COMPUTED TOMOGRAPHY OF THE RETROPERITONEUM SERIES IN RADIOLOGY J. Odo Op den Orth, The Standard Biphasic-Contrast Examination of the Stomach and Duodenum: Method, Results and Radiological Atlas. 1979. ISBN 90 247 2159 8 J.L. SelIink and R.E. Miller, Radiology of the Small Bowel. Modern Enteroclysis Technique and Atlas. 1981. ISBN 90 247 2460 0 R.E. Miller and J. Skucas, The Radiological Examination of the Colon. Practical Diagnosis. 1983. ISBN 9024726662 S. Forgacs, Bones and Joints in Diabetes Melitus. 1982. ISBN 90 247 2395 7 G. Nemeth and H. Kuttig, Isodose Atlas. For use in Radiotherapy. 1981. ISBN 9024724767 J. Chermet, Atlas of Phlebography of the Lower Limbs, including the Iliac Veins. 1982. ISBN 90247 2525 9 B. Janevski, Angiography of the Upper Extremity 1982. ISBN 90 247 2684 0 M.A.M. Feldberg, Computed tomography of the retroperitoneum. An anatomical and pathological atlas with emphasis on the fascial planes. 1983. ISBN 0 89838 573 3 CO~UTEDTOMOGRAPHYOFTHE RETROPERITONEUM An anatomical and pathological atlas with emphasis on the fascial planes MICHIEL A.M. FELDBERG, M.D. Department of Radiodiagnosis Utrecht University Hospital Utrecht The Netherlands 1983 MARTINUS NIJHOFF PUBLISHERS a member of the KLUWER ACADEMIC PUBLISHERS GROUP BOSTON / THE HAGUE / DORDRECHT / LANCASTER Distributors for the United States and Canada: Kluwer Boston, Inc., 190 Old Derby Street, Hingham, MA 02043, USA for all other countries: Kluwer Academic Publishers Group, Distribution Center, P.O.Box 322,3300 AH Dordrecht, The Netherlands Library of Congress Cataloging in Publication Data Feldberg, Michiel A. M. Computed tomography of the retroperitoneum. (Series in radiology; 8) Includes bibliographical references and index. 1. Gerota's fascia--Radiography--Atlases. 2. Retro peritoneum--Radiography--Atlases. 3. Tomography- Atlases. I. Title. II. Series. [DNLM: 1. Retroperi toneal space--Radiography--Atlases. 2. Tomography, X-r~ computed--Atlases. Wl SE719 v. 8/ WI 17 F3l2c J RC904.F44 1983 617'.55 83-4118 ISBN-13: 978-94-009-6716-8 e-ISBN-I3: 978-94-009-6714-4 001: 10.1007/978-94-009-6714-4 Copyright © 1983 by Martinus Nijhoff Publishers, Boston. Softcover reprint of the hardcover 1s t edition 1983 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publishers, Martinus Nijhoff Publishers, 190 Old Derby Street, Hingham, MA 02043, USA. CONTENTS Foreword IX Acknowledgements XI Introduction XIII 1. CASE MATERIAL AND METHODS 1 1.1. Case materials 1 1.2. CT techniques 1 1.3. Patient preparation and contrast enhancement 1 2. REVIEW OF THE LITERATURE. ANATOMIC CONSIDERAn ONS. IDENTIFICATION BYCT 7 2.1. Introduction 7 2.2. History 7 2.3. Compartments of the retroperitoneum 8 2.3.1. Anatomy of the anterior pararenal space and CT identification 8 2.3.2. Anatomy of the perirenal space and CT identification 13 2.3.3. Anatomy of the posterior pararenal space and CT identification 19 2.4. Arrangements of the renal fascia 20 2.4.1. Introduction 20 2.4.2. Embryology 21 2.4.3. Histology 21 2.4.3.1. Review of literature 21 2.4.3.2. Original studies 22 2.4.4. Identification by CT of the renal fascia 22 2.4.4.1. Limitations of CT technique 22 2.4.4.2. When is the renal fascia called normal on CT 25 2.4.4.3. Vascularity of renal fascia: bolus technique 28 2.4.5. Cranial extent of anterior renal fascia: anatomy and identification by CT 28 2.4.6. Lateral extent of both renal fasciae: anatomy and identification by CT 38 2.4.7. Medial extent of anterior renal fascia and its relation to the contralateral fascia: anatomy and identification by CT 40 2.4.8. Cranial and medial extension of posterior renal fascia: anatomy and identification by CT 45 2.4.9. Medial fusion of anterior and posterior ipsilateral renal fascia: anatomy and identification by CT 46 2.4.10. Location of the ureter: anatomy and identification by CT 50 2.4.11. Apex of the perirenal cone: anatomy and identification by CT 50 2.4.12. Significance of fibrous strands in retroperitoneum: identification by CT 55 3. GEROTA'S FASCIA AND INTRAABDOMINAL FLUID 57 3.1. Hemorrhage in retroperitoneum 57 3.1.1. General considerations 57 VI 3.1.2. CT findings and illustrative cases 58 3.2. Urinary" extravasation in retroperitoneum 64 3.2.1. General considerations 64 3.2.2. CT findings and illustrative cases 68 3.3. Acute and chronic inflammation of organs and structures in the retroperitoneal subspaces 74 3.3.1. Introduction 74 3.3.2. Infections in anterior and pararenal space 77 3.3.2.1. General considerations and illustrative non-pancreatic cases 77 3.3.2.2. Pancreatic and peripancreatic fluid collections: general considerations 77 3.3.2.3. CT findings and illustrative cases 79 3.3.3. Infections in perirenal space 82 3.3.3.1. CT findings and illustrative cases in infectious renal disease: acute pyelonephritis, renal abscess, infected renal cyst, xanthogranulomatous pyelonephritis, tuberculo sis of the kidney, renal echinococcosis and 'chronic atrophic pyelonephritis' 82 3.3.3.2. CT findings and illustrative cases in perirenal abscess 99 3.3.4. Infections in posterior pararenal space 103 3.3.4.1. General considerations. CT findings and illustrative cases 103 3.3.5. Muscular abscesses next to the retroperitoneum: iliopsoas muscle 103 3.3.5.1. General considerations 103 3.3.5.2. CT findings and illustrative cases 104 3.3.6. Infections in the midline 106 3.3.6.1. General considerations and CT findings 106 3.3.7. Miscellaneous group: Perianeurysmal fibrosis and idiopathic retroperitoneal fibrosis 107 3.3.7.1. Perianeurysmal fibrosis: CT findings and illustrative cases 107 3.3.7.2. Idiopathic retroperitoneal fibrosis: CT findings and illustrative cases 108 3.4. Intraperitoneal fluid 109 3.4.1. General considerations 109 3.4.2. CT findings and illustrative cases 113 4. GEROTA'S FASCIA AND INFILTRATING MALIGNANCIES 125 4.1. Primary retroperitoneal tumors 125 4.1.1. General considerations 125 4.1.2. CT findings and illustrative cases 125 4.2. Renal cell carcinoma 127 4.2.1. General considerations 127 4.2.2. CT findings and illustrative cases 130 4.2.3. Recurrence of renal cell carcinoma after nephrectomy. CT findings and illustrative ca ses 136 4.3. Renal pelvis carcinoma 137 4.3.1. General considerations 137 4.3.2. CT findings and illustrative cases 138 4.4. Wilms' tumor (nephroblastoma) 140 4.4.1. CT findings and illustrative cases 140 4.5. Adrenal tumors 142 4.5.1. General considerations 142 4.5.2. CT findings and illustrative cases 143 4.6. Pancreatic tumor 149 4.6.1. CT findings and illustrative cases 149 4.7. Duodenum and ascending or descending colon tumor 153 VII 4.7.1. CT findings and illustrative cases 153 5. GEROTA'S FASCIA ASSOCIATED WITH LYMPH NODE DISEASE OF THE RETROPE RITONEUM 159 5.1. General considerations 159 5.2. CT findings and illustrative cases 159 Discussion of the Results 169 Summary 173 List of References 175 Subject Index 187 FOREWORD With the advent of CT we entered a new area of radiological imaging. Structures which rarely if ever were seen became apparent. In no part of the body was the impact of CT as profound as it was in the retroperitoneum. In the pre-CT area this region of the body could not be directly studied and only when gross abnormalities were present could they be appreciated. The best we could do was to try to identify a suspected process by studying its effect on surrounding organs whose position might have been affected by the growth. Urography, barium studies or angiography were employed in the hope that variation in the position of the vessels, ureter or bowel would lead us to the correct diagnosis. With computed tomography all this changed. Modern scanners, available to all today, permit us to appreciate details undreamed of only few years ago. The abundance of fat in this region helps to clearly show even the smallest of structures. We now have the ability to recognize small vessels, lymph nodes and fascial planes. We had a tool which permitted us to study structures which hitherto were only seen by the anatomist or during surgical dissection. Dr. Feldberg studied the retroperitoneum and reported his findings in a new and unique concept. He chose the retroperitoneal fascial planes as the centre of his work, studied their anatomy, the many variations and correlated these findings with the disease processes in and around organs, which affected or were affected by the fascial planes. Anatomists and later clinicians have written extensively about this region. Anatomical studies were based on cadaver dissections. Many, often conflicting theories emerged. Dr. Feldberg methodically and thoroughly reviewed all of these studies and compared them with what he has learned from reviewing more than 5.000 scans of patients. In this text he reports his conclusions. Using the fascial planes as centres of the presentation is somewhat alien to most of us but it is a superb and unique way to allow us to understand these complex structures, how they function and what their purpose is. Like all basic and thorough studies a large number of variants had to be described. The reading on occasion may be difficult, but those who want to understand these anatomic and pathophys iological processes will be rewarded for their effort. It is necessary for one who wants to understand this region in depth to be familiar with the border lines between the normal, normal variants and the abnormal. By mixing the text with superb CT images Dr. Feldberg has beautifully demonstrated this new dimension in retroperitoneal imaging. The extensive literature on the subject has been investigated and incorporated in the text. It is undoubtfully the most complete reference book on the subject. The study of this area which in the past has been the domain reserved for the anatomist and surgeon has now been opened to all. Because our studies are in the living patient, understanding of the spread of disease is now possible. Old and new techniques are combined and the result is a most thorough study of the retroperitoneal fascial planes. P. RUBEN KOEHLER M.D. SALT LAKE CITY, UTAH. ACKNOWLEDGEMENTS The author wishes to thank his associate Paul van Waes, M.D, for his enthusiastic stimulations of writing this book. For proofreading and supplying critical comments he graciously wants to thank Ruben P. Koehler, M.D., Salt Lake City and Hugh Saxton, M.D., London. A special note of gratitude is addressed to the residents and the many radiologic technologists who performed and monitored the CT-studies. This appreciation holds also for Jan Kees Vette, M.D., pathologist and radiologist for his assistance in preparing the pathological specimen. I would also like to express my appreciation to Jan de Groot and his staff for the excellent photographic reproductions, Ingrid Janssen for preparing the anatomical drawings and Joke van den Bos for preparing the manu script. Finally I would like to acknowledge the Heads of the Department of Radiodiagnosis at the University Hospital Utrecht, Carl Puijlaert, M.D. and Kees Klinkhamer, M.D., and Henk Damsma, M.D., Sjef Ruijs, M.D., Peter Kramer, M.D., James Muller, M.D., and Willem Mali, M.D. for providing the proper Academic atmosphere which made it possible to create this work. INTRODUCTION One of the tasks of the radiologist is to recognize, by means of imaging procedures, anatomic structures described in textbooks or specific papers. When new modalities are developed they may assist in shedding light on anatomical and functional problems, as well as visualizing anatomic structures of the human body. X-ray computed tomography (CT) is one such new modality. CT has proved extremely valuable in visualizing the normal and abnormal retroperitoneum (378) since it displays the anatomy well in a tomographic cross-sectional mode. Recently direct coronal (193, 208, 352, 353) and sagittal planes have been added (354, 355). The fact that the retroperitoneal renal fascial planes can be readily visualized allows the differentiation of intra- from retroperitoneal processes. Since 1979 the striking CT appearances of the renai fasciae have aroused our interest. We wanted to investigate the importance of the renal fascia, originally described by Gerota in 1895 (112) and therefore commonly referred to as Gerota's fascia. The peculiar reaction pattern of the renal fascia, i.e. thickening of the fascia (generalized, localized or on which side the fascia is blurred) is therefore the subject of this study. Most authors describe specific disease processes and only mention reactions of Gerota's fascia in a secondary manner. In contrast, this study will place the renal fascia as the central entity and the different etiological conditions affecting it in secondary light. Since with modern third and fourth generation CT machines, structures as delicate as the renal fascia can be depicted, the following questions arise: 1. What is the true anatomy of Gerota's fascia as seen in CT-images? Current literature as well as textbooks display a variety of theories, some conflicting. Is there a single correct version of the anatomy apart from anatomical variations? 2. What is the role of Gerota's fascia in modifying the passage of retroperitoneal fluid such as hemorrhage, urinary extravasation and inflammation? Does the renal fascia also react in intraperitoneal fluid? 3. How does the renal fascia react in malignancies? Is there different behaviour between inflamma tion and malignancy? 4. Is it influenced by lymphadenopathy? 5. Does the thickness of the renal fascia change after treatment? Chapter 1 describes the patient material studied, some aspects of CT techniques and patient handling. Chapter 2 describes the anatomy of the renal fascia based upon reports derived from the literature and is followed by our CT observations in more than 5000 abdominal CT examinations. In short it is an anatomical CT atlas. Chapters 3, 4 and 5 deal with reactions of the fascial structures in different pathological conditions caused by major disease entities. The patients were scanned for these diseases, of which anatomical topographical appearances and spread are described in the general considerations, followed by CT findings and illustrative cases, combined with abstracted experience from other workers. The aim of these chapters is to provide a descriptive clinical pathological CT atlas of a range of conditions involving retroperitoneum and neighbouring organs and structures (excluding the pelvic part of the retroperitoneum).