Radiological Procedures (A Guideline) [3 ed.] 8178555654, 9788178555652

Table of contents :
Radiological Procedures (A GUIDELINE)
Preface to Third Edition
Contents
Chapter 1 - Contrast Media
Chapter 2 - Intravenous Urogram-1.V.U.
Chapter 3 - Micturating Cystourethrogram (MCU)
Chapter 4 - Retrograde Pyeloureterography
Chapter 5 - Contrast Media in GIT
Chapter 6 - Barium Swallow
Chapter 7 - Barium Meal
Chapter 8 - Barium Meal Follow Through
Chapter 9 - Enteroclysis (Small Bowel Enema)
Chapter 10 - Barium Enema
Chapter 11 - Hysterosalpingography
Chapter 12 - Fallopian Tube Recanalisation
Chapter 13 - Sialography
Chapter 14 - T-Tube Cholangiography
Chapter 15 - Percutaneous Transhepatic Cholangiography
Chapter 16 - Catheters
Chapter 17 - Angiography
Chapter 18 - Phlebography
Chapter 19 - Dacrocystography
Chapter 20 - lnterventional Radiology
Chapter 21 - New trends in Radiography
Chapter 22 - Mammography and Sono-Elastography
Chapter 23 - Doppler in Obstetrics and Peripheral Vessels
Chapter 24 - Advances in Interventions
Chapter 25 - CT Procedures
Chapter 26 - MR Procedures
Chapter 27 - Positron Emission Tomography (PET)

Citation preview

Dr. Bhushan N Lakhkar

·

A GUIDELINE

Radiological Procedures {A Guideline)

Dr Bhushan N. Lakhkar Professor and Head Department of Radiodiagnosis & Imaging Shri BMPatil Medical College, BLDE University, Bijapur, Kamataka

Assisted by

Dr Bhushita Lakhkar Guru Asst. Professor, and Department of Radiodiagnosis & Imaging Shri BMPatil Medical College, BLDE University, Bijapur, Kamataka

ARYA PUBLICATIONS (AVICHAL PUBLISHING COMPANY)

INDUSTRIAL AREA, TRILOKPUR ROAD, KALA AMB 173 030, DISTT. SIRMOUR (HP) Delhi Office: 1002 Faiz Road (opp. Hanuman Murti), Karol Bagh, New Delhi 110 005

The book has been published in good faith that the views and opinions expressed in this book are solely those of the original contri.butor(s)/ author. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means [graphic, electronic or mechanical, including photocopying, recording, taping or information retrieval system] without the written permission of the copyright holder, application for which should be addressed to the publisher. Such written permission must also be obtained before any part of this publication is stored in a retrieval system of any nature. Breach of this condition is liable for legal action. Exhaustive efforts have been made to ensure accuracy and correctness of contents of the book at the time of going to press. However, in view of possibility of human error or changes in medical science, neither the author, publisher nor any other person who has been involved in preparation of this work accepts any responsibility for any errors or omissions or results obtained from use of information given in the book. The publisher shall not be liable for any direct, consequential, or incidental damages arising out of the use of the book. In case of binding mistake, misprints, or missing pages etc, the publisher's entire liability, and your exclusive remedy, is replacement of the book within one month of purchase by similar edition/reprint of the book. In case of any dispute, all legal matters are to be settled under Delhi Jurisdiction only.

Published by:

ARYA PUBLICATIONS

(Avichal Publishing Company)

7, Industrial Area, Trilokpur Road Kala Amb-173030, Distt. Sirmour (HP)

Delhi Office:

1002 Faiz Road (opp. Hanuman Murti), Karol Bagh, New Delhi-110 005 (India) Phone: 011-28752745, 28752604, 28755383 Fax: 011-28756921 Email: [email protected] Website: www.apcbooks.co.in ISBN-978-81-7855-565-2 © Author First Edition: 2002 Reprint: 2008 Second Edition: 2010 Reprint: 2014 Third Edition: 2016 Reprint: 2017 Price: � �0.00

Laser Typesetting at:

Eltee Printmaster (P)

Printed at:

Deepak Offset Printers

Bawana Ind. Area, Delhi

NOTICE

Information contained in this book is uptodate, believed to be reliable when checked with the sources and is in accordance with the accepted standard, at the time of publication. However, with ongoing research and passage of time, new knowledge may modify some of it. The reader should, therefore, approach the book with a realistic attitude (particularly the drugs and doses) and should carry the professional responsibility. The readers are requested to verify the information contained herein from other sources. Neither the publisher nor the author(s)/editor(s) assumes any liability for any injury and/ or damage to persons or property arising from the use of material in this book.

Radiological Procedures {A Guideline)

Dr Bhushan N. Lakhkar Professor and Head Department of Radiodiagnosis & Imaging Shri BMPatil Medical College, BLDE University, Bijapur, Kamataka

Assisted by

Dr Bhushita Lakhkar Guru Asst. Professor, and Department of Radiodiagnosis & Imaging Shri BMPatil Medical College, BLDE University, Bijapur, Kamataka

ARYA PUBLICATIONS (AVICHAL PUBLISHING COMPANY)

INDUSTRIAL AREA, TRILOKPUR ROAD, KALA AMB 173 030, DISTT. SIRMOUR (HP) Delhi Office: I 002 Faiz Road (opp. Hanuman Murti), Karol Bagh, New Delhi 110 005

The book has been published in good faith that the views and opinions expressed in this book are solely those of the original contributor(s)/author. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means [graphic, electronic or mechanical, including photocopying, recording, taping or information retrieval system) without the written permission of the copyright holder, application for which should be addressed to the publisher. Such written permission must also be obtained before any part of this publication is stored in a retrieval system of any nature. Breach of this condition is liable for legal action. Exhaustive efforts have been made to ensure accuracy and correctness of contents of the book at the time of going to press. However, in view of possibility of human error or changes in medical science, neither the author, publisher nor any other person who has been involved in preparation of this work accepts any responsibility for any errors or omissions or results obtained from use of information given in the book. The publisher shall not be liable for any direct, consequential, or incidental damages arising out of the use of the book. In case of binding mistake, misprints, or missing pages etc, the publisher's entire liability, and your exclusive remedy, is replacement of the book within one month of purchase by similar edition/reprint of the book. In case of any dispute, all legal matters are to be settled under Delhi Jurisdiction only.

Published by: ARYA PUBLICATIONS (Avichal Publishing Company) 7, Industrial Area, Trilokpur Road Kala Amb-173030, Distt. Sirmour (HP) Delhi Office: 1002 Faiz Road (opp. Hanuman Murti), Karol Bagh, New Delhi-110 005 (India) Phone: 011-28752745, 28752604, 28755383 Fax: 011-28756921 Email: [email protected] Website: www.apcbooks.co.in ISBN-978-81-7855-565-2 © Author First Edition: 2002 Reprint: 2008 Second Edition: 2010 Reprint: 2014 T hird Edition: 2016 Reprint: 2017 Price: t '.!">0.00

Laser Typesetting at: Eltee Printmaster (P) Printed at: Deepak Offset Printers Bawana Ind. Area, Delhi

NOTICE Information contained in this book is uptodate, believed to be reliable when checked with the sources and is in accordance with the accepted standard, at the time of publication. However, with ongoing research and passage of time, new knowledge may modify some of it. The reader should, therefore, approach the book with a realistic attitude (particularly the drugs and doses) and should carry the professional responsibility. The readers are requested to verify the information contained herein from other sources. Neither the publisher nor the author(s)/editor(s) assumes any liability for any injury and/ or damage to persons or property arising from the use of material in this book .

I would like to thank my wife Bhavana for standing beside me throughout my career and helping me in writing this book. She has been my inspiration and motivation for continuing to improve my knowledge and move my career forward. She is my rock, and I dedicate this book to her.

Preface to Third Edition Prime facea, I am grateful to the God for the good health and wellbeing that were necessary to complete this book. Since the last edition of this book was published in the year 2010 I have received numerous email messages and letters from students commenting on the book and suggesting how it could be improved. Based on my own experiences in editing and in examining and supervising theses. I have revised the book and added a few new chapters. My daughter Bhushita provides the perfect blend of knowledge and skills that went into authoring this book. She has added the new chapters and tried to update the procedures. Words can not express my sincere appreciation for her assistance to broaden the perspectives of this book. The most obvious changes in this edition are the new chapters on intervention, Doppler, CT and MR guided procedure. They are assembled into an entirely new chapters which, I sincerely hope, will help the residents. A few of the procedures like bronchography, splenoportography, Myelography have become absolute with the advances in CT and MRI and have been deleted. We have added new chapters and updated some of the existing chapters. Because the students are familiar with the layout of the first edition, we have tried to change it as little as possible. My main audience remain the students. I hope, they will find the procedures presented in this book to be both inspirational and instrumental in tackling new challenges in the field of imaging sciences. I would like to acknowledge the help of my students involved in this project, without their support, this book would not have become a reality. Working with the Avichal staff was once again a pleasure. Their collaboration is greatly appreciated. We thank Dr Vipin Gupta for his patience in guiding us through this new edition. Dr Bhushan N Lakhkar

Preface to Second Edition Due to popularity and success of first edition of this book; it has been decided to cease reprints and move immediately in to the production of the second edition. The aims and layout of this second edition are very similar to those in the first, with improvement being made in each chapter. A new chapter has been added on 'embolizing materials and interventional procedures'. My major concern in this book is to help and encourage the residents to perform all radiological procedures of diagnostic quality and to help the clinicians in reaching the proper diagnosis. I have received a lot of encouragement to prepare this second edition from many residents, who have used this book during their residency training period. I want to thank all my students who had helped me patiently as the book progressed from the crude notes to its present form. Special thanks to Dr. Vipin Gupta, who constantly reminded me to complete this book in time. Finally I must thank may publisher, M/S Avichal Publishing Company, without their support this edition would not have been possible. Dr. Bhushan N. Lakhkar

Contents 1. Contrast Media 2. Intravenous Urogram-1.V.U.

3. Micturating Cystourethrogram (MCU) 4. Retrograde Pyeloureterography

5. Contrast Media in GIT 6. Barium Swallow

7. Barium Meal

8. Barium Meal Follow Through 9. Enteroclysis (Small Bowel Enema) 10. Barium Enema 11. Hysterosalpingography 12. Fallopian Tube Recanalisation 13. Sialography 14. T-Tube Cholangiography 15. Percutaneous Transhepatic Cholangiography 16. Catheters 17. Angiography 18. Phlebography 19. Dacrocystography 20. Interventional Radiology 21. New trends in Radiography 22. Mammography and Sono-Elastography 23. Doppler in Obstetrics and Peripheral Vessels 24. Advances in Interventions 25. CT Procedures 26. MR Procedures 27. Positron Emission Tomography (PET)

1 27 42 47 51 60 66 76 85 97 110 117 121 124 128 134 142 156 162 167 198 212 231 246 262 272 282

Chapter 1

Contrast Media • • • • • • • •

L__

Classification Chemistry Physiology Toxicity Treatment Contrast Media Used in Ultrasound Contrast Media Used in MRI References

CLASSIFICATION

i

Contrast Media (CM)

t

_

Negative CM Air, CO2

t

MRI

Ultra-sound

X-Ray & CT

Positive CM

__,

t

t

Oily CM

Iodinated CM Water soluble

Renal excretion

Hepatic excretion lopanoic acid Calcium lopadate

Low osmolar _J

High osmolar

t

Ionic monomers lothalamate Diatrizoate

t

Ionic dimers loxaglic acid locamic acid

t

Non-ionic monomers Metrizamide lohexol

t

Non-ionic dimers lotrol lotrolan

2 • Radiological Procedures

Iodine 1. Most of the i.v. contrast media contain iodine which has an atomic number 53 and atomic weight 127. 2. Total iodine content in the body is 50 mg. 3. It's preferred because • High contrast density due to high atomic number • Allows firm binding to highly variable benzene ring • Low toxicity. 4. It's not suitable for MRI. Water Soluble Iodinated Contrast Media Classification I. Conventional Contrast Media/High Osmolarnonic Monomers salts of • Diatrizoic acid (Urovedeo, Trazograff, Urograffin, Angiograffin and Contrastin) • Iodamic acid • Ioglicic acid • Iothalamic acid (Conray, Triovideo) • Ioxithalamic acid II. Ionic Dimer salts of • Ioxaglic acid (Hexabrix) • Iocarmic acid III. Non-Ionic Monomer • Iohexol-(omnipaque) • Iopamidol -(Iopamiro) • Ioversol -(optiray) • Iopromide-(Ultravist) • Iopentol IV. Non Ionic Dimer • Iotrol • Iotrolan (Isovist) • Iodixanol Class II, III and IV are collectively known as low osmolar contrast media.

Contrast Media •3

CHEMISTRY I. Conventional Contrast Media/High Osmolar C.M./Ionic Monomers These are salts consisting of a sodium or meglumine cation and a triodinated benzoate anion. • Anions consisting of a benzoic acid molecule with three atoms of iodine firmly attached at C 2, C4 and C6 . • The C3 and Cs are connected to radicals CR3 and Rs, which are amines E-NH2, and greatly reduce toxicity and increase solubility of the molecules. • Iodine particle ratio is 3:2. • Sodium or meglumine act as cations. • Differences between meglumine salts and sodium salts. Meglumine salts Better

Solubility

L

High Better

I Viscosity I Tolerance -

Blood brain barrier No effect Less Vascular effects Strong Diuretic effect Poor Opacification Causes, so Bronchospasm contraindicated in bronchial asthma

Sodium salts Same, less in some acids Low Less, causes nausea and vomiting Crosses (BBB) Marked Less Better No

Examples 1. Diatrizoic Acid • The two side chains, R 3 and Rs in diatrizoic acid are replaced by (NHCOCH3). This - Increases solubility - Decreases plasma protein binding thereby increasing its ability to be filtered in glomerulus - Improves patient tolerance E.g.: Urograffin, Trazograff, Urovision, Urovideo, Angiograf­ fin

4 • Radiological Procedures

2. lothalamic Acid It is obtained by substitution of one of the two nitrogen atoms of the benzene ring by a carboxyl group. It has better neural tolerance but decreased cardiovascular tolerance. E.g.: Conray, Triovideo Disadvantages of Conventional Contrast Media 1. Osmolar concentration (osmolality) is extremely high upto 8 times the physiological level of 300 m osm/kg water. 2. Osmolar challenge to every cell, tissue and fluid in the body is responsible for their adverse effects. 3. The very high osmolarity is due to the fact that the non-radiopaque cations (Na/meg) exert just as great as an osmolar load as do the radiopaque anions. The cation is merely a carrier and serves no radiological function. It would make an excellent sense to have a contrast media with fewer or no non-radiopaque cation. Useful Facts to Remember • Osmolality is dependent on number of particles of solute in solution. • Radiopacity is dependent on the iodine concentration of the solution and is therefore dependent on the number of iodine atoms in each molecule of the contrast medium. • High radiopacity and low osmolality are desirable requirements. • The ratio of the number of iodine atoms per molecule to the number of particles per molecule of solute in solution is therefore a fundamental criterion. • Iodine particle ratio for all conventional high osmolar monomeric contrast media salts is 3:2. • Non-ionicity is essential for myelography and reduces the reactions to LV. injection. II. Low Osmolar Contrast Media Ionic Dimers • Two benzene rings (each with three iodine atoms) are linked by a bridge to form a large compound, e.g., Hexabrix. • This group carries only one carboxyl group. So known as monoacid dimers. • Iodine particles ratio is 6:2.

Contrast Media • 5

Non-Ionic Monomers (NIM) • Carboxyl group (-COOH) at C-1, of monomeric salts is replaced by a nonionizing radical and CONH2 producing an iodine : particle ratio of 3:1. • Metrizamide (Amipaque) was the earliest non-ionic monomer and proved as an excellent contrast media but was very expensive, impossible to autoclave and unstable in solution, so second generation of NIM were included later such as : - Iohexol (omnipaque) - lopamidol (Iopamiro) - loversol (optiray) - lopromide (Ultravist) • Iodine: particle ratio is 3:1. • Osmolality is around 600 mosmols/kg whereas normal osmolality of plasma is 280-303 mosmols/kg.

Non-Ionic Dimers Iodine: particle ratio is 6:1.

E.g. Iotrol; Iotrolan (lsovist). Osmolality is around 300 mosmols/kg which is nearly iso-osmolar to plasma osmolality that is 280-303 mosmols/kg.

Additives Used in Contrast Media 1. Stabilizer-Ca or Na EDTA. 2 . Buffers-stabilizes pH during storage-Na acid phosphates. 3. Preservatives-generally not disclosed by manufacturers. Ideal Contrast Media should have 1. High water solubility. 2. Heat and chemical stability (Shelf life). Ideally-3-5 years. 3. Biological inertness (non-antigenic). 4. Low viscosity. 5. Low or iso-osmolar to plasma. 6. Selective excretion, like excretion by kidney is favourable. 7. Safety : LD50 (lethal dose) should be high. 8. Reasonable cost.

6 • Radiological Procedures

Ionic Contrast Media Available in India are: German Remedies Iodine w/v Diatrizoic-Acid group mg/ml (g/100 ml) Urograffin I 292 52 +8 60% meg+Na I 76% meg+Na 370 66 +10 306 65 Angiograffin Meglumine diatrizoate Urovision 325 40:18 Na: Me

l I

Viscosity at 37° C 4 8.9 5

3.3

Bracco Iod"me mg/ml

v·lSCOSl" ty at

60

280

4

66.8

400

4.5

+

370

8.4

296

4.1

Iodine mg/ml

Viscosity at 31° c

370

8.9

66

282

5.0

41.5+18.5

334

3.4

WV I

(g/100 ml) Iothalamic acid group

Triovideo 280 Me Iothalamate Triovideo 400 Na Iothalamate -

37° c �-

-

-

Diatrizoic acid group

Urovideo 75% meg + Na Urovideo 60% meg+N _ a_ __

68 54.4

8.3

+

6.7

-

I

Unique (JB Chemicals) Diatrizoic acid group

Trazograff Trazogmff 76% Na+meg Trazograff 60% Meg Trazograff plus Na+meg

w/v (g/100 ml) 110+66

+

Contrast Media •7

Non-ionic contrast media available in India are: Bracco lopamidol (Iopamiro)

w/v (g/100 ml)

mg Uml

30.6 40.8 61.2 75.5

150 200 300 370

lopamidol 150 Iopamidol 200 Iopamidol 300 Iopamidol 370

Viscosity at 37°c 1.5 2.0 4.7 9.4

Nycomed-Now GE Healthcare Omnipaque (lohexol) Omnipaque 140 Omnipaque 180 Omnipaque 240 Omnipaque 300 Omnipaque 350

mg Uml 140 180 240 300 350

Viscosity at 37°C 1.5 2.0 3.3 6.1 10.6

Mallinckrodt International Corporation Optiray (Ioversol) Optiray 160 Optiray 240 Optiray 300 Optiray 320 Optiray 350

mg Uml 160 240 300

Viscosity at 37°C 1.9 3.0

320

350

5.5

5.8 6.0

German Remedies Ultravist (Iopromide) Ultravist 150 Ultravist 240 Ultravist 300 Ultravist 370

w/v (g/100 ml) 31.2 49.9 62.3 76.9

mg Uml 150 240 300 370

PHYSIOLOGY Concentration and excretion of these contrast media are predominantly by passive glomerular filtration. Net tubular excretion and protein binding is negligible in the dose used. Liver and Intestine excrete 1 % of these compounds.

8 • Radiological Procedures

After intravascular administration, first it diffuses into the ex­ travascular space (whole body opacification) and is simultaneously excreted. Then equilibrium is reached between intra and extravascular space in 10 min. Continued excretion and reentry of contrast media from E.C.F. to I.CF. lead to decrease in plasma level. Plasma half life is 30-60 min. Contrast media are filtered from blood into Bowman's capsule by passive glomerular filtration. In the Bowman's capsule, plasma concentration of contrast media is the same as in blood. In PCT, resorption of Na and H2O causes 5-10 times concentration of contrast media. If the patient is on diuretics, the concentration does not occur. Further increase in concentration of contrast media occurs by counter current mechanism in the loop of Henle. In OCT by the action of ADH, the concentration of contrast media further increases. Points to Remember 1. Contrast media used for myelography are non-ionic contrast media. 2. Contrast media used for cerebral Angiography, are contrast media containing only meglumine cation. 3. Contrast media containing only meglumine are - Conray 280, Triovideo 280, Trazograff 60% and Angiograffin. 4. Contrast media containing only sodium are - Conray 420, Triovideo 420. 5. Contrast media containing sodium more than meglumine are Urovision and Trazograff plus. 6. Contrast media with least osmolarity are maximum Hexabrix. 7. Contrast media which cause maximum nausea and vomiting are - Hexabrix. 8. Meglumine salts cause bronchospasm, so contra-indicated in bronchial asthma. 9. LD50 - increased LD50 mean more safety: - Iohexol is safest contrast media. E.g.:

Conray 420 Hexabrix Iohexol Iopamidol

LD50 (mouse, I.V. lml/kg) 8

12.5 24.2 21.8

10. In newer contrast media, Iohexol is the most hyperosmolar.

Contrast Media •9

11. Viscosity influences the ease with which contrast media can be injected. Viscosity increases as concentration increases and tends to be higher for big size molecules (Dimers). High viscosity interferes with mixing of contrast media with plasma and body fluids. � Viscosity at � Contrast media ° 20 c 37°c Conray 420 8.1 5.4 Hexabrix 320 7.5 15.7 / Omnipaque 240 5.6 3.3 11.6 6.1 �paque 300 I

Ornnipaque 240 has least viscosity. 12. Incidence of thrombo embolic phenomenon is fairly high when contrast media is mixed with blood. This is higher with Low Osmolar Contrast Media (LOCM). So, meticulous heparinization is required during angiography.

TOXICITY I. Reactions unrelated to contrast media. II. Hyperosmolality. III. Chemotoxic. IV. Immunological.

I. Reactions Unrelated to Contrast Media (i) Pyrogenic (Unsterile injection). Management • Stop injection. • Reassure the patient. • Cover the patient with Blanket. • Once chills occur-change the syringe, contrast and scalp vein set. • No need for medication. (ii) Vasovagal especially in anxious or psychosomatic patient. (iii) Hypertensive attacks in patient with pheochromocytoma. (iv) Excessive dehydration, hypoglycaemia.

"

10 • Radiological Procedures

II. Hyper Osmolarity This is due to the high osmolarity of contrast media than plasma. More with conventional contrast media. These reactions include • Erythrocyte damage. • Capillary endothelial damage. • Vasodilatation. • Hypervolemia. • Cardiovascular effects. • Vascular pain. • Disturbance of BBB. • Thrombosis and thrombophlebitis.

Erythrocyte Damage Injection of hyperosmolar contrast media � Loss of H20 from RBC � Dehydrated shrunken RBC � Increased internal viscosity with loss of ability of RBC to deform to traverse capillaries � Obstruction of important capillary beds (cerebral, coronary, renal, pulmonary).

Capillary Endothelial Damage Hyp erosmolar Contrast media � Shrinkage of endothelial cells � Widening of intercellular gaps � Capillary permeability.

Vasodilatation Vasodilatation of arteriolar beds, is a direct result of perfusion with any hyperosmolar solution. Clinically, this is evident by marked vasodilatation produced on peripheral arteriography. This produces a sensation of heat, which may be uncomfortable and often accompanied by pain, especially in hand and external carotid artery territory.

Hypervolemia This is due to diffusion of extracellular fluid through capillary walls into blood which occurs whenever large volumes of hyperosmolar fluid are injected intravascularly. The extravascular fluid is drawn in so much that the blood volume may increase by 10% within a few seconds. The increased capillary permeability due to endothelial damage, permits intravascular fluid to escape from the capillaries and soon reduces the blood volume towards its original level. Cardiovascular Effects • Peripheral vasodilatation. • Decreased systemic blood pressure. • Tachycardia.

Contrast Media • 11

• Cardiovascular insufficiency. • Acute hypervolemia � Left ventricular stress. • Selective arteriography induces bradycardia and moderate reduction in cardiac output. • Na edetate and Na citrate which are used as preservatives in the contrast media chelate Ca2+, therefore leading to transient hypocalcaemia. This causes negative ionotropic effect on heart.

Disturbance of Blood Brain Barrier The blood tissue barrier in all non-neurological tissues allows molecules to pass freely through the endothelium so that their concentration in both the intra and extravascular fluids becomes equalized within few minutes of injection. The BBB is different. In healthy nervous tissue, the normal capillary endothelium prevents contrast media molecules from free diffusion into extravascular fluid. If the barrier is damaged, the permeability across the barriers is increased and the sensitive neurological cells are directly exposed to potentially neurotoxic substances including contrast media molecules. III. Chemotoxic Action Chemotoxic effects are usually due to the cations. Especially Na+. The effects are seen in • Neurons. • Myocardial cells. • Capillary endothelium. • RBC. • Kidney. Nephrotoxicity of contrast media is due to - Decreased renal perfusion. (low B.P., peripheral vasodilatation). - Glomerular injury - manifest as proteinuria. - Tubular injury - due to osmolarity, chemotoxicity, ischaemia. - Contrast media precipitation of Tamm Horsfall proteins that block tubules. - Swelling of renal tubular cells causing obstruction. IV. Immunological (Allergic) Toxicity Mechanisms • Deactivation of angiotensin converting enzyme. Incidence of adverse contrast media reactions to intra-arterial

12 • Radiological Procedures

• • • •

injection is about l/3rd of incidence following intravenous injection because the latter stimulate release of vasoactive substances from mast cells or deactivates ACE in lung. ACE deactivates bradykinin, the concentration of which rises with IV injection of Contrast media. Due to damage to the endothelium which initiates the activation system which inturn may be responsible for many adverse anaphylactoid reactions. Activation of complement, kinins, coagulation and fibrinolytic systems. Inhibition of cholinesterase with consequent vagal over stimulation� acetylcholine release � collapse, bradycardia, bronchospasm. Release of vasoactive substances like histamine, bradykinin, serotonin.

Anaphylactic Reaction • Occurs in previously sensitized individual.

Anaphylactoid Reaction • Occurs in nonsensitised individual.

Allergic reaction Reactions may be allergic. However some workers do not accept this hypothesis. Reasons for

Reasons against

• Not dose related. • Common in patients with bronchial asthma. • Liberation of histamine from mast cells was experimentally shown.

• May not occur first time. • No antibodies against contrast media detected. • Prior antihistamine does not totally prevent reactions. • Cardiac arrhythmias and arrest do not occur in allergy.

High Risk Group Persons 1. Prior reactions to contrast media - 11 times more prone. 2. History of allergy - 4 times more prone. 3. Cardiac disease - 4 times more prone. 4. Asthma - 5 times more prone. 5. Diabetes - 4 times more prone. 6. Old age - 4 times more prone.

Contrast Media • 13

7. Neonates - 4 times more prone.

8. Myelomatosis, polycythemia. 9. Sickle cell anaemia, pheochromocytoma, homocystinuria.

Premedication for High Risk Group 1. Tab. Wysolone (10 mg) q.i.d. for 2-3 days (Prednisolone).

2. Tab Rantac (150 mg) b.d. for 2 days. 3. On the day of procedure, if necessary. Injection 1 ampoule of Hydrocortisone. Severity of reactions • Minor : 1 in 20 cases - 5%. Nausea, vomiting, mild rash, light headache and mild dyspnoea. Needs no treatment, but requires assurance. • Intermediate l in 100 - 1%. Extensive urticaria, facial edema, bronchospasm, laryngeal oedema, dyspnoea, mild chest pain or hypotension. Requires treatment but generally there is no need for hospitalization. • Severe reactions (l in 2000 - 0.05%). Circulatory collapse, pulmonary oedema, severe angina, myocardial infarction, convulsions, coma, cardiac or respiratory arrest. Requires hospitalization and intensive care. • Mortality - (l in 40,000 - 0.0025%).

Incidence of Reactions with Ionic Contrast Media (ICM) and Non-Ionic Contrast Media (NICM) in General Population. Contrast media reactions

Incidence

ICM

I 3.8 to 12.7%

I

NICM

0.6 to 3.1%

Mortality

1/30,418

1/207,488

In high risk groups serious side effects

0.25%

0.045%

Fatality rates

1/40,000

1/100000-200000

In patients known to have prior 18-20% reaction, reaction rate. With premedication steroids, reaction rate.

Lower

5-6% Lower

I

I

-j

14 • Radiological Procedures

Treatment Whenever contrast medium is being injected, the radiologist must make sure that appropriate equipment for initial treatment of contrast reactions, is kept ready. Two basic rules to be remembered are 1. Make sure that the drugs for allergic reactions are available before injecting the contrast. 2. Never leave the patient unattended after contrast has been injected until examination is complete. No patient will have a serious reaction after 60 min. of contrast administration. General principles in the use of: 1. Oxygen. 2. Epinephrine. 3. Corticosteroids. Oxygen • Oxygen and equipment for assisting ventilation should be readily available. • Current recommendation for use of high dose oxygen is at the rate of 10-12 L/min via face mask. • 02 can be provided at up to 100% concentration. • Currently it is recommended that high concentration of 02 should be administered to any patient in respiratory distress, regardless of his or her pre-existing condition. Epinephrine The most important single medication in treatment of anaphylactoid reaction is epinephrine. • It is a powerful sympathomimetic agent, activates both a and � adrenergic receptors, thereby producing peripheral vasocontric­ tion (a effects), increased cardiac contractility and cardiac rate (�1 effects) and smooth muscle bronchodilatation (�2 effects). • Epinephrine is available in 2 dilutions : - 1 in 1000-consists 1 mg epinephrine in 1 ml of fluid. This is intended for s.c. or i.m. administration. - 1 in 10,000-consists 1 mg epinephrine in 10 ml of fluid. This is intended for i. v. administration. • Epinephrine is administered - s.c. in a dose of 0.1-0.3 ml (0.1-0.3 mg). It can be repeated every 10-15 min. until a total dose of 1 mg is administered.

Contrast Media • 15

- i.v. in the same dose of 0.1-0.3 mg, so due to greater dilution 1-3 ml is injected. • Life threatening complications of epinephrine are hypertensive crisis, myocardial ischaemia and infarction. • It has to be administered carefully in the following patients: 1. with cardiac disease. 2. with hypertension. 3. on �-blockers.

Corticosteroids They do not play a significant role in acute reactions, they may be effective in reducing late reactions, which can be observed as long as 48 hours. after contrast injection. If steroids are to be administered, intravenous doses of 100-1000 mg of hydrocortisone have been recommended. The initial dose can be followed by continuous infusion of 300-500 mg in a 250 ml solution of saline at rate of 60 ml/hr. Assessment of the patients with reactions

Responsive

Check pulse and BP, look at skin for erythema. Auscultate heart and lungs

Mild

Assure the patient

Unresponsive

Start basic life support

Moderate

Start I.V. line-isotonic fluid infusion Oxygen

• Some of the symptoms which can precede severe reactions include. Nausea, emesis, chills, sneezing, red or watery eyes, nasal con­ gestion, feeling of confusion, disorientation or heightened anxiety. • Each of the reactions that occurs has to be identified and treated on its merit.

Mild Reactions Reassure the patient and tell him the reaction will go away. Loosen tight clothing if any. Tell the patient to take a few deep breaths in and out to relax. Stay with the patient and watch until symptoms subside.

16 • Radiological Procedures

Moderate Reactions Skin Reactions • They can occur any where in the body commonly face, neck and chest. • They are usually pruritic. • Usually no treatment is needed. • If pruritus is severe use Diphenhydramine (50 mg) • If patient develops severe diffuse erythema or angioedema use both H 1 and H2 receptor blockers. (Cirnetidine-300 mg in 20 ml). If no response use Epinephrine 0.1-0.3 ml (1 in 1000).

Respiratory Reactions • Causes of respiratory decompensation - Airway and laryngeal oedema - Bronchospasm - Pulmonary oedema Laryngeal oedema management - 02 - Epinephrine - Intubation may be necessary Bronchospasm Mild - 02 10 L/min face mask - metered dose inhaler Albuterol 2-3 inhalation. Moderate - Epinephrine (1 in 1000) 0.1-.3 ml S.C. repeat 10-15 min - Aminophylline - 5 mg/kg LV. slowly over 10-20 min. Severe - Epinephrine - LV. Pulmonary oedema - Elevate head end of bed - 02 10 L/min - Furosernide 40 mg LV. slowly - Morphine, 1-3 mg LV. - Hydrocortisone 100 mg I.V. slowly - Shift to ICU.

Contrast Media •17

Hypotension Mild 1. Release any abdominal compression 2. Elevate legs 3. 02 10 L/min 4. Isotonic I.V. fluids - administer rapidly

Severe -----With bradycardia

Tachycardia

--�

Atropine 0.6-1 mg I.V., slowly Epinephrine - 1-3 ml Repeat 3-5 ---min (110,000) I.V. Maximum up to 3 mg ---- up to 10 ml or Dopamine

-1

Seizures or Convulsions Mild 1. Tum the patient to one side to avoid aspiration. Be sure airway is clear and open. 2. 02 10 L/min.

Severe 1. Diazepam, 5 mg I.V. slowly Hypertensive Crises 1. 02- 10 L/min 2. Nitroglycerine, 0.4 mg tablet sublingually. 3. If no response, Nifedipine - 10 mg capsule, puncture end of capsule and drop sublingually. Monitor B.P. closely. 4. Consider Stat. ECG. 5. If pheochromocytoma, Phentolamine 5 mg I.V. 6. Frusemide 40 mg I.V. slowly. Extravasation of Contrast Material 1. Elevation of affected extremity above the heart level. 2. Ice packs (20 min t.i.d. for 2-3 days) 3. Plastic surgery consultation if • Large volume extravasation (>30 ml ionic or > 100 ml non-ionic) • Skin ulceration or blistering • Worsening symptoms after 2-4 hours. 4. Close follow-up until resolution.

18 • Radiological Procedures

CONTRAST MEDIA USED IN ULTRASOUND

(Contrast agents boost echogenicity of blood) On account of its ubiquity and low cost, ultrasound may soon become the "diagnostic gatekeeper" for other modalities. Its ability to visualize arterial and venous ischaemia, deep pulmonary emboli, the microvascularity of tumors, make it well suited for 21st century medicine. A new wave of U.S. contrast agents make these and other studies possible by increasing the echogenicity of blood, which can heighten the tissue contrast and better delineate body cavities. The parenteral U.S. echo enhancers consist of microscopic gas filled bubbles whose surfaces reflect sound waves. These bubbles are smaller than red blood cells, at less than 8 microns in size. The backscattering effect they create due to the different impedances of gas and liquid increases the echogenicity of blood. The ingredients are not intrinsically toxic. Safety concerns on avoiding gases with a tendency to coalesce and form emboli.

Generations of Echo Enhancers First-Unstabilised bubbles in indocyanine green (can't survive pulmonary passage, therefore used only for cardiac and large veins studies). Second-Longer lasting bubbles coated with shells of protein, lipids or synthetic polymers. Third-Encapsulated emulsions or bubbles, offer high reflectivity. Ultrasound Contrast Agents Ideal Qualities of Ultrasound Contrast Agents • High echogenicity. • Low attenuation • Low blood solubility • Low diffusivity • Ability to pass through pulmonary capillary bed • Lack of biological effects with repeated doses. • Current generation of microbubbles have a diameter from 1 - 5 micrometer.The success of agents depends on the small size and on the stability of their shell. • Also newer ultrasound contrast agent have prolonged persistence in the vascular bed which provides consistent enhancement of the arterial Doppler signal.

Contrast Media • 19

• Also it is possible to perform dynamic & perfusion studies. • The main mechanism for signal enhancement are backscattering, bubble resonance, and bubble rupture that is highly dependent on the acoustic power of the transmitted ultrasound also known as MECHANICAL INDEX.

Different Types of Ultrasound Contrast Agents (A) Tissue specific ultrasound contrast agents Improves the assessment of certain organs like liver, kidney, pancreas, prostate, and ovary by improving the acoustic differences between normal & abnormal portions of organs. • Levovist • Sonovist [Schering] • Sonozoid [Nycomed-Amersham] The bubbles rupture produces a transient pressure wave, resulting in characteristic mosaic pattern from the tissues, which is termed as induced acoustic emission. (1) Levovist • First generation ultrasound contrast agent consisting of galactose (milk sugar) ground into crystals whose irregular surface acts as nidation sites on which air pockets form when suspended in water. • Used in echocardiography in left ventricle functional assessment. • In vascular phase also it can exhibit a tissue or organ specific action. Gets accumulated in liver & spleen & improves detection of focal liver lesion. • Levovist has been developed by SCHERING-AG. The shell stabilizer is galactose/palmitic acid and the gas used is air. (2) Sonovist (From Schering Ag) • A biodegradable synthetic capsule filled with sulphurhexa fluoride. • It is a stable contrast media. • It has an additional hepatosplenic parenchymal phase following the pool phase.Microbubbles are stationary in this phase. • Sonovist has been developed by SCHERING-AG. The shell stabilizer is cyanoacrylate and the gas used is sulphur hexaflouride. (B)

Vascular Ultrasound Contrast Agent: • These are gas microbubbles with a diameter less than 5 to 10 micrometer to pass through lung capillaries and into the systemic circulation.

20 • Radiological Procedures

• These are most likely to be used in imaging of malignant tumours in liver, kidney, ovary, pancreas & prostate. • It is also used in cardiac evaluation. Example:-Albunex & infosan. • Albunex has been developed by MALLINCNODT INC. The shell stabilizer is albumin and the gas used is air. (C) Contrast Agents For Targeted Imaging:

• Improve the image contrast resolution through differential uptake. • High sensitivity & specificity • These agents permit noninvasive detection of thrombus, carcinoma, inflammation& other sites where specific integrins or adhesion molecules are expanded. • Possible targets are molecular makers on thrombus, endothelial cells & leucocytes.

NEWER APPLICATIONS • HSG contrast sonography for evaluation of fallopian tube patency -ECHOVIST • Reflux sonography as an alternative to MCU, detect or excludes VUR - LEVOVIST • Administration of oral contrast agent - KnoRX facilitates uniform echogenicity of contrast filled stomach & adequate visualization of pancreas. Types of Agents Schering produces three parenteral agents: 1. Echovist-First one to be used and contains galactose based microbubbles. 2. Levovist-More stable. Alongwith galactose based micro bubbles. These are coated with a thin layer of palmitic acid. 3. Cavisomes--Gas filled cyanoacrylate microspheres for liver, spleen and lymph node imaging. Clinical Applications • Contrast media can make vascular studies of perfusion and flow in tiny vessels preferable even in machines lacking doppler capability. • Contrast can also define vascular architecture surrounding malignant stuctures, highlighting abnormal vessels. • Can be used to study the fallopian tube patency.

Contrast Media •21

CONTRAST MEDIA USED IN M.R.I. MRI is the modality of choice for study of the central nervous sy stem with its extension into imaging of abdomen, pelvis and musculoskeletal sy stem because of its high spatial resolution, soft tissue contrast and multiplanar imaging. Concurrent development of contrast media has aided the rapid expansion of this technique with increased clinical efficacy. Requirements of an Ideal Contrast Media 1. Image contrast. 2. Tissue specific 3. Low toxicity and stability in vivo 4. Suitable shelf life. 5. Rapid clearance from the target tissue and safe excretion through renal /hepatobiliary routes. MR is unique in that there are multiple parameters responsible for signal intensity. So the contrast agent must have the ability to influence these parameters at low concentration to minimize dose and potential toxicity. Commercial Brands of Contrast Available in India Name of brands Ionicity

_j Non-i�

OMNISCAN

ProHance Gadovist

f

---

Name of brands

Magnevist Dotarem MultiHance

Ionic Ionic Ionic

)

-�

Non-ionic I Non ionic - --+Ionicity

Viscosity (mPa.s at 37°c)

Osmolality (mosm/kg

::� + 1,603

+-

1,35 1,970

4.96

- 1

-7

Viscosity (mPa.s at 37°c)

Osmolality (mosm/kg H2O) 1,960

�::

--�

L

2.9--2

5.3

Mechanism In conventional and CT scanning, image contrast is generated by different attenuation of the X ray beam by the tissues of the body. -

22 • Radiological Procedures

The parameters determining MR signal intensity and contrast are: 1. Spin density 2. Relaxivity. 3. Magnetic susceptibility. 4. Diffusion and perfusion. 1. Spin Density This cannot be significantly altered by a contrast agent, hence has received less attention. 2. Relaxivity

The two relaxivity parameters that are unique to each tissue are Tl and T2. Tl is the longitudinal/ spin lattice relaxation time. T2 is the transverse/ spin relaxation time. Contrast enhancement depends upon the alteration of these two relaxivity parameters. They can be categorised on the basis of relative change each impart on either Tl and T2. (a) Contrast agent that predominantly affects Tl relaxation is referred to as a positive relaxation agent because enhanced Tl shortening leads to increased signal intensity on Tl weighted image . (b) Contrast agent that predominantly affects T2 relaxation is referred to as a negative relaxation agent because T2 shortening causes decreased signal intensity on T2 weighted images. 3. Magnetic Susceptibility Susceptibility describes the ability of a substance to become magnetised in an external magnetic field. (a) Diamagnetic-negligible effect. (b) Paramagnetic (c) Super paramagnetic-Very large positive susceptibility effect (d) Ferromagnetic Tl Relaxation Agents Most commonly used Tl relaxation agents are paramagnetic substances. Of these Gadolinium is the most frequently used. Gadolinium is complexed with various ligands that act as chelating agents. It belongs to the lanthanide metal group. It has a high spin contrast number which produces a desirable relaxivity contrast agent.

Contrast Media •23

Three agents have been approved by FDA. They are: 1. Gd-HP-D03A : (Gadoteridol/ProHance) - Non ionic : (Gadopentetate dimeglurnine/ 2. Gd-DTPA - Ionic Magnavist) - Non ionic 3. Gd-DTPA-BMA: (Gadodiamide/Ornniscan) • These function as extracellular contrast agents. • They are rapidly excreted by glomerular filtration with half lives between 1-2 hours. • Agents are distributed only when there is a break in the blood-brain barrier/in the slowly flowing veins. • These agents also cause T2 shortening but only at higher doses. • As these compounds are excreted by renal excretion, caution should be exercised in renal impaired patients. • 3-5% of adverse reactions in the form of nausea. Dose---0.1-0.3 rnrnol/kg body weight

T2 relaxation agents Eg. SPIO-Ferrite particles incorporated by super-para magnetic agents. Of the Ferrite particles, Magnetite(Fe304) is used commonly. These are crystalline oxides with particle size ranges from 0.5 to 1 micron and are used in the study of the liver, spleen and GIT studies. 4. Diffusion and Perfusion Mechanism of action Ferrite particles are taken up by phagocytes of liver and spleen where they cause rapid dephasing and hence decreased signal intensity. Therefore, any metastatic deposit can be seen as higher signal intensity. Hepatobiliary chelates 2 gadolinium chelates with hepatobiliary excretion are • Gd-BOPTA & Gd-EOB-DTPA • MnDPDP (Mangafodipir trisodium) Both dynamic and delayed scans can be done Blood pool chelates eg. AMI-227 Reversibly binds to plasma albumin achieving a substantial improvement in magnitude and duration of blood pool enhancement.

24 • Radiological Procedures

Particulate agents/susceptibility agents • SPIO • USPIO • Magnetite Predominantly have T2 effects.

Newer applications 1. Spin density contrast agents like Perfluoroctyl bromide (PFOB)­ can be used as negative contrast enhancement agents. 2. Using magnetisation transfer, enhancement caused by gadolinium can be better appreciated. 3. First pass studies with 1.5 T or Echoplanar units by observing the T2/ T2* effects of a contrast agent can make assessment of blood flow and brain perfusion. 4. High dose applications-around O.3mmol/kg. body wt for better detection of lesions. 5. Dysprosium chelates for T2/T2* effects of contrast medium is observed during bolus transit. Ionic (Gd-DTPA)

Intravenous

Non ionic (Gadodiamide)

Gd-Labeled Albumin � lntravascu.:.::::.._i Chromium-Labeled Red Blood Cells

1

Hepatobiliary MRI Contrast AGents

Chromium-Labeled Red Blood Cells

1� Manganese Chloride Chelates:

Tumor Specific - Monoclonal Antibodies/Metalloporphyrins/ Nitroxides/Ferrioxamine Gadolinium Oxide Reticuloendoth

Superparamagnetic Iron Oxide Liposomes

Gastrointestinal I

Positive Contrast Agents: Paramagnetic Agents/Short H-relaxation Agents/Combination Contrast Agents Negative GI Contrast Agents: Diamagnetic Contrast Agents/Superparamagnetic Contrast Agents/ Perfluorochemicals

Contrast Media •25

Short Answer Questions 1. Give examples of few ionic monomers and dimers used in diagnostic radiology. 2. Give examples of few non ionic monomers and dimers used in diagnostic radiology. 3. Why low osmolar contrast media is preferred for imtravenous urography studies? 4. Enumerate the features of an ideal contrast media? 5. How will you treat a patient who developed shivering following intravenous injection of a contrast media? 6. Why do we get reactions when the same contrast media is injected by intravenous route as compared to intra-arterial route? 7. In which patients non ionic contrast media are preferred as compared to ionic? 8. What drugs should be available in the emergency tray when you perform intravenous urography examination? 9. Discuss in brief about commercially available ultrasound contrast media. 10. Enumerate different contrast media used during the Magnetic resonance evaluation. What are the organ specific contrast media?

REFERENCES

1. Larser EC. Contrast media for urography. In: Pollack HM (ed). Clinical urography-An atlas and textbook of urological imaging, pt edition. Philadelphia: WB Saunders, 1990: 23-26. 2. Stanley Baum, Michael J Pantecost, eds. Abram's angiography: Interventional Radiology, vol.I, 4 th ed. Boston: Little, Brown, 1997: 13-48. 3. Bettrnann MA. Ionic versus non-ionic contrast agents for intravenous use: Are all answers in Radiology 1990; 175: 616. 4. Cohan RH, Leder RA. Treatment of adverse reaction to radiographic contrast media in adults. Radial Clin North Am 1996; 34: 1055-1076. 5. Cohan RH and Dunnick NR. Intravascular contrast media: Adverse reactions. AJR 1987; 149: 665. 6. Siegle RL and Liebieman P. A review of untoward reaction to iodinated contrast material. J Urol 1978; 119: 581. 7. Buem NP. Contrast agents for ultrasound imaging and Doppler. In: Rumack CM, Wilson SR (eds). Diagnostic ultrasound, 2nd edn. St. Louis: Mosby, 1998: 57-82.

26 • Radiological Procedures

8. David D Stark, William G Bradley, Jr-MRI Vol. 1, 3rd edition, Mosby 1999, Pg No. 257-275 9. RCNA-Hepatic imaging-Liver specific MR Imaging contrast agents -March 1998:36-2,287-298 10. Robert E Edelman , Micheal B Zlatkin, John R Hesselink Clinical MRI Vol 1. 2nd edition WB Saunders Company 1996:177-191. 11. Scott W Atlas-MRI of Brain and Spine , 2nd edition, Lippincott­ Raven 1996-page 89-108.

Chapter 2

Intravenous Urogram-1.V.U. • • • • • • • • • • • • • •

Indications Contraindications Risk Factors Contrast Media Preparation Procedure Filming Technique Nephrotomogram Modifications of Urogram Complications After Care Ct Urography Mr Urography References

It is the radiographic examination of urinary tract including renal parenchyma, calyces and pelvis after intravenous injection of contrast media. Intravenous pyelogram (IVP) is a misnomer as it implies visualisation of the pelvis and calyces without the parenchyma. The term pyelogram is reserved for retrograde studies visualising only the collecting system. There has been a decline in the intravenous urograms done over the last 10 years. This is because of 1. Development of newer imaging modalities like CT Scan, Ultrasound etc. 2. Cost--containment. 3. Adverse effects of contrast media.

27

28 • Radiological Procedures

INDICATIONS In Adults 1. Screening of entire urinary tract especially in cases of haematuria or pyuria. 2. Diseases of renal collecting system and renal pelvis. 3. Differentiation of function of both kidneys. 4. Abnormalities of the ureter. 5. Obstructive uropathy-IVU is the gold standard. 6. TB of the urinary tract. 7. Calculus disease. 8. Potential Renal Donors. 9. Prior to endo-urological procedures and surgery of urinary tract. 10. Suspected renal injury. 11. Renal colic or flank pain.

In Children Besides the indications mentioned above other indications are 1. VATER anomalies: These patients have vertebral, anal, tracheo­ oesophageal, and renal anomalies. Renal anomalies are seen in about 90% of patients. 2. Malformation of urinary tract, e.g., polycystic disease, PUJ obstruction etc. 3. Neurological disorders affecting urinary tract. 4. Malformation of genitalia like bilateral cryptorchidism, III degree hypospadiasis, family history of urinary tract anomalies, urinary tract infection. 5. Enuresis in the presence of bacteriuria, abnormal urinary sediment, adolescents, diurnal/ nocturnal incontinence and history of recurrent urinary tract infection. 6. In girls with constant or intermittent dampness which suggests an ectopically inserted ureter, IVU is mandatory. 7. Anorectal anomalies. 8. Not recommended for evaluation of UTI unless preliminary voiding cystourethrogram reveals reflux or some other compelling indication. CONTRAINDICATIONS (RELATIVE) 1. Iodine sensitivity. 2. Pregnancy.

Intravenous Urogram-I.V.U. • 29

3. Severe history of anaphylaxis previously carries 30% risk of similar reaction on a subsequent occasion. The risk is lower with low osmolar contrast media.

RISK FACTORS l. Cardiac failure: For patients in cardiac decompensation, hyperosmolar contrast should not be used as the media intensify the congestive cardiac failure. Low osmolar contrast media like Iohexol should be used. 2. Dehydration : Renal shut down may be precipitated especially in infants, diabetics and in multiple myeloma patients as it causes protein precipitation (Tamm Horsfall and Bence Jones Protein) in renal tubules and results in anuria. Dehydration can cause thrombosis of renal vein and renal failure in children. 3. Diabetes with Azotemia: These patients are prone to nephrotoxic contrast media effects. 1 in 2000 patients can develop renal shut down. 4. Previous allergic reaction: In these cases, non-ionic agents should be used and injectable steroids should be given 12 and 4 hours before procedure. 5. History of Pheochromocytoma: Contrast media can precipitate hypertensive crisis. CONTRAST MEDIA Doses In adults Non-ionic contrast media Iohexol-Omnipaque 300 mg I/ml-40-80 ml or 350 mg I/ ml 40-80ml Ionic media 300 to 600 mg Iodine equivalent/kg body weight. Maximum of 40 gm of Iodine.

In children

I

240 mg I/ml 300mg I/ml < 7 kg 4 ml/kg 3 ml/kg > 7 Kg 3 ml/kg 2 ml/kg

Meglumine iothalamate or diatrizoate 60% containing equivalent of 280 mg I/ I ml of iodine. Dose is 1-2 ml /kg body weight < 6 months 10 ml 6 months-2 yrs 20 ml 20-40 ml. 2-10 yrs

30 • Radiological Procedures

Mode of injection Contrast media is usually given as a LV. bolus injection within 30-60 seconds. The density of the nephrogram is directly proportional to the plasma concentration of contrast media. More iodine increases the density of the nephrogram. Large doses of contrast media increase diuresis which distends the collecting system thus increasing the diagnostic information from the urogram.

PREPARATION For Adults 1. Ask for any history of Diabetes mellitus, Pheochromocytoma, Renal disease, or allergy to drugs and any specific foods. 2. Fasting for 4 hours. 3. Do not dehydrate the patient. 4. Bowel preparation: • Low residue diet like Dal-chapati/Non-vegetation food and plenty of oral fluids. • Bowel wash is given till bowel is clear of faecal matter on the previous night. Conventional enema is not desirable because it is inadequate for colon cleansing and leave residual air and fluid in the bowel. However, distal colon enemas can be used to clean the distal bowel and can be utilised in the place of 'he suppository. • Laxatives is recommended to eliminate faecal matter from the colon and to reduce amount of gas in the bowel. Dulcolax (Biscodyl) is given 2-4 tablets at bedtime for 2 days prior to the I.V.U. If this does not cause adequate bowel cleansing then give castor oil. Castor oil is an effective catharsis when administered in the dose of 30-60 ml. Castor oil is contraindicated in cases of abdominal pain of unknown cause, old and debilitated patients. In older patients it is advisable to use a suppository in the morning in addition to oral laxatives.

For Children 1. No paediatric patient should ever be purposely dehydrated as it is hazardous to do so. 2. Colon should be empty for I.V.U. For this, laxatives can be given. However, results of laxatives are unpredictable and the compliance

Intravenous Urogram-1.V.U. • 31

in their administration by parents is erratic. Suppositories are better for this purpose. Cleansing enemas are used in children older than 2 years. A preliminary film is taken. If it shows undue gas or faeces in colon the nurse can administer a cleansing enema using soap suds. 3. The child posted for urography must not have a full stomach to avoid vomiting. So the child should not be given anything by mouth for 3-4 hours prior to the procedure.

PROCEDURE

• Patient is placed in supine position with pelvis at cathode side of the tube. • A support is placed under patient's knees to reduce lordotic curvature of lumbosacral spine and provide comfort. • A scout film is taken including the kidneys, ureters, bladder and urethral regions on a large size film. Contrast media is injected intravenously into a prominent vein in the arm. Test injection of 1ml of contrast is given and patient is observed for 1 min to look for any contrast reactions. Then the rest of the contrast is rapidly injected within 30-60 seconds. Cortical nephrogram is seen within 20 seconds of contrast injection. This depicts the renal parenchyma opacified by contrast. The nephrogram is made up of cortical phase due to vascular filling and a tubular phase due to contrast within the lumen of renal tubule. Density of the nephrogram depends on the dose of contrast and the peak plasma level. The appearance of pyelogram (contrast in calyces) is seen 2 minutes after contrast injection. During its transit, it may be concentrated as much as 50 times producing a dense pyelogram. If a kidney fails to excrete detectable amount of contrast media into collecting system, it is termed as non-visualising kidney. This does not necessarily mean that the kidney is not functioning.

In Children

• Equipment should be capable of short exposures to avoid motion blurring. • Usually a moving grid is used. • Source to image distance- 40 inches or 1 metre. • Contrast - non-ionic best.

32 • Radiological Procedures

• Dose 1-2 ml/kg. • Filming: The concentrating ability of the kidney is not fully developed in neonates, so delay is given for initial films. First film is taken 15 min after. Adequate collimation should be used so as to reduce total absorbed dose and effect of scattered radiation on film quality. Fast film-screen combinations and minimum number of films should be taken. • Gonadal protective shields should be used. • If bowel gas obscures the renal region, either paddle compression technique should be used or place the child in prone position as it displaces bowel away from the kidneys or use post compression release technique.

FILMING TECHNIQUE Low KV (65-75) high mA (600-1000) and short exposure should be used to get optimum image contrast. Standard Films Taken • Plain X-ray KUB /Scout film-14" x 17" • 1 minute film-10" x 12" • 5 minute film-10" x 12" • 10 minute film-15" x 12" • 15 minute film-15" x 12" • 35 minute film-14" x 17" • Post void film-10" x 8" Plain X-ray KUB /Scout film provides valuable information and sometimes indicates probable diagnosis. Useful in assessing • Calculus • Intestinal abnormalities • Intestinal gas pattern • Calcification • Abdominal mass • Foreign body 1 minute film shows nephrogram. This radiograph is often omitted as the renal outlines are usually adequately visualised on 5 minute film. 5 minutefilm shows nephrogram, renal pelvis, upper part of ureter. Compression band is now applied on patient's abdomen and the

Intravenous Urogram-I.V.U. • 33

balloon is positioned on anterior superior iliac spine where ureters cross pelvic brim. This is to produce better pelvicalyceal distension.

Compression contraindicated in: 1. Renal trauma 2. Large abdominal mass 3. Abdominal aneurysm 4. After abdominal surgery 5. If 5 minute film shows dilated calyces or if calyces and pelvis are not adequately opacified, obstruction exists and compression band should not be applied If compression is applied, a film is taken after 5 minutes of compression i.e. 10 minute film, centred on kidneys to demonstrate distended collecting system and proximal ureters. 15 minute film: Visualisation of ureter is better in prone position as they fill better. This position reverses the curve of the inferior course of the ureters making it anti-dependent to gravity. Another method to see ureter is modified trendelenberg technique with 15-20 degrees head low tilt with the patient supine. 35 minute film: It gives complete overview of the urinary tract ; kidney, ureter, bladder. Bladder distension can be evaluated. Post void film: Taken immediately after voiding. It is used to assess for 1. Residual urine; 2. Bladder mucosa! lesions; 3. Diverticula; 4. Bladder tumour; 5. Outlet obstruction; and 6. VUR. Note: All films are taken in full expiratory phase only. Special films in IVU l. Oblique view: To project the ureter away from spine and to separate overlying radio opaque shadows mimicking calculi. Oblique views are also used for visualisation of posterolateral aspects of bladder; differentiation of extrinsic or intrinsic renal, ureteral or bladder masses and for doubtful urethral masses. 2. Erect film is used to • Provoke emptying of urinary tract; • Demonstrate layering of calculi in cysts and abscesses; • Detect urinary tract gas not seen in other films; • Have optimum demonstration of renal ptosis, bladder hernia, cystocele and areas of obstruction in ureter.

34 • Radiological Procedures

3. Prone film is used for • Viewing of ureteral areas not seen in supine films, • Demonstration of renal ptosis and bladder hernia. 4. Delayed films in IVU are taken 1-24 hours after injection. Patients should always be instructed to void prior to delayed films so that a calculus in the distal ureter is seen well. Usual sequence of delayed films is after 1 hr, 3hrs, 6 hrs, 12 hrs and 24 hrs. Delayed films are used in • Cases of obstruction where early nephrogram is seen but collecting system is not seen. • Long standing hydronephrosis in which renal parenchyma is seen but collecting system is not visualised until many hours later. • Congenital lesions like non-visualised upper calyceal system with ectopic or obstructed ureter.

Filming in Children • Films are taken at 2min. (supine) and 7 min. (prone) after contrast administration. Further films are taken depending on the case. • To improve visualisation of left kidney, child can be given a carbonated beverage as gas filled stomach displaces bowel. If not adequate, right posterior oblique view is taken to show the left kidney. • The right kidney can be well seen through the liver in a 15-20 degree caudal tilted view. • In most of the cases one preliminary and two post contrast films will be sufficient. In neonates, excretion of contrast media is delayed and prolonged in the first month of life due to immaturity of the tissue. The concentration of the contrast is also relatively poor. NEPHROTOMOGRAM This consists of rapid injection of contrast media followed by tomography. Indications 1. Mass lesion of renal parenchyma--cysts/tumours.

Intravenous Urograrn-1.V.U. • 35

2. Demonstrate damage to renal parenchy ma from infection or infarct. 3. Exact localization of the mass. 4. Detection of parenchy mal scars. 5. Adrenal tumours. 6. Anomalies-horse shoe kidney, pelvic kidney. 7. Poor contrast concentration. 8. Renal trauma. Technique Patient is placed supine on X-ray table. Preliminary tomograms are taken 6 cm and 9 cm from table top and contrast is injected rapidly. For nephrotomogram body sections are taken at 1cm intervals, 60-90 seconds after end of injection. The tomograms should be taken at the period of maximum intensity of nephrogram. Tomogram levels 8, 9, 10 cm from table top for normal adult. 9, 10, 11 cm in heavier patient. 7, 8, 9 cm in thin patient. 5, 6, 7 cm for children. • Linear tomogram is superior to complex motion tomography. 4050 tube arc gives the best tomographic effect. • Since upper poles of the kidneys are located more posteriorly than the lower poles, upper poles are seen better in posterior tomograms and lower poles on anterior tomograms. • A nephrotomogram at 12-20 seconds after commencement of contrast injection (Arm-Kidney time) may demonstrate a vascular phase with delineation of renal vascularity. • A tomogram at 30-45 seconds shows dense parenchymal opacification, delineation of cortex, medulla, corticomedullary junction and also lobar anatomy of kidney. • A series of tomograms (1-4 minute) shows homogeneous uniform, increased density of parenchyma and no delineation of cortex and medulla. For obliteration of bowel gas, 8-10 degrees tube arc (Zonogram) is used.

36 • Radiological Procedures

MODIFICATIONS OF UROGRAM 1. Diuretic urogram • It is useful when intermittent obstruction is suspected but cannot be confirmed by standard urogram. Therefore the use of diuretics shows an acutely developing hydronephrosis if true intermittent hydronephrosis is present. • I.V. frusemide is used to induce diuresis which distends the renal pelvis. The dose of Lasix is 0 .3-1 mg/kg in adults and 0.5 mg/kg in children. • The film is taken 5-10 minutes after administering the diuretic. 2. Tailored urogram • It modifies the urogram to provide the information needed to include or exclude the clinical problem and tailor the urogram for that. The study is terminated as soon as the desired information is available. 3. Hypertensive urogram • It is also called minute sequence urogram. Films are taken 1, 2, 3, 5 minutes after injection of contrast media. Although the findings are of value, IVU cannot be used for screening of hypertensives as there are many false positive and false negative results. 4. Drip infusion urography • Contrast is given in 500 ml normal saline. Now, this procedure is not widely used. Advantages • Nephrogram persists for longer time. • Enhanced diuresis from the additional contrast media and water volume will distend the collecting system and ureters more fully. • Collecting system is visualised for longer times. • No significant increase in contrast reactions. • Ureteral compression need not be used because excellent ureteral visualization is usually obtained. • Administration is easy. Disadvantages • Overloads the patient with more Iodine than necessary. • Calyceal blunting may be produced, suggesting abnormal dilatation.

Intravenous Urogram-1.V.U. • 37

• May lead to pyelosinus extravasation and pain in patients with partial obstruction. • Increased diuresis may decrease visualization if there is low fixed specific gravity. • May cause CCF in patients with borderline cardiac complaints. • An initial vascular nephrogram is not obtained.

5. Limited urography • The procedure is useful for follow up of earlier pathology. Films taken : KUB; 15 min; Post void 6. Emergency urography • It is done in cases of urinary colic. Films taken : KUB; 15 min 7. High dose urography Indications - Renal failure - Ureteric Obstruction - Emergency Urography - Cystourethrography - Suprarenal tumors - Inadequate bowel preparation - Retrocaval ureter - Vesical fistula - Percutaneous Nephrostomy - Poor bowel preparation • Used in mild renal impairment, it provides more information about calyces than on US/CT. • If US/CT cannot exclude obstruction (e.g., in presence of multiple cysts). • The unfavourable effect on urogram of decreased GFR and impaired renal concentration in renal failure, can be counteracted by increasing contrast medium dose to 600 mg I /kg, i.e., double the normal dose. • Patient should be well hydrated with normal metabolic and CVS function at the time of the procedure. In some with impaired renal function, there is an increase in serum creatinine following IV contrast.

38 • Radiological Procedures

• Low osmolality non-ionic contrast media are preferred because of less nephrotoxicity. • IVU can be attempted up to a serum creatinine level of 5 mg% (preferably using non-ionic contrast). • Risk factors for the development of ARF after HDU : - Diabetes - Dehydration or fluid restriction before urogram - Myxedema - Repeated contrast procedures in a short period of time. - Large doses of contrast - Age > 60 yrs.

COMPLICATIONS Due to Contrast • Minor reactions (5%): Nausea, vomiting, mild rash, light headache, mild dyspnoea. • Intermediate reactions (1 %): Extensive urticaria, facial oedema, bronchospasm, laryngeal oedema, dyspnoea, hypotension. • Severe reactions (0.05%): Circulatory collapse, pulmonary oedema, severe angina, myocardial infarction, convulsions, coma, cardiac or respiratory arrest.

Due to Technique • Upper arm or shoulder pain. • Extravasation of contrast at the injection site.

Initial treatment • Elevation of affected extremity above the heart. • Ice packs (15-60 minute applications three times per day for 1-3 days). • Close observation for 2-4 hours (if volume exceeds 5 ml). • Call referring physician (for any extravasation over 5 ml). • Local injection of hyaluronidase (15-250 IU)-controversial.

Intravenous Urogram-I.V.U. • 39

Immediate plastic surgery consultation for the following indications: • Extravasated volume exceeds 30 ml of conventional ionic or 100 ml of non-ionic contrast material. • Skin blistering. • Altered tissue perfusion (decreased capillary refill over or distal to injection site). • Increasing pain after 2-4 hours. • Change in sensation distal to site of extravastion.

Daily phone calls by nurse or radiologist until manifestations resolve to assess for the following: • • • • •

Residual pain. Blistering. Redness or other skin color change. Hardness. Increased or decreased temperature of skin at extravasation site (compared with temperature of skin elsewhere). • Change in sensation.

Documentation • Contrast material extravasation form (for departmental monitoring and quality assurance). • Progress note (for medical record). • Abdominal compression may cause hypotension/ syncope, forniceal rupture of the calyces. • Rarely extravasation of contrast in perinephric retroperitoneal space may occur as a consequence of which, a perinephric abscess and phlegmon may form if the urine is infected.

AFTER CARE 1. 2. 3. 4.

Observation for 6 hours. Watch for late contrast reactions. Prevention of dehydration. In high risk patients-renal function tests should be done to watch for deterioration.

40 • Radiological Procedures

MR OROGRAPHY MR Urography techniques for visualizing urinary tract are mainly divided into 2 categories: 1. Static fluid urography: Here heavily T2-weighted sequences are obtained to image the urinary tract. It is most useful in patients with dilated or obstructed collecting systems 2. Excretory MR Urography: It is performed during the excretory phase of enhancement after IV administration of Gadolinium based contrast material. For this technique, the patient must have sufficient renal function to MR Urography allow the excretion of contrast material. Diuretic administration is an important factor in MR Urography for better demonstration of non- dilated systems. Advantages of MR Urography: 1. Useful in pediatric and pregnant patients as ionizing radiation is avoided 2. Evaluation of the renal vasculature (artery and vein) is possible Disadvantages of MR Urography: 1. Cost factor 2. The results are not encouraging in evaluation of the renal calculi.

Long Answer Questions----------------1. Define intravenous urography. What are contraindications and preparation required urography? Describe the procedure in brief.

the for

Short Answer Questions---- - - - - --

indications, intravenous

---

-

1. What are the indications for intravenous urography in adults and in children?

Intravenous Urogram-1.V.U. • 41

2. What precautions will you take while performing intravenous urography in patients with cardiac failure and multiple myeloma? 3. What contrast media are used in adults and children while performing intravenous urography? What is the dose of contrast media injected? 4. How will you prepare a patient for intravenous urography? 5. What is compression band? what is its use in intravenous urography? state the contraindications for using compression bands. 6. What are the special views taken in intravenous urography for • visualizing ureter • calculi in cyst • renal ptosis 7. How will you modify intravenous urography in following conditions • hypertension • intermittent obstruction • urinary colic 8. State the complications of intravenous urography due to contrast and due to technique.

REFERENCES

..

1. Nicholae Papanicolau. Urinary tract imaging and intervention : Basic principles. In : Walsh PC, Retik AB, Varghan ED, Wein AJ (eds) : Campbell's Urology, 7th ed. Philadelphia : WB Saunders, 1998: 172-188. 2. JS Dunbar. Excretory urography. In : Pollack HM (ed). Clinical urography-An atlas and textbook of urological imaging, 1st edition. Philadelphia : WB Saunders, 1990 : 101-202. 3. Radiological investigation of the urinary tract. In : Elkin M (ed). Radiology of the urinary sy stem, 1st ed. Boston: Little, Brown, 1980 : 2-22. 4. Diagnostic uroradiologic techniques. In : Alan J. Davidson, David S. Hartman DS (eds). Radiology of the kidney and urinary tract, 2nd ed. Philadelphia : WB Saunders, 1994 : 3-19. 5. Williamson B Jr., Hartman GW. Intravenous urographic technique. Radiology 1988; 167 : 593-599. 6. M Noroozian, RH Cohan etal: Multislice CT Orography: state of the art. British Journal of Radiology (2004) 77, S74-S86. 7. Akira Kawashima, Terri J Vrtiska etal: CT Urography. Radio Graphics 2004; 24: S35-S54. 8. Verswijvel Geert, Oyen R: Magnetic Resonance Imaging in the Detection and Characterization of Renal Diseases. Saudi Journal of Kidney Diseases and Transplantation. Year 2004. Volume 15. Issue 3. Page 283-299 .

Chapter 3

Micturating Cystourethrogram (MCU) • • • • • •

Indications Contrast Media Procedure Complications Other Techniques References

Urethrography is of 2 types: 1. Asending - where contrast is injected into the urethra. It is mainly used to demonstrate anterior urethra. 2. Desending - Similar to MCU - used to demonstrate Posterior urethra Voiding cystourethrogram demonstrates the lower urinary tract and helps to detect the existence of any vesico-ureteral reflux, bladder pathology and congenital or acquired anomalies of bladder outflow tract. INDICATIONS Children 1. UTI-Usually done after some weeks after acute stage or may be done under antibiotic coverage. MCU is indicated after the 1st occurrence of UTI in boys or girls. 2. Voiding difficulties like dysuria, thin stream, dribbling, frequency, urgency. 3. Vesico ureteric reflux. 4. Other congenital anomalies : Meningomyelocele, Sacral agenesis, Rectal anomalies. 5. Baseline study prior to lower UT surgery. 6. For post operative evaluation of ureteric abnormalities. 7. Pelvic Trauma.

Micturating Cystourethrograrn (MCU) • 43

8. In renal failure to exclude reflux. 9. Boys with hematuria-MCU can demonstrate posterior uretheral valve or polyp.

Adults Main indications 1. Trauma to urethra. 2. Urethral stricture. 3. Suspected urethral diverticula. Other indications 1. UTI. 2. Reflux nephropathy prior to renal transplant of one/both kidneys. 3. Follow up of patients with spinal cord injury.

CONTRAST MEDIA Water soluble constrast media like Conray 280, Trivideo 400 mg, Urograffin 60% are used which is diluted with normal saline in 1 3 ratio.

PROCEDURE Using sterile technique, a catheter is introduced into the bladder. A SF feeding tube with side holes are used for children and in older children SF or lOF polyethylene or soft rubber catheters with end holes are suitable. In girls after an initial inspection of the perineum to identity any local genital abnormalities (like cystoceles, or labial fusion etc.,) the urethral catheter is inserted. W hen it enters the bladder a varying amount of urine will flow through it. If there is no flow the catheter is advanced until urine is obtained. Suprapubic pressure is sometimes helpful in expressing a small amount of urine in the near empty bladder. If no urine is obtained the catheter may have been inserted into the vagina. In males, the foreskin is retracted and catheter is introduced. The catheter should be lubricated with an anaesthetic jelly and inserted slowly and gently into the urethra holding the penis in a vertical position. The normal bladder capacity in children is estimated in ounces

,.

44 • Radiological Procedures

(1 ounce = 29 cc) as age (in years) x 2. In the bladder of newborns, 30-50 cc can be instilled with ease. From about 3 years, girls can hold upto 200-250 cc and from 12 years even more. The capacity in boys is, 100-150 cc upto 5-6 years of age and 250 cc in older boys. Adequate capacity is reached when the child becomes uncomfortable and begins voiding around the catheter.

Filming In children In children up to the age of 2 yrs bladder is filled by hand injection. For older children contrast medium is instilled from a bottle elevated one metre above examination table. During filling, fluoroscopic screening is performed at short intervals to see if vesicoureteral reflux, diverticuli or other abnormalities are present. The child is turned oblique on both sides to ensure that minimal reflux is not overlooked. If reflux appears, films are taken in the appropriate oblique projection. If the bladder appears normal, one film is taken in the frontal projection at the end of filling. Voiding starts in infants the moment the catheter is removed. At the end of voiding, a frontal film is made of the entire abdomen including the kidney region in order to prevent overlooking the vesicoureteral reflux which is apparent only on termination of voiding and may reach the upper collecting system. In adult male Bladder is filled in the usual way as in a older child and voiding filming is done in both oblique projection. The voiding study in male adults can be modified by getting the patient to void against resistance, i.e., either by compression of the distal part of penis or by using a penile clamp. This is known as CHOKE CYSTOURETHROGRAPHY which enhances visualization of urethera by the artificial distension. In adult female The procedure is essentially the same as in girls. In addition to the standard exposures, a double exposed film taken at rest and during straining demonstrates the degree of bladder descent if any.

...

Micturating Cystourethrogram (MCU) • 45

COMPLICATIONS 1. Danger of attendant infection due to catheterization of bladder. 2. Adverse reactions may result from absorption of contrast medium by bladder mucosa. 3. Due to technique: • Acute urinary tract infection. • Catheter trauma causing dysuria, frequency hematuria and urinary retention. • Complications of bladder filling, e.g. perforation by the catheter or from over distention. • Catheterization of vagina or ectopic ureteral orifice. • Retention of a Foley's catheter. • Radiation effect: VCU is a diagnostic procedure that inevitably exposes gonads to some radiation. It should be kept to a minimum. Careful attention to ensure very short screening periods. Tightly collimated X-ray beam. 4. Autonomic dysreflexia: In paraplegic patients due to spinal cord injury at or above T 6 level, forceful injection of contrast causes severe headache, sweating and hypertension with bradycardia due to forceful opening of the bladder neck. Treat by promptly relieving vesical distension or give diazoxide 3-5 mg/kg. OTHER TECHNIQUES Excretion MCU (MCU followed by IVU) • This method makes use of contrast media accumulated m the urinary blader during intravenous urography. Advantages • Avoidance of physical and psychological trauma of catheterization. • Avoidance of possible infection by uretheral catheterization. • More physiological procedure hence can be more reliable. Disadvantages • Visualization is not usually adequate. • Takes longer time. • Vesico ureteric reflux cannot be visualized properly.

,.

46 • Radiological Procedures

Long Answer Questions---------------1. Discuss micturating cystourethrography. under the following headings: (a) Indications in children and adults (b) Contrast media (c) Procedure (d) Complications

Short Answer Questions---------------1. What do you mean by micturating cystourethrography? What are the indications for performing this procedure in children and adults. 2. Describe in brief the complications of micturating cystourethrography. 3. Write a short note on descending cysto urethrography.

REFERENCES

1. Marjorie Hertz. Cystourethrography. In : Pollack HM (ed). Clinical urography-An atlas and textbook of urological imaging, 1st edition. Philadelphia: WB Saunders, 1990 : 256-275. 2. Walsh PC, Retik AB, Varghan ED, Wein AJ (eds.) : Campbell's Urology, 7th ed. Philadelphia : WB Saunders, 1998 : 188-192. 3. Radiological investigation of the urinary tract. In : Elkin M (ed). Radiology of the urinary system, 1st ed. Boston : Little, Brown, 1980 : 25-32. 4. Papanicolaou N, Yoder IC. Diagnostic morphologic and urodynamic antegrade pyelography. Radiol Clin North Am 1986; 24 : 561-571.

Chapter 4

Retrograde Pyeloureterography • • • • • • • •

�-:" ....., --r-

Definition Indications Contraindications Contrast Medium Procedure After Care Complications Comparison of MCU & RGU With Newer Modalities • References ...::....�-

_

Ii - --,·----

_._....

DEFINITION It is the roentgenographic demonstration of the renal pelvis and ureter by the retrograde injection of radio-opaque material through the ureters.

INDICATIONS 1. Absent or unsatisfactory visualisation of the collecting system on IVU. 2. Unexplained hematuria, when the ureters have not been completely visualised by IVU. 3. Evaluating persistent intraureteral or intrapelvic filling defects on IVU. 4. Demonstrating the exact site of ureteral fistula. 5. Brushing and/ or biopsy of suspected lesions. 6. Evaluating the collecting system in patients who cannot receive intravenous contrast medium

CONTRAINDICATIONS

• Acute urinary tract infection.

•

47

48 • Radiological Procedures

CONTRAST MEDIUM • Ionic contrast media can be used safely, however if there is any specific contraindication like known hypersensitivity etc., Non ionic contrast media may be used. The Ionic contrast media is preferred due to its low cost. The strength of contrast media should be 150-200 mg I/ml. • Contrast media should not be too dense as it will obscure small lesions in the ureters and the pelvis. PROCEDURE Patient Preparation • Bowel preparation with cathartics is not routinely performed. Preliminary Film • Full length supine AP abdomen before the examination is started. Anaesthesia • May be performed under local anaesthesia although general anesthesia is often required. Sterile precautions are mandatory. Technique In the Operation theatre • The surgeon catheterizes the ureter via a cystoscope and advances the ureteric catheter to the desired level. Contrast medium is injected under fluoroscopic control and spot films are exposed. In the X-Ray Department • With ureteric catheter(s) in situ, the patient is transferred from the operation theatre to the X-ray department if necessary. • Urine is aspirated and under fluoroscopic control contrast medium is slowly injected. About 3-5 ml is usually enough to fill the pelvis but the injection should be terminated before this if the patient complains of pain or fullness in the loin. Films Using the undercouch tube (a) Supine PA film of the kidney (b) Both 35° anterior obliques of the kidneys. Low kVp (65-75 kVp) technique is used to visualise calculi and contrast medium.

Retrograde Pyeloureterography • 49

(c) If there is pelvi-ureteric junction obstruction, the contrast medium in the pelvis is aspirated. The films are examined and if satisfactory, the catheter is withdrawn, first to 10 cm below the renal pelvis and then to lie above the ureteric orifice. About 2ml of contrast medium is injected at each of these levels and films taken.

AFTER CARE 1. Postanaesthetic observation. 2. Prophylatic antibiotics may be used. COMPLICATIONS 1. Due to anaesthetic • Complications of general anaesthesia. 2. Due to the contrast medium • Contrast medium can be absorbed from the renal pelvis, giving rise to adverse reactions. However, the risks are much less than with excretory urography. • Chemical pyelitis-if there is stasis of contrast medium. • Extravasation due to overdistension of the pelvis. 3. Due to technique • Introduction of infection • Mucosal damage to the ureter • Perforation of the ureter or pelvis by the catheter COMPARISON OF MRMCU AND RGU WITH NEWER MODALITIES Advantages of MR - MCU and RGU 1. These studies are most valuable to detect congenital anomalies, posterior urethral injuries, and with urethral and periurethral tumours. 2. It is a better imaging modality for assessing the post traumatic pelvic anatomy & non-invasive method for measuring stricture length. 3. It clearly shows the extent of scar tissue as well as prostatic displacement.

50 • Radiological Procedures

4. MR uretherography is more accurate in estimating the length of obliterative urethral stricture than RGU combined with Voiding cystouretherography

Limitations of conventional RGU combined with voiding cystouretherography: 1. It does not provide accurate length of the defect because of poor prostatic urethral filling. 2. It does not provide information regarding extent of fibrosis of corpora spongiosa or prostatic displacement. 3. The stricture length is overestimated if bladder neck does not relax.

Advantages of CT urethrography 1. C.T. voiding uretherography is more comfortable to the patient because it requires adaptation only in one position. 2. Less time consuming; takes only few seconds 3. Comparison of lurninal size & stricture length for follow up is possible. 4. Extralurninal pathology can be detected 5. Good patient compliance 6. Ability to survey whole urinary tract from kidney to urethra.

Short Answer Questions---------------1.What is retrograde pyelography? State its indications and contraindications. 2.Mention the complications of retrograde pyelography . 3.Draw a figure of normal urethra in males. 4.Draw a section prostatic urethra.

REFERENCES 1. Retrograde pyelography. In : Pollack HM (ed.). Clinical urography­ An atlas and textbook of urological imaging, 1st edition. Philadelphia : WB Saunders, 1990 : 101-202. 2. Walsh PC, Retik AB, Varghan ED, Wein AJ (eds) : Campbell's Urology, 5th ed. Philadelphia: WB Saunders, 1986: 325-327.

Chapter 5

Contrast Media in GIT • • • • • • • • • •

Introduction Properties of An Ideal Barium Preparation Advantages of Barium Sulphate Preparation Manufacture Characteristics Influencing Coating Adverse Effects Other Contrast Media Used Contrast Media For CT in GIT Contrast Media For MRI in GIT References

INTRODUCTION The earliest contrast medium used in the GIT was iodised oil (lipiodol). However, due to its oily nature, it did not coat the mucosa. Hence, later, Bismuth sulphate came to be used. At present the contrast medium of choice is Barium sulphate. The reasons for using Barium sulphate for GI studies are (a) Ba has a high atomic number 56. Therefore, it is highly radioopaque (b) Non absorbable, non-toxic. (c) Insoluble in water/lipid. (d) Inert to tissues. (e) Can be used for double contrast studies. PROPERTIES OF AN IDEAL BARIUM PREPARATION 1. High density for optimum study being performed. 2. Stable suspension which does not settle. 3. Should not flocculate with secretions. 4. Low melting characteristics to give a good and stable mucosal coating. 51

52 • Radiological Procedures

ADVANTAGES OF BARIUM SULPHATE PREPARATION 1. Non-absorbable. Therefore Barium does not get degraded throughout the bowel. 2. Suitable for double contrast studies as it coats the mucosa in a thin layer, thus allows the introduction of 2nd or negative contrast agent without significant degradation.

MANUFACTURE Barium sulphate is obtained from the mines by chemical precipitation in order to remove the impurities.

Steps 1. Mined Barium sulphate is reduced to Barium sulphide (soluble). 2. Barium sulphide + Sodium carbonate � Barium carbonate (Poisonous). 3. Barium carbonate + Sulphuric acid � Insoluble Barium sulphate. The particle size can be reduced by processing the powder in a high speed pounding, machine. Average particle size of precipitated barium sulphate ranges from 0.3 µm to � 12 µm . 0.3 µm particles are used along with large particles to enhance coating and suspending properties of large particles. By themselves small particles resist wetting. Particles towards the size of 12 µm are generaly used for low viscosity, high density barium. High density barium contains, a mixture of different sized particles, that also results in increased viscosity. Viscosity can be reduced by the addition of additives and suspending agents, which are proprietary, e.g., microbar H.D. 200% w/v _for double contrast studies of upper G.I. Tract. BaSO4, being insoluble in water, is used in the form of a suspension. The concentration of the suspension is indicated by weight/volume. E.g.: 100% suspension contains 100 gm of BaSO4 in 100 ml of prepared suspension. Dilution There are 3 systems to describe a particular dilution. Weight by weight - wlw suspension Specified weight of Barium sulphate is used and enough water is then added to obtain a certain total weight.

Contrast Media in GIT • 53

E.g.: 30% w/w suspension is to weigh 30 g of Barium sulphate and add 70 g of water to it for a total wt. of 100 g. (1 gm of water = 1 ml of water). Weight by volume - w/v suspension Here a specified weight of Barium sulphate is determined and enough water is added to obtain a certain total volume. E.g.: 80% w/v suspension is to weigh 80gm Barium sulphate and to add enough water to make the total volume upto 100 ml suspension. Volume by Volume - vlv suspension. This system is possible but not recommended. A unit volume of dry barium sulphate can vary considerably, depending on the degree of packing. Thick and thin barium are meaningless terms. Specific gravity: Weight of 1 litre of Barium solution S.G. = ---'-----------Weight of 1 litre of water

Mixing This is a very important step to assure a stable suspension. Use of a high speed and high shear mixer ensures melting of the Barium sulphate particles and also mixes the particles evenly in the suspension. This ensures that the suspension is stable. It should be mixed for atleast 15 min. continuously, to assure stability just before the suspension is administered. Commercially prepared Barium formulations in India are manufactured by M/s. Eskayef Fine Chemicals Ltd. under the brand name of 'MICROBAR' in the following specifications. 1. Microbar paste: 100% high viscosity paste in collapsible tubes. This is a high density, high viscosity preparation used for conventional studies of the pharynx and oesophagus. 2. Microbar suspension: 95% moderate density and viscosity suspension for oesophagus, stomach and small intestinal studies. Marketed in one litre bottles. 3. Microbar HD: 200% high density, low viscosity preparation, supplied in a powder form in a tumbler pack. By adding 70 ml of water to this and shaking the tumbler the desired amount of suspension is formed which is ideal for double contrast studies for oesophagus, stomach and duodenum. Sachets of gas producing powder are supplied with the pack.

54 • Radiological Procedures

4. Microbar for enema : One and five kg packs of powder are available. Desired suspension can be prepared.

How to prepare your own Barium suspension? To prepare one litre of 50% suspension, take a small amount of water (about 200 ml) and add 5 gm of Carboxy Methyl cellulose (C.M.C) to it and mix well. Take 500 gm of Barium sulphate powder and add a little of it at a time to the water, mixing continuously till a thick paste is formed. This will prevent formation of clumps of the barium. To this paste, add enough water to make up the volume of the mixture to one litre and mix it well. Then add the preservatives, antifoarning agents and antacids. The whole mixture should then be mixed for 15 minutes, using a high speed mixer to form a good suspension. This type of preparation should not be diluted, otherwise it will tend to settle. The preparation should also not be stored for a long time. CHARACTERIS TICS INFLUENCING COATING Additives Additives are added to influence the rate of settling, viscosity, charge, mucosal coating, thickness and flocculation. If too much of an additive is used, the viscosity will be so high that the suspension flows only with difficulty. Exact additives added by the manufacturers are kept as a trade secret, but a varied range of additives can be used when we prepare our own Barium sulphate suspension to achieve the required properties. Density The appropriate density is achieved by making the suspension using the required weight of Barium sulphate powder. Measuring Barium powder using cups cannot be a standard preparation because the compactness of filling the cup will vary. In addition the powder at the top of the packet is made up of larger particles and hence will have lesser weight as compared to the powder at the bottom which is finer and more compact. Stability It indicates that the suspension will not settle down when allowed to stand. Suspending agents like Gum acacia or carboxyrnethyl cellulose (CMC) are used to prevent settling. These agents increase the viscosity

Contrast Media in GIT • 55

of the suspension, hence should be used in minimum amount to attain the required stability. T he suspension is considered to be of adequate stability, if it does not settle at the rate of more than 1/10 at the end of 3 hours. CMC is hygroscopic, therefore retains water and prevents settling of the particles. Hence it prevents sedimentation and size of the particle remains the same.

Flocculation Flocculation is the reduction in the number of particles by the formation of larger masses. When the suspension comes in contact with ionic solutions like intestinal or gastric secretion, the suspension will form clumps. To prevent this, antacids are added which will neutralise the gastric acid and prevent flocculation. They will also make the suspension alkaline so that the intestinal secretions which are alkaline will not cause flocculation. Antacids used are • Sodium citrate (commonly used). • Aluminium hydroxide. • Magnesium sulphate. Preservatives Plain Barium sulphate is inert. Since additives are added to it, we get fungal growth. So preservatives are needed. Previously Methyl paraben was used. Now Sodium metabisulphate is used. Antifoaming agents Simethicone or Melthylpolysiloxone are added to prevent formation of air bubbles which mimic polyps (artifacts). They act by reducing the surface tension of the gas bubbles enabling them to coalesce thus facilitating gaseous release. Coloring agent Erythrocin is used. Sweetening agent Saccharine or fruit essences are used to mask the unpleasant chalky taste of barium and produce less nausea. Chocolate is not commonly used because of possible allergic reaction.

56 • Radiological Procedures

ADVERSE EFFECTS 1. Chemical peritonitis due to extravasation of additives of Barium sulphate. 2. Extravasation into bronchial tree, urinary tract and other body cavities will produce inflammation. 3. Barium inspissation in cases of colonic obstruction to form hard stones. 4. Intravascular entry of Barium can cause embolism. 5. Appendicitis-not proved. 6. Barium Encephalopathy. Small amount of Barium can absorbed from the peritoneum in case of perforation j, Circulation j, Concentrates in CSF with detectable levels j, Encephalopathy 7. Previous contrast media extravasated may mimic cancer due to inflammation. Longstanding barium deposits are carcinogenic.

OTHER CONTRAST MEDIA USED Gastrograffin 20 ml of Urograffin 76% + 20 ml of Normal Saline + 2 drops of Sorbitol (melting agent) which gives a better mucosal coating. Mix thorough!y.

Indications 1. Suspected perforation. 2. Suspected fistula. 3. History of recent biopsy. 4. Suspected Lower Intestinal obstruction. 5. Corrosive poisoning. 6. Meconium ileus/plug syndrome. 7. Immediate post operation status.

Non-ionic Contrast Media Low osmolar contrast media give better opacification of the GIT and

Contrast Media in GIT • 57

due to low osmolarity because less electrolyte imbalance and can delineate small intestine better than ionic media due to less dilution. But they are expensive. Oral Cocktail Mixture of Barium sulphate, Magnesium sulphate and a low osmolar non-ionic contrast media. The latter two absorb water into the bowel and dissolve Barium sulphate. Therefore, barium moves very fast in the GIT. Air/CO2 To diagnose intussusception. Water To diagnose Lipomatosis of colon which appears more lucent compared to the water column. CONTRAST MEDIA FOR CT IN GIT Techniques employed in CT are chosen to maximize delineation of normal anatomic structures, accurately identify pathologic processes and ensure optimal utilization and operational efficiency. For Stomach and Small Bowel To a large extent, the sensitivity of CT in diagnosing pathology depends on adequate bowel opacification and distension, as the basic radiopathologic finding in a variety of diseases is thickening of the intestinal wall. Therefore, the gut in question must be distended and filled with a contrast agent. That permits the wall of the bowel to be assessed accurately. The ideal gut contrast agent • Should fill the entire bowel lumen • Should be palatable • Non-irritating to the intestinal mucosa • Should pass rapidly through the GI tract without producing artifacts or stimulating vigorous intestinal peristalsis. • Preferably the contrast media should coat the gut mucosa so that the presence of bowel lesion is detectable when the lumen is not distended. A positive contrast material must increase the CT attenuation

58 • Radiological Procedures

value of bowel lumen atleast by 40HU. This can be done by using dilute solutions of water soluble media or dilute suspensions of Barium sulphate. Conventional BaSO4 suspension are too dense resulting in streak artifacts when administered. The commercial introduction of dilute 1-2% BaSO4 solutions containing special suspending agents has permitted dilute barium to remain homogeneously suspended as it passes through the GI tract. A solution of 2-3% Meglumine diatrazoate increases the CT attenuation value of the gut enough to permit a reliable differentiation from the surrounding tissues. Although water soluble contrast agents pass rapidly through the gut, they do not coat the gut wall and have a poor taste. They tend to become diluted as they reach the terminal ileum and thus the distal small bowel may be poorly demarcated.

Special Techniques • Glucagon injection (0.1 mg iv /im) can be used for reducing gut motility and motion artifacts. • Octapeptide injections to briefly stimulate small bowel peristalsis. • Metaclopramide 10 mg orally, 45 minutes before CT study rapidly empties the stomach and improves opacification of ileum. For Colon Colon and rectum may be opacified using dilute iodinated solutions 1-2% as a 200-600 ml enema. Air contrast studies have been recently advocated as the method of choice to evaluate the colon. This is contraindicated in acute diverticulitis, inflammatory bowel disease or radiation proctitis. CONTRAST MEDIA FOR MRI IN GIT GI contrast agents for MRI are being developed with the dual aims of improving anatomic delineation and permitting better diagnosis of functional disorders. Ideal Characteristics for MRI are Relatively strong with respect to its paramagnetic or super magnetic properties so that small doses are effective. • Chemically stable. • Preferably non-metabolisable and rapidly eliminated. • Inexpensive and easily synthesized. • Non-toxic in doses appropriate for contrast enhancement.

Contrast Media in GIT • 59

Positive Contrast Agents Water soluble: • Ferric ammonium citrate. • Manganese chloride. [e.g., Lumentlance-Bracco] • Metal chelates including Gd-DTPA.

Water immiscible: • Olive oil

Negative Contrast Agents Water soluble: • • • •

CO2 tablets Perfluorocarbons Magnetites Side effects-Relatively safe Castro intestinal side effects are the commonest among the minimal side effects.

Short Answer Questions -

- - - -----------

1. How will you prepare your own barium preparation for examination of (a) Esophagus (b) Stomach (c) Small intestine. 2. What are the Indications for the water soluble contrast media in gastro-intestinal tract? 3. Write a short note on computed tomography oral contrast media.

REFERENCES 1. Jovitac Skucas, Albert A Moss. Contrast media. In : Freeny PC, Stevenson GW (eds). Marguilis and Burhenne's Alimentary Tract Radiology, 4th edn. St. Louis : Mosby, 1989 : 83-87. 2. Jovitac Skucas. Barium sulphate for gastrointestinal use. In: Richard W Katzberg (ed). The contrast media manual. Baltimore : Williams and Wilkins, 1992 : 187-199. 3. Small W.C. ef al. A multisite phase III study of the safety and efficacy of a new manganese chloride-based gastrointestinal contrast agent for MRI of the abdomen and pelvis. Journal of Magnetic Resonance Imaging, July 1999; lO(i): 15-24.

Chapter 6

Barium Swallow • • • • • • •

Indications Relative Contraindications Contrast Technique Specific Conditions Complication References

Barium swallow is the contrast study from oral cavity upto the fundus of the stomach. INDICATIONS 1. Dysphagia and obstruction. 2. Pain during swallowing. 3. Assessment of mediastinal masses. 4. Assessment of left atrial enlargement. 5. Pre-op assessment of carcinoma bronchus and oesophagus. 6. Motility disorders of oesophagus, E.g.: Achalasia and diffuse oesophageal spasm, scleroderma. 7. Assessment of site of perforation. 8. Zenker's diverticulum and cricoid webs. In these cases water soluble contrast media are used. E.g. : Gastrograffin or dionosil aqueous. RELATIVE CONTRAINDICATIONS • Tracheo oesophageal fistula. • Perforation. CONTRAST • 100% Barium sulphate paste. • 80% Barium sulphate suspension.

60

Barium Swallow • 61

• 30% Barium sulphate suspension for high kV technique. • 200-250% high density, low viscosity for double contrast study. TECHNIQUE Pharynx One mouthful (about 10-15 ml) of contrast media (Barium sulphate paste) is given and fluoroscopic observation of the act of deglutition is observed in frontal and lateral view with the patient erect. To get optimum distension of the pharynx, exposure is triggered at the time when the hyoid bone is at the highest point during swallowing. For this, a string is tied just above the level of the larynx. The rotor is kept running and patient is asked to swallow. Exposure is released when the larynx comes above the string. Lateral film is taken in erect and frontal film in supine position. To Get Optimum Mucosal Coating One mouthful of contrast media (Barium sulphate paste) is given to the patient and the patient is instructed to swallow once and stop swallowing there after. Spot films are taken in frontal and lateral projections (better way is to ask patient to keep mouth open or say eee .... eee .... after one swallow) or patient performs valsalva maneuver in erect position with nose closed. Frontal and lateral spots are taken to show distended pyriform sinuses and valecullae. Oesophagus Single Contrast Multiple mouthfuls of 80% w /v Barium suspension are given. Follow the barium bolus down the oesophagus and observe the peristalsis always in supine position. Films are exposed in erect position­ RAO, LAO, frontal and lateral views when the oesophagus is well distended. In RAO position esophagus is projected clear of the spine. The escape of contrast at the level of the diaphragmatic hiatus should not be confused for reflux. Mucosal film is taken in RAO after the oesophagus is empty. Then the fundus of the stomach, & G-0 junction are assessed with spot films in different obliquities in erect and recumbent positions. Double Contrast Barium contrast should be high density, low viscosity (200 to 250%). 15-20 ml Barium is given in the mouth and the patient is asked to swallow. Then effervescent powder is given with another mouthful of barium. In erect position, gas tends to stay up, resulting in adequate

62 • Radiological Procedures

distension which stays for longer time as compared to supine position. Prone position also retains more gas within the oesophagus and gives adequate distension. Hypotonia using Buscopan or Glucagon keeps the esophagus distended for a longer time (Inj. Buscopan 2ml LV. given just before the procedure). Filming is done in frontal, lateral, RAO and LAO. Introduction of gas for double contrast studies can also be done through a tube passed into the upper oesophagus.

SPECIFIC CONDITIONS

1. Severe dysphagia for both solids and liquids: A little dilute Barium is given initially-5ml. Further filming and contrast depends on the abnormality observed. 2. Pharyngeal Web: Video fluorography in frontal and lateral projection is the best technique for investigating disorders of swallowing. 50/50 dilution of standard high density barium will show webs more readily. Films in supine for frontal, and erect for lateral views are taken at maximum distension of the pharynx. 3. Foreign body impaction: To detect the level of obstruction in case of radio-lucent foreign body in the oesophagus, a marsh mallow coated with barium is swallowed whole. The passage of marsh mallow will be hindered at the level of obstruction. Similarly, cotton soaked with barium can be swallowed, but advantage of the marsh mallow is that it dissolves spontaneously. 4. In Carcinoma: High viscosity, normal density liquid barium is given. 5. Motility disorders: A minimum of 5 mouthfuls of contrast should be given to study the motility disorders of the oesophagus, out of which more than 2 mouthfuls should be abnormal for a positive diagnosis. For motility disorders, a prone swallow is essential to assess oesophageal contraction in the absence of gravity. Disorders are either of peristalsis or sphincter abnormalities (lower and upper oesophageal sphincters). 6. Achalasia: The oesophagus should be cleansed thoroughly (aspirate and wash) so that secondary achlasia due to Ca oesophagus may not be missed. Barium 80% w/v is used and the patient should be studied in erect position. To differentiate achalasia from other conditions showing abnormal peris-talsis, mecholyl test is done. On administration of mecholyl, there will be hyperperistalsis, pain and streaks of contrast entering the stomach confirming the diagnosis of achalasia.

Barium Swallow • 63

Or Amyl Nitrate given orally will cause mild relaxation of the narrowed portion of the oesophagus, thus causing small streaks of contrast to enter the stomach. 7. Tracheo Oesophageal fistula • Congenital • Acquired Ideal contrast is non-ionic water soluble contrast media. When barium is used it should be fluid-like and patient should be lying lateral. Do not forget to put the patient prone if a fistula is not identifiable in the lateral position. If the fistula is seen, stop the procedure, since barium aspiration may result in inflammation and granuloma formation in the lung. To demonstrate Tracheo-oesophagal fistula in infants, a Ryle's tube is introduced to the level of mid oesophagus and contrast is injected while withdrawing the tube slowl y. This will force the contrast through any small fistula. Both lateral and prone views to be assessed. 8. Hiatus hernia: High abdominal pressure is required to demonstrate hiatus hernia. For this • Patient has to strain. • Patient is asked to lie down, straighten the legs and then raise them up. • Manual compression of the abdomen. • Patient stands upright, ask him to bend downwards with legs straight. Stomach should be well distended, otherwise the hiatus hernia may not be demonstrated. 9. Gastro oesophageal reflux: Siphon test. Fill the stomach with 50% Barium (150-200 ml). Follow this with 1-2 mouthfuls of water to remove traces of barium in the oesophagus. Make the patient supine with left side raised 15 ° up. Keep one mouthful of water in the patients mouth. Ask the patient to swallow the water-a jet of barium will shoot into the water column as it enters the G.O. junction. Alternatively with full stomach, ask the patient to roll from side to side on the table. Reflux will be seen. To promote reflux, abdominal pressure can be raised by straight leg raising or putting patient prone with the bolster under the abdomen at the level of the umbilicus, but these are unphysiological.

64 • Radiological Procedures

10. Oesophageal Varices : Supine right side up position, high density thin barium should be used. Varices are best demonstrated in mucosa! relief study after using Buscopan and valsalva maneuver. COMPLICATION 1. Leakage of barium from an unsuspected perforation-granuloma formation. 2. Aspiration. Present status of Ba. Swallow in comparison with the following: Oesophageal Endoscopy • It is a gold standard for diagnosis of oesophagitis, Barret's oesophagus & varices. • It is also useful to take biopsy for confirmation. Ultrasound • At present, endoscopic ultrasound provides the most accurate estimation of the depth of penetration in malignancy, the length of esophagus affected, and the extent of lymph node involvement in a patient of ca. esophagus. • Fine needle aspiration of suspicious lymph nodes can also be taken. • It is also useful in a patient of esophageal tear. Computed Tomography • Computed tomography is the standard tool for regional and distant staging of esophageal cancer. • It may detect thickened esophagus, enlarged lymph nodes, and involvement of the mediastinum, lung or liver.

Long Answer Questions---------------1. Discuss barium swallow under the following headings (a) Indications (b) Contraindications (c) Choice of contrast (d) Technique (e) Complications

Barium Swallow • 65

2. Discuss barium swallow examination in following conditions (a) Dysphagia for both solids and liquids (b) Pharyngeal web (c) Foreign body impaction (d) Carcinoma oesophagus (e) Oesophageal varices (f)Hiatus hernia

Short Answer Questions------------- - � 1. Enumerate in brief Siphon test carried out to demonstrate gastro­ oesophageal reflux. 2. How will you carry out barium swallow examination in cases of trachea-esophageal fistula ? 3. How will you perform barium swallow examination to demonstrate motility disorders of oesophagus. How will you differentiate Achalasia cardia from other motility disorders of oesophagus.

REFERENCES 1. Cunningham TE Jr., Joner G. Normal anatomy and techniques of examination of the pharynx. In : Freeny PC, Stevenson GW (eds). Marguilis and Burhenne's Alimentary Tract Radiology, 5th edn. St. Louis : Mosby, 1994 : 101-106. 2. Freeny PC, Stevenson GW (eds). Marguilis and Burhenne's Alimentary Tract Radiology, 5th edn. St. Louis : Mosby, 1994 : 176-184. 3. Freeman AH. Oesophagus. In : Graham H Whitehouse (ed). Techniques in diagnostic imaging, 3rd edn. Oxford : Blackwell Science, 1996 : 13-20.

Chapter 7

Barium Meal • • • • • • • • • • • •

Indications Contraindications Preparation Contrast Media Standard Views Conventional Single Contrast Study Double Contrast Barium Study Biphasic Study Of Upper Git Hypotonic Duodenography After Care Complications References

Barium meal is the radiological study of oesophagus, stomach, duodenum and proximal jejunum. It is done by oral administration of c ontrast media (Barium sulphate). INDICATIONS 1. Symptoms which prompts Barium meal study are : (a) Epigastric pain suggestive of peptic ulceration. (b) Anorexia. (c) Weight loss. (d) Vomiting. (e) Anaemia. (f) H eart burn. (g) Dyspepsia. 2. Upper abdominal mass. 3. Castro-intestinal haemorrhage. 4. Gastric or duodenal obstruction.

66

Barium Meal • 67

5. Malignancies of oesophago-gastric junction, stomach and duodenum. 6. Systemic diseases like Tuberculosis affecting the upper gastro­ intestinal tract. 7. Motility disorders of gastro-intestinal tract. 8. In children to identify a cause for vomiting due to : (i) Castro­ oesophageal reflux; (ii) Pyloric obstruction; (iii) Malrotation.

CONTRAINDICATIONS • Suspected cases of gastro-duodenal perforation • History or suspicion of aspiration, where alternative contrast medium should be considered. • Large bowel obstruction (Barium inspissation occurs in these cases) • Fistulous communication with any organs other than parts of G.I.T. • Recent biopsy from GIT, as barium granuloma may form at biopsy site. PREPARATION • Patient should not eat or drink for atleast 6 hours before examination. Patients who are undergoing a routine study during a morning session are usually told to fast overnight. • As cigarette smoking may interfere with optimum coating of the mucosa, patients should restrain from smoking. • As prolonged fasting is harmful for patients with diabetes, early morning appointment should be arranged. • In patients with gastric outlet obstruction, prolonged fasting or intravenous Metacloprarnide and sometimes nasogastric intubation and aspiration of the contents may be necessary. CONTRAST MEDIA Single Contrast Study Low density barium suspension (80-100% w /v) is used. 30% w /v suspension is used for high kV single contrast study. Water soluble contrast media are indicated when a gastro-duodenal perforation is suspected. Use of newer non-ionic water soluble contrast media have to advocated for the detection of upper GI perforation, when there is risk of aspiration.

68 • Radiological Procedures

Double Contrast Study A high density (approximately 250% w/v), low viscosity barium suspension produces best mucosal coating and hence detail. Between 100 and 150 ml of barium suspension is usually necessary to achieve adequate double contrast studies.

STANDARD VIEWS Fundus

Single Contrast (SC) Supine

Body

Erect or Prone

Antrum and Prone right side down Pylorus Prone right side down D1 and C loop of duodenum D4 of duodenum Supine

Double Contrast (DC) Erect with two views 90° to each other or Prone right side down Supine with 60° head end elevation Supine right side up Supine right side up Prone right side down

CONVENTIONAL SINGLE CONTRAST STUDY In conventional study, radiography is done at 80-90 kV. In erect position, fluoroscopy is done to visualise both domes of the diaphragm and lung bases to detect any pathology. The stomach and intestines are seen for fluid levels. 10-15 ml of 80-100% w/v barium suspension is given and patient is made to swallow while esophagus is seen under fluoroscopy. The table is made horizontal, and the patient lying supine is rotated with the right side going up. In this way the patient is rotated in a continuous clockwise manner as seen from the foot end of the patient. A good coating of the entire stomach mucosa is thus obtained and radiography is done to show the mucosal relief. If the coating is inadequate, the patient is rolled again in the same direction before taking the film. The patient is kept supine and about 100-250 ml of barium is given. Spot films of the filled fundus in varying obliquity may be taken if any abnormality is detected. With the table horizontal, patient is turned prone oblique right side dependent. In this position, barium enters the duodenum through the pylorus. Spot films for duodenal

Barium Meal • 69

bulb and C loop can be taken after adjusting the obliquity to avoid overlap. Spot films should be taken, both in distended and empty states. Patient is then turned supine and the table is made erect. The spot films for duodenal bulb and C loop are taken in right anterior oblique position. Compression spot films of duodenum may be taken if required. More barium is given to distend the stomach wall. Standard filming of esophagus may be done now while giving the barium. Graded compression is given to see the mucosa! folds, and spot films may be taken if required. The gastric peristalsis and rate of emptying through the pylorus is observed. The patient is rotated under fluoroscopy to observe all margins of the stomach so that anteriorly or posteriorly placed lesions are not missed. In erect position, right anterior oblique view of stomach shows incisura angularis. Proximal jejunum is also seen well in this view. To evaluate the retrogastric space, about 200-250 ml of barium is given. In supine position, translateral film is taken to demonstrate the retrogastric space. The disadvantage of the conventional single contrast study is that small mucosa! lesions like polyps or early carcinoma may not be demonstrated. This can be partly overcome by a single high kV technique.

Single Contrast High kV Technique Barium sulphate 30% w /v is used. Radiography is done at 120-130 kV. This permits visualisation through the barium column so that lesions will not be drowned by the low density barium. Adequate mucosa! relief study is not possible with such low density barium. Remaining aspects of barium meal are similar to conventional single contrast study. Advantages of single contrast studies • It is optimal for patients who are immobile or unable to swallow gas forming tablets. • Pylorospasm, fistulae and enlarged gastric rugae are best seen. • Filling defects due to large masses in pyloric and duodenal region are more easily identifiable by single contrast study. These are less obviously identifiable on double contrast. • It is the procedure of choice to examine patients with suspected gastric or duodenal obstruction.

70 • Radiological Procedures

Disadvantages of single contrast study • Lack of sensitivity in detecting small erosion/linear ulceration, superficial gastric carcinomas and subtle mucosal abnormalities.

DOUBLE CONTRAST BARIUM STUDY This technique was perfected in Japan where there is a high incidence of gastric malignancy. Main purpose was for mass screening of the gastric tumours for early detection. This technique relies much less on fluoroscopy and more on filming which is done overcouch for better image quality. This was subsequently found very useful for small mucosal lesions like polyps, mucosal erosions and ulcers, recurrent tumours and post operative studies. Preparation A 'dry' fluid free stomach is essential. Double contrast study should not be done if secretions exist in the stomach. The secretions will prevent adequate mucosal coating and may mimic tumours. Contrast Media High density (200-250% w/v) low viscosity barium sulphate is essential. High viscosity barium does not flow well and does not coat mucosa well, hence can produce apparent mucosal lesions. Antifoaming agents which are added to barium suspension prevent air bubble formation. Air bubbles can mimic polyps. Gas Forming Agents To produce gas in the stomach, Sodium bicarbonate and Citric acid are given orally. When they come in contact in the stomach, carbon dioxide is produced which acts as negative contrast. Commercially available powders like gastrovision, eno, fruit salt etc. give good and rapid gas release for double contrast studies. When Ryle' s tube is placed in the stomach, this can be used to inject air. Smooth Muscle Relaxants Hyoscine (as n-butyl bromide, trade name : Buscopan) when given intravenously produces good distension of the stomach and bowel by smooth muscle relaxation and produces effacement of the mucosal folds. Dosage of Buscopan is 1 ml (20 mg) through intravenous route.

Barium Meal • 71

LV. Buscopan is contraindicated in patients with : • Glaucoma • Urinary retention • Tachycardia • Cardiac diseases • Poor general condition • Haemodynamic imbalance.

Technique of Double Contrast Injection Buscopan IV should be given just before giving barium to study the stomach. To study the stomach and duodenum, injection Buscopan is given when barium enters the duodenum. About 100-150 ml of high density low viscosity barium is given. Injection Buscopan is given as described before. Gas forming agents are given. Then patient is rotated slowly for mucosal coating, beginning from supine to right lateral to prone to left lateral and back to supine. Filming for various parts of stomach and duodenum is done with standard views as stated before. The table may have to be tilted 30 ° headup /head low to attain maximum distension of the part to be filmed. The study can be done without buscopan, rest of the procedure remains the same. Advantages of double contrast study • Highly accurate method of detecting abnormalities following gastric surgery, bile reflux gastritis, marginal ulceration, recurrent carcinomas and abnormalities of the efferent loop. Disadvantages of double contrast study • Probably misses some polyps, ulcers, erosions, superficial carcinoma. • Biphasic study overcomes all these problems and is the best and most accurate method of evaluation of upper GIT. If meticulously performed, it gives very good anatomic, as well as physiologic information and has an accuracy which is comparable to endoscopy. BIPHASIC STUDY OF UPPER GIT Introduction • Gives good anatomic & physiologic information & has accuracy comparable to endoscopy.

72 • Radiological Procedures

Goal • To have both mucosal delineation in double contrast phase & full column distention in single contrast phase. Contrast Medium • 60-100% low viscosity, 200-250 ml of Barium is given orally with gas forming powder in the last few mouthfuls. Filming • Duodenal spot filming is done first to (a) Prone oblique Rt.side down (b) Supine with Rt. side up oblique : (c) Erect (d) Supine with 60° head up (e) Supine

avoid flooding of the bowel Duodenal cap, C-loop Duodenum Gastric fundus Upper body of Stomach Lower body of Stomach, Pyloric antrum (f) Supine with Rt. side up oblique : Pyloric antrum & Canal. Note: Biphasic examination has to be performed quickly, without wasting time. More gas and barium may be given as required.

HYPOTONIC DUODENOGRAPHY Tubeless hypotonic duodenography can be performed as part of routine double contrast barium meal or as a specific examination of the duodenum. Rarely, persistent pylorospasm, poor coating, poor distension or an unusual position of the duodenal loop can lead to failure. With I.V. line fixed, about 100 ml of high density low viscosity barium is administered by mouth. The patient is turned prone with right side down position. As soon as the fully distended duodenal cap is seen, Buscopan is injected I.V. Gas producing powder is then given after turning the patient supine with right side up position. First and second part of duodenum is seen now in double contrast and the barium enters the third and fourth part. Filming is done same as in double contrast barium meal to demonstrate various parts of the duodenum. Tube Method: The Bilbao-Dotter tube is passed into the first part of the duodenum. I.V. line is fixed. With the patient in supine position,

Barium Meal • 73

50 ml of barium is injected through the tube and injection Buscopan is given I.V. The patient is turned so that the right side is up and air is injected through the tube. Films are taken in RAO position (first and second part of duodenum). Then the patient is turned prone and more air is injected till air reaches the third part and a film is taken. Then the patient is turned left side down lateral and a film for double contrast of second part of duodenum is taken. Patient is then turned supine and a film is taken for overview of duodenum on a large film.

Advantages of hypotonic duodenography • Reliable results are obtained. • Duodenal lumen is separable easily • There is no overlap of stomach

Disadvantages of hypotonic duodenography • Pylorus is not assessed • Uncomfortable to patient • Amount of barium entering cannot be controlled.

AFTER CARE • The patient should be warned that his bowel motion will be white for few days after the examination and to keep his bowel open with laxative to avoid barium impaction which can be painful. • The patient must not leave the department until any blurring of vision produced by Buscopan has resolved. COMPLICATIONS 1. Leakage of barium from an unsuspected perforation-peritonitis. 2. Aspiration pneumonia. 3. Barium impaction-converts a partial large bowel obstruction into a complete obstruction. 4. Side effects from the pharmacological agents used alongwith barium. 5. Acute gastric dilatation. 6. Barium embolisation if a bleeding ulcer is present.

74 • Radiological Procedures

Comparison of barium studies with other modalities like

�-�

Endoscopy Barium Meal 1. Procedure of choice as diagnostic It has low diagnostic accuracy accuracy is very high (Around (Around 83 %). Hence it is done when endoscopy is 100%) contraindicated. i Ideal for erosive ulcers, smai 1 Ideal when endoscopy is recurrent ulcers & early detection I contraindicated (in severe acute of tumour & biopsy can also be cardiac or pulmonary diseases.) I taken from the lesion. It is the modality to study the physiology i.e. peristalsis & emptying time.

2.1

Endoscopic Ultrasound 1. It is,..ideal to assess the extent of growth & its extension into the wall of oesophagus. 2. It is useful in early detection of lymph nodes. 3. Biopsy can also be taken for confirmation of diagnosis. Computed Tomography 1. Main role of C.T. is in staging the malignant disease process. 2. It is the modality of choice to assess the structure outside stomach wall.

Long Answer Questions----------------1. Discuss barium meal examination under the following heading (a) Contrast media (b) Indications (c) Contraindications (d) Preparation of patient (e) Radiographic positioning (f) Complications and after care 2. Describe the contrast media used in barium meal study . Describe the technique, advantage and disadvantage of (a) Single contrast barium meal study (b) Double contrast barium meal study

Barium Meal • 75

Short Answer Questions ---

-

-- - - - - - - --

1. Mention the indications and contraindications of barium meal study. 2. Mention the variations in barium preparation used for (a) Single contrast study (b) Double contrast study (c) Biphasic study 3. Mention the indications and contraindications of Single contrast study. 4. Mention the contraindications of Double contrast study. 5. Discuss the complications of barium meal study. 6. Briefly describe the biphasic study of upper gastrointestinal tract. 7. Describe briefly Hypotonic duodenography. 8. What are the advantages and disadvantages of barium meal study as compared to endoscopy ? 9. What is the role of computer tomography in stomach lesions ?

REFERENCES

l. Harrie KM, Robert GM, Laurie BW. Normal anatomy and techniques of examination of stomach and duodenum. In : Freeny PC, Stevenson GW (edn). Marguilis and Burhenne's Alimentary Tract Radiology, 5th edn. St. Louis : Mosby, 1994 : 286-296. 2. Nolan DJ. Stomach and duodenum. In: Graham H Whitehouse (ed). Techniques in diagnostic imaging, 3rd edn. Oxford : Blackwell Science, 1996 : 22-33.

Chapter 8

Barium Meal Follow Through • • • • • • • • • • • • •

Indications Contraindications Contrast Medium Preparation Small Bowel Follow Through Dedicated Small Bowel Follow Through Peroral Pneumocolon Retrograde Small Bowel Examination Advantages of BMFT Disadvantages of BMFT Complications Interpretation References

Bari um studies are still the mainstay for evaluating patients with suspected small bowel abnormalities. The major methods used for the barium examination of the small bowel are: 1. Small bowel follow through examination. 2. Dedicated small bowel follow through examination. 3. Enteroclysis (or) small bowel enema. 4. Peroral pneumocolon. 5. Retrograde small bowel examination. It is the radiographic examination of the GIT-oesophagus, stomach, duodenum, small bowel and ileocaecal junction by oral administration of contrast media. It is so called because it is performed followin g a barium meal examination of the oesophagus, stomach and duodenum.

76

Barium Meal Follow Through • 77

INDICATIONS 1. Patients who have low suspzcwn of small bowel disease -

abdominal pain and diarrhoea. 2. Patients with suspected complete (or) near complete small bowel obstruction. 3. Patients who are suspected of suffering from Crohn's disease. 4. Patients who refuse placement of nasogastric tube/failed intubation. If enteroclysis is the routine method, the barium follow through will only be used for 1. Elderly patients with suspected jejunal diverticulosis who present with malabsorption. 2. In patients who are unwilling or in whom it is not possible to perform intubation.

CONTRAINDICATIONS 1. Colonic obstruction. 2. Suspected perforation. 3. Paralytic Ileus.

CONTRAST MEDIUM

Medium density barium suspension (50-60% w/v) contalIUilg a suspending agent (to maintain its stability and prevent flocculation) is used. High density barium (200-250% w/v) may produce an appearance of fold thickening and clumping in the small bowel. Acid barium sulphate suspension produces spasm, enlarged folds and dilatation in duodenum and jejunum. Alkaline barium sulphate suspension may improve coating of the valvulae conniventes which increases diagnostic accuracy. A water soluble Iodine contrast agent such as gastrograffin is of limited value as it will be diluted and lose density in the small bowel. If they are used in cases of small intestinal obstruction, they may be so diluted by bowel content and their own osmotic action that they would fail to demonstrate either the site or the cause of the obstruction. In the old and frail patient or in young infants, there is additional hazard that their osmotic action can seriously diminish blood volume. It is safe to use barium if small bowel obstruction is suspected and colonic obstruction is ruled out, to find the cause and site of the lesion. Therefore, the principal value of water soluble media is in the demonstration of leaks from the bowel.

78 • Radiological Procedures

PREPARATION Before any small intestinal study 1. The colon should be cleaned by the administration of a suitable purgative. (Purgative should be avoided in patients with suspected obstruction, acute exacerbation of Crohn's disease or an Ileostomy). 2. A low roughage diet and a high fluid intake is also maintained for 48 hours prior to the investigation 3. No food or fluid should be taken for 12 hours before the investigation. If the patient is taking tranquilizers, antispasmodics and codeine, they should be stopped for 24-48 hours before the examination.

SMALL BOWEL FOLLOW THROUGH Initially 150 ml of high density barium and effervescent agents are used to evaluate oesophagus, stomach and duodenum by means of double contrast examination. Later 200 ml of barium (20-25%) (to decrease the high density effect from double contrast study of Upper GI study) followed by 250 ml of barium (40-45%) is given. Once this is completed, a series of overhead radiographs are obtained at half­ hourly intervals till terminal ileum is reached.

DEDICATED SMALL BOWEL FOLLOW THROUGH • Single contrast technique. • Double contrast technique. Single Contrast Technique Single contrast technique is employed routinely in our department. Barium (600-900 ml) 50-60% is administered. Patient is asked to drink this as rapidly as possible. He is then put in the right side dependent position to aid rapid gastric emptying. After 15 to 20 minutes, a film is taken with the patient prone to separate the bowel loops, using high kV to demonstrate jejunum and proximal ileum. Subsequent films are taken at 15-30 minute intervals till ileocaecal junction is opacified. To demonstrate ileocaecal junction, supine right side up is the best position since ileum enters caecum in the posteromedial part. Advantages of Prone Position • Better separation & less overlap of bowel loops.

Barium Meal Follow Through • 79

• In this position the center of the abdomen is compressed making entire abdomen more uniform and thus more uniform x-ray penetration can be achieved. • In this position loops of ileum tends to migrate cephalad and becomes less compacted in the pelvis which is often a common problem during procedure. First Second Third ---

�

Positioning Right side down dependent Prone Right side up

Purpose To aid gastric emptying I To separate bowel --� loops To visualise IC junction

• Always empty the bladder prior to these spot films. • Each overhead radiograph should be examined as soon as it is processed. Any suspected abnormalities should be evaluated with fluoroscopy and compression spot films. • Many authorities recommend, that even in the absence of any abnormality, periodic fluoroscopic examination and compression spot images have to be taken. Four spots of the ileo caecal junction should be taken with varying degrees of compression. Compression should be applied on the bowel loops to avoid overlap and to efface the mucosa so that the small lesions may not be missed and mobility of the loops can be well assessed. Spot films should be taken if required. The abnormalities must be shown atleast in two spot films taken at different times to demonstrate the persistence of the lesion. Overlap of contrast filled bowel loops in the pelvis is often a problem.

* Overlap of Contrast Filled Bowel Loops in the Pelvis Can Beovercome by: • Table head down. • 30 ° caudal angled view of pelvis. • Emptying of urinary bladder prior to filming the ileal loops.

* If Desired, Gastric and Bowel Peristalsis may be Increased by various methods 1. Drugs Metaclopramide, Neostigmine, Glucagon, Cholecystokinin. Of these, metaclopramide is most frequently used. This promotes bowel motility and can decrease the transit time of barium.

80 • Radiological Procedures

Metaclopromide hydrochloride is available as: • Injection Perinorm or Injection Maxeron 5 mg/ml-2ml Ampoule. Dose: 2ml Injection given I.M 10-15 minutes after giving Barium suspension following stomach, duodenal study. • Tab. Perinorm or Maxeron-10 mg tabs. Dose: 2 tabs given with the barium after stomach, duodenal study. Caution : In some patients it may lead to drowsiness (or) a Parkinsonian like state. (Extra pyramidal reactions.) 2. 20-40 ml of sodium/meglumine diatrizoate to the barium also reduces transit time. 3. Use of cold water to dilute barium and intermittent ice cold water sips. • Cooling makes the barium more palatable. • More importantly cold barium speeds the gastric emptying and passes more rapidly through the intestine than does the room-temperature barium. 4. Preliminary cleansing of the colon and placing the patient in right lateral recumbent position. Note: l. Polyposis: Films taken with collapsed loops show the polyps to best advantage. 2. Diverticulosis: Delayed films may show persistence of barium in the diverticulae. Erect position will reveal any fluid levels caused by contrast media retained within the diverticulae. 3. Large ulcers: Large collection of barium may be seen in the delayed film after the bowel loops have emptied the barium. 4. The transit time through the small bowel can vary greatly ranging between 15 minutes and 5 hours PERORAL PNEUMOCOLON It is done at the end of B.M.F.T. when terminal ileum is suspicious and needs clarification. It is used mainly to evaluate distal ileum. Preparation Colonic preparation is similar to barium enema.

Barium Meal Follow Through • 81

Technique • Barium is administered orally. • When barium has reached the right and proximal transverse colon, air is insufflated into the rectum and refluxed into distal ileum. • Glucagon can be used to relax the ileocaecal valve. • It is usually employed at the end of barium meal follow through, when the appearance of terminal ileum is suspicious and needs clarification. Advantages • A routine overhead radiograph following use of the pneumocolon technique for SBM examination can yield unsuspected & clinically significant colonic findings. RETROGRADE SMALL BOWEL EXAMINATION Barium and air refluxed through the ileocaecal valve during a barium enema examination may be used to examine the small bowel. This is replaced nowadays by enteroclysis.

Advantages of BMFT 1. Easily performed. 2. No discomfort/intubation to the patient unlike in enteroclysis. 3. It is a physiological process. Hence transit time can be assessed. Disadvantages of BMFT 1. Overlapping of barium filled bowel loops in the pelvis. 2. Poor distension of bowel loops. 3. Inappropriate timing for visualization of partial (or) intermittent small bowel obstruction. 4. Operator dependence. 5. Time consuming. COMPLICATIONS 1. Leakage of barium from an unsuspected perforation. 2. Aspiration. 3. Conversion of partial large bowel obstruction into a complete obstruction by the impaction of barium. 4. Barium appendicitis, if barium impacts in the appendix. 5. Side effects of pharmacological agents used.

82 • Radiological Procedures

What to do in suspected cases of perforation? Water soluble contrast media are indicated when perforation is suspected. Using a Ryles tube, aspirate the stomach contents and then give about 100 ml of water soluble contrast media (76% w /v) through the Ryle's tube. Tilt the patient's head up to promote emptying and look for evidence of leak through stomach or duodenum. If the patient is erect, the contrast media may be seen to collect in the pelvis if perforation is present. If patient is supine, contrast leak through anterior wall perforation may not be identifiable. If no leak is identifiable, opacification of the urinary bladder or kidneys is an indirect evidence of a perforation because contrast media is not absorbed from the GIT. The contrast media in the above case is absorbed from the peritoneum and is excreted by the kidneys.

INTERPRETATION Small intestine extends from duodenojejunal flexure (ligament of treitz) to the ileocaecal valve. • Length - 6-7 metres. • Calibre gradually diminishes. Anatomical Differences Between Jejunum and Ileum 1.

2. 3. 4. 5. 6.

Jejunum Proximal 2/5th of small intestine (100-110 cm) Thicker and more vascular wall Wider and often empty lumen

Ileum Distal 3/5 of small intestine (150-160 cm) Thinner and less vascular wall Narrower and often loaded lumen Larger and closely set circular Smaller and few circular folds folds Villi are larger in number Very few villi Peyer's patches are absent Peyer's patches are present. th

Appearance of Jejunum and Ileum On Barium Study Jejunum Ileum Upper left & periumbilical region Lower right hypogastric pelvic region Feathery appearance Featureless

and

Barium Meal Follow Through • 83

Ileum

Jejunum Constitutes proximal two-fifths of small intestine

Three-fifths

Position

Upper left and periumblical region

Lower right hypogastric and pelvic region

Max. Diameter

4 cm

3cm

Number of folds 4-7 per cm

3-5 per cm

• Fold thickness 1.5-2 mm. • Measurement of approximated bowel wall gives a wall depth of 1-1.5 mm. • The collapsed bowel shows a feathery mucosal pattern in the jejunum on BMFT due to valvulae conniventes. • The pattern in ileum is less feathery and may be absent.

Long Answer Questions ---------- - - - - -1. Discuss barium meal follow through under following headings: (a) Definition (b) Indications (c) Contraindications (d) Contrast medium used in barium meal follow through (e) Preparation of patient (f) Describe the procedure & filming done in dedicated small bowel follow through (g) Advantages & disadvantages of barium meal follow through (h) Complications of barium meal follow through

Short Answer Questions ------

- - - - -----

1. Discuss the difference between the jejunum & ileum anatomically and on barium study. 2. What are the indications & contraindications of barium meal follow through. 3. Discuss the contrast medium used in barium meal follow through. 4. What are the advantages of prone position during filming in barium meal follow through study? 5. What are the various methods used to increase gastric and bowel peristalsis during barium meal follow through study?

84 • Radiological Procedures

6. What is the role of cold water barium during barium meal follow through study? 7. Describe briefly Peroral pneumocolon. 8. How do you diagnose perforation by barium study? 9. Shortly describe capsule endoscopy.

REFERENCES 1. Freeny PC, Stevenson GW (eds). Marguilis and Burhenne's Alimentary Tract Radiology, 5th edn. St. Louis : Mosby, 1994 : 514-525. 2. S. Chou, S,J. Skehan, A.L. Brown, J. Rawlinson, S. Somevs. Detection of unsuspected colonic abnormality using the pneumocolon technique during small bowel meal examination Clinical Radiology, June 2000, Vol. 55 No. 6 : 454-458.

Chapter 9

Enteroclysis (Small Bowel Enema) • • • • • • • • • • • • • • • • •

Indications Contraindications Equipment Contrast Medium Preparation Technique Single Contrast Enteroclysis Double Contrast Enteroclysis Air Double Contrast Enteroclysis Comparison Advantages Disadvantages After Care Complications CT Enteroclysis MR Enteroclysis Refer ences

T his is the radiological study of small bowel from jejunum to the ileocaecal junction by intubation of the jejunum and instillation of contrast through the tub e. INDICATIONS 1. Partial small bowel obstruction. 2. Cro hn' s disease-to know its extent. 3. Suspected M eckel' s div erticulum. 4. Malabsorption. 5. Tumor s of small intestine. 6. Occult GIT bleeding. 7. Equivocal BMFT but strong clinical suspicion. 85

86 • Radiological Procedures

CONTRAINDICATIONS 1. 2. 3. 4.

Complete colonic obstruction. Suspected perforation. Massive dilatation of the small bowel. Duodenal obstruction and gastrojejunostomy. 5. Paralytic ileus.

EQUIPMENT Bilbao Dotter tube: This is a 22F polyethylene tube which is 150 cm long. The tube is 5 cm longer than the guide wire in order to eliminate the risk of perforation by the wire protruding beyond the tip. The tip has multiple side holes with or without an end hole. Usually there are 8 holes. The guide wire is teflon coated to reduce friction.

CONTRAST MEDIUM The contrast medium used for small bowel study is Barium sulphate. This contrast medium should not flocculate, precipitate or settle down in the presence of intestinal secretions. The above characteristics can be accomplished by micro pulverisation of barium and addition of a suspending agent. An acid Barium sulphate suspension can produce spasm, enlarged folds, dilatation in the duodenum and jejunum and also hypersecretion, hence this should not be used. On the other hand, an alkaline Barium suspension improves the coating of valvulae conniventes and hence should be used. 1. For single contrast enteroclysis: 20% w /v suspension of Barium sulphate is used. 2. For double contrast enteroclysis: high density low viscosity Barium sulphate suspension is ideal which is 200-250% w /v. We can use 95% Microbar which can be diluted to 70% to decrease the viscosity. Another important constituent is carboxy-Methyl­ cellulose (CMC). To prepare this, add 10 gm of C.M.C. to 2 litres of warm water and mix well. Then refrigerate the mixture overnight. Shake this mixture well before use.

PREPARATION 1. The patient is subjected to liquid diet (2-3 litres) for a full day before the examination and is called after overnight fasting for the procedure.

Enteroclysis (Small Bowel Enema) • 87

2. Two to four Dulcolax tablets in the evening preceding the enteroclysis are given. The above said preparation is very important because a full caecum or a food filled ileum seriously retards intestinal flow and produces artifacts and more fluid is needed to reach the caecum quickly. 3. No rectal enema should be given because the enema fluid may reflux into the small bowel and create confusing small bowel patterns when it mixes with the Barium suspension. 4. Drugs such as Tranquilisers, Sedatives and Antispasmodics should be discontinued the day before the examination. Anticholinergics and Ganglion blocking drugs tend to cause dilatation of the small bowel mimicking the sprue pattern. Narcotics affect both the motility and appearance of folds of the small bowel. 5. Immediately before the examination, the pharynx is anaesthetised with lignocaine jelly. For Infant 1. 4 hours fasting. 2. To enhance gastric emptying, turn the baby to his right side. 3. Sedation. 4. Decreased peristalsis-compensated by 3-5 ml of metaclopromide. Contrast Dose Age

3-5 Months 5-8 Months 8-11 Months 1-3 Years

I

Dose

200 300 400 500

ml ml ml ml

TECHNIQUE Preliminary Plain Radiographs of the Abdomen • They are useful to determine whether the patient is adequately prepared and to exclude the presence of barium from previous examinations. They also help in deciding the best radiographic method for evaluating a patient with suspected small bowel disease. For example, a patient with distension of only the proximal small bowel loops would be best examined with enteroclysis whereas a patient with distension of the entire small bowel would benefit from barium enema.

88 • Radiological Procedures

• An upright film is useful to determine whether a large amount of fluid is present in the stomach or small bowel loops, which needs to be aspirated before the study can be performed. • Free intraperitoneal air, displacement of bowel loops by a mass, calcification and abnormality of bowel loops other than distension can be observed in the preliminary film. Procedure The patient sits upright on a chair placed against the wall so that he cannot move away from the advanced tube. Alternatively, in a patient who cannot sit up, the tube can be placed with patient supine or right lateral on the fluoroscopy table. 2-3 cc of 2% Xylocaine jelly is introduced into the nostril through which the tube is to be placed after ensuring that there is no nasal block or mass. Patients' neck is hyper-extended. After this, the Bilbao-Dotter tube without the guide wire is inserted through one of the nostrils and advanced with the swallowing action of the patient till the tip reaches the stomach. About 5-7 cm of tube is passed in stomach and then neck is flexed. The guide wire may be used to stiffen the tube to assist advancement through the oesophagus into the stomach. Make sure the tube is in the oesophagus and not in the trachea by asking the patient to cough and by observing under fluoroscopy. After 2/3rd of the tube is passed, tip must be in the stomach. Under fluoroscopic control, the tube is then advanced through the antrum of the stomach into the pyloric canal. Now, with the guide wire 5 cm proximal to the tube tip, the tube is slowly advanced till the tip enters the duodenal cap. This may be facilitated by turning the patient supine with right side up so that the location of the pyloric canal and duodenal cap can be seen outlined by air. If this fails, turning the patient prone with right side down oblique may help the tube to reach pyloric canal by gravity. Once the tube tip enters the first part of the duodenum, advance the tube slowly keeping the guide wire 2-3 cm proximal to the Pyloric sphincter. Withdraw the guidewire after each advancement. At the end, the tube will be beyond duodeno-jejunal flexure and the guidewire in the pyloric canal. Finally, the tube tip should be approximately 4-5 cm distal to Trietz ligament. Such a placement prevents reflux of Barium and carboxymethyl cellulose into proximal parts of duodenum and stomach.

Enteroclysis (Small Bowel Enema) • 89

Note: 1. If the stomach is collapsed or has very little gas, injecting 100-150 ml of air will help the above manipulation. 2. If the stomach is over distended with gas, aspirate out air to reduce distension. 3. If stomach contains residual fluid, it should be sucked out prior to manipulation 4. While advancing the tube it will tend to hold up at the following places due to acute angulation of the intestine. • Junction of the first and second part of the duodenum. • Junction of the second and third part of the duodenum. • Duodeno jejunal fluxure. Gentle pressure on the tube assisted by deep breathing by the patient will help to negotiate these bends. Problems Prolonged Examination It is due to improper flow rates. Too high infusion rates should not be used. To restore peristalsis, injection metoclopramide 10 mg. I.V. is useful. Incomplete Distension of Small Bowel It is due to slow infusion rates, or due to excessive dose or response of metaclopramide. Increasing the rate of flow of contrast will solve the problem. Prolapse of Small Bowel into the Pelvis Few loops of ileum may dip into the pelvis. When no adhesions are present: angled compression allows lifting of pelvic segments. If cecum obscures the pelvic ileum, patient is turned prone and the table is tilted head down. This allows the caecum to empty and terminal ileum becomes visible. Faecal Material in the Terminal Ileum This may be seen due to an incompetent ileo caecal valve or in patients who are chronic users of laxatives or are taking long-term mild sedation. Infusion of an adequate amount of methylcellulose will push the debris into the colon.

90 • Radiological Procedures

Reflux into Duodenum and Stomach This is due to too fast infusion rate or small bowel obstruction. Incidence can be reduced by the use of balloon enterocly sis catheter. In patients with obstruction, preliminary decompression of the stomach and proximal jejunum decreases reflux. SINGLE CONTRAST ENTEROCLYSIS This is performed in a patient with high grade partial small bowel obstruction, especially if significantly dilated bowel loops are present. Barium suspension 20% w/v. is injected at the rate of 75 to 120 ml/ minute. Care should be taken to ensure that no air goes in during the injection. An average of one to one and half litres of barium sulfate is injected without any interruption. The average time taken to reach the ileo caecal junction is about 15 minutes. Use interrupted fluoroscopy to follow the head of the Barium column. Stenotic lesions are best identifiable at the head of the barium column. Filming: Take one 10 x 12 spot film for the jejunal loops. Another film is taken for the entire small bowel. Spot films are taken with or without compression wherever necessary. Spots of the ileo caecal junction are included with and without compression. All the filming is done with high kV technique (120-140 kV). DOUBLE CONTRAST ENTEROCLYSIS 150 to 500 ml of barium suspension (high density and low viscosity) is injected at the rate of 80-lO0ml/minute, till the proximal ileum is reached. The head of the barium column is followed with intermittent fluoroscopy and films are exposed wherever necessary. After this, 0.5% suspension of CMC is injected at a rate of around 75-120 ml/ min using a mechanical injector. Very rapid injection may result in atonia. Ileocaecal spot films should be taken initially when the barium column reaches the ileo caecal junction and then again when the ileo caecal junction is in double contrast. If the patient has an urge to defecate, he may be permitted to do so. The ileo caecal junction will be seen well with double contrast immediately after he defecates and spot films may be taken at this time. Filming: • Upper abdomen when jejunum is seen in double contrast.

Enteroclysis (Small Bowel Enema) • 91

• Full abdomen when entire small bowel is in double contrast. • Ileocaecal spots in single and double contrast. • Spot films as required.

Note: • Filming has to be completed within 20-25 minutes for good double contrast effect. • Erect films do not give any additional information of small bowel study. AIR DOUBLE CONTRAST ENTEROCLYSIS Preparation Laxatives are given the night before the examination. Nothing is to be taken by mouth after 7 pm the night before the examination.

Procedure Barium: A 50% to 70% w/v Barium sulphate. At a rate of approximately 60 ml/min, using a 100 ml syringe, 150 to 200 ml of barium suspension is injected slowly. The progress of the barium column is observed by interval fluoroscopy. When the head of the barium column reaches the distal ileum, air should be injected. Initially, 200 ml of air is injected slowly at a rate of approximately 100 ml/min. After observing the progression of barium distally, inject 100-200 ml of air. About 600 to 1000 ml of air is necessary for double contrast views of the whole small bowel. When the air reaches the distal ileum, an antispasmodic agent is injected intravenously or intramuscularly. Procedure 150-200 ml of Barium. (60 ml/min) j, When barium reaches distal ileum j, 600 - 1000 ml of AIK (100 ml/min) j, When AIR reaches distal ileum j, ANTISPASMODIC agent is given.

92 • Radiological Procedures

Advantages The mucosal detail seen on the air double contrast study of the small intestine is superior to any other examination. Aphthoid ulcer and minute scar can be picked up easily.

Disadvantages 1. Difficult to reproduce 2. Uncomfortable to the patient 3. Air may pass through the minimal narrowing and mild narrowing may be missed.

COMPARISON Methyl Cellulose DC Enteroclysis

1 2 3

Air DC Enteroclysis

Less information compared to air More clear detail Simple procedure, can be done by Operator dependent inexperienced radiologist More time Less time (20 minutes)

Advantages 1. Contrast material is administered at a desired rate and not influenced by the action of pyloric sphincter. 2. Direct infusion at a rate that produces hypotonia, completely dilates the entire small intestine and therefore the fold patterns and mucosal abnormality can be easily assesed. The frequent intermittent flucroscopic monitoring during the enteroclysis examination, together with the volume challenge induced by the infusion, facilitates the recognition of fixed & non distensible segments. 3. Because the distensibility of bowel lumen is challenged by enteroclysis, the bowel proximal to stenosis dilates-thus facilitating recognition of even a minimal narrowing. 4. Sinuses and fistulous tracts can be demonstrated by enteroclysis. 5. The time taken for the examination is not more than 20-30 minutes. 6. Enteroclysis tube may be left in place in patients with obstruction to achieve better decompression. 7. Enteroclysis permits better delineation of the small bowel than that achieved by Barium meal follow through. Segmentation of the barium column and flocculation is avoided.

Enteroclysis (Small Bowel Enema) • 93

Disadvantages 1. Placement of Nasogastric tube for enteroclysis causes discomfort which can be minimized by tranquillisers. 2. Extrapyramidal symptoms of Metaclopramide can be made to subside by giving benadryl (or Atropine). 3. Nausea and vomiting due to inadequate tube placement proximal to treitz ligament. - Treatment: Aspiration of contents by withdrawing the tube into the stomach. 4. Rapid colonic emptying. 5. Use of Barium as primary contrast agent. 6. Operator dependent. 7. Failure to depict extra-intestinal changes.

AFTER CARE The patient should be warned that diarrhoea may occur as a result of the large volume of fluid given. Patient can take full diet following the procedure.

COMPLICATIONS 1. Aspiration. 2. Perforation of the bowel.

Anatomical differences between small bowel and large bowel Small bowel Valvulae conniventes Present Numbe, of loops Many � Central Distribution of loops- ---Haustra - - -Absent Diameter 3-5 cm Absent Solid faeces

t-

-1

Large bowel Absent Few Peripheral Present 5 Cm Present

Present status of barium studies versus capsule endoscopy, iloescopy, CT and MR enteroclysis. Capsule Endoscopy • Capsule endoscope offers high diagnostic results in IBD, ulcers, polyp, erosions.

94 • Radiological Procedures

Advantages • No radiation exposure. • Minimal patient discomfort. • Less operator dependant.

Disadvantages • Inability to control the camera. • Biopsy can not be taken. • Capsule may not reach caecum in cases of stricture hence incomplete examination.

Ileoscopy Endoscopy examination limited to distal ileum.

Advantages • Biopsy can be taken.

Disadvantages • Inability to reach caecum. • Inability to intubate ileum during colonoscopy.

CT ENTEROCLYSIS • An 8-F nasojejunal tube is positioned in the duodenojejunal junction. Diastilled water is infused with a pressure controlled pump. Patient is given intravenous antispasmodic to reduce the motion artefact caused by bowel peristalsis. C.T. enteroclysis is many times combined with LV. contrast study. Helical scanning is started 70 seconds after the administration of I.V. contrast whenever indicated. Reformatted images are obtained in sagittal and oblique planes. Advantages of CT Enteroclysis over Conventional Enteroclysis • CT Enteroclysis allows better detection of intraluminal, intramural or extramural pathologies e.g.polyps, mass, liver, metastasis, lymph nodes. • Lesions as small as 5-35mm can also be detected. • Bowel wall thickness can also be measured. • Detection of enteric fisulous tract, stenosis is possible.

Enteroclysis (Small Bowel Enema) • 95

MR ENTEROCLYSIS • The basic procedure is same. • MR Enteroclysis can be performed with both iron based and positive gadolinium contrast agents.The use of methylcellulose in water as enteric contrast agent with Gd-DTPA is preffered because it acts as biphasic enteric contrast agent with low signal intensity on Tl WI & high signal intensity on T2WI.

Advantages of MR Enteroclysis • High sensitivity for high grade small bowel obstruction for eg: ulcerative colitis, crohn's disease. • Bowel wall enhancement provided by gadolinium allows assessment of inflammatory disease activity eg: ulcerative colitis, crohn's disease. • Real time functional information provided by MR is definitely an advantage over other modalities as we get a 3D image reconstruction. • No radiation involved hence can be useful for paediatric age group & pregnant patients.

Long Answer Questions ----------------1. Discuss enteroclysis under following headings: (a) Definition (b) Indications & contraindications (c) Contrast medium used in enteroclysis (d) Preparation of patient before enteroclysis (e) Equipments used during procedure (f) Describe the technique of double contrast enteroclysis (g) Advantages & disadvantages of enteroclysis

Short Answer Questions----------------1. What are the indications & contraindications of enteroclysis? 2. Mention the variations in barium preparations used for (a) Single contrast enteroclysis (b) Double contrast enteroclysis (c) Air double contrast enteroclysis 3. Which drugs are to be discontinued before enteroclysis examination? why?

96 • Radiological Procedures

4. What is the role of preliminary plain radiograph of the Abdomen before enteroclysis examination? 5. Describe bilbao-dotter tube. Describe the procedure of tube placement. 6. What is treitz ligament? Describe shortly its role in enteroclysis. 7. What are the problems encountered during enteroclysis procedure? How do you overcome these problems? 8. Compare methyl cellulose DC with air DC enteroclysis. 9. Describe briefly - CT enteroclysis/MR enteroclysis

REFERENCES 1. Freeny PC, Stevenson GW (eds). Marguilis and Burhenne'sAlimentary Tract Radiology, 5th edn. St. Louis : Mosby, 1994 : 534-550. 2. Nolan DJ. Small intestine. In: Graham H Whitehouse (ed). Techniques in diagnostic imaging, 3rd edn. Oxford : Blackwell Science, 1996 35-44. 3. Dean D.T. Maglinte, Frederic M. Kelvin, Micheal obstruction : optimizing Radiologic investigation and Non-surgical management. Radiology, Jan 2001, Vol. 218. Number 1 : 39-46.

Chapter 10

Barium Enema • • • • • • • • • • • • •

Definition Contrast Preparation Positions Double Contrast Barium Enema (DCBE) Single Contrast Barium Enema (SCBE) Special Barium Enema Studies Aftercare Complications Virtual Colonoscopy CT Colonoscopy MR Colonography References

DEFINITION It is the radiographic study of the large bowel by administration of the contrast medium through the rectum. CONTRAST Pure crystals of Barium sulphate are formed by milling of the mined raw mineral barytes, precipitation with sulphuric acid, followed by washing and drying. Particle size varies from 0.6-1.4 microns (fine and uniform) to 4-50 microns (large crystal in more heterogeneous form). Particles are coated with various agents to achieve rapid flow, good mucosa! adhesion, adequate radiographic density, an even coating which is plastic and does not crack and absence of artifact or foaming. Additives - Carboxy Methyl Cellulose - Simethicone, Gum acaeeae, Pectin - Dimethyl Polysilicone (anti foaming agent)

97

98 • Radiological Procedures

PREPARATION There are different regimes of bowel preparation and most regimes rely on a combination of dietary restriction, purgation and overhydration with the possible addition of cleansing water enema.

Diet Patient should be given a low residue (low fibre) diet for 2 days prior to the examination. Patient should not have any fatty fried foods. He should not have vegetables and fruits. Patient can have egg, meat, dal and soups. Patient should drink plenty of clear fluids on the day preceding the examination. Iron containing medication should be stopped 2 days before the examination because they make stools adhere to mucosa.

Laxatives (For removal of most solid material)

Castor Oil (30 ml) • irritant cathartic. • cheap, though unpleasant to take, is gentle in effect. • has dual action, being broken down in the small bowel into : (i) Ricinoleic acid, which inhibits water reabsorption; (ii) Mineral oil residue that probably has a direct motor action causing contractions in the distal small bowel and proximal colon.

Bisacodyl (15-20 mg) • irritant cathartic • contact laxative belonging to polyphenolic group of compounds • hydrolysed by intestinal enzymes in the small and large bowel into desacetyl bisacodyl which has a direct motor action on the bowel and also a slight secretory effect. E.g.: Dulcolax.

Magnesium Citrate (5-10 mg) • saline type cathartic is more pleasant to take than magnesium sulphate. • magnesium and the sulphate or citrate radicals are poorly absorbed from the gut, leading to osmotic retention of fluid and increased peristalsis. E.g.: Picolax (one sachet contains 10 mg of sodium picosulphate, 3.5 g of magnesium oxide and 12 g of citric acid).

Barium Enema • 99

• It is a contact and osmotic laxative. • Headache is its most common side effect. E.g.: Citramag (Magnesium citrate equivalent to 5 g of Mg Oxide).

Bowel Wash

• Previous night. • In the morning, 2 hours prior to the procedure. • Pass the tube beyond the rectosigmoid junction and infuse about 1.5-2 litres of fluid allowing evacuation. Repeat this till efflux is clear of any faecal matter. T his is done for removal of smaller particles. • Patient lies: Left lateral position-receiving first 500 ml. Prone position-receiving second 500 ml. Right lateral position-receiving third 500 ml.

Preparation of Patient in our Department 1. Tab. dulcolax 2 HS - 2 Days. 2. Tap water enema on previous night and 7 a.m. on the day of investigation. 3. Low residue diet - 2 Days. 4. To come on empty stomach on the of investigation.

Preparation of the Patient should not be done in 1. 2. 3. 4.

Diarrhoea. Total obstruction. Paralytic ileus. Children less than 8 yrs. of age.

POSITIONS Part of the bowel Rectum and presacral space Rectosigmoid Splenic flexure Hepatic flexure Entire colon

SCBE Left lateral Frontal-prone Prone right side down oblique Prone left side down oblique Prone right side down oblique Supine

DOUBLE CONTRAST BARIUM ENEMA (DCBE) First modern double contrast barium enema with air insufflation wus performed by Fischer in 1923 and later popularized by Welin in 1960s.

100 • Radiological Procedures

Preliminary Films Plain radiograph of the abdomen is essential and helps in assessing any abnormalities of gas filled bowel loops. In the presence of residual faecal matter, double contrast examination should be cancelled. In many centres, barium enemas are performed after an excretory urogram. This not only reduces the time of hospitalization but also gives relationship of the urinary system to the colon. It also helps in visualization of the bladder in frontal and lateral projections and this permits the study of the space between bladder and rectum. Indications 1. Preferred method for routine examination. 2. High risk patients - rectal bleeding, previous H/o carcinoma or polyp, family H/o colorectal cancer or polyposis. 3. Demonstration of sinuses or fistulas. 4. Patient with severe diverticulosis, polyposis or diarrhoea. 5. Presence of obstruction. 6. Reduction of an intussusception. Contraindication 1. Allergy to barium suspension. 2. Peritonitis. 3. Acute or fulminating inflammatory colon disease. 4. Debilitated, unconscious, inability to cooperate. 5. History of recent rectal/colonic biopsy. Procedure Barium suspension : High density (slower flowing, better coating) 75% to 95% w/v. The patient is in prone position with left side down oblique and high density low viscosity barium suspension is allowed to flow upto splenic flexure. Now air is introduced with patient prone. Air should push the barium column and never pass beyond the column. The role of IV muscle relaxant before or after the double contrast barium study had found to have no effect on the mucosa! coating. Frontal view of rectum is taken in prone position and then the patient is turned left lateral to take the lateral view. Then oblique right side down view for rectosigmoid junction is taken. The patient is taken back in prone position with right side dependent and air is pumped into

Barium Enema• 101

left sided colon. Once barium comes into transverse colon tum the patient left side up - barium enters right sided colon and reaches the ileocaecal junction. Now with the right side up, more air is pumped till air outlines the ileocaecal junction. Take spot films for flexures and ileocaecal junction. Now proceed with full films in supine, both decubitus and erect as required.

Advantages of Double Contrast Over Single Contrast • Better surface details. • Surface lesions can be demontrated to the best effect. • Easy unraveling of the colon as it is possible to look through loops. Disadvantages of Double Contrast Over Single Contrast • Difficult in uncooperative patients. • Fistulae/sinuses can be missed. • Effacement of submucosal detail of the colon and overlooking of annular /polypoid lesion is possible. Note: 1. If colon repeatedly gives contraction, Buscopan 1ml i.v. can be given. 2. If patient does not retain barium, then for better retention : • make patient prone. • distend the colon slowly. • reassure the patient. • if there is sphincter incompetence, then strap the buttocks with sticking plaster. • use Foley's catheter with big balloons. The balloon is inflated in mid rectum and then gently pulled back till there is resistance­ do not use balloon in acute inflammation. 3. In patients who have total obstruction, let patient evacuate part of the barium and then pump air. The froth goes through the obstruction and proximal limit of obstruction can be demonstrated. SINGLE CONTRAST BARIUM ENEMA (SCBE) Indications 1. Uncooperative, very debilitated or immobile patient. 2. Evaluation of acute obstruction or volvulus. 3. Reduction of intussusception.

102 • Radiological Procedures

4. Show configuration of colon. 5. Where only gross pathology is to be excluded. Contraindications 1. Allergy to barium suspension. 2. Risk of perforation. 3. Peritonitis. 4. Suspicion of acute/fulminating ulcerative colitis. 5. Following a recent deep biopsy. Procedure Barium suspension : Low density (to promote see through effect with a high kV or compression) 15% to 20% w/v. Tube is placed in the rectum with the patient in left lateral position. The height of the enema should not be more than 1 metre above the table top. In case there is gas in the rectum, the patient is kept supine and infusion is started. Otherwise the patient is kept in left lateral position. As soon as the entire rectum is full, the tube is clamped and a lateral view is taken. Then the patient is put prone and with the infusion running, the frontal view film of the rectum is exposed. In the prone position, pelvis tilts forward, sacrum lies parallel to the film and foreshortening of rectum is prevented. The patient is kept prone with right side down oblique position. This position helps in the opening up the curve of rectosigmoid junction. Spot views of rectosigmoid junctions with barium flowing are taken. Now the patient is kept prone oblique with left side down. Splenic flexure opens out and spot view of splenic flexure is taken. As barium flows towards hepatic flexure, patient is turned right side down oblique and spot films of hepatic flexure. With continuous flow of barium caecum fills up. As soon as the reflux across ileocaecal junction takes place, the tube is clamped and ileocaecal spot films are exposed. A full film is now exposed to show entire colon. After evacuation, mucosal relief film is exposed. Polyposis and diverticulo­ sis can be better visualized on post-evacuation films. Pelvic outlet view for rectum : Give 30° cranial angulation to the tube with the patient supine so that pubic symphysis and sacral promontory overlap. Pelvic inlet view for sigmoid : Should be taken before the transverse colon is filled with barium. 30° caudal tilt is given to the X-ray tube with patient supine.

Barium Enema• 103

Note: During the entire study, the head of the barium column should be followed under flouroscopy. A limited double contrast study can be done following conventional study but it is technically inferior to a direct DCBE. (Our department follows this technique) • Patient evacuates after SCBE. • Adequacy of evacuation is checked. If the evacuation is near total, about 300-400 ml of barium is again filled. • Now air is pumped in from the rectum under fluoroscopy and double contrast filming is done. • If there is a large amount of residual barium, then supine, right and left decubitus, frontal films, and if required, erect films should be taken.

Absolute Contraindications for Both DCBE and SCBE • Toxic megacolon. • Pseudomembranous colitis. • If rectal biopsy has been done in the previous 5 days, it is preferable to wait for 7 days. • Paralytic ileus. • Difficulty to pass tube in rectum. For example, inflammed piles, growth etc.

Relative Contraindication • Incomplete bowel preparation.

SPECIAL BARIUM ENEMA STUDIES Sigmoid Flush It is used in patients with severe diverticular disease to improve visualization of affected bowel. 500-700 ml of dilute barium suspension is run in at the end of standard DCBE and spot radiographs are taken of the filled sigmoid and descending colon. The numerous rings formed in DCBE are easier to interpret in SCBE. The dense barium adheres to the mucosa while the dilute suspension gives a see through effect.

Colostomy Enema A non-wash out bowel preparation is strongly advised in patients with a colostomy. Standard barium suspension may be used. Cut

104 • Radiological Procedures

the balloon of a Foley's catheter and then fit an infant bottle feeding nipple over this after having cut a suitably sized hole in the end. Catheter is advanced for about 15 cm through the nipple and is then inserted into the stoma until nipple acts as a bung in the stoma. Some guaze swabs with a central cut are placed around the nipple and the patient's hand is used to hold this in place. The suspension is run through the main tube and gas is introduced through the side arm. Alternative techniques include using a Foley's catheter with its balloon inflated to seal the stoma or with a hole made in the colostomy bag itself. Colon is filled till mid-transverse colon. Then patient is turned to right side and gas is insufflated. Rotate the patient to manipulate the column around the hepatic flexure and bring the barium to ascending colon. It is important to turn the patient prone. Spot radiographs taken are supplemented by two decubitus views.

Instant Barium Enema It is done to show the extent and severity of known colitis. No bowel preparation is required as residue does not accumulate in a segment of active colitis. Technique works best in ulcerative colitis where disease is continuous but gives acceptable results in Crohn's disease. A preliminary plain radiograph is recommended to exclude toxic megacolon or perforation which are absolute contraindications to an instant barium enema. Colon should be filled until residue is encountered or the transverse colon is reached. Rectum is drained and gas is very gently insufflated turning the patient as required. A prone radiograph is all that is required. Lateral pelvic view will show size of rectum and an erect radiograph, the flexures and transverse colon in double contrast. Balloon catheters are contraindicated. Water-Soluble Contrast Enema Gastrografffin (meglumine diatrizoate) or similar products are used as enema contrast media for certain conditions. Normally it is used as 1:3 dilution with water. Indications 1. Intestinal perforation due to diverticulosis, perforated carcinoma, leaking anastomosis and abdominal stab wounds communicating with colon. 2. Fistulas (vesicocolonic, vaginocolonic)

Barium Enema • 105

3. Softening of meconium in newborns and to relieve faecal impaction in adults. Hyperosmolar nature of gastrograffin may produce severe dehydration, shock and death in: • hypovolemic infants. • sick children. • very old and very ill.

AFTERCARE 1. The patient should be warned that his bowel motion will be white for a few days after the examination. 2. Laxatives should be used to avoid barium impaction in patients with constipation. COMPLICATIONS Can result from: • Preparation of patient • Pharmacological agents • Procedure Perforation • balloon catheters may cause local trauma to rectum. • patients with colitis, radiation therapy and where there is low anastomosis are more prone for perforation. • perforation may be intraperitoneal or extraperitoneal. • in intraperitoneal-massive serosal fluid exudate with hypovolaemia will occur which may be compounded by Gram negative endotoxic shock. • barium sulphate particles in peritoneal cavity will cause foreign body reaction with formation of dense adhesions. • barium granuloma - due to barium retention within bowel wall from intramural perforation • rarely venous intravasation • if barium enters systemic circulation, pulmonary embolism will result. Treatment: antibiotics, fluid replacement and peritoneal lavage.

106 • Radiological Procedures

Inspissation of Barium • Causing severe constipation to the patient. • It is seen in elderly patients with obstructive lesion or if barium is given in large amount and infused beyond the lesion. • Usually results from residue impacting in a stricture and high intracolonic pressures generated by the purgative exceeding the integrity of the bowel wall. Prevention: Fluid should be forced and laxatives should be used after the procedure.

Water Intoxication and Electrolyte Imbalance • Due to preparation with cleansing water enema.

Caustic Colitis • Due to detergent or soap enemas being used, as these interfere with mucosal coating.

Transient Bacteremia • Following instrumentation/ dilatation of the colon.

Pharmacological Agents Causing Complications • Buscopan: ctry mouth and in 10% of patients there is blurring of near vision, which lasts for about 20 minutes. • Sensitivity to barium suspension is very rare. • Anaphylactic reactions to latex balloon catheters have been reported (silicon rubber catheters are the alternative).

Colonoscopy • This exam involves placing a flexible endoscope into the colon. • Intervention is possible, biopsies can be taken and polyps can be removed. • Colonoscopy is generally considered the procedure of choice for colon cancer screening.

Computed Tomography • It offers better density discrimination. • It allows visualization of the wall of the gut. • It permits demonstration of structures beyond the alimentary tube, thus allowing assessment of extent of disease.

Barium Enema• 107

• It provides reconstruction of images in various planes. • It is an excellent method for needle biopsy of lesions of colon.

VIRTUAL COLONOSCOPY Virtual colonoscopy, also known as CT colonography, refers to using spiral CT scanning or multidetector CT and computers to simulate colonoscopy by generating high-resolution multidimensional views of the colon. Advantages 1. It is less invasive. 2. It offers greater safety, less discomfort, and greater patient acceptance. Disadvantages 1. Main disadvantage is increased cost and is inability to take biopsy. 2. It has poor sensitivity for small polyp. CT COLONOSCOPY In this procedure entire colon is visualized by C.T. examination with 3 D reconstruction. Indications 1. When colonoscopy could not be performed ( eg. In case narrowed bowel, In a case of colonic obstruction to see the part distal to obstruction.) 2. Elderly and sick patients. 3. Patients who are at increased risk of complication, due to colonoscopy such as patient on oral anti coagulant. 4. Poor patient compliance during conventional colonoscopy. Advantages 1. No anaesthesia, sedation required and high patient compliance. 2. Minimally invasive procedure with clear detection of polyp and other lesions. 3. Markedly lower risk of perforating the colon. 4. Abnormalities outside colon can also be well visualized.

108 • Radiological Procedures

MR COLONOGRAPHY Currently three different liquid enema techniques are used for MR colonography: 1. Bright lumen. Water gadolinium enema is used. 2. Black lumen. Water enema for luminal distension and intravenous infusion of gadolinium for enhancement of the colonic wall. 3. Fecal tagging. Based on die that contains barium to give stools the same signal intensity as water on TlWt GRE image.

Advantages 1. For detection of crohn's disease, sensitivity and specificity is very high. 2. MR colonography with fecal tagging can detect smaller lesions from 6 mm in size. 3. No radiation involved.

Long Answer Questions-

� - - - --------- -

1. Discuss barium enema under following headings: (a) Definition (b) Preparation of patient (c) Contrast media used during procedure (d) Indications & contraindications of S.C.B.E. (e) Indications & contraindications of D.C.B.E. (f) Complications of barium enema. 2. Describe S.C.B.E. and D.C.B.E. under following headings: (a) Preparation (b) Contrast media used during each procedure (c) Indications & contraindications (d) Procedure (e) Complications

Short Answer Questions--------- - - - ---1. Write a short note on water soluble contrast media. 2. What is barium enema? How will you prepare a patient for this procedure?

Barium Enema • 109

3. 4. 5. 6.

Discuss in brief complications of barium enema. Mention the indications & contraindications of D.C.B.E. What is the role of preliminary film before D.C.B.E.? Mention the advantages & disadavantages of D.CB.E. over S.C.B.E. What are the absolute contraindications for both?

REFERENCES 1. Freeny PC, Stevenson GW (eds). Marguilis and Burhenne's Alimentary Tract Radiology, 5th edn. St. Louis : Mosby, 1994 : 696-714. 2. Bartram Cl. Colon. In : Graham H Whitehouse (ed). Techniques in diagnostic imaging, 3rd edn. Oxford : Blackwell Science, 1996 : 50724. 3. E.M. Elson, D.M. Campbell, S. Halligan, I.Shaikh, S. Davitt, Cl. Bartram. The effect of timing of LV. Muscle relaxant on the quality of Double contrast Barium enema. Clinical Radiology, May 2000; Vol. 55. No. 5 : 395-397.

Chapter 11

Hysterosalpingography • • • • • • • • • •

Indications Contraindications Equipment Procedure Technique After Care Complications Falloposcopy Sono Salpingography (Sion Test) References

It is the procedure in which the contrast is injected into the uterus to study the uterine cavity and fallopian tubes. INDICATIONS 1. Infertility: • To demonstrate patency of the fallopian tubes and their communication with the peritoneal cavity. The causes of tubal blockage are obstruction following tubal infection, fimbrial adhesions, tubal pregnancy, tumour and sterilization procedures. Poor operative technique and tubal spasm may give false appearance of tubal blockage. • Prior to artificial insemination. 2. Recurrent abortions: To demonstrate congenital abnormalities of the uterus or incompetence of the internal os of the uterus. 3. Following tubal surgery: To monitor the effect of tubal surgery. For example, to confirm tubal occlusion in a sterilization procedure or to demonstrate patency and length of falloplan tubes after surgical intervention to restore patency of pathologically obstructed tubes. 4. Migrated IUCD.

110

Hysterosalpingography • 111

5. Uterine and tubal lesions like tuberculosis, submucous fibroids, polyps, synechiae.

CONTRAINDICATIONS • • • • • • •

Active Pelvic Sepsis. Sensitivity to contrast media. Recent dilatation and currettage. Pregnancy. The week prior to and the week following onset of menstruation. Severe renal or cardiac disease. Cervicitis/purulent vaginal discharge.

EQUIPMENT • Contrast Media: Water soluble. For example, Urograffin 60%, Conray • • • • • •

280, Trivideo 280. Volume 10-20 ml. (Average volume 5-6 ml, in nulliparous women 3-4 ml, if there is hydrosalphyx > 10 ml). 20 cc syringe. Canula: Leech Wilkinson, Jarcho type, Spackman. Uterine sound and dilator. Sims speculum. Tenaculum: Trauma is less, so ideal for nulliparous women. (Vulsellum forceps can also be used but trauma is more). Fluoroscopy unit with spot film devices.

PROCEDURE Ideal Time of Procedure: Between 8th and 10th day of menstrual cycle, i.e., 2-3 days after stoppage of menstruation so that menstruation tissue or fluid is not carried either into the oviduct or the peritoneal cavity and the incidence of intravasation of contrast is low. Done before 12th day because oocyte undergoes meiosis during this time and is radiosensitive. Thus radiation exposure during this time should be avoided. Patient Preparation: The patient should be advised to abstain from intercourse between booking the appointment and the time of examination unless a reliable method of contraception is used to avoid the possibility of irradiating an early pregnancy. Patient should be fasting 4 hours prior to the procedure.

112 • Radiological Procedures

Premedication: Premedication is not required in majority of the cases. When the patient is very anxious, 5-10 mg of I.V. diazeparn 30 minutes before procedure is helpful to prevent the tubal spasm which can be provoked by anxiety. Morphine and Pethidine should not be given as they stimulate the contraction of the fallopian tubes. However Baralgan, which contains analgin and pitafemone HCl in 2 ml ampoule or 0.6 mg atropine sulphate in 1 ml ampoule can be given I.V. 10 to 15 minutes before starting the procedure. The bladder should be emptied prior to HSG. A full bladder will elevate the fallopian tubes and may cause apparent tubal blockage with the spurious radiological appearance of a hydrosalpinx. TECHNIQUE • Using a canula. • Using Foley's catheter.

Using a Canula The patient is placed in lithotomy position at the edge of the X-ray table. A speculum is introduced into the vagina and the anterior lip of the cervix is held with tenaculurn and gentle traction is applied. The canula is inserted into the cervical canal under direct vision. The speculum is then removed and patient is carefully moved up the X-ray table in supine position. Care must be taken to remove all the air bubbles from the syringe and canula before injecting, as these may mimic polyps or fibroids. Under fluoroscopic control, 2 ml of the contrast media is injected to outline the uterine cavity. To prevent leak from the cervix, a downward traction should be kept on the tenaculurn while keeping an upward pressure to the canula. The injection is then continued slowly governed by the patient's tolerance until the oviducts have been outlined and free intraperitoneal spill of the dye is visualised.

Filming: • As the tubes begin to fill. • When peritoneal spill has occurred. Maximum X-ray screening time must not exceed 30 seconds using an image intensifier and only two X-ray plate exposures are permitted in order to minimize radiation to female gonads. (70-90 kV range)

Hysterosalpingography • 113

Using Foley's Catheter Cameron et al have described a method using 8 F Foley's catheter. The cervix is exposed with a vaginal speculum and swabbed with an antiseptic solution with the patient in lithotomy position. After the lumen of the catheter is filled with the contrast (to prevent air bubbles) the catheter is inserted through the cervical os using a cervical forceps to guide it when the ballon lies within the uterine cavity, it is gently inflated with water (2-3 ml). Before the injection of contrast, the ballon is pulled downwards against the internal os. The speculum is withdrawn and the catheter is attached to the syringe. The patient assumes a more relaxed supine position. Contrast injection and filming is same as with using a canula.

Advantages 1. No need for tenaculum thus avoiding possible cervical trauma and bleeding. 2. Ability of a single operator to control both the injection and exposure of spot films on a conventional fluoroscopic machine. 3. Much easier to obtain spot radiographs because the patient is in more comfortable position and there is no chance of obscuring anatomy with metal artefacts. 4. A "drainage" radiograph can be obtained at the end of the procedure to demonstrate the uterine cavity without the catheter creating artefacts. 5. Avoids false passage formation. 6. Avoids potential uterine perforation.

Disadvantages 1. The tip of the catheter sometimes blocks the tube on one side. This can be avoided by applying downward traction on the catheter while injecting the contrast. 2. The part of the uterus adjacent to the bulb cannot be studied. For visualization of the lower uterine segment and the cervical canal which are obliterated by balloon catheter, the balloon may be deflated gradually while simultaneously injecting the radioopaque dye. False positive result is seen in hydrosalpinx. False negative result is due to tubal spasm. Tubal spasm is seen in response to anxiety or injecting the contrast with pressure. To eliminate tubal spasm, sublingual nitroglycerine, general anaesthesia, narcotics, tranquillizers and adrenalin or glucagons may be given.

114 • Radiological Procedures

For peritubal adhesions HSG has high false positive rates. Note: Lack of tubal fitting in a patient with no known tubal surgery (or) infection is a non-specific finding on HSG. Differential Diagnosis - Anatomic obstruction - Technical problem - Cornual spasm. - Possibly mucosal plugging. Contrast may loculate around fimbrial adhesions and mimic a hydrosalphinx.

AF TER CARE • It must be ensured that patient is in no serious discomfort before she leaves. • She must be cautioned that there may be mild bleeding per vagina for 1-2 days. • For mild pain analgesics may be given. COMPLICATIONS 1. Pain may occur at the following times : • Using the vulsellum forceps. • During insertion of canula. • With tubal distension and distension of uterus. • Generalised lower abdominal pain due to peritoneal irritation by the contrast media. 2. Venous intravasation due to: (0.6 to 3.7%) • Excessive injection pressure. • Traumatization of the endometrium by the tip of the cannula. • The examination performed when the endometrium is deficient as after curettage (or) menstruation. 3. Trauma to the uterus due to canula causing perforation. 4. Exacerbation of Pelvic Infection. [over all infection rate 0.25 to 3% after procedure] FALLOPOSCOPY Falloposcopy is a recent development, pioneered by Dr. Kerin of USA. In this method, a very fine flexible fiberoptic tube is guided through

Hysterosalpingography • 115

the cervix and uterus into each fallopian tube, thus allowing the visualization of the inner lining of the entire length of the fallopian tube. This can provide useful information about the extent of tubal damage, and the possibility for successful repair.

SONO SALPINGOGRAPHY (Sion test) Premedication - same as above Technique Foley's catheter (SF) is introduced into uterine cavity with the patient in supine position. The bulb of the catheter is inflated with 2 ml of normal saline. Transvaginal sonography of uterus with catheter insitu is performed in sagittal and coronal planes. After scanning the uterus and ovaries, the area between the comua of uterus and the ovary on one side is focused upon. A mixture of normal saline and air is pushed with moderate force into uterine cavity using a 20 cc syringe fixed to the metallic adaptor. A slight traction is given to the catheter while injecting to occlude internal os with the bulb. If the fallopian tube is patent the flow can be seen as a gush of fluid cascading past the 'surprised' ovary and this phenomenon is called the 'Water Fall Sign'. Then the same procedure is repeated with the other side focussed. When the tubes are blocked, the patient complains of acute pain in the suprapubic region and , the reflux of fluid and air is seen in the stem of the catheter. Also uterine cavity can be seen distending in case of tubal block.

Advantages • Can demonstrate the tubal block, its site and extent with higher accuracy and reliability. • No radiation exposure. Disadvantages • Individual tube evaluation sometimes become difficult. Other Techniques 1. Harris uterine injector (HUI) 2. Angiodilator techniques 3. Jarcho type canula 4. Sheath needle catheters 5. Malmstrom vaccum apparatus 6. Spackman canula

116 • Radiological Procedures

Long Answer Questions------ ---- 1. Discuss hysterosalpingography under following headings: (a) Definition (b) Indications (c) Contraindications (d) Equipment required (e) Preparation of patient (f) Various techniques used (g) After care & Complications

--

Short Answer Questions ----------.------1. 2. 3. 4.

Mention indications of hysterosalpingography. What are the contraindications of H.S.G.? Describe briefly the techniques used in H.S.G. Enumerate advantages and disadvantages of using foley's catheter over canula. 5. Describe briefly about sonosalpingography.

REFERENCES 1. Whitehouse GH. Female genital tract. In : Graham H Whitehouse (ed). Techniques in diagnostic imaging, 3rd edn. Oxford : Blackwell Science, 1996 : 300-311. 2. Whitehouse GH. Imaging in gynaecology. In: RG Grainger, DJ Allison (eds). Diagnostic Radiology, vol.II, 3rd edition. New York: Churchill Livingstone, 1997 : 1956-1957. 3. Maguiness SD, 0 Djahanbakhch and G Grudzinskas. 'Assessment of fallopian tube'. Obs. and Gynaec. Survey, 1991, vol. 47, No. 7 page 589.

Chapter 12

Fallopian Tube Recanalisation Indications Contraindications Timing of Study Instrumentation Preparation Premedication Technique Other Methods Post Procedure Follow Up Complications References

Tubal factors account for 30-40% of female infertility. Obstruction to the uterine end of the fallopian tube is noted in 20% of HSG's. In FTR, a guide wire is passed through a catheter to recannulate the tube and to restore its potency. It is preceded usually by selective osteal salpingography to confirm the presence of block.

INDICATIONS • Unilateral/bilateral cornual block proved by conventional HSG, and/or laparoscopy with chromotubation. Blocks distal to the cornua are not an indication for FTR. CONTRAINDICATIONS 1. Tubal blocks distal to the cornual end. 2. Patients with tubal pathology like hydrosalpinx and abnormal fimbriae. 3 . Patients with history of tubal surgery. 4. Patients with history of PIO causing dense adhesions and scarring .

117

118 • Radiological Procedures

TIMING OF THE STUDY • As for HSG, the follicular phase between 8th and 10th day after the onset of menstruation is selected

INSTRUMENTATION • 850mAs X-ray machine with fluoroscopic facility. • Fallopian tube catheterization set: - Double Balloon canula (Bard's/Mencini's) - Catheter - 0.0028 F Terumo guide wire • Contrast media-Triovideo 280/Conray 280

PREPARATION • Patient should be advised to abstain from intercourse between booking of the appointment and time of examination unless a reliable method of contraception is used to avoid the possibility of irradiating an early pregnancy. Bladder should be emptied before the procedure. (ovarian dose in FTR-0.2-2.15 CGY).

PREMEDICATION • 25 mg Phenergan injection i.m., 0.6 mg Atropine should be given half an hour before the procedure. • Suitable Antibiotic cover is also provided e.g., Doxycyclin. • If patient is still restless, 5-10 mg i.v. of diazepam is given to remove the anxiety.

TECHNIQUE • T he canula is inserted through the cervix into the uterus and is made to stay in position by inflation of the two bulbs, one at the level of the internal os and other at the level of the cervical canal (Fig.l). Contrast media is injected into the canula to confirm the findings of comual end block. Under fluor-oscopic guidance, a catheter (usually 6 F) is advanced through the canula into the opening of the fallopian tube (Fig. 2). A guide wire is introduced through the catheter till it comes at the fimbrial end thereby dislodging the obstruction (Fig.3). A simplified technique of fallopian tube catheterization is described in which the tube is recanalised with a guidewire alone.

Fallopian Tube Recanalisation • 119

• 2-3 ml of contrast media is injected into the fallopian tube to verify the recanalisation. • The procedure is done on the opposite side in cases of bilateral block. • A peritoneal spill on both sides verifies bilateral tubal recanalisation.

OTHER METHODS • Hysteroscopic placement of catheters with laparoscopic guidance. • Sonographically guided transvaginal fallopian tube catheterization. POST PROCEDURE FOLLOW UP • Admit the patient and observe for 12 hours for signs of perforation leading to peritonitis. • Antibiotic cover. COMPLICATIONS • Ectopic pregnancy (10%) in history of tubal disease. • Early tubal reocclusion and strictures. • Perforation and fistula formation. Note: Transcervical recanalization can be used in the management of patients with post operative strictures with underlying inflammatory obstruction and strictures technique is a failure in case of fistulae complicating reversal surgery.

Short Answer Questions---------------1. What are the indications and contraindications of fallopian tube recanalisation? How do y ou prepare patient for this procedure? 2. What are the pre-medications and complications of fallopian tube recanalisation? Describe in brief the technique of fallopian tube recanalisation. REFERENCES 1. Thurmond AS, Rosch J. Non-surgical FTR for the treatment of infertility. Radiology 1990; 174 : 371-374.

120 • Radiological Procedures

2. Thurmond AS. Selective salpingography and FTR. AJR 1991; 156 : 33-38. 3. Novy M , Thurmond AS. Patton P, Uchida. Diagnosis of comal obstruction by transcervical FTR. Fertility and Sterility 1988; 50 : 434. 4. Millward S.F., Claman P., Leader A., Spence J.E. Technical report : fallopian tube recanalization - a simplified technique. Clinical Radiology July 1994; 49(7) : 496-497. 5. Lang E.K. The efficacy of transcervical recanalization of obstructed post operative fallopian tubes. Eur- Radiology 1998; 8(3) : 461-465. 6. Nikolic B , spies J. B., Lundsten M. J., Abbara S. Patient radiation dose associated with uterine artery embolization Radiology. January 2000; 214(1) : 121-125.

Chapter 13

Sialography • • • • • •

Indications Contraindications Equipment Preparation of the Patient Procedure References

This is the study to demonstrate the parotid or submandibular glands by injection of contrast medium into the duct system.

INDICATIONS 1. Calculi. 2. Chronic inflammatory disease. 3. Mass lesion. 4. Obstructive lesion. 5. Penetrating trauma. 6. Strictures. 7. Fistula. 8. Prior to CT evaluation of salivary glands. CONTRAINDICATIONS 1. Allergy to iodine. 2. Acute Sialadenitis. EQUIPMENT 1. Contrast medium-water soluble, ionic contrast media like Triovideo 280,Conray 280 or non-ionic contrast medium such as omnipaque-350. 2. Lacrimal cannula or disposable 22 G (Gelco/Venflon). 3. Lacrimal dilator. Liebreich's double ended lacrimal probe. 121

122 • Radiological Procedures

4. 2 cc syringe. Four grades (00/0, 1/2, 3/4 & 5/6) 00/0 and ½ are required for sialography. Outer diametre of cannula 1.02 mm. Rabinov sialography catheter obtainable in a sterile pack and is recommonded. 5. Lemon/vitamin C tablet.

PREPARATION OF THE PATIENT Removal of false teeth, if any. PROCEDURE l. Preliminary radiograph Plain radiograph should be taken before embarking on sialography because a considerable pathology is associated with opaque calculi within the glands themselves or their ducts, particularly in the submandibular gland. 2. Locating duct openings (a) Parotid duct opens opposite 2nd upper molar tooth on the buccal surface of the cheek. (b) Submandibular duct opens at the base of the frenulum of the tongue. (c) In case the ostium is not visible, apply pressure on the gland or give a sialogogue like lime. Then saliva will be seen pouring through the punctum. 3. Dilate the punctum with lacrimal dilator. 4. Technique Two techniques for cannulating the ducts are by using: (a) Intracath technique. (b) Lacrimal cannula technique. • If we are using an intracath, we should cut enough plastic tubing from the tip of intracath with fine scissors such that 2 mm of the inner wire stilette is still protruding. Now the punctum is cannulated for 5 mm. Now withdraw the stilette such that it no longer protrudes the outer tube. • The inner stilette produces stiffness during introduction of catheter. The stilette is removed and outer tube is attached to polythene tube. • Now the contrast is injected. • In the lacrimal cannula method, contrast is injected into the cannula which is introduced through the duct opening.

Sialography • 123

5.

6.

7.

8.

• Contrast is injected till the patient complains of pain by a prearranged signal. • About 0.5-1.0 cc of contrast is required. Film exposure Positioning for parotids: • Frontal view is taken with face rotated 5-10 degrees towards the side of study. • Lateral view is taken with 15-20 degrees cranial tube tilt. Positioning for submandibular gland • Lateral view is taken with 15-20 degrees cranial tube tilt. Films are taken during injection. The catheter is left in place till the adequacy of films is ensured. Aftercare: none If sialadenitis occurs after the procedure, it should be treated with antibiotics and anti-inflammatory drugs. Complications • Sialadenitis and abscess • Stricture of the ducts. Disadvantages of sialogram • Masses less than 1cm may not be detected. • Contrast does not always penetrate the deep lobe of parotid gland.

Short Answer Questions ----------------� 1. What is sialography? Enumerate indications and contraindication of sialography. 2. Describe the procedure of sialography in brief. REFERENCES 1. Smith NJD. Salivary glands. In : Graham H. Whitehouse (ed). Techniques in diagnostic imaging, 3rd edn. Oxford : Blackwell Science, 1996 : 3-12. 2. Chapman AH. Salivary glands. In : David Sutton. Textbook of radiology and imaging, 6th edn. New York : Churchill Livingstone, 1998 : 789-792.

Chapter 14

T-Tube Cholangiography • • • • •

Indications Technique Pitfalls Interpretation References

A type of direct cholangiography, which allows study of the CBD in the post-operative period prior to removal of T-tube, determining the patency of CBD. If there are no post-operative complications, a T-tube cholangiogram should be obtained 8-10 days after operation. It is estimated that approximately 5% of post-operative T-tube cholangiograms will show retained calculi (Glenn, 1974). If retained stones are detected, percutaneous removal through T-tube tract, as popularized by Mazzariello (1978) and Bushenne (1980) is the treatment of choice.

INDICATIONS 1. Exploration of the bile ducts at operation. 2. Poor or absent drainage of bile from the T-tube after operation to determine whether the T-tube is blocked or is no longer present in the CBD. 3. Haemorrhage from the T-tube. 4. Demonstration of residual hematoma or abscess formation within the liver parenchyma after partial hepatectomy or liver laceration. TECHNIQUE • No patient preparation is required. The examination is done on fluoroscopy unit with image intensifier and a tilting table, 7-10 days after operation/earlier if there is indication for this such as haemorrhage from T-tube/failure of T-tube drainage.

124

I-Tube Cholangiography • 125

The patient is placed supine on the X-ray table with the left side slightly raised. All dressings and metal objects are removed from the liver area. A preliminary film of right upper quadrant should be obtained before injection to establish the position of tube and identify unusual air collections. Sterile technique is used, and a syringe connected to a No. 21 or No. 23 scalp vein needle is filled with contrast material and closely scrutinized to eliminate air bubbles. The I-tube is then punctured and gently aspirated to withdraw air bubbles lodged in the tube. The I-tube should then be clamped just beyond the point of insertion of the needle to prevent distal air bubbles from being mobilized during injection. Dilute contrast medium should be used so that stones are not obscured. If bile ducts are markedly dilated, more dilute contrast medium (CM) should be injected, but overdistension should be avoided. Care should be taken not to introduce air bubbles into biliary tree as they may mimic stones on cholangiogram. Approximately 5 cc of CM is injected under fluoroscopic control and a spot film is obtained in AP projection. Patient is then rotated into the left posterior oblique position and the procedure repeated with an additional 5 cc injection. A further injection is made when the patient is placed in RPO and finally a film is taken with patient supine once again in straight AP. Normally a total of 20-25 cc of CM is sufficient to obtain these special views. After final injection, a right lateral film may be obtained if required. If desired, films are taken at 15min / 30 min intervals depending upon degree of delay in emptying of biliary tract until patency of biliary tract is determined. If obstruction is encountered, it is best to withdraw as much of contrast media as possible prior to removal of the syringe. With a slow injection rate, the patient should experience no pain. A sense of fullness will occasionally be noted. Marked discomfort indicates that either the I-tube is malpositioned or the normal flow of bile is obstructed. If explanation is not evident fluoroscopically, it is best to pause and review the available films before proceeding.

PITFALLS Differentiation between air bubbles and calculi may be made by placing the patient in Trendelenburg and Semierect positions. Not

126 • Radiological Procedures

everything that is round and rises to float is an air bubble. Gall stones do not have to be faceted and cholesterol stones may float in CM. Elseny and Jacobs showed that specific gravity of cholesterol stone is 1.04, which is the greatest specific gravity that native bile reaches, which means stones can hardly float in native bile, but may float after the dilution by contrast. Air bubbles fortunately are never faceted, never sink in bile/contrast medium and typically appear as tiny, perfectly round, smooth, and often multiple lucent defects.

INTERPRETATION Normal T-tube cholangiogram Normally there is free drainage of the CM into the duodenum and there may be reflux of CM into the pancreatic duct. Using this technique, the entire biliary tract is outlined, including any cystic duct remnant. Oblique/lateral views or both are necessary to demonstrate the latter. Abnormal T-tube cholangiogram 1. Failure of CM to enter the duodenum may be due to : (a) Rapid injection of CM resulting in the spasm of sphincter of Oddi. (b) Organic obstructive lesion such as tumor or calculus. When obstructive lesion is encountered, spot films of the area should be taken. 2. Failure of CM to pass into the IHD may result either from concretions obstructing the lumen or orifice of proximal limb of T-tube or CM following the path of least resistance distally. 3. Failure of T-tube drainage after operation may be due to : (a) Occlusion of T-tube by debris. This is sometimes overcome by injection of CM. (b) Malposition of T-tube in CBD. This happens when upper limb of T-tube lies against wall of right or left hepatic duct, usually because the upper limb is too long, which may lead to obstruction of bile flow leading to jaundice. (c) Kinking of the T-tube within the abdomen. (d) One or both limbs of T-tube may lie outside the CBD. Clinically this is suspected when there is failure of drainage, leakage of bile around the tube or a biliary fistula.

T-Tube Cholangiography • 127

4. Haemorrhage from a I-tube post-operatively It may be due to (a) Erosion of small vessel by the tube. (b) Vitamin K deficiency in patient with obstructive jaundice of long duration. 5. Residual calculi in CBD These usually pass down from the intrahepatic ducts more commonly from the left hepatic duct and are found in the upper CBD or rarely at its lower end. 6. Lower CBD obstruction at I-tube cholangiography This is most commonly due to spasm of sphincter of Oddi, owing to rapid injection of CM. It may also be due to : 1. A neoplasm at head of pancreas. 2. Chronic pancreatitis with fibrosis of the lower CBD. 3. A benign stricture after passage of a calculus. 4. Primary carcinoma of the papilla or CBD. 5. A calculus impacted at the sphincter of Oddi.

Short Answer Questions---------------1. What are the indications and contraindications of T-Tube cholangiography? Describe the technique in brief. 2. How will you interpret T-Tube cholangiogram? What are the pitfalls of the procedure?

REFERENCES

1. Radiology of the liver. McNulty, 1977, p. 122- 123. 2. Radiology of the gall bladder and bile ducts. Philip M Hatfield, Robert E Wise, p.103-109. 3. An atlas of anatomy basis to radiology. Isadore Meschan, 1975, p. 911-912. 4. White house Techniques is diagnostic Radiology 3rd (edn.) Blackwell Scientific Publications (1996).

Chapter 15

Percutaneous Transhepatic Cholangiography • • • • • • •

Indications Contraindications Prerequisites Technique After Care Comparison of PTC and ERC References

It is a method of direct cholangiography and provides the most complete and detailed radiographic demonstration of biliary duct system.

INDICATIONS • In presence of bile duct obstruction which has been demonstrated by US/CT where information provided by these studies is insufficient for diagnostic purposes/for planning treatment. • Prior to biliary drainage procedures/stenting. • Undiagnosed jaundice. • Extrahepatic bile duct obstruction due to calculi, strictures and malignancies. • Biliary diseases. • Sclerosing cholangitis. • Chronic pancreatitis. • Post operative fistula. CONTRAINDICATIONS • Ascites-difficulty in puncturing and applying compression, possibility of haemorrhage is high. 128

Percutaneous Transhepatic Cholangiography • 129

• Biliary sepsis-appropriate antibiotic cover, use small volume contrast and establish drainage. • Hydatid disease. • Bleeding diathesis. • Contrast hypersensitivity.

PREREQUISITES Patient Preparation 1. US /CT must be performed prior to PTC, which provides useful information regarding not only to the level of obstruction but also to the assessment of tumor resectability and planning of the most appropriate approach to biliary decompression. 2. Check clotting profile and platelet count. 3. Xylocaine sensitivity test. 4. HIV and HBsAg be tested for. 5. Fasting 4 hours prior to procedure. 6. Start I.V. line and broad spectrum antibiotics (in view of high incidence of bacterial colonization of obstructed biliary system). 7. Premedication 30 minutes prior to procedure. 8. Informed consent.

Equipment 1. Fluoroscopy unit with image intensifier and a tilting table 2. Chiba needle-22/23 G, 15-20 cm long with short bevel, stainless steel needle. TECHNIQUE PTC is performed as a sterile procedure with the patient on a fluoroscopic table which preferably is able to tilt. This is done under local anaesthesia with i.v. sedation and analgesia with appropriate patient monitoring. Two approaches: Right flank approach (Lateral) and epigastric approach. Right Flank Approach A flexible chiba needle is inserted, usually from the right side. The puncture site is slightly anterior to midway between the tabletop and the xiphisternurn; inferior to the right lateral costophrenic angle on

130 • Radiological Procedures

fluoroscopy on full inspiration and superior to the hepatic flexure of the colon on full expiration. The needle is inserted medially through the liver while screening, angulated slightly anteriorly to the coronal plane and directed craniad towards a point midway between the right cardiophrenic angle and the first part of the duodenum which can usually be identified by luminal gas. • Specific vertebral bodies are not appropriate for guidance as their relationship to the liver is variable. Needle movement should be during suspended respiration, end-expiration or end-inspiration, and the different phases of respiration can be used to help direct the needle. • Needle tip is advanced to approximately over the right margin of the spine and then withdrawn incrementally with intermittent suction applied with a syringe connected via a short tubing. • Needle entry into a bile duct is identified by aspiration of bile or injection of contrast medium. • It is important to inject only sufficient contrast media to establish diagnosis, as injecting more in high-grade obstruction will increase risk of septic shock. • Injection of contrast media outside bile ducts should be minimum as it tends to obscure the region of interest, may be painful and can produce pseudo-obstruction of IHBD. • Injection into portal or hepatic veins is recognised by rapid flow of contrast media away from the needle tip. • Injection into lymphatics - narrow irregular channels passing downwards and medially but without typical branching of bile ducts. These have a characteristic fine beaded appearance. • Injection into liver parenchyma - persistent amorphous stain. • Injecting periportally - static branching stain. • Injection into bile ducts - slow 'oil like' flow of contrast medium away from needle tip. With multiple needle passes it is common to produce haemobilia, when this occurs blood stained bile is aspirated which is more viscous than frank venous blood and drips like oil rather than water. • If biliary radicle is punctured in first pass, repeated attempts are made with slight variation in craniocaudal angulation but without withdrawing tip from liver substance. • If gall bladder is punctured accidentally, continue by injecting contrast till gall bladder lumen and CBD are opacified and appropriate films are taken (frontal, 45 degrees, LPO, lateral, Trendelenberg).

Percutaneous Transhepatic Cholangiography • 131

•

•

•

•

• •

After filming, contrast and bile are aspirated out of gall bladder to decompress system. The success rate using fine needle PTC increases with number of passes and increase in number of passes does not increase the incidence of serious complications. As movement in biliary radicles is gravity dependent, various positional manoeuvres are done. LPO and Prone positions are used to opacify left lobe ducts. Following successful duct entry, bile samples should be obtained for bacteriological and if malignant obstruction is suspected for cytological examination. Water-soluble contrast medium (200-300 mg I/ml) is then injected in sufficient quantities to obtain as much filling as possible of the intrahepatic and extra hepatic duct system without using undue pressure. As much bile as possible is aspirated, but if aspiration is difficult without loosing needle position then undiluted CM is used (bile itself produces some dilution). In very dilated systems or if stones are suspected more dilute CM is needed so that stones or ductal anatomy is not obscured. With needle in position, patient can be carefully moved into a LPO position, which helps to fill the more anterior left lobe ducts and feet down table tilt us used to fill the EHBD completely. Films are checked prior to needle withdrawal and then further films are taken in different projections to ensure complete visualization of biliary system. A prone film may be needed to fill left ducts

Epigastric Approach It is preferred when: 1. If only left lobe cholangiogram is required or if right sided PTC has failed to produce left lobe cholangiogram. 2. If there is right lobe atrophy or previous right hepatectomy which results in gall bladder or bowel lying deep to right lateral wall where they are at risk of puncture with a right flank approach.

Pitfalls l. Fnlsc locnlizntion of level of obstruction: Failure to inject sufficient CM or use table tilt and patient positioning can lead to false localization of obstruction rt'cognizcd by presence of hazy margin at level of appc1rent obstruction. 2. l11complctc c/10/i111g1osra111. Opacificatim1 of only right ducts i-; oftL 11

132 • Radiological Procedures

mistaken for a complete cholangiogram. The left ducts lie usually over spine if not opacified even with patient rotation and table tilt then direct epigastric approach is used.

AFfER CARE

1. Ask the patient to lie down on right lateral position, as this gives compression to puncture site. 2. Check pulse and BP ½ hourly for 12-24 hours. 3. Observe for increase in abdominal girth. 4. Observe for signs and symptoms of peritonitis and intraperitoneal haemorrhage.

COMPARISON OF PTC AND ERC PTC

Advantages

ERC

Less expertise needed, Visualization of stomach good duct filling above and duodenum. an obstruction Biopsy of periampullary lesions possible. Simultaneous pancreatogram. Note: Both may be followed by catheter or endoprosthesis insertion for biliary drainage. Contraindications Significant Unfavourable anatomy. coagulopathy. Marked ascites* Pseudocyst* Recent acute pancreatitis* Success rates 98%-dilated ducts Upto 90% (Cotton 1977) 70%-undilated ducts (Harbin et al. 1980) Major 4.1% (Gibson 1988) 2-3% (Cotton 1977) complications Mortality 0.13% (Gibson 1988) 0.1-0.2% (Cotton 1977) * Relative

Percutaneous Transhepatic Cholangiography • 133

Short Answer Questions -

- - ----------

�

1. What are the pre-requisite for percutaneous transhepatic cholangiography? 2. Enumerate the indications and contraindications of percutaneous transhepatic cholangiography. 3. Compare in brief percutaneous transhepatic cholangiography and endoscopic retrograde cholangiography. 4. Describe the technique of percutaneous transhepatic cholangiography. What are the pitfalls of the procedure?

REFERENCES

1. RG Grainger, DJ Allison (eds). Diagnostic Radiology, vol.II, 3rd edition. New York: Churchill Livingstone, 1997: 1209-1211. 2. J.P. Owen. Biliary tract. In : Graham H Whitehouse (ed).Techniques in diagnostic imaging, 3rd edition. Oxford : Blackwell Science; 1996 : 90-95.

Chapter 16

Catheters • Classification • Catheters Used For Different Studies - For Global Injection (Aortogram) - Cerebral Catheters - Visceral Catheters - Coronary Catheters - Renal Catheters - Balloon Angioplasty Catheters • Sterilization Of Catheters • References

Modern catheters are made of polyethylene, polyurethane nylon or other plastic tubing to obtain better torque control and superior strength. A high quality catheter in addition to having good torque response and radio opacity should have flexible atraumatic tip and a low surface frictional resistance for good trackability over a guide wire. Recently, catheters with lubricious hydromer coating have been introduced and may perhaps set a new standard of efficacy for selective and super selective catheterization.

CLASSIFICATION Catheters can be classified as: 1. Diagnostic angiographic catheters. 2. Microcatheters. 3. Drainage catheters. 4. Balloon catheters. 5. Central venous catheters.

134

I :

Catheters • 135

1. Diagnostic Angiographic Catheters Side Holes • Single hole (or 'port') at the end (for very selective injection). • End hole with side holes. • Blocked end with side holes only.

Advantages of having side holes are • Holes clustered near the tip of the catheter helps to concentrate the bolus of contrast medium delivered. • They increase the rate at which the contrast medium can be injected through the catheter. • By dispersing the direction of exit of contrast medium from the catheter they reduce the jet effect of the injection, there by reducing the recoil of the catheter tip. • They minimize the dissection of the artery, for if one or more of the parts are not lying freely in lumen of the vessel, the contrast medium can still escape through the exposed parts.

Sizes Catheters intended principally for abdominal use are usually 6-80 cm in length and thoracic or carotid arteries are usually 100-120 cm in length. Size of the external diameter of the catheters depends on the age of the patients, selective or super selective study and size of the vessels. Catheter size is numbered in Fr. Gauge. (Outer Diameter). 1 F = 0.0131 inch = 0.033 mm 1 inch = 254 mm 1 mm= 0.394 inch Most commonly in adult diagnostic work 5-7 French Catheters are used. All these catheters come with certain numbers on them. As the number keeps on increasing the catheter can be used in more dilated and tortous aortic arch. These numbers denote the curves, e.g., for Hilal catheters. H-1-for young patient H-3-for mild tortousity of aortic arch H-5-for moderate tortousity of aortic arch H-7-for markedly unfolded & dilated arch of aorta In general it is good practice to use the smallest diameter catheter feasible for any particular study to minimize the risk of arterial damage by the procedure.

136 • Radiological Procedures

Shapes (Fig. 1) Examples: 1. 2. 3. 4.

Straight catheter Pigtailed catheter* Cobra shaped catheter* Side winder catheters* etc. (Shepherd) Note: *Represents catheters commonly used in most of the radiology departments.

Fig. 1

CATHETERS USED FOR DIFFERENT STUDIES For Global Injection (Aortogram) 1. Straight catheters 2. Pigtail catheters These catheters are used for injecting a large volume of contrast at a high rate of injection. Thus they have multiple holes.

1. Straight Catheters Straight catheter with multiholes throws a jet from the tip and tends to whip around and thus it may cause arterial wall damage. This can be avoided with pigtail catheter.

2. Pigtail Catheters In ventricles and arch of aorta only pigtail catheter should be used. More the number of holes, more are the chances of distal thrombus formation. Moreover clot may form at the distal end which cannot be detected because the backflow occurs through the side holes. Pressure injections or passage of a guide wire through the catheter may push this clot into the artery. Precaution: Thrombus formation can be avoided by frequent and vigorous flushing. Harwood-Nash

Cerebral Catheters Hinck-Hilal catheter (Head hunter)* Head hunter catheter is mainly used for 4 vessel cerebral angiogram. FOR MORE TORTUOUS AND ELONGATED ARCH

DHN1 DHN2

====D=H=N3==

Fig. 2

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==::, ?

Catheters • 137

Hinck Headhunter

Bentson-Hanafee­ Wilson

Hinck Headhunter

H1P

_I)

H3P

Fig. 3

Fig. 4

S1M1

Kerber

Bentson-Hanafee-Wilson

Fig. 5

138 • Radiological Procedures

4. Bentson Hanafee Wilson OB2, JB3) 5. Simmons (SIM2)* Note: Simmons catheter can also be used for selective visceral angiography.

Visceral Catheters (Fig.7) 1. Shepherd's hook/hockey stick catheter* 2. Cobra head catheter* H3 Hinck Headhunter

Hilal Modified Headhunter

SHK 0.8

)

SHK 1.0

Fig. 7

Fig. 6

Coronary Catheters (Fig. 8) 1. Judkins catheter 0L4, JLSAND JL6) 2. Arnplatz catheters (AL 1-AL 4) 3. Sones coronary catheter

3

Fig. 8

?

Catheters • 139

Renal Catheters (Fig. 9) Selective -Simmons or sidewinder -RDC (Renal double curved selective catheter)* Semiselective: Catheter has 6 side holes just proximal to the tapered part.

2. Microcatheters • • • • •

3 F or smaller. Designed for distal catheterization. Fig. 9 Placed over .010-.018 guide wire. Used mostly for neuro intervention. Helpful in pheripheral intervention to select smaller vessels for embolization or infusion. • They have distal platinum marker but otherwise not very radiopaque.

3. Drainage catheters • Used for drainage of fluid collection including nephrostomy, abscess, biliary gall bladder, pleural fluid, ascites, lymphoceles.

4. Balloon catheters • Either very soft and pliable as occlusion balloon or forgarty balloon to clear thrombosis or can be rigid and used for dilatation (angioplasty). • Balloon for diltation can be divided into 2 main categories regarding the size of guide wire over which they are placed. • The balloon used for coronary angiography and also in peripheral and neuro-radiologic procedures are amaller ones mounted on 0.018 -0.024 size guide wire. • Most peripheral interventions are performed with 0.035 wire balloon system.

Balloon Angioplasty Catheters (Fig. 10) 1. Porst Mann's Korsetts balloon catheter 2. Dotter' s coaxial catheter 3. Caged balloon catheter

140 • Radiological Procedures

4. PVC balloon catheters-Recent*

Fig. 10

5. Central Venous Catheter There are three basic categories of catheters

1. Non-tunnelled catheters • These catheters are placed via central veins (Subclavian and Internal Jugular) by blinded percutaneus technique. • They are used for short term access. 2. Tunnelled catheters. • They can be accessed externally and are designed for long term home use. 3. Implanted subcutaneous port. • These are attached to the port that is buried subcutaneously for stabilization. • They can be used for long term . • Subcutaneous ports are available in single and dual port configuration and may be placed either on chest wall or the upper arm. STERILIZATION OF CATHETERS Before giving for sterilization, catheter should be washed in water and with air jets so that clots in the catheter lumen will come out. Because the rigidity and elasticity of polyethylene disappears above 75 degree C, catheters are sterilized in solutions of quarternary ammonium

Catheters • 141

compounds or by gas. Some germicidal solutions require only 10-15 min. of soaking. Gas sterilization may take several hours. There is some evidence that catheters should not be used for several days after gas sterilization. Teflon, Nylon and Dacron catheters may be autoclaved if temperature does not exceed 121 °C and the pressure is not greater than 15 pounds for 15 minutes. W hen catheters are autoclaved, they should not be coiled in a circle less than 8 inches (20 ems) in diameter because if the coil is too tight, under the heat of steam pressure, the coating may crack or split at stress points.

Short Answer Questions---

-----

----� -

1. Classify Catheters. Write a short note on their sterilization. 2. Descibe the diagnostic angiographic catheters. 3. Write in brief about • Micro catheters • Drainage catheters • Balloon catheters • central venous catheter.

REFERENCES 1. Stanley Baum, Michael J Pantecost, eds. Abram's angiography lnterventional Radiology, vol. I, 4th ed. Boston : Little, Brown, 1997 : 155-175. 2. David Allison. Arteriography. In : RG Grainger, DJ Allison (eds). Diagnostic Radiology, vol. III, 3rd edition. New York : Churchill Livingstone, 1997 : 2437-2457.

Chapter 17

Angiography • • • • • • • • • •

Indications Contraindications Patient Preparation And Precautions Local Anaesthesia Direct Needle Puncture + Injection of Contrast with Needle in Situ Catheter Angiography Percutaneous Transluminal Angioplasty CT-Angiography MR-Angiography References

It is the study of the blood vessels by injection of a contrast medium into the vessel. This can be done in two ways: • Direct injection of contrast with needle insitu • Injection of contrast with catheter insitu (catheter angiograrn)

INDICATIONS 1. Primary vascular diseases like : (a) Vasa-occlusive deseases. (b) Vasospastic disease. (c) Aneurysms. (d) AVM Arteriovenous Malformations. (e) AVF Arteriovenous Fistulas. 2. Vascularity assessment of a tumour. 3. Investigating source of haemorrhage. 4. Congenital vascular condition. E.g.: coarctation, abnormal origin of vessels etc.

142

Angiography• 143

5. Pre-operative definition of vascular anatomy. E.g. : Organ transplantation, Vascular tumour excision. 6. Percutaneous interventional vascular procedures.

CONTRAINDICATIONS 1. Bleeding tendencies or anticoagulant therapy leading to a prothrombin time above 30% of the control values. 2. Pulse not palpable at the vascular access site . 3. Thrombogenic tendency. 4. Skin infections or swelling at site of entry. In case of this, alternate entry site is selected. 5. Abnormal renal function. If patient is in CRF then it is better to put the patient on dialysis after doing the angiogram. 6. Cardio Vascular diseases like recent MI, overt CCF. Contrast injection may exacerbate cardiac failure. 7. Hepatic failure . 8. History of allergy, skin rashes or asthma. 9. Pregnancy. 10. Residual barium from previous studies.

PATIENT PREPARATION AND PRECAUTIONS 1. Careful history and clinical examination. 2. 3. 4. 5. 6. 7.

Informed consent. Patient should be well hydrated. Fasting 4 hours prior to procedure. Shave and clean the arterial puncture !':>ite. Xylocaine sensitivity test. Following investigations to be done : • Hb% and Haematocrit and platelet count • ESR • PT, PTT, BT and CT • HBsAg and HN • Pulse chart • General examination and bruits, if any, should be noted • If patient is on Warfarin, it should be stopped 4-6 days before procedure

144 • Radiological Procedures

• If any H/ o heparinization, heparin should be stopped 4-6 hours before procedure • PTT 1.2 x control, is acceptable • Any history of drug intake • History of diabetes mellitus • History of coronary heart disease

LOCAL ANAESTHESIA 1%-2% xylocaine without adrenaline is used. After intradermal and subcutaneous infiltration, needle is advanced at 45 degree angle to the skin surface, with the femoral artery fixed with 3 fingers, 3-4 ml is infiltrated medial to the artery. Care should be taken not to inject in the femoral vessels, by aspirating prior to the injection. Then 3-4 ml of xylocaine is injected lateral to the artery. This large quantity of local anaesthesia helps in stabilising the artery and to minimise local vasospasm.

DIRECT NEEDLE PUNCTURE + INJECTION OF CONTRAST WITH NEEDLE IN SITU For the Femoral Artery • Feel the inguinal ligament. • Feel the artery and fix it with three fingers of left hand below the inguinal ligament. • Inject the local anaesthetic agent at the site of the puncture as described above. • Make a hole in skin using a thick needle 2½ cm (1 inch) below the inguinal ligament or give a stab incision. Various anatomical descriptions are given regarding the site of puncture: • In the author's experience the best place is where the artery can be most easily palpated, irrespective of the relationship of this point to the inguinal skin crease. Since this is usually the point where the artery crosses the head of the femur it is also the easiest point to achieve haemostasis afterwards. • Introduce the needle through the skin hole maintaining an angle of 45 degrees to the skin surface and go along the course of artery. After traversing the subcutaneous tissue, feel the pulsations of the artery with the needle tip and puncture the artery with a sharp jab at 45 degrees to the skin surface and stop.

Angiography • 145

• If needle moves side to side it means that artery has not been punctured. Needle should move up and down to be quite certain about arterial puncture. • Remove the stillete and slowly withdraw the needle till blood freely spurts out. • To stabilise the needle, the needle is advanced about 1 to 2 cm into the vessel with the help of a short guide wire. • Connect the tubing to the hub of the needle through a 2 way stop cock making sure that there is no air inside it. • Suck and withdraw blood in the syringe and discard it and flush with another syringe. Then inject contrast and do filming. • Flush the system once every minute. The stopcock should be closed during flushing and not after stopping the injection to prevent reflux of blood into the needle tip where a thrombus may form. • Post procedure hemostasis is achieved by compression using 3 fingers; most distal finger on puncture site on the wall of the artery, other 2 fingers to compress the proximal vessel and pull out the needle. Do not allow spurting of blood after withdrawing needle if catheter is not used. Compress just enough till a bruit is felt on the finger and distal pulsations are just felt. Hold for 10 minutes, release in a graded manner (never leave suddenly as a thrombus may get washed away) and watch for rebleeding.

Complications of Direct Arterial Puncture Technique Using Needle 1. Due to local anaesthesia (a) Allergic (b) Toxic-due to injection in the vein, e.g., convulsions and cardiac arrhythmias. 2. Due to contrast media (a) Allergic and idiosyncratic reactions are much less common with intra arterial injections than with intravenous injections. (b) Feeling of warmth localised to the region supplied by the injected artery. (c) Pain may follow injection of contrast material into the vessel. (d) Chemotoxic effects: If contrast media containing pure sodium ions is used, the chances of these reactions are high. Meglumine salts are less toxic.

146 • Radiological Procedures

3. Due to technique (a) Haemorrhage/haematoma formation at puncture site. (b) Arterial thrombosis and embolization due to trauma to the vessel wall or if the puncture is made on an atherosclerotic plaque. (c) Sub intimal dissection. (d) Infection at puncture site (late). (e) Damage to local structures: For example, Brachia! plexus damage during axillary artery puncture.

4. Distant complications

(a) Peripheral embolism can result from atherosclerotic plaque damage or dislodgement of a thrombus formed at puncture site. (b) Air embolism can be prevented by : • ensuring that all taps and connectors are tight. • always sucking back when a new syringe is connected. • ensuring that all bubbles are excluded from the syringe before injecting. (c) Cotton fibre embolus occurs when syringes are filled from bowls containing cotton swabs. This can be prevented by : • Using separate bowls for flushing and for wet swabs. • A closed system of perfusion.

CATHETER ANGIOGRAPHY (Injection of contrast media with catheter in situ) Site of Entry 1. Femoral artery : Most common and preferred route of entry. 2. Axillary artery : Site of entry, in case of femorals are not palpable.

3. Brachial: Midarm is preferred for the catheterisation. Antecubital fossa is not the first choice because the artery is smaller than at the midarm. 4. Direct carotid : Percutaneous entry into the common carotid artery is done at the lower border of the thyroid cartilage. 5. Direct vertebral : Only historical now. The vertebral artery was punctured by a special needle which had only a side hole without any end hole. 6. Radial artery : The advantage is that if the artery is thrombosed

Angiography • 147

the limb still survives because of the palmar and dorsal arches. 4F or smaller caliber catheters have to be used. 7. Popliteal artery : This artery is punctured in the popliteal fossa and has been used primarily for angioplasty.

Seldinger Needle for Arterial Puncture • The classic Seldinger's needle is a 3 piece needle, outer one is the 16G cannula, middle is the needle with a lumen inside which is a stillete. • The length is 7 ems. This needle now is no longer in use. • The recent needle consists 2 parts, outer is the lumen (18 gauge) inside is the stillete (diameter more than 1 mm). • The needles of this type are modified COOK' s and modified POTT' s needles.

/ �

Technique for Catheter Angiography e

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Catheter

Cathete,

7 ( A

Damage and don't function properly. Backflow of blood is not prevented and pooling of blood stretches and balloons the walls

Fig. 24.2

Endovenous laser ablation indications • Insufficiency of the GSV or SSV visualized using CDUS (Colour Doppler Ultrasound). The superficial system has valves which prevent the backflow of the blood. However, when the valves become incompetent, the backflow starts and vessel becomes incompetent. Contraindications • Pregnancy • Peripheral Artery Disease • Allergies to Local Anesthetic Agents • Severe hypercoagulability • DVT or concomitant deep vein insufficiency

248 • Radiological Procedures

Mechanism of endovenous laser ablation Laser generators generally use a 600nm laser fiber to deliver the energy. Laser generates high-energy, bundled light that is monochromatic (same wavelength), coherent (in phase), and collimated (photons run parallel). The thermal reaction after the laser exposure is mechanism of action in laser treatment. The produced heat may reach up to 800 °C at the tip of the fiber and results in the formation of steam bubbles. The bubbles cause the blood to boil and induce thermal injuries to the venous endothelium. The intravascular heat decreases to 90 °C at 4mm from the laser tip. Steam bubbles that form at the tip of the fiber dissipate quickly and pose no systemic risk of tissue bums around the vein. Histological studies show that EVLA (endovenous laser ablation) damages the endothelial and intimal layers, the internal elastic lamina and the media to some degree. The adventitia is rarely affected. Using the pulse mode or continuous mode usually does not influence the effectiveness of the outcome. The major advantage of the continuous mode is that the duration of treatment is shorter. The pulse mode is considered to have a higher risk of adverse events such as microperforation.

Technique EVLA can be performed under local tumescent anesthesia in an outpatient setting. The most commonly used technique is to identify the vein using ultrasound from the ankle to the SFJ. The saphenous nerve is distant from the GSV above the knee compared to below the

Catheter entry point

Vein heated

Vein closed

Vericose veins

Laser turned off

turned on

Fig. 24.3: Endovenous laser treatment of vericose veins

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knee. Some radiologists prefer to cannulate the GSV at the level of the knee so as not to harm the saphenous nerve, which is prone to injury with ablations below the knee. Venous access is obtained by a needle puncture under ultrasound guidance. After entering the vein, a guide wire (mostly J tip or a straight tip) is inserted. If the varicose vein is tortuous, has a small diameter, has a large dilated branch emerging from it or contains thrombotic, sclerotic segments, advancing the wire can be difficult. In such case, under ultrasound examination of the area to visualize the tip of the wire, rotating the wire or exchanging the wire for a hydrophilic one usually solves the problem. After the guide wire is in place; the needle is removed, a small incision is made at the skin and a long introducer sheath is inserted. The tip of the sheath is located at the SFJ (sapheno-femoral junction), the laser fiber is inserted through the sheath so that the tip of the laser fiber is positioned 1-2 cm distal to the SFJ and 1-2 cm away from the tip of the plastic introducer sheath using ultrasound guidance. One should ensure that the laser tip lies beyond the end of the catheter before activating the laser energy. Local tumescent anesthesia (5 mL epinephrine, 5 mL bicarbonate and 35 mL 1 % lidocaine diluted in 500 mL saline or prilocaine 2% without bicarbonate, diluted in 500 mL saline) is then injected along the entire course of the saphenous vein from the cannulation site up to the SFJ. The tumescent anesthesia has three functions: 1. It protects the perivenous tissue from the effects of laser energy via a cooling effect. 2. It removes the blood from the lumen by collapsing the vein and increasing the effectiveness of the laser ablation. 3. It increases the surface area contact between laser tip and the vein wall.

Tumescent anaethesia surrounding laser fibre: The act of forcing the blood from the vein prior to ablation is important because it allows for ablation of the vein wall and does not cause a thrombosis within the lumen. The parameters used, including the power, the wavelength and the speed at which the laser fiber is pulled back are variable. Patients are usually discharged with an anti-inflammatory medication, such as diclofenac 50 mg taken three times daily for one or two weeks or as needed. Elastic bandages or class II (20-30 mmHg) graduated supporting stockings are recommended for one to three

250 • Radiological Procedures

weeks. Compressive stockings not only compress the vein and help to increase the effectiveness of the treatment, but they also decrease the patient's post-procedural discomfort.

Complications • Bruising, soreness, tenderness and indurations along the treated vein segment. • Mild post procedural pain. HIGH INTENSITY FOCUSSED ULTRASOUND (HIFU) High intensity focussed ultrasound is a non-invasive therapeutic technique for tissue ablation using focussed high intensity ultrasound waves. Traditionally, ultrasound has been used mainly for diagnostic purposes. HIFU is primarily used for treatment of certain tumors. Unlike cryoablation and radio-ablation, it is totally non invasive. History of development Fry and colleagues were the first to use HIFU in humans by producing elevated acoustic intensities. However, the use of HIFU in tumor treatment has come into picture more in 1990s with better understanding of its ability to cause cell necrosis. Difference between diagnostic ultrasound and HIFU • Diagnostic ultrasound works on low intensity ultrasound waves. However, HIFU works using high intensity ultrasound waves in the focus area of the probe. • The diagnostic ultrasound delivers time averaged intensity of approximately 1-100 mW/ crn.2 with peak pressure of 0.001-0.003MPa,however, intensity values in HIFU ranges around 100-10000 W/ crn.2 with peak pressure of 10-30MPa. Effects of HIFU and Principle of Working HIFU produces mainly 3 types of effects in tissues with variable role in tissue necrosis. 1. Thermal effects of HIFU Major effect in the tissues is heat energy production by the absorption of the ultrasound waves. The heat raises the temperature to around 60 degrees in the tissues and causes coagulation necrosis within few seconds. Since this effect is produced only in the region of focus point

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(where the rays converge), the superficial tissue survives the effects of HIFU as they don't receive focussed ultrasound waves. Focussing is done in small volume regions (e.g. 1mm diameter and length up to 6 mm). 2. Mechanical effects of HIFU Mechanical effects are due to ability of HIFU to interact with the matter causing rarefaction and compression. The various mechanical effects are as follows, • Cavitation - It is the formation or movement of gas filled bubble within the acoustic zone. It is because of the rarefaction and compression effect of HIFU that the gas is extracted from the tissues and bubble is formed. This bubble can interact with the acoustic field to produce the mechanical effects. There can be stable cavitation or inertial cavitation. In both types, there is change in the size of bubble in different ways producing pressure effect on surrounding tissues to damage them. • Micro streaming - It is the rapid movement of the fluid around the bubble created in cavitation (mainly stable cavitation). It can produce the shear effects to damage the tissue. This happens mainly in the liquid tissues. • Radiation Forces - These are produced due to reflection or absorption of ultrasound waves. The returned waves are of greater force and cause tissue damage. This happens mainly in the solid medium.

3. Biological Effect The mechanism involved in the biological effects of HIFU is mainly the thermal effects and the cavitation effects. What so-ever is the effect produced by HIFU, the mechanism of tissue damage is through cell necrosis and cell apoptosis. The intensity of HIFU and its effects do not follow the linear relation.

Clinical uses of HIFU • Treatment of benign and malignant solid tumours - It is mainly used in the treatment of HCC, renal cell carcinoma, bladder carcinoma and prostate cancer. • HIFU has been used in thrombolysis with variable success rate.. • Arterial occlusion for tumor therapy and bleeding. • Homeostasis for bleeding vessels and organs. • Drug and gene delivery.

252 • Radiological Procedures

Imaging guidance and monitoring of HIFU therapy Two important things control the success of HIFU therapy: • Whether focus of HIFU lies in region of interest. • Temperature monitoring. Monitoring can be done using MRI, sonography and CT scan. MRI offers distinct advantage of temperature monitoring which is not available in other modalities, however, it is expensive. USG provides better spatial resolution for location of target tissue but there is no temperature monitoring.

Limitations of HIFU • HIFU being ultrasound suffers from all of its major artifacts and drawbacks. E.g. acoustic shadowing, reverberation artifact etc. • Gas in the bowel cannot be penetrated by HIFU so less useful in bowel tumours. • In HIFU, the reflected waves are of very high energy so these can damage normal tissue between lesion and transducer. • HIFU is more useful where acoustic window is available. • HIFU can produce damage to surrounding normal tissues. • Shear effect can cause dissemination of malignant cells.

PERCUTANEOUS NEPHROSTOMY Introduction First described in 1955 by Goodwin et al as a minimally invasive treatment for urinary ob.struction causing marked hydronephrosis, Percutaneous nephrostomy (PCN) is a well-established therapy for urinary drainage in patients with supravesical urinary tract obstruction and for urinary diversion, as in patients with urinary fistulae, leaks or hemorrhagic cystitis. T he procedure is also performed to gain access to the urinary tract for ureteral stent placement, percutaneous stone removal and other endoscopic procedures. T he collecting system can be located with fluoroscopy or by using cross-sectional techniques such as ultrasonography or computed tomography. Fluoroscopic localization is especially useful if a radio-opaque stone, indwelling ureteral stent or contrast opacified collecting system can serve as a target.

Definition Percutaneous nephrostomy: Image-guided percutaneous placement of a catheter into the renal collecting system.

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Technical success for percutaneous nephrostomy: Placement of a catheter of sufficient size to provide adequate drainage of the collecting system or to allow successful tract dilatation so that the planned interventional procedure can be successfully completed through the nephrostomy tract. Indications and Contraindications A. Indications 1. Relief of urinary obstruction • Urosepsis or suspected infection. • Acute renal failure. • Intractable pain. 2. Urinary diversion • Traumatic or iatrogenic ureteral injury. • Inflammatory or malignant urinary fistula. 3. Access for end-urologic procedure • Stone removal. • Dilatation or stenting of a ureteral stricture. • Endopyelotomy. • Foreign body retrieval (e.g. fractured stent). • Ureteral occlusion for urinary fistula. • Tumor fulguration. • Delivery of medications and chemotherapy. • Biopsy of an urothelial lesion. 4. Diagnostic testing • Antegrade pyelography. • Ureteral perfusion (Whitaker test).

B. Absolute Contraindications:

• There are no absolute contraindications.

C. Relative Contraindications: • Uncorrectable severe coagulopathy or bleeding diathesis (e.g. thrombocytopenia, patient with liver or multisystem failure). • Terminally ill patient. • Fluoroscopically guided procedures are best avoided in pregnancy, particularly in the first trimester. Ultrasound guided procedures are preferred in such patients.

254 • Radiological Procedures

Anatomy relevant to percutaneous renal entry Renal anatomy is necessary for selection of safe route through the kidney for percutaneous nephrostomy. The renal artery divides into major ventral and dorsal branches, which creates ·a zone of relative avascularity between the divisions. This zone (known as the Brodel bloodless line of incision) lies just posterior to the lateral convex border of the kidney. Bleeding complications related to percutaneous nephrostomy can be minimized by traversing this avascular region.

Fig. 24.4: Avascular zone of Brodels

• The optimal entry plane lies posterolaterally at the junction of the anterior two-thirds and posterior one-third of the renal parenchyma. Because of the normal renal re:tation about its horizontal axis, the posterior calyces are usually oriented with their long axis pointing to this watershed territory. The anteriorly and posteriorly directed calyces can be identified fluoroscopically by using iodinated contrast material and air. • With the patient prone, urine containing iodinated contrast material opacifies anteriorly directed (dependent) calyces, which are usually seen tangentially. Air introduced into the collecting system accumulates in the posteriorly directed (non-dependent) calyces. Oblique fluoroscopy with the image intensifier angled 20°-30° from the vertical towards the side of the kidney to be punctured, can be used for entry into the collecting system, along the fluoroscopic axis. Alternatively, when vertical fluoroscopy

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is used, the patient may be placed in an oblique position with the side of the kidney to be punctured elevated to 20°-30 °.

Fig. 24.5: Urogram shows simultaneous opacification of anteriorly and posteriorly oriented calyces. Anteriorly directed calyces are seen tangentially and posteriorly directed calyces are seen en face due to the renal axis.

Puncture Site Selection The site of renal entry is dictated by the indication for access with consideration of the anatomic constraints. A lower pole posterior calyx accessed via a subcostal approach is usually best for simple urinary drainage. A posterior calyx of the upper or middle collecting system offers the easiest access to the uretero-pelvic junction for potential ureteral negotiation. A puncture behind a stone may be the most expedient for uncomplicated stone disease, whereas puncture of a posterior calyx in the upper pole (which may require a supracostal approach with a slightly increased frequency of complications) often provides the opportunity for visualization of a greater portion of the collecting system for removal of complex stones. In some difficult cases, a single access may not be sufficient and additional entry sites may need to be created (e.g., treatment of stag horn calculi). Basic Nephrostomy Technique Patient Preparation • Patient should be duly explained about the procedure and consent should be obtained.

256 • Radiological Procedures

• Patient should be screened for bleeding diathesis and any urinary infection. Prophylactic antibiotics should be given in case of any suspected infection. • Successful nephrostomy tube placement requires visualization of the collecting system for appropriate entry site selection. Fluoroscopic imaging after intravenous injection of iodinated contrast material is commonly used to locate the renal pelvis for puncture. In certain cases, opacification of the renal collecting system can be achieved by retrograde injection of contrast material via a ureteral stent. This method may be especially helpful in a patient with a non-dilated collecting system. Direct needle puncture can also be performed onto a visible stone or internal stent, if present. Direct antegrade needle pyelography performed from a posterior approach by using fluoroscopy and anatomic landmarks or with the assistance of other imaging guidance is the method most commonly used.

Standard Procedure for Initial Entry The patient is placed on the fluoroscopy table in the prone position. The back and flank are cleansed and draped under sterile conditions. An entry site into the collecting system is selected based on anatomic landmarks determined from prior imaging or by using other imaging techniques as previously outlined. After infiltration of the skin and subcutaneous tissues with 1 % lidocaine over the selected site, respiration is suspended and a 22- gauge needle is passed from a direct posterior approach into the collecting system during vertical postero-anterior fluoroscopy. During passage, two tactile "pops" can be appreciated. The first occurs as the needle traverses the renal capsule and the second occurs as the needle enters the collecting system. Renal entry is suggested by movement of the needle tip in concert with the renal outline during respiratory excursion. Aspiration is performed as the needle is withdrawn, until urine is observed. Contrast material and air are injected for calyceal definition. Some operators prefer carbon dioxide to air as a contrast material to avoid the unlikely possibility of air embolism. A point above the selected renal entry site is identified, ideally from a subcostal approach and lateral to the paraspinous musculature. A skin incision appropriate to the anticipated nephrostomy tube size is made with a no. 11 blade, taking care to avoid the neurovascular bundle beneath the inferior aspect of the adjacent rib. Under continuous fluoroscopy, an 18-gauge diamond-tipped needle is advanced along the axis of the fluoroscopy tube from the skin site to the selected renal entry site. After entry into the renal parenchyma, puncture of the selected calyx is monitored

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fluoroscopically. Only the posterolateral margin of the collecting system should be punctured. Through-and-through puncture of the anterior margin of the collecting system (and potentially the large anterior arterial branches) is to be avoided. The stylet of the needle is removed.

Track Dilation and Nephrostomy Tube Placement: Small-bore (up to 14F) tracks can be created over a guide wire coiled in the renal pelvis. Sequential dilation is performed over this guide wire. Tubes coated with hydrophilic material are usually easily placed through tracks dilated to an identical French size. At initial placement, a metal stiffening cannula is used to support the tube for passage through the soft tissues. The metal cannula, contained within the nephrostomy tube, is passed over the guide wire to a point just beyond the edge of the collecting system. The tube is advanced off the metal stiffener into the collecting system over the guide wire. Tubes of 8-10 F are usually sufficient for drainage of non-infected urine. Larger tubes (12-14 F) may be necessary for drainage of infected urine or to ensure appropriate urine flow in procedures complicated by gross hematuria. Once placed, the position of the catheter should be confirmed with an injection of contrast material with prompt decompression of the collecting system anticipated following optimal catheter positioning. Overdistension of the collecting system at initial

Air in posterior Calyx (a )

22G Needle

Wire

Wire

Drainage catherter

Wire (b)

(c)

( d)

(e)

Fig. 24.6: Radiographs show the basic technique of percutaneous nephrostomy.

(in different patients) (a) With the patient in the prone position, 22-gauge needle passed into renal pelvis. After a urine sample is collected, contrast material is injected to confirm the intrapelvic position and a small amount of room air is introduced to identify posteriorly directed calices. (b) From a 25 ° posterolateral oblique approach, a 18-20 g needle is passed into the pelvis (c) A wire passes easily into the ureter via the selected approach. (d) After dilation of track a self-retaining catheter (in this case a Cope loop catheter) is advanced over the wire, and the loop is formed in the renal pelvis

258 • Radiological Procedures

tube placement should be avoided, especially in patients with infected urine, to prevent bacteremia.

Post-operative Care • Frequent vital signs should be obtained to evaluate for the potential of ongoing blood loss or for the development of septic complications in those at risk. • Careful charting of the nephrostomy tube output to assess adequacy of drainage should also be performed. • Hematuria, which is initially present in virtually all patients in whom percutaneous renal entry is performed, should diminish gradually over 24--48 hours. • Narcotics may be required for pain relief, especially in patients with intercostal entries. • Arrangements should be made for ongoing tube care and maintenance if long-term drainage is anticipated. Complications 1. Septic shock 2. Hemorrhage 3. Bowel transgression 4. Pleural complications (pneumothorax, empyema, hydrothorax, hemothorax)

NON-INVASIVE TISSUE ABLATION THERAPY Non-invasive tissue ablation is a therapeutic technique of abnormal tissue destruction using different mediums. Tissue ablation can be done by 3 major ways: • Radiofrequency ablation. • Cryo-ablation. • High intensity focussed ultrasound ablation. Tissue ablation is mainly used to destroy tumour cells. Traditionally, surgery has been the mainstay treatment for the tumour resection. However, in recent times, tumour ablation has emerged as an important alternative as well as complementary treatment to the surgical approach. Need for ablation therapy: Traditionally, surgical resection has been the mainstay for tumour treatment where there is resection of normal tissue together with the abnormal tissue. However, with growing effort towards tissue sparing therapies, effort has been towards localised treatment. E.g. nephron

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sparing treatment in renal cell carcinoma. Ablation therapies have been a step in this direction. Initially, localised therapy has been given using open or laparoscopic route, however now percutaneous route has come into picture.

Cryo-Ablation Cryo-ablation is a technique of tissue destruction by creating very low temperatures.

Uses of Cryoablation

Cryo-ablation is used mainly in destruction of tumour tissue. It is commonly used where multiplicity of lesion with high chances of recurrence is there. It is also used in cases where need for organ sparing is required.

Principle and Technique Cryo-ablation causes rapid decrease in the temperature of the tissue and leads to ice formation at the target site. Two mechanisms work in causing cell death. Firstly, the ice formation with decrease in temperature is directly cytotoxic together with intracellular dehydration which causes rupture of cell membrane and death. Secondarily, there occurs clotting in the vessels when the temperature is reduced which causes cell death by hypoxia. Cryo-ablation is mediated through a cryoprobe which is generally a metallic shaft. Metallic shaft is inserted into the site of lesion. Further, the liquid gas like argon is used to rapidly cool the probe. This leads to ice ball formation around the probe. Cell death is time and temperature dependent. The critical temperature for the cell death ° ° ° is between -19 to -40 C. The probe itself reaches to around -19 C. The ice ball must extend 3 cm beyond the tumor margins for achieving ° a temperature of -20 C at the margins. Studies have shown that the double freezing cycle (i.e.-freezing-thawing-freezing) produces better efficacy. A variation in the normal single probe procedure is by using multiple probe cryoablation. The probes are available in various sizes (1.4-8 mm). The important aspect of cryoablation is intra-operative monitoring. It can be done through CT, MRI AND USG.

Risks of Cryo Ablation • Pain around the area of discomfort. • Risk of infection. • Bleeding. • If near liver, it can damage bile ducts and blood vessels. • In kidney, it can damage collecting system.

260 • Radiological Procedures

• In lungs, it can cause collapse with pneumothorax. • If near nerves, it can cause numbness and motor paralysis.

Radio frequency-ablation (RFA) Radio frequency ablation is a process of tissue destruction using high frequency alternating current. RFA is the most commonly used method of localised tissue ablation. It is mostly done through percutaneous route presently. Uses

• It is mainly used presently where surgical resection is not possible like in diffuse and recurrent tumours. • It is also used as a palliative treatment. • It is useful where normal tissue sparing is important for patient e.g. nephron sparing in person with solitary kidney.

Principle and Technique RFA works by using high frequency alternating current. This current produces a lot of heat energy at the site of application due to agitation of the ions around the electrode. This causes the coagulation necrosis of the tissue. It can cause damage to both normal and abnormal tissue. RFA can be done as an outpatient procedure with minimal hospital stay. It is generally combined with pre and post procedure imaging. E.g. CT to evaluate success of the procedure. The procedure is done using small electrodes which deliver the current to the site of interest. Needle can be placed under guidance of USG, MRI or CT. It can be done through the percutaneous, laparoscopic route or at laparotomy. With currently available devices, the largest focus of necrosis that can be induced with a single application is approximately 4-5 cm in greatest diameter. Thus, the diameter of suitable lesions must be less than 3- 4 cm unless placement of multiple probes is done. Simultaneous decrease of the arterial supply to the tumour with balloon occlusion or embolization or at laparotomy with temporary occlusion of the hepatic inflow (Pringle manoeuvre) increases necrosis. The proximity of the tumors to large vessels may prevent adequate heating, as well as proximity to central bile ducts, which predisposes the patient to a risk of biliary complications. RFA is commonly used for liver kidney and pancreatic tumours. COMPLICATIONS OF RFA: • Related to thermal effects: Surrounding normal tissue can be damaged. E.g. in hepatic tumour RFA, diaphragmatic damage, cholecystitis and bile strictures are common.

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• Related to electrode insertion: It can cause tumour seeding, infection, pneumothorax (in lung RFA), and haemorrhage. • Post ablation syndrome; flu like symptoms. • RFA can interfere w ith the functioning of other electronic devices in body. E.g. pacemakers, defibrillators. • RFA is a painful procedure so done under sedation and may suffer from complications of sedation.

REFERENCES HIFU 1. Kim Y, Rhim H, Choi MJ, Lim HK, Choi D. High-Intensity Focused Ultrasound Therapy: an Overview for Radiologists. Korean Journal of Radiology. 2008;9(4):291-302. doi:10.3348/kjr.2008.9.4.291. 2. Enne JW, Preusser T, Gunther M.Z; High-intensity focused ultrasound: principles, therapy guidance, simulations and applications; Med Phys. 2012 Dec; 22(4):311-22. Epub 2012 Aug 10. 3. Cheun VY.; Sonographically guided high-intensity focused ultrasound for the management of uterine fibroids; J Ultrasound Med. 2013 Aug; 32(8):1353-8. doi:10.7863/ultra.32.8.1353.

PCN 4. Siddiqi Nasir H, Percutaneous Nephrostomy Technique, Medscape, Nov 11, 2014 5. Regalado SP. Emergency Percutaneous Nephrostomy. Seminars in Interventional Radiology. 2006;23(3):287-294. doi:10.1055/s-2006-948768.

Non invasive tissue ablation

1. Foster RCB, Stavas JM. Bone and Soft Tissue Ablation. Seminars in lnterventional Radiology. 2014; 31(2):167-179. doi: 10.1055/s-00341373791. 2. Tatli Servet, Tapan -Omit,. Morrison Paul R, Silverman Stuart. G; Radiofrequency ablation: technique and clinical applications; Diagn Interv Radial 2012; 18:508-516.

Endovenous Laser ablation of Varicose Veins

1. Oguzkurt L. Endovenous laser ablation for the treatment of varicose veins.; Diagn Interv Radial. 2012 Jul-Aug; 18(4):417-22. doi: 10.4261/1305-3825.DIR.5248-ll.0. Epub 2011 Dec 28. Review. 2. Ash JL, Moore CJ. Laser treatment of varicose veins: order out of chaos; Semin Vase Surg. 2010 Jun; 23(2):101-6.

Chapter 25

CT Procedures • HRCT • CT Enteroclysis • CT Urography

HIGH RESOLUTION COMPUTED TOMOGRAPHY (HRCT) HRCT is the imaging technique where thin slice cuts are used with high-spatial-frequency reconstruction algorithm to view lung details and characterise the diseases. The term HRCT was coined by Toda. Nakata et al published first report on HRCT. Technical aspects HRCT has a role in evaluating fine details at the level of lung lobules, thus, separate factors are required. HRCT mediated fine details cannot be achieved in normal lung CT even after reconstruction. Technical aspects in HRCT can be divided into 2 parts -major and minor. Major factors 1. Slice thickness - HRCT is done using thin slice, of thickness less than 1 mm. Thin slice minimises volume averaging within the plane of scan. The normal slice thickness of 2.5-Scm is not adequate for HRCT. 2. Reconstruction algorithm- HRCT involves using high spatial frequency algorithm. This algorithm reduces image smoothening and increases spatial resolution making structures appear sharper. High spatial frequency simply means that frequency of information recorded in final image is relatively high. 3. HRCT has to be done in full inspiration with breath hold. Expiratory scans may lead to mis-interpretation. Important hints to confirm non inspiratory scans• Concave posterior margin of trachea hints at expiratory scan. • Gradient of increasing lung opacity from anterior to posterior hints towards expiratory scan.

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CT Procedures • 263

4. Expiratory scans have a role in obstructive airway diseases as they help in proving air trapping. 5. Role of prone imaging - It can be useful in confirming sub pleural pathologies e.g. Sub pleural reticulation.

Less Important Factors: • Kilovolts (Peak), Milliamperes and Scan Time High frequency algorithm increases noise together with increasing image details. These three parameters play an important role in minimising this noise. Noise is inversely related to the photons absorbed and to the product of milli-ampere and scan time. By increasing the mA/ kV and ms, noise can be minimised. However, these cannot be increased beyond a certain level as to avoid excessive exposure to radiation. The routine optimal values of kV (peak) are kept at 120 and mA at 100-200. Scan time is kept as short as possible (0.5-1 sec). • Window setting: One consistent lung window setting is important with window mean/width values of 600-700 HU/1000-1500 HU. Soft tissue window kept at 50/350 HU is used for mediastinum, hila and pleura. • Image display: Workstation of lung window 12 on 1. • Reconstruction: Trans-axial, entire thorax. • Matrix size is kept at 512x 512 with FOV encompassing entire thorax. Interslice gap is kept at 10-20 mm. Indications of HRCT • Evaluation of diffuse pulmonary disease discovered on chest radiographs, conventional CT of the chest or other CT examinations that include portions of the chest, including selection of the appropriate site for biopsy of diffuse lung disease. • Evaluation of the lungs in patients with clinically suspected pulmonary disorders with normal or equivocal chest radiographs. • Evaluation of suspected small and/or large airway disease. • Quantification of the extent of diffuse lung disease for evaluating effectiveness of treatment. Lung anatomy on HRCT Normal lung anatomy as well pathologies can be understood in terms of its basic unit, secondary pulmonary lobule.

264 • Radiological Procedures

Components of secondary pulmonary lobule: There are 3 components 1. Interlobular Septa Anatomically, secondary lobules are bounded by connective tissue septa which extend inward from pleural surface. The septa are part of peripheral interstitial fiber system. Interlobular septa are thicker in the periphery as compared to the central part of lung. The sepal thickness (0.1mm) lies at lower HRCT resolution limit, so septa are seen occasionally in the periphery. They contain lymphatics and veins. 2. Centrilobular Structures Central portion of the lobule contains pulmonary artery and its bronchiolar branches which supply the lobule and some connective tissues. In HRCT generally, a solitary dot is seen as bronchiole wall thickness is below resolution of HRCT. The pulmonary artery in the lobule can be seen as a dot like structure, branching or linear structure. 3. Lobular Parenchyma and Lung Acini Lobular parenchyma consists of alveoli and associated pulmonary bed. The parenchyma is supported by connective tissue stroma called intralobular interstitium. It is difficult to see these structures unless they have increased density than air. • Secondary lobules are well defined, regular with thicker and better defined interlobular septa. However, the lobules are irregular with thin interlobular septa in the central part. Normal Secondary Lobule Anatomy Bronchioles Pulmonary veins and Lymphatics

� Visceral Pleura

Fig. 25.1

CT Procedures • 265

CT ENTEROCLYSIS Definition. It is a hybrid technique that combines the methods of fluoroscopic intubation and infusion of fluid for examination of small­ bowel with CT. Indications 1. Partial small bowel obstruction. 2. Crohn's disease and Ulcerative colitis. 3. Suspected Meckel's diverticulum. 4. Malabsorption. 5. Small bowel tumors. 6. Unexplained gastrointestinal bleeding. 7. Complete colonic obstruction. 8. Paralytic ileus. 9. Massive small bowel dilatation. Contraindications 1. Pregnancy 2. Gastric outlet obstruction Technique CT Enteroclysis can be done in two ways1. CT enteroclysis with neutral enteral plus IV contrast. 2. CT enteroclysis with only enteral contrast agents. Patient Preparation These are common to both techniques, • Low residue diet and good hydration. • Laxatives a day prior to the procedure and no oral dose on the day of procedure. Sedation can be used optionally if required. CT Enteroclysis with Neutral Enteral plus IV contrast (using Neutral contrast agents) Fluoroscopic Phase • The various neutral enteral agents are methylcellulose, water or 0.1 % barium sulfate.

266 • Radiological Procedures

• 13F enteroclysis catheter is used with balloon positioned to the left of the spine in the horizontal part of duodenum. • 60 ml of air is infused under fluoroscopy following balloon inflation to check the position of the catheter. • 0.3mg of Glucagon is administered intravenously. • 1.SL of water is infused initially at the rate of 130 ml/min. • Patient is then shifted to the CT table.

CT Phase • 0.3 mg of Glucagon is administered intravenously. • 150L of water is infused at the rate of 100-150 ml/min. • I/V contrast agents are administered at 4 ml/sec (total 150 ml). CT is obtained at a delay of 50sec for optimal mucosal enhancement. • Balloon is deflated and refluxed water from stomach is aspirated. • These agents allow better assessment of mucosal enhancement, mural thickness as well as mesenteric vasculature. • Better used in unexplained sub acute gastrointestinal bleeding due to vascular malformation and assessment of inflammatory activity and complications of small bowel Crohn's disease. CT Enterodysis with Enteral contrast agents (using Positive contrast agents) Fluoroscopic Phase • 13-14F enteroclysis catheter is used with balloon positioned in the descending part of duodenum. • 60 ml of air is infused under fluoroscopy following balloon inflation to check the position of the catheter. • 12% of the water soluble contrast agent (total> 2 Ltrs) is infused in the small intestine at the rate of 55-100 ml/min. CT Phase • 550-1000 ml of water soluble contrast material is infused on CT table before and during CT examination.

Fig. 25.2: Enteroclysis Catheter

CT Procedures • 267

• Enteroclysis tube is withdrawn from the stomach and contrast material is suctioned. • No intravenous contrast is used with these agents. • Mainly used to detect lower grades of small bowel obstruction and internal fistulas.

Disadvantages 1. Increased cost and increased radiation dose. 2. Long timing of procedure. 3. The invasiveness of the procedure raises concern for complications such as bowel perforation, enteral contrast material aspiration or respiratory depression from sedation.

CT Enteroclysis versus MR Enteroclysis

• Magnetic resonance (MR) enteroclysis has the advantage of lack of radiation exposure and safe contrast agents but appears less accurate than CT enteroclysis. • In patients allergic to iodinated contrast, MRI is used. • In patients with impaired renal function, MRI is used. • Direct evaluation of diseased wall, extension and involvement to other abdominal structures are well delineated. • Small bowel lesions of pelvis are easier to detect. • Large bowel is simultaneously evaluated.

COMPUTED TOMOGRAPHIC UROGRAPHY Intravenous Urography (IVU) has been traditionally used as an imaging modality of choice to evaluate the urinary tract. However, with the introduction of multidetector technology, Computed Tomographic Urography (CTU) has been preferred in imaging the urinary tract. CT urography is temporal and spatial evaluation of the urinary tract involving non contrast phase and post contrast multiphase examination (cortico-medullary, nephrogenic and excretory phases). CTU offers the advantage of imaging the urinary tract in a single breath hold along with image reconstruction. Indications Conditions commonly referred for CTU: 1. Urinary calculus disease 2. Evaluation of Hematuria

268 • Radiological Procedures

3. 4. 5. 6.

Suspected pelvis or ureteral obstruction Inflammatory conditions of kidney and ureter Congenital anomalies of kidney and ureter Urinary tract trauma

Contraindications The patients in whom this procedure is contraindicated are as follows: 1. Allergy to contrast agents. 2. Asthmatic patients. 3. Patients with cardiac diseases. 4. Renal insufficiency. 5. Diabetic patients. 6. Pregnant patients. Procedure Most CTU protocols are triphasic examinations. Oral contrast is not required. Patient Preparation: Patients should be told to avoid food intake 6 hours before the examination. However, they should maintain good hydration prior to the examination. Technique: Patient is made to lie supine with arms over the head. CTU is performed by adjusting a tube voltage of 120kVp and a tube current of 250mAs, with a pitch of 1.5:1 and collimation of 2.5mm. Non contrast images are obtained with a slice thickness of 5mm and contrast enhanced images are obtained with a slice thickness of 3mm. After the scan has been completed, the images are reconstructed as required. Imaging Protocol: A typical protocol consists of the following: (a) Non-contrast (b) Contrast enhanced - Cortico-medullary - Nephrographic - Excretory or delayed Unenhanced scans exten­ ding from the top of the Cortico-rnedullary kidneys through the bladder

CT Procedures • 269

Nephrographic Phase

Excretory Phase

are useful for evaluation of calculi, fat containing lesions and parenchymal calcifications and to provide baseline attenuation for assessment of lesion enhancement. For contrast enhanced images, a non-ionic iodinated contrast agent (containing 30-42 g of iodine) is administered intravenously at a dose of 100-150 ml at the rate of 2-4 ml/ sec. Cortico-medullary phase images are obtained 30-70 seconds after start of contrast administration, which provide information about the renal vasculature and perfusion. Nephrographic phase images obtained after 90-180 seconds are sensitive for characterization and detection of renal masses. Homogeneous enhancement of the kidneys during this phase optimizes detection of small renal masses. Excretory phase images are obtained 8-lOminutes after contrast administration when there is opacification of the collecting systems, ureters and bladder. Excretory images allow for evaluation of the urothelium.

SPLIT BOLUS TECHNIQUE CT Urography can also be performed by the Split bolus technique, whereby the contrast is given as 2 boluses before a single enhanced scan is acquired. With this technique, after the unenhanced CT scan, a fractionated dose of contrast material (30-S0mL) is administered followed by a delay of 8-10 minutes before the remaining (80-100 mL) contrast material is given. A subsequent scan is obtained 100 seconds after the second dose of contrast material. The earlier smaller bolus provides excretory information, while the second, larger bolus provides information on vascular anatomy and renal parenchyma.

270 • Radiological Procedures

Disadvantages 1. Sub-optimal opacification of the ureters and intermittent peristaltic waves may result in limited visualization of one or more segments. 2. High radiation exposure. 3. Expensive procedure. A variety of techniques have been proposed to achieve adequate opacification and distension of the pelvicalyceal system and ureters. These are, • abdominal compression • saline infusion • diuretic administration • prone patient positioning However, compression is not recommended in patients with abdominal pain or in patients with history of urinary tract obstruction, recent surgery and aortic aneurysm. To limit radiation dose, upper abdomen superior to the kidneys is excluded during unenhanced and excretory acquisitions. The split bolus technique has the advantage of elimination of an additional acquisition resulting in decreased radiation dose. Also, radiation reduction techniques such as automated current modulation can be helpful to limit overexposure.

REFERENCES 1. Lalitha P, Reddy MCh, Reddy KJ, Kumari MV. CT Enteroclysis; Jpn J Radiol. 2011 Dec; 29(10):673-81. Epub 2011 Oct 19. 2. van der Merwe BSl, Ackermann C, Els H; CT enteroclysis in the developing world: how we do it, and the pathology we see; Eur J Radiol. 2013 Aug;82(8):e317-25. doi: 10.1016/j.ejrad.2013.03.018. Epub ?013 May 8. 3. Sundaram B, Chughtai AR, Kazerooni EA; Multidetector high­ resolution computed tomography of the lungs: protocols and applications; J Thorac Imaging. 2010 May; 25(2):125-41. doi:10.1097/ RTI.0b013e3181d9ca37. 4. ACT-STR P ractice parameter for the performance of highresolution computed tomography (HRCT) of the lungs of adults; ACR, revised 2015. 5. Silverman G. Stuart, Leyendecker R. John and Amis Stephens E. What Is The Current Role of CT Urography and MR Urography in the Evaluation of the Urinary Tract? Radiology 2009; 250 309-323

CT Procedures • 271

6. Alderson M. Skip, Susan Hilton, Papanicoloau Nicholas. CT Urography: Review of Technique and Specrum of Diseases. Applied Radiology. 2011; 40: 6-13. 7. O'Connor J.Owen, Maher M. Michael. CT Urography. AJR 2010; 195 : 5. 8. Joffe A. Sander, Servaes Sabah, Okon Stephen, Horowitz Mitchell. Multidetector Row CT Urography in the Evaluation of Haematuria. Radiographies 2003; 23 : 1441-1455. 9. Kawashima Akira et al. CT Urography. Radiographies 2004; 24 : S35-S54. 10. [Guideline] ACR Practice Guideline for the Performance of Excretory Urography, Accessed December 14 2010 11. Wang LJ, Wong YC, Huang CC, Wu CH, Hung SC, Chen HW. Multidetector computerized tomography urography is more accurate than excretory urography for diagnosing transitional cell carcinoma of the upper urinary tract in adults with hematuria. J Ural. Jan 2010;183(1):48-55. 12. Katayama H, Yamaguchi K, Kozuka T, Takashima T, Seez P, Matsura K. Adverse reactions to ionic and nonionic contrast media. A report from the Japanese Committee on the Safety of Contrast Media. Radiology. Jun 1990; 175(3) : 621-8.

Chapter 26

MR Procedures 1. • MR Arthrography 2. MRCP Magnetic Resonance Cholangio - Pancreatography • Shoulder Arthrography • Technique • MRI Protocol in Arthrography • Clinical applications • Knee Arthrography • Pitfalls in interpretations • Wrist Arthrography • Recent advances comparision with ERCP

MR ARTHROGRAPHY MR arthrography is a semi-invasive imaging technique used to evaluate the intracapsular part of joint with the help of capsular distension using contrast agents. History of Arthrography Intracapsular contrast injection and imaging have undergone several developments over a period of time. In earlier days, pneumoathrograms were done where air was used to distend the joint capsule. It was later replaced by positive contrast based joint athrography. With further development, double contrast based arthrography came into use where both air and positive contrast agents were used to evaluate the joint but in lower amounts. However, in the present time, the most commonly used agent is gadolinium dimeglumine in mixture with normal saline or positive contrast agent. MRI is the modality used in viewing the details after contrast injection. Joints for MR Arthrography MR arthrography is mainly done in the synovial joints. Major joints where MR arthrography is done are, • Shoulder(gleno-hurneral joint) • Knee joint • Ankle joint • Wrist joint • Temporo-mandibular joint

272

MR Procedures• 273

MR ARTHROGRAPHY SHOULDER JOINT Indications • To evaluate the articular cartilage. • To evaluate the biceps-labral complex. • To evaluate capsular ligamentous complex.

Contraindications • Infection over the superficial tissue.

Technique MR Arthrography includes contrast injection into the joint capsule followed by MRI. It can be done using direct or indirect approach. Indirect approach includes intravenous injection of the contrast. It is more useful for synovial evaluation. Direct approach includes direct injection of contrast into the joint space. It is the preferred approach for evaluation. MR arthrography can be done as an isolated procedure or it can be combined with plain MRI images prior to the contrast injection.

Preparation of the Contrast Agent Different contrast mixture combinations are used for injection. However, most commonly used combination consists of the following• Iodinated contrast agent: 5 ml • Anaesthetic agent : 10 ml • Normal saline: 5 ml • Gadopentatae dimeglumine: 0.1-0.2 ml

How to inject the contrast: Contrast can be injected under fluoroscopic or ultrasound guidance. It helps in correct placement of the needle tip into the joint space which in turn prevents the extracapsular spillage. The contrast can be injected using the anterior or the posterior approach. The anterior approach is generally preferred. • The patient is placed in the supine position on the fluoroscopic table with the arm externally rotated. • The shoulder is prepared under aseptic conditions. • The injection site is localised over the medial margin of the humeral head at the junction of upper two-thirds and lower one-third.

274 • Radiological Procedures

• Local anaesthetic agent is injected into the superficial tissues. • Needle is placed into the joint space and confirmed fluoroscopically. • Contrast is injected into the joint space. • The MRI is done within one hour of contrast injection. Posterior approach can also be used in selective cases where distortion of the anterior anatomy is to be avoided.

MRI .PROTOCOL IN MR ARTHROGRAPHY Various sequences taken are• Plain Scout in different planes. • Sagittal Oblique Tl WI with fat Suppression. • Coronal Oblique Tl WI with fat Suppression. • Axial Oblique Tl WI with fat Suppression. • Coronal PD Image. • Coronal T2WI with fat Suppression. Common labral injuries• Bankart's lesion • Perthe's lesion • ALPSA • GLAD • Reverse Bankart's lesion • Kim's lesion MR arthrography can be helpful in assessing the gleno-humeral ligaments and capsule status.

Fig. 26.1: Mr arthrography sagittal image

showing normal gleno-humeral ligaments

MR Procedures• 275

MR ARTHROGRAPHY KNEE JOINT Indications

• Evaluation of recurrent meniscal injuries. • Osteo-chondral injuries. • Articular loose bodies.

Technique

Different approaches can be used for contrast injection. However, lateral approach is the most commonly used. 1. Patient is positioned over the table with the fluoroscopic tube over the patella. 2. Mid-portion of the patella is palpated. 3. Patient is asked to relax the quadriceps and sublux the patella laterally. The posterior edge of the lateral margin is palpated and the mid-portion is marked. 4. Standard sterile conditions should be followed. 5. Anaesthetize the skin. 6. Advance a 1½" 25G needle under the patella from a lateral approach while subluxing it laterally. The needle should come to rest against the patellar cartilage near the centre of the patella. 7. Contrast solution is injected taking care not to inject bubbles. 8. The contrast solution should flow easily. This can be monitored fluoroscopically. Some experienced individuals routinely perform this procedure without fluoroscopic guidance.

Contrast Solution

1. Inject 40 cc standard MR Arthrogram diluted gadolinium solution (20 cc normal saline, 10 cc Omnipaque 300, 10 cc 1% lidocaine, and 1.0 cc gadolinium). 2. If the patient has a joint effusion, aspirate off as much as possible and inject the above 40 cc plus whatever volume was aspirated.

MR ARTHROGRAPHY WRIST /HAND

It can be done by 2 ways: • Direct MR Arthrography. • Indirect MR Arthrography. Direct is more useful. • Patient is positioned in supine position with hand on side and palm facing downwards.

276 • Radiological Procedures

• The wrist is prepared under aseptic conditions. • The entry site is subjected to local anaesthesia. • The radio-carpal joint is entered dorsally using 25G needle with the needle directed proximally to avoid dorsal lip of radius. • Injection into the intercarpal and distal radio-ulnar joints is done. • Multiple injection sites can be chosen as per requirement. • A total of 3-4 ml contrast mixture is injected. • Patient is then shifted to MRI gantry for imaging using standard protocol.

MAGNETIC RESONANCE CHOLANGIO­ PANCREATOGRAPHY (MRCP) • Technique • Clinical Applications • Pitfalls in interpretation • Recent advances • Comparision of MRCP vs ERCP. Magnetic Resonance Cholangio-Pancreatography (MRCP) is used for non-invasive work-up of patients with pancreatico-biliary diseases. Technique Preparation: Patient should be empty stomach for 8-12 hours to avoid any fluid in GI tract especially in stomach. If fluid is present in stomach, it can be suppressed by intake of blue-berry juice. MRCP is usually performed with heavily T2-weighted sequences by using fast spin-echo or single-shot fast spin-echo software and both thick collimation (single-seciton) and thin-collimation (multi-section) techniques with a torso phased array coil. The coronal plane is used to provide a cholangiographic display and the axial plane is used to evaluate the pancreatic duct and distal common bile duct. 3-D reconstruction can be done by using a maximum-intensity projection (MIP) algorithm on the thin-collimation source image. Although the thick-collimation and 3-D MIP images more closely resemble conventional cholangiograms and are familiar to may clinicians, spatial resolution is degraded because of volume-averaging effects. A number of techniques have been employed to achieve heavy T2weighting, however, two techniques commonly used include-RARE and HASTE. RARE: Rapid Acquisition and Relaxation Enhancement (RARE) is

MR Procedures • 277

a fast spin echo (FSE) or Turbo spin echo (TSE) single shot technique acquired as thick slab of 3-7 centimetres with acquisition time of 2-3 seconds. RARE uses long TE in the range of 900 ms so that fluid which has long T2 shows bright signal. Signal from background is decayed. RARE is generally acquired as thin slice acquisition for small intraductal calculi or other filling defects. HASTE: Half Fourier Single Shot Turbo Spin Echo (HASTE) is FSE or TSE acquired as single shot in which only half of K-space is filled. TE used in HASTE is in the range of 80-100 ms so background tissues are not suppressed. Post processing in the form of MIP is needed to get cholangiopancreatogram. MRCP should also include, depending on the case, other MR sequences to evaluate extraductal structures and pathologies.

Clinical Applications of MRCP 1. Cystic Diseases of the Bile duct: Choledochal cyst, Choledochocele and Caroli's disease. 2. Congenital Anomalies: • Pancreatic divisum - MRCP is useful in detecting pancreatic divisum. Congenital variations like low cystic duct insertion, medial cystic duct insertion, parallel course fo the cytic and hepatic ducts and aberrant right hepatic duct are visualised on MRCP. • Biliary atresia - MRCP can non-invasively establish the diagnosis of biliary atresia. 3. Choledocholithiasis: MRCP is an excellent method to detect CBD stones. They appear as dark filling defects within the high-signal-intensity fluid on MRCP. 4. Primary Sclerosing Cholangitis: Findings on MRCP include(i) String-on-beads appearance/Pruned-tree appearance. (ii) Pruning of peripheral ducts. (iii) Thickned duct wall. (iv) Intraluminal web. (v) Obtuse angle between central and peripheral ducts (Normally angle is acute). 5. Post-surgical Complications: Post-surgical complications like benign strictures, retained stones,

278 • Radiological Procedures

biliary leak and biliary fistula are effectively evaluated with MRCP. 6. Chronic Pancreatitis: Findings in alcoholic pancreatitis include(i) Irregular/beaded enlargement of pancreatic duct. (ii) String of pearls appearance. (iii) Intraductal filling defect due to calculi/protein plugs. (iv) Loss of normal tapering of main pancreatic duct. (v) Stenosis of MPD is shorter, smoother and more symmetrical in chronic pancreatitis. 7. Pancreatic pseudocysts: MRCP is more sensitive than ERCP in detection of pseudocysts. However, MRCP is less sensitive in demonstrating the site of communicaiton with the pancreatic duct. 8. Neoplastic Lesions: Features of malignant stricture in CBD(i) Short segment stricture with irregular margin. (ii) Asymmetrical narrowing. (iii) Rat tail appearance. (iv) Stricture with shouldering. (v) Ductal encasement with lymph node enlargement. 9. Biliary Cystadenoma and Cystadenocarcinoma: ERCP has a limited role in demonstrating the presence and extent of disease because the mucin secreted by these tumors causes filling defects and partial obstruction of contrast material. MRCP is potentially more accurate in demonstrating the extent of these tumors. Pitfalls in interpretation 1. Filling defect: Pneumobilia, blood clot, sludge and susceptibility artifacts from metallic clips may be misinterpreted as small stones. 2. Non pathological bile duct narrowing from vascular pulsation (Hepatic artery & Gastroduodenal artery): Most common sites are common hepatic duct, left hepatic duct and mid portion of CBD. 3. Misinterpretation Related to the Cystic Duct: When the cystic duct runs parallel to the common hepatic duct for some distance, the two structures together may be mistaken for a dilated common bile duct. This pitfall is most likely to occur on an MIP reconstructed image. Therefore, the source images should be evaluated carefully.

MR Procedures • 279

4. Pitfalls Related to the Peri-ampullary Region: Contraction of the choledochal sphincter may be misinterpreted as an impacted stone or stricture in the distal bile duct. When this defect is seen on direct cholangiography, it is known as the pseudocalculus sign. Unlike with an impacted stone, only the superior margin of the defect is outlined by the high-signal intensity bile. A more important difference is that the presence of the defect is transient.

Recent advances in MRCP (1) Functional/Contrast Enhanced MRCP

Although conventional fluid-based T2-weighted MRCP is excellent for demonstrating morphological details, there is still pack of functional information concerning bile production and excretion through the biliary tree. MR contrast agents with hepatobiliary excretion such as mangafodipir strisodium, gadopentate dimeglumine or Gd-BOPtA are now being used for this purpose. The optimum timing for biliary excretion of these contrast agents ranges from 10-60 minutes. The preferred acquisition sequence for Tl-weighted MRCP is a fat-saturated, spoiled gradient recall (SPGR) sequence. Indications and current role of Functional/Contrast Enhanced MRCP: 1. Defining biliary anatomy for pre-surgical planning prior to major hepatectomies and living donor liver transplantation. 2. Evaluating integrity of bile ducts. 3. Differentiating true obstruction from pseudo-obstruction.

(2) Secretin - f.jfhanced MRCP Secretin is a gastrointestinal peptide which stimulates pancreatic duct epithelial cells to produce a bicarbonate rich fluid with resultant increase in diameter of pancreatic duct. It also increases the tone of sphincter of Oddi with increase in volume of stationary fluid within the duct. The adverse effects of secretin are mainly nausea, flushing, abdominal pain, and vomiting which can be seen in up to 5% of patients. Advantages 1. Better delineation of full length of main pancreatic duct. 2. Enhances detection of pancreatic variations such as pancreatic divisum. 3. Reduces frequency of false positive findings of stricture. 4. Assess sphincter of Oddi function.

280 • Radiological Procedures

r��;;-

Comparison of MRCP and ERCP

I

--

MRCP

invasive, radiation-

1MRc P produces images of ducts in their natural physiological state. 1 3. MRc·P can be combined with conventional MR imaging to evaluate I extraductal disease. s beyond obstruction e visualized.

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Involves contrast injection and radiation. -ERCP, ducts are distended with ontrast.

Extraductal pathology or structures cannot be assessed.

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MRCP can be performed in post surgical patients in whom biliary-enteric anastomosis has been performed 6. Non-operator dependent. 7. MRCP is useful in patients after incomplete ERCP. or unsuccessful _ 8. I Safe. 5.

l:

ERCP

I

Contrast may not pass beyond the obstruction. Hence, proximal ducts are not seen. It may not be possible technically to perform ERCP in such patients. Operator dependent. Upto 10% technical failures are reported in ERCP.

ERCP involves morbidity and mortality. Complications include pancreatitis, haemorrhage, perforation and sepsis. Therapeutic options like 9. Major limitation of MRCP is its therapeutic sphincterotomy, endoscopic incapability. lithotomy, brush cytology, collection of pancreatic juice, stricture dilatation, stent placement and biopsy are possible with ERCP. 10. Second limitation of High spatial resolution achievable MRCP is its lesser spatial with ERCP may be important in resolution as compared precise delineation of pancreatic to ERCP. side branches. This is of significance with availability of newer less invasive pancreatic surgeriessegmental pancreatic resection, cyst enucleation. -

L

L

MR Procedures • 281

REFERENCES

1. Chung, C. B., Gigena, L.M. and Resnick, D. 2002. MR Arthrography of Shoulder. Current Protocols in Magnetic Resonance Imaging. A:A22:A22.2. 2. Ogul H, Bayraktutan U, Yildirim OS, et al. Magnetic Resonance ARthrography of the Glenohumeral Joint: Ultrasonography-Guided Technique Using a Posterior Approach. T he Eurasian Journal of Medicine. 2012; 44(2):73-78. doi: 10.5152/eajm.2012.18. 3. Lee MJ, Motamedi K, Chow K, Seeger LL. Gradient-recalled echo sequences in direct shoulder MR arthrography for evaluating the labrum. Skeletal Radiol. 2008;37:19-25. 4. Choudur HN, Ellins ML. Ultrasound-guided gadolinium joint injections for magnetic resonance arthrography. J Clin Ultrasound. 2011; 39:6-11. 5. MR Cholangiopancreatography of Bile and Pancreatic Duct Abnormalities with Emphasis on the Single-Shot Fast Spin-Echo Technique, RadioGraphics 2000; 20:939-957. 6. Fulcher AS, Turner MA. MR pancreatography: a useful tool for evaluating pancreatic disorder. RadioGraphics 1999; 19:5-24. 7. Ernst 0, Asselah T, Sergent G et al. MR Cholangiography in primary sclerosing cholangitis. AJR Am J Roentgenol 1998; 171:1027-1030. 8. Pitfalls in MR Cholangiopancreatographic Interpretation. RadioGraphic 2001; 21:23-37. 9. Advances in magnetic resonance cholangiopancreatography: From morphology to functional imaging. Indian J Radiol Imaging/ November 2007/Vol. 17/Issue 4.

Cha ter 27

Positron Emission Tomography (PET) • • • • •

Principle of PET Interpretation Fusion with CT & MRl Uses of PET Limitation of PET

Positron em.Iss1on tomography is a diagnostic imaging technique which evaluates the metabolic activity in any tissue using radiotracers to isolate high activity zones (physiological or pathological) from low activity zones. Traditionally, PET was used alone to give high activity zone, however, it suffered major drawback of organ localisation. Hence, recently PET has been used in combination with CT (PET CT) or MRI (PET MRI).

Principle of Pet PET is a functional imaging technique which locates the high functional zones in body, physiological or pathological (malignant tumors). A high activity zone in the body has increased glucose uptake and metabolism. In malignant tumors which have fast growth rate and division, requiring more glucose and amino acids. PET scan uses radio tracers based on these compounds to judge the metabolic activity. Most commonly used radiotracers are the glucose based compounds e.g. FDG (F-fluro-2-deoxy-D-glocose). Cells with increased metabolism show increased uptake of FDG. FDG enters into metabolism cycle and is converted into FDG-6-phosphate by hexokinase enzyme. However, the further enzymes cannot metabolise phosphorylated glucose which gets trapped within the cell. The trapped FDG releases positrons which combines electrons from the surroundings and undergoes annihilation. This process releases ° two photons moving at approximately 180 to each other. These positrons are detected by scintillators and then data is interpreted.

282

Positron Emission Tomography (PET) • 283

Detection of Emission The emissions in PET consist of high energy photons (512 KeV). These photons are detected using high power scintillators. Most common scintillators are made of bismuth germinate (BGO) or cerium- doped lutetium oxyortho silicate (LSO). These scintillators are further coupled with photo multiplier tubes (PMT).

Interpretation The interpretation of the radiotracer activity can be assessed using qualitative and quantitative methods. However, before interpretation, the values need to be corrected for the attenuation they suffer because of passage through the body. Qualitative method: It is based on the visual impression of the uptake based on the provided images. Intensity of the colour in comparison to the surrounding helps to differentiate normal from abnormal. However, it is highly subjective. Quantitative methods: These are the semi-quantitative values given by the software. Standard uptake value: It is defined as tracer activity in the tissues divided by injected radiotracer dose/patient weight where radiotracer dose is in milli-curie and patient weight is in kilograms. The SUV value cut -off to differentiate benign from the malignant is 2.5-3. However, it is important to differentiate between normal physiological uptake and pathological values. The other less commonly used methods are glucose metabolic rate, tumour burden.

Pet Fusion with CT and MRI PET was used in isolation initially to evaluate the lesions. However, PET suffered a major drawback of lesion localisation with respect to body parts. This lead to the simultaneous use of PET with CT and MRI. Presently, the hybrid PET and CT scanners are mostly used where both PET and CT are first done separately and then interlinked in different planes. MRI fusion with PET is still in the experimental stage.

Uses of PET/PET-CT Most common use of PET scan is in oncology.

284 • Radiological Procedures

DIAGNOSIS • PET is the modality of choice in characterising of lung nodules especially less than 10 mm. • PET is very helpful in locating the primary tumour where multiple secondaries exist. • PET is useful in breast cancer, thymic tumours. • However, the FDG -PET has limited application in brain tumours due to inherent high uptake of glucose in brain tissue. Initial Staging PET has role in the initial staging of the tumours as it is helpful in localisation of the metastasis in the distant sites and has an impact on the treatment. In lung cancers, it is mainly used in non-small cell cancers. PET can better determine the staging in comparison to contrast enhanced CT. However, certain tumours like mucinuous adeno-carcinoma are not FDG avid so can give false negative results. Treatment Response Most of the drugs used in chemotherapy are cytostatic and not cytocidal, so do not produce much change in the size of the tumour, however, there is decrease in the metabolic activity of the cells. This leads to decreased glucose utilisation by the cells. This makes PET as the modality of choice to judge the initial response to therapy as compared to other modalities like contrast enhanced CT. However, there is not much difference in the end stage evaluation for treatment. It is very useful to separate the responders from non-responders after 2 cycles of chemotherapy in lymphoma. Restaging/Recurrence/Prognosis Many cancers re-occur after the initial treatment. This is one of the most acceptable indications of PET CT. PET has a proven role in assessing the prognosis of colorectal carcinoma. Limitations of PET • Patient motion can interfere with the site localisation. • Attenuation (transmission) corrections artifacts can occur where there are highly attenuating objects in the path of the CT beam, such as hip prostheses, pacemakers, dental devices and contrast­ enhanced vessels.

Positron Emission Tomography (PET) • 285

• If the patient has undergone strenuous activity, false positive results can come due to increased FDG uptake by the muscles. • PET does not differentiate between physiological and pathological uptake areas. • PET can show enhancement even in non tumourous lesions like infections, etc.

The new edition of "Radiological Procedures" has been thoroughly revised and updated in simple and lucid language. The new methods and tools that are now available in the field of radiology for the diagnosis of disease conditions have been added. Several chapters reflect the rapid pace of advancement in the field of radiology and the book concludes. with a series of chapters that summarizes the newer trends in radiography, CT, MR guided procedures & PET scan. The book has been written keeping in mind the basic requirements for both radiologists & radiographers. This book will enlighten students and contribute to a healthier future.

Dr. Bhushan N Lakhkar, is a well known faculty in the field of Radiodiagnosis. He has a teaching experience of over 35 years in various teaching institutions in India and Abroad. He was Professor and H.O.D. at KMC, Manipal for 15 years. He was a visiting professor at Agakhan University, Nairobi. He is an author of two books in radiodiagnosis. He has many publications to his credit in national and international scientific journals. He is very popular amongst the students for his innovative approach and simple method of teaching. During his distinguished career he has been recognized for his academic excellence by learned authorities.

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