicating severe stenosis. The valve is confirmed to be tricuspid, although partial peripheral fusion of some cusps has occurred.

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(Left) Short-axis CT obtained at mid-systole in the same patient has a region of interest tracing the systolic orifice area 2 2 of the valve that is 0.78 cm (valve planimetry). A normal opening area is > 2 cm , and a stenosis is considered severe 2 2 if the area is < 1cm . Opening areas < 0.7 cm are often classified as critical stenoses. (Right) Axial CECT shows a soft tissue nodule attached to the aortic valve and complete lower lobe collapse in an intravenous drug user with endocarditis. P.4:7

(Left) Axial CECT shows a soft tissue nodule attached to the tricuspid valve and complete lower lobe collapse in an intravenous drug user with endocarditis. The tricuspid valve is the most common location for a vegetation in a patient who abuses intravenous drugs. (Right) Four-chamber view SSFP image shows a well-seated mitral valve prosthesis . There is a round low-signal nodule attached to the ventricular side of the prosthesis, which represents a thrombus.

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(Left) Axial oblique gated cardiac CTA show a small 3 mm soft tissue nodule arising from the aortic valve . The differential diagnosis for this finding includes a vegetation, thrombus, or tumor. (Right) Sagittal oblique image from the same patient shows a small 3 mm soft tissue nodule arising from the aortic valve . At surgery, this was proven to be the most common valvular tumor, a papillary fibroelastoma. The aortic valve is the most common location for this tumor.

(Left) Short-axis cardiac CT image shows a bicuspid aortic valve with fusion of the left and right coronary cusps, the most common variant of congenital bicuspid aortic valve. A small, partially calcified raphe is noted . (Right) Oblique sagittal multiplanar reformat from a cardiac CT scan shows coarctation in the descending thoracic aorta . Bicuspid aortic valve is associated with both coarctation and pseudocoarctation.

Aortic Stenosis Key Facts Terminology  Narrowing of aortic outflow tract, which causes flow obstruction o Valvular (most common); subvalvular (rare); supravalvular (extremely rare) Imaging  Doppler echocardiogram: High transvalvular velocity systolic jet and high pressure gradient  CT, MR, transesophageal echocardiogram: Narrowing of aortic valve orifice (area < 1.5 cm2)  Radiograph, CT: Severe calcification Top Differential Diagnoses  Degenerative calcified aortic stenosis  Rheumatic heart disease 259

Diagnostic Imaging Cardiovascular  Bicuspid aortic valve  Subvalvular aortic stenosis Clinical Issues  Asymptomatic over long period, symptoms late (syncope, dyspnea, heart failure)  Dominant cause: Bicuspid valve (< 70 years) or degenerative calcified stenosis (> 70 years)  Aortic valve replacement is only effective treatment (surgical or transcatheter route) Diagnostic Checklist  Radiograph, CT: Calcific stenosis is predominant type (almost 100% have calcification)  Echocardiography: Increased transvalvular pressure gradient and velocity (standard tool)  Cardiac CT: Planimetric sizing of aortic valve orifice area  Radiograph: Valvular calcification, round apex (concentric left ventricular hypertrophy); late signs of heart failure (left ventricular dilatation)

(Left) Cardiac CT axial 3D VRT reconstructed through aortic valve plane in a patient with degenerative aortic stenosis shows a tricuspid valve (“Mercedes star” configuration) with severe leaflet calcification of all leaflets (white spots). Note, tricuspid nature of the aortic valve cannot be ascertained off diastolic-only images, as 2 cusps may be fused resulting in functional bicuspid valve. (Right) 3D VRT 3-chamber view in same patient shows aortic and mitral annular calcification.

(Left) Axial oblique cardiac CT shows a tricuspid valve that is severely calcified and has fibrous thickening of leaflets, indicating degenerative or rheumatic nature of the disease. (Right) Double oblique cardiac CT in aortic valve plane shows a bicuspid valve with a calcified raphe between the right and left coronary cusps. Note the decreased systolic aortic valve orifice area . P.4:9

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TERMINOLOGY Abbreviations  Aortic stenosis (AS) Definitions  Narrowing of aortic outflow tract, which causes flow obstruction o Valvular (most common) o Subvalvular (rare) o Supravalvular (extremely rare) IMAGING General Features  Best diagnostic clue o High-velocity systolic blood jet ejected into ascending aorta  Morphology o Thickening, fusion, &/or calcification of aortic valve apparatus o Valvular calcification  Increased transvalvular pressure gradient and velocity  Concentric left ventricular hypertrophy (> 12 mm myocardium thickness) Radiographic Findings  Radiography o Chest x-ray  Enlarged cardiac silhouette in severe AS, late stage indicating heart failure (AP view)  Rounding of left ventricular apex (due to concentric hypertrophy) (AP view)  Aortic valve calcification (lateral view)  Post-stenotic ascending aortic dilatation may be present  Aortic sclerosis and elongation are common CT Findings  NECT o Calcium score > 1,100 Agatston score units is cut-off for severe AS  93% sensitivity; 82% specificity  Cardiac gated CTA o Fibrous leaflet thickening (hypodense) > 2 mm and calcification (hyperdense) o Concentric left ventricular hypertrophy (> 12 mm septal thickness end diastolic) o Planimetric measurement of aortic valve orifice area (AVA) during mid systole (5-35% of RR-interval) o Post-stenotic dilatation of ascending aorta > 35 mm o Left ventricular dysfunction and left ventricular dilatation in severe AS (late stage) MR Findings  Systolic flow void (jet) into proximal aorta on bright blood cine imaging  Left ventricular hypertrophy in severe AS, ± dilatation if left ventricular failure occurs  Calculation of aortic valve area  Phase-contrast MR: Calculation of peak systolic velocity and gradients Echocardiographic Findings  Echocardiogram o Transthoracic echocardiography (TTE)  Calcified, thickened valve leaflets  Left ventricular dysfunction, left ventricular hypertrophy and enlargement o Transesophageal echocardiography (TEE)  Calculation of transvalvular gradient and aortic valve area  Planimetry of anatomic aortic valve orifice area  Visualization of morphology (bicuspid vs. tricuspid) o Color and pulsed Doppler  Indications of severe stenosis (if normal left ventricular function)  ↑ transvalvular pressure gradient (> 50 mm Hg)  ↑ transvalvular velocity (> 4 m/s)  Calculation of aortic valve orifice area by continuity equation (velocity time integral [VTI]) o TTE is primary imaging modality for diagnosis and staging of disease severity Angiographic Findings 261

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Conventional o Systolic jet into aorta and severe calcification o Right and left catheterization allows valve aperture surface, cardiac function, and pressure measurements in preoperative assessment o Valvular gradient measured during catheter pull-back o Calculation of aortic valve orifice area (by using Gorlin formula) Imaging Recommendations  Best imaging tool o Echocardiography, MR  Protocol advice o ECG-gated cardiac CT  Image reconstruction during mid systole (12-20% RR-interval)  Multiplanar reformations (MPRs) for planimetry of aortic valve orifice area DIFFERENTIAL DIAGNOSIS Degenerative Calcified Aortic Stenosis  Marked fibrous/calcific thickening of all 3 leaflets  Calcification more prominent at base of leaflets  Symptoms present in 7th decade or beyond Rheumatic Heart Disease  Thickening predominately along commissural edge  Accompanies rheumatic mitral stenosis Bicuspid Aortic Valve  2 equal (no raphe) or unequal (fused with raphe) cusps  Either “congenital” (fused raphe) or “secondary degenerative” (cusp fusion) o Congenital  Prevalence of 2%  Symptoms present in 4th or 5th decade (due to early degeneration and leaflet thickening)  Association with coarctation and aneurysm of aorta o Secondary degenerative (“functional”) in case of severe degenerative disease and fused leaflets Subvalvular Aortic Stenosis  Congenital subvalvular membrane  Idiopathic hypertrophic subaortic stenosis (IHSS) caused by asymmetric thickening of ventricular septum P.4:10

Supravalvular Aortic Stenosis  Extremely rare; associated with Williams-Beuren syndrome  Hourglass narrowing above aortic bulbus Rare Causes  Infective endocarditis: Obstruction by vegetations  Radiation valvulitis PATHOLOGY General Features  Etiology o Degenerative/calcifying disease o Rheumatic (less common)  Thickening, fusion, and calcification of aortic leaflets Staging, Grading, & Classification  3 grades by echocardiography o Mild (grade I)  AVA > 1.5 cm2  Mean pressure gradient < 25 mm Hg o Moderate (grade II)  AVA = 1-1.5 cm2  Transvalvular pressure gradient = 25-40 mm Hg o Severe (grade III)  AVA < 1 cm2  Critical (surgery usually indicated) if AVA < 0.7 cm2 (gradient > 70 mm Hg) 262

Diagnostic Imaging Cardiovascular  Transvalvular pressure gradient > 40 mm Hg Gross Pathologic & Surgical Features  Stenotic cusps with nodular calcium deposits on leaflets  Calcification predominantly near base of valve Microscopic Features  Fibrous thickening and transvalvular calcification CLINICAL ISSUES Presentation  Most common signs/symptoms o Syncope, angina (chest pain), dyspnea, arrhythmia, increased risk of sudden cardiac death, and heart failure are symptoms in late stage  Other signs/symptoms o Systolic heart murmur  Clinical profile o Asymptomatic over long period (“mystery killer”) o Symptoms develop late Demographics  Age o Prevalence of 2-5% in individuals > 65 years of age; increases with age  Epidemiology o Prevalence of aortic valve calcification is 25% at mean age of 65 years Natural History & Prognosis  Bicuspid valve is dominant cause for patients < 70 years old, calcific degenerative for patients > 70 years old  Increased risk of sudden cardiac death, especially in symptomatic patients  Left ventricular hypertrophy predicts onset of symptoms Treatment  Surgical aortic valve replacement is standard treatment in patients with severe AS o Associated with coronary artery bypass grafting if needed  Mortality rate o ˜ 4% for aortic valve replacement o ˜ 7% with accompanying coronary artery bypass grafting o ˜ 10% with repair of another valve  Aortic valve replacement 10-year survival rate: ˜ 85% DIAGNOSTIC CHECKLIST Consider  Calcific AS is predominant o ˜ 100% of patients with AS have calcium  Left ventricular function is important parameter to predict outcome Image Interpretation Pearls  Valvular calcifications (seen on lateral radiograph, CT, echocardiography)  Echocardiography o Increased transvalvular pressure gradient and velocity  ECG-gated cardiac CT and cardiac MR o Narrowing of aortic valve area < 2 cm2 during mid systole  Concentric left ventricular hypertrophy and left ventricular dysfunction at late stage SELECTED REFERENCES 1. ACC/AHA et al: ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 114(5):e84-231; 2006. Review. Erratum in: Circulation. 115(15):e409, 2007. Circulation. 121(23):e443, 2010 2. Pflederer T et al: Aortic valve stenosis: CT contributions to diagnosis and therapy. J Cardiovasc Comput Tomogr. 4(6):355-64, 2010 3. Ropers D et al: Comparison of dual-source computed tomography for the quantification of the aortic valve area in patients with aortic stenosis versus transthoracic echocardiography and invasive hemodynamic assessment. Am J Cardiol. 104(11):1561-7, 2009 4. Abbara S et al: Feasibility and optimization of aortic valve planimetry with MDCT. AJR Am J Roentgenol. 188(2):35660, 2007 5. Feuchtner GM et al: Sixty-four slice CT evaluation of aortic stenosis using planimetry of the aortic valve area. AJR Am J Roentgenol. 189(1):197-203, 2007 263

Diagnostic Imaging Cardiovascular 6. Feuchtner GM et al: Multislice computed tomography for detection of patients with aortic valve stenosis and quantification of severity. J Am Coll Cardiol. 47(7):1410-7, 2006 7. Rahimtoola SH: The year in valvular heart disease. J Am Coll Cardiol. 47(2):427-39, 2006 8. Braunwald E: Valvular heart disease. In Braunwald E: Heart Disease: A Textbook of Cardiovascular Medicine. 6th ed. Philadelphia: W. B. Saunders, 2001 P.4:11

Image Gallery

(Left) AP radiograph from a patient with severe aortic valve stenosis shows a dilated heart, a rounded appearance of the cardiac apex caused by concentric left ventricular hypertrophy , and a tortuous aorta with atherosclerotic calcification . (Right) Lateral radiograph in the same patient reveals aortic valve calcifications in the upper middle 1/3 of the cardiac shadow , a finding highly suggestive of underlying aortic valve stenosis.

(Left) Axial oblique cardiac CT during systole reveals thickening and fusion of noncoronary and right coronary cusps , and a narrow systolic orifice area (0.43 cm 2) between the noncoronary and left coronary cusps , and the left coronary and right coronary cusps . (Right) Lateral oblique sagittal cardiac CT shows a “buttonhole” critical stenosis (aortic valve orifice area = 0.43 cm 2) with slightly eccentric orifice.

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(Left) Three-chamber view cardiac CT from a patient with subvalvular aortic stenosis shows a thin membrane causing left ventricular outflow tract obstruction. (Right) Echocardiogram shows increased Doppler transvalvular velocity and pressure gradients in another patient with aortic stenosis. The measured maximum velocity is 4.95 m/s, and according to the modified Bernoulli equation (gradient = 4v2), the peak gradient is calculated to be 98.01 mm Hg.

Transcatheter Aortic Valve Replacement Transcatheter Aortic Valve Replacement Sanjeev A. Francis, MD Suhny Abbara, MD, FSCCT Key Facts Terminology  Catheter-based valve replacement performed via femoral, subclavian, apical, or aortic approach Imaging  Components of a comprehensive imaging protocol for TAVR evaluation o Aortic annulus size o Thoracic and abdominal aorta o Vascular access: Assessment of ileo-femoral arteries, subclavian arteries  Cardiac CTA including abdomen/pelvis allows for comprehensive assessment prior to TAVR o Volume should include from level of aortic arch to femoral arteries o ECG-gated imaging of aortic root (prospective or retrospective triggering) o Reconstructed slice thickness should be < 1 mm Diagnostic Checklist  Comprehensive CT report should include o Acquisition information (mode, systolic vs. diastolic triggering, contrast volume) o Ascending aorta (position relative to sternum, width 40 mm from annulus) o Descending thoracic and abdominal aorta (tortuosity, atheroma, thrombus, aneurysm) o Iliofemoral arteries (minimal luminal diameter, tortuosity, calcification) o Aortic annulus (short and long diameters, area, circumference) o Aortic valve (number of cusps, degree and location of calcification) o Aortic root (diameter, distance of coronary ostia from aortic annulus) o Presence of LV thrombus

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(Left) Fluoroscopy shows a transfemoral TAVR with the catheter-based prosthetic valve positioned in the native aortic annulus prior to deployment. TEE (probe ) is used during the procedure to guide positioning and to evaluate for postprocedure complications such as aortic insufficiency. (Right) Fluoroscopy shows a prosthetic valve being deployed with balloon inflation. Adequate sizing of the aortic annulus is necessary to select the proper prosthesis size and minimize postprocedure complications.

(Left) Oblique cardiac CT of the aortic root in long axis shows the aortic annulus plane (line) and the measurement of the distance of the right coronary artery ostium to the annulus plane (double-headed arrow). (Right) Oblique cardiac CT at the aortic annulus is shown. Inserts display 3 metrics: Left = shortest and longest diameters, middle = length of circumference, and right = area. Based on available data, cardiac CT is the most accurate modality for the prediction of paravalvular leak based on annulus size. P.4:13

TERMINOLOGY Abbreviations  Transcatheter aortic valve replacement (TAVR) Synonyms  Transcatheter aortic valve implantation (TAVI)  Percutaneous aortic valve replacement Definitions  Catheter-based valve replacement performed via femoral, subclavian, apical, or aortic approach IMAGING General Features 266

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Components of comprehensive imaging protocol for TAVR evaluation o Aortic annulus  Inaccurate measurement of annulus size may lead to undersizing of prothesis and paravalvular leak  Cardiac CT performs better than 2D TEE and 3D TEE in predicting postoperative paravalvular leak due to better approximation of annulus size  3D TEE performs better than 2D TEE for assessment of annular size when compared to cardiac CT  Additional studies necessary to confirm utility of CMR in evaluation of patients for TAVR o Thoracic and abdominal aorta  Given age and associated comorbidities of patients evaluated for TAVR assessment of aortic pathology such as aneurysm, dissection, degree of atherosclerotic calcification, and tortuosity is important o Vascular access  Ileo-femoral arteries  Minimal luminal diameter necessary for sheath/introducer depends on size of valve and particular manufacturer and ranges from 6-8 mm or greater  Subclavian artery  Minimal luminal diameters and vessel tortuosity are important anatomic considerations  LV apex  In patients who are not candidates for transfemoral or trans-subclavian approach and transapical approach can be considered, which is often performed in conjunction with a surgeon; excluding LV apical thrombus is important for this approach Imaging Recommendations  Best imaging tool o Cardiac CTA including abdomen/pelvis allows for comprehensive assessment prior to TAVR  Protocol advice o Volume should include from level of aortic arch to femoral arteries o ECG-gated imaging of aortic root (prospective or retrospective triggering)  Systolic imaging may be preferable given changes in annulus size during ventricular contraction o Reconstructed slice thickness should be < 1 mm CLINICAL ISSUES Indications for TAVR  Consideration for patients who have an increased risk of mortality from traditional surgery o Surgical risk can be assessed using Society of Thoracic Surgeons (STS) score and EuroScore o At present, TAVR should not be considered for patients who are low risk for surgical AVR  Other factors that may impact surgical risk but not necessarily captured in traditional risk calculators o Frailty, prior chest radiation, extensive aortic calcifications (porcelain aorta) Outcomes With TAVR  In PARTNER (cohort B) trial, inoperable patients had lower 1-year mortality rate with TAVR vs. balloon valvuloplasty  In PARTNER (cohort A) trial, high-risk patients had similar 1-year mortality with TAVR vs. surgical AVR o TAVR associated with more vascular complications and postop aortic insufficiency, surgery associated with more bleeding and atrial fibrillation  Paravalvular AI associated with poorer outcomes, highlighting importance of accurate sizing of aortic annulus DIAGNOSTIC CHECKLIST Reporting Tips  Comprehensive report should include o Acquisition information (mode, systolic vs. diastolic triggering, contrast volume) o Ascending aorta (position relative to sternum, width 40 mm from annulus) o Descending thoracic and abdominal aorta (tortuosity, atheroma, thrombus, aneurysm) o Iliofemoral arteries (minimal luminal diameter, tortuosity, calcification) o Aortic annulus (short and long diameter, area, circumference) o Aortic valve (number of cusps, degree and location of calcification) o Aortic root (diameter, distance of coronary ostia from aortic annulus) o Presence of LV thrombus 267

Diagnostic Imaging Cardiovascular SELECTED REFERENCES 1. Jilaihawi H et al: Aortic annular sizing for transcatheter aortic valve replacement using cross-sectional 3-dimensional transesophageal echocardiography. J Am Coll Cardiol. 61(9):908-16, 2013 2. Achenbach S et al: SCCT expert consensus document on computed tomography imaging before transcatheter aortic valve implantation (TAVI)/transcatheter aortic valve replacement (TAVR). J Cardiovasc Comput Tomogr. 6(6):366-80, 2012 3. Jilaihawi H et al: Cross-sectional computed tomographic assessment improves accuracy of aortic annular sizing for transcatheter aortic valve replacement and reduces the incidence of paravalvular aortic regurgitation. J Am Coll Cardiol. 59(14):1275-86, 2012 P.4:14

Image Gallery

(Left) Oblique MRA depicts the cross-sectional approach to accurate assessment of the aortic annulus (plane through the red dots) as well as the position of the coronary ostia relative to the annulus . (Right) 3D echocardiogram (TEE) shows the method for measuring the diameter of the aortic annulus . Note the calcified, stenotic aortic valve in short axis . 3D TEE appears to perform better than 2D TEE in the assessment of annulus dimensions.

(Left) CTA of the abdomen and pelvis with volume-rendered images shows the course and caliber of the aorta and its branches. There is a small, suprarenal abdominal aortic aneurysm . (Right) Oblique curved MPR shows the diameter of the right external iliac artery. In this particular case, the minimal diameter of the right external iliac artery was 5 × 6 mm. Given the small caliber of the iliofemoral vessels, the patient underwent TAVR via the transapical approach.

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(Left) Vertical long-axis (2-chamber) coronary CTA shows an apical left ventricular thrombus on a patient being evaluated for TAVR. The presence of an apical thrombus is a relative contraindication to the transapical approach for TAVR. (Right) Axial noncontrast CT of the chest shows circumferential calcification of the ascending aorta . Extensive aortic calcifications (a.k.a. porcelain aorta) increases the risk of surgical AVR and can be the trigger to determine suitability for TAVR. P.4:15

(Left) Intraprocedure transesophageal echocardiogram shows deployment of a 26 mm Edwards SAPIEN valve . Note the catheter extending into the LVOT . (Right) Short-axis TEE image after TAVR shows mild to moderate paravalvular leak on color Doppler. Inaccurate sizing of the aortic annulus and resulting prosthesis mismatch is a risk factor for the development of postoperative aortic insufficiency, which is associated with a worse prognosis.

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(Left) Oblique cardiac CT MPR shows a type A aortic dissection beginning just above the stented valve , which occurred as a complication after TAVR. Note false lumen with partial thrombosis . (Right) Oblique cardiac CT VRT shows the bioprosthetic aortic valve and the ascending aortic dissection . Vascular complications including aortic dissection and iliofemoral dissection are known potential complications of TAVR.

(Left) AP CXR shows a transcatheter aortic valve deployed in the descending thoracic aorta after the valve could not be successfully deployed in the aortic valve position and then could not be withdrawn into the sheath. A second valve was then successfully deployed in the correct position . (Right) Lateral CXR shows a bioprosthetic valve in the descending aorta and in the aortic valve position . The patient tolerated the procedure and in follow-up was well.

Aortic Regurgitation Aortic Regurgitation Gudrun Feuchtner, MD Key Facts Terminology  Incomplete closure of cusps during diastole leading to retrograde blood flow into left ventricle Imaging  Best diagnostic tool: Echocardiography (Doppler regurgitant jet)  MR and CT are alternative modalities Top Differential Diagnoses  Aortic root disease 270

Diagnostic Imaging Cardiovascular  Rheumatic or degenerative/calcific heart disease  Infective endocarditis  Trauma  Bicuspid valve Clinical Issues  Acute aortic regurgitation (AR): Immediate signs of severe left heart failure due to volume overload  Chronic AR: Progressive signs of left heart failure Diagnostic Checklist  Doppler regurgitation jet (echocardiography): Jet length/width, PHT method  Regurgitant flow, fraction, and left ventricular volume (MR)  Incomplete closure of leaflets (CT) and aortic root dimensions  X-ray: Dilated left ventricle  X-ray, CT: Ascending aortic aneurysm/root dilatation frequent  Consider different etiologies of acute and chronic AR  Acute and chronic AR can be distinguished by size of left atrium and left ventricle (radiograph)  Acute: Normal size of left atrium (but often pulmonary edema and severe clinical symptoms)  Chronic: Enlarged left atrium and left ventricle (symptoms late)

(Left) Left sagittal oblique LVOT long-axis view diastolic cardiac CT shows incomplete coaptation of aortic cusps , which results in a diastolic regurgitant orifice, leading to severe aortic insufficiency. (Right) Axial oblique cardiac CT in the plane of diastolic regurgitant orifice (orthogonal to regurgitant jet) shows a bicuspid valve with fusion of right and noncoronary cusps, and central malcoaptation , which can be planimetered (ROI for area measurement) for severity assessment of insufficiency.

(Left) Three-chamber view transesophageal echocardiogram with color Doppler over aortic valve in diastole shows 271

Diagnostic Imaging Cardiovascular diastolic Doppler regurgitation jet originating at the aortic cusp malcoaptation site. Note the aorta and left ventricle . (Right) Aortic valve short-axis cardiac CT shows a tricuspid valve with thickened cusps and central valvular malcoaptation . These findings are consistent with degenerative disease and aortic insufficiency. P.4:17

TERMINOLOGY Abbreviations  Aortic regurgitation (AR) Synonyms  Aortic insufficiency Definitions  Incomplete closure of cusps during diastole leading to retrograde blood flow into left ventricle IMAGING General Features  Best diagnostic clue o Retrograde blood flow into left ventricle by Doppler echocardiography  Acute AR o No left ventricular dilatation o Pulmonary edema due to volume overload  Chronic AR o Eccentric left ventricular hypertrophy and dilatation o Dilatation of ascending aorta and aortic root is common o Valve calcification is uncommon in pure aortic regurgitation Radiographic Findings  Chest radiography o Acute AR  Normal left ventricle size  Pulmonary edema o Chronic AR  Minimal to massive left ventricle enlargement  Normal pulmonary vasculature until chronic severe left ventricular dysfunction and consecutive pulmonary venous hypertension and left atrial enlargement  Dilatation of ascending aorta CT Findings  CTA o Aortic root dilatation ± ascending aortic aneurysm frequent o Measurement of aortic annulus, maximal sinus of Valsalva diameter, sinotubular junction diameters o Evaluation of sinotubular junction effacement  Cardiac gated CTA o Incomplete coaptation of cusps during diastole result in regurgitant orifice (“central valvular leakage” area) o Detects moderate and severe AR, but mild AR can be missed o Cusp morphology: Thickening, calcification, or vegetations o Dilated left ventricle at late stage MR Findings  Diastolic flow void (jet) area in left ventricle on flow-sensitive sequences (cine GRE) provides rough estimation of severity  Ventricle dilatation in severe chronic AR  Gold standard for functional assessment; ejection fraction, ventricular volumes, and myocardial mass  Phase-contrast MR in aortic valve short axis allows for quantification of regurgitant volume Echocardiographic Findings  Echocardiogram o 2D and transesophageal echocardiography o Acute aortic regurgitation  Reduced opening motion and premature closure of valve  Delayed opening of mitral valve  Minimal dilatation of left ventricular cavity with normal function o Chronic aortic regurgitation 272

Diagnostic Imaging Cardiovascular  Marked dilatation of left ventricular cavity with decreased function o Estimation of left ventricular function  M-mode o High-frequency flutter of anterior mitral valve leaflet is indirect sign  Color Doppler o Most sensitive method for assessment of aortic regurgitation: Proximal jet height (“vena contracta”) o Central or eccentric retrograde jet  Continuous-wave Doppler o Measurement of regurgitant jet velocity and calculation of pressure half-time (PHT) Angiographic Findings  Conventional o Left ventriculogram  Regurgitant jet in left ventricle following injection of contrast into aortic root Imaging Recommendations  Best imaging tool o Echocardiography followed by MR  Protocol advice o ECG-gated cardiac CT  Coronary CT angiography examination protocol  Image reconstruction during diastole; oblique sagittal, coronal, and perpendicular axial MPR for detection of incomplete coaptation of cusps DIFFERENTIAL DIAGNOSIS Aortic Root Disease  Dilatation of aortic root (most common cause of pure aortic regurgitation) ± ascending aortic aneurysm o Etiologies: Degenerative/atherosclerotic, cystic medial necrosis, Marfan syndrome, aortitis  Dissection Rheumatic or Degenerative/Calcific Heart Disease  Thickened &/or calcified leaflets prevent closure during diastole  Associated with aortic stenosis and mitral valve disease Infective Endocarditis  Vegetations that prevent coaptation of cusps  Perforation of cusp Trauma  Rupture of sinus of Valsalva  Loss of commissural support producing prolapse  Tear in ascending aorta or dissection P.4:18

Bicuspid Valve  Thickening of leaflets produces incomplete closure &/or prolapse PATHOLOGY General Features  Etiology o Secondary to diseases of aortic valve leaflets &/or wall of aortic root o Acute AR: Infective endocarditis, ascending aortic dissection, trauma o Chronic AR: Aortic root dilatation, rheumatic heart disease, bicuspid valve, very rare syphilis  Valve leaflets o Thickening, shortening, and retraction of 1 or more leaflets o Perforation of valve leaflet or vegetation that prevents coaptation of leaflets o Traumatic destruction of bicuspid aortic valve leaflet  Ascending aorta o Dilatation secondary to degeneration, dissection, hypertension, and infection Staging, Grading, & Classification  3 grades by Doppler echocardiography o Grade I: Mild  Proximal jet height < 3 mm (or < 25% of left ventricular outflow tract [LVOT])  PHT > 500 ms 273

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o

Grade II: Moderate  Proximal jet height = 3-6 mm (or 25-65% of LVOT)  PHT = 200-500 ms Grade III: Severe  Proximal jet height > 6 mm (or > 65% of LVOT)  PHT < 200 ms

CLINICAL ISSUES Presentation  Most common signs/symptoms o Chronic AR is asymptomatic over long period until signs of heart failure develop  Other signs/symptoms o Decrescendo diastolic murmur  Acute AR o Immediate signs of severe left heart failure due to volume overload  Chronic AR o Progressive signs of left heart failure o Infectious endocarditis can exacerbate symptoms Demographics  Age o Variable age manifestation dependent on etiology o Prevalence: 4.9% (Framingham Heart Study [FHS]) o Increasing prevalence with age: 8.5% females and 13% males at 54 years of age (FHS)  Gender o M:F = 3:1 Natural History & Prognosis  Without surgery, patients with symptomatic AR live ˜ 2-4 years  Left ventricular function is important parameter to define clinical management and optimal time point of surgery  If heart failure NYHA III-IV: High mortality with 25% annually Treatment  Acute AR o Intensive medical management to stabilize for aortic valve replacement surgery o 5-year surgical survival rate  85% survival in patients with EF > 45%  50% survival in patients with EF < 45%  Chronic AR o Medical therapy: Antibiotic prophylaxis; vasodilators; calcium antagonists; arrhythmia control o 5-year survival rate: 75% o 10-year survival rate: 50% o Surgical repair before severe left ventricular dysfunction occurs DIAGNOSTIC CHECKLIST Consider  Acute AR and chronic AR can be distinguished by size of left atrium and left ventricle (radiograph) o Acute AR: Normal left atrial size (but often pulmonary edema and severe clinical symptoms) o Chronic AR: Enlarged left atrium and left ventricle (symptoms late)  Echocardiography is primary imaging modality  ECG-gated cardiac CT o Detect moderate and severe AR (usually incidentally on coronary artery study) o Evaluate etiology (ascending aortic aneurysm, dissection, etc.)  Cardiac MR to define best timing of surgery (regurgitant fraction and left ventricular volume measurements) Image Interpretation Pearls  Radiograph: Enlarged ascending aorta and left ventricle  Echocardiography: Retrograde Doppler flow at systole in left ventricle (proximal jet height, PHT method)  ECG-gated cardiac CT: Incomplete coaptation of cusps during diastole  Cardiac MR: Regurgitant fraction, ventricular volumes SELECTED REFERENCES 1. Zeb I et al: Detection of aortic regurgitation with 64-slice multidetector computed tomography (MDCT). Acad Radiol. 17(8):1006-11, 2010 274

Diagnostic Imaging Cardiovascular 2. Alkadhi H et al: Aortic regurgitation: assessment with 64-section CT. Radiology. 245(1):111-21, 2007 3. Jassal DS et al: 64-slice multidetector computed tomography (MDCT) for detection of aortic regurgitation and quantification of severity. Invest Radiol. 42(7):507-12, 2007 4. Feuchtner GM et al: Diagnostic performance of MDCT for detecting aortic valve regurgitation. AJR Am J Roentgenol. 186(6):1676-81, 2006 5. Braunwald E: Valvular heart disease. In Braunwald E: Heart Disease: A Textbook of Cardiovascular Medicine. 6th ed. Philadelphia: W. B. Saunders, 2001 6. Singh JP et al: Prevalence and clinical determinants of mitral, tricuspid, and aortic regurgitation (the Framingham Heart Study). Am J Cardiol. 83(6):897-902, 1999 P.4:19

Image Gallery

(Left) Left ventricular outflow tract (3-chamber) cardiac CT demonstrates marked aortic root and anulus dilatation leading to aortic cusp malcoaptation causing regurgitation . (Right) Axial oblique aortic valve short-axis view in a patient with rheumatic disease shows irregular thickening of the right and adjacent noncoronary cusp margins and incomplete closure of the aortic valve in diastole leading to regurgitation.

(Left) Left ventricular outflow tract (3-chamber) cardiac CT demonstrates large paravalvular contrast collections (pseudoaneurysms) and cusp fenestration and prolapse due to infective endocarditis, causing severe aortic regurgitation (grade III). (Right) Right anterior oblique cardiac CT shows a double-outlet left ventricle after DamusKaye-Stansel surgery with incomplete coaptation of the aortic cusps leading to severe aortic regurgitation .

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(Left) PA radiograph performed prior to surgery shows a tortuous and atherosclerotic aorta and a dilated left ventricle in a patient with known severe aortic regurgitation (grade III). (Right) Coronal oblique MR white blood cine in diastole shows a regurgitant dephasing jet (black) originating from the aortic cusp coaptation site and extending through the left ventricular outflow tract into the left ventricle. The valvular regurgitation in this patient was severe (grade III). (Courtesy R. Cury, MD.)

Bicuspid Aortic Valve Bicuspid Aortic Valve Suhny Abbara, MD, FSCCT Christopher M. Walker, MD Key Facts Terminology  Bicuspid aortic valve (BAV)  Most common congenital cardiovascular malformation  Occurs in 1-2% of world population Imaging  BAV has 2 cusps of generally unequal size  Usually, ridge or raphe lies across 1 cusp Top Differential Diagnoses  Other valve anomalies  Aortic stenosis Pathology  Associations o Congenital left-sided obstructive lesions o Aortic dilation, aneurysms, and dissection o VSD, sinus of Valsalva aneurysm, and coronary artery anomalies  Classification of 3 anatomic characteristics that influence prognosis and treatment o Number of raphes: 0, 1, or 2 o Phenotype: Anteroposterior or right-left opening of valve o Functional status of valve: Quantifies opening and closing (stenosis or regurgitation) Clinical Issues  Symptoms result from development of either valvular stenosis or regurgitation  BAV is predisposed to infective endocarditis  Serial assessment of aortic valve to evaluate chamber dimensions and valvular and ventricular functions  Aortic valve replacement indicated for severe valve dysfunction, symptomatic patients, or abnormal left ventricular dimensions and function

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(Left) Frontal radiograph from a 64-year-old man shows a convex ascending aortic segment consistent with an ascending aortic enlargement . This finding is often seen in aortic valve stenosis although it is nonspecific. (Right) Oblique coronal cardiac CT in the same patient confirms ascending aortic (Ao) aneurysm. Note the thickened aortic valve leaflet , which is suggestive of aortic stenosis.

(Left) Double oblique axial cardiac CT in systole in the same patient shows restricted anteroposterior aortic valve opening and calcification with thickening of bileaflet valve cusps. The valve configuration has been termed a “fish mouth” appearance. (Right) Oblique sagittal MRA in a patient with a congenitally bicuspid aortic valve shows aortic coarctation . Aortic coarctation and pseudocoarctation often are associated with bicuspid aortic valve. P.4:21

TERMINOLOGY Abbreviations  Bicuspid aortic valve (BAV) Definitions  Most common congenital cardiovascular malformation o Occurs in 1-2% of world population o There are 2 functional leaflets, and most have 2 complete commissures  < 50% of cases have fused raphe in middle of 1 leaflet, which may mimic trileaflet valve in diastole  Acquired bicuspid valves are secondary to inflammatory processes (e.g., rheumatic fever) or calcification of normal trileaflet aortic valve IMAGING 277

Diagnostic Imaging Cardiovascular General Features  Best diagnostic clue o Dilated aortic root with systolic doming and diastolic prolapse of 2 aortic cusps o Eccentric closure plane in systole  Size o BAV has 2 cusps of generally unequal size  Ridge or raphe may be seen across 1 cusp  Morphology o Thickened leaflets with either anteroposterior or horizontal (right-left) orientation Imaging Recommendations  Best imaging tool o Echocardiography, MR Radiographic Findings  Characteristic calcification along valve commissures and annulus  Frequently prominent calcified ridge along raphe  Cardiomegaly if BAV is accompanied by significant aortic regurgitation  Ascending aortic enlargement o May have poststenotic ascending aortic aneurysm due to stenotic jet CT Findings  NECT o Allows quantification of aortic valve calcium  Severity of valve calcium correlates with peak and mean aortic valve gradients in cases of stenosis  Cardiac gated CTA o Accurately detects number of valve leaflets, valve motion, and valve calcium on cine CT o Quantifies degree of aortic valve stenosis by systolic valve opening area planimetry (area measurement) o Semiquantitatively grades aortic valve regurgitation by planimetry of anatomic regurgitant orifice in diastole o Allows for evaluation of associated aortic pathology MR Findings  MR cine o Velocity-encoded cine phase-contrast MR quantitates flow  Provides peak systolic flow velocities that can be used to calculate valve gradient across stenosis using modified Bernoulli equation  Provides regurgitant volume and regurgitant fraction in cases of aortic regurgitation  SSFP cine o Detects antegrade spin-dephasing flow void artifact in cases of valve stenosis or retrograde flow void jet across regurgitant orifice o Quantifies left ventricular volume and function, which helps monitor therapy or time surgical intervention  Double IR FSE o Accurate morphological characterization of valve cusps and their orientation (anteroposterior or right-left) o Black blood assessment of thoracic aorta Echocardiographic Findings  BAV shows “doming” configuration in long-axis view when it opens during systole  In short-axis views, opening of 2 leaflets creates “fish mouth” (oval) appearance o Valve may appear normal in diastole because a raphe in larger leaflet may simulate trileaflet valve  Continuous wave Doppler measurements and estimated velocity and gradients in cases of aortic valve stenosis  Color Doppler can be used to grade severity of aortic regurgitation  Transesophageal echocardiogram is useful in defining valve commissures and vegetations Angiographic Findings  2 sinuses of Valsalva with 2 leaflets on anteroposterior 30° right anterior oblique projection  Eccentric systolic jet of contrast with doming and thickening of leaflets with left ventricular injections  Dilated ascending aorta  Aortic regurgitation on aortic root injections 278

Diagnostic Imaging Cardiovascular DIFFERENTIAL DIAGNOSIS Other Valve Anomalies  Unicuspid aortic valve, quadricuspid aortic valve Aortic Stenosis  Senile calcified aortic stenosis, subaortic stenosis, supravalvular stenosis PATHOLOGY General Features  Etiology o Embryologic abnormality in conotruncal channel  Genetics o Abnormal and inadequate production of microfibrillar proteins, such as fibrillin-1 o Abnormal endothelial nitric oxide synthase (eNOS) also implicated o Associated with familial clustering suggesting autosomal dominant inheritance with reduced penetrance  Incidence as high as 10-17% in 1st-degree relatives  Echocardiography is recommended screening tool for offspring and 1st-degree relatives of patients identified as having BAV  Associated abnormalities P.4:22

o

Highly associated with congenital left-sided obstructive lesions  Coarctation of aorta, supravalvular stenosis (Williams syndrome), interrupted aortic arch o BAV is associated with aortic dilation, aneurysms, and dissection  Aortic aneurysm may be due to poststenotic dilation  Aortic root may also have inherent abnormal connective tissue with cystic medial necrosis similar to disorders such as Marfan syndrome  Even after valve replacement for BAV, there is risk of subsequent aortic dissection o Other associated congenital syndromes  Patent ductus arteriosus  Familial aortic dissection  Turner syndrome (30% of patients have BAV) o VSD, sinus of Valsalva aneurysm, and coronary artery anomalies Staging, Grading, & Classification  Classification on 3 anatomic characteristics that influence prognosis and treatment o Number of raphes: 0, 1, or 2 o Phenotype: Anteroposterior or right-left opening of valve o Functional status of valve: Quantifies opening and closing (stenosis or regurgitation) Gross Pathologic & Surgical Features  With aging, valve is predisposed to sclerosis and calcification Microscopic Features  Early in course: Microscopic calcification and lipid deposition in subendothelium and adjacent fibrosa  With disease progression: Marked calcification and occasionally even cartilage deposition CLINICAL ISSUES Presentation  Most common signs/symptoms o Generally asymptomatic  Frequent incidental finding on echocardiography o Symptoms result from development of either valvular stenosis or regurgitation  Other signs/symptoms o BAV is predisposed to infective endocarditis  Lifetime risk of developing infective endocarditis on BAV is 10-30% o Symptoms may also develop secondary to associated aortopathies (i.e., aortic dilation and dissection) Demographics  Age o BAV may be identified in patients of any age  Gender o M:F ≥ 2:1 279

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Epidemiology o BAVs may be present in up to 1-2% of population  Since BAV may be silent through adulthood, incidence is likely underestimated  Incidence is not affected by geography or race Natural History & Prognosis  Aortic valve stenosis is most frequent complication o BAVs are present in majority of patients presenting with aortic stenosis at age 15-65 years o Abnormality in which right and noncoronary cusps are fused is more frequently associated with changes of stenosis or insufficiency in pediatric population o Abnormality in which right and left cusps are fused is less commonly associated with stenosis or insufficiency in children  This arrangement is much more commonly associated with coarctation of aorta and with functionally normal valve  Overall prognosis of BAV is good Treatment  Serial assessment of aortic valve to evaluate valvular function, chamber dimensions, and ventricular function  Modify coronary artery disease risk factors since their presence may accelerate BAV sclerosis and calcification o Treatment of hypercholesterolemia with statin if present  Balloon aortic valvuloplasty is treatment of choice in pediatric cases o Valve repair or replacement becomes necessary later in childhood or adolescence o Ross procedure (pulmonary autograft) is considered in younger patients as alternative to prosthetic valve replacement  Aortic valve replacement is indicated for severe valve dysfunction, symptomatic patients, or abnormal left ventricular dimensions and function  Aortic valve repair may be performed in cases of severe isolated aortic regurgitation  Aortic root replacement is recommended in cases of BAV with aortic dilation of 4-5 cm SELECTED REFERENCES 1. Ko SM et al: Bicuspid aortic valve: spectrum of imaging findings at cardiac MDCT and cardiovascular MRI. AJR Am J Roentgenol. 198(1):89-97, 2012 2. Alkadhi H et al: Cardiac CT for the differentiation of bicuspid and tricuspid aortic valves: comparison with echocardiography and surgery. AJR Am J Roentgenol. 195(4):900-8, 2010 3. Tanaka R et al: Diagnostic value of cardiac CT in the evaluation of bicuspid aortic stenosis: comparison with echocardiography and operative findings. AJR Am J Roentgenol. 195(4):895-9, 2010 4. Ryan R et al: Cardiac valve disease: spectrum of findings on cardiac 64-MDCT. AJR Am J Roentgenol. 190(5):W294303, 2008 5. Lewin MB et al: The bicuspid aortic valve: adverse outcomes from infancy to old age. Circulation. 111(7):832-4, 2005 6. Cripe L et al: Bicuspid aortic valve is heritable. J Am Coll Cardiol. 44(1):138-43, 2004 7. Ward C: Clinical significance of the bicuspid aortic valve. Heart. 83(1):81-5, 2000 8. Arai AE et al: Visualization of aortic valve leaflets using black blood MRI. J Magn Reson Imaging. 10(5):771-7, 1999 9. Beppu S et al: Rapidity of progression of aortic stenosis in patients with congenital bicuspid aortic valves. Am J Cardiol. 71(4):322-7, 1993 P.4:23

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(Left) LVOT SSFP MR in a 25-year-old man shows a spin-dephasing flow void artifact indicating flow acceleration due to aortic stenosis. Note the concentric left ventricular (LV) hypertrophy. LA = left atrium. (Right) Oblique axial SSFP MR image in the same patient shows restricted right-left leaflet opening and a bicuspid aortic valve. Valve planimetry measures the total valve opening area and is a useful adjunct to phase-contrast MR in determining stenosis severity.

(Left) Oblique SSFP MR image shows a bicuspid aortic valve . RV= right ventricle. (Right) Oblique axial phasecontrast MR image in the same patient demonstrates a technique for measuring peak velocity across the stenotic valve. A region of interest (blue outline) is drawn just superior to the aortic valve at peak systole to determine the maximal blood velocity. The maximum velocity is used to determine the pressure gradient across the valve through 2 the modified Bernoulli equation (ΔP = 4v ).

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(Left) Frontal radiograph in a 54-year-old woman with a bicuspid aortic valve and long-standing aortic stenosis shows a marked bulge in the lower right mediastinum caused by an ascending aortic enlargement. (Right) LVOT SSFP MR shows a spin-dephasing flow void artifact of aortic (Ao) regurgitation directed into a dilated left ventricle (LV). The degree of regurgitation was severe as calculated by velocity-encoded cine phase-contrast MR (not shown). LA = left atrium.

Mitral Stenosis Mitral Stenosis Daniel W. Entrikin, MD Key Facts Terminology  Obstruction to left ventricular blood inflow at level of mitral valve Imaging  Acceleration of flow at mitral valve level during left ventricular diastole  Narrowed orifice, often related to commissural &/or chordal fusion  Left atrial dilatation Top Differential Diagnoses  Rheumatic heart disease  Obstruction from tumor (myxoma) or atrial thrombus  Cor triatriatum Clinical Issues  Symptoms appear 20-40 years after acute rheumatic fever in developed countries  Medical therapy to reduce afterload and treat arrhythmias (most common atrial fibrillation)  Frequent atrial fibrillation and associated left atrial thrombus  Anticoagulation is necessary to avoid risk of stroke  Progressive dilatation of left atrium, elevation of left atrial pressures, and eventual right heart failure  Mild mitral valve stenosis may 1st present with symptoms during exercise  Symptoms at rest develop if mitral valve orifice area < 1.5 cm 2 Diagnostic Checklist  Transthoracic echocardiography is primary imaging modality o Increased transvalvular pressure gradient  “Doming” of valve during diastole with “hockey stick” appearance of anterior mitral valve leaflet

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(Left) Posteroanterior radiograph demonstrates cardiomegaly with multiple curvilinear calcifications projecting over the heart, consistent with calcifications of the left atrial wall related to longstanding mitral valve stenosis. (Right) Axial CECT in the same patient demonstrates extensive calcifications of the left atrial wall. Also note the massive dilatation of the left atrium.

(Left) Left ventricular outflow tract (LVOT) or 3-chamber echocardiogram demonstrates “doming” of the MV during diastole with a “hockey stick” appearance of the anterior leaflet in a patient with rheumatic mitral stenosis. LV = left ventricle, LA = left atrium, Ao = aorta. (Right) Diastolic white blood cine MR demonstrates irregular thickening of the anterior mitral valve leaflet with multiple signal voids indicative of calcium. Note the narrowed orifice during diastole. P.4:25

TERMINOLOGY Definitions  Obstruction to left ventricular blood inflow at level of mitral valve (MV) IMAGING General Features  Best diagnostic clue o Acceleration of flow at MV level during left ventricular diastole  Morphology o Thickened &/or calcific leaflets, often with commissural fusion o Chordal thickening &/or fusion o Left atrial dilatation 283

Diagnostic Imaging Cardiovascular Radiographic Findings  Chest radiography o Left atrial enlargement, possible left atrial calcification if longstanding  Right retrocardiac double density o Pulmonary venous hypertension (PVH)  Redistribution/cephalization, interstitial edema (Kerley B lines), etc. o Pulmonary artery (PA), right ventricle, and right atrium enlargement (secondary to left-sided PVH) o If pulmonary arterial hypertension (chronic stage), descending right pulmonary artery diameter ≥ 16 mm CT Findings  NECT o Calcification of MV, mitral annulus, &/or chordae tendinea  Cardiac gated CTA o “Doming” of anterior leaflet during diastolic opening and immobility of posterior leaflet (4D cine imaging) o Narrowing of MV orifice o Thickening &/or calcification of valve leaflets, fusion of chordae tendinea o Left atrial enlargement and left atrial thrombi (hypodense, nonenhancing mass) frequent o Left atrial appendage (LAA) filling defects can cause false-positive findings; delayed images are necessary to confirm thrombus  Normal arterial phase CTA excludes LAA thrombus  NECT and CECT o 8% prevalence of MV calcification by 60 years, about half of which will have evidence of mitral stenosis MR Findings  Diastolic flow dephasing (jet) entering the left ventricle  Left atrial enlargement  Phase contrast can be used to calculate peak systolic velocity and gradients Echocardiographic Findings  Echocardiogram o Transthoracic echocardiography (TTE)  Fusion of leaflets with poor leaflet separation in diastole  Left atrial enlargement  “Doming” of anterior MV leaflet o Transesophageal echocardiography (TEE)  4D images demonstrate commissural fusion and reduced orifice area  TEE better visualizes left atrial/appendage thrombus (compared with TTE)  Color Doppler o Increased transvalvular pressure gradient as estimated by modified Bernoulli equation o MV orifice area (by either continuity equation or pressure half-time [PHT] method)  PHT method may be inaccurate in setting of left ventricular diastolic dysfunction o High-velocity flow jet in left ventricle Angiographic Findings  Conventional o Determines wedge pressure and indicates degrees of pulmonary hypertension, mitral stenosis, and regurgitation Imaging Recommendations  Best imaging tool o Echocardiography  Transthoracic as baseline examination  Transesophageal to clarify etiology, before surgery, and to rule out left atrial or LAA thrombi  Protocol advice o ECG-gated cardiac CT  Multiphase image reconstruction with multiplanar reformations (MPR): 2-chamber, 3chamber, 4-chamber, and short-axis views  4D cine imaging DIFFERENTIAL DIAGNOSIS Rheumatic Heart Disease 284

Diagnostic Imaging Cardiovascular  Causes thickening and calcification of MV apparatus, typically resulting in commissural &/or chordal fusion  Diastolic doming of MV results in “hockey stick” appearance of anterior leaflet during diastole Obstruction of Mitral Valve  Atrial myxoma obstructing valve orifice (e.g., by diastolic prolapse)  Vegetations from infective endocarditis obstructing MV  Ball-valve thrombus in left atrium Other Causes: Rare  Congenital mitral stenosis (e.g., parachute MV)  Malignant carcinoid, rhabdomyosarcoma  Mucopolysaccharidoses, including Hunter-Hurler, Whipple, and Fabry diseases  Papillary fibroelastoma PATHOLOGY General Features  Etiology o Rheumatic heart disease is predominant cause (> 95%)  Associated abnormalities o Pulmonary arterial hypertension, elevated right-sided pressures, and tricuspid regurgitation  Rheumatic heart disease o Thickening, fusion, and, finally, calcification of mitral leaflets, mitral annulus, and proximal chordae tendineae P.4:26

Staging, Grading, & Classification  Mild, moderate, severe (grades I-III) by echocardiography o Mild (grade I): MV orifice area > 1.5 cm 2; valvular pressure gradient < 5 mm Hg; PA systolic pressure < 30 mm Hg o Moderate (grade II): MV orifice area 1.0-1.5 cm2; valvular pressure gradient 5-10 mm Hg; PA systolic pressure 30-50 mm Hg o Severe (grade III): MV orifice area < 1.0 cm 2; valvular pressure gradient > 10 mm Hg; PA systolic pressure > 50 mm Hg Gross Pathologic & Surgical Features  Thickening and fusion of MV apparatus o Commissure thickening in 30% o Cusps thickening in 15% o Chordae in 10% o Combination of lesions in 45%  MV apparatus has funnel-shaped appearance related to commissural and chordal fusion  Thickened, adherent leaflets inhibit opening and closing of valve  Calcium deposits in leaflets and occasional in annulus Microscopic Features  Fibrotic and calcific depositions in thickened leaflets CLINICAL ISSUES Presentation  Most common signs/symptoms o Dyspnea  Clinical profile o Mild MV stenosis may 1st present with symptoms during exercise o Symptoms at rest develop if MV orifice area < 1.5 cm2  Exertional dyspnea frequently accompanied by cough and wheezing  Stress-induced pulmonary edema (pregnancy)  Progressive dilatation of left atrium, elevation of left atrial pressures, and eventual right heart failure  Chest pain simulating coronary artery disease in 15% of patients  Frequent atrial fibrillation results in increased risk of thrombus o Left atrial thrombi  Up to 30% in severe mitral stenosis and atrial fibrillation  Anticoagulation is necessary to avoid risk of stroke Demographics 285

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Age

o Mean age of clinical presentation: 50-70 years Gender o F:M = 2:1  Epidemiology o Prevalence: 1.6% of females and 0.4% of males Natural History & Prognosis  Symptoms appear 20-40 years after acute rheumatic fever in developed countries  Severe disability (New York Heart Association class II) 5-10 years after initial symptoms  10-year survival rate without surgery is 50-60% if asymptomatic at time of diagnosis o 10-year survival rate without surgery is < 15% if presenting with severe clinical symptoms  Mortality caused by progressive pulmonary and systemic congestion (60-70%) or pulmonary embolism (10%) Treatment  Medical therapy to reduce afterload and treat arrhythmias (most common atrial fibrillation)  Percutaneous balloon mitral valvuloplasty with mortality rate of 1-2% but relative high recurrence requiring surgery  Surgical valvotomy with mortality rate of 1-3% and 5-year survival rate > 90%  MV replacement with mortality rate of 3-8% DIAGNOSTIC CHECKLIST Consider  TTE is primary imaging modality (increased transvalvular pressure gradient)  TEE is standard to rule out LAA thrombi in atrial fibrillation o Recent studies demonstrate planimetry by TEE to be comparable to other measures of severity o 3D TEE useful to identify commissural fusion  ECG-gated cardiac CT and cardiac MR useful o Clarify etiology of nonprimary valvular mitral stenosis (obstruction by myxoma, thrombus, etc.) o 4D volume renderings demonstrate commissural and chordal fusions o Planimetry comparable to other measures of mitral stenosis severity Image Interpretation Pearls  “Doming” of valve during diastole with “hockey stick” appearance of anterior MV leaflet  Irregularly thickened leaflets with narrowing of orifice area typical for rheumatic disease  Enlargement of left atrium SELECTED REFERENCES 1. Sanati HR et al: Percutaneous mitral valvuloplasty using echocardiographic intercommissural diameter as reference for balloon sizing: a randomized controlled trial. Clin Cardiol. 35(12):749-54, 2012 2. Schlosshan D et al: Real-time 3D transesophageal echocardiography for the evaluation of rheumatic mitral stenosis. JACC Cardiovasc Imaging. 4(6):580-8, 2011 3. Bonow RO et al: ACC/AHA 2006 guidelines for the management of patients with valvular heart disease. Circulation. 2006 Aug 1;114(5):e84-231. Review. Erratum in: Circulation. 2007 Apr 17;115(15):e409. Circulation. 121(23):e443, 2010 4. Mahnken AH et al: MDCT detection of mitral valve calcification: prevalence and clinical relevance compared with echocardiography. AJR Am J Roentgenol. 188(5):1264-9, 2007 5. Messika-Zeitoun D et al: Assessment of the mitral valve area in patients with mitral stenosis by multislice computed tomography. J Am Coll Cardiol. 48(2):411-3, 2006 6. Movahed MR et al: Increased prevalence of mitral stenosis in women. J Am Soc Echocardiogr. 19(7):911-3, 2006 P.4:27 

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(Left) Short-axis 4D volume-rendered CT image of a mitral valve (view from within the left ventricle) demonstrates commissural fusion resulting in narrowed orifice during diastole. (Right) Similar volume rendering through the left ventricular outflow tract demonstrates thickened and fused chordae extending from the papillary muscles to both the anterior leaflet (chordae ) and posterior leaflet (chordae ) of the mitral valve.

(Left) Short-axis thick slab 4D volume-rendered CT image of the mitral valve of the same patient (view from within the left atrium) demonstrates commissural fusion and narrowing of the mitral orifice during diastole. (Right) Taken from the left atrium perspective, intraoperative photograph of the mitral valve in the same patient shows the narrow mitral valve commissural fusion resulting in a narrowed mitral orifice.

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(Left) Thin-slab 4D volume-rendered CT image in a 3-chamber plane demonstrates a large invasive left atrial sarcoma resulting in narrowing of the left atrial cavity, irregular thickening of the MV leaflets , and stenosis of the MV orifice . (Right) T2-weighted dark blood 4-chamber cardiac MR in a different patient shows a large hyperintense mass arising from the interatrial septum and prolapsing through the mitral orifice during diastole, resulting in a functional mitral stenosis.

Mitral Valve Prolapse Mitral Valve Prolapse Daniel W. Entrikin, MD Key Facts Terminology  Mitral valve prolapse: Systolic extension of mitral valve leaflets > 2 mm into left atrium o “Billowing” leaflet: Entire leaflet or portion of leaflet bows posteriorly into left atrium > 2 mm beyond mitral annular plane o “Flail” leaflet: Chordal rupture to portion of leaflet allows retrograde extension of free edge of leaflet into left atrium  Myxomatous mitral valve disease: Inflammatory and infiltrative disease of mitral valve that involves excess collagen and proteoglycan deposition in valve tissue o Results in edematous leaflet thickening, elongation, redundancy, and dysfunction Imaging  May relate to problem with mitral valve or subvalvular apparatus (chordae tendineae and papillary muscles)  Important to localize abnormality based on Carpentier classification o Anterior leaflet divided into 3 segments: A1, A2, A3 o Posterior leaflet divided into 3 scallops: P1, P2, P3  Echocardiography o Transesophageal echo is gold standard for accurately localizing problem by Carpentier classification scheme  Cardiac MR and ECG-gated cardiac CT o May be useful second-line imaging modalities if echocardiography is inconclusive Top Differential Diagnoses  Myxomatous mitral valve disease  Hereditary connective tissue disease  Infectious endocarditis  Rheumatic disease  Trauma

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(Left) Three-chamber view graphic shows billowing of mitral valve leaflets posterior to the plane of the mitral annulus . (Right) Volume-rendered 3-chamber view cardiac CT image in a patient with a normal mitral valve demonstrates no extension of valve leaflets posterior to the plane of the mitral annulus .

(Left) Three-chamber view multiplanar reformat (MPR) cardiac CT demonstrates billowing of the anterior and posterior leaflets posterior to the mitral annulus plane (white line). (Right) Volume-rendered 3-chamber view cardiac CT image in a patient with prolapse also demonstrates mild billowing of both the anterior and posterior leaflets of the mitral valve posterior to the plane of the mitral annulus . P.4:29

TERMINOLOGY Abbreviations  Mitral valve prolapse (MVP) Definitions  Mitral valve prolapse: Systolic extension of mitral valve leaflets > 2 mm into left atrium o 2 main forms  “Billowing” leaflet: Entire leaflet or portion of leaflet bows posteriorly into left atrium > 2 mm beyond mitral annular plane  “Flail” leaflet: Chordal rupture to portion of leaflet allows retrograde extension of free edge of leaflet into left atrium  Mitral regurgitation: Systolic retrograde flow of blood from left ventricle into left atrium  Myxomatous mitral valve disease: Inflammatory and infiltrative disease of mitral valve o Involves excess collagen and proteoglycan deposition in valve tissue o Results in edematous leaflet thickening, elongation, redundancy, and dysfunction 289

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Most common cause of mitral prolapse and regurgitation requiring surgery in Western world a.k.a. Barlow syndrome or floppy valve disease

IMAGING General Features  Best diagnostic clue o Systolic extension of mitral valve leaflets into left atrium > 2 mm o If chordal rupture is present and free edge prolapses significantly into left atrium, “flail” portion of leaflet is present  Location o May relate to problem with mitral valve or subvalvular apparatus (i.e., chordae tendineae or papillary muscles) o Important to localize abnormality based on Carpentier classification  Anterior leaflet divided into 3 segments: A1, A2, and A3  Posterior leaflet divided into 3 scallops: P1, P2, and P3  Morphology o With myxomatous mitral valve disease, there is diffuse thickening of mitral valve leaflets, which become elongated and redundant and eventually prolapse Radiographic Findings  Chest radiography o Most commonly normal o May show left ventricular and left atrial dilatation if mitral prolapse is associated with significant mitral regurgitation CT Findings  NECT o May show left ventricular and left atrial dilatation if mitral prolapse is associated with significant mitral regurgitation  CECT o With myxomatous mitral valve disease, diffuse thickening of mitral valve leaflets may be evident even on non-gated CT examinations  Cardiac gated CTA o Thickened mitral valve leaflets with systolic “bowing” > 2 mm into left atrium beyond mitral annular plane during systole o Incomplete closure of leaflets during ventricular systole if insufficiency Echocardiographic Findings  Echocardiogram o 2D echocardiography  Thickening (3-5 mm) of 1 or both valve leaflets  Symmetrical bowing of valve leaflets > 2 mm behind plane of annulus  Asymmetrical buckling of free edge of 1 or both leaflets into left atrium when chordae have ruptured (“flail” leaflet) o Transesophageal echocardiography  Detailed anatomy of mitral valve and chordae  Color Doppler o Eccentric systolic high-velocity flow jet of mitral regurgitation Angiographic Findings  Conventional o Buckling of mitral valve o Scalloped valve edges reflecting redundant valve tissue o Retrograde systolic flow jet if mitral regurgitation Imaging Recommendations  Best imaging tool o Echocardiography  Protocol advice o Echocardiography  Transthoracic echo may demonstrate findings and can readily recognize associated regurgitation  Transesophageal echo is gold standard for accurately localizing problem by Carpentier classification scheme and determining repairability o ECG-gated cardiac CT 290

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May be useful 2nd-line imaging modality if echo is inconclusive Retrospective gating and multiphase reconstructions necessary to allow dynamic assessment 4D cine imaging; multiplanar reformations (MPR) (3-chamber, 2-chamber, and 4-chamber views)

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Cardiac MR o Cine white blood images in 3-chamber view (allows adequate evaluation for A2/P2 prolapse only)  Additional planes may be required to evaluate A1/P1 and A3/P3 portions of valve MR Findings  MR cine o Same criteria used in echocardiography: Symmetrical bowing of valve leaflets > 2 mm behind plane of annulus o Coexistent mitral regurgitation as eccentric retrograde systolic flow jet  Phase-contrast MR o Detect and quantify mitral regurgitation o Plane needs to be perpendicular to mitral valve regurgitant orifice P.4:30

DIFFERENTIAL DIAGNOSIS Myxomatous Mitral Valve Disease  Also referred to as Barlow syndrome, floppy valve disease, and mitral valve prolapse syndrome  Most common cause of mitral valve prolapse in Western world  Excess collagen and proteoglycan deposition in valve tissue results in edematous leaflet thickening, elongation, redundancy, and dysfunction (i.e., prolapse or flail leaflets) Hereditary Connective Tissue Disease  Marfan syndrome  Ehlers-Danlos syndrome  Osteogenesis imperfecta Infectious Endocarditis  Prolapse of perforated leaflets, free leaflet margins, or vegetations (mimicking leaflet prolapse) Rheumatic Disease; Trauma  Diseased subvalvular apparatus (e.g., ruptured chordae) mostly leading to “flail” leaflet PATHOLOGY General Features  Etiology o Primary (familial or nonfamilial) or secondary o Condition may be inherited, especially in association with connective tissue disorders such as Marfan syndrome Gross Pathologic & Surgical Features  Edematous, thickened, elongated, and redundant mitral valve leaflets in myxomatous mitral valve disease  If advanced disease is present, chordal thinning and rupture may be present (results in “flail” portion of leaflet) Microscopic Features  Myxomatous mitral valve disease o Inflammatory cell and fibroblast infiltration of leaflets o Disarray of collagen/elastin and excess deposition of proteoglycans CLINICAL ISSUES Presentation  Most common signs/symptoms o Most patients are asymptomatic (60%) or experience syncope, palpitations, or atypical chest pain o Atrial fibrillation due to progressive left atrial enlargement o Symptoms of heart failure develop in presence of concomitant chronic mitral regurgitation and decreasing cardiac function o Irregular heartbeat or palpitations, especially while lying on left side o May be associated with numerous symptoms of dysautonomia including  Anxiety, panic attacks, headaches, fatigue, depression  Other signs/symptoms 291

Diagnostic Imaging Cardiovascular o Systolic “click” ± murmur Clinical profile o Strong hereditary component for MVP o Present in 90% of Marfan syndrome cases or if 1st-degree relative is affected o Sudden cardiac death < 2% (most likely ventricular tachyarrhythmia), more frequent in familial form o Fibrin emboli and increased risk of cerebrovascular accidents in patients < 45 years of age Demographics  Age o Manifestation usually between 20-40 years of age  Gender o F:M = 2:1  Epidemiology o Most prevalent cardiac valvular abnormalities affecting 2-5% of population Natural History & Prognosis  Spectrum ranges from normal life to severe mitral regurgitation requiring surgery  At risk for development of endocarditis, arrhythmias, and spontaneous rupture of chordae Treatment  Most patients with mitral valve prolapse require no specific precautions DIAGNOSTIC CHECKLIST Consider  Echocardiography is primary imaging modality Image Interpretation Pearls  Localization to A1, A2, and A3 or P1, P2, and P3 aids in surgical planning SELECTED REFERENCES 1. Guy TS et al: Mitral valve prolapse. Annu Rev Med. 63:277-92, 2012 2. Grau JB et al: The genetics of mitral valve prolapse. Clin Genet. 72(4):288-95, 2007 3. Hepner AD et al: The prevalence of mitral valve prolapse in patients undergoing echocardiography for clinical reason. Int J Cardiol. 2007 4. Pinheiro AC et al: Diagnostic value of color flow mapping and Doppler echocardiography in the quantification of mitral regurgitation in patients with mitral valve prolapse or rheumatic heart disease. J Am Soc Echocardiogr. 20(10):1141-8, 2007 5. Sharma R et al: The evaluation of real-time 3-dimensional transthoracic echocardiography for the preoperative functional assessment of patients with mitral valve prolapse: a comparison with 2-dimensional transesophageal echocardiography. J Am Soc Echocardiogr. 20(8):934-40, 2007 6. Mechleb BK et al: Mitral valve prolapse: relationship of echocardiography characteristics to natural history. Echocardiography. 23(5):434-7, 2006 7. Müller S et al: Comparison of three-dimensional imaging to transesophageal echocardiography for preoperative evaluation in mitral valve prolapse. Am J Cardiol. 98(2):243-8, 2006 8. Pepi M et al: Head-to-head comparison of two- and three-dimensional transthoracic and transesophageal echocardiography in the localization of mitral valve prolapse. J Am Coll Cardiol. 48(12):2524-30, 2006 P.4:31 

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(Left) Systolic MPR 3-chamber view cardiac CT image in a patient with myxomatous mitral valve disease demonstrates marked thickening of both the anterior and posterior leaflets of the mitral valve. The tip of the P2 scallop of the posterior leaflet is posterior to the anterior leaflet and behind the plane of the mitral annulus , indicative of a flail P2 scallop. (Right) TEE image of the same patient demonstrates a large eccentric regurgitant jet into the left atrium.

(Left) Volume-rendered short-axis cardiac CT image of myxomatous mitral valve viewed from left atrial perspective demonstrates marked thickening and redundancy of all portions of mitral valve leaflets. (Right) Systolic phase volumerendered 3-chamber view from cardiac CT patient with mild myxomatous mitral valve disease demonstrates severely flail P2 scallop of the posterior leaflet resulting in a large region of malcoaptation .

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(Left) Systolic phase 4-chamber view from cardiac CT demonstrates a flail P1 scallop of the posterior leaflet of the mitral valve. Note how the free edge of the P1 scallop is severely posteriorly displaced relative to the plane of the mitral annulus , resulting in a large area of malcoaptation . (Right) Systolic phase 4-chamber view transesophageal echocardiogram with Doppler in the same patient demonstrates a large eccentric regurgitant jet into the left atrium.

Mitral Regurgitation Mitral Regurgitation Daniel W. Entrikin, MD Key Facts Terminology  Mitral regurgitation (MR)  Incomplete closure of mitral valve during systole resulting in retrograde blood flow into left atrium (LA) Imaging  Retrograde flow from left ventricle (LV) into LA during systole  Acute MR: Usually normal heart size, often with asymmetric pulmonary edema (most severe in right upper lobe)  Chronic MR: Dilated LA and LV; pulmonary artery and right heart dilatation late in disease Top Differential Diagnoses  Degenerative mitral valve disease (60-70%)  Ischemic MR (20%)  Infective endocarditis (2-5%)  Rheumatic heart disease (2-5%)  Miscellaneous: Systolic anterior motion, cardiomyopathies, inflammatory diseases (e.g., collagen vascular), traumatic injuries, congenital diseases Pathology  Classified based on causes (ischemic vs. nonischemic) and mechanisms (functional vs.organic)  Graded by echocardiography based on size of vena contracta, regurgitant volume, regurgitant fraction, and effective regurgitant orifice area Diagnostic Checklist  Because of reduced afterload, systolic function may appear in normal range even in severe disease o Ejection fraction < 60% often indicates need for surgery  Increased LV diameter (> 40 mm) at end-systole also indicates high risk and need for surgery

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(Left) AP radiograph at the time of presentation shows extensive right lung airspace consolidation, which is most severe in the right upper lobe . In the left lung there is only mild perihilar interstitial prominence and subtle perihilar airspace consolidation . (Right) Systolic white blood cine image from cardiac MR in the same patient demonstrates severe eccentric mitral regurgitation directed toward the right superior pulmonary vein, which explains the asymmetric pulmonary edema by chest x-ray.

(Left) PA radiograph show an enlarged left atrium with a double-density sign and splaying of the carina . There is also left ventricular (LV) dilatation. Notice that the right atrial contour is normal in size. (Right) Lateral radiograph of the same patient demonstrates posterior displacement of the left atrial contour and left lower lobe bronchus , consistent with left atrial dilatation. Notice the clear retrosternal space indicative of normal right ventricular size. P.4:33

TERMINOLOGY Abbreviations  Mitral regurgitation (MR) Synonyms  Mitral insufficiency Definitions  MR: Incomplete closure of mitral valve (MV) during systole resulting in retrograde blood flow into left atrium (LA)  Mitral valve prolapse (MVP): Systolic movement of valve leaflet into LA > 2 mm beyond annulus  Flail leaflet: Eversion of mitral valve leaflet tip into LA o Usually caused by ruptured chordae 295

Diagnostic Imaging Cardiovascular IMAGING Radiographic Findings  Radiography o Acute MR: Usually normal heart size, often with asymmetric pulmonary edema (most severe in right upper lobe) o Chronic MR  Dilated left ventricle (LV)  Dilated LA: Double density and carinal splaying  Late: Pulmonary hypertension (dilated pulmonary arteries) and right heart dilatation (right ventricle filling retrosternal clear space) CT Findings  Cardiac gated CTA o Multiphase studies show similar morphologic findings as echocardiography and MR  Limited by lack of ability to assess flow  Volumetric assessment of LA (at end systole) is useful in predicting risk of atrial fibrillation MR Findings  Systolic flow dephasing (jet) into LA  Gold standard for functional assessment; LV ejection fraction, LV volumes, and LV mass o LA and LV dilatation is common in chronic MR  Phase contrast may be used to quantitate severity Echocardiographic Findings  Doppler echocardiography o Combined evaluation with color, pulsed-wave, and continuous-wave Doppler is utilized  Quantitative 2D echocardiography o Useful for estimation of LV and LA volumes  3D echocardiography o Still investigational but showing promise in evaluation of annular size and localization of MV dysfunction in setting of prolapse/flail leaflets Angiographic Findings  Not commonly used: Prompt appearance of contrast in LA following LV injection Imaging Recommendations  Best imaging tool o Echocardiography is most commonly utilized for diagnosis and surveillance imaging DIFFERENTIAL DIAGNOSIS Degenerative Mitral Valve Disease (60-70%)  Myxomatous degeneration: a.k.a. Barlow syndrome o Elongated, redundant, and thickened leaflets secondary to mucopolysaccharide deposition o Often results in MVP or flail leaflet  Primary flail leaflets o Usually a result of ruptured chordae o Posterior leaflet involved in 70% of case  Annular calcification: May distort or enlarge over time Ischemic MR (20%)  Ventricular remodeling results in functional MR o LV remodeling and dilatation → apical displacement of papillary muscles → traction on MV via chordae → incomplete coaptation (despite normal MV leaflets) o Malcoaptation from annular flattening and dilatation  Papillary muscle rupture o Rare, but can be a cause for severe acute MR Infective Endocarditis (2-5%)  Perforation of leaflets  Vegetations may prevent complete leaflet coaptation Rheumatic Heart Disease (2-5%)  Thick (and often calcified), stiff leaflets and chordae, often with chordal and commissural fusion Miscellaneous  Septal hypertrophy causing systolic anterior motion of anterior MV leaflet, cardiomyopathies, inflammatory diseases (e.g., collagen vascular) PATHOLOGY 296

Diagnostic Imaging Cardiovascular General Features  Genetics o Some genetic causes: Familial MVP, Marfan syndrome, and other connective tissue diseases Staging, Grading, & Classification  Broken into causes and mechanisms o Causes: Ischemic vs. nonischemic o Mechanisms: Functional (i.e., valve is structurally normal but dysfunctional, typically because of ventricular remodeling) vs. organic (i.e., intrinsic abnormality of MV apparatus)  Graded by echo based on size of vena contracta (VC), regurgitant volume (RVol), regurgitant fraction (RF), and effective regurgitant orifice (ERO) area o Mild: VC 1-3 mm, RVol < 30 mL, RF < 30%, ERO < 0.2 cm2 o Moderate: VC 4-6 mm, RVol 30-59 mL, RF 30-49%, ERO 0.2-0.39 cm2 o Severe: VC ≥ 7 mm, RVol ≥ 60 mL, RF ≥ 50%, ERO ≥ 0.4 cm2  Severity is graded more stringently in individuals with ischemic MR  Severe disease at lower threshold  Severe ischemic MR: RVol > 45 mL, RF > 40%, ERO > 0.3 cm2  Taken in context of clinical presentation and with respect to LV size and function P.4:34

o o

Because of reduced afterload, LV function may be artificially preserved Volume overload eventually results in increased LV end-diastolic diameter (LV-EDD) and progressively compromises LV systolic function  LV systolic dysfunction is indicated by LV end-systolic diameter (LV-ESD) > 40 mm

CLINICAL ISSUES Presentation  Most common signs/symptoms o Acute MR (uncommon)  Almost always severe symptoms  LA is normal in size with increase in pressure leading to pulmonary edema  Reduced forward output (shock) may develop due to LV volume overload o Chronic MR (most common)  May be asymptomatic until late in course of disease  Risk of morbidity and mortality depends not only on severity of disease but also on the underlying causes and mechanisms  In general with severe chronic MR, > 90% of patients either die or require surgery within 10 years  Other signs/symptoms o Atrial fibrillation (AFib)  Common consequence of chronic MR  Associated with increased LA volumes 2  LA volume > 40 mL/m is predictive of AFib  Necessitates chronic anticoagulation to avoid LA thrombus and risk for systemic embolization Demographics  Age o Typically older individuals in industrialized nations o Younger patients in countries with endemic rheumatic fever  Epidemiology o Moderate to severe MR is most common valve disease in United States o Prevalence increases with age  In countries with endemic rheumatic fever, there is increased prevalence in younger patients Treatment  Medical management: Varies according to mechanism of disease (organic or functional) o Organic disease  Endocarditis: Antibiotics utilized to prevent valvular and perivalvular complications  Medical management otherwise has shown little efficacy in management of chronic organic MR 297

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1 notable exception is that of anticoagulation in setting of AFib related to chronic MR o Functional disease  Medical therapy is similar to typical heart failure regimens and is typically based on longacting β-blocker (e.g., carvedilol) and ACE-inhibition  Surgical management o Only approach shown to provide sustained relief of symptoms of heart failure o Performed via sternotomy, hemisternotomy, or minimally invasive thoracoscopic approach o May involve valve repair (usually preferred) or valve replacement, ± annuloplasty  MV repair  May involve valvular, subvalvular, &/or annular procedures to restore leaflet coaptation  More successful with redundant leaflets (e.g., Barlow disease) than retracted (e.g., rheumatic disease) leaflets  Prolapse/flail repair typically involves resection of redundant portion of leaflet in conjunction with chordal transfer, chordal shortening, or placement of artificial chords  MV replacement  Bioprosthetic: Less durable but does not require anticoagulation; typically utilized in older individuals (> 65 years)  Mechanical: More durable but requires chronic anticoagulation; typically used in younger individuals  Choice is also influenced by patient preference and ability to maintain anticoagulation  Either approach must aim to preserve integrity and function of mitral subvalvular apparatus  Interventional management (still investigational) o Mitral clip: Utilized to create permanent coaptation between anterior and posterior leaflets o Coronary sinus cinching: Potential substitution for annuloplasty DIAGNOSTIC CHECKLIST Image Interpretation Pearls  Grading is typically based on echocardiography  LA volume is predictive of AFib and need for anticoagulation  Because of reduced afterload, systolic function may appear in normal range even in severe disease o Ejection fraction < 60% often indicates need for surgery  Increased LV size at end-systole (LV-ESD > 40 mm) also indicates high risk and need for surgery  Regardless of imaging modality used, try to differentiate between ischemic and nonischemic etiologies, as well as functional versus organic causes of MR, as this may significantly affect management SELECTED REFERENCES 1. ACC/AHA et al: ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 114(5):e84-231; 2006. Review. Erratum in: Circulation. 115(15):e409, 2007. Circulation. 121(23):e443, 2010 2. Enriquez-Sarano M et al: Mitral regurgitation. Lancet. 373(9672):1382-94, 2009 3. Alkadhi H et al: Mitral regurgitation: quantification with 16-detector row CT—initial experience. Radiology. 238(2):454-63, 2006 4. Boudoulas H et al: Mitral valvular regurgitation : etiology, pathophysiologic mechanisms, clinical manifestations. Herz. 31(1):6-13, 2006 5. Westenberg JJ et al: Accurate quantitation of regurgitant volume with MRI in patients selected for mitral valve repair. Eur J Cardiothorac Surg. 27(3):462-6; discussion 467, 2005 P.4:35

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(Left) White blood 3-chamber view in early systole shows LV dilatation and a centrally oriented jet . The tethering of valve leaflets to the dilated LV wall resulted in failure of coaptation (functional mitral regurgitation). (Right) White blood 3-chamber view in a patient with septal hypertrophy shows an eccentric mitral regurgitation jet into the left atrium related to systolic anterior motion of anterior mitral valve leaflet . Note presence of systolic jet in LV outflow tract below the aortic valve.

(Left) Thick-slab short-axis volume-rendered cardiac gated CTA image at the level of the mitral valve in systole (valve closed) demonstrates an 8 mm perforation in the anterior leaflet. (Right) MPR from the same examination (left) and intraoperative transesophageal echocardiogram (right) oriented through the anterior leaflet of the mitral valve (in both) show discontinuity at the site of perforation on the MPR and eccentric mitral regurgitation into the left atrium on the echo .

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(Left) Thin-slab volume-rendered 3-chamber view from a cardiac gated CTA during systole demonstrates a flail P2 scallop of the posterior leaflet of the mitral valve resulting in a large area of incomplete coaptation . (Right) Thick-slab short-axis volume-rendered image during systole (same patient), looking at the mitral orifice from the left atrial perspective, also demonstrates the flail P2 scallop and the resultant region of incomplete coaptation .

Mitral Annular Calcification Mitral Annular Calcification Suhny Abbara, MD, FSCCT Key Facts Imaging  J-, C-, U-, or O-shaped mitral annular calcification (MAC) on radiography or reconstructed CT  “Eggshell” or rim-calcified mass in same location containing lower density material (toothpaste-like necrotized calcium)  NECT is usually sufficient for diagnosis  Cardiac CTA may be useful for presurgical planning to assess myocardial involvement, distinguish whether leaflets are calcified or not, and distinguish caseous calcification from tumor  Hyperechogenic, dense calcification with acoustic shadowing  Echodense mass with echolucent center (liquefaction necrosis)  May mimic neoplasm on echocardiography  Calcium is usually dark on all MR pulse sequences o Helpful for differential diagnosis of caseous calcification vs. neoplasm Top Differential Diagnoses  MAC may be a pitfall on calcium scoring CT as MAC can mimic atherosclerotic calcification in left circumflex coronary artery Pathology  In patients with end-stage renal disease, ENPP1 genotype is associated with higher severity of systemic arterial calcification  Not usually associated with mitral valve stenosis or regurgitation  If extensive calcification, myocardium may be involved  Caseous calcification: Toothpaste-like, white material = liquefaction necrosis

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(Left) LV long-axis view SSFP image shows a mass lesion wedged into the inferior left atriventricular (AV) groove, slightly hypointense to myocardium. Note a very thin hypointense rim. Caseous MAC may be difficult to differentiate from a neoplasm or aneurysm on MR and echocardiography. (Courtesy W. Eicher, MD.) (Right) LV long-axis view T1WI post Gd (same patient) shows no enhancement of the AV groove mass . Note the thin hypointense rim corresponding to calcification seen on CT. (Courtesy W. Eicher, MD.)

(Left) LV long-axis view cardiac CT in the same patient shows a hyperdense (compared to myocardium) lesion in the left atriventricular groove that displays rim or “eggshell” calcification , which is characteristic of caseous MAC. (Courtesy W. Eicher, MD.) (Right) Axial nonenhanced cardiac gated CT in the same patient shows that the content of the rim calcified lesion is also of high-density material , consistent with liquified caseous mitral annular calcification. (Courtesy W. Eicher, MD.) P.4:37

TERMINOLOGY Abbreviations  Mitral annular calcification (MAC) Synonyms  Annular mitral valve calcification Definitions  Chronic degenerative calcification of fibrous mitral valve annulus  May develop caseous necrosis IMAGING General Features 301

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Best diagnostic clue o J-, C-, U-, or O-shaped MAC o “Eggshell” or rim-calcified mass in same location containing lower density material (toothpaste-like necrotized calcium)  Location o Posterior base (early stage) and full annulus (late stage)  Morphology o Dense calcification  Rare variant: Caseous calcification (due to liquefaction necrosis) Imaging Recommendations  Best imaging tool o Radiograph (lateral views) o Computed tomography o Echocardiography  Protocol advice o CT  NECT is usually sufficient for diagnosis  Contrast-enhanced cardiac ECG-gated CT may demonstrate relationship to surrounding structures (e.g., left circumflex coronary artery)  Cardiac CT may be useful for presurgical planning to assess myocardial involvement, distinguish whether leaflets are calcified or not, and distinguish caseous calcification from tumor o Transthoracic echocardiography  B-mode, M-mode, and Doppler Radiographic Findings  Incomplete calcification of posterior annulus (forming J-, C-, or U-shaped MAC)  Entire annulus calcified (O-shaped) in late cases o Best seen on lateral projections CT Findings  NECT o Dense calcification within unenhanced cardiac tissue along expected location of posterior or entire annulus o Sparing of mitral valve leaflets o May protrude into lumen Echocardiographic Findings  Echocardiogram o Hyperechogenic, dense calcification with acoustic shadowing o Caseous MAC is uncommon variant  Echodense mass with echolucent center (liquefaction necrosis)  May mimic neoplasm on echocardiography  M-mode o Measurement of annulus thickness as predictor for stroke and cardiovascular disease  Color Doppler o Concomitant regurgitation or stenosis (rare) MR Findings  Calcium is usually dark on all pulse sequences o In expected location of mitral annulus  Helpful for differential diagnosis of caseous calcification vs. neoplasm DIFFERENTIAL DIAGNOSIS End-Stage Renal Disease  Extraosseous calcification develops due to secondary hyperparathyroidism  Frequently combined with systemic vascular calcification (tunica media) Atherosclerosis  MAC is linked with aortic atheroma and coronary artery disease  MAC may be a pitfall on calcium-scoring CT as MAC can mimic atherosclerotic calcification in left circumflex coronary artery Multivalvular Calcific Disease  MAC is associated with aortic valve calcification, and aortic stenosis may develop 302

Diagnostic Imaging Cardiovascular Caseous Mitral Annular Calcification  Rim-calcified mass containing liquified calcium, which appears toothpaste-like on surgery or pathology (also known as toothpaste tumor) or cheese-like (hence “caseous”) PATHOLOGY General Features  Etiology o End-stage renal disease  Secondary hyperparathyroidism and alterations in calcium metabolism leading to extraosseous calcium deposits o Atherosclerosis  Association with cardiovascular disease, such as stroke, coronary artery disease, and aortic atheroma o Multivalvular calcification: Association with MAC o Tuberculosis o May be a later stage of atherosclerotic disease  Genetics o Genetics may play a role  In patients with end-stage renal disease, ENPP1 genotype is associated with higher severity of systemic arterial calcification  Associated abnormalities o Not usually associated with mitral valve stenosis or regurgitation Gross Pathologic & Surgical Features  Calcification of fibrous base of mitral annulus  Fibroelastic deficiency  If extensive calcification, myocardium may be involved P.4:38

o Prevalence: 12% of surgical specimens  Caseous calcification: Toothpaste-like, white material Microscopic Features  Calcium deposits  Liquefaction necrosis (in case of caseous calcification) CLINICAL ISSUES Presentation  Most common signs/symptoms o Usually asymptomatic o Sometimes mass effect if extensive calcium deposits; if atrioventricular node is affected, atrioventricular block may develop  Other signs/symptoms o Rarely signs of coexistent mitral insufficiency or stenosis o Caseous MAC may cause systemic embolization o Despite presence of MAC, mitral valve repair has favorable results Demographics  Age o Increase with age  > 35% of elderly population  Gender o More common in females  Epidemiology o Prevalence in Framingham Heart Study population: 14% o Prevalence in end-stage renal disease: ˜ 40% Natural History & Prognosis  Slow progression over time  Increased risk of stroke o Dependent of MAC thickness measured by echocardiography o 1 mm increase → 10% increased risk

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MAC is independent predictor of incident ischemic stroke in treated hypertensive patients with left ventricular hypertrophy  3x increased mortality in patients with chronic kidney disease  Predisposing factor for infective endocarditis o Bacterial endocarditis is found in 19% of surgical specimens  Marker for severe coronary artery disease in patients < 65 years of age  Higher prevalence of coronary artery disease and aortic atheroma  Association with incidental atrial fibrillation  Caseous necrosis is rare sequela of MAC o May cause embolic strokes Treatment  Nonspecific if asymptomatic (e.g., calcium metabolism regulation in end-stage renal disease)  Surgery is considered if symptoms are due to mass effect or systemic embolization o 5-year survival after surgery is 76% o Caseous MAC is more frequently surgically resected due to higher prevalence of systolic embolization DIAGNOSTIC CHECKLIST Consider  Mitral valve annulus calcification is benign degenerative disease  Most frequently an incidental finding on chest x-ray or CT o In particular in patients with end-stage renal disease or systemic atherosclerosis  Caseous calcification is rare variant that may mimic tumor o CT and MR imaging can differentiate Image Interpretation Pearls  Posterior annulus base calcification (J-, C-, or U-shaped) and full annulus (O-shaped) at late stage  Best seen on lateral x-ray projections and CT SELECTED REFERENCES 1. Chan V et al: Impact of mitral annular calcification on early and late outcomes following mitral valve repair of myxomatous degeneration. Interact Cardiovasc Thorac Surg. 17(1):120-5, 2013 2. Higgins J et al: Cardiac computed tomography facilitates operative planning in patients with mitral calcification. Ann Thorac Surg. 95(1):e9-11, 2013 3. Okada Y: Surgical management of mitral annular calcification. Gen Thorac Cardiovasc Surg. Epub ahead of print, 2013 4. Eller P et al: Impact of ENPP1 genotype on arterial calcification in patients with end-stage renal failure. Nephrol Dial Transplant. 23(1):321-7, 2008 5. d'Alessandro C et al: Mitral annulus calcification: determinants of repair feasibility, early and late surgical outcome. Eur J Cardiothorac Surg. 32(4):596-603, 2007 6. Lubarsky L et al: Images in cardiovascular medicine. Caseous calcification of the mitral annulus by 64-detector-row computed tomographic coronary angiography: a rare intracardiac mass. Circulation. 116(5):e114-5, 2007 7. Poh KK et al: Prominent posterior mitral annular calcification causing embolic stroke and mimicking left atrial fibroma. Eur Heart J. 28(18):2216, 2007 8. Sharma R et al: Mitral annular calcification predicts mortality and coronary artery disease in end stage renal disease. Atherosclerosis. 191(2):348-54, 2007 9. Cury RC et al: Epidemiology and association of vascular and valvular calcium quantified by multidetector computed tomography in elderly asymptomatic subjects. Am J Cardiol. 94(3):348-51, 2004 10. Atar S et al: Mitral annular calcification: a marker of severe coronary artery disease in patients under 65 years old. Heart. 89(2):161-4, 2003 11. Fox CS et al: Mitral annular calcification predicts cardiovascular morbidity and mortality: the Framingham Heart Study. Circulation. 107(11):1492-6, 2003 12. Adler Y et al: Mitral annulus calcification—a window to diffuse atherosclerosis of the vascular system. Atherosclerosis. 155(1):1-8, 2001 13. Harpaz D et al: Caseous calcification of the mitral annulus: a neglected, unrecognized diagnosis. J Am Soc Echocardiogr. 14(8):825-31, 2001 14. Carpentier AF et al: Extensive calcification of the mitral valve anulus: pathology and surgical management. J Thorac Cardiovasc Surg. 111(4):718-29; discussion 729-30, 1996 15. Maher ER et al: Aortic and mitral valve calcification in patients with end-stage renal disease. Lancet. 2(8564):8757, 1987 P.4:39 304

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(Left) Cardiac CT in 4-chamber, 3-chamber, and mitral valve short-axis views show the typical appearance of MAC. Note reversed C shape on the short-axis view and predominantly inferior and lateral AV groove involvement. (Right) LGE MR in a patient with a remote transmural apical myocardial infarction shows a rounded lesion with low internal signal in the AV groove near the mitral annulus and a slightly enhancing rim , corresponding to MAC seen on CT (not shown).

(Left) Axial DWI MR demonstrates multiple bilateral hyperintense signal foci consistent with multiple small embolic infarcts. (Right) Apical 2-chamber view trans-thoracic echocardiogram in the same patient shows an echolucent mass with a hyperechoic rim at the posterior mitral annulus. Clinically, the etiology was uncertain, and MR and CT were subsequently performed for characterization.

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(Left) Short-axis fat T2W FSE image in the same patient shows a high-signal mass lesion in the left AV groove along the posterior mitral annulus. (Right) Paraseptal long-axis views of NECT and volume-rendered thick-slab enhanced cardiac CT in the same patient demonstrate a rim-calcified mass containing lower density material, indicating caseous MAC, likely with some content embolization leading to the cerebral infarct.

Pulmonary Stenosis Pulmonary Stenosis Brett W. Carter, MD Key Facts Terminology  Pulmonary stenosis (PS)  Lesion resulting in obstruction of right ventricular outflow tract Imaging  Radiography: Enlargement of pulmonary trunk and left pulmonary artery  CT o Poststenotic dilation of pulmonary trunk and left pulmonary artery o Thickened, immobile valve leaflets o Small valvular annulus o Pericardial calcification involving aorta and pulmonary trunk may rarely produce acquired PS  MR: Determination of presence and extent of PS o Doming or windsock appearance of pulmonic valve o Narrowing of valve orifice Top Differential Diagnoses  Pulmonary artery hypertension  Idiopathic dilatation of pulmonary trunk  Proximal interruption of pulmonary artery Pathology  Majority of cases are congenital in etiology  Acquired: Rheumatic heart disease, carcinoid syndrome, and infective endocarditis  Severity of PS is determined by pressure gradient across pulmonic valve or pulmonic valve area Clinical Issues  Treatment o Trivial and mild PS: Observation and endocarditis prophylaxis prior to surgical procedures o Moderate and severe PS: Balloon valvuloplasty or surgical valvotomy

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(Left) Graphic shows morphologic features of pulmonary stenosis (PS) characterized by diffuse thickening of the pulmonic valve leaflets and fusion near the commissures, which results in narrowing of the valve orifice (insert). (Right) Frontal chest radiograph of a patient with congenital PS demonstrates enlargement of the pulmonary trunk and left pulmonary artery . Pulmonary artery enlargement is the most common radiographic appearance of PS.

(Left) Axial CECT of a patient with PS demonstrates enlargement of the pulmonary trunk and left pulmonary artery , consistent with post-stenotic dilatation of these vessels. (Right) Oblique axial black blood FSE STIR MR through the pulmonary trunk demonstrates thickening of leaflets of the pulmonic valve and right ventricular muscular hypertrophy secondary to longstanding pulmonary stenosis. P.4:41

TERMINOLOGY Abbreviations  Pulmonary stenosis (PS) Definitions  Lesion resulting in obstruction of right ventricular outflow tract and poststenotic dilatation of pulmonary trunk and left pulmonary artery IMAGING General Features  Best diagnostic clue o Enlargement of pulmonary trunk and left pulmonary artery  Location o Valvular (90%) 307

Diagnostic Imaging Cardiovascular o Subvalvular o Supravalvular Radiographic Findings  Radiography o Most common abnormality is enlargement of pulmonary trunk  Convexity along left mediastinal border inferior to aortic arch o Enlargement of left pulmonary artery may be present o Right ventricular enlargement CT Findings  CECT o Poststenotic dilatation of pulmonary trunk and left pulmonary artery o Right ventricular enlargement o Focal pericardial calcification involving aorta and pulmonary trunk reported as unusual cause of acquired PS  Cardiac gated CTA o Thickened, immobile valve leaflets o Small valvular annulus o Hypoplasia of supravalvular pulmonary trunk may be present MR Findings  MRA o Enlargement of pulmonary trunk and left pulmonary artery  MR cine o Evaluation of pulmonic valve morphology  Thickening ± fusion of valve leaflets  Narrowing of valve orifice  Doming or windsock appearance of pulmonic valve  Phase-contrast imaging o Determination of presence and extent of PS o Determination of volume flow rates across pulmonic valve Echocardiographic Findings  Echocardiogram o Thickening of valve leaflets o Restricted systolic motion and reduced mobility of valve leaflets o Doming or windsock appearance of pulmonic valve o Poststenotic dilatation of pulmonary artery  Color Doppler o Systolic high-velocity flow jet in pulmonary outflow tract Angiographic Findings  Conventional o Not indicated in mild or moderate PS o Patients with severe PS usually undergo cardiac catheterization for confirmatory pressure assessment  Concomitant balloon valvuloplasty may be performed o Useful in evaluating morphology of pulmonary outflow tract, pulmonary arteries, and right ventricle DIFFERENTIAL DIAGNOSIS Pulmonary Artery Hypertension  Enlarged pulmonary trunk and central pulmonary arteries  CTA: Enlargement of pulmonary trunk > 30 mm  High-resolution CT o Precapillary etiologies: Emphysema, fibrosis, honeycomb lung o Postcapillary etiologies: Centrilobular ground-glass nodules, pulmonary edema, pleural effusions o Chronic pulmonary artery hypertension : Patchy ground-glass opacities  Precapillary etiologies: Chronic pulmonary emboli, congenital left-to-right shunts, idiopathic pulmonary artery hypertension  Postcapillary etiologies: Left heart failure and mitral stenosis Idiopathic Dilation of Pulmonary Trunk  Congenital dilatation of pulmonary trunk ± involvement of left and right pulmonary arteries  Pulmonary and cardiac causes of pulmonary artery enlargement must be excluded 308

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Normal pressures in pulmonary artery and right ventricle Enlarged pulmonary artery may appear as rounded opacity along left mediastinal border o May mimic mediastinal mass Proximal Interruption of Pulmonary Artery  Failed development of proximal pulmonary artery  Small ipsilateral lung and hilum on chest radiography  Absence of pulmonary artery on CT  Visualization of ipsilateral collateral systemic and bronchial arteries  Mosaic attenuation may be seen on high-resolution CT Aberrant Left Pulmonary Artery  a.k.a. pulmonary artery sling  Congenital anomaly in which left pulmonary artery arises from right pulmonary artery  Forms “sling” around trachea as it passes between trachea and esophagus  May be associated with abnormalities of tracheobronchial tree and cardiovascular system  May appear as nodular opacity projecting between trachea anteriorly and esophagus posteriorly on lateral chest radiographs  CT and MR are useful for definitive diagnosis P.4:42

PATHOLOGY General Features  Etiology o Congenital  Most common etiology of PS  Isolated in 80% of cases  Additional forms of congenital heart disease present in 20% of cases o Acquired  Rheumatic heart disease  Associated with mitral and aortic valvular diseases  Carcinoid syndrome  Associated with tricuspid valvular disease  Infective endocarditis  Genetics o Generally considered to be multifactorial in origin o Familial forms have been described o May be associated with genetic disorders  Valvular PS  Noonan syndrome  Supravalvular PS  Congenital rubella syndrome  Williams syndrome  Associated abnormalities o Atrial septal defect o Ventricular septal defect o Patent foramen ovale o Tetralogy of Fallot Staging, Grading, & Classification  Severity classification by pressure gradient across pulmonic valve o Trivial stenosis: Gradient < 25 mm Hg o Mild stenosis: Gradient = 25-50 mm Hg o Moderate stenosis: Gradient = 50-80 mm Hg o Severe stenosis: Gradient > 80 mm Hg  Severity classification by pulmonic valve area 2 o Normal PS: 2.5-4.0 cm 2 o Mild PS: < 1 cm o Severe PS: < 0.5 cm2 Gross Pathologic & Surgical Features 309

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Thickening of valve leaflets o Calcification may be present  Partial fusion of commissures  Valve is typically dome-shaped or conical in configuration  Narrowing of central orifice Microscopic Features  Thickening of valve leaflets  Dysplastic valves may be composed of myxomatous tissue o Present in 10-15% of patients with valvular PS CLINICAL ISSUES Presentation  Most common signs/symptoms o Presentation depends on severity of symptoms  Mild PS  Typically asymptomatic  Moderate or severe PS  Signs and symptoms of systemic venous congestion  Mimics congestive heart failure  Other signs/symptoms o Cyanosis in setting of concomitant patent foramen ovale or atrial septal defect Demographics  Age o Age of presentation depends on severity of obstruction  Gender o M:F = 1:1  Epidemiology o Represents 10% of all congenital cardiac defects o 8-12% of all congenital cardiac defects in children  Isolated PS with intact ventricular septum is 2nd most common defect Natural History & Prognosis  Severity of stenosis determines morbidity and mortality o Mild to moderate PS  Usually well tolerated o Severe PS  Decreased cardiac output, right ventricular hypertrophy, congestive heart failure, and cyanosis may develop Treatment  Trivial and mild PS o Observation  Moderate and severe PS o Balloon valvuloplasty or surgical valvotomy  Mild pulmonic regurgitation and right ventricular dilatation may develop following valvuloplasty DIAGNOSTIC CHECKLIST Consider  Pulmonic stenosis in patients with pulmonary trunk and left pulmonary artery enlargement SELECTED REFERENCES 1. Harrild DM et al: Long-term pulmonary regurgitation following balloon valvuloplasty for pulmonary stenosis risk factors and relationship to exercise capacity and ventricular volume and function. J Am Coll Cardiol. 55(10):1041-7, 2010 2. Ryan R et al: Cardiac valve disease: spectrum of findings on cardiac 64-MDCT. AJR Am J Roentgenol. 190(5):W294303, 2008 3. Castañer E et al: Congenital and acquired pulmonary artery anomalies in the adult: radiologic overview. Radiographics. 26(2):349-71, 2006 4. Hwang YJ et al: Severe pulmonary artery stenosis by a calcified pericardial ring. Eur J Cardiothorac Surg. 29(4):61921, 2006 5. Gielen H et al: Natural history of congenital pulmonary valvar stenosis: an echo and Doppler cardiographic study. Cardiol Young. 9(2):129-35, 1999 310

Diagnostic Imaging Cardiovascular 6. Gikonyo BM et al: Anatomic features of congenital pulmonary valvar stenosis. Pediatr Cardiol. 8(2):109-16, 1987 P.4:43

Image Gallery

(Left) Axial CECT of a patient with PS demonstrates enlargement of the pulmonary trunk and asymmetric enlargement of the left pulmonary artery . (Right) Axial CECT of a different patient with chronic PS shows thickening of the right ventricular myocardium . Characteristic pulmonary artery enlargement and thickening of the pulmonic valve leaflets were also seen in this patient (not shown).

(Left) Frontal chest radiograph of a patient with congenital PS demonstrates poststenotic dilatation of the pulmonary trunk and left pulmonary artery , which are characteristically enlarged in PS. (Right) Axial CECT of a pediatric patient with congenital PS shows enlargement of the pulmonary trunk and the left pulmonary artery . Although PS is most commonly congenital in etiology, acquired etiologies include rheumatic heart disease, carcinoid, and endocarditis.

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(Left) Axial NECT of a patient who presented with moderate PS prior to balloon valvuloplasty. Symptoms of moderate and severe PS may mimic congestive heart failure. Note the enlargement of the pulmonary trunk and left pulmonary artery . (Right) Axial CECT of a patient with asymptomatic PS shows thickening of the pulmonic valve leaflets . CT and MRI may demonstrate abnormalities of the pulmonic valve leaflets such as thickening, fusion, and immobility during dynamic imaging.

Pulmonary Regurgitation Pulmonary Regurgitation Kathryn M. Olsen, MD John D. Grizzard, MD Key Facts Terminology  Reversed flow from pulmonary artery (PA) through incompetent or absent pulmonic valve into right ventricle (RV) in diastole Imaging  Retrograde diastolic flow jet into RV on echocardiography or MR cine exams  Trace pulmonary regurgitation is seen in up to 75% of normal patients and is of no clinical consequence  Chest radiographs in cases of significant pulmonary regurgitation show dilated pulmonary artery with normal pulmonary blood flow Top Differential Diagnoses  Atrial septal defect  Pulmonary hypertension  Surgical complication o Balloon valvuloplasty for congenital pulmonic valve stenosis o Postop tetralogy patients with prior pulmonic valve resection Clinical Issues  Patients known to have lesions predisposing to pulmonary regurgitation (prior tetralogy or pulmonic stenosis repair) should have surveillance imaging to detect and quantify Diagnostic Checklist  Consider pulmonary regurgitation when chest x-ray shows prominent PA and enlarged RV without shunt vascularity  Although severity of pulmonary regurgitation may be estimated with echocardiography, quantification best performed with MR

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(Left) Graphic shows the right ventricle (RV) with the RV outflow tract (RVOT) and main pulmonary artery (PA). The blue arrow indicates the direction of the PR jet. Insets show normal diastolic pulmonic valve and diastolic failure of coaptation in a trileaflet pulmonic valve leading to PR. (Right) MR cine shows an enlarged RV and PA in systole (left) and diastole (right). Note the regurgitant jet of PR seen in diastole emanating from the abnormal pulmonary valve in this patient post balloon valvuloplasty for congenital PS.

(Left) Color Doppler echocardiogram of the RV and RVOT shows forward systolic flow (blue jet ) extending from the RV into the PA, with reversal in diastole (red jet ). Note the aliasing in the regurgitant diastolic jet due to the high velocity. The RV apex is noted. (Right) Short-axis MR cine of an RVOT shows a jet of PR extending into the RV from a dilated PA in a patient with a patent ductus arteriosus (PDA) and pulmonary hypertension. Note the flow jet from PDA to PA . P.4:45

TERMINOLOGY Abbreviations  Pulmonary regurgitation (PR) Synonyms  Pulmonary insufficiency (PI) Definitions  Reversed flow from pulmonary artery (PA) through incompetent or absent pulmonic valve into right ventricle (RV) in diastole IMAGING General Features 313

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Best diagnostic clue o Diastolic flow jet entering RV from main PA as visualized on echocardiography or cardiac MR  Location o Jet of PR begins at level of pulmonic valve (when present) and extends into RV cavity  Morphology o Prominent PA and RV o Diastolic flow through pulmonic valve into RV Radiographic Findings  Radiography o Dilated PA with normal pulmonary blood flow o RV enlargement secondary to volume overload in moderate to severe cases o Longstanding &/or severe PR may produce RV failure and enlargement of azygos vein and vena cava o May reflect underlying etiology (findings of pulmonary hypertension, endocarditis, prior surgery) CT Findings  CTA o May show dilatation of main PA and RV if significant PR present  May show postop changes of prior surgery  Asymmetric enlargement of left PA may indicate preceding congenital pulmonic stenosis (PS), which refers to an abnormally narrowed pulmonic valve aperture  Cavitary nodules/septic pulmonary emboli suggest underlying right-sided endocarditis MR Findings  MRA o Enlargement of main PA and RV  Asymmetric enlargement of left PA may indicate preceding or coexisting pulmonic stenosis  Retrograde diastolic flow void (jet) into RV on steady-state free precession (SSFP) or gradient-echo (GRE) MR cine exams  Cine images also provide assessment of RV size and function o RV function is key determinant of whether repair is necessary  Velocity-encoded phase-contrast flow study can measure regurgitant volume Echocardiographic Findings  Echocardiogram o Trace PR is seen in up to 75% of normal patients and is of no clinical consequence o Moderate to severe PR leads to progressive RV enlargement o Acoustic windows may limit visualization in significant number of adults  Color Doppler o Diastolic flow jet into RV emanating from valve, best seen on parasternal long-axis view  Trace PR seen in normal valves is very small and thin o Severity estimated by diameter of regurgitant jet at its origin just below valve o Severe regurgitant jets on color Doppler reach 1-2 cm into RV and last through ˜ 75% of diastole Angiographic Findings  Right heart catheterization rarely necessary but can demonstrate regurgitant flow and enlargement of PA and RV Imaging Recommendations  Best imaging tool o Echocardiography with Doppler color flow imaging or cardiac MR (particularly if functional evaluation necessary)  MR most accurate means to serially follow RV function and volumes in order to guide timely intervention DIFFERENTIAL DIAGNOSIS Congenital Heart Diseases  Atrial septal defect o Usually has shunt vascularity that is not present in PR  Primary pulmonary valve abnormalities o Absent, malformed, or fenestrated leaflets Pulmonary Hypertension  Usually shows more rapid tapering (pruning) of branch vessels as they extend peripherally from hilar regions  Often seen as associated condition, but PR usually mild, pulmonic valve normal, and rarely alters management of underlying disorder 314

Diagnostic Imaging Cardiovascular Surgical Complication  Balloon valvuloplasty for congenital pulmonary valve stenosis o Significant PR most common significant complication; seen in 35% of cases  Postop tetralogy patients who have undergone RV outflow tract enlargement surgery &/or valve resection o Older patients with patch annuloplasty repairs often have free PR with no discernible valve tissue Other Diseases  Carcinoid syndrome, infective endocarditis, Marfan syndrome, iatrogenic (i.e., pulmonary artery catheter) rheumatic heart disease PATHOLOGY General Features  Etiology o Acquired causes are most common P.4:46  Pulmonary artery hypertension  Endocarditis  Post balloon valvuloplasty for valvular PS  Complication of repair of tetralogy of Fallot Primary congenital causes are rare

o Genetics o Variable, depending on etiology  Associated abnormalities o Significant PR will result in RV dilatation and enlargement of main PA Staging, Grading, & Classification  Severity can be measured with cardiac MR and estimated with echocardiography o Echocardiography with color Doppler can estimate severity by measuring size of regurgitant jet, its density and width, and deceleration rate o Cine MR short- or long-axis image stacks can be obtained for calculation of end-diastolic and endsystolic volumes of both right and left ventricles o Velocity-encoded phase-contrast MR can directly measure forward flow, regurgitant flow, and regurgitant fraction Gross Pathologic & Surgical Features  Incompetence of pulmonary valve o Due to annular dilatation in severe pulmonary hypertension o Due to valve resection or disruption in treatment of tetralogy or valvuloplasty patients CLINICAL ISSUES Presentation  Most common signs/symptoms o Usually none if PR is mild o Longstanding or severe PR may result in right heart failure and dyspnea on exertion  Clinical profile o PR often seen in postop tetralogy or PS patients  Symptoms of right ventricle volume overload may be inapparent until significant RV failure is present  Decision regarding timing of pulmonic valve replacement increasingly performed using MR data Demographics  Age o Varies with underlying lesion  If severe , congenital PR may be noted shortly after birth; if due to treatment of underlying congenital lesion, such as PS, it will be apparent after treatment (balloon valvuloplasty)  Epidemiology o Usually benign condition when mild  Patients known to have lesions predisposing them to PR (prior tetralogy or PS repair) should have surveillance imaging to detect and quantify Natural History & Prognosis  Most often mild and clinically insignificant, requiring no treatment  More significant degrees of regurgitation usually associated with underlying abnormality 

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Most often seen secondary to pulmonary hypertension and occurring in otherwise normal valve Can represent significant complication of prior repaired congenital heart disease (e.g., post valvuloplasty for PS, post RV outflow tract enlargement as part of repair of tetralogy of Fallot)

Treatment  Primary pulmonic valve regurgitation is often mild and well tolerated with good prognosis o Valve replacement undertaken when progressive deleterious impact on RV function is demonstrated  As patients may not have symptoms until RV failure supervenes, close follow-up of at-risk patients suggested o Valve treatment options consist of annulus repair or prosthetic valve replacement  Some centers are actively evaluating transcatheter valve replacement techniques  Secondary pulmonary valve regurgitation prognosis is related to underlying etiology (i.e., pulmonary arterial hypertension or chronic left-sided inflow obstruction) o Treatment is directed toward primary disorder DIAGNOSTIC CHECKLIST Consider  Pulmonic regurgitation when CXR shows prominent PA and enlarged RV without shunt vascularity Reporting Tips  Although severity of PR may be estimated with echocardiography, quantification is best performed with MR o Recent studies suggest RV end-diastolic volume analysis using MR is very useful for timing of valve replacement SELECTED REFERENCES 1. Luijnenburg SE et al: Exercise capacity and ventricular function in patients treated for isolated pulmonary valve stenosis or tetralogy of Fallot. Int J Cardiol. 158(3):359-63, 2012 2. Quail MA et al: Impact of pulmonary valve replacement in tetralogy of Fallot with pulmonary regurgitation: a comparison of intervention and nonintervention. Ann Thorac Surg. 94(5):1619-26, 2012 3. Geva T: Repaired tetralogy of Fallot: the roles of cardiovascular magnetic resonance in evaluating pathophysiology and for pulmonary valve replacement decision support. J Cardiovasc Magn Reson. 13:9, 2011 4. Kilner PJ: Imaging congenital heart disease in adults. Br J Radiol. 84 Spec No 3:S258-68, 2011 5. Oosterhof T et al: Opportunities in pulmonary valve replacement. Expert Rev Cardiovasc Ther. 7(9):1117-22, 2009 6. Bouzas B et al: Pulmonary regurgitation: not a benign lesion. Eur Heart J. 26(5):433-9, 2005 7. Rao PS: Pulmonary valve disease. In Alpert JS et al: Valvular Heart Disease. 3rd ed. Philadelphia: Lippincott William and Wilkins, 2000 8. Otto CM: Right-sided valve disease. In Otto CM: Valvular Heart Disease. 1st ed. Philadelphia: W. B. Saunders Co., 1999 P.4:47

Image Gallery

(Left) Frontal chest radiograph shows a prominent main PA with normal hilar pulmonary arteries and normal pulmonary blood flow in a patient with severe PR from prior tetralogy of Fallot repair. Note that no shunt vascularity is present. (Right) Lateral chest radiograph shows right ventricular enlargement in the same patient. Note that no 316

Diagnostic Imaging Cardiovascular left ventricular enlargement is seen and that the hilar pulmonary arteries are normal in size.

(Left) RVOT MR cine image through the pulmonic valve and RV outflow tract shows a prominent systolic flow jet in this patient with carcinoid valve disease. Note the positions of the thickened pulmonic valve leaflets. (Right) RVOT MR cine image in diastole through the pulmonic valve shows diastolic flow jet of PR in the same patient. Note the immobility of the abnormally thickened pulmonic valve leaflets , which show little change in position when compared to the systolic images.

(Left) Short-axis MR cine images (systole and diastole ) and in-plane matched flow images (systole and diastole ) show free PR and no discernible valve tissue in this postop tetralogy patient. (Right) Transverse MR cine and velocity-encoded through-plane flow studies (systole and diastole ) show severe PR in this patient. Using the flow-velocity data, forward and regurgitant flow can be calculated and rendered graphically and the regurgitant fraction calculated (33%).

Tricuspid Stenosis Tricuspid Stenosis Christopher M. Walker, MD Suhny Abbara, MD, FSCCT Key Facts Terminology  Tricuspid stenosis (TS) 2  Reduced valve area (< 1 cm = severe TS) Imaging  Echocardiography is best modality to diagnose 317

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o

Thickened and diastolic domed tricuspid leaflets Right atrial (RA) enlargement Dilated inferior vena cava Normal right ventricular function High transvalvular pressure gradient on Doppler (2 mm Hg pressure gradient is considered abnormal) Frequently associated tricuspid regurgitation

o o

Calcified and thickened tricuspid valve leaflets with dilated RA Hepatic venous congestion with dilated vena cavae

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o Diastolic flow void (jet) into right ventricle o RA enlargement Top Differential Diagnoses  Rheumatic heart disease o Most common cause of tricuspid stenosis  Obstruction of tricuspid valve o RA tumor, such as myxoma, or vegetation obstructing valve orifice o Pacemaker lead-induced stenosis  Congenital tricuspid stenosis  Complication of other disease o Carcinoid syndrome, medications (methysergide, ergotamine, fenfluramine ± phentermine), eosinophilic endomyocardial fibrosis, endomyocardial fibroelastosis Diagnostic Checklist  Consider rheumatic fever-induced valve disease when > 1 valve affected

(Left) Composite image shows thickening of the pulmonic and tricuspid valve leaflets with associated valve stenosis due to carcinoid heart syndrome. Fibrous endocardial plaques develop on the tricuspid and pulmonic valves due to tumor metabolites being secreted directly into the hepatic veins in patients with liver metastases. (Right) Axial CECT from the same patient shows numerous contrast-enhancing masses representing carcinoid metastases .

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(Left) Axial CECT shows a large right atrial mass protruding through the tricuspid valve. Axial CT through the liver showed a “nutmeg” appearance, consistent with hepatic venous congestion. (Right) Four-chamber view SSFP MR from the same patient shows a right atrial mass causing a functional stenosis of the tricuspid valve indicated by a spindephasing flow void artifact directed from the tricuspid valve into the right ventricle. P.4:49

TERMINOLOGY Abbreviations  Tricuspid stenosis (TS) Definitions  Reduced valve area (< 1 cm2 = severe TS) IMAGING General Features  Best diagnostic clue o Mean Doppler gradient > 5 mm Hg across valve considered significant TS o Gradient is rarely > 10 mm Hg  Morphology o Thickened and diastolic domed tricuspid leaflets o Right atrial (RA) enlargement o Dilated inferior vena cava Radiographic Findings  Radiography o Chest radiography findings  Marked RA enlargement  Dilatation of superior vena cava and azygos vein  Pulmonary arteries appear normal unless there is associated mitral valve disease CT Findings  NECT o Calcified and thickened tricuspid valve leaflets with dilated RA (area > 20 cm 2)  CECT o Narrow tricuspid valve annulus o Hepatic venous congestion with dilated vena cavae MR Findings  Diastolic flow void (jet) into right ventricle  RA enlargement Echocardiographic Findings  Echocardiogram o 2D echocardiography  Fused leaflets, diastolic doming, RA enlargement  Normal right ventricular function 319

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Transesophageal echocardiography  Transgastric views best for valve anatomy  Color Doppler o Diastolic high-velocity turbulent flow across valve o High transvalvular pressure gradient on Doppler (2 mm Hg pressure gradient is considered abnormal) o Frequently associated tricuspid regurgitation Angiographic Findings  Conventional o Diastolic flow jet and decreased movement of valve leaflets Imaging Recommendations  Best imaging tool o Echocardiography DIFFERENTIAL DIAGNOSIS Rheumatic Heart Disease  Most common cause of tricuspid stenosis  Nearly always associated with mitral stenosis o 3% of rheumatic TS is isolated  50% associated with functional tricuspid stenosis Obstruction of Tricuspid Valve  RA tumor, such as myxoma, or vegetation obstructing valve orifice  Extracardiac neoplasm (“tumor thrombus”)  Pacemaker lead-induced stenosis Congenital Tricuspid Stenosis  Tricuspid atresia Complication of Other Disease  Carcinoid syndrome, medications (methysergide, ergotamine, fenfluramine ± phentermine), eosinophilic endomyocardial fibrosis, endomyocardial fibroelastosis PATHOLOGY General Features  Etiology o Rheumatic heart disease is most common cause o Carcinoid syndrome is 2nd most common cause  Tumor products are secreted directly into hepatic veins, causing deposition of fibrous endocardial plaques on tricuspid and pulmonic valves  Thickening and fusion of tricuspid valve apparatus CLINICAL ISSUES Presentation  Most common signs/symptoms o Fatigue and edema related to low cardiac output  Other signs/symptoms o Fluttering sensation in neck due to giant A waves in jugular venous pulse  Progressive fatigue and anorexia  Hepatomegaly, ascites, and peripheral edema Natural History & Prognosis  Symptoms develop over extended period  Most patients have coexisting mitral valvular disease Treatment  Salt restriction and diuretic therapy  Balloon valvuloplasty  Tricuspid valve replacement DIAGNOSTIC CHECKLIST Consider  Rheumatic fever in setting of multivalvular disease SELECTED REFERENCES 1. Ribeiro H et al: [Pacemaker lead-induced tricuspid stenosis: a report of two cases.] Rev Port Cardiol. 31(4):305-8, 2012

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Tricuspid Regurgitation Tricuspid Regurgitation Christopher M. Walker, MD Suhny Abbara, MD, FSCCT Key Facts Imaging  CT o Dilated inferior vena cava and hepatic veins with systolic reflux of contrast  MR o 4-chamber views and paraseptal long-axis gradient-echo or steady-state free precession views are most helpful for diagnosis o Systolic spin-dephasing flow void (jet) directed from tricuspid valve into right atrium during systole  2D echocardiography o Right ventricular volume overload pattern: Right atrial enlargement, right ventricular enlargement, diastolic ventricular septal flattening, and dilated inferior vena cava and hepatic veins o Size of regurgitant jet orifice at valve and in right atrium is utilized to assess severity and grade of regurgitation o Most widely used modality for diagnosis Top Differential Diagnoses  Primary tricuspid regurgitation o Rheumatic heart disease o Ebstein anomaly o Carcinoid syndrome o Infectious endocarditis o Trauma, atrial tumors, pacemaker leads  Secondary tricuspid regurgitation o Most common cause of tricuspid regurgitation o Right heart failure of any etiology (most commonly resulting from left heart failure) Clinical Issues  Trace to mild tricuspid regurgitation is common and detected by echocardiography in > 70% of patients  Considered physiologic when jet does not extend > 1 cm into atrium

(Left) Frontal radiograph shows right atrial , left atrial , and appendage enlargement in a patient with rheumatic heart disease. (Right) Axial CECT from the same patient shows right atrial enlargement from severe tricuspid regurgitation. The left atrium is dilated and partially calcified from longstanding mitral stenosis. Leaflet calcification is associated wit rheumatic mitral stenosis. 321

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(Left) Four-chamber SSFP MR shows regurgitant flow across the tricuspid valve into the right atrium during systole. The right atrium and right ventricle are dilated, and bilateral pleural effusions are also observable. (Right) Short-axis through plane velocity-encoded cine phase-contrast MR from the same patient shows the regurgitant jet . It is difficult to accurately quantify tricuspid regurgitation by phase-contrast MR due to excursion of the valve plane during the cardiac cycle. P.4:51

TERMINOLOGY Abbreviations  Tricuspid regurgitation (TR) Synonyms  Tricuspid insufficiency, tricuspid incompetence IMAGING Radiographic Findings  Radiography o AP or PA findings  Cardiomegaly with enlarged right atrium and right ventricle  Distension of azygos vein and superior vena cava o Lateral findings  Distended inferior vena cava  Filling of retrosternal clear space CT Findings  NECT o Dilation of right atrium and right ventricle  CECT o Dilated inferior vena cava and hepatic veins with systolic reflux of contrast  Cardiac gated CTA o Tricuspid valve usually not directly visualized on gated CT due to  Presence of extensive mixing artifact from opacified superior vena cava blood and nonopacified inferior vena cava blood  Saline flush may result in fluid density on both sides of leaflets, rendering them invisible o Allows functional assessment of right ventricle, including determination of right ventricular ejection fraction and volumes (which requires retrospective gating and triphasic contrast injection) o Diastolic ventricular septal flattening and shift toward left ventricle due to volume overload o Dilated right atrium, right ventricle, and systemic veins o Delayed gated CT rarely shows incomplete closure (regurgitant orifice) of tricuspid valve in ventricular systole MR Findings  4-chamber views and paraseptal long-axis gradient-echo or steady-state free precession (SSFP) views are most helpful 322

Diagnostic Imaging Cardiovascular  Systolic spin-dephasing flow void (jet) directed from tricuspid valve into right atrium during systole  Dilation of right atrium and right ventricle  Dilation of superior vena cava, inferior vena cava, hepatic, and azygos veins ± systolic flow reversal  Diastolic ventricular septal flattening toward left ventricle Ultrasonographic Findings  Grayscale ultrasound o 2D echocardiography  Right ventricular volume overload pattern: Right atrial enlargement, right ventricular enlargement, diastolic ventricular septal flattening, and dilated inferior vena cava and hepatic veins  These findings are not specific for severe TR and can be due to other entities  Thickened, myxomatous, and retracted leaflets with increased echo reflectance  Color Doppler o Systolic high-velocity flow jet in right atrium o Size of regurgitant jet orifice at valve and in right atrium is utilized to assess severity and grade of regurgitation o Systolic flow reversal in inferior vena cava or hepatic veins Angiographic Findings  Conventional o Right ventriculogram can visualize regurgitant jet  Size of regurgitant contrast cloud in right atrium is used for severity grading o Right heart pressure tracing reveals large V waves in right atrial pressure curve Imaging Recommendations  Best imaging tool o Echocardiography  Protocol advice o Conventional MR gradient-echo (longer echo time) images demonstrate regurgitant jet better than newer SSFP pulse sequences DIFFERENTIAL DIAGNOSIS Primary Tricuspid Regurgitation  Endocardial cushion defects  Rheumatic heart disease o Thickening of valve leaflets &/or chordae tendineae o Almost always occurs with mitral stenosis  Ebstein anomaly o Downward displaced septal leaflet leads to “atrialized” right ventricle o Excessive motion and delayed closure of the valve causes TR  Carcinoid syndrome o Stiffened and immobile leaflets o Tumor metabolites from liver metastases are secreted directly into hepatic veins, causing fibrous endocardial plaque to deposit on right-sided valves o Left-sided valves may be affected in patients with atrial septal defect or patent foramen ovale  Infectious endocarditis o Vegetations on valve leaflets o Predominantly in intravenous drug users  Trauma, atrial tumors, pacemaker leads o Usually presence of secondary findings or history Secondary Tricuspid Regurgitation  Most common cause of TR  Right heart failure of any etiology (most commonly resulting from left heart failure)  Right ventricular hypertension secondary to pulmonic stenosis  Primary pulmonary hypertension and mitral valve disease  Right ventricular systolic pressure gradients > 55 mm Hg produce functional TR  Endomyocardial fibrosis P.4:52

PATHOLOGY 323

Diagnostic Imaging Cardiovascular General Features  Etiology o Any disease that causes abnormalities in tricuspid valve apparatus (annulus, leaflets, chordae, and papillary muscles) can cause TR o Posttransplantation  Moderate to severe TR in 15-20% of heart transplant recipients  May be avoided if modified inferior vena caval anastomosis is performed o Severe TR is occasionally idiopathic  Proposed mechanism: Annular dilatation due to aging, atrial fibrillation, or other causes  Associated abnormalities o Underlying cause of TR  Left ventricular failure  Chronic lung disease  Left ventricular inflow obstruction o Secondary findings of systemic venous hypertension  Hepatic congestion  Deformation and retraction of valve cusps in primary diseases  Myxomatous degeneration  Valve leaflets o Rheumatic heart disease  Thickening  Shortening and retraction of 1 or more leaflets  Associated shortening of chordae tendineae o Infectious endocarditis  Shortening and retraction of 1 or more leaflets  Associated shortening of chordae tendineae o Traumatic destruction of leaflet o Carcinoid syndrome  Fibrous plaques deposit on right-sided leaflets  Occurs in setting of hepatic metastases  Chordae tendineae o Thickening and retraction due to rheumatic fever CLINICAL ISSUES Presentation  Most common signs/symptoms o Wide spectrum; depends on severity and chronicity of regurgitation  In absence of pulmonary hypertension, trace to mild TR is common, well tolerated, and usually asymptomatic  Other signs/symptoms o Pulsations in neck from prominent V waves in jugular venous pulse  Fatigue, exhaustion, and right heart failure  Hepatomegaly, ascites, and peripheral edema Demographics  Epidemiology o Trace to mild TR is common and detected by echocardiography in > 70% of patients o Considered physiologic when jet extends ≤ 1 cm into atrium Treatment  Medical therapy includes preload and afterload reduction in setting of severe TR and right ventricular failure  Surgical therapy is more common with primary TR  Secondary (functional) TR is often treated surgically if another indication for cardiac surgery is also present o e.g., mitral valve surgery, aortic valve surgery, or coronary artery bypass graft  Annuloplasty is most common procedure o 30-40% of patients have residual TR o < 5% require valve replacement in 5 years  Valve replacement surgery when annuloplasty is not feasible or has failed o 5-year survival rate post surgery: ˜ 70% o 10-year survival rate post surgery: ˜ 40% DIAGNOSTIC CHECKLIST 324

Diagnostic Imaging Cardiovascular Consider  Gradient-echo cine white blood sequences in 4-chamber views demonstrate regurgitant jet better than newer SSFP pulse sequences Image Interpretation Pearls  Regurgitation of contrast into enlarged hepatic veins is suggestive of TR on non-gated CECT SELECTED REFERENCES 1. Chen JJ et al: CT angiography of the cardiac valves: normal, diseased, and postoperative appearances. Radiographics. 29(5):1393-412, 2009 2. Marelli D et al: Modified inferior vena caval anastomosis to reduce tricuspid valve regurgitation after heart transplantation. Tex Heart Inst J. 34(1):30-5, 2007 3. Mutlak D et al: Echocardiography-based spectrum of severe tricuspid regurgitation: the frequency of apparently idiopathic tricuspid regurgitation. J Am Soc Echocardiogr. 20(4):405-8, 2007 4. Ohye RG et al: Repair of the tricuspid valve in hypoplastic left heart syndrome. Cardiol Young. 16 Suppl 3:21-6, 2006 5. Yamasaki N et al: Severe tricuspid regurgitation in the aged: atrial remodeling associated with long-standing atrial fibrillation. J Cardiol. 48(6):315-23, 2006 6. Behm CZ et al: Clinical correlates and mortality of hemodynamically significant tricuspid regurgitation. J Heart Valve Dis. 13(5):784-9, 2004 7. Hannoush H et al: Regression of significant tricuspid regurgitation after mitral balloon valvotomy for severe mitral stenosis. Am Heart J. 148(5):865-70, 2004 8. Sadeghi HM et al: Does lowering pulmonary arterial pressure eliminate severe functional tricuspid regurgitation? Insights from pulmonary thromboendarterectomy. J Am Coll Cardiol. 44(1):126-32, 2004 9. Henein MY et al: Evidence for rheumatic valve disease in patients with severe tricuspid regurgitation long after mitral valve surgery: the role of 3D echo reconstruction. J Heart Valve Dis. 12(5):566-72, 2003 10. Braunwald E: Valvular Heart Disease. In Braunwald E: Heart Disease: A Textbook of Cardiovascular Medicine. 6th ed. Philadelphia: W. B. Saunders, 2001 11. Ewy GA: Tricuspid valve disease. In Alpert JS et al: Valvular Heart Disease. 3rd ed. Philadelphia: Lippincott William and Wilkins, 2000 12. Otto CM: Right-sided valve disease. In Otto CM: Valvular Heart Disease. 1st ed. Philadelphia: W. B. Saunders, 1999 P.4:53

Image Gallery

(Left) Axial CECT shows dilation of the right atrium due to severe tricuspid regurgitation. Note tricuspid valve leaflet thickening secondary to carcinoid heart disease. (Right) Frontal radiograph from a 0-day-old neonate shows massive cardiac enlargement from right atrial enlargement associated with Ebstein anomaly. There is decreased pulmonary vasculature, which is a typical finding with this disorder.

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(Left) Four-chamber view SSFP MR shows marked right atrial dilation from tricuspid regurgitation associated with Ebstein anomaly. Note “atrialization” of the right ventricle from apical displacement of the tricuspid valve leaflets relative to the mitral valve . (Right) Four-chamber view SSFP MR shows a dephasing flow jet directed from the tricuspid valve into the right atrium, indicating tricuspid regurgitation. There is an associated valve vegetation from endocarditis.

(Left) Frontal radiograph shows mild left atrial dilation and a markedly enlarged right atrium . The apparent left ventricular dilation is a result of right heart enlargement causing clockwise rotation of the cardiac chambers. (Right) Four-chamber MR from the same patient shows a dephasing jet extending toward the posterior right atrial wall, suggestive of moderate to severe tricuspid regurgitation. There is flattening of the interventricular septum indicating volume overload.

Infective Endocarditis Infective Endocarditis Gudrun Feuchtner, MD Key Facts Terminology  Inflammation of endocardium most commonly affecting valves Imaging  Heart valves are most commonly involved, cardiac chambers less frequently  Metallic devices (prosthetic valves, pacemakers, defibrillators)  TEE is best diagnostic tool

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Cardiac CT can show typical lesions; useful for valvular lesion characterization (soft tissue mass vs. calcification), paravalvular involvement, and prosthetic valve infection Clinical Issues  Predisposing factors: Prosthesis, implantable cardioverter-defibrillator, pacemakers, intravenous drug abuse, immunodeficiency  Septic emboli and hematogenous seeding to remote sites are frequent (often, neurologic symptoms)  Diagnosis is based on clinical and imaging findings according to modified Duke criteria (major and minor) Diagnostic Checklist  Vegetations: Hypodense, irregular, or round-shaped masses of few mm up to > 1 cm size; may be mobile  Perivalvular abscess: Fluid accumulation  Perivalvular pseudoaneurysm: Contrast agent-filled cavity, typically arising from aortic or mitral annulus plane  Leaflet perforation  Fistula: Communication between cardiac chambers &/or aortic root  Prosthetic valves: Paravalvular leak, dysfunction  Valvular regurgitation (&/or stenosis) may occur

(Left) Three-chamber view cardiac CT shows mobile aortic valve vegetation floating in the left ventricular outflow tract. Vegetation is defined as a hypodense mass, typically located on the downside of the valve. (Right) Axial oblique view cardiac CT from the same patient shows the aortic valve vegetation within the left ventricular outflow tract adherent to and immediately below the aortic cusps. Cine images showed the mass to be highly mobile.

(Left) Left coronal oblique cardiac CT in systole in a patient with a bileaflet tilting disc valve shows subvalvular contrast outpouching, consistent with paravalvular pseudoaneurysm with surrounding abscess . Note that the prosthetic valve leaflets are in a normal open position. (Right) Aortic valve short-axis view in systole shows pseudoaneurysms 327

Diagnostic Imaging Cardiovascular with adjacent fluid-density material P.4:55

with 0-30 HU and stranding of periaortic fatty tissue.

TERMINOLOGY Abbreviations  Infective endocarditis (IE) Definitions  Inflammation of endocardium most commonly affecting valves IMAGING General Features  Best diagnostic clue o Valvular vegetations o Paravalvular abscess or pseudoaneurysm  Location o Heart valves are most commonly involved  Cardiac chambers are less frequently involved o Metallic devices (prosthetic valves, pacemakers, defibrillators)  Specific findings o Vegetations: Irregularly shaped masses adherent to endocardium  Can be oscillating (mobile); may cause regurgitation o Paravalvular abscess: Irregularly shaped, inhomogeneous perivalvular mass (e.g., in periannular region, myocardium, pericardium) o Pseudoaneurysm/paravalvular leak: Space filled with contrast agent; communicates with cardiac chambers or aortic root o Leaflet perforation: Discontinuity in cusp o Fistula: Communication between cardiac chambers &/or aortic root o Dehiscence: Rocking motion of prosthetic valve with excursion > 15% in any 1 plane  Nonspecific findings o Pericardial &/or pleural effusion o Septic bronchopneumonia Radiographic Findings  Chest radiography o Septic pulmonary emboli, especially in intravenous drug users o Pleural or pericardial effusion o Bronchopneumonia CT Findings  Cardiac gated CTA o Vegetations (irregularly shaped or round masses; sometimes diffuse irregular thickening of leaflet seen) and leaflet perforation may be seen o Perivalvular abscess and pseudoaneurysm involving  Myocardium, pericardium  Annulus  Coronary sinus, coronary arteries  Aortic root pseudoaneurysm or abscess (“stranding” &/or effusion of periaortic fatty tissue) o Fistula o Regurgitation o Evaluation of coronary arteries before surgery (anatomical relationship to abscess and exclusion of significant coronary stenosis) o Assessment of left ventricular function before surgery MR Findings  Myocardial abscess, aortic root aneurysm, and valve dysfunction can be detected in native valves; prosthetic valves produce artifacts  Bright and black blood images are recommended  Post-gadolinium images will show enhancement of vegetation/abscess Echocardiographic Findings  Echocardiogram o 2D transthoracic echocardiography (TTE) 328

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Vegetation: Echodense irregular mass usually on low-pressure side of valve leaflet with oscillation during cardiac cycle and prolapse into chamber o Transesophageal echocardiography (TEE)  Detailed anatomy of vegetation; mobility  Paravalvular abscess o TEE is most sensitive imaging modality; TTE is less sensitive  Color Doppler o Presence and severity of regurgitation (frequent) and stenosis (rare) Angiographic Findings  Conventional  Left ventricular angiography o Can detect perivalvular abscess Imaging Recommendations  Best imaging tool o Transesophageal echocardiography o ECG-gated cardiac CT before surgery (instead of invasive coronary angiography to avoid risk of embolization) for coronaries and perivalvular involvement  Protocol advice o ECG-gated cardiac CT  Coronary CT angiography scan protocol, but homogeneous enhancement of right and left ventricles advantageous (biphasic contrast agent injection)  Image reconstruction: Multiplanar reformations of valves during diastole and systole; 4D cine imaging DIFFERENTIAL DIAGNOSIS Degenerative or Rheumatic Valve Disease  Thickened cusp (DDx: Rather diffuse and symmetric) and calcification; not oscillating  Cusp prolapse  Ruptured chordae tendinea Prosthetic Valve Dysfunction  Pannus or thrombus  Ruptured synthetic neochordae (DDx: High-pressure side) PATHOLOGY General Features  Etiology o Bacterial infection (common)  Staphylococcus aureus and Streptococcus (80%), or Enterococcus faecalis (10%) P.4:56 

HACEK group (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella) may cause large vegetations > 1 cm  Mycobacterium tuberculosis (extremely rare) o Fungal infection  Candida, Aspergillus (especially in prosthetic valves or compromised immune system)  Amorphous mass of thrombus and inflammatory products Staging, Grading, & Classification  Modified Duke criteria o Major criteria  Positive echocardiography (specific valvular lesions or new onset of regurgitation)  Positive blood culture with typical microorganism o Minor criteria  Fever (> 38°C)  Immunological phenomena (Osler nodes, positive rheumatoid factor, etc.)  Vascular phenomena (major arterial emboli, intercerebral hemorrhage, septic pulmonary embolism, etc.)  Predisposing cardiac condition (e.g., valvular disease, pacemaker, prosthesis, etc.) or intravenous drug abuses  Diagnosis o Definite 329

Diagnostic Imaging Cardiovascular  2 major or 1 major and 3 minor criteria  Pathology or bacteriology of specific valvular lesions o Possible  1 major and 1 minor or 3 minor criteria o Rejected  Alternative firm diagnosis Gross Pathologic & Surgical Features  Vegetation on valve leaflet or prosthetic valve  Myocardial abscess Microscopic Features  Platelet and fibrin thrombus, inflammatory cells, and bacteria CLINICAL ISSUES Presentation  Fever, anorexia, weight loss, and changing heart murmur; signs of heart failure (dyspnea), petechiae  Septic emboli with associated complaints, e.g., neurologic symptoms (most common)  Diagnosis based on clinical and imaging findings according to modified Duke criteria (major and minor) Demographics  Epidemiology o Predisposing factors  Degenerative or rheumatic valve disease  Prosthetic valves, pacemakers, defibrillators  Intravenous drug abuses  Immunodeficiency Natural History & Prognosis  50-75% with prior conditions, including mitral valve prolapse, rheumatic, congenital, degenerative valve disease, or prosthetic valves  IE of prosthetic valve frequently extends to cause abscesses, fistulas, and valve dehiscence resulting in paravalvular regurgitation  Septic emboli and hematogenous seeding to remote sites are frequent (mostly neurologic symptoms)  Severe disease with high mortality up to 40% o Mortality increases if perivalvular involvement Treatment  Long-term intravenous antibiotic therapy based on microbial profile  Indications for surgery o Congestive heart failure due to valvular dysfunction o Antimicrobial therapy failure o Unstable prosthesis o Perivalvular invasion o Fungal or other highly resistant organisms DIAGNOSTIC CHECKLIST Consider  Severe disease with high mortality  TEE is best imaging tool  Cardiac CT is useful before valve surgery to evaluate perivalvular involvement and to exclude coronary artery disease Image Interpretation Pearls  Vegetations and cusp perforation  Perivalvular abscess, pseudoaneurysm SELECTED REFERENCES 1. ACC/AHA et al: ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 114(5):e84-231; 2006. Review. Erratum in: Circulation. 115(15):e409, 2007. Circulation. 121(23):e443, 2010 2. Feuchtner GM et al: Multislice computed tomography in infective endocarditis: comparison with transesophageal echocardiography and intraoperative findings. J Am Coll Cardiol. 53(5):436-44, 2009 3. Panwar SR et al: Identification of tricuspid valve vegetation by computed tomography scan. Echocardiography. 24(3):272-3, 2007 4. Christiaens L et al: Aortic valvular endocarditis visualised by 16-row detector multislice computed tomography. Heart. 92(10):1466, 2006 330

Diagnostic Imaging Cardiovascular 5. Meijboom WB et al: Pre-operative computed tomography coronary angiography to detect significant coronary artery disease in patients referred for cardiac valve surgery. J Am Coll Cardiol. 48(8):1658-65, 2006 6. Sachdev M et al: Imaging techniques for diagnosis of infective endocarditis. Cardiol Clin. 21(2):185-95, 2003 7. Karchmer AW: Infective endocarditis. In Braunwald E: Heart Disease: A Textbook of Cardiovascular Medicine. 6th ed. Philadelphia: W. B. Saunders, 2001 8. Durack DT et al: New criteria for diagnosis of infective endocarditis: utilization of specific echocardiographic findings. Duke Endocarditis Service. Am J Med. 96(3):200-9, 1994 9. Bush LM et al: Clinical syndrome and diagnosis. In Kaye D: Infective Endocarditis. 2nd ed. New York: Raven Press, 1992 10. Sokil AB: Cardiac imaging in infective endocarditis. In Kaye D: Infective Endocarditis. 2nd ed. New York: Raven Press, 1992 P.4:57

Image Gallery

(Left) Three-chamber view cardiac CT shows aortic valve vegetation prolapsing in retrograde fashion into the left ventricular outflow tract. Note a rounded mitral valve mass consistent with a vegetation on the posterior cusp. (Right) Cardiac CTA cross-sectional view of aortic valve shows vegetation on a noncoronary cusp that is causing incomplete coaptation of the aortic valve cusps and, consequently, aortic valve regurgitation.

(Left) Cardiac CT volume-rendered 3D image shows an irregular outpouching of the membranous part of the interventricular septum into the right ventricle, which is filled with contrast-opacified blood. No direct contrast shunting into the right ventricle is identified. (Right) Left ventricular outflow tract (3-chamber view) cardiac CT shows an interventricular membranous septal aneurysm with a hypodense vegetation inside and with septal wall thickening . 331

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(Left) Axial cardiac CT image shows a rounded hypodense mass arising from the posterior mitral valve leaflet, consistent with a vegetation in a patient with mitral valve endocarditis. (Right) Corresponding short-axis view of the mitral valve in the same patient demonstrates diffuse thickening of the anterior leaflet of the mitral valve and small round-shaped posterior mitral vegetation on the posterior leaflet of the mitral valve.

Valvular Prosthesis Valvular Prosthesis Suhny Abbara, MD, FSCCT Key Facts Imaging  Ball-in-cage valves o Starr-Edwards (1965): Initial models used stellite alloy cage; later changed to bare metal cage and silastic rubber ball  Titling disc valves o Björk-Shiley flat (1969) and convexo-concave (1975) disc valves o Convexo-concave disc led to strut fractures in 2% of cases o Medtronic-Hall (previously Hall-Kaster) tilting disc valve (1977)  Bileaflet valves o St. Jude Medical (1977): 1st all-carbon (pyrolite) valve o 1.3 million valves implanted predominantly in aortic and mitral positions  Tissue valves (bioprosthesis) o Carpentier-Edwards porcine xenograft o Pressure-fixed, glutaraldehyde-preserved, and wire-mounted porcine or pericardial valve o Mitroflow bovine pericardial valve o Single piece of glutaraldehyde-preserved bovine pericardium sewn onto nonradiopaque polymer stent  Catheter-delivered valves o May be delivered via transfemoral or transapical approach o Cardiac and vascular CT used for procedure planning (femoral access feasibility, valve sizing) o Edwards SAPIEN transcatheter heart valve system o Balloon expandable; bovine pericardium leaflets sewn onto balloon-expandable stainless steel frame o Medtronic core valve o Porcine pericardium sewn onto nitinol alloy stent o Self expanding

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(Left) PA (inset = lateral) radiograph demonstrates a bileaflet tilting disc mitral valve replacement , which had a paravalvular leak between the mitral annulus and the prosthetic valve ring repaired by transcatheter placement of 2 Amplatzer occluder devices. Note that the devices have 2 dense radiopaque ends . (Right) Average-weighted (inset = volume-rendered) CT MPR in mitral plane shows the calcified mitral annulus and 2 occluder devices across the paravalvular regurgitant orifice .

(Left) Oblique combined volume-rendered and LV long-axis multiplanar reconstruction cardiac CT shows StarrEdwards valves normally seated in aortic and mitral valve positions. Note that the radiopaque caged ball is visible in the mitral valve in the open position. (Right) Volume-rendered multiplanar reconstructed cardiac CT in systole demonstrates Starr-Edwards valves in the aortic and mitral valve positions. The ball now occludes the prosthetic valve annulus (closed position). P.4:59

TERMINOLOGY Definitions  Replacement of diseased native cardiac valves with mechanical valve or tissue graft IMAGING General Features  Location o Aortic valve or atrioventricular valves (mitral or tricuspid); rarely pulmonary in situ replacements  Tricuspid position: Bioprosthesis preferred because of higher risk of thrombus formation in mechanical valves (highest for tilting disc valves) o 1st ball valve was inserted in descending thoracic aorta to treat aortic insufficiency (Hufnagel valve) 333

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Rarely, apical left ventricular to descending thoracic aortic tube graft conduits are used to treat aortic stenosis if in situ aortic valve replacement is deemed too risky Morphology o Ball-in-cage valves  Hufnagel valve  1st caged ball valve developed in 1952  Implanted into descending aorta  ˜ 200 valves implanted  Harken-Soroff valve  1st in situ ball-in-cage valve  1st implanted in March 1960  < 20 valves implanted (aortic only)  Starr-Edwards valve (1965)  Initial models used stellite alloy cage; later changed to bare metal cage  Silastic rubber ball  > 80,000 implanted aortic and 100,000 mitral valves  Still in production  Other ball-in-cage valves  Braunwald-Cutter: ˜ 5,000 implanted; titanium cage covered with Dacron fabric (1968-1979)  Magovern-Cromie: ˜ 7,300 aortic and ˜ 200 mitral valves replaced (1962-1980)  Smeloff-Cutter: Double cage with equator-seating ball; ˜ 72,000 implanted (19661988)  DeBakey-Surgitool: Pyrolite ball; ˜ 1,200 implanted; aortic position only (19671984) o Nontilting disc valves  Kay-Shiley: Flat disc, widely used mitral valve replacement  ˜ 12,000 implanted (1965-1980)  Beall-Surgitool: Flat disc, initially Teflon, later pyrolite disc  ˜ 4,800 implanted; mitral valves only (1967-1985)  Cooley-Cutter: Biconical silicone rubber disc later replaced with pyrolite disc  ˜ 3,000 aortic and mitral valves implanted (1971-1978) o Titling disc valves  Björk-Shiley flat (1969) and convexo-concave (1975) disc valves  Convexo-concave disc was developed to improve flow across valve, but new design led to strut fractures in 2% of cases  Strut fractures have led to prophylactic valve replacements and class action lawsuit that allowed for financial compensation of patients for valve rereplacement  Consequently, convexo-concave and even complication free flat disc valve production was terminated in 1986  ˜ 300,000 flat (aortic and mitral) and ˜ 86,000 convexo-concave (aortic and mitral) disc valves implanted  Lillehei-Kaster tilting disc valve (1970-1987)  2 side prongs hold valve in place  ˜ 55,000 implanted  Omniscience and Omnicarbon valves are newer models and are still in production  Medtronic-Hall (previously Hall-Kaster) tilting disc valve (1977)  Titanium housing with pyrolite disc  Strut traverses hole in disc  Widespread use; > 300,000 aortic and mitral valves replaced  No mechanical failures reported; still in production o Bileaflet valves  St. Jude Medical (1977)  1st all-carbon (pyrolite) valve  1.3 million valves implanted predominantly in aortic and mitral positions  Carbomedics (1986)  ˜ 500,000 implanted in mitral and aortic positions  Housing can be rotated within sewing ring 334

Diagnostic Imaging Cardiovascular  Pyrolite housing and pyrolite discs Other bileaflet valves  Gott-Daggett: ˜ 500 implanted in mitral and aortic position; flexible carbon-coated leaflets (1963-1966)  Kalke-Lillehei: Only 1 implanted due to patient demise within 48 hours; 1st hingeless bileaflet valve (1968)  On-X: New carbon structure allows design modification that may allow for reduced anticoagulation levels (still investigational)  ATS open pivot valve: Bileaflet pyrolite valve with titanium lock ring o Lifelong anticoagulation is necessary for all mechanical heart valves o In general, mechanical valves have longer durability but also more thrombogenic complications than tissue valves Tissue valves (bioprosthesis) o Hancock porcine xenograft  Glutaraldehyde-preserved porcine valve mounted on Dacron-covered polypropylene strut o Carpentier-Edwards porcine xenograft  Pressure-fixed, glutaraldehyde-preserved, and wire-mounted porcine or pericardial valve o Mitroflow bovine pericardial valve  Single piece of glutaraldehyde-preserved bovine pericardium sewn onto nonradiopaque polymer stent  Radiopaque silicone sewing ring is visible on radiographs and CT o Ionescu-Shiley valve P.4:60 

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 Bovine xenograft o Cryopreserved homograft valve o Pulmonary autograft  3 months of anticoagulation are required for tissue valves until sewing ring becomes endothelialized o No anticoagulation is required thereafter  Catheter-delivered valves o Terminology: Transcatheter aortic valve replacement (TAVR)  Formerly, transcatheter aortic valve implantation o May be delivered via transfemoral or transapical approach o Cardiac and vascular CT used for procedure planning  Aortoiliac system is analyzed for access feasibility (minimal diameter ≥ 7 mm, absence of circumferential calcification, excessive angulation/tortuosity, dissections, “coral reef” aorta)  Measurements for sizing and implantation feasibility of valve: Aortic anulus short- and longaxis diameters in systole, anulus circumference, distance from anulus to coronary ostia o Edwards SAPIEN transcatheter heart valve system  Bovine pericardium leaflets sewn onto balloon-expandable stainless steel frame  Balloon expandable o Medtronic core valve  Porcine pericardium sewn onto nitinol alloy stent (nickel titanium)  Self expanding Imaging Recommendations  Best imaging tool o Fluoroscopy or gated CT for assessment of leaflet function o Cardiac gated CT has recently been recognized as suitable tool to identify prosthetic valve endocarditis (small pseudoaneurysms, paravalvular leaks, vegetations) and other causes of dysfunction DIFFERENTIAL DIAGNOSIS Aortic Calcifications  Can mimic aortic valve replacement on non-gated CT Annuloplasty Ring  Usually open ring on radiography or CT CLINICAL ISSUES Presentation  Indications for mechanical valves 335

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Age: < 40 years  Longer expected life: Better durability of mechanical valves is preferred; lifetime anticoagulation is necessary o Aortic root and valve replacement are needed (composite graft) o Anticoagulation is required for other reasons o Previous dysfunctional tissue valve o Dialysis  Indications for bioprosthetic valves o Age: ≥ 65 years  Shorter life expectancy: Lower risk from thromboembolism; anticoagulation is preferred o Previous thrombotic valve complication o Contraindication to anticoagulation o Possible pregnancy Demographics  Ethnicity o Race is not a significant predictor of operative mortality after isolated aortic or mitral valve replacement, in contrast to coronary artery bypass surgery Natural History & Prognosis  Bleeding or thrombotic complications account for 50% of complications of tissue valves and 75% of complications of mechanical valves  Thrombotic and bleeding complication rate with mechanical aortic prostheses (2-4%) is 2x as high as with tissue prosthesis (1-2%) o No difference in thrombotic and bleeding complications in mitral position (˜ 4%)  Mechanical prostheses usually cause subclinical mild chronic hemolysis  Fetal demise occurs in 25-30% of pregnant women with mechanical heart valves on warfarin or heparin  Valve thrombosis occurs in 0.1% per year in aortic position and in 0.35% per year in mitral position  Prosthetic valve endocarditis (PVE) occurs in 1.4-3.1% at 1 year and in 3.2-5.7% at 5 years (cumulative) o Commonly extends beyond valve annulus, resulting in ring abscess and extravasation into abscess cavities o Fistulous tracts and septal tracts are possible o Valve dehiscence may lead to significant paravalvular regurgitation o Myocardial abscess in ˜ 30% of cases in pathology series  PVE agents o Coagulase-negative staphylococci: Most common agent in 1st year (˜ 30%); often agent in nosocomial PVE o Streptococci: More common after 1st year post implantation (˜ 30%) o Staphylococcus aureus: Any time; ˜ 20% of PVE; 40-50% central nervous system complications o Enterococci: Any time; ˜10% of cases o Polymicrobial: ˜ 5% of cases o Gram-negative bacilli, Haemophilus, Candida, fungi, diphtheroids, and other agents are not uncommon o 5-8% are culture negative DIAGNOSTIC CHECKLIST Consider  Check for paravalvular contrast collections and tissue stranding o May be only signs of paravalvular abscess SELECTED REFERENCES 1. Leipsic J et al: The evolving role of MDCT in transcatheter aortic valve replacement: a radiologists' perspective. AJR Am J Roentgenol. 193(3):W214-9, 2009 2. Gott VL et al: Mechanical heart valves: 50 years of evolution. Ann Thorac Surg. 76(6):S2230-9, 2003 3. DeWall RA et al: Evolution of mechanical heart valves. Ann Thorac Surg. 69(5):1612-21, 2000 P.4:61

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(Left) Lateral radiograph and thick MPR CT in a patient with rheumatic heart disease show Medtronic-Hall valves in aortic and tricuspid positions and St. Jude-type valve in mitral position . Note the single curved strut in the Medtronic-Hall valves traversing through a central disc opening. (Right) Axial NECT thick MPR shows Medtronic-Hall valves in aortic and tricuspid positions and St. Jude-type valve in mitral position . Note also the epicardial screw-in lead .

(Left) Oblique coronary CTA volume rendering in diastole shows normal closed aortic and open mitral MedtronicHall tilting disc valve replacements. Note that a single strut traverses the central disc opening. (Right) Oblique coronary CTA volume rendering in systole shows normal open aortic and closed mitral Björk-Shiley tilting disc valve prostheses. The disc has a radiopaque ring but is otherwise radiolucent. Note that 2 struts keep the disc in place.

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(Left) Axial CECT shows partially visualized bileaflet tilting disc valve and an abnormal collection of blood pool density material and fat stranding posterior to the aortic root . (Right) Axial CECT in same patient at the level of the left ventricular outflow tract (LVOT) shows defect in the LVOT wall with a pseudoaneurysm due to endocarditis tracking posterior and inferior to the noncoronary sinus of Valsalva, which was contiguous with the more superior collection. P.4:62

(Left) Oblique cardiac CT volume-rendered images are from a patient with St. Jude mechanical prosthetic valves in the aortic and mitral valve position. This diastolic reconstruction shows open position of the mitral valve and closed position of the aortic valve. (Right) Three-chamber view cardiac CT combined volume-rendered and MPR reconstruction (same patient) shows a large subvalvular defect with contrast extending into the perivalvular area, consistent with endocarditic pseudoaneurysm .

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(Left) Aortic root short-axis view cardiac CT shows large abnormal circumferential contrast pool representing a large pseudoaneurysm due to endocarditis. (Right) Fluoroscopy image is fused with cardiac CT dataset to provide a road map, to determine the optimal fluoroscopic plane for TAVR deployment, and to determine coronary ostia location. Note a stented valve during deployment centered around annulus markers (red dots); also note coronary ostia markers and TEE probe .

(Left) AP radiograph shows normally seated TAVR with stented Edwards SAPIEN valve in aortic position . Note 2 valves in the proximal descending aorta due to malposition during partial deployment. Due to failure to correct positioning, the valves were retracted and then fully deployed in the descending aorta. (Right) Lateral radiograph (same patient) shows the normally seated stented Edwards SAPIEN valve in the aortic position and the 2 valves in the proximal descending aorta . P.4:63

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(Left) PA and lateral (inset) radiographs show normal appearance of Mitroflow bioprosthetic aortic valve replacement. Note the characteristic appearance of the radiopaque silicone sewing ring . The stent that holds the pericardial leaflets in place is radiolucent and not seen (unlike Carpentier-Edwards valve). (Right) Aortic root long-axis view and volume-rendered cardiac CT (same patient) show the 3 low-attenuation struts that hold up the pericardium. Note the radiopaque sewing ring .

(Left) Aortic valve short-axis view cardiac CT images from the level of valve coaptation (top left) down to the annulus show normal appearance of Mitroflow valve. Note radiolucent stents inside the circumferential pericardium, allowing for leaflet-like function of the pericardium. (Right) Aortic root long-axis MPR/VRT cardiac CT shows normal connection of Carpentier-Edwards bioprosthesis to aortic annulus on 1 side but dehiscence with paravalvular regurgitant orifice on the other side .

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(Left) Three-chamber view cardiac CT shows well-seated Carpentier-Edwards bioprosthetic aortic valve replacement. The metallic struts are visible , and the valve sewing ring extends all the way to the aortic annulus without a gap to suggest paravalvular leak. (Right) Aortic valve short-axis cardiac CT shows normally seated Carpentier-Edwards aortic valve in systole. Note that the leaflets are densely calcified and the systolic opening orifice is reduced, consistent with stenosis.

Prosthetic Valve Complications Prosthetic Valve Complications Suhny Abbara, MD, FSCCT Key Facts Imaging  Metallic valve dysfunction if severe metal artifacts impaired image quality on echocardiography  General imaging findings o Perivalvular abscess and pseudoaneurysm may be seen o Paravalvular leak o Dehiscence (rocking valve motion > 15° in any 1 plane) o Pannus/thrombus (rather mechanic) o Regurgitation (more common) or stenosis (less common) o Infective endocarditis (vegetations, abscess, cusp perforation): May or may not cause dysfunction o Frozen disc: Causes severe regurgitation o Broken or disrupted metallic leaflets o Impaired metallic leaflet motion due to pannus, thrombus, or vegetation  CT to exclude coronary artery disease before surgery  Fluoroscopy is gold standard for suspected frozen leaflet evaluation  Transcatheter aortic valve replacement (TAVR) o Paravalvular leak is common o Associated with increased morbidity and mortality Top Differential Diagnoses  Infective endocarditis; thrombosis, pannus Clinical Issues  Chronic: Gradual onset of congestive heart failure symptoms  Acute: Acute heart failure symptoms o Most common etiology is infective endocarditis  Severe clinical symptoms if prosthetic valve dysfunction is caused by acute infective endocarditis  Sepsis, thromboembolic events (stroke)  Systemic emboli (e.g., pulmonary)

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(Left) Oblique fluoroscopy in systole and diastole shows aortic St. Jude-type bileaflet tilting disc with a frozen leaflet and a normally functioning leaflet . Frozen disc in closed position causes stenosis, and open position results in regurgitation. Note mitral valve replacement . (Right) VRT cardiac CT shows mitral and aortic bileaflet tilting disc prostheses. Note a frozen leaflet and a normally functioning leaflet .

(Left) Oblique cardiac CT shows a bileaflet tilting disc valve in aortic position with contrast extravasating from the left ventricular outflow tract (LVOT) into the perivalvular tissue , consistent with pseudoaneurysm due to endocarditis. No paravalvular connection between LVOT and aortic lumen was seen. (Right) Aortic valve short-axis cardiac CT in a combined multiplanar reformation and VRT view shows the prosthetic valve nearly circumferentially surrounded by a large contrast collection, consistent with a pseudoaneurysm . P.4:65

TERMINOLOGY Synonyms  Prosthetic valve endocarditis Definitions  Dysfunction depends on prosthesis type o Mechanical prostheses  Caged-ball valve (Starr-Edwards): Oldest  Tilting disc (Lillehei-Kaster, Björk-Shiley, Medtronic-Hall)  Bileaflet (St. Jude): Currently most commonly implanted, lowest thrombogenicity o Bioprostheses (“tissue valves”): Either stented or nonstented  Homograft  Xenograft-porcine: Hancock, Carpentier-Edwards, Medtronic-Intact 342

Diagnostic Imaging Cardiovascular  Autograft (Ross procedure: Pulmonary valve into aortic position) IMAGING General Features  Best diagnostic clue o Endocarditis may show thickened leaflets, fenestrations and regurgitation in bioprosthetic valves, valve dehiscence, paravalvular abscess, and pseudoaneurysm  Dependent on type of prosthesis o All types  Paravalvular leak  Perivalvular pseudoaneurysm  Dehiscence (rocking valve motion > 15° in any 1 plane)  Pannus/thrombus (rather mechanic)  Regurgitation (more common) or stenosis (less common)  Infective endocarditis (vegetations, abscess, cusp perforation) may or may not cause dysfunction  Frozen disc: Causes severe regurgitation o Mechanic valves, specific findings  Broken or disrupted metallic leaflets  Impaired metallic leaflet motion due to pannus, thrombus, or vegetation  Ball (Starr-Edwards) or disc dislodgement o Bioprosthetic valve, specific findings  Chronic degenerative tissue destruction, cusp perforation, and calcification o Transcatheter aortic valve replacement, specific findings  Paravalvular leak is common  Associated with increased morbidity and mortality  Proximal migration  Occlusion of coronary ostium if stent is placed too high, leading to fatal myocardial infarction  Other complications include stroke and need for new permanent pacemaker and dialysis o Mitral valve annuloplasty, specific findings  Systolic anterior movement of anterior mitral valve leaflet causing obstruction of left ventricular outflow tract  Disruption of synthetic neochordae Radiographic Findings  Chest radiography o Mechanical valve: Ball or disc dislodgement o Bioprosthetic valve: Calcification indicates chronic inflammatory process CT Findings  Cardiac gated CTA o Useful for preoperative evaluation of perivalvular pseudoaneurysm o Useful for mechanical prosthesis if echocardiography is limited by massive metal artifacts o 4D dynamic cine imaging for  Dehiscence  Mobility of disc or semi discs  Coexistent valvular regurgitation or stenosis  Mobility of vegetations, thrombus, pannus  Disruption of prosthetic valve leaflets o Coronary CT angiography  Exclusion of coronary artery disease (stenosis > 50%) before surgery MR Findings  Same as general features above  May quantify stenosis or regurgitation for specific valve  Metallic components may cause artifacts resulting in signal void Echocardiographic Findings  Echocardiogram o Transesophageal better than transthoracic to clarify etiology, particularly of mitral valve prosthesis  Color Doppler o De novo regurgitation (more common) or stenosis (rare)

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Mechanical prostheses: Mild regurgitation is normal, each type has a specific retrograde flow pattern (except Starr-Edwards: No regurgitation)  Bioprostheses: No regurgitation but may develop if chronic-degenerative dysfunction o Paravalvular leakage  Eccentric Doppler jet, typically with “half moon” or “sickle” shape o Thrombus or pannus  Eccentric inflow pattern because leaflet motion is impaired  Thrombus: Lower echogenicity  Pannus: Higher echogenicity Angiographic Findings  Conventional  Mechanical valve: Rocking of a dehiscing prosthesis, strut separation  Paravalvular leakage, regurgitation, and stenosis  Exclusion of coronary artery disease before redo surgery o Invasive catheter manipulation is associated with high risk of embolization if mobile vegetations/thrombus Nuclear Medicine Findings  18F-FDG PET/CT has been used for diagnosing prosthetic valve endocarditis o Abnormal increase in FDG uptake has positive predictive value of 85% and negative predictive value of 67% P.4:66

Imaging Recommendations  Best imaging tool o Echocardiography (transesophageal preferred over transthoracic) o ECG-gated cardiac CT useful for  Metallic valve dysfunction if severe metal artifacts impair image quality on echocardiography  Perivalvular abscess and pseudoaneurysm before surgery  Coronary artery disease before surgery  Protocol advice o ECG-gated cardiac CT: Separate image evaluation during systole and diastole (for dehiscence and coexistent regurgitation or stenosis) Fluoroscopic Findings  Fluoroscopy is gold standard for suspected frozen leaflet evaluation DIFFERENTIAL DIAGNOSIS Infective Endocarditis  Vegetations may or may not cause dysfunction  Periprosthetic valve abscess, pseudoaneurysm, and tissue destruction involving myocardium, pericardium, and coronary sinus Thrombosis, Pannus  Mechanical prosthesis  Hypodense lesion or mass on CT o Thrombus: Lower CT density o Pannus: Higher CT density  Can cause impaired movement of prosthetic leaflets  ˜ 20% of tricuspid valve replacements PATHOLOGY General Features  Etiology o Mechanical valve failure is rare o Bioprosthetic valve failure is more common Microscopic Features  Bioprostheses dysfunction o Fibrin deposition, calcification, fibrosis CLINICAL ISSUES Presentation 344

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Most common signs/symptoms o Dependent on whether acute or chronic dysfunction  Chronic: Gradual onset of congestive heart failure (CHF) symptoms  Acute: Acute heart failure symptoms  Most common etiology is infective endocarditis  Clinical profile o Severe clinical symptoms if prosthetic valve dysfunction is caused by acute infective endocarditis  Sepsis, thromboembolic events (stroke)  Systemic emboli (e.g., pulmonary) Demographics  Epidemiology o Bioprostheses  Preferred in the elderly (men > 65 years; women > 70 years); Ross procedure in children and adolescents  Limited long-term durability: 30% dysfunction after 10 years due to degeneration beginning in 4th-5th postoperative year  Advantage: No long-term anticoagulation necessary o Metallic prosthesis  Excellent long-term durability  35 years for Starr-Edwards Natural History & Prognosis  Failure of mechanical valve apparatus is rare; consider thrombosis or pannus as well as dehiscence  Failure of bioprosthesis is more common with > 25% in 10 years (chronic degenerative process)  Increased risk of infective endocarditis Treatment  Medical therapy for infection, thrombosis, &/or CHF  Surgery is indicated for severe dysfunction, nonresponders, or risk of complications (e.g., embolization) DIAGNOSTIC CHECKLIST Consider  Transesophageal echocardiography is best imaging modality  ECG-gated cardiac CT is useful for o Mechanic prostheses function by 4D cine imaging if metallic artifacts limit echocardiographic evaluation (commonly in aortic position) o Noninvasive exclusion of coronary artery disease before surgery o Visualization of perivalvular abscess, pseudoaneurysm particularly before surgery Image Interpretation Pearls  Thrombus or pannus  Paravalvular leakage  Perivalvular pseudoaneurysm  Dehiscence  De novo regurgitation SELECTED REFERENCES 1. Saby L et al: Positron emission tomography/computed tomography for diagnosis of prosthetic valve endocarditis: increased valvular 18F-fluorodeoxyglucose uptake as a novel major criterion. J Am Coll Cardiol. 61(23):2374-82, 2013 2. Habets J et al: Multidetector CT angiography in evaluation of prosthetic heart valve dysfunction. Radiographics. 32(7):1893-905, 2012 3. Jilaihawi H et al: Meta-analysis of complications in aortic valve replacement: comparison of Medtronic-Corevalve, Edwards-Sapien and surgical aortic valve replacement in 8,536 patients. Catheter Cardiovasc Interv. 80(1):128-38, 2012 4. Pham N et al: Complications of aortic valve surgery: manifestations at CT and MR imaging. Radiographics. 32(7):1873-92, 2012 5. Feuchtner GM et al: Multislice computed tomography in infective endocarditis: comparison with transesophageal echocardiography and intraoperative findings. J Am Coll Cardiol. 53(5):436-44, 2009 P.4:67

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(Left) Oblique CTA shows an aortic Carpentier-Edwards porcine tissue valve (inset shows volume rendering of valve frame). Three discrete extraluminal contrast cavities with surrounding fat stranding indicate prosthetic valve endocarditis with paravalvular abscess. (Right) Oblique coronary CTA volume rendering in the same patient shows 2 of the abscess cavities filled with contrast .

(Left) Coronal non-gated CECT volume rendering in a patient with a prosthetic valve and endocarditis shows a tilting disc valve not fully extending to the aortic anulus, indicating dehiscence. Note the paraprosthetic regurgitant orifice . (Right) Three-chamber view cardiac CT in a different patient with bioprosthetic aortic valve replacement and endocarditis shows a contrast collection extending from the left ventricular outflow tract posteriorly , representing a pseudoaneurysm.

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(Left) Aortic root long-axis view cardiac CT in diastole shows a mechanical aortic valve bileaflet tilting disc prosthesis with a frozen leaflet posteriorly in the closed position, which appears unremarkable on this diastolic image. (Right) Aortic root long-axis view cardiac CT in systole in the same patient shows the frozen posterior leaflet remaining in the closed position, while the other leaflet moves into the open position .

Carcinoid Syndrome Key Facts Terminology  Carcinoid tumor secretion of vasoactive substances causing clinical syndrome of flushing, diarrhea, and bronchospasm Imaging  Echocardiography o Thickened, retracted, highly reflective tricuspid &/or pulmonary valve leaflets  Spin-echo MR sequences o Enlarged right atrium o Thickening of tricuspid and pulmonary valve leaflets  Octreoscan  F18 FDG, although FDG uptake is limited due to low proliferative activity  [68Ga]-DOTA-D-Phe(1)-Tyr(3)-octreotide  18F-labeled somatostatin-receptor ligand Top Differential Diagnoses  Rheumatic heart disease  Other causes of tricuspid or pulmonary valve disease Clinical Issues  Cardiac involvement in 50% of carcinoid syndrome cases o May be the only presentation  Progressive signs of right heart failure  Symptoms are partially controlled with somatostatin analogues, serotonin antagonists, and α-adrenergic blockers  Systemic chemotherapy reduces tumor burden  Selective hepatic artery chemotherapy or embolization is used for liver disease  If small, may be resectable

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(Left) Axial T2W C + FS MR image of the liver shows numerous carcinoid liver metastases . Such a large tumor burden may overwhelm the hepatic metabolism of carcinoid metabolites. The largest metastasis is centered close to the inferior vena cava (IVC) , resulting in increased deposition of carcinoid metabolites into the IVC and hence to the heart. (Right) Coronal octreotide scan MIP image (same patient) shows multiple areas of abnormal liver uptake , consistent with multiple carcinoid liver metastases.

(Left) Four-chamber view echocardiogram in atrial systole (same patient) shows poor atrial contraction , thickened, fixed tricuspid leaflets , and poor opening, typical of cardiac carcinoid. Note also that the right ventricle trabeculae is thickened, which is another typical feature of cardiac carcinoid. (Right) Echocardiogram in atrial diastole (same patient) shows an enlarged right atrium , minimal tricuspid valve leaflet movement, and thickened, fixed valve leaflets . P.4:69

TERMINOLOGY Synonyms  Hyperserotonemia  Thorson-Bioerck syndrome  Argentaffinoma syndrome  Cassidy-Scholte syndrome Definitions  Carcinoid tumor secretion of vasoactive substances causing clinical syndrome of flushing, diarrhea, and bronchospasm o Develops from neuroendocrine cells of enterochromaffin cell origin in submucosa 348

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o

Most have midgut origin (ileocecal region/appendix) Origin can also be from primary lung due to common origin of foregut and respiratory diverticulum during 4th week of fetal development Clinical symptoms occur when secretory products are directly released into systemic circulation or when hepatic metabolism is overwhelmed  Cells secrete vasoactive substances  Serotonin (5-hydroxytryptamine [5-HT]) production is most prominent, especially in midgut tumors  Bradykinins, tachykinins, histamine, substance P, and adrenocorticotrophic hormone (ACTH) are also reported  Tumor products activate mitogenic pathways on exposed endocardial surfaces inducing valvular fibrosis  Tricuspid and pulmonary valves are involved on upstream side where vasoactive substance levels are highest  2nd most common cause of tricuspid stenosis (there is always concomitant regurgitation)

IMAGING General Features  Best diagnostic clue o Echocardiography shows thickened, retracted, highly reflective tricuspid &/or pulmonary valve leaflets  Location o Tricuspid and pulmonary valves are most commonly involved  Tricuspid regurgitation is the most common abnormality o Left-sided cardiac involvement is seen in only 7% of patients with bronchial carcinoids or right-to-left intracardiac shunts  Thickened leaflets similar to rheumatic involvement  Flow abnormalities related to degree of valve involvement Radiographic Findings  Radiography o Chest radiography findings  Enlarged cardiac silhouette  Right atrial enlargement  Systemic venous hypertension  Large azygos vein on AP film  Superior vena cava on lateral film  Pulmonary nodule/mass in primary pulmonary disease  Decreased pulmonary vascularity in presence of severe pulmonic stenosis CT Findings  CTA o Thickened, retracted tricuspid and pulmonic valves  Functional data set may show fixed, nonmobile leaflets o Enlarged right atrium and ventricle o Pulmonary nodules in primary pulmonary disease o Decreased pulmonary vascularity in presence of severe pulmonary stenosis MR Findings  Spin-echo MR sequences show enlarged right atrium and thickening of tricuspid and pulmonic valve leaflets  Bright blood steady-state free precession cine sequences show functional tricuspid and pulmonary regurgitation and stenosis  Phase-encoding sequences allow quantitative analysis of tricuspid and pulmonary regurgitation and stenosis Echocardiographic Findings  Echocardiogram o Color Doppler is used to semiquantitatively identify jets o Continuous-wave (CW) spectral Doppler is used to measure peak transvalvular velocities and pressure half-time (inversely proportional to valve area)  Tricuspid valve: Regurgitation (97%); stenosis (59%)  Tricuspid leaflets may be shortened, thickened, retracted and show incomplete coaptation  Leaflets and papillary muscles may appear highly reflective

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CW Doppler shows characteristic dagger-shaped profile with early peak pressure and rapid decline due to rapid equalization of right atrial and ventricular pressures Pulmonic valve: Regurgitation (50%); stenosis (25%)  Pulmonic valve leaflets characteristically stay open in fixed position

Angiographic Findings  Ventriculography o Enlarged right atrium and ventricle o Regurgitant jet of contrast into right atrium when contrast is injected into right ventricle o Regurgitant jet of contrast into right ventricle when contrast is injected into pulmonary outflow tract Nuclear Medicine Findings  PET o F18 FDG, although FDG uptake is limited due to low proliferative activity o [68Ga]-DOTA-D-Phe(1)-Tyr(3)-octreotide o 18F-labeled somatostatin-receptor ligand o Octreoscan  Radiolabeled octreotide using either conventional scintigraphy or SPECT imaging Imaging Recommendations  Best imaging tool o Echocardiography P.4:70

o Cardiac MR DIFFERENTIAL DIAGNOSIS Rheumatic Heart Disease  Presence of mitral &/or aortic valve disease is required Other Causes of Tricuspid or Pulmonary Valve Disease  Fenfluramine and phentermine usage  Right atrial tumor obstructing valve orifice  Endocarditis  Extracardiac neoplasm  Ebstein anomaly o Displacement of septal and posterior leaflets towards apex o Large atrialized portion of right ventricle o Sail-like anterior tricuspid leaflet PATHOLOGY General Features  Genetics o Most carcinoid tumors are sporadic o Foregut carcinoids are associated with type 1 multiple endocrine neoplasia in ˜ 10% of cases and also (rarely) with type 2 multiple endocrine neoplasia or type 1 neurofibromatosis  Macroscopically, valves appear thickened and may be partly fused o Extensive diffuse infiltration from valves to myocardium may cause restrictive cardiomyopathy Gross Pathologic & Surgical Features  Coaptation of nodular thickened valve leaflets is impaired  Fibrous plaque coating on leaflets and papillary muscles Microscopic Features  Fibrous plaques are composed of smooth muscle cells mixed with mucopolysaccharide and collagen  Fibrous plaques may be mediated by serotonin 1B receptor subtype, which induces fibroblast proliferation on in vitro stimulation CLINICAL ISSUES Presentation  Most common signs/symptoms o Cutaneous flushing, telangiectasia, diarrhea, and (occasionally) bronchoconstriction  Other signs/symptoms o Cardiac involvement in 50% of carcinoid syndrome cases, but may be the only presentation  Progressive signs of right heart failure  Elevated jugular venous pulse, prominent V wave 350

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Edema Ascites Pansystolic murmur along left sternal border with inspiratory accentuation (tricuspid regurgitation)

Natural History & Prognosis  Cardiac involvement occurs in up to 50% of patients  Mean life expectancy o With carcinoid heart disease: 1.6 years o Without carcinoid heart disease: 4.6 years Treatment  Medical o Therapy for right heart failure o Partial control of symptoms via  Somatostatin analogues  Serotonin antagonists  α-adrenergic blockers o Systemic chemotherapy to reduce tumor burden  Interventional o Selective hepatic artery chemotherapy or embolization for liver disease o Balloon angioplasty for valvular stenosis o Radiofrequency ablation for liver tumor debulking  Surgical o If small, may be resectable o Valve replacement in severe tricuspid regurgitation (high on-table mortality) SELECTED REFERENCES 1. Wang X et al: Comprehensive evaluation of a somatostatin-based radiolabelled antagonist for diagnostic imaging and radionuclide therapy. Eur J Nucl Med Mol Imaging. 39(12):1876-85, 2012 2. Evora PR et al: Carcinoid heart valve disease: still a puzzle and a challenge. Arq Bras Cardiol. 97(5):e111-2, 2011 3. Graham MM et al: Radiopeptide imaging and therapy in the United States. J Nucl Med. 52 Suppl 2:56S-63S, 2011 4. Haugaa KH et al: Evaluation of right ventricular dysfunction by myocardial strain echocardiography in patients with intestinal carcinoid disease. J Am Soc Echocardiogr. 24(6):644-50, 2011 5. Baumgartner H et al: Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. J Am Soc Echocardiogr. 22(1):1-23, 2009. Erratum in: J Am Soc Echocardiogr. 22(5):442, 2009 6. Sandmann H et al: Cardiovascular magnetic resonance imaging in the assessment of carcinoid heart disease. Clin Radiol. 64(8):761-6, 2009 7. Smith SA et al: Role of serotoninergic pathways in drug-induced valvular heart disease and diagnostic features by echocardiography. J Am Soc Echocardiogr. 22(8):883-9, 2009 8. Gustafsson BI et al: Carcinoid heart disease. Int J Cardiol. 129(3):318-24, 2008 9. Scarsbrook AF et al: Anatomic and functional imaging of metastatic carcinoid tumors. Radiographics. 27(2):455-77, 2007 10. Bastarrika G et al: Magnetic resonance imaging diagnosis of carcinoid heart disease. J Comput Assist Tomogr. 29(6):756-9, 2005 11. Halley A et al: Efficiency of 18F-FDG and 99mTc-depreotide SPECT in the diagnosis of malignancy of solitary pulmonary nodules. Eur J Nucl Med Mol Imaging. 32(9):1026-32, 2005 12. Zuetenhorst JM et al: Metastatic carcinoid tumors: a clinical review. Oncologist. 10(2):123-31, 2005 13. Mollet NR et al: MRI and CT revealing carcinoid heart disease. Eur Radiol. 13 Suppl 4:L14-8, 2003 14. Pellikka PA et al: Carcinoid heart disease. Clinical and echocardiographic spectrum in 74 patients. Circulation. 87(4):1188-96, 1993 15. Hanson MW et al: Carcinoid tumors: iodine-131 MIBG scintigraphy. Radiology. 172(3):699-703, 1989 P.4:71

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(Left) Four-chamber echocardiogram with color Doppler (same patient) shows severe tricuspid regurgitation during right ventricular systole. There is corresponding right atrial dilation . (Right) Axial CT image (same patient) shows very thickened, fixed tricuspid valve leaflets and enlarged right atrium and ventricle secondary to severe mixed tricuspid valve disease. Note straightening of the interventricular septum secondary to increased right heart pressure elevation.

(Left) Axial CT image shows a large right atrial wall mass with invasion through the pericardium into the right cardiophrenic space . Despite the compressive mass effect, the right atrium is grossly dilated secondary to tricuspid valve regurgitation. Biopsy revealed a primary cardiac carcinoid tumor. (Right) Corresponding cardiac MR HASTE image shows heterogeneity in right atrial tumor secondary to hemorrhage and necrosis. Note that the right coronary artery has escaped invasion .

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(Left) Axial CECT shows an enhancing mass in the left lobe of liver. Surgical biopsy confirmed carcinoid metastases. Note its large size, characteristic of carcinoid metastases overwhelming the hepatic metabolism of carcinoid metabolites and systemic IVC deposition (Right) Axial CECT (same patient) shows thickened tricuspid leaflets and papillary muscles and enlarged right atrium and ventricle from mixed tricuspid valve disease. Note flattening of interventricular septum .

Multivalvular Disease Multivalvular Disease Christopher M. Walker, MD Suhny Abbara, MD, FSCCT Key Facts Top Differential Diagnoses  Rheumatic heart disease o Most frequent cause of multivalvular disease o Most common combination is mitral stenosis with aortic stenosis or aortic regurgitation o Classic radiographic findings: Double density of left atrial enlargement, pulmonary venous redistribution, and enlarged pulmonary arteries  Primary single valve disease o Aortic valve disease can lead to functional mitral regurgitation from elevated left ventricular enddiastolic pressure o Mitral valve disease can lead to functional tricuspid regurgitation from pulmonary hypertension and right heart failure  Degenerative calcification o Frequently occurs in mitral regurgitation and aortic stenosis  Infective endocarditis o Extension of infection through mitral-aortic intervalvular fibrosa may cause mitral regurgitation and aortic regurgitation  Marfan syndrome o Mitral valve prolapse is the most common primary valve abnormality o Most patients develop annuloaortic ectasia (tulip-bulb appearance of ascending aorta with effacement of sinuses of Valsalva extending to sinotubular junction)  Carcinoid syndrome o Tumor metabolites from liver metastases cause right-sided valve dysfunction Clinical Issues  Lower postoperative survival if pulmonary arterial hypertension, triple-valve procedure, coronary artery disease, prior sternotomy, diabetes mellitus

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(Left) Frontal radiograph shows a double-density sign and left atrial appendage dilation from marked left atrial enlargement due to mitral stenosis. Note a 2nd convex bulge from associated right atrial enlargement due to tricuspid regurgitation in rheumatic heart disease. (Right) Lateral radiograph in the same patient shows posterior displacement of the left lower lobe bronchus from massive left atrial dilation. Diminished retrosternal clear space is due to right heart enlargement.

(Left) Axial CECT from the same patient shows enlargement of the left atrium with left atrial wall calcification from longstanding mitral stenosis due to rheumatic heart disease. The right border of the left atrium is responsible for the double-density sign seen on the frontal radiograph. (Right) Frontal radiograph from the same patient shows a single-chamber pacemaker lead in the right ventricle, mechanical mitral valve replacement , and tricuspid annuloplasty ring . P.4:73

IMAGING Imaging Recommendations  Best imaging tool o Echocardiography DIFFERENTIAL DIAGNOSIS Rheumatic Heart Disease  Most frequent cause of multivalvular disease  Complication of group A streptococcal pharyngitis  Most common combination is mitral stenosis (MS) with aortic stenosis (AS) or aortic regurgitation (AR)

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Classic radiographic findings include double density of left atrial enlargement, pulmonary venous redistribution (i.e., cephalization), and enlarged pulmonary arteries from pulmonary hypertension  Calcification of mitral valve leaflets (not just the annulus) or left atrial wall may be seen in MS Primary Single-Valve Disease  Primary single-valve lesions can often cause secondary dysfunction in upstream valve o Aortic valve disease can lead to functional mitral regurgitation (MR) from elevated left ventricular end-diastolic pressure o Mitral valve disease can lead to functional tricuspid regurgitation (TR) from pulmonary hypertension and right heart failure o Pulmonic stenosis can lead to functional TR from elevated right ventricular end-diastolic pressure Degenerative Calcification  Frequently occurs in MR and AS Infective Endocarditis  Extension of infection through mitral-aortic intervalvular fibrosa may cause MR and AR  More commonly affects patients with preexisting valve abnormalities (e.g., prosthetic valve, mitral valve prolapse, rheumatic heart disease, or degenerative valve disease)  Transesophageal echocardiography is most sensitive modality for diagnosis Hypertrophic Cardiomyopathy  Asymmetric septal hypertrophy and systolic anterior motion of mitral valve cause subaortic stenosis and MR Marfan Syndrome  Mitral valve prolapse is most common primary valve abnormality and is a minor criteria for diagnosis  Most patients (60-80%) develop annuloaortic ectasia (tulip-bulb appearance of ascending aorta with effacement of sinuses of Valsalva extending to sinotubular junction)  Annuloaortic ectasia leads to incomplete leaflet coaptation and AR  Cardiovascular abnormalities (e.g., aortic dissection) are major causes of mortality  Patients with Ehlers-Danlos syndrome can have similar valve abnormalities Carcinoid Syndrome  Tumor metabolites from liver metastases are secreted directly into hepatic veins, causing fibrous endocardial plaque to deposit on right-sided valves (combined tricuspid and pulmonic valve disease)  Left-sided valves may be affected in patients with an atrial septal defect or patent foramen ovale  Pulmonary carcinoid rarely causes carcinoid syndrome unless tumor is very large or there are hepatic metastases CLINICAL ISSUES Presentation  Most common signs/symptoms o Symptoms dependent on affected valves o Prominent symptoms/signs in 1 valve can mask other valvular lesion(s)  Depends on severity of each valve lesion  In situation where valve damage is equal, proximal upstream valve determines symptoms and masks other distal lesion(s) Natural History & Prognosis  Combined aortic and mitral valve disease o MS with AS or AR is most frequent rheumatic valvular disease combination  Left ventricle is small, stiff, and hypertrophied in cases of AS and MS  Severe MS is usually accompanied by mild AR  Combination of MS and severe AR is uncommon o Myxomatous degeneration can cause AR and MR o AS and MR can produce severe pulmonary congestion  Combined tricuspid and left-sided valve disease o Functional TR occurs in most patients with significant MR due to elevated pulmonary arterial pressures and right ventricular dysfunction o TS occurs in ˜ 30% of patients with MS  Women are more likely than men to get TS with MS  Significant triple-valve disease is rare and usually is the result of rheumatic heart disease Treatment  Double-valve replacement or replacement + valvuloplasty in severe cases  Higher operative mortality: 10%  Low 5-year survival rates; 80% with single-valve replacement; 60% with double-valve replacement 355

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Lower postoperative survival if pulmonary arterial hypertension, triple-valve procedure, coronary artery disease, prior sternotomy, diabetes mellitus DIAGNOSTIC CHECKLIST Consider  Rheumatic heart disease in triple-valve disease SELECTED REFERENCES 1. Morris MF et al: CT and MR imaging of the mitral valve: radiologic-pathologic correlation. Radiographics. 30(6):1603-20, 2010 2. Ha HI et al: Imaging of Marfan syndrome: multisystemic manifestations. Radiographics. 27(4):989-1004, 2007 3. Braunwald E: Valvular heart disease. In Braunwald E: Heart Disease: A Textbook of Cardiovascular Medicine. 6th ed. Philadelphia: W. B. Saunders, 2001 4. Alpert JS et al: Valvular Heart Disease. 3rd ed. Philadelphia: Lippincott William and Wilkins, 2000 P.4:74

Image Gallery

(Left) Composite image from a patient with rheumatic-induced aortic and mitral stenoses shows marked calcification and thickening of the aortic and mitral valve leaflets. The left atrium is dilated, measuring > 4 cm (AP dimension). (Right) Frontal radiograph shows a single-chamber pacemaker lead in the right ventricle and a doubledensity sign of left atrial enlargement. The carinal angle measures > 90° and is a late indirect sign of left atrial enlargement.

(Left) Axial CECT from the same patient after treatment shows mechanical mitral and aortic prosthetic valves. The mitral and aortic valves are the most commonly affected valves in rheumatic heart disease. (Right) Threechamber SSFP MR during ventricular systole shows spin-dephasing jets of aortic stenosis and mitral regurgitation 356

Diagnostic Imaging Cardiovascular in this patient with rheumatic heart disease. Patients with mitral stenosis often have concomitant mitral regurgitation.

(Left) Frontal radiograph shows mechanical aortic and mitral ball in cage valves and a tricuspid valve annuloplasty ring . Rheumatic heart disease is the most frequent cause of multivalvular disease. (Right) Short-axis SSFP MR shows thickening of the mitral valve leaflets in a patient with rheumatic mitral stenosis. Rheumatic heart disease most commonly affects the mitral and aortic valves, leading to mitral stenosis and aortic stenosis/regurgitation. P.4:75

(Left) Four-chamber SSFP MR in diastole shows restricted mitral valve opening, leaflet thickening, and a spindephasing flow jet into the left ventricle, indicating mitral stenosis. (Right) Four-chamber SSFP MR from the same patient now in systole shows a spin-dephasing regurgitant flow jet into the right atrium , indicating tricuspid insufficiency. Mitral valve disease often leads to functional tricuspid regurgitation from pulmonary hypertension and right heart failure.

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(Left) Transthoracic echocardiogram parasternal long-axis view in systole shows mitral and aortic valve nodular thickening, consistent with vegetations in a patient with endocarditis. (Right) Transthoracic echocardiogram parasternal view with color Doppler in diastole in the same patient shows severe aortic regurgitation .

(Left) Parasternal long-axis view transthoracic echocardiogram in diastole shows mitral and aortic valve endocarditis. Note large mitral valve vegetation on the atrial side . Vegetation coats the aortic valve . (Right) Transthoracic echocardiogram parasternal view during systole with color Doppler in the same patient shows severe mitral regurgitation . Extension of infection through the mitral-aortic intervalvular fibrosa leads to mitral and aortic insufficiency. P.4:76

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(Left) Three-chamber SSFP MR obtained during systole shows narrowing of the aortic outflow tract from septal hypertrophy and systolic anterior motion (SAM) of the anterior leaflet of the mitral valve . This narrowing causes the turbulent flow jet across the outflow tract. (Right) Three-chamber SSFP MR from the same patient shows septal hypertrophy and SAM. SAM causes a gap in the mitral closure leading to eccentric mitral regurgitation as the mitral valve is pulled open.

(Left) Frontal radiograph shows marked dilatation and convexity of the ascending aorta consistent with ascending aortic aneurysm. This patient has Marfan syndrome and annuloaortic ectasia. (Right) Coronal thick-slab VRT image from a different patient with Marfan syndrome shows an intimal flap in Stanford type A aortic dissection. Annuloaortic ectasia predisposes patients to aortic regurgitation and aortic dissection. Patients with Marfan syndrome may also have mitral valve prolapse.

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(Left) Axial CECT shows thickening of a tricuspid valve leaflet causing tricuspid stenosis due to carcinoid heart syndrome. (Right) Sagittal CECT from the same patient shows thickening of the pulmonic valve leaflets due to carcinoid heart syndrome. Fibrous endocardial plaques develop on the tricuspid and pulmonic valves due to tumor metabolites being secreted directly into the hepatic veins in patients with liver metastases. P.4:77

(Left) Axial CECT from the same patient shows numerous contrast-enhancing liver masses representing metastatic disease from intestinal carcinoid tumor. (Right) CECT composite image after surgery from the same patient with carcinoid heart disease shows prosthetic tricuspid and pulmonic valve replacements.

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(Left) Frontal radiograph shows marked cardiac enlargement, a single-chamber pacemaker lead terminating in the right ventricle, and a mechanical mitral valve . The presence of pediatric sternal wires is a clue to this being a congenital heart defect. (Right) Oblique axial CECT from the same patient shows a bioprosthetic aortic valve. Extensive aortic wall calcification is seen, which can develop after prior infection. Note mild pectus excavatum deformity.

(Left) Axial CECT from the same patient shows a bileaflet tilting disk mechanical mitral valve and mild pectus excavatum deformity. (Right) Left ventricular outflow tract CECT shows the mechanical mitral valve and bioprosthetic aortic valve with calcification in a patient with Shone syndrome (supravalvular mitral ring, parachute mitral valve, subaortic stenosis, and aortic coarctation). This patient underwent the Konno procedure for subaortic stenosis.

Rheumatic Heart Disease Rheumatic Heart Disease Suhny Abbara, MD, FSCCT Naveen M. Kulkarni, MD Key Facts Terminology  A condition characterized by cardiac valve damage secondary to previous rheumatic fever o Rheumatic fever is a complication of group A β-hemolytic streptococcal pharyngitis (strep throat) in children and adolescents o Rheumatic valve disease may first become apparent years or decades after initial infection  May include valvular stenosis, regurgitation, left ventricular and left atrial enlargement, pericarditis, and heart failure 361

Diagnostic Imaging Cardiovascular  Most commonly affects mitral valve followed, by aortic and tricuspid valve Imaging  Dilated left atrial appendage and left atrium o Right-sided double-density sign on frontal radiograph due to appearance of enlarged left atrium  Calcification of anterior and posterior leaflets of mitral valve (not mitral annular calcification)  Thickening and incomplete opening of the mitral valve leaflets  Stress echocardiography is utilized if there is discordance between findings at rest and clinical findings with exercise Top Differential Diagnoses  Other reasons for left atrial inflow obstruction  Secondary mitral regurgitation  Carcinoid; congenital disease  Medications  Mucopolysaccharidoses; autoimmune disease Pathology  Immune-mediated reaction to Streptococcus bacterium  Mitral valve may demonstrate “fish mouth” or “button hole” configuration

(Left) PA radiograph shows right retrocardiac double density , indicating left atrial enlargement, and convex pulmonary trunk segment due to pulmonary arterial hypertension (secondary to chronic pulmonary venous hypertension). (Right) Lateral radiograph demonstrates enlarged left main pulmonary artery as it arches over the posteriorly displaced left main stem bronchus and enlarged left atrium . The constellation of these findings is characteristic for rheumatic mitral valve disease.

(Left) Oblique SSFP MR at the level of the pulmonary trunk 362

in a patient with rheumatic mitral valve stenosis

Diagnostic Imaging Cardiovascular demonstrates markedly enlarged central pulmonary arteries due to longstanding pulmonary hypertension. Note artifact from sternotomy wires and left pleural effusion . (Right) Long-axis SSFP MR in the same patient demonstrates artifact from prosthetic mitral valve replacement , mild left atrial enlargement, and marked pulmonary arterial enlargement . Note the pleural effusion . P.4:79

TERMINOLOGY Definitions  A condition characterized by cardiac valve damage secondary to previous rheumatic fever o Rheumatic fever is a complication of group A β-hemolytic streptococcal pharyngitis (strep throat) in children and adolescents o Rheumatic valve disease may first become apparent years or decades after initial infection  May include valvular stenosis, regurgitation, left ventricular and left atrial enlargement, pericarditis, and heart failure  Most commonly affects mitral valve, followed by aortic and tricuspid valve IMAGING Radiographic Findings  Dilated left atrial appendage and left atrium o Right-sided double-density sign on frontal radiograph due to appearance of enlarged left atrium o Posterior displacement and slight elevation of left mainstem bronchus  Calcification of left atrial wall  Normal to slightly enlarged cardiothoracic ratio  Calcification of mitral valve leaflets  Interstitial pulmonary edema &/or pulmonary venous redistribution CT Findings  NECT o Enlarged left atrium o Calcification of anterior and posterior leaflets of mitral valve (not mitral annular calcification) o May show calcified left atrial wall  Rarely, extensive calcifications may result in “porcelain heart” appearance  Cardiac gated CTA o Thickening and incomplete opening of the mitral valve leaflets  Essential to perform multiphase imaging and reconstruction  Allows for mitral valve planimetry, although not commonly employed clinically o Allows assessment of additional valvular involvement  Aortic valve > tricuspid valve o May demonstrate left atrial appendage thrombus  Arterial-phase CTA  May be false positive if slow mixing of left atrium contrast with left atrial appendage  Delayed-phase CT  Demonstrates “filling in” of left atrial appendage if negative for thrombus  Demonstrates persistent filling defect if positive for thrombus MR Findings  SSFP gradient-echo images show mitral regurgitation &/or stenosis o Dephasing regurgitant jet indicates insufficiency o Antegrade jet indicates stenosis  May demonstrate diastolic “doming” of mitral valve, indicating stenosis  Evaluate entire mitral valve apparatus o May reveal thickening or retraction of chordae tendineae  Use phase-contrast technique to quantify peak velocity of stenotic jet and amount of mitral regurgitation  May demonstrate enlarged left atrium ± left atrial appendage thrombus o Accuracy of MR for detection of left atrial appendage thrombus is limited o Transesophageal echocardiography remains gold standard for left atrial appendage thrombus  Assess ventricular function and quantify ejection fraction  May demonstrate abnormal late gadolinium enhancement of left atrial wall Echocardiographic Findings 363

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Modality of choice for initial evaluation and for assessment of disease progression Doppler echocardiography is used to calculate pressure half-time valve area and transvalvular gradient Color Doppler can show both mitral stenosis and mitral regurgitation Severe stenosis is classified as having o Transmural gradient > 10 mm Hg o Pulmonary artery systolic pressure > 50 mm Hg o Mitral valve area < 1 cm2  3D echocardiography is an emerging modality that allows for accurate planimetry of valve area  Stress echocardiography is utilized if there is discordance between findings at rest and clinical findings with exercise  Left atrial enlargement  Valvular leaflet thickening, diastolic doming, and incomplete opening of valve  May demonstrate other valve involvement DIFFERENTIAL DIAGNOSIS Other Reasons for Left Atrial Inflow Obstruction  Decreased left ventricular compliance o Restrictive cardiomyopathy o Endomyocardial fibrosis o Dilated cardiomyopathy  Chronic aortic stenosis  Myxoma or other masses Secondary Mitral Regurgitation  Myocardial infarction Carcinoid  Presence of patent foramen ovale may result in predominantly left-sided valve involvement Medications  Methysergide Congenital Disease  Cor triatriatum Mucopolysaccharidoses  Hunter-Hurler subtype Autoimmune Disease  Systemic lupus erythematosus  Rheumatic heart disease P.4:80

PATHOLOGY General Features  Etiology o Pathogenesis is believed to be an immune-mediated reaction to Streptococcus bacterium  End result of what is believed to be an autoimmune reaction to group A Streptococcus leading to fibrinoid degeneration, which results in verrucous appearance of lesions on the valve Gross Pathologic & Surgical Features  Mitral valve may demonstrate “fish mouth” or “button hole” configuration  Pericardium and epicardium are thickened and may demonstrate fibrinous exudates o Pericardial adhesions may be present; however, unlike in other settings, in this setting adhesions do not result in pericardial constriction Microscopic Features  Presence of Aschoff nodules that are characterized by monocyte/macrophage-appearing cells and loss of normal adjacent myocardial muscle with fibrous tissue replacement CLINICAL ISSUES Presentation  Other signs/symptoms o Systemic venous hypertension due to chronic severe multiple sclerosis and elevated pulmonary vascular resistance and right heart failure  Hepatomegaly  Edema 364

Diagnostic Imaging Cardiovascular  Ascites Disease may worsen in pregnant patients or may initially present during pregnancy because of increased cardiac output and heart rate o Typical murmur of mitral stenosis is diastolic rumble at the apex o Atrial fibrillation  Clinical profile o Dyspnea, orthopnea, paroxysmal nocturnal dyspnea o Fatigue due to low cardiac output o Chest pain due to right ventricular ischemia/failure in severe pulmonary hypertension o Syncope o Hemoptysis o Ortner syndrome (hoarseness due to left atrium compressing left recurrent laryngeal nerve) Treatment  Can prevent its development by giving antibiotics when strep throat is detected  Control and treat elevated pulmonary venous pressure and heart failure  Asymptomatic patients with o Severe mitral stenosis should undergo close clinical follow-up and a yearly echocardiogram o Moderate mitral stenosis should undergo echocardiogram every 1-2 years o Mild mitral stenosis should undergo echocardiogram every 3-5 years  Symptomatic patients with moderate to severe mitral stenosis &/or pulmonary hypertension undergo intervention o Mitral valve replacement o Percutaneous mitral balloon valvuloplasty may be used in acute settings or prophylactic treatment for women of childbearing age  Mitral valve annuloplasty has been proposed in patients with mitral regurgitation o Does not reduce mortality DIAGNOSTIC CHECKLIST Image Interpretation Pearls  Convex left atrial appendage segment, right double density, and pulmonary venous redistribution are classic findings of rheumatic mitral valve disease o Convex pulmonary artery segment and large central pulmonary arteries may develop due to back pressure in chronic rheumatic mitral valve disease SELECTED REFERENCES 1. Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC); European Association for Cardio-Thoracic Surgery (EACTS) et al: Guidelines on the management of valvular heart disease (version 2012). Eur Heart J. 33(19):2451-96, 2012 2. Zhang XC et al: Assessment of right ventricular function for patients with rheumatic mitral stenosis by 64-slice multi-detector row computed tomography: comparison with magnetic resonance imaging. Chin Med J (Engl). 125(8):1469-74, 2012 3. Hajsadeghi F et al: Porcelain heart. J Cardiovasc Comput Tomogr. 5(3):183-5, 2011 4. Shriki J et al: Delayed gadolinium enhancement in the atrial wall: a novel finding in 3 patients with rheumatic heart disease. Tex Heart Inst J. 38(1):56-60, 2011 5. ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): developed in collaboration with the Society of Cardiovascular Anesthesiologists: endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons: Circulation. 114(5):e84-231; 2006. Review. Erratum in: Circulation. 115(15):e409, 2007. Circulation. 121(23):e443, 2010 6. Carapetis JR: Rheumatic heart disease in developing countries. N Engl J Med. 357(5):439-41, 2007 7. Carapetis JR et al: Acute rheumatic fever. Lancet. 366(9480):155-68, 2005 8. Carapetis JR et al: The global burden of group A streptococcal diseases. Lancet Infect Dis. 5(11):685-94, 2005 9. Djavidani B et al: Planimetry of mitral valve stenosis by magnetic resonance imaging. J Am Coll Cardiol. 45(12):204853, 2005 10. Lin SJ et al: Quantification of stenotic mitral valve area with magnetic resonance imaging and comparison with Doppler ultrasound. J Am Coll Cardiol. 44(1):133-7, 2004 11. Wyttenbach R et al: Integrated MR imaging approach to valvular heart disease. Cardiol Clin. 16(2):277-94, 1998 12. Braunwald E: Valvular heart disease. In Braunwald E: Heart disease. 5th ed. Philadelphia: W. B. Saunders. 1007-76, 1997 o

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Image Gallery

(Left) PA radiograph shows cardiomegaly with retrocardiac double density , carinal splaying, and convex left atrial (LA) appendage segment due to LA enlargement from rheumatic heart disease. Note convex pulmonary artery segment due to secondary pulmonary hypertension. (Right) Lateral radiograph shows retrosternal clear space filling , indicating right heart enlargement secondary to pulmonary hypertension. Posterior displacement of left mainstem bronchus indicates enlarged LA.

(Left) Mitral valve plane cardiac CT shows thickened anterior and posterior mitral leaflets with incomplete diastolic opening, resulting in “fish mouth” appearance in a patient with untreated rheumatic heart disease. (Right) Aortic valve short-axis image from cardiac CT in the same patient shows thickened cusps and incomplete diastolic closure with central malcoaptation, resulting in a moderate-sized regurgitant orifice .

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(Left) PA radiograph shows cardiomegaly with diffuse calcification of the left atrial wall. A mechanical mitral valve prosthesis and sternotomy wires are present. Note the convex pulmonary artery segment and enlarged central pulmonary arteries, indicating pulmonary hypertension secondary to longstanding pulmonary venous hypertension. (Right) Axial cardiac CT shows left atrial enlargement and confirms diffuse wall calcification .

Left Ventricular Apical Aortic Conduit Left Ventricular Apical Aortic Conduit Suhny Abbara, MD, FSCCT Key Facts Imaging  Extraanatomic valved graft connecting left ventricular apex to descending thoracic aorta  Typically used in patients with severe aortic stenosis and porcelain aorta or other condition precluding median sternotomy (e.g., retrosternal coronary grafts)  Complex congenital left ventricular outflow tract anomalies ± hypoplastic ascending aorta and arch  CT o Gated CT best delineates graft course, implantation angle, proximal and distal anastomoses, and potential complications o Signs of infection include stranding, fluid collection with rim enhancement, and gas formation tracking to skin (fistula)  MRA o Demonstrates graft course and may provide flow information o Phase-contrast MR may be used to quantify ventricular outflow fraction through valved conduit  Echocardiography o May not visualize entire conduit, but presence of Doppler gradients across native left ventricular outflow tract indirectly suggests graft obstruction Pathology  Performed in presence of conditions precluding median sternotomy or aortic disease (porcelain aorta) or congenital disease precluding in situ valve replacement Clinical Issues  Avoid the need to redo sternotomy  Transcatheter aortic valve replacement in native valve position has been used to treat late apicoaortic conduit stenosis

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(Left) Oblique cardiac CT shows an apicoaortic conduit in a patient with aortic stenosis, prior CABG , and increased risk for redoing of sternotomy. Note the slightly oblique but unobstructed inflow cannula ostium , prosthetic valve with the conduit, and distal anastomosis to the descending thoracic aorta . (Right) Oblique cardiac CT VRT shows apicoaortic conduit exiting the left ventricular apex , prosthetic valve , and distal anastomosis with the descending aorta .

(Left) Oblique CECT VRT shows a conduit with a Carpentier-Edwards bioprosthetic valve. There is a small outpouching of contrast in the tubular portion of the conduit just distal to the valve, which corresponds to a cannulation site. (Right) Sagittal CECT in the same patient shows inflow cannula within the left ventricle and small amount of contrast extending beyond the conduit lumen , representing the site of cannulation. Note left pleural effusion and relaxation atelectasis. P.4:83

TERMINOLOGY Synonyms  Apical aortic conduit; apicoaortic conduit  Apicoaortic bypass Definitions  Extraanatomic valved graft connecting left ventricular apex to descending thoracic aorta o Typically used in patients with severe aortic stenosis and porcelain aorta or other condition precluding median sternotomy (e.g., retrosternal coronary grafts) o Complex congenital left ventricular outflow tract anomalies ± hypoplastic ascending aorta and arch IMAGING 368

Diagnostic Imaging Cardiovascular General Features  Best diagnostic clue o Graft connected proximally to apex of left ventricle and distally to descending thoracic aorta or (rarely) to great vessels Imaging Recommendations  Best imaging tool o Gated CT: Best delineates graft course, implantation angle, proximal and distal anastomoses, and potential complications o MRA: Demonstrates graft course and may provide flow information o Echocardiography: May not visualize entire conduit, but presence of Doppler gradients across native left ventricular outflow tract indirectly suggests graft obstruction Radiographic Findings  Radiography o Complete metallic ring (conduit valve) or stented bioprosthetic valve can be seen in mid portion of graft  May be visible lateral to apex on frontal radiograph and projected over inferior middle mediastinum on lateral views CT Findings  Ring of suture cuff can be seen as high-attenuation material surrounding inflow canula at apex  Signs of infection include stranding, fluid collection with rim enhancement, and gas formation tracking to skin (fistula)  May demonstrate pseudoaneurysms at anastomotic sites MR Findings  Shows same morphological features as CT  Phase-contrast MR may be used to quantify ventricular outflow fraction through valved conduit DIFFERENTIAL DIAGNOSIS Ventricular Assist Device  Apical left ventricular graft anastomosis with distal insertion into pump, not aorta  2nd tube graft from pump to (usually) ascending aorta In Situ Valve Replacement  May demonstrate complete metallic ring on radiograph; however, location will correspond to that of replaced valve Coarctation Repair With Extraanatomic Bypass  Tube graft from ascending aorta to descending aorta  Not a valved conduit PATHOLOGY General Features  Performed in presence of conditions precluding median sternotomy or aortic disease (porcelain aorta) or congenital disease precluding in situ valve replacement CLINICAL ISSUES Demographics  Age o Utilized in 2 distinctly different populations  2 weeks to 19 years old patients with congenital heart disease  Elderly (˜ 70 years old) high-risk patients with aortic valve disease and extensive aortic calcification ± prior surgery  Gender o M = F (for congenital indications) Natural History & Prognosis  Longest known survival of functioning conduit graft is > 24 years Treatment  Transcatheter aortic valve replacement in native valve position has been used to treat late apicoaortic conduit stenosis DIAGNOSTIC CHECKLIST Consider  Extend range of gated CT from arch/great vessels to below diaphragm (distal anastomosis location varies) Image Interpretation Pearls  Evaluate angle of apical graft with respect to ventricular septum as this may be flow limiting 369

Diagnostic Imaging Cardiovascular SELECTED REFERENCES 1. Jneid H et al: Transcatheter aortic valve replacement as a treatment for late apicoaortic conduit obstruction in a patient with severe aortic stenosis. Circulation. 127(11):e491-4, 2013 2. Filsoufi F et al: Apicoaortic conduit. Semin Thorac Cardiovasc Surg. 24(3):202-5, 2012 3. Brown JW et al: Long-term results of apical aortic conduits in children with complex left ventricular outflow tract obstruction. Ann Thorac Surg. 80(6):2301-8, 2005 4. Fogel MA et al: Evaluation and follow-up of patients with left ventricular apical to aortic conduits with 2D and 3D magnetic resonance imaging and Doppler echocardiography: A new look at an old operation. Am Heart J. 141(4):6306, 2001 P.4:84

Image Gallery

(Left) Axial CECT in a patient with an apicoaortic conduit shows fat stranding and small amounts of air extending from the tube graft through the chest wall and eventually to the skin (not shown), consistent with graft infection and subsequent fistula formation. (Right) Axial CECT in the same patient shows extension of the inflammatory changes and gas-containing tract toward the skin. Note atelectasis in the lung adjacent to the graft.

(Left) Oblique CECT in a patient with an apicoaortic conduit shows an inflow cannula with some gas-density material within the wall, which can be a normal finding and is not to be mistaken for infection with gas-forming material. Note valve prosthesis in the conduit and artifact from a pacemaker at the right ventricular apex. (Right) Oblique CECT in a patient with an apicoaortic conduit shows that the anterior ribs near the cardiac apex have been resected to make space for the inflow canula.

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(Left) Oblique CECT maximum-intensity projection (MIP) image shows normally seated apical cannula , which protrudes mildly into the chest wall. This is a typical appearance, and focal rib resections may be performed to allow for adequate space near the apex. (Right) Oblique CECT MIP image shows the course of the valved conduit and the distal anastomosis with the descending thoracic aorta . Note small left pleural effusion and atelectasis within the lower lobe. P.4:85

(Left) PA radiograph shows stigmata of prior median sternotomy, aortic valve replacement , and coronary bypass grafting as evident by the LIMA clips alongside the left heart border. Note also a Carpentier-Edwards valve in the aortic position and to the left of the apex , consistent with subsequent apicoaortic conduit. (Right) Lateral radiograph prior to permanent pacemaker placement (same patient) shows the in situ aortic valve replacement and the conduit valve .

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(Left) Oblique cardiac CT VRT in diastole shows an apical cannula exiting at the left ventricular apex. Note the location of the prosthetic valve within the conduit . (Right) Oblique cardiac CT VRT in systole shows decreased volume of the left ventricular cavity, which is narrowest just proximal to the outflow cannula. In patients with midventricular hypertrophy, there may be systolic obliteration of the cavity, which may substantially reduce the blood flow though the conduit.

(Left) Three-chamber view cardiac CT in diastole in a patient post CABG shows severely calcified stenotic native aortic valve and aortic root. An apicoaortic conduit was placed due to heightened risk for resternotomy. Note well-seated inflow cannula and anterior portion of the tube graft . (Right) Three-chamber view cardiac CT in systole shows doming of aortic valve cusps , consistent with severe stenosis. There is systolic narrowing of left ventricular cavity without inflow cannula obstruction.

Section 5 - Pericardial Approach to Pericardial Disease Approach to Pericardial Disease Suhny Abbara, MD, FSCCT Naveen M. Kulkarni, MD Introduction Pericardial pathology is commonly encountered in the clinical practice. Several conditions can alter cardiac function. A spectrum of lesions varying from inflammatory to neoplastic etiologies can involve the pericardium. The clinical presentation ranges from nonspecific to unequivocal physical and physiological findings. Noninvasive imaging techniques, such as echocardiography, cardiac computed tomography (CCT), and cardiac MR (CMR), can play an 372

Diagnostic Imaging Cardiovascular important role in resolving the diagnostic dilemma in patients with suspected pericardial disease. It is imperative to be familiar with key imaging techniques used for the diagnosis of pericardial diseases, and the choice of each technique should be tailored to clinical question. This chapter discusses the potential role of different imaging modalities in the diagnosis and management of pericardial disorders. Which Imaging Test to Choose Although echocardiography has been the primary imaging method for evaluation of the pericardium in the past, CCT and CMR enjoy a number of advantages, especially in cases of loculated or hemorrhagic effusion, constrictive pericarditis, or pericardial masses. Both CCT and CMR not only provide excellent delineation of the pericardial anatomy but they can also aid in the characterization of different pericardial lesions. Although certain pericardial abnormalities can be identified on chest radiography, this modality plays a limited role. An overview of the advantages and limitations of different modalities is provided in the table. Pericardial Effusion and Cardiac Tamponade Several conditions can lead to the development of pericardial effusion. Some common causes include heart failure, infection (viral, bacterial, and tuberculosis), neoplasia, injury (from trauma, myocardial infarction, and aortic dissection), and radiation therapy. Detection of pericardial effusion may also occur in asymptomatic patients who are imaged for other reasons. Although the diagnosis of a probable pericardial effusion (mostly large) can be made on chest x-ray by enlarged cardiac silhouette (“water bottle” configuration) and the absence of pulmonary edema, echocardiography is the modality of choice because it is readily available, lacks ionizing radiation, and has a low cost. Simple pericardial effusion appears as an anechoic space within the pericardial cavity. Further investigation with CCT and CMR is indicated when loculated or hemorrhagic effusion or pericardial thickening is suspected or when findings on echocardiography are inconclusive. Because of the wide field of view, CCT and CMR can easily identify loculated effusions, especially those in anterior locations. CT attenuation measurement can facilitate initial characterization of pericardial fluid. On CCT, simple pericardial effusion (transudate) has density similar to water attenuation (< 10 HU). Attenuation greater than water suggests hemopericardium, purulent exudates, malignancy, or effusion associated with hypothyroidism. Chylopericardium, which is rare, may resemble transudate effusion. Acute hemopericardium has higher density (range: 60-80 HU), whereas subacute hematomas may resemble exudative effusion and sometimes can be difficult to distinguish from transudative effusion. On MR, nonhemorrhagic fluid appears as low signal on T1-weighted images and has high signal intensity on T2-weighted and gradient-echo (GRE) cine images. Conversely, hemorrhagic effusion is characterized by high signal intensity on T1-weighted images and low intensity on T2-weighted and GRE cine images. Subacute and chronic hematomas are usually heterogeneous with both high- and low-signal regions on T1weighted images. When pericardial effusion is secondary to a malignancy, an irregularly thickened pericardium or pericardial nodularity may be observed. Small amounts of pericardial fluid can be misinterpreted on CT because their appearance is similar to pericardial thickening. MR can distinguish low signal of normal parietal pericardium from high signal intensity of small effusion on T2-weighted and GRE cine images. Acute accumulation of pericardial fluid may result in an effusion under tension or cardiac tamponade. Tamponade occurs when cardiac chambers are compressed to the point of compromising systemic venous return to the right heart chamber. Transthoracic echocardiography (TTE) is the imaging modality of choice to assess cardiac tamponade. However, the size of effusion does not always reflect the hemodynamic significance of pericardial effusion. Typical echocardiographic findings include late diastolic collapse of the right atrium and early diastolic collapse of the right ventricle. Persistence of right atrial collapse for more than one-third of the cardiac cycle is highly sensitive and specific for tamponade. Left atrial collapse, which can also occur in tamponade, is very specific but not sensitive for tamponade. Other findings include respiratory variation in mitral and tricuspid inflow, ventricular interdependence, plethora of inferior vena cava, and prominence of diastolic reversals in hepatic veins by pulsed Doppler. Both cine CCT and CMR imaging are useful adjuncts to TTE, which can also demonstrate the dynamic features suggestive of tamponade. If the presence of cardiac tamponade is established by echocardiography, testing by CCT or CMR is usually not required. CCT and CMR are useful when TTE is inconclusive due to larger body habitus or in postoperative setting and more detailed quantification of pericardial effusion is necessary, especially when loculated. Pericarditis Pericarditis refers to inflammation of the pericardium in response to a host of conditions and may or may not be associated with pericardial effusion. Pericarditis may occur as an isolated abnormality or manifestation of an underlying abnormality. Pericarditis can present with or without constriction of the heart. Nonconstrictive Pericarditis Nonconstrictive pericarditis can be further classified as acute or chronic. Pericarditis may occur as an isolated abnormality or as a manifestation of an underlying abnormality. The underlying cause may be infection (usually virallike coxsackievirus B, echovirus, or tuberculosis), inflammatory (such as systemic lupus erythematosus, rheumatoid arthritis, and uremia), HIV, or radiation. The diagnosis of pericarditis is usually suspected clinically and supported by

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The chest radiograph is often normal, although it should be considered to exclude other pulmonary or mediastinal pathologies. TTE is often the initial imaging modality of choice. TTE is recommended to exclude cardiac tamponade, guide diagnostic or therapeutic pericardiocentesis, and when there are features of constrictive physiology. In the proper clinical setting, smooth pericardial thickening (≥ 4 mm) with enhancement on CCT and CMR is suggestive of acute pericarditis. With increasing duration of pericardial inflammation, the smooth pericardium may eventually become irregular. When associated with pericardial effusion, CT attenuation and MR signal characteristics will vary depending on transudative or exudative effusion. One of the important drawbacks of CT is the inability to differentiate small pericardial effusions from pericardial thickening. On CMR, the signal intensity of the pericardium may vary depending on the extent of inflammatory or granulation tissue in acute pericarditis and fibrous tissue or calcification in chronic pericarditis. As on CT, post-contrast enhancement can be seen on CMR. The use of delayed enhancement and CMR is proposed to be a more sensitive method for identifying active pericardial inflammation over inflammation from a fibrosing form of pericarditis. In general, CCT and CMR are used in cases of therapeutic difficulties and complications from acute pericarditis, such as failure to respond to treatment in the recurrent setting to monitor disease activity and treatment response or in chronic pericarditis with constrictive features. Cross-sectional imaging may also be considered when linked to specific conditions, such as neoplastic disorders, and involvement from an adjacent anatomical structure, like empyema. Constrictive Pericarditis Constrictive pericarditis represents the end stage of an inflammatory process. In developed countries, the most frequent causes are cardiac surgery and radiation therapy as opposed to infection, mostly tuberculosis in developing countries. Constrictive pericarditis can clinically mimic restrictive cardiomyopathy, hepatic disease, and congestive heart failure. Clinically, it is difficult to differentiate between constrictive pericarditis and restrictive cardiomyopathy, but correct distinction between them is very important since only constrictive pericarditis can benefit from surgical pericardial stripping, and restrictive cardiomyopathy would not improve. On chest radiograph, pericardial calcifications are strongly suggestive of constrictive pericarditis. However, calcifications are seen only in 20-40% of constrictive cases. Echocardiography is usually the initial diagnostic imaging modality. An important reason to use echocardiography early in the diagnostic process is to rule out other more common causes of right-sided heart failure. Precise assessment of pericardial thickening may be difficult (transesophageal echocardiography, CCT, and CMR are more sensitive than TTE), but diastolic septal motion (septal bounce), a respiratory shift in the position of the interventricular septum, inferior vena cava plethora, and the presence of myocardial tethering are classic 2D features associated with pericardial constriction (none of them particularly sensitive or specific, however). Respirationcorrelated Doppler techniques are particularly useful in the diagnosis of constrictive pericarditis. In restrictive cardiomyopathy, the mitral inflow velocity rarely shows respiratory variation, and hepatic vein systolic flow reversals are more prominent with inspiration. It is worth noting that up to 20% of patients with constrictive pericarditis lack the typical respiratory changes in the presence of mixed constrictive-restrictive disease &/or markedly elevated left atria pressure. Comprehensive echocardiography may provide conclusive evidence of constrictive pericarditis when the picture is complete. However, echocardiographic findings can be equivocal. In these situations, additional testing is greatly supported by the excellent anatomical depiction of the pericardium at CT and MR imaging. CCT findings are centered on the demonstration of thickened (≥ 4 mm) or calcified pericardium with other signs of constriction, including distorted ventricles (conical, tubular, or bullet-shaped), sigmoid-shaped interventricular septum, large atria, coronary sinus, and inferior vena cava. On CMR, changes similar to those on CT are appreciated. Unlike CT, calcification may not be very well visualized on CMR. Spin-echo sequences are useful to detect thickened pericardium, whereas limited pericardial thickening and pericardial effusions are better seen on cine gradient-echo sequence sensitive to pericardial fluid. Myocardial tagging on CMR, which uses a grid-like pattern, can assist in evaluating adherence and immobility of the pericardialmyocardial interface. It is worth remembering that pericardial thickening may be limited to the right side of the heart or even to a smaller area, such as the atrioventricular groove. Neither pericardial thickening nor calcification are diagnostic of constrictive pericarditis, unless the patient also has symptoms of physiologic constriction. Effusive Constrictive Pericarditis Effusive constrictive pericarditis is a relatively uncommon pericardial syndrome characterized by elements of pericardial effusion/tamponade and features of constrictive pericarditis. In patients with effusive constrictive 374

Diagnostic Imaging Cardiovascular pericarditis, hemodynamics related to pericardial construction typically persist even after the pericardial fluid has been removed. Noninvasive imaging demonstrates key imaging findings of pericardial effusion, thickened pericardium, and hemodynamic evidence of constrictive physiology, which can be readily demonstrated by TTE, CCT, or CMR. Pericardial Masses Pericardial masses are often detected initially on chest radiograph or TTE. CCT and CMR are useful for further characterization of these masses. CT attenuation or MR signal intensity, contrast enhancement characteristics, and presence or absence of blood flow on cine MR images can help differentiate pericardial masses. CT and MR imaging also provides a road map for cases that are considered suitable for surgical resection. Extension into or from the mediastinum and lungs can be readily assessed with CCT and CMR. Pericardial Cysts Pericardial cysts are considered congenital in origin and often detected incidentally. On chest radiograph, they often present as radiopacity similar to water/soft tissue in the right cardiophrenic angle. On TTE, they appear as echolucent lesion. However, smaller cysts and those outside the vicinity of a cardiac chamber may not be detected. It is important that they are not misinterpreted as P.5:4 pleural effusion. Contrast echocardiography may be used to exclude an anomalous systemic vein that may present in that location. On cross-sectional imaging, pericardial cysts demonstrate smooth, thin walls and appear inseparable from the heart border. When connection with the pericardial cavity is maintained, it is known as a pericardial diverticulum and is often indistinguishable from a cyst. On CT, the attenuation is similar to that of water, and pericardial cysts do not enhance after contrast material administration. On MR imaging, they are nonenhancing and typically have low or intermediate signal intensity on T1-weighted images and homogeneous high intensity on T2-weighted images. Occasionally, highly proteinaceous content can be seen giving high signal intensity on T1-weighted images. Pericardial cysts may be at an unusual location and occasionally can be indistinguishable from thymic or bronchogenic cysts. Pericardial Tumors Primary pericardial tumors are rare, and most neoplastic pericardial diseases are related to metastases from extracardiac malignancies. Sometimes the pericardium may be involved by a primary cardiac neoplasm of benign or malignant etiology. Benign pericardial tumors include lipoma, fibroma, teratoma, and hemangioma. Malignant tumors include sarcomas, such as liposarcoma and mesothelioma. Lung, breast, and esophageal cancers, melanoma, lymphoma, and leukemia are common extracardiac malignancies that may involve the pericardium. Chest radiograph plays no significant role. The use of TTE may be limited to detection and follow-up of pericardial effusion. Pericardial thickening/nodularity related to metastasis may be appreciated. CCT and CMR, in addition to characterization of pericardial tumor and effusion, also demonstrate local tumor extension. Lipoma typically has low attenuation consistent with fat on CT images and high signal intensity on T1-weighted SE images. Presence of fat &/or calcium in a pericardial mass on CT or MR suggests teratoma. Fibroma, although difficult to characterize on CT, demonstrates characteristically low signal intensity on T2-weighted images and is nonenhancing or shows heterogeneous enhancement because of poor vascularization. Lymphoma, sarcoma, and liposarcoma typically present as large heterogeneous enhancing masses, often with foci of necrosis and frequently associated with pericardial effusion/hemopericardium. Primary malignant mesothelioma of the pericardium may manifest as pericardial effusion accompanied by pericardial nodules or plaques. Pleural mesothelioma may also extend to the pericardium. Congenital Absence of Pericardium Most defects involving the pericardium are congenital but can be iatrogenic in nature or occur secondary to trauma. The partial form of congenitally absent pericardium is more common and occurs along the left side of the heart. It can also occur on the right side or at the diaphragmatic surface, although infrequently. On chest radiographs, leftward displacement of the heart and aortic knob, flattened left cardiac silhouette, long prominent pulmonary artery, radiolucency between the aortic knob and the main pulmonary artery, and a radiolucent band between the left hemidiaphragm and the base of the heart have been described. Exaggerated cardiac motion (especially along the posterior wall of the left ventricle), false appearance of enlarged right ventricular cavity due to shifting of axis, compressed atria, and altered apical imaging window toward the axilla can be appreciated on TTE. The findings on CT and MR imaging rely on the lack of visualization of the pericardium and on other signs, including displacement of the cardiac axis to the left side and posteriorly, prominent atrial appendage, and separation of the aorta and main pulmonary artery due to lung tissue interposition. Patients with pericardial defects may also have one or more associated congenital abnormalities, such as patent ductus arteriosus, mitral valve stenosis, atrial septal defect, or tetralogy of Fallot, which are also detectable on CCT or CMR. The partial absence of the pericardium is usually associated with increased but rare risk of herniation and

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Diagnostic Imaging Cardiovascular strangulation of the left atrial appendage. Surgical closure or enlargement of the defect is sometimes necessary to alleviate herniation. Tables Imaging Modalities in the Evaluation of Pericardial Disease

Echocardiography Advantages First-line imaging modality for initial diagnosis and follow-up of pericardial disease

Cardiac CT

Cardiac MR

Superior anatomical details; 3D post-processing and cine capabilities; less operator dependent

Better contrast resolution and superior tissue characterization; direct multiplanar and cine imaging; less operator dependent Low cost, safe, widely available, Visualization of entire heart and Visualization of entire heart and does not use ionizing pericardium, easy detection of and pericardium; detection radiation; quickly performed, pericardial calcification; detection and characterization of especially as bedside test in and characterization of extracardiac findings hemodynamically unstable extracardiac findings that may patients explain presenting symptom; best test to evaluate associated or causative lung findings, such as edema or cancer Limitations Operator dependent, with limited High cost, ionizing radiation, and More cost and time acoustic window and narrow field occasional need for iodinated consuming; contraindicated of view; technical difficulties in contrast; challenges in patients in patient with pacemaker or postcardiac surgery and with with tachycardia and irregular defibrillator and in patients patients who are obese or have heart beat; no capability for direct with glomerular filtration rate chronic obstructive pulmonary flow velocity quantification < 30 mL/min; detection of disease; limited tissue calcification can be characterization challenging P.5:5

Image Gallery

(Left) Lateral chest radiograph shows opacity corresponding to a pericardial effusion , which separates the retrosternal fat stripe (dark line parallel to the sternum, anterior to the effusion) and epicardial fat stripe (dark line behind the effusion), the “Oreo cookie” sign. Sagittal contrast-enhanced CT image shows a pericardial effusion separating the retrosternal fat stripe and epicardial fat stripe . (Right) Axial CECT shows high-density 376

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, consistent with hemopericardium.

(Left) Echocardiogram shows circumferential anechoic pericardial space with smooth epicardial and endocardial borders, suggesting uncomplicated pericardial effusion. (Right) Axial CTA shows large pericardial effusion with collapse of the right ventricle and some inversion of the anterior surface of the heart . Also seen are attenuated left atrium and reflux of contrast into the inferior vena cava and hepatic veins , consistent with tamponade physiology.

(Left) Lateral chest radiograph with median sternotomy for prior CABG and pericardial calcification is consistent with constrictive pericarditis in the appropriate clinical setting. (Right) Axial CECT image shows calcific pericarditis and tubular/bullet-like configuration of the ventricles, consistent with constrictive pericarditis. Although pericardial thickening and calcification support constriction, they are not diagnostic, and constriction may be present in their absence. P.5:6

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(Left) Short-axis PD T2 MR with fat saturation shows circumferential pericardial thickening . Minimal pericardial calcification seen on CT (not shown here) is not appreciated. (Right) Four-chamber view SSFP MR in the same patient shows pericardial thickening , tubular-shaped heart , and septal bounce (on cine sequence, not shown here), consistent with features of constrictive pericarditis. Ventricular interdependence can be assessed on coronal oblique free-breathing echo-planar MR.

(Left) Axial CECT shows thick pericardial calcifications . SSFP MR shows hypointensity corresponding to pericardial calcification, although less easy to characterize. In spite of calcific pericarditis, there are no morphologic features suggestive of constrictive pericarditis. (Right) CMR tagging sequence shows persistent continuity of tag lines throughout the cardiac cycle along the pericardial-myocardial interface , which is diagnostic of pericardial adhesions.

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(Left) Axial T2-weighted fast SE MR shows a bilobed right pericardial mass with homogeneous high signal intensity and thin smooth single septation. (Right) Axial gadolinium-enhanced T1-weighted MR with fat saturation in the same patient obtained at a similar level shows no enhancement of the mass and dark intrinsic signal similar to cerebrospinal fluid, which is indicative of a simple pericardial cyst. P.5:7

(Left) Coronal CT shows nodular thickening and enhancement of the pericardium in a patient with right lung cancer , consistent with pericardial metastatic disease. (Right) Axial CT shows heterogeneous, irregular, lobulated, heterogeneously enhancing large soft tissue mass involving the atrioventricular groove and pericardium in a patient with lymphoma. Given lymphoma elsewhere, this is considered secondary cardiac involvement. Primary pericardial lymphoma is rare.

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(Left) Axial T2WI FS MR shows large complex heterogeneous signal mass centered within the space between the heart and the overlying pericardial layers. (Right) Sagittal T1WI C+ MR in the same patient shows a mass centered anterior to the right ventricle and great vessels with mass effect displacing the chambers posteriorly. Heterogeneous enhancements with nonenhancing areas are suggestive of necrosis in this case of primary pericardial sarcoma.

(Left) Frontal radiograph demonstrates prominent convex deformity of the left atrial appendage secondary to partial absence of the pericardium. (Right) Axial CECT in the same patient shows interposition of lung tissue between the aorta and the main segment of the pulmonary artery , indicating the absence of the pericardium in this area. Note the prominence of the atrial appendage.

Pericardial Anatomy Pericardial Anatomy Suhny Abbara, MD, FSCCT TERMINOLOGY Synonyms  Parietal pericardium = fibrous pericardium (plus its inner layer, the serous pericardium) = often simply referred to as pericardium  Visceral pericardium = serous pericardium = epicardium Definitions  Pericardium is a double-layered sac of serous and fibrous membranes that is connected to the mediastinum, sternum, and diaphragm (outer layer), and envelops cardiac surfaces and proximal great vessels and venae cavae (inner layers)

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Sac contains small physiologic amount of fluid (15-50 mL) that enables nearly friction-free motion of the heart within mediastinum  Outer layer is composed of fibrous pericardium and parietal portion of serous pericardium o Resulting layer is up to 2 mm thick and is often simply referred to as pericardium o Opposing visceral serous pericardium that covers the heart is often referred to as epicardium  Serous layer of pericardium is formed by single layer of mesothelial cells IMAGING ANATOMY Overview  Epicardium covers the heart and epicardial fat layer within which coronary arteries and cardiac veins run; epicardium gives the heart the glistening appearance when pericardial sac is opened during surgery  At the pericardial reflections, serous pericardium folds upon itself and continues as parietal serous pericardium, which is fused with fibrous pericardium; these 2 layers form parietal pericardium or simply the pericardium (as opposed to the epicardium)  Pericardial reflections form potential spaces that are called sinuses, which have several extensions known as pericardial recesses GROSS ANATOMY Fibrous Pericardium  Fibrous pericardium, which is the outer layer of parietal pericardium, is composed of several interwoven layers of collagen fibers with few interspersed elastic fibrils; this leaves only limited capacity to stretch o Consequently, rapidly accumulating effusions may lead to cardiac compression and tamponade physiology, even if they are only moderate in size, whereas slowly accumulating effusions may become quite large but not lead to tamponade o Inner aspect of fibrous pericardium is lined with thin layer of serous pericardium Serous Pericardium  Serous pericardium lines both the heart and epicardial fat (epicardium) as well as the fibrous pericardium; it consists of single layer of mesothelial cells Pericardial Attachments  Fibrous pericardium interweaves with great vessel adventitia and is anchored to central tendon of diaphragm inferiorly and to sternum anteriorly via sternopericardial ligament  Epicardium is in direct continuity with cardiac fat layer (epicardial fat); pericardium is surrounded by fat anteriorly (pericardial fat) and posteriorly o Pericardial fat pad = accumulations of pericardial fat near left ventricular apex and cardiophrenic angles; may mimic masses on radiographs but are readily identified as benign fat on CT or MR Pericardial Sinuses  Reflection of pericardium posterior to atria forms the oblique sinus, which is a cul-de-sac that extends to the carina; pericardial reflection posterior to the aorta and pulmonary trunk and cranial to left atrium forms the transverse sinus  Sinuses connect with several recesses formed by pericardial reflections along the junction of right atrium and superior vena cava (post caval recess) and along pulmonary vein ostia (right and left pulmonary venous recesses) o Inferior aortic recess lies between ascending aorta and right atrium and extends to transverse sinus o Superior pericardial recess covers posterior right proximal 3 cm of aortic root and right pulmonary artery and extends to transverse sinus  Sinuses and recesses are potential spaces that become visible when they fill with fluid o Small amounts of physiologic fluid in sinuses may mimic adenopathy or mediastinal masses on CT o Pericardial fluid in superior pericardial recess may mimic aortic dissection or intramural hematoma on CT Pericardiophrenic Bundle  Space between mediastinal portion of parietal pleura and parietal pericardium contains a nerve and vascular bundle running in craniocaudal direction o Bundle contains phrenic nerves and pericardiophrenic artery and veins o It traverses mediastinum and extends to both right and left diaphragm o Surgical injury to this bundle may result in diaphragmatic paralysis or elevation ANATOMY IMAGING ISSUES Imaging Recommendations  Normal pericardial thickness on CT is 2 mm; abnormally thick pericardium > 3 mm may be associated with constriction, although not diagnostic o Of note, normal thickness pericardium does not exclude constriction 381

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CT is best test to identify pericardial calcifications MR is best test to identify pericardial adhesions; this is achieved by applying tag lines orthogonal to pericardium on cine imaging Imaging Pitfalls  Pockets of fluid within pericardial recesses and sinuses can be mistaken for mediastinal adenopathy or masses P.5:9

Image Gallery PERICARDIAL SAC WITH AND WITHOUT HEART

(Top) Anterior view of the heart and pericardium has portions of the anterior parietal pericardium removed to allow viewing of the heart and its glistening visceral pericardium. Note that the pericardial reflections are approximately 3 cm above the origins of the aorta and pulmonary arteries. Note coronary arteries, cardiac veins, and epicardial fat “shining through” the glistening epicardium (also referred to as visceral pericardium or epicardium). (Bottom) Anterior view shows the posterior portions of the parietal pericardium and its reflections with the heart removed (view from “inside” the pericardial space). Asterisk denotes the transverse sinus. P.5:10

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VISCERAL PERICARDIUM, POSTERIOR VIEW, PARIETAL PERICARDIUM REMOVED

Posterior graphic of the heart after removal of the parietal pericardium shows cut edges of the pericardial reflections at the pulmonary veins and venae cavae. Most of the heart is covered by the serous visceral pericardium. The space above the left atrial roof and below the pulmonary artery and posterior to the aortic root is termed the transverse sinus. After opening the pericardium, the surgeon may put a finger or instrument through the space, and occasionally a bypass graft is routed through this space. P.5:11

CROSS-SECTIONAL APPEARANCE OF PERICARDIUM

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(Top) Graphic shows an axial section at the level of the pulmonary artery bifurcation. The superior aortic recess is illustrated, which extends approximately 3 cm above the aortic root. (Middle) Graphic shows axial section at the level of the fossa ovalis. The pericardium covers nearly all surfaces of the heart. The parietal pericardium is directly attached to the parietal pleural laterally. The phrenic nerve, artery, and vein run in craniocaudal direction within the space between the pleura and pericardium. (Bottom) Graphic shows a sagittal section through the heart at the level of the right ventricular outflow tract. The pericardium separates the pericardial or mediastinal fat from the epicardial fat. The coronary arteries are embedded in the epicardial fat and are therefore also known as the epicardial arteries. P.5:12

PERICARDIAL ANATOMY ON AXIAL MDCT

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(Top) Axial contrast-enhanced cardiac CT at the level of the trachea just above the carina shows the most cephalad extent of the pericardium, the superior aortic recess. Small amounts of fluid in this recess may mimic pathology such as adenopathy, masses, and aortic dissection. (Middle) Axial contrast-enhanced cardiac CT at the level of the pulmonary trunk shows a small amount of fluid separating the epicardium from the parietal pericardium between the ascending aorta and pulmonary artery. (Bottom) Axial contrast-enhanced cardiac CT at the level of the left atrial appendage shows a small fluid collection posterior to the aorta and pulmonic valve. This fluid is within the transverse sinus, which is a potential space that can be used to route a bypass graft through. P.5:13

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(Top) Axial contrast-enhanced cardiac CT at the level of the left superior pulmonary vein shows the left anterior descending coronary artery and diagonal branch within the epicardial fat off the anterior interventricular groove, just posterior to the pericardial contour. (Middle) Axial contrast-enhanced cardiac CT at the level of the left ventricular outflow tract shows thin contour of pericardium separating the pericardial fat and the epicardial fat. Both the right atrioventricular groove (or sulcus) and the anterior interventricular groove are shown. (Bottom) Axial contrastenhanced cardiac CT at the level of the middle cardiac vein shows the epicardial fat of the posterior interventricular groove. P.5:14

PERICARDIAL ANATOMY ON BLACK BLOOD MR

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(Top) Sagittal FSE black blood MR shows the pericardial contour separating the pericardial fat (anterior, between sternum and pericardium) from the epicardial fat (between pericardium and myocardium/great vessels). In the absence of effusions or other pathology, both MR and CT cannot resolve the epicardium and pericardium as separate structures, and these therefore appear as 1 curvilinear line. (Middle) Left ventricular long-axis FSE MR shows pericardium as a curved line surrounding the heart. The visibility of the pericardium depends on the location and is best along the anterior cardiac surface (epicardial and pericardial fat on either side). Often, the pericardium is not visualized along the posterolateral and inferior walls of the left ventricle because of a paucity of pericardial fat at these locations. (Bottom) Four-chamber view FSE MR shows pericardium anteriorly, with poorly visible or nonvisible pericardium laterally due to absence of mediastinal or pericardial fat between the lung (black) and pericardium. P.5:15

PERICARDIAL ANATOMY ON WHITE BLOOD CINE & LGE IMAGING

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(Top) Axial SSFP white blood cine image shows pericardium anteriorly as a curved line separating anterior pericardial fat from epicardial fat. (Middle) Tagged gradient-echo cine images in different phases of the cardiac cycle show tag lines when they were recently deposited (top image) and later in the cardiac cycle (bottom image). If normal motion occurs, the tag lines move with the tissue in which they were deposited and appear to fracture or break the location where they traverse the pericardium, as shown here. (Bottom) Late gadolinium enhancement MR in left ventricular short axis shows normal black pericardium. The inversion time was optimized for nulling of left ventricular myocardial signal. Inflamed or infected pericardium enhances and will appear white.

Infectious Pericarditis Infectious Pericarditis John P. Lichtenberger, III, MD Key Facts Terminology  Pericarditis due to microbial agent Imaging  Radiography o Signs of pericardial effusion, calcification  CT o Best characterizes calcification or gas o Thickened, irregular pericardium o High-attenuation pericardial fluid 388

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Calcification in chronic pericarditis

MR

o Evaluates pericardial thickening/effusion o Evaluates signs of tamponade/constriction o STIR imaging may detect pericardial inflammation o Tagged cine T1-weighted GRE may demonstrate tethering of pericardium Top Differential Diagnoses  Iatrogenic pericarditis o Pericardiotomy, radiation therapy  Inflammatory pericarditis o Rheumatoid arthritis, systemic lupus erythematosus  Metabolic disorders o Renal failure  Neoplastic disease Clinical Issues  Pleuritic chest pain  Fever, tachycardia, dyspnea Diagnostic Checklist  Look for signs of tamponade and constriction  Pericardial calcifications may suggest chronic/remote infectious pericarditis  Enhancing pericardium separated by complex fluid

(Left) Anteroposterior chest radiograph of a patient with acute pericarditis and chest pain shows enlargement of the cardiac silhouette with globular “water bottle” morphology, typical for a large pericardial effusion. (Right) Axial CECT of a different patient with acute pericarditis shows thickening and enhancement of both the visceral and the parietal pericardial layers separated by pericardial effusion. Viral disease is the most common cause of infectious pericarditis.

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(Left) Lateral radiograph of a patient with acute pericarditis shows opacity separating the relatively lucent epicardial and anterior mediastinal fat, the “Oreo cookie” sign. The lateral chest radiograph is more sensitive for pericardial fluid and calcification than is the frontal radiograph. (Right) Sagittal CECT of the same patient shows the small circumferential pericardial effusion. CT allows direct evaluation of the entire pericardium and associated thoracic disease. P.5:17

TERMINOLOGY Synonyms  Pyopericardium, if bacterial Definitions  Pericarditis due to microbial agent IMAGING General Features  Best diagnostic clue o Typical imaging characteristics of pericardial effusion o Thickened and enhancing pericardium o Calcification in chronic pericarditis  Location o Diffuse involvement or focal loculated abscess  Size o Varying size of pericardial fluid or purulent material  Morphology o Loculations with enhancing septation may be present Radiographic Findings  Radiography o Radiographs may appear normal until pericardial fluid exceeds 250 mL o Pericardial calcifications o Pericardial effusion  Posteroanterior chest radiograph  Enlargement of cardiac silhouette  Flask- or water bottle-shaped cardiac silhouette  Lateral radiograph  “Sandwich” or “Oreo cookie” sign: Separation of lower density retrosternal pericardial fat from cardiac epicardial fat by higher density effusion CT Findings  NECT o Best characterizes calcification or gas o Thickened, irregular pericardium 390

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o o CECT o o o o

High-attenuation pericardial fluid may suggest purulent effusion, hemorrhage, neoplastic pericarditis Inflammatory stranding in adjacent mediastinal fat Mediastinal inflammation and associated abscess Separation of epicardium and pericardium Enhancing pericardium, septations, loculations Rarely gas bubbles from gas-producing organism or prior instrumentation May demonstrate features of tamponade  Mass effect on right heart or coronary sinus  Straightening or bowing of interventricular septum  Signs of elevated right heart pressure  Reflux of intravenous contrast into vena cava

MR Findings  T1WI o Similar findings compared to CT  T2WI o May not demonstrate bright fluid as motion may dephase protons  T1WI C+ o Enhancing pericardium and septations  SSFP cine o Quantifies pericardial effusion o Evaluates signs of tamponade physiology o Evaluates signs of elevated right heart pressure  Black blood SE o Evaluates pericardial thickening o STIR imaging may detect pericardial inflammation or associated masses  Tagged cine T1-weighted GRE o May demonstrate tethering of pericardium Echocardiographic Findings  Echocardiogram o Often 1st imaging modality employed o Effusions of varied size, ± septations o Rarely, contrast echoes within pericardium from gas-forming organisms o Tamponade in extreme cases o May be limited by acoustic windows o Difficult to image entire pericardium Angiographic Findings  Conventional o Invasive data usually acquired before percutaneous or open pericardiectomy o Features of tamponade Nuclear Medicine Findings  PET o FDG PET may demonstrate homogeneous uptake in pericardium if acute inflammation present o Intense FDG uptake associated with focal mass in pericardium may suggest neoplastic disease Imaging Recommendations  Best imaging tool o CT best evaluates calcific pericarditis, gas o MR and CT directly image entire pericardium  Distinguish thickening from fluid  Examine enhancement o Retrospectively gated cardiac CT and MR can evaluate physiologic complications  Tamponade, constrictive physiology DIFFERENTIAL DIAGNOSIS Idiopathic Pericarditis  26-86% of acute pericarditis  May be due to undiagnosed viral infection Iatrogenic Pericarditis  Radiation therapy: High incidence when > 4,000 rad 391

Diagnostic Imaging Cardiovascular  May develop post pericardiotomy in 10-40% of cardiac operations Inflammatory Pericarditis  Rheumatoid arthritis, systemic lupus erythematosus, scleroderma, rheumatic fever, sarcoidosis Metabolic Disorders  Renal failure o Dialysis decreases incidence  Hypothyroidism Cardiovascular Disorders  Myocardial infarction (MI) o Pericarditis complicates 5-8% of acute MIs o Dressler syndrome now rare P.5:18  Proximal extension of ascending aortic dissection and rupture into pericardium Neoplastic Disease  Hematogenous metastasis or direct extension  May demonstrate enhancing pericardial nodules and noncardiac metastatic foci  Pericardial cyst o Nonenhancing o Usually grows outward from parietal pericardium with no mass effect on heart  Intrapericardial teratoma o May demonstrate lipid level and coarse calcification Drug Reaction  Penicillin, procainamide, hydralazine, isoniazid, methysergide, phenytoin, anticoagulants Trauma  Penetrating trauma, esophageal rupture PATHOLOGY General Features  Etiology o Viral agent most common cause of acute pericarditis (1-10%)  Coxsackievirus B, adenovirus, influenza  Human immunodeficiency virus (HIV)  Hepatitis A and B o Pyogenic (bacterial) pericarditis uncommon  Most often Staphylococcus, Streptococcus, or gram-negative species o Tuberculous pericarditis  Suspected when insidious onset in high-risk groups  1-2% of patients with pulmonary disease  May exist without obvious pulmonary involvement  Increasing incidence in developing countries with high prevalence of HIV o Other uncommon infectious causes  Fungal, parasitic, lymphogranuloma venereum o Extension of myocardial abscess related to infectious endocarditis or mediastinal abscess o Secondary to esophageal or lung cancer invasion and subsequent infection  Acute pericarditis may be serous, fibrinous, sanguineous, hemorrhagic, or purulent  Chronic pericarditis may be serous, chylous or hemorrhagic (effusive), fibrous, adhesive, or calcific Gross Pathologic & Surgical Features  Features of normal pericardium o 2 pericardial layers: Visceral and parietal o 15-50 mL of pericardial fluid is normal  Exudate: Fluid with large amount of protein and cellular debris o Specific gravity > 1,020 g/L o “Bread and butter” appearance on gross pathology  Caseation requires exclusion of tuberculous pericarditis CLINICAL ISSUES Presentation  Most common signs/symptoms 392

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Pleuritic chest pain  Aggravated by thoracic motion (cough, respiration, supine position)  Relieved by upright position, leaning forward o Fever, tachycardia, dyspnea o Nonproductive cough o Pericardial friction rub  Best heard with patient leaning forward  May disappear when effusion increases o Muffled heart sounds in larger effusions o Fibrosis and constriction may be presenting signs of tuberculous pericarditis  Other signs/symptoms o Kussmaul sign: Paradoxical rise in jugular vein pressure with jugular vein distension o Pulsus paradoxus: > 10 mm Hg drop in systolic blood pressure and cardiac output  Clinical profile o Clinical features of myocardial, pericardial, and pulmonary disease overlap  Abdominal pain may be presenting symptom  ECG changes: Precordial friction rub may be triphasic or systolic and diastolic Natural History & Prognosis  Resolved with specific antimicrobial drugs  Purulent pericarditis almost always fatal if untreated o Mortality rate in treated patients: 40%  May progress to chronic effusive pericarditis  Viral myopericarditis, purulent pericarditis, and cat scratch disease may lead to pericardial constriction  Caseous pericarditis is most common indicator of constriction Treatment  Antimicrobial drugs  Pericardiocentesis for relief of tamponade  Surgical debridement in advanced cases DIAGNOSTIC CHECKLIST Consider  Pericardial fluid evaluation o Cell count + differential, stains, and culture for aerobic and anaerobic bacteria, acid-fast and fungal agents o Viral cultures and viral nucleic acid detection assays o Cytology to exclude neoplasm Image Interpretation Pearls  Enhancing pericardium separated by complex fluid  Pericardial calcifications may suggest chronic/remote infectious pericarditis  Look for signs of tamponade and constriction SELECTED REFERENCES 1. Mehrzad R et al: Pericardial involvement in diseases of the heart and other contiguous structures: part II: pericardial involvement in noncardiac contiguous disorders. Cardiology. 121(3):177-83, 2012 2. James OG et al: Utility of FDG PET/CT in inflammatory cardiovascular disease. Radiographics. 31(5):1271-86, 2011 3. Verhaert D et al: The role of multimodality imaging in the management of pericardial disease. Circ Cardiovasc Imaging. 3(3):333-43, 2010 4. Yared K et al: Multimodality imaging of pericardial diseases. JACC Cardiovasc Imaging. 3(6):650-60, 2010 P.5:19

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(Left) Short-axis LGE MR of a patient with acute pericarditis shows circumferential pericardial enhancement. MR directly images the entire pericardium in nonconventional planes and provides superior tissue characterization. (Right) Axial LGE MR of a 64-year-old woman with acute pericarditis and chest pain following a viral illness shows circumferential pericardial enhancement without significant effusion. MR can distinguish pericardial thickening and inflammation from simple pericardial fluid.

(Left) Composite image of posteroanterior (left) and lateral (right) chest radiographs of a patient with tuberculous pericarditis shows an arch of pericardial calcification . Pericardial calcification in the absence of prior cardiac surgery may warrant evaluation for tuberculosis in high-risk patients. (Right) Coronal CECT of the same patient confirms the pericardial origin of the calcific opacities and demonstrates coarse calcifications.

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(Left) Axial CECT of a patient with HIV and tuberculous pericarditis shows diffuse thickening and enhancement of the pericardial layers and pericardial and bilateral pleural effusions. A pericardial drain is in place. Tuberculous pericarditis may occur without pulmonary symptoms, particularly in HIV population. (Right) Axial CECT of a patient with pericarditis and pericardial effusion after partial pericardiectomy shows tubular morphology of the ventricles as seen in tamponade physiology.

Uremic Pericarditis Uremic Pericarditis Jonathan Hero Chung, MD Key Facts Terminology  Uremic pericarditis: Inflammation of pericardial lining related to end-stage renal failure  Dialysis-associated pericarditis: Pericarditis in those on dialysis Imaging  Radiography o Pericardial effusion: Flask- or bottle-shaped silhouette on AP image o Pericardial effusion: “Fat pad” or “Oreo cookie” sign on lateral image o Small pericardial effusions are usually not apparent  CT/MR o Even small pericardial effusions are well evaluated o Enhancement of pericardial lining may or may not be present o Tamponade physiology may be present Top Differential Diagnoses  Other causes of pericarditis  Aortic dissection  Volume overload  Myocardial infarction  Neoplastic pericarditis Pathology  Uncertain pathogenesis Clinical Issues  6-10% of patients with acute or chronic renal failure  Treatment o Intensified dialysis if hemodynamically insignificant o Pericardiocentesis if persistent or progressive effusion o Pericardial window for large, persistent, or recurrent effusion, purulent pericarditis, or tamponade

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(Left) Axial CECT shows circumferential, homogeneously fluid attenuation pericardial effusion with thickened, enhancing pericardium . Note the absence of pericardial masses or nodules as well as the absence of septations or material within effusion. (Courtesy A. Shabaan, MBBCh.) (Right) Axial CECT of the abdomen in the same patient shows peritoneal dialysis catheter in place, hinting that the pericardial effusion is due to uremic pericarditis.

(Left) Lateral radiograph shows fluid/soft tissue density outlined by both pericardial fat and epicardial fat , consistent with the “Oreo cookie” sign and diagnostic of a pericardial effusion. Bilateral pleural effusions are also present. (Right) Sagittal image from a chest CT correlates with the lateral radiograph, as pericardial fat and epicardial fat are separated from each other by the presence of simple pericardial fluid . Note pericardial and epicardial enhancement. P.5:21

TERMINOLOGY Definitions  Uremic pericarditis: Inflammation of pericardial lining related to end-stage renal failure  Dialysis-associated pericarditis: Pericarditis in those on dialysis IMAGING General Features  Best diagnostic clue o Thickened pericardium and effusion in patients with renal failure Radiographic Findings  Radiography o Pericardial effusion  Flask- or bottle-shaped silhouette on AP 396

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 “Fat pad” or “Oreo cookie” sign on lateral Small pericardial effusions or thickening not well evaluated on radiography

CT Findings  Pericardial thickening (> 1-2 mm)  Even small pericardial effusions are well evaluated  Enhancement of pericardial lining may or may not be present  Tamponade physiology may be present o Septal bounce: Paradoxical bouncing motion of interventricular septum initially directed toward and then away from left ventricle during early diastole o Flattening of anterior surface of heart (right ventricular free wall) o Enlarged systemic veins: Superior vena cava, inferior vena cava, hepatic and renal veins o Periportal edema Echocardiographic Findings  Echocardiogram o Persistent echo-free space between parietal and visceral pericardium throughout cardiac cycle  May show fibrinous strands o Tamponade physiology in extreme cases Other Modality Findings  MR similar to CT  Signs of tamponade may be present Imaging Recommendations  Best imaging tool o Echocardiography  Detection of physiologic effects of effusion DIFFERENTIAL DIAGNOSIS Other Causes of Pericarditis  Viral, bacterial, tuberculous pericarditis o Especially concerning in immunocompromised state Aortic Dissection  May cause hemorrhagic pericardial effusion and tamponade Volume Overload  Will produce transudative pericardial effusion Myocardial Infarction  Common in dialysis patients Neoplastic Pericarditis  Will not respond to dialysis PATHOLOGY General Features  Etiology o Uncertain pathogenesis  May be related to retained metabolites  Poor correlation with blood urea nitrogen  In some cases, may result from viral infection  Related to hemorrhagic diathesis  Clinical manifestations o Acute fibrinous pericarditis, effusion, tamponade Gross Pathologic & Surgical Features  Thickened highly vascular pericardium, adhesions, serous or hemorrhagic pericardial effusion CLINICAL ISSUES Presentation  Most common signs/symptoms o Pericarditis (sharp retrosternal pain aggravated by lying down and relieved by sitting up; friction rub) o Pericardial effusion (dyspnea if sizable) o Pericardial tamponade (tachycardia, hypotension, inspiratory jugular venous distention, paradoxical pulse)  Other signs/symptoms o Fever, palpitations, confusion Demographics 397

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Epidemiology o 6-10% of patients with acute or chronic renal failure Natural History & Prognosis  Quite variable, ranging from stable mild-moderate effusion without symptoms to frank tamponade  Constriction is uncommon though beginning to appear with long survival on dialysis  Some effusions persist despite dialysis Treatment  May respond to NSAIDs, corticosteroids, colchicine  Intensified dialysis if hemodynamically insignificant  Pericardiocentesis if persistent or progressive effusion  Pericardial window for large, persistent, or recurrent effusion, purulent pericarditis, or tamponade SELECTED REFERENCES 1. Walker CM et al: “Septal bounce”. J Thorac Imaging. 27(1):W1, 2012 2. Gavelli G et al: Thoracic complications in uremic patients and in patients undergoing dialytic treatment: state of the art. Eur Radiol. 7(5):708-17, 1997 3. Sever MS et al: Pericarditis following renal transplantation. Transplantation. 51(6):1229-32, 1991 4. Rostand SG et al: Pericarditis in end-stage renal disease. Cardiol Clin. 8(4):701-7, 1990 5. Spodick DH: Pericarditis in systemic diseases. Cardiol Clin. 8(4):709-16, 1990

Neoplastic Pericarditis Key Facts Terminology  Pericardial involvement with primary or secondary neoplasm Imaging  Radiography o Chest radiography findings of pericardial effusion o Mediastinal lymphadenopathy  Cardiac gated CTA o Best morphologic imaging, best spatial resolution o Pericardial effusion with diffuse or nodular pericardial thickening o Separation of thickened visceral and parietal pericardium by effusion  Cardiac MR o Ideal for functional analysis of constrictive physiology o Enhancing mass may be visible Top Differential Diagnoses  Myopericarditis o Infectious, inflammatory, or drug induced  Hemopericardium due to other etiologies  Pericardial cyst  Effects of treatment Pathology  Primary tumors of the pericardium: Angiosarcoma and other sarcomas  Most common neoplasms metastatic to pericardium: Lung, breast, melanoma, lymphoma Diagnostic Checklist  Malignant pericardial effusion is often 1st sign of pericardial metastatic disease  Assessment for signs of cardiac tamponade and coronary artery involvement

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(Left) Axial CECT of a patient with metastatic melanoma shows a pericardial mass invading the right atrium. A malignant pericardial effusion is present . Metastatic disease is further supported by multiple avidly enhancing subcutaneous masses, pulmonary nodules, and pleural disease. Metastatic disease is the most common cause of neoplastic pericarditis. (Right) Axial CECT of a patient with lung cancer shows a mass in the left lower lobe directly invading the pericardium.

(Left) Cardiac gated axial CTA of a patient with a malignant mediastinal mass shows thickening and enhancement of the pericardium , indicating pericardial invasion. Cardiac gated CT provides superior spatial resolution in cases of pericardial neoplastic disease. (Right) Axial CECT of a patient with thymic carcinoma shows both elevation and nodular slight thickening of the pericardium . These are useful signs when determining pericardial and cardiac involvement in metastatic disease. P.5:23

TERMINOLOGY Definitions  Pericardial involvement with primary or secondary neoplasm o Most frequently metastatic via direct invasion, lymphatic spread, or hemorrhagic spread IMAGING General Features  Best diagnostic clue o Pericardial effusion with diffuse or nodular pericardial thickening  May cause effusive-constrictive pericarditis

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May result from direct invasion of extracardiac mass or hematogenous spread directly to pericardium o Hemorrhagic effusion accompanying cardiac metastasis or primary cardiac tumor may be present without pericarditis  Morphology o Quite varied depending on tumor type Radiographic Findings  Radiography o Chest radiography findings of pericardial effusion  Flask-shaped cardiac silhouette in presence of significant effusion  Soft tissue surrounding heart or unusual cardiac contour  “Oreo cookie” sign on lateral radiography  Separation of mediastinal and subepicardial fat by stripe of fluid density o Mediastinal lymphadenopathy o Pleural effusions in 50% of cases o Other evidence of primary or metastatic disease may be suggestive CT Findings  NECT o Thickening ± irregularity of pericardial contour o High HU indicating hemorrhagic pericardial effusion o Calcifications are rare except in certain tumors  Osteosarcoma, angiosarcoma  Tumors with psammomatous calcification o Associated signs of malignancy  Lung and bone metastases  Lymphadenopathy, pleural effusion  CECT o Nodular enhancement of pericardial layers o Separation of thickened visceral and parietal pericardium by effusion o Invasion of epicardial or pericardial fat o May demonstrate pericardial invasion of extracardiac tumor o Straightening of right ventricular and left ventricular heart borders o Dilated superior vena cava (SVC), azygos vein, and inferior vena cava (IVC)  CTA o Gated CTA may demonstrate septal bounce o Typical features of pericardial effusion, tamponade, or thickened pericardium o Enhancing mass may be visible o Image characteristics may suggest hemopericardium MR Findings  T1WI o Spin-echo black blood images may demonstrate thickened nodular pericardium o Separation of visceral and parietal pericardium by fluid or blood o Metastases are usually of low signal intensity  Melanoma and hemorrhagic metastases may be hyperintense on T1WI  T2WI o High signal intensity relative to myocardium  T2* GRE o Functional images may demonstrate signs of pericardial constriction  Pericardial bounce  Flattening of right ventricle and shift of interatrial septum toward left ventricle  Dilated IVC and SVC  T1WI C+ o Enhancement of irregular and thickened epicardium and pericardium o Enhancing mass may be visible  Better assessment of extent of disease than with CT  Cardiac functional impairment can be detected and quantitated Echocardiographic Findings  Procedure of choice for initial evaluation of suspected pericardial effusion  Signs of tamponade: Right ventricular or atrial diastolic collapse 400

Diagnostic Imaging Cardiovascular  Can demonstrate studding of pericardium with tumor Angiographic Findings  Conventional o Left ventriculogram may show flattening of left ventricular border Nuclear Medicine Findings  PET o May demonstrate FDG uptake within pericardium  May also identify remote noncardiac primary malignancy or other metastases Imaging Recommendations  Best imaging tool o Echocardiography for initial evaluation o Cardiac gated CTA  Best morphologic imaging, best spatial resolution in true 3D volume data set  Will also allow limited functional assessment (septal bounce)  Best modality to demonstrate direct invasion from lung cancer or chest wall o Cardiac MR or echocardiography  Ideal for functional analysis of constrictive physiology  Due to acoustic window restrictions, echocardiography may not visualize entire pericardium DIFFERENTIAL DIAGNOSIS Myopericarditis  Infectious, inflammatory, or drug induced P.5:24  Enhancing, irregular pericardium and epicardial enhancement may mimic neoplastic disease  Calcifications may suggest tuberculosis  Pyopericardium may result in loculations or gas  Uremic pericarditis Hemopericardium Due to Other Etiologies  Traumatic, iatrogenic  Ruptured ascending aortic dissection Pericardial Cyst  May mimic loculated effusion  Homogeneous water attenuation  Well marginated, no soft tissue components Effects of Treatment  Drug- or radiation-induced pericardial thickening/nodularity o Radiation dose usually > 3,000 cGy o Common drugs include doxorubicin and cyclophosphamide PATHOLOGY General Features  Etiology o Primary tumors of pericardium  Angiosarcoma and other less common sarcomas  Mesothelioma  Fibroma, lipoma  Pheochromocytoma, neurofibroma, neuroblastoma  Teratoma: Benign tumor in infants and children o Metastatic disease  Most common neoplasms metastatic to pericardium: Lung, breast, melanoma, lymphoma  Melanoma (60% with pericardial involvement)  Hodgkin or non-Hodgkin lymphoma  Leukemia, myeloma  Direct invasion of mediastinal, pulmonary, chest-wall, or breast tumors  Malignant pericardial effusions overwhelmingly secondary to metastases  Cells obtained through pericardiocentesis confirm diagnosis  Pericardial biopsy frequently necessary 401

Diagnostic Imaging Cardiovascular Gross Pathologic & Surgical Features  > 90% are of epithelial origin (e.g., lung, breast) Microscopic Features  Immune markers can help discriminate among different cell types  Psammoma bodies in lung cancer, ovarian cancer CLINICAL ISSUES Presentation  Most common signs/symptoms o Often asymptomatic (50%) o Typically related to impaired cardiac function (30%) from pericardial effusion and tamponade  Hypotension and tachycardia o Arrhythmia common o Pleuritic chest pain, cough, dyspnea, edema  Other signs/symptoms o Signs of cardiac tamponade  Kussmaul sign: Increased distention of jugular veins with inspiration  Friedreich sign: Rapid diastolic descent of venous pulse  Pulsus paradoxus: Decrease of > 10 mm Hg in diastolic pressure on inspiration Demographics  Epidemiology o Melanoma has highest rate of cardiac metastases (46-71%) o 33% of pericardial metastases from lung cancer o 15% of pericardial metastases from hematologic malignancy o 1 in 3 patients with lung cancer has pericardial metastases at autopsy o 1 in 4 patients with malignant pericardial effusion has breast cancer o 1 in 4 patients with breast cancer has malignant pericardial effusion at autopsy Natural History & Prognosis  Very poor prognosis  > 80% die within 5 years of detection o About 1/3 die within a month of detection, usually from tamponade o Other causes of death: Congestive heart failure, coronary artery invasion, arrhythmia  Cardiac tamponade from pericardial effusion o Decreased cardiac output, progressive decrease in diastolic filling o Rapid accumulation poorly tolerated o Recurrent pericardial effusion in 50% of cases Treatment  Therapeutic pericardiocentesis with complete drainage  Pericardiotomy (percutaneous with balloon or surgical excision) to allow drainage into pleural space  Treatment of primary tumor  Extensive pericardial excision  Pericardial peritoneal shunt or continuous percutaneous drainage  Sclerosing treatment in rare cases DIAGNOSTIC CHECKLIST Image Interpretation Pearls  Malignant pericardial effusion is often 1st sign of pericardial metastatic disease  Assessment for signs of cardiac tamponade and coronary artery involvement SELECTED REFERENCES 1. Makis W et al: Spectrum of malignant pleural and pericardial disease on FDG PET/CT. AJR Am J Roentgenol. 198(3):678-85, 2012 2. Prakash P et al: Imaging findings of pericardial metastasis on chest computed tomography. J Comput Assist Tomogr. 34(4):554-8, 2010 3. Abbara S et al: Pericardial and myocardial disease. In Miller SW: Cardiac Imaging: The Requisites. Philadelphia: Elsevier Mosby. 245-283, 2005 P.5:25

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(Left) Posteroanterior chest radiograph of a patient with synovial sarcoma of the pericardium shows a mediastinal mass overlying and distorting the cardiac silhouette. (Right) Axial CECT of the same patient shows a heterogeneous, enhancing mass posteriorly displacing the heart and adjacent structures. A malignant pericardial effusion is present with enhancement of the pericardium. The pericardium is elevated by the mass , supporting an intrapericardial mass.

(Left) Axial T2 FSE MR image in the same patient with synovial sarcoma of the pericardium shows heterogeneous soft tissue and cystic components within the mass. The pericardium is elevated and thickened . (Right) LGE MR short axis to the left ventricle in the same patient shows intense peripheral enhancement of the mass, indicating a fibrous capsule without invasion of the right ventricular outflow tract. Multiplanar imaging is an advantage of MR in cases of pericardial masses.

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(Left) Axial CECT of an 18-year-old woman with a pericardial lipoma shows a fat attenuation mass oriented along the anterior interventricular groove with displacement of the left anterior descending coronary artery . (Right) Axial balanced SSFP MR image (left) of same patient shows that the lipoma is isoattenuating to subcutaneous fat without obvious invasion of adjacent structures. Oblique axial post-contrast T1 fat saturated MR image (right) confirms a fatty, nonenhancing mass.

Constrictive Pericarditis Constrictive Pericarditis John P. Lichtenberger, III, MD Key Facts Terminology  Abnormal thickening and adhesion of pericardium resulting in impaired ventricular filling Imaging  Imaging findings are most relevant when there is clinical evidence of physiologic constriction  CT: Best modality for pericardial calcification o Pericardial effusion/thickening (> 4-6 mm) o Waist-like narrowing of atrioventricular groove o Calcification is highly suggestive of constriction  MR: High sensitivity for distinguishing constrictive pericarditis from restrictive cardiomyopathy o Septal bounce: Paradoxical diastolic motion of interventricular septum Top Differential Diagnoses  Restrictive cardiomyopathy  Pericarditis without constriction Pathology  Causes include postmyocardial infarction, postradiation, postsurgical, postinfectious, post-traumatic, and idiopathic  In developed countries, most common etiologies are idiopathic (presumed viral) and post-CABG Clinical Issues  Symptoms of right heart failure  Surgical stripping of pericardium o Difficult to remove entire pericardium  Medical treatment is difficult and does not affect natural progression or prognosis of disease Diagnostic Checklist  Pericardial thickening, pericardial enhancement, and presence of calcifications  Thickening does not necessarily indicate constriction

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(Left) PA radiograph of a patient with uremic pericarditis shows subtle linear calcification along the inferior and right cardiac silhouette borders. Pericardial calcification is highly suggestive of pericardial constriction in a patient with constrictive physiology. (Right) Lateral radiograph of the same patient shows extensive pericardial calcification along the anterior and inferior borders of the cardiac silhouette. The lateral radiograph is more sensitive for pericardial calcification.

(Left) Axial NECT of a patient with constrictive pericarditis shows thick, irregular calcification in the atrioventricular groove causing waist-like narrowing and tubular configuration of the ventricles and biatrial enlargement. (Right) Short-axis late gadolinium enhancement MR in a patient with constrictive pericarditis shows delayed pericardial enhancement predominantly along the inferior surface of the heart, seen in pericardial inflammation or fibrosis. P.5:27

TERMINOLOGY Definitions  Abnormal thickening and adhesion of pericardium resulting in impaired ventricular filling  Associated findings: Tubular ventricular configuration and congestive heart failure IMAGING General Features  Best diagnostic clue o Pericardial disease in combination with heart failure  Pericardial calcifications are highly suggestive but not diagnostic of constrictive pericarditis  Thickness > 4-6 mm suggests but does not confirm pericardial constriction (normal < 2-3 mm) 405

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Associated signs of hepatic venous congestion, enlargement of atria, dilated superior/inferior vena cava and hepatic veins Ascites, pleural effusions, and pericardial effusion

 Location o Thickening may be diffuse or isolated over right atrium, right ventricle, or right atrioventricular groove o Sometimes isolated to right side of heart  Morphology o Reduced volume and narrow tubular configuration of right ventricle  May see prominent leftward convexity or sigmoid-shaped septum o Septal bounce on cine images o Biatrial enlargement Radiographic Findings  Radiography o Pericardial calcification  Linear or nodular  Typically diffuse, right sided, along atrioventricular groove or diaphragmatic surface  Best seen on lateral radiograph o Biatrial enlargement and pleural effusion in absence of pulmonary edema o Ascites may be suggested by elevation of hemidiaphragms CT Findings  NECT o Constrictive pericarditis findings  CT: Best imaging modality to detect pericardial calcification  Pericardial effusion/thickening (> 4-6 mm)  May be limited to right side of heart o Small effusion difficult to distinguish from thickening  Evaluate for attenuation characteristics of pericardial effusion  Exudative effusion as seen with infection, hemorrhage, neoplasm has increased attenuation  Transudative effusion has water attenuation (0-10 Hounsfield units) o Pericardial calcification highly suggestive of constriction o Pleural effusions, ascites, hepatic venous congestion  CECT o Pericardial enhancement may indicate active inflammatory process  Enhancement aids in distinguishing effusion from thickening o Atrial enlargement, dilation of vena cava  Cardiac gated CTA o Tubular ventricular configuration, straightened or sinusoidal interventricular septum o Waist-like narrowing of atrioventricular groove MR Findings  T1WI o Low signal intensity band encompassed by high signal intensity subepicardial and pericardial fat o Pericardial effusion of low signal intensity o Hemorrhagic effusion may be of high signal intensity  T2WI o Pericardium remains low signal intensity o Occasionally in subacute forms, thickened pericardium may have moderate to high signal intensity on spin-echo images o Effusion is of very high signal intensity unless complicated by hemorrhage or proteinaceous material  SSFP cine o MR has superior temporal resolution for detection of rapid hemodynamic processes  Septal bounce: Paradoxical diastolic motion of interventricular septum  Respirophasic variation in septal excursion indicating exaggerated ventricular interdependence o Tagging lines can help detect pericardial adhesion  Desaturation lines are applied to cine images  Image in multiple planes with tagging lines perpendicular to pericardium  Tagging lines which do not break during myocardial contraction suggest adhesion  Late gadolinium enhancement 

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Can detect pericardial enhancement  Related to acute/subacute inflammation or fibrous thickening o Also very useful to detect myocardial disease, which may indicate restrictive cardiomyopathy  MR is more sensitive in distinguishing pericardial effusion from thickening o Calcification may appear as signal void  MR: High sensitivity for distinguishing constrictive pericarditis from restrictive cardiomyopathy  Echoplanar free breathing cine MR may demonstrate respiratory ventricular interdependence Echocardiographic Findings  Primary diagnostic tool o Early diastolic filling becomes rapid with elevation and equalization of diastolic pressures in all cardiac chambers o Restriction of late diastolic filling o Septal bounce and inferior vena cava plethora with absent inspiratory variation o Equalization of atrial and ventricular pressures  Suboptimal in demonstration of pericardial thickening o Transesophageal echo allows better visualization of pericardium o Doppler inflow/outflow changes with respiration Imaging Recommendations  Best imaging tool P.5:28

o o

Imaging findings are most relevant when there is clinical evidence of constrictive physiology Echocardiography is primary tool to investigate physiologic changes of pericardium, although limited in some cases o CT and MR are useful to directly examine entire pericardium o CT is best tool to identify pericardial calcification o MR is more useful to distinguish constrictive pericarditis vs. restrictive cardiomyopathy o Cardiac catheter for physiology (R & L catheter)  Protocol advice o Perform MR and CT scans without and with contrast to assess for pericardial enhancement DIFFERENTIAL DIAGNOSIS Myocardial Calcification  Pericardial o Usually right sided (less cardiac motion) o Diffuse and extensive, may be nodular o Spares left atrium and apex o Affects atrioventricular (AV) groove  Myocardial o Usually left sided, in left ventricular wall o Focal, usually linear o Apex is typical location o Spares AV groove Pericarditis Without Constriction  Distinction is made based on physiologic changes  Constriction may be transient after acute pericarditis Restrictive Cardiomyopathy  Similar physiologic changes by echocardiography and cardiac catheterization  Look for associated myocardial thickening and enhancement as seen with sarcoidosis, amyloidosis, hypertropic cardiomyopathy, or lymphoma  LGE MR is extremely helpful in detecting hyperenhancement within myocardium related to restrictive cardiomyopathy Neoplasm  Metastases usually cause effusion, not masses o Focal or multifocal areas of enhancing pericardium suggest metastatic disease, especially in face of known primary  Primary tumors are rare (sarcomas, large bulky tumors) Pericardial Tamponade 407

Diagnostic Imaging Cardiovascular  Large accumulation of fluid within pericardium (hemorrhage, inflammatory process, effusion) PATHOLOGY General Features  Etiology o Caused by injury, iatrogenic, or idiopathic processes  In developed countries, most common etiologies are idiopathic (presumed viral) and postCABG  In developing world, infectious etiologies (tuberculosis has highest total incidence) o Infectious: Viruses (Coxsackie B, influenza), bacteria, tuberculosis, fungi, or parasites o Metabolic: Uremia o Inflammatory: Systemic lupus erythematosus, rheumatoid arthritis o Neoplastic: Metastasis  Normal pericardial anatomy o Usually 2 mm thickness o Lies between variable amounts of epicardial and pericardial fat o Has fibrous and serous components o Fibrous elements are attached to diaphragm, costal cartilage, and sternum o Serous element (thin mesothelial layer) is adjacent to heart o Intervening potential space usually contains 15-50 mL fluid Gross Pathologic & Surgical Features  > 50% of cases with pericardial calcification will have constrictive pericarditis CLINICAL ISSUES Presentation  Most common signs/symptoms o Symptoms of right heart failure  Dyspnea, orthopnea  May present with hepatomegaly, ascites o Symptoms are often vague with insidious onset o Kussmaul sign: Increased jugular venous pressure during inspiration o Both constrictive and restrictive physiology may be present Treatment  Surgical stripping of pericardium o Entire pericardium is difficult to remove  Medical treatment is difficult and does not affect natural progression or prognosis of disease  Pericardial constriction may recur despite treatment DIAGNOSTIC CHECKLIST Consider  Assessing both morphologic (pericardial thickness) and physiologic parameters (septal bounce, ventricular interdependence) Image Interpretation Pearls  Pericardial thickening, pericardial enhancement, and presence of calcifications  Thickening does not necessarily indicate constrictive disease SELECTED REFERENCES 1. Peebles CR et al: Pericardial disease—anatomy and function. Br J Radiol. 84 Spec No 3:S324-37, 2011 2. Rajiah P: Cardiac MRI: Part 2, pericardial diseases. AJR Am J Roentgenol. 197(4):W621-34, 2011 3. Verhaert D et al: The role of multimodality imaging in the management of pericardial disease. Circ Cardiovasc Imaging. 3(3):333-43, 2010 4. Yared K et al: Multimodality imaging of pericardial diseases. JACC Cardiovasc Imaging. 3(6):650-60, 2010 5. Bogaert J et al: Cardiovascular magnetic resonance in pericardial diseases. J Cardiovasc Magn Reson. 11:14, 2009 P.5:29

Image Gallery

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(Left) Short-axis inversion recovery FSE MR of a patient with constrictive pericarditis shows intermediate signal intensity pericardium between epicardial and mediastinal fat, indicating circumferential pericardial thickening . The normal pericardial thickness is 2 mm. (Right) Four-chamber T1WI MR with gadolinium in the same patient shows delayed enhancement of the pericardium along the left ventricle and right atrium, indicating fibrosis or inflammation. Biatrial enlargement is also present.

(Left) Short-axis balanced SSFP shows constrictive pericarditis and transient straightening of the interventricular septum that occurs during diastolic filling and results in a “septal bounce.” When exacerbated during respiration, this represents exaggerated ventricular interdependence in constrictive physiology. (Right) Four-chamber balanced SSFP of the same patient shows abnormal bowing of the interventricular septum toward the left ventricle at the basal and mid levels.

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(Left) Axial GRE MR with myocardial tagging of a patient with constrictive pericarditis shows pericardial adhesions evidenced by failure of myocardial tagging lines to break normally during cardiac contraction . Tagging lines are desaturation lines imposed during image acquisition. (Right) Parasternal long-axis GRE MR with myocardial tagging in the same patient shows adhesions near the cardiac apex . Imaging in multiple planes is important to adequately evaluate for pericardial adhesions.

Pericardial Cyst Pericardial Cyst Suhny Abbara, MD, FSCCT Cameron Hassani, MD Key Facts Imaging  Smoothly marginated rounded mass  Unilocular in 80-90%, multiloculated in 10-20%  Most commonly adjacent to right cardiophrenic (CP) angle o Right CP angle in 75% o 2nd most common location is left CP angle o But may occur anywhere in mediastinum around heart  Round mass at cardiophrenic angle on radiographs o Sharp, smooth contours o Partly spherical with incomplete borders  Fluid attenuation on CT o < 10 HU  Water signal intensity on MR o T1: Homogeneous low or intermediate signal intensity o T2: Homogeneous high signal intensity  No internal enhancement  Limited imaging protocol required o MR: Axial and coronal T1WI and T1 C+; axial and coronal T2WI o CT: Axial CT with contrast Pathology  Benign cyst of mediastinum Clinical Issues  Generally incidental imaging finding requiring no treatment  No literature to support percutaneous drainage Diagnostic Checklist  T2-intense, T1-hypointense mass without septations in right costophrenic angle is diagnostic of pericardial cyst

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(Left) Posteroanterior radiograph demonstrates a rounded mass at the left cardiophrenic angle that is smoothly marginated and contiguous with the left heart border. (Right) Lateral radiograph confirms the position of the mass near the left ventricular apex. It appears smoothly marginated within the left cardiophrenic angle and contiguous with the left heart border. No calcification or fluid/lipid levels are present.

(Left) Coronal CECT demonstrates a rounded mass that abuts the lateral left ventricle . This is a homogeneous, fluid-attenuation mass with no enhancement. Note a clean fat plane separating the mass from the left ventricle, which represents the normal epicardial fat. (Right) Axial CECT shows a rounded fluid-attenuation nonenhancing mass contiguous with pericardium but separated from myocardium by epicardial fat. These findings are diagnostic for a pericardial cyst. P.5:31

TERMINOLOGY Definitions  Anomalous fluid-containing mass that abuts the heart  Embryologic defect in coelomic cavity development or sequela of pericarditis IMAGING General Features  Best diagnostic clue o Smoothly marginated rounded mass adjacent to heart at costophrenic (CP) angles o Most commonly, right anterior costophrenic angle o Fluid attenuation on CT o Water signal intensity on MR 411

Diagnostic Imaging Cardiovascular o Unilocular in 80-90%; multiloculated in 10-20% Location o CP angle  Right: 75%  Left: 10-40%  Size o 2-30 cm in diameter  Morphology o Smoothly marginated o Rounded, teardrop-shaped o May change shape with cardiac cycle o May prolapse into pleural fissures Radiographic Findings  Radiography o Round mass at right or left cardiophrenic angle  Sharp, smooth contours  Partly spherical with incomplete borders (silhouette by heart) o May rarely occur in mediastinum distant from CP angle  In these cases, difficult to distinguish pericardial cyst from bronchogenic or thymic cyst o May change shape with body positioning, respiration, or cardiac cycle CT Findings  NECT o Smoothly marginated o Water attenuation (< 10 HU), usually no septations o Usually at CP angle, especially the right o Noncalcified o Wall imperceptible or thin  CECT o No internal enhancement o No wall enhancement MR Findings  T1WI o Uniform low or intermediate signal intensity (SI) o Occasionally may contain highly proteinaceous fluid, which may have high SI on T1WI  T2WI o Homogeneous high SI (follows that of water)  T1WI C+ o No internal enhancement o No rim enhancement  MR findings are diagnostic, generally requiring no further intervention  Phase-contrast imaging may detect slow internal flow if communicating with pericardial space Echocardiographic Findings  Anechoic space between epicardium and parietal pericardium Imaging Recommendations  Best imaging tool o Echocardiography or MR  Protocol advice o Limited protocol needed  Axial and coronal T1WI and T1 C+  Axial and coronal T2WI  Coronal imaging helpful to demonstrate relationship to heart and pericardium  Short-axis and 4-chamber planes not necessary  Echocardiography primary tool to investigate pericardium o Anechoic in appearance o High sensitivity and ability to differentiate solid from cystic masses o Defines relationships with cardiac chambers  CT and MR useful to o Examine entire pericardium 

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Diagnostic Imaging Cardiovascular o Distinguish myocardial from pericardial disease o Further characterize pericardial masses DIFFERENTIAL DIAGNOSIS Loculated Pleural Effusion  Fluid density at CT  Look for other loculations or free effusion  Enhancing septations may be present  History is pertinent o More common postoperatively Bronchogenic Cyst  Same imaging characteristics as pericardial cyst  Most commonly located in middle mediastinum around carina  When infected or containing secretions, may appear as solid tumor or may have air-fluid level Hematoma  MR particularly useful  Acutely demonstrates homogeneous high SI on T1WI and T2WI  Subacutely shows heterogeneous SI and areas of high SI on T1WI and T2WI  Chronically may show dark peripheral rim and low SI areas that may represent calcification, fibrosis, or hemosiderin deposition on T1WI  High SI areas on T1WI or T2WI may correspond to hemorrhagic fluid  No enhancement on T1 C+ Pericardial Fat Pad  Echo-free space may be seen by echocardiography o May be difficult to distinguish from pericardial fluid  Distinguishing feature: Fat density on CT Morgagni Hernia  Bowel or mesenteric fat in anterior hernia sac P.5:32

Enlarged Pericardial Lymph Nodes  Mantle radiation therapy: Cardiac blockers used to protect heart, area may be undertreated o “Fat pad” sign: Enlarging recurrent nodes from lymphoma in undertreated pericardial lymph nodes o Appearance or enlargement of “fat pad” heralds development of adenopathy o Nodes may be irradiated since field was blocked initially  May fill CP angle on frontal chest radiograph  On lateral view, may be retrosternal or at level of inferior vena cava or phrenic nerve Thymic Cysts or Thymolipoma  Cysts have fluid density at CT or MR  Thymolipoma contains fat  Thymus usually separable from pericardium Esophageal Duplication Cyst  Imaging characteristics identical to pericardial cyst  Adjacent to esophagus; majority are cervical Bronchogenic Carcinoma  Separate from pericardium at CT  Bronchogenic carcinoma can directly extend into pericardium  Effusion and irregularly thickened pericardium or pericardial mass Pericardial Metastases  Lung and breast cancers are most common  Effusion and irregularly thickened pericardium or pericardial mass  Enhancement is common on CT or MR  Most have low SI on T1WI and high SI on T2WI Neurofibroma  May cause CP angle mass  Generally solid but may have cystic components  Enhancement internally on CT or MR Hydatid Cyst 413

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Cystic mass with well-defined edges Internal trabeculations correspond to daughter membranes May be pericardial or intramyocardial May appear as solid mass if cyst is replaced by necrotic matter o Contains membrane residues and granulomatous foreign-body inflammatory reaction Pancreatic Pseudocyst  History is pertinent  Look for peripancreatic inflammatory changes and fluid collections  Usually extends through esophageal hiatus PATHOLOGY General Features  Etiology o Anomalous outpouching of parietal pericardium o Occurs by 4th week of gestation o Occurs as coalescing spaces form intraembryonic body cavity  Benign cyst of mediastinum Gross Pathologic & Surgical Features  Invariably connected to pericardium  Only a few show visible communication with pericardial sac Microscopic Features  Fibrous tissue lined by single layer of bland mesothelium  Differentiate from bronchogenic cyst and esophageal duplication cyst by cell lining o Absence of bronchial or gastrointestinal epithelium, respectively CLINICAL ISSUES Presentation  Most common signs/symptoms o Usually asymptomatic incidental finding o Prevalence: 1 in 100,000  Other signs/symptoms o If symptomatic, presents with chest pain, dyspnea, and cough  Symptoms secondary to large size and mass effect o Pericardial tamponade may rarely occur Demographics  Age o 30-50 years of age Treatment  Generally incidental radiographic finding requiring no treatment  Surgery if complicated by o Chest pain o Tamponade o Mistaken for malignancy  No literature to support percutaneous drainage DIAGNOSTIC CHECKLIST Consider  CT is often diagnostic  MR is considered imaging gold standard Image Interpretation Pearls  T2-intense, T1-hypointense mass without septations in right costophrenic angle is diagnostic of pericardial cyst SELECTED REFERENCES 1. Nijveldt R et al: Pericardial cyst. Lancet. 365(9475):1960, 2005 2. Guven A et al: A case of asymptomatic cardiopericardial hydatid cyst. Jpn Heart J. 45(3):541-5, 2004 3. Heirigs R et al: Images in cardiology: Pericardial cyst. Clin Cardiol. 27(9):507, 2004 4. Oyama N et al: Computed tomography and magnetic resonance imaging of the pericardium: anatomy and pathology. Magn Reson Med Sci. 3(3):145-52, 2004 5. Kim JH et al: Cystic tumors in the anterior mediastinum. Radiologic-pathological correlation. J Comput Assist Tomogr. 27(5):714-23, 2003 6. Wang ZJ et al: CT and MR imaging of pericardial disease. Radiographics. 23 Spec No:S167-80, 2003 414

Diagnostic Imaging Cardiovascular 7. Breen JF: Imaging of the pericardium. J Thorac Imaging. 16(1):47-54, 2001 P.5:33

Image Gallery

(Left) Anteroposterior radiograph demonstrates a rounded mass in the right cardiophrenic angle contiguous with the right heart border . (Right) Axial T2WI MR demonstrates a lobulated mass in the mediastinum at the right cardiophrenic angle, which shows homogeneously high T2 signal intensity with a single thin smooth septation . The mass broadly adheres to the pericardium. The appearance and location are characteristic for pericardial cysts.

(Left) Axial T1WI MR in a different patient demonstrates a lobulated mass at the right costophrenic angle, which shows a homogeneously low signal on T1-weighted images . No signs of invasion exist, and broad adherence to the pericardium is present. (Right) Axial T1WI C+ MR post-contrast images demonstrate absence of enhancement of the mass or its walls, compatible with a pericardial cyst .

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(Left) Axial T2WI FSE MR in the same patient demonstrates homogeneous high T2 signal consistent with fluid . Note that the signal intensity of the cyst is similar to that of cerebrospinal fluid (allowing for general variation of signal strength within the image), which can be used as an internal reference for fluid signal intensity. (Right) Coronal T2WI FSE MR in the same patient localizes the lesion to the right cardiophrenic angle .

Absent Pericardium Key Facts Terminology  Congenital absence of pericardium; may be partial or complete right, complete left, or complete Imaging  Radiography o Lung interposition between pulmonary trunk and aortic arch o Lung interposition between left hemidiaphragm and base of heart o Conspicuous left atrial appendage o Leftward shift of cardiac silhouette  CT: Leftward shift and rotation of heart o Absence of visible pericardium in affected region  MR: Absence of hypointense pericardial line o Excessive mobility of myocardium o Large difference in heart volume between end-systole and end-diastole in affected patients Top Differential Diagnoses  Pericardial cyst  Pericardial effusion  Loculated pleural effusion  Left ventricular aneurysm Pathology  Interruption of vascular supply to developing pericardium during embryogenesis Clinical Issues  Most complete defects are clinically insignificant  Foramen-type defects (subtype of partial pericardial absence defects) may be lethal  Treatment o Surgical closure of pericardial defect o Enlargement of pericardial defect to prevent strangulation of heart

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(Left) AP chest radiograph in a patient with absence of the left pericardium shows that the heart is shifted leftward, and the lung can be seen outlining the top of the pulmonic trunk between the pulmonary artery and the aortic knob. (Right) Axial CECT in a different patient with total pericardial absence demonstrates leftward and clockwise rotation of the heart. Note the absence of visible pericardium. Also note the unusual position of the left ventricle with the apex pointing posteriorly.

(Left) Axial CECT in a patient with congenital absence of the left pericardium shows leftward rotation of the heart and great vessels. Normally, the ascending aorta and pulmonic trunk are intrapericardial, but the lung may be interposed due to pericardial absence. (Right) Axial CECT of the same patient demonstrates leftward rotation and shift of the heart resulting in the right and left ventricles broadly abutting the left lateral chest wall. Note that the right pericardium is visible , but the left pericardium is absent. P.5:35

TERMINOLOGY Definitions  Congenital absence of pericardium; may be partial or complete right, complete left, or complete IMAGING General Features  Best diagnostic clue o Lack of visible pericardium along lateral left ventricular wall  Location o Partial defects usually occur along lateral left ventricular wall but may occur anywhere Radiographic Findings 417

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Radiography o Lung interposition between pulmonary trunk and aortic arch o Lung interposition between left hemidiaphragm and base of heart o “Snoopy” sign in complete absence of pericardium  Leftward shift and rounding of cardiac silhouette (“Snoopy's nose”)  May also be seen in partial absence of left pericardium  May not be present in younger patients with complete absence  Convex prominent left atrial appendage (“Snoopy's ear”)  Common in partial absence of left pericardium CT Findings  NECT o Lung interposition between pulmonary trunk and ascending aorta o Leftward shift and levorotation of heart o Absence of visible pericardium in affected region MR Findings  Absence of hypointense pericardial line  Excessive myocardial mobility, especially at apex  Large difference between end-systolic and end-diastolic volumes Echocardiographic Findings  Echocardiogram o Enlargement of left atrial appendage o Hypermobility of heart with swinging heart motion DIFFERENTIAL DIAGNOSIS Pericardial Cyst  Cardiophrenic angle mass abutting heart  Imperceptible wall  Water attenuation on CT, follows fluid signal on MR Pericardial Effusion  Globular symmetric enlargement of cardiopericardial silhouette on frontal chest radiography: “Water bottle” sign  > 2 mm water density stripe between retrosternal and subepicardial fat on lateral chest radiography o “Fat pad” sign or “Oreo cookie” sign Loculated Pleural Effusion  Usually can be separated from uninvolved pericardium  Typically water attenuation on CT Left Ventricular Aneurysm  Rare complication of myocardial infarction  Calcification may be present PATHOLOGY General Features  Etiology o Interruption of vascular supply to developing pericardium during embryogenesis  Associated abnormalities o Atrial septal defect, patent ductus arteriosus, mitral valve stenosis, and tetralogy of Fallot Staging, Grading, & Classification  2/3 are isolated cases  1/3 are associated with other congenital abnormalities o Cardiac: Bicuspid aortic valve, septal defects, tetralogy of Fallot, mitral stenosis, persistent ductus arteriosus o Extracardiac: Pectus excavatum deformity, pulmonary sequestration, diaphragmatic hernias CLINICAL ISSUES Presentation  Most common signs/symptoms o Complete absence: Usually asymptomatic o Partial absence: Nonexertional paroxysmal chest pain, tachycardia, palpitations, death  Symptoms due to herniation of parts of myocardium while other parts remain fixed Demographics  Gender: 70% male 418

Diagnostic Imaging Cardiovascular  Prevalence: 0.002-0.004% Natural History & Prognosis  Most complete defects are clinically insignificant  Subtype of partial absence may be lethal o Foramen-type defects may cause herniation of left atrial appendage or left ventricle that results in strangulation of myocardium Treatment  Surgical o Closure of pericardial defect o Enlargement of pericardial defect to prevent strangulation of heart DIAGNOSTIC CHECKLIST Consider  Absence of pericardium when there is lung interposition between pulmonary trunk and aortic arch, particularly if associated with left shift of heart SELECTED REFERENCES 1. Psychidis-Papakyritsis P et al: Functional MRI of congenital absence of the pericardium. AJR Am J Roentgenol. 189(6):W312-4, 2007

Pericardial Effusion Pericardial Effusion Brett W. Carter, MD Key Facts Terminology  Increased amount of fluid in pericardial space Imaging  Radiography o Frontal: “Water bottle” sign; globular enlargement of cardiopericardial silhouette o Lateral: “Fat pad” sign; pericardial fluid outlined by surrounding fat  CT o Water attenuation fluid: Uncomplicated effusion o High-attenuation fluid: Hemorrhage, purulent fluid, malignancy o Associated pericardial thickening and calcification o Cardiac chambers: Constriction and tamponade  MR: Assessment of complicated effusion o 93% accuracy for constrictive pericarditis  Echocardiography: Imaging modality of choice Top Differential Diagnoses  Pericardial cyst  Pericardial malignancy  Dilated cardiomyopathy Clinical Issues  Signs/symptoms o May be asymptomatic o Chest pain, friction rub o Cardiac tamponade: Rate of fluid accumulation is more significant than volume or composition  Treatment o Small effusions may not require treatment o Increased hemodialysis in chronic renal failure o Anti-inflammatory agents for acute idiopathic/viral pericarditis o Percutaneous or surgical drainage o Emergent management of tamponade

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(Left) Graphic shows features of pericardial effusion. Pericardial fluid is located in the potential space between the serous layers of the parietal pericardium and visceral pericardium or epicardium . (Right) Axial CECT of a patient with volume overload demonstrates a low-attenuation pericardial effusion . Note the left pleural effusion and the loculated pleural fluid along the right posterior mediastinum.

(Left) Posteroanterior chest radiograph of a patient with congestive heart failure demonstrates enlargement of the cardiac silhouette and bilateral pleural effusions . (Right) Lateral chest radiograph of the same patient shows a pericardial effusion manifesting as the “fat pad” sign. A water-attenuation stripe between the retrosternal mediastinal fat (also known as pericardial fat) and the subepicardial fat represents a pericardial effusion. P.5:37

TERMINOLOGY Definitions  Abnormal increase of fluid within pericardial sac  Cardiopericardial silhouette: Combined pericardial and cardiac silhouettes on radiography IMAGING General Features  Best diagnostic clue o Radiography: “Fat pad” sign on lateral radiograph o CT/MR: Fluid in pericardial space  Location o CT and MR  Small effusion: Posterior location; along left ventricle and left atrium 420

Diagnostic Imaging Cardiovascular  Large to moderate effusion: Anterior location; along right ventricle  Very large effusion: Around heart  Anatomic considerations o Pericardium surrounds heart and portions of pulmonary trunk, vena cava, and ascending aorta o Fibrous pericardium: Defines anatomic middle mediastinum o Serous pericardium: Within fibrous pericardium  Serous visceral pericardium: Epicardium; lines heart  Serous parietal pericardium: Lines fibrous pericardium  2 apposed pericardial layers with intervening potential (pericardial) space  Normally contains 15-50 mL of fluid  Normal pericardium o Radiography: Not visible o CT: Thin soft tissue linear structure; 0.7-2 mm thick o MR: Thin low-signal linear structure on T1WI & T2WI o CT and MR  Pericardium between retrosternal mediastinal and subepicardial fat  No distinction between serous and fibrous pericardial layers is possible  Frequent visualization of small amount of physiologic fluid and fluid-filled pericardial sinuses and recesses Radiographic Findings  Frontal chest radiograph o Moderately large (> 250 mL) pericardial effusion  “Water bottle” sign  Globular symmetric enlargement of cardiopericardial silhouette  Normal superior mediastinum o Documentation of slow or rapid cardiopericardial silhouette enlargement on serial radiography  Lateral chest radiograph o “Fat pad” sign: Also known as “Oreo cookie” sign, “sandwich” sign, or “bun” sign  > 2 mm water density stripe between retrosternal & subepicardial fat  > 200 mL of fluid: Visualization of cardiopericardial silhouette enlargement CT Findings  NECT o Direct assessment of pericardial abnormalities o Water-attenuation pericardial fluid  Heart failure, renal failure, malignancy o High-attenuation pericardial fluid  Hemorrhage, purulent effusion, malignancy  Hemopericardium: Attenuation is initially high but decreases over time o High sensitivity for associated pericardial thickening and calcification  CECT o Assessment for thickening, nodules, masses o Enhancement of serous pericardium and pericardial thickening from inflammation  Associated infiltration of mediastinal fat o Assessment of cardiac chambers  Signs of constriction: Tubular ventricles, flattened/sigmoid interventricular septum o Signs of cardiac tamponade  Flattening of anterior surface of heart and right cardiac chambers  Angulation or bowing of interventricular septum  Enlarged vena cava  Periportal edema  Reflux of contrast into inferior vena cava, azygos vein, &/or hepatic or renal veins  Compression of coronary sinus MR Findings  General o Uncomplicated effusion  T1WI: Hypointense; T2WI: Hyperintense o Complicated effusion: Septations, debris o Hemorrhagic effusion  T1WI: Hyperintense; T2WI: Hypointense 421

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Hemopericardium  Acute phase: Homogeneous hyperintensity  Subacute phase (1-4 weeks): Heterogeneous signal, foci of hyperintensity on T1WI and T2WI  Chronic phase (> 4 weeks): Hypointense foci (calcification, fibrosis), dark peripheral rim  No contrast enhancement o Assessment of pericardium and cardiac chambers to exclude constriction  MR: 93% accuracy for differentiation between constrictive pericarditis (pericardial thickening of > 4 mm) and restrictive cardiomyopathy Ultrasonographic Findings  High sensitivity for pericardial fluid o Echo-free space between pericardial layers o Decreased parietal pericardial motion  Assessment of constrictive pericarditis  Assessment of suspected tamponade o Mass effect  Diastolic compression/collapse of right heart chambers  Abnormal cardiac filling  Compression of pulmonary trunk and thoracic inferior vena cava o Abnormal motion  Lack of inspiratory collapse of dilated inferior vena cava  Cardiac swing within pericardium  Doppler flow velocity paradoxus: Respiratory variation in Doppler velocities  Paradoxical motion of interventricular septum P.5:38

Imaging Recommendations  Best imaging tool o Echocardiography: Modality of choice for pericardial imaging o CT/MR: Evaluation of complications of pericardial effusion; hemorrhage; loculation DIFFERENTIAL DIAGNOSIS Pericardial Cyst  Focal water attenuation cyst abutting pericardium  May mimic loculated pericardial effusion Pericardial Malignancy  10-12% of patients with malignancy at autopsy  1/3 of cases: Lung cancer  Pericardial nodular thickening, effusion, enhancement, mass Dilated Cardiomyopathy  Marked cardiomegaly  May mimic pericardial effusion PATHOLOGY General Features  Etiology o Obstruction of lymphatic or venous drainage o Myocardial infarction and left ventricular failure: Most common causes of pericardial effusion o Uremic effusion: 50% of patients with chronic renal failure o Infection  Acute pericarditis: 90% idiopathic or viral  Tuberculosis  Most common cause of constrictive pericarditis in developing world  Tamponade, frequent complication  Blunt/penetrating trauma  Thermal injury  Endocarditis, sepsis o Cardiac surgery: Typical spontaneous resolution  Up to 6% may become clinically significant; cardiac tamponade 422

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o o o o

Autoimmune disease  Rheumatoid arthritis: Effusion in 2-10%  Systemic lupus erythematosus (SLE): Up to 50% with symptomatic effusion  Systemic sclerosis: Up to 70% with small effusion Neoplasia Hypoalbuminemia, myxedema Drug reaction, radiation, trauma Effusive constrictive pericarditis  Constrictive physiology ± associated pericardial effusion or tamponade  Persistent elevated right-chamber pressures after pericardial fluid drainage

Pathophysiology  Pericardial effusion: Rate of fluid accumulation o Gradual increase in pericardial fluid: May accommodate > 1 L without tamponade o Rapid increase in pericardial fluid: Cardiac tamponade, impaired cardiac filling  Cardiac tamponade o ↓ intracardiac volume; ↑ diastolic filling pressures o ↑ intrapericardial pressure with cardiac compression o Rate of fluid accumulation is more significant than fluid volume or composition CLINICAL ISSUES Presentation  Most common signs/symptoms o May be asymptomatic o Chest pain: Worse with inspiration & supine position o Pericardial friction rub in acute pericarditis  Other signs/symptoms o Pericardial tamponade  Anxiety, dyspnea, chest pain, jugular vein distention  Tachycardia, hypotension  Paradoxical pulse: > 10 mm Hg drop in systolic arterial pressure during inspiration  Beck triad  Muffled heart sounds  Hypotension  Jugular vein distention Treatment  Small pericardial effusions may not require treatment  Increased hemodialysis; renal failure-related effusion  Increasing effusion or effusion > 250 mL o Pericardiocentesis (image guided)  93% success rate o Surgical drainage  Preferred for hemopericardium and purulent effusion  Pericardial window, subxiphoid pericardiotomy  Pericardiectomy  Balloon pericardiotomy in recurrent tamponade  Emergent management of tamponade  Anti-inflammatory agents for acute idiopathic/viral pericarditis DIAGNOSTIC CHECKLIST Image Interpretation Pearls  Recognition of normal fluid-filled pericardial recesses, which may mimic lymph nodes and congenital cysts SELECTED REFERENCES 1. O'Leary SM et al: Imaging the pericardium: appearances on ECG-gated 64-detector row cardiac computed tomography. Br J Radiol. 83(987):194-205, 2010 2. Palmer SL et al: CT-guided tube pericardiostomy: a safe and effective technique in the management of postsurgical pericardial effusion. AJR Am J Roentgenol. 193(4):W314-20, 2009 3. Parker MS et al: Radiologic signs in thoracic imaging: case-based review and self-assessment module. AJR Am J Roentgenol. 192(3 Suppl):S34-48, 2009. Review. Erratum in: AJR Am J Roentgenol. 193(3 Suppl):S58, 2009 4. Little WC et al: Pericardial disease. Circulation. 113(12):1622-32, 2006. Review. Erratum in: Circulation. 115(15):e406, 2007 5. Restrepo CS et al: Imaging findings in cardiac tamponade with emphasis on CT. Radiographics. 27(6):1595-610, 2007 423

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Image Gallery

(Left) Axial CECT of a patient with systemic lupus erythematosus (SLE) shows a small to moderately sized pericardial effusion . Up to 50% of patients with SLE may present with symptomatic pericardial effusions. (Right) Axial NECT of a patient with blunt trauma to the chest demonstrates a high-attenuation pericardial effusion consistent with hemopericardium. High-attenuation pericardial effusions may also represent purulent or malignant pericardial effusions.

(Left) Graphic depicts the anatomic basis for the “fat pad” sign. Fluid in the pericardial space will appear as a water-density stripe outlined by the fat-density retrosternal mediastinal fat and the subepicardial fat located beneath the serous visceral pericardium or epicardium. (Right) Lateral chest radiograph demonstrates the “fat pad” sign. A water-attenuation stripe between the mediastinal fat and subepicardial fat represents a pericardial effusion.

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(Left) SSFP cine MR of a patient with a pericardial effusion shows the hyperintense signal surrounding the heart without evidence for septations or nodules, consistent with simple fluid. (Right) SSFP cine MR of the same patient demonstrates the hyperintense pericardial effusion . The parietal serous and fibrous pericardial layers appear as a thin, hypointense structure surrounding the effusion. P.5:40

(Left) Posteroanterior chest radiograph demonstrates a “water bottle” configuration of the cardiac silhouette. The “water bottle” sign of a pericardial effusion appears as globular enlargement of the cardiac silhouette with a normal superior mediastinum. (Right) Lateral chest radiograph of the same patient with a large pericardial effusion shows the “fat pad” sign. The pericardial effusion appears as a water-attenuation stripe between the mediastinal fat and subepicardial fat .

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(Left) Graphic shows the anatomy of the pericardium, which envelops the heart, the distal superior vena cava, the proximal ascending aorta, and the pulmonary trunk, forming pericardial recesses. (Right) Coronal NECT of a patient with recent central line placement demonstrates a hemorrhagic pericardial effusion adjacent to the pulmonary trunk and ascending thoracic aorta , which are intrapericardial structures.

(Left) Axial CECT of a patient who presented with chest pain shows a Stanford type A aortic dissection . A small amount of fluid is present within the mediastinum and adjacent to the aorta . (Right) Axial CECT of the same patient demonstrates extension of the dissection flap into the descending thoracic aorta. A pericardial effusion is present. Note the mass effect exerted on the right ventricle , representing cardiac tamponade. P.5:41

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(Left) Axial CECT of a patient with idiopathic acute pericarditis demonstrates a small pericardial effusion without evidence of septations or enhancement. (Right) Axial CECT of a patient with lymphomatous involvement of the pericardium, lungs, and pleura shows a large pericardial effusion and a small left pleural effusion . Pericardial involvement by lymphoma may manifest as a pericardial effusion, pericardial thickening ± enhancement, or pericardial nodules ± masses.

(Left) Axial CECT of a patient with infectious pericarditis shows a large pericardial effusion and pericardial thickening and enhancement . Note the bilateral pleural effusions, which are larger on the left than on the right. (Right) Sagittal CECT of the same patient demonstrates circumferential pericardial thickening and enhancement , indicating inflammation. These findings may be seen in the setting of infectious, inflammatory, or neoplastic pericarditis.

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(Left) SSFP cine MR of a patient with end-stage renal disease demonstrates a large, hyperintense pericardial effusion . Note that the normal parietal pericardium is straight and smooth, but the visceral pericardium may have a lobular contour where it covers epicardial fat. (Right) SSFP cine MR of the same patient shows a uremic pericardial effusion . Simple pericardial effusions demonstrate homogeneous T1 hypointensity and T2 hyperintensity.

Pericardial Tamponade Pericardial Tamponade Jonathan D. Dodd, MD, MSc, MRCPI, FFR(RCSI) Darragh Brady, MD Key Facts Terminology  Compression of heart chambers by pericardial fluid, gas, or solid tissue with hemodynamic sequelae o Pressure-volume curve of space between visceral and parietal layers depends on rate of accumulation Imaging  Serial chest radiographs: Rapid increase in cardiac silhouette  Echocardiography: Tamponade physiology in setting of > 50 mL fluid o Diastolic collapse of right atrium is earliest sign, followed by persistence in systole  MR: Functional images may demonstrate collapse of right atrium and ventricle and enlarged systemic veins  CT: Pericardial calcification suggests chronic effusion/constriction Top Differential Diagnoses  Serous pericardial effusion  Hemorrhagic pericardial effusion  Fibrinous pericardial effusion  Lymphatic pericardial effusion Clinical Issues  Spectrum of severity, ranging from asymptomatic to complete cardiovascular collapse  Acute tamponade o Tachycardia and pulsus paradoxus (inspiratory drop of > 10 mm Hg in systolic blood pressure) o Treat with pericardiocentesis  Subacute or chronic tamponade o Signs of right heart failure predominate o Hepatomegaly, ascites, peripheral edema

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(Left) Axial CTA shows a type A dissection flap in the ascending aorta, extending into the descending aorta with thrombus within the false lumen and blood within the transverse pericardial recess . (Right) Axial CTA at the level of the ventricles shows extensive pericardial hemorrhagic effusion secondary to aortic rupture. CT fluid density can be useful in fluid differentiation (water density = transudative; above water density = blood/pus/malignancy; below water density = chylous).

(Left) Four-chamber echocardiogram during right ventricular diastole shows a large pericardial effusion and normal configuration of the right atrial wall . Note the circumferential nature of the pericardial effusion, which is typical of tamponade. (Right) Corresponding echocardiogram during ventricular systole shows right atrial free-wall collapse typical of pericardial tamponade in a case of pericardiocentesis-proven malignant pericardial effusion in the setting of breast cancer. P.5:43

TERMINOLOGY Definitions  Compression of heart chambers by pericardial fluid, gas, or solid tissue with hemodynamic sequelae o Potential space separates visceral and parietal serosal layers and normally contains up to 50 mL of serous fluid (plasma ultrafiltrate)  Pressure-volume curve behavior of this finite space depends on rate of accumulation  When intrapericardial pressure rises to critical point, lowest pressure chambers are compressed first, and hemodynamic sequelae are manifest IMAGING General Features  Best diagnostic clue 429

Diagnostic Imaging Cardiovascular o Rapid increase in size of cardiac silhouette on serial chest radiographs Location o Pericardial space between visceral (adjacent to heart = epicardium) and parietal (adjacent to mediastinum) pericardium layers  Earliest collection of pericardial fluid occurs adjacent to posterolateral left ventricular wall or inferolateral right ventricle wall  Subsequently, superior recess is filled  Moderate-sized collections of fluid (100-500 mL) then tend to accumulate adjacent to anterior free wall of right ventricle (> 5 mm)  Large effusions are seen anterior to right atrium and right ventricle, with asymmetric ring of fluid around heart  No direct correlation between thickness of pericardial cavity and actual volume of fluid because fluid does not spread homogeneously Radiographic Findings  Rapid increase in size of cardiac silhouette on serial chest radiographs  “Water bottle” configuration with symmetrically enlarged cardiac silhouette  Loss of retrosternal clear space on lateral chest radiograph  “Fat pad” sign: Separation of retrosternal from epicardial fat line  “Differential density” sign: Increased lucency around heart margin secondary to effusion  Normal lung parenchyma Fluoroscopic Findings  Often right heart catheterization is performed under fluoroscopy o Right atrial pressures are elevated, and systole is followed by large X descent, but diastolic equalization of pressures leads to a diminished Y descent o If intraatrial pressures fail to decrease as fluid is drained, effusive-constrictive pericarditis should be considered CT Findings  Dilated inferior vena cava and superior vena cava  Deformed ventricular contour with flattening of contours  Straightening of interventricular septum  Effusion density > 35 HU is suggestive of hemorrhagic effusion  Mediastinal lymphadenopathy is suggestive of tuberculous or neoplastic etiology  Congestive hepatomegaly with periportal edema  Pericardial calcification suggests chronic effusion/constriction MR Findings  Cine MR may demonstrate collapse of right atrium and ventricle and enlarged systemic veins  Simple, transudative effusions have low signal on T1-weighted images and high signal on T2-weighted FSE and SSFP images  Complex effusions, such as exudative and hemorrhagic fluid, have high signal on T1-weighted and intermediate signal on T2-weighted spin-echo images  On SSFP cine sequences, fibrin strands or blood, associated with loculations, can be seen  With use of double-inversion recovery in FSE sequences, signal depends on presence of flow within collection o Free-flowing collections, such as transudates, have no signal o Complex collections without flow have intermediate to high signal  Septations or contrast enhancement may suggest infection  May demonstrate pericardial masses, indicating neoplastic etiology  Septal bounce may be identified on real-time MR echo o Septum may oscillate into left ventricle during exaggerated respiratory variation Echocardiographic Findings  Hypoanechoic band between pericardial layers  Size of effusion does not indicate its hemodynamic significance  In large effusions, heart may swing within pericardial fluid on beat-to-beat basis and correlates with electrical alternans  Diastolic collapse of right atrium is earliest sign, followed by persistence in systole  Right ventricular collapse is less sensitive but more specific  > 35% respiratory difference in transmitral inflow velocities and tricuspid inflow of > 80% correlated best with tamponade physiology in comparison hemodynamic studies  Plethoric inferior vena cava with no respirophasic change; most sensitive, not specific 

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Diagnostic Imaging Cardiovascular  Presence of loculations may suggest infection Imaging Recommendations  Best imaging tool o Echocardiography showing tamponade physiology in setting of > 50 mL fluid DIFFERENTIAL DIAGNOSIS Serous Pericardial Effusion  Congestive heart failure  Any cause of hypoalbuminemia P.5:44

Hemorrhagic Pericardial Effusion  Iatrogenic (most common cause)  Ruptured aortic dissection  Trauma  Acute myocardial infarction  Neoplasm o Metastases (lung, breast, melanoma, leukemia, lymphoma) o Mesothelioma o Angiosarcoma o Teratoma Fibrinous Pericardial Effusion  Infection o Viral o Pyogenic o Tuberculosis  Uremia  Connective tissue disease o Rheumatoid arthritis o Systemic lupus erythematosus o Acute rheumatic fever Lymphatic Pericardial Effusion  Neoplasm  Congenital  Iatrogenic PATHOLOGY General Features  Etiology o Viral pericarditis  Most commonly adeno- or coxsackievirus o Hemorrhage  Dissecting aortic aneurysm rupture into pericardial space  Traumatic or iatrogenic o Acute myocardial infarction o Renal failure o Neoplasm CLINICAL ISSUES Presentation  Most common signs/symptoms o Spectrum of severity, ranging from asymptomatic to complete cardiovascular collapse o In acute tamponade, features include  Tachycardia (earliest feature, almost always present)  Elevated venous pressure with Kussmaul sign  Distant heart sounds  Dyspnea and tachypnea  Chest pain (if pericarditis or myocardial infarction)  Pulsus paradoxus  Inspiratory drop of > 10 mm Hg in systolic blood pressure 431

Diagnostic Imaging Cardiovascular  Diastolic filling is reduced as intrapericardial pressure rises  Reduced preload may lead to shock o In subacute or chronic tamponade, signs of right heart failure predominate  Hepatomegaly, ascites, peripheral edema  Other signs/symptoms o ECG shows  Reduced voltage  ST elevation and PR depression in setting of pericarditis Treatment  Interventional o Pericardiocentesis for acute tamponade  Beware, hemopericardium may be due to aortic dissection, and pericardiocentesis may be catastrophic o Echocardiography guidance reduces major complications from 20% to < 1.5% o Use extrapleural subxiphoid approach o Drainage should continue until aspirated volume is < 25 mL/day  Surgical o Recurrent effusions may be treated by repeat pericardiocentesis, surgical creation of pericardial window, or pericardiectomy (when expected survival is > 1 year) o Video-assisted thoracoscopic pericardiectomy is alternative to open thoracotomy SELECTED REFERENCES 1. Azam S et al: Treatment of pericardial disease. Cardiovasc Ther. 29(5):308-14, 2011 2. Dawson D et al: Contemporary imaging of the pericardium. JACC Cardiovasc Imaging. 4(6):680-4, 2011. Erratum in: JACC Cardiovasc Imaging. 4(7):819, 2011 3. Rajiah P: Cardiac MRI: Part 2, pericardial diseases. AJR Am J Roentgenol. 197(4):W621-34, 2011 4. Fortuño Andrés JR et al: Radiological approach to cardiac tamponade. Radiologia. 52(5):414-24, 2010 5. Rajiah P et al: Computed tomography of the pericardium and pericardial disease. J Cardiovasc Comput Tomogr. 4(1):3-18, 2010 6. Yared K et al: Multimodality imaging of pericardial diseases. JACC Cardiovasc Imaging. 3(6):650-60, 2010 7. Hussain SM et al: Superior vena cava perforation and cardiac tamponade after filter placement in the superior vena cava—a case report. Vasc Endovascular Surg. 39(4):367-70, 2005 8. Klein SV et al: CT directed diagnostic and therapeutic pericardiocentesis: 8-year experience at a single institution. Emerg Radiol. 11(6):353-63, 2005 9. Weich HS et al: Large pericardial effusions due to systemic lupus erythematosus: a report of eight cases. Lupus. 14(6):450-7, 2005 10. Chang K et al: Infective endocarditis of the aortic valve complicated by massive pericardial effusion and rupture of a sinus of valsalva into the right atrium. J Am Soc Echocardiogr. 17(8):910-2, 2004 11. Collins D: Aetiology and management of acute cardiac tamponade. Crit Care Resusc. 6(1):54-8, 2004 12. Kabukcu M et al: Pericardial tamponade and large pericardial effusions: causal factors and efficacy of percutaneous catheter drainage in 50 patients. Tex Heart Inst J. 31(4):398-403, 2004 13. Spodick DH: Acute cardiac tamponade. N Engl J Med. 349(7):684-90, 2003 14. Kuvin JT et al: Postoperative cardiac tamponade in the modern surgical era. Ann Thorac Surg. 74(4):1148-53, 2002 15. Goldstein L et al: CT diagnosis of acute pericardial tamponade after blunt chest trauma. AJR Am J Roentgenol. 152(4):739-41, 1989 P.5:45

Image Gallery

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(Left) Four-chamber view GRE MR in a patient with melanoma shows a lobulated mass arising from the right ventricular free wall, consistent with a metastasis. Note the moderate pericardial effusion , which nevertheless caused pericardial tamponade. (Right) Four-chamber view GRE MR in the same patient at a more caudal level shows the dominant right ventricular free-wall metastasis and additional pericardial nodules , consistent with pericardial metastases and neoplastic effusion.

(Left) Chest radiograph in a 23-year-old man shows a globular, football-shaped, enlarged cardiac silhouette . Findings are typical of a pericardial effusion. (Right) Corresponding axial CTA image several days later shows a large pericardial effusion and enhancing pericardium , features consistent with acute pericarditis. Also note the large bilateral pleural effusions . The patient required a pericardial drain due to tamponade physiology.

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(Left) Axial GRE MR shows a large invasive mass arising from the right ventricular free wall. Note the associated moderate malignant pericardial effusion , always an ominous finding in the presence of a cardiac mass. (Right) Corresponding axial PET/CT demonstrates avid FDG uptake within the right ventricular mass, consistent with a malignant tumor. The lack of evidence of FDG uptake elsewhere indicates a primary cardiac tumor. Biopsy revealed cardiac lymphoma.

Section 6 - Neoplastic Approach to Neoplastic Disease Approach to Neoplastic Disease Kathryn M. Olsen, MD John D. Grizzard, MD Introduction Evaluation of a known or suspected cardiac neoplasm has become an increasingly common source of referrals for further cross-sectional imaging, particularly using cardiac MR. Most often, masses are found as incidental findings in patients evaluated with echocardiography or computed tomography for other indications. This chapter discusses the imaging modalities available for the evaluation of cardiac masses and their respective advantages and disadvantages. It also briefly considers the anatomic and imaging characteristics of various types of masses, most of which are covered in detail in dedicated chapters. Finally, the chapter proposes a systematic imaging approach to the evaluation of known or suspected cardiac neoplasms that aims to narrow the set of differential diagnostic considerations with a high degree of confidence. Imaging Considerations In the evaluation of cardiac masses, specific information can be gleaned from imaging, which is helpful in narrowing the differential diagnosis. To make the proper diagnosis, one should:  Localize the lesion to an intracavitary, intramural, or epicardial/pericardial location, which will greatly narrow the differential diagnosis  Determine the composition of the lesion (i.e., cystic vs. solid; heterogeneous vs. homogeneous; fat vs. calcium containing)  Evaluate the lesion margins as well defined vs. infiltrating  Determine the tumor vascularity with perfusion imaging  Use the enhancement pattern on late gadolinium enhancement (LGE) While echocardiography is widely available and readily performed, it has significant limitations in characterizing solid masses owing to its poor soft tissue contrast. Also, in many patients, lack of acoustic windows limits visualization of cardiac structures. Cardiac CT has unrestricted imaging windows, and its soft tissue contrast resolution is superior to that of echocardiography but inferior to that of MR. Its temporal resolution is inferior to that of echocardiography or MR, and it requires ionizing radiation. CT is superior to MR and echo for identification of calcification. However, for small, highly mobile lesions, echocardiography may be test of choice due to high temporal resolution. MR can provide information regarding lesion perfusion as well as LGE data from a single administration of contrast. MR cine imaging can simultaneously visualize the lesion borders and evaluate its impact on cardiac function. The most 434

Diagnostic Imaging Cardiovascular significant advantage of MR is that of improved soft tissue contrast. The pattern of delayed enhancement demonstrated by a given lesion can also frequently provide important information leading to the correct diagnosis. For example, thrombus (which is the most common cardiac mass) has LGE properties that allow conclusive differentiation from normal myocardium as well as most neoplasms. Because of its unrestricted field of view and its ability to characterize tissue and evaluate cardiac function, anatomy, and perfusion, MR is the imaging modality of choice in the workup-up of suspected cardiac neoplasms. CT protocols are dependent on the chamber of interest and may include noncontrast and delayed acquisition as well as retrospectively gated or prospectively triggered CTA acquisitions. Multiphasic data sets can be acquired to determine the behavior of the mass throughout the cardiac cycle. Suggested MR Protocol The protocol suggested for imaging cardiac masses can be thought of as attempting to answer specific questions. Specifically, for lesion detection and morphologic delineation, imaging can be performed with both bright blood (SSFP) and dark blood (HASTE or FSE) single-shot techniques throughout the entire chest. Cardiac structure and function are evaluated using SSFP cine images in the standard short-axis and long-axis imaging planes. On occasion, dedicated T1and T2-weighted fast spin-echo imaging may be helpful in lesion characterization. Fat-suppression techniques can be used when appropriate. Gadolinium-based contrast often proves very helpful in further tissue characterization and can be administered as part of a perfusion sequence to assess lesion vascularity. Delayed-enhancement imaging using the standard segmented T1-weighted inversion-recovery gradient-echo sequence with an inversion time set to null normal myocardium will often allow differentiation of cardiac masses and their borders from adjacent normal myocardium. Images with a long inversion time often prove helpful in the assessment of suspected cardiac thrombus. Single-shot versions of these inversion recovery imaging sequences can be obtained even in arrhythmic or uncooperative patients with only a minimal decrease in sensitivity. Lastly, a breath-held fat-suppressed volumetric 3D acquisition (acronyms: VIBE, LAVA, THRIVE, TIGRE) of the entire chest may be obtained in < 20 seconds and can provide global evaluation of the heart, mediastinum, and lung structures as well as of the chest wall. Intracavitary Lesions Myxomas make up approximately 50% of all primary benign cardiac neoplasms. Myxomas are located in the left atrium in approximately 75-80% of cases and are usually attached to the fossa ovalis. Noncontrast SSFP cine images often demonstrate higher signal intensity than myocardium, owing to the high T2 signal of the myxoid matrix present. This fact is helpful in differentiating these lesions from thrombi, which are isointense to myocardium pre contrast. Myxomas (particularly the stalk) usually demonstrate heterogeneous enhancement on delayed-enhancement images with a short inversion time. On long inversion time images, the gelatinous component of the lesion may be quite dark, mimicking the appearance of a thrombus. Thrombus is the most common cardiac “mass” although it is not a neoplasm. Thrombi are often seen in the left atrium in patients with atrial fibrillation and in the ventricles adherent to areas of infarction. Although they may have low signal on long inversion time LGE imaging like some myxomas, thrombi are isointense to myocardium on noncontrast SSFP cine imaging. Metastases can extend into the cardiac chambers via the inferior vena cava from renal or hepatic carcinomas or via the pulmonary veins from lung carcinomas. Of the P.6:3 intracavitary entities, usually only metastatic lesions show intense enhancement on LGE imaging. Valvular Lesions Papillary fibroelastoma in some series are said to be the second most common cardiac tumor. They are small (≤ 1 cm) excrescences found on valve surfaces (90%) and are most often discovered incidentally on an echocardiogram performed for another indication but have been reported to cause neurological symptoms, presumably on an embolic basis. Vegetations are best thought of as infected thrombi attached to valves and are often associated with valve dysfunction and distal embolization. Their signal characteristics mimic those of thrombi. Intramural Lesions, Malignant Metastatic disease is reported to be roughly 40 times more common than primary cardiac neoplasia. Cardiac metastases almost always occur in the setting of advanced, known malignancy. Typical metastatic lesions demonstrate infiltration of normal structures with poorly defined margins. Pericardial effusions are frequently associated. Heterogeneous enhancement on LGE is common. Primary cardiac sarcomas are rare, and they have many imaging features in common with metastatic disease. Angiosarcomas make up roughly 50% of sarcomas and are usually right atrial in origin; the other sarcomas have a left atrial predominance. Primary cardiac lymphoma is a rare B-cell tumor with an infiltrating, aggressive appearance occurring most often in immunocompromised patients. It tends to involve the right ventricle. Intramural Lesions, Benign 435

Diagnostic Imaging Cardiovascular Lipomatous hypertrophy of the interatrial septum is not a neoplasm but refers to infiltration of the interatrial septum by unencapsulated adipocytes. It spares the fossa ovalis, resulting in the classic “dumbbell” appearance. Lipomas are rare, benign tumors that are true neoplasms that may arise along the epicardium or in an intramural location. They show characteristic fat suppression on MR. Paragangliomas are typically well-encapsulated lesions seen in patients with symptoms of catecholamine excess. They are very vascular lesions and tend to occur in the atria, along the atrioventricular sulcus, and at the roots of the great vessels. They are light-bulb bright on T2 images. Intramural Lesions in Children Rhabdomyoma is the most common cardiac neoplasm in children and is most often seen in children with tuberous sclerosis. The lesions are often multiple and typically involve the ventricular free walls and interventricular septum. Their signal intensity is similar to normal myocardium on cine and LGE imaging, meaning that they null (or go dark) similar to normal myocardium. Fibroma is the second most common childhood neoplasm. It is a solitary mass of fibroblasts and collagen that typically involves the ventricular free walls and interventricular septum. In older children and adults, fibromas may be dark on T2 imaging, a characteristic finding. On LGE imaging, they show intense enhancement (bright signal), differentiating them from rhabdomyomas. Epicardial/Pericardial Lesions Metastatic lesions involve the pericardium more frequently than the myocardium. They often result in nodular regions of pericardial thickening and are usually associated with pericardial effusions or hemopericardium. Pericardial cysts, although not neoplasms, may sometimes cause mass effects requiring differentiation from more serious lesions. Their signal characteristics are those of simple fluid. Hemangiomas and lymphangiomas are both tumors of endothelial cells and contain either blood (hemangiomas) or lymph (lymphangiomas). Both are bright on T2 images, but only hemangiomas demonstrate increased vascularity on perfusion imaging. Tumor Mimics/Pseudomasses Occasionally, cardiac and paracardiac structures may have a confusing echocardiographic appearance and simulate a mass. For instance, a hiatal hernia may be partially visualized as a cystic structure posterior to the left atrium on echocardiography. More commonly, normal cardiac structures, such as the crista terminalis, may mimic a true cardiac lesion. A prominent Chiari network can also be mistaken for a right atrial mass, and so can a prominent eustachian valve. All of these normal structures can be well visualized on MR, and a true mass can thus be excluded. Differential Diagnosis The diagnostic path starts with localizing the epicenter of the lesion as being intracavitary, intramural, or epicardial. Defining the lesion as sharply marginated or infiltrating is helpful in the analysis of intramural and epicardial lesions. Perfusion and LGE sequences will indicate the vascularity of the lesion and help to narrow the differential diagnosis. For example, an intracavitary mass with well-defined borders arising in the left atrium attached to the fossa ovalis will likely be a myxoma. On the other hand, a bulky infiltrating lesion arising in the wall of the left atrium and demonstrating vigorous enhancement will likely be a primary sarcoma (or a metastatic lesion), even if it protrudes into the left ventricular cavity. Selected References 1. Beroukhim RS et al: Characterization of cardiac tumors in children by cardiovascular magnetic resonance imaging: a multicenter experience. J Am Coll Cardiol. 58(10):1044-54, 2011 2. O'Donnell DH et al: Cardiac tumors: optimal cardiac MR sequences and spectrum of imaging appearances. AJR Am J Roentgenol. 193(2):377-87, 2009 3. Grizzard JD et al: Magnetic resonance imaging of pericardial disease and cardiac masses. Magn Reson Imaging Clin N Am. 15(4):579-607, vi, 2007 4. Araoz PA et al: CT and MR imaging of benign primary cardiac neoplasms with echocardiographic correlation. Radiographics. 20(5):1303-19, 2000 5. Araoz PA et al: CT and MR imaging of primary cardiac malignancies. Radiographics. 19(6):1421-34, 1999 P.6:4

Tables Comparison of Imaging Modalities for Evaluating Cardiac Neoplasms

Echocardiography Advantages Availability, portability, and relatively rapid image acquisition; good spatial

Cardiac CT

Cardiac MR

Unlimited imaging windows; can provide multiplanar reconstructions; less operator

Unlimited, multiplanar imaging; superior soft tissue contrast; simultaneous assessment of

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resolution and excellent temporal resolution

dependent; fair soft tissue function; perfusion imaging contrast; best for delineation of without radiation calcium

Disadvantages Need for adequate acoustic windows; limited soft tissue contrast resolution when compared with CT or MR

Relatively poor temporal resolution; potentially nephrotoxic contrast is usually required; ionizing radiation is required

Not universally available; pacemakers and older aneurysm clips are contraindicated; gadolinium contrast is contraindicated in patients with renal insufficiency

Suggested MR Imaging Protocol

Sequences Single-shot SSFP and HASTE/FSE Cine SSFP

Imaging Planes Axial/sagittal/coronal stack Short- and long-axis stack Short and long axis

T1 and T2 FSE/fat suppression Perfusion imaging

Short- and long-axis stack

Coverage Entire thorax Heart base to apex Tailored to lesion Tailored to lesion Heart base to apex

Short- and long-axis stack

Heart base Thrombus detection to apex

Short and long axis

LGE images with time inversion to null myocardium LGE images with long time inversion (˜ 600 milliseconds)

Imaging Information Obtained Overview of cardiac/mediastinal structures; lesion localization Lesion visualization; cardiac function Lesion tissue characterization Lesion vascularity Enhancement characteristics

Cardiac Masses by Location

Location

Lesion

Intracavitary

Thrombus

Myxoma

Metastasis

Valvular

Papillary fibroelastoma Vegetations

Intramural, malignant

Metastasis

Primary sarcoma

Lymphoma

Typical Imaging Features Differentiating MR Features Any chamber; varies from Isointense to myocardium round to mural on SSFP cine imaging; nulls at inversion time ˜ 600 milliseconds 85% left atrial attached to Hyperintense to fossa ovalis, 10-12% right myocardium on SSFP cine or biatrial imaging; stalk enhances Solitary or multiple; mass Transvenous extension of effect tumor; heterogeneous enhancement Small-stalked mass arising Usually low signal on cine along a valve or and T1 images endocardium Perivalvular or attached to May have concomitant thickened, abnormal valve embolic disease Multiple infiltrative lesions Heterogeneously enhances in patients with known on perfusion and LGE malignancy imaging Solitary bulky, infiltrative Heterogeneously enhances mass; right atrial on perfusion and LGE angiosarcoma most imaging common (50%) Typically large, infiltrative Variable enhancement, 437

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mass; right ventricular often less than metastases involvement common Fatty signal in interatrial Fat suppression septum with barbell shape

Lipomatous hamartoma of interatrial septum Lipoma Intramural or epicardial; Fat suppression rarely protrudes into cavity Paraganglioma Well-defined lesion in Light-bulb bright on T2patient with catecholamine weighted images excess Rhabdomyoma Commonly multiple; Isointense to myocardium Intramural, in involve ventricular free on SSFP cine and LGE children walls and septum; imaging; nulls like normal associated with tuberous myocardium sclerosis Fibroma Solitary lesion; involves Bright on LGE imaging ventricular free walls and (may have a dark core) septum; associated with Gorlin syndrome Pericardial metastasis is Effusions are very Epicardial/pericardial Metastasis more common than common and may result in myocardial lesion symptoms Cyst Well-defined nonenhancing Signal follows fluid on all lesion contiguous with sequences pericardium Hemangioma Multicystic enhancing High signal on T1 and T2 lesion; may involve images; usually epicardium and hypervascular on perfusion pericardium; may also be imaging intramural or intracavitary Lymphangioma Rare multicystic lesion; Low in signal on T1may be intramural, weighted images, high on epicardial, or pericardial T2; hypovascular on perfusion imaging Intramural, benign

P.6:5

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(Left) Coronal oblique MR cine image of a patient with renal cell carcinoma shows tumor extending through the inferior vena cava into the right atrium. There is also tumor embolism to the right pulmonary artery . (Right) Four-chamber view MR cine (top) and LGE obtained with an inversion time of 600 milliseconds (bottom) show an apical thrombus . Note that the thrombus is isointense to myocardium on the cine image, which is different from the appearance of myxomas.

(Left) Vertical long-axis (2-chamber) MR cine (left) and LGE (right) images in a patient with atrial fibrillation show a left atrial thrombus . Note that the thrombus is isointense to myocardium on SSFP cine imaging. (Right) Vertical longaxis (2-chamber) MR SSFP cine images in systole (left) and diastole (right) show a large myxoma . Note that the lesion almost completely obstructs the mitral valve inflow in diastole . Note also that the lesion is higher in signal than the myocardium.

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(Left) Short-axis MR cine (left) and LGE (right) images show a large right atrial myxoma that is attached to the inferior wall via a short stalk . The LGE image, obtained with a 600 milliseconds inversion time, shows enhancement of the stalk, but most of the lesion is dark, similar to thrombus. However, the myxoma is brighter in signal than the myocardium on the SSFP cine image, indicating the gelatinous nature of the lesion. (Right) Four-chamber view MR cine image shows a biatrial myxoma . P.6:6

(Left) Four-chamber view MR cine images in diastole (top) and systole (bottom) show large vegetations of the tricuspid valve that are associated with significant valvular dysfunction . (Right) Four-chamber view MR cine (top) and LGE (bottom) images show a metastasis from colon carcinoma producing an intracavitary lesion of the right ventricular apex . Note the high signal of the lesion on LGE imaging. Of the intracavitary lesions, metastases tend to show the greatest enhancement.

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(Left) Four-chamber view T1 (top) and T2 (bottom) WI FSE MR images show a well-defined intramural mass originating in the interatrial septum. The lesion is isointense on T1 and light-bulb bright on T2 , findings characteristic of a paraganglioma. (Right) Short-axis MR cine (left) and T1 FSE (right) images show rhabdomyomas of the anterior and inferior left ventricular walls . The lesions have signal intensity similar to that of normal myocardium on all sequences.

(Left) Short-axis MR cine (top left) and LGE (top right) and 3-chamber cine (bottom left) and LGE (bottom right) images of a fibroma of the right ventricular outflow tract (RVOT) show that the lesion is sharply demarcated from normal myocardium and shows intense enhancement . (Right) Four-chamber view MR cine image of an angiosarcoma shows the characteristic right atrial location. Note the infiltration of the right atrial wall by this aggressive lesion and the pedunculated intracavitary components . P.6:7

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(Left) Four-chamber view MR cine (left) and 2-chamber view MR cine (right) images of a bulky, infiltrating left atrial mass due to an osteosarcoma illustrate the importance of lesion margins and MR appearance in differentiating benign and malignant lesions. Note that the nearly total obstruction of the mitral valve is clearly seen on MR imaging, as is the turbulent flow produced . (Right) Four-chamber (top) and short-axis (bottom) MR cine images of primary cardiac lymphoma show right ventricular involvement .

(Left) RVOT T1WI FSE MR image demonstrates high signal intensity lesions infiltrating the RVOT in a patient with metastatic melanoma. The high signal on precontrast T1 (likely due to melanin) is highly suggestive of this diagnosis. (Right) Horizontal long-axis (4-chamber) MR cine image shows 2 infiltrating lesions of the myocardium in a patient with lung carcinoma. Metastatic lesions are often multiple and show poor definition of margins, as seen in this case.

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(Left) Vertical long-axis (2-chamber) MR cine , perfusion early and late arterial phase, and LGE images of hypervascular renal cell carcinoma metastases in the anterior and inferior left ventricular walls show that the lesions enhance on the perfusion and LGE images. (Right) Short-axis MR cine images of a prominent eustachian valve (left) and of a large hiatal hernia (right) illustrate the fact that various structures can mimic a cardiac mass.

Metastatic Disease Metastatic Disease John P. Lichtenberger, III, MD Key Facts Terminology  Metastatic tumor deposition or extension of primary tumor into heart  Metastases to heart occur via o Lymphatic spread o Direct extension o Hematogenous spread o Transvenous spread Imaging  Initial manifestation may be lung, bone, or mediastinal metastases  Pericardial effusion is common  Mediastinal lymphadenopathy in 80% of cases of cardiac metastatic disease  Pleural effusion in 50%  Ascites  Most metastases enhance with gadolinium Top Differential Diagnoses  Thrombus  Primary cardiac neoplasm o Myxoma: Benign, most common o Malignant primary cardiac tumors are rare  Myopericarditis Pathology  Immunohistochemical markers may be needed to distinguish from primary cardiac osteosarcoma Clinical Issues  Very poor prognosis Diagnostic Checklist  Malignant pericardial effusion is often 1st sign of cardiac or pericardial metastatic disease  Assess for signs of cardiac tamponade and coronary artery involvement

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(Left) Axial CECT of a patient with metastatic melanoma shows a large, enhancing soft tissue mass of the right atrium extending into the chamber. Note associated pericardial effusion. Multiple subcutaneous metastases and enhancing pulmonary nodular metastases are present . (Right) Axial CECT of a patient with lung cancer shows a left lower lobe mass , which invades the pericardium, and a low-attenuation metastasis arising from the interventricular septum .

(Left) Axial CECT of a patient with mediastinal sarcoma shows a large mediastinal mass extending through the pericardium and subepicardial fat and invading the right ventricular outflow tract . Nodular, enhancing pericardium and pericardial effusion indicate neoplastic pericarditis. (Right) Four-chamber balanced SSFP MR of a patient with lung cancer metastatic to the right ventricle shows an irregular mass centered within the free wall of the right ventricle with a pericardial effusion. P.6:9

TERMINOLOGY Definitions  Metastatic tumor deposition or extension of primary tumor into heart  Metastases to heart occur via o Lymphatic spread: Most common route; lung and breast cancer o Hematogenous spread: Typically melanoma o Direct extension: Usually lung cancer and thoracic malignancies; rarely mesothelioma o Transvenous spread  Inferior vena cava (IVC) from renal cell carcinoma, hepatocellular carcinoma, and adrenal or uterine malignancies 444

Diagnostic Imaging Cardiovascular  Pulmonary vein from lung cancer IMAGING General Features  Best diagnostic clue o Cardiac mass: Metastatic disease is 40x more common than primary cardiac tumor o Often associated with malignant pericardial effusion o Presence of multiple masses favors metastatic disease  Location o Right atrium (RA) and right ventricle (RV) are much more commonly affected than left atrium (LA) and left ventricle (LV) o Epicardium is most commonly affected layer  Morphology o Often infiltrative or growing into cardiac chamber Radiographic Findings  Radiography o Frequently normal o Initial manifestation may be lung, bone, or mediastinal metastases o May mimic valvular heart disease o Cardiac silhouette enlargement (may be irregular) indicating pericardial effusion or cardiomegaly  Pericardial effusion may be diffuse or loculated  Cardiomegaly may be from mass(es) or chamber enlargement secondary to obstruction o Mediastinal lymphadenopathy in 80% of cases of cardiac metastatic disease o Secondary findings  Pulmonary edema  Pleural effusion (50%), ascites o Rarely calcification (osteosarcoma metastasis) CT Findings  NECT o Massive cardiac involvement may lead to chamber enlargement o Calcifications are rare except in certain tumors  Osteosarcoma, chondrosarcoma  Tumors with psammomatous calcification o Fat in liposarcoma metastases o Associated signs of malignancy  Lung and bone metastases  Lymphadenopathy  Pericardial and pleural effusions  CTA o May better demonstrate solid and cystic components o Invasion of myocardium, pericardium, and mediastinal structures o Diffuse involvement or focal metastasis o Metastases may enhance differently relative to myocardium o Best to visualize direct invasion of lung cancer via pulmonary veins o Extension of renal or adrenal mass into RA via IVC  Inhomogeneous mixing of contrast-opacified and nonopacified blood in IVC may mimic tumor thrombus  Delayed imaging is essential o Retrospective cardiac gating may demonstrate valvular impairment from metastases MR Findings  T1WI o Metastases usually have low signal intensity o Melanoma and hemorrhagic metastases may be hyperintense on T1WI  T2WI o High signal intensity relative to myocardium  T1WI C+ o Most metastases enhance with gadolinium  1st pass and delayed enhancement are required  More sensitive than CT for lower grade enhancement o Differentiation from thrombus (chronic thrombus may appear to enhance peripherally) 445

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Best technique is delayed enhancement with very long inversion time (TI = 600 milliseconds)  Tissue characterization with fat-saturated images, T2WI, and T1WI pre- and post-contrast administration o Allows to differentiate lipoma from other neoplasms o Some primary cardiac tumors (e.g., myxoma, fibroma, pericardial cysts) have typical MR properties, but these are often not reliable for differentiating benign from malignant  Better assessment of extent of disease than with CT o Superior contrast resolution allows better detection of metastatic foci  High signal intensity filling defects on T1W black blood images when tumor invades chamber o Slow flow may artificially cause high-signal pseudo filling defects  May detect and quantify hemodynamic consequences of mass o Obstruction of RA inflow, pulmonary veins, RV or LV outflow tracts, or atrioventricular valves o Valvular regurgitation due to tumor infiltration Echocardiographic Findings  Echocardiogram o Procedure of choice for initial evaluation of suspected pericardial effusion  Pericardial effusion in 50% of cases o No positive findings in 25% o Mass or myocardial thickening evident in 40% o May demonstrate associated thrombus o Limited exam  May not show entire pericardium Nuclear Medicine Findings  PET/CT P.6:10

o Limited role, although metastatic foci may show increased FDG uptake relative to myocardium Imaging Recommendations  Best imaging tool o Echocardiography: Usually 1st imaging modality in suspected pericardial effusion o Cardiac MR: Allows better assessment of extent of disease, low level enhancement, and cardiac functional impairment than CT  Superior contrast resolution increases sensitivity for metastatic foci o CT: Best modality for evaluating for osteosarcoma metastasis  Protocol advice o 2-minute delayed scan or MR can confirm presence of IVC tumor when discerning contrast mixing in IVC from venous extension of tumor o When evaluating for enhancement on MR, use imaging parameters before and after gadolinium administration  Allows for comparable pre- and post-contrast images o Choose conventional cardiac imaging plane that best shows mass, then image 3 orthogonal planes o Retrospective cardiac gating in CTA may show valvular impairment from metastases DIFFERENTIAL DIAGNOSIS Thrombus  Most commonly in atria and adjacent to aneurysms  No myocardial invasion, no true enhancement Atrial Myxoma  Most common benign primary tumor  Typically left atrium, stalk-like attachment near foramen ovale  Hypointense on T1 Other Primary Benign Tumors  Rhabdomyoma, hemangioma, etc. Primary Malignant Tumors  Very rare  May mimic metastases with multifocal involvement or pericardial invasion  Primary malignant cardiac tumors o Lymphoma, sarcomas, pericardial mesothelioma, etc. 446

Diagnostic Imaging Cardiovascular o Difficult to differentiate primary cardiac osteosarcoma from metastatic osteosarcoma Myopericarditis  Infectious, inflammatory, drug or radiation induced  May cause enhancing, nodular pericardium, and epicardial enhancement on MR, mimicking metastases PATHOLOGY General Features  Etiology o Most common neoplasms metastatic to heart and pericardium: Lung, breast, melanoma, lymphoma o Bronchogenic carcinoma: Primary tumor in 36% of patients with cardiac metastases o Leukemia & lymphoma: Primary malignancy in 20% o Malignant melanoma and lymphoma: Have highest propensity to metastasize to heart  Associated abnormalities o Malignant pericardial effusions are overwhelmingly secondary to metastases o Extracardiac metastases are typically present  Epicardium is most often involved with metastases Gross Pathologic & Surgical Features  Multiple infiltrating masses in epicardium, myocardium, and endocardium  Over 90% are epithelial in origin (e.g., lung, breast)  Frequently associated sanguineous pericardial effusion Microscopic Features  Immune markers can help discriminate among different cell types  Psammoma bodies in lung and ovarian cancers  Osteosarcoma metastases are unique in that they contain bone elements o Calcium may not be readily visible on MR (signal voids) o Immunohistochemical markers may be needed to distinguish from primary cardiac osteosarcoma CLINICAL ISSUES Presentation  Most common signs/symptoms o Asymptomatic in 50% of cases  Other signs/symptoms o Obstructive symptoms depending on area of flow obstruction o Tamponade from hemorrhagic effusion or compressing tumor mass o Signs of heart failure o Arrhythmias are common Demographics  Epidemiology o 20-40x more frequent than primary cardiac neoplasms Natural History & Prognosis  Very poor prognosis Treatment  Palliative surgery, chemotherapy, or radiation  Treatment of cardiac tamponade from malignant pericardial effusion DIAGNOSTIC CHECKLIST Image Interpretation Pearls  Malignant pericardial effusion is often 1st sign of cardiac or pericardial metastatic disease  Assess for signs of cardiac tamponade and coronary artery involvement  Chronic thrombus may appear to enhance peripherally, mimicking cardiac mass SELECTED REFERENCES 1. Prakash P et al: Imaging findings of pericardial metastasis on chest computed tomography. J Comput Assist Tomogr. 34(4):554-8, 2010 P.6:11

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(Left) Axial cardiac gated CT of a patient with metastatic sarcoma shows a centrally necrotic enhancing mass of the inferolateral left ventricular wall with a large pericardial effusion. (Right) Axial T1WI C+ FS MR of the same patient with metastatic sarcoma shows a peripheral enhancement in the mass as well as diffuse pericardial enhancement indicating a malignant pericardial effusion. Pericardial effusion is often associated with malignant involvement of the heart.

(Left) Axial ECG-gated CTA of a patient with metastatic pancreatic cancer shows low-attenuation masses in the right atrial appendage. Multiple cardiac masses favor metastatic disease. Lymphadenopathy and pericardial effusion are also present . (Right) Short-axis myocardial delayed enhancement MR of a patient with metastatic lung cancer to the heart shows an irregular, infiltrative mass of the right ventricular outflow tract. Metastatic disease more commonly involves the right heart.

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(Left) Axial ECG-gated CTA of a patient with retroperitoneal leiomyoma shows a large, lobulated mass extending through the inferior vena cava into the right atrium and across the tricuspid valve. Masses extending into the heart often only become symptomatic once obstruction occurs. (Right) Axial CECT of a patient with hepatocellular carcinoma shows multiple hepatic masses with extension through the IVC to the RA. Transvenous extension to the heart significantly alters clinical management.

Tumor Extension Into the Atria Tumor Extension Into the Atria John P. Lichtenberger, III, MD Key Facts Terminology  Extracardiac tumor invading atria, typically through growth along venous structures Imaging  Radiography o Findings mimic congestive heart failure o Enlargement of cardiac silhouette: Chamber dilation or pericardial effusion  CT: Retrospectively gated cardiac CTA may show valvular involvement or prolapse into ventricle  Cardiac MR: Best tool to differentiate bland thrombus from tumor thrombus  Balanced cine SSFP: May show valvular involvement or prolapse into ventricle during cardiac cycle  Imaging or reformatting in several planes is important in avoiding artifact and in surgical planning Top Differential Diagnoses  Thrombus  Pseudothrombosis  Myxoma  Other primary cardiac tumors Clinical Issues  Heart failure, edema, dyspnea  Syncope, arrhythmia Diagnostic Checklist  Evaluate for associated bland thrombus as intraatrial tumors disrupt flow dynamics  Tumor extension into atria will often alter surgical planning and complicate radiation therapy  Valvular involvement is important for operative planning

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(Left) Axial cardiac gated CTA of a patient with pelvic leiomyosarcoma shows a lobulated mass extending through the inferior vena cava (IVC) into the right atrium. Note internal vascularity . This mass prolapses through the tricuspid valve into the right ventricle, and there is right heart enlargement. (Right) Axial CECT of the abdomen in the same patient shows the sarcoma invading the IVC. If contrast mixing artifact is possible in the setting of an intravascular abnormality, delayed imaging is confirmatory.

(Left) Axial CECT of a patient with lung cancer shows a centrally necrotic pulmonary mass in the right middle lobe. Note the direct transvenous mass extension via right pulmonary veins into the left atrium . (Right) Sagittal reformation CECT of a patient with metastatic pancreatic cancer shows a tumor thrombus ascending into the right atrium via the IVC. Imaging or reformatting in multiple planes may help to avoid an artifact and can facilitate surgical planning in cases of resectable tumor. P.6:13

TERMINOLOGY Synonyms  Transvenous cardiac metastasis  Cavoatrial extension Definitions  Extracardiac tumor invading atria, typically through growth along venous structures IMAGING General Features  Best diagnostic clue o Intraatrial mass contiguous with extracardiac mass  Location 450

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Typically exophytic within atrial chamber Transvenous extension of tumor from several sources  Superior vena cava (SVC): Lung cancer, mediastinal tumors  Inferior vena cava (IVC): Hepatic, renal, and adrenal tumors  Pulmonary veins: Lung cancer, pulmonary metastases  Morphology o Tumor thrombus typically fills and expands the involved venous structure o Tumors extending into atria often protrude into chamber and appear lobulated or pedunculated Radiographic Findings  Enlargement of cardiac silhouette may be secondary to chamber dilation from outflow obstruction or pericardial effusion  Findings (e.g., pulmonary edema, pleural effusions) may mimic congestive heart failure  Widening of superior mediastinum in cases of SVC invasion or SVC syndrome  Pulmonary or osseous involvement by distant metastases  Elevation of hemidiaphragm in cases of IVC involvement and ascites, congestive hepatomegaly, or bulky hepatic disease  Mediastinal lymphadenopathy may be present CT Findings  NECT o Tumor thrombus is not well evaluated on NECT o Intravenous tumor may expand the vein o Atrial dilation may occur if mass causes outflow obstruction o Primary mass may be detected o Portal vein enlargement and ascites  CECT o Delayed phases (90 seconds) are needed for optimal right heart visualization o Better evaluation than NECT of both primary tumor and tumor extension into atria o May depict vascularity or enhancement of tumor thrombus o Massive collateral varices may enhance  CTA o Allows detection of pulmonary emboli  Cardiac gated CTA o May show valvular involvement or prolapse into ventricle during cardiac cycle if retrospectively gated MR Findings  T1WI o Intraatrial tumor thrombus is typically hypointense relative to myocardium  T2WI o Triple-inversion recovery images assess for edema or necrosis within tumor thrombus  MRV o Evaluates intraluminal extent of disease  SSFP cine o Intraatrial mass may be pedunculated o May show valvular involvement or prolapse into ventricle during cardiac cycle o High spatial resolution images are useful for mobile, intrachamber masses  Delayed enhancement o Gadolinium may accumulate in regions of necrosis or fibrosis in tumor or as a result of hyperemia of tumor o Tumor enhancement is important in differentiating tumor from bland thrombus that may be associated  1st-pass perfusion may demonstrate vascularity  High inversion time (600-800 milliseconds) turbo-type spoiled gradient-echo single-shot magnitude images may differentiate bland thrombus from tumor o Signal from bland thrombus is nulled at high inversion times Imaging Recommendations  Best imaging tool o Transesophageal echocardiography (TEE) is often 1st study to evaluate IVC and atrial extension o Cardiac MR is best tool to differentiate bland thrombus from tumor thrombus 451

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Protocol advice o Imaging or reformatting in several planes is important in avoiding artifact and in surgical planning o Cine imaging is important to depict apparent attachment to atrial wall o Consider 2-minute delayed CT imaging or MR if venous contrast mixing artifact is a possibility o MR: Dynamic perfusion, delayed enhancement, and MRV may help in differentiating bland thrombus from tumor thrombus and in defining exact anatomic boundaries of tumor Angiographic Findings  Filling defect within IVC or SVC  May show tumor vascularity and allow for preoperative tumor embolization, particularly in renal cell carcinoma (RCC) Echocardiographic Findings  TEE is 1st imaging choice in suspected right atrial tumor extension  May be contraindicated in cases complicated by significant esophageal varices DIFFERENTIAL DIAGNOSIS Thrombus  Atrial fibrillation (left atrium) and central venous catheters (right atrium) are common causes P.6:14  Predilection for left atrial appendage in atrial fibrillation  Myocardial scars are independent risk factors for intracardiac thrombus formation  Intrachamber tumors may have associated bland thrombus Pseudothrombosis  Inhomogeneous mixing of contrast-opacified and nonopacified blood in IVC and right atrium may mimic mass on CT  2-minute delayed CT imaging or MR for confirmation  Characteristic laminar flow pattern from renal veins Myxoma  Most common primary cardiac tumor  Typically located in left atrium, although location and morphology vary  Characteristic stalk-like attachment to interatrial septum near foramen ovale Other Primary Cardiac Tumors  Malignant primary cardiac tumors are very rare o Sarcomas most commonly arise from right heart and may invade venous structures o Leiomyosarcoma is usually sessile and originates from posterior wall of left atrium, frequently invading pulmonary veins Pseudolipoma  Pseudolesion of IVC from pericaval fat above caudate lobe  More common in chronic liver disease PATHOLOGY General Features  Associated abnormalities o Tumor emboli to lungs may occur o Deep venous thrombosis Staging, Grading, & Classification  Varying amounts of penetration into walls of IVC and cardiac structures  Tumor extension into atria typically indicates stage III or IV disease o RCC: Spread into large veins to the heart is T3c or stage III, although tumor invasion into cardiac structures may be considered stage IV o Lung cancer: Left atrial involvement is T4 disease, stage IIIB  5-year survival rates from resection of selective locally invasive tumors: ˜ 10-30% CLINICAL ISSUES Presentation  Most common signs/symptoms o May remain asymptomatic until obstruction occurs o Syncope o Heart failure, edema, dyspnea o Arrhythmia 452

Diagnostic Imaging Cardiovascular o Pansystolic murmur, diastolic rumble of tricuspid valve Other signs/symptoms o Budd-Chiari syndrome, ascites, hepatomegaly o SVC syndrome is possible o Symptoms may improve with left lateral decubitus position o Abdominal pain, anorexia, weight loss Demographics  Epidemiology o Intracardiac extension of tumors overall is rare o Most common tumors include  Renal cell carcinoma  Most common cause of transvenous metastatic disease to the heart  4-10% have tumor thrombus; 1% has extension into right atrium  Hepatocellular carcinoma (HCC)  2% have transvenous atrial extension at autopsy  Lung cancer  Adrenocortical carcinoma  Uterine cancers  Mediastinal masses  Thymic tumors  Thyroid carcinoma has also been reported  Vascular origin tumors  Leiomyoma, leiomyosarcoma Natural History & Prognosis  Poor prognosis in cases of malignant tumor extension o Median survival for HCC patients: 1-4 months  Potential cardiac outflow obstruction Treatment  Penetration into walls of IVC and cardiac structures is variable, complicating surgical planning  Dependent on histology, coagulopathy, portal hypertension o RCC: Radical nephrectomy and tumor thrombectomy o HCC: Thalidomide and surgical debulking  Surgical reintervention may not be offered for recurrent or residual disease DIAGNOSTIC CHECKLIST Consider  Tumor extension of extracardiac tumors when intraatrial mass approximates venous inflow structure Image Interpretation Pearls  Evaluate for associated bland thrombus as intraatrial tumors may cause turbulent blood flow  Pulmonary emboli may complicate intraatrial tumors Reporting Tips  Accurately localize tumor thrombus margins  Tumor extension into atria will often significantly alter surgical planning and complicate radiation therapy o Apparent attachment of tumor thrombus to atrial wall is particularly important in surgical planning  Valvular involvement is important for operative planning SELECTED REFERENCES 1. Buckley O et al: Cardiac masses, part 2: key imaging features for diagnosis and surgical planning. AJR Am J Roentgenol. 197(5):W842-51, 2011 P.6:15 

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(Left) Axial CECT of a patient with hepatocellular carcinoma shows a low-attenuation lobular heterogeneously enhancing mass extending through the IVC into the right atrium. (Right) Coronal reformation CECT of the same patient shows the primary hepatic mass , associated ascites, and a pulmonary metastasis . Obstruction of hepatic venous drainage may result in Budd-Chiari syndrome in patients with extensive disease. Note right atrial tumor extension .

(Left) Axial CECT of a patient with retroperitoneal leiomyosarcoma shows a vascular mass extending through the IVC into the right atrium. Note collateral venous enlargement of azygos system secondary to obstruction of the IVC. Tumor vascularity can be difficult to differentiate from calcification, but noncontrast or delayed-phase imaging will differentiate. (Right) Sagittal reformation CECT of the same patient shows the primary mass below the diaphragm causing enlargement of the IVC.

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(Left) Axial CECT of a patient with an invasive pelvic leiomyoma shows a lobulated mass in the right atrium. Outflow obstruction may lead to chamber enlargement, and the right atrium is dilated in this case. (Right) Coronal reformation CECT of the same patient shows the extent of tumor thrombus within the IVC and the primary pelvic mass . Extension into the atrium is an important finding as it significantly alters the surgical plan.

Atrial Myxoma Atrial Myxoma Suhny Abbara, MD, FSCCT Christopher M. Walker, MD John P. Lichtenberger, III, MD Key Facts Imaging  Myxomas are most common of all primary cardiac neoplasms  Intracavitary mass originating from interatrial septum near fossa ovalis  60-75% in left atrium; followed by right atrium  CT o Typically low-attenuation intracavitary mass o Calcification in ˜ 50% of right atrial myxomas  MR o Heterogeneous mass, heterogeneous enhancement o May change position during cardiac cycle o May exhibit stalk; may prolapse through or obstruct atrioventricular valve o Cine SSFP to evaluate mobility, valvular obstruction, and flow acceleration  Echocardiography is generally initial imaging modality  MR is optimal imaging modality for evaluation of myxoma Top Differential Diagnoses  Intracardiac thrombus  Cardiac metastasis  Cardiac lipoma  Primary malignant cardiac tumor Clinical Issues  ˜ 60% of affected patients are female  Treated with surgical resection; 3-year survival > 95% Diagnostic Checklist  Consider cardiac myxoma in patients with well-defined noninvasive atrial mass  Stalk-like connection to interatrial septum may be evident on cross-sectional imaging  Risk of systemic embolization if left atrial myxoma

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(Left) Graphic shows typical morphologic features of cardiac myxoma with a thin short stalk connecting the heterogeneous left atrial mass to the interatrial septum. Large lesions may obstruct the mitral valve during systole (ball-valve mechanism). (Right) Axial CECT of a patient with a left atrial myxoma shows a heterogeneous left atrial mass with smooth borders, internal vascularity, and characteristic attachment to the interatrial septum near the fossa ovalis.

(Left) Composite image of PA (left) and lateral (right) chest radiographs shows an ovoid right atrial myxoma with peripheral curvilinear calcification . Right atrial myxomas are more likely to exhibit calcification (˜ 50%) than left atrial myxomas. (Right) Vertical long-axis (2-chamber) cardiac CT shows a round mass in the left atrium. Note the long pedicle . P.6:17

TERMINOLOGY Definitions  Most common of all primary cardiac neoplasm IMAGING General Features  Location o ˜ 60-75% in left atrium, followed by right atrium o Rare sites: Ventricle, inferior vena cava, valve, pulmonary artery/vein  Size o 1-15 cm diameter (mean = 5.8 cm at pathology)  Morphology 456

Diagnostic Imaging Cardiovascular o Usually solitary; may be multiple in familial forms o Ovoid/round lesion with lobular or smooth contours Radiographic Findings  Rarely exhibit calcification if left atrial  About 50% of right atrial myxomas calcify  Findings may mimic atrioventricular valve stenosis CT Findings  NECT o Low-attenuation intracavitary mass  Occasionally cystic  May change position during cardiac cycle o Calcification in ˜ 50% of right atrial myxomas, rare in left atrial myxomas  CECT o May exhibit heterogeneous contrast enhancement MR Findings  Majority are heterogeneous on MR o Iso- or hypointense on T1WI o Usually hyperintense on T2WI  Heterogeneous low-grade enhancement  Cine SSFP images: Evaluation of mobility, valve obstruction, flow acceleration, stalk visualization Echocardiographic Findings  Tumor typically hyperechoic  Assessment of tumor mobility and cardiac physiology Nuclear Medicine Findings  May be mildly FDG avid  If very FDG avid, consider malignancy DIFFERENTIAL DIAGNOSIS Intracardiac Thrombus  Common; usually in posterolateral atrium or appendage  Associated with atrial fibrillation & mitral valve disease  Acute thrombus does not enhance; chronic thrombus may have slight peripheral enhancement  No prolapse through mitral valve  Both thrombus and myxoma can be mobile Cardiac Metastasis  More often multiple and enhancing  Often associated with pericardial effusion, lymphadenopathy, or other metastases Primary Malignant Cardiac Tumor  Most often angiosarcoma  May exhibit pericardial effusion, lung metastases Papillary Fibroelastoma  Most common tumor of valvular epithelium  Usually solitary and ≤ 1 cm  Usually arises on aortic or mitral valve PATHOLOGY General Features  Genetics o 90% sporadic o Carney complex: Familial cardiac myxoma (< 10%) Gross Pathologic & Surgical Features  Usually soft gelatinous or friable frond-like tumor  80% of cases exhibit hemorrhage, thrombus, or hemosiderin CLINICAL ISSUES Presentation  Most common signs/symptoms o Symptoms of valvular obstruction (40%) o Constitutional (30%): Fatigue, weight loss, fever o Arrhythmias or other electrocardiographic changes o Peripheral embolization (stroke, myocardial infarction) 457

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May be associated with auscultation abnormalities  Mimics mitral valve disease  Tumor plop in about 15% of cases

Demographics  Age o Mean age at presentation: 50 years o Range: 1 month to 81 years  Gender o ˜ 60% of affected patients are female Natural History & Prognosis  Very slow growth, 3-year survival rate > 95% Treatment  Surgical resection, traditionally via sternotomy  May recur after removal in 5% of cases  Newer minimally invasive techniques promising DIAGNOSTIC CHECKLIST Consider  Cardiac myxoma in patients with well-defined noninvasive atrial mass SELECTED REFERENCES 1. Buckley O et al: Cardiac masses, part 2: key imaging features for diagnosis and surgical planning. AJR Am J Roentgenol. 197(5):W842-51, 2011 2. Scheffel H et al: Atrial myxomas and thrombi: comparison of imaging features on CT. AJR Am J Roentgenol. 192(3):639-45, 2009 3. Grebenc ML et al: Cardiac myxoma: imaging features in 83 patients. Radiographics. 22(3):673-89, 2002 P.6:18

Image Gallery

(Left) Four-chamber view SSFP MR shows a round right atrial mass closely apposed to the interatrial septum. (Right) Four-chamber view T2WI MR in the same patient shows a uniform high T2 signal within the mass, indicating high water content. Myxoma is the most common primary benign cardiac tumor and is distinguished from thrombus by enhancement with gadolinium and increased or heterogeneously high T2 signal, as seen in this case.

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(Left) Four-chamber view T1WI C+ FS MR shows heterogeneous enhancement within the right atrial mass. There is a small stalk connecting the mass to the interatrial septum. (Right) Composite image of 4-chamber cine SSFP in systole (top) and diastole (bottom) shows a large left atrial myxoma attached to the interatrial septum that prolapses through and obstructs the mitral valve during diastole, an uncommon but characteristic and distinguishing feature from thrombus.

(Left) Oblique coronal cardiac CT shows high-density contrast in the superior vena cava outlining a mass within the right atrium. (Right) Oblique axial cardiac CT from the same patient shows the oval-shaped mass with punctate calcifications adjacent to the interatrial septum. The right atrium is the 2nd most common location for intracardiac myxoma. P.6:19

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(Left) Four-chamber view SSFP MR shows a round, low signal intensity left atrial mass located immediately adjacent to the interatrial septum. (Right) Four-chamber view late gadolinium enhancement (LGE) MR from the same patient shows mostly low signal in the mass, indicating no late enhancement. The characteristic location makes atrial myxoma the most likely diagnosis in this case.

(Left) Axial CECT shows multiple pulmonary tumor emboli in a patient with a right atrial myxoma. (Right) Axial CECT in the same patient shows a lobulated, frond-like right atrial mass arising from the interatrial septum , which was an atrial myxoma. Note the pulmonary artery filling defects consistent with tumor emboli .

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(Left) LVOT SSFP MR shows lobulated thickening of the mitral valve leaflet. The major differential considerations for a valvular mass are vegetations in the setting of endocarditis, thrombus, and papillary fibroelastoma. (Right) Vertical long-axis (2-chamber) SSFP MR in the same patient shows lobulated thickening of the mitral valve leaflet. At surgery, this was proven to represent a rare degenerating myxoma of the mitral valve. LA = left atrium; LV = left ventricle.

Cardiac Lipoma Cardiac Lipoma Suhny Abbara, MD, FSCCT Christopher M. Walker, MD Key Facts Terminology  Benign encapsulated cardiac mass composed of mature adipocytes Imaging  Follows fat density on all MR pulse sequences  May protrude into chamber lumen when arising from endocardium  May grow within pericardial space when arising from epicardium  Multiple fat-containing masses have been described in tuberous sclerosis  Fat density (< -50 HU) on CT within otherwise water density or soft tissue density cardiac chambers/myocardium  No signs of invasion  Rarely originates within left ventricular myocardium  No significant enhancement  If soft tissue component, consider liposarcoma or teratoma as alternate diagnosis Top Differential Diagnoses  Atrial myxoma  Cardiac or pericardial teratoma  Other primary benign tumors  Liposarcoma  Thrombus  Lipomatous hypertrophy of interatrial septum Clinical Issues  May be asymptomatic  May cause arrhythmias  Subepicardial tumors may cause compression symptoms  Intraluminal subendocardial tumors may cause location-specific symptoms, such as obstruction or syncope

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Diagnostic Imaging Cardiovascular

(Left) Short-axis cardiac CT shows a large filling defect within the left ventricle (LV) cavity that is of fat density and adheres to the lateral wall of the left ventricle in a patient with decreased ventricular function and palpitations. (Right) Four chamber view cardiac CT in the same patient shows broad attachment of the low-attenuation mass to the lateral LV wall and papillary muscles. The mass was resected surgically due to symptoms and was confirmed to be a lipoma. (Courtesy B. Ghoshhajra, MD.)

(Left) Short-axis T1WI FSE MR in the same patient shows high signal intensity of the mass , similar to that of nearby epicardial fat . (Right) LVOT view from a retrospectively gated cardiac CT shows a hypodense mass in the anteroseptal wall of the left ventricle. The mass has a density similar to subcutaneous fat and became more rounded during systole. This suggests that the mass is composed of tissue that is softer than the surrounding myocardium and contains fat. P.6:21

TERMINOLOGY Definitions  Benign encapsulated cardiac mass composed of mature adipocytes IMAGING General Features  Best diagnostic clue o Follows fat density on all MR pulse sequences o Fat attenuation on CT (negative HU)  Location o Common locations are epicardial, endocardial, interatrial septum, right atrium (RA), and left ventricle (LV) 462

Diagnostic Imaging Cardiovascular o o o o o

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May protrude into chamber lumen when arising from endocardium May grow within pericardial space when arising from epicardium Rarely intramyocardial Rarely arise from valves Rarely multiple cardiac lipomas  Multiple fat-containing masses have been described in tuberous sclerosis  Recent pathologic literature calls to question whether these truly represent lipomas or are simply unencapsulated fat cells

Size

o Variable, ranging from few millimeters to > 15 cm o Often large at time of diagnosis  Morphology o Sessile or polypoid encapsulated mass with sharp demarcation o Fat density on CT, typical fat signal on MR Radiographic Findings  Radiography o Chest radiography findings  Usually normal  ± signs of valve obstruction distal to lipoma if intracavitary  May present as mass contiguous with pericardium  ± calcifications  ± nonspecific cardiomegaly CT Findings  NECT o Fat density (< -50 HU) within otherwise water density or soft tissue density cardiac chambers/myocardium o Dilatation of obstructed chambers/vasculature  CECT o Fat density mass usually predominantly intraluminal or in epicardial space  Filling defect on contrast-enhanced CT o Rarely originates within LV myocardium o No significant enhancement o No signs of invasion o ± thin nonenhancing septation MR Findings  T1WI o Bright mass with dark capsule on T1WI (capsule may be inapparent) o May demonstrate few thin septations o Fat-saturation images demonstrate signal dropout of mass  T2WI o Follows fat signal  PD/intermediate o Follows fat intensity  T1WI C+ o No significant enhancement  MRA o Filling defect in cardiac chambers  Lipomatous hypertrophy of interatrial septum has bilobed appearance due to relative sparing of fossa ovalis and does not have capsule Echocardiographic Findings  Echocardiogram o Sensitive tool to demonstrate extent and effect on cardiac function o Echogenic intraluminal spherical or polypoid mass o Usually broad-based attachment and not very mobile o Transesophageal echocardiography helpful in guiding transvenous biopsy in equivocal cases Angiographic Findings  Conventional o Nonspecific intraatrial or intraventricular filling defect Nuclear Medicine Findings 463

Diagnostic Imaging Cardiovascular 

PET o o

Usually no uptake Lipomatous hypertrophy of interatrial septum often has FDG avidity on PET  Increased uptake is due to presence of brown fat  Not a true neoplasm Imaging Recommendations  Best imaging tool o MR or CT are usually diagnostic  Protocol advice o Fat saturation of T1WI helpful in characterizing fat content and visualizing capsule and potential nonfatty components of masses  If solid nonfatty components are present, consider alternative diagnoses (teratoma, liposarcoma, etc.) DIFFERENTIAL DIAGNOSIS Atrial Myxoma  Most common benign primary tumor  Typically occurs in left atrium  Hypointense on T1 Cardiac or Pericardial Teratoma  Rare tumors, usually present in infancy  ± large amount of fat  May have mature tissues from all 3 germ cell layers  ± cardiac compression or pericardial effusion Other Primary Benign Tumors  Usually readily distinguished by signal characteristics on MR Liposarcoma  Very rare  May show invasion of neighboring structures P.6:22  May become symptomatic from obstructive symptoms  4 pathological types: Well-differentiated, myxoid, round cell, pleomorphic Other Malignant Tumors  Metastatic disease  Readily distinguished by signal characteristics on MR and density on CT Thrombus  Common locations o Left atrial appendage, ventricular apex following infarct  Usually does not follow signal characteristics of epicardial fat on all sequences Lipomatous Hypertrophy of Interatrial Septum  Not a true neoplasm  No capsule, which distinguishes it from lipoma pathologically  Contains brown fat  Dumbbell appearance of atrial septum due to sparing of fossa ovalis  May demonstrate FDG uptake on PET PATHOLOGY General Features  True cardiac lipomas are rare o 2nd most common benign primary cardiac neoplasms  Most common benign primary cardiac neoplasms are myxomas  Most common of all (benign or malignant) primary neoplasms are sarcomas  Most common mass is thrombus  Most common neoplasms (primary or secondary) are metastases  Usually single subendocardial, myocardial, or subpericardial homogeneous circumscribed tumor Gross Pathologic & Surgical Features  Most are spherical, sessile, or polypoid masses of homogeneous yellow fat  Usually 1-15 cm; may be as massive as 4,000 g 464

Diagnostic Imaging Cardiovascular o Subepicardial tumors often grow to larger sizes o Subendocardial tumors are usually small and have broad attachment Microscopic Features  True lipomas are encapsulated and contain neoplastic mature adipocytes  Lipomas do not contain brown fetal fat cells o Lipomatous hypertrophy of interatrial septum is characterized by infiltration of mature adult-type or fetal fat cells between myocardial fibers with absence of capsule CLINICAL ISSUES Presentation  Most common signs/symptoms o Symptoms depend on location and size of mass  May be asymptomatic  May cause arrhythmias  Subepicardial tumors may cause compression symptoms  Intraluminal subendocardial tumors may cause location-specific symptoms, such as obstruction or syncope  Other signs/symptoms o Rare reports of sudden cardiac death Demographics  Epidemiology o All ages, equal sex distribution o More common in overweight patients Natural History & Prognosis  Frequently incidentally noted on autopsy  May cause progressive obstructive or compressive symptoms requiring surgery  Generally good outcome  Recurrences post surgery are rare Treatment  No treatment necessary if asymptomatic  Surgical resection if symptomatic DIAGNOSTIC CHECKLIST Consider  Repeat T1WI with fat saturation to prove fatty content Image Interpretation Pearls  If soft tissue component, consider liposarcoma or teratoma as alternate diagnosis SELECTED REFERENCES 1. Girrbach F et al: Epicardial lipoma—a rare differential diagnosis in cardiovascular medicine. Eur J Cardiothorac Surg. 41(3):699-701, 2012 2. Adriaensen ME et al: Mature fat cells in the myocardium of patients with tuberous sclerosis complex. J Clin Pathol. 64(3):244-5, 2011 3. Rajiah P et al: Multimodality imaging of an unusual case of right ventricular lipoma. Circulation. 124(17):1897-8, 2011 4. Adriaensen ME et al: Fatty foci in the myocardium in patients with tuberous sclerosis complex: common finding at CT. Radiology. 253(2):359-63, 2009 5. Kosar F et al: A case of a large intrapericardial lipoma occupying pericardial space. J Card Surg. 22(5):427-9, 2007 6. Matsushita T et al: Aortic valve lipoma. Ann Thorac Surg. 83(6):2220-2, 2007 7. Taori K et al: Intrapericardial teratoma diagnosed on CT. J Thorac Imaging. 22(2):185-7, 2007 8. Ou P et al: Images in cardiovascular medicine. Cardiac teratoma in a newborn with right ventricular outflow tract obstruction. Circulation. 113(2):e17-8, 2006 9. Kato S et al: [Cardiac liposarcoma at the right ventricular outflow tract (RVOT) following lipomatous hypertrophy of the interatrial septum (LHIS); report of a case] Kyobu Geka. 57(2):143-6, 2004 10. Uemura S et al: Extensive primary cardiac liposarcoma with multiple functional complications. Heart. 90(8):e48, 2004 11. Frank H: Cardiac and paracardiac masses. In Manning WJ et al: Cardiovascular Magnetic Resonance. Philadelphia: Churchill Livingstone, 2002 12. Gaerte SC et al: Fat-containing lesions of the chest. Radiographics. 22 Spec No:S61-78, 2002 13. Grebenc ML et al: Primary cardiac and pericardial neoplasms: radiologic-pathologic correlation. Radiographics. 20(4):1073-103; quiz 1110-1, 1112, 2000 P.6:23 465

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Image Gallery

(Left) Short-axis T1WI MR shows a small, high signal intensity oval lesion in the myocardium of the upper interventricular septum, similar in signal intensity to nearby epicardial fat . (Right) Short-axis T1WI fat suppressed MR from the same patient shows complete signal loss in the oval lesion with the application of fat suppression. This confirms presence of fat and is consistent with an intramyocardial lipoma.

(Left) Axial NECT shows a well-defined fat-attenuation mass within the interventricular septum. (Right) Axial NECT in the same patient shows multiple lobulated masses arising from the anterior and posterior left kidney. The masses contain macroscopic fat and are diagnostic of angiomyolipomas. The presence of multiple angiomyolipomas is most commonly associated with tuberous sclerosis.

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(Left) Axial NECT in the same patient shows a small round fat-containing lesion in the posterior right hepatic lobe. This is most consistent with an angiomyolipoma in this patient with known tuberous sclerosis. (Right) Axial NECT in the same patient shows numerous round and oval lung cysts distributed diffusely throughout the lungs. This patient had lymphangioleiomyomatosis associated with tuberous sclerosis.

Cardiac Thrombus Cardiac Thrombus Suhny Abbara, MD, FSCCT Ali Karaosmanoglu, MD Key Facts Terminology  Thrombus within a cardiac chamber typically resulting from flow disturbance or akinetic or dyskinetic wall due to prior infarct/aneurysm or cardiomyopathy Imaging  Intraluminal filling defect  Nonenhancing mural rim of tissue lining infarction  Underlying infarct may be evident from myocardial thinning, linear myocardial calcification, linear subendocardial fatty metaplasia, aneurysm, or wall-motion abnormality  Left ventricle mural thrombus in 40-60% of patients with anterior myocardial infarction if no anticoagulant therapy  Thrombus is usually 35-50 HU, whereas remote normal myocardium is 80-100 HU  Left atrium thrombus is common in atrial fibrillation and mitral stenosis  May demonstrate calcification if old thrombus  Delayed contrast-enhancement spoiled gradient-echo technique is highly sensitive for detecting intracardiac thrombus  If thrombus is suspected, long inversion time (TI = 600 milliseconds) has been shown to be most decisive Pathology  Thrombus is most frequent intracardiac mass  Central layers: Fibroblasts, macrophages o May be organized  Superficial layers: Fibrin, platelets, and red blood cells Clinical Issues  Left chambers: Stroke, systemic emboli  Right chambers: Pulmonary emboli

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Diagnostic Imaging Cardiovascular

(Left) Three-chamber view LGE MR shows large anterior-apical LAD territory transmural left ventricle (LV) infarct with aneurysm formation and a broadly attached signal void mass within the lumen, consistent with LV thrombus. (Right) Short-axis LGE MR (same patient) shows the transmural abnormal late hyperenhancement and thinning of the myocardium, which indicates remote infarct. Nonenhancing broadly attached thrombus along the anterior septum is present. Matching dyskinesia was evident on cine images.

(Left) Axial CECT shows 4-chamber enlargement and an apical low-attenuation LV filling defect consistent with LV thrombus in the setting of nonischemic cardiomyopathy. Note normal papillary muscle and normal-thickness LV wall without fatty metaplasia or calcification. (Right) Frontal angiography of lower extremity shows an abrupt cutoff of popliteal artery with filling of several collateral arteries due to embolic occlusion. P.6:25

TERMINOLOGY Definitions  Thrombus within cardiac chamber typically resulting from flow disturbance or akinetic or dyskinetic wall due to prior infarct/aneurysm or cardiomyopathy IMAGING General Features  Best diagnostic clue o Intraluminal filling defect  In setting of infarct or dilated hypokinetic myopathic ventricle o Nonenhancing mural rim of tissue lining infarction

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Diagnostic Imaging Cardiovascular 

Underlying infarct may be evident from myocardial thinning, linear myocardial calcification, linear subendocardial fatty metaplasia, aneurysm, or wall-motion abnormality



Location o Left ventricle (LV) mural thrombus in 40-60% of patients with anterior myocardial infarction if no anticoagulant therapy  Size o Variable  Morphology o Broad-based lining akinetic wall if due to LV infarct/aneurysm o May be ovoid or lobular intraluminal mass or filling defect  May be pedunculated with connection to wall  Mobile Radiographic Findings  Radiography o Chest radiography  Only clue may show calcifications projected over infarcted area  May demonstrate bulge from LV aneurysm CT Findings  NECT o May demonstrate calcification if old thrombus  CECT o Filling defect and underlying signs of LV infarction o Mural thrombus may mimic wall of normal thickness  Look for signs of infarction (calcium or fatty metaplasia)  Thrombus appears slightly lower in attenuation compared to remote normal myocardium  Cardiac gated CTA o Wall motion abnormality in underlying myocardium o May demonstrate mobility of pedunculated thrombi o Underlying chronic infarction, aneurysm, or pseudoaneurysm may be most obvious finding  Laminated mural thrombus may be subtle finding o Thrombus is usually 35-50 HU, whereas remote normal myocardium is 80-100 HU MR Findings  Increased signal on spin-echo sequences o Pitfall: Slow-flowing blood may also have increased signal on spin-echo sequences  Delayed contrast-enhanced spoiled gradient-echo technique is highly sensitive for detecting intracardiac thrombus o If thrombus is suspected, long inversion time (TI = 600 milliseconds) has been shown to be most decisive  No enhancement of thrombus on 1st-pass perfusion or delayed-enhancement images  May be difficult to differentiate from other atrial or ventricular masses  Usually related findings from infarction o Subendocardial defect in coronary territory on 1st-pass perfusion imaging o Subendocardial or transmural delayed hyperenhancement o Myocardial thinning o Hypokinesia, akinesia, or dyskinesia o Aneurysm or pseudoaneurysm Echocardiographic Findings  Echocardiogram o First-line technique for ventricular thrombus  70-80% sensitive; 90-95% specific o Ventricular thrombi are usually anterior and apical o May be laminar and adherent to wall or pedunculated and mobile echogenic masses in areas of hypokinesis o Criteria for increased risk of embolization  Increased mobility, protrusion into ventricular chamber  Visualization in multiple views  Contiguous zones of akinesis and hyperkinesis o Experimental use of antifibrinogen-labeled echogenic immunoliposomes for thrombus-specific enhancement of echogenicity 469

Diagnostic Imaging Cardiovascular Angiographic Findings  Conventional o Filling defect may be free floating (atrial thrombus ball) o May be negative if thrombus is broadly adherent to wall  Only hint may be presence of wall-motion abnormality on ventriculography Imaging Recommendations  Best imaging tool o MR, CT, or contrast echo Image-Guided Biopsy  Biopsy performed to differentiate a neoplasm from benign thrombus may be false negative for neoplasm if mass is covered with reactive thrombus DIFFERENTIAL DIAGNOSIS Benign Neoplasm  Frequently intraluminal extension  Contrast enhancement excludes fresh thrombus  Organized thrombus may demonstrate low-grade enhancement Primary or Secondary Malignancy  Invasion of atrial or ventricular wall and contrast enhancement exclude thrombus Vegetation  Requires antibiotics P.6:26

Pannus  Typically related to prosthetic valve replacements Apical Hypertrophic Cardiomyopathy  Thickening of actual myocardium near apex without nonenhancing luminal filling defect Left Ventricle Noncompaction or Prominent Normal Trabeculation  May mimic mural thrombus Papillary Muscles  Move concordant with valve motion Technical Artifacts  Not persistent on multiple views  Absence of wall-motion abnormality or stasis PATHOLOGY General Features  Etiology o Right atrium thrombus  Low cardiac output state  Atrial fibrillation  Central catheters or pacemaker wires, transvenous ablation procedures  Embolic thrombus from deep venous thrombosis or extension of tumor-thrombus from kidney, liver, or adrenal glands  Rheumatic tricuspid stenosis, heart surgery, cardiomyopathy, or extension of tumorthrombus from kidney, liver, or adrenal glands  Heart surgery  Cardiomyopathy o Right ventricle thrombus  Rare; same as right atrium thrombus o LA thrombus  Atrial fibrillation is most common  Mitral stenosis  LA appendage is most common site within LA to harbor thrombus o LV thrombus  Myocardial infarction, LV aneurysm o Rarely, LV thrombosis may present as sequela of chemotherapy or in patients exposed to toxic substances (e.g., carbon monoxide)

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LV apical thrombus may be sequela of Takotsubo cardiomyopathy (stress-induced transient “apical ballooning” akinesis) or other nonischemic cardiomyopathy o May develop in context of paraneoplastic syndrome  Most frequent intracardiac mass Gross Pathologic & Surgical Features  Freshly thrombosed blood at surface  May have organized thrombus in deep layers Microscopic Features  May be layered and adherent to myocardium  Central layers: May be organized o Fibroblasts o Macrophages  Superficial layers: Fibrin, platelets, and red blood cells CLINICAL ISSUES Presentation  Symptoms of underlying condition o Most frequently myocardial infarction  Ventricular aneurysm o Cardiomyopathy  May be asymptomatic until complication occurs  Left chambers: Stroke, peripheral emboli o 10% of mural LV thrombi result in systemic emboli  Right chambers: Pulmonary emboli Demographics  Age o Parallels myocardial infarction as most common underlying cause Natural History & Prognosis  Mural thrombus formation within 48-72 hours post myocardial infarction carries poor prognosis from associated complications  Found in 30-40% of anterior myocardial infarction but in < 5% of inferior myocardial infarction Treatment  Anticoagulation for 3-6 months with warfarin o Observational studies suggest some benefit in prevention of thromboembolism  Aspirin may prevent further platelet deposition  Percutaneous left atrial appendage transcatheter occlusion in high-risk patients with atrial fibrillation to prevent stroke DIAGNOSTIC CHECKLIST Consider  If a presumed thrombus does not resolve with anticoagulation, consider differential diagnoses Protocol Advise  Prescribe 1st-pass perfusion MR and delayed-enhancement sequences in imaging plane that best demonstrates thrombus (often long-axis plane) SELECTED REFERENCES 1. Romero J et al: Detection of left atrial appendage thrombus by cardiac computed tomography in patients with atrial fibrillation: a meta-analysis. Circ Cardiovasc Imaging. 6(2):185-94, 2013 2. Bittencourt MS et al: Left ventricular thrombus attenuation characterization in cardiac computed tomography angiography. J Cardiovasc Comput Tomogr. 6(2):121-6, 2012 3. Weinsaft JW et al: LV thrombus detection by routine echocardiography: insights into performance characteristics using delayed enhancement CMR. JACC Cardiovasc Imaging. 4(7):702-12, 2011 4. Weinsaft JW et al: Detection of left ventricular thrombus by delayed-enhancement cardiovascular magnetic resonance prevalence and markers in patients with systolic dysfunction. J Am Coll Cardiol. 52(2):148-57, 2008 5. Rustemli A et al: Evaluating cardiac sources of embolic stroke with MRI. Echocardiography. 24(3):301-8; discussion 308, 2007 6. Fieno DS et al: Cardiovascular magnetic resonance of primary tumors of the heart: a review. J Cardiovasc Magn Reson. 8(6):839-53, 2006 P.6:27

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Diagnostic Imaging Cardiovascular Image Gallery

(Left) Axial CECT shows an artifact from an implantable cardioverter-defibrillator in the right ventricle and left ventricle apical wall thinning , linear calcification, and a small soft-tissue density just inside the calcification, typical of remote myocardial infarction with luminal thrombus formation. (Right) Sagittal CECT (same patient) shows wall thinning and calcification with a suggestion of left ventricle aneurysm. Note that the thin low-density rim lining the infarct indicates thrombus.

(Left) SSFP image in a 3-chamber view shows a low-signal thrombus adherent to the mid anteroseptal and inferolateral walls, which correspond to different coronary territories. Note large left pleural effusion . (Right) Axial image from a contrast-enhanced cardiac CT in a patient with Loeffler endocarditis shows low-density thrombus within the left ventricular mid cavity and apex and to a lesser degree at the base . Note large left pleural effusion and lower lobar atelectasis.

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(Left) Four-chamber LGE MR image shows diffuse left and right ventricular subendocardial delayed hyperenhancement spanning all coronary territories and a nonenhancing ventricular thrombus in a patient with Loeffler endocarditis. (Right) Short-axis LGE MR shows diffuse subendocardial enhancement in the left and right ventricles and a nonenhancing left ventricle thrombus . P.6:28

(Left) Oblique cardiac CT in a patient 5 hours after onset of chest pain shows complete nonfilling of the LAD coronary artery due to acute proximal plaque rupture or occlusion. Note apical LV filling defect . (Right) Fourchamber view cardiac CT (same patient) with acute myocardial infarct shows hypoperfusion in the LAD territory infarct , normal enhancement in remote myocardium , and apical LV filling defect , which may be due to slow mixing mimicking thrombus or early thrombus.

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(Left) Long-axis cardiac CT in a patient with atrial fibrillation demonstrates a filling defect in the left atrial appendage (LAA) that persisted on delayed imaging, indicating LAA thrombus. Defects that fill in on delayed imaging are due to slow contrast mixing across the LAA. (Right) Two-chamber view SSFP image obtained during systole shows thinning of the left ventricle apex , which was dyskinetic on cine views. A heterogeneous low-signal filling defect is noted and suggestive of thrombus.

(Left) Three-chamber LGE MR (same patient) shows transmural enhancement of the thinned myocardium in the LAD territory, indicating nonviable tissue. Note nonenhancing material at the left ventricular apex, indicative of thrombus. (Courtesy S. Kligerman, MD.) (Right) Two-chamber LGE MR shows a transmural LAD territory left ventricle apical infarct with a nonenhancing thrombus . P.6:29

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(Left) Axial CECT shows a thinned rim of apical myocardium with an aneurysm that is difficult to separate from the thrombus , which is of only slightly lower attenuation. (Right) Axial CECT 3 minutes after injection demonstrates greater difference in attenuation between the thinned myocardium of the aneurysm and the thrombus .

(Left) Axial CECT in late-contrast phase in a patient with cardiomyopathy shows a well-circumscribed low-attenuation filling defect within the dilated right atrial appendage . Note small right and moderate left pleural effusions and left basilar atelectasis. (Right) Axial CECT at level of left atrial appendage (same patient) shows 2 spherical low attenuation filling defects in the left atrial appendage, consistent with thrombus.

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(Left) Vertical long-axis (2-chamber) SSFP cine image shows apical LV myocardial thinning and low signal intensity masses lining the luminal side of the infarct . (Right) Vertical long-axis (2-chamber) LGE MR confirms subendocardial near transmural LV infarct in the LAD territory with aneurysm and mural thrombus . Microvascular obstruction may be difficult to differentiate from small thrombus. Long inversion time (TI = 600 milliseconds) is most helpful for the identification of thrombus.

Cardiac Sarcoma Cardiac Sarcoma Suhny Abbara, MD, FSCCT Christopher M. Walker, MD Brett W. Carter, MD Key Facts Terminology  Most common primary cardiac malignancy  Restricted to heart and pericardium Imaging  Best diagnostic clue: Mass involving cardiac wall &/or chamber  Radiography may be normal or show cardiomegaly  CECT o Discrete hypodense mass involving cardiac wall &/or chambers o Infiltration/invasion: Pericardium, myocardium, mediastinum o Pulmonary metastases  MR o T1: Heterogeneous; necrosis and hemorrhage o T2: Heterogeneously hyperintense o T1 C+: Heterogeneous enhancement Top Differential Diagnoses  Cardiac metastases  Lymphoma  Cardiac myxoma  Thrombus Pathology  Angiosarcoma most common histologic type (37%)  Metastatic disease: 66-89% at presentation Clinical Issues  Dyspnea is most common symptom  Poor prognosis o Mean survival: 3 months to 4 years o Recurrence and metastases within 1 year 476

Diagnostic Imaging Cardiovascular 

Treatment o Surgery: Palliative, may prolong survival o Palliative radiation and chemotherapy

(Left) Graphic demonstrates typical features of cardiac angiosarcoma arising from the lateral right atrial wall, infiltrating the pericardial fat and tricuspid valve, and encasing the right coronary artery (RCA) . (Right) Axial T1W dark blood spin-echo sequence shows a large heterogeneous mass in the right atrium and right atrioventricular groove. The RCA is spared. Thickening of the pericardium suggests tumor invasion. Areas of high signal represent hemorrhage.

(Left) Four-chamber view SSFP MR shows a large mass originating from the free wall of the right atrium. Note extension and involvement of the tricuspid valve and invasion through epicardial fat . These features are highly suggestive of angiosarcoma. (Right) Short-axis SSFP MR from the same patient shows a lobulated right atrial mass . Pathology showed this to be an angiosarcoma, the most common cardiac sarcoma subtype. P.6:31

TERMINOLOGY Definitions  Cardiac tumors that arise from 1 of the connective tissues (mesodermal cell origin) of the heart  As a group, they represent the most common type of primary cardiac malignancy  Restricted to heart and pericardium Types of Cardiac Sarcoma  Angiosarcoma, malignant fibrous histiocytoma, osteosarcoma, leiomyosarcoma, myxofibrosarcoma, synovial sarcoma, undifferentiated sarcomas IMAGING 477

Diagnostic Imaging Cardiovascular General Features  Best diagnostic clue o Invasive or infiltrative mass involving cardiac wall &/or chambers without known primary malignancy  Location o Angiosarcomas: Right atrium > left atrium o Other sarcomas (malignant fibrous histiocytoma [MFH], osteosarcoma, and leiomyosarcoma): Left atrium > right atrium o Mesothelioma: Visceral or parietal pericardium Radiographic Findings  Radiography o Chest radiography may be normal o Cardiomegaly is most common abnormality o Mass o Secondary findings due to obstructive physiology  Consolidation  Pericardial or pleural effusion  Congestive heart failure  Pulmonary venous hypertension (cephalization, Kerley lines, pulmonary edema)  Enlarged inferior vena cava (IVC) and superior vena cava (SVC) o Pulmonary metastases CT Findings  CECT o Discrete hypodense mass involving cardiac wall and chambers  Angiosarcoma is highly vascular  Ossification may occur in primary osteosarcoma o Diffuse infiltration o Pericardial invasion  Pericardial thickening and nodularity  Disruption of pericardium  Hemorrhagic pericardial effusion o Myocardial invasion  Invasion of interatrial septum in primary osteosarcoma o Mediastinal invasion o Pulmonary venous extension especially in leiomyosarcoma o Pulmonary metastases  Cardiac gated CTA o ± involvement of cardiac valve MR Findings  T1WI o Heterogeneous  Hypointense → necrosis  Intermediate → viable tumor  Hyperintense → hemorrhage or macroscopic fat (e.g., liposarcoma)  T2WI o Heterogeneously hyperintense  T1WI C+ o Heterogeneous enhancement  Marked surface enhancement and central necrosis o “Sunray” appearance  Lines of enhancement radiating from epicardium to pericardium  Denotes hemorrhage within tumor Ultrasonographic Findings  Echocardiogram o Compression and distortion of anatomy by irregular echogenic mass o Abnormal physiology depending on tumor location and extent o Transesophageal echocardiogram is useful in detection and guidance of transvenous biopsy Imaging Recommendations  Best imaging tool 478

Diagnostic Imaging Cardiovascular o Cardiac gated MR DIFFERENTIAL DIAGNOSIS Cardiac Metastasis  20-40x more common than primary sarcoma  Lung, breast, and esophageal cancers, melanoma Lymphoma  More common in immunocompromised patients  Right > left heart involvement Cardiac Myxoma  Endoluminal lesion without mural involvement  Well-circumscribed and usually in left atrium  Stalk connecting to interatrial septum Thrombus  Tumor is more likely to enhance  Acute thrombus may enhance  Characteristic locations (e.g., left atrial appendage and left ventricular apex following myocardial infarction)  No myocardial invasion Other Primary Benign Tumors  Rhabdomyoma, lipoma, hemangioma  No signs of invasion o Lipoma has capsule and follows fat signal intensity on all pulse sequences o Hemangioma may be part of Kasabach-Merritt syndrome (i.e., hemangioma thrombocytopenia syndrome: Multiple hemangioendotheliomas, thrombocytopenia, consumptive coagulopathy)  Demonstrates avid enhancement on CT and hyperintensity on T2 o Teratoma may have formed teeth, other calcification, or lipid/fluid level  Right-sided chambers > left  ± pericardial involvement P.6:32  Tissue from all 3 germ cell layers (including teeth, hair, fat, bone, epithelium, etc.) PATHOLOGY General Features  Sarcomas as a group are 2nd most common primary cardiac neoplasm after myxoma  Malignant tumor of mesenchymal cell origin  Variable appearance  Usually large heterogeneous invasive mass  May replace myocardial wall  Biopsies may be false negative due to tumor being covered with thrombus  Etiology: Unknown Staging, Grading, & Classification  Metastatic disease: 66-89% at presentation o Lungs > lymph nodes, bone, and liver Gross Pathologic & Surgical Features  Invasive mass or diffuse infiltration  May be hemorrhagic and multilobular  Cut surfaces typically firm and heterogeneous Microscopic Features  Microscopic features parallel the corresponding soft-tissue sarcoma o Angiosarcoma (37%): Most common histologic type o Undifferentiated (24%) o Malignant fibrous histiocytoma (11-24%) o Leiomyosarcoma (8-9%) o Osteosarcoma (3-9%) o Rhabdomyosarcoma  Most common cardiac sarcoma in pediatric population but may present at any age  No chamber predilection CLINICAL ISSUES 479

Diagnostic Imaging Cardiovascular Presentation  Most common signs/symptoms o Dyspnea or nonspecific signs/symptoms  Other signs/symptoms o Chest pain, arrhythmia, peripheral edema, tamponade, and sudden death o Peripheral tumor embolization  Clinical profile o Usually presents 3-6 months after onset of symptoms Demographics  Age o Mean age at presentation: 41 years o Extremely rare in infants and children  Most primary cardiac tumors in childhood are benign (90%)  Sarcomas make up 75-90% of all malignant cardiac tumors in children and 95% of all primary malignancies (5% are lymphomas)  Rhabdomyosarcoma is most common sarcoma in children  Gender o Angiosarcoma: M:F = 2:1 o Malignant fibrous histiocytoma: F > M Natural History & Prognosis  Poor prognosis; survival: 3 months to 4 years o Median survival = 6-12 months depending on whether there are metastases at presentation  Better prognosis o Left atrial involvement o Low mitotic rate o No necrosis o No metastases at diagnosis  Recurrence and metastases within 1 year Treatment  Surgery: Palliative; may prolong survival, especially in cases without metastatic disease  Palliative radiation and chemotherapy are often not very helpful  Selective heart transplantation DIAGNOSTIC CHECKLIST Consider  Primary cardiac sarcoma in patient with locally invasive mass involving cardiac wall and chambers  CT imaging of right atrial or ventricular tumors are difficult due to mixing artifact (contrast from SVC with unopacified blood from IVC) o Delayed imaging is useful to accurately delineate mass SELECTED REFERENCES 1. Look Hong NJ et al: Cardiac angiosarcoma management and outcomes: 20-year single-institution experience. Ann Surg Oncol. 19(8):2707-15, 2012 2. Bendel EC et al: Imaging sarcomas of the great vessels and heart. Semin Ultrasound CT MR. 32(5):377-404, 2011 3. Buckley O et al: Cardiac masses, part 2: key imaging features for diagnosis and surgical planning. AJR Am J Roentgenol. 197(5):W842-51, 2011 4. Hashimoto W et al: Primary cardiac osteosarcoma with imaging that revealed no calcification. Gen Thorac Cardiovasc Surg. 59(3):184-6, 2011 5. Randhawa K et al: Magnetic resonance imaging of cardiac tumors: part 2, malignant tumors and tumor-like conditions. Curr Probl Diagn Radiol. 40(4):169-79, 2011 6. Serdaroglu G et al: A rare cause of recurrent stroke in childhood: left atrial rhabdomyosarcoma. Acta Paediatr. 100(10):e189-91, 2011 7. Fresneau B et al: [Malignant primary cardiac tumors in childhood and adolescence.] Arch Pediatr. 17(5):495-501, 2010 8. O'Donnell DH et al: Cardiac tumors: optimal cardiac MR sequences and spectrum of imaging appearances. AJR Am J Roentgenol. 193(2):377-87, 2009 9. Murinello A et al: Cardiac angiosarcoma—a review. Rev Port Cardiol. 26(5):577-84, 2007 10. Sparrow PJ et al: MR imaging of cardiac tumors. Radiographics. 25(5):1255-76, 2005 11. Best AK et al: Best cases from the AFIP: cardiac angiosarcoma. Radiographics. 23 Spec No:S141-5, 2003 12. Chiles C et al: Metastatic involvement of the heart and pericardium: CT and MR imaging. Radiographics. 21(2):43949, 2001 480

Diagnostic Imaging Cardiovascular 13. Araoz PA et al: CT and MR imaging of benign primary cardiac neoplasms with echocardiographic correlation. Radiographics. 20(5):1303-19, 2000 14. Grebenc ML et al: Primary cardiac and pericardial neoplasms: radiologic-pathologic correlation. Radiographics. 20(4):1073-103; quiz 1110-1, 1112, 2000 P.6:33

Image Gallery

(Left) Coronal CECT shows an infiltrative mass involving the free wall of the right atrium. The round collection of contrast is a large right coronary artery aneurysm. (Right) Axial CECT from the same patient shows typical features of a malignant cardiac tumor. The mass is infiltrative and involves 2 cardiac chambers (right atrium and right ventricle ). Note large right coronary artery aneurysm .

(Left) Axial T1WI C+ FS MR from the same patient shows contrast enhancement within the mass and demonstrates enhancing pulmonary nodules consistent with metastases . The mass was a biopsy-proven angiosarcoma. (Right) LVOT SSFP MR shows a mass that is broadly adherent to the posterior-lateral left atrial wall and infiltrates the posterior mitral valve leaflet.

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(Left) Four-chamber view SSFP MR from the same patient shows an infiltrative mass involving the posterior wall of the left atrium with extension into the mitral valve. (Right) Four-chamber view T1WI C+ FS MR in the same patient demonstrates enhancement of the left atrial mass. This was a pathologically proven primary leiomyosarcoma in a 22-year-old woman. P.6:34

(Left) Composite image with axial T1WI MR with (right) and without (left) contrast of a patient with primary cardiac angiosarcoma shows a right atrial mass , isointense to muscle and with heterogeneous contrast enhancement . Note invasion through epicardial fat . (Right) Axial PET/CT of an angiosarcoma demonstrates FDG uptake within a right atrial mass . Angiosarcomas most commonly involve the right atrium; other primary cardiac sarcomas often have left atrial origin.

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(Left) T1-weighted post-contrast image with fat saturation shows diffuse enhancement of a sarcoma in the right atrioventricular groove. The right coronary artery is encased by the mass. (Right) Axial T1-weighted MR shows foci of hemorrhage in a large right atrial sarcoma. There is pericardial thickening extending anterior, posterior, and medial to the mass, a finding suggestive of tumor spread to the pericardium.

(Left) Vertical long-axis (2-chamber) SSFP MR shows a pedunculated mass in the left atrium. This is an atypical example of a metastatic alveolar soft parts sarcoma from the vulva in a 13-year-old girl. (Right) LVOT SSFP MR from the same patient shows a well-circumscribed mass in the left atrium. It was secondary to a metastatic alveolar soft parts sarcoma that had invaded the inferior left pulmonary vein and extended into the left atrium. P.6:35

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(Left) Axial CECT of a patient with cardiac sarcoma shows a predominantly hypodense mass arising from the right atrium. The disruption of epicardial fat and irregularity of adjacent pericardium are consistent with local invasion. (Right) Four-chamber view SSFP MR shows a large heterogeneous sarcoma arising from the lateral wall of the right atrium. It invades through the epicardial fat and abuts or invades the parietal pericardium.

(Left) Four-chamber view SSFP MR shows a large cardiac sarcoma centered around the right atrioventricular groove with invasion into the right atrium and right ventricle . The mass encases the right coronary artery . (Right) Four-chamber view MR perfusion from the same patient shows rapid early enhancement of the mass.

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Diagnostic Imaging Cardiovascular (Left) AP chest radiograph of a patient with primary cardiac angiosarcoma shows enlargement of the right atrium . Cardiomegaly is the most common abnormality detected on chest radiography in patients with cardiac sarcoma but is a nonspecific finding. (Right) Axial T1-weighted FSE MR shows a large infiltrative sarcoma in the right atrium. The hyperintense signal represents tumoral hemorrhage. Note invasion into the distal aspect of the superior vena cava .

Tumor Mimics Tumor Mimics Kathryn M. Olsen, MD John D. Grizzard, MD Key Facts Terminology  Pseudomasses: Entities that appear as masses on initial imaging (usually echo) but often are either normal structures or clinically insignificant variant lesions; usually resolved with cross-sectional imaging (CT or MR) Imaging  Crista terminalis: Normal structure denoting site of embryologic fusion of primitive right atrium (RA) with sinus venosus o Usually recognized on cine MR as part of RA wall o Often best appreciated on 4-chamber or axial view  Eustachian valve: Variably prominent but normal ridge of tissue at junction of inferior vena cava (IVC) with RA o Recognized by characteristic location at junction of IVC with RA  Lipomatous hypertrophy of interatrial septum: Infiltration of interatrial septum by fatty hyperplasia o Recognized by characteristic fat signal and specific location o Typically spares fossa ovalis  Thrombus: Not actually a mimic but truly a mass, yet not a neoplasm o Often adheres to sites of prior ventricular infarction o Uniformly low in signal on delayed-enhancement MR images with long inversion time (600 milliseconds)  Mitral annular calcification (particularly tumefactive variant) o CT: Calcific density in characteristic location o MR: Low signal on all sequences  Less common mimics: Sinus of Valsalva aneurysms, aneurysms of membranous septum adjacent to ventricular septal defects

(Left) Short-axis MR cine shows prominent Eustachian valve at RA-IVC junction, which may have a mass-like appearance on echocardiography or simulate thrombus. (Right) LGE MR (bottom) and 4-chamber view cine MR (top) show thrombus in the LV apex. Note that the thrombus is isointense on cine MR and dark on LGE MR with a long inversion time (600 milliseconds) . The patient has an apical myocardial infarction, which was better seen on LGE MR images with a standard inversion time.

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(Left) Two sequential 4-chamber view MR cine images demonstrate a prominent crista terminalis along the margin of the RA. Note its polypoid appearance and characteristic location at the intersection of the right atrial appendage with the SVC-RA junction. Also, it is isointense to the myocardium on these cine images and on all sequences obtained. (Right) Vertical long-axis (2-chamber) MR cine in the plane of the crista terminalis (same patient) shows its vertical extent and characteristic location. P.6:37

TERMINOLOGY Synonyms  Pseudomasses Definitions  Entities that appear to represent masses on initial imaging (usually echo) but often are either normal structures or clinically insignificant variant lesions; usually resolved with cross-sectional imaging (CT or MR) o Common pseudomasses  Crista terminalis  Normal anatomic structure indenting right atrium (RA)  Demarcates site of fusion of embryologic RA with sinus venosus  When prominent, can be mistaken for mass on echo  True nature easily clarified with MR or CT  Eustachian valve  Variably prominent ridge of tissue at junction of inferior vena cava (IVC) with RA  Directs blood flow toward foramen ovale in fetal life  When prominent, can be mistaken for mass on echo  True nature easily clarified with MR or CT  Lipomatous hypertrophy of interatrial septum (LHIAS)  Not a neoplasm  Hyperplasia of normal fat cells often contiguous with epicardial fat  Fat infiltrates interatrial septum and expands it to diameter > 2 cm but spares fossa ovalis, creating dumbbell shape  May be hot on PET due to composition of brown fat, which is FDG avid  Thrombus  Actually a mass, not a pseudomass, but not a neoplasm  Mitral annular calcification (MAC)  Calcification of fibrous annulus of mitral valve usually occurring as degenerative change  Occurs earlier and is more extensive in renal failure  May appear mass-like in some cases, especially if caseous MAC  Sinus of Valsalva aneurysm  Abnormal enlargement of single sinus, usually the right (˜ 80%)  Usually congenital in origin, less commonly due to endocarditis 486

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Membranous septal aneurysm associated with ventricular septal defect (VSD)  Redundant septal tissue arising adjacent to membranous VSD that may appear mass-like  May partially occlude VSD Miscellaneous lesions: Less common causes of confusion on imaging  Hiatal hernia  Complex/loculated pericardial effusion or prominent pericardial fat

IMAGING General Features  Best diagnostic clue o Some of these lesions are incidentally detected in otherwise normal individuals  Often, CT or MR imaging requested because of confusing echocardiographic findings  Location o Variable, but most commonly in RA or extrinsic to heart  Size o Variable, depending on true nature of lesion or normal structure  Morphology o Variable, depending on true nature of lesion MR Findings  Crista terminalis usually recognized on cine MR images as being part of RA wall o Often best appreciated on 4 chamber or axial view o Cine imaging in oblique sagittal long-axis plane also helpful to demonstrate its vertical orientation along margin of RA o Has same signal characteristics as RA wall on cine, T1, T2, and late gadolinium enhancement (LGE) MR  Eustachian valve recognized by characteristic location at junction of IVC with RA o May have “comma” shape with concavity toward fossa ovalis o Signal characteristics same as myocardium on all sequences  LHIAS recognized by characteristic fat signal and specific location o Bright on T1 and T2 with signal dropout on fat-suppressed images o Does not enhance o Fat may occasionally extend superiorly along RA wall for variable distance  Thrombus o Recognized by characteristic intracavitary location  Found in left atrium (LA) or atrial appendage in cases of atrial fibrillation or atrial stasis from restrictive cardiomyopathy, particularly amyloid  Found in left ventricle (LV) adjacent to infarcts/aneurysms  May be seen in right atrium (RA) secondary to central lines o May be mobile with adherent stalk (mimicking myxomas) o Isointense to muscle on cine MR imaging  Differentiates from myxomas, which are higher in signal intensity than muscle on cine MR o No contrast uptake on perfusion MR o Low signal on LGE MR with long inversion time (600 milliseconds)  Mitral annular calcification o Low in signal on all imaging sequences o Does not enhance o “Caseous necrosis” variant may have high signal on T1 sequences o Often predominantly involves posterior leaflet, but entire annulus is involved in more severe cases  Miscellaneous/uncommon lesions o Sinus of Valsalva aneurysm P.6:38   

o

May contain signal and hence appear solid on black-blood MR due to slow flow May protrude into RV/RVOT Occasionally complicated by rupture, usually into RV (90%) or RA, resulting in left-to-right shunt Membranous septal aneurysm associated with VSD  Redundant membranous tissue often demonstrates mobility on cine MR 487

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o o

 May have “windsock” appearance with flow jet visible on cine MR  May prolapse through membranous VSD into RV or RVOT Hiatal hernia easily recognized on MR as intrathoracic stomach  Often indents posterior wall of LA Pericardial fat or complex fluid  Signal characteristics and appearance on cine MR usually definitive  Occasionally, fat-suppressed turbo spin echo T1 or T2 images helpful  Fat along atrioventricular groove adjacent to RA occasionally mistaken for mass

CT Findings  Findings often similar to MR findings, but soft tissue contrast is inferior o Crista terminalis location and morphology as per MR o Eustachian valve location and morphology as per MR o LHIAS often easily seen on NECT and CECT and recognized as low attenuation infiltration of interatrial septum o Mitral annular calcification  Calcific density easily visualized on CT  Often predominantly involves posterior leaflet, but entire annulus is involved in more severe cases  Rarely undergoes “caseous necrosis” and may then have lower central density with calcific rim o Miscellaneous/uncommon lesions  Hiatal hernia easily recognized on CT ± oral contrast  Pericardial fat or complex fluid also easily resolved with CT  Sinus of Valsalva aneurysm detectable on gated CT  Visualization of membranous septal aneurysms requires  Gated CT with differential LV/RV contrast  Careful contrast bolus shaping/timing Imaging Recommendations  Best imaging tool o MR or CT usually resolve diagnosis; MR often preferred due to superior soft-tissue contrast resolution DIFFERENTIAL DIAGNOSIS Varies With Lesion Type  Crista terminalis may mimic true mass in RA wall, such as angiosarcoma or metastasis o Recognized as part of wall with no invasive features  Eustachian valve may mimic IVC extension of intraabdominal tumor, such as renal, adrenal, or hepatocellular carcinoma o Recognized as part of RA-IVC junction and not true intraluminal mass  LHIAS may mimic true neoplasm of fat cells (lipoma) o Recognized by characteristic location and sparing of fossa ovalis  Thrombus may mimic other intracavitary masses, such as myxoma o Cine MR: Thrombus is isointense to myocardium; myxomas usually hyperintense due to their gelatinous composition o LGE MR: Thrombi uniformly low in signal on images with long inversion time (600 milliseconds); myxomas will often have enhancing stalk  Mitral annular calcification o True nature usually evident on CT or MR PATHOLOGY Staging, Grading, & Classification  Varies with lesion type  Many of these entities are normal variants CLINICAL ISSUES Presentation  Most common signs/symptoms o Usually none; patients present for MR or CT imaging to resolve confusing echocardiographic studies o Thrombi usually in setting of atrial fibrillation, cardiomyopathy, or post myocardial infarction DIAGNOSTIC CHECKLIST Consider  Referrals from echocardiography for RA mass may actually represent pseudomass 488

Diagnostic Imaging Cardiovascular  Comprehensive imaging with MR is usually best technique to determine true nature of cardiac mass Image Interpretation Pearls  Cine MR imaging very useful to localize cardiac mass as intramural, epicardial, or intracavitary, significantly narrowing the differential diagnostic possibilities  LGE MR often very useful in tissue characterization of true cardiac masses and in excluding pseudomasses  Perfusion imaging with MR very helpful to determine presence or absence of contrast uptake and vascularity of suspected cardiac mass SELECTED REFERENCES 1. Anavekar NS et al: Computed tomography of cardiac pseudotumors and neoplasms. Radiol Clin North Am. 48(4):799-816, 2010 2. Weinsaft JW et al: Detection of left ventricular thrombus by delayed-enhancement cardiovascular magnetic resonance prevalence and markers in patients with systolic dysfunction. J Am Coll Cardiol. 52(2):148-57, 2008 3. Salanitri JC et al: Cardiac lipoma and lipomatous hypertrophy of the interatrial septum: cardiac magnetic resonance imaging findings. J Comput Assist Tomogr. 28(6):852-6, 2004 4. Meier RA et al: MRI of right atrial pseudomass: is it really a diagnostic problem? J Comput Assist Tomogr. 18(3):398401, 1994 5. Mirowitz SA et al: Fibromuscular elements of the right atrium: pseudomass at MR imaging. Radiology. 182(1):231-3, 1992 P.6:39

Image Gallery

(Left) Four-chamber view cine SSFP image demonstrates fat in the interatrial septum . Note the sparing of the fossa ovalis . This results in a “dumbbell” appearance that is characteristic of this lesion. (Right) Axial NECT at the level of the fossa ovalis shows low-attenuation fat infiltrating the interatrial septum in a case of lipomatous hypertrophy of the interatrial septum (LHIAS). It is often observed that the interatrial fat is contiguous with epicardial fat on other slices.

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(Left) Four-chamber (top) and SAX (bottom) cine MR images show bulky mitral annular calcification in the posterior leaflet of the mitral valve. Pre-contrast images (left) and post-contrast images (right) show no enhancement and uniform low signal. (Right) Modified 4-chamber cine MR views show membranous septum aneurysm prolapsing from LV to RV through the associated membranous VSD. Turbulent transseptal flow results in perilesional flow artifacts noted in the systolic image (right).

(Left) Cine MR image in the plane of the aortic valve shows an aneurysm of the right sinus of Valsalva . The right sinus is most often involved in a congenital sinus of Valsalva aneurysm. (Right) Modified coronal views through the aortic valve in the same patient show the aneurysm of the right sinus of Valsalva bulging into the RA (left image) and the significant complication of rupture into the RV (right image). Note the turbulent flow through the defect .

Hemangioma Hemangioma John D. Grizzard, MD Key Facts Terminology  Benign tumor composed of vascular endothelial cells Imaging  Hypervascular mass without aggressive features  Approximately 75% are intramural, 15% endocardial/intracavitary, and 10% epicardial/pericardial  Can occur in any chamber or wall  MR provides most comprehensive assessment  CT shows intensely enhancing heterogeneous mass 490

Diagnostic Imaging Cardiovascular Top Differential Diagnoses  Location dependent o Intracavitary: Myxoma o Intramural: Metastases (adults); rhabdomyoma/fibroma (children) o Epicardial: Metastases (adults); teratoma/lymphangioma (children) Clinical Issues  Rare tumors estimated to make up 5-10% of all primary cardiac masses  Surgery usually recommended if diagnosis is uncertain or if lesion is symptomatic  Treatment is surgical excision o Sometimes complete surgical excision is not possible due to intramural location, but recurrence is uncommon  Many are asymptomatic, incidental findings detected on imaging for unrelated finding, such as murmur  When symptomatic, dyspnea on exertion and arrhythmias are most common manifestations  Rarely may be seen in Kasabach-Merritt syndrome with recurrent thrombocytopenia and coagulopathy associated with multiple systemic hemangiomas

(Left) Axial CECT demonstrates a large epicardial hemangioma seen as an enhancing mass with internal septations. Note that the mass is inseparable from the posterior margin of the left ventricle. (Right) Axial oblique T1WI FSE MR of the same hemangioma shows that the lesion is minimally hyperintense to the myocardium. Again, note that the lesion appears to involve the posterior epicardial surface of the left ventricle.

(Left) Axial T2WI FSE MR of this complex mass shows that it is high in signal intensity on T2-weighted imaging. Note that the internal septations on this sequence appear relatively low in signal intensity. (Right) Axial FSE STIR MR shows very bright signal, classic for hemangioma on STIR imaging. Note the internal septations . Note also that the STIR 491

Diagnostic Imaging Cardiovascular sequence, as performed, results in excellent fat-suppression, but the lesion remains markedly hyperintense. P.6:41

TERMINOLOGY Synonyms  Angioma Definitions  Benign tumor composed of vascular endothelial cells IMAGING General Features  Best diagnostic clue o Hypervascular mass without aggressive features  Location o Approximately 75% are intramural, 15% endocardial/intracavitary, and 10% epicardial/pericardial o Can occur in any chamber or wall  Atria slightly more common than ventricles in childhood, and right atrium > left atrium  Ventricles or interventricular septum slightly more common in adults series  Size o Variable, ranging from small (˜ 5-10 mm) polypoid intracavitary lesion to large intramural or epicardial mass (> 10 cm)  Morphology o When intracavitary, may be rounded or polypoid in appearance with short stalk similar to myxoma o When mural or epicardial, often amorphous and may mold to adjacent structures Radiographic Findings  Radiography o May show enlargement of cardiac silhouette when large CT Findings  NECT o Heterogeneous mass that may be intramural or epicardial  CECT o Intense enhancement post contrast  Small endocavitary lesions may require careful contrast bolus timing to be best demonstrated MR Findings  T1WI o Isointense to mildly hyperintense  T2WI o Hyperintense  STIR o Markedly hyperintense  T1WI C+ o Clear enhancement usually evident; central core may scar or thrombose and have diminished uptake relative to periphery  Late gadolinium enhancement (LGE) o Heterogeneous with areas that null similarly to normal myocardium as well as hyperenhanced areas  1st-pass perfusion imaging o Isointense to strongly hyperintense Ultrasonographic Findings  Grayscale ultrasound o Typically hyperechoic at echocardiography Imaging Recommendations  Best imaging tool o Multisequence multiplanar MR provides the most comprehensive assessment  Protocol advice o 1st-pass perfusion imaging very helpful in demonstrating hypervascular nature of mass o Cine MR important to assess borders of lesion to determine degree of infiltration and likelihood of complete resection 492

Diagnostic Imaging Cardiovascular DIFFERENTIAL DIAGNOSIS Depends on Location  Intracavitary lesions o Myxoma  Usually has attachment to fossa ovalis, which is uncommon with hemangioma  1st-pass perfusion MR imaging usually shows minimal enhancement or enhancement of stalk only  Intramural lesions o Childhood  Rhabdomyoma  Most often seen in patients with tuberous sclerosis  Isointense to myocardium on all sequences, particularly LGE MR and 1st-pass perfusion imaging  Fibroma  Bright on LGE MR; may have dark center, particularly if imaged early, similar to hemangioma  Usually hypointense on T2WI, not markedly hyperintense as hemangioma  Hypointense on 1st-pass perfusion imaging o Adulthood  Metastases  20-40x more common than primary tumors  Most often have infiltrating, poorly marginated appearance  Enhancement on LGE MR heterogeneous, similar to hemangioma  Hypervascular metastases (renal cell, melanoma, etc.) may have prominent 1stpass perfusion uptake  Usually seen in patients with advanced known malignancy  Typically more aggressive in appearance than hemangioma with higher incidence of pericardial effusion  Primary cardiac sarcomas  Rare tumors; most common is angiosarcoma, which has predilection for right atrium involvement, similar to hemangioma  May be hypervascular on 1st-pass perfusion imaging  Heterogeneous uptake on LGE MR, similar to hemangioma  Typically more aggressive in appearance than hemangioma, with higher incidence of pericardial effusion  Paraganglioma P.6:42    

Signal intensity similar to hemangioma (isointense to mildly hyperintense on T1WI, very bright on T2WI) Markedly hypervascular on perfusion imaging, similar to hemangioma Heterogeneous on LGE MR, similar to hemangioma Typically present with symptoms of catecholamine excess

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Epicardial o Childhood  Teratomas  Complex but usually circumscribed tumors  Usually do not show hypervascular appearance on perfusion imaging  Lymphangiomas  Tumors of dilated lymphatic channels that do not communicate with lymphatic tree  Usually contained within pericardial sac, without myocardial extension  Minimal or no significant contrast uptake o Adulthood  Metastases  Most common cause of epicardial/pericardial neoplastic disease  Pericardial effusions extremely common and may be cause of clinical presentation PATHOLOGY 493

Diagnostic Imaging Cardiovascular General Features  Associated abnormalities o Rarely, hemangiomas of gastrointestinal tract Gross Pathologic & Surgical Features  May be clearly demarcated, lobular tumor or have infiltrating margins, resulting in difficulty in resection Microscopic Features  May be cavernous, capillary, or arteriovenous in type  Cavernous type is similar to cavernous hemangiomas elsewhere o Usually intramural in location  Capillary types composed of lobules of endothelial cells o Often (50%) endocardial and project intraluminally  Arteriovenous malformation type lesions have areas of dysplastic, thickened arterial and venous structures similar to arteriovenous malformations elsewhere o Make up 50% of cardiac hemangiomas o Most often are intramural in location CLINICAL ISSUES Presentation  Most common signs/symptoms o Many are asymptomatic, incidental findings detected on imaging for unrelated finding, such as murmur o When symptomatic, dyspnea on exertion and arrhythmias are most common manifestations o Rarely may be seen in Kasabach-Merritt syndrome with recurrent thrombocytopenia and coagulopathy associated with multiple systemic hemangiomas  Other signs/symptoms o Uncommonly, pericardial effusions or congestive heart failure may develop  Rarely, may present with syncope or sudden death Demographics  Age o All ages reported, from infancy to old age, with median age of 43 years  Gender o Males predominate in most reported series  Epidemiology o Rare tumors estimated to make up 5-10% of all primary cardiac masses Natural History & Prognosis  Most remain asymptomatic, and spontaneous regression has been occasionally reported  Surgery usually recommended if diagnosis is uncertain or if lesion is symptomatic Treatment  Surgical excision; sometimes complete surgical excision is not possible due to intramural location, but recurrence is uncommon DIAGNOSTIC CHECKLIST Consider  Hemangioma should be in differential diagnosis for hypervascular intramural lesions lacking other aggressive features o Particularly in patients without known malignancy Image Interpretation Pearls  Perfusion imaging often confirms nature as hypervascular lesion o Note that some large hemangiomas may show delayed or absent filling of center of lesion  However, lesions have benign, circumscribed appearance and are not infiltrative as are most malignancies SELECTED REFERENCES 1. Beroukhim RS et al: Characterization of cardiac tumors in children by cardiovascular magnetic resonance imaging: a multicenter experience. J Am Coll Cardiol. 58(10):1044-54, 2011 2. Shroff GS et al: Giant pericardial lymphangioma—imaging, surgical, and pathologic correlations. J Comput Assist Tomogr. 35(5):642-4, 2011 3. Tomasian A et al: Cardiac hemangioma: features on cardiovascular magnetic resonance. J Cardiovasc Magn Reson. 9(6):873-6, 2007 4. Alsaileek A et al: Diagnostic features of cardiac hemangioma on cardiovascular magnetic resonance, a case report. Int J Cardiovasc Imaging. 22(5):699-702, 2006

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Image Gallery

(Left) Sagittal SSFP cine image shows a complex epicardial mass along the posterior cardiac margin . Note the incidental large left renal cyst . The SSFP sequence results in a modified T2 weighting. The complex cystic and solid nature of the lesion is well seen on cine imaging. (Right) Sagittal STIR image shows a very high signal intensity mass with internal septations, consistent with hemangioma. Note again that the mass appears inseparable from the posterior left ventricle margin.

(Left) Perfusion MR image shows enhancement along posterior periphery of lesion . The center filled in significantly later. Many large cavernous hemangiomas will show this pattern of peripheral early enhancement with delayed or absent central enhancement, often indicative of a large central scar. (Right) Late gadolinium enhancement (LGE) MR shows a heterogeneous enhancement pattern . Areas of intermixed low and high signal reflect the areas of contrast enhancement with nonenhancing septations.

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(Left) SAX (top row) and 2-chamber (bottom row) views show renal carcinoma metastases. Cine images (left) show a mass effect due to metastases . Perfusion images (middle) show that the lesions are hypervascular. LGE MR images (right) show heterogeneous enhancement. (Right) Axial views (top row) show paraganglioma of the atrial septum that is minimally hyperintense on T1WI (left), and bright on T2WI (right). Note the high signal on STIR and hypervascular appearance on MRA .

Papillary Fibroelastoma Papillary Fibroelastoma Suhny Abbara, MD, FSCCT Key Facts Terminology  Benign endocardial papilloma that predominantly affects cardiac valves Imaging  Pedunculated, valvular/paravalvular mass  Most arise from heart valves o Aortic valve (29%) o Mitral valve (25%) o Pulmonary valve (13%) o Tricuspid valve (17%)  Typically on aortic side of aortic valve  Typically on atrial side of mitral valve  Round, oval, or irregular in shape o Connected via thin stalk o Arises from body of valves o Unlike vegetations that tend to be near coaptation margin of valve Top Differential Diagnoses  Thrombus o May be indistinguishable from fibroelastoma  Vegetations o Often at leaflet tips Pathology  Gelatinous mass with characteristic “sea anemone” appearance; fronds are best seen by immersing tumor in water Clinical Issues  Patients may become symptomatic if tumor fragments or thrombus on surface of tumors result in embolic event  Patients are generally asymptomatic  Transient ischemic attacks or stroke from cerebrovascular occlusion  Myocardial infarction from coronary artery occlusion 496

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(Left) Three-chamber view graphic shows a small mass with a thin stalk and multiple frond-like projections arising from the aortic side of the aortic valve. Note the normal thickening of the cusps at the central coaptation site (nodules of Arantius). (Right) Axial cardiac CT shows a small rounded mass with microlobulated surface arising from the aortic side of the aortic valve. It is connected via a thin stalk to the right coronary cusp. These findings are characteristic for papillary fibroelastoma.

(Left) Aortic root short-axis fat-saturated FSE image demonstrates a small rounded mass arising from the left coronary cusp. Note that the mass is not near the center of the valve. (Right) Three-chamber view GRE MR shows a small rounded mass arising from the atrial side of the mid anterior mitral leaflet, a common location for mitral papillary fibroelastoma. Note that, unlike vegetation, the mass is not at the tip of leaflets. P.6:45

TERMINOLOGY Definitions  Benign endocardial papilloma that predominantly affects cardiac valves IMAGING General Features  Best diagnostic clue o Pedunculated, valvular/paravalvular mass o Low signal intensity on T2-weighted images due to high fibrous content of lesion  Location o Tends to arise from heart valves in 90% of cases  Aortic valve (29%), mitral valve (25%), pulmonary valve (13%), tricuspid valve (17%) 497

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Typically on aortic side of aortic valve and on atrial side of mitral valve

Size

o Range: 2-28 mm (median: 8 mm); 99% of all tumors measure < 20 mm  Morphology o Round, oval, or irregular in shape o “Speckled” appearance or “stippling” around tumor perimeter has also been described Imaging Recommendations  Best imaging tool o Echocardiography has been the primary imaging modality in years past although MR is rapidly becoming gold standard for evaluation of cardiac masses  Protocol advice o Lesions are best detected on bright blood SSFP sequences on MR due to their inherent low signal; tumors tend to be obscured by blood pool on conventional spin-echo black blood images DIFFERENTIAL DIAGNOSIS Thrombus  May be indistinguishable from fibroelastoma  Results in higher incidence of valvular dysfunction than fibroelastoma Atrial Myxoma  Typically arises from interatrial septum  Generally larger than fibroelastoma Vegetation  Often at leaflet tips  May be mobile  Not typically attached with a stalk Aortic Valve Rheumatoid Nodules  Complication of rheumatoid arthritis  Nodules represents granulomas Nodules of Arantius  Normal structure at coaptation center of aortic cusps  May rarely hypertrophy and mimic vegetations or masses PATHOLOGY General Features  Associated abnormalities o Rheumatic valvulitis, valvular fibrosis, &/or calcification o Hypertropic cardiomyopathy o Aortic aneurysm o Congenital heart disease Gross Pathologic & Surgical Features  Gelatinous mass with characteristic “sea anemone” appearance o Fronds are best seen by immersing the tumor in water CLINICAL ISSUES Presentation  Most common signs/symptoms o Patients are generally asymptomatic  Most lesions are incidentally discovered at autopsy or while undergoing coronary surgery, echocardiography, or cardiac catheterization  Other signs/symptoms o Patients may become symptomatic if tumor fragments or thrombus on surface of tumors results in embolic event  Transient ischemic attacks or stroke from cerebrovascular occlusion  Dyspnea from pulmonary emboli  Myocardial infarction from coronary artery occlusion o May rarely prolapse into coronary ostia Demographics  Age o Mean: 60 years  Epidemiology o 2nd most common benign primary cardiac neoplasm 498

Diagnostic Imaging Cardiovascular o Accounts for ˜ 75% of all cardiac valvular tumors Natural History & Prognosis  Patients are generally asymptomatic with little incidence of valvular dysfunction; in setting of thromboembolic events, lesions can be surgically excised with virtually no reported recurrence Treatment  Simple surgical excision with possible leaflet repair or valve replacement SELECTED REFERENCES 1. Val-Bernal JF et al: Cardiac papillary fibroelastoma: Retrospective clinicopathologic study of 17 tumors with resection at a single institution and literature review. Pathol Res Pract. 209(4):208-14, 2013 2. Bouhzam N et al: Incidental papillary fibroelastoma multimodal: imaging and surgical decisions in 2 patients. Tex Heart Inst J. 39(5):731-5, 2012 3. Sun JP et al: Clinical and echocardiographic characteristics of papillary fibroelastomas: a retrospective and prospective study in 162 patients. Circulation. 103(22):2687-93, 2001 4. Edwards FH et al: Primary cardiac valve tumors. Ann Thorac Surg. 52(5):1127-31, 1991

Fibroma Key Facts Terminology  Fibrous hamartoma, fibroelastic hamartoma  Benign congenital cardiac neoplasm composed of fibroblasts and abundant collagen Imaging  Solitary myocardial mass most evident as area of altered contraction on cine imaging  Most commonly arises in left ventricular free wall, interventricular septum, or right ventricular free wall  Most often solid, well-defined mass o Less commonly has infiltrative appearance  Calcifications seen in 15-20% on CT  Isointense ventricular wall mass that does not show contraction on cine MR imaging  Hypointense on T2WI in adults, particularly centrally o T2 hypointensity is very uncommon in any other cardiac tumor and strongly suggests fibroma when seen  LGE MR shows intense hyperenhancement  MR perfusion imaging can help differentiate from aggressive lesions as fibromas do not show enhancement on 1st-pass perfusion imaging Top Differential Diagnoses  Rhabdomyoma  Hemangioma  Hypertrophic cardiomyopathy  Metastases  Rhabdomyosarcoma  Myxoma  Paraganglioma Clinical Issues  85% children, 15% adolescents and adults  Surgical excision is treatment of choice  Recurrence is uncommon even after incomplete resection

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(Left) Axial graphic shows a fibroma compressing both ventricles. Note its intramural location within the right ventricular (RV) free wall. Also note that it is a solitary lesion involving the ventricle. These findings are typical of fibroma. (Right) Frontal radiograph shows a mass along the superior left heart border . The most common finding of fibroma (if any) on plain radiography is the presence of a focal contour deformity. Calcification, commonly noted on CT, is less commonly visualized on radiographs.

(Left) Three-chamber image from a gated cardiac CT shows a large soft-tissue mass within the left ventricular myocardium . The mass is isodense to normal myocardium. Note the characteristic calcification . Note also that the lesion is solitary and appears well defined, with no associated pericardial effusion. (Right) Short-axis image from a gated cardiac CT shows a large isodense mass within the left ventricular (LV) free wall . Note the intramural location of the mass and the central calcification . P.6:47

TERMINOLOGY Synonyms  Fibrous hamartoma  Fibroelastic hamartoma Definitions  Benign congenital cardiac neoplasm composed of fibroblasts and abundant collagen IMAGING General Features  Best diagnostic clue o Solitary myocardial mass most evident as area of altered contraction on cine imaging 500

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Location o Most commonly arises in left ventricular free wall, interventricular septum, or right ventricular free wall (in declining order)  Rare in atria  Size o Diameter range: Typically 2-7 cm with mean of 5 cm in 1 pathology series  Morphology o Most often solid, well-defined mass  Less commonly has infiltrative appearance  Coarse calcifications seen in 15-20% on CT Radiographic Findings  Radiography o Cardiomegaly or focal bulge o Calcifications sometimes noted but less often than with CT CT Findings  NECT o Homogeneous mass, can have calcification  Solitary ventricular mass arising from myocardium with calcification strongly suggests diagnosis  CECT o Heterogeneous enhancement MR Findings  T1WI o Isointense to myocardium  T2WI o Often hypointense in adults, particularly centrally  T2 hypointensity is very uncommon in any other cardiac tumor and strongly suggests fibroma when seen  May be mildly T2 hyperintense in infants and children due to relatively greater cellularity  SSFP white blood cine o Isointense ventricular wall mass that does not show contraction or deformity with contraction  Late gadolinium enhancement (LGE) o Shows intense delayed hyperenhancement o Sometimes may have nonenhancing central core  1st-pass perfusion imaging o Fibromas do not show enhancement on first-pass perfusion imaging Echocardiographic Findings  Echocardiogram o Large, solid, noncontractile mass in myocardium  Calcification can be seen  May mimic focal hypertrophic cardiomyopathy Imaging Recommendations  Best imaging tool o Echocardiography is most often used for detection o MR is superior at characterization  MR showing T2 hypointense intramural ventricular mass with intense enhancement on LGE MR is virtually diagnostic of fibroma o CT demonstrating intramural ventricular noncontractile mass containing calcification is also strongly suggestive of fibroma  Protocol advice o LGE MR is very useful in differentiating from rhabdomyoma o 1st-pass perfusion imaging is useful in differentiating from tumors that are more aggressive (e.g., metastases) or vascular (e.g., hemangiomas) DIFFERENTIAL DIAGNOSIS Rhabdomyoma  Ventricular mass in young patients o 50% have tuberous sclerosis o Often multiple (whereas fibroma is solitary lesion) 501

Diagnostic Imaging Cardiovascular o Does not calcify LGE MR shows signal intensity identical to normal myocardium (nulls or becomes dark) as opposed to intense enhancement of fibroma  Often regresses spontaneously Metastatic Disease  Typically presents with multiple, multifocal masses in patients with known primary malignancy o Multiplicity differentiates from fibroma, which is solitary lesion  Most often isointense on T1, mildly hyperintense on T2, heterogeneous on LGE MR  Often hypervascular on MR perfusion imaging (whereas fibroma is hypovascular)  May be located anywhere whereas fibroma is intramural and ventricular in origin Hemangioma  When presenting as intramural mass, may simulate fibroma on cine MR imaging and CT o High signal on T2-weighted imaging  Fibroma is classically hypointense on T2 imaging in older children and adults o Usually hypervascular on perfusion imaging (whereas fibroma is hypovascular) o Enhances intensely on LGE MR Rhabdomyosarcoma  Most common primary cardiac malignancy in childhood  Large, heterogeneous, invasive mass that can occur anywhere in heart  Shows poor boundary definition and infiltration on imaging Hypertrophic Cardiomyopathy  Asymmetric septal variant can mimic focal mass o Some contraction may be evident on cine imaging P.6:48 

o o

Isointense on T2 imaging (whereas fibroma is hypointense) LGE MR imaging shows characteristic right ventricular insertion site hyperenhancement in majority of patients No calcification

o Myxoma  Intracavitary gelatinous neoplasm (whereas fibroma is intramural)  75% are left atrial o Most others are right atrial or biatrial o < 3% arise in ventricles (whereas fibroma is usually ventricular in location) Paraganglioma  Patients often present with signs of catecholamine excess  Epicardial/intramural tumor at roof of left atrium or interatrial septum (whereas fibroma is rare in atria) o Very hyperintense on T2-weighted imaging and hypervascular on perfusion imaging o May have calcification, similar to fibroma PATHOLOGY General Features  Etiology o May be hamartoma rather than neoplasm  Genetics o When presenting as isolated abnormality, no defined genetic defect  Associated abnormalities o Gorlin syndrome  Premalignant condition with multisystem involvement  Also known as basal cell nevus syndrome  ˜ 3% of patients have fibromas Gross Pathologic & Surgical Features  Large, firm, white, fibrous masses within ventricular myocardium with discrete or (less commonly) infiltrative margins o 25% calcify o No necrosis, hemorrhage, or cystic change Microscopic Features  Infants 502

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Fibroblast rich tumor with little collagen  May explain higher T2 signal that is often noted in infants and children  Adolescents and adults o Predominantly collagenous  Abundance of collagen results in characteristic low signal on T2 MR imaging  Also likely explains marked hyperenhancement seen on LGE MR imaging  Occasional mitoses, elastic tissue CLINICAL ISSUES Presentation  Most common signs/symptoms o 1/3 of patients are asymptomatic, and lesion is discovered incidentally o 1/3 present with heart failure or cyanosis o 1/3 present with arrhythmias or syncope  2nd most common tumor associated with sudden death after atrioventricular node heterotopias  Other signs/symptoms o Lesions may result in murmurs due to disturbed flow Demographics  Age o 85% children, 15% adolescents and adults o 1/3 are < 1 year of age at diagnosis  Gender o No gender predilection  Epidemiology o ˜ 100 reported cases in 30 years Natural History & Prognosis  Can interfere with mechanical or electrical function  Can be dormant; may regress Treatment  Surgical excision is treatment of choice o Resection may necessarily be incomplete if tumor extensively involves ventricular wall o Recurrence uncommon even after incomplete resection  Controversial conservative approach if asymptomatic DIAGNOSTIC CHECKLIST Consider  Fibroma in cases of solitary ventricular cardiac mass in child or adolescent Image Interpretation Pearls  Solitary ventricular mass o Dark on T2 o Bright on LGE MR o Shows calcifications on CT Reporting Tips  Extent of ventricular myocardial involvement to determine resectability and reconstruction needed SELECTED REFERENCES 1. Beroukhim RS et al: Characterization of cardiac tumors in children by cardiovascular magnetic resonance imaging: a multicenter experience. J Am Coll Cardiol. 58(10):1044-54, 2011 2. Burke A et al: Pediatric heart tumors. Cardiovasc Pathol. 17(4):193-8, 2008 3. Araoz PA et al: CT and MR imaging of benign primary cardiac neoplasms with echocardiographic correlation. Radiographics. 20(5):1303-19, 2000 4. Becker AE: Primary heart tumors in the pediatric age group: a review of salient pathologic features relevant for clinicians. Pediatr Cardiol. 21(4):317-23, 2000 5. Grebenc ML et al: Primary cardiac and pericardial neoplasms: radiologic-pathologic correlation. Radiographics. 20(4):1073-103; quiz 1110-1, 1112, 2000 6. Burke AP et al: Cardiac fibroma: clinicopathologic correlates and surgical treatment. J Thorac Cardiovasc Surg. 108(5):862-70, 1994 7. Parmley LF et al: The clinical spectrum of cardiac fibroma with diagnostic and surgical considerations: noninvasive imaging enhances management. Ann Thorac Surg. 45(4):455-65, 1988 P.6:49 503

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Image Gallery

(Left) Short-axis cine SSFP MR images in diastole (left) and systole (right) show a fibroma as a noncontractile mass arising in the anterior right ventricular wall. (Right) Three-chamber (left) and 4-chamber (right) cine SSFP MR images show the same fibroma originating in the right ventricular free wall and extending to the right ventricular outflow tract. The lesion is solitary and ventricular in origin, and these are classic findings in fibromas.

(Left) Short-axis T1 (left) and T2 (right) MR images show an RV fibroma that is isointense on T1 and hypointense on T2 imaging. The T2 hypointensity is characteristic and likely due to the fibroblasts and abundant collagen composing the lesion. (Right) Comparison of short-axis LGE MR imaging of an RV fibroma with standard inversion recovery (IR) (left) vs. novel black blood IR (right) technique shows that the latter better demonstrates the interface of the lesion with the blood pool.

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(Left) Short-axis T1 (left) and T2 (right) images of an anterior LV fibroma in a 1-year-old infant show that the lesion is isointense on T1 and iso- to mildly hyperintense on T2 imaging. Fibromas in infants and young children may not show the T2 hypointensity commonly seen in adults. (Right) MR perfusion (left) and LGE MR (right) images of LV fibroma reveal absence of lesion hypervascularity on 1st-pass perfusion imaging and intense peripheral lesion enhancement on LGE MR with a central dark core.

Lipomatous Hypertrophy, Interatrial Septum Lipomatous Hypertrophy, Interatrial Septum Suhny Abbara, MD, FSCCT Key Facts Terminology  Lipomatous hypertrophy of interatrial septum  Lipomatous hypertrophy of atrial septum  Massive fatty deposits  Lipomatous hamartoma Imaging  Characteristic dumbbell-shaped lesion sparing the fossa ovalis  Typically, the area with greatest fatty deposition will be superior to fossa ovalis  80% will demonstrate dumbbell shape  Characteristic bright T1 signal with loss of normal bright T1 signal on fat-suppressed sequences  FDG PET shows focal increased FDG uptake  Echogenic lesion within interatrial septum Top Differential Diagnoses  Lipoma  Liposarcoma  Teratoma  Myocardial infarction  Arrhythmogenic right ventricular dysplasia Pathology  No capsule present  Proliferation of fat cells rather than hypertrophy  Mature adipose tissue with cells resembling brown fat  Associated with large amount of epicardial fat and increased body mass index Clinical Issues  Most commonly asymptomatic  Rare reports of association with supraventricular arrhythmias and sudden death  May present as obstructive right atrial mass and exertional dyspnea  Prevalence increases with age

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(Left) Four-chamber view FSE MR image shows a large mass in the posterior atrial septum . The high signal intensity is similar to that of nearby epicardial fat. Note that the signal variation of fat throughout the image is due to surface coils being utilized, and the signal strength is higher near the coils. (Right) Four-chamber view T1WI SE without contrast and without fat saturation demonstrates fat signal intensity within the atrial septal mass . Note presence of signal within the left atrium due to in-plane flow .

(Left) Four-chamber view T1WI SE without contrast but with fat saturation in the same patient demonstrates complete signal dropout within the mass . Signal within the left atrium is due to in-plane flow via the right inferior pulmonary vein . (Right) Four-chamber view T1WI SE C+ with fat saturation in the same patient shows absence of signal , indicating that the mass consists of fat and does not have significant vascularity, consistent with benign lipomatous hypertrophy of the atrial septum. P.6:51

TERMINOLOGY Abbreviations  Lipomatous hypertrophy of interatrial septum (LHIS or LHIAS) Synonyms  Lipomatous hypertrophy of atrial septum  Massive fatty deposits  Lipomatous hamartoma  Lipomatous hyperplasia Definitions  Deposition of excessive amounts of fat within the interatrial septum 506

Diagnostic Imaging Cardiovascular o 1st described in 1964 by Prior  Not a true neoplasm IMAGING General Features  Best diagnostic clue o Characteristically dumbbell-shaped lesion sparing the fossa ovalis  However, it need not have this shape to qualify  Location o Within septum secundum  Spares the fossa ovalis  Size o Typically, 11-28 mm in diameter; can be larger  Cutoff values vary by definition  Range: ˜ 10-15 mm o Normal septum is up to 6 mm thick  Septum at fossa ovalis is ˜ 1mm thick o Amount of fatty deposit increases with age  Morphology o Characteristically, the area of greatest amount of fatty deposition will be superior to fossa ovalis o 80% will demonstrate dumbbell shape Imaging Recommendations  Best imaging tool o Incidental finding that does not require imaging unless 1 imaging modality is not unequivocal and exclusion of mass is required  MR SE or FSE sequences  Protocol advice o SE or FSE sequences without fat saturation followed by otherwise identical sequence with fat saturation Radiographic Findings  Radiography o Chest radiograph is normal CT Findings  NECT o Low-attenuation material posteriorly within otherwise water-density heart o May also demonstrate increased mediastinal and epicardial fat  CTA o Dumbbell-shaped, fat-density lesion that spares fossa ovalis o May be contiguous with epicardial fat o Usually an incidental diagnosis o Multiplanar reconstructions may be helpful to determine caval obstruction MR Findings  Characteristic bright T1 signal with loss of normal bright T1 signal on fat-suppressed sequences  Classic dumbbell shape Nuclear Medicine Findings  PET o FDG PET shows focal increased FDG uptake o Standardized uptake value (SUV) of lipomatous hypertrophy of interatrial septum ˜ 1.6-6.1x greater than SUV of adjacent blood pool o Positive correlation of SUV and thickness of LHIS on CT o Image fusion with CT will confirm location during staging and may avoid pitfall of diagnosing metastatic disease Echocardiographic Findings  Echogenic lesion within interatrial septum  Typically echo-dense globular shape with sparing of fossa ovalis  Often incidental diagnosis that requires no further follow-up o Occasionally, diagnosis is not unequivocal, and further testing (such as MR) may be necessary to exclude cardiac mass DIFFERENTIAL DIAGNOSIS 507

Diagnostic Imaging Cardiovascular Lipoma  Primary cardiac lipomas are rare  True lipoma has fibrous capsule, whereas lipomatous hypertrophy does not  Multiple lipomas may be seen in setting of tuberous sclerosis Liposarcoma  Rare  Usually large, filling entire cavity  Signs of malignancy (e.g., invasion of neighboring structures, mass effect, metastasis) Teratoma  Rare  Demonstrates mass effect  Not dumbbell-shaped  May demonstrate fat or lipid collection but also various other tissues (e.g., soft tissue, hair, teeth, bone) Myocardial Infarction  Linear fat is within myocardium but not within atrial septum Arrhythmogenic Right Ventricular Dysplasia  Fat is typically within right ventricular myocardium o Occasionally within left ventricular myocardium o Virtually never within atrial septum Myxoma  Most common primary cardiac neoplasm  May be adjacent to fossa ovalis but is usually connected to septum via stalk and is mobile  Does not have features of fat on either CT or MR P.6:52

Other Benign Tumors  Rhabdomyoma  Fibroma  Mesothelioma  Typically no fat-density/signal characteristics Thrombus  May adhere to atrial wall  Will not follow characteristics of fat on either CT or MR Metastatic Disease  Usually no fat-density/signal characteristics  Other cardiac or extracardiac metastatic deposits PATHOLOGY General Features  Etiology o Hyperplasia rather than hypertrophy of local fat cells  Associated abnormalities o Associated with large amount of epicardial fat and increased body mass index Gross Pathologic & Surgical Features  If resected, will show features characteristic of mass-like fat deposits o Constrained by normal structures  No capsule present Microscopic Features  Proliferation of fat cells rather than hypertrophy  Mature adipose tissue with cells resembling brown fat  Vacuolated cytoplasm and centrally placed nuclei CLINICAL ISSUES Presentation  Most common signs/symptoms o Most commonly asymptomatic  Other signs/symptoms o Rare reports of association with supraventricular arrhythmias and sudden death o Syncope 508

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May present as obstructive right atrial mass and exertional dyspnea  Obstruction of superior vena cava

Demographics  Age o Prevalence increases with age  Gender o No gender predilection  Reported prevalence: 1-8% o Prevalence of 2.2% on recent prospective CT study  More common in obese persons Natural History & Prognosis  Usually asymptomatic  Rarely may cause obstructive symptoms that necessitate resection Treatment  Usually no treatment is necessary  Rarely resection of obstructive variants  May change type of transcatheter closure device used if concomitant patent foramen ovale or atrial septal defect is present o Amplatzer devices are stiff, and some cannot bridge thickness > 6-7 mm DIAGNOSTIC CHECKLIST Consider  Add fat-saturated T1WI to regular T1WI if differentiating from cardiac masses or metastases, such as melanoma Image Interpretation Pearls  Fat-density material (CT) or signal intensity identical to nearby epicardial fat on all MR pulse sequences in atrial septal location with sparing of fossa ovalis is diagnostic of LHIS SELECTED REFERENCES 1. Lee SH et al: Visceral obesity of the heart: extensive lipomatous hypertrophy of interatrial septum. J Cardiovasc Ultrasound. 20(3):161-2, 2012 2. Rigatelli G et al: Anatomo-functional characterization of interatrial septum for catheter-based interventions. Am J Cardiovasc Dis. 1(3):227-35, 2011 3. Pugliatti P et al: Lipomatous hypertrophy of the interatrial septum. Int J Cardiol. 2007 4. Tugcu A et al: Lipomatous Hypertrophy of the Interatrial Septum Presenting as an Obstructive Right Atrial Mass in a Patient with Exertional Dyspnea. J Am Soc Echocardiogr. 2007 5. Fan CM et al: Lipomatous hypertrophy of the interatrial septum: increased uptake on FDG PET. AJR Am J Roentgenol. 184(1):339-42, 2005 6. Kuester LB et al: Lipomatous hypertrophy of the interatrial septum: prevalence and features on fusion 18F fluorodeoxyglucose positron emission tomography/CT. Chest. 128(6):3888-93, 2005 7. Heyer CM et al: Lipomatous hypertrophy of the interatrial septum: a prospective study of incidence, imaging findings, and clinical symptoms. Chest. 124(6):2068-73, 2003 8. Iacovoni A et al: [Lipomatous hypertrophy of the interatrial septum: its assessment with TEE, CT and MRI.] G Ital Cardiol. 28(11):1273-7, 1998 9. Meaney JF et al: CT appearance of lipomatous hypertrophy of the interatrial septum. AJR Am J Roentgenol. 168(4):1081-4, 1997 10. Burke AP et al: Lipomatous hypertrophy of the atrial septum presenting as a right atrial mass. Am J Surg Pathol. 20(6):678-85, 1996 11. Shirani J et al: Clinical, electrocardiographic and morphologic features of massive fatty deposits (“lipomatous hypertrophy”) in the atrial septum. J Am Coll Cardiol. 22(1):226-38, 1993 12. Lund JT et al: Cardiac masses: assessment by MR imaging. AJR Am J Roentgenol. 152(3):469-73, 1989 13. Simons M et al: Lipomatous hypertrophy of the atrial septum: diagnosis by combined echocardiography and computerized tomography. Am J Cardiol. 54(3):465-6, 1984 14. PRIOR JT: Lipomatous hypertrophy of cardiac interatrial septum: a lesion resembling hibernoma, lipoblastomatosis and infiltrating lipoma. Arch Pathol. 78:11-5, 1964 P.6:53

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(Left) Axial MDCT without contrast demonstrates a low-attenuation lesion within the superior aspect of the atrial septum, measuring ˜ 15 mm in thickness. Hounsfield units are lower than for blood pool (negative numbers), and attenuation is similar to that of epicardial fat. (Right) Axial FDG PET image of the same patient demonstrates abnormal hypermetabolic activity within the lesions, which is characteristic for lipomatous hypertrophy of the atrial septum. This phenomenon is due to the presence of brown fat.

(Left) Coronal (posterior view) FDG PET performed for oncological reasons in the same patient demonstrates focal increased uptake within the region of the atria, corresponding to hypermetabolic brown fat activity within the LHIAS. (Right) Axial CECT at the level of the noncoronary cusp of the aorta demonstrates marked thickening of the atrial septum, which consists of fat-density material. LHIAS often “flares” and appears more prominent in the superior slices of a CT.

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(Left) Axial CECT at the level of the fossa ovalis demonstrates the classic dumbbell configuration of the atrial septum, which is due to the sparing of the fossa ovalis (handle) and fatty hyperplasia of the septum primum anterior and posterior to the fossa. (Right) Coronal CECT in the same patient demonstrates the fat-density lesion posterior to the aortic root and between the right and left atria . Note apparent contiguity with the epicardial fat; also note the extent toward the superior vena cava . P.6:54

(Left) Axial CECT at the level of the fossa ovalis demonstrates a dumbbell configuration of the atrial septum with sparing of the fossa ovalis and fat attenuation thickening anteriorly and posteriorly. (Right) Axial FDG PET in the same patient demonstrates hypermetabolic activity within the atrial septum, corresponding to the LHIAS, a finding that can lead to false-positive interpretation on oncology studies unless recognized.

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(Left) Axial PD FSE MR without fat saturation demonstrates high signal intensity within the thin anterior portion and mass-like posterior portion of the atrial septum , which extends to the crista terminalis . LHIAS may mimic cardiac neoplasms. Note large amount of epicardial fat . (Right) Axial fat-saturated FSE MR demonstrates signal dropout within the thin anterior portion and mass-like posterior portion of the atrial septum , indicating that the lesion is composed of simple fat.

(Left) Four-chamber view SSFP image shows the high signal intensity mass outlined in black (India ink phenomenon) due to the interface of fat-containing and water-containing voxels. (Right) Axial C+ 1st-pass perfusion MR in the same patient at the same level demonstrates absence of enhancement of the mass. Combined, these findings characterize the mass as (asymmetric) benign lipomatous hypertrophy of the atrial septum. P.6:55

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(Left) Axial black-blood SE MR at the level of the aortic root demonstrates a large amount of epicardial fat that is in continuity with LHIAS at the level of the superior vena cava and right atrial junction . (Right) Four-chamber view SSFP image shows the high signal intensity lesions , outlined by an India ink artifact, with sparing of the fossa ovalis resulting in the classic dumbbell shape of LHIAS. Note fatty replacement of the right ventricular free wall .

(Left) Axial FSE MR shows a fat-containing thickened atrial septum . The pericardium separates pericardial fat from a large amount of epicardial fat . Note fatty replacement of the right ventricular free wall myocardium . Also note crista terminalis . (Right) Axial FSE MR with fat saturation demonstrates signal dropout of the atrial septum , pericardial fat , and epicardial fat . Fatty replaced outer portion of the right ventricular free wall myocardium is now also nulled.

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(Left) Axial CECT shows lipomatous hypertrophy of the upper portion of the atrial septum above the fossa ovalis with fat-density material between the right atrium and left atrium and posterior to the noncoronary cusp of the aortic valve. (Right) Axial CECT in the same patient at the level of the fossa ovalis demonstrates normal thickness of the atrial septum, indicating a partial sparing or incomplete nature of LHIAS. Note the incidental presence of a hiatal hernia .

Lymphoma Lymphoma John P. Lichtenberger, III, MD Key Facts Terminology  Primary cardiac lymphoma  Secondary cardiac lymphoma  Primary effusion lymphoma Imaging  Ill-defined, infiltrative mass involving myocardium or pericardium, often with pericardial effusion  Right atrium is most frequently involved  Radiography o Enlarged cardiac silhouette o Lymphadenopathy  Cardiac gated CT o Low-attenuation infiltrative myocardial masses o Right heart involvement o Encasement of coronary arteries o Pericardial effusion o May miss diffuse myocardial infiltration without cavitary component  MR o Superior tissue characterization o High spatial resolution o Multiple nodular, relatively hyperintense masses infiltrating myocardium Top Differential Diagnoses  Metastatic disease  Thrombus  Other primary cardiac tumors Clinical Issues  Cardiac arrhythmia  Heart failure Diagnostic Checklist  Rapidly progressive and treatment-resistive congestive heart failure may be 1st presenting symptom 514

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(Left) PA chest radiograph of a patient with lymphoma shows an anterior mediastinal mass distorting the cardiac silhouette. Enlargement of the cardiac silhouette in patients with lymphoma may be due to cardiomegaly, pericardial effusion, or a mediastinal mass. (Right) Axial CECT of the same patient shows a heterogeneous anterior mediastinal mass that involves the right atrium and right atrial appendage . Pericardial effusion supports the diagnosis of secondary cardiac lymphoma.

(Left) Axial CECT of a patient with HIV-associated primary cardiac lymphoma shows low-attenuation infiltrative masses within the left ventricular myocardium. Pericardial effusion is also present. Multiple infiltrative masses are the most common presentation of cardiac lymphoma. (Right) FDG PET of the same patient shows increased FDG activity in the same distribution as the infiltrative low-attenuation masses on CT. P.6:57

TERMINOLOGY Definitions  Primary cardiac lymphoma o Confined to heart and pericardium without extracardiac disease o Non-Hodgkin lymphoma o Rare o Majority occur in HIV/AIDS patients  Secondary cardiac lymphoma o Cardiac involvement in patients with systemic lymphoma o ˜ 1/3 of lymphoma patients develop secondary cardiac lymphoma (on pathology series)  Primary effusion lymphoma 515

Diagnostic Imaging Cardiovascular o o o

Rare, HIV-associated non-Hodgkin lymphoma Lymphomatous growth in liquid phase in body cavities, such as pericardium Evidence of infection by human herpesvirus-8, which is associated with Kaposi sarcoma

IMAGING General Features  Best diagnostic clue o Ill-defined, infiltrative mass involving myocardium or pericardium, often with pericardial effusion o Extension along epicardial surface o Encasement of coronary arteries and aortic root  Location o Right atrium is most frequently involved, followed by right ventricle, left ventricle and atrium, and interatrial septum o Predilection for right atrioventricular groove o Secondary lymphoma most commonly has pericardial involvement o May involve myocardium diffusely  Can mimic hypertrophic cardiomyopathy o Often with intracavitary component  Frequently nodular or lobulated o Epicardial involvement often demonstrates encasement of coronary arteries o Can involve pericardial space exclusively o Secondary cardiac lymphoma will have other noncardiac foci o Primary cardiac lymphoma is reported to be more common in right atrium  Size o Variable but often large; fills most of affected cavity  Morphology o Frequently manifests as ill-defined, infiltrative mass Radiographic Findings  May demonstrate lymphadenopathy  Enlargement of cardiac silhouette may indicate cardiomegaly, pericardial effusion, or mass  Signs of congestive heart failure (right ventricular, left ventricular, or biventricular failure, depending on involved structures) CT Findings  Cardiac gated CTA o Superior to nongated CT  Hypo- or isoattenuating with respect to myocardium  May miss diffuse myocardial infiltration without cavitary component  Lobular mass with heterogeneous enhancement  May demonstrate other manifestations of lymphoma, which then would indicate that cardiac involvement is secondary MR Findings  Superior tissue characterization  High spatial resolution  Typical presentations of primary cardiac lymphoma o Multiple nodular, relatively hyperintense masses infiltrating myocardium o Diffuse infiltration of pericardium with hemorrhagic pericardial effusion o Usually heterogeneous enhancement  T1- and T2-weighted sequence may show diffusely infiltrating lymphoma as isointense, which makes it difficult to determine its extent  T1 C+ MR and late gadolinium enhancement imaging may improve contrast between brighter mass and nulled myocardium  Predominantly intraluminal masses are readily detected on white blood cine sequences o May demonstrate jets from flow obstruction  May demonstrate encasement of coronary arteries  May be used to monitor treatment success/remission and recurrence  Chamber enlargement if obstructing physiology  Pericardial effusions may result in tamponade Echocardiographic Findings  Transthoracic echocardiography for initial evaluation of suspected cardiac mass 516

Diagnostic Imaging Cardiovascular  Hypoechoic mass infiltrating right heart  Pericardial effusion  Transesophageal echocardiography is superior to transthoracic echocardiography Imaging Recommendations  Best imaging tool o Cardiac gated MR  Protocol advice o White blood cine images to assess for flow obstruction o T1-weighted spin-echo sequences pre and post gadolinium (with identical spatial locations) to assess for abnormal enhancement o Late gadolinium enhancement imaging may improve contrast between unaffected and infiltrated myocardium DIFFERENTIAL DIAGNOSIS Metastatic Disease  40x more common than all primary cardiac neoplasms combined  Lung cancer is most common given prevalence  Metastatic malignant melanoma has high incidence of cardiac involvement Thrombus  Bland or tumor thrombus should be considered in cardiac mass cases  Bland thrombus is more common in left atrium and left atrial appendage P.6:58  Tumor thrombus results from extracardiac mass extending to atria via transvenous spread Other Primary Cardiac Tumors  Myxoma o Most common primary cardiac tumor o Characteristic stalk-like attachment to interatrial septum near foramen ovalis o Most commonly located in left atrium o Low-grade patchy enhancement o Bright on T2WI  Sarcoma o Most common primary cardiac malignancy o 2nd most common of all (benign or malignant) primary cardiac tumors after myxoma o May be distinguished by prominent enhancement  Leiomyoma, rhabdomyoma, fibroma, hemangioma, lipoma, etc. Nonneoplastic Disorders  Hypertrophic cardiomyopathy Pericardial Disease  Infectious or inflammatory pericarditis  Neoplastic pericardial disease PATHOLOGY General Features  Etiology o Primary cardiac/pericardial involvement by T-cell phenotype has been described in post (noncardiac) transplant patients o HIV/AIDS  Isolated cardiac tumors in HIV/AIDS are typically primary lymphomas  Primary cardiac non-Hodgkin lymphoma is 25-60x more common than in general population  Secondary cardiac tumors are often due to widespread Kaposi sarcoma Gross Pathologic & Surgical Features  Multiple firm nodules  Contiguous invasion of pericardium Microscopic Features  Immunophenotypic studies may allow differentiation of lymphoma from metastatic carcinoma or angiosarcoma CLINICAL ISSUES 517

Diagnostic Imaging Cardiovascular Presentation  Most common signs/symptoms o Cardiac arrhythmia o Dyspnea, chest pain, syncope o Heart failure o Pericardial effusion  Other signs/symptoms o Nonspecific ECG changes, such as atrioventricular block o May rapidly progress o May be occult until presenting with cardiac tamponade o Secondary lymphoma is frequently occult in vivo and detected postmortem o Sudden death Demographics  Age o Primary cardiac lymphoma: Mean age of 60 years  Gender o Slight male predominance in primary cardiac lymphoma  Epidemiology o Primary cardiac lymphoma has incidence of 0.06% in general population on pathology series o Increasing prevalence due to Epstein-Barr virus-related lymphoproliferative disorders  Transplant recipients, particularly heart- and lung-transplant patients o Only 1.3% of all primary cardiac tumors are primary cardiac lymphoma o 0.5% of extranodal lymphomas are primary cardiac lymphoma o Primary effusion lymphoma accounts for 4% of all HIV-associated non-Hodgkin lymphomas Natural History & Prognosis  Secondary lymphoma is frequently not apparent clinically  T-cell lymphomas invade heart more frequently and are more aggressive than B-cell lymphomas o T-cell lymphomas are more likely to have cardiac manifestations  Clinical outcome of primary cardiac lymphoma is variable o Early diagnosis and treatment improves prognosis and may result in complete remission o Prognosis of HIV-associated primary cardiac lymphoma is poor Treatment  Primary cardiac lymphoma: Chemotherapy and monoclonal anti-CD20 antibody ± radiation  Autologous stem cell transplant has been described  Pericardial drainage if tamponade  Surgical debulking in some cases DIAGNOSTIC CHECKLIST Consider  Rapidly progressive and treatment-resistive congestive heart failure may be 1st presenting symptom Image Interpretation Pearls  Additional imaging of abdomen and pelvis may reveal other lymphomatous involvement and change the diagnosis from primary to secondary cardiac lymphoma SELECTED REFERENCES 1. Jeudy J et al: From the radiologic pathology archives: cardiac lymphoma: radiologic-pathologic correlation. Radiographics. 32(5):1369-80, 2012 2. Shah RN et al: Primary cardiac lymphoma diagnosed by multiphase-gated cardiac CT and CT-guided percutaneous trans-sternal biopsy. J Cardiovasc Comput Tomogr. 6(2):137-9, 2012 P.6:59

Image Gallery

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(Left) AP chest radiograph of a patient with HIV-associated primary cardiac lymphoma shows only mild enlargement of the cardiac silhouette. (Right) Axial CECT of the same patient shows an infiltrating lobulated heterogeneously enhancing mass within the anterior atrioventricular groove encasing, but not obstructing, the right coronary artery . Contiguous lobulated masses in the right atrium have intrachamber components .

(Left) Axial CECT of a patient with cardiac lymphoma shows a heterogeneously enhancing mass centered in the right atrium near the crux of the heart with associated pericardial effusion and pericardial enhancement. Cardiac lymphoma has a predilection for the right atrium. (Right) T1WI C+ with fat saturation of the same patient shows a lobulated mass in the right atrium with infiltration into the interventricular septum and low signal intensity relative to enhancing myocardium.

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(Left) Sagittal CECT of a patient with history of lymphoma shows a calcified mass along the right ventricular outflow tract and anterior interventricular groove. Calcification is not uncommon in cases of treated lymphoma. (Right) Sagittal T1 FSE of the same patient shows low signal within the mass , consistent with a known calcification in a treated lymphoma. MR may be useful in monitoring treatment response and recurrence.

Section 7 - Cardiomyopathy Imaging of Cardiomyopathies: The Evidence Introduction Cardiomyopathy refers to a primary disease of the myocardium that can result in systolic &/or diastolic dysfunction and manifest in congestive heart failure. The World Health Organization classification of cardiomyopathies includes etiologies such as ischemic, nonischemic, restrictive, hypertrophic, inflammatory, valvular, hypertensive, and metabolic. The accurate identification of the cause of the cardiomyopathy has important implications for prognosis and treatment. Noninvasive cardiac imaging is a critical part of the evaluation of patients with cardiomyopathy. Echocardiography is often the primary modality used in the initial evaluation of patients with heart failure, though its ability to accurately characterize myocardial tissue and determine the underlying etiology is often limited. Advanced imaging modalities such as cardiac MR, cardiac CT, and cardiac PET are increasingly used in the diagnostic evaluation of cardiomyopathies. With increased attention on the cost and cost-effectiveness of cardiac imaging there will be increased scrutiny on the evidence base supporting the clinical utility of these imaging techniques. The following is a brief summary of the evidence supporting the use of advanced imaging modalities such as cardiac MR and cardiac CT for the evaluation of various cardiomyopathies. For more detailed information, the reader is directed to the references cited. Ischemic Cardiomyopathy Cardiac MR with late gadolinium enhancement (LGE) has become the gold standard for the noninvasive detection of myocardial infarction owing to its superior spatial resolution and signal to noise contrast when compared with other modalities, such as echocardiography and nuclear imaging. Many publications note that the presence of myocardial infarct as detected by cardiac MR is associated with a worse prognosis with regard to major adverse cardiac events. In the ICELAND MI study, the prevalence of unrecognized myocardial infarction by cardiac MR was greater than the prevalence of recognized myocardial infarction and was independently associated with mortality. Whether the detection of myocardial infarction by cardiac MR leads to improved outcomes through adjustments in therapy requires additional clinical trials. In the evaluation of a newly diagnosed cardiomyopathy, one of the first considerations is the presence of obstructive coronary artery disease. There are several modalities for the detection of obstructive coronary artery disease. Exercise treadmill testing, nuclear stress testing, and stress echocardiography have been in widespread use for decades. Stress perfusion by cardiac MR and cardiac CT have demonstrated excellent diagnostic and prognostic utility across a range of clinical indications. In the evaluation of newly diagnosed heart failure, the most recent (2010) criteria for cardiac CT give an appropriate grade for the use of cardiac CT in the evaluation of patients with heart failure who face a low to intermediate risk of coronary artery disease. Similarly, Assomull et al. showed in a study of 120 patients with cardiomyopathy who underwent cardiac MR and coronary angiography that cardiac MR would perform well as a 520

Diagnostic Imaging Cardiovascular gatekeeper to angiography and thereby limit the cost and risk of cardiac catheterization. In this analysis, a protocol using LGE and coronary MR angiography was employed. In patients with ischemic cardiomyopathy, the role of revascularization is controversial given the results of the STICH study, which showed similar outcomes in patients undergoing surgery compared with medical therapy. Viability was included as a substudy, though it did not include cardiac MR or cardiac PET, i.e., modalities that may perform better when compared with echocardiography or thallium imaging. Prior data from Kim et al. shows that the degree of transmural enhancement is associated with the likelihood of segmental functional recovery after revascularization. Data from Ling et al. shows that in patients with hibernating myocardium there may be a survival benefit from revascularization with PET. A prospective, randomized trial of cardiac MR and PET to guide revascularization is necessary to determine the role of these techniques in the management of ischemic cardiomyopathy. Nonischemic Dilated Cardiomyopathy Using registry data from EuroCMR, Bruder et al. (2009) demonstrated in a large cohort of patients that cardiac MR had a direct impact on diagnostic and therapeutic management in approximately two-thirds of the patients. In addition, a new diagnosis was provided by cardiac MR in approximately 9% of the cases. In this cohort study, approximately onethird of patients underwent evaluation of a cardiomyopathy &/or myocarditis. In addition to the diagnostic yield of cardiac MR, there is growing evidence of the prognostic value in various cardiomyopathies. Gulati et al. reported in a prospective longitudinal study of 472 patients with dilated cardiomyopathy that the presence of myocardial fibrosis by LGE was an independent predictor of mortality and sudden cardiac death. The use of implantable cardioverter-defibrillators and cardiac resynchronization therapy, also known as biventricular pacing, has been shown to improve the survival in patients with both ischemic and nonischemic cardiomyopathies. Despite this clear benefit, appropriate patient selection remains a challenge. In the case of implantable cardioverterdefibrillators, current guidelines use left ventricular ejection fraction (LVEF) to predict who would benefit, though ejection fraction is not a good predictor of an individual's risk of sudden cardiac death. A recent meta-analysis by Scott et al. shows that the extent of LGE is strongly associated with the risk of sudden cardiac death in patients with low ejection fraction and may prove to be useful in selecting patients for implantable cardioverter-defibrillator therapy. Additional prospective clinical trials are necessary. Similarly, with cardiac resynchronization therapy it is recognized that the nonresponse rate can be as high as 40%. Various echocardiographic techniques, such as M-mode, tissue Doppler imaging, speckle tracking, and 3D imaging, have been used to quantify the degree of myocardial dyssynchrony by measuring myocardial strain. Similarly, techniques in cardiac MR and CT can also measure the degree of dyssynchrony. At this time, however, no imaging technique has been shown to adequately predict response to cardiac resynchronization therapy. Ongoing clinical trials may clarify the role of advanced modalities such as cardiac MR and cardiac CT. P.7:3

Hypertrophic Cardiomyopathy In a review of the performance of cardiac MR in hypertrophic cardiomyopathy, Noureldin et al. report that echocardiography may underestimate the degree of wall thickness and may be limited in specific patterns of hypertrophy, such as apical hypertrophic cardiomyopathy. Many hypertrophic cardiomyopathy centers now routinely use cardiac MR for the diagnosis and evaluation of hypertrophic cardiomyopathy. Several groups have reported the presence of LGE in hypertrophic cardiomyopathy and its association with adverse events. Noureldin et al. report a 65% combined incidence of LGE in hypertrophic cardiomyopathy from 18 studies. Similarly, Green et al. report in a meta-analysis of 1,063 patients that the prevalence of LGE was 60% and was associated with risk of cardiac death and all-cause mortality. Cardiac Sarcoidosis In patients with sarcoidosis, cardiac involvement is the leading cause of death, highlighting the importance of accurate diagnosis. Patel et al. demonstrate that in a cohort of 81 patients, 26% had cardiac involvement by LGE compared with only 12% using Japanese Ministry of Health criteria; in addition, LGE was associated with an increase risk of cardiac events. Similarly, Greulich et al. demonstrate that the presence of LGE is the best independent predictor of potentially life-threatening arrhythmias and that the absence of LGE is associated with a very low event rate. Amyloidosis Historically, the diagnosis of cardiac amyloid relied on endomyocardial biopsy. Cardiac MR now allows for the use of a noninvasive method that performs better than echocardiography alone. Syed et al. performed cardiac MR with LGE in 120 patients with systemic amyloidosis. Of those with histologically confirmed cardiac amyloidosis, abnormal LGE was present in 97%. Of those without known cardiac amyloidosis and a normal wall thickness on echocardiography, 47% had abnormal LGE, suggesting a greater sensitivity of cardiac MR. LGE was also associated with clinical markers of poor prognosis. Banypersad et al. and Mongeon et al. describe methods of calculating the extracellular volume fraction using T1 mapping techniques. These techniques are more sensitive to diffuse myocardial processes, such as cardiac 521

Diagnostic Imaging Cardiovascular amyloidosis. Mongeon et al. demonstrate that patients with cardiac amyloidosis have a significantly elevated extracellular volume fraction compared with controls. Banypersad et al. show that extracellular volume measurement is higher even in patients without focal LGE, suggesting that this may be a more sensitive diagnostic technique. Further studies are necessary to define the diagnostic utility and role of extracellular volume quantification in tracking disease activity. Myocarditis Friedrich et al. describe the diagnostic performance of cardiac MR in patients with suspected myocarditis. The Lake Louise Criteria describe the three cardiac MR criteria currently used: Early global relative enhancement, myocardial edema by T2, and LGE. Using pooled data, the sensitivity and specificity with two out of three positive criteria are 67% and 91%, respectively. Of note, the gold standard in these studies was either a clinical assessment or histology from endomyocardial biopsy, both of which have their limitations. Lurz et al. report the largest prospective study of 132 consecutive patients with suspected myocarditis who underwent both cardiac MR and endomyocardial biopsy and demonstrate that the Lake Louise Criteria performed better than LGE alone. Diagnostic performance was higher in patients with acute presentations and those with a myocardial infarction-like presentation. In patients with symptoms persisting for more than 14 days, diagnostic performance was poor (sensitivity was 63%, and specificity was 40%). Left Ventricular Noncompaction Left ventricular noncompaction is a genetic cardiomyopathy characterized by an increase in the noncompacted myocardial layer and can lead to heart failure, arrhythmias, and embolic complications. The currently used cardiac MR criteria for left ventricular noncompaction (noncompacted to compacted ratio of > 2.3 in diastole) was first described by Petersen et al. in 2005 in a study including seven patients with established left ventricular noncompaction compared with healthy controls, athletes, and patients with aortic stenosis, hypertrophic cardiomyopathy, and dilated cardiomyopathy. Concern about the specificity of these criteria emerged given the small size of this study. Kawel et al. reported on the prevalence of an elevated ratio in the large population-based Multi-Ethnic Study of Atherosclerosis (MESA) cohort. In a group of 323 adults without cardiac disease or hypertension 43% had at least 1 myocardial segment with a noncompacted to compacted ratio > 2.3, while 6% had greater than 2 segments. The most common location of prominent trabeculations in this healthy cohort was the apical lateral and mid anterior segments. There was a negative correlation between the noncompacted to compacted ratio and ejection fraction and a positive correlation with left ventricular end diastolic and end systolic dimensions. Arrhythmogenic Right Ventricular Cardiomyopathy Arrhythmogenic right ventricular cardiomyopathy (previously referred to as arrhythmogenic right ventricular dysplasia) is a genetic condition characterized by fibrofatty replacement of the right ventricle (and, rarely, of the left ventricle) that can increase the risk of sudden cardiac death. In 2006, Marcus et al. reported the revised task force criteria for arrhythmogenic right ventricular cardiomyopathy, which emphasizes a regional right ventricular wall motion abnormality with associated right ventricular dilatation &/or dysfunction. Of note, the presence of intramyocardial fat by T1-weighted imaging is not part of the imaging criteria. Studies have shown a variable prevalence of intramyocardial fat, with Tandri et el. reporting ranges from 22% to 100% depending on the cohort and technique utilized. The limited spatial and contrast resolution can be particularly challenging when trying to distinguish intramyocardial fat from epicardial fat with the thin-walled right ventricle. Vermi et al. examined the performance of the revised criteria compared with the older criteria in a cohort of 294 patients who underwent cardiac MR. They found that the new P.7:4 imaging criteria were associated with a lower sensitivity and maintained a high specificity. It is important to note that a diagnosis of arrhythmogenic right ventricular cardiomyopathy requires a combination of clinical and imaging criteria. Iron Overload Syndromes In iron overload syndromes, such as the thalassemias, the leading cause of death is often cardiac, highlighting the importance of reliable noninvasive methods for quantification of myocardial iron content. In 2001, Anderson et al. reported the utility of myocardial T2*, which is now widely used for measuring myocardial iron content. Modell et al. demonstrated that the use of cardiac MR was associated with improved survival of patients with thalassemia major in the United Kingdom, marking one of the few scenarios where a cardiac imaging strategy has been shown to correlate with improved survival. Cost-Effectiveness Given the economic climate within the United States and in many nations across the world, there is increased pressure to demonstrate the cost-effectiveness of a particular imaging technique and the associated impact on patient outcomes. Carefully conducted clinical trials can be costly, and retrospective analyses can be limited given the challenges in modeling downstream decision making after an imaging test. With regard to the use of advanced imaging modalities like cardiac MR, cardiac CT, and cardiac PET in the evaluation of cardiomyopathy, studies such the IMAGE-HF study led by investigators at the University of Ottawa will help clarify the relationship between various imaging strategies and subsequent outcomes including resource utilization. 522

Diagnostic Imaging Cardiovascular Selected References 1. Banypersad SM et al: Quantification of myocardial extracellular volume fraction in systemic AL amyloidosis: an equilibrium contrast cardiovascular magnetic resonance study. Circ Cardiovasc Imaging. 6(1):34-9, 2013 2. Bruder O et al: European Cardiovascular Magnetic Resonance (EuroCMR) registry—multi national results from 57 centers in 15 countries. J Cardiovasc Magn Reson. 15:9, 2013 3. Greulich S et al: CMR imaging predicts death and other adverse events in suspected cardiac sarcoidosis. JACC Cardiovasc Imaging. 6(4):501-11, 2013 4. Gulati A et al: Association of fibrosis with mortality and sudden cardiac death in patients with nonischemic dilated cardiomyopathy. JAMA. 309(9):896-908, 2013 5. Ling LF et al: Identification of therapeutic benefit from revascularization in patients with left ventricular systolic dysfunction: inducible ischemia versus hibernating myocardium. Circ Cardiovasc Imaging. 6(3):363-72, 2013 6. Scott PA et al: Late gadolinium enhancement cardiac magnetic resonance imaging for the prediction of ventricular tachyarrhythmic events: a meta-analysis. Eur J Heart Fail. Epub ahead of print, 2013 7. Green JJ et al: Prognostic value of late gadolinium enhancement in clinical outcomes for hypertrophic cardiomyopathy. JACC Cardiovasc Imaging. 5(4):370-7, 2012 8. Heydari B et al: Imaging for planning of cardiac resynchronization therapy. JACC Cardiovasc Imaging. 5(1):93-110, 2012 9. Kawel N et al: Trabeculated (noncompacted) and compact myocardium in adults: the multi-ethnic study of atherosclerosis. Circ Cardiovasc Imaging. 5(3):357-66, 2012 10. Lurz P et al: Diagnostic performance of CMR imaging compared with EMB in patients with suspected myocarditis. JACC Cardiovasc Imaging. 5(5):513-24, 2012 11. Mongeon FP et al: Quantification of extracellular matrix expansion by CMR in infiltrative heart disease. JACC Cardiovasc Imaging. 5(9):897-907, 2012 12. Noureldin RA et al: The diagnosis of hypertrophic cardiomyopathy by cardiovascular magnetic resonance. J Cardiovasc Magn Reson. 14:17, 2012 13. Schelbert EB et al: Prevalence and prognosis of unrecognized myocardial infarction determined by cardiac magnetic resonance in older adults. JAMA. 308(9):890-6, 2012 14. Assomull RG et al: Role of cardiovascular magnetic resonance as a gatekeeper to invasive coronary angiography in patients presenting with heart failure of unknown etiology. Circulation. 124(12):1351-60, 2011 15. Bonow RO et al: Myocardial viability and survival in ischemic left ventricular dysfunction. N Engl J Med. 364(17):1617-25, 2011 16. Carpenter JP et al: On T2* magnetic resonance and cardiac iron. Circulation. 123(14):1519-28, 2011 17. Velazquez EJ et al: Coronary-artery bypass surgery in patients with left ventricular dysfunction. N Engl J Med. 364(17):1607-16, 2011 18. Vermes E et al: Impact of the revision of arrhythmogenic right ventricular cardiomyopathy/dysplasia task force criteria on its prevalence by CMR criteria. JACC Cardiovasc Imaging. 4(3):282-7, 2011 19. Marcus FI et al: Diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia: proposed modification of the task force criteria. Circulation. 121(13):1533-41, 2010 20. Syed IS et al: Role of cardiac magnetic resonance imaging in the detection of cardiac amyloidosis. JACC Cardiovasc Imaging. 3(2):155-64, 2010 21. Taylor AJ et al: ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 appropriate use criteria for cardiac computed tomography. A report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. J Am Coll Cardiol. 56(22):1864-94, 2010 22. Bruder O et al: EuroCMR (European Cardiovascular Magnetic Resonance) registry: results of the German pilot phase. J Am Coll Cardiol. 54(15):1457-66, 2009 23. Friedrich MG et al: Cardiovascular magnetic resonance in myocarditis: A JACC White Paper. J Am Coll Cardiol. 53(17):1475-87, 2009 24. Patel MR et al: Detection of myocardial damage in patients with sarcoidosis. Circulation. 120(20):1969-77, 2009 25. Modell B et al: Improved survival of thalassaemia major in the UK and relation to T2* cardiovascular magnetic resonance. J Cardiovasc Magn Reson. 10:42, 2008 26. Tandri H et al: Role of magnetic resonance imaging in arrhythmogenic right ventricular dysplasia: insights from the North American arrhythmogenic right ventricular dysplasia (ARVD/C) study. Am Heart J. 155(1):147-53, 2008. Erratum in: Am Heart J. 155(2):289, 2008 27. Petersen SE et al: Left ventricular non-compaction: insights from cardiovascular magnetic resonance imaging. J Am Coll Cardiol. 46(1):101-5, 2005

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Image Gallery

(Left) Short-axis MR perfusion image during vasodilator stress shows a large perfusion defect involving the mid inferior and inferolateral segments . (Right) Short-axis late gadolinium enhancement (LGE) from the same patient shows subendocardial areas of LGE involving the mid inferior and inferolateral segments. Taken together with the stress perfusion image, the study is consistent with a small prior inferior and inferolateral myocardial infarction with significant peri-infarct ischemia.

(Left) Four-chamber view MR cine shows a large area of wall thinning and severe hypokinesis/akinesis involving the mid to distal septum and apex . (Right) Four-chamber view LGE shows a large, nearly transmural infarct affecting the mid left anterior descending (LAD) territory . Cardiac catheterization showed a chronic total occlusion of the LAD. Given the transmural extent of LGE (> 50%) and the low likelihood of segmental functional improvement, the patient was medically managed.

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(Left) Four-chamber view LGE image is from a 65-year-old man with significant peripheral arterial disease and a newonset cardiomyopathy. Absence of LGE suggests a nonischemic etiology of his cardiomyopathy. (Right) Coronary angiogram showed no significant obstructive disease of the LAD , left circumflex , and right coronary (not shown) arteries. This case illustrates the potential role of cardiac MR as a gatekeeper to cardiac catheterization in the evaluation of a cardiomyopathy. P.7:6

(Left) Vertical long-axis (2-chamber) MR cine shows severe left ventricular (LV) systolic dysfunction (LVEF = 30%) in a patient presenting with sustained ventricular tachycardia. (Right) Short-axis LGE image shows a linear pattern of midwall LGE involving the mid anteroseptum and inferoseptum . This pattern is consistent with a nonischemic dilated cardiomyopathy and has been shown to be an independent predictor of outcomes, including all-cause mortality.

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(Left) Short-axis T2WI FSE MR shows extensive increased signal intensity involving the basal septum and right ventricular (RV) free wall , consistent with myocardial edema. (Right) Short-axis LGE image shows corresponding extensive LGE involving the RV free wall , the basal septum and anterior wall , and a small portion of the basal inferior wall . This patient presented with symptomatic ventricular tachycardia and history of pulmonary sarcoid, with MR showing extensive cardiac involvement.

(Left) Cardiac PET study after the patient had implantable cardioverter-defibrillator shows heterogeneous perfusion of the basal septum . FDG images show intense uptake involving the basal anteroseptum and anterior wall and the RV free wall , consistent with cardiac sarcoid with active inflammation. (Right) Axial cardiac PET image (same patient) shows intense FDG uptake involving the RV free wall and LV septum . Cardiac MR and cardiac PET are complimentary modalities in the evaluation of sarcoids. P.7:7

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(Left) Short-axis MR cine shows significant asymmetric upper septal hypertrophy with maximal end-diastolic wall thickness of 23 mm. (Right) Short-axis LGE image from the same patient shows 2 foci of LGE involving the anterior and posterior RV insertion sites. This pattern of LV hypertrophy and LGE is consistent with hypertrophic cardiomyopathy. LGE is associated with increased cardiac event rates in published series.

(Left) Axial T1-weighted image is used for the evaluation of myocarditis. The early global relative enhancement ratio is calculated by comparing the contrast enhancement in the myocardium relative to skeletal muscle . A ratio > 4 is abnormal. In this case, the ratio was 7. (Right) Short-axis LGE image shows a small focus of LGE in an epicardial distribution of the mid inferior wall . Collectively, the findings are consistent with myocarditis.

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(Left) Four-chamber view MR cine shows significant increase in LV and RV trabeculations. The ratio of noncompacted to compacted myocardium exceeds 2.3 in several myocardial segments, consistent with LV noncompaction. (Right) Short-axis T2* GRE MR image was performed for the evaluation of iron overload in a patient with thalassemia and congestive heart failure. The T2* of the myocardium was 8 milliseconds, and the T2* of the liver was 2 milliseconds; both values are consistent with iron overload.

Hypertrophic Cardiomyopathy Key Facts Terminology  Hypertrophic cardiomyopathy (HCM) o Hypertrophic obstructive cardiomyopathy or idiopathic hypertrophic subaortic stenosis when left ventricular outflow tract (LVOT) obstruction is present  Genetic disease affecting proteins of myocardial sarcomere and associated myofilaments Imaging  Most common diagnostic criterion of HCM is left ventricular (LV) wall thickness > 15 mm, but degree of hypertrophy can vary  Most common location is basal septal hypertrophy with other patterns including concentric, midcavitary, and apical  MR: Provides superior spatial resolution; indicated when echocardiography is limited or nondiagnostic o Late gadolinium enhancement (LGE) can be diffuse or focal; often involves segments with most hypertrophy as well as right ventricular insertion sites  Cardiac CT: Can be used in patients with nondiagnostic echocardiography and contraindication to MR Top Differential Diagnoses  Systemic arterial hypertension  Athlete's heart  Infiltrative cardiomyopathy Clinical Issues  Established sudden cardiac death (SCD) risk factor on imaging: Maximal LV wall thickness ≥ 30 mm  Potential SCD risk factors on imaging: LVOT obstruction, LGE on cardiovascular MR, LV aneurysm

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(Left) Short-axis MR cine image in end diastole shows asymmetric increased anterior septal wall thickness consistent with hypertrophic cardiomyopathy (HCM) with upper septal hypertrophy . (Right) Short-axis late gadolinium enhancement image from the same patient shows diffuse, patchy late gadolinium hyperenhancement involving the area of maximal hypertrophy .

(Left) Three-chamber view MR cine image in diastole shows hypertrophic cardiomyopathy with asymmetric increased thickness of the “upper septum” adjacent to the left ventricular outflow tract. Asymmetric septal hypertrophy is the most common morphologic variant of HCM. (Right) Vertical long-axis (2-chamber) MR cine image in end diastole shows hypertrophic cardiomyopathy with focal left ventricular hypertrophy involving the basal to mid anterior wall. P.7:9

TERMINOLOGY Abbreviations  Hypertrophic cardiomyopathy (HCM) Synonyms  When left ventricular (LV) outflow tract (LVOT) obstruction is present, disease is referred to as o Hypertrophic obstructive cardiomyopathy (HOCM) o Idiopathic hypertrophic subaortic stenosis (IHSS) Definitions  Genetic disease affecting proteins of myocardial sarcomere and associated myofilaments o LV hypertrophy without secondary cause  Hypertrophy can be present in various patterns, such as asymmetric septal (most common), concentric, midcavitary, or apical IMAGING 529

Diagnostic Imaging Cardiovascular General Features  Best diagnostic clue o Hallmark is myocardial hypertrophy that cannot be explained by another disease (e.g., hypertension, aortic stenosis, infiltrative process such as amyloidosis)  Most common diagnostic criterion of HCM is LV wall thickness > 15 mm although HCM can be present with any degree of hypertrophy  Location o Variable degree and distribution of LV hypertrophy in HCM  Most commonly, basal septal hypertrophy ± LVOT obstruction  Asymmetric septal hypertrophy (ASH) is commonly defined by ratio of wall thickness of septum to nonhypertrophied segment > 1.3  Apical variant: Apical hypertrophy  Size o LV mass may be increased  Morphology o LV cavity size is typically normal with hyperdynamic systolic function o LV dilatation and systolic dysfunction can develop in small percentage of patients Radiographic Findings  Radiography o Variable findings  Cardiac silhouette can be normal to enlarged  Left atrial (LA) enlargement (right retrocardiac double density) can be seen, especially when significant mitral regurgitation is present MR Findings  Pattern and extent of LV hypertrophy can be variable  Late gadolinium enhancement (LGE) represents areas of increased fibrosis o Can be diffuse or focal and often involves segments with the most severe hypertrophy o Can often be seen at anterior and posterior right ventricular (RV) insertion sites (junction of RV and septum) o Full-thickness or transmural LGE can be seen in “burned out” HCM with associated wall thinning o LGE is associated with markers of risk of sudden cardiac death and cardiac outcomes  Additional studies are necessary to determine appropriate use of LGE in decisions regarding intracardiac defibrillator (ICD) placement  LVOT obstruction with abnormal flow dynamics in some cases  Mitral valve regurgitation and systolic anterior motion (SAM) of mitral valve leaflet in some cases Echocardiographic Findings  Echocardiogram o Echocardiography is often diagnostic  Technical limitations (i.e., poor acoustic windows) can limit accuracy of assessment of wall thickness  Doppler flow analysis is gold standard for assessment of LVOT obstruction and mitral regurgitation Nuclear Medicine Findings  Radionuclide imaging with thallium or technetium may show reversible defects in absence of epicardial coronary artery disease Other Modality Findings  Cardiac CT o Excellent spatial resolution allows accurate assessment of LV wall thickness, particularly in patients with nondiagnostic echocardiogram and contraindication to MR Imaging Recommendations  Best imaging tool o Echocardiography  Widely available  Considered to be first-line modality o MR  Superior spatial resolution with excellent contrast between myocardium, blood, and adjacent structures  Particularly useful when echocardiography is technically limited or equivocal  Well suited for assessment of apical HCM &/or LV aneurysm 530

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Additional research is necessary to determine role of LGE in sudden cardiac death risk stratification

DIFFERENTIAL DIAGNOSIS Systemic Arterial Hypertension  Most common cause of concentric LV hypertrophy Athlete's Heart  Maximal wall thickness usually within modest range (13-15 mm) o With detraining, there can be regression of hypertrophy o Can be associated with LV, RV, and LA dilatation  Normal diastolic function Infiltrative Cardiomyopathy  Accumulation of abnormal metabolic products that lead to increased wall thickness and can progress to systolic and diastolic dysfunction P.7:10 

Increased LV wall thickness is most often concentric o Fabry disease: X-linked recessive disorder of glycosphingolipid metabolism  LGE is commonly seen in basal inferolateral wall o Hemochromatosis: Excessive deposition of iron  Abnormal T2* is indicative of iron overload o Amyloidosis: Deposition of fibrils, which can be derived from different proteins  LGE is most often diffuse, subendocardial, or circumferential, though other patterns are possible o Glycogen storage diseases Aortic Stenosis (AS)  Echocardiography is standard technique for diagnosis and follow-up of patients with AS  MR findings o Restricted aortic leaflet excursion with elevated transvalvular gradients o Associated LV hypertrophy is often concentric but can be asymmetric in certain cases PATHOLOGY General Features  Etiology o Caused by mutations in various genes encoding for proteins of sarcomere and associated structural myofilaments  Genetics o Autosomal dominant in most cases with incomplete penetrance and variable expressivity resulting in clinical heterogeneity among patients and family members  Genotype-positive/phenotype-negative or subclinical HCM patients require continued surveillance o Autosomal recessive, X-linked, and mitochondrial modes of inheritance are less common Staging, Grading, & Classification  HCM can be classified by presence or absence of LVOT obstruction Gross Pathologic & Surgical Features  Macroscopically characterized by LV hypertrophy o Can affect any segment of LV o RV involvement (typically mid to apical portion of RV) in ˜ 18% of cases Microscopic Features  Myocyte and myofibrillar disarray with “herringbone” or “pinwheel” configuration on microscopy  Myocyte hypertrophy  Increase in both interstitial fibrosis and replacement fibrosis  Dysplasia of small coronary arteries with smooth muscle cell proliferation CLINICAL ISSUES Presentation  Most common signs/symptoms o Most affected patients are asymptomatic o In patients with more severe disease, symptoms that may be associated with exertion include chest pain, dyspnea, syncope, and palpitations 531

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Other signs/symptoms o Abnormal ECG in 75-95% of patients with HCM Demographics  Age o Can present at any age from infancy to adulthood  Gender o No gender predominance  Epidemiology o Prevalence is 1 per 500 in general population Natural History & Prognosis  Most patients have benign course without any impact on longevity, but clinical manifestations can be significant in certain patients  Sudden cardiac death (SCD) o HCM is most common cause of SCD in young people and young athletes o Due to ventricular arrhythmias (ventricular tachycardia and ventricular fibrillation)  Congestive heart failure o Diastolic dysfunction is often an early finding o Systolic dysfunction can develop in small percentage of patients  Atrial fibrillation o Associated with heart failure o Increased risk of thromboembolism and stroke Treatment  Exercise restrictions to reduce risk of SCD  Calcium channel blockers or β-blockers can reduce risk of arrhythmias and improve symptoms associated with LVOT obstruction  Septal myomectomy or catheter-based alcohol septal ablation for symptomatic relief in patients with LVOT obstruction and favorable anatomy  Automatic ICD in patients at high risk for SCD SELECTED REFERENCES 1. Noureldin RA et al: The diagnosis of hypertrophic cardiomyopathy by cardiovascular magnetic resonance. J Cardiovasc Magn Reson. 14:17, 2012 2. Gersh BJ et al: 2011 ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 124(24):e783-831, 2011 3. Soler R et al: Magnetic resonance imaging of delayed enhancement in hypertrophic cardiomyopathy: relationship with left ventricular perfusion and contractile function. J Comput Assist Tomogr. 30(3):412-20, 2006 4. Hughes SE: The pathology of hypertrophic cardiomyopathy. Histopathology. 44(5):412-27, 2004 5. Moon JC et al: Toward clinical risk assessment in hypertrophic cardiomyopathy with gadolinium cardiovascular magnetic resonance. J Am Coll Cardiol. 41(9):1561-7, 2003 6. Braunwald E et al: Contemporary evaluation and management of hypertrophic cardiomyopathy. Circulation. 106(11):1312-6, 2002 7. Wilson JM et al: Magnetic resonance imaging of myocardial fibrosis in hypertrophic cardiomyopathy. Tex Heart Inst J. 29(3):176-80, 2002 P.7:11

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(Left) Steady-state free precession (SSFP) cine image in 4-chamber plane demonstrates HCM with severe asymmetric septal hypertrophy . (Right) Short-axis MR cine image demonstrates HCM with upper septal hypertrophy . The accurate measurement of the degree and extent of septal thickness in end diastole is important in the evaluation for potential treatments, such as alcohol septal ablation and septal myomectomy.

(Left) Four-chamber view MR cine image in diastole demonstrates symmetric thickening of the myocardium in the concentric variant of HCM. (Right) Vertical long-axis (2-chamber) MR cine image demonstrates the concentric variant of HCM. The differential diagnosis for concentric left ventricular hypertrophy includes hypertensive heart disease, aortic stenosis, athlete's heart, and infiltrative disorders such as amyloidosis and Anderson-Fabry disease.

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(Left) Cardiac CT in 2-chamber view demonstrates apical myocardial thickening with sparing of the basal myocardium, resulting in a spade-like configuration of the left ventricular cavity. (Right) Cardiac CT in 4-chamber view in diastole demonstrates the apical variant of HCM with a spade-like configuration of the left ventricular cavity. Cardiac CT can be considered in patients with a nondiagnostic echocardiogram and contraindications to cardiac MR. P.7:12

(Left) Short-axis MR cine image demonstrates hypertrophic cardiomyopathy with asymmetric upper septal left ventricular hypertrophy. (Right) Short-axis late gadolinium enhancement (LGE) image demonstrates the foci of LGE involving the anterior and posterior RV insertion sites which can be seen in HCM . Additional studies are necessary to determine if LGE should be considered an independent risk factor for sudden death in HCM and used in the assessment for intracardiac defibrillator therapy.

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(Left) Three-chamber view MR cine image demonstrates left ventricular hypertrophy involving the mid and apical segments of the left ventricle with an associated small apical aneurysm . The left ventricular outflow tract appears largely unobstructed. (Right) Three-chamber view late gadolinium enhancement image from the same patient demonstrates the same small left ventricular aneurysm at the apex.

(Left) Vertical long-axis (2-chamber) MR cine image in end diastole demonstrates left ventricular hypertrophy involving predominantly the mid and apical segments of the left ventricle. (Right) Vertical long-axis (2-chamber) late gadolinium enhancement image shows a patchy focus of late gadolinium enhancement involving the apical anterior segment , indicating myocardial fibrosis. P.7:13

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(Left) Graphic shows concentric HCM with systolic anterior motion (SAM) of the anterior mitral valve leaflet with resulting noncoaptation of the leaflets and mitral valve regurgitation . (Right) Three-chamber view coronary CTA shows hypertrophic obstructive cardiomyopathy with asymmetric septal hypertrophy resulting in narrowing of the left ventricular outflow tract and thus in flow acceleration, which in turn leads to SAM of the anterior mitral valve leaflet .

(Left) Three-chamber view MR cine image demonstrates HCM with significant asymmetric septal hypertrophy with systolic anterior motion of the mitral valve resulting in turbulent flow across the left ventricular outflow tract with an associated eccentric, posteriorly directed jet of mitral regurgitation . (Right) Three-chamber view on echocardiogram from the same patient demonstrates asymmetric septal hypertrophy with systolic anterior motion of the mitral valve .

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(Left) Three-chamber view on echocardiogram with color Doppler shows systolic anterior motion of the mitral valve with resulting turbulent flow across the left ventricular outflow tract (LVOT), consistent with LVOT obstruction , as well as an eccentric, posteriorly directed jet of mitral regurgitation . (Right) Vertical long-axis (2-chamber) MR cine image shows hypertrophic cardiomyopathy with midventricular hypertrophy associated with an apical aneurysm and left ventricular thrombus .

Ischemic Cardiomyopathy Key Facts Terminology  Left ventricular dilatation and impaired function resulting from coronary artery disease (CAD) o Hibernating myocardium that is ischemic but not infarcted may be contributory and is potentially reversible Imaging  Coronary CTA has high sensitivity (90-95%) for detection of hemodynamically significant stenosis  MR is gold standard for both functionality (cine MR) and viability (late gadolinium enhancement MR) assessments  Late gadolinium enhancement (LGE) MR can demonstrate presence, location, and size of infarction  Rule of thumb: If transmural extent of infarction in a given segment is < 50% on LGE MR, then functional recovery after revascularization is likely, and segment is considered viable  1st-pass perfusion MR (stress followed by rest) to detect coronary stenosis (85% sensitivity; 90% specificity)  PET has been regarded as gold standard for myocardial viability assessment, even though MR is considered superior by some  Technetium-99m: Sestamibi sensitivity of 80% and specificity of 66% for improvement post revascularization Top Differential Diagnoses  Dilated nonischemic cardiomyopathy  Chronic myocarditis  Infiltrative cardiomyopathy  Arrhythmogenic right ventricular dysplasia Clinical Issues  ˜ 70% of heart failure cases are caused by CAD

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(Left) Axial oblique maximum-intensity projection (MIP) image demonstrates multifocal coronary occlusions involving the left anterior descending (LAD) coronary artery as well as a large ramus branch . There is also extensive calcified plaque in the left circumflex coronary artery (LCX) . (Right) Volume-rendered image from a coronary CTA shows calcified plaque with occlusion of the LAD with collateral filling from the right coronary artery . Extensive calcified plaque is also noted in the LCX .

(Left) LGE (right) and 2-chamber (left) MR images of a patient with ischemic cardiomyopathy (ICM) show left ventricular (LV) cavity enlargement. LGE MR shows extensive hyperenhancement of the anterior wall and apex , signifying prior LAD territory infarction. The subendocardial predominance of the enhancement is typical of coronary artery disease (CAD). (Right) Echocardiogram 4-chamber view shows a dilated LV secondary to ICM and an echogenic mass in the LV apex (an apical thrombus). P.7:15

TERMINOLOGY Abbreviations  Ischemic cardiomyopathy (ICM) Definitions  Left ventricular (LV) dilatation and impaired function resulting from coronary artery disease (CAD)  Not all ischemic myocardial dysfunction is due to irreversible scarring o Hibernating myocardium that is ischemic but not infarcted may be contributory and is potentially reversible IMAGING General Features  Best diagnostic clue 538

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Dilated LV with poor systolic function showing areas of delayed enhancement in CAD pattern (wavefront from subendocardial to epicardial) on MR imaging  Morphology o Dilated LV cavity with apparent wall thinning o Areas of infarction may undergo fatty replacement Radiographic Findings  Radiography o Enlarged cardiac silhouette, often globular in shape o May reveal evidence of heart failure  Kerley B lines, interstitial edema, and vascular redistribution to upper lobes CT Findings  NECT o Areas of fatty replacement or calcification signifying prior ischemic injury may be evident  CTA o Coronary CTA has high sensitivity (90-95%) for detection of hemodynamically significant stenosis  Delayed scan (5 minutes after initial contrast bolus) may allow detection of myocardial infarction o Cine multiplanar reformats allow assessment of global and regional function MR Findings  Steady-state free precession (SSFP) cine sequence to assess LV global and regional wall motion o Stack of contiguous short-axis images obtained from mitral valve ring to apex  Allows measurement of ventricular volumes and ejection fraction (gold standard)  T2W MR may appear bright in regions of acute irreversible myocardial infarction o Can appear dark when myocardial hemorrhage is present  Late gadolinium enhancement (LGE) MR can demonstrate presence, location, and size of infarction o Gradient-echo inversion recovery sequence is reference standard  Single-shot SSFP version (accuracy ˜ 95%) may be substituted in arrhythmic or uncooperative patients o Images are obtained 8-10 minutes after bolus of 0.15 mmol/kg gadolinium o Inversion time is adjusted to maximize nulling of normal myocardium (appears black) o Scar appears bright (hyperenhanced) o Likelihood of functional recovery following revascularization depends on degree of transmurality of scar  Rule of thumb: If transmural extent of infarction in a given segment is < 50%, then functional recovery after revascularization is likely, and segment is considered viable  1st-pass perfusion MR (stress followed by rest) to detect coronary stenosis (85-90% sensitivity/specificity) o Vasodilation induced by regadenoson or adenosine (adenosine dose: 140 µg/kg/min for 3 minutes) o Perfusion imaging performed using T1-weighted (GRE or hybrid EPI-GRE) sequences during passage of 0.1 mmol gadolinium through myocardium  Short-axis stack (typically 4 slices/beat or 8 slices each obtained at every other beat) o Repeat sequence 10 minutes later for rest perfusion images  Useful to exclude artifacts, which will appear similar on stress and rest images Echocardiographic Findings  Echocardiogram o Echo shows segment akinesis acutely, segment thinning and dysfunction chronically o Chronic infarction appears bright, indicating fatty replacement o Stress echo  Low-dose dobutamine (5-10 µg/kg/min)  Increased contractility in viable but dysfunctional myocardial segments (contractile reserve)  Sensitivity of 82% and specificity of 79% for improvement in regional wall contractility post revascularization Angiographic Findings  Coronary angiography usually reveals multiple stenoses and occlusions in several territories  Ventricular angiography usually reveals reduced wall motion, ejection fraction, and wall thickening Nuclear Medicine Findings  PET o PET has been regarded as gold standard for myocardial viability assessment, even though MR is considered superior by some (mostly MR specialists)  Validated for viability and subsequent prognosis 539

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Qualitative assessment of regional myocardial blood flow  Most commonly used tracers are rubidium-82 and N-13 ammonia  Performed under rest and stress conditions  Good diagnostic accuracy (sensitivity and specificity between 85 and 95%) o Metabolic evaluation of myocardium  Ischemia results in impaired fatty acid and increased glucose metabolism  Most commonly used tracer is 5-fluorodeoxyglucose (FDG) Technetium-99m: Sestamibi uptake dependent on perfusion, cell membrane integrity, and mitochondrial function o Dysfunctional segments with > 50-60% uptake are considered viable P.7:16

o Sensitivity of 81% and specificity of 66% for improvement post revascularization Thallium scan o Initial uptake is determined by blood flow o Subsequent uptake depends on cell membrane integrity/viability o 2 protocols  Stress-redistribution-reinjection: Assesses for stress-inducible ischemia and viability  Rest-redistribution: Assesses viability o Dysfunctional but viable segments are considered when tracer uptake increases > 10% or when activity > 50-60% o Sensitivity of 86% and specificity of 59% for improvement in regional wall contractility post revascularization Imaging Recommendations  Best imaging tool o Currently, PET is considered gold standard, but evolving evidence shows that cardiac MR may be superior  Major advantage of LGE MR is that it provides visualization of both alive and dead myocardium  LGE MR is especially useful in setting of small subendocardial myocardial infarction  Only LGE MR can accurately assess thinned but viable hibernating myocardium DIFFERENTIAL DIAGNOSIS Dilated Nonischemic Cardiomyopathy (DNICM)  Often diagnosis of exclusion (no CAD)  LGE MR will show either no uptake (60%) or a non-CAD midwall pattern (28%) Chronic Myocarditis  Phenotypically resembles DNICM and may be responsible for some cases of DNICM  Postviral etiology is often presumed Infiltrative Cardiomyopathy  Sarcoid, Chagas disease, and hemochromatosis may produce dilated cardiomyopathy o MR often shows differentiating features Arrhythmogenic Right Ventricular Dysplasia  LV is involved in 15% of patients PATHOLOGY General Features  After acute coronary artery thrombosis with transmural infarct, LV undergoes process of remodeling  At cellular level, destruction of connective tissue and slippage of myofibrils are seen  At tissue/organ level, dilatation in size and shape of ventricle is noted Staging, Grading, & Classification  ICM may be the result of scarring from prior infarction o However, it may be due to myocardial hibernation, which is reversible  Refers to downregulation of function in response to chronic ischemia CLINICAL ISSUES Presentation  Most common signs/symptoms o Dyspnea on exertion, shortness of breath, and other heart failure symptoms  Chest pain: Substernal, pressing, occasionally radiating to left arm 

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Diagnostic Imaging Cardiovascular o Development of ICM may be preceded by symptomatic or silent infarcts  Symptoms associated with arrhythmias Demographics  Age o Parallel demographics of CAD  Epidemiology o ˜ 70% of heart failure cases are caused by CAD Natural History & Prognosis  Ischemic heart failure is associated with shorter survival than nonischemic heart failure  More extensive CAD is associated with shorter survival Treatment  Poor prognosis for 5-year survival o Depends on ejection fraction, New York Heart Association class, arrhythmias  Therapy for acute myocardial infarction can preserve tissue and alter progression of disease  Medical therapy o Diuretics o ACE inhibitors or angiotensin (AT1) blockers o β-blockers in all euvolemic patients without recent symptomatic heart failure or requirement for βagonists o Aspirin: Reduces risk of coronary thrombosis o Cholesterol-lowering therapy  Coronary revascularization (bypass surgery) can improve prognosis o Most reliable in patients with angina o Best data in patients with viable myocardium o Surgical risk is high; however, these patients derive greatest benefit  Implantable defibrillator o Latest data support implantation in patients with  Inducible or spontaneous arrhythmias  Ejection fraction < 30% with ischemic etiology  Transplantation  LV assist device placement SELECTED REFERENCES 1. Shah DJ et al: Prevalence of regional myocardial thinning and relationship with myocardial scarring in patients with coronary artery disease. JAMA. 309(9):909-18, 2013 2. Schuster A et al: Imaging in the management of ischemic cardiomyopathy: special focus on magnetic resonance. J Am Coll Cardiol. 59(4):359-70, 2012 3. Klem I et al: Improved detection of coronary artery disease by stress perfusion cardiovascular magnetic resonance with the use of delayed enhancement infarction imaging. J Am Coll Cardiol. 47(8):1630-8, 2006 4. Schinkel AF et al: Prognostic role of dobutamine stress echocardiography in myocardial viability. Curr Opin Cardiol. 21(5):443-9, 2006 P.7:17

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(Left) Two-chamber cine (left) and LGE (right) MR images demonstrate a dilated LV with prior anterior wall infarction (bright region ). There is also a tiny dark adherent thrombus . LGE MR is significantly more sensitive than echocardiography for the detection of ventricular thrombi. (Right) Four-chamber cine (left) and LGE (right) MR images show a dilated LV with enhancement on LGE MR. Little viability is seen in the apex , but the lateral wall shows residual viable myocardium .

(Left) Two-chamber cine (left) and LGE (right) MR images of a patient with reversible ICM show a thinned anterior wall that remains viable. Even though the anterior wall measured < 5.5 mm, there was no enhancement on LGE MR, indicating hibernating myocardium with preserved viability. (Right) Two-chamber cine diastolic (left) and systolic (right) images of this patient with reversible ICM demonstrate profound recovery of function and wall thickness following revascularization.

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(Left) Four-chamber view LGE MR of a patient with dilated nonischemic cardiomyopathy (DNICM) shows only focal linear midwall enhancement and no subendocardial enhancement. This pattern, seen in ˜ 28% of patients with DNICM, is clearly different from the usual (subendocardial predominant) CAD pattern. (Right) Four-chamber view LGE MR of a patient with nonischemic cardiomyopathy due to sarcoidosis shows patchy abnormal enhancement in a non-CAD pattern.

Nonischemic Dilated Cardiomyopathy Key Facts Terminology  Left ventricular (LV) dilation with systolic dysfunction ± right ventricular (RV) dilation/dysfunction Imaging  MR is gold standard for ventricular volumes and quantitative function o Ventricular dilatation (indexed to body surface area) o Midwall septal pattern of late gadolinium enhancement (LGE) can be seen in idiopathic dilated cardiomyopathy (present in ˜ 30%) o Epicardial or mid-myocardial LGE may suggest etiologies such as sarcoid, myocarditis, Chagas disease o Presence of LGE is associated with increased risk of major adverse cardiac events o Patterns of LGE may suggest specific etiology o Apical LV thrombus can be seen with severe LV dysfunction  Echocardiography remains initial test in evaluation of suspected cardiomyopathy o Gold standard for assessment of valvular heart disease  Cardiac CTA can exclude obstructive coronary artery disease Clinical Issues  Many patients may be asymptomatic  Severity of LV dilation/dysfunction and concomitant RV dilation/dysfunction are associated with prognosis  ˜ 25% of patients may have improvement in LV function over time  Standard medical therapy for heart failure  Device therapy with implantable cardioverter defibrillator ± biventricular pacing

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(Left) Four-chamber view MR cine (SSFP) shows left ventricular (LV) dilatation and severe systolic dysfunction. Cardiac MR is the gold standard for the assessment of LV volumes and quantitative ventricular function. Steady-state free precession images allow for excellent tissue contrast. (Right) Vertical long-axis (2-chamber) cardiac CT shows LV dilatation with severe systolic dysfunction. Like cardiac MR, a contrast-enhanced CT provides excellent tissue contrast.

(Left) AP radiograph shows cardiomegaly, low lung volumes, and prominent pulmonary vasculature. AP technique can magnify cardiac silhouette. (Right) 3D echocardiogram shows LV dilatation and severe systolic dysfunction. 3D echocardiography can improve the accuracy of LV volume and ejection fraction measurement by avoiding the geometric modeling necessary in 2D techniques. In some cases, definition of the endocardial border can be limited due to low spatial resolution. P.7:19

TERMINOLOGY Abbreviations  Dilated cardiomyopathy (DCM) Synonyms  Idiopathic dilated cardiomyopathy Definitions  Left ventricular (LV) chamber dilation with systolic dysfunction ± right ventricular (RV) dilation/dysfunction o LV dilatation is assessed by LV diameter (2D echocardiography) or quantitative LV volumes (cardiac MR [CMR], 3D echo, MUGA) o Systolic dysfunction (LV ejection fraction [EF] < 55%)  Multiple possible etiologies o Idiopathic 544

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Familial (genetic) Infectious Toxic (e.g., alcohol, cocaine) Metabolic (e.g., hypophosphatemia, hypocalcemia, uremia) Myocarditis Infiltrative disease (e.g., hemochromatosis, sarcoid) Peripartum cardiomyopathy Connective tissue disease Chemotherapy (e.g., doxorubicin) Endocrinopathies (e.g., thyroid dysfunction, pheochromocytoma, Cushing disease) Current definition excludes ischemic, hypertensive, and valvular heart disease

IMAGING General Features  Best diagnostic clue o Cardiomegaly Radiographic Findings  Radiography o Cardiomegaly with cardiac silhouette > 50% of thoracic diameter on posteroanterior view o Atrial enlargement o Findings of decompensated congestive heart failure (pulmonary edema, pleural effusion) CT Findings  Cardiac CTA can exclude obstructive coronary artery disease  Volume-rendered multiphase data sets can accurately quantify ventricular volumes, mass, and EF MR Findings  MR cine o Ventricular dilatation (indexed to body surface area) o Decreased systolic function with global or regional myocardial dysfunction o Gold standard for ventricular volumes and quantitative function o Apical LV thrombus can be seen with severe LV dysfunction  Perfusion o Stress perfusion without evidence of ischemia  Late gadolinium enhancement (LGE) o Midwall septal pattern of LGE can be seen in idiopathic DCM (present in ˜ 30%) o Epicardial or mid-myocardial LGE may suggest etiologies such as sarcoid, myocarditis, Chagas disease o Presence of LGE is associated with increased risk of major adverse cardiac events o LGE images may be normal despite presence of diffuse fibrosis; novel T1 mapping techniques may help characterize degree of diffuse fibrosis Echocardiographic Findings  LV dysfunction/dilation ± RV involvement o Systolic and diastolic dysfunction can be evaluated  2D echocardiography o LV wall thickness may be increased o LVEF reduced by qualitative or semiquantitative measures (modified Simpson method)  Doppler echocardiography o Gold standard for assessment of valvular heart disease o Comprehensive exam including conventional Doppler of mitral valve inflow and tissue Doppler of LV myocardium can estimate cardiac filling pressures (i.e., pulmonary capillary wedge pressure)  Easily accessible and relatively inexpensive Angiographic Findings  Gold standard for evaluation of coronary artery disease  Dilated left ventricle with reduced systolic function on left ventriculogram Nuclear Medicine Findings  PET o Can exclude prior infarct or ischemia as etiology of LV dysfunction  Radionuclide ventriculography o Quantitative ventricular function; now largely replaced by echocardiography Imaging Recommendations 545

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Best imaging tool o MR is most accurate method for assessing LV volumes, mass, and ejection fraction  Patterns of LGE may suggest specific etiology  Ongoing studies will determine comparative effectiveness of MR in management of cardiomyopathy o Echocardiography remains initial test in evaluation of suspected cardiomyopathy  In some patients, limited acoustic windows may reduce diagnostic accuracy  Protocol advice o Echocardiography is most common initial test in evaluation of suspected cardiomyopathy o Cardiac MR and CT should be considered based on patient-specific parameters DIFFERENTIAL DIAGNOSIS Restrictive Cardiomyopathy  Increased resistance to ventricular filling due to abnormal myocardial stiffness  Biatrial enlargement with normal ventricular size  Diastolic dysfunction  Chest radiography findings of congestive heart failure without cardiomegaly P.7:20

Hypertrophic Cardiomyopathy  Genetic disease of cardiac sarcomere  Hypertrophy tends to be asymmetric involving basal interventricular septum, but disease may manifest with atypical patterns of hypertrophy (e.g., mid cavity or apical) Valvular Heart Disease  Chronic mitral regurgitation and aortic regurgitation can lead to LV dilatation and systolic dysfunction o Echocardiography is imaging test of choice for evaluation of valvular heart disease o Cardiac MR can be useful in patients with limited or inconclusive echo data; phase-contrast imaging can be used to calculate regurgitant volumes  Severe aortic stenosis o Longstanding severe LV pressure overload can cause LV systolic dysfunction and chamber dilatation  If cardiac output is low, transaortic gradients may be low (“low-gradient aortic stenosis”) PATHOLOGY General Features  Etiology o Multiple possible causes  Common causes include viral infections as well as genetic mutations o In many cases, specific etiology is not identified though thorough evaluation for potentially reversible causes is warranted  Genetics o Familial DCM is estimated to account for ˜ 25% of idiopathic cases  Mode of inheritance is usually autosomal dominant although cases of autosomal recessive, X-linked, and mitochondrial inheritance have been described o Inherited syndromes  DCM may be important component of inherited disorders such as neuromuscular disease (i.e., muscular dystrophies) Staging, Grading, & Classification  New York Heart Association (NYHA) criteria is most often used to assess functional class of patients with heart failure and is associated with prognosis Gross Pathologic & Surgical Features  LV dilation, which may be associated with RV dilation o Associated biatrial enlargement may also be seen  Thrombi, particularly in LV apex, may be seen Microscopic Features  Interstitial and perivascular fibrosis  Variation in myocyte size CLINICAL ISSUES Presentation  Most common signs/symptoms 546

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Dyspnea with exertion, impaired exercise capacity, orthopnea, paroxysmal nocturnal dyspnea, and peripheral edema  Other signs/symptoms o Arrhythmia, conduction disturbance, thromboembolic complications Demographics  Age o Risk for morbidity and mortality with older age  Gender o M>F  Ethnicity o African Americans have almost 3x greater risk for developing DCM, which is not fully attributed to differences in risk factors such as hypertension, tobacco use, and EtOH consumption  Epidemiology o Prevalence of 36 per 100,000; may be underestimate since patients may have subclinical cardiomyopathy o Increased prevalence and worse prognosis in men and African Americans o 25% of DCM may be genetic in etiology Natural History & Prognosis  Many patients may be asymptomatic  In those who develop symptomatic congestive heart failure, annual mortality rate is ˜ 10%  ˜ 25% of patients may have improvement in LV function over time  Severity of LV dilation/dysfunction and concomitant RV dilation/dysfunction are associated with prognosis  Presence of LGE is associated with worse prognosis  Impaired capacity on cardiopulmonary exercise testing is associated with worse prognosis and is used in evaluation for cardiac transplantation Treatment  Standard medical therapy for heart failure o ACE inhibitors, β-blockers, aldosterone receptor blockers, diuretics, digoxin  Anticoagulation to reduce risk of thromboembolism in patients with atrial fibrillation  Device therapy with implantable cardioverter defibrillator ± biventricular pacing  Cardiac transplantation DIAGNOSTIC CHECKLIST Consider  Ischemic etiology should be excluded Image Interpretation Pearls  CMR provides most detailed tissue characterization  LGE patterns can help identify specific etiology SELECTED REFERENCES 1. Ismail TF et al: Prognostic importance of late gadolinium enhancement cardiovascular magnetic resonance in cardiomyopathy. Heart. 98(6):438-42, 2012 2. Gottlieb I et al: Magnetic resonance imaging in the evaluation of non-ischemic cardiomyopathies: current applications and future perspectives. Heart Fail Rev. 11(4):313-23, 2006 3. Rochitte CE et al: The emerging role of MRI in the diagnosis and management of cardiomyopathies. Curr Cardiol Rep. 8(1):44-52, 2006 4. Abbara S et al: Pericardial and myocardial disease. In Miller SW: Cardiac Imaging: The Requisites. 2nd ed. Philadelphia: Mosby. 270-2, 2005 P.7:21

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(Left) Short-axis late gadolinium enhancement (LGE) shows a linear focus of LGE in a midwall distribution involving the mid anteroseptum and mid inferoseptum . This pattern of LGE is typical of a nonischemic dilated cardiomyopathy. (Right) Four-chamber view LGE image shows a linear focus of LGE involving the basal to mid septum in a midmyocardial distribution and a dilated LV cavity in a patient with nonischemic dilated cardiomyopathy.

(Left) Short-axis LGE image shows diffuse LGE involving the mid anterior and inferior septum in an epicardial distribution as well as patchy subendocardial LGE of the lateral segments . (Right) Four-chamber view LGE image from the same patient shows diffuse LGE involving the basal to apical septum and lateral walls . RV endomyocardial biopsy showed nonspecific fibrosis with no evidence of myocarditis or sarcoidosis.

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(Left) Curved MPR coronary CTA of the left main artery and left anterior descending artery shows no evidence of coronary artery disease in a patient presenting with a new-onset dilated cardiomyopathy. (Right) Four-chamber view cardiac CT image during diastole shows LV dilation in the same patient with a cardiomyopathy. There is no evidence of wall thinning or calcification to suggest a prior infarct, and there is no evidence of LV thrombus. All these findings point to a nonischemic etiology.

Restrictive Cardiomyopathy Key Facts Terminology  Abnormal diastolic function with normal ventricular cavity size and relatively preserved systolic function  Etiologies o Noninfiltrative conditions, including idiopathic, familial, hypertrophic cardiomyopathy, scleroderma, and diabetic cardiomyopathy o Infiltrative conditions, such as amyloidosis, sarcoidosis, and glycogen storage disease o Myocardial diseases, such as hypereosinophilic syndrome, carcinoid, drugs effects, and radiation Imaging  Chest x-ray demonstrates typical appearance of congestive heart failure without significant cardiomegaly  Echocardiography may show increased left ventricular wall thickness o Increased filling pressures or restrictive filling pattern on pulsed wave Doppler of the mitral valve o Echocardiography alone is often insufficient, particularly when evaluating for specific etiologies  MR is most comprehensive imaging modality for assessment of cardiomyopathy o Patterns of late gadolinium enhancement can be diagnostic for specific etiologies of restrictive cardiomyopathy Top Differential Diagnoses  Constrictive pericarditis  Hypertensive heart disease Diagnostic Checklist  If echocardiogram suggests restrictive cardiomyopathy, consider cardiac MR to evaluate for specific etiologies, which can have implications for treatment

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(Left) Four-chamber view on echocardiogram shows biventricular hypertrophy, biatrial enlargement, and preserved systolic function, consistent with restrictive cardiomyopathy. (Right) Pulsed wave spectral Doppler at the level of mitral annulus from the same patient confirms a restrictive filling pattern with a prominent E wave (increased early atrial diastolic filling) and reduced A wave (late atrial filling from atrial systole). Cardiac MR was performed for further evaluation.

(Left) Four-chamber MR cine (SSFP) shows biventricular hypertrophy, severe biatrial enlargement, and nearly complete cavity obliteration of the mid to apical left ventricle, indicative of hyperdynamic systolic function. (Right) Short-axis late gadolinium enhancement (LGE) image from the same patient shows 2 foci of abnormal LGE involving the anterior and posterior right ventricular insertion sites , typical of hypertrophic cardiomyopathy, which should be considered in the differential for restrictive cardiomyopathy. P.7:23

TERMINOLOGY Definitions  Abnormal diastolic function with relatively preserved systolic function o Normal ventricular cavity size o Abnormal ventricular compliance that leads to elevated filling pressures o Hemodynamics can resemble constrictive pericarditis IMAGING General Features  Best diagnostic clue o Congestive heart failure with normal ventricular cavity size 550

Diagnostic Imaging Cardiovascular o Increased filling pressures or restrictive filling pattern on Doppler echocardiography Location o Left ventricle (LV) &/or right ventricle (RV)  Size o Possible increase in ventricular wall thickness o Biatrial enlargement  Morphology o Depending on etiology, can be associated with increased cardiac mass Radiographic Findings  Radiography o Chest x-ray demonstrates findings of congestive heart failure without significant cardiomegaly  Pulmonary venous congestion  Pleural effusions  May demonstrate biatrial enlargement CT Findings  Cardiac CT angiography can accurately depict and quantify ventricular and atrial cavity sizes as well as ventricular wall thickness o Useful when evaluating for concomitant coronary artery disease and specific etiologies, such as constrictive pericarditis MR Findings  Most accurate imaging modality to assess ventricular morphology, function, and tissue characteristics o Primary restrictive cardiomyopathies are associated with small to normal ventricular cavity size with normal systolic function o Patterns of late gadolinium enhancement (LGE) can be diagnostic for specific etiologies  Amyloidosis typically has diffuse, circumferential, subendocardial pattern of LGE with abnormal gadolinium kinetics in blood pool  Hypertrophic cardiomyopathy can be associated with LGE at RV insertion sites and with patchy LGE in areas of maximal wall thickness  Sarcoidosis can be associated with diffuse LGE in various distributions involving RV and LV  Hypereosinophilic syndromes can be associated with circumferential, subendocardial pattern of LGE, which typically involves mid to apical segments and may be associated with LV thrombus  Can evaluate for pericardial constriction using comprehensive protocol o Pericardial thickness o LGE o Myocardial adhesions o Morphologic evidence of interventricular interdependence Echocardiographic Findings  Echocardiogram o Normal LV cavity size and normal systolic function o Abnormal diastolic function  Mitral inflow Doppler pattern assesses ventricular compliance and filling pressures by comparing early (E) and late (A) diastolic filling  Tissue Doppler pattern assesses myocardial motion during early (E') and late (A') diastolic filling o Biatrial enlargement Imaging Recommendations  Best imaging tool o MR is most comprehensive imaging modality for assessment of cardiomyopathy  Accurately depicts atrial and ventricular morphology  LGE is most sensitive method for identifying scar and fibrosis  High sensitivity (88%), specificity (100%), and predictive accuracy (93%) in differentiating restrictive cardiomyopathy from constrictive pericarditis o Echocardiography alone is often insufficient, particularly when evaluating for specific etiologies  Doppler echo parameters are most reliable noninvasive methods for assessing filling patterns  Protocol advice o Steady-state free precession (SSFP) cine images for ventricular morphology and function 

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LGE to assess for myocardial and pericardial patterns of fibrosis or injury may suggest specific etiology DIFFERENTIAL DIAGNOSIS Constrictive Pericarditis  Significant respiratory variation in transvalvular Doppler filling patterns on echocardiogram, consistent with interventricular interdependence  Pericardial thickening (> 3 mm) on MR or CT  Pericardial adhesions via myocardial tagging on MR o Tag lines bend but do not break, which is indicative of epicardial-pericardial adhesion Hypertensive Heart Disease  Concentric LV hypertrophy in setting of hypertension  Minimal to no LGE  Can be associated with elevated filling pressures and diastolic dysfunction PATHOLOGY General Features  Etiology o Primary idiopathic restrictive cardiomyopathy is uncommon and has no identifiable cause o Familial restrictive cardiomyopathy is also rare entity with autosomal dominant transmission P.7:24

o

Secondary restrictive cardiomyopathy is most common etiology  Infiltrative processes  Amyloidosis  Sarcoidosis  Hemochromatosis  Glycogen storage disorders  Noninfiltrative conditions  Scleroderma  Diabetes  Hypertrophic cardiomyopathy  Myocardial diseases  Hypereosinophilic endomyocardial fibrosis  Carcinoid heart disease  Radiation-associated myocardial fibrosis  Chemotherapy-mediated cardiotoxicity Staging, Grading, & Classification  New York Heart Association (NYHA) functional classification of heart failure Gross Pathologic & Surgical Features  Increased LV mass and wall thickness  Biatrial enlargement Microscopic Features  Depend on whether specific etiology is identified o Diffuse infiltration of amyloid protein in amyloidosis o Noncaseating granulomas in sarcoidosis o Extensive iron deposits in hemochromatosis o Myocyte hypertrophy/fibrosis in endomyocardial fibrosis CLINICAL ISSUES Presentation  Most common signs/symptoms o Shortness of breath and exercise intolerance  Other signs/symptoms o Paroxysmal nocturnal dyspnea, orthopnea, edema o Fatigue, generalized weakness, cachexia  Clinical profile o Physical exam is consistent with pulmonary and systemic congestion  Pulmonary edema  Increased central venous pressure (e.g., jugular venous distension, peripheral edema, hepatomegaly, ascites) 552

Diagnostic Imaging Cardiovascular Demographics  Age o Increased incidence in elderly but depends on specific etiology  Gender o F>M  Ethnicity o Depends on specific etiology Natural History & Prognosis  Historically associated with poor prognosis, but this depends on whether underlying etiology is identified Treatment  Improve symptoms by lowering elevated filling pressures without significantly reducing cardiac output o Diuretics and nitrates for preload reduction o β-blockers &/or calcium channel blockers may improve diastolic function and reduce afterload in cases of concomitant hypertension  Medical treatment of underlying systemic disorder o Immune-modulating therapy for sarcoidosis o Chemotherapy and stem cell transplant for amyloidosis o Phlebotomy and chelation therapy for hemochromatosis  Pacemaker for high-grade atrioventricular block or sick sinus syndrome is associated with atrial fibrillation  Implantable cardioverter-defibrillator (ICD) for secondary prevention in patients with sustained ventricular arrhythmias  Cardiac transplantation in medical refractory cases DIAGNOSTIC CHECKLIST Image Interpretation Pearls  Echocardiogram can show increased LV wall thickness and normal cavity size, with evidence of increased filling pressures on Doppler  If echocardiogram suggests restrictive cardiomyopathy, consider cardiac MR to evaluate for specific etiologies, which can have implications for treatment SELECTED REFERENCES 1. Gupta A et al: Cardiac MRI in restrictive cardiomyopathy. Clin Radiol. 67(2):95-105, 2012 2. Quarta G et al: Cardiomyopathies: focus on cardiovascular magnetic resonance. Br J Radiol. 84 Spec No 3:S296-305, 2011 3. Rochitte CE et al: The emerging role of MRI in the diagnosis and management of cardiomyopathies. Curr Cardiol Rep. 8(1):44-52, 2006 4. Cury RC et al: Images in cardiovascular medicine. Visualization of endomyocardial fibrosis by delayed-enhancement magnetic resonance imaging. Circulation. 111(9):e115-7, 2005 5. Chinnaiyan KM et al: Constrictive pericarditis versus restrictive cardiomyopathy: challenges in diagnosis and management. Cardiol Rev. 12(6):314-20, 2004 6. Wald DS et al: Restrictive cardiomyopathy in systemic amyloidosis. QJM. 96(5):380-2, 2003 7. Friedrich MG: Cardiovascular magnetic resonance in cardiomyopathies. In Manning WJ et al: Cardiovascular Magnetic Resonance. Philadelphia: Churchill Livingstone. 415-8, 2002 8. Ammash NM et al: Clinical profile and outcome of idiopathic restrictive cardiomyopathy. Circulation. 101(21):24906, 2000 9. Berensztein CS et al: Usefulness of echocardiography and doppler echocardiography in endomyocardial fibrosis. J Am Soc Echocardiogr. 13(5):385-92, 2000 10. Myers RB et al: Constrictive pericarditis: clinical and pathophysiologic characteristics. Am Heart J. 138(2 Pt 1):21932, 1999 11. Angelini A et al: Morphologic spectrum of primary restrictive cardiomyopathy. Am J Cardiol. 80(8):1046-50, 1997 12. Kushwaha SS et al: Restrictive cardiomyopathy. N Engl J Med. 336(4):267-76, 1997 13. Leung DY et al: Restrictive cardiomyopathy: diagnosis and prognostic implications. In Otto CM: The Practice of Clinical Echocardiography. Philadelphia: W. B. Saunders. 473-94, 1997 14. Benotti JR et al: Clinical profile of restrictive cardiomyopathy. Circulation. 61(6):1206-12, 1980 P.7:25

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(Left) Four-chamber view on echocardiogram shows increased biventricular wall thickness with a speckled pattern suggestive of amyloidosis, which should be considered in the differential for restrictive cardiomyopathy. (Right) Four-chamber view MR cine from the same patient shows increased biventricular wall thickness and biatrial enlargement, consistent with restrictive cardiomyopathy. Note the increased atrial wall and interatrial septal thickness, which can be seen with amyloidosis .

(Left) Short-axis MR cine shows increased biventricular wall thickness with preserved systolic function. (Right) Shortaxis LGE image shows a diffuse pattern of LGE involving the septum, inferolateral wall, and anterolateral papillary muscle, as well as the free wall of the right ventricle . In the setting of biventricular increase in wall thickness, this extent of LGE is consistent with amyloidosis. In this patient, a right ventricular endomyocardial biopsy confirmed cardiac amyloidosis.

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(Left) Four-chamber view on MR shows tubular left and right ventricles with biatrial enlargement in a patient presenting with heart failure. (Right) Short-axis T1-weighted fast spin-echo MR in the same patient shows a significant increase in pericardial thickness , measuring up to 9 mm. Taken together with tubular ventricles and biatrial enlargement, these findings are consistent with constrictive pericarditis, which should be considered in the differential for restrictive cardiomyopathy.

Myocarditis Key Facts Terminology  Inflammatory involvement of the myocardium with necrosis &/or degeneration of adjacent myocytes Imaging  Lake Louise consensus criteria: Study is consistent with myocarditis if 2 of the following 3 MR criteria are positive o T2 myocardial to skeletal muscle signal ratio > 1.9 o T1 C+ myocardial global relative enhancement > 4.0 o Delayed enhancement in subepicardial or transmural pattern  New dilated cardiomyopathy in otherwise healthy person shortly after viral syndrome Pathology  Infectious viral etiologies are most frequent Clinical Issues  Variable clinical presentation from subclinical to acute heart failure with hemodynamic compromise Diagnostic Checklist  Cardiac MR study should be performed if patient is symptomatic with clinical suspicion for myocarditis (i.e., chest pain, elevated troponin, normal coronary arteries, and suspected viral etiology)  MR report should include o LV volume and function o Presence or absence of markers of inflammatory activity and injury (T2 ratio, T1 global relative enhancement, late gadolinium enhancement) o Presence or absence of pericardial effusion  Repeat cardiac MR 1-2 weeks after initial study if no positive criteria are present but onset of symptoms is recent and there is strong suspicion for myocarditis

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(Left) Axial T1 pre-contrast image at mid left ventricular (LV) level with oblique saturation band over the atria to reduce flow-related phase encoding artefact is obtained for baseline signal intensity measurement. (Right) Axial T1 post-contrast image demonstrates patchy early enhancement in the lateral LV wall , consistent with hyperemia due to myocarditis. This pattern is less typical; usually there is global T1 signal increase, which can be visually inapparent and needs to be quantified.

(Left) Double-inversion T2 left ventricular short-axis image at basal level demonstrates increased signal in the inferolateral left ventricular wall, consistent with edema . (Right) Short-axis LGE MR demonstrates typical subepicardial late gadolinium enhancement involving the lateral, inferior, inferoseptal, and anteroseptal left ventricular walls . P.7:27

TERMINOLOGY Definitions  Inflammatory involvement of the myocardium with necrosis &/or degeneration of adjacent myocytes IMAGING General Features  Best diagnostic clue o Lake Louise consensus criteria: Study is consistent with myocarditis if 2 of the following 3 MR criteria are positive  T2WI increased myocardial to skeletal muscle (SM) signal ratio  T1WI C+ increased myocardial global relative enhancement (GRE)  Delayed enhancement in subepicardial or transmural pattern 556

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New dilated cardiomyopathy in otherwise healthy person shortly after viral syndrome  Normal coronary arteries despite enzyme leak and ECG changes o Perimyocarditis Radiographic Findings  Radiography o Pulmonary edema in cases of acute myocarditis CT Findings  Cardiac gated CTA o Normal coronary arteries helps exclude ischemic injury as etiology o Global hypokinesis on multiphase cine reconstructions possibly with LV dilatation o Quantifies degree of depressed cardiac function o Preliminary research shows reasonable correlation of MDCT delayed enhancement with MR for detection of myocarditis MR Findings  T2WI o Increased due to inflammation-related edema o May be regional or global  Global involvement may not be visually appreciated, requiring measurement of LV signal intensity o T2 signal ratio > 1.9 is consistent with myocarditis  T2 ratio = ROI LV myocardium/ROI skeletal muscle  ROI = region of interest  Can be inaccurate in patients with abnormal skeletal muscle (i.e., myositis) o Triple inversion recovery: Best contrast o Double inversion recovery: Better signal to noise ratio o In absence of abnormal delayed enhancement, increased T2 is consistent with reversible myocardial injury o Pericardial inflammation  T1WI C+ o Focal or diffuse enhancement due to myocardial hyperemia  Early tends to be focal  Late tends to be diffuse o GRE ratio > 4.0 is consistent with myocarditis  GRE ratio measures LV myocardial enhancement relative to skeletal muscle enhancement  GRE = ([post-contrast LV - pre-contrast LV]/pre-contrast LV)/([post-contrast SM pre-contrast SM]/pre-contrast SM)  Normal GRE is < 2.5  Can be inaccurate in patients with abnormal skeletal muscle (i.e., myositis)  SSFP cine o Global LV systolic dysfunction  Sometimes localized to inferolateral LV wall o Quantify LV volume, ejection fraction, and end-diastolic LV wall thickness  Can see transient increase in end-diastolic LV wall thickness o ± pericardial effusion o Excellent for assessing recovery of function  Late gadolinium enhancement (LGE) o Consistent with irreversible myocardial injury o Typical pattern is subepicardial or transmural o Sometimes midwall hyperenhancement (noncoronary distribution) o May be diffuse in cases of severe myocarditis o Best independent predictor of sudden cardiac death o Pericardial late gadolinium enhancement, indicating inflammation Echocardiographic Findings  Echocardiogram o Normal in less severe cases o Demonstrates the degree of LV systolic dysfunction o Useful in serial monitoring to assess recovery of function o May quickly identify other potential causes of new cardiomyopathy (i.e., ischemic or valvular) Nuclear Medicine Findings 557

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Rarely used Antimyosin scintigraphy can identify myocardial inflammation o High sensitivity (91-100%) and high negative predictive value (93-100%) o Low specificity (31-44%) and low positive predictive value (28-33%)  Gallium scanning used to detect severe myocardial cellular infiltration o Good negative predictive value o Low specificity Imaging Recommendations  Best imaging tool o Cardiac MR  Protocol advice o MR: T2WI for edema; pre- and post-contrast T1WI for global relative enhancement; delayed enhancement for myocardial inflammation; cine SSFP for function DIFFERENTIAL DIAGNOSIS Ischemic Cardiomyopathy  Delayed-enhancement pattern is subendocardial and confined to coronary territory Nonischemic Dilated Cardiomyopathy  Midwall hyperenhancement in septum P.7:28

Infiltrative Cardiomyopathy  Patchy delayed enhancement PATHOLOGY General Features  Etiology o Multiple etiologies exist; however, often classified as idiopathic o Infectious viral etiologies are most frequent  Coxsackie B is the most common viral pathogen o Other causes include autoimmune disorders, toxic/ischemic/mechanical injury, drug related, transplant related  Endomyocardial biopsy is of limited utility and generally reserved for patients with major clinical manifestations  Diagnosed by histological, immunological, and immunochemical criteria  Clinicopathologic classification provides prognostic information  Myocardial damage has 2 main phases o Acute phase (1st 2 weeks): Myocyte destruction is a direct consequence of offending agent o Chronic phase: Continuing myocyte destruction is autoimmune in nature Staging, Grading, & Classification  WHO Marburg classification (1996) o Cell types: Lymphocytic, eosinophilic, neutrophilic, giant cell, granulomatous, or mixed o Distribution: Focal (outside vessel lumen), confluent, diffuse, or reparative (in fibrotic areas) o Amount: None (grade 0), mild (grade 1), moderate (grade 2), or severe (grade 3) CLINICAL ISSUES Presentation  Most common signs/symptoms o Variable clinical presentation from subclinical to acute heart failure with hemodynamic compromise o Majority of symptomatic cases with syndrome of heart failure and dilated cardiomyopathy  Fatigue and decreased exercise capacity  Other signs/symptoms o ECG changes: ST-segment elevation or T-wave inversion  May mimic myocardial ischemia o Elevated biomarkers  Cardiac biomarkers (CK, CK MB, troponin)  Erythrocyte sedimentation rate o Cardiogenic shock o Sudden cardiac death Demographics 558

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Epidemiology o Often secondary to infection, either direct viral infection or postviral, immune-mediated reaction o True incidence of idiopathic or “viral” myocarditis is unknown o Estimated that myocarditis is responsible for  10% of unexplained dilated cardiomyopathy and heart failure  12% of young adults presenting with sudden death Natural History & Prognosis  Majority of cases have a benign course  Some patients develop heart failure, serious arrhythmias, disturbances of conduction, or even circulatory collapse  2/3 with mild symptoms recover completely  1/3 subsequently develop dilated cardiomyopathy Treatment  Nonsteroidal anti-inflammatory drugs are not effective and may actually enhance myocarditis and increase mortality  Exercise restriction, electrocardiographic monitoring, anticoagulation, antiarrhythmic drugs in selected patients  Transplant in cases of cardiogenic shock  Colchicine DIAGNOSTIC CHECKLIST Consider  Cardiac MR study should be performed if patient is symptomatic with clinical suspicion for myocarditis (i.e., chest pain, elevated troponin, normal coronary arteries, and suspected viral etiology) o Myocardial infarction should be ruled out before performing cardiac MR Image Interpretation Pearls  Lake Louise consensus criteria: Study is consistent with myocarditis if 2 of 3 MR criteria (T2 ratio, T1 global relative enhancement, late gadolinium enhancement) are positive  Repeat cardiac MR 1-2 weeks after initial exam if none of the criteria are present but onset of symptoms is recent and there is strong clinical suspicion for myocarditis  MR performed during 1st day of myocarditis is less sensitive than MR obtained 7 or more days after onset of disease Reporting Tips  MR report should include o LV volume and function o Presence or absence of markers of inflammatory activity and injury (T2 ratio, T1 global relative enhancement, late gadolinium enhancement) o Presence or absence of pericardial effusion SELECTED REFERENCES 1. Grün S et al: Long-term follow-up of biopsy-proven viral myocarditis: predictors of mortality and incomplete recovery. J Am Coll Cardiol. 59(18):1604-15, 2012 2. Friedrich MG et al: Cardiovascular magnetic resonance in myocarditis: A JACC White Paper. J Am Coll Cardiol. 53(17):1475-87, 2009 3. Abdel-Aty H et al: Diagnostic performance of cardiovascular magnetic resonance in patients with suspected acute myocarditis: comparison of different approaches. J Am Coll Cardiol. 45(11):1815-22, 2005 4. Liu PP et al: Cardiovascular magnetic resonance for the diagnosis of acute myocarditis: prospects for detecting myocardial inflammation. J Am Coll Cardiol. 45(11):1823-5, 2005 P.7:29

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(Left) Axial T1WI pre-contrast MR shows ROIs drawn over the left ventricular myocardium and skeletal muscle. (Right) Axial T1WI post-contrast MR at identical slice position with ROI drawn over identical locations in the left ventricular myocardium and skeletal muscle is used to calculate the global relative enhancement ratio (positive GRE is > 4.0). The degree of myocardial relative hyperenhancement is 1 criterion toward the diagnosis of myocarditis.

(Left) Short-axis T2WI MR shows ROIs drawn over the left ventricular myocardium and skeletal muscle. The ratio of myocardial T2 signal relative to skeletal muscle signal is 1 criterion toward the diagnosis of myocarditis (abnormal is T2 ratio > 1.9). (Right) Four-chamber late gadolinium enhancement MR demonstrates subepicardial late gadolinium enhancement involving the septal, apical, and lateral left ventricle, which is not confined to a coronary territory .

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(Left) Late gadolinium enhancement MR demonstrates diffuse subepicardial delayed enhancement in the basal to apical lateral left ventricular wall with sparing of the subendocardial myocardium . (Right) Short-axis late gadolinium enhancement MR demonstrates near transmural late gadolinium enhancement (with sparing of the subendocardial region) involving the lateral wall of the left ventricle . Note pericardial effusion , a finding commonly seen in myocarditis.

Arrhythmogenic RV Dysplasia/Cardiomyopathy Key Facts Terminology  Distinct cardiomyopathy thought to be caused by mutations in genes coding for desmosomal proteins (e.g., plakoglobin, plakophilin, desmophilin, and desmocollin) o Results in apoptosis and early cell death with fibrofatty replacement o Predominantly affects right ventricle (RV) with variable left ventricle (LV) involvement o Frequently associated with arrhythmias, including sudden cardiac death Imaging  Diagnosis is made by using a set of major and minor criteria in 6 categories  Imaging can supply only 1 major or minor criterion  “Triangle of dysplasia” (RV free wall extending from just below tricuspid valve to RV apex and RV outflow tract [RVOT]) is most commonly involved  RV is usually dilated and shows impaired systolic function  RV microaneurysms and thickened trabeculae are often evident  RVOT is commonly dilated and poorly contractile  LV is involved in ≥ 15% of cases and may predominate in small percentage of cases  Attempts to visualize intramyocardial fat are no longer advised since they frequently result in misdiagnosis  May demonstrate delayed hyperenhancement of RV wall representing fibrosis in 2/3 of cases Top Differential Diagnoses  Cardiac sarcoid  RV infarction  RV volume overload  Myocarditis  Idiopathic RVOT tachycardia

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(Left) Oblique cardiac CT shows globally dilated right ventricle (RV) with severely thinned and scalloped anterior free wall in a patient who met criteria for arrhythmogenic RV dysplasia (ARVD). Artifact from a pacer lead is also noted . (Right) RV outflow tract (RVOT) MR cine in a patient with arrhythmogenic RV cardiomyopathy (ARVC) shows the “triangle of dysplasia” extending from the subtricuspid region to the RV apex and superiorly to the infundibulum. Note the irregular outpouchings along the superior margin of the RV.

(Left) Four-chamber view MR cine images in diastole (top) and systole (bottom) in a patient with documented ARVC show dilatation of the RV and prominent trabeculations . Also note the poor systolic function evidenced by the lack of change in the volume of the RV from diastole to systole. (Right) Four-chamber view late gadolinium enhancement (LGE) image of the same patient demonstrates extensive enhancement of the RV free wall and of the septum . P.7:31

TERMINOLOGY Abbreviations  Arrhythmogenic right ventricular dysplasia (ARVD)  Arrhythmogenic right ventricular cardiomyopathy (ARVC) Definitions  Distinct cardiomyopathy thought to be caused by mutations in genes coding for desmosomal proteins (e.g., plakoglobin, plakophilin, desmophilin, and desmocollin) o Results in apoptosis and early cell death with fibrofatty replacement o Predominantly affects right ventricle (RV), with variable left ventricular (LV) involvement, and is frequently associated with arrhythmias including sudden cardiac death (SCD) IMAGING 562

Diagnostic Imaging Cardiovascular General Features  Best diagnostic clue o Diagnosis is made on basis of 2010 task force criteria representing combination of clinical, pathologic, electrophysiological, and imaging information o Diagnosis is considered definite when 2 major, or 1 major and 2 minor, or 4 minor criteria from different categories are present  Note that imaging can supply only 1 major or minor criterion  Location o “Triangle of dysplasia” (RV free wall extending from just below tricuspid valve to RV apex and RVOT) is most commonly involved  LV involved in ≥ 15% of cases and may predominate in small percentage of cases  Size o Often, entire RV free wall is involved, but extent of RV involvement is variable and may progress over time  Minimal involvement of subtricuspid RV free wall may result in “accordion” sign, wherein regional wall motion abnormality (RWMA) results in focal area of dyskinesia resembling accordion  Morphology o RV is commonly dilated in proven cases, with wall thinning and hypertrabeculation apparent  RV free wall microaneurysms and dyskinetic segments are noted on cine imaging  RVOT is commonly dilated and poorly contractile Radiographic Findings  Radiography o Chest radiography findings are usually normal and rarely show RV dilatation CT Findings  CTA o Dilated RV with reduced systolic function (requires multiphase gated image acquisition) MR Findings  SSFP white blood cine o RV is usually visibly dilated, with impaired function and RWMA often seen in “triangle of dysplasia” o RV microaneurysms and thickened trabeculae o MR can supply 1 diagnostic task force criterion when RWMA or dyssynchronous RV contraction are noted and severe (major) or moderate (minor) RV dilatation or decreased RV ejection fraction (RVEF) is present  Major: ≥ 110 mL/m2 (male); ≥ 100 mL/m2 (female); RVEF ≤ 40%  Minor: ≥ 100 to < 110 mL/m2 (male); ≥ 90 to < 100 mL/m2 (female); RVEF > 40% to ≤ 45%  Black blood SE o Attempts to visualize intramyocardial fat are not part of task force criteria, due to high retest and interobserver variability and potential to result in misdiagnosis  Late gadolinium enhancement o May demonstrate delayed enhancement of RV wall representing fibrosis in 2/3 of cases but is not task force criterion Echocardiographic Findings  Echocardiogram o Hypokinetic and dilated RV with decreased RV ejection fraction o Echo can supply 1 diagnostic task force criterion when severe (major) or moderate (minor) RV dysfunction is noted Angiographic Findings  May provide diagnostic criterion if regional RV akinesia, dyskinesia, or aneurysm are noted (global or regional dysfunction and structural abnormalities category) Imaging Recommendations  Best imaging tool o MR is excellent for RV volumes and morphology o Delayed enhancement of RV is seen in 2/3 of cases and correlates with inducibility of arrhythmias  Protocol advice o Cine MR imaging through entire RV is essential, with views of RVOT in long axis and short axis in addition to stack of 4-chamber views DIFFERENTIAL DIAGNOSIS Cardiac Sarcoidosis 563

Diagnostic Imaging Cardiovascular  May mimic ARVC with dilated, poorly functioning RV with abnormal delayed enhancement  More commonly has septal and LV involvement Right Ventricular Infarction  Usually associated with inferior wall LV infarct (right coronary artery territory)  Not commonly associated with localized aneurysm formation Right Ventricular Volume Overload  Atrial septal defect o Has normal or hyperdynamic function  Repaired tetralogy of Fallot o Often has significant pulmonic regurgitation with RV volume overload and failure RV Dilatation in Endurance Athletes  Marathon runners and other endurance athletes often develop RV dilatation P.7:32

o RV function is usually preserved Myocarditis  Selective RV involvement uncommon; usually LV involvement predominates  Often patchy without predilection for “triangle of dysplasia” Idiopathic RV Outflow Tachycardia  Benign, nonfamilial condition that may clinically mimic ARVC o No imaging abnormality is seen PATHOLOGY General Features  Etiology o Mutations in genes coding for desmosomal proteins lead to early apoptosis, likely hastened by “wear and tear,” which is particularly induced by repetitive exercise  Genetics o Multiple mutations are now recognized, with predominantly autosomal dominant heritability but with variable penetrance  Mutations of plakophilin (most common), desmoglein, desmoplakin, and desmocollin  Cardiac ryanodine receptor defect: Calcium released from sarcoplasmic reticulum; may be responsible for adrenergically mediated arrhythmias o Family history may provide task force criterion if 1st-degree relative with proven (major) or suspected (minor) ARVC Gross Pathologic & Surgical Features  Apparent RV dilation and wall thinning  Involves LV in 40-76% of autopsy cases Microscopic Features  Biopsy findings demonstrating myocyte depletion with fibrous replacement may provide task force criterion  Fibrofatty infiltration of myocardium on biopsy is no longer major task force criterion CLINICAL ISSUES Presentation  Most common signs/symptoms o Early (“concealed”) phase: Patients are often asymptomatic but may be at risk of SCD due to arrhythmia o Overt (“electrical”) phase: Patients present with symptomatic arrhythmias, and RV morphologic abnormalities are usually detectable with imaging  Characteristic arrhythmia is that of ventricular tachycardia with left bundle branch block morphology  Other signs/symptoms o Palpitations are very common once symptoms develop  Clinical profile o Should be considered in athletes of any age as cause of syncope or cardiovascular collapse  Causes 15-25% of SCD in patients < 35 years of age  Can lead to isolated RV or biventricular heart failure  Diagnosis

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Made on basis of task force criteria representing combination of clinical, pathologic, electrophysiological, and imaging information

Demographics  Age o Most commonly present in early adulthood  Gender o M:F = 3:1 in younger age groups o M = F in later-onset cases  Epidemiology o Estimated incidence: 1 in 2,000 to 1 in 5,000 Natural History & Prognosis  Annual mortality rate: ˜ 2% Treatment  Avoid vigorous athletics  In absence of arrhythmias, β-blocker therapy is appropriate  Implantable cardioverter defibrillator o In patients with history of ventricular tachyarrhythmia, cardiac arrest, or syncope o Antiarrhythmics may be needed for repeated discharges (sotalol has shown some efficacy)  Preload reduction therapy is currently under investigation DIAGNOSTIC CHECKLIST Image Interpretation Pearls  Cine MR imaging and volumetric analysis are often very helpful in providing imaging support for diagnosis  MR, echo, and RV angiography can supply only 1 criterion and belong to same category (global or regional dysfunction/structural abnormalities) SELECTED REFERENCES 1. Basso C et al: Arrhythmogenic right ventricular cardiomyopathy. Circ Arrhythm Electrophysiol. 5(6):1233-46, 2012 2. Steckman DA et al: Utility of cardiac magnetic resonance imaging to differentiate cardiac sarcoidosis from arrhythmogenic right ventricular cardiomyopathy. Am J Cardiol. 110(4):575-9, 2012 3. Marcus FI et al: Diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia: proposed modification of the task force criteria. Circulation. 121(13):1533-41, 2010 4. Bomma C et al: Evolving role of multidetector computed tomography in evaluation of arrhythmogenic right ventricular dysplasia/cardiomyopathy. Am J Cardiol. 100(1):99-105, 2007 5. Tandri H et al: Magnetic resonance imaging of arrhythmogenic right ventricular dysplasia: sensitivity, specificity, and observer variability of fat detection versus functional analysis of the right ventricle. J Am Coll Cardiol. 48(11):2277-84, 2006 6. Tandri H et al: Noninvasive detection of myocardial fibrosis in arrhythmogenic right ventricular cardiomyopathy using delayed-enhancement magnetic resonance imaging. J Am Coll Cardiol. 45(1):98-103, 2005 7. Tandri H et al: Magnetic resonance imaging findings in patients meeting task force criteria for arrhythmogenic right ventricular dysplasia. J Cardiovasc Electrophysiol. 14(5):476-82, 2003 P.7:33

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(Left) Short-axis MR cine images in diastole (left) and systole (right) demonstrate RV dilatation and decreased function in a patient with ARVC. Note the tiny focal outpouchings, often termed “microaneurysms,” along the RV free wall in the systolic image. (Right) Short-axis late gadolinium enhancement image of the same patient shows enhancement of the RV wall , consistent with fibrosis. This finding is seen in ˜ 2/3 of patients with ARVC.

(Left) Four-chamber view MR cine (top) and LGE (bottom) in a patient with ARVC show tiny foci of fat along the RV side of the septum , denoted by the “etching” artifact seen in this steady-state free precession image. Note the enhancement of the same area of the septum and the RV free wall on the LGE image. (Right) Axial MR cine images through the RVOT in diastole (left) and systole (right) in a patient with ARVC show bulging of the RVOT in systole .

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(Left) Four-chamber view MR cine (left) in a patient with minimal involvement by ARVC shows a focal systolic outpouching, termed the “accordion” sign, along the RV free wall in the subtricuspid region . Note also that this is the only region with abnormal enhancement on the LGE image (right). (Right) Short-axis (top) and 4-chamber (bottom) LGE images in a patient with cardiac sarcoidosis demonstrate abnormal RV enhancement similar to findings seen in ARVC.

Endomyocardial Fibrosis Key Facts Terminology  Disorder characterized by development of subendocardial fibrous and restrictive cardiomyopathy o Endocardial fibrosis involves inflow tracts of right and left ventricles  This restrictive scarring prevents ventricular filling and tethering of papillary muscles, leading to valvular regurgitation Imaging  Late gadolinium enhancement MR: Best noninvasive tool for detection of endomyocardial fibrosis (EMF)  Cardiac MR: Best modality to confirm typical EMF pattern o Depicts thrombus and restrictive physiology  Echocardiography: First-line tool to detect restrictive physiology and obliterative changes  Coronary CTA: May be used selectively for exclusion of coronary artery disease  Invasive ventriculogram: “Mushroom” sign describes shape of affected ventricle when apex is obliterated completely by fibrosis Top Differential Diagnoses  Constrictive pericarditis  Noncompaction of myocardium  Apical hypertrophic cardiomyopathy Clinical Issues  Initial manifestation in most patients is right ventricular failure even if there is biventricular involvement  Medical therapy includes immunosuppressive and cytotoxic medications  Surgical endocardial decortication for classes III and IV is controversial

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(Left) Chest radiograph shows mild cardiomegaly with right atrial enlargement and decreased pulmonary blood flow in a patient with right-sided endomyocardial fibrosis. (Right) Four-chamber view echocardiogram shows an intraventricular mass-like lesion in the right ventricle (RV) and enlargement of the right atrium in a patient with right-sided endomyocardial fibrosis and no evidence of disease in the left ventricle (LV).

(Left) Four-chamber view MR cine shows midapical obliteration of RV , dilated right atrium, and a small pericardial effusion. There is also mild LV apical obliteration. (Right) Four-chamber view LGE MR shows RV endocavitary thrombus and endomyocardial late enhancement in a patient with eosinophilic leukemia (Löffler endocarditis). The LV apex also has focal endocardial late enhancement consistent with endocardial fibrosis. P.7:35

TERMINOLOGY Abbreviations  Endomyocardial fibrosis (EMF) Synonyms  Davies disease  Restrictive obliterative cardiomyopathy  Löffler endocarditis  Endocarditis parietalis fibroplastica Definitions  Idiopathic disorder characterized by development of subendocardial fibrosis and restrictive cardiomyopathy o Endocardial fibrosis involves inflow tracts of right ventricle and left ventricle o This restrictive scarring prevents ventricular filling 568

Diagnostic Imaging Cardiovascular o Tethering of papillary muscles leads to valvular regurgitation IMAGING General Features  Best diagnostic clue o Detection of EMF by late-enhancement MR is best noninvasive diagnostic tool o Ventricular apex obliteration by fibrous formation in endomyocardium of patient with diastolic heart failure is found in few other diseases o Relatively normal-sized heart in patient with signs/symptoms of severe heart failure o Associated signs of right &/or left heart failure: Systemic/pulmonary venous congestion, dilated atria, atrioventricular valve regurgitation  Location o 45% biventricular o 40% right ventricle o 5% left ventricle  Morphology o Generalized cardiomegaly is unusual because ventricles are not typically dilated  Atrial enlargement may modify cardiac silhouette Imaging Recommendations  Best imaging tool o Echocardiography: First-line tool to detect restrictive physiology and obliterative changes o Cardiac MR: Best tool to demonstrate typical EMF pattern and detect mural thrombus o Coronary CTA: May be used selectively for exclusion of coronary artery disease o Invasive ventriculogram: “Mushroom” sign describes shape of affected ventricle when apex is obliterated completely by fibrosis  Protocol advice o Late-enhancement and cine-SSFP images should be part of cardiac MR protocol  On late-enhancement images, low signal intracardiac lesion typically represents thrombus  Subendocardial or endocardial late enhancement indicates inflammatory infiltration (earlystage EMF) or fibrosis (late-stage EMF)  Cine-SSFP images permit accurate morphologic and functional heart evaluation and exclusion of pericardial thickening Radiographic Findings  Chest radiography o Predominantly atrial enlargement according to EMF type (right or left atrium) o Reduced pulmonary vessel markings in right-sided form o Pulmonary congestion in left-sided involvement MR Findings  Cardiac MR o Noninvasive gold standard for atrial and ventricular volumetrics o Demonstrates typical apical obliteration of involved ventricle o Shows small or normal-size ventricle(s) with atrial dilation o Detects thrombus and inflammatory/fibrotic changes in endocardial surface through late enhancement o Allows highly accurate and histologically correlated noninvasive tissue characterization o May demonstrate fibrosis extending via chordae tendineae to atrioventricular valves where it causes tethering and regurgitation  May lead to atrial enlargement o Shows pericardial effusion when present Echocardiographic Findings  Apical obliteration  Thrombi adherent to endocardial surface  Mitral and tricuspid regurgitation jets  Small or normal-sized ventricle(s) with atrial dilation  Restrictive filling pattern by tissue Doppler Angiographic Findings  Left and right ventriculography o Distortion of chamber morphology by fibrosis and obliteration o Variable degrees of mitral and tricuspid regurgitation o Hemodynamic findings consistent with restrictive cardiomyopathy 569

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Elevated end-diastolic pressures in involved ventricle Variance between right and left ventricular diastolic pressures is more likely to be > 5 mm Hg  Invasive coronary angiography o Coronary arteries are usually normal DIFFERENTIAL DIAGNOSIS Constrictive Pericarditis  Tubular appearance of ventricles on 4-chamber view  Elliptical-shaped left ventricle on short-axis view (diastolic phase)  Pericardial thickening > 4 mm o Beware of calcified pericardium: Will have pericardial signal loss on T1 and T2  Focal or diffuse pericardial enhancement on CE-MR may indicate either inflammation or fibrosis, more frequently over right heart chambers and right atrioventricular groove  Dilated superior/inferior vena cava  Septal bounce on real-time MR echo indicates ventricular interdependence  Tag lines across pericardium P.7:36  Negative MR exam makes constrictive pericarditis very unlikely Noncompaction of Myocardium  Characterized by persistent embryonic myocardial morphology o 2-layered appearance of ventricle  Noncompacted to compacted thickness ratio of > 2.3:1 is diagnostic  Noncompaction more frequently affects apex and inferolateral segments of left ventricle Apical Hypertrophic Cardiomyopathy  No myocardial hypertrophy in EMF  Late-enhancement areas appear on late-enhancement MR images o Located mainly in midwall myocardium o Patchy in distribution, sparing endocardial surface PATHOLOGY General Features  Etiology o Etiology of EMF has not been established o Potential causes include  Infection  Parasites and protozoans (e.g., filariasis, malaria)  Inflammation  Hypereosinophilic states  Nutrition  General malnutrition  Cassava toxicity  Drugs Gross Pathologic & Surgical Features  Heart size is usually not enlarged, but biatrial enlargement can be seen with valve dysfunction  Ventricular cavities distorted by endocardial thickening and thrombosis of inflow tract and apex of 1 or both ventricles  Atrial volumes are increased secondary to regurgitation and restrictive physiology Microscopic Features  Case for equivalence of end-stage eosinophilic (Löffler) endocarditis and EMF is based on histological comparison o Olsen proposed 3 stages of Löffler endocarditis  0-5 weeks: Acute myocarditis with necrosis of subendocardium  After 10 months: Thrombus formation over initial lesions with decrement in amount of inflammatory activity  After years of activity: Fibrotic phase, when endocardium is replaced by fibrosis o Some investigators found inverse relationship between eosinophil levels and duration of EMF disease 570

Diagnostic Imaging Cardiovascular CLINICAL ISSUES Presentation  Most common signs/symptoms o Initial manifestation in most patients is right ventricular failure even if there is biventricular involvement  Right ventricular involvement  Raised jugular venous pulse  Hepatomegaly  Ascites  Peripheral edema o At time of diagnosis, most patients are in class III or IV (New York Heart Association)  Other signs/symptoms o Left ventricular involvement  Dyspnea  Bibasal crackles  S3 Demographics  Age o Older children (aged 5-15 years) and young adults  Gender o Women of reproductive age and children are more commonly affected than men  Epidemiology o Tropical EMF  90% of cases in tropical and subtropical regions of Africa, India, and South America  EMF is most common type of restrictive cardiomyopathy in tropical countries Natural History & Prognosis  Poor overall prognosis  90% mortality rate at 2 years after onset of symptoms Treatment  Medical o Löffler endocarditis: Immunosuppressive and cytotoxic medications with varying degrees of success  Surgical o Endocardial decortication for classes III and IV o Successful surgery has clear benefit on symptoms and seems to favorably affect survival as well o Recurrence occurs in 15% of cases postoperatively SELECTED REFERENCES 1. León D et al: Usefulness of cardiac MRI in the early diagnosis of endomyocardial fibrosis. Rev Port Cardiol. 31(5):401-2, 2012 2. Mocumbi AO et al: Echocardiography accurately assesses the pathological abnormalities of chronic endomyocardial fibrosis. Int J Cardiovasc Imaging. 27(7):955-64, 2011 3. Qureshi N et al: MR imaging of endomyocardial fibrosis (EMF). Int J Cardiol. 149(1):e36-7, 2011 4. Salemi VM et al: Late gadolinium enhancement magnetic resonance imaging in the diagnosis and prognosis of endomyocardial fibrosis patients. Circ Cardiovasc Imaging. 4(3):304-11, 2011 5. Rost C et al: Obstructive endocardial thrombosis in endomyocardial fibrosis. Heart. 96(20):1686-7, 2010 6. Bukhman G et al: Endomyocardial fibrosis: still a mystery after 60 years. PLoS Negl Trop Dis. 2(2):e97, 2008 7. Marijon E et al: Typical clinical aspect of endomyocardial fibrosis. Int J Cardiol. 112(2):259-60, 2006 8. Hassan WM et al: Pitfalls in diagnosis and clinical, echocardiographic, and hemodynamic findings in endomyocardial fibrosis: a 25-year experience. Chest. 128(6):3985-92, 2005 P.7:37

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(Left) Short-axis T2WI MR shows high signal in anterolateral segment , papillary muscles , and inferoseptal segment , consistent with multifocal acute myocardial edema. Patient's peripheral eosinophil count was 27,000 on admission. (Right) Corresponding short-axis late gadolinium enhancement (LGE) image shows subendocardial LGE in multiple LV segments , endocardial LGE on RV side of interventricular septum indicating RV involvement, and papillary muscle LGE .

(Left) Corresponding 4-chamber view shows extent of LV subendocardial LGE and RV endocardial LGE . Note biatrial enlargement, which is indicative of restrictive physiology. (Right) Corresponding axial high-resolution CT shows septal lines in the anterior segments of both upper lobes. Transbronchial biopsy revealed extensive peribronchial eosinophilic infiltration.

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(Left) Four-chamber view LGE MR detects small ventricles with apical obliteration and dilated atria. Observe endomyocardial abnormal delayed enhancement consistent with fibrosis on both RV and LV , with an apical predominance. (Right) LVOT MR cine image shows apical obliteration and LV dilatation, which are typical findings of endomyocardial fibrosis. Note low-signal area on the endocardial surface of the apex , which may be due to fibrosis or thrombus.

Hypereosinophilic Syndrome Key Facts Terminology  Unexplained hypereosinophilia (> 1,500/µL) of ≥ 6 months duration associated with organ dysfunction due to eosinophilic infiltration o Heart is most commonly involved organ (cardiac involvement in up to 60% of cases)  Deemed to be subtype of endomyocardial fibrosis associated with hypereosinophilia  Synonyms: Eosinophilic myocarditis, Löffler (or Loeffler) myocarditis Imaging  MR cine o Affected ventricular apices often appear filled with amorphous isointense material that represents thrombus, with seemingly apical obliteration o Thrombus &/or subsequent intracavitary fibrosis can impair function of chordae tendineae, resulting in valvular regurgitation o Restrictive cardiomyopathy can occur secondary to cavity obliteration by thrombus or by fibrosis in later stages of disease  Late gadolinium enhancement MR o Intense endocardial enhancement is noted involving interface between nonenhancing intracavitary thrombus and nulled myocardium o Images with long inversion time (600 milliseconds) are helpful in demonstrating intracavitary thrombi  Perfusion imaging and early (< 3 minutes) delayed-enhancement MR images are often useful to define cleavage plane between thrombus and enhancing, inflamed endocardium Top Differential Diagnoses  Endomyocardial fibrosis  Apical thrombus  Apical hypertrophic cardiomyopathy  Left ventricular noncompaction

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(Left) Four-chamber view MR cine in a patient with hypereosinophilic syndrome (HES) shows homogeneous thrombus filling the right ventricular (RV) apex and limiting RV filling. Note that the thrombus is isointense to the myocardium. (Right) RV 2-chamber (left) and short-axis (right) MR cine images of the same patient demonstrate the extensive thrombus formation filling the RV apex and extending into the outflow tract. Note the marked compromise of the right ventricular cavity produced by this process.

(Left) Four-chamber (left) and RV 2-chamber (right) MR perfusion images demonstrate intense subendocardial enhancement of the RV wall subjacent to the dark, nonenhancing thrombus. This represents the inflammation seen in HES. (Right) Four-chamber (left) and RV 2-chamber (right) LGE MR images show the characteristic subendocardial enhancement of HES . The image on the right is obtained with a long inversion time (600 milliseconds) to better demonstrate the thrombus . P.7:39

TERMINOLOGY Abbreviations  Hypereosinophilic syndrome (HES) Synonyms  Eosinophilic myocarditis, Löffler (or Loeffler) myocarditis Definitions  Unexplained hypereosinophilia (> 1,500/µL) of ≥ 6 months duration associated with organ dysfunction due to eosinophilic infiltration o Heart is most commonly involved organ (cardiac involvement in up to 60% of cases)  Thought of as subtype of endomyocardial fibrosis that is specifically associated with hypereosinophilia 574

Diagnostic Imaging Cardiovascular IMAGING General Features  Best diagnostic clue o Characteristic MR findings are essentially pathognomonic when present o Contrast-enhanced CT may reproduce many MR findings, but tissue characterization is superior with MR  Location o Ventricular apices are predominantly involved, with subsequent fibrosis extending to chordae tendineae of atrioventricular valves, impairing their function  Morphology o Typically results in “arrowhead” configuration of 1 or both apices with laminated thrombus layered over inflamed apical ventricular endocardium Imaging Recommendations  Best imaging tool o Contrast-enhanced MR  Gated cardiac CTA may be substituted in patients unable to undergo MR o Echocardiography is often recommended as first-line tool but is less sensitive in detecting thrombus  Transthoracic echo frequently has technical limitations in evaluation of apices  Protocol advice o Standard cardiac MR exam with the usual SSFP cine imaging in short-axis and long-axis planes should be supplemented with  Early-enhancement images with short inversion time (TI = 250-300 milliseconds) to evaluate for subendocardial inflammation/fibrosis  Late-enhancement images with long inversion time (TI = 600 milliseconds) to evaluate for thrombus  Perfusion imaging, which is helpful in demonstrating interface of avascular thrombus with underlying inflamed myocardium MR Findings  MR cine o Affected ventricular apices often appear filled with amorphous isointense material that represents thrombus with seemingly apical obliteration o Thrombus &/or subsequent intracavitary fibrosis can impair function of chordae tendinea, resulting in valvular regurgitation o Restrictive cardiomyopathy can occur secondary to cavity obliteration by thrombus or by fibrosis in later stages of disease  Produces diastolic dysfunction with biatrial enlargement, reflecting difficulty filling the heart  Late gadolinium enhancement MR o Intense endocardial enhancement is noted involving interface between nonenhancing intracavitary thrombus and nulled myocardium o Images with long inversion time (TI = 600 milliseconds) are helpful in demonstrating intracavitary thrombi  Perfusion imaging and early (< 3 minutes) delayed-enhancement MR images are often useful in defining cleavage plane between thrombus and enhancing, inflamed endocardium CT Findings  Cardiac gated CTA o Will demonstrate intracavitary thrombus and findings of restrictive physiology  Retrospectively gated acquisitions may allow evaluation of mitral/tricuspid valve dysfunction  Delayed scan may be useful to differentiate thrombus from tumor DIFFERENTIAL DIAGNOSIS Endomyocardial Fibrosis  Has similar pathophysiology to Loeffler endocarditis but is not associated with hypereosinophilia Apical Thrombus  Often attached to areas of prior infarction Apical Hypertrophic Cardiomyopathy  Apical cavity obliteration is seen with this disorder o Cavity obliteration due to hypertrophied muscle, not thrombus  Delayed-enhancement MR pattern is markedly different, with patchy intramyocardial uptake seen at apex 575

Diagnostic Imaging Cardiovascular Left Ventricular Noncompaction  Produces hypertrabeculated appearance at apices  May have associated thrombi, but these do not obliterate cavity Other Causes of Restrictive Cardiomyopathy  Not morphologically similar or confusing but may result in similar physiology  Amyloidosis is most common identifiable cause of restrictive pattern PATHOLOGY General Features  Etiology o Majority of HES cases remain idiopathic in origin, but subtypes with specific hematologic profiles are now recognized P.7:40 

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Myeloproliferative variant comprises 10-15% of cases  Results from FIP1L1-PDGFRA gene-fusion mutation of tyrosine kinase  In > 90% of these cases, patients have complete remission with imitanib, a tyrosine kinase inhibitor Lymphocytic variant comprises ˜ 15% of cases  Results from secretion of eosinophilopoietic cytokines by aberrant populations of T cells

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Genetics o Most cases are sporadic  Familial cases occur but are very rare Gross Pathologic & Surgical Features  Eosinophilic infiltration of endocardium leads to subendocardial inflammation and necrosis o These changes are most prominent at ventricular apices  Inflamed endocardium serves as nidus for thrombus formation with subsequent fibrosis o This fibrosis often entraps chordae tendineae of mitral &/or tricuspid valves, leading to dysfunction  Thrombus formation and subsequent endomyocardial fibrosis cause reduction of ventricular cavity volume and marked stiffening of affected ventricle, resulting in restrictive physiology  Atrial enlargement often occurs as a result of valvular dysfunction &/or diminished ventricular compliance CLINICAL ISSUES Presentation  Most common signs/symptoms o Dyspnea is most common presenting symptom, followed by chest pain and cough o Biventricular congestive heart failure  Right heart symptoms often predominate  Other signs/symptoms o Fever, night sweats, weight loss, myalgias, dyspnea, nonproductive cough, and generalized fatigue Demographics  Age o Patients are typically in their 40s or 50s at diagnosis, but range is from childhood to late adulthood  Gender o Once thought to have > 80% male predominance, but more recent series suggest only slight male predominance (60%)  Epidemiology o Very rare disorder  Exact prevalence is uncertain Natural History & Prognosis  3 stages of disease progression o Acute necrotic stage  Infiltration of endocardium and myocardium with eosinophils leading to inflammatory changes within endocardium and myocardium o Thrombotic-necrotic stage  Formation of thrombi along damaged endocardium of ventricles and (occasionally) right atrium o Late fibrotic stage 576

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Progressive scarring leading to entrapment of chordae tendineae, which results in mitral &/or tricuspid regurgitation  Cardiac involvement often has poor prognosis despite therapy o Reported 5-year survival rate: < 50% Treatment  High-dose steroids (> 40 mg/day) are mainstay of therapy for idiopathic and lymphocytic types  Imatinib is first-line therapy for myeloproliferative variant  Cytotoxic agents/monoclonal antibodies against interleukin 5 are usually reserved for treatment failures  Anticoagulation is often used to treat thrombotic complications  Conventional heart failure therapy, including diuretics and afterload reduction, may be useful  Heart transplant is occasionally performed DIAGNOSTIC CHECKLIST Consider  Eosinophilic myocarditis in patients with apical cavity obliteration by thrombus along with characteristic delayed-enhancement pattern Image Interpretation Pearls  Differentiation of hypereosinophilic syndrome from apical hypertrophic cardiomyopathy is facilitated by dynamic cine MR and late gadolinium enhancement MR imaging SELECTED REFERENCES 1. Hoey ET et al: Cardiovascular MRI for assessment of infectious and inflammatory conditions of the heart. AJR Am J Roentgenol. 197(1):103-12, 2011 2. Kleinfeldt T et al: Cardiac manifestation of the hypereosinophilic syndrome: new insights. Clin Res Cardiol. 99(7):419-27, 2010 3. Ogbogu PU et al: Hypereosinophilic syndrome: a multicenter, retrospective analysis of clinical characteristics and response to therapy. J Allergy Clin Immunol. 124(6):1319-25, 2009 4. Chao BH et al: Fatal Loeffler's endocarditis due to hypereosinophilic syndrome. Am J Hematol. 82(10):920-3, 2007 5. Klion AD et al: Approaches to the treatment of hypereosinophilic syndromes: a workshop summary report. J Allergy Clin Immunol. 117(6):1292-302, 2006 6. Cury RC et al: Images in cardiovascular medicine. Visualization of endomyocardial fibrosis by delayed-enhancement magnetic resonance imaging. Circulation. 111(9):e115-7, 2005 7. Salanitri GC: Endomyocardial fibrosis and intracardiac thrombus occurring in idiopathic hypereosinophilic syndrome. AJR Am J Roentgenol. 184(5):1432-3, 2005 8. Bishop GG et al: Hypereosinophilic syndrome and restrictive cardiomyopathy due to apical thrombi. Circulation. 104(2):E3-4, 2001 9. Puvaneswary M et al: Idiopathic hypereosinophilic syndrome: magnetic resonance imaging findings in endomyocardial fibrosis. Australas Radiol. 45(4):524-7, 2001 10. Ommen SR et al: Clinical and echocardiographic features of hypereosinophilic syndromes. Am J Cardiol. 86(1):1103, 2000 P.7:41

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(Left) Four-chamber view MR cine of another patient with HES shows an asymmetric thrombus formation along the lateral wall of the left ventricle . Note that the chordae tendineae to the anterior mitral leaflet are entrapped by the thrombus . (Right) Four-chamber view LGE MR image of the same patient with HES shows the characteristic intense subendocardial enhancement with an overlying dark thrombus. The asymmetry is somewhat atypical for this disorder.

(Left) Four-chamber view LGE MR with a long inversion time (600 ms) shows biapical thrombi in a patient with dilated cardiomyopathy. Note that the cavity size is not decreased. Although thrombi may have adjacent enhancement when attached to areas of prior infarction, the pattern is different from that of HES. (Right) Threechamber (left) and 2-chamber (right) MR cine images of a patient with left ventricular noncompaction show the abnormal apical trabeculations typical in this entity.

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(Left) Four-chamber view MR cine image of a patient with the apical variant of hypertrophic cardiomyopathy (HCM) shows filling in of the left ventricular apex, similar to the appearance of HES. There is also a small aneurysm at the apex, containing a tiny clot . Apical aneurysm formation is a known complication of apical HCM. (Right) Fourchamber view LGE MR (same patient) shows patchy apical mid-myocardial enhancement in a typical HCM pattern, which is different from the pattern of HES.

Cardiac Sarcoidosis Key Facts Terminology  Cardiac sarcoidosis (CS) Imaging  Left ventricular free wall and basilar septum are most common sites of involvement  Septal involvement likely explains common presentation of complete heart block  Abnormal enhancement on late gadolinium enhancement (LGE) MR images in nonischemic pattern has highest sensitivity/specificity of available noninvasive imaging studies  Distribution of abnormal LGE MR is most commonly subepicardial or midmyocardial and along RV border of interventricular septum  Presence of abnormal LGE has been reported to confer 9x ↑ risk of major adverse cardiac events and 11.5x ↑ risk of sudden death Top Differential Diagnoses  Arrhythmogenic right ventricular dysplasia (ARVD) o Ventricular aneurysms, focal wall motion abnormalities, and abnormal LGE MR may be seen in both CS and ARVD  Myocarditis o Overlaps with sarcoid on imaging as CS is a form of (granulomatous) myocarditis  Myocardial infarction o Coronary-type LGE MR pattern is seen in ˜ 10% of CS cases Clinical Issues  Associated with poorer prognosis compared to sarcoidosis that does not involve heart  Accounts for 13-25% of deaths from sarcoidosis  Corticosteroids are mainstay of therapy

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(Left) Short-axis late gadolinium enhancement (LGE) image in a patient with cardiac sarcoidosis (CS) demonstrates abnormal enhancement of the right ventricular side of the septum , a common site of involvement in this disorder. (Right) Four-chamber view LGE image of the same patient better demonstrates the extent of the abnormal contrast enhancement of the septum . Note that this is a noncoronary pattern of uptake, as is usually the case in this entity.

(Left) Short-axis LGE image of a patient with CS shows transmural abnormal enhancement of the anterior, anteroseptal, and anterolateral walls . Note the abnormal enhancement of the anterior right ventricular wall . In ˜ 10-15% of patients with CS, the enhancement may mimic a coronary artery disease pattern with a subendocardial component. (Right) Short-axis T2WI FSE MR of the same slice location shows increased T2 signal indicative of edema, showing that the inflammatory process is acute. P.7:43

TERMINOLOGY Abbreviations  Cardiac sarcoidosis (CS) Definitions  Sarcoidosis: Chronic, multisystemic disease of unknown etiology characterized by presence of noncaseating granulomas in affected organs, most commonly lungs o Cardiac involvement occurs in 5% of patients clinically, but much higher percentage (˜ 25%) is found at autopsy IMAGING General Features  Best diagnostic clue 580

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Cardiac involvement should be suspected in known sarcoid patients with complete heart block or frequent ventricular arrhythmias

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Location o Left ventricular free wall and basilar septum are most common sites of involvement  Septal involvement likely explains common presentation of complete heart block  Size o Granuloma formation may be microscopic or macroscopic  Morphology o Granulomatous infiltration may produce nodules within myocardium  As the disease progresses, this may evolve into scarring that is seen as thinning of myocardium, resulting in aneurysm formation  Occasionally, mild thickening of myocardium is noted and may resemble asymmetric hypertrophy Imaging Recommendations  Best imaging tool o Cardiac MR  Abnormal enhancement on late gadolinium enhancement (LGE) MR images in nonischemic pattern has highest sensitivity/specificity of available noninvasive imaging studies  Protocol advice o Cine MR imaging to evaluate overall left ventricular and right ventricular functions and look for localized wall motion abnormalities o High-resolution LGE MR imaging to detect subtle regions of fibrosis  Single-shot techniques may be substituted in arrhythmic patients, with slight decrease in sensitivity o FDG PET scanning may be useful in patients with pacemakers/defibrillators Image-Guided Biopsy  Endomyocardial biopsy is useful when positive, demonstrating noncaseating granulomas consistent with CS  Very low sensitivity (˜ 20%) due to sampling errors, as CS is often patchy and may not involve segments commonly biopsied Radiographic Findings  Chest radiographs are helpful in demonstrating common findings of pulmonary involvement, including bilateral hilar and mediastinal adenopathy o More advanced cases may show significant interstitial lung disease progressing to honeycombing  Uncommonly, CS may result in cardiomegaly and signs of heart failure Echocardiographic Findings  Small granulomas are usually not visible and so cannot reliably establish or exclude the diagnosis  Granulomatous involvement of myocardium with scar formation may appear hyperechoic on echocardiography MR Findings  T2WI FS o High signal intensity indicates presence of myocardial edema due to inflammation in acute phase o Hyperintense regions are most often seen in midmyocardium or subepicardium and parallel areas of abnormal delayed enhancement  MR cine o Wall motion abnormalities in noncoronary distribution may be seen o Occasionally, left ventricular or right ventricular wall aneurysms may be seen secondary to ventricular wall thinning  LGE enhancement o Distribution of abnormal LGE MR is mostly subepicardial or midmyocardial and along RV border of interventricular septum  In ˜ 10% of cases, LGE MR pattern may be subendocardial, mimicking infarct o Abnormal LGE has been reported to confer 9x increased risk of major adverse cardiac events and 11.5x increased risk of sudden death o Steroid therapy has been demonstrated to reduce size of hyperenhancement on LGE MR Nuclear Medicine Findings  Segmental defects are seen on scintigraphy with thallium-201 and FDG PET, which correspond to areas of granulomatous replacement  Defects decrease on exercise stress thallium imaging, a phenomenon known as reverse distribution 581

Diagnostic Imaging Cardiovascular o Helps differentiate from defects secondary to coronary artery disease DIFFERENTIAL DIAGNOSIS Arrhythmogenic Right Ventricular Dysplasia (ARVD)  Ventricular aneurysms and focal wall motion abnormalities may be seen in both, as may abnormal LGE MR  Adenopathy and left ventricular septal involvement are more typical of CS than of ARVD  ARVD usually presents with significant right ventricular dysfunction, whereas CS more commonly shows left ventricular or combined dysfunction P.7:44

Myocarditis  Inflammatory infiltrate of myocardium with necrosis &/or degeneration of adjacent myocytes, usually viral in origin  Abnormal enhancement on LGE MR imaging is typically subepicardial in lateral wall but may occur anywhere  Overlaps with sarcoid on imaging as CS is a form of (granulomatous) myocarditis Acute Myocardial Infarction  Clinical presentation differs with chest pain, ECG abnormalities, and elevated troponin  LGE MR shows hyperenhancement in ischemic pattern o Subendocardial predominant pattern (with variable transmural extent) conforming to coronary artery territory o Coronary-type LGE MR pattern is seen in ˜ 10% of CS cases PATHOLOGY General Features  Etiology o Exaggerated immune response to variety of antigens that cause CD4 cell accumulation and release of inflammatory cytokines, leading to granuloma formation o Infectious and environmental agents have been implicated as potential antigens  Genetics o Genetic factors may play a role  Polygenic inheritance pattern Gross Pathologic & Surgical Features  Noncaseating epithelioid granulomas are seen  Granulomas may involve pericardium, myocardium, or endocardium o Myocardium is most frequently involved Microscopic Features  Microscopic examination reveals T lymphocytes and mononuclear phagocytes, which initially are seen at sites of inflammation  As disease progresses, there is granuloma formation consisting of aggregated macrophages, epithelioid cells, and giant cells  Dense band of fibroblasts, collagen, and proteoglycans usually encases aggregate of inflammatory cells CLINICAL ISSUES Presentation  Most common signs/symptoms o Majority of patients are asymptomatic o Common presentations  Conduction abnormalities, most commonly complete heart block  Sustained or nonsustained ventricular tachycardia (2nd most common presentation)  Other signs/symptoms o Mitral valve regurgitation is most common valvular abnormality seen o Congestive heart failure may also be seen  2nd most common cause of sarcoid-related mortality after sudden death due to conduction abnormalities Demographics  Ethnicity o In United States, African Americans have 3-4x greater risk compared with whites o Higher incidence of concurrent involvement of myocardium in certain races, e.g., Japanese (up to 50% of patients with sarcoidosis may have cardiac involvement) Natural History & Prognosis 582

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Cardiac involvement of sarcoidosis is associated with poorer prognosis compared to sarcoidosis that does not involve heart  Accounts for 13-25% of deaths from sarcoidosis  Mortality rate may exceed 40% at 5 years and 55% at 10 years Treatment  Corticosteroids are mainstay of therapy o Multiple series appear to show benefit, but no randomized controlled trials have documented efficacy  Immunosuppressive therapy in steroid-intolerant patients  Antiarrhythmic therapy/pacemaker placement depending on electrophysiologic abnormalities DIAGNOSTIC CHECKLIST Consider  CS in patient with known pulmonary sarcoid presenting with complete heart block or frequent ventricular beats SELECTED REFERENCES 1. Bussinguer M et al: Cardiac sarcoidosis: diagnosis and management. Curr Treat Options Cardiovasc Med. 14(6):65264, 2012 2. Steckman DA et al: Utility of cardiac magnetic resonance imaging to differentiate cardiac sarcoidosis from arrhythmogenic right ventricular cardiomyopathy. Am J Cardiol. 110(4):575-9, 2012 3. Patel MR et al: Detection of myocardial damage in patients with sarcoidosis. Circulation. 120(20):1969-77, 2009 4. Borchert B et al: Utility of endomyocardial biopsy guided by delayed enhancement areas on magnetic resonance imaging in the diagnosis of cardiac sarcoidosis. Clin Res Cardiol. 96(10):759-62, 2007 5. Tadamura E et al: Images in cardiovascular medicine. Multimodality imaging of cardiac sarcoidosis before and after steroid therapy. Circulation. 113(20):e771-3, 2006 6. Smedema JP et al: The additional value of gadolinium-enhanced MRI to standard assessment for cardiac involvement in patients with pulmonary sarcoidosis. Chest. 128(3):1629-37, 2005 7. Tadamura E et al: Effectiveness of delayed enhanced MRI for identification of cardiac sarcoidosis: comparison with radionuclide imaging. AJR Am J Roentgenol. 185(1):110-5, 2005 P.7:45

Image Gallery

(Left) Short-axis cine (top) and LGE (bottom) images in a patient with CS show marked thinning of the lateral left ventricular wall on the cine image and transmural enhancement on the LGE image . Note also the localized left ventricular dilatation. (Right) Three-chamber cine (top) and LGE (bottom) images in the same patient better demonstrate the localized aneurysm of the lateral basal wall . Note the enhancement of the aneurysm wall and other small foci of enhancement .

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(Left) Short-axis LGE image of a patient with proven CS demonstrates enhancement of the septum and right ventricular free wall . Note also that the right ventricle is dilated. (Right) Short-axis LGE image of a patient with arrhythmogenic right ventricular cardiomyopathy demonstrates findings similar to those sometimes seen in CS. Note the dilated right ventricle with abnormal enhancement of the right ventricular free wall.

(Left) Short-axis (top) and 3-chamber view (bottom) LGE images in a patient with viral myocarditis demonstrate epicardial enhancement of the lateral wall , a pattern characteristically described with parvovirus B19. (Right) Short-axis (top) and 4-chamber (bottom) LGE images of another patient with viral myocarditis show abnormal septal enhancement . This pattern clearly overlaps with findings often seen in CS. Note also the small focus of enhancement in the lateral wall .

Cardiac Amyloidosis Key Facts Terminology  Amyloidosis: Heterogeneous group of diseases characterized by extracellular accumulation of abnormal fibrillar protein deposits (amyloid) Imaging  Diffuse process that can involve nearly any portion of heart (myocardium, atria, small vessels, conduction system, and heart valves)  Concentric increase in wall thickness of left ventricle and sometimes right ventricle  Increased echogenicity of myocardium on echocardiogram described as sparkling or granular  Cardiac MR is best imaging modality to characterize myocardial pathology in amyloidosis and distinguish it from other causes of restrictive cardiomyopathy 584

Diagnostic Imaging Cardiovascular o Diffuse pattern of late gadolinium enhancement (circumferential, subendocardial, or more diffuse) Top Differential Diagnoses  Hypertrophic cardiomyopathy  Hypertensive heart disease  Sarcoidosis  Glycogen storage diseases Pathology  Types of amyloidosis that affect heart o Immunoglobulin light chain amyloidosis (AL) o Familial transthyretin-related amyloidosis (ATTR) o Senile systemic amyloidosis (wild-type TTR) o Secondary amyloidosis (AA) o Isolated atrial amyloidosis (atrial natriuretic peptide) Clinical Issues  Prognosis depends on type of amyloid and extent of cardiac and systemic involvement

(Left) Short-axis MR cine image in a 70-year-old woman with progressive congestive heart failure shows a concentric increase in left ventricular (LV) wall thickness (maximum of 15 mm) with a trace pericardial effusion. (Right) Shortaxis late gadolinium enhancement (LGE) image (same patient) shows a diffuse pattern of LGE in a mostly subendocardial and circumferential distribution involving the basal LV and right ventricle (RV) , typical of cardiac amyloidosis. Endomyocardial biopsy showed AL amyloidosis.

(Left) Four-chamber view MR cine view shows moderate increase in LV wall thickness with severe biventricular systolic dysfunction (LVEF = 31%; RVEF = 28%) with qualitative evidence of significant mitral and tricuspid regurgitation . (Right) Four-chamber view late gadolinium enhancement image shows extensive diffuse LV 585

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Diagnostic Imaging Cardiovascular RV late enhancement. Note that the myocardium is poorly nulled, which is typical of cardiac amyloidosis. P.7:47

TERMINOLOGY Definitions  Amyloidosis: Heterogeneous group of diseases characterized by extracellular accumulation of abnormal fibrillar protein deposits (amyloid)  Cardiac involvement can result in infiltrative cardiomyopathy IMAGING General Features  Best diagnostic clue o Restrictive cardiomyopathy in advanced stages  Concentric increase in left ventricular (LV) and sometimes right ventricular (RV) wall thickness  Enlarged atria  Location o Diffuse process that can involve nearly any portion of heart (myocardium, atria, small vessels, conduction system, and heart valves) Echocardiographic Findings  Increase in LV and sometimes RV wall thickness o Increased echogenicity of myocardium described as speckled, sparkling, or granular o Restrictive filling pattern on pulsed-wave Doppler of mitral valve  Biatrial enlargement and infiltration of interatrial septum  Valvular leaflet thickening MR Findings  Concentric increase in LV and sometimes RV wall thickness  Biatrial enlargement and thickening of interatrial septum  Diffuse pattern of late gadolinium enhancement o Circumferential and typically subendocardial, though can be diffuse o Abnormal gadolinium kinetics  Increased clearance from blood pool  Heterogeneous myocardial signal on late-enhancement images leading to difficulty nulling the myocardium  Late gadolinium enhancement of atrial wall  Recent research shows abnormalities on T1 mapping sequences that correspond to expansion of extracellular volume fraction due to deposition of amyloid protein &/or fibrosis o Further clinical studies are necessary to validate diagnostic and clinical utility Imaging Recommendations  Best imaging tool o Cardiac MR is best imaging modality to characterize myocardial pathology in amyloidosis and distinguish it from other causes of restrictive cardiomyopathy  Diagnostic performance of cardiac MR in early stages of disease is unclear  Protocol advice o SSFP cine sequence to evaluate wall thickening and systolic function o Late gadolinium enhancement  Inversion times may be shorter than usual due to diffuse gadolinium retention in areas of infiltration  Often have to image earlier after gadolinium administration given abnormal kinetics (˜ 5 minutes) CT Findings  Cardiac CT can be used to exclude obstructive coronary artery disease in select patients DIFFERENTIAL DIAGNOSIS Hypertrophic Cardiomyopathy  Pattern of hypertrophy is most commonly asymmetric o Concentric variant can be difficult to distinguish from infiltrative process  Genetic condition which can be associated with increased risk of sudden death Hypertension 586

Diagnostic Imaging Cardiovascular  Typically associated with concentric increase in LV wall thickness in patient with documented hypertension  Diastolic dysfunction Sarcoidosis  Infiltrating, noncaseating granulomas  Bradyarrhythmias due to conduction system disease and ventricular arrhythmias due to myocardial involvement  Typically has nonischemic pattern of late gadolinium enhancement, T2 abnormalities in areas of active disease, and evidence of mediastinal adenopathy Glycogen Storage Diseases  Rare cause of infiltrative cardiomyopathy  Nonischemic patterns of late gadolinium enhancement have been described PATHOLOGY General Features  Etiology o Types of amyloidoses that can affect heart  Immunoglobulin light-chain amyloidosis (AL)  Deposition of insoluble monoclonal immunoglobulin light chains or light-chain fragments  Familial transthyretin-related amyloidosis (ATTR)  Deposition of mutant transthyretin protein  Senile systemic amyloidosis (wild-type TTR)  Deposition of normal TTR protein  Secondary amyloidosis (AA)  Deposition of amyloid fibrils derived from serum amyloid A; associated with inflammatory conditions (rheumatoid arthritis, infection)  Isolated atrial amyloidosis (atrial natriuretic peptide)  Amyloid protein derived from atrial natriuretic peptide  Genetics o Familial transthyretin-related amyloidosis  Autosomal dominant  > 70 mutations have been described in transthyretin protein P.7:48  4% of African American population is heterozygous for Val-122-Ile mutation Associated abnormalities o Systemic involvement is common in AL amyloidosis  Hepatic and renal involvement, neurologic involvement (carpal tunnel syndrome, neuropathy), macroglossia, dermatologic manifestation (easy bruising, periorbital purpura) o Renal involvement is seen in AA amyloidosis Staging, Grading, & Classification  Mayo Clinic staging of AL amyloidosis o Lower survival if elevated troponin T and NT-pro-BNP Gross Pathologic & Surgical Features  Definitive diagnosis depends on histologic confirmation of amyloid deposition  Endomyocardial biopsy is gold standard for diagnosis of cardiac involvement o May not be necessary if amyloid is demonstrated on noncardiac tissue and imaging findings are consistent with cardiac involvement o In AL amyloidosis, abdominal fat pad biopsy can be positive in > 70% Microscopic Features  Congo red stain with apple green birefringence under polarized light  Specific protein types can be identified using immunoelectron microscopy CLINICAL ISSUES Presentation  Most common signs/symptoms o Depend on type of amyloid and stage of cardiac involvement  Rapidly progressive congestive heart failure in advanced AL amyloidosis o Dyspnea is common; angina can be seen in absence of coronary artery disease 

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Diagnostic Imaging Cardiovascular o Arrhythmias, including atrial fibrillation and conduction system disease leading to bradyarrhythmias o Low voltage on electrocardiography  Other signs/symptoms o Systemic involvement is typically seen in AL amyloidosis Demographics  Age o Variable; depends on type of amyloid  Senile amyloidosis is typically seen after age of 60  Familial amyloidosis is most common after age of 40  Gender o Senile amyloidosis is almost exclusively seen in men o Isolated atrial amyloidosis may be more common in women  Epidemiology o Variable; depends on specific disease o In USA, AL type is most common cause of cardiac amyloidosis Natural History & Prognosis  Immunoglobulin light-chain amyloidosis o Poor prognosis with extensive cardiac involvement o Progressive disease without definitive treatment of plasma cell disorder  Familial transthyretin-related amyloidosis o Lower incidence of heart failure and better survival when compared to AL amyloidosis  Senile systemic amyloidosis o Median survival after onset of symptoms: ˜ 8 years  Secondary amyloidosis o Clinically significant heart failure is rare Treatment  Immunoglobulin light-chain amyloidosis o Definitive treatment targeting plasma cell dyscrasia  Chemotherapy and autologous stem cell transplant o Heart transplant followed by chemotherapy and stem cell transplant can be associated with improved survival in carefully selected subset of patients  Familial transthyretin-related amyloidosis o Definitive treatment involves liver transplant, which can be combined with heart transplant in subset of patients  Secondary amyloidosis o Treatment of underlying inflammatory condition  General management of congestive heart failure in cardiac amyloidosis o Diuretic therapy for volume overload o ACE inhibitors can be associated with hypotension, particularly in AL amyloidosis o Increased risk of digoxin toxicity secondary to binding of drug to amyloid fibrils o Pacemaker in setting of symptomatic bradycardia or conduction system disease o Anticoagulation is generally recommended in patients with atrial fibrillation DIAGNOSTIC CHECKLIST Consider  Echocardiogram is most common initial diagnostic test  Cardiac MR shows excellent diagnostic accuracy in patients with abnormalities on echocardiogram and can be useful to evaluate for other causes of cardiomyopathy SELECTED REFERENCES 1. Bradshaw SH et al: Cardiac amyloidosis: what are the indications for transplant? Curr Opin Cardiol. 27(2):143-7, 2012 2. Mongeon FP et al: Quantification of extracellular matrix expansion by CMR in infiltrative heart disease. JACC Cardiovasc Imaging. 5(9):897-907, 2012 3. Gertz MA et al: Transplantation for amyloidosis. Curr Opin Oncol. 19(2):136-41, 2007 4. vanden Driesen RI et al: MR findings in cardiac amyloidosis. AJR Am J Roentgenol. 186(6):1682-5, 2006 5. Falk RH: Diagnosis and management of the cardiac amyloidoses. Circulation. 112(13):2047-60, 2005 6. Kwong RY et al: Cardiovascular magnetic resonance in cardiac amyloidosis. Circulation. 111(2):122-4, 2005 7. Maceira AM et al: Cardiovascular magnetic resonance in cardiac amyloidosis. Circulation. 111(2):186-93, 2005 8. Dispenzieri A et al: Serum cardiac troponins and N-terminal pro-brain natriuretic peptide: a staging system for primary systemic amyloidosis. J Clin Oncol. 22(18):3751-7, 2004 588

Diagnostic Imaging Cardiovascular 9. Gertz MA et al: Primary systemic amyloidosis. Curr Treat Options Oncol. 3(3):261-71, 2002 P.7:49

Image Gallery

(Left) Curved MPR cardiac CT shows no evidence of left anterior descending disease in a 61-year-old man with typical angina. The remaining coronary arteries were also normal. (Right) Four-chamber view cardiac CT shows a moderate increase in LV wall thickness in the absence of a history of hypertension. Subsequent cardiac MR showed diffuse LGE consistent with cardiac amyloidosis. Bone marrow biopsy confirmed plasma cell dyscrasia. Amyloidosis can be associated with small vessel disease.

(Left) Three-chamber view echocardiogram shows a concentric increase in LV wall thickness with increased echogenicity of the myocardium described as a speckled appearance , which is seen in cardiac amyloidosis. (Right) Pulsed-wave Doppler of the mitral valve inflow shows a restrictive filling pattern with an elevated E wave and a diminished A wave . This pattern is indicative of elevated filling pressures and can be seen in a variety of cardiomyopathies, including cardiac amyloidosis.

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(Left) Short-axis LGE image shows patchy areas of LGE involving the basal inferolateral wall in an epicardial distribution in a 76-year-old man with heart failure and mild left ventricular hypertrophy. (Right) Four-chamber view LGE image shows evidence of biatrial LGE involving the interatrial septum and superior aspect of the right atrium . Small bowel biopsy showed evidence of wild-type TTR, consistent with senile amyloidosis.

Left Ventricular Noncompaction Key Facts Terminology  Left ventricular noncompaction (LVNC)  Cardiomyopathy characterized by excessive left ventricular trabeculation  Thought to be due to arrest of normal embryologic process of myocardial compaction  Results in persistence of multiple prominent ventricular trabeculations and deep intertrabecular recesses Imaging  Predominantly involves midventricle to apex of left ventricle  Echocardiographic findings/criteria o End-systolic ratio of noncompacted to compacted layers > 2:1 on short-axis imaging o Predominant location of pathology: Mid-lateral, mid-inferior, and apex of left ventricle o Color Doppler evidence of deep perfused intertrabecular recesses o Coexisting cardiac abnormalities are absent (isolated LVNC)  MR findings o > 2.3:1 ratio of noncompacted to compacted myocardium at end-diastole on cine MR o Late gadolinium enhancement MR may demonstrate subendocardial hyperenhancement corresponding to myocardial fibrosis Top Differential Diagnoses  Apical hypertrophic cardiomyopathy  Dilated cardiomyopathy  Left ventricular thrombus Diagnostic Checklist  Important to evaluate for complicating/confounding thrombus

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(Left) Oblique graphic shows extensive trabeculations within the left ventricle and thinning of the underlying compact myocardium. There is predominant involvement of the left ventricular apex with sparing of the basal segments. (Right) Vertical long-axis (2-chamber) MR cine shows the left ventricle in a patient with left ventricular noncompaction. Note the extensive hypertrabeculation at the apex , which results in a 2-layered appearance of the myocardium.

(Left) Three-chamber view MR cine (same patient) demonstrates the excessive trabeculations at the left ventricular apex . In many cases, there is predominant involvement of the lateral and inferior walls, beginning at the midventricular level and extending to the apex. (Right) Short-axis MR cine image (same patient) demonstrates the diagnostic finding of a > 2.3:1 ratio of the thickness of the noncompacted to compacted myocardium. Note that diastolic phase images are used on MR. P.7:51

TERMINOLOGY Abbreviations  Left ventricular noncompaction (LVNC) Synonyms  Isolated noncompaction of ventricular myocardium  Left ventricular hypertrabeculation  Spongy myocardium Definitions  Distinct cardiomyopathy characterized by excessive left ventricular trabeculation  Thought to be due to arrest of normal embryologic process of myocardial compaction 591

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Results in persistence of multiple prominent ventricular trabeculations and deep intertrabecular recesses o LVNC is being increasingly recognized as distinct myocardial phenotype with heterogeneous genetic profile and variable course o Termed isolated LVNC when unaccompanied by other structural heart disease IMAGING General Features  Best diagnostic clue o Excessive trabeculation at left ventricular apex with delaminated appearance of myocardium into 2 layers  Location o Predominantly involves midventricle to apex of left ventricle  Lateral and inferior walls show greatest involvement Imaging Recommendations  Best imaging tool o Echocardiography has been traditionally utilized o Cardiac MR plays increasingly important role and will likely become imaging modality of choice  Protocol advice o MR studies should include late gadolinium enhancement imaging with long inversion time (˜ 600 milliseconds) to exclude thrombus  Echocardiographic findings/criteria o End-systolic ratio of noncompacted to compacted layers > 2:1 on short-axis imaging is suggestive o Predominant location of pathology: Mid-lateral, mid-inferior, and apex of left ventricle o Color Doppler evidence of deep perfused intertrabecular recesses o Coexisting cardiac abnormalities are absent (isolated LVNC) MR Findings  > 2.3:1 ratio of noncompacted to compacted myocardium at end-diastole on short-axis cine MR or long axis views for apical segments o Some studies also evaluate ratio of total trabeculated left ventricular mass to total left ventricular mass  > 20% of trabeculated mass is abnormal and specific for LVNC  Late gadolinium enhancement MR may demonstrate subendocardial hyperenhancement corresponding to myocardial fibrosis o Extent of abnormal enhancement correlates with disease severity  Subendocardial perfusion defects may be seen on 1st-pass perfusion imaging CT Findings  Findings on gated CTA are similar to those on cine MR Radiographic Findings  Cardiomegaly and pulmonary edema can be seen in severely afflicted individuals DIFFERENTIAL DIAGNOSIS Apical Hypertrophic Cardiomyopathy  Characterized by abnormal apical thickening that can mimic prominent trabeculations  Often complicated by aneurysm formation Dilated Cardiomyopathy  Normal apical trabeculations may be spread apart and appear more prominent Left Ventricular Thrombus  Usually adjacent to infarcted myocardium PATHOLOGY General Features  Etiology o Arrest in trabecular remodeling, which normally occurs during 8-12 weeks of fetal life  Normal compaction involves transformation of large intertrabecular spaces into capillaries, as well as evolution of the coronary circulation  Genetics o Both familial and sporadic forms of noncompaction have been described o Familial recurrence varies widely: 18-50%  Autosomal dominant inheritance is more common than X-linked  Genetic heterogeneity is common, with lack of specific genotype-phenotype association 592

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Sarcomere protein gene mutations are common and shared with hypertrophic and dilated cardiomyopathies  Many pediatric cases show X-linked patterns of inheritance associated with mutation of TAZ gene  This gene maps to Xq28 chromosome  Results in wide spectrum of severe X-linked cardiomyopathic phenotypes, including Barth syndrome  TAZ mutation is not found in adult cases Associated abnormalities o Intraventricular thrombus formation due to slow blood movement within heavily trabeculated regions of left ventricle o Ventricular and supraventricular arrhythmias o Biventricular noncompaction can occur with variable involvement of right ventricle  Right ventricular involvement has been reported in up to 50% of patients in some series o Congenital cardiac anomalies (not isolated LVNC)  Obstruction of right or left ventricular outflow tract  Complex cyanotic congenital heart disease P.7:52

o Subendocardial fibroelastosis Gross Pathologic & Surgical Features  Excessive trabeculation of left ventricle that predominantly involves apex and mid ventricle o May also involve right ventricle to lesser degree  Areas of subendocardial ischemia have been demonstrated during postmortem evaluation of individuals with severe noncompaction Microscopic Features  Interstitial fibrosis of endomyocardium is commonly seen CLINICAL ISSUES Presentation  Most common signs/symptoms o Clinical manifestations are highly variable depending on severity of left ventricular involvement  Individuals with mild forms of LVNC may remain asymptomatic  Early series of symptomatic patients likely overestimated prevalence of complications and adverse outcomes o Congestive heart failure  Both systolic and diastolic ventricular dysfunction have been described  Mean ejection fractions as low as 33% have been reported in some published series  Restrictive hemodynamics by cardiac catheterization may be present o Cardiac arrhythmias  Atrial fibrillation has been reported in up to 35% of individuals  Ventricular tachyarrhythmias have been reported in up to 50% of individuals  Paroxysmal supraventricular tachycardia and complete heart block have also been reported  Nonspecific resting ECG abnormalities have been frequently described (> 80%)  Inverted T waves, ST segment changes, axis shifts, intraventricular conduction abnormalities, and atrioventricular block o Thromboembolic events  Thought to be related to development of thrombi within prominent ventricular trabeculations due to sluggish blood flow  Reported incidence varies widely: 4-40%  Cerebrovascular accidents, transient ischemic attacks, pulmonary embolism, and mesenteric infarction have all been described in patients with LVNC  Atrial fibrillation and impaired systolic function have likewise been implicated in development of systemic emboli  Other signs/symptoms o Facial dysmorphisms amongst children have been rarely described  Prominent forehead, low-set ears, strabismus, high-arched palate, micrognathia Demographics  Age 593

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Congenital anomaly that is present at birth in most cases  Minority of cases appear later in life

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Gender o Slight male predominance according to largest reported series  Epidemiology o Median age at diagnosis is 7 years  Range: 1-22 years o 0.014% prevalence for all patients referred for echocardiography Natural History & Prognosis  60% of patients have either died or undergone cardiac transplantation within 6 years of diagnosis in 1 large series Treatment  Anticoagulation for prevention of systemic embolism o Not needed in patients with sinus rhythm and normal systolic function  Standard heart-failure therapy (afterload reduction, angiotensin-receptor blockers, etc.) as needed  Cardioverter-defibrillator implantation o Used in patients with syncope, symptomatic ventricular arrhythmias, or severely impaired left ventricular function  Orthotopic heart transplant  Metabolic cocktail for individuals with underlying mitochondrial myopathies DIAGNOSTIC CHECKLIST Image Interpretation Pearls  Most helpful finding is noncompacted to compacted ratio of > 2.3:1 on diastolic short-axis cine MR in several segments Reporting Tips  Important to evaluate for complicating/confounding thrombus SELECTED REFERENCES 1. Nucifora G et al: Myocardial fibrosis in isolated left ventricular non-compaction and its relation to disease severity. Eur J Heart Fail. 13(2):170-6, 2011 2. Oechslin E et al: Left ventricular non-compaction revisited: a distinct phenotype with genetic heterogeneity? Eur Heart J. 32(12):1446-56, 2011 3. Dodd JD et al: Quantification of left ventricular noncompaction and trabecular delayed hyperenhancement with cardiac MRI: correlation with clinical severity. AJR Am J Roentgenol. 189(4):974-80, 2007 4. Weiford BC et al: Noncompaction of the ventricular myocardium. Circulation. 109(24):2965-71, 2004 5. Pignatelli RH et al: Clinical characterization of left ventricular noncompaction in children: a relatively common form of cardiomyopathy. Circulation. 108(21):2672-8, 2003 6. Jenni R et al: Echocardiographic and pathoanatomical characteristics of isolated left ventricular non-compaction: a step towards classification as a distinct cardiomyopathy. Heart. 86(6):666-71, 2001 7. Oechslin EN et al: Long-term follow-up of 34 adults with isolated left ventricular noncompaction: a distinct cardiomyopathy with poor prognosis. J Am Coll Cardiol. 36(2):493-500, 2000 P.7:53

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(Left) Four-chamber view MR cine image shows involvement of both ventricles. Although the subject of some disagreement due to a lack of clear diagnostic criteria, right ventricular involvement is suspected in up to 40% of patients. (Right) Four-chamber view late gadolinium enhancement image (same patient) shows subendocardial enhancement consistent with fibrosis at the apex . This finding of abnormal enhancement is correlated with ventricular function impairment.

(Left) Short-axis echocardiogram (same patient) obtained at the apex during systole reveals an abnormal noncompacted to compacted myocardial ratio (> 2:1). Note that echocardiographic diagnosis is made using systolic images. (Right) Short-axis MR cine (same patient) demonstrates an abnormal ratio (> 2.3:1) of noncompacted to compacted myocardium in diastole. Note the image clarity, making diagnosis of the abnormality relatively straightforward.

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(Left) Three-chamber view MR cine image obtained post contrast demonstrates thrombi at the left ventricular apex. Thrombi may present a confusing appearance as they are isointense to muscle on pre-contrast cine MR images. They also are isoechoic on echocardiography and may be mistaken for trabeculations. (Right) Horizontal long-axis (4chamber) MR cine image shows the apical variant of hypertrophic cardiomyopathy, an entity occasionally mimicking noncompaction.

Chagas Disease Key Facts Terminology  Chagas heart disease, American trypanosomiasis Imaging  60-80% of infected cases do not progress to clinical abnormalities  Chagas cardiomyopathy is the most common clinical manifestation  Echocardiography, cine MR, and gated CTA (advanced clinical phase) show global biventricular dysfunction with segmental akinesis and aneurysms, usually involving left ventricular apex and inferolateral walls  Left ventricular wall thinning is also noted, particularly involving apex o Results in apical aneurysm (vortex lesion), a characteristic feature of Chagas heart disease  Extent of myocardial fibrosis shown on LGE MR correlates with global and regional function assessments and may reveal subclinical Chagas heart disease  Prevalence of fibrosis on LGE MR images varies with disease severity o Typically affects apex and inferolateral regions of left ventricle o Indeterminate/asymptomatic phase: 20% positive on LGE MR o Symptomatic cardiomyopathy patients: 85% positive on LGE MR o Cardiomyopathy patients with ventricular tachycardia: 100% positive on LGE MR Top Differential Diagnoses  Myocarditis  Ischemic cardiomyopathy  Apical hypertrophic cardiomyopathy  Takotsubo cardiomyopathy  Congenital aneurysm

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(Left) Posteroanterior radiograph shows global cardiomegaly and clear lungs in a patient with chronic Chagas cardiomyopathy. There is no evidence of pulmonary edema or pleural effusion. Chagas disease is a common cause of heart failure in countries where it is endemic. (Right) Long-axis vertical 2-chamber late gadolinium enhancement (LGE) MR image demonstrates abnormal enhancement of the apex, a finding indicative of myocardial fibrosis in a patient with Chagas cardiomyopathy.

(Left) Three-chamber view LGE MR image of another patient with Chagas disease shows abnormal enhancement of the apex and also of the inferolateral wall at the basal level . These are the areas of the heart most commonly involved by Chagas cardiomyopathy. (Right) Long-axis gross pathology specimen shows a typical vortex aneurysm at the left ventricular apex, a finding characteristic of Chagas cardiomyopathy. P.7:55

TERMINOLOGY Synonyms  Chagas heart disease, American trypanosomiasis Definitions  Disease resulting from infection by protozoan parasite Trypanosoma cruzi, which is transmitted through feces of infected bloodsucking insects in endemic areas of Latin America IMAGING General Features  Best diagnostic clue o Myocardial fibrosis on late gadolinium enhancement (LGE) MR typically affecting apex and inferolateral regions of left ventricle (LV) in heart failure patient from an endemic region 597

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Also frequently noted is thinning of LV wall, particularly involving apex, resulting in apical aneurysm (vortex lesion), a characteristic feature of Chagas heart disease

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Location o Apex and inferolateral segment of LV  Morphology o 60-80% of infected cases do not progress to clinical abnormalities  Termed the indeterminate chronic stage  Most will have preserved LV morphology and function, but 15-20% may show abnormal results on LGE MR o Progressive chronic disease is seen in 20-40% of cases  Most common clinical manifestation: Chagas cardiomyopathy  Dilated cardiomyopathy with global cardiac enlargement Imaging Recommendations  Best imaging tool o LGE MR may demonstrate predominantly midwall and subepicardial hyperenhancement areas encompassing multiple coronary territories (nonischemic pattern) o Echocardiography, cine MR, and gated CTA (advanced clinical phase) show global biventricular dysfunction with segmental akinesis and aneurysms, usually involving LV apex and inferolateral walls  Protocol advice o LGE MR should be included in any cardiac MR protocol for cardiomyopathy evaluation o Delayed-enhancement imaging patterns may provide specific diagnosis of cardiomyopathies Radiographic Findings  Global cardiomegaly, pulmonary vascular congestion, pulmonary edema Echocardiographic Findings  First-line tool for morphologic and functional evaluation  Increased LV volumes  Segmental or global wall motion abnormalities  Apical aneurysm and intracavitary thrombus MR Findings  MR cine o Cine imaging is useful in demonstrating location, extent, and severity of global and regional systolic dysfunction  Dysfunction is often most severe in apex and lateral wall  LGE enhancement o Extent of myocardial fibrosis shown on LGE MR correlates with global and regional function assessments and may reveal subclinical Chagas heart disease  Prevalence of fibrosis on LGE MR images varies with disease severity  Indeterminate/asymptomatic phase: 20% positive on LGE MR  Symptomatic patients with cardiomyopathy: 85% positive on LGE MR  Cardiomyopathy patients with ventricular tachycardia: 100% positive on LGE MR o Fibrosis is seen as abnormal enhancement on LGE MR  Usually nonischemic pattern (midwall and subepicardial location in multiple coronary artery distributions)  Subendocardial enhancement mimicking CAD may be seen in small percentage of cases o LGE MR imaging with long inversion time (˜ 600 milliseconds) is most sensitive and specific technique for evaluation of thrombus CT Findings  Gated coronary CTA is occasionally useful in excluding significant coronary artery disease in selected Chagas patients with atypical chest pain Angiographic Findings  Typical LV apical aneurysm (vortex lesion)  Normal epicardial coronary arteries DIFFERENTIAL DIAGNOSIS Viral Myocarditis  Serologic tests for Trypanosoma cruzi are negative  Geographic history does not include endemic regions  Imaging in viral myocarditis often occurs in acute phase and frequently shows T2 signal abnormalities (edema) 598

Diagnostic Imaging Cardiovascular Ischemic Cardiomyopathy  May also produce apical aneurysm  LGE MR findings usually follow ischemic wavefront pattern (beginning in subendocardium and extending toward epicardium) in coronary artery distribution  Endocardial involvement is hallmark for ischemic lesions Apical Hypertrophic Cardiomyopathy  Often complicated by formation of apical aneurysm, which usually shows delayed enhancement  LV function is preserved Takotsubo Cardiomyopathy  A form of nonischemic cardiomyopathy in which there is sudden temporary dysfunction of myocardium P.7:56

o Dysfunction is manifested as apical dilatation or “ballooning”  Usually triggered by severe emotional stress Congenital Aneurysm  Imaging pattern may be indistinguishable from that of Chagas disease, showing fibrotic apical aneurysms o LGE MR is abnormal in 70%  Serologic tests for Trypanosoma cruzi are negative  Geographic history does not include endemic regions PATHOLOGY General Features  Etiology o Caused by flagellate protozoa Trypanosoma cruzi o Insect vectors of Chagas disease belong to Hemiptera order, Reduviidae family, and Triatominae subfamily (“kissing bugs”)  Associated abnormalities o Megaesophagus and megacolon Gross Pathologic & Surgical Features  Cardiomegaly with ventricular wall thinning/aneurysm formation Microscopic Features  Intracellular parasite multiplication → rupture of infected cells → inflammatory response → fibrosis  Cellular lesions mainly affect myocytes (causing myocytolysis) and nervous cells (leading to autonomic denervation)  Arteriolar dilatation with organized thrombi and severe diffuse fibrosis in watershed myocardial regions (LV apex and basal inferior LV wall) CLINICAL ISSUES Presentation  Most common signs/symptoms o Typically, arrhythmias, cardiac failure, thromboembolic phenomena, or sudden death o Atypical chest pain without evidence of coronary artery disease (15-20% of patients) o Chagas heart disease is the most frequent and serious manifestation of symptomatic chronic disease Demographics  Age o Symptomatic acute phases mainly occur in newborns or young children o Chronic Chagas cardiomyopathy is generally detected in 3rd-5th decades of life  Gender o Chronic cardiomyopathy occurs earlier and is more severe in males than in females  Epidemiology o In USA, according to estimates, 100,000-675,000 immigrants from Latin America are infected with Trypanosoma cruzi o Internationally, estimated 8-10 million people are infected in Latin America  200,000 new cases per year Natural History & Prognosis  Acute phase (1 week after initial infection) o Usually asymptomatic o Mortality in < 5% of cases  Death results from acute myocarditis &/or meningoencephalitis 599

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Chronic phase o Indeterminate form: No symptoms; normal ECG; normal radiological study of heart, esophagus, and colon  60-80% of patients in indeterminate phase remain asymptomatic and never develop chronic lesions o Clinical forms: Cardiac, digestive, and mixed  In endemic areas, Chagas heart disease is the most common cause of cardiomyopathy and is a leading cause of cardiovascular death of patients aged 30-50 years (21,000 deaths annually) o Independent prognostic factors in chronic Chagas disease  Cardiomegaly with impaired LV function (New York Heart Association class III/IV)  Nonsustained ventricular tachycardia Treatment  Acute phase: Always requires treatment with benznidazole; cures 100% of children < 2 years old and 60-70% of acutely infected older patients  Chronic cardiac phase o Diuretics, digitalis, angiotensin-converting enzyme inhibitors, and other standard heart failure therapies o Class III antiarrhythmic drugs (sotalol and amiodarone) o Anticoagulant treatment is justified in patients at risk for thromboembolic complications DIAGNOSTIC CHECKLIST Consider  Chagas disease in patients from endemic areas who present with new-onset heart failure Image Interpretation Pearls  Look for apical aneurysm and abnormal enhancement on LGE MR SELECTED REFERENCES 1. Peix A et al: Myocardial perfusion imaging and cardiac involvement in the indeterminate phase of chagas disease. Arq Bras Cardiol. 100(2):114-117, 2013 2. Buysschaert I et al: Stone heart or apical retraction and calcification in Chagas' cardiomyopathy. Eur Heart J Cardiovasc Imaging. 13(7):625, 2012 3. Mello RP et al: Delayed enhancement cardiac magnetic resonance imaging can identify the risk for ventricular tachycardia in chronic Chagas' heart disease. Arq Bras Cardiol. 98(5):421-30, 2012 4. Valdigem BP et al: Accuracy of epicardial electroanatomic mapping and ablation of sustained ventricular tachycardia merged with heart CT scan in chronic Chagasic cardiomyopathy. J Interv Card Electrophysiol. 29(2):119-25, 2010 5. Marcu CB et al: Chagas' heart disease diagnosed on MRI: the importance of patient “geographic” history. Int J Cardiol. 117(2):e58-60, 2007 P.7:57

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Diagnostic Imaging Cardiovascular (Left) Four-chamber view cine (left) and LGE MR images (right) in a patient with Chagas disease show apical thinning and ballooning on the systolic cine image . Enhancement is seen in the apex on the LGE MR image, a typical finding in Chagas disease. (Right) Two-chamber cine image (left) shows systolic apical ballooning in a patient with Takotsubo cardiomyopathy.

(Left) Short-axis (left) and 4-chamber (right) LGE MR images show nearly transmural lateral wall enhancement in a patient with Chagas disease. The lateral wall is commonly involved in this disorder, particularly at the base. There is also a small focus of enhancement of the anteroseptum . (Right) Short-axis (left) and 4-chamber (right) LGE MR images of a patient with viral myocarditis demonstrate subepicardial lateral wall enhancement in a pattern commonly seen in this entity.

(Left) Four-chamber cine (top) and LGE (bottom) MR images of a Chagas aneurysm show systolic outpouching on the cine image & enhancement of the apex on the LGE MR . (Right) Four-chamber view cine (top) and LGE (bottom) MR images of a patient with apical hypertrophic cardiomyopathy show an apical aneurysm . Note there are hypertrophic changes in the adjacent segments that produce cavity obliteration in the systolic cine image (top), a finding not seen in Chagas aneurysms.

Iron Overload Syndromes Key Facts Terminology  Iron overload syndromes  Primary form: Hemochromatosis o Autosomal recessive genetic disorder resulting in abnormal uptake of dietary iron  Secondary form: a.k.a. transfusional siderosis, secondary hemochromatosis, or transfusional iron overload 601

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Results from transfusion therapy of hereditary anemias characterized by ineffective erythropoiesis and hemolysis Thalassemia major and intermedia are most common worldwide

o Imaging  Low signal intensity of heart &/or liver on T2-weighted MR images should suggest diagnosis of iron overload  Excess iron levels can be displayed qualitatively on T2- or T2*-weighted MR images by hypointense signal changes in affected organs  T2* MR imaging can be used to quantify myocardial iron levels Top Differential Diagnoses  Hemochromatosis o Normal appearance of spleen and bone marrow suggests hemochromatosis  Transfusional iron overload o Abnormal amounts of iron accumulate 1st in reticuloendothelial system of liver, spleen, and bone marrow o Pancreas is initially spared but may be involved once reticuloendothelial system capacity is exceeded o Cardiac imaging findings are indistinguishable from those of hemochromatosis

(Left) Vertical long-axis (2-chamber) MR cine image of a patient with iron overload cardiomyopathy demonstrates abnormally low signal intensity in both the myocardium and the liver . The left ventricle is noted to be dilated, a finding commonly seen as the disease progresses. (Right) Axial NECT shows diffusely increased attenuation throughout the myocardium , consistent with extensive myocardial iron deposition. The left ventricular cavity is dilated, indicative of systolic dysfunction.

(Left) This SSFP MR cine image shows dark, amorphous artifact in the right ventricle , consistent with the dark banding artifact often seen with SSFP images. It is accentuated by the field inhomogeneity induced by the extensive 602

Diagnostic Imaging Cardiovascular iron present in the patient's tissues due to iron overload. (Right) Short-axis MR cine images (same patient) using SSFP (left) and GRE (right) sequences illustrate that the extensive banding artifact present on SSFP can often be circumvented by using GRE cine images. P.7:59

TERMINOLOGY Abbreviations  Iron overload syndromes (IOSs) Definitions  Primary form: Hemochromatosis o Autosomal recessive genetic disorder resulting in abnormal uptake of dietary iron o Progressive increase in total body iron stores with abnormal multiorgan parenchymal iron deposition  Not in reticuloendothelial system o Liver is primary site of abnormal iron deposition (leading to cirrhosis), although abnormal iron deposition can also occur in the heart (resulting in cardiomyopathy), pancreas (causing diabetes), or pituitary gland (resulting in hypogonadism)  Cirrhosis and hepatocellular carcinoma are greatly increased in frequency, along with heart failure in untreated cases  Secondary form: a.k.a. transfusional siderosis, secondary hemochromatosis, or transfusional iron overload o Results from transfusion therapy used in treatment of hereditary anemias characterized by ineffective erythropoiesis and hemolysis  Thalassemia major and intermedia are most common worldwide  Commonly require 1-2 transfusions/month beginning in early infancy  1 unit of packed cells contains 200-250 mg of iron (normal dietary uptake = 1-2 mg/d)  Cardiac involvement is most common cause of death, with 50% of patients dying before age 35 o Excessive iron is initially localized to reticuloendothelial system, but when storage is overwhelmed, iron is deposited in multiple tissues in pattern similar to hemochromatosis  Liver, spleen, and bone marrow are initially involved  Pancreas is initially spared but may become involved later as iron overload progresses  Cardiac involvement is most common cause of death IMAGING General Features  Best diagnostic clue o Low signal intensity of heart &/or liver on T2-weighted MR images should suggest diagnosis of iron overload o Excess iron levels can be displayed qualitatively on MR by hypointense signal changes in affected organs on T2- or T2*-weighted images o Echocardiography or MUGA scan can depict heart failure from iron overload in later stages of disease but do not identify etiology of disease  Location o Diffuse involvement of myocardium is characteristic, but inhomogeneous involvement occasionally occurs  Morphology o Although initially there may be restrictive cardiomyopathy produced, progressive cardiac iron loading results in dilated cardiomyopathy associated with systolic dysfunction Imaging Recommendations  Best imaging tool o T2* MR imaging can be used to quantify myocardial iron levels  Protocol advice o Breath-hold T2* GRE images with varying echo times (TEs) should be obtained to provide estimation of cardiac iron load o Standard short- and long-axis MR cine series should be obtained for evaluation of cardiac function CT Findings  NECT o Global hyperdensity of myocardium &/or liver may be noted 603

Diagnostic Imaging Cardiovascular MR Findings  T2* GRE o Can be done in a single breath-hold using GRE sequence with multiple TEs o Signal dropout with progressively longer TEs is greatly accelerated in patients with cardiac iron deposition o Iron deposition results in local field inhomogeneities that result in T2* shortening  Degree of T2* shortening is closely correlated with degree of iron deposition  Signal intensity measurements are typically obtained on short-axis midventricular images using region of interest positioned in the septum  Postprocessing with dedicated software facilitates calculation of myocardial T2* values from a plot of signal intensity relative to changing TE  T2* value < 10 milliseconds indicates severe iron loading (in 1 study, ˜ 89% of thalassemia patients with new-onset failure had T2* < 10 milliseconds)  T2* value of 10-20 milliseconds indicates mild to moderate iron loading  T2* value > 20 milliseconds is in normal range (normal mean: ˜ 40 milliseconds) o Efficacy of iron reduction treatment is also best assessed in this way  MR cine o Myocardial functional evaluations should show hyperdynamic contractility in unaffected anemic patients  Apparently normal function is abnormal in these patients and may be an early marker of cardiac involvement  Cine SSFP images may show reduced signal of the myocardium as they are relatively T2 weighted  Significant iron loading may be present before function becomes abnormal o However, once functional abnormalities develop, rapid progression to severe failure, arrhythmia, or death occurs Ultrasonographic Findings  Echocardiography may show restrictive physiology in initial stages and systolic dysfunction in later stages o Not recommended as screening tool (insensitive), because significant iron deposition may be present before echocardiographic abnormalities develop P.7:60

DIFFERENTIAL DIAGNOSIS Hemochromatosis  Both primary and secondary forms of IOS produce dark liver on MR images o However, there is poor correlation between hepatic and cardiac iron loading in either disorder  Normal appearance of spleen and bone marrow suggests hemochromatosis  Pancreas and pituitary involvement is seen early in hemochromatosis Transfusional Iron Overload  Abnormal amounts of iron accumulate 1st in reticuloendothelial system of liver, spleen, and bone marrow  Pancreas is initially spared but may be involved once reticuloendothelial system capacity is exceeded  Cardiac imaging findings are indistinguishable from those of hemochromatosis PATHOLOGY General Features  Etiology o Excess unbound iron deposited in the myocardium is highly cardiotoxic  Mitochondrial respiratory chain function is impaired, resulting in inadequate ATP production and eventual heart failure  Genetics o Hemochromatosis is autosomal recessive genetic disorder characterized by excessive uptake of dietary iron  80% of cases are due to mutation in HFE gene, most commonly p.C282Y mutation  Mutation leads to inadequate production of hepcidin, a protein that negatively modulates uptake of dietary iron  There is no excretory pathway in humans to eliminate excess iron, and thus iron build-up ensues  Patients homozygous for the gene show low penetrance for clinical disease, with probably < 3% developing significant disease 604

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Beta-thalassemia is the most common worldwide hereditary anemia resulting in transfusional iron overload  Homozygous patients will develop severe anemia early in life and require transfusions to survive  Iron loading predominantly results from transfusions but may also reflect down-regulation of hepcidin production related to ineffective erythropoiesis  This results in excessive dietary uptake of iron as well  Associated abnormalities o Hemochromatosis  Excessive liver deposition with development of cirrhosis, portal hypertension, and hepatocellular carcinoma  Excessive pancreatic iron deposition can result in type 1 diabetes mellitus  Abnormal deposition in skin results in bronze skin color  Pituitary hypogonadism o Transfusional iron overload/thalassemia  Severe anemia may be present if transfusion is inadequate  Frontal bossing (protuberance of frontal bones) may develop due to bone marrow expansion CLINICAL ISSUES Presentation  Most common signs/symptoms o Congestive heart failure in setting of significant cardiac involvement Demographics  Age o Hemochromatosis  Patients often present in their 40s and 50s  M>F o Transfusional siderosis  Patients often have cardiac involvement by early adulthood  Epidemiology o HFE-related primary form occurs predominantly in white populations of Northern European descent  Prevalence of p.C282Y gene homozygosity is 1:200 in this population Natural History & Prognosis  Once iron-related cardiac impairment has developed, the natural history is that of inexorable progression to heart failure and death Treatment  Transfusional iron overload is treated by chelation therapy using deferoxamine (intravenous or subcutaneous) often coupled with deferiprone orally  Hemochromatosis is treated by weekly phlebotomy until iron levels return to a normal range, and then bimonthly DIAGNOSTIC CHECKLIST Consider  IOSs when low cardiac or hepatic signal intensity is noted on T2-weighted images SELECTED REFERENCES 1. Siddique A et al: Review article: the iron overload syndromes. Aliment Pharmacol Ther. 35(8):876-93, 2012 2. Carpenter JP et al: On T2* magnetic resonance and cardiac iron. Circulation. 123(14):1519-28, 2011 3. Alexander J et al: HFE-associated hereditary hemochromatosis. Genet Med. 11(5):307-13, 2009 4. Kirk P et al: Cardiac T2* magnetic resonance for prediction of cardiac complications in thalassemia major. Circulation. 120(20):1961-8, 2009 5. Anderson LJ et al: Cardiovascular T2-star (T2*) magnetic resonance for the early diagnosis of myocardial iron overload. Eur Heart J. 22(23):2171-9, 2001 P.7:61

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(Left) Short-axis MR cine image of a mild transfusional ion overload syndrome (IOS) shows normal cardiac signal but very dark liver and spleen signals, as they are part of the reticuloendothelial system. Note that the pancreas is normal in signal intensity as expected early in transfusional IOS. In contrast, hemochromatosis often shows pancreatic but not splenic involvement. (Right) Short-axis MR cine of a severe transfusional IOS shows low pancreatic signal as well as cardiac and hepatic involvement.

(Left) Short-axis MR (left) and T2 FSE (right) images of a hemochromatosis patient show hepatic iron overload (low hepatic signal ) but normal cardiac signal intensity . There can be significant discrepancy in the degree of iron loading between the liver and the heart. (Right) Short-axis GRE images with varying echo times (4 ,7 , 10 , and 15 milliseconds) were obtained at a single slice location and show no signal dropout that would indicate abnormal iron deposition.

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(Left) Short-axis GRE images with varying echo times (2.4 , 5.4 , 8.3 , and 11.3 milliseconds) were obtained at a single slice location and show extensive signal dropout, which indicates abnormal iron deposition. (Right) Software analysis of the signal intensity of a selected region of the septum relative to the varying echo times allows calculation of the T2* value of the myocardium. The T2* value of 5.7 milliseconds is consistent with severe iron loading in a patient with thalassemia.

Takotsubo Cardiomyopathy Key Facts Terminology  Reversible left ventricular systolic dysfunction in absence of significant coronary artery stenosis  Also known as stress cardiomyopathy or apical ballooning syndrome  Classically described following periods of severe emotional or physical stress Imaging  Initial imaging test is usually echocardiogram or left ventriculogram during cardiac catheterization  Cardiac MR is best imaging modality to distinguish from other causes of left ventricular dysfunction, such as myocarditis or ischemic injury o Increased T2 signal (edema) in areas of hypokinesis o Areas of hypokinesis/akinesis can occur in various patterns o In 1 large series using cardiac MR in stress cardiomyopathy, apical ballooning was seen in 82%, biventricular hypokinesis in 34%, midventricular hypokinesis in 17%, and basal hypokinesis in 1%  Late gadolinium enhancement MR o Typically characterized by absence of significant late gadolinium enhancement o ˜ 9% can have minimal or subtle late gadolinium enhancement, particularly when lower signal intensity threshold is used Clinical Issues  Initial presentation can closely resemble that of acute myocardial infarction or acute coronary syndrome  In hospital, mortality range is 0-8%  Most patients typically recover left ventricular function within 4 weeks  Most common complication is heart failure ± pulmonary edema  Treatment is supportive using standard heart failure therapy

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(Left) Three-chamber view graphic shows the most common type of stress cardiomyopathy with severe hypokinesis of all apical segments resulting in apical ballooning. This results in a left ventricular (LV) shape resembling the Japanese octopus trap (takotsubo), which gave the entity its name. (Right) Vertical long-axis (2-chamber) MR cine image in systole shows a typical pattern of stress cardiomyopathy with akinesis of the mid to apical LV and normal contraction of the basal LV .

(Left) Vertical long-axis (2-chamber) late gadolinium enhancement (LGE) image of the LV shows no focal areas of abnormal LGE, which is typical in stress cardiomyopathy. (Right) Axial T1-weighted spin-echo sequence after gadolinium contrast is shown. The early global relative enhancement ratio is calculated by comparing pre- and postcontrast signal intensity in the myocardium normalized to skeletal muscle . In this case of stress cardiomyopathy, the ratio was abnormal at 9. P.7:63

TERMINOLOGY Synonyms  Stress cardiomyopathy  Apical ballooning syndrome Definitions  Reversible dysfunction of left ventricle (LV) in absence of significant coronary artery stenosis o Classically described following periods of severe emotional or physical stress  In recent prospective multicenter study, stressful trigger was identified in ˜ 70% of patients o Often accompanied by acute chest pain, ischemic ST segment abnormalities, and elevation of cardiac biomarkers 608

Diagnostic Imaging Cardiovascular IMAGING General Features  Best diagnostic clue o Regional wall motion abnormalities in setting of recent emotional or physical stress o In its most common variant, LV during systole resembles Japanese octopus pot, which has narrow mouth and large round base  Tako = octopus; tsubo = pot o Wall motion abnormalities often extend beyond a single coronary artery territory  Location o Most common variant features distinct apical ballooning with hypokinesis of mid to apical LV with preserved or hyperdynamic function at the base o Other patterns of LV dysfunction include biventricular, midventricular, and basal Imaging Recommendations  Best imaging tool o Initial imaging test is usually echocardiogram or left ventriculogram during cardiac catheterization o Cardiac MR is best imaging modality to distinguish from other causes of LV dysfunction, such as myocarditis or ischemic injury  Protocol advice o SSFP cine images in horizontal long-axis, vertical long-axis, and short-axis views o Short-axis T2-weighted images, which typically show evidence of myocardial edema in areas of hypokinesis o Late gadolinium enhancement (LGE) images can help differentiate from other causes of cardiomyopathy Nuclear Medicine Findings  Myocardial perfusion defects can be seen and may be related to microvascular dysfunction o Can be difficult to exclude ischemic heart disease on basis of nuclear myocardial perfusion CT Findings  Cardiac gated CTA o Absence of obstructive epicardial coronary artery disease o Functional assessment on multiphase reconstructions can show patterns of wall motion abnormalities consistent with stress cardiomyopathy MR Findings  T2WI FS o Increased T2 signal (edema) in areas of hypokinesis  Can be quantified by normalizing to skeletal muscle (following same protocol as for myocarditis)  MR cine o Areas of hypokinesis/akinesis can occur in various patterns  Findings in 1 large series using cardiac MR in stress cardiomyopathy  Apical ballooning in 82%  Biventricular hypokinesis in 34%  Midventricular hypokinesis in 17%  Basal hypokinesis in 1% o Pericardial effusion is seen in ˜ 40% of patients o LV thrombus is relatively uncommon finding  LGE enhancement o ˜ 9% can have minimal or subtle LGE, particularly when lower signal intensity threshold is used Echocardiographic Findings  Regional wall motion abnormalities (apical ballooning, biventricular, midventricular, and basal)  Can be difficult to appreciate extent and severity of regional wall motion abnormalities if acoustic windows are limited  Does not allow myocardial tissue characterization Angiographic Findings  Absence of significant coronary artery disease  Left ventriculogram shows typical regional wall motion abnormalities  Rarely, multivessel epicardial spasm is evident, which may be spontaneous or induced by ergonovine or acetylcholine infusion Image-Guided Biopsy 609

Diagnostic Imaging Cardiovascular  Endocardial biopsy shows nonspecific findings without evidence of myocardial necrosis DIFFERENTIAL DIAGNOSIS Acute Myocardial Infarction  Given presentation of chest pain, ischemic ECG changes, and regional wall motion abnormalities, coronary artery disease should always be excluded o Anatomic assessment with coronary angiography or cardiac CT  Ischemic pattern of LGE on cardiac MR o Subendocardial LGE in distribution of a coronary artery Acute Myocarditis  Subepicardial or midmyocardial pattern of LGE  Increase in T2 signal and increased early global relative enhancement can be seen in both stress cardiomyopathy and myocarditis Coronary Vasospasm  Prinzmetal angina  Due to focal coronary artery vasospasm  May be associated with acute myocardial infarction, serious ventricular arrhythmias, and sudden death P.7:64

PATHOLOGY General Features  Etiology o Precipitated by emotional or physical stress in most patients o Precise pathophysiology is not well established o Increased sympathetic activity has been suggested as central mechanism o Microvascular dysfunction o Cardiac MR shows evidence of myocardial edema and inflammation Microscopic Features  Endomyocardial biopsy shows disorganized contractile proteins, increased collagen-1, and no evidence of cell necrosis CLINICAL ISSUES Presentation  Most common signs/symptoms o Initial presentation can closely resemble that of acute myocardial infarction or acute coronary syndrome  Chest pain and dyspnea  Spectrum of ECG changes, including ST elevation, ST depression, T-wave inversion o Mild elevation of cardiac biomarkers (troponin I or T, CK-MB)  Degree of elevation of biomarkers often does not correlate with extent of ventricular dysfunction o Congestive heart failure  Elevated jugular venous pressure on exam  Pulmonary edema  Hypotension  Other signs/symptoms o Patients may have more serious presentations, such as cardiogenic shock or ventricular fibrillation Demographics  Age o Majority of cases are in postmenopausal females  Gender o M:F = 1:6  Epidemiology o May account for 2% of patients presenting with acute coronary syndrome Natural History & Prognosis  Mortality range in hospitals: 0-8% o Most patients recover LV function within 4 weeks o Recurrence occurs in ˜ 10% of patients  Most common complication is heart failure ± pulmonary edema 610

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May have increased risk of thrombus formation in akinetic apex Tachy- and bradyarrhythmias Transient LV outflow tract obstruction has been described

Treatment  Supportive care with standard heart failure medications (β-blockers, angiotensin-converting enzyme [ACE] inhibitor, diuretics) o Optimal duration of therapy is unclear  Intra-aortic balloon counterpulsation in cases of refractory shock  Anticoagulation in cases of apical thrombus formation DIAGNOSTIC CHECKLIST Consider  Echocardiogram &/or LV ventriculogram are often 1st imaging tests  Cardiac MR can help distinguish between other causes of cardiomyopathy and allows for additional myocardial tissue characterization Image Interpretation Pearls  On cardiac MR, both myocarditis and stress cardiomyopathy can present with myocardial edema and increased early global relative enhancement. SELECTED REFERENCES 1. Eitel I et al: Clinical characteristics and cardiovascular magnetic resonance findings in stress (takotsubo) cardiomyopathy. JAMA. 306(3):277-86, 2011 2. King A: Cardiomyopathies: CMR sheds new light on the clinical profile of stress cardiomyopathy. Nat Rev Cardiol. 8(9):480, 2011 3. Hurst RT et al: Takotsubo cardiomyopathy: a unique cardiomyopathy with variable ventricular morphology. JACC Cardiovasc Imaging. 3(6):641-9, 2010 4. Sharkey SW et al: Natural history and expansive clinical profile of stress (tako-tsubo) cardiomyopathy. J Am Coll Cardiol. 55(4):333-41, 2010 5. Celik T et al: Stress-induced (Takotsubo) cardiomyopathy: a transient disorder. Int J Cardiol. 131(2):265-6, 2009 6. Rolf A et al: Immunohistological basis of the late gadolinium enhancement phenomenon in tako-tsubo cardiomyopathy. Eur Heart J. 30(13):1635-42, 2009 7. Dorfman TA et al: An unusual manifestation of Takotsubo cardiomyopathy. Clin Cardiol. 31(5):194-200, 2008 8. Arora S: Autonomic imbalance in patients with takotsubo cardiomyopathy: cause or association? QJM. 100(9):5934; author reply 594-6, 2007 9. Cocco G et al: Stress-induced cardiomyopathy: a review. Eur J Intern Med. 18(5):369-79, 2007 10. Haghi D et al: Guidelines for diagnosis of takotsubo (ampulla) cardiomyopathy. Circ J. 71(10):1664; author reply 1665, 2007 11. Kawai S: Typical and atypical forms of takotsubo (ampulla) cardiomyopathy. Circ J. 71(10):1665, 2007 12. Kimura K et al: Images in cardiovascular medicine. Rapid formation of left ventricular giant thrombus with Takotsubo cardiomyopathy. Circulation. 115(23):e620-1, 2007 13. Matsuzaki M: Stress ‘Takotsubo’ cardiomyopathy: questions still remain. Nat Clin Pract Cardiovasc Med. 4(11):577, 2007 14. Nanda S et al: Takotsubo cardiomyopathy—a new variant and widening disease spectrum. Int J Cardiol. 120(2):e34-6, 2007 15. Pilgrim TM et al: Takotsubo cardiomyopathy or transient left ventricular apical ballooning syndrome: A systematic review. Int J Cardiol. 2007 16. Gianni M et al: Apical ballooning syndrome or takotsubo cardiomyopathy: a systematic review. Eur Heart J. 27(13):1523-9, 2006 17. Iqbal MB et al: Stress, emotion and the heart: tako-tsubo cardiomyopathy. Postgrad Med J. 82(974):e29, 2006 18. Bybee KA et al: Systematic review: transient left ventricular apical ballooning: a syndrome that mimics ST-segment elevation myocardial infarction. Ann Intern Med. 141(11):858-65, 2004 P.7:65

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(Left) Three-chamber view echocardiogram image shows hypokinesis of the mid to apical LV in an elderly woman presenting with chest pain and anterior ST elevations shortly after learning of the death of a loved one. (Right) Coronary angiography (same patient) shows absence of significant obstructive coronary artery disease of the left circumflex and left anterior descending coronary arteries. The right coronary artery (not shown) was also normal.

(Left) Left ventriculography image was obtained during diastole in the cardiac catheterization lab via a pigtail catheter . (Right) Left ventriculography image was obtained in the cardiac cath lab during systole. Note severe hypokinesis of the mid to apical segments of the LV with preserved contractility of the basal segments . This pattern of regional wall motion abnormality, coupled with the absence of obstructive coronary artery disease, is consistent with stress cardiomyopathy.

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(Left) Cardiac CT was performed in an elderly woman presenting with anterior ST elevations and increased troponin, who refused cardiac cath and was hemodynamically stable. Curved MPR image of the left anterior descending artery shows no evidence of coronary artery disease. (Right) Two-chamber image during systole (same patient) shows severe hypokinesis of the LV apex with preserved contractility of the basal to mid LV segments, consistent with stress cardiomyopathy.

Section 8 - Coronary Artery Disease Approach to Coronary Heart Disease Introduction Coronary artery disease is a leading cause of morbidity and mortality in Western countries. The underlying pathology is the development of atherosclerotic plaque in the intima of the coronary arteries. While in most cases coronary atherosclerotic plaque will remain clinically silent, it can clinically manifest in a number of forms, such as stable coronary artery disease, acute coronary syndrome, heart failure, and sudden cardiac death. Clinical Manifestations of Coronary Artery Disease Stable Coronary Artery Disease In stable coronary artery disease, atherosclerotic plaque deposits in the coronary arteries lead to significant narrowing of the coronary lumen with subsequent obstruction of the coronary blood stream. This results in deficit in oxygen supply of the downstream myocardium during situations of increased demand (typically physical exercise). There is no close correlation between the anatomic degree of luminal obstruction and the extent of downstream ischemia at exercise, which depends on numerous factors. These include the severity and length of the lesion, the amount of dependent myocardium, the resistance of the microvasculature, and the amount of collateral flow from other coronary territories. Revascularization serves to treat symptoms and improve prognosis and is usually recommended when the amount of ischemic myocardium exceeds 10% of the left ventricular mass. Acute Coronary Syndromes Acute coronary syndromes have a mechanism that is different from stable coronary artery disease. Typically, the index event is the rupture (most frequently) or erosion (less frequently) of the fibrous cap of an atherosclerotic plaque. Material from within the plaque is exposed to the blood stream and leads to immediate thrombocyte aggregation so that a thrombus forms on the surface of the ruptured plaque. This thrombus can obstruct coronary blood flow, and depending on the degree of obstruction and downstream myocardial damage, the resulting clinical manifestation is either completely silent or symptomatic in the form of unstable angina, non-ST-elevation myocardial infarction, or ST-elevation myocardial infarction. Treatment is usually emergent and includes both medication to counter thrombus aggregation and mechanical interventions to restore blood flow. Heart Failure Acute coronary syndromes, including myocardial infarction, can remain clinically silent; therefore, substantial damage to the myocardium can occur without the patient's noticing any chest pain episodes. It is possible that heart failure with severely impaired left ventricular function is the first clinical manifestation of coronary artery disease, and patients with newly identified heart failure need to be worked up for the presence of coronary artery obstruction.

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Diagnostic Imaging Cardiovascular Especially when left ventricular functional impairment is regional and not homogeneous, coronary artery disease should be strongly suspected. Sudden Cardiac Death Sudden death is a possible first manifestation of coronary artery disease. The underlying event is almost uniformly arrhythmia. (Acute mechanical complications, such as myocardial rupture secondary to an acute myocardial infarction, are possible but exceedingly infrequent). Arrhythmia leading to sudden death is usually ventricular fibrillation. It can either occur in the context of an acute coronary syndrome or be triggered by the sudden ischemia, or it can occur in patients with heart failure due to old, often previously unknown, myocardial infarction. Diagnostic Strategies Stable Coronary Artery Disease Two diagnostic strategies exist for the diagnosis of stable coronary artery disease. The underlying process is the presence of coronary stenoses that lead to myocardial ischemia. Testing can aim either at identifying the ischemic myocardium under exercise or at the direct visualization of coronary artery stenoses. Since not all coronary stenoses cause ischemia, and since stenoses that do not cause ischemia do not require revascularization, the usual preferred approach in patients with suspected stable coronary artery disease is the noninvasive identification of stress-induced myocardial ischemia. It can be achieved with physical exercise (treadmill or bicycle exercise) or pharmacologic stress (dipyridamole or dobutamine to increase contractility and myocardial oxygen demand or adenosine to achieve maximum vasodilation and “steal” effects). Commonly used tests include single-photon emission computed tomography (SPECT) and positron emission tomography (PET) myocardial perfusion and metabolic imaging, stress echocardiography, and stress magnetic resonance (MR) imaging. Another strategy is the direct visualization of coronary anatomy, as achieved by invasive coronary angiography or noninvasively by computed tomography (CT) coronary angiography. It is limited by the fact that not all stenoses cause ischemia and hence require revascularization, and if a stenosis is detected, it may be difficult to determine whether it mandates treatment. Invasive coronary angiography can be combined with measurement of the fractional flow reserve (FFR), which quantifies the relationship of mean arterial blood pressure before and after the stenosis during maximum vasodilation achieved by adenosine. Currently, FFR is considered the gold standard to identify myocardial ischemia, and FFR values < 0.8 indicate that the respective lesion should be revascularized. Both testing approaches, ischemia and coronary anatomy, have certain limitations. Ischemia testing has limited sensitivity and specificity. Also, ischemia testing cannot identify coronary atherosclerotic plaque, which is nonobstructive but might have implications for the future cardiovascular event risk. Anatomic imaging, on the other hand, often identifies stenoses, and the treating physician (and patient) may feel compelled to perform revascularization, even though not all stenoses cause relevant ischemia. Additionally, invasive coronary angiography is associated with potential complications, and noninvasive coronary angiography by CT suffers from limited image quality, which, if misinterpreted, can lead to false-positive findings and unnecessary downstream P.8:3 testing. Hence, the testing strategy has to take into account patient characteristics, pretest likelihood, and also local expertise with the various diagnostic tests. The most frequently applied strategy encompasses initial testing for ischemia, followed, if positive, by anatomic imaging. Coronary visualization by CT, however, may be a suitable alternative to reliably rule out coronary stenoses, especially in patients who do not have a high likelihood of being diseased. Acute Coronary Syndromes Acute coronary syndromes encompass a wide spectrum from unstable angina to ST-segment elevation myocardial infarction (STEMI). In STEMI, electrocardiography is the only test performed and leads to immediate coronary catheterization. In non-ST elevation acute coronary syndromes, further testing is usually performed before a decision about invasive angiography can be made. It includes laboratory testing (troponin) complemented by echocardiography to exclude differential diagnoses (acute pulmonary embolism, aortic dissection) and assess regional as well as global left ventricular function. It may also include testing for ischemia. Coronary CT angiography plays an increasingly important role to rule out coronary artery disease, especially in patients who present with acute chest pain but have a relatively low pretest likelihood of acute coronary disease. Prevention Prevention of the first acute coronary event is an important goal in coronary artery disease. In individuals who are asymptomatic, the traditional risk factors, summarized, for example, in the Framingham Risk Score, are used to estimate the risk and the necessity of risk-lowering treatment by statins, aspirin, or antihypertensive medication. It is increasingly recognized that imaging may also contribute to risk stratification (e.g., coronary calcium), but the role of imaging in primary prevention has not been definitely clarified. It remains uncertain which individuals will benefit from imaging in the context of primary prevention. Summary

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Diagnostic Imaging Cardiovascular Numerous diagnostic strategies are available to address the various clinical manifestations of coronary artery disease. No single test is perfectly suited for all patients; the decision about the best testing strategy must take into account patient characteristics, such as the ability to breath-hold, obesity, arrhythmias, and metallic implants. One must also consider the pretest likelihood of disease and local expertise with the various diagnostic tools. Selected References 1. Achenbach S et al: CV imaging: what was new in 2012? JACC Cardiovasc Imaging. 6(6):714-34, 2013 2. Coelho-Filho OR et al: MR myocardial perfusion imaging. Radiology. 266(3):701-15, 2013 3. Dowsley T et al: The role of noninvasive imaging in coronary artery disease detection, prognosis, and clinical decision making. Can J Cardiol. 29(3):285-96, 2013 4. Nakazato R et al: Myocardial perfusion imaging with PET. Imaging Med. 5(1):35-46, 2013 5. Bamberg F et al: Imaging evaluation of acute chest pain: systematic review of evidence base and cost-effectiveness. J Thorac Imaging. 27(5):289-95, 2012 6. de Jong MC et al: Diagnostic performance of stress myocardial perfusion imaging for coronary artery disease: a systematic review and meta-analysis. Eur Radiol. 22(9):1881-95, 2012 7. Fihn SD et al: 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American College of Physicians, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol. 60(24):e44-e164, 2012 8. Joshi FR et al: Non-invasive imaging of atherosclerosis. Eur Heart J Cardiovasc Imaging. 13(3):205-18, 2012 9. Mc Ardle B et al: Nuclear perfusion imaging for functional evaluation of patients with known or suspected coronary artery disease: the future is now. Future Cardiol. 8(4):603-22, 2012 10. Parker MW et al: Diagnostic accuracy of cardiac positron emission tomography versus single photon emission computed tomography for coronary artery disease: a bivariate meta-analysis. Circ Cardiovasc Imaging. 5(6):700-7, 2012 11. Qaseem A et al: Diagnosis of stable ischemic heart disease: summary of a clinical practice guideline from the American College of Physicians/American College of Cardiology Foundation/American Heart Association/American Association for Thoracic Surgery/Preventive Cardiovascular Nurses Association/Society of Thoracic Surgeons. Ann Intern Med. 157(10):729-34, 2012 12. American College of Cardiology Foundation Appropriate Use Criteria Task Force et al: ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 Appropriate Use Criteria for Echocardiography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, American Society of Echocardiography, American Heart Association, American Society of Nuclear Cardiology, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Critical Care Medicine, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance American College of Chest Physicians. J Am Soc Echocardiogr. 24(3):229-67, 2011 13. Corti R et al: Imaging of atherosclerosis: magnetic resonance imaging. Eur Heart J. 32(14):1709-19b, 2011 14. Achenbach S et al: Imaging of coronary atherosclerosis by computed tomography. Eur Heart J. 31(12):1442-8, 2010 15. Achenbach S et al: The year in coronary artery disease. JACC Cardiovasc Imaging. 3(10):1065-77, 2010 16. Taylor AJ et al: ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. Circulation. 122(21):e525-55, 2010 17. Abdelmoneim SS et al: Quantitative myocardial contrast echocardiography during pharmacological stress for diagnosis of coronary artery disease: a systematic review and meta-analysis of diagnostic accuracy studies. Eur J Echocardiogr. 10(7):813-25, 2009 18. Schuijf JD et al: How to identify the asymptomatic high-risk patient? Curr Probl Cardiol. 34(11):539-77, 2009

Coronary Anatomy TERMINOLOGY Abbreviations  Coronary arteries and their branches o Left main (LM) coronary artery o Left anterior descending (LAD) coronary artery  Proximal, mid, and distal LAD (pLAD, mLAD, dLAD)  Diagonal branches: D1, D2, D3, etc. o Ramus intermedius (RI) 615

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o o o o

Left circumflex (LCX)  Proximal and mid/distal LCX (pCx, LCX)  Obtuse marginal branches: OM1, OM2, OM3, etc. Posterior lateral branch (PLB) Posterior left ventricular (PLV) branch Posterior descending artery (PDA) Right coronary artery (RCA)  Proximal, mid, and distal RCA (pRCA, mRCA, dRCA)  Acute marginal (AM) branch Sinoatrial node (SAN) branch Atrioventricular node (AVN) branch

o o  Grafts o Saphenous vein graft (SVG) o Coronary artery bypass graft (CABG) o Left internal mammary artery (LIMA) o Right internal mammary artery (RIMA)  Alternative international nomenclature o Ramus interventricularis anterior (RIVA) = LAD o Ramus circumflexus (RCx) = LCX o Ramus interventricularis posterior (RIVP, RIP) = PDA o Ramus marginalis (RM or M) = OM o Right posterolateral branch (RPL) = PLV branch from RCA  Ramus posterolateralis dexter (RPD) = PLV branch from RCA; careful not to confuse with abbreviation for right posterior descending artery o Right posterior descending artery (RPD) = PDA from RCA Synonyms  Epicardial arteries IMAGING ANATOMY Overview  Major coronary arteries travel within epicardial fat of interventricular and atrioventricular grooves  Considerable variability in size, number/location of branching vessels, and myocardial territories ANATOMY LM  Arises from left coronary sinus  Variable length but usually < 2 cm  Courses behind right ventricular outflow tract, between pulmonary trunk and left atrium  LM stenosis ≥ 50% is significant o In contrast, stenosis of ≥70% is significant in all other segments  Usually bifurcates into LAD and LCX  Commonly trifurcates into LAD, LCX, and RI o RI may follow the course of obtuse marginal or diagonal branch  Rarely is absent with LM and LCX origins directly from left coronary sinus LAD  Continuation of LM  Runs along anterior interventricular groove  Occasionally dives into left ventricular myocardium, forming “myocardial bridge”  Diagonal branches run diagonally over anterior left ventricular wall o Numbered sequentially from proximal to distal (D1, D2, D3) o Supply anterolateral wall  Superior septal perforator branches extend into interventricular septum and anchor LAD to myocardium o Septal perforators supply anterior 2/3 of septum o 1st septal perforator commonly supplies His bundle and branches of AVN o May form collaterals to PDA via inferior septal perforators  Right ventricular branches are small but may form collaterals to RCA o Circle of Vieussens = collateralization between branch of proximal LAD (left preinfundibular artery) and conus artery in setting of proximal LAD stenosis  Distal LAD often wraps around apex and may form collaterals to distal PDA  Segmentation 616

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Proximal LAD: End of LM to 1st large septal or D1 (1st diagonal), whichever is more proximal Mid LAD: End of proximal LAD to 1/2 the distance to the apex  Some authors use origin of D2 (2nd diagonal) as distal landmark Distal LAD: End of mid LAD to end of LAD

LCX        

Arises from LM at nearly perpendicular angle Runs around mitral annulus in left atrioventricular groove Obtuse marginal branches (OM1, OM2, OM3) Nondominant LCX often terminates as OM branch Native LCX distal to OM branches is often diminutive If left dominant, branches into PLV and PDA LCX and OM branches supply lateral free wall and portion of anterolateral papillary muscle Segmentation o Proximal LCX: End of LM to origin of OM1 (1st obtuse marginal branch) o Mid and distal LCX: Distal to OM1 to end of LCX or PDA origin

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Arises from right coronary sinus Passes under right atrial appendage and descends into right anterior atrioventricular groove In 50%, 1st branch of RCA is conus branch o Alternative origin from a separate ostium directly from right sinus of Valsalva o Conus branch supplies right ventricular outflow tract In 60%, SAN is the next branch o 40% take alternative supply from LCX atrial branches Acute marginal branches may be large and extend to apex P.8:5

RCA

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If right-dominant circulation, RCA bifurcates into PDA and PLV at cardiac crux o When right dominant, described as right PDA (R-PDA); when left dominant, left PDA (L-PDA) o PDA runs along posterior interventricular groove and supplies posterior 1/3 of inferior septum o PLV courses cephalad and is usual source of AVN branch  Segmentation o Proximal RCA: Ostium to 1/2 the distance to acute margin of heart o Mid RCA: End of proximal RCA to acute margin o Distal RCA: Acute margin to PDA origin Dominance  Dominance is defined by supply of PDA and PLV  There are right-, left-, and codominant coronary systems  ˜ 85% are right dominant (RCA supplies PDA and PLV)  8% are left dominant (LCX supplies PDA and PLV)  7% are codominant (RCA and LCX share supply of PDA &/or PLV)  Rare super-dominant RCA supplies territory of diminutive LCX  Rare wrap-around LAD supplies PDA CORONARY ARTERY SEGMENTATION Society of Cardiovascular Computed Tomography Definitions  Left main (LM) = ostium of LM to bifurcation to LAD/LCX or trifurcation to LAD/LCX/RI  Proximal LAD (pLAD) = end of LM to 1st large septal or diagonal, whichever is more proximal  Mid LAD (mLAD) = end of pLAD to 1/2 the distance to apex  Distal LAD (dLAD) = end of mLAD to end of LAD  Diagonal 1 (D1) = 1st diagonal branch of LAD  Diagonal 2 (D2) = 2nd diagonal branch of LAD  Ramus intermedius (RI) = vessel arising from LM between LAD and LCX in the case of trifurcation  Proximal left circumflex (pCx) = end of LM to origin of 1st obtuse marginal  Mid and distal left circumflex (LCX) = from 1st obtuse marginal to end of vessel or origin of L-PDA  Obtuse marginal 1 (OM1) = 1st obtuse marginal branch of left circumflex  PDA-LCX (L-PDA) = PDA from LCX  PLB-L (L-PLB) = posterolateral branch from LCX  Proximal RCA (pRCA) = ostium of RCA to 1/2 the distance to acute margin 617

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Mid RCA (mRCA) = end of pRCA to acute margin Distal RCA (dRCA) = acute margin to origin of PDA PDA-RCA (R-PDA) = PDA from RCA PLB-RCA (R-PLB) = posterolateral branch from RCA Alternative coronary artery segmentation o Original 15-segment model published via American Heart Association committee by W. Gerald Austen in 1975 o 28-segment model of Myocardial Infarction and Mortality in Coronary Artery Surgery Study  Of note, some authors use 2nd diagonal branch (rather than 1/2 the distance from 1st branch) to apex as landmark dividing mid and distal LAD NORMAL VARIANTS AND ANOMALIES General Considerations  Wide degree of variation with variable clinical significance  Categorized as anomalies of origin, course, intrinsic anatomy, and termination Anomalies of Origin and Course  Absence of LM, with separate ostia of LAD and LCX directly from left coronary sinus  High (above sinotubular junction) origin of coronary ostium  Origin from opposite or rarely noncoronary cusp with anomalous course o Benign variants have course either retroaortic or prepulmonic/anterior to right ventricular outflow tract o Malignant variants have interarterial course between aorta and pulmonary artery o Transseptal variant of malignant type, where vessel runs in myocardium just below interarterial space, is considered less malignant compared to other anomalies  Anomalous left coronary artery from pulmonary artery (ALCAPA)  Single coronary artery Anomalies of Intrinsic Anatomy  Congenital coronary ostial stenosis or atresia  Congenital or acquired coronary ectasis or aneurysm  Myocardial bridge  Duplicated coronary artery Anomalies of Termination  Coronary-venous or coronary-cameral fistula  Extracardiac termination CARDIAC VEINS  Anterior cardiac veins drain anterior right ventricular free wall, cross right atrioventricular groove, and enter right atrium directly  Coronary sinus, the largest cardiac vein at ˜ 14 mm diameter, enters right atrium near inferior vena cava inflow o There may be a complete or incomplete valve at its ostium (Thebesian valve)  Middle cardiac vein runs in posterior interventricular groove and enters coronary sinus near its ostium  Other tributaries to coronary sinus are posterior vein of left ventricle (drains inferior left ventricular wall), marginal veins, and great cardiac vein, which runs in left atrioventricular groove  Anteriorly, great cardiac vein becomes anterior interventricular vein, which runs parallel to LAD and receives diagonal veins RELATED REFERENCES 1. Raff GL et al: SCCT guidelines for the interpretation and reporting of coronary computed tomographic angiography. J Cardiovasc Comput Tomogr. 3(2):122-36, 2009 2. Abbara S et al: Noninvasive evaluation of cardiac veins with 16-MDCT angiography. AJR Am J Roentgenol. 185(4):1001-6, 2005 P.8:6

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(Top) Volume-rendered image shows the aortic root and coronary arteries, oriented to depict the right coronary artery. (Bottom) Volume-rendered image shows the aortic root and coronary arteries, oriented to depict the left coronary arteries. P.8:7

CORONARY ARTERY ORIGINS

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(Top) 3D volume-rendered anteroposterior image shows the coronary artery origins. The right ventricular outflow tract and atrial appendages have been excluded to depict the coronary origins. (Middle) 3D volume-rendered anteroposterior image shows the coronary artery origins. The right ventricular outflow tract and atrial appendages have been excluded to depict the coronary origins. (Bottom) 3D volume-rendered images show the diaphragmatic surface of the heart. In this right-dominant coronary arterial system, the RCA continues as the PDA along the posterior interventricular groove. P.8:8

LEFT CORONARY ARTERIES

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(Top) Right anterior oblique caudal view of selective angiography shows a left-dominant coronary system. (Bottom) 3D volume-rendered image shows the left coronary arteries. P.8:9

RIGHT CORONARY ARTERIES

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(Top) Left anterior oblique projection shows a right-dominant coronary system. (Middle) This is a curved maximumintensity projection (MIP) along the course of a dominant RCA. The view is known as the C view due to the characteristic appearance of the RCA. (Bottom) Curved MIP depicts the sinoatrial artery arising from the proximal RCA, the most common variant. Less commonly, the sinoatrial artery arises from the LCX. Rarely, it may arise directly from the right coronary sinus. P.8:10

LEFT CORONARY ARTERIES

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(Top) Image demonstrates the course and origin of the left circumflex coronary artery. Left anterior oblique caudal “spider” view depicts the left main, proximal LAD, and left circumflex coronary arteries. (Middle) 3D volume-rendered image shows the left main coronary artery bifurcation. The left atrial appendage has been excluded as the left main coronary artery would otherwise be hidden underneath. (Bottom) 3D volume-rendered image shows the left main trifurcation into left anterior descending, ramus intermedius, and circumflex coronary arteries. P.8:11

LEFT CORONARY ARTERIES

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(Top) Axial maximum-intensity projection image demonstrates trifurcation of the left main coronary artery into left anterior descending, ramus intermedius, and left circumflex branches. Here, the sinoatrial nodal artery arises from the proximal LCX, a normal variant. (Middle) 3D volume rendering shows a left main coronary artery trifurcation. The ramus intermedius most commonly courses laterally in a similar direction as the 1st diagonal but can also run parallel to the obtuse marginal arteries. (Bottom) 3D volume rendering shows an uncommon normal variant where the left main coronary artery is absent and the left anterior descending and circumflex arteries arise from separate ostia off the left coronary sinus. P.8:12

LEFT-, RIGHT-, AND CODOMINANT SYSTEMS

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(Top) 3D volume-rendered image shows the inferior surface of the heart in a right-dominant system. Note the middle cardiac vein, which courses alongside the PDA in the posterior interventricular groove. (Middle) Codominant coronary system is shown. The PLV is supplied from the circumflex, and the PDA arises from the RCA. (Bottom) Left-dominant coronary system is shown. Both the PDA and the PLV arise from the LCX. P.8:13

CORONARY ARTERIES ORIGINS AND COURSE

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(Top) Curved multiplanar reformation (MPR) shows the left anterior descending coronary artery, which arises from the left main coronary artery and travels along the anterior interventricular groove. (Middle) Curved MPR shows the left circumflex coronary artery, which arises from the left main coronary artery and descends into the left atrioventricular groove. (Bottom) Curved MPR shows the right coronary artery, which arises from the right coronary sinus and passes under the right atrial appendage as it descends into right atrioventricular groove. P.8:14

PERFUSION TERRITORIES

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(Top) Graphic depicts the 17 left ventricular myocardial segments with corresponding color-coded coronary artery perfusion territories for a right-dominant coronary system. (Bottom) Typically, the LAD supplies the anterior wall, anteroseptal wall, and apex. The LCX supplies the lateral wall. The RCA supplies the inferior and inferoseptal walls. Considerable normal variation exists, and these perfusion territories should be considered as a guideline rather than a rule. P.8:15

18-SEGMENT CORONARY MODEL

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(Top) Society of Cardiovascular Computed Tomography (SCCT) 18-segment coronary model, a modification of the original 1975 American Heart Association 15-segment model, is outlined. (Bottom) Awareness of the differences between these 2 models is important to avoid confusion. First, ramus intermedius and left posterolateral branches have been included as the 17th and 18th segments. Second, the mid and distal LCX are considered a single segment. Third, the boundary between the mid and distal LAD is defined as 1/2 the distance to the cardiac apex rather than the origin of the 2nd diagonal branch. (Adapted from Raff GL et al: SCCT guidelines for the interpretation and reporting of coronary computed tomographic angiography. J Cardiovasc Comput Tomogr. 3[2]:122-36, 2009.)

Anomalous Left Coronary Artery, Malignant Key Facts Terminology  Origin of left main or left anterior descending coronary artery from right sinus of Valsalva with course between ascending aorta and pulmonary artery o Associated with increased risk for myocardial ischemia or sudden cardiac death Imaging  May be detected by very experienced operator in transesophageal echocardiography  Can be suspected in invasive coronary angiography, but exact course is difficult to ascertain even in multiple projections  Coronary CTA is gold standard for identification of anomalous coronary arteries and definition of their exact course, including their relationship to surrounding structures 628

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In experienced hands, contrast-enhanced MRA has high accuracy for identification of anomalous coronary arteries and their proximal course Top Differential Diagnoses  Aortic dissection  Benign anomalous coronary artery  Many other coronary anomalies that are not associated with increased risk for sudden death Clinical Issues  Most common signs/symptoms: Sudden cardiac death, chest pain o Less frequent: Syncope, arrhythmia, and palpitations  Sudden death rarely occurs over age of 35 and is often related to exercise  Therapeutic options include stent placement and surgery

(Left) Graphic compares normal (top) and potentially malignant (bottom) courses of a left main (LM) coronary artery. If LM arises from the right sinus of Valsalva (or proximal right coronary artery), its course is considered potentially malignant and is associated with higher incidence of sudden cardiac death if LM follows an interarterial path between the aortic root and right ventricular outflow tract or pulmonary artery. (Right) Axial coronary CTA shows an interarterial (potentially malignant) LM course .

(Left) Multiplanar reconstruction in coronal orientation (same patient) shows LM in cross section , positioned between the aorta and right ventricular outflow tract . It is assumed that squeezing and stretching of LM can lead to ischemia and sudden death. (Right) Invasive coronary angiography (right anterior oblique view) of the same patient does not allow assessment of the exact path of the anomalous LM . P.8:17

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Diagnostic Imaging Cardiovascular TERMINOLOGY Definitions  Origin of left main (LM) or left anterior descending (LAD) coronary artery from right sinus of Valsalva with course between ascending aorta and pulmonary artery (PA)  Associated with increased risk for myocardial ischemia or sudden cardiac death (SCD)  Other potentially malignant anomalies include o Origin of left coronary artery (LCA) from PA  Extremely infrequent  Usually detected in childhood o Right coronary artery (RCA) arising from left sinus of Valsalva with course between ascending aorta and PA  Substantially more frequent  There is debate concerning its relevance IMAGING General Features  Best diagnostic clue o LCA arising from right sinus of Valsalva or very proximal RCA and passing between ascending aorta and PA  Best detected in cross-sectional imaging o Ischemia in noninvasive testing can be an indication Echocardiographic Findings  Transesophageal echocardiography can identify ostia of coronary arteries, and a very experienced operator can characterize their proximal course in many cases CT Findings  ECG-gated contrast-enhanced coronary CT angiography (CTA) o Gold standard for identification of anomalous coronary arteries and definition of their exact course, including their relationship to surrounding structures MR Findings  Contrast-enhanced coronary MR angiography (MRA) o Highly accurate in identifying anomalous coronary arteries and their proximal course in experienced hands o More difficult to perform and lower spatial resolution than coronary CT angiography Angiographic Findings  Invasive coronary angiography o Even with multiple projections and insertion of PA catheter to delineate PA, it may not be possible to identify the exact course of anomalous LCA DIFFERENTIAL DIAGNOSIS Aortic Dissection  In low-quality nongated CTA of aorta, anomalous LCA could mimic the appearance of dissection in aortic root (and vice versa) Coronary Artery Stenosis  Both coronary artery stenosis and anomalous coronary artery can cause ischemia and chest pain Benign Anomalous Coronary Artery  LM or LAD arising from right side with transseptal or subpulmonary course (through ventricular septum beneath right ventricular infundibulum)  LM or LAD arising from right side; course anterior to PA  LM or LAD with retroaortic course  Any anomaly of left circumflex coronary artery Anomalous Right Coronary Artery  RCA arising from left sinus of Valsalva is a relatively frequent coronary anomaly  Prevalence in patients who die suddenly is lower than that of malignant LCA anomaly  Question whether or not to classify RCA arising from left sinus of Valsalva and passing between aorta and PA as malignant anomaly is debated among experts  Testing for ischemia (preferably with physical exercise) is a reasonable approach PATHOLOGY General Features  Exact mechanism of sudden death is not known o Most likely, ischemia and subsequent arrhythmias 630

Diagnostic Imaging Cardiovascular o Sudden death is related to exercise in > 50% of cases Gross Pathologic & Surgical Features  Several anatomic features have been identified as particularly high risk when LM or LAD follows a course between aorta and PA: Slit-like aortic ostium, acute angle takeoff, and intramural aortic segment CLINICAL ISSUES Presentation  Most common signs/symptoms o SCD, chest pain  Other signs/symptoms o Syncope, arrhythmia, and palpitations Demographics  Age o Sudden death rarely occurs in patients over 35  Epidemiology o Malignant interarterial course of LCA is found in ˜ 1.3% of all coronary anomalies o Most individuals with this anomaly never experience any clinical manifestation Treatment  Coronary bypass surgery, surgical unroofing, or reimplantation of coronaries above appropriate coronary sinus  Excellent prognosis with early treatment  Treatment is indicated in patients who have demonstrable ischemia or who have survived SCD  Benefit is controversial in patients who are completely asymptomatic and have normal stress test results SELECTED REFERENCES 1. Peñalver JM et al: Anomalous aortic origin of coronary arteries from the opposite sinus: a critical appraisal of risk. BMC Cardiovasc Disord. 12:83, 2012

Anomalous Left Coronary Artery, Benign Key Facts Terminology  Origin of left main coronary artery or left anterior descending coronary artery from right coronary cusp and a course o Anterior to pulmonary artery (prepulmonary course) o Behind aortic root (retroaortic course) Imaging  Anomalous origin of left coronary artery can be detected in invasive coronary angiography, but exact course can be difficult to ascertain o Retroaortic course of anomalous coronary artery originating from right coronary cusp is usually straightforward to identify o Origin of septal perforator branches from anomalous left main coronary artery makes subpulmonary (transseptal) course likely o Prepulmonary and transseptal courses are difficult to differentiate from interarterial course, the latter of which is assumed to be high risk (malignant)  May be detected by a very experienced operator in transesophageal echocardiography Top Differential Diagnoses  Occlusion of left main or left anterior descending coronary artery  High-risk (malignant) anomalous left coronary artery Clinical Issues  Anomalous left coronary artery arising from right coronary cusp is present in ˜ 0.02-0.1% of population  Usually an incidental finding  Coronary artery disease may affect anomalous coronary arteries  No treatment is required

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(Left) Graphic shows normal left main (LM) coronary artery anatomy, potentially malignant interarterial course, and 3 benign variations of anomalous LM anatomy: Retroaortic course, anterior (a.k.a. prepulmonary) course, and transseptal (a.k.a. subpulmonary) course. (Right) CECT shows the retroaortic path of an anomalous LM that originates from the very proximal right coronary artery and courses dorsal to the aortic root toward the left . This course is benign and not associated with increased mortality.

(Left) CECT in a patient who presents with acute chest pain shows anomalous LM with right-sided origin that passes anterior to the pulmonary artery . This course is benign and carries no clinical relevance. Note pulmonary embolism . (Right) CECT shows anomalous LM that originates from right sinus of Valsalva and courses through the septum, below the pulmonary artery, to the left . This variant is similar to the potentially malignant interarterial course but not associated with increased mortality. P.8:19

TERMINOLOGY Definitions  Origin of left main coronary artery or left anterior descending coronary artery from right coronary cusp and a course o Anterior to pulmonary artery (prepulmonary course) o Behind aortic root (retroaortic course) o Through interventricular septum and below right ventricular outflow tract (subpulmonary or transseptal course) IMAGING General Features  Best diagnostic clue 632

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Left coronary artery arising from right sinus of Valsalva or very proximal right coronary artery and following prepulmonary, retroaortic, or transseptal course Echocardiographic Findings  Transesophageal echocardiography CT Findings  ECG-gated contrast-enhanced coronary CT angiography (CTA) o Gold standard for identification of anomalous coronary arteries and definition of their exact course, including their relationship to surrounding structures MR Findings  Contrast-enhanced coronary MR angiography (MRA) o High accuracy for identification of anomalous coronary arteries and their proximal course in experienced hands o More difficult to perform and lower spatial resolution than coronary CT angiography Angiographic Findings  Invasive coronary angiography o Retroaortic course of anomalous coronary artery originating from right coronary cusp is usually straightforward to identify o Origin of septal perforator branches from anomalous left main coronary artery makes subpulmonary (transseptal) course likely o Prepulmonary and transseptal courses are difficult to differentiate from interarterial course, the latter of which is assumed to be high risk (malignant) DIFFERENTIAL DIAGNOSIS Occlusion of Left Main or Left Anterior Descending Coronary Artery  Collaterals from right coronary artery (conus branch) may follow course very similar to prepulmonary course of right-sided anomalous left coronary artery High-Risk (Malignant) Anomalous Left Coronary Artery  Left main coronary artery or left anterior descending coronary artery arising from right side with course between ascending aorta and pulmonary artery  Risk of ischemia and sudden death is assumed to be associated with shear and squeezing of anomalous vessel and particularly pronounced when there is o Slit-like aortic ostium o Acute angle takeoff o Intramural segment of the anomalous artery (within aortic wall) Aortic Dissection  In low-quality CTA of aorta, anomalous left coronary artery arising from right coronary cusp could mimic appearance of dissection in aortic root PATHOLOGY General Features  Not linked to sudden cardiac death or ischemia CLINICAL ISSUES Presentation  Usually an incidental finding  Some authors speculate on potential of spasm in anomalous coronary artery  Coronary artery disease may affect anomalous coronary arteries Demographics  Age o Can incidentally be detected at any age  Epidemiology o Coronary anomalies are present in ˜ 0.3-1.6% of population o Anomalous left coronary artery arising from right coronary cusp is present in ˜ 0.02-0.1% of population Treatment  No treatment is required SELECTED REFERENCES 1. Peñalver JM et al: Anomalous aortic origin of coronary arteries from the opposite sinus: a critical appraisal of risk. BMC Cardiovasc Disord. 12:83, 2012 2. Cheitlin MD et al: Congenital anomalies of coronary arteries: role in the pathogenesis of sudden cardiac death. Herz. 34(4):268-79, 2009 633

Diagnostic Imaging Cardiovascular 3. Frommelt PC: Congenital coronary artery abnormalities predisposing to sudden cardiac death. Pacing Clin Electrophysiol. 32 Suppl 2:S63-6, 2009 4. Moustafa SE et al: Anomalous interarterial left coronary artery: an evidence based systematic overview. Int J Cardiol. 126(1):13-20, 2008 5. Angelini P: Coronary artery anomalies: an entity in search of an identity. Circulation. 115(10):1296-305, 2007 6. Jaggers J et al: Surgical therapy for anomalous aortic origin of the coronary arteries. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 122-7, 2005 7. Basso C et al: Clinical profile of congenital coronary artery anomalies with origin from the wrong aortic sinus leading to sudden death in young competitive athletes. J Am Coll Cardiol. 35(6):1493-501, 2000 8. McConnell MV et al: Identification of anomalous coronary arteries and their anatomic course by magnetic resonance coronary angiography. Circulation. 92(11):3158-62, 1995 P.8:20

Image Gallery

(Left) Coronary CTA shows an anomalous LM with right-sided origin and a retroaortic course. LM originates from the right sinus of Valsalva or right coronary artery (not seen here) and follows a course dorsal to the aortic root toward the left side . (Right) 3D reconstruction of the same anomaly shows the retroaortic course of the LM. The vessel then divides into a left circumflex and a left anterior descending coronary arteries, both of which follow a normal course.

(Left) Coronary CTA shows an anomalous LM that originates from the right sinus of Valsalva or right coronary artery (not seen here) and then follows a course anterior to the pulmonary artery and toward the left side . (Right) 3D reconstruction of the same anomaly shows the prepulmonary course of the LM. The vessel then divides into a left anterior descending coronary artery and a circumflex coronary artery and also gives off diagonal and obtuse marginal 634

Diagnostic Imaging Cardiovascular branches.

(Left) Coronary CTA shows an anomalous LM that originates from the right sinus of Valsalva and follows a course caudal to the pulmonary artery, through the interventricular septum and toward the left side . (Right) 3D reconstruction of the same anomaly shows the LM surfacing from below the pulmonary artery . The LM then divides into a left anterior descending and a left circumflex coronary arteries and also gives off an intermediate branch. P.8:21

(Left) Coronary CT angiogram shows another example of a prepulmonary (or anterior) course of the LM coronary artery. (Right) The corresponding 3D reconstruction clearly shows the course of the anomalous LM , which is anterior to the pulmonary artery, and absence of an artery originating from the left sinus of Valsalva. This is a benign coronary artery variant.

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(Left) Invasive coronary angiography of an anomalous LM shows that the LM originates from the same ostium as the right coronary artery and follows a subpulmonary (or transseptal) course. This can be identified because the LM gives rise to a small septal branch . (Right) An 8 mm thick maximum-intensity projection coronary CT angiogram of the same patient clearly shows the subpulmonary course of the LM and also the small septal branch .

(Left) Coronary CT angiography multiplanar reconstruction in coronal orientation in the same patient shows a cross section of the LM , which is embedded in the interventricular septum and gives rise to a small septal branch . (Right) CECT shows another example of an anomalous LM with transseptal course . The patient is 95 years old, and this fact indicates the benign nature of the anomaly.

Anomalous LCX Key Facts Terminology  Left circumflex (LCX) coronary artery originates from right sinus of Valsalva and courses posterior and inferior to the noncoronary cusp toward left side  No left main (LM) coronary artery segment is present Imaging  Abnormal vessel between noncoronary cusp and roof of atria  Abnormal vessel arising from right sinus of Valsalva or right coronary artery (RCA) that courses posteriorly  Originates from RCA, from common ostium with RCA, or directly from right sinus of Valsalva  Cardiac gated multidetector CT is best imaging tool 636

Diagnostic Imaging Cardiovascular  

Cardiac MR in young patients and other patients in whom radiation is to be avoided or minimized Dot sign on invasive angiogram with aortic root injection in right anterior oblique view o Dot represents contrast-filled LCX on end as it travels posterolaterally around aortic root  Selective angiography of left LAD from left sinus shows absence of vessel in left atrioventricular groove Top Differential Diagnoses  Anomalous RCA, benign variant  Coronary fistula  Sinoatrial node branch Clinical Issues  Anomalous LCX is most common variant of true coronary anomalies  Usually benign incidental finding Diagnostic Checklist  Space between aortic noncoronary sinus and atria does not normally contain any vessels

(Left) Curved MPR CTA images show anomalous left circumflex (LCX) and left anterior descending (LAD) arteries with separate origins from right coronary cusp. Right coronary artery (RCA) has normal origin. LCX takes retroaortic course between the aorta and left atrium. (Right) VR and oblique MPR images from CTA show anomalous LCX arising from right coronary cusp and having retroaortic course. RCA arises from right coronary cusp. LAD arises from left sinus of Valsalva. Left main coronary artery is absent.

(Left) Oblique graphic shows anomalous LCX arising from right sinus of Valsalva and coursing behind noncoronary sinus of Valsalva. RCA is normal. LAD arises directly from left sinus of Valsalva. (Right) Right anterior oblique view of coronary catheter angiogram with selective catheterization shows an anomalous LCX with a separate origin from the right coronary cusp and with a retroaortic course . P.8:23 637

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TERMINOLOGY Abbreviations  Anomalous left circumflex (LCX) coronary artery Definitions  LCX originates from right sinus of Valsalva and courses posterior and inferior to the noncoronary cusp toward left side o Left anterior descending (LAD) coronary artery originates directly from left sinus of Valsalva o No left main (LM) coronary artery segment is present IMAGING General Features  Best diagnostic clue o Abnormal vessel between noncoronary cusp and roof of atria o No LCX branch off LM/LAD o Abnormal vessel arising from right sinus of Valsalva or right coronary artery (RCA) that courses posteriorly o Rarely, anomalous origin of LCX can be from pulmonary artery  Mostly seen in childhood  Associated with other major congenital cardiac defects, such as patent ductus arteriosus, aortic coarctation, and subaortic stenosis  Location o Originates from RCA, from common ostium with RCA, or directly from right sinus of Valsalva  Size o Anomalous LCX is usually smaller, nondominant vessel Imaging Recommendations  Best imaging tool o Cardiac gated multidetector CT is best imaging tool o Cardiac MR in young patients and other patients in whom radiation is to be avoided or minimized  Protocol advice o Cardiac gating is necessary to eliminate aortic pulsation artifact CT Findings  Cardiac gated CTA o Considered gold standard as it demonstrates anomalous vessels at high spatial and contrast resolution and depicts relationship with surrounding structures o Anomalies with course outside the space between aorta and pulmonary artery are considered benign Angiographic Findings  Dot sign on invasive angiogram with aortic root injection in right anterior oblique view o Dot represents contrast-filled LCX on end as it travels posterolateral around aortic root  Selective angiography of left LAD from left sinus shows absence of vessel in left atrioventricular groove DIFFERENTIAL DIAGNOSIS Anomalous RCA, Benign Variant  Also runs posterior and inferior to noncoronary aortic sinus but in opposite direction Coronary Fistula  Usually multiple tortuous and enlarged feeders Sinoatrial Node Branch  Prominent sinoatrial nodal branch can be confused with anomalous LCX  Best clue is identification of normal LCX branch off LM CLINICAL ISSUES Presentation  Most common signs/symptoms o Asymptomatic Demographics  Age o Any  Gender o No sex predilection 638

Diagnostic Imaging Cardiovascular 

Epidemiology o Primary congenital anomalies of coronary arteries can be found in 1-2% of general population  Anomalous LCX is most common variant of true coronary anomalies Natural History & Prognosis  Usually benign incidental finding Treatment  No treatment is necessary  If anomalous origin from pulmonary artery, treatment is surgical with ligation of LCX at origin alone, ligation with aortocoronary bypass, or reimplantation of LCX to aorta DIAGNOSTIC CHECKLIST Consider  Volume-rendered CTA images are not useful unless atria are removed during segmentation Image Interpretation Pearls  Space between aortic noncoronary sinus and atria does not normally contain any vessels o If a vessel in this space is detected, it is pathognomonic for anomalous coronary artery and represents either anomalous LCX or anomalous RCA SELECTED REFERENCES 1. Dodd JD et al: Congenital anomalies of coronary artery origin in adults: 64-MDCT appearance. AJR Am J Roentgenol. 188(2):W138-46, 2007 2. Datta J et al: Anomalous coronary arteries in adults: depiction at multi-detector row CT angiography. Radiology. 235(3):812-8, 2005

Anomalous RCA Key Facts Imaging  Malignant o At risk of sudden cardiac death o Variable origin of right coronary artery o Passes between aorta and pulmonary artery  Benign variants o High take-off of coronary artery superior to right coronary cusp o Rarely from left sinus of Valsalva coursing posterior and inferior to aortic root  Cardiac multidetector CT is best imaging tool  MR in children and young patients (no ionizing radiation) Top Differential Diagnoses  Other coronary anomalies o Anomalous left main may have similar intraarterial course compared with malignant anomalous right coronary artery  Coronary artery fistula o Abnormal tortuous coronary artery but normal orgin from coronary ostium at sinus of Valsalva o Usually drains into right-sided cardiac chambers or pulmonary artery Pathology  Slit-like ostium and intramural course of proximal malignant anomalous right coronary artery is believed to have higher association with sudden cardiac death, especially if right coronary artery is dominant Clinical Issues  Usually asymptomatic  Malignant variants may present with sudden cardiac death or arrhythmia  Primary congenital coronary anomalies have incidence of 1-2%

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(Left) Illustration (posterior view, patient's right is on right side of image) shows the relationship between an anomalous RCA, aorta, and pulmonary artery. In the malignant variant, the RCA is between the aorta and pulmonary artery . In the rare benign variant, the RCA is posterior to the aorta . (Right) Thick VR oblique cardiac CTA shows the aberrant origin of an RCA with an interarterial course. The slit-like narrowing at the origin and the interarterial course are associated with increased risk for sudden death.

(Left) Coronal oblique maximum-intensity projection image shows a high origin of the RCA . The artery descends into the atrioventricular groove , which is its normal location. (Right) 3D volume-rendered image shows the high origin of the RCA above the sinotubular junction. The artery curves laterally before entering the atrioventricular groove . This is not considered a malignant course and is almost always an asymptomatic finding. P.8:25

TERMINOLOGY Definitions  Malignant variant: Right coronary artery (RCA) originates from left sinus of Valsalva and courses between aorta and pulmonary artery (interarterial)  Benign variants: RCA originates above sinotubular junction superior to right coronary cusp (common) or courses posterior and inferior to aortic root (very rare) IMAGING General Features  Best diagnostic clue o Absence of coronary artery ostium from right sinus of Valsalva, but RCA is present more distally  RCA has to be traced back to its abnormal origin to differentiate from ostial RCA occlusion  Location 640

Diagnostic Imaging Cardiovascular o

Origin of malignant anomalous RCA is variable  Typically arises from left coronary cusp between origin of left main coronary artery and anterior commissure  Rarely arises from left main  May arise superior to sinotubular junction, either above left sinus of Valsalva or above junction of right and left sinuses of Valsalva  Courses between anterior aspect of aortic root and posterior pulmonary artery wall  Morphology o May be oval in cross section, which has been suggested to be sign of compression; however, this view is controversial o Slit-like origin is associated with intramural course (high-risk feature) o If course crosses commissure, marsupialization may not be feasible o Dominance of vessel may relate to risk Imaging Recommendations  Best imaging tool o Cardiac multidetector CT o MR in children and young patients CT Findings  Cardiac gated CTA o ECG gating of CTA is necessary to allow depiction of coronary ostium and course of abnormal vessels o Volume-rendered 3D images can be helpful to demonstrate spatial relationship of aortic root and anomalous vessel MR Findings  Coronary anomalies can be evaluated with MR  Free of ionizing radiation  2D or 3D coronary MRA can reliably assess anatomy of coronary artery  ECG and respiratory gating are essential for motion-free imaging DIFFERENTIAL DIAGNOSIS Other Coronary Anomalies  Anomalous left main may have similar intraarterial course compared with malignant anomalous RCA Coronary Artery Fistula  Abnormal tortuous coronary artery but normal orgin from coronary ostium at sinus of Valsalva  Usually drains into right-sided cardiac chambers or pulmonary artery PATHOLOGY General Features  Associated abnormalities o Often isolated abnormality Gross Pathologic & Surgical Features  Slit-like ostium and intramural course of proximal malignant anomalous RCA is believed to have higher association with sudden cardiac death, especially if RCA is the dominant vessel CLINICAL ISSUES Presentation  Most common signs/symptoms o Often asymptomatic  Other signs/symptoms o Malignant variants may present with sudden cardiac death or arrhythmia Demographics  Gender o No gender predisposition  Epidemiology o Primary congenital coronary anomalies have incidence of 1-2% Natural History & Prognosis  Benign variant is typically clinically silent  Malignant coronary artery anomalies are 2nd most common cause of sudden death in young athletes DIAGNOSTIC CHECKLIST Image Interpretation Pearls  Right sinus of Valsalva without coronary artery ostium  Abnormal vessel course between aorta and pulmonary artery (malignant) 641

Diagnostic Imaging Cardiovascular SELECTED REFERENCES 1. Camarda J et al: Coronary artery abnormalities and sudden cardiac death. Pediatr Cardiol. 33(3):434-8, 2012 2. Young PM et al: Cardiac imaging: Part 2, normal, variant, and anomalous configurations of the coronary vasculature. AJR Am J Roentgenol. 197(4):816-26, 2011 3. Clemente A et al: Anomalous origin of the coronary arteries in children: diagnostic role of three-dimensional coronary MR angiography. Clin Imaging. 34(5):337-43, 2010 4. Prakken NH et al: Screening for proximal coronary artery anomalies with 3-dimensional MR coronary angiography. Int J Cardiovasc Imaging. 26(6):701-10, 2010 5. Kelle S et al: Coronary MR imaging: lumen and wall. Magn Reson Imaging Clin N Am. 17(1):145-58, 2009 6. Mikolich JR: Cardiac magnetic resonance imaging and coronary computed tomography angiography in the diagnosis of anomalous coronary artery. J Am Coll Cardiol. 53(5):456, 2009

Bland-White-Garland Syndrome Key Facts Terminology  Anomalous origin of left main coronary artery from pulmonary artery (ALCAPA)  Endothelial bud may persist on pulmonary sinus and attach to developing left main coronary artery Imaging  Left main coronary artery originates from pulmonary artery  Best noninvasive test: Coronary CTA o Cardiac MR is useful alternative  Best invasive test: Coronary angiography  Right heart catheterizations reveal left-to-right shunt in 75% of patients o Average reported shunt: 1.5  Number and extent of collaterals arising from right coronary artery are striking features of ALCAPA o Collaterals are typically very large Top Differential Diagnoses  Coronary fistula  Other coronary artery anomalies (e.g., anomalous right coronary artery from pulmonary artery) Clinical Issues  Most adults will present with left ventricular dysfunction and MR  Infants o Establishment of dual coronary perfusion is preferred o Direct reimplantation of anomalous coronary artery into aorta o Intrapulmonary conduit from left coronary artery to aorta (Takeuchi repair)  Adults o Ligation of left coronary artery and bypass graft  Many patients die from fatal ventricular dysrhythmias secondary to myocardial ischemia

(Left) Graphic shows a normal right coronary configuration from the right sinus of Valsalva and an anomalous origin of the left main coronary artery from the pulmonary artery (PA). (A = aorta; LAD = left anterior descending coronary 642

Diagnostic Imaging Cardiovascular artery; LCX = left circumflex coronary artery; RCA = right coronary artery.) (Right) Coronary CTA 3D image shows a markedly dilated RCA and multiple collateral vessels as well as a dilated left main coronary artery . (Courtesy M. Ichikawa, MD.)

(Left) Coronary CTA 3D image (same patient; cardiac chambers removed) shows anomalous left main coronary artery origin from PA. Note multiple collateral vessels and dilated RCA . Coronary arteries are dilated secondary to flow reversal from the systemic right to the low-pressure pulmonary system. (Courtesy M. Ichikawa, MD.) (Right) Coronary CTA 3D image (same patient) shows anomalous origin of left main coronary artery from PA. Note dilated RCA arising normally from the aorta. (Courtesy M. Ichikawa, MD.) P.8:27

TERMINOLOGY Definitions  Anomalous origin of left main coronary artery from pulmonary artery (ALCAPA)  Coronary arterial circulation is established by 45 days gestation in fetus o Possible causes of anomalous left coronary artery from pulmonary artery  Abnormal division of conotruncus  Abnormal involution of endothelial buds on sinuses of Valsalva  Endothelial bud may persist on pulmonary sinus and attach to developing left main coronary artery IMAGING General Features  Best diagnostic clue o Left main coronary artery originating from pulmonary artery  Location o Left coronary artery originates from pulmonary artery and then typically courses along its usual path down anterior interventricular groove  Size o Large right coronary artery and collaterals from right coronary artery with left-to-right shunt  Morphology o Number and extent of collaterals arising from right coronary artery are striking features of ALCAPA  Collaterals are typically very large Imaging Recommendations  Best imaging tool o Best noninvasive test: Coronary CTA o Cardiac MR is useful alternative  Does not currently have the spatial resolution of cardiac CTA  Does allow depiction of perfusion deficits  Late-enhancement gadolinium sequences allow detection of infarcted myocardium o Best invasive test: Invasive coronary angiography  Right heart catheterization reveals left-to-right shunt in 75% of patients  Average reported shunt: 1.5:1 643

Diagnostic Imaging Cardiovascular DIFFERENTIAL DIAGNOSIS Coronary Fistula  Normal origin of coronary artery  Abnormal distal vessel drainage o Drainage usually flows into right heart chambers or pulmonary artery Other Coronary Artery Anomalies  Anomalous right coronary artery from pulmonary artery (ARCAPA) PATHOLOGY General Features  Associated abnormalities o Coronary steal phenomenon o Myocardial ischemia o Myocardial infarction o Congestive heart failure o Mitral regurgitation CLINICAL ISSUES Presentation  Most common signs/symptoms o Most adults will present with left ventricular dysfunction  Other signs/symptoms o Small number of patients are asymptomatic o 96% have abnormal electrocardiogram o Syncope and sudden death may occur due to ventricular arrhythmias Demographics  Age o Rare in adults o 90% of patients present in infancy with heart failure  Gender o F:M > 2:1 Natural History & Prognosis  Degree of survival into adulthood depends on degree of collateralization from right coronary artery  Average age of sudden death in untreated adult patients with anomalous left coronary artery from pulmonary artery is 35 years  Many patients die from fatal ventricular dysrhythmias secondary to myocardial ischemia Treatment  Infants o Establishment of dual coronary perfusion is preferred  Direct reimplantation of anomalous coronary artery into aorta o Intrapulmonary conduit from left coronary artery to aorta (Takeuchi repair)  Adults o Ligation of left coronary artery and bypass graft DIAGNOSTIC CHECKLIST Image Interpretation Pearls  Absence of left main coronary artery origin from left sinus of Valsalva differentiates anomalous left coronary artery from pulmonary artery from coronary fistula SELECTED REFERENCES 1. Pursnani A et al: Coronary CTA assessment of coronary anomalies. J Cardiovasc Comput Tomogr. 6(1):48-59, 2012 2. Yau JM et al: Anomalous origin of the left coronary artery from the pulmonary artery in adults: a comprehensive review of 151 adult cases and a new diagnosis in a 53-year-old woman. Clin Cardiol. 34(4):204-10, 2011 3. Ichikawa M et al: Detection of Bland-White-Garland syndrome by multislice computed tomography in an elderly patient. Int J Cardiol. 114(2):288-90, 2007 4. Kim SY et al: Coronary artery anomalies: classification and ECG-gated multi-detector row CT findings with angiographic correlation. Radiographics. 26(2):317-33; discussion 333-4, 2006

Coronary Embolism Key Facts Terminology  Dislodged thrombus, tumor, cholesterol, air, or fat obstructing coronary artery 644

Diagnostic Imaging Cardiovascular Imaging  Cardiac gated CTA o Absence of culprit atherosclerotic lesion o May show subtle subendocardial perfusion defect o May demonstrate underlying pathology (myxoma, left atrial appendage thrombus, etc.) o May demonstrate patent foramen ovale (PFO), atrial septal defect (ASD), or other shunt responsible for paradoxical embolism  MR demonstrates focal subendocardial delayed hyperenhancement in presence of o PFO or ASD o Left atrial appendage thrombus o Left atrial myxoma or other mass  SSFP cine o Focal wall motion abnormality with otherwise maintained global left ventricular function  T2-weighted FSE o Edema adjacent to infarcted myocardium in the acute setting o Usually larger area than infarct on LGE MR  1st-pass perfusion o Focal subendocardial perfusion defect matching delayed hyperenhancement  Delayed enhancement o Focal area of delayed hyperenhancement based on subendocardial myocardium  Invasive coronary angiography usually demonstrates clean coronary arteries Diagnostic Checklist  Coronary embolus is diagnosis of exclusion  Coronary artery disease with acute coronary syndrome and myocarditis need to be excluded

(Left) Short-axis LGE MR 2 days after sudden onset of acute chest pain shows focal subendocardial delayed hyperenhancement , which is nearly transmural and represents a focal myocardial infarct in a subset of the RCA territory (PLV branch). No other foci of delayed enhancement are present. (Right) Short-axis noncontrast T2WI FSE MR shows an area of T2 hyperintensity that is larger than the infarcted myocardium seen on LGE MR, indicating periinfarct myocardial edema in a recent infarct.

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(Left) Oblique MPR of right coronary artery and portion of posterior left ventricular branch (PLV) shows absence of any plaque or stenosis. No culprit lesion (atherosclerotic plaque ± rupture) is identified. (Right) Short-axis SSFP MR performed after contrast administration demonstrates high signal in the same location as above , which is due to a combination of hyperemic enhancement and edema. Cine images showed focal akinesis in this segment, consistent with stunned myocardium. P.8:29

TERMINOLOGY Definitions  Dislodged thrombus, tumor, cholesterol, air, or fat obstructing coronary artery IMAGING General Features  Best diagnostic clue o MR demonstrates focal subendocardial delayed hyperenhancement in presence of  Patent foramen ovale (PFO) or atrial septal defect (ASD)  Left atrial appendage (LAA) thrombus  Left atrial (LA) myxoma or other mass CT Findings  Cardiac gated CTA o Absence of culprit atherosclerotic lesion  Often clean coronary arteries o May show subtle subendocardial perfusion defect o Regional akinesis (stunning) but maintained global function o May demonstrate underlying pathology (myxoma, LAA thrombus, etc.) o May demonstrate PFO, ASD, or other shunt responsible for paradoxical embolism MR Findings  SSFP white blood cine o Focal wall motion abnormality with otherwise maintained global left ventricular (LV) function o If performed after gadolinium administration, may demonstrate area of hyperenhancement o May demonstrate edema  T2-weighted FSE o Edema adjacent to infarcted myocardium in the acute setting  Usually larger area than infarct on LGE MR  1st-pass perfusion o Focal subendocardial perfusion defect matching delayed hyperenhancement  Delayed enhancement o Focal area of delayed hyperenhancement based on subendocardial myocardium Angiographic Findings  Invasive coronary angiography usually demonstrates clean coronary arteries o May demonstrate distal intraluminal filling defect 646

Diagnostic Imaging Cardiovascular Imaging Recommendations  Best imaging tool o Cardiac MR is best modality to suggest diagnosis  Protocol advice o Include T1 pre- and post-contrast images to exclude myocarditis DIFFERENTIAL DIAGNOSIS Acute Myocardial Infarction Due to Atherosclerotic Coronary Artery Disease  Associated coronary artery disease Myocarditis  Clean coronary arteries but elevated cardiac markers  Linear mid-myocardial or subepicardial hyperenhancement  Increased relative global enhancement (myocardium vs. skeletal muscle) PATHOLOGY General Features  Etiology o Dislodged thrombus from deep venous thrombosis (DVT) or fat from long bone after fracture o Left atrial myxoma or other neoplasm o Plaque or cholesterol dislodged during coronary angioplasty  Associated abnormalities o DVT, left atrial appendix thrombus, LA myxoma or other tumor o Septal pouch in left atrium Gross Pathologic & Surgical Features  Usually small focal myocardial necrosis based on subendocardial myocardium CLINICAL ISSUES Presentation  Most common signs/symptoms o Usually atypical presentation due to small area of infarction o Chest pain; pain in chin, left arm, or epigastrium  Other signs/symptoms o Borderline elevated cardiac enzymes Demographics  Epidemiology o Rare Treatment  Treat underlying cause o ASD closure device, resection of myxoma, treat DVT DIAGNOSTIC CHECKLIST Consider  Coronary embolus is diagnosis of exclusion o Coronary artery disease with acute coronary syndrome and myocarditis need to be excluded SELECTED REFERENCES 1. Breithardt OA et al: A coronary embolus originating from the interatrial septum. Eur Heart J. 27(23):2745, 2006 2. Duman D et al: Paradoxical mesentery embolism and silent myocardial infarction in primary antiphospholipid syndrome: a case report. Heart Surg Forum. 9(2):E592-4, 2006 3. Rana O et al: Images in clinical medicine. Cholesterol emboli after coronary angioplasty. N Engl J Med. 354(12):1294, 2006

Coronary Artery Aneurysm Key Facts Terminology  Coronary artery diameter > 1.5× normal adjacent segments, involving < 50% of vessel  Coronary artery ectasia: Diffuse coronary artery dilatation Imaging  Coronary CTA o Evaluation of coronary aneurysm morphology, thrombosis, dissection o Calcification frequently present in atherosclerosis o Size underestimation with mural thrombus or dissection  MR 647

Diagnostic Imaging Cardiovascular o Preferred modality when surveillance required o Calcification difficult to detect o Stents and clips may degrade image quality  Angiography: May underestimate size if mural thrombus or dissection is present Top Differential Diagnoses  Coronary fistula  Coronary pseudoaneurysm Pathology  Atherosclerosis is most common cause in USA o Right coronary artery is typically affected  Kawasaki disease is most common cause worldwide o Left main artery is most commonly affected Clinical Issues  Most patients are asymptomatic  May present with acute coronary syndrome and heart failure  Treatment: Anticoagulants, antiplatelets, surgery Diagnostic Checklist  Consider coronary artery aneurysm in patients < 20 years old with angina or acute myocardial infarction

(Left) Axial coronary CTA of a 19-year-old female with leukemia and acute chest pain shows a focal right coronary artery aneurysm and associated hemopericardium . (Right) Oblique CTA of the same patient shows focal disruption of the aneurysm, which had enlarged over the previous 2 days. Aneurysm rupture is a rare complication of coronary artery aneurysm. Aneurysm enlargement and rupture are indications for intervention. This patient was treated with a covered coronary stent.

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Diagnostic Imaging Cardiovascular (Left) Axial coronary CTA of a 26-year-old woman with Kawasaki disease shows dilatation of the right and left main coronary arteries. Note peripheral calcification of the enlarged left main coronary artery. (Right) 3D volumerendered image from a coronary CTA of a 42-year-old man with Kawasaki disease shows dilatation of the left anterior descending and left circumflex coronary arteries. Coronary artery aneurysms occur in 15-25% of untreated patients with Kawasaki disease. P.8:31

TERMINOLOGY Definitions  Coronary artery diameter > 1.5× normal adjacent segments, involving < 50% of vessel IMAGING General Features  Best diagnostic clue o Dilatation of coronary artery  Morphology o Fusiform or saccular dilatation  May exhibit thrombus or dissection o Coronary artery ectasia refers to diffuse dilation CT Findings  Cardiac gated CTA o Evaluation of coronary aneurysm morphology, thrombosis, dissection o Calcification is frequently present in atherosclerosis MR Findings  Available coronary angiography sequences o Lumen is dark on double IR-FSE o Lumen is bright on GRE or b-SSFP in absence of thrombus  May be preferred modality when surveillance required  Calcification is difficult to detect  Stents and clips may degrade image quality Echocardiographic Findings  Echocardiogram o Aneurysm detection in proximal coronary arteries Angiographic Findings  Fusiform and saccular dilatation of coronary arteries  May underestimate size if mural thrombus or dissection is present Imaging Recommendations  Best imaging tool o Gated coronary CTA is imaging modality of choice DIFFERENTIAL DIAGNOSIS Coronary Fistula  Dilated vessel associated with fistula  Coronary ectasia proximal to fistula if large shunt or steal physiology is present Coronary Pseudoaneurysm  Frequently secondary to chest trauma or catheter-based intervention PATHOLOGY General Features  Etiology o Atherosclerosis is most common cause in USA  Right coronary artery is most commonly affected, followed by left anterior descending, left circumflex, and left main coronary arteries o Kawasaki disease is most common cause worldwide  Coronary artery aneurysm develops in 15-25% of untreated affected children  May regress with treatment  Left main coronary artery most commonly involved o Takayasu arteritis (12% have coronary involvement) o Connective tissue disease (systemic lupus erythematosus, Marfan, Behçet) o Other: Congenital, trauma, catheter-based intervention, mycotic emboli, cocaine use 649

Diagnostic Imaging Cardiovascular Staging, Grading, & Classification  True aneurysm walls consist of all 3 vessel wall layers  Pseudoaneurysms have ≤ 2 intact walls  > 20 mm diameter in adults is considered “giant” Gross Pathologic & Surgical Features  Dilatation of coronary artery, may contain thrombus Microscopic Features  Atherosclerotic coronary aneurysms may exhibit thinning or destruction of media CLINICAL ISSUES Presentation  Most common signs/symptoms o Most patients are asymptomatic o Acute coronary syndrome and heart failure may be caused by aneurysm or concurrent disease  Clinical profile o Can result in thrombosis and myocardial infarction Demographics  Gender o M:F = ˜ 4:1  Epidemiology o Present in ˜ 5% of angiograms, 1.5% of necropsies Natural History & Prognosis  Related to severity of concomitant obstructive disease in patients with atherosclerosis  Rupture has been reported but is rare Treatment  Anticoagulants, antiplatelet therapy  Surgical intervention if enlargement, embolization, or obstruction o Bypass and exclusion of aneurysm o Covered stent graft  Kawasaki disease is typically treated with high-dose intravenous γ-globulin and aspirin DIAGNOSTIC CHECKLIST Consider  Coronary artery aneurysm in patients < 20 years old presenting with angina or acute myocardial infarction SELECTED REFERENCES 1. Pursnani A et al: Coronary CTA assessment of coronary anomalies. J Cardiovasc Comput Tomogr. 6(1):48-59, 2012 2. Díaz-Zamudio M et al: Coronary artery aneurysms and ectasia: role of coronary CT angiography. Radiographics. 29(7):1939-54, 2009

Coronary Calcification Key Facts Terminology  With the possible exception of patients with renal failure, who may develop medial calcification, coronary calcium is always in intima and, hence, associated with coronary atherosclerotic plaque  Nonenhanced CT imaging and quantitative software are used to determine coronary artery calcium score (CACS, Agatston score) Imaging  ECG-gated nonenhanced cardiac CT is used to detect and quantify coronary calcium  By convention, threshold for identification of calcium is 130 HU at a tube potential of 120 kV  Identification of ≥ 3 contiguous pixels with attenuation > 130 HU in wall of a coronary artery is defined as calcified coronary lesions  Agatston score, determined from plaque area and coefficient that depends on peak CT attenuation, is widely used to quantify coronary calcium Top Differential Diagnoses  Coronary artery stent  Mitral annular calcification  Aortic wall calcification Clinical Issues  In asymptomatic individuals, presence and extent of coronary calcium correlate to risk of future cardiovascular events 650

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 

Coronary calcium is therefore part of some risk assessment algorithms used to select candidates for cholesterol-lowering drug therapy Interscan variability is high, especially for low scores Repeat testing is not recommended

(Left) Nonenhanced CT is used for visualizing coronary calcification. By international standard, 120 kV are used for acquisition, and the reconstructed slice thickness is 3 mm. Two small calcifications of the proximal left anterior descending coronary artery are detectable. (Right) Coronary calcium is also visible on contrast-enhanced coronary CT angiography. Here, a small calcification of the proximal left anterior descending coronary artery is present .

(Left) In a fluoroscopic frame (left), calcification is detectable as a grayish shadow . After injection of contrast agent (right), the calcium deposit next to the contrast-filled lumen is better visualized. (Right) Intravascular ultrasound (IVUS) is the most sensitive in vivo method for identifying coronary calcifications. They appear bright and cause shadowing . The less intensive shadowing is caused by the intracoronary wire that is used to guide the IVUS catheter (present in all IVUS images). P.8:33

TERMINOLOGY Definitions  Deposition of calcium hydroxyapatite in coronary arteries o Coronary calcium is always in intima and hence associated with coronary atherosclerotic plaque o Possible exception: Patients with renal failure may develop medial calcification  Nonenhanced CT imaging and quantitative software are used to determine coronary artery calcium score (CACS, Agatston score) 651

Diagnostic Imaging Cardiovascular IMAGING Radiographic Findings  Radiography o Low sensitivity Fluoroscopic Findings  Requires specific angulations and has low sensitivity for coronary calcium CT Findings  NECT o By convention, threshold for identification of calcium is 130 HU at tube potential of 120 kVp o Agatston score is widely used to quantify coronary calcium  Requires reconstruction of 3 mm thick slices  Lesions must have area of ≥ 3 contiguous pixels > 130 HU  For each lesion, a cofactor is derived from its peak attenuation  Cofactor 1 for 131-200 HU  Cofactor 2 for 201-300 HU  Cofactor 3 for peak 301-400 HU  Cofactor 4 for peak 401+ HU  Agatston score for each plaque in each slice is product of plaque area and cofactor  Scores for all lesions in all slices are summarized to obtain per-vessel and per-patient Agatston scores o Alternative methods for scoring include calcified plaque volume and calcified mass (which requires a phantom for reference) o Vast majority of published scientific literature uses Agatston score  Contrast-enhanced CT angiography o Calcified plaques can also be detected in contrast-enhanced coronary CT angiography o Very small calcifications may be missed due to CT attenuation similar to contrast-enhanced lumen o Higher spatial resolution and overlap of CT attenuation values with contrast-enhanced lumen make use of Agatston score impossible in CT angiography Imaging Recommendations  Best imaging tool o Multidetector-row CT  Best diagnostic tool o Nonenhanced, ECG-gated CT imaging o Identification of ≥ 3 contiguous pixels with attenuation > 130 HU in wall of a coronary artery is defined as coronary calcium DIFFERENTIAL DIAGNOSIS Coronary Artery Stent  On nonenhanced CT, a coronary stent can have similar appearance to coronary calcium Mitral Annular Calcification  Corresponds to location of mitral valve annulus  Can be misinterpreted as left circumflex coronary artery calcification Calcification of Aortic Wall  Must avoid aortic wall calcification and ostial coronary calcium in calculation of CACS Calcification of Old Myocardial Infarction  Calcification in myocardium o Although rarely in close anatomic proximity to a coronary artery Pericardial Calcification  Seen in presence of constrictive pericarditis PATHOLOGY General Features  Calcium found at advanced stage of atherosclerotic plaque development o Calcium hydroxyapatite deposition involves active inflammation and processes similar to osteogenesis  Amount of calcified plaque roughly correlates to total amount of plaque o Calcified plaque represents ˜ 20% of total plaque burden  Coronary atherosclerotic plaque and even stenosis can be present even when calcium is absent o Especially in patients who are  Young 652

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Female With acute symptoms

CLINICAL ISSUES Presentation  Coronary calcium causes no symptoms and is present in majority of adults > 50 years of age  In asymptomatic individuals, presence and extent of coronary calcium correlate to risk of future cardiovascular events  Coronary calcium part of some risk assessment algorithms is used to select candidates for cholesterollowering drug therapy o Individuals with no risk factors  Low risk  Do not require further testing o Individuals with established cardiovascular disease or diabetes  High risk  Require lipid-lowering treatment  Imaging is not considered helpful for risk stratification o Coronary calcium is considered most useful in individuals with intermediate risk (e.g., 10-year risk of coronary artery disease = 10-20%) according to Framingham risk score P.8:34 

Frequently used risk categories for coronary calcium o CACS 0 o CACS 1-100 o CACS 100-399 o CACS 400-999 o CACS ≥1,000  Typically, coronary calcium percentile is included in report o Puts measured amount of calcium in perspective to distribution found in individuals of same gender and age class o Online reference values web tool calculators are available for percentile calculation, such as from the Multi-Ethnic Study of Atherosclerosis (MESA) o Arterial age can also be calculated from coronary artery calcium scores  Arterial age expresses an estimated risk-equivalent of coronary artery calcium Demographics  Age o Incidence increases from only a few percent in 2nd decade of life to nearly 100% by 8th decade  Gender o General incidence in women is similar to that in men who are a decade younger o Separation in prevalence with age is eliminated by age 70 Natural History & Prognosis  Progression of CACS is measured as percentage of baseline score  Annual CACS progression: 14-27% o Average: 24%  Rapid progression has been connected to an elevated risk for coronary artery disease events  Interscan variability is high, especially for low scores, and significantly limits utility of repeat testing Treatment  Presence of coronary calcium in conjunction with other risk factors may prompt initiation of lipid-lowering therapy  Statins are not proven to affect CACS progression DIAGNOSTIC CHECKLIST Consider  Reconstructing full field of view images to evaluate extracardiac structures o Lung nodules require follow-up in 2-5% of cases Image Interpretation Pearls  Avoid measuring plaque in aortic wall near origins of right coronary artery and left main coronary artery  Avoid confusing mitral annular calcification with left circumflex coronary artery calcification SELECTED REFERENCES 653

Diagnostic Imaging Cardiovascular 1. Arad Y et al: Treatment of asymptomatic adults with elevated coronary calcium scores with atorvastatin, vitamin C, and vitamin E: the St. Francis Heart Study randomized clinical trial. J Am Coll Cardiol. 46(1):166-72, 2005. Erratum in: J Am Coll Cardiol. 58(17):1832, 2011 2. Erbel R et al: Coronary risk stratification, discrimination, and reclassification improvement based on quantification of subclinical coronary atherosclerosis: the Heinz Nixdorf Recall study. J Am Coll Cardiol. 56(17):1397-406, 2010 3. Budoff MJ et al: Cardiovascular events with absent or minimal coronary calcification: the Multi-Ethnic Study of Atherosclerosis (MESA). Am Heart J. 158(4):554-61, 2009 4. Detrano R et al: Coronary calcium as a predictor of coronary events in four racial or ethnic groups. N Engl J Med. 358(13):1336-45, 2008 5. Fraker TD Jr et al: 2007 chronic angina focused update of the ACC/AHA 2002 guidelines for the management of patients with chronic stable angina: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines Writing Group to develop the focused update of the 2002 guidelines for the management of patients with chronic stable angina. J Am Coll Cardiol. 50(23):2264-74, 2007. Erratum in: J Am Coll Cardiol. 50(23):e1, 2007 6. Greenland P et al: ACCF/AHA 2007 clinical expert consensus document on coronary artery calcium scoring by computed tomography in global cardiovascular risk assessment and in evaluation of patients with chest pain: a report of the American College of Cardiology Foundation Clinical Expert Consensus Task Force (ACCF/AHA Writing Committee to Update the 2000 Expert Consensus Document on Electron Beam Computed Tomography) developed in collaboration with the Society of Atherosclerosis Imaging and Prevention and the Society of Cardiovascular Computed Tomography. J Am Coll Cardiol. 49(3):378-402, 2007 7. Budoff MJ et al: Assessment of coronary artery disease by cardiac computed tomography: a scientific statement from the American Heart Association Committee on Cardiovascular Imaging and Intervention, Council on Cardiovascular Radiology and Intervention, and Committee on Cardiac Imaging, Council on Clinical Cardiology. Circulation. 114(16):1761-91, 2006 8. McClelland RL et al: Distribution of coronary artery calcium by race, gender, and age: results from the Multi-Ethnic Study of Atherosclerosis (MESA). Circulation. 113(1):30-7, 2006 9. Schmermund A et al: Natural history and topographic pattern of progression of coronary calcification in symptomatic patients: An electron-beam CT study. Arterioscler Thromb Vasc Biol. 21(3):421-6, 2001 10. Agatston AS et al: Quantification of coronary artery calcium using ultrafast computed tomography. J Am Coll Cardiol. 15(4):827-32, 1990 P.8:35

Image Gallery

(Left) Calcifications of the left anterior descending coronary artery and diagonal branch are present and clearly detectable on this nonenhanced ECG-triggered CT of the coronary arteries (120 kV, 3 mm slice thickness). (Right) Calcium score CT (120 kV, 3.0 mm slice thickness) shows calcification of the left circumflex (LCX) coronary artery in the atrioventricular groove. Occasionally, beam hardening artifact or mitral annular calcification can mimic calcification in this area.

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(Left) Calcification of the mid right coronary artery is present and clearly detectable on this nonenhanced ECGtriggered CT of the coronary arteries (120 kV, 3 mm slice thickness). (Right) Calcification of the distal right coronary artery is present and clearly detectable on this nonenhanced ECG-triggered CT of the coronary arteries (120 kV, 3 mm slice thickness) from the same patient.

(Left) By consensus, calcifications of the coronary ostia (here, ostium of the left main [LM]) are not included in coronary calcium evaluation. It should be mentioned in the report but not counted toward the coronary calcium score. At the LM bifurcation, calcification of left anterior descending and LCX is present. (Right) Calcification of the mitral annulus is often present and could be misinterpreted as LCX calcification. Calcification of the mid right coronary artery is present.

Coronary Atherosclerotic Plaque Key Facts Terminology  Deposit that develops in intimal layer of coronary arteries and consists of lipids, fibrous tissue, smooth muscle cells, and calcium  Atherosclerotic plaque can develop into stenotic lesion but may not necessarily be associated with relevant reduction of coronary lumen Imaging  Coronary calcium is highly specific and fairly sensitive for presence of coronary atherosclerotic plaque  Coronary CT angiography can detect coronary plaque but only if image quality is optimal  Coronary MR has potential for plaque visualization and characterization

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Invasive coronary angiography underestimates the presence and extent of coronary atherosclerotic plaque and must be complemented by intravascular ultrasound for plaque assessment Top Differential Diagnoses  Myocardial bridge  Coronary vasculopathy post heart transplant Clinical Issues  Most coronary atherosclerotic plaques remain clinically silent  Sudden plaque rupture (or, less frequently, erosion) with subsequent luminal thrombosis leads to acute coronary event  Slow plaque growth, sometimes as a consequence of repeated “healed” rupture or intraplaque hemorrhage, can lead to occurrence of coronary artery stenosis and stable coronary artery disease

(Left) Contrast-enhanced coronary CT angiography shows calcified and noncalcified components of a partially calcified atherosclerotic plaque present in the proximal left anterior descending coronary artery. (Right) Contrastenhanced coronary CT angiography in the same patient shows a cross-sectional view of the proximal left anterior descending coronary artery. A noncalcified plaque is clearly detectable .

(Left) Invasive coronary angiography (same patient) shows an atherosclerotic plaque detected on CT. Only a very mild narrowing of the coronary artery lumen is present. Note that even a pronounced plaque is not necessarily associated with a relevant luminal stenosis. (Right) Intracoronary ultrasound of the proximal left anterior descending coronary artery (same patient) provides a cross-sectional view of the vessel and demonstrates the presence of a pronounced noncalcified coronary atherosclerotic plaque . P.8:37

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Diagnostic Imaging Cardiovascular TERMINOLOGY Definitions  Deposit that develops in intimal layer of coronary arteries and consists of lipids, fibrous tissue, smooth muscle cells, and calcium o Necrotic core can be present, covered by a fibrous cap o Atherosclerotic plaque can develop into coronary artery stenosis o Most plaques are not associated with relevant luminal stenosis o Acute coronary syndromes (myocardial infarction and unstable angina) occur as a result of plaque rupture with subsequent thrombosis of vessel lumen  Immediately before rupture, plaques are often not associated with relevant luminal stenosis IMAGING General Features  Location o Can occur in any part of coronary arterial tree but is most frequently localized in proximal coronary segments  Size o Plaque size is not related to degree of luminal narrowing o “Positive remodeling” describes a phenomenon wherein vessel outwardly expands as plaque builds up in vessel wall  Degree of luminal narrowing therefore depends both on plaque size and on degree of remodeling  Morphology o Plaques generally consist of a lipid-rich necrotic core surrounded by fibrous tissue, smooth muscle cells, and calcification  Typically covered by a fibrous cap toward vessel lumen  Thin fibrous caps and large necrotic cores are among factors that predispose plaques to rupture, which may result into an acute coronary syndrome  Hence, plaques with these features are called vulnerable plaques or thin-cap fibroatheromas  Most acute coronary events are caused by rupture of nonstenotic plaques because such plaques are substantially more prevalent than stenotic lesions  However, risk of a single stenotic lesion rupturing and leading to acute event is higher than risk of a single nonstenotic plaque  Plaque and stenosis o Not all plaques are associated with luminal stenosis o Detection of plaque therefore requires direct visualization CT Findings  NECT o Coronary calcium is highly specific and fairly sensitive for presence of coronary atherosclerotic plaque o Amount of coronary calcium correlates with overall amount of plaques o Amount of coronary calcium is associated with risk of future acute coronary syndromes or death  Coronary calcium assessment is recommended for risk stratification purposes in some asymptomatic individuals, especially when need for lipid-lowering therapy cannot be clearly determined otherwise o Presence of coronary calcium is not necessarily associated with presence of luminal stenosis  CTA o Can identify calcified and noncalcified plaques o Some CT features are associated with plaque vulnerability  Positive remodeling  Large plaque volume  Low CT attenuation  Absence of severe calcification  “Napkin ring” sign: Ring-like rim of high attenuation around a central area of low attenuation o Extremely high image quality is required to identify and characterize noncalcified coronary plaque on CTA  Reliable quantification of noncalcified plaque is not possible on CT 657

Diagnostic Imaging Cardiovascular MR Findings  Coronary MR has potential for plaque visualization and characterization o Spin-echo T2-weighted imaging  Intraplaque lipid appears hyperintense (bright)  Muscularis and external elastic laminae are hypointense (dark)  Adventitial fat (triglyceride rich) is hyperintense o Multispectral imaging  T1WI, T2WI, TOF, PDWI techniques combined to identify components  Identify calcium, lipid, and hemorrhage  Spatial resolution is limited, and image quality is too unreliable for clinical applications Echocardiographic Findings  Echocardiogram o Transthoracic or transesophageal echocardiography  Not a suitable routine imaging technique, although proximal coronary lesions are occasionally detected  Intravascular ultrasound (IVUS) can detect diseased segments in angiographically normal coronaries o Invasive technique done at time of coronary catheterization o Normal intima is not visible o Lesion extent: From lumen to external elastic lamina o External elastic lamina; echolucent border o Can differentiate calcified from noncalcified plaque o Detects plaque rupture and erosion with subsequent thrombus formation o Can guide percutaneous coronary interventions  Enables optimal selection of stent size  Prevents incomplete apposition  Detects dissection o Plaque characterization limited Angiographic Findings  Invasive coronary angiography o Nonstenotic plaque may not be appreciable on invasive coronary angiography o Mild lumen reductions in invasive angiography indicate presence of plaque, but size and extent of plaque cannot not be determined P.8:38

o o

Haziness of a stenotic segment in coronary angiography suggests presence of thrombus Washed-out cavities can sometimes be detected as a consequence of plaque rupture (healed rupture or plaque ulceration) o Invasive coronary angiography can be complemented by IVUS, optical coherence tomography (OCT), or angioscopy to detect and characterize nonstenotic plaque Other Modality Findings  OCT findings o Intraluminal OCT catheter is placed at time of cardiac catheterization o Examines interferogram generated by backscatter of coherent light source o High-resolution images; can measure on scale of microns o Requires blood-free vessel lumen: Saline or perfluorocarbon flush o Penetrates only a few mm into vessel wall o Very infrequently used in clinical routine  Angioscopy findings o Optical imaging catheter is placed at time of cardiac catheterization o Requires saline flush to clear blood from field o Distinguishes lesion type  White lesion: Thick fibrous cap, predominantly fibrous lesion  Yellow surface: Lipid-containing lesion with thin collagenous cap; more likely to rupture o Not used in clinical routine Imaging Recommendations  Best imaging tool o Invasive: Invasive coronary angiography in combination with IVUS or OCT  Invasive angiography alone underestimates plaque burden 658

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Noninvasive: Coronary CTA  Ability to visualize plaque heavily depends on image quality o No single imaging modality can reliably detect, quantify, and characterize coronary atherosclerotic plaque DIFFERENTIAL DIAGNOSIS Myocardial Bridge  Intramyocardial course of coronary artery with various degrees of systolic narrowing Coronary Vasculopathy Post Heart Transplant  While atherosclerotic plaques are typically eccentric and focal, diffuse and concentric thickening of coronary artery wall can be a consequence of heart transplantation o Transplant recipients are also predisposed to conventional atherosclerosis PATHOLOGY General Features  Detection of plaque o Multiple stages of development: From fatty streaks to complex lesions with hemorrhage and calcification (type 1 through 5)  Histopathology features of vulnerable plaque o Large plaque volume o Thin fibrous cap (< 65 µm) o Large noncellular lipid core o Inflammation in cap and at cap shoulders o Increased monocyte and macrophage content o Expression of matrix metalloproteinase (with collagenase activity) CLINICAL ISSUES Presentation  Most coronary atherosclerotic plaques remain clinically silent  Sudden plaque rupture (or, less frequently, erosion) with subsequent luminal thrombosis leads to acute coronary event  Slow plaque growth, sometimes as a consequence of repeated “healed” rupture or intraplaque hemorrhage, can lead to occurrence of coronary artery stenosis and stable coronary artery disease Treatment  Lipid-lowering medication to stabilize plaque and prevent further growth  Antiplatelet therapy (e.g., aspirin) to avoid coronary thrombosis in case of plaque rupture or erosion o No data to support medication if plaque is incidentally detected in noninvasive imaging o Revascularization (e.g., percutaneous coronary intervention) is not justified for plaques that are not associated with hemodynamically relevant luminal stenosis DIAGNOSTIC CHECKLIST Consider  Invasive coronary angiography underestimates the presence and extent of coronary atherosclerotic plaque  Coronary CT angiography can detect coronary plaque but only if image quality is optimal  Ability to perform plaque characterization by any imaging modality is limited SELECTED REFERENCES 1. Gerretsen S et al: Detection of coronary plaques using MR coronary vessel wall imaging: validation of findings with intravascular ultrasound. Eur Radiol. 23(1):115-24, 2013 2. Voros S et al: Coronary atherosclerosis imaging by coronary CT angiography: current status, correlation with intravascular interrogation and meta-analysis. JACC Cardiovasc Imaging. 4(5):537-48, 2011 3. Achenbach S et al: Imaging of coronary atherosclerosis by computed tomography. Eur Heart J. 31(12):1442-8, 2010 4. Guédès A et al: Intravascular ultrasound assessment of atherosclerosis. Curr Atheroscler Rep. 6(3):219-24, 2004 5. Goldstein JA: Angiographic plaque complexity: the tip of the unstable plaque iceberg. J Am Coll Cardiol. 39(9):14647, 2002 6. Gutstein DE et al: Pathophysiology and clinical significance of atherosclerotic plaque rupture. Cardiovasc Res. 41(2):323-33, 1999 P.8:39

Image Gallery

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(Left) Contrast-enhanced coronary CT angiography shows a completely noncalcified, nonobstructive coronary atherosclerotic plaque in the proximal left anterior descending coronary artery. The plaque is eccentric and displays positive remodeling. (Right) Intracoronary ultrasound in the same patient shows the coronary atherosclerotic plaque previously depicted by CT angiography.

(Left) Contrast-enhanced coronary CT angiography shows a partially calcified, nonobstructive coronary atherosclerotic plaque in the proximal left anterior descending coronary artery. (Right) Intracoronary ultrasound in the same patient shows the partially calcified coronary atherosclerotic plaque previously depicted by CT angiography.

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(Left) Comparison of various types of coronary atherosclerotic plaques, as seen on contrast-enhanced computed tomography, shows a noncalcified plaque , a partially calcified plaque with noncalcified and calcified components, and a completely calcified plaque . (Right) CT angiography demonstrates a vulnerable plaque with low density, positive remodeling, and spotty calcification . P.8:40

(Left) Coronary CT angiography demonstrates a very large, mostly noncalcified plaque of the left main and left anterior descending coronary arteries. Even large amounts of a coronary atherosclerotic plaque must not necessarily be associated with a significant luminal stenosis. (Right) Invasive coronary angiography in the same patient demonstrates absence of detectable luminal narrowing at the site of coronary atherosclerotic plaque that had been detected by CT.

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(Left) Contrast-enhanced coronary CT angiography shows a noncalcified coronary atherosclerotic plaque in the proximal left anterior descending coronary artery with pronounced positive remodeling . (Right) Contrastenhanced coronary CT angiography multiplanar reconstruction in the same patient demonstrates a generated cross section of the plaque, which displays pronounced positive remodeling of the eccentric plaque .

(Left) Contrast-enhanced coronary CT angiography shows a transaxial image with an ulcerated plaque. A small cavity caused by a previous plaque rupture is now filled with contrast agent . (Right) Invasive coronary angiography in anteroposterior cranial projection in the same patient shows the ulcerated plaque that caused a mild to moderate coronary artery stenosis . P.8:41

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(Left) Contrast-enhanced coronary CT angiography shows a curved multiplanar reconstruction of a right coronary artery (proximal and mid segments). Note the ruptured plaque, which has a large cavity filled with contrast agent . (Right) Contrast-enhanced coronary CT angiography (oblique maximum-intensity projection; same patient) shows the mid right coronary artery, in which a ruptured plaque can be detected . Note a smaller, calcified plaque in the proximal right coronary artery.

(Left) Invasive coronary angiography in the same patient in a projection with a similar orientation shows the ulcerated portion of the plaque filling with contrast material. (Right) Intravascular ultrasound in the same patient shows an eccentric noncalcified coronary atherosclerotic plaque and, as a consequence of plaque rupture, a washed-out cavity filled with blood .

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(Left) Assessing a coronary atherosclerotic plaque via contrast-enhanced computed tomography can be difficult. Because of noise , a noncalcified plaque can be neither reliably detected nor excluded on this image. (Right) Here, slight motion unsharpness makes it impossible to reliably detect or rule out the presence of small atherosclerotic plaque deposits. Myocardial bridging can mimic a plaque with positive remodeling.

Coronary Thrombosis Key Facts Terminology Obstruction/occlusion of a coronary artery by thrombus, usually due to plaque rupture Causes acute coronary syndrome ST-elevation myocardial infarction Non-ST elevation myocardial infarction Unstable angina Imaging Coronary angiography shows complete occlusion or stenosis of a coronary artery Thrombus may be visible as filling defect or haziness if occlusion is not complete Occasionally, a coronary artery side branch that is completely occluded at its origin may not be visible in invasive angiography; diagnosis may be missed Coronary CTA shows low-density material within coronary lumen Thrombus may completely occlude coronary lumen Thrombus may be surrounded by contrast agent Often pronounced positive remodeling (i.e., increase in coronary artery diameter) at site of thrombosis Top Differential Diagnoses Similar clinical symptoms Aortic dissection Pulmonary embolism Similar angiographic appearance Stable coronary artery disease Coronary dissection Embolic coronary occlusion (e.g., thrombus, endocarditis) Clinical Issues Common signs/symptoms: Acute chest pain, dyspnea High mortality if untreated Can occur simultaneously at multiple sites in coronary artery tree

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(Left) Graphic depicts the pathogenesis of intracoronary thrombosis. Atherosclerotic plaque (top right) can develop in a normal coronary arterial wall (top left). The fibrous cap that covers the necrotic core of plaque can rupture (bottom left). When thrombogenic plaque material contacts blood stream (bottom right), thrombosis occurs instantaneously, and an acute coronary syndrome may ensue. (Right) Invasive coronary angiography shows plaque rupture with a subsequent thrombus in the left circumflex artery.

(Left) Typical CT appearance in the same patient shows an acute obstructive focal lesion with an enlarged vessel diameter. The lumen is filled with low-density material . (Right) Intracoronary thrombus aspiration during invasive angiography in the same patient produced several small thrombotic particles . P.8:43

TERMINOLOGY Definitions Obstruction/occlusion of a coronary artery by thrombus Usually the consequence of plaque rupture IMAGING General Features Best diagnostic clue Abrupt cutoff of coronary lumen on coronary angiography accompanied by acute symptoms Thrombus may be visible as filling defect or haziness if occlusion is not complete CT Findings CTA Coronary CTA shows low-density material within coronary lumen 665

Diagnostic Imaging Cardiovascular May completely occlude coronary lumen May be surrounded by contrast agent Often pronounced positive remodeling (i.e., increase in coronary artery diameter) at site of thrombosis MR Findings T2WI T2 hyperintensity corresponds to peri-infarct edema MR 3D free-breathing navigator-gated sequences using fibrin-binding molecular MR contrast agents is being developed May aid in thrombus detection in the future Late gadolinium enhancement imaging May exclude or detect and quantify transmural extent of myocardial infarction resulting from acute coronary thrombosis SSFP Used to detect wall motion abnormality Ultrasonographic Findings Intravascular ultrasound shows characteristic hypoechogenic filling defect within coronary lumen Echocardiographic Findings Echocardiogram Ancillary findings Regional wall motion abnormality of left ventricle Hypokinesis or akinesis Reduced ejection fraction Hyperkinesis of remaining left ventricular walls is possible Angiographic Findings Conventional Coronary angiography shows complete occlusion or stenosis of coronary artery Thrombus may be visible as filling defect or haziness if occlusion is not complete Fiberoptic angioscopy allows direct visualization of intraluminal thrombus, but it is not a clinically used modality Occasionally, a coronary artery side branch that is completely occluded at its origin may not be visible in invasive angiography, and diagnosis may be missed Imaging Recommendations Best imaging tool Invasive Coronary angiography Noninvasive Coronary CTA DIFFERENTIAL DIAGNOSIS Embolus While most coronary thrombotic lesions occur as a consequence of plaque rupture, embolism is a potential source of thrombus Endocarditis is a rare cause of coronary embolization Coronary Dissection Can result from percutaneous intervention (most frequent) Can result from engagement of diagnostic catheter into coronary artery Can occur spontaneously Cocaine Nonatherosclerotic cause of coronary artery thrombosis Possible consequences include dissection and plaque rupture with coronary thrombosis Suspect in young patients diagnosed with myocardial infarction Kawasaki Disease Long-term complications Coronary aneurysms Stenosis Thrombosis Vasculitis (Autoimmune) May lead to artery occlusion ± thrombus Most often part of a systemic disease Systemic lupus erythematous Rheumatoid arthritis 666

Diagnostic Imaging Cardiovascular Takayasu Arteritis Most commonly affects large vessels (aorta and great vessels) Can affect coronary circulation If so, coronary ostia are usually involved Aortic Dissection and Pulmonary Embolism Similar clinical presentation as acute coronary syndromes (acute chest pain) Similar ECG findings are possible Elevation of troponin values is possible PATHOLOGY General Features Etiology Rupture or, infrequently, erosion of coronary atherosclerotic plaque is the underlying mechanism in almost all cases of coronary thrombus Generally white thrombus (platelet rich) with secondary areas of red thrombus formation (red cells, thrombin, fibrin) P.8:44

Can occur simultaneously at multiple sites in coronary artery tree Staging, Grading, & Classification Coronary artery thrombosis may be Accompanied by myocardial necrosis Caused by complete occlusion of coronary artery or downstream embolization of thrombotic material Clinically, ST-elevation myocardial infarction (STEMI) or non-ST elevation myocardial infarction (NSTEMI) Accompanied by ischemia rather than myocardial necrosis Due to incomplete occlusion or collaterals Clinically, unstable angina Clinically silent Gross Pathologic & Surgical Features Vulnerable plaques: Coronary atherosclerotic plaques with high likelihood to rupture and cause acute coronary event Most frequently (but not exclusively) localized in proximal segments of coronary arteries Microscopic Features Histologic features predisposing plaque to rupture and cause acute coronary events Large plaque volume and positive remodeling Thin fibrous cap (< 65 µm) Lipid-rich core Large number of macrophages and monocytes Initiating event is fissure, usually in fibrous cap Exposes thrombogenic plaque content to blood stream, which in turn leads to thrombus formation CLINICAL ISSUES Presentation Most common signs/symptoms Acute chest pain Dyspnea Indigestion (especially with inferior wall infarction) Arrhythmias Other signs/symptoms Signs Pallor Diaphoresis Hypotension Clinical profile Risk factors Previously known coronary artery disease Older age Smoking 667

Diagnostic Imaging Cardiovascular Hyperlipidemia Diabetes Family history of premature coronary artery disease Male gender or postmenopausal female gender Hypertension Demographics Gender Mortality rate among men and women is equal over their lifetimes Ethnicity Coronary thrombosis with myocardial infarction has a higher incidence in blacks than in whites Natural History & Prognosis All forms of acute coronary syndrome have a high mortality if untreated Treatment Analgesia Antiplatelet and antithrombotic medical therapy Reperfusion Interventional Coronary angiography and percutaneous coronary intervention Medical Thrombolysis Long term Modification of cardiovascular risk factors Statins ACE inhibitors Antihypertensive medication DIAGNOSTIC CHECKLIST Consider In patients presenting with acute chest pain Coronary thrombus is most commonly the result of ruptured vulnerable nonstenotic plaque SELECTED REFERENCES 1. Go AS et al: Executive summary: heart disease and stroke statistics—2013 update: a report from the American Heart Association. Circulation. 127(1):143-52, 2013 2. Finkel JB et al: Rethinking cocaine-associated chest pain and acute coronary syndromes. Mayo Clin Proc. 86(12):1198-207, 2011 3. Finn AV et al: Concept of vulnerable/unstable plaque. Arterioscler Thromb Vasc Biol. 30(7):1282-92, 2010 4. Huang WC et al: Comparing culprit lesions in ST-segment elevation and non-ST-segment elevation acute coronary syndrome with 64-slice multidetector computed tomography. Eur J Radiol. 73(1):74-81, 2010 5. Tanaka A et al: Non-invasive assessment of plaque rupture by 64-slice multidetector computed tomography— comparison with intravascular ultrasound. Circ J. 72(8):1276-81, 2008 6. Motoyama S et al: Multislice computed tomographic characteristics of coronary lesions in acute coronary syndromes. J Am Coll Cardiol. 50(4):319-26, 2007 7. Hoffmann U et al: Noninvasive assessment of plaque morphology and composition in culprit and stable lesions in acute coronary syndrome and stable lesions in stable angina by multidetector computed tomography. J Am Coll Cardiol. 47(8):1655-62, 2006 8. Libby P et al: Pathophysiology of coronary artery disease. Circulation. 111(25):3481-8, 2005 9. Botnar RM et al: In vivo magnetic resonance imaging of coronary thrombosis using a fibrin-binding molecular magnetic resonance contrast agent. Circulation. 110(11):1463-6, 2004 10. Koiwaya Y et al: Angiographic features at ischemia- or infarct-related sites in patients with acute coronary syndrome: morphology changing in a relatively short time. J Cardiol. 38(4):187-96, 2001 11. Goldstein JA et al: Multiple complex coronary plaques in patients with acute myocardial infarction. N Engl J Med. 343(13):915-22, 2000 P.8:45

Image Gallery

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(Left) Coronary CT angiography in a patient with a high-grade proximal stenosis of the right coronary artery (RCA) due to plaque rupture shows positive remodeling and large amounts of low-density material (plaque or thrombus) .A cross section displays a ring-like contrast enhancement . Note stable stenosis in the mid RCA . (Right) Invasive coronary angiography in the same patient shows a proximal acute high-grade stenosis and a 2nd stenosis in the mid RCA .

(Left) Contrast-enhanced coronary CT angiography in a different patient demonstrates an acute thrombotic occlusion of the ostial left anterior descending coronary artery leading to an ST-segment elevation myocardial infarction. (Right) Invasive coronary angiography in the same patient shows the ostial occlusion of the left anterior descending coronary artery . Only the left main and left circumflex coronary arteries are open.

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(Left) Contrast-enhanced coronary CT angiography shows a large thrombus extending from the left main coronary artery to the left anterior descending coronary artery. The cross-section inset reveals the typical pattern of a central filling defect surrounded by contrast . (Right) Coronary thrombosis can lead to total vessel occlusion as seen here in invasive coronary angiography showing an occlusion of the distal right coronary artery . P.8:46

(Left) Coronary thrombosis can lead to a total vessel occlusion as seen here in invasive coronary angiography showing an occlusion of the distal right coronary artery . (Right) Intracoronary thrombus aspiration in the same patient produces small segments of thrombotic material that have led to vessel occlusion .

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(Left) Invasive coronary angiography in a patient with an acute coronary syndrome shows a single large thrombus leading to a filling defect in the right coronary artery . (Right) Intracoronary thrombus is frequently multifocal as a consequence of multiple plaque ruptures or embolization of a thrombotic material that has formed more proximally. Here, 2 areas of high-grade luminal obstruction with the typical hazy appearance of fresh thrombus are present in the right coronary artery .

(Left) Coronary CT angiography in a patient with an acute coronary syndrome shows, very proximally, an atherosclerotic plaque that does not lead to significant lumen stenosis and is followed by 3 severe stenoses . The 2nd of these 3 stenoses displays typical signs of acute rupture/thrombosis (i.e., positive remodeling, low density, and ring-like enhancement). (Right) Invasive coronary angiography shows no stenosis at the proximal plaque , followed by 3 high-grade stenoses . P.8:47

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(Left) Contrast-enhanced coronary CTA from a patient with non-ST elevation myocardial infarction shows an acute thrombotic obstruction with positive remodeling in the mid left circumflex coronary artery. (Right) Coronary CTA (4-chamber view) in the same patient demonstrates a myocardial perfusion defect in the posterolateral wall, consistent with an acute myocardial infarction in the left circumflex coronary artery territory. Note a beam hardening artifact in the apical region .

(Left) Invasive coronary angiography (left anterior oblique caudal projection; same patient) shows occlusion of the left circumflex coronary artery. Note faint filling of distal vessel segments via collaterals . (Right) Invasive coronary angiography in the same patient after reopening of the occluded left circumflex coronary artery by percutaneous coronary intervention shows contrast filling the previously occluded left circumflex coronary artery.

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(Left) Not every acute lesion displays the typical CT characteristics of thrombosis. Here, an acute ST-elevation myocardial infarction occlusion of the left anterior descending coronary artery is present , but plaque or thrombus is not distinguishable. Note diagonal branch . (Right) Invasive coronary angiography in the same patient shows an occluded left anterior descending coronary artery before (left) and after (right) reopening. Note diagonal branch .

Coronary Artery Stenosis Key Facts Terminology Fixed obstructive coronary artery disease that typically causes symptoms during exercise Often termed “stable coronary artery disease” Imaging Testing for coronary artery stenosis Direct visualization of coronary arteries (invasive angiography, coronary CT angiography) Testing for ischemia (MR, nuclear medicine, stress echocardiography) Coronary artery stenoses are traditionally assumed to be hemodynamically relevant when > 70% diameter stenosis is present (50% if left main coronary artery) However, correlation between anatomic stenosis severity and hemodynamic relevance is poor Choice of testing modality is influenced by patient characteristics and pretest probability of coronary artery disease Most guidelines mandate testing for ischemia before visualization of coronary arteries Top Differential Diagnoses Other cardiac disease Noncardiac source of symptoms Clinical Issues Common symptoms: Shortness of breath or chest, shoulder, neck, or jaw pain reproducible with exertion Treatment: Prevention of coronary artery events and symptom relief Prevention is based on medication with aspirin, statins, ACE inhibitors, and control of diabetes and hypertension Revascularization only if > ˜ 10% of myocardium is ischemic, if left main coronary artery has relevant stenosis, or if > 1 coronary artery has hemodynamically relevant stenosis

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(Left) Invasive coronary angiography of the left coronary system (left main injection) shows the left anterior descending coronary artery with a high-grade stenosis and the left circumflex coronary artery . (Right) Coronary CT angiography maximum-intensity projection in the same patient shows a high-grade stenosis of the left anterior descending coronary artery caused by a noncalcified atherosclerotic plaque.

(Left) Aside from anatomic imaging, coronary artery stenoses can be detected on imaging of ischemia. Seen here is an MR adenosine stress myocardial perfusion study with a subendocardial area of hypoperfusion in the inferior and posterolateral left ventricular walls , indicating a high-grade stenosis of the right coronary artery. (Right) Stress myocardial perfusion SPECT shows a perfusion defect in the anterior wall , indicating a hemodynamically relevant stenosis of the left anterior descending coronary artery. P.8:49

TERMINOLOGY Definitions Fixed obstructive coronary artery disease Often termed “stable coronary artery disease” IMAGING General Features Traditionally assumed to be hemodynamically relevant when > 70% diameter stenosis is present, except in left main coronary artery stenosis, where 50% diameter stenosis is considered relevant Exception: 50% diameter stenosis is considered relevant for left main coronary artery Correlation of anatomic stenosis severity and hemodynamic relevance is poor Based on clinical and outcome data, fractional flow reserve (FFR) has replaced angiography as reference standard to establish significance (i.e., hemodynamic relevance) of coronary artery stenosis 674

Diagnostic Imaging Cardiovascular FFR < 0.75-0.80 is considered indication for revascularization Radiographic Findings Radiography Coronary artery calcification may be visible in chest radiography and fluoroscopy, indicating coronary atherosclerosis CT Findings NECT Coronary calcium Definitive for presence of coronary artery atherosclerosis but not for presence of hemodynamically relevant stenosis Associated with risk for future cardiovascular events in asymptomatic individuals and can be used for risk stratification CTA 64-detector row CT is currently considered minimum standard for coronary CT angiography Heart rhythm should be regular for coronary CTA, and image quality improves substantially when heart rate is lowered to < 60 beats/min Retrospectively ECG-gated helical acquisition permits reconstruction of image data sets at arbitrary time points in cardiac cycle Provides flexibility to identify optimal cardiac phase without motion artifact Associated with high radiation exposure Prospectively ECG-triggered axial acquisition substantially reduces radiation exposure but requires low and regular heart rate Contrast injection should be performed at high flow rates (5-7 mL/s) Image interpretation may be impaired by motion artifact, large calcified plaques, and noise Sensitivity for coronary artery stenosis detection is > 90%; specificity may be lower, especially in cases of impaired image quality MR Findings Left ventricular function at rest can be normal even in severe coronary artery disease Late gadolinium enhancement (LGE) using gradient-echo inversion-recovery sequences Scar tissue appears as bright, or hyperenhanced, myocardium If typically distributed in transmural or subendocardial pattern and in a vascular territory, indicative of past myocardial infarction Left ventricular function under dobutamine infusion High accuracy for identification of hemodynamically relevant stenosis Myocardial 1st-pass perfusion at rest and under adenosine infusion High accuracy for identification of hemodynamically relevant stenosis Echocardiographic Findings Echocardiogram Baseline study can be entirely normal; wall motion abnormalities indicate past myocardial infarction Stress echocardiography is most commonly performed with physical exercise or graded dobutamine stress Angiographic Findings Invasive coronary angiography Stenosis degree is usually determined by visual estimation May be combined with intravascular ultrasound (IVUS) for more definite assessment of plaque/stenosis morphology May be combined with FFR measurement to assess hemodynamic relevance FFR requires measurement of blood pressure distal to lesion with special wire Usually performed during continuous intravenous adenosine injection May be combined with percutaneous coronary intervention in same session Nuclear Medicine Findings PET Excellent for assessing perfusion, ischemia, and viability Rb-82 (most frequently) or 13NH3 is used for assessment of perfusion at rest and stress 18F FDG is used for assessment of glucose utilization (viability) Limitations include cost and limited availability SPECT myocardial perfusion Very frequently used to identify myocardial ischemia TI-201 (high radiation exposure) or Tc-99m (e.g., 99mTc sestamibi) is used as perfusion tracer 675

Diagnostic Imaging Cardiovascular Comparison of physical exercise or pharmacologic stress (high-flow state) with rest (low-flow state) Adenosine is the most frequently utilized pharmacologic agent Reduced tracer uptake at stress (as compared with rest), wall thinning, left ventricular dilation in stress image, or increased lung uptake (slow transit time) indicates ischemia “Fixed defect” (stress and rest) implies myocardial scar Care is required in interpretation Apical thinning, breast attenuation artifacts, diaphragm attenuation artifacts, motion artifacts, bundle branch block, and inadequate exercise P.8:50

Imaging Recommendations Direct visualization of coronary arteries: Invasive angiography, coronary CT angiography Testing for ischemia: MR, nuclear medicine, stress echocardiography Choice of testing modality is influenced by patient characteristics and pretest probability of coronary artery disease Most guidelines mandate testing for ischemia before visualization of coronary arteries Most definitive test is invasive coronary angiography combined with IVUS and FFR DIFFERENTIAL DIAGNOSIS Other Cardiac Disease Aortic stenosis, hypertrophic cardiomyopathy, hypertension, acute myocarditis, pericarditis, coronary spasm, mitral valve prolapse, syndrome X Noncardiac Source of Symptoms Vascular disease: Aortic dissection or pulmonary embolism Gastrointestinal disease: Hiatus hernia, acid reflux, cholecystitis, or peptic ulcer Musculoskeletal disease: Of chest wall or shoulders PATHOLOGY General Features Etiology Most common cause of stenosis: Atherosclerotic plaque Genetics Strong genetic influence on atherosclerosis Atherosclerosis Most important risk factors include smoking, hyperlipidemia, hypertension, diabetes, and familial history of premature coronary artery disease Coronary atherosclerotic plaque burden can be extensive without necessarily causing coronary artery stenosis Plaque erosion/rupture, platelet aggregation, and thrombosis lead to stenosis progression and acute coronary syndromes (myocardial infarction and unstable angina) Nonatherosclerotic causes for coronary artery stenosis or occlusion Vasculitis, Takayasu disease, Kawasaki disease Coronary anomalies can lead to coronary artery narrowing due to stretch or external compression CLINICAL ISSUES Presentation Most common signs/symptoms Chest, shoulder, neck, or jaw pain or shortness of breath that is reproducible with exertion Clinical profile Risk profiling is critical part of evaluating patients suspected of significant coronary artery stenosis Demographics Age Likelihood of coronary artery disease ↑ with age Gender M>F Ethnicity African Americans and Asian Indians have higher risk of coronary artery disease and higher cardiovascular mortality Epidemiology Leading cause of mortality and morbidity in developed world Treatment 676

Diagnostic Imaging Cardiovascular Prevention of coronary artery events Based on medication with aspirin, statins, ACE inhibitors, and control of diabetes and hypertension Symptom relief Medication Nitrates, β-blockers, and calcium antagonists Revascularization Prognostically relevant only if > ˜ 10% of myocardium is ischemic, if left main coronary artery has relevant stenosis, or if > 1 coronary artery (including proximal left main coronary artery) has hemodynamically relevant stenosis Options include coronary artery bypass surgery and percutaneous coronary intervention DIAGNOSTIC CHECKLIST Consider Not every stenosis necessarily causes ischemia Plaque burden can be extensive without relevant stenosis Testing for coronary artery stenosis can be based either on direct visualization of coronary arteries (invasive angiography, coronary CT angiography) or on testing for ischemia (MR, nuclear medicine, stress echocardiography) Most common differential diagnoses for stable coronary artery disease: Musculoskeletal pain and gastroesophageal reflux SELECTED REFERENCES 1. Coelho-Filho OR et al: MR myocardial perfusion imaging. Radiology. 266(3):701-15, 2013 2. Pijls NH et al: Functional measurement of coronary stenosis. J Am Coll Cardiol. 59(12):1045-57, 2012 3. Achenbach S: Current clinical applications of cardiac computed tomography. J Cardiovasc Transl Res. 4(4):449-58, 2011 4. Beller GA et al: SPECT imaging for detecting coronary artery disease and determining prognosis by noninvasive assessment of myocardial perfusion and myocardial viability. J Cardiovasc Transl Res. 4(4):416-24, 2011 5. Bengel FM et al: Cardiac positron emission tomography. J Am Coll Cardiol. 54(1):1-15, 2009 6. Fraker TD Jr et al: 2007 chronic angina focused update of the ACC/AHA 2002 guidelines for the management of patients with chronic stable angina: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines Writing Group to develop the focused update of the 2002 guidelines for the management of patients with chronic stable angina. J Am Coll Cardiol. 50(23):2264-74, 2007. Erratum in: J Am Coll Cardiol. 50(23):e1, 2007 P.8:51

Image Gallery

(Left) Contrast-enhanced coronary CT angiography, oblique maximum-intensity projection, shows a high-grade stenosis in the mid right coronary artery. In addition, numerous calcified plaques are found along the entire course of the vessel. (Right) Invasive coronary angiography, right anterior oblique projection, shows a high-grade stenosis in the mid segment of the right coronary artery.

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(Left) Contrast-enhanced coronary CT angiography, maximum-intensity projection in axial orientation, shows a stenosis of moderate degree in the left anterior descending coronary artery, at the bifurcation to the diagonal branch. (Right) Invasive coronary angiography in anteroposterior cranial projection in the same patient shows a stenosis of moderate degree in the left anterior descending coronary artery. The stenosis involves the origin of the diagonal branch .

(Left) Contrast-enhanced coronary CT angiography, maximum intensity projection in axial orientation, shows a chronic total occlusion of the left anterior descending coronary artery . The vessel is occluded between the 1st and 2nd diagonal branches. (Right) Invasive coronary angiography (same patient) shows that the left anterior descending coronary artery is occluded immediately distal to the origin of the large 1st diagonal branch . The left circumflex coronary artery is chronically occluded . P.8:52

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(Left) The anatomic severity and functional relevance of coronary artery stenosis do not necessarily correlate closely. Here, invasive angiography shows only mild mid left anterior descending coronary artery stenoses , but the corresponding invasive fractional flow reserve (FFR) using adenosine infusion has a value of 0.66, indicating hemodynamic significance. (Right) Here, an anatomically high-grade stenosis in the left anterior descending artery has an FFR = 0.95, indicating lack of hemodynamic relevance.

(Left) Contrast-enhanced coronary CT angiography shows a very short, noncalcified, high-grade stenosis of the left circumflex coronary artery. Note that the coronary lumen within the high-grade stenosis seems completely interrupted; the residual lumen is below the spatial resolution of coronary CT angiography. (Right) Invasive coronary angiography in the same patient shows a short, high-grade stenosis of the left circumflex coronary artery.

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(Left) The degree of stenosis often appears more severe in coronary CT angiography than in invasive angiography. In this example, coronary CT angiography shows a stenosis of the mid left anterior descending coronary artery that appears to be moderate to high grade; the large amount of plaque and positive remodeling contribute to this visual impression. (Right) Invasive coronary angiography in the same patient shows that the degree of luminal stenosis is moderate . P.8:53

(Left) Contrast-enhanced coronary CT angiography, oblique maximum-intensity projection of the right coronary artery, shows a short interruption of the coronary artery lumen. Such lesions can either be high-grade stenoses or complete occlusions of a coronary artery. (Right) Invasive coronary angiography in right anterior oblique orientation in the same patient shows a complete occlusion of the right coronary artery.

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(Left) Contrast-enhanced coronary CT angiography, curved multiplanar reconstruction of the right coronary artery, shows a proximal high-grade stenosis followed by a long occlusion of the vessel. (Right) Invasive coronary angiography in right anterior oblique orientation in the same patient demonstrates a short high-grade proximal stenosis followed by a total occlusion .

(Left) At the ostium of the left anterior descending artery, motion artifact in combination with coronary calcium causes the false-positive impression of a high-grade stenosis . Invasive angiography (inset) shows absence of stenosis . (Right) Slight motion artifact and noise impair image quality. Proximally, a partially calcified plaque is not associated with a relevant luminal stenosis . A subsequent short interruption of the lumen corresponds to a high-grade left circumflex stenosis (inset).

Ischemia RCA Stenosis Key Facts Terminology Obstructive coronary disease in right coronary artery Imaging Coronary CTA (64 slices) has high sensitivity (98%), specificity (88%), and negative predictive value (95-100%) for detection of hemodynamically significant stenosis Late enhancement can demonstrate presence, location, and size of infarction 1st pass perfusion may show perfusion defect in inferior left ventricular wall MR Late enhancement can demonstrate presence, location, and size of infarction in right ventricular wall or inferior left ventricular wall 681

Diagnostic Imaging Cardiovascular 1st-pass perfusion may show perfusion defect in inferior left ventricular wall Intravascular ultrasound is clinical gold standard allowing visualization of virtual histology Dobutamine stress echo sensitivity and specificity: 80-85% Invasive coronary angiography Functional obstruction indices across lesion are assessed by fractional flow reserve Best noninvasive tests: Coronary CTA for anatomical depiction; stress MR for functional significance Clinical Issues Typical anginal symptoms Bradyarrhythmias if atrioventricular or sinoatrial node is involved Therapeutic goal: Relief of symptoms and prevention of further ischemia Drug-eluting stent is preferred over bare-metal stent if dual antiplatelet therapy is not contraindicated CABG is typically used if other vessel disease

(Left) Coronary CTA shows a diffusely diseased right coronary artery (RCA) with multiple high-grade luminal stenoses in multiple coronary segments. Note the positive remodeling of several of the lesions. (Right) Corresponding short-axis 5 mm multiplanar reformat image shows a transmural hypoattenuation defect in the left ventricular basal inferior myocardial segment, consistent with RCA ischemia.

(Left) Invasive coronary angiogram in the same patient confirms multiple high-grade stenoses . Note that stenosis severity is accurately assessed on invasive angiography, but positive plaque remodeling is shown only on CTA. (Right) Corresponding adenosine stress perfusion cardiovascular MR shows a left ventricular basal inferior segment inducible perfusion defect indicating RCA ischemia. Note the transmural nature of true perfusion defect (dark-rim artifact remains subendocardial). P.8:55

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TERMINOLOGY Definitions Hemodynamically stenotic coronary disease in right coronary artery (RCA) IMAGING General Features Location RCA originates from right sinus, slightly more caudal than left main coronary artery, and supplies right ventricle (RV) or inferior aspect of interventricular septum Morphology RCA traverses right atrioventricular (AV) groove Conus branch supplies RV outflow tract, is 1st branch of RCA (50%), or originates from right sinus ostium In 60%, RCA atrial branches supply sinoatrial (SA) node, and in 40% left circumflex (LCX) Dominance is defined as coronary artery supplying posterior descending artery (PDA) 70% of patients are RCA dominant PDA courses along inferior interventricular groove, providing septal perforators, a feature that may aid in its identification and differentiation from posterolateral segment of RCA (or LCX), which gives off branches to posterior/inferior left ventricle (LV) In > 90%, artery to AV node originates from posterior left ventricular branch of RCA at crux Radiographic Findings Chest radiography Usually normal findings in absence of myocardial infarction Fluoroscopic Findings Coronary angiography can detect and quantify RCA stenosis CT Findings CTA Coronary CTA (64 slices) has high sensitivity (98%), specificity (88%), and negative predictive value (95100%) for detection of hemodynamically significant stenosis Genu of RCA may move rapidly during ventricular systole Systolic reconstruction phase (30%) may be best for RCA analysis Obstructive RCA lesions may cause arrhythmias (block SA/AV nodal branch) May affect RV function Regional wall motion abnormalities in inferior myocardial segments CT perfusion 1st-pass perfusion information can be derived from same data set used for CTA Inferior wall myocardial hypoperfusion defects may be seen MR Findings Viability Late enhancement MR or CT can demonstrate presence, location, and size of infarction MR uses gradient-echo double inversion-recovery sequence 7-10 minutes after bolus of 0.1-0.2 mmol/kg gadolinium Vary inversion time (TI) to maximize nulling of normal myocardium Nonviable myocardium appears high signal in inferior LV and RV walls Healthy viable myocardium appears black Perfusion 1st-pass perfusion (stress followed by rest) Hybrid gradient-echo-planar sequence acquired during rapid bolus of 0.1 mmol/kg gadolinium Short-axis stack (typically 3-5 slices) 1st-pass stress perfusion defect in inferior LV wall indicates ischemia Regional wall motion MR is gold standard for chamber volumetrics Standardized 17-segment American Heart Association model is utilized Regional wall hypokinesis/akinesis/dyskinesis in inferior/inferoseptal LV wall Coronary arteries Free-breathing 3D acquisition of coronary artery in real time Sensitivity of 72% and specificity of 87% for significant coronary artery stenosis Ultrasonographic Findings Echocardiogram 683

Diagnostic Imaging Cardiovascular Dobutamine stress echo Stress study performed with dobutamine infusion Sensitivity and specificity: 80-85% Evaluate lack of increase in systolic function or appearance of hypokinetic, akinetic, or dyskinetic segments in inferior LV wall Intravascular ultrasound (IVUS) Allows visualization of virtual histology Avoids stent underexpansion and leads to less restenosis May reduce late stent thrombosis and major adverse cardiac events in drug-eluting stent implantation Angiographic Findings Invasive coronary angiography Hemodynamically significant stenosis generally if luminal narrowing of RCA is ≥ 70% Can evaluate collateral supply to ischemic territory Limitations Severity of stenosis is estimated visually, but interobserver variability is wide Diffuse disease may lead to underestimation of stenoses Does not give functional obstruction indices across lesion Left ventriculography findings Reduced wall motion and thickening in inferoposterior territory Fractional flow reserve (FFR) Expressed as ratio of coronary pressure distal to stenosis to simultaneous aortic pressure measurement during maximal hyperemia FFR < 0.75 is considered functionally significant Optical coherence tomography P.8:56

Higher accuracy than IVUS and coronary CTA in discriminating early from advanced lesions Nuclear Medicine Findings PET Gold standard for myocardial viability assessment Allows qualitative and quantitative assessment of regional myocardial perfusion Shows inferior LV wall ischemic defects or nonviable myocardium Other Modality Findings SPECT Thallium or technetium imaging to detect reversible perfusion defects and myocardial wall thinning Must differentiate inferior myocardium from diaphragm and liver Exercise reduces splanchnic blood flow, improving contrast Including analysis of RV on thallium-201 stress scintigrams improves detection of proximal RCA lesions Imaging Recommendations Best imaging tool Best noninvasive tests: Coronary CTA for anatomical depiction and stress MR for functional significance Best invasive test: Coronary angiography with FFR DIFFERENTIAL DIAGNOSIS Cardiac Disease Acute myocarditis, coronary spasm Noncardiac Disease Musculoskeletal diseases of chest wall or shoulders Gastrointestinal diseases: Hiatus hernia, acid reflux, peptic ulcer disease, cholecystitis PATHOLOGY General Features Vascular occlusion with inferior segment necrosis Gross Pathologic & Surgical Features Myocardial thinning of inferior segment in chronic RCA myocardial infarction (MI) Microscopic Features MI initiating event is a fissure in arterial plaque cap Results in exposure of subendothelial matrix elements Platelet activation and thrombus formation ensues CLINICAL ISSUES 684

Diagnostic Imaging Cardiovascular Presentation Most common signs/symptoms Typical anginal symptoms (e.g., central crushing chest pain) Nausea, vomiting, diaphoresis Hypotension if RV is involved Other signs/symptoms Hiccups Bradyarrhythmias if AV or SA node is involved ECG findings ST segment changes in inferior ECG leads Clinical profile Risk factors: Smoking, cholesterol elevation, diabetes, hypertension, family history Treatment Goal: Relief of symptoms and prevention of further ischemia Medical Angina managed with vasodilators and inotropic/chronotropic control P2Y12 receptor antagonist and dual antiplatelet therapy (DAPT) after stent placement Secondary prevention Lifestyle modifications, including daily physical activity, weight goals, blood pressure control, lipid control, diabetes control, and smoking cessation β-blockers in patients with LV ejection fraction (EF) < 40% with heart failure or prior MI Continue for 3 years in patients with normal LVEF with MI or acute coronary syndrome ACE inhibitors/angiotensin receptor blockers (ARBs) in patients with LVEF < 40%, hypertension, diabetes, or chronic kidney disease Statin dose to reduce low-density lipoprotein cholesterol (LDL-C) < 100 mg/dL Interventional Drug-eluting stent is preferred over bare-metal stent if DAPT is not contraindicated Technically difficult in “shepherd's crook” RCA (˜ 5%) Surgical Coronary artery bypass graft (CABG) if other vessel diseases coexist SELECTED REFERENCES 1. Maurovich-Horvat P et al: Differentiation of early from advanced coronary atherosclerotic lesions: systematic comparison of CT, intravascular US, and optical frequency domain imaging with histopathologic examination in ex vivo human hearts. Radiology. 265(2):393-401, 2012 2. Pijls NH et al: Functional measurement of coronary stenosis. J Am Coll Cardiol. 59(12):1045-57, 2012 3. Sbruzzi G et al: Intracoronary ultrasound-guided stenting improves outcomes: a meta-analysis of randomized trials. Arq Bras Cardiol. 98(1):35-44, 2012. Review. English, Portuguese, Spanish. Erratum in: Arq Bras Cardiol. 98(1):1, 2012 4. van de Hoef TP et al: Diagnostic accuracy of combined intracoronary pressure and flow velocity information during baseline conditions: adenosine-free assessment of functional coronary lesion severity. Circ Cardiovasc Interv. 5(4):508-14, 2012 5. Fukui T et al: Assessment of coronary flow velocity reserve by transthoracic Doppler echocardiography before and after coronary artery bypass grafting. Am J Cardiol. 107(9):1324-8, 2011 6. Smith SC Jr et al: AHA/ACCF secondary prevention and risk reduction therapy for patients with coronary and other atherosclerotic vascular disease: 2011 update. Circulation. 124(22):2458-73, 2011 7. Young PM et al: Cardiac imaging: Part 2, normal, variant, and anomalous configurations of the coronary vasculature. AJR Am J Roentgenol. 197(4):816-26, 2011 8. Kumar A et al: Contrast-enhanced cardiovascular magnetic resonance imaging of right ventricular infarction. J Am Coll Cardiol. 48(10):1969-76, 2006 9. Somsen GA et al: Right ventricular ischaemia due to right coronary artery stenosis. Heart. 90(6):696, 2004 P.8:57

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(Left) Coronal oblique coronary CTA (C view) shows an ostial high-grade stenosis of the right coronary artery and scattered nonobstructive plaque in the mid right coronary artery. (Right) Corresponding invasive coronary angiogram confirms a high-grade ostial stenosis of the right coronary artery . Occasionally, the catheter may be placed past an ostial stenosis (not in this example), in which case an ostial lesion may not be apparent.

(Left) An oblique 5 mm maximum-intensity projection (MIP) image along the base of the heart can illustrate the posterior descending artery (PDA) and posterior left ventricular (PLV) artery optimally. This case shows an obstructive lesion in the PLV branch. Note the proximal middle cardiac vein . (Right) Corresponding invasive angiogram confirms an obstructive coronary stenosis in the right PLV branch. Note the unobstructed right PDA and mid RCA .

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(Left) Coronal oblique coronary CTA shows a diffusely diseased RCA with a high-grade long-segment stenosis in its mid portion , which eventually appears to occlude . However, the distal segment seems to reconstitute . (Right) Invasive coronary angiogram of the left main coronary artery (same patient) shows that the reconstituted distal segment of RCA is due to distal RCA filling through numerous collaterals from the left anterior descending and left circumflex coronary arteries.

Left Main Coronary Stenosis Key Facts Terminology ≥ 50% luminal narrowing of left main (LM) coronary artery Imaging Coronary CTA (64 slices) has high sensitivity (98%), specificity (88%), and negative predictive value (95-100%) for detection of hemodynamically significant stenosis Close to 100% for LM stenosis Finding of CAD by 64-slice CT has incremental prognostic value over left ventricular ejection fraction and clinical variables Coronary CTA allows considerable plaque characterization and shows good agreement with intravascular ultrasound (IVUS) Use of IVUS avoids stent underexpansion and results in less restenosis Invasive coronary angiography provides information about lumen diameter but yields little insight into lesion and plaque characteristics Top Differential Diagnoses Coronary artery spasm Coronary dissection Coronary anomaly Clinical Issues Unstable angina is most common symptom Currently, CABG is recommended for patients with significant LM stenosis Percutaneous coronary intervention can be alternative therapy in selected cases Current guidelines support long-term aspirin administration and ≥ 6-12-month dual antiplatelet therapy in patients receiving drug-eluting stent

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(Left) Oblique coronary CTA shows a tight left main (LM) coronary artery lesion with significant stenosis (> 50%) caused by noncalcified atherosclerotic plaque. Note that there is noncalcified plaque causing only mild left anterior descending (LAD) coronary artery stenosis in the proximal segment . (Right) Corresponding oblique invasive coronary angiogram confirms a significant stenosis of the LM . There was immediate dampening on pressure tracing. The patient underwent bypass grafting.

(Left) Axial coronary CT in a 56-year-old man with chest pain on exertion shows LM coronary stenosis . Lumen stenosis is ˜ 90%, secondary to a noncalcified plaque. Note multiple moderate calcified plaques in the LAD and 1 diagonal branch . (Right) Corresponding coronary angiogram shows severe left main stenosis . There was immediate pressure dampening on catheter insertion into the LM ostium. (Courtesy R. Murphy, MD.) P.8:59

TERMINOLOGY Definitions ≥ 50% luminal narrowing of left main (LM) coronary artery LM: Proximal segment of left coronary artery arising from left aortic sinus, just below sinotubular junction, to its bifurcation into left anterior descending and left circumflex arteries LM supplies 75% of left ventricular mass in right-dominant type or balanced type and 100% in leftdominant type IMAGING General Features Best diagnostic clue Stenosis ≥ 50% of LM identified by multiple imaging modalities Location 688

Diagnostic Imaging Cardiovascular Most common site: Mid or distal portion of LM At LM bifurcation, atherosclerosis is accelerated primarily in area of high shear stress in lateral wall Size Degree of stenosis is related to survival 50-70% LM stenosis: 3-year survival of 66% > 70% LM stenosis: 3-year survival of 41% Radiographic Findings Radiography Chest radiography findings Usually normal in absence of heart failure CT Findings CTA Coronary CTA (64 slices) has high sensitivity (98%), specificity (88%), and negative predictive value (95100%) for detection of hemodynamically significant stenosis Essentially 100% sensitivity and specificity for LM stenosis in absence of artifact Finding of CAD by CT has incremental prognostic value over left ventricular ejection fraction and clinical variables Coronary CTA allows considerable plaque characterization and has shown good agreement with intravascular ultrasound (IVUS) MR Findings Whole heart MR Useful, noninvasive alternative in patients with contraindications to CT Images entire coronary system in 1 acquisition Steady-state free precession sequence covers entire heart Does not have spatial resolution of cardiac CTA Prospective navigator gating and volume tracking Ultrasonographic Findings Echocardiogram Reduced wall motion may be apparent Coronary flow velocity reserve (CFR) Short-axis parasternal views to visualize LM Pulsed Doppler to determine velocity at rest and maximal hyperemia CFR < 2 is considered functionally significant IVUS Permits detailed, high-quality, cross-sectional imaging of LM in vivo Many patients with angiographically normal LM have abnormal IVUS studies Use of IVUS avoids stent underexpansion and results in less restenosis Angiographic Findings Invasive coronary angiography Considered clinical gold standard Provides information about lumen diameter but yields less insight into lesion and plaque characteristics Diffuse disease may be difficult to quantify Ostial lesions may be missed if catheter is pushed past lesion May be dampening, with no reflux of contrast back into aorta High index of suspicion at angiography if ostial lesion is suspected Sinus injection first is mandatory Careful advancement of catheter Limited number of shots Anteroposterior projection is most useful Glagov effect (vessel dilates in response to plaque formation) Considerable interobserver variability for LM stenosis Fractional flow reserve (FFR) may play adjunctive role in determining significant stenosis at LM FFR: Ratio of maximal blood flow achievable in stenotic vessel to normal maximal flow in same vessel FFR < 0.75 is reliable indicator of significant stenosis producing inducible ischemia Optical coherence tomography (OCT) Provides superior definition of thin fibrous caps compared with IVUS Nuclear Medicine Findings PET High sensitivity for detection of ischemic territory 689

Diagnostic Imaging Cardiovascular Nuclear cardiology findings Thallium or technetium imaging to detect flow-limited zones Left ventricular dilatation may appear during stress LM stenosis appears as reduced uptake in septum and anterior and lateral walls ˜ 60% of patients with LM stenosis have multiple thallium defects Imaging Recommendations Best imaging tool Evolving topic: Coronary angiography is clinical gold standard Coronary CTA is rapidly evolving, noninvasive alternative IVUS/OCT if available DIFFERENTIAL DIAGNOSIS LM Mimics Coronary artery spasm Coronary anomaly Coronary dissection For coronary CTA, beware of artifact slab lines P.8:60

PATHOLOGY General Features Etiology Poorly understood Principal cause: Atherosclerosis Nonatherosclerotic considerations Syphilis Giant cell arteritis Takayasu arteritis Trauma (iatrogenic) Anomalous takeoff CLINICAL ISSUES Presentation Most common signs/symptoms Spectrum of symptoms varies from asymptomatic to sudden death Unstable angina is most common symptom 7% of patients with acute myocardial infarction Other signs/symptoms ECG reveals ST elevation in aVR ≥ ST segment in lead V1 Clinical profile Smoking, cholesterol elevation, diabetes, hypertension, positive family history Natural History & Prognosis 80% of patients have concomitant lesions in other vessels Isolated LM stenosis is rare (< 0.5-1% of patients) Significant LM narrowing puts patient at high risk of infarction or death If no collateral flow, 75% blood supply to left ventricle is compromised Mortality for nonrevascularized LM disease: 37% at 3 years Treatment Medical Current guidelines support long-term aspirin administration and ≥ 6-12-month dual antiplatelet therapy in patients receiving drug-eluting stent Interventional Intervention is preferred over medical therapy owing to mortality benefit Follows 2011 American Heart Association guidelines for percutaneous coronary intervention (PCI) PCI is alternative to CABG in selected cases Stable patients with significant unprotected left main CAD Patients with anatomic conditions associated with low risk of PCI procedural complications (ostial or trunk left main CAD) Patients with significantly increased risk of adverse surgical outcomes (e.g., STSpredicted risk of operative mortality ≥ 5%) 690

Diagnostic Imaging Cardiovascular PCI in patients with unstable angina/non-ST-segment elevation myocardial infarction when unprotected LM is culprit lesion and patient is not candidate for CABG PCI for improving of survival is reasonable in patients with acute ST-segment elevation myocardial infarction when Unprotected LM is culprit lesion Distal coronary flow is less than thrombolysis in myocardial infarction grade 3 PCI can be performed more rapidly and safely than CABG Rotational atherectomy for fibrotic or heavily calcified lesions that cannot be crossed by balloon catheter or adequately dilated prestent Surgical Currently, CABG is recommended as treatment of choice for patients with significant LM stenosis DIAGNOSTIC CHECKLIST Consider In any patient presenting with crescendo angina Image Interpretation Pearls LM stenosis ≥ 50% luminal narrowing Most common site of stenosis: Mid or distal portion of LM 80% of patients have concomitant lesions in other vessels SELECTED REFERENCES 1. Fajadet J et al: Current management of left main coronary artery disease. Eur Heart J. 33(1):36-50b, 2012 2. Levine GN et al: 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention: executive summary: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions. Catheter Cardiovasc Interv. 79(3):45395, 2012 3. Chow BJ et al: Incremental prognostic value of cardiac computed tomography in coronary artery disease using CONFIRM: COroNary computed tomography angiography evaluation for clinical outcomes: an InteRnational Multicenter registry. Circ Cardiovasc Imaging. 4(5):463-72, 2011 4. Garg S et al: Clinical and angiographic risk assessment in patients with left main stem lesions. JACC Cardiovasc Interv. 3(9):891-901, 2010 5. Park SJ et al: Percutaneous coronary intervention for unprotected left main coronary artery stenosis. World J Cardiol. 2(4):78-88, 2010 6. Sheiban I et al: Long-term clinical and angiographic outcomes of treatment of unprotected left main coronary artery stenosis with sirolimus-eluting stents. Am J Cardiol. 100(3):431-5, 2007 7. Suh WM et al: Utility of cardiac MRI in guiding revascularization therapy in unprotected left main stenosis: a case report. Cardiovasc Revasc Med. 8(3):209-12, 2007 8. Caussin C et al: Comparison of coronary minimal lumen area quantification by sixty-four-slice computed tomography versus intravascular ultrasound for intermediate stenosis. Am J Cardiol. 98(7):871-6, 2006 9. Jönsson A et al: Left main coronary artery stenosis no longer a risk factor for early and late death after coronary artery bypass surgery—an experience covering three decades. Eur J Cardiothorac Surg. 30(2):311-7, 2006 P.8:61

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(Left) Coronary CTA shows a large, noncalcified plaque extending from the distal LM into the proximal segment LAD (widow-maker lesion). Note positive remodeling , a plaque feature associated with increased risk of future plaque rupture. (Right) Corresponding invasive angiogram confirms high-grade stenosis . The invasive angiogram underestimated length of the plaque into LM. Patient was a 33-year-old cyclist with chest pain. He subsequently underwent bypass grafting.

(Left) Coronary CT in a 53-year-old man with exertional chest pain and risk factors for coronary artery disease shows a large noncalcified plaque in distal left main. Also note calcified plaque in the proximal LAD. (Right) Corresponding sagittal oblique multiplanar reformat through the LM emphasizes the severity of stenosis of this plaque with only a tiny lumen visible . This case illustrates the utility of isotropic voxel imaging in any image plane with cardiac CT.

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(Left) Oblique cardiac CT shows > 50% stenosis of the LM ostium. Note also extensive mixed plaque along the LAD. Such ostial lesions may occasionally be missed on invasive angiography due to the catheter tip being pushed past the ostial stenosis. (Right) Coronary CT in a 59-year-old man with exertional chest pain shows > 50% stenosis of LM . Nonobstructing calcified plaque is noted in the proximal LAD. Patient underwent bypass grafting.

Coronary Artery Dissection Key Facts Terminology Intimal tear of coronary artery wall with false lumen between adventitia and tunica media Imaging Involved vessel: 60% left anterior descending coronary artery; 30% right coronary artery CTA May show contrast within coronary artery wall outside true lumen Thrombosed false lumen may be difficult to differentiate from noncalcified plaque Transesophageal echography Linear echogenic flap Color Doppler may allow differentiation of true and false lumina Top Differential Diagnoses Thrombus Intraplaque hemorrhage Clinical Issues Presentation may include recurrent angina, acute myocardial infarction in young patient, unexplained sudden heart failure, sudden death, or no symptoms (post procedure) 10-year spontaneous dissection recurrence rate is 29.4% Reports have demonstrated favorable outcomes with conservative management Stent can be used in single-vessel involvement; good results Edge dissections associated with stent deployment do not require treatment CABG is reserved for unstable patients with left main stem or 2-vessel disease &/or severe left ventricular dysfunction

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(Left) Invasive coronary angiogram during percutaneous coronary intervention to a right coronary stenosis shows that a coronary dissection has occurred with contrast material seen dissecting into the wall of the proximal right coronary artery segment and becoming “hung up.” (Right) Corresponding angiogram 10 minutes later (same patient) demonstrates an extension of the dissection retrogradely into the wall off the right sinus of the Valsalva wall .

(Left) Corresponding angiogram 60 seconds later (same patient) shows extension of the dissection upwards along the ascending aortic wall . (Right) Corresponding coronal CTA (same patient) shows that the type A dissection flap is now extending cephalad into the arch and arch vessels . Note that the true lumen is continuous with the aortic valve inflow . P.8:63

TERMINOLOGY Definitions Intimal tear of coronary artery wall with false lumen between adventitia and tunica media IMAGING General Features Best diagnostic clue Contrast in wall of coronary vessel with identifiable dissection flap Thrombus within false lumen is more challenging to diagnose Location 60% left anterior descending coronary artery; 30% right coronary artery Some report that these numbers are reversed in males Multivessel dissection may occur 694

Diagnostic Imaging Cardiovascular CT Findings Cardiac gated CTA May show contrast within coronary artery wall outside true lumen Thrombosed false lumen may be difficult to differentiate from noncalcified plaque Misregistration artifact may mimic dissection Reconstruction of different cardiac phases may result in data set in which artifact line is not persistent, which proves its artificial nature Artifact appears as unusually straight line (not anatomic) along X-Y plane between adjacent slabs Best appreciated on coronal or sagittal oblique reformations Typically extends beyond confines of vessel True dissection may track retrogradely to ostium and extend into aortic wall/aortic dissection Echocardiographic Findings Transesophageal echo Shows linear echogenic flap May demonstrate retrograde extension to aorta wall Color Doppler may allow differentiation of true and false lumina Intravascular ultrasound Can confirm presence of intimal flap May aid placement of stent guidewire into true lumen Can demonstrate contrast (hypoechogenic) or thrombus (gray echogenicity) within false lumen May demonstrate retrograde extension to aorta wall Angiographic Findings Invasive coronary angiography Intimal flap may be apparent as linear filling defect in vessel lumen Spectrum from small benign to large occlusive flap Flap may be mobile or fixed Linear or spiral-shaped false lumen contrast staining May demonstrate retrograde extension into aortic wall Adjunctive imaging modalities may be used to confirm diagnosis Intravascular ultrasound Optical coherence tomography, higher resolution Angioscopy DIFFERENTIAL DIAGNOSIS Thrombus Less often linear May be mobile, making flap differentiation difficult Intraplaque Hemorrhage Not uncommon in complicated plaques and as a result of plaque rupture May have similar clinical sequelae to dissection PATHOLOGY General Features Etiology Spontaneous Peripartum/postpartum Progesterone induces degeneration of medial wall collagen Atherosclerosis Plaque rupture may be complicated not only by intraluminal thrombosis but also by development of deep subintimal dissection Coronary vasculitis Kawasaki disease Polyarteritis nodosa Systemic lupus erythematosus Giant cell arteritis Iatrogenic trauma During coronary intervention Cannulation Advancing guidewire Angioplasty 695

Diagnostic Imaging Cardiovascular Atherectomy Stent deployment Can be found in ˜ 60% of postprocedure examinations Blunt chest trauma Aortic dissection Genetics Predisposed by Ehlers-Danlos syndrome Marfan syndrome Fibromuscular dysplasia Microscopic Features Small cystic spaces in media of coronary vessels Periadventitial eosinophilic infiltrates Unclear if consequence or cause Intimal tear found infrequently at autopsy Disruption of vasa vasorum leading to intramedial hemorrhage and subsequent dissection without intimal tear also has been proposed as possible mechanism CLINICAL ISSUES Presentation Most common signs/symptoms Asymptomatic Asymptomatic in most procedural complications Recurrent angina May cause acute myocardial infarction in young patients P.8:64

Unexplained sudden heart failure in spontaneous dissection Sudden death Demographics Age Young patients Gender Equal gender distribution Natural History & Prognosis Risk of acute occlusion varies depending on degree of dissection ˜ 5-10% acutely occlude Usually in 1st 12 hours after stopping heparin post procedure Spiral and long (> 10 mm) dissections have worse outcomes Ostial lesions undergoing percutaneous coronary intervention have higher risk of retrograde extension into aortic wall Survival Patients who survive acute phase have 2-year survival rate of 95% Recurrence 10-year spontaneous dissection recurrence rate: 29.4% Median time to 2nd episode: 2.8 years Range: 3 days-12 years Treatment No comparative studies of treatment modalities Medical Reports have demonstrated favorable outcomes with conservative management Many small dissections will heal spontaneously Thrombolytics may exacerbate dissections Antithrombotics and antiplatelet therapy can reduce risk of acute thrombosis and occlusion Interventional Placement of stent in single-vessel involvement shows good results Edge dissections associated with stent deployment do not require treatment Surgical Coronary artery bypass graft (CABG) is reserved for unstable patients with 696

Diagnostic Imaging Cardiovascular Left main stem 2-vessel disease Severe left ventricular dysfunction Rarely, orthotopic heart transplant is required Graft from false lumen to right atrium if uncontrolled bleeding from false lumen DIAGNOSTIC CHECKLIST Consider In young patients who present with acute myocardial infarction Intimal flap appears as linear filling defect in vessel lumen SELECTED REFERENCES 1. Bashir M et al: Cardiac transplantation for spontaneous coronary artery dissection. Interact Cardiovasc Thorac Surg. 16(1):91-2, 2013 2. Hoshi T et al: Multimodality intracoronary imaging in spontaneous coronary artery dissection: Impacts of intravascular ultrasound, optical coherence tomography, and coronary angioscopy. Catheter Cardiovasc Interv. 81(3):E151-4, 2013 3. Glamore MJ et al: Spontaneous coronary artery dissection. J Card Surg. 27(1):56-9, 2012 4. Sheikh AS et al: Pregnancy-related spontaneous coronary artery dissection: two case reports and a comprehensive review of literature. Heart Views. 13(2):53-65, 2012 5. Tweet MS et al: Clinical features, management, and prognosis of spontaneous coronary artery dissection. Circulation. 126(5):579-88, 2012 6. Kurum T et al: Spontaneous coronary artery dissection after heavy lifting in a 25-year-old man with coronary risk factors. J Cardiovasc Med (Hagerstown). 7(1):68-70, 2006 7. Ohlmann P et al: Images in cardiovascular medicine. Spontaneous coronary dissection: computed tomography appearance and insights from intravascular ultrasound examination. Circulation. 113(10):e403-5, 2006 8. Tepe SM et al: MRI demonstration of acute myocardial infarction due to posttraumatic coronary artery dissection. Int J Cardiovasc Imaging. 22(1):97-100, 2006 9. van Gaal WJ 3rd et al: Treatment of spontaneous coronary dissection with drug-eluting stents—late clinical, angiographic and IVUS follow up. J Invasive Cardiol. 18(2):E93-4, 2006 10. Butler R et al: Spontaneous dissection of native coronary arteries. Heart. 91(2):223-4, 2005 11. Chai HT et al: Utilization of a double-wire technique to treat long extended spiral dissection of the right coronary artery. Evaluation of incidence and mechanisms. Int Heart J. 46(1):35-44, 2005 12. Gowda RM et al: Clinical perspectives of the primary spontaneous coronary artery dissection. Int J Cardiol. 105(3):334-6, 2005 13. Justice LT et al: Left main dissection and thrombosis in a young athlete. Cardiol Rev. 13(5):260-2, 2005 14. Porto I et al: Intravascular ultrasound imaging in the diagnosis and treatment of spontaneous coronary dissection with drug-eluting stents. J Invasive Cardiol. 16(2):78-80, 2004 15. Rogers JH et al: Coronary artery dissection and perforation complicating percutaneous coronary intervention. J Invasive Cardiol. 16(9):493-9, 2004 16. Roig S et al: Spontaneous coronary artery dissection causing acute coronary syndrome: an early diagnosis implies a good prognosis. Am J Emerg Med. 21(7):549-51, 2003 17. Badmanaban B et al: Spontaneous coronary artery dissection presenting as cardiac tamponade. Ann Thorac Surg. 73(4):1324-6, 2002 18. Kamineni R et al: Spontaneous coronary artery dissection: report of two cases and a 50-year review of the literature. Cardiol Rev. 10(5):279-84, 2002 19. Maresta A et al: Spontaneous coronary dissection of all three coronary arteries: a case description with mediumterm angiographic follow-up. Ital Heart J. 3(12):747-51, 2002 20. Ichiba N et al: Images in cardiovascular medicine. Plaque rupture causing spontaneous coronary artery dissection in a patient with acute myocardial infarction. Circulation. 101(14):1754-5, 2000 P.8:65

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(Left) Oblique invasive coronary angiogram shows a small coronary edge dissection immediately distal to a newly inserted stent . (Right) Curved multiplanar coronary CTA in the same patient shows a corresponding area of contrast in the wall of the coronary artery at the stent edge, consistent with a stent edge dissection. Note the resultant intramural thrombus in the wall of the coronary artery.

(Left) Invasive coronary angiogram shows retrograde extension of contrast from the left main coronary artery backwards into the sinus of Valsalva , where it remains stationary. Note the catheter in the left main coronary artery . (Right) Coronal oblique coronary CTA in the same patient shows intramural contrast extension from the left main coronary artery (stent in situ ) into the sinus of Valsalva wall . Note also the thrombus in the sinus wall .

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(Left) Coronary CTA in a patient post stent insertion into a venous bypass graft shows a thrombus in the graft wall secondary to focal dissection. (Right) Cardiac CTA cross-sectional image across the venous graft in the same patient showed intramural thrombus secondary to focal dissection, which was confirmed by intravascular ultrasound.

Acute Myocardial Infarction Key Facts Terminology Detection of rise &/or fall of cardiac biomarker values (preferably cardiac troponin) and at least 1 of the following Symptoms of ischaemia New or presumed new significant ST-segment T wave changes or new left bundle branch block Development of pathological Q waves in the ECG Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality Identification of an intracoronary thrombus by angiography or autopsy ST-segment elevation myocardial infarction (STEMI) ST-segment elevation or a new left bundle branch block pattern in resting ECG High mortality Non-ST segment elevation myocardial infarction Troponin ↑, but no ST segment ↑ in resting ECG Lower mortality than STEMI Imaging Coronary artery filling defect on invasive coronary angiogram in combination with wall motion abnormalities in the corresponding myocardial segment and increase in myocardial enzymes CTA: Coronary occlusion with noncalcified material (thrombus) MR: T2WI demonstrates increased signal intensity consistent with myocardial edema Top Differential Diagnoses Unstable angina Aortic dissection Pulmonary embolism Acute myocarditis Acute pericarditis Transient left ventricular apical ballooning

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(Left) Multiplanar reconstruction of CECT (transaxial orientation; 8 mm thickness) shows a clearly defined hypoperfusion of the lateral wall of the left ventricle (LV) . This is the appearance of acute myocardial infarction (MI) (ST-segment elevation MI [STEMI] or non-ST segment elevation MI [NSTEMI]) in CECT. (Right) Contrast-enhanced coronary CT angiography in the same patient reveals an occlusion of the intermediate branch (ramus) .

(Left) LV short-axis late gadolinium enhancement MR image demonstrates subendocardial nontransmural delayed hyperenhancement on the otherwise normal (black) LV myocardium, consistent with nontransmural infarct in the left anterior descending (LAD) coronary artery territory. Note normal wall thickness, which is typically seen in the acute setting. (Right) Axial CT in the same patient demonstrates normal wall thickness with subendocardial lowattenuation perfusion defect in the LAD territory. P.8:67

TERMINOLOGY Abbreviations Myocardial infarction (MI) Definitions Detection of rise &/or fall of cardiac biomarker values (preferably cardiac troponin) and ≥ 1 of the following Symptoms of ischaemia New or presumed new significant ST-segment T wave changes or new left bundle branch block Development of pathological Q waves on ECG Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality Identification of intracoronary thrombus by angiography or autopsy MI is acute coronary syndrome 700

Diagnostic Imaging Cardiovascular Acute coronary syndromes are divided into 3 groups ST-segment elevation MI (STEMI) Non-ST segment elevation MI (NSTEMI) Unstable angina pectoris IMAGING General Features Best diagnostic clue Filling defect on invasive coronary angiogram + wall motion abnormalities in corresponding myocardial segment and ↑ myocardial enzymes General findings Diminished perfusion and function of affected area Reduced regional contractility Hypokinesis: Decreased systolic thickening Akinesis: No contraction Dyskinesis: Paradoxical outward motion in systole Increased cell membrane permeability Increased uptake of extracellular agents Leakage of intracellular proteins and enzymes Altered regional metabolism Radiographic Findings Radiography Chest radiography findings Abnormal findings are rare in acute setting Interstitial edema if heart failure ensues Abnormal cardiac silhouette Sudden severe pulmonary edema in papillary muscle rupture with subsequent mitral regurgitation → poor prognosis CT Findings CTA Coronary occlusion with noncalcified material (e.g., thrombus) May demonstrate regional wall motion abnormality and perfusion deficit Left ventricular (LV) thinning and presence of calcifications may differentiate chronic from acute MI Fatty metaplasia in chronic infarct if negative HU MR Findings T2WI Affected area demonstrates increased signal intensity consistent with myocardial edema T1WI C+ Infarcted area may demonstrate late enhancement after gadolinium MR cine ↓ regional wall motion and systolic wall thickening ↓ ejection fraction but could be preserved due to compensation from remote myocardium May demonstrate mitral regurgitation if inferior MI involves posteromedial papillary muscle 1st-pass perfusion Reduced wash-in of contrast agent (perfusion deficit) Delayed enhancement Seen in infarcted area due to myocardial necrosis Central hypointense region surrounded by delayed enhancement represents microvascular obstruction Microvascular obstruction indicates worse prognosis Degree of transmurality of delayed enhancement may predict LV functional recovery > 75% transmurality in acute setting = no recovery in 6 months in spite of revascularization Gold standard for functional assessment; ejection fraction, LV end-diastolic/systolic volumes, LV mass Best modality to assess MI complications (true aneurysm, false aneurysm, ventricular septal rupture) Echocardiographic Findings Echocardiogram Altered ventricular function Reduced regional function: Hypokinesis, akinesis, or dyskinesis Decrease in global ventricular ejection fraction is possible, but global function may be preserved Color Doppler Mitral regurgitation due to papillary muscle dysfunction is possible 701

Diagnostic Imaging Cardiovascular Angiographic Findings Invasive coronary angiography Occluded coronary artery Patent but stenotic coronary artery, or plaque disruption May show evidence of thrombus (central filling defect surrounded by contrast or haziness of lumen) Flow in coronary artery may be reduced Thrombolysis in MI (TIMI) risk score TIMI 0: Absence of antegrade flow beyond coronary occlusion TIMI 1: Faint antegrade coronary flow beyond occlusion with incomplete filling of distal coronary bed TIMI 2: Delayed or sluggish antegrade flow with complete filling of distal territory TIMI 3: Normal flow that completely fills the distal coronary bed Ventriculography, if performed, shows reduced regional wall motion and ejection fraction Nuclear Medicine Findings Radionuclide angiography Reduced overall ejection fraction Regional myocardial dysfunction Aneurysm formation; dyskinesis Myocardial scintigraphy Fixed defect of reduced or absent tracer uptake (at stress and rest imaging) Increased chamber size P.8:68

No redistribution of thallium No reinjection uptake of Tc-99m perfusion tracer Imaging Recommendations Best imaging tool Echocardiography to identify area of wall motion abnormality and determine global LV function Cardiac catheterization for immediate intervention DIFFERENTIAL DIAGNOSIS Old Myocardial Infarction Wall motion abnormalities Persistent hyperenhancement on MR Absent tracer uptake on scintigraphy T2WI will not demonstrate peri-infarct signal increase (no edema) Thinned LV wall, presence of calcium, fatty metaplasia, and aneurysm indicate old infarct Unstable Angina Acute coronary syndrome without myocardial necrosis Accelerating or “crescendo” pattern of chest pain at rest Cardiac enzymes are not elevated; significant stenosis by angiography or positive test for myocardial ischemia Acute Myocarditis Typical presentation: Chest pain, increased cardiac enzymes, and normal cardiac catheterization MR is fundamental for diagnosis Late gadolinium enhancement MR demonstrates focal edema and hyperenhancement in distribution that is not typical for coronary artery segments Wall motion abnormalities may be associated Cell membrane integrity is compromised Acute Pericarditis Acute chest pain; ECG changes that are very similar to MI (ST-segment elevation possible) Myocardial enzymes remain normal unless myocardium is involved in inflammatory process (perimyocarditis) No wall motion abnormalities Coronary arteries normal Coronary Vasospasm Prinzmetal angina Syndrome of chest pain at rest secondary to myocardial ischemia associated with ST-segment elevation Transient Left Ventricular Apical Ballooning a.k.a. Takotsubo cardiomyopathy, stress-induced cardiomyopathy, and broken heart syndrome

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Diagnostic Imaging Cardiovascular Reversible LV dysfunction with large apical akinesia (“ballooning” and hypercontractility of basal myocardial segments) Normal coronary arteries on invasive angiography Often preceded by traumatic emotional experience LV function returns to normal within several weeks MR may detect myocardial edema PATHOLOGY General Features Etiology Most frequent mechanism is atherosclerotic plaque rupture followed by thrombosis and acute coronary occlusion leading to myocardial necrosis Myocardial necrosis CLINICAL ISSUES Presentation Most common signs/symptoms Chest tightness and pain; substernal, pressing, occasionally radiating to left arm Associated with dyspnea, nausea, palpitations, radiation to jaw Can be completely asymptomatic, especially in patients with diabetes Clinical profile High risk of ventricular arrhythmias and death Presence of ST-segment elevation in ECG indicates particularly high risk Urgent revascularization required when high-risk features (e.g., ST-segment elevation, ongoing chest pain, hemodynamic instability) are present Normal ECG does not exclude acute infarct (NSTEMI) Treatment STEMI No further testing or imaging to avoid any time delay Immediate coronary angiography and PCI of culprit vessel if possible Thrombolysis if diagnosis is certain and transfer to PCI would require > 90 minutes NSTEMI Always test to rule out differential diagnoses Coronary angiography within 120 minutes in high-risk situations (e.g., ongoing chest pain, troponin elevation, previous bypass surgery, presence of arrhythmias or hypotension) DIAGNOSTIC CHECKLIST Consider ST elevation and ↑ cardiac enzymes are diagnostic for acute STEMI and prompt immediate coronary angiography and intervention Echocardiography is important in patients with suspected NSTEMI to establish diagnosis, identify differential diagnoses, and detect complications Cardiac CT and MR may be useful in patients with unclear diagnosis of acute coronary syndrome Acute aortic dissection and pulmonary embolism are important differential diagnoses Image Interpretation Pearls Cardiac CT can assess not only coronary stenosis/occlusion but also myocardial perfusion and, if performed with retrospective gating, global and regional LV function Best cardiac MR tool to identify acute infarct is imaging of edema (T2WI) SELECTED REFERENCES 1. Friedrich MG: Tissue characterization of acute myocardial infarction and myocarditis by cardiac magnetic resonance. JACC Cardiovasc Imaging. 1(5):652-62, 2008 P.8:69

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(Left) Short-axis SSFP MR shows acute LAD territory MI and chronic right coronary artery territory MI . Image was obtained after Gd administration prior to LGE acquisition; thus, both LGE and T2 edema are seen in acute MI. (Right) Short-axis T2WI, 1-st pass perfusion, SSFP, and LGE images in same patient demonstrate edema , subendocardial perfusion defect , and LGE but normal thickness anteroseptal LV wall, consistent with acute MI. Note inferior chronic MI and ventricular thrombus .

(Left) Multiplanar reconstruction of CECT (4-chamber view; 8 mm thickness) shows acute NSTEMI. Typical hypoperfusion of the left posterolateral myocardium is seen. (Right) CECT short-axis view of the left ventricle in the same patient shows typical hypoperfusion of the left posterolateral myocardium.

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(Left) Modified apical 4-chamber view of acute apical myocardial infarction in echocardiography shows normal cardiac cavities in diastole. (LV = left ventricle; RV = right ventricle; LA = left atrium; RA = right atrium.) (Right) Systolic image shows an akinetic area in the apical region of the left ventricle .

Chronic Myocardial Infarction Key Facts Imaging Late gadolinium enhancement MR Gold standard for detection of myocardial infarction and assessment of viability MR Subendocardial delayed hyperenhancement present with both acute and chronic myocardial infarctions Wall thinning and absent edema on T2-weighted images suggests chronicity CT Linear myocardial calcification or subendocardial fatty metaplasia is highly specific for chronic myocardial infarction Complications include intraventricular thrombus and ventricular aneurysm Top Differential Diagnoses Acute myocardial infarction Nonischemic cardiomyopathies Endocardial fibroelastosis Arrhythmogenic right ventricular dysplasia Constrictive pericarditis Diagnostic Checklist MR Subendocardial delayed enhancement in coronary territory Absent T2 edema Myocardial wall thinning and motion abnormality CT Subendocardial fatty metaplasia and linear calcification Wall thinning and motion abnormality Describe coronary territory and assess for culprit lesion True or false aneurysm Intraventricular thrombus

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(Left) Axial cardiac CT shows marked thinning and aneurysmal dilatation of the left ventricular apex , indicating remote transmural myocardial infarction in the left anterior descending coronary artery territory. (Right) Leftventricular short-axis LGE MR in a patient with remote infarct and recent onset of arrhythmias shows infarct in the right coronary artery territory with nontransmural delayed hyperenhancement . Note the transmural right ventricular infarct .

(Left) Oblique cardiac CT shows wall thinning and transmural calcification in the right coronary artery territory, indicating remote transmural infarct in the right coronary artery territory. Note the unrelated mitral annular calcification . (Right) Axial cardiac CT shows a large lateral wall aneurysm with wall thinning, linear calcification and mural thrombus . P.8:71

TERMINOLOGY Synonyms Remote infarct Definitions No exact definition of minimum amount of time after acute infarction However, if time after acute infarction is ≥ 8 weeks, it is generally accepted as chronic myocardial infarct (MI) Acute MI: Myocardial cell death due to prolonged ischemia IMAGING General Features Best diagnostic clue 706

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Diagnostic Imaging Cardiovascular Linear myocardial calcification or subendocardial fatty metaplasia on CT are diagnostic of remote MI Findings follow coronary vascular distribution Myocardial thinning with akinesis or dyskinesis Myocardial aneurysm or pseudoaneurysm Delayed hyperenhancement without increased T2 signal Location Delayed enhancement or fatty metaplasia are subendocardial and may or may not be transmural Usually confined to coronary territory (or branch territory) Delayed enhancement that is not subendocardial is nonischemic in nature Size Depends on location of culprit lesion(s) The more proximal the culprit lesion, the larger the infarct territory General findings Regional wall motion abnormality Hypokinesis: Decreased systolic thickening/contraction Akinesis: No systolic thickening/contraction Dyskinesis: No contraction and paradoxical motion Regional myocardial thinning Degree of thinning ranges from few millimeters in remote transmural MI to near-normal thickness in small subendocardial nontransmural MI Imaging Recommendations Best imaging tool Cardiac MR with delayed enhancement is highly sensitive and may depict smaller subendocardial defects PET and SPECT demonstrate fixed defects but may miss smaller nontransmural infarcts Linear calcification or fatty metaplasia detected on cardiac CT are diagnostic of remote MI Absence of these findings does not necessarily exclude nontransmural chronic MI Protocol advice MR viability protocol consists of function, T2-weighted fast spin-echo, 1st-pass perfusion, and delayed enhancement acquisitions T2-weighted sequence may help differentiate acute from chronic MI Radiographic Findings Radiography Cardiomegaly Enlarged left ventricle (LV) from aneurysm, pseudoaneurysm, or dilated LV Enlarged left atrium due to functional mitral valve regurgitation or increased filling pressures Pulmonary venous hypertension secondary to mitral valve regurgitation or increased filling pressures Myocardial calcifications indicate remote infarct Must be differentiated from pericardial calcification in constrictive pericarditis MR Findings T2WI Absence of T2 prolongation (bright tissue) indicates absence of edema Edema may be present in acute MI, but chronic MI may coexist MR cine Akinesis, hypokinesis, or dyskinesis, depending on amount of remaining viable myocardium Possible mural thrombus demonstrates absence of systolic thickening Delayed enhancement Delayed hyperenhancement must be based on subendocardial layer Variable degree of transmurality depends on infarct size Calcification will cause signal void within delayed hyperenhancement Most sensitive test for infarcted myocardium in vivo Helps differentiate myocardium from mural thrombus 1st-pass perfusion Subendocardial perfusion defects in coronary territory Helps delineate myocardium and mural thrombus CT Findings NECT Linear low attenuation (fat density, negative HU) within LV myocardium Linear calcification of myocardium Enlarged LV 707

Diagnostic Imaging Cardiovascular Secondary findings of sequela of chronic myocardial infarction Enlarged left atrium Pulmonary findings of pulmonary venous hypertension CTA Linear calcification or fatty infiltration of subendocardial layers of LV myocardium on CT is diagnostic of remote MI Typically (but not always) myocardial thinning LV aneurysm Cardiac gated CTA Functional images demonstrate hypokinesis, akinesis, or dyskinesis, depending on transmurality of infarct Very small remote infarcts may have normal wall thickness and normal wall motion Obstructive coronary artery disease in matching coronary territory Echocardiographic Findings Chronic LV remodeling P.8:72

Infarcted segments wall is thinner, and echo is more dense compared with noninfarcted segments May demonstrate presence of aneurysm or pseudoaneurysm Akinesis or dyskinesis of affected segments Functional mitral regurgitation Abnormal coaptation secondary to tethering from LV dilatation/remodeling May detect mural thrombus Nuclear Medicine Findings LV wall thinning with fixed defect Akinesis in areas of fixed defects Visualization of right ventricle plus high lung uptake are signs of severe LV dysfunction Angiographic Findings Coronary angiography may demonstrate signs of chronic coronary artery disease, not necessarily chronic MI Severe coronary calcifications Collaterals Left ventriculogram may demonstrate findings secondary to chronic MI Dilated LV Aneurysm Mitral regurgitation Wall motion abnormality DIFFERENTIAL DIAGNOSIS Acute Myocardial Infarction Maintained myocardial thickness Increased T2 signal (edema) No fatty metaplasia, calcification, or aneurysm Nonischemic Cardiomyopathies Nonischemic myocardial fibrosis or scar manifests in various patterns of delayed hyperenhancement Invariably, sparing of subendocardium Allows for easy differentiation from ischemic infarct Endocardial Fibroelastosis Delayed enhancement of endocardium Apical obliteration of ventricles, mitral and tricuspid regurgitation (distorted valve apparatus) with markedly enlarged atria, pericardial effusions Arrhythmogenic Right Ventricular Dysplasia Fatty infiltration not subendocardial, usually in right ventricle, occasionally in LV Constrictive Pericarditis Calcifications of pericardium with sparing of myocardium PATHOLOGY Gross Pathologic & Surgical Features Thin plate of scar ± aneurysm or pseudoaneurysm Mural thrombus is commonly present Microscopic Features 708

Diagnostic Imaging Cardiovascular Established scarring with collagen fibers CLINICAL ISSUES Natural History & Prognosis LV remodeling LV dilatation Increase in end-diastolic and end-systolic volumes are predictive of increased mortality May develop ischemic dilated cardiomyopathy May develop mitral regurgitation from remodeling and change of chordae tendineae geometry and resulting mitral valve malcoaptation May develop aneurysm or pseudoaneurysms Pseudoaneurysms are uncommon at anterior apical walls Commonly at basal posterior and lateral walls May develop thrombus Best evaluated on contrast-enhanced MR; detects over 2× as many thrombi as echocardiography Thrombus has lower attenuation than myocardium and does not enhance on contrast-enhanced CT and MR Treatment Medical treatment Surgical treatment Coronary artery bypass grafts if viable myocardium exists Dor procedure (named after Dr. Vincent Dor, who developed and frequently performed the procedure in 1980s) Resection of aneurysm with patch aneurysmorrhaphy Linear aneurysmectomy Aneurysm is resected and the edges are closed in linear vertical fashion using 2 parallel layers of Teflon felt DIAGNOSTIC CHECKLIST Image Interpretation Pearls True aneurysm Wide neck/base Wall consists of endocardium, myocardium, and epicardium ± mural thrombus Low risk of rupture Pseudoaneurysm (false aneurysm) Narrow base/neck Wall consists of epi-/pericardium ± thrombus Higher risk of rupture SELECTED REFERENCES 1. Kim HW et al: Cardiovascular magnetic resonance in patients with myocardial infarction: current and emerging applications. J Am Coll Cardiol. 55(1):1-16, 2009 2. Saeed M et al: Discrimination of myocardial acute and chronic (scar) infarctions on delayed contrast enhanced magnetic resonance imaging with intravascular magnetic resonance contrast media. J Am Coll Cardiol. 48(10):1961-8, 2006 3. Kramer CM et al: Dissociation between changes in intramyocardial function and left ventricular volumes in the eight weeks after first anterior myocardial infarction. J Am Coll Cardiol. 30(7):1625-32, 1997 P.8:73

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(Left) Axial MR cine demonstrates an akinetic lateral wall aneurysm . (Right) Short-axis delayed-enhancement MR shows transmural subendocardial delayed hyperenhancement and wall thinning within the aneurysm.

(Left) Left ventricular short-axis delayed-enhancement MR shows hyperenhancement (infarct) of the right ventricular and left ventricular inferior and inferolateral walls, which have developed a large aneurysm . Note the unenhanced mural thrombus. (Right) Oblique cardiac CT images in a patient post coronary artery bypass graft surgery and left ventricular aneurysmectomy shows 2 parallel layers of Teflon left at the resection site, indicating linear aneurysmectomy.

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(Left) Axial CTA shows a thinned and calcified myocardium and apical aneurysm. Note that the mural thrombus is hypodense (unenhanced) compared with the remote normal myocardium. (Right) Axial coronary CTA shows linear subendocardial fatty metaplasia but relatively preserved myocardial thickness, indicating remote nontransmural infarct in the diagonal branch or obtuse marginal branch territory.

Infarction LAD Distribution Key Facts Terminology Partial/total occlusion of left anterior descending (LAD) coronary artery Imaging Coronary CTA (64 slices) has high sensitivity (98%), specificity (88%), and negative predictive value (95-100%) for detection of hemodynamically significant stenosis 1st-pass CT perfusion may show anterior/anteroseptal wall myocardial hypoperfusion defects Late-enhancement MR can demonstrate presence, location, and size of infarction MR is gold standard for assessing regional wall motion using steady-state free precession sequence Echo shows anterior/anteroseptal segment akinesis acutely, thinning chronically, and complications of LAD infarction Top Differential Diagnoses Acute aortic dissection Acute myocarditis Acute pulmonary embolism Reflux esophagitis Takotsubo syndrome Clinical Issues Reperfusion therapy: Indicated in all patients with symptoms of < 12 hours duration and persistent ST-segment elevation or (presumed) new left bundle branch block Primary PCI: Recommended reperfusion therapy over fibrinolysis within 120 minutes of symptom onset CABG: May also be indicated in patients in cardiogenic shock if coronary anatomy is not amenable to PCI, or at time of repair for patients with mechanical complications

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(Left) Coronary CTA shows an abrupt stenosis of the mid segment left anterior descending (LAD) coronary artery . Note diffuse narrowing in the distal portion and extensive calcified plaque in the left main coronary artery and proximal segment LAD . (Right) Corresponding invasive angiogram confirms an abrupt stenosis of the mid segment LAD and diffusely diseased distal portion . Identifying the LAD on invasive angiography can be done by looking for the septal branches .

(Left) Corresponding adenosine stress perfusion MR shows a subendocardial perfusion defect in the left ventricular (LV) anteroseptal segment at the mid ventricular level. (Right) Corresponding late-enhancement (LE) cardiac MR shows essentially transmural acute myocardial infarct of the LV interventricular septum at the mid and apical ventricular levels in the typical LAD vascular territory. Note also LE of the inferior apex , typical of a wraparound LAD. Usually, an infarct is larger than a perfusion defect. P.8:75

IMAGING General Features Best diagnostic clue Partial/total occlusion of left anterior descending (LAD) coronary artery on various imaging modalities Subendocardial or transmural delayed hyperenhancement (acute or chronic), fatty metaplasia, or linear calcification (chronic) Location Infarct in anterior and septal segments extending to apex or inferior apical wall Culprit lesion Proximal LAD: Proximal to 1st septal perforator 712

Diagnostic Imaging Cardiovascular Mid LAD: Distal to 1st septal perforator, proximal to large diagonal Distal LAD: Distal to large diagonal Radiographic Findings Radiography Chest radiography findings Interstitial edema if heart failure ensues Abnormal cardiac silhouette if apical aneurysm in chronic myocardial infarction (MI); may calcify CT Findings CTA Coronary CTA (64 slices) has high sensitivity (98%), specificity (88%), and negative predictive value (95100%) for detection of hemodynamically significant stenosis CT perfusion (CTP) 1st-pass perfusion data derived from CTA data Anterior and anteroseptal wall myocardial hypoperfusion defect CT viability Requires 2 scans: Conventional CTA and then delayed scan to identify late contrast hyperenhancement of myocardium In setting of acute MI, loss of membrane integrity increases volume of distribution of contrast In chronic scar tissue, myocytes are replaced with collagenous matrix resulting in increasing interstitial (extracellular) space Both processes lead to hyperenhancement on delayed imaging Chronic infarction is characterized by wall thinning, calcification, left ventricular (LV) remodeling, and fatty replacement MR Findings T2WI May show high signal in acute MI due to tissue edema Delayed enhancement Perfusion 1st-pass perfusion (stress followed by rest) Hybrid gradient-echo planar sequence acquired during bolus of 0.1 mmol/kg gadolinium Viability 7-10 minutes after bolus of 0.1-0.2 mmol/kg gadolinium Gradient-echo double inversion-recovery sequence Vary inversion time (TI) to maximize nulling of normal myocardium Late enhancement can demonstrate presence, location, and size of infarction Healthy viable myocardium appears black Scar or infarct appears enhanced Degree of transmurality of late gadolinium enhancement determines viability (> 50% of wall thickness infarcted indicates nonviability) LAD infarction results in anterior and anteroseptal segment subendocardial hyperenhancement Regional wall motion MR is gold standard for chamber volumetrics Steady-state free precession sequence is most widely used Echocardiographic Findings Echocardiogram Standardized 17-segment American Heart Association model utilized Echo shows anterior/anteroseptal segment akinesis acutely, anterior/anteroseptal segment thinning chronically Chronic infarction appears bright = fatty replacement Echo is very useful bedside exam for complications of LAD infarction LV thrombus, aneurysms/pseudoaneurysms, Dressler syndrome, postinfarction mitral regurgitation, papillary muscle rupture Angiographic Findings Ventriculography Reduced anterior-apical wall motion and ejection fraction Dyskinesis or reduced wall thickening Invasive coronary angiography Invasive angiography remains clinical gold standard for detecting LAD stenosis/occlusion Nuclear Medicine Findings 713

Diagnostic Imaging Cardiovascular PET Image intensity reflects organ function Viability Gold standard for myocardial viability Glucose metabolism is preferred over β-oxidation of fatty acids if ischemia 5-fluoro deoxyglucose tracer is taken up by viable myocardium and trapped Regional increases in FDG uptake relative to regional myocardial blood flow (i.e., perfusionmetabolism mismatch) signify myocardial viability Hybrid PET/CT scanner shows complementary anatomical and physiological data Perfusion Quality of regional myocardial blood flow Most commonly used tracers are rubidium-82 and ammonia N-13 Performed under stress and rest conditions Can be used to calculate coronary flow reserve (stress/rest blood flow) Sensitivity of 92% and specificity of 85% for significant CAD (defined as > 50%) Quantity of regional myocardial blood flow Most commonly used tracer is oxygen-15 water SPECT Technetium-99m P.8:76

Tc-99m-based sestamibi and tetrofosmin are lipid-soluble compounds that are retained in mitochondria requiring intact mitochondrial membrane and oxidative metabolism Can demonstrate infarct size but does not have spatial resolution of CT/MR Perfusion study can show viable myocardium Segments with > 50-60% uptake are considered viable Sensitivity and specificity for improvement postrevascularization: 81% and 66%, respectively Thallium scan Potassium analogue: Uptake determined by blood flow Washout dependent on membrane Na+/K+ ATPase 2 protocols Stress-redistribution-reinjection: Can assess for stress-inducible ischemia and viability Rest-redistribution: Only assesses viability Viable segments are considered when tracer uptake increases > 10% or when activity > 50-60% Sensitivity and specificity for improvement postrevascularization: 86% and 59%, respectively DIFFERENTIAL DIAGNOSIS Conditions With Overlapping Symptoms Acute aortic dissection Acute myocarditis Acute pulmonary embolism Reflux esophagitis Takotsubo syndrome PATHOLOGY General Features Vascular occlusion with anterior-apical necrosis Myocardial thinning with LV thrombosis (40%) Gross Pathologic & Surgical Features Initiating event: Fissure in diseased plaque cap Results in exposure of subendothelial matrix elements, which stimulates platelet activation/clot formation CLINICAL ISSUES Presentation Most common signs/symptoms Central, crushing chest pain radiating to left arm Cardiogenic shock if large area of LV is ischemic Other signs/symptoms Atypical pain in jaw, epigastrium Nausea, vomiting, diaphoresis 714

Diagnostic Imaging Cardiovascular Left bundle branch block if His-Purkinje tissue is ischemic in proximal LAD infarction No conduction disturbance if lesion is mid or distal Clinical profile Risk factors: Smoking, cholesterol elevation, diabetes, hypertension, family history Natural History & Prognosis LAD infarction has higher rate of infarct expansion with potential for aneurysm and rupture LAD infarction has higher rate of LV thrombus Treatment Reperfusion therapy is indicated in all patients with symptoms of < 12 hours duration and persistent ST-segment elevation or (presumed) new left bundle branch block Reperfusion therapy (preferably primary PCI) is indicated if evidence of ongoing ischemia, even if symptoms have started > 12 hours beforehand or if pain and ECG changes have been stuttering Medical Analgesia is managed with nitrates and opioids Dual antiplatelet therapy (DAPT) is preferred Fibrinolytic therapy is recommended within 12 hours of symptom onset if primary PCI cannot be performed within 120 minutes of symptom onset β-blockers: Benefit is extrapolated from earlier trials Interventional Primary PCI is recommended reperfusion therapy over fibrinolysis within 120 minutes of symptom onset DAPT with aspirin and an adenosine diphosphate (ADP) receptor blocker (prasugrel or ticagrelor is preferred), as early as possible before angiography, and parenteral anticoagulant (bivalirudin is preferred) If no contraindications to prolonged DAPT, drug-eluting stent is preferred over bare metal stent Only infarct-related artery should be treated during initial intervention Surgical CABG may also be indicated in patients in cardiogenic shock if coronary anatomy is not amenable to PCI, or at time of repair for patients with mechanical complications All patients should have echocardiography for assessment of infarct size/LV function SELECTED REFERENCES 1. Salavati A et al: Dual-source computed tomography angiography for diagnosis and assessment of coronary artery disease: systematic review and meta-analysis. J Cardiovasc Comput Tomogr. 6(2):78-90, 2012 2. So A et al: Dual-energy CT and its potential use for quantitative myocardial CT perfusion. J Cardiovasc Comput Tomogr. 6(5):308-17, 2012 3. So A et al: Prospectively ECG-triggered rapid kV-switching dual-energy CT for quantitative imaging of myocardial perfusion. JACC Cardiovasc Imaging. 5(8):829-36, 2012 4. Task Force on the management of ST-segment elevation acute myocardial infarction of the European Society of Cardiology (ESC) et al: ESC Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation. Eur Heart J. 33(20):2569-619, 2012 5. Florian A et al: Cardiac magnetic resonance imaging in ischemic heart disease: a clinical review. J Med Life. 4(4):33045, 2011 6. Notghi A et al: Myocardial perfusion scintigraphy: past, present and future. Br J Radiol. 84 Spec No 3:S229-36, 2011 7. Pakkal M et al: Non-invasive imaging in coronary artery disease including anatomical and functional evaluation of ischaemia and viability assessment. Br J Radiol. 84 Spec No 3:S280-95, 2011 8. Mendoza DD et al: Viability imaging by cardiac computed tomography. J Cardiovasc Comput Tomogr. 4(2):83-91, 2010 9. Dilsizian V et al: PET myocardial perfusion and metabolism clinical imaging. J Nucl Cardiol. 16:651, 2009 P.8:77

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(Left) Invasive coronary angiogram shows a high-grade obstructive stenosis of the proximal mid segment LAD . (Right) Corresponding late-enhanced cardiac MR image shows extensive LE in the interventricular septum , consistent with acute myocardial infarction in the LAD vascular territory. Note wraparound LAD pattern . Multiple areas of low signal within the infarct correspond to areas of microvascular obstruction (associated with a poorer post-infarction prognosis).

(Left) Black blood T2 short-axis image shows transmural high signal of the LV anterior and anteroseptal myocardial segments, consistent with acute myocardial edema in the LAD vascular territory. Note anteroseptal segment hypertrophy secondary to edema. (Right) Corresponding LE image shows an essentially transmural infarct of the LV anteroseptal segment . Note that the LE area is smaller than the T2 high-signal area, indicating a large area at risk on T2 sequence.

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(Left) Invasive coronary angiogram shows acutely occluded proximal segment LAD . Note acute thrombus in the lumen. (Right) Corresponding LE cardiac MR 2-chamber view shows an extensive acute transmural infarct affecting the basal, mid, and apical anterior myocardial segments (LAD territory). Note multiple low-signal mural nodules , consistent with mural thrombus. Note different location compared with microvascular obstruction, which occurs within the myocardium.

Papillary Muscle Rupture Key Facts Terminology Partial or complete rupture of a papillary muscle, most commonly in setting of acute myocardial infarction Imaging Flail of chordae &/or papillary muscle into left atrium along with severe mitral regurgitation on several imaging modalities MR may show late enhancement of affected papillary muscle Transthoracic echo has sensitivity of 65-85%; often initial modality Transesophageal echo improves sensitivity to 95-100% due to proximity of mitral apparatus to transducer CTA may show myocardial perfusion defect in acute myocardial infarction CTA cine multiphase reconstructions can show global and regional left ventricular abnormalities related to acute myocardial infarction Top Differential Diagnoses Cardiogenic shock Ischemic mitral regurgitation Chordal rupture Dilated mitral annulus Endocarditis Ventricular septal rupture Clinical Issues Most commonly presents 2-9 days post acute myocardial infarction with acute-onset chest pain and shortness of breath Stabilize patient with afterload and preload reduction Intraaortic balloon pump is frequently required Once stabilized, early surgery is essential

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(Left) Chest radiograph shows unilateral acute pulmonary edema in a patient presenting with acute myocardial infarction. The unilateral appearance is classic for severe mitral regurgitation directed into the right-sided pulmonary veins secondary to papillary muscle rupture. (Right) Corresponding chest CT scan confirms unilateral right-sided acute pulmonary edema . Note also bilateral pleural effusions typical of left ventricular failure.

(Left) Three-chamber echocardiogram in the same patient shows a prolapsing posterior mitral valve leaflet into the left atrium. Note complete lack of connection of the leaflet tip with a papillary muscle. (Right) Three-chamber color Doppler echocardiogram in the same patient shows a large eccentric mitral regurgitant jet into the left atrium. Papillary muscle rupture was confirmed later during surgery. P.8:79

TERMINOLOGY Definitions Partial or complete rupture of a papillary muscle, most commonly in setting of acute myocardial infarction IMAGING General Features Best diagnostic clue Flail chordae &/or papillary muscle prolapse into left atrium along with severe mitral regurgitation Location Posteromedial papillary muscle in 75% of cases given single blood supply from posterior descending branch of a dominant right coronary artery

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Diagnostic Imaging Cardiovascular Anterolateral muscle rupture in 25% of cases, as it tends to have dual blood supplies from 1st obtuse marginal branch (originating from left circumflex coronary artery) and from 1st diagonal branch (originating from left anterior descending coronary artery) Size Partial rupture (affecting a single head) is more common than complete rupture (affecting papillary muscle trunk) Morphology Both anterior and posterior leaflets of valve are attached via primary, secondary, and tertiary chordae to both anterolateral and posteromedial papillary muscles Disruption in either papillary muscle can result in dysfunction of anterior or posterior leaflets Radiographic Findings Radiography Chest radiography findings Pulmonary venous congestion with signs of pulmonary edema No evidence of left atrial enlargement in acute setting Right upper lobe edema is specific chest x-ray finding Caused by mitral leaflet flail and jet of regurgitant blood directed into right superior pulmonary vein CT Findings CTA Coronary arteries can be evaluated for significant coronary stenosis Myocardial perfusion defect may be detected in acute myocardial infarction Cine multiphasic reconstructions can show Prolapse of chordae and mitral leaflet into left atrium Global and regional left ventricular function abnormalities related to acute myocardial infarction MR Findings MR cine Can show Prolapse of chordae and mitral leaflet into left atrium and regurgitant jet Global and regional left ventricular function abnormalities related to acute myocardial infarction Delayed enhancement Late enhancement of affected papillary muscle Can quantify extent of acute myocardial infarction (if that is the cause) Echocardiographic Findings Echocardiogram Transthoracic echography Often initial modality Sensitivity of 65-85% Transesophageal echography Improves sensitivity to 95-100% due to proximity of mitral apparatus to transducer in esophageal position Papillary muscle head in left atrium or left ventricle Severe mitral regurgitation by color Doppler with broad vena contracta Eccentric jet with normal-sized left atrium is common Angiographic Findings Ventriculography Severe mitral regurgitation Flail leaflet and papillary muscle head will frequently be apparent Imaging Recommendations Best imaging tool Transesophageal echography if patient is stable DIFFERENTIAL DIAGNOSIS Cardiogenic Shock Prior myocardial infarction is usually present Multivessel or left main coronary disease Evident from any modality that overall function is severely reduced Ischemic Mitral Regurgitation 719

Diagnostic Imaging Cardiovascular Neighboring myocardium usually shows marked regional wall motion abnormality Left ventricular remodeling changes geometry of chordae tendinea, leading to mitral valve malcoaptation Lateral displacement of lateral wall changes angle of chordae (relative shortening) and results in incomplete systolic closure of posterior mitral valve leaflet No flail leaflet Lesser degree of regurgitation Dilated Mitral Annulus More commonly associated with dilated left ventricle Chordal Rupture May have same consequence as papillary muscle rupture and is difficult to distinguish May require transesophageal echocardiography to distinguish from papillary muscle rupture Lesser degree of regurgitation is sometimes noted Endocarditis Vegetation may appear as mobile structure attached to regurgitant valve Very different clinical setting Patient is usually septic P.8:80

Blood cultures are helpful in diagnosis Ventricular Septal Rupture Post-myocardial infarction rupture of septum leading to ventricular septal defect No mitral valve regurgitation PATHOLOGY General Features Etiology Typically ischemic Traumatic Endocarditis Prone to ischemia as central artery of papillary muscle is an end artery More commonly involves posterior papillary muscle (3× more common) Rupture most often at papillary muscle head May be partial or complete Typical necrosis apparent at site of rupture Myocardial infarct size itself may not be large CLINICAL ISSUES Presentation Most common signs/symptoms Most commonly presents 2-9 days post acute myocardial infarction Acute chest pain Acute shortness of breath Sudden onset of heart failure Systolic function is better than anticipated, or hyperdynamic, in setting of hemodynamic compromise Severe mitral regurgitation: Detectable by several modalities Clinically Systolic murmur at apex, though may be very faint or absent Absent murmur represents rapid equalization of pressure across mitral valve Radiologically Echocardiography is a rapid bedside means of diagnosis Clinical profile Smoking Cholesterol elevation Diabetes Hypertension Family history Prior myocardial infarction Natural History & Prognosis Usually occurs at 1st infarct 720

Diagnostic Imaging Cardiovascular Papillary muscle rupture is seen in 1-3% of patients with acute myocardial infarction Survival rates seem related to extent of papillary muscle rupture Treatment Medical Stabilize patient with Afterload reduction Preload reduction Interventional Coronary angiography may be helpful if patient can be adequately stabilized Intraaortic balloon pump is frequently required Once stabilized, early surgery is essential Surgical Without surgical treatment, mortality can reach 80% if acute severe regurgitation Substantial perioperative morbidity and mortality Recent trends for lower operative risk, particularly with associated coronary artery bypass graft SELECTED REFERENCES 1. Hansen AJ et al: Postpartum rupture of the posteromedial papillary muscle. J Card Surg. 27(3):313-6, 2012 2. Fradley MG et al: Rupture of the posteromedial papillary muscle leading to partial flail of the anterior mitral leaflet. Circulation. 123(9):1044-5, 2011 3. Tanimoto T et al: Prevalence and clinical significance of papillary muscle infarction detected by late gadoliniumenhanced magnetic resonance imaging in patients with ST-segment elevation myocardial infarction. Circulation. 122(22):2281-7, 2010 4. Bizzarri F et al: Cardiogenic shock as a complication of acute mitral valve regurgitation following posteromedial papillary muscle infarction in the absence of coronary artery disease. J Cardiothorac Surg. 3:61, 2008 5. Carrillo X et al: Mitral valve repair surgery for traumatic rupture of the anterolateral papillary muscle. Rev Esp Cardiol. 61(12):1360-1, 2008 6. Czarnecki A et al: Acute severe mitral regurgitation: consideration of papillary muscle architecture. Cardiovasc Ultrasound. 6:5, 2008 7. Jayawardena S et al: Anterolateral papillary muscle rupture caused by myocardial infarction: A case report. Cases J. 1(1):172, 2008 8. Russo A et al: Clinical outcome after surgical correction of mitral regurgitation due to papillary muscle rupture. Circulation. 118(15):1528-34, 2008 9. Masci PG et al: Images in cardiovascular medicine. Papillary muscle infarction after cardiopulmonary resuscitation. Circulation. 116(8):e308-9, 2007 10. Sanchez CE et al: Survival from combined left ventricular free wall rupture and papillary muscle rupture complicating acute myocardial infarction. J Am Soc Echocardiogr. 20(7):905, 2007 11. Marangelli V et al: Images in cardiovascular medicine. Three-dimensional imaging in rupture of papillary muscle after acute myocardial infarction. Circulation. 111(23):e385-7, 2005 12. Whiting PC et al: Transesophageal echocardiographic findings in papillary muscle rupture. Anesth Analg. 101(5):1292-3, 2005 13. Morishita S et al: A case of papillary muscle rupture caused by acute myocardial infarction. J Med. 32(5-6):301-9, 2001 14. McQuillan BM et al: Severe mitral regurgitation secondary to partial papillary muscle rupture following myocardial infarction. Rev Cardiovasc Med. 1(1):57-60, 2000 15. Park CW et al: Papillary muscle rupture complicating inferior myocardial infarction in a young woman with systemic lupus erythematosus and antiphospholipid syndrome. Nephrol Dial Transplant. 13(12):3202-4, 1998 16. Weiss SR et al: Isolated acute papillary muscle infarction in the absence of coronary artery disease resulting in cardiogenic shock and emergent mitral valve replacement. Cathet Cardiovasc Diagn. 43(2):185-9, 1998 17. Barbour DJ et al: Rupture of a left ventricular papillary muscle during acute myocardial infarction: analysis of 22 necropsy patients. J Am Coll Cardiol. 8(3):558-65, 1986 P.8:81

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(Left) Transthoracic echocardiogram shows a severely prolapsing posterior mitral valve leaflet into the left atrium . Note the position of the anterior leaflet . Papillary muscle rupture was suspected. (Right) Corresponding color Doppler image shows severe mitral regurgitation during ventricular systole. Regurgitant jet extends to the posterior left atrial wall, consistent with severe regurgitation.

(Left) Corresponding transesophageal echocardiogram during atrial systole shows the posterior mitral valve leaflet in the left ventricle with no discernible papillary muscle attachment . (Right) Corresponding transesophageal echocardiogram during ventricular systole shows severe prolapse of the posterior mitral valve leaflet into the left atrium with no discernible papillary muscle attachment . Note widely regurgitant mitral orifice .

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(Left) Three-chamber coronary CTA shows a severe, posterior leaflet mitral valve prolapse from an infarcted posterior papillary muscle . Note the large mitral regurgitant orifice . (Right) Three-chamber coronary CTA shows marked posterior mitral leaflet prolapse secondary to papillary head rupture in the setting of acute myocardial infarction.

Right Ventricular Infarction Key Facts Terminology Myocardial infarction of portions or all of right ventricular (RV) free walls and inferior septum Usually seen in subgroup of patients with inferior wall myocardial infarction Imaging Electrocardiogram ST-segment elevation in leads V4R, V5R, and V6R Echocardiography RV cavity dilatation Impaired RV free wall motion (hypokinesis, akinesis, or dyskinesis) Reduced RV ejection fraction Distention of inferior vena cava MR findings Delayed hyperenhancement affecting inferior septum and RV inferior and anterior free walls Impaired RV function induced by ischemic injury is readily visible on steady-state free precession cine imaging CT findings Right coronary artery high-grade stenosis/occlusion can be seen on coronary CT Top Differential Diagnoses Pulmonary embolism May also present with chest pain, right heart failure, and clear lungs on chest radiographs Pericarditis with pericardial tamponade Silent cardiac exam Elevated jugular venous pressure Cardiac sarcoidosis May also result in decreased RV function and abnormal enhancement on late gadolinium enhancement MR imaging

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(Left) Graphic shows right ventricular infarction affecting the right ventricular free wall . Note the involvement of the inferoseptal segment of the left ventricle . (Right) Coronal oblique coronary CTA of a patient with right ventricular infarction shows extensive plaque in the proximal segment and total occlusion of the mid and distal segments of the right coronary artery. Note the nonfilling of most of the right ventricular branches.

(Left) Invasive coronary angiogram of a patient with right ventricular infarction shows extensive plaque in the proximal segment and total occlusion of the mid and distal segments of the right coronary artery. Note that only a single proximal right ventricular branch is visualized. (Right) This short-axis CTA image displayed with a narrow window shows an inferior wall subendocardial perfusion defect corresponding to a right coronary artery territory myocardial infarction. P.8:83

TERMINOLOGY Abbreviations Right ventricular myocardial infarction (RVMI) Definitions Myocardial infarction of portions or all of right ventricular (RV) free walls and inferior septum Subgroup of patients with left ventricular (LV) inferior wall infarction have concomitant RV infarction IMAGING General Features Best diagnostic clue Delayed hyperenhancement affecting inferior septum and RV inferior wall on MR imaging Occlusion of right coronary artery (RCA) on imaging Location 724

Diagnostic Imaging Cardiovascular RV infarction usually involves inferior septum and inferior free wall to greater extent than anterior free wall Extent depends on location of culprit lesion LV involvement depends on dominance of circulation Size The more proximal the culprit RCA lesion, the larger the RV infarct More distal stenosis may be counteracted by Collateral coronary arterial supply Thebesian vein supply Morphology Posterior descending artery (usually from RCA) supplies inferior/posterior walls of RV Relative sparing of upper RV anterior free wall due to extensive formation of collateral vessels (including those from left anterior descending [LAD] artery via moderator band) Electrocardiogram ST-segment elevation in leads V4R, V5R, and V6R Strong predictor of RV infarction Radiographic Findings Chest radiography Hypotension in absence of interstitial edema Abnormal cardiac silhouette: RV enlargement is best appreciated on lateral view CT Findings CTA Cardiac CTA sensitivity = 90-97% for detection of hemodynamically significant RCA stenosis using 64-slice or greater CT Multiphasic cine reconstructions provide accurate assessment of RV global/regional function & dilation Ejection fraction and RV volumes can be quantified with volumetric, threshold-based, or modelbased software algorithms MR Findings T2WI T2 hyperintense (bright) areas in acute RVMI MR cine Impaired RV function induced by ischemic injury is readily visible on steady-state free precession cine imaging Diminished RV function is common in patients with inferior myocardial infarction RV function often improves over time RV function can be quantified with excellent reproducibility Cine MR is gold standard Delayed enhancement Late gadolinium enhancement (LGE) MR is more sensitive and specific than ECG, physical examination, or echocardiography for detection of RVMI Gradient-echo inversion-recovery sequence used for LGE MR shows infarcted myocardium as bright and normal myocardium as dark RV inversion time, which has to be selected by operator, is often slightly shorter (20-40 milliseconds) than LV inversion time LGE MR images should be obtained 10-15 minutes post gadolinium administration Very low interobserver variability/excellent reproducibility MR perfusion imaging Reduced perfusion, frequently not visible because of thin walls of RV Echocardiographic Findings Echocardiogram 2D echocardiography Reduced regional &/or global RV function with decreased RV ejection fraction RV dilation Hypoxia: Right-to-left shunt resulting from elevated RV pressure Paradoxical motion of interventricular septum Myocardial performance index (MPI): Sum of isovolumic relaxation and contraction time/ejection fraction MPI > 0.30 suggests RV infarction Doppler 725

Diagnostic Imaging Cardiovascular Tricuspid regurgitation Decrease in systolic velocity is associated with worse prognosis Echocardiography is useful for excluding tamponade and constrictive pericarditis Echocardiography has sensitivity of 82% and specificity of 93% for RV infarction Angiographic Findings Ventricular angiography findings Reduced RV regional wall motion Reduced RV ejection fraction Coronary angiography findings > 90% due to RCA occlusion, with small percentage due to circumflex occlusion in patients with leftdominant circulation To produce RVMI, occlusion is usually proximal to major RV branches RV outflow tract is usually spared as conus artery arises very proximally from RCA or separately from right cusp (30%) P.8:84

Nuclear Medicine Findings Radionuclide angiography findings Reduced RV ejection fraction Regional myocardial dysfunction Imaging Recommendations Best imaging tool LGE cardiac MR: Shows abnormal enhancement of RV Protocol advice Using LGE MR, select inversion time to null signal from RV Many vendors have single-shot variant of LGE MR sequence that can be used with good results even in arrhythmic or uncooperative patients DIFFERENTIAL DIAGNOSIS Pulmonary Embolism May also present with chest pain, right heart failure, and clear lungs on CXR McConnell sign on echocardiography (akinesia of mid-free wall but normal motion of apex) Acute Pericarditis/Tamponade Silent cardiac exam; elevated jugular venous pressure Cardiac Sarcoidosis May also result in decreased RV function and abnormal enhancement on LGE MR imaging Hypertrophic Cardiomyopathy Involves RV in up to 33% PATHOLOGY General Features Etiology RVMI is usually due to atherosclerotic disease affecting RCA RCA is dominant, supplying inferior septum via posterior descending artery in 85-90% of patients RVMI (especially RV apex) can also occur with LAD infarction RV thrombus may develop Ischemia-induced decrease in RV output leads to decreased LV preload This in turn reduces LV output RV infarction results in decreased RV compliance and increased RV diastolic pressures Can lead to RA ischemia and decreased function Can subsequently cause increases in atrial natruretic peptide Rarely, RVMI may be complicated by ventricular septal rupture, resulting in ventricular septal defect (VSD) VSD secondary to myocardial infarction results in acute left-to-right shunt, which further overloads the already impaired RV Also further reduces effective LV preload CLINICAL ISSUES Presentation Most common signs/symptoms Classic triad 726

Diagnostic Imaging Cardiovascular Distended neck veins, normal lungs, & hypotension Chest pain associated with Reduced cardiac output/pump failure Ventricular arrhythmias In RV infarction with unexplained hypoxia, always suspect right-to-left shunt at atrial level Demographics Age Same demographics as LV infarction due to coronary artery disease Epidemiology Isolated RV infarction is very rare and usually occurs in association with inferior LV infarction Transient RV dysfunction is more common than myocardial infarction (MI) Prevalence varies: 10-50% of all inferior wall MI Natural History & Prognosis Patients with RVMI in addition to inferior myocardial infarction have increased morbidity and mortality Significant hypotension is common despite elevated venous pressures Ventricular arrhythmias and atrioventricular conduction abnormalities Bradycardia may develop and require pacing support Patients who survive acute phase usually recover RV function over time Treatment Volume expansion is critical to medical treatment Acute reperfusion; percutaneous intervention or thrombolysis Successful reperfusion is associated with rapid decrease in right atrial pressures Important to decrease right atrial pressure because persistently elevated levels are associated with poorer outcomes DIAGNOSTIC CHECKLIST Consider RVMI in patients presenting with acute chest pain, right heart failure, and hypotension SELECTED REFERENCES 1. Goldstein JA: Acute right ventricular infarction: insights for the interventional era. Curr Probl Cardiol. 37(12):533-57, 2012 2. Kakouros N et al: Right ventricular myocardial infarction: pathophysiology, diagnosis, and management. Postgrad Med J. 86(1022):719-28, 2010 3. Kaandorp TA et al: Assessment of right ventricular infarction with contrast-enhanced magnetic resonance imaging. Coron Artery Dis. 18(1):39-43, 2007 4. Larose E et al: Right ventricular dysfunction assessed by cardiovascular magnetic resonance imaging predicts poor prognosis late after myocardial infarction. J Am Coll Cardiol. 49(8):855-62, 2007 5. Kumar A et al: Contrast-enhanced cardiovascular magnetic resonance imaging of right ventricular infarction. J Am Coll Cardiol. 48(10):1969-76, 2006 6. Mehta SR et al: Impact of right ventricular involvement on mortality and morbidity in patients with inferior myocardial infarction. J Am Coll Cardiol. 37(1):37-43, 2001 P.8:85

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(Left) Short-axis LGE MR shows abnormal enhancement signifying infarction of the inferior left ventricle and inferior septum with extension to the inferior RV . Note that the RV free wall anteriorly demonstrates no evidence of infarction . (Right) Short-axis T2WI MR of an inferoseptal and RV infarction shows abnormal increased signal of the inferior left ventricle and inferior septum with extension to involve the inferior RV , indicating that the myocardial infarction is acute.

(Left) Short-axis LGE MR demonstrates inferior wall infarction extending to the inferior septum/left ventricle and inferior RV wall . Most RV infarctions occur in conjunction with an inferior wall/inferoseptal myocardial infarction. (Right) Short-axis LGE MR demonstrates inferior septal enhancement in a patient with cardiac sarcoidosis. Note also the extensive abnormal enhancement of the RV free wall, a finding not usually seen in cases of RV infarction.

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(Left) Short-axis cine (left) and LGE (right) MR of a patient with hypertrophic cardiomyopathy and RV involvement shows extensive hypertrophy of the distal septum effacing the RV cavity . Abnormal enhancement is noted as well and is predominately seen at sites where the RV inserts on the septum . (Right) Short-axis MR cine shows a large pericardial effusion producing cardiac tamponade. This entity can mimic the clinical picture produced by RV infarction.

Nonatherosclerosis Myocardial Infarction Key Facts Terminology Myocardial infarction unrelated to coronary atherosclerosis Imaging Invasive coronary angiography No evidence of coronary atherosclerosis Regional wall motion abnormalities acutely Coronary CTA (64 slices) has high sensitivity (98%), specificity (88%), and negative predictive value (95-100%) for detection of hemodynamically significant stenosis May see complications of infarction: Left ventricular thrombus CT of lung and mediastinum may provide clue to underlying etiology Late-enhancement MR can demonstrate presence, location, and size of infarction Top Differential Diagnoses Acute aortic dissection Acute myocarditis Pulmonary embolism Takotsubo syndrome Clinical Issues Presents with classic clinical features of atherosclerotic acute myocardial infarction Cardiogenic shock if large area of left ventricle is ischemic Lower prevalence of atherosclerosis risk factors Smoking, cholesterol elevation, diabetes, hypertension, family history, prior angina Treatment Standard therapy for type 1 myocardial infarction Percutaneous coronary intervention/surgery is not generally used except in coronary dissection

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(Left) Late-enhancement cardiac MR in a 23-year-old man shows an extensive left ventricular apical acute myocardial infarction with 100% transmurality. Note additional smaller infarcts within the interventricular septum suggesting possible embolic source. (Right) Corresponding coronary CTA shows entirely normal coronary arteries with no evidence of atherosclerosis. This image shows a curved multiplanar reformat normal left anterior descending (LAD) coronary artery.

(Left) Repeat cardiac MR with black blood FSE in the same patient 2 days later shows a small nodule arising from the posterior wall of the orifice of the left atrial appendage, not identified on the initial cardiac MR. (Right) Surgical resection of the nodule in the same patient confirmed primary cardiac sarcoma . Such tumors are prone to tumor surface thrombus formation. “Check areas” to look for occult cardiac tumors on imaging include the orifices of the pulmonary veins and the atrial appendages. P.8:87

TERMINOLOGY Definitions Myocardial infarction (MI) unrelated to coronary atherosclerosis IMAGING General Features Best diagnostic clue Invasive coronary angiography demonstrates no evidence of coronary atherosclerosis (2.8% prevalence) Location ECG and enzymes similar to typical acute MI Morphology 730

Diagnostic Imaging Cardiovascular Underlying cause often difficult to elucidate Radiographic Findings Chest radiography Acute pulmonary edema is classic complication of cocaine abuse CT Findings CTA Coronary CTA (64 slices) has high sensitivity (98%), specificity (88%), and negative predictive value (95100%) for detection of hemodynamically significant stenosis May see complications of infarction: Left ventricular thrombus Excellent depiction of Kawasaki, coronary vasculitis, and coronary aneurysms CT perfusion 1st-pass perfusion information can be derived from same data set used to visualize coronary arteries Circumferential hypoattenuation on 1st-pass imaging can be secondary to syndrome X (microvascular obstruction) CT viability Requires 2 scans: Conventional CTA followed (after delay of 5-15 minutes) by 2nd scan to identify late contrast hyperenhancement of myocardium Normal myocardium has densely packed myocytes and therefore has little extracellular space In setting of acute MI, loss of membrane integrity increases volume of contrast distribution, leading to hyperenhancement on delayed imaging CT of lung and mediastinum may provide clue to underlying etiology Acute pulmonary edema: Increased ground-glass opacities and septal lines, classically seen in cocaine abuse Aortic and pulmonary wall abnormalities: Thickened in Takayasu arteritis Radiation: Pulmonary fibrosis, fibrosing mediastinitis Pulmonary parenchymal aneurysms: Polyarteritis nodosa Pulmonary embolism in thrombotic states: Systemic lupus erythematosus with antiphospholipid syndrome Chest trauma: Pulmonary contusion, laceration, pneumothorax, fractured ribs MR Findings T2* GRE Can show arterial wall edema in large vessel vasculitis Delayed enhancement Viability Late enhancement can demonstrate presence, location, and size of infarction Perfusion 1st-pass perfusion (stress followed by rest) Hybrid gradient echo-planar sequence acquired during bolus of 0.1 mmol/kg gadolinium Regional wall motion MR is gold standard for chamber volumetrics Standardized 17-segment AHA model utilized Steady-state free precession sequence will show regional wall motion abnormality in infarction MRA For anomalous coronary arteries, especially in young female patients (no radiation) Demonstrates external compression (e.g., by enlarged pulmonary artery in PDA) Echocardiographic Findings Echocardiogram Regional wall motion abnormalities acutely Wall thinning chronically May demonstrate complications of infarction Left ventricular thrombus Angiographic Findings Invasive coronary angiography (ICA) No evidence of coronary atherosclerosis Beware: Many patients with apparently normal ICAs have significant coronary plaque burden with positive remodeling, and most myocardial infarctions arise from lesions causing < 50% luminal narrowing Nuclear Medicine Findings PET 731

Diagnostic Imaging Cardiovascular Currently regarded as gold standard for myocardial viability assessment, with exception of subendocardial infarction detection DIFFERENTIAL DIAGNOSIS Acute Aortic Dissection May dissect down and into coronary artery ostia Acute Myocarditis Prodromal flu-like symptoms, normal invasive angiogram Pulmonary Embolism Pleuritic chest pain, dyspnea, and elevated D-dimers Takotsubo Syndrome “Broken heart” or “stress” cardiomyopathy PATHOLOGY General Features Etiology Coronary vasospasm Cocaine abuse Ethanol abuse P.8:88

Produces concentration-dependent coronary vasospasm in animal studies Cigarette smoking Endothelial dysfunction Calcium channel withdrawal Sorafenib 5-fluorouracil Embolization Rare; common sources include cardiac cavity and appendages, infective endocarditis, prosthetic valves Inflammation/vasculitis Takayasu arteritis: Granulomatous vasculitis that affects large arteries May involve coronary ostia Syphilitic aortitis with ostial narrowing Coxsackie virus B Kawasaki disease Radiation-induced wall thickening Polyarteritis nodosa, systemic lupus erythematosus, giant cell arteritis Thrombosis/hypercoagulability Factor VII activity Factor V Leiden Protein C deficiency Hyperhomocystinuria Excessive estrogens Cigarette smoking Spontaneous coronary dissection Rare but well-described entity occurring particularly in pregnant women Myocardial bridge Clinical significance of myocardial bridge appears to be related to anatomic properties of tunneled segment of coronary artery Chest trauma Percutaneous coronary intervention In-stent restenosis Allergy (Kounis syndrome) Severe anemia Radiation: Usually long latent period; valves and coronary arteries may be damaged CLINICAL ISSUES Presentation Most common signs/symptoms Classic clinical features of atherosclerotic acute MI 732

Diagnostic Imaging Cardiovascular Central, crushing chest pain, radiation to left arm classically Cardiogenic shock if large area of left ventricle is ischemic Other signs/symptoms Atypical pain in jaw, epigastrium Nausea, vomiting, diaphoresis No conduction disturbances Clinical profile Lower prevalence of atherosclerosis risk factors: Smoking, cholesterol elevation, diabetes, hypertension, family history, prior angina Demographics Age Younger patient population with fewer risk factors for atherosclerosis except for cigarette smoking Epidemiology 6% of acute MI patients have normal coronary arteries at autopsy Natural History & Prognosis Mortality rate significantly lower than with atherosclerosis acute MI patients who are high risk or have left main coronary disease Treatment Medical Standard therapy for type 1 MI In cocaine-associated MI, β-blockers should be avoided as this may aggravate coronary constriction In type 2 MI, treatment should be aimed at correction of underlying cause (e.g., anemia); no benefit in commencing usual secondary prevention medications unless evidence of coincident atherosclerotic disease Screening for thrombophilia is recommended for young patients with spontaneous arterial thromboses Interventional Percutaneous coronary intervention/surgery is not generally used except in coronary dissection DIAGNOSTIC CHECKLIST Consider In patients presenting with acute MI with normal coronary angiogram SELECTED REFERENCES 1. Silvanto A et al: Myocardial infarction with normal coronaries: an autopsy perspective. J Clin Pathol. 65(6):512-6, 2012 2. Yurtdaş M et al: A case of coronary spasm with resultant acute myocardial infarction: likely the result of an allergic reaction. Intern Med. 51(16):2161-4, 2012 3. Kim JA et al: Less common causes of disease involving the coronary arteries: MDCT findings. AJR Am J Roentgenol. 197(1):125-30, 2011 4. Budoff MJ et al: Diagnostic performance of 64-multidetector row coronary computed tomographic angiography for evaluation of coronary artery stenosis in individuals without known coronary artery disease: results from the prospective multicenter ACCURACY trial. J Am Coll Cardiol. 52(21):1724-32, 2008 5. Kardasz I et al: Myocardial infarction with normal coronary arteries: a conundrum with multiple aetiologies and variable prognosis: an update. J Intern Med. 261(4):330-48, 2007 6. Thygesen K et al: Universal definition of myocardial infarction. Circulation. 116(22):2634-53, 2007 7. Larsen AI et al: Characteristics and outcomes of patients with acute myocardial infarction and angiographically normal coronary arteries. Am J Cardiol. 95(2):261-3, 2005 8. Villines TC et al: Diffuse nonatherosclerotic coronary aneurysms: an unusual cause of sudden death in a young male and a literature review. Cardiol Rev. 13(6):309-11, 2005 9. Caussin C et al: Coronary plaque burden detected by multislice computed tomography after acute myocardial infarction with near-normal coronary arteries by angiography. Am J Cardiol. 92(7):849-52, 2003 10. Pinney SP et al: Myocardial infarction in patients with normal coronary arteries: proposed pathogenesis and predisposing risk factors. J Thromb Thrombolysis. 11(1):11-7, 2001 P.8:89

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Diagnostic Imaging Cardiovascular

(Left) Late-enhancement cardiac MR in a 33-year-old woman shows transmural left ventricular anteroseptal infarct in the LAD territory. A small area of microvascular obstruction is noted. (Right) Corresponding invasive coronary angiogram shows a normal LAD. The patient was subsequently diagnosed with systemic lupus erythematosus (SLE). Acute coronary syndromes in SLE are secondary to coronary vasculitis, thrombosis, or embolism (Libman-Sacks endocarditis).

(Left) Coronary CTA shows extensive LAD calcified plaque in a 42-year-old man who had previously received mantle mediastinal radiotherapy for Hodgkin lymphoma. Inset shows heavily calcified aortic valve cusps. Radiation injury to the coronary arteries and valves may be latent and present many years later. (Right) Short-axis cardiac CT shows wall thinning in the left ventricular mid anteroseptal segment, consistent with a chronic myocardial infarction. The patient required TAVI and CABG.

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(Left) Invasive angiogram shows an acute thrombus in the proximal segment LAD. Note the absence of atherosclerosis in the left circumflex artery (LCX) . The patient underwent percutaneous coronary intervention (PCI) and stenting of the LAD lesion. (Right) Corresponding same-day post-procedure cardiac MR demonstrates PCIrelated myocardial infarction in multiple vascular territories, mostly in the LCX territory but also in the interventricular septum in the LAD vascular territory.

Nontransmural Myocardial Infarction Key Facts Terminology Infarct affecting subendocardium with < 100% transmural extension Imaging Function may be normal if infarct is remote and only small portion of transmurality is affected Differentiation of acute vs. old myocardial infarction by CT Values of Hounsfield units may be negative in old infarcts due to fatty metaplasia Left ventricular thinning and calcifications may be present in old myocardial infarction Late gadolinium enhancement (LGE) MR shows hyperenhancement only in inner border (i.e., subendocardium) of left ventricular myocardium LGE MR is the current gold standard for detection and quantification of nontransmural infarct Combined stress-perfusion and LGE MR may differentiate between inducible ischemia and infarcted myocardium Myocardial viability depends on degree of transmurality > 50% transmurality of LGE → poor chance of functional segmental recovery following revascularization = nonviable myocardium < 50% transmurality of LGE → good chance of functional segmental recovery following revascularization = viable myocardium Top Differential Diagnoses Myocarditis (LGE MR helps differentiate from myocardial infarction) Acute myocarditis causes LGE in left ventricular subepicardium (rather than subendocardium) Acute myocarditis causes patchy LGE that does not correspond to vascular distribution

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(Left) Short-axis 1st-pass myocardial perfusion MR shows subendocardial hypoperfusion in the inferior wall of the left ventricle corresponding to the right coronary artery territory. (Right) Short-axis late gadolinium enhancement image from the same patient shows subendocardial enhancement matching the perfusion deficit. The degree of wall enhancement measures > 50%, suggesting a low likelihood of functional segmental recovery following revascularization.

(Left) Short-axis cardiac CTA image with color overlay map shows decreased myocardial perfusion in the lateral wall of the left ventricle corresponding to the left circumflex coronary artery territory. (Right) Axial CTA image from the same patient shows subendocardial hypoperfusion in the lateral left ventricular wall. At coronary catheterization, an occluded obtuse marginal artery was treated with angioplasty and stent. P.8:91

TERMINOLOGY Definitions Infarct affecting subendocardial surface of myocardium with < 100% transmural extension IMAGING General Features Morphology Typically associated with non-Q wave infarction Ischemic necrosis is limited to subendocardium Extent of necrosis is variable Most notable ECG change: Persistent ST segment depression Diminished perfusion and function in affected area 736

Diagnostic Imaging Cardiovascular Functional impairment is limited if minimal thickness is involved Function may be normal if infarct is remote and affects only a small portion of myocardium CT Findings Cardiac gated CTA Cine images may demonstrate regional wall motion abnormality Coronary CTA May demonstrate matching occlusion or high-grade coronary stenosis Cardiac CT myocardial perfusion analysis Reveals subendocardial hypoenhancement consistent with myocardial infarction CT perfusion Underestimates infarct size as compared with late gadolinium enhancement (LGE) MR Delayed-enhancement CT May be feasible but displays poor contrast to noise ratio as compared with MR CT differentiates acute vs. old myocardial infarction Values of Hounsfield units may be negative in old infarction due to fatty metaplasia Left ventricular thinning and calcifications may be present in old myocardial infarction Left ventricular remodeling with left ventricular cavity dilation appears in large, old infarcts MR Findings T2WI May show increased signal intensity representing myocardial edema if infarct is acute Edema typically involves larger area than infarcted myocardium Cine MR Shows regional wall motion abnormality or reduced systolic thickening 1st-pass perfusion MR Shows perfusion defect due to reduced wash-in of gadolinium LGE MR Current gold standard for detection and quantification of nontransmural infarct Shows hyperenhancement only in the inner border (subendocardium) of left ventricular myocardium High-resolution images enable clear differentiation between transmural and nontransmural infarcts Myocardial viability depends on degree of LGE transmurality > 50% → low likelihood of functional segmental recovery after revascularization = nonviable myocardium < 50% → high likelihood of functional segmental recovery after revascularization = viable myocardium Combination of stress-perfusion and LGE MR may allow Differentiation between inducible ischemia and infarcted myocardium Detection of peri-infarct ischemia Echocardiographic Findings Echocardiogram Reduced regional function Not as sensitive as MR for detection of subtle regional wall motion abnormalities Angiographic Findings Left ventriculogram may show regional wall motion abnormality Coronary angiography findings Most commonly, tightly stenosed coronary artery rather than occlusion Tight stenoses that become occluded are more likely to cause nontransmural infarct than mild stenoses that occlude Chronic flow reduction may stimulate collateral formation Nuclear Medicine Findings Radionuclide angiography finding Reduced regional function Cardiac scintigraphy findings Reduced tracer uptake is demonstrated by using perfusion marker Imaging may show thinning or partial thickness perfusion However, usually apparent as wall thinning rather than dropout Nuclear scintigraphy misses ˜ 50% of all small nontransmural subendocardial infarcts Infarct detection may be compromised by partial volume effects DIFFERENTIAL DIAGNOSIS Myocarditis 737

Diagnostic Imaging Cardiovascular May present similar to nontransmural infarct Serum markers and wall motion assessment cannot adequately differentiate myocarditis from infarction Coronary angiography is essential for ruling out myocardial infarction LGE MR helps differentiate myocardial infarction from myocarditis Acute myocarditis affects left ventricular subepicardium rather than left ventricular subendocardium Acute myocarditis causes patchy LGE that does not follow a vascular distribution Transmural Myocardial Infarction Infarct involves entire myocardial thickness P.8:92

Chronic infarct with LGE transmural thickness ≥ 50% is unlikely to have segmental functional recovery following revascularization Associated with poor prognosis and more complications (e.g., lower left ventricular ejection fraction, more ventricular remodeling, etc.) Ischemia Coronary artery stenosis may lead to subendocardial ischemia in absence of infarct. Rest ischemia can be seen in critical stenoses (99%), but otherwise (70%-98%) ischemia will be present only on exercise or pharmacological stress imaging Appears as reversible subendocardial hypoperfusion on stress imaging Endomyocardial Fibrosis Fibrosis of endocardium (not subendocardium) on LGE May show apical obliteration of cavity and involve > 1 coronary territory May have tethering and fibrosis of valve apparatus leading to eccentric atrioventricular valve regurgitation PATHOLOGY General Features Myocardial necrosis Coagulation necrosis Contraction band necrosis Intramyocardial hemorrhage Vascular occlusion Result of early reperfusion before wave front of infarction can extend transmurally CLINICAL ISSUES Presentation Chest pain; clinical picture of acute myocardial infarction May be silent or unrecognized = “missed myocardial infarction” Clinically determined by absence of Q wave on ECG, with serum marker of myocardial infarction and appropriate clinical presentation Poor discrimination from transmural myocardial infarction More commonly seen without ST elevation on presentation ECG Natural history of myocardial infarction is not predictable based on presenting ECG Confirmed by detection of serum markers May result from early reperfusion that prevents transmural extension Thrombolysis Percutaneous intervention Similarly to transmural myocardial infarction, may be associated with malignant arrhythmias Wall thickening may be maintained Result of varied orientation of myofibrils with wall thickness Loss of oblique subendocardial fibers will not necessarily cause loss of normal thickening Treatment Acute percutaneous intervention to restore flow Best done within 1st 3 hours Optimally done with stent implantation and antiplatelet therapy with Gp IIb/IIIa inhibitor Thrombolysis or early mechanical reperfusion can prevent progression to transmural infarct and salvage “at risk” myocardium Early reperfusion may prevent infarction Medical therapy after acute phase Prognosis depends on extent of infarction and degree and location of coronary disease Nontransmural infarcts associated with 738

Diagnostic Imaging Cardiovascular Better prognosis Less infarct expansion Lower risk of cardiac rupture than transmural infarct Mural thrombus Left ventricular aneurysm DIAGNOSTIC CHECKLIST Consider Location, size, and transmural extent of infarct LGE MR: Best technique to assess nontransmural subendocardial infarcts Image Interpretation Pearls Main differentials are transmural myocardial infarction and myocarditis Combination of T2WI and LGE MR help with Differentiation of acute and chronic infarcts Determination of area at risk in acute events SELECTED REFERENCES 1. Ordovas KG et al: Delayed contrast enhancement on MR images of myocardium: past, present, future. Radiology. 261(2):358-74, 2011 2. Ibrahim T et al: Diagnostic value of contrast-enhanced magnetic resonance imaging and single-photon emission computed tomography for detection of myocardial necrosis early after acute myocardial infarction. J Am Coll Cardiol. 49(2):208-16, 2007 3. Stork A et al: Value of T2-weighted, first-pass and delayed enhancement, and cine CMR to differentiate between acute and chronic myocardial infarction. Eur Radiol. 17(3):610-7, 2007 4. Cury RC et al: Diagnostic performance of stress perfusion and delayed-enhancement MR imaging in patients with coronary artery disease. Radiology. 240(1):39-45, 2006 5. Nieman K et al: Differentiation of recent and chronic myocardial infarction by cardiac computed tomography. Am J Cardiol. 98(3):303-8, 2006 6. Ibrahim T et al: Quantitative measurement of infarct size by contrast-enhanced magnetic resonance imaging early after acute myocardial infarction: comparison with single-photon emission tomography using Tc99m-sestamibi. J Am Coll Cardiol. 45(4):544-52, 2005 7. Wagner A et al: Contrast-enhanced MRI and routine single photon emission computed tomography (SPECT) perfusion imaging for detection of subendocardial myocardial infarcts: an imaging study. Lancet. 361(9355):374-9, 2003 8. Choi KM et al: Transmural extent of acute myocardial infarction predicts long-term improvement in contractile function. Circulation. 104(10):1101-7, 2001 9. Reimer KA et al: The “wavefront phenomenon” of myocardial ischemic cell death. II. Transmural progression of necrosis within the framework of ischemic bed size (myocardium at risk) and collateral flow. Lab Invest. 40(6):633-44, 1979 P.8:93

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Diagnostic Imaging Cardiovascular (Left) Short-axis late gadolinium enhancement MR shows subendocardial enhancement in the lateral wall of the left ventricle. The transmurality of the enhancement is ˜ 50%, suggesting a fair probability of functional segmental recovery following revascularization. (Right) Short-axis late gadolinium enhancement MR shows > 50% subendocardial enhancement in the left ventricular septum. There is nonenhancing myocardium that represents no reflow or microvascular obstruction.

(Left) Short-axis 1st-pass myocardial perfusion MR shows subendocardial hypoperfusion in the lateral wall of the left ventricle corresponding to the left circumflex coronary artery territory. The differential for this includes a severe coronary artery stenosis with rest ischemia or a nontransmural myocardial infarction. (Right) Axial cardiac CT shows fatty infiltration in the left ventricular apex and septum from remote myocardial infarction.

(Left) Short-axis late gadolinium enhancement MR shows subendocardial enhancement involving the inferior and inferoseptal walls. Because the transmurality of enhancement is > 50%, there is low likelihood of functional segmental recovery following revascularization. (Right) Two-chamber SSFP MR shows apical wall thinning from remote myocardial infarction. The adjacent low-intensity filling defect represents thrombus , a recognized complication of left ventricular infarction. P.8:94

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(Left) FSE STIR MR shows increased T2 signal in the inferior left ventricular wall due to edema from acute myocardial infarction. Cine SSFP MR (not shown) showed poor contractility in this left ventricular segment. (Right) Short-axis late gadolinium enhancement image from the same patient shows subendocardial enhancement in the inferior wall at the midventricular level (right coronary artery distribution). The degree of enhancement affects ˜ 50% of the myocardium.

(Left) Right anterior oblique coronary angiography image from the same patient shows abrupt cutoff of the distal right coronary artery . (Right) Axial cardiac CT demonstrates normal wall thickness with a subendocardial lowattenuation perfusion defect in a patient with an acute myocardial infarction affecting the left anterior descending coronary artery.

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(Left) Four-chamber SSFP image obtained during end systole shows hypokinesis and lack of wall thickening of the apical septum . (Right) Four-chamber late gadolinium enhancement image from the same patient shows subendocardial enhancement in the apical septum . Note that the area of LGE may have similar signal intensity as blood pool. Correlation with SSFP or FSE images in the same plane may be needed to determine the true endocardial border. P.8:95

(Left) Short-axis coronary CTA image obtained at the mid left ventricular cavity shows subendocardial hypoperfusion involving predominantly the anterior wall extending into the anteroseptal and anterolateral segments. There is a moderate stenosis of the left anterior descending coronary artery . (Right) Axial oblique coronary CTA image from the same patient shows a partially calcified plaque causing severe stenosis in the left anterior descending coronary artery.

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(Left) Paraseptal long-axis maximum-intensity projection image from the same patient demonstrates that the hypoperfusion mirrors the course of the left anterior descending coronary artery. There is a multifocal partially calcified plaque causing severe stenosis . (Right) Left anterior oblique catheter angiography after injection of the left main coronary artery in the same patient confirms left anterior descending artery stenosis in both the proximal and the mid segments. Note normal left circumflex artery .

(Left) Short-axis coronary CTA image obtained at the apical level demonstrates a large subendocardial rest perfusion defect involving the anterior wall of the left ventricle corresponding to the left anterior descending coronary artery territory. Note normal thickness of myocardium in diastole. (Right) Axial oblique image from the same patient demonstrates complete occlusion of the proximal left anterior descending coronary artery . The distal vessel filled via collaterals (not shown).

Post-Infarction LV Aneurysm Key Facts Terminology Akinetic or dyskinetic segment of well-demarcated, thin, scarred myocardium resulting from transmural myocardial infarction Imaging Chest radiography Enlarged cardiac silhouette Nonenhanced CT Linear calcifications of infarcted myocardial wall (in chronic infarction) Contrast-enhanced CT 743

Diagnostic Imaging Cardiovascular Thinned and scarred myocardium Left ventricular apical filling defect consistent with mural thrombus CT angiography Severe coronary artery disease SSFP cine Left ventricular aneurysm with wall thinning and motion abnormality Late gadolinium enhancement MR Transmural scar 1st-pass perfusion Frequently, associated thrombus (nonenhancing mural mass) Echocardiographic findings Excellent method to detect aneurysm Spontaneous echo contrast (smoke) suggests slow flow in aneurysm and increased likelihood for thrombus formation Top Differential Diagnoses Pseudoaneurysm Acute or subendocardial myocardial infarction Hibernating myocardium Sarcoidosis Takotsubo cardiomyopathy

(Left) Graphic shows a mid to apical anterolateral wall aneurysm . Note thinning and fibrosis of the myocardium and outward bulge. A mural thrombus is layered against the aneurysm wall. (Right) Three-chamber view transthoracic echocardiogram shows that an apical infarction in this patient has resulted in formation of an aneurysm. Note the outward bulge of the apex on this diastolic image.

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(Left) PA radiograph shows circumscribed curvilinear calcification at the cardiac apex corresponding to the expected location of the left ventricle (LV). This represents a left anterior descending (LAD) coronary artery territory LV true aneurysm. (Right) Two-chamber LGE MR shows transmural late enhancement of the thinned, ballooned anterior and apical myocardium signifying extensive scar. There is a large nonenhancing thrombus at the apex . MR is 2× as sensitive as echo for detecting thrombus. P.8:97

TERMINOLOGY Definitions Akinetic or dyskinetic segment of well-demarcated thin, scarred, and fibrotic myocardium resulting from healed transmural myocardial infarction (MI) IMAGING General Features Best diagnostic clue Focal contour bulge of the LV present in diastole that worsens in systole (dyskinesia) on cine imaging (MR, echography, angiography, gated CT) Morphology Differentiated into true and false aneurysms (pseudoaneurysms) True aneurysms have residual layer of myocardium present Most often involve anterior wall and apex (left anterior descending [LAD] coronary artery territory) Opening or mouth of aneurysm is as wide or wider than periphery Rarely rupture False aneurysms (pseudoaneurysms) represent contained ruptures of myocardium held together by pericardium/pericardial adhesions Most often involve inferobasal or inferolateral walls Opening or mouth of aneurysm is smaller than periphery (reflecting its nature as a contained rupture) Have significant risk of rupture with tamponade Radiographic Findings Radiography Enlarged cardiac silhouette Occasionally can identify aneurysm as definable outpouching Aneurysm-associated calcifications may be visible on frontal and lateral CXR Curvilinear calcifications confined to left ventricle (LV) If calcifications extend beyond LV, they are likely pericardial calcifications CT Findings NECT Aneurysmal remodeling of LV and calcifications of infarcted myocardial wall (only in chronic MI) Mural thrombus may calcify 745

Diagnostic Imaging Cardiovascular CECT Thinned and scarred myocardium is easily detected Frequently accompanied by LV apical filling defect consistent with mural thrombus CTA Coronary CTA usually shows > 70% stenosis (often total occlusion) of artery supplying aneurysmal segment Dyskinesia is apparent on multiphase ECG-gated (cine) reconstruction MR Findings SSFP cine LV aneurysm is visible as an area of wall thinning and dyskinesia Accurately quantifies LV volumes, mass, and wall thickness Delayed enhancement Transmural delayed enhancement of aneurysm wall secondary to scar/fibrosis Such segments are not viable and will not recover function if revascularized Will demonstrate any associated thrombus as intracavitary focus of low signal intensity Thrombi are often attached to areas of transmural late enhancement (infarct) Most easily visualized using late gadolinium enhancement (LGE) MR with long inversion time (˜ 600 milliseconds) 1st-pass perfusion Aneurysm with perfusion defect secondary to coronary artery occlusion Thrombus can be detected as nonenhancing mural mass Echocardiographic Findings Echocardiogram Excellent method to identify aneurysm and wall motion abnormalities Can demonstrate thrombus in aneurysm Less sensitive than contrast-enhanced MR for thrombus detection (misses ˜ 50% of thrombi found on MR), particularly apical thrombus Spontaneous echo contrast (“smoke”) within aneurysm suggests slow flow and increased likelihood for thrombus formation Angiographic Findings Coronary angiogram will usually show occlusion of infarct-related artery Typically few or absent collaterals Left ventriculogram Detects wall motion abnormality in aneurysmal segment May detect thrombi as filling defects but is much less sensitive than MR Nuclear Medicine Findings Radionuclide scintigraphy findings Fixed perfusion defect in aneurysmal segment with abnormal wall motion DIFFERENTIAL DIAGNOSIS Pseudoaneurysm Contained rupture of myocardium lacking myocardial wall Narrow neck with wider base along retaining pericardial surface Typically basal inferior or lateral LV segments Acute or Subendocardial Myocardial Infarction Akinesis or hypokinesis without aneurysm Also shows abnormal enhancement on LGE MR LGE MR of acute transmural MIs may show no-reflow zone of absent enhancement in core of infarct P.8:98

Hibernating Myocardium Chronically ischemic myocardium may become thinned and dyskinetic yet remain viable Will show minimal (< 50%) or no hyperenhancement on LGE MR imaging Sarcoidosis Coalescent granulomas can result in aneurysm formation Tends to involve inferolateral wall at basal level Takotsubo Cardiomyopathy Hallmarks are absence of coronary artery disease and recovery of wall motion Appear normal on LGE MR 746

Diagnostic Imaging Cardiovascular May show T2 edema Chagas Disease Apical aneurysm (vortex lesion) is classic lesion of advanced disease PATHOLOGY General Features Transmural infarct 70-85% located in anterior and apical walls due to LAD occlusion and lack of collaterals 10-15% involve inferobasal walls due to right coronary artery occlusion Size can vary; generally 1-8 cm in diameter Microscopic Features Early phase demonstrates coagulative myocardial necrosis with inflammation Gradual replacement with scar tissue (fibrosis) Border zone between aneurysm and normal myocardium has patchy fibrosis and abnormal myocardial fiber arrangement Potential for arrhythmogenic substrate CLINICAL ISSUES Presentation Most common signs/symptoms History of MI is virtually always present Persistent ST elevation after MI Frequently asymptomatic Other signs/symptoms Cardiac enlargement with diffuse dyskinetic apical impulse Extra heart sounds (S3 and S4) from blood flow into a dilated, stiffened cavity Mitral regurgitation due to altered ventricular geometry Clinical profile Heart failure and angina Systolic bulging of aneurysm “steals” part of LV stroke volume Leads to reduction in cardiac output, which triggers further adverse remodeling Ventricular arrhythmias 2 mechanisms for arrhythmias and sudden cardiac death Further myocardial ischemia leading to ventricular tachycardia or fibrillation Reentrant tachycardias from border zone Systemic embolization of intracardiac thrombus Ventricular rupture is rare with true aneurysms Demographics Epidemiology Incidence is ˜ 8-15% in patients who present with ST elevation MI Recent improvements in revascularizations and post-MI medical therapy have minimized the development of LV aneurysms Natural History & Prognosis Natural history of LV aneurysms is unclear Presence of aneurysm indicates poor prognosis 6× higher mortality than in post-infarction patients without aneurysms Treatment Medical therapy Afterload reduction with ACE inhibitors Heart rate and blood pressure control with β-blockers Anticoagulation with warfarin After large anterior MI with significant LV dysfunction Documented thrombus in aneurysm Surgical therapy: Aneurysmectomy ACC/AHA class IIa recommendation in patients with LV aneurysm with intractable ventricular arrhythmias &/or heart failure despite catheter-based or medical therapy Systemic embolization in patients who cannot take warfarin Catheter-based therapy Endocardial mapping with endocardial resection/ablation can be performed to control intractable ventricular arrhythmias in border zones DIAGNOSTIC CHECKLIST 747

Diagnostic Imaging Cardiovascular Consider LV aneurysms in all patients with transmural MI and LV dilation and systolic dysfunction SELECTED REFERENCES 1. Amin FR et al: Ventricular septal rupture and intraseptal pseudo-aneurysm complicating acute myocardial infarction: management in the multimodality imaging era. Postgrad Med J. 88(1041):425-6, 2012 2. Shriki JE et al: Incidental myocardial infarct on conventional nongated CT: a review of the spectrum of findings with gated CT and cardiac MRI correlation. AJR Am J Roentgenol. 198(3):496-504, 2012 3. Heatlie GJ et al: Left ventricular aneurysm: comprehensive assessment of morphology, structure and thrombus using cardiovascular magnetic resonance. Clin Radiol. 60(6):687-92, 2005 4. Konen E et al: True versus false left ventricular aneurysm: differentiation with MR imaging—initial experience. Radiology. 236(1):65-70, 2005 5. HA JW et al: Left ventricular aneurysm after myocardial infarction. Clin Cardiol. 21(12):917, 1998 6. Meizlish JL et al: Functional left ventricular aneurysm formation after acute anterior transmural myocardial infarction. Incidence, natural history, and prognostic implications. N Engl J Med. 311(16):1001-6, 1984 P.8:99

Image Gallery

(Left) Left anterior oblique 3D reconstruction of a coronary CTA shows extensive calcification and occlusion of the proximal LAD, which has resulted in a large apical aneurysm. Note the broad-based outpouching of the aneurysm , which has the location and morphology associated with true aneurysms. (Right) Vertical long-axis (2-chamber) coronary CTA shows occlusion of the proximal LAD and apical aneurysm with thinned myocardium and subendocardial hypoattenuation .

(Left) Left ventriculogram of a pseudoaneurysm (confirmed on later MR imaging) shows an aneurysm along the 748

Diagnostic Imaging Cardiovascular posterior LV margin . In this location, a false aneurysm should be considered. (Right) Four-chamber cine MR of a false aneurysm shows a focal area of myocardial discontinuity along the basal to mid anterolateral segments with only pericardium as the retaining structure. This illustrates the nature of a pseudoaneurysm as a contained rupture of the myocardium.

(Left) Vertical long-axis (2-chamber) MR cine images before (left) and after (right) contrast show a mural thrombus lining an anterior wall aneurysm. It is not seen on the precontrast image as the thrombus is isointense to myocardium. (Right) Horizontal long-axis (4-chamber) MR cine (top) and LGE (bottom) images of a patient with sarcoidosis show aneurysm formation of the basal inferolateral wall. Note that the area of outpouching exhibits abnormal enhancement on the LGE image.

Post-Infarction LV Pseudoaneurysm Key Facts Terminology Rupture of left ventricular wall contained by epicardium or pericardium Discontinuation of left ventricular endocardium and myocardium in pseudoaneurysm, whereas true aneurysm has intact wall Imaging Visualization of morphology on echocardiography, MR, CT, and left ventriculography Typically, there is area of dyskinesis (outward movement in systole) Neck is often narrower than aneurysmal sack Difficult to differentiate from true aneurysm Discontinuation of myocardium can sometimes be detected on CT, MR, and echocardiography Thrombi may be present Top Differential Diagnoses True aneurysm Diverticulum Other fluid-filled structures (e.g., pericardial cyst) Clinical Issues Myocardial infarction is most frequent cause Valvular surgery, especially mitral valve surgery, is 2nd most frequent cause Pseudoaneurysms may occur in apical region after transapical aortic valve replacement High rate of spontaneous rupture Clinically silent course is possible Only 3% present as sudden death Surgery is associated with high risk Conservative treatment should be considered

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(Left) Contrast-enhanced CTA (5-chamber view) shows a small left ventricular pseudoaneurysm in the posterolateral wall. The neck of pseudoaneurysms is typically narrower than the aneurysmal sac, but it is usually not possible to unambiguously differentiate pseudoaneurysms from true aneurysms of the left ventricle. (Right) Short-axis view of the left ventricle shows the same pseudoaneurysm. Most often, left ventricular pseudoaneurysms are a consequence of myocardial infarction.

(Left) Left ventricular pseudoaneurysms can also be the consequence of cardiac surgery, especially mitral valve replacement, as seen in this example of a pseudoaneurysm in the inferior wall secondary to mechanical mitral valve replacement. Note mitral valve prosthesis . (Right) Short-axis view contrast-enhanced CT clearly shows the narrow neck of the pseudoaneurysm . The walls of the pseudoaneurysm are partly calcified. P.8:101

TERMINOLOGY Definitions Rupture contained by epicardium or pericardium Unlike true aneurysm, which has intact wall, pseudoaneurysm has discontinuation of left ventricular endocardium and myocardium IMAGING General Features Size Average diameter: 6 cm Average neck width: 2 cm Angiographic Findings 750

Diagnostic Imaging Cardiovascular Conventional Left ventriculogram reveals an area of dyskinesis (outward movement in systole), often with a neck that is narrower than the pseudoaneurysm Differentiation from true aneurysm is difficult Echocardiographic Findings Echocardiogram Directly visualizes pseudoaneurysm Dyskinetic area Discontinuation of ventricular wall may be appreciable Often but not always with a narrow neck True aneurysms are generally same size at neck and at maximal diameter Color Doppler Hallmark Doppler finding is bidirectional flow into and out of pseudoaneurysm (to-and-fro murmur) Since a true left ventricular aneurysm is part of left ventricle, there is no characteristic Doppler finding MR Findings SSFP cine Measures dimensions of pseudoaneurysm May demonstrate small pericardial effusion Delayed enhancement Good technique to assess for residual thin layer of fibrotic myocardium May be confused with enhancement of inflamed pericardium CT Findings Cardiac gated CTA Visualizes pseudoaneurysm Often demonstrates a neck that is narrower than the pseudoaneurysm Abrupt discontinuation of ventricular wall may be appreciable May demonstrate small pericardial effusion Imaging Recommendations Best imaging tool Cardiac MR Protocol advice Cine, perfusion, and delayed enhancement DIFFERENTIAL DIAGNOSIS True Aneurysm All 3 layers of myocardium are intact and form aneurysm wall Differentiation between pseudoaneurysm and true aneurysm may be very difficult or impossible Diverticulum Intact muscular layer Pericardial Cyst Fluid-filled structure outside myocardial wall PATHOLOGY General Features Etiology Postmyocardial infarction is most likely Inferior wall and lateral wall infarctions lead to pseudoaneurysms 2× as often as anterior infarcts Cardiac surgery is 2nd most common cause of pseudoaneurysm Most likely culprit surgeries are mitral valve replacement and aneurysmectomy Pseudoaneurysms may occur in apical region after transapical aortic valve replacement Trauma accounts for ˜ 7% of cases CLINICAL ISSUES Presentation Most common signs/symptoms Often clinically silent (asymptomatic) Chest pain and dyspnea in case of impaired left ventricular function Syncope can occur Stroke may be caused by thrombi in pseudoaneurysm To-and-fro murmur may be detectable in up to 2/3 of patients Often accompanied by ST-segment elevation on ECG 751

Diagnostic Imaging Cardiovascular Natural History & Prognosis 30-45% of untreated pseudoaneurysms result in rupture Treatment Prompt surgical intervention Treatment may be conservative if operative risk is considered high and pseudoaneurysm has been stable over long time period SELECTED REFERENCES 1. Frances C et al: Left ventricular pseudoaneurysm. J Am Coll Cardiol. 32(3):557-61, 1998 2. Komeda M et al: Surgical treatment of postinfarction false aneurysm of the left ventricle. J Thorac Cardiovasc Surg. 106(6):1189-91, 1993 3. Bolooki H: Surgical treatment of complications of acute myocardial infarction. JAMA. 263(9):1237-40, 1990 4. Dachman AH et al: Left ventricular pseudoaneurysm. Its recognition and significance. JAMA. 246(17):1951-3, 1981 P.8:102

Image Gallery

(Left) CECT shows a large inferior left ventricular pseudoaneurysm secondary to a myocardial infarction. The rim of healthy myocardium and the fact that the neck is narrower that the aneurysmal sac are clearly demonstrated. This makes pseudoaneurysm highly likely, but it is not an absolute proof. (Right) Short-axis view CECT in the same patient clearly demonstrates the rim of healthy myocardium at the neck of the aneurysmal sac , which suggests a pseudoaneurysm rather than a true aneurysm.

(Left) Cardiac CECT (2-chamber view) shows a pseudoaneurysm of the inferobasal wall complicating mitral valve surgery. The narrow neck of the pseudoaneurysm and the rim of myocardial tissue are clearly seen. Small metallic 752

Diagnostic Imaging Cardiovascular structures represent cross sections of the mitral valve prosthesis . (Right) CECT (3-chamber view; same patient) shows the pseudoaneurysm with calcification . Along with the mitral valve, the aortic valve has also been replaced by a bioprosthesis.

(Left) Image orientation and anatomic circumstances can create the impression of a narrow neck, making it an unreliable criterion to differentiate pseudoaneurysms from true aneurysms, in which the entry is presumably the widest point. Here, the entry appears narrower than the aneurysmal sac due to submitral apparatus (papillary muscle and chordae). (Right) MinIP (10 mm thickness; same patient) clearly shows that the impression of a narrow neck is caused by the papillary muscle . P.8:103

(Left) Left ventriculography shows aneurysmal bulging at the inferior side of the left ventricular apex. The presence of a narrow neck makes a pseudoaneurysm possible, but it cannot be definitely proven. Analysis in motion would typically show outward-directed movement during systole. (Right) Echocardiogram shows a large inferobasal pseudoaneurysm with a neck that is narrower than the diameter of the aneurysm.

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(Left) Graphic shows a left ventricular pseudoaneurysm in the inferolateral wall. Note that the neck is much narrower than the pseudoaneurysm diameter. Pseudoaneurysms are ventricular free wall ruptures contained by fused epi and pericardial layers. (Right) Short-axis LGE MR shows a typical pseudoaneurysm in the inferolateral wall with thin layer of delayed hyperenhancement and mural thrombus . Note transmural LGE due to a large inferolateral left ventricular infarct.

(Left) MR cine (4-chamber view) shows a rare case of a left ventricular apical pseudoaneurysm contained by the pericardium. This location rarely harbors pseudoaneurysms but is frequently affected by true aneurysms. (Right) MR perfusion (2-chamber view) shows gadolinium filling the apical pseudoaneurysm . There are also perfusion defects in the anterior and inferior apical left ventricular walls.

Post-Infarction Mitral Regurgitation Key Facts Terminology Ischemic mitral regurgitation (IMR) is a common complication of myocardial infarction and may develop in acute or chronic phase Imaging Echocardiography is clinical gold standard Effective regurgitant orifice area (EROA) can be assessed by several methods 3D echo is superior to 2D transthoracic echocardiography Cardiac CT EROA correlates well with echocardiography grading Advantage over echocardiography: Can depict obstructive coronary artery disease 754

Diagnostic Imaging Cardiovascular Cardiac MR Steady-state free precession bright blood sequence shows mitral regurgitant jet Mitral regurgitant volume is quantified by subtracting aortic flow volume from left ventricular stroke volume Late enhancement can demonstrate presence, location, and size of infarction Top Differential Diagnoses Other causes of mitral regurgitation Clinical Issues Acute IMR is characterized by acute pulmonary edema, cardiogenic shock; chronic IMR is characterized by progressive heart failure Therapies include ACE inhibitors or angiotensin receptor blockers, β-blockers, mineralocorticoid receptor blockers, and diuretics Surgery in patients referred for coronary bypass Annuloplasty in those with annular dilation Reimplantation of pap muscle in selected patients

(Left) Axial coronary CTA shows a widely patent left main coronary and proximal segment of left anterior descending (LAD) coronary artery and an occlusive lesion in the mid segment of LAD. (Right) Corresponding coronary CTA short-axis view in end-diastole shows wall thinning in the left ventricular mid anteroseptal segment, consistent with a chronic myocardial infarction in the LAD vascular territory. A circumflex territory infarct is also present .

(Left) Cardiac CT multiphasic reconstruction in ventricular systole shows incomplete coaptation of the mitral valve leaflets consistent with mitral regurgitation. The ventricular wall remodeling and noncontractility secondary to the infarct results in retraction and tethering of the papillary muscles, which in turn results in incomplete coaptation of the mitral valve leaflets. (Right) Corresponding color Doppler ultrasound confirms severe mitral regurgitation in 755

Diagnostic Imaging Cardiovascular ventricular systole. P.8:105

TERMINOLOGY Definitions Ischemic mitral regurgitation (IMR) is a common complication of myocardial infarction Acute IMR is secondary to papillary muscle infarction and rupture Chronic IMR is due to left ventricular remodeling IMAGING General Features Location Valve consists of anterior and posterior leaflets Free edges are attached by multiple chordae tendineae to both papillary muscles Adequate coaptation of free edges of valve leaflets is necessary to achieve valve competency Infarcts involving posterior descending branch of a dominant right coronary artery may rupture posteromedial papillary muscle Anterolateral muscle is less likely to rupture due to dual blood supply Imaging Recommendations Best imaging tool Echocardiography is clinical gold standard Effective regurgitant orifice area (EROA) can be assessed by several methods 3D echography is superior to 2D transthoracic echocardiography Echogenic papillary muscles, myocardial wall thinning, and ventricular dilation Cardiac CT EROA correlates well with echocardiography grading Advantage over echocardiography in ability to depict obstructive coronary artery disease Regional wall motion abnormalities seen in IMR are not seen in myxomatous mitral degeneration Cardiac MR Steady-state free precession bright blood sequence shows mitral regurgitant jet Mitral regurgitant volume is quantified by subtracting aortic flow volume from left ventricular stroke volume Cardiac MR late enhancement can demonstrate presence, location, and size of infarction DIFFERENTIAL DIAGNOSIS Other Causes of Mitral Regurgitation Rheumatic heart disease Myxomatous degeneration, connective tissue disease Infective endocarditis Mitral valve prolapse, ruptured/elongated chordae tendinea, parachute mitral valve Dilated cardiomyopathy (annulus) PATHOLOGY General Features Etiology Papillary muscle rupture Resulting in malcoaptation of leaflets Left ventricular remodeling Alteration in geometric relationship of annulus, valve leaflets, papillary muscles, and myocardium Regional left ventricular wall dysfunction tethers the papillary muscles and chordae, restricting normal valve closure → regurgitation CLINICAL ISSUES Presentation Most common signs/symptoms Acute IMR is characterized by acute pulmonary edema and cardiogenic shock Chronic IMR is characterized by progressive heart failure Dyspnea, fatigue, raised jugular venous pressure, displaced apex beat Clinical profile Risk factors: Smoking, cholesterol elevation, diabetes, hypertension, family history 756

Diagnostic Imaging Cardiovascular Demographics Epidemiology Angiographic prevalence studies: 1.6-19% Echocardiographic prevalence studies: 8-74% Natural History & Prognosis Post-infarction left ventricle is less compliant Dilation of left atrium and ventricle, pulmonary hypertension, and congestive heart failure If regurgitant volume > 30 mL/beat, then 5-year survival rate is 61% Treatment Medical β-blockers and mineralocorticoid receptor blockers prevent remodeling ACE inhibitors or angiotensin receptor blockers reduce afterload and regurgitant volume Diuretics reduce preload and regurgitant volume Resynchronization therapy Improves left ventricular function, reduces MR Biventricular implantable cardioverter-defibrillators synchronize ventricles in those with QRS > 120 milliseconds Surgery In patients referred for coronary bypass surgery Annuloplasty in those with annular dilation Reimplantation of pap muscle in selected patients SELECTED REFERENCES 1. Arnous S et al: Quantification of mitral regurgitation on cardiac computed tomography: comparison with qualitative and quantitative echocardiographic parameters. J Comput Assist Tomogr. 35(5):625-30, 2011 2. Flachskampf FA et al: Cardiac imaging after myocardial infarction. Eur Heart J. 32(3):272-83, 2011 3. Killeen RP et al: Chronic mitral regurgitation detected on cardiac MDCT: differentiation between functional and valvular aetiologies. Eur Radiol. 20(8):1886-95, 2010 4. Shanks M et al: Quantitative assessment of mitral regurgitation: comparison between three-dimensional transesophageal echocardiography and magnetic resonance imaging. Circ Cardiovasc Imaging. 3(6):694-700, 2010

Left Ventricular Free Wall Rupture Key Facts Terminology Rupture of left ventricular myocardial wall with ensuing communication between left ventricular cavity and pericardial space Usually seen in setting of acute myocardial infarction Often accompanied by acute hemodynamic deterioration or electromechanical dissociation May be contained if inflammatory pericardium seals the rupture Imaging Sudden development of hemopericardium seen on echocardiography, CT, and MR Accompanying wall motion abnormality in respective myocardial segment Size of defect is very variable Top Differential Diagnoses Hemopericardium Pericardial hematoma Pericardial effusion Clinical Issues 2 forms of presentation Acute rupture: Acute tamponade with sudden electromechanical dissociation or severe hypotension Subacute rupture: Moderate to severe pericardial effusion with tamponade and hemodynamic compromise, with modest or progressive hypotension, or without tamponade Symptoms: Chest pain, syncope May be completely asymptomatic if rupture is contained

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(Left) Pathology specimen shows a noncontained rupture of the anterior wall after ST-segment elevation myocardial infarction. Note the slit-like rupture and thrombi due to the resulting hemorrhagic pericardial effusion. In most cases, noncontained rupture of the left ventricular wall leads to instant pericardial tamponade and death. (Right) Contrast-enhanced CT shows contained rupture of the left ventricular apex in an individual with anterior myocardial infarction. Note also a large thrombus .

(Left) Contrast-enhanced CT shows a small, contained rupture of the lateral wall of the left ventricle in a patient with myocardial infarction secondary to occlusion of the left circumflex coronary artery . (Right) Bright blood MR in the same patient also shows the contained rupture . Note the significantly lower spatial resolution of magnetic resonance as compared with computed tomography. P.8:107

TERMINOLOGY Definitions Rupture of left ventricular myocardial wall with ensuing communication between left ventricular cavity and pericardial space Usually seen in setting of acute myocardial infarction Often accompanied by acute hemodynamic deterioration or electromechanic dissociation 2 forms of rupture Acute: Acute tamponade with sudden electromechanical dissociation or severe hypotension Subacute: Moderate to severe pericardial effusion With tamponade and hemodynamic compromise With modest or progressive hypotension Without tamponade 758

Diagnostic Imaging Cardiovascular IMAGING General Features Best diagnostic clue Sudden development of hemopericardium Left ventricular wall motion abnormality Radiographic Findings Radiography Chest radiography findings May be normal Flask-shaped heart, typical of pericardial effusion CT Findings Varying amounts of blood and thrombus in pericardial space Discontinuity of left ventricular myocardium Akinesis or dyskinesis (outward motion) of retrospectively gated cine reconstructions are available MR Findings Various amounts of fluid and thrombus in pericardial space Cine images may demonstrate hypokineses or akinesis of free wall Delayed enhancement may demonstrate transmural hyperenhancement adjacent to hematoma Echocardiographic Findings Echocardiogram 2D echocardiography Varying degrees of pericardial effusion Effusion may contain fibrinous strands or thrombus Typical flap-like dyskinesis of respective myocardial segment Often accompanied by left ventricular thrombus Color Doppler May infrequently be able to demonstrate communication between left ventricle and pericardium, depending on size and extent of defect Angiographic Findings Coronary angiography Occlusion of coronary artery (often small) Left ventricular angiography Regional wall motion abnormality Potentially, communication between left ventricle and pericardial space DIFFERENTIAL DIAGNOSIS Hemopericardium Acute aortic dissection, trauma, neoplasm, consequence of cardiac surgery Pericardial Hematoma Post cardiac surgery Pericardial Effusion Infection, inflammation, uremia PATHOLOGY General Features Associated abnormalities Hemopericardium Acute myocardial infarction Staging, Grading, & Classification 3 typical variants of rupture defect Slit-like: Early infarct Seen within 12 hours of infarction Associated with delayed thrombolysis (> 12 hours after infarction) Erosion at borders of infarct Extension of infarct, intermediate in timing Expansion of infarct Large infarction, late appearing Gross Pathologic & Surgical Features Contained ventricular rupture with blood &/or thrombus in pericardial space CLINICAL ISSUES Presentation 759

Diagnostic Imaging Cardiovascular Most common signs/symptoms Chest pain, syncope May be completely asymptomatic if rupture is contained Clinical profile Occurs early (< 48 hours) or late (2-7 days) post infarction Demographics Age Generally > 60 years (median: 65-70 years) Epidemiology < 1% of all patients with acute myocardial infarction Natural History & Prognosis Very high mortality unless contained rupture Treatment Emergent surgical repair may be attempted High long-term survival rate if surgery is successful Conservative approach may be preferable in patients with contained rupture, lack of severe hemodynamic compromise, and comorbidities SELECTED REFERENCES 1. Haddadin S et al: Surgical treatment of postinfarction left ventricular free wall rupture. J Card Surg. 24(6):624-31, 2009 P.8:108

Image Gallery

(Left) Contrast-enhanced CT reveals a contained rupture of the left ventricular apex that is filled with thrombotic material . The presenting symptom in this patient was a stroke. (Right) Contrast-enhanced CT reformatted in a 4chamber view from the same patient also demonstrates the contained rupture at the apex and reveals a thrombus .

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(Left) Late gadolinium enhancement MR imaging of the same patient shows transmural apical delayed hyperenhancement consistent with infarct and thrombus . Discontinuation of the enhanced myocardium suggests the presence of a contained rupture. (Right) A modified parasternal long-axis view transthoracic echocardiogram of the same patient shows the rupture in the apical region of the left ventricle and blood extending beyond the wall (pseudoaneurysm).

(Left) Intraoperative photograph of the exposed heart of the same patient shows the rupture and thrombotic material contained by inflamed epicardium . The grayish shade of the epicardium (usually clear) indicates post-infarct pericarditis, which is a prerequisite to having enough adhesions to prevent tamponade in case of rupture. (Right) Clinical photograph from the same patient shows the thrombus removed from the pseudoaneurysm after the surgeon opened the latter. P.8:109

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Diagnostic Imaging Cardiovascular

(Left) Coronary angiography shows occlusion of the left circumflex coronary artery . (Right) Contrast-enhanced CT in the same patient shows a very small free wall rupture in the posterolateral region of the left ventricle , which is supplied by the occluded circumflex artery. A small pericardial effusion is present . Within the effusion, several cross sections of a pigtail catheter are visible . The catheter has been placed percutaneously for drainage of the effusion.

(Left) Short-axis reconstruction of the left ventricle in the same patient shows contrast extending radially through the posterolateral left ventricular wall, consistent with a small rupture . (Right) Surgical image from the same patient shows the very small perforation of the left ventricular wall , confirming left ventricular free wall rupture.

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Diagnostic Imaging Cardiovascular

(Left) Echocardiography in a different patient 1 year after transapical aortic valve replacement shows a contained rupture of the left ventricular apex. Note the blood-filled cavity that has ensued. The site of rupture is in the apical myocardium . In the top left, contours have been redrawn for better visualization. (Right) Color Doppler flow signal in the same patient shows the communication between the left ventricular cavity and the contained rupture.

Ventricular Septal Rupture Key Facts Terminology Abnormal communication between right and left ventricles following acute myocardial infarction Typically occurs on day 1 following infarct Results in severe left-to-right shunt Imaging Echocardiogram (best imaging tool) New ventricular septal defect with pattern of right ventricular overload Left-to-right shunt in Doppler echocardiography Chest radiography: Biventricular enlargement, pulmonary edema Cardiac gated CTA: May show focal defect involving ventricular septum with areas of myocardial thinning, hypokinesis, or akinesis adjacent to defect Cardiovascular MR: Provides anatomic detail and shunt quantification Top Differential Diagnoses Congenital ventricular septal defect Not preceded by myocardial infarct Contained rupture of left ventricle Not associated with left-to-right shunt Clinical Issues Sudden chest pain and deterioration of hemodynamics after acute myocardial infarction Immediate placement of intraaortic balloon pump to decrease left ventricular afterload Very high mortality when untreated Treatment options include surgery and interventional closure Mortality remains high even when defect closure is attempted

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(Left) Apical 4-chamber view with color Doppler from a transthoracic echocardiogram shows a post-infarction ventricular septal defect (VSD) with color flow traversing the defect. Echocardiography is typically the 1st imaging modality employed to evaluate suspected VSDs after myocardial infarction. (Right) Axial SSFP from CMR in a patient status post septal myocardial infarction shows a VSD near the apex of the heart. MR allows anatomic evaluation and shunt quantification.

(Left) Short-axis reformat from a cardiac gated CTA shows a contained ventricular septal rupture at the inferior septum with dissection into the right ventricular free wall . Infarction of the posterior septum may cause irregular, serpiginous extension into the myocardium. (Right) Axial NECT of a patient status post percutaneous closure of a post-infarction VSD shows the occlusive components of the Amplatzer occluder on either side of the interventricular septum. P.8:111

TERMINOLOGY Synonyms Post-infarct ventricular septal defect (VSD) Definitions Abnormal communication between right and left ventricles Generally following acute myocardial infarction IMAGING General Features Location Anterior myocardial infarction 764

Diagnostic Imaging Cardiovascular Generally involves apical portion of septum Usually simpler, discrete communication across septum Inferior myocardial infarction Generally involves inferoposterior septum Potentially more complex rupture with irregular, serpiginous tracts through myocardium Size Few mm to several cm Morphology Defect in ventricular septum Size of infarct in part determines prognosis Radiographic Findings Radiography Chest radiography findings Biventricular enlargement Pulmonary congestion CT Findings CTA Gated study demonstrates focal defect involving ventricular septum with areas of myocardial thinning, hypokinesis, or akinesis adjacent to defect MR Findings Multislice 2D gradient-echo Visualizes anatomy of defect Peri-defect hypokinesis or akinesis on cine imaging Delayed post-gadolinium imaging often demonstrates transmural hyperenhancement surrounding septal defect Echocardiographic Findings Echocardiogram New VSD apparent on echocardiogram Pattern of right ventricular overload Wall motion abnormalities corresponding to infarction Color Doppler Left-to-right shunt Angiographic Findings Coronary angiography demonstrates occlusion of infarct vessel Left ventriculography demonstrates left-to-right shunt Imaging Recommendations Best imaging tool Doppler echocardiography DIFFERENTIAL DIAGNOSIS Congenital Ventricular Septal Defect Not preceded by myocardial infarct Contained Rupture of Left Ventricle Not associated with left-to-right shunt PATHOLOGY General Features Etiology Complication of anterior or inferior myocardial infarction Typically occurs 1-5 days after acute infarct Necrosis of ventricular septum Direct communication across septum, usually at ventricular apex for anterior infarction Often dissection of right ventricular free wall with complex communication to right ventricular cavity for inferior infarction CLINICAL ISSUES Presentation Most common signs/symptoms Recurrent chest pain after infarction Shortness of breath Heart failure and hypotension Demographics 765

Diagnostic Imaging Cardiovascular Epidemiology 1-2% incidence following acute myocardial infarction prior to revascularization era Natural History & Prognosis Untreated symptomatic patients have extremely high mortality Surgical treatment is also associated with high mortality Treatment Medical therapy to reduce afterload using intraaortic balloon pump Interventional occlusion of ventricular septal defect can be attempted Surgical treatment has high perioperative risk Pericardial patch ± infarct resection SELECTED REFERENCES 1. Tada N et al: Percutaneous closure of post-infarction ventricular septal defect using an Amplatzer septal occluder. Cardiovasc Interv Ther. 28(2):216-21, 2013 2. Vargas-Barrón J et al: Risk factors, echocardiographic patterns, and outcomes in patients with acute ventricular septal rupture during myocardial infarction. Am J Cardiol. 95(10):1153-8, 2005 3. Birnbaum Y et al: Ventricular septal rupture after acute myocardial infarction. N Engl J Med. 347(18):1426-32, 2002 4. Crenshaw BS et al: Risk factors, angiographic patterns, and outcomes in patients with ventricular septal defect complicating acute myocardial infarction. GUSTO-I (Global Utilization of Streptokinase and TPA for Occluded Coronary Arteries) Trial Investigators. Circulation. 101(1):27-32, 2000

Post-Angioplasty Restenosis Key Facts Terminology In-stent restenosis (ISR) angiographic definition: Recurrent diameter stenosis > 50% at stent site or at its edges (adjacent 5 mm segments) Imaging CTA Reduction in stent lumen on various coronary imaging modalities Evaluation of coronary stents > 2.5 mm in diameter appears feasible Multidetector CT has sensitivity of 91.8% and specificity of 93.8% for evaluable stents, using in-stent attenuation to aortic attenuation ratio of 0.81 Invasive coronary angiography is superior to cardiac CTA for evaluation of smaller stents Top Differential Diagnoses Coronary artery stenosis Stent thrombosis Post angioplasty dissection Pathology ISR is attributable to neointimal hyperplasia Clinical Issues Most often asymptomatic restenosis Can re-present with typical ischemic symptoms Medical Prevention is achieved by dual antiplatelet after drug-eluting stents implantation therapy and lipid control Interventional Stent placement is preferred over balloon angioplasty in patients with ISR Surgical Coronary bypass if not amenable to percutaneous treatment, or in patients with multivessel disease

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(Left) Invasive coronary angiogram shows a stent placed in the proximal segment of the left anterior descending coronary artery for an obstructive stenosis. The stent lumen was widely patent post procedure at that time. (Right) Coronary CTA performed 3 years later for recurrent chest pain (same patient) shows low attenuation within the stent lumen , consistent with in-stent restenosis. Note the calcified plaque in the wall of the native left anterior descending coronary artery.

(Left) Corresponding coronary CTA using an edge-enhanced kernel shows sharper stent walls with less blooming artifact. This allows better delineation of the low-attenuation material within the stent lumen, consistent with instent restenosis. (Right) Corresponding invasive angiogram confirms in-stent restenosis within the left anterior descending coronary artery stent . Subsequent stent-within-a-stent procedure was performed with symptom resolution. Also note stenosis at the diagonal branch takeoff. P.8:113

TERMINOLOGY Definitions In-stent restenosis (ISR) has angiographic definition: Recurrent diameter stenosis > 50% at stent site or its edges (adjacent 5 mm) IMAGING General Features Best diagnostic clue Reduction in stent lumen on various modalities Size Lumen diameter/area after treatment is major predictor of restenosis 767

Diagnostic Imaging Cardiovascular Morphology Varied characteristics of stenotic lesion Concentric or eccentric; smooth or rough May have “candy wrapper” stenosis due to plaque progression proximal and distal to stent CT Findings CTA Evaluation of coronary stents > 2.5 mm in diameter appears feasible Multidetector CT shows sensitivity of 91.8% and specificity of 93.8% for evaluable stents, using in-stent attenuation to aortic attenuation ratio of 0.81 Higher for left main stents: Sensitivity 100%; specificity 91% Blooming artifact from metal struts is a problem, particularly for smaller stents On average, nearly 1/2 of in-stent lumen is affected by blooming artifacts Angiographic Findings Invasive coronary angiography Diffuse or focal lesion development May show evidence of dissection Superior to cardiac CTA for evaluation of smaller stent IVUS to evaluate ISR anatomical severity and location Optical coherence tomography has higher resolution, adding insight to neointimal composition Fractional flow reserve constitutes physiological assessment of ISR severity DIFFERENTIAL DIAGNOSIS Coronary Artery Stenosis New coronary stenosis on nontreated segment Incompletely stented lesion Stent Thrombosis Stent occlusion Post-Angioplasty Dissection Intimal tear → contrast on both sides of intimal flap PATHOLOGY General Features Etiology Balloon angioplasty is associated with vascular injury Healing results in tissue ingrowth and restenosis Reduction in area delimited by external and internal elastic lamina ISR is attributable to neointimal hyperplasia Staging, Grading, & Classification ACC/AHA lesion classification system reflects low, moderate, and high risk of failure based on morphological patterns Mehran classification for ISR is also used and shows recurrent ISR more frequently with increasing grades of classification (I-IV) CLINICAL ISSUES Presentation Most common signs/symptoms Most often asymptomatic restenosis Can re-present with typical ischemic symptoms Recurrent angina, acute myocardial infarction, heart failure Demographics Epidemiology ISR occurs in 16-35% of bare metal stents (BMS) and in 4-11% of drug-eluting stents (DES) Greater incidence after treatment of total occlusion, small vessels, long lesions, thrombus, complicated dissections Treatment Medical Prevention: Dual antiplatelet after DES implantation therapy and lipid control Interventional Stent placement is preferred over balloon angioplasty in patients with ISR DES using lipophilic antiproliferative drugs reduces neointimal hyperplasia, compared with BMS Prevention is achieved by careful balloon sizing, using IVUS to guide expansion

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Diagnostic Imaging Cardiovascular Rotational atherectomy is reasonable for fibrotic or heavily calcified lesions not crossed by balloon catheter or adequately dilated pre-stent implantation Surgical Coronary bypass for severe stenoses not amenable to percutaneous treatment, or for multivessel disease DIAGNOSTIC CHECKLIST Image Interpretation Pearls On coronary CTA, filling defects in evaluable stents are suspicious for ISR SELECTED REFERENCES 1. Park SJ et al: In-stent neoatherosclerosis: a final common pathway of late stent failure. J Am Coll Cardiol. 59(23):2051-7, 2012 2. Tsigkas GG et al: Stent restenosis, pathophysiology and treatment options: a 2010 update. Hellenic J Cardiol. 52(2):149-57, 2011 3. Abdelkarim MJ et al: Noninvasive quantitative evaluation of coronary artery stent patency using 64-row multidetector computed tomography. J Cardiovasc Comput Tomogr. 4(1):29-37, 2010

In-Stent Restenosis Key Facts Terminology Stenosis > 50% diameter reduction of coronary artery lumen inside or at edges of implanted stent Focal in-stent restenosis (ISR): Short stenosis anywhere within stent Diffuse ISR: Stenosis along entire length of implanted stent Imaging Identification of in-stent stenosis by coronary CTA is problematic and prone to false-positive results Stents ≥ 3.0 mm in diameter are easier to assess on CT angiography for ISR than smaller ones Since left main (LM) coronary artery is larger caliber vessel and displays relatively little motion artifact, CT angiography is relatively reliable to exclude in-stent stenosis in LM stents Top Differential Diagnoses De novo coronary artery stenosis Acute stent thrombosis Clinical Issues Factors that influence restenosis include stent type, length, and diameter Small-diameter stents, long lesions, ostial lesions, and bifurcation lesions have higher rates of restenosis More frequent in patients with diabetes Drug-eluting stents markedly reduce incidence Trade-off with drug-eluting stents: Increased rates of acute stent thrombosis, which mandate longer duration of post-PCI dual antiplatelet therapy Risk for acute stent thrombosis is likely mediated by polymer that carries antiproliferative drug, not by the drug itself

(Left) Graphic shows (1) normal appearance of a coronary artery stent); (2) diffuse in-stent restenosis, which is typically rather concentric (most frequent type); (3) focal in-stent restenosis (ISR) with a short lesion within the stent 769

Diagnostic Imaging Cardiovascular (less frequent type); and (4) new lesions (called “de novo stenoses”) that may develop outside the stent. (Right) Invasive coronary angiography shows diffuse ISR of a stent placed in the ostial segment of an aortocoronary bypass graft. Note beginning and end of the stent .

(Left) Contrast-enhanced coronary angiography in the same patient demonstrates a cross section of the stent . Concentric in-stent stenosis and a narrowed lumen are visible. (Right) Multiplanar reconstruction of a contrastenhanced coronary angiography in the same patient shows a longitudinal view of the stent with diffuse ISR over the entire length of the implanted stent . P.8:115

TERMINOLOGY Abbreviations In-stent restenosis (ISR) Definitions Stenosis > 50% diameter reduction of coronary artery lumen inside or at edges of implanted stent 2 different morphologies Focal ISR: Short stenosis anywhere within stent Diffuse ISR: Stenosis along entire length of implanted stent IMAGING CT Findings CTA Coronary CTA Gated cardiac CTA is emerging tool for assessing stent patency Overall, identification of ISR by CT is problematic and prone to false-positive results Metal stent structure is prone to cause artifacts Blooming artifact due to partial volume effects makes stent struts appear thicker and lumen look smaller Beam hardening and motion artifacts cause areas of hypoattenuation inside stent lumen and mimic stenoses Image reconstruction should be performed with sharp (high-resolution) kernels and thinnest possible slice thickness to improve interpretability Stent size is major determinant of interpretability by CT Stents ≥ 3.0 mm in diameter are more likely assessable for ISR than are smaller ones Since left main coronary artery is larger-caliber vessel and displays relatively little motion artifact, MDCT is relatively reliable in excluding in-stent stenosis in left main coronary artery stents Bioabsorbable scaffolds are currently being introduced as an alternative to conventional stents made of metal Bioabsorbable material (e.g., polylactic acid) may be nonradiopaque and not visible on CT Such scaffolds typically have metal markers at either end 770

Diagnostic Imaging Cardiovascular MR Findings MRA Direct visualization of in-stent lumen is not possible because metallic stents cause susceptibility and radiofrequency artifacts on MRA, which lead to local signal void Stress MR and MR myocardial perfusion imaging can be used to detect hemodynamically relevant ISR Echocardiographic Findings Echocardiogram Cannot directly visualize coronary stents or in-stent stenosis Stress echocardiography can identify wall motion abnormalities due to hemodynamically relevant instent stenosis Angiographic Findings Conventional Quantitative coronary angiography is clinical gold standard for detecting ISR and determining degree of stenosis Intravascular ultrasound may be useful adjunct May be helpful in further characterizing lesion and quantifying the degree of stenosis Can identify incomplete stent expansion, malapposition of stent struts, and stent fracture Optical coherence tomography is optimal method to assess stent expansion, malapposition, and stent fracture, but it is infrequently applied Nuclear Medicine Findings Stress myocardial perfusion (by single-photon emission computed tomography [SPECT] or positron emission tomography [PET]) can identify stress-induced hypoperfusion due to hemodynamically relevant in-stent stenosis DIFFERENTIAL DIAGNOSIS De Novo Coronary Artery Stenosis New coronary stenosis in segment not previously treated by stent implantation Exact position of previously implanted stents can (infrequently) be difficult to identify in invasive coronary angiography Therefore, it is occasionally impossible to differentiate in-stent stenosis from de novo stenosis Acute Stent Thrombosis Sudden narrowing of stent lumen due to thrombus formation Acute: < 24 hours of stent placement Subacute: 1-30 day(s) after stent placement Late: > 1 month to 1 year after stent placement Very late: ≥ 1 year after stent placement Usually complete occlusion with consequence of ST-segment elevation myocardial infarction High mortality Subacute: 1-30 days after intervention Late: After 30 days of intervention Post-Stent Aneurysm Coronary aneurysm after stent implantation is very rare complication Aneurysm could result from inflammation due to hypersensitivity reaction to metal or, in drug-eluting stents, to drug or polymer that carries drug PATHOLOGY General Features Etiology Multiple risk factors for ISR Long total stent length Small stent diameter Diabetes Ostial location Stent location in left main coronary artery Bifurcation Neointimal proliferation from arterial damage P.8:116

Generally diffuse process but may be focal Macrophage accumulation with cellular proliferation 771

Diagnostic Imaging Cardiovascular In-stent stenosis usually occurs within 1st 6 months of coronary stent placement Staging, Grading, & Classification 4 described patterns of ISR Pattern I Focal lesion (< 10 mm length) within stent Pattern II Diffuse lesion (> 10 mm length) within stent Pattern III Stenosis (> 10 mm length) extending outside stent Pattern IV Totally occluded stent Microscopic Features Pathophysiology of ISR is multifactorial and comprises Inflammation Smooth muscle cell migration and proliferation Extracellular matrix formation All mediated by distinct molecular pathways CLINICAL ISSUES Presentation Most common signs/symptoms Recurrent angina is most likely symptom and develops within 1st 6 months of stent placement After 1 year, recurrent angina is more likely due to progression of nonculprit lesions ISR may be completely asymptomatic Other signs/symptoms Acute myocardial infarction is unlikely to result from restenosis This presentation is more likely to result from acute stent thrombosis Mechanism (thrombus formation rather than neointimal proliferation) is different from ISR Demographics Epidemiology Bare metal stents At 1 year, target lesion or target vessel revascularization is performed in 12-14% of cases Factors that influence restenosis include stent type, stent length, and stent diameter Small vessels, long lesions, ostial lesions, and bifurcation lesions have higher rates of restenosis Diabetes predisposes patients to ISR Drug-eluting stents Markedly reduces incidence of ISR and rate of target vessel revascularization Trade-off: Increased rate of acute stent thrombosis that mandates longer duration of dual antiplatelet therapy post percutaneous coronary intervention (PCI) Risk for acute stent thrombosis is likely mediated by polymer that carries antiproliferative drug, not by the drug itself Treatment Prevention Adequate stent deployment and expansion Use of drug-eluting stents in lesions and patients with high risk of restenosis Repeat percutaneous coronary intervention Repeat stenting or treatment with drug-eluting balloon is currently the preferred approach for treating restenosis Bypass surgery may be necessary Intravascular ultrasound guidance is helpful in evaluating restenotic stent as well as peri-stent areas Due to high rates of subsequent stent thrombosis, radiotherapy is no longer used to prevent or treat ISR DIAGNOSTIC CHECKLIST Consider Testing for in-stent stenosis can be through angiography (direct stent visualization) or testing for ischemia (clinically recommended approach) Invasive angiography and intravascular ultrasound are the reference standards for determining the severity of instent stenosis and planning intervention Coronary CTA may be useful for stents > 3 mm in diameter, such as stents in left main coronary artery, but always requires optimal image quality 772

Diagnostic Imaging Cardiovascular Coronary CTA is frequently false-positive for stenosis in setting of implanted coronary stents Image Interpretation Pearls Main artifacts caused by stent on CTA, all of which lead to false-positive interpretation Blooming artifact (partial volume artifact) Beam hardening artifact Motion artifact SELECTED REFERENCES 1. Andreini D et al: Coronary in-stent restenosis: assessment with CT coronary angiography. Radiology. 265(2):410-7, 2012 2. Chung SH et al: Evaluation of coronary artery in-stent restenosis by 64-section computed tomography: factors affecting assessment and accurate diagnosis. J Thorac Imaging. 25(1):57-63, 2010 3. de Graaf FR et al: Diagnostic accuracy of 320-row multidetector computed tomography coronary angiography to noninvasively assess in-stent restenosis. Invest Radiol. 45(6):331-40, 2010 4. Sun Z et al: Diagnostic accuracy of 64 multislice CT angiography in the assessment of coronary in-stent restenosis: a meta-analysis. Eur J Radiol. 73(2):266-73, 2010 5. Serruys PW et al: A bioabsorbable everolimus-eluting coronary stent system (ABSORB): 2-year outcomes and results from multiple imaging methods. Lancet. 373(9667):897-910, 2009 6. Hoffmann R et al: Coronary in-stent restenosis - predictors, treatment and prevention. Eur Heart J. 21(21):1739-49, 2000 7. Mehran R et al: Angiographic patterns of in-stent restenosis: classification and implications for long-term outcome. Circulation. 100(18):1872-8, 1999 8. Hoffmann R et al: Patterns and mechanisms of in-stent restenosis. A serial intravascular ultrasound study. Circulation. 94(6):1247-54, 1996 P.8:117

Image Gallery

(Left) Contrast-enhanced CT demonstrates the normal appearance of an implanted stent in the ostium of the left main coronary artery. No in-stent stenosis is present . (Right) Invasive coronary angiography in the same patient shows absence of in-stent stenosis in the implanted stent in the ostium of the left main coronary artery . The stent material itself is typically not visible in invasive angiography, especially in the absence of in-stent stenosis.

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(Left) Contrast-enhanced coronary CT angiography demonstrates focal in-stent stenosis of a coronary artery stent in the proximal left anterior descending (LAD) coronary artery. (Right) Invasive catheter-based coronary angiography of the same patient shows the short, focal in-stent stenosis although it is not always possible to see the stent itself in invasive coronary angiography.

(Left) Contrast-enhanced coronary CT angiography shows that 2 focal in-stent stenoses are present in a long-stented segment of the right coronary artery . This finding is rather unusual. (Right) Invasive catheter-based coronary angiography of the same patient also demonstrates that 2 focal restenoses are present in the stent of the proximal and mid portions of the right coronary artery. P.8:118

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(Left) Multiplanar reconstruction of a contrast-enhanced coronary CT angiography displays a longitudinal view of a short coronary artery stent placed in the ostium of an intermediate branch (ramus). A diffuse, high-grade in-stent stenosis is present. (Right) Invasive catheter-based coronary angiography of the same patient demonstrates diffuse concentric narrowing of the most proximal intermediate branch (ramus). The stent itself cannot be seen.

(Left) Curved multiplanar reconstruction of a venous bypass graft and the distal obtuse marginal branch shows that a coronary artery stent (2.5 mm diameter) is implanted in the obtuse marginal branch just distal to the bypass anastomosis. Diffuse signal intensity drop within the stent suggests possible in-stent stenosis, but the confidence level is low. (Right) Invasive catheter-based coronary angiography of the same patient shows that a diffuse high-grade ISR is present.

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(Left) Contrast-enhanced coronary CTA shows a false-positive finding within a coronary artery stent implanted in the right coronary artery. A loss of signal intensity within the stent suggests focal high-grade ISR . (Right) Invasive catheter-based coronary angiography of the same patient shows no significant in-stent stenosis in the mid right coronary artery . The CT result was false-positive. False-positive findings are relatively frequent when assessing stents by coronary CTA. P.8:119

(Left) False-positive findings are frequent when assessing coronary stents on CT angiography. They are caused by the high-density material of the stent. In this case, there is the impression of a high-grade focal ISR of the LAD coronary artery. (Right) Invasive catheter-based coronary angiography of the same patient shows the proximal LAD. Only a very mild in-stent stenosis is present .

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(Left) The lumen of a large stent (4.0 mm) in the proximal left circumflex artery can be assessed and is obviously without restenosis . A smaller stent (2.5 mm) placed on the obtuse marginal branch cannot be assessed on CT. (Right) Motion artifacts often cause false-positive findings on coronary CTA. Here, the same stent is shown in a systolic (left) and diastolic (right) reconstruction. Slight motion in the systolic reconstruction causes the impression of ISR.

(Left) Not all stents have high density on CT. Contrast-enhanced CTA shows LAD segment treated by implantation of a biodegradable scaffold (Absorb) with 2 small platinum markers at either end. The scaffold material (polylactic acid) is not radiopaque. (Right) Invasive catheter-based coronary angiography shows the treated LAD segment. No instent stenosis is present. Start and end of stent are also shown. Note coronary anomaly with a right-sided left main origin.

Post-CABG Thrombosis Key Facts Terminology Acute saphenous vein graft failure due to subtotal or total occlusive thrombosis In early (< 1 month) postoperative period, acute thrombosis is dominant etiology Thrombosis, intimal hyperplasia, and accelerated atherosclerosis contribute to graft failure in the acute, subacute, and late postoperative periods, respectively Imaging Invasive coronary angiography Can demonstrate graft occlusion but grafts can be difficult to locate CTA 777

Diagnostic Imaging Cardiovascular High accuracy for bypass graft occlusions May show only smooth small focus of contrast outpouching at aortic root in chronic setting May demonstrate complete absence of luminal contrast in total occlusion with low-density luminal material (thrombus) Top Differential Diagnoses Coronary artery stenosis CABG atherosclerosis Perioperative infarction Clinical Issues Recurrent angina is the most common presentation Perioperative antiplatelet therapy can reduce early thrombosis and graft failure Metaanalysis supports use of drug-eluting stents over bare metal stents for saphenous vein graft interventions Use “no touch” technique for harvesting grafts, preventing disruption to endothelium

(Left) Invasive angiogram in a 70-year-old man with recurrent chest pain 8 years post CABG shows a catheter within the ostium of a vein graft to the right coronary artery (RCA). The graft is completely thrombosed with only a stump filling with contrast. (Right) Corresponding angiogram in the same patient shows a catheter in the ostium of a vein graft to the 1st obtuse marginal branch. The graft is completely thrombosed . Note surgical clips on a left internal mammary artery (LIMA) graft.

(Left) Corresponding oblique 3D volume-rendered cardiac CT image shows that both vein grafts are completely thrombosed . Note that the LIMA graft to the distal left anterior descending (LAD) coronary artery appears patent throughout. (Right) Corresponding axial coronary CTA reformat confirms occluded saphenous vein grafts to the RCA territory and the left circumflex territory (1st obtuse marginal branch) and a patent LIMA graft to the LAD. Normally, LIMA grafts are smaller in diameter than saphenous vein grafts. 778

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TERMINOLOGY Abbreviations Coronary artery bypass graft (CABG) Definitions Saphenous vein graft failure due to subtotal or total occlusive thrombosis Thrombosis, intimal hyperplasia, and accelerated atherosclerosis contribute to graft failure in acute, subacute, and late postoperative periods, respectively In early (< 1 month) postoperative period, acute thrombosis is dominant etiology IMAGING General Features Best diagnostic clue Acute subtotal/total occlusion of saphenous vein graft by thrombus Invasive coronary angiography is traditional gold standard but is invasive CTA is excellent for graft depiction Location Aortocoronary reversed saphenous vein grafts Morphology Low-density material within graft lumen May also demonstrate graft expansion Absence of contrast in lumen Radiographic Findings Radiography Usually nonspecific postoperative finding Rarely, chest radiograph may reveal severe acute pulmonary edema if acute occlusion leads to cardiogenic shock CT Findings NECT May demonstrate material of slightly increased density within occluded graft lumen CTA Provides high-quality images of venous bypass graft occlusions May demonstrate complete absence of luminal contrast in total occlusion with low-density luminal material (thrombus) May demonstrate crescentic rim of contrast in subtotal occlusion May demonstrate expansion of vein graft Smooth broad-based area of contrast outpouching at aortic anastomosis may be best clue Beware: Aortic cannulation sites can mimic outpouching at occluded graft anastomosis Problems with CTA graft evaluation Difficulty evaluating native coronary arteries (usually heavily calcified) Clips adjacent to left internal mammary artery can cause beam hardening artifact Longer range required to include left internal mammary artery origin results in higher radiation dose Anastomosis can be difficult to evaluate MR Findings MRA 3D gadolinium-enhanced MR techniques are more sensitive than 2D gradient-echo or spin-echo techniques for detecting graft occlusion Sensitivity = 85%; specificity = 94% Respiratory navigating markedly improves image quality but is time consuming Occluded grafts are absent; correlation with operative notes is crucial May demonstrate small smooth outpouching of contrast at aortic anastomosis Angiographic Findings Invasive coronary angiography Can demonstrate graft occlusion, but grafts may be difficult to locate Can be time consuming Ventriculography Regional wall motion abnormalities 779

Diagnostic Imaging Cardiovascular Nuclear Medicine Findings Nuclear cardiology findings Thallium or technetium imaging Reduced tracer uptake in ischemic segments Imaging Recommendations Best imaging tool Coronary CTA (noninvasive, fast, highly sensitive/specific) Coronary angiography Traditional gold stand but time consuming May not locate all grafts Protocol advice Include takeoff of left internal mammary artery from subclavian artery to avoid missing left internal mammary artery ostial stenosis or subclavian artery stenosis proximal to left internal mammary artery origin DIFFERENTIAL DIAGNOSIS Coronary Artery Stenosis New stenosis on native coronary arteries Coronary Artery Bypass Graft Atherosclerosis Within 1st postoperative year, often due to perianastomotic narrowing (especially in 1st 3 months) After 1st postoperative year, typically due to atherosclerosis within native coronary vessels or grafts Perioperative Infarction Seen especially in left main stenosis and triple vessel disease PATHOLOGY General Features Etiology Endothelial injury Direct physical trauma during surgery Leukocyte response Ischemia of wall after loss of vasa vasorum Risk factors such as smoking, elevated low density lipoprotein cholesterol P.8:122

Low saphenous vein graft flow Small luminal size of recipient artery Diseased native artery distal to anastomosis Bypass of nonhemodynamically significant lesion (< 70% stenosis) due to competitive flow from native vessel Local atheroma development within vein graft Technical factors Narrow distal anastomosis Insufficient/excessive graft length Mismatched size of graft to recipient artery Angle of graft to aorta < 90° can lead to kinking Resistance to antiplatelet agents Loss of endothelium with accumulation of fibrin Adherence of platelets and white blood cells Thrombus occluding vessel lumen, especially at sites of anastomosis Gross Pathologic & Surgical Features Atherosclerosis is diffuse and concentric Lesions are friable and fragile Prone to atherosclerotic embolism, particularly during reoperation Microscopic Features Fibrous cap is absent or weak and thin Foam cells and lipid debris are exposed to bloodstream Infiltrate of inflammatory cells and lipid-laden multinucleate giant cells CLINICAL ISSUES Presentation Most common signs/symptoms 780

Diagnostic Imaging Cardiovascular Recurrent angina (most common presentation) Myocardial infarction New/worsening heart failure Arrhythmias Sudden death Natural History & Prognosis Early vein graft failure due to thrombosis occurs in as many as 18% of cases Vein graft failure is associated with worse clinical outcomes Treatment Medical Perioperative antiplatelet therapy can reduce early thrombosis and graft failure Lipid lowering can attenuate process of atherosclerosis in vein grafts Interventional Balloon angioplasty: Unsatisfactory restenosis rate of at least 45% Metaanalysis supports use of drug-eluting stents over bare metal stents for saphenous vein graft interventions Therapeutic ultrasound thrombolysis in setting of acute coronary syndrome has been evaluated but leads to increased incidence of ischemic complications Surgical Avoid endothelial injury during harvesting Use “no touch” technique for harvesting grafts, preventing disruption to endothelium Avoid excessive manual distension Some use α-adrenergic antagonist solutions to minimize vasospasm DIAGNOSTIC CHECKLIST Consider In patients re-presenting with angina post CABG Obstruction/occlusion in grafts or native vessels SELECTED REFERENCES 1. Hillis LD et al: 2011 ACCF/AHA Guideline for Coronary Artery Bypass Graft Surgery: executive summary: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 124(23):2610-42, 2011. Erratum in: Circulation. 124(25):e956, 2011. Circulation. 126(7):e105, 2012 2. Jeremy JY et al: Pharmacological strategies aimed at reducing complications associated with coronary artery bypass graft surgery. Curr Opin Pharmacol. 12(2):111-3, 2012 3. Wan S et al: Vein graft failure: current clinical practice and potential for gene therapeutics. Gene Ther. 19(6):630-6, 2012 4. Gluckman TJ et al: Effects of aspirin responsiveness and platelet reactivity on early vein graft thrombosis after coronary artery bypass graft surgery. J Am Coll Cardiol. 57(9):1069-77, 2011 5. Lee MS et al: Comparison by meta-analysis of drug-eluting stents and bare metal stents for saphenous vein graft intervention. Am J Cardiol. 105(8):1076-82, 2010 6. Parang P et al: Coronary vein graft disease: pathogenesis and prevention. Can J Cardiol. 25(2):e57-62, 2009 7. Ropers D et al: Diagnostic accuracy of noninvasive coronary angiography in patients after bypass surgery using 64slice spiral computed tomography with 330-ms gantry rotation. Circulation. 114(22):2334-41; quiz 2334, 2006 8. Frazier AA et al: Coronary artery bypass grafts: assessment with multidetector CT in the early and late postoperative settings. Radiographics. 25(4):881-96, 2005 9. Serna DL et al: Antifibrinolytic agents in cardiac surgery: current controversies. Semin Thorac Cardiovasc Surg. 17(1):52-8, 2005 10. Yilmaz MB et al: Late saphenous vein graft occlusion in patients with coronary bypass: possible role of aspirin resistance. Thromb Res. 115(1-2):25-9, 2005 11. Enzweiler CN et al: Diameter changes of occluded venous coronary artery bypass grafts in electron beam tomography: preliminary findings. Eur J Cardiothorac Surg. 23(3):347-53, 2003 12. Singh M et al: Treatment of saphenous vein bypass grafts with ultrasound thrombolysis: a randomized study (ATLAS). Circulation. 107(18):2331-6, 2003 13. Stone GW et al: Prospective, randomized evaluation of thrombectomy prior to percutaneous intervention in diseased saphenous vein grafts and thrombus-containing coronary arteries. J Am Coll Cardiol. 42(11):2007-13, 2003 14. Shuhaiber JH et al: Mechanisms and future directions for prevention of vein graft failure in coronary bypass surgery. Eur J Cardiothorac Surg. 22(3):387-96, 2002 15. Motwani JG et al: Aortocoronary saphenous vein graft disease: pathogenesis, predisposition, and prevention. Circulation. 97(9):916-31, 1998

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Diagnostic Imaging Cardiovascular 16. Fitzgibbon GM et al: Coronary bypass graft fate and patient outcome: angiographic follow-up of 5,065 grafts related to survival and reoperation in 1,388 patients during 25 years. J Am Coll Cardiol. 28(3):616-26, 1996 P.8:123

Image Gallery

(Left) Coronary CTA shows an occluded graft to an obtuse marginal branch. Occluded vein grafts have a characteristic “button” appearance off the aortic wall when they occlude. Note the occluded stent in a vein graft to a diagonal branch. (Right) Corresponding coronal oblique coronary CTA shows both grafts with a “button” appearance typical of occluded vein grafts. Note left aortic cusp focal dissection from an attempted left main stent procedure.

(Left) Invasive coronary angiogram in a 76-year-old man with history of CABG 12 years prior shows tip of catheter in the subclavian artery at the LIMA ostium and no contrast in the expected path of LIMA outlined by surgical clips . (Right) Axial coronary CT (same patient) shows a LIMA graft that is occluded throughout its length. Note that LIMA is absent from its normal anterior chest wall position . The normal position of the right internal mammary artery (RIMA) excludes a RIMA graft.

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(Left) 3D volume-rendered image shows a very thin graft to LAD. This radial graft appears diffusely diseased and thready with an obstruction in its distal portion. 3D VRT images are useful for giving an overview of graft configuration. (Right) Corresponding invasive coronary angiogram confirms a diffusely diseased radial artery graft to LAD with an obstruction in its distal portion.

Post-CABG Atherosclerosis Key Facts Terminology Postoperative atherosclerotic disease of bypass grafts or native coronary arteries Imaging Stenosis or occlusion of graft or native coronary artery on coronary angiography or cardiac CT Sensitivity, specificity, and positive and negative predictive values for > 50% stenosis are 100%, 96%, 97.5%, and 100%, respectively, using 64-slice multidetector CT Accuracy for native coronary arteries is decreased due to advanced disease and high prevalence of coronary calcium Invasive coronary angiography: Clinical gold standard Demonstrates degree of luminal stenosis or occlusion Clinical Issues Angina recurs in 15-20% of patients during 1st year postop 10% of all grafts fail early (within 1 month) due to thrombotic occlusion Cumulative graft failure rate of 50% at 10 years postop Graft failure rate of 10% at 10 years postop Antiplatelet therapy can reduce graft failure Stenting is preferred over balloon angioplasty Drug-eluting stents are preferred over bare metal stents for saphenous veins graft interventions State of distal vasculature influences bypass graft patency Diagnostic Checklist Post-CABG atherosclerosis in patients with recurrence of angina postoperatively

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(Left) Invasive angiogram is from a 67-year-old woman with recurrent chest pain 8 years post CABG. Difficulty cannulating the left subclavian artery precluded evaluation of the left internal mammary artery (LIMA) graft. (Right) Corresponding angiogram shows significant ostial stenosis of the left subclavian artery . Note less severe subclavian artery stenosis and poorly opacified LIMA graft . Significant ostial or proximal stenosis of the subclavian artery affects the LIMA graft function and may cause steal.

(Left) Subsequent stress adenosine perfusion cardiac MR demonstrates a subendocardial perfusion defect in the left ventricular mid-anterior and anteroseptal segments in the left anterior descending artery vascular territory. (Right) Corresponding coronary CTA demonstrates the underlying etiology for the recurrent chest pain and inducible ischemia. High-grade stenosis is identified on the left subclavian artery origin from the aortic arch , resulting in poor LIMA perfusion. P.8:125

TERMINOLOGY Abbreviations Coronary artery bypass graft (CABG) Definitions Postoperative atherosclerotic disease of bypass grafts or native coronary arteries IMAGING General Features Best diagnostic clue Stenosis or occlusion of graft or native coronary artery on coronary angiography or cardiac CT Location Bypass conduits may include 784

Diagnostic Imaging Cardiovascular Left or right internal mammary artery Radial artery segments Autologous reversed saphenous veins grafts CT Findings CTA Multidetector CT Sensitivity: 100% Specificity: 96% Positive predictive value: 97.5% Negative predictive value: 100% Accuracy for native coronary arteries is lower than in general population due to advanced disease and high prevalence of coronary calcium Retrospectively ECG-gated, tube-modulated imaging allows high-quality images of arterial and venous bypass grafts Dual acquisition protocols during single contrast injection are promising new tool High-pitch prospective or nongated high-pitch acquisition covering the entire thorax followed immediately by prospectively triggered or retrospectively gated acquisition of the heart only Allows assessment of left internal mammary artery origin and coronary arteries while maintaining low overall radiation dose Superior to invasive angiography for true diameter measurements of grafts as mural thrombus is visible Aneurysm size is often underestimated on angiography Cardiac CTA with sagittal reconstructions and 3D reconstructions best demonstrate relationship and proximity of grafts to the sternum and sternal wires prior to redo sternotomy May demonstrate subendocardial fatty metaplasia or hypoattenuation in areas of prior infarct MR Findings MRA 3D gadolinium-enhanced techniques are more sensitive than 2D gradient-echo or spin-echo techniques Sensitivity: 85% Specificity: 94% Respiratory navigating markedly improves image quality but takes substantially more time Phase-contrast velocity encoding of graft blood flow enables estimation of coronary flow reserve Coronary flow reserve is useful for identifying hemodynamically significant stenosis and influencing need for intervention However, it is still experimental MR cine Global and regional ventricular function can be assessed with steady-state free precession sequences Good left ventricular function (postoperatively) associated with better long-term clinical outcome Delayed enhancement Depicts volume of infarcted tissue Correlates well with Elevated biomarkers Long term clinical outcome Echocardiographic Findings Echocardiogram Transthoracic Doppler echo has high accuracy for detecting left internal mammary artery graft stenosis Up to 10% of left internal mammary arteries are not visualized Other techniques may provide more complete evaluation Angiographic Findings Invasive coronary angiography Clinical gold standard Demonstrates degree of luminal stenosis or occlusion Finding and cannulating the coronary graft ostium can be challenging and may preclude assessment Ventriculography Abnormal wall motion Nuclear Medicine Findings PET High sensitivity and moderate specificity for predicting improvement in function postoperatively 785

Diagnostic Imaging Cardiovascular Improvement is most strongly predicted when ≥ 3 dysfunctional myocardial segments have a relative FDG uptake > 45% of normal myocardium Stress technetium or sestamibi imaging Reduced tracer uptake in ischemic areas corresponding to areas of decreased perfusion/infarction Imaging Recommendations Best imaging tool Invasive coronary angiography Cardiac CT DIFFERENTIAL DIAGNOSIS Graft Thrombosis Occurs in early postoperative period May occur in absence of graft atherosclerotic disease Subclavian Artery Stenosis Proximal to Left Internal Mammary Artery Origin May have same effect as left internal mammary artery stenosis PATHOLOGY General Features Etiology P.8:126

Neointimal hyperplasia Multifactorial response to mechanical vessel injury at the time of percutaneous coronary intervention Disruption of atherosclerotic plaque, endothelium, and intimal and medial layers May precipitate platelet adhesion, thrombus formation, and early graft loss Cascade of cytokine and growth factor release Expression of adhesion molecules Recruitment and infiltration of macrophages Vascular smooth muscle cells proliferation Migration and extracellular matrix deposition Progressive intimal thickening and superimposed atheromas can result in significant luminal narrowing and reduction in coronary blood flow, resulting in recurrent symptoms Accelerated atherosclerosis Progression of atherosclerosis in native coronary arteries proximal to grafts Due to lower blood flow through native coronary proximal segments Important when reoperation is considered Can cause proximal side branch ischemia CLINICAL ISSUES Presentation Most common signs/symptoms Angina recurs in 15-20% of patients during 1st year postop Subsequent recurrence ˜ 4% per year Natural History & Prognosis Saphenous veins grafts 10% of all grafts fail early (within 1 month) due to thrombotic occlusion 15% fail within 1 year due to intimal thickening 25% fail in subsequent years due to accelerated atherosclerosis Cumulative graft failure rate of 50% at 10 years post-op Arterial grafts Graft failure rate of 10% at 10 years Distal vasculature State of distal vasculature influences bypass graft patency Size of distal vascular bed Diameter of native coronary artery anastomosis Severity of distal atherosclerosis in native coronary artery Highest graft patency rates in Native vessels distal to graft with diameter > 1.5 mm Large distal vascular territory Free of atheroma obstructing > 25% of native distal vessel 786

Diagnostic Imaging Cardiovascular Rate of progression of disease in native vessels is highest in arterial segments with already established disease 3-6× higher rate of progression in grafted vs. nongrafted vessels Lesions in native vessels that are long (≥ 10 mm) and > 70% stenosed are at greatest risk of occluding Treatment Medical Antiplatelet therapy can reduce graft failure Lipid lowering can attenuate process of atherosclerosis Interventional Stenting is preferred over balloon angioplasty Drug-eluting stents are preferred over bare metal stents for saphenous veins graft interventions Surgical Redo bypass surgery DIAGNOSTIC CHECKLIST Consider Post-CABG atherosclerosis in patients with recurrence of angina postoperatively May occur in grafts May result from disease progression in native coronary arteries SELECTED REFERENCES 1. Hillis LD et al: Special Articles: 2011 ACCF/AHA Guideline for Coronary Artery Bypass Graft Surgery: executive summary: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Anesth Analg. 114(1):11-45, 2012 2. Robertson KE et al: Prevention of coronary in-stent restenosis and vein graft failure: does vascular gene therapy have a role? Pharmacol Ther. 136(1):23-34, 2012 3. Shukla N et al: Pathophysiology of saphenous vein graft failure: a brief overview of interventions. Curr Opin Pharmacol. 12(2):114-20, 2012 4. Sun Z et al: Coronary CT angiography: current status and continuing challenges. Br J Radiol. 85(1013):495-510, 2012 5. Şahinera L et al: Diagnostic accuracy of 16- versus 64-slice multidetector computed tomography angiography in the evaluation of coronary artery bypass grafts: a comparative study. Interact Cardiovasc Thorac Surg. 15(5):847-53, 2012 6. Sørensen R et al: Efficacy of post-operative clopidogrel treatment in patients revascularized with coronary artery bypass grafting after myocardial infarction. J Am Coll Cardiol. 57(10):1202-9, 2011 7. Pache G et al: Initial experience with 64-slice cardiac CT: non-invasive visualization of coronary artery bypass grafts. Eur Heart J. 27(8):976-80, 2006 8. Chiurlia E et al: Follow-up of coronary artery bypass graft patency by multislice computed tomography. Am J Cardiol. 95(9):1094-7, 2005 9. Frazier AA et al: Coronary artery bypass grafts: assessment with multidetector CT in the early and late postoperative settings. Radiographics. 25(4):881-96, 2005 10. Gasparovic H et al: Three dimensional computed tomographic imaging in planning the surgical approach for redo cardiac surgery after coronary revascularization. Eur J Cardiothorac Surg. 28(2):244-9, 2005 11. Marano R et al: Non-invasive assessment of coronary artery bypass graft with retrospectively ECG-gated four-row multi-detector spiral computed tomography. Eur Radiol. 14(8):1353-62, 2004 12. Salm LP et al: Blood flow in coronary artery bypass vein grafts: volume versus velocity at cardiovascular MR imaging. Radiology. 232(3):915-20, 2004 13. Langerak SE et al: Value of magnetic resonance imaging for the noninvasive detection of stenosis in coronary artery bypass grafts and recipient coronary arteries. Circulation. 107(11):1502-8, 2003 14. Bedaux WL et al: Assessment of coronary artery bypass graft disease using cardiovascular magnetic resonance determination of flow reserve. J Am Coll Cardiol. 40(10):1848-55, 2002 P.8:127

Image Gallery

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(Left) Coronary CTA in a 72-year-old man 10 years post CABG shows that the venous graft to the obtuse marginal branch has a noncalcified plaque causing stenosis of the proximal portion of the graft. The remainder of the graft is widely patent . (Right) Subsequent invasive angiogram confirms obstructive lesion in the proximal portion. Also, the remainder of the graft is widely patent . This patient subsequently underwent percutaneous coronary intervention to the graft.

(Left) Coronary CTA in a 78-year-old man with recurrent chest pain 15 years post CABG. shows mild to moderate diffuse atherosclerosis in the proximal portion of a vein graft to a diagonal branch and an obstructive stenosis in the proximal mid portion. Note 4 stents more distally, all of which appear patent. (Right) Subsequent corresponding invasive angiogram confirms diffuse disease in the proximal portion of the vein graft and an obstructive lesion in the proximal mid portion .

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(Left) Coronary CTA in a 63-year-old man with recurrent chest pain 9 years post CABG shows diffuse atherosclerosis scattered throughout this vein graft to an obtuse marginal branch. Note calcified and noncalcified plaques. Obstructive stenosis is noted in the mid portion. (Right) Subsequent corresponding invasive angiogram confirms an obstructive stenosis in the mid portion of the graft. Note that the plaque burden is underestimated on the invasive angiogram.

Myocardial Bridge Key Facts Terminology Congenital coronary anatomic variant in which a segment of epicardial coronary artery takes intramyocardial course Most common congenital coronary abnormality Most common location: Mid segment of left anterior descending (LAD) coronary artery Imaging Cardiac CT Epicardial coronary artery dives into myocardium and resurfaces distally into epicardial fat Curved multiplanar reformations may detect myocardium overlying coronary artery, particularly in LAD Intracoronary ultrasound Highly specific echolucent half-moon sign Top Differential Diagnoses Hypertrophic cardiomyopathy Cardiac tumor Coronary anomaly Clinical Issues Rarely clinically significant Certain bridges (long, deep) are controversially associated with ischemia β-blockers and calcium channel blockers are rarely needed Percutaneous coronary intervention can stabilize coronary artery lumen against muscular compression (very rarely) Coronary artery bypass graft if failure of percutaneous coronary intervention or coronary disease (extreme rarity)

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(Left) Coronary CTA curved multiplanar reformat shows a deep myocardial bridge affecting the mid segment of the left anterior descending coronary artery. The bridge is ˜ 20 mm long. The artery appears widely patent throughout. Note mitral valve replacement . (Right) Coronary CTA in the same patient using a cross-sectional image plane across the left anterior descending coronary artery confirms a deep left anterior descending coronary artery myocardial bridge passing into the interventricular septum.

(Left) Coronary CT curved multiplanar reformat shows a right coronary artery with a long intracavitary segment passing through the right ventricle. Such appearances are difficult to depict on invasive angiography. (Right) Coronary CTA in the same patient using a cross-sectional image plane across the right coronary artery confirms the intracavitary segment within the right ventricle. No stenosis of the right coronary artery was identified. P.8:129

TERMINOLOGY Definitions Congenital coronary anatomic variant in which a segment of epicardial coronary artery takes intramyocardial course IMAGING General Features Best diagnostic clue Coronary artery dives into and is covered by “bridge” of myocardium Location Most common = mid segment of left anterior descending coronary artery Left circumflex artery (40%), right coronary artery (20%) 790

Diagnostic Imaging Cardiovascular Morphology Most patients have single bridge Imaging Recommendations Best imaging tool Cardiac CT Epicardial coronary artery dives into myocardium and resurfaces distally into epicardial fat Curved multiplanar reformations may show myocardium overlying coronary artery CTA is more sensitive than invasive angiography for detection of bridges and intracavity coronary arteries Myocardial bridges are more frequently identified on CTA Often readers do not mention short shallow bridges as they are very common and not thought to be of clinical significance Intracoronary ultrasound shows highly specific echolucent half-moon sign DIFFERENTIAL DIAGNOSIS Hypertrophic Cardiomyopathy Asymmetric myocardial hypertrophy may mimic a bridge Cardiac Tumor May invade epicardial fat to engulf coronary arteries Coronary Anomaly Anomalous left main arising from right coronary artery and passing between great vessels may course through interventricular septum PATHOLOGY General Features Etiology 85% of coronary blood flow is in diastole Systolic lumen reduction seen on angiography is termed “milking” Because perfusion occurs during diastole, milking usually does not lead to reduced diastolic perfusion Impaired myocardial perfusion may occur in rare cases during stress Staging, Grading, & Classification Partial (˜ 65%) or complete “Touch-down” coronary artery or “loop”: Coronary artery touches myocardium but is not fully embedded Coronary artery may be intracavitary, mostly if bridge is in right atrium or (rarely) right ventricle Gross Pathologic & Surgical Features Intima of tunneled segment is thin Microscopic Features Systolic compression of bridged segment prevents deposition of lipid molecules leading to protection from atherosclerotic plaque Upstream shear wall stress predisposes to atherosclerosis upstream from bridge CLINICAL ISSUES Presentation Most common signs/symptoms Most asymptomatic Rarely angina, arrhythmia, or sudden death Clinical significance of myocardial bridge is related to its length and thickness, which determine magnitude of systolic compression Demographics Age Symptoms, if any, usually begin in 3rd decade Epidemiology Prevalence in angiographic series: 0.5-16%, much more common on CTA series Most common congenital coronary abnormality Associations Myocardial bridging is more common in young patients with hypertrophic cardiomyopathy Natural History & Prognosis Most patients are asymptomatic Treatment Medical: Rarely undertaken

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Diagnostic Imaging Cardiovascular β-blockers and calcium channel blockers can reduce external vessel compression by lowering systemic and intramural pressures Interventional: Very rarely undertaken Stents stabilize lumen against muscular compression Surgical: Extremely rarely undertaken Coronary artery bypass graft If unsuccessful percutaneous coronary intervention or significant coronary disease SELECTED REFERENCES 1. Nakanishi R et al: Myocardial bridging on coronary CTA: an innocent bystander or a culprit in myocardial infarction? J Cardiovasc Comput Tomogr. 6(1):3-13, 2012 2. Pursnani A et al: Coronary CTA assessment of coronary anomalies. J Cardiovasc Comput Tomogr. 6(1):48-59, 2012 3. Stanczyk A et al: Isolated myocardial bridge required by-pass grafting in 26-year-old syncopal woman. Rev Esp Cardiol (Engl Ed). 65(8):775-6, 2012 4. Nardi F et al: Variant angina associated with coronary artery endothelial dysfunction and myocardial bridge: a case report and review of the literature. Intern Med. 50(21):2601-6, 2011

Coronary Fistula Key Facts Terminology Abnormal connection between coronary artery branch and cardiac or vascular chambers without normal transition through capillary bed of myocardium May connect to pulmonary artery, coronary sinus, atria, or ventricles Synonyms: Coronary artery fistula, coronary arteriovenous fistula Imaging Large tortuous vessels with abnormal connection to cardiac chamber, pulmonary artery, or coronary venous system Normal origins of coronary artery from respective sinus of Valsalva Cardiac gated CTA is best imaging tool Ensure field of view selection in z-dimension includes entire pulmonary artery Delineates number, size, and anatomic course of feeding vessels Occasionally markedly enlarged and tortuous coronary arteries Often aneurysmal dilatation immediately proximal to drainage site Top Differential Diagnoses Anomalous coronary artery origin from pulmonary artery Coronary aneurysm Anomalous coronary artery Clinical Issues Often asymptomatic if smaller fistula without significant steal Prognosis is generally good, especially in smaller and moderate-sized fistula Treatment is often necessary but only in larger fistulas

(Left) Axial coronary CTA shows marked enlargement of the left main coronary artery 792

. Subsequent axial images

Diagnostic Imaging Cardiovascular showed communication with a round aneurysm and eventual drainage into the right atrium . (Right) Axial coronary CTA from the same patient shows ectasia of the left main coronary artery . It follows an anomalous course as it drains into the right atrium .

(Left) Lateral oblique volume-rendered and color-coded coronary CTA from the same patient shows the left coronary artery fistula (turquoise shaded) coursing towards the right atrium. (Left ventricle = purple; aorta = tan.) (Right) Coronal oblique maximum-intensity projection coronary CTA shows dilated and tortuous left main and left circumflex coronary arteries. The circumflex coronary artery drains anomalously into the dilated coronary sinus . P.8:131

TERMINOLOGY Synonyms Coronary artery fistula Coronary cameral fistula Abnormal direct connection between coronary artery and any cardiac chamber Coronary arteriovenous fistula (CAVF) Connection between coronary artery and pulmonary artery or coronary sinus or its tributaries Definitions Abnormal connection between coronary artery branch and cardiac or vascular chambers without normal transition through capillary bed of myocardium May connect to pulmonary artery, coronary sinus, atria, or ventricles Usually a congenital malformation; rarely develops as iatrogenic fistula after biopsy or as traumatic fistula CAVFs are differentiated from anomalous coronary artery origin from pulmonary artery (Bland-White-Garland syndrome, anomalous left coronary artery origin from pulmonary artery [ALCAPA], anomalous right coronary artery origin from pulmonary artery [ARCAPA]) Main difference is that in ALCAPA/ARCAPA abnormal vessel arise from pulmonary artery, and no separate ostium from the aorta is identified IMAGING General Features Best diagnostic clue Large tortuous vessels with abnormal connection to cardiac chamber, pulmonary artery, or coronary venous system Normal origins of coronary artery from respective sinus of Valsalva Location Connects high pressure system (coronary artery) with low pressure system Right ventricle (41%) Right atrium (26%) Pulmonary artery (17%) Coronary sinus (7%) Other (left atrium, left ventricle, or vena cava) 793

Diagnostic Imaging Cardiovascular Feeders originate from right coronary arterial system in 55%, left coronary system in 35%, and both systems or other arteries in 10% Within epicardial fat May have feeders from bronchial or mediastinal arteries entering epicardial fat space via space between pericardial reflection and great vessel wall Imaging Recommendations Best imaging tool Cardiac gated CTA Protocol advice Ensure field of view selection in z-dimension includes entire pulmonary artery Avoid incomplete visualization of fistula Typically cardiac CT starts at mid pulmonary arterial level Radiographic Findings Radiography Usually normal Rarely chamber enlargement CT Findings Cardiac gated CT is excellent test to delineate number, size, and anatomic course of feeding vessels Tortuous epicardial arterially enhancing vessels Often multiple feeders identified Occasional markedly enlarged and tortuous coronary arteries Drainage site is often identified Jet of arterial density contrast into receiving chamber (lower HU) or coronary sinus may be appreciated Often aneurysmal dilatation immediately proximal to drainage site Rarely enlarged cardiac chambers from left-to-right shunting MR Findings Findings similar to CT CT is superior in defining smaller feeders due to isovolumetric submillimeter spacial resolution and true volumetric imaging May detect late complications Late gadolinium enhancement imaging is highly sensitive for nontransmural myocardial infarction Echocardiographic Findings Enlarged feeding coronary artery Fistula drainage site demonstrates systolic and diastolic continuous turbulent flow pattern Microbubbles may enhance detection with color Doppler imaging Angiographic Findings Delineates size and detailed anatomy of fistulous vessels May potentially miss feeders that arise from unexpected locations Often difficult to define drainage into low-pressure cardiac system Enables transcatheter coil embolization DIFFERENTIAL DIAGNOSIS Bland-White-Garland Syndrome Anomalous coronary artery origin from pulmonary artery ALCAPA (typically) ARCAPA (occasionally) Large left-to-right shunt and steal phenomenon leading to symptoms in infancy Myocardial infarcts in infancy common Dyspnea and syncope during breast or bottle feeding Coronary Aneurysm No abnormal drainage into low-pressure chamber Absence of multiple feeders Anomalous Coronary Artery Abnormal origin of coronaries from sinus of Valsalva No abnormal feeders P.8:132

Other Causes of Coronary Artery Ectasia Kawasaki disease 794

Diagnostic Imaging Cardiovascular Usually affect multiple coronary arteries Coronary artery ectasia or aneurysm dominates No abnormal drainage Takayasu arteritis PATHOLOGY General Features Etiology Usually congenital malformation Persistence of embryonic intertrabecular spaces and sinusoids May be iatrogenic (right ventricular biopsy, pericardiocentesis, after septal myectomy, etc.) or due to other trauma May be complication of mycotic aneurysm CLINICAL ISSUES Presentation Most common signs/symptoms Often asymptomatic if smaller fistula without significant steal Depending on size, fistula may associate with Arrhythmia Dyspnea Congestive heart failure Endocarditis Angina pectoris if significant steal phenomenon Myocardial infarction Other signs/symptoms In pediatric population, often presents as cardiac murmur Lower to mid left sternal border Loud, superficial, and continuous murmur Maximal intensity of murmur relates to shunt entry site Demographics Epidemiology In larger angiographic series, incidence of coronary artery fistula detected during diagnostic coronary angiography is 0.1% Newer MDCT-based detection of fistulas suggests higher incidence of smaller fistulas, but to date there are no published larger series Natural History & Prognosis Generally good, especially in smaller and moderate-sized fistula Myocardial blood flow typically not compromised Rarely, serious complications Myocardial infarction Pulmonary hypertension Congestive heart failure Tamponade due to rupture of coronary artery fistula is reported Rarely spontaneous closure by thrombosis Treatment Treatment is necessary only in larger fistulas Antibiotic prophylaxis prior to dental, gastrointestinal, or genitourinary procedures due to risk of bacterial endocarditis Surgical ligation Carries risk of myocardial infarction Useful for large CAVF, multiple terminations, large aneurysm Catheter-based interventions Useful for proximal fistula, single drainage, older age, and absence of secondary findings requiring surgery (e.g., aortic stenosis, CABG) DIAGNOSTIC CHECKLIST Consider 3D volume-rendered images are helpful in delineating anatomy and identifying feeders If coronary fistula is suspected, ensure that scan range is extended superiorly to include aortic arch Otherwise, pulmonary fistula may be only partially visualized Occasionally, feeders from aortic arch are present 795

Diagnostic Imaging Cardiovascular SELECTED REFERENCES 1. Shriki JE et al: Identifying, characterizing, and classifying congenital anomalies of the coronary arteries. Radiographics. 32(2):453-68, 2012 2. Díaz-Zamudio M et al: Coronary artery aneurysms and ectasia: role of coronary CT angiography. Radiographics. 29(7):1939-54, 2009 3. Zenooz NA et al: Coronary artery fistulas: CT findings. Radiographics. 29(3):781-9, 2009 4. Cowles RA et al: Bland-White-Garland syndrome of anomalous left coronary artery arising from the pulmonary artery (ALCAPA): a historical review. Pediatr Radiol. 37(9):890-895, 2007 5. Gulati GS et al: Utility of multislice computed tomography in the diagnosis of a right coronary artery fistula to the right atrium. J Postgrad Med. 53(3):191-2, 2007 6. Iwasawa Y et al: Cardiac tamponade due to rupture of coronary artery fistulas with a giant aneurysm containing a free floating ball thrombus: a case report. J Cardiol. 50(1):71-6, 2007 7. Kharouf R et al: Transcatheter closure of coronary artery fistula complicated by myocardial infarction. J Invasive Cardiol. 19(5):E146-9, 2007 8. Latson LA: Coronary artery fistulas: how to manage them. Catheter Cardiovasc Interv. 70(1):110-6, 2007 9. Oncel D et al: An Aneurysmal Left Circumflex Artery-to-Right Atrium Fistula in a Patient with Ischemic Symptoms: Accurate Diagnosis with Dual-Source CT Angiography. Cardiovasc Intervent Radiol. 2007 10. Gowda RM et al: Coronary artery fistulas: clinical and therapeutic considerations. Int J Cardiol. 107(1):7-10, 2006 11. Luo L et al: Coronary artery fistulae. Am J Med Sci. 332(2):79-84, 2006 12. Takahashi Y et al: Successful surgical treatment of a mycotic right coronary artery aneurysm complicated by a fistula to the right atrium. Jpn J Thorac Cardiovasc Surg. 53(12):661-4, 2005 13. Friedman WF et al: Diseases of the heart, pericardium and pulmonary vascular bed. In Braunwald E et al: Heart Disease. 6th ed. Philadelphia: W. B. Saunders. 1505-91, 2001 14. Vavuranakis M et al: Coronary artery fistulas in adults: incidence, angiographic characteristics, natural history. Cathet Cardiovasc Diagn. 35(2):116-20, 1995 P.8:133

Image Gallery

(Left) Oblique volume-rendered cardiac CTA shows enlarged tortuous branches from the left anterior descending and right coronary arteries entering the right ventricle (RV) at its anterior surface, consistent with a coronary cameral fistula. (Right) Axial cardiac CT shows tortuous enlarged coronary artery branches at the RV anterior free wall connecting abnormally to the RV lumen . Note high-density arterial contrast entering the RV. Note anomalous circumflex artery .

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(Left) Axial coronary CTA shows an enlarged left main coronary artery arising normally from the aorta (Ao). Note anomalous and tortuous vessel arising from the proximal left anterior descending artery, which courses superiorly to drain into the main pulmonary artery. (Right) Axial MRA in the same patient shows a spin-dephasing flow void jet at the site of the anomalous connection between the left anterior descending and main pulmonary arteries.

(Left) Axial oblique maximum-intensity projection image shows an ectatic left anterior descending artery . An abnormal connection is present between the left anterior descending artery and the right ventricle . The origin of the left main coronary artery is from the left sinus of Valsalva . (Right) Modified short-axis coronary CTA from the same patient shows the enlarged left anterior descending coronary artery and the fistulous connection to the right ventricle.

Section 9 - Heart Failure Approach to Heart Failure Approach to Heart Failure Lowie M. R. Van Assche, MD John D. Grizzard, MD Raymond J. Kim, MD Introduction Heart failure (HF) is defined as “a pathophysiological state in which an abnormality of cardiac function is responsible for failure of the heart to pump blood at a rate commensurate with the requirements of the metabolizing tissues.”

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Diagnostic Imaging Cardiovascular The cardinal manifestations of HF are dyspnea and fatigue, which may limit exercise tolerance, and fluid retention, which may lead to pulmonary congestion and peripheral edema. Prevalence HF is increasing in prevalence, resulting in what some have termed an epidemic. Nearly 6 million patients in the United States are estimated to have heart failure, and every year 670,000 are newly diagnosed with HF. An estimated 23 million people are affected by HF worldwide, with the prevalence of symptomatic HF ranging within 0.4-2%. HF prevalence increases with age and is more common in men. Importance HF causes more deaths than all forms of cancer combined. The 5-year mortality rate for a patient diagnosed with HF is 50%. Pathophysiology Left vs. Right Heart Failure Left HF refers to the signs and symptoms of elevated pressure and congestion in the pulmonary veins and capillaries, as well as low systemic cardiac output. Right HF refers to the signs and symptoms of elevated pressure and congestion of the systemic veins and capillaries, as characterized by jugular vein engorgement and hepatic congestion. Systolic vs. Diastolic Heart Failure In systolic dysfunction, the left ventricle appears large, dilated, and eccentrically hypertrophied, and the cardiac output is limited by impaired systolic ejection fraction. In diastolic dysfunction, the left ventricle typically appears thickened, with a normal to small cavity in which filling is limited because of abnormal left ventricular compliance. Treatment The recently updated American College of Cardiology/American Heart Association Heart Failure Guidelines (2013) provide detailed information regarding the management and prevention of HF. Imaging/Assessment Techniques A variety of techniques are available for assessing patients with HF, and different clinical circumstances will largely determine which test is most appropriate for a given clinical situation. Electrocardiogram An electrocardiogram can be used to detect many myocardial abnormalities, such as arrhythmias, previous myocardial infarction, or ventricular hypertrophy. When an electrocardiogram is completely normal, heart failure from structural heart disease is unlikely, but its positive predictive value is low. Chest Radiograph Chest radiography is used to determine the overall cardiac size, detect pulmonary vascular congestion, and look for evidence of failure, such as pulmonary edema or pleural effusions. It is also used to exclude other causes of dyspnea (e.g., pneumonia, lung carcinoma). Although echocardiography has replaced the chest radiograph as a method to determine heart dimensions and functioning, radiography is often used to monitor acutely ill patients and their responses to therapy. In patients with decompensated HF, chest radiography may show cephalization of pulmonary blood flow, interstitial or alveolar edema, effusions, or Kerley B lines. Clearing of these findings is indicative of a response to therapy. Echocardiography Transthoracic echocardiography is a fast, simple, safe, and effective tool for assessing cardiac structure and function. Echocardiography, including 2D transthoracic ultrasound and Doppler, is strongly recommended as a first-line technique for imaging patients with new-onset HF. Favorable aspects of echocardiography include its widespread availability, the lack of radiation, and the use of real-time imaging. Echocardiography provides extensive information about the etiology and severity of HF as it can accurately assess chamber dimensions, biventricular function, valve stenosis or regurgitation, and diastolic function (filling pressures and patterns). When assessing a patient with new-onset HF, the presence of four-chamber dilatation suggests a nonischemic etiology, whereas regional wall motion abnormalities may suggest an ischemic etiology. Other diagnoses may present with classic findings. For example, cardiac amyloidosis may present with biventricular thickening, small chamber size, restrictive physiology, and “sparkling” echogenicity. Similarly, hypertrophic cardiomyopathy can present with mitral systolic anterior motion of the mitral valve, outflow tract obstruction, and asymmetric septal hypertrophy. Use of echocardiography is reasonable in patients with ST-segment elevation myocardial infarction to reevaluate cardiac function during recovery when results are utilized to guide therapy (class 2a, level C recommendation). Single-Photon Emission Computed Tomography Single-photon emission computed tomography (SPECT) is not primarily used to determine left ventricular systolic function unless the relevant parameters are quantified from a myocardial perfusion assessment. Radionuclide Ventriculography

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Diagnostic Imaging Cardiovascular Radionuclide ventriculography (RNV) is an alternative that may be used to evaluate cardiac function. RNV is a planar technique, and it can be useful for the assessment of volumes in patients with significant wall motion abnormalities or distorted geography. Quantitative RNV measurements are highly reproducible, and serial RNV measurements of left ventricular volumes have been used to track the efficacy of therapies in patients with HF. Today, RNV is a technique that is less commonly performed than in the past. Computed Tomography Computed tomography (CT) can provide an accurate assessment of cardiac structure and function. This technique has very high spatial resolution and is particularly useful for noninvasive evaluation of the coronary arteries. Coronary CT is more difficult when P.9:3 patients have high heart rates or in the presence of significant calcium in the coronaries. One advantage of CT over echocardiography is the ability to detect pericardial calcification, as may be seen with constrictive pericarditis. Currently, there are limited data on the use of CT in patients with new-onset HF. However, CT is often used to exclude other etiologies for dyspnea, such as pulmonary embolism. Cardiac Catheterization Cardiac catheterization can accurately assess the overall cardiac function and hemodynamics and serves as the gold standard for the evaluation of the suspected obstructive coronary artery disease (CAD). It is also considered the gold standard for the evaluation of many valvular disorders (e.g., aortic stenosis, pulmonic stenosis). Coronary catheterization should be performed in patients presenting with HF who have angina or significant ischemia unless the patient is not eligible for revascularization of any kind (class 1, level B recommendation). Coronary catheterization is reasonable for patients presenting with HF who have angina who have not had evaluation of their coronary anatomy and who have no contraindications to coronary revascularization (class 2a, level C recommendation). Coronary catheterization is also reasonable in patients with new-onset HF without angina but with known or suspected CAD (class 2a, level C recommendation). Magnetic Resonance Imaging Magnetic resonance (MR) imaging provides high-resolution images of cardiac function and structure. Because of its accuracy and reproducibility in measuring left ventricular volumes and structure, it has become the reference standard for volumetric analysis of cardiac function. Studies over the last decade have supported the use of MR in patients with new-onset HF. In addition to its excellent depiction of cardiac function, MR can also assess myocardial perfusion, viability, and fibrosis, which can be very useful in identification of the etiology, and facilitate prognosis in patients with HF. Determining the Etiology of Heart Failure In patients with HF, it is important to determine the etiology in order to provide appropriate treatment and prognostic information. Even when patients still have normal systolic function, early diagnosis may allow for preventative measures that can change the natural history of the disease. The basic differentiation between ischemic and nonischemic cardiomyopathies is important and useful because this classification directly affects patient management. Late Gadolinium Enhancement MR Late gadolinium enhancement (LGE) is useful for detecting acute and chronic myocardial infarction, predicting functional improvement after revascularization, and characterizing an extensive array of nonischemic cardiomyopathies. The use of LGE in the setting of heart failure is based on the understanding that rather than simply measuring viability, this technique also reveals the presence and patterns of hyperenhancement, which yield significant additional information. A systematic approach for interpreting LGE MR in patients with heart failure has recently been proposed. This approach is based on four steps: Step 1: Assess the severity and regionality of left ventricular dysfunction, chamber size, wall thickness, and valvular function using cine cardiac MR. Step 2: Determine the presence or absence of hyperenhancement. In patients with severe ischemic cardiomyopathy, almost all patients have prior myocardial infarction. This means that if patients with severe cardiomyopathy do not have hyperenhancement, the diagnosis of nonischemic cardiomyopathy should be strongly considered. Common conditions in which hyperenhancement is often absent include idiopathic dilated, alcoholic, Takotsubo, and peripartum cardiomyopathies. Step 3: If hyperenhancement is present, the location and distribution of hyperenhancement should be classified as a CAD or non-CAD pattern. Understanding the physiology of ischemic injury, which progresses as a wavefront phenomenon from subendocardium to epicardium, is fundamental to distinguishing between the these patterns. Hyperenhancement patterns that spare the subendocardium and are limited to the mid or epicardial portion of the left ventricle are generally considered non-CAD patterns.

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Diagnostic Imaging Cardiovascular Step 4: If hyperenhancement is present in a non-CAD pattern, further classification is possible. There are now abundant data indicating that certain nonischemic cardiomyopathies have a predilection to produce specific scar patterns. For example, in patients with left ventricular hypertrophy, the presence of midwall hyperenhancement in one or both junctions of the interventricular septum with the right ventricular free wall is highly suggestive of hypertrophic cardiomyopathy, whereas midwall or epicardial hyperenhancement in the inferolateral wall is consistent with Anderson-Fabry disease. It appears that a broad stratification into a limited number of common LGE MR patterns is possible. Conclusion HF is a growing clinical problem. MR provides a direct assessment of myopathic processes with the use of delayedenhancement imaging, and an integrated approach using cardiac MR can often determine the etiology of cardiomyopathies in patients with this condition. Selected References 1. Patel MR et al: 2013 ACCF/ACR/ASE/ASNC/SCCT/SCMR Appropriate Utilization of Cardiovascular Imaging in Heart Failure: A Joint Report of the American College of Radiology Appropriateness Criteria Committee and the American College of Cardiology Foundation Appropriate Use Criteria Task Force. J Am Coll Cardiol. 61(21):2207-31, 2013 2. Kim YJ et al: The role of cardiac MR in new-onset heart failure. Curr Cardiol Rep. 13(3):185-93, 2011 3. Mahrholdt H et al: Delayed enhancement cardiovascular magnetic resonance assessment of non-ischaemic cardiomyopathies. Eur Heart J. 26(15):1461-74, 2005 P.9:4

Image Gallery

(Left) AP upright radiograph shows a dilated cardiac silhouette with moderate-sized bilateral pleural effusions , lower lung and retrocardiac atelectasis , and vascular congestion due to pulmonary edema. (Right) Axial CTA for pulmonary embolism detection shows that while no emboli are seen, findings of left ventricular failure are present, and prominent septal lines and bilateral effusions are evident.

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(Left) Vertical long-axis (2-chamber) coronary CTA image shows occlusion of the left anterior descending coronary artery , with resultant apical infarction and aneurysm formation , which caused the patient's heart failure. (Right) Four-chamber view cine (top) and late gadolinium enhancement (LGE) (bottom) MR images show findings of prior apical infarction evident as thinning on the cine image and as abnormal enhancement on the LGE image. The apex was dyskinetic as well, further impairing cardiac output.

(Left) Short-axis MR cine images in diastole (left) and systole (right) demonstrate an area of wall thinning involving the anterior and anteroseptal walls . Note the lack of change between systole and diastole, indicative of impaired wall motion. (Right) Short-axis LGE image shows an area of prior infarction involving the anterior and anteroseptal walls. Note the subendocardial predominance of enhancement characteristic of a coronary artery disease pattern. P.9:5

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(Left) Four-chamber view late gadolinium enhancement (LGE) image from a patient with dilated nonischemic cardiomyopathy shows a “midwall stripe” pattern of uptake . This is clearly different than an ischemic (subendocardial) pattern, which allows this entity to be differentiated from ischemic cardiomyopathy. (Right) Shortaxis late gadolinium enhancement (LGE) image (top) and LVOT LGE view (bottom) of a patient with viral myocarditis show epicardial enhancement in a noncoronary distribution.

(Left) Short-axis LGE MR image of a patient with the asymmetric septal variant of hypertrophic cardiomyopathy demonstrates abnormal enhancement of the right ventricular insertion site upon the septum. This pattern is common in hypertrophic cardiomyopathy, and clearly differs from a coronary injury pattern. (Right) Short-axis LGE MR image from a patient with amyloidosis shows the typical diffuse subendocardial pattern of enhancement seen in this disorder .

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(Left) Four-chamber view LGE MR image from a patient with cardiac sarcoidosis shows patchy foci of abnormal enhancement in the septum and lateral wall in a noncoronary artery pattern. (Right) Short-axis LGE MR image of a patient with Fabry disease shows characteristic concentric hypertrophy as well as abnormal midwall enhancement of the inferolateral basal wall with subendocardial sparing, which differentiates this from the coronary artery disease pattern.

Right Heart Failure Right Heart Failure Lowie M. R. Van Assche, MD John D. Grizzard, MD Raymond J. Kim, MD Key Facts Terminology Right ventricular (RV) dysfunction that results in 1 or both of the following Inadequate RV systolic forward flow to maintain normal cardiac output Diastolic filling impairment that results in abnormally high venous filling pressures Most often due to either left heart failure or pulmonary hypertension Imaging Echocardiography is best screening tool; MR provides best noninvasive evaluation of RV function Right heart catheterization is best differentiator of causes of pulmonary hypertension CXR: Signs of underlying PH, including dilated main and hilar pulmonary arteries, may be seen on frontal and lateral views RV enlargement is demonstrated as increased filling of retrosternal clear space on lateral view CT/MR: Contrast refluxing into enlarged hepatic veins indicates diastolic impairment or tricuspid regurgitation Cine MR: Gold standard for assessing RV volumes and RV ejection fraction LGE imaging: Shows enhancement at sites of RV insertion in septum Acute right heart failure may be seen with massive pulmonary emboli Top Differential Diagnoses Isolated left heart failure Constrictive pericarditis Atrial septal defects/partial anomalous pulmonary venous return Pulmonic stenosis Noncardiogenic edema

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(Left) Posteroanterior (left) and lateral (right) radiographs of a patient with idiopathic pulmonary arterial hypertension (PAH) demonstrate marked enlargement of the main and hilar pulmonary arteries. Note that the heart size is normal on the frontal image and that the significant right ventricular (RV) enlargement is apparent only on the lateral view. (Right) Coronal CECT of PAH and RV overload demonstrates enlarged pulmonary arteries and reflux of contrast into the hepatic veins .

(Left) Axial CECT of a patient with PAH shows septal bowing to the left , indicative of elevated RV pressure. Note also the hypertrophy of the RV free wall . (Right) Four-chamber view MR cine (top) and LGE image (bottom) of a patient with biventricular enlargement and failure due to ischemic cardiomyopathy show extensive abnormal enhancement of the left ventricular apex , consistent with prior infarction. Most cases of right heart failure result from left heart failure. P.9:7

TERMINOLOGY Abbreviations Right heart failure (RHF) Definitions Right ventricular (RV) dysfunction that results in either inadequate RV systolic forward flow to maintain normal cardiac output or diastolic filling impairment leading to abnormally high venous filling pressures, or both The “forward” and “backward” components of RHF often coexist but manifest differently Forward failure manifests as decreased RV ejection fraction (RVEF), increased pulmonary circulation time, decreased pulmonary artery (PA) velocity Backward failure results in peripheral edema, hepatic congestion, ascites, pleural effusions 804

Diagnostic Imaging Cardiovascular Most often due to either left heart failure (LHF) or pulmonary hypertension (PH) Often results from PH resulting in maladaptive RV hypertrophy and later failure Cor pulmonale = RV failure due to pulmonary parenchymal or vascular disease Acute RHF may be seen with massive pulmonary emboli RHF occurring without LHF is identified when abnormally high right atrial pressures are accompanied by normal capillary wedge pressures IMAGING General Features Best diagnostic clue Impaired RV function (primarily assessed by determination of RVEF) MR imaging is gold standard for measurement of RV function, volumes, and mass Alternatives include echocardiography and nuclear angiographic techniques Size Abnormal RV enlargement is recognized when RV diameter > corresponding left ventricular measurement at same level Morphology Increase in RV sphericity is often seen as RV enlargement progresses Radiographic Findings Radiography RV is not usually evident on frontal radiograph Widening of vascular pedicle is often apparent, indicating central venous engorgement Azygos vein may become prominent RV enlargement is demonstrated as increased filling of retrosternal clear space on lateral view Signs of underlying PH, including dilated main and hilar PAs, may be seen on frontal and lateral views As RHF and LHF frequently coexist and are often causally related, signs of LHF may be present Cardiomegaly, vascular redistribution, and interstitial and alveolar edema CT Findings NECT Coexisting or causative lung disease (severe fibrosis, emphysema, etc.) is usually readily apparent Dilated inferior vena cava, ascites, peripheral edema, and anasarca may be seen Retrospectively gated cardiac CT can demonstrate decreased RV function Enlargement of right-sided structures (RV, right atrium, and systemic veins) is often seen with systolic dysfunction Contrast refluxing into enlarged hepatic veins may indicate diastolic impairment or tricuspid regurgitation Underlying PH (when present) causes dilatation of main (> 29 mm) and hilar PAs CT pulmonary angiography may show pulmonary emboli &/or findings suggestive of chronic pulmonary thromboembolic disease MR Findings MRA Chronic PH results in dilatation of main and hilar PAs MR cine RV function is typically assessed by volumetric analysis using stack of short-axis cine SSFP images from base to apex Cine MR is gold standard for assessing RV volumes and RVEF Impaired diastolic function can be evaluated using through-plane flow studies of tricuspid and mitral valves Radius of septal curvature during systole can be used to estimate relative PA and aortic pressures Progressive flattening is seen with greater degrees of PH Associated tricuspid and pulmonic regurgitation can be evaluated Right atrial pressure is estimated by size of inferior vena cava Delayed enhancement Enhancement is often noted at sites of RV insertion in septum Normal RV functional parameters RV end-diastolic volume: 138 ± 40 mL RV end-systolic volume: 54 ± 21 mL RV free wall mass: 46 ± 11 gm (26 ± 5 gm/m 2) RVEF: 61% ± 7% RV stroke volume: 84 ± 24 mL (46 ± 8 mL/m 2) Right atrial pressure is estimated by size of inferior vena cava Small (< 1.5 cm): 0-5 mm Hg 805

Diagnostic Imaging Cardiovascular Normal (1.5-2.5 cm): 5-15 mm Hg Dilated (> 2.5 cm): 15-20 mm Hg Dilated and enlarged hepatic veins: > 20 mm Hg Echocardiographic Findings Echocardiogram Can assess RV, left ventricular, and valvular function in patients with satisfactory acoustic windows Good screening technique for PH RV systolic pressure (which reflects PA pressure) is calculated by measuring tricuspid regurgitant jet velocity Decreased RV outflow tract acceleration time Dilated inferior vena cava and hepatic veins Pulsed Doppler P.9:8

Tricuspid plane systolic excursion and peak velocity of D wave correlate well with RVEF Angiographic Findings Conventional right heart catheterization (RHC) is gold standard for diagnosis of PH PH: Systolic pressure > 25 mm Hg (at rest), > 30 mm Hg (at exercise) PA hypertension (PAH) is present when pulmonary vascular resistance is elevated (> 3.0 Wood units), and pulmonary capillary wedge pressure (PCWP) < 15 mm Hg Left ventricular dysfunction is evaluated by PCWP measurement Imaging Recommendations Best imaging tool Echocardiography is the best screening tool MR provides the best noninvasive evaluation of RV function RHC is the best differentiator of causes of PH DIFFERENTIAL DIAGNOSIS Isolated Left Heart Failure Typically, pulmonary symptoms predominate Acute or chronic left heart dysfunction may result in RHF Constrictive Pericarditis Produces similar clinical findings (dilated inferior vena cava, leg edema, hepatic congestion) Distinction from RHF can be made with MR Recognized by abnormal pericardial thickening (> 4 mm) and adhesions between layers “Septal bounce” noted on cine imaging suggests altered hemodynamics Real-time cine imaging during deep inspiration showing septal inversion directly demonstrates abnormal hemodynamics Atrial Septal Defects/Partial Anomalous Pulmonary Venous Return Typically, produce enlargement of right atrium and RV, but function is preserved Pulmonary Stenosis Produces RV hypertrophy and PA enlargement Left PA is often larger than right PA due to direction of flow jet Noncardiogenic Edema End-stage liver disease with ascites and pleural effusions, renal disease PATHOLOGY General Features Etiology Most common cause is LHF (myocardial infarction, ischemic cardiomyopathy, etc.) Pulmonary hypertension can be subdivided into PAH: Due to intrinsic pulmonary vascular disease (primary PH) or pulmonary embolic disease (acute or chronic) PH: Due to lung disease (COPD, sarcoid, interstitial fibrosis, etc.) Volume overloads: Valvular dysfunction (tricuspid regurgitation, pulmonary insufficiency) or shunts (atrial septal defects, partial anomalous pulmonary venous return) Primary RV cardiomyopathy/infarction Staging, Grading, & Classification Class I: No limitation during ordinary activity Class II: Slight limitation by shortness of breath ± fatigue during moderate exertion 806

Diagnostic Imaging Cardiovascular Class III: Symptoms with minimal exertion that interfere with normal daily activity Class IV: Inability to carry out physical activity; patients typically have marked neurohumoral activation, muscle wasting, and reduced oxygen consumption Gross Pathologic & Surgical Features RV is often dilated and hypertrophied May see hypertrophy of right atrium CLINICAL ISSUES Presentation Most common signs/symptoms Fatigue, lethargy, and dyspnea Lower extremity edema, ascites, and weight gain are seen in chronic RHF Symptoms reflect underlying illness precipitating RHF (COPD, pulmonary embolism, etc.) Other signs/symptoms Loud P2 on auscultation indicates PH Demographics Epidemiology Commonly the result of LHF Major source of morbidity and mortality Natural History & Prognosis Outcome of RHF most often depends on prognosis of underlying left heart dysfunction or precipitating pulmonary disease Treatment Patients with LHF: Standard CHF therapy with diuretics, afterload reduction, ACE inhibitors, β-blockers Patients with cor pulmonale: Treatment of underlying lung disease, hypoxia (oxygen therapy) Patients with PAH: Endothelin receptor antagonists (bosentan), phosphodiesterase inhibitor (sildenafil), prostacyclin analogues, inotropes SELECTED REFERENCES 1. Mahmud M et al: Right ventricular failure complicating heart failure: pathophysiology, significance, and management strategies. Curr Cardiol Rep. 9(3):200-8, 2007 2. Voelkel NF et al: Right ventricular function and failure: report of a National Heart, Lung, and Blood Institute working group on cellular and molecular mechanisms of right heart failure. Circulation. 114(17):1883-91, 2006 3. Braunwald E et al: Heart Disease: A Textbook of Cardiovascular Medicine. 7th ed. Philadelphia: W. B. Saunders. 1807-42, 2005 P.9:9

Image Gallery

(Left) Short-axis MR systolic cine image of a patient with severe pulmonary hypertension associated with extensive fibrotic lung disease (cor pulmonale) shows flattening of the septum , indicating equilibration of pulmonary and systemic pressures. The radius of septal curvature on MR cine images correlates with pulmonary artery pressures. (Right) Short-axis late gadolinium enhancement (LGE) image (same patient) shows typical abnormal enhancement at the RV insertion sites on the septum . 807

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(Left) Axial CECT shows extensive pulmonary emboli in the central pulmonary arteries bilaterally (top). A more inferior image (bottom) shows straightening of the septum, indicating elevated RV pressure. Filling defects are seen in the RV and right atrium , consistent with venous emboli in transit. (Right) Four-chamber view MR cine (left) shows right atrial and RV enlargement and the responsible atrial septal defect . In-plane flow study (right) confirms abnormal flow through the defect.

(Left) Short-axis MR cine of a patient with constrictive pericarditis shows marked dilatation of the hepatic veins and inferior vena cava as well as ascites . Constrictive pericarditis can closely mimic many of the findings of right heart failure. (Right) Four-chamber view T1WI (top), and LGE (bottom) images of a patient with constrictive pericarditis show pericardial thickening evident of the T1 image. The thickened pericardium shows intense enhancement on the LGE image.

Left Heart Failure Key Facts Terminology Pathophysiologic state in which the left ventricle is unable to pump blood at a rate sufficient to meet oxygen needs of end organs Imaging Radiography Enlarged cardiac silhouette with pulmonary edema and pleural effusions Increased pulmonary artery to bronchus ratio Kerley B lines CT 808

Diagnostic Imaging Cardiovascular Enlarged hilar nodes Thickening of interlobular septa Bronchovascular bundle thickening Ground-glass opacities CTA May demonstrate underlying cause of congestive heart failure MR cine Decreased stroke volume and ejection fraction Late gadolinium enhancement MR Used for identifying viable and nonviable myocardium May demonstrate ischemic or nonischemic etiology of congestive heart failure Echocardiography Most useful diagnostic test in evaluation of heart failure per American College of Cardiology (ACC)/American Heart Association (AHA) guidelines Findings vary depending on etiology Top Differential Diagnoses Ischemic cardiomyopathy Nonischemic cardiomyopathy Noncardiogenic pulmonary edema Pericardial effusion

(Left) PA radiograph of patient with left heart failure shows cardiomegaly (with an enlarged cardiothoracic ratio), cephalization of pulmonary blood flow, and interstitial edema. Kerley B lines and small pleural effusions are also apparent. (Right) Coronal reformat CECT image in a patient with left ventricular (LV) failure shows prominent septal lines in the upper lobes bilaterally , demarcating the secondary pulmonary lobules. These reflect the presence of interstitial edema with lymphatic distention.

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(Left) Axial CECT in a patient with LV failure demonstrates an abnormal artery/bronchus ratio , with the arterial branch clearly larger than the adjacent bronchus. The faint ground-glass opacities noted represent alveolar edema. Pleural effusions are also noted . (Right) Axial CECT shows bilateral pleural effusions, interstitial edema with bronchial cuffing , and dilated left ventricle with subendocardial rest perfusion defect in a patient with LV failure due to ischemic cardiomyopathy. P.9:11

TERMINOLOGY Synonyms Left ventricular (LV) failure Congestive heart failure (CHF) CHF often used interchangeably with LV failure, but LV failure should be differentiated from biventricular failure and right ventricular (RV) failure Definitions Physiologic state in which the left ventricle is unable to pump at rate necessary to meet oxygen consumption needs of end organ tissue Systolic dysfunction: Decrease in myocardial contractility Diastolic heart failure: LV end-systolic volume and stroke volume are preserved; there is, however, an abnormal decrease in LV diastolic distensibility IMAGING General Features Best diagnostic clue Cardiomegaly with pulmonary venous hypertension (Kerley lines, redistribution, pulmonary edema, effusion) on chest radiograph Radiographic Findings Radiography Chest radiograph demonstrates enlarged cardiac silhouette with pulmonary edema and possibly pleural effusions Cardiomegaly is recognized by abnormal cardiothoracic ratio (> 0.50) Cardiothoracic ratio = transverse diameter of cardiac silhouette divided by transverse diameter of inner ribcage at level of diaphragms Poor definition of vessel margins indicates interstitial edema Rough correlation of pulmonary capillary wedge pressure with chest radiograph findings Pulmonary venous redistribution (larger apical arteries, smaller basal arteries): Pulmonary venous pressure = 18-23 mm Hg Kerley B lines: Pulmonary venous pressure = 20-25 mm Hg Alveolar edema with “butterfly” or “batwing” distribution ± effusions: Pulmonary venous pressure > 25 mm Hg Azygos, superior vena cava, and inferior vena cava distention if biventricular or RV failure CT Findings 810

Diagnostic Imaging Cardiovascular NECT Readily apparent cardiomegaly Coronary calcifications signifying coronary artery disease may be seen in ischemic cardiomyopathy Increased pulmonary artery to bronchus ratio Mildly enlarged hilar nodes HRCT Thickening of interlobular septa Bronchovascular bundle thickening Ground-glass or airspace opacities, most prominent in dependent portions of lungs Cardiac gated CTA May demonstrate underlying cardiac cause of failure Myocardial infarction (thinning, calcification, fatty metaplasia, subendocardial perfusion defects) LV dilatation indicating dilated cardiomyopathy Mitral valve disorders Coronary artery disease MR Findings Functional findings are similar to those of echocardiography, but MR is more precise in quantifying myocardial functional parameters (i.e., stroke volume, ejection fraction) Late gadolinium enhancement (LGE) MR may also be used to identify viable and nonviable myocardial tissue Viability on LGE MR may be used to predict response to β-blocker therapy and revascularization LGE MR can often distinguish dilated nonischemic cardiomyopathy (NICM) from ischemic cardiomyopathy (ICM) Patients with significantly reduced left ventricular ejection fraction (< 35%) due to ICM will almost always have discernible foci of abnormality on LGE MR Patients with dilated NICM will usually show normal LGE MR pattern (60%) or a mid-wall stripe pattern clearly different from ICM (28-30%) May demonstrate and characterize other nonischemic causes of LV failure Hypertrophic cardiomyopathy Infiltrative cardiomyopathies (e.g., amyloid) Myocarditis Takotsubo disease Echocardiographic Findings Echocardiogram Echocardiography with Doppler flow imaging is considered the most useful diagnostic test in evaluation of heart failure patients (per ACC/AHA Chronic Heart Failure Evaluation and Management Guidelines) Determination of LV function Abnormalities of pericardium, myocardium, and valves Findings vary depending on etiology Decreased ejection fraction with systolic dysfunction Decreased compliance with diastolic dysfunction Nuclear Medicine Findings Radionuclide ventriculography is alternative diagnostic test to evaluate LV function (per ACC/AHA Chronic Heart Failure Evaluation and Management Guidelines) Imaging Recommendations Best imaging tool MR is the best means of distinguishing ischemic from nonischemic cardiomyopathy DIFFERENTIAL DIAGNOSIS Etiology of Left Heart Failure Dilated cardiomyopathy (ischemic vs. nonischemic) Restrictive Constrictive Infiltrative disease P.9:12

Noncardiogenic Pulmonary Edema Acute respiratory distress syndrome 811

Diagnostic Imaging Cardiovascular Neurogenic pulmonary edema May closely resemble CHF, but heart size is usually normal, and effusions are usually absent Pericardial Effusion Enlarged cardiac silhouette on chest radiograph May have clear lungs PATHOLOGY General Features Etiology Causes of CHF Myocardial ischemia/infarction Nonischemic cardiomyopathy Myocarditis Arrhythmias Congenital heart disease High output states Anemia, valvular heart disease, papillary muscle rupture Vein of Galen aneurysm/other congenital arteriovenous fistulae in neonates Genetics Some component of inheritance for dilated cardiomyopathy and hypertrophic cardiomyopathy Staging, Grading, & Classification New York Heart Association (NYHA) classification Class I: No limitation during ordinary activity Class II: Comfortable at rest; slight limitation by shortness of breath, palpitation, dyspnea, or angina during ordinary physical activity Class III: Comfortable at rest; symptoms with minimal exertion that interfere with normal daily activity Class IV: Unable to carry out any physical activity; patients typically have marked neurohumoral activation, muscle wasting, and reduced peak oxygen consumption Framingham classification requires 2 major criteria or 1 major and 2 minor criteria for diagnosis of CHF Major criteria Cardiomegaly on radiograph Pulmonary edema Jugular vein distention Hepatojugular reflux Rales Nocturnal dyspnea S3 gallop Elevated central venous pressure > 16 cm H2O Circulation time of 25 seconds Weight loss with treatment (≥ 4.5 kg per 5 treatment days) Minor criteria Pleural effusion Bilateral ankle edema Dyspnea with ordinary activity Hepatomegaly Decreased vital capacity Tachycardia (≥ 120 bpm) Nocturnal cough Gross Pathologic & Surgical Features Areas of infarcted myocardium in ischemic systolic dysfunction Variety of other pathologies in alternative types of cardiac dysfunction Microscopic Features Infarcted areas of myocardium in ischemic heart failure Infiltrating diseases in restrictive cardiomyopathy CLINICAL ISSUES Presentation Most common signs/symptoms Dyspnea on exertion/shortness of breath at rest Jugular vein distention Pulmonary rales/cough 812

Diagnostic Imaging Cardiovascular Orthopnea Tachycardia Other signs/symptoms Nocturia/paroxysmal nocturnal dyspnea Fatigue Cerebral symptoms: Confusion, memory loss Pleural effusions Ascites, peripheral edema seen in RV failure Demographics Age Can affect any age Gender M=F Epidemiology Among leading causes of death in USA Natural History & Prognosis Prognosis worsens with increasing NYHA class Treatment Diuretics, ACE inhibitors, β-blockers, and inotropic agents are commonly used Treat underlying coronary disease DIAGNOSTIC CHECKLIST Consider Pulmonary venous redistribution and azygos vein diameter may not be evaluable on nonupright radiographs Image Interpretation Pearls RV or biventricular failure can be differentiated from LV failure by presence (RV failure) or absence (LV failure) of distended systemic veins (e.g., inferior vena cava, superior vena cava, azygos vein) on CXR, CT, or MR SELECTED REFERENCES 1. Braunwald E et al: Heart Disease: A Textbook of Cardiovascular Medicine. 6th ed. Philadelphia: W. B. Saunders. 509625, 2005 2. Ahmed A: American College of Cardiology/American Heart Association Chronic Heart Failure Evaluation and Management guidelines: relevance to the geriatric practice. J Am Geriatr Soc. 51(1):123-6, 2003 3. Goldman L et al: Cecil Textbook of Medicine. 21st ed. Philadelphia: W. B. Saunders. 207-26, 2000 P.9:13

Image Gallery

(Left) Four-chamber view MR cine (top) and LGE (bottom) images from a patient with ischemic cardiomyopathy show thinning and dilatation of the LV apex due to prior infarction, as demonstrated on the LGE MR image . (Right) Vertical long-axis (2-chamber) LGE MR image of a patient with ischemic cardiomyopathy demonstrates an anterior wall infarction noted by extensive subendocardial enhancement of the anterior wall and apex . The infarction is in the left anterior descending (LAD) territory. 813

Diagnostic Imaging Cardiovascular

(Left) Short-axis LGE images at the midventricular (left) and apical (right) levels show subendocardial enhancement of the anterior wall and anteroseptum , signifying prior LAD territory infarction. (Right) Short-axis LGE MR in a patient with dilated nonischemic cardiomyopathy demonstrates a linear stripe of hyperenhancement that is limited to the mid wall of the interventricular septum . This pattern is clearly different from an ischemic pattern, which would involve the subendocardium.

(Left) Short-axis LGE MR image in a patient with congestive heart failure and amyloidosis shows hyperenhancement affecting the endocardial half of the myocardium throughout the entire left ventricle . (Right) Short-axis LGE MR in a patient with new onset of heart failure due to viral myocarditis shows 2 regions of hyperenhancement: A linear mid-wall stripe in the interventricular septum and a large confluent region affecting the epicardial half of the LV lateral wall .

Heart Transplant Heart Transplant John P. Lichtenberger, III, MD Stephan Achenbach, MD Key Facts Terminology Most frequent form: Orthotopic cardiac allograft transplantation Operative technique: Biatrial anastomosis, bicaval anastomosis, or total transplantation Acute cellular rejection T-cell-mediated inflammatory response leading to myocardial edema and myocyte damage Occurs with decreasing frequency with increasing time interval since transplantation 814

Diagnostic Imaging Cardiovascular Usually detected by endomyocardial biopsy in an asymptomatic stage Coronary transplant vasculopathy Diffuse intimal thickening of coronary vessels Luminal narrowing, ischemia, and graft failure Imaging Assessment of left ventricular function Echocardiography, MR Assessment of cardiac allograft vasculopathy Ischemia imaging by stress echocardiography, myocardial perfusion imaging, and MR Invasive angiography + IVUS; coronary CTA Assessment of acute rejection Endomyocardial biopsy; gallium-67 scintigraphy Impaired diastolic function: Echocardiography, MR Imaging of edema by MR Top Differential Diagnoses Left ventricular dysfunction following heart transplantation Coronary arterial narrowing or occlusion following heart transplantation Clinical Issues Acute rejection occurs most frequently in 1st year Graft vasculopathy has increasing prevalence in following years, ˜ 50% after 10 years

(Left) Anteroposterior chest radiograph from a patient after heart transplant shows a retained portions of a cardiac pacing wire in the left brachiocephalic vein and sternotomy wires, which may be clues to the history of orthotopic heart transplant when that clinical information is unavailable. (Right) Lateral chest radiograph from a different patient status post heart transplantation shows retained cardiac pacing wire fragments and left ventricular epicardial pacing wires .

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(Left) Axial CECT from a patient status post median sternotomy shows suture material and indentations at the aortic and pulmonary arterial anastomoses present in all commonly performed orthotopic heart transplantations. (Right) Axial CECT from a patient status post orthotopic heart transplantation shows suture material at the right atrial wall , atrial waist due to anastomosis at the left atrium , and characteristic biatrial elongation. P.9:15

TERMINOLOGY Definitions Most frequent form: Orthotopic cardiac allograft transplantation Replacement of patient's heart with human donor's organ Other forms of transplantation Heterotopic cardiac allograft transplantation Infrequently performed Cardiac xenograft transplantation Not performed Common complications of cardiac transplantation Acute cellular rejection Cardiac allograft vasculopathy IMAGING General Features Most common procedure: Orthotopic cardiac allograft transplantation Biatrial anastomosis (a.k.a. Shumway technique): Findings of anastomosis of Right atrium Left atrium Aorta Pulmonary artery Bicaval anastomosis: Anastomosis of Vena cava superior Vena cava inferior Left atrium Aorta Pulmonary artery Total transplantation (a.k.a. Banner technique): Anastomosis of Vena cava superior Vena cava inferior Pulmonary veins Aorta Pulmonary artery Common complications of cardiac transplantation Cardiac allograft vasculopathy 816

Diagnostic Imaging Cardiovascular Coronary atherosclerosis May have been transplanted with the heart May develop in accelerated form after transplant Acute cellular rejection Infection Malignancies Imaging Recommendations Best imaging tool Echocardiography Used for assessing left and right ventricular function Cardiac MR Best modality to identify transplant rejection and left and right ventricular failure Invasive coronary angiography, intravascular ultrasound, and coronary CTA Used for identifying coronary atherosclerosis and cardiac allograft vasculopathy MR and gallium-67 scintigraphy May identify transplant rejection Endomyocardial biopsy Frequently performed for rejection monitoring Protocol advice Monitoring allograft systolic function important in suspected or known rejection Late gadolinium enhancement imaging and T2WI should be included in cardiovascular MR protocol Renal insufficiency is common in transplant patients Iodinated contrast and gadolinium should be used judiciously and with precautions Heart rate control may be challenging when performing coronary CTA Echocardiographic Findings Used to assess left ventricular systolic and diastolic functions Left ventricular diastolic dysfunction can be an early sign of acute cellular rejection Wall motion abnormalities in stress echocardiography can indicate presence of hemodynamically relevant coronary atherosclerosis or coronary allograft vasculopathy Angiographic Findings Invasive coronary angiography Often performed in serial fashion (annually) to monitor for coronary atherosclerosis and cardiac allograft vasculopathy Focal stenosis suggests coronary atherosclerosis Diffuse narrowing suggests cardiac allograft vasculopathy Both can be present without detectable narrowing in invasive coronary angiography Intracoronary ultrasound may be used to identify coronary artery affection not identified by angiography Concentric intimal thickening in case of transplant vasculopathy Eccentric lesions in case of transplant atherosclerosis Radiographic Findings Double right atrial contours (overlap of donor and recipient right atria in orthotopic transplant) Residual cardiac pacer wire fragments in thoracic veins CT Findings Atrial waist due to anastomosis of right and left donors and recipient atria Coronary calcium May occur in both cardiac allograft vasculopathy or coronary atherosclerosis Coronary CTA May be difficult to perform post transplantation when heart rate is high and difficult to control Diffuse plaque in cases of cardiac allograft vasculopathy Localized eccentric plaque and stenosis in case of coronary artery disease Not sufficiently evaluated for routine clinical evaluation MR Findings Best method to quantify left and right ventricular function Detection of transplant vasculopathy Several techniques have been suggested Stress myocardial perfusion MR P.9:16

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Diagnostic Imaging Cardiovascular Late gadolinium enhancement of coronary artery wall Not sufficiently evaluated Detection of acute rejection Abnormal T2 prolongation is strong predictor of rejection when clinically suspected Not sufficiently validated for clinical application DIFFERENTIAL DIAGNOSIS Left Ventricular Dysfunction Following Heart Transplantation Consequence of allograft rejection Consequence of ischemia Coronary atherosclerosis Cardiac allograft vasculopathy Consequence of recipient disease reaffecting the transplanted heart (infrequent) Amyloid Sarcoid Hemochromatosis Giant cell myocarditis Coronary Arterial Narrowing or Occlusion Following Heart Transplantation Often lack of symptoms due to denervation of transplanted heart Manifests as shortness of breath or reduced left ventricular function Consequence of transplant vasculopathy Coronary vessel wall thickening and luminal narrowing with diffuse pattern and concentric morphology Consequence of coronary artery disease Focal occurrence and eccentric morphology PATHOLOGY General Features Etiology Disease processes that require transplantation Nonischemic cardiomyopathy: 50% Ischemic cardiomyopathy: 40% Valvular heart disease: 3% Adult congenital heart disease: 2% CLINICAL ISSUES Demographics Epidemiology Over 5,000 cardiac transplants are performed worldwide annually 2,000-3,000 in USA each year Prevalence of cardiac allograft vasculopathy 8% within 1st year 32% within 1st 5 years 50% within 1st 10 years Natural History & Prognosis Endomyocardial biopsy may be used for surveillance or diagnosis of rejection 1-year survival of heart transplant recipients: 90% 5-year survival rate: ˜ 70% Graft half-life: ˜ 10 years Causes of death In 1st year after surgery Graft failure and infectious disease are leading causes of death Infectious disease accounts for almost 33% of deaths Acute rejection accounts for 12% of deaths Beyond 1st year Transplant vasculopathy Malignancies Especially, lymphoproliferative disorders and skin cancer Incidence of any malignancy is 35% by 10 years Treatment Retransplantation is required in 2% of cases Post-transplant immunosuppression often includes Calcineurin inhibitors (ciclosporin, tacrolimus, etc.) 818

Diagnostic Imaging Cardiovascular mTOR inhibitors (sirolimus, everolimus, etc.) Antimetabolites (mycophenolate, azathioprine) and steroids (prednisone) DIAGNOSTIC CHECKLIST Consider Orthotopic transplantation shows enlarged atria due to anastomosis of donor's heart with recipient's atria 2 atrial appendages may be present Impaired left ventricular function may be due to Rejection Ischemia Suboptimal donor heart Recipient disease (re)affecting transplanted heart Malignancies are frequent in patients with transplants SELECTED REFERENCES 1. Pollack A et al: Detection and imaging of cardiac allograft vasculopathy. JACC Cardiovasc Imaging. 6(5):613-23, 2013 2. Christie JD et al: The Registry of the International Society for Heart and Lung Transplantation: 29th adult lung and heart-lung transplant report-2012. J Heart Lung Transplant. 31(10):1073-86, 2012 3. Butler CR et al: Cardiovascular magnetic resonance in the diagnosis of acute heart transplant rejection: a review. J Cardiovasc Magn Reson. 11:7, 2009 4. Estep JD et al: The role of multimodality cardiac imaging in the transplanted heart. JACC Cardiovasc Imaging. 2(9):1126-40, 2009 5. Hunt SA et al: The changing face of heart transplantation. J Am Coll Cardiol. 52(8):587-98, 2008 6. Schmauss D et al: Cardiac allograft vasculopathy: recent developments. Circulation. 117(16):2131-41, 2008 7. Bogot NR et al: Cardiac CT of the transplanted heart: indications, technique, appearance, and complications. Radiographics. 27(5):1297-309, 2007 8. Hoffman FM: Outcomes and complications after heart transplantation: a review. J Cardiovasc Nurs. 20(5 Suppl):S3142, 2005 P.9:17

Image Gallery

(Left) Double oblique reformat from ECG-gated CTA in a patient status post orthotopic heart transplantation shows diffuse luminal narrowing of the right coronary artery secondary to a noncalcified plaque. CTA may be difficult to perform in transplant patients with high heart rates. (Right) Angiography of the right coronary artery in the same patient shows diffuse luminal narrowing and irregularity. Angiography may be used as a surveillance technique for coronary allograft vasculopathy.

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(Left) Angiography of the left anterior descending (LAD) artery shows diffuse luminal narrowing of the coronary arteries, consistent with cardiac allograft vasculopathy. Plaque in this disease tends to be concentric and diffuse. (Right) Angiography of the LAD shows focal narrowing consistent with coronary atherosclerosis. This disease may have been transplanted with the heart or developed in accelerated form after transplantation and is characterized by focal, eccentric plaque.

(Left) Four-chamber T2WI FS CMR shows diffuse hyperintensity of the right ventricular free wall , suspicious for mural edema and transplant rejection. Abnormal T2 prolongation is a strong predictor of rejection when clinically suspected. (Right) Coronal SSFP CMR shows a heterotopic heart transplant . The native pulmonary artery and left ventricle are enlarged. This transplant is rarely performed, used in patients with severe pulmonary arterial hypertension or a small donor heart.

Ventricular Assist Devices Ventricular Assist Devices John P. Lichtenberger, III, MD Key Facts Terminology Mechanical pump device used to augment cardiac output for failing ventricle Imaging Anatomy Implantable devices typically consist of Inflow cannula Implanted pump device Outflow cannula 820

Diagnostic Imaging Cardiovascular Percutaneous devices have no implanted component and are temporary by design Indicators of normal left ventricular assist device function include Neutral interventricular septum Aortic valve closed throughout cardiac cycle Anatomy-based Imaging Issues Field of view should include aortic arch and abdomen Use retrospectively ECG-gated CT with contrast Inflow and outflow cannulas may not be visible radiographically Orientation of inflow cannula in left ventricle is important; ideally no contact with ventricular walls MR is contraindicated Pathology-based Imaging Issues Aortic stenosis occurs in 88% of patients with left ventricular assist device Right heart failure occurs in 20-30% of cases Clinical Implications Bridge to cardiac transplant “Destination” therapy Bridge to myocardial recovery Post-Procedure Complications Infection Device failure Postoperative bleeding

(Left) Graphic depicts a HeartMate XVE left ventricular assist device (LVAD) with an inflow cannula inserting into the left ventricle and an outflow cannula inserting into the ascending aorta. Connection to an external power source is required for operation. (Right) Anteroposterior chest radiograph shows a HeartMate LVAD in place. Note that the outflow cannula is not radiopaque at its insertion in the ascending aorta, and the inflow cannula should project over the left ventricular apex.

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(Left) Graphic depicts a HeartMate II LVAD. The inflow cannula is in the left ventricular apex , and the outflow cannula inserts into the ascending aorta . The pump device is smaller in this model, although an external power source (not shown) is still required. (Right) Anteroposterior chest radiograph shows a HeartMate II LVAD. The outflow cannula is not radiopaque at its insertion into the ascending aorta. The inflow cannula is at the left apex . P.9:19

TERMINOLOGY Abbreviations Left ventricular assist device (LVAD) Right ventricular assist device (RVAD) Biventricular assist device (BiVAD) Percutaneous ventricular assist device (pVAD) Definitions Mechanical pump device used to augment cardiac output for failing ventricle LVAD goal Diverting oxygenated blood from left heart into aorta, bypassing left ventricular function RVAD goal Diverting blood from right ventricle to pulmonary artery, bypassing right ventricular function FDA approval of 1st LVAD as bridge to transplant was in 1994 IMAGING ANATOMY General Anatomic Considerations Device components are variable Implantable devices are typically composed of Inflow cannula Implanted pump device Outflow cannula Percutaneous devices have no implanted component and are temporary by design May access left atrium by transseptal puncture via femoral vein; blood is returned via femoral artery cannula (TandemHeart) May access left ventricle by crossing aortic valve via femoral artery (Impella) Cannula position Inflow cannula is typically at left ventricular apex without contacting a ventricular wall Outflow cannula may insert into ascending or descending aorta May be displaced from retrosternal position to protect cannula in case of repeat sternotomy Cannula may be insulated with protective material Coronary grafts may be connected to outflow cannula Indicators of normal LVAD function Neutral interventricular septum Aortic valve closed throughout cardiac cycle Minimal aortic regurgitation 822

Diagnostic Imaging Cardiovascular Significant reduction in mitral regurgitation from preop ANATOMY-BASED IMAGING ISSUES Imaging Protocols Retrospectively ECG-gated CT, with contrast if possible Field of view should include aortic arch and abdomen MR is contraindicated Imaging Pitfalls Inflow and outflow cannulas may not be visible radiographically Orientation of inflow cannula in left ventricle is important, ideally avoiding contact with ventricular walls Percutaneous device position should be reported Impella curled tip should be within left ventricle; outflow portion should be in ascending aorta TandemHeart tip should be within left atrium; outflow portion should be in femoral arteries PATHOLOGY-BASED IMAGING ISSUES Key Concepts Aortic stenosis occurs in 88% of patients with LVAD Aortic insufficiency worsens over time with LVAD use Right heart failure occurs in 20-30% of cases Increases morbidity and mortality from LVAD Hepatic congestion and bleeding Decreased left ventricular filling Myocardial disease or increased pulmonary vascular resistance CLINICAL IMPLICATIONS Clinical Importance More effective treatment for end-stage heart failure than medical therapy Indications Bridge to cardiac transplant Effective hemodynamic support Maintains or improves other organ function “Destination” therapy For permanent use in patients not eligible for transplant Bridge to myocardial recovery Typically pVAD Severe refractory cardiogenic shock Extensive heart surgery Contraindications Implantable devices cannot be used in some very short or very thin patients Best Procedure Approach Preperitoneal pocket is preferred placement site Improved control of bleeding Easier management of pocket infections Prevents development of intraabdominal adhesions Intraabdominal position is reserved for smaller patients Imaging Findings Radiography Can visualize radiopaque structures, typically the pump component Dacron conduits are not visible Percutaneous devices are typically placed via femoral vessels, although Impella may be placed via subclavian artery Echocardiography Intraoperative and perioperative assessment Evaluation of flow dynamics Septal deviation may indicate right heart failure Outflow cannula position is difficult to image Limited by metal artifact P.9:20

CT Can visualize conduits as well as more radiodense components 823

Diagnostic Imaging Cardiovascular Evaluates inflow and outflow cannula Tamponade indications Mass effect on right heart and coronary sinus Reflux of contrast into thoracic veins or inferior vena cava Dilation of inferior vena cava Thrombus may be within left ventricle adherent to cannula Aortic valve area is used to assess aortic stenosis Evaluates valvular disease, thickening of leaflets, valve area May calculate systolic and diastolic volumes for functional analysis Gas or fluid collections around the device may indicate infection EQUIPMENT Types Extracorporeal nonpulsatile Extracorporeal pulsatile Implantable pulsatile Total artificial heart Components Pump Surgically implanted in abdomen Inflow conduit Conducts blood from left ventricular apex to pump Outflow conduit Conducts blood from pump to ascending or descending aorta Internal valves Ensures unidirectional flow External power source Pneumatic Patient is confined to hospital Electrical Portable battery packs can let patients live at home Power leads pass through skin to pump External controller System function settings System status Devices 1st-generation pulsatile pumps simulate cardiac cycle HeartMate Implantable Novacor Implantable Thoratec Extracorporeal Biventricular 2nd-generation nonpulsatile continuous flow pumps Smaller and easier to implant Quieter DeBakey VAD Artificial hearts Significant complications limit use CardioWest AbioCor pVAD Impella TandemHeart POST-PROCEDURE Expected Outcome Typically a bridge to cardiac transplant or myocardial recovery Reverse remodeling while on LVAD has been described May reverse a number of adaptive cardiac changes at cellular/molecular level May restore basic cardiac function in some patients Complications Infection Typically bacterial or fungal 824

Diagnostic Imaging Cardiovascular Device failure Low flow rates Cannula obstruction Hypertrophic ventricular wall Right heart failure Tamponade, hypovolemia Inflow and outflow cannula thrombosis Tearing at cannula attachment site Postoperative bleeding Hemopericardium, mediastinal hemorrhage Focal accumulations of blood around inflow or outflow cannulas may be an expected postoperative finding Tamponade Cardiac complications Aortic stenosis or insufficiency Right heart failure Arrhythmia from cannula contact with ventricular wall Thromboembolic Pulmonary infarction Cerebral infarction Other end-organ infarction Pleural complications Pneumothorax Hemothorax: Presumptive diagnosis if sudden postoperative accumulation of large amount of pleural fluid Abdominal complications Hemoperitoneum Abscess Bowel obstruction SELECTED REFERENCES 1. Mellnick VM et al: Imaging of left ventricular device complications. J Thorac Imaging. 28(2):W35-41, 2013 2. Mishkin JD et al: Utilization of cardiac computed tomography angiography for the diagnosis of left ventricular assist device thrombosis. Circ Heart Fail. 5(2):e27-9, 2012 3. Bolen MA et al: Left ventricular assist device malposition interrogated by 4-D cine computed tomography. J Cardiovasc Comput Tomogr. 5(3):186-8, 2011 4. Kar B et al: The percutaneous ventricular assist device in severe refractory cardiogenic shock. J Am Coll Cardiol. 57(6):688-96, 2011 5. Carr CM et al: CT of left ventricular assist devices. Radiographics. 30(2):429-44, 2010 6. Estep JD et al: The role of echocardiography and other imaging modalities in patients with left ventricular assist devices. JACC Cardiovasc Imaging. 3(10):1049-64, 2010 P.9:21

Image Gallery

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(Left) Axial CECT shows a HeartMate II LVAD inflow cannula tip in the left ventricular chamber via the apex. The outflow cannula is often routed lateral to the sternum in anticipation of a subsequent sternotomy. (Right) Oblique coronal CT MIP shows a HeartMate II LVAD with its inflow cannula in the left ventricular apex . The continuous flow pump is in the upper abdomen, and the outflow cannula is retrosternal in this case.

(Left) Anteroposterior chest radiograph shows a right ventricular assist device with its inflow cannula in the right atrium and its outflow cannula in the right ventricular outflow tract . The pump device is external to the patient, placed via the femoral vein. (Right) Percutaneous LVAD (Impella) is placed via the right subclavian artery. The coiled tip has not yet reached the left ventricular apex. The inflow cannula should be in the left ventricle, and the outflow cannula in the ascending aorta.

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(Left) Anteroposterior chest radiograph shows a TandemHeart LVAD placed via the right femoral vein. The inflow cannula of the device accesses the left atrium via a transseptal puncture. (Right) Anteroposterior abdominal radiograph of the same patient shows the inflow cannula placed via the right femoral vein. The pump is external to the patient, and the outflow cannula is placed in the femoral artery for retrograde perfusion of the aorta and systemic circulation.

Left Ventricular Hypertrophy Left Ventricular Hypertrophy Sanjeev A. Francis, MD Key Facts Terminology Increase in left ventricular (LV) wall thickness &/or myocardial mass due to ↑ cardiac myocyte size Imaging Echocardiogram is often the initial imaging test for evaluation of LV morphology and function ↑ myocardial mass; ↑ wall thickness Assessment of LV wall thickness can be limited if images are of poor resolution (i.e., limited acoustic windows) Cardiac MR is useful if there are equivocal findings on echocardiography or to evaluate for specific etiologies, such as hypertrophic cardiomyopathy or infiltrative cardiomyopathy Pathology Primary causes (due to genetic factors) Hypertrophic cardiomyopathy Secondary causes Hypertension, aortic stenosis, obesity, athlete's heart Characterization of hypertrophy Concentric hypertrophy: Uniform increase in wall thickness Asymmetric hypertrophy Eccentric hypertrophy: Normal or reduced wall thickness with increased LV cavity size Clinical Issues Population studies estimate a prevalence of LV hypertrophy of 15-21% LV hypertrophy is an independent predictor of cardiac mortality regardless of underlying etiology Diagnostic Checklist Consider hypertrophic cardiomyopathy or infiltrative heart disease in patients without significant hypertension or valvular heart disease

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(Left) Short-axis MR cine image shows moderate concentric left ventricular hypertrophy in an elderly man with heart failure and aortic stenosis. (Right) Three-chamber view MR cine in the same patient shows a thickened aortic valve with restricted leaflet excursion and an associated dephasing artifact due to turbulent flow across the aortic valve . Late gadolinium enhancement images (not shown) did not reveal evidence of focal fibrosis or scar to suggest an infiltrative process such as amyloidosis.

(Left) Short-axis MR cine image in a 16-year-old athlete who had a borderline echocardiogram after an abnormal ECG shows mild upper septal hypertrophy with a maximal wall thickness of 14 mm . (Right) Short-axis late gadolinium enhancement image from the same patient shows no evidence of focal fibrosis or scar. The differential for these findings includes physiologic remodeling from exercise (athlete's heart) or mild hypertrophic cardiomyopathy. P.9:23

TERMINOLOGY Abbreviations Left ventricular hypertrophy (LVH) Definitions Increase in left ventricular (LV) wall thickness &/or myocardial mass due to increase in cardiac myocyte size IMAGING Echocardiographic Findings Echocardiogram Often the initial imaging test for evaluation of LV morphology and function LV mass can be estimated using M-mode, 2D, or 3D techniques Assessment of LV wall thickness can be difficult if limited acoustic windows 828

Diagnostic Imaging Cardiovascular MR Findings Increased myocardial mass Reference values for LV mass with cardiac MR Males: 146 ± 20 g (74 ± 9 g/m2) Females: 108 ± 18 g (63 ± 8 g/m2) Increased wall thickness Normal end-diastolic wall thickness = 0.7-1.1 cm Mild LVH: 1.2-1.4 cm Moderate LVH: 1.5-1.9 cm Severe LVH: ≥ 2 cm CT Findings Cardiac gated CTA Can demonstrate increased wall thickness and myocardial mass if end-diastolic images are obtained Imaging Recommendations Best imaging tool Echocardiography is often the most accessible and practical initial test Cardiac MR is useful if there are equivocal findings on echocardiography or to evaluate for specific etiologies such as hypertrophic cardiomyopathy or infiltrative cardiomyopathy Protocol advice Cardiac MR: Steady-state free precession (SSFP) or cine gradient-echo sequences DIFFERENTIAL DIAGNOSIS Infiltrative Cardiomyopathy Patterns of late gadolinium enhancement may help identify infiltrative process PATHOLOGY General Features Etiology Primary causes (due to genetic factors) Hypertrophic cardiomyopathy Secondary causes Hypertension: Most common cause of LVH Aortic stenosis Obesity Athlete's heart Staging, Grading, & Classification Characterization of hypertrophy Concentric hypertrophy: Uniform increase in wall thickness Asymmetric hypertrophy Associated with hypertrophic cardiomyopathy but can also be seen with hypertensive heart disease Eccentric hypertrophy: Normal or reduced wall thickness with increased LV cavity size Seen in patients with valvular regurgitation and dilated cardiomyopathy Microscopic Features Increase in myocyte size CLINICAL ISSUES Presentation Clinical profile LVH on ECG Hypertension Systolic BP > 140 mm Hg; diastolic BP > 90 mm Hg Demographics Epidemiology Population studies estimate a prevalence of LVH of 15-21% ˜ 30% of adults in United States have hypertension Natural History & Prognosis LVH is independent predictor of cardiac mortality regardless of underlying etiology Treatment Targeted to underlying cause DIAGNOSTIC CHECKLIST Consider 829

Diagnostic Imaging Cardiovascular Consider hypertrophic cardiomyopathy or infiltrative heart disease in patients without significant hypertension or valvular heart disease SELECTED REFERENCES 1. Armstrong AC et al: LV mass assessed by echocardiography and CMR, cardiovascular outcomes, and medical practice. JACC Cardiovasc Imaging. 5(8):837-48, 2012 2. Rudolph A et al: Noninvasive detection of fibrosis applying contrast-enhanced cardiac magnetic resonance in different forms of left ventricular hypertrophy relation to remodeling. J Am Coll Cardiol. 53(3):284-91, 2009 3. Maceira AM et al: Normalized left ventricular systolic and diastolic function by steady state free precession cardiovascular magnetic resonance. J Cardiovasc Magn Reson. 8(3):417-26, 2006 4. Otto CM: Cardiomyopathies, hypertensive and pulmonary heart disease. In Otto CM: Textbook of Clinical Echocardiography. 2nd ed. Philadelphia: W. B. Saunders. 183-203, 2000 5. Devereux RB et al: Left ventricular hypertrophy and hypertension. Clin Exp Hypertens. 15(6):1025-32, 1993 6. Levy D et al: Prognostic implications of echocardiographically determined left ventricular mass in the Framingham Heart Study. N Engl J Med. 322(22):1561-6, 1990

Right Ventricular Hypertrophy Right Ventricular Hypertrophy Sanjeev A. Francis, MD Key Facts Terminology Increased right ventricular (RV) wall thickness &/or myocardial mass Imaging Increased RV wall thickness (> 5 mm) Increased RV mass Echocardiography is often initial imaging test RV systolic pressure can be estimated by measuring peak velocity of tricuspid regurgitant jet by Doppler Cardiac MR is gold standard for quantitative assessment of RV size and function Late gadolinium enhancement at anterior and posterior RV insertion sites in cases of RV pressure overload Pulmonary artery dilatation if there is pulmonary hypertension Cardiac CT RV wall thickness, mass, and volumes can be measured if end-diastolic images are acquired Top Differential Diagnoses Infiltrative cardiomyopathy Cardiac sarcoidosis Pathology RV pressure overload Congenital heart disease Primary pulmonary hypertension Secondary pulmonary hypertension: Acquired heart disease, especially left ventricular dysfunction; valvular heart disease; chronic pulmonary embolism; chronic obstructive pulmonary disease; chronic interstitial lung disease Hypertrophic cardiomyopathy Athlete's heart

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(Left) Short-axis MR cine of 37-year-old man with D-transposition of the great arteries, who underwent a Mustard atrial switch procedure as an infant, shows significant right ventricular (RV) hypertrophy with a D-shaped septum or left ventricle during systole, consistent with RV pressure overload . The right ventricle is connected to the aorta and is therefore the systemic ventricle. (Right) Axial cardiac CT image from the same patient shows significant hypertrophy of the RV free wall .

(Left) RVOT MR cine image from a 34-year-old man with congenital pulmonic stenosis shows thickening of the pulmonic valve with associated dephasing artifact due to pulmonic stenosis . (Right) Short-axis late gadolinium enhancement (LGE) image from the same patient shows 2 foci of LGE involving the anterior and inferior septa at the RV insertion sites. This pattern of LGE can be seen with RV pressure overload. Due to progressive dyspnea, the patient underwent balloon valvuloplasty. P.9:25

TERMINOLOGY Abbreviations Right ventricular hypertrophy (RVH) Definitions Increased right ventricular (RV) wall thickness &/or myocardial mass IMAGING Radiographic Findings Radiography Diminished retrosternal clear space on lateral radiograph and elevation of cardiac apex Echocardiographic Findings 831

Diagnostic Imaging Cardiovascular Echocardiogram Increased RV wall thickness RV mass can be difficult to measure using conventional echocardiography RV mass may be more accurately measured using 3D techniques Evidence of RV pressure overload if there is concomitant pulmonary hypertension RV systolic pressure can be estimated by measuring peak velocity of tricuspid regurgitant jet by Doppler D-shaped septum during systole can be seen with RV pressure overload Right atrial pressure (P right atrium) can be estimated by size of inferior vena cava (IVC) Normal IVC: 1.5-2.5 cm, 5-15 mm Hg Dilated IVC: > 2.5 cm, 15-20 mm Hg Dilated, enlarged hepatic veins: > 20 mm Hg MR Findings Increased RV wall thickness (> 5 mm) Increased RV mass More inter- and intraobserver variability compared to measurements of left ventricle Normal values Male: 11.7 ± 2.0 g/m2 Female: 11.0 ± 1.7 g/m2 Late gadolinium enhancement at anterior and inferior RV insertion sites in cases of RV pressure overload Pulmonary artery dilatation if there is pulmonary hypertension CT Findings Cardiac gated CTA RV wall thickness, mass, and volumes can be measured if end-diastolic images are acquired Imaging Recommendations Best imaging tool Echocardiography is often initial imaging test Cardiac MR is gold standard for quantitative assessment of RV size and function Protocol advice Cardiac MR Steady-state free precession (SSFP) or cine gradient-echo imaging Late gadolinium enhancement may show patterns of fibrosis indicative of RV pressure overload or may suggest an alternative etiology DIFFERENTIAL DIAGNOSIS Infiltrative Cardiomyopathy Typically associated with increased left ventricular wall thickness May show diffuse or focal late gadolinium enhancement Cardiac Sarcoidosis May be associated with increase in left or right ventricular wall thickness May show various patterns of late gadolinium enhancement Mediastinal adenopathy may be present PATHOLOGY General Features Etiology RV pressure overload Congenital heart disease Tetralogy of Fallot Transposition of great vessels Primary pulmonary hypertension Secondary pulmonary hypertension: Acquired heart disease, especially left ventricular dysfunction; valvular heart disease; chronic pulmonary embolism; chronic obstructive pulmonary disease; chronic interstitial lung disease Hypertrophic cardiomyopathy Athlete's heart CLINICAL ISSUES Presentation Clinical profile Symptoms depend on underlying etiology and can include exertional dyspnea, chest pain, and lightheadedness 832

Diagnostic Imaging Cardiovascular RVH on ECG Right-axis deviation on ECG Treatment Depends on underlying etiology Pulmonary hypertension: Vasodilators Congenital heart disease: Surgical or percutaneous therapy depending on nature of anatomic defects, symptoms, & associated impact on RV size or function Left-sided heart disease: Medical &/or surgical therapy as indicated SELECTED REFERENCES 1. Blalock SE et al: Interstudy variability in cardiac magnetic resonance imaging measurements of ventricular volume, mass, and ejection fraction in repaired tetralogy of fallot: A prospective observational study. J Magn Reson Imaging. Epub ahead of print, 2013 2. Kawut SM et al: Sex and race differences in right ventricular structure and function: the multi-ethnic study of atherosclerosis-right ventricle study. Circulation. 123(22):2542-51, 2011 3. Lorenz CH: Right ventricular anatomy and function in health and disease. In Manning WJ et al: Cardiovascular Magnetic Resonance. Philadelphia: Churchill-Livingstone. 283-92, 2002

PVH/Pulmonary Edema (Cardiogenic) PVH/Pulmonary Edema (Cardiogenic) Carol C. Wu, MD Melissa L. Rosado-de-Christenson, MD, FACR Key Facts Terminology Pulmonary venous hypertension (PVH) = elevated left atrial and ventricular filling pressures → increased pulmonary venous pressure Cardiogenic pulmonary edema = PVH → elevated pulmonary capillary pressure → increased transudation of fluid into lung's interstitial and alveolar spaces Imaging Radiography Vascular indistinctness Fissural and bronchial wall thickening Kerley B lines Consolidation Cardiomegaly Pleural effusion CT Thickening of septa and fissures Bronchial wall thickening Centrilobular or patchy ground-glass opacities Consolidation Cardiomegaly Pleural effusions Increased attenuation of mediastinal fat Mediastinal lymph node enlargement Top Differential Diagnoses Interstitial edema: Lymphangitic carcinomatosis Alveolar edema: Pneumonia, hemorrhage Interstitial and alveolar edema: Alveolar proteinosis Clinical Issues Dyspnea; orthopnea; paroxysmal nocturnal dyspnea B-type natriuretic peptide (BNP); 90% accuracy Diagnostic Checklist Prior studies helpful in detection of early findings

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(Left) PA chest radiograph of a patient with mitral valve disease shows pulmonary venous hypertension manifesting with vascular redistribution. The upper lung zone vessels are larger than those in the lower lung. (Right) PA chest radiograph in chronic left ventricular failure shows pulmonary venous hypertension manifesting with enlargement of upper lobe pulmonary vessels , which are much larger than adjacent bronchi. Note that a dilated azygos vein indicates biventricular failure.

(Left) PA radiograph shows thickening of an interlobar fissure and many short subpleural Kerley B lines perpendicular to the pleural surface , consistent with interstitial edema. (Right) Coronal reformat CECT of a patient with interstitial edema demonstrates thick interlobular septa and thick interlobar fissures secondary to edema of the subpleural interstitium. Subpleural edema may precede septal thickening and peribronchial cuffing as a manifestation of interstitial edema. P.9:27

TERMINOLOGY Synonyms Hydrostatic pulmonary edema Definitions Pulmonary venous hypertension (PVH) = elevated left atrial and ventricular filling pressures → increased pulmonary venous pressure Cardiogenic pulmonary edema = PVH → elevated pulmonary capillary pressure → increased transudation of fluid into interstitial and alveolar spaces of lung IMAGING General Features 834

Diagnostic Imaging Cardiovascular Best diagnostic clue Pulmonary venous redistribution Kerley B lines (interstitial edema) Perihilar consolidation (alveolar edema) Pleural effusions Cardiomegaly Radiographic Findings Pulmonary venous hypertension Vascular redistribution or cephalization Size of upper lobe veins ≥ size of lower lobe veins Based on radiograph taken in upright position Can be seen in supine position without PVH Ratio of upper lung zone pulmonary arteries to bronchus diameter > ratio in lower lung zone Based on diameter of end-on pulmonary arteries and adjacent bronchus True also for supine radiograph but difficult to measure on portable radiograph Interstitial edema Perihilar haze or vascular indistinctness Earliest manifestation of interstitial edema Blurred or indistinct vessel wall margins Comparison with previous radiograph helpful Subpleural edema: Fluid in subpleural interstitium Thickening of interlobar fissures Lamellar density parallel to chest wall Can mimic pleural effusion at costophrenic angle Bronchial wall thickening (peribronchial cuffing): Fluid in peribronchial interstitium Increased thickness of airway walls Posterior wall of bronchus intermedius on lateral radiograph > 3 mm Septal thickening Kerley A lines Central linear opacities radiating from hila Length ≤ 4 cm Kerley B lines Thickened interlobular septa Basilar peripheral horizontal thin lines; perpendicular to pleura Length < 1 cm Alveolar edema Consolidation and ground-glass opacity Poorly marginated Usually bilateral Predilection for right lung if unilateral Preferential involvement of right upper lobe in mitral regurgitation “Bat's wing” pattern Central, perihilar opacity with sparing of periphery < 10% of cases Distribution affected by underlying lung disease Greater involvement of lower lung zone in patients with upper lung zone emphysema Distribution changes with gravity Increased opacity in dependent portion of lung if patient remains in same position for a few hours Associated findings Cardiomegaly Transverse cardiac diameter > 1/2 transverse thoracic diameter Characteristic of chronic cardiogenic edema Typically absent in acute edema and COPD Pleural effusion Often bilateral, larger on right Rarely unilateral on left Meniscus sign formed by interface of pleural fluid and adjacent aerated lung Blunt costophrenic angle 835

Diagnostic Imaging Cardiovascular Lateralization of apparent dome of diaphragm on frontal radiograph Fissural pseudotumor: Fluid within interlobar fissure Typical of pleural effusion in heart failure Widened vascular pedicle Marker of increased central venous pressure and circulating blood volume Useful when comparison studies are available Vascular pedicle width measurement = horizontal distance between right and left margins Right margin: Superior vena cava interface where it crosses right main stem bronchus Left margin: Lateral border of left subclavian artery as it arises from aorta Varies with body habitus, mediastinal fat Measures up to 58 mm in normal subjects Dilated azygos vein Seen end-on at right tracheobronchial angle > 1 cm on upright radiograph considered dilated Indicates systemic venous hypertension/right ventricular failure Temporal relationship of cardiogenic edema Unpredictable sequence of findings Interstitial edema may not follow PVH Alveolar edema may not follow interstitial edema Imaging findings may manifest before clinical signs Interstitial edema resolves in hours to days Radiographic improvement lags behind clinical course CT Findings Pulmonary venous hypertension Cardiomegaly with dilated left atrium Vascular redistribution Enlarged central pulmonary arteries with respect to adjacent bronchi Interstitial edema Smooth thickening of interlobular septa and interlobar fissures Bronchial wall thickening/cuffing Mild diffuse ground-glass attenuation P.9:28

Subpleural curvilinear band-like opacity (subpleural edema) Alveolar edema Ground-glass opacity or consolidation Centrilobular ground-glass nodules Distribution Diffuse or patchy Bilateral perihilar; “bat's wing” pattern Findings of interstitial edema can also be seen in setting of alveolar edema Associated findings Pleural effusions Mediastinal lymph node enlargement Increased attenuation of mediastinal fat Imaging Recommendations Best imaging tool Chest radiography; prior studies are helpful in detection of early findings DIFFERENTIAL DIAGNOSIS Interstitial Edema Lymphangitic carcinomatosis Usually known malignancy Nodular or irregular interlobular septal thickening Patchy distribution ± lymphadenopathy and pleural effusion Alveolar Edema Permeability edema Gravity-dependent density gradient with dense consolidation in posterobasal segments 836

Diagnostic Imaging Cardiovascular Absence of cardiomegaly or widened vascular pedicle Septal lines and bronchial wall thickening are less common than in cardiogenic edema Pneumonia Signs and symptoms of infection Focal or multifocal consolidation and ground-glass opacities Usually evolve less rapidly than in pulmonary edema Parapneumonic pleural effusion Pulmonary hemorrhage Consolidation and ground-glass opacities Centrilobular nodules Interstitial and Alveolar Edema Pulmonary alveolar proteinosis “Crazy-paving” pattern on CT No cardiomegaly or pleural effusion PATHOLOGY General Features Etiology Left ventricular dysfunction Uncontrolled hypertension Arrhythmias Myocardial infarction or ischemic cardiomyopathy Dilated cardiomyopathy Fluid overload Valvular disease Mitral regurgitation or stenosis Aortic regurgitation or stenosis Microscopic Features Widening of peribronchovascular interstitial space and interlobular septa Lymphatic distention Increased alveolar wall thickness Fluid-filled alveoli CLINICAL ISSUES Presentation Most common signs/symptoms Dyspnea; orthopnea; paroxysmal nocturnal dyspnea Diaphoresis Tachypnea; tachycardia Jugular vein distension Basilar rales Other signs/symptoms Pink, frothy sputum Cough Clinical profile B-type natriuretic peptide (BNP) Serum level used for diagnosing congestive heart failure Produced as response to ventricular stretch/strain 80-90% accuracy; 96% negative predictive value Pulmonary capillary wedge pressure (PCWP) Evolving role for use of pulmonary artery catheterization Rate of adverse complications: 5-10% Recent randomized studies did not show mortality benefits > 18 mm Hg in hydrostatic edema Natural History & Prognosis Acute or insidious course Prognosis depends on severity and reversibility of underlying hemodynamic dysfunction Treatment Preload and afterload reduction Intraaortic balloon pump Ultrafiltration 837

Diagnostic Imaging Cardiovascular DIAGNOSTIC CHECKLIST Consider Appearance of cardiogenic edema is affected by anatomic abnormalities, especially emphysema SELECTED REFERENCES 1. Morrissey RP et al: Chronic heart failure: current evidence, challenges to therapy, and future directions. Am J Cardiovasc Drugs. 11(3):153-71, 2011 2. Myrianthefs P et al: Rare roentgenologic manifestations of pulmonary edema. Curr Opin Crit Care. 17(5):449-53, 2011 3. Wang CS et al: Does this dyspneic patient in the emergency department have congestive heart failure? JAMA. 294(15):1944-56, 2005 4. Ware LB et al: Clinical practice. Acute pulmonary edema. N Engl J Med. 353(26):2788-96, 2005 5. Gehlbach BK et al: The pulmonary manifestations of left heart failure. Chest. 125(2):669-82, 2004 6. Woolley K et al: Pulmonary parenchymal manifestations of mitral valve disease. Radiographics. 19(4):965-72, 1999 P.9:29

Image Gallery

(Left) PA chest radiograph of a patient with interstitial edema demonstrates profuse reticular opacities and peribronchial cuffing, best appreciated around bronchi seen end-on . (Right) Composite image shows a normal right lower lobe on CT (left) compared to CT findings of interstitial edema (right) manifesting with bronchial wall thickening , dilated pulmonary artery compared to adjacent bronchiole, and small right pleural effusion .

(Left) Axial CECT of a patient with interstitial edema shows smooth interlobular septal thickening. The interlobular septa appear as linear opacities that form polygonal arcades . (Right) Coned-down AP chest radiograph of a 838

Diagnostic Imaging Cardiovascular patient with interstitial pulmonary edema shows several horizontal peripheral short lines consistent with Kerley B lines , as well as longer oblique radial lines that represent Kerley A lines .

(Left) PA radiograph of a patient with emphysema who developed interstitial edema shows indistinct vascular margins and reticular lines predominantly in the lower lung zones, areas less affected by emphysema. (Right) PA radiograph of the same patient post treatment shows decrease in bilateral reticular lines and size of cardiac silhouette. Comparison films are helpful in evaluation of emphysema patients who often have atypical appearance and distribution of edema. P.9:30

(Left) Coned-down PA chest radiograph shows the method used to measure the vascular pedicle, which is the horizontal distance between the superior vena cava interface as it crosses the right main stem bronchus and the origin of the left subclavian artery. (Right) Composite image shows frontal radiographs of a patient with interstitial edema before (left) and after (right) treatment with resultant decreasing width of the vascular pedicle. A normal vascular pedicle may measure up to 58 mm.

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(Left) Axial CECT of a patient with interstitial edema shows increased attenuation of mediastinal fat, prominence of mediastinal lymph node , and small bilateral pleural effusions. Enlarged mediastinal lymph nodes are commonly seen in the setting of pulmonary edema. (Right) Axial CECT of a patient with mild alveolar edema demonstrates mild diffuse ground-glass opacities, which are more prominent in the dependent aspect of the lungs, and subtle groundglass centrilobular nodules .

(Left) AP chest radiograph shows asymmetric alveolar edema manifesting as bilateral perihilar haze and consolidation, most pronounced on the right. Note peribronchial cuffing , fissural pleural thickening (subpleural edema), and bilateral pleural effusions. (Right) Frontal chest radiograph of a patient with interstitial and alveolar edema shows cardiomegaly, bilateral pleural effusions, profuse fine reticular opacities, and asymmetric perihilar haze and consolidations. P.9:31

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(Left) Coronal CECT of a patient with alveolar edema shows patchy confluent, lobular, and acinar ground-glass opacities without interlobular septal thickening. (Right) Axial CECT of a patient with interstitial and alveolar edema shows septal thickening, patchy areas of ground-glass opacity, and small bilateral pleural effusions.

(Left) AP radiograph of a patient with acute mitral insufficiency shows asymmetric alveolar edema preferentially affecting the right upper lobe due to the direction of regurgitant blood flow across an incompetent mitral valve. Note cardiomegaly and left atrial appendage enlargement . (Right) Axial CECT shows interstitial and alveolar edema. Note abnormal upper lobe bronchoarterial ratios , bronchial wall thickening , and asymmetric alveolar edema .

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(Left) AP radiograph of a patient with “bat's wing” pulmonary edema demonstrates a bilateral perihilar consolidation with sparing of the lung periphery. Also note bilateral pleural effusions. (Right) Axial NECT of a patient with “bat's wing” pulmonary edema shows central perihilar consolidations with air bronchograms and sparing of the lung periphery. “Bat's wing” edema occurs in < 10% of patients with pulmonary edema.

Cor Pulmonale Key Facts Terminology Hypertrophy or dilatation &/or impaired function of right ventricle (RV) as a result of pulmonary hypertension Associated with diseases of pulmonary parenchyma or vasculature in absence of left ventricular (LV) dysfunction Imaging Chest radiography Central pulmonary artery (PA) enlargement Right heart enlargement CT Dilated central PA; main PA > 29 mm RV wall thickening RV dilatation; RV diameter to LV diameter ratio > 1 Flattening or leftward bowing of interventricular septum Findings associated with underlying pulmonary parenchymal diseases or pulmonary emboli MR Allows calculation of end-systolic and end-diastolic RV volumes and ejection fraction Paradoxical bowing of interventricular septum toward LV during systole RV hypertrophy, dilatation Tricuspid regurgitation Top Differential Diagnoses Right heart failure related to left heart failure or congenital heart disease Pathology Etiology COPD is most common cause in North America Interstitial lung disease Pulmonary embolism

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(Left) PA radiograph of a patient with sarcoidosis and cor pulmonale shows bilateral hilar enlargement , dilatation of the right atrium, and subtle bilateral peribronchovascular opacities . (Right) Axial CECT shows dilatation of main pulmonary trunk consistent with pulmonary hypertension. Fluid is noted in the anterior pericardial recess ,a common finding in cor pulmonale. Bilateral hilar lymphadenopathy and perilymphatic nodularity are related to sarcoidosis.

(Left) Axial CECT of the same patient shows dilatation of the right atrium and right ventricle with right ventricular diameter greater than left ventricular diameter. Note also straightening of the interventricular septum . These findings are consistent with cor pulmonale. (Right) Axial CECT shows reflux of the intravenous contrast material into the hepatic veins due to tricuspid regurgitation. There is also hepatomegaly due to passive congestion. P.9:33

TERMINOLOGY Definitions Hypertrophy or dilatation &/or impaired function of right ventricle (RV) as a result of pulmonary hypertension associated with diseases of pulmonary parenchyma or vasculature in absence of left ventricular (LV) dysfunction IMAGING Radiographic Findings Pulmonary hypertension Central pulmonary artery (PA) enlargement Pruning of distal PA branches Right heart enlargement 843

Diagnostic Imaging Cardiovascular Decreased retrosternal clear space on lateral view CT Findings Underlying pulmonary disease Emphysema Bronchial wall thickening related to bronchitis Reticulations, traction bronchiectasis, volume loss related to fibrotic interstitial lung disease Upper lobe-predominant perilymphatic nodules, fibrosis in sarcoidosis Upper lobe-predominant cysts and nodules in Langerhans cell histiocytosis Pulmonary artery Dilated central PA; main PA > 29 mm Pruning of peripheral PA Filling defects if pulmonary embolism is underlying cause Cardiac findings RV wall thickening RV dilatation; RV diameter to LV diameter ratio > 1 Flattening or leftward bowing of interventricular septum Dilated RA, superior vena cava, inferior vena cava Fluid within anterior pericardial recess Reflux of contrast into inferior vena cava or hepatic vein MR Findings MR cine Allows calculation of end-systolic and end-diastolic RV volumes and ejection fraction Paradoxical bowing of interventricular septum toward LV during systole Delayed enhancement Abnormal late gadolinium enhancement at RV insertion points ± interventricular septum RV hypertrophy Increased diastolic RV wall thickness RV assumes spherical shape and dilates, resulting in greater diameter than LV Tricuspid regurgitation Right atrial (RA) enlargement Echocardiographic Findings Paradoxical bulging of interventricular septum toward LV during systole RV and RA dilatation Tricuspid regurgitation Angiographic Findings Right heart catheterization Diagnostic gold standard Allows measurement of hemodynamic parameters Imaging Recommendations Best imaging tool Echocardiography is good screening modality for establishing diagnosis MR helpful for serial evaluation of RV structural and functional status DIFFERENTIAL DIAGNOSIS Right Heart Failure Other causes of right heart failure related to congenital heart diseases or left heart failure PATHOLOGY General Features Etiology Chronic obstructive pulmonary disease (COPD) is most common cause in North America Up to 30% of COPD patients are affected Interstitial lung disease Pulmonary arterial hypertension Idiopathic Connective tissue disease (i.e., scleroderma) related Obstructive sleep apnea Pulmonary embolism CLINICAL ISSUES Presentation Most common signs/symptoms 844

Diagnostic Imaging Cardiovascular Dyspnea on exertion Fatigue Other signs/symptoms Syncope Angina Anorexia, right quadrant discomfort Related to passive congestion of bowel and liver Natural History & Prognosis Patients with disease (e.g., COPD) complicated by cor pulmonale have worse prognosis than those with disease not complicated by cor pulmonale Usually chronic but can be acute Acute pulmonary emboli Acute exacerbation of chronic disease Treatment Supplemental oxygen Treat underlying cause of pulmonary hypertension Diuresis Intravenous inotropic agents, such as dobutamine or milrinone SELECTED REFERENCES 1. Okajima Y et al: Assessment of pulmonary hypertension what CT and MRI can provide. Acad Radiol. 18(4):437-53, 2011

Section 10 - Electrophysiology Imaging Before and After Electrophysiology Procedures > Table of Contents > Section 10 - Electrophysiology > Imaging Before and After Electrophysiology Procedures Imaging Before and After Electrophysiology Procedures Jonathan Hero Chung, MD Introduction Electrophysiology has been the fastest growing field of cardiology over the past few years. Imaging as a pre- or intraprocedural planning tool has become essential for electrophysiologists to minimize the risks of their invasive and technically difficult procedures. Furthermore, postprocedural imaging is imperative to detect acute and chronic complications. Atrial Fibrillation/Flutter Ablation Preprocedural planning and postprocedural follow-up are mandatory at most centers before and after catheter ablation for atrial fibrillation/flutter (AF). Transthoracic echocardiography is a first-line means to image the heart given that it is relatively inexpensive, available, and trusted. General cardiac anatomy, function, and gross congenital defects can be assessed by echocardiography without the use of ionizing radiation. However, this modality is limited by variability in user skill and acoustic windows in individual patients. Though transesophageal echocardiography may increase sensitivity for other cardiac findings, of which atrial appendage thrombus is the most important given the potentially devastating effect of acute dislodgement of the thrombus into the systemic arterial system, it is more expensive and obviously more invasive than its transthoracic counterpart. At many centers, cross-section imaging in the form of CT or MR is frequently used in preprocedural planning and postprocedural follow-up of AF catheter ablation. Anatomic and functional information can be obtained using CT or MR. Left atrial appendage visualization can be performed reliably using either CT or MR, allowing exclusion of appendage thrombus and minimizing risk of appendage perforation during catheter manipulation. These modalities are not as user dependent as echocardiography, especially in the setting of a strict imaging protocol tailored for assessment of the pulmonary veins and cardiac anatomy. Furthermore, extracardiac anatomy is well demonstrated using these modalities; in particular, location of the esophagus relative to the pulmonary vein ostia has the potential to minimize iatrogenic esophageal injury, fistula formation, and stenosis. Postprocedural complications such as pulmonary vein stenosis can be well assessed using either CT or MR, though infarct detection would be most reliably detected with MR due to its high contrast resolution. The main drawbacks of MR and CT are relative cost compared to transthoracic echocardiography and radiation dose from CT, as well as need for contrast material. Furthermore, subjects with implantable cardioverter defibrillators or pacemakers usually cannot be imaged using MR. However, there has been a release of new pacemakers that are MR-compatible. 845

Diagnostic Imaging Cardiovascular Cardiac Resynchronization Therapy/Implantable Cardioverter Defibrillator In cardiac resynchronization therapy (CRT), a lead is placed into a coronary vein to pace the left ventricle in the setting of dyssynchrony and advanced heart failure. Though coronary venography at the time of procedure is usually performed for anatomic mapping, this imaging technique is limited by its inherent 2D technique. Preprocedural planning using 3D noninvasive imaging of the coronary veins with MR or CT allows for a more accurate understanding of the venous anatomy during the procedure, which could lead to reduced fluoroscopy time and patient radiation exposure. Also, both MR and CT can provide functional information. The most delayed portion of the left ventricular myocardium can be targeted for therapy. Furthermore, growing evidence suggests that late gadolinium hyperenhancement imaging in cardiac MR may predict which patients respond favorably to CRT; patients with a larger degree of ventricular scar or with the lead in an area of scar on late gadolinium enhancement (LGE) imaging may have a less favorable response to CRT. In the setting of implantable cardioverter defibrillators (ICDs), CT and MR are as invaluable in preprocedural planning as in other invasive cardiac interventions. Post-gadolinium delayed hyperenhancement imaging in MR has the potential to help identify patients who are at risk for unstable cardiac arrhythmias and, therefore, require placement of an ICD. Ventricular Arrhythmia Ablation In the setting of ablation for ventricular tachycardia, preprocedural anatomic assessment is important and can be performed using echocardiography, MR, &/or CT. As in AF, exclusion of cardiac thrombus is important to avoid embolic phenomenon. MR is also helpful in identifying scar areas using LGE imaging. An area of scar likely contains the focus or substrate for the arrhythmia. The electrophysiologist can thereby focus on this portion of the myocardial anatomy when deciding on a site to ablate. Selected References 1. Haeusler KG et al: Left atrial catheter ablation and ischemic stroke. Stroke. 43(1):265-70, 2012 2. Heydari B et al: Imaging for planning of cardiac resynchronization therapy. JACC Cardiovasc Imaging. 5(1):93-110, 2012 3. Thai WE et al: Preprocedural imaging for patients with atrial fibrillation and heart failure. Curr Cardiol Rep. 14(5):584-92, 2012 4. van der Hoeven BL et al: Multimodality imaging in interventional cardiology. Nat Rev Cardiol. 9(6):333-46, 2012 5. Wang H et al: Real time three-dimensional echocardiography in assessment of left ventricular dyssynchrony and cardiac resynchronization therapy. Echocardiography. 29(2):192-9, 2012 6. Yamada T et al: Optimal ablation strategies for different types of ventricular tachycardias. Nat Rev Cardiol. 9(9):51225, 2012 7. Chiribiri A et al: Coronary imaging with cardiovascular magnetic resonance: current state of the art. Prog Cardiovasc Dis. 54(3):240-52, 2011 8. Daccarett M et al: MRI of the left atrium: predicting clinical outcomes in patients with atrial fibrillation. Expert Rev Cardiovasc Ther. 9(1):105-11, 2011 9. Dagres N et al: Prevention of atrial-esophageal fistula after catheter ablation of atrial fibrillation. Curr Opin Cardiol. 26(1):1-5, 2011 10. Dewire J et al: State-of-the-art and emerging technologies for atrial fibrillation ablation. Nat Rev Cardiol. 7(3):12938, 2010 11. Hasan R et al: Imaging modalities in cardiac electrophysiology. Future Cardiol. 6(1):113-27, 2010 12. Rajiah P et al: Computed tomography of pulmonary venous variants and anomalies. J Cardiovasc Comput Tomogr. 4(3):155-63, 2010 13. Robinson MR et al: Use of imaging techniques to guide catheter ablation procedures. Curr Cardiol Rep. 12(5):37481, 2010 P.10:3

Image Gallery

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(Left) Axial image from a cardiac CT shows narrowing at the ostium of the left inferior pulmonary vein , which developed as a complication of radiofrequency ablation of the pulmonary ostia. (Right) Axial CT from the same patient shows left superior pulmonary vein obliteration and left upper lobe infarction and hemorrhage from a pulmonary venous obstruction. The left lower pulmonary vein was stented, and the left upper lobe consolidation eventually resolved.

(Left) Axial image from cardiac CT of pulmonary veins shows a thrombus in the tip of the left atrial appendage in a patient with atrial fibrillation. (Right) Long-axis image from cardiac CT of pulmonary veins again demonstrates a thrombus in the tip of the left atrial appendage. Note that detection of a left atrial thrombus before radiofrequency ablation for atrial fibrillation is imperative to avoid distal systemic embolization of the thrombus.

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(Left) White blood cine image from cardiac MR during end-diastole shows dilation of the left ventricle. Thinning of the inferior and lateral walls of the left ventricle is also present. (Right) Delayed post-contrast short-axis image shows a large degree of delayed hyperenhancement involving the left ventricular myocardium . Given the large degree of scarring, the patient would be at risk for a poor response to cardiac resynchronization therapy.

Pulmonary Vein Mapping Key Facts Terminology Pulmonary veins (PVs) drain oxygenated blood from lungs into left atrium Electrical foci inside PVs may trigger atrial fibrillation, a common arrhythmia Catheter-based PV isolation is widespread treatment for atrial fibrillation and benefits from preprocedure PV imaging to guide ablation procedures Normal PV anatomy: 2 left and 2 right PVs drain into left atrium Anomalies of PV return PVs may drain into structures other than left atrium (most frequently right atrium or superior vena cava) Scimitar syndrome: PV return from right lung to right atrium Variants of PV return Any variant in which all PVs drain to left atrium, but there are < or > 2 right and 2 left PV ostia Imaging Transesophageal echocardiography can visualize PVs, but complete visualization of anatomy is difficult CTA and MRA are equally effective in defining PV anatomy prior to ablation; choice depends on local expertise and patient preference Clinical Issues PV ostia are often tapered; diagnosis of PV stenosis requires comparison of pre- and post-ablation images Variants of PV anatomy are present in 25-40% of patients undergoing PV ablation CT and MR images of PV anatomy are often fused with electroanatomical mapping systems to facilitate catheter guidance during atrial fibrillation ablation PV stenosis can occur following pulmonary vein ablation but has become infrequent with modern ablation techniques

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(Left) 3D reconstruction of normal pulmonary vein anatomy by contrast-enhanced multidetector-row CT, viewed from a posterior aspect, shows that the right upper , right lower , left upper , and left lower pulmonary veins enter the left atrium separately. The left atrial appendage is seen as well. (Right) Magnetic resonance angiography shows the left upper and left lower pulmonary veins, demonstrating that pulmonary veins can also be visualized on 2D imaging.

(Left) Pulmonary veins are seen during a kryoballoon ablation procedure. The left upper pulmonary vein ostium is blocked by a balloon, and contrast is injected to ensure complete blockage. (Right) Fusion of 3D anatomic imaging (in this case CTA) and electrophysiologic mapping shows the location of high-frequency energy applied to the left atrial wall (red dots). Several commercially available systems can be used for image fusion using DICOM data sets for anatomic reference and superimposing current catheter position. P.10:5

TERMINOLOGY Definitions Pulmonary veins drain oxygenated blood from lungs into left atrium Electrical foci inside pulmonary veins may trigger atrial fibrillation, a common arrhythmia Catheter-based pulmonary vein isolation is a widespread treatment for atrial fibrillation Pulmonary vein anatomy is important to guide ablation procedures Normal pulmonary vein anatomy: 2 left and 2 right pulmonary veins drain into left atrium Variants of pulmonary vein anatomy are common and include supernumerary veins draining into left atrium or single ostia for left or right pulmonary veins

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Diagnostic Imaging Cardiovascular Anomalies of pulmonary veins are defined as any pattern where pulmonary veins drain into structures other than left atrium (most frequently inferior vena cava [IVC], right atrium, or superior vena cava) Scimitar syndrome is infrequent pulmonary vein anomaly where pulmonary veins from right middle and lower lobe drain into IVC or right atrium IMAGING General Features In normal pulmonary vein anatomy (75-80% of individuals), 2 right and 2 left pulmonary veins have separate ostia into posterior wall of left atrium Right superior pulmonary vein is usually largest Most frequent variants are presence of a middle right pulmonary vein and a common left pulmonary vein trunk Most frequent anomaly is drainage of right superior pulmonary vein into superior vena cava, often associated with atrial septal defect Pulmonary vein stenosis may occur after ablation; however, pulmonary vein ostia often show tapering even before ablation Comparison of pre- and post-ablation images is mandatory to diagnose pulmonary vein stenosis Echocardiographic Findings In transesophageal echocardiography, ostia of pulmonary veins can be identified by skilled operators, but complete visualization of anatomy is difficult Angiographic Findings Invasive angiography Pulmonary veins can be visualized by invasive angiography after transseptal passage and balloon occlusion Performed during ablation process to verify balloon position (cryoablation) or catheter tip position (highfrequency current ablation) CT Findings CTA Identifies pulmonary vein anatomy with high resolution 3D reconstructions are helpful for interpretation Reformatted images allow measurement of pulmonary vein diameters CT images may be fused with electroanatomic imaging systems (e.g., CARTO for catheter guidance during ablation) MR Findings MRA Pulmonary vein anatomy is readily identified Reformatted images allow measurement of pulmonary vein diameters Imaging Recommendations Best imaging tool CTA and MRA are equally effective to define pulmonary vein anatomy prior to ablation Choice will depend on local expertise and patient preference CLINICAL ISSUES Presentation Variants of pulmonary vein anatomy are present in 25-40% of patients undergoing pulmonary vein ablation Pulmonary vein stenosis can occur following pulmonary vein ablation but has become infrequent with modern ablation techniques Left atrial appendage thrombus may be detectable on CT angiography images obtained for pulmonary vein ablation and constitutes a contraindication for the ablation procedure Be aware of false-positive findings of left atrial appendage thrombus due to delayed filling with contrast agent Data regarding relationship of ablation success and variants of pulmonary vein anatomy are inconsistent DIAGNOSTIC CHECKLIST Image Interpretation Pearls Pulmonary veins ostia are often tapered; therefore, diagnosis of pulmonary vein stenosis requires comparison of pre- and post-ablation images SELECTED REFERENCES 1. den Uijl DW et al: Effect of pulmonary vein anatomy and left atrial dimensions on outcome of circumferential radiofrequency catheter ablation for atrial fibrillation. Am J Cardiol. 107(2):243-9, 2011 2. Rajiah P et al: Computed tomography of pulmonary venous variants and anomalies. J Cardiovasc Comput Tomogr. 4(3):155-63, 2010

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Diagnostic Imaging Cardiovascular 3. Kaseno K et al: Prevalence and characterization of pulmonary vein variants in patients with atrial fibrillation determined using 3-dimensional computed tomography. Am J Cardiol. 101(11):1638-42, 2008. Erratum in: Am J Cardiol. 102(4):508, 2008 4. Lacomis JM et al: CT of the pulmonary veins. J Thorac Imaging. 22(1):63-76, 2007 5. Marom EM et al: Variations in pulmonary venous drainage to the left atrium: implications for radiofrequency ablation. Radiology. 230(3):824-9, 2004 6. Lacomis JM et al: Multi-detector row CT of the left atrium and pulmonary veins before radio-frequency catheter ablation for atrial fibrillation. Radiographics. 23 Spec No:S35-48; discussion S48-50, 2003 P.10:6

Image Gallery

(Left) Contrast-enhanced CT shows normal pulmonary vein anatomy. A multiplanar reconstruction in axial orientation shows the left upper pulmonary vein and right upper pulmonary vein . Note the left atrium and small cross section of the left atrial appendage. (Right) Multiplanar reconstruction, again in axial orientation but several centimeters caudal to the previous image, shows the left atrium and the left lower and right lower pulmonary veins.

(Left) Contrast-enhanced CT demonstrates the anatomy of all 4 pulmonary veins. Here, a multiplanar reconstruction (8 mm maximum-intensity projection thickness) shows the ostia of all 4 pulmonary arteries . (Right) 3D reconstruction of the left atrium and pulmonary veins shows the heart from a posterior view. The descending aorta and the spine have been removed.

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(Left) Maximum-intensity projection magnetic resonance angiography shows normal anatomy of the 4 pulmonary veins with separate ostia into the left atrium . Slight tapering of the lower left pulmonary artery is frequently seen even in healthy individuals. (Right) This 3D reconstruction of normal pulmonary vein anatomy is based on magnetic resonance angiography. P.10:7

(Left) Angiography shows the right upper pulmonary vein during a kryoballoon ablation procedure. The ostium of the right upper pulmonary vein is blocked by a balloon, and contrast is injected. (Right) Transesophageal echocardiography demonstrates the ostium of the left upper pulmonary vein , left atrial appendage , left atrium , and aorta

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(Left) Contrast-enhanced CT reconstructed to yield a 3D image shows a common ostium of the left superior and inferior pulmonary veins. The right-sided pulmonary veins demonstrate normal anatomy. (Right) Contrast-enhanced CT after 3D reconstruction shows an accessory pulmonary vein close to the ostium of the right upper pulmonary vein.

(Left) A right-sided middle pulmonary vein is another frequent variant of pulmonary vein anatomy. (Right) The ostium of the pulmonary veins is often tapered. Of special note, the left lower pulmonary vein frequently displays a substantially tapered ostium into the left atrium , which may partly be caused by the descending aorta being in immediate proximity. Note the position of the esophagus , which may be injured during left atrial electrophysiologic ablation procedures.

Pulmonary Vein Stenosis Key Facts Terminology Narrowed pulmonary vein after radiofrequency (RF) catheter ablation for atrial fibrillation Congenital stenosis of pulmonary vein in isolation or associated with congenital heart disease Imaging Any treated pulmonary vein is susceptible to stenosis Left inferior pulmonary vein ostia is most commonly affected ± pulmonary signs of venous hypertension in affected lung Interlobular septal thickening and ground-glass opacity Top Differential Diagnoses Pulmonary vein thrombosis 853

Diagnostic Imaging Cardiovascular Pulmonary vein varix Pathology Congenital stenosis is often associated with other congenital heart disease Stenosis may also follow repair of anomalous pulmonary venous return Consider lung cancer or metastasis in the setting of adjacent soft tissue mass Clinical Issues Frequently asymptomatic if single vein is involved Incidence from 3-42% depending on RF technique, imaging technique, definition of stenosis Symptomatic patients or asymptomatic patients with severe stenosis can be treated with balloon angioplasty and stent deployment Rationale for treating asymptomatic patient: Unknown risk of pulmonary hypertension, risk of progression to complete occlusion

(Left) Graphic shows the typical appearance of ostial left inferior pulmonary vein stenosis following radiofrequency ablation. (Right) Coronal oblique cardiac CT shows discrete narrowing of the left inferior pulmonary vein, as well as abnormal soft tissue in the expected region of the left superior pulmonary vein. The abnormal soft tissue represents the thrombosed superior pulmonary vein following radiofrequency ablation.

(Left) Posteriorly directed oblique MRA in a patient who underwent radiofrequency isolation of the pulmonary veins shows a focal web-like narrowing of the left superior pulmonary vein as it enters the left atrium (LA). (Right) Posteriorly directed oblique MRA MIP from the same patient shows a focal stenosis of the left superior pulmonary vein as the vein enters the left atrium. P.10:9

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Diagnostic Imaging Cardiovascular TERMINOLOGY Definitions Narrowed pulmonary vein (PV) after radiofrequency catheter ablation (RFCA) for atrial fibrillation or secondary to adjacent mass or lymphadenopathy Congenital stenosis of pulmonary vein in isolation or associated with congenital heart disease IMAGING General Features Best diagnostic clue Direct visualization of narrowing on cross-sectional imaging Location Any treated PVs; left inferior pulmonary vein ostia is most susceptible to effects of RFCA Size Mild diameter stenosis < 50%, severe > 70% Radiographic Findings Radiography Edema in lung drained by stenotic PV CT Findings CECT Direct visualization of PV stenosis with CT Pitfall: Normal oval shape may mimic stenosis; comparison with pretreatment images helpful Delayed contrast enhancement of affected veins and corresponding pulmonary arteries ± pulmonary signs of venous hypertension in affected lung Interlobular septal thickening and ground-glass opacity MR Findings MRA Direct visualization of PV stenosis Can use velocity-encoded cine phase contrast to measure velocity or flow Echocardiographic Findings Echocardiogram TEE may show increased PV velocity, turbulent flow at junction of PV and left atrium (LA), and stenosis Often limited to superior PVs Angiographic Findings Conventional Pulmonary angiography may reveal pruning of peripheral arteries, delayed transit of contrast through lungs to LA, and PV stenosis itself Imaging Recommendations Best imaging tool CTA Protocol advice Bolus timing to LA DIFFERENTIAL DIAGNOSIS Pulmonary Vein Thrombosis Visualization of thrombus in lumen of PV Lack of visualization of previously seen vein ± wedge-shaped lung consolidation reflecting venous infarction Pulmonary Vein Varix Fusiform dilation No narrowing at junction with LA when diameter is compared with that of similarly sized veins PATHOLOGY General Features Etiology Risk factors include RFCA inside PVs rather than around ostia, use of excessive power RFCA may induce swelling (early) and fibrosis (late) Lung cancer or, rarely, inflammatory pseudotumor CLINICAL ISSUES Presentation Most common signs/symptoms Frequently asymptomatic if single vein is involved Dyspnea, cough, hemoptysis, pleuritic pain 855

Diagnostic Imaging Cardiovascular Other signs/symptoms Bilateral congenital pulmonary vein stenosis Recurrent infections, failure to thrive, hemoptysis, pulmonary hypertension Demographics Epidemiology Incidence from 3-42% depending on RF technique, imaging technique, definition of stenosis Rate falling because of RFCA is delivered around ostia rather than within PVs Stenosis secondary to lung cancer is usually associated with a mass or lymphadenopathy Congenital pulmonary vein stenosis is rare Natural History & Prognosis If stenosis occurs post RFCA, ˜ 10% progress and ˜ 10% regress Treatment Symptomatic patients or asymptomatic patients with severe stenosis can be treated with balloon angioplasty and stent deployment Rationale for treating asymptomatic patient: Unknown risk of pulmonary hypertension; risk of progression to complete occlusion ˜ 50% restenose, prompting further intervention SELECTED REFERENCES 1. Vyas HV et al: MR imaging and CT evaluation of congenital pulmonary vein abnormalities in neonates and infants. Radiographics. 32(1):87-98, 2012 2. Holmes DR Jr et al: Pulmonary vein stenosis complicating ablation for atrial fibrillation: clinical spectrum and interventional considerations. JACC Cardiovasc Interv. 2(4):267-76, 2009 3. Cronin P et al: MDCT of the left atrium and pulmonary veins in planning radiofrequency ablation for atrial fibrillation: a how-to guide. AJR Am J Roentgenol. 183(3):767-78, 2004 4. Ghaye B et al: Percutaneous ablation for atrial fibrillation: the role of cross-sectional imaging. Radiographics. 23 Spec No:S19-33; discussion S48-50, 2003 P.10:10

Image Gallery

(Left) Coronal MRA shows a mild asymptomatic stenosis of the left superior pulmonary vein. This patient was status post radiofrequency ablation on 3 separate occasions for refractory atrial fibrillation. (Right) Frontal 3D volumerendered image of the left atrium and pulmonary veins shows successful stenting of the proximal left superior pulmonary vein and a lingular branch following symptomatic pulmonary vein stenosis after radiofrequency ablation.

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(Left) Axial CTA shows a focal stenosis of the left inferior pulmonary vein ostium following radiofrequency ablation. The left atrium is enlarged. (Right) Axial cardiac CT in the same patient 1 month later shows interval left inferior pulmonary vein occlusion . The patient had undergone multiple episodes of radiofrequency ablation for recurrent atrial fibrillation. Delayed images can help differentiate occlusions from slow contrast transition due to severe stenosis.

(Left) Posterior 3D volume-rendered image of the left atrium and pulmonary veins from the CTA (same patient) shows left inferior pulmonary vein occlusion . There is a mild stenosis of the right inferior pulmonary vein. (Right) Coronal CECT shows abnormal soft tissue encasing and narrowing the right superior pulmonary vein . There is chunky calcification within the soft tissue mass in this case of fibrosing mediastinitis from histoplasmosis. P.10:11

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(Left) Axial cardiac CT shows narrowing at the ostium of the left inferior pulmonary vein . (Right) Axial cardiac CT from the same patient shows abnormal soft tissue extending from the left hilar region, anterior to the left mainstem bronchus . This soft tissue extends to the superior aspect of the left atrium. No left superior pulmonary vein is visualized. There is extensive consolidation in the left upper lobe and lingula thought to represent venous infarction.

(Left) Oblique axial cardiac CT at the level of the inferior pulmonary vein from the same patient shows a stent with resolution of stenosis. The stenosis was a complication of radiofrequency ablation. (Right) Axial cardiac CT from the same patient shows nearly complete resolution of the left upper lobe and lingular consolidation following stent placement. The consolidation was felt to be due to venous infarction.

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(Left) Oblique coronal CECT shows narrowing of the left inferior pulmonary vein caused by adjacent soft tissue thickening. (Right) Oblique CECT in the same patient 6 months later shows occlusion of the left inferior pulmonary vein caused by an adjacent infiltrative mass representing a lung cancer. Note soft tissue surrounding the left lower lobe bronchus.

Pacemakers/ICDs Key Facts Terminology Pacemakers: Electronic devices connected to the heart by pacing wires that use electrical impulses to regulate cardiac rate or rhythm Implantable cardioverter-defibrillators (ICDs): Electronic devices that administer electric shocks to heart to restore normal cardiac rhythm if defined rapid ventricular arrhythmias are sensed Imaging Typical appearance on radiography ICD leads are thicker than pacemaker leads Generator will overlie left or right anterior chest wall in most cases CT allows for more detailed evaluation of lead integrity Leads may fracture, typically between 1st rib and clavicle Pathology ACC/AHA guidelines for ICD therapy include as class I indications Cardiac arrest due to ventricular fibrillation (VF) or tachycardia (VT) Spontaneous sustained VT Syncope with inducible VT or VF in electrophysiological (EP) study Nonsustained VT in setting of ischemic heart disease and inducible VF or VT in EP study Indications for permanent pacing therapy include, among others Certain atrioventricular blocks Sinus node dysfunction with bradycardia ± symptoms Hypertrophic or dilated cardiomyopathies with sinus node dysfunction Neurocardiogenic syncopes

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(Left) Magnified posteroanterior radiograph shows the typical location of a defibrillator lead terminating in the right ventricle. The defibrillator electrodes are typically in the superior vena cava and the right ventricle , with the sensing electrode at the tip . (Right) Lateral radiograph shows the typical course of a defibrillator lead. The defibrillator leads are in superior vena cava and the right ventricle , and the sensing electrode is at the right ventricular tip .

(Left) Frontal radiograph shows a high-voltage defibrillator catheter in the azygos vein . The characteristic redundant appearance of the lead at the en face portion of the azygos vein is essentially diagnostic of an azygos position. (Right) Lateral radiograph shows the typical course of a lead in the azygos vein . The advantage of this position is a discharge across the left ventricular mass. A right atrial appendage lead and right ventricular lead are also present. P.10:13

TERMINOLOGY Abbreviations Implantable cardioverter-defibrillator (ICD) Automatic implantable cardioverter-defibrillator (AICD) Synonyms Permanent pacing device Definitions Pacemakers Permanently implanted battery-operated electronic devices connected to the heart by pacing wires that use electrical impulses to regulate cardiac rate or rhythm 860

Diagnostic Imaging Cardiovascular Substitute for natural pacemaker (sinus node) ICDs Permanently implanted battery-operated electronic devices that administer electric shocks via intracardiac or epicardial leads to the heart to restore normal cardiac rhythm if defined rapid ventricular arrhythmias are sensed IMAGING General Features Best diagnostic clue Presence of epicardial, coronary sinus, or right atrial and ventricular leads Presence of pacemaker or ICD generator Location Usually right or left pectoral pocket containing device generator Older devices and epicardial pacing or defibrillator devices in abdominal wall tissue Temporary leads may have leads exit at right internal jugular vein and connect to extracorporal device Leads typically ascend in superior vena cava and right or left innominate and subclavian veins Older leads may descend in subcutaneous tissue toward abdomen Epicardial leads typically perforate pericardium anteriorly and descend toward abdomen within connective tissue Lead tip locations Right atrium, commonly atrial appendage Right ventricle near apex Left ventricle Via coronary sinus in great cardiac vein or its tributaries (transvenous leads) Via pericardium within epicardial myocardium (epicardial leads) Size Lead size varies: 1-3 mm ICD leads are generally thick Typically have 2 separate thickened areas with spring coil appearance that deliver electrical shocks when triggered Morphology Single-chamber pacing 1 lead: Either in right atrium or in right ventricle Dual-chamber pacing 2 leads: 1 in right atrium and 1 in right ventricle Biventricular pacing 3 leads: 1 in right atrium, 1 in right ventricle, and 1 via coronary sinus in great cardiac vein or tributary Epicardial pacing 2 screw-in leads in left ventricular myocardium Device location: Abdominal wall Epicardial defibrillator 2 patches over anterior right ventricle and posterior lateral left ventricle Device location: Abdominal wall ICD 1 multifunctional lead Defibrillator electrodes at superior vena cava and right ventricle level Sensing electrode at lead tip of right ventricle ± coronary sinus lead and right atrial lead if also biventricularly paced Radiographic Findings May demonstrate Lead fractures Tip dislodgement Device migration Fluoroscopic Findings Fluoroscopy may be helpful in confirming lead fractures with only little fragment displacement Typically between 1st rib and clavicle Upper extremity maneuvers may be useful in visualization of lead fractures CT Findings CECT 861

Diagnostic Imaging Cardiovascular CT may demonstrate complication from device placement Hemothorax Pneumothorax or pneumopericardium Chamber or coronary sinus rupture with hemopericardium ± tamponade Device infection Wide window will allow for more accurate visualization of leads Sharper kernel reconstruction theoretically reduces streak artifact around leads Iterative reconstruction is helpful in reducing streak artifact around leads Most accurate visualization of leads on CT is achieved using ECG gating or triggering High temporal resolution CT scanners now often halt cardiac motion without ECG gating or triggering Ultrasonographic Findings Ultrasound with Doppler sonography is useful to detect venous thrombosis Useful to evaluate device infection or seroma formation Interrogation of tissue behind generator may be limited by immobile device and acoustic shadowing Dependent on operator skill Imaging Recommendations Best imaging tool Posteroanterior and lateral radiograph Protocol advice Fluoroscopy may confirm suspected lead fracture P.10:14

DIFFERENTIAL DIAGNOSIS Deep Brain Stimulator Treatment of Parkinson disease Leads travel toward cranium May involve multiple devices Vagal Nerve Stimulator Leads terminate in neck near carotid arteries Spinal Cord Stimulators 1 or 2 leads with multiple electrodes (4-6) Leads in epidural space of lower thoracic and upper lumbar spine Other Pacemakers and Stimulators Diaphragmatic pacemaker Gastric stimulator Bladder pacemaker PATHOLOGY General Features Class I indications included in American College of Cardiology/American Heart Association guidelines for ICD therapy Cardiac arrest due to ventricular fibrillation or tachycardia not due to transient cause Spontaneous sustained ventricular tachycardia Syncope with inducible ventricular tachycardia or ventricular fibrillation in electrophysiological study Nonsustained ventricular tachycardia in setting of ischemic heart disease and inducible ventricular fibrillation or tachycardia in electrophysiological study Other indications for ICD treatment include, among others Ventricular tachycardia while awaiting transplant Familial conditions such as hypertrophic cardiomyopathy or long QT syndrome Indications for permanent pacing therapy include, among others Acquired atrioventricular block with bradycardia, arrhythmia, asystole > 3 seconds, or after surgery or ablation procedures Bifascicular or trifascicular atrioventricular blocks Sinus node dysfunction with bradycardia ± symptoms Hypertrophic or dilated cardiomyopathies with sinus node dysfunction Neurocardiogenic syncopes Gross Pathologic & Surgical Features Intraoperative placement of epicardial leads should consider phrenic nerve course to avoid phrenic stimulation Coronary sinus lead preferred over epicardial location for biventricular pacing 862

Diagnostic Imaging Cardiovascular Implantation of epicardial leads still necessary if No suitable coronary vein is identified Coronary sinus placement has failed Screw-in leads are leads of choice in epicardial pacing Development of epicardial fibrosis often leads to increases in pacing thresholds Epicardial leads may lead to postoperative pericardial adhesions Video-assisted thoracic surgical placement is available but carries risks related to single-lung ventilation Epicardial defibrillator patches were more commonly used in the past May migrate or cause excessive fibrosis or fluid collections CLINICAL ISSUES Presentation Complications Cardiac perforation or coronary sinus transsection Pneumothorax &/or pneumopericardium Dislodgement of leads Hemothorax, pleural effusions Infection of pacer generator or ICD &/or leads Stimulation of diaphragm via phrenic nerve Device migration Old leads are frequently left in place when generator is replaced Treatment In heart failure patients, a resynchronization-defibrillator combination device coupled with optimal medical therapy reduces all-cause mortality by 43% DIAGNOSTIC CHECKLIST Consider Carefully follow course of leads as fractures may be nondisplaced and subtle Compare lead position with initial post-placement radiograph to exclude lead migration Image Interpretation Pearls Beam hardening artifact may mimic right ventricular perforation by lead tip Absence of pericardial fluid in absence of clinical symptoms suggests absence of free perforation SELECTED REFERENCES 1. Costelloe CM et al: Radiography of pacemakers and implantable cardioverter defibrillators. AJR Am J Roentgenol. 199(6):1252-8, 2012 2. Chen HY: Delayed isolated hemothorax caused by temporary pacemaker: a case report. Int J Cardiol. 114(3):e10910, 2007 3. Levin G et al: Noncardiac implantable pacemakers and stimulators: current role and radiographic appearance. AJR Am J Roentgenol. 188(4):984-91, 2007 4. Martinek M et al: Pneumopericardium followed by pericardial effusion after thoracic trauma and pacemaker implantation. Herz. 31(6):592-3, 2006 5. Ellery SM et al: Complications of biventricular pacing. Eur. Heart J. Suppl. 6(D):D117-21, 2004 6. Kühlkamp V et al: Initial experience with an implantable cardioverter-defibrillator incorporating cardiac resynchronization therapy. J Am Coll Cardiol. 39(5):790-7, 2002 7. Ho WJ et al: Right pneumothorax resulting from an endocardial screw-in atrial lead. Chest. 116(4):1133-4, 1999 P.10:15

Image Gallery

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(Left) PA radiograph shows a 3-lead automated implantable cardiac defibrillator (AICD) with 1 lead in the right atrium , 1 lead in the right ventricle , and 1 lead in the coronary sinus . The right ventricular lead extends more laterally than expected, which is worrisome for cardiac perforation. (Right) Coronal oblique CT image shows that the right ventricular lead has perforated through the right ventricle and pericardium and lies within the epicardial fat.

(Left) AP radiograph shows a right ventricular lead and malpositioned lead outside the expected confines of the heart. There are bibasilar pulmonary opacities (likely a combination of pulmonary edema and atelectasis) and pleural effusions. (Right) Axial NECT shows that the right atrial lead has penetrated the atrium and extends to the anterior chest wall. The right ventricular lead is again in its expected location. Incidental note is made of calcified splenic granulomas.

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(Left) Frontal radiograph after implantation of cardiac defibrillator shows 3 leads in a cardiac vein , right atrium , and right ventricle . (Right) A follow-up radiograph after development of chest pain demonstrates prolapse of the cardiac vein lead into the right ventricle and main pulmonary artery, although the tip is in an unchanged position. The right atrial and ventricular leads are unchanged and within expected locations for such leads.

Cardiac Vein Mapping Key Facts Terminology Cardiac gated CT angiogram with contrast injection protocol tailored to optimize coronary venous enhancement Imaging CTA is best noninvasive imaging test Cardiac veins are located within epicardial fat and drain into right atrium Coronary sinus and great cardiac vein travel in left atrioventricular groove Middle cardiac vein and anterior interventricular vein travel in posterior and anterior interventricular grooves Diagonal, marginal, and posterior left ventricular tributaries are located on anterior, lateral, and inferior left ventricular surfaces Top Differential Diagnoses Coronary artery to coronary vein fistula Unroofed coronary sinus Diagnostic Checklist CT allows evaluation for presence of suitable veins for coronary sinus lead placement Alternatively, CT may be used for coronary arterial and venous anatomy delineation prior to surgical epicardial pacemaker lead placement Helps guide placement and avoid vascular injury Used to guide complex electrophysiology procedures (e.g., transcoronary venous or pericardial catheter ablation of ventricular fibrillation foci) Consider adding ˜ 8 seconds to delay time for optimal venous enhancement

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(Left) Oblique cardiac CT MIP image shows a large marginal vein in posterior lateral left ventricular epicardial fat and draining into the coronary sinus . (Right) Posterior 3D cardiac CT shows a coronary sinus and great cardiac vein paralleling the left circumflex coronary artery , marginal and posterior veins of left ventricle , and middle cardiac vein . (RA = right atrium.)

(Left) Anterior view cardiac CT volume rendering shows coronary arterial tree and coronary venous system. Note the coronary sinus , middle cardiac vein , and marginal vein . (Right) Axial cardiac CT shows the middle cardiac vein entering the coronary sinus close to its connection to the right atrium. Note the very small posterior vein of left ventricle paralleling the posterior left ventricular artery. P.10:17

TERMINOLOGY Synonyms CT cardiac venography Definitions Cardiac gated CT angiogram with contrast injection protocol tailored to optimize coronary venous enhancement IMAGING General Features Location Cardiac veins are located within epicardial fat and drain into right atrium Coronary sinus and great cardiac vein travel in left atrioventricular groove Middle cardiac vein and anterior interventricular vein travel in posterior and anterior interventricular grooves 866

Diagnostic Imaging Cardiovascular Diagonal, marginal, and posterior left ventricular tributaries are located on anterior, lateral, and inferior left ventricular surfaces Morphology Cardiac venous anatomy is very variable Coronary sinus is consistently present (˜ 100%) Middle cardiac vein or “posterior interventricular vein” is consistently present Posterior vein of left ventricle is variable (present in 80-90%) Great cardiac vein is consistently present Marginal vein or lateral vein (present in 70-90%) is often multiple Anterior interventricular vein is consistently present Small cardiac veins is present in ˜ 10% Anterior cardiac veins is present in ˜ 40% Imaging Recommendations Best imaging tool CTA is best noninvasive imaging test Invasive retrograde angiography prior to biventricular pacer placement Rotational angiography is promising new tool Protocol advice Coronary CT protocol needs to be adjusted to allow for capturing coronary venous phase Best venous enhancement occurs ˜ 8-15 seconds after initial arterial enhancement DIFFERENTIAL DIAGNOSIS Coronary Artery to Coronary Vein Fistula Abnormal connection between epicardial artery and veins Usually dilated and tortuous arteries and coronary sinus Unroofed Coronary Sinus Abnormal connection between coronary sinus and left atrium Causes left-to-right shunt (left atrium into coronary sinus into right atrium) Rarest type of atrial septal defects PATHOLOGY Staging, Grading, & Classification 2 main groups: Tributaries of greater and lesser cardiac venous systems Greater (70%) Epicardial drainage Coronary sinus tributaries (e.g., coronary sinus, great cardiac vein, oblique vein of Marshall, posterior interventricular veins) Noncoronary sinus tributaries (e.g., anterior right ventricular vein, left and right atrial veins, superior septal veins) Lesser (30%) Subendocardial or intramural drainage Thebesian veins (or vessels) Embryology Right and left common cardinal veins form from anterior and posterior cardinal veins Right horn of coronary sinus forms posterior wall of right atrium Right common cardinal vein forms superior vena cava Left horn of coronary sinus and left common cardinal vein form coronary sinus and vein of Marshall DIAGNOSTIC CHECKLIST Consider CT allows evaluation for presence of suitable veins for coronary sinus lead placement Alternatively, CT may be used for coronary arterial and venous anatomy delineation prior to surgical epicardial pacemaker lead placement Helps guide placement and avoid vascular injury May be used to guide complex electrophysiology procedures, such as transcoronary venous or transpericardial catheter ablation of ventricular fibrillation foci within myocardium; or placement of cardiac resynchronization devices Image Interpretation Pearls Consider adding ˜ 8 seconds to delay time for optimal venous enhancement Requires increase in contrast volume, calculated by multiplying injection rate in milliliters by 8 seconds SELECTED REFERENCES

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Diagnostic Imaging Cardiovascular 1. Saremi F et al: Coronary veins: comprehensive CT-anatomic classification and review of variants and clinical implications. Radiographics. 32(1):E1-32, 2012 2. Rosen BD et al: The expanding role of computed tomography in the assessment of coronary artery disease and cardiac anatomy. Trends Cardiovasc Med. 21(7):193-9, 2011 3. Abbara S et al: Noninvasive evaluation of cardiac veins with 16-MDCT angiography. AJR Am J Roentgenol. 185(4):1001-6, 2005 4. Jongbloed MR et al: Noninvasive visualization of the cardiac venous system using multislice computed tomography. J Am Coll Cardiol. 45(5):749-53, 2005 5. Muhlenbruch G et al: Imaging of the cardiac venous system: comparison of MDCT and conventional angiography. AJR Am J Roentgenol. 185(5):1252-7, 2005

Left Atrial Thrombus Key Facts Terminology Thrombus formation in left atrial appendage (LAA) or occasionally in body of left atrium Usually due to atrial fibrillation or mitral valve stenosis Imaging Best diagnostic clue: Filling defect within LAA Transesophageal echocardiography (TEE) is considered gold standard for excluding LAA thrombus Radiography Usually no signs on PA radiograph Cardiac CTA Low Hounsfield unit (HU) filling defect suggests thrombus HU > 80 in LAA more likely represents slow mixing Sharper interface between filling defect and contrast opacified lumen is suggestive of thrombus Delayed scans allow for differentiation of slow mixing and real LAA thrombus Cardiac MR White blood imaging in multiple planes helps outline thrombus, especially in body of left ventricle Gadolinium-enhanced MR is inferior to TEE for detection of LAA thrombus Top Differential Diagnoses Pseudo thrombus (on CTA) Tumors Surgical exclusion of LAA Clinical Issues Treatment Anticoagulant therapy (warfarin) substantially reduces embolic event risk Surgical: Maze procedure and similar operations LAA obliteration

(Left) Axial oblique CTA shows a hypodense filling defect in the left atrial appendage . The body of the left atrium is dilated and balloon-like due to atrial fibrillation . (Right) Vertical long-axis CTA from the same patient shows a thrombus within the left atrial appendage . The body of the left atrium is markedly dilated relative to the left 868

Diagnostic Imaging Cardiovascular ventricle. Atrial fibrillation and mitral stenosis are the most common causes of left atrial thrombus formation.

(Left) Axial cardiac CT shows a relatively well defined filling defect in the nondependent portion of the left atrial appendage, suggesting a possible thrombus. (Right) Axial cardiac CT delayed scans in the same patient show complete contrast filling of the left atrial appendage , indicating absence of thrombus and slow mixing across the left atrial appendage. This case illustrates the value of delayed scans to confirm the presence or absence of left atrial appendage thrombus. P.10:19

TERMINOLOGY Definitions Thrombus formation in left atrial appendage (LAA) or occasionally in body of left atrium Usually due to atrial fibrillation or mitral valve stenosis IMAGING General Features Best diagnostic clue Filling defect within LAA Persistent on delayed contrast-enhanced CT scan Location Usually in LAA Occasionally in body of left atrium Size Variable Morphology Chronic broad-based thrombus may develop neovascularization, which will lead to low-grade enhancement on contrast-enhanced MR May present diagnostic challenge when differentiating chronic thrombus from malignancy Radiographic Findings Usually no signs on PA radiograph May demonstrate convexity of LAA segment of left heart border May demonstrate signs of underlying condition Mitral valve stenosis Pulmonary venous hypertension (Kerley B lines, pulmonary vein redistribution, pulmonary edema) Right retrocardiac double density (enlarged left atrium) Splaying of carina (enlarged left atrium) Convex LAA segment Convex pulmonary artery segment if secondary pulmonary arterial hypertension (chronic mitral stenosis only) CT Findings CTA 869

Diagnostic Imaging Cardiovascular Thoracic CTA may incidentally demonstrate LAA thrombus Thin-cut reconstructions and delayed scans are most helpful in demonstrating persistent filling defect Pitfall: Motion or pulsation artifact Cardiac gated CTA Low Hounsfield unit (HU) filling defect is suggestive of thrombus Sharper interface between filling defect and contrast-opacified lumen is suggestive of thrombus HU > 80 in LAA more likely represents slow mixing Delayed scans allow for differentiation of slow-mixing artifact from LAA thrombus May show findings of underlying mitral valve disease When differentiating thrombus from malignancy, CTA enhancement is less helpful than MR enhancement Cardiac CTA is useful for anatomic metrics and exclusion of thrombus prior to percutaneous occlusion device implantation Follow-up scans may be used to confirm proper device placement and exclude residual perfusion Cardiac CTA is used for anatomic guidance of pulmonary vein radiofrequency (or cryo-) ablation or isolation to treat atrial fibrillation Fusion of electroanatomic maps with CTA data sets is used as road map Mid-expiration CT imaging is preferred when fusion is performed (electroanatomic mapping performed during free breathing) MR Findings Gadolinium-enhanced MR is inferior to transesophageal echocardiography for detection of LAA thrombus White blood imaging in multiple planes is helpful for outlining thrombus, especially if in body of left ventricle T1WI SE without and with gadolinium is best test for assessing enhancement of mass 1st-pass perfusion and delayed-enhancement acquisitions may also demonstrate absence of enhancement of large left atrium (body) or left ventricle thrombi MR may be used for atrial appendage occlusion device placement planning MR is used for pulmonary vein ablation/isolation procedures Echocardiographic Findings Echocardiogram Transesophageal echocardiography is considered gold standard for excluding LAA thrombus Spontaneous echo contrast or “smoke” and other artifacts may hamper identification or exclusion of LAA thrombus Visualization of LAA thrombus may be improved with use of thrombus-targeting ultrasonographic contrast agent (MRX-408A1) Imaging Recommendations Best imaging tool Transesophageal echocardiography Cardiac CT with delayed-phase scan is promising tool Prone imaging may be helpful to differentiate thrombus from slow mixing Protocol advice CTA delayed scan reduces false-positive findings from slow mixing DIFFERENTIAL DIAGNOSIS Pseudo Thrombus (on CTA) Low attenuation within LAA due to slow mixing of contrast containing blood with nonopacified blood More common in atrial fibrillation and poor LAA ejection fraction Tumors Myxoma Metastasis Primary malignancy Surgical Exclusion of Left Atrial Appendage Performed after valve surgery to prevent LAA thrombosis P.10:20

PATHOLOGY General Features Etiology 870

Diagnostic Imaging Cardiovascular Atrial fibrillation Mitral valve disease of any cause Left atrial thrombus formation on atrial septal defect occluder systems has been reported Associated abnormalities Often source of neurologic events or large artery occlusion Cardiac (left atrial or ventricular) thrombus has to be excluded in absence of otherwise identifiable source of embolic (cryptogenic) stroke or transient ischemic attack If negative, patent foramen ovale (PFO) and deep vein thrombosis (DVT) need to be excluded Lower extremity ultrasound and pelvic MR venography are used to exclude DVT in patients with PFO and cryptogenic stroke CLINICAL ISSUES Presentation Most common signs/symptoms Asymptomatic Cryptogenic stroke Other embolic events Other signs/symptoms Symptoms or imaging findings from underlying disease Atrial fibrillation Mitral valve disease In rheumatic mitral stenosis Presence of coarse F waves on ECG is associated with LAA dysfunction Presence indicates higher thromboembolic risk Demographics Age Age range parallels that of underlying conditions Gender M=F Natural History & Prognosis May persist without complication May embolize to brain causing transient ischemic attack or stroke May resolve spontaneously Recurrence common if underlying cause not treated Treatment Anticoagulant therapy (warfarin) substantially reduces embolic event risk in atrial fibrillation from LAA thrombus Needs frequent INR monitoring & carries bleeding risk Other drugs may have clinical roles in select cases Dabigatran and rivaroxaban Antiplatelet therapy ± low-dose warfarin, etc. Surgical: Maze procedure and similar operations Catheter-based radiofrequency ablation (pulmonary vein isolation) Prevention of thrombus formation LAA obliteration Surgical or catheter based occlusion device DIAGNOSTIC CHECKLIST Consider 1-minute delayed gated scan to follow CTA or CTV if filling defect is noted on initial images Slow mixing of opacified and nonopacified blood across neck of LAA may mimic thrombus on arterialphase gated CT Delayed scan allows for more complete mixing If filling defect persists, thrombus is present If LAA fills with contrast, there is slow flow artifact (equivalent to smoke on transesophageal echocardiography) SELECTED REFERENCES 1. Balli O et al: Multidetector CT of left atrium. Eur J Radiol. 81(1):e37-46, 2012 2. Daccarett M et al: MRI of the left atrium: predicting clinical outcomes in patients with atrial fibrillation. Expert Rev Cardiovasc Ther. 9(1):105-11, 2011 3. Gorodnitskiy A et al: A novel approach to left atrial appendage exclusion: the WATCHMAN device. Cardiol Rev. 18(5):230-3, 2010 871

Diagnostic Imaging Cardiovascular 4. Qamruddin S et al: Left atrial appendage: structure, function, imaging modalities and therapeutic options. Expert Rev Cardiovasc Ther. 8(1):65-75, 2010 5. Hesse B et al: Images in cardiovascular medicine. A left atrial appendage thrombus mimicking atrial myxoma. Circulation. 113(11):e456-7, 2006 6. Mohrs OK et al: Percutaneous left atrial appendage transcatheter occlusion (PLAATO): planning and follow-up using contrast-enhanced MRI. AJR Am J Roentgenol. 186(2):361-4, 2006 7. Mohrs OK et al: Thrombus detection in the left atrial appendage using contrast-enhanced MRI: a pilot study. AJR Am J Roentgenol. 186(1):198-205, 2006 8. Parekh A et al: Images in cardiovascular medicine. The case of a disappearing left atrial appendage thrombus: direct visualization of left atrial thrombus migration, captured by echocardiography, in a patient with atrial fibrillation, resulting in a stroke. Circulation. 114(13):e513-4, 2006 9. Blackshear JL et al: Stroke prevention in atrial fibrillation: warfarin faces its challengers. Curr Cardiol Rep. 7(1):1622, 2005 10. Mutlu B et al: Fibrillatory wave amplitude as a marker of left atrial and left atrial appendage function, and a predictor of thromboembolic risk in patients with rheumatic mitral stenosis. Int J Cardiol. 91(2-3):179-86, 2003 11. Nakai T et al: Percutaneous left atrial appendage occlusion (PLAATO) for preventing cardioembolism: first experience in canine model. Circulation. 105(18):2217-22, 2002 12. von der Recke G et al: Transesophageal contrast echocardiography distinguishes a left atrial appendage thrombus from spontaneous echo contrast. Echocardiography. 19(4):343-4, 2002 13. von der Recke G et al: Use of transesophageal contrast echocardiography for excluding left atrial appendage thrombi in patients with atrial fibrillation before cardioversion. J Am Soc Echocardiogr. 15(10 Pt 2):1256-61, 2002 14. Sim EK et al: Co-existing left atrial thrombus and myxoma in mitral stenosis—a diagnostic challenge. Singapore Med J. 40(1):46-7, 1999 15. Takeuchi M et al: Enhanced visualization of intravascular and left atrial appendage thrombus with the use of a thrombus-targeting ultrasonographic contrast agent (MRX-408A1): In vivo experimental echocardiographic studies. J Am Soc Echocardiogr. 12(12):1015-21, 1999 P.10:21

Image Gallery

(Left) Vertical long-axis SSFP cine sequence show a heterogeneous mass along the posterior wall of the left atrium , consistent with a thrombus. The thrombus is primarily intermediate in signal, although patchy areas of increased signal are present. The left atrium is moderately dilated. (Right) Four-chamber inversion-recovery image obtained 10 minutes after the administration of gadolinium shows no enhancement within the thrombus, which is very dark in signal .

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(Left) Axial nongated CECT shows a well-defined filling defect in the tip of the left atrial appendage, suggesting the presence of a thrombus. (Right) Cardiac CT of pulmonary veins shows a filling defect in the tip of the left atrial appendage, suggestive of a thrombus. Further evaluation with delayed CT scanning or echocardiography is necessary to differentiate the thrombus from slow filling of contrast into the left atrial appendage.

(Left) Long-axis contrast-enhanced CTA shows occlusion of the left atrial appendage by a left atrial appendage closure (Watchman) device . (Right) VR contrast-enhanced CTA in the same patient shows occlusion of the left atrial appendage by a left atrial appendage closure (Watchman) device . Left atrial appendage closure device is used in patients with atrial fibrillation in order to decrease the risk of distal embolization.

Section 11 - Pulmonary Vasculature Approach to Pulmonary Vasculature Introduction The pulmonary arteries (PAs) are responsible for transporting deoxygenated blood from the right ventricle to the lungs where gas exchanges occur through the capillaries. The pulmonary veins (PVs) are responsible for draining oxygenated blood to the left atrium. Pathologies of the pulmonary vasculature often result in nonspecific symptoms, such as dyspnea, chest pain, or a decrease in exercise tolerance. Some of these abnormalities can also be asymptomatic and incidentally detected on imaging. It is incumbent on the radiologist to examine the pulmonary vasculature carefully on every imaging study where it is visualized, such as on chest radiography and chest or cardiac CT and MR. The main abnormalities of PA and PV detected on cross-sectional imaging include abnormal diameters and filling defects. Congenital structural abnormalities of the pulmonary vasculature also occur. Imaging Protocols 873

Diagnostic Imaging Cardiovascular The PAs are best imaged by multidetector CT with CT pulmonary angiography protocols. It is the imaging study of choice for diagnosis of pulmonary embolism in most patients. CT pulmonary angiography is also the preferred protocol in patients suspected of having pulmonary arteriovenous malformation, PA aneurysm, or pseudoaneurysm. Optimal contrast enhancement of the PA system can be achieved by using an automated bolus-tracking technique or a small test bolus injection by placing a region of interest in the main PA or right ventricle. With introduction of multidetector CT, the amount of intravenous contrast material used can be reduced to the range of 30-80 mL with injection rate of 3-5 mL/s. Scanning at reduced tube voltage combined with iterative reconstruction techniques allows greater contrast attenuation without reducing the diagnostic quality of the data set. The PVs are best opacified by contrast in a more delayed phase compared to the PAs. With most routine contrastenhanced chest CT protocols, the PVs are well opacified. MR pulmonary angiography can also be performed in selected patient population. Imaging Anatomy Pulmonary Arteries The pulmonary trunk arises from the right ventricle and courses anterior and to the left of the ascending aorta. It bifurcates into the right and left main PAs. The right PA then bifurcates into the truncus anterior, which supplies the right upper lobe, and the right interlobar PA, which further divides into the right middle and right lower lobar branches. Similarly, the left main PA bifurcates into the left upper lobar PA and left interlobar PA, which divides into the lingular and left lower lobar branches. There are ten segmental branches in the right lung and eight segmental branches in the left. PAs course adjacent to the bronchi and bronchioles. Within the lungs, the pulmonary arterioles are centrilobular in location. Congenital anatomical abnormalities of the PA include pulmonary sling and proximal interruption of PA. Pulmonary Veins In ˜ 70% of individuals, four separate PVs (a superior and an inferior PV on each side) are present, each with a separate ostium as they join the left atrium. Common ostium for the superior and inferior PVs typically occurs on the left side. Supernumerary PVs can also be seen. Within the lungs, the PVs run along the periphery of the secondary pulmonary lobules with the pulmonary lymphatics. Congenital anatomical abnormalities of PV include partial and total anomalous pulmonary venous return, which results in left-to-right shunts. Abnormalities in Vascular Diameter Dilated Pulmonary Artery Dilated PA can be seen in a number of disease entities. Pulmonary arterial hypertension is one of the most common causes of dilatation of the main pulmonary trunk. Depending on the cause of pulmonary hypertension, the more distal branches may be dilated or pruned. In cases of idiopathic pulmonary hypertension, pruning of the more distal PA branches is often seen. If pulmonary hypertension is related to left-to-right shunt and overperfusion of the pulmonary circulation, the segmental and subsegmental PA branches are often dilated. In patients with pulmonary hypertension, dilatation of the right atrium and right ventricle with leftward deviation of the interventricular septum can also be observed on cross-sectional imaging. When a dilated main PA is associated with pulmonary findings of pulmonary edema (ground-glass opacities, interlobular septal thickening, pleural effusions), pulmonary venoocclusive disease should be suspected. In pulmonary venoocclusive disease, fibrosis or occlusion of small venules (below the resolution of CT) results in pulmonary hypertension. Dilated pulmonary trunk with asymmetric dilatation of the left main PA is seen in the setting of pulmonary stenosis. The direction of the jet through the stenotic valve results in asymmetric dilatation of the left main PA. Less common causes of PA dilatation include PA aneurysms and pseudoaneurysms. These entities are often difficult to distinguish from each other based on imaging as both manifest as dilatation of the PA branch. Both can cause significant hemoptysis in the event of rupture. Aneurysms are often more fusiform in shape, and pseudoaneurysms tend to be saccular. PA aneurysms are frequently seen in the setting of pulmonary hypertension and left-to-right shunt. Multiple PA aneurysms are found in patients with Behçet disease and Hughes-Stovin syndrome. PA pseudoaneurysms are often iatrogenic, related to use of PA catheter or thoracic procedures. Pulmonary infection is also a significant cause of PA pseudoaneurysm. Dilated PA branch can also be seen in the setting of pulmonary arteriovenous malformation, where the feeding artery is dilated. Identification of the draining vein is key to making this diagnosis. Narrowing of Pulmonary Artery PA stenosis with focal or tubular narrowing of the involved PA can be congenital or acquired. Congenital PA stenosis, often detected in pediatric patients, is usually associated with congenital heart disease or clinical syndromes, such as Noonan or Williams syndrome. In adults, PA stenosis can be related to chronic PA thromboembolism and vasculitis. Stenoses at the anastomosis site after surgery and mediastinal fibrosis, P.11:3 often related to granulomatous infection, are less common causes of PA stenosis.

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Diagnostic Imaging Cardiovascular External compression by primary or metastatic neoplasms or lymphadenopathy is also a common cause of narrowing of the PA. CTA and MRA allow for better visualization of extraluminal masses than conventional angiography. Dilated Pulmonary Vein Pulmonary varix refers to localized dilatation of a PV and is usually asymptomatic. It often presents incidentally on chest radiography as a mass, although hemoptysis has also been reported as a presenting symptom. It most commonly occurs in the distal portion of the PV as it joins the left atrium. It can be associated with mitral stenosis or regurgitation and pulmonary venous hypertension. The treatment is usually aimed at correcting the underlying mitral valve dysfunction and pulmonary venous pressure, and direct intervention of the pulmonary varix is usually not required. Narrowing of Pulmonary Vein PV stenosis is a rare condition. The congenital form is usually detected in childhood and can be associated with congenital heart disease. In adults, PV stenosis is often caused by radiofrequency ablation procedures around the PVs performed as treatment for atrial fibrillation. More commonly, PV narrowing is due to external compression by adjacent neoplasm or lymphadenopathy. Mediastinal fibrosis can also cause PV narrowing. Intravascular Filling Defects Filling Defects in Pulmonary Arteries Acute pulmonary embolism, the most common cause of filling defects in the PA, typical results in central filling defect that distends the involved PA branch. Other associated findings may occasionally develop, such as distention of the main PA and right heart related to elevated PA and right heart pressure, and subpleural wedge-shaped opacity due to pulmonary infarct. A small percentage of acute pulmonary emboli fail to resolve and result in chronic PA thromboembolism and pulmonary hypertension. Chronic thromboemboli tend to present as eccentric, linear, or web-like filling defects, and the involved vessels tend to be attenuated. As the affected patients often come to medical attention because of signs and symptoms of pulmonary hypertension, dilated main PA, right atrium, and right ventricle are frequently seen on cross-sectional imaging. Certain primary malignancies, such as renal cell carcinoma and hepatic cellular carcinoma, can grow into the inferior vena cava and extend into the right ventricle. Tumor emboli can result in filling defect(s) in the PA. Rarely, primary PA sarcoma can be the cause of a filling defect. MR is often superior in detection of contrast enhancement within these lesions. FDG PET can also be helpful in demonstrating uptake in hypermetabolic tumors. PA filling defects can also be seen in the setting of Hughes-Stovin syndrome and Behçet disease, where they are thought to represent in situ thrombi instead of emboli. These filling defects most often coexist with PA aneurysm. Filling Defects in Pulmonary Veins Filling defects in the PVs are usually related to PV thrombosis rather than an embolic process. Tumor thrombus related to direct growth of primary or metastatic cancer in the lung into the PV is not uncommon. PV thrombosis can also occur as a rare complication of lung resection or transplantation. Idiopathic PV thrombosis has also been reported. Interlobular septal thickening, ground-glass opacity, and consolidation can be seen in affected lobe of the lung due to pulmonary edema or infarct. Radiographic Findings Although multidetector CT has largely replaced chest radiograph as the imaging modality of choice in the evaluation of pulmonary vasculature, chest radiograph remains the primary and initial imaging study performed when patients present with nonspecific thoracic symptoms. The main PA is seen as a small convexity along the left mediastinal border inferior to the aortic knob on frontal chest radiograph. The right lower lobe PA on frontal chest radiograph should be < 16 mm in diameter. Mild prominence of the main PA can be normal, especially in young women. Dilatation of the main PA and left PA but not the right PA should raise suspicion for pulmonary valve stenosis. Dilatation of a main and bilateral central PA is usually related to pulmonary hypertension. In idiopathic pulmonary hypertension, the peripheral PA branches appear normal or small (pruned), whereas in pulmonary hypertension related to left-to-right shunt and increased pulmonary circulation, the peripheral PA branches are dilated. In the setting of large central pulmonary embolism, the proximal and involved PA may be visibly distended. The underperfusion or oligemia distal to the involved vessel creates the Westermark sign, which is rarely observed. In the setting of pulmonary venous hypertension, cephalization of pulmonary vasculature can be observed. Kerley lines, indistinct vascular markings, and consolidation can be observed when pulmonary edema ensued from elevated pulmonary venous pressure. Abnormalities of the PV are not often directly observed on chest radiograph. However, PV stenosis or thrombosis can manifest with findings of pulmonary edema of the involved portion of the lungs. In pulmonary venoocclusive disease, chest radiograph classically demonstrates dilated main PA related to pulmonary hypertension, and Kerley B lines and diffuse opacity related to pulmonary edema. Pulmonary varix can present as focal nodular or mass-like opacity on chest radiograph. Selected References

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Diagnostic Imaging Cardiovascular 1. Wu CC et al: Pulmonary 64-MDCT angiography with 30 mL of IV contrast material: vascular enhancement and image quality. AJR Am J Roentgenol. 199(6):1247-51, 2012 2. Weininger M et al: Cardiothoracic CT angiography: current contrast medium delivery strategies. AJR Am J Roentgenol. 196(3):W260-72, 2011 3. Grosse C et al: CT findings in diseases associated with pulmonary hypertension: a current review. Radiographics. 30(7):1753-77, 2010 4. Alexander GR et al: Idiopathic pulmonary vein thrombosis: a rare cause of massive hemoptysis. Ann Thorac Surg. 88(1):281-3, 2009 5. Latson LA et al: Congenital and acquired pulmonary vein stenosis. Circulation. 115(1):103-8, 2007 6. Gotway MB et al: Incidentally detected cardiovascular abnormalities on helical CT pulmonary angiography: spectrum of findings. AJR Am J Roentgenol. 176(2):421-7, 2001 P.11:4

Image Gallery

(Left) PA radiograph of a patient with atrial septal defect shows enlargement of central pulmonary arteries and also prominent peripheral pulmonary vasculature due to left-to-right shunt and increased pulmonary circulation. (Right) Axial CECT of the same patient shows dilated pulmonary trunk . Note also that the right upper lobe anterior segmental pulmonary artery is much larger than adjacent bronchus.

(Left) PA radiograph of a patient with pulmonary venoocclusive disease (PVOD) shows a dilated pulmonary trunk and right lower lobe PA measuring 1.9 cm, related to pulmonary hypertension. There are also reticular and hazy opacities in both lungs and small bilateral pleural effusions related to pulmonary edema. (Right) Axial CECT (same patient) confirms dilated pulmonary trunk , diffuse ground-glass opacities, interlobular septal thickening , and 876

Diagnostic Imaging Cardiovascular pleural effusions consistent with PVOD.

(Left) Axial CECT of a patient with lung cancer shows stenosis of the left upper lobe pulmonary artery due to external compression by the lung mass and lymphadenopathy. (Right) Axial CECT in a patient with Hughes-Stovin syndrome shows focal tubular dilatation of the pulmonary artery branches , consistent with pulmonary artery aneurysms. Note also the intraluminal filling defect thought to represent in situ thrombus . P.11:5

(Left) Axial CECT of a patient with hepatic cellular carcinoma with tumor extension into the inferior vena cava (not shown) reveals filling defects in the basal segmental branches of the right lower lobe pulmonary artery due to tumor emboli. (Right) Axial CECT of a patient with metastatic endometrial carcinoma shows a filling defect in the right inferior pulmonary vein , consistent with a tumor thrombus. The patient also has tumor thromboemboli in the pulmonary arteries .

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(Left) Axial CECT shows focal dilatation of the right inferior pulmonary vein near the ostium, consistent with a varix . This is the most common location for pulmonary varices. (Right) Axial CECT shows marked narrowing/occlusion of the right inferior pulmonary vein by a large right lung mass extending into the mediastinum in this patient with metastatic breast cancer.

(Left) Axial cardiac CT of a patient with history of pulmonary vein ablation procedure shows severe stenosis of the left superior pulmonary vein . (Right) Coronal oblique MIP reformation image of the same cardiac CT better delineates the left superior pulmonary vein stenosis . Note that the patient has 3 pulmonary vein ostia on the right, a normal variant.

Pulmonary Arteriovenous Malformation Key Facts Terminology Pulmonary arteriovenous malformation (PAVM) Communication between pulmonary arteries and pulmonary veins Imaging Radiography Nodule with feeding artery(ies) and draining vein(s) CT/MR Sharply defined round or oval nodule with feeding artery(ies) and draining vein(s) Simple: 1 or more feeding arteries from same segmental artery Complex (10%): Multiple feeding arteries from different segmental arteries Contrast echocardiography: Evaluation of cardiac and intrapulmonary shunts 878

Diagnostic Imaging Cardiovascular Nuclear medicine (Tc-99m labeled macroaggregates) Estimation of size of right-to-left shunt Top Differential Diagnoses Metastases Septic emboli Solitary pulmonary nodule Pulmonary artery pseudoaneurysm Pathology Multiple AVMs highly associated with hereditary hemorrhagic telangiectasia Clinical Issues Asymptomatic: Single PAVM < 2 cm in diameter Symptomatic: 40-60 years of age Hemorrhage; paradoxic embolism to CNS Diagnostic Checklist Consider PAVM in lung nodule with associated tubular opacities representing feeding artery and draining vein

(Left) Composite image with posteroanterior and lateral chest radiographs demonstrates a well-defined lobular opacity in the left perihilar region representing the feeding artery and draining vein of a pulmonary arteriovenous malformation (AVM). (Right) Composite image with coronal CT images of the same patient shows the feeding artery and draining vein . This is an example of a simple AVM, which is characterized by 1 or more feeding arteries arising from the same segmental pulmonary artery.

(Left) Composite image with axial CECT images of a patient with hereditary hemorrhagic telangiectasia shows bilateral pulmonary AVMs . (Right) Composite image from digital subtraction angiography demonstrates a simple AVM in the left lower lobe (left) and the presence of coils and absence of AVM and draining vein enhancement 879

Diagnostic Imaging Cardiovascular following coil embolotherapy (right). P.11:7

TERMINOLOGY Abbreviations Pulmonary arteriovenous malformation (PAVM) Definitions Abnormal direct communication between pulmonary arteries and pulmonary veins; direct right-to-left shunt Congenital: Hereditary hemorrhagic telangiectasia (HHT) or Osler-Weber-Rendu syndrome Acquired: Hepatopulmonary syndrome, systemic diseases, venous anomalies, following palliation of complex cyanotic congenital heart disease IMAGING General Features Best diagnostic clue Nodule(s) with feeding artery(ies) and draining vein(s) Location Peripheral lower lobes (50-70%): Medial 1/3 of lung Size Variable: 1-5 cm in diameter Radiographic Findings Radiography Sensitivity for PAVMs: 50-70% Round, oval, or lobulated well-defined nodule with feeding artery(ies) and draining vein(s) Consolidation-like lesions in diffuse PAVM CT Findings Sharply defined round or oval nodule with feeding artery(ies) and draining vein(s) Simple: 1 or more feeding arteries from same segmental artery Complex (10%): Multiple feeding arteries from different segmental arteries Diffuse PAVM (5% of complex PAVMs): Innumerable feeders, frequently lobar MR Findings MRA: Similar to CT for detection Echocardiographic Findings Contrast echocardiography: Evaluation of cardiac and intrapulmonary shunts Nuclear Medicine Findings Tc-99m MAA: Right-to-left shunt size estimate Imaging Recommendations Best imaging tool Multidetector CT with MIP images Protocol advice Screen for PAVMs with CT every 3-5 years Low-dose (30 mAs) unenhanced CT Review with thin-slab MIP (5 mm) Pulmonary angiography for treatment, not for diagnosis DIFFERENTIAL DIAGNOSIS Metastases History of malignancy, usually multiple Septic Emboli Rapid growth, cavitation frequent Blood or central line culture Solitary Pulmonary Nodule Most commonly lung cancer, granuloma, hamartoma Pulmonary Artery Pseudoaneurysm Complication related to pulmonary artery catheter, trauma, or bacterial endocarditis PATHOLOGY General Features Genetics HHT: Autosomal dominant disorder Mutations in ENG & ALK1 on chromosome 9 (75%) 880

Diagnostic Imaging Cardiovascular Gross Pathologic & Surgical Features Draining veins usually larger than feeding arteries CLINICAL ISSUES Presentation Most common signs/symptoms Asymptomatic: Single PAVM < 2 cm in diameter Symptomatic: 40-60 years of age Hemorrhage: Hemoptysis (10%), epistaxis from nasal telangiectasia in 90% of HHT CNS complications (40%): Paradoxical embolism and cerebral abscess Other signs/symptoms Desaturation, exercise intolerance, cyanosis, and clubbing with large PAVMs Demographics Age 10% are diagnosed in infancy or childhood Gender M:F = 1:2 Natural History & Prognosis Growth postulated in puberty and pregnancy Treatment Coil embolotherapy Recanalization in up to 20% Long-term imaging follow-up post therapy DIAGNOSTIC CHECKLIST Consider Consider PAVM in lung nodule with associated tubular opacities representing feeding artery and draining vein Diagnosis Blood test for identification of mutation (80% of patients) Genetic screening Screening of at-risk patients with contrast echocardiography SELECTED REFERENCES 1. Trerotola SO et al: PAVM embolization: an update. AJR Am J Roentgenol. 195(4):837-45, 2010

Pulmonary Artery Pseudoaneurysm Key Facts Terminology Pulmonary artery pseudoaneurysm (PAP) Imaging Radiography Focal consolidation Nodule or mass CT Enhancing nodule or mass adjacent to or arising from pulmonary artery branch Ground-glass halo MDCT with pulmonary angiography protocol is optimal for detection of PAP Top Differential Diagnoses Pulmonary artery aneurysm Pulmonary arteriovenous malformation Pathology Etiology Iatrogenic: Pulmonary artery catheter, surgery, lung biopsy Trauma Infection: TB, bacterial or fungal infection Clinical Issues Signs and symptoms: Hemoptysis, chest pain, incidental imaging finding Mortality rate: Up to 50% Treatment Embolization, stent graft Surgical ligation of vessel or resection of involved portion of lung Reported cases of regression after treatment of infection or neoplasm 881

Diagnostic Imaging Cardiovascular

(Left) AP chest radiograph of a patient with hemoptysis shows a pulmonary artery catheter tip to be beyond the right interlobar pulmonary artery in the right middle or lower lobe pulmonary artery. (Right) Coronal reformat CECT in the same patient shows an enhancing spheric opacity immediately adjacent or arising from the pulmonary artery in the right middle lobe, consistent with a pseudoaneurysm.

(Left) Coronal reformat CECT in the same patient shows a ground-glass halo surrounding the pseudoaneurysm consistent with perilesional parenchymal hemorrhage. (Right) Oblique selective catheter angiography of a segmental middle lobe pulmonary artery shows a focal well-defined round collection of contrast , consistent with a traumatic pseudoaneurysm. P.11:9

TERMINOLOGY Abbreviations Pulmonary artery pseudoaneurysm (PAP) IMAGING Radiographic Findings Focal consolidation Nodule or mass Blunting of costophrenic angle (hemothorax) CT Findings Enhancing nodule or mass adjacent to or arising from pulmonary artery branch Ground-glass halo Related to hemorrhage 882

Diagnostic Imaging Cardiovascular Consolidation Thrombus within dilated pulmonary artery Imaging Recommendations Best imaging tool MDCT with pulmonary angiography protocol Helps identify source of bleeding in patients with hemoptysis Provides road map for endovascular interventions Angiographic Findings Focal saccular outpouching arising from pulmonary artery branches Reversal of flow in pulmonary artery branches on bronchial arterial angiograms Systemic to pulmonary arterial shunting May be seen in patients with chronic inflammatory lung disease Embolization of both bronchial and pulmonary artery branches may be necessary to control hemoptysis DIFFERENTIAL DIAGNOSIS Pulmonary Artery Aneurysm Difficult to distinguish from PAP based on imaging Fusiform dilatation of pulmonary artery is more suggestive of aneurysm Pulmonary Arteriovenous Malformation Enhancing nodular nidus on CT Identification of one or more draining veins are key to the diagnosis Feeding pulmonary artery may be enlarged In contrast, pulmonary artery proximal to PAP is usually of normal size Hypervascular Neoplasm Carcinoid tumor or metastasis from renal cell carcinoma, thyroid cancer, melanoma, etc. Enhancing nodule &/or mass ± ground-glass halo due to perilesional hemorrhage PATHOLOGY General Features Etiology Iatrogenic Pulmonary artery catheter causing perforation Incidence ˜ 0.2% Risk factors: Pulmonary hypertension, age > 60 years, anticoagulation Surgery Biopsy Trauma Penetrating Blunt Infection Bacterial abscesses, septic emboli Staphylococcus aureus Pseudomonas Tuberculosis (TB) Rasmussen aneurysms: 4% of patients with chronic pulmonary TB Often associated with cavitary disease Progressive destruction and replacement of elastic fibers of pulmonary artery by granulation tissue Aspergillosis, mucormycosis Mycetoma complicating chronic TB or sarcoidosis Neoplasm Primary lung cancer Metastasis: Sarcoma CLINICAL ISSUES Presentation Most common signs/symptoms Hemoptysis Incidental imaging finding Other signs/symptoms Chest pain 883

Diagnostic Imaging Cardiovascular Dyspnea Demographics Gender M>F Up to 11% of patients undergoing bronchial angiography for massive hemoptysis Natural History & Prognosis If untreated, can enlarge and rupture, leading to hemorrhage and death Mortality rate: Up to 50% Treatment Embolization of feeding vessel or of pseudoaneurysm itself Coils Particles Endovascular stent graft Surgery Ligation of involved pulmonary artery Wedge resection or lobectomy Watchful waiting Reported cases of regression after treatment of infection or neoplasm SELECTED REFERENCES 1. Lafita V et al: Pulmonary artery pseudoaneurysm: etiology, presentation, diagnosis, and treatment. Semin Intervent Radiol. 24(1):119-23, 2007 2. Sbano H et al: Peripheral pulmonary artery pseudoaneurysms and massive hemoptysis. AJR Am J Roentgenol. 184(4):1253-9, 2005

Pulmonary Artery Aneurysm Key Facts Terminology Pulmonary artery aneurysm (PAA) Focal dilatation of pulmonary artery involving all 3 layers of arterial wall Imaging Chest radiography Round perihilar opacity Hilar enlargement Nonspecific pulmonary nodule or consolidation CT Focal, usually fusiform, dilatation of pulmonary artery Aneurysmal segment is usually isodense or enhances to same degree as adjacent nondilated pulmonary artery segment Adjacent ground-glass opacity or consolidation due to hemorrhage Top Differential Diagnoses Pulmonary artery pseudoaneurysm Pulmonary arteriovenous malformation Pathology Etiologies Rarely idiopathic Primary or secondary pulmonary hypertension Pulmonary valve stenosis Vasculitis: Behçet disease and Hughes-Stovin syndrome Clinical Issues Presentation: Hemoptysis, dyspnea, chest pain Treatment Endovascular intervention: Embolization, stent-graft Surgical resection Immunosuppression for Behçet disease and Hughes-Stovin syndrome

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(Left) Coronal reformat image in a 31-year-old Middle Eastern man who presented with hemoptysis shows mild fusiform dilatation , consistent with aneurysm, of a segmental pulmonary artery branch in the left lower lobe. Note the peripheral thrombus within the aneurysm. (Right) Axial CECT also demonstrates a filling defect within the right ventricle, consistent with a thrombus, which can be seen in patients with Behçet disease.

(Left) Axial CECT of the same patient shows aneurysm of a right middle lobe segmental pulmonary artery with mild adjacent ground-glass opacity, which likely represents hemorrhage. Patients with Behçet disease often have multiple bilateral pulmonary artery aneurysms. (Right) Axial CECT shows right lower lobe subpleural wedge-shaped opacity consistent with pulmonary infarct , thought to be sequelae of pulmonary thrombosis/embolism in patients with Behçet disease. P.11:11

TERMINOLOGY Abbreviations Pulmonary artery aneurysm (PAA) Definitions Dilatation of pulmonary artery (PA) involving all 3 layers of arterial wall IMAGING General Features Best diagnostic clue Dilatation of PA Location Main, hilar, lobar, segmental, and subsegmental PAs can all be involved 885

Diagnostic Imaging Cardiovascular Peripheral PAA is less common Radiographic Findings Radiography Central (main or lobar PAA) enlargement Round perihilar opacity Hilar enlargement Lobulated contour of PA Peripheral PAA (segmental or subsegmental PA) Nonspecific pulmonary nodule(s) Consolidation (hemorrhage) evolves into nodule or mass CT Findings Focal dilatation of PA Usually fusiform in shape but can be saccular Aneurysmal segment are usually isodense or enhance to same degree as adjacent nondilated PA segment Aneurysm may be partially thrombosed Peripheral segmental or subsegmental PAA is sometimes subtle and difficult to detect Sometimes better visualized in lung window Adjacent ground-glass opacity or consolidation Hemorrhage due to rupture or leakage of PAA Findings related to PA hypertension Idiopathic Dilated central PA and pruning of distal PA Dilated right heart chambers Right to left shunt Atrial or ventricular septal defect Patent ductus arteriosus Evidence of congenital heart disease repair Chronic PA thromboembolic disease Linear, web-like, or peripheral filling defects in PA Attenuation of vessels distal to filling defects Mosaic perfusion of lungs Pulmonary disease Emphysema Interstitial fibrosis Peripheral reticular opacities Traction bronchiectasis Mural calcification Atherosclerosis due to chronic severe pulmonary hypertension Calcified intramural thrombus Pulmonary valve stenosis Enlarged main and left PA from effect of jet across stenotic valve Left upper lobe arteries larger than mirror-image arteries in right upper lobe (due to increased flow) Calcified or thickened pulmonary valve Behçet disease Perihilar or parenchymal nodular opacities: PAAs (often multiple, bilateral) ± vascular wall thickening and enhancement PA filling defect More often in situ thrombi than emboli Intracardiac filling defect (thrombus) Particularly in right ventricle Pulmonary infarct Subpleural wedge-shaped opacity, cavitary lesion Pulmonary hemorrhage Consolidation Ground-glass opacity Pulmonary artery stenoses/occlusion Deep venous thrombosis (vena cava, innominate, and subclavian veins) Pleural effusion 886

Diagnostic Imaging Cardiovascular Hughes-Stovin syndrome Single or multiple PAA Systemic arterial aneurysm, including bronchial artery aneurysm Thrombosis of vena cava, jugular vein, or cardiac chambers MR Findings Similar to CT but less sensitive Illustrates vascular wall thickening to better advantage in setting of vasculitis Better for characterizing underlying pulmonary valvular stenosis or left-to-right shunt Angiographic Findings Depicts focal dilation of PA In Behçet disease, vascular puncture may lead to aneurysm formation; therefore, CTA would be more preferable for diagnosis Imaging Recommendations Best imaging tool CTA with multiplanar reformations is most sensitive, particularly for small peripheral PAA DIFFERENTIAL DIAGNOSIS Pulmonary Artery Pseudoaneurysm Does not involve all 3 layers of vessel wall Saccular instead of fusiform shape More often related to iatrogenic or noniatrogenic trauma or infection More likely to rupture More often peripheral (involving smaller PA branches) Pulmonary Arteriovenous Malformation Feeding PA appears dilated Identification of draining vein is key to diagnosis PATHOLOGY General Features Etiology Idiopathic: Very rare PA hypertension P.11:12

Primary Secondary Left-to-right shunt Chronic PA thromboembolic disease Pulmonary disease Pulmonary valve stenosis Idiopathic vasculitis Behçet disease Hughes-Stovin syndrome Genetics Behçet disease: HLA-B51 Gross Pathologic & Surgical Features Behçet disease Inflammation of vasa vasorum → ischemia/weakening of vessel wall → true and false aneurysms Adventitial fibrosis and thrombus formation can occur Hughes-Stovin syndrome Diffuse dilatation and partial occlusion of PAA Microscopic Features Behçet disease Neutrophilic infiltration Endothelial cell swelling Fibrinoid necrosis Hughes-Stovin syndrome Perivascular lymphomonocytic infiltration Diffuse proliferative sclerosis Tunica media of affected vessels filled with lymphocytes, plasma cells, and foam cells 887

Diagnostic Imaging Cardiovascular CLINICAL ISSUES Presentation Most common signs/symptoms Usually asymptomatic Hemoptysis Dyspnea Other signs/symptoms Chest pain Behçet disease Behçet triad: Oral ulcerations, genital ulceration, uveitis Skin findings: Folliculitis, erythema nodosum Venous thrombophlebitis Fever Hughes-Stovin syndrome Fever Seizures, diplopia, papilledema Cerebral venous sinus thrombosis leading to elevated intracranial pressure Demographics Age Behçet disease Mean: 30.1 years (range: 10-59 years) Hugh-Stovin syndrome Young adult Gender Behçet disease Male predilection Hugh-Stovin syndrome Strong male predilection (80-90% of cases) Ethnicity Behcet disease Ancient Silk Road: Far East, Middle East, Eastern Mediterranean Epidemiology Behçet disease Turkey: 4 cases per 1,000 people Asian countries: 2-30 cases per 100,000 people USA: < 1 case per 100,000 people Hughes-Stovin syndrome < 40 reported cases in English language literature Natural History & Prognosis Peripheral aneurysms rupture in 60% cases Behçet disease 1-year survival rate: ˜ 50% for patients with PAA Better survival rate in more recent reports due to better treatment PAA can be present at time of diagnosis or develop years after initial presentation Hughes-Stovin syndrome Aneurysm rupture is main cause of death Small aneurysm can stabilize or regress with immunosuppression Treatment Peripheral PAA Intravascular coil or balloon embolization Surgical resection of involved lung segment or lobe if limited disease Main PAA Surgical repair Excision of aneurysm and prosthetic patch replacement Pneumonectomy High morbidity and mortality Behçet disease and Hughes-Stovin syndrome Corticosteroids, cyclophosphamide, or other immunosuppressants

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Diagnostic Imaging Cardiovascular Anticoagulation is generally not recommended but occasionally used to treat intracardiac thrombi or massive pulmonary emboli DIAGNOSTIC CHECKLIST Consider Possible underlying cause Idiopathic Pulmonary hypertension Pulmonary valvular stenosis Vasculitis SELECTED REFERENCES 1. Calamia KT et al: Major vessel involvement in Behçet's disease: an update. Curr Opin Rheumatol. 23(1):24-31, 2011 2. Khalid U et al: Hughes-Stovin syndrome. Orphanet J Rare Dis. 6:15, 2011 3. Nguyen ET et al: Pulmonary artery aneurysms and pseudoaneurysms in adults: findings at CT and radiography. AJR Am J Roentgenol. 188(2):W126-34, 2007 4. Castañer E et al: Congenital and acquired pulmonary artery anomalies in the adult: radiologic overview. Radiographics. 26(2):349-71, 2006 5. Uzun O et al: Pulmonary vasculitis in behcet disease: a cumulative analysis. Chest. 127(6):2243-53, 2005 P.11:13

Image Gallery

(Left) Coronal reformat CECT of a patient with Hughes-Stovin syndrome shows large fusiform aneurysm of a right pulmonary artery branch with delayed contrast enhancement and mural thrombus . (Right) Axial CECT shows that the patient also has a smaller pulmonary artery aneurysm on the left in addition to the larger aneurysm on the right . Note the relatively decreased contrast opacification in the larger aneurysm. (Courtesy B. W. Carter, MD.)

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(Left) Axial CECT of a different patient with Hughes-Stovin syndrome shows a pulmonary artery aneurysm in a subsegmental pulmonary artery of the left lower lobe . Note the significant size difference compared to all other subsegmental arteries at that level. (Right) Coronal maximum-intensity projection (MIP) reformat CECT in the same patient shows the fusiform nature of the left lower lobe pulmonary artery aneurysm and its relationship to the distal vessel . (Courtesy J. H. Chung, MD.)

(Left) PA radiograph shows left hilar prominence suggestive of dilatation of the main and left pulmonary arteries. The right interlobar pulmonary artery appears normal in caliber. (Right) Axial CECT confirms dilatation of the pulmonary trunk and left main pulmonary artery without involvement of the right main pulmonary artery, consistent with pulmonary valve stenosis, later confirmed by echocardiogram.

Acute Pulmonary Embolism Key Facts Terminology Pulmonary arterial blockage caused by clots traveling to pulmonary arteries from other parts of the body Imaging Chest radiography Westermark sign: Focal radiolucency (oligemia) distal to obstructed pulmonary artery Hampton hump (pulmonary infarct): Peripheral wedge-shaped opacity with apex pointing toward hilum Pleural effusion Ventilation/perfusion scan Mismatched perfusion defects Pulmonary CTA 890

Diagnostic Imaging Cardiovascular Imaging modality of choice Filling defect(s) in pulmonary arterial system Distension of involved vessel Ratio of right ventricular to left ventricular diameter > 1 suggests right heart strain; poor prognosis Top Differential Diagnoses Tumor thrombus/embolus Primary pulmonary artery sarcoma Flow artifact Pathology 70% of patients with pulmonary emboli have lower extremities deep vein thrombosis Clinical Issues Symptoms: Dyspnea, chest pain, tachycardia Risk factors: Immobilization, pregnancy, malignancy Treatments Anticoagulation Thrombolysis Embolectomy

(Left) Axial pulmonary CTA shows extensive right interlobar and bilateral lobar pulmonary artery filling defects with associated distention of involved pulmonary artery segments, consistent with acute pulmonary embolism. (Right) Axial CTA of the same patient in lung window shows a left lower lobe subpleural wedge-shaped opacity, consistent with pulmonary infarct. Note also the small left pleural effusion. The latter is a common finding in patients with pulmonary emboli.

(Left) Axial CTA of the same patient shows dilated right atrium and right ventricle, consistent with right heart strain. 891

Diagnostic Imaging Cardiovascular Right ventricular to left ventricular diameter ratio > 1 is associated with higher mortality. Note that the interventricular septum is bowed toward the left ventricle. (Right) Coronal reformat CECT of a patient with colon cancer shows an incidental pulmonary embolus in a right lower lobe segmental pulmonary artery branch . Incidental pulmonary emboli are found in ˜ 4% of oncology patients. P.11:15

TERMINOLOGY Definitions Pulmonary artery (PA) blockage caused by clots that travel to PA from other parts of the body IMAGING General Features Best diagnostic clue Central filling defect within opacified PAs on CTA, MRA, or conventional angiography Peripheral wedge-shaped consolidation Location Commonly bilateral May involve any portion of pulmonary vascular bed Size May be of any size Large emboli lodge proximally and may cause serious symptoms Small emboli are asymptomatic or may cause pulmonary infarct Morphology Sharp interface with intravascular contrast material Saddle embolus: Large embolus that straddles main PA bifurcation Radiographic Findings Radiography Poor sensitivity and specificity Vascular alteration Enlargement of central PA with abrupt tapering (“knuckle” sign) or enlarged right interlobar PA (Palla's sign) Enlargement due to vascular distension by clot and increased proximal pulmonary pressure Westermark sign: Focal lucency (oligemia) distal to obstructed PA Atelectasis: Secondary to decreased ventilation or depletion of surfactant Pleural effusion: ˜ 1/2 of patients with pulmonary embolus (PE) Sometimes only radiographic finding Pulmonary infarct < 15% of embolic events result in infarction Hampton hump: Peripheral wedge-shaped opacity with apex pointing toward hilum Usually in lower lung zones Can take months to resolve and leave linear scars (Fleischner lines) or pleural thickening Infarcts “melt” (maintain shape, gradually shrink); pneumonia and edema “fade” away (decrease density) Rarely cavitates, unless infection or sepsis is present CT Findings NECT Emboli hyper- or hypoattenuating relative to adjacent unenhanced blood depending on chronicity of clot and patient's hematocrit level CECT CT pulmonary angiography (CTPA) is examination of choice Highly sensitive and specific High interobserver agreement Directly visualizes clot (filling defect) in PA and helps to assess overall clot burden Occlusion of entire lumen and enlargement of involved artery Partial filling defect surrounded by contrast “Railway track” sign (viewed in long axis) “Polo mint” sign (viewed in short axis) Other findings Dilated main PA is suggestive of PA hypertension 892

Diagnostic Imaging Cardiovascular Right heart strain Ratio of right ventricular to left ventricular diameter > 1; good predictor of mortality Straightening or bowing of interventricular septum toward left ventricle Venous thrombus in vena cava or internal jugular or subclavian veins Thrombus or embolus in right ventricle Pulmonary infarct Peripheral wedge-shaped opacity Points toward hilum with broad pleural base Often in lower lobes Negative CTPA outcomes are good (< 1% subsequent embolic rate) Negative CTPA rules out PE Pitfalls Poor bolus, flow-related artifacts Hilar, bronchopulmonary lymph nodes Respiratory motion artifacts Delayed CT venography of thighs can be performed for deep vein thrombosis (DVT) evaluation Dual-energy CTPA Allows visualization of PE as in conventional CTPA Provides blood flow images that show peripheral, wedge-shaped perfusion defects in lobar or segmental distribution Improves detection for small peripheral PEs MR Findings MRA Prospective Investigation of PE Diagnosis III (PIOPED III): Gadolinium-enhanced MRA Technically inadequate study in 25% of patients Sensitivity 78%, specificity 99% in technically adequate studies Considered only in patients with contraindications to standard tests in experienced centers Filling defect(s) in PA system similar to CTPA MR cine Paradoxical systolic motion of interventricular septum if right ventricular pressure is elevated Ultrasonographic Findings Doppler ultrasound with compression is helpful when lower or upper extremity DVT is suspected Angiographic Findings Now primarily performed for catheter-directed thrombectomy or thrombolysis and for right heart and PA pressure measurements Nuclear Medicine Findings Ventilation/perfusion (V/Q) scan findings Abnormal perfusion and normal ventilation result in “mismatched” perfusion defect in PE High sensitivity but poor specificity P.11:16

Normal perfusion scan excludes embolus Matched defect can occur with pulmonary infarct Other causes of V/Q mismatch include vasculitis, external compression of PA, pulmonary hypertension, and fibrosing mediastinitis Imaging Recommendations Best imaging tool CTPA is study of choice for suspected PE V/Q scan for patients with iodinated contrast allergy or renal failure In pregnant patients without leg symptoms V/Q scan is preferred if normal chest radiograph CTPA is preferred if abnormal chest radiograph Protocol advice Bolus tracking, where scan acquisition is triggered automatically by detection of preset attenuation in region of interest (usually main PA or right ventricle), allows optimal contrast opacification Thin collimation (1-1.5 mm) following 80-100 mL intravenous contrast at rate of 3-4 mL/s with coronal/sagittal reformats DIFFERENTIAL DIAGNOSIS 893

Diagnostic Imaging Cardiovascular Tumor Thrombus/Embolus Primary malignancy is usually known Can demonstrate enhancement PE usually does not enhance Dilated, beaded PAs Primary Pulmonary Artery Sarcoma Irregular, lobulated, and wall adherent Enhancement of mass indicates vascularity Persistent despite anticoagulation Laminar Flow Artifact Relatively low-density linear filling defect; ill-defined margins; more common at vessel bifurcations PE is well-defined low-density filling defect Commonly seen in patients with congenital heart disease having shunts/conduits (e.g., Fontan, Glenn) Obtain arterial- and delayed-phase scans or utilize simultaneous foot and antecubital injections MR or MRA is attractive alternative approach PATHOLOGY General Features Etiology 70% of patients with PE have lower extremities DVT Gross Pathologic & Surgical Features Hemodynamic effects: > 50% vascular bed reduction causes pulmonary hypertension &/or right heart failure Microscopic Features Pulmonary infarct: Ischemic necrosis of alveolar wall, bronchi, and vessels + focal hemorrhage CLINICAL ISSUES Presentation Most common signs/symptoms Dyspnea Chest pain Tachycardia Other signs/symptoms Cough Hypotension, syncope Hemoptysis Can be asymptomatic Clinical profile Decision support tool, such as Wells criteria, is helpful to determinate pretest likelihood of PE Negative high-sensitivity D-dimer test and absence of high pretest probability effectively exclude PE Demographics Age All age groups; increased incidence in older patients Epidemiology Risk factors Immobilization Hospitalization Long distance air travel Surgery (particularly orthopedic or pelvic) Pregnancy or contraceptive medications Malignancy (4% with incidental PE) Obesity Congenital hypercoagulable state Protein C or S deficiency Factor V Leiden mutation Prothrombin 20210A mutation Indwelling central venous catheters Trauma Natural History & Prognosis 15-30% mortality without appropriate anticoagulation Unknown outcomes for untreated subsegmental PE Treatment 894

Diagnostic Imaging Cardiovascular Anticoagulation is mainstay of treatment Hemorrhagic complications in 2-15% Thrombolysis for severely symptomatic patients May be delivered systemically via intravenous administration Direct catheter delivery into clot Contraindications: Intracranial disease (stroke, tumor, head trauma), active bleeding, aortic dissection Inferior vena cava filter if contraindications to drug therapy Catheter or surgical embolectomy in selected high-risk patients SELECTED REFERENCES 1. Bettmann MA et al: ACR Appropriateness Criteria® acute chest pain—suspected pulmonary embolism. J Thorac Imaging. 27(2):W28-31, 2012 2. Leung AN et al: American Thoracic Society documents: an official American Thoracic Society/Society of Thoracic Radiology Clinical Practice Guideline—Evaluation of Suspected Pulmonary Embolism in Pregnancy. Radiology. 262(2):635-46, 2012 3. Douma RA et al: Acute pulmonary embolism. Part 1: epidemiology and diagnosis. Nat Rev Cardiol. 7(10):585-96, 2010 4. Stein PD et al: Gadolinium-enhanced magnetic resonance angiography for pulmonary embolism: a multicenter prospective study (PIOPED III). Ann Intern Med. 152(7):434-43, W142-3, 2010 P.11:17

Image Gallery

(Left) Axial NECT shows focal hyperdensity within the lumen of the right interlobar pulmonary artery . (Right) Axial CTA of the same patient confirms focal filling defect in the right interlobar pulmonary artery, consistent with a pulmonary embolus. A pulmonary embolus can occasionally appear hyper- or hypodense on noncontrast CT, depending on the chronicity of clot and patient's hematocrit, although most will be inapparent.

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(Left) Axial pulmonary CTA shows a large filling defect straddling the bifurcation of the main pulmonary artery, consistent with a saddle embolus. The main pulmonary artery is dilated, suggestive of elevated pulmonary arterial pressure. (Right) Coronal gadolinium-enhanced MRA in the pulmonary arterial phase shows bilateral endoluminal signal voids (black) surrounded by gadolinium-enhanced blood pool, consistent with filling defects due to bilateral pulmonary emboli.

(Left) Perfusion portion of a V/Q scan after intravenous injection of technetium macroaggregated albumin (Tc-99m MAA) in different projections shows multiple bilateral segmental and subsegmental perfusion defects . (Right) Ventilation scan (posterior view) in the same patient during wash-in and wash-out show no matching ventilation defects. The mismatched perfusion defects are highly suggestive of pulmonary embolism.

Chronic Pulmonary Embolism Key Facts Terminology Gradual formation of organized thromboemboli following acute pulmonary embolism with resultant pulmonary vascular obstruction/obliteration Imaging CT Eccentric filling defect and luminal narrowing Linear, web-like filling defect Enlarged central pulmonary artery Decreased diameter of involved pulmonary artery branch Dilated right heart chambers 896

Diagnostic Imaging Cardiovascular Dilated bronchial artery collateral Mosaic attenuation of pulmonary parenchyma Pulmonary angiography Complete vessel cut-off with convex margin of contrast column: “Pouch” deformity V/Q scan Mismatched perfusion defects Top Differential Diagnoses Pulmonary arterial hypertension Large-vessel arteritis (Takayasu arteritis) Clinical Issues Clinical presentation Progressive dyspnea; exercise intolerance Up to 50% of patients have no history of documented pulmonary embolism or deep vein thrombosis 3-4% incidence of symptomatic chronic thromboembolic pulmonary hypertension after acute pulmonary embolism Treatment Lifetime anticoagulation Medication to target pulmonary arterial hypertension Surgical pulmonary thromboendarterectomy

(Left) Axial pulmonary CTA shows an eccentric filling defect in the right interlobar pulmonary artery, consistent with a chronic thromboembolus. Note that the thrombus is murally adherent and not surrounded by contrast material. The main pulmonary artery is dilated, consistent with pulmonary arterial hypertension. (Right) Coronal reformat CTA shows a linear filling defect within a segmental branch in the left lower lobe. As in this case, chronic pulmonary emboli may be subtle on CT.

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(Left) Axial CTA of the same patient shows dilatation of the right atrium and right ventricle, consistent with elevated right heart pressure. Note the straightening of the interventricular septum . Also note that the pulmonary arterial branches in the right lower lobe are smaller in caliber than those on the left. (Right) Axial CTA shows mosaic perfusion of the lung parenchyma. Hypoattenuating areas correspond to areas of hypoperfusion. P.11:19

TERMINOLOGY Abbreviations Pulmonary embolism (PE) Synonyms Chronic pulmonary arterial thromboembolic disease Definitions Gradual formation of organized thromboemboli following acute PE with resultant pulmonary vascular obstruction/obliteration IMAGING General Features Best diagnostic clue Eccentric, wall-adherent, low-density filling defect; dilated pulmonary artery(ies) Location Pulmonary arteries, commonly bilateral Size Usually smaller than in acute PE Radiographic Findings Radiography Findings of pulmonary hypertension Pulmonary artery enlargement Right heart enlargement Subpleural opacities from prior pulmonary infarcts Attenuation of lobar or segmental pulmonary artery branch CT Findings HRCT Mosaic perfusion of lung Heterogeneous attenuation of pulmonary parenchyma from variable perfusion Darker areas = decreased perfusion due to vascular obstruction or distal arteriopathy Vessels in darker area are often attenuated Brighter or higher attenuation areas = normal or increased perfusion Darker areas not accentuated by expiration, unlike air-trapping Subpleural linear opacities = scar from prior pulmonary infarcts Mild segmental or subsegmental bronchiectasis CTA 898

Diagnostic Imaging Cardiovascular Pulmonary CTA allows direct visualization of chronic embolus/organized thrombus Eccentric filling defect and luminal narrowing Smooth or nodular vascular wall thickening Linear, web-like filling defect Abrupt stenosis or occlusion of vessel Chronic PE: Convex margin of contrast column Acute PE: Concave margin of contrast column of occluded vessel (clot has convex margin) “Pruning” of peripheral arteries distal to chronic PE Pulmonary arteries are smaller than adjacent bronchi Pulmonary arteries are smaller than contralateral equivalent branches Rarely eccentric wall-adherent calcification Enlarged main pulmonary artery Pulmonary artery to ascending aorta diameter ratio > 1 Main pulmonary artery diameter > 2.9 cm Cardiac findings Right ventricular enlargement: Right to left ventricular diameter ratio > 1 at midventricular level Straight or left-bowing interventricular septum D-shaped left ventricular cavity on short-axis view Muscular hypertrophy of right ventricle Tricuspid regurgitation Dilatation and reflux of contrast into inferior vena cava and hepatic veins Systemic collateral flow to lung Enlarged bronchial, intercostal, or internal mammary arteries Rare in primary pulmonary hypertension Enlarged bronchial arteries are more common with central disease Exclude alternative causes of pulmonary hypertension Congenital cardiovascular disease: Atrial septal defect, patent ductus arteriosus, anomalous pulmonary venous drainage Pulmonary parenchymal disease: Emphysema, interstitial fibrosis Other pulmonary vascular diseases: Venoocclusive disease, capillary hemangiomatosis, vascular occlusions secondary to mediastinal fibrosis or pulmonary artery sarcoma MR Findings MRA Correlates well with CTA to segmental level Cannot reliably detect smaller thrombi Thrombi are seen as eccentric, low-signal defects along arterial wall on SSFP, MRA, and CE GRE sequences Vessel occlusions, intraluminal webs and bands Time-resolved MRA is useful for pulmonary perfusion pattern MR cine Allows qualitative and quantitative assessment of ventricular function Phase-contrast imaging measures flow in systemic and pulmonary vessels Before and after pulmonary thromboendarterectomy Echocardiographic Findings Evidence of pulmonary arterial hypertension Right atrial and ventricular enlargement/dysfunction Tricuspid regurgitation Excludes cardiac causes of pulmonary hypertension (e.g., patent foramen ovale, septal defect) Angiographic Findings Complete vessel cut-off Convex margin of contrast column: “Pouch” deformity Narrowing or web-like filling defect of pulmonary artery Allows measurement of right ventricular and pulmonary artery hemodynamics Nuclear Medicine Findings PET May aid in differentiating pulmonary arteritis (Takayasu) and chronic PE P.11:20

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V/Q scan Normal V/Q scan rules out chronic PE Multiple mismatched segmental or larger defects Magnitude of perfusion defects often understates actual degree of obstruction Imaging Recommendations Best imaging tool CTA is preferred imaging modality for suspected chronic thromboembolic pulmonary hypertension (CTEPH) Protocol advice Use bolus-tracking software with region of interest over main pulmonary artery to optimally opacify arterial system Thin collimation acquisition allows thin maximum intensity projection and multiplanar reconstruction and improves sensitivity DIFFERENTIAL DIAGNOSIS Pulmonary Artery Sarcoma Usually irregular, lobulated, wall adherent Contrast-enhancement (best on MR) is seen in sarcoma (vascular); not with thrombus (usually avascular) May involve pulmonary valve and extend retrograde into right ventricular infundibulum; does not occur with chronic PE Large-Vessel Vasculitis (Takayasu Arteritis) Mural thickening in pulmonary vasculitis can resemble eccentric thrombus Other vessels such as aorta are involved in vasculitis CT and MR may identify circumferential inflammatory mural thickening MR is better than CT in assessing wall enhancement Differentiates active vs. chronic vasculitis FDG PET shows intense uptake in active disease Idiopathic Pulmonary Hypertension Mosaic perfusion is less common and less prominent in idiopathic pulmonary hypertension Bronchial artery collateral is more common in CTEPH, uncommon in idiopathic pulmonary hypertension PATHOLOGY General Features Etiology Incomplete resorption of pulmonary emboli that organize, become adherent, and incorporate into arterial wall Secondary small-vessel arteriopathy Proximal pulmonary artery occlusion and arteriopathy contribute to elevated pulmonary vascular resistance Associated abnormalities 20% with lupus/anticardiolipin antibodies Risk factors Indwelling catheters, leads Splenectomy Thyroid replacement therapy History of malignancy CLINICAL ISSUES Presentation Most common signs/symptoms Progressive exertional dyspnea Exercise intolerance Other signs/symptoms Exertional chest pain Syncope Palpitation Hemoptysis Demographics Age More common in older patients 900

Diagnostic Imaging Cardiovascular Gender M=F Epidemiology 3-4% incidence of symptomatic CTEPH after acute PE Natural History & Prognosis Up to 50% of patients have no history of documented PE or deep vein thrombosis Extent of vascular obstruction is major determinant of development of pulmonary hypertension Low survival rate without intervention 3-year mortality rate is up to 90% if mean pulmonary artery pressure > 50 mm Hg Treatment Lifetime anticoagulation Medication to target pulmonary arterial hypertension Surgical pulmonary thromboendarterectomy Removal of thromboemboli Operability depends on presence of central (main, lobar, or proximal segmental) disease CT is key for preoperative evaluation Extensive lung parenchymal disease is contraindication for surgery DIAGNOSTIC CHECKLIST Consider Chronic PE in patient with chronic dyspnea, pulmonary arterial hypertension with eccentric or web-like pulmonary artery filling defects, or mosaic perfusion SELECTED REFERENCES 1. Jenkins D et al: State-of-the-art chronic thromboembolic pulmonary hypertension diagnosis and management. Eur Respir Rev. 21(123):32-9, 2012 2. Junqueira FP et al: Pulmonary arterial hypertension: an imaging review comparing MR pulmonary angiography and perfusion with multidetector CT angiography. Br J Radiol. 85(1019):1446-56, 2012 3. Willemink MJ et al: CT evaluation of chronic thromboembolic pulmonary hypertension. Clin Radiol. 67(3):277-85, 2012 4. Cummings KW et al: Multidetector computed tomographic pulmonary angiography: beyond acute pulmonary embolism. Radiol Clin North Am. 48(1):51-65, 2010 5. Coulden R: State-of-the-art imaging techniques in chronic thromboembolic pulmonary hypertension. Proc Am Thorac Soc. 3(7):577-83, 2006 P.11:21

Image Gallery

(Left) AP angiography of right pulmonary artery demonstrates abrupt narrowing of several pulmonary artery branches . Note the occlusion of a vessel with a convex margin of contrast column constituting the “pouch” sign . (Right) Axial CTA of the same patient shows an eccentric linear filling defect . These angiographic and CT findings are consistent with chronic pulmonary emboli.

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(Left) Tc-99m MAA arterial perfusion scan in various projections of the same patient shows multiple bilateral perfusion defects. The ventilation scan was normal. These mismatched defects are consistent with chronic emboli in the setting of progressive dyspnea. (Right) Coronal reformat CTA shows a web-like filling defect with calcification in the left lower lobe pulmonary artery, consistent with a chronic pulmonary embolus.

(Left) Axial CTA shows irregular wall thickening due to mural thrombus in the right lower lobe pulmonary artery , consistent with a chronic pulmonary embolus. (Right) Axial CTA shows dilated main pulmonary artery, consistent with pulmonary arterial hypertension. Note the presence of multiple dilated bronchial artery collaterals , which occur more frequently with central chronic pulmonary emboli. Note the pulsation artefact in the normal ascending aorta.

Pulmonary Sequestration Key Facts Terminology Pulmonary sequestration No normal communication with tracheobronchial tree Systemic blood supply Intralobar sequestration (ILS): ˜ 75% Shares visceral pleura of affected lobe Extralobar sequestration (ELS): ˜ 25% Supernumerary lung tissue covered by pleura, separate from adjacent lung Imaging ILS: Lower lobe lung mass or consolidation Heterogeneous attenuation accentuated by contrast enhancement of solid areas 902

Diagnostic Imaging Cardiovascular Intrinsic air, fluid, and soft tissue components Solid lesions may mimic consolidation ELS: Basilar triangular opacity Homogeneous or heterogeneous soft tissue mass with well-defined borders May exhibit fluid-filled cysts with associated pulmonary airway malformation CTA/MRA: Visualization of systemic vascular supply MR: Lesion characterization Top Differential Diagnoses Pneumonia Lung abscess Lung cancer Postobstructive pneumonia Congenital pulmonary airway malformation Clinical Issues Signs and symptoms of pulmonary infection Treatment ILS: Lobectomy ELS: Surgical excision

(Left) Graphic shows the morphologic features of intralobar sequestration, which typically manifests as a mass-like opacity or consolidation in the inferior left hemithorax. Air, fluid, &/or air-fluid levels may be present. An anomalous systemic aortic branch courses in the pulmonary ligament to supply the lesion. (Right) Posteroanterior radiograph of a patient with recurrent pneumonia shows a mass-like opacity in the right lower lung zone. Note the air-fluid level .

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Diagnostic Imaging Cardiovascular (Left) Axial CECT of the same patient shows a lobulated mass in the right lower lobe. Note the foci of air and air-fluid levels . (Right) Axial CECT of the same patient demonstrates the low attenuation of the majority of the right lower lobe mass, consistent with fluid components. However, scattered foci of enhancement within the mass are consistent with solid components. Note the vessels coursing through the mass. P.11:23

TERMINOLOGY Definitions From Latin “sequestrare” (to be separated) Pulmonary sequestration No normal communication with tracheobronchial tree Systemic blood supply Intralobar sequestration (ILS): ˜ 75% Shares visceral pleura of affected lobe Extralobar sequestration (ELS): ˜ 25% Supernumerary lung tissue covered by pleura, separate from adjacent lung Bronchopulmonary foregut malformation Pulmonary sequestration (ELS or ILS) with foregut communication (esophagus, stomach) (rare) IMAGING General Features Best diagnostic clue ILS: Chronic basilar mass, consolidation, or cystic lesion in patient with recurrent infection ELS: Left lower thoracic soft tissue mass with systemic blood supply in neonate Location ILS: Lower lobes, slightly more common on left (55-64%) Posterior basal segments > medial basal segments ELS: Basilar thorax adjacent to hemidiaphragm Left-sided in 65-90% of cases Typically between hemidiaphragm and lung base Can also be intradiaphragmatic, abdominal, or mediastinal Radiographic Findings ILS Lower lobe lung mass or consolidation Well-defined, lobular, irregular, or ill-defined margins Homogeneous lesion May mimic mass or consolidation Heterogeneous lesion May exhibit cystic spaces with air/air-fluid levels Predominantly cystic lesions may occur Large lesions may produce mass effect on adjacent lung and mediastinum ELS Basilar triangular opacity, well-defined borders Adjacent to posterior medial hemidiaphragm No intrinsic air, air-fluid levels, or air bronchograms Large lesions may produce opaque hemithorax CT Findings ILS Basilar consolidation or mass Irregular borders with adjacent nonsequestered lung; well-defined lobular borders may be present May mimic neoplasm Heterogeneous attenuation accentuated by contrast enhancement of solid areas Intrinsic air, fluid, and soft tissue components Single or multiple intralesional cystic changes May contain air, fluid, &/or air-fluid levels Solid lesions may mimic consolidation May exhibit intralesional branching vessels Surrounding lung may appear hyperlucent or emphysematous May mimic air trapping 904

Diagnostic Imaging Cardiovascular Identification of systemic blood supply ˜ 80% of cases on CECT or CT angiography Systemic artery arising from distal thoracic or upper abdominal aorta Anomalous artery typically 6-7 mm in diameter Multiple systemic arteries in up to 20% of cases Feeding artery often courses within pulmonary ligament Nonvisualization of systemic artery does not exclude diagnosis ELS Homogeneous or heterogeneous soft tissue mass with well-defined borders May exhibit fluid-filled cysts with associated pulmonary airway malformation Visualization of systemic vascular supply Single or multiple feeding vessels MR Findings Lesion characterization Variable signal intensity of cystic components Typically high signal intensity on T2WI Identification of systemic blood supply on MRA Angiographic Findings Angiography is rarely performed Identification of arterial blood supply ILS Thoracic aorta (75%) Abdominal aorta (20%) Intercostal artery (5%) Multiple arteries (16%) ELS Thoracic or abdominal aorta (80%) Other (20%): Splenic, gastric, subclavian, intercostals Multiple arteries (20%) May allow identification of venous drainage ILS 95% have pulmonary venous drainage 5% systemic venous drainage, usually via azygos, hemiazygos, superior vena cava, or intercostal routes Imaging Recommendations Best imaging tool CTA is imaging modality of choice for characterization and identification of systemic blood supply Protocol advice Multiplanar reformatted images and maximum-intensity projection (MIP) images for optimal identification and characterization of vascular supply and venous drainage DIFFERENTIAL DIAGNOSIS Pneumonia Consolidation No systemic blood supply Complete resolution with antibiotics P.11:24

Lung Abscess Mass/mass-like consolidation Intrinsic cavitation No systemic blood supply Slow response to antibiotic treatment May rarely require external drainage Lung Cancer Preferential upper lobe involvement Mass/mass-like consolidation May exhibit cavitation Locally invasive 905

Diagnostic Imaging Cardiovascular No systemic blood supply Postobstructive Pneumonia Endoluminal tumor/obstructing lesion Volume loss Peripheral consolidation No systemic blood supply Congenital Pulmonary Airway Malformation Congenital lung lesion of neonates and infants Microcystic congenital pulmonary airway malformation (solid appearing) may mimic ELS Normal blood supply and venous drainage PATHOLOGY General Features Etiology Controversy regarding etiology Postulated acquired etiology Most lesions were originally described in adults Rare association with other congenital anomalies Normal pulmonary venous drainage Postulated chronic lower lobe pneumonia with loss of pulmonary artery supply/airway communication and acquisition of systemic blood supply from parasitized pulmonary ligament arteries Postulated congenital etiology Increasing reports of ILS in neonates and infants with increased utilization of prenatal ultrasound Reports of coexistent ILS and ELS in same infant Associated abnormalities ELS: Associated congenital anomalies (65%) Bronchogenic cyst Congenital diaphragmatic hernia Gross Pathologic & Surgical Features ILS 98% of cases in lower lobes Left slightly more common than right Intralobar location No normal communication with tracheobronchial tree Thick, fibrous visceral pleura over lesion Cut section Solid &/or cystic components Dense fibrotic consolidated lung Cysts contain blood, pus, or gelatinous material Cystic spaces resemble ectatic bronchi Surrounded by nonsequestered lung Systemic arterial supply and pulmonary venous drainage ELS Ovoid, spherical, or pyramidal soft tissue mass Pleural investment in thoracic lesions Systemic arterial supply and systemic venous drainage May exhibit internal cystic changes Microscopic Features ILS Chronic inflammation, vascular sclerosis, cystic changes, and extensive fibrosis Atherosclerosis of anomalous feeding arteries ELS Resembles normal lung with bronchial, bronchiolar, and alveolar dilatation Intrinsic pulmonary airway malformation type 2 (50%) CLINICAL ISSUES Presentation Most common signs/symptoms Signs and symptoms of pulmonary infection 906

Diagnostic Imaging Cardiovascular Fever Productive cough Chest pain, may be pleuritic Other signs/symptoms Hemoptysis 15-20% asymptomatic: Incidental imaging abnormality Demographics Age ILS: Any age 50% > 20 years of age ELS: Neonates and infants Majority diagnosed by age of 6 months Gender ILS: M = F ELS: M:F = 4:1 Natural History & Prognosis ILS: Excellent prognosis following surgical excision ELS: Excellent prognosis after excision in absence of congenital anomalies or pulmonary hypoplasia Treatment ILS: Lobectomy Symptomatic lesions, recurrent infection Preoperative imaging for identification of systemic feeding vessels ELS: Surgical excision SELECTED REFERENCES 1. Wei Y et al: Pulmonary sequestration: a retrospective analysis of 2625 cases in China. Eur J Cardiothorac Surg. 40(1):e39-42, 2011 2. Biyyam DR et al: Congenital lung abnormalities: embryologic features, prenatal diagnosis, and postnatal radiologicpathologic correlation. Radiographics. 30(6):1721-38, 2010 3. Lee EY et al: Multidetector CT evaluation of congenital lung anomalies. Radiology. 247(3):632-48, 2008 4. Newman B: Congenital bronchopulmonary foregut malformations: concepts and controversies. Pediatr Radiol. 36(8):773-91, 2006 P.11:25

Image Gallery

(Left) Posteroanterior radiograph of an asymptomatic patient demonstrates an ill-defined opacity in the left lower lung zone in a retrocardiac location. (Right) Lateral radiograph of the same patient shows the opacity in the posterior left lower lobe. CECT (not shown) revealed a feeding artery arising from the descending thoracic aorta and pulmonary venous drainage characteristic of an intralobar sequestration.

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(Left) Axial CTA of a patient with a right lower lobe mass shows an artery arising from the descending thoracic aorta proximal to the diaphragmatic hiatus. (Right) Axial CTA MIP of the same patient at a more inferior level demonstrates the systemic artery extending into the right lower lobe mass and branching into multiple smaller arterial branches . The most common imaging manifestation of pulmonary sequestration is lower lobe consolidation or mass.

(Left) Graphic shows the morphologic features of extralobar sequestration characterized by supernumerary lung tissue invested in pleura and located in the inferior left hemithorax. There is no communication with the tracheobronchial tree, and the lesion is supplied by the systemic circulation. (Right) Axial CECT of a patient with extralobar sequestration demonstrates a mass-like opacity in the left lower lobe. Note the systemic feeding artery and draining vein .

Branch Pulmonary Artery Stenosis Key Facts Terminology Stenosis of pulmonary artery (PA) branches Imaging Focal web-like or long-segment tubular narrowing of PA branches Collateral aortopulmonary circulation to lung in chronic PA stenosis CTA or MRA: Best imaging tool Conventional angiography: Pressure gradient within pulmonary arterial system is diagnostic Top Differential Diagnoses Adult-acquired PA stenosis 908

Diagnostic Imaging Cardiovascular Pulmonary arterial hypertension Pulmonary atresia Pulmonary stenosis Pulmonary vein stenosis Pathology Most commonly congenital in etiology Associated with congenital heart disease Component of clinical syndromes Acquired Following pulmonary revascularization procedures Clinical Issues Much more commonly encountered and described in pediatric population Children: Symptoms related to congenital heart disease Adults: Progressive dyspnea and fatigue Treatment Surgical revascularization for proximal PA stenosis/atresia associated with congenital heart disease Percutaneous balloon angioplasty ± stent in select cases

(Left) Posterior volume rendering of 3D reformation demonstrates a central posterior stenosis in a patient with history of Blalock-Taussig shunt placement. Although branch pulmonary artery (PA) stenosis is typically congenital in etiology, revascularization procedures such as the Fontan procedure and Blalock-Taussig shunt placement may result in acquired branch PA stenosis. (Right) Posteroanterior chest radiograph shows focal dilatation of the right interlobar PA in a patient with a proximal PA stenosis.

(Left) Coronal reformat CTA shows focal stenosis of the truncus anterior branch 909

of the right PA. Note the

Diagnostic Imaging Cardiovascular poststenotic dilatation . (Right) Pulmonary angiography demonstrates multiple regions of stenosis and poststenotic dilatation involving the segmental and subsegmental PAs extending into the left lung. PA stenosis may manifest as focal web-like or long-segment tubular narrowing of the PAs. P.11:27

TERMINOLOGY Definitions Stenosis of pulmonary artery (PA) branches IMAGING General Features Best diagnostic clue Focal web-like or long-segment tubular narrowing of PA branches Collateral aortopulmonary circulation to lung in chronic PA stenosis Radiographic Findings Radiography Heart size is typically normal Right heart enlargement may be seen in chronic severe PA stenosis Filling of retrosternal clear space Pulmonary vascularity is usually normal Decreased pulmonary vascularity may be seen in severe PA stenosis Poststenotic dilatation may occasionally be evident CT Findings NECT May see calcification in setting of mediastinal fibrosis Right heart enlargement in chronic severe obstruction and resultant right ventricular failure HRCT Mosaic attenuation may be seen in setting of chronic pulmonary arterial hypertension (PAH) CTA Best test for evaluation of potential underlying mediastinal lesions causing extrinsic compression Focal or tubular narrowing of PAs Narrowing of corresponding pulmonary veins may be seen in setting of extrinsic compression Best test to depict aortopulmonary collateral vessels Gated CTA may demonstrate associated congenital cardiac abnormalities MR Findings T1WI Useful for evaluating soft tissue anatomy of mediastinum or lesions surrounding stenosed PAs T2WI Useful for characterizing lesions creating extrinsic compression of PAs MRA May demonstrate focal or diffuse PA stenosis Focal or diffuse pulmonary vein stenosis may also be evident Aortopulmonary collateral circulation in chronic PA stenosis Contrast-enhanced 3D MRA technique is shown to be as accurate as conventional angiography for detecting pulmonary stenoses and aortopulmonary collaterals Phase-contrast velocity measurement is important in characterizing hemodynamic significance of PA stenosis and branch PAs Peak systolic velocities > 1.5 mm/s imply hemodynamically significant stenosis Cine gradient-echo imaging may be helpful in characterizing associated congenital cardiac abnormalities Echocardiographic Findings Echocardiogram Echocardiography has limited usefulness due to limited acoustic window for evaluating branch PA stenosis May demonstrate associated cardiac abnormalities Atrial septal defect Pulmonary valve stenosis Pulsed Doppler

910

Diagnostic Imaging Cardiovascular Parasternal and subcostal views most accurately determine PA flow velocities across valve and main PA stenoses Peripheral stenoses are not directly visualized Angiographic Findings Conventional Pressure gradient within pulmonary arterial system is diagnostic Defines location, length, number, and severity of stenotic segments Balloon angioplasty in select cases only Proximal and well-localized severe stenoses Possible stent placement Nuclear Medicine Findings V/Q scan Tc-99m macroaggregated albumin Segmental and subsegmental defects Imaging Recommendations Best imaging tool CTA or MRA DIFFERENTIAL DIAGNOSIS Adult-Acquired Pulmonary Artery Stenosis Chronic pulmonary embolism Vasculitis Takayasu arteritis Young to middle-aged women PAs affected in > 50% of cases Usually bilateral and multifocal Predilection for upper lobe branches Connective tissue disorders Scleroderma Rheumatoid arthritis Systemic lupus erythematosus Behçet disease Wegener granulomatosis Allergic angiitis and granulomatosis Pulmonary Arterial Hypertension Enlarged pulmonary trunk and central PAs HRCT: Evaluates precapillary and postcapillary etiologies of PAH CTA: Enlargement of pulmonary trunk > 30 mm Pulmonary Atresia Congenital malformation characterized by failed development of pulmonary valve orifice 2 distinct types based on status of interventricular septum P.11:28

Pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries (MAPCAs) Hypoplastic/absent PAs MAPCAs supply 1 or both lungs Pulmonary atresia with intact ventricular septum Normal-sized PAs supplied by ductus arteriosus and patent foramen ovale Best diagnostic clue: Right ventricular outflow tract (RVOT) ± pulmonary valve atresia Extreme boot-shaped configuration of heart on chest radiography Pulmonary Stenosis Lesion resulting in obstruction of RVOT and poststenotic dilatation of pulmonary trunk and left PA Best diagnostic clue: Enlargement of pulmonary trunk and left PA Pulmonary Vein Stenosis Typically postprocedural in etiology Postradiofrequency ablation of ectopic atrial foci Following reanastomosis of anomalous pulmonary vein PATHOLOGY General Features 911

Diagnostic Imaging Cardiovascular Etiology Congenital Most common cause of branch PA stenosis Associated with congenital heart disease Component of clinical syndromes Alagille Congenital rubella Cutis laxa Ehlers-Danlos Noonan Silver Williams Acquired Following pulmonary revascularization procedures Fontan and Blalock-Taussig shunt Mediastinal fibrosis Most commonly due to Histoplasma capsulatum infection Staging, Grading, & Classification PA stenosis may be divided into 4 types Type 1: Isolated stenosis of pulmonary trunk or left main or right main PA Type 2: Stenosis at truncal bifurcation and extending into main PAs Type 3: Multiple peripheral stenoses Type 4: Combination of central and peripheral stenoses Gross Pathologic & Surgical Features Proximal to or at site of stenosis Hardened stenotic regions Narrowing of PA branches Thickening of PA wall Distal to site of stenosis Poststenotic dilatation of PA branches Thinning of PA wall Aortopulmonary collateral circulation through bronchial arteries Microscopic Features Findings related to PAH Heath-Edwards microscopic grading Grade I: Muscularization of PAs Grade II: Intimal proliferation Grade III: Subendothelial fibrosis Grade IV: Plexiform lesions Grade V: Rupture of dilated vessels Grade VI: Necrotizing arteritis Children Fibrous intimal proliferation Medial hypoplasia Loss of elastic fibers in affected segments Adults Increase in smooth muscle cells and disorganized elastic fibers in media Luminal encroachment CLINICAL ISSUES Presentation Most common signs/symptoms Children Symptoms related to congenital heart disease Adults Progressive dyspnea and fatigue Symptoms related to PAH Demographics Age Much more commonly encountered and described in pediatric population 912

Diagnostic Imaging Cardiovascular Natural History & Prognosis Serious and long-term complication of congenital heart disease Noncardiac comorbidities often determine course and prognosis Prognosis is poor Treatment Surgical revascularization for proximal PA stenosis/atresia associated with congenital heart disease Percutaneous balloon angioplasty ± stent in select cases SELECTED REFERENCES 1. Holst JA et al: Posterior pulmonary artery bifurcation side-to-side arterioplasty for branch pulmonary artery stenosis. J Thorac Cardiovasc Surg. 144(5):1257-9, 2012 2. Amano H et al: A case of isolated peripheral pulmonary artery branch stenosis associated with multiple pulmonary artery aneurysms. Intern Med. 49(17):1895-9, 2010 3. Pelage JP et al: Pulmonary artery interventions: an overview. Radiographics. 25(6):1653-67, 2005 4. Seto T et al: [A case of the multiple peripheral pulmonary artery branch stenosis.] Nihon Kokyuki Gakkai Zasshi. 43(12):755-60, 2005 5. Horstkotte D et al: [Congenital heart disease and acquired valvular lesions in pregnancy.] Herz. 28(3):227-39, 2003 6. Bacha EA et al: Comprehensive management of branch pulmonary artery stenosis. J Interv Cardiol. 14(3):367-75, 2001 P.11:29

Image Gallery

(Left) Axial CECT shows focal stenosis of a PA branch in the left upper lobe. Note the poststenotic dilatation . Dilation of the more proximal PA is secondary to more proximal stenoses. (Right) Axial CTA demonstrates focal narrowing of the distal right main PA . PA stenosis is classified based upon the location of stenosis. Isolated right main PA stenosis is consistent with type 1 PA stenosis.

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(Left) Pulmonary angiography performed for suspected pulmonary embolism in a patient with shortness of breath shows multiple foci of mild branch PA stenosis . The examination was negative for pulmonary embolism. (Right) Axial CECT demonstrates poststenotic dilatation of peripheral PA branches extending into the left lung. Multiple peripheral PA stenoses represent type 3 PA stenosis.

(Left) Axial CECT demonstrates marked enlargement of the pulmonary trunk and segmental PAs extending into the right lung secondary to multiple stenoses. (Right) Axial CECT of the same patient shows dilated peripheral PAs in the right lower lobe. Note the alternating regions of decreased and increased attenuation in the right lung, which may be seen in the setting of chronic pulmonary arterial hypertension.

Pulmonary Arterial Hypertension Key Facts Terminology Pulmonary artery hypertension (PAH) Mean pulmonary artery pressure > 25 mm Hg at rest > 30 mm Hg during exercise Mean capillary wedge pressure and left ventricular end-diastolic pressure typically < 15 mm Hg Imaging Radiography Enlarged pulmonary trunk and central pulmonary arteries HRCT Precapillary etiologies: Emphysema, fibrosis, honeycomb lung Postcapillary etiologies: Centrilobular ground-glass nodules, pulmonary edema, pleural effusions 914

Diagnostic Imaging Cardiovascular Chronic PAH: Patchy ground-glass opacity CTA: Enlargement of pulmonary trunk (> 30 mm) Top Differential Diagnoses Congenital pulmonic valvular stenosis Idiopathic dilatation of pulmonary trunk Hilar lymphadenopathy Pathology Precapillary etiologies: Chronic pulmonary emboli, congenital left-to-right shunts, lung disease, and idiopathic PAH Postcapillary etiologies: Left heart failure and mitral stenosis Clinical Issues Poor prognosis Treatment Medical therapy: Calcium channel blockers Idiopathic PAH: Prostaglandin I2 (epoprostenol) Lung ± heart transplant

(Left) Posteroanterior chest radiograph of a patient with pulmonary artery hypertension (PAH) shows marked enlargement of the pulmonary trunk , left pulmonary artery , and right pulmonary artery . Note the “pruning” of the peripheral pulmonary arteries. (Right) Axial CECT demonstrates enlargement of the pulmonary trunk in a patient with PAH. Enlargement of the pulmonary trunk to a diameter > 30 mm is highly suggestive of PAH.

(Left) Axial NECT of a patient with longstanding PAH demonstrates enlargement of the pulmonary trunk , left pulmonary artery , and right pulmonary artery . Intimal calcification is present . (Right) Phase-contrast sagittal MR shows an enlarged pulmonary trunk and enlarged proximal left and right pulmonary arteries . 915

Diagnostic Imaging Cardiovascular Phase-contrast MR is useful for evaluating pulmonary artery morphology and determining the direction and velocities of blood flow. P.11:31

TERMINOLOGY Abbreviations Pulmonary hypertension (PH) Pulmonary arterial hypertension (PAH) Definitions Mean pulmonary artery (PA) pressure > 25 mm Hg at rest > 30 mm Hg during exercise Mean capillary wedge pressure and left ventricular end-diastolic pressure typically < 15 mm Hg IMAGING General Features Best diagnostic clue Enlarged pulmonary trunk Variable enlargement of left and right PAs Radiographic Findings Radiography General Enlargement of pulmonary trunk Left superior mediastinal convexity on frontal radiography Pruning of peripheral PA branches Cardiac silhouette Early: Normal Late: Enlargement of right atrium and ventricle Chronic PAH Intimal calcification of PA wall Lung parenchyma Precapillary etiologies Emphysema, fibrosis, honeycomb lung Postcapillary etiologies Pulmonary edema and pleural effusions CT Findings HRCT Precapillary etiologies Emphysema, fibrosis, honeycomb lung Postcapillary etiologies Centrilobular ground-glass nodules Hemorrhagic foci Cholesterol granulomas Pulmonary edema Pleural and pericardial effusions Mediastinal lymphadenopathy Chronic PAH Mosaic attenuation Differential perfusion Diminished vascularity in regions of decreased lung attenuation Ground-glass opacity not as well defined as in small airways disease CTA General Enlargement of PAs Pulmonary trunk > 30 mm Right interlobar PA > 16 mm in men; > 14 mm in women Normal PAs Pulmonary trunk: 28.6 mm Smaller than adjacent ascending aorta Left PA: 28 mm; right PA: 24.3 mm 916

Diagnostic Imaging Cardiovascular Chronic pulmonary emboli Band-like peripheral endoluminal hypoattenuation foci Schistosomiasis Cirrhosis and portal hypertension Chronic PAH Intimal calcification of PA wall Cardiac gated CTA Decreased distensibility of PA wall MR Findings Less sensitive and specific than CT More difficult to perform in dyspneic patients Phase-contrast MR Morphology of PAs Direction and velocities of blood flow Resistance to flow Regurgitant fraction PA strain Angiographic Findings Most reliable means of diagnosis Direct measurement of right-sided pressures Nuclear Medicine Findings Ventilation-perfusion scintigraphy Usually low-probability scans for pulmonary embolism High-probability scans for chronic thromboemboli Reduced quantity of particles is necessary Risk of acute right heart failure from occlusion of capillary bed Imaging Recommendations Best imaging tool CECT Quantifies PA enlargement Determines etiology Filling defects in PAs (thromboemboli) Parenchymal abnormalities Cardiac morphology Protocol advice Multiplanar imaging for accurate measurements Echocardiographic Findings Echocardiogram Right ventricular pressure overload Enlarged right atrium and ventricle Right ventricular hypertrophy Reduced global right ventricular function Interventricular septum Increased thickness Systolic flattening Interventricular septum: Posterior left ventricular wall ratio > 1 DIFFERENTIAL DIAGNOSIS Congenital Pulmonic Valvular Stenosis Enlargement of pulmonary trunk and left PA Thickening and calcification of pulmonic valve leaflets may be present Idiopathic Dilatation of Pulmonary Trunk Enlargement of pulmonary trunk ± left and right PAs P.11:32

Diagnosis of exclusion Normal right-sided pressures Hilar Lymphadenopathy Enlargement of hila 917

Diagnostic Imaging Cardiovascular Sarcoidosis, lymphoma, metastatic disease PATHOLOGY General Features Etiology Precapillary etiology Chronic pulmonary emboli Congenital left-to-right shunts Atrial and ventricular septal defects Patent ductus arteriosus Lung disease Emphysema, fibrosis, honeycomb lung Idiopathic PAH Infection: Schistosomiasis and HIV Drugs and toxins Portal hypertension Postcapillary etiology Left heart failure Mitral stenosis Mediastinal fibrosis Pulmonary venoocclusive disease Staging, Grading, & Classification Heath-Edwards microscopic grading Grade I: Muscularization of PAs Grade II: Intimal proliferation Grade III: Subendothelial fibrosis Grade IV: Plexiform lesions Grade V: Rupture of dilated vessels Grade VI: Necrotizing arteritis WHO classification WHO group I: PAH WHO group II: PAH associated with left heart disease WHO group III: PAH associated with lung disease &/or hypoxemia WHO group IV: PAH due to chronic thrombotic &/or embolic disease Microscopic Features Idiopathic PAH Plexogenic pulmonary arteriopathy Medial hypertrophy Intimal proliferation Necrotizing arteritis Pulmonary venoocclusive disease Microscopic findings of capillary hemangiomatosis Intimal fibrosis of pulmonary veins Recanalized thrombi and webs Centrilobular cholesterol granulomas in 25% of cases CLINICAL ISSUES Presentation Most common signs/symptoms Dyspnea on exertion Other signs/symptoms Fatigue, syncope, chest pain Flu-like illness may precede pulmonary venoocclusive disease Demographics Age 3rd decade of life (idiopathic PAH) Gender M:F = 1:3 (idiopathic PAH) Epidemiology Schistosomiasis is most common cause worldwide Pulmonary venoocclusive disease: 1/3 children 918

Diagnostic Imaging Cardiovascular Prevalence in men > 35 years (10%); > 65 years (25%) 1% of acute thromboemboli become chronic thromboemboli Natural History & Prognosis Diagnosis Swan-Ganz catheterization Normal resting mean PA pressure < 20 mm Hg Precapillary Elevated mean PA pressure and increased resistance Normal pulmonary capillary wedge pressure Postcapillary Elevated mean PA pressure and increased resistance Elevated pulmonary capillary wedge pressure Poor prognosis Treatment Medical therapy 30% response Calcium channel blockers Pulmonary thromboemboli Anticoagulation Inferior vena cava filter Selective thromboendarterectomy Idiopathic PAH Prostaglandin I2 (epoprostenol) Vasodilator Poor prognostic indicators on pretreatment CT Centrilobular ground-glass nodules Interlobular septal thickening Pleural and pericardial effusions Lymphadenopathy Lung ± heart transplant DIAGNOSTIC CHECKLIST Consider PAH when imaging studies demonstrate pulmonary trunk size > 30 mm Image Interpretation Pearls Evaluate mediastinum and lung parenchyma for possible etiologies SELECTED REFERENCES 1. Badesch DB et al: Pulmonary arterial hypertension: baseline characteristics from the REVEAL Registry. Chest. 137(2):376-87, 2010 2. Sanz J et al: Pulmonary arterial hypertension: noninvasive detection with phase-contrast MR imaging. Radiology. 243(1):70-9, 2007 3. Bossone E et al: Pulmonary arterial hypertension: the key role of echocardiography. Chest. 127(5):1836-43, 2005 4. Frazier AA et al: From the archives of the AFIP: pulmonary vasculature: hypertension and infarction. Radiographics. 20(2):491-524; quiz 530-1, 532, 2000 P.11:33

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(Left) Posteroanterior radiograph of a patient with a patent ductus arteriosus, a congenital left-to-right shunt, shows marked enlargement of the central pulmonary arteries and “pruning” of the peripheral arteries. (Right) Axial CECT demonstrates marked enlargement of the pulmonary arteries. PAH should be considered when the pulmonary trunk measures > 30 mm. Enlargement of the right interlobar pulmonary artery > 16 mm in men and 14 mm in women is also suggestive.

(Left) Axial CECT of a patient with chronic PAH demonstrates peripheral thrombus and calcification within the pulmonary arteries, consistent with chronic pulmonary emboli. (Right) Coronal CECT of the same patient shows extensive chronic pulmonary emboli and enlargement of the pulmonary arteries. Chronic pulmonary emboli, congenital left-to-right shunts, and lung diseases such as emphysema and fibrosis are some of the most common precapillary etiologies of PAH.

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(Left) Axial CECT of a patient with longstanding PAH shows alternating geographic regions and increased and decreased lung attenuation. The pulmonary vessels are attenuated in the regions of decreased lung attenuation. These findings are consistent with mosaic perfusion of the lungs in chronic PAH. (Right) Axial NECT demonstrates enlargement of the pulmonary arteries and the presence of intimal calcification in longstanding PAH.

Pulmonary Venoocclusive Disease Key Facts Terminology Pulmonary venoocclusive disease (PVOD) Rare cause of pulmonary arterial hypertension (PAH) resulting from fibrous intimal proliferation and occlusion of pulmonary venules Imaging Radiography Enlarged central pulmonary arteries Kerley B lines Cardiomegaly Small pleural effusions CT Thick interlobular septa and fissures Ground-glass opacities Centrilobular ground-glass nodules Main pulmonary artery > 3 cm Dilated right heart chambers Pericardial and pleural effusions Top Differential Diagnoses Pulmonary capillary hemangiomatosis Sparser septal thickening Idiopathic pulmonary arterial hypertension No interlobular septal thickening Clinical Issues Symptoms: Dyspnea, chest pain Surgical biopsy risky in PAH patients CT is helpful to distinguish PVOD from other causes of PAH Diagnostic Checklist Consider PVOD in PAH patients with septal thickening and ground-glass opacity on CT Important to report possible PVOD because PAH therapies can lead to pulmonary edema ± death

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(Left) AP chest radiograph shows pulmonary trunk enlargement and diffuse bilateral septal thickening . Pulmonary venoocclusive disease (PVOD) should be suspected in patients with findings of pulmonary hypertension and septal lines. Pulmonary capillary wedge pressures are usually normal. (Right) Axial HRCT of a patient with PVOD shows interlobular septal thickening , ground-glass opacities , and small pleural effusions . Pleural effusions in PVOD are typically small.

(Left) Axial CT of a patient with PVOD shows bilateral interlobular septal thickening , ground-glass opacities , and pulmonary trunk enlargement . (Right) Axial HRCT of a patient with PVOD shows interlobular septal thickening and ground-glass opacities . HRCT findings of PVOD are similar to those of other causes of pulmonary edema. However, findings of pulmonary arterial hypertension, such as pulmonary artery and right heart enlargement, are also present. P.11:35

TERMINOLOGY Abbreviations Pulmonary venoocclusive disease (PVOD) Definitions Rare cause of pulmonary arterial hypertension (PAH) due to fibrous intimal proliferation and occlusion of pulmonary venules and small veins IMAGING General Features Best diagnostic clue Coexistence of findings related to both PAH and pulmonary edema 922

Diagnostic Imaging Cardiovascular Radiographic Findings Enlarged pulmonary trunk and main pulmonary arteries Kerley B lines Patchy airspace opacities Cardiomegaly but normal left atrium and ventricle Pleural effusions CT Findings Findings of PAH Dilatation of main pulmonary artery (> 3 cm in diameter) Right atrial and ventricular enlargement Pericardial effusion Findings of pulmonary edema Ground-glass opacity Diffuse, patchy, or perihilar Thickened interlobular septa and fissures Centrilobular ground-glass nodules Pleural effusions Mediastinal lymph node enlargement Normal size left atrium and left ventricle Normal caliber pulmonary veins Imaging Recommendations Best imaging tool CT useful for distinction of PVOD from other causes of PAH DIFFERENTIAL DIAGNOSIS Pulmonary Capillary Hemangiomatosis Proliferation of capillary channels within alveolar walls Septal lines sparser than in PVOD Hemorrhagic pleural effusion and hemoptysis (not reported in PVOD) Idiopathic Pulmonary Arterial Hypertension Female predominance Pulmonary findings on CT are less frequent than in PVOD Centrilobular ground-glass nodules corresponding to cholesterol granuloma (result of hemorrhage) in severe cases No septal or fissural thickening Better prognosis than PVOD PATHOLOGY General Features Etiology Associated with Chemotherapeutic agents: Bleomycin, mitomycin Bone marrow, stem cell transplantation Tobacco exposure Connective disease, sarcoidosis, Langerhans cell histiocytosis HIV infection Can be idiopathic Genetics Mutations in bone morphogenetic protein receptor 2 (BMPR2) gene in some patients Associated abnormalities Bronchoalveolar lavage: Hemosiderin-laden macrophages related to occult hemorrhage Microscopic Features Fibrous remodeling of intima that narrows or occludes lumen of septal veins and preseptal venules Dilated pleural and pulmonary lymphatic vessels CLINICAL ISSUES Presentation Most common signs/symptoms Progressive dyspnea on exertion Chest pain Normal or low pulmonary capillary wedge pressure Low carbon monoxide diffusion capacity of lungs 923

Diagnostic Imaging Cardiovascular Demographics Age Any age, usually < 50 years Gender M≥F Epidemiology Rare, estimated 0.1-0.2 cases/million 5-10% of patients initially diagnosed with idiopathic PAH Natural History & Prognosis Very poor prognosis: Most patients die within 2 years of diagnosis Surgical lung biopsy risky in severe PAH Treatment Lung transplantation is only curative intervention PAH therapies (prostacyclins, calcium channel blockers, endothelin receptor antagonists, etc.) can lead to acute pulmonary edema and possible death Continuous intravenous epoprostenol can be initiated with diuretics under close monitoring SELECTED REFERENCES 1. Huertas A et al: Pulmonary veno-occlusive disease: advances in clinical management and treatments. Expert Rev Respir Med. 5(2):217-29; quiz 230-1, 2011 2. Frazier AA et al: From the Archives of the AFIP: pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis. Radiographics. 27(3):867-82, 2007

Section 12 - Arterial Introduction and Overview Approach to Congenital and Acquired Diseases of the Aorta > Table of Contents > Section 12 - Arterial > Introduction and Overview > Approach to Congenital and Acquired Diseases of the Aorta Approach to Congenital and Acquired Diseases of the Aorta Santiago Martínez-Jiménez, MD Introduction The aorta is commonly affected by congenital and acquired processes. Aortic abnormalities may be completely asymptomatic or may manifest with a myriad of signs and symptoms that may become life-threatening emergencies. While clinical assessment of patients with aortic pathology can provide valuable information, radiological assessment remains fundamental in establishing a definitive diagnosis and determining appropriate treatment. Consequently, the cardiovascular imager should be familiar with multimodality aortic imaging and must recognize true pathologic findings and distinguish them from normal variants. Accurate imaging assessment will greatly impact clinical decisions related to appropriate management (i.e., medical or surgical) as well as the optimal timing for intervention. Congenital Aortic Pathology The assessment of patients with congenital aortic pathology can be challenging. Common congenital aortic abnormalities are often entirely asymptomatic (e.g., right aortic arch with aberrant left subclavian artery) and are frequently detected incidentally on imaging studies. However, it is not uncommon for these lesions to simulate other abnormalities that usually require treatment (e.g., right aortic arch with aberrant left subclavian artery and diverticulum of Kommerell may simulate a double aortic arch or a mediastinal neoplasm). Congenital aortic pathologies may also produce symptoms. In such cases, clinical manifestations can be severe and tend to occur early in life (e.g., double aortic arch with airway obstruction or right aortic arch with mirror-image branching and associated congenital heart disease). Chest radiography often is the initial imaging study as it may allow detection of other common thoracic disorders that may produce similar symptoms (e.g., pneumonia, pneumothorax, pleural effusion, etc.). However, CT and MR are superior to chest radiography in the assessment of anatomic detail and complications, and they remain the standard of diagnosis when aortic pathology is suspected. Other complementary imaging studies, such as echocardiography, may also be helpful, especially for assessment of the aortic root. Acquired Aortic Pathology Imaging plays a critical role in the assessment of symptomatic patients with acquired aortic pathology. Acute aortic syndrome (AAS) and aneurysm are the most commonly diagnosed entities affecting patients with acquired aortic 924

Diagnostic Imaging Cardiovascular pathology. Classically, AAS manifests with acute and severe chest pain in the setting of arterial hypertension. AAS comprises four entities, viz., aortic dissection, incomplete aortic dissection, intramural hematoma, and penetrating aortic ulcer. These entities may represent a continuum of the same pathology (i.e., aortic dissection), which may ultimately result in aortic rupture. However, it is often useful to view these processes as separate entities. Unfortunately, there are other entities that must be considered in patients who present with chest pain with or without arterial hypertension, such as acute coronary syndrome and aortic aneurysm. It may be impossible to differentiate these entities based on clinical grounds. The added value of imaging is the identification of specific crosssectional imaging findings associated with each entity. Patients with acute aortic syndrome are typically initially assessed with chest radiography. Chest radiographs can provide timely information on the presence or absence of other etiologies for chest pain, such as pneumothorax, pleural effusion, pneumonia, lung cancer, etc. If a satisfactory explanation is not found on radiography or if the clinical presentation is highly suspicious for AAS or aortic aneurysm, cross-sectional imaging is usually undertaken. Given its widespread availability and fast acquisition, CT is often the mainstay of diagnosis. However, MR is as accurate as CT in the assessment of AAS or aneurysm. While acute coronary syndrome may clinically mimic AAS or aneurysm, affected patients may be identified with other methods, such as ECG and cardiac enzymes. The main differential diagnosis of AAS is complicated aortic aneurysm. It should be noted that aortic aneurysm is frequently considered part of AAS, given the fact that aortic aneurysm may also result in aortic rupture. Further, affected patients frequently present with arterial hypertension. However, as opposed to AAS, aortic aneurysm is often a clinically silent disease that may give rise to symptoms in the setting of complications. Aortic aneurysm can occur in different clinical scenarios. The most common cause of aortic aneurysm is atherosclerosis. While atherosclerotic aneurysms can occur anywhere in the aorta, they are most common in the descending aorta. On the other hand, there is a very high incidence of ascending aortic aneurysm in patients with Marfan syndrome (and other connective tissue disorders) and bicuspid aortic valve. As such, surveillance of the population at risk is often recommended so that complications can be detected and addressed early in the disease. Finally, the so-called mycotic aortic aneurysm, which pathologically resembles a pseudoaneurysm, is frequently suspected in patients with endocarditis and aortic contour abnormalities on chest radiography. Another common acquired aortic pathology is related to trauma, the so-called traumatic aortic injury (TAI). TAI manifests with various imaging findings ranging from subtle intimal irregularities to overt aortic pseudoaneurysm. The approach to patients with TAI is well established but may vary slightly among institutions. While today CTA is the gold standard for the diagnosis of TAI, the assessment of patients with trauma often starts with chest radiography as it allows the prompt diagnosis and management of other associated life-threatening conditions, such as pneumothorax and hemothorax. Patients with vasculitis (e.g., Takayasu and giant cell arteritis) are often clinically symptomatic, and imaging is undertaken to determine the extent of disease, particularly in the setting of aortitis. Both CTA and MR are excellent imaging techniques to establish the presence of aortic wall thickening or, in longstanding cases, complications such as aneurysmal dilatation. However, MR remains superior to CTA when assessing mural enhancement. Selected References 1. Castañer E et al: Imaging findings in pulmonary vasculitis. Semin Ultrasound CT MR. 33(6):567-79, 2012 2. Vilacosta I et al: Acute aortic syndrome: a new look at an old conundrum. Postgrad Med J. 86(1011):52-61, 2010 3. Mirvis SE: Thoracic vascular injury. Radiol Clin North Am. 44(2):181-97, vii, 2006 P.12:3

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(Left) PA chest radiograph in a patient with right aortic arch , aberrant left subclavian artery, and diverticulum of Kommerell exemplifies how a relatively benign congenital abnormality may simulate a more complex one, such as a double aortic arch. In this case, the diverticulum of Kommerell simulates a coexistent left aortic arch. (Right) Axial bright blood MR (SSFP) in the same patient shows right aortic arch , aberrant left subclavian artery, and diverticulum of Kommerell .

(Left) Axial CTA of the chest in a patient with type B intramural hematoma (IMH) shows concentric thickening along the descending aorta. (Right) Axial NECT of the chest in the same patient with type B IMH shows concentric hyperdensity consistent with IMH. Differentiation of IMH from aortic vasculitis may not be possible on CTA. NECT is often indicated in assessment of the aorta as it allows differentiation. Only IMH exhibits hyperdensity on NECT.

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(Left) Axial CTA of the chest in a patient with Takayasu arteritis shows concentric thickening of the aorta. (Right) Coronal MIP reformation from MRA in the same patient with Takayasu arteritis shows narrowing of the left carotid artery origin, nonopacification of the left subclavian artery, and filiform left axillary artery due to extensive arteritis affecting those vessels. Both CT and MR are excellent diagnostic methods to assess patients with aortic vasculitis.

Approach to Acute Aortic Syndrome > Table of Contents > Section 12 - Arterial > Introduction and Overview > Approach to Acute Aortic Syndrome Approach to Acute Aortic Syndrome Suhny Abbara, MD, FSCCT Christopher M. Walker, MD Introduction Acute aortic syndrome may be caused by a variety of differing disease processes affecting the aortic wall that usually manifest with similar clinical symptoms, including acute chest &/or back pain. In the most accepted classification, there are three diseases that make up acute aortic syndrome, namely, aortic dissection, intramural hematoma, and penetrating atherosclerotic aortic ulcer. Some authors have proposed including three additional entities: Aortitis, intraluminal aortic thrombus, and intimal tear from trauma. For the purposes of this introduction, we will focus on the three original entities. Knowledge of normal aortic wall anatomy is central to understanding the different disease processes that make up the acute aortic syndrome. The aortic wall is composed of three layers, the tunica intima, tunica media, and tunica externa or tunica adventitia. These are commonly referred to as the intima, media, and adventitia. The intima is the innermost layer; it is composed of thin endothelial cells on a basement membrane. The media is the thickest layer and is composed of smooth muscle cells bounded by an internal and external elastic lamina. The media is responsible for giving the aorta its elastic properties. The adventitia is the thin outermost layer of the aorta; it is composed of collagen fibers and nerves. The aortic wall blood supply comes from small vessels called the vasa vasorum that travel within the adventitia and outer aspect of the media. Aortic Dissection Aortic dissection is the most common and most deadly acute aortic syndrome, with an overall incidence of 0.2-0.8% in the population. Early diagnosis and treatment are critical as 75% of patient deaths occur in the first two weeks following presentation. Aortic dissection is caused by an intimal tear within an already weakened aortic wall. Blood enters through the defect into the medial layers and propagates (or dissects) caudally and cranially, causing the formation of a “false” lumen. The term “true lumen” is used to differentiate the false lumen from the original aortic lumen. Risk factors for aortic dissection include age, hypertension, cocaine use, pregnancy, aortic coarctation, or other disease processes that weaken the aortic wall, such as Marfan syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome, or other connective tissue diseases. The classic clinical presentation is chest pain radiating to the back, although patients may also present with chest pain without radiation, dyspnea, &/or syncope. Acute aortic dissection is defined by symptoms lasting less than two weeks whereas chronic aortic dissection is defined by symptoms lasting longer than two weeks. Intramural Hematoma (IMH) 927

Diagnostic Imaging Cardiovascular Intramural hematoma is uncommon, comprising about 10-20% of patients with acute aortic syndrome. It is characterized by hemorrhage within the media of the aortic wall that is usually caused by spontaneous bleeding from the vasa vasorum. In contradistinction to aortic dissection, there is no intimal tear with intramural hematoma and no flow-containing false lumen. Hypertension is the leading risk factor for developing an intramural hematoma, and similar to aortic dissection, patients present with severe chest pain radiating to the back. Penetrating Aortic Ulcer (PAU) PAU is an ulceration of an atheromatous plaque that has eroded through the inner intima to reach the media of the aortic wall. There is often associated intramural hematoma. Ninety percent of PAUs occur in the descending thoracic aorta. The ascending aorta is likely relatively “protected” from atherosclerosis due to rapid blood flow from the left ventricle. Some authors hypothesize that further enlargement of the PAU and extension beyond the adventitia is responsible for many thoracic aortic pseudoaneurysms. PAU is most commonly seen in elderly men with hypertension. Presentation is similar to that of aortic dissection or intramural hematoma with severe chest pain that often radiates to the back. Diagnosis Chest radiograph is the initial imaging test performed in the majority of patients presenting with acute chest pain. The most reliable radiographic signs of aortic pathology include a widened mediastinum, interval displacement of intimal calcification, and abnormal aortic contour. Unfortunately, the chest radiograph is neither sufficiently sensitive nor specific for excluding aortic pathology. Currently, multidetector computed tomography (MDCT) has superseded MR and transesophageal echocardiography as the test of choice for patients with suspected aortic pathology because of its rapid image acquisition, widespread availability, and easier monitoring of unstable patients. MDCT has the added benefit of diagnosing nonaortic pathology which also may lead to chest pain. Aortic dissection is diagnosed by direct visualization of the dissection flap separating a true and false lumens. Several features are useful to differentiate true from false lumens. The true lumen is generally smaller than the false lumen, more densely opacified, and located along the posterolateral aspect of the descending thoracic aorta. Conversely, the false lumen has a larger cross-sectional area, may be thrombosed, has linear strands of tissue similar in density to the intimal flap (“cobweb” sign), and may demonstrate the “beak” sign. Intramural hematoma is best diagnosed on the noncontrast scan as the high-density lesion is often obscured when there is intraluminal contrast. The most common imaging appearance is a crescentic or circumferential high-density lesion within the aortic wall. The hematoma may displace intimal calcification inward. The aortic lumen is often of normal caliber, but it may be narrowed. It is important to document the location (Stanford type A or B) and the extent of involvement. PAU is a contrast-filled outpouching extending into the media of the aortic wall. The lesion is usually associated with extensive atherosclerotic plaque. It is important to distinguish PAU from an aortic pseudoaneurysm caused by trauma or infection. Consider a mycotic pseudoaneurysm when there is periaortic fat stranding and leukocytosis. Consider a traumatic pseudoaneurysm in the setting of trauma or when the outpouching occurs at a location predisposed to traumatic injury (e.g., ligamentum arteriosum, aortic root, or diaphragmatic hiatus). PAU often enlarges over time and may extend beyond the aortic wall to become a pseudoaneurysm. P.12:5

Classification There are two classification systems currently in use, DeBakey and Stanford. The systems are based on the location of the intimal tear/hematoma and the extent of aortic involvement. The Stanford system is favored and has replaced the original DeBakey classification as it dictates proper patient management. The Stanford system is not based on the location of the intimal tear but rather on whether the ascending aorta is involved by the disease process. Stanford type A involves the ascending aorta and usually requires immediate surgery or endovascular therapy whereas Stanford type B does not involve the ascending aorta and is generally managed medically. Lesions involving the aortic arch but not the ascending aorta are classified as Stanford type B. The DeBakey classification is divided into three groups. Type 1 lesions originate in the ascending aorta and extend into the descending thoracic aorta (Stanford A). Type 2 lesions originate in and involve only the ascending aorta (Stanford A), and type 3 lesions originate in and involve only the descending aorta (Stanford B). Suggested MDCT Protocol for Suspected Aortic Dissection The imaging protocol usually encompasses a noncontrast low-dose acquisition to detect intramural hematoma and to differentiate calcification from contrast on enhanced scans. Thicker slices are usually reconstructed to limit noise The arterial phase imaging is best performed with bolus tracking and ECG gating or triggering if ascending aortic pathology is suspected to avoid pulsation artifact that can mimic dissection (pseudoflaps). The use of high-pitch dualsource acquisition or whole-heart axial acquisition is most useful if scanner technology allows this, because motionfree images can be acquired at low radiation doses. Alternatively, the entire aorta can be scanned without gating, 928

Diagnostic Imaging Cardiovascular immediately followed by a gated acquisition that is limited to the aortic root, which minimizes the net radiation dose. Thin-section reconstructions are recommended for arterial phase CTA. Delayed (1 minute) low-dose acquisitions can be helpful to differentiate a thrombosed false lumen from slow flow within a false lumen, and they may aid in demonstrating extravasation in some circumstances. Thicker slices are usually reconstructed to limit noise Reporting The pathology type (dissection, intramural hematoma, or PAU), location, maximal aortic diameter, presence of atheroma or thrombus, extension into branch vessels, secondary signs of end-organ ischemia, and signs of aortic rupture (e.g., mediastinal or pericardial blood, contrast extravasation, or hemothorax) need to be reported. Pitfalls in Diagnosis There are multiple imaging artifacts that mimic the intimal flap of aortic dissection. The most widely seen is pulsation artifact caused by movement of the ascending aorta during end-systole and end-diastole. This artifact is lessened through the use of ECG gating or a 180° linear interpolation reconstruction algorithm. Too much contrast in the SVC may cause streak artifact, which may mimic aortic dissection. Too little arterial enhancement may lead to a falsenegative examination. The major pitfall in diagnosing intramural hematoma is lack of a noncontrast examination. Prognosis The mortality rate for type A aortic dissection is high, reaching 90% in untreated patients with an early mortality rate of approximately 1-2% per hour. Mortality decreases substantially, to 40%, in treated individuals. Type B aortic dissection is much more favorable with about 85% of patients being alive at one year with appropriate medical management. Complications There are four common life-threatening complications of Stanford type A dissections caused by propagation of the intimal flap: Pericardial hemorrhage with tamponade, aortic valve rupture with severe aortic regurgitation, coronary artery dissection with resultant myocardial infarction, and carotid artery dissection with stroke. Aortic dissection can also be fatal by causing end-organ ischemia in the abdominal vasculature. There are two main mechanisms that lead to end-organ hypoperfusion: Direct dissection flap extension into the mesenteric vasculature and dynamic occlusion due to a dissection flap acting like a curtain in front of the mesenteric or renal artery. Aortic dissection and PAU can also rupture into the mediastinum or pleural space, leading to rapid exsanguination. Treatment There are three accepted treatment options for the acute aortic syndrome: Surgery, endovascular therapy, and medical management with blood pressure control. All patients receive medications (e.g., β-blockers) directed at reduction of blood pressure to limit disease progression. Emergent surgery is the mainstay treatment option for most Stanford type A lesions due to its survival benefit over medical management. The goals of surgery are to excise and obliterate the entry point to the false lumen and to reconstitute the aorta by placement of an interposition graft into the aorta. Aortic valve replacement or repair is considered in the setting of aortic valve insufficiency. Medical therapy is the gold standard for uncomplicated type B lesions. It consists of aggressive blood pressure control. Endovascular therapy with stent grafting is being increasingly utilized in the setting of complicated type B aortic dissection (i.e., mesenteric, renal, or lower extremity ischemia; enlarging PAU; or persistent pain refractory to medical therapy). Surveillance Follow-up imaging is typically required to exclude complications from therapy or document disease progression. Surveillance of the aorta is ideally performed with either CTA or MR depending on patient age. Patients with treated acute aortic dissection may be imaged at one and six months and yearly thereafter. Patients with chronic dissection are imaged at discharge and yearly for up to three years, or when symptoms occur. Patients with acute intramural hematoma or PAU may be imaged before discharge and then at one, three, and six months, and yearly thereafter. P.12:6

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(Left) Graphic depicts the 3 diseases that traditionally encompass the acute aortic syndrome. On the left, an intramural hematoma without intimal tear is illustrated; in the middle is a PAU with adjacent focal hematoma; and on the right is a classic aortic dissection with intimal tear. (Right) Axial NECT shows thickening of the ascending aortic wall with associated high density (Stanford type A intramural hematoma). The calcification marks the location of the aortic wall intima.

(Left) Axial NECT shows a nearly complete circumferential crescent of high density within the descending thoracic aorta (Stanford type B intramural hematoma). (Right) Axial CECT from the same patient shows thickening of the descending thoracic aortic wall from intramural hematoma. Note that contrast within the aortic lumen makes it difficult to appreciate the high density within the aortic wall, explaining why noncontrast CT is a required part of the protocol.

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(Left) Axial and volume-rendered CTA images show a saccular outpouching of contrast from the descending thoracic aorta (penetrating aortic ulcer). There is associated intramural hematoma . (Right) Axial CTA shows an outpouching of contrast with a narrow neck from the proximal descending thoracic aorta (penetrating aortic ulcer), which does not extend beyond the aortic wall. There is associated atheroma and thickening of the aortic wall, likely intramural hematoma. P.12:7

(Left) Sagittal CECT shows thickening of the descending thoracic aortic wall from an intramural hematoma. (Right) Graphic depicts the Stanford and DeBakey classification systems used in aortic dissection. DeBakey type 1 involves both the ascending and the descending segments of thoracic aorta, type 2 only the ascending aorta, and type 3 only the descending aorta. The Stanford system divides lesions into those that involve the ascending aorta (type A) and those that do not (type B).

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(Left) Axial CECT demonstrates aortic dissection of the descending thoracic aorta but normal ascending aorta (Stanford type B). Note the larger false lumen with a “beak” sign and smaller true lumen . (Right) Axial CTA shows type A dissection with a thin flap within the dilated ascending aorta delineating the smaller true lumen . Note the displaced intimal calcification in the flap within the descending thoracic aorta .

(Left) Axial nongated CTA shows a dilated ascending aorta with pseudodissection from a pulsation artifact. Note the similar pulsation artifacts in the superior vena cava and main pulmonary artery . (Right) Axial CECT shows a beam-hardening streak artifact from high-density contrast within the superior vena cava and a pulsation artifact causing pseudodissection in the ascending aorta . A similar pulsation artifact is noted in the main pulmonary artery. P.12:8

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(Left) Axial CTA shows intimal flaps from a Stanford type A aortic dissection extending into the left common carotid and left subclavian arteries. The false lumen of the left common carotid artery is void of contrast, which may be due to slow flow or thrombosis. Enhancement on delayed imaging would prove slow flow. (Right) Axial FLAIR MR in the same patient shows high signal intensity within the left parietooccipital lobe due to embolic infarction.

(Left) Axial CTA shows a Stanford type A dissection within the ascending aorta and high-density pericardial fluid indicative of hemopericardium . A descending aortic dissection flap is also present. (Right) Axial CTA from the same patient shows the dissection extending into the abdominal aorta and superior mesenteric artery . Note the dense contrast refluxed and layering in the superior vena cava due to pericardial tamponade.

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(Left) Axial CTA shows a Stanford type A aortic dissection with the torn intimal flap prolapsing through the aortic valve, leading to severe aortic regurgitation. The 4 life-threatening complications include myocardial infarction, stroke, pericardial tamponade, and severe aortic insufficiency. (Right) Axial CTA shows a Stanford type A dissection involving the ascending and descending segments of the thoracic aorta. Ascending aorta dilation narrows the right pulmonary artery . P.12:9

(Left) Axial CECT shows a traumatic aortic transection with pseudoaneurysm of the proximal descending thoracic aorta. It is important to differentiate this entity from penetrating aortic ulcer. Most traumatic aortic injuries occur at the isthmus and may have an associated pseudoaneurysm, intraluminal filling defect, or active contrast extravasation. (Right) Oblique aortogram in the same patient shows a traumatic pseudoaneurysm at the ligamentum arteriosum.

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(Left) Oblique catheter aortogram shows an intimal flap that originates in the descending thoracic aorta and extends into the abdomen (Stanford type B dissection). (Right) Oblique catheter aortogram in the same patient shows repair of the dissection by placement of an endoluminal stent graft within the aorta.

(Left) Axial CTA shows the typical postoperative appearance of an interposition graft within the ascending thoracic aorta. The high-density outer ring is part of the graft. Note the persistent dissection in the descending thoracic aorta. (Right) Sagittal CTA shows thoracic endovascular aortic repair for a complicated type B aortic dissection. There is contrast along the inferior aspect of the proximal stent graft, which indicates a type Ia endoleak.

Thoracic Aorta and Great Vessels Thoracic Aorta and Great Vessel Anatomy > Table of Contents > Section 12 - Arterial > Thoracic Aorta and Great Vessels > Thoracic Aorta and Great Vessel Anatomy Thoracic Aorta and Great Vessel Anatomy Suhny Abbara, MD, FSCCT Michael T. Lu, MD TERMINOLOGY Abbreviations Common carotid artery (CCA) Internal carotid artery (ICA) External carotid artery (ECA) 935

Diagnostic Imaging Cardiovascular Subclavian artery (SCA) Vertebral artery (VA) Sinus of Valsalva (SoV) Sinotubular junction (STJ or StJxn) Ascending aorta (AsAo) Descending thoracic aorta (DsAo) Definitions Aortic root Annulus to STJ Ascending aorta Extends up to origin of brachiocephalic trunk Aortic arch or transverse aorta From brachiocephalic trunk to ligamentum arteriosum Ligamentum arteriosum is remnant of ductus arteriosus and typically lies immediately distal to origin of left subclavian artery Aortic isthmus Segment of distal aortic arch between left subclavian origin and ligamentum arteriosum Descending thoracic aorta Ligamentum arteriosum to diaphragmatic hiatus IMAGING ANATOMY Overview Thoracic aorta is divided into 4 segments from proximal to distal Aortic root Ascending aorta Aortic arch Descending thoracic aorta Aortic root extends from aortic annulus to STJ Aortic annulus Virtual ring at base of aortic root defined by lowest attachment point of aortic cusps; cusp attachment site has a complex “crown” shape Typically elliptical shape Important for sizing of aortic valve replacement Sinuses of Valsalva 3 sinuses defined by coronary origins Left coronary artery arises from left coronary sinus Right coronary artery arises from right coronary sinus Interatrial septum points toward noncoronary sinus, which is typically located posteriorly and to the right on axial images SoV is typically greatest caliber segment of thoracic aorta Sinotubular junction Anatomical landmark dividing aortic root from tubular AsAo Narrower than sinuses of Valsalva Ascending aorta extends from sinotubular junction to origin of brachiocephalic trunk Typically greatest in diameter and nearly orthogonal to axial plane at the right pulmonary artery level, a convenient and standard level of measurement Aortic arch extends from brachiocephalic trunk to ligamentum arteriosum Distal arch or aortic isthmus short (˜ 2 cm) segment between left subclavian origin and remnant of ductus arteriosus Aortic isthmus is typically narrower than adjoining aortic segments If ligamentum arteriosum cannot be identified, aortic arch can also be defined as extending past left subclavian origin Ductus diverticulum (or “bump”) is a focal smooth bulge at site of obliterated ductus arteriosus along undersurface of isthmus Normal variant that can be mistaken for traumatic aortic injury, which also occurs at this location May become aneurysmal (> 3 cm) Aortic arch branch vessels to head, neck, upper extremities, and chest wall are termed great vessels Brachiocephalic trunk (innominate artery) is 1st and largest of great vessels of aortic arch; divides into right CCA and SCA 936

Diagnostic Imaging Cardiovascular Right SCA branches include right internal mammary, VA, thyrocervical, costocervical, and long thoracic arteries, and it continues as axillary artery after margin of 1st rib Right CCA divides into ICA and ECA in neck Left CCA is 2nd great vessel from the arch Divides into ICA and ECA Left SCA is 3rd and final great vessel from arch Gives off internal mammary, VA, thyrocervical, costocervical, and long thoracic arteries and continues as axillary artery Rare (3%) thyroid ima or thyroidea ima with inferior thyroid artery arises directly from aortic arch or innominate artery as opposed to normal origin from thyrocervical trunk Descending thoracic aorta extends from distal arch to diaphragmatic hiatus, where it continues as abdominal aorta Descending aorta is typically smaller in caliber than AsAo Aortic spindle is a bulge in proximal descending aorta just distal to the isthmus Commonly seen in children but can persist into adulthood Descending aorta gives off important small arteries Bronchial arteries Intercostal arteries Supreme intercostals supply T1-T3; arise from costocervical trunk of SCAs Paired intercostals arise directly from descending aorta from T4-T12 Thoracic spinal cord supply comes from DsAo Anterior spinal artery is supplied from intercostal and bronchial arteries at T4-T5 Artery of Adamkiewicz arises from intercostal arteries at T6-T12 (75%) Esophageal, pericardial, superior phrenic, and other miscellaneous mediastinal branches Central venous anatomy Jugular veins Internal jugular veins drain head and neck; joined by external jugular veins draining face and scalp Subclavian veins P.12:11

Originate at axillary vein transition at 1st rib margin Typically valveless; joined by cephalic vein Brachiocephalic veins Formed by junction of subclavian and internal jugular veins Right is short and vertical; left is longer and crosses mediastinum anterior to great vessels Tributaries: Internal mammary, vertebral, pericardiophrenic, 1st intercostal, inferior thyroidal Superior vena cava (SVC) Formed by right and left brachiocephalic veins 6-8 cm long, up to 2 cm in diameter Azygos vein joins above pericardium; SVC enters right atrium Anatomy Relationships Aortic arch variants Right aortic arch (< 0.1%); 2 types Mirror-image branching (65%); associated with cyanotic congenital heart disease in 90% Aberrant left SCA or other great vessel origin (35%); not associated with cyanotic congenital heart disease Dilated origin of aberrant left SCA in 60%; Kommerell diverticulum; if also ligamentum arteriosum → vascular ring and tracheal compression Double (duplicated) aortic arch (< 0.1%) Arises from 3rd rather than 4th branchial arch High location in chest, near lung apex May have anomalous great vessel origins Coarctation (< 0.1%) Congenital narrowing of aortic arch, usually distal to left subclavian origin May be preductal (infantile), juxtaductal, or postductal (adult) Common with other congenital aortic pathology, such as bicuspid aortic valve and Turner syndrome 937

Diagnostic Imaging Cardiovascular Great vessel origin variants Bovine arch (20%): Left CCA may have common origin with or arise from innominate artery 4-vessel arch (5%): Left VA may arise directly from aortic arch between left CCA and left SCA rather than from left SCA Aberrant right SCA: Right SCA may arise separately from aortic arch, distal to left SCA Diverticulum of Kommerell: Dilatation at origin of aberrant right SCA; can be associated with dysphagia (dysphagia lusoria) when large ANATOMY IMAGING ISSUES Imaging Recommendations Thoracic aorta is imaged with catheter angiography, transthoracic or transesophageal echocardiography, CT angiography, and MR angiography CT angiography: Protocol may include noncontrast, arterial, and delayed-phase imaging Noncontrast images are helpful in cases of extensive calcium, prior surgery, or suspicion for intramural hematoma Delayed images better delineate mediastinal anatomy and are also helpful in postsurgical patients when there is concern for endoleak Noncontrast and delayed images are often not necessary for routine follow-up of known aortic aneurysm Thin-section (≤1.25 mm) reconstruction is preferred ECG-gated or high-pitch dual-source CT is preferred for accurate evaluation of aortic root due to cardiac motion artifact if root pathology is suspected or followed MR angiography: Contrast angiography is preferred Noncontrast sequences often give a diagnostic study and are test of choice when there is contraindication to iodinated and gadolinium contrast agent In general, for follow-up exams it is best to employ consistent imaging modality and measurement technique “Candy cane” oblique view places thoracic aorta in profile and is commonly employed for catheter, CT, and MR angiography Aortic measurement should be performed in plane orthogonal to longitudinal axis of aorta Measurements made in axial plane may be oblique to aorta and less accurate and reproducible Transcatheter Aortic Valve Implantation/Replacement Assessment For severe aortic stenosis in nonsurgical patients Transfemoral or transapical approach may be chosen CT angiography plays increasing role in sizing of aortic annulus and determining suitability of iliofemoral approach Indications and criteria are evolving PARTNER trial exclusion criteria Native aortic annulus size < 18 mm or > 25 mm Iliofemoral vessels too calcified or small to accommodate 22F or 24F introducer sheath (minimum luminal diameter of 7-8 mm, respectively) Severe aortic or iliofemoral disease that would preclude safe placement, such as aneurysm, tortuosity, extensive atheroma, or dissection Bulky calcified aortic valve leaflets in close proximity to coronary ostia RELATED REFERENCES 1. Smith CR et al: Transcatheter versus surgical aortic-valve replacement in high-risk patients. N Engl J Med. 364(23):2187-98, 2011 2. Hiratzka LF et al: 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with thoracic aortic disease. Circulation. 121(13):e266-369, 2010. Erratum in: Circulation. 122(4):e410, 2010 3. Agarwal PP et al: Multidetector CT of thoracic aortic aneurysms. Radiographics. 29(2):537-52, 2009 4. Leipsic J et al: The evolving role of MDCT in transcatheter aortic valve replacement: a radiologists' perspective. AJR Am J Roentgenol. 193(3):W214-9, 2009 5. Davies M et al: Developmental abnormalities of the great vessels of the thorax and their embryological basis. Br J Radiol. 76(907):491-502, 2003 P.12:12

Image Gallery THORACIC AORTA AND GREAT VESSELS

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(Top) Graphic demonstrates the thoracic aorta and great vessel origins. (Bottom) Graphic depicts the branches of the descending thoracic aorta, including the intercostal, esophageal, and bronchial arteries. Typically, there are both superior and inferior left bronchial arteries and a single right bronchial artery (not pictured). P.12:13

NORMAL ANATOMY OF THORACIC AORTA AND GREAT VESSELS

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(Top) Frontal chest radiograph shows a normal thoracic aorta. The aortic knob shadow is created by a superimposition of the aortic arch and proximal descending aorta. The lateral margin of the descending thoracic aorta should always be visible, but the medial margin is usually not perceptible. The lateral margin of the ascending aorta is visible as part of the right mediastinal border. (Bottom) Corresponding frontal projection of a catheter angiogram (left) and digital subtraction image (right) of the thoracic aorta illustrate normal anatomy of the aorta and great vessel origins. P.12:14

AORTIC ROOT CT ANATOMY

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(Top) “Candy cane” oblique MPR of the thoracic aorta depicts the segments of the thoracic aorta. The aortic root (red) extends from the aortic annulus to the sinotubular junction. The ascending aorta (blue) extends to the origin of the brachiocephalic trunk. The aortic arch (yellow) extends to the ligamentum arteriosum. The descending thoracic aorta (green) extends to the diaphragmatic hiatus, where it continues as the abdominal aorta. Note the smooth outpouching along the inferior surface of the aortic arch at the remnant of the ductus arteriosum. This is a normal ductus diverticulum and should not be mistaken for a traumatic aortic injury. (Middle) “Candy cane” view projection of an MRA shows a thoracic aorta. (Bottom) Three-chamber view from a CT angiogram depicts the anatomy of the left ventricular outflow tract and aortic root. P.12:15

AORTIC ROOT CT ANATOMY

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(Top) Graphic depicts the most common configuration of the aortic arch, the 3-vessel arch. (Middle) Graphic depicts common aortic arch variants. In the most common variant (upper left), the brachiocephalic trunk and left common carotid share a common origin. In the 2nd most common variant (upper right), the left common carotid arises from the brachiocephalic trunk. The left vertebral artery may arise directly from the aortic arch (lower left), between the left common carotid and subclavian arteries. The aberrant right subclavian arises from the distal aortic arch after the takeoff of the left subclavian (lower right), courses behind the trachea and esophagus to the right, and therefore may cause dysphagia (termed dysphagia lusoria). (Bottom) Digital subtraction catheter angiogram in the “candy cane” oblique view demonstrates 2 common aortic arch variants: Common origin of the brachiocephalic trunk and left common carotid (bovine arch) and a left vertebral artery arising directly from the aortic arch. P.12:16

STANDARD MEASUREMENTS

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(Top) Volume-rendered 3D CTA image in “candy cane” view from a patient with bicuspid aortic valve shows characteristic aneurysmal bowing of the ascending aorta. White lines denote standard aortic measurements planes, orthogonal to the long axis of the respective aortic segment. From proximal to distal, they include aortic annulus, sinus of Valsalva, sinotubular junction, ascending aorta at the level of the right pulmonary artery, aortic arch between the origins of the left subclavian and common carotid, and descending aorta. (Middle) Multiplanar reformation of the aortic anulus shows the typical ovoid shape of the annulus. Accurate measurement of the annulus is important for sizing aortic valve replacements. Long- and short-axis diameters are reported. Annular circumference and area may also be helpful. (Bottom) Image immediately above the aortic annulus depicts portions of the aortic valve cusps. The annulus is measured as a virtual ring defined by the attachment of the lowest points of each aortic cusp. P.12:17

AORTIC ROOT SHORT-AXIS PLANES

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(Top) Multiplanar reformat through the sinus of Valsalva. The sinus of Valsalva diameters are measured from commissure to cusp. Note that the interatrial septum points towards the noncoronary cusp in all projections. Inset shows the 3 diameter measurements (commissure to contralateral sinus) obtained in this plane. (Middle) Oblique maximum-intensity projection image through the sinus of Valsalva depicts the coronary origins. (Bottom) Oblique MPR orthogonal to the aorta at the level of the sinotubular junction shows that the sinotubular junction is of lower caliber than the sinus of Valsalva. Aortic diameters are most accurately and reproducibly measured in the plane orthogonal to the centerline of the aorta. P.12:18

STANDARD PLANES OF THE AORTA

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(Top) Axial CT image at the level of the right pulmonary artery shows the ascending and descending aorta. The ascending aorta is often greatest in diameter and nearly orthogonal to the axial plane at this level. (Middle) MPR orthogonal to the aortic long axis at the level of the aortic arch, between the origins of the left common carotid and left subclavian arteries, is the standard plane for aortic arch diameter measurement. (Bottom) Oblique MIP in C view depicts the course of the right coronary artery and the origins of the left and right coronary arteries from the sinus of Valsalva. P.12:19

TAVI/R PLANNING

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(Top) Curved multiplanar reformation high-pitch gated CTA shows the entire aorta and left ileofemoral system (large image on the right). Upper left inset is a coned down lateral radiograph of a transcatheter aortic valve replacement (TAVR). CTA is increasingly used for TAVR planning. The dimensions of the aortic annulus (mid left inset) are critical for valve sizing. The minimum luminal diameter of the iliofemoral arteries (lower left inset) and the degree of tortuosity and calcification of the aorta and iliofemoral system (right image) determine whether a transfemoral approach is possible. (Bottom) Oblique MIP depicts the coronary artery origins. Obstruction of the coronary ostia by displaced aortic valve leaflets is an infrequent but reported complication of TAVR, so the distance from the aortic annulus plane (yellow line) to the closest coronary ostium is provided. In this case, the distance to the right coronary ostium corresponds to the double-headed black arrow.

Thoracic Aortic Aneurysm Key Facts Terminology Aortic dilatation > 50% of normal diameter Imaging Radiography Ascending aortic aneurysm: Often not visible Aortic arch aneurysm: Enlarged/obscured aortic arch Descending aorta aneurysm: Focal or diffuse abnormality of left paraaortic interface Peripheral curvilinear calcification Rupture: Wide mediastinum, left pleural effusion 946

Diagnostic Imaging Cardiovascular CT Curvilinear mural calcification Crescentic mural high attenuation indicates contained/impending rupture Rupture: Hemothorax, hemopericardium, hemomediastinum Top Differential Diagnoses Tortuosity (aging) of aorta Mediastinal mass Pathology Atherosclerotic aortic aneurysm Infectious (mycotic) aneurysm Cystic medial necrosis Clinical Issues Atherosclerotic aneurysm: Most are asymptomatic Infectious (mycotic) aneurysm: Fever, leukocytosis Diagnostic Checklist Consider ruptured aneurysm: Acute chest pain, wide mediastinum, and pleural effusion on radiography Normal radiography does not exclude aneurysm or dissection; cross-sectional imaging for diagnosis

(Left) Graphics show the morphologic features of an aortic arch aneurysm with the branch vessels arising from the dilated portion of the aorta (left) and a fusiform descending thoracic aortic aneurysm (right). (Right) PA chest radiograph from a patient with atherosclerotic aneurysm of the ascending aorta shows mediastinal widening. Note that the ascending aorta overlies the right hilum, a sign concerning for mediastinal mass. Often, chest radiography is not sensitive enough to detect this abnormality.

(Left) Lateral chest radiograph from the same patient shows fullness of the retrosternal clear space. While this findings is nonspecific, it is frequently seen in anterior mediastinal masses, including ascending aortic aneurysms. 947

Diagnostic Imaging Cardiovascular (Right) Axial CTA of the chest of the same patient demonstrates marked dilatation of the ascending aorta atherosclerotic plaque along the descending aorta. P.12:21

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TERMINOLOGY Definitions Aortic dilatation > 50% of normal diameter IMAGING Radiographic Findings Radiography Ascending aortic aneurysm Often not visible Convexity of right superior cardiomediastinal silhouette Aortic arch aneurysm Enlargement or obscuration of aortic arch Hilum overlay sign Rightward tracheal deviation Descending aortic aneurysm Focal mass or dilatation with lateralization of left paraaortic interface Peripheral curvilinear calcification Ruptured aneurysm Mediastinal widening compared with prior studies Left pleural effusion CT Findings NECT Curvilinear mural calcification: Common in atherosclerotic aneurysms, absent from mycotic ones Crescent sign: Crescentic mural high attenuation indicates contained/impending rupture Rupture: Hemomediastinum, hemopericardium, or hemothorax indicates contained/impending rupture CTA Blunting of sinotubular junction (annuloaortic ectasia) often related to Marfan syndrome Crescent-shaped intraluminal thrombus Rupture: Active extravasation (uncommon) Intimomedial flap (dissection) MR Findings Similar sensitivity to CT; often used in acute setting Assessment of aortic valve and cardiac function Imaging Recommendations Best imaging tool CECT for optimal evaluation of aneurysm location and size, relationship to major branch vessels, and complications (e.g., dissection, mural thrombus, intramural hematoma, free rupture) Protocol advice Cardiac gating for anatomic and functional aortic valve assessment DIFFERENTIAL DIAGNOSIS Tortuosity (Aging) of Aorta Diffuse aortic dilatation Mediastinal Mass Hilum overlay sign; anterior mediastinal masses Curvilinear calcification typical of vascular lesions CT differentiation of neoplasm from vascular lesion PATHOLOGY General Features True aneurysm: Contains all 3 aortic wall layers Atherosclerotic aortic aneurysm Degenerative process, most common (75%) Shape: Fusiform (most common), saccular Location: Arch > descending > ascending Significantly increased risk of rupture Ascending aorta diameter > 5.5 cm 948

Diagnostic Imaging Cardiovascular Descending aorta diameter > 6.5 cm Infectious (mycotic) aneurysm Predisposing causes: Intravenous drug abuse, valvular disease, congenital aortic/cardiac disease, prior aortic/cardiac surgery, adjacent pyogenic infection, immunocompromise Most common pathogens: Salmonella spp. and Staphylococcus aureus Shape: Saccular Location: Any Cystic medial necrosis Hypertension (more common), bicuspid aortic valve, Marfan syndrome (more severe) Shape: Fusiform Location: Ascending aorta, aortic annulus (annuloaortic ectasia) Aortic regurgitation Gross Pathologic & Surgical Features Saccular: Focal mass-like aortic dilatation May result from remodeling of penetrating aortic ulcer Fusiform: Diffuse elongated aortic dilatation CLINICAL ISSUES Presentation Most common signs/symptoms Atherosclerotic aortic aneurysm: Asymptomatic (most common), chest pain, compression (hoarseness, dysphagia, atelectasis, superior vena cava syndrome) Infectious (mycotic) aneurysm: Fever, leukocytosis Acute chest pain: Rupture, dissection Demographics Gender Men > women Epidemiology Prevalence of 3-4% in patients over 65 years Treatment Risk reduction: Hypertension control, smoking cessation Indications for surgery Size criteria Ascending aorta > 5.5 cm (5 cm for familial or Marfan syndrome and bicuspid aortic valve) Descending aorta > 6.5 cm Growth rate > 1 cm per year Symptomatic patients SELECTED REFERENCES 1. Isselbacher EM: Thoracic and abdominal aortic aneurysms. Circulation. 111(6):816-28, 2005 P.12:22

Image Gallery

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(Left) Oblique sagittal MR (SSFP) of the chest of a patient with bicuspid aortic valve and ascending aortic aneurysm shows ascending aortic dilatation with preservation of the sinotubular junction , a feature that helps differentiate from dilatation due to Marfan syndrome. (Right) Oblique contrast-enhanced 3D MRA of the chest was performed in the same patient. Of all sequences, MRA provides the best overview of aneurysm extent, although motion artefact may cause some blurring of the aortic root.

(Left) PA radiograph of the chest of a patient with proximal descending thoracic aortic aneurysm shows an abnormal contour overlying the right hilum , the so-called hilum overlay sign. (Right) Lateral chest radiograph in the same patient with proximal descending aortic aneurysm shows marked tortuosity and dilatation of the proximal descending aorta . Given the high risk of rupture, all aneurysm exceeding 6.5 cm along the descending thoracic aorta require intervention.

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(Left) PA radiograph of the chest of a patient with distal descending thoracic aortic aneurysm shows lateral displacement of the left paraaortic interface . (Right) Lateral radiograph of the chest of the same patient shows dilatation of the distal thoracic aorta . While intervention of an ascending aortic aneurysm is often recommended at 5.5 cm (5.0 cm for Marfan and bicuspid aortic valve), a descending thoracic aortic aneurysm is generally repaired if > 6.5 cm. P.12:23

(Left) PA chest radiograph of a patient with a fusiform thoracoabdominal aortic aneurysm shows enlargement of the descending aorta with lateral displacement of the left paraaortic interface. Although hiatus hernia can produce a similar finding, the interface of the hernia would not involve the paraaortic interface. (Right) Axial NECT of the chest of the same patient shows an aortic aneurysm with an extensive mural and endoluminal calcified thrombus .

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(Left) Axial CTA of the chest of the same patient shows an extensive concentric endoluminal thrombus . (Right) Oblique CTA of the chest of the same patient shows a long-segment fusiform aneurysm extending along the thoracic and abdominal aorta. Assessment of the extension of the aneurysm is critical as it determines the appropriate treatment and, if needed, surgical approach. Multiplanar imaging is often of value for such purpose.

(Left) Axial MR (SSFP) of the chest of a patient with atherosclerotic aneurysms of the thoracic aorta shows dilatation of the ascending and proximal descending thoracic parts of the aorta. (Right) Axial MR (black blood) of the chest of the same patient shows dilatation of the ascending and proximal descending thoracic aorta. MRA and nonenhanced sequences, such as bright and dark blood sequences, are equally effective to diagnose an aortic aneurysm. P.12:24

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(Left) Sagittal MIP reformation from MRA after intravenous injection of gadolinium in the same patient shows fusiform aneurysms affecting the ascending and descending aorta. (Right) Sagittal 3D MRA after intravenous injection of gadolinium in the same patient shows aneurysms affecting the ascending and descending parts of the aorta. MRA remains the most accurate technique as it allows multiplanar reformations and exact anatomic detail.

(Left) Axial oblique NECT of the chest of a patient with a ruptured aneurysm shows crescentic hyperdensity along the distal aortic arch, the so-called crescent sign, which frequently represents aortic rupture, often contained. (Right) Sagittal oblique NECT of the chest of the same patient shows the crescentic hyperdensity along the distal aortic arch. In contrast to intramural hematoma, the crescentic hyperdensity tends to be more focal and associated with aneurysm.

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(Left) Axial NECT of the chest of the same patient shows also an aneurysm of the proximal descending thoracic aorta associated with high-attenuation pleural fluid as well as a hematocrit-fluid level, indicating rupture and hemothorax . (Right) Axial CTA of the chest of the same patient shows additionally an aneurysm of the proximal descending thoracic aorta associated with extensive intraluminal thrombus . P.12:25

(Left) AP radiograph of the chest of a patient with a ruptured aneurysm of the aorta shows marked mediastinal widening and moderate right pleural effusion. (Right) Axial NECT in the same patient reveals mediastinal hematoma with crescent sign along the descending thoracic aorta and left pleural effusion. These 3 CT signs are all associated with aortic rupture, which (when present) constitutes an indication of emergent repair.

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(Left) Axial CTA in the same patient shows a descending thoracic aortic aneurysm with an intraluminal thrombus , periaortic hematoma , mediastinal hematoma , and hemothorax. (Right) Axial NECT of the chest of a patient with ruptured aneurysm of the aorta shows extensive mediastinal hematoma with a large right and small left hemothoraces. These findings relate to aortic rupture and require emergent intervention. (Courtesy H. P. McAdams, MD.)

(Left) Axial CTA of the chest of the same patient shows extensive mediastinal hematoma surrounding the descending aorta and a large right and small left hemothoraces. (Courtesy H. P. McAdams, MD.) (Right) Axial CTA of the chest of the same patient shows active extravasation of contrast from the aorta to the right pleural space. While definitive for aortic rupture, this is an uncommon finding. (Courtesy H. P. McAdams, MD.)

Mycotic Aneurysm Key Facts Terminology Aneurysm arising from infection of arterial wall, usually bacterial Imaging Rapidly growing focal, saccular aneurysm arising eccentrically from aortic wall Periaortic soft tissue stranding, edema, and fluid Adjacent vertebral body or psoas abnormalities due to spread of infection Increased uptake of labeled leukocytes at site of aneurysm Top Differential Diagnoses Atherosclerotic aneurysm Inflammatory aneurysm 955

Diagnostic Imaging Cardiovascular Contained rupture Aortoenteric fistula Pathology Bacterial aortitis most commonly caused by Salmonella or Staphylococcus aureus Primary mycotic aneurysm arises from distant, unknown, or remote source of infection Secondary mycotic aneurysm arises from specific source of infection Clinical Issues Fever, signs of sepsis Positive blood cultures in most cases Surgical resection/grafting following antibiotic therapy Diagnostic Checklist Contrast-enhanced CTA or MRA with delayed images for evaluation Labeled leukocyte scan if indeterminate CTA & MRA

(Left) Axial CECT of the abdominal aorta shows periaortic low-density soft tissue with rim enhancement of the aortic wall, which is consistent with infected aortic wall and periaortic abscess. (Right) Axial CECT of the aorta in the same patient shows an area of focal small luminal outpouching (pseudoaneurysm) of the left lateral wall of the aorta with associated periaortic soft tissue swelling consistent with a mycotic aneurysm.

(Left) Oblique CTA reconstruction shows 2 focal contrast outpouchings consistent with mycotic pseudoaneurysms affecting the lateral wall of the abdominal aorta in the same patient. (Right) Coronal CTA of the aortoiliac arteries in the same patient following infrarenal aortic resection shows that the lower extremities are now perfused via a right axillary-femoral artery bypass graft and cross-femoral bypass graft . Note the absence of resected infrarenal aorta. P.12:27 956

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TERMINOLOGY Synonyms Infectious aneurysm (more appropriate term) Definitions Aneurysm arising from infection of arterial wall, usually bacterial IMAGING General Features Best diagnostic clue Rapidly growing saccular aneurysm arising eccentrically from aortic wall Location Anywhere in aorta or other vessels Tends to occur at major branchings of aorta Size Variable Morphology Usually saccular with focal involvement of artery Periaortic inflammation, abscess, mass Periaortic gas Adjacent vertebral body abnormalities due to spread of infection Radiographic Findings Radiography May reveal increased size of aorta CT Findings NECT Bacterial aortitis is rarely calcified Syphilitic aortitis shows curvilinear calcifications Periaortic soft tissue stranding, edema, and fluid are frequently present Periaortic gas Periaortic high-attenuation fluid if ruptured Adjacent vertebral body or psoas abnormalities due to spread of infection CECT ≥ 1 saccular aneurysm(s) arising from aortic wall, usually focal involvement Lobular contours of aneurysm Enhancement of periaortic soft tissue Rim enhancement in case of abscess CTA Saccular, eccentric aneurysms of variable size Enhancing periaortic soft tissue or abscess MR Findings T1WI Periaortic low signal intensity in absence of gadolinium (Gd) Aortic and periaortic enhancement following Gd, especially evident on fat-suppressed images Rim enhancement in case of abscess Adjacent bone abnormality if contiguous infection T2WI Periaortic high signal intensity on fat-suppressed T2WI Contrast-enhanced MRA ≥ 1 saccular aneurysm(s) arising from aortic wall Effacement of wall with possible leakage at rupture site In addition to MRA, delayed source images need to be analyzed to identify areas of enhancement Ultrasonographic Findings Grayscale ultrasound Useful in children or if superficial arteries are involved Focal, eccentric pseudoaneurysm Perivascular soft tissue or abscess Color Doppler Flow within aneurysm with typical yin-yang configuration 957

Diagnostic Imaging Cardiovascular Echocardiographic Findings Echocardiogram Used to rule out endocarditis as potential source of septic emboli Angiographic Findings Conventional Focal, saccular aneurysm Nuclear Medicine Findings Labeled leukocyte scintigraphy Increased uptake at site of aneurysm Imaging Recommendations Best imaging tool Contrast-enhanced CT/CTA Labeled leukocyte scintigraphy Protocol advice Obtain delayed images during contrast-enhanced CTA or MRA DIFFERENTIAL DIAGNOSIS Atherosclerotic Aneurysm Slow growing More often fusiform Often calcified No enhancement of aortic wall Inflammatory Aneurysm Distal aorta and iliac involvement Fusiform aneurysm Retroperitoneal fibrosis Contained Rupture Focal disruption or gap in aortic wall High attenuation in wall or in periphery of aneurysm Lack of enhancement Aortoenteric Fistula Most involve duodenum Periaortic soft tissue with periaortic gas Active contrast material extravasation or pseudoaneurysm Presenting as gastrointestinal bleed PATHOLOGY General Features Etiology Bacterial aortitis most commonly caused by Salmonella or Staphylococcus aureus P.12:28

Syphilitic aortitis involves ascending aorta but spares aortic sinus: Ascending aorta most common location Routes of infection Most often caused by seeding of existing lesion (atheroma or aneurysm) via vasa vasorum Direct extension from infection in vessel wall, i.e., bacterial endocarditis Invasion of aortic wall by extravascular contiguous infection, such as spinal infection or intraabdominal abscess Lymphatic spread Associated abnormalities Endocarditis Spinal or retroperitoneal infection Intraabdominal infection Staging, Grading, & Classification Classification system Primary mycotic aneurysm arises from distant, unknown, or remote source of infection Secondary mycotic aneurysm arises from specific source of infection Bacterial endocarditis (intravascular spread) Tuberculosis (contiguous spread) 958

Diagnostic Imaging Cardiovascular Gross Pathologic & Surgical Features Bacterial aneurysm Noncalcified, saccular aneurysm Thinning of aortic wall with periaortic inflammatory changes Syphilitic aneurysm Calcified lesion “Tree bark” appearance when atheroma develops in infected areas Microscopic Features Loss of intima and destruction of internal elastic lamina Media shows varying degrees of destruction Bacteria present on histology Common bacteria: Pseudomonas, Clostridium, Salmonella, Streptococcus, Aspergillus CLINICAL ISSUES Presentation Most common signs/symptoms Fever, signs of sepsis Symptoms vary greatly Nonspecific findings Low-grade fever Localized pain Positive blood cultures Blood cultures are negative in 25% of cases Demographics Epidemiology 0.7-2.6% of all aortic aneurysms Increased risk in Intravenous drug abusers Patients with history of bacterial endocarditis Immunocompromised patients Patients with vascular prostheses (valves, grafts) Natural History & Prognosis Nearly always fatal if untreated Acute rupture/hemorrhage seen in 75% Mortality rate estimated at 67% Treatment Surgical resection/grafting following antibiotic therapy May need extraanatomic bypass grafting Endovascular repair in some cases DIAGNOSTIC CHECKLIST Consider Contrast-enhanced CTA or MRA with delayed images for evaluation Labeled leukocyte scan if CTA and MRA are indeterminate Image Interpretation Pearls Focal, eccentric aneurysm of aorta Enhancing periaortic soft tissue Rim enhancement of periaortic abscess Reporting Tips Include location, size, and involvement of branch vessels Check for and report extent of contiguous infection SELECTED REFERENCES 1. Uchida N et al: In situ replacement for mycotic aneurysms on the thoracic and abdominal aorta using rifampicinbonded grafting and omental pedicle grafting. Ann Thorac Surg. 93(2):438-42, 2012 2. Iida H et al: Bacteremia causes mycotic aneurysm of the aortic arch in 110 days. Ann Thorac Surg. 83(5):1874-6, 2007 3. Taylor CF et al: Treatment options for primary infected aorta. Ann Vasc Surg. 21(2):225-7, 2007 4. Froeschl M et al: Ruptured mycotic pseudoaneurysm of the thoracic aorta. Cardiovasc Pathol. 15(2):116-8, 2006 5. Kerzmann A et al: Infected abdominal aortic aneurysm treated by in situ replacement with cryopreserved arterial homograft. Acta Chir Belg. 106(4):447-9, 2006 6. Lee KH et al: Stent-graft treatment of infected aortic and arterial aneurysms. J Endovasc Ther. 13(3):338-45, 2006 959

Diagnostic Imaging Cardiovascular 7. Palanichamy N et al: Mycotic pseudo-aneurysm of the ascending thoracic aorta after cardiac transplantation. J Heart Lung Transplant. 25(6):730-3, 2006 8. Ting AC et al: Endovascular stent graft repair for infected thoracic aortic pseudoaneurysms—a durable option? J Vasc Surg. 44(4):701-5, 2006 9. Gonzalez-Fajardo JA et al: Endovascular repair in the presence of aortic infection. Ann Vasc Surg. 19(1):94-8, 2005 10. Ting AC et al: Surgical treatment of infected aneurysms and pseudoaneurysms of the thoracic and abdominal aorta. Am J Surg. 189(2):150-4, 2005 11. Malouf JF et al: Mycotic aneurysms of the thoracic aorta: a diagnostic challenge. Am J Med. 115(6):489-96, 2003 12. Cina CS et al: Ruptured mycotic thoracoabdominal aortic aneurysms: a report of three cases and a systematic review. J Vasc Surg. 33(4):861-7, 2001 13. Locati P et al: Salmonella mycotic aneurysms: traditional and “alternative” surgical repair with arterial homograft. Minerva Cardioangiol. 47(1-2):31-7, 1999 14. Long R et al: Tuberculous mycotic aneurysm of the aorta: review of published medical and surgical experience. Chest. 115(2):522-31, 1999 15. Fichelle JM et al: Infected infrarenal aortic aneurysms: when is in situ reconstruction safe? J Vasc Surg. 17(4):63545, 1993 P.12:29

Image Gallery

(Left) Axial CTA of the abdominal aorta shows focal eccentric pseudoaneurysm affecting the juxtarenal abdominal aorta . Note the minimal periaortic soft tissue. (Right) Oblique CTA of the abdominal aorta in the same patient shows focal eccentric pseudoaneurysm . There is no significant soft tissue adjacent to the pseudoaneurysm. This patient had bacteremia and spinal infection (not shown). Surgical resection of the aorta confirmed mycotic nature of the pseudoaneurysm.

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(Left) Axial CTA of the thoracic aorta shows focal eccentric pseudoaneurysm arising from the anterior wall of the ascending aorta with associated periaortic soft tissue . (Right) Oblique CTA of the thoracic aorta in the same patient shows a focal eccentric pseudoaneurysm along the anterior wall of the ascending aorta with associated low-density soft tissue . These features are consistent with a mycotic aneurysm.

(Left) Axial CTA of the abdomen shows a pseudoaneurysm arising from a branch of the superior mesenteric artery. Note the perianeurysmal soft tissue . (Right) Coronal CTA in the same patient confirms the pseudoaneurysm arising from a branch of the superior mesenteric artery. This was secondary to a septic embolus from valvular vegetations in a 30-year-old man with endocarditis secondary to intravenous drug abuse.

Chronic Post-Traumatic Pseudoaneurysm > Table of Contents > Section 12 - Arterial > Thoracic Aorta and Great Vessels > Chronic Post-Traumatic Pseudoaneurysm Chronic Post-Traumatic Pseudoaneurysm Santiago Martínez-Jiménez, MD Key Facts Terminology Traumatic disruption of aortic wall that goes undiagnosed in acute setting Chronic traumatic aortic injury (CTAI) Imaging Radiography AP window mass Curvilinear calcification typically lining caudad portion of aortic arch 961

Diagnostic Imaging Cardiovascular Rightward tracheal deviation CTA Saccular dilatation at isthmus arising from anterior aspect of aortic arch Curvilinear mural calcification along saccular dilatation Ancillary findings of remote trauma Healed rib, clavicular or scapular fractures Thoracic vertebral body wedge fractures Top Differential Diagnoses Nontraumatic aortic aneurysm In atherosclerosis, calcification often lines superoexternal portion of aortic arch and other locations Mycotic aneurysm often lacks calcifications Penetrating aortic ulcer is not common at isthmus; often with extensive atherosclerosis Mediastinal mass Ductus aneurysm Often indistinguishable from CTAI on imaging Clinical Issues Asymptomatic; incidental finding on imaging Unknown incidence 1/3 of CTAI may rupture and cause death if untreated Preferred treatment: Open surgical repair Alternative treatment: Endovascular repair

(Left) PA radiograph of the chest in a young asymptomatic patient with chronic traumatic aortic injury (CTAI) and right diaphragmatic hernia shows curvilinear calcification lining the caudad part of the aortic arch . There is elevation of the right hemidiaphragm form chronic undiagnosed right diaphragmatic hernia . Note remote rib fractures . (Right) Lateral radiograph of the chest in the same patient shows aortic bulging with intrinsic mural calcification at the isthmus.

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(Left) Axial chest CTA in the same patient demonstrates saccular isthmic aortic dilatation with some mural calcifications in continuity with the aortic lumen. (Right) Axial chest CTA in the same patient reveals extensive calcifications along the wall of the pseudoaneurysm. This constitutes the most common imaging appearance of chronic traumatic aortic injury. P.12:31

TERMINOLOGY Synonyms Chronic traumatic aortic injury (CTAI) Late or unsuspected post-traumatic pseudoaneurysm Definitions Traumatic disruption of aortic wall that remains undiagnosed in acute setting IMAGING General Features Best diagnostic clue Saccular aneurysm with wall calcification at level of aortic isthmus Location Anterior surface of aortic isthmus Morphology Saccular, acute margins with aorta Imaging Recommendations Best imaging tool CTA Protocol advice Use of multiplanar reformations on CTA or MRA may be helpful Radiographic Findings Radiography Frontal projection AP window mass Curvilinear calcification typically lining the distal portion aortic arch/proximal descending aorta Rightward tracheal deviation Lateral projection Curvilinear calcified convexity (mass) at aortic isthmus CT Findings CTA Saccular dilatation at isthmus arising from anterior aspect of aortic arch Acute margins with aorta, narrow ostium Curvilinear mural calcification at saccular dilatation May contain low-density thrombus May cause extrinsic compression of left main bronchus 963

Diagnostic Imaging Cardiovascular Remainder of aorta may be normal Ancillary findings of remote trauma Healed rib, clavicular, or scapular fractures Thoracic vertebral body wedge fractures Elevation of hemidiaphragms; traumatic diaphragmatic hernia must be excluded MR Findings MRA Contrast-filled saccular dilatation at aortic isthmus in continuity with aorta Intraluminal thrombus appears hypointense Black blood and white blood (e.g., SSFP) are as accurate as CTA Used when CTA is contraindicated Angiographic Findings Rarely required (often part of endovascular treatment) DIFFERENTIAL DIAGNOSIS Nontraumatic Aortic Aneurysm May be secondary to atherosclerosis, infection (i.e., mycotic), or penetrating aortic ulcer (PAU) In atherosclerosis, calcification often lines superoexternal portion of aortic arch and is also found in other locations Mycotic aneurysm often lacks calcifications PAU is uncommon at isthmus and often has extensive atherosclerosis There is history of remote trauma in CTAI, and calcifications are limited to saccular dilatation May be impossible to differentiate from pseudoaneurysm (i.e., acute traumatic aortic injury [ATAI] or CTAI) on imaging Mediastinal Mass e.g., lung cancer, bronchogenic cyst CT with contrast is often diagnostic Ductus Aneurysm May be difficult to distinguish from CTAI on imaging Smooth obtuse margins, wide ostium PATHOLOGY General Features Etiology Post-traumatic Associated abnormalities Osseous fractures Diaphragmatic hernia CLINICAL ISSUES Presentation Most common signs/symptoms Asymptomatic; incidental finding on imaging Demographics Epidemiology Unknown incidence Small minority of ATAI cases remain undiagnosed and may become CTAI Natural History & Prognosis 1/3 of CTAI rupture and cause death if untreated May rupture even years after acute injury Treatment Preferred treatment: Open surgical repair Alternative treatment: Endovascular repair SELECTED REFERENCES 1. Pozek I et al: Chronic posttraumatic pseudoaneurysm of the thoracic aorta. Curr Probl Diagn Radiol. 41(4):126-7, 2012 2. Marcu CB et al: Unsuspected chronic traumatic aortic pseudoaneurysm—what to do about it. Late post-traumatic aortic pseudoaneurysm. Can J Cardiol. 24(2):143-4, 2008 3. Bacharach JM et al: Chronic traumatic thoracic aneurysm: report of two cases with the question of timing for surgical intervention. J Vasc Surg. 17(4):780-3, 1993 4. Heystraten FM et al: Chronic posttraumatic aneurysm of the thoracic aorta: surgically correctable occult threat. AJR Am J Roentgenol. 146(2):303-8, 1986 964

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Image Gallery

(Left) Oblique sagittal chest CTA in an asymptomatic patient with chronic traumatic aortic injury and right diaphragmatic hernia shows a well-defined aortic pseudoaneurysm at the aortic isthmus. Note characteristic sudden change in caliber of the aorta distally, a common finding. (Right) Coronal chest CTA in the same patient demonstrates characteristic right diaphragmatic rupture with the “hourglass” sign of the liver and a frank hemidiaphragmatic defect .

(Left) Posterior sagittal chest 3D reformation in the same patient demonstrates the aortic pseudoaneurysm and its relationship with the pulmonary artery and the left atrium. 3D reformations may be helpful for better anatomic understanding and appropriate surgical planning. (Right) PA chest radiograph in an asymptomatic patient with chronic traumatic aortic injury and a pseudoaneurysm shows curvilinear calcifications along the inferior aspect of the aortic arch.

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(Left) Axial chest CTA in the same patient demonstrates well-marginated saccular dilatation of the aorta at the level of the isthmus. (Right) Oblique sagittal reformation chest CTA in the same patient shows an isthmic pseudoaneurysm with intrinsic curvilinear wall calcifications. A ductus aneurysm can be difficult to differentiate from a chronic traumatic aortic injury on imaging. However, they both have similar clinical and prognostic considerations as well as treatment. P.12:33

(Left) PA chest radiograph in an asymptomatic patient with chronic traumatic aortic injury shows mild widening of the mediastinum. (Right) Lateral chest radiograph in the same patient demonstrates that, given a lack of significant amount of wall calcification, the abnormality (i.e., the pseudoaneurysm) is difficult to appreciate on chest radiography. While surgery has been historically the treatment of choice of CTAI, there are some successful reports of conservative treatment.

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(Left) Axial NECT in the same patient reveals contour abnormality at the level of the aortic isthmus. (Right) Axial CTA in the same patient shows a saccular aneurysm at the level of the aortic isthmus. In general, some clues that support the diagnosis include a positive clinical history of significant trauma, lack of atherosclerotic changes elsewhere, and location of abnormalities at the level of the aortic isthmus.

(Left) Oblique CTA “candy cane” reformations in the same patient make the identification of the saccular aneurysm easier. The lack of mediastinal hemorrhage and other associated injuries supports the chronicity of the finding. (Right) Oblique sagittal DSA in a patient with chronic traumatic aortic injury shows contrast filling the saccular outpouching . The CT and angiographic features, along with the patient's history, are consistent with a posttraumatic thoracic aortic pseudoaneurysm.

Aortic Intramural Hematoma > Table of Contents > Section 12 - Arterial > Thoracic Aorta and Great Vessels > Aortic Intramural Hematoma Aortic Intramural Hematoma Santiago Martínez-Jiménez, MD Key Facts Terminology Acute aortic syndrome comprises aortic dissection (AD), incomplete aortic dissection, penetrating aortic ulcer (PAU), and intramural hematoma (IMH) IMH (or class 2 AD) Aortic media hemorrhage from spontaneous vasa vasorum rhexis or, occasionally, trauma Absent or very small entrance tear and absent reentrance tear PAU (or class 4 AD) Ulcerated atherosclerotic lesion that penetrates internal elastic lamina 967

Diagnostic Imaging Cardiovascular Variable amounts of intramural hemorrhage Imaging CTA: Concentric/crescentic aortic wall thickening; aortic rupture with hemopericardium, hemothorax, and mediastinal hemorrhage NECT: Concentric/crescentic aortic hyperdensity Top Differential Diagnoses Aortitis (Takayasu and giant cell arteritis) Parietal thickening simulates IMH on CTA; however, not hyperdense on NECT Mural enhancement on MR with contrast Pathology Stanford classification Type A (˜ 60%): Ascending aorta ± descending aorta Type B (˜ 40%): Descending aorta Clinical Issues Abrupt onset of severe chest or back pain Hypertension Evolutive patterns: AD, aortic rupture, resolution Treatment Type A: Surgical treatment Type B: Medical treatment and close follow-up

(Left) Frontal radiograph of the chest in a patient with type B intramural hematoma (IMH) is normal. Chest radiography is always obtained in patients with acute aortic syndrome as it is helpful to determine other causes of chest pain, such as airspace disease, pneumothorax, etc. (Right) Axial NECT in the same patient shows crescentic hyperdensity along the descending thoracic aorta. This is a characteristic feature that allows differentiation from arteritis, which also exhibits mural thickening on CTA.

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(Left) Axial CTA in the same patient shows crescentic thickening along the descending thoracic aorta. (Right) Sagittal oblique CTA in the same patient shows IMH extending from the distal aortic arch into the descending thoracic aorta. Note mild aortic luminal narrowing of the affected area when compared with the normal descending aorta. This latter feature may be helpful when differentiating IMH from incomplete dissection with subadventitial hemorrhage. P.12:35

TERMINOLOGY Definitions Acute aortic syndrome comprises aortic dissection (AD), incomplete aortic dissection (ID), penetrating aortic ulcer (PAU), and intramural hematoma (IMH) IMH (or class 2 AD) Aortic media hemorrhage from spontaneous vasa vasorum rhexis or, occasionally, trauma Absent or very small entrance tear and absent reentrance tear PAU (or class 4 AD) Ulcerated atherosclerotic lesion that penetrates internal elastic lamina IMAGING General Features Best diagnostic clue Concentric or crescentic aortic hyperdensity on NECT CT Findings NECT Concentric or crescentic aortic wall hyperdensity CTA Concentric or crescentic aortic wall thickening ↓ luminal aortic diameter along IMH extension Classically without discrete intimomedial flap or detectable fenestration Discrete intimomedial flap represents coexistent AD Common ancillary findings: Pericardial effusion and periaortic hematoma (↑ risk of rupture) Aortic rupture with hemopericardium, hemothorax, mediastinal hemorrhage, or frank extravasation Contrast collections beyond internal aortic margin PAU Outpouching of contrast extending beyond expected external aortic margin Focal atherosclerotic irregular intima Ulcer-like projections (ULP) Outpouching of contrast with wide intimal opening Differentiation from PAU: Lack of irregular intima; may be indistinguishable Intramural blood pool (IBP) Pool of contrast with small intimal orifice &/or connection with intercostal or lumbar artery 969

Diagnostic Imaging Cardiovascular More common when thickness of IMH is > 10 mm MR Findings T1WI Acute IMH is isointense Subacute IMH is hyperintense T2WI Acute IMH is hyperintense After 1-5 days, IMH has lower intensity T1WI C+ Lack of enhancement MRA Efficiently shows PAU, ULP, and IBP Phase-contrast MR Lack of flow unless coexistent AD DIFFERENTIAL DIAGNOSIS Aortitis (Takayasu and Giant Cell Arteritis) Inflammation of large and medium-sized arteries Scattered areas of stenosis ± aneurysm Parietal thickening simulates IMH on CTA However, not hyperdense on NECT Mural enhancement on MR with contrast PATHOLOGY General Features Etiology Vasa vasorum rhexis PAU Staging, Grading, & Classification Stanford classification Type A (˜ 60%): Ascending aorta ± descending aorta Type B (˜ 40%): Descending aorta CLINICAL ISSUES Presentation Most common signs/symptoms Abrupt onset of severe chest or back pain Hypertension Natural History & Prognosis Evolutive patterns Evolution or coexistence with AD (28-47%) Spontaneous resolution (˜ 10%) Aortic rupture (20-45%) Stability over time (rare) Predictors of mortality Involvement of ascending aorta Maximum aortic diameter (≥ 50 mm) Mortality of type A IMH with only medical treatment is ˜ 40% ULP ↑ incidence of disease progression (especially when ULP > 20 mm) IBP Not considered at ↑ risk for disease progression Often resolves over time Seen on initial CT, often with new IBPs on follow-up This is associated with development of ULPs Treatment Type A IMH: Surgical treatment Type B IMH: Medical treatment and close follow-up SELECTED REFERENCES 1. Akin I et al: Penetrating aortic ulcer, intramural hematoma, acute aortic syndrome: when to do what. J Cardiovasc Surg (Torino). 53(1 Suppl 1):83-90, 2012

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Diagnostic Imaging Cardiovascular 2. Harris KM et al: Acute aortic intramural hematoma: an analysis from the International Registry of Acute Aortic Dissection. Circulation. 126(11 Suppl 1):S91-6, 2012 3. Wu MT et al: Intramural blood pools accompanying aortic intramural hematoma: CT appearance and natural course. Radiology. 258(3):705-13, 2011 P.12:36

Image Gallery

(Left) Axial black blood MR in a patient with type B IMH shows the presence of hyperintense crescentic IMH along the descending thoracic aorta. This intensity behavior is consistent with acute hemorrhage. (Right) Axial SSFP MR in the same patient shows that the IMH is iso- to slightly hyperintense when compared with adjacent muscles. MR is as efficient as CT in determining and characterizing the presence of IMH and may be used when CT is unavailable or contraindicated.

(Left) Whereas prior CT (not shown) in a patient with type B IMH did not show IBP or ULP, follow-up axial CTA of the chest demonstrates IBP with small intimal orifice along the descending thoracic aorta. This is a key feature to differentiate it from ULP or PAU. (Right) Oblique sagittal MRA in the same patient shows IBP with a narrow neck along the descending thoracic aorta. As opposed to ULP, IBP is not associated with a worse prognosis and, not infrequently, resolves over time.

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(Left) Axial CTA of the chest in a patient with IMH associated with PAU shows a large PAU with a broad neck along the distal thoracic aorta, likely the primary cause of the IMH. Note also a ULP along the aortic arch. (Right) Sagittal oblique CTA 3D reformation in the same patient demonstrates both the PAU and the ULP . Differentiation between these conditions seen with IMH is important as they have different prognostic implications. P.12:37

(Left) Axial chest NECT in a patient with chest pain and type A IMH shows crescentic hyperdensity , consistent with IMH along the ascending and descending thoracic aorta. (Right) Axial chest CTA in the same patient shows concentric thickening along the ascending and descending thoracic aorta as well as a small IBP along the descending thoracic aorta . Note small pericardial and bilateral pleural effusions, which are common nonspecific findings.

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(Left) Axial chest NECT in a patient with type B IMH treated clinically shows the classic crescentic aortic wall hyperdensity . CTA demonstrates the classic crescentic wall thickening . (Right) Axial NECT and CTA in the same patient show complete resolution of the IMH. IMH can resolve, remain stable, or progress to a variety of complications, including aortic dissection and rupture. CT remains the best follow-up tool for patients with type B IMH.

(Left) Axial chest NECT and CTA in a patient with type A IMH show a coexistent type B aortic dissection . (Right) Axial chest NECT and CTA in a patient with incomplete dissection show crescentic hyperdensity and thickening along the ascending aorta, findings identical to those seen in IMH. Note discrete bulging along the posterior ascending thoracic aorta. This finding is the key element that suggests the diagnosis of incomplete aortic dissection.

Penetrating Atherosclerotic Ulcer > Table of Contents > Section 12 - Arterial > Thoracic Aorta and Great Vessels > Penetrating Atherosclerotic Ulcer Penetrating Atherosclerotic Ulcer Santiago Martínez-Jiménez, MD Key Facts Terminology Ulceration of atherosclerotic plaque that penetrates internal elastic lamina into the media with variable amount of intramural hematoma (IMH) Imaging NECT: Concentric or crescentic hyperdense IMH CTA: Contrast outpouching extending beyond aortic wall confines 973

Diagnostic Imaging Cardiovascular IMH: Concentric or crescentic aortic wall thickening MR: Similar sensitivity and findings to CTA Top Differential Diagnoses Takayasu and giant cell arteritis Infectious (mycotic) pseudoaneurysm Traumatic aortic injury Pathology Stanford classification for aortic dissection Type A: Ascending ± arch/descending aorta Type B: Ascending not involved (only descending ± arch) Variable IMH from erosion of vasa vasorum Clinical Issues Chest pain Patients commonly have hypertension, hyperlipidemia May be asymptomatic 7th decade; M > F Penetrating aortic ulcer (PAU) represents 2-10% of all acute aortic syndromes Treatment Endovascular therapy: Treatment choice when feasible in symptomatic patients Surgery: Endovascular procedure not feasible, hemodynamical instability, or PAU type A

(Left) PA chest radiograph in a patient with penetrating aortic ulcer (PAU) at the aortic arch shows a mediastinal mass lateral to the aortic arch from associated hematoma. (Right) Oblique sagittal CTA of the chest in the same patient shows extensive atherosclerosis of the aorta with a small ulcer and a large focal mural hematoma . PAUs are commonly associated with a variable degree of intramural hematoma that may be focal (as in this case) or diffuse.

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(Left) Axial chest CTA in a patient with ulcerated atherosclerotic plaque shows that, as opposed to PAU, the ulcerated plaque does not extend beyond the expected aortic wall margin. (Right) Axial chest CTA in a patient with PAU at the aortic arch shows a large contrast collection extending beyond the expected aortic margin. Note also intraluminal thrombus . Although PAUs are more commonly located in the descending thoracic aorta, they can occur anywhere along the aorta. P.12:39

TERMINOLOGY Definitions Ulceration of atherosclerotic plaque that penetrates internal elastic lamina into the media with variable amount of intramural hematoma (IMH) Acute aortic syndrome (AAS) comprises aortic dissection (AD), incomplete aortic dissection (ID), penetrating aortic ulcer (PAU), and IMH IMAGING General Features Best diagnostic clue Contrast outpouching extending beyond aortic wall confines, often in setting of atherosclerosis Location More common along descending thoracic aorta Radiographic Findings Chest radiography is insensitive and often normal CT Findings NECT Calcified atherosclerotic plaques Focal aortic lobulation Segmental concentric or crescentic hyperdense IMH CTA Ulcer: Contrast outpouching extending beyond aortic wall confines Differentiation from ulcerated atherosclerotic plaque: Not extending beyond expected aortic wall confines and not associated with mural hemorrhage Differentiation from ulcer-like projection Outpouching of contrast has wide intimal opening Lack of irregular intima; may be indistinguishable Differentiation from intramural blood pool Pool of contrast with small intimal orifice &/or connection with intercostal or lumbar artery More common when thickness of IMH > 10 mm Focal soft tissue (i.e., hemorrhage) adjacent to ulcer (i.e., contained rupture or pseudoaneurysm) IMH appears as concentric or crescentic aortic wall thickening Concomitant descending aortic aneurysms (common) 975

Diagnostic Imaging Cardiovascular Complications AD: Intimomedial flap Short and localized intimomedial flap Thick, calcified intimomedial flap True lumen is usually smaller than false lumen Retrograde direction Contained aortic rupture: Focal aortic wall hematoma Aortic rupture: Mediastinal hematoma, hemothorax MR Findings MRA Similarly sensitive to CTA, similar findings Imaging Recommendations Protocol advice Obtain NECT before CTA to help identify IMH DIFFERENTIAL DIAGNOSIS Takayasu and Giant Cell Arteritis Absent concentric or crescentic wall hyperdensity Aortic wall enhancement after contrast-enhanced MR Mycotic Pseudoaneurysm Infectious clinical picture and lack of atherosclerosis PATHOLOGY General Features Etiology Atherosclerotic lesion with disruption of internal elastic lamina of aortic wall Staging, Grading, & Classification Stanford classification (for aortic dissection) Type A: Ascending ± arch/descending aorta Type B: Descending aorta &/or arch Gross Pathologic & Surgical Features Variable presence/degree of IMH from erosion of vasa vasorum CLINICAL ISSUES Presentation Most common signs/symptoms Chest pain Demographics Age Late in life; most prevalent in 7th decade Gender M>F Epidemiology PAU represents 2-10% of all AAS Risk factors: Hypertension, tobacco use, coronary artery disease, COPD, and renal insufficiency Natural History & Prognosis Evolution of PAU May remain stable May progress to AD Aortic rupture (relatively common) Aortic remodeling (i.e., saccular aneurysm) ↑ risk of aortic rupture: ↑ pleural effusion and both maximum PAU diameter (21.1 mm ± 8.0 mm) and maximum PAU depth (13.7 ± 4.2 mm) Treatment Endovascular therapy: Treatment choice when feasible in symptomatic patients Surgery: Endovascular procedure not feasible, hemodynamical instability, or PAU type A SELECTED REFERENCES 1. Akin I et al: Penetrating aortic ulcer, intramural hematoma, acute aortic syndrome: when to do what. J Cardiovasc Surg (Torino). 53(1 Suppl 1):83-90, 2012 2. Bischoff MS et al: Penetrating aortic ulcer: defining risks and therapeutic strategies. Herz. 36(6):498-504, 2011 3. Vilacosta I et al: Acute aortic syndrome: a new look at an old conundrum. Postgrad Med J. 86(1011):52-61, 2010 P.12:40 976

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Image Gallery

(Left) Axial NECT of the chest in a patient with PAU at the aortic arch with aortic rupture shows a mediastinal hematoma indicating rupture. (Right) Axial CTA of the chest in the same patient shows the large ulceration along the anterior proximal aortic arch with surrounding hemorrhage . Aortic rupture is the most feared complication of PAU, often resulting in death before imaging, and warrants immediate intervention.

(Left) Axial CTA of the chest in the same patient shows a large ulceration along the anterior proximal aortic arch with surrounding hemorrhage and extensive atherosclerosis . (Right) Oblique sagittal reformation CTA of the chest in the same patient well depicts the ulceration and large pseudoaneurysm along the proximal arch.

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(Left) Oblique sagittal 3D reformation CTA of the chest in the same patient shows a large pseudoaneurysm . Note the extrinsic compression of the proximal left carotid artery . (Right) Axial CTA in a patient with PAU and aneurysm of the descending thoracic aorta with aortic dissection (AD) shows an ulceration with conspicuous and thick intimomedial flap-like margins in a location not classic for AD. These are helpful features to differentiate AD arising from PAU from classic AD. P.12:41

(Left) Axial chest CTA in a patient with PAU along the descending thoracic aorta shows a contrast collection extending beyond the expected aortic margin. Note surrounding soft tissue, consistent with focal intramural hematoma. (Right) Sagittal CTA in the same patient shows a well-defined PAU . Note adjacent atherosclerotic plaques . In contrast to mycotic pseudoaneurysm or traumatic aortic injury, PAU is invariably associated with atherosclerosis.

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(Left) Axial NECT of the chest in a patient with intramural hematoma (IMH) secondary to PAU shows crescentic hyperdensity along the descending aorta, consistent with IMH. NECT is of importance in the setting of PAU as it helps to differentiate from arteritis, which is not hyperdense. (Right) Sagittal CTA of the chest in a patient with IMH secondary to PAU shows a large relatively shallow ulceration extending beyond the expected aortic margin. Note also the aortic wall thickening from IMH.

(Left) Axial NECT & CTA in a patient with contained rupture of descending aortic PAU shows retrocrural hemorrhage and atherosclerosis with contrast collection extending beyond the expected aortic margin. (Right) Axial CTA of the chest in a patient with PAU before and after treatment shows a PAU along the descending thoracic aorta. Note exclusion of PAU after placement of endovascular stent. Endovascular therapy has arisen as the treatment of choice whenever feasible.

Aortic Dissection Key Facts Terminology Blood enters media of aortic wall through intimal defect and splits wall longitudinally Imaging 2 distinct lumina (false and true) with an interposed intimal flap False lumen: Larger cross-sectional area, “beak” sign, “cobweb” sign, thrombosis, and delayed enhancement True lumen: Continuity with undissected portion of aorta and smaller cross-sectional area Radiograph: Progressive aortic enlargement, widened mediastinum (> 8 cm), and abnormal (blunted) aortic knob CT scan: Highly accurate 979

Diagnostic Imaging Cardiovascular Slightly less accurate for ascending aorta unless ECG-gated study MR: Well-suited for follow-up Transesophageal echocardiography: Operator dependent and with limited field of view Top Differential Diagnoses Thrombosed aneurysm Aortic wall hematoma Syndromes associated with aortic dissection Pathology Media degeneration associated with many diseases, syphilitic aortitis, crack cocaine use, and iatrogenic Tear in the intimal layer leading to formation and propagation of subintimal hematoma Clinical Issues Type A: Surgery due to involvement of aortic root Type B: Medical control of hypertension is standard Percutaneous therapy for complicated nonsurgical patients with type B dissections

(Left) Frontal chest radiograph shows subtle abnormal contour of the ascending aorta suggestive of ascending aortic aneurysm , but the finding is nonspecific. The descending aorta is tortuous, which can be seen in systemic hypertension. (Right) Frontal radiograph in the same patient presenting few months latter with acute chest pain shows increased contour and abnormal widening of the mediastinum suggestive of aortic dissection .

(Left) Axial CTA image through the thorax in a patient with Stanford type A dissection shows a nearly circumferential dissection flap involving the aortic root and descending aorta. Note small true lumen in the ascending aorta. The intimal flap can be quite mobile on gated cine imaging. (Right) Axial CTA image at the level of arch in the same patient shows extension of the dissection flap into the right brachiocephalic artery . Note displaced intimal calcification in descending aorta . 980

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TERMINOLOGY Abbreviations Aortic dissection (AoD) Definitions Blood enters media of aortic wall through intimal defect and splits wall longitudinally Stanford classification Type A (60%): Involves ascending aorta, ± descending aorta Surgical treatment Type B (40%): Excludes ascending aorta; involves descending aorta &/or aortic arch Medical management DeBakey classification Type I: Involves ascending aorta, aortic arch, and descending aorta Type II: Involves ascending aorta Type III: Involves descending aorta distal to left subclavian artery IMAGING General Features Best diagnostic clue 2 distinct lumina (false and true) with interposed intimal flap giving an appearance of “double barrel” aorta Displacement of intimal calcification or compression or distortion of aortic lumen Location Type A: 90% within 10 cm of aortic valve Includes type I and type II Type B: Distal to origin of brachiocephalic trunk Type III: Distal to left subclavian artery Additional imaging should evaluate involvement of great vessels and celiac, renal artery, superior mesenteric, and iliac arteries Radiographic Findings Radiography Widened mediastinum (> 8 cm) Abnormal (blunted) aortic knob in 66% May display ring sign: Displacement of aorta > 5 mm past calcified aortic intima Left apical cap, tracheal deviation, depression of left main stem bronchus, esophageal deviation, loss of paratracheal stripe, pericardial effusion, and hemothorax Progressive aortic enlargement on serial images Enlarged arch is not specific for diagnosis; usually results from hypertension or atherosclerosis CT Findings NECT Widening of aorta, irregularity of aortic wall, and intramural or periaortic acute thrombus Hyperattenuating mediastinal, pericardial, or pleural fluid (blood) Internally displaced intimal calcification CECT ECG gating allows better delineation of proximal extent of intimal flap in relation to aortic valve and coronary ostia Intimal flap separates true and false lumina True lumen is indicated by continuity with aortic valve Usually has smaller cross-sectional area than false lumen False lumen wedges around true lumen, resulting in “beak” sign May have collagenous media remnants (“cobweb” sign) May thrombose Delayed flow in false lumen Compression of true lumen by expanding false lumen Intraluminal thrombus if persistent nonenhancement on delayed-phase CT Complete thrombosis and reduced flow in false lumen decreases risk of subsequent aortic dilatation Important: Exclude retrograde dissection into aortic arch 981

Diagnostic Imaging Cardiovascular Observed in 27% of type B dissections Associated with higher mortality rates (43%) May show pericardial effusion and infradiaphragmatic ischemic complications MR Findings T1WI Used for evaluation of abdominal arterial involvement and monitoring of progression of dissection and aneurysm formation Signal intensity within false lumen is variable Depends on blood flow; presence, age, and composition of thrombus; and pulse sequence May show site of intimal tear, type and extent of dissection, and presence of aortic insufficiency False lumen flow is slower Flap may be outlined by signal void on 1 side and an increased intraluminal signal on other Slow flow in false lumen may resemble thrombus Identification of aortoannular ectasia T2* GRE Intimal flap: Low or medium signal intensity between 2 high signal intensity blood-containing channels Reentry site: Depicted by low signal intensity turbulent flow between true and false lumina False lumen with slow blood flow &/or thrombotic material: Medium to low signal intensity Echocardiographic Findings Echocardiogram Transesophageal echocardiography (TEE) Most important finding: Presence of an undulating intimal flap within aortic lumen May identify entry site, presence of false lumen thrombus, abnormal flow characteristics, involvement of coronary and arch vessels, pericardial effusion, and aortic valve regurgitation False positives: May occur if calcified aorta mimics intimal flap Color Doppler Identifies flow in false lumen, site of intimal tear, and presence or absence of aortic insufficiency Angiographic Findings Conventional False lumen is visualized in 87%, intimal flap in 70%, and site of intimal tear in 56% P.12:44

May show site of intimal tears, aortic valve regurgitation, coronary artery involvement, and filling of branch vessels Indirect signs of AoD: Compression of true lumen by false lumen and abnormal appearance of branch vessel origins False-negative angiogram may occur due to thrombosis of false lumen Imaging Recommendations CT scan: Highly accurate Slightly less accurate for ascending AoD Gating or triggering overcomes risk of false positives in aortic root MR: Better suited for follow-up TEE: Possible in most patients, including unstable Highly dependent on operator's experience Not used if esophageal varicosities or stenosis Limited view of dissection DIFFERENTIAL DIAGNOSIS Thrombosed Aneurysm Large aorta and aortic lumen size Intramural Hematoma Hemorrhage within wall with no identifiable intimal flap or false lumen Caused by bleeding from vasa vasorum into media Penetrating Aortic Ulcer Perforation of aortic wall in region of ulcerated atherosclerotic plaque Most common in descending aorta May progress to dissection Syndromes and Conditions Associated With Aortic Dissection 982

Diagnostic Imaging Cardiovascular Marfan syndrome, Ehlers-Danlos syndrome, bicuspid aortic valve PATHOLOGY General Features Etiology Medial degeneration is associated with many diseases that predispose to dissection Hypertension (70%), atherosclerosis Structural collagen disorder (Marfan or Ehlers-Danlos syndrome) Congenital disease (aortic coarctation; bicuspid or unicuspid valve), pregnancy, collagen vascular disease (rare) Pregnancy; collagen vascular disease (rare) Syphilitic aortitis, crack cocaine use, and iatrogenic (catheter angiography, cardiac surgery, valve replacements) Dissections almost exclusively originate in thoracic aorta and secondarily involve abdominal aorta Gross Pathologic & Surgical Features Intimal tear leading to formation/propagation of subintimal hematoma 5-10% are without intimal tear; dissection is attributed to rupture of aortic vasa vasorum Diseases that weaken aortic wall predispose to AoD CLINICAL ISSUES Presentation Most common signs/symptoms Sudden onset of ripping or tearing chest pain Anterior chest pain: Ascending AoD Neck or jaw pain: Aortic arch dissection Back tearing or ripping pain: Descending AoD Myocardial infarction 50% of AoD: Women < 40 years, related to pregnancy Sudden onset of aortic insufficiency, neurologic deficits in 20% of cases, and ischemic extremity Demographics Age 75% occur in 40-70 years; peak at 50-65 years Gender M:F = 3:1 Ethnicity African Americans > Caucasians > Asians Natural History & Prognosis Rupture of aorta Dissection into pericardium with cardiac tamponade Occlusion of coronary or supraaortic vessels Severe aortic insufficiency with acute heart failure 21% of patients die before hospital admission If untreated, 33% die within 24 hours; 50% within 48 hours < 10% of untreated patients with type A live 1 year Acute AoD: Diagnosed within 14 days Chronic AoD: Diagnosed after 14 days Treatment Type A: Surgery due to involvement of aortic root Type B: Medical control of hypertension is standard Surgery in complicated cases Mesenteric, renal, extremity ischemia Rupture, aneurysmal enlargement of false lumen Percutaneous therapy for complicated nonsurgical patients with type B dissections Aortic stent graft, fenestration of luminal flap Type A mortality: 60% of medically treated; 30% of surgically treated Type B mortality: 10% of medically treated 10%; 30% of surgically treated DIAGNOSTIC CHECKLIST Consider AoD in patient with acute chest pain ECG-gated CTA in acute AoD; MRA for follow-up Image Interpretation Pearls 983

Diagnostic Imaging Cardiovascular Identify origin of intimal flap, extent of dissection, and origin of aortic branches from true or false lumen SELECTED REFERENCES 1. Di Eusanio M et al: Clinical presentation, management, and short-term outcome of patients with type A acute dissection complicated by mesenteric malperfusion: observations from the International Registry of Acute Aortic Dissection. J Thorac Cardiovasc Surg. 145(2):385-390, 2013 P.12:45

Image Gallery

(Left) DeBakey type I and Stanford class A include dissections that involve the ascending aorta. DeBakey type II is confined to the ascending aorta, and type I extends beyond. DeBakey type III dissections are confined to the descending aorta. Stanford class B includes all dissections not involving the ascending aorta (involving arch &/or descending aorta). (Right) “Candy cane” and axial CTA views show type A dissection with partially thrombosed false lumen .

(Left) Axial and VR CTA shows Stanford type B aortic dissection involving thoracic and abdominal aorta. Also note infrarenal abdominal aortic aneurysm . (Right) Transthoracic echocardiogram shows ascending aortic dissection with dissection flap (white interface ) separating true and false lumina. Most of the false lumen is hyperechoic, suggesting thrombosis . The small anechoic portion corresponds to a patent false lumen .

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(Left) Axial CECT shows acute type A aortic dissection with flap that is convex toward false lumen . Note that a beak sign is present in the false lumen. The appearance of a beak sign is attributed to the higher systolic pressure in the true lumen. (Right) Axial MRA shows chronic type B aortic dissection with partial thrombosis of the false lumen (hypointense area) . Compared with the false lumen, the true lumen is relatively small . Note the perfused portion of the false lumen . P.12:46

(Left) Axial NECT, CTA, and MR are from a patient with type B aortic dissection. The aortic dissection is not seen on NECT acquisition. Axial unenhanced MR images show aortic dissection on HASTE (dark blood) and SSFP (bright blood) imaging, an advantage over NECT. (Right) Axial NECT and CTA show chronic descending thoracic aortic dissection with a flat dissection flap. Outer wall calcification and thrombus are present in the false lumen .

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Diagnostic Imaging Cardiovascular

(Left) Axial CECT show a high-attenuation pericardial effusion , consistent with a hemopericardium, as well as bilateral trace pleural effusions . The dissection flap is clearly visible in the descending thoracic aorta . (Right) Axial CTA shows abdominal aortic dissection with Mercedes-Benz sign relating to a 3-channel dissection resulting in 2 false lumina . One of the 2 intimal flaps extends to the origin of the right renal artery .

(Left) Axial and oblique CTA show a type A aortic dissection involving the right coronary artery ostium in a patient status post percutaneous aortic valve implantation/replacement (TAVI/R). (Right) Axial CTA shows an abdominal aortic dissection . Note that the dissection flap does extend into the superior mesenteric artery , which remains well perfused. P.12:47

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(Left) Axial CTA shows partial eccentric thrombosis of the false lumen in a chronic aortic dissection. The celiac artery arises from the false lumen and is thrombosed. (Right) Oblique MIP CTA shows dissection of the descending thoracic and abdominal aorta. Note main and accessory renal arteries arising from the partially thrombosed false lumen and a subtotal infarct of the left kidney. Main and accessory renal arteries demonstrate partial flow.

(Left) Axial CTA image shows a dissection flap extending into the left common carotid artery . The true lumen is smaller and enhances more than the false lumen . (Right) Axial (left) and coronal (right) CTA images show atypical appearance of an aortic dissection involving the entire intima of the thoracic aorta circumferentially. This phenomenon may subsequently lead to intimointimal intussusception.

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Diagnostic Imaging Cardiovascular

(Left) Early-phase catheter angiography shows an opacified, compressed true lumen in the initial phase of the contrast injection. Multiple intercostal arteries arise from this lumen, but no other aortic branches are seen. (Right) Later phase of the same injection shows the less dense false lumen . The right renal artery , the superior mesenteric artery branches , and a right nephrogram are now evident . The linear density between the 2 lumina is the intimal flap.

Takayasu Arteritis Key Facts Terminology Pulseless disease Chronic granulomatous vasculitis of large vessels Imaging Best diagnostic clue: Wall thickening of large vessels Thoracic aorta and branches Pulmonary artery involvement is less common NECT: Aortic wall thickening CECT: Aortic wall thickening and enhancement Stenosis, occlusion, aneurysm MRA: Aortic narrowing, dilatation Angiography: 4 types classified by location PET/CT is used for treatment monitoring Complications Stenosis > occlusion Aneurysm Dissection Top Differential Diagnoses Giant cell arteritis Aortic coarctation Pathology Autoimmune etiology is suspected Specific types of human leukocyte antigen are common among patients Clinical Issues Disease stages Early or prepulseless phase Vascular inflammatory phase Late quiescent occlusive or pulseless phase Triphasic disease in minority of patients F:M = 8:1 Heart failure is most common cause of death Treatment 988

Diagnostic Imaging Cardiovascular Corticosteroids, angioplasty, surgical bypass

(Left) Axial CECT of a patient with Takayasu arteritis shows marked thickening of the wall of the ascending thoracic aorta . The thoracic aorta and its branches, particularly the left subclavian artery, are the most commonly affected vessels in Takayasu arteritis. (Right) Axial T1WI MR of a different patient with Takayasu arteritis demonstrates thickening of the wall of the ascending thoracic aorta and the pulmonary trunk . Vessel stenosis, occlusion, and aneurysm formation may complicate cases of Takayasu arteritis.

(Left) Axial fused PET/CT of a patient with active Takayasu arteritis demonstrates intense FDG uptake within the mediastinum adjacent to the aortic arch in a region of soft tissue attenuation that was present on the localization CT. (Right) Axial fused PET/CT of the same patient shows intense FDG uptake within the mediastinum adjacent to the ascending aorta and pulmonary arteries . FDG uptake may be low grade to intense in Takayasu arteritis, and PET/CT is an effective way of monitoring treatment response. P.12:49

TERMINOLOGY Synonyms Pulseless disease Definitions Chronic granulomatous vasculitis of large vessels IMAGING General Features Best diagnostic clue Wall thickening of large vessels 989

Diagnostic Imaging Cardiovascular Location Thoracic aorta and branches Left subclavian artery is most commonly affected Ostial stenoses or occlusion of arch vessels Pulmonary artery involvement is less common Radiographic Findings Radiography Irregular or dilated descending thoracic aorta Diminished pulmonary vessels and rib notching CT Findings NECT Vessel wall thickening, iso-/hyperdense to muscle CECT Vessel wall thickening and enhancement Stenosis, occlusion, aneurysm MR Findings T1WI Wall thickening: Aorta and branches T1WI C+ Enhancement of thickened vessel wall MRA Focal/diffuse narrowing of aorta and branches Aortic dilatation (ascending > descending) Stenosis > occlusion Aortic regurgitation, dissection, aneurysm Angiographic Findings Early: Aortic wall thickening, rarely stenosis Late: Stenosis, occlusion, aneurysm; 4 types Type I: Branches of aortic arch Type II: Aorta and branch vessels Type III: Aorta; coarctation may result Type IV: Aortic dilation Nuclear Medicine Findings PET FDG uptake; ranges from low grade to intense Treatment monitoring Imaging Recommendations Protocol advice Multiplanar reconstructions for stenosis DIFFERENTIAL DIAGNOSIS Giant Cell Arteritis Affects large vessels in older patients Aortic Coarctation Aortic narrowing, rib notching More common in males PATHOLOGY General Features Etiology Autoimmune etiology is suspected Genetics Specific types of human leukocyte antigen are common among patients Gross Pathologic & Surgical Features Wall thickening of large vessels Microscopic Features Granulomatous inflammation of arterial wall Intimal proliferation; fibrosis of media and adventitia CLINICAL ISSUES Presentation Most common signs/symptoms 990

Diagnostic Imaging Cardiovascular Early or prepulseless phase Low-grade fever, malaise, weight loss, fatigue Vascular inflammatory phase Vascular insufficiency Symptoms are minimized by collateral formation Late quiescent occlusive or pulseless phase Diminished/absent pulses, vascular bruits Hypertension, aortic regurgitation Neurologic symptoms (dizziness, seizures) Triphasic pattern is seen in minority of patients Disease is usually recurrent → phases may coexist Interval between early and late phases is variable Other signs/symptoms Pulmonary hypertension when pulmonary artery is involved Demographics Age Most common in 2nd and 3rd decades of life Gender F:M = 8:1 Epidemiology Most common in Asia Affects 6 out of 1,000 persons worldwide Natural History & Prognosis Congestive heart failure is most common cause of death Hypertension is poor prognostic factor Treatment Corticosteroids are first-line treatment Cyclophosphamide and methotrexate are second-line treatment Angioplasty, surgical bypass, or stent placement for stenosis and occlusion SELECTED REFERENCES 1. Khandelwal N et al: Multidetector CT angiography in Takayasu arteritis. Eur J Radiol. 77(2):369-74, 2011 2. Restrepo CS et al: Aortitis: imaging spectrum of the infectious and inflammatory conditions of the aorta. Radiographics. 31(2):435-51, 2011

Giant Cell Arteritis Key Facts Terminology Chronic, systemic, large or medium-sized, often granulomatous vasculitis Often involves thoracic aorta and major branches Often involves temporal artery Imaging CTA Concentric aortic thickening (> 2 mm) Aortic aneurysm; classically ascending aorta Aortic dissection: Intimomedial flap MR Assessment of active inflammation Delayed enhancement after gadolinium Ultrasonography High specificity and sensitivity; operator dependent Hypoechoic halo temporal &/or axillary arteries PET Active inflammation demonstrates ↑ FDG uptake Top Differential Diagnoses Takayasu arteritis May be identical to giant cell arteritis Extremely rare in patients > 50 years Atherosclerotic disease May be difficult to differentiate radiographically, though clinical symptoms often facilitate process 991

Diagnostic Imaging Cardiovascular Similar age group Clinical Issues Headache, visual disturbances, jaw claudication Polymyalgia rheumatica Serologic markers ↑ sedimentation rate ↑ C-reactive protein Thrombocytosis Treatment Corticosteroids

(Left) Axial CTA of the chest in a patient with giant cell arteritis (GCA) shows soft tissue density material surrounding the great vessels. (Courtesy C. S. Restrepo, MD.) (Right) Axial chest CTA (same patient) shows concentric thickening of the thoracic aorta, which is a common finding in patients with GCA but is indistinguishable from Takayasu arteritis. GCA is more common in patients > 50 years old. Concomitant NECT is recommended to help differentiate from intramural hematoma. (Courtesy C. S. Restrepo, MD.)

(Left) Coronal FDG PET/CT in a patient with GCA shows diffuse uptake along the ascending aortic wall as well as along the subclavian and axillary arteries bilaterally . (Right) Coronal FDG PET/CT in the same patient shows marked uptake of FDG along the ascending aortic wall . FDG PET has excellent sensitivity and specificity for diagnosis of GCA and may be used when clinical or serological discrepancies arise during or after treatment of this condition. P.12:51

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Diagnostic Imaging Cardiovascular TERMINOLOGY Abbreviations Giant cell arteritis (GCA) Synonyms Temporal arteritis Definitions Chronic, systemic, large or medium-sized, often granulomatous vasculitis Often involves thoracic aorta and major branches Often involves temporal artery Frequently associated with polymyalgia rheumatica IMAGING CT Findings CTA Concentric aortic thickening (> 2 mm) Aortic stenosis Aortic aneurysm; classically ascending aorta Aortic dissection: Intimomedial flap MR Findings Equally accurate as CT for morphologic assessment on several sequences (e.g., T1WI, T2WI, HASTE, SSFP, etc.) Contrast-enhanced MRA is more accurate to assess areas of stenosis and aneurysm Assessment of active inflammation Best assessed on GRE sequences Delayed enhancement (i.e., ↑ signal) after gadolinium Cranial (temporal artery) involvement Ultrasonographic Findings Grayscale ultrasound High specificity and sensitivity; operator dependent Hypoechoic halo in temporal &/or axillary arteries Angiographic Findings Stenosis (often long, regular, and smooth walled) Aneurysm Nuclear Medicine Findings PET Active inflammation demonstrates ↑ FDG uptake Response to treatment correlates with ↓ FDG uptake Imaging Recommendations Best imaging tool Thickening and enhancement of aortic wall on contrast-enhanced MR Protocol advice Consider concomitant NECT to differentiate from intramural hematoma DIFFERENTIAL DIAGNOSIS Takayasu Arteritis May have similar imaging appearance to GCA Rare in patients > 50 years old Atherosclerotic Disease May be difficult to differentiate radiographically, though clinical symptoms often facilitate process Similar age group PATHOLOGY Staging, Grading, & Classification Temporal artery biopsy remains diagnostic gold standard Temporal artery biopsy can be negative (10-15%) Gross Pathologic & Surgical Features Involvement of the aorta (65%) Involvement of main aortic tributaries (57.5%) CLINICAL ISSUES Presentation Most common signs/symptoms Headache Visual disturbances 993

Diagnostic Imaging Cardiovascular Jaw claudication Other signs/symptoms Polymyalgia rheumatica Clinical profile Serologic markers ↑ sedimentation rate ↑ C-reactive protein Thrombocytosis Demographics Age Patients > 50 years old Incidence ↑ steadily with age Gender Women > men Ethnicity More common in people of Northern European and Scandinavian descent Epidemiology Prevalence in USA: 1 in 160,000 Natural History & Prognosis Prognosis for visual recovery is poor ↑ risk aortic aneurysm formation and dissection ↓ survival rate 15-30% of polymyalgia rheumatica cases eventually develop GCA Treatment Corticosteroids Aspirin Other (2nd-line therapy) Methotrexate DIAGNOSTIC CHECKLIST Consider Annual surveillance to assess for aneurysm and dissection SELECTED REFERENCES 1. Blockmans D: Diagnosis and extension of giant cell arteritis. Contribution of imaging techniques. Presse Med. 41(10):948-54, 2012 2. Castañer E et al: Imaging findings in pulmonary vasculitis. Semin Ultrasound CT MR. 33(6):567-79, 2012 3. Bossert M et al: Aortic involvement in giant cell arteritis: current data. Joint Bone Spine. 78(3):246-51, 2011 P.12:52

Image Gallery

(Left) Despite its presence, mural thickening is not apparent on NECT, whereas intramural hematoma and aortitis may 994

Diagnostic Imaging Cardiovascular appear on both NECT and CTA. NECT is helpful to determine crescentic hyperdensity that is classically seen in intramural hematoma and not in GCA. (Right) Oblique sagittal FDG PET in the same patient with GCA shows diffuse FDG uptake of the aortic wall extending from the ascending aorta to the abdominal aorta.

(Left) Axial SSFP MR of the chest in a patient with GCA shows concentric thickening of the ascending aorta . (Right) Axial delayed-enhancement MR of the chest after gadolinium in same patient shows concentric thickening of the ascending and, to a lesser extend, the descending thoracic aorta. Contrast-enhanced MR remains the best imaging method to detect mural enhancement and overall is an extremely valuable tool to assess patients with inflammatory aortitis.

(Left) Oblique sagittal late gadolinium enhancement MR of the chest in the same patient shows hyperintense signal along the ascending and descending aortic wall. While CT is equally efficient as MR at detecting mural thickening, the latter is superior at demonstrating mural enhancement. (Right) Axial T2WI MR of the chest in the same patient shows hyperintensity along the ascending aorta . The finding reflects edema related to the inflammatory nature of the disease. P.12:53

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Diagnostic Imaging Cardiovascular

(Left) PA radiograph of the chest in a patient with GCA shows mediastinal widening and marked tortuosity of the thoracic aorta, most concerning for diffusely aneurysmatic thoracic aorta. (Right) Axial CTA of the chest in the same patient shows aneurysmatic dilatation of the head and neck vessels of the aortic arch. GCA and other types of inflammatory arteritis in chronic stages may not be associated with mural thickening but with areas of dilatation and stenosis.

(Left) Axial CTA of the chest in the same patient shows dilatation of the ascending and descending thoracic aorta. (Right) Axial CTA of the chest in the same patient shows dilatation of the descending thoracic aorta with extensive intraluminal thrombus . While aneurysms classically affect the ascending aorta, they can appear along any portion of the aorta. At the ascending aorta, surgical repair should be considered when the diameter exceeds 5 cm.

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Diagnostic Imaging Cardiovascular

(Left) Oblique sagittal reformation from CTA of the chest in the same patient shows a markedly tortuous and dilated thoracic and abdominal aorta with dilated arch vessels. (Right) Oblique sagittal reformation from CTA of the chest in the same patient shows tortuosity and dilatation of the aorta and head and neck vessels. The proximal ascending aorta is normal in caliber as this patient has had surgical repair. 3D reformation may be helpful for surgical planning.

Marfan Syndrome Key Facts Terminology Congenital systemic connective tissue disorder; skeletal, cardiovascular, and ocular abnormalities Imaging Radiography Ascending aortic aneurysm Cardiomegaly Pectus deformity, scoliosis, scalloped vertebrae Pneumothorax, apical bullae CT Annuloaortic ectasia, aneurysm Aortic rupture: Crescent sign, hematoma Dissection: Intimal flap, true/false lumen Echocardiography At diagnosis to assess ascending aorta and 6 months thereafter to determine rate of enlargement MR: Similar to CT in sensitivity Top Differential Diagnoses Familial thoracic aortic aneurysm Ehlers-Danlos syndrome Bicuspid aortic valve Pathology Mutation in FBN1 gene encoding for fibrillin 1 Autosomal dominant; 25% de novo mutations Microscopy: Cystic medial necrosis Clinical Issues Cardiac/vascular abnormalities Pulmonary abnormalities Thoracic skeletal abnormalities Diagnostic Checklist Consider Marfan syndrome in young patients with ascending aortic aneurysm &/or aortic dissection

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Diagnostic Imaging Cardiovascular

(Left) Graphic compares a normal ascending aorta (left) with a well-defined sinotubular junction (arrows) and annuloaortic ectasia with sinotubular junction effacement (right). (Right) Composite image with coronal oblique CTA of a normal patient (left) and a patient with Marfan syndrome (right) shows a transition between the aortic root and the tubular ascending aorta, the sinotubular junction. The normal waist at the transition is absent in patients with Marfan syndrome.

(Left) PA radiograph of the chest in a patient with Marfan syndrome shows an abnormal convexity along the right cardiac silhouette. This finding is often associated with a dilated ascending aorta. In young patients, it is commonly associated with bicuspid aortic valve and Marfan syndrome. (Right) Axial chest CTA in the same patient with Marfan syndrome shows dilatation of the sinuses of Valsalva (4.7.× 5.0 × 5.0 cm). Three measurements bisecting each sinus are usually obtained at this level. P.12:55

TERMINOLOGY Definitions Congenital systemic connective tissue disorder characterized by skeletal, cardiovascular, and ocular abnormalities IMAGING Radiographic Findings Ascending aortic aneurysm: Mediastinal widening, right superior cardiomediastinal contour abnormality Cardiomegaly: Aortic/mitral regurgitation, cardiomyopathy Pectus deformity (excavatum, carinatum), scoliosis, scalloped vertebral bodies Pneumothorax, apical bullae CT Findings 998

Diagnostic Imaging Cardiovascular NECT Annuloaortic ectasia/aneurysm: Effacement of sinotubular junction (60-80% of patients) Lack of normal transition between aortic root and tubular portion of ascending aorta Aortic rupture, often contained Crescent sign: Crescentic eccentric aortic high-attenuation area Hematoma: Mediastinal high attenuation, hemothorax, hemopericardium CTA More sensitive than radiography Direct visualization Dissection: Intimal flap, true/false lumen Rupture: Active extravasation MR Findings Equivalent to CT, similar accuracy Direct visualization of aortic dissection Cine MR and phase-contrast imaging are optimal for valve assessment: Aortic &/or mitral regurgitation Echocardiographic Findings Initial assessment of aortic size and 6 months thereafter to determine rate of enlargement Imaging Recommendations Protocol advice Annual imaging is recommended after initial echocardiography Consider more frequent imaging if aortic diameter ≥ 4.5 cm or significant growth from baseline DIFFERENTIAL DIAGNOSIS Familial Thoracic Aortic Aneurysm Sinus of Valsalva aortic aneurysm Ehlers-Danlos Syndrome Aneurysm/rupture: Medium/large muscular arteries Systemic: Joint hypermobility, atrophic scars, easy bruising, hernias, hollow organ rupture Bicuspid Aortic Valve Ascending aortic aneurysm; bicuspid aortic valve PATHOLOGY General Features Etiology Mutation in FBN1 gene encoding for fibrillin 1 Genetics Autosomal dominant; 25% de novo mutations Microscopic Features Cystic medial necrosis CLINICAL ISSUES Presentation Clinical profile Cardiac abnormalities Mitral valve regurgitation > 50% auscultatory/echocardiographic evidence of mitral valve dysfunction, typically prolapse Progression of mitral valve prolapse to mitral regurgitation by adulthood Aortic valve regurgitation: Late occurrence from aortic annulus stretching Tricuspid valve prolapse Dilated cardiomyopathy (uncommon) Vascular abnormalities: Most common life-threatening manifestations Annuloaortic ectasia and aortic aneurysm Aortic dissection Often type A Acute onset heart failure typically from severe aortic insufficiency Extension to coronary arteries; myocardial infarction or sudden cardiac death Dilatation/dissection of descending thoracic/abdominal aorta Dilatation of pulmonary trunk Pulmonary abnormalities Bullae: Predisposed to spontaneous pneumothorax Thoracic skeletal abnormalities 999

Diagnostic Imaging Cardiovascular Pectus deformity; can contribute to restrictive lung disease Demographics Gender M=F Epidemiology Incidence: 2-3 in 10,000 individuals Natural History & Prognosis Improved prognosis with annual imaging, medical/surgical intervention Higher aortic dissection risk in pregnancy Treatment β-adrenergic receptor blockade Surgical reconstruction: Elective according to aortic diameter, or if dissection or rupture SELECTED REFERENCES 1. Ha HI et al: Imaging of Marfan syndrome: multisystemic manifestations. Radiographics. 27(4):989-1004, 2007 2. Judge DP et al: Marfan's syndrome. Lancet. 366(9501):1965-76, 2005 P.12:56

Image Gallery

(Left) Oblique sagittal SSFP and dark blood (HASTE) MR in a patient with Marfan syndrome shows dilatation of the proximal ascending aorta with effacement of the sinotubular junction. Both sequences are suitable to depict ascending aortic morphology. (Right) Oblique gadolinium-enhanced MRA in the same patient with Marfan syndrome shows dilatation of the aortic root. Volumetric acquisition and postprocessing reformations are some of the advantages of MRA over other sequences.

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Diagnostic Imaging Cardiovascular (Left) PA chest radiograph in a patient with Marfan syndrome and acute chest syndrome shows no specific evidence as to the cause of the symptoms reported in this study. (Right) Lateral chest radiograph in the same patient shows fullness of the retrocardiac space due to ascending aortic aneurysm and dissection, but the finding is nonspecific. A negative chest radiograph cannot exclude aneurysm or dissection in a patient with Marfan syndrome.

(Left) Axial CTA in the same patient shows marked dilatation of the aortic root due to Marfan syndrome. Surgical reconstruction is usually indicated when the aortic root diameter is > 5.0 cm. (Right) Axial CTA in the same patient shows an intimal flap along the ascending aorta, consistent with type A aortic dissection. Aortic dissection is a common complication occurring in Marfan syndrome and requires emergent surgical treatment. P.12:57

(Left) Oblique sagittal CTA in a patient with Marfan syndrome and acute chest syndrome shows the classic “tulip bulb” appearance due to annuloaortic ectasia. Other terms describing this appearance include “onion bulb,” “pearshaped,” and “Florence flask.” (Right) Oblique sagittal SSFP MR in a patient with Marfan syndrome and ascending aortic aneurysm shows a diastolic jet across the aortic valve, which constitutes 1 of the major cardiovascular criteria for Marfan syndrome.

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(Left) Four-chamber view SSFP MR in a patient with Marfan syndrome shows bileaflet mitral prolapse . (Right) Two-chamber SSFP MR in a patient with Marfan syndrome shows mitral valve prolapse , which is a minor criterion for Marfan syndrome. Regarding involvement of the cardiovascular system, only 1 of the minor criteria must be present. Major criteria include ascending aortic aneurysm and dissection. Only 1 of the major criteria must be present.

(Left) Axial MIP reformation from chest CTA in a patient with Marfan syndrome shows dilatation of the pulmonary trunk and central pulmonary arteries. This constitutes a minor diagnostic criterion. (Courtesy L. Heyneman, MD.) (Right) Axial NECT (same patient) shows bilateral apical bullae . Although this is a minor diagnostic criterion, it is an important abnormality that may lead to secondary spontaneous pneumothorax in patients with Marfan syndrome. (Courtesy L. Heyneman, MD.)

Pseudocoarctation Key Facts Terminology Aortic arch elongation with kinking of thoracic aorta distal to origin of left subclavian artery at level of ductus arteriosus Imaging Frontal chest radiograph Mass-like opacity in left superior mediastinum; may mimic mediastinal mass “Double left aortic arch” and “reverse 3” signs No rib notching or cardiomegaly Lateral chest radiograph Aortic arch buckled forward at isthmus 1002

Diagnostic Imaging Cardiovascular Best imaging tool: Contrast-enhanced, 3D CT and MR angiography Elongated transverse aorta and kinking and buckling of aortic arch Evaluate for complications: Aneurysm formation, subclavian steal syndrome Distinguish from COA No hemodynamically significant aortic narrowing No poststenotic dilatation or collateral vessels No left ventricular enlargement Top Differential Diagnoses Coarctation of aorta Aortic aneurysm Mediastinal mass Pathology Elongation of distal aortic arch due to abnormal growth of preductal aorta Clinical Issues No treatment necessary in asymptomatic patients Surgical treatment for complications Aneurysm formation, aortic dissection, and subclavian steal syndrome

(Left) Coronal oblique graphic of a patient with pseudocoarctation of the aorta (PCOA) demonstrates an elongated, kinked, and buckled aortic arch distal to the origin of the left subclavian artery at the level of the ductus arteriosus. (Right) Sagittal oblique VR from CTA shows kinking and mild narrowing of the proximal descending aorta at the level of the ligamentum arteriosum, highly suggestive of pseudocoarctation. No enlarged collateral bronchial, intercostal, or internal mammary arteries are present.

(Left) Posteroanterior chest radiograph shows a prominent and high-riding aortic arch 1003

. The normal heart size and

Diagnostic Imaging Cardiovascular absence of rib notching distinguish PCOA from coarctation of the aorta (COA). (Right) Lateral chest radiograph of the same patient demonstrates forward buckling of the aortic arch at the isthmus. The aorta is enlarged proximal to the narrowed segment . P.12:59

TERMINOLOGY Abbreviations Pseudocoarctation of aorta (PCOA) Synonyms Aortic buckling Aortic kinking Atypical coarctation Nonobstructive coarctation Redundant aortic arch Definitions Aortic arch elongation with kinking of thoracic aorta distal to origin of left subclavian artery at level of ductus arteriosus Distinguished from coarctation of aorta (COA) by lack of hemodynamically significant stenosis IMAGING General Features Best diagnostic clue Kinking and buckling of distal transverse arch with pressure gradient < 20 mm Hg Location Aortic isthmus at site of attachment of ligamentum arteriosum Distal to origin of left subclavian artery Size Normal caliber Dilatation > 4 cm Occasionally stenotic Morphology Elongated and tortuous aortic arch without significant obstruction Imaging Recommendations Best imaging tool Contrast-enhanced, 3D CT and MR angiography Protocol advice 3D CT angiography (CTA) in sagittal orientation with MIP and MPR reconstructions 3D high-resolution MR angiography (MRA) in sagittal view with MIP and volume-rendering algorithms Time-resolved MRA for evaluation of flow patterns and collateral pathways Phase-contrast flow quantification for measurement of peak velocities, flow direction, and pressure gradients Axial images are useful for confident evaluation of coexisting venous anomaly Radiographic Findings Frontal chest radiograph Mass-like opacity in left superior mediastinum May mimic mediastinal mass “Double left aortic arch” sign Aorta proximal to kinking appears higher than normal aortic arch Aorta distal to kinking appears lower than normal aortic arch “Reverse 3” sign Outlines medial side of aortic indentation in descending thoracic aorta No cardiomegaly No rib notching Lateral chest radiograph Aortic arch is buckled forward at isthmus CT Findings NECT Elongated and tortuous aortic arch Anterior and medial displacement of distal aortic arch 1004

Diagnostic Imaging Cardiovascular Kink in posterior and lateral margins of aorta Cervical aortic arch Associated aneurysm formation may be present CTA Elongated transverse aorta and kinking and buckling of aortic arch Notch in distal transverse arch at attachment of ligamentum arteriosum High aortic arch extending into left supraclavicular region (children) Associated aneurysm formation may be present Abnormal origins of supraaortic arteries Dilatation of brachiocephalic arteries General Distinguish from COA No hemodynamically significant aortic narrowing No poststenotic dilatation No left ventricular enlargement No collateral vessels MR Findings MRA Contrast-enhanced 3D MR angiography Kinking and buckling of elongated and tortuous transverse aorta Associated aortic aneurysm formation may be present Time-resolved MRA May show steal phenomenon in presence of subclavian artery stenosis Reversal of flow in vertebral artery Phase-contrast flow quantification MR Absence of increased peak velocity Lack of pressure gradient across kinked segment Flow reversal in steal phenomenon General Distinguish from COA No hemodynamically significant aortic narrowing No poststenotic dilatation No left ventricular enlargement No collateral vessels Angiographic Findings High position of aortic arch “Reverse 3” sign: Notch in descending aorta at attachment of short ligamentum arteriosum DIFFERENTIAL DIAGNOSIS Coarctation of Aorta Congenital narrowing of transverse arch distal to isthmus Diffuse hypoplasia of aortic arch distal to origin of innominate artery “Reverse 3” sign and rib notching on chest radiography Distinguish from PCOA P.12:60

Hemodynamically significant stenosis Elevated peak velocity on phase-contrast MR imaging Increased pressure gradient Poststenotic dilatation Left ventricular enlargement Collateral vessels Associated with congenital cardiac abnormalities Aortic Aneurysm Usually seen in atherosclerotic aorta Calcified intimal plaque usually present Saccular or fusiform dilatation Mural thrombus often present within periphery of aneurysm Commonly seen in elderly patients 1005

Diagnostic Imaging Cardiovascular May rupture or result in aortic dissection Mediastinal Mass Opacity on chest radiography CT and MR angiography can differentiate mass from PCOA PATHOLOGY General Features Etiology Elongation of distal aortic arch due to abnormal growth of preductal aorta Associated abnormalities Aberrant subclavian artery Aortic stenosis Bicuspid aortic valve Cervical aortic arch Left-to-right shunts Atrial septal defect Patent ductus arteriosus Ventricular septal defect Left superior vena cava Sinus of Valsalva aneurysm Microscopic Features Aneurysms associated with PCOA Result from cystic medial necrosis rather than atherosclerosis CLINICAL ISSUES Presentation Most common signs/symptoms Usually asymptomatic Other signs/symptoms Symptoms related to complications Aneurysm formation May be asymptomatic Shortness of breath, hoarseness, and dysphagia due to compression Aneurysm rupture or dissection Chest and back pain Shortness of breath Subclavian steal syndrome due to subclavian artery stenosis Blood pressure discrepancy between upper extremities Dizziness, vertigo, and syncope Symptoms related to associated abnormalities Demographics Epidemiology Very uncommon congenital anomaly Natural History & Prognosis Typically asymptomatic Aneurysmal dilatation may develop May result in rupture or dissection Necessitates monitoring and treatment Treatment No treatment necessary in asymptomatic patients Surgical treatment for complications Aneurysm formation Open repair: Artificial or biologic grafts Closed repair: Endovascular stent graft Aortic dissection Stanford type A: Surgery due to involvement of aortic root Stanford type B: Medical control of hypertension is standard; surgery in complicated cases Subclavian steal syndrome Angioplasty/stenting of subclavian artery (SCA) Common carotid artery-to-SCA bypass, innominate artery-to-SCA bypass, or axillary artery-toaxillary artery bypass 1006

Diagnostic Imaging Cardiovascular DIAGNOSTIC CHECKLIST Image Interpretation Pearls Sagittal views for CTA and MRA are most useful for demonstrating PCOA 3D CTA with MIP and MPR reconstructions 3D MRA with MIP and volume-rendering algorithms No hemodynamically significant aortic narrowing, poststenotic dilatation, left ventricular enlargement, or collateral vessels Allows differentiation from COA SELECTED REFERENCES 1. Kimura K et al: Pseudocoarctation of the aorta complicated by thoracic aortic aneurysm. Asian Cardiovasc Thorac Ann. 19(3-4):265-7, 2011 2. Bolen MA et al: Pseudocoarction of the aorta and crossed fused ectopic kidney assessed by multidetector computed tomography. J Cardiovasc Comput Tomogr. 4(6):405-6, 2010 3. Rao B et al: Pseudocoarctation with saccular aneurysms, left sided SVC and aberrant right subclavian artery - a case report. J Radiol Case Rep. 4(7):29-33, 2010 4. Ohnuki M et al: [Thoracic aortic aneurysm associated with pseudocoarctation; report of a case.] Kyobu Geka. 62(7):583-6, 2009 5. Son JS et al: Pseudocoarctation of the aorta associated with the anomalous origin of the left vertebral artery: a case report. Korean J Radiol. 9(3):283-5, 2008 6. Adaletli I et al: Pseudocoarctation. Can J Cardiol. 23(8):675-6, 2007 7. Matsui H et al: Anatomy of coarctation, hypoplastic and interrupted aortic arch: relevance to interventional/surgical treatment. Expert Rev Cardiovasc Ther. 5(5):871-80, 2007 8. Tanju S et al: Right cervical aortic arch and pseudocoarctation of the aorta associated with aneurysms and steal phenomena: US, CTA, and MRA findings. Cardiovasc Intervent Radiol. 30(1):146-9, 2007 P.12:61

Image Gallery

(Left) Sagittal 3D volume-rendered CTA image of a patient with PCOA demonstrates kinking and mild narrowing of the proximal descending aorta at the level of the ligamentum arteriosum. (Right) Axial CECT of a different patient with PCOA shows marked kinking and buckling of the aortic arch . No enlarged collateral bronchial, intercostal, or internal mammary arteries are identified.

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(Left) 3D volume-rendered CTA image of a patient with PCOA shows narrowing of the aortic arch and dilatation of the aorta proximal to the narrowed segment . Note the diminished size of the descending thoracic aorta distal to the site of narrowing. (Right) 3D volume-rendered CTA image of the same patient demonstrates marked kinking and tortuosity of the aortic arch . The lack of poststenotic dilatation and absence of collateral vessels are consistent with PCOA.

(Left) Axial CECT of a patient with PCOA demonstrates kinking and buckling of the aortic arch, which is elongated and tortuous . Note the notch in the distal transverse aortic arch at the attachment of the ligamentum arteriosum. (Right) Axial CECT of a patient with PCOA shows dilatation of the aorta proximal to the narrowed segment and diminished size of the descending thoracic aorta distal to the narrowed segment . Note the lack of collateral vessels in the mediastinum.

Traumatic Aortic Laceration > Table of Contents > Section 12 - Arterial > Thoracic Aorta and Great Vessels > Traumatic Aortic Laceration Traumatic Aortic Laceration Terrance T. Healey, MD Key Facts Terminology Disruption or tear of aortic wall, usually from traumatic injury during motor vehicle collision (MVC), fall, or, less commonly, penetrating trauma Synonyms: Acute traumatic aortic injury (ATAI), blunt traumatic aortic rupture (BTAR), blunt aortic trauma (BAT), blunt aortic injury (BAI) Imaging 1008

Diagnostic Imaging Cardiovascular Radiography Wide mediastinum: Hematoma, exclusion of TAI 1st rib fracture: Severe trauma, possible TAI CTA: Imaging modality of choice Aortic isthmus (90%); commonly on medial aspect Aortic wall disruption or pseudoaneurysm Irregular aortic contour Sudden aortic caliber change Sensitivity (98%), specificity (80%) Top Differential Diagnoses Wide mediastinum of other etiology Ductus diverticulum (type III) Fusiform enlargement proximal descending aorta Aortic spindle Atherosclerotic ulceration Infundibulum of bronchial-intercostal trunk Clinical Issues No specific or sensitive signs or symptoms until hemodynamic instability ensues Urgent diagnosis; 50% die within 24 hours if untreated Cause of death in 20% of high-speed MVCs Treatment Surgical repair: 70-85% survival (up to 20% surgical mortality)

(Left) AP supine chest radiograph of a young man struck by a car while running across the highway shows widening of the superior mediastinum, a left apical cap, a right tracheal/endotracheal and enteric tube deviation, thick paratracheal stripes, and loss of the aortic arch and the AP window. (Right) Axial CTA of the same patient shows active contrast extravasation from the ruptured descending aorta and a large mediastinal hematoma that produces mass effect on the esophagus, airways, and pulmonary arteries.

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(Left) Axial CTA of a 23-year-old man who sustained a stab wound to the anterior chest shows mediastinal hemorrhage and laceration of the anterior medial ascending aorta with adjacent intramural hematoma. (Right) Sagittal oblique aortogram following blunt chest trauma shows a large pseudoaneurysm at the aortic isthmus. CTA has largely replaced conventional angiography for the diagnosis of TAI but still plays an important role in TAI treatment with endovascular stent graft placement. P.12:63

TERMINOLOGY Abbreviations Traumatic aortic injury (TAI) Synonyms Acute traumatic aortic injury (ATAI) Aortic transection Blunt aortic injury (BAI) Blunt aortic trauma (BAT) Blunt traumatic aortic rupture (BTAR) Traumatic aortic pseudoaneurysm Definitions Disruption or tear of aortic wall, usually from traumatic injury during motor vehicle collision (MVC), fall, or, less commonly, penetrating trauma Partial tear vs. complete rupture IMAGING General Features Best diagnostic clue Widened mediastinum on AP chest radiography Intimomedial flap or pseudoaneurysm on CTA Location Aortic isthmus (90% of initial survivors); commonly along medial aspect at level of left pulmonary artery Aortic root (5-14% of initial survivors) Most die at scene of accident Diaphragmatic hiatus (1-12%) May be associated with diaphragmatic injury Multiple sites rarely affected Radiographic Findings Radiography Tear not visualized, identification of indirect signs related to mediastinal hemorrhage Signs of TAI sensitive but not specific Most signs present in 30-70% of patients Widened superior mediastinum (> 8 cm or > 25% of transthoracic diameter) Left apical pleural cap 1010

Diagnostic Imaging Cardiovascular Abnormal aortic arch contour Obscuration of AP window Right tracheal &/or endotracheal tube shift Right enteric tube shift Wide paravertebral stripe Wide right paratracheal stripe Inferior displacement of left mainstem bronchus 1st rib fracture indicates severe trauma and possibility of TAI 1st rib protected by clavicle and scapula, requires considerable force to break Frequency of TAI is 15-30% Any of above signs requires further investigation to exclude aortic transection Normal chest radiograph (7%) Chronic pseudoaneurysm (2% of survivors) Peripherally calcified mass at aorticopulmonary window CT Findings NECT Often shows mediastinal hematoma, rarely shows site of tear CTA Imaging modality of choice Direct visualization of aortic tear, markedly reducing need for aortography Direct signs Intimomedial flap Pseudoaneurysm or contained rupture Irregular aortic contour Sudden aortic caliber change; pseudocoarctation Rarely aortic dissection or active extravasation Sensitivity: 98% Specificity: 80% Indirect sign: Mediastinal hematoma Minimal aortic injury 10% of ATAI Isolated involvement of aortic intima Diagnosed with increasing frequency, likely because of improved spatial resolution of CT May remain stable or resolve Mimics of TAI Pulsation or streak artifact Atherosclerotic plaque Ductus diverticulum Opacified adjacent vessels: Bronchial artery, left superior intercostal vein, hemiazygos vein MR Findings MR generally has no role in evaluation of acute trauma Limited by issues related to transportation and monitoring of critically injured patients Used to identify intramural hematoma in stable patients and for follow-up Echocardiographic Findings Transesophageal echocardiography Demonstration of intimal tear, transection Visualization of hemopericardium May be technically difficult to perform in severely injured patients Most commonly used intraoperatively when CT cannot be performed Angiographic Findings Angiography Previously considered gold standard for evaluating aorta and great vessels Sensitivity: 100% Specificity: 98% Using chest radiography as guide, 10 negative angiograms performed for each TAI diagnosed Small risk of rupture Imaging Recommendations Best imaging tool CTA is imaging modality of choice 1011

Diagnostic Imaging Cardiovascular Protocol advice CTA with thin section reconstructions, multiplanar reformations, and 3D volume rendering may be useful for treatment planning High-pitch gated scan (FLASH) best if available P.12:64

DIFFERENTIAL DIAGNOSIS Widened Mediastinum False positives: Rotation, supine positioning, expiratory imaging, mediastinal fat Ductus Diverticulum (Type III) Anteromedial outpouching of aortic isthmus Smooth, gently sloping shoulders No aortic intimomedial flap Normal Variant: Fusiform Enlargement of Proximal Descending Aorta No intimomedial flap Atherosclerotic Ulceration Ulcerated plaque More common in older patients Other coexisting aortic plaques Infundibulum of Bronchial-Intercostal Trunk Takeoff may show bump in aortic contour PATHOLOGY General Features Etiology Theories of pathogenesis Rapid deceleration injury with shearing forces greatest at levels of aortic immobility: Ligamentum arteriosum, aortic root, and diaphragmatic hiatus Osseous pinch: Aorta compressed between anterior chest wall and spine; transverse tear at aortic isthmus Water hammer effect: Marked increase in intravascular pressure during aortic compression; transverse tear at isthmus Multivariate hypothesis likely: Shearing, torsion, stretching, hydrostatic forces Gross Pathologic & Surgical Features 90% at aortic isthmus From origin of left subclavian artery to ligamentum arteriosum, often anteromedially 7-8% involve ascending aorta; 2% involve descending aorta at diaphragmatic hiatus Ascending aortic tear: 20% of coroner cases; rarely survive long enough to reach hospital Range: Intimal hemorrhage to complete transection Transverse tears: Segmental (55%) or circumferential (45%); partial (65%) or transmural (35%) Noncircumferential tears more common posteriorly May involve aortic layers to varying degrees Survivors: Pseudoaneurysm usually contained by adventitia or, occasionally, mediastinal structures Adventitial injuries occur in 40% of cases and are almost always fatal due to rapid exsanguination CLINICAL ISSUES Presentation Most common signs/symptoms No specific or sensitive signs or symptoms until hemodynamic instability ensues May have chest pain or dyspnea Other signs/symptoms Acute coarctation syndrome rare Upper extremity hypertension Decreased femoral pulses Urgent diagnosis needed as 50% expire within 24 hours if untreated Multiple associated injuries: Diaphragm rupture, lung contusion, rib fractures, head injury Demographics Epidemiology Cause of death in 20% of high-speed MVCs Natural History & Prognosis 1012

Diagnostic Imaging Cardiovascular 85% die at site of trauma, most often motor vehicle accident Survival depends on time from injury to intervention 2% long-term survival Treatment Surgical repair Delayed repair may be acceptable in many cases Other injuries increase mortality of immediate repair 70-85% surgical survival quoted (up to 20% surgical mortality) Paraplegia in 10%; directly related to cross-clamp time Lower rates of paraplegia with techniques that integrate perfusion distal to clamped aorta Beta-adrenergic blocking agents decrease wall stress Endovascular stent graft repair Less invasive than surgical repair Feasible in patients with multiple comorbid injuries Complete pseudoaneurysm resolution reported at 3 months Technical success in excluding tear approaches 100% Concerning injuries to descending thoracic aorta are associated with lower operative times, blood loss, and mortality compared with open surgical repair Isolated injuries to intima (10%) may require no treatment and have been shown to resolve Limited data on optimal management DIAGNOSTIC CHECKLIST Consider Careful evaluation of chest radiograph in trauma for indirect signs of aortic transection Image Interpretation Pearls Consider chronic pseudoaneurysm in any patient with vascular calcification at aorticopulmonary window SELECTED REFERENCES 1. Aladham F et al: Traumatic aortic injury: computerized tomographic findings at presentation and after conservative therapy. J Comput Assist Tomogr. 34(3):388-94, 2010 2. Berger FH et al: Acute aortic syndrome and blunt traumatic aortic injury: pictorial review of MDCT imaging. Eur J Radiol. 74(1):24-39, 2010 3. Kwolek CJ et al: Current management of traumatic thoracic aortic injury. Semin Vasc Surg. 23(4):215-20, 2010 4. Morgan TA et al: Acute traumatic aortic injuries: posttherapy multidetector CT findings. Radiographics. 30(4):85167, 2010 P.12:65

Image Gallery

(Left) Sagittal CECT of a patient involved in a motor vehicle collision shows a transverse segmental tear at the aortic isthmus without a surrounding mediastinal hematoma. The patient had no additional chest injuries, was treated conservatively, and was followed annually with CT. (Right) Axial CTA of the same patient 5 years following trauma shows calcification and thrombus within a chronic post-traumatic aortic pseudoaneurysm. 1013

Diagnostic Imaging Cardiovascular

(Left) Composite image with axial (left) and sagittal (right) CTA of a patient with blunt chest trauma shows a minimal aortic injury manifesting with a focal intimal flap in the descending aorta without mediastinal hemorrhage. (Right) Composite image with axial (left) and sagittal (right) CECT of the same patient 9 days later shows resolution of the aortic abnormalities. Although minimal aortic injuries are often observed and usually resolve, there is limited data on their optimal management.

(Left) Axial CTA of the chest from a 60-year-old unrestrained man following a high-speed motor vehicle collision shows a linear tear from the anterior aspect of the descending aorta at the level of the diaphragm . The patient was hemodynamically unstable and was brought to the operating room. (Right) AP DSA performed intraoperatively in the same patient shows the aortic injury , which was successfully treated with a stent graft.

Ductus Diverticulum Key Facts Terminology Smooth focal bulge along anteromedial aspect of aortic isthmus at site of obliterated ductus arteriosus Imaging Chest radiography Frontal: Opacity in aortopulmonary window Lateral: Small bump-like opacity at distal transverse aortic arch Contrast-enhanced CTA or MRA Differentiate between typical and atypical appearances Evaluate for aneurysmal dilatation Differentiate from traumatic pseudoaneurysm 1014

Diagnostic Imaging Cardiovascular Ductus diverticulum aneurysm Saccular dilatation along inferior margin of aortic arch Superior margin of aneurysm extends to left subclavian artery Differentiate from traumatic pseudoaneurysm Presence of smooth, uninterrupted margins of diverticulum No intimal flap Absence of mediastinal or periaortic hematoma Top Differential Diagnoses Aortic (traumatic) pseudoaneurysm Ulcerated atherosclerotic plaque Aneurysm, aortic Kommerell diverticulum Clinical Issues Typically an incidental finding Most patients are asymptomatic Aneurysmal dilatation of ductus diverticulum necessitates intervention if > 3 cm Endovascular stent graft or conventional open surgical repair

(Left) Graphic demonstrates normal anatomy of the great vessels and the presence of a ductus diverticulum , part of the remnant of the embryologic ductus arteriosus that connected the pulmonary arteries and the aorta in utero. The rest of the ductus becomes the ligamentum arteriosum . (Right) Sagittal GRE MR image shows a smooth outpouching arising from the junction of the distal transverse aortic arch and the descending thoracic aorta. This finding is typical of ductus diverticulum.

(Left) Axial CECT shows a small focal outpouching

from the aortic arch. Note the lack of mediastinal or periaortic 1015

Diagnostic Imaging Cardiovascular hematoma. (Right) Sagittal oblique reformatted CECT of the same patient demonstrates a wide-mouthed, contrastfilled outpouching at the anteromedial aspect of the distal aortic arch. The gently sloping, symmetric shoulders form obtuse angles with the inferior aortic arch. The smooth, uninterrupted walls and lack of intimal flap exclude traumatic pseudoaneurysm. P.12:67

TERMINOLOGY Synonyms Ductus bulge Ductus bump Definitions Smooth focal bulge along anteromedial aspect of aortic isthmus at site of obliterated ductus arteriosus IMAGING General Features Best diagnostic clue Well-defined, smooth outpouching arising from distal transverse aortic arch at level of isthmus just after origin of left subclavian artery Mediastinum and aorta are otherwise unremarkable Location Along anteromedial aspect of aortic arch at aortic isthmus Size Small bulge May increase aortic diameter by average of 4.3 mm Unusually enlarged ductus referred to as aneurysm Aneurysmal dilatation of ductus diverticulum > 3 cm needs surgical intervention Morphology Smooth bulging of aortic side of ductus arteriosus Imaging Recommendations Best imaging tool 3D CT or MR angiography (CTA, MRA) Protocol advice Contrast-enhanced CTA Sagittal oblique thin MIP reconstructed images Essential to identify and assess relationship of ductus with pulmonary artery, aortic arch, and subclavian artery Visualize smooth shoulders of ductus diverticulum Pre- and post-contrast GRE and contrast-enhanced MRA Sagittal oblique and coronal thin MIP reconstructed images Radiographic Findings Frontal chest radiograph Ductus often difficult to visualize May manifest as opacity in aortopulmonary window Lateral chest radiograph Small bump-like opacity at distal transverse aortic arch CT Findings General Best visualized on sagittal oblique reconstructed images May be difficult to identify ductus diverticulum on axial images Typical appearance Wide-mouthed, contrast-filled outpouching at anteromedial aspect of distal transverse aortic arch Best diagnostic clue: Smooth, uninterrupted margins Gently sloping, symmetric shoulders form obtuse angles with inferior margin of aortic arch Increase in aortic lumen ≤1 cm Atypical appearance Steep and asymmetric sloping Acute angles at superior margin Ductus may fold back against aorta and result in pseudointimal flap Ductus diverticulum aneurysm 1016

Diagnostic Imaging Cardiovascular Saccular dilatation along inferior margin of aortic arch Superior margin of aneurysm extends to left subclavian artery Axial CTA images may show typical “3-star” sign at aortopulmonary window Proximal arch, descending aorta, and saccular aneurysm of diverticulum appear as hook-shaped structure Differentiate from traumatic pseudoaneurysm Presence of smooth, uninterrupted margins Absence of intimal flap Absence of mediastinal or periaortic hematoma MR Findings MRA MRA and post-contrast GRE images help exclude pseudoaneurysm from atypical ductus diverticulum Findings similar to those on CTA Smooth outpouching at anteromedial aspect of distal transverse aortic arch No intimal flap Angiographic Findings Contrast-filled, well-defined smooth outpouching arising from inferior margin of aortic arch No intimal flap Pseudointimal flap may be seen with diverticulum that is folded over Contrast retention is rarely seen in atypical ductus diverticulum Typically occurs in traumatic pseudoaneurysm Aneurysm of ductus diverticulum Saccular dilatation along inferior margin of distal transverse arch Superior margin of aneurysm extends to left subclavian artery DIFFERENTIAL DIAGNOSIS Aortic (Traumatic) Pseudoaneurysm Also referred to as pseudoductus Traumatic pseudoaneurysm due to partial or complete aortic transection Contrast-filled, irregular outpouching Varying size and shape Communication with aorta through narrow mouth; acute angles Intimal flap Intermediate- to high-density mediastinal or periaortic hematoma Pseudoaneurysm may compress aortic lumen Delayed clearance of contrast on angiography Ulcerated Atherosclerotic Plaque Contrast-filled, irregular outpouching P.12:68

Commonly associated with mural thickening and calcification Solitary and multifocal lesions Typically seen in elderly patients Aneurysm, Aortic Typically atherosclerotic in etiology and seen in elderly patients Usually involves both sides of aortic wall Saccular aneurysm usually involves anterolateral aspect of aorta Kommerell Diverticulum Dilatation or aneurysm of aberrant subclavian artery origin at inferior margin of distal transverse arch May be associated with right aortic arch and vascular ring PATHOLOGY General Features Etiology In developing fetus, ductus arteriosus connects pulmonary artery to aortic arch Allows most of blood from right ventricle to bypass fetal lungs in utero Ductus arteriosus normally closes after birth Ductus diverticulum is remnant of infundibular part of ductus arteriosus Located at transition from transverse aorta to descending aorta Associated abnormalities 1017

Diagnostic Imaging Cardiovascular Aneurysm of ductus diverticulum Persistent patent ductus arteriosus in infants Staging, Grading, & Classification Classification based on appearance Typical Smooth, uninterrupted margins Gentle, symmetric shoulders Atypical Shorter and steeper superior slope Microscopic Features Remnant of infundibular part of ductus arteriosus CLINICAL ISSUES Presentation Most common signs/symptoms Asymptomatic Typically an incidental finding Other signs/symptoms Aneurysmal dilatation Chest pain, embolic stroke Rupture may lead to hemodynamic instability Demographics Age More common in children than in adults Gender M=F Epidemiology 33% of infants 9-26% of adults Natural History & Prognosis Diverticulum usually shrinks over time Small residual bump at isthmus Rare aneurysm formation Hypertensive and elderly patients with atherosclerotic aorta Increased pressure load to site of ductus diverticulum results in aneurysm Rupture, thromboembolism, and infection of aneurysm may occur Treatment No treatment unless aneurysmal Aneurysmal dilatation of ductus diverticulum necessitates intervention if > 3 cm Endovascular stent graft repair Conventional open surgical repair DIAGNOSTIC CHECKLIST Image Interpretation Pearls Best imaging tool: 3D CT or MR angiography (CTA, MRA) Ductus diverticulum is best visualized on sagittal oblique reformatted images Differentiate from traumatic pseudoaneurysm Presence of smooth, uninterrupted margins Lack of intimal flap Absence of mediastinal or periaortic hematoma SELECTED REFERENCES 1. Agarwal PP et al: Multidetector CT of thoracic aortic aneurysms. Radiographics. 29(2):537-52, 2009 2. Vogler T et al: [Diverticulum of the ductus arteriosus. Cause of traumatic aortic ruptures?.] Chirurg. 78(1):47-51, 2007 3. Saito N et al: Successful endovascular repair of an aneurysm of the ductus diverticulum with a branched stent graft: case report and review of literature. J Vasc Surg. 40(6):1228-33, 2004 4. Saito N et al: Successful endovascular repair of an aneurysm of the ductus diverticulum with a branched stent graft: case report and review of literature. J Vasc Surg. 40(6):1228-33, 2004 5. Gotway MB et al: Thoracic aorta imaging with multisclice CT. Radiol Clin North Am. 41(3):521-43, 2003 6. Sugimoto T et al: Aneurysm of the ductus diverticulum in adults: the diagnostic value of three-dimensional computed tomographic scanning. Jpn J Thorac Cardiovasc Surg. 51(10):524-7, 2003 1018

Diagnostic Imaging Cardiovascular 7. Batra P et al: Pitfalls in the diagnosis of thoracic aortic dissection at CT angiography. Radiographics. 20(2):309-20, 2000 8. Ferrera PC et al: Ductus diverticulum interpreted as traumatic aortic injury. Am J Emerg Med. 15(4):371-2, 1997 9. Fisher RG et al: “Lumps” and “bumps” that mimic acute aortic and brachiocephalic vessel injury. Radiographics. 17(4):825-34, 1997 10. Oxorn D et al: The ductus diverticulum: false-positive angiographic diagnosis of traumatic aortic disruption. J Cardiothorac Vasc Anesth. 11(1):86-8, 1997 11. Grollman JH: The aortic diverticulum: a remnant of the partially involuted dorsal aortic root. Cardiovasc Intervent Radiol. 12(1):14-7, 1989 12. Morse SS et al: Traumatic aortic rupture: false-positive aortographic diagnosis due to atypical ductus diverticulum. AJR Am J Roentgenol. 150(4):793-6, 1988 P.12:69

Image Gallery

(Left) Axial CECT shows a typical ductus diverticulum arising from the distal transverse aortic arch. (Right) Coronal reformatted CECT demonstrates a typical ductus diverticulum . The close proximity of the ductus diverticulum to the pulmonary trunk reflects its underlying etiology as the remnant of the infundibular part of the ductus arteriosus that connected the pulmonary artery to the aortic arch in utero.

(Left) Axial GRE MR image of an asymptomatic patient demonstrates a focal outpouching along the distal transverse aortic arch. (Right) Sagittal GRE MR image of the same patient shows a smooth outpouching at the anteromedial aspect of the distal aortic arch. These findings are classic for a ductus diverticulum. The absence of an intimal flap and the lack of mediastinal or periaortic hematoma essentially exclude the possibility of a traumatic pseudoaneurysm. 1019

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(Left) Axial CECT demonstrates a focal outpouching along the anterior aspect of the distal transverse aortic arch, consistent with a typical ductus diverticulum. (Right) Axial CECT shows a partially thrombosed ductus diverticulum aneurysm . Although most patients are asymptomatic and require no treatment, the presence of aneurysmal dilatation > 3 cm necessitates endovascular stent graft or open surgical repair.

Abdominal Aorta and Visceral Vasculature Abdominal Aorta and Visceral Vasculature Anatomy > Table of Contents > Section 12 - Arterial > Abdominal Aorta and Visceral Vasculature > Abdominal Aorta and Visceral Vasculature Anatomy Abdominal Aorta and Visceral Vasculature Anatomy T. Gregory Walker, MD, FSIR GROSS ANATOMY Abdominal Aorta Begins at level of diaphragmatic crura and terminates at bifurcation into common iliac arteries Abdominal aorta and its branches supply arterial perfusion to all structures below diaphragm Major branches supply abdominal viscera and kidneys and also yield multiple parietal branches Lies slightly left of midline; courses anterior to vertebral bodies, parallel to inferior vena cava (IVC) Progressively decreases in caliber as it yields branches Visceral Branches of Abdominal Aorta Celiac artery (also termed celiac axis/trunk): Arises anteriorly from abdominal aorta below diaphragmatic hiatus; divides into 3 large branches Left gastric artery: Courses superiorly to supply distal esophagus and gastric cardia; anastomoses with short gastric branches from splenic artery Continues along lesser curvature of stomach giving branches anteriorly and posteriorly; terminally anastomoses with right gastric artery Splenic artery: Largest celiac branch; tortuous course to left side to supply pancreas, spleen, and stomach Pancreatic branches: Multiple branches, including dorsal pancreatic and pancreatica magna arteries, supply pancreatic body and tail Splenic branches: Splenic artery divides in hilum of spleen into multiple branches Short gastric arteries: Supply fundus of stomach Left gastroepiploic artery: Supplies left side of greater curvature of stomach, anastomoses with right gastroepiploic artery Common hepatic artery: Has multiple branches that supply liver, stomach, duodenum, gallbladder, and pancreas; becomes proper hepatic artery after yielding gastroduodenal artery

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Diagnostic Imaging Cardiovascular Gastroduodenal artery: Bifurcates into right gastroepiploic and superior pancreaticoduodenal arteries; supplies duodenum, pancreas, & stomach Cystic artery: Typically arises from right hepatic artery (70%); supplies cystic duct and gallbladder Right gastric artery: Usually arises from proper hepatic artery; supplies lesser gastric curvature and anastomoses terminally with left gastric artery Right hepatic artery: Supplies right hepatic lobe (hepatic segments 5-8) Left hepatic artery: Supplies left hepatic lobe (hepatic segments 1-4) Middle hepatic artery: Anatomic variant; when present, typically supplies hepatic segment 4 Superior mesenteric artery (SMA): Arises anteriorly from aorta just below celiac artery; supplies bowel from 2nd portion of duodenum as far distally as splenic flexure of transverse colon Inferior pancreaticoduodenal arteries: Supplies duodenum (distal to bile duct), pancreas, and spleen Anastomoses with superior pancreaticoduodenal arteries to form arterial arcade Middle colic artery: Supplies proximal 2/3 of transverse colon, up to splenic flexure May have separate right and left branches that supply respective regions of transverse colon Jejunal and ileal branches: Supply respectively named segments of small intestine Form anastomotic loops (arterial arcades), which give off vasa recta (straight arteries) Right colic artery: Supplies ascending colon and proximal transverse colon Ileocolic artery: Supplies terminal ileum, cecum, appendix, and proximal ascending colon Middle adrenal arteries: Supply adrenal glands Arise directly from aorta near origin of celiac artery; 1 or more adrenal arteries on either side Gonadal arteries: Supply ovaries and fallopian tubes (females) or testes and spermatic cords (males) Originate inferior to renal arteries but superior to inferior mesenteric artery May arise at different levels on either side Inferior mesenteric artery (IMA): Supplies distal 1/3 of transverse colon to proximal rectum Left colic artery: Supplies splenic flexure (distal transverse colon) and descending and sigmoid colon Sigmoidal arteries: Supply sigmoid colon Superior rectal (hemorrhoidal) artery: Terminal branch of IMA; supplies proximal rectum Remainder of rectum is supplied by middle and inferior rectal arteries, which are small branches that arise from internal iliac arteries bilaterally Marginal artery of Drummond: Anastomotic artery coursing along mesenteric border of colon Immediately adjacent to colon; gives off vasa recta Renal Arteries Described in “Renal Vasculature Anatomy” chapter Parietal Branches of Abdominal Aorta Inferior phrenic arteries: Paired vessels originating anteriorly from aorta; supply diaphragm from below May have separate origins or short common trunk; may also arise from celiac artery Both right and left inferior phrenic arteries give rise to multiple superior adrenal arteries Lumbar arteries: Paired vessels arising posteriorly from aorta; supply abdominal wall and spinal cord Anastomose with lower intercostal, iliolumbar, deep circumflex iliac, and inferior epigastric arteries Median sacral artery: Single midline vessel arising posteriorly from distal aorta above bifurcation; supplies lower lumbar spine, sacrum, and coccyx Anastomoses with iliolumbar and lateral sacral branches; also provides small branches to rectum Arcade Arrangement of Visceral Vessels Most visceral organs have 2 or more sources of arterial blood supply and venous drainage; important sources of collateral circulation Left gastric to right gastric arcade Connects celiac artery with distal hepatic artery Left gastroepiploic to right gastroepiploic arcade Connects common hepatic and splenic arteries Form arc of Barkow via branches (right and left epiploic) in posterior omental layer Pancreatic arcades Superior and inferior arcades connect celiac artery and SMA via gastroduodenal artery Arc of Bühler, if present, connects celiac axis and SMA P.12:71

Superior to inferior mesenteric arcades

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Diagnostic Imaging Cardiovascular Marginal artery of Drummond, coursing along descending colon, anastomoses with middle colic artery of transverse colon in splenic flexure region Arc of Riolan runs cephalad within mesentery (rather than along colonic margin) and connects left colic artery with middle colic artery Variant Anatomy of Aortic Branches Aberrant or replaced artery: Anatomic variation in which entire vessel arises from different parent vessel Replaced right hepatic artery: Arises from SMA rather than from proper hepatic artery Most common variant in hepatic arterial anatomy; 9-15% incidence Replaced left hepatic artery: Arises from left gastric artery rather than from proper hepatic artery; occurs in 3-10% of individuals Replaced common hepatic artery: Entire hepatic blood supply can arise from SMA; 2-4% incidence Common hepatic artery may arise directly from aorta rather than from celiac artery in 2% of cases Accessory artery: Anatomic variant wherein additional vessel supplies territory usually supplied by 1 artery Accessory right hepatic artery arises from SMA in 1-7% of individuals Accessory left hepatic artery arises from left gastric artery in 8-13% of individuals Celiacomesenteric trunk: Single common origin to celiac and SMA; occurs in < 1% of individuals Dorsal pancreatic artery: Usually arises from proximal splenic artery; several well-known vascular variants May arise directly from celiac artery May arise from common hepatic artery May give rise to left branch of middle colic artery or entire middle colic artery Venous Drainage of Abdominal Viscera Portal vein: 1 of 2 separate venous systems providing drainage for abdominal and pelvic viscera, formed by union of splenic and superior mesenteric vein; accounts for roughly 70% of hepatic blood supply Splenic vein: Drains spleen, stomach, colon, and pancreas via multiple tributaries Inferior mesenteric vein: Drains descending colon, sigmoid colon, and rectum via left colic, sigmoid, and superior rectal veins Pancreatic veins: Drain pancreatic tail and body Left gastroepiploic vein: Drains stomach inferiorly Short gastric veins: Drain gastric fundus Superior mesenteric vein: Drains jejunum, ileum, appendix, cecum, & ascending and transverse colon Ileocolic vein: Drains terminal ileum, appendix, cecum, and lower ascending colon Right colic vein: Drains ascending colon Jejunal and ileal veins: Drain respectively named segments of small intestine Right gastroepiploic vein: Drains greater curvature of stomach along with left gastroepiploic vein Inferior pancreaticoduodenal vein: Drains pancreatic head via arcade formed with superior pancreaticoduodenal vein Veins directly entering portal vein Left gastric (coronary) vein: Provides drainage of lesser curvature of stomach and lower esophagus Superior pancreaticoduodenal vein: Drains duodenum and pancreatic head Cystic vein: Drains gallbladder Inferior vena cava: Other venous system with multiple tributaries providing drainage to abdominal and pelvic viscera; also drains lower extremities Common iliac veins: Provide outflow drainage for both lower extremities and various pelvic viscera Lower extremity and pelvic venous drainage described separately in “Venous Anatomy” chapter Lumbar veins Interconnected on either side by vertically coursing ascending lumbar veins; latter connect with azygos vein (on right) and hemiazygos vein (on left) Also anastomose with tributaries of epigastric veins Right gonadal vein: Drains right ovary & fallopian tube (females) or right testis & spermatic cord (males) Left gonadal vein drains into left renal vein Renal veins Described in “Renal Vasculature Anatomy” chapter Right adrenal vein: Drains right adrenal grand Left adrenal vein drains into left renal vein; shares common trunk with left inferior phrenic vein Right inferior phrenic vein: Drains hemidiaphragm Left inferior phrenic vein drains into left renal vein 1022

Diagnostic Imaging Cardiovascular Hepatic veins: Provide venous drainage for entire liver; enter IVC just below diaphragm Right, middle, and left hepatic veins constitute normal venous anatomy RELATED REFERENCES 1. Ibukuro K et al: Spatial relationship between the hepatic artery and portal vein based on the fusion image of CT angiography and CT arterial portography: the left hemiliver. AJR Am J Roentgenol. 200(5):1160-6, 2013 2. Kiyosue H et al: Multidetector CT anatomy of drainage routes of gastric varices: a pictorial review. Radiographics. 33(1):87-100, 2013 3. Chen H et al: Anatomic variation of the celiac trunk with special reference to hepatic artery patterns. Ann Anat. 191(4):399-407, 2009 4. Walker TG: Mesenteric vasculature and collateral pathways. Semin Intervent Radiol. 26(3):167-74, 2009 5. Chaib E et al: The main hepatic anatomic variations for the purpose of split-liver transplantation. Hepatogastroenterology. 54(75):688-92, 2007 6. Song SY et al: Nonhepatic arteries originating from the hepatic arteries: angiographic analysis in 250 patients. J Vasc Interv Radiol. 17(3):461-9, 2006 7. Gourley EJ et al: The meandering mesenteric artery: a historic review and surgical implications. Dis Colon Rectum. 48(5):996-1000, 2005 8. Nonent M et al: Celiac-bimesenteric trunk: anatomic and radiologic description—case report. Radiology. 220(2):489-91, 2001 9. Amonoo-Kuofi HS et al: Anomalous origins of colic arteries. Clin Anat. 8(4):288-93, 1995 10. Fisher DF Jr et al: Collateral mesenteric circulation. Surg Gynecol Obstet. 164(5):487-92, 1987 11. Kuhns LR et al: Normal roentgen variant: aberrant right hepatic artery on computed tomography. Radiology. 135(2):392, 1980 12. Michels NA: Newer anatomy of the liver and its variant blood supply and collateral circulation. Am J Surg. 112(3):337-47, 1966 P.12:72

Image Gallery ABDOMINAL AORTA AND BRANCHES

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(Top) Graphic shows the abdominal aorta and its major branches. The abdominal aorta begins at diaphragmatic level and lies on the left of midline, coursing anterior to the vertebral bodies and parallel to the inferior vena cava. The abdominal aorta decreases in caliber as it yields various branches and terminates at its bifurcation into the common iliac arteries. The major abdominal aortic branches supply the abdominal viscera and kidneys. The aorta also yields multiple parietal branches (inferior phrenic, lumbar, and median sacral arteries). (Bottom) DSA shows the abdominal aorta and vessels supplying the abdominal organs. The celiac, middle adrenal, superior mesenteric, gonadal, and inferior mesenteric arteries are the major visceral arteries that arise from the abdominal aorta. The celiac, superior, and inferior mesenteric arteries supply the entire gastrointestinal system distal to the esophagus, along with the liver, spleen, and pancreas. The perfusion of the adrenal glands from the middle adrenal arteries is supplemented by the superior and inferior adrenal arteries that arise as branch vessels of the inferior phrenic and renal arteries, respectively. The gonadal arteries supply the ovaries and fallopian tubes in females or the testes and spermatic cords in males. P.12:73

CELIAC ARTERY ANATOMY

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(Top) Graphic shows normal anatomy of the celiac artery and its branches, a pattern that is present in 55-65% of individuals. The celiac artery supplies blood to the liver, stomach, lower esophagus, spleen, proximal duodenum, and pancreas. There are 3 major divisions of the celiac artery. The 1st division is typically the left gastric artery, which supplies the distal esophagus and gastric cardia. It anastomoses with short gastric branches from the splenic artery, which is the largest celiac branch and supplies the pancreas, spleen, and stomach. The 3rd celiac division, the common hepatic artery, has multiple branches that supply the liver, stomach, duodenum, gallbladder, and pancreas. It becomes the proper hepatic artery after yielding the gastroduodenal artery. (Bottom) The celiac artery, the 1st major abdominal aortic branch, arises at the level of the upper margin of the 1st lumbar vertebra. Celiac artery DSA shows variant arterial anatomy, as the origin of the left hepatic artery is replaced to the left gastric artery. This is a common anatomic variant that occurs in up to 10% of individuals. Variations in the hepatic arterial anatomy may be seen in 4045% of cases, of which the most frequent is replacement of the right hepatic artery origin to the superior mesenteric artery. P.12:74

SUPERIOR AND INFERIOR MESENTERIC ARTERIES

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(Top) Superior mesenteric artery DSA shows normal vascular anatomy. The artery arises from the abdominal aorta, just below the celiac artery origin, usually at the 1st lumbar vertebral level. It supplies the bowel from the lower duodenum through the splenic flexure of the transverse colon and also provides arterial perfusion to the pancreas. The middle, right, and ileocolic branches of the superior mesenteric artery anastomose along the mesenteric border of the colon. (Bottom) DSA shows both normal and variant anatomy of the inferior mesenteric artery, which arises from the abdominal aorta below the renal arteries and above the aortic bifurcation, at approximately the L3 vertebral level. It supplies the left colon from the splenic flexure through the upper rectum. In the splenic flexure, the left colic branch of the inferior mesenteric artery anastomoses with the middle colic artery via the marginal artery of Drummond, thus connecting the inferior and superior mesenteric arteries. In this example, however, the left branch of the middle colic artery arises from the dorsal pancreatic artery, and connects the inferior mesenteric and celiac arteries. The major inferior mesenteric artery branches are the left colic, sigmoidal, and superior rectal arteries. P.12:75

PORTAL VENOUS ANATOMY

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(Top) The portal vein is formed by the confluence of the superior mesenteric and splenic veins. It also receives blood from the inferior mesenteric, gastric, and cystic veins. Immediately before reaching the liver, the portal vein divides into right and left branches which divide into smaller venous branches and ultimately portal venules. Each venule courses alongside a hepatic arteriole, and the 2 vessels form the vascular components of the portal triad. These vessels empty into the hepatic sinusoids to supply blood to the liver. The portal vein drains blood from the gastrointestinal tract and spleen and provides roughly 70% of the blood supply of the liver. (Bottom) The main portal vein normally divides into 2 branches: Right and left portal veins. The right portal vein divides into anterior and posterior branches, with the former supplying segments 5 and 8, and the latter supplying segments 6 and 7. The left portal vein normally supplies hepatic segments 2, 3, and 4. Anatomic variants occur frequently and are present in 2035% of individuals, as in this DSA portal venogram, wherein the segment 4 branches arise from the right rather than from the left portal vein. The presence of portal vein variants increases the risk of bile duct hilar anatomical variation.

Abdominal Aortic Aneurysm > Table of Contents > Section 12 - Arterial > Abdominal Aorta and Visceral Vasculature > Abdominal Aortic Aneurysm Abdominal Aortic Aneurysm Suvranu Ganguli, MD Key Facts Terminology Abdominal aortic aneurysm (AAA) Fusiform or saccular enlargement of aorta ≥ 1.5× normal diameter (> 3 cm in abdominal aorta) AAA is described by relationship to renal arteries: Suprarenal, juxtarenal, infrarenal 1027

Diagnostic Imaging Cardiovascular Endovascular aneurysm repair (EVAR): Placement of intravascular endograft to bridge aortoiliac segments and depressurize AAA Imaging CECT/CTA allows evaluation of aneurysm size, extent, residual lumen, branch vessels, morphology Most commonly involves infrarenal aorta but can extend to involve iliac arteries (10-20%) Fusiform (80%): Circumferential aortic dilatation, degenerative etiology (e.g., atherosclerosis) Saccular (20%): Focal, eccentric outpouching, may have infectious or post-traumatic etiology Measure at largest diameter, outer wall to outer wall Leaking or ruptured aneurysm: Hematoma adjacent to or surrounding aneurysm; retroperitoneal hematoma; intraperitoneal blood Pathology Degenerative, traumatic, infectious, or inflammatory Age-related deterioration of elastic media of aorta Aortic wall infection causes mycotic aneurysm Clinical Issues Rupture risk/year: 4-5 cm (1-3%), 5-7 cm (6-11%), > 7 cm (20%) Close surveillance for aneurysms < 5 cm, unless ruptured or symptomatic EVAR with stent graft for appropriate patient Surgical open AAA repair with graft placement: Remains gold standard although EVAR is now more common

(Left) MRA MIP accurately depicts an infrarenal abdominal aortic aneurysm (AAA) and its relation to the renal arteries . There is a significant amount of mural thrombus within the AAA as the perfused lumen of the AAA is much smaller than the actual size of the AAA. (Right) Axial noncontrast CT in a patient with acute abdominal pain and hypotension reveals a leaking AAA . Blood is tracking into the right retroperitoneal space, indicating a surgical emergency.

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(Left) CTA 3D reconstruction of an infrarenal AAA shows anatomy favorable to performing EVAR. Although advanced techniques have been developed to deal with complex anatomy, the neck of the AAA is well below the origins of the renal arteries , and the AAA does not involve the common iliac arteries , making EVAR the ideal option. (Right) CTA 3D reconstruction post EVAR in the same patient shows the infrarenal proximal attachment and common iliac artery distal attachments of the intravascular endograft. P.12:77

TERMINOLOGY Abbreviations Abdominal aortic aneurysm (AAA) Definitions Abdominal aortic aneurysm Fusiform or saccular enlargement of aorta ≥ 1.5× normal diameter (> 3 cm in abdominal aorta) AAA is described by its relationship to renal arteries Infrarenal: > 1 cm of normal aorta below renal arteries Juxtarenal: Begins within 1 cm of renal arteries Suprarenal: Extends above renal arteries Inflammatory aneurysm: Uninfected AAA with enhancing circumferential inflammatory tissue 5% of AAA Abdominal pain may mimic rupture Adjacent structures (e.g., duodenum) involved Mycotic aneurysm Misnomer because any infectious agent may be underlying cause Rare but associated with high mortality Primary = direct extension from adjacent infection Secondary = embolic (endocarditis) Cryptogenic = seeding during septicemia Salmonella, Staphylococcus aureus, Streptococci Endovascular aneurysm repair (EVAR): Placement of intravascular endograft to bridge aortoiliac segments and depressurize AAA Endoleak: Persistent flow of blood outside endograft IMAGING General Features Best diagnostic clue Focal or diffuse aortic dilatation Location Most commonly involves infrarenal aorta Can extend to involve iliac arteries (10-20%) Morphology Fusiform (80%): Circumferential aortic dilatation 1029

Diagnostic Imaging Cardiovascular Degenerative etiology (e.g., atherosclerosis) Saccular (20%): Focal, eccentric outpouching May have infectious or post-traumatic etiology Measure at largest diameter, outer wall to outer wall True aneurysm involves all 3 vessel wall layers: Intima, media, adventitia Radiographic Findings Radiography Widened aortic shadow Curvilinear calcifications outlining aorta > 55% have sufficient mural calcification to be seen on plain radiography Additional cross-sectional imaging to evaluate aneurysms suspected on plain radiographs CT Findings NECT Increased attenuation area within mural thrombus may indicate acute hemorrhage Distinguishes periaortic hematoma from fibrosis Periaortic fibrosis enhances on CECT High attenuation, no enhancement to hematoma Calcification within aortic walls CECT Distinguishes residual lumen from mural thrombus Leaking or ruptured aneurysm Hematoma adjacent to or surrounding aneurysm Retroperitoneal hematoma Intraperitoneal blood CTA Delineates branch vessel anatomy Determine renal artery levels for preoperative planning Evaluate patency of inferior mesenteric artery Defines AAA neck, morphology, iliac involvement Surveillance after EVAR Identifies graft fracture or component migration Evaluates change in size of aneurysm sac Identifies endoleak; may categorize endoleak type Type I: Perfusion of aneurysm sac via incomplete/ineffective seal at endograft attachment site Almost always requires intervention Type II: Perfusion of aneurysm sac via arterial branches arising from excluded aortic segment Usually involves lumbar arteries &/or inferior mesenteric artery (IMA) Usually managed with observation; most resolve Type III: Perfusion of aneurysm sac due to mechanical problem with endograft Ineffective sealing/separation of overlapping graft components, rupture/tear of graft fabric Almost always requires intervention Type IV: Perfusion of aneurysm sac due to fabric porosity; rarely seen with current endografts Usually transient; managed with observation Type V: Continued sac enlargement without identifiable endoleak; also known as endotension May represent endoleak that cannot be identified Early experience with time-resolved CTA for improved detection and classification of endoleaks Provides dynamic information of endoleak supply NECT and CECT for pre- and post-repair evaluation MR Findings T1WI Gadolinium-enhanced MR useful in endoleak detection, characterization High signal intensity lumen Heterogeneous signal intensity mural thrombus Calcium in aneurysm walls difficult to evaluate Some limitations by artifacts from stents or coils MRA Useful for anatomic evaluation prior to EVAR Time-resolved MRA is useful in characterizing post-EVAR endoleaks poorly seen on CECT 1030

Diagnostic Imaging Cardiovascular Ultrasonographic Findings Grayscale ultrasound Fusiform dilatation of aorta Anechoic lumen, hyperechoic thrombus Color Doppler Demonstrates residual lumen Shows turbulent flow within aneurysm sac Can monitor untreated aneurysm for growth Limited by body habitus and overlying bowel gas P.12:78

Angiographic Findings DSA Opacifies only residual lumen; can underestimate true aneurysm size May not demonstrate full extent of aneurysm due to intraluminal thrombus Shows relationship of aneurysm to branch vessels (e.g., celiac, superior mesenteric artery [SMA], renal arteries) Patency of IMA and lumbar arteries Aneurysm extension into iliac arteries Often performed for pre-EVAR embolization of internal iliac artery or inferior mesenteric artery CLINICAL ISSUES Presentation Most common signs/symptoms Most AAAs are asymptomatic and found incidentally Widened aortic pulse Pulsatile abdominal mass Often found incidentally during unrelated imaging 1st sign may be catastrophic rupture Acute abdomen, back, or flank pain Rigid &/or distended abdomen Other signs/symptoms Distal embolization and ischemia Mass effect on adjacent structures Clinical profile Male, hypertensive, smoker, with hypercholesterolemia, familial AAA history Demographics Age Older population (60-80 years of age) Gender M:F = 5:1 Ethnicity USA prevalence Males: White > black Females: Equal prevalence Epidemiology Incidence increased 3× in last 3 decades Natural History & Prognosis AAAs enlarge progressively at variable rates Elective AAA repair: ≤ 5% mortality Repair of ruptured aneurysm: ≤ 80% mortality Mycotic and pseudoaneurysms: High rupture risk Treatment Options, risks, complications Rupture risk per year 4-5 cm: 1-3% 5-7 cm: 6-11% > 7 cm: 20% Close surveillance for aneurysms < 5 cm, unless 1031

Diagnostic Imaging Cardiovascular Ruptured or symptomatic Symptomatic &/or exhibiting rapid growth (> 0.5 cm/6 months) Symptoms of back pain, thrombosis, occlusion Atypical: Mycotic or saccular, or dissection present EVAR with stent graft for appropriate patient Poor surgical risk for open repair Appropriate anatomy for EVAR repair 60-80% AAAs qualify for EVAR Adequate infrarenal “neck” for proximal graft fixation and seal Circumferential thrombus, conical, dilated, or excessively angled neck configuration are problematic Adequate distal fixation zone in iliac arteries Appropriate caliber access vessels (e.g., femoral and iliac arteries) for device introduction Excessive access vessel tortuosity, calcification, occlusive disease problematic Evolving endovascular management techniques for juxtarenal and suprarenal AAA “Snorkel” or “chimney” technique involves placement of covered stents in branch arteries that will be intentionally covered by endograft and extend cephalad above endograft fabric to maintain branch perfusion Fenestrated graft technique involves customized endografts with small openings through which covered stents are placed into branch arteries May require adjunctive procedures (e.g., coil embolization, angioplasty, vascular conduit) preoperatively or intraoperatively Secondary interventions post EVAR may be necessary Treatment of clinically significant endoleaks Revascularization of limb thromboses Conversion to open repair if endograft fails Surgical open AAA repair with graft placement Remains gold standard although EVAR is now more common Durable procedure with good outcomes DIAGNOSTIC CHECKLIST Image Interpretation Pearls Image AAA in multiple projections or > 2 planes Measure perpendicular to aortic long axis Reporting Tips Maximum diameters should be measured on images orthogonal to long axis of aortic segment, which may be a double oblique plane Otherwise, diameters may be overestimated SELECTED REFERENCES 1. Jackson RS et al: Comparison of long-term survival after open vs endovascular repair of intact abdominal aortic aneurysm among Medicare beneficiaries. JAMA. 307(15):1621-8, 2012 2. Sommer WH et al: Time-resolved CT Angiography for the Detection and Classification of Endoleaks. Radiology. 263(3):917-26, 2012 3. Thawait SK et al: Group B streptococcus mycotic aneurysm of the abdominal aorta: report of a case and review of the literature. Yale J Biol Med. 85(1):97-104, 2012 4. Walker TG et al: Image optimization during endovascular aneurysm repair. AJR Am J Roentgenol. 198(1):200-6, 2012 5. Truijers M et al: Endovascular aneurysm repair: state-of-art imaging techniques for preoperative planning and surveillance. J Cardiovasc Surg (Torino). 50(4):423-38, 2009 6. Lin MP et al: A comparison of computed tomography, magnetic resonance imaging, and digital subtraction angiography findings in the diagnosis of infected aortic aneurysm. J Comput Assist Tomogr. 32(4):616-20, 2008 P.12:79

Image Gallery

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(Left) Coronal reformat CTA in the same patient shows an AAA surrounded by a thick rim of enhancing soft tissue , consistent with an inflammatory aneurysm. (Right) Axial CTA shows that the AAA extends to involve the common iliac arteries , seen in 10-20% of cases. Surrounding enhancing soft tissue indicates an inflammatory aneurysm, distinguishing it from a leaking AAA.

(Left) CTA 3D reconstruction of a suprarenal AAA shows that the neck of the AAA is above the level of the renal arteries . Performing EVAR in suprarenal AAAs can be more difficult, and many patients still undergo open or hybrid aneurysm repairs. (Right) CTA 3D reconstruction in the same patient after suprarenal AAA open surgical repair shows that the AAA has been replaced by a synthetic graft and the renal arteries have been surgically reimplanted into the graft.

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(Left) Anteroposterior DSA was taken during EVAR, prior to deployment of the proximal attachment of the endograft within the AAA . Extreme care is applied to ensure deployment of the covered portion of the proximal attachment below the level of the renal arteries . (Right) Anteroposterior DSA during EVAR after deployment of the proximal attachment shows that the renal arteries remain perfused. The AAA seen on the previous image is no longer visualized and has been excluded. P.12:80

(Left) Axial CTA performed for preoperative EVAR planning depicts a 6 cm infrarenal AAA . Swirling and layering of intravenous contrast is seen within the aneurysm given its size. (Right) Axial CTA at the same level performed 1 month post EVAR now shows exclusion of the aneurysm sac with contrast opacification of the 2 iliac limbs of the endograft . However, contrast enhancement is identified within the sac posteriorly , indicating a type II endoleak.

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(Left) Axial CTA in the same patient, performed 1 year after EVAR, shows interval reduction in size of the excluded AAA sac and spontaneous resolution of the endoleak. The type II endoleak resolved with conservative management, as many do. (Right) Coronal reformat CTA reveals a ruptured AAA . Blood is identified tracking into the right retroperitoneal space, with active contrast extravasation identified on other images.

(Left) Anteroposterior DSA was performed during EVAR for ruptured AAA. Given the acuity of the situation and the patient's anatomy, a unibody graft was deployed, sealing the ruptured AAA and the right common iliac artery origin . (Right) Anteroposterior DSA via a sheath in the excluded right common iliac artery after unibody graft deployment shows communication with AAA . The patient then underwent embolization of the right common iliac artery and femoral-femoral bypass graft placement. P.12:81

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(Left) Coronal reformat CTA 1 month post EVAR and femoral-femoral bypass graft placement shows the intact unibody endograft and resolution of the retroperitoneal hemorrhage. (Right) Axial CTA 1 month post EVAR shows patency of the unibody graft but also interval increase in size of AAA and a large amount of contrast in the AAA sac, indicating a large type II endoleak. Given the increase in AAA size and the large endoleak, intervention was recommended.

(Left) Anteroposterior DSA with a catheter in the middle colic branch of the superior mesenteric artery (SMA) reveals a prominent marginal artery of Drummond connecting the SMA to the inferior mesenteric artery (IMA). The flow of the IMA is reversed and perfusing the AAA sac . (Right) Anteroposterior angiography with a microcatheter navigated into the prominent marginal artery shows that the tip is at the origin of the IMA and injected contrast fills the aneurysm sac.

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(Left) Anteroposterior angiography after coil embolization through the microcatheter, occluding the origin of the IMA, shows that the injected contrast no longer fills the aneurysm sac, and contrast from prior injections remains trapped in the sac. (Right) Axial CTA 1 month post type II endoleak repair shows resolution of the endoleak, slight reduction in AAA size , and metallic coils at the IMA origin.

AAA With Rupture Key Facts Terminology Break in wall of abdominal aortic aneurysm (AAA) Imaging Acute Noncontrast CT: Obscuration or anterior displacement of AAA by irregular high-density mass into 1 or both perirenal spaces and, less commonly, pararenal spaces Contrast CT: Active extravasation of contrast material Chronic Noncontrast CT: Well-defined mass extending from aorta with attenuation value similar to or lower than that of native aorta Contrast CT: Lumina of both aneurysm and pseudoaneurysm, and their communication, may be enhanced Top Differential Diagnoses Contained rupture of aorta Aortic enteric fistula Aortocaval fistula Spontaneous abdominal hemorrhage due to anticoagulation Mycotic aneurysm Inflammatory aneurysm Pathology Risk of rupture related to size of aneurysm Clinical Issues Abrupt onset of severe central abdominal or back pain Pulsatile, usually tender abdominal mass Operative mortality rate: 50-75% Surgical repair as soon as diagnosis is made

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(Left) Axial NECT of the abdomen shows high-density material within the retroperitoneum, which is contiguous with the dilated abdominal aorta and displaces the right kidney anteriorly. This feature is consistent with acute rupture of the AAA. There is discontinuity of the calcified aortic wall indicating the site of the leak. (Right) Axial CECT in the same patient shows active extravasation of contrast material through the discontinuous aortic wall, consistent with rupture of AAA.

(Left) Axial NECT of the abdomen shows a dilated abdominal aorta associated with high-density material within the lumen , and aortic wall consistent with impending rupture. Note the focal dilatation of the abdominal aorta draping the spine. (Right) Axial CECT in the same patient shows that there is no active extravasation at this time. However, these findings are highly concerning for impending rupture. P.12:83

TERMINOLOGY Abbreviations Abdominal aortic aneurysm (AAA) Definitions Break in AAA wall IMAGING General Features Best diagnostic clue Acute Crescentic collection of contrast in midst of extensive blood in mesentery and retroperitoneum Chronic 1038

Diagnostic Imaging Cardiovascular Hematoma within arterial wall &/or adjacent to aneurysm Location More common in infrarenal aorta Size Rupture more common if aneurysm > 5 cm Morphology In chronic contained rupture (pseudoaneurysm), leak contained by retroperitoneal soft tissues Best imaging clue (CT) Acute Noncontrast CT Obscuration or anterior displacement of AAA by irregular, high-density mass into 1 or both perirenal spaces, and less commonly pararenal spaces Contrast CT Active extravasation of contrast material Chronic Noncontrast CT Well-defined mass extending from aorta with attenuation value similar to or lower than that of native aorta Contrast CT Lumina of both aneurysm and pseudoaneurysm, as well as their communication, may be enhanced CT Findings NECT Acute Large anteroposterior and transverse dimensions of aneurysm Focal discontinuity in otherwise circumferential calcification High-attenuation crescents within mural thrombus Retroperitoneal hematoma Anterior displacement of kidney by hematoma Enlargement or obscuration of psoas muscle Chronic Draping of posterior aspect of aorta over adjacent vertebral body Erosion of adjacent vertebral body CECT Acute Active extravasation of contrast material Focal pointing or pseudoaneurysm Findings predictive of impending rupture Rapidly increasing aneurysm size Relatively small amount of thrombus in aneurysm Relatively poorly calcified thrombus in aneurysm Hyperattenuating crescents within mural thrombus MR Findings MR not commonly used to evaluate patients suspected of having rupture of AAA Findings similar to CT findings, although calcification not well seen on MR Ultrasonographic Findings Grayscale ultrasound Presence of AAA Free fluid in peritoneum Ultrasound not accurate for determining presence of rupture Angiographic Findings Conventional angiography Active extravasation of contrast material Focal pseudoaneurysm Dilated abdominal aorta Imaging Recommendations Best imaging tool CT is imaging modality of choice for evaluation of suspected AAA rupture

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Diagnostic Imaging Cardiovascular Hemodynamically unstable patients presenting with sudden onset of abdominal pain and pulsatile abdominal mass should be taken directly to surgery without any further diagnostic tests DIFFERENTIAL DIAGNOSIS Contained Rupture of Aorta Rupture of aorta, which is contained in retroperitoneum Aortic Enteric Fistula Aortic aneurysm can rupture into gastrointestinal (GI) tract and cause massive GI bleeding Clinically may present with hypovolemia, abdominal pain, and pulsatile mass High mortality CECT: Active contrast extravasation in to GI tract Leukocyte scintigraphy: Active uptake consistent with infection Aortocaval Fistula Aortic aneurysm can rupture into inferior vena cava May present with cardiac decompensation and pulsatile mass in abdomen Rarely, AAA can rupture into retroaortic renal vein Spontaneous Abdominal Hemorrhage Due to Anticoagulation Active contrast extravasation located within site of hematoma Iliopsoas or rectus sheath involvement common Mycotic Aneurysm Usually at site of branching Focal saccular aneurysm with perianeurysmal enhancing soft tissue or abscess Inflammatory Aneurysm Periaortic enhancing soft tissue P.12:84

PATHOLOGY General Features Etiology Risk of rupture is related to size of aneurysm High risk of rupture if Size > 5 cm Rapid increase in size (> 10 mm per year) Other risk factors for rupture Hypertension Family history of aortic aneurysms History of smoking Chronic obstructive pulmonary disease Bronchiectasis Site of rupture Posterolateral aorta with hemorrhage into retroperitoneum Anterior or anterolateral aorta if rupture is intraperitoneal Gross Pathologic & Surgical Features Aneurysmal abdominal aorta Periaortic hematoma Relatively small amount of thrombus in aneurysm sac Relatively less calcified thrombus Chronic: Perianeurysmal organized hematoma CLINICAL ISSUES Presentation Abrupt onset of severe central abdominal or back pain, occasionally localized to lower abdomen, groin, or testes Pulsatile abdominal mass, usually tender AAA may be palpable in 50% of patients May be absent due to hypotension Shock Some patients with small, contained rupture may have stable blood pressure Demographics Epidemiology Approximate rates of rupture per year 1040

Diagnostic Imaging Cardiovascular < 4 cm in diameter: 0% 4-5 cm in diameter: 1-3% 5-7 cm in diameter: 6-11% > 7 cm in diameter: 20% Natural History & Prognosis Operative mortality rates: 50-75% Death usually secondary to massive intraoperative hemorrhage and cardiac complications Treatment Surgical repair as soon as diagnosis is made Rapid and maintained replacement of blood loss with crystalloid and blood transfusion to correct hypotension Endovascular repair now being used in selected patients Requires appropriate anatomy Often involves aortouniiliac endograft SELECTED REFERENCES 1. Dick F et al: Endovascular suitability and outcome after open surgery for ruptured abdominal aortic aneurysm. Br J Surg. 99(7):940-7, 2012 2. Mell MW et al: Predictors of emergency department death for patients presenting with ruptured abdominal aortic aneurysms. J Vasc Surg. 56(3):651-5, 2012 3. Saqib N et al: Endovascular repair of ruptured abdominal aortic aneurysm does not confer survival benefits over open repair. J Vasc Surg. 56(3):614-9, 2012 4. Acosta S et al: Predictors for outcome after open and endovascular repair of ruptured abdominal aortic aneurysms. Eur J Vasc Endovasc Surg. 33(3):277-84, 2007 5. Bounoua F et al: Ruptured abdominal aortic aneurysm: does trauma center designation affect outcome? Ann Vasc Surg. 21(2):133-6, 2007 6. Champagne BJ et al: Incidence of colonic ischemia after repair of ruptured abdominal aortic aneurysm with endograft. J Am Coll Surg. 204(4):597-602, 2007 7. Dillon M et al: Endovascular treatment for ruptured abdominal aortic aneurysm. Cochrane Database Syst Rev. (1):CD005261, 2007 8. Hames H et al: The effect of patient transfer on outcomes after rupture of an abdominal aortic aneurysm. Can J Surg. 50(1):43-7, 2007 9. Holt PJ et al: Epidemiological study of the relationship between volume and outcome after abdominal aortic aneurysm surgery in the UK from 2000 to 2005. Br J Surg. 94(4):441-8, 2007 10. Holt PJ et al: Meta-analysis and systematic review of the relationship between volume and outcome in abdominal aortic aneurysm surgery. Br J Surg. 94(4):395-403, 2007 11. Klonaris C et al: Endovascular repair of late abdominal aortic aneurysm rupture owing to mixed-type endoleak following endovascular abdominal aortic aneurysm repair. Vascular. 15(3):167-71, 2007 12. McPhee JT et al: The impact of gender on presentation, therapy, and mortality of abdominal aortic aneurysm in the United States, 2001-2004. J Vasc Surg. 45(5):891-9, 2007 13. Mofidi R et al: Influence of sex on expansion rate of abdominal aortic aneurysms. Br J Surg. 94(3):310-4, 2007 14. Nguyen AT et al: Transperitoneal approach should be considered for suspected ruptured abdominal aortic aneurysms. Ann Vasc Surg. 21(2):129-32, 2007 15. Peterson BG et al: Five-year report of a multicenter controlled clinical trial of open versus endovascular treatment of abdominal aortic aneurysms. J Vasc Surg. 45(5):885-90, 2007 16. Rakita D et al: Spectrum of CT findings in rupture and impending rupture of abdominal aortic aneurysms. Radiographics. 27(2):497-507, 2007 17. Schwartz SA et al: CT findings of rupture, impending rupture, and contained rupture of abdominal aortic aneurysms. AJR Am J Roentgenol. 188(1):W57-62, 2007 18. Acosta S et al: The Hardman index in patients operated on for ruptured abdominal aortic aneurysm: A systematic review. J Vasc Surg. 44(5):949-54, 2006 19. Berguer R et al: Refinements in mathematical models to predict aneurysm growth and rupture. Ann N Y Acad Sci. 1085:110-6, 2006 20. Dalainas I et al: Endovascular techniques for the treatment of ruptured abdominal aortic aneurysms: 7-year intention-to-treat results. World J Surg. 30(10):1809-14; discussion 1815-6, 2006 21. Salhab M et al: Impact of delay on survival in patients with ruptured abdominal aortic aneurysm. Vascular. 14(1):38-42, 2006 P.12:85

Image Gallery 1041

Diagnostic Imaging Cardiovascular

(Left) Axial NECT shows a dilated abdominal aorta , increased attenuation within the wall , and periaortic retroperitoneal hematoma displacing the kidney anteriorly. These features are consistent with acute rupture of an AAA. (Right) Axial CECT of the abdomen in the same patient shows focal pointing suggesting the location of rupture. Note the tracking of the hematoma from the left lateral aspect of the aortic wall into the retroperitoneum .

(Left) Axial NECT of the abdomen shows a dilated abdominal aorta with focal low-attenuation material protruding beyond the expected adventitial borders with discontinuity in the calcified aortic wall . (Right) Axial CECT in the same patient shows no contrast opacification of this focal protrusion . The abdominal aortic aneurysm with mural thrombus is seen again. These features are consistent with a contained aneurysm rupture.

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(Left) Axial CECT of the abdomen in a patient with an abdominal aortic aneurysm shows focal active contrast extravasation and a large periaortic hematoma in the retromesenteric and pararenal space. (Right) Coronal reformatted CTA in the same patient confirms active extravasation of contrast material from the abdominal aortic aneurysm with associated periaortic hematoma . These features are consistent with acute AAA rupture.

Aortic Graft Complications > Table of Contents > Section 12 - Arterial > Abdominal Aorta and Visceral Vasculature > Aortic Graft Complications Aortic Graft Complications Sanjeeva P. Kalva, MBBS, MD, FSIR Key Facts Terminology Primary aortoenteric fistula: Communication between native aorta or aortic aneurysm with GI tract Secondary aortoenteric fistula: Communication between aorta and GI tract following surgical or endovascular repair with prosthetic implants Imaging Inflammatory stranding and gas between abdominal aorta and 3rd part of duodenum post aneurysm repair Ectopic gas: Microbubble of gas adjacent to &/or within aortic graft; may suggest perigraft infection Perigraft soft tissue thickening > 5 mm (> 20 HU) Pseudoaneurysm formation ↑ attenuation of intestinal lumen contents (arterial phase); ↓ attenuation (delayed phase) Indium labeled leukocyte scan shows ↑ uptake suggesting associated infection Top Differential Diagnoses Periaortitis Retroperitoneal fibrosis Post operation Post endovascular stent Post intervention Clinical Issues “Herald” gastrointestinal bleeding followed hours to weeks later by catastrophic hemorrhage (most common) Esophagogastroduodenoscopy: Exclude obvious causes of bleeding CT: Definitive diagnosis Extraanatomic bypass with resection of graft and closure of gastrointestinal perforation Stent graft and chronic antibiotic therapy

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(Left) Axial CECT of the abdomen in a patient status post aortobiiliac graft shows lack of fat planes between the duodenum and the aortic graft. In addition, there is a small gas bubble within the surgical graft. Note the soft tissue swelling around the graft. These features are consistent with an aortoenteric fistula (AEF). (Right) Coronal labeled leukocyte scan in the same patient shows increased uptake within the aortic graft region, consistent with an infected aortic graft.

(Left) Sagittal CTA of the abdominal aorta shows adherence of duodenum to the aorta. Note a focal pseudoaneurysm of the aorta at the site where the duodenum adheres to the aorta. These features are consistent with an AEF. (Right) Axial CECT of the abdomen shows an aortic stent graft and metallic embolization coils within the aneurysm sac from endoleak repair. The duodenum adheres to the aorta with contiguous air from the lumen of the duodenum to the aortic aneurysm, suggesting an AEF. P.12:87

TERMINOLOGY Definitions Abnormal communication between aorta and gastrointestinal (GI) tract Primary aortoenteric fistula (AEF) Communication between native aorta or aortic aneurysm and GI tract Secondary AEF Communication between aorta and GI tract following surgical or endovascular repair with prosthetic implants IMAGING General Features 1044

Diagnostic Imaging Cardiovascular Best diagnostic clue Inflammatory stranding and gas between abdominal aorta and 3rd part of duodenum post aneurysm repair Location Primary AEF: Duodenum (54%), esophagus (28%), small or large bowel (15%), stomach (2%) Secondary AEF: Duodenum (73%), small bowel (19%), colon (6%), other (2%) Endoscopy findings Sensitivity: 25-80% Active bleeding, ulcer, fistulous tract, visible graft material Fluoroscopic Findings Upper GI Compression or displacement of 3rd portion of duodenum by extrinsic mass Contrast extravasation: Wall of abdominal aorta outlined by extraluminal contrast medium tracking along graft into periaortic space (rare) CT Findings Ectopic gas: Microbubbles of gas adjacent to &/or within aortic graft; may suggest perigraft infection Focal bowel wall thickening > 5 mm Perigraft soft tissue thickening > 5 mm (> 20 HU) Pseudoaneurysm formation Disruption of aneurysmal wrap ↑ soft tissue between graft and aneurysmal wrap ↑ attenuation of intestinal lumen contents (arterial phase); ↓ attenuation (delayed phase) Angiographic Findings Active extravasation of contrast material from aorta into intestine Pseudoaneurysm or nipple-like projection at site of fistula Nuclear Medicine Findings Tagged RBCs in abdominal aorta enter bowel Indium-labeled leukocyte scan shows increased uptake suggesting associated infection Imaging Recommendations Best imaging tool CT: 94% sensitive and 85% specific Protocol advice Noncontrast CT followed by CECT during arterial and delayed phase; no positive oral contrast material DIFFERENTIAL DIAGNOSIS Periaortitis Soft tissue encasing aorta and inferior vena cava (IVC) Retroperitoneal Fibrosis Mantle of soft tissue enveloping aorta, IVC, and ureters Post Operation “Normal” scarring with fluid between graft and aorta Post Endovascular Stent May have gas bubbles between stent graft and aortic wall early after placement Post Intervention May have gas in sac following percutaneous sac puncture during endoleak embolization PATHOLOGY General Features Etiology Primary: Abdominal aortic aneurysms, infectious aortitis, tumor invasion, radiation therapy Secondary: Aortic reconstructive surgery Pathogenesis Pressure necrosis of duodenal wall ↓ blood flow or injury to bowel during surgery Pseudoaneurysm formation with erosion Graft/suture line infection → anastomotic breakdown CLINICAL ISSUES Presentation Most common signs/symptoms “Herald” GI bleeding followed hours, days, or weeks later by catastrophic hemorrhage (most common) Abdominal pain, palpable pulsatile mass 1045

Diagnostic Imaging Cardiovascular Intermittent rectal bleeding and recurrent anemia Low-grade fever, fatigue, weight loss, leukocytosis Demographics Age > 55 years Gender: M:F = 4-5:1 Incidence: 0.6-1.5% after aortic surgery Onset after surgery: 21 days to 14 years (mean: 3 years) Natural History & Prognosis Prognosis very poor; up to 85% mortality Treatment Extraanatomic bypass with resection of graft and closure of gastrointestinal perforation Stent graft and chronic antibiotic therapy SELECTED REFERENCES 1. Raman SP et al: Aortoenteric fistulas: spectrum of CT findings. Abdom Imaging. 38(2):367-75, 2013 2. Xiromeritis K et al: Aortoenteric fistulae: present-day management. Int Surg. 96(3):266-73, 2011 3. Vu QD et al: Aortoenteric fistulas: CT features and potential mimics. Radiographics. 29(1):197-209, 2009 4. Baril DT et al: Evolving strategies for the treatment of aortoenteric fistulas. J Vasc Surg. 44(2):250-7, 2006

Abdominal Aortic Occlusion > Table of Contents > Section 12 - Arterial > Abdominal Aorta and Visceral Vasculature > Abdominal Aortic Occlusion Abdominal Aortic Occlusion Suvranu Ganguli, MD Key Facts Terminology Acute: Filling defect and few collaterals Embolus in infrarenal aorta or bifurcation: Partially or totally occlusive intraluminal filling defect Chronic: Aortic occlusion with extensive collaterals Distal aortic thrombosis propagating proximally Leriche syndrome: Abdominal aortic or iliac artery occlusive disease causing absent femoral pulses, bilateral claudication, and impotence Imaging Absent contrast opacification of infrarenal aorta; may extend into common iliac arteries Multiple intraabdominal collateral arteries reconstitute pelvic vessels Pathology Acute: 65% due to embolism; 35% due to thrombosis; other authors report reversed ratio Embolism: Most likely cardiac origin; can be tumor embolus with known malignancy Thrombosis: Acute thrombosis of atherosclerotic aorta or small AAA, hypercoagulable state, trauma Most common cause of occlusion: Thrombosis superimposed on severe distal aortic atherosclerosis Development of collateral pathways around occlusion crucial Clinical Issues Symptoms depend on acuteness of occlusion and amount of collateral blood flow Acute occlusion: Absent pulses and acute leg pain Chronic occlusion: Chronic ischemia, claudication Endovascular therapy has historically limited role Growing in popularity and utilization with advances in materials and techniques Surgical therapy is gold standard

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(Left) CECT MIP shows complete occlusion of the infrarenal aorta, just below the renal arteries . Dense atherosclerotic calcifications are seen along the expected course of the occluded infrarenal aorta and iliac arteries. (Right) MRA MIP depicts infrarenal aortic occlusion with reconstitution of the common iliac arteries from collateral arteries bilaterally. Note left common iliac vein is partially compressed by nonenhancing right common iliac artery.

(Left) Anteroposterior angiography from a right common femoral approach with catheter in distal aorta reveals occlusion of distal aorta and iliac arteries . Attempts at endovascular recannulization and repair were unsuccessful. (Right) CECT 3D reconstruction is shown. After failed endovascular recannulization of occluded aorta, surgical aortobifemoral bypass was performed. Note Dacron graft anastomoses at the infrarenal aorta and bilateral common femoral arteries . P.12:89

TERMINOLOGY Synonyms Aortic occlusion, aortoiliac occlusive disease, acute aortic occlusion, chronic aortic occlusion, Leriche syndrome Definitions Acute or chronic total occlusion of abdominal aorta Leriche syndrome: Abdominal aortic or iliac artery occlusive disease causing absent femoral pulses, bilateral claudication, and impotence IMAGING General Features Best diagnostic clue Acute: Abdominal aortic filling defect, few collaterals 1047

Diagnostic Imaging Cardiovascular Chronic: Aortic occlusion with extensive collaterals Location Acute: Embolus in infrarenal aorta or bifurcation Chronic: Distal aortic thrombosis propagating proximally to renal artery level CT Findings NECT Aortic wall calcification CECT Acute and chronic Normal contrast opacification of celiac axis, superior mesenteric (SMA) and renal arteries Acute: Few collaterals, if relatively acute Embolus: Intraluminal filling defect Thrombo-emboli may be present in other vessels Filling defect in infrarenal aorta, usually distally Chronic Thrombus: Occlusive intraluminal filling defect Absent contrast opacification of infrarenal aorta; may extend into common iliac arteries Multiple intraabdominal collateral arteries reconstitute pelvic vessels Distal aortic occlusion with proximal propagation of thrombus CTA Absent segment of infrarenal aorta on MIPs or reconstructions Multiple collateral vessels connecting aortic side-branch arteries above and below occlusion MR Findings T1 and T2WI: High signal intensity aortic thrombus with chronic thrombosis Signal intensity may vary with age of thrombus Time-of-flight MRA technique inaccurate due to flow-related artifacts Contrast-enhanced MR angiography preferred for better accuracy Acute occlusion Abrupt termination of abdominal aorta Filling defect/meniscus indicating embolus Chronic occlusion Infrarenal occlusion of aorta with collateral filling of distal vessels Reconstitutes at iliac or common femoral arteries Ultrasonographic Findings Grayscale ultrasound Echogenic thrombus within occluded aorta Pulsed Doppler Monophasic waveforms distal to occlusion Reduced systolic velocities Color Doppler Turbulent flow at occlusion; absent aortic flow below Echocardiographic Findings Echocardiogram Atrial myxoma or intracardiac mural thrombus can be seen in setting of embolic aortic occlusion Angiographic Findings DSA Acute: Occlusion at bifurcation with or without extension into common iliac arteries Fewer collaterals than with chronic occlusion Chronic: Occlusion of aorta just below renal arteries Multiple collateral vessels reconstitute lower extremity outflow Currently limited role in diagnosis with increased use of noninvasive modalities (CTA, MRA) Requires access from upper extremity (radial, brachial, or axillary puncture) or translumbar Imaging Recommendations Best imaging tool CTA with multiplanar reconstructions determines extent of occlusion Use multidetector scanner, adequate contrast volume, rapid bolus injection, and sophisticated post-processing Reconstructions can delineate collateral flow Protocol advice 1048

Diagnostic Imaging Cardiovascular Gadolinium-enhanced 3D MRA; good signal to noise ratio, with decreased scanning time DIFFERENTIAL DIAGNOSIS Common Iliac Artery Occlusion or Stenosis Usually related to atherosclerotic vascular disease Heavily calcified vessels May be unilateral or bilateral Multiple collaterals present Aortic Dissection Usually an extension of thoracic dissection Intimal flap separating “true” and “false” lumens Occlusion of true lumen by enlarging false lumen Aortic Trauma Retroperitoneal and periaortic hematoma History of blunt force trauma to abdomen Mid-Aortic (Coarctation) Syndrome Most lesions occur above or at level of renal arteries; proximal renal arteries involved in ˜ 80% of cases Detected in 2nd or 3rd decade due to hypertension, claudication, or rarely mesenteric ischemia Etiologies include neurofibromatosis, radiation therapy, nonspecific aortitis, and atherosclerosis Aortitis (Vasculitis) More frequent in younger patients P.12:90

Aortic involvement in Takayasu arteritis may extend from aortic root to include abdominal aorta and iliac arteries PATHOLOGY General Features Etiology Acute: 65% due to embolism; 35% due to thrombosis; other authors report reversed ratio Embolism: Most likely cardiac origin; can be tumor embolus with known malignancy Thrombosis: Acute thrombosis of atherosclerotic aorta or small AAA, hypercoagulable state, trauma Most common cause of occlusion: Thrombosis superimposed on severe distal aortic atherosclerosis Development of collateral pathways crucial Pancreaticoduodenal arcade (celiac to SMA) Arc of Riolan (SMA to IMA) Marginal artery of Drummond (SMA to IMA) along mesenteric side of colon Iliolumbar (lumbar arteries to internal iliac branches) Superior to inferior epigastric arteries Gluteal collaterals Gross Pathologic & Surgical Features Severe atherosclerosis of aorta, calcification CLINICAL ISSUES Presentation Most common signs/symptoms Symptoms depend on acuteness of occlusion and amount of collateral blood flow Leriche syndrome triad: Absent femoral pulses, claudication, impotence Acute occlusion causes acute ischemia Absent pulses and bilateral acute leg pain Acute abdominal symptoms Chronic occlusion causes chronic ischemia Absent femoral or lower extremity pulses Claudication Other signs/symptoms Acute Symptoms mimicking spinal cord compression Acute onset hypertension Cool skin Chronic Global lower extremity trophic changes in nails or skin 1049

Diagnostic Imaging Cardiovascular Claudication or rest pain; tissue loss Clinical profile Acute: Severe dehydration, hypercoagulable state, atrial myxoma Cardiac dysfunction (associated with poor prognosis in aortic occlusion) Chronic: Atherosclerosis, hypertension, diabetes mellitus, smoking history Demographics Age > 60 years of age Gender Acute aortic occlusion: Females > males Female gender is risk factor for embolism Chronic aortic occlusion: Males > females Male gender is risk factor for atherosclerosis Natural History & Prognosis Acute aortic occlusion: > 50% mortality rate Chronic aortic occlusion: Lower morbidity and mortality rates than acute occlusion Treatment Options, risks, complications Cardiac complications, recurrent embolization, progression to thrombosis, renal failure, amputation Medical management: Alter risk factors; antiplatelet therapy or anticoagulation Exercise regimen Endovascular therapy has historically limited role depending on chronicity, length of occlusion, distribution of disease Growing in popularity and utilization with advances in materials and techniques Bare metal stents and stent grafts growing in use Good mid-term and long-term results encouraging Surgical therapy is gold standard Aortobiiliac bypass for reconstitution at iliacs Aortobifemoral bypass for occlusion reconstituting at femoral arteries Extraanatomic bypass (e.g., axillobifemoral) Endarterectomy (rarely performed) DIAGNOSTIC CHECKLIST Consider Diagnosis may be delayed due to varied presentations Delayed diagnosis and treatment yields poor outcome Patients with chronic occlusion have high likelihood of arterial disease in other vessels Image Interpretation Pearls Nonocclusive filling defect is embolus Occlusive filling defect is thrombus SELECTED REFERENCES 1. Andrási TB et al: A minimally invasive approach for aortobifemoral bypass procedure. J Vasc Surg. 53(3):870-5, 2011 2. Roxas R et al: Rapid detection of aortic occlusion with emergency ultrasonography. Ann Emerg Med. 58(1):21-3, 2011 3. Yamamoto H et al: Acute occlusion of the abdominal aorta with concomitant internal iliac artery occlusion. Ann Thorac Cardiovasc Surg. 17(4):422-7, 2011 4. Chiesa R et al: Aortobifemoral bypass grafting using expanded polytetrafluoroethylene stretch grafts in patients with occlusive atherosclerotic disease. Ann Vasc Surg. 23(6):764-9, 2009 5. Salerno M et al: Images in vascular medicine. Collateral pathways perfusing Leriche's syndrome evaluated by multislice spiral computed tomography. Vasc Med. 9(3):229-30, 2004 6. Ruehm SG et al: Contrast-enhanced MR angiography in patients with aortic occlusion (Leriche syndrome). J Magn Reson Imaging. 11(4):401-10, 2000 7. Ligush J Jr et al: Management and outcome of chronic atherosclerotic infrarenal aortic occlusion. J Vasc Surg. 24(3):394-404; discussion 404-5, 1996 P.12:91

Image Gallery

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Diagnostic Imaging Cardiovascular

(Left) CECT coronal reformat depicts infrarenal aortic occlusion . The occlusion begins at the level of the renal arteries , although both renal arteries remain patent and the kidneys are normally perfused. (Right) CECT coronal reformat shows near complete occlusion of the abdominal aorta . Collateral formation with enlargement of a lumbar artery and reperfusion of the iliac arteries is seen.

(Left) CECT 3D reconstruction shows chronic abdominal aortic occlusion and typical collateral pathway formation between the internal mammary, superior epigastric, and inferior epigastric arteries , bypassing the aorta. An enlarged marginal artery of Drummond is also seen. (Right) CECT coronal reformat in a patient with chronic abdominal aortic occlusion displays extensive epigastric hypertrophy and collateralization along the anterior abdominal wall.

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(Left) CECT 3D reconstruction shows a patient with chronic occlusion of the abdominal aorta with extensive collateral formation . However, the patient was symptomatic despite the collateralization. (Right) CECT 3D reconstruction shows the patient after aorto-femoral bypass graft and femoral-femoral bypass graft placements. The aorto-femoral bypass graft also contained jump grafts to the mesenteric and renal arteries completely reconstructing the abdominal aorta.

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Section 13 - Venous Approach to Venous Conditions Approach to Venous Conditions Sanjeeva P. Kalva, MBBS, MD, FSIR Terminology Venous anomaly Venous thrombosis Venous insufficiency Venous compression Venous aneurysms (varix) Venous malformations Anatomy-based Imaging Issues Imaging of venous diseases requires thorough understanding of venous anatomy, pathophysiology, and clinical aspects, including treatment options of various venous diseases. With the advent of high-quality cross-sectional imaging techniques, catheter-based venography is rarely performed for the diagnosis of venous diseases, but it remains the best imaging technique to assess flow dynamics, collateral flow, intravascular pressure, and posttreatment effects. Extremity veins can be assessed adequately with ultrasound and color Doppler. The intrathoracic and intraabdominal veins are difficult to assess with ultrasound and often require the use of CT venography and MR venography for adequate visualization. Intravascular ultrasound is usually a part of catheter venography and is used to assess mural abnormalities of the venous wall. Pathology-based Imaging Issues Venoocclusive Diseases Venoocclusive diseases include acute and chronic deep venous thrombosis, venous webs, primary or secondary tumor invasion of the veins, and extrinsic venous compression. Acute venous thrombosis results in obliteration of the venous lumen with acute thrombus, venous expansion, and perivenous edema. Often, acute thrombus is anechoic or hypoechoic on grayscale ultrasound and may be difficult to detect unless compression technique or color Doppler is used. On compression ultrasound, acutely thrombosed veins are noncompressible. Color flow imaging shows absence of flow in the thrombosed vein. CT venography demonstrates a filling defect within the thrombosed vein, and the vein wall may enhance in a rim-like fashion with perivenous stranding. Both noncontrast MR venography and contrastenhanced MR venography are helpful in detecting acute venous thrombosis. The findings are similar to those of CT venography. T2-weighted images are helpful in assessing perivenous inflammation. Chronic deep venous thrombosis results in scarring of the vein with complete occlusion or partial recanalization of the vein. Imaging demonstrates a 1052

Diagnostic Imaging Cardiovascular partially compressible, small-caliber vein with multiple flow channels within the lumen. Intravenous tumor extension or primary venous tumor (such as leiomyomatosis) appears similar to that of acute deep venous thrombosis (intraluminal filling defect on CT venography and MR venography and noncompressible vein on ultrasound); however, contrast-enhanced studies demonstrate enhancement of the intravenous tumor that is not observed in bland (nontumor) thrombus. Venous webs are usually congenital; however, acquired webs can occur from chronic deep venous thrombosis and extrinsic venous compression. Congenital webs occur in large veins, such as the inferior vena cava and hepatic veins, and are best observed on ultrasound, high-resolution double inversion-recovery T1-weighted MR, and catheter venography. These appear as thin, transverse, linear soft tissue structures and, depending on the severity of obstruction, there may be venous dilation or collateral formation peripheral to the obstruction. Acquired webs are usually multiple and of varied thickness and may be seen on imaging as discrete webs. However, these are best observed on catheter venography and intravascular ultrasound. Extrinsic venous compression can occur from normal or abnormal adjacent arteries, muscles, and bones or from pathological structures such as tumors and enlarged lymph nodes. CT and MR are helpful in detecting pathological causes of venous compression. Dynamic compression of the veins (as seen in thoracic outlet syndrome and popliteal venous compression) can be assessed on color Doppler, MR venography, and CT venography; however, it is best appreciated on dynamic catheter venography. Color Doppler evaluation of the peripheral veins may allow detection of secondary effects of central venous occlusion by demonstrating absence of respiratory phasicity in the venous flow. Extrinsic venous compression may also lead to development of collateral veins depending on the severity of obstruction, peripheral venous thrombosis, and peripheral venous valvular insufficiency. Chronic repetitive compression over the veins by arteries (as seen in May-Thurner syndrome) may lead to chronic endothelial injury, mural spurs, and chronic webs and occlusion. Catheter venography and intravascular ultrasound are the most useful imaging tests to assess such extrinsic arterial compression. Time-of-flight sequences of MR venography aimed at imaging venous flow may also be helpful in the assessment of the hemodynamic significance of such extrinsic venous compression through detection of flow reversal or collateral flow. Following endovascular therapy, venous flow assessment can be performed with color Doppler, CT venography, MR venography, and catheter angiography. MR venography is not useful in assessing patency of venous stents. Venous Insufficiency Venous insufficiency results from valvular function failure that occurs as a result of primary venous wall/valve disease or secondary to chronic deep venous thrombosis or chronic venous hypertension from a central venous obstruction. Chronic venous insufficiency of the lower extremities may lead to varicose veins in the legs, pedal edema, dermatitis related to chronic venous stasis, lipodermosclerosis, and venous ulcerations. Patients usually present with cosmetic embarrassment from varicose veins, leg pain or discomfort, leg swelling, skin discoloration, or ulcer. Imaging allows accurate identification of the location and severity of valvular incompetence. Color Doppler evaluation is the best imaging test to assess venous insufficiency of the extremities. Valve closure times are assessed during a stress maneuver (e.g., Valsalva or squeeze-release technique). The normal valve closure times are as follows: 0.5 second for saphenous veins and 1 second for deep veins. Chronic venous insufficiency affecting the perforator veins is often difficult to assess, but dilated (> 3.5 mm in diameter) perforator veins are usually considered abnormal. MR venography and CT venography have shown promise in detecting dilated perforator veins. Chronic venous insufficiency may also affect the gonadal veins leading P.13:3 to varicocele in men and pelvic varices in women. These could be detected on multiphase contrast-enhanced MR venography and catheter venography. Venous Aneurysms Venous aneurysms are rare. They are usually congenital or occur as a result of valvular insufficiency or an arteriovenous communication. Congenital venous aneurysms are either incidentally detected or identified during a work-up of a pulmonary embolism. Venous aneurysms affecting the extremity veins can be well assessed on ultrasound; however, those involving the chest and abdomen are best assessed on CT venography and MR venography. Catheter venography may sometimes be false negative if the aneurysm is thrombosed. Arteriovenous Communications and Venolymphatic Malformations Arteriovenous communications include arteriovenous fistula (congenital, traumatic, or iatrogenic), arteriovenous malformations, and arteriovenous tumoral shunting. Such communications can result in localized venous hypertension, valvular insufficiency, and enlarged primary and collateral veins. The presence of arterialized waveforms in the veins during color Doppler evaluation suggests an arteriovenous communication. Accurate localization of the arteriovenous communication can be best performed with catheter arteriography; however, multiphasic CT venography and MR venography are often the initial imaging tests to assess arteriovenous communications due to their noninvasiveness. Venolymphatic malformations are best assessed with MR. Congenital Anomalies 1053

Diagnostic Imaging Cardiovascular Congenital venous anomalies are common but are of clinical significance only if major veins (such as the inferior vena cava) are atretic. Duplicated and abnormally persistent veins are of significance when instrumentation or surgical therapy is planned. Major venous anomalies can be well evaluated with CT venography and MR venography. Imaging Protocols Color Doppler Ultrasound Extremity veins are best assessed on grayscale ultrasound combined with color Doppler. Each named vein is assessed in transverse and longitudinal planes. Compression technique is applied while imaging the vein in a transverse plane to assess venous patency. Venous flow dynamics are assessed in the longitudinal plane. The veins of the extremities demonstrate a respirophasic flow pattern unless centrally obstructed and show flow augmentation when distally compressed. The abdominal veins could be visualized in thin individuals, but the evaluation is often limited due to bowel gas and body habitus. Computed Tomography Venography Direct CT venography refers to imaging of the veins in the territory where intravenous contrast material is injected. This study is usually performed to assess the extremity veins while the hand or foot vein is injected. The contrast material is diluted with normal saline to 10-20% concentration to avoid streak artifacts. Indirect CT venography refers to imaging of the veins of clinical interest during the venous phase following an intravenously administered bolus of a contrast material. This technique usually requires a large volume (100-150 mL) of normal-strength iodinated contrast material and adequate time delay (90-120 seconds for intraabdominal veins and 120-180 seconds for extremity veins) from contrast material administration until start of scanning. Thin sections (2.5-5 mm) are adequate to assess venous thrombosis. Magnetic Resonance Venography Noncontrast MR venography is useful in the assessment of venous patency (via double inversion T1-weighted images, steady-state free precession sequences, time-of-flight sequences) and flow direction (via time-of-flight sequences). Contrast-enhanced MR venography is performed as a multiphase examination to capture the various phases of contrast material flow through the arteries, capillaries, and veins. Contrast-enhanced MR venography is highly useful in the assessment of venous patency and detection of collateral flow. Multiphasic studies following contrast material administration allow detection of flow dynamics. MR venography could also be performed in various body positions to assess dynamic extrinsic venous compression. Catheter Venography Ascending venography refers to the catheterization of a peripheral vein and injection of a large volume of contrast material to assess the proximal vein patency. This study is commonly used to assess the extremity veins by cannulating the hand or foot vein. It is important to position the extremity in an anatomical position to adequately assess the veins. Images are obtained in two orthogonal planes. Descending venography is performed to assess valvular competence. A catheter is positioned in a vein (common femoral vein if assessing the saphenofemoral junction valve), and contrast material is injected while the patient performs the Valsalva maneuver so that the retrograde flow of contrast material can be detected. Intravascular Ultrasound Intravascular ultrasound is usually part of catheter venography. The ultrasound probe is mounted on a catheter and used to assess the lumen and luminal surface of the venous wall. Images are obtained in both transverse and longitudinal planes. Intravascular ultrasound is also useful in assessing the patency of intravascular stents. Selected References 1. McLafferty RB: The role of intravascular ultrasound in venous thromboembolism. Semin Intervent Radiol. 29(1):105, 2012 2. Lin YT et al: Comprehensive evaluation of patients suspected with deep vein thrombosis using indirect CT venography with multi-detector row technology: from protocol to interpretation. Int J Cardiovasc Imaging. 26(Suppl 2):311-22, 2010 3. Spritzer CE: Progress in MR imaging of the venous system. Perspect Vasc Surg Endovasc Ther. 21(2):105-16, 2009 4. Fraser JD et al: Venous protocols, techniques, and interpretations of the upper and lower extremities. Radiol Clin North Am. 42(2):279-96, 2004 5. Katz DS et al: Current DVT imaging. Tech Vasc Interv Radiol. 7(2):55-62, 2004

Venous Anatomy Venous Anatomy T. Gregory Walker, MD, FSIR UPPER EXTREMITY VENOUS ANATOMY Upper Extremity Superficial Veins Cephalic vein: Courses along radial aspect of arm Ascends in front of elbow between brachioradialis and biceps brachii muscles Communicates with basilic vein via median cubital (median basilic) vein at level of elbow 1054

Diagnostic Imaging Cardiovascular Located in superficial fascia along anterolateral surface of biceps brachii muscle Passes superiorly between deltoid and pectoralis major muscles in deltopectoral groove Drains into axillary vein in arch-like configuration Basilic vein: Courses along ulnar aspect of arm Ascends medially along biceps in upper arm Frequently joins brachial vein in upper arm Upper Extremity Deep Veins Brachial vein: Usually paired Terminate(s) in axillary vein Axillary vein: Returns blood from lateral aspect of thorax, axilla, and upper extremity Starts at border of teres major muscle as continuation of brachial vein; ends at outer edge of 1st rib Tributaries include basilic and cephalic veins Subclavian vein: Continuation of axillary vein Courses from outer border of 1st rib to medial border of anterior scalene muscle Subclavian vein lies anterior to anterior scalene muscle whereas artery lies posterior Thoracic duct drains into left subclavian vein Duct enters near subclavian vein junction with left internal jugular vein CERVICOTHORACIC VENOUS ANATOMY Cervical Veins Internal jugular vein: Formed by union of sigmoid and inferior petrosal sinuses with common facial vein Courses with common carotid artery and vagus nerve inside carotid sheath Provides venous drainage for brain, face, and neck Joins with subclavian vein medially to form brachiocephalic vein External jugular vein: Formed by union of posterior retromandibular vein and posterior auricular vein Courses superficial to sternocleidomastoid muscle Drains into subclavian vein more laterally than does internal jugular vein Provides venous drainage for exterior of cranium and deep parts of face Thyroidal veins: Arise from venous plexus surrounding thyroid gland; often multiple in number Superior & middle thyroidal: Direct tributaries to internal jugular vein Inferior thyroidal: Drain into brachiocephalic veins Vertebral vein: Derived from small venous tributaries that form plexus around vertebral artery Plexus ends in single trunk that exits from 6th cervical vertebral transverse foramen Enters brachiocephalic vein posteriorly near origin Thoracic Veins Brachiocephalic (innominate) vein: Formed by union of subclavian and internal jugular veins Veins join at level of sternoclavicular joint Superior vena cava (SVC): Formed by union of right and left brachiocephalic veins Courses posterior to manubrium and sternum on the right Azygos vein: Formed by union of ascending lumbar and right subcostal veins at 12th thoracic vertebral level Ascends in posterior mediastinum; arches over right mainstem bronchus to join SVC Drains posterior thorax and abdomen into SVC Hemiazygos vein: Begins in left ascending lumbar or left renal vein Passes upward through left crus of diaphragm to enter thorax on left; mirrors lower azygos vein At ˜ 9th thoracic vertebra, courses rightward behind aorta and esophagus to enter azygos vein Accessory hemiazygos vein: Courses inferiorly along left side of spine, draining upper posterior thorax Drains 4th-7th posterior intercostal veins Either courses rightward at ˜ 8th thoracic vertebra to join azygos vein or ends in hemiazygos vein Superior intercostal veins: Right- and left-sided veins that drain 2nd-4th intercostal spaces posteriorly Right superior intercostal vein drains into azygos vein Left drains into left brachiocephalic vein Internal thoracic (mammary) vein: Arises from superior epigastric vein; terminates in brachiocephalic vein Paired vein that drains anterior chest and breasts Receives drainage from anterior intercostal veins LOWER EXTREMITY VENOUS ANATOMY Lower Extremity Superficial Veins Great saphenous vein (GSV): Originates from dorsal venous pedal arch; courses anterior to medial malleolus Ascends medially in lower leg, courses over medial epicondyle of femur at knee level, then runs anteromedially along thigh Joins common femoral vein at saphenofemoral junction (SFJ) in femoral triangle region 1055

Diagnostic Imaging Cardiovascular Anastomoses freely with small saphenous vein (SSV) in calf Has tributaries from medial, lateral, & posterior thigh May form accessory saphenous vein branches that enter GSV at or near SFJ Superficial epigastric, superficial iliac circumflex, & superficial external pudendal veins join GSV at SFJ Small saphenous vein: Originates laterally from dorsal venous pedal arch; courses behind lateral malleolus Ascends along posterior calf alongside sural nerve; passes between gastrocnemius muscle heads Often variable anatomy of SSV drainage Usually enters popliteal vein at saphenopopliteal junction around level of knee joint May not drain into popliteal vein but instead may enter GSV at variable level Main SSV may continue as Giacomini vein Giacomini vein: Communicating vein between GSV and SSV; usually is a thigh extension of an SSV branch Ascends along posterior thigh Typically joins GSV in upper 1/3 of thigh Found in roughly 60-70% of individuals Lower Extremity Deep Veins Calf veins: 3 sets of paired veins draining lower leg P.13:5

Anterior tibial veins: Arise from dorsal pedal veins; run in interosseous membrane between tibia & fibula Join posterior tibial veins to form popliteal vein Drain ankle, knee, and tibiofibular joints along with anterior portion of lower leg Posterior tibial veins: Receive blood from medial and lateral plantar veins Drain posterior calf and plantar surface of foot Receive most important calf perforator veins: Cockett perforators (superior, medial, and inferior) Peroneal (fibular) veins Return blood from lateral compartment of calf Drain into posterior tibial veins Popliteal vein: Formed by junction of posterior and anterior tibial veins Courses adjacent to popliteal artery behind knee Returns blood from paired calf veins Femoral vein: Continuation of popliteal vein Begins at adductor canal; ends at inguinal ligament Receives drainage of lower extremity via popliteal, profunda femoral, and great saphenous veins Some use term “superficial femoral vein” for lower segment of femoral vein coursing in adductor canal Differentiates femoral vein segments before and after profunda femoral vein inflow Usage of term is discouraged; causes confusion as this vein is deep rather than superficial Lower Extremity Perforator Veins Connect superficial and deep veins Valves direct blood from superficial to deep system ˜ 150 perforator veins in each leg Major lower extremity perforators Foot and ankle perforators: Connect to pedal arches Leg (calf) perforators: Connect saphenous branches with paired deep veins of calf Include posterior tibial perforator veins (formerly termed Cockett perforators) Knee perforators: Connect GSV with popliteal and other deep veins at knee level Include medial knee perforators (formerly termed Boyd perforators); common site for varicose veins Thigh perforators: Connect GSV to femoral vein Include distal thigh perforator (formerly termed Dodd perforator) and medial thigh perforator (formerly termed Hunter perforator) ABDOMINAL & PELVIC VENOUS ANATOMY Systemic Abdominal and Pelvic Veins Inferior vena cava (IVC) and tributaries: Drain both lower extremities and abdominal and pelvic viscera that are not alimentary tract components External iliac veins: Arise at inguinal ligament; terminate when joined by internal iliac veins 1056

Diagnostic Imaging Cardiovascular Connect femoral veins to common iliac veins Inferior epigastric and deep circumflex iliac veins drain into external iliac veins Internal iliac (hypogastric) veins: Begin near greater sciatic foramen; join with external iliac vein to form common iliac vein Tributaries drain external genitalia, uterus, vagina, prostate, bladder, lower rectum, gluteal muscles Common iliac veins: Formed by union of external and internal iliac veins Outflow drainage for lower extremities and pelvis Remainder of venous drainage related to IVC and tributaries is described separately in “Abdominal Aorta and Visceral Vasculature Anatomy” chapter Portal Venous System Portal vein and tributaries: Responsible for directing blood from components of gastrointestinal tract to liver Described separately in “Abdominal Aorta and Visceral Vasculature Anatomy” chapter VARIANT VENOUS ANATOMY Superior Vena Cava and Tributaries Left SVC: Most common congenital venous anomaly of thorax Only seen in isolation in 10% of cases; majority accompanied by normal but smaller right SVC Termed SVC duplication if both present Can result in right-to-left shunt in minority of cases Left azygos arch: May occur in association with left SVC Left superior intercostal vein forms communication between left SVC and accessory hemiazygos vein Inferior Vena Cava and Tributaries Duplicated IVC: Results from persistence of both supracardinal veins Left IVC typically ends at left renal vein, which crosses anterior to aorta to join right IVC Prevalence of 0.2-3% Left IVC: Results from regression of right supracardinal and persistence of left supracardinal vein Left IVC joins left renal vein, which crosses to unite with right renal vein & form normal suprarenal IVC Prevalence of 0.2-0.5% Azygos continuation of IVC: Absence of hepatic IVC IVC receives blood from kidneys and passes posteriorly to enter thorax as azygos vein Azygos vein joins SVC at normal location in chest Circumaortic left renal vein: 2 left renal veins Superior renal vein receives left adrenal vein and crosses aorta anteriorly Inferior renal vein receives left gonadal vein and crosses aorta posteriorly Prevalence may be as high as 8.7% Retroaortic left renal vein: Single-variant renal vein Passes posterior to aorta May result in posterior nutcracker syndrome Prevalence of 2.1% RELATED REFERENCES 1. Bannon MP et al: Anatomic considerations for central venous cannulation. Risk Manag Healthc Policy. 4:27-39, 2011 2. Innasimuthu AL et al: Persistent left-sided superior vena cava—a pacing challenge. Acute Card Care. 9(4):252, 2007 3. Salik E et al: Three-dimensional anatomy of the left central veins: implications for dialysis catheter placement. J Vasc Interv Radiol. 18(3):361-4, 2007 4. Barberini F et al: The thigh extension of the small saphenous vein: a hypothesis about its significance, based on morphological, embryological and anatomo-comparative reports. Ital J Anat Embryol. 111(4):187-98, 2006 5. Mullarky RE: Anatomy of the great saphenous vein in the thigh. Northwest Med. 65(10):839-42, 1966 P.13:6

Image Gallery NORMAL ABDOMINAL SYSTEMIC AND PORTAL VENOUS ANATOMY

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Graphic shows normal abdominal systemic and portal venous anatomy. The inferior vena cava (IVC) is formed by the confluence of the right and left common iliac veins and thus provides central venous return for the lower extremities in addition to the pelvis and abdomen. Because the IVC is located to the right of the midline, there are some normally occurring asymmetries in venous drainage patterns. The gonadal and adrenal veins drain directly into the IVC on the right, but into the renal vein on the left. The left and right renal veins both drain directly into the IVC. All of the lumbar veins and hepatic veins usually drain directly into the IVC. The IVC drains into the right atrium and also anastomoses in the abdomen with the azygos venous system. The latter is formed by the ascending lumbar veins along the right side of the lumbar spine. Normally, the portal venous system is completely separate from the IVC and the systemic veins. The portal venous system is responsible for returning blood from various parts of the gastrointestinal tract to the liver and supplies roughly 70% of the liver perfusion. The portal vein is formed by the union of the superior mesenteric and splenic veins. Other important tributaries of the portal vein include the inferior mesenteric, gastric, and cystic veins. P.13:7

VENOUS ANATOMY OF NECK, THORACIC INLET, AND UPPER THORAX

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(Top) Graphic shows the venous anatomy of the neck, thoracic inlet, and upper thorax. The internal jugular vein (IJV) is formed by the union of the sigmoid and inferior petrosal sinuses, which are joined by the common facial vein. The right and left IJVs course with the common carotid artery and vagus nerve inside the carotid sheath and provide venous drainage for the brain, face, and neck. They join their subclavian vein counterparts medially to form the right and left brachiocephalic veins, which in turn join to form the superior vena cava (SVC). The external jugular veins (EJVs) are formed by the union of the posterior retromandibular vein and posterior auricular vein. They course superficial to the sternocleidomastoid muscle and drain into the subclavian vein more laterally than do the IJVs. EJVs provide venous drainage for the exterior of the cranium and deep parts of the face. (Bottom) Coronal reformatted CT venogram shows normal cervicothoracic venous anatomy. IJV begins at the jugular foramen at the skull base. Its inferior course is lateral to the carotid arteries. IJVs and EJVs have a relatively superficial course and are thus susceptible to damage but are also easily accessible for venous catheterization. P.13:8

ANATOMY OF THORACIC VEINS, SVC, AND TRIBUTARIES

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(Top) Graphic shows normal anatomy of thoracic veins. The internal jugular and subclavian veins join bilaterally to form the right and left brachiocephalic or innominate veins that join to form the SVC, which courses behind the manubrium and sternum to enter the right atrium. The azygos, hemiazygos, and accessory hemiazygos veins connect the SVC and IVC. They course along the right & left sides of the upper lumbar and thoracic spine and drain the posterior abdomen and thorax. The azygos vein ascends on the right and drains into SVC above the level of the right mainstem bronchus. The hemiazygos vein ascends on the left and crosses to the right, posterior to the aorta, thoracic duct, and esophagus to join the azygos vein. The accessory hemiazygos vein descends on the left and may join the hemiazygos vein or cross to the right to join the azygos vein. (Bottom) DSA venogram in a patient with SVC stenosis shows the anatomy of SVC and some of its tributaries. The right & left brachiocephalic veins join to form the SVC, which drains into the right atrium to return venous blood from the head, neck, and upper extremities. The azygos vein ascends from the abdomen in the posterior mediastinum and arches over the right mainstem bronchus to join the SVC. P.13:9

ANATOMIC VARIANTS OF IVC

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(Top) Graphic shows 2 anatomic IVC variants, with insets demonstrating cross-sectional anatomy at various levels. In panel 1, the infrarenal IVC is completely left sided (insets C and D) and enters the left renal vein, which then crosses to the right (inset B). The left renal vein may cross anterior to the aorta or may be retroaortic, as in this example. Above the renal veins, the IVC is in a normal right-sided location. Panel 2 shows a duplicated IVC. There is a normal rightsided moiety (insets A-D). The left-sided moiety has the same anatomy as a solitary left-sided IVC as the cava ascends on the left to drain into the left renal vein (inset B). The left renal vein then crosses to the right, and the suprarenal IVC is in a normal right-sided location (inset A). (Bottom) Duplication of the IVC results from persistence of both supracardinal veins and has a reported prevalence of 0.2-3%. Cross-sectional CECT (panel 3) typically shows large venous structures paralleling the abdominal aorta on either side. Contrast venography (panel 4) shows that the leftsided caval moiety drains into the left renal vein while the right component ascends normally.

Superior Vena Cava Syndrome Superior Vena Cava Syndrome Brett W. Carter, MD Gerald F. Abbott, MD Key Facts Terminology Superior vena cava (SVC) obstruction by intraluminal, intramural, or extrinsic disease Impaired venous return from head, neck, upper extremities, and trunk to right atrium Imaging Radiography 1061

Diagnostic Imaging Cardiovascular May be normal Mediastinal widening Mediastinal/paramediastinal mass CT and MR Nonopacification of SVC on CT and MR Extrinsic compression by mass or lymphadenopathy Intraluminal filling defect Multiple collateral vessels Top Differential Diagnoses Thoracic outlet syndrome Brachiocephalic vein occlusion or stenosis Thrombosis, stenosis, or occlusion of deep upper extremity veins Persistent left SVC with absent right SVC Pathology Malignant etiologies (80-90%): Lung cancer, metastatic disease, lymphadenopathy, lymphoma Benign etiologies (10-20%): Granulomatous disease, iatrogenic, previous radiation therapy Clinical Issues SVC syndrome is a clinical diagnosis Face, neck, upper trunk, and upper extremity edema are the most common symptoms Diagnostic Checklist Consider SVC syndrome when patient with known malignancy develops typical signs and symptoms

(Left) Graphic demonstrates obstruction of the superior vena cava secondary to mediastinal invasion by a lung tumor . Note the distended brachiocephalic vein and right intercostal collateral vessel . (Right) Composite image with posteroanterior chest radiograph (left) and coronal CECT (right) of a patient with an indwelling right port catheter and hemodialysis catheter demonstrates thrombus within the superior vena cava.

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(Left) Axial CECT of a patient with small cell lung cancer invading the mediastinum shows complete obstruction of the superior vena cava. Note the collateral vessels in the left mediastinum and left posterior chest wall . (Right) Coronal CECT of the same patient demonstrates complete obstruction of the superior vena cava and the presence of collateral vessels in the left mediastinum and left chest wall . P.13:11

TERMINOLOGY Abbreviations Superior vena cava (SVC) Definitions Obstruction of SVC due to intraluminal, intramural, or extrinsic disease Impaired venous return from head, neck, upper extremities, and trunk to right atrium IMAGING General Features Best diagnostic clue Nonopacification of SVC Multiple collateral vessels Radiographic Findings Radiography May be normal Most common in mediastinal fibrosis Iatrogenic SVC obstruction Widened mediastinum Dilated SVC Mediastinal mass or lymphadenopathy Right hilar or paramediastinal mass Lung cancer Metastatic disease Lymphadenopathy of other etiology Enlarged azygos arch and vein CT Findings CECT Nonopacification of SVC Obstruction Extrinsic compression by mass or lymphadenopathy Intraluminal thrombus Multiple collateral vessels Neck, chest wall, mediastinum Enlarged mediastinal vessels Azygos arch and vein 1063

Diagnostic Imaging Cardiovascular Superior intercostal veins Brachiocephalic veins Inflow of contrast-enhanced blood into inferior vena cava Intense hepatic enhancement in quadrate lobe MR Findings T1WI C+ Evaluation of adjacent structures and causes of external SVC compression MRV Nonopacification of SVC Enlarged azygos arch and vein Multiple collateral vessels Neck, chest wall, and mediastinum Ultrasonographic Findings Grayscale ultrasound Dilatation of visualized SVC Stable lumen size with respiration or cardiac cycle Echogenic intraluminal thrombus Distended subclavian, brachiocephalic, and jugular veins Pulsed Doppler Altered spectral waveforms when evaluating subclavian veins Absent normal transmission of atrial waveform, respiratory phasicity, or response to provocative maneuvers Monophasic antegrade flow Low-velocity flow Color Doppler Sluggish or absent blood flow Angiographic Findings DSA Venography is performed when cross-sectional imaging is nondiagnostic Performed superior or peripheral to obstruction Stasis or retrograde flow in subclavian or brachiocephalic veins May mimic subclavian or brachiocephalic vein occlusion Extrinsic compression by mass or lymphadenopathy Effacement of SVC Indwelling catheters and pacemaker leads Long, smooth narrowing Intraluminal filling defect representing thrombus No intraluminal contrast = occlusion Multiple collateral vessels Azygos arch and vein enlargement Nuclear Medicine Findings Radionuclide uptake in liver “Hot quadrate” sign Radionuclide venography with Tc-99m microaggregated albumin Generated time-activity curves can show evidence of SVC obstruction Multiple collateral vessels Imaging Recommendations Best imaging tool CT and MR for optimal demonstration of nonopacification of SVC Evaluation of adjacent mediastinal structures Venography is useful for planning endovascular or surgical procedures Protocol advice Coronal and sagittal reformations to visualize site and extent of obstruction DIFFERENTIAL DIAGNOSIS Thoracic Outlet Syndrome Multiple collateral vessels in neck and upper chest Focal narrowing at junction of clavicle and 1st rib Patent SVC on contrast-enhanced imaging studies Brachiocephalic Vein Occlusion or Stenosis 1064

Diagnostic Imaging Cardiovascular Multiple collateral vessels in neck and upper chest Stenosis or occlusion of brachiocephalic vein Patent SVC on contrast-enhanced imaging studies P.13:12

Thrombosis, Stenosis, or Occlusion of Deep Upper Extremity Veins Usually secondary to indwelling catheters or pacemaker leads Multiple collateral vessels Upper extremity swelling may mimic SVC obstruction Patent SVC and central veins on contrast-enhanced imaging studies Persistent Left Superior Vena Cava With Absent Right Superior Vena Cava No collateral vessels No SVC in right superior mediastinum on imaging studies Aberrant course of catheters and pacemaker leads Course along left mediastinum Opacified venous structure in left superior mediastinum on imaging studies Terminates within coronary sinus Dilated coronary sinus PATHOLOGY General Features Etiology Intrathoracic malignancy Lung cancer (most common) Metastatic disease Breast, renal, and testicular cancers (most common) Mediastinal lymphadenopathy and lymphoma Primary mediastinal mass Granulomatous disease Infection Tuberculosis Histoplasmosis Sarcoidosis Silicosis Iatrogenic Indwelling catheters and pacemaker leads Previous radiation therapy Pyogenic infection Compression by mediastinal vascular lesion CLINICAL ISSUES Presentation Most common signs/symptoms Edema Face, neck, upper trunk, and upper extremities Headaches Dyspnea, dysphagia, hoarseness Palpable subcutaneous collateral vessels Neck and chest wall Other signs/symptoms Syncope, seizures, visual changes Coma in severe cases Clinical profile SVC syndrome is a clinical diagnosis Patients with well-compensated stenosis or occlusion may be asymptomatic Demographics Age Range: 18-76 years Mean: 54 years Malignant etiologies 1065

Diagnostic Imaging Cardiovascular Older, 40-60 years Benign etiologies Younger, 30-40 years Gender Malignant etiologies: M > F Benign etiologies: M = F Epidemiology Malignancy: Etiology in 80-90% Benign causes: Etiology in 10-20% 50% due to mediastinal fibrosis Recent increase in iatrogenic etiologies Most common benign cause in cancer patients Natural History & Prognosis Gradual, progressive obstruction of SVC Insidious onset of symptoms Survival depends on course of underlying disease Benign etiologies Rarely fatal Malignant etiologies Usually not cause of death Most die from metastatic malignancy Survival correlates with tumor histology Treatment Malignant etiologies Radiation therapy Chemotherapy targeted toward type of neoplasm Anticoagulation Endovascular therapy Catheter-directed thrombolysis Endovascular stent placement Surgical therapy Venous bypass Venous transposition DIAGNOSTIC CHECKLIST Consider SVC syndrome when patient with known malignancy develops typical signs and symptoms Image Interpretation Pearls Nonopacification of SVC Multiple collateral vessels in neck, chest wall, and mediastinum SELECTED REFERENCES 1. Eren S et al: The superior vena cava syndrome caused by malignant disease. Imaging with multi-detector row CT. Eur J Radiol. 59(1):93-103, 2006 2. Kalra M et al: Open surgical and endovascular treatment of superior vena cava syndrome caused by nonmalignant disease. J Vasc Surg. 38(2):215-23, 2003 3. Kim HJ et al: CT diagnosis of superior vena cava syndrome: importance of collateral vessels. AJR Am J Roentgenol. 161(3):539-42, 1993 4. Parish JM et al: Etiologic considerations in superior vena cava syndrome. Mayo Clin Proc. 56(7):407-13, 1981 5. Webb WR et al: Catheter venography in the superior vena cava syndrome. AJR Am J Roentgenol. 129(1):146-8, 1977 P.13:13

Image Gallery

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(Left) PA radiograph shows an irregular mass-like opacity in the right upper lobe in a patient with small cell lung cancer. (Right) Coronal CECT of the same patient demonstrates a small cell carcinoma of the right upper lobe invading the mediastinum and superior vena cava. Note the intense opacification of the right brachiocephalic vein with contrast material and the presence of collateral vessels in the mediastinum and right chest wall .

(Left) Axial CECT of a patient with head and neck cancer demonstrates mediastinal lymphadenopathy that results in occlusion of the superior vena cava . Collateral vessels are present in the left mediastinum and left posterior chest wall . Note the metastasis in the left lung . (Right) Composite image with axial CECT (left) and coronal CECT (left) shows occlusion of the superior vena cava . Note the distended azygos vein with retrograde flow of contrast material.

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(Left) Coronal CECT of a patient with squamous cell carcinoma of the right upper lobe shows complete atelectasis of the right upper lobe . Note the invasion of the right mediastinum and the superior vena cava . (Right) Axial CECT of the same patient demonstrates extensive collateral vessel formation in the mediastinum and left chest wall .

Inferior Vena Cava Anomalies Inferior Vena Cava Anomalies Sanjeeva P. Kalva, MBBS, MD, FSIR Key Facts Imaging Duplication of inferior vena cava (IVC) (double IVC) Left and right IVC inferior to renal veins Left IVC Ends at left renal vein, which crosses anterior to aorta in normal fashion, uniting with right renal vein to form normal right suprarenal IVC Azygos continuation of IVC IVC passes posterior to diaphragmatic crus to enter thorax as azygos vein May be isolated or associated with heterotaxy syndromes (asplenia or polysplenia) or congenital heart disease Other abnormalities Circumaortic or retroaortic left renal vein Duplication of IVC with retroaortic right renal vein and hemiazygos continuation of IVC Duplication of IVC with retroaortic left renal vein and azygos continuation of IVC Circumcaval, retrocaval, or transcaval ureter Absence of infrarenal or entire IVC External and internal iliac veins join to form enlarged ascending lumbar veins ± suprarenal IVC formed by left and right renal veins Venography is most accurate method for diagnosis and demonstrates course of major abdominal venous drainage Differentiate from varices and collateral veins Diagnostic Checklist Duplication of IVC should be suspected in recurrent pulmonary embolism following IVC filter placement Important to recognize IVC anomalies for certain interventional procedures (e.g., IVC filters, varicocele sclerotherapy, venous renal or adrenal sampling)

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(Left) Graphic shows the anatomy and cross-sectional appearance of circumaortic renal vein on the left and retroaortic renal vein on the right. (Right) The left image shows a left inferior vena cava (IVC). The infrarenal IVC is to the left of the aorta. The right image shows a duplicated IVC. The right common iliac vein continues as the right IVC, and the left common iliac as the left IVC. The left IVC joins the left renal vein, which in turn joins the right IVC. The left renal vein may be retroaortic or anterior to the aorta.

(Left) Coronal CTV shows a retroaortic left renal vein . Note the downward course of the retroaortic renal vein joining the IVC at a lower level than normal. (Right) Axial CTV shows a circumaortic left renal vein. The left renal vein divides into 2 components, one that runs anterior to the aorta and one that runs posterior to the aorta. These 2 components may join the IVC separately or as one. When they join separately, the retroaortic component runs inferiorly and joins the IVC at a lower level. P.13:15

TERMINOLOGY Definitions Congenital anomalies of inferior vena cava (IVC) IMAGING General Features Best diagnostic clue Malposition or duplication of IVC inferior to renal veins Types of IVC anomalies Duplication of IVC (double IVC) Left IVC 1069

Diagnostic Imaging Cardiovascular Azygos continuation of IVC Circumaortic left renal vein Retroaortic left renal vein Duplication of IVC with retroaortic right renal vein and hemiazygos continuation of IVC Duplication of IVC with retroaortic left renal vein and azygos continuation of IVC Circumcaval, retrocaval, or transcaval ureter Absence of infrarenal or entire IVC CT Findings Duplication of IVC Left and right IVC inferior to renal veins Usually, left IVC ends at left renal vein, which crosses anterior to aorta in normal fashion to join right IVC Left and right IVC may have significant size asymmetry Left IVC Left IVC ends at left renal vein, which crosses anterior to aorta in normal fashion, uniting with right renal vein to form normal right suprarenal IVC ↑ enhancement of right renal vein relative to left renal vein (dilution from unenhanced venous return from lower extremities) Azygos continuation of the IVC (absence of hepatic segment of IVC with azygos continuation) IVC passes posterior to diaphragmatic crus to enter thorax as azygos vein Azygos vein joins superior vena cava at normal location in right peribronchial location Hepatic veins drain directly into right atrium, and intrahepatic IVC is absent Enlarged azygos vein is similar in attenuation to superior vena cava Gonadal veins drain to ipsilateral renal veins Duplication of IVC with retroaortic right renal vein and hemiazygos continuation of IVC Left and right IVC inferior to renal vein Right IVC ends at right renal vein, which crosses posterior to aorta to join left IVC Suprarenal IVC passes posterior to diaphragmatic crus to enter thorax as hemiazygos vein In thorax, hemiazygos vein may Cross posterior to aorta at T8-T9 to join azygos vein Continue superiorly to join coronary vein of heart via persistent left superior vena cava Continue as accessory hemiazygos vein and join left innominate vein Duplication of IVC with retroaortic left renal vein and azygos continuation of IVC Mixture of findings previously mentioned Circumaortic left renal vein (common variant) 2 left renal veins Superior renal vein joined by left adrenal vein and crosses aorta anteriorly Inferior renal vein (1-2 cm below superior renal vein) joined by left gonadal vein and crosses aorta posteriorly Retroaortic left renal vein 1 left renal vein that crosses aorta posteriorly Circumcaval ureter Proximal ureter courses posterior to IVC, emerges to right of aorta and lies anterior to right iliac vessels Absence of infrarenal or entire IVC External and internal iliac veins join to form enlarged ascending lumbar veins Venous return from lower extremities to azygos and hemiazygos vein via anterior paravertebral collateral veins ± suprarenal IVC formed by left and right renal veins May be acquired abnormality following thrombosis of IVC MR Findings Flow voids or flow-related enhancement may distinguish aberrant vessels from masses Other findings similar to CT Ultrasonographic Findings Hepatic veins drain directly into right atrium when intrahepatic IVC is absent Duplicated IVC may be detected as 2 IVCs adjacent to aorta on either side Angiographic Findings Venography is most accurate method for diagnosis and demonstrates course of major abdominal venous drainage Imaging Recommendations Best imaging tool 1070

Diagnostic Imaging Cardiovascular CECT; consider multiplanar reformations Venous phase imaging is key for diagnosis DIFFERENTIAL DIAGNOSIS Retroperitoneal Lymphadenopathy Metastases, lymphoma, granulomatous disease Left-sided paraaortic adenopathy may mimic duplication of IVC or left IVC Differentiate by renal vein drainage or contrast-enhancement of IVC Presence of normal iliac vein confluence excludes duplication of IVC Retrocrural adenopathy may mimic enlarged azygos vein in retrocrural space Differentiate by tubular structure of azygos vein extending from diaphragm to azygos arch Retrocrural adenopathy lacks enhancement Retroperitoneal adenopathy may mimic circumaortic left renal vein Varices/Collaterals Seen in cirrhosis, IVC obstruction P.13:16

Gonadal Vein May appear as paraaortic soft tissue “mass” or mimic left-sided IVC Follow inferiorly: Does not “join” left iliac vein PATHOLOGY General Features Etiology Duplication of IVC Persistence of both supracardinal veins Left-sided IVC Regression of right supracardinal vein with persistence of left supracardinal vein Azygos continuation of the IVC Failure to form right subcardinal-hepatic anastomosis with resulting atrophy of right subcardinal vein May be associated with congenital heart disease and heterotaxy syndromes (asplenia or polysplenia) Circumaortic left renal vein Persistence of dorsal limb of embryonic left renal vein and of dorsal arch of renal collar (intersupracardinal anastomosis) Retroaortic left renal vein Persistence of dorsal arch of renal collar and regression of ventral arch (intersubcardinal anastomosis) Duplication of IVC with retroaortic right renal vein and hemiazygos continuation of IVC Persistence of left lumbar and thoracic supracardinal vein and left suprasubcardinal anastomosis Failure to form right subcardinal-hepatic anastomosis IVC duplication and azygos continuation with retroaortic left renal vein Persistent left supracardinal vein and dorsal limb of renal collar Regression of ventral arch and failure forming subcardinal-hepatic anastomosis Genetics Congenital with first-degree relatives as risk factor Associated abnormalities Association with congenital abnormalities such as horseshoe kidney, congenital heart disease, heterotaxy syndromes has been described Embryology 6th-8th gestational weeks: Infrahepatic IVC develops from appearance and regression of 3 paired embryonic veins (i.e., postcardinal, subcardinal, and supracardinal veins) Normal IVC is composed of hepatic, suprarenal, renal, and infrarenal segments Hepatic segment develops from vitelline vein Suprarenal segment develops from right subcardinal vein through subcardinal-hepatic anastomosis Renal segment develops from right suprasubcardinal and post-subcardinal anastomoses Infrarenal segment develops from right supracardinal vein In thorax, supracardinal veins form azygos and hemiazygos veins 1071

Diagnostic Imaging Cardiovascular In abdomen, subcardinal and supracardinal veins progressively replace postcardinal veins In pelvis, postcardinal veins form common iliac veins CLINICAL ISSUES Presentation Most common signs/symptoms Asymptomatic Circumcaval ureter: Partial right ureteral obstruction or recurrent urinary tract infections Absence of infrarenal or entire IVC: Venous insufficiency of lower extremities or idiopathic deep venous thrombosis Diagnosis Usually incidentally diagnosed by imaging Demographics Epidemiology Prevalence Duplication of IVC: 0.2-3% of general population Left IVC: 0.2-0.5% Azygos continuation of IVC: 0.6% Circumaortic left renal vein: 8.7% Retroaortic left renal vein: 2.1% Treatment Usually no treatment Circumcaval ureter: Surgical relocation of ureter anterior to IVC DIAGNOSTIC CHECKLIST Consider Duplication of IVC should be suspected in recurrent pulmonary embolism following IVC filter placement Image Interpretation Pearls Preoperative imaging may be important in planning abdominal surgery, liver or kidney transplantation Important to recognize IVC anomalies in certain interventional procedures (e.g., IVC filters, varicocele sclerotherapy, venous renal or adrenal sampling) SELECTED REFERENCES 1. Ichikawa T et al: Major venous anomalies are frequently associated with horseshoe kidneys. Circ J. 75(12):2872-7, 2011 2. Basile A et al: Embryologic and acquired anomalies of the inferior vena cava with recurrent deep vein thrombosis. Abdom Imaging. 28(3):400-3, 2003 3. Yilmaz E et al: Interruption of the inferior vena cava with azygos/hemiazygos continuation accompanied by distinct renal vein anomalies: MRA and CT assessment. Abdom Imaging. 28(3):392-4, 2003 4. Brochert A et al: Unusual duplication anomaly of the inferior vena cava with normal drainage of the right IVC and hemiazygous continuation of the left IVC. J Vasc Interv Radiol. 12(12):1453-5, 2001 5. Bass JE et al: Spectrum of congenital anomalies of the inferior vena cava: cross-sectional imaging findings. Radiographics. 20(3):639-52, 2000 6. Mayo J et al: Anomalies of the inferior vena cava. AJR Am J Roentgenol. 140(2):339-45, 1983 P.13:17

Image Gallery

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(Left) Graphic demonstrates a duplicated IVC. The right common iliac vein continues as the right IVC , whereas the left common iliac vein continues as the left IVC . The left IVC joins the left renal vein and crosses the aorta joining the IVC. The suprarenal IVC is normal and on the right. (Right) AP venography with 2 catheters positioned in the iliac veins shows a duplicated IVC with the left IVC joining the left renal vein , which in turn joins the right IVC , forming the normal suprarenal IVC . Note that the common iliac veins do not communicate in this anomaly.

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(Left) Sagittal CT reconstruction shows a normal infrarenal IVC that is formed by the confluence of both common iliac veins. At the level of the renal veins, the IVC continues as the azygos vein and runs retrocrurally along the right side of the thoracoabdominal aorta. The azygos joins the superior vena cava. (Right) Axial CECT shows a duplicated IVC formed through continuation of the iliac veins . Suprarenal IVC is absent as there is no IVC in the liver. Instead, the IVC continues as azygos vein retrocrurally and adjacent to the aorta in the thorax and joins the superior vena cava.

Inferior Vena Cava Occlusion Inferior Vena Cava Occlusion Sanjeeva P. Kalva, MBBS, MD, FSIR Key Facts Terminology Obstruction or occlusion of inferior vena cava from acute or chronic thrombosis or extrinsic compression Imaging Intraluminal filling defect (thrombus) within inferior vena cava (IVC) in acute occlusion Small IVC with multiple retroperitoneal collaterals in chronic occlusion Infrarenal IVC more often involved in occlusive processes than suprarenal IVC Top Differential Diagnoses Primary tumor of IVC Tumor extension into IVC Inflow of unopacified blood Congenital anomalies of IVC Clinical Issues Acute occlusion Pain and swelling of both lower extremities Subacute or chronic occlusion Asymptomatic if sufficient venous collaterals 1074

Diagnostic Imaging Cardiovascular Swelling of lower extremities Venous stasis dermatitis and venous ulcers Treatment Anticoagulation with heparin or warfarin IVC filter placement Catheter-directed thrombolysis Surgical thrombectomy or bypass Diagnostic Checklist Acute thrombus on ultrasound can be anechoic and can be missed on grayscale ultrasound Delayed CT is useful to assess and correctly diagnose thrombus in IVC and its extent

(Left) Coronal CECT of the abdomen in a patient with acute bilateral lower extremity swelling shows dilated inferior vena cava (IVC) and iliac veins with nonenhancing intraluminal filling defect , consistent with acute IVC and iliac vein thrombosis. (Right) Coronal contrast-enhanced MR venography shows signal-void, nonenhancing, dilated IVC and iliac veins consistent with acute thrombosis. Faint rim enhancement of the caval wall is also seen and may be due to vasa vasora.

(Left) Axial CECT of the abdomen shows intraluminal filling defect within the IVC surrounded by contrast, suggesting partial thrombosis of the IVC. It is important to get delayed-phase CECT in these patients to differentiate true thrombus from admixture of unopacified blood. (Right) AP venography through a catheter positioned in the right iliac vein shows multiple intraluminal filling defects within the IVC and IVC filter , consistent with partial thrombosis of the IVC and IVC filter. P.13:19

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Diagnostic Imaging Cardiovascular TERMINOLOGY Abbreviations Inferior vena cava (IVC) occlusion Synonyms IVC obstruction Definitions Obstruction or occlusion of inferior vena cava from acute or chronic thrombosis or extrinsic compression IMAGING General Features Best diagnostic clue Intraluminal filling defect (thrombus) within IVC in acute occlusion Small IVC with multiple retroperitoneal collaterals in chronic occlusion Location Infrarenal IVC more often involved in occlusive processes than suprarenal IVC Thrombus generally propagates cephalad into IVC from iliac veins In situ thrombus in IVC is secondary to foreign body (filter) or extrinsic compression (IVC clip or mass) Size Diameter of IVC varies with respiration and blood volume Mean diameter of normal infrarenal IVC is 20 mm (range: 13-30 mm) Mega cava refers to diameters > 30 mm Most current filters approved for IVC diameter of 28-30 mm except for bird's nest filter, which is approved for IVC diameter up to 40 mm Ultrasonography Acute thrombus Presence of thrombus in IVC Distension of IVC Echogenicity varies with age: Fresh thrombus is anechoic or hypoechoic; subacute to chronic thrombus is hyperechoic Tongue-like projection at tip of thrombus suggests free-floating clot Absence of color flow if complete thrombus Peripheral rim of flow if incomplete thrombus Distal to occluding thrombus, Doppler may show absence of respiratory flow variations in IVC Chronic occlusion Difficult to evaluate with ultrasound Absent or small-caliber IVC Multiple vessels in normal location of IVC may represent partially recanalized thrombus Multiple retroperitoneal collaterals CT Acute thrombus Distended IVC with complete or partial thrombus Fresh thrombus hyperdense on non-contrast CT Thrombus surrounded by contrast material on CECT indicates partial IVC thrombosis Associated extrinsic compression from mass may be seen Enhancement of wall with distension of IVC suggest intrinsic obstruction with thrombus Enhancement of thrombus suggests tumor thrombus Thrombus in filter best assessed with CT Extrinsic compression due to lymph nodes or mass can be seen Best examination to assess extent of thrombus Chronic occlusion Small or absent IVC Commonly affects infrarenal IVC and iliac veins Multiple retroperitoneal collaterals MR Findings similar to CT Chronic occlusion better appreciated on contrast-enhanced MR venography Intravascular ultrasound Useful to accurately assess extent of mural thrombus in partial thrombosis Angiography 1076

Diagnostic Imaging Cardiovascular Acute thrombus Filling defect on venacavography Extent, size, and involvement of tributaries can be assessed Inflow from renal veins should be differentiated from thrombus Catheter injection should be performed at site of suspected thrombus/stenosis Chronic thrombus Small caliber IVC with multiple retroperitoneal collaterals Stenosis of IVC Imaging Recommendations Best imaging tool Contrast-enhanced CT/MR Protocol advice Delayed imaging at 90-120 seconds after contrast administration useful to accurately diagnose extent of thrombosis DIFFERENTIAL DIAGNOSIS Primary Tumor of IVC Sarcoma or leiomyomatosis Enhancement of the thrombus Tumor Extension Into IVC From renal cell carcinoma, adrenal cortical carcinoma, hepatocellular carcinoma, uterine sarcoma, or retroperitoneal sarcomas Continuity of mass with primary tumor Enhancement of thrombus Inflow of Unopacified Blood Inflow from renal veins may mimic thrombus on CT or angiography Angiography: Filling defect from renal vein inflow changes with each image frame and is not consistent CECT: Central filling defect in IVC due to rapid inflow of contrast-enhanced blood from renal veins and unopacified blood from lower extremities Delayed imaging helpful for differentiation P.13:20

Congenital Anomalies of IVC Congenital absence of IVC with azygos continuation Left IVC PATHOLOGY General Features Etiology Intrinsic Thrombus extending from lower extremities Hypercoagulable states Primary tumor of IVC: Leiomyomatosis, sarcoma Secondary tumor extension from renal cell carcinoma, hepatoma, retroperitoneal sarcoma, adrenal carcinoma Congenital membrane of IVC Extrinsic Enlarged lymph nodes from neoplasm or infection Retroperitoneal mass (e.g., neoplasm, hematoma) Aortic aneurysm Retroperitoneal fibrosis Pregnancy Hepatomegaly Surgical ligation or plication of IVC Associated abnormalities May-Thurner syndrome Congenital anomalies of IVC CLINICAL ISSUES Presentation Most common signs/symptoms 1077

Diagnostic Imaging Cardiovascular Acute occlusion Pain and swelling of both lower extremities Severe cases: Phlegmasia Hypotension Subacute or chronic occlusion Asymptomatic if sufficient venous collaterals Multiple collaterals may be present in anterior abdominal wall Swelling of lower extremities Venous stasis dermatitis Chronic venous ulcers Other signs/symptoms May rarely be the cause of Budd-Chiari syndrome (hepatic vein occlusion) Treatment Anticoagulation with heparin or warfarin IVC filter placement Indicated in Inability to anticoagulate (contraindication to or failure/complication from anticoagulation) Severe pulmonary artery hypertension Filter placed in infrarenal IVC above thrombus Suprarenal IVC filter if thrombosis extends to renal vein level or involves renal or gonadal veins Acute thrombosis of IVC may result from filter catching a massive embolus Catheter-directed thrombolysis Pharmacological or mechanical or pharmacomechanical thrombolysis using thrombolytic drugs (t-PA) May be supplemented with intravascular stent placement following successful thrombolysis Surgery Surgical thrombectomy Surgical bypass IVC ligation IVC plication or IVC clip placement Treatment of extrinsic compression as cause of IVC obstruction or occlusion Surgical resection of tumor or mass Radiotherapy or chemotherapy of adenopathy or tumor Stent placement in IVC DIAGNOSTIC CHECKLIST Consider Catheter-directed thrombolysis with t-PA, followed by intravascular stents for acute thrombosis in severely symptomatic patient Image Interpretation Pearls Acute thrombus on ultrasound can be anechoic and can be missed on grayscale ultrasound Delayed CT useful to assess and correctly diagnose thrombus in IVC and its extent Abdominal wall collaterals can be due to superior vena cava obstruction, IVC obstruction, or portal venous hypertension SELECTED REFERENCES 1. Hajduk B et al: Vena cava filter occlusion and venous thromboembolism risk in persistently anticoagulated patients: a prospective, observational cohort study. Chest. 137(4):877-82, 2010 2. Delis KT et al: Successful iliac vein and inferior vena cava stenting ameliorates venous claudication and improves venous outflow, calf muscle pump function, and clinical status in post-thrombotic syndrome. Ann Surg. 245(1):130-9, 2007 3. Koc Z et al: Interruption or congenital stenosis of the inferior vena cava: prevalence, imaging, and clinical findings. Eur J Radiol. 62(2):257-66, 2007 4. Ushijima T et al: Successful surgical treatment of chronic inferior vena caval thrombosis following blunt trauma. Gen Thorac Cardiovasc Surg. 55(6):255-8, 2007 5. Healey CT et al: Endovascular stenting of ascending lumbar veins for refractory inferior vena cava occlusion. J Vasc Surg. 44(4):879-81, 2006 6. Raju S et al: Obstructive lesions of the inferior vena cava: clinical features and endovenous treatment. J Vasc Surg. 44(4):820-7, 2006 7. te Riele WW et al: Endovascular recanalization of chronic long-segment occlusions of the inferior vena cava: midterm results. J Endovasc Ther. 13(2):249-53, 2006

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Diagnostic Imaging Cardiovascular 8. Yamada N et al: Pulse-spray pharmacomechanical thrombolysis for proximal deep vein thrombosis. Eur J Vasc Endovasc Surg. 31(2):204-11, 2006 9. Hilliard NJ et al: Leiomyosarcoma of the inferior vena cava: three case reports and review of the literature. Ann Diagn Pathol. 9(5):259-66, 2005 10. Robbins MR et al: Endovascular stenting to treat chronic long-segment inferior vena cava occlusion. J Vasc Surg. 41(1):136-40, 2005 11. Kazmers A et al: Duplex examination of the inferior vena cava. Am Surg. 66(10):986-9, 2000 12. Razavi MK et al: Chronically occluded inferior venae cavae: endovascular treatment. Radiology. 214(1):133-8, 2000 P.13:21

Image Gallery

(Left) Axial MR venography shows partial intraluminal filling defect within the IVC, consistent with partial thrombosis. Note enhancement of the caval wall, which is commonly seen in acute thrombosis. (Right) Axial CECT of the abdomen shows an IVC filter with peripheral murally adherent partial filling defect within the filter , consistent with subacute thrombosis of the caval filter.

(Left) AP venography through right common iliac venous injection shows narrowing of the IVC with associated filling defect and multiple retroperitoneal collaterals . These features are consistent with chronic subtotal IVC occlusion. (Right) AP venography through right iliac venous injection shows multiple retroperitoneal and paravertebral venous plexus of veins with no opacification of IVC. This is consistent with chronic complete occlusion of entire IVC.

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(Left) Coronal CECT of the abdomen shows an enlarged IVC with soft tissue filling mass within. Note enhancement of the mass and mass in the liver. This patient has a hepatocellular carcinoma that extended into the IVC. (Right) Oblique CECT shows thrombus in the IVC below the IVC filter . Also note extension of thrombus superior to the filter along the anterior wall of the IVC. Note that the thrombus does not enhance, suggesting that this is plain thrombus but not tumor thrombus.

Left Superior Vena Cava Key Facts Terminology Persistent left superior vena cava (PLSVC) Rare variant venous structure that drains blood from left upper extremity and head and neck region 80-90% drain into right atrium via coronary sinus 10-20% drain into left atrium (right-to-left shunt) Failure of regression of left anterior cardinal vein during embryological development Imaging Radiography Left-sided central venous catheter courses caudally, parallel to spine along left mediastinal border, into heart CT Rounded structure in left mediastinum lateral to aortic arch Courses caudally to the left of left main pulmonary artery and left atrium Joins dilated coronary sinus then right atrium Echocardiogram Should suspect PLSVC when dilated coronary sinus is visualized Top Differential Diagnoses Partial anomalous pulmonary venous return from left upper lobe Malpositioning of left central venous catheter Left internal mammary vein Left subclavian artery → descending aorta Clinical Issues Usually asymptomatic incidental finding on imaging or during central venous catheter placement Associated with congenital heart disease and arrhythmia Risk for paradoxical thromboembolism and air embolism if PLSVC drains into left atrium

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(Left) PA radiograph of a patient with implantable cardioverter-defibrillator placed via left subclavian approach shows the left mediastinal vertical course of the leads, which then course medially into the coronary sinus and right atrium . The right ventricle lead takes an acute loop in the right atrium to enter the right ventricle . (Right) Lateral radiograph shows the vertical course of the leads posterior to the left ventricle into the coronary sinus , then anteriorly into the right atrium and right ventricle .

(Left) Coronal oblique MIP reconstruction CECT of the same patient prior to the implantable cardioverter-defibrillator placement shows a bridging vein connecting the right internal jugular and subclavian veins to the left brachiocephalic vein to form a persistent left superior vena cava (PLSVC) , which drains into the coronary sinus and right atrium . (Right) Sagittal reformat CECT of a different patient shows the left superior vena cava coursing posterior to the left heart into the coronary sinus . P.13:23

TERMINOLOGY Abbreviations Superior vena cava (SVC) Synonyms Persistent left superior vena cava (PLSVC) Definitions Variant venous structure draining venous blood from the left upper extremity and head and neck region IMAGING General Features Size 1081

Diagnostic Imaging Cardiovascular Variable Similar in size to right SVC if bilateral SVC is present Larger if right SVC is absent Morphology Usually drains into dilated coronary sinus, then into right atrium Rarely drains into left atrium, constituting a right-to-left shunt If bilateral SVC is present, there may be absence of a communicating vein, a normal brachiocephalic vein, or ≥ 1 abnormal venous connections between right and left SVC Radiographic Findings Left-sided central venous catheter courses caudally, parallel to spine along left mediastinal border, into heart Usually not visible without catheter or pacemaker lead in PLSVC Crescentic opacity adjacent to aortic knob More caudally, opacity lateral to descending aorta CT Findings Axial images Round or oval structure in left mediastinum lateral to aortic arch Courses laterally to the left of left main pulmonary artery and medial to left superior pulmonary vein More inferiorly, to the left of left atrium Usually drains into dilated coronary sinus Eventually drains into right atrium Alternatively, can drain into left atrium Directly into superior aspect of left atrium Or through unroofed coronary sinus Or joins left superior pulmonary vein, then drains into left atrium Coronal and sagittal reformation Helpful to demonstrate drainage pattern Absent right SVC Bridging vein (right brachiocephalic) draining right jugular and subclavian veins, which joins left brachiocephalic vein to form left SVC May show bilateral SVC ± 1 or more bridging veins Ultrasonographic Findings Dilated coronary sinus on parasternal long-axis view PLSVC, diameter > 1 cm Should raise possibility of PLSVC in absence of elevated right-sided filling pressure Following contrast (agitated saline) injection into a left upper extremity vein Enhancement of dilated coronary sinus before right atrium confirms left SVC draining into coronary sinus Enhancement of left atrium instead of right atrium would suggest unroofed coronary sinus Following contrast injection into a right upper extremity vein Enhancement of right atrium before coronary sinus: Right SVC is present Enhancement of coronary sinus before right atrium: Right SVC is absent Helpful for detection of associated congenital cardiac anomalies if present Imaging Recommendations Best imaging tool Contrast-enhanced CT Angiographic Findings Contrast venography (can be performed in operating room with intraoperative fluoroscopy) Craniocaudally oriented venous structure coursing to the left of midline DIFFERENTIAL DIAGNOSIS Partial Anomalous Pulmonary Venous Return Left upper lobe partial anomalous pulmonary venous return appears also as rounded vascular structure in left mediastinum anterior to aortic arch Left upper lobe veins coalesce, ascend toward left brachiocephalic vein, and drain into it Normal left superior pulmonary vein is absent Left-to-right shunt Malpositioning of Left Central Venous Catheter Left mediastinal course of catheter on frontal radiograph is also seen with catheter in Left internal mammary vein Left superior intercostal and accessory hemiazygous veins Left subclavian artery to descending thoracic aorta 1082

Diagnostic Imaging Cardiovascular Extravascular space in left mediastinum Lateral radiograph or cross-sectional imaging is helpful to confirm catheter location Total Anomalous Pulmonary Venous Return, Supracardiac Type Posterior collecting vein Receives pulmonary veins Drains into a vertical vein (location similar to left SVC) With superiorly directed blood flow (opposite of left SVC) Vertical vein Drains into a dilated left brachiocephalic vein, which normally connects with right brachiocephalic vein to form dilated right SVC PATHOLOGY General Features Etiology P.13:24

Failure of regression of left anterior cardinal vein caudal to left brachiocephalic vein during embryological development Gross Pathologic & Surgical Features 80-90% PLSVC coexist with right SVC (double SVC) Left brachiocephalic vein is absent in ˜ 65% of these patients Right SVC drains into right atrium normally 10-20% of PLSVC have absent right SVC (isolated PLSVC) Right internal jugular and subclavian veins drain into a bridging vein, which joins left brachiocephalic vein to form PLSVC Nearly half of these patients have congenital cardiac abnormalities 80-90% of PLSVC drain into coronary sinus, then into right atrium 10-20% drain into left atrium directly or through unroofed coronary sinus or through left superior pulmonary vein Right-to-left shunt Potential for systemic thromboembolism or air embolism Medications delivered through catheter or left upper extremity vein enter systemic circulation Left superior intercostal vein can connect PLSVC with accessory hemiazygos vein to form left-sided azygous arch CLINICAL ISSUES Presentation Most common signs/symptoms Asymptomatic incidental finding on imaging for unrelated reasons Incidental finding during or after central venous catheter or pacemaker placement Demographics Epidemiology Most common congenital venous anomaly of thoracic systemic venous return 0.3-0.5% of general population 4-12% of patients with congenital cardiac anomalies have PLSVC Atrial septal defect Ventricular septal defect Coarctation of aorta Transposition of great vessels Tetralogy of Fallot Bicuspid aortic valve Cor triatriatum Anomalous pulmonary venous return Associated with arrhythmia and conduction abnormalities Possible mechanisms Dilated coronary sinus stretches atrioventricular nodal tissue → reentrant tachycardia Conduction tissue in close proximity to the cardinal vein during early development → sinus node dysfunction in PLSVC Associated with esophageal atresia Natural History & Prognosis Various reported complications when pacemaker leads or catheter are inserted via left subclavian vein Arrhythmia 1083

Diagnostic Imaging Cardiovascular Cardiac tamponade Cardiogenic shock Coronary sinus thrombosis Significant risk of paradoxical embolic events when PLSVC drains into left atrium Treatment Surgical correction in cases with large right-to-left shunt with PLSVC draining into left atrium Relative contraindication for retrograde cardioplegia administration during cardiac surgery Careful dissection of coronary sinus during cardiac transplant surgery to allow anastomosis of PLSVC to right atrium Considerations for Central Venous Access In the absence of right SVC Consider femoral vein access Left subclavian vein is still preferred access for pacemaker lead placement Acute angle between coronary sinus ostium and tricuspid valve Lead makes acute loop in right atrium to enter right ventricle DIAGNOSTIC CHECKLIST Image Interpretation Pearls Look for possible associated congenital cardiac anomalies when PLSVC is detected, particularly if right SVC is absent Reporting Tips When PLSVC detected, it is important to characterize venous return to right atrium or left atrium and also report right central venous anatomy SELECTED REFERENCES 1. Povoski SP et al: Persistent left superior vena cava: review of the literature, clinical implications, and relevance of alterations in thoracic central venous anatomy as pertaining to the general principles of central venous access device placement and venography in cancer patients. World J Surg Oncol. 9:173, 2011 2. Benson RE et al: CT appearance of persistent left superior vena cava, anomalous right superior pulmonary venous return into the right-sided superior vena cava and a sinus venosus-type atrial septal defect. Br J Radiol. 82(983):e2359, 2009 3. Dehghani P et al: Transcatheter closure of persistent left sided superior vena cava draining into left atrium importance of balloon test occlusion. J Invasive Cardiol. 21(7):E122-5, 2009 4. Goyal SK et al: Persistent left superior vena cava: a case report and review of literature. Cardiovasc Ultrasound. 6:50, 2008 5. Burney K et al: CT appearances of congential and acquired abnormalities of the superior vena cava. Clin Radiol. 62(9):837-42, 2007 P.13:25

Image Gallery

(Left) PA radiograph of a patient with PLSVC shows a subtle opacity with straight margin lateral to the aortic knob and descending aorta. (Right) Coronal reformat CECT confirms that the opacity seen on chest radiograph corresponds 1084

Diagnostic Imaging Cardiovascular to PLSVC , which courses lateral to the aortic arch and main pulmonary artery. The patient also has a right superior vena cava and anomalous right upper lobe pulmonary venous return draining into right superior vena cava .

(Left) Axial CECT shows PLSVC lateral to the left main pulmonary artery and medial to the left superior pulmonary vein . Note that in this patient the right superior vena cava is absent, so the PLSVC is large, draining blood from the head and neck and bilateral upper extremities. (Right) Axial CECT of the same patient shows a markedly dilated coronary sinus posterior to the left ventricle and draining into the right atrium .

(Left) Axial CECT of a patient with double superior vena cava shows the PLSVC located anterior to the aortic arch. The right superior vena cava is in its normal location in the right mediastinum. (Right) Coronal oblique reformat CECT of the same patient shows the PLSVC draining directly into the left atrium , resulting in right-to-left shunt. The right superior vena cava drains normally into the right atrium (not shown).

Azygos Continuation of the IVC Azygos Continuation of the IVC Jonathan Hero Chung, MD Key Facts Terminology Inferior vena cava (IVC) interrupted above renal veins Hepatic veins drain into right atrium; azygos vein carries venous return from lower extremities Imaging Radiography Focal enlargement of azygos arch in right tracheobronchial angle 1085

Diagnostic Imaging Cardiovascular Dilated if > 10 mm diameter in erect position Bilateral left lungs and bronchi with heterotaxy CT Absent suprarenal and intrahepatic portions of IVC Hepatic veins enter right atrium directly Dilated azygos courses upward and drains into superior vena cava Dilated hemiazygos in hemiazygos continuation Polysplenia heterotaxy syndrome Top Differential Diagnoses Azygos enlargement from superior vena cava obstruction Azygos enlargement from pulmonary artery hypertension Azygos enlargement from high-volume states Enlargement of azygos region lymph node Intrahepatic IVC occlusion by tumor/thrombus Clinical Issues Often asymptomatic Symptoms related to congenital heart disease Prognosis related to associated anomalies May be lethal if inadvertently ligated at surgery Diagnostic Checklist Difficulties may arise during catheter-based intervention through IVC, such as right heart catheterization

(Left) Graphic shows characteristic features of azygos continuation. The inferior vena cava is absent, the hepatic veins drain directly into the right atrium, and the azygos vein is enlarged and provides the main venous drainage below the diaphragm. Identification of azygos continuation is vital in surgical planning to avoid inadvertent surgical ligation of the azygos vein. (Right) PA chest radiograph shows enlargement of the azygos arch in a patient with azygos continuation of the inferior vena cava (IVC).

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(Left) Axial CECT of a patient with azygos continuation of the IVC shows an enlarged azygos vein arching over the right main stem bronchus and entering the superior vena cava. (Right) Axial CECT of the abdomen of the same patient shows the enlarged azygous vein and heterotaxy with a midline liver, a right-sided stomach , and polysplenia . Azygos continuation of the IVC is associated with heterotaxy syndrome. P.13:27

TERMINOLOGY Abbreviations Azygos continuation of inferior vena cava (IVC) Synonyms Interruption of IVC Absence of hepatic segment of IVC with azygos continuation Definitions IVC is interrupted above renal veins Hepatic veins drain directly into right atrium Large azygos vein carries venous return from lower extremities Occasionally, a large hemiazygos vein carries venous return Caused by persistence of embryonic right supracardinal vein and failure of development of suprarenal part of subcardinal vein Associated with congenital heart disease and situs abnormalities, especially polysplenia (heterotaxy syndrome) IMAGING General Features Best diagnostic clue Absence of intrahepatic segment of IVC with dilated azygos or hemiazygos vein on contrast-enhanced CT Size Azygos arch located in right tracheobronchial angle Dilated if > 10 mm short-axis diameter in erect position Dilated if > 15 mm short-axis diameter in supine position Radiographic Findings Posteroanterior Focal enlargement of azygos arch in right tracheobronchial angle Round or oval shape Considered dilated when > 10 mm diameter in erect position Considered dilated when > 15 mm diameter in supine position Visualization of azygos vein interface Visualization of aortic nipple may occur with hemiazygos continuation Bilateral left lungs and bronchi if associated with polysplenia Transverse or transposed liver if associated with polysplenia Lateral Thickening of retroesophageal stripe 1087

Diagnostic Imaging Cardiovascular Absence of retrocardiac IVC interface (sometimes) Suprahepatic portions of IVC may be present CT Findings CECT Absent suprarenal and intrahepatic portions of IVC Hepatic veins enter directly into right atrium Large posterior, paraspinal vessel corresponding to azygos (right) or hemiazygos (left) continuation Dilated azygos courses upward and drains into superior vena cava Look for dilated azygos arch Dilated hemiazygos courses upward Typically drains into a left superior vena cava with dilated coronary sinus May cross midline and join azygos vein Rarely drains to accessory hemiazygos, left superior intercostal, and left brachiocephalic veins Look for dilated left-sided venous arch lateral to aorta in typical drainage Polysplenia findings (heterotaxy) Multiple spleens Situs ambiguus Bilateral bilobed (left-sided morphology) lungs Bilateral hyparterial (left-sided morphology) bronchi Congenital heart disease Especially atrial septal defect or ventricular septal defect Midline or transposed abdominal viscera, intestinal malrotation, preduodenal portal vein, truncated pancreas MR Findings T1WI Absent suprarenal and intrahepatic portions of IVC Hepatic veins enter right atrium directly Large posterior, paraspinal vessel corresponding to azygos (right) or hemiazygos (left) continuation Dilated azygos courses upward and drains into superior vena cava Look for dilated azygos arch Dilated hemiazygos courses upward along left side of spine Typically drains into left superior vena cava with dilated coronary sinus May cross midline and join azygos Rarely drains to accessory hemiazygos vein, left superior intercostal vein, or left brachiocephalic vein Look for dilated left-sided venous arch lateral to aorta in typical drainage Polysplenia findings identical to CT findings Multiple spleens Situs ambiguus MRA Azygos continuation of interrupted IVC is observed on venous phase Imaging Recommendations Best imaging tool Contrast-enhanced CT is imaging study of choice to evaluate azygos continuation DIFFERENTIAL DIAGNOSIS Enlargement of Azygos Arch and Vein Due to Superior Vena Cava Obstruction Distal occlusion of superior vena cava by mass or thrombosis Azygos serves as collateral pathway Normal IVC P.13:28

Enlargement of Azygos Arch Due to Pulmonary Artery Hypertension Dilated right heart chambers and superior vena cava Enlarged central pulmonary arteries Normal IVC Enlargement of Azygos Arch Due to High-Volume States Enlarged heart and increased pulmonary vessels Normal or dilated IVC 1088

Diagnostic Imaging Cardiovascular Seen with pregnancy, sickle cell disease, or renal disease Enlargement of Azygos Region Lymph Node Azygos arch and vein are normal and separate from node Normal IVC Occlusion of Intrahepatic Inferior Vena Cava Due to Tumor or Thrombosis Liver mass, especially hepatocellular carcinoma, which grows intravascularly Normal infrahepatic IVC Double Aortic Arch Normal azygos arch and vein Normal IVC PATHOLOGY General Features Etiology Persistence of embryonic right supracardinal vein Failure of development of suprarenal part of subcardinal vein Genetics Sporadic Associated abnormalities Polysplenia Bilateral hyparterial bronchi Bilobed lungs Midline liver Multiple spleens Congenital heart disease Atrial septal defect Ventricular septal defect Rare in asplenia Gross Pathologic & Surgical Features Complicates surgical planning for Esophagectomy Liver transplantation IVC filter placement Abdominal aortic aneurysm repair CLINICAL ISSUES Presentation Most common signs/symptoms Often asymptomatic Often discovered incidentally Other signs/symptoms Symptoms related to congenital heart disease May be associated with sick sinus syndrome Demographics Age Variable Occurs early in life if associated with severe congenital heart disease Gender No predilection Epidemiology Prevalence < 0.6% 0.2-4.3% of cardiac catheterizations for congenital heart disease Natural History & Prognosis Related to associated anomalies, particularly congenital heart disease May be lethal if inadvertently ligated at surgery Treatment Related to associated anomalies, particularly congenital heart disease May complicate surgical procedures (e.g., liver transplantation) DIAGNOSTIC CHECKLIST Consider Difficulties may arise during catheter-based intervention through IVC, such as right heart catheterization 1089

Diagnostic Imaging Cardiovascular Image Interpretation Pearls Lateral chest radiograph may not show absence of retrocardiac IVC interface due to drainage of hepatic veins in that location SELECTED REFERENCES 1. Yildirim A et al: An unusual case of heterotaxy and polysplenia syndrome associated with hemiazygous continuation of the left-sided vena cava inferior, dilated azygous vein and large venous ectasia. Congenit Heart Dis. 6(3):262-5, 2011 2. Mamidipally S et al: Azygous continuation of inferior vena cava. J Am Coll Cardiol. 56(21):e41, 2010 3. Morita S et al: Pelvic venous variations in patients with congenital inferior vena cava anomalies: classification with computed tomography. Acta Radiol. 48(9):974-9, 2007 4. Bartram U et al: Heterotaxy syndrome — asplenia and polysplenia as indicators of visceral malposition and complex congenital heart disease. Biol Neonate. 88(4):278-90, 2005 5. Demos TC et al: Venous anomalies of the thorax. AJR Am J Roentgenol. 182(5):1139-50, 2004 6. Plata-Muñoz JJ et al: Polysplenia syndrome in the adult patient. Case report with review of the literature. Ann Hepatol. 3(3):114-7, 2004 7. Yilmaz E et al: Interruption of the inferior vena cava with azygos/hemiazygos continuation accompanied by distinct renal vein anomalies: MRA and CT assessment. Abdom Imaging. 28(3):392-4, 2003 8. Bass JE et al: Spectrum of congenital anomalies of the inferior vena cava: cross-sectional imaging findings. Radiographics. 20(3):639-52, 2000 9. Applegate KE et al: Situs revisited: imaging of the heterotaxy syndrome. Radiographics. 19(4):837-52; discussion 853-4, 1999 P.13:29

Image Gallery

(Left) Axial NECT shows an enlarged azygos vein in this case of azygos continuation of the IVC. Acquired obstruction of the IVC could also result in dilatation of the azygos vein and should be excluded. (Right) Axial NECT of the same patient shows the typical appearance of the enlarged azygos vein coursing alongside the descending aorta. Azygos continuation of the IVC is usually easily recognized on CT studies even in the absence of intravenous contrast.

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(Left) PA chest radiograph of a patient with azygos continuation shows an enlarged azygos vein and nonvisualization of the superior aspect of the azygoesophageal recess. (Right) Coronal NECT thick multiplanar reformation average shows the dilated azygos vein as it courses obliquely across the superior aspect of the azygoesophageal recess, explaining the obliteration of the superior aspect of the recess on frontal chest radiography.

(Left) Coronal minimum intensity projection (MinIP) reformation shows bilateral left-sided bronchi and an enlarged azygos arch in a patient with azygos continuation of the IVC. The lungs were bilobed (not shown). Airway anatomy is shown in high detail using thick MinIP reformatted images. (Right) Axial NECT of the same patient shows the dilated azygos vein coursing alongside the descending aorta and multiple left-sided spleens related to polysplenia .

May-Thurner Syndrome May-Thurner Syndrome Sanjeeva P. Kalva, MBBS, MD, FSIR Key Facts Terminology Compression of left common iliac vein (CIV) by right common iliac artery (CIA) Synonyms: Iliac vein compression syndrome, Cockett syndrome, iliocaval vein syndrome Imaging Extrinsic compression of left CIV by right CIA Presence of collaterals in pelvis crossing midline to join contralateral iliac veins and dilated ascending lumbar vein Time-of-flight MRV shows absence of flow in left internal iliac vein due to flow reversal and dilated ascending lumbar vein

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Diagnostic Imaging Cardiovascular Intravascular ultrasound can determine vessel size and internal wall morphology; may also demonstrate intraluminal spur and assist with treatment planning (stent placement) Left common femoral vein Doppler may show absence of respiratory variations suggesting proximal obstruction Top Differential Diagnoses Radiation, chemotherapy, and hormonal therapy Pelvic tumors Chronic deep venous thrombosis Clinical Issues Unilateral swelling, pain, and aching of left leg Venous stasis and ulcers Treatment options Standard: Anticoagulation, compression stockings Catheter-directed thrombolysis followed by endovascular intervention (balloon angioplasty and stenting) Surgery: Thrombectomy, direct surgical reconstruction or bypass, vein patch angioplasty

(Left) Coronal graphic image depicts the anatomic relationship of iliac vessels. The left common iliac vein lies between the right common iliac artery and the lumbosacral spine where it may be compressed, causing left deep venous thrombosis (DVT). (Right) Axial oblique TOF MRV shows occlusion of the left common iliac vein at its confluence with the right common iliac vein. Note normal patent right internal iliac vein . The left internal iliac vein is not visualized on this TOF MRV due to flow reversal.

(Left) Axial CE MRV shows compression of the left common iliac vein by the right common iliac artery against the lumbar spine. (Right) Axial CE MRV shows cross pelvic collateral veins . Note the patent left internal iliac vein , suggesting that its absence on TOF MRV is secondary to flow reversal and not due to thrombosis. Flow reversal in the left internal iliac vein on TOF MRV and the presence of pelvic collaterals on CE MRV suggest that the venous 1092

Diagnostic Imaging Cardiovascular compression is hemodynamically significant. P.13:31

TERMINOLOGY Synonyms Iliac vein compression syndrome (IVCS) Cockett syndrome Iliocaval vein syndrome Definitions Compression of left common iliac vein (CIV) by right common iliac artery (CIA) with associated left lower extremity deep venous thrombosis (DVT) IMAGING General Features Best diagnostic clue Young women with persistent left lower leg edema Location Left common iliac vein between right common iliac artery and spine CT Findings CECT Extrinsic compression of left CIV by right CIA Diameter of left CIV at site of compression is smaller than normal Presence of collaterals in pelvis crossing midline to join contralateral iliac veins Enlarged ascending lumbar vein with collaterals to vertebral plexus of veins Lower extremity DVT Tortuosity of aortoiliac arteries Mild to moderate degenerative changes in lumbar vertebrae and sacrum MR Findings MRV Time-of-flight (TOF) MRV shows absence of flow in left internal iliac vein due to flow reversal and dilated ascending lumbar vein Contrast-enhanced MRV shows area of compression or obstruction and pelvic collaterals Disadvantages Vascular region above bifurcations has disturbed nonlaminar flow and can present confusing picture mimicking intraluminal filling defects Ultrasonographic Findings Color Doppler Standard test to diagnose DVT Difficult visualization of iliac vessels 20% of iliac vein ultrasound studies are nondiagnostic in best vascular laboratories Left common femoral vein Doppler may show absence of respiratory variations suggesting proximal obstruction Collateral veins in groin or pubic area Angiographic Findings Venography (femoral, popliteal, or pedal access) Used as diagnostic and therapeutic tool Compression or occlusion of left common iliac vein Cross pelvic collaterals Dilated ascending lumbar vein with collaterals to vertebral plexus and hemiazygos veins Direct pressure measurement across iliofemoral stenosis during venography Significant stenosis: Difference > 2 mm Hg at rest or 3 mm Hg with exercise Nondiagnostic pressure gradient does not exclude diagnosis of IVCS Standard amount of dye injected into foot is not sufficient to evaluate iliac veins in pelvis Other Modality Findings Intravascular ultrasound (IVUS) 12.5 MHz or 20 MHz transducer introduced through sheath into lumen of veins Can determine vessel size and internal wall morphology May demonstrate intraluminal spur and assist with treatment planning (stent placement) Air plethysmography 1093

Diagnostic Imaging Cardiovascular Helps investigate and determine cause and severity of venous complaints and find evidence of proximal obstruction May also be nondiagnostic because of collateralization or insufficient narrowing to change flow dynamics Imaging Recommendations Best imaging tool Femoral venography IVUS MRV Protocol advice MRV: Include 2D time of flight to assess flow direction in left internal iliac vein and ascending lumbar vein DIFFERENTIAL DIAGNOSIS Immobilization Risk of developing DVT of lower extremities during conventional lower limb immobilization: 4.5-71.4% depending on indication for immobilization and method of diagnosing DVT Trauma Increased risk of developing DVT and pulmonary embolism following polytrauma Exact incidence is unknown Surgery Cancer-related surgery increases risk of DVT complications because of frequent venous trauma Postsurgery risk of developing DVT ranges from 15-40% (in most surgery patients) to as high as 60% in orthopedic surgery patients Radiation, Chemotherapy, and Hormonal Therapy Patients with malignancies have an increased risk of thromboembolism DVT and pulmonary embolism may present as complication after diagnosis of cancer Risk factors include radiotherapy, chemotherapy, and hormonal therapy Catheterization Presence of peripheral catheters increases risk of developing DVT in 2-40% P.13:32

Pelvic Tumors Patients with active cancer have 4× increased risk of developing venous thromboembolism compared with individuals without cancer Risk increases to 6.5× with chemotherapy Pelvic tumors or lymph nodes may compress left common iliac vein, thereby mimicking May-Thurner syndrome Chronic DVT Chronic DVT of iliac vein leads to small, narrowed occluded vein Underlying venous compression is difficult to assess in chronic DVT PATHOLOGY General Features Associated abnormalities DVT Physical entrapment of left CIV between right CIA and 5th lumbar vertebra Staging, Grading, & Classification 3 stages Asymptomatic compression at left iliocaval confluence without intrinsic changes or development of venous collateral vessels on venography Development of intraluminal filling defects (spurs) Iliofemoral thrombosis Gross Pathologic & Surgical Features Compression of left iliac veins against lumbar vertebrae can cause chronic irritation of vascular endothelium Leads to endothelial proliferation and hyperplasia Microscopic Features Collagen and elastin deposition result in formation of spurs Spurs: Replacement of normal intima and media of vein by well-organized connective tissue covered with endothelium Spurs create mechanical obstruction to flow and increase risk of left-sided iliofemoral thrombosis 1094

Diagnostic Imaging Cardiovascular CLINICAL ISSUES Presentation Most common signs/symptoms Unilateral swelling, pain, and aching of left leg Venous stasis and ulcers Other signs/symptoms Phlegmasia cerulea dolens Demographics Age 2nd-4th decades Gender M 2 mm Hg is suggestive of renal venous hypertension due to outflow obstruction May see enlarged, tortuous renal hilar varices draining into retroperitoneal venous collaterals DIFFERENTIAL DIAGNOSIS Arteriovenous Fistula Rapid flow hemodynamics and high venous pressures within enlarged renal vein May result in perirenal varices Congenital Venous Malformation May be extensive, with numerous points of communication with retroperitoneal veins Renal Vein Thrombosis Acute thrombosis results in renal dysfunction, back pain, and hematuria Frequently associated with systemic disease Dehydration Hypercoagulable state Neoplasm May be associated with intrinsic renal disease Nephrotic syndrome Glomerulonephritis Tumor Vascular Renal Tumor Arteriovenous shunting within tumor (e.g., renal cell carcinoma) may result in renal vein varices Spontaneous Splenorenal Shunt 1099

Diagnostic Imaging Cardiovascular Relatively infrequent condition occurring in and complicating hepatic cirrhosis and portal hypertension Elevated pressure within splenic vein causes spontaneous decompression into left renal vein Results in pressurized and dilated left renal vein Accompanying renal vein, retroperitoneal varices Obstructing Renal or Ureteral Calculus Obstructive uropathy from calculus causing unilateral flank, pelvic or abdominal pain, and hematuria Mimics symptoms of nutcracker syndrome Retroaortic Left Renal Vein (Vascular Variant) Compression of left renal vein as it courses behind aorta may cause left renal venous hypertension PATHOLOGY General Features Etiology Left renal vein normally courses between aorta & SMA Vein may be compressed between these structures; can result in left renal venous hypertension Venous hypertension leads to development of collaterals with intrarenal & perirenal varicosities Microscopic or gross hematuria can result from rupture of collateral veins into collecting system May be exacerbated in upright position Associated abnormalities Abdominal &/or left flank pain Hematuria Mild to moderate proteinuria P.13:36

Female pelvic varicosities/pelvic congestion syndrome Male varicoceles Pediatric chronic fatigue syndrome Important cause of nonglomerular hematuria to be considered in pediatric age group Left renal vein compression and resultant renal venous hypertension can lead to left gonadal vein congestion Gross Pathologic & Surgical Features Fibrosis may be present between aorta and SMA, where left renal vein courses Microscopic Features Renal biopsy shows spectrum from normal to mild or moderate mesangial proliferative nephritis CLINICAL ISSUES Presentation Most common signs/symptoms Flank, pelvic, or abdominal pain Often has accompanying hematuria, proteinuria Urine cytology, ureteroscopy, US, & renal biopsy are used in assessing unilateral hematuria etiology Other signs/symptoms If left ovarian vein reflux and pelvic varicosities occur, may have pelvic congestion syndrome symptoms If left-sided varicocele occurs in male patient, can cause testicular pain, infertility Clinical profile 2 age distributions; different presentations Thin young woman with recent substantial weight loss, new onset of vague flank pain, and hematuria Pediatric patient with microscopic hematuria and associated mild to moderate proteinuria that may be orthostatic, or with sudden onset of dark urine Demographics Age Pediatric and young adult Gender M=F Natural History & Prognosis Childhood nutcracker syndrome may be transient May spontaneously resolve with growth 1100

Diagnostic Imaging Cardiovascular May resolve as venous collaterals develop Extensive venous collateral development may result in female pelvic congestion syndrome or male varicocele Treatment Options, risks, complications Conservatively manage patients with mild symptoms Venous hypertension may resolve as collateral veins develop Persistent, recurrent, or massive hematuria is indication for treatment Surgical and endovascular treatment goal is to lower intrarenal venous pressure by eliminating venous outflow obstruction Various surgical treatment options in severe cases Autotransplantation of left kidney Left renal vein reanastomosis to IVC Nephrectomy Reported endovascular treatments have included angioplasty (PTA) and intravascular stent placement PTA is usually ineffective; stent typically required Some operators reluctant to place intravascular stent due to young age of patient & lack of data on long-term effectiveness/outcomes/complications Currently no consensus on indication for and success of endovascular treatment Gonadal vein embolization is used to decompress pelvic varices if pelvic congestion symptoms present in association with nutcracker syndrome DIAGNOSTIC CHECKLIST Consider Nutcracker syndrome in pediatric patient with hematuria and proteinuria Nutcracker syndrome in differential diagnosis of young female who presents with vague flank, pelvic, or abdominal pain, and hematuria Nutcracker syndrome as possible etiology/contributing factor to pelvic congestion syndrome symptoms in female patients or left-sided varicocele in males Image Interpretation Pearls Compression of left renal vein between aorta and SMA on US, CECT, or MRV is nondiagnostic for nutcracker syndrome in absence of intrarenal/perirenal varices Unless pressure gradient is demonstrated by Doppler measurements or direct venous manometry SELECTED REFERENCES 1. Wang X et al: Results of endovascular treatment for patients with nutcracker syndrome. J Vasc Surg. 56(1):142-8, 2012 2. Chen S et al: Endovascular stenting for treatment of Nutcracker syndrome: report of 61 cases with long-term followup. J Urol. 186(2):570-5, 2011 3. Fitoz S et al: Nutcracker syndrome in children: the role of upright position examination and superior mesenteric artery angle measurement in the diagnosis. J Ultrasound Med. 26(5):573-80, 2007 4. Scholbach T: From the nutcracker-phenomenon of the left renal vein to the midline congestion syndrome as a cause of migraine, headache, back and abdominal pain and functional disorders of pelvic organs. Med Hypotheses. 68(6):1318-27, 2007 5. Shin JI et al: Doppler ultrasonographic indices in diagnosing nutcracker syndrome in children. Pediatr Nephrol. 22(3):409-13, 2007 6. Zhang H et al: The left renal entrapment syndrome: diagnosis and treatment. Ann Vasc Surg. 21(2):198-203, 2007 7. Ahmed K et al: Current trends in the diagnosis and management of renal nutcracker syndrome: a review. Eur J Vasc Endovasc Surg. 31(4):410-6, 2006 8. Culafic D et al: Spontaneous splenorenal shunt in a patient with liver cirrhosis and hypertrophic caudal lobe. J Gastrointestin Liver Dis. 15(3):289-92, 2006 9. Rudloff U et al: Mesoaortic compression of the left renal vein (nutcracker syndrome): case reports and review of the literature. Ann Vasc Surg. 20(1):120-9, 2006 10. Chang CT et al: Nutcracker syndrome and left unilateral haematuria. Nephrol Dial Transplant. 20(2):460-1, 2005 11. Cuellar i Calabria H et al: Nutcracker or left renal vein compression phenomenon: multidetector computed tomography findings and clinical significance. Eur Radiol. 15(8):1745-51, 2005 12. Kim SJ et al: Long-term follow-up after endovascular stent placement for treatment of nutcracker syndrome. J Vasc Interv Radiol. 16(3):428-31, 2005 P.13:37

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(Left) Axial MRV in a patient with hematuria & pelvic pain shows marked compression of the left renal vein between the SMA and the anterior aspect of the abdominal aorta . Collateral perirenal varices are also present. Hematuria results when these varicosities rupture into a collecting system. (Right) More caudal axial MRV image shows the extensive retroperitoneal collaterals that have developed as a result of the nutcracker compression of the left renal vein and the associated left renal venous hypertension.

(Left) (A) DSA after MRV shows contrast attenuation where arterial structures compress the renal vein, with reflux into the gonadal vein and drainage into the IVC via a retroperitoneal collateral . (B) Left gonadal vein DSA shows pelvic varices . (Right) Gonadal vein coil embolization was performed to decompress the pelvic varices. (C) DSA shows coils distally, but filling of additional channels . (D) Coils were also placed proximally to preserve drainage via the retroperitoneal collateral .

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(Left) Nutcracker syndrome may be mimicked by pathology that causes left renal venous hypertension. Axial CECT shows extrinsic compression of the left renal vein against the aorta by a large mass in the left hepatic lobe. (Right) In addition to hepatic compression of the main left renal vein, there is a retroaortic left renal vein ,a vascular variant. Venous compression against the spine by the aorta further exacerbates left renal venous outflow obstruction. Perirenal varices are present.

Section 14 - Extracranial Cerebral Arteries Approach to Extracranial Cerebral Arteries > Table of Contents > Section 14 - Extracranial Cerebral Arteries > Approach to Extracranial Cerebral Arteries Approach to Extracranial Cerebral Arteries Bronwyn E. Hamilton, MD Introduction The most common indication for imaging of the extracranial arteries is stroke or transient ischemic attack. Atherosclerosis is the typical underlying pathology that results in narrowing of the cervical arteries, most commonly involving the proximal internal carotid artery (ICA) at the level of the carotid bulb; however, atherosclerosis may involve any of the extracranial cerebral arteries. Other typical locations of involvement are the great vessel origins from the aortic arch. The North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria remain the basis for establishing a clinically relevant carotid stenosis that may benefit from carotid endarterectomy (CEA). Patients may also be treated via an endovascular surgical approach with carotid artery stenting (CAS), possibly avoiding some of the associated surgical risks. Although atherosclerosis is the most common pathology of the extracranial vasculature, dissection is an important nonatherosclerotic disorder that puts patients at risk for ischemic stroke due to emboli &/or vascular occlusion. These are related most often to underlying connective tissue disorders and may account for up to 15% of ischemic strokes in young patients. Associations include bicuspid aortic valve, fibromuscular dysplasia, trauma, cystic medial necrosis, and amphetamine abuse. Diagnosis Conventional digital subtraction angiography (DSA) remains the gold standard against which other vascular imaging modalities are based; however, there is a continuing trend toward less invasive imaging modalities for establishing the presence of significant carotid artery stenosis. The most commonly used method of measuring ICA stenosis derives from NASCET criteria based on DSA. Ultrasound, computed tomographic angiography (CTA), and magnetic resonance angiography (MRA) have since replaced DSA as first-line imaging modalities in the work-up of patients suspected to be at risk of cervical vascular disease. Color duplex sonography of the carotid bifurcation is an effective means of detecting high-grade carotid artery stenosis or occlusion, but vascular calcifications, where present, may prevent accurate evaluation due to acoustic shadowing. The great vessel origins from the aortic arch, vertebral arteries, and portions of the carotid arteries are also not routinely demonstrated with ultrasound. Ultrasound is further limited by operator dependence and experience, which is less of a limiting factor with other imaging modalities. Lack of contrast and ionizing radiation are

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Diagnostic Imaging Cardiovascular advantages of sonographic screening that are particularly desirable in this era of safety awareness related to radiation and contrast effects. Two categories of severity of ICA stenosis are usually defined sonographically, based on blood flow velocities: (1) 5069% stenosis (the point at which flow velocity exceeds the normal because of atherosclerotic plaque) and (2) 70-99% stenosis, which represents more severe nonocclusive disease. CTA permits high spatial and contrast resolution, and it is probably the best noninvasive imaging modality with current multidetector capabilities. High-quality multiplanar reformats are routinely available, and the ability to visualize the vasculature in relation to the surrounding structures can be desirable in patients with anatomical variations. A recent cohort study of CTA obtained at the time of suspected stroke or ischemia identified carotid wall thickness > 4 mm as predictive of a future incident of ischemic stroke. The major limitation with CTA is the presence of calcified plaques that limit accurate vessel caliber measurement. Metallic implants or clips may cause severe streak artifacts that limit CTA. Very obese patients are suboptimally imaged as well. Stents in the carotid artery cause streak artifacts although assessment of vascular patency is often still achievable with wide window and level settings. Furthermore, CTA may not distinguish complete vascular occlusion from high-grade stenosis although it is generally much better than MRA in this regard. CTA has become an integral part of hyperacute stroke evaluation. An initial NECT scan, usually performed to rule out hemorrhage, is followed by a CTA ± CT perfusion study. The entire evaluation can be completed in < 30 minutes, including time-to-peak, cerebral blood flow, and cerebral perfusion calculations done using commercially available software. MRA can be performed without contrast and has no risks related to ionizing radiation and thus is a desirable screening modality; however, it remains expensive and limited by frequent artifacts. Advantages of MRA include a lower sensitivity to vascular calcifications and lack of ionizing radiation. MRA is very useful in excluding a hemodynamically significant vascular stenosis: A normal study has a very high specificity, and no further work-up is likely indicated. Abnormal MRA studies, however, suffer from a variety of artifacts that lower the predictive value of a positive study. When a hemodynamically significant stenosis is suggested on MRA, overestimation of low-flow states leads to diagnostic uncertainty that requires resolution by a secondary imaging modality. Some cases of apparent MRA occlusion are in fact proven to be patent vessels with ultrasound, CTA, or DSA, and may even be non-flow-limiting. Evaluation of the poststented carotid can also be limited by a signal drop-out from metallic susceptibility. Some patients are unable to undergo MRA because of extreme obesity or claustrophobia. Evaluation of dissection may benefit from including noncontrast fat-suppressed T1-weighted images through the neck in order to demonstrate crescentic mural subacute hematoma in patients suspected of having dissection as an etiology. Clinically significant stenoses identified by noninvasive techniques (ultrasound, CTA, MRA) may be best corroborated with a second noninvasive imaging modality or via conventional angiography prior to planned surgical or endovascular therapy. Any occurrence of suspected “critical” (> 99%) stenosis or pseudoocclusion should be confirmed with conventional angiography using delayed filming techniques to ensure visualization of a “string” sign that differentiates genuine occlusive disease from the potentially salvageable critical stenosis. Normal flow in the intracranial vessels on MR and circle of Willis MRA does not exclude extracranial disease. Most patients with atherosclerosis and ischemic symptoms should have both the intracranial and the extracranial circulations evaluated with either MRA or CTA. P.14:3

Imaging Recommendations The imaging recommendations presented in this section were recently outlined in an executive summary of the major medical societies involved in the diagnosis and treatment of stroke and vascular disease. Duplex Ultrasound Duplex ultrasonography performed by a qualified technologist in a certified laboratory is currently recommended (class I recommendation) as the initial diagnostic test to detect hemodynamically significant carotid stenosis in asymptomatic patients suspected of having carotid stenosis. Considering duplex sonography to detect carotid stenosis in asymptomatic patients with carotid bruit, in those with risk factors for carotid stenosis, and at annual reimaging of patients with documented stenosis > 50% (class II recommendation) is also reasonable. Patients with symptoms or signs of extracranial carotid artery disease (focal neurological deficit corresponding to territory supplied by either ICA) should undergo noninvasive vascular imaging with duplex sonography. MRA &/or CTA is recommended (class I recommendation) if sonographic evaluation is not possible or is equivocal. Duplex sonography, MRA, CTA, and DSA are considered class IIb recommendations for patients with nonspecific neurological symptoms if cerebral ischemia is a plausible cause. Indications for Carotid Revascularization Carotid revascularization either by CEA or CAS is recommended in symptomatic patients (class I recommendation); imaging should document a diameter luminal narrowing > 70% on noninvasive imaging (level of evidence: A) or > 50% by DSA (level of evidence: B). Prophylactic CAS can be considered in carefully selected patients with asymptomatic 1104

Diagnostic Imaging Cardiovascular carotid stenosis defined as a minimum of 60% luminal narrowing on DSA or 70% by duplex sonography (level of evidence: B). Restenosis following CEA or CAS can be established by any of the above imaging methods. Vertebral Artery Disease Noninvasive imaging by CTA or MRA is a class I recommendation for symptomatic patients with neurological symptoms referable to the posterior circulation or suspected subclavian steal syndrome. The same recommendation exists for asymptomatic patients having bilateral carotid occlusions or unilateral carotid occlusion with incomplete circle of Willis (level of evidence: C). Duplex sonography is not recommended given its limited ability to assess the posterior circulation. Patients may undergo serial noninvasive imaging (CTA or MRA) to assess disease progression. If noninvasive imaging fails to document vascular disease in patients for whom revascularization is a consideration, DSA is also considered useful (class IIa recommendations; level of evidence: C). Additional Limitations and Pitfalls MRA of the neck is especially challenging due to cardiac and respiratory motion or from reconstruction artifacts when a noncontrast 2D time-of-flight (TOF) technique is used. Two approaches are suggested to overcome poor visualization of the arch origins as well as motion and “venetian blind” artifacts: (1) Review source images for artifacts and (2) add a contrast-enhanced neck MRA as a “belt and suspenders” technique in case the 2D TOF fails. Venous contamination may occur with the contrast-enhanced neck MRA; however, reconstructing the source images into the axial plane can resolve questions due to overlap of venous and arterial structures on the coronal and sagittal MIP reconstructions. Typically obtained in the coronal plane, image acquisition is fast and not limited by slow flow in vessels. Note, however, that direction of flow, such as in subclavian steal syndrome, is not reliably determined with a contrast-enhanced MRA (or CTA) unless a time-resolved technique (such as 4D MRA) is utilized. The Future Current imaging research is focused on modalities that improve the identification of potentially vulnerable atherosclerotic plaque rather than simply measuring a caliber change. Ulcerative or irregular plaques having unstable characteristics that are at high risk of embolization are currently missed by standard NASCET criteria. High-resolution vessel wall imaging has advanced through dedicated coil design and higher field strength MR scanners. Additional benefits may be achieved through the use of black blood, conventional gadolinium-based enhanced vessel wall imaging, and currently off-label iron oxide nanoparticle contrast agents, which at some future time may offer better depiction of vulnerable plaque characterized by high macrophage content. This type of technology might permit a noninvasive means of determining the response to medical management or even the potential for targeted therapy. Selected References 1. Magge R et al: Clinical risk factors and CT imaging features of carotid atherosclerotic plaques as predictors of new incident carotid ischemic stroke: A retrospective cohort study. AJNR Am J Neuroradiol. 34(2):402-9, 2013 2. Brott TG et al: 2011 guideline on the management of patients with extracranial carotid and vertebral artery disease: executive summary. Vasc Med. 16(1):35-77, 2011. Erratum in: Vasc Med. 16(4):317, 2011 3. Metz S et al: Characterization of carotid artery plaques with USPIO-enhanced MRI: assessment of inflammation and vascularity as in vivo imaging biomarkers for plaque vulnerability. Int J Cardiovasc Imaging. 27(6):901-12, 2011 4. Brott TG et al: Stenting versus endarterectomy for treatment of carotid-artery stenosis. N Engl J Med. 363(1):11-23, 2010. Erratum in: N Engl J Med. 363(5):498, 2010. N Engl J Med. 363(2):198, 2010 5. Barnett HJ et al: Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med. 339(20):1415-25, 1998 6. Randomised trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC European Carotid Surgery Trial (ECST). Lancet. 351(9113):1379-87, 1998 7. Rothwell PM et al: A systematic review of the risks of stroke and death due to endarterectomy for symptomatic carotid stenosis. Stroke. 27(2):260-5, 1996 8. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis: North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med. 325(7):445-53, 1991 9. Disorders and Stroke Stroke and Trauma Division: North American Symptomatic Carotid Endarterectomy Trial (NASCET) investigators. Clinical alert: benefit of carotid endarterectomy for patients with high-grade stenosis of the internal carotid artery. National Institute of Neurological Stroke. 22(6):816-7, 1991 P.14:4

Image Gallery

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(Left) Graphic of the ICA bifurcation demonstrates fatty streaks (A), which are the earliest findings of atherosclerosis, and also shows unstable inflammatory plaque (thin-cap fibroatheroma) with rupture (B). Stenosis by NASCET is quantified by dividing (b-a) by b, where b = and a = . (Right) Sagittal reformat CTA in a symptomatic patient shows right ICA stenosis that does not meet the NASCET criteria for stenosis. The irregularity and ulceration suggest an unstable plaque, however.

(Left) Axial MRA shows absent signal in the left ICA . This could represent chronic occlusion or a low-flow state. (Right) AP MRA (same patient) shows occlusion of the left ICA at its origin . Only the left external carotid and vertebral arteries are patent. A flow gap with recovery of distal signal is noted in the right ICA . High-grade (> 90%) stenosis of the right ICA was confirmed at ultrasound, and carotid endarterectomy was subsequently successfully performed.

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(Left) Lateral DSA during early filming shows a tapered appearance suggesting occlusion of the ICA origin . (Right) Lateral DSA during late filming (same patient) again shows high-grade proximal ICA stenosis . Distal opacification of the cervical and intracranial ICA is now seen, compatible with high-grade stenosis, which is amenable to therapy. Late filming technique is important to detect the “string” sign at angiography. P.14:5

(Left) Coronal CTA shows a stenotic, irregular carotid bulb , calcified plaque at both the bulb and the proximal internal carotid artery , and normal filling of the distal cervical internal carotid artery . (Right) Sagittal CTA shows focal high-grade stenosis of the proximal internal carotid artery , typical of atherosclerotic narrowing without calcified plaque.

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(Left) Axial CTA in a trauma patient with bilateral ICA dissection demonstrates a focal outpouching in the right ICA , compatible with acute dissection. This is a common site of later pseudoaneurysm development. The lower density seen in the anterior aspect is typical of the false lumen whereas the linear hypodensity corresponds to the intimal flap . (Right) Axial CTA in the same patient shows similar findings in the left ICA with intimal flap and false lumen .

(Left) Coronal oblique CTA shows localized widening of the ICA that can be seen with dissection and pseudoaneurysm or variant atherosclerotic dolichoectasia (more typically seen in the vertebrobasilar system). Extreme dolichoectasia can result in low-flow states, causing ischemic infarction. (Right) AP MRA shows apparent occlusion of the proximal right ICA in a patient with acute stroke. A suspected occlusion should be confirmed with another modality to rule out high-grade ICA stenosis.

Acute Ischemic Stroke Key Facts Terminology Interrupted blood flow to brain resulting in cerebral ischemia/infarction with variable neurologic deficit Imaging Major artery (territorial) infarct Generally wedge-shaped; both GM & WM involved Embolic infarcts Often focal/small, at GM-WM interface NECT Hyperdense vessel (high specificity, low sensitivity) 1108

Diagnostic Imaging Cardiovascular “Dense MCA” sign: Acute thrombus in middle cerebral artery Loss of GM-WM distinction in 1st 3 hours (50-70%) “Insular ribbon” sign: Loss of GM-WM differentiation of insular cortex MR Best diagnostic clue is high signal on DWI with corresponding low signal on ADC ↓ CBF and ↓ CBV on perfusion MR (or CT) Top Differential Diagnoses Hyperdense vessel mimics Parenchymal hypodensity (nonvascular causes) Pathology Severely ischemic core CBF < (6-8 mL)/(100 g/min) Peripheral penumbra CBF = (10-20 mL)/(100 g/min) Clinical Issues 2nd most common cause of death worldwide Leading cause of morbidity in USA Treatment IV thrombolysis (< 3 hours of symptom onset) IA thrombolysis (selected acute strokes < 6 hours) Clinical diagnosis inaccurate in 15-20% of strokes

(Left) Coronal graphic illustrates a left M1 occlusion. A proximal occlusion affects the entire middle cerebral artery (MCA) territory, including the basal ganglia, which are perfused by lenticulostriate (perforating) arteries . Acute ischemia is often identified by subtle loss of the gray-white matter interfaces with blurring of the basal ganglia and an “insular ribbon” sign on the initial CT. (Right) Axial NECT demonstrates a hyperdense MCA sign representing acute thrombus in a patient with acute stroke symptoms.

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(Left) Axial NECT shows subtle loss of the right temporal gray-white matter interfaces representing an “insular ribbon” sign. (Right) Axial pCT (CBF) shows decreased blood flow in the right hemisphere related to hyperacute MCA ischemia. The CBF and CBV color maps cephalad to this slice showed a large MCA wedge-shaped defect. There was a similar perfusion abnormality on the TTP maps (not shown). Lack of a mismatch between CBV and TTP maps suggests that no ischemic penumbra is present. P.14:7

TERMINOLOGY Synonyms Stroke, brain attack, cerebrovascular accident Definitions Interrupted blood flow to brain resulting in cerebral ischemia/infarction with variable neurologic deficit IMAGING General Features Best diagnostic clue High signal on DWI with corresponding low signal on ADC Decreased cerebral blood flow (CBF) and cerebral blood volume (CBV) on CT or MR perfusion Location 1 or more vascular territories or at border zones (watershed) Size Dependent on degree of compromise and collateral circulation Morphology Territorial infarct Conforms to arterial territory Generally wedge-shaped Both gray matter (GM) and white matter (WM) are involved Embolic infarcts (often focal, at GM-WM interface) CT Findings NECT Hyperdense vessel (high specificity, low sensitivity) Represents acute thrombus in cerebral vessel(s) Hyperdense M1 segment of middle cerebral artery (MCA) in 35-50%; most common vessel involved “Dot” sign: Occluded MCA branches in sylvian fissure (16-17%) Loss of gray-white matter (GM-WM) distinction in 1st 3 hours (50-70%) Obscuration of deep gray nuclei Loss of cortical “ribbon” Parenchymal hypodensity If > 1/3 MCA territory initially hypodense, then larger lesion usually develops later Temporary transition to isodensity (up to 54%) at 2-3 weeks post ictus (CT “fogging”) 1110

Diagnostic Imaging Cardiovascular Gyral swelling, sulcal effacement 12-24 hours “Hemorrhagic transformation” in 15-45% Delayed onset (24-48 hours) most typical Can be gross (parenchymal) or petechial CECT Enhancing cortical vessels: Slow flow or collateralization acutely Absent vessels: Occlusion Perfusion CT (pCT): Assess ischemic core vs. penumbra; identify patients who benefit most from revascularization pCT calculates CBF, CBV, time to peak (TTP) Deconvolution can give mean transit time (MTT) Cortical/gyral enhancement after 48-72 hours CTA: Identify occlusions, dissections, stenoses, collaterals MR Findings T1WI Early cortical swelling and hypointensity, loss of GM-WM borders T2WI Cortical swelling, hyperintensity after 12-24 hours May normalize 2-3 weeks post ictus (MR “fogging”) FLAIR Parenchymal hyperintensity appears (6 hours post ictus) while other sequences normal Intraarterial FLAIR hyperintensity is early sign of major vessel occlusion or slow flow T2* GRE Detection of acute blood products Arterial “blooming” (thrombosed vessel) from clot susceptibility DWI Hyperintense restriction from cytotoxic edema Improves hyperacute stroke detection to 95% Best correlates with “ischemic core” (final infarct size); some diffusion abnormalities reverse May have reduced sensitivity in brainstem and medulla during 1st 24 hours Restriction typically lasts 7-10 days High signal can persist up to 2 months post ictus After 10 days, T2 effect may predominate over low ADC: T2 “shine-through” Corresponding low signal on ADC maps May normalize after tissue reperfusion Hyper- or isointensity on ADC map (T2 “shine-through”) may mimic diffusion restriction Distinguish cytotoxic from vasogenic edema in complicated cases May be helpful to evaluate new deficits after tumor resection PWI Dynamic contrast bolus or arterial spin-labeling techniques Maximum slope gives relative CBF and CBV Deconvolution gives absolute values Bolus-tracking T2* gadolinium PWI with CBV map ↓ perfusion; 75% larger than DWI abnormality DWI/PWI mismatch may identify penumbra (potentially viable but at-risk tissue) T1WI C+ Variable enhancement patterns evolve over time Hyperacute: Intravascular enhancement (stasis from slow antegrade or retrograde collateral flow) Acute: Meningeal enhancement (pial collateral flow appears in 24-48 hours, resolves over 3-4 days) Subacute: Parenchymal enhancement (appears after 24-48 hours, can persist for weeks/months) MRA: Major vessel occlusions, stenoses, status of collaterals MRS: Elevated lactate, decreased NAA Conventional MR sequences positive in 70-80% Restricted diffusion improves accuracy to 95% Diffusion tensor imaging (DTI)

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Diagnostic Imaging Cardiovascular Multidirectional diffusion-weighted images; at least 6 directions can be used to calculate DTI trace and generate ADC maps Higher spatial resolution May be more sensitive for small ischemic foci, emboli, cortical strokes P.14:8

Angiographic Findings Conventional: Vessel occlusion (cut off, tapered, “tram track”) Slow antegrade flow and slow retrograde collateral flow Intraluminal thrombus = filling defect Neurointerventional: Intraarterial (IA) fibrinolytic therapy for treatment of selected acute nonhemorrhagic stroke within 6-hour window IA mechanical clot removal with retriever device Imaging Recommendations Best imaging tool MR + DWI; T2* GRE Protocol advice NECT as initial study to exclude hemorrhage/mass CT perfusion and CTA if available MR using DWI/FLAIR/GRE ± MRA, PWI DSA with thrombolysis in selected patients DIFFERENTIAL DIAGNOSIS Hyperdense Vessel Mimics High hematocrit (polycythemia) Microcalcification in vessel wall Diffuse cerebral edema makes vessels appear relatively hyperdense Normal circulating blood always slightly hyperdense to normal brain Parenchymal Hypodensity (Nonvascular Causes) Infiltrating neoplasm (e.g., astrocytoma) Cerebral contusion Inflammation (cerebritis, encephalitis) Evolving encephalomalacia Dural venous thrombosis with parenchymal venous congestion and edema PATHOLOGY General Features Etiology Common causes Thrombotic vs. embolic, dissection, vasculitis, hypoperfusion Unusual causes Complicated vasculopathy, including posterior reversible encephalopathy syndrome and reversible cerebral vasoconstriction syndrome; venous stroke Early: Critical disturbance in CBF Severely ischemic core: CBF < (6-8 mL)/(100 g/min) Normal CBF ˜ (60 mL)/(100 g/min) Oxygen depletion, energy failure, terminal depolarization, ion homeostasis failure Bulk of final infarct → cytotoxic edema, cell death Later: Evolution from ischemia to infarction depends on many factors (e.g., hyperglycemia influences “destiny” of ischemic brain tissue) Ischemic penumbra: CBF = (10-20 mL)/(100 g/min) Theoretically salvageable tissue Target of thrombolysis, neuroprotective agents Associated abnormalities Cardiac disease, prothrombotic states Additional stroke risk factors: C-reactive protein, homocysteine Gross Pathologic & Surgical Features Acute thrombosis of major vessel Pale, swollen brain; GM-WM boundaries blurred Microscopic Features 1112

Diagnostic Imaging Cardiovascular After 4 hours: Eosinophilic neurons with pyknotic nuclei 15-24 hours: Neutrophils invade, and necrotic nuclei look like “eosinophilic ghosts” 2-3 days: Blood-derived phagocytes 1 week: Reactive astrocytosis, ↑ capillary density End result: Fluid-filled cavity lined by astrocytes CLINICAL ISSUES Presentation Most common signs/symptoms Focal acute neurologic deficit Paresis, aphasia, decreased mental status Demographics Age Usually older adults Epidemiology 2nd most common cause of death worldwide Among leading causes of morbidity in USA Natural History & Prognosis Clinical diagnosis inaccurate in 15-20% of strokes Malignant MCA infarct (coma, death) Up to 10% of all stroke patients Fatal brain swelling with increased ICP Treatment “Time is brain”: IV thrombolytic therapy window < 3 hours IA window < 6 hours except for vertebrobasilar thrombosis (up to 24 hours because of high morbidity and mortality) Patient selection most important factor in outcome Symptom onset < 6 hours No parenchymal hematoma on CT < 1/3 MCA territory hypodensity DIAGNOSTIC CHECKLIST Consider DWI positive for acute stroke only if ADC correlates Rarely, ischemia may mimic tumor or encephalitis SELECTED REFERENCES 1. Parrilla G et al: Hemorrhage/contrast staining areas after mechanical intra-arterial thrombectomy in acute ischemic stroke: imaging findings and clinical significance. AJNR Am J Neuroradiol. 33(9):1791-6, 2012 2. Kranz PG et al: Does diffusion-weighted imaging represent the ischemic core? An evidence-based systematic review. AJNR Am J Neuroradiol. 30(6):1206-12, 2009 3. Soares BP, Chien JD, Wintermark M. MR and CT monitoring of recanalization, reperfusion, and penumbra salvage: everything that recanalizes does not necessarily reperfuse! Stroke. 40(3 Suppl):S24-7, 2009 P.14:9

Image Gallery

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Diagnostic Imaging Cardiovascular

(Left) Axial DWI MR shows a large wedge-shaped hyperintensity related to restricted diffusion representing acute ischemia in a left MCA distribution. There is sparing of the basal ganglia, consistent with distal M1 occlusion. (Right) Axial NECT shows a hypodense wedge-shaped region of acute infarct with mild mass effect and sulcal effacement related to a right M1 embolic occlusion due to a calcified thrombus .

(Left) Axial NECT demonstrates bilateral posterior circulation hypodensities in a 20-month-old boy presenting with seizures after recent circumcision complicated by hematoma. (Right) Axial NECT shows hyperdense thrombus in the distal basilar artery of a 66-year-old woman with altered sensorium. Percutaneous thrombolysis is usually considered at later time points, up to 24 hours, because of the high morbidity and mortality associated with basilar thrombosis.

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(Left) Axial DWI MR shows hyperintensity related to restricted diffusion in a patient with vertebrobasilar disease and a posterior inferior cerebellar artery acute infarct. MR is superior to CT in evaluation of a posterior fossa stroke. (Right) Coronal CTA MIP reconstruction shows a focal filling defect within the proximal M1 segment in a patient with acute MCA ischemia. Intraarterial thrombolysis may be helpful if the patient presents to the emergency department within 6 hours of symptoms onset. P.14:10

(Left) Angiography in a 27-year-old man with a history of methamphetamine and tobacco use shows focal tight stenosis within the distal right M1 segment . He presented with stuttering symptoms of left-sided weakness and face droop. (Right) Sagittal T2WI MR shows multiple watershed ischemic foci in the deep white matter in a “string of pearls” configuration.

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(Left) Axial T2* GRE MR shows multifocal hemorrhages within an ischemic infarct in a 13-year-old boy with 3 weeks of fatigue, epistaxis, and acute loss of consciousness. He was found to have leukemia complicated by disseminated intravascular coagulation. (Right) Axial NECT shows cerebellar infarcts in a 34-year-old woman with bilateral vertebral artery dissections. Note effacement of basal cisterns and temporal horn dilation indicating upward transtentorial herniation.

(Left) Axial T2WI MR shows bilateral wedge-shaped occipital areas of hyperintensity in a 77-year-old woman, which do not allow for a reliable distinction between chronic and acute ischemia. (Right) Axial DWI MR in the same patient accurately reflects the acute area of left occipital ischemia , while encephalomalacia is apparent in the right occipital lobe . P.14:11

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(Left) Axial NECT shows multifocal hypodensities in the left cerebellum , consistent with embolic infarction within the left PICA distribution in this 40-year-old man with longstanding insulin-dependent diabetes and chronic renal failure. He presented with acute severe headache, nausea, and vomiting without localizing neurological finding. (Right) Axial CTA shows occlusion of the left vertebral artery . Compare with a normal dominant right vertebral artery .

(Left) Axial CTA shows intimal flap in a 47-year-old woman with bilateral internal carotid artery dissections. (Right) Axial NECT shows hyperdense left deep nuclei in a patient post recent IV thrombolytic therapy followed by mechanical thrombectomy for left MCA occlusion. These may reflect contrast staining &/or hemorrhage. Contrast gradually fades over time and does not imply worse prognosis. Matching hypointensity on GRE suggests hemorrhage.

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(Left) Axial T1 C+ MR shows heterogeneous gyriform enhancement in right MCA territory due to breakdown of BBB in subacute infarction. This appearance can mimic glioblastoma. Follow-up imaging may be important in patients without available imaging at the time of ictus to ensure appropriate evolution. (Right) Anteroposterior angiography shows left M1 occlusion and associated prominent lenticulostriate vessels .

Atherosclerosis, Extracranial Key Facts Terminology Degenerative process resulting from plasma lipid deposition in arterial walls Imaging Smooth/irregular narrowing of proximal ICA Ca++ in arterial walls Most common sites: ICA and vertebrobasilar arteries Protocol advice Color Doppler US as initial screening modality CTA/MRA or contrast MRA Consider DSA prior to carotid endarterectomy (CEA), in equivocal cases or if CTA/MRA shows “occlusion” Pathology NASCET method: % stenosis = [(normal lumen - minimal residual lumen)/normal lumen] × 100 Mild (< 50%), moderate (50-70%), severe (70-99%) Clinical Issues CEA if symptomatic carotid stenosis ≥ 70% (NASCET) Symptomatic moderate stenosis (50-69%) patients also benefit from CEA (NASCET) Asymptomatic patients benefit even with stenosis of 60% (ACAS) Carotid stenting depends on preop risk factors Signs/symptoms (can be asymptomatic) Carotid bruit, TIA, stroke (may be silent) Diagnostic Checklist DSA remains gold standard, but acceptable noninvasive preoperative imaging includes any 2 of US, CTA, time-of-flight, or contrast-enhanced MRA Late-phase DSA important to rule out pseudo-occlusion High-grade stenosis with “string” sign

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(Left) Graphic shows the mild form (A) of ASVD with fatty streaks and slight intimal thickening. The severe form (B) is characterized by intraplaque hemorrhage, ulceration, and platelet thrombi. NASCET calculation for % of stenosis = [(ba)/b] × 100 where b = normal ICA lumen and a = minimal residual ICA lumen. (Right) Coronal CTA oblique reconstruction shows a stenotic, irregular carotid bulb and calcified plaque at both the bulb and the proximal ICA with excellent filling of the distal cervical ICA .

(Left) Coronal oblique MRA shows a flow gap in the left internal carotid artery indicating severely restricted flow. The patient underwent an emergency left carotid endarterectomy. (Right) Axial T1WI C+ FS MR shows thickening of the internal carotid artery wall with only a small residual lumen . Atherosclerotic plaques often have neovascularity, which may cause intraplaque hemorrhage. P.14:13

TERMINOLOGY Abbreviations Atherosclerotic vascular disease (ASVD) Definitions Degenerative process resulting from plasma lipid deposition in arterial walls IMAGING General Features Best diagnostic clue Smooth or irregular narrowing of proximal internal carotid artery (ICA) Calcium deposition in arterial walls Location 1119

Diagnostic Imaging Cardiovascular Most common sites: ICA and vertebrobasilar arteries Aortic arch atheromas may cause ostial common carotid artery stenosis Affects large, medium, and small arteries & arterioles Size Ranges from microscopic lipid deposition to fatty streaks to gross plaque Generally 0.3-1.5 cm in diameter Fatty streaks may coalesce to form larger masses Morphology Begins initially as smooth, slight eccentric thickening of vessel intima Progresses to more focal and prominent eccentric thickening (subintimal macrocyte and smooth muscle cell deposition) Subintimal hemorrhage from “new vessels” further narrows lumen Ulceration with rupture of fibrous cap and intima occurs, resulting in “ulcerated plaque” CT Findings NECT Ca++ in vessel walls Large plaques may show low-density foci (soft plaque) Ectasia, tortuosity, fusiform vessel dilatation CECT Opacifies vessel lumen Can ↓ ability to visualize calcified plaque CTA Visualizes degree of stenosis vs. occlusion Can characterize plaque composition Shows hemorrhage, ulceration, fibrous cap Optimal coverage = 20 mm coverage on each side MIP and MPR reconstructions MPR: Better interobserver agreement Detection of ulceration: Up to 94% sensitivity, 99% specificity Best using axials and volume rendering MR Findings T1WI Wall thickening, luminal narrowing Absence of flow void May occur if vessel occluded or severely stenotic FLAIR Look for secondary signs of extracranial ASVD in brain (i.e., lacunes, infarcts) T1WI C+ FS High-resolution ICA imaging with dedicated surface coils can characterize plaque composition Hemorrhage/plaques with higher percentage of lipid-rich/necrotic core Independently associated with thin or ruptured fibrous cap (“at-risk” plaque) MRA 2D TOF or contrast enhanced Degree of stenosis visualized Signal loss may occur if high-grade (> 95%) stenosis Severe narrowing causes “flow gap” Ultrasonographic Findings Grayscale imaging allows visualization of noncalcified (hypoechoic) or calcified (hyperechoic) plaque in vessel wall Hypoechoic plaques are independent risk factor for stroke Doppler measures flow velocity; peak systolic velocity is best single velocity parameter for quantifying stenosis Spectral analysis allows evaluation of waveform; morphologic changes in waveform occur with increasing stenosis Color Doppler may detect high-grade occlusions more reliably than conventional Doppler Carotid intima media thickness (IMT) measurement can detect preclinical atherosclerotic disease and help stratify future risk Angiographic Findings Conventional angiography Identifies degree of stenosis, morphology of plaque, tandem stenoses, potential collateral pathways as coexisting pathology (i.e., aneurysm) Plaque surface irregularity associated with increased risk of stroke at all degrees of stenosis 1120

Diagnostic Imaging Cardiovascular Tandem lesions (distal stenoses) present in ˜ 2% of patients with significant cervical ICA lesions Hemodynamic effect of tandem stenoses is additive If only 1 tandem lesion is critical, flow is governed by more severe lesion Late-phase DSA important in high-grade stenosis or suspected occlusion to rule out pseudo-occlusion Imaging Recommendations Best imaging tool DSA for evaluating ICA stenosis; ≥ 4 projections recommended (AP, lateral, both obliques) DSA remains gold standard → acceptable noninvasive preoperative imaging includes any 2 of the following: US, CTA, TOF, or contrast MRA Protocol advice Color Doppler US as initial screening modality CTA/MRA or contrast MRA Consider DSA prior to carotid endarterectomy (CEA) in equivocal cases or if CTA/MRA shows “occlusion” DIFFERENTIAL DIAGNOSIS Dissection Typically spares carotid bulb; no calcification Seen in young or middle-aged groups Smoother, longer narrowing without intracranial involvement P.14:14

Fibromuscular Dysplasia “String of beads” > > long-segment stenosis Vasospasm Usually iatrogenic (catheter induced), transient PATHOLOGY General Features Etiology 3 main hypotheses Lipid hypothesis: Relates ASVD to high plasma low-density lipoprotein (LDL) levels causing LDLcholesterol deposits in arterial intima Response-to-injury hypothesis: ASVD is initiated by focal endothelial damage that initiates platelet aggregation and plaque formation Unifying theory: Suggests that endothelial injury is accompanied by increased permeability to macromolecules, such as LDL Other factors include diet, genes, mechanical stress (e.g., wall shear, anatomic variations), inflammation, hyperhomocysteinemia Complex, multifactorial process; pathogenesis remains controversial Probably no single cause, no single initiating event, and no exclusive pathogenetic mechanism Irregular plaques correlate with higher stroke risk Good collaterals correlate with lower stroke risk Significant ICA narrowing seen in 20-30% of ICA territory strokes vs. 5-10% of general population Genetics Probably multigenic Staging, Grading, & Classification Methods for calculating degree of stenosis vary: NASCET, ACAS, ECST, and VACSG NASCET method: % stenosis = [(normal lumen - minimal residual lumen)/normal lumen] × 100 Mild (< 50%), moderate (50-70%), severe (70-99%) Gross Pathologic & Surgical Features 2 well-accepted lesions described: Atheromatous plaque and fatty streak Atheromatous plaque: Most important, principal cause of arterial narrowing in adults Fatty streak: Precursor of atheromatous plaque; present universally in children, even in 1st year Intimal fatty streaks are earliest macroscopically visible lesions Plaques are whitish-yellow, protrude intraluminally, and vary in size Microscopic Features Fibroatheromatous plaques; develop after lipid deposition Plaques contain cells (monocytes/macrophages, leukocytes, smooth muscle), connective tissue, and intra/extracellular lipid deposits Necrotic core of lipid, cholesterol, cellular debris, lipid-laden foam cells, and fibrin form within plaque 1121

Diagnostic Imaging Cardiovascular Neovascularization may lead to vessel rupture, intraplaque hemorrhage, and ulceration Atheromatous plaque may rupture (fibrous cap may weaken and fracture); may lead to distal embolization CLINICAL ISSUES Presentation Most common signs/symptoms Variable: Asymptomatic, carotid bruit, TIA, stroke (may be silent) Clinical profile Stroke risk factors: Smoking, hypertension, diabetes, obesity, hypercholesterolemia, advanced age Demographics Age Usually middle-aged to elderly Gender M>F Ethnicity African Americans at highest risk for ASVD Epidemiology Leading cause of morbidity and mortality in USA Ischemic stroke → up to 40% of deaths in elderly Stroke occurs in > 70% of patients with ICA occlusion 90% of large, recent infarcts are caused by thromboemboli Epidemiological, experimental evidence that increased dietary lipid (cholesterol, saturated fat) and smoking correlate with atherosclerosis Treatment CEA if symptomatic carotid stenosis ≥ 70% (NASCET) Symptomatic moderate stenosis (50-69%) also benefits from CEA (NASCET) Asymptomatic patients benefit even with stenosis of 60% (ACAS) ICA stenting depends on preoperative risk factors DIAGNOSTIC CHECKLIST Consider To calculate degree of stenosis on DSA, ≥ 2 projections are required to profile plaque adequately For patients undergoing CEA, adequacy of collateral circulation is critical; consider MRA or DSA Pseudo-occlusion (very high grade stenosis) may be seen only on late-phase DSA CEA is still an option if ICA patent SELECTED REFERENCES 1. Arora S et al: Optimal carotid artery coverage for carotid plaque CT-imaging in predicting ischemic stroke. J Neuroradiol. 37(2):98-103, 2010 2. Babiarz LS et al: Contrast-enhanced MR angiography is not more accurate than unenhanced 2D time-of-flight MR angiography for determining > or = 70% internal carotid artery stenosis. AJNR Am J Neuroradiol. 30(4):761-8, 2009 3. Ota H et al: Hemorrhage and large lipid-rich necrotic cores are independently associated with thin or ruptured fibrous caps: an in vivo 3T MRI study. Arterioscler Thromb Vasc Biol. 29(10):1696-701, 2009 4. Chen CJ et al: Multi-Slice CT angiography in diagnosing total versus near occlusions of the internal carotid artery: comparison with catheter angiography. Stroke. 35(1):83-5, 2004 5. Nederkoorn PJ et al: Duplex ultrasound and magnetic resonance angiography compared with digital subtraction angiography in carotid artery stenosis: a systematic review. Stroke. 34(5):1324-32, 2003 P.14:15

Image Gallery

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(Left) Axial T2WI MR shows posterior encephalomalacia , likely a remote watershed ischemia. Note the loss of the right cavernous ICA flow void compared to the left . (Right) Axial MRA source image in the same patient shows a tiny but patent right ICA , illustrating the difficulty of differentiating a completely occluded ICA from a high-grade stenosis using conventional MR. Absent flow voids may reflect slow flow or occlusion and should be confirmed angiographically.

(Left) Lateral mid arterial phase DSA in the same patient shows filling of the right external carotid artery and branches. The cervical ICA is not seen but reconstitutes distally in the cavernous sinus by collaterals from the internal maxillary artery to the lateral mainstem trunk . (Right) Lateral angiography, late arterial phase, in the same patient shows a “string” sign: A trickle of contrast fills a small, irregular cervical ICA with antegrade flow. This patient may be a candidate for carotid endarterectomy.

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(Left) Lateral angiography in a patient with left hemisphere TIAs shows a high-grade stenosis distal to the left ICA bulb. Multiple irregularities in the atherosclerotic plaque are seen here as outpouchings of contrast . Irregularity is an independent risk factor for thromboembolic stroke, making this an “at risk” plaque. (Right) Lateral angiography in the same patient shows long-segment stenosis of the right ICA origin . Note the subtraction artifact from dense wall calcification .

Carotid Stenosis, Extracranial Key Facts Terminology Narrowing of cervical internal carotid artery or common carotid artery Imaging Extracranial carotid atherosclerotic vascular disease is most common at carotid bulb Carotid duplex US shows vessel narrowing with turbulent flow, increased peak systolic velocity, and spectral broadening CTA allows estimation of stenosis severity MRA flow gap can occur in stenoses > 95%, causing misdiagnosis of occlusion DSA is gold standard for evaluating severity of stenosis “String” sign = very high grade stenosis Slow antegrade “trickle” blood flow Top Differential Diagnoses Dissection Fibromuscular dysplasia Extrinsic compressive lesion (rare) Pathology Risk of stroke increases with stenosis severity, an indirect measure of plaque volume and potential for complicated plaque or embolization Clinical Issues NASCET showed that symptomatic patients with stenosis ≥ 70% (associated with stroke risk) benefit from carotid endarterectomy (CEA) ACAS showed that asymptomatic patients with 60% stenosis benefit from CEA SAPPHIRE compared CEA to carotid artery stenting (CAS) in high-risk patients with carotid stenosis Lower complication rate with CAS No difference in stroke after 3 years

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(Left) Sagittal reformat CTA shows irregularity and focal high-grade stenosis of the proximal internal carotid artery (ICA) , typical of atherosclerotic disease. Note areas of calcified plaque , which indicate an atherosclerotic etiology. (Right) Lateral DSA confirms similar findings to the CTA (same patient) typical of atherosclerotic high-grade carotid stenosis: Irregular short-segment narrowing with more proximal ulceration .

(Left) Sagittal MRA shows a flow gap in the ICA . MRA overestimates stenosis and occlusions; therefore, this must be confirmed with another vascular imaging modality to avoid misinterpretation. (Right) Color Doppler ultrasound (same patient) shows high flow velocities, anatomical narrowing, and spectral broadening, confirming that not an occlusion but a high-grade and hemodynamically significant stenosis (˜ 80-99%) of the ICA bifurcation is present. P.14:17

TERMINOLOGY Synonyms Carotid atherosclerotic vascular disease (ASVD) Definitions Narrowing of cervical segment of internal carotid artery (ICA) or common carotid artery (CCA) IMAGING General Features Best diagnostic clue Carotid duplex US shows vessel narrowing with turbulent flow, increased peak systolic velocity, and spectral broadening Location Extracranial carotid ASVD is most common at carotid bulb 1125

Diagnostic Imaging Cardiovascular Size Variable severity and length of stenosis; usually < 3 cm Smooth or irregular narrowing ± ulceration ± intraluminal thrombus CT Findings NECT Calcified ASVD plaque at CCA bifurcation ± ICA May show thromboembolic or hemodynamic cerebral infarction Typically ipsilateral anterior circulation Posterior cerebral artery (PCA) stroke possible via posterior communicating artery or fetal PCA CTA Useful as screening tool CTA allows estimation of stenosis severity Multiplanar reformatted images in sagittal and coronal planes are helpful Accuracy is reduced if extensive lesional calcification is present Maximal carotid wall thickness ≥ 4 mm is predictive of future carotid ischemic stroke Dental amalgam artifacts may hinder visualization May show intraluminal thrombus as filling defect within enhanced vessel Unreliable visualization of plaque ulceration Patchy/homogeneous low density in wall may be seen with large necrotic/lipid plaque MR Findings T1WI Reduced caliber of ICA flow void ± intraluminal signal due to thrombus or slow flow Fat-saturated sequence if dissection is suspected as alternate etiology Intramural crescentic high signal represents methemoglobin in vessel wall (dissection) DWI Most sensitive and specific for acute/subacute ischemia or infarction MRA Provides multidirectional imaging (vs. conventional DSA) Time-of-flight (TOF) MRA: Intravoxel dephasing causes signal loss with flow turbulence due to stenosis Affects 2D > 3D TOF images Accentuates severity of stenosis Gadolinium-enhanced MRA is superior to TOF sequences Flow gap can occur in stenoses > 95%, causing misdiagnosis of occlusion Brain T2WI, FLAIR, and DWI may show rosary-like lesions in centrum semiovale ipsilateral to stenosis, indicative of watershed ischemia or infarction Ultrasonographic Findings Grayscale ultrasound Calcified plaque causes acoustic shadowing and may limit assessment of vessel lumen Pulsed Doppler Duplex US: Flow velocity within stenosis is proportional to severity of stenosis Flow turbulence within and beyond stenosis Spectral broadening: Increased range of velocities is seen in moderate to severe stenoses Angiographic Findings Conventional DSA is gold standard for evaluation of carotid stenosis severity Use of reverse-curve catheters (e.g., Simmons) can avoid inadvertent crossing of carotid bifurcation stenosis with guidewire and dislodgement of plaque Intraluminal thrombus is seen as filling defect in contrast column Can evaluate collateral flow to ischemic hemisphere from communicating arteries and leptomeningeal collaterals by studying contralateral ICA and dominant vertebral artery “String” sign = very high grade stenosis, slow antegrade “trickle” blood flow Typically seen during late phase of angiogram May require prolonged DSA acquisitions for visualization Preocclusive state with high risk of stroke Important as carotid endarterectomy (CEA) or carotid artery stenting (CAS) may be an option if ICA is still patent More sensitive and specific than CTA and MRA for subtotal occlusion with string sign Other Modality Findings CT/MR perfusion 1126

Diagnostic Imaging Cardiovascular Can provide assessment of collateral flow to territory normally perfused by stenotic carotid artery Collateral circulation correlates with risk of hemodynamic ischemia or infarction Measurement of carotid stenosis severity North American Symptomatic Carotid Endarterectomy Trial (NASCET) method is most widely accepted NASCET: Denominator is normal poststenotic ICA diameter European Carotid Surgery Trial (ECST): Denominator is estimated normal diameter of carotid bulb Imaging Recommendations Ultrasound or CTA as screening tool CTA/MRA for comprehensive cerebrovascular evaluation DSA if US/CTA/MRA is equivocal or shows “occlusion” P.14:18

DIFFERENTIAL DIAGNOSIS Dissection Typically spares carotid bulb and ICA origin Usually no calcification (dystrophic Ca++ is rare) Intimal flap with differential filling of true and false lumens on DSA Crescentic intramural high signal (methemoglobin) on T1WI MR Fibromuscular Dysplasia Affects medium to large arteries M:F = 1:3 Age peak: 25-50 years Classically shows alternating segments of beading and stenoses involving extracranial ICA and external carotid, vertebral, and renal arteries Extrinsic Compressive Lesion (Rare) Carotid space neoplasm (e.g., carotid body paraganglioma, glomus jugulare tumor) PATHOLOGY General Features Etiology Risk of stroke increases with stenosis severity, an indirect measure of plaque volume and potential for complicated plaque/embolization Larger plaques are complicated by hemorrhage, necrosis, and disruption of fibrous cap and intima, causing embolization Plaque composition and surface morphology are also stroke risk factors Irregular plaque surface: ↑ stroke risk on medical treatment for all degrees of stenosis Hypoperfusion may cause watershed infarcts &/or centrum semiovale lesions Significant ICA narrowing is identified in 20-30% of carotid territory stroke patients (vs. 5-10% of general population) Gross Pathologic & Surgical Features Fatty streak: Raised lesion due to fatty deposit in intima Fibrous (fibrolipid) plaque: Cholesterol + fibrous tissue with collagen cap Complicated plaque: Unstable; may rupture, thrombose, calcify, or hemorrhage Microscopic Features ASVD: Fatty streaks, lipid-laden macrophages and smooth muscle cells, fibrous cap, cholesterol deposits, foam cells, plaque rupture ± thrombus CLINICAL ISSUES Presentation Stroke is 3rd most common cause of death in Western countries Transient ischemic attack (TIA): Neurological deficit that spontaneously resolves in < 24 hours 80% resolve in < 1 hour Precedes 30% of strokes 50% of subsequent strokes occur < 1 year from TIA Reversible ischemic neurological deficit: Neurological deficit > 24 hours but < 3 weeks Amaurosis fugax (transient, monocular embolic blindness) Asymptomatic carotid bruit: 20% have > 60% ICA stenosis (3× normal population) Natural History & Prognosis Progressive Treatment 1127

Diagnostic Imaging Cardiovascular Reduction of risk factors, which include hypertension, smoking, diabetic control, and hypercholesterolemia Medical: Aspirin, statins NASCET (1991) Symptomatic stenosis ≥ 70% (associated with significant stroke risk) benefits from CEA Symptomatic moderate stenosis (50-69%) also benefits from endarterectomy in selected cases Asymptomatic Carotid Atherosclerosis Study (ACAS, 1995) Asymptomatic patients with 60% stenosis benefit from CEA CAS is becoming increasingly utilized and substantiated as viable alternative to CEA CAS with distal protection device is associated with risk of periprocedural stroke ≤ CEA Stenting and Angioplasty With Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) 2004 study Compared CEA with CAS in high-risk patients (comorbidities, age > 80 years, recent surgery, etc.) with symptomatic and asymptomatic carotid stenoses Lower complication rate with CAS; no difference in stroke incidence after 3 years (7.1% CAS vs. 6.7% CEA) DIAGNOSTIC CHECKLIST Consider Use of reverse-curve catheters for catheterization of CCA when carotid stenosis is suspected Image Interpretation Pearls MRA often exaggerates degree of stenosis Look for intraluminal filling defect (CAS is contraindicated if intraluminal thrombus is present) SELECTED REFERENCES 1. Magge R et al: Clinical risk factors and CT imaging features of carotid atherosclerotic plaques as predictors of new incident carotid ischemic stroke: a retrospective cohort study. AJNR Am J Neuroradiol. 34(2):402-9, 2013 2. Brott TG et al: 2011 ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/SAIP/SCAI/SIR/SNIS/SVM/SVS guideline on the management of patients with extracranial carotid and vertebral artery disease: executive summary: Stroke. 42(8):e420-63, 2011. Erratum in: Stroke. 42(8):e541, 2011 3. Halliday A et al: Prevention of disabling and fatal strokes by successful carotid endarterectomy in patients without recent neurological symptoms: randomised controlled trial. Lancet. 363(9420):1491-502, 2004 4. Yadav JS: Carotid stenting in high-risk patients: design and rationale of the SAPPHIRE trial. Cleve Clin J Med. 71 Suppl 1:S45-6, 2004 P.14:19

Image Gallery

(Left) Sagittal reformat CTA demonstrates a high-grade stenosis of the internal carotid artery distal to its origin and irregular narrowing and ulceration more proximally at the carotid bifurcation , findings typical for atherosclerotic narrowing. (Right) Lateral DSA (same patient) demonstrates similar findings compared with CTA: Ulceration and narrowing at the internal carotid artery origin and more distal high-grade stenosis .

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(Left) Sagittal CTA shows irregular ulcerated plaque at the internal carotid artery origin, typical of atherosclerotic disease. Although a hemodynamically significant stenosis may not be present, this plaque is morphology prone to embolic complications. (Right) Oblique 3D reformation of a CTA shows diffuse beading of the distal cervical internal carotid artery , typical in appearance for fibromuscular dysplasia. Both internal carotid and renal arteries (not shown) were similarly affected.

(Left) Coronal MRA appears nearly normal in this patient with distal cervical left ICA dissection. Note the mild smoothly marginated caliber change that is easily missed until compared with the contralateral side. The ICAs, unlike the vertebral arteries, normally demonstrate a symmetric size in the neck. (Right) Axial T1WI FS MR can be useful to confirm suspected dissection, as in this case (same patient) where crescentic mural hematoma is visible around the luminal flow void.

Carotid Dissection Key Facts Terminology Internal carotid artery dissection (ICAD): Delamination of ICA wall by tear or rupture of intima allowing blood to gain access to subintima and media Imaging Pathognomonic findings of dissection: Intimal flap or double lumen (seen in < 10% of cases) Aneurysmal dilatation seen in 30% of cases Commonly in distal cervical segment of ICA Focal pseudoaneurysm unusual Flame-shaped ICA occlusion (acute phase) 1129

Diagnostic Imaging Cardiovascular ICAD most commonly originates in ICA 2-3 cm distal to carotid bulb and variably involves distal ICA Stops before petrous ICA MR T1 with fat suppression best sequence for hyperintense mural hematomas Top Differential Diagnoses Fibromuscular dysplasia Carotid artery fenestration Atheromatous plaque Traumatic ICA pseudoaneurysm Glomus vagale paraganglioma Carotid space schwannoma Clinical Issues Ipsilateral pain in face, jaw, head or neck Oculosympathetic palsy (miosis and ptosis, partial Horner syndrome) Ischemic symptoms (cerebral or retinal TIA or stroke) Bruit (40%) Lower cranial nerve palsies (especially CN10) Pulsatile tinnitus 20% of ICADs are bilateral or involve vertebral arteries

(Left) Lateral graphic depicts typical ICA dissection. Note that the dissection begins above the bifurcation and ends at the skull base . Cross section of a subintimal hematoma is also shown. (Right) Iatrogenic carotid artery dissection occurred during interventional procedure but was asymptomatic and subsequently resolved. On oblique DSA, the intimal flap is seen as curvilinear intraluminal filling defect extending from the proximal ICA to the carotid canal.

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Diagnostic Imaging Cardiovascular (Left) Oblique MIP image of MRA study from the same patient demonstrates a long-segment ICA dissection extending to the skull base . Axial source images of MRA must be reviewed in their entirety to correlate with MIP images. En face depiction of flap on MIP will obscure this finding. (Right) Axial T1WI FS MR of the same patient shows intimal flap without mural hematoma as isointense band dividing true and false lumens of ICA. Note that the overall lumen caliber is considerably larger than the normal right ICA . P.14:21

TERMINOLOGY Abbreviations Carotid artery dissection (CAD), internal carotid artery dissection (ICAD) Definitions ICAD: Delamination of ICA wall by tear or rupture of intima allowing blood to gain access to subintima and media IMAGING General Features Best diagnostic clue Pathognomonic findings of dissection: Intimal flap or double lumen (seen in < 10%) Wall (mural) hematoma, most often with narrowing of lumen, visualized on cross-sectional imaging Flame-shaped ICA occlusion (acute phase) Aneurysmal dilatation seen in 30%, commonly in cervical segment of ICA proximal to carotid canal Location CADs most commonly originate in ICA 2-3 cm distal to carotid bulb and variably involve distal ICA Size ICAD extends over variable length along distal ICA ICAD almost always stops before petrous ICA Morphology ICA luminal narrowing ± focal aneurysmal dilatation CT Findings CECT Shows narrowing of dissected artery by mural hematoma ± aneurysmal dilatation May show dissection flap ± double lumen CTA Shows narrowing of ICA lumen ± aneurysmal dilatation May show intramural thrombus as low-attenuation crescent May show dissection flap ± double lumen MR Findings T1WI T1 MR with fat saturation: Intramural hematoma (hyperintense crescent adjacent to ICA lumen) Aneurysmal ICAD: Laminated stages of thrombosis (with intervening layers of methemoglobin and hemosiderin) T2WI Mural hematoma may have variable signal intensity depending on acuity Aneurysmal form: Laminated stages of thrombosis (with intervening layers of methemoglobin and hemosiderin) FLAIR Brain: Intracranial sequela of ischemia/stroke in ICA distribution if scanned after 6 hours of onset T2* GRE Hemorrhagic products in vessel wall/aneurysm may cause blooming susceptibility artifact DWI Brain: Intracranial acute sequelae of ischemia/stroke show restricted diffusion MRA Vessel tapering ± aneurysmal dilatation of dissected ICA Ultrasonographic Findings Abnormal pattern of flow identified in > 90% of cases Intimal flap or intramural hematoma seen in < 33% of cases Dissection site usually not seen Angiographic Findings Pathognomonic: Intimal flap or double lumen (true & false) ICA lumen stenosis with slow flow 1131

Diagnostic Imaging Cardiovascular Dissecting aneurysm or pseudoaneurysm Flame-shaped, tapered occlusion is usually acute Fibromuscular dysplasia changes in 15% of patients Spares carotid bulb; classically ends at proximal carotid canal Imaging Recommendations Best imaging tool Angiography may be gold standard for CAD, but few cases undergo angiography CTA and MRA emerge as superior technologies to image intramural and extraluminal dissection components Frequently, 1st step in imaging evaluation Protocol advice Best sequence for hyperintense mural hematomas: MR T1 with fat suppression DIFFERENTIAL DIAGNOSIS Carotid Fibromuscular Dysplasia Clinical: Young female with TIA Imaging: “String of beads” and long-segment stenosis May have associated CAD Carotid Artery Fenestration Clinical: Asymptomatic, normal variant Imaging: Short segment fenestration often at C1-C2 level Atheromatous Plaque Clinical: Frequently, history of hypertension Imaging: MRA/CTA may show irregular excavation of vessel, narrowing of vessel due to fibrofatty plaque ± calcified plaque in vessel wall Traumatic ICA Pseudoaneurysm Clinical: History of recent or remote trauma Imaging: Dissecting aneurysm may be indistinguishable from traumatic pseudoaneurysm Glomus Vagale Paraganglioma Clinical: Slowly growing painless mass Imaging: Nasopharyngeal carotid space mass with “salt and pepper” flow phenomena on MR and avid enhancement on CECT and T1 C+ MR Carotid Space Schwannoma Clinical: Slowly enlarging painless mass; neurological symptoms often absent Imaging: Carotid space mass without obvious flow voids on T1; hyperintense on T2 P.14:22

PATHOLOGY General Features Etiology Dissections usually arise from intimal injury causing blood to enter arterial wall and intramural hematoma to form 2 types of associated aneurysm Dissecting aneurysm: ≥ 1 normal arterial wall layers present in wall of this aneurysm Pseudoaneurysm: Subadventitial dissection causes pseudoaneurysm Arterial wall contains no normal layers, just organized clot 3 types of CAD Spontaneous dissection: Most common; etiology unknown Post-traumatic: Vertebral artery dissection > CAD Predisposed: Dissection from arteriopathy (fibromuscular dysplasia, genetic syndromes) Associated abnormalities Fibromuscular dysplasia Ehlers-Danlos type 4 Marfan syndrome Osteogenesis imperfecta type 1 Autosomal dominant kidney disease ICA most common cervical artery to dissect Extracranial ICA more likely to dissect than intracranial ICA Pharyngeal portion of extracranial ICA is mobile (carotid bulb to skull base) and can enlarge 1132

Diagnostic Imaging Cardiovascular Staging, Grading, & Classification Biffl grading scale Grade I: Intimal irregularity with < 25% narrowing Grade II: Dissection with > 25% narrowing Grade III: Arterial pseudoaneurysm Grade IV: Arterial occlusion Grade V: Transection with extravasation CLINICAL ISSUES Presentation Most common signs/symptoms Ipsilateral pain in face, jaw, head, or neck Oculosympathetic palsy (miosis and ptosis, partial Horner syndrome) Ischemic symptoms (cerebral or retinal TIA or stroke) Bruit (40%) Other signs/symptoms Lower cranial nerve palsies (especially CN10) Pulsatile tinnitus Hyperextension or neck rotation (yoga, exercise, vomiting, sneezing, resuscitation, neck manipulation) Congenital Horner syndrome with traumatic delivery Clinical profile Head and neck pain, partial Horner syndrome, TIA/stroke triad (˜ 33%) Demographics Age Age range: 30-55 years Average age: 40 years Epidemiology Annual incidence: 2.5-3 per 100,000 Extracranial CAD > > intracranial CAD or common carotid artery dissection 20% of ICADs are bilateral or involve vertebral arteries Natural History & Prognosis 90% of stenoses resolve 66% of occlusions are recanalized 33% of aneurysms decrease in size Risk of recurrent dissection = 2% (1st month), then 1% per year (usually in another vessel) ↑ risk of stroke due to thromboembolic disease; related to severity of initial ischemic insult, not to degree of stenosis Death from CAD < 5% Treatment Intravenous heparin + oral warfarin (Coumadin) (unless contraindicated by hemorrhagic stroke) Antiplatelet therapy in asymptomatic patients if stable imaging findings for 6 months Endovascular stent placement uncommonly used Surgical treatment is rare option Used in patients whose symptoms are refractory to medical and endovascular therapies Interposition graft Relatively high morbidity and mortality DIAGNOSTIC CHECKLIST Image Interpretation Pearls ICAD may present as luminal occlusion, stenosis, or aneurysmal dilatation (pseudoaneurysm) SELECTED REFERENCES 1. Rao AS et al: Long-term outcomes of internal carotid artery dissection. J Vasc Surg. 54(2):370-4; discussion 375, 2011 2. Faivre A et al: Internal carotid artery dissection occurring during intensive practice with Wii video sports games. Neurology. 73(15):1242-3, 2009 3. Georgiadis D et al: Aspirin vs anticoagulation in carotid artery dissection: a study of 298 patients. Neurology. 72(21):1810-5, 2009 4. Ansari SA et al: Endovascular treatment of distal cervical and intracranial dissections with the neuroform stent. Neurosurgery. 62(3):636-46; discussion 636-46, 2008 5. Chandra A et al: Spontaneous dissection of the carotid and vertebral arteries: the 10-year UCSD experience. Ann Vasc Surg. 21(2):178-85, 2007 1133

Diagnostic Imaging Cardiovascular 6. McIntosh A et al: Carotid artery dissection and middle cerebral artery stroke following methamphetamine use. Neurology. 67(12):2259-60, 2006 7. Wu HC et al: Spontaneous bilateral internal carotid artery dissection with acute stroke in young patients. Eur Neurol. 56(4):230-4, 2006 8. Biondi A et al: Progressive symptomatic carotid dissection treated with multiple stents. Stroke. 36(9):e80-2, 2005 9. Edgell RC et al: Endovascular management of spontaneous carotid artery dissection. J Vasc Surg. 42(5):854-60; discussion 860, 2005 10. Khan AM et al: Chiropractic sympathectomy: carotid artery dissection with oculosympathetic palsy after chiropractic manipulation of the neck. Mt Sinai J Med. 72(3):207-10, 2005 11. Knibb J et al: Internal carotid artery dissection presenting with ipsilateral tenth and twelfth nerve palsies and apparent mass lesion on MRI. Br J Radiol. 78(931):659-61, 2005 12. Benninger DH et al: Mechanism of ischemic infarct in spontaneous carotid dissection. Stroke. 35(2):482-5, 2004 P.14:23

Image Gallery

(Left) Lateral film from conventional common carotid artery angiogram in a patient with traumatic injuries from motor vehicle crash shows right ICA dissection. ICA smoothly tapers to occlusion just above the bifurcation . (Right) Transverse T1WI FS MR of right ICA dissection shows high signal intensity in a subacute mural hematoma of the right ICA near the skull base with low signal in the residual narrowed lumen. Note that the cross-sectional diameter of ICA has increased compared to that of the normal left ICA .

(Left) Axial T1WI MR in a 47-year-old man who fell skiing 3 weeks prior to developing left frontotemporal headache shows T1 shortening within the crescentic subacute clot in the false lumen of the dissected left ICA. Note the high signal thrombus within the true lumen of the vessel, which was occluded. (Right) Axial T2WI FS MR, a more 1134

Diagnostic Imaging Cardiovascular superior image in the same patient, shows high signal in the petrous right ICA from thrombosis due to proximal dissection and occlusion .

(Left) Lateral angiography in a 49-year-old patient in high-speed MVA shows wall irregularity in the left ICA and intimal flap resulting from carotid dissection . Dissection has resulted in a focal high-grade stenosis . (Right) Coronal CTA curved reconstruction in the same patient performed 2 years after injury demonstrates persistent vessel abnormality of prior dissection with residual wall irregularity and distal aneurysmal dilatation . The intimal flap is no longer visible.

Carotid Pseudoaneurysm, Extracranial Key Facts Terminology Paravascular cavitated thrombus in continuity with carotid artery Not contained by true vessel wall (tunica intima and media), hence “pseudo” or “false” aneurysm Imaging Round/ovoid/lobulated iso- to slightly hyperdense carotid space (CS) mass ± local bony expansion or remodeling if above skull base CTA useful as first-line imaging tool for both extra- and intracranial carotid injury Classic imaging appearance: CS mass that communicates directly with carotid artery Top Differential Diagnoses Dissecting aneurysm Arteriovenous fistula Fibromuscular dysplasia True carotid artery aneurysm Pathology May result from dissection from any etiology (trauma, iatrogenic, fibromuscular dysplasia, etc.) In absence of embolic complications, may be more benign than previously assumed Up to 25% may resolve, ˜ 15% decrease in size, and ˜ 60% do not change without therapy Clinical Issues Can be occult, asymptomatic (2.5% of patients with blunt injury) Diagnostic Checklist True cervical carotid aneurysms are rare Look for associated trauma/dissection Multiplanar CTA reformats is usually diagnostic Look for associated stenosis, contained thrombus

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(Left) A 41-year-old patient was in a car accident 4 weeks earlier, presenting with a small right middle cerebral artery (MCA) infarction at the time of initial trauma. Axial CTA of the neck shows tapering occlusion of the right internal carotid artery (ICA) and relatively normal lumen of the left ICA near the skull base . (Right) Axial T1WI FS MR obtained with presaturation pulses at inferior and superior margin of slab shows hyperintense crescentic mural hematoma on the right . ICA was occluded just superior to the depicted section.

(Left) Axial CTA of the same patient with ICA occlusion secondary to dissection and contralateral pseudoaneurysm shows that the left ICA lumen is irregularly dilated near the carotid canal , representing ICA pseudoaneurysm. (Right) Oblique MRA (same patient) demonstrates tapering occlusion of the right ICA just above the bifurcation . The left ICA is remarkable for ICA pseudoaneurysm at the skull base, just proximal to the carotid canal . The pseudoaneurysm was subsequently embolized. P.14:25

TERMINOLOGY Synonyms “False” carotid aneurysm Definitions Paravascular cavitated thrombus in continuity with carotid artery lumen Not contained by true vessel wall (tunica intima and media), hence “pseudo” or “false” aneurysm IMAGING General Features Best diagnostic clue Carotid space (CS) mass commonly at skull base with luminal dilatation and concentric mural hematoma 1136

Diagnostic Imaging Cardiovascular Perivascular cavity communicates with true lumen of native carotid artery Location Common carotid artery (CCA) and cervical segment of internal carotid artery (ICA) > petrous > cavernous > intradural ICA Morphology May be fusiform dilatation vs. saccular outpouching Classic imaging appearance: CS mass that communicates directly with carotid artery CT Findings NECT Round/ovoid/lobulated iso- to slightly hyperdense CS mass ± local bony expansion or remodeling if above skull base May contain mural thrombus of varying ages CECT Irregular widening of vessel contour Outpouching of lumen from carotid artery with discernible neck May compress carotid artery true lumen Enhances to same degree as opacified lumen of other vascular structures CTA Multiplanar reformats ± 3D reconstructions provide excellent visualization of pseudoaneurysm size + orientation of connection with carotid artery lumen ± contained thrombus MR Findings T1WI Heterogeneous signal (usually isointense ± flow void, phase artifact) T2WI Heterogeneous signal (mixed hypo/hyperintense ± flow void) FLAIR Useful for detection of end-organ (brain) injury due to thromboemboli from pseudoaneurysm sac or hemodynamic compromise from compression of true lumen T2* GRE Significant blooming artifact from mural hematoma DWI Most sensitive for acute ischemia or infarction from thromboemboli or hypoperfusion MRA Visualization depends on flow dynamics within and adjacent to pseudoaneurysm Turbulent flow may result in signal loss and reduce conspicuity Gadolinium-enhanced MRA may provide superior depiction of lumen and aneurysm Ultrasonographic Findings Color Doppler Duplex ultrasound is useful as screening tool Turbulent flow, pseudoaneurysm ± compression (stenosis) of carotid artery Angiographic Findings Conventional DSA remains gold standard for detection and characterization of carotid artery injury; useful for treatment planning: Surgical vs. endovascular vs. conservative/medical Arch aortogram, arteriogram of carotid bifurcation should be performed prior to more distal selective catheterization of injured carotid artery Imaging of contralateral carotid ± vertebral artery/arteries should be considered if concurrent injury is suspected in case of multitrauma; necessary if carotid sacrifice is being considered as therapeutic option Demonstration of aneurysm morphology, aneurysm neck, size ± compression/stenosis of carotid artery lumen Imaging Recommendations Best imaging tool CTA useful as first-line imaging tool for both extra- and intracranial carotid injuries Duplex sonography useful as rapid screening examination in acute setting of suspected cervical vascular injury DIFFERENTIAL DIAGNOSIS Dissecting Aneurysm Intramural hematoma from rupture of vasa vasorum or intimal tear dilates and weakens vessel wall May see intimal flap between true and false lumens 1137

Diagnostic Imaging Cardiovascular Arteriovenous Fistula May occur as rare complication of carotid pseudoaneurysm rupture → arteriovenous shunt to neck veins or cavernous sinus More commonly associated with penetrating neck injury Fibromuscular Dysplasia Irregular outpouchings from vessel lumen, usually along upper cervical ICA segment, bilateral in 60% Occurs in carotid circulation > vertebral arteries Renal artery involvement most common Often asymptomatic finding M:F = 1:3 Classic = “string of beads” with alternating segments of dilatation and strictures Less symmetric forms also occur True Carotid Artery Aneurysm Contained by all layers of vessel wall as opposed to pseudoaneurysm P.14:26

CCA and cervical ICA locations are extremely rare True cavernous ICA aneurysms are associated with fibromuscular dysplasia and Ehlers-Danlos syndrome Supraclinoid ICA blister and berry aneurysms may cause subarachnoid hemorrhage PATHOLOGY General Features Etiology May result from dissection from any etiology (trauma, iatrogenic, fibromuscular dysplasia, etc.) Represents contained vessel rupture in soft tissues Carotid dissection may result in characteristic pseudoaneurysm at skull base In absence of embolic complications, may be more benign than previously assumed Up to 25% may resolve, ˜ 15% decrease in size, and ˜ 60% do not change without therapy Rarely occurs as sequela of deep neck space infection with necrosis of vessel wall (mycotic pseudoaneurysm) Carotid blowout syndrome Carotid pseudoaneurysm ± active bleeding into neck soft tissues or oral cavity Related to aggressive primary and salvage surgery for head and neck cancer, irradiation Requires emergent endovascular vessel occlusion or placement of covered stent Associated abnormalities Injury to other vessels possible due to traumatic etiology; should be sought on CTA/DSA > 80% of all cervical vascular injuries involve carotid arteries Vessel wall disruption results in periluminal hemorrhage with contained extravasation Paravascular thrombus forms, cavitates, communicates with parent vessel Gross Pathologic & Surgical Features Bluish-purple paravascular CS mass contained by fascia, organized hematoma ± adventitia Microscopic Features Wall of pseudoaneurysm does not contain intima, internal elastic lamina, muscularis layers; adventitia may be present CLINICAL ISSUES Presentation Can be occult, asymptomatic (2.5% of patients with blunt injury) 50-60% have palpable cervical mass (± pulsation) 40% neurologic symptoms Horner syndrome CN9-CN11 palsy Jaw pain Cerebral ischemia/infarction Cavernous ICA pseudoaneurysm rupture may cause Massive epistaxis (rupture into sphenoid sinus) May be life threatening Direct carotid cavernous fistula (rupture into cavernous sinus) → ophthalmoplegia, proptosis, chemosis Demographics 1138

Diagnostic Imaging Cardiovascular Epidemiology 1/3 of cervical ICA vascular injuries caused by penetrating trauma Natural History & Prognosis Variable; may enlarge, resolve spontaneously, undergo thrombosis, rupture 45% combined stroke/mortality rate after ligation of parent vessel 23% stroke/mortality with observation only < 5% major morbidity/mortality if parent vessel is repaired or reconstructed endovascularly Treatment Goal is occlusion of pseudoaneurysm with preservation of ICA (constructive) Alternative is therapeutic carotid sacrifice (occlusion) after ICA balloon test occlusion (destructive) Stent-supported coil embolization of pseudoaneurysm sac or placement of covered stent to exclude sac is usually curative Placement of noncovered stent may change hemodynamics within sac sufficiently to promote thrombosis without need for additional embolization with coils DIAGNOSTIC CHECKLIST Consider History of trauma, surgery ± radiation therapy for head and neck cancer Image Interpretation Pearls True cervical carotid aneurysms are rare Look for associated trauma/dissection Multiplanar CTA reformats is usually diagnostic Look for associated stenosis, contained thrombus Thromboembolic events best seen with MR (DWI for acute; FLAIR for chronic) SELECTED REFERENCES 1. Bridge KI et al: Images in vascular medicine. Delayed Horner's syndrome as a presenting symptom of traumatic internal carotid artery dissection and pseudoaneurysm. Vasc Med. 16(2):159-60, 2011 2. Herrera DA et al: Endovascular treatment of penetrating traumatic injuries of the extracranial carotid artery. J Vasc Interv Radiol. 22(1):28-33, 2011 3. Madan A et al: Traumatic carotid artery-cavernous sinus fistula treated with a covered stent. Report of two cases. J Neurosurg. 104(6):969-73, 2006 4. Gorriz-Gomez E et al: [Internal carotid artery pseudoaneurysm and stenosis: treatment with stents and coils.] Neurocirugia (Astur). 16(6):528-32, 2005 5. Mordekar SR et al: Occult carotid pseudoaneurysm following streptococcal throat infection. J Paediatr Child Health. 41(12):682-4, 2005 6. Koyanagi M et al: Stent-supported coil embolization for carotid artery pseudoaneurysm as a complication of endovascular surgery—case report. Neurol Med Chir (Tokyo). 44(10):544-7, 2004 7. Alexander MJ et al: Treatment of an iatrogenic petrous carotid artery pseudoaneurysm with a Symbiot covered stent: technical case report. Neurosurgery. 50(3):658-62, 2002 P.14:27

Image Gallery

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Diagnostic Imaging Cardiovascular (Left) Axial CECT of a 36-year-old patient with asymmetric palate and neck fullness shows a carotid space mass that represents markedly enlarged right ICA with normal enhancement in a dilated lumen (compare with normal left ICA at the bulb just above the bifurcation ). (Right) Axial T2WI MR at a similar level (same patient) with hypointense signal of lumen of ICA pseudoaneurysm reveals little thrombus in the wall of this pseudoaneurysm, with only marginal T2 hyperintensity.

(Left) Axial T1WI C+ FS MR with enhancement of the lumen of the dilated pseudoaneurysm of the right ICA reveals no obvious mural thrombus. The left ICA has a normal caliber. (Right) Axial CECT in a 74-year-old patient with longstanding pulsatile mass of the left neck shows peripheral calcifications as well as laminated layers of mural thrombus along the anterior and medial aspect of heterogeneous carotid space mass. The lumen is opacified with contrast and markedly dilated .

(Left) Axial T1WI MR (same patient) shows a carotid space mass with thickened irregular wall, and laminated mural thrombus . The patent lumen with flow is hypointense and irregularly ovoid , as in the prior image. (Right) Oblique DSA from a left common carotid artery injection, with a pseudoaneurysm sac filling slowly with contrast, shows the lumen of the ICA proximal and distal to the aneurysm with irregular “string of pearls” appearance secondary to fibromuscular disease.

Vertebral Dissection Key Facts Terminology Hemorrhage into damaged vessel wall with subsequent stenosis, pseudoaneurysm, rupture, or distal embolization Imaging 1140

Diagnostic Imaging Cardiovascular Key cross-sectional finding is crescentic hyperintensity of intramural hematoma on T1 FS MR Eccentric vertebral artery stenosis associated with intramural hematoma ± intimal flap Most common site is between C2 and skull base (V3-V4 segment) May occur along cervical (V1-V2) segment from trauma ± fracture involving foramen transversarium Irregular, often eccentrically narrowed vessel lumen with associated stenosis or pseudoaneurysm FS images most useful for diagnosis High-signal crescent or ring within vessel wall due to methemoglobin TOF images may have artifactual “pseudonormal” appearance from intramural methemoglobin (high-signal baseline, not flow-related enhancement) Smooth or slightly irregular, tapered luminal narrowing Recent reviews suggest near equivalency of CTA to MR and MRA DSA still considered gold standard Thin-section axial T1WI with fat saturation and inferior presaturation band May vary from mild stenosis to “string” sign to total occlusion Pathology Connective tissue diseases predispose to spontaneous dissection Sites of greatest mobility are susceptible to injury (e.g., V3 and V1 segments)

(Left) Left vertebral dissection is depicted. Axial CECT shows abnormal left vertebral artery with significant asymmetric narrowing of the vessel lumen along the anterior wall, representing intramural hematoma. The right vertebral artery is of normal caliber . (Right) Left vertebral dissection is shown. Axial CECT demonstrates intramural hematoma extending along the V3 segment of the left vertebral artery to the dural entry zone. The right vertebral artery is of small but consistent caliber .

(Left) Traumatic vertebral artery dissection is shown. MRA source image confirms patent internal carotids 1141

and right

Diagnostic Imaging Cardiovascular vertebral artery . The left vertebral artery has marked narrowing of flow-related enhancement of lumen. (Right) Traumatic vertebral artery dissection is demonstrated. Axial T1WI FS shows flow void within the right vertebral artery . The left vertebral artery has peripheral bright signal, indicating intramural hematoma. Bilateral internal carotid arteries have normal flow voids. P.14:29

TERMINOLOGY Abbreviations Vertebral artery dissection (VAD); spontaneous vertebral artery dissection (SVAD) Definitions Hemorrhage into damaged vessel wall with subsequent stenosis, pseudoaneurysm, rupture, or distal embolization IMAGING General Features Best diagnostic clue Key cross-sectional finding: Crescentic hyperintensity of intramural hematoma on T1 FS MR Intramural hematoma will lie eccentric to narrowed lumen Eccentric vertebral artery stenosis associated with intramural hematoma ± intimal flap Location Most common site is between C2 and skull base (V3-V4 segment) May extend into origin of posterior inferior cerebellar artery (PICA) Extension into subarachnoid space is significant concern and can lead to dissecting aneurysm May occur along cervical (V1-V2) segment from trauma ± fracture involving foramen transversarium Contemplate vertebral artery dissection with any significant cervical spine fracture dislocation CT Findings NECT Subarachnoid hemorrhage (SAH) ± focal clot adjacent to brainstem with intradural extension or dissecting aneurysm Posterior circulation infarction due to thromboembolism ± hemodynamic compromise Hyperdense subacute intramural or intraluminal thrombus termed “suboccipital rind” CTA Irregular, often eccentrically narrowed vessel lumen with associated stenosis or pseudoaneurysm Curvilinear intimal flap MR Findings T1WI FS images most useful for diagnosis; high-signal crescent or ring within vessel wall = methemoglobin Inferior presaturation slab very helpful to provide black blood of normal flow May occlude vessel; MRA or DSA may be helpful with marked narrowing of lumen FLAIR Sensitive for SAH if ruptured dissecting aneurysm or with infarction DWI Detect ischemic stroke due to thromboemboli or hemodynamic insufficiency MRA Variable appearances depending on degree of stenosis and morphology of pseudoaneurysm May see flow-related enhancement vs. signal loss if turbulent flow present Curvilinear intimal flap Normal or narrowed flow void (true lumen) TOF images may have artifactual “pseudonormal” appearance from intramural methemoglobin (highsignal baseline, not flow-related enhancement) May improve resolution with Gd-MRA; can augment with subtracted Gd-MRA Angiographic Findings DSA Smooth or slightly irregular, tapered luminal narrowing May vary from mild stenosis to “string” sign to total occlusion Pseudoaneurysm (25-35%) Intimal flap (10%) and double lumen Branch vessel occlusion from thromboembolism or extension of dissection into vessel origin (e.g., PICA)

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Diagnostic Imaging Cardiovascular Relationship of dissection to PICA and anterior spinal artery (ASA) origins from vertebral artery must be determined Imaging of contralateral vertebral artery is important to determine concurrent lesions and dominance of dissected vertebral artery Imaging Recommendations Best imaging tool Recent reviews suggest near equivalency of CTA to MR and MRA DSA still considered gold standard CTA with MIP reconstructions usually diagnostic MR including axial T1WI with fat saturation + TOF MRA will make diagnosis in most cases; Gd-MRA may have higher yield DSA in equivocal cases or in cases where endovascular treatment is contemplated (SAH, hemodynamically significant stenosis) Protocol advice Thin-section axial T1WI with fat saturation and inferior presaturation band DIFFERENTIAL DIAGNOSIS Atherosclerotic Disease Most common at vertebral artery origin More focal, mural calcifications; other vessels involved No intramural hematoma Fibromuscular Dysplasia Can present with focal narrowing on conventional angiogram Vertebral artery involvement (7%) is less common than involvement of carotid arteries (85%) Normal Dural Entry Zone Normal smooth concentric constriction of vertebral artery as it enters dura near skull base at V4 segment Dural entry zone is usually at foramen magnum but can be more caudal Subarachnoid Hemorrhage (SAH) Vasospasm Peaks 4-14 days post SAH P.14:30

PATHOLOGY General Features Etiology Spontaneous Hypertension: Primary or drug induced, including over-the-counter medication, e.g., ephedrine Major penetrating or blunt trauma, fractures Trivial trauma (coughing, sneezing, roller-coaster ride, chiropractic = classic) Prolonged or sudden neck hyperextension or rotation may be precipitating factor Iatrogenic from catheter angiography Intimal tear or ruptured vasa vasorum → intramural hematoma → stenosis or pseudoaneurysm → thrombus formation → thromboembolic events ± hemodynamic compromise Genetics CTDs predispose to spontaneous dissection Ehlers-Danlos syndrome, Marfan syndrome, autosomal dominant polycystic kidney disease Other arteriopathies Fibromuscular dysplasia Cystic medial necrosis Embryology and anatomy Vertebral artery is divided into 4 segments: V1 = origin to transverse foramen; V2 = transverse foramen to C2; V3 = C2 to dural entry; V4 = intradural segment Sites of greatest mobility are susceptible to injury (e.g., V3 and V1 segments) Microscopic Features Hematoma within tunica media of vessel wall Compressing intima and distending ± rupture through adventitia CLINICAL ISSUES Presentation Most common signs/symptoms Thromboembolic stroke 1143

Diagnostic Imaging Cardiovascular Other signs/symptoms SAH if intradural dissection and transmural extension Hemodynamic stroke/ischemia if significant stenosis and poor collaterals Dissection may affect other vessels if etiology is head/neck trauma or underlying collagen vascular disease Examine entire course of both carotid and vertebral arteries in such patients Neurological symptoms may be delayed Occipital headache and posterior neck pain Unilateral arm pain or weakness Brainstem, cerebellar infarction Lateral medullary syndrome of Wallenberg if PICA infarct Posterior cerebral artery territory infarction Homonymous hemianopsia or Anton syndrome (cortical blindness) if bilateral Demographics Age Affects all ages; peak in 5th decade of life High prevalence (10-25%) of etiology of infarcts in younger patients Epidemiology Estimate of 1-1.5 per 100,000 Carotid and vertebral dissections are responsible for 2% of all cerebrovascular accidents Natural History & Prognosis Spontaneous healing or recanalization in most cases Resolution or significant improvement of stenosis in 90% within 1st 2-3 months Treatment Anticoagulation, unless contraindications present If persistent ischemia Endovascular stent or surgical bypass If recurrent emboli without pseudoaneurysm despite anticoagulation Surgical ligation or endovascular occlusion if collateral blood flow sufficient If recurrent emboli with pseudoaneurysm Consider covered stent, stent-supported coil embolization, vessel sacrifice Dissecting pseudoaneurysm: Embolization or ligation DIAGNOSTIC CHECKLIST Consider Vertebral dissection in young patients with posterior circulation stroke Image Interpretation Pearls Look for cervical spine fractures that traverse transverse foramina MR, MRA, or CTA diagnostic in most cases SELECTED REFERENCES 1. Shea K et al: Carotid and vertebral arterial dissections in the emergency department. Emerg Med Pract. 14(4):1-23; quiz 23-4, 2012 2. Arnold M et al: Treatment issues in spontaneous cervicocephalic artery dissections. Int J Stroke. 6(3):213-8, 2011 3. Fusco MR et al: Cerebrovascular dissections—a review part I: spontaneous dissections. Neurosurgery. 68(1):242-57; discussion 257, 2011 4. Pham MH et al: Endovascular stenting of extracranial carotid and vertebral artery dissections: a systematic review of the literature. Neurosurgery. 68(4):856-66; discussion 866, 2011 5. Provenzale JM et al: Causes of misinterpretation of cross-sectional imaging studies for dissection of the craniocervical arteries. AJR Am J Roentgenol. 196(1):45-52, 2011 6. Ringer AJ et al: Screening for blunt cerebrovascular injury: selection criteria for use of angiography. J Neurosurg. 112(5):1146-9, 2010 7. Debette S et al: Cervical-artery dissections: predisposing factors, diagnosis, and outcome. Lancet Neurol. 8(7):66878, 2009 8. Provenzale JM et al: Comparison of test performance characteristics of MRI, MR angiography, and CT angiography in the diagnosis of carotid and vertebral artery dissection: a review of the medical literature. AJR Am J Roentgenol. 193(4):1167-74, 2009 9. Thorisson HM et al: Endovascular management of extracranial carotid and vertebral disease. Neurosurg Clin N Am. 20(4):487-506, 2009 10. Albuquerque FC et al: Endovascular management of intracranial vertebral artery dissecting aneurysms. Neurosurg Focus. 18(2):E3, 2005 P.14:31 1144

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Image Gallery

(Left) Restricted diffusion involving left cerebellar hemisphere is evident on this DWI image, confirming acute stroke in a 52-year-old patient with acute vertigo and nausea. (Right) Urgent diagnostic cerebral arteriography DSA image demonstrates a long segment of diffusely narrowed distal left vertebral artery , consistent with vertebral artery dissection involving the distal V3 and proximal V4 segments. No aneurysmal dilatation was evident.

(Left) Axial MRA (TOF) source image demonstrates a small intimal flap in a 26-year-old patient with neck pain and unremitting dizziness. The small intimal flap is evident in the vertebral artery in foramen transversarium. The contralateral vertebral artery is normal. (Right) Sagittal reformat MRA image of same patient shows long segment intimal flap . Subtle intimal injury may be best visualized on source image and MPR images, and it can occasionally be obscured or overlooked on MIP images.

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Diagnostic Imaging Cardiovascular

(Left) Axial CTA source image demonstrates “suboccipital rind” of intramural hematoma in the distal V3 segment of the left vertebral artery with abrupt narrowing of the lumen. (Right) Axial T1WI MR (same patient) shows high signal intensity of a subacute thrombus of the wall of the distal V3 segment of the left vertebral artery . This examination is performed without FS, which can be used to increase the conspicuity of intramural hematoma. Inferior presaturation pulses also improve luminal depiction.

Subclavian Steal Syndrome Key Facts Terminology Vertebral artery (VA) provides collateral blood flow to upper extremity because of vascular blockage Caused by stenosis/occlusion of proximal subclavian artery (SCA) or, occasionally, brachiocephalic artery Leads to reversed flow in VA to perfuse SCA distal to stenosis/occlusion Exacerbated by demand for increased arterial blood flow in arm supplied by affected SCA Imaging US is very reliable in diagnosing subclavian steal CTA, MRA, or DSA to confirm or delineate anatomy With MRA, use phase contrast technique to show flow direction/reversal in affected VA If abnormal VA flow is not detected at rest, then induce flow reversal with ipsilateral arm exercise or artificial arm hyperemia (after cuff compression) DSA usually combined with endovascular treatment Pathology Atherosclerosis is most common cause of SCA obstruction leading to subclavian steal Rarely, steal-inducing SCA obstruction may result from vasculitis, dissection, trauma, or vessel compression from adjacent neoplastic mass Clinical Issues Clinical profile: Diminished arm pulses and blood pressure ipsilateral to SCA obstruction Linear correlation between increasing arm blood pressure difference and occurrence of symptoms Usually involves left side (85%); can occur on right Conservative management is appropriate in asymptomatic or minimally symptomatic patients Address atherosclerosis risk factors SCA angioplasty/stenting is preferred over surgical bypass in symptomatic individuals

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(Left) Color Doppler US shows (A) normal antegrade arterial waveforms in the right vertebral artery, indicating appropriate blood flow directionality. (B) There is reversed directionality of the left vertebral artery waveform , indicating retrograde flow. (Right) Left anterior oblique DSA of the thoracic aortic arch shows occlusion of the left subclavian artery, proximal to the origin of the left vertebral artery. This is the typical anatomy that results in the subclavian steal phenomenon and is usually caused by atherosclerosis.

(Left) Delayed image from the aortic arch DSA demonstrates contrast opacification of the left vertebral artery and filling of the left subclavian artery beyond the occlusion. This is the classic DSA appearance of subclavian steal. (Right) (C) DSA after selective catheterization of the right vertebral artery shows contrast flowing retrograde into the left vertebral artery and reconstituting the left subclavian artery . (D) Yellow arrows on the graphic show the directionality of blood flow in subclavian steal phenomenon. P.14:33

TERMINOLOGY Definitions Vertebral artery (VA) provides collateral blood flow to upper extremity because of vascular blockage Caused by stenosis/occlusion of proximal subclavian artery (SCA) or, occasionally, brachiocephalic artery Leads to reversed flow in VA to perfuse SCA distal to stenosis/occlusion Exacerbated by demand for increased arterial blood flow in arm supplied by affected SCA IMAGING General Features Best diagnostic clue Reversed or biphasic VA flow ipsilateral to stenosed/obstructed SCA; antegrade flow in contralateral VA 1147

Diagnostic Imaging Cardiovascular Increased volume/velocity of flow in contralateral VA Location More common on left side but can occur on right Ultrasonographic Findings Duplex Doppler ultrasound (US) Mild subclavian steal (grade 1) Systolic deceleration of VA flow Moderate subclavian steal (grade 2) Biphasic (to-and-fro) flow in affected VA at rest Provocative dynamic tests with ipsilateral arm exercise or tourniquet-induced arm hyperemia may better demonstrate flow reversal Severe subclavian steal (grade 3) Reversed flow in affected VA Additional findings Increased blood flow in contralateral VA Not precisely defined, but peak systolic velocity > 60 cm/s suggests abnormality Damped Doppler waveforms in affected SCA Possible Doppler evidence of SCA stenosis Focal high velocity, turbulence CT Findings NECT May show atherosclerotic calcifications in vessel wall of stenotic or occluded proximal SCA Large plaques may show low-density foci (lipid) CECT High-grade SCA stenosis or occlusion Lesion must involve SCA proximal to VA origin CTA Permits 3D reconstruction of vasculature Allows better estimation of degree of stenosis May differentiate severe stenosis from occlusion MR Findings T1WI May identify high-signal lipid/hemorrhage in atherosclerotic plaque of stenosed SCA T2WI Wall thickening and luminal narrowing in SCA Absence of flow void may occur if vessel is severely stenotic or occluded MRA Determine degree of SCA stenosis With severe stenosis, intravascular signal may not be evident on noncontrast 2D time-of-flight MRA Can mimic SCA occlusion 3D C+ MRA is much better in delineating true presence and severity of SCA stenosis Determine flow direction in VA Reversed flow in VA will be inapparent on noncontrast 2D time-of-flight MRA Can mimic VA occlusion Due to superior saturation pulse used to remove inferiorly flowing venous signal 3D C+ MRA shows vessel patency, not flow direction Time-resolved 3D C+ MRA is better for showing retrograde VA flow Phase contrast MRA can confirm Vessel patency Reversal of VA flow Location of stenosis Angiographic Findings DSA Severe SCA stenosis or occlusion proximal to VA Reversed or to-and-fro flow in affected VA Antegrade flow in contralateral VA Best demonstrated on thoracic arch aortogram Usually combined with endovascular treatment 1148

Diagnostic Imaging Cardiovascular Imaging Recommendations Best imaging tool US is very reliable in diagnosing subclavian steal CTA, MRA, or DSA to confirm or delineate anatomy Protocol advice If abnormal VA flow is not detected at rest, then induce flow reversal with ipsilateral arm exercise or artificial arm hyperemia (following cuff compression) With MRA, use phase contrast technique to show flow direction/reversal in affected VA DIFFERENTIAL DIAGNOSIS Right Common Carotid Artery (CCA) Steal Associated with high-grade brachiocephalic artery stenosis/occlusion (right side only) Analogous to subclavian steal, but blood is “stolen” from right CCA as well as from right VA To-and-fro or reversed right CCA and right VA flow Vertebral Arteriovenous Fistula (AVF) Abnormal direct communication between vertebral artery and vein High-velocity turbulent flow with low resistance in affected vessels Surrounding venous engorgement May see reversal of VA flow distal to site of AVF Vertebral Artery Occlusion/Severe Stenosis Flow is not identified in VA; only venous flow is noted May be confused with slow reversal of flow in VA but will not demonstrate arterial waveform Adjacent vessels (usually from external carotid artery or proximal SCA) may mimic VA patency May even mimic reversal of VA flow Cervical collateral vessels can also reconstitute VA distal to occlusion/stenosis resulting in dampened distal VA and alternating or high-resistance flow pattern P.14:34

Vertebral Artery Hypoplasia May not detect normal VA flow in severe hypoplasia Usually on right side but may occur on left side Hypoplastic VA often supplies only ipsilateral posterior inferior cerebellar artery Hypoplastic left VA may arise directly from aortic arch Should demonstrate normal antegrade flow direction May have high-resistance flow pattern Due to increased flow friction in small vessel PATHOLOGY General Features Etiology Atherosclerotic occlusive disease by far most common cause of SCA obstruction leading to subclavian steal Rarely, steal-inducing SCA obstruction may result from vasculitis, dissection, trauma, or vessel compression from adjacent neoplastic mass Anatomy Unique vertebrobasilar arterial system permits subclavian steal: 2 VAs join to form basilar artery With proximal SCA occlusion/severe stenosis, blood is “stolen” from ipsilateral VA to perfuse arm Reversal of flow in ipsilateral VA and hyperdynamic flow in contralateral VA Usually requires ≥ 70% SCA diameter stenosis Staging, Grading, & Classification Grading of subclavian steal phenomenon Grade 0: No subclavian steal Normal antegrade VA flow Grade 1: Mild subclavian steal Systolic deceleration of VA flow Grade 2: Moderate subclavian steal Alternating (biphasic) flow in VA at rest Grade 3: Severe subclavian steal Reversed flow in affected VA 1149

Diagnostic Imaging Cardiovascular Clinical classification Complete (persistent): Subclavian steal phenomenon is always present Implies SCA occlusion/severe stenosis Intermittent: Subclavian steal phenomenon occurs only when arm exercise increases blood flow demand Implies moderate SCA stenosis CLINICAL ISSUES Presentation Most common signs/symptoms Generally harmless, asymptomatic phenomenon Can be symptomatic, especially during arm exercise Arm claudication (pain with arm exercise) If vertebrobasilar insufficiency is present, may cause dizziness (most common), vertigo, ataxia, diplopia, dysarthria, homonymous hemianopsia Other signs/symptoms Very rarely causes vertebrobasilar infarct of brainstem, cerebellum, or posterior cerebral hemispheres Concomitant carotid/vertebral/cerebral vascular disease is invariably present Angina may occur in patients who have undergone left internal mammary artery bypass surgery for coronary artery disease and have subclavian steal Known as coronary subclavian steal syndrome Myocardial ischemia due to reversed flow in internal mammary artery bypass graft Clinical profile Diminished arm pulses and blood pressure ipsilateral to SCA obstruction (differential of 20-30 mm Hg when comparing blood pressure in arms) Linear correlation between increasing arm blood pressure difference and occurrence of symptoms Usually involves left side (85%); can occur on right Demographics Age Older individuals (average age: 60 years) Atherosclerotic occlusive disease May occur in younger individuals with Takayasu arteritis causing SCA obstruction Gender M > F (slight male predominance) Natural History & Prognosis Usually remains asymptomatic May become symptomatic if atherosclerosis progresses in affected SCA/cerebral vasculature Treatment Conservative management is appropriate in asymptomatic or minimally symptomatic patients Address atherosclerosis risk factors SCA angioplasty/stenting is preferred over surgical bypass in symptomatic individuals Surgical bypass options include innominate-to-SCA, CCA-to-SCA, or axillary-to-axillary artery bypass DIAGNOSTIC CHECKLIST Consider Subclavian steal is likely if cerebral symptoms are exacerbated with arm exercise SCA obstruction is most likely due to atherosclerosis Must exclude vasculitis, dissection, adjacent neoplasm Image Interpretation Pearls Sonography is easiest and best test to confirm diagnosis If abnormal VA flow is not detected at rest, then induce flow reversal with ipsilateral arm exercise or hyperemia VA flow reversal will be inapparent on noncontrast 2D time-of-flight MRA; use C+ or phase contrast MRA SELECTED REFERENCES 1. Osiro S et al: A review of subclavian steal syndrome with clinical correlation. Med Sci Monit. 18(5):RA57-63, 2012 2. Song L et al: Endovascular stenting vs. extrathoracic surgical bypass for symptomatic subclavian steal syndrome. J Endovasc Ther. 19(1):44-51, 2012 3. Betensky BP et al: Unequal blood pressures: a manifestation of subclavian steal. Am J Med. 124(8):e1-2, 2011 4. Tan TY et al: Hemodynamic effects of subclavian steal phenomenon on contralateral vertebral artery. J Clin Ultrasound. 34(2):77-81, 2006 5. Sheehy N et al: Contrast-enhanced MR angiography of subclavian steal syndrome: value of the 2D time-of-flight “localizer” sign. AJR Am J Roentgenol. 185(4):1069-73, 2005 1150

Diagnostic Imaging Cardiovascular 6. Bitar R et al: MR angiography of subclavian steal syndrome: pitfalls and solutions. AJR Am J Roentgenol. 183(6):1840-1, 2004 P.14:35

Image Gallery

(Left) Axial CECT in a patient with dizziness and left arm claudication shows (A) a nonopacified proximal left subclavian artery , consistent with occlusion. (B) More cephalad, the distal left subclavian artery is opacified, indicating reconstitution via collateral blood flow. (Right) Coronal CT reconstruction shows atherosclerotic calcification and segmental occlusion of the proximal left subclavian artery. The distal left subclavian artery is reconstituted via a large left vertebral artery .

(Left) Preferred treatment of a symptomatic subclavian steal due to a severely stenotic or occluded subclavian artery is via endovascular revascularization. DSA shows that the subclavian occlusion has been recanalized and an intravascular stent has been placed, with care taken to preserve patency of the vertebral artery . (Right) DSA of the thoracic aortic arch following endovascular revascularization shows a patent stent and normal antegrade filling of the left vertebral and subclavian arteries.

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(Left) Although subclavian steal usually occurs on the left, right-sided cases also occur. Color Doppler US shows (A) reversed flow in the right VA and (B) biphasic internal carotid artery flow , worrisome for brachiocephalic artery obstruction in a patient with dizziness and right arm claudication. (Right) Thoracic aorta DSA shows a severely stenotic brachiocephalic artery & a faintly opacified right subclavian artery . Retrograde flow via the right VA and CCA collateralizes the subclavian artery.

Section 15 - Renal Vasculature Approach to Renal Vasculature Introduction The kidneys receive roughly 15% of the cardiac output via the renal arteries. By perfusing the kidneys, the renal arteries have an essential role in the renal processes of detoxification and fluid regulation. The renal vasculature is susceptible to a variety of pathologic processes. Knowledge of the normal renal arterial and venous anatomy is essential to understanding and evaluating the various disease processes that may affect the renal vasculature. Similarly, familiarity with the unique pathologic processes that involve the renal vasculature is necessary for appropriate evaluation and treatment. Anatomic Considerations Renal Arteries The kidneys are supplied by the renal arteries, which arise from the right and left lateral aspects of the abdominal aorta at approximately the level of the second lumbar vertebra. In the majority of individuals, each kidney is supplied by a single main renal artery. Each renal artery is typically 5-6 mm in diameter and 4-6 cm long. The right renal artery arises from the anterolateral aspect of the aorta and then courses posterior to both the inferior vena cava (IVC) and the right renal vein. The left renal artery arises slightly more laterally from the aorta than its counterpart on the right and also courses posterior to the corresponding renal vein. The proximal portion of the main renal artery gives off small-caliber branches that arise from its superior aspect to supply the adrenal gland (inferior adrenal artery) and the renal capsule (capsular artery). The renal artery courses toward the renal pelvis, where it bifurcates into anterior and posterior divisions. The former lies anterior to the renal pelvis and supplies the upper and lower poles along with the anterior aspect of the mid portion of the kidney. The posterior division lies behind the renal pelvis and perfuses the posterior aspect of the kidney. Accessory or supernumerary renal arteries are noted in up to 40% of patients and typically arise from the abdominal aorta but may also occasionally originate from the common iliac or even, rarely, the external iliac arteries. Renal Veins Each kidney is normally drained by a single renal vein, each of which joins the IVC. The right renal vein, which is shorter than the left, courses anterior to the right renal artery to drain into the IVC. The left renal vein courses between the abdominal aorta and the superior mesenteric artery (SMA) to join the IVC. Communications between the renal veins and other retroperitoneal veins occur commonly. The left gonadal vein drains directly into the left renal vein in almost all individuals, whereas the right gonadal vein rarely joins the renal vein but instead joins the IVC in more than 90% of patients. Abnormalities of the Renal Arteries 1152

Diagnostic Imaging Cardiovascular Aneurysms and Pseudoaneurysms Renal artery aneurysms may be congenital (rare) or acquired. Of the latter, degenerative aneurysms in association with atherosclerosis are most common. Multiple small renal artery aneurysms may also occur in association with polyarteritis nodosa. Most renal artery aneurysms are small and are generally asymptomatic. However, there are known complications associated with aneurysms such as rupture, spontaneous thrombosis, and distal embolization. Pseudoaneurysms typically occur in association with tumors such as angiomyolipoma, or they may be iatrogenic or post-traumatic in nature. They may also be associated with primary disease processes affecting the arterial wall such as fibromuscular dysplasia and segmental arterial mediolysis. Arteriovenous Communications The various types of renal arteriovenous (AV) communications include arteriovenous malformation (AVM), arteriovenous fistula (AVF), and arteriovenous tumoral shunting. AVMs are always congenital, whereas AVFs may be congenital or acquired, with the etiology of the latter being either iatrogenic or traumatic. Arteriovenous tumoral shunting classically occurs in renal cell carcinoma. Atherosclerosis This is the most common disease affecting the cardiovascular system and develops as a result of an inflammatory response of the vascular endothelium to the accumulation of fatty materials, such as cholesterol and triglycerides, in the arterial wall. Various factors contribute to the eventual development of atheromatous plaque in the arterial wall. Plaque in the renal arteries most often decreases perfusion to the kidneys through the development of stenoses or thrombotic occlusion, but distal embolization and infarction may also occur. Fibromuscular Dysplasia Fibromuscular dysplasia (FMD) is a noninflammatory, nonatherosclerotic vasculopathy that involves medium-caliber arteries and is characterized by fibrous thickening of the arterial wall due to segmental areas of collagen deposition and smooth muscle overgrowth. Although this may affect any layer of the arterial wall, the arterial media is involved in > 80% of cases. The renal arteries are the most frequently affected vessels and are involved in up to 75% of all patients with FMD. Women are affected far more frequently than men, typically in the 30-50 years age range. FMD may lead to stenosis, dissection, or aneurysms of the renal arteries and is a well-recognized cause of renovascular hypertension. Segmental Arterial Mediolysis This nonatherosclerotic and noninflammatory arteriopathy typically affects the mesenteric arteries but may also involve the renal arteries. It is characterized by multiple dissections and aneurysms that can lead to arterial occlusion with subsequent end-organ infarction of the bowel or kidneys. It has been postulated that this entity may be related to fibromuscular dysplasia, and often the two entities are difficult to differentiate by imaging. Histology shows vacuolar degeneration of the smooth muscle in the outer media of the arterial wall; this can result in separation of arterial media from the adventitia and the formation of arterial gaps. Clinical symptoms include acute abdominal pain and hemorrhage in late middle-aged or elderly patients. Because of the deficient arterial wall, segmental arterial mediolysis responds poorly to angioplasty and other interventions. Stenosis The most common etiology of renal artery stenosis (RAS) is atherosclerosis, which typically affects the P.15:3 artery proximally. However, RAS may also occur in association with fibromuscular dysplasia, segmental arterial mediolysis, Takayasu arteritis, neurofibromatosis type 1, William syndrome, Marfan syndrome, congenital Rubella syndrome, Kawasaki disease, and Crohn disease. Regardless of the etiology, RAS typically manifests in the form of renovascular hypertension. Narrowing of the renal artery(ies) results in a low renal perfusion pressure, which is detected by the baroreceptors of the juxtaglomerular apparatus (located on the afferent arteriole wall), leading to renin secretion. This causes the conversion of angiotensinogen to angiotensin I, which is then converted in the lung to angiotensin II via angiotensin-converting enzyme (ACE). Angiotensin II causes vasoconstriction and aldosterone release, leading to the retention of water and sodium and the depletion of potassium. The increased blood volume and vessel constriction leads to increased blood pressure and, ultimately, to hypertension. Thrombosis/Acute Arterial Occlusion Renal artery thrombosis may occur as a result of trauma, infection/inflammation, atherosclerosis, aneurysm, tumor, or FMD. If a normal renal artery becomes acutely occluded, this causes renal ischemia that requires urgent revascularization to preserve renal function. In elderly individuals, acute occlusion is most commonly caused by an embolus, whereas in younger patients the most likely etiology is trauma. However, if acute occlusion is due to thrombosis of a preexisting critical renal artery stenosis, there are usually substantial collaterals present that developed as a result of the chronic occlusive disease. In such cases, the resultant renal ischemia is much better tolerated. Trauma

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Diagnostic Imaging Cardiovascular The renal arteries are susceptible to penetrating and blunt trauma or may be damaged through a deceleration injury. Penetrating injuries may lead to AVFs, intrarenal/subcapsular hematomas, pseudoaneurysms, or frank retroperitoneal hemorrhage. Blunt trauma results in a renal fracture with involvement of the intrarenal or extrarenal arteries and may lead to the same pathologic sequelae as a penetrating injury. Iatrogenic injuries secondary to surgical or interventional procedures are also well-recognized causes of various renal arterial abnormalities. Vasculitis Although Takayasu arteritis typically affects the aorta and great vessels, it is known to involve the pararenal segment of the aorta and the renal arteries themselves, manifesting typically as an inflammatory renal artery stenosis. Vascular involvement in neurofibromatosis type 1 may also have a pararenal and renal artery distribution, may cause renal artery stenosis, and may thus mimic Takayasu arteritis. Polyarteritis nodosa or Kussmaul disease, a vasculitis involving small and medium-sized arteries, may also involve the renal arteries and is characterized by multiple small aneurysms that may appear to be strung like rosary beads. There is a known association with hepatitis B and with intravenous drug use. Giant cell arteritis, which most commonly affects the temporal arteries, may also involve the renal arteries and may be associated with a variety of renal lesions, including necrotizing arteritis, necrotizing glomerulonephritis, granulomatous glomerulonephritis, and membranous glomerulopathy. It is a rare but known cause of renal failure. Abnormalities of the Renal Veins Anatomic Variants Variant anatomy involving the renal veins may occur in up to 40% of individuals. The most common variant is that of multiple right renal veins, which occurs in almost one-third of cases. A circumaortic left renal vein, in which separate venous components course both anterior and posterior to the abdominal aorta, is the second most common anatomic variant and occurs in 5-7% of individuals. Less than 5% of patients have a retroaortic left renal vein. Both circumaortic and retroaortic renal venous anatomy may produce symptoms in some patients as a result of venous compression and outflow obstruction. Arteriovenous Communications When AV communications, such as AVM, AVF, and arteriovenous tumoral shunting, involve the renal vasculature, excessively high flow may occur in the renal veins and may lead to the development of renal venous hypertension, which may result in renal vein varices, pain, hematuria, and rarely, high-output cardiac failure. Thrombosis Although renal vein thrombosis has numerous etiologies, it most commonly occurs in patients with nephrotic syndrome. Other well-known primary causes include dehydration, a hypercoagulable state, and membranous or membranoproliferative glomerulonephritis. Various secondary causes of renal vein thrombosis include trauma, extrinsic compression, oral contraceptive use, and pregnancy. Renal dysfunction, hematuria, and back pain may occur with acute renal vein thrombosis, and if the thrombosis is sufficiently extensive, permanent renal ischemic injury may ensue. Trauma The renal veins may be damaged as a result of either blunt or penetrating trauma to the abdomen. Although the renal veins are part of a low-pressure system, there is nonetheless a potential for significant hemorrhage with severe injury. Tumor Thrombus Tumor thrombus may extend from a renal neoplasm into the renal vein and IVC. The most common etiology is renal cell carcinoma, with thrombus in the renal vein reported in up to 20% of cases. The tumor thrombus may additionally extend from the renal vein into the IVC in 4-15% of patients. Symptoms may vary according to the degree to which the tumor thrombus obstructs the renal vein. Varices Various processes may result in renal venous hypertension, which may then lead to the development of renal vein varices. If these are sufficiently severe, patients may experience back, flank, &/or pelvic pain as well as hematuria. When present, varices more commonly involve the left kidney and renal vein than the right. There are numerous wellrecognized causes of these varices, such as arteriovenous communications, highly vascular renal tumors, venous malformations, and spontaneous gastrorenal or splenorenal shunts, that may develop in association with gastric varices and portal hypertension. P.15:4 Severe compression of a circumaortic or retroaortic renal vein may also lead to symptomatic varices, as may extrinsic compression of the left renal vein between the SMA and the abdominal aorta. This latter form of renal vein compression, if symptomatic, is known as nutcracker syndrome, and in addition to causing renal vein varices, it may lead to dilatation and reversal of flow in the left gonadal vein and the development of pelvic varices and pelvic congestion syndrome. Imaging of the Renal Vasculature Ultrasound 1154

Diagnostic Imaging Cardiovascular Color Doppler ultrasound (US) is usually the first-line screening examination in patients in whom a renovascular etiology for hypertension is suspected, and it has a sensitivity of 85% and a specificity of 90%. During the examination, the arterial waveforms of various segments of the renal arteries, including the intrarenal vessels, are evaluated. A normal waveform obtained from the main renal artery demonstrates a rapid upstroke in systole and a low-resistance waveform with continuous forward flow throughout the cardiac cycle. The normal peak systolic velocity (PSV) in the main renal artery should be < 150 cm/s, with a naturally occurring decrease in the velocity in the distal intrarenal arteries. Elevation of the renal artery PSV above 200 cm/s signifies the presence of a hemodynamically significant stenosis, as does elevation of the ratio of the renal artery PSV to that of the abdominal aorta above 3.5. There are other parameters that are assessed during renal artery US, such as the renal artery resistive index (RI). This is a ratio of the peak systolic and end-diastolic velocities and is normally < 0.7. The RI tends to be elevated in patients with chronic medical renal disease or in those with renal damage due to a long history of hypertension. Patients with an abnormally elevated RI are unlikely to benefit from an intervention such as angioplasty or stenting. Computed Tomography Angiography Computed tomography angiography (CTA) has the advantages of accurately delineating vascular anatomy with excellent 3D spatial resolution. Additionally, multiplanar reformatted images can be routinely obtained, thereby demonstrating not only the vasculature but also the relationship to the surrounding structures. CT is able to evaluate patients with renal artery atherosclerotic lesions. However, calcified atherosclerotic plaques typically limit the accurate measurement of arterial luminal calibers. Furthermore, the presence of a metallic intravascular stent may cause significant artifact that may also limit the accuracy of CTA, although the assessment of vascular patency may still be achieved with wide window and level settings or by using dual-energy CT. Other disadvantages of CTA include the potential for contrast-induced nephropathy and the requisite exposure to ionizing radiation. Magnetic Resonance Angiography Magnetic resonance angiography (MRA) with intravenous contrast can be highly sensitive and specific in the evaluation of the renal vasculature, without exposure to ionizing radiation and with a lack of calcium-related artifacts. Unfortunately, however, MRA can be limited by artifacts related to intravascular metallic stents and may not be tolerated by claustrophobic patients. In addition, MRA is more expensive and often less readily available than other imaging modalities. Furthermore, gadolinium-enhanced MRA is contraindicated in patients with severe renal dysfunction as there is a significant risk of developing nephrogenic systemic fibrosis. Fortunately, recently developed sequences now allow the use of noncontrast MRA to obtain high-quality images of the vasculature. Nuclear Medicine Radionuclide imaging can provide functional information about renal perfusion from which the presence or absence of an obstructing vascular lesion may be inferred. Although decreased glomerular filtration of a radioisotope-labeled agent following the administration of an ACE inhibitor such as captopril is highly suggestive of a renal artery stenosis, this imaging modality is much less frequently used than previously. Digital Subtraction Angiography Digital subtraction angiography (DSA) remains the gold standard for evaluating the renal arteries and veins. In most instances, however, the renal arteries &/or veins are initially imaged with less invasive modalities, such as US, CTA, and MRA. Diagnostic DSA is now generally used for confirmation or clarification of an abnormality seen on noninvasive imaging or for further evaluation in a case in which there remains a highly suspicious clinical scenario for a vascular abnormality but the initial imaging studies are negative. In many cases, the most important role of DSA is that of providing imaging guidance during a catheter-based endovascular intervention aimed at treating an arterial or venous abnormality that has been identified by another imaging modality. Endovascular interventions that are routinely used for treating abnormalities of the renovascular structures include angioplasty, intravascular stenting, renal artery denervation, and transcatheter embolization. Selected References 1. Angeretti M et al: Non-enhanced MR angiography of renal arteries: comparison with contrast-enhanced MR angiography. Acta Radiol. Epub ahead of print, 2013 2. Park UJ et al: Use of early postoperative MAG3 renal scan to predict long-term outcomes of renal transplants. Exp Clin Transplant. 11(2):118-21, 2013 3. AbuRahma AF et al: Critical analysis of renal duplex ultrasound parameters in detecting significant renal artery stenosis. J Vasc Surg. 56(4):1052-9, 1060, 2012 4. Leschied JR et al: 99mTc MAG3 renography demonstrating return to normal renal function following resolution of renal vein thrombosis. Clin Nucl Med. 37(4):382-4, 2012 5. Mousa AY et al: Short- and long-term outcomes of percutaneous transluminal angioplasty/stenting of renal fibromuscular dysplasia over a ten-year period. J Vasc Surg. 55(2):421-7, 2012 6. Pei Y et al: Evaluation of renal artery in hypertensive patients by unenhanced MR angiography using spatial labeling with multiple inversion pulses sequence and by CT angiography. AJR Am J Roentgenol. 199(5):1142-8, 2012 7. Kalva SP et al: Segmental arterial mediolysis: clinical and imaging features at presentation and during follow-up. J Vasc Interv Radiol. 22(10):1380-7, 2011 1155

Diagnostic Imaging Cardiovascular 8. O'Neill WC et al: Imaging for renovascular disease. Semin Nephrol. 31(3):272-82, 2011 9. Spyridopoulos TN et al: Ultrasound as a first line screening tool for the detection of renal artery stenosis: a comprehensive review. Med Ultrason. 12(3):228-32, 2010 P.15:5

Image Gallery

(Left) US is usually the initial imaging modality used to evaluate the renal arteries, particularly if a renovascular etiology for hypertension (e.g., renal artery stenosis) is suspected. Signs of a renal artery stenosis include a peak systolic velocity ≥ 200 cm/s and a renal artery:aortic peak systolic velocity ratio ≥ 3.5. (Right) US is also used to assess the intrarenal arteries for indirect signs of a proximal stenosis. These include a tardus-parvus waveform , prolonged acceleration time (> 0.07 seconds), and loss of early systolic peak .

(Left) 3D CTA reconstruction of the abdominal aorta and renal arteries shows severe proximal stenoses of both renal arteries, confirming the findings from the screening US. Proximal stenoses such as these are typically due to atherosclerosis. (Right) DSA aortogram also confirms bilateral renal artery stenoses . Although DSA is considered the gold standard for diagnosing renal artery stenoses, it is now typically reserved for clarifying equivocal cases or for providing guidance during endovascular interventions.

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(Left) DSA during right renal artery stenting shows that the tip of a catheter has been positioned at the renal artery origin. The stenosis will be carefully crossed with a guidewire, and a stent will be placed, spanning the entire stenosis and protruding slightly into the aortic lumen. (Right) DSA after bilateral renal artery stenting shows satisfactory stent positions and no residual stenosis or occlusion. Stenting is definitively better than angioplasty alone for treating renal artery stenoses that are secondary to atherosclerosis. P.15:6

(Left) Coronal MRA shows a beaded appearance to the middle and distal segments of the right renal artery. The findings are highly suspicious for renal artery fibromuscular dysplasia. The left renal artery is suboptimally assessed; thus, a renal arterial lesion cannot be excluded with certainty. (Right) DSA of the abdominal aorta confirms the MRA findings in the right renal artery and also suggests FMD involvement of the left renal artery . These lesions are typically very responsive to angioplasty and rarely require stenting.

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(Left) Axial CECT shows an enhancing mass with a circumferential rim of calcification in the left kidney and an adjacent smaller calcified mass more peripherally. Findings are consistent with calcified intrarenal aneurysms arising from the left renal artery. (Right) MRA confirms the left renal aneurysm and shows a complex vascular abnormality in the right kidney. There is simultaneous opacification of serpiginous arterial and venous structures , indicating AV communication.

(Left) Early arterial phase DSA of the abdominal aorta also demonstrates the smaller calcified left renal aneurysm and shows smaller intrarenal aneurysms in the right kidney. There is also early opacification of dilated right intrarenal venous structures . (Right) Slightly later phase abdominal aorta DSA shows filling of the larger left renal aneurysm and shows dense opacification of dilated draining veins on the right. Findings are consistent with AVFs with associated calcified aneurysms, likely congenital. P.15:7

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(Left) Coronal NECT reconstruction in a patient with persistent gross hematuria after percutaneous lithotripsy shows a rim of peripheral high attenuation in an enlarged left kidney, consistent with a subcapsular hematoma. (Right) Left renal artery DSA shows lobulated intrarenal contrast collections in the lower renal pole, which was the site of percutaneous access for the lithotripsy. The appearance is consistent with pseudoaneurysm and represents an iatrogenic injury to intrarenal arterial branches.

(Left) DSA of left renal artery lower pole branch using a coaxial microcatheter shows (A) the pseudoaneurysm and supplying arterial branch . (B) The microcatheter has been advanced into the pseudoaneurysm, and embolization coils have been placed. (Right) DSA after coil embolization shows the pseudoaneurysm has been occluded and the majority of the normal renal parenchyma has been preserved. Iatrogenic renal artery injuries are well-recognized complications of percutaneous procedures.

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(Left) Right renal artery DSA in a patient who had flank pain and hematuria after a motor vehicle accident shows marked irregularity to the vessel. The right renal artery crosses anterior to the spine and is vulnerable to a stretching injury during severe deceleration, potentially leading to intimal injury and dissection. This can lead to arterial thrombosis and irreversible renal ischemia if not treated promptly. (Right) DSA shows a covered stent has been placed across the injured arterial segment, thus restoring arterial integrity.

Renal Vasculature Anatomy GROSS ANATOMY Renal Arteries Kidney is supplied by 1 renal artery in most individuals Renal artery usually 5-6 mm in diameter, 4-6 cm long 30-40% incidence of multiple renal arteries More common on right side if present Renal arteries arise from abdominal aorta at ˜ L2 level Right renal artery arises anterolaterally from aorta Slightly longer than left renal artery Courses posterior to both inferior vena cava (IVC) and right renal vein Left renal artery arises laterally from aorta Courses posterior to corresponding renal vein Main renal arteries divide at renal hilum into anterior and posterior segmental arteries Intrarenal Arterial Anatomy Anterior segmental artery supplies upper, middle, and lower segments of kidney Usually also supplies apical segment Posterior segmental artery usually supplies only posterior segment of kidney May supply apical segment in minority of patients Segmental arteries yield interlobar arteries Course alongside renal pyramids toward periphery Yield arcuate arteries at corticomedullary junction Arcuate arteries travel across top of renal pyramids and give rise to interlobular arteries Interlobular arteries are tiny parenchymal branches that course toward kidney surface and subdivide into afferent glomerular arterioles Branches of Renal Arteries Inferior adrenal artery Arises superiorly from proximal main renal artery Supplies inferior aspect of adrenal gland Adrenal gland is also supplied by middle adrenal artery arising from aorta and superior adrenal artery originating from inferior phrenic artery Superior capsular artery Arises adjacent to, or with, inferior adrenal artery Primarily supplies perirenal (capsular) fat 1160

Diagnostic Imaging Cardiovascular May anastomose with retroperitoneal arterial plexus Plexus is derived from several tiny aortic branches Communicates with intrarenal arteries via perforating branches Middle capsular artery Arises from main renal artery or its branches Medial course toward renal sinus; gives off branches that supply ventral and dorsal perirenal fat Perforating middle capsular arteries arise from renal interlobular arteries, penetrate capsule, and anastomose with perirenal branches May be difficult to distinguish from ureteric artery Inferior capsular artery Commonly arises from gonadal artery Usually not well developed When present, anastomoses with superior capsular artery; forms arcade along lateral margin of kidney Arcade communicates with perforating capsular arteries and other retroperitoneal arteries Capsular arteries may provide collateral flow to kidney Occurs with severe renal artery stenosis/occlusion located distal to capsular artery origin Exophytic renal neoplasms may derive portion of arterial supply from these vessels e.g., angiomyolipoma, renal cell carcinoma Ureteric arteries Superior ureter is supplied by branches arising from renal, inferior adrenal, or testicular artery Distal ureter is supplied by tiny branches from common, internal, and external iliac arteries May provide collateral flow to kidneys in presence of renal artery stenosis/occlusion Enlarged collaterals may cause “ureteral notching” Variant Renal Arterial Anatomy 30-40% incidence of variations in number, location, and branching patterns of renal arteries Accessory renal arteries usually arise from aorta May arise from common iliac arteries Rarely arise above superior mesenteric artery (SMA) Horseshoe kidneys always have multiple renal arteries Fused portion of horseshoe kidney (isthmus) may be supplied by distal aorta and iliac arteries Other congenital variations in renal configuration/position (e.g., pelvic kidney, crossed fused ectopia) have high incidence of variant arterial anatomy Renal Veins Usually each kidney is drained by single renal vein Right renal vein drains directly into IVC Multiple right renal veins occur in 28% of patients Right gonadal vein drains into right renal vein in < 10% of individuals Right adrenal vein drains directly into IVC rather than into right renal vein Left renal vein courses between aorta and SMA Enters IVC directly opposite right renal vein In 99% of individuals, left gonadal vein drains into left renal vein before latter crosses aorta Left adrenal and inferior phrenic veins drain into left renal vein, usually via common trunk Compression of left renal vein between aorta and SMA can result in nutcracker syndrome Variant Renal Venous Anatomy Circumaortic left renal vein is most common variant Vein divides; encircles aorta anteriorly & posteriorly Each venous moiety enters IVC separately Occurs in ˜ 2-6% of patients Retroaortic left renal vein is another common variant Vein courses posterior to aorta to enter IVC May be compressed between aorta and spine, causing left renal vein outflow obstruction Implications for optimal IVC filter placement RELATED REFERENCES 1. Kang WY et al: Perihilar branching patterns of renal artery and extrarenal length of arterial branches and tumourfeeding arteries on multidetector CT angiography. Br J Radiol. 86(1023):20120387, 2013 2. Khamanarong K et al: Anatomy of renal arterial supply. Clin Anat. 17(4):334-6, 2004 3. Hoeltl W et al: Renal vein anatomy and its implications for retroperitoneal surgery. J Urol. 143(6):1108-14, 1990 4. Meyers MA et al: The significance of the renal capsular arteries. Br J Radiol. 40(480):949-56, 1967 P.15:9 1161

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Image Gallery NORMAL RENAL ARTERIAL AND VENOUS ANATOMY

Graphic shows the normal renal arterial and venous anatomy. Each kidney is typically supplied by a single renal artery and is drained by a single renal vein, although variations in both arterial and venous anatomy are fairly common. The right renal artery and left renal vein are each longer than their counterparts as a result of their relationships to the abdominal aorta and inferior vena cava (IVC), respectively. Each renal artery yields several small branches proximally, including the inferior adrenal, capsular, and ureteric arteries. These vessels can provide important collateral perfusion to the kidney in some cases of stenosis or occlusion of the main renal artery. The left renal vein courses between the aorta and superior mesenteric artery (SMA) to enter the IVC directly opposite the right renal vein. The left gonadal vein drains into the left renal vein while its counterpart on the right enters the IVC directly. P.15:10

NORMAL RENAL ARTERIAL ANATOMY

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(Top) Graphic shows normal renal arterial anatomy. The adrenal artery arises from the proximal main renal artery. It often has a common trunk with the superior capsular artery, which supplies the perirenal fat. Normally, the main renal artery extends to the hilum before branching into the segmental renal arteries. The segmental renal arteries yield the interlobar arteries, which course alongside the renal pyramids toward the periphery where they give off the arcuate arteries. The latter run across the top of the renal pyramids and give rise to the interlobular arteries (parenchymal branches that course toward the kidney surface and subdivide into the afferent glomerular arterioles). (Bottom) Left renal arteriogram shows a normal arterial branching pattern. The anterior segmental renal artery supplies the anterior, upper, middle, and lower segments; the posterior segmental artery supplies the posterior segment. The superior capsular artery courses over the upper renal pole and anastomoses with small retroperitoneal branches. Here, the superior capsular artery has a separate origin from the inferior adrenal artery. The middle capsular artery arises from the main renal artery and gives supply to the renal pelvis and proximal ureter. P.15:11

NORMAL RENAL VENOUS ANATOMY

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(Top) Graphic shows the normal extrarenal vascular structures related to the venous drainage of the kidneys. Normally, each kidney is drained by a single renal vein, although multiple renal veins may (more common on the right). Variant venous anatomy is particularly prevalent on the left; common variants include circumaortic and retroaortic renal veins. Any retroaortic component of the left renal vein is susceptible to compression between the aorta and the underlying vertebra, potentially causing left renal vein outflow obstruction. Also, the left renal vein can be compressed between the aorta and SMA, causing nutcracker syndrome. (Bottom) Left renal venogram shows detailed normal anatomy of the intrarenal and extrarenal veins. The branching pattern of the intrarenal veins corresponds to that of the intrarenal arterial circulation. The left kidney is drained by a single renal vein that courses across the midline to drain into the IVC opposite the right renal vein. The latter drains directly into the IVC. The left adrenal gland is drained by a single adrenal vein that joins with the inferior phrenic vein to drain into the superior aspect of the left renal vein via a common trunk, while the right adrenal vein drains directly into the IVC via a short venous trunk.

Renal Artery Atherosclerosis Key Facts Imaging Focal or segmental luminal narrowing of renal artery Smaller ipsilateral kidney Doppler ultrasound Increased peak systolic velocity: 100-200 cm/s → < 50% stenosis; > 200 cm/s → 50-99% stenosis Renal to aortic ratio of peak systolic velocity: > 3.5 1164

Diagnostic Imaging Cardiovascular Pulsus parvus et tardus in distal vessels CT/MR/angiography: Renal artery narrowing of > 50% within 2 cm of ostium Angiography is gold standard for diagnosis and intervention Top Differential Diagnoses Arterial dissection Vasculitis Thromboembolism Fibromuscular dysplasia Pathology ≥ 50% narrowing of renal artery diameter is thought to be hemodynamically significant Clinical Issues Hypertension Progressive or acute renal impairment Treatment Medical management Intervention may be indicated when ≥ 1 primary renal functions are affected Endovascular management with renal artery angioplasty &/or stent placement Surgical management with aortorenal bypass or nephrectomy Treatment of stenosis can result in resolution, improvement, or no change in hypertension

(Left) Oblique color Doppler ultrasound of a patient's right renal artery shows high peak systolic velocity at the right renal artery origin, consistent with > 50% stenosis. A peak systolic velocity > 200 cm/s is considered abnormal. (Right) Sagittal color Doppler ultrasound of the same patient's right kidney shows Doppler waveform in the arcuate artery. There is a tardus et parvus waveform within the arcuate artery distal to the stenosis, which confirms the hemodynamic significance of the stenosis.

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Diagnostic Imaging Cardiovascular (Left) Oblique 3D reconstruction of CT angiography data in a patient with hypertension shows focal high-grade stenosis of the left renal artery at its ostium. Note poststenotic dilatation. In addition, the plaque extends into the aortic lumen at the renal artery origin. (Right) Oblique 3D reconstruction (maximum-intensity projection) in the same patient shows focal stenosis at the origin of the left renal artery. Note extensive calcifications within the aorta. P.15:13

TERMINOLOGY Synonyms Atherosclerotic renal artery stenosis Renal artery stenosis (RAS) Definitions Narrowing or occlusion of renal artery lumen IMAGING General Features Best diagnostic clue Focal or segmental luminal narrowing of renal artery Smaller ipsilateral kidney Location Renal artery ostium or within proximal 2 cm Renal artery branch involvement is not common Can be bilateral in up to 75% of patients Size Discrepancy in renal size of > 2 cm Radiographic Findings Radiography Asymmetric renal shadows Smaller kidney has RAS Aortic or renal artery calcification IVP Kidney: Normal (mild RAS); atrophic (high-grade stenosis or occlusion) Delayed/absent nephrogram Increased density or persistent nephrogram Delayed contrast excretion and clearing from collecting system Ureteral notching from collateral arteries CT Findings NECT Unilateral or bilateral renal atrophy Aortic and renal artery wall calcification Calcified hard plaque; low-density soft plaque CECT Delayed nephrogram and contrast excretion Hyperdense or persistent nephrogram Cortical and parenchymal thinning CTA Renal artery narrowing within 2 cm of ostium Truncal RSA beyond proximal 2 cm Poststenotic dilatation Locations and origins of all renal arteries can be seen Periureteric collaterals MR Findings T1WI Small kidney with variable signal intensity Absent corticomedullary differentiation Cortical and secondary parenchymal thinning T2WI Small kidney with variable signal intensity T1WI C+ Decreased and delayed nephrogram 1166

Diagnostic Imaging Cardiovascular Ultrasonographic Findings Grayscale ultrasound Smaller kidney with chronic, significant stenosis Increased echogenicity of parenchyma Pulsed Doppler Increased peak systolic velocity (PSV): 100-200 cm/s → < 50% stenosis; > 200 cm/s → 50-99% stenosis Renal to aortic ratio of PSV is > 3.5 Poststenotic turbulence and spectral broadening ± flow reversal Absent flow denotes occlusion Distal to stenosis: Pulsus tardus et parvus Low PSV with delayed acceleration Resistive index: < 5% on affected side compared with normal side Color Doppler Color aliasing at stenosis (systolic turbulence) Soft tissue “thrill” or vibration Nuclear Medicine Findings Angiotensin-converting enzyme (ACE) inhibitor renography Delayed radiotracer uptake and excretion in affected kidney; time to peak is > 30 minutes Ratio of 20 min/peak cortical activity is > 0.3 Angiographic Findings DSA Gold standard for diagnosis and intervention Focal, segmental, eccentric, or concentric stenoses Ostial lesion: Proximal 2 cm of renal artery Poststenotic dilatation Collateral vessels > 50% RSA corresponds to ˜ 20 mm Hg gradient between renal artery and aorta Option for transcatheter intervention CO2 angiography in patients with renal failure Renal vein sampling can be performed at same time Infrequently used technique Increased renin production on side of stenosis Imaging Recommendations Best imaging tool Angiography: Gold standard; used for endovascular treatment CTA with MIP, volume rendering, reformatting Limited in patient with renal insufficiency Noncontrast MRA: Helpful in patients with renal dysfunction Protocol advice Imaging after appropriate history and physical exam, high index of suspicion MR: Multiplanar, 3D C+, dark blood, 2D time-of- flight, phase-contrast sequences Include adrenal glands to exclude adrenal pathology as etiology for hypertension Color Doppler US (3.5 MHz curvilinear probe) Requires accurate Doppler angle of ≤ 60° CECT/MR: Confirms findings on multiple images DIFFERENTIAL DIAGNOSIS Arterial Dissection Aortic dissection extending into renal artery; posttraumatic or iatrogenic renal artery dissection False or occluded lumen and intimal flap Vasculitis Polyarteritis nodosa; Takayasu arteritis P.15:14

Thromboembolism Filling defects in main renal artery or branches Acute onset of symptoms Fibromuscular Dysplasia Classic “string of beads” appearance to renal artery 1167

Diagnostic Imaging Cardiovascular Acute onset of hypertension, typically in young female PATHOLOGY General Features Etiology Atherosclerosis (60-90%) Staging, Grading, & Classification ≥ 50% narrowing of renal artery diameter is thought to be hemodynamically significant Gross Pathologic & Surgical Features Eccentric plaque in ostium or proximal renal artery Mild RAS: Normal-sized kidney Moderate to severe RAS: Atrophic kidney Poststenotic dilatation of main renal artery; collaterals Microscopic Features Complex fibrous plaque with calcification, hemorrhage, cholesterol, and thrombus CLINICAL ISSUES Presentation Most common signs/symptoms Hypertension New onset or malignant Requires > 3 medications to control hypertension Acute worsening of previously controlled hypertension Progressive or acute renal impairment Mild stenoses may be asymptomatic Other signs/symptoms Stenotic renal artery with embolization causes acute occlusion Acute flank or abdominal pain Acute renal insufficiency or failure Fever, nausea, and vomiting Clinical profile Patients with peripheral vascular disease &/or coronary artery disease Risk factors: Hypertension, hyperlipidemia, smoking, diabetes mellitus Lab data Positive captopril challenge test Exaggerated increased plasma renin activity Demographics Age > 50 years Gender M>F Epidemiology Renovascular hypertension: Secondary to renal artery occlusive disease Accounts for 1-4% of patients with hypertension Most common cause of secondary hypertension Atherosclerotic disease Most common cause of RAS (65-70%) Uncommon cause of hypertension (5%) Natural History & Prognosis Stenosis progression in untreated patients (40-50%) Progression to thrombosis or occlusion Complications Severe hypertension: Chronic untreated hypertension results in nephrosclerosis Renal insufficiency or renal failure secondary to ischemic nephropathy Treatment Options, risks, complications Intervention may be indicated when ≥ 1 primary renal functions are affected Refractory blood pressure control Worsening or malignant hypertension Volume control may cause recurrent congestive heart failure &/or flash pulmonary edema Decreased glomerular filtration may cause progressive renal insufficiency or failure 1168

Diagnostic Imaging Cardiovascular Treatment of stenosis can result in resolution, improvement, or no change in hypertension If no change, diagnose hypertension as “essential” Mixed response with renal insufficiency/failure Intervention has somewhat controversial role due to varied results from various studies Atheroemboli to renal bed may occur Medical management ACE inhibitors, diuretic therapy, β-blockers Endovascular management Percutaneous transluminal angioplasty (PTA) is treatment of choice when intervention is indicated Minimally invasive; 80% success rate in nonostial lesions, 30% in ostial lesions Primary stent placement with ostial lesions Stents also used if suboptimal PTA result or complications Surgical management Anatomic or extraanatomic bypass: Extraanatomic more common because of decreased morbidity Endarterectomy: Technically challenging, high risk Surgical revascularization: 80-90% success rate Nephrectomy: Typically reserved for kidneys having < 10% of renal function DIAGNOSTIC CHECKLIST Consider Rule out other causes of RAS RAS with asymmetric renal size Image Interpretation Pearls Renal artery narrowing at ostium or within 2 cm of ostium is typical of atherosclerotic stenosis SELECTED REFERENCES 1. Aburahma AF et al: Critical analysis of renal duplex ultrasound parameters in detecting significant renal artery stenosis. J Vasc Surg. 56(4):1052-1060, 2012 2. Sidhu R et al: Imaging of renovascular disease. Semin Ultrasound CT MR. 30(4):271-88, 2009 P.15:15

Image Gallery

(Left) Coronal contrast-enhanced MRA shows focal eccentric narrowing of the left renal artery. Note that the plaque at the left renal ostium extends into the aorta. Similarly, there is a plaque at the right renal ostium without significant narrowing of the right renal artery. (Right) Coronal contrast-enhanced MRA of the abdominal aorta shows focal severe narrowing of the right renal artery at its ostium. Note the absence of the left renal artery from prior nephrectomy.

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(Left) AP angiography of the aorta with a pigtail catheter positioned at the level of the renal arteries shows a normal right renal artery . There is a severe stenosis of the proximal left renal artery due to an eccentric plaque. The patient presented with uncontrollable hypertension despite taking 3 antihypertensive medications. (Right) AP angiography of the aorta (same patient) following left renal artery angioplasty and stenting shows a widely patent left renal artery with no residual stenosis.

(Left) AP angiography of the aorta with a flush catheter positioned at the suprarenal aorta shows a focal high-grade stenosis of the right renal artery. Note patent left renal arteries. The patient presented with uncontrolled hypertension despite taking 3 medications. (Right) AP angiography of the aorta in the same patient following renal artery angioplasty and stenting shows a widely patent right renal artery. Note that the stent is also visualized.

Fibromuscular Dysplasia, Renal Key Facts Terminology Fibromuscular dysplasia (FMD): Noninflammatory, nonatherosclerotic arterial disorder Characterized by segmental areas of collagen deposition and smooth muscle overgrowth Classified based on involved layer of arterial wall Imaging Classically shows “string of beads” appearance on DSA, mainly involving mid to distal renal artery CTA slightly more accurate than MRA for screening MRA becoming more common screening modality Angiography is gold standard for diagnosis Top Differential Diagnoses 1170

Diagnostic Imaging Cardiovascular Atherosclerosis Arteritis or vasculitis Segmental arterial mediolysis Neurofibromatosis, Marfan syndrome, or Ehlers-Danlos syndrome type IV Standing waves Clinical Issues New-onset or refractory hypertension Few or no risk factors for atherosclerosis Most common in females, ages 15-50 years Treatment of choice is percutaneous transluminal angioplasty (PTA) Hypertension cured or improved in > 95% of cases Has excellent long-term results/durability Diagnostic Checklist Consider renal FMD in patient with new-onset or refractory hypertension (especially young female) Look for “string of beads” appearance to renal arteries Best demonstrated on DSA May also be apparent on CTA and MRA imaging

(Left) DSA of the abdominal aorta shows bilateral renal artery involvement with FMD. This noninflammatory arterial disorder affects women far more often than men and involves the renal arteries in the majority of cases. (Right) Right renal artery DSA shows the classic “string of beads” appearance that is described in FMD. This is caused by sequential stenoses and aneurysms and is typical of medial fibroplasia, the most common FMD subtype. A guidewire has been placed across the stenoses in preparation for angioplasty.

(Left) CTA was obtained to evaluate the renal arteries in a 35-year-old woman with refractory hypertension. A coronal 1171

Diagnostic Imaging Cardiovascular MIP shows a “beaded” appearance to a lower right renal arterial branch and the upper branch of the left renal artery. (Right) Coronal oblique MIP image from an abdominal CTA shows irregular, “beaded” appearance of the right renal artery consistent with FMD. CTA and MRA are used for screening but are less sensitive and less specific than angiography, the gold standard for diagnosis. P.15:17

TERMINOLOGY Definitions Fibromuscular dysplasia (FMD): Noninflammatory, nonatherosclerotic arterial disorder Characterized by segmental areas of collagen deposition and smooth muscle overgrowth Affects multiple arterial territories Renal artery: Most commonly involved Carotid artery: 2nd most commonly involved May cause stenosis, dissection, aneurysms Known cause of renovascular hypertension Classified based on involved layer of arterial wall Intimal fibroplasia (< 10%) Focal concentric or long-segment tubular stenosis Internal elastic lamina may be disrupted Medial fibroplasia (3 subtypes) Medial dysplasia (80%): Multiple stenoses and aneurysms involving mid to distal renal artery; causes classic “string of beads” appearance Perimedial fibroplasia (10-15%): May also cause “string of beads” appearance; beads have smaller diameter than parent vessel Medial hyperplasia (1-2%): Smooth stenosis Adventitial fibroplasia (< 1%) Similar appearance to intimal fibroplasia IMAGING General Features Best diagnostic clue “String of beads” appearance is most characteristic Dilated arterial segments (“beads”) often larger in diameter than parent vessel Typical of medial dysplasia Classically described on angiography May also be evident on CTA/MRA reformations Location Involves mid to distal renal arteries (60-75%) Can also affect accessory renal arteries Less commonly affects intrarenal branches Frequently bilateral (up to 60% of cases) CT Findings CECT Signs of renal artery stenosis Atrophic kidney(s) Delayed parenchymal enhancement CTA Multifocal stenoses and aneurysms (“string of beads”) Typically best seen on reformations Ring-like or long-segment tubular stenosis may be seen if FMD involves layers other than media MR Findings T1WI C+ Signs of renal artery stenosis Corticomedullary thinning Delayed parenchymal enhancement with delayed contrast excretion MRA Findings similar to those seen on CTA Ultrasonographic Findings Grayscale ultrasound 1172

Diagnostic Imaging Cardiovascular Signs of renal artery stenosis Corticomedullary thinning Asymmetric renal size “String of beads” or irregular vascular morphology inconsistently seen Color Doppler Turbulence &/or irregularity of renal vasculature Elevated vascular flow in renal arteries Intravascular ultrasound (IVUS) Eccentric ridges or spiral folds Elevated pressure gradients (> 20-25 mm Hg) along affected length of renal artery Angiographic Findings Considered gold standard for FMD diagnosis Can obtain pressure gradients across renal artery Medial fibroplasia subtype: Multifocal stenoses/aneurysms in mid to distal renal artery Causes “string of beads” appearance Eccentric ridges/spiral folds Intimal or adventitial subtypes: Focal, concentric, or long-segment tubular stenosis Other findings Renal artery dissection Renal artery occlusion Elevated pressure gradients across renal artery Nuclear Medicine Findings Tc-99m MAG-3 or Tc-99m DTPA captopril renography Positive if captopril administration results in Reduced glomerular filtration rate (eGFR) by > 40% Delayed isotope uptake &/or excretion Equivocal examination may occur due to Low baseline eGFR Bilateral renal artery involvement Imaging Recommendations Best imaging tool Angiography is gold standard for diagnosing FMD Can also treat stenoses at time of diagnosis Noninvasive imaging modalities Doppler US: Often first-line screening; needs to include color Doppler evaluation Best utilized in follow-up after angioplasty CTA with MIPs and 3D reformations Most common screening modality MRA with MIPs Becoming more common screening modality Limited ability to see distal renal vasculature If abnormal noninvasive imaging, proceed to DSA DIFFERENTIAL DIAGNOSIS Atherosclerosis, Extracranial Stenosis typically adjacent to/involves arterial ostium Patients usually older than those with FMD Evidence of atherosclerotic disease in other arteries Arteritis or Vasculitis Can be difficult to differentiate from FMD Particularly intimal subtype Does not typically cause “string of beads” appearance More likely than FMD to affect multiple vascular beds Acute-phase reactants elevated in vasculitides but not in FMD P.15:18

Segmental Arterial Mediolysis Nonatherosclerotic, noninflammatory arteriopathy Characterized by dissections, aneurysms, occlusions 1173

Diagnostic Imaging Cardiovascular Results from lysis and weakening of arterial media Similar angiographic appearance to FMD May be FMD variant Predilection for mesenteric over renal arteries Classic presentation of acute flank/abdominal pain from visceral ischemia/infarction/hemorrhage Patients are usually older than those with FMD Neurofibromatosis, Marfan Syndrome, or Ehlers-Danlos Syndrome Type IV Syndromes with known vascular abnormalities May sometimes mimic various FMD subtypes Reliable diagnosis depends on patient history Standing Waves Transient benign angiographic finding Very symmetrically spaced “string of beads” Appear more regular, less pronounced than FMD May be physiological vascular response to rapid contrast injection or artifact from flow-related disruption of contrast medium layering in vessels PATHOLOGY General Features Etiology Idiopathic disorder Associated with cigarette smoking, estrogen exposure Genetics 11% of patients have 1st-degree relative with FMD Associated abnormalities Ehlers-Danlos syndrome type IV, Marfan syndrome, Alport syndrome, pheochromocytoma, Takayasu arteritis Gross Pathologic & Surgical Features Dysplastic process involving arterial wall Segmental collagen deposition and smooth muscle overgrowth interspersed among areas of thinning Thinned/weakened areas susceptible to aneurysm formation or dissection Pathologic characterization based on affected arterial layer where lesion predominates Microscopic Features Intimal fibroplasia Collagen deposition in intima; may have fragmented/duplicated internal elastic lamina Medial fibroplasia Medial dysplasia Alternating areas of medial thinning/weakening with thickened medial ridges Perimedial fibroplasia Patchy collagen deposition in media-adventitia junction Intact external elastic lamina Medial hyperplasia Concentric smooth muscle hyperplasia No fibrotic changes Adventitial fibroplasia Dense collagen replaces loose adventitial tissue CLINICAL ISSUES Presentation Most common signs/symptoms Most patients are asymptomatic Common: New-onset or refractory hypertension in patient without substantial risk factors for atherosclerosis Rare: Acute abdominal pain from FMD-related complications (e.g., renal artery dissection) Demographics Age Most often presents at 15-50 years of age Can present at any age, including pediatric patients Gender Female predominance in all types of FMD Intimal fibroplasia is exception 1174

Diagnostic Imaging Cardiovascular Has equal or slightly higher male predominance Natural History & Prognosis Indolent, slowly progressive disorder Stenoses may worsen; occlusion rare End-organ damage from FMD-related hypertension more severe than from essential hypertension Treatment Percutaneous transluminal angioplasty (PTA) is treatment of choice for renal FMD Reduces pressure gradients across renal artery to control renovascular hypertension Hypertension cured or improved in > 95% of cases Especially in younger patients &/or those with shorter duration of hypertension Excellent long-term prognosis after successful PTA No indication for primary stenting in FMD unless Failure of PTA Complication from PTA, such as arterial dissection Surgical bypass used infrequently Reserved for complex disease, distal involvement Clinical follow-up and US surveillance imaging after PTA DIAGNOSTIC CHECKLIST Consider Renal FMD in patient with new-onset or refractory hypertension, especially if young female Image Interpretation Pearls Classic “string of beads” appearance on angiography SELECTED REFERENCES 1. Baumgartner I et al: Renovascular hypertension: screening and modern management. Eur Heart J. 32(13):1590-8, 2011 2. Olin JW et al: Diagnosis, management, and future developments of fibromuscular dysplasia. J Vasc Surg. 53(3):82636, 2011 3. Blondin D et al: Fibromuscular dysplasia in living renal donors: still a challenge to computed tomographic angiography. Eur J Radiol. 75(1):67-71, 2010 4. Liu PS et al: CT angiography of the renal circulation. Radiol Clin North Am. 48(2):347-65, viii-ix, 2010 5. Slovut DP et al: Fibromuscular dysplasia. N Engl J Med. 350(18):1862-71, 2004 P.15:19

Image Gallery

(Left) MRA shows alternating narrowing and dilatation in the mid right renal artery, a typical appearance for FMD. Although MRA is more commonly used to screen for FMD than before, it is still slightly less accurate than CTA, especially in the distal renal artery branches. (Right) Renal artery DSA via a cobra catheter confirms the “beaded” appearance seen on MRA. If abnormalities are suspected on screening studies, angiography is indicated for confirmation and potential treatment with angioplasty.

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(Left) Right renal artery DSA in a 40-year-old woman with poorly controlled hypertension shows FMD involving the mid to distal right main renal artery . (Right) DSA shows (A) a PTA balloon inserted via a guiding catheter in the right renal artery ostium. The balloon has been placed across the affected arterial segment and has been inflated. (B) Despite a persistent post-PTA beaded appearance to the artery, as seen on DSA, this treatment is effective in eliminating stenoses, with good long-term results.

(Left) FMD is classified based on the affected layer of the wall of the artery. Involvement of the arterial media is most common. This is further divided into medial dysplasia, perimedial fibroplasia, and medial hyperplasia. Graphic shows the 3 main FMD subtypes: (A) Intimal, (B) medial, and (C) adventitial. (Right) The intimal subtype of FMD accounts for < 10% of cases and is characterized by a focal, concentric, or long-segment tubular stenosis as seen in the right renal artery on this DSA aortogram.

Polyarteritis Nodosa Key Facts Terminology Systemic vasculitis causing necrotizing inflammation of small and medium-sized vessels, resulting in microaneurysms, occlusions, and strictures Imaging Multiple 1-5 mm peripheral aneurysms Occlusions Irregular stenoses Diffuse wall thickening of medium-sized arteries Top Differential Diagnoses 1176

Diagnostic Imaging Cardiovascular Microscopic polyangiitis Systemic lupus erythematosus Wegener granulomatosis Churg-Strauss syndrome Drug abuse Fibromuscular dysplasia Clinical Issues Subacute presentation with vague symptoms: Fever, weight loss, malaise, headache, myalgia Spectrum of disease from single organ involvement to polyvisceral failure Brain, eyes, pancreas, lungs, testicles, ureters, breasts, and ovaries are rarely involved ESR and C-reactive protein may correlate with disease activity Diagnostic Checklist Multiple aneurysms are seen in 50-60% of cases, often at artery bifurcations Catheter angiography is mainstay for detecting microaneurysms and arterial stenosis/ectasia affecting small vessels Rapid diagnosis is necessary due to progression to life-threatening complications

(Left) AP angiography of the right renal artery in a patient suspected of having polyarteritis nodosa shows multiple microaneurysms affecting distal small branches of the right renal artery. (Right) AP angiography (delayed phase) in the same patient shows small microaneurysms within the right kidney. The persistence of contrast material within the microaneurysms during delayed-phase arteriography differentiates them from vascular loops. Small vascular loops do not retain contrast during the delayed phase.

(Left) AP angiography of right renal artery demonstrates multiple small aneurysms affecting the distal small arteries. However, similar microaneurysms may be seen in other inflammatory vasculitides. (Right) DSA shows the 1177

Diagnostic Imaging Cardiovascular characteristic multiple microaneurysms . There are also areas within the kidney parenchyma with decreased perfusion consistent with infarcts . Infarcts may represent necrosis or thrombosis. Hemorrhage may occur if the aneurysms rupture. P.15:21

TERMINOLOGY Abbreviations Polyarteritis nodosa (PAN) Synonyms Kussmaul-Maier disease Definitions Systemic vasculitis causing necrotizing inflammation of small and medium-sized vessels, resulting in microaneurysms, occlusions, and strictures IMAGING General Features Best diagnostic clue Multiple 1-5 mm peripheral aneurysms Occlusions Irregular stenoses Diffuse wall thickening of medium-sized arteries Location Kidneys (70-80%) GI tract, peripheral nerves, and skin (50%) Skeletal muscles and mesentry (30%) Central nervous system (CNS) (10%) Heart, testicles, lung, and spleen are rarely involved CT Findings NECT Multiple, often < 1 cm, renal and hepatic aneurysms appear as low-attenuation structures Wedge-shaped infarcts may be seen in kidney CECT Thickening of walls of medium-sized arteries Multiple small renal infarcts Consistent with fibrinoid necrosis and vascular thrombosis Perirenal and retroperitoneal hemorrhage from aneurysm rupture Infarcted bowel may appear thickened, perforated, or obstructed from stricture CTA Multiple aneurysms of varying sizes affecting renal, hepatic, or mesenteric arteries Smooth segmental narrowing of vessels Stenosis and occlusions of larger vessels Thickening of walls of medium-sized arteries MR Findings MRA Multiple aneurysms of varying sizes Demonstrates organ involvement with regions of ischemia or infarction Useful in suggesting diagnosis and monitoring disease progression and response to therapy Ultrasonographic Findings Color Doppler Operator dependent Aneurysms appear as small hyperechoic structures Often too small to detect with color flow Spectral analysis may demonstrate arterial stenosis Angiographic Findings Conventional angiography Multiple microaneurysms Aneurysms may be small, difficult to detect, or isolated to 1 organ Aneurysms may resolve in disease remission Should be differentiated from vascular loops 1178

Diagnostic Imaging Cardiovascular Arterial stenosis, ectasia Arterial thrombosis, occlusion Findings are predominately in visceral arteries Extremities and small branches of aorta are rarely involved Helps confirm clinical impression when biopsy is lacking or results are inconclusive Imaging Recommendations Best imaging tool Angiography is considered traditional gold standard CT and MR are less invasive and provide evidence of end-organ damage, arterial wall thickening, and arterial occlusions DIFFERENTIAL DIAGNOSIS Microscopic Polyangiitis Systemic vasculitis with clinical features similar to those of PAN Histologically similar to PAN except for involvement of smaller vessels Results in glomerulonephritis, which is not seen in PAN Imaging often does not reveal microaneurysms Systemic Lupus Erythematosus Small-vessel inflammation associated with antigen-antibody complexes Angiographic appearance similar to that of PAN with multiple microaneurysms Vessels show tapered or abrupt occlusions with few collateral vessels CT demonstrates dilated bowel, bowel wall thickening, ascites, lymphadenopathy, and hydronephrosis Wegener Granulomatosis Granulomatous vasculitis of upper &/or lower respiratory tracts with glomerulonephritis Multiple microaneurysms on imaging Often antineutrophil cytoplasmic antibody (ANCA) positive Churg-Strauss Syndrome Granulomatous vasculitis of multiple organ systems Multiple microaneurysms on imaging Often ANCA positive Drug Abuse May manifest as multiple microaneurysms in various organs Often severe renal, gastrointestinal, cardiac, and neurologic involvement Fibromuscular Dysplasia Angiography may demonstrate multiple aneurysms “String of beads” appearance Acute-phase reactants are normal In PAN, they are often elevated P.15:22

PATHOLOGY General Features Etiology Unknown; possibly associated with immune-complex deposition Often associated with hepatitis B virus (HBV) Occasionally, cases with HIV, CMV, human T-lymphotropic virus I, and hepatitis C virus are also reported Diagnosis is made by tissue biopsy in association with angiography Gross Pathologic & Surgical Features Aneurysms typically seen at vessel branch points Complete occlusion may occur secondary to endothelial proliferation and thrombosis Microscopic Features Necrotizing arteritis with pleomorphic cellular infiltrate in vessel walls Destruction of external and internal elastic laminae with fibrinoid necrosis of media CLINICAL ISSUES Presentation Most common signs/symptoms Subacute presentation with vague symptoms: Fever, weight loss, malaise, headache, myalgia Spectrum of disease from single organ involvement to polyvisceral failure Renal 1179

Diagnostic Imaging Cardiovascular Hypertension, renal insufficiency, vascular nephropathy (HTN, oliguric renal failure), hemorrhage May present with spontaneous subcapsular and perirenal hemorrhage (Wunderlich syndrome): Acute flank pain, flank mass, and hypovolemic shock Gastrointestinal Ischemia, abdominal pain, weight loss, infarction, bowel perforation, hemorrhage, pancreatitis, appendicitis, and cholecystitis Peripheral neuropathy Mononeuritis multiplex, often asymmetric neuropathy with sciatic involvement Cardiac Coronary arteritis, congestive heart failure Skin Palpable purpura, infarctions, and ulcerations Eye Retinal vasculitis, retinal detachment, cottonwool spots Brain, eyes, pancreas, lungs, testicles, ureters, breasts, and ovaries are rarely involved Clinical profile Clinical symptoms related to ischemia Arthralgia and peripheral neuropathies are often symptomatic early No association with ANCA ESR and C-reactive protein may correlate with disease activity Demographics Age Most common in 5th-7th decades Gender M:F = 2:1 Epidemiology Annual incidence: 2-9 cases per million Up to 77 per million in areas hyperendemic for HBV Natural History & Prognosis Fulminant disease, 5-year survival rate < 15% Relapse in 40% of patients; median survival 33 months 50% of patients with abdominal involvement develop acute surgical abdomen with mortality rate of 12.5% 5-factor score estimates prognosis Scores renal, GI, cardiac, and CNS involvement Low score correlates with higher 5-year survival rate Treatment Glucocorticoids as first-line treatment Remission in 50% of patients Addition of cyclophosphamide Remission or cure in 90% of patients HBV-associated PAN requires addition of antivirals Plasma exchange/plasmapheresis may have added benefit in refractory cases Large aneurysms may be treated by catheter embolization to avoid risk of rupture Surgery may be needed to treat GI complications DIAGNOSTIC CHECKLIST Consider Rapid diagnosis necessary due to progression to life-threatening complications CNS hemorrhage, GI hemorrhage or perforation, acute appendicitis, liver infarct, acute renal failure, renal/perirenal hematomas, and cardiac failure Image Interpretation Pearls Multiple aneurysms are seen in 50-60% of cases, often at artery bifurcations Catheter angiography is mainstay for detecting microaneurysms and arterial stenosis/ectasia affecting small vessels SELECTED REFERENCES 1. Higuchi T et al: The usefulness of 3D-CT angiography in polyarteritis nodosa. Intern Med. 51(11):1449-50, 2012 2. Katabathina VS et al: Wunderlich syndrome: cross-sectional imaging review. J Comput Assist Tomogr. 35(4):425-33, 2011

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Diagnostic Imaging Cardiovascular 3. Mavrogeni S et al: Detection of coronary artery lesions and myocardial necrosis by magnetic resonance in systemic necrotizing vasculitides. Arthritis Rheum. 61(8):1121-9, 2009 4. Ozaki K et al: Renal involvement of polyarteritis nodosa: CT and MR findings. Abdom Imaging. 34(2):265-70, 2009 5. Tsai WL et al: Polyarteritis nodosa: MDCT as a “one-stop shop” modality for whole-body arterial evaluation. Cardiovasc Intervent Radiol. 31 Suppl 2:S26-9, 2008 6. Ozcakar ZB et al: Polyarteritis nodosa: successful diagnostic imaging utilizing pulsed and color Doppler ultrasonography and computed tomography angiography. Eur J Pediatr. 165(2):120-3, 2006 P.15:23

Image Gallery

(Left) AP angiography of right renal artery shows multiple peripheral wedge-shaped filling defects in the kidney, consistent microinfarcts. These are secondary to microthrombi or occlusion of small arteries from arterial inflammation. (Right) AP angiography of the left renal artery in the same patient shows wedge-shaped peripheral filling defects during nephrogram, consistent with small infarcts. These are secondary to vascular occlusions from arterial thrombi or inflammation.

(Left) Coronal CECT of the superior mesenteric artery shows an irregularity of the artery with perivascular soft tissue thickening from inflammation. Note that the inflammatory thickening extends to smaller branches distally. (Right) Sagittal CTA in the same patient again shows diffuse perivascular thickening of the superior mesenteric artery, consistent with inflammatory vasculitis. Vascular thickening is nonspecific and can be seen in a myriad of inflammatory vasculitis cases.

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(Left) AP angiography of celiac artery shows multiple small microaneurysms of the hepatic arterial branches. In addition, there are multiple areas of vessel narrowing and dilatation . These features are consistent with polyarteritis nodosa. (Right) Axial CECT of the abdomen shows an aneurysm of a medium-sized right renal artery branch in a patient with a known diagnosis of polyarteritis nodosa. Polyarteritis nodosa affects both small and medium-sized arteries.

Renal Arteriovenous Fistula Key Facts Terminology Renal arteriovenous fistula (AVF): Abnormal direct communication between a renal artery and vein Imaging Best diagnostic clue Simultaneous opacification of artery and vein during arterial phase of CECT or DSA Pseudoaneurysm at site of AV communication Ultrasound findings May show arterial-to-venous branch communication When AVF is identified, draining vein may show arterialized flow pattern Pathology Renal AVFs are almost always acquired Penetrating injuries (e.g., gunshot or stab wounds) may result in renal AVF Iatrogenic trauma is common cause of renal AVF Clinical Issues Majority of renal AVFs are asymptomatic May have hematuria, hypertension, &/or flank pain when symptomatic Occasionally may have high-output cardiac failure, bruit, or spontaneous retroperitoneal hemorrhage Percutaneous transcatheter embolization is preferred treatment for symptomatic lesions Embolization should be as selective as possible, with catheter positioned close to fistula Goal is successfully closing AVF while minimizing loss of normal renal parenchyma Transcatheter embolization has 80-100% success rate Nontarget embolization and large infarcts are greatest concerns Small infarcts are usually asymptomatic 10% incidence of postembolization syndrome: Transient pain, leukocytosis, and fever

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(Left) Color Doppler US of the upper renal pole in a man who developed hematuria and flank pain after a percutaneous right renal biopsy shows (A) heterogeneous signal and an arterial waveform in a round vascular mass . (B) Arterial signal is also seen in the vein draining the vascular mass. Findings are consistent with an iatrogenic renal pseudoaneurysm and AVF. (Right) Renal DSA shows an early draining vein in the arterial phase of the study, with a pseudoaneurysm at the site of arteriovenous communication.

(Left) Superselective DSA of (C) segmental renal artery shows the pseudoaneurysm and also the intrarenal arterial branch from which the AVF arises. (D) A microcatheter has been used to occlude the feeding branch with embolization coils . The draining vein is still opacified as the arterial feeder has not yet thrombosed. (Right) Right renal DSA after coil embolization shows that the draining vein and pseudoaneurysm no longer opacify, consistent with successful transcatheter treatment. P.15:25

TERMINOLOGY Definitions Renal arteriovenous fistula (AVF): Abnormal direct communication between a renal artery and vein IMAGING General Features Best diagnostic clue Simultaneous opacification of artery and vein during arterial phase of CECT or DSA Intraparenchymal pseudoaneurysm connecting arterial and venous branches Location Typically intraparenchymal 1183

Diagnostic Imaging Cardiovascular Less frequently extraparenchymal Size Variable; depends on size and location of arterial and venous branches involved in fistulous communication Imaging Recommendations Best imaging tool CECT with CTA; DSA Ultrasonographic Findings Color Doppler May show direct arterial-to-venous branch communication When AVF is identified, draining vein may show arterialized flow pattern May demonstrate any pseudoaneurysm and relationship to AVF Pseudoaneurysm appears as anechoic mass with internal color flow CT Findings CECT Simultaneous opacification of artery and vein during arterial phase imaging Pseudoaneurysm may be present at site of arteriovenous communication Extravascular contrast collection; delayed clearing May show intraparenchymal hematoma or infarct from post-traumatic AVF May be useful following transcatheter embolization to assess for parenchymal infarcts CTA Will have similar findings to catheter angiography Angiographic Findings Simultaneous opacification of artery and vein during arterial phase of DSA May show early draining vein Pseudoaneurysm may be present at site of arteriovenous communication Intrarenal hematoma with vessel displacement or splaying may be present Angiography is used for imaging guidance during transcatheter treatment of AVF MR Findings MRA Will have similar findings to angiography and CTA Infrequently used in evaluation, treatment planning, or follow-up of AVF DIFFERENTIAL DIAGNOSIS Renal Arteriovenous Malformation Congenital abnormal communications between intrarenal arterial and venous systems Typically has central vascular nidus Congenital renal arteriovenous malformation (AVM) is rare (0.004% incidence) Congenital cirsoid AVMs have dilated, corkscrew appearance, much like varicose veins Multiple communications between arteries & veins Communications develop multiple coiled channels Form vascular mass within renal parenchyma Arterial supply arises from ≥ 1 segmental or interlobar renal arteries Proximity to collecting system may explain high prevalence of hematuria Cavernous AVMs have single dilated vessels Much less common than cirsoid AVM Single artery feeds into single cystic chamber, with single draining vein Symptomatic patients present with hematuria, hypertension, and flank pain Gross hematuria is initial symptom in 75%, hypertension in 25% Less common symptoms include high-output cardiac failure and spontaneous retroperitoneal hemorrhage Lesions are typically visible on CT and MR; need DSA for confirmation and potential transcatheter treatment Preferred treatment is transcatheter embolization Extremely large AVMs may require surgical resection Renal Neoplasm Most are typically asymptomatic May have symptoms of hematuria &/or flank pain Renal cell carcinoma can be highly vascular May have significant arteriovenous shunting Very rarely can have sufficient arteriovenous shunting to produce high-output cardiac failure 1184

Diagnostic Imaging Cardiovascular Angiogenic tumor factors have been implicated in development of AVMs within renal neoplasms Usually treated with surgical resection Percutaneous ablation is appropriate for smaller tumors Renal Artery Aneurysm Rare lesions with incidence of ˜ 0.1% 20% bilateral and 30% multiple Occur equally in men and women Aneurysms from atherosclerosis, fibromuscular dysplasia, and segmental arterial mediolysis typically involve extraparenchymal renal artery branches Extraparenchymal aneurysms predominate (˜ 85%) 70% saccular, 20% fusiform, and 10% dissecting Aneurysms associated with vasculitis (polyarteritis nodosa) or with hematogenous infection are typically intraparenchymal and located peripherally Commonly are microaneurysms Typically asymptomatic Symptomatic patients may have hematuria, hypertension, and flank pain Incidence of hypertension may be as high as 90% Symptomatic or ruptured aneurysms may be treated surgically or endovascularly Rupture more common in females during pregnancy P.15:26

Nutcracker Syndrome Compression of left renal vein between aorta and superior mesenteric artery causes left renal venous hypertension and hematuria Left renal venous hypertension causes intrarenal and perirenal varices Varices may rupture into renal collecting system Results in hematuria May also have abdominal, flank, and pelvic pain Conservative management if mild symptoms Treatment indicated for recurrent/massive hematuria Surgical and endovascular treatments have been used Surgical options: Left renal vein reanastomosis to inferior vena cava (IVC), autotransplantation of left kidney, and nephrectomy Endovascular options: Percutaneous transluminal angioplasty (PTA) and intravascular stent placement PTA is usually ineffective; stent is typically required Currently no consensus on indication for and success of endovascular treatment PATHOLOGY General Features Etiology Renal AVFs are almost always acquired Penetrating injuries such as gunshot and stab wounds may result in renal AVFs Iatrogenic trauma is common cause of renal AVF Occurs in 15% of percutaneous renal biopsies Percutaneous nephrostomy & tract dilatation for percutaneous nephrostolithotomy are also causes Incidence in renal allografts ranges (0.2-2%) Needle biopsy is often necessary to evaluate for suspected rejection/reduced renal function Idiopathic renal AVFs are uncommon Have characteristics of acquired AVF However, no identifiable etiology May arise from spontaneous erosion or rupture of diseased renal arterial segment into adjacent vein CLINICAL ISSUES Presentation Most common signs/symptoms Majority are asymptomatic 1185

Diagnostic Imaging Cardiovascular Hematuria, hypertension, &/or flank pain when symptomatic Other signs/symptoms Less commonly, may have high-output cardiac failure, bruit, or spontaneous retroperitoneal hemorrhage Demographics Epidemiology Renal AVFs may be present in 1/3 of patients with hypertension occurring after renal trauma Occur frequently after penetrating flank trauma Natural History & Prognosis Many post-traumatic renal AVFs may close spontaneously, particularly if small New onset of hypertension may be seen in larger AVFs Large AVFs usually require corrective treatment Treatment Most conservative treatment possible is favored in management of renal injuries such as AVF Percutaneous transcatheter embolization is preferred treatment for symptomatic lesions Must determine whether vessel(s) can be sacrificed Occlusion of renal branch(es) causes infarction proportional to vessel size and vascular territory Embolization should be as selective as possible, with catheter positioned close to fistula Goal is successful closure of AVF while minimizing loss of normal renal parenchyma Gelatin sponge (Gelfoam), coils, and plug occluders are most commonly used embolic agents AVFs between main renal artery and vein have been treated with covered stents Transcatheter embolization has 80-100% success rate Low complication rate Nontarget embolization and large infarcts are greatest concerns Small infarcts are usually asymptomatic Transient hypertension occasionally occurs 10% incidence of postembolization syndrome: Transient pain, leukocytosis, and fever Nephrectomy was past treatment for large AVFs Variety of newer embolic agents allows endovascular treatment of even very large renal AVFs e.g., Amplatzer plug occluders, covered stents DIAGNOSTIC CHECKLIST Consider Renal AVF in patient with new hypertension or hematuria following renal intervention or trauma Image Interpretation Pearls Look for simultaneous arterial and venous opacification during arterial phase of CECT or DSA Pseudoaneurysm may be present at site of arteriovenous communication SELECTED REFERENCES 1. Lorenzen J et al: Post-biopsy arteriovenous fistula in transplant kidney: treatment with superselective transcatheter embolisation. Eur J Radiol. 81(5):e721-6, 2012 2. Kensella D et al: Transcatheter embolization of a renal arteriovenous fistula complicated by an aneurysm of the feeding renal artery. Cardiovasc Intervent Radiol. 31(2):415-7, 2008 3. Idowu O et al: Dual use of an amplatzer device in the transcatheter embolization of a large high-flow renal arteriovenous fistula. J Vasc Interv Radiol. 18(5):671-6, 2007 4. Park BK et al: Arteriovenous fistula after radiofrequency ablation of a renal tumor located within the renal sinus. J Vasc Interv Radiol. 18(9):1183-5, 2007 5. Tam J et al: Acute traumatic renal artery to inferior vena cava fistula treated with a covered stent. Cardiovasc Intervent Radiol. 29(6):1129-31, 2006 6. Garcia-Schurmann JM et al: Spontaneous thrombosis of an iatrogenic arteriovenous fistula of the kidney. Urology. 58(1):106, 2001 7. Reilly KJ et al: Angiographic embolization of a penetrating traumatic renal arteriovenous fistula. J Trauma. 41(4):763-5, 1996 8. Corr P et al: Embolization in traumatic intrarenal vascular injuries. Clin Radiol. 43(4):262-4, 1991 P.15:27

Image Gallery

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(Left) Percutaneous interventions such as renal biopsy or nephrostomy tube placement can result in iatrogenic renal AVFs. (A) Native and (B) DSA renal arteriography images show a nephrostomy tube and ureteral stent .A segmental left renal artery & vein are simultaneously opacified during the arterial phase of the DSA, consistent with renal AVF. (Right) Unsubtracted left renal artery DSA shows that the AVF was treated by placing embolization coils in the arterial branch feeding the fistula.

(Left) The arteriovenous shunting of an AVM can mimic an AVF. Coronal reconstruction from the arterial phase of a CTA shows a vascular mass in the renal parenchyma. A segmental branch from the main renal artery supplies the mass. There is an accessory lower pole renal artery . (Right) Axial CT reconstruction shows that the vascular mass is lobulated and is the point of communication between the feeding artery and draining vein . The mass represents the AVM nidus.

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(Left) DSA shows that the lobulated nidus of the AVM is densely opacified. There is brisk filling of the right renal vein and IVC in the arterial phase of the DSA, confirming a high-flow malformation. Sometimes there is associated high-output cardiac failure. The lower renal pole is unopacified as it is supplied by an accessory renal artery. (Right) Post-treatment DSA shows that the artery feeding the AVM has been occluded with embolization coils , and both the nidus and the draining vein no longer fill.

Renal Vein Thrombosis Key Facts Terminology Thrombotic renal vein obstruction or occlusion Imaging Filling defect in renal vein, renal enlargement, delayed function Low-attenuation filling defect within renal vein Persistent parenchymal opacification Thickening of Gerota fascia and perinephric “whiskering” (edema or hemorrhage) Absent flow in renal vein in acute complete occlusion on Color Doppler Multiple enlarged venous collaterals in chronic thrombosis Top Differential Diagnoses Renal vein tumor extension Pyelonephritis Retroperitoneal processes Gonadal vein thrombosis Nutcracker syndrome Clinical Issues Sequelae of renal vein thrombosis depends on duration of occlusion, recanalization, and collateralization Primary medical therapy is anticoagulation Systemic thrombolytic therapy may be considered in severe cases Suprarenal inferior vena cava filter placement if thrombus extends into inferior vena cava Catheter-directed thrombolysis can be used primarily or to “clean up” residual thrombus after mechanical thrombectomy Surgical therapy with thrombectomy or nephrectomy if other management fails

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(Left) Axial CECT shows filling defect within the left renal vein consistent with partial thrombosis. There is still minimal flow around the thrombus. The left kidney is mildly enlarged. (Right) Axial delayed-phase CECT in an another patient shows nonenhancing thrombus within the left renal vein. Note associated enlargement of the left kidney with perinephric stranding . These features are consistent with acute renal vein thrombosis.

(Left) Axial CECT shows enhancing thrombus within the left renal vein suggesting the presence of tumor thrombus. Note the tumor in the posterior half of the left kidney. (Right) Coronal CECT in the same patient shows a tumor thrombus within the left renal vein that extends into the suprarenal inferior vena cava . Note the enhancement of the tumor. Also note the nonenhancing bland thrombus within the infrarenal inferior vena cava that developed secondary to venous stasis. P.15:29

TERMINOLOGY Abbreviations Renal vein thrombosis (RVT) Synonyms Renal vein occlusion Definitions Thrombotic renal vein obstruction or occlusion IMAGING General Features Best diagnostic clue Filling defect in renal vein, renal enlargement, delayed function 1189

Diagnostic Imaging Cardiovascular Location Unilateral > bilateral (more common in children) Left renal vein > right renal vein Thrombus extension to inferior vena cava (IVC), sometimes to right atrium Size Renal enlargement (75% of cases) Renal vein enlargement with acute thrombosis Small shrunken kidney with chronic thrombosis Morphology Acute or chronic (more common) thrombosis Partial or complete venous obstruction CT Findings CECT Low-attenuation filling defect within renal vein Decreased nephrographic attenuation Persistent parenchymal opacification No corticomedullary differentiation Delayed excretion into renal calyces and pelvis Enlarged (acute) or shrunken (chronic) renal vein Thickening of Gerota fascia and perinephric “whiskering” (edema or hemorrhage) Opacified periureteral and perinephric (“cobwebs”) venous collaterals CTA Tortuous and dilated collateral veins near ureters Retrograde flow in dilated superficial veins if there is associated IVC occlusion Ultrasonographic Findings Grayscale ultrasound Acute: Renal enlargement from venous congestion and edema Renal vein distended by faintly echogenic thrombus Hypoechoic kidney; loss of corticomedullary differentiation Heterogeneous kidney; areas of necrosis, hemorrhage Echogenic thrombosed parenchymal veins radiating from hilum Subacute: Improved corticomedullary differentiation; increased cortical echogenicity ↑ echogenicity of thrombus; ↓ size of renal vein Chronic: Varies with degree of renal injury Normal appearance ↑ corticomedullary differentiation Small, shrunken kidney with scarring Echogenic thrombus with small, scarred renal vein Thrombus or tumor in IVC (≤ 20%) Color Doppler Absent flow in renal vein in acute complete occlusion Renal vein filling defect in acute incomplete occlusion “Tram track” sign of flow around thrombus ↑ flow velocity and turbulence Chronic occlusion can recanalize Multiple collateral veins if minimal or no recanalization Absent duplex venous signal Renal artery and proximal branches Narrow, sharp systolic peaks from increased pulsatility Continuous retrograde flow during diastole MR Findings MRA Contrast enhanced to delineate thrombus T1WI, T2WI Filling defect in renal vein Prolongation of renal cortex and medulla relaxation times, resulting in low signal intensity Poor corticomedullary differentiation ↑ signal intensity of renal veins (loss of flow void) Multiple perinephric collateral veins 1190

Diagnostic Imaging Cardiovascular Angiographic Findings Renal arteriogram with imaging into venous phase Filling defect in main renal vein Possible extension into IVC Nonvisualized main renal vein Multiple enlarged venous collaterals Renal venography Intraluminal filling defect or venous occlusion Venous collaterals if chronic Radiographic Findings IVP Delayed, hyperdense, or prolonged nephrogram (partial obstruction) Little or no nephrographic opacification (complete) Poorly opacified renal collecting system Notching of renal pelvis and ureter by collaterals Enlarged or small kidney, depending on chronicity Nuclear Medicine Findings Delayed or absent renal perfusion Accumulation of radiotracer mimics accumulation of contrast Imaging Recommendations Best imaging tool US followed by CECT or C+ MR Protocol advice CTA: Corticomedullary phase best; delayed-phase acquisition performed at 90-120 seconds DIFFERENTIAL DIAGNOSIS Renal Vein Tumor Extension Large renal mass; usually renal cell carcinoma Vascular, enhancing tumor thrombus P.15:30

Pyelonephritis Kidney has appearance of renal vein thrombosis, but with patent renal vein Differentiate by clinical history and urinalysis Retroperitoneal Processes Lymphoma, other neoplasm, retroperitoneal fibrosis Process narrows, encases, or displaces renal vein Gonadal Vein Thrombosis Usually bland thrombus; may extend into renal vein Nutcracker Syndrome Compression of left renal vein as it crosses between aorta and superior mesenteric artery May cause left renal venous hypertension, hematuria May have extensive venous collaterals PATHOLOGY General Features Etiology Primary renal disease Nephrotic syndrome, typically membranous glomerulonephritis Pyelonephritis Renal hypoperfusion by hypovolemia or vascular stasis (dehydration, sepsis, hemorrhage) Hypercoagulable states (pregnancy) Mechanical compression (tumor, nutcracker syndrome) Genetics Inherited hypercoagulable states (protein S, protein C deficiency) Associated with nephrotic syndrome in adults Associated with dehydration and sepsis in children Gross Pathologic & Surgical Features Acute: Congested and edematous kidney Total occlusion leads to hemorrhagic infarction followed by necrosis and fibrosis 1191

Diagnostic Imaging Cardiovascular Chronic: Small, scarred kidney Fibrosis leads to renal atrophy Microscopic Features Acute: Edema, hemorrhage, infarction Subacute: Necrosis Chronic: Fibrosis, scarring, dystrophic calcification CLINICAL ISSUES Presentation Most common signs/symptoms Acute (more common in infants & children < 2 years) Flank pain, nausea, vomiting Palpable kidney, hypertension Hematuria, proteinuria if renal function persists Acute renal failure Chronic Asymptomatic Renal failure Hypertension Other signs/symptoms Thromboembolic disease, particularly pulmonary embolus Demographics Age Adults or < 2 years of age Incidence Unknown in asymptomatic patients Nephrotic syndrome: 16-42% of patients Natural History & Prognosis Sequelae of renal vein thrombosis depends on duration of occlusion, recanalization, and collateralization Complications Recurrent thromboemboli, particularly to pulmonary circulation Renal failure Renal hemorrhage Good prognosis; frequent spontaneous recovery Treatment Primary medical therapy is anticoagulation Intravenous heparin, then oral warfarin Low molecular weight heparin Systemic thrombolytic administration Consider with: Bilateral renal vein thrombosis, IVC extension, massive clot burden, pulmonary emboli, severe flank pain, or failed anticoagulation Endovascular therapy Suprarenal IVC filter placement if thrombus extends into IVC Recurrent pulmonary embolism or thromboembolic disease Risk of embolization during mechanical thrombectomy Mechanical thrombectomy improves renal vein outflow rapidly Catheter-directed thrombolysis can be used primarily to “clean up” residual thrombus after mechanical thrombectomy Following endovascular therapy, patient is chronically anticoagulated Surgical therapy with thrombectomy or nephrectomy if other management fails DIAGNOSTIC CHECKLIST Consider Clinical suspicion, rapid diagnosis, and early intervention allow preservation of renal function Rapid return of venous outflow yields decreased serum creatinine; increased glomerular filtration rate (GFR) Image Interpretation Pearls Look for filling defect in renal vein and multiple venous collaterals SELECTED REFERENCES 1. Kim HS et al: Catheter-directed thrombectomy and thrombolysis for acute renal vein thrombosis. J Vasc Interv Radiol. 17(5):815-22, 2006 2. Kawashima A et al: CT evaluation of renovascular disease. Radiographics. 20(5):1321-40, 2000 1192

Diagnostic Imaging Cardiovascular 3. Tempany CM et al: MRI of the renal veins: assessment of nonneoplastic venous thrombosis. J Comput Assist Tomogr. 16(6):929-34, 1992 4. Jeffrey RB et al: CT and ultrasonography of acute renal abnormalities. Radiol Clin North Am. 21(3):515-25, 1983 P.15:31

Image Gallery

(Left) Axial T2* GRE MR shows high intraluminal signal within the left renal vein from tumor thrombus. The left kidney is enlarged. (Right) Axial T1WI C+ FS MR in the same patient shows filling defect within the left renal vein consistent with thrombus. Note small bright arterial channels within the thrombus suggesting that the thrombus is a tumor thrombus. Note the tumor in the kidney. This was a renal cell carcinoma on biopsy.

(Left) PA renal scan shows absence of perfusion to the left kidney following renal vein thrombosis. Note normal perfusion of the right kidney . (Right) Coronal CECT shows a tumor (hepatocellular carcinoma) extending in to the IVC and portal vein . Occlusion of the suprarenal IVC from tumor thrombus resulted in venous stasis and retrograde bland thrombosis of the infrarenal IVC and left renal vein .

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(Left) Delayed-phase image from right renal arteriography shows absence of right renal vein. There are multiple perirenal collateral veins around the hilum that connect to the phrenic veins , which drain into the IVC. (Right) In the same patient, left renal arteriogram shows absence of left renal vein and multiple collaterals around the renal hilum. The flow is routing through the left gonadal vein, inferior mesenteric vein, and portal vein due to gonadomesenteric venous collateralization.

Section 16 - Peripheral Vasculature Introduction and Overview Approach to Peripheral Vasculature > Table of Contents > Section 16 - Peripheral Vasculature > Introduction and Overview > Approach to Peripheral Vasculature Approach to Peripheral Vasculature Suvranu Ganguli, MD Introduction The vasculature within the periphery of the body, including the upper extremities, the lower extremities, and the pelvis, can be affected by a variety of vascular disorders. The most common pathologic entity involving vessels of the periphery is atherosclerosis, which leads to stenoses, aneurysms, and occlusions. However, other clinically relevant conditions, such as vasculitis, trauma, compression syndromes, and thromboembolism, are also seen in the periphery. Pathologic Issues Peripheral Arterial Disease While the term “peripheral vascular disease” can apply to both venous and arterial diseases, most commonly it refers to peripheral arterial disease (PAD), typically involving the lower extremities. PAD is clinically important for two major reasons: (1) It may produce symptoms ranging from minor claudication to ulceration, gangrene, and potential limb loss; and (2) PAD is a marker for atherosclerosis in other arterial distributions, such as the coronaries and carotids. PAD is a relatively common condition that affects many adults worldwide. PAD remains underrecognized, and the impact of this disorder on quality of life is not appreciated by many health care providers. PAD starts early in life for many individuals and remains asymptomatic for a long time. Risk factors for PAD include older age, cigarette smoking, diabetes, dyslipidemia, and hypertension. It often has clinical symptoms only when it is relatively advanced. The most common symptom is intermittent claudication, a cramping pain in the legs that is induced by exercise and relieved by rest. When PAD progresses to severe impairment of blood flow to the limb due to arterial stenosis or occlusion, an individual is considered to have critical limb ischemia. Critical limb ischemia is often characterized by persistent rest pain, which becomes worse when the legs are elevated. People diagnosed with critical limb ischemia may also present with gangrene and ulceration in their legs. Common locations of steno-occlusive disease are the superficial femoral artery at the Hunter canal, common iliac artery, mid popliteal artery, tibioperoneal trunk, and origins of the tibial artery. These sites reflect the areas of maximum shear stress on the arterial wall. 1194

Diagnostic Imaging Cardiovascular In the upper extremities, atherosclerosis is less common but still present. Asymptomatic disease is often discovered when asymmetrical arm blood pressures are found during clinical examination. Symptoms include arm pain with exertion, rest pain, and digit ulceration. Coldness, nail and skin atrophy, and hair loss can be indicative of long-term ischemic changes, similar to changes in the lower extremities. Patients with proximal subclavian artery stenosis may have symptoms of subclavian steal syndrome: Dizziness, vertigo, and syncope during arm exertion. The treatment of PAD continues to evolve but is fundamentally focused on control of risk factors to prevent the associated risk of heart attack and stroke, improvement in exercise performance, and revascularization. Aneurysms Aneurysms of the peripheral arteries may result from trauma, infection, inflammatory vasculitis, and degenerative disease (such as atherosclerosis). Connective tissue disorders, such as Ehlers-Danlos syndrome and Marfan syndrome, may result in aneurysms in young patients. Degenerative aneurysms tend to affect multiple arteries, and assessing the aorta and femoropopliteal arteries is important when a degenerative aneurysm is found in any one of the arteries. Aneurysms of the peripheral arteries are usually treated if the aneurysm becomes symptomatic (thromboembolism, rupture, compression of adjacent veins resulting in deep vein thrombosis) or if the aneurysms grow to a size associated with high future rupture. The most common sites for peripheral arterial aneurysms include the popliteal artery, iliac artery, and common femoral artery. Thromboembolic Disease An acutely ischemic leg or arm is a surgical emergency given the risk of irreversible loss of limb after six hours of ischemia. Causes include embolization from cardiac disorders (e.g., left atrial or ventricular aneurysms, valvular vegetations) or proximal vessel disease (e.g., thromboembolism from a proximal disease artery) as well as in situ thrombosis of diseased native arteries and bypass grafts. Symptoms differ based on the presence of collateral vessels in the leg. Given the development of collateral pathways in chronic peripheral arterial disease, in situ thrombosis is usually better tolerated than embolic occlusion. The diagnosis of acute extremity ischemia is based on clinical findings, and imaging is not always performed to prevent delay in revascularization. Treatment involves systemic heparinization and revascularization through locoregional pharmacomechanical thrombolysis or surgical thrombectomy. Pathology-based Imaging Issues Noninvasive Physiologic Evaluation Noninvasive evaluation of upper and lower extremity arterial disease is important in assessing the physiologic impact of occlusive disease because symptoms and the severity of disease do not always correlate. Noninvasive physiologic evaluation provides objective means to assess the severity of disease and helps monitor disease progression and outcomes of therapies. Tests can be performed at rest or after standardized exercise or provocative maneuvers. Occlusive disease that is well compensated at rest may be unmasked on exercise testing. Physical examination is part of noninvasive evaluation of skin integrity, temperature, capillary refill, and palpable pulses. Ankle-brachial index (ABI) refers to the ratio of the highest upper arm pressure on either side to the highest ankle pressure obtained through Doppler evaluation of the dorsalis pedis and posterior tibial arteries. The ABI provides information about the presence and severity of PAD but does not supply information on the level of the occlusive process. An ABI ≥ 1.0 indicates the absence of PAD, and lower ABI usually correlates with the severity of disease. During exercise, the ABI remains normal or elevated in the absence of PAD, and it drops when there is occlusive inflow disease. The ABI may be falsely elevated in the presence of noncompressible arteries; in such cases, toe pressures should be obtained. Segmental limb pressures consist of obtaining blood pressure measurements at the thigh, calf, and ankles with appropriately sized blood pressure cuffs, or similarly in the arm in the upper extremity. A drop of 20-30 P.16:3 mm Hg pressure at any level or a difference > 20 mm Hg compared with the opposite side indicates hemodynamically significant occlusive disease in that vascular segment. The test is usually combined with Doppler evaluation of arterial inflow at each level. Doppler analysis of the arterial waveform provides information about the presence and severity of occlusive disease. The normal Doppler pattern of peripheral arteries is triphasic. In the presence of occlusive disease, the arterial waveform becomes monophasic with decreased amplitude. Pulse-volume recordings are obtained by applying appropriately sized blood pressure cuffs at various levels in the upper or lower extremities, inflating cuffs to 60-65 mm Hg pressure and recording the changes in the pressure of the cuff. The pressure changes within the cuff represent changes in the blood volume during systole and diastole. These waveforms are assessed for changes in amplitude and contour. Loss of the normal dicrotic notch and flattening of waveforms indicate the presence of PAD in that vascular segment. Color Doppler Ultrasound Color Doppler ultrasound allows evaluation of arteries and bypass grafts. Every arterial segment is evaluated with grayscale, color flow, and spectral Doppler imaging, with special emphasis on peak systolic velocity and Doppler waveforms. On spectral Doppler imaging, peripheral arteries demonstrate a triphasic flow pattern. At the site of

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Diagnostic Imaging Cardiovascular stenosis, the waveforms become monophasic or biphasic with increased peak systolic velocity; distal to a hemodynamically significant stenosis, the waveforms become monophasic with a tardus parvus pattern. Computed Tomography Angiography Computed tomography angiography (CTA) provides excellent soft tissue resolution and with current technology can provide catheter angiography-like images of the arterial tree. CTA is the go-to modality for cross-sectional assessment of aneurysms, stenoses, and vascular abnormalities throughout the vascular tree. Current multidetector scanners allow scanning of the entire abdomen and lower extremities in just a few seconds. However, such scanning can be a problem when assessing asymmetric aortoiliac disease and PAD. The scanner may outrun the contrast material in the diseased leg, with resulting poor contrast opacification of the arteries distal to the obstruction. Despite the excellent arterial diagnostic capabilities of CTA, considerations of intravenous contrast on renal function, radiation, and blooming artifact from dense calcium need to be considered. However, advances in CTA technology have continued to minimize these concerns. Axial images can be reconstructed in coronal and sagittal planes and as 3D maximumintensity projections, 3D surface shaded display, and 3D volume-rendered images. Magnetic Resonance Angiography Both non-contrast and contrast-enhanced magnetic resonance angiography (MRA) techniques can be used to assess the peripheral vasculature. Contrast-enhanced MRA has had increasing sensitivity and specificity for detection of vascular abnormalities. Non-contrast steady-state free precession MRA provides accurate assessment of large arterial steno-occlusive disease, and 2D time-of-flight imaging provides reasonable assessment of distal arteries with slow flow. Rapid evaluation of the extremity arteries can be performed with multistation technique. In addition, lower leg arterial evaluation can be supplemented by using time-resolved techniques such as time-resolved imaging with contrast kinetics (TRICKS). This approach provides highly accurate assessment of small vessel arteries. Moreover, it shows temporal changes in blood flow and thus allows detection of dominant collateral pathways in the presence of an occlusion and assessment of venous drainage pathways. MRA with protein-bound gadolinium allows highresolution imaging of arteries and veins for an accurate assessment of small vessel disease. Catheter Angiography Catheter angiography remains the gold standard for evaluation of the peripheral arteries. Current angiography systems allow multistation overlapping imaging of both lower extremities with a catheter positioned in the lower abdominal aorta. Imaging through the delayed phase until all the collateral pathways are filled is important to assess distal reconstitution in the presence of occlusion. As in CT, adequate contrast material injection and temporal acquisition are necessary, and concerns of contrast-induced nephropathy and radiation exposure remain. Given the advances in techniques and the exquisite images from both CTA and MRA, catheter angiography can now be limited to interventional procedures. Selected References 1. Taylor-Piliae RE et al: Ankle brachial index screening in asymptomatic older adults. Am Heart J. 161(5):979-85, 2011 2. Wallin D et al: Computed tomographic angiography as the primary diagnostic modality in penetrating lower extremity vascular injuries: a level I trauma experience. Ann Vasc Surg. 25(5):620-3, 2011 3. Chan D et al: Imaging evaluation of lower extremity infrainguinal disease: role of the noninvasive vascular laboratory, computed tomography angiography, and magnetic resonance angiography. Tech Vasc Interv Radiol. 13(1):11-22, 2010 4. Eiberg JP et al: Duplex ultrasound scanning of peripheral arterial disease of the lower limb. Eur J Vasc Endovasc Surg. 40(4):507-12, 2010 5. Bonel HM et al: MR angiography of infrapopliteal arteries in patients with peripheral arterial occlusive disease by using Gadofosveset at 3.0 T: diagnostic accuracy compared with selective DSA. Radiology. 253(3):879-90, 2009 6. Met R et al: Diagnostic performance of computed tomography angiography in peripheral arterial disease: a systematic review and meta-analysis. JAMA. 301(4):415-24, 2009 7. Peng PD et al: CT angiography effectively evaluates extremity vascular trauma. Am Surg. 74(2):103-7, 2008 8. Begelman SM et al: Noninvasive diagnostic strategies for peripheral arterial disease. Cleve Clin J Med. 73 Suppl 4:S22-9, 2006 9. Deutschmann HA et al: Routine use of three-dimensional contrast-enhanced moving-table MR angiography in patients with peripheral arterial occlusive disease: comparison with selective digital subtraction angiography. Cardiovasc Intervent Radiol. 29(5):762-70, 2006 10. Willens HJ et al: Relationship of peripheral arterial compliance and standard cardiovascular risk factors. Vasc Endovascular Surg. 37(3):197-206, 2003 11. Lundin P et al: Imaging of aortoiliac arterial disease. Duplex ultrasound and MR angiography versus digital subtraction angiography. Acta Radiol. 41(2):125-32, 2000

Lower Extremity Vasculature Anatomy > Table of Contents > Section 16 - Peripheral Vasculature > Introduction and Overview > Lower Extremity Vasculature Anatomy 1196

Diagnostic Imaging Cardiovascular Lower Extremity Vasculature Anatomy Suvranu Ganguli, MD TERMINOLOGY Abbreviations Common femoral artery (CFA) Superficial femoral artery (SFA) Profunda femoris artery (PFA) Synonyms Internal iliac artery = hypogastric artery Small saphenous vein = lesser saphenous vein IMAGING ANATOMY Anatomy Relationships Abdominal aorta bifurcates into common iliac arteries Common iliac arteries are 3-6 cm long, 8-10 mm in diameter Divide into internal/external iliac arteries Internal iliac arteries bifurcate into anterior and posterior divisions; supply pelvic muscles, viscera Anterior division yields inferior gluteal, obturator, internal pudendal, vesicle, uterine arteries Posterior division yields superior gluteal, iliolumbar, lateral sacral arteries External iliac arteries become CFA at inguinal ligament Ligament delineated by origins of inferior epigastric and deep circumflex iliac arteries CFA is usually 5-7 cm long, 5-9 mm in diameter Bifurcates into SFA and PFA CFA and vein are within femoral sheath, a continuation of abdominal wall fascia Femoral nerve is outside PFA origin is posterolateral to SFA origin Main trunk has deep course adjacent to femur Anastomoses with SFA/popliteal branches Supplies proximal hip Medial and lateral femoral circumflex arteries Important collateral pathway in proximal SFA occlusion or stenosis SFA provides dominant in-line arterial supply in thigh Courses beneath sartorius, anterior to femoral vein Exits Hunter canal at adductor hiatus, becomes popliteal artery Multiple muscular branches; supreme geniculate (medial) branch is largest Popliteal artery extends from adductor hiatus to calf Knee joint delineates above-/below-knee segments Levels influence intervention choices, outcomes Yields superior medial, superior lateral, middle, inferior medial, and inferior lateral geniculate arteries Bifurcates into anterior tibial, tibioperoneal trunk Tibioperoneal trunk divides into posterior tibial, peroneal arteries 3 below-knee runoff arteries Anterior tibial artery Courses to foot in anterior compartment of calf Continues into foot as dorsalis pedis artery Posterior tibial artery Extends from upper calf to medial malleolus Contained in deep posterior calf compartment Terminates as medial and lateral plantar arteries Forms plantar arch of foot Peroneal artery Descends posteromedial to fibula in deep posterior calf compartment Ends in characteristic “forked” anterior and posterior perforating branches ANATOMY IMAGING ISSUES Lower Extremity Vascular Pathology Atherosclerotic occlusive disease Acute limb ischemia Embolic vs. thrombotic occlusion Endovascular or surgical treatment 1197

Diagnostic Imaging Cardiovascular Chronic limb ischemia Symptoms relate to level of occlusion, presence and quality of collaterals, and comorbidities Medical, endovascular, and surgical management Aneurysms True or false (pseudoaneurysm) Common femoral artery aneurysm Most frequent site for pseudoaneurysm; secondary to catheterization, surgical anastomosis Popliteal artery aneurysm Most common lower extremity aneurysm Presents with limb ischemia in > 50% Thromboembolic complications common Arteriovenous malformations Lower extremities are most common location Congenital abnormalities Persistent sciatic artery Internal iliac artery continues as sciatic artery and then as popliteal artery May have hypoplastic SFA; sciatic artery dominates blood supply to lower extremity (complete form) Cystic adventitial disease Focal cystic mucin accumulation in adventitia Cysts cause vascular compression, claudication Popliteal artery is most often affected Popliteal artery entrapment Artery deviates around gastrocnemius muscle or is compressed between muscular structures Claudication; may progress to occlusion Peripheral vascular surgical reconstruction Vascular conduit bypass of diseased arterial segment Trauma 1/3 cases vascular trauma involves extremities Penetrating or blunt trauma Arterial injury with 30-40% of knee dislocations Vasculitis Buerger disease (most common); others (uncommon) Venous diseases Chronic venous insufficiency Chronic swelling, pigmentation, venous stasis ulcers; secondary to deep vein thrombosis (postthrombotic syndrome) Varicose veins, incompetent perforators Deep vein thrombosis Blood clots in deep veins of lower extremity Risk of embolism to pulmonary arteries May result in chronic venous insufficiency Klippel-Trenaunay syndrome: Congenital disorder Capillary malformations (port-wine stain), soft tissue or bone hypertrophy, varicose veins or venous malformations affecting extremity Venous malformations Congenital abnormality; deep or superficial malformations; sclerotherapy for treatment P.16:5

Image Gallery PELVIC AND LOWER EXTREMITY ARTERIAL ANATOMY

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(Top) AP MIP from MR angiogram of the lower abdomen and pelvis displays the arteries of the pelvis. (Middle) Single AP image from catheter angiography of the region of the right hip displays the arteries of the hip and thigh. (Bottom) Single AP image from catheter angiography of the region of the thigh displays the arterial anatomy. P.16:6

LOWER EXTREMITY ARTERIAL ANATOMY

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(Top) Single AP image from catheter angiography of the region of the knee displays the arterial anatomy. (Middle) AP MIP from MR angiogram of the left lower extremity displays the runoff arteries below the knee. (Bottom) Single lateral film from catheter angiography of the foot displays the arterial anatomy of the foot. P.16:7

UPPER AND LOWER EXTREMITY VENOUS ANATOMY

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(Top) AP MIP from MR venogram of the pelvis and thighs displays the veins of the lower pelvis and thighs. (Middle) Single lateral radiograph from ascending venogram of the lower leg displays the veins below the knee. (Bottom) Single AP radiograph from a left upper extremity venogram displays the veins of the upper arm.

Vasculature of the Trunk Subclavian Artery Stenosis/Occlusion > Table of Contents > Section 16 - Peripheral Vasculature > Vasculature of the Trunk > Subclavian Artery Stenosis/Occlusion Subclavian Artery Stenosis/Occlusion Suvranu Ganguli, MD Key Facts Terminology Subclavian artery luminal narrowing or blockage Imaging Most common atherosclerosis locations: Subclavian artery origin proximal to vertebral artery origin 85% involve left subclavian artery Best imaging tool: MRA and CTA with contrast Poststenotic dilatation (severe stenosis) Long, smoothly tapered stenosis with dissection Reversed vertebral artery flow (subclavian steal syndrome) 1201

Diagnostic Imaging Cardiovascular Collaterals in chest wall and shoulder Vessel compression or occlusion at thoracic outlet; poststenotic aneurysm (thoracic outlet syndrome) Catheter angiography is gold standard but limited in assessing arterial wall Clinical Issues BP difference between arms can help identify patients who need further vascular assessment Subclavian steal syndrome: Confluence of 2 vertebral arteries at foramen magnum enables retrograde ipsilateral vertebral collateral flow to subclavian artery Atherosclerotic subclavian artery occlusion usually asymptomatic Arm claudication or posterior fossa symptoms may develop Distal embolization (from ulcerated atherosclerotic plaque or poststenotic aneurysm) No treatment for asymptomatic cases Endovascular treatment for symptomatic patients: Angioplasty &/or stenting Arterial bypass surgery if endovascular treatment unsuccessful; endarterectomy

(Left) Axial CTA through the great vessels shows a high-grade ostial atherosclerotic stenosis of the left subclavian artery, consisting of both calcified and noncalcified plaque with circumferential luminal narrowing. The left vertebral artery arises from the subclavian artery more cephalad. (Right) Coronal reformat CTA in the same patient shows a moderate-grade stenosis of the origin of the left subclavian artery from the aorta.

(Left) Anteroposterior MIP of T1 C+ subtraction MR clearly depicts a high-grade stenosis of the mid left subclavian artery. (Right) Right anterior oblique thoracic aortography depicts a high-grade ostial stenosis of the left subclavian artery. Incidental note is made of a common origin of the brachiocephalic and left common carotid arteries (“bovine arch”). The left vertebral artery is not seen because of reversed flow due to the subclavian stenosis, and it opacifies on delayed images. P.16:9 1202

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TERMINOLOGY Definitions Subclavian artery luminal narrowing or obliteration Associated Syndromes Subclavian artery stenosis or obstruction; subclavian occlusive disease; subclavian steal syndrome; subclavian steal phenomenon; thoracic outlet syndrome IMAGING General Features Best diagnostic clue Focal narrowing or occlusion of subclavian artery Location 85% involve left subclavian artery (atherosclerosis) Most common atherosclerosis locations: Subclavian artery origin proximal to vertebral artery origin Size Stenosis graded as mild (< 50%), moderate (50-70%), and high (> 70%) Morphology Eccentric atherosclerotic plaque; may evolve to concentric stenosis or occlusion CT Findings CTA Eccentric irregularly calcified, noncalcified, or mixed plaque with resulting stenosis/occlusion Atherosclerotic ulcerated plaque shows irregular contrast-filled outpouchings Concentric mural soft tissue thickening in vasculitis Delayed mural enhancement in active vasculitis Low-density intimal flap in dissection Differential enhancement of true and false lumina False lumen larger than true lumen MR Findings T1WI Pre-contrast T1 GRE shows mural thickening, dissection flap, or atherosclerotic plaque High signal intensity in intramural hematoma T2WI SSFP (bright blood) may show low-signal intimal flap and intermediate-signal intramural hematoma, mural thickening, and plaque T1WI C+ Mural thickening and enhancement (vasculitis) More sensitive in assessment of mural enhancement than CT Ulcerated atherosclerotic plaque shows irregular contrast-filled outpouching MRA Contrast-enhanced MRA (CE-MRA) shows luminal stenosis, irregularities, or occlusion Limited evaluation of vessel wall, flow dynamics Phase-contrast MRA (PC-MRA) confirms reverse flow (usually dark signal) in vertebral artery from subclavian steal syndrome Time-resolved MRA (TR-MRA) images mimic catheter angiogram: Assess real-time flow dynamics High-grade proximal subclavian artery stenosis with retrograde flow in ipsilateral vertebral artery and distal subclavian artery in subclavian steal syndrome Ultrasonographic Findings Color Doppler Turbulence and aliasing at stenosis Duplex ultrasound findings Absence of flow in occluded segment Elevated flow velocity in stenosis (peak systolic velocity ≥ 300 cm/s) Poststenotic flow disturbance/reduced velocity Damped or monophasic Doppler waveforms in arterial segment distal to stenosis (assuming no retrograde flow from ipsilateral vertebral artery) Reversed or biphasic flow in ipsilateral vertebral artery in subclavian steal syndrome Angiographic Findings Conventional 1203

Diagnostic Imaging Cardiovascular Thoracic arch aortogram prior to selective angiography; Left anterior oblique (LAO) projection Luminal diameter reduced in focal stenosis or occlusion; ulcerated plaque with irregular web-like stenosis with contrast-filled outpouching Acute thrombosis/embolus shows intraluminal filling defect or occlusion CTA, MRA, or DSA findings Poststenotic dilatation (severe stenosis) Long, smoothly tapered stenosis with dissection Reversed vertebral artery flow (subclavian steal syndrome) Collaterals in chest wall and shoulder Soft tissue masses, scar or clavicular fracture (if obstructed by extrinsic compression) Vessel compression or occlusion at thoracic outlet; poststenotic aneurysm (thoracic outlet syndrome) Imaging Recommendations Best imaging tool MRA and CTA with contrast Catheter angiography is gold standard but limited in assessing arterial wall MRA, CTA, or DSA for pretreatment assessment MR/MRA: MRA with double dose (0.2 mmol/kg); timing bolus with region of interest (ROI) in ascending aorta; 2 passes (early arterial and venous) TR-MRA (4-5 mL contrast at 3 mL/s for flow pattern) Axial and coronal pre- and post-T1 GRE to assess arterial wall Phase-contrast MR to determine flow direction CTA: Bolus tracking technique with ROI in aortic arch or ascending aorta; 80 mL of contrast at 3 mL/s Axial 0.75-1.5 mm collimated volumetric acquisitions 3 mm coronal and sagittal reconstructions Inject contrast from asymptomatic side in CTA/MRA; right IV access for bilateral study 30-40 mL saline flush (avoids venous contrast artifact) DIFFERENTIAL DIAGNOSIS Thoracic Outlet Syndrome Arm pain from compression of neurovascular bundle at thoracic outlet Most symptoms from brachial plexus compression Also from subclavian artery or vein compression P.16:10

Thoracic outlet boundaries: Clavicle and 1st rib, anterior and posterior scalene muscles Changes in Doppler waveforms or arm blood pressure during provocative maneuvers (e.g., Adson maneuver) Compression of subclavian artery at thoracic outlet, possible poststenotic aneurysm (diagnostic) Imaging in neutral and stress (abduction) positions Embolization/Iatrogenic 30% upper-extremity ischemia embolic 30% upper-extremity ischemia iatrogenic (e.g., arterial puncture, hemodialysis access) Vasculitis Luminal irregularity Presents at younger age Mural thickening ± enhancement Dissection Intimal flap separating true and false lumens can extend into great vessels Can cause subclavian stenosis or occlusion PATHOLOGY General Features Etiology Atherosclerosis (˜ 30% of upper extremity ischemia) Emboli: Most commonly of cardiac origin Other causes Arterial dissection Neoplasm (e.g., Pancoast tumor) Trauma (blunt or penetrating, iatrogenic) Scar (e.g., post radiation, fibrosing mediastinitis) 1204

Diagnostic Imaging Cardiovascular Thoracic outlet syndrome Fibromuscular dysplasia Vasculitis (e.g., Takayasu, giant cell arteritis) Congenital absence of subclavian artery (rare) Associated abnormalities Coronary artery disease, MI, TIA, stroke CLINICAL ISSUES Presentation Most common signs/symptoms Acute ischemia: Arm/hand pain, cold hand with delayed capillary refill, decreased/absent pulses Chronic ischemia: Diminished pulses; differential arm pressures; dizziness if subclavian steal syndrome Commonly asymptomatic BP difference between arms can help identify patients who need further vascular assessment Useful, noninvasive indicator of risk of vascular disease and death Other signs/symptoms Upper extremity claudication (exercise-induced ischemic pain), rest pain, or tissue loss rare Vertebrobasilar ischemia (subclavian steal syndrome) Confluence of 2 vertebral arteries at foramen magnum enables retrograde ipsilateral vertebral collateral flow to subclavian artery Distal embolization (from ulcerated atherosclerotic plaque or poststenotic aneurysm) Intermittent arm, shoulder, and neck pain (thoracic outlet syndrome) Chest pain (post left, internal mammary artery, coronary artery, bypass graft, and subsequent subclavian artery origin stenosis) Decreased pulses on side of subclavian stenosis 20-30 mm Hg arm BP difference is diagnostic Cold, blanched extremity with acute occlusion Demographics Age Usually > 65 years Gender Males and females equally affected Epidemiology 12-19% of subclavian artery stenoses occur in patients with peripheral vascular disease Natural History & Prognosis Atherosclerotic subclavian artery occlusion usually asymptomatic Possible arm claudication or posterior fossa symptoms Symptomatic dissection: Requires angioplasty/stenting or bypass surgery Fibromuscular dysplasia and vasculitis are progressive Possible persistent or progressive symptoms with thoracic outlet syndrome Treatment No treatment for asymptomatic cases Endovascular treatment for symptomatic patients Angioplasty &/or stenting Arterial bypass surgery if endovascular treatment unsuccessful (e.g., axillo-axillary, or carotid-subclavian bypass), endarterectomy Decompression surgery for thoracic outlet syndrome Thoracic sympathectomy DIAGNOSTIC CHECKLIST Consider Subclavian steal syndrome in patients with vertebrobasilar insufficiency symptoms and exercised-induced upper extremity ischemia Coronary-subclavian syndrome in patients with internal mammary cardiac bypass surgery and angina Image Interpretation Pearls Acute emboli appear as intraluminal filling defects SELECTED REFERENCES 1. Clark CE et al: Association of a difference in systolic blood pressure between arms with vascular disease and mortality: a systematic review and meta-analysis. Lancet. 379(9819):905-14, 2012 2. Song L et al: Endovascular stenting vs. extrathoracic surgical bypass for symptomatic subclavian steal syndrome. J Endovasc Ther. 19(1):44-51, 2012 1205

Diagnostic Imaging Cardiovascular 3. Labropoulos N et al: Prevalence and impact of the subclavian steal syndrome. Ann Surg. 252(1):166-70, 2010 4. Liava'a M et al: Progressive subclavian artery stenosis causing late coronary artery bypass graft failure as a result of coronary-subclavian artery steal. J Thorac Cardiovasc Surg. 135(2):438-9, 2008 5. Palchik E et al: Subclavian artery revascularization: an outcome analysis based on mode of therapy and presenting symptoms. Ann Vasc Surg. 22(1):70-8, 2008 P.16:11

Image Gallery

(Left) Anteroposterior CTA 3D curved reformation reconstruction of the subclavian and vertebral artery shows a highgrade atherosclerotic stenosis of the right subclavian artery, which is not as commonly affected as the left subclavian artery. (Right) Color Doppler ultrasound of the distal right subclavian artery shows abnormal, dampened monophasic waveforms distal to the stenosis in the proximal right subclavian artery.

(Left) Axial PC-MRA confirms reversal of flow in the left vertebral artery from subclavian steal syndrome. There is lack of signal in the left vertebral artery . Normal cranial flow in the right vertebral artery is identified in same direction as the carotids . (Right) Anteroposterior angiography with the catheter in the left vertebral artery reveals subclavian steal syndrome with flow reversed in the right vertebral artery , which flows into the right subclavian artery , to bypass the upstream stenosis.

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(Left) Anteroposterior catheter angiography of the right subclavian artery from an ipsilateral brachial approach depicts a complete occlusion of the mid right subclavian artery. A focal dissection of the artery at the occlusion is also identified. (Right) Anteroposterior catheter angiography after recannulization and stenting of the occlusion from an ipsilateral brachial approach shows good results. The origin of the right vertebral artery is now well identified.

Subclavian Vein Thrombosis > Table of Contents > Section 16 - Peripheral Vasculature > Vasculature of the Trunk > Subclavian Vein Thrombosis Subclavian Vein Thrombosis T. Gregory Walker, MD, FSIR Key Facts Terminology Subclavian vein thrombosis: Completely or partially occlusive thrombus formation in subclavian vein Typically has associated extensive venous collaterals Paget-Schroetter syndrome (effort thrombosis): Axillary-subclavian vein thrombosis associated with strenuous and repetitive upper extremity activity Caused by anatomical abnormalities of thoracic outlet and repetitive trauma to subclavian vein Imaging Ultrasound: Noncompressible vein or intraluminal thrombus are diagnostic of venous thrombosis CECT and CTV: Avascular thrombus; seen as low-density intraluminal filling defect Contrast flows around periphery of thrombus Extensive venous collaterals are typically present Post-contrast T1 2D GRE or 3D GRE MRV Shows perivascular inflammatory soft tissue with wall thickening and enhancement Low-signal hypovascular thrombus High-signal contrast around thrombus Pathology Primary subclavian vein thrombosis (uncommon) Due to effort, trauma, thoracic outlet abnormality Secondary subclavian vein thrombosis (common) Systemic hypercoagulability from various causes Related to central venous catheter in 12-30% Clinical Issues Standard anticoagulation therapy is used most often Higher recanalization rates if fibrinolytic agents used Endovascular: Mechanical thrombectomy Surgery: 1st rib and anterior scalene resections Need surgical decompression for thrombosis due to thoracic outlet or Paget-Schroetter syndromes

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(Left) Sagittal color Doppler ultrasound demonstrates (A) the presence of hypoechoic material centrally within the left subclavian vein, with flow along the periphery and (B) noncompressibility of the vein, consistent with a partially occlusive thrombus. (Right) Spectral waveform analysis shows (C) absent flow centrally in the subclavian vein as a result of thrombotic occlusion. (D) A venous waveform is detectable along the periphery of the thrombus, indicating that some blood flow is present and the thrombus is likely subacute.

(Left) Coronal CTA shows classic findings of subclavian vein thrombosis. The avascular thrombus appears as a lowdensity filling defect , with contrast flowing around the periphery , just as blood flow was seen by Doppler US. This characteristic appearance is termed the “tram track” sign. (Right) DSA shows the venographic appearance of venous thrombosis. In this case, there are numerous intraluminal filling defects seen in multiple veins of the proximal left upper extremity, all of which also exhibit the “tram track” sign. P.16:13

TERMINOLOGY Definitions Subclavian vein thrombosis: Completely or partially occlusive thrombus formation in subclavian vein Typically has associated extensive venous collaterals Paget-Schroetter syndrome (effort thrombosis): Axillary-subclavian vein thrombosis associated with strenuous and repetitive upper extremity activity Caused by anatomical abnormalities of thoracic outlet and repetitive trauma to subclavian vein IMAGING General Features Best diagnostic clue 1208

Diagnostic Imaging Cardiovascular Intraluminal thrombus occluding subclavian vein Extensive venous collaterals are usually present Location Right subclavian vein is involved in 2/3 of cases Radiographic Findings Radiography Mass at thoracic outlet or cervical rib may be present Ultrasonographic Findings Either intraluminal thrombus or noncompressibility of vein is diagnostic of venous thrombosis Thrombosis excluded if suspected vein is compressible Vein location behind clavicle limits US evaluation Dilated collateral may be mistaken for normal vein Abnormal duplex Doppler flow pattern is only suggestive of venous thrombosis With Valsalva maneuver, vein size normally increases Due to reduction in flow With sniff test, vein size normally decreases Due to increase in flow Need further imaging to confirm thrombosis Appearance of vein/thrombus changes over time Acute venous thrombosis Markedly distended vein Hypo/isoechoic intraluminal thrombus Subacute venous thrombosis Increased thrombus echogenicity/heterogeneity Shrinkage of thrombus, decreased vein size Chronic stage of venous thrombosis Possible return to normal appearance May have variable vein caliber, focal or diffuse wall thickening, plaque-like or linear scars/webs CT Findings CECT and CT venography (CTV) Thrombus avascular; seen as low-density filling defect Contrast flows around periphery of intraluminal thrombus; has characteristic appearance “Tram track” sign on coronal and sagittal images “Polo mint” sign on axial images Dilated vein (acute thrombosis) May have accompanying venous collaterals Postthrombotic changes in chronic thrombosis Severe venous narrowing (stricture) May have barely visible residual lumen Eccentric linear filling defect(s) Represent intraluminal fibrotic scars/synechiae Extensive venous collaterals are typically present Occasional calcification Tumor thrombus may show partial enhancement May show abnormal adjacent/surrounding structures e.g., cervical rib, mass lesion MR Findings T1WI Acute thrombus may appear as high signal T2WI Bright blood SSFP shows thrombus as low signal MRV Time-resolved MRA (TR-MRA) findings Mimic contrast venogram Lack of venous opacification Collateral flow pattern may be present Intraluminal thrombus is difficult to appreciate Contrast-enhanced MRA (CE-MRA) findings Acute: Dark signal thrombus within distended vein 1209

Diagnostic Imaging Cardiovascular Chronic: Vein may be markedly stenotic or occluded Lack of contrast opacification of vein Eccentric, linear, wall-adherent, filling defect (thrombus, organized fibrotic plaque) Web-like stenosis Extensive dilated tortuous collaterals: Chest wall, paravertebral, cervical, and axillary veins Post-contrast T1 2D GRE or 3D GRE (VIBE) Better demonstrates thrombus and vessel wall Shows perivascular inflammatory soft tissue with wall thickening and enhancement Low-signal hypovascular thrombus High-signal contrast around thrombus Tumor thrombus may enhance internally Angiographic Findings DSA venography is difficult in 20% due to arm edema Thrombus is seen as central filling defect Peripheral luminal contrast flow (“tram track”) Venous occlusion with extensive collaterals Pericatheter thrombus/fibrin Image in neutral and stress (arm abduction) positions Important in suspected thoracic outlet syndrome Pitfall: Absent opacification of normal cephalic vein Imaging Recommendations Best imaging tool Contrast venography/DSA remains gold standard However, not as versatile as MR Protocol advice Duplex ultrasound: Use as first line of imaging Limited to distal subclavian vein and arm veins MR: Pre- and post-contrast, fat-saturated T1 GRE Include coronal acquisitions MRV: Double-dose gadolinium, 2-3 passes 40-second delay between 2nd and 3rd passes Include coronal acquisitions TR-MRA: Ipsilateral injection of < 5 mL of contrast Temporal resolution 1.2 seconds Obtain images in neutral and stress positions in suspected thoracic outlet syndrome CTV: Ipsilateral injection of 120-140 mL of contrast Arterial phase (ROI: Pulmonary artery) and 2-minute delayed venous phase from C3 to heart or simultaneous bilateral antecubital injections DSA venography: 20 mL contrast injected from ipsilateral antecubital vein access P.16:14

Perform separate injection to see superior vena cava May rarely require bilateral injections Dynamic images in neutral and stress positions for suspected thoracic outlet syndrome DIFFERENTIAL DIAGNOSIS Extrinsic Venous Compression Venous thrombosis (due to stasis) may be present Causes: Lymphadenopathy, Pancoast tumor, scarring (e.g., post radiation) MR and CT are best modalities for evaluation Thoracic Outlet Syndrome Vein pinched by 1st rib, clavicle, and scalene muscles Intermittent arm pain/swelling Possible arterial ischemia & brachial plexus neuropathy May be associated with subclavian vein thrombosis Tumor Thrombus Local extension of malignant tumor into vein Dilated vein with filling defect 1210

Diagnostic Imaging Cardiovascular Partial enhancement of thrombus on delayed scan PATHOLOGY General Features Etiology Underlying cause usually present; often multifactorial Primary subclavian vein thrombosis (uncommon) Causes: Effort induced, traumatic, thoracic outlet abnormality, or unknown No underlying hypercoagulable state Repeated trauma & stasis predispose to thrombosis > 75% present within 24 hours after strenuous effort Cervical rib/other variants can contribute to thoracic outlet obstruction and effort thrombosis Medical urgency to prevent debilitation from permanent subclavian occlusion Secondary subclavian vein thrombosis (common) Systemic hypercoagulability from various causes Dehydration; surgery; nephrotic syndrome; oral contraceptives; immobility; pregnancy; protein C, protein S, and antithrombin deficiencies; cancer Thrombosis related to central venous catheter in 12-30% of cases; larger polyvinyl catheters more thrombogenic than small silicone catheters Intimal injury from intravenous drug abuse (e.g., heroin, cocaine), pacemaker wires Obstruction from tumor, lymphadenopathy, scar Typically insidious onset of symptoms Associated abnormalities Often associated with axillary vein thrombosis Palpable tender axillary “cord” Occasional thoracic outlet abnormality CLINICAL ISSUES Presentation Most common signs/symptoms Upper extremity swelling (nonpitting edema) Other signs/symptoms Arm pain ranging from dull ache to severe discomfort Visible collaterals in shoulder and thorax Demographics Epidemiology Primary subclavian vein thrombosis: Young males Secondary subclavian vein thrombosis: Older patients M=F Natural History & Prognosis Postthrombotic syndrome (4-22%): Venous hypertension due to venous outflow obstruction 40-70% incidence after effort thrombosis Without treatment, may not recanalize Results in chronic occlusion Organized fibrotic tissue eventually replaces vein Extensive collaterals provide central venous return Treatment Standard anticoagulation therapy is used most often Heparin followed by warfarin Catheter-related thrombosis may require line removal Use of fibrinolytic agents such as tissue plasminogen activator (tPA) offers higher recanalization rates Consider in young patient with effort thrombosis or those needing hemodialysis or long-term intravenous access Best results within 1 week of thrombosis May require up to 72 hours to achieve total lysis Risk of bleeding: Major 0-4%, minor 0-40% Endovascular: Mechanical thrombectomy yields rapid debulking and restoration of vein patency Chronic thrombus > 1 week may not benefit May need angioplasty if stenosis is present Surgery: 1st rib and anterior scalene resections Need surgical decompression for thrombosis due to thoracic outlet or Paget-Schroetter syndromes 1211

Diagnostic Imaging Cardiovascular Otherwise, vein will reocclude even after endovascular restoration of patency Vein patch angioplasty: Chronic stenosis/occlusion; failed response to fibrinolytic therapy in primary subclavian vein thrombosis DIAGNOSTIC CHECKLIST Consider Effort thrombosis in young patient with sudden upper extremity swelling following physical activity Intermittent nonthrombotic subclavian vein obstruction or lymphedema if absent thrombus and patent, normalsized vein in neutral position Image Interpretation Pearls Always look for associated pulmonary emboli SELECTED REFERENCES 1. Chin EE et al: Sonographic evaluation of upper extremity deep venous thrombosis. J Ultrasound Med. 24(6):829-38, 2005 2. Baarslag HJ et al: Diagnosis and management of deep vein thrombosis of the upper extremity: a review. Eur Radiol. 14(7):1263-74, 2004 3. Sharafuddin MJ et al: Endovascular management of venous thrombotic diseases of the upper torso and extremities. J Vasc Interv Radiol. 13(10):975-90, 2002 4. Thornton MJ et al: A three-dimensional gadolinium-enhanced MR venography technique for imaging central veins. AJR Am J Roentgenol. 173(4):999-1003, 1999 P.16:15

Image Gallery

(Left) Graphic of the thoracic outlet shows the relationship of the neurovascular bundle to the adjacent musculoskeletal structures. The subclavian vein courses behind the clavicle & anterior to the anterior scalene muscle & 1st rib . The musculoskeletal structures may compress the vein, causing thoracic outlet syndrome & predisposing to subclavian vein thrombosis. (Right) Coronal CTA in a man with left arm swelling shows a filling defect in the subclavian vein , consistent with venous thrombosis.

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(Left) DSA of the left axillosubclavian venous segment with the shoulder in neutral position shows narrowing and irregularity of the left subclavian vein at the junction of the clavicle and 1st rib. Though the vein is patent, there are multiple venous collaterals . (Right) DSA with the left arm abducted shows that the subclavian vein lumen is occluded during this provocative maneuver and central venous filling is via collaterals . The findings are typical of venous thoracic outlet syndrome.

(Left) Thoracic outlet abnormalities or repetitive strenuous activities, as in effort thrombosis or Paget-Schroetter syndrome, may cause chronic subclavian vein injury. (A) The left subclavian vein is occluded , with numerous venous collaterals . (B) A guidewire has been placed across the venous occlusion. (Right) (C) A PTA balloon has been inflated in the occluded segment. (D) Post-angioplasty DSA shows restored patency, with residual narrowing . The patient will require surgical decompression.

Iliac Artery Occlusive Disease > Table of Contents > Section 16 - Peripheral Vasculature > Vasculature of the Trunk > Iliac Artery Occlusive Disease Iliac Artery Occlusive Disease T. Gregory Walker, MD, FSIR Key Facts Terminology Iliac artery occlusive disease: Stenosis or occlusion of ≥ 1 major pelvic arteries Leriche syndrome: Aortoiliac occlusive disease resulting in classic clinical triad of buttock/thigh claudication, absent femoral pulses, and impotence Imaging Noninvasive arterial examination 1213

Diagnostic Imaging Cardiovascular Duplex ultrasound: Assesses lesion severity/extent ABI: Ratio of ankle and brachial arterial pressures Segmental limb pressures: Localizes lesion(s) via multilevel evaluation of limb arterial pressures Pulse volume recording: Measures changes in limb volume at various levels; shows blood flow changes CTA: Accurately depicts stenoses, occlusions, and collaterals in format similar to angiography DSA: Gold standard for vessel characterization Pathology Peripheral artery disease: Occlusive disease due to atherosclerotic plaques Most common etiology in older patients Clinical Issues Iliac artery occlusive disease typically causes buttock and thigh claudication Symptoms vary with extent of arterial collaterals If strong clinical evidence of pelvic arterial disease or abnormal noninvasive arterial examination Use CTA or MRA to confirm localized iliac disease Treatment options Endovascular: Angioplasty &/or stenting Surgical: Vascular bypass or endarterectomy Diagnostic Checklist Consider endovascular therapy as first-line treatment

(Left) Noninvasive arterial examination in a man with left buttock and thigh claudication shows multilevel uniformly dampened biphasic arterial waveforms in left infrainguinal arteries, consistent with iliac arterial inflow disease. An ABI of 0.41 is markedly abnormal but similar to ratios at all other infrainguinal levels, also consistent with inflow disease. (Right) Coronal CTA confirms left CIA occlusion at the origin , with reconstitution of the internal and external iliac arteries via extensive collaterals .

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(Left) Pelvic DSA via a catheter introduced from the right common femoral artery also shows the left common iliac artery occlusion and distal reconstitution . Orthopedic hardware is evident as a subtracted density overlying the upper pelvis. (Right) The patient was treated with left common iliac artery recanalization from a common femoral artery access, followed by placement of “kissing” common iliac artery stents . The subtracted densities overlying both distal common iliac arteries are due to the orthopedic hardware . P.16:17

TERMINOLOGY Definitions Iliac artery occlusive disease: Stenosis or occlusion of ≥ 1 major pelvic arteries Leriche syndrome: Aortoiliac occlusive disease resulting in classic clinical triad of buttock/thigh claudication, absent femoral pulses, and impotence IMAGING General Features Best diagnostic clue Narrowed (stenotic) or completely occluded arteries Well demonstrated by multiple imaging modalities Poststenotic dilatation distal to severe stenosis Severe stenosis may progress to occlusion Collaterals imply chronic rather than acute occlusion Location Common iliac arteries (CIAs) originate at aortic bifurcation, extend into midpelvis, and bifurcate into internal (hypogastric) and external iliac arteries (IIAs and EIAs) IIAs extend from CIA bifurcation Bifurcate into anterior and posterior divisions EIAs extend from CIA bifurcation to common femoral arteries (CFAs) at level of inguinal ligament Deep circumflex iliac and inferior epigastric artery origins denote level of CFA; anatomically corresponds to inguinal ligament Noninvasive Arterial Examination Duplex ultrasound Characterizes lesion morphology/severity/extent Findings in 51-75% stenosis Prestenotic segment: Normal Intrastenotic segment: Peak systolic velocity (PSV) elevated > 2× normal Poststenotic segment: Partial turbulence Findings in 76-99% stenosis Prestenotic segment: Increased pulsatility Intrastenotic segment: PSV elevated > 4× normal Poststenotic segment: Marked turbulence 1215

Diagnostic Imaging Cardiovascular Obesity, bowel gas may limit iliac artery assessment Ankle-brachial index (ABI): Ratio of arterial pressures at ankle and brachial levels Performed with blood pressure (BP) cuff and continuous Doppler Segmental limb pressures: BP cuffs placed on leg at 4 levels; arterial pressures obtained Allows for approximate localization of disease BP drop ≥ 20 mm Hg and dampened waveform indicates flow-limiting lesion between cuffs Pulse volume recording (PVR): Combines segmental limb pressures with air plethysmography Multiple pneumatic cuffs placed along lower extremity; inflated with standardized volume of air Measure changes in limb volume at various levels Reflect changes in blood flow CT Findings CTA Accurately depicts stenoses, occlusions, and collateral vasculature in format similar to angiography Also depicts adjacent nonvascular anatomy Needs multidetector scanner, high contrast dose, rapid bolus injection, & sophisticated postprocessing Contrast-related renal dysfunction/allergy possible Heavily calcified plaque may limit rendered images Include source images for accurate interpretation MR Findings MRA Time-of-flight technique is inaccurate Due to flow-related artifacts Gadolinium-enhanced MRA is more accurate Similar findings to those of angiography or CTA but may inaccurately overestimate severity of stenoses Angiographic Findings Current gold standard for vessel characterization Accurately demonstrates arterial anatomy, stenoses, occlusions, and collateral arterial pathways Invasive procedure but provides imaging guidance for percutaneous endovascular therapies DIFFERENTIAL DIAGNOSIS Atherosclerosis Aneurysmal disease Degenerative process weakens arterial wall May involve CIAs &/or IIAs ± aortic involvement Dissection Iatrogenic dissection related to arterial catheterization Spontaneous iliac dissection is usually extension from thoracoabdominal aortic dissection Typical intimal flap separates true and false lumina Occlusive disease Infrarenal aortic occlusion or stenosis may extend distally to involve CIAs Isolated stenosis/occlusion of CIAs Usually involves CIA origins IIA origin stenoses are common Extensive collateralization is typically present Embolic Disease Acute or subacute symptoms Smooth abrupt occlusions, usually at bifurcations Often multifocal areas of occlusion Lack of collateral vessels Etiologies include proximal aneurysm, irregular atherosclerotic plaque, and cardiac arrhythmia Fibromuscular Dysplasia (FMD) EIAs are 3rd most common location Typically females, older than those with renal FMD Occlusive symptoms or spontaneous dissection Iliac Artery Endofibrosis Rare entity seen in young athletes Usually involves EIA Linked to repetitive hip joint motion, such as cycling 1216

Diagnostic Imaging Cardiovascular Fibrotic lesion often symptomatic only during exercise Traumatic Occlusion Common cause of iliac occlusion in young patients Blunt or penetrating pelvic trauma Catheterization-related (iatrogenic) injury e.g., dissection, hematoma, perforation, rupture P.16:18

Vasculitis More frequent in younger patients Aortic involvement in Takayasu arteritis may extend from aortic root to include CIAs Iliac artery pseudoaneurysms in Behçet disease PATHOLOGY General Features Etiology Peripheral artery disease (PAD) Occlusive disease due to atherosclerotic plaques From smooth muscle proliferation, extracellular lipid/collagen deposition, and inflammation Intraluminal plaque causes stenosis/occlusion Risk factors for atherosclerotic vascular disease Family history Diabetes Hypercholesterolemia Smoking Most common etiology in older patients Trauma, vasculitis, dissection, tumor encasement Staging, Grading, & Classification TransAtlantic Inter-Society Consensus (TASC) II: Comprehensive PAD management document; classifies anatomic lesions, makes treatment recommendations TASC II classification of aortoiliac lesions Type A lesion Unilateral/bilateral CIA stenoses Unilateral/bilateral single short (≤ 3 cm) EIA stenoses Type B lesion Short (≤ 3 cm) infrarenal aortic stenosis Unilateral CIA occlusion Single/multiple EIA stenoses totaling 3-10 cm, involving CFA Unilateral EIA occlusion not involving origins of IIAs or CFAs type C lesion Bilateral CIA occlusions Bilateral EIA stenoses 3-10 cm long; stenoses do not extend into CFAs Unilateral EIA stenosis extending into CFA Unilateral EIA occlusion involving IIA &/or CFA origins Heavily calcified unilateral EIA occlusion ± IIA/CFA origin involvement Type D lesion Infrarenal aortoiliac occlusion Diffuse disease of aorta and both iliac arteries Diffuse multiple stenoses unilaterally involving CIA and EIA plus CFA Unilateral combined occlusions of CIA and EIA Bilateral EIA occlusions CLINICAL ISSUES Presentation Most common signs/symptoms Intermittent claudication Exercise-related pain or muscle cramping that worsens with activity and subsides after rest Graded by distance patient is able to walk Location of pain may indicate level of obstruction 1217

Diagnostic Imaging Cardiovascular Iliac artery occlusive disease typically causes buttock and thigh claudication Symptoms vary with extent of arterial collaterals Other signs/symptoms Impotence Diseased IIA and internal pudendal arteries Assessment of lower extremity arterial insufficiency Focused history and physical examination Should include evaluation of arterial pulses Noninvasive arterial examination (e.g., PVR, ABI) If strong clinical evidence of pelvic arterial disease or abnormal noninvasive arterial examination Use CTA or MRA to confirm localized iliac disease If uncertain extent of disease, based on clinical findings, or evidence of multilevel occlusive disease Comprehensive assessment of lower extremity arteries is required; should include PVR, ABI Supplement noninvasive arterial examination with CTA/MRA if appropriate Can proceed to catheter angiography if indicated Demographics Epidemiology Atherosclerotic obstruction M>>F Incidence increases with age 45-54 years: 3%; 55-64 years: 6% Treatment TASC II categories: Treatment recommendations Type A: Endovascular procedures recommended Should be first-line treatment Type B: Endovascular procedures recommended Unless concurrent surgery for adjacent lesions Type C: Open revascularization recommended Endovascular procedures recommended only if potential for poor healing after open surgery Type D: Endovascular procedures not recommended Endovascular treatment options Angioplasty &/or stenting Surgical treatment options Surgical bypass or endarterectomy DIAGNOSTIC CHECKLIST Consider Endovascular therapy as first-line treatment Slightly poorer long-term patency vs. surgical bypass SELECTED REFERENCES 1. Dattilo PB et al: Clinical outcomes with contemporary endovascular therapy of iliac artery occlusive disease. Catheter Cardiovasc Interv. 80(4):644-54, 2012 2. Rastogi N et al: Symptomatic fibromuscular dysplasia of the external iliac artery. Ann Vasc Surg. 26(4):574, 2012 3. Ichihashi S et al: Long-term outcomes for systematic primary stent placement in complex iliac artery occlusive disease classified according to Trans-Atlantic Inter-Society Consensus (TASC)-II. J Vasc Surg. 53(4):992-9, 2011 4. Met R et al: Diagnostic performance of computed tomography angiography in peripheral arterial disease: a systematic review and meta-analysis. JAMA. 301(4):415-24, 2009 P.16:19

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(Left) 3D CTA reconstruction in a patient with left thigh claudication and an absent left femoral pulse shows occlusion of the left external iliac artery, with common femoral artery reconstitution via collaterals . (Right) Pelvic DSA via a catheter introduced from right common femoral arterial access confirms the left external iliac artery occlusion and common femoral artery reconstitution. The DSA was obtained in preparation for endovascular revascularization of the chronic total occlusion.

(Left) The occlusion was crossed with a catheter-guidewire combination, and (A) an angioplasty balloon was initially used to treat the recanalized segment. (B) Postangioplasty DSA shows restored patency but a very irregular lumen . Typically, endovascular treatment of iliac artery occlusions requires stenting. (Right) (C) DSA after stenting shows a widely patent left external iliac artery. (D) CT reconstruction shows that the stent originates at the iliac bifurcation & ends above the common femoral artery.

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(Left) FMD is an uncommon but known cause of lower extremity claudication and is reported in the external iliac arteries of 5% of patients with renal or carotid FMD. Coronal CTA of the external iliac artery (A) anteriorly and (B) more posteriorly shows the characteristic “string of beads” appearance . (Right) DSA confirms FMD of both external iliac arteries. The beaded appearance of the affected arterial segment is apparent in the right external iliac artery , and subtle changes are also evident on the left .

Iliac Artery Aneurysmal Disease > Table of Contents > Section 16 - Peripheral Vasculature > Vasculature of the Trunk > Iliac Artery Aneurysmal Disease Iliac Artery Aneurysmal Disease Suvranu Ganguli, MD Key Facts Terminology Iliac artery aneurysm: Focal or diffuse dilatation > 1.5× normal respective iliac artery diameter Regarded as aneurysmal if ≥ 25 mm in diameter Imaging Fusiform or saccular; may be continuous with abdominal aortic aneurysm (most common) or isolated Preoperative internal iliac artery coil embolization prior to endovascular aneurysm repair (EVAR) if stent graft is to extend beyond iliac bifurcation May serve as primary treatment for internal iliac artery aneurysm Prevents retrograde perfusion of aneurysm sac following EVAR Risk of buttock claudication and impotence with internal iliac artery embolization Clinical Issues Most common incidental finding during noninvasive imaging: > 65% are asymptomatic Iliac artery aneurysms are seen in 10-20% of patients with abdominal aortic aneurysms 40% of symptomatic patients present with rupture, which leads to rapid death if untreated Mortality rates after rupture and emergency treatment are as high as 33% Risk of rupture increases with aneurysm size Repair is recommended for aneurysm > 3 cm in diameter Occasionally may spontaneously thrombose or cause distal embolization Conventional treatment is open surgery Role of EVAR with stent grafts &/or coil embolization is increasing

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(Left) Anterior 3D CTA shows a saccular aneurysm of the left common iliac artery. An aneurysm of the right common iliac artery has thrombosed, occluding the right common iliac artery , with reconstitution of the right external iliac artery through prominent collaterals. (Right) Axial CTA depicts a fusiform aneurysm containing a mural thrombus of the right common iliac artery and extending to the iliac bifurcation . Note normal contralateral internal and external iliac arteries.

(Left) Anterior CTA 3D reconstruction shows a fusiform aneurysm of the right common iliac artery and an aortic aneurysm . (Right) Anteroposterior DSA in the same patient after successful stent graft placement to treat both aneurysms shows coil embolization of the right internal iliac artery to prevent backflow into the aneurysm, extension of the right limb to the external iliac artery to exclude the iliac aneurysm, and preserved patency of the left internal iliac artery to supply the pelvis. P.16:21

TERMINOLOGY Definitions Iliac artery aneurysm: Focal or diffuse dilatation > 1.5× normal respective iliac artery diameter Regarded as aneurysmal if ≥ 25 mm in diameter Fusiform aneurysm: Diffusely and circumferentially involves lengthy arterial segment Saccular aneurysm: Focally involves arterial segment; appears as focal outpouching or bulge True aneurysm contains all 3 arterial wall layers Most commonly due to atherosclerosis False aneurysm (pseudoaneurysm) does not contain all 3 layers of arterial wall Focal or diffuse disruption of arterial wall Causes include iatrogenic or penetrating trauma, contained rupture, vascular infection (mycotic) 1221

Diagnostic Imaging Cardiovascular IMAGING General Features Best diagnostic clue Focal or diffuse iliac arterial enlargement Mural calcification may define margins Location Aneurysms involve common and internal iliac arteries > external iliac arteries Common iliac arteries extend from aortic bifurcation to bifurcation into internal and external iliac arteries Internal iliac arteries extend from common iliac artery bifurcation to terminate as bifurcation into anterior and posterior divisions External iliac arteries extend from common iliac bifurcation to terminate at inguinal ligament Size Enlargement > 1.5× normal iliac artery diameter If diameter exceeds 25 mm, considered aneurysm Morphology May be fusiform or saccular May be continuous with abdominal aortic aneurysm (AAA) (most common) or may be isolated Imaging Recommendations Best imaging tool Noninvasive imaging modalities CECT and CTA with 3D reconstruction MR/MRA: Gated SE T1, enhanced 3D GE Angiography with calibrated catheter may allow for both diagnosis and therapy CT Findings CECT with CTA provides excellent information for surveillance &/or treatment planning Maximum aneurysm diameter and length Aneurysm relationship to aortic and iliac artery bifurcations Anatomy of access arteries (common femoral, external iliac) if endovascular aneurysm repair (EVAR) is planned Diameter, tortuosity, stenoses, heavy calcification Presence or absence of adequate proximal/distal “landing zones” for EVAR graft fixation Evaluation for endoleak following EVAR MR Findings T1WI High signal intensity lumen Relatively low, heterogeneous signal intensity mural thrombus MRA Useful for evaluation of pre-EVAR anatomy; similar findings to CTA Calcification in aneurysm walls are difficult to evaluate Artifact from stents or embolization coils limits evaluation of stented/coiled vessels Angiographic Findings Preoperative angiography is usually unnecessary in majority of patients Shows intraluminal diameter and relationship of aneurysm to aortic and iliac bifurcations Inaccurate for aneurysm size because of mural thrombus Calibrated catheter is used for length measurements Preoperative internal iliac artery coil embolization prior to EVAR if stent graft extends beyond iliac bifurcation Prevents retrograde perfusion of aneurysm sac following EVAR May serve as primary treatment for internal iliac artery aneurysm Risk of buttock claudication and impotence with internal iliac artery embolization Ultrasonographic Findings Good modality for monitoring smaller AAA Not reliable for detection or follow-up of iliac artery aneurysms Inadequate information for treatment planning Shows luminal diameter, intraluminal thrombus, aneurysm diameter Not reliable for measuring length of aneurysms May be limited by body habitus and bowel gas DIFFERENTIAL DIAGNOSIS Atherosclerotic Stenosis or Occlusion 1222

Diagnostic Imaging Cardiovascular Luminal narrowing secondary to laminar thrombus in aneurysm may mimic stenosis Thrombosed aneurysm may mimic atherosclerotic occlusion Distal aortic occlusive disease usually extends to involve common iliac arteries Severe stenosis: May have poststenotic dilatation in adjacent arterial segment Iliac Artery Dissection Most common etiology: Extension from thoracoabdominal or abdominal aortic dissection Iliac &/or femoral artery extension in 50% of abdominal aortic dissections Intimal flap divides into true and false lumina True lumen is circumferentially lined with intima False lumen lies outside of intima May thrombose &/or compress true lumen Anastomotic Pseudoaneurysm Associated with AAA repair in 0.5-5% P.16:22

Due to suture line disruption, graft or arterial wall failure, infection, technical error Repair if symptomatic (e.g., rupture, thrombosis, embolus) or if diameter is 2× aortic graft diameter Fibromuscular Dysplasia (FMD) Iliac arteries: 3rd most common location for FMD Patient is typically female; older age than in renal artery FMD May have occlusive symptoms &/or occasional spontaneous dissection PATHOLOGY General Features Etiology Most common cause is atherosclerosis Other causes Chronic dissection Inflammation (unknown etiology; younger patient; enhancing circumferential rim of tissue) Vasculitis (e.g., Behçet disease, Takayasu arteritis) Infection (mycotic aneurysm) Connective tissue disorders (e.g., Ehlers-Danlos, Marfan syndrome) Anastomotic or traumatic pseudoaneurysm CLINICAL ISSUES Presentation Most common signs/symptoms Incidental findings during noninvasive imaging > 65% of cases are asymptomatic When symptomatic, similar to AAA Abdominal pain in 32% of symptomatic patients Neurologic, genitourologic, gastrointestinal symptoms due to external compression Occasional groin, hip, or buttock pain Other signs/symptoms 40% of symptomatic patients present with rupture, which leads to rapid death if untreated Leads to rapid death if untreated Demographics Age Commonly occurs in elderly men, similar to AAA Gender M>F Epidemiology Isolated iliac artery aneurysms are rare (0.03% incidence) Represent 2-7% of all intraabdominal aneurysms Iliac artery aneurysms are seen in 10-20% of patients with AAAs Natural History & Prognosis Reported overall death rate of 31% for isolated iliac artery aneurysms Progressive expansion with eventual rupture is most common Rupture is associated with up to 80% mortality risk Risk of rupture increases with aneurysm size 1223

Diagnostic Imaging Cardiovascular Repair is recommended for aneurysm > 3 cm in diameter Occasionally may spontaneously thrombose or cause distal embolization Treatment Conventional treatment: Open surgery Appropriate for iliac artery aneurysms with compressive symptoms (neurologic or urologic) Endovascular treatment cannot rapidly reduce aneurysm size Mortality rates after rupture and emergency treatment are as high as 33% EVAR with stent grafts &/or coil embolization Long-term results of EVAR are still unknown, but its role is increasing Specific strategy for treatment depends on aneurysm location and morphology Aortoiliac EVAR is necessary if common iliac artery origin is aneurysmal Proximal “landing zone” in aorta is required for graft seal and endoleak prevention Common iliac artery aneurysm involving iliac bifurcation requires graft extension into external iliac artery Requires concurrent embolization of internal iliac artery to prevent retrograde endoleak Regular post-procedure follow-up imaging is necessary to document aneurysm thrombosis, reduction of aneurysm sac size, and lack of endoleak Excellent long-term outcomes are reported with regard to delayed rupture or death Few secondary interventions are required SELECTED REFERENCES 1. Fossaceca R et al: Long-term efficacy of endovascular treatment of isolated iliac artery aneurysms. Radiol Med. 118(1):62-73, 2013 2. Parlani G et al: Long-term results of iliac aneurysm repair with iliac branched endograft: a 5-year experience on 100 consecutive cases. Eur J Vasc Endovasc Surg. 43(3):287-92, 2012 3. Melas N et al: Isolated common iliac artery aneurysms: a revised classification to assist endovascular repair. J Endovasc Ther. 18(5):697-715, 2011 4. Chemelli A et al: Endovascular repair of isolated iliac artery aneurysms. J Endovasc Ther. 17(4):492-503, 2010 5. Dorigo W et al: The Treatment of Isolated Iliac Artery Aneurysm in Patients with Non-aneurysmal Aorta. Eur J Vasc Endovasc Surg. 2008 6. Gabrielli R et al: Classic and endovascular surgical management of isolated iliac artery aneurysms. Minerva Cardioangiol. 55(2):133-48, 2007 7. Laganà D et al: Endovascular treatment of isolated iliac artery aneurysms: 2-year follow-up. Radiol Med (Torino). 112(6):826-36, 2007 8. Mofidi R et al: Endovascular repair of a ruptured mycotic aneurysm of the common iliac artery. Cardiovasc Intervent Radiol. 30(5):1029-32, 2007 9. Pitoulias GA et al: Isolated iliac artery aneurysms: endovascular versus open elective repair. J Vasc Surg. 46(4):64854, 2007 10. Stroumpouli E et al: The endovascular management of iliac artery aneurysms. Cardiovasc Intervent Radiol. 30(6):1099-104, 2007 11. van Kelckhoven BJ et al: Ruptured internal iliac artery aneurysm: staged emergency endovascular treatment in the interventional radiology suite. Cardiovasc Intervent Radiol. 30(4):774-7, 2007 P.16:23

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(Left) Axial CTA depicts a large aneurysm of the right common iliac artery with small mural calcification and absence of mural thrombus. Note the left internal and external iliac arteries immediately distal to the iliac bifurcation on the opposite side. (Right) Anteroposterior CTA 3D reconstruction of the same patient shows the relationship of the isolated fusiform aneurysm of the right common iliac artery to the aortic and iliac bifurcations.

(Left) Anteroposterior DSA performed in the same patient shows successful coil embolization of the right internal iliac artery to prevent backflow into the large right common iliac artery aneurysm after stent graft placement. (Right) Anteroposterior DSA performed after stent graft placement in the same patient, extending from the proximal right common iliac artery to the distal right external iliac artery, depicts successful exclusion of the right common iliac artery aneurysm.

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(Left) Anteroposterior DSA performed prior to endovascular treatment shows a large saccular aneurysm of the right internal iliac artery and smaller fusiform aneurysms of the right common iliac , left common iliac , and left internal iliac arteries. (Right) Coronal oblique CTA reformat in the same patient post-treatment shows partially visualized coil embolization of the distal internal iliac artery. Stent graft placement successfully excludes and thromboses the right internal iliac artery aneurysm .

Lower Extremity Vasculature Lower Extremity Aneurysms > Table of Contents > Section 16 - Peripheral Vasculature > Lower Extremity Vasculature > Lower Extremity Aneurysms Lower Extremity Aneurysms T. Gregory Walker, MD, FSIR Key Facts Terminology Aneurysm: Focal enlargement of vascular lumen Due to intrinsic abnormality of arterial wall Pseudoaneurysm: Contained leakage of blood from artery into adjacent soft tissues Due to disruption of arterial wall integrity Persistent communication between artery and pseudoaneurysm cavity Imaging Aneurysm frequency by location Popliteal artery is most common lower extremity location (70% of all peripheral aneurysms) Common femoral artery is 2nd most common location for lower extremity aneurysm Profunda femoral artery aneurysms are rare (0.5% of all peripheral aneurysms) Imaging findings DSA: Saccular or fusiform arterial enlargement; occasional normal diameter if significant thrombus CTA: Similar findings to DSA; also provides 3D arterial and perivascular anatomy MRA: Similar findings to DSA Clinical Issues Thromboembolism, often with irreversible ischemia, is most serious sequela of lower extremity aneurysms Incidence highly depends on aneurysm diameter; most complications occur with diameters > 2 cm 35% incidence of thromboembolic complications; 25% amputation rate for untreated popliteal artery aneurysms (PAAs) Emergent intervention is often necessary Diagnostic Checklist Consider thrombosed PAA with popliteal artery occlusion, especially if other aneurysms are present

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(Left) Axial color Doppler US of the popliteal fossa in a man who presented with acute left foot ischemia shows a round mass containing extensive echogenic material along with an eccentric channel of mixed vascular signal. Findings are consistent with a popliteal artery aneurysm (PAA) containing extensive laminar thrombus. (Right) Axial CECT of both thighs above the popliteal fossae shows bilateral PAAs . Each contains extensive laminar thrombus surrounding a small patent lumen , as seen on the left-side US image.

(Left) CTA reconstruction shows the morphology of the PAAs . These aneurysms are usually fusiform and are bilateral in 60-70% of cases. Thromboembolism, often with irreversible limb ischemia, is the most serious sequela of these aneurysms, whereas rupture rarely occurs. (Right) (A) DSA shows the tortuous aneurysm lumen . PAAs > 2 cm in diameter should be repaired as there is a 35% incidence of thromboembolic complications and a 25% amputation rate if untreated. (B) Increasingly, PAAs are treated with covered stents . P.16:25

TERMINOLOGY Definitions Aneurysm: Focal enlargement of vascular lumen Due to intrinsic abnormality of arterial wall All 3 layers of arterial wall remain intact Also known as true aneurysm Pseudoaneurysm: Contained leakage of blood from artery into adjacent soft tissues Due to disruption of arterial wall integrity Persistent communication between artery and pseudoaneurysm cavity Does not contain normal arterial wall components 1227

Diagnostic Imaging Cardiovascular Also known as false aneurysm IMAGING General Features Location Popliteal artery is most common location for lower extremity aneurysm Accounts for > 70% of all peripheral aneurysms Higher incidence in patients with abdominal aortic aneurysms (AAAs); 6-12% occurrence 60-70% of popliteal artery aneurysms (PAAs) are bilateral If bilateral PAA is present, 75% also have AAA Common femoral artery (CFA) is 2nd most common location for lower extremity aneurysm CFA aneurysms are associated with AAA and PAA 1/3 of patients with CFA aneurysms have PAA Must be distinguished from pseudoaneurysms, which frequently occur in femoral location Profunda femoral artery aneurysms are rare (0.5% of all peripheral aneurysms) High complication rate at presentation Significant incidence of other aneurysms Superficial femoral artery aneurysms are rare Tibial artery aneurysms are very infrequent Usually are pseudoaneurysms associated with trauma or iatrogenic injury such as catheterization Ultrasonographic Findings Grayscale ultrasound Fusiform or saccular arterial enlargement, often with laminar thrombus within Color Doppler Pseudoaneurysm appears as rounded vascular structure of mixed biphasic signal Appearance described as yin-yang sign Communicating tract (neck) with underlying artery Angiographic Findings Saccular or tortuous fusiform arterial enlargement Occasional normal diameter if significant thrombus Clue to presence of aneurysm: Absent side branches Always consider thrombosed aneurysm with popliteal artery occlusion, especially if other aneurysms present Shows status of arteries distal to aneurysm Embolization is common and determines outcome CT Findings CTA has similar findings to DSA Also provides 3D arterial and perivascular anatomy Demonstrates thrombus and true luminal diameter MR Findings MRA has similar findings to DSA Demonstrates thrombus and true luminal diameter, as well as perivascular anatomy DIFFERENTIAL DIAGNOSIS Atherosclerotic Occlusive Disease Chronic claudication symptoms, often bilateral Involvement of multiple arterial levels or segments Stenoses or occlusions Acute symptoms may mimic distal embolization from, or acute occlusion of, peripheral aneurysm Well-developed collateral circulation Cystic Adventitial Disease Sudden onset of claudication in young patient Unilateral scimitar-shaped stenosis of popliteal artery caused by cystic mucinous fluid within adventitia US or MR shows cysts adjacent to arterial stenosis Rarely causes arterial thrombosis or distal embolization Ehlers-Danlos Syndrome Rare inherited disorder with defect in collagen synthesis; multiple types within classification Autosomal dominant defect in type 3 1228

Diagnostic Imaging Cardiovascular Collagen synthesis affects vascular system Spontaneous dissection, aneurysms, and vessel rupture are most common vascular manifestations 70% angiography complication rate Due to abnormal arterial wall Embolus Acute symptoms similar to distal embolization from, or acute occlusion of, peripheral aneurysm Intraluminal filling defect(s) on CTA or DSA Meniscus at margin of occlusion on CTA or DSA Poorly formed collaterals Extravascular Collection Hematoma, seroma, or lymphocele can produce palpable mass adjacent to artery Close proximity of collection to artery may result in transmitted pulsation and thus mimic aneurysm, pseudoaneurysm, or arteriovenous fistula (AVF) Neoplasm Inguinal adenopathy may produce palpable mass May mimic hematoma, thrombosed aneurysm/pseudoaneurysm Soft tissue neoplasms may mimic aneurysms if highly vascular, e.g., hemangioma Popliteal Artery Entrapment Aberrant relationship of artery to gastrocnemius muscle with resultant arterial compression Repetitive trauma eventually leads to development of adventitial thickening and fibrosis May result in stenosis, thrombosis, or aneurysm Clinically causes claudication, chronic leg ischemia Pseudoaneurysm Disruption in arterial wall continuity Etiologies include inflammation, trauma, or iatrogenesis Higher rupture risk than true aneurysm of same size P.16:26

Iatrogenic pseudoaneurysm is usually associated with catheterization site or vascular surgical anastomosis Can treat iatrogenic postcatheterization pseudoaneurysm with thrombin injection (preferred) or with ultrasound compression Vascular surgical anastomotic pseudoaneurysm requires surgical revision Trauma Repetitive, blunt, penetrating, or iatrogenic trauma may cause aneurysm, AVF, or pseudoaneurysm Hematoma may mimic pseudoaneurysm, particularly at anastomosis or catheterization site PATHOLOGY General Features Etiology Pathogenesis of peripheral arterial aneurysms is usually due to same mechanisms involved in AAA Degenerative process affecting elastin fibers and inflammatory infiltrative changes affecting arterial media and adventitia Proteolytic enzymatic degradation of collagen and elastin in arterial wall Popliteal artery aneurysms can also result from popliteal artery entrapment syndrome Other etiologies for peripheral aneurysms Behçet disease Ehlers-Danlos syndrome Iatrogenic (catheterization, surgical bypass, intervention) Infection (mycotic aneurysm) Marfan syndrome Trauma Associated abnormalities High association of peripheral aneurysms with AAA > 70% of patients with peripheral aneurysms also have AAA Popliteal aneurysms are associated with arteriomegaly CLINICAL ISSUES Presentation Most common signs/symptoms 1229

Diagnostic Imaging Cardiovascular Common femoral artery aneurysms Asymptomatic or pulsatile groin swelling Occasional compression of femoral vein (edema) or nerve (pain, paresthesia) Rarely, complications of thrombosis, distal embolization, or rupture Profunda femoral artery aneurysms Higher rupture rate than other extremity aneurysms Superficial femoral artery aneurysms Present with limb-threatening ischemia or rupture Popliteal artery aneurysms Thromboembolic symptoms Occurrence related to aneurysm diameter as larger aneurysms contain more thrombus Limb ischemia is presenting symptom in > 50% 1/3 are asymptomatic at time of diagnosis, but 50% develop distal ischemia within 5 years Tibial artery aneurysms Usually asymptomatic; occasional calf swelling Natural History & Prognosis Thromboembolism, often with irreversible ischemia, is most serious sequela of lower extremity aneurysms Incidence is highly dependent on aneurysm diameter Most complications occur with diameters > 2 cm 35% incidence of thromboembolic complications and 25% amputation rate for untreated PAAs Complication rate increases to 74% after 5 years Emergent intervention is often necessary Rupture is much less common than with pseudoaneurysms or aortic and iliac artery aneurysms Treatment Iatrogenic access-related pseudoaneurysms should be treated with thrombin injection if appropriate Some pseudoaneurysms require primary surgical repair All mycotic pseudoaneurysms Pseudoaneurysms with excessively wide necks Pseudoaneurysms causing mass effect (e.g., claudication, neuropathy, critical limb ischemia) Surgical resection and bypass is accepted standard treatment for lower extremity true aneurysms Treatment results are far superior in asymptomatic patients (85-100% patency at 5 years) than in symptomatic patients (54-72% patency) High mortality rate (5-8%) with emergency treatment Endovascular repair of lower extremity arterial aneurysms is now performed with increasing frequency Endovascular treatment lacks long-term follow-up Encouraging early mid-term results of elective endovascular PAA repair 12-month primary patency rates: 60-87% 24-month secondary patency rates: 78-98% DIAGNOSTIC CHECKLIST Consider Thrombosed PAA with popliteal artery occlusion, especially if other aneurysms are present elsewhere Image Interpretation Pearls Angiography may underestimate size of aneurysm if there is significant intralaminar thrombus SELECTED REFERENCES 1. Garg K et al: Outcome of endovascular repair of popliteal artery aneurysm using the Viabahn endoprosthesis. J Vasc Surg. 55(6):1647-53, 2012 2. Pulli R et al: Comparison of early and midterm results of open and endovascular treatment of popliteal artery aneurysms. Ann Vasc Surg. 26(6):809-18, 2012 3. Rico JV et al: Urgent endovascular treatment of a ruptured tibioperoneal pseudoaneurysm in Behçet's disease. Ann Vasc Surg. 25(3):385, 2011 4. Moore RD et al: Open versus endovascular repair of popliteal artery aneurysms. J Vasc Surg. 51(1):271-6, 2010 5. Davies RS et al: Long-term results of surgical repair of popliteal artery aneurysm. Eur J Vasc Endovasc Surg. 34(6):714-8, 2007 6. Corriere MA et al: True and false aneurysms of the femoral artery. Semin Vasc Surg. 18(4):216-23, 2005 7. Edgerton JR et al: Obliteration of femoral artery pseudoaneurysm by thrombin injection. Ann Thorac Surg. 74(4):S1413-5, 2002 8. Marmorale A et al: Aneurysms of the infrapopliteal arteries. J R Coll Surg Edinb. 40(5):324-6, 1995 P.16:27

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(Left) Angiography shows a large pseudoaneurysm arising from a branch of the right profunda femoral artery. This was a posttraumatic pseudoaneurysm that occurred as a result of a right hip fracture. It was successfully treated with transcatheter embolization. (Right) Lateral angiography of the calf shows a trilobed aneurysm or pseudoaneurysm of the tibioperoneal arteries, arising from the popliteal artery . There is associated erosion of the adjacent bone, which is an unusual finding.

(Left) Sagittal color Doppler US of the right groin in a man with a pulsatile mass after transfemoral access for DSA shows a round mass with mixed signal in a yin-yang pattern . A narrow neck with a biphasic arterial waveform connects to the underlying femoral artery. The findings are typical of an iatrogenic access-related pseudoaneurysm. (Right) Color Doppler US during thrombin injection shows a needle tip within the pseudoaneurysm and no flow. This indicates thrombosis and thus successful treatment.

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(Left) Pseudoaneurysms may develop at vascular surgical bypass anastomoses, as in this patient who presented with pulsatile inguinal masses and remote history of bypass surgery for aortoiliac occlusive disease. Axial CECT shows large bilateral common femoral artery pseudoaneurysms . (Right) Coronal CTA shows a patent aortobifemoral bypass graft . Large pseudoaneurysms are well seen at the distal anastomoses to the common femoral arteries. The CFA is the most frequent location for pseudoaneurysms.

Acute Lower Extremity Ischemia > Table of Contents > Section 16 - Peripheral Vasculature > Lower Extremity Vasculature > Acute Lower Extremity Ischemia Acute Lower Extremity Ischemia Suvranu Ganguli, MD Key Facts Terminology Sudden decrease in tissue perfusion of lower extremity; emergency as limb viability is threatened Imaging DSA: Gold standard for diagnosing acute occlusion CTA: Abrupt occlusion ± filling defect; similar findings to angiography Sensitivities and specificities: 88% and 95% for US; 92-100% and 93-100% for CTA; 97% and 96% for CE-MRA (using angiography as gold standard) Macroemboli usually lodge in distal femoral or popliteal artery Total occlusion with presence of meniscus sign In microembolization syndromes, shaggy, ulcerated, atherosclerotic disease is found in proximal vessels Thrombotic occlusion: Significant atherosclerotic disease elsewhere Abrupt termination of vessel ± collateral formation, no meniscus Diagnostic catheter angiography may be combined with intervention (e.g., thrombolysis) Pathology Thrombosis in 85% and embolism in 15% of patients Source of emboli: Cardiac (most common), aneurysm, atherosclerotic plaque, upstream critical stenosis Thrombosis is usually superimposed on chronic atherosclerotic disease Multifactorial acute arterial occlusion consequences Tibial compartment pressure, degree of collateral circulation, reperfusion injury, occlusion duration Clinical Issues Initial anticoagulation followed by imaging Typically requires angiography if intervention is planned

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(Left) CTA coronal reconstruction reveals a filling defect consistent with an embolus within the proximal right superficial femoral artery , which has lodged at the bifurcation of the right femoral artery into the superficial and profunda branches. (Right) Axial CTA shows focal enlargement of the right popliteal artery with a central filling defect indicating an embolus that has lodged in this location. The left popliteal artery appears normal.

(Left) Post-contrast axial T1 GRE shows a central occlusive filling defect in a dilated right external iliac artery, typical of an acute arterial embolus . The left external iliac artery is normal. (Right) Anteroposterior MIP image from a high-resolution CE-MRA shows multifocal stenoses and irregularities of the left tibioperoneal trunk and proximal anterior and posterior tibial arteries due to multiple emboli. P.16:29

TERMINOLOGY Definitions Sudden decrease in tissue perfusion of lower extremity Constitutes emergency as limb viability is threatened IMAGING General Features Best diagnostic clue Abrupt termination of distal femoral, popliteal, or trifurcation arteries Location Peripheral arterial bifurcations Angiographic Findings DSA: Gold standard for diagnosing acute occlusion 1233

Diagnostic Imaging Cardiovascular Embolic occlusion Macroemboli usually lodge in distal femoral or popliteal artery Total occlusion with presence of meniscus sign indicating embolus Absence of collaterals In microembolization syndromes, shaggy, ulcerated atherosclerotic disease is found in proximal vessels Thrombotic occlusion Significant atherosclerotic disease elsewhere Abrupt termination of vessel ± collateral formation Diagnostic catheter angiography may be combined with intervention (e.g., thrombolysis) Can diagnose and treat significant stenoses or occlusions MR Findings MRA Embolus: Occlusive low-signal filling defect with meniscus sign; similar to angiography Thrombotic occlusion: Low-signal focal filling defect; no meniscus sign T1 post-contrast GRE Thromboemboli are seen as low-signal intraarterial filling defects Arterial wall is better evaluated than on CE-MRA Thrombosed popliteal artery aneurysms are better demonstrated Low-signal mural thrombus in aneurysm Peripheral enhancement of perigraft collections CT Findings CTA Abrupt occlusion ± filling defect Similar findings to angiography Ultrasonographic Findings Grayscale ultrasound Vessel wall thickening Luminal narrowing from plaque Echogenic luminal filling defect Intimal flap Aneurysm with thrombus or thrombosis Pulsed Doppler Elevated peak systolic velocity indicates high-grade stenosis Absent, dampened, or monophasic distal waveform suggests more proximal occlusion Ankle-brachial indices Normal: > 0.97 (usually up to 1.10) Claudication: 0.40-0.80 Rest pain: 0.20-0.40 Ulceration, gangrene: 0.10-0.40 Acute ischemia: Usually < 0.10 Imaging Recommendations Best imaging tool Catheter angiography CE-MRA or CTA Sensitivities and specificities: 88% and 95% for US; 92-100% and 93-100% for CTA; 97% and 96% for CE-MRA (using angiography as gold standard) Protocol advice Multislice CTA: Bolus tracking; lower abdominal aorta as region of interest; 120-140 mL contrast at 3-4 mL/s; 30-40 mL of saline chaser to keep bolus compact 0.6, 0.75, or 1 mm thin-collimation volumetric acquisition with axial reconstructions at 0.75-1 mm thickness with 0.5 mm overlap Coronal and sagittal multiplanar reformats Volume-rendered images optional MRA: 3D high-resolution CE-MRA with bolus timing Double-dose contrast with dual injection technique on moving-table MR scanner 1st injection for calves (1st station, 2 passes); 2nd injection for combined aortoiliac (2nd station, 1 pass) and thighs (3rd station, 2 passes) Nonenhanced mask images for subtraction to increase vessel to background contrast 1234

Diagnostic Imaging Cardiovascular Overlapping MIP and rotational MIP post processing Immediate axial post T1 GRE to assess arterial wall, veins, bypass grafts, luminal thrombus, aneurysm Pre-contrast targeted T2 or STIR in suspected cystic lesions and osteomyelitis DIFFERENTIAL DIAGNOSIS Embolization Macroembolization Cardiac source (left atrium or left ventricular thrombus) Proximal atherosclerotic plaque Abdominal or thoracic aortic aneurysm Microembolization Cholesterol embolization from prior catheterization Blue toe syndrome: Subacute or chronic microembolization Acute Thrombosis Thrombosis due to preexisting arterial stenosis or obstruction Arterial bypass graft thrombosis Thrombosis at site of aneurysm Traumatic Arterial Injury Associated bone fractures, possible extravasation May be iatrogenic (arterial catheterization) Vasculitis Young patient Abnormal narrowing or occluded digital arteries P.16:30

Popliteal Entrapment Syndrome Young individuals, bilateral in 60-70% Medial deviation of popliteal artery, which courses under medial head of gastrocnemius Thrombosis or occlusion with poor distal runoff Stress (plantar flexion) position increases arterial angulation and deviation Popliteal Artery Aneurysm Unilateral trifurcation disease; thromboemboli or decreased runoff Peripheral thrombus, rim calcification Symptoms are typically related to distal embolization or acute thrombosis Rupture is least common complication PATHOLOGY General Features Etiology Acute embolic or thrombotic arterial occlusion Thrombosis in 85% and embolism in 15% of patients; majority have atherosclerotic disease Emboli source: Cardiac (most common), aneurysm, atherosclerotic plaque, upstream critical stenosis Thrombosis is usually superimposed on chronic atherosclerotic disease Typically secondary to atherosclerotic stenosis in native vessel Anastomotic stenosis or distal progression of disease in bypass graft Bypass graft can develop de novo thrombosis Thrombosed aneurysm (popliteal) Acute arterial occlusion consequences are multifactorial Tibial compartment pressure, degree of collateral circulation, reperfusion injury Occlusion duration; presence of oxygen-free radicals Cellular edema causing microvascular obstruction with no reflow phenomenon Staging, Grading, & Classification Society of Vascular Surgery/International Society of Cardiovascular Surgery classification system (Rutherford criteria) for acute limb ischemia Class 1: Viable, nonthreatened extremity No rest pain, neurologic deficit, or compromised skin circulation Audible Doppler flow signals Class 2: Threatened viability; reversible ischemia, salvageable limb if arterial obstruction is relieved 2A: Limb is not immediately threatened 1235

Diagnostic Imaging Cardiovascular 2B: Severely threatened; urgent revascularization necessary for salvage Rest pain, mild neurologic deficits; Doppler arterial signals are absent; venous signals are present Class 3: Major, irreversible ischemic change; frequently requires major amputation Absent capillary or skin perfusion, muscle rigor, sensory loss, muscle paralysis Completely absent Doppler signals Microscopic Features Microscopic embolization From ulcerated plaques or aneurysms Cholesterol crystals, fibrin-platelet deposits, cellular thrombi CLINICAL ISSUES Presentation Most common signs/symptoms 5 Ps: Pain, pallor, paresthesia, pulselessness, paralysis Ankle pressure < 70 mm Hg in severe lower extremity ischemia Demographics Age Elderly Gender Severe ischemia is more common in women Natural History & Prognosis Limb loss, sepsis, or death Treatment Initial anticoagulation followed by imaging Typically, angiography if intervention is planned Thrombolytic therapy with transcatheter infusion Mechanical thrombectomy, thromboaspiration Thromboembolectomy, vascular bypass graft, amputation, surgical therapy DIAGNOSTIC CHECKLIST Consider Cardiac and aortic source of thromboemboli in patients with acute limb ischemia Rarely, paradoxical emboli from deep venous thrombosis via PFO or other shunt Image Interpretation Pearls Protruding aortic mural thrombus and floating intraluminal aortic thrombus are hypovascular; appear as irregular low-attenuation or signal on CTA/MRA Suspect acute thromboembolism in abrupt occlusion, occlusive filling defect, unilateral disease, meniscus sign, and absent collaterals SELECTED REFERENCES 1. Malcolm PN et al: Prospective studies show that magnetic resonance angiography has high sensitivity and specificity for clinically relevant arterial steno-occlusions in adults with peripheral arterial disease symptoms. Evid Based Med. 16(3):90-1, 2011 2. Elmahdy MF et al: Value of duplex scanning in differentiating embolic from thrombotic arterial occlusion in acute limb ischemia. Cardiovasc Revasc Med. 11(4):223-6, 2010 3. Huppertz A et al: Biphasic blood pool contrast agent-enhanced whole-body MR angiography for treatment planning in patients with significant arterial stenosis. Invest Radiol. 44(7):422-32, 2009 4. O'Connell JB et al: Proper evaluation and management of acute embolic versus thrombotic limb ischemia. Semin Vasc Surg. 22(1):10-6, 2009 5. Walker TG: Acute limb ischemia. Tech Vasc Interv Radiol. 12(2):117-29, 2009 6. Heijenbrok-Kal MH et al: Lower extremity arterial disease: multidetector CT angiography meta-analysis. Radiology. 245(2):433-9, 2007 P.16:31

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(Left) AP pelvic catheter angiography reveals a high-grade irregular stenosis of the left common iliac artery , caused by atherosclerotic plaque. The patient presented with acute left lower extremity ischemia. (Right) AP catheter angiography of the feet reveals occlusions of the distal left anterior tibial artery and the entire left posterior tibial artery . The patient's acute lower extremity ischemia is caused by microemboli from the upstream left common iliac lesion.

(Left) AP pelvic catheter angiography after balloon-mounted stent placement across the high-grade, irregular stenosis of the left common iliac artery shows resolution of the stenosis. The patient subsequently underwent catheter-directed thrombolysis of the left lower extremity. (Right) CTA 3D reconstruction shows acute thrombosis of the right popliteal artery . Small collateral arteries are identified, indicating an acute on chronic process.

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(Left) AP catheter angiography of the right lower extremity reveals the acute thrombosis of the right popliteal artery . Small collateral arteries are identified bypassing the occlusion, indicating acute thrombosis of a chronic atherosclerotic lesion. (Right) AP catheter angiography after revascularization of the right lower extremity using catheter-directed thrombolysis and stent placement across the target lesion shows restoration of flow to the right lower extremity.

Femoropopliteal Artery Occlusive Disease > Table of Contents > Section 16 - Peripheral Vasculature > Lower Extremity Vasculature > Femoropopliteal Artery Occlusive Disease Femoropopliteal Artery Occlusive Disease T. Gregory Walker, MD, FSIR Key Facts Terminology Femoropopliteal artery occlusive disease: Stenosis or occlusion of common femoral artery, superficial femoral artery, or popliteal artery Chronic total occlusion: Complete arterial obstruction lasting > 3 months; no luminal patency Imaging If history and physical examination suggest arterial disease, obtain noninvasive arterial examination If study shows evidence of occlusive disease, obtain CTA, MRA, or DSA to confirm and localize DSA is gold standard for vessel characterization Invasive procedure but provides imaging guidance for percutaneous endovascular therapies Pathology Peripheral artery disease Occlusive disease due to atherosclerotic plaques Most common etiology of occlusions (older patients) Trauma, vasculitis, emboli, tumor encasement Clinical Issues Most common signs and symptoms Intermittent claudication: Exercise-related pain or muscle cramping, worsening with activity and subsiding after rest Acute limb ischemia: May signal embolic occlusion Treatment Based on severity of ischemia for acute embolic or thrombotic occlusion: Severely ischemic limb is surgical emergency; consider thrombolysis and endovascular revascularization if limb well perfused Endovascular revascularization is now often considered primary treatment of choice for chronic occlusive disease Bypass surgery with reversed or in situ saphenous vein graft has long-term durability (gold standard)

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(Left) Color Doppler ultrasound of the proximal right superficial femoral artery (SFA) in a man with lower extremity claudication shows marked elevation of the peak systolic velocity, calculated at 387.8 cm/s and a monophasic arterial waveform when sampled in the intrastenotic segment. Findings are consistent with a severe SFA stenosis in the 76-99% range. (Right) MRA confirms a severe stenosis in the proximal right SFA as well as diffuse atherosclerotic disease more distally. Left SFA disease is also present.

(Left) Right leg DSA (same patient) shows (A) a severe stenosis in the proximal right SFA as well as the diffuse disease that was noted on the MRA study. (B) The popliteal artery is relatively disease free, and a 3-vessel infrapopliteal runoff is present. (Right) DSA after angioplasty of the right SFA stenosis (same patient) shows an irregular linear contrast focus paralleling the arterial lumen at the treatment zone. This is a frequent finding after angioplasty, representing dissection clefts within the expanded atheromatous lesion. P.16:33

TERMINOLOGY Definitions Femoropopliteal artery occlusive disease: Stenosis or occlusion of common femoral artery (CFA), superficial femoral artery (SFA), or popliteal artery Chronic total occlusion (CTO): Complete arterial obstruction lasting > 3 months; no luminal patency Typically densely organized with fibrous tissue May calcify; lesions often difficult to cross and treat IMAGING General Features Best diagnostic clue Arterial stenoses and occlusions 1239

Diagnostic Imaging Cardiovascular Often involve CFA bifurcation, distal SFA Segmental occlusions with distal reconstitution Well-developed collaterals imply chronic occlusion Poststenotic dilatation distal to severe stenoses Location CFA extends from inguinal ligament to bifurcation into superficial and profunda femoral arteries SFA courses through adductor (Hunter) canal in thigh SFA emerges at adductor hiatus in distal thigh Becomes popliteal artery at this level Very common location for occlusive disease Popliteal artery continues from adductor hiatus to terminate at origins of tibial vessels below knee Divided into above- and below-knee segments These divisions influence interventions Noninvasive Arterial Examination Duplex ultrasound Characterizes lesion morphology, severity, and extent Findings in 51-75% stenosis Prestenotic segment: Normal Intrastenotic segment: Peak systolic velocity (PSV) elevated > 2× normal; ± monophasic waveforms Poststenotic segment: Partial turbulence Findings in 76-99% stenosis Prestenotic segment: Increased pulsatility Intrastenotic segment: Increased PSV > 4× normal; monophasic waveforms Poststenotic segment: Marked turbulence; damped waveforms with high-grade obstruction Visible lumen narrowing on color Doppler Ankle-brachial index (ABI): Ratio of arterial pressures at ankle & brachial levels; screening accuracy increases when obtained both at rest and during exercise Normal: ≥ 1.0 Borderline: 0.91-0.99 Mild disease: 0.81-0.90 Moderate disease: 0.51-0.80 Moderate to severe disease: 0.31-0.50 Severe disease: ≤ 0.30 Calcified/noncompressible arteries: > 1.4 Segmental limb pressures: Blood pressure (BP) cuffs placed on leg at 4 levels; arterial pressures obtained Allows for approximate localization of disease BP drop ≥ 20 mm Hg, dampened waveform indicates flow-limiting lesion between cuffs Pulse volume recording (PVR): Combines segmental limb pressures with air plethysmography Multiple pneumatic cuffs placed along lower extremity; inflated with standardized volume of air Measure changes in limb volume at various levels and reflect regional changes in blood flow CT Findings CTA Accurately depicts stenoses, occlusions, and collateral vasculature in format similar to angiography Also depicts adjacent nonvascular anatomy Requires multidetector scanner, high contrast dose, rapid bolus injection, & sophisticated postprocessing Contrast-related renal dysfunction/allergy possible Heavily calcified plaque may limit rendered images Include source images for accurate interpretation MR Findings MRA Time-of-flight technique is inaccurate Due to flow-related artifacts Gadolinium-enhanced MRA is more accurate Similar findings to those of angiography or CTA but may inaccurately overestimate severity of stenoses Angiographic Findings DSA is gold standard for vessel characterization 1240

Diagnostic Imaging Cardiovascular Accurately demonstrates arterial anatomy, stenoses, occlusions, and collateral arterial pathways Invasive procedure but provides imaging guidance for percutaneous endovascular therapies Potential for hematoma, vessel injury, pseudoaneurysm, contrast allergy, renal failure Imaging Recommendations Best imaging tool MRA and CTA are both excellent imaging modalities Used to anatomically delineate/confirm disease suspected from noninvasive arterial examination DSA may sometimes be used for confirmatory imaging Particularly if endovascular therapy is planned Protocol advice If history and physical examination suggests arterial disease, obtain noninvasive arterial examination If study shows evidence of occlusive disease Use CTA or MRA to confirm level of disease May also use DSA with concurrent intervention If clinically uncertain extent of disease or equivocal noninvasive arterial examination Obtain CTA, MRA, or DSA DIFFERENTIAL DIAGNOSIS Atherosclerosis Occlusive disease Irregular, eccentric narrowing Extensive collateralization Aneurysmal disease Popliteal artery aneurysm Spontaneously thromboses rather than ruptures Distal embolization may also occur Embolic Disease Abrupt occlusion with meniscus configuration Typically occurs at bifurcations Frequently multifocal occlusions Lack of collateral vessels P.16:34

Requires search for embolic source: Proximal aneurysm, cardiac vegetations, or atrial thrombus Traumatic Occlusion Common cause of occlusion in young patients Extremity fracture or dislocation; penetrating injury Popliteal artery susceptible to dislocation injury Vasculitis Uncommon in femoral and popliteal arteries Typically affects tibioperoneal and foot arteries e.g., Buerger disease, Raynaud phenomenon Cystic Adventitial Disease Focal cystic fluid accumulation in arterial adventitia Affects popliteal artery in 85% of cases Can affect external iliac artery and CFA Causes smoothly tapered “spiral” stenosis or occlusion Produces symptoms of intermittent claudication Popliteal Artery Entrapment Aberrant arterial relationship to gastrocnemius muscles Causes arterial compression, thickening, and fibrosis Can lead to aneurysm, thrombosis, or distal emboli PATHOLOGY General Features Etiology Peripheral artery disease (PAD) Occlusive disease due to atherosclerotic plaques

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Diagnostic Imaging Cardiovascular From smooth muscle proliferation, extracellular lipid/collagen deposition, and inflammation Intraluminal plaque causes stenosis or occlusion Risk factors for PAD Family history Diabetes Hypercholesterolemia Smoking Most common etiology in older patients Trauma, vasculitis, emboli, tumor encasement Younger patients: Vasculitis and trauma are more likely Older patients: Atherosclerosis is more likely Staging, Grading, & Classification TransAtlantic Inter-Society Consensus (TASC) II: Comprehensive PAD management document; classifies anatomic lesions, makes treatment recommendations TASC II classification of femoropopliteal lesions TASC A lesion (endovascular treatment) Single stenosis ≤ 10 cm or occlusion ≤ 5 cm long TASC B lesion (endovascular treatment) Multiple stenoses or occlusions, each ≤ 5 cm long Single stenosis or occlusion ≤ 15 cm long (not involving infrageniculate popliteal artery) Heavily calcified occlusions ≤ 5 cm long Single popliteal stenosis TASC C lesion (surgery preferred; low-risk patients) Multiple stenoses or occlusions totaling > 15 cm (± heavy calcification) Recurrent stenoses or occlusions requiring retreatment after 2 endovascular interventions TASC D lesion (surgical treatment) CTO of SFA > 20 cm, involving popliteal artery CTO of popliteal artery and proximal trifurcation CLINICAL ISSUES Presentation Most common signs/symptoms Intermittent claudication Exercise-related pain or muscle cramping, worsening with activity and subsiding after rest Graded by distance patient is able to walk Location of pain may indicate level of obstruction Femoropopliteal artery occlusive disease typically causes thigh &/or calf claudication Symptoms vary with extent of arterial collaterals Other signs/symptoms Acute limb ischemia: May signal embolic occlusion Demographics Age Atherosclerotic disease Increased incidence in older patients Gender M>>F Natural History & Prognosis Severe untreated stenoses may progress to occlusion More complex interventions/surgery are required for occlusion vs. stenosis Treatment Acute embolic or thrombotic occlusion Treatment based upon severity of ischemia Severely ischemic limb is surgical emergency Requires urgent surgical revascularization May consider thrombolysis and endovascular revascularization for well-perfused limb Chronic occlusive disease Endovascular revascularization with angioplasty/stent Originally was considered temporizing measure 1242

Diagnostic Imaging Cardiovascular Now often primary treatment of choice Can delay or avoid surgical bypass Surgical bypass Long-term durability; remains gold standard Reversed or in situ saphenous vein bypass DIAGNOSTIC CHECKLIST Consider Thrombosed popliteal artery aneurysm in patient with acute onset of leg pain and popliteal artery occlusion SELECTED REFERENCES 1. Napoli A et al: Peripheral arterial occlusive disease: diagnostic performance and effect on therapeutic management of 64-section CT angiography. Radiology. 261(3):976-86, 2011 2. Bueno A et al: Diagnostic accuracy of contrast-enhanced magnetic resonance angiography and duplex ultrasound in patients with peripheral vascular disease. Vasc Endovascular Surg. 44(7):576-85, 2010 3. Chan D et al: Imaging evaluation of lower extremity infrainguinal disease: role of the noninvasive vascular laboratory, computed tomography angiography, and magnetic resonance angiography. Tech Vasc Interv Radiol. 13(1):11-22, 2010 4. Lyden SP et al: TASC II and the endovascular management of infrainguinal disease. J Endovasc Ther. 16(2 Suppl 2):II5-18, 2009 P.16:35

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(Left) Components of a lower extremity noninvasive arterial examination include ankle-brachial indices (ABIs), segmental limb pressures, and pulse volume recording. In this patient with severe claudication, the ABIs are markedly decreased. The drop in segmental limb pressures between the high and low thighs is consistent with bilateral SFA disease. (Right) CTA at thigh level shows an occluded left SFA with popliteal artery reconstitution at the adductor hiatus. The right SFA is patent but diseased.

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(Left) Left leg DSA shows (A) patent common and profunda femoral arteries. The SFA is occluded at its origin with (B) reconstitution of the above-knee segment of the popliteal artery via profunda femoral artery collaterals . (Right) (C) A catheter was advanced from a right femoral approach over the aortic bifurcation, and the tip was placed in the left common femoral artery. (D) A guidewire and catheter combination was successfully advanced through the SFA occlusion into the popliteal artery .

(Left) Spot radiograph shows that (E) an angioplasty (PTA) balloon has been placed over the guidewire and inflated in the recanalized SFA. (F) This was followed by a self-expanding stent placement with additional angioplasty within the stents to increase the luminal diameter. (Right) DSA after PTA and stenting shows (G) patency of the SFA in the thigh (H) extending into the popliteal artery . Although this was a TASC D lesion, for which surgical bypass is recommended, endovascular treatment was effective.

Cystic Adventitial Disease > Table of Contents > Section 16 - Peripheral Vasculature > Lower Extremity Vasculature > Cystic Adventitial Disease Cystic Adventitial Disease T. Gregory Walker, MD, FSIR Rahul Sheth, MD Key Facts Terminology Rare vascular disorder characterized by focal cystic accumulation of mucinous fluid in arterial adventitia Affects arteries adjacent to large joints Clinically may present with sudden onset of intermittent claudication in young male patients Imaging 1244

Diagnostic Imaging Cardiovascular Ultrasound: Shows focal arterial stenosis with anechoic or hypoechoic intramural cysts MR: T2 hyperintense, T1 variably intense cysts compressing arterial lumen DSA: Smooth tapering of mid-popliteal artery Tapering may be eccentric or concentric; may show spiral or scimitar shape of stenosis CECT: Compressed or narrowed popliteal artery with adjacent low-attenuation, smoothly marginated perivascular mass(es) Pathology Unilocular or multilocular mucin-containing cysts within arterial adventitial layer causing luminal compression with intact endothelium Clinical Issues Severity of ischemic symptoms varies; mainly depends on condition of affected popliteal artery Unlike typical claudication, symptoms can intermittently resolve or may progress rapidly May cause functional obstruction during exercise Management varies depending on condition of artery Surgical cyst evacuation with preservation of native artery is preferred treatment Vascular bypass with vein graft may be required if native artery cannot be preserved Cyst aspiration alone usually results in recurrence

(Left) (A) Anteroposterior right popliteal artery DSA shows a smoothly marginated severe stenosis in the midpopliteal artery. (B) In the oblique projection, it is evident that there is a more extensive area of arterial abnormality . There is an undulating or spiral appearance to the stenosis suggesting multifocal areas of extrinsic compression. (Right) Color Doppler ultrasound of the popliteal fossa shows an anechoic mass compressing the adjacent popliteal artery . The popliteal vein is unremarkable.

(Left) Axial PD MR shows that the popliteal arterial lumen

is compressed by cysts

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within the arterial adventitia.

Diagnostic Imaging Cardiovascular The popliteal vein and adjacent lesser saphenous vein are seen posteriorly. (Right) Axial T2WI MR also demonstrates that the popliteal arterial lumen is compressed by adventitial cysts . The hyperintense appearance of the cysts on T2WI MR is typical of cystic adventitial disease, as is the arterial compression. Clinically, patients may present with unilateral intermittent claudication. P.16:37

TERMINOLOGY Definitions Rare vascular disorder characterized by focal cystic accumulation of mucinous fluid in arterial adventitia Affects arteries adjacent to large joints Clinically may present with sudden onset of intermittent claudication in young male patients IMAGING General Features Best diagnostic clue MR imaging T2 hyperintense, T1 variable intensity cysts compressing arterial lumen Digital subtraction angiography (DSA) Solitary, smooth tapering of mid popliteal artery Tapering may be eccentric or concentric Vascular tree usually otherwise normal Location Adventitia of arteries adjacent to joints Popliteal artery is most commonly affected (85%) External iliac/common femoral arteries are next most frequent sites of involvement May rarely involve brachial, radial, ulnar, and axillary arteries Rarely, cystic adventitial disease can affect veins External iliac, femoral, popliteal, great and short saphenous, and wrist veins have been reported Size Cysts may be multiloculated May extend over several centimeters Imaging Recommendations Best imaging tool Initial evaluation with ultrasound MR/MRA may better characterize ultrasound findings DSA may be useful for surgical planning, thrombolysis MR Findings T1WI Cysts have variable signal intensity on T1WI Intensity depends upon degree of mucin Arterial lumen compression best seen on axial images Gadolinium enhancement and fat-suppression sequences are useful T2WI Cysts are hyperintense MRA Smooth popliteal artery stenosis at or above knee joint Usually nonspecific; resembles extrinsic compression of various etiologies Ultrasonographic Findings Color Doppler Duplex ultrasound shows focal arterial stenosis with intramural cysts Increased peak systolic velocity at stenosis Cysts can contain low-level echogenic material Cysts show no internal Doppler flow Arterial noninvasive ultrasound Decreased ankle-brachial index due to stenosis Segmental pressure and pulse volume drop across affected popliteal artery Angiographic Findings DSA Smoothly tapered, curvilinear or spiral stenosis 1246

Diagnostic Imaging Cardiovascular Usually affects above-knee popliteal artery segment Eccentric stenoses are most common Will produce classic scimitar-shaped stenosis Hourglass appearance of stenosis if concentric cysts Occasionally has nonspecific complete occlusion Poststenotic dilatation is usually absent Poorly developed collateral vessels Remainder of vascular tree is usually normal CT Findings CECT Compressed or narrowed popliteal artery with adjacent low-attenuation, smoothly marginated perivascular mass(es) CTA Appearance of popliteal artery and characteristics of stenosis similar to angiographic findings DIFFERENTIAL DIAGNOSIS Popliteal Artery Aneurysm Partially thrombosed popliteal artery aneurysm with patent central luminal channel Surrounding laminar thrombus may mimic cystic adventitial disease on ultrasound and angiography MR should distinguish from cystic adventitial disease Signal characteristics of thrombus differ from cysts' Frequently thrombose or cause distal embolization Latter is atypical for cystic adventitial disease Popliteal Artery Entrapment Aberrant relationship of artery to gastrocnemius muscle with resultant arterial compression Eventually causes adventitial thickening and fibrosis May lead to aneurysm formation, stenosis, thrombosis, &/or distal embolization MR shows abnormal artery and aberrant relationship to gastrocnemius muscle Conventional angiography is sensitive for entrapment but lacks information regarding muscular abnormality Peripheral Artery Disease Clinical symptoms are typically somewhat different from those of cystic adventitial disease Chronic claudication, often bilateral Rest pain may be present with severe stenoses Caused by atherosclerosis Imaging findings dissimilar to cystic adventitial disease Multiple arterial levels or segments are involved Spiral or scimitar-shaped stenosis is atypical Well-developed collateral circulation usually present Popliteal Artery Embolus Filling defect(s) in popliteal artery seen on CTA or DSA Meniscus at margin of occlusion on angiogram Poorly formed collaterals Involvement of multiple arterial levels or segments Acuteness of symptom onset is clinically similar to cystic adventitial disease Popliteal Fossa Mass Involves popliteal fossa rather than vasculature P.16:38

Symptoms of arterial insufficiency if significant arterial compromise from encasement or compression by mass May have associated popliteal venous thrombosis Trauma May result in acute popliteal artery injury Popliteal artery is especially susceptible to injury from posterior knee dislocation May result in transection or occlusion PATHOLOGY General Features Etiology 4 theories for cystic adventitial disease etiology Embryologic origin 1247

Diagnostic Imaging Cardiovascular Mucin-producing mesenchymal cells arising from adjacent joints are incorporated into vessel wall during development Cysts arise from cells producing synovial or ganglion cysts in adjacent joint Cysts migrate/herniate into arterial adventitia Myxomatous degenerative condition associated with systemic disease Repetitive trauma Gross Pathologic & Surgical Features Unilocular or multilocular mucin-containing cysts within arterial adventitial layer causing luminal compression with intact endothelium Microscopic Features Cysts found in adventitia; also located in media Media shows decreased smooth muscle cells and prominent mucinous degeneration circumferentially Suggests medial degeneration precedes cyst formation CLINICAL ISSUES Presentation Most common signs/symptoms Intermittent claudication &/or lower limb pain Severity of ischemic symptoms varies; mainly depends on condition of affected popliteal artery Claudication may be acute in onset with intervals of exacerbation and remission but rarely rest pain Unlike typical claudication, symptoms can intermittently resolve or may progress rapidly May cause functional obstruction during exercise Recovery time from pain is prolonged compared with typical claudication As cyst enlarges, can lead to vascular compression with stenosis or occlusion Other signs/symptoms Decrease in or loss of pulses; rarely, a popliteal bruit Pain posterior to knee Palpable &/or pulsatile mass behind knee Limb swelling Deep vein thrombosis Demographics Age Young to middle-aged patients (3rd-5th decades) Gender M:F = 5:1 Epidemiology Rare, accounting for 0.1% of all vascular disease Almost always unilateral Can rarely involve both popliteal arteries Natural History & Prognosis Persistent claudication that rarely progresses to rest pain or limb-threatening ischemia Distal embolization is rare given intact arterial intima Occlusion without thrombosis may occur Treatment Management varies depending on condition of artery Surgical cyst evacuation with preservation of native artery is preferred treatment Cyst aspiration alone usually results in recurrence Vascular bypass with vein graft may be required if native artery cannot be preserved Angioplasty is not beneficial, because it will not affect cystic compression of artery If arterial thrombosis has occurred, thrombolytic therapy may be instituted prior to surgical correction DIAGNOSTIC CHECKLIST Consider Cystic adventitial disease in differential diagnosis of young male presenting with new onset of unilateral claudication and diminished distal pulses Image Interpretation Pearls Popliteal ultrasound showing narrowed popliteal artery with adjacent hypoechoic or anechoic mass should be supplemented with MR or contrast-enhanced CT Can exclude or confirm cystic adventitial disease SELECTED REFERENCES 1. Bucci F et al: Cystic adventitial disease of the popliteal artery. Vascular. 20(6):311-3, 2012 1248

Diagnostic Imaging Cardiovascular 2. Paravastu SC et al: A contemporary review of cystic adventitial disease. Vasc Endovascular Surg. 46(1):5-14, 2012 3. Sucandy I et al: Surgical management of cystic adventitial disease of the popliteal artery. Am Surg. 78(6):E333-4, 2012 4. Wick MC et al: Claudication due to cystic adventitial degeneration: a classical differential diagnosis of atherosclerotic peripheral artery disease. Circulation. 125(15):1926-7, 2012 5. Wiwanitkit V: Cystic adventitial disease and high spatial resolution magnetic resonance imaging. Ann Vasc Surg. 26(3):443, 2012 6. Baxter AR et al: Cystic adventitial disease of the popliteal artery: is there a consensus in management? Vascular. 19(3):163-6, 2011 7. Tsilimparis N et al: Cystic adventitial disease of the popliteal artery: An argument for the developmental theory. J Vasc Surg. 45(6):1249-1252, 2007 8. Buijsrogge MP et al: “Intermittent claudication intermittence” as a manifestation of adventitial cystic disease communicating with the knee joint. Ann Vasc Surg. 20(5):687-9, 2006 9. Fox CJ et al: Cystic adventitial disease of the popliteal artery. J Vasc Surg. 39(6):1351, 2004 10. Elias DA et al: Clinical evaluation and MR imaging features of popliteal artery entrapment and cystic adventitial disease. AJR Am J Roentgenol. 180(3):627-32, 2003 11. Inoue Y et al: A case of popliteal cystic degeneration with pathological considerations. Ann Vasc Surg. 6(6):525-9, 1992 P.16:39

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(Left) Anteroposterior DSA of both popliteal arteries in a 35-year-old man with unilateral right intermittent claudication shows a smooth eccentric stenosis of the right popliteal artery. The curvilinear scimitar shape of the stenosis is characteristic of cystic adventitial disease. (Right) Axial CECT of both knees shows a round, low-attenuation mass compressing the right popliteal artery with only a flattened slit-like lumen remaining. The left popliteal artery is normal and so are both popliteal veins .

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(Left) Axial T1WI MR shows a low-signal cyst markedly compressing the popliteal artery, which appears as a flow void . Cysts have variable signal intensity on T1WI as the signal characteristics are dependent upon the amount of mucin contained within the cysts. (Right) Axial T2WI MR shows characteristic high-signal intensity within the adventitial cyst that compresses the popliteal artery . The cysts that occur in this disease process may be multiloculated & can extend over several centimeters.

(Left) Management of cystic adventitial disease depends on the condition of the underlying artery. Although surgical cyst evacuation and preservation of the artery are preferred, vascular bypass may be required if the native artery cannot be preserved. Sagittal color Doppler US after cyst evacuation & bypass shows cyst reaccumulation compressing the bypass . (Right) The cyst was aspirated, and typical mucinous contents were removed. Unfortunately, cyst aspiration alone usually results in recurrence.

Persistent Sciatic Artery > Table of Contents > Section 16 - Peripheral Vasculature > Lower Extremity Vasculature > Persistent Sciatic Artery Persistent Sciatic Artery Sanjeeva P. Kalva, MBBS, MD, FSIR Key Facts Terminology Persistence of embryonic sciatic or axial limb artery as major arterial channel to lower leg Imaging Internal iliac artery continues as sciatic artery and then as popliteal artery Hypoplastic external iliac, common femoral, and superficial femoral arteries (SFA) 2 types based on degree of SFA hypoplasia 1250

Diagnostic Imaging Cardiovascular Aneurysms in 25%, typically under gluteus maximus due to compression of artery by greater trochanter Top Differential Diagnoses Neurogenic mass Soft tissue sarcoma Aneurysms of inferior gluteal artery Gluteal abscess Pathology Congenital Clinical Issues Incidence: 0.25 per 1,000 Bilateral in 12-50%; aneurysms in 25% Pain/pulsatile mass in buttock and thigh Acute ischemia of leg due to thromboembolism Chronic ischemic symptoms of leg due to repeated distal microemboli Ligation/resection of aneurysm with interposition graft or femoropopliteal bypass Endovascular stenting or coiling ± femoropopliteal bypass graft Diagnostic Checklist Demonstrate continuation of inferior gluteal artery into thigh & its communication with popliteal artery

(Left) Graphic shows an artistic description of a persistent sciatic artery . The superficial femoral artery is hypoplastic and ends in a fork-like configuration. (Right) AP and oblique CTA images show a complete form of a persistent sciatic artery. The left internal iliac artery continues as a persistent sciatic artery in the thigh and connects to the popliteal artery. The superficial femoral artery is incomplete and ends in a fork-like configuration. Note the aneurysm .

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Diagnostic Imaging Cardiovascular (Left) Oblique CTA shows an incomplete form of a persistent sciatic artery. The superficial femoral artery is dominant and continues as the popliteal artery. The internal iliac artery continues as the persistent sciatic artery , which is small and atretic but connects to the popliteal artery at the knee. (Right) AP angiography shows a large-caliber, nontapering right internal iliac artery that continues into the thigh as a persistent sciatic artery . Note hypoplastic right iliofemoral arteries. P.16:41

TERMINOLOGY Definitions Persistence of embryonic sciatic or axial limb artery as major arterial channel to lower leg IMAGING General Features Best diagnostic clue Internal iliac artery continues as sciatic artery and then as popliteal artery Hypoplastic external iliac, common femoral, and superficial femoral arteries (SFA) Location Courses through greater sciatic foramen below piriformis to enter thigh Lies within or adjacent to sheath of sciatic nerve Enters popliteal fossa to continue as popliteal artery Size Varies, 6-15 mm Morphology 2 types based on degree of SFA hypoplasia Complete form: SFA is grossly hypoplastic or absent; persistent sciatic artery is dominant supply to leg Incomplete form: SFA is dominant supply to leg, and persistent sciatic artery is small ± communication with popliteal artery Usually tortuous course Premature atherosclerosis with plaques, calcification Aneurysms form in 25%, typically under gluteus maximus due to compression of artery by greater trochanter when sitting CTA and MRA Typical course of artery Large internal iliac artery and small external iliac, common femoral, and superficial femoral arteries Distal SFA terminates in forked configuration Aneurysms at typical location; thrombus and Ca++ Angiography Findings similar to those of CTA and MRA Ultrasound Useful to detect flow in aneurysm and differentiate from other gluteal masses Imaging Recommendations Best imaging tool Angiography, CTA, MRA Protocol advice CTA/MRA: Delayed phase as slow flow is common Angiography: Catheter tip in common iliac artery DIFFERENTIAL DIAGNOSIS Neurogenic Mass Soft tissue mass hypointense on T1, hyperintense on T2, variable enhancement Soft Tissue Sarcoma Soft tissue mass with variable attenuation/intensity and enhancement Aneurysms of Inferior Gluteal Artery No continuation of artery into thigh Normal-sized external iliac and femoral arteries Gluteal Abscess Fluid collection, hyperintense on T2, rim enhancement PATHOLOGY General Features 1252

Diagnostic Imaging Cardiovascular Etiology Congenital Associated abnormalities Hemihypertrophy/hypoplasia of leg Arteriovenous malformation Multiple angiomas/neuromas Neurofibromatosis Embryology At 6 mm stage embryo, primitive sciatic artery (axial limb artery) arises from umbilical artery and supplies lower limb bud At 12 mm stage, external iliac and femoral arteries develop At 18 mm stage, femoral artery communicates with popliteal artery At 22 mm stage, continuity of sciatic artery is interrupted, and femoropopliteal system becomes main supply to lower extremity Segments of primitive sciatic artery persist as inferior gluteal artery, companion artery to sciatic nerve, popliteal artery, and distal peroneal artery Failure of development of femoral arterial system leads to persistence of sciatic artery CLINICAL ISSUES Presentation Most common signs/symptoms May be asymptomatic Pain/pulsatile mass in buttock and thigh Absent common femoral pulse but palpable popliteal pulse Acute ischemia of leg due to thromboembolism Chronic ischemic symptoms of leg due to repeated distal microemboli Demographics Average age at presentation: 60 years M:F = 1:1 Incidence: 0.25 per 1,000 Bilateral in 12-50%; aneurysms in 25% Treatment Ligation/resection of aneurysm with interposition graft or femoropopliteal bypass Endovascular stenting or coiling ± femoropopliteal bypass graft DIAGNOSTIC CHECKLIST Image Interpretation Pearls Demonstrate continuation of inferior gluteal artery into thigh and its communication with popliteal artery SELECTED REFERENCES 1. Shutze WP et al: Persistent sciatic artery: collective review and management. Ann Vasc Surg. 7(3):303-10, 1993

Arteriovenous Fistula > Table of Contents > Section 16 - Peripheral Vasculature > Lower Extremity Vasculature > Arteriovenous Fistula Arteriovenous Fistula T. Gregory Walker, MD, FSIR Roy Bryan, MD, MBA Key Facts Terminology Arteriovenous fistula (AVF): Abnormal direct communication between adjacent artery and vein Arteriovenous malformation (AVM): Congenital abnormal arteriovenous communication Typically has central vascular nidus Imaging Best diagnostic clue Simultaneous arterial and venous opacification on arterial-phase CECT or DSA Turbulent, high-flow arteriovenous shunting on Doppler US DSA is used to evaluate complex cases; multiple findings Direct arterial-to-venous communication Enlarged feeding arteries and draining veins Adjacent vessel recruitment in chronic/large AVFs Dilated venous circulation distal to fistula Pathology 1253

Diagnostic Imaging Cardiovascular Almost always acquired, post-traumatic abnormalities Gunshot wound in 50% of cases Can be iatrogenic e.g., percutaneous catheterization, postoperative Less commonly congenital Can arise as part of vascular malformation Diagnostic Checklist Transcatheter embolization is primary treatment modality for acquired AVF Perform embolization as selectively as possible to minimize nontarget embolization Multiple arteriovenous communications may be present in large chronic acquired AVF All points of communication must be closed to achieve complete treatment

(Left) Color Doppler US in a patient with a pulsatile left groin mass after an arteriogram shows (A) a vascularized mass with an internal color flow “yin-yang” pattern. A narrow neck connects the mass to the left common femoral artery . The appearance is consistent with a pseudoaneurysm. (B) The left common femoral vein has an arterialized waveform typical of an AVF. (Right) Axial CECT confirms the pseudoaneurysm and shows contrast opacification of the left common femoral vein in the arterial phase.

(Left) Axial CECT at a more cephalad level better shows simultaneous opacification of the left common femoral artery and vein in the arterial phase of the examination. This confirms an iatrogenic AVF in addition to the pseudoaneurysm. There is no opacification of the contralateral common femoral vein , as the right side is normal. (Right) CTA shows that the pseudoaneurysm arises near the femoral artery bifurcation . The left-sided venous structures are opacified, whereas those on the right are not. P.16:43

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TERMINOLOGY Definitions Arteriovenous fistula (AVF): Abnormal direct communication between adjacent artery and vein Usually acquired but sometimes may be congenital Arteriovenous malformation (AVM): Congenital abnormal arteriovenous (AV) communication Typically has central vascular nidus Enlarges through recruitment of additional feeding arteries and draining veins IMAGING General Features Best diagnostic clue Simultaneous arterial and venous opacification on arterial-phase CECT or DSA Turbulent, high-flow AV shunting on Doppler US Location Occurs mainly in peripheral vasculature when acquired; can affect any organ when congenital Most frequently seen in lower extremities Occurs where artery & vein are in close proximity Size Variable; depends on size/location of involved vessels Draining vein dilates in response to high-flow arterialization AVF can increase in size if left untreated Imaging Recommendations Best imaging tool Arterial-phase CECT or DSA DSA is mainly used during transcatheter treatment Protocol advice Arterial-phase CECT: Very useful in diagnosis MR post-contrast fat-saturated sequences: Important in distinguishing AVF from vascular neoplasm CT Findings NECT Possible foreign bodies; shrapnel from prior trauma CTA Simultaneous arterial and venous opacification Angiographic Findings DSA for complex cases evaluation; multiple findings Direct arterial to venous communication Early contrast filling of involved veins Enlarged feeding arteries and draining veins Recruitment of adjacent vessels in chronic/large AVFs Dilated venous circulation distal to fistula Venous aneurysm may be present Due to chronic arterialization of vein Pseudoaneurysm may be present Extravascular contrast collection with delayed clearing; occurs at site of AV communication MR Findings T1WI Large vessels have flow void May see soft tissue evidence of prior trauma Post-contrast enhancement may help distinguish AVF from vascular tumors MRA Similar findings to CECT and DSA Enlargement of involved vessels Rapid arterial-to-venous transit time Ultrasonographic Findings Color Doppler Can identify direct arterial-to-venous communication Arterialized flow pattern in draining vein Both low- and high-resistance flow in supplying artery 1255

Diagnostic Imaging Cardiovascular Turbulent, high-velocity flow at AV communication May show any pseudoaneurysm related to AVF Appears as anechoic mass with internal color flow Flow pattern described as “yin-yang” DIFFERENTIAL DIAGNOSIS Vascular Neoplasm Hemangioma: Benign vascular tumor Occurs in capillary stage of development Present in infancy; proliferates over time Usually involutes during adulthood Usually cutaneous or mucosal lesion Also found in brain, liver, spleen, pancreas, kidneys Normal-caliber feeding vessels Early filling of vascular spaces that persists through venous phase, without venous shunting MR features Low signal on T1; very bright signal on T2 Normal arteries and veins Other vascular neoplasms Adrenal carcinoma Angiomyolipoma Hepatocellular carcinoma Melanoma Neuroendocrine tumors Primary vascular neoplasm (e.g., angiosarcoma) Renal cell carcinoma Thyroid carcinoma Vascular metastases from primary neoplasms Vascular Malformations Arteriovenous malformation Usually no history of trauma ˜ 60% occur in lower extremities Often have slower flow than AVFs Incomplete flow void on T1WI Bright signal intensity on T2WI Large lesions visible on CT and MR May need DSA for clarification/endovascular therapy Venous malformation Congenital low-flow lesion Normal feeding arteries Localized dilated venous structures Slow flow, delayed opacification on CTA and DSA Soft, nonpulsatile, without bruit Large lesions can be painful if thrombosis occurs May cause disfigurement Sclerotherapy is often used for treatment Hemodialysis Arteriovenous Fistula Surgically created AV communication Classic Brescia-Cimino fistula involves surgical anastomosis of radial artery to cephalic vein Provides long-term vascular access for hemodialysis P.16:44

After surgical creation, AVF requires maturation prior to being used for hemodialysis Typical maturation time is 4 weeks Surgically created fistula has same imaging characteristics as acquired or post-traumatic AVF Rapid AV shunting via direct communication Dilated, arterialized draining vein PATHOLOGY General Features 1256

Diagnostic Imaging Cardiovascular Etiology Almost always acquired, post-traumatic abnormalities Gunshot wound in 50% of cases Can be iatrogenic e.g., percutaneous catheterization, postoperative Less commonly congenital Can arise as part of vascular malformation Genetics Association with Parkes Weber syndrome: Port-wine stain, vascular malformations with at least 1 AVF, and hypertrophy of involved limb Acquired AVFs occur more frequently in lower than upper extremities Lower extremities are more often involved in trauma Iatrogenic postcatheterization AVFs usually involve common femoral arteries Gross Pathologic & Surgical Features Direct communication between artery and vein No interposed nidus, unlike AVM Multiple AV communications may be present if chronic Dilated venous channels distal to fistula Microscopic Features No signs of abnormal cellular proliferation CLINICAL ISSUES Presentation Most common signs/symptoms Localized, pulsatile soft tissue mass; can be painful Audible bruit and palpable thrill Venous dilatation Lymphedema in chronic fistulas Branham sign: Onset of bradycardia after temporary digital compression of AVF Other signs/symptoms Marked increase in cardiac venous return May result in abnormally high cardiac output and rapid heart rate Termed “high-output cardiac failure” AVF may cause steal phenomenon: Impaired arterial circulation distal to fistulous communication Causes distal tissue ischemia Natural History & Prognosis Spontaneous resolution is rare except in very small AVF Fistulas of all sizes can gradually enlarge With enlargement, additional arteries and veins may be recruited into fistula Treatment Surgical Ligation of fistula and associated branches Transcatheter embolization/occlusion Must determine whether vessel(s) can be sacrificed Consider any alternative treatment methods Embolization should be as selective as possible Catheter should be positioned close to fistula Must appropriately size embolic agent to prevent passage through AVF into venous circulation Results in nontarget embolization Coils are most commonly used embolic agents Variety of newer embolic agents allow endovascular treatment even of very large AVFs e.g., Amplatzer plug occluders, covered stents Can treat some AVFs with arterial covered stent High success rate (80-100%) with embolization Low complication rate Greatest concerns: Nontarget embolization and large infarcts; small infarcts are typically asymptomatic Risk for nontarget embolization increases with larger fistulous communications DIAGNOSTIC CHECKLIST Consider Transcatheter embolization is primary treatment modality for acquired AVF 1257

Diagnostic Imaging Cardiovascular Perform embolization as selectively as possible to minimize nontarget embolization Multiple AV communications may be present in large chronic acquired AVFs All points of communication must be closed to achieve complete treatment Image Interpretation Pearls Venous aneurysms may occur with large/chronic AVFs Due to chronic arterialization of vein Pseudoaneurysm may be associated with AVF at point of communication and may require treatment SELECTED REFERENCES 1. Garg N et al: Contemporary management of giant renal and visceral arteriovenous fistulae. J Endovasc Ther. 18(6):811-8, 2011 2. Sexton JA et al: Endovascular approaches to arteriovenous fistula. Adv Surg. 45:83-100, 2011 3. González SB et al: Imaging arteriovenous fistulas. AJR Am J Roentgenol. 193(5):1425-33, 2009 4. Spirito R et al: Endovascular treatment of a post-traumatic tibial pseudoaneurysm and arteriovenous fistula: case report and review of the literature. J Vasc Surg. 45(5):1076-9, 2007 5. Ray CE Jr et al: Endovascular repair of a large post-traumatic calf pseudoaneurysm and arteriovenous fistula. Mil Med. 171(7):659-61, 2006 6. Durakoglugil ME et al: High output heart failure 8 months after an acquired arteriovenous fistula. Jpn Heart J. 44(5):805-9, 2003 7. Li JC et al: Diagnostic criteria for locating acquired arteriovenous fistulas with color Doppler sonography. J Clin Ultrasound. 30(6):336-42, 2002 8. Sigler L et al: Aortocava fistula: experience with five patients. Vasc Surg. 35(3):207-12, 2001 9. Chen L et al: Surgical treatment of post-traumatic pseudoaneurysms and arteriovenous fistulas. Chin J Traumatol. 3(3):163-165, 2000 10. Picus D et al: Iatrogenic femoral arteriovenous fistulae: evaluation by digital vascular imaging. AJR Am J Roentgenol. 142(3):567-70, 1984 P.16:45

Image Gallery

(Left) Axial CECT in a patient with persistent severe right buttock pain after a bone marrow biopsy shows (A) the right superior gluteal artery coursing through the greater sciatic notch. (B) There is an enhancing mass arising from the superior gluteal artery. The appearance is consistent with a pseudoaneurysm. (Right) DSA via the right common iliac artery confirms the pseudoaneurysm and shows simultaneous filling of the common iliac vein and inferior vena cava , consistent with an AVF.

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(Left) Oblique DSA shows a catheter in the right internal iliac artery , which gives origin to the superior gluteal artery , from which the pseudoaneurysm arises. Filling of the venous structures in the arterial phase of the DSA is diagnostic of an AV communication which, in this case, is an iatrogenic AVF. (Right) A coaxial microcatheter was placed via the selective catheter into the superior gluteal artery for coil embolization of the pseudoaneurysm and closure of the AVF.

(Left) Unsubtracted DSA image shows that the embolization coils have been densely packed into the superior gluteal artery to completely exclude arterial perfusion of the pseudoaneurysm and the point of arteriovenous communication. (Right) DSA after coil embolization of the superior gluteal artery shows that there is no longer any opacification of the pseudoaneurysm and no filling of the AFV. This confirms effective transcatheter treatment of the iatrogenic injury.

Deep Vein Thrombosis > Table of Contents > Section 16 - Peripheral Vasculature > Lower Extremity Vasculature > Deep Vein Thrombosis Deep Vein Thrombosis Sanjeeva P. Kalva, MBBS, MD, FSIR Key Facts Terminology Deep vein thrombosis (DVT): Condition in which blood solidifies, producing blood clot (thrombus) within deep venous system, typically in lower limbs Imaging Filling defect in deep veins or pulmonary arteries Noncompressible vein with intraluminal echoes on ultrasound examination 1259

Diagnostic Imaging Cardiovascular Duplex Doppler ultrasound: First-line imaging tool; 90-100% sensitivity and specificity for acute DVT CECT and CT/MR venography good noninvasive imaging tools Conventional venography has 11% false-negative rate Top Differential Diagnoses Interpretation errors Technical errors Cellulitis Superficial thrombophlebitis Clinical Issues Acute DVT: Swollen, tender lower limb (swelling extent depends on DVT site), increased temperature Post-thrombotic syndrome: Sequelae of DVT resulting from chronic venous obstruction &/or acquired incompetence of valves Pulmonary embolism (PE) Lower extremity DVT is more often associated with PE than upper extremity DVT Above-knee DVT and pelvic DVT are more often associated with PE than below-knee DVT Anticoagulation therapy for above-knee DVT and PE; treatment for calf vein DVT is controversial Inferior vena cava filter considered if anticoagulation cannot be given or failed Catheter-directed thrombolysis reduces prevalence and severity of post-thrombotic syndrome

(Left) Axial ultrasound of the right common femoral vein shows nearly echo-free lumen of the vein. Note mild enlargement of the vein compared to the artery. The vein remains noncompressible, suggesting that there is thrombus within the vein. (Right) Sagittal color Doppler ultrasound of the left popliteal vein shows absence of color flow within the vein. Spectral Doppler shows no signal from the vein. These features are consistent with occlusive DVT.

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Diagnostic Imaging Cardiovascular (Left) Axial CECT of the abdomen shows filling defect within the common iliac veins consistent with acute DVT. Note venous enlargement and perivenous haziness secondary to perivenous inflammatory edema. (Right) Coronal MRV of thighs in a patient with pulmonary embolism shows low signal intensity filling defect within the left femoral vein with associated rim-like enhancement of the vein. These features are consistent with acute DVT. P.16:47

TERMINOLOGY Abbreviations Deep vein thrombosis (DVT) Definitions Deep vein thrombosis: Condition in which blood solidifies, producing blood clot (thrombus) within deep venous system, typically in lower limbs Can also be seen in upper limbs (especially related to central venous catheters) Pulmonary embolism (PE): Obstruction of pulmonary artery or 1 of its branches by embolus, usually blood clot derived from leg vein thrombosis Venous thromboembolic disease (VTED): Combined deep vein thrombosis and pulmonary embolism IMAGING General Features Best diagnostic clue Filling defect in deep veins or pulmonary arteries CT, MR or contrast venogram, pulmonary CTA Noncompressible vein, with intraluminal echoes on ultrasound examination Location Iliac veins extend from inguinal ligament and join to form inferior vena cava (IVC) Common femoral vein extends proximally from junction of femoral vein and deep femoral vein to inguinal ligament Femoral vein courses through Hunter canal in thigh to junction with common femoral vein proximally Popliteal vein extends proximally from paired tibial veins to Hunter canal Calf veins: Paired anterior tibial, posterior tibial, and peroneal veins Ultrasonographic Findings Grayscale ultrasound Acute thrombosis (˜ 14 days) Low echogenicity or nearly anechoic thrombus Venous distension; thrombosed vein substantially larger than adjacent artery Loss of compressibility: Thrombus excluded if vein can be completely compressed Free-floating thrombus: Most recently formed clot may not adhere to vein wall Collaterals: Tortuous veins bypassing occlusion, usually smaller than normal veins Subacute thrombosis (˜ 2 weeks to 6 months) Thrombus becomes more echogenic, variable Decreased thrombus and vein size: Retraction and lysis may reduce vein size Adherence of thrombus: Free-floating thrombus becomes attached to vein wall Resumption of flow: Luminal flow may be restored through recanalization of thrombus, but vein may remain noncompressible Collateralization: Collateral venous channels continue to develop Chronic phase (≥ 6 months) Post-thrombotic scarring: Fibroblasts invade nonlysed thrombus; organizes as fibrous tissue Wall thickening: Scarred veins have thick walls with reduced luminal diameter Echogenic intraluminal material: Post-thrombotic fibrous scars appear as plaque-like areas along vein; may occasionally calcify Synechiae: Formed from nonlysed thrombus attached to 1 side of vein wall; gradually transformed into fibrous band Fibrous cord: In veins which fail to recanalize, vein may be reduced to echogenic cord; smaller than normal vein Valve abnormalities: Valve damage associated with venous thrombosis; valve cusp thickening and restricted motion lead to reflux and stasis Pulsed Doppler Spontaneous flow (any waveform present) Expected in medium to large veins, but often not spontaneous in smaller calf veins 1261

Diagnostic Imaging Cardiovascular Phasic flow (variation in flow velocity with respiration) When phasic pattern absent, flow described as continuous, indicating obstruction closer to heart Valsalva maneuver Causes blood flow cessation in large and medium size veins, documenting venous patency from point of examination to thorax Augmentation (increased flow velocity with distal compression) Absent response indicates obstruction further from heart and close to site of examination Color Doppler Color Doppler: Detects low echo or anechoic thrombus that may be missed on grayscale US Demonstration of recanalized lumen in thrombus, collateralization Demonstration of reflux in valvular incompetence Power Doppler Particularly useful in demonstration of slow flow through recanalized lumen and collaterals Angiographic Findings Contrast venography was once gold standard Now infrequently used for diagnosis of DVT Filling defect in deep veins Contrast outlines incompletely occlusive thrombus “Tram track” sign of flow around thrombus Venography used in combination with percutaneous intervention such as catheter-directed thrombolysis Used in extensive ilio-femoral venous thrombosis, phlegmasia cerulea dolens Lysis may reduce incidence of chronic venous insufficiency Imaging Recommendations Best imaging tool Duplex Doppler ultrasound: First-line imaging tool; 90-100% sensitivity and specificity for acute DVT CECT and CT/MR venography good noninvasive imaging tools Assessment of pelvic veins and IVC; exclusion of pelvic and abdominal causes of DVT Conventional venography has 11% false-negative rate Reserved for use as problem solving aid Used in combination with catheter-directed or mechanical thrombolysis P.16:48

DIFFERENTIAL DIAGNOSIS Interpretation Errors Baker cyst Artifactual “echo contrast” from slow flow Thickened valve mistaken for thrombus in chronic venous obstruction Failure to identify duplicated vein Technical Errors Inadequate compression Improper use of color flow imaging Poor venous distension Misidentification of deep vs. superficial veins Cellulitis May mimic DVT clinically; swollen, tender extremity Superficial Thrombophlebitis Also clinically similar to DVT PATHOLOGY General Features Etiology Acquired prothrombotic states associated with DVT Immobilization, stroke, recent surgery (especially orthopedic), paralysis, DVT history (risk factor: 2.5) Obesity (risk factor: 1.5), malignancy (risk factor: 2.5) Cigarette smoking, hypertension Oral contraceptives, hormone replacement therapy, pregnancy, secondary homocystinemia Antiphospholipid syndrome, CHF, myeloproliferative disorders, nephrotic syndrome Inflammatory bowel disease, sickle cell anemia, polycythemia, age > 40 (risk factor: 2.2) 1262

Diagnostic Imaging Cardiovascular Genetics Number of inherited prothrombotic disease states Antithrombin III deficiency Protein C and protein S deficiency Factor V Leiden, factor II G20210A Primary hyperhomocysteinemia Dysfibrinogenemias and hypofibrinolysis CLINICAL ISSUES Presentation Most common signs/symptoms Acute DVT: Swollen, tender lower limb (swelling extent depends on DVT site), increased temperature Post thrombotic syndrome: Sequelae of DVT resulting from chronic venous obstruction &/or acquired incompetence of valves Chronic leg swelling, ankle pigmentation, ulceration in lower calf and ankle (gaiter zone) Other signs/symptoms With associated pulmonary embolus: Shortness of breath, pleuritic chest pain, tachycardia, hypoxia, hypotension Demographics Age Exponential increase in VTED with age > 40 years; 25-30 years ˜ 30 cases per 100,000; 70-79 years ˜ 300500 cases per 100,000 Gender M=F Epidemiology VTED: 70-113 cases per 100,000 per year; DVT: 48 per 100,000; PE: 23 per 100,000 in clinical studies in Caucasians with no postmortem data Race/ethnicity: 2.5-4× lower risk of development of VTED amongst Hispanics and Asian-Pacific islanders compared with Caucasians and African Americans Seasonal variation: Occurs in winter > summer About 25-50% idiopathic Natural History & Prognosis Tibial/peroneal thrombi resolve spontaneously in 40%, stabilize in 40%, propagate proximally in 20% Likelihood for pulmonary embolism: Iliac veins (77%), femoropopliteal veins (35-67%), calf veins (0-46%) Post-thrombotic syndrome in 20% of DVT Death after treated VTED: 30 day incidence ˜ 6% after incident DVT; 30 day incidence ˜ 12% after PE; death associated with cancer, age and cardiovascular disease Treatment Anticoagulation therapy for above-knee DVT and PE; treatment for calf vein DVT controversial Heparin anticoagulation (unfractionated or low molecular weight) initial treatment for acute DVT Oral warfarin begun once therapeutic heparinization achieved; follow international normalized ratio (INR) Warfarin for DVT usually 3-6 months; generally longer for PE; maybe lifelong for recurrent DVT/PE or prothrombotic tendencies IVC filter considered for patients with high PE risk Unsuitable patients for anticoagulation Recent surgery, bleeding peptic ulcer, bleeding diatheses, vascular neoplasm Recurrent DVT/PE following adequate anticoagulation Catheter-directed thrombolysis reduces prevalence and severity of post thrombotic syndrome Considered in extensive ilio-femoral venous thrombosis and venous gangrene Use limited by contraindications Increased risk of major bleeding and stroke Management chronic venous obstruction Valve repair or transplantation, venous bypasses Perforator interruption, stripping of superficial venous system if deep venous system patent Endovascular stenting DIAGNOSTIC CHECKLIST Image Interpretation Pearls Thrombus excluded if vein completely compressible SELECTED REFERENCES

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Diagnostic Imaging Cardiovascular 1. Arnoldussen CW et al: An imaging approach to deep vein thrombosis and the lower extremity thrombosis classification. Phlebology. 27 Suppl 1:143-8, 2012 2. Comerota AJ: The current role of operative venous thrombectomy in deep vein thrombosis. Semin Vasc Surg. 25(1):2-12, 2012 3. Tenna AM et al: Diagnostic tests and strategies in venous thromboembolism. Phlebology. 27 Suppl 2:43-52, 2012 4. Zwiebel WJ et al: Introduction to Vascular Sonography. 5th ed. Philadelphia: Elsevier Saunders. 403-78, 2005 P.16:49

Image Gallery

(Left) Axial color Doppler ultrasound shows partial nonfilling of left common femoral vein consistent with partial thrombosis. Color Doppler is useful to detect partial thrombus, mural adherent thrombus, and recanalized thrombus. (Right) Axial CTV of left leg shows calcification and webs and calcification within the left femoral vein consistent with chronic DVT. Chronic DVT is often characterized by a small or normal-sized vein with wall thickening, webs, and calcifications.

(Left) AP venography of right femoral vein shows multiple filling defects within the femoral vein and deep femoral vein , consistent with DVT. (Right) AP venography of left femoral vein shows filling defects within the femoral vein consistent with DVT. Venous valves are shown . Venography, though highly sensitive, is rarely performed nowadays for diagnosis of DVT. It is part of a catheter-directed thrombolysis for treatment of DVT.

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(Left) Axial CECT of the abdomen shows a filling defect within the enlarged left gonadal vein. Normal, patent inferior vena cava is also noted. (Right) Axial CECT of the pelvis shows filling defect within the left internal iliac vein with associated rim enhancement of the venous wall, consistent with acute DVT. CTV of the pelvis and abdomen is useful to detect pelvic vein DVT that otherwise would be difficult to detect with ultrasound.

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Diagnostic Imaging Cardiovascular

Index A Abdominal aorta and visceral vasculature, 12:76, 12:77, 12:78, 12:79, 12:80, 12:81, 12:82, 12:83, 12:84, 12:85, 12:86, 12:87, 12:88, 12:89, 12:90, 12:91 aortic aneurysm, 12:76, 12:77, 12:78, 12:79, 12:80, 12:81 contained, aortic aneurysm with rupture vs., 12:83 lower extremity aneurysms associated with, 16:26 aortic aneurysm, with rupture, 12:82, 12:83, 12:84, 12:85 aortic graft complications, 12:86, 12:87 aortic occlusion, 12:88, 12:89, 12:90, 12:91 approach to, 12:2, 12:3 See also Aortic syndrome, acute, approach to. acquired pathology, 12:2 congenital pathology, 12:2 images, 12:3 Abdominal aorta and visceral vasculature, anatomy, 12:20, 12:21, 12:22, 12:23, 12:24, 12:25 abdominal aorta and branches, 12:22 abdominal aorta and visceral vasculature, 12:23, 12:25 gross anatomy, 12:20 abdominal aorta, 12:20 arcade arrangement of visceral vessels, 12:20, 12:21 parietal branches, 12:20 renal arteries, 12:20 variant anatomy of aortic branches, 12:21 venous drainage of abdominal viscera, 12:21 visceral branches, 12:20 superior and inferior mesenteric arteries, 12:24 Abdominal hemorrhage due to anticoagulation, spontaneous, abdominal aortic aneurysm with rupture vs., 12:83 Abdominal or left flank pain, nutcracker syndrome associated with, 13:35 Abdominal situs inversus, heterotaxia syndromes vs., 2:57 Abdominal situs solitus and levocardia, heterotaxia syndromes vs., 2:57 Absence of pulmonary artery, unilateral. See Pulmonary artery interruption, proximal. Allergic angiitis and granulomatosis, branch pulmonary artery stenosis vs., 11:27 Alveolar edema, pulmonary venous hypertension/pulmonary edema vs., 9:28

American trypanosomiasis. See Chagas disease. Amyloidosis, cardiac, 7:46, 7:47, 7:48, 7:49 associated abnormalities, 7:48 clinical issues, 7:48 differential diagnosis, 7:48 genetics, 7:48, 7:49 imaging, 7:3, 7:46, 7:47, 7:49 pathology, 7:48, 7:49 staging, grading, & classification, 7:48 Anastomotic pseudoaneurysm, iliac artery aneurysmal disease vs., 16:21, 16:22 Aneurysms. See also Pseudoaneurysm. abdominal aortic, 12:76, 12:77, 12:78, 12:79, 12:80, 12:81 contained, aortic aneurysm with rupture vs., 12:83 lower extremity aneurysms associated with, 16:26 with rupture, 12:82, 12:83, 12:84, 12:85 aortic. See Aortic aneurysm. carotid dissecting, extracranial carotid pseudoaneurysm vs., 14:25 true, extracranial carotid pseudoaneurysm vs., 14:25 congenital, Chagas disease vs., 7:57 coronary artery, 8:30, 8:31 coronary fistula vs., 8:131 differential diagnosis, 8:31 ductus aneurysm, chronic posttraumatic aortic pseudoaneurysm vs., 12:37 gluteal artery, inferior, persistent sciatic artery vs., 16:41 iliac artery aneurysmal disease, 16:20, 16:21, 16:22, 16:23 differential diagnosis, 16:21, 16:22 iliac artery occlusive disease vs., 16:17 left ventricular absent pericardium vs., 5:35 post infarction, 8:96, 8:97, 8:98, 8:99 lower extremity, 16:24, 16:25, 16:26, 16:27 popliteal artery acute lower extremity ischemia vs., 16:30 cystic adventitial disease vs., 16:37 lower extremity aneurysms associated with, 16:26 post-stent, in-stent restenosis vs., 8:115 pulmonary artery, 11:10, 11:11, 11:12, 11:13 differential diagnosis, 11:11 pulmonary artery pseudoaneurysm vs., 11:9 renal artery, renal arteriovenous fistula vs., 15:25

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septal, membranous, associated with ventricular septal defect, 6:37 P.ii

sinus of Valsalva bicuspid aortic valve associated with, 4:22 characteristics, 6:37 pseudocoarctation associated with, 12:66 thoracic aortic, 12:26, 12:27, 12:28, 12:29, 12:30, 12:31 thoracic aortic, mycotic, 12:32, 12:33, 12:34, 12:35 abdominal aortic aneurysm with rupture vs., 12:83 differential diagnosis, 12:33 true, post-infarction left ventricular pseudoaneurysm vs., 8:101 venous aneurysms, pathology-based imaging issues, 13:9 Angina, unstable, acute myocardial infarction vs., 8:68 Angioma. See Hemangioma. Annular mitral valve calcification. See Mitral valve annular calcification. Annuloplasty ring, valvular prosthesis vs., 4:60 Anomalous left circumflex coronary artery, 8:22, 8:23 Anomalous left coronary artery, benign, 8:18, 8:19, 8:20, 8:21 clinical issues, 8:19 coronary fistula vs., 8:131 differential diagnosis, 8:19 imaging, 8:18, 8:19, 8:20, 8:21 malignant anomalous left coronary artery vs., 8:17 pathology, 8:19 Anomalous left coronary artery, malignant, 8:16, 8:17 benign anomalous left coronary artery vs., 8:19 differential diagnosis, 8:17 Anomalous pulmonary venous return partial. See Pulmonary venous return, partial anomalous. total. See Pulmonary venous return, total anomalous. Anomalous right coronary artery, 8:24, 8:25 benign variant, anomalous left circumflex coronary artery vs., 8:23 differential diagnosis, 8:25 malignant anomalous left coronary artery vs., 8:17 Aorta and great vessels, thoracic. See Thoracic aorta and great vessels. Aorta and visceral vasculature, abdominal. See Abdominal aorta and visceral vasculature.

Diagnostic Imaging Cardiovascular Aorta, proximal descending, fusiform enlargement of (normal variant), traumatic aortic laceration vs., 12:70 Aortic aneurysm atherosclerotic, mycotic aneurysm vs., 12:33 bicuspid aortic valve associated with, 4:22 ductus diverticulum vs., 12:74 familial thoracic, Marfan syndrome vs., 12:61 inflammatory abdominal aortic aneurysm with rupture vs., 12:83 mycotic aneurysm vs., 12:33 nontraumatic, chronic post-traumatic aortic pseudoaneurysm vs., 12:37 pseudocoarctation vs., 12:66 thrombosed, aortic dissection vs., 12:50 Aortic aneurysm, abdominal, 12:76, 12:77, 12:78, 12:79, 12:80, 12:81 clinical issues, 12:78 contained, aortic aneurysm with rupture vs., 12:83 imaging, 12:76, 12:77, 12:78 lower extremity aneurysms associated with, 16:26 Aortic aneurysm, abdominal, with rupture, 12:82, 12:83, 12:84, 12:85 clinical issues, 12:84 differential diagnosis, 12:83 imaging, 12:82, 12:83, 12:85 pathology, 12:84 Aortic aneurysm, mycotic, 12:32, 12:33, 12:34, 12:35 abdominal aortic aneurysm with rupture vs., 12:83 associated abnormalities, 12:34 clinical issues, 12:34 differential diagnosis, 12:33 imaging, 12:32, 12:33, 12:35 pathology, 12:33, 12:34 staging, grading, & classification, 12:34 Aortic aneurysm, thoracic, 12:26, 12:27, 12:28, 12:29, 12:30, 12:31 clinical issues, 12:27 differential diagnosis, 12:27 imaging, 12:26, 12:27, 12:28, 12:29, 12:30, 12:31 pathology, 12:27 Aortic arch cervical, pseudocoarctation associated with, 12:66 double. See Double aortic arch. persistent 5th arch, 2:28, 2:29 redundant. See Pseudocoarctation. right. See Right aortic arch. Aortic arch, interrupted bicuspid aortic valve associated with, 4:22 coarctation of aorta vs., 2:11 D-transposition of great arteries associated with, 2:37 pulmonary sling associated with, 2:32

truncus arteriosus associated with, 2:46 with critical aortic stenosis, infantile coarctation, and interrupted aortic arch, hypoplastic left heart syndrome vs., 2:53 Aortic atherosclerotic ulcer, penetrating, 12:44, 12:45, 12:46, 12:47 aortic dissection vs., 12:50 approach to, 12:4 clinical issues, 12:45 differential diagnosis, 12:45 imaging, 12:44, 12:45, 12:47 pathology, 12:45 staging, grading, & classification, 12:45 Aortic atresia. See Hypoplastic left heart syndrome. P.iii

Aortic buckling or kinking. See Pseudocoarctation. Aortic calcification, valvular prosthesis vs., 4:60 Aortic coarctation. See Coarctation of aorta. Aortic conduit, apical. See Left ventricular apical aortic conduit. Aortic dilatation, bicuspid aortic valve associated with, 4:22 Aortic dissection, 12:48, 12:49, 12:50, 12:51, 12:52, 12:53 abdominal aortic occlusion vs., 12:89 acute approach to, 12:4 infarction, left anterior descending distribution vs., 8:76 nonatherosclerotic myocardial infarction vs., 8:87 approach to, 12:4 benign anomalous left coronary artery vs., 8:19 bicuspid aortic valve associated with, 4:22 clinical issues, 12:50 coronary artery stenosis vs., 8:50 coronary thrombosis vs., 8:43 differential diagnosis, 12:50 familial, bicuspid aortic valve associated with, 4:22 imaging, 12:48, 12:49, 12:50, 12:51, 12:52, 12:53 malignant anomalous left coronary artery vs., 8:17 pathology, 12:50 persistent 5th arch vs., 2:29 renal artery atherosclerosis vs., 15:13 suspected, suggested MDCT protocol for, 12:5 uremic pericarditis vs., 5:21 Aortic enteric fistula, abdominal aortic aneurysm with rupture vs., 12:83 Aortic graft complications, 12:86, 12:87 Aortic insufficiency. See Aortic valve regurgitation.

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Aortic intramural hematoma, 12:40, 12:41, 12:42, 12:43 aortic dissection vs., 12:50 approach to, 12:4 clinical issues, 12:41 differential diagnosis, 12:41 imaging, 12:40, 12:41, 12:42, 12:43 pathology, 12:41 staging, grading, & classification, 12:41 Aortic laceration, traumatic, 12:68, 12:69, 12:70, 12:71 clinical issues, 12:70 differential diagnosis, 12:70 imaging, 12:68, 12:69, 12:71 pathology, 12:70 Aortic occlusion, abdominal, 12:88, 12:89, 12:90, 12:91 clinical issues, 12:90 differential diagnosis, 12:89, 12:90 imaging, 12:88, 12:89, 12:91 pathology, 12:90 Aortic pseudoaneurysm, chronic posttraumatic, 12:36, 12:37, 12:38, 12:39 associated abnormalities, 12:37 clinical issues, 12:37 differential diagnosis, 12:37 ductus diverticulum vs., 12:73 imaging, 12:36, 12:37, 12:38, 12:39 pathology, 12:37 Aortic root disease aortic regurgitation vs., 4:17 bicuspid aortic valve associated with, 4:22 Aortic rupture, mycotic aneurysm vs., 12:33 Aortic syndrome, acute, approach to, 12:4, 12:5, 12:6, 12:7, 12:8, 12:9 aortic dissection, 12:4 classification, 12:5 complications, 12:5 diagnosis, 12:4 images, 12:6, 12:7, 12:8, 12:9 intramural hematoma, 12:4 introduction, 12:4 penetrating atherosclerotic aortic ulcer, 12:4 pitfalls in diagnosis, 12:5 prognosis, 12:5 reporting, 12:5 suggested MDCT protocol for suspected aortic dissection, 12:5 surveillance, 12:5 treatment, 12:5 Aortic tortuosity, thoracic aortic aneurysm vs., 12:27 Aortic transection. See Aortic laceration, traumatic. Aortic trauma, abdominal aortic occlusion vs., 12:89 Aortic valve rheumatoid nodules, papillary fibroelastoma vs., 6:45 trauma, aortic regurgitation vs., 4:17 unicuspid, bicuspid aortic valve vs., 4:21 Aortic valve, anatomy

Diagnostic Imaging Cardiovascular CT and MR of aortic valve, 1:54 echocardiography, aortic and mitral valves, 1:52 radiography of prosthetic aortic and mitral valves, 1:46 structure and function, 1:15 Aortic valve, bicuspid, 4:20, 4:21, 4:22, 4:23 aortic dissection vs., 12:50 aortic regurgitation vs., 4:17 aortic stenosis vs., 4:9 associated abnormalities, 4:21, 4:22 clinical issues, 4:22 coarctation of aorta associated with, 2:12 differential diagnosis, 4:21 genetics, 4:21 imaging, 4:20, 4:21, 4:23 Marfan syndrome vs., 12:61 pathology, 4:21, 4:22 pseudocoarctation associated with, 12:66 staging, grading, & classification, 4:22 Aortic valve regurgitation, 4:16, 4:17, 4:18, 4:19 clinical issues, 4:18 differential diagnosis, 4:17, 4:18 dilated nonischemic cardiomyopathy vs., 7:20 P.iv

imaging, 4:16, 4:17, 4:19 pathology, 4:18 staging, grading, & classification, 4:18 Aortic valve replacement, transcatheter, 4:12, 4:13, 4:14, 4:15 approach to, 4:3 clinical issues, 4:13 diagnostic checklist, 4:13 imaging, 4:12, 4:13, 4:14, 4:15 Aortic valve stenosis, 4:8, 4:9, 4:10, 4:11 bicuspid aortic valve vs., 4:21 chronic, rheumatic heart disease vs., 4:79 clinical issues, 4:10 coronary artery stenosis vs., 8:50 critical, with infantile coarctation and interrupted aortic arch, hypoplastic left heart syndrome vs., 2:53 degenerative calcified, 4:9 differential diagnosis, 4:9, 4:10 hypertrophic cardiomyopathy vs., 7:10 imaging, 4:8, 4:9, 4:11 pathology, 4:10 pseudocoarctation associated with, 12:66 pulmonary atresia associated with, 2:50 severe, dilated nonischemic cardiomyopathy vs., 7:20 staging, grading, & classification, 4:10 supravalvular aortic stenosis vs., 4:10

bicuspid aortic valve associated with, 4:22 Aortic wall calcification, coronary artery calcification vs., 8:33 Aortitis. See also Giant cell arteritis; Takayasu arteritis. abdominal aortic occlusion vs., 12:89, 12:90 periaortitis, aortic graft complications vs., 12:87 Aortocaval fistula, abdominal aortic aneurysm with rupture vs., 12:83 Aortoenteric fistula, mycotic aneurysm vs., 12:33 Aortoiliac occlusive disease. See Aortic occlusion, abdominal. Apical aortic conduit. See Left ventricular apical aortic conduit. Apical ballooning syndrome. See Takotsubo cardiomyopathy. Apical hypertrophic cardiomyopathy. See Cardiomyopathy, hypertrophic, apical. Apicoaortic bypass. See Left ventricular apical aortic conduit. Argentaffinoma syndrome. See Carcinoid syndrome. Arrhythmias severe, hypoplastic left heart syndrome vs., 2:53 tachycardia idiopathic right ventricular outflow tachycardia, arrhythmogenic right ventricular dysplasia/cardiomyopathy vs., 7:32 paroxysmal supraventricular, hypoplastic left heart syndrome vs., 2:53 ventricular and supraventricular, left ventricular noncompaction associated with, 7:51 Arrhythmogenic right ventricular dysplasia/cardiomyopathy, 7:30, 7:31, 7:32, 7:33 chronic myocardial infarction vs., 8:72 clinical issues, 7:32 differential diagnosis, 7:31, 7:32 genetics, 7:32 imaging, 7:3, 7:4, 7:30, 7:31, 7:33 ischemic cardiomyopathy vs., 7:16 lipomatous hypertrophy of interatrial septum vs., 6:51 pathology, 7:32 sarcoidosis vs., 7:43 Arteriovenous communications and venolymphatic malformations, pathology-based imaging issues, 13:9 Arteriovenous fistula coronary. See Coronary fistula. extracranial carotid pseudoaneurysm vs., 14:25 hemodialysis, lower extremity arteriovenous fistula vs., 16:43, 16:44 lower extremity, 16:42, 16:43, 16:44, 16:45 renal, 15:24, 15:25, 15:26, 15:27

3

differential diagnosis, 15:25, 15:26 nutcracker syndrome vs., 13:35 vertebral, subclavian steal syndrome vs., 14:33 Arteriovenous malformations cranial (vein of Galen) or hepatic, hypoplastic left heart syndrome vs., 2:53 lower extremity arteriovenous fistula vs., 16:43 pulmonary. See Pulmonary arteriovenous malformation. renal, renal arteriovenous fistula vs., 15:25 Arteritis giant cell. See Giant cell arteritis. polyarteritis nodosa, 15:20, 15:21, 15:22, 15:23 differential diagnosis, 15:21 renal artery atherosclerosis vs., 15:13 renal fibromuscular dysplasia vs., 14:17 Takayasu. See Takayasu arteritis. Artifacts laminar flow, acute pulmonary embolism vs., 11:16 technical, cardiac thrombus vs., 6:26 Atherosclerosis femoropopliteal artery occlusive disease vs., 16:33 iliac artery occlusive disease vs., 16:17 mitral valve annular calcification associated with, 4:37 mitral valve annular calcification vs., 4:37 Atherosclerosis, extracranial, 14:12, 14:13, 14:14, 14:15 clinical issues, 14:14 differential diagnosis, 14:13, 14:14 extracranial carotid stenosis, 14:16, 14:17, 14:18, 14:19 P.v

genetics, 14:14 imaging, 14:12, 14:13, 14:15 pathology, 14:14 renal fibromuscular dysplasia vs., 14:17 staging, grading, & classification, 14:14 Atherosclerosis, post-coronary artery bypass graft, 8:124, 8:125, 8:126, 8:127 differential diagnosis, 8:125 post-coronary artery bypass graft thrombosis vs., 8:121 Atherosclerosis, renal artery, 15:12, 15:13, 15:14, 15:15 differential diagnosis, 15:13, 15:14 imaging, 15:12, 15:13, 15:15 Atherosclerotic aortic ulcer, penetrating. See Aortic atherosclerotic ulcer, penetrating. Atherosclerotic disease extracranial carotid stenosis, 14:16, 14:17, 14:18, 14:19 giant cell arteritis vs., 12:57 occlusive, lower extremity aneurysms vs., 16:25

Diagnostic Imaging Cardiovascular vertebral artery dissection vs., 14:29 Atherosclerotic plaque, coronary, 8:36, 8:37, 8:38, 8:39, 8:40, 8:41 clinical issues, 8:38 differential diagnosis, 8:38 imaging, 1:3, 8:36, 8:37, 8:38, 8:39, 8:40, 8:41 intraplaque hemorrhage, coronary artery dissection vs., 8:63 pathology, 8:38 ulcerated, ductus diverticulum vs., 12:73, 12:74 Atherosclerotic stenosis or occlusion iliac artery aneurysmal disease vs., 16:21 renal artery, 15:12, 15:13, 15:14, 15:15 Atherosclerotic ulceration, traumatic aortic laceration vs., 12:70 Athlete's heart, hypertrophic cardiomyopathy vs., 7:9 Atria, tumor extension into, 6:12, 6:13, 6:14, 6:15 clinical issues, 6:14 differential diagnosis, 6:13, 6:14 imaging, 6:12, 6:13, 6:15 pathology, 6:14 staging, grading, & classification, 6:14 Atrial myxoma, 6:16, 6:17, 6:18, 6:19 cardiac lipoma vs., 6:21 clinical issues, 6:17 differential diagnosis, 6:17 genetics, 6:17 imaging, 6:16, 6:17, 6:19 left atrial thrombus vs., 10:19 metastatic disease vs., 6:10 papillary fibroelastoma vs., 6:45 pathology, 6:17 Atrial septal defects, 3:10, 3:11, 3:12, 3:13, 3:14, 3:15 associated abnormalities, 3:12 clinical issues, 3:12 differential diagnosis, 3:11 endocardial cushion defect vs., 3:23 genetics, 3:12 imaging, 3:10, 3:11, 3:13, 3:14, 3:15 large, Ebstein anomaly vs., 2:63 partial anomalous pulmonary venous return associated with, 3:35 patent ductus arteriosus vs., 3:5 pathology, 3:12 pseudocoarctation associated with, 12:66 pulmonary sling associated with, 2:32 pulmonary valve regurgitation vs., 4:45 pulmonary valve stenosis associated with, 4:42 right heart failure vs., 9:8 sinus venosus partial anomalous pulmonary venous return associated with, 3:35 Scimitar syndrome associated with, 3:27 truncus arteriosus associated with, 2:46 ventricular septal defects vs., 3:17

Atrial situs inversus, L-transposition of great arteries associated with, 2:42 Atrioventricular canal defect. See Endocardial cushion defect. Atrioventricular discordance, with ventriculoarterial concordance, Ltransposition of great arteries vs., 2:42 Atrioventricular septal defect. See Endocardial cushion defect. Atrioventricular valves anatomy, 1:47 overriding, D-transposition of great arteries associated with, 2:37 Axillary vein thrombosis, subclavian vein thrombosis associated with, 16:14 Azygos arch enlargement, azygos continuation of inferior vena cava vs., 13:27, 13:28 Azygos continuation of inferior vena cava, 13:26, 13:27, 13:28, 13:29 differential diagnosis, 13:27, 13:28 Scimitar syndrome associated with, 3:27 Azygos region lymph node enlargement, azygos continuation of inferior vena cava vs., 13:28

B Behçet disease branch pulmonary artery stenosis vs., 11:27 pulmonary artery aneurysm associated with, 11:12 ß-thalassemia, iron overload syndrome associated with, 7:60 Bicuspid aortic valve. See Aortic valve, bicuspid. Biliary atresia, pulmonary sling associated with, 2:32 Biventricular noncompaction, left ventricular noncompaction associated with, 7:51 Blalock-Taussig shunt. See Tetralogy of Fallot: BT shunt. Bland-White-Garland syndrome, 8:26, 8:27 coronary fistula vs., 8:131 differential diagnosis, 8:27 P.vi

hypoplastic left heart syndrome vs., 2:53 “Blue baby” operation. See Tetralogy of Fallot: BT shunt. Blunt aortic trauma. See Traumatic aortic laceration. BMPR2 gene mutations, pulmonary venoocclusive disease associated with, 11:35 Brachiocephalic vein occlusion or stenosis, superior vena cava syndrome vs., 13:11 Brain attack. See Ischemic stroke, acute.

4

Brain parenchymal hypodensity (nonvascular causes), acute ischemic stroke vs., 14:8 Branch pulmonary artery stenosis, 11:26, 11:27, 11:28, 11:29 clinical issues, 11:28 differential diagnosis, 11:27, 11:28 imaging, 11:26, 11:27, 11:29 pathology, 11:28 staging, grading, & classification, 11:28 Bronchial branching, bilateral leftsided, Scimitar syndrome associated with, 3:27 Bronchial-intercostal trunk infundibulum, traumatic aortic laceration vs., 12:70 Bronchoalveolar lavage, pulmonary venoocclusive disease associated with, 11:35 Bronchogenic carcinoma, pericardial cyst vs., 5:32 Bronchogenic cyst pericardial cyst vs., 5:31 pulmonary sequestration associated with, 11:24 Bypass graft. See Coronary artery bypass graft.

C C-reactive protein, acute ischemic stroke associated with, 14:8 Calcification aortic, valvular prosthesis vs., 4:60 aortic wall, coronary artery calcification vs., 8:33 coronary artery, 8:32, 8:33, 8:34, 8:35 degenerative aortic regurgitation vs., 4:17 multivalvular disease vs., 4:73 mitral valve. See Mitral valve annular calcification. myocardial, constrictive pericarditis vs., 5:28 pericardial, coronary artery calcification vs., 8:33 Carcinoid syndrome, 4:68, 4:69, 4:70, 4:71 clinical issues, 4:70 differential diagnosis, 4:70 genetics, 4:70 imaging, 4:68, 4:69, 4:71 multivalvular disease vs., 4:73 pathology, 4:70 pulmonary valve regurgitation vs., 4:45 rheumatic heart disease vs., 4:79 tricuspid valve regurgitation associated with, 4:52 tricuspid valve stenosis associated with, 4:49 tricuspid valve stenosis vs., 4:49 Carcinoid tumor malignant, mitral stenosis vs., 4:25 pulmonary artery pseudoaneurysm vs., 11:9

Diagnostic Imaging Cardiovascular Cardiac anatomy, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, 1:21, 1:22, 1:23, 1:24, 1:25, 1:26, 1:27, 1:28, 1:29, 1:30, 1:31, 1:32, 1:33, 1:34, 1:35, 1:36, 1:37, 1:38, 1:39, 1:40, 1:41, 1:42, 1:43, 1:44, 1:45, 1:46, 1:47, 1:48, 1:49, 1:50, 1:51, 1:52, 1:53, 1:54, 1:55, 1:56, 1:57 anterior heart surface and right atrium, 1:22 anterior view of heart, anterior chest wall removed, 1:17 borders (margins) anatomy and function, 1:14 CT, 1:21 graphic, 1:18, 1:19 cardiac skeleton and heart valves, 1:45 chambers anatomy and function, 1:14 CT, 2-chamber view, 1:38 CT, 4-chamber view, 1:36 CT of left heart chambers, 1:28, 1:29 CT of right heart chambers, 1:24, 1:25 echocardiography 2- and 3-chamber views, 1:39 4-chamber and arch views, 1:37 coronary CT of normal heart, 1:30, 1:31 CT 2-chamber view, 1:38 4-chamber view, 1:36 aortic valve, 1:54 atrioventricular valve, 1:47 borders (margins), 1:21 coronary CT of normal heart, 1:30, 1:31 heart surfaces, borders, and sulci, 1:21 left atrium, 1:35 left heart chambers, 1:28, 1:29 left heart valves, 1:53 mitral valve, 1:55 overview, 1:16 right atrium, 1:34 right heart chambers, 1:24, 1:25 right heart valves, 1:50 sagittal CT of normal heart, 1:32, 1:33 short-axis view, 1:40 sulci or grooves, 1:21 surfaces, 1:21 CT/MR, overview, 1:16 echocardiography 2- and 3-chamber views, 1:39 4-chamber and arch views, 1:37 aortic and mitral valves, 1:52 short-axis view, 1:41 general anatomy and function, 1:14 imaging clues identifying morphologic right and left atria, 1:16 identifying morphologic right and left ventricles, 1:16 imaging the heart, 1:16 P.vii

left atrium CT, 1:35 graphic, 1:26 structure and function, 1:15

left ventricle graphic, 1:27 structure and function, 1:15 MR aortic valve, 1:54 normal heart sagittal view, 1:43, 1:44 short-axis view, 1:42 overview, 1:16 semilunar valves, 1:48 valve function, 1:56, 1:57 posterior heart surface and left atrium, 1:26 radiography of heart graphic, 1:20 overview, 1:16 prosthetic aortic and mitral valves, 1:46 right atrium CT, 1:34 graphic, 1:22 structure and function, 1:15 right ventricle graphic, 1:23 structure and function, 1:15 sagittal CT of normal heart, 1:32, 1:33 shape and orientation, 1:14 sulci or grooves anatomy and function, 1:14 CT, 1:21 graphic, 1:18, 1:19 surfaces anatomy and function, 1:14 CT, 1:21 graphic, 1:18, 1:19 valves anatomy, 1:15 cardiac skeleton and heart valves, 1:45 CT atrioventricular valve, 1:47 CT and MR of aortic valve, 1:54 left heart valves, 1:53 mitral valve, 1:55 right heart valves, 1:50 echocardiography of aortic and mitral valves, 1:52 left heart valves, 1:51 MR CT and MR of aortic valve, 1:54 semilunar valves, 1:48 valve function, 1:56, 1:57 radiography of prosthetic aortic and mitral valves, 1:46 tricuspid and pulmonic valves, 1:49 Cardiac computed tomography (CT), 1:2, 1:3, 1:4, 1:5, 1:6, 1:7 See also Cardiac anatomy, CT. coronary CT angiography, 1:2, 1:3 images, 1:5, 1:6, 1:7 imaging of coronary atherosclerotic plaque, 1:3 imaging protocol, 1:2 contrast injection, 1:2 data acquisition, 1:2 patient preparation, 1:2 introduction, 1:2 noncoronary cardiac CT, 1:4

5

patients with bypass grafts and stents, 1:3 Cardiac conduction system, anatomy and function, 1:14 Cardiac magnetic resonance (MR), 1:8, 1:9, 1:10, 1:11, 1:12, 1:13 See also Cardiac anatomy, MR. cine imaging, 1:8 CMR techniques, 1:8, 1:9 diagnostic findings in specific cardiomyopathies, 1:10 flow-sensitive imaging using velocityencoded sequences (phase-contrast imaging), 1:9 images, 1:11, 1:12, 1:13 introduction, 1:8 morphologic images bright blood imaging, 1:8 dark blood imaging, 1:8 perfusion imaging, 1:8, 1:9 standard CMR examination, 1:9 suggested protocols by indication, 1:10 viability imaging, 1:9 Cardiac tamponade. See Pericardial tamponade. Cardiac tumor, primary malignant, atrial myxoma vs., 6:17 Cardiac vein mapping, 10:16, 10:17 Cardiogenic shock, papillary muscle rupture vs., 8:79 Cardiomyopathy, 7:2, 7:3, 7:4, 7:5, 7:6, 7:7, 7:8, 7:9, 7:10, 7:11, 7:12, 7:13, 7:14, 7:15, 7:16, 7:17, 7:18, 7:19, 7:20, 7:21, 7:22, 7:23, 7:24, 7:25, 7:26, 7:27, 7:28, 7:29, 7:30, 7:31, 7:32, 7:33, 7:34, 7:35, 7:36, 7:37, 7:38, 7:39, 7:40, 7:41, 7:42, 7:43, 7:44, 7:45, 7:46, 7:47, 7:48, 7:49, 7:50, 7:51, 7:52, 7:53, 7:54, 7:55, 7:56, 7:57, 7:58, 7:59, 7:60, 7:61, 7:62, 7:63, 7:64, 7:65 apical hypertrophic. See Cardiomyopathy, hypertrophic, apical. arrhythmogenic. See Arrhythmogenic right ventricular dysplasia/cardiomyopathy. cardiac amyloidosis, 7:3, 7:46, 7:47, 7:48, 7:49 cardiac sarcoidosis. See Sarcoidosis, cardiac. Chagas disease, 7:54, 7:55, 7:56, 7:57 differential diagnosis, 7:55, 7:56 post-infarction left ventricular aneurysm vs., 8:98 diagnostic findings in specific cardiomyopathies, 1:10 dilated. See Cardiomyopathy, nonischemic dilated. endomyocardial fibrosis. See Endomyocardial fibrosis. hypereosinophilic syndrome, 7:38, 7:39, 7:40, 7:41 hypertrophic. See Cardiomyopathy, hypertrophic. P.viii

Diagnostic Imaging Cardiovascular imaging. See Cardiomyopathy, imaging. infiltrative. See Cardiomyopathy, infiltrative. iron overload syndrome. See Iron overload syndrome. ischemic. See Cardiomyopathy, ischemic. left ventricular noncompaction. See Left ventricular noncompaction. myocarditis. See Myocarditis. nonischemic dilated. See Cardiomyopathy, nonischemic dilated. restrictive. See Cardiomyopathy, restrictive. suggested protocols by indication, 1:10 Takotsubo cardiomyopathy. See Takotsubo cardiomyopathy. Cardiomyopathy, hypertrophic, 7:8, 7:9, 7:10, 7:11, 7:12, 7:13 atrial, cardiac thrombus vs., 6:26 cardiac amyloidosis vs., 7:47 clinical issues, 7:10 coronary artery stenosis vs., 8:50 differential diagnosis, 7:9, 7:10 fibroma vs., 6:47 genetics, 7:10 imaging, 7:3, 7:8, 7:9, 7:11, 7:12, 7:13 multivalvular disease vs., 4:73 myocardial bridge vs., 8:129 nonischemic dilated cardiomyopathy vs., 7:20 pathology, 7:10 right ventricular infarction vs., 8:84 staging, grading, & classification, 7:10 Cardiomyopathy, hypertrophic, apical Chagas disease vs., 7:55 endomyocardial fibrosis vs., 7:36 hypereosinophilic syndrome vs., 7:38 left ventricular noncompaction vs., 7:51 Cardiomyopathy, idiopathic dilated. See Cardiomyopathy, nonischemic dilated. Cardiomyopathy, imaging, 7:2, 7:3, 7:4, 7:5, 7:6, 7:7 amyloidosis, 7:3 arrhythomgenic right ventricular cardiomyopathy, 7:3, 7:4 cardiac sarcoidosis, 7:3 cost effectiveness, 7:4 hypertrophic cardiomyopathy, 7:3 images, 7:5, 7:6, 7:7 introduction, 7:2 iron overload syndromes, 7:4 ischemic cardiomyopathy, 7:2 left ventricular noncompaction, 7:3 myocarditis, 7:3 nonischemic dilated cardiomyopathy, 7:2 Cardiomyopathy, infiltrative hypertrophic cardiomyopathy vs., 7:9, 7:10 ischemic cardiomyopathy vs., 7:16 left ventricular hypertrophy vs., 9:23 myocarditis vs., 7:28 right ventricular hypertrophy vs., 9:25

Cardiomyopathy, ischemic, 7:14, 7:15, 7:16, 7:17 Chagas disease vs., 7:55 clinical issues, 7:16 differential diagnosis, 7:16 imaging, 7:2, 7:14, 7:15, 7:16, 7:17 myocarditis vs., 7:27 pathology, 7:16 staging, grading, & classification, 7:16 Cardiomyopathy, nonischemic dilated, 7:18, 7:19, 7:20, 7:21 chronic myocardial infarction vs., 8:72 clinical issues, 7:20 differential diagnosis, 7:19, 7:20 genetics, 7:20 imaging, 7:2, 7:18, 7:19, 7:21 ischemic cardiomyopathy vs., 7:16 left heart failure vs., 9:11 left ventricular noncompaction vs., 7:51 myocarditis vs., 7:27 pathology, 7:20 pericardial effusion vs., 5:38 rheumatic heart disease vs., 4:79 staging, grading, & classification, 7:20 Cardiomyopathy, restrictive, 7:22, 7:23, 7:24, 7:25 clinical issues, 7:24 constrictive pericarditis vs., 5:28 differential diagnosis, 7:23 dilated nonischemic cardiomyopathy vs., 7:19 imaging, 7:22, 7:23, 7:25 other causes, hypereosinophilic syndrome vs., 7:38 pathology, 7:23, 7:24 rheumatic heart disease vs., 4:79 staging, grading, & classification, 7:24 Cardiomyopathy, restrictive obliterative. See Endomyocardial fibrosis. Cardiosplenic syndromes. See Heterotaxia syndromes. Cardioverter-defibrillators, implantable. See Pacemakers/implantable cardioverterdefibrillators. Carotid aneurysm dissecting, extracranial carotid pseudoaneurysm vs., 14:25 true, extracranial carotid pseudoaneurysm vs., 14:25 Carotid artery atheromatous plaque, carotid dissection vs., 14:21 fenestration, carotid dissection vs., 14:21 internal, traumatic pseudoaneurysm, carotid dissection vs., 14:21 Carotid artery steal, right common, subclavian steal syndrome vs., 14:33 Carotid compressive lesion, extrinsic, extracranial carotid stenosis vs., 14:18 Carotid dissection, 14:20, 14:21, 14:22, 14:23 associated abnormalities, 14:22

6

clinical issues, 14:22 differential diagnosis, 14:21 extracranial atherosclerosis vs., 14:13 P.ix

extracranial carotid stenosis vs., 14:18 imaging, 14:20, 14:21, 14:23 pathology, 14:22 staging, grading, & classification, 14:22 Carotid fibromuscular dysplasia carotid dissection associated with, 14:22 carotid dissection vs., 14:21 extracranial atherosclerosis vs., 14:14 extracranial carotid pseudoaneurysm vs., 14:25 extracranial carotid stenosis vs., 14:18 vertebral artery dissection vs., 14:29 Carotid pseudoaneurysm, extracranial, 14:24, 14:25, 14:26, 14:27 associated abnormalities, 14:26 clinical issues, 14:26 differential diagnosis, 14:25, 14:26 imaging, 14:24, 14:25, 14:27 pathology, 14:26 Carotid pseudoaneurysm, traumatic, carotid dissection vs., 14:21 Carotid space schwannoma, carotid dissection vs., 14:21 Carotid stenosis, extracranial, 14:16, 14:17, 14:18, 14:19 clinical issues, 14:18 differential diagnosis, 14:18 imaging, 14:16, 14:17, 14:19 pathology, 14:18 Cassidy-Scholte syndrome. See Carcinoid syndrome. CATCH-22, truncus arteriosus associated with, 2:46 Catheterization, May-Thurner syndrome vs., 13:31 Catheters indwelling, chronic pulmonary embolism associated with, 11:20 left central venous malpositioning, persistent left superior vena cava vs., 13:23 Cavoatrial extension. See Atria, tumor extension into. Cellulitis, deep vein thrombosis of lower extremity vs., 16:48 Central venous catheter malpositioning, left, persistent left superior vena cava vs., 13:23 Cerebral aneurysms, coarctation of aorta associated with, 2:12 Cerebral arteries, extracranial. See Extracranial cerebral arteries. Cerebrovascular accident. See Ischemic stroke, acute. Chagas disease, 7:54, 7:55, 7:56, 7:57 clinical issues, 7:56 differential diagnosis, 7:55, 7:56 imaging, 7:54, 7:55, 7:57 pathology, 7:56

Diagnostic Imaging Cardiovascular post-infarction left ventricular aneurysm vs., 8:98 Chemotherapy, May-Thurner syndrome vs., 13:31 Cholecystitis coronary artery stenosis vs., 8:50 ischemia right coronary artery stenosis vs., 8:56 Chordae tendineae, tricuspid valve regurgitation associated with, 4:52 Chordal rupture, papillary muscle rupture vs., 8:79 Chromosome 22q11.2 (DiGeorge syndrome), truncus arteriosus associated with, 2:46 Churg-Strauss syndrome, polyarteritis nodosa vs., 15:21 Coarctation, atypical. See Pseudocoarctation. Coarctation of aorta, 2:10, 2:11, 2:12, 2:13, 2:14, 2:15 associated abnormalities, 2:12 bicuspid aortic valve associated with, 4:22 clinical issues, 2:12 D-transposition of great arteries associated with, 2:37 differential diagnosis, 2:11 imaging, 2:10, 2:11, 2:13, 2:14, 2:15 infantile, with critical aortic stenosis and interrupted aortic arch, hypoplastic left heart syndrome vs., 2:53 pathology, 2:12 pseudocoarctation vs., 12:65, 12:66 pulmonary sling associated with, 2:32 repair of, 2:4 with extraanatomic bypass, left ventricular apical aortic conduit vs., 4:83 staging, grading, & classification, 2:12 Takayasu arteritis vs., 12:55 ventricular septal defects associated with, 3:18 Cocaine abuse, coronary thrombosis vs., 8:43 Cockett syndrome. See May-Thurner syndrome. Common iliac artery occlusion or stenosis, abdominal aortic occlusion vs., 12:89 Computed tomography, cardiac. See Cardiac computed tomography (CT). Congenital heart disease, 2:2, 2:3, 2:4, 2:5, 2:6, 2:7, 2:8, 2:9, 2:10, 2:11, 2:12, 2:13, 2:14, 2:15, 2:16, 2:17, 2:18, 2:19, 2:20, 2:21, 2:22, 2:23, 2:24, 2:25, 2:26, 2:27, 2:28, 2:29, 2:30, 2:31, 2:32, 2:33, 2:34, 2:35, 2:36, 2:37, 2:38, 2:39, 2:40, 2:41, 2:42, 2:43, 2:44, 2:45, 2:46, 2:47, 2:48, 2:49, 2:50, 2:51, 2:52, 2:53, 2:54, 2:55, 2:56, 2:57, 2:58, 2:59, 2:60, 2:61, 2:62, 2:63, 2:64, 2:65, 2:66, 2:67, 2:68, 2:69, 2:70, 2:71, 2:72, 2:73, 2:74, 2:75, 2:76, 2:77, 2:78, 2:79, 2:80, 2:81, 2:82, 2:83, 2:84, 2:85, 2:86, 2:87

approach to. See Congenital heart disease, approach to. coarctation of aorta. See Coarctation of aorta. cor triatrium. See Cor triatrium. D-transposition of great arteries, 2:36, 2:37, 2:38, 2:39 differential diagnosis, 2:37, 2:38 truncus arteriosus vs., 2:45 double aortic arch. See Double aortic arch. Ebstein anomaly. See Ebstein anomaly. heterotaxia syndromes, 2:56, 2:57, 2:58, 2:59, 2:60, 2:61 differential diagnosis, 2:57 inferior vena cava anomalies associated with, 13:16 hypoplastic left heart syndrome. See Hypoplastic left heart syndrome. inferior vena cava anomalies associated with, 13:16 L-transposition of great arteries. See Transposition of great arteries. persistent 5th arch, 2:28, 2:29 proximal interruption of pulmonary artery, 2:84, 2:85, 2:86, 2:87 differential diagnosis, 2:85 P.x

pulmonary valve stenosis vs., 4:41 pulmonary atresia. See Pulmonary atresia. pulmonary sling, 2:30, 2:31, 2:32, 2:33, 2:34, 2:35 differential diagnosis, 2:31, 2:32 left, double aortic arch vs., 2:17 right aortic arch. See Right aortic arch. suggested protocols by indication, 1:10 tetralogy of Fallot. See Tetralogy of Fallot. tetralogy of Fallot: BT shunt, 2:76, 2:77 tetralogy of Fallot: definitive repair, 2:78, 2:79, 2:80, 2:81, 2:82, 2:83 truncus arteriosus. See Truncus arteriosus. Congenital heart disease, approach to, 2:2, 2:3, 2:4, 2:5, 2:6, 2:7, 2:8, 2:9 images, 2:5, 2:6, 2:7, 2:8, 2:9 introduction, 2:2 postoperative anatomy, 2:3, 2:4 aortic coarctation repair, 2:4 bidirectional Glenn shunt, 2:3 Fontan procedure, 2:3 Jatene arterial switch procedure, 2:4 Lecompte maneuver, 2:4 modified Blalock-Taussig shunt, 2:3 Norwood procedure, 2:4 palliative procedures, 2:3 pulmonary arterial banding, 2:3 Senning procedure, 2:4 septal defect repair, 2:4 tetralogy of Fallot repair, 2:4 transposition of great arteries repairs, 2:4

7

Van Praagh segmental approach, 2:2, 2:3 associated malformations, 2:3 atrioventricular connection, 2:3 position and origin of great vessels, 2:2, 2:3 ventricular loop orientation, 2:2 visceroatrial situs, 2:2 Congenital lobar emphysema (or hyperinflation), pulmonary sling vs., 2:31 Congestive heart failure. See Heart failure. Connective tissue disease branch pulmonary artery stenosis vs., 11:27 hereditary mitral valve prolapse vs., 4:30 mitral valve regurgitation associated with, 4:33 Constrictive pericarditis. See Pericarditis, constrictive. Cor pulmonale, 9:32, 9:33 Cor triatrium, 2:68, 2:69 differential diagnosis, 2:69 imaging, 2:68, 2:69 rheumatic heart disease vs., 4:79 staging, grading, & classification, 2:69 total anomalous pulmonary venous return vs., 3:31 Cor triatrium dexter, cor triatrium vs., 2:69 Coronary anatomy, 8:4, 8:5, 8:6, 8:7, 8:8, 8:9, 8:10, 8:11, 8:12, 8:13, 8:14, 8:15 18-segment coronary model, 8:15 aortic root and coronary arteries, 8:6 cardiac veins, 8:5 coronary artery origins, 8:7 and courses, 8:13 dominance, 8:5 imaging anatomy, 8:4 left anterior descending coronary artery, 8:4 left circumflex coronary artery, 8:4 left coronary arteries, 8:8, 8:10, 8:11 left main coronary artery, 8:4 left, right, and codominant systems, 8:12 normal variants and anomalies, 8:5 perfusion territories, 8:14 right coronary arteries, 8:9 right coronary artery, 8:4, 8:5 segmentation of coronary artery, 8:5 Coronary arteriovenous fistula. See Coronary fistula. Coronary artery aneurysm, 8:30, 8:31 coronary fistula vs., 8:131 differential diagnosis, 8:31 staging, grading, & classification, 8:31 Coronary artery anomalies bicuspid aortic valve associated with, 4:22 D-transposition of great arteries associated with, 2:37 left main coronary stenosis vs., 8:59

Diagnostic Imaging Cardiovascular myocardial bridge vs., 8:129 other anomalous right coronary artery vs., 8:25 Bland-White-Garland syndrome vs., 8:27 truncus arteriosus associated with, 2:46 Coronary artery bypass graft atherosclerosis. See Post-coronary artery bypass graft atherosclerosis. imaging, 1:3 thrombosis. See Post-coronary artery bypass graft thrombosis. Coronary artery calcification, 8:32, 8:33, 8:34, 8:35 clinical issues, 8:33, 8:34 differential diagnosis, 8:33 imaging, 1:3, 8:32, 8:33, 8:35 pathology, 8:33 Coronary artery disease, 8:2, 8:3, 8:4, 8:5, 8:6, 8:7, 8:8, 8:9, 8:10, 8:11, 8:12, 8:13, 8:14, 8:15, 8:16, 8:17, 8:18, 8:19, 8:20, 8:21, 8:22, 8:23, 8:24, 8:25, 8:26, 8:27, 8:28, 8:29, 8:30, 8:31, 8:32, 8:33, 8:34, 8:35, 8:36, 8:37, 8:38, 8:39, 8:40, 8:41, 8:42, 8:43, 8:44, 8:45, 8:46, 8:47, 8:48, 8:49, 8:50, 8:51, 8:52, 8:53, 8:54, 8:55, 8:56, 8:57, 8:58, 8:59, 8:60, 8:61, 8:62, 8:63, 8:64, 8:65, 8:66, 8:67, 8:68, 8:69, 8:70, 8:71, 8:72, 8:73, 8:74, 8:75, 8:76, 8:77, 8:78, 8:79, 8:80, 8:81, 8:82, 8:83, 8:84, 8:85, 8:86, 8:87, 8:88, 8:89, 8:90, 8:91, 8:92, 8:93, 8:94, 8:95, 8:96, 8:97, 8:98, 8:99, 8:100, 8:101, 8:102, 8:103, 8:104, 8:105, 8:106, 8:107, 8:108, 8:109, 8:110, 8:111, 8:112, 8:113, 8:114, 8:115, 8:116, 8:117, 8:118, 8:119, 8:120, 8:121, 8:122, 8:123, 8:124, 8:125, 8:126, 8:127, 8:128, 8:129, 8:130, 8:131, 8:132, 8:133 acute myocardial infarction. See Myocardial infarction, acute. anomalous left circumflex coronary artery, 8:22, 8:23 anomalous left coronary artery, benign. See Anomalous left coronary artery, benign. anomalous left coronary artery, malignant, 8:16, 8:17 benign anomalous left coronary artery vs., 8:19 differential diagnosis, 8:17 anomalous right coronary artery. See Anomalous right coronary artery. approach to, 8:2, 8:3 Bland-White-Garland syndrome, 8:26, 8:27 coronary fistula vs., 8:131 P.xi

differential diagnosis, 8:27 hypoplastic left heart syndrome vs., 2:53

chronic myocardial infarction, 8:70, 8:71, 8:72, 8:73 clinical manifestations, 8:2 acute coronary syndromes, 8:2 heart failure, 8:2 stable coronary artery disease, 8:2 sudden cardiac death, 8:2 coarctation of aorta associated with, 2:12 coronary artery aneurysm, 8:30, 8:31 coronary fistula vs., 8:131 differential diagnosis, 8:31 coronary artery dissection. See Coronary artery dissection. coronary artery stenosis. See Coronary artery stenosis. coronary atherosclerotic plaque. See Atherosclerotic plaque, coronary. coronary calcification, 8:32, 8:33, 8:34, 8:35 coronary embolism, 8:28, 8:29 coronary fistula. See Coronary fistula. coronary thrombosis, 8:42, 8:43, 8:44, 8:45, 8:46, 8:47 diagnostic strategies, 8:2, 8:3 acute coronary syndromes, 8:3 prevention, 8:3 stable coronary artery disease, 8:2, 8:3 in-stent restenosis, 8:114, 8:115, 8:116, 8:117, 8:118, 8:119 infarction, left anterior descending distribution, 8:74, 8:75, 8:76, 8:77 ischemia right coronary artery stenosis, 8:54, 8:55, 8:56, 8:57 left main coronary stenosis, 8:58, 8:59, 8:60, 8:61 left ventricular free wall rupture, 8:106, 8:107, 8:108, 8:109 myocardial bridge, 8:128, 8:129 coronary atherosclerotic plaque vs., 8:38 differential diagnosis, 8:129 nonatherosclerosis myocardial infarction, 8:86, 8:87, 8:88, 8:89 nontransmural myocardial infarction, 8:90, 8:91, 8:92, 8:93, 8:94, 8:95 papillary muscle rupture, 8:78, 8:79, 8:80, 8:81 post-angioplasty restenosis, 8:112, 8:113 post-coronary artery bypass graft atherosclerosis, 8:124, 8:125, 8:126, 8:127 differential diagnosis, 8:125 post-coronary artery bypass graft thrombosis vs., 8:121 post-coronary artery bypass graft thrombosis, 8:120, 8:121, 8:122, 8:123 differential diagnosis, 8:121 post-coronary artery bypass graft atherosclerosis vs., 8:125 post-infarction left ventricular aneurysm, 8:96, 8:97, 8:98, 8:99 post-infarction left ventricular pseudoaneurysm, 8:100, 8:101, 8:102, 8:103

8

post-infarction mitral regurgitation, 8:104, 8:105 right ventricular infarction, 8:82, 8:83, 8:84, 8:85 arrhythmogenic right ventricular dysplasia/cardiomyopathy vs., 7:31 differential diagnosis, 8:84 subclavian artery stenosis/occlusion associated with, 16:10 ventricular septal rupture, 8:110, 8:111 differential diagnosis, 8:111 papillary muscle rupture vs., 8:80 Coronary artery dissection, 8:62, 8:63, 8:64, 8:65 clinical issues, 8:63, 8:64 coronary thrombosis vs., 8:43 differential diagnosis, 8:63 genetics, 8:63 imaging, 8:62, 8:63, 8:65 left main coronary stenosis vs., 8:59 pathology, 8:63 post-angioplasty, post-angioplasty restenosis vs., 8:113 Coronary artery ectasia, other causes, coronary fistula vs., 8:132 Coronary artery fistula. See Coronary fistula. Coronary artery narrowing or occlusion. See Coronary artery stenosis. Coronary artery pseudoaneurysm, coronary artery aneurysm vs., 8:31 Coronary artery stenosis, 8:48, 8:49, 8:50, 8:51, 8:52, 8:53 clinical issues, 8:50 de novo, in-stent restenosis vs., 8:115 differential diagnosis, 8:50 following heart treatment, heart transplant vs., 9:16 imaging, 8:48, 8:49, 8:50, 8:51, 8:52, 8:53 malignant anomalous left coronary artery vs., 8:17 pathology, 8:50 post-angioplasty restenosis vs., 8:113 post-coronary artery bypass graft thrombosis vs., 8:121 Coronary artery stent coronary artery calcification vs., 8:33 imaging, 1:3 in-stent restenosis, 8:114, 8:115, 8:116, 8:117, 8:118, 8:119 Coronary atherosclerotic plaque. See Atherosclerotic plaque, coronary. Coronary cameral fistula. See Coronary fistula. Coronary CT angiography, 1:2, 1:3 Coronary CT, normal heart, 1:30, 1:31 Coronary embolism, 8:28, 8:29 Coronary fistula, 8:130, 8:131, 8:132, 8:133 anomalous left circumflex coronary artery vs., 8:23 anomalous right coronary artery vs., 8:25 Bland-White-Garland syndrome vs., 8:27

Diagnostic Imaging Cardiovascular clinical issues, 8:132 coronary artery aneurysm vs., 8:31 coronary artery to coronary vein, cardiac vein mapping vs., 10:17 differential diagnosis, 8:131, 8:132 imaging, 8:130, 8:131, 8:133 pathology, 8:132 P.xii

Coronary sinus, unroofed, cardiac vein mapping vs., 10:17 Coronary spasm acute myocardial infarction vs., 8:68 coronary artery stenosis vs., 8:50 ischemia right coronary artery stenosis vs., 8:56 left main coronary stenosis vs., 8:59 Takotsubo cardiomyopathy vs., 7:63 coronary syndromes, acute clinical manifestations, 8:2 diagnostic strategies, 8:3 Coronary thrombosis, 8:42, 8:43, 8:44, 8:45, 8:46, 8:47 clinical issues, 8:44 differential diagnosis, 8:43 imaging, 8:42, 8:43, 8:45, 8:46, 8:47 pathology, 8:43, 8:44 staging, grading, & classification, 8:45 Coronary vasculopathy, post heart transplant, coronary atherosclerotic plaque vs., 8:38 Cranial (vein of Galen) arteriovenous malformation, hypoplastic left heart syndrome vs., 2:53 Crista terminalis characteristics, 6:37 tumor mimics vs., 6:38 CT, cardiac. See Cardiac computed tomography (CT). CT cardiac venography. See Cardiac vein mapping. Cyanotic heart disease complex, left ventricular noncompaction associated with, 7:51 L-transposition of great arteries vs., 2:42 right-sided obstructive, with decreased pulmonary vascularity, Ebstein anomaly vs., 2:63 Cystic adventitial disease, 16:36, 16:37, 16:38, 16:39 clinical issues, 16:38 differential diagnosis, 16:37, 16:38 femoropopliteal artery occlusive disease vs., 16:34 imaging, 16:36, 16:37, 16:39 lower extremity aneurysms vs., 16:25 pathology, 16:38 Cystic medial necrosis, vertebral artery dissection associated with, 14:30

D D-transposition of great arteries. See Transposition of great arteries.

Davies disease. See Endomyocardial fibrosis. Deep brain stimulator, pacemakers/implantable cardioverterdefibrillators vs., 10:14 Deep venous thrombosis chronic, May-Thurner syndrome vs., 13:32 lower extremity, 16:46, 16:47, 16:48, 16:49 May-Thurner syndrome associated with, 13:32 Deep venous thrombosis, stenosis, or occlusion, upper extremity veins, superior vena cava syndrome vs., 13:12 Degenerative calcification aortic regurgitation vs., 4:17 multivalvular disease vs., 4:73 Dehydration and sepsis in children, renal vein thrombosis associated with, 15:30 Dextro transposition of great arteries. See Transposition of great arteries. Dextrocardia, true heterotaxia syndromes vs., 2:57 with abdominal situs solitus, Scimitar syndrome vs., 3:27 Diaphragm, accessory, Scimitar syndrome associated with, 3:27 Diaphragmatic eventration, Scimitar syndrome associated with, 3:27 Diaphragmatic hernia, congenital chronic post-traumatic aortic pseudoaneurysm associated with, 12:37 pulmonary sequestration associated with, 11:24 Dilated cardiomyopathy. See Cardiomyopathy, nonischemic dilated. Discordant transposition. See Transposition of great arteries. Diverticulum ductus diverticulum. See Ductus diverticulum. Kommerell diverticulum, ductus diverticulum vs., 12:74 Meckel diverticulum, pulmonary sling associated with, 2:32 post-infarction left ventricular pseudoaneurysm vs., 8:101 Double aortic arch, 2:16, 2:17, 2:18, 2:19, 2:20, 2:21 associated abnormalities, 2:17 azygos continuation of inferior vena cava vs., 13:28 clinical issues, 2:17 differential diagnosis, 2:17 imaging, 2:16, 2:17, 2:18, 2:19, 2:20, 2:21 ipsilateral. See Persistent 5th arch. pathology, 2:17 pulmonary sling associated with, 2:32 right aortic arch vs., 2:23 and right aortic arch with aortic diverticulum, pulmonary sling vs., 2:31

9

Double-lumen aortic arch. See Persistent 5th arch. Double-outlet right ventricle, ventricular septal defects associated with, 3:18 Drug abuse, polyarteritis nodosa vs., 15:21 Drug reaction, infectious pericarditis vs., 5:18 Drug therapy methysergide, rheumatic heart disease vs., 4:79 neoplastic pericarditis vs., 5:24 tricuspid valve stenosis vs., 4:49 Ductus aneurysm, chronic posttraumatic aortic pseudoaneurysm vs., 12:37 P.xiii

Ductus bulge or bump. See Ductus diverticulum. Ductus diverticulum, 12:72, 12:73, 12:74, 12:75 associated abnormalities, 12:74 clinical issues, 12:74 differential diagnosis, 12:73, 12:74 imaging, 12:72, 12:73, 12:75 pathology, 12:74 staging, grading, & classification, 12:74 traumatic aortic laceration vs., 12:70

E Ebstein anomaly, 2:62, 2:63, 2:64, 2:65, 2:66, 2:67 carcinoid syndrome vs., 4:70 clinical issues, 2:64 differential diagnosis, 2:63, 2:64 genetics, 2:64 imaging, 2:62, 2:63, 2:65, 2:66, 2:67 pathology, 2:64 pulmonary atresia associated with, 2:50 pulmonary atresia vs., 2:49 Edema alveolar, pulmonary venous hyertension/pulmonary edema vs., 9:28 hydrostatic pulmonary. See Pulmonary venous hypertension/pulmonary edema (cardiogenic). interstitial, pulmonary venous hypertension/pulmonary edema vs., 9:28 pulmonary noncardiogenic left heart failure vs., 9:12 right heart failure vs., 9:8 Ehlers-Danlos syndrome aortic dissection vs., 12:50 carotid dissection associated with, 14:22 lower extremity aneurysms vs., 16:25 Marfan syndrome vs., 12:61 mitral valve prolapse vs., 4:30 renal fibromuscular dysplasia vs., 15:18

Diagnostic Imaging Cardiovascular vertebral artery dissection associated with, 14:30 Electrophysiology, 10:2, 10:3, 10:4, 10:5, 10:6, 10:7, 10:8, 10:9, 10:10, 10:11, 10:12, 10:13, 10:14, 10:15, 10:16, 10:17, 10:18, 10:19, 10:20, 10:21 cardiac vein mapping, 10:16, 10:17 imaging before and after, 10:2, 10:3 atrial fibrillation/flutter ablation, 10:2 cardiac resynchronization therapy/implantable cardioverter defibrillator, 10:2 images, 10:3 ventricular arrhythmia ablation, 10:2 left atrial thrombus, 10:18, 10:19, 10:20, 10:21 pacemakers/ICDS, 10:12, 10:13, 10:14, 10:15 pulmonary vein mapping, 10:4, 10:5, 10:6, 10:7 pulmonary vein stenosis, 10:8, 10:9, 10:10, 10:11 Ellis van Crevald syndrome, atrial septal defects associated with, 3:12 Embolic disease femoropopliteal artery occlusive disease vs., 16:33, 16:34 iliac artery occlusive disease vs., 16:17 Embolism coronary, 8:28, 8:29 pulmonary. See Pulmonary embolism; Pulmonary embolism, acute; Pulmonary embolism, chronic. Embolization, acute lower extremity ischemia vs., 16:29 Embolization/iatrogenic, subclavian artery stenosis/occlusion vs., 16:10 Embolus coronary thrombosis vs., 8:43 lower extremity aneurysms vs., 16:25 popliteal artery, cystic adventitial disease vs., 16:37 septic, pulmonary arteriovenous malformations vs., 11:7 tumor thrombus/embolus acute pulmonary embolism vs., 11:16 subclavian vein thrombosis vs., 16:14 Endocardial cushion defect, 3:22, 3:23, 3:24, 3:25 associated abnormalities, 3:24 clinical issues, 3:24 differential diagnosis, 3:23 genetics, 3:24 imaging, 3:22, 3:23, 3:25 patent ductus arteriosus vs., 3:5 pathology, 3:24 staging, grading, & classification, 3:24 Endocarditis, infective, 4:54, 4:55, 4:56, 4:57 aortic regurgitation vs., 4:17 aortic stenosis vs., 4:10 carcinoid syndrome vs., 4:70 clinical issues, 4:56 differential diagnosis, 4:55 imaging, 4:54, 4:55, 4:57 mitral valve prolapse vs., 4:30

mitral valve regurgitation vs., 4:33 multivalvular disease vs., 4:73 mycotic aneurysm associated with, 12:34 papillary muscle rupture vs., 8:79, 8:80 pathology, 4:55, 4:56 pulmonary valve regurgitation vs., 4:45 staging, grading, & classification, 4:56 tricuspid valve regurgitation associated with, 4:52 valvular prosthesis complications vs., 4:66 Endocarditis parietalis fibroplastica. See Endomyocardial fibrosis. Endocarditis, prosthetic valve. See Valvular prosthesis complications. Endomyocardial fibroelastosis chronic myocardial infarction vs., 8:72 nontransmural myocardial infarction vs., 8:91, 8:92 tricuspid valve stenosis vs., 4:49 Endomyocardial fibrosis, 7:34, 7:35, 7:36, 7:37 clinical issues, 7:36 P.xiv

differential diagnosis, 7:35, 7:36 eosinophilic, tricuspid valve stenosis vs., 4:49 hypereosinophilic syndrome vs., 7:38 imaging, 7:34, 7:35, 7:37 pathology, 7:36 rheumatic heart disease vs., 4:79 Eosinophilic myocarditis. See Hypereosinophilic syndrome. Esophageal duplication cyst, pericardial cyst vs., 5:32 Esophageal lung, Scimitar syndrome associated with, 3:27 Eustachian valve characteristics, 6:37 tumor mimics vs., 6:38 Extracranial carotid stenosis. See Carotid stenosis, extracranial. Extracranial cerebral arteries, 14:2, 14:3, 14:4, 14:5, 14:6, 14:7, 14:8, 14:9, 14:10, 14:11, 14:12, 14:13, 14:14, 14:15, 14:16, 14:17, 14:18, 14:19, 14:20, 14:21, 14:22, 14:23, 14:24, 14:25, 14:26, 14:27, 14:28, 14:29, 14:30, 14:31, 14:32, 14:33, 14:34, 14:35 acute ischemic stroke, 14:6, 14:7, 14:8, 14:9, 14:10, 14:11 differential diagnosis, 14:8 subclavian artery stenosis/occlusion associated with, 16:10 approach to, 14:2, 14:3, 14:4, 14:5 diagnosis, 14:2 future imaging research, 14:3 images, 14:4, 14:5 imaging recommendations, 14:3 limitations and pitfalls, 14:3 North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria, 14:2

10

atherosclerosis, extracranial, 14:12, 14:13, 14:14, 14:15 differential diagnosis, 14:13, 14:14 renal fibromuscular dysplasia vs., 14:17 carotid dissection. See Carotid dissection. carotid pseudoaneurysm, extracranial, 14:24, 14:25, 14:26, 14:27 carotid stenosis, extracranial, 14:16, 14:17, 14:18, 14:19 subclavian steal syndrome, 14:32, 14:33, 14:34, 14:35 differential diagnosis, 14:33, 14:34 subclavian artery stenosis/occlusion associated with, 16:9 vertebral dissection, 14:28, 14:29, 14:30, 14:31 Extravascular collection, lower extremity aneurysms vs., 16:25 Extrinsic venous compression, subclavian vein thrombosis vs., 16:14

F “False” carotid aneurysm. See Carotid pseudoaneurysm, extracranial. FBN1 gene mutation, Marfan syndrome associated with, 12:61 Femoropopliteal artery occlusive disease, 16:32, 16:33, 16:34, 16:35 clinical issues, 16:34 differential diagnosis, 16:33, 16:34 imaging, 16:32, 16:33, 16:35 pathology, 16:34 staging, grading, & classification, 16:34 Fenfluramine usage, carcinoid syndrome vs., 4:70 Fibroelastic hamartoma. See Fibroma. Fibroelastoma, papillary, 6:44, 6:45 differential diagnosis, 6:45 imaging, 6:44, 6:45 mitral stenosis vs., 4:25 Fibroelastosis endomyocardial chronic myocardial infarction vs., 8:72 nontransmural myocardial infarction vs., 8:91, 8:92 tricuspid valve stenosis vs., 4:49 subendocardial, left ventricular noncompaction associated with, 7:52 Fibroma, 6:46, 6:47, 6:48, 6:49 associated abnormalities, 6:48 clinical issues, 6:48 differential diagnosis, 6:47, 6:48 genetics, 6:48 hemangioma vs., 6:41 imaging, 6:46, 6:47, 6:49 lipomatous hypertrophy of interatrial septum vs., 6:52 lymphoma vs., 6:58 pathology, 6:48 Fibromuscular dysplasia carotid. See Carotid aneurysm. vertebral artery dissection associated with, 14:30 vertebral artery dissection vs., 14:29

Diagnostic Imaging Cardiovascular Fibromuscular dysplasia, iliac artery iliac artery aneurysmal disease vs., 16:21, 16:22 iliac artery occlusive disease vs., 16:17 Fibromuscular dysplasia, renal, 15:16, 15:17, 15:18, 15:19 differential diagnosis, 15:17, 15:18 polyarteritis nodosa vs., 15:21 renal artery atherosclerosis vs., 15:14 Fibrosis, endomyocardial. See Endomyocardial fibrosis. Fibrous hamartoma. See Fibroma. 5th arch, persistent, 2:28, 2:29 Fistula aortic enteric, abdominal aortic aneurysm with rupture vs., 12:83 aortocaval, abdominal aortic aneurysm with rupture vs., 12:83 aortoenteric, mycotic aneurysm vs., 12:33 arteriovenous. See Arteriovenous fistula. coronary. See Coronary fistula. Fontan procedure, 2:3

G Gallbladder, absent, pulmonary sling associated with, 2:32 Gastric lung, Scimitar syndrome associated with, 3:27 P.xv

Gastrointestinal diseases coronary artery stenosis vs., 8:50 ischemia right coronary artery stenosis vs., 8:56 Gerbode defect, endocardial cushion defect vs., 3:23 Giant cell arteritis, 12:56, 12:57, 12:58, 12:59 aortic intramural hematoma vs., 12:41 clinical issues, 12:57 differential diagnosis, 12:57 imaging, 12:56, 12:57, 12:58, 12:59 pathology, 12:57 penetrating aortic atherosclerotic ulcer vs., 12:45 staging, grading, & classification, 12:57 Takayasu arteritis vs., 12:55 Glenn shunt, bidirectional, 2:3 Glomus vagale paraganglioma, carotid dissection vs., 14:21 Gluteal abscess, persistent sciatic artery vs., 16:41 Gluteal artery aneurysms, inferior, persistent sciatic artery vs., 16:41 Glycogen storage diseases, cardiac amyloidosis vs., 7:47 Gonadal vein inferior vena cava anomalies vs., 13:16 thrombosis, renal vein thrombosis vs., 15:30 Gorlin syndrome, fibroma associated with, 6:48

H Hamartoma, fibrous/fibroelastic. See Fibroma. Heart anatomy. See Cardiac anatomy. Heart disease, congenital. See Congenital heart disease. Heart failure, 9:2, 9:3, 9:4, 9:5, 9:6, 9:7, 9:8, 9:9, 9:10, 9:11, 9:12, 9:13, 9:14, 9:15, 9:16, 9:17, 9:18, 9:19, 9:20, 9:21, 9:22, 9:23, 9:24, 9:25, 9:26, 9:27, 9:28, 9:29, 9:30, 9:31, 9:32, 9:33 approach to. See Heart failure, approach to. cor pulmonale, 9:32, 9:33 heart transplant, 9:14, 9:15, 9:16, 9:17 left heart failure. See Left heart failure. left ventricular hypertrophy, 9:22, 9:23 PVH/pulmonary edema (cardiogenic), 9:26, 9:27, 9:28, 9:29, 9:30, 9:31 right heart failure, 9:6, 9:7, 9:8, 9:9 cor pulmonale vs., 9:33 differential diagnosis, 9:8 right ventricular hypertrophy, 9:24, 9:25 ventricular assist devices, 9:18, 9:19, 9:20, 9:21 left ventricular apical aortic conduit vs., 4:83 Heart failure, approach to, 9:2, 9:3, 9:4, 9:5 etiology, determination of, 9:3 images, 9:4, 9:5 imaging/assessment techniques, 9:2, 9:3 cardiac catheterization, 9:3 chest radiograph, 9:2 computed tomography, 9:2, 9:3 echocardiography, 9:2 electrocardiogram, 9:2 late gadolinium enhancement MR, 9:3 magnetic resonance imaging, 9:3 radionuclide ventriculography, 9:2 single-photon emission computed tomography, 9:2 introduction, 9:2 pathophysiology, 9:2 prevalence, 9:2 treatment, 9:2 Heart transplant, 9:14, 9:15, 9:16, 9:17 clinical issues, 9:16 differential diagnosis, 9:16 imaging, 9:14, 9:15, 9:16, 9:17 pathology, 9:16 Hemangioma, 6:40, 6:41, 6:42, 6:43 cardiac sarcoma vs., 6:31 clinical issues, 6:42 differential diagnosis, 6:41, 6:42 fibroma vs., 6:47 imaging, 6:40, 6:41, 6:43 lower extremity arteriovenous fistula vs., 16:43 lymphoma vs., 6:58 pathology, 6:42

11

Hemangiomatosis, pulmonary capillary, pulmonary venoocclusive disease vs., 11:35 Hematoma aortic intramural. See Aortic intramural hematoma. pericardial cyst vs., 5:31 pericardial, left ventricular free wall rupture vs., 8:107 Hematuria, nutcracker syndrome associated with, 13:35 Hemochromatosis gene mutation, iron overload syndrome associated with, 7:60 iron overload syndrome vs., 7:60 Hemodialysis arteriovenous fistula, lower extremity arteriovenous fistula vs., 16:43, 16:44 Hemopericardium due to other etiologies, neoplastic pericarditis vs., 5:24 left ventricular free wall rupture vs., 8:107 Hepatic arteriovenous malformation, hypoplastic left heart syndrome vs., 2:53 Hepatic congestion, tricuspid valve regurgitation associated with, 4:52 Heterotaxia syndromes, 2:56, 2:57, 2:58, 2:59, 2:60, 2:61 clinical issues, 2:58 differential diagnosis, 2:57 genetics, 2:57 imaging, 2:56, 2:57, 2:59, 2:60, 2:61 inferior vena cava anomalies associated with, 13:16 pathology, 2:57, 2:58 staging, grading, & classification, 2:57, 2:58 HFE gene mutation, iron overload syndrome associated with, 7:60 Hiatal hernia coronary artery stenosis vs., 8:50 P.xvi

ischemia right coronary artery stenosis vs., 8:56 Hilar lymphadenopathy, pulmonary arterial hypertension vs., 11:31, 11:32 Hirschsprung disease, pulmonary sling associated with, 2:32 Holt-Oram syndrome, atrial septal defects associated with, 3:12 Homocysteine, acute ischemic stroke associated with, 14:8 Hormonal therapy, May-Thurner syndrome vs., 13:31 Horseshoe kidney, inferior vena cava anomalies associated with, 13:16 Horseshoe lung partial anomalous pulmonary venous return associated with, 3:35 pulmonary sling associated with, 2:32 Scimitar syndrome associated with, 3:27

Diagnostic Imaging Cardiovascular Hughes-Stovin syndrome, pulmonary artery aneurysm associated with, 11:12 Hydatid cyst, pericardial cyst vs., 5:32 Hydrostatic pulmonary edema. See Pulmonary venous hypertension/pulmonary edema (cardiogenic). Hypercoagulable states, inherited, renal vein thrombosis associated with, 15:30 Hyperdense vessel mimics, acute ischemic stroke vs., 14:8 Hypereosinophilic syndrome, 7:38, 7:39, 7:40, 7:41 clinical issues, 7:40 differential diagnosis, 7:39 genetics, 7:40 imaging, 7:38, 7:39, 7:41 pathology, 7:39, 7:40 Hyperserotonemia. See Carcinoid syndrome. Hypertension cardiac amyloidosis vs., 7:47 coronary artery stenosis vs., 8:50 pulmonary. See Pulmonary arterial hypertension. systemic arterial, hypertrophic cardiomyopathy vs., 7:9 systemic venous, tricuspid valve regurgitation associated with, 4:52 Hypertensive heart disease, restrictive cardiomyopathy vs., 7:23 Hypertrophic cardiomyopathy. See Cardiomyopathy, hypertrophic. Hypervascular neoplasm, pulmonary artery pseudoaneurysm vs., 11:9 Hypogenetic lung/pulmonary venolobar syndrome. See Scimitar syndrome. Hypoplastic left heart syndrome, 2:52, 2:53, 2:54, 2:55 clinical issues, 2:54 D-transposition of great arteries vs., 2:38 differential diagnosis, 2:53 genetics, 2:54 imaging, 2:52, 2:53, 2:55 pathology, 2:54 total anomalous pulmonary venous return vs., 3:31 truncus arteriosus vs., 2:45

I Idiopathic hypertrophic subaortic stenosis. See Cardiomyopathy, hypertrophic. Iliac artery common, occlusion or stenosis, abdominal aortic occlusion vs., 12:89 endofibrosis, iliac artery occlusive disease vs., 16:17 Iliac artery aneurysmal disease, 16:20, 16:21, 16:22, 16:23 clinical issues, 16:22 differential diagnosis, 16:21, 16:22

iliac artery occlusive disease vs., 16:17 imaging, 16:20, 16:21, 16:23 pathology, 16:22 Iliac artery dissection iliac artery aneurysmal disease vs., 16:21 iliac artery occlusive disease vs., 16:17 Iliac artery fibromuscular dysplasia iliac artery aneurysmal disease vs., 16:21, 16:22 iliac artery occlusive disease vs., 16:17 Iliac artery occlusive disease, 16:16, 16:17, 16:18, 16:19 clinical issues, 16:18 differential diagnosis, 16:17, 16:18 imaging, 16:16, 16:17, 16:19 pathology, 16:18 staging, grading, & classification, 16:18 Iliac vein compression syndrome. See May-Thurner syndrome. Iliocaval vein syndrome. See MayThurner syndrome. Immobilization, May-Thurner syndrome vs., 13:31 Imperforate anus, pulmonary sling associated with, 2:32 Implantable cardioverter-defibrillators. See Pacemakers/implantable cardioverter-defibrillators. In-stent restenosis, 8:114, 8:115, 8:116, 8:117, 8:118, 8:119 Infarction left anterior descending distribution, 8:74, 8:75, 8:76, 8:77 myocardial. See Myocardial infarction. perioperative, post-coronary artery bypass graft thrombosis vs., 8:121 post-infarction left ventricular aneurysm, 8:96, 8:97, 8:98, 8:99 post-infarction left ventricular pseudoaneurysm, 8:100, 8:101, 8:102, 8:103 post-infarction left ventricular rupture. See Ventricular septal rupture. post-infarction mitral regurgitation, 8:104, 8:105 right ventricular, 8:82, 8:83, 8:84, 8:85 arrhythmogenic right ventricular dysplasia/cardiomyopathy vs., 7:31 P.xvii

differential diagnosis, 8:84 Infectious aneurysm. See Aortic aneurysm, mycotic. Infectious pericarditis, 5:16, 5:17, 5:18, 5:19 Infective endocarditis. See Endocarditis, infective. Inferior vena cava and tributaries, variant anatomy, 13:3, 13:7 Inferior vena cava anomalies, 13:14, 13:15, 13:16, 13:17 associated abnormalities, 13:16 clinical issues, 13:16 differential diagnosis, 13:15, 13:16

12

genetics, 13:16 imaging, 13:14, 13:15, 13:17 inferior vena cava occlusion associated with, 13:20 inferior vena cava occlusion vs., 13:20 pathology, 13:16 types of, 13:15 Inferior vena cava, azygos continuation of, 13:26, 13:27, 13:28, 13:29 associated abnormalities, 13:28 clinical issues, 13:28 differential diagnosis, 13:27, 13:28 genetics, 13:28 imaging, 13:26, 13:27, 13:29 pathology, 13:28 Scimitar syndrome associated with, 3:27 Inferior vena cava, interrupted. See Inferior vena cava, azygos continuation of. Inferior vena cava occlusion, 13:18, 13:19, 13:20, 13:21 associated abnormalities, 13:20 differential diagnosis, 13:19, 13:20 imaging, 13:18, 13:19, 13:21 intrahepatic, due to tumor or thrombosis, azygos continuation of inferior vena cava vs., 13:28 pathology, 13:20 Infiltrative cardiomyopathy. See Cardiomyopathy, infiltrative. Interatrial septum, lipomatous hypertrophy of. See Lipomatous hypertrophy, interatrial septum. Intercostal vein, left superior, partial anomalous pulmonary venous return vs., 3:35 Internal carotid artery pseudoaneurysm, traumatic, carotid dissection vs., 14:21 Interpretation errors, deep vein thrombosis of lower extremity vs., 16:48 Interstitial edema, pulmonary venous hypertension/pulmonary edema vs., 9:28 Intraabdominal infection, mycotic aneurysm associated with, 12:34 Intracardiac shunts. See Shunts. Intramural hematoma. See Aortic intramural hematoma. Ipsilateral double aortic arch. See Persistent 5th arch. Iron overload syndrome, 7:58, 7:59, 7:60, 7:61 associated abnormalities, 7:60 clinical issues, 7:60 differential diagnosis, 7:60 genetics, 7:60 imaging, 7:4, 7:58, 7:59, 7:61 pathology, 7:60 suggested protocols by indication, 1:10 Ischemia, nontransmural myocardial infarction vs., 8:91, 8:92 Ischemia right coronary artery stenosis, 8:54, 8:55, 8:56, 8:57

Diagnostic Imaging Cardiovascular clinical issues, 8:56 differential diagnosis, 8:56 imaging, 8:54, 8:55, 8:56, 8:57 pathology, 8:56 Ischemic cardiomyopathy. See Cardiomyopathy, ischemic. Ischemic heart disease, suggested protocols by indication, 1:10 Ischemic stroke, acute, 14:6, 14:7, 14:8, 14:9, 14:10, 14:11 associated abnormalities, 14:8 clinical issues, 14:8 differential diagnosis, 14:8 imaging, 14:6, 14:7, 14:8, 14:9, 14:10, 14:11 pathology, 14:8 subclavian artery stenosis/occlusion associated with, 16:10 Isomerism, right/left. See Heterotaxia syndromes. Ivemark syndrome. See Heterotaxia syndromes.

J > Back of Book > Index > J J Jatene arterial switch procedure, 2:4

K Kawasaki disease coronary fistula vs., 8:132 coronary thrombosis vs., 8:43 Kommerell diverticulum, ductus diverticulum vs., 12:74 Kussmaul-Maier disease. See Polyarteritis nodosa.

L L-transposition of great arteries. See Transposition of great arteries. Laminar flow artifact, acute pulmonary embolism vs., 11:16 Large-vessel vasculitis. See Takayasu arteritis. Lecompte maneuver, 2:4 Left anterior descending coronary artery distribution infarction clinical issues, 8:76 differential diagnosis, 8:76 imaging, 8:75, 8:76, 8:77 infarction, 8:74, 8:75, 8:76, 8:77 pathology, 8:76 Left anterior descending coronary artery occlusion, benign anomalous left coronary artery vs., 8:19 P.xviii

Left atrial appendage, surgical exclusion of, left atrial thrombus vs., 10:19 Left atrial inflow obstruction, other reasons, rheumatic heart disease vs., 4:79

Left atrial thrombus, 10:18, 10:19, 10:20, 10:21 associated abnormalities, 10:20 clinical issues, 10:20 differential diagnosis, 10:19 imaging, 10:18, 10:19, 10:21 pathology, 10:20 Left atrium, anatomy CT, 1:35 graphic, 1:26 morphologic, imaging clues for identifying, 1:16 structure and function, 1:15 Left circumflex coronary artery, anomalous. See Anomalous left circumflex coronary artery. Left coronary artery, anomalous, malignant, 8:16, 8:17 benign anomalous left coronary artery vs., 8:19 differential diagnosis, 8:17 Left flank pain, nutcracker syndrome associated with, 13:35 Left heart failure, 9:10, 9:11, 9:12, 9:13 clinical issues, 9:12 differential diagnosis, 9:11, 9:12 genetics, 9:12 imaging, 9:10, 9:11, 9:13 isolated, right heart failure vs., 9:8 L-transposition of great arteries vs., 2:41 pathology, 9:12 staging, grading, & classification, 9:12 tricuspid valve regurgitation associated with, 4:52 Left main coronary artery, occlusion, benign anomalous left coronary artery vs., 8:19 Left main coronary stenosis, 8:58, 8:59, 8:60, 8:61 clinical issues, 8:60 differential diagnosis, 8:59 imaging, 8:58, 8:59, 8:61 pathology, 8:60 Left pulmonary artery sling, double aortic arch vs., 2:17 Left superior intercostal vein, partial anomalous pulmonary venous return vs., 3:35 Left superior vena cava, persistent, 13:22, 13:23, 13:24, 13:25 clinical issues, 13:23, 13:24 differential diagnosis, 13:23 imaging, 13:22, 13:23, 13:25 partial anomalous pulmonary venous return vs., 3:35 pathology, 13:23, 13:24 pseudocoarctation associated with, 12:66 with absent right superior vena cava, superior vena cava syndrome vs., 13:12 Left ventricle dysfunction, following heart transplantation, differential diagnosis, 9:16

13

hypertrabeculation. See Left ventricular noncompaction. thrombus, left ventricular noncompaction vs., 7:51 transient apical ballooning. See Takotsubo cardiomyopathy. Left ventricle, anatomy graphic, 1:27 morphologic, imaging clues for identifying, 1:16 structure and function, 1:15 Left ventricular aneurysm, absent pericardium vs., 5:35 Left ventricular aneurysm, postinfarction, 8:96, 8:97, 8:98, 8:99 clinical issues, 8:98 differential diagnosis, 8:97, 8:98 imaging, 8:96, 8:97, 8:99 pathology, 8:98 Left ventricular apical aortic conduit, 4:82, 4:83, 4:84, 4:85 clinical issues, 4:83 differential diagnosis, 4:83 imaging, 4:82, 4:83, 4:84, 4:85 pathology, 4:83 Left ventricular failure. See Left heart failure. Left ventricular free wall rupture, 8:106, 8:107, 8:108, 8:109 clinical issues, 8:107 differential diagnosis, 8:107 imaging, 8:106, 8:107, 8:108, 8:109 pathology, 8:107 staging, grading, & classification, 8:107 Left ventricular hypertrophy, 9:22, 9:23 Left ventricular inflow obstruction, tricuspid valve regurgitation associated with, 4:52 Left ventricular noncompaction, 7:50, 7:51, 7:52, 7:53 associated abnormalities, 7:51, 7:52 clinical issues, 7:52 differential diagnosis, 7:51 genetics, 7:51 hypereosinophilic syndrome vs., 7:38 imaging, 7:3, 7:50, 7:51, 7:53 or prominent normal trabeculation, cardiac thrombus vs., 6:26 pathology, 7:51, 7:52 Left ventricular outflow tract obstruction L-transposition of great arteries associated with, 2:42 left ventricular noncompaction associated with, 7:51 Left ventricular pseudoaneurysm, postinfarction, 8:100, 8:101, 8:102, 8:103 clinical issues, 8:101 differential diagnosis, 8:101 imaging, 8:100, 8:101, 8:102, 8:103 pathology, 8:101 Leiomyoma, lymphoma vs., 6:58 Leiomyosarcoma, tumor extension into atria vs., 6:14 P.xix

Diagnostic Imaging Cardiovascular

Leriche syndrome. See Aortic occlusion, abdominal. Levo transposition of great arteries. See Transposition of great arteries. Lipoma, cardiac, 6:20, 6:21, 6:22, 6:23 cardiac sarcoma vs., 6:31 clinical issues, 6:22 differential diagnosis, 6:21, 6:22 imaging, 6:20, 6:21, 6:23 lipomatous hypertrophy of interatrial septum vs., 6:51 lymphoma vs., 6:58 osteoarthritis, 6:22 Lipomatous hypertrophy, interatrial septum, 6:50, 6:51, 6:52, 6:53, 6:54, 6:55 cardiac lipoma vs., 6:22 characteristics, 6:37 clinical issues, 6:52 differential diagnosis, 6:51, 6:52 imaging, 6:50, 6:51, 6:53, 6:54, 6:55 pathology, 6:52 tumor mimics vs., 6:38 Liposarcoma cardiac lipoma vs., 6:21, 6:22 lipomatous hypertrophy of interatrial septum vs., 6:51 Lobar emphysema (or hyperinflation), congenital, pulmonary sling vs., 2:31 Löffler endocarditis. See Endomyocardial fibrosis. Löffler myocarditis. See Hypereosinophilic syndrome. Lower extremity anatomy, 16:4, 16:5, 16:6, 16:7 anatomy imaging issues, 16:4 imaging anatomy, 16:4 lower extremity arterial anatomy, 16:5, 16:6 pelvic and lower extremity arterial anatomy, 16:5 upper and lower extremity venous anatomy, 16:7 Lower extremity aneurysms, 16:24, 16:25, 16:26, 16:27 associated abnormalities, 16:26 clinical issues, 16:26 differential diagnosis, 16:25, 16:26 imaging, 16:24, 16:25, 16:27 pathology, 16:26 Lower extremity arteriovenous fistula, 16:42, 16:43, 16:44, 16:45 clinical issues, 16:44 differential diagnosis, 16:43, 16:44 genetics, 16:44 imaging, 16:42, 16:43, 16:45 pathology, 16:44 Lower extremity deep vein thrombosis, 16:46, 16:47, 16:48, 16:49 clinical issues, 16:48 differential diagnosis, 16:48 genetics, 16:48 imaging, 16:46, 16:47, 16:49 pathology, 16:48

Lower extremity ischemia, acute, 16:28, 16:29, 16:30, 16:31 clinical issues, 16:30 differential diagnosis, 16:29, 16:30 imaging, 16:28, 16:29, 16:31 pathology, 16:30 staging, grading, & classification, 16:30 Lower extremity peripheral vasculature, 16:24, 16:25, 16:26, 16:27, 16:28, 16:29, 16:30, 16:31, 16:32, 16:33, 16:34, 16:35, 16:36, 16:37, 16:38, 16:39, 16:40, 16:41, 16:42, 16:43, 16:44, 16:45, 16:46, 16:47, 16:48, 16:49 acute lower extremity ischemia, 16:28, 16:29, 16:30, 16:31 anatomy, 16:4, 16:5, 16:6, 16:7 aneurysms. See Lower extremity aneurysms. arteriovenous fistula, 16:42, 16:43, 16:44, 16:45 cystic adventitial disease. See Cystic adventitial disease. deep vein thrombosis, 16:46, 16:47, 16:48, 16:49 femoropopliteal artery occlusive disease, 16:32, 16:33, 16:34, 16:35 persistent sciatic artery, 16:40, 16:41 Lung abscess, pulmonary sequestration vs., 11:24 Lung cancer, pulmonary sequestration vs., 11:24 Lung disease, chronic, tricuspid valve regurgitation associated with, 4:52 Lupus/anticardiolipin antibodies, chronic pulmonary embolism associated with, 11:20 Lupus erythematosus. See Systemic lupus erythematosus. Lymphangioma, hemangioma vs., 6:42 Lymphoma, 6:56, 6:57, 6:58, 6:59 cardiac sarcoma vs., 6:31 clinical issues, 6:58 differential diagnosis, 6:57, 6:58 imaging, 6:56, 6:57, 6:59 pathology, 6:58

M Marfan syndrome, 12:60, 12:61, 12:62, 12:63 aortic dissection vs., 12:50 carotid dissection associated with, 14:22 clinical issues, 12:61 differential diagnosis, 12:61 genetics, 12:61 imaging, 12:60, 12:61, 12:62, 12:63 mitral valve prolapse vs., 4:30 mitral valve regurgitation associated with, 4:33 multivalvular disease vs., 4:73 pathology, 12:61 pulmonary valve regurgitation vs., 4:45 renal fibromuscular dysplasia vs., 15:18

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vertebral artery dissection associated with, 14:30 May-Thurner syndrome, 13:30, 13:31, 13:32, 13:33 associated abnormalities, 13:32 clinical issues, 13:32 differential diagnosis, 13:31, 13:32 imaging, 13:30, 13:31, 13:33 inferior vena cava occlusion associated with, 13:20 pathology, 13:32 staging, grading, & classification, 13:32 Meckel diverticulum, pulmonary sling associated with, 2:32 P.xx

Mediastinal mass chronic post-traumatic aortic pseudoaneurysm vs., 12:37 double aortic arch vs., 2:17 middle, pulmonary sling vs., 2:31 pseudocoarctation vs., 12:66 right aortic arch vs., 2:23 thoracic aortic aneurysm vs., 12:27 Mediastinum, widened, traumatic aortic laceration vs., 12:70 Medications. See Drug therapy. Mesothelioma, lipomatous hypertrophy of interatrial septum vs., 6:52 Metabolic disorders, infectious pericarditis vs., 5:17 Metastatic disease, 6:8, 6:9, 6:10, 6:11 associated abnormalities, 6:10 cardiac, atrial myxoma vs., 6:17 cardiac lipoma vs., 6:22 cardiac sarcoma vs., 6:31 clinical issues, 6:10 differential diagnosis, 6:10 fibroma vs., 6:47 hemangioma vs., 6:41, 6:42 imaging, 6:8, 6:9, 6:10, 6:11 left atrial thrombus vs., 10:19 lipomatous hypertrophy of interatrial septum vs., 6:52 lymphoma vs., 6:57 pathology, 6:10 pulmonary arteriovenous malformations vs., 11:7 Methysergide, rheumatic heart disease vs., 4:79 Microscopic polyangiitis, polyarteritis nodosa vs., 15:21 Mid-aortic (coarctation) syndrome, abdominal aortic occlusion vs., 12:89 Mitral annular carcinoma, caseous, mitral valve annular calcification vs., 4:37 Mitral valve annulus, dilated, papillary muscle rupture vs., 8:79 insufficiency. See Mitral valve regurgitation. obstruction, mitral stenosis vs., 4:25

Diagnostic Imaging Cardiovascular primary flail leaflets, mitral valve regurgitation vs., 4:33 trauma, mitral valve prolapse vs., 4:30 Mitral valve abnormalities atrial septal defects associated with, 3:12 truncus arteriosus associated with, 2:46 Mitral valve, anatomy anatomy, 1:15 CT of mitral valve, 1:55 echocardiography, aortic and mitral valves, 1:52 radiography of prosthetic aortic and mitral valves, 1:46 Mitral valve annular calcification, 4:36, 4:37, 4:38, 4:39 associated abnormalities, 4:37 characteristics, 6:37 clinical issues, 4:38 coronary artery calcification vs., 8:33 differential diagnosis, 4:37 genetics, 4:37 imaging, 4:36, 4:37, 4:39 pathology, 4:37, 4:38 tumor mimics vs., 6:38 Mitral valve disease degenerative, mitral valve regurgitation vs., 4:33 myxomatous, mitral valve prolapse vs., 4:30 Mitral valve prolapse, 4:28, 4:29, 4:30, 4:31 clinical issues, 4:30 coronary artery stenosis vs., 8:50 differential diagnosis, 4:30 imaging, 4:28, 4:29, 4:31 pathology, 4:30 Mitral valve regurgitation, 4:32, 4:33, 4:34, 4:35 clinical issues, 4:34 differential diagnosis, 4:33 genetics, 4:33 imaging, 4:32, 4:33, 4:35 ischemic, 4:33 papillary muscle rupture vs., 8:79 other causes, post-infarction mitral valve regurgitation vs., 8:105 pathology, 4:33, 4:34 post infarction, 8:104, 8:105 secondary, rheumatic heart disease vs., 4:79 severe, dilated nonischemic cardiomyopathy vs., 7:20 staging, grading, & classification, 4:33, 4:34 Mitral valve stenosis, 4:24, 4:25, 4:26, 4:27 associated abnormalities, 4:25 clinical issues, 4:26 congenital, mitral stenosis vs., 4:25 differential diagnosis, 4:25 imaging, 4:24, 4:25, 4:27 pathology, 4:25, 4:26 staging, grading, & classification, 4:26

Morgagni hernia, pericardial cyst vs., 5:31 Mucopolysaccharidoses mitral stenosis vs., 4:25 rheumatic heart disease vs., 4:79 Multivalvular disease, 4:72, 4:73, 4:74, 4:75, 4:76, 4:77 calcific, mitral valve annular calcification vs., 4:37 clinical issues, 4:73 differential diagnosis, 4:73 imaging, 4:72, 4:73, 4:74, 4:75, 4:76, 4:77 Musculoskeletal diseases of chest wall or shoulders, ischemia right coronary artery stenosis vs., 8:56 Mycotic aortic aneurysm, 12:32, 12:33, 12:34, 12:35 abdominal aortic aneurysm with rupture vs., 12:83 differential diagnosis, 12:33 Mycotic pseudoaneuysm, penetrating aortic atherosclerotic ulcer vs., 12:45 P.xxi

Myocardial bridge, 8:128, 8:129 clinical issues, 8:129 coronary atherosclerotic plaque vs., 8:38 differential diagnosis, 8:129 imaging, 8:128, 8:129 pathology, 8:129 staging, grading, & classification, 8:129 Myocardial calcification, constrictive pericarditis vs., 5:28 Myocardial infarction acute. See Myocardial infarction, acute. chronic, 8:70, 8:71, 8:72, 8:73 differential diagnosis, 8:72 imaging, 8:70, 8:71, 8:72, 8:73 infectious pericarditis vs., 5:17, 5:18 lipomatous hypertrophy of interatrial septum vs., 6:51 nonatherosclerotic, 8:86, 8:87, 8:88, 8:89 differential diagnosis, 8:87 imaging, 8:86, 8:87, 8:89 nontransmural, 8:90, 8:91, 8:92, 8:93, 8:94, 8:95 differential diagnosis, 8:91, 8:92 imaging, 8:90, 8:91, 8:93, 8:94, 8:95 old acute myocardial infarction vs., 8:68 calcification of, coronary artery calcification vs., 8:33 post-infarction left ventricular aneurysm, 8:96, 8:97, 8:98, 8:99 subclavian artery stenosis/occlusion associated with, 16:10 subendocardial, post-infarction left ventricular aneurysm vs., 8:97 transmural, nontransmural myocardial infarction vs., 8:91, 8:92 uremic pericarditis vs., 5:21

15

Myocardial infarction, acute, 8:66, 8:67, 8:68, 8:69 chronic myocardial infarction vs., 8:72 clinical issues, 8:68 differential diagnosis, 8:68 due to atherosclerotic coronary artery disease, coronary embolism vs., 8:29 imaging, 8:66, 8:67, 8:68, 8:69 pathology, 8:68 post-infarction left ventricular aneurysm vs., 8:97 sarcoidosis vs., 7:44 Takotsubo cardiomyopathy vs., 7:63 Myocarditis, 7:26, 7:27, 7:28, 7:29 acute. See Myocarditis, acute. arrhythmogenic right ventricular dysplasia/cardiomyopathy vs., 7:32 chronic, ischemic cardiomyopathy vs., 7:16 clinical issues, 7:28 coronary embolism vs., 8:29 differential diagnosis, 7:27, 7:28 eosinophilic. See Hypereosinophilic syndrome. imaging, 7:3, 7:26, 7:27, 7:29 Löffler myocarditis. See Hypereosinophilic syndrome. nontransmural myocardial infarction vs., 8:91 pathology, 7:28 sarcoidosis vs., 7:44 staging, grading, & classification, 7:28 viral, Chagas disease vs., 7:55 Myocarditis, acute acute myocardial infarction vs., 8:68 coronary artery stenosis vs., 8:50 infarction, left anterior descending distribution vs., 8:76 ischemia right coronary artery stenosis vs., 8:56 nonatherosclerotic myocardial infarction vs., 8:87 Takotsubo cardiomyopathy vs., 7:63 Myocarditis/sarcoid, suggested protocols by indication, 1:10 Myocardium hibernating, post-infarction left ventricular aneurysm vs., 8:98 noncompaction, endomyocardial fibrosis vs., 7:36 spongy. See Left ventricular noncompaction. Myopericarditis metastatic disease vs., 6:10 neoplastic pericarditis vs., 5:24 Myxoma atrial. See Atrial myxoma. cardiac sarcoma vs., 6:31 fibroma vs., 6:48 hemangioma vs., 6:41 lipomatous hypertrophy of interatrial septum vs., 6:51 lymphoma vs., 6:58 rheumatic heart disease vs., 4:79 tumor extension into atria vs., 6:14 Myxomatous mitral valve disease

Diagnostic Imaging Cardiovascular mitral valve prolapse vs., 4:30 mitral valve regurgitation vs., 4:33

N Neoplastic disease, 6:2, 6:3, 6:4, 6:5, 6:6, 6:7, 6:8, 6:9, 6:10, 6:11, 6:12, 6:13, 6:14, 6:15, 6:16, 6:17, 6:18, 6:19, 6:20, 6:21, 6:22, 6:23, 6:24, 6:25, 6:26, 6:27, 6:28, 6:29, 6:30, 6:31, 6:32, 6:33, 6:34, 6:35, 6:36, 6:37, 6:38, 6:39, 6:40, 6:41, 6:42, 6:43, 6:44, 6:45, 6:46, 6:47, 6:48, 6:49, 6:50, 6:51, 6:52, 6:53, 6:54, 6:55, 6:56, 6:57, 6:58, 6:59 See also Metastatic disease. approach to. See Neoplastic disease, approach to. atrial myxoma. See Atrial myxoma. benign, cardiac thrombus vs., 6:25 bronchogenic carcinoma, pericardial cyst vs., 5:32 carcinoid tumor. See also Carcinoid syndrome. malignant, mitral stenosis vs., 4:25 pulmonary artery pseudoaneurysm vs., 11:9 cardiac tumor, primary malignant, atrial myxoma vs., 6:17 carotid space schwannoma, carotid dissection vs., 14:21 P.xxii

extracardiac, carcinoid syndrome vs., 4:70 fibroma. See Fibroma. hemangioma. See Hemangioma. history of, chronic pulmonary embolism associated with, 11:20 hypervascular, pulmonary artery pseudoaneurysm vs., 11:9 infectious pericarditis vs., 5:18 leiomyoma, lymphoma vs., 6:58 leiomyosarcoma, tumor extension into atria vs., 6:14 lipoma, cardiac, 6:20, 6:21, 6:22, 6:23 lipomatous hypertrophy, interatrial septum. See Lipomatous hypertrophy, interatrial septum. liposarcoma cardiac lipoma vs., 6:21, 6:22 lipomatous hypertrophy of interatrial septum vs., 6:51 lower extremity aneurysms vs., 16:25 lung, pulmonary sequestration vs., 11:24 lymphangioma, hemangioma vs., 6:42 lymphoma. See Lymphoma. malignant, primary, metastatic disease vs., 6:10 mediastinal mass. See Mediastinal mass. mesothelioma, lipomatous hypertrophy of interatrial septum vs., 6:52

mitral annular carcinoma, caseous, mitral valve annular calcification vs., 4:37 myocardial bridge vs., 8:129 myxoma. See Atrial myxoma; Myxoma. neurofibroma, pericardial cyst vs., 5:32 neurofibromatosis coarctation of aorta vs., 2:11 renal fibromuscular dysplasia vs., 15:18 neurogenic mass, persistent sciatic artery vs., 16:41 papillary fibroelastoma, 6:44, 6:45 differential diagnosis, 6:45 mitral stenosis vs., 4:25 paraganglioma fibroma vs., 6:48 glomus vagale, carotid dissection vs., 14:21 hemangioma vs., 6:41, 6:42 pelvic tumors, May-Thurner syndrome vs., 13:32 pericardial masses, approach to, 5:3, 5:4 pericardial tumors. See Pericardial tumors. pericarditis, neoplastic, 5:22, 5:23, 5:24, 5:25 popliteal fossa mass, cystic adventitial disease vs., 16:38 primary malignancy, left atrial thrombus vs., 10:19 primary or secondary malignancy, cardiac thrombus vs., 6:25 renal, renal arteriovenous fistula vs., 15:25 renal vascular tumor, nutcracker syndrome vs., 13:35 renal vein tumor extension, renal vein thrombosis vs., 15:29 rhabdomyoma. See Rhabdomyoma. rhabdomyosarcoma fibroma vs., 6:47 mitral stenosis vs., 4:25 right atrium tumor, carcinoid syndrome vs., 4:70 sarcoma cardiac. See Sarcoma, cardiac. pulmonary artery acute pulmonary embolism vs., 11:16 chronic pulmonary embolism vs., 11:20 soft tissue, persistent sciatic artery vs., 16:41 suggested protocols by indication, 1:10 teratoma. See Teratoma. thrombus, cardiac. See Thrombus, cardiac. thymolipoma, pericardial cyst vs., 5:32 tumor extension into atria, 6:12, 6:13, 6:14, 6:15 tumor mimics, 6:36, 6:37, 6:38, 6:39 tumor thrombus/embolus acute pulmonary embolism vs., 11:16 subclavian vein thrombosis vs., 16:14 vascular, lower extremity arteriovenous fistula vs., 16:43

16

Neoplastic disease, approach to, 6:2, 6:3, 6:4, 6:5, 6:6, 6:7 cardiac masses by location, 6:4 comparison of imaging modalities, 6:4 differential diagnosis, 6:3 epicardial/pericardial lesions, 6:3 images, 6:5, 6:6, 6:7 imaging considerations, 6:2 intracavitary lesions, 6:2, 6:3 intramural lesions benign, 6:3 in children, 6:3 malignant, 6:3 introduction, 6:2 suggested MR protocol, 6:4 tumor mimics/pseudomasses, 6:3 valvular lesions, 6:3 Neoplastic pericarditis, 5:22, 5:23, 5:24, 5:25 Nephrotic syndrome, adult, renal vein thrombosis associated with, 15:30 Neurofibroma, pericardial cyst vs., 5:32 Neurofibromatosis coarctation of aorta vs., 2:11 renal fibromuscular dysplasia vs., 15:18 Neurogenic mass, persistent sciatic artery vs., 16:41 Nodules of Arantius, papillary fibroelastoma vs., 6:45 Nonischemic dilated cardiomyopathy. See Cardiomyopathy, nonischemic dilated. Noonan syndrome, pulmonary valve stenosis associated with, 4:42 Norwood procedure, 2:4 Nutcracker syndrome, 13:34, 13:35, 13:36, 13:37 associated abnormalities, 13:35, 13:36 P.xxiii

clinical issues, 13:36 differential diagnosis, 13:35 imaging, 13:34, 13:35, 13:37 pathology, 13:35, 13:36 renal arteriovenous fistula vs., 15:26 renal vein thrombosis vs., 15:30

O Osseous fractures, chronic posttraumatic aortic pseudoaneurysm associated with, 12:37 Osteogenesis imperfecta carotid dissection associated with, 14:22 mitral valve prolapse vs., 4:30

P Pacemakers/implantable cardioverterdefibrillators, 10:12, 10:13, 10:14, 10:15 clinical issues, 10:14 differential diagnosis, 10:14 imaging, 10:12, 10:13, 10:15

Diagnostic Imaging Cardiovascular pathology, 10:14 Pancreatic pseudocyst, pericardial cyst vs., 5:32 Pannus. See Valvular pannus. Papillary fibroelastoma, 6:44, 6:45 differential diagnosis, 6:45 imaging, 6:44, 6:45 mitral stenosis vs., 4:25 Papillary muscle rupture, 8:78, 8:79, 8:80, 8:81 clinical issues, 8:80 differential diagnosis, 8:79, 8:80 imaging, 8:78, 8:79, 8:81 pathology, 8:80 Papillary muscles, cardiac thrombus vs., 6:26 Paraganglioma fibroma vs., 6:48 glomus vagale, carotid dissection vs., 14:21 hemangioma vs., 6:41, 6:42 Parenchymal hypodensity (nonvascular causes), acute ischemic stroke vs., 14:8 Partial anomalous pulmonary venous return. See Pulmonary venous return, partial anomalous. Patent Botallo duct. See Patent ductus arteriosus. Patent ductus arteriosus, 3:4, 3:5, 3:6, 3:7, 3:8, 3:9 atrial septal defects vs., 3:11 bicuspid aortic valve associated with, 4:22 clinical issues, 3:6 coarctation of aorta associated with, 2:12 differential diagnosis, 3:5 endocardial cushion defect vs., 3:23 genetics, 3:5 imaging, 3:4, 3:5, 3:7, 3:8, 3:9 pathology, 3:5, 3:6 persistent, ductus diverticulum associated with, 12:74 persistent 5th arch vs., 2:29 pseudocoarctation associated with, 12:66 pulmonary sling associated with, 2:32 Scimitar syndrome associated with, 3:27 staging, grading, & classification, 3:6 ventricular septal defects vs., 3:17 Patent foramen ovale atrial septal defects vs., 3:11 pulmonary valve stenosis associated with, 4:42 Pelvic tumors, May-Thurner syndrome vs., 13:32 Pelvic varicosities/pelvic congestion, female, nutcracker syndrome associated with, 13:35 Penetrating aortic atherosclerotic ulcer, 12:44, 12:45, 12:46, 12:47 aortic dissection vs., 12:50 approach to, 12:4 differential diagnosis, 12:45

Pentalogy of Fallot, tetralogy of Fallot vs., 2:71 Peptic ulcer coronary artery stenosis vs., 8:50 ischemia right coronary artery stenosis vs., 8:56 Percutaneous aortic valve replacement. See Aortic valve replacement, transcatheter. Periaortitis, aortic graft complications vs., 12:87 Pericardial anatomy, 5:8, 5:9, 5:10, 5:11, 5:12, 5:13, 5:14, 5:15 anatomy imaging issues, 5:8 axial MDCT, 5:12, 5:13 black blood MR, 5:14 cross-sectional appearance, 5:11 gross anatomy, 5:8 fibrous pericardium, 5:8 pericardial attachments, 5:8 pericardial sinuses, 5:8 pericardiophrenic bundle, 5:8 serous pericardium, 5:8 imaging anatomy, 5:8 pericardial sac, with and without heart, 5:9 visceral pericardium, posterior view, parietal pericardium removed, 5:10 white blood cine & LGE imaging, 5:15 Pericardial calcification, coronary artery calcification vs., 8:33 Pericardial cyst, 5:30, 5:31, 5:32, 5:33 absent pericardium vs., 5:35 approach to, 5:3, 5:4 clinical issues, 5:32 differential diagnosis, 5:31, 5:32 imaging, 5:30, 5:31, 5:33 neoplastic pericarditis vs., 5:24 pathology, 5:32 pericardial effusion vs., 5:38 post-infarction left ventricular pseudoaneurysm vs., 8:101 Pericardial disease, 5:2, 5:3, 5:4, 5:5, 5:6, 5:7, 5:8, 5:9, 5:10, 5:11, 5:12, 5:13, 5:14, 5:15, 5:16, 5:17, 5:18, 5:19, 5:20, 5:21, 5:22, 5:23, 5:24, 5:25, 5:26, 5:27, 5:28, 5:29, 5:30, 5:31, 5:32, 5:33, 5:34, 5:35, 5:36, 5:37, 5:38, 5:39, 5:40, 5:41, 5:42, 5:43, 5:44, 5:45 absent pericardium. See Pericardium, absent. approach to. See Pericardial disease, approach to. constrictive pericarditis. See Pericarditis, constrictive. infectious pericarditis, 5:16, 5:17, 5:18, 5:19 neoplastic pericarditis, 5:22, 5:23, 5:24, 5:25 pericardial cyst. See Pericardial cyst. P.xxiv

pericardial effusion. See Pericardial effusion.

17

pericardial tamponade. See Pericardial tamponade. uremic pericarditis, 5:20, 5:21 Pericardial disease, approach to, 5:2, 5:3, 5:4, 5:5, 5:6, 5:7 choice of imaging test, 5:2 congenital absence of pericardium, 5:4 images, 5:5, 5:6, 5:7 imaging modalities, 5:4 introduction, 5:2 pericardial effusion and cardiac tamponade, 5:2 pericardial masses, 5:3, 5:4 pericarditis, 5:2, 5:3 Pericardial effusion, 5:36, 5:37, 5:38, 5:39, 5:40, 5:41 absent pericardium vs., 5:35 approach to, 5:2 clinical issues, 5:38 differential diagnosis, 5:38 Ebstein anomaly vs., 2:63 fibrinous, pericardial tamponade vs., 5:44 hemorrhagic, pericardial tamponade vs., 5:44 imaging, 5:36, 5:37, 5:38, 5:39 left heart failure vs., 9:12 left ventricular free wall rupture vs., 8:107 lymphatic, pericardial tamponade vs., 5:44 malignant, metastatic disease associated with, 6:10 pathology, 5:38 serous, pericardial tamponade vs., 5:43 Pericardial fat pad, pericardial cyst vs., 5:31 Pericardial hematoma, left ventricular free wall rupture vs., 8:107 Pericardial lymph nodes, enlarged, pericardial cyst vs., 5:32 Pericardial masses, approach to, 5:3, 5:4 Pericardial tamponade, 5:42, 5:43, 5:44, 5:45 acute, right ventricular infarction vs., 8:84 approach to, 5:2 clinical issues, 5:44 constrictive pericarditis vs., 5:28 differential diagnosis, 5:43, 5:44 imaging, 5:42, 5:43, 5:45 pathology, 5:44 Pericardial tumors approach to, 5:4 constrictive pericarditis vs., 5:28 malignant, pericardial effusion vs., 5:38 metastases, pericardial cyst vs., 5:32 teratoma, cardiac lipoma vs., 6:21 uremic pericarditis vs., 5:21 Pericarditis acute acute myocardial infarction vs., 8:68 right ventricular infarction vs., 8:84 approach to, 5:2, 5:3

Diagnostic Imaging Cardiovascular constrictive. See Pericarditis, constrictive. coronary artery stenosis vs., 8:50 iatrogenic, infectious pericarditis vs., 5:17 idiopathic, infectious pericarditis vs., 5:17 infectious, 5:16, 5:17, 5:18, 5:19 differential diagnosis, 5:17, 5:18 imaging, 5:16, 5:17, 5:19 inflammatory, infectious pericarditis vs., 5:17 neoplastic, 5:22, 5:23, 5:24, 5:25 differential diagnosis, 5:23, 5:24 imaging, 5:22, 5:23, 5:25 nonconstrictive approach to, 5:2, 5:3 constrictive pericarditis vs., 5:28 other causes, uremic pericarditis vs., 5:21 uremic, 5:20, 5:21 Pericarditis, constrictive, 5:26, 5:27, 5:28, 5:29 approach to, 5:3 chronic myocardial infarction vs., 8:72 clinical issues, 5:28 differential diagnosis, 5:28 effusive constrictive, approach to, 5:3 endomyocardial fibrosis vs., 7:35, 7:36 imaging, 5:26, 5:27, 5:28, 5:29 pathology, 5:28 restrictive cardiomyopathy vs., 7:23 right heart failure vs., 9:8 Pericardium, absent, 5:34, 5:35 congenital, approach to, 5:4 differential diagnosis, 5:35 imaging, 5:34, 5:35 left, Scimitar syndrome associated with, 3:27 staging, grading, & classification, 5:35 Pericardium, suggested protocols by indication, 1:10 Perioperative infarction, post-coronary artery bypass graft thrombosis vs., 8:121 Peripheral artery disease, cystic adventitial disease vs., 16:37 Peripheral vasculature, approach to, 16:2, 16:3 aneurysms, 16:2 pathologic issues, 16:2 pathology-based imaging issues, 16:2, 16:3 peripheral arterial disease, 16:2 thromboembolic disease, 16:2 Peripheral vasculature, lower extremity, 16:24, 16:25, 16:26, 16:27, 16:28, 16:29, 16:30, 16:31, 16:32, 16:33, 16:34, 16:35, 16:36, 16:37, 16:38, 16:39, 16:40, 16:41, 16:42, 16:43, 16:44, 16:45, 16:46, 16:47, 16:48, 16:49 acute lower extremity ischemia, 16:28, 16:29, 16:30, 16:31 anatomy, 16:4, 16:5, 16:6, 16:7 aneurysms, 16:24, 16:25, 16:26, 16:27

arteriovenous fistula, 16:42, 16:43, 16:44, 16:45 cystic adventitial disease. See Cystic adventitial disease. deep vein thrombosis, 16:46, 16:47, 16:48, 16:49 femoropopliteal artery occlusive disease, 16:32, 16:33, 16:34, 16:35 persistent sciatic artery, 16:40, 16:41 Peripheral vasculature, trunk, 16:8, 16:9, 16:10, 16:11, 16:12, 16:13, 16:14, 16:15, 16:16, 16:17, 16:18, 16:19, 16:20, 16:21, 16:22, 16:23 iliac artery aneurysmal disease, 16:20, 16:21, 16:22, 16:23 differential diagnosis, 16:21, 16:22 iliac artery occlusive disease vs., 16:17 iliac artery occlusive disease, 16:16, 16:17, 16:18, 16:19 P.xxv

subclavian artery stenosis/occlusion, 16:8, 16:9, 16:10, 16:11 subclavian vein thrombosis, 16:12, 16:13, 16:14, 16:15 Permanent pacing device. See Pacemakers/implantable cardioverterdefibrillators. Persistent arterial duct. See Patent ductus arteriosus. Persistent fetal circulation syndrome patent ductus arteriosus vs., 3:5 total anomalous pulmonary venous return vs., 3:31 Persistent 5th arch, 2:28, 2:29 Persistent left superior vena cava. See Left superior vena cava, persistent. Persistent sciatic artery, 16:40, 16:41 Persistent superior vena cava, ± coronary sinus ASD, pulmonary sling associated with, 2:32 Phentermine usage, carcinoid syndrome vs., 4:70 Phrenic cyst, Scimitar syndrome associated with, 3:27 Plakophilin mutation, arrhythmogenic right ventricular dysplasia/cardiomyopathy associated with, 7:32 Pleural effusion, loculated absent pericardium vs., 5:35 pericardial cyst vs., 5:31 Pneumonia postobstructive, pulmonary sequestration vs., 11:24 pulmonary sequestration vs., 11:23 Polyangiitis, microscopic, polyarteritis nodosa vs., 15:21 Polyarteritis nodosa, 15:20, 15:21, 15:22, 15:23 clinical issues, 15:22 differential diagnosis, 15:21 imaging, 15:20, 15:21, 15:23 pathology, 15:22 renal artery atherosclerosis vs., 15:13

18

Polycystic kidney disease, autosomal dominant carotid dissection associated with, 14:22 vertebral artery dissection associated with, 14:30 Polysplenia, azygos continuation of inferior vena cava associated with, 13:28 Popliteal artery aneurysms acute lower extremity ischemia vs., 16:30 cystic adventitial disease vs., 16:37 lower extremity aneurysms associated with, 16:26 Popliteal artery embolus, cystic adventitial disease vs., 16:37 Popliteal artery entrapment acute lower extremity ischemia vs., 16:30 cystic adventitial disease vs., 16:37 femoropopliteal artery occlusive disease vs., 16:34 lower extremity aneurysms vs., 16:25 Post-angioplasty dissection, postangioplasty restenosis vs., 8:113 Post-angioplasty restenosis, 8:112, 8:113 Post-coronary artery bypass graft atherosclerosis, 8:124, 8:125, 8:126, 8:127 clinical issues, 8:126 differential diagnosis, 8:125 imaging, 8:124, 8:125, 8:127 post-coronary artery bypass graft thrombosis vs., 8:121 Post-coronary artery bypass graft thrombosis, 8:120, 8:121, 8:122, 8:123 clinical issues, 8:122 differential diagnosis, 8:121 imaging, 8:120, 8:121, 8:123 pathology, 8:121, 8:122 post-coronary artery bypass graft atherosclerosis vs., 8:125 Post-endovascular stent, aortic graft complications vs., 12:87 Post-infarction left ventricular aneurysm, 8:96, 8:97, 8:98, 8:99 Post-infarction left ventricular pseudoaneurysm, 8:100, 8:101, 8:102, 8:103 Post-infarction left ventricular rupture. See Ventricular septal rupture. Post-infarction mitral regurgitation, 8:104, 8:105 Post-intervention, aortic graft complications vs., 12:87 Post-traumatic pseudoaneurysm, chronic, 12:36, 12:37, 12:38, 12:39 Postobstructive pneumonia, pulmonary sequestration vs., 11:24 Postoperative status, aortic graft complications vs., 12:87 Potts shunt, Blalock-Taussig shunt for tetralogy of Fallot vs., 2:77

Diagnostic Imaging Cardiovascular Prosthetic valve, 4:58, 4:59, 4:60, 4:61, 4:62, 4:63 differential diagnosis, 4:60 dysfunction, infective endocarditis vs., 4:55 radiography of prosthetic aortic and mitral valves, 1:46 Prosthetic valve complications, 4:64, 4:65, 4:66, 4:67 Proteinuria, nutcracker syndrome associated with, 13:35 Prothrombotic states, acute ischemic stroke associated with, 14:8 Proximal interruption of pulmonary artery. See Pulmonary artery interruption, proximal. Pseudoaneurysm anastomotic, iliac artery aneurysmal disease vs., 16:21, 16:22 aortic, chronic post-traumatic, 12:36, 12:37, 12:38, 12:39 differential diagnosis, 12:37 ductus diverticulum vs., 12:73 coronary artery, coronary artery aneurysm vs., 8:31 extracranial carotid, 14:24, 14:25, 14:26, 14:27 internal carotid artery, traumatic, carotid dissection vs., 14:21 left ventricular, post-infarction, 8:100, 8:101, 8:102, 8:103 lower extremity aneurysms vs., 16:25, 16:26 post-infarction left ventricular aneurysm vs., 8:97 P.xxvi

post-infarction left ventricular pseudoaneurym, 8:100, 8:101, 8:102, 8:103 pulmonary artery. See Pulmonary artery pseudoaneurysm. traumatic aortic. See Traumatic aortic laceration. traumatic, coarctation of aorta vs., 2:11 Pseudocoarctation, 12:64, 12:65, 12:66, 12:67 associated abnormalities, 12:66 clinical issues, 12:66 coarctation of aorta vs., 2:11 differential diagnosis, 12:65, 12:66 imaging, 12:64, 12:65, 12:67 pathology, 12:66 Pseudolipoma, tumor extension into atria vs., 6:14 Pseudomasses. See Tumor mimics. Pseudothrombosis, tumor extension into atria vs., 6:14 Pseudothrombus, on CTA, left atrial thrombus vs., 10:19 Pseudotruncus. See Pulmonary atresia. Pulmonary airway malformation, congenital, pulmonary sequestration vs., 11:24 Pulmonary arterial banding, 2:3

Pulmonary arterial hypertension, 11:30, 11:31, 11:32, 11:33 atrial septal defects vs., 3:11 branch pulmonary artery stenosis vs., 11:27 clinical issues, 11:32 differential diagnosis, 11:31, 11:32 from severe hypoxia, pulmonary sling associated with, 2:32 idiopathic chronic pulmonary embolism vs., 11:20 pulmonary venoocclusive disease vs., 11:35 imaging, 11:30, 11:31, 11:33 patent ductus arteriosus vs., 3:5 pathology, 11:32 primary, total anomalous pulmonary venous return vs., 3:31 pulmonary valve regurgitation vs., 4:45 pulmonary valve stenosis vs., 4:41 staging, grading, & classification, 11:32 ventricular septal defects vs., 3:17 Pulmonary arterial thromboembolic disease, chronic. See Pulmonary embolism, chronic. Pulmonary arteriovenous malformation, 11:6, 11:7 differential diagnosis, 11:7 imaging, 11:6, 11:7 partial anomalous pulmonary venous return associated with, 3:35 pulmonary artery aneurysm vs., 11:11 pulmonary artery pseudoaneurysm vs., 11:9 Pulmonary artery branch stenosis. See Pulmonary artery pseudoaneurysm. left aberrant, pulmonary valve stenosis vs., 4:41 proximal, atresia of, pulmonary atresia associated with, 2:50 right, absent, Scimitar syndrome associated with, 3:27 stenosis, adult-acquired, branch pulmonary artery stenosis vs., 11:27 Pulmonary artery aneurysm, 11:10, 11:11, 11:12, 11:13 clinical issues, 11:12 differential diagnosis, 11:11 genetics, 11:12 imaging, 11:10, 11:11, 11:13 pathology, 11:11, 11:12 pulmonary artery pseudoaneurysm vs., 11:9 Pulmonary artery interruption, proximal, 2:84, 2:85, 2:86, 2:87 associated abnormalities, 2:85 clinical issues, 2:85 differential diagnosis, 2:85 imaging, 2:84, 2:85, 2:86, 2:87 pathology, 2:85 pulmonary valve stenosis vs., 4:41 Pulmonary artery pseudoaneurysm, 11:8, 11:9 differential diagnosis, 11:9 imaging, 11:8, 11:9

19

pulmonary arteriovenous malformations vs., 11:7 pulmonary artery aneurysm vs., 11:11 Pulmonary artery sarcoma chronic pulmonary embolism vs., 11:20 primary, acute pulmonary embolism vs., 11:16 Pulmonary atresia, 2:48, 2:49, 2:50, 2:51 associated abnormalities, 2:50 branch pulmonary artery stenosis vs., 11:27, 11:28 clinical issues, 2:50 coarctation of aorta vs., 2:11 D-transposition of great arteries associated with, 2:37 differential diagnosis, 2:49 Ebstein anomaly vs., 2:63 imaging, 2:48, 2:49, 2:51 pathology, 2:49, 2:50 staging, grading, & classification, 2:50 with ventricular septal defect, tetralogy of Fallot vs., 2:71 Pulmonary blood flow decreased coarctation of aorta vs., 2:11 L-transposition of great arteries vs., 2:42 increased, L-transposition of great arteries vs., 2:41 Pulmonary capillary hemangiomatosis, pulmonary venoocclusive disease vs., 11:35 Pulmonary edema, noncardiogenic left heart failure vs., 9:12 right heart failure vs., 9:8 Pulmonary embolism acute. See Pulmonary embolism, acute. chronic. See Pulmonary embolism, chronic. coronary artery stenosis vs., 8:50 coronary thrombosis vs., 8:43 P.xxvii

nonatherosclerotic myocardial infarction vs., 8:87 right ventricular infarction vs., 8:84 Pulmonary embolism, acute, 11:14, 11:15, 11:16, 11:17 clinical issues, 11:16 differential diagnosis, 11:16 imaging, 11:14, 11:15, 11:16, 11:17 infarction, left anterior descending distribution vs., 8:76 pathology, 11:16 Pulmonary embolism, chronic, 11:18, 11:19, 11:20, 11:21 associated abnormalities, 11:20 branch pulmonary artery stenosis vs., 11:27 clinical issues, 11:20 differential diagnosis, 11:20 imaging, 11:18, 11:19, 11:20, 11:21 pathology, 11:20

Diagnostic Imaging Cardiovascular Pulmonary hypertension. See Pulmonary arterial hypertension; Pulmonary venous hypertension/pulmonary edema (cardiogenic). Pulmonary hypoplasia, isolated right, Scimitar syndrome vs., 3:27 Pulmonary insufficiency. See Pulmonary valve regurgitation. Pulmonary nodule, solitary, pulmonary arteriovenous malformations vs., 11:7 Pulmonary sequestration, 11:22, 11:23, 11:24, 11:25 associated abnormalities, 11:24 clinical issues, 11:24 differential diagnosis, 11:23, 11:24 extralobar, partial anomalous pulmonary venous return associated with, 3:35 imaging, 11:22, 11:23, 11:25 intralobar, Scimitar syndrome vs., 3:27 pathology, 11:24 pulmonary sling associated with, 2:32 Pulmonary sling, 2:30, 2:31, 2:32, 2:33, 2:34, 2:35 associated abnormalities, 2:32 clinical issues, 2:32 differential diagnosis, 2:31, 2:32 genetics, 2:32 imaging, 2:30, 2:31, 2:33, 2:34, 2:35 left, double aortic arch vs., 2:17 pathology, 2:32 staging, grading, & classification, 2:32 Pulmonary stenosis. See Pulmonary valve stenosis; Pulmonary vein stenosis. Pulmonary trunk, idiopathic dilation pulmonary arterial hypertension vs., 11:31, 11:32 pulmonary valve stenosis vs., 4:41 Pulmonary valve abnormalities, primary, pulmonary valve regurgitation vs., 4:45 atresia. See Pulmonary atresia. surgical complication, pulmonary valve regurgitation vs., 4:45 Pulmonary valve disease, other causes, carcinoid syndrome vs., 4:70 Pulmonary valve regurgitation, 4:44, 4:45, 4:46, 4:47 associated abnormalities, 4:46 clinical issues, 4:46 differential diagnosis, 4:45 genetics, 4:46 imaging, 4:44, 4:45, 4:47 pathology, 4:45, 4:46 staging, grading, & classification, 4:46 Pulmonary valve stenosis, 4:40, 4:41, 4:42, 4:43 associated abnormalities, 4:42 branch pulmonary artery stenosis vs., 11:28 clinical issues, 4:42 congenital, pulmonary arterial hypertension vs., 11:31

D-transposition of great arteries associated with, 2:37 differential diagnosis, 4:41 genetics, 4:42 imaging, 4:40, 4:41, 4:43 pathology, 4:42 right heart failure vs., 9:8 staging, grading, & classification, 4:42 Pulmonary vasculature, 11:2, 11:3, 11:4, 11:5, 11:6, 11:7, 11:8, 11:9, 11:10, 11:11, 11:12, 11:13, 11:14, 11:15, 11:16, 11:17, 11:18, 11:19, 11:20, 11:21, 11:22, 11:23, 11:24, 11:25, 11:26, 11:27, 11:28, 11:29, 11:30, 11:31, 11:32, 11:33, 11:34, 11:35 acute pulmonary embolism, 11:14, 11:15, 11:16, 11:17 differential diagnosis, 11:16 infarction, left anterior descending distribution vs., 8:76 approach to, 11:2, 11:3, 11:4, 11:5 abnormalities in vascular diameter, 11:2, 11:3 imaging anatomy, 11:2 imaging protocols, 11:2 intravascular filling defects, 11:3 radiographic findings, 11:3 branch pulmonary artery stenosis, 11:26, 11:27, 11:28, 11:29 chronic pulmonary embolism, 11:18, 11:19, 11:20, 11:21 branch pulmonary artery stenosis vs., 11:27 differential diagnosis, 11:20 images, 11:4, 11:5 pulmonary arterial hypertension. See Pulmonary arterial hypertension. pulmonary arteriovenous malformation. See Pulmonary arteriovenous malformation. pulmonary artery aneurysm, 11:10, 11:11, 11:12, 11:13 differential diagnosis, 11:11 pulmonary artery pseudoaneurysm vs., 11:9 pulmonary artery pseudoaneurysm. See Pulmonary artery pseudoaneurysm. pulmonary sequestration. See Pulmonary sequestration. pulmonary venoocclusive disease, 11:34, 11:35 Pulmonary vein abnormalities, truncus arteriosus associated with, 2:46 Pulmonary vein mapping, 10:4, 10:5, 10:6, 10:7 clinical issues, 10:5 imaging, 10:4, 10:5, 10:6, 10:7 P.xxviii

differential diagnosis, 10:9 imaging, 10:8, 10:9, 10:10, 10:11 pathology, 10:9 Pulmonary vein thrombosis, pulmonary vein stenosis vs., 10:9 Pulmonary vein varix partial anomalous pulmonary venous return vs., 3:35 pulmonary vein stenosis vs., 10:9 Pulmonary venoocclusive disease, 11:34, 11:35 Pulmonary venous hypertension/pulmonary edema (cardiogenic), 9:26, 9:27, 9:28, 9:29, 9:30, 9:31 clinical issues, 9:28 differential diagnosis, 9:28 imaging, 9:26, 9:27, 9:28, 9:29, 9:30, 9:31 pathology, 9:28 Pulmonary venous return, partial anomalous, 3:34, 3:35 associated abnormalities, 3:35 atrial septal defects associated with, 3:12 differential diagnosis, 3:35 imaging, 3:34, 3:35 other forms, Scimitar syndrome vs., 3:27 patent ductus arteriosus vs., 3:5 persistent left superior vena cava vs., 13:23 pulmonary sling associated with, 2:32 right heart failure vs., 9:8 Pulmonary venous return, total anomalous, 3:30, 3:31, 3:32, 3:33 clinical issues, 3:32 cor triatrium vs., 2:69 D-transposition of great arteries vs., 2:38 differential diagnosis, 3:31 genetics, 3:31 imaging, 3:30, 3:31, 3:33 pathology, 3:31, 3:32 staging, grading, & classification, 3:32 supracardiac type, persistent left superior vena cava vs., 13:23 Pulmonic valve, anatomy, 1:15 tricuspid and pulmonic valves, 1:49 Pulseless disease. See Takayasu arteritis. PVH. See Pulmonary venous hypertension/pulmonary edema (cardiogenic). Pyelonephritis, renal vein thrombosis vs., 15:30 Pyopericardium. See Pericarditis, infectious.

Pulmonary vein stenosis, 10:8, 10:9, 10:10, 10:11 branch pulmonary artery stenosis vs., 11:28 clinical issues, 10:9

Radiation effects May-Thurner syndrome vs., 13:31 neoplastic pericarditis vs., 5:24 valvulitis, aortic stenosis vs., 4:10

20

R

Diagnostic Imaging Cardiovascular Reflux esophagitis, left anterior descending distribution infarction vs., 8:76 Remote infarction. See Myocardial infarction, chronic. Renal arteriovenous fistula, 15:24, 15:25, 15:26, 15:27 clinical issues, 15:26 differential diagnosis, 15:25, 15:26 imaging, 15:24, 15:25, 15:27 nutcracker syndrome vs., 13:35 pathology, 15:26 Renal arteriovenous malformation, renal arteriovenous fistula vs., 15:25 Renal artery aneurysm, renal arteriovenous fistula vs., 15:25 Renal artery atherosclerosis, 15:12, 15:13, 15:14, 15:15 clinical issues, 15:14 differential diagnosis, 15:13, 15:14 imaging, 15:12, 15:13, 15:15 pathology, 15:14 staging, grading, & classification, 15:14 Renal artery stenosis. See Renal artery atherosclerosis. Renal disease, end-stage mitral valve annular calcification associated with, 4:37 mitral valve annular calcification vs., 4:37 Renal failure, infectious pericarditis vs., 5:17 Renal fibromuscular dysplasia, 15:16, 15:17, 15:18, 15:19 clinical issues, 15:18 differential diagnosis, 15:17, 15:18 genetics, 15:18 imaging, 15:16, 15:17, 15:19 pathology, 15:18 polyarteritis nodosa vs., 15:21 renal artery atherosclerosis vs., 15:14 Renal neoplasm, renal arteriovenous fistula vs., 15:25 Renal or ureteral calculus, obstructing, nutcracker syndrome vs., 13:35 Renal tumor, vascular, nutcracker syndrome vs., 13:35 Renal vasculature, anatomy, 15:8, 15:9, 15:10, 15:11 branches of renal arteries, 15:8 intrarenal arterial anatomy, 15:8 normal renal arterial anatomy, 15:10 normal renal arterial and venous anatomy, 15:9 normal renal venous anatomy, 15:11 renal arteries, 15:8 renal veins, 15:8 variant renal arterial anatomy, 15:8 variant renal venous anatomy, 15:8 Renal vasculature, approach to, 15:2, 15:3, 15:4, 15:5, 15:6, 15:7 abnormalities of renal arteries, 15:2, 15:3 aneurysm and pseudoaneurysms, 15:2 arteriovenous communications, 15:2 atherosclerosis, 15:2

fibromuscular dysplasia, 15:2 segmental arterial mediolysis, 15:2 stenosis, 15:2, 15:3 P.xxix

thrombosis/acute arterial occlusion, 15:3 trauma, 15:3 vasculitis, 15:3 abnormalities of renal veins, 15:3, 15:4 anatomic variants, 15:3 arteriovenous communications, 15:3 thrombosis, 15:3 trauma, 15:3 tumor thrombus, 15:3 varices, 15:3, 15:4 anatomic considerations, 15:2 renal arteries, 15:2 renal veins, 15:2 images, 15:5, 15:6, 15:7 imaging, 15:4 Renal vasculature conditions, 15:2, 15:3, 15:4, 15:5, 15:6, 15:7, 15:8, 15:9, 15:10, 15:11, 15:12, 15:13, 15:14, 15:15, 15:16, 15:17, 15:18, 15:19, 15:20, 15:21, 15:22, 15:23, 15:24, 15:25, 15:26, 15:27, 15:28, 15:29, 15:30, 15:31 approach to. See Renal vasculature, approach to. fibromuscular dysplasia, 15:16, 15:17, 15:18, 15:19 differential diagnosis, 15:17, 15:18 polyarteritis nodosa vs., 15:21 renal artery atherosclerosis vs., 15:14 polyarteritis nodosa, 15:20, 15:21, 15:22, 15:23 differential diagnosis, 15:21 renal artery atherosclerosis vs., 15:13 renal arteriovenous fistula, 15:24, 15:25, 15:26, 15:27 differential diagnosis, 15:25, 15:26 nutcracker syndrome vs., 13:35 renal artery atherosclerosis, 15:12, 15:13, 15:14, 15:15 renal vein thrombosis, 15:28, 15:29, 15:30, 15:31 differential diagnosis, 15:29, 15:30 nutcracker syndrome vs., 13:35 Renal vein left retroaortic (vascular variant), nutcracker syndrome vs., 13:35 occlusion. See Renal vein thrombosis. tumor extension, renal vein thrombosis vs., 15:29 Renal vein thrombosis, 15:28, 15:29, 15:30, 15:31 associated abnormalities, 15:30 clinical issues, 15:30 differential diagnosis, 15:29, 15:30 genetics, 15:30 imaging, 15:28, 15:29, 15:31 nutcracker syndrome vs., 13:35 pathology, 15:30

21

Restenosis, in-stent, 8:114, 8:115, 8:116, 8:117, 8:118, 8:119 clinical issues, 8:116 differential diagnosis, 8:115 imaging, 8:114, 8:115, 8:117, 8:118, 8:119 pathology, 8:115, 8:116 staging, grading, & classification, 8:116 Restenosis, post angioplasty, 8:112, 8:113 Restrictive cardiomyopathy. See Cardiomyopathy, restrictive. Retroaortic left renal vein (vascular variant), nutcracker syndrome vs., 13:35 Retroperitoneal fibrosis, aortic graft complications vs., 12:87 Retroperitoneal infection, mycotic aneurysm associated with, 12:34 Retroperitoneal lymphadenopathy, inferior vena cava anomalies vs., 13:15 Retroperitoneal process, renal vein thrombosis vs., 15:30 Rhabdomyoma cardiac sarcoma vs., 6:31 fibroma vs., 6:47 hemangioma vs., 6:41 lipomatous hypertrophy of interatrial septum vs., 6:52 lymphoma vs., 6:58 Rhabdomyosarcoma fibroma vs., 6:47 mitral stenosis vs., 4:25 Rheumatic heart disease, 4:78, 4:79, 4:80, 4:81 aortic regurgitation vs., 4:17 aortic stenosis vs., 4:9 carcinoid syndrome vs., 4:70 clinical issues, 4:80 differential diagnosis, 4:79 imaging, 4:78, 4:79, 4:81 infective endocarditis vs., 4:55 mitral stenosis vs., 4:25 mitral valve prolapse vs., 4:30 mitral valve regurgitation vs., 4:33 multivalvular disease vs., 4:73 pathology, 4:80 pulmonary valve regurgitation vs., 4:45 tricuspid valve regurgitation associated with, 4:52 tricuspid valve stenosis associated with, 4:49 tricuspid valve stenosis vs., 4:49 Rheumatoid arthritis, branch pulmonary artery stenosis vs., 11:27 Rheumatoid nodules, aortic valve, papillary fibroelastoma vs., 6:45 Rib notching, inferior, coarctation of aorta vs., 2:11 Right aortic arch, 2:22, 2:23, 2:24, 2:25, 2:26, 2:27 associated abnormalities, 2:23 clinical issues, 2:23 differential diagnosis, 2:23 imaging, 2:22, 2:23, 2:24, 2:25, 2:26, 2:27

Diagnostic Imaging Cardiovascular pathology, 2:23 pulmonary atresia associated with, 2:50 truncus arteriosus associated with, 2:46 with aberrant left subclavian artery and Kommerell diverticulum, double aortic arch vs., 2:17 with aortic diverticulum, pulmonary sling vs., 2:31 with mirror-image branching and aortic diverticulum, double aortic arch vs., 2:17 Right atrium, anatomy anterior heart surface and right atrium, 1:22 P.xxx

CT, 1:34 morphologic, imaging clues for identifying, 1:16 structure and function, 1:15 Right atrium tumor, carcinoid syndrome vs., 4:70 Right bridging bronchus, pulmonary sling associated with, 2:32 Right common carotid artery steal, subclavian steal syndrome vs., 14:33 Right coronary artery stenosis, ischemic, 8:54, 8:55, 8:56, 8:57 Right heart failure, 9:6, 9:7, 9:8, 9:9 clinical issues, 9:8 cor pulmonale vs., 9:33 differential diagnosis, 9:8 imaging, 9:6, 9:7, 9:8 pathology, 9:8 staging, grading, & classification, 9:8 Right pulmonary artery absence, Scimitar syndrome associated with, 3:27 Right pulmonary hypoplasia, isolated, Scimitar syndrome vs., 3:27 Right-sided obstructive cyanotic heart lesions, with decreased pulmonary vascularity, Ebstein anomaly vs., 2:63 Right tracheal bronchus, pulmonary sling associated with, 2:32 Right ventricle arrhythomogenic dysplasia. See Arrhythmogenic right ventricular dysplasia/cardiomyopathy. dilatation, in endurance athletes, arrhythmogenic right ventricular dysplasia/ cardiomyopathy vs., 7:31, 7:32 hypoplasia, D-transposition of great arteries associated with, 2:37 outflow tachycardia, idiopathic, arrhythmogenic right ventricular dysplasia/cardiomyopathy vs., 7:32 outflow tract obstruction, left ventricular noncompaction associated with, 7:51

volume overload, arrhythmogenic right ventricular dysplasia/cardiomyopathy vs., 7:31 Right ventricle, anatomy graphic, 1:23 morphologic, imaging clues for identifying, 1:16 structure and function, 1:15 Right ventricular hypertrophy, 9:24, 9:25 Right ventricular infarction, 8:82, 8:83, 8:84, 8:85 arrhythmogenic right ventricular dysplasia/cardiomyopathy vs., 7:31 clinical issues, 8:84 differential diagnosis, 8:84 imaging, 8:82, 8:83, 8:84, 8:85 pathology, 8:84 Rubella syndrome, congenital, pulmonary valve stenosis associated with, 4:42 Ryanodine receptor defect, cardiac, arrhythmogenic right ventricular dysplasia/cardiomyopathy associated with, 7:32

S Sarcoidosis, cardiac, 7:42, 7:43, 7:44, 7:45 arrhythmogenic right ventricular dysplasia/cardiomyopathy vs., 7:31 cardiac amyloidosis vs., 7:47 clinical issues, 7:44 differential diagnosis, 7:43, 7:44 imaging, 7:3, 7:42, 7:43, 7:45 pathology, 7:44 post-infarction left ventricular aneurysm vs., 8:98 right ventricular hypertrophy vs., 9:25 right ventricular infarction vs., 8:84 Sarcoma cardiac. See Sarcoma, cardiac. leiomyosarcoma, tumor extension into atria vs., 6:14 liposarcoma cardiac lipoma vs., 6:21, 6:22 lipomatous hypertrophy of interatrial septum vs., 6:51 pulmonary artery acute pulmonary embolism vs., 11:16 chronic pulmonary embolism vs., 11:20 primary, acute pulmonary embolism vs., 11:16 rhabdomyosarcoma fibroma vs., 6:47 mitral stenosis vs., 4:25 soft tissue, persistent sciatic artery vs., 16:41 Sarcoma, cardiac, 6:30, 6:31, 6:32, 6:33, 6:34, 6:35 clinical issues, 6:32 differential diagnosis, 6:31, 6:32 hemangioma vs., 6:41 imaging, 6:30, 6:31, 6:33, 6:34, 6:35 lymphoma vs., 6:58

22

pathology, 6:32 staging, grading, & classification, 6:32 tumor extension into atria vs., 6:14 Schwannoma, carotid space, carotid dissection vs., 14:21 Sciatic artery, persistent, 16:40, 16:41 Scimitar syndrome, 3:26, 3:27, 3:28, 3:29 associated abnormalities, 3:27 clinical issues, 3:28 differential diagnosis, 3:27 genetics, 3:27 imaging, 3:26, 3:27, 3:29 partial anomalous pulmonary venous return associated with, 3:35 pathology, 3:27, 3:28 proximal interruption of pulmonary artery vs., 2:85 pulmonary sling associated with, 2:32 Scleroderma, branch pulmonary artery stenosis vs., 11:27 Segmental arterial mediolyis, renal fibromuscular dysplasia vs., 15:18 P.xxxi

Semilunar valves, MR of semilunar valves, 1:48 Senning procedure, 2:4 Septal aneurysm, membranous, associated with ventricular septal defect, 6:37 Septal defects. See Atrial septal defects; Ventricular septal defects. Septal hypertrophy, mitral valve regurgitation associated with, 4:33 Septic emboli, pulmonary arteriovenous malformations vs., 11:7 Septum, interatrial, lipomatous hypertrophy of. See Lipomatous hypertrophy, interatrial septum. Shunts, 3:2, 3:3, 3:4, 3:5, 3:6, 3:7, 3:8, 3:9, 3:10, 3:11, 3:12, 3:13, 3:14, 3:15, 3:16, 3:17, 3:18, 3:19, 3:20, 3:21, 3:22, 3:23, 3:24, 3:25, 3:26, 3:27, 3:28, 3:29, 3:30, 3:31, 3:32, 3:33, 3:34, 3:35 approach to, 3:2, 3:3 clinical implications, 3:3 embryology, 3:3 imaging protocols, 3:3 types of intracardiac shunts, 3:2, 3:3 atrial septal defects. See Atrial septal defects. endocardial cushion defect, 3:22, 3:23, 3:24, 3:25 differential diagnosis, 3:23 patent ductus arteriosus vs., 3:5 left-to-right, pseudocoarctation associated with, 12:66 partial anomalous pulmonary venous return. See Pulmonary venous return, partial anomalous. patent ductus arteriosus. See Patent ductus arteriosus. Scimitar syndrome. See Scimitar syndrome.

Diagnostic Imaging Cardiovascular total anomalous pulmonary venous return. See Pulmonary venous return, total anomalous. ventricular septal defects. See Ventricular septal defects. Sinoatrial node branch, anomalous left circumflex coronary artery vs., 8:23 Sinus of Valsalva aneurysm bicuspid aortic valve associated with, 4:22 characteristics, 6:37 pseudocoarctation associated with, 12:66 Sinus of Valsalva rupture, aortic regurgitation vs., 4:17 Sinus venosus atrial septal defect partial anomalous pulmonary venous return associated with, 3:35 Scimitar syndrome associated with, 3:27 Situs ambiguous. See Heterotaxia syndromes. Situs inversus abdominal, heterotaxia syndromes vs., 2:57 atrial, L-transposition of great arteries associated with, 2:42 Situs inversus totalis, heterotaxia syndromes vs., 2:57 Situs solitus abdominal, with true dextrocardia, Scimitar syndrome vs., 3:27 and levocardia, abdominal, heterotaxia syndromes vs., 2:57 Soft tissue sarcoma, persistent sciatic artery vs., 16:41 Solitary pulmonary nodule, pulmonary arteriovenous malformations vs., 11:7 Spinal cord stimulator, pacemakers/implantable cardioverterdefibrillators vs., 10:14 Spinal infection, mycotic aneurysm associated with, 12:34 Splenectomy, chronic pulmonary embolism associated with, 11:20 Splenorenal shunt, spontaneous, nutcracker syndrome vs., 13:35 Standing waves, renal fibromuscular dysplasia vs., 15:18 Stent, coronary artery coronary artery calcification vs., 8:33 imaging, 1:3 in-stent restenosis, 8:114, 8:115, 8:116, 8:117, 8:118, 8:119 Stent thrombosis acute, in-stent restenosis vs., 8:115 post-angioplasty restenosis vs., 8:113 Stents post endovascular, aortic graft complications vs., 12:87 post-stent aneurysm, in-stent restenosis vs., 8:115 Stimulators, pacemakers/implantable cardioverter-defibrillators vs., 10:14 Stress cardiomyopathy. See Takotsubo cardiomyopathy.

Stroke. See Ischemic stroke, acute. Subaortic stenosis, idiopathic hypertrophic. See Cardiomyopathy, hypertrophic. Subarachnoid hemorrhage vasospasm, vertebral artery dissection vs., 14:29 Subclavian artery, aberrant pseudocoarctation associated with, 12:66 truncus arteriosus associated with, 2:46 Subclavian artery dissection, subclavian artery stenosis/occlusion vs., 16:10 Subclavian artery stenosis/occlusion, 16:8, 16:9, 16:10, 16:11 associated abnormalities, 16:10 associated syndromes, 16:9 clinical issues, 16:10 differential diagnosis, 16:9, 16:10 imaging, 16:8, 16:9, 16:11 pathology, 16:10 proximal to left internal mammary artery origin, post-coronary artery bypass graft atherosclerosis vs., 8:125 Subclavian steal syndrome, 14:32, 14:33, 14:34, 14:35 clinical issues, 14:34 differential diagnosis, 14:33, 14:34 imaging, 14:32, 14:33, 14:35 pathology, 14:34 staging, grading, & classification, 14:34 subclavian artery stenosis/occlusion associated with, 16:9 P.xxxii

Subclavian vein thrombosis, 16:12, 16:13, 16:14, 16:15 associated abnormalities, 16:14 clinical issues, 16:14 differential diagnosis, 16:14 imaging, 16:12, 16:13, 16:14, 16:15 pathology, 16:14 Subendocardial fibroelastosis, left ventricular noncompaction associated with, 7:52 Submitral ring or web, cor triatrium vs., 2:69 Subvalvular aortic stenosis, aortic stenosis vs., 4:9 Superficial thrombophlebitis, deep vein thrombosis of lower extremity vs., 16:48 Superior vena cava anomalous, Scimitar syndrome associated with, 3:27 left, truncus arteriosus associated with, 2:46 normal anatomy, 13:6 persistent, ± coronary sinus ASD, pulmonary sling associated with, 2:32 variant anatomy, 13:3 Superior vena cava syndrome, 13:10, 13:11, 13:12, 13:13 clinical issues, 13:12 differential diagnosis, 13:11, 13:12

23

imaging, 13:10, 13:11, 13:13 pathology, 13:12 Supravalvular aortic stenosis aortic stenosis vs., 4:10 bicuspid aortic valve associated with, 4:22 Supraventricular tachycardia, paroxysmal, hypoplastic left heart syndrome vs., 2:53 Surgery, May-Thurner syndrome vs., 13:31 Swyer-James-McLeod syndrome, proximal interruption of pulmonary artery vs., 2:85 Syndrome X, coronary artery stenosis vs., 8:50 Systemic lupus erythematosus branch pulmonary artery stenosis vs., 11:27 polyarteritis nodosa vs., 15:21 rheumatic heart disease vs., 4:79

T Tachycardia idiopathic right ventricular outflow tachycardia, arrhythmogenic right ventricular dysplasia/cardiomyopathy vs., 7:32 paroxysmal supraventricular, hypoplastic left heart syndrome vs., 2:53 Takayasu arteritis, 12:54, 12:55 aortic intramural hematoma vs., 12:41 branch pulmonary artery stenosis vs., 11:27 chronic pulmonary embolism vs., 11:20 coarctation of aorta vs., 2:11 coronary fistula vs., 8:132 coronary thrombosis vs., 8:43 differential diagnosis, 12:55 giant cell arteritis vs., 12:57 imaging, 12:54, 12:55 penetrating aortic atherosclerotic ulcer vs., 12:45 renal artery atherosclerosis vs., 15:13 Takotsubo cardiomyopathy, 7:62, 7:63, 7:64, 7:65 acute myocardial infarction vs., 8:68 Chagas disease vs., 7:55, 7:56 clinical issues, 7:64 differential diagnosis, 7:63 imaging, 7:62, 7:63, 7:65 infarction, left anterior descending distribution vs., 8:76 nonatherosclerotic myocardial infarction vs., 8:87 pathology, 7:64 post-infarction left ventricular aneurysm vs., 8:98 Technical artifacts, cardiac thrombus vs., 6:26 Technical errors, deep vein thrombosis of lower extremity vs., 16:48 Teratoma

Diagnostic Imaging Cardiovascular cardiac or pericardial, cardiac lipoma vs., 6:21 cardiac sarcoma vs., 6:31, 6:32 hemangioma vs., 6:42 lipomatous hypertrophy of interatrial septum vs., 6:51 Tetralogy of Fallot, 2:70, 2:71, 2:72, 2:73, 2:74, 2:75 clinical issues, 2:72 coarctation of aorta vs., 2:11 differential diagnosis, 2:71 Ebstein anomaly vs., 2:63 genetics, 2:71, 2:72 imaging, 2:70, 2:71, 2:73, 2:74, 2:75 pathology, 2:71, 2:72 proximal interruption of pulmonary artery associated with, 2:85 pulmonary sling associated with, 2:32 pulmonary valve stenosis associated with, 4:42 Scimitar syndrome associated with, 3:27 staging, grading, & classification, 2:72 ventricular septal defects associated with, 3:18 with pulmonary atresia, pulmonary atresia vs., 2:49 Tetralogy of Fallot: BT shunt, 2:76, 2:77 differential diagnosis, 2:77 imaging, 2:76, 2:77 modified Blalock-Taussig shunt, 2:3 Tetralogy of Fallot: definitive repair, 2:78, 2:79, 2:80, 2:81, 2:82, 2:83 clinical issues, 2:80 diagnostic checklist, 2:80 history of, 2:4 imaging, 2:78, 2:79, 2:80, 2:81, 2:82, 2:83 ß-t halassemia, iron overload syndrome associated with, 7:60 Thoracic aorta and great vessels, 12:10, 12:11, 12:12, 12:13, 12:14, 12:15, 12:16, 12:17, 12:18, 12:19, 12:20, 12:21, 12:22, 12:23, 12:24, 12:25, 12:26, 12:27, 12:28, 12:29, 12:30, 12:31, 12:32, 12:33, 12:34, 12:35, 12:36, 12:37, 12:38, 12:39, 12:40, 12:41, 12:42, 12:43, 12:44, 12:45, 12:46, 12:47, 12:48, 12:49, 12:50, 12:51, 12:52, 12:53, 12:54, 12:55, 12:56, 12:57, 12:58, 12:59, 12:60, 12:61, 12:62, 12:63, 12:64, 12:65, 12:66, 12:67, 12:68, 12:69, 12:70, 12:71, 12:72, 12:73, 12:74, 12:75 anatomy. See Thoracic aorta and great vessels, anatomy. aortic aneurysm, 12:26, 12:27, 12:28, 12:29, 12:30, 12:31 aortic dissection. See Aortic dissection. P.xxxiii

aortic intramural hematoma, 12:40, 12:41, 12:42, 12:43 aortic dissection vs., 12:50 differential diagnosis, 12:41

approach to, 12:2, 12:3 See also Aortic syndrome, acute, approach to. acquired pathology, 12:2 congenital pathology, 12:2 images, 12:3 chronic post-traumatic pseudoaneurysm, 12:36, 12:37, 12:38, 12:39 ductus diverticulum, 12:72, 12:73, 12:74, 12:75 differential diagnosis, 12:73, 12:74 traumatic aortic laceration vs., 12:70 giant cell arteritis. See Giant cell arteritis. Marfan syndrome. See Marfan syndrome. mycotic aneurysm, 12:32, 12:33, 12:34, 12:35 abdominal aortic aneurysm with rupture vs., 12:83 differential diagnosis, 12:33 penetrating atherosclerotic ulcer, 12:44, 12:45, 12:46, 12:47 aortic dissection vs., 12:50 approach to, 12:4 differential diagnosis, 12:45 pseudocoarctation, 12:64, 12:65, 12:66, 12:67 Takayasu arteritis. See Takayasu arteritis. traumatic aortic laceration, 12:68, 12:69, 12:70, 12:71 Thoracic aorta and great vessels, anatomy, 12:10, 12:11, 12:12, 12:13, 12:14, 12:15, 12:16, 12:17, 12:18, 12:19 anatomic imaging issues, 12:11 anatomic relationships, 12:11 aortic root CT anatomy, 12:14, 12:15 aortic root short-axis planes, 12:17 imaging anatomy, 12:10, 12:11 standard measurements, 12:16 standard planes of aorta, 12:18 TAVI/R planning, 12:19 thoracic aorta and great vessels graphic, 12:12 normal anatomy, 12:13 Thoracic outlet syndrome subclavian artery stenosis/occlusion associated with, 16:9 subclavian artery stenosis/occlusion vs., 16:9, 16:10 subclavian vein thrombosis vs., 16:14 superior vena cava syndrome vs., 13:11 Thorson-Bioerck syndrome. See Carcinoid syndrome. Thromboembolism, renal artery atherosclerosis vs., 15:14 Thrombophlebitis, superficial, deep vein thrombosis of lower extremity vs., 16:48 Thrombosis acute, acute lower extremity ischemia vs., 16:29 axillary vein, subclavian vein thrombosis associated with, 16:14

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coronary, 8:42, 8:43, 8:44, 8:45, 8:46, 8:47 pseudothrombosis, tumor extension into atria vs., 6:14 pulmonary vein, pulmonary vein stenosis vs., 10:9 subclavian vein, 16:12, 16:13, 16:14, 16:15 valvular prosthesis complications vs., 4:66 Thrombosis, deep venous chronic, May-Thurner syndrome vs., 13:32 deep venous thrombosis, stenosis, or occlusion, upper extremity veins, superior vena cava syndrome vs., 13:12 lower extremity, 16:46, 16:47, 16:48, 16:49 May-Thurner syndrome associated with, 13:32 Thrombosis, post-coronary artery bypass graft, 8:120, 8:121, 8:122, 8:123 differential diagnosis, 8:121 post-coronary artery bypass graft atherosclerosis vs., 8:125 Thrombosis, renal vein, 15:28, 15:29, 15:30, 15:31 differential diagnosis, 15:29, 15:30 nutcracker syndrome vs., 13:35 Thrombosis, stent acute, in-stent restenosis vs., 8:115 post-angioplasty restenosis vs., 8:113 Thrombus, cardiac, 6:24, 6:25, 6:26, 6:27, 6:28, 6:29 apical, hypereosinophilic syndrome vs., 7:38 cardiac lipoma vs., 6:22 cardiac sarcoma vs., 6:31 characteristics, 6:37 clinical issues, 6:26 coronary artery dissection vs., 8:63 differential diagnosis, 6:25, 6:26 imaging, 6:24, 6:25, 6:27, 6:28, 6:29 intracardiac, atrial myxoma vs., 6:17 intraventricular, left ventricular noncompaction associated with, 7:51 left atrial, 10:18, 10:19, 10:20, 10:21 left ventricular, left ventricular noncompaction vs., 7:51 lipomatous hypertrophy of interatrial septum vs., 6:52 lymphoma vs., 6:57, 6:58 metastatic disease vs., 6:10 papillary fibroelastoma vs., 6:45 pathology, 6:26 tumor extension into atria vs., 6:13, 6:14 tumor mimics vs., 6:38 Thrombus/embolus, tumor acute pulmonary embolism vs., 11:16 subclavian vein thrombosis vs., 16:14 Thymic cysts, pericardial cyst vs., 5:32 Thymolipoma, pericardial cyst vs., 5:32 Thyroid replacement therapy, chronic pulmonary embolism associated with, 11:20

Diagnostic Imaging Cardiovascular Total anomalous pulmonary venous return. See Pulmonary venous return, total anomalous. Tracheal bronchus, right, pulmonary sling associated with, 2:32 Tracheal stenosis, pulmonary sling associated with, 2:32 P.xxxiv

Tracheobronchomalacia, double aortic arch associated with, 2:17 Transcatheter aortic valve replacement, 4:12, 4:13, 4:14, 4:15 Transfusional iron overload, iron overload syndrome vs., 7:60 Transient ischemic attack, subclavian artery stenosis/occlusion associated with, 16:10 D-transposition of great arteries, 2:36, 2:37, 2:38, 2:39 associated abnormalities, 2:38 clinical issues, 2:38 differential diagnosis, 2:37, 2:38 imaging, 2:36, 2:37, 2:39 pathology, 2:38 repairs, 2:4 staging, grading, & classification, 2:38 truncus arteriosus vs., 2:45 L-transposition of great arteries, 2:40, 2:41, 2:42, 2:43 associated abnormalities, 2:43 clinical issues, 2:43 D-transposition of great arteries vs., 2:37, 2:38 differential diagnosis, 2:41, 2:42 genetics, 2:43 imaging, 2:40, 2:41, 2:43 pathology, 2:43 repairs, 2:4 truncus arteriosus vs., 2:45 Transvenous cardiac metastasis. See Atria, tumor extension into. Trauma cystic adventitial disease vs., 16:38 infectious pericarditis vs., 5:18 lower extremity aneurysms vs., 16:26 May-Thurner syndrome vs., 13:31 Traumatic aortic laceration, 12:68, 12:69, 12:70, 12:71 Traumatic arterial injury, acute lower extremity ischemia vs., 16:29 Traumatic occlusion femoropopliteal artery occlusive disease vs., 16:34 iliac artery occlusive disease vs., 16:17 Traumatic pseudoaneurysm, coarctation of aorta vs., 2:11 Tricuspid atresia Ebstein anomaly vs., 2:63, 2:64 pulmonary atresia associated with, 2:50 ventricular septal defects associated with, 3:18 with ventricular septal defect pulmonary atresia vs., 2:49

tetralogy of Fallot vs., 2:71 Tricuspid insufficiency. See Tricuspid valve regurgitation. Tricuspid valve anatomy, 1:15 tricuspid and pulmonic valves, 1:49 disease, other causes, carcinoid syndrome vs., 4:70 left-sided dysplasia, L-transposition of great arteries associated with, 2:42 obstruction, tricuspid valve stenosis vs., 4:49 Tricuspid valve regurgitation, 4:50, 4:51, 4:52, 4:53 associated abnormalities, 4:52 clinical issues, 4:52 differential diagnosis, 4:51 primary tricuspid regurgitation, 4:51 secondary tricuspid regurgitation, 4:51 Ebstein anomaly vs., 2:63 imaging, 4:50, 4:51, 4:53 pathology, 4:52 Tricuspid valve stenosis, 4:48, 4:49 congenital, tricuspid valve stenosis vs., 4:49 differential diagnosis, 4:49 imaging, 4:48, 4:49 Trilogy of Fallot, tetralogy of Fallot vs., 2:71 Trisomy 21 atrial septal defects associated with, 3:12 endocardial cushion defect associated with, 3:24 Truncus arteriosus, 2:44, 2:45, 2:46, 2:47 associated abnormalities, 2:46 clinical issues, 2:46 D-transposition of great arteries vs., 2:38 differential diagnosis, 2:45 genetics, 2:46 imaging, 2:44, 2:45, 2:47 pathology, 2:45, 2:46 staging, grading, & classification, 2:46 ventricular septal defects associated with, 3:18 Truncus arteriosus type 4. See Pulmonary atresia. Trypanosomiasis, American. See Chagas disease. Tumor extension into atria, 6:12, 6:13, 6:14, 6:15 Tumor mimics, 6:36, 6:37, 6:38, 6:39 clinical issues, 6:38 differential diagnosis, 6:38 imaging, 6:36, 6:37, 6:38, 6:39 staging, grading, & classification, 6:38 Tumor thrombus/embolus acute pulmonary embolism vs., 11:16 subclavian vein thrombosis vs., 16:14 Tumors. See Neoplastic disease. Turner syndrome, bicuspid aortic valve associated with, 4:22

25

U Uhl anomaly, and arrhythmogenic right ventricular dysplasia, Ebstein anomaly vs., 2:63 Uremic pericarditis, 5:20, 5:21 Ureteral or renal calculus, obstructing, nutcracker syndrome vs., 13:35

V VACTERL, pulmonary sling associated with, 2:32 Vagal nerve stimulator, pacemakers/implantable cardioverterdefibrillators vs., 10:14 Valve replacement, in situ, left ventricular apical aortic conduit vs., 4:83 Valves, anatomy anatomy, 1:15 cardiac skeleton and heart valves, 1:45 CT atrioventricular valve, 1:47 CT and MR of aortic valve, 1:54 left heart valves, 1:53 mitral valve, 1:55 right heart valves, 1:50 echocardiography of aortic and mitral valves, 1:52 left heart valves, 1:51 MR CT and MR of aortic valve, 1:54 semilunar valves, 1:48 valve function, 1:56, 1:57 radiography of prosthetic aortic and mitral valves, 1:46 tricuspid and pulmonic valves, 1:49 Valvular disease, 4:2, 4:3, 4:4, 4:5, 4:6, 4:7, 4:8, 4:9, 4:10, 4:11, 4:12, 4:13, 4:14, 4:15, 4:16, 4:17, 4:18, 4:19, 4:20, 4:21, 4:22, 4:23, 4:24, 4:25, 4:26, 4:27, 4:28, 4:29, 4:30, 4:31, 4:32, 4:33, 4:34, 4:35, 4:36, 4:37, 4:38, 4:39, 4:40, 4:41, 4:42, 4:43, 4:44, 4:45, 4:46, 4:47, 4:48, 4:49, 4:50, 4:51, 4:52, 4:53, 4:54, 4:55, 4:56, 4:57, 4:58, 4:59, 4:60, 4:61, 4:62, 4:63, 4:64, 4:65, 4:66, 4:67, 4:68, 4:69, 4:70, 4:71, 4:72, 4:73, 4:74, 4:75, 4:76, 4:77, 4:78, 4:79, 4:80, 4:81, 4:82, 4:83, 4:84, 4:85 aortic regurgitation, 4:16, 4:17, 4:18, 4:19 differential diagnosis, 4:17, 4:18 dilated nonischemic cardiomyopathy vs., 7:20 aortic stenosis. See Aortic valve stenosis. approach to. See Valvular disease, approach to. bicuspid aortic valve. See Aortic valve, bicuspid. carcinoid syndrome. See Carcinoid syndrome.

Diagnostic Imaging Cardiovascular dilated nonischemic cardiomyopathy vs., 7:20 infective endocarditis. See Endocarditis, infective. left ventricular apical aortic conduit, 4:82, 4:83, 4:84, 4:85 mitral annular calcification. See Mitral valve annular calcification. mitral regurgitation. See Mitral valve regurgitation. mitral stenosis, 4:24, 4:25, 4:26, 4:27 congenital, mitral stenosis vs., 4:25 differential diagnosis, 4:25 mitral valve prolapse, 4:28, 4:29, 4:30, 4:31 coronary artery stenosis vs., 8:50 differential diagnosis, 4:30 multivalvular, 4:72, 4:73, 4:74, 4:75, 4:76, 4:77 calcific, mitral valve annular calcification vs., 4:37 differential diagnosis, 4:73 prosthetic valve complications, 4:64, 4:65, 4:66, 4:67 pulmonary regurgitation, 4:44, 4:45, 4:46, 4:47 pulmonary stenosis. See Pulmonary valve stenosis. rheumatic heart disease. See Rheumatic heart disease. single-valve, primary, multivalvular disease vs., 4:73 suggested protocols by indication, 1:10 transcatheter aortic valve replacement, 4:12, 4:13, 4:14, 4:15 tricuspid regurgitation, 4:50, 4:51, 4:52, 4:53 differential diagnosis, 4:51 Ebstein anomaly vs., 2:63 tricuspid stenosis, 4:48, 4:49 congenital, tricuspid valve stenosis vs., 4:49 differential diagnosis, 4:49 valvular prosthesis. See Valvular prosthesis. Valvular disease, approach to, 4:2, 4:3, 4:4, 4:5, 4:6, 4:7 anatomy and physiology, 4:2 CT role, 4:2, 4:3 images, 4:4, 4:5, 4:6, 4:7 introduction, 4:2 MR role, 4:2 special cases, 4:3 transcatheter aortic valve replacement, 4:3 valvular masses, 4:3 valvular prosthesis, 4:3 Valvular pannus cardiac thrombus vs., 6:26 valvular prosthesis complications vs., 4:66 Valvular prosthesis, 4:58, 4:59, 4:60, 4:61, 4:62, 4:63 clinical issues, 4:60 differential diagnosis, 4:60

dysfunction, infective endocarditis vs., 4:55 imaging, 4:58, 4:59, 4:61, 4:62, 4:63 radiography of prosthetic aortic and mitral valves, 1:46 Valvular prosthesis complications, 4:64, 4:65, 4:66, 4:67 clinical issues, 4:66 differential diagnosis, 4:66 imaging, 4:64, 4:65, 4:66, 4:67 pathology, 4:66 Valvular vegetation cardiac thrombus vs., 6:25 papillary fibroelastoma vs., 6:45 Van Praagh segmental approach to congenital heart disease, 2:2, 2:3 Varices/collaterals, inferior vena cava anomalies vs., 13:15 Varicoceles, male, nutcracker syndrome associated with, 13:35 Vascular neoplasms, lower extremity arteriovenous fistula vs., 16:43 Vasculitis acute lower extremity ischemia vs., 16:29 coronary thrombosis vs., 8:43 femoropopliteal artery occlusive disease vs., 16:34 iliac artery occlusive disease vs., 16:18 renal artery atherosclerosis vs., 15:13 renal fibromuscular dysplasia vs., 14:17 subclavian artery stenosis/occlusion vs., 16:10 Vasospasm. See also Coronary spasm. extracranial atherosclerosis vs., 14:14 subarachnoid hemorrhage vasospasm, vertebral artery dissection vs., 14:29 Velocardiofacial (Shprintzen) syndrome, truncus arteriosus associated with, 2:46 Vena cava. See Inferior vena cava entries; Superior vena cava. Venography, CT cardiac. See Cardiac vein mapping. Venoocclusive diseases, pathologybased imaging issues, 13:8 Venous anatomy, 13:2, 13:3, 13:4, 13:5, 13:6, 13:7 abdominal and pelvic venous anatomy, 13:3 portal venous system, 13:3 systemic, 13:3 cervicothoracic venous anatomy, 13:2 lower extremity venous anatomy, 13:2, 13:3 deep veins, 13:2, 13:3 perforator veins, 13:3 superficial veins, 13:2 neck, thoracic inlet, and upper thorax, 13:5 normal abdominal systemic and portal venous anatomy, 13:4 thoracic veins, superior venal cava and tributaries, 13:6 upper extremity venous anatomy, 13:2 deep veins, 13:2

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superficial veins, 13:2 variant venous anatomy, 13:3 inferior vena cava and tributaries, 13:3 superior vena cava and tributaries, 13:3 Venous aneurysms, pathology-based imaging issues, 13:9 Venous collaterals, coarctation of aorta vs., 2:11 Venous compression, extrinsic, subclavian vein thrombosis vs., 16:14 Venous conditions, 13:2, 13:3, 13:4, 13:5, 13:6, 13:7, 13:8, 13:9, 13:10, 13:11, 13:12, 13:13, 13:14, 13:15, 13:16, 13:17, 13:18, 13:19, 13:20, 13:21, 13:22, 13:23, 13:24, 13:25, 13:26, 13:27, 13:28, 13:29, 13:30, 13:31, 13:32, 13:33, 13:34, 13:35, 13:36, 13:37 approach to, 13:8, 13:9 anatomy-based imaging issues, 13:8, 13:9 imaging protocols, 13:9 pathology-based imaging issues, 13:8, 13:9 azygos continuation of inferior vena cava, 13:26, 13:27, 13:28, 13:29 differential diagnosis, 13:27, 13:28 Scimitar syndrome associated with, 3:27 inferior vena cava anomalies. See Inferior vena cava anomalies. inferior vena cava occlusion, 13:18, 13:19, 13:20, 13:21 differential diagnosis, 13:19, 13:20 intrahepatic, due to tumor or thrombosis, azygos continuation of inferior vena cava vs., 13:28 left superior vena cava. See Left superior vena cava, persistent. May-Thurner syndrome, 13:30, 13:31, 13:32, 13:33 differential diagnosis, 13:31, 13:32 inferior vena cava occlusion associated with, 13:20 nutcracker syndrome. See Nutcracker syndrome. superior vena cava syndrome, 13:10, 13:11, 13:12, 13:13 Venous insufficiency, pathology-based imaging issues, 13:8, 13:9 Venous malformations. See also Arteriovenous malformations. congenital, nutcracker syndrome vs., 13:35 lower extremity arteriovenous fistula vs., 16:43 Ventricles. See Left ventricle; Right ventricle. Ventricular assist devices, 9:18, 9:19, 9:20, 9:21 anatomy-based imaging issues, 9:19 clinical implications, 9:19, 9:20 equipment, 9:20 imaging, 9:18, 9:21 imaging anatomy, 9:19

Diagnostic Imaging Cardiovascular left ventricular apical aortic conduit vs., 4:83 pathology-based imaging issues, 9:19 post-procedure outcomes, 9:20 Ventricular myocardium, isolated noncompaction of. See Left ventricular noncompaction. Ventricular septal defects, 3:16, 3:17, 3:18, 3:19, 3:20, 3:21 associated abnormalities, 3:17, 3:18 atrial septal defects vs., 3:11 bicuspid aortic valve associated with, 4:22 clinical issues, 3:18 coarctation of aorta associated with, 2:12 congenital, ventricular septal rupture vs., 8:111 D-transposition of great arteries associated with, 2:37 differential diagnosis, 3:17 endocardial cushion defect vs., 3:23 imaging, 3:16, 3:17, 3:19, 3:20, 3:21 in pulmonary atresia, tetralogy of Fallot vs., 2:71 in tricuspid atresia pulmonary atresia vs., 2:49

tetralogy of Fallot vs., 2:71 L-transposition of great arteries associated with, 2:42 patent ductus arteriosus vs., 3:5 pathology, 3:17, 3:18 pseudocoarctation associated with, 12:66 pulmonary sling associated with, 2:32 pulmonary valve stenosis associated with, 4:42 repair of, 2:4 Scimitar syndrome associated with, 3:27 staging, grading, & classification, 3:18 truncus arteriosus associated with, 2:46 Ventricular septal rupture, 8:110, 8:111 differential diagnosis, 8:111 papillary muscle rupture vs., 8:80 Vertebral arteriovenous fistula, subclavian steal syndrome vs., 14:33 Vertebral artery hypoplasia, subclavian steal syndrome vs., 14:34 occlusion/severe stenosis, subclavian steal syndrome vs., 14:33

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Vertebral artery dissection, 14:28, 14:29, 14:30, 14:31 clinical issues, 14:30 differential diagnosis, 14:29 genetics, 14:30 imaging, 14:28, 14:29, 14:31 pathology, 14:30 Viral myocarditis, Chagas disease vs., 7:55 Volume overload right ventricular, arrhythmogenic right ventricular dysplasia/cardiomyopathy vs., 7:31 uremic pericarditis vs., 5:21

W Waterston-Cooley shunt, BlalockTaussig shunt for tetralogy of Fallot vs., 2:77 Wegener granulomatosis branch pulmonary artery stenosis vs., 11:27 polyarteritis nodosa vs., 15:21 Williams syndrome, pulmonary valve stenosis associated with, 4:42